NZ247529A - Structural hollow section longitudinal seam welding apparatus - Google Patents

Description

*47 32 NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION r p? ; Ua : J 2! NO N CO -a > H © 3 CO o CO n 8 AFTER PROVISIONAL NO: 247529 DATED: 30 APRIL 1993 IMPROVEMENTS IN AND RELATING TO WELDING WE, FLETCHER CHALLENGE LIMITED, of 810 Great South Road, Penrose, Auckland, New Zealand, a New Zealand company, hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: 247 529 BACKGROUND OF THE INVENTION This invention relates to improvements in and relating to welding.

More particularly, the present invention relates to apparatus and methods for the welding of metal poles, especially but not exclusively metal poles which are tapered.

The use of metal poles rather than wooden poles for a variety of purposes is well accepted particularly in climates and environments where wooden poles can deteriorate quite rapidly due to weather or insect attack. A further important reason is in respect of road safety, a metal pole being able to absorb the force of an impact by a vehicle and make it less likely that the vehicle's occupants will be injured.

In one particular use, metal poles have been replacing wooden poles for use as lamp posts for example.

In the production of elongate metal poles, typically a length of metal sheet of suitable thickness will be folded over so as to form a hollow section pole with the adjacent edges then being tack welded together. 247529 The use of tack welding has various disadvantages including the quality of the finished product both in appearance and strength and also the fact that it is a manual operation requiring the employment of a welder.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a method and/or apparatus for welding an elongate metal item in a speedy and effective manner or which at least will provide the public with a useful choice.

Further objects of the invention will become apparent from the following description.

BRIEF SUMMARY OF THE INVENTION According to one aspect of the present invention there is provided a method of welding an elongate metal item along a pair of adjacent edges, said method comprising: i) Providing a controlled feed of said item into a welding assembly; ii) Applying pressure about said metal item as it travels through said welding assembly so as to obtain a required positioning of said edges 247 529 - 4 Si ¥ tC5 cn cn T- Q il) > iTi 21 UJ < i 0. : CD oo iu X relative one with the other; iii) Providing a welding means activated when said edges are presented thereto; iv) Providing a temperature compensation for a side of said item opposite the said edges to reduce bending of the item after welding; and v) Providing feed means to receive and transport said item after welding, out of said welding assembly. According to a further aspect of the present invention there is provided a welding apparatus for carrying out the above defined method.

According to a still further aspect of the present invention there is provided a welding apparatus comprising: i) Means for feeding an elongate metal item having a pair of edges requiring to be welded, into a welding assembly; ii) Pressure means within said welding assembly which cause said edges to achieve a required position relative one with the other; iii) Welding means activatable when said edges are presented thereto; iv) Temperature compensating means provided for a side of said item opposite the said edges to reduce bending of the item upon cooling after welding; and v) A feed-out means for receiving and transporting said item from said welding means after welding. 247 According to a still further aspect of the present invention there is provided a method and apparatus for welding substantially as herein described with reference to the accompanying drawings.

Further aspects of this invention which should be considered in all its novel aspects will become apparent from the following description given by way of example of possible embodiments thereof and in which reference is made to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1: Shows diagrammatically a side perspective view of a welding apparatus according to one possible embodiment of the invention; Figure 2; Shows an end view of an in-feed/out-feed part of the assembly of figure 1; Figure 3; Shows diagrammatically part of the former assembly of the welding assembly of figure 1? Figure 4; Shows diagrammatically an end elevation of the transporting frame assembly of figure 1; Figure 51 Shows diagrammatically a bottom ram holding portion of figure 1; Figure 6: Shows diagrammatically an end elevation view of part of the roller assembly of figure 1; 2 Figure 7: Shows diagrammatically a further portion of the roller assembly just prior to the welding head; Figure 8: Shows diagrammatically a further portion of the roller assembly at the welding head; Figure 9: Shows diagrammatically a lower portion of the assembly including a travelling earth; Figures 10 & 11: Shows a tracking assembly in an alternative embodiment of the invention to control the pole movement; Figures 12 & 13: Shows front and rear views of the tracking assembly of figures 10 and 11 in operation; and Figure 14: Shows a side view of the tracking assembly transporter for Figures 10 to 13.

