GB2196493A

GB2196493A - Welding control

Info

Publication number: GB2196493A
Application number: GB08723806A
Authority: GB
Inventors: Calum Edward Medine
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-10-17
Filing date: 1987-10-09
Publication date: 1988-04-27
Also published as: GB8624947D0; GB8723806D0

Abstract

A welding control comprises a current control device 12 driven by an electric motor 2. A hand-held or foot-operated switch 4 allows an operator to operate the motor 2 and hence vary the welding current by operation of the control device 12 while continuing the welding operation. The control 12 may be a device that is remote from the welding supply 7 and normally operated manually. In an alternative embodiment, the welding torch (28), (Fig. 3) carries a three-way rocker switch (29) to control a motor (22) which adjusts a variable resistor (26) controlling the welding current, the motor (22) also operates a limit switch (25) which controls a high frequency unit 24. <IMAGE>

Description

SPECIFICATION Welding control This invention relates to a welding control.

The invention has particular application in the control of current during arc welding operations.

During an arc welding operation an operator may wish to vary the current supplied to the welding torch, for example, to take account of differing weld conditions. At present, if an operator is working alone he must stop the welding operation to adjust the current supply control as both his hands are occupied when welding, one holding the welding torch and the other holding the welding rod. Therefore, adjustment of the current in this situation may lead to undesirable discontinuity in a weld.

It is an object of this invention to obviate or mitigate this disadvantage.

According to the present invention there is provided a welding control comprising a current control device for varying welding current during operation of an electric arc welding plant, motor means for driving the current control device to vary the welding current and control means for operating the motor means, the control means being arranged to be operable by an operator engaged in a welding operation.

Preferably, the motor means is in the form of an electric motor.

Preferably also the control means for operating the motor is in the form of a switch which may be fixed to, or held in, the hand of the operator. Alternatively the control means may be in the form of a switch provided on a welding torch.

The invention is particularly suited for with Tungsten inert gas (T.l.G.) welding plant.

Embodiments of the present invention will now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic representation of a first embodiment of a welding control in accordance with the present invention; Figure 2 is a schematic representation of the welding control of Fig. 1 and welding plant and Figure 3 is a schematic representation of a second embodiment of a welding control in accordance with the present invention.

Referring to Figs. 1 and 2 of the drawings, a welding control, shown generally at 1, comprises an electric motor 2 which is connected to a 110 Volts electric power supply 3 and is controlled by means of compact switch 4.

The switch 4 is, in use, held in the hand of an operator, and can be used to cause the motor to rotate in either direction. and is controlled by means of compact switch 4. The switch 4 is, in use, held in the hand of an operator, and can be used to cause the motor to rotate in either direction.

The control 1 is used in conjunction with a welding plant, shown generally at 5, which comprises a T.l.G. welding torch 6 which is connected to one pole of an output from a transformer unit 7, and a connecting wire 8 which leads from the opposite pole of the unit 7 to a workpiece 9. Weld material 10 is supplied by means of a welding rod 11. A manually operable control 12 is linked to the unit 7 and may be used to alter the current to #the welding torch 6 and the connecting wire 8.

When an operator is welding and wishes to alter the current it is necessary for the operator to stop welding to free one of his hands to operate the control 12. However, the control unit 1 may be fitted to the plant such that an output shaft 13 from the motor 2 engages the control 12.

This permits the operator to alter the current by operating the switch 4 with the little and ring fingers of one hand while holding the welding rod 11 with the thumb and two other fingers. Thus, the operator may continue welding while adjusting the current.

Modifications and improvements may be made to the basic system such as for example, the use of a foot operated switch to control the motor.

The apparatus thus provides a simple means of varying the welding current which may be easily incorporated into a system at manufacture or produced as an add on for existing systems.

Referring now to Fig. 3 of the drawings a second embodiment of a welding control and welding plant, comprises a control unit 21 which houses an electric motor 22, which is connected to a power supply 23 of either 110 volts or 240 volts as appropriate, a high frequency unit 24, a cam operated limit switch 25 and a variable resistor 26.

The control unit 21 is used in conjunction with a welding plant which comprises a transformer unit 27 and a T.l.G. welding torch 28.

In this embodiment a three way rocker switch 29, which provides control of the motor 22, is included on the welding torch 28.

The torch 28 is connected to one pole of an output from the control unit 21. A connecting wire 8 leads from the opposite pole of the control unit 21 to a workpiece 9 where weld material 10 is supplied by means of a welding rod 11.

The rocker switch 29 permits control of the electric motor 22, and thus the operating current, in a similar fasion to the switch 4 described previously. The motor 22 has an output shaft 30 which engages the resistor 26.

The rocker switch 29 can be easily controlled by the thumb of the hand of the operator which holds the welding torch 28.

Operation of the rocker switch 29 in a first direction causes the electric motor 22 to rotate in a first direction to drive the variable resistor 26 to decrease its resistance and thus increase the welding current. Operation of the rocker switch 29 in a second direction causes the motor 22 to rotate in an opposite direction thus increasing the resistance of the variable resistor 26 and decreasing the welding current. The motor 22 also drives the limit switch 25 which controls the high frequency unit 24.

Modifications and improvements may be incorporated without departing from the scope of the invention. For example the power supply 23 may be derived direct from the transformer unit 27. The cam operated limit switch 25 may be replaced by a rotary switch connected direct to the motor and the variable resistor 26 may act as an on/off switch for the high frequency unit 24 replacing the cam operated limit switch.

Claims

1. A welding control comprising a current control device for varying welding current during operation of an electric arc welding plant, motor means for driving the current control device to vary the welding current and control means for operating the motor means, the control means being arranged to be operable by an operator engaged in a welding operation.

2. A welding control as claimed in Claim 1, wherein the motor means comprises an electric motor.

3. A welding control as claimed in Claim 1 or 2, wherein the control means for operating the motor comprises switch means which may be held in the hand of the operator.

4. A welding control as claimed in Claim 1 or 2 wherein the control means for operating the motor comprises switch means provided on a welding torch.

5. Electric arc welding apparatus incorporating a welding control as claimed in any one of the preceding claims.

6. A welding control substantially as hereinbefore described with reference to and as shown in Figs. 1 and 2 or Fig. 3 of the accompanying drawings.

7. Electric arc welding apparatus substantially as hereinbefore described with reference to and as shown in Figs. 1 and 2 or Fig. 3 of the accompanying drawings.