JPH0236710Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention is a nailing machine, in particular, a cylinder housing a striking piston integrally coupled with a driver member is configured to be movable up and down, and a drive member is driven at the upper and lower ends of the movable cylinder. The present invention relates to a nailing machine in which a switching valve for switching and controlling air supply and discharge is switched at the top dead center position of the striking piston and at the upper movement position of the movable cylinder.

(Prior art) In general, pneumatic impact tools reciprocate the impact piston by switching drive air to impact the means to be driven, such as a nail, loaded in front of it. Kosho 50-
As shown in Publication No. 14220, there is a method in which the means to be driven is driven in with a single blow, and a
As shown in Japanese Patent No. 12913, there is a method in which the striking piston is vibrated to drive the driven means little by little by multiple strikes. In the former, the driving air is manually switched at the bottom dead center of the stroke, and in the latter, the driving air is switched depending on the stroke position of the striking piston.

Incidentally, a tool that automatically supplies and continuously drives long nails, etc. requires a long nose portion to accommodate the nails, etc., and therefore a striking piston with a long striking stroke is used. However, when driving with a striking tool configured to switch the drive air at the bottom dead center of the stroke of the striking piston, as in the one-time driving method described above, the driving resistance of long nails increases accordingly, so it is possible to drive only partway through the nail. Sometimes there isn't. At this time, the driving air cannot be switched, so the striking piston stops and becomes unusable. Furthermore, if the striking piston stops midway through its stroke, there is a risk that the tool will bounce back due to the reaction.

In addition, the vibration impact method switches the valve depending on the position of the impact piston near the bottom dead center of the impact piston, so the impact stroke is structurally small, so it is not suitable for devices with long driving means.

(Technical problem of the invention) The present invention solves the above-mentioned drawbacks, and is capable of automatically switching the driving air to the percussion piston when the percussion piston stops, regardless of the stroke position of the percussion piston. The technical problem is to provide a nail gun that is effective when driving a striking piston with a long stroke for driving nails.

(Means for Solving the Problems) In order to solve the above problems, a nailing machine according to the present invention includes a movable cylinder provided in a housing so as to be movable up and down and biased downward by a spring; A striking piston slidably housed in a cylinder, a driver member integrally connected to the striking piston, and supply/exhaust ports provided at the upper and lower ends of the movable cylinder are connected to a drive air supply source and the atmosphere. a switching valve connected alternately and selectively; two independent operating chambers for the switching operation of the switching valve by driving air; communicating with one operating chamber of the switching valve and opening an exhaust hole by upward movement of the movable cylinder; A port that cuts off the connection with the valve and starts supplying driving air into the working chamber communicates with the other working chamber of the switching valve, and cooperates with the piston that has returned to the top dead center position to start supplying driving air into the working chamber. and a port that communicates with an opening formed in the side wall of the movable cylinder, and a port that is provided between each of the operating chambers and the drive air supply source and that is connected to the supply/exhaust port of the movable cylinder. The invention is characterized in that it includes two pilot valves that are actuated alternately by the introduced driving air to selectively connect each of the working chambers to the driving air supply source and the atmosphere through the port.

(Operations and effects of the invention) Since the nailing machine according to the invention is configured as described above, when the striking piston is driven downward by the driving air, the driving resistance of the nail is large. When the drive piston stops midway through its stroke, the drive air acts in reaction to push the movable cylinder upward against the spring force, causing the movable cylinder to move upward. As a result, supply and exhaustion of drive air by the switching valve is switched, and the drive air is exhausted from the upper end of the movable cylinder and supplied to the lower end, so that the striking piston is shifted to the return stroke and driven upward. At the same time, since the driving air that has moved the movable cylinder upward is also supplied and discharged, the movable cylinder is moved downward again by the spring force. After that, when the striking piston reaches the top dead center position, the switching valve switches and operates again.
The striking piston is driven downward by driving air. Thereafter, the above operation is repeated, and when the hammering piston finally reaches the bottom dead center of the striking stroke and nail driving is completed, the movable cylinder is pressed downward by the striking piston, so it will not move upward. Therefore, the switching valve also becomes inoperable.
The striking piston stops at bottom dead center.

