| 摘要 |
<p>1470114 Transmitting mechanism; slack adjusting LUIS ITURRIAGA NOTARIO 1 July 1974 [5 July 1973] 29081/74 Heading F2E A device for actuating brake shoes of heavy vehicles provided with pneumatic brake systems in which the path of travel of the piston or membrane driving device as well as the shoedrum distance should be maintained constant comprises a cam-shaft 1 having a brake-shoe actuating cam (not shown) and forming a solid part of at least one ratchet wheel 2 on which two fingers 3, 4, act, one finger, 3, being mounted on an actuating lever 5 which, in use, receives the thrust, in direction 14, of the piston or membrane, while the other finger, 4, is mounted on a spring-biased rocking lever 6. As shown, the actuating lever 5 is freely mounted on the cam-shaft 1, and movement of rocking lever 6 is limited by abutments 10 (invariant) and 11 (adjustable). In operation, when the shoes are not worn, actuating lever 5 rotates cam-shaft 1 in direction 12 by finger 3 and ratchet wheel 2, the latter urging finger 4 downwards against spring 22. On brake release, cam-shaft 1 and wheel 2 are restored by the brake pull-off springs (not shown) and lever 5 is restored by spring 15, to the position shown. When the shoes are worn a ratchet tooth moves past finger 4 during brake operation, and on brake release full restoration of wheel 2 is prevented by engagement of the radial side of a tooth with finger 4, and by stop 11. In view of the new position of wheel 2, finger 3 must jump a tooth on restoration of lever 5.</p> |
