Variable traction mechanism for rotary actuated overspeed safety device

US6296080A · kind A · utility

Assignee

• OTIS ELEVATOR COMPANY · US

Inventors

• James M. Draper · Hartland, US
• Richard E. Kulak · Bristol, US

Key dates

• Filing date: Jun 21, 2000
• Grant date: Oct 2, 2001
• Expiry date: Jun 21, 2020

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B66B5/18
• WIPO field: Handling
• WIPO sector: Mechanical engineering

Abstract

In an elevator safety braking device, a variable traction mechanism in a rotary actuator allows the drive wheels of the rotary actuator to operate at a reduced preload during normal elevator operation. When engaging, a higher preload is necessary. In the event of safety braking, the variable traction mechanism increases the preload on the drive wheel to ensure timely and proper safety engagement. The variable traction mechanism therefore allows the drive wheels to be subjected to a reduced preload during normal operation, thus relaxing the design criteria for the drive wheels while maintaining reliability.