JP2005046976A - Firing control device of gas combustion type impact tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent firing from being performed by a firing device when the temperature of a gas container is increased over a specified set value. <P>SOLUTION: In this gas combustion type impact tool, an inflammable gas is fed from a gas container 20 filled with the inflammable gas into a combustion chamber 10 to generate a mixed gas of air and a combustion gas in the combustion chamber 10, and a firing device 25 is energized to burn the mixed gas in the combustion chamber 10 to generate a high-pressure combustion gas in the combustion chamber 10. A temperature detector 33 detecting the ambient temperature of the gas container 20 is installed, and the temperature detected by the temperature detector 33 is compared with a pre-set set temperature. When the temperature around the gas container 20 is higher than the set temperature, the energization of the firing device 25 is cut out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In the present invention, a combustible gas and air are mixed in a combustion chamber formed above a striking cylinder to generate a mixed gas, and a spark is generated in the combustion chamber to ignite and burn the mixed gas. The present invention relates to an ignition control device for a gas combustion type impact tool in which a striking piston accommodated in a striking cylinder is driven by combustion gas generated in a combustion chamber.

  As an example of a gas combustion type impact tool, a combustible gas is injected into a sealed combustion chamber to generate a mixed gas of combustible gas and air in the combustion chamber, and a discharge spark is generated by an igniter in the combustion chamber. The mixed gas is ignited and combusted, and the high-pressure combustion gas generated in the combustion chamber is applied to the striking piston accommodated in the striking cylinder to drive the striking piston in an impact cylinder. 2. Description of the Related Art A combustion gas driven nailer is known in which a nail is driven into a steel plate or concrete by a driver coupled to a lower surface side. In such a combustion gas driven nailer, a gas container filled with a combustible gas is installed in the tool, and a battery, which is an igniter power source for igniting the combustible gas, is installed in the tool. The tool is formed as a possible tool and can be driven into a nail or a pin without being restricted by a power supply source such as electric power or compressed air.

In the conventional combustion gas driven nail driver, an annular combustion chamber is formed in the upper part of the impact cylinder accommodated in the housing, and the combustible so as to be substantially parallel to the impact cylinder in the same housing. A gas container filled with gas is installed. The combustion chamber is formed with an injection nozzle for injecting the combustible gas filled in the gas container into the combustion chamber, and further combusts the combustible gas injected into the combustion chamber by the injection nozzle. A rotary fan is formed for mixing with indoor air to generate a mixed gas having a predetermined air-fuel ratio. The gas container is filled with a liquefied gas such as butane gas, and a constant amount is supplied to the combustion chamber by the pressure of the gas vaporized in the gas container, and is constant by being stirred with the air in the combustion chamber. An air / fuel ratio mixed gas is generated.
Japanese Patent Publication No. 3-25307

  Furthermore, an igniter is formed in the combustion chamber for igniting and explosively burning the mixed gas generated in the combustion chamber by generating a spark in the combustion chamber. The igniter is formed by a spark plug or the like that boosts the voltage of the battery mounted on the nailing machine to a high voltage and generates a discharge spark when this high voltage is energized. When the operator operates the trigger formed at the base of the grip portion formed integrally with the housing, a high voltage is applied to the igniter to generate a spark in the combustion chamber, thereby generating a spark in the combustion chamber. The nailing machine is driven by igniting the mixed gas.

  By the way, in the gas combustion type impact tool as described above, the tool may be used in the midsummer hot sun, left in the sun under the sun, or in the trunk of a car parked under the hot sun. The entire tool may become hot due to being stored in the container. Thus, when the whole tool becomes high temperature, the gas container mounted in the tool also becomes high temperature, and the pressure of the vaporized gas in the gas container may increase. When the pressure in the gas container becomes high in this way, a combustible gas of a specified amount or more is supplied into the combustion chamber due to the high pressure, and a mixed gas with a predetermined air-fuel ratio cannot be generated. There is a risk that it may not be possible to do so, or that combustion at an unplanned scale occurs. Furthermore, since the gas pressure increases, the combustible gas leaks from the path from the gas container to the injection nozzle, and the combustible gas staying in the housing is ignited by the spark of the igniter, causing an unexpected accident. There was a fear.