As described above, according to the present invention, the driving air for the striking piston can be automatically switched by stopping the striking piston, regardless of the stroke position of the striking piston. This is very effective when driving a striking piston with a long stroke.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In the figure, the symbol A indicates a nailing machine. This nailing machine A includes a movable cylinder 3 provided in a housing 1 that is movable up and down and biased downward by a spring 2, and a striking cylinder 3 that is slidably housed in the movable cylinder 3. A piston 4, a driver member 5 integrally coupled to the striking piston 4, and an upper and lower cylinder port 6, 7 connected to supply/exhaust ports 40, 41 at the upper and lower ends of the cylinder 3, respectively. A switching valve 8 is provided at the upper and lower ends of the striking piston 4 to selectively communicate a driving air supply source (not shown) such as an air compressor with the atmosphere. The switching valve 8 is composed of upper and lower pilot valves 9, 10 which are switched and actuated in the upper movement position of 3, and a trigger valve 11 which controls opening and closing of the supply of driving air from the driving air supply source to the switching valve 8.
At the tip of the housing 1 is the driver member 5.
and the nail driving passage 1.
2 and a nose portion 13 is formed.

The switching valve 8 constantly communicates with a supply port 14 leading to a drive air supply source, and also connects to the supply/exhaust ports 40 provided at the upper and lower ends of the movable cylinder 3 via the upper and lower cylinder ports 6 and 7, respectively.
Connected to 41. Furthermore, operating chambers 42 and 43 are provided at the upper and lower ends of the switching valve 8, respectively, and these operating chambers 42 and 43 are connected to the upper and lower pilot valves 9 and 10 through upper and lower switching ports 15 and 16, respectively. There is. Further, the switching valve has a valve stem 22 slidably housed in a valve housing 19 having exhaust ports 17 and 18 at the upper and lower portions, respectively, and having seal portions 20 and 21 between the upper and lower portions. Each seal 20, 21 is such that when the valve stem 22 moves up and down in the valve housing 19, the upper and lower cylinder ports 6, 7 are selectively switched to the supply port 14 or the exhaust port 17 or 18, and one cylinder port 6 or 7 communicates with the supply port 14, the other cylinder port 7 or 6 is configured to communicate with the exhaust port 18 or 17.

The upper and lower pilot valves 9 and 10 are respectively connected to the supply port 14 and the upper and lower cylinder ports 6 and 7.
A small diameter portion 24, a large diameter portion 25, and a seal portion 26 are located in a valve housing 28 that communicates with the lower and upper switching ports 16 and 15 and has an exhaust port 27.
The valve stem 30 is slidably housed, and when each seal portion 26 moves up and down,
Lower and upper switching ports 16 and 15 are supply port 1
4 or the exhaust port 27.

Upper and lower opening/closing ports 31 and 32 are branched from the lower and upper switching ports 16 and 15, respectively. Note that the upper opening/closing port 31 is formed so as to be able to communicate with the inside of the movable cylinder 3 through an opening 31a formed in the upper part of the movable cylinder 3. These upper and lower opening/closing ports 31 and 32 are connected to the movable cylinder 3.
When the movable cylinder 3 is biased to the lower position by the spring 2, it is opened to the upper part of the movable cylinder 3 and the exhaust hole 23, and when the movable cylinder 3 rises against the spring 2, the cylinder wall opens. The upper opening/closing port 31 is also in the closed state when the striking piston 4 is located at the top dead center.

Next, the operating mode of the nailing machine A having the above configuration will be sequentially explained.

