Black Decker Inc.

Joshua D West

Uday S Deshpande

Brandon L Verbrugge

Shailesh P Waikar

Daniel Puzio

Craig Alan Schell

Hung T Du

Bhanuprasad V Gorti

Qiang J Zhang

William F Hilsher

Uday Deshpande

Qiang Zhang

A permanent magnet, DC motor especially well adapted for use in power tools, and particularly hand-held, battery powered power tools. The motor includes two sets of armature coils, with each set of coils being coupled to separate sets of commutator bars on an armature. Separate pairs of brushes are used to interface with the two sets of commutator bars. A switching subsystem is controlled either manually by a user engageable switch or automatically by a controller, to connect the two sets of coils in either series or parallel configurations. The series configuration provides a greater efficiency, but with a lower power output than the parallel connection. The parallel connection provides a greater maximum power output from the motor. Thus, the operating characteristics of the tool can be tailored to better meet the needs of a work task, and in a manner than makes most efficient use of available battery power.

DC motor with dual commutator bar set and selectable series and parallel connected coils

A brush assembly may include a support member, a conductive arm having a first end portion and a second end portion, where the first end portion is coupled to the support member, a brush coupled to the second end portion of the conductive arm, and a biasing member configured to apply a force to the conductive arm.

Brush assembly including biasing member for applying force

A power tool having an electronically commutated DC motor capable of providing various operating modes ranging from a maximum efficiency operating mode to a maximum power operating mode. The motor has a rotor having permanent magnets mounted in recesses in a back iron of the rotor. In one embodiment the motor has three phase windings, each having at least a pair of coils. The phase windings are connected in either a delta or a wye configuration via electromechanical or electronic switching components, or a combination of both, by a controller within the tool. The coils in each phase winding can also be switched between series and parallel configurations to configure the motor to provide its various operating modes. In one embodiment a dual wound motor is disclosed that has its phase coils dynamically or statically switchable between series and parallel configurations.

Electronically commutated motor and control system

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 control scheme employed by the power tool may initiate different protective operations for different tool conditions.

Power tool anti-kickback system with rotational rate sensor

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Towson, MD, United States of America

Joshua D West