JPH09174248A - Portable spot welding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to rapidly execute resetting from the max. parting position to the min. parting position of an electrode pair. SOLUTION: A pressure control mechanism is constituted to have a stroke selector valve A and an operation selector valve B. This stroke selector valve A is selectively changed in positions to three positions; a first position (a) where a first variable chamber 30 is communicated with the atm. and a third variable chamber 32 is communicated with a pressure source, a second position (b) where the first variable chamber 30 is communicated with the pressure source and the third variable chamber 32 is made communicable with the pressure source and a third position (c) where the first variable chamber 30 is communicated with the pressure source and the third variable chamber 32 is communicated with the amt. Further, the operation selector valve B is selectively changed in positions to two positions; a first position where a second variable chamber is communicated with the atm. and the third variable chamber 32 is communicated with the pressure source and a second position where the second variable chamber is communicated with the pressure source and the third variable chamber 32 is communicated with the atm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable spot welder that can be carried around.

[0002]

2. Description of the Related Art As shown in FIG. 8, a pair of electrodes 4 and 4 is provided, and a cylinder-shaped first piston 15 having a bottom is housed in the cylinder 11. The second piston 18 connected to the rod 24 is disposed, the first variable chamber 30 is provided between the first piston 15 and the bottom wall of the cylinder 11, and the second variable chamber 30 is provided between the first piston 15 and the second piston 18. 31, the second piston 18 and the cylinder 1
A third variable chamber 32 is formed between the ceiling walls of No. 1 and each variable chamber 3
The cylinder device 10 capable of controlling the pressure of 0, 31, 32 via a pressure control mechanism is provided, and the piston rod 24
A portable spot welding machine is known in which the electrode pair is relatively moved in the close-up direction by using the relative displacement between the cylinder 11 and the cylinder 11 as a drive source, and the object to be welded is welded at the closest position. . As this configuration, as shown in the same figure, in addition to a configuration in which a pair of operating rods 1a and 1b are swingably connected by a support shaft 3, a fixed electrode and a moving electrode are arranged in opposition on the moving line of the moving electrode. There is also a configuration in which a fixed electrode is provided at the rod end of the air cylinder device (see FIG. 7).

In such a structure, the position control of the electrode pairs in the following three modes can be performed by controlling the supply of the pressurized air in each chamber. a) By releasing the pressurization in the first variable chamber 30 and the second variable chamber 31 and supplying pressurized air to the third variable chamber 32,
The first piston 15 is in pressure contact with the bottom wall of the cylinder 11, and within the first piston 15, the second piston 18 is in pressure contact with the main wall of the first piston 15. Therefore, the piston rod 24 is in the most contracted state, and the electrode pairs 4 and 4 are in the maximum separated position.

B) supplying pressurized air to the first variable chamber 30,
The pressurization in the second variable chamber 31 is released, and the third variable chamber 3 is further released.
By making the pressure in 2 lower than that in the first variable chamber 31, the first piston 15 is brought into pressure contact with the ceiling wall of the cylinder 11, and the second piston 18 is caused by the internal pressure in the third variable chamber 32.
It is pressed against the main wall of the first piston 15. For this reason, the electrode pairs 4 and 4 are close to each other, but are in a small separation position in which a gap is still held.

C) By supplying pressurized air to the first variable chamber 30 and the second variable chamber 31 and releasing the pressure in the third variable chamber 32, the first piston 15 is pressed against the ceiling wall of the cylinder 11. And the second piston 18 is the cylinder 1
It is urged to the top wall side of 1. Therefore, the electrode pairs 4 and 4 move in the approaching direction and can be pressed against the object to be welded between the electrode pairs 4 and 4.

That is, by controlling the pressure in each chamber, the electrode pairs 4 and 4 are arbitrarily converted into the maximum separated position, the small separated position, and the contact position. Therefore, in such a configuration, by controlling the pressure to the cylinder device 10, the electrode pairs 4 and 4 can be arbitrarily converted into the maximum separated position, the intermediate position, and the contact position. Advantages such as the ability to easily straddle the shield around the object to be welded, and the small distance position setting allows the operator to visually and safely set the electrode at the required welding position. There is.

