JPH02243228A - Automatic screw fastening device - Google Patents

Abstract

PURPOSE:To improve the efficiency for automatic screw fastening by providing a spacer for forming a gap between a sleeve and screw feeding part at the screw setting time, in an automatic screw fastening device where the rotating tool of an air driver, etc., are used. CONSTITUTION:In the case of setting a screw 100 to a bit 7, a gap 32 is formed between a sleeve 11 and screw feeding part 16, when a spacer 31 is abutted on the screw feeding part 16. When the screw 100 setting is started in this state, the air blown out of a blowout port 20 blows up a screw head part 101 and the one part is flown to the external part from the gap 32. In this case, if the flowout area is taken larger than the gap of the screw head part 101 and sleeve 11, the air is flown more to the gap 31 of smaller resistance. So, the air amount flowed into a suction part 6 is reduced, the screw 100 stops vibrating and it can be set by being engaged with the bit 7 surely and quickly.

Description

[Detailed Description of the Invention] [Summary] This invention relates to an automatic screw tightening device using a rotating tool such as an electric screwdriver or an air driver, which can stably set a screw in a bit in a short time, and also prevents screws from tightening when tightening the screw. a screw feeder equipped with an air outlet that holds the screw and allows compressed air to blow up the head of the screw to pass through, the purpose of which is to avoid damaging the groove in the head;
Holds the bit rotatably.

The screw is also provided with a suction part and a vertically movable sleeve, and when setting the screw, the screw blown up from the screw supply part is sucked into the suction part through the sleeve that abuts the screw supply part, and is set in the bit. In the automatic screw tightening device comprising a rotary tool, either the sleeve or the screw supply section is provided with a spacer for forming a gap between the two members during screw setting.

[Industrial application field]

The present invention relates to an automatic screw tightening device using a rotating tool such as an electric screwdriver or an air screwdriver.

With the progress of factory automation, various types of work are being performed by robots, and relatively sophisticated assembly work of mechanical parts is also being performed by robots7). In assembly work performed by robots, in addition to work in which one part is installed at a predetermined position on the other, there is also work in which mechanical parts are fastened to other parts or devices by screw tightening. The screw tightening work is performed by a dedicated screw tightening machine equipped with a rotary tool or a robot equipped with a rotary tool, and screws are automatically supplied to the rotary tool from a screw feeder.

[Conventional technology]

FIG. 4 is a front view showing the structure of a conventional automatic screw tightening device, in which 1 is a rotary tool and 2 is a screw feeder.

The rotary tool 1 is supported by a robot arm 3 movable in the X+3'+2 direction, and includes a motor 4, a torque adjustment section 5, and a suction section 6, and rotatably holds a bit 7. The suction unit 6 is connected to a vacuum pump 8 via a suction solenoid valve 9, and the solenoid valve 9 is controlled by a controller 10.

A sleeve 11 is supported within the adsorption section 6 so as to be movable up and down.
The sleeve 11 is urged downward by a spring 12 and is locked in the illustrated state.

The sleeve 11 has an inner diameter slightly larger than the outer diameter of the head of the screw 100. In addition, the lower part of the sleeve 11 determines whether or not the screw 100 is attracted (determined by irradiating a light beam slightly below the bit 7 from the side of the sleeve 11).
A photoelectric sensor 13 is provided. Photoelectric sensor 13
is a sensor head 131 that emits light and receives reflected light.
, an amplifier 13□ that has a built-in light-emitting element and a light-receiving element and converts the intensity of reflected light into an electrical signal, and an optical fiber 13 that connects the sensor head 13° and the amplifier 13□. Consists of.

As shown in FIG. 5, the screw feeder 2 includes a screw feeder 1 having a hole 15 for holding one screw 100 that is continuously fed from a parts feeder (not shown) and falls down a chute 14.
It is equipped with 6. The screw supply section 16 is connected to the compressor 17
An air flow path 19 communicating with the blow-up electromagnetic valve 18 and an air outlet 20 communicating with the air flow path 19 are provided.
, can move in the B direction. The screw 100 is separated and held by the hole 15 by moving the screw supply section 16 in the direction of arrow A from the state shown in FIG. 5, and the screw centration described later is performed in this state. The air outlet 20 is arranged at a position facing the back side of the head 101 of the screw 100 held in the hole 15.

