Source: http://www.google.com/patents/US4758835?ie=ISO-8859-1&dq=5,687,325
Timestamp: 2014-07-14 08:01:39
Document Index: 595812407

Matched Legal Cases: ['art 36', 'art 36', 'art 42', 'art 50', 'arts 43', 'art 43', 'art 64', 'arts 67']

Patent US4758835 - System for the locking and/or unlocking of a security device - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsA system for the locking and/or unlocking of a security device, particularly an automobile locking device, comprising a transmitting device for transmitting coded data recording, a receiving device for receiving the coded data recording, a transmitter-end storage and a receiver-end storage for storing...http://www.google.com/patents/US4758835?utm_source=gb-gplus-sharePatent US4758835 - System for the locking and/or unlocking of a security deviceAdvanced Patent SearchPublication numberUS4758835 APublication typeGrantApplication numberUS 06/897,694Publication dateJul 19, 1988Filing dateAug 18, 1986Priority dateAug 21, 1985Fee statusLapsedAlso published asDE3529882A1, DE3680971D1, EP0212046A2, EP0212046A3, EP0212046B1Publication number06897694, 897694, US 4758835 A, US 4758835A, US-A-4758835, US4758835 A, US4758835AInventorsKlaus Rathmann, Rupert Janofske, Hans-Joachim Schroder, Heinz Allerdist, Gerhard RosslerOriginal AssigneeVdo Adolf Schindling AgExport CitationBiBTeX, EndNote, RefManPatent Citations (6), Non-Patent Citations (1), Referenced by (42), Classifications (9), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetSystem for the locking and/or unlocking of a security deviceUS 4758835 AAbstract A system for the locking and/or unlocking of a security device, particularly an automobile locking device, comprising a transmitting device for transmitting coded data recording, a receiving device for receiving the coded data recording, a transmitter-end storage and a receiver-end storage for storing codes and a comparator for comparing the received data recording with the stored data recording, a control signal being adapted to be given off to the security device from the receiving device in the event that said data agree. The receiving device has a signal generator to produce several further coded data which are stored in the transmitting device and in the receiving device and can be employed upon the subsequent use of the system. The further coded data recording may be random number and/or algorithms for changing the random numbers. The production of the further coded data recording is effected preferably upon actuation of the ignition lock.
We claim: 1. A system for the locking and/or unlocking of a security device, particularly an automobile locking device, comprisinga transmitting device for transmitting coded data; and a receiving device for receiving the coded data; first storage means in said transmitting device for storing data to be transmitted; second storage means in said receiving device for storing codes; and a comparator for comparing the data sent by said transmitting device with data stored in said second storage means, said receiving device including means for generating a control signal to activate the security device in the event that the data at said comparator is in agreement; and wherein said generating means comprises a signal generator for generating a plurality of further coded data suitable for storage in said first and said second storage means and sendable by the receiving device; and the further coded data comprises at least one random number and an algorithm, there being computers located in said transmitting device and in said receiving device for modifying the at least one random number in response to operation of said security device enabling the random number to be newly selectable for each locking operation; said system further comprising sending means located in said receiving device for sending a random number from said signal generator to said transmitting device; and accepting means located in said transmitting device for accepting the random number sent by the sending means, the computer of said transmitting device being operatively coupled to said accepting means for receiving the random number from the accepting means to provide the coded data to be transmitted by the transmitting device, the coded data transmitted by the transmitting device to the receiving device being based on a previous sending of the random number from the sending means of the receiving device to the accepting means of the transmitting device. 2. The system according to claim 1, whereinthe further coded data is composed of a plurality of random numbers. 3. The system according to claim 1, whereinthe algorithm is used for the repeated modification of a random number. 4. The system according to claim 1, whereinthe algorithm can be changed from random number to random number. 5. The system according to claim 1, whereinfor a locking of the security device, the same coded data is sent out by the transmitting device as was previously sent out for an unlocking. 6. The system according to claim 1, whereinsaid generating means generates an acknowledgement signal and wherein the deriving of the coded data by said computers to be sent out does not take place until the acknowledgement signal sent out by the receiving device is received by the transmitting device. 7. The system according to claim 1, whereinthe receiving device further comprises an acknowledgement transmitter for acknowledging coded data received from the transmitting device. 8. The system according to claim 1, whereinthe sending means is located in the immediate vicinity of an ignition lock of the vehicle and the further coded data is produced by said generating means after actuation of the ignition lock and then sent out. 9. The system according to claim 8, whereinthe further coded data is sent out after a random period of time after actuation of the ignition lock. 10. The system according to claim 1, whereinsaid computers generate a number of codes which are derived in each case from a random number by use of an algorithm, the number of codes being smaller by 1 than the number of derived codes necessary for figuring out of the algorithm and whereupon a different random number is used. 11. The system according to claim 10, wherein the use of the algorithm is a multiple use of the algorithm.
