JPS6240776Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention is a one-cycle operation device for a pneumatic nailer, more specifically, a one-cycle operating device for a pneumatic nailer that has a built-in pressure booster. Regarding the one-cycle actuation device that can be achieved.

Recently, pneumatic nailers with a built-in booster have been proposed and implemented. This booster has two connected compression pistons with different pressure receiving areas, and the supply air acting on the compression piston with a large pressure receiving area drives the compression piston. The booster recompresses the supplied air introduced into the side cylinder, and according to the booster described above, a strong impact force can be obtained without increasing the size of the primary pressure air supply means such as an air compressor.
However, since the half-plane booster must be built compactly for handling reasons, air needs to be consumed efficiently. For example, the primary pressure air supplied to this type of nailing machine is used to drive a booster to create high-pressure air at a predetermined pressure, and also to operate a switching valve for driving this booster. Therefore, as the consumption of boosted high-pressure air increases, the consumption of primary pressure air increases accordingly.

To explain this specifically, generally, as the driving piston moves downward, the upper cylinder volume of the piston expands, causing a pressure drop, and as a result, the air in the main chamber that stores high-pressure air is transferred to this cylinder. Replenishment will be provided within. Further, when the piston reaches the bottom dead center, the piston return air chamber is also replenished as piston return air. When the head valve closes and the piston moves back up, the high-pressure air in the cylinder above the piston is exhausted to the atmosphere, and the air that is replenished in the cylinder above the piston is thereby mixed with the air in the return chamber. The replenished air is air that is not involved in driving the piston, and exhausting it to the atmosphere can be said to be wasteful consumption. It can also be said that the air used to drive the booster to raise the pressure of the high-pressure air whose pressure has decreased due to this consumption is also wasted.

On the other hand, in the conventional pneumatic nailer, there is a mechanism that automatically opens and closes the head valve by pulling the trigger valve and performs one cycle of the driving piston, but these adopt a method of switching the head valve by switching the flow path of the trigger valve by the increase in air pressure in the return chamber after the driving piston reaches the bottom dead center. According to this method, supplementary air is supplied to the return air chamber and the pressure is increased to the point where it can switch the flow path of the head valve, and then the head valve is closed and the return of the driving piston begins, which requires time and does not contribute to saving air consumption at all.

The present invention was developed in view of the above circumstances, and it automatically closes the head valve to return the piston to the upward position before the air in the air storage chamber is replenished into the cylinder. A one-cycle actuating device for a pneumatic nailing machine is provided that advances the closing timing by adjusting the closing timing based on fluctuations in the pressure in the upper chamber of the head valve, thereby simplifying operation and reducing air consumption. The purpose is to make suggestions.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the symbol N indicates a pneumatic nailing machine with a built-in booster. This nailing machine N introduces air from an air supply means (not shown) such as an air compressor through an air inlet 10, and boosts the primary pressure air to secondary pressure by a booster A. The obtained high-pressure secondary pressure air is stored in the main chamber B and drives the driving piston of the striking part C as required, and the piston is activated by the trigger by the one-cycle actuating device D. Automatically performs one-cycle operation in response to pull operation only.

Next, the configuration of each of the above-mentioned parts of the pneumatic nailing machine N will be explained in detail.

