JP2004090146A - Compressed air thread fastener - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein when a clutch part is held on a clutch case to prevent variation in screw fastening amount and come-out due to surplus rotation, the clutch part becomes large as a whole, resulting in the disadvantage that in a thread fastener reduced in size by disposing a piston below a motor, there is not an enough space below the piston, so that the clutch part cannot be disposed. <P>SOLUTION: The clutch part 21 is reduced in size by providing a hole on the inside of one clutch body 22, providing a clutch shaft 27 rotatable and decreased in diameter at the root thereof in a hole of the other clutch body, and locking the clutch shaft 27 in the hole so that the clutch body 23 does not slip off. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
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 fastened.
[0002]
[Prior art]
By providing a clutch between the piston and the driver bit as in Japanese Patent Application Laid-Open No. Hei 6-8150 filed earlier by the present applicant, the excess rotation after the screw tightening is not transmitted to the driver bit, thus reducing the variation in screw tightening. Finish is improved.
[0003]
[Problems to be solved by the invention]
In the above screw tightening machine, the clutch was held by the clutch case, so that the entire clutch portion was large. As disclosed in Japanese Patent Application Laid-Open No. H11-28675, a piston cannot be provided in the lower portion of the motor to reduce the size of the entire screw tightening machine.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned disadvantages of the prior art and to downsize the screw tightening machine body by downsizing the clutch.
[0005]
[Means for Solving the Problems]
An object of the present invention is to provide the above-mentioned clutch unit, which comprises a first clutch body and a second clutch body having opposed meshing claws, facing each other, providing a hole in one clutch body, and being attached to the other clutch body. This is achieved by providing a clutch shaft that is rotatably movable in a hole of one clutch body and locking the clutch shaft in the hole.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
A pressure accumulating chamber 4 communicating with a compressed air inlet 35 and an operation valve 30 opened and closed by a trigger lever 33 are provided in a body 5 forming an outer frame of the main body 1, and an air motor 2 and a planetary gear device 3 located above are provided. A rotating body 6 having a bottomed cylindrical shape and rotated through the shaft is rotatably supported. The inner wall of the rotating body 6 is provided with a pair of concave portions 10 extending in the axial direction. A rotary slide member 7 having a pair of convex portions 8 above which are fitted into the concave portions 10 is provided in the rotary body 6 so as to be movable in the axial direction. The rotary slide member 7 is provided with an air blocking surface 14 and an O-ring 32 that is fitted and sealed in the cylinder 12 described later. The lower end of the shaft member 9 whose upper end is fixed to the rotary slide member 7 has a driver bit mounting portion 40 for mounting the driver bit 11, and the outer peripheral portion above the driver bit mounting portion 40 has the piston 13, the driver bit mounting portion 40 and the piston 13. A clutch portion 21 having a smaller diameter than the piston portion 13 is provided therebetween. The clutch portion 21 is composed of clutch bodies 22 and 23 having a plurality of pairs of meshing claws having a trapezoidal shape and a height of about 1.5 mm, a spring 24, a pin 25, a clutch shaft 27, and the like. The clutch shaft 27 is rotatable within a bottomed cylindrical hole provided inside the clutch body 22, has a small diameter at its root, and is locked by a pin 25. When no load is applied, the engagement claws of the clutch bodies 22 and 23 are not engaged by the spring 24 and are held rotatably. The piston 13 slides in the cylinder 12. At the upper part of the cylinder 12, there is provided a plate portion 15 which comes into contact with the air blocking surface 14 of the rotary slide member 7 when the rotary slide member 7 has descended a predetermined distance, and a ventilation hole 16 is provided below the plate portion 15. I have. The ventilation hole 16 communicates with an air inlet (not shown) of the air motor 2 via an air passage (not shown). Between the lower part of the body 5 and the outer periphery of the cylinder 12, a return air chamber 20 having a well-known configuration in an air nailing machine or the like is formed.
[0007]
Below the body 5, there is a hole through which the screw 18 and the driver bit 11 pass, and a nose portion 36 of a well-known configuration in a nailing machine is provided. The nose portion 36 is connected by a connecting band (not shown) and is loaded into the magazine 17. A screw feed section 19 for automatically supplying the connection screw 18 to the nose section 36 is provided near the nose section 36. A push lever 26 connected to the operation valve 30 is provided below the screw feed portion 19.
[0008]
The operation of the screw tightening machine of the present invention configured as described above will be described below.
The screw tightening machine of the present invention starts the drive by operating both the operation valve 30 and the push lever 26 from the state shown in FIG. 1. After the push lever 26 is pressed against the workpiece (not shown), the operation valve is operated. The screw can be tightened by pulling the operating lever 30 or by pushing the push lever 26 against the workpiece while pulling the operating valve 30. FIG. 2 shows details of the clutch unit 21 at this time.
[0009]