12. The system according to claim 1, whereinsaid transmitting device is located within an automobile key. 13. A method, in a system for the locking and/or unlocking of a security device, particularly an automobile locking device, comprisinga transmitting device, separate from the security device, for transmitting coded data; and a receiving device, coupled to the security device, for receiving the coded data; first storage means in said transmitting device for storing data to be transmitted; second storage means in said receiving device for storing codes; and a comparator for comparing the data sent by said transmitting device with data stored in said second storage means, said receiving device including means for generating a control signal to activate the security device in the event that the data at said comparator is in agreement; and wherein said generating means comprises a signal generator for generating a plurality of further coded data suitable for storage in said first and said second storage means and sendable by the receiving device; and the further coded data comprises at least one random number and an algorithm, there being computers located in said transmitting device and said receiving device for modifying the at least one random number; the method of securely activating a lock, comprising the steps of generating a set of random numbers at the receiving device; sending a random number from the receiving device to the transmitting device; sensing operation of a lock at the receiving device; selecting another of said random numbers of said set upon each operation of the lock by a computer at the receiving device; sending the random number to the transmitting device; updating a code with said another random number at the computers of both the transmitting and the receiving devices; and transmitting the code from the transmitting device to the receiving device. 14. The method according to claim 13 whereinsaid generating step employs an algorithm, said method including a further step of altering said algorithm is response to activation of vehicular ignition. 15. The method according to claim 14, further comprising:locating said transmitting device in an automobile key; placing said receiving device in an automobile; inserting the key in an ignition lock; and transmitting code data from said transmitting device to said receiving device while the key is in the ignition lock. Description
FIELD AND BACKGROUND OF THE INVENTION The present invention relates to a system for the locking and/or unlocking of a security device, particularly an automobile locking device, having a transmitting device for transmitting coded data recording, a receiver device for receiving the coded data recording, a storage on the transmitter end and one on the receiver end for storing codes, and a comparator for comparing the data recording received with the data recording stored, a control signal being adapted to be given to the security device from the receiving device in the event that such data recording agrees.
Devices in which coded data recording is emitted by a transmitter in order to actuate security devices are known in particular as door locks for automobile doors and they already possess a high degree of security against unauthorized opening of the car doors.
However, there is the possibility of recording the coded data recording with a receiving device during an opening process and, by subsequently transmitting this data recording, of readily opening the parked, locked car without any damage to it.
Thus there has already been proposed a control device for the locking and/or unlocking of a security device of the aforementioned type in which the receiver has a signal generator for generating further coded data recording and the further coded data recording can be stored in the storage of the receiver device and sent out by a transmitter to the receiver device, and the transmitting device has a receiver to receive the further coded data recording and the further coded data recording can be stored in the storage of the transmitting device.
SUMMARY OF THE INVENTION It is an object of the invention to create a system for the locking and/or unlocking of a security device which, with a high degree of security, prevents the unauthorized unlocking of the security device.
According to the invention, the receiver device (2) has a signal generator for generating a plurality of further coded data recording and the further coded data recording can be stored in the storages of the transmitting device (1) and receiving device (2).
