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A combustion-powered driving tool for driving nails or other fasteners in which the starting characteristics of a motor in the tool are improved by varying the amount of voltage applied to the motor when starting the motor and during normal operations so that the motor is driven to reach the rotatio

A combustion-powered driving tool for driving nails or other fasteners in which the starting characteristics of a motor in the tool are improved by varying the amount of voltage applied to the motor when starting the motor and during normal operations so that the motor is driven to reach the rotational speed required in normal operations quickly. Therefore, the combustion-powered driving tool does not require the use of an expensive low-inertia motor, but can use a relatively inexpensive core-type motor or the like with inferior starting characteristics, while improving the work efficiency and user-friendliness of the combustion-powered driving tool.

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1. A combustion-powered driving tool for driving fasteners into a workpiece, comprising:a housing having a first end and a second end opposite the first end;a head section for fixing to the first end of the housing and having a flammable gas channel formed therein;a motor;a battery for supplying an

1. A combustion-powered driving tool for driving fasteners into a workpiece, comprising:a housing having a first end and a second end opposite the first end;a head section for fixing to the first end of the housing and having a flammable gas channel formed therein;a motor;a battery for supplying an operating voltage;a motor drive controlling section that is supplied with the operating voltage of the battery and controls a voltage applied to the motor;a cylinder;a piston slidably movably disposed inside the cylinder;a combustion chamber frame that moves to contact and separate from the head section and that forms a combustion chamber together with the head section, the cylinder, and the piston when the combustion chamber frame is in contact with the head section;a fan rotatably disposed in the combustion chamber and driven to rotate by the motor; anda sparkplug exposed in the combustion chamber for igniting a mixture of air and flammable gas in the combustion chamber, the flammable gas being supplied into the combustion chamber via the flammable gas channel, wherein explosive combustion caused by firing of the sparkplug moves the piston toward the second end of the housing and a fastener is driven into the workpiece in accordance with the movement of the piston,wherein the motor drive control section applies a first voltage to the motor when the combustion chamber is formed by the combustion chamber frame moving toward and brought into contact with the head section, and a second voltage to the motor, the first voltage being greater than the second voltage.2. The combustion-powered driving tool according to claim 1, wherein the motor drive controlling section comprises an up converter that steps up the operating voltage of the battery and outputting a stepped up voltage, wherein the motor drive controlling section applies the stepped up voltage to the motor as the first voltage.3. The combustion-powered driving tool according to claim 2, wherein the motor drive controlling section applies the operating voltage of the battery to the motor as the second voltage.4. The combustion-powered driving tool according to claim 1, wherein the motor drive controlling section comprises a down converter that steps down the operating voltage of the battery and outputting a stepped down voltage, wherein the motor drive controlling section applies the stepped down voltage to the motor as the second voltage.5. The combustion-powered driving tool according to claim 4, wherein the motor drive controlling section applies the operating voltage of the battery to the motor as the first voltage.6. The combustion-powered driving tool according to claim 1, wherein with the first voltage applied to the motor, the motor reaches to the steady rotational speed within 130 ms.7. The combustion-powered driving tool according to claim 1, wherein the motor drive control section applies a third voltage to the motor after the explosive combustion is taken place, the second voltage being greater than the third voltage.8. A combustion-powered driving tool for driving fasteners into a workpiece, comprising:a housing having a first end and a second end opposite the first end;a head section for fixing to the first end of the housing and having a flammable gas channel formed therein;a motor;a battery for supplying an operating voltage;a power source section that is supplied with the operating voltage of the battery and generates a reference voltage;a motor drive controlling section that is supplied with the operating voltage of the battery and the reference voltage from the power source section and that drives the motor based on the operating voltage and the reference voltage;a first switch that detects whether the tool is pressed against the workpiece and outputs a first signal indicative of a detected condition;a second switch that instructs driving the fastener into the workpiece and outputs a second signal indicative of an instruction to drive the fastener;a cylinder;a piston slidably movably disposed inside the cylinder;a combustion chamber frame that moves to contact and separate from the head section and that forms a combustion chamber together with the head section, the cylinder, and the piston when the combustion chamber frame is in contact with the head section;a fan rotatably disposed in the combustion chamber and driven to rotate by the motor;a sparkplug exposed in the combustion chamber for igniting a mixture of air and flammable gas in the combustion chamber, the flammable gas being supplied into the combustion chamber via the flammable gas channel, wherein explosive combustion caused by firing of the sparkplug moves the piston toward the second end of the housing and a fastener is driven into the workpiece in accordance with the movement of the piston; anda controller that controls the power source section not to generate the reference voltage in order to reduce power consumption when at least one of the first signal and the second signal indicates that the tool is left unused for a prescribed period of time.9. The combustion-powered driving tool according to claim 8, wherein the controller further controls the power source section not to generate the reference voltage in order to reduce power consumption when at least one of the first signal and the second