Pump drive speed regulator with control-pressure-generating valve having spring biased by cam face on load directional control valve
US4862691A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 22, 1988 |
| Grant date | Sep 5, 1989 |
| Priority date | — |
| Expiry date | Apr 22, 2008 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/7128
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
Speed regulation of pump drive is set by a pressure-regulating valve providing a constant control pressure for a plurality of normal loads. If a high fluid consumption load such as the lifting cylinder of a forklift truck is to be simultaneously actuated the pump speed and net volumetric displacement must be increased. A higher speed-regulating control pressure from the pressure-regulating valve is required. The control valve for the high consumption load has a spool with an extending inclined cam contacting the biasing spring of the pressure-regulating valve. Upon actuation of this control valve the preload of the biasing spring is increased thereby adjusting the speed-regulating control pressure output of the pressure regulating valve. The pump engine or drive speed and the net volumetric displacement are increased.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.