Title of Invention

A METHOD OF PREVENTING CAR THEFTS AND DEVICE THEREFOR.

Abstract

A method of preventing car thefts by means of a device comprises a key cylinder (28) and a controller (16), a key (12) insertable in said key cylinder (13) for switching on a main switch (17), and a built-in transponder (15) in said key (12) for identifying an ID code of said key (12) when said key (12) is inserted in said key cylinder (13), starting of the engine (11) being allowed when the ID code identified by said transponder (15) coincides with an ID code which has been registered in said controller (16), said method comprising the steps of: reading an ID code of a key (12) accessing to said key cylinder (28) ; determining whether or not the ID code read has been registered in a memory (21) and outpuffing an ignition permission signal when the code has been already registered ; holding said ignition permission signal in a holding circuit (34) until said main switch (17) is switched off ; and controlling the engine (114) by an engine controlling means (19, 24) according to said ignition permission signal held in said holding circuit (34), said engine controlling means (19,24) comprising an ignition circuit (24) ; wherein said ignition permission signal is directly input to said ignition circuit (24) from said holding circuit (34).

Full Text

BACKGROUND OF THE INVENTION This invention relates to a system and device for preventing car thefts and more particularly to an improved method and apparatus for locking a motor vehicle. Many motor vehicles now employ locking systems that include a key which is not only keyed to a tumbler but which also carries a built-in transponder which works with a receiver mounted on the vehicle and normally as a part of the locking mechanism so as to contain a specific ID code. When the key is inserted into the locked cylinder, the transponder transmits a signal to the device and its ID is checked. If the proper ID is not registered, then it is impossible for the user to start the engine even if the key can be turned in the lock cylinder and thus, thefts are prevented. Although these types of locking mechanisms are extremely valuable in preventing thefts, because of the fact that they must continually recognize the presence of the key in the ignition system in an electrical manner, electrical malfunctions or noise in the electrical system can cause the triggering mechanism to disconnect. Even if a resetting function is included, during the interrupted time interval, the engine will stop running and this can be not only uncomfortable but has some potential risk. It is, therefore, a principal object to this invention to provide a locking system of this type wherein as long as an appropriate key has been switched on and remains in the ignition system, the engine will not stop running unless and until that key is positively shut off. SUMMARY OF THE INVENTION This invention is adapted to be embodied in a method of preventing vehicle thefts and key locking system for a vehicle that comprises a key cylinder and controller that are mounted on the vehicle and a key which is insertable into the key cylinder for switching on a main switch for activating a prime mover of the vehicle. The key has a built-in transponder containing an ID code of the key to be sensed when the key is inserted into the key cylinder by the controller The operation of the prime mover is permitted only when the ID code detected by the transponder coincides with an ID code, which has been registered in the controller. In accordance with a method for performing the invention, power for operating the prime is held in an on condition until the recognized key is shut off regardless of the condition of the controller. In accordance with a key locking system of the type described, power operating the prime is held in an on condition until the recognized key is shut off regardless of the condition of the controller. Accordingly, the present invention provides a method of preventing car thefts by means of a device comprising a key cylinder and a controller mounted on a vehicle body, a key insertable in said key cylinder for switching on a main switch, and a built-in transponder in said key for identifying an ID code of said key when said key is inserted in said key cylinder, starting of the engine being allowed when the ID code identified by said transponder coincides with an ID code which has been registered in said controller, said method comprising the steps of : reading an ID code of a key accessing to said key cylinder; determining whether or not the ID code read has been registered in a memory and outputting an ignition permission signal when the code has been already registered , holding said ignition permission signal in a holding circuit until said main switch is switched off ; and controlling the engine by an engine controlling means according to said ignition permission signal held in said holding circuit, said engine controlling means comprising an ignition circuit; wherein said ignition permission signal is directly input to said ignition circuit from said holding circuit. The present invention also provides a device for preventing car thefts comprising a key cylinder and a controller mounted on a vehicle body, a key insertable in said key cylinder for switching on a main switch, and a built-in transponder in said key for identifying an ID code of said key when said key is inserted in