JPH09225850A - Screw fastening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of damaging a plus or cross shaped groove on the head of screw at the time of loosening it by providing an air supply valve in a first air supply passage for rotating an air motor with compressed air, and providing a control valve capable of being opened or closed from the outside of a housing in a second air supply passage. SOLUTION: At the time of fastening a screw 16, first a lever 8 of a changeover valve 7 is changed over to thereby enable communication between an air supply port 6 and a first air supply passage 9, and an end of a driver bit 15 is engaged with a cross-shaped groove of screw head 17. By the application of thrust through a handle 4 of a screw fastening device main body 1 gripped by an operator, an air supply valve 12 is opened in association with the rearward movement of an operation rod 22 and an air motor 2 is rotated in the normal direction by the compressed air supplied therethrough. In loosening the screw 16, the lever 8 of a changeover valve 7 is changed over to make communication between the port 6 and a second air supply passage 10, and the end of the driver bit 15 is set to the cross-shaped groove. Then, the 111 driver bit 15 is rotated in the reverse direction by pulling an operation member 14 and the screw 16 is loosened accordingly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw tightener using compressed air as a power source.

[0002]

2. Description of the Related Art Some screw tighteners using compressed air as a power source automatically start and stop a driver bit 15 by the output of an air motor 2. Above all, Fig. 5
The conventional screw tightening machine called the push start type as shown in FIG. 6 operates by allowing the driver bit 15 to move in the axial direction and moving relative to the screw tightener main body 1 when a thrust is applied to the driver bit 15. The rod 22 pushes up the air supply valve 12 so that the first air supply passage 9 for normally rotating the air motor 2 and the air supply port 6 communicate with each other, so that the system is automatically started and stopped. Therefore, the screw tightening operation is performed by engaging the tip of the driver bit 15 with the cross groove of the screw head 17 and then applying a thrust to the main body 1 to tighten the screw tightening member 19
When pressed against, the thrust is applied to the operating rod 22 via the screw 16 and the driver bit 15 to open the air supply valve 12. Then, compressed air flows in, the air motor 2 is started, the driver bit 15 rotates, and screw tightening is started. At the end of tightening the screw 16, the thrust of the handle 4 is released to close the air supply valve 12 and close the driver bit 1.
The rotation of 5 stops and the screw tightening ends. When loosening the screw 16, the switching valve 7 is switched so that the second air supply passage 10 for rotating the air motor 2 in the reverse direction is communicated with the air supply port 6, and the tip of the driver bit 15 is aligned with the cross groove of the screw head 17. By pressing the main body 1 against the screw tightening material 19, the driver bit 15 rotates in the reverse direction and the screw 16 is loosened.

FIG. 6 shows a screw tightener disclosed in Japanese Utility Model Laid-Open No. 61-75966. This screw tightening machine is a screw tightening machine shown in FIG. 5 in which a driver guide 18 which is movable in the axial direction of a driver bit 15 is screwed and attached to a nose 26 of the screw tightening machine body 1. Fastening material 19
The depth at which the screw 16 is completely tightened can be made constant. Figure 7 shows the screw tightening process with this screw tightener.
The description will be given according to (a) to (c). By applying a thrust force P to the screw tightener main body 1, a thrust force is applied to the operating rod 22 via the screw 16 and the driver bit 15 to open the air supply valve 12, whereby the air motor 2 is started and screw tightening is started. (A). As the screw tightening progresses, the screw head 17 hits the screw tightening member 19 as a stopper at the height of the screw tightening member 19 and the opening gap d between the air supply valve 12 (b). When the driver guide 18 hits the screw tightening material 19, the thrust P is not applied to the driver bit 15, and the driver bit 15 descends as the screw tightening progresses and returns to the normal position. That is, the air supply valve 12 is closed, the air motor 2 is stopped, and the screw tightening is completed (c).