(1) Starting the striking piston (see Fig. 1) First, the nail N is loaded into the nose portion 13. In this state, the switching valve 8 is at the top dead center. Therefore, when the trigger valve 11 is operated to open the supply port 14 to the driving air supply source, the upper seal part 20 of the switching valve 8 connects the supply port 14 to the upper cylinder port 6, and the lower seal part 21 connects the supply port 14 to the upper cylinder port 6. 14, drive air is supplied from the upper cylinder port 6 to the upper end of the movable cylinder 3. The lower seal portion 21 connects the lower cylinder port 7 communicating with the lower end of the cylinder 3 to the exhaust port 18 . Therefore, the striking piston 4 is actuated by the pressure of the driving air supplied to the upper end of the cylinder 3, and the driver member 5 strikes the nail N.

At this time, the driving air from the supply port 14 acts on the small diameter portions 24, 24 of the valve stems 30, 30 of the upper and lower pilot valves 9, 10.
However, since the driving air also acts on the large diameter portion 25 of the upper pilot valve 9, the valve stem 30 of the upper pilot valve 9 slides downward due to the difference in pressure receiving area between the two. By the downward movement of the striking piston 4, the driving air in the movable cylinder 3 is transferred from the upper opening/closing port 31 to the lower switching port 1.
However, as the valve stem 30 slides downward, the seal portion 26 is positioned to open the lower switching port 16 to the exhaust port 27, so the driving air is exposed to the atmosphere. On the other hand,
Since the large diameter chamber 25 of the lower pilot valve 10 is open to the atmosphere through the exhaust port 18 along with the lower cylinder port 7, the valve stem 30 moves downward due to the pressure of the driving air from the supply port 14, which causes the seal to close. portion 26 is the supply port 14
Move the switch to the position where it is connected to the upper switching port 15. However, since the opening/closing port 32 branching from the upper switching port 15 communicates with the exhaust hole 23, the driving air is also exposed to the atmosphere.

(2) Midway stop of the striking piston (see Figure 2) When the striking piston 4 strikes the nail N, the nail N is driven into the material a little, but the driving resistance is greater than the striking force, so the striking piston 4 It stops midway through its range of motion. The air pressure of the driving air acts on the upper bottom surface of the movable cylinder 3, and the cylinder 3 rises against the spring force of the compression spring 2. Movable cylinder 3
When the upper and lower opening/closing ports 31 and 32 are raised, the upper and lower opening/closing ports 31 and 32 are closed. When the lower opening/closing port 32 is closed, the supply port 14 is opened through the lower pilot valve 10.
The air supplied to the upper switching port 15 begins to act on the upper end of the valve stem 22 of the switching valve 8. On the other hand, even if the upper opening/closing port 31 is closed, the lower switching port 16 remains open to the atmosphere through the exhaust port 27.

(3) Switching of driving air (see Fig. 3) The valve stem 22 of the switching valve 8 moves downward by the supply of driving air from the upper switching port 15. For this reason, the upper seal portion 20 is closed to the supply port 14 and the upper cylinder port 6
is communicated with the exhaust port 17. At the same time, the lower seal 21 opens the supply port 14 to the lower cylinder port 7. As a result, the driving air from the supply port 14 is switched and supplied to the lower end of the movable cylinder 3 from the lower cylinder port 6, and the upper end of the movable cylinder 3 is opened to the atmosphere from the exhaust port 17. Therefore, the striking piston 4 begins to rise, and at the same time, the movable cylinder 3 returns to the lower position by the spring force of the compression spring 2.

As the movable cylinder 3 returns downward, the upper opening/closing port 31 becomes open, and the air that was acting on the lower end of the valve stem 22 of the switching valve 8 passes from the lower switching port 16 to the movable cylinder 3 and the upper cylinder port 6 to the exhaust port. It is exhausted from 17.

