Hydraulic control system
US6253658A · kind A · utility
13Cited by
6References
5Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Nov 23, 1999 |
| Grant date | Jul 3, 2001 |
| Priority date | — |
| Expiry date | Nov 23, 2019 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/46
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
The invention provides a hydraulic control system capable of preventing an objective from crashing even if a load supporting passage is fractured or the like during a crane operation for moving down the objective with a hydraulic shovel. When a pilot pressure for switching a control valve 2 to a downward position b is less than a predetermined value, only first selector means switches, and when the pilot pressure exceeds the predetermined value, second selector means as well as the first selector means switches.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.