  In the present invention, when the temperature of the gas container itself filled with the combustible gas or the temperature around the gas container becomes higher than a predetermined set temperature value, the combustion of the ignition device is interrupted by shutting off the discharge voltage. It is an object of the present invention to provide an ignition control device for a gas combustion type impact tool that prevents discharge in a room.

  In order to solve the above problems, an ignition control device for a gas-fired impact tool according to the present invention accommodates a gas container filled with a combustible gas in a main body, and the combustible gas of the gas container is formed above a striking cylinder. The combustion gas is supplied to the combustion chamber to generate a mixed gas of air and combustion gas, and the ignition device is energized to ignite and burn the mixed gas in the combustion chamber, and the combustion gas pressure generated in the combustion chamber is reduced. A gas combustion type impact tool which acts on a striking piston accommodated in the striking cylinder to drive the striking piston in a shocking manner, and a temperature detector for detecting the ambient temperature of the gas container is provided. The detected temperature value of the gas container is input to the control device, and the detected temperature value of the temperature detector is compared with a preset temperature value set by the control device. Ri high time to, is characterized in that so as to cut off the power supply to the ignition device.

  According to the present invention, the temperature detector for detecting the ambient temperature of the gas container mounted on the tool is provided, and the detection output of the temperature detector is input to the control circuit, and the detection of the temperature detector is performed by the control circuit. The temperature is compared with the preset temperature, and when the temperature around the gas container is higher than the set temperature, the discharge voltage to the ignition device is cut off. Thus, when a mixed gas that is not a predetermined air-fuel ratio is generated in the combustion chamber, the mixed gas is not ignited, and the danger of combustion at an unplanned scale can be avoided. Further, it is possible to prevent an accident that the combustible gas leaking from the path from the gas container to the injection nozzle and staying in the housing is ignited by the spark of the ignition device.

  When the temperature of the gas container itself filled with flammable gas or the surrounding temperature of the gas container becomes higher than a predetermined set value, the energization to the ignition device is cut off to prevent discharge in the combustion chamber. A temperature detector for detecting the ambient temperature of the gas container is provided, and the detected temperature value of this temperature detector is input to a control device that controls energization to the ignition device, and the detected temperature value is detected by the control device. Is compared with the set temperature value, and when the detected temperature value is higher than the set temperature value, control is performed by the control device so that the energization to the igniter is cut off.

  FIG. 1 shows a combustion gas driven nail driver showing an embodiment of a gas combustion type impact tool according to the present invention. As shown in FIG. 1, the combustion gas driven nail driver 1 has a grip portion 3 facing rearward. A striking cylinder 4 is accommodated in a housing 2 in which a striking piston 5 in which a driver 6 for striking a nail is coupled to the lower surface side is slidably accommodated. Yes. A nose portion 7 is formed on the lower portion of the housing 2 to form an injection port 8 for driving and guiding a nail toward a driven material. A driver 6 coupled to the striking piston 5 is attached to the nose portion. 7 slidably accommodated in the injection port 8 and guided. A magazine 9 loaded with a large number of nails is connected to the rear side of the nose portion 7, and the nails in the magazine 9 are sequentially supplied into the injection port 8 of the nose portion 7 and supplied into the injection port 8. The nail thus struck is struck by the driver 6 and driven out from the injection port 8 onto the workpiece.

  A combustion chamber 10 for generating a mixed gas of combustible gas and air and burning the mixed gas is formed above the impact cylinder 4. The combustion chamber 10 is disposed between the upper end of the impact cylinder 4 to which the upper end surface of the impact piston 5 is exposed and the upper wall 12 formed inside the upper housing 11 formed at the upper portion of the housing 2. The annular movable sleeve 13 is formed by supplying a combustible gas into the combustion chamber 10 to generate a mixed gas with air, and combusting the combustible gas in the sealed combustion chamber 10. The pressure of the generated combustion gas is applied to the striking piston 5 to drive the striking piston 5 to the bumper 14 disposed at the bottom dead center in the striking cylinder 4.

