Device and process for limiting access to authorized users

• US 6,073,064 A
• Filed: 06/04/1997
• Issued: 06/06/2000
• Est. Priority Date: 06/06/1996
• Status: Expired due to Fees

• Current Assignee: Delphi Automotive Systems LLC (BorgWarner Incorporated)
• Original Assignee: Delphi Automotive Systems LLC (BorgWarner Incorporated)
• Inventors: Weiss, Bernd, Konrad, Reimund, Petsching, Wilfried
• Primary Examiner(s): Zanelli, Michael J.
• Application Number:
  US08/869,060
• Time in Patent Office: 1,098 Days
• Field of Search: 701/1, 701/36, 340/426, 340/825.31, 307/10.2, 307/10.3, 307/10.4, 307/10.5
• US Class Current: 701/36
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: G07C 2009/00769 with data transmission performed by wireless means
• CPC Class Codes: G07C 2009/00873 by code input from the lock
• CPC Class Codes: G07C 9/00857 where the code of the data carrier can be programmed

Abstract

A device for limiting access to authorized users, for example, a vehicle access limiting device, includes a control device and a key device. The control device has memory wherein a preset user code and a preset secret code are stored. The key device has a transponder which includes a memory for storing the user code and the secret code transferred from the control device. The transponder emits the user code which has been encoded with the transferred secret code. The control device includes a comparison device which allows access only when the encoded user code emitted by the transponder agrees with preset information stored in the control device. The key device also includes a comparison device which prevents overwriting of the taught secret code unless it also receives the taught user code. In the event of failure of the control device, a second control device with a new user code and a new secret code can be used with the key device, after which the second control device teaches the key device the new user code and the new secret code.

Claims

1. A device for limiting access to authorized users, comprising:

(a) a control device, comprising a memory for storing a preset secret code and a preset user code; and

(b) a key device, comprising a transponder having a memory for storing the secret code and the user code which is transferred by said control device in a secret code area, wherein the transponder emits as information the user code which has been encoded according to the secret code;

(c) a first comparison device in said control device which permits access only when it detects agreement between the information received from said transponder comprising said user code encoded according to said secret code and with said user code stored in said control device; and

(d) a second comparison device coupled with a locking device in said key device which permit overwriting of said secret code stored in said memory of said key device only if said comparison device first detects agreement between the user code already stored in said key device and the user code transferred from said control device.

2. The access limiting device according to claim 1 installed in a vehicle and limiting access to said vehicle to authorized users.

3. The access limiting device according to claim 1 wherein the locking device comprises lock bits.

4. The access limiting device according to claim 1 wherein said key device further comprises a counter for counting the number of times the user code is transferred from said control device to said key device.

5. The access limiting device according to claim 4 wherein the counter has a limit value for the number of transfers that may occur which, when reached, blocks further overwriting of the secret code in said key device.

6. The access limiting device according to claim 1 wherein the secret code area comprises several sections.

7. The access limiting device according to claim 6 wherein one of the sections is presettable in a key-device-specific way and another section is presettable in a control-device-specific way.

8. The access limiting device according to claim 7 wherein the section presettable in a control-device-specific way comprises the user code.

9. The access limiting device according to claim 1 wherein said control device and said key device are electrically connected to each other by a chip card.

10. The access limiting device according to claim 1 wherein said control device and said key device are electrically connected to each other capacitively or inductively.

11. A process for limiting access to authorized users in an access limiting device, comprising a control device wherein a preset secret code and a preset user code are stored, and a key device having a transponder which exchanges data bidirectionally with said control device, said process comprising the steps of:

(a) transferring the secret code and user code from the control device to the key device wherein they are stored;

(b) encoding the transferred user code in the key device according to the secret code;

(c) emitting the encoded user code from the transponder to the control device;

(d) comparing the encoded user code received from the transponder in the control device with preset information fixed in the control device, and, if it agrees, allowing access to the access limiting device; and

(e) if the control device is replaced with a second control device having a second secret code, comparing the user code transferred by said second control device with the user code already stored in said key device and, if they agree, permitting the secret code already stored in said key device to be overwritten with said second secret code of said second control device.

12. The process according to claim 11 wherein the access limiting device is a locking device for vehicles.

13. The process according to claim 11 wherein the secret code already stored in the key device can be overwritten only if a preset number of transfers of the user code has not been exceeded.