By this development, the coded data recording can be changed as frequently as desired so that even in the event that the coded data recording is recorded, a subsequent unauthorized opening of the security device is prevented even if on such occasion the attempt should be made to draw conclusions as to the following data recording by recording a plurality of coded data and comparing the coded data. In this connection the changing of the code of both the receiving device and of the transmitting device takes place by itself, after it has once been introduced.
Thus in the case of a remote-controlled security device the security against unauthorized opening is considerably improved.
The production and transmission as well as the storage of the further coded data recording can preferably be turned on by a switch on the receiving device. If the switch is the ignition switch (battery terminal 15) of the vehicle, then a completely new coding is automatically effected upon each start or at a later time, this new code being stored both in the receiving device and in the transmitting device. In this connection, in each case several random numbers which are completely independent of each other can serve as code. However, in addition to one or more random numbers it is also possible to generate an algorithm which is also stored with the random number or numbers in the receiving device and the transmitting device. In this way, the number of codes which can be used until the next recoding is increased without too large a storage for the storing of a correspondingly large number of random numbers being required in the transmitting device.
The algorithm and the number of times it is used can be so selected that it is not possible to figure out the coding which will be used next from the previously recorded coded data recording before a new random number is used. In particular, even if several random numbers are stored, figuring out of the algorithm is made difficult by the fact that in the event of unauthorized recording of the coded data recording sent out by the transmitting device, it is not evident whether two successively recorded coded data are two data which are differently coded from each other due to the use once of the algorithm, whether two data which differ by repeated use of the algorithm are present (as would be the case if one or more coded data had not been recorded) or whether one of the coded data recorded represents a new random number.
The storing of a suitable number of random numbers and/or the deriving of further codes by means of an algorithm permits multiple effecting of the unlocking and locking without a new code having to be generated inbetween in the receiving device; in other words, the code used is changed from one unlocking or locking process to the next even if no recoding takes place. Thus it is possible to open and close a car several times with the use of a different code in each case without actuating the ignition switch in between. This is necessary, for instance, at camping sites where the vacationer only infrequently uses his car for driving but opens and closes the doors several times a day.
In one embodiment of the system, upon a recoding, ten random numbers are generated and the possibility is provided of varying each of the ten random numbers nine times by means of an algorithm. In this way, a hundred different codes can be used one after the other unless recoding is effected beforehand by actuation of the ignition switch.
In accordance with a further development of the invention, the algorithm can be made variable insofar as it is dependent on the random number which is applicable at the time. In this way it is possible, for instance, to use a first algorithm for the changing of the first random number stored after recoding and a second algorithm after the second random number, etc.
The transmission of the random number produced for the recoding and of the algorithm should be protected against unauthorized recording. In accordance with a further development of the invention, the transmission takes place when the ignition key, which is physically connected to the transmission device, is inserted into the ignition lock. The transmission can then take place over a very short path within the closed car so that unauthorized reception of the coded data recording from the outside becomes practically impossible.
In accordance with an improvement in this development, the transmitting of the random numbers and of the algorithm can take place at a time which is also determined on basis of random numbers and thus is not known to third parties. Due to the fact that after a recording a relatively large number of codes are stored, the system of the invention retains its reliable operation even if a recording which in itself is provided for and introduced does not in the final analysis take place, for instance because the driver of the vehicle again turns off the car before the above-mentioned time, determined on basis of random numbers, for the transmitting of the recoding has transpired.
In the system of the invention it need merely be seen to it that the same codes are present in both storages. For this purpose it is necessary to effect a transmission of the new code only when it has been established by suitable acknowledgement signals between the transmitting device and the receiving device that proper transmission is assured.
BRIEF DESCRIPTION OF THE DRAWINGS With the above and other objects and advantages in view, the present invention will become more clearly understood in connection with the detailed description of a preferred embodiment, when considered with the accompanying drawings, of which:
FIG. 1 is a simplified circuit diagram of a transmitting device;
FIG. 2 is a simplified circuit diagram of a receiver device;
FIG. 3 is a flowchart of programs for the microcomputers contained in the transmitting device and the receiver device;
FIG. 4 is a flowchart of a program for the further switching of the coding after an unlocking or locking process; and
FIG. 5 is a diagrammatic showing of the transmission path for the recoding.
