Title of Invention

A TOOL FOR METAL CUTTING MACHINING OF VALUE SEATS

Abstract

A tool for metal cutting machining of valve seats in cylinder heads of internal combustion engines, the tool comprising: a cutter tip having at least one geometrically defined cutting edge; two supporting regions in the tool for supporting the cutter tip, against which the cutter tip rests, and the supporting regions are oriented with respect to each other at an angle a, the supporting regions also being so oriented that a line bisecting the angle between the supporting regions runs essentially perpendicular to an active one of the cutting edges, which is the edge that removes metal chips from the surface in the opening.

Full Text

FORM 2 THE PATENTS ACT, 1970 (39 Of 1970) COMPLETE SPECIFICATION (See Section 10) A TOOL FOR METAL CUTTING MACHINING OF VALUE SEATS MAPAL FABRIK FUR PRAZISIONSWERKZEUGE Dr. Kress KG of OBERE BAHNSTRASSE 13, 73431 AALEN, GERMANY, GERMAN Company The following specification particularly describes the nature of the invention and the manner in which it is to be performed : - ORIGINAL 572/NUM/2003 03/06/2003 GRANTED 10-12-2004 Tool for the metal-cutting machining of valve seats The invention relates to a tool for the metal-cutting machining of valve seats in cylinder heads of internal combustion engines, . and to a method for the metal-cutting machining of valve seats in cylinder heads of internal combustion engines. Tqols and methods of the type under discussion here are known. The tools have a cutter tip which comprises at least one geometrically defined cutting edge with the aid of which chips can be removed from the valve seat either by the tool being set i,n rotation with respect to a fixed workpiece or the workpiece being set in rotation with respect to a fixed tool. As a rule, the former of the two cases is realized. The valve seat has a first annular surface which encloses, with an imaginary central axis of the annular surface, a first angle of inclination of, for example, approximately 45°. This first annular surface essentially determines the gas tightness of the valve, it is adjoined firstly by a second annular surface with in angle of inclin.ilion of approximately 15° and secondly by a thhird annular surface! with an angle of the incl i ria lion of app rox i ma tetly 75 During the machining of the valve seat, the tool, is displaced axial ly along the common central axis of the annular surfaces until the cutter tip is [00616454.1} in engagement with the valve seat and, for example, the first annular surface is machined. The machining therefore takes place by means of a movement of the tool in the direction of the valve axis, which coincides with the central.axis of the annular surface. The machining is referred to as a valve-cutting process. Use is preferably made of tools which can be used to machine both the valve seat and the valve guide, i.e. which have a cutter tip for machining the valve seat and a reamer for machining the valve guide. As a result, the central axis of the valve seat is aligned very precisely with the central axis of the valve guide, which contributes to the valve being well sealed. The valve seat in cylinder heads of internal combustion engines is generally realized by valve seat rings which consist of very hard, wear-resistant sintered materials, which means that the machining is very complex and cubical boron nitride (CBN) generally has to be used, which is very expensive. In addition, very exacting requirements are made of the quality in order to ensure the "gas tightness". Even a small amount of wear to the cutting edge leads to the permissible tolerances being exceeded. Overall, it turns out that the costs for machining the valve seat are very high. It is therefore the object of the invention to provide a tool of the type mentioned at the beginning which does not have t hi. s di sad vantage . To achieve this object, a tool having a cutter tip which has at least one geometrically define cutting edge. It is distinguished by the cutter tip resting on two supporting regions which are arranged at an angle a and the angle-bisecting line of which runs essentially perpendicularly with respect to the cutting edge which removes chips from the valve seat. The arrangement of the supporting surfaces gives rise, as it were, to an inverted V guide for the cutter tip, with the result that the latter is held in a very stable manner in the main body of the tool. That is to say, the cutter tip