JP2004074296A - Combustion type driving tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem of poor work efficiency wherein, in the conventional case, the opening delay of a combustion chamber until a piston is returned to an initial position after driving is executed by push-pressing a cam to a trigger switch or a screwdriver blade, therefore, continuous driving can not be performed while the trigger switch is turned on and a driving speed cannot be increased due to the resistance of the reciprocating motion of the piston. <P>SOLUTION: The opening delay of the combustion chamber 5 is executed in a manner that a combustion chamber frame 15 is locked by push-pressing, between the combustion chamber frame 15 and a housing 14 or a cylinder 4, the elastic body 62 of a locking member 61 to a solenoid 51, the step difference 55 of a sealing part 28 or the recessed groove 60 of the combustion chamber frame 15. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a combustion type driving tool for driving a piston by mixing flammable gas and air and igniting to drive a nail or the like.
[0002]
[Prior art]
Conventional combustion type driving tools of this type are disclosed, for example, in Japanese Patent Publication No. 1-34753, Japanese Patent Publication No. 4-48589, Japanese Patent Publication No. Hei 3-25307, Japanese Patent Publication No. Hei 4-11337, Japanese Patent Publication No. 64-9149, and Japanese Patent Publication No. Hei 64-9149. No. 25307646 and the like.
[0003]
FIG. 10 shows an example of the related art. A handle 11, a tail cover 1, a push lever 21, a magazine 13, and a trigger switch 12 are attached to a housing 14 that forms a main body frame, and a cylinder 4, a piston 10, a fan 6, a plug 9 , A combustible gas injection port (not shown), a gas cylinder 7, a combustion chamber frame 15, and a head cover 23 are provided. In the housing 14, the cylinder 4 and the head cover 23 are fixed to the housing 14. However, the combustion chamber frame 15 is guided by the housing 14 and the cylinder 4, and is urged downward by a spring (not shown). It is movably supported. A space closed by the combustion chamber frame 15, the head cover 23, and the piston 10 forms a combustion chamber 5 in which a mixed gas of combustible gas and air is burned. A piston 10 is movably installed in the cylinder 4 via a seal member (not shown). Below the cylinder 4, an exhaust hole (not shown) and a check valve (not shown) outside the exhaust hole, which are well-known in the pneumatic nailing machine, are provided. The combustion chamber 5 is provided with a fan 6 rotated by a motor (not shown) provided above the head cover 23 outside the combustion chamber 5, an ignition plug 9 ignited by a trigger switch 12, and a combustible gas supplied from a gas cylinder 7. Injection port, a rib 24 protruding in a projection shape, and the like. The combustion chamber frame 15 is connected to the push lever 21, and is also connected to the trigger switch 12 via the rod 202, the cam 203, and the trigger bracket 201. A magazine 13 filled with nails below the housing 14 and a tail cover 1 that feeds the nails and sets and guides the nails below the piston 10 are attached. The triangular cam 203 is swingably provided about a pivot bush 207 as a rotation axis, has an open slot 206 at one end, and locks a pivot pin 205 on the bracket 201. The other end serves as a cam projecting portion 208, which locks the rod 202.
