JP4046470B2 - Nailer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nailing machine for driving a stopper such as a nail, and exhausts compressed air to be discharged out of a main body through a pressure reducing mechanism.
[0002]
[Prior art]
To reduce the exhaust pressure and exhaust noise of pneumatic tools driven by compressed air, expand the compressed air in the expansion chamber and reduce the pressure, restrict the flow rate of the compressed air with the throttle valve, and reduce the pressure. There are a method of reducing pressure by passing resistance through a muffler such as a material, a method of rectifying and reducing turbulent flow such as vortex, and a method of reducing and reducing sound by canceling the opposite wavelengths together.
[0003]
In general, the compressed air discharged from the nailing machine includes compressed air above the piston of the cylinder at the bottom dead center of the piston, compressed air supplied to and discharged from the head valve chamber to operate the head valve, and head valve. There is compressed air that is supplied to and discharged from the valve piston lower chamber in the trigger valve.
[0004]
The nailing machine shown in FIG. 9 has two expansion chambers 21, 23 in the handle 18, a throttle passage 22 for reducing the passage area is provided between the expansion chambers 21, 23, and the rear of the expansion chamber 23. Is provided with a throttle passage 24 for reducing pressure by repeatedly limiting the flow rate of expansion and compressed air. An exhaust string 30 is provided at the rear end of the handle 18, and the compressed air that has passed through the throttle passage 24 passes through a muffler 31 made of a porous material or the like, and is further depressurized and rectified to be released to the atmosphere.
[0005]
The compressed air above the piston 7 of the cylinder 5 flows into the expansion chamber 21 through the air passage 17 and is released to the atmosphere in the above-described stroke.
[0006]
The compressed air supplied to and discharged from the head valve chamber 19 flows into the outer periphery of the valve piston 26 through the air passage 25, flows into the expansion chamber 21 through the exhaust valve 27 of the valve piston 26, and thereafter the above-described stroke. Is released into the atmosphere.
[0007]
The compressed air supplied to and discharged from the valve piston lower chamber 20 in the trigger valve 3 flows into the expansion chamber 21 through the exhaust valve 29 of the plunger 28, and thereafter is released to the atmosphere in the above-described stroke.
[0008]
[Problems to be solved by the invention]
According to the configuration of FIG. 9, although the pressure is reduced by the pressure reducing mechanism, the exhaust pressure increases substantially in proportion to the original pressure. Further, as shown in FIG. 8, the exhaust pressure is initially high and gradually decreases with the discharge time. If the initial exhaust pressure is large, the exhaust noise also increases. When the volume of the expansion chambers 21 and 23 is increased in order to reduce the initial exhaust pressure, there is a problem that the nail driver main body becomes large. If the pressure is reduced by reducing the air passage area of the throttle passages 22 and 24 and restricting the flow rate, the exhaust time becomes long, and the continuous operation cannot be performed quickly without entering the next driving stroke. However, there is a problem that the exhaustion becomes impossible due to temperature change due to adiabatic expansion.
[0009]
An object of the present invention is to eliminate the above-described problems, to ensure quick workability without lowering the initial exhaust pressure and increasing the volume of the expansion chamber, and not to deteriorate the return performance of the piston.
[0010]
[Means for Solving the Problems]
The above object is achieved by discharging the compressed air to be discharged out of the main body after reducing the pressure with a pressure reducing valve. Further, this is achieved by providing an expansion chamber for expanding the exhausted compressed air at the front portion of the pressure reducing valve.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
1 to 8 show an embodiment of the nail driver 1 of the present invention, and the overall configuration will be described based on this embodiment.
[0012]
Compressed air from a compressor (not shown) is accumulated in the pressure accumulating chamber 4 after passing through the outer periphery of the trigger valve 3 via an air hose, an air plug, and an air passage 2 (not shown). A cylindrical cylinder 5 is provided in the main body of the nailing machine 1, and a piston 7 in which a driver blade 6 for driving a nail so as to slide up and down is integrated. A head valve 8 is provided on the upper side of the cylinder 5. When the head valve 8 is raised, the upper end of the cylinder 5 is opened and the exhaust valve 9 is closed. The pressure accumulating chamber 4 and the upper side of the piston 7 in the cylinder 5 communicate with each other. By descending, the upper end of the cylinder 5 is closed and the exhaust valve 9 is opened, so that the upper side of the piston 7 in the cylinder 5 communicates with the atmosphere via the expansion chamber 10. A return air chamber 11 for storing compressed air for returning the piston 7 to the top dead center is provided on the outer periphery of the lower end of the cylinder 5, and a check valve communicating from the cylinder 5 only in the direction of the return air chamber 11 during the reciprocating stroke of the piston 7. An air passage 13 including 12 is provided, and an air passage 14 communicating the cylinder 5 and the return air chamber 11 is provided on the outer periphery of the lower end of the cylinder 5. A piston bumper 15 is provided at the lower end of the cylinder 5 for absorbing surplus energy of the piston 7 after nail driving. The piston bumper 15 is made of a flexible material such as rubber and transforms surplus energy into heat or sound by being deformed.