is anchored on the tool in such a manner that the cutter tip hardly vibrates at all during the machining of a valve seat. It has been found that vibrations cause a relatively pronounced increase in the wear of the cutting edge and that, conversely, if the cutter tip is anchored in the manner such that it hardly vibrates, the wear of the active cutting edge, i.e. the cutting edge which removes chips from the valve seat, can be significantly reduced. It is also the object of the invention to provide a method which does not have the disadvantages mentioned. To achieve this object, a method is proposed which distinguished by the cutter tip of the tool not needing to be reset or adjusted if a cutting edge becomes worn. This results in a substantial simplification of the method and therefore also to less expensive solutions. According to a tool for metal cutting machining of valve seats in cylinder heads of internal combustion engines, the tool comprising: a cutter tip having at least one geometrically defined cutting edge; two supporting regions in the tool for supporting the cutter tip, against which the cutter tip rests, and the supporting regions are oriented with respect to each other at an angle a, the supporting regions also being so oriented that a line bisecting the angle between the supporting regions runs essentially perpendicular to an active one of the cutting edges, which is the edge that removes metal chips from the surface in the opening. A method for metal cutting machining of valve seats in cylinder heads of internal combustion engines comprising operating a tool as discussed above at the valve seats, wherein the cutter tip is not required to be reset or adjusted when a respective active cutting edge thereof becomes worn. The method further comprising displacing the tool in the direction of a central axis of the annular valve seat during machining of the valve seat. Figure 8 shows a schematic diagram of a valve seal, with a valve The illustration according to Figure 1 shows a valve seat machining tool, i.e. a tool 1 which is used for machining valve seats in cylinder heads of internal combustion engines. On the left-hand side of the tool, a fastening stem 3 can be seen which is surrounded by an annular plane surface 5. The fastening stem 3 is Used for coupling the tool 1 to a machine tool, the plane surface 5 ensuring that the tool 1 is exactly aligned. The tool 1 may also be coupled to a machine tool, in a different manner. On that side of the tool 1 which lies opposite the fastening stem 3, a cutter tip 7' can be seen which has a geometrically defined cutting edge 9. The latter is used to remove chips from a valve seat 11 which is part of a valve seat ring 13 which is inserted into a cylinder head (not illustrated hero) of an internal combustion engine. The cutter tip 7 is -fastened to Che main body 17 of the tool. 1 by means of a clamping claw 15. The clamping claw 15 is tightened with a clamping screw 19 in such a manner that a clamping lip 21 comes t.o rest on the front side 21 of the cutter tip 7, which side is also referred to as the cutter breast plate. (00616151 . 1 ) At that end 25 of the tool 1 which lies opposite the fastening stem 3, a point of separation can be provided at which a tool for machining the valve guide, in particular a reamer, can be.fitted. The region in which the cutter tip 7 is fitted to the main body 17 of the tool 1 is illustrated on an enlarged scale in Figure 2. Identical parts are provided with the same reference numbers, so that reference can be made to the description for Figure 1. From the enlarged illustration according to Figure 2, which shows the cutter tip 7 in plan view, a first supporting region 27 and a second supporting region 2 9 can be seen on which the cutter tip 7 not only rests, but is also pressed against the supporting regions 27 and 29 by the clamping claw 15. In order to improve the holding forces of the clamping lip 21 of the clamping claw 15, clamping notches 31 which are of V-shaped design as seen in cross section - are made in the front side 23 of the cutter tip 7, so that the clamping lip 21 not only presses the cutter tip 7 against the supporting regions 27 and 29, but also against a supporting surface (not. visible here). The supporting regions 27 and 2 9 are arranged at an angle a, specifically in such a manner that the angle-bisecting line {00616454.1} 33 is essentially perpendicular to the active cutting edge 9 with which chips are removed