Rotary vane machine with spring-biased vanes

Claim 1

A portable pneumatic hand tool, comprising a portable housing; a tool chuck mounted on said portable housing; a fluid motor in said portable housing and comprising a rotary outer component having an inner circumferential surface and a stationary inner component having an outer circumferential surface which is eccentrically surrounded by said inner circumferential surface, said outer component being rotatable relative to said inner component and being connected in motion-transmitting relationship with said tool chuck; at least two pairs of guide slots formed in said inner component and each having an outer end open at said outer circumferential surface and an inner end, the guide slots of each pair being diametrically opposite each other; at least two passages formed in said inner component and each communicating the inner end of one guide slot of a pair with the inner end of the other guide slot of the same pair; a sliding vane in each of said guide slots and having an inner edge face and an outer edge face; and means for mutually supporting the sliding vanes in each pair of guide slots for simultaneous sliding movement in the respective passage, comprising biasing means having opposite ends bearing upon said inner edge faces of the sliding vanes in each pair of guide slots and urging said outer edge faces apart from each other and into engagement with said inner circumferential surface, whereby low stressing of said biasing means is obtained.