JPH0327749Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a welding gun in which a pair of gun arms are pivotally supported in a manner that they can be freely opened and closed on a pivot shaft installed horizontally between a pair of side plates constituting a gun bracket. The present invention relates to a stroke adjustment device provided to vary the opening/closing stroke of a gun arm according to the shape of a workpiece, etc.

(Prior Art) Conventionally, as seen in Japanese Utility Model Publication No. 56-26944, in this type of device, a pair of stoppers are provided on the tail end sides of a pair of gun arms, facing each other in the swinging direction of the two gun arms. In addition, a stroke regulating cam consisting of a stepped shaft is provided between the pair of side plates of the gun bracket so as to be movable in the axial direction so as to cross the opposing gap between the two stoppers, and the movement causes the two stoppers to face each other. It is known that the opening/closing stroke of the gun arm can be varied in two steps, by freely switching between a state in which the small diameter portion of the cam is exposed to the gap and a state in which the large diameter portion is exposed in the gap.

In this case, a cylinder for moving the cam is fixed to one side plate, and the end of the cam is slidably inserted into the other side plate.

(Problems to be solved by the invention) With the above, welding spatters may adhere to the insertion and insertion point of the cam on the other side plate, making it impossible to move the cam, and also preventing the cam from reciprocating. like,
The cylinder must be constructed of a relatively long double-acting cylinder with a built-in piston connected to the cam, and when the cylinder overhangs one side of the gun bracket and welding in a crowded area, the cylinder must be There is a problem that it tends to interfere with the workpiece.

An object of the present invention is to provide a stroke adjustment device that solves these problems.

(Means for Solving the Problems) In order to achieve the above object, the present invention has provided a gun bracket with a shaft mounted horizontally between a pair of side plates constituting a gun bracket.
A pair of gun arms are pivotally supported so that they can be opened and closed, and a pair of stoppers are provided on the tail end sides of both gun arms to face each other in the swinging direction of the two gun arms, and a gap between the two stoppers is crossed between the two side plates. In a device in which a stroke regulating cam consisting of a stepped shaft is movable in the axial direction thereof, a pair of cylinders opening inward and located on the same axis as the cam are fitted to the side plates. It is characterized in that both ends of the cam are fitted into both cylinders.

(Operation) By selectively supplying pressure fluid to a pair of cylinders, the cam is moved in one direction and the other in the axial direction,
The opening/closing stroke of the gun arm is switched by selectively exposing the small diameter part and the large diameter part of the cam to the opposing gap between the pair of stoppers.

Here, since both ends of the cam are fitted into each cylinder and are not exposed to the outer surface of the gun bracket, problems such as malfunction of the cam due to adhesion of welding spatters do not occur.

In addition, each cylinder can be constructed compactly by a ram-type single-acting cylinder with a ram at the end of the cam, and since each cylinder is fitted to each side plate, the length of the cylinder projecting from each side plate is It is shortened as much as possible, and there is no interference with the workpiece even when welding is performed in a crowded situation.

(Example) Referring to FIGS. 1 and 2, reference numeral 1 designates a gun bracket having a pair of side plates 1a, 1a, which is held at the tail end of the bracket 1 by the side plates 1a, 1a. At the same time as installing the transformer 2, a pivot 3 extending across the both side plates 1a, 1a is installed horizontally at the tip thereof, and a pair of gun arms 4, 4 extending forward from the pivot 3 are bolted to the tail end thereof. The arm holders 4a, 4a are pivotally supported to be openable and closable, and a pressure cylinder 5 is attached to the tail end of one of the arm holders 4a.
, connect the piston rod 5a to the other arm holder 4a, and connect both gun arms 4, 4.
The opening/closing operation by the pressurizing cylinder 5 is applied to the pressurizing cylinder 5.

Further, as shown in FIGS. 3 and 4, the two arm holders 4a, 4a are provided with a
A pair of stoppers 6, 6 are bolted together, and a large diameter portion 7a and a small diameter portion 7b are provided between the side plates 1a, 1a.
A cam 7 consisting of a stepped shaft having a stepped shaft is disposed so as to cross the opposing gap between the two stoppers 6, 6, and is located on the same axis as the cam 7 on the both side plates 1a, 1a. A pair of cylinders 8, 8 opening in the same direction are fitted, and the cam 7 is fitted into both cylinders 8, 8.
The cylinders 8 constitute a ram-type single-acting air cylinder in which the end of the cam 7 serves as a ram, and the ports 8a, 8a at the outer ends of the cylinders 8, 8 are connected to each other. By selectively supplying air through the cam 7, the large diameter portion 7
It is possible to move between a first position on the right side (the position shown in the figure) where the small diameter portion 7b faces the opposing gap and a second position on the left side where the small diameter portion 7b faces the opposing gap.

In the drawing, reference numeral 9 indicates an ounce copper plate for power supply connecting the transformer 2 and each gun arm 4.

Next, to explain the operation of the above embodiment, when the pair of gun arms 4, 4 is opened from the illustrated closed state by the contraction operation of the pressurizing cylinder 5, the pair of stoppers 6, 6 are opened.
contacts the cam 7 from both sides of its periphery, restricting the further opening movement of both the gun arms 4, 4, and thus the cam 7 is moved to the above-mentioned first position by supplying air to the cylinder 8 on the left side in FIG. Large diameter part 7a as a position
If both the stoppers 6, 6 are brought into contact with the
The opening and closing strokes of both the gun arms 4, 4 are reduced, and the cam 7 is moved to the left to the second position by supplying air to the right cylinder 8, so that the two stoppers 6, 6 come into contact with the small diameter portion 7b. This will increase the opening/closing stroke.

Here, during welding work, welding spatter may scatter and adhere to the arrangement portions of these cylinders 8, 8, but the cam 7 fitted into both cylinders 8, 8
Both ends of the cam 7 are protected from welding spatter.
No malfunction will occur.

Further, the outer ends of the cylinders 8, 8 only protrude slightly over the outer surface of each side plate 1a, and even if welding is performed in a crowded place, these cylinders 8, 8
No interference with the workpiece.

(Effects of the invention) As described above, according to the invention, it is possible to prevent malfunction of the cam due to adhesion of welding spatters, and it is also possible to shorten the length of the cylinder overhanging the gun bracket, which eliminates concerns about the cylinder interfering with the workpiece. The welding gun can be moved without any movement, which has the effect of improving work efficiency.

[Brief explanation of the drawing]

Figure 1 is a side view of an example of a welding gun equipped with the proposed device, Figure 2 is its bottom view, Figure 3 is a side view of the main parts with the gun bracket removed, and Figure 4 is Figure 3. FIG. 1...Gun bracket, 1a...Side plate, 3...
Axis, 4...Gun arm, 6...Stopper, 7...
...Cam, 8...Cylinder.

Claims (1)

[Scope of utility model registration request] A pair of gun arms are pivotally supported to be openable and closable on a pivot provided horizontally between a pair of side plates constituting a gun bracket, and a pair of stoppers are provided at the tail end sides of both gun arms, facing in the swinging direction of both gun arms. and a stroke regulating cam consisting of a stepped shaft is provided between the both side plates so as to be movable in the axial direction so as to cross the opposing gap between the two stoppers, and a cam identical to the cam is provided on the both side plates. A stroke adjusting device for a welding gun, characterized in that a pair of cylinders positioned on an axis and opening inward are fitted, and both ends of the cam are fitted into the cylinders.