[0004]
As shown in FIG. 10, when the push lever 21 is pressed against the wood 27, the combustion chamber frame 15 and the rod 202 move up together with the push lever 21. By raising the combustion chamber frame 15, the combustion chamber 5 closed to the outside air is formed, and thereafter, the combustible gas in the gas cylinder 7 is injected from the injection port into the combustion chamber 5 in conjunction with the combustion chamber 5, and then the fan 6 rotates, and The neutral gas and air are mixed and stirred. Further, by raising the rod 202, a clearance is formed between the lower end of the rod 202 and the projecting portion 208 of the cam 203, the cam 203 becomes rotatable, and the trigger bracket 201 connected to the cam 203 can be raised. 12 can be raised, that is, turned on. When the trigger switch 12 is turned on, the spark plug 9 sparks and ignites a mixture of combustible gas and air. The piston 10 is driven downward by the combustion and expansion of the combustible gas, and the nail in the tail cover 1 is driven into the wood 27 by the driver blade 16. When the piston 10 descends to near the bottom dead center, the exhaust hole of the cylinder 4 communicates with the upper chamber of the piston 10, the high-temperature and high-pressure combustion gas is exhausted through the check valve, and the pressure in the combustion chamber 5 decreases. At the same time, the heat of the combustion gas is transmitted and absorbed to the combustion chamber 5 and the inner wall of the cylinder 4 to be rapidly cooled, and the pressure in the combustion chamber 5 further decreases. When this pressure drops to atmospheric pressure, the check valve closes and no longer exhausts. In this state, the rapid cooling described above continues, and the upper chamber of the piston 10 becomes negative pressure (referred to as thermal vacuum), and the lower surface of the piston 10 is at atmospheric pressure. Will be returned. Thereafter, the tool body is lifted, the push lever 21 is released from the wood 27, and the trigger switch 12 is turned off. When the cam 203 rotates, the rod 202 and the combustion chamber frame 15 are also lowered, and the closed combustion chamber 5 is released to the atmosphere. Open to the public. Since the fan 6 is continuously rotating, the remaining combustion gas in the combustion chamber 5 is scavenged and replaced with fresh air, returning to the initial state where the next nail can be driven.
[0005]
One feature of this prior art is that the combustion chamber 5 cannot be opened to the atmosphere until the trigger switch 12 is turned off. Even if the tool body is now lifted from the state shown in FIG. 10 so that the push lever 21 does not come into contact with the wood 27, if the trigger switch 12 is kept on, the cam projection 208 comes into contact with the lower end of the rod 202. The lowering of the rod 202 becomes impossible. That is, the combustion chamber frame 15 connected to the rod 202 cannot be lowered, and the combustion chamber 5 maintains a closed state as in FIG. However, if the trigger switch 12 is turned off before the piston 10 returns to the initial top dead center position, the combustion chamber 5 immediately becomes atmospheric, and the negative pressure above the piston 10 returning the piston 10 disappears. 10 stops halfway without returning to the initial position. Then, at the time of the next combustion, since the volume of the combustion chamber (the volume of the upper chamber of the piston 10) is larger than the normal volume, the combustion is not performed normally, and in the case where the driving force is insufficient, the fuel may not be ignited and misfired. was there.
[0006]
Therefore, for example, in JP-A-11-216684 and JP-A-2000-334676, even if the trigger switch 12 is turned off before the piston 10 returns to the initial top dead center position, the combustion chamber 5 immediately comes into contact with the atmosphere. To prevent this, a driving tool that delays the opening of the combustion chamber 5 to the atmosphere has been proposed. 11 and 12 show a part thereof.
[0007]
FIG. 11 delays the return of the trigger switch 12 to the initial position when the trigger switch 12 is turned off, thereby delaying the opening of the combustion chamber 5 connected to the trigger switch 12 to the atmosphere, and shows the ON state of the trigger switch 12. The seal member 211 on the plunger 210 is contacted and slid in the cavity 212 provided in the trigger switch 12. When the trigger switch 12 is turned off, the trigger switch 12 is moved downward by the spring 204, and the volume of the cavity 212 below the seal member 211 is increased to a negative pressure, so that the lowering of the trigger switch 12 is delayed. Further, the descent is also slowed down by the frictional resistance of the seal member 211. As a result, the opening of the combustion chamber 5 to the atmosphere can be delayed.
[0008]
FIG. 12 shows that the cam 221 of the lockout assembly 220 is brought into contact with the tip of the driver blade 16 and the push lever 21 (work contact element) is pushed by the lockout assembly 220 until the driver blade 16, that is, the piston 10 returns to the initial position. This is to delay the release of the locked and connected combustion chamber 5 to the atmosphere.
[0009]
[Problems to be solved by the invention]
In order to improve the efficiency of nailing operation, in the case of a combustion type driving tool which enables so-called continuous driving in which the push lever 21 is repeatedly pressed and released from the wood 27 while the trigger switch 12 is turned on, the combustion shown in FIG. Since the opening delay means of the chamber 5 does not turn off the trigger switch 12, the opening delay of the combustion chamber 5 cannot be delayed. For this reason, there is a fear that an insufficient return phenomenon / misfire phenomenon of the piston 10 may be caused.