from the Valve seat 11. In the exemplary embodiment illustrated here, the cutter tip 7 is designed as an indexable tip. It can be rotated about an imaginary axis which is perpendicular to the front side 23 of the cutter tip 7,with the result that, if the active cutting edge 9 becomes worn, a further cutting edge 9 of the cutter tip 7 is available for machining the valve seat 11. The cutter tip 7 is designed here as a hexagon. It therefore has six cutting edges 9 separated in each case from an adjacent cutting edge 9 by a rounded corner 35. The cutting edge 9 is formed in each case by the outer edge region of the cutter tip 7 which lies between two adjacent corners 35. The cutter tip 7 of the tool 1 has to be ground in a very precise manner and has to have absolutely straight cutting edges 9. In the exemplary embodiment illustrated here, it is therefore possible to turn the cutter plate 7 six times and thus to make available six cutting edges 9 for the machining of a valve seat. Accordingly, three clamping notches 11 are provided arranged in a star-shaped manner on the front side 23 of the cutter tip 7. The cutting edges are adjoined in each case by a chip-guiding surface 37 which is bounded by chip-guiding steps 39 which are arranged at a distance from the cutting edge and against which the chips removed by tho (00616154.1] cutting edge 9 strike and become broken. The design of a cutter tip 7 as illustrated here is' known in principle. However, a difference here is that i.t is not actually the corners 35 which are used as cutting edges in the metal-cutting machining of a workpiecc, but rather the regions arranged between said corners. Accordingly, Figure 2 also illustrates the cutting edge 9 machining the valve seat 11 with a region lying between the corners 35. In this case, the active cutting edge 9 is not as Long as the outer edge of the cutter tip 7, which edge lies between the corners 35. Figure 3 shows the cutter tip 7 in the installed position, as also illustrated in Figures 1 and 2, but with the clamping claw removed. Identical parts are provided with the same reference numbers, so that reference is made to this extent to the preceding description. It can be seen from. Figure 3 that the cutter tip 7 is inserted into the main body 17 of the tool 1 in such a manner that it rests with at least two sides on supporting regions 27 and 29. It is also clear that clearances 45 which are arranged in the region of the corners 35 of the cutter tip 7 are provided in the region of the mai.n surface 41 of a recess 43 which holds the cutter plate 7 and the clamping claw 15. This ensures that the rear side lying opposite the front side 23 of the cutter tip 7 rests flat on the main surface 41. It is clear from the illustration according to Figure 3 thai, a hole 47 which pierces the main surface 41 is provided in the {00616454.1} main body 17, and the clamping screw 19 (not illustrated here) with which the clamping claw 15 is anchored to the main body 17 engages in said hole. For clarification purposes, Figure 4 shows the detail of the tool 1 (which detail is illustrated in Figure 3) without the cutter tip 7, so that the bearing surfaces 27 and 29 and the main surface 41 can be clearly seen. It can be seen from Figure 4 that the main surface 41 can also have a step 42, i.e. that the region in which the clamping claw 15 comes to lie is somewhat higher than the direct supporting region A for the cutter tip 7. Figure 5 shows a cross section along the line V-V shown in Figure 3. The cutter tip 7, which is arranged on the main surface 41, specially in the supporting region A of the recess 43 of the main body 17 of the tool 1, can clearly be seen. The clamping notches 31 which are made in the front side 23 of the cutter tip 7 and in which the clamping lip 21 (not illustrated here) of the clamping claw 15 engages can also be seen. The sectional illustration also shows the second supporting region 29 on which the cutter plate 7 rests. The latter is of virtually trapezoidal design: the main surface of the trapezium is formed by the front side 23 of the cutter tip 7 and the upper side is formed by the rear side 49 of the cutter tip 7, which side lies opposite the front side 23. The rear .side 49 is placed on on the main surface 41. the side surfaces of the culler tip 7 are formedd by thanks of the cutter tip 7. In Figure 5 at the top, a cutter 9 is illustrated and, lying opposite it, a cutter 9'. The latter is adjoined by a first flank