GB336560A - Improvements in and relating to friction clutches - Google Patents

Abstract

336,560. Maina, J., and Davidson's Patents, Ltd. July 6, 1929. Clutches, friction and ratchet; clutches allowing slip.-In power-transmission mechanism comprising a clutch between a driving or driven shaft and a member permanently geared thereto by helically-toothed wheels, wherein the axial reaction of the gearing automatically engages and disengages friction elements associated with the fast-running shaft or member, there is provided a spring or other axial force which either must be overcome before the clutch can engage or disengage, or acts to press the surfaces into light initial engagement. Fig. 1 shows a modification of the clutch shown in Fig. 7 of Specification 308,451, wherein a light compression spring 50 is interposed between the clutch members 30, 35, rotation of the driving-shaft 31 as shown by the arrow merely turning the member 30 idly by the toothed wheels 32, 33, 37, 38, until, due to the drag of vanes 51 in oil or other means, the reaction of the helical wheels 37, 38 overcomes the spring to clutch the shafts 31, 36 solid. If the spring &c. acts reversely, the clutch disengages on excessive torque, the vanes &c. being unnecessary. In a modification, a motor-vehicle engine flywheel b is formed with a drum a having a clutch surface h and internal helical teeth c, with which mesh planets d on a carrier e on the gearbox shaft #, the sun-wheel g being formed on a loose sleeve j. A clutch plate i, slidable on the sleeve j, is thrust against the surface h by a presser-plate k and springs m with sufficient force to provide for engine-braking, this force being augmented on forward drive by levers n actuated by movement of the sleeve j to the right due to the helical-tooth reaction. On light load, the plate k can be withdrawn by connections (not shown) to the usual pedal. In a further modification, Fig. 3 (not shown), the plate k is normally held out of action by springs, but is engaged by cam-levers so shaped as to thrust it into action on movement of the sleeve j to the right or left, i.e., when the engine drives or is overrun.