said key cylinder, starting of the engine being allowed when the ID code identified by said transponder coincides with an ID code which has been registered in said controller, said device being characterized by : a memory in which the ID code of said key is registered ; an ID reading circuit for reading an ID code of a key accessing to said key cylinder; an ID determination section for determining whether or not the ID code read by said ID reading circuit has been registered in said memory and for outputting an ignition permission signal when the code has been already registered ; a holding circuit for holding said ignition permission signal until said main switch is switched off; and an engine controlling means for controlling the engine according to said ignition permission signal held in said holding circuit, said engine controlling means comprising an ignition circuit ; wherein said ignition permission signal is directly input to the ignition circuit from said holding circuit. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure 1 is a partially schematic view showing the main components of a vehicle having a locking system operated and constructed in accordance with the invention. Figure 2 is a view, in part similar to Figure 1, but showing in more detail the relationship between the key, the key cylinder and the controller. Figure 3 is a view showing the flow routine and association with the various keys used in the system illustrating how the mechanism is originally set at the factory and how a . new registration of keys can be accomplished. Figure 4 is a flow diagram showing the operation in accordance with normal ordinary use. Figure 5 is a flow diagram showing how the registration of a master key is "accomplished in accordance with the normal registration practice as well as the resetting of the master key. Figure 6 is a flow diagram showing how the device re-registered a key for use as a master key when the key cylinder is replaced. Figure 7 is a view showing the procedure for maintaining the prime mover in operation even in the event of an electrical problem in the theft deterrent system. Figures 8 and 9 are a table showing how the various operating conditions and description of their operation are followed in accordance with the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION Referring now in detail to the drawings and initially to Figures 1 and 2, a key system incorporating the invention and operated in accordance with an embodiment of the invention is illustrated schematically in these figures. In Figure 1, the system is shown schematically in combination with a vehicle which is powered by a prime mover which is depicted schematically as an internal combustion engine, indicated generally by the reference numeral 11 but can include other prime movers such as electric motors, fuel cells, etc. The vehicle may be a land vehicle such as a car or motorcycle or any other type of land, water or air vehicle. Basically, the operation of the prime mover 11 is controlled under a function of a locking system which includes a key, indicated by the reference numeral 12, and a key cylinder, indicated generally by the reference numeral 13. The key 12 basically includes a normally keyed portion 14 and a base portion in which a transponder 15 is mounted that has a built in ID code. The latter description will describe a number of keys such as a master key, sub-keys, and an all clear key, which have certain functions and which are utilized in accordance with the invention to permit and simplify the resetting a new master or sub-key either when the master key is replaced or the key cylinder is replaced. The key cylinder 13 in addition to having a normal tumbler section operated by the keying portion 14 of the key 12 also includes an ID signal reception device in the form of an antenna that sends and receives signals from the transponder 15 of the inserted key 12. This antenna then outputs its signal of the reading of the key ID code to a controller, indicted generally by the reference numeral 16, and which has a number of associated components including. One of these components is associaited with a main switch 17 that is operated by the key cylinder 13 upon the turning of the appropriate key therein in manners which will be described. The ID code is transmitted from the antenna coil of the key cylinder 13 to an ID reading circuit, indicated by the reference numeral 18, which outputs its signal to a CPU unit 19. The CPU unit 19 determines the results of the comparison of the ID code of the inserted key with certain codes that have been memorized and other functions as set forth hereinafter. The CPU 19 also receives information from an Electronically Erasable Programmable Read Only Memory (EEPROM) indicated by the reference numeral 21, which stores certain ID codes in a manner, which will be described. Based upon the functioning of the rotation of the key 12 in the key cylinder 13, a power source circuit 22 is turned on to permit the main switch 17 to be activated and transmit a source of electrical power from a battery 23 to the controller 16. This also permits a signal to be sent from the CPU 19 to an ignition circuit 24 if the appropriate key has been utilized so as to permit energerization of a spark plug 25 of the engine 11. If an electrical motor is utilized as the prime mover, the ignition circuit 24 will comprise a switch for transmitting electrical power