Abstract: A pillow core (1) is made from a foamed plastics material which is softly resilient, and has its upper thickness formed with upright parallel ribs (5) spaced from one another by slots of elongated cross-section. The ribs have their upper surfaces attached to the underside of a porous web (3) which is soft and flexible but relatively inextensible in its own plane. The lower thickness of the core (1) is formed with cylindrical sockets (11) containing removable plugs (14) of foamed plastics material removable from their sockets through respective slits (12) formed in the underside of the core. The upper thickness of the core gives the pillow surface a soft plush feel, and the plugs are selectively removable to alter the resistance to compression of the pillow.

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.

Abstract: A torque limiting mechanism has two locking members (1 31, 137) designed to be incapable of transmitting drive between them but having meshing spiral teeth (132, 138). The members are in a rotatable frame (127) and are respectively driven by radially toothed gears (128, 124) having an idler gear (125) between them. One radially toothed gear (124) is splined (at 123) to a section of a drive shaft (110) of reduced diameter so that it twists in torsion when an input driving torque is applied to the shaft (110). Gear lash exists between the radially toothed gears (124, 125 and 128) which is overcome by the twist of the shaft (110) if the applied torque is big enough. When this occurs, synchronous drive from the input shaft (110) is applied to both locking members (131, 137) so that they rotate together. The applied torque necessary to achieve this is determined by the position of one gear (124) on the spline (123) and this is controlled by a lever (114).