IES61126B2 - A welding jig - Google Patents

Description

The present invention relates to a welding jig for supporting and locating a plurality of components of a work piece to be welded. The invention also relates to a method for welding the components of the work piece using the welding jig.

Welding jigs for locating and supporting components of a work piece 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 work piece comprises a number of components, and some of the joints to be welded are difficult to access. In many cases, after welding some of the joints and tacking others of the joints together, it is necessary to Ο < Η Π Τ' > · I <_ Ο 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 work piece .

There is therefore a need for a welding jig for supporting, and locating components of a work piece to be welded which overcomes these problems, there is also a need for a method for using the welding jig for welding the components of a work piece together.

The present invention is directed towards providing such a welding jig and a method.

According to the invention there is provided a welding jig for supporting and locating components of a work piece to be welded, the welding jig comprising a main chassis, a jig means for supporting and locating the components of the work piece, a mounting means for rotatably mounting the jig means in the main chassis about a rotational axis, a securing means for selectively securing the jig means in a plurality of orientations relative to the main chassis for presenting the work piece to an operator at different orientations .

In one embodiment of the invention the mounting means comprises an elongated shaft extending outwardly from respective opposite ends of the jig means, and defining the rotational axis, and bearing means on the main chassis for rotatably carrying the shaft.

In another embodiment of the invention the securing means comprises a first engagement means mounted on one of the jig means and the main chassis, and a plurality of complimentary second engagement means engagable with the first engagement means, the second engagement means being mounted on the other of the jig means and the main chassis. Preferably, the first engagement means is mounted on the jig means, and the second engagement means is mounted on the main chassis. Advantageously, the second engagement means are circumferentially spaced apart from each other around the rotational axis. Preferably, the second engagement means are equi-spaced around the rotational axis.

In one embodiment of the invention at least four second engagement means are provided. Advantageously, at least eight second engagement means are provided.

In one embodiment of the invention the first engagement means comprises an engagement pin movable Λ between an engaged position engaging any one of the second engagement means, and a disengaged position disengaged from the second engagement means to permit rotation of the jig means. Advantageously, each second engagement means is formed by an engagement opening for releasably receiving the engagement pin. Preferably, the engagement pin extends parallel to the rotational axis of the jig means, and is axially slidable between the engaged and the disengaged positions. Advantageously, the engagement openings are formed in a fixed annular disc extending around the shaft, and rigidly mounted to the main chassis.

In one embodiment of the invention the first engagement means is urged into engagement with the second engagement means. Preferably, the first engagement means is spring urged into engagement with the second engagement means.

In another embodiment of the invention a brake means is provided for controlling the rotational speed of the jig means relative to the main chassis. Preferably, the brake means is adjustable for permitting adjustment of the rotational speed of the jig means relative to the main chassis.

Advantageously, the brake means comprises a braking disc rigidly mounted on the jig means co-axial with the rotational axis and rotatable therewith, the braking disc being located adjacent the fixed disc and co-axially aligned therewith, and having a first radial surface which faces a second radial surface of the fixed disc, friction means being provided between the first and second surfaces for co-operating with the first and second surfaces for controlling the speed of the jig means.

In one embodiment of the invention the friction means comprises a disc of friction material, the friction disc being co-axial with the rotational axis of the jig means and rotatable relative to the fixed and braking discs. Advantageously, the braking disc, the fixed disc and the friction disc are circular.

Preferably, the first engagement means is mounted on the braking disc.

In one embodiment of the invention the braking disc and fixed disc are movable axially relative to each other, and fixing means for fixing the relative axial positions of the respective discs is provided.

In another embodiment of the invention the jig means is provided with a receiving surface for receiving the components of the work piece, the receiving surface extending between a pair of spaced apart opposite side edges extending longitudinally parallel to the rotational axis of the jig means. Preferably, the rotational axis is located intermediate the side edges of the receiving surface. Advantageously, the rotational axis is located substantially half way between the side edges of the receiving surface.

In another embodiment of the invention the receiving surface extends between a pair of spaced apart opposite end edges extending between the side edges.

Preferably the jig means is provided with a pair of opposite receiving surfaces. Advantageously, the rotational axis is located intermediate the respective receiving surfaces. Preferably, each receiving surface is formed by a platform.