[0004]

In the screw tightening machine shown in FIG. 5 as described above, the air motor 2 is started only by pressing the driver bit 15 against the screw tightening material 19 without operating the operator or the like with a finger. Therefore, there is an advantage that the work speed becomes faster, but when the driver bit 15 is loosened, if the main body 1 is pressed against the screw 16 in order to align the driver bit 15 with the cross groove of the screw head 17, a thrust force is applied to the driver bit 15. There is a case to join. In this case, the driver bit 15 has a drawback that it may rotate without being completely fitted in the cross groove of the screw head 17, and the cross groove of the screw head 17 may be crushed. In the case of the screw tightener with the handle 4, the handle 4 and the tip of the driver bit 15 are separated from each other, so that it is difficult to align the driver bit 15 with the cross groove of the screw head 17, which is likely to occur.

In the screw tightening machine shown in FIG. 6, the air motor 2 is automatically started only by pressing the main body 1 against the screw tightening material 19, and the screw guide 16 can make the screw 16 have a constant tightening depth. Therefore, there is an advantage that the finish is good, but when the screw tightening is completed, the driver guide 18 abuts on the screw tightening material 19, the driver bit 15 cannot move in the axial direction, and the air supply valve 12 cannot be pushed up. . That is, the tightened screw 16
The air motor 2 does not start even if it is attempted to loosen it. Therefore, when the screw 16 is loosened, the position of the driver guide 18 must be readjusted so that the driver bit 15 is further projected or the driver guide 18 must be removed.

The object of the present invention is to solve the above-mentioned drawbacks,
It is an object of the present invention to provide a screw tightening machine that does not crush a cross groove of a screw head when loosening a screw and can easily perform a loosening work even when a screwdriver guide is provided.

[0007]

The above object is to provide an air supply port to which compressed air from a compressor or the like is supplied, an air motor driven by the compressed air, and a driver bit which is rotationally driven by the air motor and is movable in the axial direction. And an air supply valve that is opened / closed in conjunction with the forward / backward movement of the driver bit in the axial direction, and a first supply for communicating the compressed air in the air supply port with the air motor and rotating the air motor forward and backward. In a screw tightener having an air passage and a second air supply passage, and a switching valve that switches the rotation of an air motor between forward rotation and reverse rotation, the air supply valve is provided in the first air supply passage, and the second air supply passage is provided. This is achieved by providing a control valve inside and an operator capable of operating the control valve from outside the housing. Alternatively, in the screw tightening machine, the air supply valve is provided in the first air supply passage, the control valve is provided between the air supply port and the switching valve, and the control valve capable of opening and closing the control valve is provided from outside the housing. To be achieved.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the screw fastening machine of the present invention will be described below with reference to FIG. FIG. 1 is a cross-sectional view showing an embodiment of the screw tightener of the present invention, in which an air supply port 6 is opened at a rear end of a handle 4 of a housing 3 and a compressed air source 31 such as an air compressor is connected via a hose or the like. It is connected. The compressed air flows into the air motor 2 from the air supply port 6 through the switching valve 7 in the housing 3 and the first air supply passage 9 or the second air supply passage 10 to rotate the air motor 2. An air supply valve 12 that controls communication of the passage by a driver bit 15 is provided in the first air supply passage 9, and a control valve 13 that controls communication of the passage by an operator 14 is provided in the second air supply passage 10. Has been. The switching valve 7 is a mechanism capable of switching the compressed air from the air supply port 6 to the first air supply passage 9 or the second air supply passage 10 by rotating the lever 8 to the left or right, and at the same time, When the compressed air flows in from the first air supply passage 9, the residual air communicates with the second air supply passage 10, and when the compressed air flows in from the second air supply passage 10, the residual air communicates with the exhaust air passage 20. It also plays the role of switching. The first air supply passage 9 is connected to the air motor 2 so that the air motor 2 rotates forward and the second air supply passage 10 rotates in the reverse direction. Further, the switching valve 7 may have any structure without any change from the conventional one.

