JPH042378B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an automatic screw fastening device, particularly an automatic screw suitable for use in screws that perform screw fastening while adding a driving effect, such as wood screws or tapping screws. This relates to a stop device.

[Prior Art] Conventionally, various types of automatic screw fastening devices have been provided, regardless of whether they use electrical rotation or air rotation.

Particularly for those that use air, the screw tightening device is usually held in the hand and the screw is held at the tip.However, most automatic screw tightening devices that use a motor are used by rotating the motor and holding the screw at the tip. There have been many automatic screw fixing devices that perform screw fixing by moving a holding part that holds a screw in the direction of the workpiece.

[Problems to be Solved by the Invention] As described above, an automatic screw fastening device consisting of a rotating device equipped with a holding part for holding a screw at its tip and an advancing/retracting device that advances and retreats this rotating device simply rotates the screw. Since the screw is only sent in the direction of the workpiece according to its pitch, it is suitable for ordinary bolt tightening or screw tightening, but it is not suitable for use with wood screws or tapping screws, which are screws that aim for a driving effect. The situation was ripe.

That is, since the screws are always fed only at a constant pitch, plastic deformation of the workpiece due to the feeding of wood screws, tapping screws, etc. cannot be expected very much, and the screws may loosen due to vibration or the like.

Therefore, the present invention adds a micro-vibration device to a conventional automatic screw-fastening device, and applies micro-vibrations to the screw holding part in the forward-backward direction as the rotating device advances and retreats, thereby achieving not only screw-fastening by mere rotation but also a driving effect. It is an object of the present invention to provide an automatic screw fastening device which also has the following features and which prevents screws from loosening.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an automatic screwdriver comprising a rotating device having a holding portion for holding a screw at its tip, and an advancing/retracting device for advancing and retracting the rotating device. In the stopping device, the rotating device is formed so as to be movable in the direction opposite to the workpiece due to the reaction force of the screw contacting the workpiece, and the advancing/retracting device is provided with a slight movement in the advancing/retracting direction that is activated by the movement of the rotating device toward the opposite side of the workpiece. It is characterized by the addition of a vibration device.

[Examples] Examples of the present invention will be described below along with illustrated examples.

In the present invention, an air cylinder 3 is fixed to the upper part of a frame 2 which is erected on a base 1, and a rod 4 is provided which is movable downwardly and retractably from the air cylinder 3.
A moving case 5 is fixed to the tip, and an advancing/retracting device A is formed.

A motor 6 is fixed to the moving case 5, and a coupling 8 is attached to the output shaft 7 of the motor 6.
An eccentric shaft 9 is fixed via. The eccentric shaft 9 is rotatably supported by the moving case 5 via a bearing 10, and has an eccentric shaft 11 at its tip. Further, a roller 12 is fixed around this eccentric shaft 11.

On the other hand, a holding case 13 that is slightly movable in the vertical direction is fixed to the moving case 5, and a contact piece 14 is positioned at a position of the holding case 13 corresponding to the roller 12 with a slight interval. be.
The movable case 5 is operated by the eccentric wheel 11 and the contact piece 13 which are rotated eccentrically by these motors 6.
A micro-vibration device B for the holding case 13 is formed.

Further, a rotating device C is fixed to the holding case 13. This rotating device C includes a motor 15
and a holding portion 17 such as a screw provided at the tip of the output shaft 16 of the motor 15.

This holding part 17 has a movable cylinder 19 that is movable in the vertical direction loosely mounted in a cylindrical case 18 fixed to the lower part of the rotating device C, and the output shaft 16 of the motor 15 is installed inside the movable cylinder 19. It is formed as follows.
The cylindrical case 18 is communicated with a negative pressure source 20 so that the inside of the movable cylinder 19 is in a negative pressure state. In addition, the movable tube 19 is normally biased downward by a spring 21 installed between the cylindrical case 18 and the movable tube 19, and a sensor for detecting upward movement toward the movable tube 19 A device D is provided. Note that a tip portion 22 is formed at the tip of the output shaft 16 such that it matches the shape of the head of a Phillips screw, for example.

