Electronic clutch for power tool
First Claim
1. A method of controlling operation of a power tool having an electric motor drivably coupled to an output spindle, comprising:
- receiving, by a controller residing in the power tool, an input indicative of a clutch setting for an electronic clutch, the clutch setting being selectable from a plurality of driver modes and each of the plurality of driver modes specifies a different value of torque at which to interrupt transmission of torque to the output spindle;
setting, by the controller, the value of a maximum current threshold in accordance with the selected one of the plurality of driver modes;
determining, by the controller, rotational speed of the electric motor;
determining, by the controller, an amount of current being delivered to the electric motor;
comparing, by the controller, the amount of current being delivered to the electric motor to the maximum current threshold; and
interrupting transmission of torque to the output spindle when the amount of current being delivered to the electric motor exceeds the maximum current threshold and the rotational speed of the electric motor is decreasing.
1 Assignment
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Accused Products
Abstract
A method is presented for controlling operation of a power tool having an electric motor drivably coupled to an output spindle. The method includes: receiving an input indicative of a clutch setting for an electronic clutch, where the clutch setting is selectable from a plurality of driver modes; setting the value of a maximum current threshold in accordance with the selected one of the plurality of driver modes; determining rotational speed of the electric motor; determining an amount of current being delivered to the electric motor; comparing the amount of current being delivered to the electric motor to the maximum current threshold; and interrupting transmission of torque to the output spindle when the amount of current being delivered to the electric motor exceeds the maximum current threshold and the rotational speed of the electric motor is decreasing.
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Citations
20 Claims
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1. A method of controlling operation of a power tool having an electric motor drivably coupled to an output spindle, comprising:
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receiving, by a controller residing in the power tool, an input indicative of a clutch setting for an electronic clutch, the clutch setting being selectable from a plurality of driver modes and each of the plurality of driver modes specifies a different value of torque at which to interrupt transmission of torque to the output spindle; setting, by the controller, the value of a maximum current threshold in accordance with the selected one of the plurality of driver modes; determining, by the controller, rotational speed of the electric motor; determining, by the controller, an amount of current being delivered to the electric motor; comparing, by the controller, the amount of current being delivered to the electric motor to the maximum current threshold; and interrupting transmission of torque to the output spindle when the amount of current being delivered to the electric motor exceeds the maximum current threshold and the rotational speed of the electric motor is decreasing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of controlling operation of a power tool having an electric motor drivably coupled to an output spindle, comprising:
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receiving, by a controller residing in the power tool, an input indicative of a clutch setting for an electronic clutch, the clutch setting being selectable from a plurality of driver modes and each of the plurality of driver modes specifies a different value of torque at which to interrupt transmission of torque to the output spindle; determining, by the controller, an amount of current being delivered to the electric motor; determining, by the controller, rotational speed of the electric motor; and monitoring, by the controller, torque applied to the output spindle when the clutch setting is in a select one of the plurality of driver modes, wherein monitoring torque further includes comparing the amount of current being delivered to the electric motor to a first current threshold; determining whether the rotational speed of the electric motor is decreasing, the determination being performed when the amount of current being delivered to the electric motor exceeds the first current threshold; comparing the amount of current being delivered to the electric motor to a second current threshold, the comparison being performed when the amount of current being delivered to the electric motor exceeds the first current threshold and the rotational speed of the electric motor is decreasing, where the value of the second current threshold is larger than the first current threshold; and interrupting transmission of torque to the output spindle without the use of a mechanical clutch when the amount of current being delivered to the electric motor exceeds the second current threshold. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method of controlling operation of a power tool having an electric motor drivably coupled to an output spindle, comprising:
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determining, by a controller residing in the power tool, whether a switch has been activated to deliver power to the electric motor; determining, by the controller, rotational speed of the electric motor; determining, by the controller, an amount of current being delivered to the electric motor; comparing, by the controller, the amount of current being delivered to the electric motor to a maximum current threshold; interrupting transmission of torque to the output spindle when the amount of current being delivered to the electric motor exceeds the maximum current threshold and the rotational speed of the electric motor is decreasing; determining, by the controller, whether the switch has been activated within a predetermined time period after interrupting transmission of torque to the output spindle; and interrupting transmission of torque to the output spindle when the switch has been activated within a predetermined time period after interrupting transmission of torque to the output spindle and the amount of current being delivered to the electric motor exceeds a second current threshold value that is less than the maximum current threshold. - View Dependent Claims (17, 18, 19, 20)
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Specification