Patent GB-431854-A (GB)
Title: Improvements in brakes
IPC: F16D65/09
Filed: 1933-12-09
Abstract: 431,854. Brakes. BENDIX AVIATION CORPORATION, 105, West Adams Street, Chicago, U.S.A. Dec. 9, 1933, No. 34723. Convention date, Feb. 20. [Class 103 (i)] A brake comprising floating brake shoes 224, 226 connected by adjusting means 230 and provided with openings 258 by means of which the shoes abut against fixed anchors 260, an operating lever 240 being pivoted at 42 on the unconnected end of the shoe 224 and connected by an adjustable compression link 248 with the other brake shoe 226. The adjusting means 230 comprises two parts threadedly engaging one another, one part swivelling in a socket 228 engaging shoe 224. A brake shoe return spring 236 engages a toothed collar 234 to yieldingly lock the adjustment. The link 248 comprises a similar arrangement. Each anchor 260 has a flat surface engaging a straight or slightly curved edge of the opening 258. The shoes are urged against flattened bosses on the back plate by spring steady rests 264. Positioning devices 272 comprise rollers engaging the shoe rim and mounted on an eccentric portion of an angularly adjustable stem clamped to the back plate. A modified positioning device comprises a right-angled stop adjustable in a slot. A further arrangement comprises an eccentric roller engaging the shoe rim and carried on a stem engaging the shoe web. The roller is rotated by gearing from outside the brake. A modified adjusting device comprises an adjusting member having oppositely extending right and left hand threaded stems 314, Fig. 9 received in threaded openings in transverse pivots 312 in the shoe ends. A central worm wheel 316 is engaged by a worm 318 adjustable from outside the brake, and mounted in plates 320 supported by slots on the ends of pivots 312. Plates 320 have lugs 332 engaging between spring plungers 334 mounted in sockets 338 fixed to back plate and acting as a centring device. In a modification the centring device is omitted and pivots 312 are extended to slide on the back plate. A brake drum comprises a stamping 292 in which is secured a shell 296 containing a centrifugally-cast iron liner 298. A flange 300 on the drum coacts with a flange 302 on the back plate and shell 296 has a rib 304 to practically seal the drum. The Specification as open to inspection under Sect. 91 comprises also modified arrangements of operating levers, the compression link 248 having no provision for adjustment. Also a brake is shown in which the shoe anchors are carried on swinging links, and in a further arrangement the shoes are operated by a fluid pressure cylinder. In another brake the shoes are operated by a wedge mounted on a lever. In an automatic adjusting device Fig. 5 (Cancelled), the screwed adjusting means 102 is turned by a pawl 118 operated by a spring 124 when a bell crank 122 is moved away from it by a rod 108 connected to the shoe 22. This occurs when lost motion 112 is taken up when wear occurs. Movement of pawl 118 is limited by strips 124<2> and thus rendered uniform to prevent excessive adjustment. To prevent adjustment due to clearance occurring on heating of the brake a thermostatic bar operates a lever 130 having forked engagement with the pawl 118 to release the pawl on heating occurring. The shoes may be provided with stops at the operating ends on which they pivot when being adjusted. Transmission mechanism is shown operating on the lazy-tongs principle, the pedal and hand lever each operating foursided hinged members on a cross member which operates similar four-sided members connected to the brakes. In a modification the cables from the brakes are connected to links swinging on the chassis and connected by a short cable operated by a cross cable. This subject-matter does not appear in the Specification as accepted.