The air motor 2 is driven by compressed air supplied from the air supply port 6, and the rotary shaft 24 is rotatably supported by the housing 3. The power from the rotary shaft 24 increases the torque and is transmitted to the output shaft 25 via the impact mechanism 35 and the like, and rotates the driver bit 15 provided integrally with the output shaft 25. Output shaft 25
Is provided in cooperation with the driver bit 15 so as to be able to move forward and backward in the axial direction thereof, and this movement allows the operating rod 2 to penetrate the air motor 2 and enter the air supply valve chamber 11.
The air supply valve 12 is opened and closed via 2. The air supply valve 12 opens or closes the communication path between the first air supply passage 9 and the air motor 2 based on the relative movement of the driver bit 15 with respect to the screw tightener main body 1 to supply or stop compressed air. Normally, the urethane ball or the like which is the air supply valve 12 is biased by the spring 21 and is in a closed state. When the driver rod 15 is pushed into the main body 1, the urethane ball is unsealed when the operating rod 22 hits. Then, the air motor 2 is activated. When the pushing thrust of the driver bit 15 is released, the urethane balls are closed and the air motor 2 is stopped. The control valve 13 opens and closes the communication passage between the second air supply passage 10 and the air motor 2 by operating the operator 14 from outside the handle 4. Normally, the urethane ball or the like which is the control valve 13 is in a state where the compressed air from the air supply port 6 is closed, and by pushing the operating element 14 toward the handle 4, the urethane ball seal is released and the air motor 2 is started. To do. In addition, the operator 14
When the pushing force of is released, the urethane ball is closed and the air motor 2 is stopped. The control valve 13
Since the opening and closing operation is performed by the operator 14 protruding from the outside of the handle 4, it can be easily operated with a finger while holding the handle 4 with a hand.

The operation of the screw tightener constructed as described above will be described below. In tightening the screw 16, first, the lever 8 of the switching valve 7 is switched to make the air supply port 6 and the first air supply passage 9 communicate with each other, and the driver bit 1
5 is engaged with the cross groove of the screw head 17, and the screw 16
To the predetermined screw-in part of the screw tightening material 19,
Hold the handle 4 of the screw tightener body 1 to apply thrust.
Due to this thrust, the driver bit 15, the output shaft 25, and the operating rod 22 are retracted, the air supply valve 12 is opened against the force of the spring 21, and the air motor 2 and the first air supply passage 9 are communicated and supplied. The compressed air drives the air motor 2 to rotate forward. When the air motor 2 rotates, the rotation of the air motor 2 is transmitted from the rotary shaft 24 of the air motor 2 through the impact mechanism 35 and the like to the output shaft 25.
Is transmitted to the output shaft 25, the driver bit 15 that is rotatably provided integrally with the output shaft 25 is rotated, and the screw tightening operation is started. As the screw tightening progresses, the screw head 17 becomes the screw tightening material 1.
9, when the thrust applied to the main body 1 is released, the air supply valve 12 is closed, so that the rotation of the air motor 2 and the driver bit 15 is stopped and the screw tightening is completed. As described above, the screw 16 is aligned with the driver bit 15 in the same manner as the conventional push-start type screw tightening machine.
Since the screw can be tightened just by pressing, the conventional screw tightening workability will not be impaired.

The loosening work of the screw 16 is performed by the switching valve 7
The lever 8 is switched so that the air supply port 6 and the second air supply passage 10 are communicated with each other, the tip of the driver bit 15 is aligned with the cross groove of the screw head 17, and then the operator 14 is pulled to drive the driver bit 1.
5 rotates and the screw 16 can be loosened. When aligning the tip of the driver bit 15 with the cross groove of the screw head 17,
Even if the air supply valve 12 is opened by pressing the main body 1 by mistake, the compressed air does not flow into the air supply valve 12 from the first air supply passage 9, so that the air motor 2 does not rotate. Therefore, hold the handle 4 with one hand and screwdriver bit 1
Since the air motor 2 rotates only when the operator 14 is pulled and the control valve 13 is opened after the tip of the screw 5 is securely aligned with the screw head 17, the screw head 17 is screwed without crushing the cross groove. 16 can be reliably loosened from the screw tightening material 19.

