GB293382A - Brakes - Google Patents

Abstract

293,382. Backinton, G. W., (Assignee of Tatter, J. W.). July 5, 1927, [Convention datel. Band; compensating for wear; covers and protectors for brakes.-Mechanism for compensating for wear in a band brake comprises a ratchet disc device whereby the relative angular relationship between a lever and a shaft operated thereby is adjusted. The band is applied to the drum by the engagement with fixed cam members of cam members rotatable with and slidable on the shaft. The brake drum 27 is shown as mounted upon the transmission shaft of a motor tractor and is enclosed in a casing 35 bolted to the body portion of the vehicle. A shaft 34 journaled in the casing 35 has mounted thereon lugs 32, 33 connected by pins 30, 31 to the ends of the brake band 40 which may taper in thickness from the middle part towards its ends. As described in Specification 317,575 a radial pin 42 attached to the middle point of the band passes through a, slot 43 in the casing to prevent lateral displacement of the band. Each lug 32, 33 is provided with a pair of fingers 50 - - 53 which slidably engage in V-shaped grooves formed in the other to prevent rooking movement of the lugs about the pins 30, 31. Sleeves 61, 62 rotatable with and slidable on the shaft 34 abut against the lugs 32, 33 and have cam faces in contact with corresponding cam faces on fixed sleeves 68, 69. A disc 99 secured to the shaft 34 is provided with oppositely inclined ratchet teeth with which ratchet teeth on two levers 95, 102 respectively engage. The teeth are held in engagement by springs disposed in bosses 85, 105 and arranged to press axially on the levers which are freely mounted on the shaft. The lever 95 carries a projection 127, Fig. 6, against which the lever 102 normally abuts under the influence of a spring 124 disposed between the levers. To apply the brake, the lever 102 is turned to the left, Fig. 6, the shaft 34 being thereby partly rotated by the engagement of the ratchet teeth and the sleeves 61, 62 and lugs 32, 33 moved towards each other by the action of the cam surfaces. The levers 95, 102 move together until, if the movement is excessive, the lever 95 engages stop 131 when further movement causes the ratchet disc 99 to slip a tooth with respect to this lever and during the return movement the lever 102 slips a tooth with respect to the disc 99, thus taking up the excessive slack in the band 40.