Method and device for damping the movement of a hammer piston
AssigneeAtlas Copco Aktiebolag
InventorKurt Osten Brannstrom
Life of this patent
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Abstract
A method for damping the movement of the hammer piston of a hammer mechanism and for catching the hammer piston in a forward end position when the drill tool is situated outside the operating range of the hammer piston is disclosed. During the return stroke of the hammer piston gas is driven from one chamber to another chamber through a slot. When the hammer piston exceeds its normal range of operation gas is driven through the slot in the other direction and also through a channel in the machine housing so that a weaker damping is obtained than during the return stroke. A hammer mechanism to be operated according to the above method is also disclosed.
Claims8
A method for damping the movement of a hammer piston (3) incorporated in a hammer mechanism, the hammer mechanism including a driving piston (2) reciprocably movable in a machine housing (1), the method comprising:
- driving said hammer piston (3) towards a tool (5) by said driving piston (2) via a pressure-gas cushion formed in a working chamber (4) of said housing (1) between said driving piston (2) and said hammer piston (3), and
- pneumatically damping the movement of said hammer piston (3) during the main part of the return stroke of the hammer piston (3), and pneumatically damping the movement of the hammer piston (3) when it exceeds its normal working stroke and catching the hammer piston (3) essentially without recoil at its forward end position when the tool is situated outside the operating range of the hammer piston,
- the pneumatic damping during the return stroke being greater than that applied when the hammer piston (3) exceeds its normal working stroke.
A hammer mechanism comprising:
- a machine housing (1) having a working chamber (4) therein,
- a driving piston (2) reciprocably movable in the machine housing,
- a hammer piston (3) arranged to be driven towards a tool (5) by the driving piston (2) via a pressure-gas cushion formed in the working chamber (4),
- a first pneumatic means (22,10) for damping the movement of the hammer piston (3) during its return stroke, and
- a second pneumatic means (6,10,12) for damping the movement of the hammer piston (3) when it exceeds its normal working stroke and for catching the hammer piston (3) substantially without recoil at its forward end position,
- said first pneumatic means damping the movement of the hammer piston (3) more than said second pneumatic means.
Dependencies are inferred from the claim text.