JPH11300637A - Compressed air thread fastner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the melting friction deformation of the damper fitting groove of a rotary sliding member, to prevent the deterioration of air sealing and to increase air consumption efficiency and a service life by engaging a damper with the rotary sliding member so as to prevent rotation. SOLUTION: In an compressed air thread fastener constructed in such a manner that a driver bit is attached to the driver bit fixing part of a rotary sliding member 7 supported in a rotary body rotated by an air motor so as to be moved up and down and rotated and thread fastening is operated by lowering and rotating the bit, two engaging projecting parts 77 are provided in the upper surface of a damper 76 fitted in the groove of the rotary sliding member 7. On the other hand, an engaging recessed part 78 is provided in the part of the rotary sliding member 7 opposite each of the engaging projecting parts 77. Thus, the damper 76 is fixed to the rotary sliding member 7 so as to be prevented from being rotated and slid and, when thread fastening is finished, melting friction deformation is surely prevented by avoiding rotation and sliding between the damper 76 and the rotary sliding member 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressed air screwdriver for screwing a screw into a member to be fastened. In particular, the present invention relates to an improvement of Japanese Patent Application No. 9-179789 filed earlier by the present applicant.
It is intended to improve air consumption efficiency and life.

[0002]

2. Description of the Related Art In the aforementioned application, the supply of compressed air to an air motor is stopped simultaneously with the completion of screw tightening to reduce the consumption of compressed air, and the shaft member is returned to an initial position by compressed air in a return air chamber. Proposed machine. Hereinafter, this screw tightening machine will be described with reference to FIGS.

In FIG. 5, a pressure accumulating chamber 4 communicating with a compressed air inlet 27 is provided in a body 1 forming an outer frame of the main body, and an air motor 2 having a rotor 3 rotatably supported upward. A rotatable bottomed cylindrical rotator 9 that is rotated by the rotor 3 via the planetary gear device 6 is rotatably supported. In the groove 23 of the body 1 facing the ventilation hole 51 on the substantially central side wall in the axial direction of the rotating body 9, a vertically movable cylindrical main valve 5 is provided urged upward by a spring 22. The upper and lower side surfaces of the valve 5 are sealed, and a vent hole 53 is provided in the center. Below and above the groove 23, a ventilation hole 52 and a ventilation hole 54 communicating with the operation valve 24 and the pressure accumulation chamber 4, respectively, are provided. At least one pair of concave portions 10 constituting the rotation transmitting fitting portion of the present invention is provided on the inner wall of the rotating body 9, and a pair of convex portions 8 to be inserted into the concave portions 10 is provided above, and a lower portion is provided. A rotary bit member 7 having a driver bit mounting portion on the inner side and a piston portion 13 with a seal ring mounted on the lower end portion is provided in the rotating body 9 so as to be movable in the axial direction. The upper part of the rotary slide member 7 is formed of a plastic material such as polyacetal from the viewpoint of slidability and cost. The rotary slide member 7 includes a damper 70 having an air blocking surface 11 described later and a cylinder 1 described later shown in FIGS.
5 is provided with an O-ring 12 having a diameter to be inserted and sealed. Since the damper 70 serves as an abutment surface of the rotary slide member 7 and an air seal surface as described later,
It is formed of an elastic body such as urethane rubber in terms of shock absorption and sealing properties, and is fitted into a groove (not shown) of the rotary slide member 7 only by the elastic force of the damper 70 for ease of assembly. The rotary slide member 7 is provided with an air hole 55 penetrating in the axial direction. The outer periphery of the piston portion 13 is slidable in the cylinder 15 via a seal ring. The driver bit 16 is mounted on the driver bit mounting portion of the rotary slide member 7. Above the cylinder 15, when the rotary slide member 7 descends a predetermined distance, the rotary slide member 7
The damper plate 14 is provided in contact with the air blocking surface 11 of the damper 70 on the outer periphery, and the vent hole 56 is provided below the damper plate 14. The damper plate 14 and the cylinder 15 are formed of a metal such as an aluminum material in terms of strength. The ventilation hole 56 communicates with an air inlet (not shown) of the air motor 2 via an air passage (not shown). Outflow holes 57 and inflow holes 58 are provided below the cylinder 15. An O-ring 21 constituting a one-way valve is provided on the outer periphery of the outflow hole 57. Between the lower part of the body 1 and the outer periphery of the cylinder 15, a return accumulator chamber 20 having a well-known configuration in an air nailing machine is formed. Below the body 1,
A screw feeder 19 is provided for automatically supplying the connecting screws 18 connected by a connecting band (not shown) in the magazine 25. A push lever 26 connected to the operation valve 24 is provided below the screw feed portion 19.

