Title:
HYDRAULIC HAMMERING DEVICE
Document Type and Number:
WIPO Patent Application WO/2018/131689
Kind Code:
A1
Abstract:
The present invention increases a hammer output by setting piston stroke to short stroke while maintaining hammering energy without changing a hydraulic circuit arrangement. This hydraulic hammering device is provided with: a piston front chamber (110) and a piston rear chamber (111) which are defined between the outer circumferential surface of a piston (200) and the inner circumferential surface of a cylinder (100) and are so arranged as to be removed from each other in the axis direction to the front side and rear side, respectively; a switching valve mechanism (130) which switches the piston front chamber (110) and/or the piston rear chamber (111) to a high-pressure circuit (101) and/or a low-pressure circuit (102) and thus drives the piston; and a speed increasing piston (410) which is provided behind the piston and which abuts against the piston during backward stroke of the piston to urge the piston (200) forward. The timing at which the speed increasing piston (410) commences abutment against the piston is set so as to precede the timing at which the piston (200) is braked by the switching valve mechanism (130).
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Inventors:
KOIZUMI MASAHIRO (JP)
Application Number:
PCT/JP2018/000703
Publication Date:
July 19, 2018
Filing Date:
January 12, 2018
Export Citation:
Assignee:
FURUKAWA ROCK DRILL CO LTD (JP)
International Classes:
B25D9/12; B25D9/26; E21B1/00
Domestic Patent References:
| WO1998031509A1 | 1998-07-23 | |||
| WO2017010400A1 | 2017-01-19 |
Foreign References:
| JPS52100303A | 1977-08-23 | |||
| JPS6313672U | 1988-01-29 | |||
| JPH0362777U | 1991-06-19 | |||
| JPS578091A | 1982-01-16 | |||
| JPS4912785B1 | 1974-03-27 |
Other References:
See also references of EP 3569362A4
Attorney, Agent or Firm:
MORI Tetsuya et al. (JP)
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