The detection device D detects the upward movement of the movable rod 23 fixed to the movable tube 19, and is configured to move the adjustment tube 25 fixed to the movable rod 23 up and down inside the box body 24 fixed to the holding case 13. The movable body 26 is formed to be movable in the direction, and the movable body 26 is pushed upward by the upward movement of the movable cylinder 19. Further, as the moving body 26 moves upward, it causes a swinging rod 27 provided inside the box 24 to swing, and the swinging of the swinging rod 27 is caused by a proximity sensor 27 provided inside the box 24. It is detected by Note that the moving rod 23 and the adjusting tube 25 are formed so that their relative positions can be adjusted. Further, the relative position between the adjustment tube 25 and the movable body 26 can also be adjusted to provide an appropriate gap 29.

Note that the movable cylinder 19, which is the tip of the holding part 17, and the distal end 22 of the output shaft 16 of the motor 15, the movable cylinder 19 normally protrudes, and the distal end 22 of the output shaft 16 of the motor 15 is inside the movable cylinder 19. It is shaped so that it is located at Furthermore, the tip of the movable tube 19 is
Notch 3 that matches the shape of the head of the screw 30 to be used
1 is formed. For example, if the screw used is a countersunk screw, the notch 31 is cylindrical.
In the case of a round screw (not shown), a notch 31 having a curvature matching the curvature of the round screw is formed.

In FIG. 1, what is provided from the upper surface of the base 1 to the left side of the base 1 is a feeding device E for a non-processed object to be screwed, that is, a workpiece. Although not shown in the drawings, a screw 30 feeding device is also required for feeding the screws 30 one by one below the holding portion 17.

Next, the operation of the automatic screw fastening device according to the present invention will be explained.

First, one screw 30 is sent out below the movable cylinder 19 of the holding part 17 by a screw 30 feeding device (not shown).

Then, due to the negative pressure from the negative pressure source 20 communicated with the cylindrical case 18 of this holding part 19, the screw 30
Its upper end is sucked into the notch 31 of the movable cylinder 19, and the screw 30 is held with the tip thereof facing downward.

Next, the workpiece is transferred to the holding section 17 by the feeding device E.
The motor 15 of the rotating device C is rotated, and the moving case 5 is moved downward by the air cylinder 3.

In this state, the motor 6 fixed to the moving case 5 rotates, and the eccentric wheel 11 also rotates as the motor 5 rotates, but the holding case 13 is moved relative to the moving case 5 due to the weight of the rotating device C. It is located at the lowest end, and holding case 1
3 does not vibrate.

Thereafter, as the air cylinder 3 is fed, the screw 30 adsorbed to the tip of the holding portion 17 comes into contact with the workpiece. Then, the screw 30 is rotated by the rotating device C.
Because it is being rotated by Then, the rotating device C moves slightly upward due to the reaction force of pushing the screw into the workpiece, and the contact piece 14 comes into contact with the eccentric ring 11.

When the contact piece 14 and the eccentric wheel 11 come into contact, the holding case 13 is rotated by the eccentric wheel 11, which is rotated eccentrically by the rotation of the motor 6 provided in the moving case 5.
This will cause slight vibrations in the vertical direction. That is, at this time, the screw 30 is held downward by the air cylinder 3 and rotated by the motor 15, and a slight vibration is generated in the feeding direction by the vibration device B.

As a result, the movable rod 23 fixed to the movable cylinder 19
moves upward, but due to the gap 29 between both 19 and 23, the swinging rod 27 does not swing yet.

Eventually, when the screw 30 is completely pushed into the work, the tip of the movable cylinder 19 comes into contact with the surface of the work. Thereafter, the movable cylinder 19 is maintained at the same position while only the output shaft 16 of the motor 15 of the rotating device C rotates the screw 30, and the vibration device B
It moves downward while being accompanied by slight vibrations in the vertical direction. This means that the movable cylinder 19 moves upward relative to the rotating device C. Along with this upward movement of the movable tube 19, the movable rod 2
The adjustment cylinder 25 fixed at 3 will move further upward.

By moving the adjustment cylinder 25 upward, the moving body 2
6 is pushed upward, and the swinging rod 27 swings in response to the upward movement of the movable body 26. When the swing rod 27 swings, the swing is detected by the proximity sensor 2.
8, the air cylinder 3 acts in the opposite direction to stop the downward movement by the air cylinder 3 and the rotation of the motors 6 and 15, and to move the moving case 5 upward.

That is, by setting the upward movement distance of the adjusting tube 25 in advance, the completion of screw tightening can be detected as a change in distance, so there is no need for a torque detection device or the like to detect when screw tightening has been completed. Become.