BRIEF DESCRIPTION OF PREFERRED EMBODIMENTS Referring firstly to figure 1, a welding apparatus for elongate metal poles or the like is referenced generally by arrow 1.

As shown, the apparatus 1 is inclined at an angle A° which typically can be of the order of 7°-25° but would usually be of the order of 10°. This upward inclination may be of advantage in the welding of the elongate metal poles as they are fed through the apparatus 1. However a level or downwardly inclined 47 529 apparatus is also envisaged, the latter having the benefit of a gravity assisted feed-in of the poles.

The apparatus 1 is seen to comprise a feed-in portion 2, a former assembly 3, a welding head assembly 4, a post-weld feed-out portion 5 and a feed-out assembly 6.

The portions 3, 4 and 5 are shown combined together so as to provide a former/welder assembly referenced generally by arrow 7.

The feed-in and feed-out portions 2 and 6 are both shown provided with respective air ram or other pneumatic or hydraulic arrangements 8 and 9 to enable the assemblies 2 and 6 to be moved relative to the central assembly 7. In this way, the in-feed assembly 2 can be initially pivoted as indicated by arrow C so as to be substantially horizontal and in a position tending towards that shown in outline in figure 1 so as to facilitate the feeding-in of the elongate metal poles or the like. Once a pole has been fed in then the feed-in assembly 2 can be pivoted back to the position shown in solid lines in figure 1 and so as to be aligned with the central assembly 7.

Similarly, in the solid line position shown in figure 1, the feed-out assembly 6, being aligned with 47 529 the central assembly 7, is positioned to receive a welded pole following which the feed-out assembly 6 can be pivoted towards the horizontal as indicated by arrow B so as to facilitate a welded pole being fed-out.

A chassis 10 provides a support for chassis assembly 11 so as to maintain the total assembly at the desired angle relative to the ground or to provide support in a horizontal mode.

The apparatus 1 is, in one particular use, used for the automatic welding of a hollow tapered metal pole of octagonal cross-section. One such pole would be manually or automatically placed within the in-feed assembly 2 and the top and bottom rollers 12, 13 (see figure 2) brought together to engage the pole 14. In figure 2, the upper set of rollers 12 are shown driven by a motor 15 or the like. The rollers 12 and 13 are each shown provided with an inward taper 16 adapted to accommodate one of the corners of the octagonal section and to assist in holding and guiding the pole 14. The pole 14 will have its edges forming a gap 17, across which the weld is required, positioned so as to be accommodated within the inward taper 16 of the top roller 12. A further roller 40 is shown, suitably positioned between a pair of drive rollers 12, with its flange 41 extending down into the gap 17 so as to 247 5 prevent large poles overlapping their edges at the in-feed.

The roller 12 is shown with opposed raised edges 12a suitably serrated or roughened which will engage with and drive the pole 14 at the required speed. These edges 12a enable a more accurate drive speed to be achieved as they are defining a specific drive area rather than the larger area of the entire roller surfaces.

The bottom set of rollers 13 may, as shown, be idler rollers maintaining bottom pressure on the pole as it is fed through into the former/welding assembly 7. The bottom rollers 13 may be raised or lowered as indicated by arrows D.

The former assembly 3, see figures 3 and 6 for example, may be provided with an upper roller drive assembly 18 driven through motors 19 mounted on a top rail 20 which will work in conjunction with a bottom set of idler pressure rollers and driven side rollers 22 in providing radial pressure about the pole 14 so that it maintains its required shape as it approaches the welding apparatus 4 as well as the drive rollers providing the force moving the pole 14. The upper rollers 18, see figure 6 for example, are shown so disposed as to have their respective axes substantially 247 529 parallel to a respective face of the octagonal pole 14. This ensures that as the rollers 18 apply pressure to the faces of the pole 14, this pressure does not tend to distort the pole shape but instead ensures that the pole 14 is formed into the required shape. The side rollers 22 are shown engaging the pole edges between the faces. Rams or the like 23 are shown provided for each of the side rollers 22 so that the positioning of the rollers 22 relative to the pole 14 can be adjusted so as to be commensurate with the size of the pole 14, and particularly in the case of a tapered pole 14, its particular size at a particular point along its length. A bottom support ram 24 for the bottom set of rollers 21 also enables the bottom rollers 21 to be at a position commensurate with the required pressure to be applied on the pole 14.

