JPH05261676A - Compressed air screw tightening machine - Google Patents

Abstract

PURPOSE:To provide a compressed air screwing machine which is small and excellent in operability and small in the quantity of air consumption, concerning a compressed air screwing machine for screwing a screw into a material to be fastened, with compressed air as a power source. CONSTITUTION:An air actuator 1, which is rotated by compressed air, and a shifting member 14, which is rotated by the air motor 1 and also is lowered by compressed air and has, at the bottom, a drive bit 3 for driving a screw 13 and, at the top, an intake valve 10 for closing the intake passage 8 at the topside of the air motor 1, and a screw 13 is screwed into a material to be fastened by lowering only the shifting member 14, and at completion of screwing in, the intake passage 8 is closed by the intake valve 10 so that compressed air may not be supplied to the air motor wastefully, thus the quantity of compressed air consumption is lessened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressed air screw tightening machine for screwing a screw into a material to be tightened, which is designed to reduce consumption of compressed air and improve operability and durability. Is.

[0002]

2. Description of the Related Art As such a compressed air screw tightening machine, there is JP-A-1-45579 filed by the present applicant. This is to tighten a screw by lowering a moving part composed of an air motor that drives a drive bit that rotates a screw and a support member that rotatably supports the air motor by compressed air.

[0003]

The air motor is usually heavy, and the weight of the moving part occupies most of the weight of the screw tightening machine. As a result, the weight of the moving part becomes large. The reaction of the tightening machine becomes large. Further, since the outer diameter of the air motor is large, the outer diameter of the main body housing in the range in which the air motor moves up and down becomes large, and the screw tightener itself becomes large, so that the operability is extremely poor in combination with the above-mentioned recoil. . Further, as is well known, the surplus energy after the screwing of the moving portion is absorbed by the collision with the rubber damper. However, the impact generated at the time of the collision is large because the weight is large, and the impact is increased by the air motor or the air motor. Directly transmitted to bearings that support
There is also a problem that the life of the screw tightener is shortened.

Further, the supply of compressed air to the air motor is stopped by an operation valve opened and closed by a trigger,
Since the operator confirms that the tightening is completed and then returns the trigger to close the operation valve, compressed air is discharged unnecessarily from the completion of tightening until the operation valve is closed, resulting in large air consumption. There was a drawback. On the other hand, in relation to architecture,
With the increase in the amount of gypsum board used, the amount of board screws that stop the gypsum board is also increasing, and there is a strong demand for a lightweight screw tightener for tightening board screws. Conventionally, electric screw tighteners have been used, but since they are heavy, there is a strong demand for lightweight compressed air screw tighteners. However, when using a compressed air screw tightener for construction purposes, the compressed air source compressor is portable and small in size, so the conventional compressed air screw tightener cannot use much air. Therefore, there is a strong demand for the development of a compressed air screw tightener that consumes less air. Also, using a connecting screw that is connected with a connecting band for the screw to be tightened, there is a strong demand to automatically send the screw, but in a compression screw tightening machine with a screw feed device, the screw feed device also consumes compressed air, Furthermore, there is a need to reduce air consumption.

It is an object of the present invention to provide a compressed air screw tightener which eliminates the above-mentioned drawbacks of the prior art, is small in size, has good operability, and consumes little air.

[0006]

In order to achieve the above object, in the compressed air screw tightener of the present invention, it is supported in the air motor so as to be movable up and down, and is attached so as to rotate together with the air motor. A moving member having a drive bit was provided, and the moving member was rotated and lowered to screw the screw into the driven material. Also, the air inlet for supplying compressed air to the air motor is closed almost at the same time as the screwing is completed. The air inlet passage is closed by an air inlet valve provided at the upper end of the moving member,
Alternatively, the main valve, which is vertically movable above the air intake passage, may be closed by lowering it by compressed air accumulated below the moving member when tightening the screw.

[0007]

According to the compressed air screw tightener constructed as described above, since only the moving member having a small weight moves up and down, the reaction and the shock are reduced and the main body housing is also reduced. Further, when the moving member descends to the screwing completion position, the air inlet passage is closed almost at the same time as the screwing completion, wasteful consumption of compressed air is eliminated, and the consumption amount of compressed air is reduced. Be able to tighten.

