Title:
HYDRAULIC CIRCUIT FOR CONCRETE PUMP
Document Type and Number:
Japanese Patent JP3718821
Kind Code:
B2
Abstract:
PURPOSE: To reduce the number of logic valves through which pressure oil passes during normal operation so as to suppress heating and thereby to eliminate the necessity of heightening the cooling capacity of an oil cooler, and enable single lung operation by only one main hydraulic cylinder.
CONSTITUTION: Pressure oil feed lines 19a, 19b and 19c, 19d and pressure oil discharge lines 20a, 20b and 20c, 20d are connected to the head side pressure chambers and rod side pressure chambers of main hydraulic cylinders 1, 2. By-pass lines 22, 23 are provided between the rod side pressure chambers and between the head side pressure chambers of the main hydraulic cylinders 1, 2. Logic valves 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 are built in the intermediate parts of the respective lines, and the respective logic valves 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 are opened/closed according to an operation mode.
Inventors:
Takayuki Yasuma
Application Number:
JP4659995A
Publication Date:
November 24, 2005
Filing Date:
February 13, 1995
Export Citation:
Assignee:
Ishikawajima Construction Machinery Co., Ltd.
International Classes:
F04B49/00; F04B15/02; F15B11/22; (IPC1-7): F04B15/02; F15B11/22
Domestic Patent References:
| JP5049824B2 | ||||
| JP62147054A | ||||
| JP57102579A |
Attorney, Agent or Firm:
Mitsuo Sakamoto