to the electric motor for its operation, for example by way of a pulse width modulation device, as a way of example. Additionally, the device may include a display section 26 that is mounted in an appropriate position on the associated vehicle for viewing by the operator and which displays certain information, as will become hereinafter described. These may comprise vehicle operating conditions such as speed and/or security conditions. Referring now to Figure 2, this figure shows in more detail the units associated with the CPU and the controllers for controlling the operation of the prime mover 11. The antenna of the key cylinder 13 appears in this figure and is identified by the reference numeral 27, which, as aforenoted, outputs its signal to the ID reading circuit 18 of the controller 16. This output is then transmitted to the CPU 19 which includes an ID determination circuit 28 which decodes the ID signal from the transponder 15 to the antenna 27, an ID erasing section 29 which functions to erase all ID"s from the volatile memory of the CPU 19, an ID registration section 31 which establishes a new ID registrations as recognized and approved IDs and an timer section 32, for a purpose which will be described. The power source circuit 22 includes a self-holding section 33, which maintains the power source on after the key operated main switch 17 is closed and then reopened after a predetermined time interval. As seen in this figure, the main switch 17 may be actually incorporated physically in the key cylinder 13. The controller 16 also includes a holding circuit 34 that functions to hold the ignition circuit 24 in an enabled mode for a time period after until the main switch 17 is opened after switching off the recognized key. This prevents uneven running which might otherwise occur in the event of electrical noise or if the source of current fluctuates. The EEPROM 21 is indicated at the memory in this figure. It should be noted that the ignition circuit 24 includes not only a device for permitting the operation of the prime mover 11 to be initiated assuming the right key is inserted and switched on, but also has the function of prohibiting starting or operation of the prime mover 11 if the appropriate key has not been inserted and turned. Referring now to Figure 3, this shows the various types of keys which are employed and the way in which they function both during initial registration of a master key and user registration of sub-keys as well as re-registration in the event a key is lost or in the event the key cylinder 13 is replaced or a new master key must be utilized for any reason. It has been previously mentioned that: there are all clear keys, master keys and sub- keys and each of these is shown with the all clear key being indicated by the reference numeral 12-1. This master key has a transponder but is not keyed so that it will not be able to turn in the key cylinder 13. A line registration master key 12-2 is also provided that in this embodiment, serves the function of both being capable of registered as a master key and also can be used for erasing or registering sub-keys. Also, this key can be utilized to erase all IDs upon lock replacement, as will be described. This key is keyed as at 14 so that it can be rotated in the key cylinder 13 in a manner, which will be described. The user registration keys include the master key 12-2 as previously described and two sub-keys (1 & 2) indicated at 12-3 and 12-4. These keys 12-2, 12-3 and 12-4 all have the same key sections 14 but have different IDs in their respective transponders. Also, the sub-keys 12-3 and 12-4 do not have the capability of erasing data. The last portion of the upper part of this figure when proceeding from left to right, shows a situation where there is a re-registration of a key which has been lost and this lost key is the sub-key 12-4 and replaced by a new sub-key 12-5. The sub-key 12-5 is like all other sub-keys in its functioning and as previously described. Now referring to the bottom portion of this figure, the ignition unit memory is shown which includes, as noted in Figure 2, the main ignition unit 24 and the memory section 21 that includes the EEPROM having the re-writable section and a fixed non-erasable section. The function of the all clear key is to clear all of the master and sub IDs maintained and this is operated by merely inserting the all clear key 12-1 into the ignition key cylinder 13. When this is done, all of the erasable memory erased while the all clear fixed data is maintained in place. The master key 12-2 is intended to be the master key retained by the owned and its insertion into the key cylinder 13 in the manner, which will be described hereinafter, causes the master key code to be memorized in the re-writable memory. Then, after this key has been inserted, then the sub-keys 1 and 2 (12-3 and 12-4) are inserted into the key cylinder 13 in the manner, which will be described, these keys are registered in the re-writable memory. In the re-registration of a key, which may be done after a key is lost, the master key is first inserted so to clear the memory of the previously registered sub-keys and then all sub- keys to be used can be registered. This will include re-registration of the sub-key 1 (12-3) and registration of a new sub-key 2 (12-5). The various control routines will now be described starting with Figure 4, which depicts the operation in ordinary