Indian Patents. 254685:A LOW PRESSURE CASTING MACHINE HAVING A TEMPERATURE SENSOR FOR DIRECTLY DETECTING TEMPERATURE OF MOLTEN METAL

Title of Invention	A LOW PRESSURE CASTING MACHINE HAVING A TEMPERATURE SENSOR FOR DIRECTLY DETECTING TEMPERATURE OF MOLTEN METAL
Abstract	A temperature sensor (26) is located in a lower die (12) at a position (runner 21) where molten metal (5) solidifies later than at cavities (14, 18). A temperature detecting section (28a) of the temperature sensor (26) comes in direct contact with the molten metal (5).

Full Text	Specification CASTING MACHINE Field of the Invention [0001] The present invention relates to a casting machine using a temperature sensor for directly detecting a temperature of molten metal. Background Art [0002] Conventionally, a cylinder head for a motorcycle engine is made by a low pressure casting method, for example. JP-B-3201930 discloses this type of lowpressure casting machine . The casting machine disclosed in this patent document has: a die including a lower and an upper die; and a crucible disposed below the die; and is designed to pressurize molten metal reserved in the crucible to force it up through a stalk to be supplied to a sprue of the lower die. [0003] For the purpose of improvement in productivity, the operation processes of the casting machine from the start of molten metal supply to die opening are automated. To be more specific, after an operator turns a start switch on, the casting machine calculates the time period for which molten metal is supplied (hereinafter referred to as pressurizationtime) based on the die and molten metal temperatures, to pressurize the molten metal during this pressurization time and then supply it into the die. A temperature sensor embedded in the die detects the die temperature, while another temperature sensor provided in the crucible detects the molten metal temperature. The preset pressurization time is so long that the molten metal fills the die after the pressurization start and a solidifying region of the molten metal expands from the upper to lower parts of the die to reach inside of the sprue. [0004] In other words, completing pressurization of the molten metal after the lapse of the pressurization time allows the 1 unsolidified metal to flow from the sprue through the stalk to drop back into the crucible. Only the solidified molten metal remains inside the sprue. Under this condition, the solidified casting in the die has no flowability but is still soft enough to be easily deformed if it is taken out of the die. This substantially decreases the die shape and dimension accuracies . Thus, this casting machine is designed to open the die after a standby period during which the casting becomes hard enough not to deform after pressurization of the molten metal is completed. A time period from the point in time at which pressurization of the molten metal is completed until the point in time at which the die is opened (hereinafter referred to as solidification time) is obtained by calculation based on the die temperature at the time when the molten metal supply is stopped. Disclosure of the invention Problem to be Solved by the Invention [0005] In the conventional type of casting machine configured as described above, there is a need for detecting pressurization time and solidification time with more accuracy. This is because resulting castings may be defective if such times are inaccurate. In the conventional type of casting machine, however, the pressurization and solidification times are both calculated based on the die temperature, and the molten metal temperature detected by the temperature sensor in the crucible, resulting in a limitation of accurate determination of those times. [0006] Further, in the conventional type of casting machine, the timings to complete pressurization of the molten metal and to open the die are unnecessarily delayed sometimes. This leads to a problem with a longer cycle time and therefore a decrease in productivity. These delayed timings result from the pressurization and solidification times, which are set long enough to ensure that the pressurization and solidification of 2 the molten metal are completely done. [0007] The die for this type of casting machine is sometimes over-cooled by blowing high-pressure air for removing sand particles from the destroyed core after die opening, or installing a core used for next casting cycle for an unnecessarily long time. This makes it difficult to keep the die temperature constant at the start of the casting process. As the die temperature at the start of the casting process is relatively lower, the solidification time for the molten metal becomes shorter. In contrast, as the die temperature at the start of the casting process is relatively higher, the solidification time for the molten metal becomes longer. In other words, in the conventional type of casting machine, the pressurization and solidification times are predetermined long enough to produce a non-defective casting product even if there are variations in temperature of the die as described above. [0008] The present invention is made in view of the foregoing problems, and the object of the invention is to provide a casting machine with improved productivity attained by minimizing the cycle time of the casting process to a period required for the casting to be a non-defective product. Means for Solving the Problem [0009] In order to achieve the above object, the present invention provides a casting machine including a temperature sensor for detecting a temperature to be used to control operation timing, in which the temperature sensor is located at a position where solidification occurs later than at a cavity of a die, such that a temperature detecting section of the temperature sensor comes in direct contact with molten metal. Effect of the Invention [0010] As described above, in the casting machine according to the inventions of Claims 1 through 3, the temperature sensor 3 is used to directly detect the temperature of the molten metal that solidifies later than at the cavity. This allows the molten metal supply to stop or the die to open when the temperature of the casting reaches an optimum temperature for stopping the molten metal supply or opening the die . As a result, in the casting machine according to these inventions, it is possible to reduce the supply time for the molten metal and the solidification time, from the stop of the molten metal supply to die-opening, to a period required for casting without any defective product as soon as possible. This therefore further improves the productivity with the reduced casting cycle time. [0011] In the invention of Claim 4, the temperature in the molten metal can be detected. In addition, the temperature detecting section of the temperature sensor can be removed easily from the casting after the casting process. Thus, in the casting machine according to this invention, it is possible to prevent the temperature detecting section from •being broken when the die is opened or the casting is separated from the die while detecting the temperature of the molten metal with high accuracy. [0012] In the inventions of Claims 5 and 6, a region adjacent to the boarder between the sprue and runner in the lower die is located outside of the product part of the casting, and the molten metal filling the region thus has a temperature approximately equal to the temperature of the molten metal in the product part of the casting, and therefore solidifies generally in the same manner as the product part slightly after the solidification occurs therein. Thus, the temperature outside of the product part of the casting detected with the temperature sensor is equivalent to the temperature in the product part of the casting. So, in the low-pressure casting machine according to these inventions, although the temperature sensor directly detects the temperature of the molten metal, no trace of the temperature sensor remains on the product part, 4 thereby achieving production of a quality casting [0013] In the invention of Claim 7, the low-pressure casting machine directly detects the temperature of the molten metal and determines the timings to complete the pressurization of the molten metal and open the die based on the detected temperature. This ensures that the pressurization of the molten metal is completed and the die is opened in the timeliest manner in accordance with the conditions of the casting, even if there are variations in temperature of the die at the start of the casting process. Thus, according to this invention, there is no need to unnecessarily extend or shorten the pressurization and solidification times for the molten metal, or the pressurization and solidification times can be minimized to a period required for the casting to be a non-defective product. This makes it possible to provide the low-pressure casting machine with further improved productivity. [0014] In the inventions of Claims 8 and 9, the gravity casting machine directly detects the temperature of the molten metal and determines the timing to open the die based on the detected temperature. This ensures that the die is opened in the timeliest manner in accordance with the conditions of the casting, even if there are variations in temperature of the die at the start of the casting process. Therefore, according to these inventions, there is no need to unnecessarily extend or shorten the solidification time for the molten metal, or the solidification time can be minimized to a period required for the casting to be a non-defective product. This makes it possible to provide the gravity casting machine with further improved productivity. Brief Description of Drawings [0015] FIG. 1 is a front view, showing a configuration of a low-pressure casting machine. 5 FIG. 2A is an enlarged vertical sectional view of dies. FIG. 2B is an enlarged cross-sectional view of the dies. FIG. 3 is an enlarged cross-sectional view of an essential part. FIG. 4 is a sectional view of a temperature sensor. FIG. 5 is a flowchart for the purpose of explaining the operation of the casting machine. FIG. 6 is a graph, illustrating how a molten metal temperature changes in a runner. FIG. 7 is a sectional view, showing another example of installing the temperature sensor at a sprue of the low-pressure casting machine. FIG. 8A is a cross-sectional view of the dies used for a gravity casting machine. FIG. 8B is a vertical cross-sectional view of the dies used for the gravity casting machine. FIG. 9A is a cross-sectional view of the dies used for the gravity casting machine. FIG. 9B is a vertical cross-sectional view of the dies used for the gravity casting machine. FIG. 10 is a flowchart for the purpose of explaining the casting operation. FIG. 11 is a graph, illustrating how a molten metal temperature changes. Best Mode for Carrying Out the Invention [0016] (First Embodiment) Now, an embodiment of this invention is described with reference to the drawings. In FIGs. 1 through 6, reference numeral 1 denotes a low-pressure casting machine of the first embodiment. The casting machine 1 is designed to cast a cylinder head (not shown) for a motorcycle engine in a low-pressure casting process. As has been well known, the casting machine 1 includes a furnace 2, a die 3 disposed above the furnace 2, and a controller 4, which will be described later, for controlling temperatures of 6 the die 3 and the molten metal 5, operations to open and close the die 3, supply/non-supply of the molten metal 5 and the like. The metal used for casting by the casting machine 1 is aluminum alloy. [0017] The furnace 2 includes a main unit 6 formed into a box shape with an upward opening; a lid 7 for covering this upward opening of the main unit 6; a crucible 8 for reserving the molten metal 5; a stalk 9 attached to the lid 7 with its lower end dipped in the molten metal .5; and the like. The main unit 6 of the furnace 2 has a built-in heater (not shown) for heating the molten metal 5 in the crucible 8 to a predetermined temperature, and connects to a pressurization device 10. The pressurization device 10, designed to pressurize the upper surface of the molten metal 5 to get it out into the stalk 9 by supplying inert gas into the main unit 6, is connected to a connection port 6a formed in the main unit 6 through a gas pipe (not shown) . The controller 4, which will be described later, controls pressurization pressure from the pressurization device 10 and temperature of the heater. [0018] In the casting process of the casting machine 1, the pressurization device 10 pressurizes the inside of the main unit 6 of the furnace 2 with the die 3 clamped as is the case with the conventional casting machine. During the casting process, pressurizing the inside of the main unit 6 forces the molten metal 5 up from the crucible 8 into the stalk 9 and then into the die 3 located above the stalk 9. As shown in FIGs . 2A and 2B, the die 3 includes an upper die 11 and a lower die 12, and is supported by a drive unit 13 (See FIG. 1) . The upper die 11 has a cavity 14 formed with a downward opening and is attached to a platen 15 of the drive unit 13. The cavity 14 refers to a recess for forming the product part of the casting. The platen 15 is supported on a base 16 of the drive unit 13 for up/down movement through a tie bar 17, so that it is movable upward/downward by an up/down movement motor 7 15a. The rotation of the up/down movement motor 15a is controlled by the controller 4 which will be described later. [0019] The lower die 12 has a cavity 18 formed with an upward opening, and is fixed onto the base 16 by a support member 19. The lower die 12 and the upper die 11 are provided with a heater (not shown) for preheating them to a temperature ready for casting and a water-cooling device (not shown) for maintaining the die temperature during the casting process. The controller 4 controls the heater temperature and turning ON/OFF of the water-cooling device. As shown in FIGs. 2A, 2B and 3, at the inner bottom of the lower die 12 is formed a runner 21 that extends from one side of the cavity 18 to the other, as well as a sprue 22 that extends downward from the bottom of the runner 21. [0020] As shown in FIG. 2B, the sprue 22 is formed at the bottom of the lower die 12 so as to have an elliptic shape when viewed from above, by drilling to create a draft angle such that an opening diameter of the sprue 22 becomes larger toward the top as shown in FIG. 3. Awire mesh filter 23 for preventing foreign materials from entering inside the die 3 is attached to the opening at the upper end of the sprue 22. The bottom end of the sprue 22 is connected to the top end of a sprue cup 24 provided in the support member 19. [0021] The sprue cup 24 runs through the support member 19 in the vertical direction. The molten metal 5 is supplied from the top end of the stalk 9 (See FIG. 1) which comes into contact with the bottom surface of the support member 19. To be more specific, during the casting process, the molten metal 5 flows from the stalk 9 through the sprue cup 24 into the sprue 22 from which the molten metal 5 passes through the filter 23 into the runner 21 to be supplied into the cavities 14, 18. The molten metal 5, filling the die 3 in this manner, starts solidifying within the cavities 4, 18 {a product part 25 (See FIG. 3)}. A 8 solidifying region of the molten metal 5 expands from the runner 21 to the sprue 22 with the lapse of time. [0022] As shown in FIG. 3, a temperature sensor 26 for detecting the temperature of the molten metal 5 is attached to the lower die 12. The temperature sensor 26, as shown in FIG. 4, includes a protective metal fitting 28, which includes: a protective portion 26a extending in the vertical direction; a support portion 2 6b formed, at the base end of the protective portion 26a, into one body together with the protective portion 26a; and a through hole 27 axially passing through the protective metal fitting 28. The temperature sensor 26 also includes a thermocouple inserted in the through hole 27. The temperature sensor 26 is fitted into a mounting hole 30 drilled in the lower die 12. [0023] As shown in FIG. 3, the mounting hole 30 consists of a small diameter portion 30a, having an opening in the runner 21, into which the protective portion 26a is fitted, and a large diameter portion 30b, having an opening directed outward of the die, into which the support portion 2 6b is fitted. Also, the mounting . hole 30 is drilled such that it extends through the lower die 12 in the die-opening direction (the vertical direction in FIG. 3) adjacent to the side of the sprue 22 in the lower die 12. In other words, as a result of inserting the temperature sensor 26 into the mounting hole 30, the temperature sensor 26 is located where the molten metal 5 solidifies later than at cavities 14, 18. [0024] As shown in FIG. 4, the support portion 26b fitted in the large diameter portion 30b permits no movement of the protective metal fitting 28 mounted to the lower die 12, so that it cannot be inserted further inward of the die 11 from the position shown in the drawing. The protective metal fitting 28 and the lower die 12 are made of the same material. In the first embodiment, alloy tool steel (SKD) for hot dies is employed. 