TRANSMISSION CONTROL LOCKING DEVICE

Abstract: This invention relates to a motor vehicle immobilising device which is adapted to disable the drive train of the motor vehicle under the control of known remotely controllable locking means adapted releasably to lock an actuator member constituted by a transmission gear selector lever (74) in a predetermined position when the lever is moved to that position. The predetermined position of the lever (74) coincides with the position of a gear selection which disables the vehicle drive train. This could be achieved by disengaging the gear box, that is by selecting the "neutral" position of the transmission or, in automatic gear boxes, by selecting the "park" position of the transmission, or in all types of gearboxes, by selecting the "reverse" position of the transmission. The object in each case is essentially to make is difficult, if not impossible, to drive the vehicle away in any normal manner. The immobilising device may be adapted releasably to lock the clutch actuation lever (10) the locking means being adapted to lock the lever (10) in a disengaged position of the clutch by means of a spring-loaded solenoid catch adapted to engage the lever when the lever is operated while the solenoid is de-energised. Energisation of the solenoid allows disengagement of the clutch and permits normal operation thereof.

Description: This invention relates to a motor vehicle immobilising device. Simple locking devices for vehicle transmissions have been proposed. One such device comprises a plate which fits over the gear lever of a motor vehicle and which is locked in position, thereby preventing operation of the gear lever. In addition pedal locks have been proposed by means of which, for instance, the clutch pedal of the motor vehicle could be locked relatively to the vehicle body, thereby preventing depression of the clutch pedal. A more sophisticated clutch lock is described in French patent no. 2,572,037 - BARBAROT. This patent describes an anti-theft device which incorporates an encoder arrangement linked to an electromagnetically operable catch which, in turn, engages a multiple rocker arm capable of locking the clutch lever against movement indirectly by engagement of the clutch cable. French Patent No. 996,062 - GUILLOU ET AL, US patent no. 2,992,693 - PEYTON and US patent no. 3,610,004 - GENERAL MOTORS CORPORATION, all describe drive shaft locking means. US patent no. 3,718,202 - TEXAS INSTRUMENTS INC. describes a transmission locking system in which an encoding and decoding device is used to energise or de-energise a drive train locking mechanism. The locking mechanism of this patent is constituted by a gear dog which may be interposed between the gears in the transmission locking system of the motor vehicle, to lock the gears to one another when the vehicle transmission is in the "park" position. US-A-1 972 300, on which the preamble to claim 1 is based, discloses a device with a solenoid-controlled pawl that engages in one of a row of notches in a slide bar that forms part of the linkage from a gear-shift lever. The invention provides a motor vehicle immobilising device comprising remotely controllable locking means adapted releasably to lock a link forming part of the vehicle transmission gear selector linkage in a predetermined position coinciding with a "reverse", "neutral" or "park" position of the transmission, when the link is moved to that position, characterised in that the link is an initial link, which emerges from the transmission housing, in the linkage and that the link includes an enlarged heel in which an aperture, adapted to receive a locking bolt forming part of the locking means, is formed. The vehicle drive train may be disabled either by disengaging the gear box, that is by selecting the "neutral" position of the transmission or, in automatic gear boxes, by selecting the "park" position of the transmission, or in all types of gearboxes, by selecting the "reverse" position of the transmission. The object in each case is essentially to make it difficult, if not impossible, to drive the vehicle away in any normal manner. In the drawings: Figure 1 is a part-sectional view of an automatic transmission locking device according to the invention; and Figure 2 is a side view of the locking mechanism of the transmission locking device of Figure 1. The immobilising device of the invention finds particular application as an anti-theft device and, to this end, can be provided with any one of a number of known encoding and decoding devices by means of which the locking means may be activated and deactivated. The locking means serves, essentially, to disable the drive train of the vehicle by locking a transmission actuator in a position such that the drive train is disabled. This may be done by locking the gear selector lever of the vehicle in "neutral", in "park" or in "reverse". This arrangement differs from the arrangements discussed above with reference to the prior art in that the clutch locking mechanism of French patent no. 2,572,037 - BARBAROT engages a push rod or clutch cable extending between the clutch pedal and the clutch actuation lever. Of course, in an anti-theft device, this leaves open the possibility of the disconnection of the clutch actuating lever from the locked cable or push rod and the operation of the vehicle without the use of the clutch. This would, of course, allow the anti-theft device to be defeated. The drive shaft locking mechanisms described in US patents nos. 3,610,004 - GENERAL MOTORS CORP. and 2,992,632 - PEYTON and in French patent no. 996, 062 GUILLOU ET AL are, in effect, park mechanisms which, in view of the leverages involved, could be easily destroyed by a person wishing to defeat the drive shaft lock. The locking mechanism descried in US patent no. 3,718,202 - TEXAS INSTRUMENTS INC., locks the gears of the vehicle transmission to one another rather than locking the gear selector mechanism. The result is a relatively expensive and intrusive device which would have to be built into the gear box as opposed to the device of the invention which can be attached to the side of the gear box, if desired. Figures 1 and 2 illustrate a locking device for an automatic transmission. The locking device is encased in a sturdy housing 70 which is bolted onto the transmission casing 72. The transmission is operated by a gear selector lever 74 which is fixed to a shaft 76 and which is operated by a selector rod 78. The selector lever 74 has an enlarged heel 80 in which is formed an aperture 82. A bracket 84 inside the housing 70 carries a solenoid 86 with a spring loaded plunger 88 which fits into the aperture 82. The solenoid 86 is operated by a remotely controlled electronic circuit 90. When the solenoid 86 is energised, the plunger 88 is retracted against the urging of a spring 92 and the selector lever 74 is free to operate normally. When the solenoid is de-energised, the plunger 88 bears against the enlarged heel 80 of the operating lever 74 under the force of the spring 92 and as foon as the lever 74 is moved to the "park" position, the plunger 88 enters the aperture 82, preventing further movement of the lever 74. The aperture 82 can be positioned to lock the selector lever 74 in some other position, such as the "neutral" position, for instance, or the "reverse" position, the intention in each case being to lock the transmission in a position in which the vehicle is either actually immobilised or difficult to drive in any normall manner. The solenoid 88 has an extension 94 which protrudes beyond the end of the solenoid remote from the bracket 84 when the solenoid is energised. A lockable access plate 96 is fitted to the housing 70 and is locked in position by means of a key operated mechanism having two fingers 98. A spring loaded pawl 100 locks one of the fingers 98 in position when the solenoid is de-energised. When the solenoid is energised, the extension 94 presses against the pawl 100, allowing the fingers 98 to be moved if desired. This mechanism prevents removal of the access cover 96 by unauthorised persons, even if they have a key, while the solenoid 86 is de-energised. The transmission locking device of the invention can be built into the vehicle gearbox or automatic transmission at the factory, reducing the cost of the device and making it more difficult to detect.