In the figures the same parts bear the same reference numbers.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The transmission device 1 of FIG. 1 comprises a microcomputer 3 which is preferably developed as a single-chip computer and with which a piezoelectric crystal 4 is associated as clock. The current is supplied by a battery 7 which, in order to obtain smaller overall dimensions of the device of FIG. 1, is developed in the form of a button cell. A push-button switch 6 serves for turning on the transmitting device. One output 8 of the microcomputer 3 leads via an amplifier 9 to a light-emitting diode 10. A receiver 11 formed by a phototransistor is connected via another amplifier 12 to a coding input 13 of the microcomputer 3. The receiver 11 is furthermore connected to an activating input 14 of the microcomputer 3. This activating input 14 can furthermore be controlled via a diode 15 by the switch 6.
The operation of the transmitting device 1 as well as of the receiving device of FIG. 2 which is described in the following paragraph will be explained in further detail later on in connection with FIGS. 3 and 4.
The receiving device 2 also has a microcomputer 16 with a piezoelectric crystal 17. The microcomputer 16 is connected via the terminal 18 to the source of current of the vehicle (battery terminal 30). The terminal 19 is connected to the ignition switch (terminal 15) of the vehicle so that the microcomputer 16 is activated whenever the ignition is turned on.
Each of the inputs 20 of the microcomputer 16 is associated with a lock arranged in a door of the car and can, by mechanical actuation by means of a key, be used to activate the microcomputer 16 if the normal operation of the control device has been disturbed.
A generator 22 which produces random pulse trains is connected to another input 21 of the microcomputer 16. A transmitter 24 formed by a light-emitting diode is connected via an amplifier 23 to an output of the microcomputer 16. Furthermore, another transmitter 26 formed by another light-emitting diode is also connected via an amplifier 25 to an output of the microcomputer 16.
Receiving means 27 formed by a phototransistor are connected via an amplifier 28 to an input of the microcomputer 16. Each of the three inputs 29 of the microcomputer 16 leads to a locking device of the central locking system of the car and transmits the actuating signal given off by the microcomputer 16.
The program stored in the microcomputer 3 of the transmitting device is started up at 31 (FIG. 3) when the microcomputer 3 receives a corresponding command by the actuating of the push-button switch 6. Coded data recording is then sent out at 33 (with the aid of the light-emitting diode 10 in FIG. 1). After receipt of the coded data recording in the receiving device 2 by means of the phototransistor 27 and the amplifier 28 (FIG. 2), continuation of the program in the receiving device takes place at 34. As long as no data recording is received this program passes via the program part 36 into a wait loop.
At 35 it is determined from the coded data recording received what transmitting device (key) sent out the data recording. For this purpose, additional data recording is added to the coded data recording. For each of the keys to be used the same program run is provided, but with different variables. Otherwise, upon a switching from one code to the other or upon recording it would be necessary to recode all keys, which is impossible due to the different places where the keys are kept.
After it has been established, in the example shown in FIG. 3, that a main key (MK) is concerned, it is determined at 37 whether the coded data recording sent out represents a command which was coded with the code provided as next code for the actuating of the locking devices (existing code). If this is not the case it is then decided at 38 whether it is the code which was last used. If this is also not the case then the system of the invention assumes that an unauthorized code was used and passes via the program part 36, which is substantially delayed in order to make systematic trial and error difficult, again into readiness to receive.
However, if it is established at 38 that the last code used was sent out by the transmitter device, then an acknowledgement signal B is transmitted at 39 via the light-emitting diode 24 (FIG. 2) to the transmitting device, said signal being received by the phototransistor 11 (FIG. 1).