9 [0025] The length of the protective metal fitting 28, fitted in the mounting hole 30 together with the support portion 26b, is so designed that a temperature detecting section 28a or the top end of the protective metal fitting 28 protrudes into the runner 21. The temperature detecting section 28a is formed, having an outside diameter gradually smaller toward the top end, as shown in FIG. 4. In other words, the temperature detecting section 28a is formed with a draft angle or taper. [0026] In the first embodiment, the temperature detecting section 28a has a dome-shaped tip portion 28b that, is convex upward, to which each top end of two types of conductor 29a, 29b of the thermocouple 29 is welded. To be more specific, each top end of the conductors 29a, 29b passing the through hole 27 faces the opening of the tip portion 28b, in order to be welded together to block the opening using a welding electrode made of common material, alloy tool steel (SKD) for hot dies. The welded opening is then ground into a dome-shape. [0027] The well-known, typical alumel-chromel thermocouple 29 is used. It includes the two types of conductor 29a, 29b which conduct each other by welding to the tip portion 28b. Providing the thermocouple 29 in this manner allows the temperature sensor 26 to detect the temperature of the molten metal 5 which comes into contact with the tip portion 28b (where the thermocouple 29 is welded) of the protective metal fitting 28 (protective portion 26a). [0028] The two conductors 29a, 29b running through the protective portion 26a to the support portion 26b are lead outside of the lower die 12. They are connected to the controller 4 through the interior of a stainless duct 31 welded to the support portion 2 6b. In the temperature sensor 26 of the first embodiment, refractory insulating powder 27 is filled around the conductors 23a, 23b in the through hole 27. As the refractory insulating 10 powder 32, there may be magnesia (MgO) used for a glow plug of diesel engines, for example. [0029] The controller 4 includes a molten metal temperature controller 33; a die temperature controller 34; a pressurization pressure controller 35; and a casting condition setter 36, as shown in FIG. 1. The molten metal temperature controller 33 controls the temperature of the heater of the furnace 2 so as to heat the molten metal 5 in the crucible 8 at a predetermined temperature. The casting condition setter 36, which will be described later, determines the temperature of the molten metal 5 for each die used. [0030] The die temperature controller 34 controls the temperatures of the heater and the cooling device in the die 3 so as to heat the die 3 at a predetermined temperature. The casting condition setter 36 determines the temperature of each die 3 used. The pressurization pressure controller 35 switches on/off the pressurization device 10, while controlling the amount of gas to be supplied from the pressurization device 10 so as to make the feed rate of the molten metal 5 from the crucible 8 into the die 3 equal to a predetermined rate. The casting condition setter 36 determines the predetermined feed rate for each die used. [0031] By the casting condition setter 36, data related to the casting conditions, such as the die and molten metal temperatures, the pressurization and solidification times, and the feed rate of the molten metal 5, in accordance with each die used for the casting process, are sent to the molten metal temperature controller 33, the die temperature controller 34 and the pressurization pressure controller 35. The casting condition setter 36 outputs start/stop signals for the pressurization pressure controller 35 to start/stop 11 pressurizing the molten metal 5 at the respective predetermined timings. The casting condition setter 36 also outputs die-opening/clamping signals for the drive unit 13 to move the upper die 11 up/down respectively at the predetermined timings. [0032] Of these start/stop signals and die-clamping/opening signals, the stop and die-opening signals are sent when the temperature detected with the temperature sensor 26 reaches predetermined temperatures Tl, T2, respectively (See FIG. 6) The temperature Tl is optimum for completing pressurization of the molten metal 5, and so predetermined that there is no flowability of the molten metal 5 in the product part, the runner part, and the upper part of the sprue due to the solidification therein while the flowability of the molten metal 5 remains on the stalk 9 side from the upper part of the sprue. [0033] In other words, the temperature Tl is predetermined to be the maximum value at which the molten metal 5 only on the stalk 9 side below the upper part of the sprue flows down toward the crucible 8 side even if the pressurization device 10 stops pressurization. As shown in FIG. 3, in the first embodiment, the temperature Tl is so predetermined that the upper portion of the filter 23 can remain in the casting. The temperature T2, lower than the temperature Tl, is optimum for opening the die, and predetermined to be the maximum value at which the molten metal 5 solidifies enough not to have changed casting shape and dimension at die opening. [0034] The casting condition setter 36 of the first embodiment is designed to produce non-defective products even if it is impossible for the temperature sensor 26 to detect the temperatures Tl, T2 due to some malfunction. In other words, the casting condition setter 36 is designed to determine the timings to complete the pressurization of the molten metal 5 12 and to open the die based on the times (pressurization and solidification times), instead of the temperature detected by the temperature sensor 26, for failure of the temperature sensor 26. [0035] To be more detailed, the casting condition setter 36 is designed to complete the pressurization of the molten metal 5 when the predetermined pressurization time has elapsed since the start of the pressurization of the molten metal 5 in the case that the temperature sensor 26 is a defective product or has some malfunction. The casting condition setter 36 is also designed to open the die when the predetermined solidification time has elapsed since the completion of the pressurization of the molten metal 5. [0036] The pressurization time refers to a time period from the point in time when a supply of the molten metal 5 starts to the point in time when a solidifying region of the molten metal 5 expands to the sprue 22. This pressurization time is obtained by calculation, in accordance with the type of die 3 used, based on the temperature of the die 3 at the start of supplying the molten metal 5, and the temperature of the molten metal 5 in the crucible 8. The solidification time refers to a period required for the casting inside of the die 3 to solidify enough not to easily deform after the completion of the pressurization of the molten metal 5. This solidification time is obtained by calculation, depending on the type of die 3, based on the temperature of the die 3 at the completion of the pressurization of the molten metal 5. These pressurization and solidification times may be stored in a memory (not shown) as a map in advance and read from the memory as needed. [0037] The aforementioned operation of the casting machine 1 are next described in conjunction with the further detailed configuration of the controller 4 with reference to FIGs. 5 and 6. Here, only one operation cycle (one shot) of the casting 13 work, which is repeatedly performed, is described. It is therefore assumed that the casting conditions for each die 3 have been already inputted in the casting condition setter 36, and the temperatures of the die 3 and molten metal 5 have already reached the targeted casting temperature. Inputs of the casting conditions are achieved by inputting a predetermined number given to an execution program for each die 3. [0038] The casting work of the casting machine 1 with the die 3 clamped is started by, for example, turning the start switch (not shown) ON. When the start switch is turned ON, the casting condition setter first determines whether or not the current temperatures of the die 3 and the molten metal 5 fall within a range for producing non-defective products, as shown in the step S1 of FIG. 5. The range for producing non-defective products refers to a temperature range within which the casting can be a non-defective product, which is predetermined for each die. If NO or the aforementioned temperatures fall out of the range for producing non-defective products, the process goes to the step S2 and performs an alarm process in which the casting condition setter 36 gives an operator notice of the abnormal temperatures. This results in stopping the casting operations. [0039] If YES, the casting condition setter 36 calculates the pressurization time of the molten metal 5 (the step S3) which is essential for executing the casting program to be used in the case the temperature sensor 26 fails to function. The casting condition setter 36 then sends the start signal to the pressurization pressure controller 35 together with the data for the feed rate of the molten metal 5 in the step S4. The start signal sent to the pressurization pressure' controller 35 in this manner causes the pressurization device 10 to supply inert gas into the furnace 2, and the pressurized molten metal 5 is supplied from the stalk 9 through the sprue cup 24, the sprue 22 and the filter into the die 3. Part of the molten metal 5 filling the cavities 14, 18 first solidifies in the product 14 part 25 within the cavities 14, 18. A solidifying region of the molten metal 5 expands from the runner 21 down to the sprue 22 with the lapse of time. In addition, when the pressurization device 10 starts the pressurization as described above, a timer (not shown) also starts simultaneously. [0040] After that, the casting condition setter uses the temperature sensor 2 in the lower die 12 to detect the temperature of the molten metal 13 in the runner 9 in the step S5. As shown in FIG. 6, the temperature detected with the temperature sensor 26 sharply increases after the start of casting (after the start of supplying the molten metal 5) , then remains unchanged (with the molten metal 5 flowing in the runner 21) for a certain period of time, and then gradually decreases. In the step S6, the casting condition setter 36 compares the maximum temperature detected with the temperature sensor 26 with a predetermined temperature range. If the maximum temperature falls within the predetermined temperature range, the casting condition setter 36 determines that the temperature sensor 26 works properly. In contrast, if the maximum temperature falls out of the predetermined temperature range, it determines that the temperature sensor 26 does not work properly (is in an abnormal condition).. [0041] In the case it is determined that the temperature sensor 26 is in an abnormal condition in the step S6, when the elapsed time indicated by the timer reaches the pressurization time obtained in the step S3, the casting condition setter 36 sends the stop signal to the pressurization pressure controller 35. Then the pressurization pressure controller 35 receives the stop signal, which causes the pressurization device 10 to stop the inert gas supply, thereby completing the pressurization of the molten metal 5 (the step S7) . Approximately at the same time when the supply of the molten metal 5 is stopped, the casting condition setter 36 calculates the solidification time based on the current temperature of the die 3 (the step S8) . 15 [0042] After the stop of supplying the molten metal 5 in the step S7, the unsolidified metal 5 in the die flows from the sprue 22 through the sprue cup 24 and the stalk 9 to drop back into the crucible 8 . The molten metal 5 remaining in the die 3 (with no flowability) further solidifies with increased hardness as the result of no heat supply (the step S9) . When the pressurization of the molten metal 5 is completed, the timer (not shown) starts. Then, the casting condition setter 36 sends the die-opening signal to the drive unit 13 after the time indicated by the timer reaches the solidification time. Then the drive unit 13 receives the die-opening signal, which causes the upper die 11 to move up to open the die (the step 10 to the step 11) . [0043] If YES in the step S6 or it is determined that the temperature sensor 26 works properly, the casting condition setter 36 uses the temperature sensor 26 to detect the temperature of the molten metal 5 in the runner 21 in the step S12. The temperature detected with the temperature sensor 26 varies as shown in FIG. 6. After reaching the maximum temperature, it gradually decreases as the molten metal 5 further solidifies. The casting condition setter 36 sends the stop signal to the pressurization pressure controller 35 when the temperature detected with the temperature sensor 26 decreases to the predetermined temperature Tl (the step S13) . Then the pressurization pressure controller 35 receives the stop signal, which causes the pressurization device 10 to stop the inert gas supply, thereby completing the pressurization of the molten metal 5 (the step S14). [0044] When the pressurization of the molten metal 5 is completed, the unsolidified metal 5 drops back into the crucible 8 while the molten metal 5 having no flowability remains in the die 3. This remaining molten metal 5 further solidifies since its temperature further decreases as the result of no heat 16 supply. The casting condition setter 36 uses the temperature sensor 26 to constantly detect the temperature of the molten metal 5 in the runner part as shown in the steps S15, S16. When the temperature of the molten metal 5 detected with the temperature sensor 26 decreases to the predetermined temperature T2, the casting condition setter 36 determines the completion of the solidification and sends the die-opening signal to the drive unit 13. [0045] The drive unit 13 receives the die-opening signal in this manner, which causes the upper die 11 to move up to open the die (the step Sll). One cycle of the casting work ends. At the die-opening, in either case that the casting moves up with the upper die 11, or the casting remains in the lower