Hydraulically actuated forging hammer - uses force due to gas compressed by free piston to return main piston

摘要

A hydraulically operated forging hammer is connected to a piston (3) by the piston rod (2). The piston operates with an annular clearance (6) inside a cylinder (1) which houses a free piston (5). The free piston is fitted below the main piston. Gas in the lower space (7) is compressed by the free piston as it is forced downwards by hydraulic fluid admitted into the annular space (6). When hydraulic fluid is admitted into the space (8) it pushes the main piston downwards for the working stroke. After completion of the working stroke the gas pressure in the lower space (7) returns both pistons to their initial positions.