Vacuum control system for lifting systems
US5035456A · kind A · utility
Inventor
Key dates
| Filing date | Mar 29, 1990 |
| Grant date | Jul 30, 1991 |
| Priority date | — |
| Expiry date | Mar 29, 2010 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB66F3/35
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
This invention provides improved body length adjustment value structure for a vacuum powered lifting system of the type that embodies a variable length lifting body responsive to the differential of pressure inside that body with atmospheric pressure to resolve critical manual control problems. Thus control is provided by proportional movement of a control member over a substantially linear range producing a smooth progressive movement of the lifting mechanism. This permits non-critical lowering and release of a work load object by unskilled operators. Thus, an air injection valve with an air release port, is positioned within the lifting body having an elongated slot operable over a control range proportionately change the body length by release of a progressively increasing flow of air into the body to increase air pressure and body length over the critical range of lowering and releasing the work load object in response to a corresponding substantially linear movement of the control member. Variable adjustment value structure establishes a known upper lift limit by control of the length of the body both under loaded and unloaded conditions, and provisions are made to keep a vacu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.