die 12, the temperature detecting section 25 of the temperature sensor 2 can be easily removed from the casting when it is separated from the lower die 12. This is because the temperature detecting section 28a of the temperature sensor 26 is formed with a draft angle or taper. As described above, the protective metal fitting 28 including the temperature detecting section 28a and the thermocouple welding part are made of the same material as the die, providing excellent wear resistance. This therefore prevents them from being worn out by castings. [0046] The low-pressure casting machine 1 configured as previously described uses the temperature sensor 26 to directly detect the temperature of the molten metal 5 adjacent to the boarder between the sprue 22 and the runner 21 (temperature of the molten metal 5, which solidifies later than at the cavities 14, 18). Therefore, the low-pressure casting machine 1 can complete the pressurization of the molten metal 5 or open the die when the temperature of the casting reaches the optimum temperature. It is thus possible to minimize the pressurization time for the molten metal 5 and the solidification time, from the completion of the pressurization to die-opening, to a period required for the casting to be a 17 non-defective product. This therefore further improves productivity with the reduced casting cycle time. [0047] The temperature detection section 28a of the temperature sensor 26 used in the casting machine 1 of the first embodiment has a draft angle or taper, and protrudes from the inner wall face of the lower die 12 into the die 3 in the die-opening direction. The temperature sensor 26 thus can detect the temperature of the molten metal 5 in the runner 21 located adjacent to the product part 25, and allows easy removal of the temperature detecting section 28a from the casting after the casting process. Accordingly, the temperature sensor 26 prevents the temperature detecting section 28a from being broken when the die is opened or the casting is separated from the die while detecting the temperature of the molten metal 5 with high accuracy. [0048] In the casting machine 1 of the first embodiment, a region adjacent to the boarder between the sprue 22 and the runner 21 in the lower die 12 is located outside of the product part of the casting 25. The molten metal 5, filling this region, thus has a temperature approximately equal to the temperature of the molten metal in the product part 25, and therefore solidifies generally in the same manner as the product part 25 slightly later than at the product part 25. The casting machine 1 of the first embodiment uses the temperature sensor 26 to detect the temperature of the molten metal 5 located in the region adjacent to the boarder between the sprue 22 and the runner 21. This means that the temperature detected with the temperature sensor 26 is equivalent to the temperature of the product part of the casting 25. Therefore, the timings to complete the pressurization of the molten metal 5 and to open the die can be determined with high accuracy. In other words, in the casting machine 1, there is no need to extend the supply and solidification times to adjust the difference in temperatures between the temperature detecting section and the product part 18 25, as is the conventional case. Accordingly, the cycle time can be reduced. Moreover, in the casting machine 1, no trace of the temperature sensor 26 remains on the product part 25, achieving production of a quality casting. [0049] The casting machine 1 of the first embodiment directly detects the temperature of the molten metal 5, and determines the timings to complete the pressurization of the molten metal 5 and to open the die based on this detected temperature. This ensures that the pressurization of the molten metal 5 is completed and the die is opened in the timeliest manner in accordance with the conditions of the casting, even if there are variations in temperature of the die 3 at the start of the casting process . Thus, there is no need for the casting machine 1 to unnecessarily extend or shorten the pressurization and solidification times for the molten metal 5, or the supply and solidification times can be minimized to a period required for the casting to be a non-defective product. This further improves the productivity. [0050] (Second Embodiment) A temperature sensor may be located at a sprue, as shown in FIG. 7. The figure is a sectional view, showing another example of installing the temperature sensor at the sprue of the low-pressure casting machine. In the figure, components, which are the same as or equivalent to those described with reference to FIGs. 1 through 6, are denoted by their respective common reference numerals, and the detailed descriptions are not repeated as appropriate . A temperature sensor 26 shown in FIG. 7 is mounted to a lower die 12 and a temperature detecting section 28a protrudes to a sprue 22 from its side. At the sprue 22 in the lower die 12 is formed a projection 41 for the purpose of avoiding molten metal 5, which flows up within the sprue 22, from pressuring the temperature detecting section 28a. [0051] 19 The projection 41 is so formed as to cause part of the peripheral wall of the sprue 22 to protrude inward. In the second embodiment, in order to reduce the resistance caused when molten metal 5 flows up within the sprue 22 as soon as possible, the end edge on the protruding side of the projection 41 is inclined so as to be gradually closer to the center of the sprue 22 toward the upper side. A contact portion between the projection 41 and the temperature detecting section 28a has a structure in which the lower half of the temperature detecting section 28a of circular cross-section is fitted into a recess 41a formed on the upper face of the projection 41, so that only the upper half of the temperature detecting section 28a is exposed. The temperature detecting section 28a of the temperature sensor 26 faces inside of the sprue 22, which allows the temperature sensor 26 to directly detect the temperature of the molten metal 5 in the sprue 22. Therefore, the second embodiment can also achieve the same effects as obtained in the first embodiment. [0052] (Third Embodiment) An embodiment of the present invention applied to a gravity casting machine is described in details with reference to FIGs. 8A, 8B through 11. FIGs. 8A and 8B, and 9A and 9B illustrate dies used for the gravity casting machine, in which FIGs. 8A and 9A are cross sectional plan views and FIGs. 8B and 9B are vertical sectional views. FIG. 10 is a flowchart for the purpose of explaining the casting operation. FIG. 11 is a graph, illustrating how the molten metal temperature changes. A gravity casting die 51, as shown in FIGs. 8A and 8B, and 9A and 9B, includes a first die 52 and a second die 53 formed so as to open in the horizontal direction, as well as cavities 54, 55 and risers 56, 57 above the cavities. The first die 52 and the second die 53 are mounted to a die drive unit (not shown) by which the dies are clamped and opened. 20 In the die 51 shown in FIG. 8A and 8B, the molten metal 5 is supplied from the risers 56, 57 into the cavities 54, 55. The die 51 shown in FIG. 9A and 9B has a sprue 58 formed with an upward opening on the side of the risers 56, 57. A structure is employed in which the molten metal 5 is supplied from the sprue 58 through a runner 59 to the bottom of the cavities 54, 55. These dies 51 each have a temperature sensor 26 provided in the risers 56, 57. [0054] The temperature sensor 26 is an equivalent to what is used for the first embodiment, and mounted to the first die 52 with a temperature detecting section 28a protruding from the inner wall face of the riser 56 in the die-opening direction. In other words, also in this case, the temperature sensor 26 is located at a position where the molten metal 5 solidifies later than at the cavities 54, 55. As is the case with the die 51 of FIGs . 9A and 9B, in which the sprue 58 and the runner 59 are used to supply the molten metal 5 to the bottom of the cavities 54, 55, the sprue 58 may be provided with the temperature sensor 26, as shown by a phantom line in FIG. 9B. [0055] The gravity casting machine with the die 51 configured as described above is controlled by a controller (not shown) in a manner shown in FIG. 10. To be more specific, the controller determines whether or not the current temperatures of the die 51 and the molten metal 5 fall within a range for producing non-defective products in the step P1 in the flowchart of FIG. 10. The range for producing non-defective products refers to a temperature range within which the casting can be a non-defective product, which is predetermined for each die. If NO or the aforementioned temperatures fall out of the range for producing non-defective products, the process goes to the step 52 and performs an alarm process in which the controller gives an operator notice of the abnormal temperatures. This results in stopping the casting operations. [0056] 21 If YES, the gravity casting machine uses a molten metal supply device (not shown) or the like to supply the molten metal 5 (pouring) to fill the die 51 (the step P3) . At the pouring, the controller 4 calculates the solidification time of the molten metal 5 which is essential for executing the casting program to be used in the case the temperature sensor 26 fails to function. At the same time, the timer starts. [0057] As mentioned above, after the supply of the molten metal 5 into the die 51, the controller uses the temperature sensor 26 to detect the temperature of the molten metal 5 in the risers 56, 57 or the sprue 58, as shown in the step P4 . The temperature detected with the temperature sensor 26 sharply increases after the casting process start (pouring start), then remains unchanged for a certain time period, and then gradually decreases, as shown in FIG. 11. After that, the controller 4 determines that the temperature sensor 26 works properly if the maximum temperature detected with the temperature sensor 26 falls within a predetermined temperature range in the step P5. In contrast, if the maximum temperature falls out of the predetermined temperature range, it determines that the temperature sensor 26 does not work properly (is in an abnormal condition). [0058] If it is determined that the temperature sensor 26 is in the abnormal condition in the step P5, the controller is in standby until the elapsed time indicated by the timer reaches the solidification time obtained in the step P3 (the step P6) and then sends a die-opening signal to the die drive unit. The die drive unit then receives the die-opening signal in this manner, which causes the die to open (the step P7). If YES in the step P5 or the temperature sensor 26 works properly, the controller uses the temperature sensor 26 to detect the temperature of the molten metal 5 in the step P8 . [0059] The temperature detected with the temperature sensor 26 22 varies as shown in FIG. 11. After reaching the maximum temperature, it decreases as the molten metal 5 further solidifies. When the temperature detected with the temperature sensor 26 decreases to the predetermined temperature T3 (the step P9), the controller uses the die drive unit to open the die (the step P7). The temperature T3 is predetermined to be the maximum value at which the molten metal 5 solidifies enough not to have changed casting shape and dimension at die opening. In this way, the die is opened, which results in completion of one cycle of the casting work. The temperature detecting section 28a of the temperature sensor 26 can be easily removed from the casting when it is separated from the first die after the casting process, since the temperature detecting section 28a is formed with a draft angle or taper. [0060] Thus, the gravity casting machine with the die 51 of the second embodiment uses the temperature sensor 26 to directly detect the temperature of the molten metal 5, and determines the timing to open the die based on this detected temperature. This ensures that the die 51 is opened in the timeliest manner in accordance with the conditions of the casting, even if there are variations in temperature of the die 51 at the start of the casting process. Therefore, in this gravity casting machine, there is no need to unnecessarily extend or shorten the solidification time for the molten metal 5, or the solidification time can be minimized to a period required for the casting to be a non-defective product. This further improves the productivity. Industrial Applicability [0061] The present invention can be applied to a casting machine for casing parts, such as cylinder heads of vehicle engines, marine engines or other general-purpose engines. 23 Claims [1] A casting machine including a temperature sensor for detecting a temperature to be used to control operation timing, wherein the temperature sensor is located at a position where solidification occurs later than at a cavity of a die, such that a temperature detecting section of the temperature sensor comes in direct contact with molten metal. [2] The casting machine according to Claim 1, wherein the operation timing is the timing when molten metal supply is stopped. [3] The casting machine according to Claim 1, wherein the operation timing is the timing when the die is opened. [4] The casting machine according to Claim 1, wherein the temperature detection section of the temperature sensor has a draft angle or taper, and protrudes into the die from the inner wall face thereof in a die-opening direction. [5] The casting machine according to Claim 4, wherein the casting machine is a low-pressure casting machine, and the temperature detection section of the temperature sensor is located at a position adjacent to a boarder between a sprue and a runner in a lower die. [6] The casting machine according to Claim 1, wherein the casting machine is a low-pressure casting machine, and the temperature detection section of the temperature sensor is located at a position adjacent to a boarder between a sprue and a runner in a lower die. [7] The casting machine according to Claim 6, wherein a controller is provided for completing the pressurization of the molten metal when the temperature of the molten metal detected with the temperature sensor reaches a predetermined temperature, and for opening the die when the temperature of the molten metal detected with the temperature sensor reaches a predetermined temperature. [8] The casting machine according to Claim 1, wherein the casting machine is a gravity casting machine, 24 and the temperature detection section of the temperature sensor is provided in a riser of the die, and wherein a controller is provided for opening the die when the temperature of the molten metal detected with the temperature sensor reaches a predetermined temperature. 25 [9] The casting machine according to Claim 1, wherein the casting machine is a gravity casting machine, and the temperature detection section of the temperature sensor is provided at a sprue of the die, and wherein a controller is provided for opening the die when the temperature of the molten metal detected with the temperature sensor reaches a predetermined temperature. A temperature sensor (26) is located in a lower die (12) at a position (runner 21) where molten metal (5) solidifies later than at cavities (14, 18). A temperature detecting section (28a) of the temperature sensor (26) comes in direct contact with the molten metal (5). A temperature sensor (26) is located in a lower die (12) at a position (runner 21) where molten metal (5) solidifies later than at cavities (14, 18). A temperature detecting section (28a) of the temperature sensor (26) comes in direct contact with the molten metal (5).

