An electric power tool includes: a brushless motor having a plurality of stator windings and configured to rotate in accordance with voltages applied to the plurality of stator windings, an induced voltage being generated in accordance with a rotation of the brushless motor; a rectifier circuit configured to rectify an AC voltage; a smoothing capacitor configured to smooth the AC voltage rectified by the rectifier circuit to a pulsation voltage having a maximum value larger than the induced voltage and a minimum value smaller than the induced voltage; and an inverter circuit configured to perform switching operations to output the pulsation voltage to the plurality of stator windings by rotation.

Electric power tool

A power tool includes an output shaft configured to rotate about a longitudinal axis, a motor drivably connected to the output shaft to impart rotary motions thereto, and a rotational motion sensor spatially separated from the output shaft and operable to determine the user-imparted rotational motion of the power tool with respect to the longitudinal axis. A controller is electrically connected to the rotational motion sensor and the motor. The controller determines angular velocity of the power tool about the axis, rotational displacement of the power tool about the axis, and/or a direction of the rotational displacement using input from the rotational motion sensor. The controller then controls the motor according to the angular velocity, the rotational displacement, and/or the direction of the rotational displacement.

Power screwdriver having rotary input control

A power tool includes a housing, a motor, an output member driven by the motor, and a reaming attachment coupled to the output member. The reaming attachment has a front end portion selectively driven in rotation by the output member to drive a fastener into a workpiece, and a reaming portion selectively driven in rotation by the output member to remove material from an end surface of a conduit. A rotational motion sensor in the housing is operable to detect rotational motion of the housing about an axis. A controller receives a signal indicative of rotational motion from the sensor, determines a direction of the rotational motion of the housing, and drives the motor in a direction corresponding to the direction of rotational motion of the housing.

Power tool having rotary input control

An apparatus is provided for diagnosing the state of health of a vehicle and for providing the operator of the vehicle with a substantially real-time indication of the efficiency of the vehicle in performing an assigned task with respect to a predetermined goal. A processor on-board the vehicle monitors sensors that provide information regarding the state of health of the vehicle and the amount of work the vehicle has done. In response to anomalies in the data from the sensors, the processor records information that describes events leading up to the occurrence of the anomaly for later analysis that can be used to diagnose the cause of the anomaly. The sensors are also used to prompt the operator of the vehicle to operate the vehicle at optimum efficiency.

Apparatus for Tracking and Recording Vital Signs and Task-Related Information of a Vehicle to Identify Operating Patterns

A control system is provided for use in a power tool The control system includes: a rotational rate sensor having a resonating mass and a controller electrically connected to the rotational rate sensor The rotational rate sensor detects lateral displacement of the resonating mass and generates a signal indicative of the detected lateral displacement, such that the lateral displacement is directly proportional to a rotational speed at which the power tool rotates about an axis of the rotary shaft Based on the generated signal, the controller initiates a protective operation to avoid further undesirable rotation of the power tool The controller may opt to reduce the torque applied to shaft to a non-zero value that enables the operator to regain control of the tool

Power tool anti-kickback system with rotational rate sensor

A microprocessor based motor controller which provides open loop speed control at low conduction angles, closed loop speed control at high conduction angles, and a smooth transition between open loop and closed loop zones. In open loop, the motor speed is selected and is permitted to vary with applied load. In closed loop, the motor speed is held constant, substantially irrespective of load. In the transition zone, the motor is operated in a hybrid open loop, closed loop fashion. Anti-kickback protection is also provided based on a percentage change in the motor's rotational period.

Robert Bradus

Papers

Microprocessor based motor control