JPS626956B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a screw tightening device used for assembling various parts.

Conventional structure and its problems Conventionally, in screw tightening devices that use a means such as a vacuum pump to attract screws and hold them up to the part to be tightened, the screws are held until the screw tightening is completed. Since the suction function continues to operate, it has the disadvantage that it absorbs chips and dust generated when screws are tightened, significantly reducing the function of the screw suction air circuit and stopping the screw suction function. A great deal of effort and time was required for maintenance and maintenance to maintain the suction function, such as cleaning the air circuit for screw suction.

Purpose of the Invention The present invention is intended to eliminate the above-mentioned conventional drawbacks, to eliminate failures of the screw tightening device due to chips, dust, etc. generated during screw tightening, and to improve the reliability of the screw tightening device. The purpose is to

Structure of the Invention In order to achieve the above object, the screw tightening device of the present invention is provided with a detection means for detecting the position immediately before the start of tightening of the screw, and stops the screw adsorption air circuit by the output of the detection means. The configuration is such that the

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In Fig. 1, 1 is a screw, 2 is a chute part that supplies the screw 1, 3 is a catch part for the screw 1 provided at the tip of the chute part 2, and 4 is a separation part that sends out the screws 1 one by one to the catch part 3. device, 5 is screw 1
6 is a bit directly connected to the output shaft of the screw tightening actuator 7, and 8 is a gate formed above the suction pipe 5 and leading to an air circuit (not shown) for screw suction. 9 is a lower holder which is integrally formed with the suction pipe 5 and has a reed switch 10 attached to its outer periphery;
Reference numeral 11 denotes an upper holder for holding the screw tightening actuator 7, and the lower end 12 is magnetized.
The lower part of the upper holder 11 is slidably fitted into the lower holder 9 via a shield plate 13 and a spring 14. Further, 15 is an actuator 16 for vertical driving to drive the suction pipe 5.
This is a bracket for sliding the bit 6 up and down, and the upper arm 15A has the upper holder 11 fixed to it, and the lower arm 15B has the lower holder 9 received. Thus, the lower holder 9 is vertically movable relative to the upper holder 11 between the arms 15A and 15B. 17 is a housing portion of the main body of the device.

Next, the operation of the above configuration will be explained. When a screw tightening start signal is issued from the controller (not shown) of the screw tightening device, the screw suction air circuit and the vertical drive actuator 16 are activated, and the suction pipe 5 and bit 6 start descending, and the second
As shown in the figure, the screw 1 in the catch part 3 is sucked into the suction pipe 5 and carried to the vicinity of the part to be tightened 18 while being held. As shown in FIG. 3A, when the screw 1 reaches the vicinity of the portion to be tightened 18, the suction pipe 5 first stops. Next, bit 6 is shown in Figure 3B.
When the screw 1 is lowered to the position where it is pressed against the part to be tightened 18 against the spring 14, as shown in FIG. 1 causes the magnetic force of the lower end 12 of the upper holder 11 to actuate the reed switch 10 of the lower holder 9. The output signal of this reed switch 10 stops the screw adsorption air circuit, and the screw tightening actuator 7
The screw 1 is connected to the tightened part 18 by the bit 6 directly connected to the
Start tightening.

At this time, even if the screw suction air circuit is stopped, the screws are held by the suction pipe 5, the bit 6, and the part to be tightened 18, so even if the suction function is stopped, there is no problem in holding the screws.

In this way, according to this embodiment, since the screw suction air circuit is stopped immediately before the start of screw tightening on the part to be tightened, chips, dust, etc. can completely eliminate the suction of
Failure of the screw tightening device due to these factors can be prevented.

In other words, since screw tightening is performed with the screw suction air circuit stopped, chips, dust, etc. generated between bit 6, screw 1, and tightened part 18 do not enter into the suction air circuit. be.

In the embodiment of the present invention, a reed switch is used as a means for detecting the position immediately before the screw starts to be tightened, but there is no problem in using a detection means such as a limit switch or a phototube switch, and the same effect can be obtained. can get.

Effects of the Invention As described above, according to the present invention, the air circuit for attracting screws is stopped before starting to tighten the screws, and air suction is stopped. This prevents screws from being sucked into the air circuit, eliminating any failures in the screw tightening device, etc.
Therefore, the reliability of the screw tightening device is greatly improved, and maintenance and maintenance of the screw tightening device can be greatly reduced in labor.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a vertical cross-sectional view of a screw tightening device with the air circuit for screw adsorption omitted, FIG. Figure 3A is a vertical cross-sectional view of the main part immediately before the start of screw tightening when the air circuit for screw adsorption is activated, and Figure 3B is a vertical cross-sectional view of the main part immediately before the start of screw tightening when the air circuit for screw adsorption is stopped. . 1...screw, 2...chute part, 3...catch part,
4... Separation device, 5... Adsorption pipe, 6... Bit, 7
...actuator for screw tightening, 8...gate part, 9...
Lower holder, 10... Reed switch, 11... Upper holder, 12... Lower end of upper holder, 14
...Spring, 15...Bracket, 16...Vertical drive actuator, 18...Tightened part, l...Misalignment.

Claims (1)

[Claims] 1. A screw chute portion, a screw catch portion provided at the tip of the screw portion, a separation device that feeds the screws one by one to the catch portion, a bit directly connected to the output shaft of the screw tightening actuator, and A suction pipe that suctions and holds a screw on the tip of the bit,
A screw tightening device having a gate portion leading from the suction pipe to an air circuit for screw suction, and a bracket for driving the suction pipe and the bit vertically by an actuator for vertical driving, wherein the actuator for vertical driving is A detection means is provided to detect the position just before the screw starts to be tightened while the bit is being driven downward, and the output of this detection means stops the air circuit for suctioning the screw and sucks the screw when tightening the screw. A screw tightening device configured to prevent