In figures 4 and 5, further details of the former assembly 3 are shown with some components being omitted for clarity.

A ram 24 is shown provided on a bottom framework 25 in turn connected with a chain assembly 26. The chain assembly 26 is shown connected through an adjustable chain connector block 28 with a further chain assembly 27. The chain assembly 26 is also shown in figure 4 connected with one of the side arm mounts 29 and a similar connection being made with the other side 247529 arm mount (not shown). It is seen therefore that by means of the chain assemblies 26, 27, the positioning of the bottom rollers 21 and side rollers 22 can thereby be interlinked thus accommodating the shape of the pole 14.

Referring particularly to figure 7 the upper set of rollers 18 is shown to include one or more inner rollers 18A which suitably are provided with a substantially central disc or flange or the like 30. It has been found that particularly with the larger size poles, they tend to be flimsy with their edges tending to want to overlap. The flange or disc 30 on the inner roller 18A can therefore ensure that such overlapping does not take place and so that the adjacent edges of the pole 14 are kept apart a required distance.

In figure 8, looking back into the apparatus, the pole 14 is shown as having reached the welding head 4 and with the weld being made along the adjacent edges of the pole 14. Although not readily apparent from figures 1 and 8, the welding head 4 may be angled slightly towards the direction of the travel of the pole 14 as it has been found this may improve the quality of the weld thereby achieved. The gas formulation for the welding head 4 may require a carefully selected amount of oxygen, the oxygen content making the steel more fluid and lowering the surface tension. The welding wire 2475 should preferably have a substantial amount of deoxidizers such as manganese or silicon.

It is envisaged that specialised welding techniques may be utilised where suitable, such as the MAG process known as the Transferred Ionised Molten Energy (TIME) process.

One or more earthing rollers such as 21A will be provided so as to provide the necessary earthing connection for the pole 14. A further description of the earthing arrangement (not shown fully in Figure 8) follows below in respect of Figure 9.

In figure 8, the pre-weld drive rollers 43 are shown in outline behind the welding head 4. These rollers 43 may suitably be four in number being hardened flat faced rollers. They are suitably each adjustable in height in order to alter the gap between the pole edges at the weld point which in turn determines the penetration of the weld. In a four roller assembly, the middle two rollers would be set to be lower than the first and last rollers to facilitate achieving the desired effect. The motor 42 may be pivoted so that the rollers 43 allow the pole edges to move from side to side. The drive rollers 43 can then follow the edges without bursting the still hot and soft weld. 24752 9 Following the welding operation the welded pole 14 will be received by the feed-out assembly 6 which suitably will have the driven and idler rollers such as shown in figure 2. Once the pole 14 has left the former/welding assembly 7, the feed-out assembly 6 can be pivoted as indicated by arrow B in figure 1 so that the welded pole can then be fed out substantially horizontally. The welding operation can of course be made continuous so that poles are continuing to be fed through. In order that the positioning of the rollers, the commencement and termination of the welding operation, and the pivoting of the in-feed and out-feed assemblies etc. are all synchronised, in one embodiment of the invention a counter arrangement suitably using electronic pulses, may provide for the commencement of a pulse sequence when the entry of a pole is detected so that the various operations consequential on the entry of the pole can then be triggered when the pulse count reaches a prescribed number and in this way a very accurate sequencing of operations can be achieved.