region 51 which has a certain angle of inclination The angle of Inclination of the first flank region it may be greater than that of the second flank region 53, so that the first flank region 51 does not rest on the supporting region 29 and the cutting edges, here the cutting edge 9', resting on the supporting region cannot be damaged. In order to ensure a defined contact of the cutter tip 7 against the supporting region 29, in the vicinity of the main surface 41, a "clearance" 55 is provided, i.e. a gap between the side surface 57 of the recess 43 and the side surface 59 of the cutter plate 7. The clearance can be realized by the side surface 57 of the recess 43 running away from the cutter tip 7 in the direction of the main surface 41 or by the cutter tip 7 being somewhat abraded in the region of. the clearance 55. {0061615'11) It is crucial for the side surface 59 of the cutter tip 7 to rest on the main body 17 of the tool 1 in the supporting region 29. Here, in the exemplary embodiment illustrated in Figure 5, the second supporting region 29 is formed directly by the main body 17 of the tool 1. Figure 6 shows a modified exemplary embodiment of a tool 1, specifically again in section along the line V-V which is illustrated in Figure 3. Identical parts are provided with the same reference numbers, so that reference is made to the description for the preceding figures. The sole difference over the tool 1 which is illustrated in Figure 5 is that inserts 61 which form the supporting regions 27 and 29 are placed into the main body 17, or are at least provided here. In this case, it is possible to provide inserts which are of more or less rectangular design or else to insert a pin into the main body 17, said pin being provided in each case in the region of the supporting regions and being used to support the cutter tip 7. The material of the inserts is preferably harder than that of the main' body 17. Insert 61 made of metal carbide and/or ceramic and/or CBN are particularly preferred. In Figures 5 and 6, a dashed line indicates the fact that the cutter tip is provided with a layer a of culiead boton nitride (CBN), the thickness of which is preferably selected in such a manner that this layer does not come into contact with the supporting regions 27 and 29. The main body of the Cutter tip 7 preferably consists of metal carbide. Figure 7 once again shows the cutter tip 7, v/hich is secured by a clamping claw 15, with a modified embodiment of the clamping lip 21. Tools of the type under discussion here are, as a rule, provided with a coolant/lubricant supply, with the aid of which the active cutter 9, i.e. the cutter which is in the prpcess of removing chips from a valve seat 11, is charged with the coolant/lubricant in order to avoid the cutter becoming too hot, in particular in order to ensure that the temperature of the cutting edge is as uniform as possible. In the exemplary embodiment illustrated in Figure 7, the clamping claw 15, more precisely its clamping lip 21, has a coolant outlet 63 from which the coolant emerges in the direction of the active cutter 9. The coolant outlet 63 is elongate here, in parti cu1ar is rectangu1ar, and proferabIy runs parallel to the active cutter 9. The length of the coolant outlet 63 is selected in such a manner that the active cutter 9 is charged over its entire width with the coolant/Lubricant. 100616151. ! } In Figure 7, the forces which occur during the machining of a valve seat are referred to in greater detail. In this case, the cutting force FS is indicated by a first arrow and the two supporting forces which are applied by the supporting regions 27 and 29 are indicated by arrows which are designated by Fl and F2. Figure 8 shows a schematic diagram of a valve seat 11 with a valve 65. The valve seat is realized in the region of the valve seat ring 13. On its inside, it has three annular regions which run concentrically with respect to an imaginary central axis 67 which also constitutes the central axis of a valve guide 69. The valve guide may comprise a cylindrical insert 71 which consists of a hardened, wear-resistant material, and, like the valve seat ring, is inserted into the cylinder head of an internal combustion engine. In the region of the valve seat, the valve closes an inlet or outlet 75 of the internal combustion engine which comprises the cylinder head 73. Three annular regions of the valve seat are indicated by three lines indicated on the right and left of the central axis 67. A first annular region encloses with the central axis 67 an angle of, for example, approximately 45°, which is indicated by a first: line of. Situated above the first annular region is a second annular region which has a wa11 which tapers conically from the bottom upward and encloses (00616454.1) with the central axis 67 an angle of approximately. 