JPS5819430B2 - Vacuum suction type automatic screw tightening machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum suction type automatic screw tightening machine, and its purpose is to suck chips generated during screw tightening into an air passage such as a suction pipe or a vacuum filter.
To provide an inexpensive automatic screw tightening machine that prevents deterioration of vacuum suction ability due to rotation and sliding of a bit and clogging of a vacuum filter, and always performs reliable screw tightening.

The conventional method will be explained below with reference to FIG.

Reference numeral 1 denotes a bit, which is interlocked with the piston rod 3 of the cylinder 2 and connected to a driver (not shown).

A suction pipe 4 is attached to the outer periphery of the bit 1 so as to be able to slide back and forth with the bit 1, and a suction port 5 is fixed to the lower part of the suction pipe 4.

The upper part of the suction pipe 4 is connected to a switching valve 6, and a vacuum pump 7 is connected to the tip thereof.

The switching valve 6 is also connected to a compressor 8, and the compressor 8 is also connected to another electromagnetic valve 9.

Solenoid valve 9 is port 2 of cylinder 2 for upper and lower driver
Each is connected by two tubes.

Next, the operating state of the conventional example will be explained.

FIG. 8 shows a steady state, in which the cylinder 2 is stopped at the upper limit and the driver is not rotating.

When the solenoid valve 9 is energized and the driver is rotated by the activation signal, the driver begins to descend.

The vacuum pump 7 is always in operation and constantly sucks air from the suction port 5.

The screw is sucked into the suction port 5 during the descent.

The suction port 5 descends further with the screw still attached to the suction port 5 and tightens the screw onto the workpiece, but if the position of the screw and workpiece is misaligned at this time, the screw will not enter the pilot hole of the workpiece.
It rotates on the surface of the workpiece, creates scratches on the workpiece, and inhales the chips.

Furthermore, even during normal screw tightening, minute powder is sucked in due to the friction between the bit 1 and the screw head.

Furthermore, if a suction error occurs and the bit 1 descends without suctioning the screw, the bit will hit the workpiece and rotate, causing large scratches on the workpiece and causing the chips to be inhaled.

In this way, chips and fine powder are sucked in in various forms from the suction port 3 Therefore, chips and fine powder adhere and accumulate inside the piping, the switching valve 6, the suction pipe, and the vacuum pump, impairing these functions. It will stop it.

At the same time as screw tightening is completed, the screwdriver stops rotating, a completion signal is issued, the electromagnetic valve 9 is de-energized, and the cylinder 2 is raised.

During the ascent, the switching valve 6 is switched to stop suction, and the compressor 8 and suction pipe 4 communicate with each other to blow out air from the suction port.

At this time, the fine powder and chips that have been inhaled up to now are blown out from the suction port along with air.

The switching valve 6 is always in communication with the vacuum pump 7 to suck air, and when the driver starts to rise and kicks the switch lever 11 with the knob 10 that is linked to the piston rod 3, the switching valve 6 is activated. The air suction operation is temporarily stopped, and the air from the compressor is discharged from the suction port 5 for a short period of time.

Note that the switch lever 11 does not operate when the knob 10 is lowered.

The disadvantage of this conventional method is that air is constantly sucked in from the suction port, so the vacuum pump is constantly rotating, which not only wastes power, but also causes air to be contained in the atmosphere even when not suctioning screws. Since the dust is being suctioned, more dust than necessary is sucked into the piping, the suction pipe 4, the switching valve 6, and the vacuum pump 7.

Therefore, the performance of each part is likely to deteriorate due to the accumulation of dust.

Further, the switching valve 6, the knob 10, and parts for attaching these are necessary for air blowing, and the structure is complicated, which not only increases cost but also reduces reliability.

The present invention aims to eliminate the above-mentioned conventional drawbacks and provide a vacuum suction type automatic screw tightening machine that has a simple structure, low air consumption, low cost, and high reliability.One embodiment of the present invention will be described below. Trees illustrated by figures 1-7.

In the figure, 12 is a fixed bracket, and a piston rod 14 and a guide 15 of a cylinder 13 are fixed to this bracket 8.

16 is the driver base, this driver base 16
As shown in FIG. 1, a cylinder 13 is fixed to the right side, a driver 17 is fixed to the left side, and a bearing 18 which is slidable on a guide 15 is fixed to the center part.

Reference numeral 19 denotes a female tapered cylinder, which has an acid taper 20 formed at its lower part, and is fixed to the driver base 16 with the center of this acid taper 20 and the center of the driver 17 aligned.

A bit holder 21 is connected to the driver 17 by a joint 22.

23 is a suction pipe, and a male taper 24 that fits into the acid taper 20 is formed at the top, and a through hole 25 is provided at the top to maintain airtightness while the bit holder 21 is slidable and rotatable. It is formed by the center and laziness.

A compression spring 26 is set between the driver 17 and the upper end surface of the suction pipe 23, and is always biased so that the acid taper 20 and the male taper 24 fit together, and the center of the driver 171 is aligned with the center of the bit holder 21. It is designed to fit.

A suction port 27 is fixed to the upper side surface of the suction pipe 23, and a tube 28 is connected to the tip of the suction port 27.

Put compressed air into the cylinder 13 and use the driver 17
At the same time as the screwdriver 17 begins to descend, air is sucked in from the tube 28, and when the screw tightening is completed, the suction is stopped, and at the same time, the cylinder 13 rises together with the driver 17.

29 is a suction port, a hole 31 slightly larger than the diameter of 300 screws is formed at the bottom, and a bit guide hole; 32 at the center.
is formed.