Full Text

Specification CASTING MACHINE Field of the Invention [0001]
The present invention relates to a casting machine using a temperature sensor for directly detecting a temperature of molten metal. Background Art
[0002]
Conventionally, a cylinder head for a motorcycle engine is made by a low pressure casting method, for example. JP-B-3201930 discloses this type of lowpressure casting machine . The casting machine disclosed in this patent document has: a die including a lower and an upper die; and a crucible disposed below the die; and is designed to pressurize molten metal reserved in the crucible to force it up through a stalk to be supplied to a sprue of the lower die. [0003]
For the purpose of improvement in productivity, the operation processes of the casting machine from the start of molten metal supply to die opening are automated. To be more specific, after an operator turns a start switch on, the casting machine calculates the time period for which molten metal is supplied (hereinafter referred to as pressurizationtime) based on the die and molten metal temperatures, to pressurize the molten metal during this pressurization time and then supply it into the die. A temperature sensor embedded in the die detects the die temperature, while another temperature sensor provided in the crucible detects the molten metal temperature. The preset pressurization time is so long that the molten metal fills the die after the pressurization start and a solidifying region of the molten metal expands from the upper to lower parts of the die to reach inside of the sprue. [0004]
In other words, completing pressurization of the molten metal after the lapse of the pressurization time allows the
1

