Patent GB-1167748-A (GB)
Title: Improvements in and relating to Rotary Friction Clutches
IPC: G05G7/04
Filed: 1966-11-16
Abstract: 1,167,748. Clutch control. BORG-WARNER CORP. 16 Nov., 1966 [8 Dec., 1965], No. 51415/66. Heading F2L. In a control for a vehicle clutch wherein a driven plate 29 carries friction facings on spring cushions 34 (Figs. 2A, 2B, not shown) providing maximum cushion reaction force at full clutch engagement, and a presser plate 26 is axially movable to clamp the driven plate against a driving a flywheel 21 by a "remote" spring C, the latter comprises a V-forming pair of helical tension springs 58 chordally disposed with respect to the presser plate and having a resultant force directed generally perpendicular to and through the clutch axis, and a common force-transmitting two-ply sheet metal rocker member D-1 rockable about a fixed pivot D-2 interconnects the engaging spring C, a disengaging clutch pedal B and a lever system D-4 to the presser plate such that, to achieve a soft clutch pedal effort, as the clutch approaches the disengaged position the moment arms of the connections of the lever system D-4 and the spring C to the rocker member D-1 respectively increase to offset the usual drop-off in the reaction force from the cushions 34 and decrease to reduce the effectiveness of the force of the spring C. The clutch comprises a sheet metal cover plate 24 fast with the flywheel, and resilient tangential retraction straps 27 so drivingly connecting the presser plate to the cover plate that a presser plate retraction tendency remains in the straps even when the clutch is fully disengaged. The clutch internal actuation system comprises radial sheet-metal levers 42 having inner ends 42a engaging a thrust bearing assembly 43, outer ends fulcrumed on the cover plate 24 by struts (44) engaging coined seats in the cover plate and levers, and rounded intermediate portions engaging flat or embossed surfaces of the presser plate. U-shaped clips 48 retain the struts (44). A lever 50 having its inner end engaging the thrust bearing assembly 43 is fulcrumed on the clutch housing by a strut 51, and a retention spring (54) adjacent the strut 51 acts to aid clutch disengagement. The pedal B is connected to the rocker member D-1 by a cable 73 housed in a casing 74 having a low friction material liner and one terminal end 74a secured by a ferrule 75 to the clutch housing. A rolling pivotal connection between the cable 73 and the rocker member D-1 comprises an oblong or D-shaped opening 77 in a cable-connected blade 76b engaging a pin 78 of the rocker member. The springs 58 are hooked at one end in holes 59 in the clutch housing, and at their other end to pins 60 of the rocker member D-1, hooks of the spring engaged by the pin having flats (63) to provide a rolling connection. A link 69 connecting the rocker member D-1 to the lever 50 comprises inter-threaded members (87), (86) respectively engaging the outer end of the lever 50 and having a D-shaped opening (71) rollingly engaging a pin 72 of the rocker member D-1, the disposition of the link 69 being such that force is transmitted therethrough substantially parallel to the clutch axis. For automatic wear adjustment, a helical spring (88) wrapped around the member (87) has an outwardly extending end (88a) engageable by fingers (90) (91) of the rocker member D-1, such that when wear occurs the spring is unloosened by the finger (90) and, on disengagement, the finger (91) tightens the spring and screws the member (87) out of the member (86). Whilst the pedal B may be held in its raised position by the force of the spring C, a retention spring may be employed to prevent pedal float or bounce.