Also, since the air pressure acting on the large diameter portion 25 of the upper pilot valve 9 is released, the valve stem 30 slides upward due to the pressure of the driving air acting on the small diameter portion 24, and the seal portion 26 closes. Supply port 14 is opened to lower switching port 16. However, since the lower switching port 16 is open to the atmosphere through the port 31, the switching valve 8 is not operated at this stage.

(4) Return of the striking piston to the upward position (see Fig. 4) When the striking piston 4 returns to the top dead center position, the upper opening/closing port 31 is closed, so the supply port 14 is connected to the lower switching port 16 through the upper pilot valve 9. The driving air supplied to the switching valve 8 is supplied to the lower end of the switching valve 8. On the other hand, when driving air is introduced into the lower cylinder port 7, a part of it acts on the large diameter part 25 of the valve stem 30 of the lower pilot valve 10, and due to the difference in pressure receiving area with the small diameter part 24, this air is Because it operates upwards,
Communication between the upper switching port 15 and the supply port 14 is closed.

(5) Re-switching the driving air (see Figure 5) As mentioned above, the air pressure on the upper and lower ends of the valve stem 22 of the switching valve 8 is reversed when the striking piston 4 returns to the top dead center, so the switching valve 8 slides upward again. However, as a result, the driving air is switched again and the driving air is supplied to the upper end of the movable cylinder 3, and the lower end of the cylinder 3 is opened to the atmosphere, so that the striking piston 4
is driven downwards and strikes the nail.

(6) The striking piston reaches the bottom dead center (see Figure 6).Then, repeat the operations (1) to (5) in the same way. and,
The striking piston 4 reciprocates several times to repeatedly strike the nail N, and finally the nail N is completely driven into the material, the striking piston 4 reaches the bottom dead center, and the movable cylinder 3
When it hits the bumper 35, the movable cylinder 3 is held down by the striking piston 4 and cannot move upward. Therefore, since the opening and closing ports 31 and 32 cannot be switched, the operation of the upper and lower pilot valves 9 and 10 is fixed, and the switching valve 8 is not switched, so the striking piston 4 stops at the bottom dead center. This will complete the nail driving process.

As described above, according to the nailer A, the driving air for the percussion piston 4 can be automatically switched by stopping the percussion piston 4, regardless of the stroke position of the percussion piston 4.
This is particularly effective when driving a striking piston 4 with a long stroke for driving long nails.

[Brief explanation of drawings]

1, 2, 3, 4, 5, and 6 are explanatory diagrams of the operating state of the nailing machine according to the present invention. Symbol A..., 1... Housing, 3... Movable cylinder, 4... Impact piston, 5... Driver member, 6... Upper cylinder port, 7... Lower cylinder port, 8... Switching valve, 9... ...Upper pilot valve, 10...Lower pilot valve, 14...Supply port, 15...Upper switching port, 16...Lower switching port, 17, 18...
...Exhaust port, 20, 21, 26...Seal part,
23...exhaust hole, 22,30...valve stem,
31, 32... Opening/closing port.

Claims (1)

[Scope of Claim for Utility Model Registration] A movable cylinder provided in a housing so as to be movable up and down and biased downward by a spring; a striking piston slidably housed within the movable cylinder; and the striking piston. a driver member integrally coupled to the movable cylinder; a switching valve that alternately and selectively connects supply and exhaust ports provided at the upper and lower ends of the movable cylinder to a driving air supply source and the atmosphere; and switching of the switching valve by the driving air. Two independent working chambers for operation communicate with one working chamber of the switching valve, and the connection with the exhaust hole is cut off by upward movement of the movable cylinder to start supplying driving air into the working chamber. a port that communicates with the other actuating chamber of the switching valve;
and a port that cooperates with the piston that has returned to the top dead center position to start supplying driving air into the working chamber and communicates with an opening formed in the side wall of the movable cylinder; and is alternately actuated by driving air introduced into the supply/exhaust port of the movable cylinder to selectively connect each of the working chambers to the driving air supply source and the atmosphere through the port. A nailing machine characterized by being equipped with two pilot valves.