JPS628933Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stroke adjusting device that can switch the opening/closing stroke of a gun arm in a welding gun into at least two steps, large and small, depending on the shape of a workpiece and the like.

As a conventional device of this kind, according to Japanese Utility Model Publication No. 56-26944, a pair of longitudinally elongated gun arms having front end electrodes on the machine frame are pivotally supported by an intermediate pivot, and both arms are connected to each other. It can be opened and closed freely by a cylinder or other pressurizing mechanism arranged on the tail end side of the machine frame, and a stroke regulating stopper is inserted between a pair of stoppers formed on the rear end side of the machine frame on opposite sides. A cam is provided, and when the front ends of the arms open, the opening position is regulated by the contact of the stoppers with the cam, and the opening/closing stroke of the arms is adjusted depending on the shape of the cam. However, in this case, both stoppers are generally provided in a position forward of the pressure mechanism, that is, closer to the pivot axis, and according to this, the stoppers are adjusted to the cam. When the pressurizing mechanism makes contact with the stopper, the pressure applied by the pressurizing mechanism is increased and acts on the stopper, which tends to cause wear and damage to the stopper and the cam, resulting in the inconvenience of impairing durability.

The object of the present invention is to provide a device that eliminates such inconveniences, and as illustrated in the drawing, a pair of gun arms 3 which are longitudinally longitudinal and have electrodes 2, 2 at the front end on a machine frame 1 are provided. . In the case where a cam 7 for stroke regulation is inserted between a pair of stoppers 6, 6 formed on opposing surfaces on the rear end side of both arms 3, 3, both stoppers 6, 6 are connected to the pressurizing mechanism 5. It is characterized by being provided in a more rearward position.

In the illustrated example, the machine frame 1 is formed in the shape of a longitudinally elongated housing, and the pivot shaft 4 is installed horizontally at the front end of the machine frame 1, and the gun arms 3, 3 are commonly attached to the pivot shaft 4. A transformer 8 is provided on the front side of the machine frame 1, and terminal plates 8a of both poles of the transformer 8 are connected to each other.
8a was connected to both arms 3, 3 via ounce copper plates 8b, 8b, respectively.

Each arm 3 is composed of front and rear halves 3a and 3b that are bolted to each other, and the rear halves 3b and 3b of both arms 3 are placed behind the transformer 8 by sandwiching the latter halves 3b and 3b. The pressurizing mechanism 5 was extended, and the pressure mechanism 5 was provided at the rear end thereof, and each stopper 6 was provided further behind it, and the cam 7 was provided at the rear end within the machine frame 1 corresponding to the stopper 6.

The pressurizing mechanism 5 has a piston rod 5b of a pressurizing cylinder 5a fixed to one gun arm 3.
The cam 7 is fixed to the other gun arm 3 through the machine frame 1, and the cam 7 is connected to the operating cylinder 9.
The cam 7 shall be composed of a rotating cam fixed to a rotating shaft 10 in the machine frame 1 which is rotated by a
A large diameter portion 7a and a small diameter portion 7b formed in the above-mentioned shape are switchably inserted between the two stoppers 6, 6 of the two arms 3, 3.

Next, to explain the operation, both gun arms 3, 3 are opened and closed by the pressurizing mechanism 5 to perform a predetermined welding. stopper 6,6
When the large diameter portion 7a of the cam 7 is located between the stoppers 6, 6, the arms 3, 3 open slightly. When the small diameter portion 7b of the cam 7 is located between the stoppers 6, the arms 3, 3 are wide open and the opening/closing stroke becomes large.

The above-mentioned operation is similar to the above-mentioned conventional one, but according to the present invention, the two stoppers 6, 6 are located at the rear side of the pressurizing mechanism 5, that is, on the side away from the pivot 4 of the two arms 3, 3. When the two stoppers 6, 6 come into contact with the cam 7, the load acting on the cam 7 is smaller than the pressing force applied by the pressing mechanism 5, and thus the two stoppers 6, 6 Also, the cam 7 is less prone to wear and damage.

As described above, according to the present invention, the stopper 6 formed on the gun arm 3 is provided at a position rearward from the pressure mechanism 5, and the distance between the stopper 6 and the front pivot 4 is longer than that of the pressure mechanism 5. The load applied when the stopper 6 contacts the cam 7 is smaller than the pressing force of the pressing mechanism 5, which has the effect of improving the durability of the stopper 6 and the cam 7.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view of an example of the device of the present invention;
FIG. 2 is a cross-sectional plan view taken along the line -- in FIG. 1. 1... Machine frame, 2... Electrode, 3... Gun arm,
4... Pivot, 5... Pressure mechanism, 6... Stopper,
7...Cam.

Claims (1)

[Scope of utility model registration request] A pair of longitudinally longitudinal gun arms 3, 3 having front end electrodes 2, 2 are pivotally supported by a pivot shaft 4 in the middle of the machine frame 1. It can be opened and closed freely by a pressure mechanism 5 provided on the rear end side, and both arms 3, 3 are attached to the machine frame 1.
A pair of stoppers 6 formed on opposing surfaces on the rear end side,
6. A stroke adjusting device for a welding gun, characterized in that a stroke regulating cam 7 inserted between two stoppers 6 and 6 is provided at a position rearward of the pressurizing mechanism 5.