unsolidified metal to flow from the sprue through the stalk to drop back into the crucible. Only the solidified molten metal remains inside the sprue. Under this condition, the solidified casting in the die has no flowability but is still soft enough to be easily deformed if it is taken out of the die. This substantially decreases the die shape and dimension accuracies . Thus, this casting machine is designed to open the die after a standby period during which the casting becomes hard enough not to deform after pressurization of the molten metal is completed. A time period from the point in time at which pressurization of the molten metal is completed until the point in time at which the die is opened (hereinafter referred to as solidification time) is obtained by calculation based on the die temperature at the time when the molten metal supply is stopped.
Disclosure of the invention Problem to be Solved by the Invention [0005]
In the conventional type of casting machine configured as described above, there is a need for detecting pressurization time and solidification time with more accuracy. This is because resulting castings may be defective if such times are inaccurate. In the conventional type of casting machine, however, the pressurization and solidification times are both calculated based on the die temperature, and the molten metal temperature detected by the temperature sensor in the crucible, resulting in a limitation of accurate determination of those times.
[0006]
Further, in the conventional type of casting machine, the timings to complete pressurization of the molten metal and to open the die are unnecessarily delayed sometimes. This leads to a problem with a longer cycle time and therefore a decrease in productivity. These delayed timings result from the pressurization and solidification times, which are set long enough to ensure that the pressurization and solidification of
2

the molten metal are completely done.
[0007]
The die for this type of casting machine is sometimes over-cooled by blowing high-pressure air for removing sand particles from the destroyed core after die opening, or installing a core used for next casting cycle for an unnecessarily long time. This makes it difficult to keep the die temperature constant at the start of the casting process. As the die temperature at the start of the casting process is relatively lower, the solidification time for the molten metal becomes shorter. In contrast, as the die temperature at the start of the casting process is relatively higher, the solidification time for the molten metal becomes longer. In other words, in the conventional type of casting machine, the pressurization and solidification times are predetermined long enough to produce a non-defective casting product even if there are variations in temperature of the die as described above.
[0008]
The present invention is made in view of the foregoing problems, and the object of the invention is to provide a casting machine with improved productivity attained by minimizing the cycle time of the casting process to a period required for the casting to be a non-defective product. Means for Solving the Problem
[0009]
In order to achieve the above object, the present invention provides a casting machine including a temperature sensor for detecting a temperature to be used to control operation timing, in which the temperature sensor is located at a position where solidification occurs later than at a cavity of a die, such that a temperature detecting section of the temperature sensor comes in direct contact with molten metal. Effect of the Invention
[0010]
As described above, in the casting machine according to the inventions of Claims 1 through 3, the temperature sensor
3

is used to directly detect the temperature of the molten metal that solidifies later than at the cavity. This allows the molten metal supply to stop or the die to open when the temperature of the casting reaches an optimum temperature for stopping the molten metal supply or opening the die . As a result, in the casting machine according to these inventions, it is possible to reduce the supply time for the molten metal and the solidification time, from the stop of the molten metal supply to die-opening, to a period required for casting without any defective product as soon as possible. This therefore further improves the productivity with the reduced casting cycle time. [0011]
In the invention of Claim 4, the temperature in the molten metal can be detected. In addition, the temperature detecting section of the temperature sensor can be removed easily from the casting after the casting process.
Thus, in the casting machine according to this invention, it is possible to prevent the temperature detecting section from •being broken when the die is opened or the casting is separated from the die while detecting the temperature of the molten metal with high accuracy. [0012]
In the inventions of Claims 5 and 6, a region adjacent to the boarder between the sprue and runner in the lower die is located outside of the product part of the casting, and the molten metal filling the region thus has a temperature approximately equal to the temperature of the molten metal in the product part of the casting, and therefore solidifies generally in the same manner as the product part slightly after the solidification occurs therein. Thus, the temperature outside of the product part of the casting detected with the temperature sensor is equivalent to the temperature in the product part of the casting. So, in the low-pressure casting machine according to these inventions, although the temperature sensor directly detects the temperature of the molten metal, no trace of the temperature sensor remains on the product part,
4

thereby achieving production of a quality casting
[0013]
In the invention of Claim 7, the low-pressure casting machine directly detects the temperature of the molten metal and determines the timings to complete the pressurization of the molten metal and open the die based on the detected temperature. This ensures that the pressurization of the molten metal is completed and the die is opened in the timeliest manner in accordance with the conditions of the casting, even if there are variations in temperature of the die at the start of the casting process.
Thus, according to this invention, there is no need to unnecessarily extend or shorten the pressurization and solidification times for the molten metal, or the pressurization and solidification times can be minimized to a period required for the casting to be a non-defective product. This makes it possible to provide the low-pressure casting machine with further improved productivity.
[0014]
In the inventions of Claims 8 and 9, the gravity casting machine directly detects the temperature of the molten metal and determines the timing to open the die based on the detected temperature. This ensures that the die is opened in the timeliest manner in accordance with the conditions of the casting, even if there are variations in temperature of the die at the start of the casting process.
Therefore, according to these inventions, there is no need to unnecessarily extend or shorten the solidification time for the molten metal, or the solidification time can be minimized to a period required for the casting to be a non-defective product. This makes it possible to provide the gravity casting machine with further improved productivity. Brief Description of Drawings [0015]
FIG. 1 is a front view, showing a configuration of a low-pressure casting machine.
5

FIG. 2A is an enlarged vertical sectional view of dies.
FIG. 2B is an enlarged cross-sectional view of the dies.
FIG. 3 is an enlarged cross-sectional view of an essential part.
FIG. 4 is a sectional view of a temperature sensor.
FIG. 5 is a flowchart for the purpose of explaining the operation of the casting machine.
FIG. 6 is a graph, illustrating how a molten metal temperature changes in a runner.
FIG. 7 is a sectional view, showing another example of installing the temperature sensor at a sprue of the low-pressure casting machine.
FIG. 8A is a cross-sectional view of the dies used for a gravity casting machine.
FIG. 8B is a vertical cross-sectional view of the dies used for the gravity casting machine.
FIG. 9A is a cross-sectional view of the dies used for the gravity casting machine.
FIG. 9B is a vertical cross-sectional view of the dies used for the gravity casting machine.
FIG. 10 is a flowchart for the purpose of explaining the casting operation.
FIG. 11 is a graph, illustrating how a molten metal temperature changes. Best Mode for Carrying Out the Invention
[0016] (First Embodiment)
Now, an embodiment of this invention is described with reference to the drawings.
In FIGs. 1 through 6, reference numeral 1 denotes a low-pressure casting machine of the first embodiment. The casting machine 1 is designed to cast a cylinder head (not shown) for a motorcycle engine in a low-pressure casting process. As has been well known, the casting machine 1 includes a furnace 2, a die 3 disposed above the furnace 2, and a controller 4, which will be described later, for controlling temperatures of
6

the die 3 and the molten metal 5, operations to open and close the die 3, supply/non-supply of the molten metal 5 and the like. The metal used for casting by the casting machine 1 is aluminum alloy.
[0017]
The furnace 2 includes a main unit 6 formed into a box shape with an upward opening; a lid 7 for covering this upward opening of the main unit 6; a crucible 8 for reserving the molten metal 5; a stalk 9 attached to the lid 7 with its lower end dipped in the molten metal .5; and the like. The main unit 6 of the furnace 2 has a built-in heater (not shown) for heating the molten metal 5 in the crucible 8 to a predetermined temperature, and connects to a pressurization device 10. The pressurization device 10, designed to pressurize the upper surface of the molten metal 5 to get it out into the stalk 9 by supplying inert gas into the main unit 6, is connected to a connection port 6a formed in the main unit 6 through a gas pipe (not shown) . The controller 4, which will be described later, controls pressurization pressure from the pressurization device 10 and temperature of the heater.
[0018]
In the casting process of the casting machine 1, the pressurization device 10 pressurizes the inside of the main unit 6 of the furnace 2 with the die 3 clamped as is the case with the conventional casting machine. During the casting process, pressurizing the inside of the main unit 6 forces the molten metal 5 up from the crucible 8 into the stalk 9 and then into the die 3 located above the stalk 9.
As shown in FIGs . 2A and 2B, the die 3 includes an upper die 11 and a lower die 12, and is supported by a drive unit 13 (See FIG. 1) . The upper die 11 has a cavity 14 formed with a downward opening and is attached to a platen 15 of the drive unit 13. The cavity 14 refers to a recess for forming the product part of the casting. The platen 15 is supported on a base 16 of the drive unit 13 for up/down movement through a tie bar 17, so that it is movable upward/downward by an up/down movement motor
7

