JPH0340465Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a portable spot welding machine that can be carried around.

<Prior art> Electrodes are provided at the tips of a pair of operating rods that are pivotally connected on the inside by a support shaft, and a driving main cylinder is interposed between the other ends of the pair of operating rods. A portable spot welding machine is known in which the distance between the electrode pairs is controlled by the expansion and contraction of the piston rod of the main cylinder.

This kind of known structure generally controls the movement of the electrode pair to two positions, an open position and a contact position through the object to be welded, by the operation of the drive cylinder.

By the way, when accurately welding a required location on a workpiece, there may be various shields around the contact position, and in order to avoid this and place the electrode, it is necessary to use a pair of electrodes. It is necessary to straddle the shield at a distance, which requires a considerable stroke. However, as for the other requirement, since the electrode pair is suddenly moved in the approaching direction by controlling the cylinder, the distance between the electrodes is as follows.
It is desirable that the distance be so small that the welding point can be properly targeted visually.

From this, it is preferable that the electrodes be capable of setting two types of separated positions at any time.

<Problems to be Solved by the Invention> In order to easily achieve these two types of separated position setting, the present applicant has proposed the one disclosed in Japanese Utility Model Application No. 62-56285.

This one, as disclosed in Figure 5,
Inside the cylinder c, which is pivotally supported by one operating rod a,
A first piston e in the shape of a cylinder with a bottom is housed therein, and a second piston g is connected to a piston rod f pivotally supported by the other operating rod b.
A first variable chamber h is provided between the first piston e and the bottom wall of the cylinder c, a second variable chamber i is provided between the first piston e and the second piston g, and a second variable chamber i is provided between the first piston e and the second piston g. A third variable chamber j is formed between the ceiling walls of the third variable chamber j, and each of the variable chambers is communicated with a pressure source via a pressure control mechanism.

By controlling the supply of pressurized fluid (air, oil) to each of the chambers, it is possible to control the position of the electrode pair in the following three ways.

That is, by releasing the pressurization in the first variable chamber h and the second variable chamber i and supplying pressurized fluid to the third variable chamber j, the first piston e is brought into pressure contact with the bottom wall of the cylinder c. , further within the first piston e, the second piston g is pressed against the main wall of the first piston e.
Therefore, the piston rod is in its most contracted state, and the electrode pair is in its maximum separated position.

Additionally, pressurized fluid is supplied to the first variable chamber h, the pressurization in the second variable chamber i is released, and the pressure in the third variable chamber j is made lower than the pressure in the first variable chamber h. As a result, the first piston e comes into pressure contact with the top wall of the cylinder c, and the second piston g comes into pressure contact with the main wall of the first piston e due to the internal pressure of the third variable chamber j. Therefore, the electrode pair is brought closer together but still at an intermediately spaced position with a gap between them.

Furthermore, by supplying pressurized fluid to the first variable chamber h and the second variable chamber i and releasing the pressurization in the third variable chamber j, the first piston e comes into pressure contact with the ceiling wall of the cylinder c, and The piston is biased toward the top wall of the main cylinder. Therefore, the electrode pair can move in the approaching direction and come into pressure contact with the object to be welded between the electrode pair.

That is, by controlling the pressure in each chamber described above,
The electrode pair is optionally converted into a maximum separation position, an intermediate separation position, and a contact position.

By the way, in such a configuration, when moving from the maximum separation position to the intermediate separation position, the pressure fluid in the third variable chamber j is removed due to the pressure difference between the first variable chamber h and the third variable chamber j. The moving speed is slow and work efficiency is poor.

Incidentally, if the third variable chamber j is opened to the atmosphere side in such a configuration, the speed can be applied rapidly, but this time, the piston loses its hold due to the pressure of the third variable chamber j, It becomes movable, and movement control from the intermediate stop position to the pressure contact position becomes impossible.
They will simultaneously move to the pressure welding position, which will destroy the meaning of the above-mentioned configuration that enabled the two-step movement, and will result in damage to the workpiece.

For this reason, it is necessary to communicate moderately pressurized air into the third variable chamber j to generate a braking action, which inevitably causes a slow movement from the maximum separation position to the intermediate separation position. Become.

The object of the present invention is to provide a configuration that can rapidly transition from a maximum separation position to an intermediate separation position.

<Means for solving the problem> The present invention has an idler cylinder housed in a main cylinder that is pivotally supported by one operating lever, and a floating cylinder that is further supported within the idler cylinder and that is pivotally supported by the other operating lever. A piston connected to the rod is disposed, a first variable chamber is provided between the floating cylinder and the bottom wall of the cylinder, a second variable chamber is defined between the floating bottom wall and the piston in the floating cylinder, and a second variable chamber is provided between the floating cylinder and the floating bottom wall. A third variable chamber is formed between the top walls of the cylinder, and a fourth variable chamber is formed between the top walls of the floating cylinder and the main cylinder, respectively, and the first to fourth variable chambers are controlled by a pressure control mechanism,
Each of the first and fourth variable chambers is configured to communicate with a pressure source, and when one of the first and fourth variable chambers communicates with the pressure source, the other is controlled to be in an open state by a switching valve of the pressure control mechanism. It is characterized by the following.

