JPS6322061Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention rotates a screwdriver protruding from the tool body using a drive unit powered by compressed air, etc. The present invention relates to a screw-threading tool for screwing a screw such as a tapping screw mounted on a screw into a material to be tightened.

<Background Art and its Problems> Conventionally, screw-driving tools using an air mortar as a driving source have been widely used because they can automatically screw a tapping screw into a material to be tightened. Since the tool described above is used to drive the screw into a material to be fastened, which is made by overlapping two members such as iron plates, while drilling a screw hole therein, the rotational torque of the screwdriver is set to be large.

The air motor is designed to stop when tightening torque is applied to the driver due to the lower surface of the screw head coming into contact with the surface of the material to be tightened, and many workers think that the rotation of the driver will stop due to the air motor stopping. Completion of screwing is confirmed by stopping.

By the way, if the member on the surface side of the material to be tightened is a hard material such as a steel plate, even if the screw is screwed in until the driver stops rotating as described above, the head of the screw will not touch the surface of the material to be tightened. Screwing can be completed at the screwing reference position where the lower surface of the head comes into contact with the surface of the material to be tightened without being embedded in the screw.

However, if the member on the surface side of the material to be fastened is a soft material such as a plaster board, when the screw is screwed in until the driver stops rotating, the head of the screw will enter into the plaster board and be buried. Therefore, it is difficult to maintain the completed screwing position of the screw at the screwing reference position. Therefore, there was a risk that the vicinity of the screwed-in portion of the stone plaster board or the like would be destroyed. This is because the torque at the initial stage of screwing is greater.
This is because it becomes impossible to detect the torque when screwing is completed.

<Purpose of the invention> Therefore, the present invention was proposed in view of the conventional situation, and it is possible to set the standard for screwing a screw into a material to be tightened without being affected by the material of the material. By making it possible to keep the screw in place, it is possible to obtain a stable tightening state of various materials to be tightened, and also to prevent the destruction of the materials to be tightened. It is an object of the present invention to prevent breakage and to obtain the same effect even when applied to a hand-held tool in which tilting of the tool is expected.

<Summary of the invention> In order to achieve the above object, the screw screwing tool according to the invention has a driver drive section that applies rotational force to a screwdriver protruding from the tool body.
a trigger mechanism that supplies an ON signal to drive the same; and a trigger mechanism that is disposed between the trigger mechanism and the driver drive section, supplies an OFF signal to the driver drive section, and maintains the supply state of the OFF signal. It has a drive control section with a self-holding function, and a contact member that operates the drive control section, and the contact member is formed in a cylindrical shape, and the driver is housed inside the tube, and the driver is rotated in the axial direction of the driver. The drive control section is arranged so as to be able to slide freely along the screwdriver, and a seating surface for the material to be tightened provided at the tip of the driver is biased so as to elastically protrude from the tip of the screwdriver. It is characterized in that it is configured to operate in response to a movement signal of the contact member, which is pushed in against an elastic force when screwed to a reference position for screwing into a material to be tightened, and to self-retain.

<Example> Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a vertical sectional side view of a pneumatic screw-driving tool showing an embodiment of the present invention, and FIG. 2 is a plan view thereof. This tool includes a screwdriver 1 for screwing a tapping screw N made of a countersunk thread into a material to be tightened 100, a driver drive unit 2 for applying rotational force to this driver 1, and an ON signal for supplying an ON signal to this driver drive unit 2. The driver has a trigger valve 3 which is a trigger mechanism, a stop valve 4 which is a drive control part for supplying an OFF signal to the driver drive part 2, and a contact member 5 to actuate this stop valve 4. It becomes.

The driver drive unit 2 includes an air motor 7 disposed within a cylindrical tool body 6, and a speed reduction mechanism 8 assembled to a rotor shaft 7A of the air motor 7. The exhaust hole 7B of the air motor 7 communicates directly into a hollow grip portion 9 that is inclined at a predetermined angle and protrudes from the side of the base end 6a of the tool body 6.
Exhaust air discharged through the exhaust hole 7B is sound-reduced in the grip portion 9, further reduced in sound by a muffler 10 provided at the end 9a of the grip portion 9, and then exhausted into the atmosphere. It's becoming like that.
The output shaft 8A of the speed reduction mechanism 8 projects forward (to the left in FIG. 1) from the tip 6b of the tool body 6, and a chuck 11 is attached to the tip. A rod-shaped screwdriver 1 is mounted on the chuck 11 coaxially with the output shaft 8A of the speed reduction mechanism 8.

