JP4239631B2 - Combustion power tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
BACKGROUND OF THE INVENTION
The present invention relates to a combustion type power tool, and in particular, a liquefied gas sealed in a gas cylinder is injected into a combustion chamber, mixed with air, and ignited to generate power for driving a piston and to drive a nail or the like. Related to tools.
[0002]
[Prior art]
Conventional combustion-type driving tools include: housing, handle, trigger switch, head cap, combustion chamber frame, push lever, cylinder, piston, driver blade, motor, fan, gas cylinder, spark plug, exhaust check valve, magazine, tail cover And mainly. The head cap closes one end of the housing, the handle is fixed to the housing, and a trigger switch is attached. The combustion chamber frame is provided in the housing so as to be movable in the longitudinal direction of the housing and is spring-biased in the direction opposite to the head cap, but one end thereof is provided so as to be able to contact the head cap against the biasing force of the spring. .
[0003]
The push lever is movably provided at the other end of the housing and is connected to the combustion chamber frame. The cylinder is positioned so as to be able to communicate with the combustion chamber frame and is fixed to the housing, guides the movement of the combustion chamber frame, and has an exhaust hole. The piston is provided so as to be able to reciprocate with respect to the cylinder. When one end of the combustion chamber frame comes into contact with the head cap, the combustion chamber is defined together with the head cap, the combustion chamber frame, and the head cap side end of the cylinder. The driver blade extends from the anti-combustion chamber side of the piston toward the other end of the housing. The motor is supported by the head cap, and the fan is fixed to the rotating shaft of the motor and located in the combustion chamber. The fan mixes flammable gas and air in the combustion chamber to promote combustion, and when the combustion chamber frame is separated from the head cap, introduces outside air into the housing to scavenge the inside of the combustion chamber frame. It plays a role of cooling the outer peripheral side. The gas cylinder is accommodated in the housing and includes a combustible gas injected into the combustion chamber through the gas passage of the head cap. The spark plug faces the combustion chamber and ignites a mixture of combustible gas and air. The exhaust check valve selectively shields the exhaust hole.
[0004]
The magazine is provided on the other end side of the housing and accommodates fasteners such as nails. The tail cover is provided between the magazine and the push lever in order to feed the stopper in the magazine to a position facing the driver blade.
[0005]
To seal the combustion chamber when the combustion chamber frame contacts the head cap, a predetermined surface of the head cap that is in close contact with the upper portion of the combustion chamber frame, and a head cap side end portion of the cylinder that is in close contact with the lower portion of the combustion chamber frame Each is provided with a sealing material (seal ring).
[0006]
When the push lever is pressed against the workpiece and the trigger switch is turned on, the liquefied gas in the gas cylinder stored in the housing is injected into the combustion chamber with the combustion chamber defined, and the air and combustible gas are stirred by the fan. The mixture is mixed and the mixture is ignited and burned by ignition by the spark plug, and the piston is driven to drive a nail into a workpiece such as wood through a driver blade. The combustion chamber frame is kept in contact with the head cap until a predetermined time has elapsed after the explosion combustion, and the combustion chamber is sealed by closing the exhaust check valve after exhausting the combustion gas, and the temperature decreases. Due to the pressure drop in the combustion chamber, a thermal vacuum is obtained on the combustion chamber side, and the piston can be raised by the pressure difference between the upper and lower pistons (see, for example, Patent Documents 1 to 5).
[Patent Document 1]
Japanese Patent Publication No. 1-334753 [Patent Document 2]
Japanese Patent Publication No. 4-48589 [Patent Document 3]
Japanese Patent Publication No. 3-25307 [Patent Document 4]
Japanese Patent Publication No. 4-11337 [Patent Document 5]
Japanese Examined Patent Publication No. 64-9149 [0007]
[Prior art]
A feature of such a combustion type power tool is that it does not require a compressor and a hose as in a conventional compressed air type nailer, and is easy to operate.
[0008]
[Problems to be solved by the invention]
In building work that uses a combustion-type driving tool, the combustion-type driving tool is used continuously when nailing interiors such as walls and flooring in a room with relatively high airtightness and no wind flow. If used, the combustion exhaust gas may fill up the working room. This exhaust gas contains carbon monoxide, and there is a problem that the concentration of carbon monoxide increases if the worker continues to use it without noticing it.
