Abstract: A cylindrical oil-filled casing (2, 3, 5) has an input shaft (12) on which are mounted a pair of braking rings (17, 26) which are allowed limited axial and circumferential movement with respect to one another. The ring (26) is driven by the shaft and drives the other ring (17) through a circle of angularly-spaced, spring-biassed balls (28) mounted in tear-drop shaped recesses in the opposed faces of the rings (17, 26). Each ring has a frusto-conical braking rim extending parallel to a frusto-conical braking surface (8, 9) provided on the casing part (5). The rims of the rings (17, 26) have angularly-spaced, shallow, chordal segments removed to provide recesses which, during rotation of the shaft (12), pump oil between the braking surfaces of the rings and the casing, to form hydraulic cushions therebetween. Reversal of the shaft torque causes the balls (28) to force the rings (17, 26) apart and into braking engagement with the casing to check rotation of the shaft.

Abstract: A drive mechanism has two parallel shafts (2,3) provided with overlapping circumferentially-extending spiral teeth (4,5) of the same hand. The shape and positioning of the teeth is such that when one of the shafts is rotated, the steep flank surfaces (7,9) of its teeth engage the steep flank surfaces (9,7) of the teeth of the other shaft and force it to rotate in the same direction. Unidirectional drive may be obtained by providing each tooth with a gently sloping flank surface (8,10) on one side. The engagement of the gently sloping flank surfaces prevents rotation of the shafts if the driving torque is reversed.

Abstract: The mechanism 204 prevents reversal of the torque of shaft 203 by braking two disc members 206, 207 against braking surfaces of a casing 205. Under normal operating conditions the member 206 is turned by a motor 202 controlling a load 200 in a direction which causes its drive to be transmitted through balls 221 to the member 207. In this condition minimal braking occurs. If the direction of the shaft 203 is reversed, the balls 221 force apart contiguous camming surfaces on the disc members so that their braking surfaces engage the casing to brake the shaft 203. Controlled manual release of the load under braked conditions is permitted by turning a handle 224 driving a shaft 210 which turns the member 207. Minimal braking friction during normal operations is reduced still further by creating a cushion of oil between the braking surfaces, the oil being provided by a gear pump 216 driven off the shaft 210.

Abstract: A differential mechanism is provided with two output shafts 202 and 204 coaxially arranged and extending to wheels 203 and 205 of a vehicle. The differential is provided with a pair of connected discs 221, 209, the disc 209 being rotated about the common axis of the shafts 204, 202 by a drive shaft 206 and a pinion. An intermediate shaft 211 is eccentrically positioned between the two discs 209, 221 and is formed with a circumferentially extending spiral tooth 241. The tooth 241 engages a driving gear 217 fixed to the shaft 202 at one end-portion and the other end-portion of the member 240 provides a member in mesh with the second member 216 fixed to the shaft 204. The teeth of the members 216 and 240 are shaped and positioned so that drive between them is inefficient but they will translate over one another if the member 216 is rotated in the same direction and at the same speed as the member 240.