A power tool includes an outer housing having a drive unit support portion and a handle portion, an inner housing positioned at least partially within the outer housing, and a drive unit positioned in the drive unit support portion, the drive unit including an output member. The power tool also includes a power screw mechanism with a nut fixed relative to the outer housing and a screw coupled for co-rotation with the output member and axially movable relative to the output member. The screw is in threaded engagement with the nut such that the screw moves axially in response to rotation of the screw relative to the nut. The power tool also includes a working assembly coupled to the inner housing for movement in response to axial movement of the screw.

Disclosed is an electronic scale ruler, having a scale ruler main body, a main control board, an input, a display screen, a light source, a vernier base, and a distance conversion assembly. The scale ruler main body has an outer edge side. The light source is mounted on the outer edge side of the scale ruler main body, having a plurality of light beads and being capable of displaying scale. The vernier base is removably mounted on the outer edge side of the scale ruler main body, being capable of moving along a length direction of the outer edge side of the scale ruler main body. The distance conversion assembly is configured to calculate a movement of the vernier base from an origin on the outer edge side of the scale ruler main body.

A motor system includes a motor, and a multi-turn absolute encoder that detects a rotation number and an absolute angular position of a rotation shaft of the motor. The multi-turn absolute encoder includes: an absolute angular position detection device that detects the absolute angular position within one rotation period of the rotation shaft; and a storage element that stores the rotation number of the motor. Even if the driving of the multi-turn absolute encoder is stopped while the motor is stopped, the multi-turn absolute encoder detects the multi-turn position of the rotation shaft after startup. Further, the motor has a brake mechanism including: a gear-type brake wheel that rotates integrally with the rotation shaft; an engagement member capable of engaging with the teeth of the gear-type brake wheel; and an actuator which causes the teeth and the engagement member to engage with each other during braking.

A rotation angle detecting device includes: a rotating part rotating integrally with the rotating shaft and including a detected portion; an A-phase detector detecting change of a physical quantity caused by rotation of the rotating part, inside a first detection field over the detected portion and outputting an A-phase signal; and a B-phase detector detecting change of the physical quantity caused by rotation of the rotating part, inside a second detection field located over the detected portion and outputting a B-phase signal that is out of phase with the A-phase signal. The second detection field is shorter than the first detection field with respect to the direction perpendicular to the rotating direction of the rotating part.

A power tool includes a motor having an output shaft, an extensible member driven by the motor, a working assembly movable in response to contact with a distal end of the extensible member, a first sensor configured to detect a home position of the extensible member, a second sensor configured to detect rotation of the motor output shaft, and a controller in electrical communication with the first and second sensors. The controller is configured to drive the motor output shaft in a first rotational direction a predetermined number of revolutions counted by the second sensor, thereby displacing the extensible member from the home position. The controller is also configured to drive the motor output shaft in an opposite, second rotational direction to thereby return the extensible member until the home position is detected by the first sensor.

A motor may include a motor main body having a turning shaft and a motor case; a magnet that turns together with the turning shaft; a magnetism sensing element that faces the magnet; a circuit board on which the magnetism sensing element is mounted, the circuit board having a signal ground that is connected to a ground terminal of the magnetism sensing element; a circuit board holder that covers the circuit board from a side of the magnet; and a first shield member that covers the circuit board from a side opposite to the magnet. The first shield member and the circuit board holder are each made of an electrically-conductive material, and electrically connected to the signal ground.

An absolute position readout apparatus includes an encoder device and a readout device. The readout device includes multiple first and second magnetic sensing components that correspond to an absolute track of the encoder device, and a third magnetic sensing component and a fourth magnetic sensing components that correspond to an incremental track of the encoder device. The third magnetic sensing component is configured to be spaced apart from the fourth magnetic sensing component by a specific distance, so as to prevent misreading of absolute position information from the first or second magnetic sensing components being at positions corresponding to boundaries between adjacent magnetized regions of the absolute track.

An encoder device including: a position detection unit for detecting position information of a moving part; a magnet having a plurality of polarities along a moving direction of the moving part; an electric signal generation unit for generating an electric signal, based on a magnetic characteristic of a magnetosensitive part, the electric signal generation unit having the magnetosensitive part whose magnetic characteristic is changed by a change in magnetic field associated with movement of the moving part and a first magnetic body for guiding magnetic flux lines of the magnet toward the magnetosensitive part; and a second magnetic body for guiding magnetic flux lines of a part having one polarity of the magnet toward a part having other polarity of the magnet, the second magnetic body being disposed between the magnet and the magnetosensitive part.

A magnetic position detection device includes two magnetic scales 1a, 1b on which N and S magnetic poles are disposed alternately, magnetism sensing element groups 2a, 2b for measuring variation in magnetic fields formed respectively by the magnetic scales 1a, 1b, and a position calculation device 3 for calculating absolute positions of magnetism sensing elements 21 on the magnetic scales 1a, 1b from output values output by the magnetism sensing elements 21, wherein a difference between the respective numbers of magnetic poles on the magnetic scales 1a, 1b is 2, and the magnetism sensing elements 21 are disposed such that arrangement intervals between the magnetism sensing elements 21 of the respective magnetism sensing element groups 2a, 2b each take a value obtained by dividing a length of one magnetic pole equally by the number of magnetism sensing elements 21.

A scale and related method for a length-measuring system for recording the absolute values of angles or distances. The scale includes a printed circuit board, at least one track for identifying length information or angle information and a coding for identifying the scale. The coding has at least one coding element comprising at least two electrodes and a conductive connection between the electrodes on an insulator substrate. The electrical connection is configured to be irreversibly destroyed when an electrical current is applied.