GB930576A - Improvements to automatic adjusting devices for brake linkage systems - Google Patents

Abstract

930,576. Automatic brake clearance adjusters. SVENSKA A.B. BROMSREGULATOR. Dec. 16, 1961, No. 45178/61. Class 103 (1). A brake clearance adjuster, particularly for use in railway vehicles, comprises a nut 31 and screw 34, the nut being freely rotatable on the reversible screw-thread in the direction of unscrewing to increase the clearance and being positively rotated in the direction of screwing-up to take up clearance. The nut 31 is rotated by an adjuster casing 35 set in oscillation by a rocking angle lever 60 which traverses a slideway piece 63 under the thrust of the brake cylinder, the connection between the casing 35 and the lever 60 being a hinged rod 40. The lever 60 and slideway piece 63 are so designed that one oscillation of the casing is effected during both the brake application and release strokes. The lever 60 is pivotally mounted on a pin 8, a roller of which slides in a slot 62 of the slideway piece 63. Lever 60 possesses three thrust faces which cooperate with rollers 69, adjustable in position along a slot, and 70 of the slideway piece 63. A coupling sleeve connected to nut 31 and a circlip 53 of casing 35 are adapted to frictionally engage a drive ring 50 in part of the operative cycle of the adjuster. The drive ring 50 is actuated by a coiled spring 51 attached at one end to the casing 35 by friction and at the other to the drive ring 50 allowing free rotation of the latter in the direction of unscrewing. A compression spring 46 is positioned between a shoulder of a hollow shaft 48 connected to sleeve 52 and a thrust bearing acting against the drive ring 50. A guide sleeve pivotally connected to a beam lever 7 possesses a thread 44 which co-operates with a thread 43 of the casing. A motion discriminator in the form of a butt coiled spring 88 in frictional contact within sleeve 90 of guide sleeve 5, engages in an opening 86 of drive ring 50 so that rotation in the unscrewing direction of the nut and screw is prevented. If the clearante is too small, during the brake application all components of the adjuster become stationary in translation except for guide sleeve 5. Thread 44 engages thread 43, drive ring 50 being drawn out of contact with coupling sleeve 52 by circlip 53 effecting the unscrewing of the nut and screw by virtue of their reversibility and the braking force. The unscrewing continues until nut 49 frictionally engages ring 47. If the clearance is too large, however, on release of the brakes, the parts will move towards their inoperative positions until drive ring 50 frictionally engages coupling sleeve 52. The casing then performs the screwing up portion of its oscillation which through spring 51 is communicated to drive ring 50 and thence to the nut 31.