Patent ID: 6966408

Claim:
A traction drive elevator having an autobalancing roping and drive arrangement comprising: a vertically displaceable elevator cab; a vertically displaceable counterweight; a suspension sheave section located above the cab and counterweight; a suspension rope passing over and guided by the suspension sheave section, the suspension rope having a first end attached to the counterweight on one side of the suspension sheave section and having a second end attached to the cab on the opposite side of the suspension sheave section; a drive sheave located below the cab and the counterweight; a drive rope passing under and in traction contact with the drive sheave, the drive rope having a first end attached to the counterweight and having a second end attached to the cab, the length of drive rope between the drive sheave and counterweight defining a force section, the traction contact between the drive sheave and the drive rope for driving the drive rope and vertically displacing the cab and counterweight; a weighting device connected to the drive sheave and imparting a force on the drive sheave and creating a tension in the force section that includes a downward vertical component of force; wherein said weighting device comprises a lever arm which is moved downward by a variable force, the variable force causing the weight of the cab and the weight of the counterweight to be equalized such that the amount of force necessary to move the car between landings is minimized, said variable force being generated by a weight which slides along the length of the lever arm; the downward vertical component of force in the force section and the weight of the counterweight combining to create a downward vertical force in the suspension rope on one side of the suspension sheave section to balance the downward force created by the weight of the cab on the opposite side of the sheave section.