System for controlling energy output of combustion-powered, fastener-driving tool
First Claim
1. In combination, a combustion-powered, fastener-driving tool exhibiting an energy output, and a system for controlling said energy output of said tool, comprising:
- a combustion chamber defined within said combustion-powered, fastener-driving tool;
fan means disposed within said combustion chamber of said tool for producing turbulence within said combustion chamber of said tool when said fan means is driven;
motor means for driving said fan means when a driving voltage is applied across said motor means;
battery means for providing said driving voltage to said motor means; and
circuit means, for controlling said energy output of said tool by controlling the speed of said fan means, comprising first means for providing a setpoint voltage, and second means, including a comparator, for sampling a voltage proportional to said speed of said fan means, comparing said sampled voltage to said setpoint voltage, and selectively applying said driving voltage across said motor means if said sampled voltage is less than said setpoint voltage and terminating said driving voltage to said motor means if said sampled voltage is not less than said setpoint voltage.
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Accused Products
Abstract
A system for controlling the energy output of a combustion-powered, fastener-driving tool in which a fan is arranged to produce turbulence in a combustion chamber when the fan is driven, in which a direct current motor is arranged to drive the fan when a driving voltage is applied across the motor, and in which a battery provides a battery voltage not less than the driving voltage. A voltage divider includes a settable resistance, either a potentiometer or two parallel, fixed resistances that can be alternatively selected, and is used to provide a setpoint voltage. A comparator, an inverter, and a transistor switch are arranged to sample a voltage proportional to the rotational speed of the fan, to compare the sampled voltage to the setpoint voltage, to apply the driving voltage across the motor if the sampled voltage is less than the setpoint voltage, and to remove the driving voltage from across the motor if the sampled voltage is not less than the setpoint voltage. The voltage divider also includes a permanently grounded resistance, two selectively groundable resistances, and two photoelectric switches, each including a phototransmissive diode and a photoreceptive transistor and being arranged to ground one of the selectively groundable resistances if a fastener between the phototransmissive diode and the photoreceptive transistor blocks phototransmission therebetween but not if the fastener does not block phototransmission therebetween. The photoelectric switches can thus be used for discriminating among relatively short, intermediate-length, and relatively long fasteners.
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Citations
20 Claims
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1. In combination, a combustion-powered, fastener-driving tool exhibiting an energy output, and a system for controlling said energy output of said tool, comprising:
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a combustion chamber defined within said combustion-powered, fastener-driving tool; fan means disposed within said combustion chamber of said tool for producing turbulence within said combustion chamber of said tool when said fan means is driven; motor means for driving said fan means when a driving voltage is applied across said motor means; battery means for providing said driving voltage to said motor means; and circuit means, for controlling said energy output of said tool by controlling the speed of said fan means, comprising first means for providing a setpoint voltage, and second means, including a comparator, for sampling a voltage proportional to said speed of said fan means, comparing said sampled voltage to said setpoint voltage, and selectively applying said driving voltage across said motor means if said sampled voltage is less than said setpoint voltage and terminating said driving voltage to said motor means if said sampled voltage is not less than said setpoint voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In combination, a combustion-powered, fastener-driving tool exhibiting an energy output, and a system for controlling said energy output of said tool, comprising:
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a combustion chamber defined within said combustion-powered, fastener-driving tool; fan means disposed within said combustion chamber of said tool for producing turbulence within said combustion chamber of said tool when said fan means is driven; motor means for driving said fan means when a driving voltage is applied across said motor means; battery means for providing said driving voltage to said motor means; and circuit means, for controlling said energy output of said tool by controlling the rotational speed of said fan means, comprising first means for providing a setpoint voltage, and second means, including a comparator, for sampling a voltage proportional to said rotational speed of said fan means, comparing said sampled voltage to said setpoint voltage, and selectively applying said driving voltage across said motor means if said sampled voltage is less than said setpoint voltage and terminating said driving voltage to said motor means if said sampled voltage is not less than said setpoint voltage, wherein said first means for providing said setpoint voltage comprises permanently connected resistances and a selectively connectable resistance, and said circuit means further comprises a photoelectric switch including a phototransmissive diode and a photoreceptive transistor which are arranged to connect said selectively connectable resistance to said first means for providing said setpoint voltage if phototransmission between said phototransmissive diode and said photoreceptive transistor is not blocked, but not to connect said selectively connectable resistance to said first means for providing said setpoint voltage if phototransmission between said phototransmissive diode and said photoreceptive transistor is blocked. - View Dependent Claims (12, 13, 19)
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14. In combination, a combustion-powered, fastener-driving tool exhibiting an energy output, and a system for controlling said energy output of said tool, comprising:
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a combustion chamber defined within said combustion-powered, fastener-driving tool; fan means disposed within said combustion chamber of said tool for producing turbulence within said combustion chamber of said tool when said fan means is driven; motor means for rotating said fan means when a driving voltage is applied across said motor means; battery means for providing said driving voltage to said motor means; and circuit means, for controlling said energy output of said tool by controlling the rotational speed of said fan means, comprising first means for providing a setpoint voltage, and second means, including a comparator, for sampling a voltage proportional to said rotational speed of said fan means, comparing said sampled voltage to said setpoint voltage, and selectively applying said driving voltage across said motor means if said sampled voltage is less than said setpoint voltage and terminating said driving voltage to said motor means if said sampled voltage is not less than said setpoint voltage, wherein said first means comprises a selectively connectable resistance, and said circuit means further comprises a photoelectric switch including a phototransmissive diode and a photoreceptive transistor which are arranged to connect said selectively connectable resistance to said first means if phototransmission between said phototransmissive diode and said photoreceptive transistor is not blocked by a fastener to be driven by said tool, but not to connect said selectively connectable resistance to said first means if phototransmission between said phototransmissive diode and said photoreceptive transistor is blocked by a fastener to be driven by said tool whereby said tool can be used to drive fasteners having a predetermined length. - View Dependent Claims (15, 16, 17, 18, 20)
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Specification