Another embodiment of the screw tightener of the present invention will be described with reference to FIG. FIG. 2 is a vertical cross-sectional view showing a screw tightening machine in which a driver guide 18 is attached to the tip of the screw tightening machine shown in FIG. 1 and used as a stopper for adjusting the tightening depth of the screw 16. The driver guide 18 is formed in a tubular shape so as to surround the driver bit 15, and has a screw portion 33 that is screwed into an adjusting screw portion 34 formed on the nose 26 at the tip of the screw tightener main body 1. The driver guide 18 has a locking ring 28 that is movable only in the axial direction with respect to the nose 26.
Is locked by a locking convex portion 29, and the locking ring 28 is always biased toward the driver guide 18 by a spring 30. This prevents the driver guide 18 from rotating due to vibration or the like. The adjustment of the driver guide 18 can be performed by moving the locking ring 28 and releasing the fitting of the locking projection 29. Driver guide 1
By adjusting 8, the amount of protrusion of the driver bit 15 from the driver guide 18 can be adjusted to obtain an arbitrary screwing depth. When loosening the screw 16 that has been once tightened by the screw tightener having the above-described structure, first, the switching valve 7 connects the air supply port 6 and the second air supply passage 10, and the tip of the driver bit 15 is made into a cross groove of the screw head 17. Engage. At this time, even if a thrust force is applied to the main body 1, since the tip of the driver guide 18 abuts against the screw tightening member 19, the thrust is not applied to the driver bit 15 and the air supply valve 12 is not opened. When the control valve 13 is opened, the air motor 2 and the air supply port 6 communicate with each other through the second air supply passage 10, the air motor 2 rotates in the reverse direction, and the driver bit 15 has the screw 16
Can be loosened from the screw tightening material 19. Therefore,
There is no need to remove the driver guide 18 or adjust the driver guide 18 so that the driver bit 15 further projects as in the conventional case, and the screw 16 can be loosened by one switching operation. Also,
Since the manipulator 14 is provided on the handle 4, the manipulator 14 can be easily operated from the state where the handle 4 is held with one hand.

Another embodiment of the screw tightener of the present invention will be described with reference to FIG. In this embodiment, as shown in the drawing, the control valve 13 provided in the second air supply passage in the embodiment of FIG.
Is provided between the air supply port 6 and the switching valve 7. In the screw tightening machine having the above-described configuration, the work cannot be started without operating the operating element 14 in both the screw tightening work and the screw loosening work. The work can be started after the driver bit 15 is surely fitted into the cross groove of the screw head 17, and the possibility of crushing the cross groove of the screw head 17 is further reduced. In addition, in the main body 1 near the operator 14, the operator 1
Locking member 50 that can be fixed in the state where 4 is pulled
Is provided, the work can be started when the air supply valve 12 is opened without operating the operating element 14 if the operating element 14 is fixed in a pulled state. It is used when you want to perform work quickly, improving workability. It is also possible to attach the driver guide 18 as shown in FIG. 2, and as in the embodiment shown in FIG. 2, remove the driver guide 18 or adjust the driver guide 18 so that the driver bit 15 further projects. It is possible to loosen the work without performing the operation.