When the compressed air inlet 27 is connected to a compressor (not shown), the accumulator 4, the operation valve 24, and the vent 51
, Compressed air flows into the lower groove 23 of the main valve 5 through
The main valve 5 is pushed upward by the air pressure and the spring 22 so as to be pushed upward.
Is sealed at the upper end surface. That is, the space between the pressure accumulating chamber 4 and the ventilation hole 51 of the rotating body 9 is shut off so that the compressed air is not supplied to the piston 13 and the air motor 2.

When the push lever 26 and the operation valve 24 are operated, the compressed air below the main valve 5 is discharged through the ventilation hole 52 and the operation valve 24, and the compressed air pressure is applied to the outer periphery of the upper surface of the main valve 5. Therefore, the main valve 5 is pushed down against the spring 22. For this reason, compressed air flows into the rotating body 9 through the ventilation hole 54 and the ventilation hole 51 of the rotating body 9 and the like, and compressed air pressure is applied to the upper surface of the piston 13, and
At the same time, the compressed air is also supplied to the air motor 2 communicated from the ventilation hole 56 to rotate the rotor 3 of the air motor 2. The rotation of the rotor 3 is transmitted to the rotating body 9 and the rotating slide member 7 inserted into the rotating body 9 via the planetary gear device 6. As a result, the rotary slide member 7
The lower piston part 13 and the driver bit 16 rotate simultaneously while descending. Lowering of driver bit 16
By the rotation, the connection screw 18 below the connection screw is detached from the connection band, and is screwed into the workpiece 80.

As shown in FIG. 6, when the driver bit 16 is lowered to the screwing completed position, the piston 13 is moved to the piston damper 17 by the damper 7 on the outer periphery of the rotary slide member 7.
The zero air blocking surface 11 hits the damper plate 14 and stops descending. At this time, the O-ring 12 of the rotary slide member 7 seals the upper end side of the inner periphery of the cylinder 15, and the abutment of the air blocking surface 11 of the damper 70 causes the gap between the damper 70 and the damper plate 14 and between the damper 70 and the rotary slide member 7 to close. The air hole 56 is closed, and the supply of the compressed air to the air motor 2 is stopped. Therefore, the rotor 3 of the air motor 2 stops rotating,
The rotation of the planetary gear unit 6, the rotating body 9, the rotating slide member 7, the piston 13, and the driver bit 16 stops. In this state, compressed air flows from the pressure accumulation chamber 4 into the return pressure accumulation chamber 20 through the ventilation hole 54, the ventilation hole 51, the upper chamber of the rotary slide member 7, the ventilation hole 55, and the outflow hole 57.
Compressed air also flows into the lower surface side of the piston portion 13 through 8. Since the pressure receiving area of the piston portion 13 is large on the upper surface side, the piston portion 13 is stopped by being pressed against the piston damper 17.

When the operation valve 24 is returned, the compressed air flows from the pressure accumulating chamber 4 into the groove 23 below the main valve 5 through the operation valve 24 and the ventilation hole 52, and pushes the main valve 5 upward. Therefore, as described above, the space between the pressure accumulating chamber 4 and the ventilation hole 51 of the rotating body 9 is shut off, and at the same time, the ventilation hole 53 at the center of the main valve 5 communicates with the exhaust passage 59 through an air passage (not shown), thereby the piston The compressed air on the upper surface of the portion 13 is discharged outside the body 1. The compressed air in the return pressure accumulating chamber 20 is prevented from being discharged through the outlet hole 57 by the O-ring 21. As a result, the air pressure acting on the lower surface of the piston 13 returns the piston 13 and the driver bit 16 to the upper initial position. At the same time, the next screw 18 is fed onto the driver bit 16 axis by the screw feeder 19 and returns to the initial state.

[0008]

As described above, at the end of the screwing, the piston 13 stops against the piston damper 17 and the air blocking surface 11 of the damper 70 of the rotary slide member 7 stops against the damper plate 14. The supply of the compressed air to the air motor 2 is shut off, and the rotation of the screw 18 of the driver bit 16 is stopped in conjunction with the rotational load resistance.

