DE300536C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

PATENT LETTERING

VI 300536 CLASS 21 h. GROUP

The common spot welding machines show a limited arm or radius Welding levers, generally no more than 300 to 500 mm. With the small ones in question Voltage of 2 to 3 volts, the cross-sections of the arms would have to be very large with a longer extension to avoid impermissible line loss to prevent. The weight of such large arms would then be too great in view of the fact that the Arms are only attached at one end and the heavy lever at the free floating end the pressure required for welding of 75 to 100 kg and more can be withstood

got to. The gear ratio of the pedal by means of which the pressure is applied becomes more unfavorable with increasing arm length, accordingly the necessary one also grows Pressure on the foot lever and its stroke, since it has to protrude further, is higher.

These circumstances make it difficult to work on such spot welding machines with long Poor. The same is true when the arms. instead of spot welding electrodes with roller electrodes are provided for a continuous seam.

At the moment one helps oneself with the hollow bodies to be welded, in particular pipes, of greater welding length than the normal arm extension, from both ends from inserting into the arms and thus achieves a seam twice the length of the arm extension.

But this is only a makeshift and a cumbersome job. In addition, this is sufficient double extension of ordinary arms usually not yet, because it only corresponds to one Seam length from 0.60 to im. However, pipes are prepared in lengths of 2 to 3 m and more.

About the evils which are more unusual with the use of strong arms We have made the following arrangement.

Two welding transformers i, 2 for point or Roller welding are placed against each other with their arms 3, 4 and the latter designed as continuous parts. Because the arms are supported in this way at both ends and free ends are omitted, they can be made as thick as desired.

The forearm 4, over which the pipe to be welded is to be inserted, is at one end 6 rotatably mounted, at the other end 7 by screwing or otherwise as simple as possible Wise held while maintaining good contact.

The spot welding device 8 is attached to the upper arm 3 by means of a lever 11 through a spur gear 9 to move along a rack 10. Knee lever 12 is used to carry out the weld. In practice, levers 11 and 12 can also be combined in such a way that when they are lifted of the toggle lever the device moves forward.

When using the roller welding device 13, this is carried out on the spindle 14

the handwheels 15, 16 or at their Position moved forward by mechanical drive.

The two welding transformers 1/2 are connected in parallel, and their current output to respective welding point or to the respective seam welding line is distributed in proportion the distance to the latter and results in equal currents at all points. In the middle of the arm, both transformers will be equally loaded when welding.

With this arrangement, the arm length and thus also the seam length are very wide Limits are set, and the usual pipe lengths of up to 3 m, even more, can be used in. one Gang be welded point by point or seam.

Claims (1)

Patent claim: Device for electric welding of long hollow bodies, in particular pipes, characterized by the arrangement of a welding transformer at each end of the welding arms supported at both ends. 1 sheet of drawings.