Title:
HYDRAULIC HAMMERING DEVICE
Document Type and Number:
WIPO Patent Application WO/2017/010400
Kind Code:
A1
Abstract:
The present invention increases a hammer output by setting a piston stroke to a short stroke while maintaining hammering energy. This hydraulic hammering device is provided with: a cylinder (100); a piston (200) slidingly fitted in the cylinder (100); a piston front chamber (110) and a piston rear chamber (111) defined between the outer circumferential surface of the piston (200) and the inner circumferential surface of the cylinder (100), and arranged, separately from each other, at the front and rear sides in the axis direction; a switching valve mechanism (130) that switches at least one of the piston front chamber (110) and the piston rear chamber (111) to at least one of a high pressure circuit (101) and a low pressure circuit (102), to drive the piston (200); and a speed increasing piston (410) that is provided behind the piston (200) and that serves as an urging means to urge the piston (200) forward by making contact with the piston (200) at a timing at which a braking force acts on the piston (200) in a retracting step of the piston (200).
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| JPH07214479 | HYDRAULIC IMPACT TOOL |
| WO/2013/143520 | VALVE |
Inventors:
KOIZUMI MASAHIRO (JP)
Application Number:
PCT/JP2016/070155
Publication Date:
January 19, 2017
Filing Date:
July 07, 2016
Export Citation:
Assignee:
FURUKAWA ROCK DRILL CO LTD (JP)
International Classes:
B25D9/26; E21B1/26
Foreign References:
| JPS6175982U | 1986-05-22 | |||
| JPS4713595B | ||||
| JPS5689478U | 1981-07-17 | |||
| JPH0493185A | 1992-03-25 | |||
| JPS6313672U | 1988-01-29 | |||
| JP2000176859A | 2000-06-27 | |||
| JPS59156677A | 1984-09-05 |
Other References:
See also references of EP 3323564A4
Attorney, Agent or Firm:
MORI Tetsuya et al. (JP)
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