JPH0428703Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a gun cylinder for a portable spot welding gun that supplies welding current to an electrode provided at the tip of the rod through a cylinder rod. This invention relates to an air supply mechanism for a two-stage stroke type gun cylinder, which is used by changing the stroke amount between a large opening stroke and a small welding stroke.

(Prior art) Conventionally, this type of spot welding gun has a C-shaped yoke fixed to the cylinder casing, and opposing electrode parts are attached to the tip of the yoke and the tip of a cylinder rod that moves integrally with the piston of the cylinder. The long opening stroke between the opposing electrodes is controlled by fluid pressure in a working chamber separated by a large diameter first piston in the cylinder. In addition, a second piston with a small diameter is inserted into the inner diameter of the first piston, and a short welding stroke during work is controlled by fluid pressure operation to a pressurizing chamber and a return chamber separated by this second piston. Ru. The welding current necessary for welding is configured to flow between the opposing electrodes through the cylinder rod.

In this case, air is generally supplied to the pressurizing chamber from a supply path formed inside the cylinder rod or from a supply path provided in a rotation stopper rod.

(Problem to be solved by the invention) However, in the former case, it is necessary to form a cooling water passage inside the cylinder rod in order to prevent the temperature rise in the conduction passage of the cylinder rod, and it is not possible to provide an air supply passage inside the rod. This is not practical as it would make the diameter of the cylinder rod too thick. Furthermore, the latter mechanism, in which the detent guide rod is provided with an air supply path and moves parallel to the cylinder rod, cannot be recommended due to its design structure because it is difficult to ensure sufficient mechanical strength as the original detent mechanism.

(Means for Solving the Problems) Therefore, the present invention solves the above problems by providing air pistons whose tip end communicates with and is fixed to the first piston inside the cylinder casing, and whose rear end protrudes outside the cylinder casing. A technical measure has been taken in which the nozzle is arranged parallel to the cylinder rod.

(Function) According to the present invention, the air nozzle is
By providing the rod directly on the piston, it is possible to clearly distinguish between the rod rotation prevention function and the air supply function, and to maintain the mechanical strength of the rotation prevention rod without increasing the external size of the cylinder rod.

(Example) Examples of the present invention will be described below.

Reference numeral 1 denotes a cylinder casing, and 2 a large-diameter first piston having a cylindrical shape, which slides airtightly on the inner surface of the cylinder casing 1 via a seal, and is also able to move airtightly on the outer surface of the cylinder rod 3. . Working chamber A isolated by this piston 2
is formed, and the amount of opening stroke between the electrodes can be greatly changed by operating the fluid pressure of this working chamber. Reference numeral 4 denotes a second piston with a small diameter, which is integrally fixed to the cylinder rod 3 and can slide inside the first piston via a seal. C is formed, and by operating the fluid pressure into the pressurizing chamber B and the return chamber C, the working stroke amount during welding can be changed in a short period.

Reference numeral 5 denotes a rotation preventing guide rod, which is fixed to the rear part of the cylinder casing 1. Reference numeral 6 denotes a locking guide through which the rotation stopper rod 5 can move, and is fixed to the rear part of the cylinder rod protruding from the outside of the cylinder casing. 7 is an air nozzle having an air supply port 8 on the outside, the tip of which enters from the rear of the cylinder casing 1, and is connected to the first piston 2
The end cover 9 of the cylinder casing 1 is slid in parallel with the cylinder rod 3 in an airtight manner through a seal, with the rear part protruding to the outside of the cylinder casing 1. It is becoming possible to do so.

In the above configuration, the figure shows that air is supplied to the working chamber A of the cylinder casing 1, and the first piston 2
has moved to the left and changed to a working stroke. In this state, when operating the electrodes with a short stroke, when air is supplied to the pressurizing chamber A from the supply port 8 of the air nozzle 7, the second piston 4 moves to the left and pressurizes the electrodes. In addition, the air in the pressurized chamber is exhausted from the air nozzle, and the air is returned to the return chamber B.
When air is supplied from the air supply port 10, the electrode pressurized state is released. In this way, during welding, the electrode is repeatedly driven with short stroke motions to hit the welding location.

In addition, when the electrode is opened at the end of welding, the air in the working chamber A in the cylinder casing is discharged, and the air in the return chamber B is discharged.
By supplying air to the spot welding gun, the first piston 2 and the second piston 4 are returned to the right, the stroke between the electrodes is widened, and the spot welding gun is prepared for movement.

(Effects of the invention) As described above, according to the invention, by directly connecting the air nozzle from the outside of the cylinder casing to the first piston inside the cylinder, it is no longer necessary to increase the external size of the cylinder rod, which serves as the energization path, as in the past. Moreover, there is no need for design consideration to increase the strength of the rotation prevention guide rod as in the past.
Enjoy numerous effects.

[Brief explanation of drawings]

The figure is a side view including a half section showing an embodiment of the present invention. Explanation of symbols, 1... Cylinder casing, 2...
...First piston, 3... Cylinder rod, 4...
Second piston, 5... Rotation prevention guide rod, 6...
...Locking guide tool, 7...Air nozzle.

Claims (1)

[Scope of utility model registration request] a cylinder casing; a cylinder rod movable on the central axis of the cylinder casing;
a large-diameter first piston that can freely move between the outer surface of the cylinder rod and the inner surface of the cylinder casing;
A second piston with a small diameter fixed to the cylinder rod slides on the inner surface of the first piston; a guide rod for preventing rotation fixed to the rear part of the cylinder casing in parallel with the cylinder rod; and a guide rod for preventing rotation. In the spot welding gun cylinder, the air nozzle whose rear end protrudes outside the cylinder serves as an air supply path for the first piston. A portable spot welding gun/cylinder characterized by being connected to and fixed to one piston.