[0008]

FIG. 1 shows an embodiment of the present invention.
The compressed air supplied from the compressed air intake 5 is operated by the operation valve 2
Is supplied to the upper surface of the main valve 11 and the right side of the feed piston 29 of the screw feed device 28 in the figure, and pushes the main valve 11 and the feed piston 29 downward and leftward or forward in the figure, respectively. The main valve 11 is mounted on the upper part of the housing 7 so as to be vertically movable, and is always urged downward by a spring. When the main valve 11 is at the lower end position, the air inside the main valve 11 is exhausted through the exhaust port 9. Below the main valve 11, an air motor 1 rotatably supported by a housing 7 by a pair of upper and lower bearings is provided. The air motor 1 is hollow along the axial direction, and an air intake path 8 is formed in the upper part of the air motor 1, and the air motor 1 is provided with a plurality of holes 1a provided slightly below the air intake path 8 and a ventilation path 70 provided in the housing 7. Compressed air is supplied to the wings. An air inlet valve 10 for closing the air inlet passage 8 is provided at an upper end of a moving member 14 rotatably and vertically movable in a hollow portion of the air motor 1, and a large diameter portion that comes into contact with an inner wall of the air motor 1 is a shaft. A small hole 1 provided above the central part in the direction and opening above and below the large diameter part
2 is provided, and a member forming a check valve is provided below the small hole 12. A drive bit 3 for rotating the screw 13 is integrally formed at the lower end of the moving member 14, for example. Further, the moving member 14 is, for example, spline-connected to the lower end of the air motor 1 below the moving member 14, so that the moving member 14 is simultaneously rotated by the rotation of the air motor 1. Reference numeral 6 denotes an exhaust hole provided at a position of the housing 7 opposed to the outer periphery of the air motor 1, and 30 is reciprocated left and right in the figure by a feed piston 29, for example, engaged with a feed hole portion of a connection band 33 to form a connection screw. A feed pawl having a well-known structure for supplying 32 to the injection port below the drive bit 3, and 31 is a spring for pushing the feed piston 29 to the right or rear in the drawing.

When the operation valve 2 is operated as shown in FIG. 2, the main valve 1
The compressed air acting on the upper surface of 1 is exhausted through the passage in the housing 7 and the operation valve 2, and the pressure acting on the lower surface of the main valve 11 becomes larger than the pressure acting on the upper surface of the main valve 11. To rise. As a result, compressed air enters from the air intake passage 8 and rotates the air motor 1 and the moving member 14, and at the same time rapidly lowers the moving member 14. As a result, the drive bit 3 also descends while rotating, and the screw 13 is screwed into the tightened material 20. When the drive bit 3 is lowered to the position where the screwing of the screw 13 is completed, the air intake valve 10 at the upper end of the moving member 14 closes the air intake passage 8 and the supply of compressed air to the air motor 1 is stopped.

On the other hand, the compressed air supplied to the intake passage 8 flows into the lower chamber 21 of the moving member through the small hole 12 and the check valve, and is accumulated in the lower chamber 21. Further, the compressed air in the screw feeding device 28 is also exhausted via the operation valve 2, so that the feed piston 29 and the feed pawl 30 are moved backward by the spring 31.

Next, when the operation valve 2 is released as shown in FIG. 1, compressed air is applied to the upper surface of the main valve 11 and the main valve 11 descends to open the exhaust port 9 as described above. The compressed air in the air passage 8 is exhausted. When the air above the moving member 14 is exhausted, the moving member 14 moves to the moving member lower chamber 21.
It rises due to the pressure of the compressed air accumulated in and returns to its original position.
Further, since compressed air is also supplied into the screw feed device 28, the feed piston 29 and the feed pawl 30 move forward, and the connecting screw 32 engaged with the feed pawl 30 moves forward to move the screw 13 to the above-mentioned position. Supply to the outlet.

According to the above embodiment, the lightweight moving member 14
Since only one of them is moved up and down, it is possible to reduce recoil and impact, and it is possible to downsize the main body housing 7, and as a result, it is possible to improve operability. Further, the air intake passage 8 is closed almost at the same time when the screwing of the screws 13 is completed so that the wasteful supply of compressed air is eliminated, so that the air consumption amount can be reduced, and as a result, a large number of screws 13 can be tightened. Become.

FIG. 3 shows another embodiment of the present invention.
The main valve 11 of the embodiment shown in FIGS. 1 and 2 is deleted, and when the operation valve 2 is operated, compressed air is directly supplied into the intake passage 8 and the screw feeding device 28. In contrast to the above-described embodiment, the screw feed device 28 supplies the connecting screw 32 when compressed air is exhausted and the feed piston 29 is advanced by the spring 31.

FIG. 4 shows another embodiment of the present invention.
A switching valve 22 that is opened and closed by the pressure inside the moving member lower chamber 21 is provided between the main valve 11 and the operation valve 2.