[0010]
In the opening delay means of the combustion chamber 5 shown in FIG. 12, since the cam 221 of the lockout assembly 220 is constantly pressed against the driver blade 16 of the piston 10 by a spring, the reciprocation is slowed down due to the resistance of the movement of the piston 10. However, there is a disadvantage in that the driving speed is increased and the efficiency of nailing operation is increased, which causes a reduction in efficiency. In addition, there is a problem in strength because the lockout assembly 220 is impacted and hit by the driver blade 16.
[0011]
SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks, to enable a continuous firing operation, to increase a driving speed, to improve nailing work efficiency, to reduce operator fatigue, and to improve operability. .
[0012]
[Means for Solving the Problems]
The above object can be achieved by directly locking the combustion chamber frame.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention will be described with reference to FIGS. 1 to 5 showing one embodiment of the present invention. FIG. 2 shows an initial state before the operation. The basic configuration is almost the same as that of FIG. 10, and the operation from combustion to scavenging is almost the same as that of FIG. 10. Therefore, the combustion chamber 5 is closed by pressing the tool body against the wood 27. Is shown). A cylinder 4 and a head cover 23 are fixed in a housing 14 forming a main body frame, and a combustion chamber frame 15 connected to a push lever 21 is biased by a spring (not shown) at an intermediate position between the cylinder 4 and a head cover 23 to move up and down (in FIG. (Left and right movement) is installed. Although there are seal portions 28 and 29 above the cylinder 4 (right side in the figure) and below the head cover 23 (left side in the figure), the passages 25 and 30 communicate with the outside air, and the combustion chamber 5 is closed. Absent. A piston 10 on which a driver blade 16 is mounted is guided and supported in the cylinder 4, and an exhaust hole 3 provided with a check valve 31 on the outside is provided below the cylinder 4 (to the left in the figure). 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 portion of an ignition 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) is provided in the housing 14 for detecting that the combustion chamber frame 15 is at the upper end of the stroke when the tool body is pressed against the wood 27. I have.
[0014]
A solenoid 51 facing the combustion chamber frame 15 with the shaft 52 retracted is fixed to the housing 14 on the side of the combustion chamber frame 15.
[0015]
In this state, when the trigger switch 12 is turned on, for example, in order to perform repeated firing, the fan 6 rotates. Next, when the push lever 21 is pressed against the wood 27, as shown in FIG. 3, the combustion chamber frame 15 moves up (moves rightward in the figure), and the flow passages 25, 30 are closed by the seal portions 28, 29. Thus, the combustion chamber 5 becomes a space closed to the atmosphere. In this state, first, the flammable gas in the gas cylinder 7 is injected into the combustion chamber 5 from the injection port 22, and the flammable gas and the air are mixed and stirred by the rotation of the fan 6. Next, the ignition plug 9 is ignited by an ignition circuit (not shown), and the piston 10 is driven downward (to the left in the figure) by the combustion and expansion of the air-fuel mixture, and the nail is driven into the wood 27.
[0016]
Next, based on the ignition signal, the solenoid 51 is turned on by a timer circuit (not shown) for a certain time, during which the shaft 52 protrudes to lock the combustion chamber frame 15 at this position. In this state, as shown in FIG. 1, to move to the next driving position, even if the push lever 21 is separated from the wood 27, the combustion chamber frame 15 does not move down (to the left in the figure) by the spring. , The combustion chamber 5 is kept closed. Meanwhile, the thermal vacuum allows the piston 10 to return to the initial top dead center position. The timer setting time is set longer than the time required for the piston 10 to return to the top dead center (about 100 msec depending on the driving power of the tool body). Thereafter, when the solenoid 51 is turned off, the shaft 52 is retracted, and the combustion chamber frame 15 and the push lever 21 are lowered (moved to the left in the figure) by the bias of the spring, and the combustion chamber 5 is opened to the outside air and the fan 6 is opened. Returns to the initial position while being scavenged by the rotation of.
