Suspension switch with gear segment slider and operating force regulating contact operating cams

Claim 1

A suspension switch, for controlling electric motors driving hoisting gear, having an ''''OFF'''' switching position and plural sucessive ''''ON'''' switching positions, selected by actuation of a switch slider, said switch comprising, in coMbination, a rotatably mounted carrier shaft; a switch slider operable to rotate said shaft; plural cam discs of different cam shapes, fixed to said shaft for angular displacement as a unit therewith; respective spring-biased rollers cooperable with each cam disc; each cam disc having a respective cam track formed with at least one pair of symmetrically located substantially arcuate contact making surfaces and at least one pair of symmetrically located contact breaking surfaces engageable by said rollers to actuate circuit closers, all the contact making surfaces being at the same first spacing from the axis of said shaft and all the contact breaking surfaces being at the same different second spacing from the axis of said shaft and each cam track having roller abutting surfaces, of selected degrees of slope, interconnecting adjacent contact making and contact breaking surfaces and regulating the force required to operate the switch between contact making and contact breaking positions; and respective circuit closers operable by each roller to open and close motor energizing circuits in accordance with movement of said switch slider; the contact breaking surfaces of at least one cam being joined to the contact making surfaces thereof by abrupt roller abutting surfaces extending steeply in a nearly radial direction; the cam tracks of at least certain of the cams having symmetrically located relatively deep and narrow roller engaging notches between adjacent contact breaking surfaces releasably restraining movement of the switch between two successive operating positions.