GB282261A - Improvements in vehicle brake mechanism - Google Patents

Abstract

282,261. Clark, D'A. M., (Bendix Brake Co.). April 12, 1927. Blocks and shoes acting on drums; compensating for wear.-Relates to brakes more particularly of the internal expanding type in which the friction member anchors at one end or the other according to the direction of rotation of the drum. In the form shown a pair of shoes 60, 62, Fig. 4, hinged together at one end 68 are provided at the other ends each with a roller 106 engaged by a floating cam expander 116. The cam, Fig. 5, comprises a pair of plates or stampings 116 each having an arm connected by a pin 120 to an arm 122 secured to an operating shaft 52 which passes freely through openings in the cam members 116 so as to permit the floating action thereof. A pair of rollers 106 are provided one on each side of the end of each shoe for engagement with the respective cam 116. Each pair of rollers is mounted on a pivot 104, Fig. 6, passing through the end of the shoe. The pivots extend laterally beyond the rollers so that they may engage in slots formed in a pair of spaced plates 108, 110 secured by bolts 112 to the fixed backing plate 30 of the brake. Endwise movement of the pivots is prevented by providing the centre part of larger diameter which abuts on the rollers 106 as shown in Fig. 6. Each shoe 60, 62 has a central stiffening web slotted to form tongues welded or otherwise secured to an outer band which carries the brake lining. The shoes are hinged together at the ends by means which permit of their adjustment to take up wear of the brake lining. These means comprise a pair of members 66 each formed with a worm which engages teeth formed on the edges of slots cut in the ends of the shoes. Each member 66 'has a hemispherical socket seated upon a boss formed on a member 68 comprising two parts welded together and having polygonal flanges embracing the heads of the members 66 which may thus be turned by a tool inserted in holes in the flanges. Patches or stampings 72 spot welded along one edge to the shoes are clamped by fastenings 76 against the opposite sides of members 66 to hold them from unintentional movement. A spring 78 holds the parts 66, 68 in contact. Steadying devices for the shoes comprise a pair of spring pressed washers 80, Fig. 7, on a pin 84 secured to the backing plate 30. In addition there is also provided for the shoe 60 a device for automatically adjusting the clearance comprising an arm 90 frictionally secured to the shoe by a bolt 96 and having a slot through which the pin 84 passes. The arrangement is such that if in the application of the brake the shoe moves outwardly more than a predetermined amount determined by the width of the slot 94, the arm 90 is turned and the clearance in release thereby reduced. A spring 78 returns the shoe 60. Main return springs 114 are also provided. Force-transmitting mechanism.-In the case of a front wheel brake, the arm 50, Fig. 3, of the brake is operated by a link 48 connected thereto and to one arm of a lever 44, Fig. 2, mounted on the .axle 22. The link 48 has an upturned end 46 which passes through the end of the lever 44 the end 46 being disposed in the steering axis of the wheel when the brake is applied. Rattling is prevented by a spring 54.