Claims: A motor vehicle immobilising device comprising remotely controllable locking means adapted releasably to lock a link forming part of the vehicle transmission gear selector linkage in a predetermined position coinciding with a "reverse", "neutral" or "park" position of the transmission, when the link is moved to that position, characterised in that the link is an initial link (74), which emerges from the transmission housing (70), in the linkage and that the link includes an enlarged heel (80) in which an aperture (82), adapted to receive a locking bolt (88) forming part of the locking means, is formed. A motor vehicle immobilising device according to claim 1, characterised in that the locking means includes a bolt constituted by a spring loaded plunger (88) which fits into the aperture (82) in the enlarged heel (80) of the link (74), a solenoid (32) being energisable by a remotely controlled electronic circuit which is adapted to retract the plunger (88) against the urging of the spring (92) to free the link (74) for normal operation within the linkage and the plunger (88), with the solenoid de-energised, being adapted to bear against the enlarged heel (80) of the link under the force of the spring (92) and to enter the aperture (82) in the heel (80) in the predetermined position of the link, thereby to prevent further movement of the link. A motor vehicle immobilising device according to claim 2, characterised in that the device is housed within a housing (70) adapted for securement to the vehicle gear box housing (72), the solenoid (86) having an extension (94) which protrudes beyond the end of the solenoid (86) remote from the plunger (88) when the solenoid (86) is energised, the device housing (70) including a lockable access plate (96) which is lockable in position by means of a key-operated mechanism having a plurality of retractable fingers (98), a spring loaded pawl (100) being provided to lock at least one of the fingers (98) in a locking position when the solenoid (86) is de-energised and the extension (94) on the solenoid (86) being adapted, upon energisation of the solenoid (86) being adapted, upon energisation of the solenoid (86), to engage and move the pawl (100) to release the locked finger (98) to allow the fingers (98) to be retracted. A motor vehicle fitted with an immobilising device as claimed in any one of claims 1 to 3.

Inventors: DURIGON, DUILIO
Applicants: DURIGON, DUILIO
Application year: 1987
Main classification: B60R25
IPC codes: B60R25