JPH02106232A - Screw fastening device - Google Patents

Abstract

PURPOSE:To enable the certain practice of screw fastening by a driver by providing a confirmation part outputting an end signal when the rotation torque of the driver is reached to a determined value and the vertical position is reached to a determined position. CONSTITUTION:A driver 3 is rotated by the rotation driving signal S3 of a driving part 10 to fasten a screw 20 held at the top end of the driver 3. The fastening of the screw 20 is detected by a detection part 17. A confirmation part 8 is provided with gate circuits G1-G3. The circuit G1 is connected with an output signal S4 and a detection signal S1, and when a torque limiter 2 is reached to a determined rotation torque, the detection signal S1 by a first sensor 5 is outputted, and a signal is sent to the gate circuit G3. The circuit G2 is connected with a circuit driving signal S3 and a detection signal S2, and after the determined rotation of the driver 3, when the signal S2 by a second sensor 6 comes not to be outputted, a signal is sent to the circuit G3, which outputs an end signal 5 when receives the signals from the both G1 and G2.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a screw tightening device that tightens a predetermined screw by being equipped with a motor that rotates a driver and a lifting mechanism that raises and lowers the driver. The flange fixed to the driver and the driver are arranged so as to be offset from each other in the vertical direction of the driver, so that the lowering of the flange can be detected first. A first sensor and a second sensor that detects the descent of the flange portion following detection by the first sensor are provided, and detection signals from the first and second sensors and from the drive unit are provided. The present invention is configured to include a confirmation unit that receives a rotational drive signal sent to the motor and an output signal, and outputs a screw tightening completion signal.

[Industrial application field]

The present invention relates to a screw tightening device that tightens a predetermined screw by including a motor that rotates a driver and a lifting mechanism that lifts and lowers the driver.

2. Description of the Related Art In an assembly process of an electronic device, a member to be attached is locked by tightening a screw with a screwdriver to a member having a tapped hole.

However, when tightening a large number of screws with such a screwdriver, the number of assembly steps increases, so recently, in order to save assembly time, tightening is performed by automatically rotating the screwdriver. Screw tightening devices began to be used.

Therefore, it is important for such a screw tightening device to be configured so that each screw can be reliably tightened even when tightening a huge number of screws. It was constructed as shown in the conventional explanatory diagram in FIG. FIG. 4(a) is a configuration diagram, and FIG. 4(b1) to (b3) are side sectional views showing the state in which the screws are tightened.

As shown in FIG. 4(a), the support base 7E is slidably engaged with the shaft 7D provided on the frame 7C, and the support base 7E is moved by the arrow 9 by the cylinder 7A driven by the drive unit 7B. A lifting mechanism 7 formed to be raised and lowered in the Z direction, a motor 1 loaded on a support base 7E and rotationally driven by a rotation signal S3 from a drive unit 10, and a rotational drive of the motor 1 is transmitted to a shaft 12. Torque limiter 2
A rotating mechanism 11 having a rotating part 11 consisting of a rotating part 11 was provided, and the driver 3 was configured to be locked to a shaft 12 via a spring 13.

Further, a suction device 14 is provided at the tip 38 of the driver 3, and the screw 20 to be tightened is held by sucking air through the tube 14 in the direction of the arrow.

Further, each of the drive unit 7B that drives the cylinder 7A and the drive unit 10 that drives the motor 1 is driven by the control unit 16.

Therefore, the member 21 having the tapped hole 21A is attached to the table 2.
3, position the mounted member 22 by overlapping the member 21, and hold the screw 20 to be tightened at the tip 3A, so that the tip of the screw 20 is tapped by the lifting mechanism 7. The screw 20 is lowered until it comes into pressure contact with the hole 21A, and the screw 20 is tightened into the tapped hole 21A by rotation of the rotation mechanism 11, so that the member 22 to be attached is locked to the member 21.

Further, as shown in (b1), the tightening of the screw 20 is performed by applying the spring pressure P of the spring 13 to the driver 3 by lowering the elevating mechanism 7 by a predetermined amount, and the tip of the screw 20 is pushed into the tapped hole by the spring pressure P. 218, and by rotation of the driver 3, the screw 20 is screwed into the tapped hole 21A.

When the screw 20 is screwed in as shown in (b2), the rotational torque of the driver 3 increases, and when the rotational torque reaches a predetermined value, the torque limiter 2 controls the motor 1 of the driver 3. The transmission of rotational drive is disconnected, and an output signal S is sent from the torque limiter 2 to the control unit I6.
4 is output.

Therefore, the control section 16 lowers the driver 3 to a predetermined position using the control signal D1 outputted to the drive section 7B, and then rotates the driver 3 for a predetermined time using the control signal D2 outputted to the drive section 10. The completion of tightening the screw 20 is confirmed by the output signal S4, and upon receiving the output signal S4, the driver 3 is raised to its original position in preparation for tightening the next screw.

