Load compensator for spring counter-weighting mechanism
US5400721A · kind A · utility
Inventor
Key dates
| Filing date | Jun 3, 1993 |
| Grant date | Mar 28, 1995 |
| Priority date | — |
| Expiry date | Jun 3, 2013 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/18848
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
An improved load compensator for a spring counter-weighting mechanism including a snail cam to provide a constant counter-weight force is described. The cam provides a constant torque to a drum on which are wound cables for exerting a constant counter-weighting force. A manually operable device for altering the relative radial positions of the cam and drum varies the amount of the constant counter-weighting force. The cam is rotated with respect to the drum by a spur gear fitting within a ring gear fixed to the drum and rotated by a knob connected to an axle carrying a pinion gear engaging the spur gear. The spiral surface can be effectively reconfigured with respect to a portion of the cable fitting therearound.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.