Device for damping the recoil of a work tool connected to a percussion tool
AssigneeAtlas Copco Aktiebolag
InventorsAke T. Eklof, Per T. A. Fengsborn, Gunnar V. R. Romell
Life of this patent
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Abstract
A recoil damping device for a percussion tool in which the recoils are damped by means of a pressurized hydraulic fluid entrapped in the machine housing.
Claims14
A recoil damping device for a percussion tool which includes a work tool (22), a machine housing (10) coupled to said work tool and adapted to apply a feeding force forwardly to said work tool in a working direction, a hammer piston (17) reciprocating in the machine housing and adapted to deliver impact energy to said work tool, said work tool recoiling after application of impacts thereto, said recoil damping device damping the recoil of said work tool and comprising:
- a retard chamber (70) in said machine housing, said machine housing having a surface (73) defining the rearward portion of said retard chamber,
- a pressurized hydraulic fluid in said retard chamber,
- a retard piston (68) connected to said work tool said retard piston (68) being normally during operation a predetermined forward position which is remote from said surface (73) of said retard chamber (70),
- said retard piston (68) having a piston surface (69) which confines axially the retard chamber (70) towards the work tool, and
- means for maintaining hydraulic pressure in said retard chamber during operation to maintain said retard piston (68) and said work tool out of axial contact rearwardly with said surface (73) and said machine housing.
A device according to any of the preceding claims, wherein the fluid pressure in the retard chamber is of such magnitude that the force acting on the retard piston (68) in the working direction exceeds the feeding force.
A percussion tool comprising:
- a work tool,
- a machine housing (10) coupled to said work tool and adapted to apply a feeding force forwardly to said work tool in a working direction,
- a hammer piston (17) reciprocating in the machine housing and adapted to deliver impact energy to said work tool, said work tool recoiling after application of impacts thereto, and
- a recoil damping device damping the recoil of said work tool and comprising:
- a cushioning chamber (70) in said machine housing,
- said machine housing having a surface (73) defining the rearward portion of said cushioning chamber (70),
- a recoil pulse transmission member,
- said recoil pulse transmission member comprising a pressurized hydraulic fluid entrapped in said cushioning chamber,
- a retard piston (68) connected to said work tool, said retard piston being normally during operation in a predetermined forward position which is remote from said machine housing surface (73),
- said retard piston transmitting the recoils of the work tool to said recoil pulse transmission member,
- means for maintaining the pressure of said hydraulic fluid in said cushioning member at a level to prevent axial contact rearwardly of said retard piston with said machine housing surface (73), and
- spring means (48) constantly connected to said recoil pulse transmission member by means of a hydraulic fluid column,
- said spring means being adapted to equalize pressure shocks which arise in the recoil pulse transmission member when the recoils cause said retard piston to instantaneously move rearwards.
Dependencies are inferred from the claim text.