Impact tool with collapsible member to compensate for thermal expansion

An impact power tool comprising:

• a motor;
• an output shaft to which a tool bit is attachable for performing work on a workpiece;
• and
• an impact mechanism disposed between the motor and the output shaft for converting a continuous torque output from the motor to discrete pulses of torque upon the output shaft, the impact mechanism including
• a cylinder assembly including a cylinder and an end cap attached for co-rotation with the cylinder,
• a first cavity at least partly defined by an interior surface of the cylinder and containing a hydraulic fluid,
• a blade extending from the output shaft to abut the interior surface of the cylinder,
• a second cavity in communication with the first cavity, and
• a collapsible member positioned within the second cavity, the collapsible member having a first end and a second end, with the first and second ends being disconnected from each other;
• wherein the collapsible member is collapsible to compensate for thermal expansion of the hydraulic fluid during operation of the impact mechanism.

An impact power tool comprising:

• a motor;
• an output shaft to which a tool bit is attachable for performing work on a workpiece;
• and
• an impact mechanism disposed between the motor and the output shaft for converting a continuous torque output from the motor to discrete pulses of torque upon the output shaft, the impact mechanism including
• a cylinder assembly,
• a cavity defined within the cylinder assembly containing a hydraulic fluid, and
• a collapsible member having a first end, a second end opposite the first end, and a gas trapped within an interior volume of the collapsible member defined between the first and second ends,
• wherein the collapsible member is bent into a curved shape, with the first and second ends being disconnected from each other;
• and
• wherein the collapsible member is collapsible to compensate for thermal expansion of the hydraulic fluid during operation of the impact mechanism.