| 摘要 |
PROBLEM TO BE SOLVED: To achieve a low-bulk compact construction, cost reduction, and maintenability in a jack device to be used for a press machine requiring low thrust and a high speed or a low speed and high thrust by using a two-way discharge pump means, namely, a fluid source of a direct drive volume control (DDV) type without using a power unit consisting of a pump and a control valve. SOLUTION: The jack device comprises a double cylinder 2, a first valve means 3, a second valve means 4, a communication means 5, and a two-way discharge pump means 6. Particularly, the double cylinder 2 consists of two large and small cylinders A, B combined in an inner and outer double fashion. The first valve means 3, the second valve means 4, and the communication means 5 are provided to simplify the two-way discharge pump means 6. The first and second valve means 3, 4 are provided outside the double cylinder 2. COPYRIGHT: (C)2009,JPO&INPIT
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