| 摘要 |
An internal shoe drum brake comprises a pair of brake shoes, return spring means, service brake means, manually actuated auxiliary brake means including an actuating lever with a finger and an adjustable, in length, strut. The strut includes relatively rotatable screw threaded parts, i.e., a screw-threaded spindle slidably received in a tube member, a ratchet wheel in threaded engagement with the spindle and stopper held in yielding contact with the wheel, so that the strut is adjustable in length to adjust shoe clearances, a pivoted adjusting lever with a pawl tooth for effecting rotation of the ratchet wheel relative to the spindle upon brake application by the auxiliary brake means, and a prestressed coil torsion spring arranged to transmit forces to urge the adjusting lever in a direction to effect shoe clearance adjustment as required in response to operation of the auxiliary brake means. |