The solenoid valve 18 is controlled by the controller 10.

The screw 100 is set in the bit 7 in the following steps.

When setting the screws, the rotary tool 1 is moved by the arm 3 to bring the sleeve 1f into contact with the screw supply section 16 at a position facing the hole 15. In this state, the head 101 of the screw 100 held in the hole 15 is located within the sleeve 11 with a small gap therebetween. In this state, controller 1
When the solenoid valves 9 and 18 are turned on and the vacuum pump 8 and compressor 17 are operated by
0 is suctioned and set in the bit 7 (the cross groove of the screw head 101 is engaged with the bit), but at this time, the compressed air supplied to the air passage 19 from the compressor 17 is blown out from the air outlet 20. The screw head 101 is blown up to ensure setting. Completion of this screw setting can be confirmed by the photoelectric sensor 13. This screw head 1
01 was made by the applicant on August 20, 1988.
This was disclosed in Japanese Patent Application No. 63-206764 filed in 1983. By the way, if the groove of the screw head 101 is not completely engaged with the bit 7 when the screw is suctioned at 7 bits, the next time the rotary tool 1 is moved to the screw tightening place and the screw tightening operation is performed, As shown in FIG. 6, the hatched portion of the groove 102 of the screw head 101 may be scratched. The size of this scratch is 0.1 to 0.3 t for M3 Phillips screws.
It is so small that it is almost invisible to the naked eye. However, in the case of a precision machine such as a magnetic disk drive, which is extremely sensitive to dust, if metal fragments generated by this scratch are inside the machine, there is a risk of serious trouble such as a head crash. This problem is solved by blowing up the screw head 101 as described above.

(Problem to be Solved by the Invention) By the way, since there are variations in the diameter of the screw head 101, the inner diameter of the sleeve 11 should be adjusted to the diameter of the screw head 101 so that the screw 100 can be reliably sucked into the sleeve. It is slightly thicker than the outer diameter (about 0.5 mm with an M3 Phillips screw). As a result, as shown in FIG. 7, air constantly flows into the suction section 6 from the gap between the screw head 101 and the sleeve 11 during screw suction. In order to increase the suction force during suction, it is important that unnecessary air does not flow into the suction part 6 from other than the gap between the sleeve 11 and the screw head 101, and between the suction part 6 and the rotary tool 1.

The gap between the suction part 6 and the sleeve 11 is made as small as possible to reduce air leakage. Due to this structure, the following problems arose when the screw was blown up.

That is, as shown in FIG. 8, the compressed air blown from the air outlet 20 pushes up the screw head 101, and this air passes through the gap between the screw head 101 and the sleeve 11 and begins to accumulate in the suction part 6. The accumulated air acts to push the screw head 101 downward. As a result, the screw 100 vibrates violently up and down at the position where it contacts the bit 7, and the screw head 10
The groove 102 of No. 1 no longer engages with the bit 7. As the airtightness of the suction part 6 increases, there is no place for air to escape, so the screw 1
The vibration of 00 is large.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic screw tightening device that can stably set a screw in a bit in a short time and does not damage the screw head during screw tightening.

[Means to solve the problem]

FIG. 1 is an explanatory diagram of the principle of the present invention, in which members similar to the conventional ones are indicated by reference numbers. In the figure, 31 is a spacer.

The spacer 31 is provided on either the sleeve 11 or the screw supply section 16 to form a predetermined gap 32 between the sleeve 1 and the screw supply section 16 when the screw 100 is sucked and set. This figure shows an example in which a plurality of spacers 31 are provided protruding from the lower end of the sleeve 11.

