A wrench includes a head having a first end and a second end and a handle extending from the head. The head defines and at least partially surrounds an opening. The head further defines at least one recess continuous with the opening. A distance between the first end and the second end of the head is greater than a cross-sectional diameter of a pipe flange of a hammer union.

A nut runner device includes a main body including spindles, and support portions that support the spindles rotatably around a longitudinal axial line, a detachable unit that is detachably connected to a tip of the main body, and includes a wrench that is disposed coaxially with the spindles and is rotatable integrally with the spindles and an air passage that extends inside of the spindles and the detachable unit in a direction along the longitudinal axial line, and connects a discharge port provided in the spindle, and a suction port that opens to a tip surface of the detachable unit, wherein a tip portion of the wrench is disposed in the suction port, and air that is sucked from the suction port to the discharge port 20c via the air passage passes by the tip portion of the wrench and a fastening member fitted to a tip of the wrench.

A nut runner device includes a main body including spindles, and support portions that support the spindles rotatably around a longitudinal axial line, a detachable unit that is detachably connected to a tip of the main body, and includes a wrench that is disposed coaxially with the spindles and is rotatable integrally with the spindles and an air passage that extends inside of the spindles and the detachable unit in a direction along the longitudinal axial line, and connects a discharge port provided in the spindle, and a suction port that opens to a tip surface of the detachable unit, wherein a tip portion of the wrench is disposed in the suction port, and air that is sucked from the suction port to the discharge port 20c via the air passage passes by the tip portion of the wrench and a fastening member fitted to a tip of the wrench.

A tool includes an operative rod, a guiding rod, a conveying screw and two detaching elements. The guiding rod includes a middle section connected to the operative rod and two terminal sections extending from the middle section. The conveying screw includes two threaded sections. Threads of the threaded sections extend in opposite directions. Each of the detaching elements includes a fixing aperture and a screw hole. The fixing aperture receives a corresponding one of the terminal sections of the guiding rod. The screw hole receives a corresponding one of the threaded sections of the conveying screw. Thus, the detaching elements are moved toward each other when the conveying screw is rotated in a first direction and that the detaching elements are moved from each other when the conveying screw is rotated in a second direction.

The present disclosure relates to a method for use in installation of a mill liner, the method including (a) retaining a mounting bolt at least partially within a liner opening extending through the mill liner, (b) positioning the mill liner against a mill shell so that the retained mounting bolt is aligned with a mill shell opening extending through the mill shell, (c) selectively coupling an extraction tool to the mounting bolt, the coupling performed by an operator outside of the mill shell, (d) detaching the mounting bolt from the liner using the extraction tool; (e) pulling the mounting bolt through the mill shell opening so that at least a portion of the mounting bolt protrudes outside of the mill shell, and, (e) securing a fastener onto the mounting bolt to thereby attach the mill liner to the mill.

An impact tool of the present disclosure provides an impact mechanism having a hammer and an anvil, the hammer being rotatable about a first axis and to periodically impact the anvil to drive rotation of the anvil about the first axis. The electric motor includes a plurality of pole pairs of windings and a rotor that is rotatable with respect to consecutively energized pole pairs of windings. No encoder or sensor is electronically coupled to the electric motor to detect a position of at least one magnet attached to the rotor with respect to at least one pole pair when the rotor is in a stopped condition. When the rotor is in the stopped condition, the motor controller energizes the at least one pole pair to initiate rotation and detect a back EMF generated by movement of the rotor without a sensor or encoder to indicate the predetermined location of the at least one magnet attached to the rotor with respect to the at least one pole pair.

An impact tool of the present disclosure provides an impact mechanism having a hammer and an anvil, the hammer being rotatable about a first axis and to periodically impact the anvil to drive rotation of the anvil about the first axis. The electric motor includes a plurality of pole pairs of windings and a rotor that is rotatable with respect to consecutively energized pole pairs of windings. No encoder or sensor is electronically coupled to the electric motor to detect a position of at least one magnet attached to the rotor with respect to at least one pole pair when the rotor is in a stopped condition. When the rotor is in the stopped condition, the motor controller energizes the at least one pole pair to initiate rotation and detect a back EMF generated by movement of the rotor without a sensor or encoder to indicate the predetermined location of the at least one magnet attached to the rotor with respect to the at least one pole pair.

An electric power tool in one aspect of the present disclosure includes a motor, an impact mechanism, an impact detector, and a control circuit. The control circuit controls a motor current based on a drive duty ratio in a first driving term. The first driving term corresponds to a time period from when the motor is started until impact is detect. The drive duty ratio corresponds to a sum of a basic duty ratio and a proportional duty ratio. The control circuit controls the motor current so that an actual rotational speed of the motor is consistent with a target rotational speed after elapse of the first driving term.

An electric power tool in one aspect of the present disclosure includes a motor, an impact mechanism, an impact detector, and a control circuit. The control circuit controls a motor current based on a drive duty ratio in a first driving term. The first driving term corresponds to a time period from when the motor is started until impact is detect. The drive duty ratio corresponds to a sum of a basic duty ratio and a proportional duty ratio. The control circuit controls the motor current so that an actual rotational speed of the motor is consistent with a target rotational speed after elapse of the first driving term.

An impact driver includes a hammer that is rotated by a motor and an anvil configured to be struck by the hammer to rotate the anvil about a rotational axis. A hammer case houses the hammer. Two or more bearings are provided inside the hammer case and support the anvil. To inhibit vibration of the anvil during operation, the bearings may be differing types, such as a regular ball bearing and an angular contact ball bearing, and/or the bearings may have different inner and/or outer diameters. A contact member, such as an O-ring, may be disposed in an insertion hole of the anvil to reduce vibrations that are transmitted to the tool bit.