812,350. Change-speed and clutch control. HUMBER Ltd., and BROWN, R. H. July 28, 1955 [July 30, 1954], No. 22364/54. Class 80(2). A combined clutch and throttle control, for use e.g. in gear shifting on a vehicle, comprises a motor 20 for automatically closing the engine throttle simulteneously with energizing a clutch disengaging motor, not shown, and a further motor 21 under control of a switch 70 differentially driven from the input and output shafts 73, 72 of the clutch, for re-opening the throttle to synchronize the clutch and delay its re-engagement if its output speed exceeds that of its input whilst disengaged. As shown enginemanifold depression energizes the clutch release and throttle motors, but the clutch motor may be suction-tripped hydraulic; or hydraulic, compressed air or electric motors may be used for both clutch and throttle, and the clutch may be centrifugal. In Figs. 1 and 4, energization of a solenoid valve 50 through a switch closed by a gear-shift lever during shift (as in Specification 619,223) directs engine suction in a passage 58, connected to the engine manifold at 60 and to a reservoir at 59, simultaneously to clutch-release and throttle-close passages 62, 64. If, during clutch-release output 72 overruns input 73, the switch 70 closes to energize a solenoid valve 51 directing suction 58 to a throttle-open passage 66 which cuts off an atmospheric release passage 56 not only from its own passage 66, but also from those 62, 64 of the clutch-release and throttle-close motors, so that even if the solenoid valve 50 is de-energized by release of the gear-shift lever, the clutch will be maintained released until slight overspeed of the input 73 re-opens the switch 70, to de-energize the throttle-open solenoid valve 51 thereby cutting off the suction passage 58 and connecting the clutch-release and throttle-close and open passages 62, 64, 66 to atmosphere at 56, as shown (if the shift lever has been released), permitting the clutch to re-engage and restoring throttle control to the driver. Two methods of throttle operation are described. In the first, Fig. 1, the accelerator pedal 22 is connected to the engine throttle 25 through a link 29, lostmotion connection 30, closed by a spring 31, bellcrank 28, link 33, lost-motion connection 36, bellcrank 38, link 39 and arm 24, loaded by a closure spring 26. Also operating on the bellcranks through lost-motion connections are the throttle closing and opening diaphragm motors 20, 21 fed by the respective solenoid valves 50, 51. With both diaphragms 20, 21 de-energized, as shown, the accelerator pedal 22 operates the throttle 25 directly, whilst energizing of either diaphragm 20, 21 respectively closes or opens the throttle independently of pedal position. In the second form, Figs. 8 and 9, accelerator- and throttle-linked spindles 100, 102 are normally invariably connected by a combined bellows and cylinder assembly 113 which, during throttle operation, slides on a fixed centre post 112. Suction applied to the clutchconnected passage 64 (see also Fig. 4) by the throttle-close solenoid valve 50, contracts the bellows 110, shortening the assembly 113, thus closing the throttle. Suction applied to the passage 66 by the throttle-open solenoid valve 51, acts on the left of a piston 128 in the cylinder section of the assembly, which piston slides relatively to the right, taking with it a collar which turns an arm 118 on the throttle-spindle 102, thereby opening the throttle, all independently of the setting of the accelerator spindle 100. For re-opening the throttle after closure by suction collapse of the bellows 110, air, returned to the clutch passage 64 by the solenoid valve 50, reaches the bellows chamber first by expanding a resilient band 143 closing a port communicating with the interior of the post 112, air later entering at a port 122 initially covered by the end cap of the bellows. Air may bleed in at a rate controlled by a needle restrictor (not shown), by-passed during energizing by a non-return valve. Specification 761,240 also is referred to.