signal indicates that at least one of the first switch and the second switch malfunctions.10. The combustion-powered driving tool according to claim 8, wherein the motor drive control section applies a first voltage to the motor when the combustion chamber is formed by the combustion chamber frame moving toward and brought into contact with the head section, and a second voltage to the motor after the motor has reached a steady rotational speed, the first voltage being greater than the second voltage.11. The combustion-powered driving tool according to claim 10, wherein the motor drive control section applies a third voltage to the motor after the explosive combustion is taken place, the second voltage being greater than the third voltage.12. A combustion-powered driving tool for driving fasteners into a workpiece, comprising:a housing having a first end and a second end opposite the first end;a head section for fixing to the first end of the housing and having a flammable gas channel formed therein;a motor;a battery for supplying an operating voltage;a power source section that is supplied with the operating voltage of the battery;a motor drive controlling section that is supplied with the operating voltage of the battery and drives the motor;a first switch that detects whether the tool is pressed against the workpiece and outputs a first signal indicative of a detected condition;a second switch that instructs driving the fastener into the workpiece and outputs a second signal indicative of an instruction to drive the fastener;a cylinder;a piston slidably movably disposed inside the cylinder;a combustion chamber frame that moves to contact and separate from the head section and that forms a combustion chamber together with the head section, the cylinder, and the piston when the combustion chamber frame is in contact with the head section;a fan rotatably disposed in the combustion chamber and driven to rotate by the motor;a sparkplug exposed in the combustion chamber for igniting a mixture of air and flammable gas in the combustion chamber, the flammable gas being supplied into the combustion chamber via the flammable gas channel, wherein explosive combustion caused by firing of the sparkplug moves the piston toward the second end of the housing and a fastener is driven into the workpiece in accordance with the movement of the piston; anda controller that actuates the sparkplug to ignite the mixture of air and flammable gas in the combustion chamber in response to the second signal and regardless of the first signal.13. A combustion-powered driving tool for driving fasteners into a workpiece, comprising:a housing having a first end and a second end opposite the first end;a head section for fixing to the first end of the housing and having a flammable gas channel formed therein;a motor;a battery for supplying an operating voltage;a power source section that is supplied with the operating voltage of the battery and generates a reference voltage;a motor drive controlling section that is supplied with the operating voltage of the battery and the reference voltage from the power source section and that drives the motor based on the operating voltage and the reference voltage;a first switch that detects whether the tool is pressed against the workpiece and outputs a first signal indicative of a pressed condition of the tool;a second switch that instructs driving the fastener into the workpiece and outputs a second signal indicative of an instruction to drive the fastener;a third switch that connects the battery and the power source section when turned ON;a cylinder;a piston slidably movably disposed inside the cylinder;a combustion chamber frame that moves to contact and separate from the head section and that forms a combustion chamber together with the head section, the cylinder, and the piston when the combustion chamber frame is in contact with the head section;a fan rotatably disposed in the combustion chamber and driven to rotate by the motor;a sparkplug exposed in the combustion chamber for igniting a mixture of air and flammable gas in the combustion chamber, the flammable gas being supplied into the combustion chamber via the flammable gas channel, wherein explosive combustion caused by firing of the sparkplug moves the piston toward the second end of the housing and a fastener is driven into the workpiece in accordance with the movement of the piston; anda controller that is supplied with the reference voltage from the power source section when the third switch is ON, wherein the controller is rendered inoperative when neither the first signal nor the second signal is output even if the third switch is ON.14. A combustion-powered driving tool for driving fasteners into a workpiece, comprising:a housing having a first end and a second end opposite the first end;a head section for fixing to the first end of the housing and having a flammable gas channel formed therein;a motor;a battery for supplying an operating voltage; a power source section that is supplied with the operating voltage of the battery and generates a reference voltage;a motor drive controlling section that is supplied with the operating voltage of the battery and the reference voltage from the power source section and that drives the motor based on the operating voltage and the reference voltage;a first switch that detects whether the tool is pressed against the workpiece and outputs a first signal indicative of a pressed condition of the tool;a second switch that instructs driving the fastener into the workpiece and outputs a second signal indicative of an instruction to drive the fastener;a cylinder;a piston slidably movably disposed inside the cylinder;a combustion chamber frame that moves to contact and separate from the head section and that forms a combustion chamber together with the head section, the cylinder, and the piston when the combustion chamber frame is in contact with the head section;a fan rotatably disposed in the combustion chamber and driven to rotate by the motor;a sparkplug exposed in the combustion chamber for igniting a mixture of air and flammable gas in the combustion chamber, the flammable gas being supplied into the combustion chamber via the flammable gas channel, wherein explosive combustion caused by firing of the sparkplug moves the piston toward the second end of the housing and a fastener is driven into the workpiece in accordance with the movement of the piston; anda controller that generates a start signal instructing to drive a fastener into the workpiece, wherein the fastener is driven into the workpiece when both the second signal and the start signal are generated.