GB846555A - Improvements in or connected with the mechanical brake systems of winding engines, haulages, and other rotating machines - Google Patents

Abstract

846,555. Fluid pressure-operated brakes. ROBEY & CO. Ltd., and CROMPTON, A. Feb. 27, 1958 [Dec. 5, 1956; Oct. 23, 1957], Nos. 37173/56 and 33062/57. Class 103 (1). A braking system has one or more pairs of shoes disposed exteriorally and diametrically on either side of a brake drum, the shoes being carried by sliding elements guided in a frame for radial movement relative to the drum, the shoes being urged toward the drum by means acting on, and disposed symmetrically with, the sliding elements, and moved away from the drum by fluid pressure means. Each element 4 carrying a shoe 2 is slidable in part circular guides 7 in a fixed rigid frame 1, compression springs 8 being interposed between the element 4 and a cover 9 slidably secured on bolts 10 to frame 1; cylinders 5, 12 fixed to frame 1 have rams 6, 13 abutting the element 4 and cover 9 respectively, and screws 11 limit movement of shoe 2 toward frame 1 to adjust for wear. Initially hydraulic pressure is admitted to cylinder 12 to move cover 9 and compress springs 8 to a required degree determined by the hydraulic pressure, the bolts 10 then being adjusted to hold the springs 8 at this compression and the pressure is relieved from cylinder 12. The brake is then normally applied by the springs and is released by admitting pressure fluid to the cylinder 5 to compress springs 8 through ram 6 and element 4. In Fig. 3, a double cylinder and ram device secured to the frame 1 has one ram 17, 18 holding the brake applied and a second ram 15, 16 in which the first slides, to which hydraulic pressure is admitted capable of overcoming the first ram to release the brakes, an extension of the piston 16 forming the cylinder 17; should the pressure in the ram 17, 18 fail then the brakes are applied by a weight 25 through levers 24a, 24 and cams 23, 23a, the weight normally being held up by the pressure from the ram 17, 18 acting on plunger 21. In Fig. 5, not shown, the double cylinder arrangement of Fig. 3 is applied to a unit of the type shown in Fig. 1, the springs applying the brakes in an emergency on failure of pressure in the first ram. In Fig. 7, not shown, is a system employing a series of pairs of diametrically-opposed brake units disposed at intervals along a brake winding drum, all connected to an operating valve which can be operated electrically, mechanically or hydraulically in an emergency, the pressure being supplied from a pump through a non-return valve from a reservoir, a separate emergency valve may be included. Whilst in Fig. 8, not shown, the pairs of brake units are divided into two sets, one for normal use and the other for emergency, a valve normally supplying fluid to the normal brakes being automatically switched to apply these brakes in an emergency but is prevented from operating if the emergency brakes are already applied, the emergency brakes being operated at will by an operator. Specifications 540,921 and 633,129 are referred to.