use. It is assumed that the operator or owned of the vehicle will maintain the main key separately and will use one of the sub-keys for normal operation. Thus, the operation is as follows in that at the step SI, the main switch is switched on with a sub-key such as the sub-key 12-2 or 12-3. When this is done, the power source circuit 22 is energized at S2 and outputs electrically energy to the ID reading circuit 18 and the antenna of the key cylinder 13. The transponder is then energized and outputs its ID code, which is compared with the registered ID codes in the CPU 19 at the step S3. Then the comparison is made at the step S4 and if the inserted key has a registered key, then ignition is allowed by the ignition circuit 24 at the step S5 and the engine is started at the step S6 so as to be running. At this time the immobilizer section 35 of the display 26 (Figure 1) is not activated or illuminated If, however, at the step S4 it is determined that the inserted key number is not equal to a registered key number or it is not possible to read an ID of the inserted key, within 5seconds after the switch is turned on, the program at the step S7 determines if this time limit has expired. If it has not, the program repeats and the immobilizer section 35 of the display 26 is constantly illuminated. If, however, the time of 5 seconds has elapsed, and the significance of this time will become apparent later, then the program moves to the step S8 where ignition is prohibited and the step S9 where engine starting is disabled and the immobilizer display is flashed for a short time such as one second. Thus, in normal operation the system makes a comparison to confirm that the inserted and switched key is a registered key and if so, ignition and prime mover operation is initiated. If not within a predetermined time period such as the 5-second example given, it is impossible to start the prime mover 11 and the operator is warned. Figure 5 shows the control routine when the new master key is programmed in at the factory as indicated in the second view of Figure 3 or when a re-registration occurs at shown in the right hand of this figure. The first portion of the routine is the line registration of a new vehicle and it begins at the step S11 where the main switch is turned on with a master key. This is done after the all- clear key has been inserted and removed as noted in discussing the routine of Figure 3. When this master key 12-2 is placed into the key cylinder 13 and the master switch is turned on, at the step S12, the ID of the new key is read in by the ED reading circuit. The display 35 is not illuminated at this time. At this time, the master data registers this new key in the EEPROM 21 and specifically in the fixed memory thereof at the step S13. Then, ignition or starting of the prime mover is enabled at the step S14. It may be that ignition is not possible immediately and several re-registrations may be made This is in part due to the necessity to initially charge the transponder 15 of the master key. Thus the display 35 is flashed slowly until registration is completed and then the display 35 is turned off. Then the main switch is turned off at the step S16 and this generally completes the original registration. However, there is a brief time delay when the holding circuit 33 (Figure 22) maintains the supply of power. This is done for a period of time such as 10 seconds after the main switch is turned off. Thus, the unit power source is kept in a holding state. However, this time normally runs out under initial registration without any further registration. If, however, it is desired to register a new key, then after the main switch is turned off at the step S16 and the program moves to the step 17 to run the timer and determine if the 10- second time delay has elapsed. If it is, the program is shut off at the step S18 and no new registration can be made. If, however, at the step S17 it is determined that the main switch is still on and the 10- second run has not yet ran, the program moves to the step S19 to initiate the possibility for a re-registration to correct a mis-registration of the wrong main key. This is just one example of when a mis-registration can be taken care of. Then, at the step S19 if an all clear key such as the key 12-2 is inserted before the time of 10 seconds has ran out, the program moves to the step S20 so as to read the ID of the inserted key. If the ID of the inserted key is one that is pre-programmed into the fixed data, then at the step S21 all registered IDs are erased. The program then moves to the step S22 where the all clear key is drawn out and the program moves back to the step S11 so as to permit the setting of a new main key. Thus, this procedure is utilized when there is a mis- registration of the main key on the original line registration. The routine for resetting the master key when the key cylinder 13 is replaced will now be described by particular reference to Figure 6. The program begins at the step S31 which is initiated when the main switch is switched on with a new key that is not registered. Then at the step S32 the ID of the inserted key is read by receiving the transmission signal from the transponder 15 to the communication circuit and the ID reading circuit 18. Then at the step S33 the ID of the inserted key is compared with the ID of the registered key or keys. The program then goes into a holding pattern where the timer