IES70919B2

IES70919B2 - A welding jig

Info

Publication number: IES70919B2
Authority: IE
Inventors: Joseph Augustine Higgins
Original assignee: Joseph Augustine Higgins
Priority date: 1993-11-01
Filing date: 1993-11-01
Publication date: 1997-01-15
Also published as: IES70921B2; IE71656B1; IE930832A1; IES70920B2; GB2283447A; GB9400588D0

Abstract

A welding jig (1) comprises a main chassis (10) on which jig member (20) for locating and clamping components (2) to be welded is rotatably mounted for movement into a plurality of different orientations to facilitate accessing joints (7) to be welded. A spring loaded engagement pin (55) slidable in a housing (56) is mounted on a braking disc (46) fast on one of the shaft (34) is selectively engagable with eight engagement openings (58) in a fixed disc (45) mounted on the main chassis (10) for selectively securing the jig member (20) in eight respective desired orientations. A brake is provided to control rotation and the workpiece may be cleaned while still mounted on the jig.

Description

The present invention relates to a welding jig for supporting and locating a plurality of components of a workpiece to be welded.

Welding jigs for locating and supporting components of a workpiece during welding are known. In general, such jigs comprise a platform or framework on which locating means for locating the components relative to each other are provided, and clamping means, in general, are also provided for clamping the components in position when located. Depending on the size of such jigs, they may be placed on a work bench, or on the floor. However, where jigs are relatively large, in general, they must be left in the one orientation, either placed on the ground or placed on the work bench. Thus, all welds which are required to weld the components together must be carried out with the jig in this orientation. In many cases, this presents major problems, particularly, where the workpiece comprises a number of components, and some of the joints to be welded are difficult to access. In such cases, after welding some of the joints and tacking others of the joints together, it is necessary to remove the components from the jig for welding of the remainder of the joints which are difficult to access from the jig. This, it will be appreciated has many disadvantages, in that it is inefficient, and can seriously affect the dimensional accuracy of the fully welded workpiece.

There is therefore a need for a welding jig for supporting and locating components of a workpiece to be welded which overcomes these problems. ι»ι 19 - 2 The present invention is directed towards providing such a welding jig* statements of Invention According to the invention there is provided a welding jig for supporting and locating components of a workpiece to be welded, the welding jig comprising a main chassis, a jig means for supporting and locating the components of the workpiece, a mounting means formed from an elongated shaft extending outwardly from respective opposite ends of the jig means, and defining a rotational axis, and bearing means on the main chassis for rotatably carrying the shaft, a securing means for selectively securing the jig means in a plurality of orientations relative to the main chassis for presenting the workpiece to an operator at different orientations, and in which the jig means is provided with two receiving surfaces for receiving the components of the workpiece, the receiving surfaces extending between a pair of spaced apart opposite side edges extending longitudinally parallel to the rotational axis of the jig means and substantially half way between the side edges of the receiving surface.

By providing a work surface that is effectively two-sided, there is a considerable increase in efficiency and throughput and in particular it makes it much easier for the welder to carry out work, particularly in that generally speaking, two workpieces would be loaded onto the one welding jig, further balancing the jig and making it much easier to operate and use.

Further, the invention provides a welding jig in which each receiving surface extends between a pair of spaced apart opposite end edges extending between the side edges and is formed by a platform mounted on a sub-frame which in turn comprises the jig means.

Having a sub-frame makes it particularly effective and efficient in use in that a sturdy frame is provided which allows for precision welding and it is important to appreciate that the principal function of the welding jig according to the present invention is to provide for accurate, quick and reproducible welding on a regular basis of frames and the like workpieces.

Preferably, locating means and clamp means are provided on each receiving surface for locating and clamping the components of the workpiece thereto. The advantage of this is that it is possible to provide a platform which can be replaceable and which can have accurate location means on it to ensure that precision welding is achieved every time and that the product produced has the desired final- finish.

Further the invention provides a workpiece comprising a pluality of components welded together on the welding jig according to the invention.

Detailed Description of the Invention The invention will be more clearly understood from the following description of a preferred embodiment thereof given by way of example only, with reference to the accompanying drawings in which:Fig. 1 is a perspective view of a welding jig according to the invention; Fig. 2 is an end elevational view of the welding jig in one orientation; Fig. 3 is a view similar to Fig. 2 illustrated the welding jig in another orientation; Fig. 4 is a view similar to Fig. 2 illustrating the welding jig in a further different orientation; Fig. 5 is a cut-away perspective view of portion of the welding jig of Fig. 1; Fig. 6 is a typical cross-sectional end elevational view of portion of the detail of Fig. 1 to illustrate a disc forming part of the invention; and Fig. 7 is a perspective view of a workpiece also according to the invention which was welded together on the welding jig of Fig. 1.