By initiating a precision counter by the leading and trailing edge of the pole, the weld start and stop signals can be registered outside the welding area, thus enabling the sensors to be kept away from the damaging effects of the arc and the heat and smoke. The counter can suitably by driven by an encoder which can have a sensitivity enabling the reading of 0.4 nun of pole 247 5 movement. Where the poles are provided with cut-outs, these also need to sensed. Suitably the cut-outs in the bottom faces of the poles may be read at the in-feed by a proximity sensor on top of the pole and a proximity sensor on the bottom of the pole. If the bottom sensor is uncovered while the top one is still covered, then the machine knows that it has seen a cut-out and so a counter may be initiated that will remove and replace the appropriate rollers/rams at the correct time.

Alternative arrangements utilising time controls and/or photoelectric or mechanical switches for example will be readily apparent to those skilled in the engineering arts.

In Figure 8, a flame 45 is shown being applied to the under surface of the metal pole 14 through a heating tip 44. This provides a temperature compensation for the pole 14 to compensate for the heat generated on the opposite side of the pole 14 due to the welding operation. The flame 45 will act to balance the weld shrinkage and to act so as to maintain the pole 14 straight. Failure to provide this temperature compensation can result in the pole 14 being bent by the welding operation.

Referring now to Figure 9, a travelling earth arrangement is referenced generally by arrow 46 which is 2475 shown associated with the heating tip 44 so as to be movable along the under surface of the pole 14. The travelling earth arrangement 46 is shown both in full and in outline to illustrate its capability of movement commensurate with the movement of the pole. The travelling earth 46 comprises an earth tab 47, movable at the end of a ram 48 so that in its raised position, it can be engaged by the leading edge of the pole to be carried with it providing the earthing of the pole until at the appropriate point, the tab 47 will be pulled away by the ram 48 and the earthing being then switched, such as by a solenoid, to the earth roller 21a.

It has been found that by providing such a travelling earth, arc blow can be overcome or at least substantially reduced, this being the undesirable displacement of the arc plasma caused by the magnetic fields set up about the weld. A bottom ram 49 is suitably activated so as to return the travelling earth 46 to its position of rest waiting for the next pole.

The heating tip 44 is again shown in Figure 9 of a type to provide a broad gas flame. It is mentioned however that this temperature compensation function could possibly be done in alternative fashion such as by using a TIG arc or the like. 47 In the above embodiment the rollers 21, 22 etc. of the former and welding areas 3, 5 have not in all instances been able to prevent the edges 17 of the pole 14 from wandering as it was welded. This has necessitated an operator to follow the seam with the weld head. The pole rotation is typically caused by small differences in pressure between the rams on each side of the apparatus and the internal friction as the pole is transported. To overcome or at least reduce this problem a pole tracking assembly is shown in figures 10 to 14 which is able to provide a vertical and lateral datum for the pole edges. The tracking assembly is referenced generally by arrow 50 in figures 10 and 11 and is shown having a roller or disc 51, provided on a shaft 52, which can engage between the edges 17 of the pole 14 (see figure 12). The roller shaft assembly 51, 52 is associated on either side with a wheel or roller 53 provided with a rib or profile 54 which can engage in a "V" trough or recess 55 in a guide member 56 to therefore set the horizontal or lateral datum line for the pole edges 17. A further roller 57 may then be provided so as to engage with the pole 14 behind the roller 51 so as to maintain a vertical datum height for the pole 14.

A large number of the roller pairs 53, 57 can suitably be provided, as illustrated in figure 14 for example. Here a pair of chains 58 (only one on one side 247 5 being shown) can have the roller pairs 54, 57 mounted between them with the ribs or profiles 54 being able to be moved along with the pole 14, rather than having to rotate and be more prone to wear, and in maintaining the lateral positioning of the pole edges 17.

The height of the rollers 51 relative to the rollers 57 can be adjustable and this may be able to provide some influence on the setting of the weld gap. A front roller indicated at 60 in outline in figure 14 may suitably be provided so as to prevent the "V" rollers 53 from pulling the pole edges 17 upwards as the rollers 53 are withdrawn. The roller 60 may also assist in setting the final weld gap by pushing the welding edges towards the vertical datum line and tending to close the edges 17 up.

It is seen therefore that the present apparatus and method enables a continuous weld to be achieved along the elongate metal item such as the pole 14 thus avoiding the disadvantages inherent if tack welding were used.

