WO1994029063A1

WO1994029063A1 - Tig welding machine

Info

Publication number: WO1994029063A1
Application number: PCT/GB1994/001196
Authority: WO
Inventors: Patrick Paul Leslie Wade
Original assignee: Wade & Hotson (Sheffield) Limited
Priority date: 1993-06-05
Filing date: 1994-06-02
Publication date: 1994-12-22
Also published as: GB9502286D0; AU6804194A; GB9311688D0; GB2284375A

Abstract

A portable, TIG welding machine comprising a guide member (1); a carriage (2) displaceable along the guide member (1) at a predetermined speed, a TIG head (15) carried by, and moveable with the carriage (2), and an automatic welding wire feed device (19-22) for feeding wire to the vicinity of the TIG head (15) at a suitable feed rate in accordance with wire consumption rate and carriage speed.

Description

TIG WELDING MACHINE

This invention relates to a TIG welding machine particularly, but not exclusively, for circumstances where welds of consistent and guaranteed high quality are required between, for example, stainless steel and mild steel. For instance, the current programme in the UK of installing flue gas desulphurisation (FGD) equipment at coal burning power stations requires the provision of a long life, protective, stainless steel lining secured by welding to the mild steel structure of the FGD equipment subject to corrosive attack. Currently, the installation of such linings is effected by hand, with attendant problems of weld quality consistency and hence in guaranteeing weld integrity, while furthermore, many installations are in awkward or overhead locations, which do not assist in attaining quality welds. A basic object of the present invention is to provide a welding machine of a portable kind which consequently can be taken on site to produce consistent, machine quality welds in FGD equipment.

According to the present invention there is provided a portable, TIG welding machine comprising a guide member; a carriage displaceable along the guide member at a predetermined speed, a TIG head carried by, and moveable with the carriage, and an automatic welding wire feed device for feeding wire to the vicinity of the TIG head at a suitable feed rate in accordance with wire consumption rate and carriage speed.

In detail, if it is required to produce a linear weld, then the guide member conveniently takes the form of a beam, typically of 2-3 metres in length to achieve portability. The beam is preferably provided with a rack engageable by a haulage pinion of the carriage whereby a power means, such as an electric motor mounted on the carriage, may drive the haulage pinion. The choice of haulage speed may be achieved by any convenient means, such as the use of a multi-speed motor or selectable gearing. For a circular weld, e.g. to produce a weld around a pipe, then the linear beam may be replaced by a rubber track.

The feed of welding wire may be effected from a spool, drivable at variable speed, with the wire passing inside a guidance tube and emerging in the vicinity of the TIG head. Preferably, the machine is provided with securing means, e.g. rubber suction feet, typically provided in pairs at spaced apart locations along the beam, to secure the machine in its required position, with vacuum means connected to the feet for overhead use. Preferably, provision is made for fine positional adjustment of the TIG head, under the control of the user. Such fine adjustment may be in two orthogonal directions, e.g. laterally of the beam and towards or away from the required weld to provide positional head accuracy once the machine has been located in position. Typically, fine adjustment may be by a rotary knob having a pinion in engagement with a rack of an arm carrying, directly or indirectly, the TIG head.

One example of machine in accordance with the invention for producing a linear weld is illustrated in the accompanying drawing, which is a perspective view of the machine, during welding.

In the drawing is illustrated a portable TIG welding machine comprising a guide member 1 in the form of a beam, and a carriage 2 slidably and drivably mounted on the guide member 1 and displaceable along the guide member 1 at a predetermined speed.

Displacement is effected by an electric motor (not shown), housed within a casing 3 of the carriage 2. The motor may be of a multi-speed kind having a haulage pinion 5 drivably engaging a central rack 4 extending along an upper surface of the guide member 1.

Externally, the casing 3 is provided with a block 6 through which slidably passes a rack 7, which is positionally adjustable with respect to the block 6, in a direction transversely of the guide member 1, by a hand wheel 8 connected by a shaft to a pinion 9 engaging the rack and being lockable and releasable by a manually operable lock screw 10. At one end the rack 7 carries a generally orthogonal block 11 through which slidably passes a rack 12, which is positionally adjustable with respect to the block 11, in a direction generally orthogonally of the rack 7 by two hand wheels 13 connected by a common shaft 14 to a pinion (not shown) engaging the rack 12. The shaft 7 is locked in position by a lockable and releasable screw 15.