<Function> By controlling the supply of pressurized fluid (air, oil) to each of the chambers, the position of the electrode pair can be controlled in the following three ways.

a Switch the switching valve to open the first variable chamber to the atmosphere, communicate the air source to the fourth variable chamber, press the floating cylinder against the bottom wall of the main cylinder, and pressurize the third variable chamber. Fluid is applied to bring the piston into contact with the bottom wall of the floating cylinder. As a result, the piston rod is in its most contracted state, and the electrode pair is in its maximum separated position.

b By switching the switching valve to open the fourth variable chamber to the atmosphere and communicate the air source to the first variable chamber, the floating cylinder is rapidly brought into pressure contact with the top wall of the main cylinder.

Therefore, although the electrode pair approaches each other, they are still in an intermediate spaced position with a gap between them.

c By supplying pressurized fluid to the second variable chamber and releasing the pressurization in the third variable chamber, the piston is urged within the floating cylinder toward the top wall of the floating cylinder. Therefore, the electrode pair can move in the approaching direction and come into pressure contact with the object to be welded between the electrode pair.

That is, by controlling the pressure in each chamber as described above, the electrode pair is arbitrarily exchanged between a maximum separation position, an intermediate separation position, and a contact position.

<Example> An example of the present invention will be described with reference to the accompanying drawings.

In the figure, reference numerals 1a and 1b denote a pair of operating rods, which are swingably connected by a support shaft 3 that pivotally supports the ends of connecting rods 2, 2 protruding inwardly in an overlapping manner. Electrodes 4, 4 protrude inward at a substantially right angle from the tips of the operating rods 1a, 1b, so that when the tips of the operating rods 1a, 1b approach, the tips can come into contact with each other.

At the rear of the support shaft 3, the operating rods 1a,
1b, an air cylinder device 10 according to the main part of the present invention is disposed.

The configuration of the air cylinder device 10 will be explained with reference to FIG. 4.

The main cylinder 11 of the air cylinder device 10 is pivotally supported by a shaft 12 inside the rear part of one operating rod 1b, and a top wall 11a is attached to the open end of the main cylinder 11. , forming a sealed mounting chamber inside thereof. Inside the main cylinder 11 is a closed floating cylinder 15.
is stored.

A piston 18 is housed in the floating cylinder 15, and a piston rod 19 is inserted into a top wall 15a formed by a cover plate, and as the rod 19 moves, the top wall 15a and bottom wall 15b
It is possible to slide between the two. Said floating cylinder 1
5. Piston rings 20 and 21 are fitted onto the outer circumferential surface of the piston 18 to enable tight fitting and sliding movement between the piston rings 20 and 21.

The piston rod 19 also passes through the top wall 11a of the main cylinder 11 and is swingably connected to the inside of the operating rod 1a by a shaft 25. A shaft sealing member 26 is attached to the center of the top wall 11a, through which the piston rod 19 passes, and which is in close contact with the outer peripheral surface of the piston rod 19, thereby allowing the piston rod 19 to slide.

In this configuration, a first variable chamber 30 is provided between the bottom wall 11b of the main cylinder 11 and the bottom wall 15b of the floating cylinder 15, and a second variable chamber 31 is provided within the floating cylinder 15 between the bottom wall 15b and the piston 18. , a third variable chamber 32 is located between the piston 18 and the ceiling wall 15a,
Further, a fourth variable chamber 33 is formed between the floating cylinder 15 and the top wall 11a of the main cylinder 11, respectively.

The first variable chamber 30 communicates with an air supply port 34 formed in the bottom wall 11a of the main cylinder 11,
The fourth variable chamber 33 communicates with an air supply port 35 formed in the ceiling wall 11a, and
4 and 35 are respectively connected to the two-way switching solenoid valve _V1 of the pressure control mechanism C, so that when one is in communication with the air source S, the other is opened to the atmosphere.
Furthermore, air supply passages 36 and 37 are formed in the center of the piston rod 19 along its axial direction, and the outlet end of the air supply passage 36 is connected to the second variable chamber 31.
The outlet end of the air supply path 37 is communicated with the third variable chamber 32 side. Also, air supply path 3
6 and 37 form air supply ports 38 and 39 on the side surfaces of the piston rod 19, respectively. The air supply ports 38 and 39 are each connected to a two-way switching solenoid valve _V2 of the pressure control mechanism C, so that when one is in communication with the air source S, the other is opened to the atmosphere.

The operation of the apparatus of the embodiment will be explained.

As shown in FIG. 1, the solenoid is switched to operate the solenoid valves V ₁ and V ₂ to open the first variable chamber 30 to the atmosphere and connect the fourth variable chamber 33 to the air source S. Furthermore, by opening the second variable chamber 31 to the atmosphere and communicating the third variable chamber 32 to the air source S, the floating cylinder 15 is connected to the main cylinder 11.
The piston 18 comes into pressure contact with the bottom wall 15b inside the floating cylinder 15. In this state, the piston rod 19 is in its most contracted state, and the electrode pair 4, 4 is in its maximum separated position. Therefore, electrode pairs 4, 4 are placed in front and behind the required welding position, straddling the shield around the object to be welded X.