[0007]

By the way, in such a structure, the pressure control mechanism shown in FIG. 8 is provided. As shown in FIG. 10, this pressure control mechanism selectively converts the position of the first variable chamber 30 into a first position B that communicates with the atmosphere and a second position B that communicates high pressure with the first variable chamber 30. comprising a stroke changeover valve V ₁ being, further, a second variable chamber 31 communicates with the atmosphere, a first position I of the low pressure communicates with the third variable chamber 32
And the pressure source communicates with the second variable chamber 31, and the third variable chamber 32
Is provided with an operation switching valve V ₂ which is selectively converted into two positions, a second position II communicating with the atmosphere.

By the way, in such a configuration, when the electrode pairs 4 and 4 are returned from the maximum separated position to the small separated position, the stroke switching valve V ₁ is converted to the second position b. However, in this case, the first piston 15
Since it moves due to the pressure difference from the low pressure communicating with the third variable chamber 32, there is a problem in that the operation becomes slow and the welding operation cannot be smoothly performed. An object of the present invention is to eliminate the problems of the conventional configuration.

[0009]

The present invention provides a portable spot welding machine having the above-mentioned structure, wherein the pressure control mechanism communicates the first variable chamber with the atmosphere and the third variable chamber with the pressure source. A first position that enables the first variable chamber to communicate with the pressure source and a second position that allows the third variable chamber to communicate with the pressure source;
A first variable chamber communicates with a pressure source, and a third variable chamber communicates with the atmosphere through a stroke switching valve that is selectively converted into three positions, a third position, and a second variable chamber communicates with the atmosphere. The position of the third variable chamber is selectively converted into two positions, a first position communicating with the pressure source and a second position communicating the second variable chamber with the pressure source and communicating the third variable chamber with the atmosphere. And an operation switching valve.

In such a structure, when the stroke switching valve is at the first position and the operation switching valve is at the first position, the pressurization in the first variable chamber and the second variable chamber is released, and the pressure is applied to the third variable chamber. Air is supplied and the first piston presses against the bottom wall of the cylinder, and within the first piston the second piston presses against the main wall of the first piston. Therefore, the piston rod is in the most contracted state, and the electrode pair is in the maximum separated position.

At this maximum separation position, when the stroke switching valve is set to the third position, pressurized air is supplied to the first variable chamber,
The third variable chamber communicates with the atmosphere, and the first piston abruptly comes into pressure contact with the top wall of the cylinder, and the electrode pair is brought into an approaching state.
At this time, the operation switching valve is in the first position, and therefore,
Since the second variable chamber also communicates with the atmosphere, the electrode pair is close to each other, but is in a small separation position where a gap is still held.

Next, the stroke switching valve is set to the second position,
When the operation switching valve is switched while the first piston is in pressure contact with the top wall of the cylinder, the second piston is biased toward the top wall of the cylinder in the second position. For this reason, the electrode pair moves in the approaching direction, comes into pressure contact with the object to be welded between the electrode pair, and welding becomes possible.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the accompanying drawings. In the figure, 1a and 1b are a pair of operating rods, which are swingably connected by a support shaft 3 that pivotally supports the ends of the connecting rods 2 and 2 protruding inward in a superposed manner. The tips of the operating rods 1a and 1b are provided with electrodes 4, 4 inwardly at a substantially right angle.
Of the operating rods 1a, 1b are brought into contact with each other when the tips of the operating rods 1a, 1b approach each other. An air cylinder device 10 according to the main part of the present invention is disposed between the operating rods 1a and 1b behind the support shaft 3.

The construction of the air cylinder device 10 is shown in FIG.
This will be described with reference to FIG. The cylinder 11 of the air cylinder device 10 is pivotally supported by a shaft 12 inside the rear part of one of the operating rods 1b so as to be swingable, and an open end of the cylinder 11 is covered with a ceiling wall 11a. To form a closed mounting chamber. In the cylinder 11, a bottomed cylindrical first piston 15 is housed with its main wall 15a arranged on the bottom wall 11b side of the cylinder 11.
A second piston 18 is housed in the first piston 15, and can slide between a main wall 15a and a stopper 17 formed on the inner surface of a side wall 15b of the first piston 15. The first piston 15 and the second piston 18
Piston rings 20 and 21 are fitted on the outer peripheral surfaces of the two so as to enable tight fitting sliding.

