| 摘要 |
1,217,384. Brakes. GIRLING Ltd. 5 May, 1969 [9 May, 1968], No. 21936/68. Heading F2E. A mechanical actuating linkage for the brake shoes in a drum brake comprises a pair of levers 14 or a lever and a roller having mutually abutting curved surfaces 22 which roll against each other to produce an expansion against support pivots 20 on abutments 10 on the shoes when drawn down, as shown in Fig. 3, by rod 24 and links 28. As shown in Fig. 5, the brake shoes are normally actuated by cylinder 38, but the present auxiliary mechanical operator is located within it to act on the same shoes. In the form shown in Fig. 6 the cylinder 38 lies within the mechanical actuator which in this form has only a single arm 46, pivoted at 50 as before but rolling against a roller 58 instead of another arm as above, Fig. 7. In a further modification using two arms, Figs. 10, 11, a strip 124 is used to draw the arms down, and a covering saddle 136 is also provided. Metal fatigue may be reduced by facing the rolling surfaces with additional spring strips 160, Fig. 13. |
