Elevator sheave brake safety
AssigneeOtis Elevator Company
InventorsLouis Bialy, Anthony Cooney, William Sheridan, Edward Reiskin
Life of this patent
Estimating the term…
Abstract
The cable drive sheave (14) carries a wedge-shaped brake ring (44) engageable with V-shaped brake shoes (52, 58). Each shoe is spring biased (68, 76) tangentially toward the ring and resiliently supported and biased radially (50) toward the ring. The shoes are restrained (84) during normal elevator operation and released on either cab upward overspeed (22) or on cab movement from a landing with the doors open (32).
Claims31
In an elevator system having a cable supported car, a cable supported counterweight, a cable drive sheave, and a cable connecting said car and said counterweight and passing over said sheave, a safety braking system comprising:
- a brake ring on said sheave having a sheave braking surface comprising a pair of angularly disposed braking surfaces;
- a first brake shoe having a first brake shoe braking surface comprised of a pair of angularly disposed braking surfaces;
- one of said pair of angularly disposed braking surfaces being a V groove and the other being a wedge, each having substantially same included angle between the pair of braking surfaces;
- a support for supporting and guiding said first shoe in a direction with said first shoe bearing surface moving tangential to the sheave bearing surface;
- a first shoe load radial biasing means for resiliently biasing said shoe in said support substantially radially toward said brake ring;
- a first shoe engagement biasing means for urging said shoe tangentially into engagement with said brake ring;
- a first stop on said support for limiting travel of said first brake shoe at a location where said shoe braking surfaces and said sheave braking surfaces are in contact;
- first shoe disengaging means for holding said first brake shoe against said first shoe engagement biasing means out of engagement with said brake ring;
- a second brake shoe having a pair of second shoe braking surfaces complimentary to the pair of sheave braking surfaces;
- second shoe biasing means for urging said second shoe into contact with said brake ring;
- second shoe disablement means for holding said second shoe out of engagement with said brake ring;
- said sheave rotating in a direction away from said first shoe when said car is moving in the up direction;
- overspeed means for releasing said disengaging means on a detected overspeed in the upward direction;
- and
- locking means for releasing both said first shoe disengaging means and said second shoe disablement means on discrete movement of said car from a landing with the doors open.
Dependencies are inferred from the claim text.