Provided is a power tool capable of performing braking in which deterioration and breakage of elements are inhibited. In a brake control, an arithmetic unit 21: performs a switching control of a combination of any of upper arm side Q1-Q3 switching elements and any of lower arm side switching elements Q4-Q6 while sequentially switching the elements; and causes a current to flow in a closed loop (a closed loop in the same direction as during driving of the power tool) in order through any of the upper arm side Q1-Q3 switching elements, stator coils 6e, any of the lower arm side switching elements Q4-Q6, and a first diode bridge 15.

Provided is a rotary tool. In the rotary tool, the rotating tip tool is mounted on a spindle by the fixture, and the spindle and the tip tool are rotated by a motor. The rotary tool has a switch which can switch the motor between a rotation state and a stop state, and a control device which controls the rotation of the motor corresponding to the operation of the switch. When the switch is turned off after a required time T elapses after the motor is started, the control device stops the rotary tool (104d, 106d) by performing a common braking operation on the spindle, and when the switch is turned off before the required time T elapses after the motor is started, the control device stops the tip tool (101d) by inertia without applying a braking force.

Provided is a rotary tool. In the rotary tool, the rotating tip tool is mounted on a spindle by the fixture, and the spindle and the tip tool are rotated by a motor. The rotary tool has a switch which can switch the motor between a rotation state and a stop state, and a control device which controls the rotation of the motor corresponding to the operation of the switch. When the switch is turned off after a required time T elapses after the motor is started, the control device stops the rotary tool (104d, 106d) by performing a common braking operation on the spindle, and when the switch is turned off before the required time T elapses after the motor is started, the control device stops the tip tool (101d) by inertia without applying a braking force.

A ground leveling grinder comprises a main motor connecting disk (1), wherein a driving shaft (4) is vertically provided in the middle section of the circular channel (41) of the main motor connecting disk (1), a hollow shaft sleeve (9) which is rotatable with respect to the driving shaft is sleeved outside the driving shaft (4), a worm gear (3) is installed at the periphery of the middle section of the hollow shaft sleeve (9), a worm (2) is installed in the worm box (10), the worm gear (3) is meshed with the worm (2), a driving gear (13) is installed at the lower end of the driving shaft (4), the driving gear (13) is meshed with an intermediate gear (14), the intermediate gear (14) is meshed with a driven gear (15), and a grinding disk (12) is installed on the output shaft of the driven gear (15).

A ground leveling grinder comprises a main motor connecting disk (1), wherein a driving shaft (4) is vertically provided in the middle section of the circular channel (41) of the main motor connecting disk (1), a hollow shaft sleeve (9) which is rotatable with respect to the driving shaft is sleeved outside the driving shaft (4), a worm gear (3) is installed at the periphery of the middle section of the hollow shaft sleeve (9), a worm (2) is installed in the worm box (10), the worm gear (3) is meshed with the worm (2), a driving gear (13) is installed at the lower end of the driving shaft (4), the driving gear (13) is meshed with an intermediate gear (14), the intermediate gear (14) is meshed with a driven gear (15), and a grinding disk (12) is installed on the output shaft of the driven gear (15).

An automatic adjustable stroke device for a random orbital machine has a housing with a central axis and a wall defining a cavity. A counterbalance shaft assembly is rotatably disposed at least partially within the cavity. A shaft portion of the counterweight shaft assemblies aligned with the central axis. A mounting assembly is disposed at least partially within the cavity. The mounting assembly has a workpiece attachment mechanism. A stroke adjuster couples the counterweight shaft with the mounting assembly. The stroke adjuster enables the mounting assembly to adjust its stroke upon rotation of counterweight shaft. The mounting assembly variably adjusts a stroke radius of the workpiece attachment mechanism with respect to the central axis of the housing. The stroke adjuster has a gear automatically adjusting the mounting assembly stroke.

An automatic adjustable stroke device for a random orbital machine has a housing with a central axis and a wall defining a cavity. A counterbalance shaft assembly is rotatably disposed at least partially within the cavity. A shaft portion of the counterweight shaft assemblies aligned with the central axis. A mounting assembly is disposed at least partially within the cavity. The mounting assembly has a workpiece attachment mechanism. A stroke adjuster couples the counterweight shaft with the mounting assembly. The stroke adjuster enables the mounting assembly to adjust its stroke upon rotation of counterweight shaft. The mounting assembly variably adjusts a stroke radius of the workpiece attachment mechanism with respect to the central axis of the housing. The stroke adjuster has a gear automatically adjusting the mounting assembly stroke.

To change the direction of water flowing toward a painted surface so as to flow toward the center side of a hood, a water deflecting member is provided that extends toward the center side of the hood while extending toward the painted surface as seen in a state where automatic wet sanding is performed. Thus, water bouncing off the painted surface is less likely to scatter over a wide area of the painted surface, and sanding dust is also less likely to scatter over a wide area of the painted surface. As a result, it is possible to eliminate the need for the troublesome task of wiping off sanding dust remaining on the painted surface, and to achieve a quality finish on the painted surface.

Disclosed are a method and equipment for reinforcing a concrete-filled steel tubular column with an outer concrete-filled steel tube. The method includes following steps: step 1, grinding and derusting an outer wall of a concrete-filled steel tubular column to be reinforced by an auxiliary device; step 2, welding two prefabricated semi-rectangular steel plates in advance, forming a complete rectangular steel tube with the two semi-rectangular steel plates and sleeving the rectangular steel tube outside the concrete-filled steel tubular column to be reinforced; and step 3, filling self-compacting concrete between the outer wall of the concrete-filled steel tubular column to be reinforced and an inner wall of the rectangular steel tube to complete a reinforcement.

Disclosed are a method and equipment for reinforcing a concrete-filled steel tubular column with an outer concrete-filled steel tube. The method includes following steps: step 1, grinding and derusting an outer wall of a concrete-filled steel tubular column to be reinforced by an auxiliary device; step 2, welding two prefabricated semi-rectangular steel plates in advance, forming a complete rectangular steel tube with the two semi-rectangular steel plates and sleeving the rectangular steel tube outside the concrete-filled steel tubular column to be reinforced; and step 3, filling self-compacting concrete between the outer wall of the concrete-filled steel tubular column to be reinforced and an inner wall of the rectangular steel tube to complete a reinforcement.