In the meantime the program of the transmitting device has passed from the sending of the coded data recording at 33, via a delay at 40 which determines the duration of the readiness to receive, to a branching 41 at which it is decided, as a function of the receipt of an acknowledgement signal, whether a repetition of the transmitted coded data recording is to take place at 42 or the code is to be changed at 43. If no acknowledgement is received by the transmitting device, then the code sent out is repeated four times, which is recorded in a branch 45. However, if an acknowledgement has been received then the code is changed at 43, as will be explained in further detail in connection with FIG. 4. At a further branching 44 the program is brought to the program part 42 if an acknowledgment signal B which indicated the reception of the previous code has been sent out by the receiving device. However, as will be described in more detail below, if the unlocking or locking of the doors is acknowledged by the receiving device by sending out an acknowledgement signal A, then the program is advanced from the branching 44 to the branching 46, this depending on whether the doors were locked or unlocked. At 47 and 48 a correspondingly different acoustic signal is given off in each case, whereupon the program is brought to its end 51 via the point 49 and via a program part 50 which disconnects the microcomputer 3.
If it has been determined at 37 that the existing code has been sent out it is tested at 52 whether the central lock is unlocked or locked. If the doors are locked (closed) then the program is continued at 54 with the sending out of an acknowledgement signal A to the transmitting device and an unlocking command is given at 56 to the central lock. If the doors, however, are unlocked upon the arrival of the coded data recording, then an acknowledgement signal A is sent out at 53 to the transmitting device and a locking command is given at 55. The code is then changed at 57, whereupon the program stays in the wait loop 34, 36 until the receipt of the next signal.
The flowchart of FIG. 4 is a more detailed description of the program parts 43 and 57 of the flowchart of FIG. 3. It is assumed that, upon a recording, N random numbers (Z1 to ZN) and an algorithm A are generated and stored in the transmitting device and the receiving device. Furthermore, the algorithm A is used in each case K times. The coding is then based on the following numbers Z1,k :
Z1,0, Z1,1, Z1,2 to Z1,K,
Z2,0, Z2,1, Z2,2 to Z2,K to
ZN,0, ZN,1, ZN,2 to ZN,K.
Upon reaching the program part 43 or 57 it is first of all determined whether the next code is to take place by the use of the algorithm A or by the reading of the next random number Zn from the storage. If k is smaller than K then the algorithm has still not been used as frequently as intended, so that the algorithm is used at 62 and thereupon the subscript k is increased by 1 at 63. However, if k is equal to K, then, by means of the program part 64, a new random number Zn,0 is read out of the storage, the subscript n is increased by 1 at 65 and the subscript k is set equal to 0 at 66. The program parts 67 to 71 are placed into action if a recording is effected by the transmitting device in which new random numbers Z1 to ZN and a new algorithm are determined and transmitted into the storages of the transmitting and receiving devices. At 68, the random numbers determined and the algorithm are stored. At 69 the random number (code) currently present as variable in the program is set equal to the first random number and at 70 and 71 the subscripts k and n are brought to their initial values.
As compared with the change of the random numbers by an algorithm which is constant up to the next recoding which has been described in connection with FIGS. 3 and 4, further security against unauthorized detection of the code can be obtained in the manner that the algorithm is variable. Thus, for instance, upon a recoding several algorithms can be removed from storage and used in a predetermined sequence. The use of the algorithms can, however, also be made dependent on the instantaneous random number. Thus, for instance, a first algorithm can be used when a given bit is the random number 0 and a second algorithm when this bit is 1.
FIG. 5 shows diagrammatically an embodiment of a transmitting device 1 which is arranged in the handle portion 80 of an ignition key 81. After the introduction of the key 81 into the ignition lock 82, the ignition can be turned on in known manner and the engine of the vehicle started. In this way random numbers and an algorithm are generated in the receiver device (FIG. 2), sent out via the light-emitting diode 26 and received by a phototransistor 11 in the transmitting device.