75°, which is indicated by a line L2. Situated below the first annular region is a third annular region which tapers conically .from. the bottom upward and the wall of which encloses with the central axis 67 an angle of 15°. This third annular region which is identified by this angle is indicated by the line L3. In the case of the valve seats described here, it is of particular concern for the gas tightness of the combustion chamber, which is situated below the valve 65, to be ensured. This has a particularly pronounced effect on the consumption and power of the internal combustion engine. As indicated in Figure 8, the valve seat 11 is preferably formed by a valve seat ring 13 which is pressed or shrunk into the cylinder head'73 and consists of a very hard, wear-resistant material. (00616451.1) The requirements placed on the quality of the sealing surface of the valve seat 11, i.e. here placed essentially on the first annular surface, are very exacting in, respect of surface quality and evenness. In addition, The angle with respect to the central axis 67, which angle is indicated by the line L1, has to be manufactured within very exacting tolerances. It can be concluded from this that the cutter 9 of the cutter tip 7 has to be ground very precisely and has to have absolutely straight cutting edges. In addition, the cutter tip has to be held in a very exact and stable tip seat in order to ensure that the cutter tip, and therefore the active cutter, are exactly aligned with respect to the valve seat. This is of crucial importance particularly if very hard materials have to be machined and, for example, polycrystalline cubical boron nitride is used as the material for the cutter. Particularly in the case of this brittle material, no vibrations must occur at all, since otherwise the service lives of the cutters are poor. During the machining of the valve seat, i.e. during the process of cutting the valve seat, the tool (not illustrated in Figure 8) is moved along the central axis 67 until the cutter tip comes into engagement with the valve seat 11 and the valve seat ring 13. In order to produce the annular regions having different angles of inclination, tools with cutters inclined at different angles are used. Of course, during the machining of the valve seat, the valve 65 is (00616454.1} removed, so that the tool can be introduced into the interior of the valve seat rinq 13 As stated, a reamer can be inserted into the end 25 of a too] according to Figure 1, said reamer machining the inner •surface Of the valve guide 69 and guiding the tool. If saic tool is displaced along the contral axis 67 to machines the valve guide 69, the cutter tip 7 finally comes int The following is to be stated with regard to the operation o the tool: The tool 1 is set into rotation for the machining of valv seats 11, which, as a rule, are part of a valve seat ring 13 and is introduced into the opening in the valve seat, i.e. i displaced axially in the direction of the central axis of th annular valve seat, until the cutter tip 7 removes chips frc the valve seat 11. The machining process is also reterred L as the process of cutting the valve seat. The valve seats c valve seat rings which are to be machined consist of ver hard sintered material:;, with the result that corresponding] hard cutter tips 7 have to be used, preferably cutter tip {00616454.:i) which include a layer S of cubical boron nitride (CBN). This material has the property of being very sensitive to vibrations. If vibrations occur during the machining of a . valve seat 11, this results in a very pronounced degree of wear, which leads to interruptions to the machining process because the cutter tip has to be exchanged, or, as in the case of the tools described here, has at least to be rotated in order to bring a new cutter of the cutter tip, which is designed as an indexable tip, into engagement with the valve seat. In the case of the tools 1 described here, the cutter tip 7 can be anchored very securely in the main body 17 of the tool 1 because it is supported on two supporting regions 27 and 29 which are arranged at an