sets a time interval of 5 seconds for after the main switch has been turned at the step S34 and an indication on the display 26 is given to indicate that the operation display section is illuminated continuously. If the 5-second interval has not passed, the program repeats back to the step S32. If, however, at the step S34 it is determined that the 5 second delay has run, then the program moves to the step S35 to prevent operation of the prime mover and the flashing light is turned on a relatively slow interval, such as 2 seconds. Then, if the main switch is turned off and the new key has been removed, at the step S36, the program moves to the step S37 to determine if a 10 second time interval has elapsed after the main switch 17 has been turned off. If it has been, the program moves to the step S38 and switches off the power source circuit 22. If, however, the time limit for the 10 seconds has not run out at the step S37, the program moves to the step S39 to determine if an all clear key or an old master is inserted. If it has not been, the program repeats back to the step S37 and continues until either the time limit has run and then the power is switched off at the step S38 or the insertion of a new key is again checked at the step S39. The program then moves to the step S49 if either the all-clear key or an old registered master key has been inserted where the ID of the inserted key is read in. Then the program moves to the step S41 so as to erase from the EEPROM 21 the ID codes of all registered IDs to be erased. Then, at the step S42 either the all-clear key or the old master key that has been inserted is withdrawn. Then the program moves to the step S43 where a new key to be registered is inserted. This can be one of the sub-keys. When this new key is inserted, the program moves to the step S44 wherein the ID of the new key is read. The program then moves to the step S45 so as to register the new key as the master key. The program then moves to the step S46 wherein ignition is allowed and subsequently at the step S47 the main switch will be turned off and the program stops. As has been previously noted, a condition may occur when electrically noise generated during vehicle running can cause the computer 19 to reset and restart the operation from the beginning. Also, this may occur due to temporary interruptions or variations in source voltage. In other words, if these conditions occur, it is necessary for the computer to again determine or verify the ID code of the key 12. This can result in engine misfiring for a short time period and/or a reduction in engine speed. Regardless, it will give an uncomfortable feeling to the vehicle and its occupants. Therefore, the holding circuit 34 is provided which maintains the ignition circuit 24 in an enabled condition until the inserted key is switched off due to its rotation in the locking cylinder. This routine may be seen in Figure 7, which is another flow diagram showing the operation. This program begins at the step S51 when the initial power source is turned on by switching on the main power source circuit 22. Then, if the ID reading circuit 18 indicates that the read ID is that which has been registered, the program makes this comparison at the step S52 and assuming that the key] is a correct one, the ignition circuit is enabled at the step S53. This signal is then held by the holding circuit 34 at the step S54. The program then moves to normal engine control at the step S55. During the normal engine control, the device continues to monitor the condition of the main switch 17 and as long as the key 12 is left in its on condition at determined at the step S56, the program continues to repeat. If, however, it is found that the key has been switched off at the step S56, turning off of the holding circuit 34 begins at the step S57. However, before this stopping is completed, the program moves to the step S58 to determine whether a predetermined time has elapsed after the switch has been turned off. This time can be set at any desired value. If, during this time, it is desired to reset the ID, this can be done in the manner previously described at the step S59. The power is then turned off at the step S60. and the engine is basically stopped at this time. The tables of Figures 8 and 9 show the various conditions of operation and summarize what has been previously stated. Since these figures are really self-explanatory, it is not believed necessary to repeat their descriptions and those skilled in the art will readily understand how these procedures are accomplished and what is done during the procedures. Thus, from the foregoing description, it should be readily apparent that a system has been disclosed and described that permits the setting of a new key and the register if all keys have been not initially registered or the updating of a system wherein the master switch is replaced and avoiding the necessity of creating a new key or modifying an existing key so as to match the ID of the new switch. Also, this permits the correction of mis-registrations without complicated procedures. Furthermore the system avoids the likelihood of uneven prime mover operation due to electrical noise or variations in the available electrical power. Of course, the foregoing description is that of preferred embodiments of the invention and various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims. WE CLAIM : 1. A method of preventing