JPS5820758B2 - Piston return mechanism of automatic nailer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston return mechanism in an internal combustion type automatic nailer.

Conventionally, in this type of automatic nailing machine, in order to operate the driver as a nail-driving member, a contact door arm (this contact arm normally At times, the tip is elastically biased so as to protrude toward the tip of the nose, and in this state where the tip protrudes toward the tip of the nose, the operation of the trigger valve by the trigger lever is rendered inactive) and trigger the trigger lever. The contact arm is placed in relation to the valve, and the nose is brought into contact with the surface of the material to be nailed, thereby pushing up the contact arm relative to the nose, and in this state, the trigger valve is actuated by pulling up the trigger lever. It looks like this.

Thereby, the trigger valve as a starting valve operates the drive system.

By the way, as for the method of operating the contact arm and the trigger lever, the operating procedures are different for so-called trigger driving work and for contact driving work.

In other words, during contact driving work, the trigger lever is always pulled up, and the tool body is moved up and down, that is, the tip of the nose is brought into contact with the material to be nailed, and the contact arm is moved up and down. , for driving nails.

Therefore, in this trigger driving operation, the driver is operated by switching the contact arm between ON and OFF (the trigger lever is ON at this time), and the nail is driven.

In addition, in trigger driving work, the tool body, that is, the tip of the nose, is brought into contact with the material to be nailed in advance, so the contact arm is turned on, and in this state, the trigger lever is pulled up to inject the nail and the nail driving work is started. It is something to do.

By the way, in such a trigger driving operation, when the tool bounces on the nailed material as the nail is ejected, a triple (double driving) occurs, which may cause the nail to become jammed in the nose.

Therefore, the present invention was devised in view of the actual situation in the conventional products as described above, and it eliminates the occurrence of triples in automatic nailing machines, and also solves the problem of triple occurrence in automatic nailing machines, and also solves the The purpose is to enable good exhaust and scavenging.

That is, in the case of trigger driving work, the main piston integrated with the driver does not return even when the contact arm is turned OFF and remains stationary at the bottom dead center, and the main piston returns only when the trigger lever is turned OFF. In the case of contact driving work, driving and returning can be performed only by turning the contact arm ON and OFF.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, details of the present invention will be described with reference to an embodiment shown in the drawings.

In addition, each drawing is a longitudinal sectional view of a main part showing each operating state in an automatic nailing machine to which the present invention is applied.

First, an outline of the configuration of the present invention will be explained with reference to FIG.

The state shown in FIG. 1 is a non-operating state.

In the figure, reference numeral 1 denotes a housing constituting the main body of the nail gun, and a main cylinder 2 is built inside the main body, and a main piston 3 is tightly fitted into the cylinder 2 so as to be slidable therein.

A driver 4 is integrally connected to the main piston 3 so as to protrude downward in the figure. It is inserted into the nose hole of the nose 5.

Thereby, by vertical movement of the main piston 3 in the figure, nails previously supplied into the nose 5 can be ejected one by one from a nail magazine (not shown).

Reference numeral 6 denotes a combustion chamber, and in this example, it is separately provided in the housing 1 on the upper outer periphery of the main cylinder 2 via a head valve 7.

Reference numeral 8 denotes a blowback chamber, which is spaced apart from the outer periphery of the lower part of the main cylinder 2 and communicates with the main cylinder 2 through first and second communication ports 9 and 10, respectively.

Note that a check valve 11 is disposed in the first port 9 so that only conduction from the inside of the main cylinder 2 toward the blowback chamber 8 is established.

The opening position of the first port 9 is the main piston 3.
When the main piston 3 is at the top dead center direction, it opens toward the lower chamber of the main piston, and when the main piston 3 is at the bottom dead center, it opens toward the upper chamber of the main piston.

Further, the second opening 10 normally opens toward the main piston lower chamber side, and when the main piston 3 is located at the bottom dead center (at the position indicated by the chain line 3' in FIG. 1).
The piston 3 is provided at a position where it is sealed between the seal rings 3a and 3b of the piston 3.

Reference numeral 12 denotes a contact arm, which is always urged toward the tip 5a of the nose 5 by a spring 13, so that the tip 12a of the contact arm projects further than the tip 5a of the nose.