Next, as shown in FIG. 2, the solenoid valve _V1 is switched to communicate the first variable chamber 30 with the air source S from the air supply port 34, and communicate the fourth variable chamber 33 with the atmosphere. As a result, the floating cylinder 15 moves rapidly, and its top wall 15a comes into pressure contact with the top wall 11a of the main cylinder 11.

In this state, the operating rod 1a is tilted about the support shaft 3, and the electrode pair 4, 4 rapidly approaches each other, but is at an intermediate separated position where there is still a gap.

Furthermore, visually aim the electrode pair 4, 4 at the required welding position on _the workpiece
to connect the third variable chamber 32 to the atmosphere side,
The second variable chamber 31 is communicated with an air source S to supply air, and the piston 18 is connected to the top wall 11 of the cylinder 11.
Force it toward the a side.

Therefore, as shown in FIG. 3, the operating rod 1a further tilts around the support shaft 3, and the electrode pairs 4, 4 move in the approaching direction and are pressed into contact with the workpiece X, respectively.

In addition, the second variable chamber 31 and the third variable chamber 32 are
By controlling the respective pressures differently and allowing the piston 18 to move based on the pressure difference, air will not be rapidly removed from the third variable chamber 32.
The electrode pair 4, 4 can be moved gently, and the electrode pair 4, 4 can be brought into pressure contact with the object to be welded X quietly.

After setting this pressure contact position, the operating rod 1a,
Electricity is supplied to the electrode pair 4, 4 from a conductive path (not shown) in 1b, and spot welding is performed.

After the welding work is completed, the solenoid valve V ₁ and the solenoid valve V ₂ are switched to open the first variable chamber 30 and the second variable chamber 31, and to open the third variable chamber 32 and the fourth variable chamber 33.
The air source S is communicated to move the floating cylinder 15, and the piston 18 is brought into pressure contact with the bottom wall 15b of the floating cylinder 15, thereby returning the electrode pair 4, 4 to the maximum separation position.

By controlling the internal pressure of each chamber with the pressure control mechanism C, the electrode pairs 4, 4 can be changed to the maximum separation position, the intermediate separation position, and the contact position at will.

<Effects of the invention> As described above, the present invention allows communication between the first variable chamber and the fourth variable chamber to be switched to the atmosphere side or the air source S side using a switching valve, and to set the maximum separation position and the intermediate separation position. Since the reciprocal movement between the positions can be performed rapidly, there are excellent effects such as the ability to perform welding work quickly.

[Brief explanation of the drawing]

The accompanying drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional plan view showing the maximum separation position, FIG. 2 is a longitudinal sectional plan view showing the intermediate separation position, FIG. 3 is a longitudinal sectional plan view showing the contact position, and FIG. Figure 4 shows the air cylinder device 10.
FIG. Further, FIG. 5 is a cross-sectional plan view of a conventional portable spot welding machine. 1a, 1b; operating rod, 4, 4; electrode pair, 10;
Main cylinder device, 11; Main cylinder, 11
a; top wall, 11b; bottom wall, 15; floating cylinder, 18; piston, 19; piston rod, 3
0; First variable chamber, 31; Second variable chamber, 32; Third variable chamber, 34; Fourth variable chamber, 36, 37; Air supply path, V ₁ , V ₂ ; Solenoid valve, C; Pressure control mechanism,
S: Air source.

Claims (1)

[Claims for Utility Model Registration] 1. Electrodes are provided at the tips of a pair of operating rods that are pivotally connected on the inside by a support shaft, and a drive cylinder is interposed between the other ends of the pair of operating rods. The electrode pair is controlled to move away from each other by the expansion and contraction operation of the piston rod of the drive cylinder, and the floating cylinder is housed in a main cylinder pivotally supported by one of the operating rods, and the floating cylinder is A first variable chamber is formed between the floating cylinder and the bottom wall of the cylinder by disposing a piston connected to a rod pivotally supported on the other operating rod in the cylinder.
In the floating cylinder, a second variable chamber is provided between the floating bottom wall and the piston, a third variable chamber is provided between the piston and the top wall of the floating cylinder, and a fourth variable chamber is provided between the floating cylinder and the top wall of the main cylinder. are formed respectively, and the first to fourth variable chambers are controlled via a pressure control mechanism.
The first and fourth variable chambers are connected to respective pressure sources, and the first and fourth variable chambers are controlled by switching valves of a pressure control mechanism.
A portable spot welding machine characterized in that when one of the welding parts is connected to a pressure source, the other part is controlled to be in an open state. 2. Claim No. 2 of the utility model registration, characterized in that the piston rod is provided with a pressure fluid supply passage communicating with the second variable chamber and a pressure fluid supply passage communicating with the third variable chamber. Portable spot welding machine according to item 1.