Since the piston of the switching valve 22 is in the position shown in the drawing when screwed in, when the operation valve 2 is operated, the main valve 11
Is communicated with the atmosphere through the upper chamber of the switching valve 22 and the operation valve 2, and the moving member 14 descends to start screwing in the same manner as above. When the pressure in the lower chamber 21 of the moving member increases when the screwing is almost completed, the piston of the switching valve 22 is pushed up, the upper chamber of the switching valve 22 and the operation valve 2 are shut off, and the compressed air in the housing 7 is indicated by a broken line. Since it acts on the upper surface of the main valve 11 via the passage and the switching valve 22 shown, the main valve 11 is lowered to close the intake passage 8 so that the compressed air is not wastefully consumed. The feed piston 29 of the screw feed device 28 is pushed backward by the pressure in the lower chamber 21, which is different from FIG.
It is the same as FIG. 3 in that the connecting screw 32 is fed when it is pushed forward by 1.

FIG. 5 shows still another embodiment of the present invention. Like FIG. 4, the intake valve 10 at the upper end of the moving member 14 is deleted and a predetermined time is provided between the operation valve 2 and the upper surface of the main valve 11. A time setting device 15 is provided for supplying compressed air to the upper surface of the main valve 11 to lower the main valve 11 after the passage of time. The screw feeder 28 is similar to that shown in FIG. That is, the time setting device 15 includes the first valve piston chamber 2 that opens to the chamber of the operation valve 2 through the small hole 16 with a narrowed bottom and the check valve 17.
6, the upper chamber is provided above the first valve piston chamber 26, the upper chamber is open to the air chamber in the housing 7 and the upper surface of the main valve 11, and the communication passage communicating with the first valve piston chamber 26 is the operation valve 2 The second valve piston chamber 27 opened to the chamber and the valve piston chambers 26 and 27 are moved up and down to shut off the opening of the second valve piston chamber 27 to the air chamber and the communication passage between the valve piston chambers 26 and 27. Valve piston 18
Etc.

FIG. 5 shows the standby state and the valve piston 18
Is located at the upper end position and blocks the air chamber in the housing 7 and the valve piston chambers 26, 27.
The main valve 11 is pushed by the compressed air supplied through the operation valve 2 and the second valve piston chamber 27 to close the intake passage 8.

FIG. 6 shows a tightening operation in which the operation valve 2 is operated. The compressed air on the upper surface of the main valve 11 is the second valve piston chamber 2
7. The main valve 11 is raised by being exhausted through the operation valve 2, compressed air is supplied from the air inlet 8 as in FIG. 2, and the moving member 14 is lowered while rotating to tighten the screw 13. Screw on the material 20. On the other hand, the compressed air in the first valve piston chamber 26 is gradually exhausted through the small hole 16, and the pressure thereof gradually decreases.

FIG. 7 shows the completion of screwing. When the pressure in the first valve piston chamber 26 becomes smaller than the pressure acting on the upper surface of the valve piston 18, the valve piston 18 descends and operates with the second valve piston chamber 27. The communication passage with the valve 2 is cut off, and the air chamber of the housing 7 is communicated with the upper surface of the main valve 11. Therefore, the main valve 11 descends and closes the intake passage 8.

The passage area of the small hole 16 is set to such a value that the valve piston 18 descends at the same time when the screwing of the screw 13 is completed. That is, the value is set so that the compressed air is discharged at a speed such that the pressure acting on the bottom surface of the valve piston 18 becomes smaller than the pressure acting on the upper surface of the piston 18 when the time from the start of screwing to the end of screwing has elapsed. It

In any of the above embodiments, the moving member 14 is returned to the initial position by the compressed air accumulated in the moving member lower chamber 21, but the moving member 14 rarely returns smoothly. I found out. This is because the moving member 14 does not have a large surface area like the piston of a conventionally well-known nailing machine, and there is a risk that the returning of the moving member 14 may be delayed or may not be completed. If a large surface area is provided on the moving member 14,
If the moving member 14 descends faster, the drive bit 3 may not fit well with the head of the screw 13, which may result in improper tightening. In view of this point, FIG. 8 shows that a return spring 80 is provided between the lower end of the air motor 1 and the lower flange portion of the moving member 14. Reference numeral 81 is a damper. By appropriately setting the spring constant of the spring 80, the moving member 14 can be reliably returned and the descending speed of the moving member 14 can be set to an appropriate value. In the embodiment shown in FIG. 8, the moving member lower chamber 2 is inserted through the small hole 12.
Although the moving member 14 is returned by the compressed air accumulated in 1 and the spring 80, the moving member 14 can be returned only by the spring 80, and at that time, the small hole 12 can be deleted.