A piston rod 24 is fixed to the outer surface of the second piston 18, and the piston rod 24 is attached to the top wall 11.
It is inserted through a and is swingably connected to the inside of the operating rod 1a by a shaft 25. At the center of the ceiling wall 11a, a shaft sealing member 26, through which the piston rod 24 is inserted and which is in close contact with the outer peripheral surface thereof, is mounted so that the piston rod 24 can slide.

Due to the pistons 15 and 18, the main wall 15a of the first piston 15 and the bottom wall 11 of the cylinder 11 are provided.
The first variable chamber 30 is formed between b, the second variable chamber 31 is formed between the first piston 15 and the second piston 18, and the third variable chamber 32 is formed between the second piston 18 and the ceiling wall 11a of the cylinder 11. It

The first variable chamber 30 communicates with an air supply port 33 formed in the bottom wall 11b of the cylinder 11, and the third variable chamber 32 communicates with an air supply port 34 formed in the ceiling wall 11a. ing. Also, the piston rod 24
An air feed passage 35 is formed at the center of the piston along the axial direction thereof, the outlet end of which is formed at the central end face of the second piston 18 on the second variable chamber 31 side, and the inlet end of which is formed by the piston rod. 24 is opened on the side surface, and the air supply port 36
The air supply port 36 is communicated with the second variable chamber 31 via the air supply passage 35.

Each of the air supply ports 33, 34, 36 is connected to a pressure control mechanism, and the first variable chamber 30 and the second variable chamber 3 are connected.
1, the pressure control of the third variable chamber 32 can be performed differently.

Next, the structure of the pressure control mechanism will be described. The pressure control mechanism of the present invention is a stroke switching valve A.
And the operation switching valve B, and the pressure source P is connected to the pressure adjusting valve C.
Is connected, the operation switching valve B is connected to the pressure regulating valve side, and the stroke switching valve A is provided in front of the pressure regulating valve C.
One of the ports is connected. That is, the operation switching valve B
Communicates with the low pressure reduced by the pressure regulating valve C,
One port of the stroke switching valve A communicates with a high pressure that is not reduced by the pressure adjusting valve C. The other port of the stroke switching valve A has an operation switching valve B.
Connected to.

Next, the mechanism of the switching valves A and B will be described.
As shown in FIG. 9, the stroke switching valve A is composed of a manual switching valve that can be changed to a first position a, a second position b, and a third position c, and communicates the first variable chamber 30 with the atmosphere. The variable chamber 32 is connected via the operation switching valve B to the pressure source P whose pressure is adjusted to a low pressure by the pressure adjusting valve C, and the pressure source P is communicated to the first variable chamber 30 to make the third variable. Similarly, the second position b which allows the pressure source P whose low pressure is adjusted to communicate with the chamber 32 and the pressure source P which communicates with the first variable chamber 30
2 is selectively converted into three positions, a third position C communicating with the atmosphere.

The operation switching valve B is an electromagnetic switching valve that can be selectively switched between the first position and the second position.
To the atmosphere and the third variable chamber 32 is communicated with the low-pressure adjusted pressure source P and the first position I is communicated with the second variable chamber 31 to the low-pressure adjusted pressure source P. Is selectively converted into two positions, a second position II communicating with the atmosphere.

In such a structure, the stroke switching valve A
Is the first position a and the operation switching valve is the first position I,
The pressure in the first variable chamber 30 and the second variable chamber 31 is released,
When pressurized air is supplied to the third variable chamber 32, the first piston 15 comes into pressure contact with the bottom wall of the cylinder, and within the first piston 15, the second piston 18 comes into pressure contact with the main wall of the first piston 15. Therefore, the piston rod 24 is in the most contracted state, and the electrode pairs 4 and 4 are at the maximum separated positions in FIG.
Therefore, the electrode pairs 4 and 4 are arranged before and after the required welding position, straddling the shield around the object x to be welded.