angle a with respect to each other, specifically in such a manner that the angle-bisecting line 33 is virtually perpendicular to the valve seat 11 which is to be machined and to the active cutter 9. The cutter tip 7 is pushed onto the supporting regions 27 and 29 firstly by the clamping claw 15 and secondly by the cutting forces FS, which are illustrated in Figure 7. The supporting regions 27 and 29, which are arranged at an angle a, supply the supporting forces Fl and F2, thus resulting, as it were, in an inverted V guide for the cutter tip 7. The forces pressing the cutter tip 7 against the supporting regions 27 and 29 have to be very high in particular if the (006.16454.1) supporting regions are provided with inserts 61 consisting oi a material which is harder than that of the main body 17 of the tool 1. Inserts 61 of metal carbide and/or ceramic and/or CBN are preferably used, so that very high press-on forces can be realized without any deformations occurring in the supporting regions 27 and 29 and thus resulting in the cutter tip 7 being misaligned. The inverted V guide thus enables the cutter tip to be held and secured very exactly at a predeterminable angle in the main body 17 of the tool 1. It is clear that in the case of the tool 1 illustrated here, i.e. because of the cutter tip 7 which is designed as an indexable tip and because of the exact positioning of the cutter tip 7 by means of the supporting surfaces 27 and 29, resetting or adjusting devices which may weaken the tool 1 are not required at all. The space which is gained may also allow the use of larger clamping screws in conjunction with the clamping claw 15, so that the clamping forces may also be increased. Since the cutter tip 7 needs merely to be rotated' should the active cutter 9 become worn, it is in no way disadvantageous for the tool 1 that an ,adjustingi is omitted. The inverted V guide of the cutter tip is designed, as Figure 7, in particular, shows clearly, in such a manner that the cutter tip is stabilized by the cutting forces is in the main body {0063.6451.1} 17 of the tool 1, namely is pressed against, the supporting regions 27 and 29. If the supporting regions 27 and 29 are provided with inserts 61, the latter may be of essentially rectangular design,,. which can readily be seen from Figure 6. However, it is also possible for a pin, against which the cutter plate 7 is supported, to be inserted in each case into the main body 17 of the tool 1. However, a sheet-like design is preferred because then higher press-on forces can be supported without any problem. It is clear from Figures 5 and 6 that a layer of the cutter tip 7 consists of CBN and is preferably selected in such a manner that said layer extends merely over a first flank region 51. This avoids the very brittle material being acted upon by lateral forces, which could possibly result in damage. Since the main body of the cutter tip 7 preferably consists of metal carbide, very high supporting forces can be built up in the supporting regions 27 and 29 without this resulting in any disadvantageous deformation of the cutter tip 7 whatsoever. From the explanations to the figures, it is clear that clearances are provided at critical points in order to avoid point-like or line-like loads. Clearances 45 are thus provided firstly in the region of the corners 35 of the cutter tip 7 and secondly in the transition region between (00616454.1) the side surface 59 of the cutter: tip 7 and its read side 4 9. This last-mentioned clearance 55 may, as explained above, be realized in a different manner, namely by an offset of the side surface 59 of the cutter tip 7 or of the side surface 57 of the recess 4 3 in which the cutter tip 7 is accommodated. Finally, it has also been found that a targeted coolant/lubricant feed is advantageous in particular in the case of cutter plates with a layer S of CBN. The cutting material CBN is sensitive to thermal shock and sensitive to different temperatures of the cutting edge 9. Owing to the special coolant/lubricant feed through the clamping claw 15, very effective cooling of the active cutter 9, which removes chips from the valve seat 11, can be achieved, in particular if a coolant outlet 63 is provided in the clamping claw 15, said outlet being elongate and designed in such a manner that the active cutter 9 is charged with coolant in the region of the machined valve seat 11. It is therefore possible to match the jet of coolant to the width of the cutter and