Also, the base end 121J of the contact arm 12! l is the first
A'J! is connected to the valve stem 13A of valve A, and also connects the trigger lever 14, which will be described later. , 15 are opposed to the free ends 15a.

That is, the trigger lever 14 is connected to the housing 1 by the fulcrum pin 1.
4a, and the connecting rod 15 is pivotally supported near the operating end of the lever 14 by a fulcrum pin 15b.

The free end 15a side of the connecting rod 15 is engaged with the branch rod 12c of the contact arm 12.

Further, the pulp stem 16A of the second valve B and the pulp stem 17A of the IJ-1-J hull 7''17 are opposed to the upper surface of the connecting rod 15 in the drawing.

Further, the contact arm 12 and the trigger lever 14
An ignition means such as a piezoelectric element (not shown) is continuously disposed in the ignition means, and the ignition means is activated only when the arm 12 and the lever 14 are operated at the same time.

When only one of the arm 12 and the lever 14 is operated, the ignition means will not be activated.

The ignition means allows the air-fuel mixture in the combustion chamber 6 to be ignited by igniting the ignition means such as a spark plug (not shown) disposed so as to face the inside of the combustion chamber 6.

Note that the first valve A is a valve cylinder 13 whose upper end communicates with the combustion chamber 6, whose lower end is open to the atmosphere, and which has first and second openings 13a and 13b in the peripheral wall.
The stem 13A is slidably and tightly fitted into B,
The first opening 13a communicates with a third valve C, which will be described later, via a communication passage 31, and the second opening 13a communicates with a third valve C, which will be described later.
b is open to the atmosphere.

C is a third valve, and the cylinder 18 of the valve C has a first opening 18a at the upper end in the figure, a second opening 18b at the lower end, and third, fourth, and fifth openings 1 at the peripheral wall.
8c.

1 sci and 18e have been established.

Inside this cylinder 18, there is a first piston part 19a on the upper end side in the figure and a second piston part 19a on the lower end side.
A valve stem 19 having a diameter of 1.b is slidably and tightly fitted, and the stem 19 is normally biased by a spring 20 so as to be pushed down to the bottom dead center position in the figure.

D is a fourth valve, and its valve cylinder 21 has a first opening 21a at the upper end in the figure and a second opening 21b at the lower end, as well as openings 2 at 3° 4.5 and 6 on the peripheral wall.
1c, 21d, 21e.

21f is opened, and the valve stem 22 is slidably and tightly fitted.

The third opening 21c is connected to the third opening 21c by the communication path 28.
The upper end of the cylinder 18 of the second valve C and the side wall of the cylinder 16b of the second valve B are connected to each other.

Furthermore, the fourth opening 21d is communicated with the combustion chamber 6 through a communication passage 29.

Further, the fifth opening 21e communicates with a fifth valve E, which will be described later, and the sixth opening 21f communicates with the communication path 3.
0, the fifth opening 18e of the cylinder 18 of the third valve C and the atmosphere are opened.

The cylinder 2 is still attached to the upper end of the stem 22 in the figure.
A thin piston portion 22a, a first thick piston portion 22b, and a second thick piston portion 22c are formed corresponding to the narrow diameter portion formed on the upper end side in the figure in FIG. It is biased so that it is pushed up.

Next, E is a fifth valve, in which a valve stem 25 is slidably and tightly fitted into the valve cylinder 24.
5 is biased by a spring 26 so as to be pushed upward in the figure during normal times.

The lower end of the cylinder 24 of this valve E is opened to the atmosphere through a port 24a, and a first opening is opened in the peripheral wall.
The second opening 24b communicates with the blowback chamber 8, and the second opening 24c also communicates with the piston lower chamber side of the main cylinder 2.

Furthermore, the upper end of the cylinder 24 is connected to the fifth opening 21e of the cylinder 21 of the fourth valve D through a communication passage 27.

In the above configuration, in the state shown in FIG. 1, the trigger lever 14 has not been pulled up, and the contact arm 12 has not been pushed up either.

Therefore, in the state shown in FIG. 1, the valve stem 17A of the trigger valve 17 is at the bottom dead center, and the air chamber 60
Therefore, the head valve 7 is pushed down to the bottom dead center, and the combustion chamber 6 and the main cylinder 2 are shut off.

Also, at this time, the first, second, and third valves A, B, and C are all at the bottom dead center, and the fourth and fifth valves D and E are at the top dead center.

