Hydraulic drive circuit for load-handling machines
US4317466A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 1, 1980 |
| Grant date | Mar 2, 1982 |
| Priority date | — |
| Expiry date | Apr 1, 2000 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/87177
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A hydraulic drive circuit for a load-handling machine such as hydraulic crawler crane, shovel or the like in which the maximum output pressure of the circuit is determined by a main relief valve provided on the delivery side of a hydraulic pump. The drive circuit is capable of producing a surge of power or output by automatically increasing the relief pressure of the main relief valve above a rated pressure of the circuit for a short time period of about a few seconds, when required for extracting an implanted pile, for pulling a bucket which is caught on a large stone, or for getting a machine out of a muddy spot. At the end of the predetermined time period, the circuit pressure is automatically returned to the level of the rated pressure. The surge output is from 130% to 150% of the rated output but allows use of hydraulic components or an engine of a capacity designed for the rated output without troubles or engine stops.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.