Transmission engagement override valve
US5261456A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 1992 |
| Grant date | Nov 16, 1993 |
| Priority date | — |
| Expiry date | Nov 2, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/86622
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A transmission control system includes a plurality of hydraulic pressure operated control elements for engaging a gear of the transmission in response to actuation of a shift control lever having neutral and non-neutral positions, a plurality of control valves for controlling pressurization of the control elements and a pump for supplying pressurized fluid to the control valves. An engagement override system includes a switch which is coupled to the shift lever and which energizes a solenoid when the shift lever is in its neutral position and de-energizes the solenoid when the shift lever is in its non-neutral position. In a preferred embodiment, an engagement override valve includes a pilot operated valve which controls communication between the pump, a reservoir and the pressure operated control elements. The solenoid controls the pilot operated valve. The valve also includes a pilot chamber which is pressurized to move the valve to and hold the valve in a position wherein the pump is communicated with the pressure operated control elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.