| 摘要 |
A hydraulic impact mechanism comprises a housing (10) with a cylinder bore (11), a forward working chamber (23) and a rear working chamber (18), a hydraulic fluid supply passage (26) continuously connected to the forward working chamber (23) and a drain passage (33) connected to the rear working chamber (18), a hammer piston (12) reciprocally guided in the cylinder bore (11) for delivering hammer blows to a working implement (14) attached to the housing (10), a pressure accumulator (27) pre-loaded to a certain pressure level, and a distribution valve (30) for alternatingly connecting the rear working chamber (18) to the supply passage (26) and the drain passage (33) to thereby reciprocate the hammer piston (12), wherein a sequence valve (34) is provided in the drain passage (33) with the purpose to keep up the pressure in the rear working chamber (18) to such a level that the resulting forward directed force will prevent the piston (12) from being moved backwards in the cylinder bore (11) at pressure levels in the supply passage (26) below the pre-load pressure level of the accumulator (27). |
