Patent ID: 7712584

Claim:
A traction sheave elevator without counterweight, comprising: an elevator car suspended by a hoisting rope; a traction sheave operatively connected to the elevator car by the hoistingrope; and a brake structure configured to engage with the traction sheave in a braking operation in an upward motion and a downward motion of the elevator car; wherein the brake structure includes: a first brake element; and a second brake element; wherein the first brake element includes: a surface engageable with the traction sheave; a first contact surface; and a first sliding surface; wherein the second brake element includes: a second contact surface opposite to the first contact surface; and a second sliding surface opposite to the first sliding surface; wherein, during a braking operation, when the elevator car moves with the upward motion, the first sliding surface slides along the second sliding surface relative to the second brake element and a distance between the first and second contact surfaces increases, so as to provide a braking force that is less than a full braking force, and wherein, during a braking operation, when the elevator car moves with the downward motion, the second contact surface contacts the first contact surface in order to prevent the first sliding surface from sliding along the second sliding surface relative to the second brake element, so as to provide the full braking force.