First, in the booster A, the diametric compression piston 11
When the piston rod 12 is at the bottom dead center as shown in FIG. The air flows into the timing valve chamber 14 through the side opening 13a of the air, and is further sent to the switching valve chamber 15 through an air supply hole 16 provided in a partition wall between the switching valve chamber 15 and the switching valve chamber 15.
At this time, the switching valve 17 is biased downward by the operation of the primary pressure air in the upper chamber of the switching valve 17, thereby opening the air supply path a and closing the exhaust path b. For this reason, the switching valve chamber 1
The primary pressure air that has flowed into the cylinder 5 is supplied from the air supply port 16 to the cylinder large diameter portion 20a via the air supply and discharge port 19. However, just before the compression piston 11 descends and reaches the bottom dead center as described above, the upper protrusion 21 of the piston rod 12 engages with the inner engagement protrusion 22 of the timing valve 18. lower. At this time, the seal protrusion 32 of the timing valve 18 passes through the supply/exhaust port 23 on the upper part of the partition between the timing valve chamber 14 and the switching valve chamber 15 and communicates with the switching valve chamber upper chamber 24 and the exhaust passage 25. , the air pressure in the upper chamber 24 is released. Correspondingly, as shown in FIG. 1b, the switching valve 17 is pushed up by the air pressure within the cylinder large diameter portion 20a acting on the lower part of the switching valve 17. When the switching valve 17 rises, the air supply path a to the cylinder large-diameter portion 20a is cut off, whereas the air supply/discharge port 19 and the exhaust port 30 are connected to the cylinder large-diameter portion 20a.
Since the air exhaust path b is opened, the primary pressure acting on the large diameter portion 11a of the piston is released.
Therefore, the primary pressure on the primary side is the piston rod 1
It only acts on the tip end 12a of No. 2. on the other hand,
Inside the cylinder small diameter portion 20b, there is a 1.
Next pressure air flows in and acts on the tip of the piston small diameter portion 11b. As for the effective pressure receiving area of both tips of the piston rod 12 and piston small diameter part 11b, the piston small diameter part 11b is larger, so the pressure difference based on this area difference causes compression piston 11
returns to rise. During the upward movement of the compression piston 11, the upper end 12a of the piston rod 12 hits the stopper piston 26, and this resistance temporarily stops the upward movement of the compression piston 11.
Return will be delayed. While the cylinder is stopped, the small diameter portion 20b
A sufficient amount of primary pressure air is supplied inside. Stoppa・
The piston 26 is fitted into a cylinder 27 provided above the piston rod 12, and its stopper portion 2
6a is coaxial with the piston rod 12 and exposed to the air introduction portion 28. When the pressing force of the piston rod 12 reaches a certain level, the cylinder 2
The primary pressure air in 7 is passed through the through hole 2 of the stopper part 26a.
9 and the stopper piston 26 rises.

When the primary pressure air is sufficiently supplied into the cylinder small diameter portion 20b and approaches the original pressure, the compression piston 11 moves to the stopper piston 2, as shown in FIG. 1c.
It continues to rise again against the downward force of 6 and reaches the bottom dead center. When the compression piston 11 rises again, the lower protrusion 31 of the piston rod 12
It engages with the protrusion 22 of the valve 18 and raises the valve 18. The sealing protrusion 32 of the timing valve 18 passes through the delivery port 23 when rising, thereby opening the switching valve chamber upper chamber 24 to the timing valve chamber 14 and supplying primary pressure to the chamber 24. When air enters, the difference in effective pressure receiving area between the upper and lower ends of the switching valve 17 (the upper part is larger than the lower part)
As a result, the downward biasing force of the switching valve 17 prevails, and the valve 17 descends. Switching valve 17
When the pressure drops, the air supply path a is opened, while the exhaust path b is closed, and air supply and exhaustion are switched.

When primary pressure air flows into the cylinder large diameter section 20a, air pressure acts on the rear part of the large diameter part 11a and the front part of the small diameter part 11b of the piston 11, but the large and small diameter parts 11a and 11b are effective in receiving pressure. Due to the area difference, the pressure acting on the piston large-diameter portion 11a having a larger effective area prevails, and the compression piston 11 is pushed down and returns to the position shown in FIG. 1a again. At this time, the air within the cylinder small diameter section 20b acting on the piston small diameter section 11b is compressed and the pressure increases.
A check valve 33 is disposed at the tip opening 13b of the air inflow hole 13 of the piston rod 12, and since the compressed high-pressure secondary pressure air cannot flow backward through the inflow hole 13, the cylinder has a small diameter. The secondary pressure air is delivered to the main chamber B from the secondary pressure air outlet section 34 which is open at the bottom of the section 20b. When the compression piston 11 is descending, its protrusion 21 engages with the protrusion 22 of the timing valve 18 near the bottom dead center to lower the valve 18, and when it reaches the bottom dead center, it is again shown in FIG. As shown in FIG. 2, switching of supply and discharge of the primary pressure air by the switching valve 17 is prompted.

High-pressure secondary air supplied from the booster A having the above configuration to the main chamber B is sent to the striking section C as required, and is used as driving air for nail driving. Next, this will be briefly explained.