A TIG head 16 is attached to an upper end of the rack 12 by a slotted link 17 with a securing nut 18. Welding wire is drivably fed, at an adjustable speed rate by means of a motor 19 and speed reduction gearbox 20 from a spool 21, along a flexible synthetic plastics guidance tube 22, to emerge from a terminal and open end 23 of the tube 22 in close proximity to the electrode 24.

At linearly spaced apart locations along the underside of the guide member 1 are attached pairs of struts 25 inter-connected by a common bar 26 to which is attached, by nuts 27, a bar 28 carrying at opposite ends a cup 29 with a rubber vacuum foot 30 and an over-centre operating lever 31.

For purposes of illustration, the machine of the drawing is shown in position for producing a linear weld 32, along two prepared and abutting edges 33, 34 of sheets or plates 35, 36 of stainless steel to be joined. The plates are laid on the floor, the machine seated by its vacuum feet 30 along an edge of one sheet 35, and is accurately adjusted to a position parallel to the required weld 32 before the levers 31 are actuated to clamp the machine in position, with the TIG head 14 approximately over the weld 32. Fine positional adjustment of the TIG head 14 is reflected by releasing the lock screw 10, rotating the hand wheel 8 to displace the rack 7 and hence the TIG head laterally of the beam 1, with the lock screw 10 re-tightened. This is repeated with the lock screw 14 and hand wheels 13. The carriage is also displaced to one end of the guide member 1, so that welding may commence. The welding wire feed speed is settable by experience and or trial and error and depends of course on the selected haulage speed for the carriage 2 and the rate of wire consumption.

It will be appreciated that the suction feet 30 enable the machine to be located on a vertical wall i.e., with the feet 30 in a common vertical plane, so that linear welds may be effected horizontally, vertically, or at any required intermediate angle. For overhead use i.e., with the machine suspended upside down by its feet 30, safety requirements might dictate the connection of a vacuum pump to the fee 30 and/or additional feet to the six feet illustrated for a linear member 1 of say 3m length.

Claims

1. A portable, TIG welding machine comprising a guide member; a carriage displaceable along the guide member at a predetermined speed, a TIG head carried by, and moveable with the carriage, and an automatic welding wire feed device for feeding wire to the vicinity of the TIG head at a suitable feed rate in accordance with wire consumption rate and carriage speed.

2. A machine as claimed in Claim 1 for the production of a linear weld, characterised in that the guide member takes the form of a beam, typically of 2-3 metres in length to achieve portability.

3. A machine as claimed in Claim 1 for the production of a circular weld, characterised in that the guide member is a track of rubber or other elastomeric material.

4. A machine as claimed in any preceding Claim characterised in that the beam is provided with a rack engageable by a haulage pinion of the carriage whereby a power means, such as an electric motor mounted on the carriage, may drive the haulage pinion.

5. A machine as claimed in Claim 4, characterised in that the power means is a multi-speed motor.

6. A machine as claimed in Claim 4 or Claim 5, characterised in that selectable gearing is interposed between the power means and the haulage pinion.

7. A machine as claimed in any preceding Claim, characterised in that the feed of welding wire is effected from a spool, drivable at variable speed, with the wire passing inside a guidance tube and emerging in the vicinity of the TIG head.

8. A machine as claimed in any preceding Claim, characterised in that the machine is provided with securing means to secure the machine in its required position.

9. A machine as claimed in Claim 8, characterised in that the securing means are rubber suction feet.

10. A machine as claimed in Claim 9, characterised in that the suction feet are provided in pairs at spaced apart locations along the beam.

11. A machine as claimed in Claim 9 or Claim 10, characterised in that vacuum means are connected to the feet.

12. A machine as claimed in any preceding Claim, characterised in that means are provided for fine positional adjustment of the TIG head, under the control of the user.

13. A machine as claimed in Claim 12, characterised in that the fine adjustment is in two orthogonal directions, e.g. laterally of the beam and towards or away from the required weld, to provide positional head accuracy once the machine has been located in position.

14. A machine as claimed in Claim 12 or Claim 13, characterised in that fine adjustment is by a rotary knob having a pinion in engagement with a rack of an arm carrying, directly or indirectly, the TIG head.