| 摘要 |
<p>An elevator car braking system in which a pair of brake shoes engage and grip the hoisting ropes, part of the hoisting apparatus or the car guide rails when compressed springs, which are normally held in a compressed state by an electrically operable locking assembly, are released. The springs are compressible by a fluid operable piston and cylinder assembly. The springs move a cam follower, linked to one of the shoes, along cam surfaces shaped and disposed to cause the cam follower to move one brake shoe toward the other brake shoe. The locking assembly is responsive to car speed and/or movement of the car from a floor with its doors open. Switches operable by the cam follower control the car electrical controls so that movement of the car is prevented when the springs are not compressed and when there is excessive shoe wear.</p> |