Therefore, the operating state will be explained when performing nail driving work from the state shown in FIG. 1.

First, in the case of trigger driving (by bringing the nose tip 5a into contact with an object (not shown) to be nailed, the contact arm 12 is pushed upward in the figure, and in this state, the trigger lever 14
(The nail driving operation is performed by pulling up the nail) will be explained in sequence with reference to FIGS. 2 to 5.

That is, when the tip 12a of the contact arm 12 is pressed against an object to be nailed (not shown), the contact arm 1
2 is pushed upward in the figure as shown in FIG.

As a result, the first valve A and each of the third to fifth valves C, D, and E are turned on.

That is, when the first valve A is turned on, the third valve C receives the internal pressure (mixture pressure) of the combustion chamber 6 and is displaced from the bottom dead center position to the top dead center position, and the displacement of the third valve C As a result, the internal pressure of the combustion chamber 6 also acts on the upper end of the fourth valve D, displacing the valve D from the top dead center position to the bottom dead center position.

Furthermore, due to the displacement of the fourth valve D, the internal pressure of the combustion chamber 6 also acts on the upper end of the fifth valve E, and the fifth valve E is also displaced from the top dead center position to the bottom dead center position. Accordingly, the fifth valve E opens the lower piston chamber in the main cylinder 2 to the atmosphere.

However, in the state shown in FIG. 2, the trigger lever 14 has not been pulled up yet, so the trigger pulp 17
and the second valve B are both in the OFF state.

Therefore, when the trigger lever 14 is pulled up from the state shown in FIG. 2 as shown in FIG. 3, the second valve B is turned on.
Therefore, the third valve C is switched OFF.

This is accomplished by applying the same pressure to the upper and lower portions of the valve stem 19 of the third valve C, and by applying the elastic force of the spring 20.

However, at this time, the pulp stem 2 of the fourth valve D
Due to the diameter difference of 2, it remains in the ON state and remains stationary.

Still, the trigger valve 17 is also turned on by the trigger lever 14, so the upper chamber 7a of the head valve 7 is opened to the atmosphere.

Then, in conjunction with the operation of the trigger lever 14, an ignition means such as a piezoelectric element (not shown) is operated in conjunction, and when the air-fuel mixture in the combustion chamber 6 is ignited by the ignition means (also not shown) such as a spark plug, the combustion pressure increases. Due to the rise, the head valve 7 is pushed up, and the combustion chamber flows into the upper chamber of the piston of the main cylinder 2, causing the main piston 3 to descend rapidly, causing an impact force to be generated on the driver 4, and preloading the engine into the nose 5. He can drive out certain nails and perform nail driving.

Note that when the main piston 3 descends inside the main cylinder 2 and passes through the first port 9, the combustion gas on the upper chamber side of the piston in the main cylinder 2 is transferred from the first port 9 to the blowback chamber. 8 and is stored in pressure.

When a single nail is driven in this way, the tool body is lifted upward in the figure by the reaction force accompanying this driving.

Then, the contact arm 12 is removed from the object to be driven.

As a result, the contact arm 12 descends downward in the figure relative to the tool body, and as a result, the first valve A is switched OFF as shown in FIG. 4, and the trigger valve 17 is also switched OFF. , again the upper chamber 7 of the head valve 7
The internal pressure of the air chamber 60 acts on the head valve 7 a.
is lowered to shut off between the combustion chamber 6 and the main cylinder 2.

At this time, the head valve 7 opens the upper chamber of the piston in the main cylinder 2 to the atmosphere.

Therefore, when the main piston 3 is at the bottom dead center position in the main cylinder 2, the upper and lower chambers reach atmospheric pressure and are in a stationary state.

Next, when the trigger lever 14 is released from the state shown in FIG. 4, the state becomes as shown in FIG. 5.

That is, by returning the trigger lever 14, the second
The fourth valve D and the fifth valve E are also turned off.

Then, the fifth valve E communicates between the blowback chamber 8 and the piston lower chamber side in the main cylinder 2, and the pressurized air stored in the chamber 8 flows into the main piston 3.
It acts on the lower side of the main piston 3 and pushes the main piston 3 toward the top dead center, thereby returning the piston and simultaneously evacuating the upper chamber of the main piston.