[0013]
The exhaust cover 16 that houses the head valve 8 is provided with an air passage 17 that communicates the exhaust valve 9 and the handle 18. In the handle 18, an air passage 2, two expansion chambers 21 and 41, and a pressure reducing valve 40 provided between the expansion chambers 21 and 41 are provided, and a cylinder 5, a head valve chamber 19, and a valve piston lower chamber. The compressed air from 20 is expanded and depressurized. The pressure reducing valve 40 is set so that the compressed air to be discharged is below a certain pressure, and secures a flow rate so that the exhaust time is not prolonged.
[0014]
The upper end of the trigger valve 3 and the expansion chamber 21 communicate with each other, and compressed air supplied to and discharged from the head valve chamber 19 flows into the outer periphery of the valve piston 26 through the air passage 25 and passes through the exhaust valve 27 of the valve piston 26. It flows into the expansion chamber 21.
[0015]
The compressed air supplied to and discharged from the valve piston lower chamber 20 in the trigger valve 3 flows into the expansion chamber 21 through the exhaust valve 29 of the plunger 28.
[0016]
An exhaust string 30 is provided at the rear end of the handle 18, and the compressed air that has passed through the pressure reducing valve 40 passes through the expansion chamber 41 and the muffler 31, is further depressurized and rectified, and is released to the atmosphere. The exhaust string 30 is rotatably provided in the circumferential direction and can arbitrarily change the exhaust direction. In addition, a click mechanism 39 is provided at the rotating portion of the exhaust string 30 so that the exhaust direction does not change arbitrarily by the exhaust pressure.
[0017]
Next, a nail driving operation by the nail driver 1 having the above configuration will be described with reference to FIGS.
[0018]
The state where the compressed air is stored in the pressure accumulating chamber 4 is shown in FIGS. Compressed air also flows into the valve piston lower chamber 20 via the air passage 2 and the head valve 8 and the air passage 31.
[0019]
The head valve 8 shuts off the pressure accumulating chamber 4 and the cylinder 5, and the upper side of the piston 7 of the cylinder 5 communicates with the atmosphere via the expansion chamber 21 and the like. The piston 7 is located at the top dead center.
[0020]
FIG. 3 shows a state where the trigger 33 and the push lever 34 are operated and the plunger 28 is pushed up.
[0021]
The valve piston lower chamber 20 is blocked from the pressure accumulating chamber 4 and communicates with the expansion chamber 21, and the compressed air in the valve piston lower chamber 20 is discharged to the expansion chamber 21. The air is expanded and depressurized in the expansion chamber 21, passes through the pressure reducing valve 40, and further depressurized to a certain pressure.
[0022]
FIG. 4 shows a state where the valve piston 26 is lowered.
[0023]
When the valve piston lower chamber 20 becomes almost atmospheric pressure by the operation of FIG. 3, the valve piston 26 is lowered due to the pressure difference between φA and φB. When the valve piston 26 is lowered, the air passage 25 and the pressure accumulating chamber 4 are shut off, the air passage 25 and the expansion chamber 21 communicate with each other, and the compressed air in the head valve chamber 19 is discharged to the expansion chamber 21. The compressed air in the head valve chamber 19 is reduced in pressure, rectified and reduced in the same manner as the compressed air in the valve piston lower chamber 20, and released to the atmosphere.
[0024]
FIG. 5 shows a state where the head valve 8 is raised. The head valve 8 suddenly rises, the compressed air in the pressure accumulating chamber 4 flows into the cylinder 5 and pushes down the piston 7, and the driver blade 6 has a stopper 35 such as a nail or staple at the tip of the driver blade 6 to be driven, such as wood or an outer wall material. Type in. Excess energy after driving is transformed into heat or sound by deforming the piston bumper 15.
[0025]
The air below the piston 7 of the cylinder 5 is gradually compressed and flows into the return air chamber 11 through the air passage 14. When the piston 7 descends and passes through the air passage 13, the compressed air above the piston 7 of the cylinder 5 flows into the return air chamber 11.
[0026]
Next, when the trigger 33 or the push lever 34 is released, the initial state shown in FIGS. The plunger 28 is lowered by the pressure difference between φC and φD and the pressing force of the plunger spring 36. The valve piston lower chamber 20 and the expansion chamber 21 are blocked, and the valve piston lower chamber 20 and the pressure accumulation chamber 4 communicate with each other. The compressed air in the pressure accumulating chamber 4 flows into the valve piston lower chamber 20. The compressed air flowing into the valve piston lower chamber 20 causes a pressure difference of φE and φF, and the valve piston 26 rises together with the pressing force of the plunger spring 36.
[0027]
When the valve piston 26 rises, the air passage 25 and the expansion chamber 21 are blocked, and the air passage 25 and the pressure accumulating chamber 4 communicate with each other. The compressed air in the pressure accumulating chamber 4 flows into the head valve chamber 19. A pressure difference of φG and φH is generated by the compressed air flowing into the head valve chamber 19, and the head valve 8 is lowered with the pressing force of the head valve spring 37.
