Black Decker Inc.

Peter Hague Wadeson

Brian E Friedman

Wing Lin

Tyler Petrus

BhanuPrakash Villuri

Eric Louis Kunz

A rotary impact tool includes a motor and an impact mechanism. The impact mechanism includes a cam shaft with a first cam groove rotatably driven by the motor, a cam ring received over the cam shaft with a second cam groove on its inner surface and a third cam groove on its outer surface, a hammer received over the cam ring with a fourth cam groove on its inner surface, an anvil with an output shaft and configured to be selectively engaged by the hammer, a spring configured to bias the hammer toward the anvil, a first ball received in the first and second cam grooves to couple the cam ring to the cam shaft, and a second ball received in the third and fourth cam grooves to couple the hammer to the cam ring.

Impact power tool and impact mechanism

An impact power tool includes a housing, a motor, a controller, an impact mechanism configured to be driven by the motor, and an output spindle configured to receive rotational impacts from the impact mechanism to rotate the output spindle. The controller is configured to detect a first impact of the rotational impacts or to detect when the motor speed drops below a speed threshold value. The controller is configured to control the motor to have a first non-zero target rotational speed using closed loop control for a predetermined time period after the first impact is detected or when the motor speed dropping below the speed threshold value is detected. The controller is configured to control the motor to have a second non-zero target rotational speed using the closed loop control after the predetermined time period. The first non-zero target rotational speed is less than the second non-zero target rotational speed.

Impact tools and control modes

A power tool includes a housing, a brushless motor received in the housing, a power switch coupled to the housing and actuatable by a user, a controller configured to control power delivery to the motor in response to actuation of the power switch, and an output spindle configured to rotate when the motor is energized. The controller is configured to maintain an amount of current delivered to the motor to be less than or equal to a current limit by turning off or reducing power to the motor for a time period if the current exceeds the current limit and then restarting power delivery to the motor. The time period is greater than the duration of one full current cycle.

An impact power tool includes a housing, a motor, a controller, an output member configured to be rotated when the motor is energized, and an impact mechanism configured to rotationally drive the output member. The impact mechanism is configured to selectively apply rotational impacts to the output member when a torque on the output member exceeds a torque threshold. The controller is configured to control the motor during a first phase of operation with open loop control and a baseline conduction band and advance angle setting when a sensed tool operation parameter is one of above or below a threshold value. The controller is configured to control the motor during a second phase of operation with closed speed loop control and an increased conduction band and advance angle setting when the sensed tool operation parameter is the other of above or below the threshold value.

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Silver Spring, MD, United States of America

Peter Hague Wadeson