Power tool anti-kickback system with rotational rate sensor
First Claim
1. A control system suitable for use in a power tool having a motor drivably coupled to a rotary shaft to impart rotary motions thereto, comprising:
- a rotational rate sensor having a resonating mass, wherein the rotational rate sensor is operable to detect lateral displacement of the resonating mass and generate 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; and
a controller electrically connected to the rotational rate sensor and operable to initiate a protective operation based on the signal.
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Accused Products
Abstract
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.
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Citations
19 Claims
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1. A control system suitable for use in a power tool having a motor drivably coupled to a rotary shaft to impart rotary motions thereto, comprising:
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a rotational rate sensor having a resonating mass, wherein the rotational rate sensor is operable to detect lateral displacement of the resonating mass and generate 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; and
a controller electrically connected to the rotational rate sensor and operable to initiate a protective operation based on the signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A control scheme for a power tool having a rotary shaft, comprising:
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monitoring rotational motion of the power tool about a longitudinal axis of the rotary shaft;
determining a condition of the tool based on said rotational motion of the power tool;
initiating a first protective operation upon detecting a first tool condition; and
initiating a second protective operation upon detecting a second tool condition, where the first protective operation is different than the second protective operation. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A control scheme for a power tool having a rotary shaft, comprising:
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determining rotational motion of the power tool about a longitudinal axis of the rotary shaft;
determining rotational energy of experienced by the power tool based on the rotational motion; and
initiating a protective operation in relation to the power tool when the rotational energy exceeds a threshold. - View Dependent Claims (16, 17, 18, 19)
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Specification