JP2569469Y2 - Spot welding equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spot welding apparatus.

[0002]

2. Description of the Related Art In spot welding, a back bar is used to prevent dents on a panel outer plate. The back bar and the tip need to be replaced due to electro wear due to the progress of use. In addition, the back bar must be arranged so as to be able to float in order to always make a correct surface contact with the workpiece.

In order to satisfy these requirements, Japanese Patent Laid-Open No.
No. 75786 provides a spot welding apparatus. In this spot welding apparatus, two guide shafts are fixed to a frame to which the chip is fixed in an axial direction parallel to the chip with the chip as a center, and a back provided with a square groove in which the chip is fitted to the guide shaft. The bar is guided and supported via a spring, and a nut is tightened via a spherical washer.

[0004]

In the above-mentioned conventional device, a guide portion for a guide shaft is formed on both sides of the back bar.
The portion that actually contacts the work is protruded from the guide portion, so that the guide portions on both sides of the back bar interfere with the work or the piece supporting the work, and the space in the lateral direction is limited.

[0005] Further, since the back bar is pressed in the direction of contact with the work by the spring, the work may be bent at the time of hitting.

Further, the back bar is made floatable by a spherical washer, but the floating range is limited by the difference between the hole diameter of the guide portion on both sides of the back bar and the guide shaft diameter, and the chip is formed in a square groove. Since the chips are fitted, the side surface of the chip hits the corner of the rectangular groove at the time of floating, and galling occurs. And since a tip is a point contact which contacts a plane of the bottom of a square groove by a curved surface, an energization area is small and affects welding quality.

[0007] The attachment and detachment of the back bar requires a tool for operating the nut, and since the two nuts are tightened and loosened, it takes time to attach and detach the chip. The chip cannot be replaced without removing the back bar. There are problems such as.

[0008] An object of the present invention is to provide a spot welding apparatus which solves the above-mentioned conventional problems.

[0009]

In order to achieve the above object, the present invention comprises a shank in which a tip having a spherical tip is attached to the tip, a fixing bracket which penetrates and holds the shank so as to be axially movable, and A movable bracket pivotally and pivotally attached to the fixed bracket, an arc groove in which the tip of the tip is spherically fitted, and a back bar fixed to the movable bracket; A positioning pin for positioning the movable bracket at a normal position so as to be located on the same axis as the chip at the tip position, and a positioning pin interposed between the shank and the fixed bracket to always press the chip against the arc groove of the back bar. And a compression spring.

[0010]

According to the above construction, the tip is always spherically fitted into the arc groove of the back bar by the compression spring to enlarge the energizing area, and in this state, the back bar swings in a large range around the pivot point of the movable bracket. Move. Further, when exchanging tips, the back bar can be retracted from the tip position with one touch by turning the movable bracket largely.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. 1 and 2, reference numeral 1 denotes a shank (gun shaft) to which a tip 2 having a spherical tip is attached. The shank 1 is supported by a fixed bracket 3 so as to be axially movable.

A movable bracket 4 is pivotally attached to the fixed bracket 3 by a pin 5 so as to swing and turn. A back bar 6 having an arc groove 8 into which the tip of the tip 2 is fitted spherically is fixed to the movable bracket 4 by a bolt 7.

Normally, the movable bracket 4 is fixed to the shank 1 so that the arc groove 8 is located on the same axis as the tip 2 (the shank 1) at the tip end position of the tip 2. The tip 2 is always pressed against the arc groove 8 of the back bar 6 by a compression spring 9 interposed between the bracket 3 and the compression spring 9.

The positioning mechanism of the back bar 6 is shown in FIG.
As shown in FIG. 6 and FIG.
Are fixed on both sides of the bracket 10 in axial holes 1 parallel to the pins 5 pivotally attaching the movable bracket 4.
A pair of positioning pins 12 are slidably fitted in the holes 11, and a pair of positioning pins 1
A spring 14 that constantly presses the positioning pin 12 outward is interposed between the two. Reference numeral 13 denotes a knob for the positioning pin 12.