In the above embodiment, the screws 16 are provided one by one.
4 shows a screw tightening machine to be used by hand, but as shown in FIG. 4, on a flexible connecting band 39 disclosed in U.S. Pat. No. 4,590,034 or U.S. Pat. No. 2,126,776. Hold screw 16 so-called connecting screw 3
8 sequentially, screw supply port 3 corresponding to driver bit 15
6, the feed wheel 37 is provided in the driver guide 18 which can advance and retreat in the axial direction of the driver bit 15 with respect to the main body 1, and the engaging teeth 40 on the outer periphery of the wheel 37 are provided with the side edges of the connecting band 39. The wheel 16 is engaged and the wheel 37 is intermittently rotated in response to the relative movement so that the screw 16 on the coupling band 39 is engaged.
When the present invention is applied to the screw tightening machine provided with the screw supply mechanism 36 for feeding the screw, the screw 16 can be continuously screwed into a certain depth, and the workability can be further improved. Further, also in the work of loosening the screw 16, the tip of the driver guide 18 is pressed against the screw tightening material 19 to ensure that the driver bit 15 is aligned with the screw head 17, and then the manipulator 1
It is possible to loosen the screw 16 by operating 4, and it is not necessary to adjust or remove the driver guide 18, which improves workability.

[0015]

As described above, according to the present invention, at the time of loosening a screw, even if the air supply valve is opened by pressing the main body so as to align the driver bit with the cross groove of the screw head, the air motor 2 is opened. Does not rotate, the tip of the driver bit can be completely fitted into the cross groove of the screw head. This is because the air motor was set to rotate in the reverse direction by operating the operating element.Before confirming the fitting between the tip of the driver bit and the cross groove of the screw head, operate the operating element to rotate the air motor. For example, loosening work that prevents the screw head cross groove from being crushed becomes possible. Further, in the screw tightening machine equipped with the driver guide, it is possible to easily perform the screw loosening work without the need to adjust or remove the driver guide when performing the screw loosening work.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a screw tightening machine of the present invention.

FIG. 2 is a sectional view showing another embodiment of the screw fastening machine of the present invention.

FIG. 3 is a cross-sectional view showing another embodiment of the screw fastening machine of the present invention.

FIG. 4 is a partially enlarged cross-sectional view showing another embodiment of the screw fastening machine of the present invention.

FIG. 5 is a sectional view showing an example of a conventional screw tightening machine.

FIG. 6 is a cross-sectional view showing another example of a conventional screw tightening machine.

FIG. 7 is a schematic diagram showing a screw tightening operation of the screw tightening machine shown in FIG.

[Explanation of symbols]

1 is a main body, 2 is an air motor, 6 is an air supply port, 7 is a switching valve, 9 is a first air supply passage, 10 is a second air supply passage, 12 is an air supply valve, 13 is a control valve, and 14 is an operator. , 15 are driver bits, and 18 is a driver guide.

Claims (2)

[Claims] 1. An air supply port to which compressed air from a compressor or the like is supplied, an air motor driven by compressed air, a driver bit rotatably driven by the air motor, and axially movable, and an axial direction of the driver bit. An air supply valve that is opened and closed in conjunction with forward and backward movements, a first air supply passage and a second air supply passage for communicating compressed air at an air supply port with the air motor and rotating the air motor forward and backward. A screw tightening machine having a switching valve for switching the rotation of an air motor between normal rotation and reverse rotation, wherein the air supply valve is provided in a first air supply passage, a control valve is provided in a second air supply passage, and the air supply valve is provided outside the housing A screw tightener equipped with an operator that can open and close the control valve. 2. An air supply port to which compressed air from a compressor or the like is supplied, an air motor driven by the compressed air, a driver bit rotationally driven by the air motor, and axially movable, and an axial direction of the driver bit. An air supply valve that is opened and closed in conjunction with forward and backward movements, a first air supply passage and a second air supply passage for communicating compressed air at an air supply port with the air motor and rotating the air motor forward and backward. A screw tightening machine having a switching valve for switching the rotation of an air motor between normal rotation and reverse rotation, wherein the air supply valve is provided in a first air supply passage, a control valve is provided between the air supply port and the switching valve, and the housing is external. A screw tightener equipped with an operator that can open and close the control valve more.