The transmission of the further coded data recording in accordance with the invention can be made "eavesdropper proof" in the manner that it is transmitted after a random period of time after the actuation of the ignition lock. The invention is also not limited to the transmission of the further coded data recording being brought about by the actuating of the ignition lock. Thus, for instance, the exceeding of a predetermined speed can bring about the transmission. Furthermore the system in accordance with the invention can be so developed that transmission can be brought about intentionally by the user, for instance by actuating a button on the key. In this embodiment the second transmitter of the receiving device can possibly be done away with and the first transmitter--arranged, for instance, on the vehicle itself--can effect the transmission. The user can then effect a new coding at a time that he feels is secure against an unauthorized recording.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS4048475 *Oct 26, 1976Sep 13, 1977Omron Tateisi Electronics CompanyApparatus for checking the user of a card in card-actuated machinesUS4352011 *Jan 23, 1980Sep 28, 1982Etablissement Public De Diffusion Dit "Telediffusion De France"Subscription card for a videotex receiverUS4471216 *Oct 27, 1980Sep 11, 1984Compagnie Internationale Pour L'informatique Cii-Honeywell Bull (Societe AnonymeSystem and process for identification of persons requesting access to particular facilitiesUS4509093 *Jul 11, 1983Apr 2, 1985Hulsbeck & Furst Gmbh & Co. KgElectronic locking device having key and lock parts interacting via electrical pulsesUS4535333 *Sep 23, 1982Aug 13, 1985Chamberlain Manufacturing CorporationTransmitter and receiver for controlling remote elementsUS4596985 *Nov 28, 1983Jun 24, 1986Kiekert Gmbh & Co. KommanditgesellschaftRadio-controlled lock method with automatic code change* Cited by examinerNon-Patent CitationsReference1 *EP 0140388, May 1985, Atalla.* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS4835407 *Oct 26, 1987May 30, 1989Nissan Motor Company, Ltd.Automotive antitheft key arrangementUS4849749 *Feb 25, 1987Jul 18, 1989Honda Lock Manufacturing Co., Ltd.Electronic lock and key switch having key identifying functionUS4988992 *Jul 27, 1989Jan 29, 1991The Chamberlain Group, Inc.Such as garage door, and a security deviceUS5055701 *Aug 15, 1989Oct 8, 1991Nissan Motor Company, LimitedOperator responsive keyless entry system with variable random codesUS5153581 *Jun 15, 1987Oct 6, 1992Bull, S.A.Method for authentication by an external medium of a portable object such as a memory card coupled to this mediumUS5229648 *Jan 4, 1991Jul 20, 1993Autosafe International, Inc.Multi element security systemUS5304812 *Nov 18, 1991Apr 19, 1994Sharp Kabushiki KaishaOptoelectronic device, information apparatus and data transmission system using optoelectronic device for simplifying wirings and reducing size, and method of controlling the optoelectronic deviceUS5365225 *Apr 6, 1990Nov 15, 1994Siemens AktiengesellschaftTransmitter-receiver system with (re-)initializationUS5377270 *Jun 30, 1993Dec 27, 1994United Technologies Automotive, Inc.Cryptographic authentication of transmitted messages using pseudorandom numbersUS5473200 *Oct 8, 1993Dec 5, 1995Depromax LimitedFrequency modulation digital code anti-theft systemUS5554977 *Apr 27, 1995Sep 10, 1996Ford Motor CompanyRemote controlled security systemUS5566212 *Apr 24, 1995Oct 15, 1996Delco Electronics CorporationPhase-locked loop circuit for Manchester-data decodingUS5598476 *Oct 26, 1995Jan 28, 1997United Technologies Automotive, Inc.Random clock composition-based cryptographic authentication process and locking systemUS5646456 *Dec 23, 1994Jul 8, 1997Nissan Motor Co., Ltd.Anti-theft car protection systemUS5646996 *Sep 5, 1995Jul 8, 1997United Technologies Automotive, Inc.Automatic resynchronization of transmitter in the event