On the other hand, the movable bracket 4 is provided with a concave groove 4a which comes into contact with the outer diameter of the positioning pin 12, and when the movable bracket 4 is located at a regular position, as shown in FIG. Swing in a required range where the concave groove 4a interferes with the pin 12 is allowed. Further, by pressing the positioning pin 12 in the direction of the depth of the hole 11, FIG.
As shown by, the positioning pin 12 moves to a position where it does not interfere with the concave groove 4a, and the movable bracket 4 enables a large swing movement about the pin 5.

Since the present invention has the structure as described above, in the normal case where spot welding is performed, as shown in FIGS. 1 and 2, the arc groove 8 of the back bar 6 The movable bracket 4 is positioned at a regular position so as to be located on the same axis as the (shank 1). As a result, the tip of the tip 2 is moved backward by the axial movement of the shank 1 being pushed by the compression spring 9 in the forward direction.
Abut on the arc groove 8 with a curved surface contact, thereby enlarging the energizing area.

As shown in FIG. 3, the swing of the back bar 6 at the time of spot welding requires a range in which the movable bracket 4 interferes with the positioning pin 12 with the concave groove 4a around the pin 5 which is the pivot point. Tolerate.

When the chip 2 is replaced, as shown in FIG. 6, by pressing the positioning pin 12 in the depth direction of the hole 11, the positioning pin 12 moves to a position where it does not interfere with the concave groove 4a and moves. As shown in FIG. 4, the bracket 4 can largely pivot around the pin 5,
The back bar 6 is avoided from the front of the chip 2, and the chip 2
Facilitates desorption. After the tip 2 has been replaced, the movable bracket 4 is turned back to the normal position, so that the tip 2
Are fitted into the arc groove 8 of the back bar 6, and are positioned at positions where the concave grooves 4a interfere with the positioning pins 12 returned by the springs 14.

When the back bar 6 is to be replaced, the movable bracket 4 can be easily replaced by detaching and attaching the bolt 7 while keeping the movable bracket 4 in the spot weldable state shown in FIG.

[0020]

As described above, according to the present invention, a shank in which a tip having a spherical tip is attached to the tip, a fixed bracket which penetrates and holds the shank so as to be axially movable, and which can swing and pivot on the fixed bracket. A movable bracket pivotally attached, an arc groove in which the tip of the tip is spherically fitted, a back bar fixed to the movable bracket, and the arc groove of the back bar being coaxial with the tip at the tip position of the tip. A positioning pin for positioning the movable bracket at a regular position so as to be positioned, and a compression spring interposed between the shank and a fixed bracket for constantly pressing the tip against the arc groove of the back bar. Therefore, the current-carrying area between the back bar and the tip is enlarged due to the curved surface contact, and since the contact is always in contact, the current resistance is reduced, There is improved. In addition, a large swing range of the back bar can be obtained, and at the time of chip replacement, the back bar can be avoided from the front of the chip with one touch, and the chip replacement operation can be performed quickly and easily.

[Brief description of the drawings]

FIG. 1 is a side view of the present invention.

FIG. 2 is a plan view of the present invention.

FIG. 3 is a side view showing a swinging state of a movable bracket.

FIG. 4 is a side view showing the pivoting movement of the movable bracket.

5 is a sectional view taken along line AA of FIG. 1 in a positioning state.

FIG. 6 is a sectional view taken along line AA of FIG. 1 in a positioning release state;

[Explanation of symbols]

 Reference Signs List 1 shank 2 tip 3 fixing bracket 4 movable bracket 4a concave groove 5 pin 6 back bar 8 arc groove 9 compression spring 10 bracket 11 hole 12 positioning pin 13 knob 14 spring

Claims (1)

(57) [Scope of request for utility model registration] 1. A shank having a tip with a spherical tip attached to the tip, a fixed bracket that penetrates and holds the shank so as to be axially movable, a movable bracket pivotally and pivotally mounted on the fixed bracket, and the tip. A back bar fixed to the movable bracket, and the movable bracket is positioned at a regular position such that the arc groove of the back bar is located on the same axis as the tip at the tip end position of the tip. And a compression spring interposed between the shank and a fixed bracket to constantly press the tip against the arc groove of the back bar.