15a. The rotation of the up/down movement motor 15a is controlled by the controller 4 which will be described later.
[0019]
The lower die 12 has a cavity 18 formed with an upward opening, and is fixed onto the base 16 by a support member 19. The lower die 12 and the upper die 11 are provided with a heater (not shown) for preheating them to a temperature ready for casting and a water-cooling device (not shown) for maintaining the die temperature during the casting process. The controller 4 controls the heater temperature and turning ON/OFF of the water-cooling device.
As shown in FIGs. 2A, 2B and 3, at the inner bottom of the lower die 12 is formed a runner 21 that extends from one side of the cavity 18 to the other, as well as a sprue 22 that extends downward from the bottom of the runner 21.
[0020]
As shown in FIG. 2B, the sprue 22 is formed at the bottom of the lower die 12 so as to have an elliptic shape when viewed from above, by drilling to create a draft angle such that an opening diameter of the sprue 22 becomes larger toward the top as shown in FIG. 3. Awire mesh filter 23 for preventing foreign materials from entering inside the die 3 is attached to the opening at the upper end of the sprue 22. The bottom end of the sprue 22 is connected to the top end of a sprue cup 24 provided in the support member 19.
[0021]
The sprue cup 24 runs through the support member 19 in the vertical direction. The molten metal 5 is supplied from the top end of the stalk 9 (See FIG. 1) which comes into contact with the bottom surface of the support member 19. To be more specific, during the casting process, the molten metal 5 flows from the stalk 9 through the sprue cup 24 into the sprue 22 from which the molten metal 5 passes through the filter 23 into the runner 21 to be supplied into the cavities 14, 18. The molten metal 5, filling the die 3 in this manner, starts solidifying within the cavities 4, 18 {a product part 25 (See FIG. 3)}. A
8

solidifying region of the molten metal 5 expands from the runner 21 to the sprue 22 with the lapse of time. [0022]
As shown in FIG. 3, a temperature sensor 26 for detecting the temperature of the molten metal 5 is attached to the lower die 12. The temperature sensor 26, as shown in FIG. 4, includes a protective metal fitting 28, which includes: a protective portion 26a extending in the vertical direction; a support portion 2 6b formed, at the base end of the protective portion 26a, into one body together with the protective portion 26a; and a through hole 27 axially passing through the protective metal fitting 28. The temperature sensor 26 also includes a thermocouple inserted in the through hole 27. The temperature sensor 26 is fitted into a mounting hole 30 drilled in the lower die 12.
[0023]
As shown in FIG. 3, the mounting hole 30 consists of a small diameter portion 30a, having an opening in the runner 21, into which the protective portion 26a is fitted, and a large diameter portion 30b, having an opening directed outward of the die, into which the support portion 2 6b is fitted. Also, the mounting . hole 30 is drilled such that it extends through the lower die 12 in the die-opening direction (the vertical direction in FIG. 3) adjacent to the side of the sprue 22 in the lower die 12. In other words, as a result of inserting the temperature sensor 26 into the mounting hole 30, the temperature sensor 26 is located where the molten metal 5 solidifies later than at cavities 14, 18. [0024]
As shown in FIG. 4, the support portion 26b fitted in the large diameter portion 30b permits no movement of the protective metal fitting 28 mounted to the lower die 12, so that it cannot be inserted further inward of the die 11 from the position shown in the drawing. The protective metal fitting 28 and the lower die 12 are made of the same material. In the first embodiment, alloy tool steel (SKD) for hot dies is employed.
9

[0025]
The length of the protective metal fitting 28, fitted in the mounting hole 30 together with the support portion 26b, is so designed that a temperature detecting section 28a or the top end of the protective metal fitting 28 protrudes into the runner 21. The temperature detecting section 28a is formed, having an outside diameter gradually smaller toward the top end, as shown in FIG. 4. In other words, the temperature detecting section 28a is formed with a draft angle or taper.
[0026]
In the first embodiment, the temperature detecting section 28a has a dome-shaped tip portion 28b that, is convex upward, to which each top end of two types of conductor 29a, 29b of the thermocouple 29 is welded. To be more specific, each top end of the conductors 29a, 29b passing the through hole 27 faces the opening of the tip portion 28b, in order to be welded together to block the opening using a welding electrode made of common material, alloy tool steel (SKD) for hot dies. The welded opening is then ground into a dome-shape.
[0027]
The well-known, typical alumel-chromel thermocouple 29 is used. It includes the two types of conductor 29a, 29b which conduct each other by welding to the tip portion 28b. Providing the thermocouple 29 in this manner allows the temperature sensor 26 to detect the temperature of the molten metal 5 which comes into contact with the tip portion 28b (where the thermocouple 29 is welded) of the protective metal fitting 28 (protective portion 26a).
[0028]
The two conductors 29a, 29b running through the protective portion 26a to the support portion 26b are lead outside of the lower die 12. They are connected to the controller 4 through the interior of a stainless duct 31 welded to the support portion 2 6b. In the temperature sensor 26 of the first embodiment, refractory insulating powder 27 is filled around the conductors 23a, 23b in the through hole 27. As the refractory insulating
10

powder 32, there may be magnesia (MgO) used for a glow plug of diesel engines, for example. [0029]
The controller 4 includes a molten metal temperature controller 33; a die temperature controller 34; a pressurization pressure controller 35; and a casting condition setter 36, as shown in FIG. 1.
The molten metal temperature controller 33 controls the temperature of the heater of the furnace 2 so as to heat the molten metal 5 in the crucible 8 at a predetermined temperature. The casting condition setter 36, which will be described later, determines the temperature of the molten metal 5 for each die used. [0030]
The die temperature controller 34 controls the temperatures of the heater and the cooling device in the die 3 so as to heat the die 3 at a predetermined temperature. The casting condition setter 36 determines the temperature of each die 3 used.
The pressurization pressure controller 35 switches on/off the pressurization device 10, while controlling the amount of gas to be supplied from the pressurization device 10 so as to make the feed rate of the molten metal 5 from the crucible 8 into the die 3 equal to a predetermined rate. The casting condition setter 36 determines the predetermined feed rate for each die used.
[0031]
By the casting condition setter 36, data related to the casting conditions, such as the die and molten metal temperatures, the pressurization and solidification times, and the feed rate of the molten metal 5, in accordance with each die used for the casting process, are sent to the molten metal temperature controller 33, the die temperature controller 34 and the pressurization pressure controller 35. The casting condition setter 36 outputs start/stop signals for the pressurization pressure controller 35 to start/stop
11

pressurizing the molten metal 5 at the respective predetermined timings. The casting condition setter 36 also outputs die-opening/clamping signals for the drive unit 13 to move the upper die 11 up/down respectively at the predetermined timings.
[0032]
Of these start/stop signals and die-clamping/opening signals, the stop and die-opening signals are sent when the temperature detected with the temperature sensor 26 reaches predetermined temperatures Tl, T2, respectively (See FIG. 6) The temperature Tl is optimum for completing pressurization of the molten metal 5, and so predetermined that there is no flowability of the molten metal 5 in the product part, the runner part, and the upper part of the sprue due to the solidification therein while the flowability of the molten metal 5 remains on the stalk 9 side from the upper part of the sprue.
[0033]
In other words, the temperature Tl is predetermined to be the maximum value at which the molten metal 5 only on the stalk 9 side below the upper part of the sprue flows down toward the crucible 8 side even if the pressurization device 10 stops pressurization. As shown in FIG. 3, in the first embodiment, the temperature Tl is so predetermined that the upper portion of the filter 23 can remain in the casting. The temperature T2, lower than the temperature Tl, is optimum for opening the die, and predetermined to be the maximum value at which the molten metal 5 solidifies enough not to have changed casting shape and dimension at die opening. [0034]
The casting condition setter 36 of the first embodiment is designed to produce non-defective products even if it is impossible for the temperature sensor 26 to detect the temperatures Tl, T2 due to some malfunction. In other words, the casting condition setter 36 is designed to determine the timings to complete the pressurization of the molten metal 5
12

and to open the die based on the times (pressurization and solidification times), instead of the temperature detected by the temperature sensor 26, for failure of the temperature sensor 26.
[0035]
To be more detailed, the casting condition setter 36 is designed to complete the pressurization of the molten metal 5 when the predetermined pressurization time has elapsed since the start of the pressurization of the molten metal 5 in the case that the temperature sensor 26 is a defective product or has some malfunction. The casting condition setter 36 is also designed to open the die when the predetermined solidification time has elapsed since the completion of the pressurization of the molten metal 5. [0036]
The pressurization time refers to a time period from the point in time when a supply of the molten metal 5 starts to the point in time when a solidifying region of the molten metal 5 expands to the sprue 22. This pressurization time is obtained by calculation, in accordance with the type of die 3 used, based on the temperature of the die 3 at the start of supplying the molten metal 5, and the temperature of the molten metal 5 in the crucible 8. The solidification time refers to a period required for the casting inside of the die 3 to solidify enough not to easily deform after the completion of the pressurization of the molten metal 5. This solidification time is obtained by calculation, depending on the type of die 3, based on the temperature of the die 3 at the completion of the pressurization of the molten metal 5. These pressurization and solidification times may be stored in a memory (not shown) as a map in advance and read from the memory as needed. [0037]
The aforementioned operation of the casting machine 1 are next described in conjunction with the further detailed configuration of the controller 4 with reference to FIGs. 5 and 6. Here, only one operation cycle (one shot) of the casting
13

work, which is repeatedly performed, is described. It is therefore assumed that the casting conditions for each die 3 have been already inputted in the casting condition setter 36, and the temperatures of the die 3 and molten metal 5 have already reached the targeted casting temperature. Inputs of the casting conditions are achieved by inputting a predetermined number given to an execution program for each die 3. [0038]
The casting work of the casting machine 1 with the die 3 clamped is started by, for example, turning the start switch (not shown) ON. When the start switch is turned ON, the casting condition setter first determines whether or not the current temperatures of the die 3 and the molten metal 5 fall within a range for producing non-defective products, as shown in the step S1 of FIG. 5. The range for producing non-defective products refers to a temperature range within which the casting can be a non-defective product, which is predetermined for each die. If NO or the aforementioned temperatures fall out of the range for producing non-defective products, the process goes to the step S2 and performs an alarm process in which the casting condition setter 36 gives an operator notice of the abnormal temperatures. This results in stopping the casting operations. [0039]
If YES, the casting condition setter 36 calculates the pressurization time of the molten metal 5 (the step S3) which is essential for executing the casting program to be used in the case the temperature sensor 26 fails to function. The casting condition setter 36 then sends the start signal to the pressurization pressure controller 35 together with the data for the feed rate of the molten metal 5 in the step S4. The start signal sent to the pressurization pressure' controller 35 in this manner causes the pressurization device 10 to supply inert gas into the furnace 2, and the pressurized molten metal 5 is supplied from the stalk 9 through the sprue cup 24, the sprue 22 and the filter into the die 3. Part of the molten metal 5 filling the cavities 14, 18 first solidifies in the product
14

