Improvements in and relating to Wedge Type Actuators for Vehicle Brakes

摘要

1,151,352. Brake actuators. GIRLING Ltd. 27 May, 1966 [9 June, 1965; 8 July, 1965], Nos. 24334/65 and 28911/65. Heading F2E. In a wedge brake actuator comprising a pair of thrust members 120, 122 in opposed bores of a housing 112, a plunger 124 intermediate and movable transverse to the thrust members, a wedge member 156 carried by and slidably movable transverse to the plunger axis, and rollers 146 interposed co-operating inclined faces on the thrust and wedge members, a cage 136 carries the rollers and maintains their axes parallel and in a plane perpendicular to the plunger axis, a mechanical connection being provided between the cage and wedge member to restrict relative movement therebetween wholly to movement in a direction of plunger movement. The cage, which is W-shaped, and wedge member are located in a transverse bore in the plunger, which is actuated by a spring- loaded pull-rod 132. The cage is provided with rectangular apertures 139 in each of its arms 136 and a key 152 extends through the apertures to transverse channels in the plunger and has a projection 150 fitting in a groove in the wedge member. By virtue of the key and its engagement with the plunger and apertures 139, the cage is slidable relative to the plunger in a direction parallel to the plunger axis and in a direction parallel to the axes of the thrust members and the wedge member is constrained to sliding movement relative to the cage in a direction parallel to the plunger axis and perpendicular to the axes of the thrust members. Thus the rollers are always aligned with their axes maintained in a plane parallel to the axes of the thrust members, even if one of the thrust members become seized or deliberately fixed, Fig. 4 (not shown). In a modified embodiment, Figs. 6 and 7 (not shown), the key and wedge member form a unitary member 200, the upper end of the housing is closed by a cap having a bore constituting a guide for the upper end of the plunger.