[0017]
FIG. 4 is a block diagram of a control circuit for controlling the operation of the fan 6, the spark plug 9, and the solenoid 51, and FIG. 5 shows a time chart for explaining the operation. FIG. 5 shows an example in which two consecutive hits are performed.
[0018]
The fan 6, that is, the motor 8, starts rotating at the same time when the trigger switch 12 is turned on, and continues to rotate for a time set by the fan timer even after the trigger switch 12 is turned off. The ignition plug 9 is ignited when both the trigger switch 12 and the head switch are turned on, and the ignition causes the piston 10 to start moving.
[0019]
The solenoid 51 is energized at the same time as the ignition of the ignition plug 9 to protrude the shaft 52 to prevent the combustion frame 15 from moving, and to continue energizing for the time set by the solenoid timer. The time set by the solenoid timer is set so that the solenoid 51 maintains the biased state even after the piston 10 returns to the initial position.
[0020]
That is, the operation of the solenoid 51 causes the combustion chamber opening times T15 and T25 to be later than the piston initial position return times T14 and T24. That is, the piston can be reliably returned by the thermal vacuum. When the trigger switch 12 is turned on after pressing the push lever 21 against the wood 27, the push lever 21 is released from the wood 27 after nailing, and the trigger switch 12 is quickly turned off in a so-called single shot in which the trigger switch 12 is repeatedly turned off. However, since the same operation as above is performed reliably, there is no performance degradation due to insufficient piston return.
[0021]
6 to 9 show another embodiment of the present invention.
6 and 7 are enlarged partial cross-sectional views of the vicinity of the seal portion 28 with the cylinder 4 when the combustion chamber frame 15 is moving up (moving rightward in the figure).
FIG. 6 shows a method of locking the combustion chamber frame 15 in place of the solenoid 51 by locking between the combustion chamber frame 15 and the cylinder 4, and the combustion chamber frame forming a contact sliding surface of the seal portion 28 of the cylinder 4. A step 55 for locking is provided on the inner peripheral surface of the frame 15, and the start of the lowering (movement to the left in the figure) of the combustion chamber frame 15 is delayed by the resistance of the step 55.
[0022]
FIG. 7 shows the locking of the combustion chamber frame 15 in place of the solenoid 51 by locking between the housing 14 and the combustion chamber frame 15, and the elastic body 62 is inserted into the groove 60 of the combustion chamber frame 15 from the housing 14 side. The locking member 61 is pressed so that the start of the lowering of the combustion chamber frame 15 (movement to the left in the drawing) is delayed due to the resistance of the locking member 61 to detachment from the groove 60.
[0023]
FIG. 8 shows another example of the opening delay of the combustion chamber 5 by the solenoid 51, in which the initial position return detection sensor 70 of the piston 10 is provided near the top dead center of the piston 10, and the solenoid 51 is turned off based on the detection signal. The combustion chamber 5 is opened. FIG. 9 shows a block diagram of a control circuit for controlling the solenoid 51 and the like. The initial position return detection sensor 70 of the piston 10 includes a position detection sensor of light, magnetism, ultrasonic waves, or the like. Further, the initial position return detection sensor 70 may be configured by an acceleration sensor that detects a vibration that collides with the stopper 40 when the piston 10 returns to the top dead center.
[0024]
【The invention's effect】
According to the present invention, the opening delay of the combustion chamber is performed not by the trigger switch but by directly locking the combustion chamber frame. Therefore, it is possible to perform a continuous firing while the trigger switch is turned on. That is, since the movement of the piston is not restricted, the driving speed is increased, the efficiency of nail driving is increased, the fatigue of the operator is reduced, and the operability can be improved.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view illustrating an operation of an embodiment of a combustion type driving tool according to the present invention.
FIG. 2 is a partial cross-sectional view showing an initial state of FIG. 1;
FIG. 3 is a partial sectional view showing another operation of FIG. 1;
FIG. 4 is a block diagram of a control circuit for controlling the operation of the solenoid shown in FIGS.