  The movable sleeve 13 forming the combustion chamber 10 is slidably arranged along the operating direction of the striking piston 5, and before starting the nail driver 1, the movable sleeve 13 is arranged at the lower position. The inside of the combustion chamber 10 is communicated with the atmosphere via an air vent 15 formed in the upper housing 11 and an exhaust passage 16 formed between the outer peripheral surface of the impact cylinder 4 and the inner peripheral surface of the housing 2. Further, when starting the nailing machine, as shown in FIG. 2, the movable sleeve 13 is moved to the upper position, and the upper end and the lower end of the movable sleeve 13 are disposed on the upper wall and the impact is made. The combustion chamber 10 is shielded from the atmosphere by being brought into close contact with an O-ring 18 disposed on the outer periphery of the cylinder 4.

  A housing portion 19 for housing a gas container 20 filled with a combustible gas is formed in the housing 2 at the side of the striking cylinder 4, and is connected to the gas container 20 mounted in the housing portion 19. An injection nozzle 21 for injecting combustible gas into the combustion chamber 10 through the supply path 22 is formed facing the combustion chamber 10. As shown in FIG. 2, after moving the movable sleeve 13 forming the combustion chamber 10 upward to shut off the combustion chamber 10 from the atmosphere, the inside of the gas container 20 is caused by the vaporization pressure in the gas container 20. A certain amount of the combustible gas is jetted into the combustion chamber 10 through the supply path 22.

  A rotation fan 24 that is rotated by an electric motor 23 is formed in the combustion chamber 10, and the combustible gas injected into the combustion chamber 10 by the injection nozzle 21 is agitated with the air in the combustion chamber 10. Thus, a mixed gas having a predetermined air-fuel ratio is generated in the combustion chamber 10. Further, an ignition device 25 is formed in the combustion chamber 10 for igniting and burning the mixed gas generated by stirring in the combustion chamber 10 by the rotary fan 24. The ignition device 25 generally generates sparks by boosting the voltage of the battery 26 attached to the rear end of the grip portion 3 to a high voltage and discharging the high voltage in the combustion chamber 10. An igniter, a spark plug, or the like is used. A spark is generated in the combustion chamber 10 in which the mixed gas is generated, so that the mixed gas is ignited and burned, and high-pressure combustion gas is generated in the combustion chamber 10. It is made to generate with.

  A control device 27 for driving and controlling the ignition device 25 for igniting the mixed gas in the combustion chamber 10 is accommodated in the grip portion 3 formed integrally with the housing 2. The control device 27 is configured to discharge electric power from the battery 26 attached to the rear end portion of the grip portion 3 based on a signal of a trigger switch 29 operated by a trigger 28 formed at the base portion of the grip portion 3. Is supplied to the ignition device 25.

  As shown in the block diagram of FIG. 3, the electric power supplied from the battery 26 is supplied to the ignition device 25 via a switching circuit 30 constituted by FET elements formed on the control device 27. The trigger switch 29 operated by the trigger 28 is connected to a timer circuit 31 formed on the control device 27. When the trigger switch 29 is turned ON, the trigger signal 31a output from the timer circuit 31 is It is connected so as to be input to the switching circuit 30. As described above, when the trigger signal 31a from the timer circuit 31 is input to the switching circuit 30, discharge power is supplied to the ignition device 25, and a spark is generated in the combustion chamber 10 to burn the mixed gas. Done.