[For production]

When the spacer 11 is brought into contact with the screw supply section 16 when setting the screw 100 in the bit 7, a gap 32 is created between the sleeve 11 and the screw supply section 16 due to the presence of the spacer 31.
is formed.

When the screw lOO starts to be centered in this state, the air blown out from the air outlet 20 not only blows up the screw head 101, but also partially flows out through the gap 32 to the outside. In this case, if the outflow area of the gap 32 is made larger than the gap between the screw head 101 and the sleeve 11, more air will flow through the gap 31 where the resistance is lower. Further, since the gap 32 is located close to the air outlet 20, even more air flows out from the gap 32.

Therefore, the amount of air flowing into the suction part 6 is reduced and the screw 10
0 does not vibrate, making it possible to engage and set the screw 100 with the bit 7 reliably and quickly. As a result, damage to the screw head during subsequent screw tightening can be prevented.

〔Example〕

The present invention will now be described in detail with reference to FIGS. 2 and 3.

FIG. 2 shows a first embodiment.

FIG. 2 is a perspective view showing the main structure of the automatic screw tightening device of this example, and the spacer 31 shown in FIG. 1 is integrally provided at the tip of the sleeve 11 in a protruding manner.

The other configurations are the same as in FIG. 4.

By providing this spacer 31, as explained in connection with FIG. quantity decreases. Therefore, when setting the screw, which was a problem in the past,
o vibration is eliminated, and the screw 100 can be reliably and quickly engaged with the bit 7 and set. Further, it is possible to prevent damage to the screw head 101 when tightening the screw afterwards.

FIG. 3 shows a second embodiment.

FIG. 3 is a perspective view showing the main structure of the automatic screw tightening device of this example. In the figure, 41 is a spacer placed on the screw supply section 16 so as to come into contact with the tip of the sleeve 11.

In the case of this example as well, a part of the air blown out from the air outlet 20 flows through the spacer 11 formed by the spacer 41.
It flows out from the gap between the screw supply section 16 and the screw supply section 16, and the same effect as in the previous example can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the screw blown up by compressed air is set by engaging with the bit without vibration, so that the screw can be set into the bit reliably and quickly. It is possible to improve the efficiency of automatic screw tightening. Further, damage to the screw head during subsequent screw tightening can be prevented.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the principle of the present invention, Fig. 2 is a perspective view showing the main structure of an automatic screw tightening device according to the first embodiment of the present invention, and Fig. 3 is a diagram illustrating the principal structure of the automatic screw tightening device according to the first embodiment of the present invention. FIG. 4 is a front view showing the structure of a conventional automatic screw tightening device; FIG. 5 is a perspective view showing the structure of a conventional screw feeder; Figure 7 is an explanatory diagram of the groove shape of the screw head, Figure 7 is an explanatory diagram of the operation of the main parts of a conventional automatic screw tightening device, and Figure 8 is an explanatory diagram of problems with the conventional automatic screw tightening device. 7 is a rotating tool, 7 is a bit, 11 is a sleeve, 16 is a screw supply part, 20 is an outlet, 31.41 is a spacer, and 32 is a gap. Illustration of the principle of the present invention: Figure 1, Figure 3, Figure 4, Figure 6, Figure 5. Conventional automatic screw tightening! Figure 7 Figure 8

Claims (1)

[Claims] A screw supply unit (16) that holds a screw and is equipped with an air outlet (20) through which compressed air blows up the head of the screw, and that rotatably holds a bit (7). In addition, the suction part (
6) and a vertically movable sleeve (11), and when setting a screw, the screw blown up from the screw supply part (16) is transferred to the suction part through the sleeve (11) that comes into contact with the screw supply part (16). An automatic screw tightening device comprising a rotary tool (1) that is suctioned by a rotary tool (1) and set in the bit (7), wherein a screw is set in either the sleeve (11) or the screw supply section (16). An automatic screw tightening device characterized in that a spacer (31) is provided for forming a gap (32) between the sleeve (11) and the screw supply section (16).