part 25 within the cavities 14, 18. A solidifying region of the molten metal 5 expands from the runner 21 down to the sprue 22 with the lapse of time. In addition, when the pressurization device 10 starts the pressurization as described above, a timer (not shown) also starts simultaneously.
[0040]
After that, the casting condition setter uses the temperature sensor 2 in the lower die 12 to detect the temperature of the molten metal 13 in the runner 9 in the step S5. As shown in FIG. 6, the temperature detected with the temperature sensor 26 sharply increases after the start of casting (after the start of supplying the molten metal 5) , then remains unchanged (with the molten metal 5 flowing in the runner 21) for a certain period of time, and then gradually decreases. In the step S6, the casting condition setter 36 compares the maximum temperature detected with the temperature sensor 26 with a predetermined temperature range. If the maximum temperature falls within the predetermined temperature range, the casting condition setter 36 determines that the temperature sensor 26 works properly. In contrast, if the maximum temperature falls out of the predetermined temperature range, it determines that the temperature sensor 26 does not work properly (is in an abnormal condition)..
[0041]
In the case it is determined that the temperature sensor 26 is in an abnormal condition in the step S6, when the elapsed time indicated by the timer reaches the pressurization time obtained in the step S3, the casting condition setter 36 sends the stop signal to the pressurization pressure controller 35. Then the pressurization pressure controller 35 receives the stop signal, which causes the pressurization device 10 to stop the inert gas supply, thereby completing the pressurization of the molten metal 5 (the step S7) . Approximately at the same time when the supply of the molten metal 5 is stopped, the casting condition setter 36 calculates the solidification time based on the current temperature of the die 3 (the step S8) .
15

[0042]
After the stop of supplying the molten metal 5 in the step S7, the unsolidified metal 5 in the die flows from the sprue 22 through the sprue cup 24 and the stalk 9 to drop back into the crucible 8 . The molten metal 5 remaining in the die 3 (with no flowability) further solidifies with increased hardness as the result of no heat supply (the step S9) . When the pressurization of the molten metal 5 is completed, the timer (not shown) starts.
Then, the casting condition setter 36 sends the die-opening signal to the drive unit 13 after the time indicated by the timer reaches the solidification time. Then the drive unit 13 receives the die-opening signal, which causes the upper die 11 to move up to open the die (the step 10 to the step 11) . [0043]
If YES in the step S6 or it is determined that the temperature sensor 26 works properly, the casting condition setter 36 uses the temperature sensor 26 to detect the temperature of the molten metal 5 in the runner 21 in the step S12. The temperature detected with the temperature sensor 26 varies as shown in FIG. 6. After reaching the maximum temperature, it gradually decreases as the molten metal 5 further solidifies. The casting condition setter 36 sends the stop signal to the pressurization pressure controller 35 when the temperature detected with the temperature sensor 26 decreases to the predetermined temperature Tl (the step S13) . Then the pressurization pressure controller 35 receives the stop signal, which causes the pressurization device 10 to stop the inert gas supply, thereby completing the pressurization of the molten metal 5 (the step S14). [0044]
When the pressurization of the molten metal 5 is completed, the unsolidified metal 5 drops back into the crucible 8 while the molten metal 5 having no flowability remains in the die 3. This remaining molten metal 5 further solidifies since its temperature further decreases as the result of no heat
16

supply. The casting condition setter 36 uses the temperature sensor 26 to constantly detect the temperature of the molten metal 5 in the runner part as shown in the steps S15, S16. When the temperature of the molten metal 5 detected with the temperature sensor 26 decreases to the predetermined temperature T2, the casting condition setter 36 determines the completion of the solidification and sends the die-opening signal to the drive unit 13. [0045]
The drive unit 13 receives the die-opening signal in this manner, which causes the upper die 11 to move up to open the die (the step Sll). One cycle of the casting work ends. At the die-opening, in either case that the casting moves up with the upper die 11, or the casting remains in the lower die 12, the temperature detecting section 25 of the temperature sensor 2 can be easily removed from the casting when it is separated from the lower die 12. This is because the temperature detecting section 28a of the temperature sensor 26 is formed with a draft angle or taper. As described above, the protective metal fitting 28 including the temperature detecting section 28a and the thermocouple welding part are made of the same material as the die, providing excellent wear resistance. This therefore prevents them from being worn out by castings. [0046]
The low-pressure casting machine 1 configured as previously described uses the temperature sensor 26 to directly detect the temperature of the molten metal 5 adjacent to the boarder between the sprue 22 and the runner 21 (temperature of the molten metal 5, which solidifies later than at the cavities 14, 18). Therefore, the low-pressure casting machine 1 can complete the pressurization of the molten metal 5 or open the die when the temperature of the casting reaches the optimum temperature. It is thus possible to minimize the pressurization time for the molten metal 5 and the solidification time, from the completion of the pressurization to die-opening, to a period required for the casting to be a
17

non-defective product. This therefore further improves productivity with the reduced casting cycle time.
[0047]
The temperature detection section 28a of the temperature sensor 26 used in the casting machine 1 of the first embodiment has a draft angle or taper, and protrudes from the inner wall face of the lower die 12 into the die 3 in the die-opening direction. The temperature sensor 26 thus can detect the temperature of the molten metal 5 in the runner 21 located adjacent to the product part 25, and allows easy removal of the temperature detecting section 28a from the casting after the casting process. Accordingly, the temperature sensor 26 prevents the temperature detecting section 28a from being broken when the die is opened or the casting is separated from the die while detecting the temperature of the molten metal 5 with high accuracy.
[0048]
In the casting machine 1 of the first embodiment, a region adjacent to the boarder between the sprue 22 and the runner 21 in the lower die 12 is located outside of the product part of the casting 25. The molten metal 5, filling this region, thus has a temperature approximately equal to the temperature of the molten metal in the product part 25, and therefore solidifies generally in the same manner as the product part 25 slightly later than at the product part 25. The casting machine 1 of the first embodiment uses the temperature sensor 26 to detect the temperature of the molten metal 5 located in the region adjacent to the boarder between the sprue 22 and the runner 21. This means that the temperature detected with the temperature sensor 26 is equivalent to the temperature of the product part of the casting 25. Therefore, the timings to complete the pressurization of the molten metal 5 and to open the die can be determined with high accuracy. In other words, in the casting machine 1, there is no need to extend the supply and solidification times to adjust the difference in temperatures between the temperature detecting section and the product part
18

25, as is the conventional case. Accordingly, the cycle time can be reduced. Moreover, in the casting machine 1, no trace of the temperature sensor 26 remains on the product part 25, achieving production of a quality casting.
[0049]
The casting machine 1 of the first embodiment directly detects the temperature of the molten metal 5, and determines the timings to complete the pressurization of the molten metal 5 and to open the die based on this detected temperature. This ensures that the pressurization of the molten metal 5 is completed and the die is opened in the timeliest manner in accordance with the conditions of the casting, even if there are variations in temperature of the die 3 at the start of the casting process . Thus, there is no need for the casting machine 1 to unnecessarily extend or shorten the pressurization and solidification times for the molten metal 5, or the supply and solidification times can be minimized to a period required for the casting to be a non-defective product. This further improves the productivity.
[0050]
(Second Embodiment)
A temperature sensor may be located at a sprue, as shown in FIG. 7. The figure is a sectional view, showing another example of installing the temperature sensor at the sprue of the low-pressure casting machine. In the figure, components, which are the same as or equivalent to those described with reference to FIGs. 1 through 6, are denoted by their respective common reference numerals, and the detailed descriptions are not repeated as appropriate .
A temperature sensor 26 shown in FIG. 7 is mounted to a lower die 12 and a temperature detecting section 28a protrudes to a sprue 22 from its side. At the sprue 22 in the lower die 12 is formed a projection 41 for the purpose of avoiding molten metal 5, which flows up within the sprue 22, from pressuring the temperature detecting section 28a.
[0051]
19

The projection 41 is so formed as to cause part of the peripheral wall of the sprue 22 to protrude inward. In the second embodiment, in order to reduce the resistance caused when molten metal 5 flows up within the sprue 22 as soon as possible, the end edge on the protruding side of the projection 41 is inclined so as to be gradually closer to the center of the sprue 22 toward the upper side. A contact portion between the projection 41 and the temperature detecting section 28a has a structure in which the lower half of the temperature detecting section 28a of circular cross-section is fitted into a recess 41a formed on the upper face of the projection 41, so that only the upper half of the temperature detecting section 28a is exposed.
The temperature detecting section 28a of the temperature sensor 26 faces inside of the sprue 22, which allows the temperature sensor 26 to directly detect the temperature of the molten metal 5 in the sprue 22. Therefore, the second embodiment can also achieve the same effects as obtained in the first embodiment. [0052] (Third Embodiment)
An embodiment of the present invention applied to a gravity casting machine is described in details with reference to FIGs. 8A, 8B through 11.
FIGs. 8A and 8B, and 9A and 9B illustrate dies used for the gravity casting machine, in which FIGs. 8A and 9A are cross sectional plan views and FIGs. 8B and 9B are vertical sectional views. FIG. 10 is a flowchart for the purpose of explaining the casting operation. FIG. 11 is a graph, illustrating how the molten metal temperature changes.
A gravity casting die 51, as shown in FIGs. 8A and 8B, and 9A and 9B, includes a first die 52 and a second die 53 formed so as to open in the horizontal direction, as well as cavities 54, 55 and risers 56, 57 above the cavities. The first die 52 and the second die 53 are mounted to a die drive unit (not shown) by which the dies are clamped and opened.
20

