Patent GB-421894-A (GB)
Title: Improvements in and relating to clutch-operating devices for power transmission systems
Filed: 1933-07-06
Abstract: 421,894. Operating clutches; variable-speed gearing. GILLETT, E. H. J. C., 32, Marlborough Mansions, Cannon Hill, West End Lane, London. July 6, 1933, Nos. 19170 and 30373. Divided out of 416,663. [Class 80 (ii)] The spring-engaged clutch of a motor-vehicle is disengaged by a servomotor 58, Fig. 3, which is constantly open, through a port 64, to oil supplied to an annular recess 62 through a pipe 50 by a gear pump 46, 47, the servomotor being controlled by a valve sleeve 72 which is operated by an engine - driven governor and which controls relief ports 71, leading from the groove 62, in a sleeve 70 which is connected to the servomotor piston 59 by a lever 65<a> so as to followup the sleeve 72, whereby for any given speed within the operative range of the centrifugal control there is a definite position of the piston 59. A piston valve 92, connected to the accelerator pedal 14, Fig. 1, by a rod 21, closes additional relief ports 91 at small throttle openings, but above a predetermined throttle opening the valve 92 opens these ports to cause complete clutch engagement at all speeds. The pump is driven by a shaft 45 driven from the engine, this shaft being formed with a drum 51 carrying the pivoted governor weights 52 which act on the sleeve 72, through a sleeve 56, a thrust ball 75, and a spindle 73 against a collar 85 on which the sleeve 72 is held by a spring 74, against the action of a pair of independently-adjustable springs 77, 78. The spring 77 acts directly on the end of the spindle 73, while the spring 78 acts on the collar 85 through a ring 84 which coacts with an adjustable stop 79<a> in such a way that the spring 78 only comes into action at an adjustable point in the clutch engaging stroke, so as to cushion the final part of the stroke. The clutch can be disengaged at all speeds by moving inwards a rod 32 which is adapted to move the sleeve 72 against the action of the spring 74 by engagement with a pin 88 fixed in the sleeve, and passing through slots 89 in the spindle 73. The servomotor, pump, and control mechanism are housed within a casing 22 adapted to be mounted on the engine 10 ; a chamber 22<a> within the casing constitutes the pump reservoir, the oil in which serves to lubricate the parts. The lever 65<a> is fixed to a shaft 66 which carries an arm 26, Fig. 1, connected by a slotted link 27 to the clutch pedal 13. The rod 32 is connected by a link 34 and lever 36 to a shaft 104 in the gear-box 12, and, by mechanism identical with that shown in Figs. 4 and 5 of Specification 395,692, the clutch is caused to disengage whenever the gear lever 15 is moved to effect a gear change and can only be reengaged on completion of the gear shift. The Specification states that, instead of operating the clutch, the servomotor may operate the friction brake means controlling the gear trains of an epicyclic change-speed gear. Specification 416,663 also is referred to. According to the first Provisional Specification, the governor, the servomotor piston, and a single valve member may be interconnected by a rigid linkage, and the servomotor, which may be pneumatic, may act to engage the clutch, while according to the second Provisional Specification the single valve may have an over-riding connection with the throttle.