A valve casing 12 is provided on one side (upper part in FIG. 1) of the tool body 6, and inside this casing 12 is a trigger valve 3 that supplies an ON signal to the air motor 7, and a trigger valve 3 that supplies an ON signal to the air motor 7.
A stop valve 4 is provided to supply an OFF signal to.

As shown in FIG. 3, the trigger valve 3 includes a valve cylinder 13 and a valve piston 14 that is slidably and tightly fitted into the cylinder 13. The valve cylinder 13 is provided with a first air communication hole 15.
is connected to an air source 17 such as a compressor via an air plug 16. Further, the valve cylinder 13 has a second air communication hole 18.
The air communication hole 18 is connected to the stop valve 4 via a first air communication path 19, a switching valve 20, and a second air communication path 21.

An operating stem 22 is provided on one end (right end in FIG. 3) of the valve piston 14, and the operating stem 22 is connected to the other end (left end in FIG. 3) of the valve piston 14 and the valve cylinder 13. The valve cylinder 13 is urged to elastically protrude outward from the other end by a compression coil spring 23 for returning the valve piston, which is interposed between the valve piston and the valve piston. Tool body 6
It is in a state of protruding rearward (to the right in FIG. 1) from the base end 6b. In addition, the above valve cylinder 1
An annular chamber 24 is provided between the inner periphery of the valve piston 3 and the outer periphery of the valve piston 14. This room 24
is in communication with the air source 17 under normal conditions.

The stop valve 4 is connected to the first valve cylinder 25
A second valve cylinder 27 is attached to one end of the cylinder 25 coaxially with the cylinder 25 via a partition plate 26, and a second valve cylinder 27 is slidably and tightly fitted into the first valve cylinder 25. The valve piston 28 has a valve piston 28 and an operating stem 29 that is connected to one end of the piston 28 and is slidably and tightly fitted into the second valve cylinder 27. The first valve cylinder 25 has a first communication hole 30 that communicates with the first air communication path 21.
and a third air communication path 3 connected to the forward rotation air suction port 7a of the air motor 7.
A second air communication hole 32 that communicates with 1 is provided. Further, the second valve cylinder 27 is also provided with an air communication hole 33 that communicates with the second air communication path 21 . The operating stem 29 is operated by a compression coil spring 34 for returning the valve piston, which is interposed between the other end of the valve piston 28 (the right end in FIG. 3) and one end of the first valve cylinder 25. The second valve cylinder 27 is urged to elastically protrude outward from one end thereof, and the operating end 29a is in a state of protruding toward the tip 6b of the tool body 6. Also,
An annular chamber 35 is provided between the inner circumference of the first valve cylinder 25 and the outer circumference of the valve piston 28 . This chamber 35 is normally placed in communication with each of the air communication holes 30 and 32, and the second air communication passage 21 communicates with the third air communication passage 31 via the stop valve 4. It is becoming a state.

Also, the air suction port 7 for reverse rotation of the air motor 7
A fourth air communication passage 36 is provided between the switching valve 20 and the switching valve 20.

On the other hand, a cylindrical contact member 5 is fitted onto the outer periphery of the driver 1 so as to be slidable along the axial direction of the driver 1. The above contact member 5
A flat support block 40 is fixed to the base end 5a of the support block 40. At the tip 40a of this block 40, a tip 41a of a slide shaft 41 inserted and supported in the valve casing 12 so as to be able to reciprocate in parallel with the driver 1 is connected to an adjustment screw 4.
It is detachably assembled via 2.

A stem operating block 43 for pressing the operating stem 29 of the stop valve 4 is positioned and fixed by a screw 44 in the middle of the slide shaft 41 in the axial direction. Between the operation block 43 and the valve casing 12 is a compression coil spring 4 for returning the slide shaft, which always biases the slide shaft 41 toward the left in FIG.
5 is interposed. The elastic force of the compression coil spring 45 causes the tip 5b of the contact member 5 to
is urged to protrude further forward (to the left in FIG. 1) than the tip 1a of the driver 1, and under normal conditions, a contact member 5 is located at a position forward of the tip 1a of the driver 1. A space 46 for inserting a screw is formed surrounded by the screws.

Next, the operation of the pneumatic screw-driving tool having the above structure will be explained.