In the die 51 shown in FIG. 8A and 8B, the molten metal 5 is supplied from the risers 56, 57 into the cavities 54, 55. The die 51 shown in FIG. 9A and 9B has a sprue 58 formed with an upward opening on the side of the risers 56, 57. A structure is employed in which the molten metal 5 is supplied from the sprue 58 through a runner 59 to the bottom of the cavities 54, 55. These dies 51 each have a temperature sensor 26 provided in the risers 56, 57. [0054]
The temperature sensor 26 is an equivalent to what is used for the first embodiment, and mounted to the first die 52 with a temperature detecting section 28a protruding from the inner wall face of the riser 56 in the die-opening direction. In other words, also in this case, the temperature sensor 26 is located at a position where the molten metal 5 solidifies later than at the cavities 54, 55. As is the case with the die 51 of FIGs . 9A and 9B, in which the sprue 58 and the runner 59 are used to supply the molten metal 5 to the bottom of the cavities 54, 55, the sprue 58 may be provided with the temperature sensor 26, as shown by a phantom line in FIG. 9B. [0055]
The gravity casting machine with the die 51 configured as described above is controlled by a controller (not shown) in a manner shown in FIG. 10. To be more specific, the controller determines whether or not the current temperatures of the die
51 and the molten metal 5 fall within a range for producing
non-defective products in the step P1 in the flowchart of FIG.
10. The range for producing non-defective products refers to
a temperature range within which the casting can be a
non-defective product, which is predetermined for each die. If
NO or the aforementioned temperatures fall out of the range for
producing non-defective products, the process goes to the step
52 and performs an alarm process in which the controller gives
an operator notice of the abnormal temperatures. This results
in stopping the casting operations.
[0056]
21

If YES, the gravity casting machine uses a molten metal supply device (not shown) or the like to supply the molten metal 5 (pouring) to fill the die 51 (the step P3) . At the pouring, the controller 4 calculates the solidification time of the molten metal 5 which is essential for executing the casting program to be used in the case the temperature sensor 26 fails to function. At the same time, the timer starts.
[0057]
As mentioned above, after the supply of the molten metal 5 into the die 51, the controller uses the temperature sensor 26 to detect the temperature of the molten metal 5 in the risers 56, 57 or the sprue 58, as shown in the step P4 . The temperature detected with the temperature sensor 26 sharply increases after the casting process start (pouring start), then remains unchanged for a certain time period, and then gradually decreases, as shown in FIG. 11. After that, the controller 4 determines that the temperature sensor 26 works properly if the maximum temperature detected with the temperature sensor 26 falls within a predetermined temperature range in the step P5. In contrast, if the maximum temperature falls out of the predetermined temperature range, it determines that the temperature sensor 26 does not work properly (is in an abnormal condition).
[0058]
If it is determined that the temperature sensor 26 is in the abnormal condition in the step P5, the controller is in standby until the elapsed time indicated by the timer reaches the solidification time obtained in the step P3 (the step P6) and then sends a die-opening signal to the die drive unit. The die drive unit then receives the die-opening signal in this manner, which causes the die to open (the step P7).
If YES in the step P5 or the temperature sensor 26 works properly, the controller uses the temperature sensor 26 to detect the temperature of the molten metal 5 in the step P8 .
[0059] The temperature detected with the temperature sensor 26
22

varies as shown in FIG. 11. After reaching the maximum temperature, it decreases as the molten metal 5 further solidifies. When the temperature detected with the temperature sensor 26 decreases to the predetermined temperature T3 (the step P9), the controller uses the die drive unit to open the die (the step P7). The temperature T3 is predetermined to be the maximum value at which the molten metal 5 solidifies enough not to have changed casting shape and dimension at die opening. In this way, the die is opened, which results in completion of one cycle of the casting work. The temperature detecting section 28a of the temperature sensor 26 can be easily removed from the casting when it is separated from the first die after the casting process, since the temperature detecting section 28a is formed with a draft angle or taper. [0060]
Thus, the gravity casting machine with the die 51 of the second embodiment uses the temperature sensor 26 to directly detect the temperature of the molten metal 5, and determines the timing to open the die based on this detected temperature. This ensures that the die 51 is opened in the timeliest manner in accordance with the conditions of the casting, even if there are variations in temperature of the die 51 at the start of the casting process.
Therefore, in this gravity casting machine, there is no need to unnecessarily extend or shorten the solidification time for the molten metal 5, or the solidification time can be minimized to a period required for the casting to be a non-defective product. This further improves the productivity. Industrial Applicability [0061]
The present invention can be applied to a casting machine for casing parts, such as cylinder heads of vehicle engines, marine engines or other general-purpose engines.
23

Claims
[1] A casting machine including a temperature sensor for detecting a temperature to be used to control operation timing, wherein the temperature sensor is located at a position where solidification occurs later than at a cavity of a die, such that a temperature detecting section of the temperature sensor comes in direct contact with molten metal.
[2] The casting machine according to Claim 1, wherein the operation timing is the timing when molten metal supply is stopped.
[3] The casting machine according to Claim 1, wherein the operation timing is the timing when the die is opened.
[4] The casting machine according to Claim 1,
wherein the temperature detection section of the
temperature sensor has a draft angle or taper, and protrudes
into the die from the inner wall face thereof in a die-opening
direction.
[5] The casting machine according to Claim 4, wherein the casting machine is a low-pressure casting machine, and the temperature detection section of the temperature sensor is located at a position adjacent to a boarder between a sprue and a runner in a lower die.
[6] The casting machine according to Claim 1, wherein the casting machine is a low-pressure casting machine, and the temperature detection section of the temperature sensor is located at a position adjacent to a boarder between a sprue and a runner in a lower die.
[7] The casting machine according to Claim 6, wherein a controller is provided for completing the pressurization of the molten metal when the temperature of the molten metal detected with the temperature sensor reaches a predetermined temperature, and for opening the die when the temperature of the molten metal detected with the temperature sensor reaches a predetermined temperature.
[8] The casting machine according to Claim 1, wherein the casting machine is a gravity casting machine,
24

and the temperature detection section of the temperature sensor is provided in a riser of the die, and wherein a controller is provided for opening the die when the temperature of the molten metal detected with the temperature sensor reaches a predetermined temperature.
25
[9] The casting machine according to Claim 1, wherein the casting machine is a gravity casting machine, and the temperature detection section of the temperature sensor is provided at a sprue of the die, and wherein a controller is provided for opening the die when the temperature of the molten metal detected with the temperature sensor reaches a predetermined temperature.
A temperature sensor (26) is located in a lower die (12) at
a position (runner 21) where molten metal (5) solidifies later
than at cavities (14, 18). A temperature detecting section
(28a) of the temperature sensor (26) comes in direct contact
with the molten metal (5).

A temperature sensor (26) is located in a lower die (12) at
a position (runner 21) where molten metal (5) solidifies later
than at cavities (14, 18). A temperature detecting section
(28a) of the temperature sensor (26) comes in direct contact
with the molten metal (5).

Documents:

01951-kolnp-2006 abstract.pdf

01951-kolnp-2006 assingment.pdf

01951-kolnp-2006 claims.pdf

01951-kolnp-2006 correspondence other.pdf

01951-kolnp-2006 description(complete).pdf

01951-kolnp-2006 drwings.pdf

01951-kolnp-2006 form 1.pdf

01951-kolnp-2006 form 2.pdf

01951-kolnp-2006 form 3.pdf

01951-kolnp-2006 form 5.pdf

01951-kolnp-2006 international publication.pdf

01951-kolnp-2006 international serch authority.pdf

01951-kolnp-2006 pct form.pdf

01951-kolnp-2006 priority document.pdf

01951-kolnp-2006-correspondence others-1.1.pdf

01951-kolnp-2006-correspondence-1.2.pdf

01951-kolnp-2006-form-18.pdf

1951-KOLNP-2006-(02-05-2012)-CORRESPONDENCE.pdf

1951-KOLNP-2006-(29-12-2011)-ABSTRACT.pdf

1951-KOLNP-2006-(29-12-2011)-AMANDED CLAIMS.pdf

1951-KOLNP-2006-(29-12-2011)-CORRESPONDENCE.pdf

1951-KOLNP-2006-(29-12-2011)-DESCRIPTION (COMPLETE).pdf

1951-KOLNP-2006-(29-12-2011)-DRAWINGS.pdf

1951-KOLNP-2006-(29-12-2011)-FORM-1.pdf

1951-KOLNP-2006-(29-12-2011)-FORM-2.pdf

1951-KOLNP-2006-(29-12-2011)-FORM-3.pdf

1951-KOLNP-2006-(29-12-2011)-OTHERS.pdf

1951-KOLNP-2006-(30-12-2011)-CORRESPONDENCE.tif

1951-KOLNP-2006-(30-12-2011)-OTHER PATENT DOCUMENT.pdf

1951-KOLNP-2006-CORRESPONDENCE 1.1.pdf

1951-KOLNP-2006-TRANSLATED COPY OF PRIORITY DOCUMENT.pdf

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Patent Number

254685

Indian Patent Application Number

1951/KOLNP/2006

PG Journal Number

49/2012

Publication Date

07-Dec-2012

Grant Date

05-Dec-2012

Date of Filing

12-Jul-2006

Name of Patentee

YAMAHA HATSUDOKI KABUSHIKI KAISHA

Applicant Address

2500 SHINGAI, IWATA-SHI, SHIZUOKA 4388501

Inventors:

#	Inventor's Name	Inventor's Address
1	HIROSHI YOSHII	C/O. YAMAHA HATSUDOKI KABUSHIKI KAISHA 2500 SHINGAI,IWATA-SHI, SHIZUOKA 4388501
2	TAKASHI ODA	C/o.YAMAHA HATSUDOKI KABUSHIKI KAISHA 2500 SHINGAI, IWATA-SHI, SHIZUOKA 4388501

PCT International Classification Number

B22D2/00; B22D18/04

PCT International Application Number

PCT/JP 05/000684

PCT International Filing date

2005-01-20

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2004-012873	2004-01-21	Japan