US 12,304,034 B2
Impact tool with collapsible member to compensate for thermal expansion
Mitchell Carlson, Lisbon, WI (US); Ding Feng Hu, Dongguan (CN); Zhiqiang Yu, Dongguan (CN); and Fanbin Zeng, Dongguan (CN)
Assigned to MILWAUKEE ELECTRIC TOOL CORPORATION, Brookfield, WI (US)
Filed by MILWAUKEE ELECTRIC TOOL CORPORATION, Brookfield, WI (US)
Filed on Feb. 12, 2024, as Appl. No. 18/439,466.
Application 18/439,466 is a continuation of application No. 17/408,898, filed on Aug. 23, 2021, granted, now 11,897,095.
Application 17/408,898 is a continuation of application No. 16/309,625, granted, now 11,097,403, issued on Aug. 24, 2021, previously published as PCT/US2017/048626, filed on Aug. 25, 2017.
Claims priority of provisional application 62/379,393, filed on Aug. 25, 2016.
Prior Publication US 2024/0181609 A1, Jun. 6, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. B25B 21/02 (2006.01); B25F 5/02 (2006.01)
CPC B25B 21/026 (2013.01) [B25F 5/02 (2013.01)] 20 Claims
OG exemplary drawing
 
1. 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 and a second end opposite the first end, the collapsible member being maintained in a shape coinciding with that of the cavity by fitment within the cavity, 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.