The disclosure relates to a brake device for an electric motor, which has at least one armature winding and at least one field winding, comprising at least one open-loop and/or closed-loop control unit at least for open-loop control and/or closed-loop control of at least one electric current through the armature winding and/or through the field winding. According to the disclosure, in the event of short-circuit braking of the electric motor, the open-loop and/or control-loop unit is intended to reduce, at least temporarily, an electric armature current flowing through the armature winding.

Twisting of a locking member due to cogging torque is reduced without lowering the locking and unlocking operability for a user. A power tool includes a housing, an electric motor located inside the housing and including a permanent magnet, a shaft rotatable about an axis relative to the housing to transmit power from the electric motor, a locking member movable between a lock position and an unlock position in a nonenergized state of the electric motor and engageable with the shaft at the lock position to lock rotation of the shaft, and an abutting member that applies, to the locking member at the lock position, a force in a direction opposite to an axial torque caused by the permanent magnet and applied to the locking member.

A force and moment canceling reciprocating mechanism for a power-driven tool may include a transmission including an input gear assembly and an output gear assembly, coupled to a reciprocating mechanism. The input gear assembly may include a first input gear coaxially aligned with a second input gear. The output gear assembly may include a first output gear coaxially arranged with a second output gear. The reciprocating mechanism may be coupled to the output gear assembly, to convert rotational motion to linear motion, for output to an output accessory of the tool. One or both of the first and second input gears may include counterweights, or counterweight masses, and one or both of the first and second output gears may include counterweights, or counterweight masses. The counterweighting of the input and output gear assemblies may provide for the cancelation of forces and moments generated by the operation of the motor and the transmission, and the reciprocal motion of the reciprocating mechanism.

Disclosed is a cutting apparatus and method of cutting an insulative material. Said insulative material may be either flexible or rigid in nature. The insulative material is cut via a passive cutting wheel driven across a platen and engaged to a stationary drive belt about the passive cutting wheel axis. Engagement of the stationary drive belt with the passive cutting wheel axis results in a turning of the passive cutting wheel.

A reciprocating saw includes a housing, a motor positioned within the housing, and a shoe coupled to the housing. The shoe is configured to engage a workpiece. The reciprocating saw also includes a proximity sensor configured to detect the workpiece when engaged with the shoe. In response to the proximity sensor detecting formation of a gap between the shoe and the workpiece, the proximity sensor is operable to deactivate the motor.

The disclosure relates to a brake device for an electric motor, which has at least one armature winding and at least one field winding, comprising at least one open-loop and/or closed-loop control unit at least for open-loop control and/or closed-loop control of at least one electric current through the armature winding and/or through the field winding. According to the disclosure, in the event of short-circuit braking of the electric motor, the open-loop and/or control-loop unit is intended to reduce, at least temporarily, an electric armature current flowing through the armature winding.

A force and moment canceling reciprocating mechanism for a power-driven tool may include a transmission including an input gear assembly and an output gear assembly, coupled to a reciprocating mechanism. The input gear assembly may include a first input gear coaxially aligned with a second input gear. The output gear assembly may include a first output gear coaxially arranged with a second output gear. The reciprocating mechanism may be coupled to the output gear assembly, to convert rotational motion to linear motion, for output to an output accessory of the tool. One or both of the first and second input gears may include counterweights, or counterweight masses, and one or both of the first and second output gears may include counterweights, or counterweight masses. The counterweighting of the input and output gear assemblies may provide for the cancelation of forces and moments generated by the operation of the motor and the transmission, and the reciprocal motion of the reciprocating mechanism.

Twisting of a locking member due to cogging torque is reduced without lowering the locking and unlocking operability for a user. A power tool includes a housing, an electric motor located inside the housing and including a permanent magnet, a shaft rotatable about an axis relative to the housing to transmit power from the electric motor, a locking member movable between a lock position and an unlock position in a nonenergized state of the electric motor and engageable with the shaft at the lock position to lock rotation of the shaft, and an abutting member that applies, to the locking member at the lock position, a force in a direction opposite to an axial torque caused by the permanent magnet and applied to the locking member.

A jig saw including a clamping mechanism for removably clamping a saw blade and a driving mechanism. The clamping mechanism includes an actuating member and a clamping mechanism, the actuating member is configured to rotate about a first axis, thereby driving the clamping mechanism to achieve locking or unlocking of the saw blade. The actuating member includes an inclined surface extending in a rotation direction of the actuating member. The inclined surface cooperates with the clamping mechanism thereby to drive the clamping mechanism when the actuating member rotates. Since the clamping mechanism of the jig saw uses a clamping mechanism to apply pressure to the saw blade from the side, thereby abutting and fixing it on the main body, such a clamping mechanism therefore can be applied to different types of saw blades, regardless of the shape of the end faces of their clamping ends (e.g., V-shaped or U-shaped).

The present invention relates to a power tool and a method for controlling a stopping position of a cutting element in the power tool, the power tool including a cutting element, a sensor arranged to detect a position of the cutting element, and a controller operably connected with the sensor and the drive mechanism, for controlling a stopping position of the cutting element based on the detection by the sensor. When changing the cutting element, it is desirable to stop the cutting element at a higher position away from the object being cut, ideally the highest position. By utilizing a sensor to detect a sensed object in the cutting element, this method of control is automatic and reliable, allowing the user to change the cutting element easily and efficiently.