First, before driving, the head valve upper chamber 3
5, high pressure air in the main chamber B is introduced, and the head valve 3 is biased downward by the action of this high pressure air pressure and the compression spring 36. Further, a part of the lower end surface of the head valve 3 is exposed in the main chamber B, and an upward biasing force is generated by the action of the high pressure air in the main chamber B. It is kept stationary in the lower position due to the difference in the effective area on which high-pressure air acts. When the head valve 3 is in this position, the driving piston cylinder 4
0 is open to the atmosphere, and the drive air supply port 38 connected to the main chamber B is shut off. Further, the driving piston 39 is at the top dead center position, and the driver 41 connected thereto is retracted to an upper position.

Next, insert the nail 42 into the injection port 43 in the lower part of the main body.
After loading, the injection port 43 is brought into contact with the surface of the material to be shot, and when the trigger 45 is further pulled, this cuts off the supply of high pressure air to the upper chamber 35 of the head valve and at the same time closes the chamber. 35 to the atmosphere.

As a result, the head valve 3 loses the downward biasing force due to the air pressure that was acting on its upper surface, so that the biasing force in the main chamber B that acts on the lower surface against the pressing force of the compression spring 36 is eliminated. The cylinder 40 is moved upward by the action of high-pressure air, and the upward movement of the head valve 3 opens the driving air supply port 38 formed between the cylinder 40 and the main chamber B, and at the same time, the cylinder 40 is isolated from the atmosphere. Ru. High-pressure air in the main chamber B is instantly and in large quantities supplied into the cylinder 40 from the supply port 38, and the driving piston 39 is driven by this high-pressure air, and the driver 41 provided on the piston 39 is driven by the high-pressure air.
The nail 42 is ejected from the injection port 43 and driven into the material to be driven.

When the piston 39 descends, the cylinder 40
Atmospheric air present on the lower surface side of the piston 39 inside is removed as the piston 39 descends, and is stored in the piston return air chamber 44. Furthermore, after the piston 39 reaches the bottom dead center position, the cylinder 40
High pressure air above the piston 39 is directly introduced into the piston return air chamber 44 and stored therein through a small diameter hole 40a formed in the wall.

After driving the nail 42, the high pressure air in the main chamber B is reintroduced into the head valve upper chamber 35, and the biasing force of this high pressure air acting on the upper end surface of the head valve causes the head valve 3 to move. The cylinder 40 is lowered to close the drive air supply port 38 and open the cylinder 40 to the atmosphere. Along with this, the piston 39 receives the air pressure in the piston return air chamber 44 on its lower surface, thereby returning to the top dead center position and preparing for the next driving.
Note that due to the decrease in internal pressure in the main chamber B due to the consumption of high-pressure air during the driving operation, the above-mentioned booster A is automatically started to maintain the main chamber B at the desired pressure.

As mentioned above, one cycle of the driving piston 39 is performed by one opening/closing operation of the head valve 3, and this opening/closing of the head valve 3 is performed by the pilot valve 1 of the one-cycle operating device D. controlled. This pilot valve 1 is installed between a trigger valve 2 and a head valve 3, and when the trigger valve 2 is in a position to supply air from the main chamber B to the head valve 3 (when not in operation), It is located in a position where trigger valve 2 and head valve 3 communicate with each other, and when trigger valve 2 is operated to cut off the air supply to head valve 3 and move it to the position where it is released to the atmosphere (head valve Open) is to cut off communication between trigger valve 2 and head valve 3 and move to a position where head valve 3 and main chamber B are communicated (head valve closed). When activated, the closed head valve is opened and closed once, and the driving piston 39 is operated for one cycle.

Next, the one-cycle operating device will be explained in more detail with reference to FIGS. 2a-c.

A pilot valve 1 is fitted in a valve housing 4 which communicates with the head valve 3, trigger valve 2 and main chamber B through passages 50, 51 and 52, respectively, so as to be vertically movable. The pilot valve 1 has a cylindrical part 1b continuous below a pressure receiving head 1a, which has a first pressure receiving part 46 with a large effective pressure receiving area and a second pressure receiving part 47 with a small effective pressure receiving area on the upper and lower surfaces, respectively. The outer circumferential surface of the cylindrical part 1b is narrowed in the bottomed cylindrical body made of
A connection space 53 is formed between the inner wall of the housing 40 and the inner wall of the housing 40 . This connection space 53 is always in communication with the main chamber B. High-pressure air from the main barrier B fills the connection space 53 and is introduced into the cylindrical portion 1b through a hole 54 formed in the wall. This high pressure air is used by the pilot
It acts on the second pressure receiving part 47 of the head 1a of the valve 1, thus creating an upward biasing force. On the other hand, high-pressure air communicating with the trigger valve 2 acts on the first pressure receiving part 46 of the pilot valve 1, and therefore a downward biasing force is generated. In this way, the first part of the head part 1a of the pilot valve 1
High pressure air of approximately equal pressure acts on the pressure receiving part 46 and the second pressure receiving part 47 in opposite directions, but the first pressure receiving part 46 and the second pressure receiving part 47 act in opposite directions.
The effective pressure receiving area of the second pressure receiving part 46 is larger than the effective area of the second pressure receiving part 47, so the pilot valve 1 is biased downward due to the pressure difference based on the difference in effective area.

