GB493748A - Improvements in or relating to friction clutches - Google Patents

Abstract

493,748. Friction clutches. BORG & BECK CO., Ltd. March 16, 1938, No. 8188. Convention date, Aug. 26, 1937. [Class 80 (ii)] In a plate clutch, engaging pressure is transmitted to the pressure plate 4 from springs 15 housed in the driving flywheel 2 through force-multiplying levers 14, each lever being pivotally mounted on a bracket 13 secured to the flywheel and being subjected to the pressure of the spring 15 at a point radially outwards from its fulcrum, while the lever is in engagement with the pressure plate, through a roller 27, at a point radially inwards from its fulcrum. The inner ends of the levers co-operate with a sleeve 45 which can be moved to disengage the clutch, the plate 4 being urged to disengaged position by light springs 6. Each bracket 13 is of U-shape, being secured to the flywheel by a single screw 16 and positioned by a projection 17 engaging a recess 18. The sides of the brackets engage between lugs 47 on the plate 4, so as to provide a driving connection between the latter and the flywheel. Each bracket 13 carries a pair of spaced levers 14, the common pivot pin 22, fitted with a spacing sleeve 24, engaging in enlarged holes 19 in the sides of the bracket so as to afford a rolling fulcrum. A single roller 27 co-operates with each pair of levers, being positioned in recesses 26 in the levers and engaging a flat surface 28 on the plate 4. The lugs 47 prevent endwise displacement both of the rollers 27 and of the pins 22. A pair of springs 15 associated with each bracket transmit pressure to the pair of levers through a common strut member 37. The latter passes through slots 38 in the sides of the bracket, so as to limit its movement, and has an enlarged part 42 serving to space the levers and to prevent endwise displacement of the member 37. In a modification, stamped sheet-metal levers are employed, each lever co-operating directly with a single spring and having a pivot pin engaging an enlarged hole in a lug projecting through a slot in the lever from an individual bracket secured to the flywheel. In this form, the driving connection between the pressure plate and the flywheel is afforded by a radial projection on the former engaging a groove in the latter.