Patent GB-1422502-A (GB)
Title: Multiple disc brake having an automatic brake adjusting and reset apparatus
IPC: F16D65/54
Filed: 1974-06-14
Abstract: 1422502 Wear adjustment; multidisc brakes; brake cylinders BENDIX CORP 14 June 1974 [9 Aug 1973] 26420/74 Headings F2E and F2F  A multiple disc brake includes a plurality of circumferentially spaced-apart brake adjusting and reset devices 54 contained in axially extending openings 56 in a brake carrier 20, each of the devices 54 comprising a rod 62 fixedly secured to an annular pressure plate 40, inner and outer radially deformable tubular members 58, 60, an annular member 72 secured to the rod 62 for deforming the member 58 during wear adjustment until the member 72 engages an annular crimp 78 in member 58 and a ring 82 held between members 58, 60 for deforming member 60 during wear adjustment subsequent to the member 72 engaging crimp 78. The pressure plate 40 which carries friction material 42 acts to apply the brake when pistons 38 in spaced cavities 22 in the carrier 20 are pressurized. Each piston 38 comprises two sections 44, 46-the piston section 44 is slidably carried on a fixed post 48 having a stop 50 engaged by section 44 to limit travel thereof and the section 46 is slidably carried by section 44 and pressurized by fluid passing between a reduced diameter section 52 of post 48 and the section 44 when the latter engages stop 50. Movement of pressure plate 40 compresses rotor members 30 and stator members 34 together. The stator members 34 have a friction lining 36, and a backing plate 26 of a torque tube 24 has a friction lining 27. The inner tubular member 58 of each device may be preformed to provide a starting position from which member 72 is actuated axially through member 58, while a flange 80 on member 58 bears on ring 82 which in turn bears against a portion 84 of member 60. The tubular member 60 is flared outwardly to provide an annular flange 86 which bears against a retaining member 88 slidably carried in a recess 90 and engageable with a first stop defined by a shoulder 92 or a second stop defined by a snap ring 94, the member 88 being urged against ring 94 by a spring 98. The member 88 may be eliminated by extending flange 86 radially outwardly. The tubular members 58, 60 may be formed of any suitable deformable material, e.g. aluminium, copper, nickel and their inner walls may be coated with a material to reduce frictional resistance to movement of members 72, 82 through members 58, 60. When the disc brake is actuated by pressurizing pistons 38 the pressure plate 40 is moved against the resistance of springs 98, and the members 58, 60 move with the pressure plate 40 until member 88 engages shoulder 92 at which position the brake is assumed to be fully engaged. However if the friction linings 27, 36, 42 have worn the member 88 will engage shoulder 92 but the rod 62 will continue to move with pressure plate 40 so that member 72 deforms member 58 as it moves therethrough to the extent dictated by movement of plate 40 whereupon member 72 is frictionally secured relative to tubular member 58. Upon brake release the plate 40 and members 58, 60 are retracted by springs 98 to the extent established by engagement of retaining member 88 with snap ring 94 thereby providing the brake running clearance. As lining wear continues member 72 will eventually engage crimp 78 and further compensation for wear takes place by deformation of tubular member 60 by ring 82. The outer tubular member 60 may also be crimped at one end.