Patent GB-282121-A (GB)
Title: Improvements in or relating to clutches
IPC: F16D23/12
Filed: 1926-06-18
Abstract: 282,121. Carling, W. T. June 18, 1926. Clutches, claw; variable-speed gearing.-Claw clutches for use in motor car speed-gearing &c. are provided with means for effecting engagement only when the clutch parts are moving substantially at identical speeds and with auxiliary means for effecting engagement when the car &c. is stationary. The driving (or driven) part 2 carries clutch jaws 2a engaging between jaws 4a on the slidable driven (or driving) part 4. A ring 3 capable of limited free rotation relatively to the part 2 and also loose on the driven shaft 5 rigidly carries jaws 3<a> capable of forming with the jaws 2<a>, as shown in Fig. 2, complete jaws for engagement by the jaws 4a. A slot 4d in the member 4 is adapted to engage with sufficient friction upon a sleeve extension 3<b> of the ring 3, when the member 4 is advanced, to cause the parts 3 and 4 to move together in so far as is permitted by the limited freedom of the ring 3 on the part 2. Spring-pressed levers 2b pivoted in the part 2 normally engage with a groove 3i in the ring 3. The part 4, however, in moving forward for clutch engagement bears also upon axially slidable pins 2f which, through springs 2<g> and pins 2<h>, oppose the springs 2e so that at the moment that the relative movement between the parts 2, 4 changes its direction and the parts 3, 2 are rotated relatively, the lever ends enter notches 3<k> in the ring 3, which is locked with its jaws 3a in position to permit clutch engagement. In the form shown in Figs. 4 and 6, complete clutch teeth 2a, 4a are provided, and the ring 3, which carries fingers 3<c> engaging slots in the part 4, is provided also with spring fingers 3d or spring-pressed fingers arranged on either side of the fingers 3<c> and serving to connect the parts 3, 4 frictionally during the first part of the clutching-movement so as to prevent undue rotation between them, the fingers ultimately entering the slots in the part 4. Additional friction between the parts 2, 3 during the axial movement of the clutch member 4 is obtained by providing coned surfaces 2<a>, 3f on the said parts. The ring 3 may prevent clutch engagement at one end of its rotary travel and permit it at the other, for example in the highest and lowest gear clutches. When it is desired to change the gear, the clutch already in action is disengaged and the engine accelerated for changing down, or for changing up is slowed before the previous gear is disengaged by automatic adjustment of the throttle during movement of the change-gear lever, as described in Specification 234,238. Movement of the changegear lever may, if desired, stress a spring tending to engage the clutch, or the lever may be manually operated at the moment the relative speeds of the clutch parts 2, 4 reverse in direction. To provide for clutch engagement when the car is stationary, the means shown in Figs. 9 and 10 may be employed to rotate the ring 3 to its central position. Ratchet teeth 3<k> on the ring are engaged by a spring-held pawl 8 pivoted on a rod 8<a> connected by springs 9b, 9<c> to a sleeve 9 actuated by a lever 11<b> linked to a pedal 11, which is interlocked with the main car clutch pedal 10<a> so that the pedal 11 can only be moved when the clutch is disengaged and the clutch can only be re-engaged when the pedal 11 is released. The gear-changing lever 21 is provided with a catch to prevent the depression of the pedal 11 while the reverse gear is being engaged. Fig. 11 shows an alternative device for starting from rest, in which a plate 16 slidable relatively to the clutch part 4 carries wedges 16<a> which engage the ends of the fingers 3<c> so as to move them to their central position. Specification 2385/12 also is referred to.