[0009]
An object of the present invention is to obviate the above-mentioned drawbacks and prevent an increase in the concentration of carbon monoxide due to exhaust gas.
[0010]
[Means for Solving the Problems]
The above object can be achieved by providing a carbon monoxide gas sensor in the tool body to detect the carbon monoxide concentration and notifying the alarm when the set concentration is exceeded.
Further, an oxygen gas sensor may be provided to detect the concentration, and an alarm notification may be given when the concentration is lower than the set concentration.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described with reference to FIGS. 1 to 2 showing an embodiment of the present invention. FIG. 1 shows an initial state before operation. The basic configuration is almost the same as the configuration described in the section of the prior art described above, and the operation from combustion to scavenging is also almost the same as the above description, so that it will be briefly described.
[0012]
A cylinder 4 and a head cap 23 are fixed in a housing 14 forming a main body frame, and a combustion chamber frame 15 connected to the push lever 21 is urged by a spring 32 at an intermediate position thereof so as to be movable up and down. It has been. There are seals 28 and 29 above the cylinder 4 and below the head cap 23, but the flow paths 25 and 30 communicate with the outside air, and the combustion chamber 5 is not sealed. In the cylinder 4, the piston 10 to which the driver blade 16 is mounted is guided and supported, and an exhaust hole 3 in which a check valve 31 is provided outside is provided below the cylinder 4. In the combustion chamber 5, there are a fan 6 rotated by a motor 8, an injection port 22 for injecting combustible gas from a gas cylinder 7, an ignition part of a spark plug 9, and a protruding rib 24. A trigger switch 12 is provided on the handle 11 of the housing 14, and a head switch (not shown) for detecting that the tool body is pressed against the wood 27 and the combustion chamber frame 15 is at the upper end of the stroke is provided in the housing 14. Yes. The head cover 33 having the opening hole 34 is provided with a carbon monoxide gas sensor 50 such as an oxide semiconductor and a display 51 such as a lamp / buzzer.
[0013]
When the push lever 21 is pressed against the wood 27 in this state, the combustion chamber frame 15 is raised as described above, the flow paths 25 and 30 are closed by the seals 28 and 29, and the combustion chamber 5 is sealed against the atmosphere. It becomes space. In this state, first, the combustible gas in the gas cylinder 7 is injected from the injection port 22 into the combustion chamber 5 in conjunction with the rise of the combustion chamber frame 15. When the combustion chamber frame 15 reaches the uppermost end, the head switch is turned on, and then the fan 6 rotates. The combustible gas and air are turbulently mixed and stirred by the rotation of the fan 6 and the ribs 24. As shown in the block diagram of FIG. 2, when one of the head switch or the trigger switch 12 is turned on, the fan 6 starts to rotate. At the same time, the carbon monoxide gas sensor 50 starts detecting the concentration of carbon monoxide gas in the outside air coming from the opening hole 34 of the head cover 33. If the concentration exceeds a safe set concentration, light and sound from a lamp, buzzer, etc. An alarm is notified on the display 51. If it is within the set concentration, no notification is given. Next, when the other switch of the head switch or the trigger switch is turned on, the spark plug 9 is ignited by the spark ignition circuit. The piston 10 is driven downward by combustion and expansion of the air-fuel mixture, and the nail is driven into the wood 27. When the piston 10 descends to near the bottom dead center, the exhaust hole 3 of the cylinder 4 communicates with the upper chamber of the piston 10, and high-temperature and high-pressure combustion gas is exhausted to the atmosphere through the check valve 31 and the opening hole 17. The pressure in 5 falls. When this pressure decreases to atmospheric pressure, the check valve 31 is closed and sealed. The piston 10 returns to the initial position while the combustion chamber 5 is sealed by the thermal vacuum caused by the rapid cooling of the sealed space. Thereafter, when the tool body is lifted away from the wood 27 and the trigger switch 12 is turned off, the combustion chamber 5 is unsealed and opened to the atmosphere, and the fan 6 continues to rotate by the fan timer, so that the remaining combustion gas in the combustion chamber 5 is removed. After scavenging, the operation stops and the initial state shown in FIG. 1 is obtained. The air flow by the fan 6 at the time of scavenging passes through the opening hole 34 from above the head cover 33, enters the combustion chamber 5 through the fan 6 from the flow path 30, exits the combustion chamber 5 through the flow path 25, and It flows on the outer periphery and flows from the opening hole 17 below the housing 14 to the outside air.
