Variable Volume Accumulator

A hammer assembly comprising:

• a hammer housing;
• a work tool movably supported in the hammer housing;
• a gas chamber defined in the hammer housing and containing a compressible gas;
• an accumulator assembly including an interior space, a barrier dividing the interior space into a first interior portion containing a compressible gas and a second interior portion configured to receive a pressurized fluid, the barrier being configured to be movable in response to changing the amount of pressurized fluid in the second interior portion and such that movement of the barrier varies the volume of the first interior portion, the first interior portion being in communication with the gas chamber;
• and
• a piston movably disposed in the housing, the piston being movable in a first direction away from the work tool to thereby compress the compressible gas in the gas chamber and in the first interior portion of the accumulator assembly producing a biasing force on the piston acting in a second direction towards the work tool, the piston being movable in the second direction, at least in part, in response to the biasing force.

An accumulator assembly comprising:

• a housing defining an interior space;
• a barrier supported on the housing and dividing the interior space into a first portion interior portion containing a compressible gas and a second interior portion configured to be in communication with a pressurized fluid;
• the barrier being configured to be movable in response to changing the amount of pressurized fluid in the second interior portion of the interior space such that movement of the barrier varies the volume of the first interior portion;
• and
• the first interior portion being in communication with a fluid system such that an increase in pressure of the fluid system compresses the compressible gas in the first interior portion increasing the pressure thereof.