Drift eliminator for series hydraulic lift system on tillage implements and the like
US4506898A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 2, 1984 |
| Grant date | Mar 26, 1985 |
| Priority date | — |
| Expiry date | Feb 2, 2004 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA01B63/22
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The double-acting hydraulic cylinders of the lift system are connected in a master-slave series relationship. When the cylinders have been retracted to a predetermined extent, a control valve between the last slave and a primary selector valve of the system is mechanically closed responsive to the arrival of the cylinders at such retracted condition and, simultaneously, the master is prevented from further retraction by either mechanical means or another hydraulic control valve between the master and the primary selector valve. Thus, the cylinders and their interconnecting lines are cut off from inadvertent overcharging, as well as fluid escape, so that all cylinders remain uniformly extended with drift from their established positions. Several circuit arrangements are disclosed, including provision for bleeding off higher than necessary operating pressures tending to become trapped within the cylinders and their associated flow lines after the cylinders have reached the intended point of retraction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.