Clutch-brake steering valve mechanism for tractors
US4308893A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 9, 1979 |
| Grant date | Jan 5, 1982 |
| Priority date | — |
| Expiry date | Feb 9, 1999 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/87193
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
Clutch-brake steering unit having hydraulically actuated cylinders which are adapted for controlling same to control rotation of a track-drive sprocket in a crawler tractor, and which are under control of a clutch-brake steering valve mechanism. A bore in the valve is common to and receives both an independently slidable hydropotentiometer spool precisely providing a master setting pressure, and an independently slidable metering spool providing a single pressure signal always hydraulically matched with the precise master setting pressure. A clutch cylinder and a brake cylinder provided in the unit have an inlet-outlet port in common, and are so arranged on a spring-applied-brake, hydraulically-applied-clutch basis that the generated single pressure signal when applied to the inlet-outlet port alternately operates the cylinders to apply the brake and release the clutch, or to release the brake and apply the clutch, or by proper modulation to partially engage either, i.e., slip the clutch or drag the brake to intermediate degrees as desired.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.