  Further, a comparison circuit 32 is formed on the control device 27, and this comparison circuit 32 is constituted by a thermistor element or the like installed in the vicinity of the gas container 20 accommodated in the accommodating portion 19. The detection output signal 33a of the temperature detector 33 is input. The comparison circuit 32 compares a preset set temperature value with the detection value of the temperature detector 33, and outputs a reset signal 32a to the timer circuit 31 when the detected temperature value is higher than the set temperature value. I am doing so. When the reset signal 32 a from the comparison circuit 32 is input to the timer circuit 31, the timer circuit 31 is reset, and the trigger signal 31 a is output from the timer circuit 31 even when the trigger 28 is operated and the trigger switch 29 is turned on. Is not output.

  The operation of the ignition control apparatus of the above embodiment will be described with reference to the flowchart shown in FIG. When the nail driver 1 is turned on, power is supplied to the control device 27 in step 1, and the detected temperature value input from the temperature detector 33 and the set temperature value are compared in step 2 by the comparison circuit 32. If the detected temperature value is lower than the set temperature value, the process proceeds to step 3 to set the timer circuit 31 and reset the warning display. Further, the process proceeds to step 4 to check whether or not the trigger 28 is operated and the trigger switch 29 is operated. If the trigger switch 29 is not operated at this time, the process returns to step 2 and the temperature detector 33 is set again. The detected temperature is compared with the set temperature. When the trigger switch 29 is turned on in step 4, the timer circuit 31 is started and the trigger signal 31a is output from the timer circuit 31 to the switching circuit 30. In step 5, the switching circuit 30 is turned on. In step 6, the ignition device 25 is discharged. Electric power is energized and discharge is performed to ignite the mixed gas in the combustion chamber 10. After driving the striking piston with the combustion gas in the combustion chamber, the control device 27 proceeds to the next process such as returning the striking piston to the top dead center and exhausting the combustion gas in the combustion chamber.

  When the detected temperature value input from the temperature detector 33 by the comparison circuit 32 and the set temperature value are compared by the comparison circuit in the step 2, and the detected temperature value becomes higher than the set temperature value, the process proceeds to the step 7. Then, the timer circuit 31 is reset to turn on a warning lamp or generate an alarm sound indicating that the temperature around the gas container 20 is abnormally high and dangerous, and then go to step 2 again. The return detection temperature value is compared with the set temperature value. By resetting the timer circuit 31 in step 7, the trigger signal 31a from the timer circuit 31 to the switching circuit 30 is prevented from being output. Therefore, even if the trigger 28 is operated by the operator and the trigger switch 29 is turned on. The switching circuit 30 remains OFF, and the electric power for discharge to the ignition device 25 is not energized, and the combustible gas is not ignited.

1 is a longitudinal side view of a combustion gas driven nailer according to an embodiment of a gas combustion type impact tool of the present invention. Longitudinal side view of enlarged main part of combustion gas driven nailer with combustion chamber closed FIG. 1 is a block diagram of an ignition control device for the gas combustion type impact tool of FIG. Flowchart diagram of the ignition control device of the gas combustion type impact tool of FIG.

Explanation of symbols

1 Combustion gas driven nailer (gas fired impact tool)
DESCRIPTION OF SYMBOLS 10 Combustion chamber 20 Gas container 25 Ignition device 27 Control device 29 Trigger switch 30 Switching circuit 31 Timer circuit 32 Comparison circuit 33 Temperature detector

Claims (1)

A gas container filled with a combustible gas is housed in the main body, and the combustible gas in the gas container is supplied into a combustion chamber formed above the striking cylinder to generate a mixed gas of air and combustion gas in the combustion chamber. Then, by energizing the ignition device, the mixed gas in the combustion chamber is ignited and combusted, and the combustion gas pressure generated in the combustion chamber is applied to the striking piston accommodated in the striking cylinder to shock the striking piston. In a gas combustion type impact tool that is driven, a temperature detector that detects the ambient temperature of the gas container is provided, and the temperature detected by the temperature detector is input to the control device, and the temperature detector is detected by the control device. The temperature value is compared with a preset temperature value, and when the temperature around the gas container is higher than the preset temperature, the energization to the ignition device is cut off. Ignition control device for a gas combustion type impact tool according to.

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