A handheld cut-off saw (300) for cutting concrete and stone, the handheld cut-off saw comprising a drive arrangement (100, 200, 600, 800) for driving a circular cutting tool (110), the drive arrangement comprising: a belt drive portion (120) comprising a first pulley (121) and a second pulley (122), wherein the first pulley is arranged to be powered by a power source (130) and to drive the second pulley via a belt (123), wherein the second pulley (122) has a larger pitch diameter than the first pulley (121); and a gear transmission portion (140) comprising a first gearwheel (141) and a second gearwheel (142), wherein the first gearwheel (141) is co-axially connected to the second pulley (122) and radially connected to the second gearwheel (142), and wherein the second gearwheel (142) is arranged to be co-axially connected to the circular cutting tool (110).

The present disclosure provides a spindle structure including a base, a spindle, a sliding member, a restoring mechanism, and a restriction member. The spindle is rotatably received in the base and forms a receiving room. An end of the receiving room is a blind end communicating exterior via a gas channel. The sliding member is slidably received in the receiving room, and two ends thereof are a piston and a driving portion respectively. A gas cavity is defined between the piston and the blind end. The sliding member tends to move toward the blind end due to the restoring mechanism. The restriction member is connected to the driving portion and radially deforms when the sliding member slides so as to fix or to release the tool-holder. The sliding member slides outward when the gas cavity is injected with gas via the gas channel.

A power turret device includes a turret set on which processing tools are disposed, a transmission gear set disposed in the turret set, an inner axle penetrating through the turret set, a clutch set disposed on the turret set and including first and second engagement units, and a driving set. The turret set includes a base and a turret portion having a head and a support shaft integrated with the head. The integration of the head and the support shaft facilitates the replacement of the turret portion and distributes the weight of the turret portion evenly to prevent undue wear. The turret portion rotates to move any selected processing tool to a proper processing position when the engagement units are separated. The engagement between the engagement units allows the selected processing tool to rotate on its axis. The processing accuracy is increased and the service life is prolonged.

A rotary shaft locking device includes a rotary shaft, a first angular contact ball bearing, a support, and an actuator. The rotary shaft is rotatable about a first axis and has a first contact surface. The first angular contact ball bearing includes an inner ring connected to the rotary shaft, an outer ring, and a plurality of balls disposed between the inner ring and the outer ring. The support has a second contact surface and rotatably supports the rotary shaft via the first angular contact ball bearing. The actuator is configured to move the rotary shaft and the inner ring with respect to the support and the outer ring in a first direction parallel to the first axis so that the first contact surface contacts the second contact surface to prohibit the rotary shaft from rotating and so that precompression that acts on the plurality of balls is reduced.

A rotary shaft locking device includes a rotary shaft, a first angular contact ball bearing, a support, and an actuator. The rotary shaft is rotatable about a first axis and has a first contact surface. The first angular contact ball bearing includes an inner ring connected to the rotary shaft, an outer ring, and a plurality of balls disposed between the inner ring and the outer ring. The support has a second contact surface and rotatably supports the rotary shaft via the first angular contact ball bearing. The actuator is configured to move the rotary shaft and the inner ring with respect to the support and the outer ring in a first direction parallel to the first axis so that the first contact surface contacts the second contact surface to prohibit the rotary shaft from rotating and so that precompression that acts on the plurality of balls is reduced.

A tool for driving a component with a knurling pattern around an outer surface of the component is provided. A shaft, with a first end, is in the form of at least a partial cylinder, where the at least partial cylinder has a first inner diameter that is less than an outer diameter of the knurling pattern. Serrations in the shaft have a pattern that matches the knurling pattern, which allow the serration in the shaft to engage with the knurling pattern so that when the shaft is rotated, the component is rotated.

A tool for driving a component with a knurling pattern around an outer surface of the component is provided. A shaft, with a first end, is in the form of at least a partial cylinder, where the at least partial cylinder has a first inner diameter that is less than an outer diameter of the knurling pattern. Serrations in the shaft have a pattern that matches the knurling pattern, which allow the serration in the shaft to engage with the knurling pattern so that when the shaft is rotated, the component is rotated.

An angle head holder is installed on a spindle having a positioning block mounted on its outer surface with a constraining groove. The angle head holder includes a body base, a driving shaft, a holder assembly, and a positioning device. The driving shaft and the holder assembly are disposed in the body base. The positioning device has a fixing ring and an adjusting assembly. The fixing ring is sleeved on the body base and has a receiving slot. The adjusting assembly has a connecting block, a positioning pin, and at least one lever pin. The connecting block is mounted to the fixing ring and has a receiving groove. The positioning pin protrudes out of the receiving groove, is limited by the constraining groove, and has a retaining groove. The at least one lever pin is mounted in the receiving slot and the retaining groove.

A power tool, in particular a router, includes a motor shaft, at least one output shaft defining an output axis that is coaxial with the output shaft, and at least one electromotive drive acting on the motor shaft. The motor shaft defines a motor axis with the electromotive drive which is coaxial with the motor shaft. The motor axis and the output axis are arranged substantially parallel to and at a distance from one another.

A mobile device for machining a workpiece, the mobile device including a shaft rotatable about a rotation axis; a carriage rotatable with the shaft about the rotation axis and axially, or radially displaceable relative to the rotation axis; a tool support for a cutting tool, the tool support connected to the carriage and displaceable along a carriage axis and in a direction perpendicular to the carriage axis; and a transmission that couples the shaft to the tool support and the carriage so that the tool support is displaceable along a path that includes an axial and a radial movement component relative to the shaft.