Document Type and Number:
Japanese Patent JPH0141475
Kind Code:
B2
Abstract:
In an hydraulic rock drill there is an hydraulic so called recoil damper that damps the reflected shock waves that propagates from the rock backwardly through the drill stem. The damper comprises a support piston (68) slidably in a cylinder so that a pressure chamber (20) is formed in which the support piston has a piston area. Narrow clearances (75,76) between the support (68) and its cylinder form leak passages and these leak passages are coupled in series with an orifice restrictor (84) to sump. The pressure peaks in the pressure chamber do not reach sealing rings located at the outer portions of the clearances.
Inventors:
AKE TORUSUTEN EKUREFU
Application Number:
JP1829282A
Publication Date:
September 05, 1989
Filing Date:
February 09, 1982
Export Citation:
Assignee:
ATLAS COPCO AB
International Classes:
B25D9/00; B23B45/16; B25D9/12; B25D9/14; B25D17/24; E21B1/26; E21B6/04
Next Patent: JPH0141476