Next, as shown in Figs. 6 to 8, contact driving (the trigger lever is pulled up in advance, and in this state, the contact arm is activated by bringing the nose tip into contact with the object to be driven, and the nail driving operation is performed). The following describes the case of (method of carrying out).

That is, in this case, first, the trigger lever 14 is pulled up as shown in FIG.

As a result, the second valve B is turned on.

Next, the tip of the nose, ie, the contact arm 12, is pressed against an object (not shown).

Then, as shown in FIG. 7, the first valve A is also turned on, and the trigger valve 17 is also turned on.

Therefore, the upper chamber 7a of the head valve 7 is opened to the atmosphere, and at the same time, when the contact door arm 12 is operated, since the trigger lever 14 has been pulled up in advance, an ignition means such as a piezoelectric element (not shown) is activated. The air-fuel mixture in the combustion chamber 6 is ignited by an ignition means such as a spark plug (not shown), and the head valve 7 is raised due to the increase in combustion pressure, and the combustion chamber is connected to the main cylinder 2.
The inflow acts on the upper chamber side of the piston.

The state shown in FIG. 7 is the same as the state shown in FIG. 3 described above, and thereby the nail is driven in the same manner as described above.

Therefore, when the contact arm 12 is next removed from the object, the first valve A is switched OFF as shown in FIG.
The trigger valve 17 is also turned off, and the internal pressure of the air chamber 60 acts on the upper chamber 7a of the head valve 7 again, causing the head valve 7 to be lowered.

In the state shown in FIG. 8, the fifth valve E communicates between the blowback chamber 8 and the main piston lower chamber in the main cylinder 2, and transfers the internal pressure of the blowback chamber 8 to the lower chamber of the main piston 3. This will cause the piston 3 to return.

This completes one contact striking operation.

As is clear from the above configuration, in the present invention, the first valve A acts in conjunction with the contact arm, the trigger valve 17 acts in conjunction with the trigger lever, and the third valve C acts in conjunction with the contact arm 12 or the trigger lever. The fourth valve D acts to detect the order of operation of the trigger lever 14, and the fourth valve D acts to hold the detection result of the third valve C. Furthermore, the fifth valve E acts to detect the order of operation of the trigger lever 14. It is interposed between the blowback chamber 8 and the lower piston chamber of the main cylinder 2 so as to be interlocked with each other, and acts to selectively switch the lower piston chamber of the main cylinder 2 to the blowback chamber 8 or the atmosphere.

Therefore, the present invention is not limited to the above embodiments as long as it has such a configuration, and various other modifications are also possible.

In the present invention, by having the above configuration,
It is possible to easily achieve the intended purpose, such as eliminating the need for triple (double-stroke) trigger strikes and avoiding nail clogging.

[Brief explanation of drawings]

Each of the drawings is a schematic vertical cross-sectional view of a main part showing an embodiment of the present invention, and FIGS. 1 to 5 show sequentially different operating states in the order of operation in triggering work. 6 to 8 show sequentially different operating states in the same order of operation in the case of contact driving work. 2...Main cylinder, 3...Main piston, 5...Nose, 8...Blowback chamber, 12...Contact arm, 14...Trigger lever, 24a...Port, A...First valve, B...Second
valve, C...Third valve, D...
-Fourth valve, E...Fifth valve.

Claims (1)

[Claims] 1. A first valve interlocked with a contact arm that can move forward and backward in the nose axis direction with respect to the nose, a second valve interlocked with a trigger lever, and a third valve for detecting the operating state of the contact arm or trigger lever; It has a fourth valve for holding the detection result by the third valve, and a fifth valve interlocked with the fourth valve, and the first and second valves are operated by the contact arm and the trigger lever. The air inside the combustion chamber is transferred to the third
It is supplied as air for operation of the valve and signal, and
The valve receives the air supplied from the first and second valves at both ends, respectively, and is activated and deactivated, thereby deactivating and activating the fourth valve.
The fourth valve maintains the operating state of the valve, and when the fourth valve is in the operating position under the control of the third valve, the air introduced from the air inlet opening into the combustion chamber is transferred to the fifth valve. The fifth valve is electrically connected to supply the valve to the operating reservoir, and the fifth valve is configured to switch between the piston lower chamber of the main cylinder and the opening to the atmosphere or a blowback chamber. The piston return mechanism of the striking machine.