[Problem to be solved by the invention] However, the output signal S from such a torque limiter 2
4 confirms that the tightening of the screw 20 is completed. If the screw 20 to be tightened is not held at the tip of the driver 3 and is idling, the output signal S4 from the torque limiter 2 is determined by rotating the driver 3 for a predetermined period of time. This can be determined by the control unit 16 when the output is no longer output, but as shown in (b3) in FIG.
2, the screw 20 may not be completely tightened into the tapped hole 21A.

In such a state, even if the screw 20 is not completely tightened into the tapped hole 21A, the screw 20 will no longer rotate and the rotational torque will reach a predetermined value, so normal tightening is treated as completed. , the next tightening operation is performed.

Therefore, after the screws have been tightened, it is necessary to visually check the parts where the screws 20 and the tapped holes 21A were not completely tightened due to poor fitting, which requires a lot of man-hours. become.

Furthermore, such a visual check can sometimes cause oversights, making it difficult to obtain high reliability.

Therefore, an object of the present invention is to ensure that screws are tightened by a screwdriver.

[Means to solve the problem]

FIG. 1 is a diagram explaining the principle of the present invention.

As shown in FIG. 1, a flange fixed to a driver and a flange that first detects the descent of the flange are arranged so as to be offset from each other in the vertical direction of the driver. A first sensor and a second sensor that detects the descent of the flange portion following detection by the first sensor are provided, and the detection signals from the first and second sensors and the motor from the drive unit are provided. The present invention is configured to include a confirmation section that receives the rotational drive signal and the output signal sent to the screwdriver and outputs a screw tightening completion signal.

With this configuration, the above-mentioned problem is solved.

[Effect]

In other words, by providing a flange part on the driver and having two sets of sensors detect the flange part, the lowered position of the driver can be detected, and when tightening is completed, it can be determined whether the driver is in the specified position or not. It is designed to be checked by a sensor.

Therefore, if there is a distance M between the screw head and the member to be attached as described above, the position of the driver will be shifted by the distance M compared to when normal tightening is completed. It can be determined by the detection by the sensor that the screw is not completely tightened.

Therefore, it is possible to determine a state in which the screw is not fully tightened, which has not been detected in the past, and it is possible to prevent such a state in which the screw is not fully tightened, thereby improving reliability.

〔Example〕

The present invention will be explained in detail below with reference to FIGS. 2 and 3. Fig. 2 is a configuration diagram of an embodiment according to the present invention, Fig. 3 is an explanatory diagram of the present invention, (a1) to (a3) are explanatory diagrams of detection of the flange part, and (b) is a circuit diagram of the confirmation part. be. The same reference numerals indicate the same objects throughout the figures.

As shown in FIG. 2, the tribar 3 is provided with a flange portion 4, and a detection portion 17 in which first and second sensors 5 and 6 are disposed is provided near the flange portion 4.
Detection signal Sl output from the first and second sensors 5 and 6
, S2 are sent to the confirmation unit 8, and the rest of the configuration is the same as described above.

Further, the confirmation unit 8 is configured to receive a rotational drive signal S3 sent from the drive unit 10 and an output signal S4 sent from the torque limiter 2.

Therefore, first, the drive unit 7B is commanded to drive by the control signal D1 from the control unit 9, so that the cylinder 7 is driven, the support base 7E is lowered, the drive bar 3 is lowered to a predetermined position, and then the cylinder 7 is driven. Then, the drive unit 10 is commanded to drive by the control signal D2 from the control unit 9, and the drive unit 10 outputs a rotation drive signal S3, and the rotation of the motor 1 causes the driver 3 to rotate. The screw 20 held at the tip is tightened.

The tightening of the screw 20 is performed as shown in (a1) to (a1) in FIG.
Detection is performed by the detection unit 17 as shown in a3).

The detection unit 17 is provided with a first sensor 5 and a second sensor 6 located below the first sensor 5. The two sensors 6 are formed so that they are each irradiated with light emitting elements 6A.

Therefore, as shown in (a1), before the screw 20 is tightened, the flange portion 4 is positioned as shown by the dotted line, and the irradiation light of the light emitting element 5A is blocked, but the light emitted from the light emitting element 5A is blocked. Since the irradiation light of the element 6A is not blocked, the first sensor 5 does not output the detection signal light S1, but the second sensor 6 outputs the detection signal light S2.

Further, when the screw 20 is completely tightened, the flange portion 4 is positioned as shown by the solid line, and in this case, the detection signal light S1 is emitted from the first sensor 5, which is the opposite of the above. However, the second sensor 6 does not output the detection signal light S2.