of corrupted memoryUS5670933 *Jun 21, 1995Sep 23, 1997Toyota Jidosha Kabushiki KaishaAntitheft apparatus and method for an automobileUS5679984 *Feb 16, 1995Oct 21, 1997Rover Group LimitedVehicle security systemUS5724028 *Jun 3, 1997Mar 3, 1998United Technologies Automotive, Inc.RF remote system with drive-away preventionUS5774065 *Aug 2, 1995Jun 30, 1998Nippondenso Co., Ltd.Remote control system and method using variable ID codeUS5916290 *Oct 15, 1997Jun 29, 1999Nippondenso Co., Ltd.Airbag device having combined fault diagnosis and type signaling indicatorUS5978483 *Jun 18, 1997Nov 2, 1999Inkel CorporationSecurely encrypted remote keyless entry systemUS6097307 *Aug 15, 1997Aug 1, 2000National Semiconductor CorporationSecurity system with randomized synchronization codeUS6154544 *Jun 11, 1997Nov 28, 2000The Chamberlain Group, Inc.Rolling code security systemUS6175312Dec 4, 1992Jan 16, 2001Microchip Technology IncorporatedEncoder and decoder microchips and remote control devices for secure unidirectional communicationUS6690796Jan 21, 2000Feb 10, 2004The Chamberlain Group, Inc.Rolling code security systemUS6980655Oct 17, 2001Dec 27, 2005The Chamberlain Group, Inc.Rolling code security systemUS7412056Sep 29, 2003Aug 12, 2008The Chamberlain Group, Inc.Rolling code security systemUS7492898Jul 2, 2004Feb 17, 2009The Chamberlain Group, Inc.Rolling code security systemUS7492905Aug 14, 2002Feb 17, 2009The Chamberlain Group, Inc.Rolling code security systemUS7623663Dec 21, 2005Nov 24, 2009The Chamberlain Group, Inc.Rolling code security systemUS8056538 *Dec 2, 2008Nov 15, 2011GM Global Technology Operations LLCMethod and system to prevent unauthorized uses of engine controllersUS8194856Jul 22, 2008Jun 5, 2012The Chamberlain Group, Inc.Rolling code security systemUS8233625Jul 22, 2008Jul 31, 2012The Chamberlain Group, Inc.Rolling code security systemUS8284021Jul 22, 2008Oct 9, 2012The Chamberlain Group, Inc.Rolling code security systemUS8633797Sep 26, 2012Jan 21, 2014The Chamberlain Group, Inc.Rolling code security systemUSRE35364 *Apr 20, 1995Oct 29, 1996The Chamberlain Group, Inc.Coding system for multiple transmitters and a single receiver for a garage door openerUSRE36181 *Nov 8, 1996Apr 6, 1999United Technologies Automotive, Inc.Pseudorandom number generation and crytographic authenticationUSRE36703 *Aug 12, 1996May 16, 2000The Chamberlain Group, Inc.Coding system for multiple transmitters and a single receiver for a garage door openerUSRE36752 *Dec 23, 1996Jun 27, 2000United Technologies Automotive, Inc.Cryptographic authentication of transmitted messages using pseudorandom numbersUSRE37986Feb 15, 2000Feb 11, 2003The Chamberlain Group, Inc.Coding system for multiple transmitters and a single receiverEP0957220A1 *Jul 10, 1996Nov 17, 1999Yi ShiAutonomous random dynamic cryptogram lock systemWO2005083210A1 *Feb 28, 2005Sep 9, 2005Blake Christopher IanAn access control system* Cited by examinerClassifications U.S. Classification340/5.26, 361/172, 340/5.72International ClassificationE05B49/00, G07C9/00Cooperative ClassificationG07C2009/0042, G07C2009/00785, G07C9/00309European ClassificationG07C9/00E4Legal EventsDateCodeEventDescriptionSep 22, 1992FPExpired due to failure to pay maintenance feeEffective date: 19920719Jul 19, 1992LAPSLapse for failure to pay maintenance feesFeb 19, 1992REMIMaintenance fee reminder mailedAug 18, 1986ASAssignmentOwner name: VDO ADOLF SCHINDLING AG,GRAFSTRASSE 103, 6000 FRANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:RATHMANN, KLAUS;JANOFSKE, RUPERT;SCHRODER, HANS-JOACHIM;AND OTHERS;REEL/FRAME:004593/0245Effective date: 19860717Owner name: VDO ADOLF SCHINDLING AG, A CORP. OF GERMANY,GERMANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:RATHMANN, KLAUS;JANOFSKE, RUPERT;SCHRODER, HANS-JOACHIM;AND OTHERS;REEL/FRAME:004593/0245Owner name: VDO ADOLF SCHINDLING AG, GERMANYRotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google