GB1293679A - Disc brake caliper movement control - Google Patents

Abstract

1293679 Spot-type disc brakes; retractors; slack-adjusters AIRHEART PRODUCTS Inc 27 Nov 1970 [8 Dec 1969] 56561/70 Heading F2E A spot-type disc brake including a caliper slidable on rods 50 fixed to a non-rotary torque arm structure 51, Fig. 1, has actuators 70, 71, for applying the directly-operated pads, disposed inwardly of the rods 50; retraction is by a Belleville spring on each rod, and slackadjusting is provided for by a drag ring frictionally gripping each rod, the friction being overcome to move the drag ring along the rod only when caliper movement becomes excessive as a result of wear. As shown, the brake assembly comprises the floating caliper 46 mounted on and slidable along two rods 50, Fig. 1, each rod being connected by a pin 55, Fig. 4, to a torque arm 51, Figs. 1 and 4, the torque arms being connected in turn to an axle flange 54, Figs. 1 and 2, projecting from a fixed axle 49. The right hand end of the caliper, in Fig. 2, (which is the left-hand end in Fig. 4, Fig. 4 being an elevation of the far side of Fig. 2), has secured in it, by means not shown, a brake pad 47 for engagement with face 45a of disc 45, the disc being secured at 44 to a rotary shaft 41 to which a vehicle wheel 40 is also secured at 42, Fig. 2 In operation when two pads 72, Fig. 2, are applied by two hydraulic actuators 71, Fig. 1, caliper 46 is moved by reaction in direction 48 to the "apply" position shown in Fig. 4. Such movement is opposed by a retractor comprising a Belleville washer 58 located between two washers 61, 62, of which washer 62 is retained by a drag ring 60 which tightly grips the rod 50. On brake release, Belleville washer 58 returns caliper 46 to its former position. Slack-adjusting.-As pad 47 wears, caliper 46 is impelled further to the right, in Fig. 4, on brake application, until the frictional resistance between drag ring 60 and rod 50 is overcome, whereupon ring 60 is forceibly shifted to a new position. A protective part 66 is secured, around the end of rod 50, to caliper 46 at 67, and contacts ring 60 in the "release" position. Fig. 5 (not shown), depicts wholly diagrammatically, a complete brake in cross-section with a single cylinder cavity containing a single piston, to which a pad corresponding to pads 72 is secured. The piston rod protrudes through the cavity (provided wholly in the caliper) to the exterior; a retractor spring is located about the protruding part of the piston rod and acts between the face of the caliper and a washer secured to the rod. This spring has to allow for the sum of two retraction distances one appropriate to the caliper, the other appropriate to the piston.