However, since the air motor 2, the rotating body 9, the rotating slide member 7 and the like are rotating at a high speed, the rotation inertia force causes the rotation stop to be slightly delayed rather than stopped at the same time as the end. That is, the air blocking surface 11 of the damper 70 comes into a rotational sliding state while being in contact with the end surface of the damper plate 14 for a very short time, but the damper 70 abuts on the outer peripheral side and has a shape as shown in FIG. Since the slide member 7 is formed of a plastic material having good slidability, the contact frictional resistance of the abutting surface of the damper 70 becomes larger than the contact frictional resistance of the inner peripheral surface of the damper 70. It has been found that the motor stops and a rotational sliding state occurs between the inner peripheral surface of the damper 70 and the groove of the rotary slide member 7. During this time, since the rotating slide member 7 is a plastic material, the surface of the groove of the rotating slide member 7 is melted and worn and deformed due to frictional heat, and the air sealing property between the groove and the damper 70 is deteriorated. As a result, the compressed air above the damper 70 is
0, and flows into the air motor 2 from the air hole 56 through the inner peripheral side of the rotary slide member 7 at the screwing end position.
However, there is a new problem that the compressed air leaks to the outside from the exhaust path 59 communicating with the air motor 2 and is wasted, despite the fact that the pressure has reached.

An object of the present invention is to eliminate the above-mentioned disadvantages of the prior art and improve the air consumption efficiency and life of a screw tightening machine.

[0011]

The above object is achieved by making the fitting between the rotary slide member and the damper a non-rotating fit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The basic configuration and operation are almost the same as described above, and the description is omitted. As described above, two locking projections 77 are provided on the upper surface of the damper 76 fitted in the groove of the rotating slide member 7, and the engagement of the rotating slide member 7 with the portion of the rotating slide member 7 facing the locking projection 77 is performed. A locking recess 78 into which the stop projection 77 fits is provided. Rotating slide member 7
On the other hand, the damper 76 cannot rotate and slide. FIG.
When the screw tightening is completed, that is, when the rotary slide member 7 is lowered by a predetermined amount and hits, the damper 76 rotates integrally with the rotary slide member 7 for a short time. Therefore,
Slip between damper 76 and damper plate 14, damper 7
Since there is no rotational slip between the rotary slide member 6 and the rotary slide member 7, the grooves of the rotary slide member 7, which is a plastic material, do not melt and wear. Therefore, no air leakage occurs during this time.

[0013]

As described above, according to the present invention, since the fitting between the damper and the rotary slide member is a non-rotating fitting,
Melting and abrasion deformation of the damper fitting groove of the rotary slide member is eliminated, air sealing performance is not deteriorated, and air consumption efficiency and life can be improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of a main part of a rotary slide member constituting the present invention.

FIG. 2 is a perspective view showing the damper of FIG. 1;

FIG. 3 is a perspective view showing an example of a rotary slide member used in an earlier application filed by the present applicant.

FIG. 4 is a perspective view of the damper of FIG. 3;

FIG. 5 is a cross-sectional side view showing a compressed air screwdriver of the applicant's earlier application.

FIG. 6 is a sectional side view of a main part showing an operation state of FIG. 5;

[Explanation of symbols]

2 is an air motor, 7 is a rotary slide member, 9 is a rotating body,
13 is a piston part, 16 is a driver bit, 76 is a damper, 77 is a locking projection, and 78 is a locking recess.

Continued on the front page (72) Inventor Michio Wakabayashi 1060 Takeda, Hitachinaka City, Ibaraki Prefecture Inside Hitachi Koki Co., Ltd.

Claims (1)

[Claims] 1. An air motor, a cylindrical rotating body driven by the air motor and having a rotation transmitting fitting on an inner wall, supported vertically and rotatably in the rotating body, and a driver bit mounted on a lower end thereof. Part and a piston part, a rotary slide member, a damper inserted into the upper outer periphery of the rotary slide member and formed of an elastic body, and provided below the rotary body to move the piston part of the rotary slide member up and down. A cylinder that can be supported, a driver bit that is mounted on a driver bit mounting portion of the rotary slide member, and a driver bit that is provided above the cylinder and that the damper of the rotary slide member abuts the cylinder when the rotary slide member is lowered by a predetermined amount. An air passage to an air motor to be closed,
A compressed air screw tightening machine in which the screw is tightened by lowering and rotating the driver bit and the rotation of the air motor is stopped at the end of the screw tightening, and then the rotary slide member is returned to the initial position. A compressed air screw tightening machine characterized in that the fitting of (1) is a non-rotating fitting.