Next, when the stroke switching valve A is set to the third position c at the maximum separated position, the pressurized air is supplied to the first variable chamber, and the inside of the third variable chamber 32 is irrespective of the operation switching valve. In communication with the atmosphere, the first piston 15 suddenly comes into pressure contact with the top wall of the cylinder, and the electrode pairs 4 and 4 rapidly approach each other. still,
At this time, the operation switching valve B is in the first position I, and therefore,
Since the second variable chamber 31 also communicates with the atmosphere, the electrode pair 4,
4 approaches, but is still in a small separation position that still has a gap.

It is possible to slowly bring the electrode pairs 4 and 4 closer to each other as in the conventional case. In this case, the stroke switching valve A is set to the second position B and the operation switching valve B is set to the first position. By setting to I, the piston 15 moves due to the differential pressure between the high pressure first variable chamber 30 and the low pressure third variable chamber 32. In such a case, the electrode pairs 4 and 4 slowly move, so that the process can be safely transferred to the next step although lacking agility. For example, it is useful when it is desired to return the electrode pairs 4 and 4 to the intermediate position while surely avoiding an obstacle. That is, in the present embodiment, the quickness of the work can be maintained by the return of the electrode pairs 4 and 4 to the swiftly small separated position, which is different from the conventional one, and the slow return may be possible depending on the situation. Will be equipped with.

Further, visually, aiming the electrode pairs 4 and 4 at the required welding position of the workpiece x, the stroke switching valve A is set to the second position B, and the first piston 15 is pressed against the top wall of the cylinder. In this state, when the operation switching valve B is switched to the second position II, the inside of the second variable chamber 31 is pressurized, the third variable chamber 32 communicates with the atmosphere, and the second piston 18 moves to the top of the cylinder. It is biased toward the wall. Therefore, as shown in FIG. 2, the operating rod 1a further tilts around the support shaft 3, the electrode pairs 4 and 4 move in the approaching direction, and each comes into pressure contact with the workpiece x. After this, a conductive path (not shown) in the operating rods 1a, 1b
To the electrode pairs 4 and 4 to perform spot welding. When changing the welding position, only the operation switching valve B is switched to the first position I. As a result, the first piston 1
In the state that 5 is pressed against the top wall of the cylinder, the third variable chamber 3
2 is pressurized, and the second variable chamber 31 communicates with the atmosphere, the second piston 18 moves in the first piston 15,
The electrode pairs 4 and 4 move in the separation direction to the small separation position shown in FIG. By this position conversion, the aim at the next welding position can be easily determined.

By controlling the internal pressure of each chamber with the pressure control mechanism, the electrode pairs 4 and 4 can be arbitrarily converted into the maximum separated position, the small separated position and the contact position.

By the way, the stroke switching valve A is manually switched by the switching lever 40 (see FIG. 1), but at least one hand must be separated from the pair of operating rods 1a and 1b, which is troublesome and force-consuming. Was required.

Therefore, in order to improve this, as shown in FIG. 4, the stroke switching valve A can be position-converted and controlled by air pressure by operating the manual pilot valves 41a and 41b using the same air source. The manual pilot valves 41a, 41b are operated by a manual switching device 42 shown in FIGS. 5 and 6, and one of the push button switches 43a, 43b provided on the manual switching device 42 is pressed to stroke control valve A. Can be moved in any one direction to be converted into any one of the first position a to the third position c.
Further, the manual switching device 42 is provided with a switch 44 for switching the operation switching valve B. The manual switching device 42 includes a grip portion 45. Therefore, by operating the manual switching device 42 with one hand, it is possible to arbitrarily perform the opening / closing operation of the electrode pairs 4 and 4 described above. . An electromagnetic valve may be applied as the stroke switching valve A. Then, the changeover switch is set to the manual changeover device 42.
May be provided.

The above-mentioned configuration is a pair of operating rods 1a, 1
The air cylinder device 10 according to the main part of the present invention has a configuration in which b is swingably connected by a support shaft 3.
Is the fixed electrode 51a and the moving electrode 5 as shown in FIG.
It is also applicable to a configuration in which the fixed electrode 51b is provided at the rod end of the air cylinder device 10 supported by the annular frame 52 so as to be opposed to 1b on the moving line of the movable electrode 51b.