When screwing the tapping screw N into the material to be tightened 100, first operate the switching valve 20 to connect the first air communication passage 19 and the fourth air communication passage 36.
At the same time, the first air communication path 19 and the second air communication path 21 are connected to each other. Next, attach the screw N to the tip 1a of the driver 1, press the tip _N1 of the screw N against the material to be tightened 100, and move the operating stem 22 of the trigger valve 3 to the fourth
Press the button as shown in the figure. By this pressing operation of the stem 22, the chamber 24 of the trigger valve 3 is opened to the second position.
It is in a state where it communicates with the air communication hole 18 of. In this way, when the chamber 24 communicates with the second air communication hole 18, the air source 17 communicates with the first air communication path 19 via the trigger valve 3, and the air source 17 communicates with the first air communication path 19 through the trigger valve 3.
The compressed air of No. 7 is supplied to the air motor 7 through the second air communication passage 21, the stop valve 4, and the third air communication passage 31, and this air motor 7 is driven in normal rotation (rotation in the direction of screwing in the screw N). Ru.

In this way, when the air motor 7 is rotated, the driver 1 is rotationally driven via the deceleration mechanism 8,
The screw N is screwed into the material to be tightened 100 while drilling a screw hole in the material to be tightened.

As the screw N is screwed in, the seating surface 5A formed at the tip 5b of the contact member 5 changes to the tightened material surface 10 as shown in FIG.
0A and the contact member 5 is pushed in until the seating surface 5A of the contact member 5 and the upper surface _N3 of the head _N2 of the screw N are located on the same plane, the stem operation block 43 moves the stop valve 4. Push in the operating stem 29. By pushing the stem 29, the valve piston 2 of the stop valve 4
8 is pushed rightward in FIG. 6, and the communication state between the chamber 35 of the valve 4 and the third air communication hole 31 is released. In this way, when the chamber 35 and the third air communication hole 31 are cut off, the supply of compressed air to the air motor 7 is cut off, and normal rotation of the air motor 7 is stopped.

By stopping the air motor 7, the rotation of the driver 1 is reduced to the head _N2 of the screw N as shown in FIG.
It will stop at a position (screwing reference position) where the upper surface N ₃ of the bolt forms the same plane as the surface 100A of the material to be fastened 100. Therefore, even if the member 100a on the front side of the material to be fastened 100 is soft like plasterboard, the head of the screw N
This prevents N ₂ from entering the member 100a and being buried therein, preventing damage to the vicinity of the threaded portion of the screw N of the member 100a, and making it possible to obtain a stable tightening state of the member 100 to be tightened. can. Furthermore, damage to the appearance of the surface of the member 100a can also be prevented.

Note that the valve piston 28 of the stop valve 4
When the compressed air in the second air communication passage 21 is pushed in, the compressed air in the second air communication passage 21 flows through the air communication hole 33 and the second cylinder 27.
It flows into the piston lower chamber 25A of the first valve cylinder 25 through the gap S between the inner periphery and the outer periphery of the operating stem 29 and the stem insertion hole 26a of the partition plate 26. As the compressed air flows into the piston lower chamber 25A, the compressed air acts on the end surface 28A of the valve piston 28, and the pressure of the compressed air causes the valve piston 28 to self-hold at the bottom dead center position. This is the above valve piston 2
The area of the end surface 28A of 8 is one inner surface 3 of the chamber 35.
The area of the end surface 28A is larger than that of the end surface 28A.
This is because the air pressure acting on the side surface 35A is set to be greater than the sum of the air pressure acting on the one side surface 35A and the pressure of the compression coil spring 34.

The self-holding state of the valve piston 28 is released by releasing the pushing operation of the operating stem 22 of the trigger valve 3 and blocking the air source 17 and the first air communication path 19.

When the valve piston 28 of the stop valve 4 returns due to the release operation of the trigger valve 3, the compressed air stored in the piston lower chamber 25A and the annular chamber 35 of the stop valve 4 is transferred to the second air communication passage 21. , the first air communication passage 19, the second air communication hole 18 of the trigger valve 3, the piston upper chamber 13A of the valve cylinder 13 of the trigger valve 3, and the exhaust passage 37 provided at one end of the valve cylinder 13. It is released into the atmosphere and returns to the operating plane (normal state) shown in FIG.

