Construction machine
US10858805B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 16, 2018 |
| Grant date | Dec 8, 2020 |
| Priority date | — |
| Expiry date | Jan 16, 2038 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF15B2211/7053
- WIPO fieldCivil engineering
- WIPO sectorOther fields
Abstract
A construction machine is provided which includes a hydraulic closed circuit in which a single rod hydraulic cylinder is driven directly by a bidirectionally tiltable variable displacement pump and can stably speed up the contraction action of the single rod hydraulic cylinder. In the case where a contraction action of a hydraulic cylinder 10 is instructed through an operation lever 30, when a differential pressure obtained by subtracting the pressure of a cap chamber 10a from the pressure of a rod chamber 10b is equal to or lower than a first threshold value a set to a level equal to or higher than a selection setting pressure of a flushing valve 14, a controller 20 closes a rod side selector valve 12b to disable rod assist action for supplying hydraulic fluid from a second hydraulic pump 8 to the rod chamber, and when the differential pressure is higher than the first threshold value, the controller 20 opens the rod side selector valve to enable the rod assist action.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.