Furthermore, as shown in (a2), if the screw 20 is not held at the tip of the driver 3, the descent of the driver 3 will be below the predetermined position, so the detection from the first and second sensor breasts 6 will not be possible. Both signals Sl and S2 will be output.

Furthermore, as shown in (a3), if the screw 20 is not fully tightened and a gap M is created between the head of the screw 20 and the attached member 22, the driver 3 will not be able to descend to the specified position. Therefore, the flange portion 4 connects the light emitting elements 5^ and 6.
The irradiation light from both the first and second sensors 5,
6, both detection signals Sl and S2 are no longer output.

Such detection signals Sl and S2 are sent to the confirmation unit 8 shown in (b).
The tightening condition of the screw 20 can be determined by checking the condition.

The confirmation unit 8 includes gate circuits Gl, G2 . G3 was established,
The output signal S4 and the detection signal S1 are connected to the gate circuit G1, and when the torque limiter 2 reaches a predetermined rotational torque, the detection signal S1 from the first sensor 5 is output, thereby sending a signal to the gate circuit G3. At the same time, the rotation drive signal S3 and the detection signal S are sent to the gate circuit G2.
2 is connected, and after the driver 3 performs a predetermined rotation, the second
When the detection signal S2 from the sensor 6 is no longer output, a signal is sent to the gate circuit G3, and the gate circuit 63 outputs a termination signal 5 when signals are output from both gate circuits Gl and 62. do.

Moreover, since such a detection part 17 is formed so as to be locked to the frame 7C by an adjustment screw 178,
By turning the adjustment screw 17^, the first and second sensors 5, 6
It is formed so that fine positional adjustments can be made in the direction of the arrow.

Therefore, after the driver 3 performs a predetermined rotation, the end signal S5 is output only when the screw 20 is completely screwed into the tapped hole 21A with a predetermined rotation torque, and the screw 20 is completely screwed into the tapped hole 21A. If the torque limiter 2 is missing, the output signal S4 will not be obtained from the torque limiter 2, and the detection signal S2 that should not be output will be output, and if the tightening is incomplete, the detection signal S1 that should be output will not be output. By doing so, it is possible to prevent the end signal S5 from being output in any case.

Therefore, as shown in FIG. 2, the end signal S5 is sent to the control section 9.
By sending the command, the control unit 9 can confirm the completion of each screw tightening command with the completion signal S5 and issue the next tightening command, thereby ensuring reliable tightening. be able to.

〔Effect of the invention〕

As explained above, according to the present invention, when the driver performs a predetermined rotation, the rotational torque reaches a predetermined value,
Moreover, the completion of screw tightening can be determined by the confirmation section which outputs a completion signal when the vertical position of the driver reaches a predetermined position.

Therefore, it is possible to reliably detect incomplete screw tightening, which could not be determined in the conventional manner, and reliability is improved, which has a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention. FIG. 2 is a configuration diagram of an embodiment according to the present invention. FIG. 3 is an explanatory diagram of the present invention, in which (a1) to (a3) are explanatory diagrams for detecting the flange portion, and (b) is a circuit diagram of the confirmation portion. Figure 4 is a conventional explanatory diagram, (a) is a configuration diagram, (b1) -
(b3) shows a side sectional view of the state in which the screws are tightened. In the figure, ■ is the motor, and 2 is the torque limiter. 3 is a driver, 4 is a flange part. 5 is a first sensor, 6 is a second sensor. 7 is the lifting mechanism, and 8 is the confirmation section. Reference numeral 9 indicates a control section, and 10 indicates a drive section. Incurable 5th month Dodo 7-cho 2 Name day/month Gtsuth f mouth (asu (ku 2) toot [F]

Claims (1)

[Claims] A motor (1) that rotationally drives a driver (3), a control unit (9) that controls the drive of the motor (1) via a drive unit (10), and the motor (1). a torque limiter (2) that outputs an output signal (S4) when the rotational torque transmitted from the drive to the driver (3) reaches a predetermined value; and a lifting mechanism (7) that lifts and lowers the driver (3). A screw tightening device that tightens a predetermined screw by lowering and rotating the driver (3), comprising: a flange portion (4) fixed to the driver (3);
a first sensor (5) that is arranged at a predetermined interval in the vertical direction (Z) of the driver (3) to first detect the descent of the flange portion (4); A second sensor (6) that detects the descent of the flange portion (4) following the detection by the first sensor (5) is provided, and the detection by the first and second sensors (5, 6) is provided. Upon receiving the detection signals (S1) and (S2), the rotational drive signal (S3) sent from the drive unit (10) to the motor (1), and the output signal (S4), the screw tightening is completed. Signal (S5
) A screw tightening device characterized in that it is equipped with a confirmation section (8) that outputs the following.