Referring to the drawings there is illustrated a welding jig according to the invention indicated generally by the reference numeral 1 for locating and supporting a plurality of components 2 which are to be welded together to form a workpiece 3. Briefly, the workpiece 3 is a framework comprising a plurality of the components 2 which are struts 5 of box-section material which are all seam welded together by seam welds 6 which extend continuously around each joint 7, see Fig. 7. The workpiece 3 is a particularly high precision framework, and accordingly, it is essential that when the component struts 2 are welded together that the framework is dimensionally accurate.

The welding jig 1 comprises a main chassis 10 which comprises a ground engaging base frame 11, and a pair of uprights 12 extending upwardly from opposite ends of the base frame 11. The base frame 11 comprises a pair of spaced apart longitudinally extending side members 15 of - 5 channel section steel joined by end members 16, also of channel section steel. The uprights are of box steel and extend upwardly from the end members 16 and are located and strengthened by pairs of inclined struts 17 of boxsection steel extending from the end members 16. The base frame 11, uprights 12 and struts 17 are welded together.

A jig means for locating and supporting the components 2 during welding comprises a double sided jig member 20 which is rotatably mounted about a horizontal rotational axis 21 through a plurality of orientations relative to the main chassis 10, as will be described below. The jig member 20 comprises a sub-frame 23 which supports a pair of platforms 24a and 24b of steel plate material on opposite sides thereof which respectively define opposite receiving surfaces 25a and 25b for receiving the components 2 to be welded. The sub-frame 23 comprises a pair of longitudinally extending side members 26 joined by end members 27 all of channel section steel welded together. The platforms 24 are of steel plate material secured to the sub-frame 23 by screws (not shown).

A plurality of locating means, namely, locating members 30 of steel are secured to the receiving surfaces 25 of the respective platforms 24 for locating the components 2 in position on the receiving surfaces 25. A plurality of clamping means comprising a plurality of clamps 32 are mounted on the receiving surfaces 25 of the respective platforms 24 and cooperate with the locating members 30 and the receiving surfaces 25 for clamping the components 2 of the workpiece 3 in their correct location for welding. Since the provision of such locating members and clamps on a receiving surface 25 of a jig will be well known to those skilled in the art, it is not intended to describe the locating members 30 and clamps 32 further, nor is it intended to describe the platforms 24 and their respective receiving surfaces 25 in any further detail, indeed, only some of the locating members 30 and the clamps 32 are illustrated. In practice more will be required.

In this embodiment of the invention the locating members 30 and clamps 32 are arranged on the receiving surfaces 25 of the platforms 24 to accommodate components of two different types of workpieces, namely, two different frameworks, however, the frameworks are both for use in the same end product. Only one of the frameworks is illustrated in Fig. 7.

Mounting means comprising an elongated shaft 34 of steel extends through the sub-frame 23 and outwardly from the jig member 20 at opposite ends thereof and is rotatably carried on the main chassis 10 by a pair of bearings 35 mounted on the uprights 12 of the main chassis 10 for rotatably mounting the jig member 20 about the rotational axis 21. The shaft 34 extends through mounting plates 37 of steel which are secured by welding to the end members 27 of the sub-frame 23, and the shaft 34 defines the rotational axis 21 of the jig member 20. Side edges 38 of the platforms 24 extend parallel to the rotational axis 21, and the rotational axis 21 lies halfway between the side edges 38, and halfway between the platforms 24. The bearings 35 are plummer block bearings which are secured by screws (not shown) to horizontal support plates 40 of steel supported on and welded to the tops of the uprights 12. A sleeve 41 (see the right hand side of Fig. 1) rotatably mounted in a housing of each bearing 35 engages and locates the shaft 34 relative to the main chassis 10 being secured to the shaft 34 by grub screws 43 (not shown).

Brake means for controlling the rotational speed of the jig member 20 relative to the main chassis 10 is provided and is not described in any more detail as it does not form part of this invention, except to state that it comprises a disc 46 welded to the shaft 34 which cooperates with a fixed disc 45.

Securing means comprising complementary inter-engagable first and second engagement means are provided for selectively securing the jig member 20 in each of the plurality of orientations, which in this case, are eight orientations so that the receiving surfaces 25a and 25b of the platforms 24a and 24b may be presented in any of the various orientations relative to the main chassis 10 to an operator to facilitate welding of the components 2 of the workpiece 3. The first engagement means comprises an engagement pin 55 of circular cross-section slidably carried in a cylindrical housing of steel welded to the braking disc 46. A plurality of second engagement means formed by eight engagement openings 58 are provided at circumferentially equi-spaced intervals around the fixed disc 45 for releasably receiving the engagement pin 55. These are illustrated in Fig. 6. This indexing arrangement requires no further description as it does not form part of the invention.

