Pilot pump bleed control for earthmoving scrapers
US3935792A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 26, 1974 |
| Grant date | Feb 3, 1976 |
| Priority date | — |
| Expiry date | Jun 26, 1994 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B20/004
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
In an earthmoving scraper a low volume, low pressure, pilot pump supplies fluid pressure to a pilot control valve which routes this fluid through bleed lines to a remote scraper control valve that operates the bowl jacks on the scraper from a separate source of pressurized hydraulic fluid. By manually varying the bleed rates of the output of the pilot pump with the spool of the pilot valve, proportion actuation of the control valve can be obtained through differential pressures in the bleed lines connecting it to the pilot valve. A safety valve connected in the bowl carry circuit supplies an alternate source of fluid pressure to the pilot valve if the pilot pump fails, ensuring positive fail-safe operation of the system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.