Hydraulic swing control for boom assembly
US4718325A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 3, 1986 |
| Grant date | Jan 12, 1988 |
| Priority date | — |
| Expiry date | Nov 3, 2006 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE02F9/2207
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
An improved mechanism is provided for controlling the relative pivoting movement of two members about a main pivot axis as effected by two hydraulic motors. Each hydraulic motor is a double-acting piston-cylinder type that is fully extended when its respective line of action intersects the main pivot axis. Each hydraulic motor has an end port at each end. Two spaced-apart intermediate ports are provided within the piston stroke length of each motor. Pilot-actuated top dead center-selector valves are provided for reversing the flow to one of the hydraulic motors in response to a pressure differential between an end port and an intermediate port of the other of the hydraulic motors. Decelerator selector valves are provided to normally direct the return flow from the hydraulic motors so as to bypass a hydraulic cushioning circuit. The decelerator selector valves are pilot-actuated for directing the return flow to the cushioning circuit in response to a pressure differential between one of the end ports and one of the intermediate ports of either of the hydraulic motors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.