Hydraulic drive system for construction machine
US11280059B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 24, 2017 |
| Grant date | Mar 22, 2022 |
| Priority date | — |
| Expiry date | Aug 10, 2039 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE02F9/2221
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A hydraulic drive system for a hydraulic excavator that enables leveling work and a jack-up operation by a blade in a float state, that can prevent a body from falling even when an operator has falsely operated the hydraulic excavator during the jack-up operation by the blade, and that yet can perform favorable leveling work with the blade turned into the float state is provided. A float switch 37, a float valve 38, and a controller 34 are provided, the float valve 38 is changed over to a float position VI upon operating the float switch 37 when the blade is not in a jack-up state, the float valve 38 is changed over from the float position VI to a normal position V when the float valve 38 is in a state of being at the float position VI and an operation lever device 22 has been operated, and the float valve 38 is kept at the normal position V when the float valve 38 is at the normal position V and the float switch 37 has been operated in the jack-up state.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.