Optical theft deterrent system

• US 5,043,593 A
• Filed: 07/10/1989
• Issued: 08/27/1991
• Est. Priority Date: 07/11/1988
• Status: Expired due to Fees

• Current Assignee: Kokusan Kinzoku Kogyo Kabushiki Kaisha
• Original Assignee: Kokusan Kinzoku Kogyo Kabushiki Kaisha
• Inventors: Ozawa, Takurou, Tsutsumi, Shunsaku
• Primary Examiner(s): Pellinen, A. D.
• Assistant Examiner(s): Elms, Richard T.
• Application Number:
  US07/377,904
• Time in Patent Office: 778 Days
• Field of Search: 361/171, 361/172, 361/160, 361/139, 307/10.2, 307/10.5, 307/311, 307/9.1, 307/10.1, 307/10.3, 70/278, 70/D 51, 250/229, 250/215, 250/227, 340/531, 340/539, 340/425.5, 340/426, 340/825.31, 340/825.34, 340/825.69, 340/825.32, 180/287
• US Class Current: 307/10.2
• CPC Class Codes: B60R 25/021 restraining movement of the steering column or steering wheel hub, e.g. restraining means controlled by ignition switch
• CPC Class Codes: B60R 25/04 operating on the propulsion system, e.g. engine or drive motor
• CPC Class Codes: B60R 25/2063 Ignition switch geometry
• CPC Class Codes: B60R 25/24 using electronic identifiers containing a code not memorised by the user
• CPC Class Codes: E05B 49/006 actuating opto-electronic devices
• CPC Class Codes: G07C 2009/00785 by light
• CPC Class Codes: G07C 9/00944 Details of construction or manufacture
• CPC Class Codes: Y10T 70/7079 Key rotated [e.g., Eurocylinder]

Abstract

A new optical theft deterrent device wherein a ray from a light source is divided by a beam splitter mounted on a key into a plurality of light beams which are detected by photosensors to determine authorized use of the key only when predetermined one or ones of the photosensors produce electrical outputs. The beam splitter serves to uniformly divide the ray from the light source into the light beams and also to accurately guide these beams toward the photosensors. The key may be utilized to mechanically and electrically unlock a locking device. The new system may preferably be applied to a steering column shaft locking device to prevent theft of an automotive vehicle on which the system is equipped.

Claims

1. An optical theft deterrent system comprising key means and lock means;

said key means including a key blade and a key head, said key blade being provided with notches for mechanical key code, said key head including a beam splitter which comprises an input end for receiving a ray;

a transmitting portion having a plurality of optical paths divided from said input end for optical key code;

an emitting end formed at each end of said optical paths;

said lock means comprising electric lock means and mechanical lock means operable by said key blade of the key means;

said electric lock means including a light source for producing the ray;

switching means provided in said lock means and being turned on to radiate the ray from the light source toward the input end of the beam splitter when said mechanical lock means is unlocked by the key means;

a plurality of photosensors for selectively receiving rays forwarded from said emitting ends of the beam splitter;

a comparator for producing a drive signal only when a predetermined combination of said photosensors generates an output; and

a driven device operated by the drive signal from said comparator.

2. An optical theft deterrent system as defined in claim 1 wherein said light source includes two infra-red emitting diodes positioned angularly apart from said photosensors.

3. An optical theft deterrent system as defined in claim 1 wherein said beam splitter is T-shaped.

4. An optical theft deterrent system as defined in claim 1 wherein at least one of the output ends of the beam splitter is cut off or interrupted to prevent emission of the light beam on corresponding one of said photosensors.