In addition, when removing the screw N screwed into the material to be tightened 100, the switching valve 20 is operated to cut off the connection between the first air communication path 19 and the second air communication path 21, and the The first air communication path 19 and the third air communication path 36 are connected to each other. In this manner, by switching the switching valve 20, compressed air can be supplied to the reverse rotation suction port 7b of the air motor 7.
In this state, the operating stem 22 of the trigger valve 3
If you push in the air source 1 as shown in Figure 3,
7 can be supplied to the first air communication passage 19 through the trigger valve 3, and this compressed air can be supplied to the air motor 7 to drive the air motor 7 in reverse.

Furthermore, if the screw to be screwed into the material to be tightened 100 is, for example, a round screw, the reference position for screwing in the screw is a position where the lower surface of the screw head abuts the surface of the material to be tightened, and the screw head is When screwing is completed, the part protrudes from the surface of the material to be tightened. Therefore, when screwing in the screw as described above, loosen the adjustment screw 42 and tighten the contact member 5.
is moved backward along the driver 1, and adjusted so that the amount of protrusion from the tip 1a of the driver 1 is reduced. By adjusting in this way, the operation snare of the contact member 5 to the stop valve 4 is reduced, and the screwing of the screw N can be completed accurately at the screwing reference position.

In addition, in the above embodiment, the trigger valve 3
The operating stem 22 projects toward the rear of the tool body 6, but if the operating stem 22 is configured to project forward (to the right in FIG. 1) from near the base end of the grip portion 9, The stem 22 can be operated with the fingers gripping the grip portion 9, thereby improving operability.

Note that the present invention is also applicable to tools whose driving source is electricity.

<Effects of the invention> According to the screw screwing tool of the present invention, the screwdriver for rotating the screw stops when the screw reaches the screwing reference position with respect to the material to be tightened. The self-holding mechanism of the drive control unit that stops the screwdriver prevents the screwdriver from rotating when the tool is separated from the screw. It can be held in position accurately and reliably.

Therefore, according to the present invention, even if the member on the surface side of the material to be fastened is a soft material such as plasterboard, it is possible to prevent the head of the screw from entering the member. In addition, it is possible to reliably prevent the material to be fastened from being destroyed, and also to prevent the head of the screw from being damaged due to the self-holding function of the drive control section.

Further, the contact member for operating the drive control section is formed in a cylindrical shape, and the screwdriver is housed inside the cylinder, so that the seating surface at the tip of the contact member is located above the surface of the material to be tightened. It comes into contact very close to the screw. Therefore, even if the tool is tilted with respect to the material to be tightened,
The screwing reference position of the screw relative to the material to be tightened is accurately detected, and the screw is accurately held at this position in the same way as when the tool is not tilted.

[Brief explanation of the drawing]

FIG. 1 is a vertical side view showing an embodiment of the present invention;
Fig. 2 is a plan view of the same, Fig. 3 is a schematic sectional view showing the structure of the trigger valve and stop valve, Fig. 4 is a schematic sectional view of the trigger valve in the ON state, and Fig. 5 is a schematic sectional view of the screw when screwing is completed. FIG. 6 is an enlarged sectional view showing the screwed state, and FIG. 6 is a schematic sectional view of the stop valve in the ON state. 1... Screwdriver, 1a... Tip, 2
...Driver drive unit, 3...Trigger valve, 4
...Stop valve, 5...Contact member, 5A...
...Seating surface, 6...Tool body, 100...Tightened material, N...Screw.

Claims (1)

[Scope of claim for utility model registration] A screwdriver protruding from the tool body,
It has a driver drive section that is arranged inside the tool body and gives rotational force to the driver, and the drive section is turned on.
A screw-driving tool that drives a screw attached to the tip of the driver into a material to be tightened by supplying a signal, the trigger mechanism supplying an ON signal to the driver drive unit to drive it; and the driver drive unit, a drive control unit having a self-holding function that supplies an OFF signal to the driver drive unit and maintains the supply state of the OFF signal; and a drive control unit that operates the drive control unit. The contact member has a cylindrical shape, houses the driver inside the cylinder, and is slidably disposed along the axial direction of the driver,
The seating surface provided at the tip of the driver for the material to be tightened is biased so as to elastically protrude from the tip of the driver, and the drive control section is configured such that the screw is screwed into the material to be tightened to the reference position. 1. A screw-driving tool, characterized in that the tool is configured to actuate in response to a movement signal of the contact member, which is pushed in against an elastic force, and to self-hold.