Even with such a construction, the operation switching valve B can convert the moving electrode 51b between the chain line position and the position where the workpiece x is held between the fixed electrode 51a and the stroke switching valve A. This makes it possible to convert the moving electrode 51b to a position that is the maximum distance from the fixed electrode 51a in FIG. Then, the moving electrode 51 at this solid line position
In the case of returning b to the chain line position, the third variable chamber 3
The interior of 2 communicates with the atmosphere, and the first piston 15 abruptly comes into pressure contact with the top wall of the cylinder, so that the rapid movement of the movable electrode 51b is ensured.

[0031]

As described above, according to the present invention, the pressure control mechanism is provided with the stroke switching valve A and the operation switching valve B, and the stroke switching valve A is connected to the first variable chamber 30.
Communicates with the atmosphere and allows the third variable chamber 32 to communicate with the pressure source, and the first variable chamber 30 communicates with the pressure source.
The second position b that allows the third variable chamber 32 to communicate with the pressure source, and the first variable chamber 30 that communicates with the pressure source.
Is selectively converted into three positions, that is, a third position C communicating with the atmosphere, a switching valve B, a second variable chamber 31 communicating with the atmosphere, and a third variable chamber 32 a pressure source. A first position I communicating with the second variable chamber 31 communicating with a pressure source,
The position of the third variable chamber 32 is selectively changed to two positions, that is, a second position II communicating with the atmosphere.

Therefore, the electrode pairs 4, 4, 51a, 51b
When the stroke switching valve A is set to the third position c at the maximum separation position of P, the compressed air is supplied to the first variable chamber 30, and the inside of the third variable chamber 32 communicates with the atmosphere regardless of the operation switching valve B. , The electrode pairs 4, 4, 51a, 51b rapidly come close to each other, and due to the slow return of the electrode pairs as in the conventional case,
There is an excellent effect that the time until the next welding process is started becomes longer and the speed of the work is not impaired.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional side view showing a small separated position of an electrode pair of a portable spot welding machine according to the present invention.

FIG. 2 is a vertical sectional side view showing a contact position of the electrode pair of the above.

FIG. 3 is a vertical cross-sectional side view showing the maximum separated position of the above electrode pair.

FIG. 4 is a side view of a modified example including a manual switching device 42.

5 is a side view of the manual switching device 42. FIG.

FIG. 6 is a front view of a manual switching device 42.

FIG. 7 is a side view of a portable spot welding machine according to another configuration.

FIG. 8 is a side view of a portable spot welding machine having a conventional configuration.

FIG. 9 is a valve opening / closing diagram of the present invention.

FIG. 10 is a valve opening / closing diagram of a conventional configuration.

[Explanation of symbols]

 1a, 1b Operating rod 10 Cylinder device 12 Cylinder 15 First piston 18 Second piston 24 Piston rod 30 First variable chamber 31 Second variable chamber 32 Third variable chamber 41a, 41b Manual pilot valve 42 Manual switching device A Stroke switching valve B operation switching valve C pressure adjustment valve

Claims (2)

[Claims] 1. A pair of electrodes, a cylindrical bottomed first piston is housed in a cylinder, and a second piston connected to a piston rod is arranged in the first piston. , A first variable chamber between the first piston and the bottom wall of the cylinder, a second variable chamber between the first piston and the second piston,
A third variable chamber is formed between the second piston and the top wall of the cylinder, and the cylinder device is provided with the pressure in each variable chamber controllable via a pressure control mechanism, and the relative displacement between the piston rod and the cylinder. In a portable spot welding machine in which the electrode pair is relatively moved in the close-up direction by using as a driving source, the pressure control mechanism can communicate the first variable chamber with the atmosphere and the third variable chamber with the pressure source. To communicate the first position and the first variable chamber with the pressure source,
The position is selectively converted into three positions: a second position that allows the third variable chamber to communicate with the pressure source, and a third position that allows the first variable chamber to communicate with the pressure source and the third variable chamber communicates with the atmosphere. And a first position where the second variable chamber communicates with the atmosphere, the third variable chamber communicates with the pressure source, the second variable chamber communicates with the pressure source, and the third variable chamber communicates with the atmosphere. A portable spot welding machine, comprising: an operation switching valve whose position is selectively converted into two positions, that is, a second position and a communication position. 2. A portable spot welding machine according to claim 1, wherein the stroke switching valve is position-controlled by pneumatic pressure by operating a manual pilot valve using the same air source.