Safety mechanism for a rotary hammer
AssigneeBlack & Decker Inc.
InventorsDavid A. Carrier, Daniel Puzio, Robert Bradus
Life of this patent
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Abstract
An improved method is provided for controlling a power tool having a rotary shaft. The method includes: disposing an inertial mass in a housing of the power tool, such that the inertial mass is freely rotatable about an axis of rotation which is axially aligned with the rotary shaft; monitoring rotational motion of the power tool in relation to the inertial mass during operation of the power tool; and activating a protective operation based on the rotational motion of the power tool in relation to the inertial mass.
Claims12
A method for initiating a protective response in a power tool having a rotary shaft driven by a motor, comprising:
- arranging a sensing element in fixed relation to a housing of the tool to detect rotational motion of the housing about a longitudinal axis of the rotary shaft;
- monitoring rotational motion of the tool about the longitudinal axis of the rotary shaft using the sensing element;
- detecting speed of the motor;
- setting a displacement threshold that varies as a function of the detected motor speed;
- and
- activating a protective operation by a controller disposed in the tool when rotational displacement of the tool exceeds the displacement threshold.
A method for initiating a protective response in a power tool having a rotary shaft driven by a motor, comprising:
- disposing an inertial mass comprised of a solid cylindrical body in a housing of the power tool, the inertial mass being freely rotatable about an axis of rotation and the axis of rotation being axially aligned with the rotary shaft,
- monitoring rotational motion of the housing in relation to the inertial mass;
- detecting speed of the motor;
- setting a displacement threshold that varies as a function of the detected motor speed;
- and
- activating a protective operation by a controller disposed in the tool when rotational displacement of the tool exceeds the displacement threshold.
Dependencies are inferred from the claim text.