[0014]
The carbon monoxide gas sensor 50 stops detection when the trigger switch 12 is turned off. One of the switches of the head switch or the trigger switch 12 by the operator indicating the working state starts the detection operation only when on, generates a detection signal of logic value 1 when it becomes more than a predetermined concentration.
[0015]
When the carbon monoxide gas sensor 50 issues an alarm notification on the display 51, the alarm notification is continued until the carbon monoxide gas concentration falls below a safe set concentration.
[0016]
In the above embodiment, the gas sensor 50 is a carbon monoxide gas sensor, but an oxygen gas sensor may be used. In this case, the oxygen gas concentration is the alarm notification When equal to or less than set levels.
[0017]
【The invention's effect】
According to the present invention, the carbon monoxide gas concentration or oxygen gas concentration in the outside air of the tool main body is detected, and an alarm is notified when the concentration is outside the safe set concentration, so that the carbon monoxide concentration becomes a predetermined value or more. Can be prevented.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing an initial state of an embodiment of a combustion type driving tool of the present invention.
FIG. 2 is a block diagram of the control circuit in FIG.
[Explanation of symbols]
4 is a cylinder, 5 is a combustion chamber, 6 is a fan, 7 is a gas cylinder, 8 is a motor, 9 is a spark plug, 10 is a piston, 14 is a housing, 15 is a combustion chamber frame, 33 is a head cover, 34 is an opening hole, 50 Is a carbon monoxide gas sensor, 51 is a display.

Claims (6)

A housing forming a driving tool body;
Concatenating a push lever of the tool body lower implant is supported within the housing, a vertically movable combustion chamber frame,
A push switch for detecting that the combustion chamber frame is at the upper end of the stroke;
A sealing portion for opening and closing the combustion chamber to the outside air by the vertical movement of the combustion chamber frame In the upper and lower ends of the combustion chamber frame,
A fan provided in the combustion chamber and rotated by a motor;
A gas cylinder containing a combustible gas injected into the combustion chamber;
A spark plug that ignites a mixture of combustible gas and air when one of the push switch or the trigger switch is turned on ;
It communicates with the combustion chamber in the combustion chamber below the cylinder for guiding the combustion chamber frame,
A piston movable up and down in the cylinder,
An exhaust check valve provided on the outer side of the exhaust holes and exhaust holes provided on the lower side surface of the cylinder,
Wherein in the housing downwards, a combustion type driving tool and a tail cover for feeding nails in the magazine to the piston downward,
Provided in the tool body, comprising means for detecting combustion exhaust gas and notifying means for notifying when the detected concentration exceeds a set value, and operating the detection means when one of the push switch or the trigger switch is on combustion type power tool, characterized in that cause. The combustion power tool according to claim 1, wherein the detecting means is a carbon monoxide gas sensor. 2. The combustion power tool according to claim 1, wherein the notification means is notified by an alarm sound and a lamp. The combustion power tool according to claim 1, wherein the detecting means is an oxygen gas sensor. A housing;
A combustion chamber for burning the supplied combustible gas provided in the housing;
A push switch for detecting that the combustion chamber is formed;
A combustion power tool that is driven by gas combustion in the combustion chamber when the push switch and the trigger switch are turned on ,
Gas concentration detection means provided in the tool;
Possess and informing means for informing a detection value of the gas concentration detection means,
A combustion-type power tool that operates the gas concentration detecting means when one of the push switch or the trigger switch is on . 6. The combustion type power tool according to claim 5, wherein the gas concentration detecting means detects a carbon monoxide concentration or an oxygen concentration.

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