It should be noted that the bit 33 is fixed to the bit holder 21 intermittently with the bit holder 21.

A pair of inclined chutes j4 are fixed to the lower end of the bracket 12, and the distance between the pair of chutes 340 is set by the screw 3.
The screws are fed one by one in a hanging state, slightly deeper than the diameter of the neck of the screw.

35 is an L-shaped catcher, which is swingably attached to the bracket 12 by a shaft 36. A compression spring 37 is set on the upper part of the shaft 36 between the L-shaped catcher 35 and the bracket. , the tip of the catcher 35 is biased so as to come into contact with the end of the chute 34.

A U-shaped notch 38 is formed at the tip of the L-shaped catcher 35, which catches the screws 30 sent one by one from the chute 34, so that the center of the head of the screw 30 matches the center of the bit 33. It is supposed to be done.

With the screw caught in the L-shaped catcher 35, the screw is sucked into the hole 31 as the bit 33 rotates and descends while sucking air from the suction port.

In this state, the cylinder 13 further descends (then the suction port 27 comes into contact with the workpiece 39 and stops, and then the cylinder 13
3 descends, the screw 30 is inserted into the hole 4 of the workpiece 39.
0 and tighten the screw into the prepared hole 42 of the workpiece 41.

FIG. 6 is an air circuit diagram, and the flow of air will be explained in detail using this diagram.

A vacuum generator 45 generates a vacuum using compressed air on the principle of an atomizer, and a muffler 46 is fixed to the outlet of the vacuum generator.

A compressor 47 is connected to the solenoid valve 43 through a tube 48.

The cylinder 13 is also connected to a solenoid valve 43 through a tube 49 and through a tube 50.

On the other hand, the vacuum generator 45 is connected to the tube 5 by the tube 51.
0, and is connected to a tube 53 by a tube 52.

It is also connected to a solenoid valve and a vacuum filter 44 through a tube 53, and is now connected to a suction port 29 through a tube 28 and suction pipe 23.

In the above air circuit, when the activation signal is input, the driver rotates, the solenoid valve operates, and the cylinder 13 begins to lower and suck air from the suction port 29.

At the same time as the screw tightening is completed, the solenoid valve and driver are de-energized, the compressor and tube 49 are communicated, and the compressed air accumulated in the cylinder 13 and used during the descent is transferred to the tube 50, solenoid valve 53, and vacuum filter 44. , tube 28, and suction pipe, and is released from the suction port 29.

The flow rate of the air flowing through the suction port 29, the suction pipe 23, the tube 28, the vacuum filter 44, the tube 52, and a part of the tube 53 during adsorption is significantly higher than that of the compressed air in the cylinder 13 due to vacuum suction. For,
Chips and the like sucked in during suction are completely discharged from the suction port 29.

Also, a part of the air in the cylinder 13 is exhausted from the muffler 46 through the vacuum generator, but since the muffler 46 has a large resistance, the amount of air does not have a large effect on the exhaust of chips and the like.

Further, a second embodiment will be explained with reference to FIG.

Most of the parts are the same as in Figure 6, so only the different parts will be described.

In this case, a vacuum pump 54 is installed instead of the vacuum generator 450, and the tube 55 is passed through the solenoid valve 56.
Connected to 2.

The tube 51 is not needed and has been removed, and the solenoid valve 56
is interlocked with the solenoid valve 43.

In this second embodiment, all of the compressed air accumulated in the cylinder is discharged from the suction port 29, allowing more complete discharge of chips and dust.

As described above, according to the present invention, air is sucked from the suction port only when the cylinder is lowered, and not when the cylinder is raised or in a steady state, which reduces the amount of air consumed. At the same time, it is economical as there is less dust, and it is less likely to become clogged with dust because it does not suck up dust from the atmosphere except when necessary.

In addition, since the air used for descending inside the cylinder is reused for discharging chips and dirt, there is no need for a silencer for discharging the air used for descending. Since there is no need to take exhaust air from the compressor, air consumption is low and economical.

It also has fewer mechanical parts and is highly reliable (and can provide a low-cost automatic screw tightening machine).

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the front main part of an automatic screw tightening machine according to an embodiment of the present invention, Fig. 2 is a top view of the same, Fig. 3 is a bottom view of the same, and Fig. 4 shows the inlet portion of Fig. 5 is a sectional view of the main part of FIG. 1 when screw tightening is completed, FIG. 6 is an air circuit diagram of the above embodiment, FIG. 7 is an air circuit diagram of another embodiment, and FIG. is an air circuit diagram of a conventional example. 13...Cylinder, 21...Bit holder, 23...Suction pipe, 27...
...Intake port, 33...Bit, 34...
・Shoot, 35... Catcher - 143...
...Switching valve (electromagnetic valve), 45...Vacuum generator, 47...Compressor, 48,50...
·tube.

Claims (1)

[Scope of Claims] 1. In a screw vacuum suction type automatic screw tightening machine, a switching valve is provided with a suction port at the tip of a suction pipe through which a bit and a bit holder are guided so as to rotate and reciprocate, and is connected to a compressor. is connected to the suction port via a tube, and this switching valve communicates only when the cylinder and suction port are rising, blowing out the air in the cylinder used when the bit is lowered to the suction port, and when the bit is lowering, the cylinder A vacuum suction type automatic screw tightening machine characterized in that a switching valve prevents direct communication between the tube and the tube, and a vacuum generator connected to the tube sucks air from the suction port. 2. The vacuum adsorption type according to claim 1, characterized in that a cylinder and a switching valve are connected, and a vacuum generator using compressed air is connected to a tube that sends air into the cylinder to lower the bit. Automatic screw tightening machine.