The present invention adds a micro-vibration device B in the advancing and retreating direction to the advancing/retracting device A of an automatic screw fastening device. In addition to the feeding, the driving effect by the micro-vibration device B is added, so that screws can be secured that are difficult to loosen or come off.

In addition, as this micro-vibration device B, an eccentric wheel 11 is provided at the tip of the motor 6 fixed to the advancing/retracting device A, and the eccentric rotation of the eccentric wheel 11 is transmitted to the rotating device C, so that no complicated mechanism is required. It is possible to perform minute vibrations without the need for vibration.

Further, the holding part 17 is provided with a function for detecting the completion of rotation of the rotating device C, which has a holding part 17 that holds the screw 30 at its tip, and the completion of downward feeding of the air cylinder 3, that is, the completion of screwing the screw 30. Moving tube 19
Since this is done by detecting the amount of upward movement of the screw, it is possible to detect the completion of screw fastening with a simple device, without requiring a torque detection device or the like as in the conventional case.

Note that it is sufficient for the detection device D to be able to detect the amount of upward movement of the moving cylinder 19.
In addition to the above-mentioned detection device D, many other devices can be used, such as a device that optically detects upward movement, a device that detects magnetically, a device that converts the upward movement into rotational speed using a rack and pinion, and so on. Furthermore, when using the illustrated detection device D, for example, in the case of a countersunk screw, it is necessary to screw the screw until the upper end of the screw coincides with the upper end surface of the workpiece, and the amount of upward movement of the movable cylinder 25 associated with this is , is different from the amount of upward movement when using round screws, but depending on the screws 30 used, the different amounts of upward movement can be adjusted as appropriate by adjusting the relative positions of the moving rod 23 and the adjustment tube 25. The screws used are particularly versatile.

In the above description, a case has been described in which wood screws, tapping screws, or the like are used as the screws 30, but the automatic screw fastening device according to the present invention can be applied to screws other than those screws.

[Effects of the Invention] As described above, the present invention attaches a micro-vibration device to a conventional automatic screw-fastening device, and applies micro-vibrations to the screw holding portion in the forward/backward direction as the rotating device advances and retreats, thereby eliminating the need for simple vibrations. In addition to screw fastening by rotation, it also has a driving effect to prevent screws from loosening.

[Brief explanation of drawings]

Figure 1 is a partially cutaway front view showing the overall outline, Figure 2 is a sectional view taken along the - line in Figure 1, Figure 3 is a sectional view taken along the - line in Figure 1, and Figure 4 is a sectional view taken along the - line in Figure 1. A and B in Fig. 5 are cross-sectional views showing the tip of the holding part to show the screwed state, and Figs. 6 and 7 show the detection device. FIG. A...Advancing/retracting device, B...Micro-vibration device, C...Rotating device, D...Detecting device, E...Feeding device, 1...
... Base, 2 ... Frame, 3 ... Air cylinder, 4 ... Rod, 5 ... Moving case, 6 ... Motor, 7 ... Output shaft, 8 ... Coupling, 9
... Eccentric shaft, 10 ... Bearing, 11 ... Eccentric wheel, 12 ... Roller, 13 ... Holding case, 1
4... Contact piece, 15... Motor, 16... Output shaft, 17... Holding part, 18... Cylindrical case, 19
...Moving tube, 20...Negative pressure source, 21...Spring, 22...Tip, 23...Moving rod, 24...
Box body, 25... Adjustment tube, 26... Moving body, 27...
... Swinging rod, 28 ... Proximity sensor, 29 ... Gap, 30 ... Screw, 31 ... Notch.

Claims (1)

[Scope of Claims] 1. An automatic screw fastening device comprising a rotating device having a holding part for holding a screw at its tip and a forwarding and retracting device for moving the rotating device forward and backward, comprising: An automatic screw fastening device characterized in that it is formed to be movable toward the side opposite to the workpiece due to the reaction force of the screwdriver, and the advance/retreat device is attached with a micro-vibration device in the forward/backward direction that is activated by the movement of the rotating device toward the side opposite to the workpiece. . 2. Claim 1, in which the micro-vibration device is formed by providing an eccentric ring at the tip of a motor fixed to an advancing/retracting device, and transmitting the eccentric rotation of this eccentric wheel to a rotating device.
Automatic screw fastening device as described in section.