Capacitive, operator-sensing circuit for disabling engine of mobile power equipment
First Claim
1. A capacitive, operator-sensing circuit for sensing the presence of a hand of an operator on a gripping surface of a unit of power equipment having an internal combustion engine and shutting off the engine if the operator'"'"'s hand is removed from the gripping surface, the operator-sensing circuit comprising:
- a) a sensing electrode affixed to the gripping surface, a quantity of charge present on the sensing electrode having a first value if the operator'"'"'s hand overlies a portion of the sensing electrode and having a second value if the operator'"'"'s hand does not overlie the sensing electrode;
b) a charge-transfer sensor electrically coupled to the sensing electrode periodically transferring charge to the sensing electrode and sensing the quantity of charge on the sensing electrode, an output of the charge-transfer sensor generating a first output signal when the first value of the sensed charge on the sensing electrode is sensed and a second output signal, different from the first output signal, when the second value of the sensed charge on the sensing electrode is sensed; and
c) coupling circuity electrically coupling a magneto of the engine and the charge-transfer sensor for grounding the engine magneto and thereby shutting off the engine when the second output signal is generated by the charge-transfer sensor.
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Accused Products
Abstract
A capacitive, operator-sensing circuit for mobile power equipment includes a charge-transfer touch sensor that is electrically coupled to at least one sensing electrode mounted on a gripping surface of the mobile power equipment. The charge-transfer touch sensor is preferably a digital integrated circuit that operates to change an output voltage between two levels or states (logic high and logic low) depending upon a quantity of charge sensed on the at least one sensing electrode, the sensed charge on the at least one sensing electrode changing with the presence or absence of an operator'"'"'s hand on the at least one sensing electrode. The charge-transfer touch sensor outputs a DC voltage signal, maintaining a given output voltage level until the sensor senses a predetermined change in sensed charge on the sensing electrode. The capacitive operator-sensing circuit additionally includes coupling circuitry coupled between the charge-transfer touch sensor and a component of the equipment. A change in sensor output voltage from a first level to a second level causes a cessation of operation of the component. For example, the component may be an internal combustion engine of the equipment and a change in sensor output voltage from the first level to the second level causes the coupling circuitry to electrically couple a magneto of the engine to be coupled to ground thereby shutting off the engine.
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Citations
36 Claims
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1. A capacitive, operator-sensing circuit for sensing the presence of a hand of an operator on a gripping surface of a unit of power equipment having an internal combustion engine and shutting off the engine if the operator'"'"'s hand is removed from the gripping surface, the operator-sensing circuit comprising:
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a) a sensing electrode affixed to the gripping surface, a quantity of charge present on the sensing electrode having a first value if the operator'"'"'s hand overlies a portion of the sensing electrode and having a second value if the operator'"'"'s hand does not overlie the sensing electrode;
b) a charge-transfer sensor electrically coupled to the sensing electrode periodically transferring charge to the sensing electrode and sensing the quantity of charge on the sensing electrode, an output of the charge-transfer sensor generating a first output signal when the first value of the sensed charge on the sensing electrode is sensed and a second output signal, different from the first output signal, when the second value of the sensed charge on the sensing electrode is sensed; and
c) coupling circuity electrically coupling a magneto of the engine and the charge-transfer sensor for grounding the engine magneto and thereby shutting off the engine when the second output signal is generated by the charge-transfer sensor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A capacitive operator-sensing circuit in combination with a mobile power equipment unit, the combination comprising:
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a) the mobile power equipment including an internal combustion engine, an engine magneto, and a gripping surface for an operator to grip and control movement of the mobile power equipment unit; and
b) the capacitive operator-sensing circuit adapted to sense the presence of a hand of an operator on the gripping surface to shut off the engine if the operator'"'"'s hand is removed from the gripping surface, the capacitive operator-sensing circuit including;
1) a sensing electrode affixed to the gripping surface, a quantity of charge present on the sensing electrode having a first value if the operator'"'"'s hand overlies a portion of the sensing electrode and having a second value if the operator'"'"'s hand does not overlie the sensing electrode;
2) a charge-transfer sensor electrically coupled to the sensing electrode periodically transferring charge to the sensing electrode and sensing the quantity of charge on the sensing electrode, an output of the sensor generating a first output signal when the first value of sensed charge on the sensing electrode is sensed and a second output signal, different from the first output signal, when the second value of the sensed charge on the sensing electrode is sensed; and
3) coupling circuity electrically coupled between the engine magneto and the charge-transfer sensor for grounding the engine magneto and thereby shutting off the engine when the second output signal is received from the charge-transfer sensor. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of sensing the presence of a hand of an operator on a gripping surface of a mobile power equipment unit and causing cessation of operation of a component system of the equipment if the operator'"'"'s hand is removed from the gripping surface, the steps of the method comprising:
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a) providing a sensing electrode affixed to the mobile power equipment gripping surface wherein a quantity of charge on the sensing electrode has a first value if the operator'"'"'s hand overlies a portion of the sensing electrode and has a second value if the operator'"'"'s hand does not overlie the sensing electrode;
b) providing a charge-transfer sensor electrically coupled to the sensing electrode and periodically transferring charge to the sensing electrode, sensing the quantity of charge on the sensing electrode and generating a first output signal when the first value of sensed charge on the sensing electrode is sensed and a second output signal, different from the first output signal, when the second value of sensed charge of the sensing electrode is sensed; and
c) providing coupling circuitry electrically coupled between the charge-transfer sensor and the component, the coupling circuitry causing cessation of operation of the component system when the second output signal is generated by the charge-transfer sensor. - View Dependent Claims (21, 22, 23)
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24. A capacitive, operator-sensing circuit for sensing the presence of a hand of an operator on a gripping surface of a unit of power equipment and causing cessation of operation of a component of the equipment if the operator'"'"'s hand is removed from the gripping surface, the operator-sensing circuit comprising:
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a) a sensing electrode affixed to the gripping surface, a quantity of charge present on the sensing electrode having a first value if the operator'"'"'s hand overlies a portion of the sensing electrode and having a second value if the operator'"'"'s hand does not overlie the sensing electrode;
b) a charge-transfer sensor electrically coupled to the sensing electrode periodically transferring charge to the sensing electrode and sensing the quantity of charge on the sensing electrode, an output of the charge-transfer sensor generating a first output signal when the first value of the sensed charge on the sensing electrode is sensed and a second output signal, different from the first output signal, when the second value of the sensed charge on the sensing electrode is sensed; and
c) coupling circuity electrically coupled between the charge-transfer sensor and the component, the coupling circuitry causing cessation of operation of the component system when the second output signal is generated by the charge-transfer sensor. - View Dependent Claims (25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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Specification