Patent GB-1466029-A (GB)
Title: Linkage for the operation of a remote element-
IPC: F02D11/02
Filed: 1975-05-23
Abstract: 1466029 Linkwork FORD MOTOR CO Ltd 23 May 1975 [10 June 1974] 22612/75 Heading F2K [Also in Division F1] A motor-vehicle throttle pedal lever 16 is connected to an engine throttle lever 38 by a cable 22 which passes over the periphery of and is anchored to an irregularly shaped pulley 18 which is locked in a set position on the pedal lever 16 for normal operation of the engine, the pulley 18 being unlockable from the pedal lever 16 to allow relative turning movement thereto which prevents or restricts operation of the throttle lever 38, on inadvertent manual operation of the pedal 16, to prevent possible engine damage when the vehicle's automatic transmission (not shown) is in "PARK" or "NEUTRAL" &c. or when the automatic transmission is placed from neutral into a forward or reverse gear, such overspeed protection being desirable in vehicles having high revving rotary or turbine engines. Additionally, the throttle linkage arrangement could form part of a vehicle's anti-theft system in which significant vehicle speeds could not be obtained until the speed control linkage was re-established. As shown, the pedal lever 16 is fulcrumed at 14 and the pulley 18 is fulcrumed at 19 on the upper end of the lever 16. The pulley 18 has a shaped cutaway with end faces 24, 26 which respectively engage a pin 27 fast on the lever 16 and a spring extended plunger 28 of a solenoid 29 also secured to the lever 16, the pin 27 and plunger 28 serving to lock the pulley 18 in the set position (i.e. when the solenoid 29 is not energized) for normal engine operation via the cable 22. A spring 33 is anchored between points 34 and 35 on the pulley 18 and pedal lever 16 and serves to bias the pulley 18 to its normal set position against pin 27. The solenoid 29 is arranged in a circuit 47 with a battery 46, ignition switch 42 and a pair of normally open switches 43, 44 positioned in parallel, the switch 43 being closed when the transmission selector lever (not shown) is placed in "PARK" and the switch 44 is closed in "NEUTRAL". Thus when the ignition switch 42 and one of the transmission selector switches 43, 44 are closed the solenoid is energized and the pulley 8 unlocked such that if the pedal lever 16 is operated the tensile loading in the cable 22 overcomes the spring 33 to turn the pulley 18 relative the lever 16 whereby the throttle opening is prevented or limited to a predetermined magnitude such that possible damage from over revving of the engine is prevented. The arrangement is such that the cable 22 is connected to the engine throttle lever 38 which is biased towards a closed position by a tension spring 39 which increases in resistance on operation of the pedal lever 16, such resistance acting via the cable on the pulley 18 to oppose the loading of the spring 33 on the pulley 18, the latter spring 33 being connected such that the distance of its line of action reduces as its spring load increases as it is extended during operation of the pedal 16 whereby when the effective moment of spring 39 acting via cable 22 on pulley 18 equals or exceeds that of spring 33 the pulley 18 turns relative the lever 16 and no further opening of the engine throttle lever 38 can be effected by the movable pedal lever 16.