GB437132A - Improvements relating to the control of motor vehicles - Google Patents

Abstract

437,132. Preventing reverse movement of motor vehicles. STANCLIFFE, C. W., Warrani, Harlequin Lane, Crowborough, Sussex. May 25, 1934, No. 15692. [Class 103 (i)] A sprag, including a coil spring clutch for preventing reverse movement of a vehicle, when rendered inoperable remains so after subsequent reverse movement of the vehicle until a forward gear is engaged and the vehicle moves forward. The pawl 6 of the sprag prevents movement of the vehicle transmission shaft 4 in the reverse direction shown by the arrow 14 unless a stop 15 is raised and allows the pawl 6 to be swung clear of the ratchet wheel and against a stop 13 by a spring clip frictionally gripping a disc 11 on the transmission shaft 4, on reverse movement of the vehicle. The pawl 6 is not swung back to operative position again until the vehicle moves forward and the disc 11 is turned. The stop 15 is raised by a cam on the reverse gear shift rod 17 when reverse gear is engaged and is held in this position by a catch 39 on a rod 27 connected to the stop 15, the catch 39 engaging the edge of a slot 30 in a sliding member 31, when this is at the right hand limit of movement. The sprag is thus held inoperative when the gear lever is moved back to neutral and until the gear lever is moved to a forward gear when cams on the gear shift rods 17, 37 engage members 35, 36 on the member 31 which is moved to the left to release the stop 15 into operative position. The sprag may be rendered inoperative manually by a rod 21 and an inclined member 24. The knob 22 may be outside the body of the vehicle. The ratchet wheel 5 is freely mounted on the shaft 4 and is connected to one end of a coil spring clutch, which is enclosed in a cylindrical bore and fixed at the other end to the shaft 4. When the wheel 5 is locked by the pawl 6, reverse movement expands the coil spring against the bore and locks the shaft 4. A spring plunger may be used to assist the return of the pawl 6 to operative position. The coil spring clutch may be connected to the ratchet wheel 5 by a clutch which is released by a pedal to render the device inoperative without altering the positions of the normal controls. The upper surface of the shift rod 17 may be so formed that the sprag is rendered inoperative by only partial movement of the gear lever towards the reverse gear position.