FIG. 5 is a time chart for explaining the operation of FIG. 4;
FIG. 6 is an enlarged partial sectional view showing a main part of another embodiment of the combustion type driving tool of the present invention.
FIG. 7 is an enlarged partial sectional view showing a main part of still another embodiment of the combustion type driving tool of the present invention.
FIG. 8 is a partial cross-sectional view showing an initial state of another embodiment of the combustion type driving tool of the present invention.
FIG. 9 is a block diagram of a control circuit that controls the operation of the solenoid of FIG. 8;
FIG. 10 is a partial cross-sectional view showing an operation of an example of a conventional combustion driving tool.
FIG. 11 is a partial cross-sectional view showing a main part of another example of the conventional combustion driving tool.
FIG. 12 is a configuration explanatory view showing a main part of still another example of the conventional combustion driving tool.
[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, 15 is a combustion chamber frame, 51 is a solenoid, 52 is a shaft, 55 is a step, and 60 is a step. A concave groove, 61 is a locking member, 62 is an elastic body, 70 is a piston return detection sensor.

Claims (8)

A housing forming the driving tool body, a combustion chamber frame supported in the housing and connected to a push lever below the driving tool body and capable of moving up and down, and a vertical movement of the combustion chamber frame at upper and lower ends of the combustion chamber frame. A seal portion that opens and closes the combustion chamber against outside air, a fan provided in the combustion chamber and rotated by a motor, a gas cylinder containing flammable gas injected into the combustion chamber, and a mixture of flammable gas and air A spark plug that ignites air, a cylinder that communicates with the combustion chamber below the combustion chamber, and guides the combustion chamber frame, a piston that is vertically movably supported within the cylinder, and an exhaust hole that is provided on a lower side surface of the cylinder. A combustion type driving tool comprising: an exhaust check valve provided outside the exhaust hole; and a tail cover that feeds a nail in a magazine below the piston below the housing,
A combustion type driving tool wherein the opening of the combustion chamber to the outside air is delayed by directly locking the combustion chamber frame until the piston returns to the initial position after being driven. The combustion type driving tool according to claim 1, wherein the combustion chamber frame is locked by a solenoid. The combustion type driving tool according to claim 2, wherein the locking of the combustion chamber frame is performed by setting a time of a timer circuit and controlling a solenoid. The combustion type driving tool according to claim 1, wherein the locking of the combustion chamber frame is performed by pressing a locking member into a concave groove on a side surface of the combustion chamber frame with an elastic body. The combustion type driving tool according to claim 1, wherein the locking of the combustion chamber frame is performed by locking a seal portion at upper and lower ends of the combustion chamber frame. A housing forming the driving tool body, a combustion chamber frame supported in the housing and connected to a push lever below the driving tool body and capable of moving up and down, and a vertical movement of the combustion chamber frame at upper and lower ends of the combustion chamber frame. A seal portion that opens and closes the combustion chamber against outside air, a fan provided in the combustion chamber and rotated by a motor, a gas cylinder containing flammable gas injected into the combustion chamber, and a mixture of flammable gas and air A spark plug that ignites air, a cylinder that communicates with the combustion chamber below the combustion chamber, and guides the combustion chamber frame, a piston that is vertically movably supported within the cylinder, and an exhaust hole that is provided on a lower side surface of the cylinder. A combustion type driving tool comprising: an exhaust check valve provided outside the exhaust hole; and a tail cover that feeds a nail in a magazine below the piston below the housing,
A combustion type driving tool, characterized in that the opening of the combustion chamber to the atmosphere is delayed by controlling a piston return detection sensor and a solenoid until the piston returns to an initial position after being driven. The combustion type driving tool according to claim 6, wherein the piston return detection sensor is performed by a position detection sensor such as light, magnetism, or ultrasonic wave provided at a position for detecting an initial piston position. The combustion type driving tool according to claim 6, wherein the piston return detection sensor is a vibration acceleration sensor that detects a vibration acceleration when the piston returns to the initial position.

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