to ensure uniform cooling by the coolant outlet 63 running parallel to the active cutter 9. From the explanations regarding the tool, it is clear that in the case of a method for machining valve seats in cylinder heads of internal combustion engines with a tool which comprises at least one cutter tip having a geometrically defined cutter, a simp]ifi cation of the method occurs by the fact that an adjustment of the tool, should the active cutter (00616154.1) We Claim: 1. A tool for metal cutting machining of valve seats in cylinder heads of internal combustion engines, the tool comprising: a cutter tip having at least one geometrically defined cutting edge; two supporting regions in the tool for supporting the cutter tip, against which the cutter tip rests, and the supporting regions are oriented with respect to each other at an angle a, the supporting regions also being so oriented that a line bisecting the angle between the supporting regions runs essentially perpendicular to an active one of the cutting edges, which is the edge that removes metal chips from the surface in the opening. 2. The tool as claimed in claim 1, wherein the supporting regions are formed by supporting surfaces. 3. The tool as claimed in claims 1 or 2, wherein the tool includes a main body and the supporting regions are formed in the main body. 4. The tool as claimed in claim 1, wherein the tool has a main body and respective inserts in the main body are positioned for defining the supporting regions. 5. The tool as claimed in claim 4, wherein the inserts are essentially rectangular cross section shaped elements. 6. The tool as claimed in claim 4, where in the insertare pin-shaped elements. > 7. The tool as claimed in claim 4, wherein the inserts are comprised of a material of a greater hardness than the hardness of the main body. 8. The tool as claimed in claim 7, wherein the inserts are of a material selected from at least one of the group consisting of metal carbide, ceramic and cubical boron nitride. 9. The tool as claimed in claim 1, wherein clearances are provided at least in regions of the supporting regions. 10. The tool as claimed in claim 1, further comprising a feed for coolant /lubricant for feeding coolant / lubricant to the cutting edge. 11. The tool as claimed in claim 10, wherein the coolant/lubricant feed takes place through a clamping claw, which holds the cutting tip. 12. The tool as claimed in claim 11, wherein the feed for coolant / lubricant includes an elongate coolant outlet in the claw; the outlet runs essentially parallel to the active cutter edge. 13. The tool as claimed in claim 1, wherein the cutter tip is an indexable tip. 14. The tool as claimed in claim 1, wherein the cutter tip is hexagonally shaped. 15. The tool as claimed in claim 1, wherein the cutter tip is tipped with cubical boron nitride. 16. The tool as claimed in claim 1, wherein the cutter tip has an external layer of cubical boron nitride for cutting purposes. 17.The tool as claimed in claim 1, wherein the cutter tip has a flank, which includes regions of different angles of inclination. 18. A method for metal cutting machining of valve seats in cylinder heads of internal combustion engines comprising operating a tool as claimed in claim 1 to 17 at the valve seats, wherein the cutter tip is not required to be reset or adjusted when a respective active cutting edge thereof becomes worn. 19 the methodofclaim 20, further comprising displacing the tool in the direction of a central axis of the annular valve seat during machining of the valve seat. Dated this 2nd day of June, 2003. HIRAL CHNDRAKANT JOSHI AGENT FOR APPLICANT

Documents:

572-mum-2003-cancelled pages(10-12-2004).pdf

572-mum-2003-claims (granted)- (10-12-2004).pdf

572-mum-2003-claims(granted)-(10-12-2004).doc

572-mum-2003-correspondence(12-01-2005).pdf

572-MUM-2003-CORRESPONDENCE(27-9-2012).pdf

572-MUM-2003-CORRESPONDENCE(31-5-2011).pdf

572-mum-2003-correspondence(ipo)-(24-05-2007).pdf

572-mum-2003-drawing (10-12-2004).pdf

572-mum-2003-form 1(03-06-2003).pdf

572-mum-2003-form 19(15-12-2003).pdf

572-mum-2003-form 2 (granted)- (10-12-2004).pdf

572-mum-2003-form 2(granted)-(10-12-2004).doc

572-MUM-2003-FORM 26(27-9-2012).pdf

572-MUM-2003-FORM 26(31-5-2011).pdf

572-mum-2003-form 3(03-06-2003).pdf

572-mum-2003-form 5(03-06-2003).pdf

572-mum-2003-power of attorney(03-06-2003).pdf

572-mum-2003-power of attorney(16-12-2004).pdf

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