A contact valve stem 55 is attached to the lower part of the pilot valve 1 so as to be movable up and down, and its upper end is fitted into the cylindrical part 1b of the pilot valve 1, whereas the lower end is inserted into the cylindrical part 1b of the pilot valve 1. It protrudes below the valve housing 4, and the contact
It is in contact with the upper end of Pushyu Tsurod 56.

Before driving a nail, the sensing portion 57 of the nail tip is first brought into contact with the surface of the material to be driven. At this time, as shown in FIG. 2a, the contact push rod 56 rises together with the contact arm 58 to push the contact valve stem 55 into the valve housing 4. When the valve stem 55 moves upward, an exhaust gap is created around the valve stem 55, and the air in the upper chamber 59 of the contact valve stem 55 is exhausted, and at the same time, due to the downward biasing force applied to the pilot valve 1, Valve 1 moves down. At this time, the head 1a of the pilot valve 1 cuts off the connection between the passages 50 and 52, while the head valve 3 and the trigger valve 2 communicate with each other in order to allow the passages 50 and 51 to communicate.

Next, when the trigger 45 is pulled, the trigger valve 2 is actuated by this pulling operation. That is, the first
As shown in FIG. moves forward. At this time, an exhaust passage is formed between the valve 61 and the inner wall of the valve housing, and the head valve upper chamber 35 is opened to the atmosphere, as shown in FIG. 2b. The upper material 35 is depressurized and the head
The valve 3 moves upward and becomes open, and the air supply port 3
8 opens and the driving piston 39 descends as described above. When the pressure in the head valve upper chamber 35 is reduced, the downward biasing force on the pilot valve 1 gradually decreases, and the upward biasing force relatively increases.

Waiting until the upward biasing force on pilot valve 1 becomes greater, said valve 1
It moves up automatically as shown in Figure c. Along with this delayed operation, the head 1a of the pilot valve 1 blocks the passages 50 and 51 while blocking the passages 50 and 52.
Connect with. Therefore, communication between the head valve 3 and the trigger valve 2 is cut off, while the head valve 3 and the main chamber B are directly connected. As a result, high pressure air from the main chamber B is introduced into the head valve upper chamber 35,
It acts downward on the head valve 3 to move the valve 3 downward, so that the head valve 3 is closed, the air supply port 38 is closed, and the driving piston 39 is raised to complete one cycle. finish.

Thereafter, when the trigger 45 is first released, the trigger valve 2 is actuated and high pressure air is again introduced into the pilot valve 1 and acts on the upper end of its head, creating a downward biasing force and causing the valve 1 to move to the second position. The situation will be the same as in Figure A. Furthermore, even if the nail tip is separated from the material to be driven, the contact valve stem 55 and the pilot
Since the sealing condition of the valve cylindrical portion 1b remains unchanged, the condition shown in FIG. Furthermore, when the sensing portion 57 of the nail tip is first released from the material to be driven, the contact push rod 56 descends and the contact valve stem 55 moves downward. For this reason, the cylindrical part 1 of the pilot valve 1
The air in b flows into the contact valve stem upper chamber 5.
9 and then by releasing the trigger 45, the trigger valve 2 is actuated and the pilot
High pressure air is supplied to valve 1.
The position of is kept the same. Thereafter, by bringing the nail tip into contact with the material to be driven again, the same state as in FIG. 2a is achieved, and the next nailing operation is prepared.

As mentioned above, if the trigger 45 is pulled in the state where nail driving is prepared, the first pilot valve 1 of the one-cycle operating device is activated by this pulling operation alone.
As a delayed operation due to changes in air pressure acting on the pressure receiving part 46 and the second pressure receiving part 47, the head valve 3 is automatically changed from the open state by connecting the trigger valve 2 and the head valve 3. The driving piston 39 is brought into the closed state and one cycle operation of the driving piston 39 is performed. Operation is therefore greatly simplified.