[0028]
When the head valve 8 is lowered, the exhaust valve 9 is opened, the compressed air above the piston 7 of the cylinder 5 is the air passage 25, and the excess compressed air after returning the piston 7 of the return air chamber 11 to the top dead center is the air passage. 38, flows into the expansion chamber 21 through the air passage 25. The piston 7 is returned to the top dead center by the compressed air in the return air chamber 11, but before the compressed air above the piston 7 of the cylinder 5 is completely discharged from the pressure reducing valve 40 to the atmosphere, the piston 7 is at the top dead center. Since the expansion chamber 21 is located between the piston 7 and the pressure reducing valve 40 even when the pressure is restored, the upper side of the piston 7 of the cylinder 5 is at a high pressure and does not stop during the return stroke of the piston 7.
[0029]
6 and 7 are enlarged views of the pressure reducing valve 40. FIG. The pressure reducing valve 40 includes a urethane ball 42 that intermittently connects the expansion chamber 21 and the expansion chamber 41, a regulator piston 43 that contacts the urethane ball 42 and controls the position thereof, and a regulator spring 44 that biases the regulator piston 43. .
[0030]
The regulator piston 43 moves in the pressure reducing valve 40 so that the force of pushing the compressed air in the expansion chamber 21 in the right direction in the figure and the force of pushing the regulator spring 44 in the left direction in the figure are balanced.
[0031]
When the pressure in the expansion chamber 21 is lower than the set exhaust pressure, the regulator piston 43 moves to the left as shown in FIG. 6, and the expansion chamber 21 and the expansion chamber 41 communicate with each other. When the pressure in the expansion chamber 21 is higher than the set exhaust pressure, the regulator piston 43 moves to the right as shown in FIG. 7 and balances at a position where the load of the regulator spring 44 is increased. If the regulator piston 43 is away from the urethane ball 42, the urethane ball 42 is urged by the urethane ball spring 45, closes the inlet of the pressure reducing valve 40, and the expansion chamber 21 and the expansion chamber 41 are shut off.
[0032]
When the compressed air in the expansion chamber 41 passes through the muffler 31 and is discharged to the atmosphere and drops to the set pressure, the regulator piston 43 pushes up the urethane ball 42 again, and the expansion chamber 21 and the expansion chamber 41 communicate with each other.
[0033]
With the above operation, the pressure reducing valve 40 does not exceed the set pressure. The relationship between the exhaust pressure and time is as shown in FIG.
[0034]
In the case of the above embodiment, the initial pressure is reduced to about 1/3 by the pressure reducing valve 40, and the exhaust gas is exhausted at the same pressure for a certain time. The exhaust end time is equivalent to that of a conventional nailer.
[0035]
【The invention's effect】
According to the present invention, the compressed air of the exhaust gas is discharged to the outside of the main body after being depressurized to a constant pressure by the pressure reducing valve, so that the rapid exhaustion continuous work can be performed without lowering the initial exhaust pressure and increasing the expansion chamber volume. Sex can be secured.
[0036]
In addition, since the expansion chamber for expanding the compressed air of the exhaust gas is provided in front of the pressure reducing valve, the above problem can be eliminated without deteriorating the return performance of the piston.
[Brief description of the drawings]
FIG. 1 is a sectional side view showing an embodiment of a nailing machine of the present invention.
FIG. 2 is a partially sectional side view showing an enlarged main part of FIG. 1;
FIG. 3 is a partial cross-sectional side view showing a state where the plunger is pushed up from FIG. 2;
4 is a partial cross-sectional side view showing a state in which the valve piston is lowered from FIG. 3;
FIG. 5 is a partial cross-sectional side view showing a state in which the piston has moved to the bottom dead center from FIG. 4;
FIG. 6 is an enlarged cross-sectional view showing a state where the regulator piston is on the left side, which is a pressure reducing valve constituting the present invention.
7 is an enlarged cross-sectional view of a pressure reducing valve showing a state where the regulator piston of FIG. 6 has moved to the right side.
FIG. 8 is a graph showing the relationship between the exhaust pressure after passing through the muffler and time.
FIG. 9 is a partial sectional side view showing an example of a nailing machine before reaching the present invention.
[Explanation of symbols]
1 is a driving machine, 3 is a trigger valve, 18 is a handle, 21 and 41 are expansion chambers, 31 is a muffler, 40 is a pressure reducing valve, 42 is a urethane ball, and 43 is a regulator piston.

Claims (2)

A housing, a handle provided in the housing, a cylinder disposed in the housing, a piston slidably disposed in the cylinder and driven by compressed air, and compressed air that has driven the piston A nailing machine for discharging to the outside of a main body , wherein the compressed air that has driven the piston is discharged to the outside of the main body through a pressure reducing valve at a pressure equal to or lower than a set pressure of the pressure reducing valve .   2. The nailing machine according to claim 1, wherein an expansion chamber for expanding the compressed air to be exhausted is provided in a front stage of the pressure reducing valve.

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