In use, the receiving surface 25 of the appropriate platform 24 corresponding to the workpiece 3 which is to be welded is selected. With the engagement pin 55 held in the disengaged position the jig member 20 is rotated relative to the main chassis 10 until the selected receiving surface 25 is in the horizontal position. The engagement pin 55 is moved into the engaged position engaging the appropriate engagement opening 58 for securing the jig member 20 in the horizontal orientation. The components 2 of the workpiece 3 are then placed on the receiving surface 25 and are located in their correct positions by the locating members 30. The clamps 32 are operated to clamp the located components relative to each other. While the receiving surface 25 of the jig member 20 is horizontal, the parts of the joints 7 between the components 2 which can readily easily be seam welded are seam welded. Once the part of all the joints 7 between the components have been partly seam welded, or at least tacked, the engagement pin 55 is moved into and held in the disengaged position, and the jig member 20 is rotated until the receiving surface 25 with the workpiece 3 thereon is in a desired orientation so that other parts of the joints 7 become more easily accessible. The engagement pin 55 is moved into the engaged position engaging the appropriate engagement opening 58 for securing the jig member 20 in the selected orientation. These parts of the joints 7 are then welded. The engagement pin 55 is again moved into the disengaged position and the jig member 20 is rotated into another orientation where further parts of the joints 7 between the components 2 become more easily accessible. The engagement pin 55 is moved into the engaged position engaging the appropriate engagement opening 58 for securing the jig member 20 in the selected orientation. These parts of the joints are then welded, and if necessary, the jig member 20 is again rotated into a further orientation, and so on, until all the parts of the joints 7 which can be accessed with the workpiece 3 secured on the receiving surface 25 have been welded. The clamps 32 are then released and the workpiece 3 is removed from the receiving surface 25. Any remaining parts of the joints 7 which have not already been seam welded are now seam welded.

When it is desired to weld components 2 of the other workpiece for which the locating members 30 and clamps 32 are arranged on the other receiving surface 25, with the engagement pin held in the disengaged position, the jig member 20 is rotated until the appropriate receiving surface 25 is horizontal. Thus, if originally the receiving surface 25a had been used, now the receiving surface 25b would be used. The components 2 are located and clamped on the receiving surface 25. Welding of the components 2 of the workpiece 3 is similar to that already described.

The advantages of the invention are many. The main advantage of the invention is that by virtue of the fact that the jig member 20 is rotatable and may be secured in a number, in this case, eight different orientations, parts of joints between the components 2 forming the workpiece 3, which would otherwise be inaccessible while the components are clamped on the receiving surface 25, and the receiving surface is horizontal or is provided in one fixed orientation, can readily easily be accessed by merely changing the orientation of the jig member 20. Thus, by using the welding jig 1 according to the invention considerably greater lengths of seam 6 between joints 7 of the workpiece 3 can be seam welded prior to the workpiece 3 being removed from the jig member 20. This thus, provides a considerably more dimensionally accurate workpiece.

While the welding jig has been described as comprising a main chassis of particular shape and construction, other suitable forms of main chassis may be provided. Needless to say, other suitable jig means may be provided. It will of course be appreciated that other suitable locating means and clamp means for locating and clamping the components of the workpiece to the jig means may be provided, and of course it will be readily apparent to those skilled in the art that the location and orientation of the locating members and clamps may be rearranged for receiving components of other workpieces.

While a particular construction of securing means has been provided, other suitable securing means may be provided, and while it is preferable, it is not essential to provide brake means. Where brake means are provided, any other suitable brake means may be used.

CL&IiiS

Claims

1. A welding jig for supporting and locating components of a workpiece to be welded, the welding jig comprising a main chassis, a jig means for supporting and locating the components of the workpiece, a mounting means formed from an elongated shaft extending outwardly from respective opposite ends of the jig means, and defining a rotational axis, and bearing means on the main chassis for rotatably carrying the shaft, a securing means for selectively securing the jig means in a plurality of orientations relative to the main chassis for presenting the workpiece to an operator at different orientations, and in which the jig means is provided with two receiving surfaces for receiving the components of the workpiece, the receiving surfaces extending between a pair of spaced apart opposite side edges extending longitudinally parallel to the rotational axis of the jig means and substantially half way between the side edges of the receiving surface.

2. A welding jig as claimed in Claim 1 in which each receiving surface extends between a pair of spaced apart opposite end edges extending between the side edges and is formed by a platform mounted on a subframe which in turn comprises the jig means.

3. A welding jig as claimed in any preceding claim in which locating means and clamp means are provided on each receiving surface for locating and clamping the components of the workpiece thereto.

4. A welding jig substantially as described herein with reference to and as illustrated in the accompanying drawings.

5. A workpiece comprising a plurality of components welded together on the welding jig of any preceding claim. CRUICKSHANK & CO., S708 IS 1/3 (FORMAL) <1 ♦ Fis 1 $70«10 (fobwl)2/3 θ m Ai cd f © l£ $70119