car thefts by means of a device comprising a key cylinder and a controller mounted on a vehicle body, a key insertable in said key cylinder for switching on a main switch, and a built-in transponder in said key for identifying an ID code of said key when said key is inserted in said key cylinder, starting of the engine being allowed when the ID code identified by said transponder coincides with an ID code which has been registered in said controller, said method comprising the steps of: reading an ID code of a key accessing to said key cylinder; determining whether or not the ID code read has been registered in a memory and outputting an ignition permission signal when the code has been already registered ; holding said ignition permission signal in a holding circuit until said main switch is switched off; and controlling the engine by an engine controlling means according to said ignition permission signal held in said holding circuit, said engine controlling means comprising an ignition circuit; wherein said ignition permission signal is directly input to said ignition circuit from said holding circuit. 2. A method as claimed in claim 1, wherein ID codes of more than one key are registered in said memory. 3. A method as claimed in claim 2, wherein at least one of said registered ID codes is an ID code of a sub-key. 4. A method as claimed in claim 2 or 3, wherein one of said registered ID codes is an ID code of a master key which can be used to erase registered ID codes of sub- keys. 5. A method as claimed in any one of claims 2 to 4, wherein one of said registered ID codes is an ID code of an all-clear key which can be used to erase registered ID codes other than that of said all-clear key. 6. A device for preventing car thefts comprising a key cylinder and a controller mounted on a vehicle body, a key insertable in said key cylinder for switching on a main switch, and a built-in transponder in said key for identifying an ID code of said key when said key is inserted in said key cylinder, starting of the engine being allowed when the ID code identified by said transponder coincides with an ID code which has been registered in said controller, said device being characterized by : a memory in which the ID code of said key is registered ; an ID reading circuit for reading an ID code of a key accessing to said key cylinder; an ID determination section for determining whether or not the ID code read by said ID reading circuit has been registered in said memory and for outputting an ignition permission signal when the code has been already registered ; a holding circuit for holding said ignition permission signal until said main switch is switched off; and an engine controlling means for controlling the engine according to said ignition permission signal held in said holding circuit, said engine controlling means comprising an ignition circuit; wherein said ignition permission signal is directly input to the ignition circuit (18) from said holding circuit. 7. A device as claimed in claim 6, wherein ID codes of more than one key (34) are registered in said memory. 8. A device as claimed in claim 7, wherein at least one of said registered ID codes is an ID code of a sub-key. 9. A device a claimed in claim 7 or 8, wherein one of said registered ID codes is an ID code of a master key which can be used to erase registered ID codes of sub-keys. 10. A device as claimed in any one of claims 7 to 9, wherein said one of said registered ID codes is an ID code of an all-clear key which can be used to erase registered ID codes other than that of said all-clear key. A method of preventing car thefts by means of a device comprises a key cylinder (28) and a controller (16), a key (12) insertable in said key cylinder (13) for switching on a main switch (17), and a built-in transponder (15) in said key (12) for identifying an ID code of said key (12) when said key (12) is inserted in said key cylinder (13), starting of the engine (11) being allowed when the ID code identified by said transponder (15) coincides with an ID code which has been registered in said controller (16), said method comprising the steps of: reading an ID code of a key (12) accessing to said key cylinder (28) ; determining whether or not the ID code read has been registered in a memory (21) and outputting an ignition permission signal when the code has been already registered ; holding said ignition permission signal in a holding circuit (34) until said main switch (17) is switched off ; and controlling the engine (114) by an engine controlling means (19, 24) according to said ignition permission signal held in said holding circuit (34), said engine controlling means (19, 24) comprising an ignition circuit (24) ; wherein said ignition permission signal is directly input to said ignition circuit (24) from said holding circuit (34).

Documents:

508-cal-2000-granted-abstract.pdf

508-cal-2000-granted-claims.pdf

508-cal-2000-granted-correspondence.pdf

508-cal-2000-granted-description (complete).pdf

508-cal-2000-granted-drawings.pdf

508-cal-2000-granted-form 1.pdf

508-cal-2000-granted-form 18.pdf

508-cal-2000-granted-form 2.pdf

508-cal-2000-granted-form 3.pdf

508-cal-2000-granted-form 5.pdf

508-cal-2000-granted-gpa.pdf

508-cal-2000-granted-letter patent.pdf

508-cal-2000-granted-reply to examination report.pdf

508-cal-2000-granted-specification.pdf

508-cal-2000-granted-translated copy of priority document.pdf