Patent GB-577339-A (GB)
Title: Improvements in or relating to automatically adjusting force transmitting links
IPC: F16D65/54
Filed: 1944-02-18
Abstract: 577,339. Links; operating clutches. AUTOMOTIVE PRODUCTS CO., Ltd., and BROCK, W. H. J. Feb. 18, 1944, No. 3088. [Classes 80 (i) and 80 (iii)] [Also in Group XXXIV] Consists in an automatically adjustable link for transmitting force applied to a pedal, band lever or the like, particularly in the actuation of clutches and brakes, the link adjusting itself each time the clutch or brake is operated so as to take up wear and provide a predetermined clearance when the actuating mechanism is inoperative. As applied to the actuation of a clutch, a driving shaft 11 carries a disc 15 with which rotates a pressure plate 17 loaded by springs 20 to grip a clutch disc 22 on a driven shaft 12. The clutch is released by levers 23 which engage the plate 17, are pivoted at 24 and are connected at their inner ends to a release ring 26 adapted to be actuated by the lever 13 through self-adjusting link 27. This comprises telescopic members 32, 33 of which 33 is urged to the left by a spring 34 extending between a collar 35 and a fixed anchorage 36. The lever 13 is normally urged by a spring 37 towards a stop 38. The left-hand end of the member 32 is enlarged to receive a ring 40 having a pair of frusto-conical surfaces 41, 42 engaged by rows of balls 43, 44 to form main and auxiliary clutch devices respectively. The action of the balls is controlled by a releasing member 45, freely slidable on the member 33, and having holes 46 within which the balls 43 fit without play, and larger holes or slots 47 in which the balls 44 may move a short distance axially but are normally urged to the left by a light spring 48. The releasing member is formed with a flange 30 adapted to engage a fixed stop 31 and it has an annular seal 49 to keep out dirt &c. The flange is urged towards the member 32 by a tension spring 50 incorporated in a concertina boot 51. Thus the spring 50 acts to maintain the clutch 41, 43 in action provided the flange 30 is free of the stop 31. The operation is as follows:- When the clutch is disengaged, the link 27 is transmitting thrust and the parts are in the positions shown in Fig. 2. When the lever 13 is released the link 27 first moves to the right and when the lever reaches a predetermined position near the stop 38, the flange 30 engages the stop 31 so that further movement of lever 13 puts the clutch 41, 43 out of action to free the member 33. If at this stage the clutch is not completely engaged, say owing to wear, the springs 20 will complete the engagement, the ring 26 and member 29 on rod 33 being moved to the right. It is, however, undesirable for the members 26, 29 to remain in contact and therefore the final movement of lever 13 is arranged to separate these members. This is effected by the auxiliary clutch 42, 44 which comes into action to re-connect the members 32, 33 and drag the latter along slightly. When lever 13 is again actuated to disengage the clutch. the initial movement .brings the balls 44 back to the left-hand ends of their slots to disengage the member 33 to allow it to move under the action of the spring 34 to bring the members 26, 29 into contact. Thereafter the main clutch 41, 43 is in action to transmit force from lever 13 to plate 17. In a modification, the link 27 operates in tension, the lever 13 being of the first order and the frustoconical surfaces 41, 42 being reversed. In a further modification, Fig. 5, where automatic compensation is only required in one direction, the link 27b is in compression, the clutch lever 13 and the clutch 10 being shown diagrammatically to a smaller scale. The member 32 has a socket 59 to receive a spigot 60 of a cup-shaped member 61 which has an internal frusto-conical surface 41 between which and the member 33 are balls 43 fitting snugly in holes 46 in a releasing member 45. A light spring 34b acts between a flange 62 on member 33 and the releasing member 45, a flange 30 on which is adapted to co-act with the stop 31. The auxiliary clutch consists of a ring 63 of fibrous or like material disposed within the socket 60 and clamped between a shoulder 64 and a conical surface 65 so as to press inwards on the member 33.