Fluid control system
US4089388A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 7, 1976 |
| Grant date | May 16, 1978 |
| Priority date | — |
| Expiry date | Sep 7, 1996 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB66F11/044
- WIPO fieldHandling
- WIPO sectorMechanical engineering
Abstract
A hydraulic valve system uses spool type pilot valves with the valve openings notched to provide non-linear response to movement of pilot valves. A servo type valve with a four-way spring centered spool is operated either manually or hydraulically by the spool pilot valve. A limit stop is located at each end of the servo spool valve. The notching geometry in the spools of both the pilot valve and servo valve provide a non-linear response such that controllability and safety are improved, without hysteresis. The system has a manual override on both ends of the servo valve which is operated independently of the pilot spool valve. The system is proposed for use on articulated aerial towers which consist of a mobile platform, a rotatable mounting for a lower boom, an upper boom having an articulated mounting on the lower boom, and personnel or tool carrying basket at the outer end of the upper boom.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.