In the above embodiment, the air motor 1 and the moving member 14 are connected by the spline, but the present invention is not limited to this. For example, a ball spline or rollers located on both sides of the moving member 14 may be used. It may be used, and in short, any combination may be used as long as the moving member 14 can rotate and descend as the air motor 1 rotates.

In the above embodiment, the lowering of the moving member 14 and the rotation of the air motor 1 are started at the same time, but the rotation of the air motor 1 until the bit 3 reaches the head of the screw 13 is a wasteful rotation. Air consumption increases accordingly. Therefore, for example, in the embodiment shown in FIGS. 1 to 3 and 8, the large diameter portion provided above the moving member 14 is moved from the initial position until the moving member 14 descends by a predetermined amount. If the plurality of holes 1a provided above the air motor 1 are extended upward so as to be closed, the rotation start of the air motor 1 will be delayed, and the air consumption can be further reduced by this delay.

[0024]

As described above, according to the present invention, since only the lightweight moving member is moved up and down, the reaction and the impact can be reduced, and the main body housing can be downsized. As a result, the operability is improved. You will be able to improve. Also, the air intake passage is closed almost at the same time when the screwing of the screws is completed, and the wasteful supply of compressed air is eliminated, so that it is possible to reduce the air consumption amount, and as a result, it is possible to tighten a large number of screws. Obtainable.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a compressed air screw tightener of the present invention.

FIG. 2 is a cross-sectional view showing an operating state of FIG.

FIG. 3 is a sectional view showing another embodiment of the compressed air screw tightener of the present invention.

FIG. 4 is a cross-sectional view showing another embodiment of the compressed air screw tightener of the present invention.

FIG. 5 is a sectional view showing still another embodiment of the compressed air screw tightener of the present invention.

6 is a cross-sectional view showing an operating state of FIG.

7 is a cross-sectional view showing an operating state of FIG.

FIG. 8 is a sectional view showing still another embodiment of the compressed air screw tightener of the present invention.

[Explanation of symbols]

1 is an air motor, 2 is an operation valve, 3 is a drive bit, 8
Is an air intake passage, 10 is an air intake valve, 13 is a screw, 14 is a moving member, 15 is a time setting device, 20 is a material to be tightened, 28 is a screw feeding device, and 32 is a connecting screw.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuki Omori 1060 Takeda, Katsuta City, Ibaraki Prefecture Hitachi Koki Co., Ltd.

Claims (6)

[Claims] 1. A rotatably supported body housing,
An air motor that is rotated by compressed air, and a moving member that is supported in the air motor so as to be vertically movable and that is mounted so as to rotate together with the air motor and that has a drive bit at its lower end are provided, and the moving member is rotated by the compressed air. The compressed air screw tightener is characterized by being lowered while screwing the screw into the tightening material. 2. The moving member and the rotor of the air motor are connected by a spline near the lower end of the rotor,
The compressed air screw tightener according to claim 1, wherein the moving member rotates together with the air motor. 3. A body housing is rotatably supported,
An air motor that is rotated by compressed air, a moving member that is supported in the air motor so as to be movable up and down, and is mounted so as to rotate with the air motor, and has a drive bit at its lower end, and a housing that is located above the air motor. A compressed air screw tightening machine for lowering the moving member while rotating the moving member by the compressed air to screw the screw into the tightened material. A compressed air screw tightener, characterized in that the entry air passage is closed to stop the supply of compressed air to the air motor. 4. The compressed air screw tightener according to claim 3, wherein the air intake passage is closed by an air intake valve provided at an upper end of the moving member. 5. A vertically movable main valve provided above the intake passage, and compressed air acting above the main valve during standby.
It is provided between the operation valve and the main valve upper surface so that the upper surface of the main valve is exhausted at the start of screwing, and when the screwing is completed, it is operated by the compressed air accumulated under the moving member to shut off between the main valve upper surface and the operation valve. 4. The compressed air screw tightening machine according to claim 3, further comprising a switching valve for closing the intake passage when the screwing is completed. 6. A vertically movable main valve provided above the air intake passage, and compressed air is applied to the upper surface of the main valve during standby.
A time setting device that exhausts the upper surface of the main valve at the start of screwing and causes compressed air to act on the upper surface of the main valve after a lapse of a predetermined time, and closes the intake passage by the main valve after a lapse of a predetermined time from the start of screwing The compressed air screw tightening machine according to claim 3, wherein.