Also, Figure 3 shows the relationship between pressure and time during the above one cycle, and P ₁
P2 indicates the air pressure between the pilot valve and the trigger valve, and _P2 indicates the air pressure between the pilot valve and the head valve. In the figure, when the trigger 45 is pulled (state A) when the head valve 3 is in the closed state, the trigger valve 2 is operated.
The air pressure at P ₁ and P ₂ decreases (state B), but as this air pressure drop progresses, the balance of the biasing force on pilot valve 1 is disrupted, causing valve 1 to rise (state C). Therefore, air is introduced into the head valve 3 from the main chamber B, _P2 rises (state A'), and at this time the head valve 3 becomes closed. In this way, the head
Since the valve 3 moves quickly from open to closed, residual pressure can be used to open the head valve 3, thereby preventing wasteful consumption of high pressure air.

As explained in detail above, according to the present invention,
When the trigger valve for starting is activated and the air supplied to the head valve is released to the atmosphere and discharged, the head valve opens and operates, supplying air from the main chamber into the driving piston cylinder and driving the driving piston. drive. However, since the air pressure acting on the first pressure receiving part of the pilot valve decreases as the air is discharged, the pressure difference between the air pressure acting on the second pressure receiving part and the air pressure acting on the second pressure receiving part decreases after a short time delay. The pilot valve is triggered.
The connection between the valve and the head valve is cut off, and the head valve is moved to a position where it communicates with the main chamber, and the head valve is closed again to cut off the air supply to the cylinder. In this way, the driving piston is operated in one cycle by the automatic opening and closing operation of the head valve based on the operation of the trigger valve, so that the operation is greatly simplified and the work efficiency is improved. In addition, since the opening and closing of the head valve is quickly switched, the supply of high-pressure air introduced into the cylinder after the piston is driven is cut off, eliminating unnecessary consumption, and the air is also used to open and close the head valve. Therefore, the consumption of air can be reduced, and stable and reliable operation of the driving piston can be obtained.

[Brief explanation of the drawing]

Figure 1a is a longitudinal sectional view of a pneumatic nailing machine including a one-cycle operating device according to the present invention, Figures b and c
2 is a partially enlarged sectional view showing the operating state of the booster of the nailing machine, FIGS. 2a, b and c are respectively operating states of the one-cycle operating device, and FIG. 3 shows the head valve and trigger valve. FIG. 3 is a relationship diagram showing the relationship between working pressure on a valve and time. Code, N: pneumatic nailer, A: booster,
B...Main chamber, C...Strike part, D...One cycle actuator, 1...Pilot valve, 2...Trigger valve, 3...Head valve, 4...Valve housing, 39... Driving piston, 46...first pressure receiving part, 47...second
pressure receiving part.

Claims (1)

[Scope of Claim for Utility Model Registration] The main chamber is located between a main chamber that stores air for driving the nail driving piston and a head valve that supplies and shuts off the air in the main chamber to the cylinder that accommodates the nail driving piston. In a pneumatic nailing machine equipped with a trigger valve that supplies or shuts off air from the head valve to release the supplied air to the atmosphere, there is a trigger valve between the trigger valve and the head valve. A pilot valve is provided that communicates and disconnects the trigger valve and the head valve, and communicates the main chamber and the head valve when the main chamber is shut off, and the pilot valve has a first valve that receives air from the trigger valve. A pressure receiving part and a second pressure receiving part receiving air from the main chamber are provided on opposite sides, and the effective pressure receiving area of the first pressure receiving part is larger than the effective pressure receiving area of the second pressure receiving part. , when the trigger valve is in the position to supply air from the main chamber to the head valve, the pilot valve
Due to the pressure difference between the air pressure applied to the first pressure receiving part of the valve and the air pressure applied to the second pressure receiving part of the valve, the pilot valve is placed in a position that communicates the trigger valve with the head valve, and the trigger valve When the air supply to the head valve is cut off and moved to the position where it is released to the atmosphere, the pilot valve A one-cycle operating device for a pneumatic nail gun, characterized in that the trigger valve is moved to a position where the trigger valve and the head valve are disconnected from each other and the head valve is communicated with the main chamber.