When the compressed air inlet 35 is connected to a compressor (not shown), the compressed air flows into the accumulator 4 and the operation valve 30. When the operating lever 30 is actuated by pressing the push lever 26 against the material to be fastened, the compressed air flows into the rotating body 6 through the operating valve 30 and the air passage (not shown), and the air pressure is applied to the upper surface of the piston portion 13 and the piston The compressed air is supplied to the air motor 2 through the ventilation port 16 while the portion 13 is pushed down, and the air motor 2 rotates. The rotation of the air motor 2 is transmitted to the rotating body 6 and the rotating slide member 7 via the planetary gear device 3. The piston body 13 below the shaft member 9 is pushed down, and the driver bit 11 pushes the head of the screw 18 off the coupling band, so that the clutch body 23 compresses the spring 24 and engages with the clutch body 22, and the screw 18 is left as it is. Screw it straight into the workpiece.
[0010]
As shown in FIG. 3, when the driver bit 11 is lowered to the screwing completed position, the air blocking surface 14 of the rotary slide member 7 hits the plate portion 15 and stops lowering. At this time, the O-ring 32 of the rotary slide member 7 seals the upper end surface of the inner wall of the cylinder 12, and the abutment of the air blocking surface 14 closes the ventilation hole 16, thereby interrupting the supply of compressed air to the air motor 2. .
[0011]
Even if the supply of compressed air to the air motor 2 is cut off, the rotating objects such as the air motor 2, the rotating body 6, and the shaft member 9 were rotating at a high speed. The compressed air remaining in the air supply passage causes the air motor 2 and the like to continue rotating. At this time, the clutch 22 continues to rotate at that position, and since the contact surface of the engagement pawl between the clutch body 23 and the clutch body 22 has an inclination and is urged by the spring 24, the clutch body 23, the driver The bit 11 follows the screw 18 and rotates down. As shown in FIG. 4, when the driver bit 11 is lowered by the height of the engagement claws of the clutch bodies 22 and 23, the engagement of the clutch bodies 22 and 23 is released, and rotation of the driver bit 11 is completely stopped, and screwing is completed. The air motor 2, the rotating body 6, the shaft member 9 and the like continue to rotate until inertia and residual air disappear. The screwing amount of the screw 18 due to the excessive rotation varies depending on the hardness of the material to be fastened, but it is about 2 mm. Therefore, if the height of the meshing claws of the clutch bodies 22 and 23 is set to 1.5 mm or less, the clutch portion 21 will always come off. Since the screw is screwed up to this, the screwing amount can be constant regardless of the hardness of the material to be fastened. At the same time, no cam-out occurs in which the driver bit tip 41 and the screw cross hole 42 are disengaged from each other, so that the driver bit tip 41 and the screw cross hole 42 are not damaged.
[0012]
When the operation valve 30 is returned, the flow of the compressed air into the rotating body 6 is shut off, and the compressed air in the return air chamber 20 returns the piston portion 13 and the driver bit 11 to their original initial positions. At the same time, the next screw 18 is fed onto the axis of the driver bit 11 by the screw feed unit 19 and returns to the initial state.
[0013]
Although the pin 25 is a cylinder, it may be a prism, a half cylinder, or a plate. In the above embodiment, the pin 25 is inserted into the clutch body 22 in the embedding direction. However, the pin 25 may protrude from the outer periphery of the clutch body 22 to the center axis of the clutch shaft 27.
[0014]
【The invention's effect】
As described above, according to the present invention, the clutch portion is provided with a hole inside one clutch body, and the other is provided with a clutch shaft that can rotate and move within the hole, and the clutch shaft is inserted into the hole so that the clutch does not fall off. With the configuration in which the pin is engaged, the size of the clutch unit can be reduced, and the size of the entire screw tightening machine can also be reduced. By providing the clutch portion, it is possible to suppress the variation in the amount of screw tightening, and it is also possible to prevent cam-out caused by excessive rotation.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional side view showing an embodiment of the screw tightening machine of the present invention.
2 is a perspective exploded sectional view of a main part of FIG. 1; FIG. 3 is a partial sectional side view showing an operation state of FIG. 1;
FIG. 4 is a partial cross-sectional side view showing the operation state of FIG. 1;
[Explanation of symbols]
1 is a main body, 9 is a shaft member, 11 is a driver bit, 13 is a piston part, 18 is a screw, 21 is a clutch part, 22 and 23 are clutch bodies, 25 is a pin, and 27 is a clutch shaft.

Claims (4)

A compression device including a driver bit that is given rotation and axial movement by an air motor and an air piston, and a clutch unit that is provided between the driver bit and the air piston and that does not transmit excess rotation to the driver bit after screwing is completed. An air screwdriver,
The clutch portion includes a first clutch body and a second clutch body having opposed meshing claws, facing each other, a hole is provided in one clutch body, and a clutch shaft attached to the other clutch body is provided. A compressed air screw tightening machine characterized in that it is rotatably provided in a hole of one clutch body and a clutch shaft is locked in the hole. The compressed air screwdriver according to claim 1, wherein the clutch shaft is locked by a pin. 3. The compressed air screw tightening machine according to claim 1, wherein an outer diameter of the clutch portion is smaller than a piston diameter. 2. The compressed air screw tightening machine according to claim 1, wherein the height of the clutch engagement pawl of the clutch portion is 1.5 mm or less.

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