GB367432A - Improvements in and connected with automatic clutch devices - Google Patents

Abstract

367,432. Friction clutches. STONE & CO., Ltd., J., Deptford, London, and HATCHER, E. C., Instow, Woodside Road, Northwood, Middlesex. Nov. 20, 1930, No. 34954. [Class 80 (ii).] In a centrifugal clutch, particularly for a drive from a vehicle axle, such as is described in Specification 339,978, [Class 80 (ii), Gearing, Variable-speed &c.], wherein centrifugal clutch shoes 1 are subjected to a camming action by the driving member 6 to obtain a quicker and greater grip, the camming action is opposed, to make it more gradual, by a resilient resistance such as a spring or a counteracting centrifugal force. Means for permanently disengaging the clutch, and a thermally actuated safety device may additionally be provided. In the reversible clutch shown, shoes 1, loaded inwards by springs (not shown) are pressed outwards, after initial centrifugal engagement with a driven drum 11, by cams 13 on a driving member 6 engaging cam surfaces 4 on the shoes. The resilient resistance comprises springs 3, Fig. 1, carried in grooves in the shoes and abutting against stops 5 on the driver and 8 in the shoes. The springs surround rods 14 fast on the stops 5 but free to slide through washers 15 into a slot in the stop 8. The springs also facilitate disengagement of the shoes from the drum 11. In a modification there are C springs projecting from transverse slots in the cams 13 and pushed back into the slots by the clutch shoes. Alternatively the C springs may be mounted at one or both ends of the cams 13. The modification shown in Fig. 4 utilizes a counteracting centrifugal mass 18 guided radially in the driver 6 and moved inwards by an internal cam surface 20 on the shoe 1. In order to allow permanent disengagement of the clutch, such as when used for driving a generator supplying heating current, the clutch shoes may be provided with lateral projections which are obstructed from outward radial movement by stops carried on bolts movable into the obstructing position in arcuate slots in a side cover part. To prevent damage due to excessive heating, there may be a layer of fusible alloy between the shoes and their friction linings, the alloy being riveted to the lining and having a tongue and groove connection with the cast-iron shoe. According to the Provisional Specification the shoes may be locked out of engagement by a screw on the flange which may register with a hole or slot in the shoe.