Where in the foregoing description reference has been made to specific components or integers of the invention having known equivalents then such equivalents are herein incorporated as if individually set forth. 247 5 Although this invention has been described by way of example and with reference to possible embodiments thereof it is to be understood that modifications or improvements may be made thereto without departing from the scope appended claims of the invention as defined in the appended claims. 2 4 7529

Claims (18)

WHAT WE CLAIM IS:

1. A method of welding an elongate metal item along a pair of adjacent edges, said method comprising: (i) Providing a controlled feed of said item into a welding assembly; (ii) Applying pressure about said metal item as it travels through said welding assembly so as to obtain a required positioning of said edges relative one with the other; (iii) Providing a welding means activated when said edges are presented thereto; (iv) Providing a temperature compensation for a side of said item opposite the said edges to reduce bending of the item upon cooling after welding; and (v) Providing feed means to receive and transport said item after welding, out of said welding assembly.

2. A method as claimed in Claim 1 wherein said item comprises a tapered metal pole and wherein the steps of providing a controlled feed of said item ■ and applying pressure about said item include the provision of roller assemblies adapted to engage with said pole as it travels to and through said welding assembly.

A method as claimed in Claim 2 wherein said roller assemblies include roller means which can engage with said edges to control their positioning.

A method as claimed in Claim 3 wherein said roller means includes a flange which can extend between said edges.

A method as claimed in Claim 3 or Claim 4 wherein said roller means includes a guide means to control the lateral position of said roller means relative to said edges and thereby the lateral positioning of said edges.

A method as claimed in any one of Claims 3 to 5 and wherein a vertical adjustment is provided for a further roller means engagable with said item so as to control the height of said edges.

A method substantially as herein described with reference to figures 1 to 9 or figures 1 to 14 of the accompanying drawings.

A welding apparatus comprising: (i) Means for feeding an elongate metal item having a pair of edges requiring to be welded into a welding assembly; - 21 - 247 529 (ii) Pressure means within said welding assembly which cause said edges to achieve a required position relative one with the other; (iii) Welding means activatable when said edges are presented thereto; (iv) Temperature compensating means provided for a side of said item opposite the said edges to reduce bending of the item upon cooling after welding; and (v) Peed-out means for receiving and transporting said item from said welding means after welding.

A welding apparatus as claimed in Claim 8 wherein said pressure means comprises a plurality of roller assemblies adapted to engage with said metal item and including engagement means to engage with said edges.

A welding apparatus as claimed in Claim 9 wherein said engagement means includes a flange adapted to engage between said edges.

A welding apparatus as claimed in Claim 9 or Claim 10 wherein said engagement means includes a roller adapted to engage between said edges adjacent said welding means and wherein said roller includes lateral positioning means to control the lateral positioning of said edges. - 22 - 247529

12. A welding apparatus as claimed in Claim 11 wherein said lateral positioning means comprises at least one profiled member adapted to engage within a corresponding profile provided in a guide member.

13. A welding apparatus as claimed in any one of Claims 8 to 12 and including at least one further roller means vertically adjustable relative to said edges and adapted to engage with said item so as control the vertical positioning of said edges.

14. A welding apparatus as claimed in any one of Claims 8 to 13 wherein said feeding means includes at least one roller member having an inward taper adapted to accommodate and guide a portion of said metal item and wherein said roller member further includes at least one raised edge which projects above said inward taper so as to contact with and drive said metal item.

15. A welding apparatus as claimed in any one of Claims 8 to 14 wherein a plurality of roller assemblies having lateral alignment control and vertical control means are provided on a transporting means adapted to move with said item as it travels towards said welding means. 23

16. A welding apparatus as claimed in any one of Claims 8 to 15 wherein the travel of said item is detected by a counter arrangement which triggers a sequencing of the welding operations.

17. A welding apparatus as claimed in any one of Claims 8 to 16 wherein an earthing arrangement can be engaged by a leading edge of said item to travel with it towards said welding means before being released.

18. A welding apparatus substantially as herein described with reference to figures 1 to 9 or figures 1 to 14 of the accompanying drawings.