In one embodiment of the invention the jig means comprises a sub-frame and each platform is mounted to the sub-frame. Preferably, the shaft extend from opposite ends of the sub-frame.

In another embodiment of the invention locating means and clamp means are provided on each receiving surface for locating and clamping the components of the work piece thereto.

Preferably, the rotational axis of the jig means extends substantially horizontally.

Additionally, the invention provides a method for welding components of a work piece using the welding jig according to the invention, the method comprising the steps of securing the jig means relative to the main chassis in one of the plurality of orientations, placing and locating the components on the jig means, clamping the located components to the jig means, welding at least some of the components together, rotating the jig means relative to the main chassis to another of the plurality of orientations and securing the jig means relative to the main chassis in the selected orientation, further welding the components of the work piece.

In one embodiment of the invention the method comprises the further step of further rotating the jig means relative to the main chassis into another of the plurality of orientations for carrying out further welding of the components, and securing the jig means in the selected location.

In another embodiment of the invention the jig means is rotated into another of the plurality of orientations and secured therein prior to welding the components after the components have been located and clamped on the jig means.

In a further embodiment of the invention the work piece is cleaned prior to removal from the jig means.

In a still further embodiment of the invention the jig means is rotated into another of the plurality of orientations and secured therein prior to cleaning of the work piece.

In another embodiment of the invention the work piece is removed from the jig means after cleaning.

Additionally, the invention provides a work piece comprising a plurality of components welded together on the welding jig according to the invention.

Further the invention provides a work piece comprising a plurality of components welded together using the method according to the invention.

In one embodiment of the invention the work piece is a framework.

The invention will be more clearly understood from the following description of a preferred embodiment ft thereof given by way of example only, with reference to the accompany drawings, in which: Fig. is a perspective view ox a welding jig according to the invention, Fig. is an end elevational view of the welding jig in one orientation.

Fig is a view similar to Fig. 2 illustrating 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 cross-sectional view of a detail of the welding jig of Fig. 1 on the line V-V of Fig. 2, Fig. 6 is a view similar to Fig. 5 of the detail of Fig. 5 illustrating portion of the detail of Fig. 5 in a different position, Fig. 7 is a cut-away perspective view of portion of the welding jig of Fig. 1, Fig. 8 is a cross-sectional end elevational view of portion of the detail of Fig. 5 on the line VIII-VIII of Fig. 5, and Fig. 9 is a perspective view of a work piece 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 work piece 3. Briefly, the work piece 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 δ which extend continuously around each joint 7, see Fig. 9. The work piece 3 is a particularly high procession 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 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 box-section 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 ox 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 work piece 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 work pieces, 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. 9.

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 rotatably mounted in a housing 42 of each bearing 35 engages and locates the shaft 34 relative to the main chassis 10. Grub screws 43 in the sleeves 41 locate and secure the shaft 34 in the sleeves 41 for locating the jig member 20 relative to the main chassis 10.

Brake means for controlling the rotational speed of the jig member 20 relative to the main chassis 10 comprises a fixed annular disc 45 of steel which is welded to one of the support plates 40, and a braking disc 46 also of steel which is welded to the shaft 34 and is co-operable with the fixed disc 45. The fixed disc 45 and braking disc 46 are co-axial with the shaft 34. The braking disc 46 and the fixed disc 45 are provided with respective first and second radial faces 48 and 49 which face each other. A friction means comprising a friction disc 50 is located between the fixed disc 45 and the braking disc 46 and is rotatable on the shaft 34 and is co-operable with the first and second faces 48 and 49, respectively, for controlling the rotational speed of the jig member 20 relative to the main chassis 10. Adjusting means for adjusting the braking force between the discs 45 and 46 and the friction disc 50 for varying the rotational speed of the jig member 20 in the main chassis 10 is provided by axially sliding the shaft 34 in the respective sleeves 41 of the bearings 35 for varying the pressure between the first and second faces 48 and 49, respectively and the friction disc 50. Thus, the grub screws 43 effectively act as adjusting means for adjusting the braking force. By loosening the grub screws 43 the shaft 34 may be axially slid in the sleeves 41 until the desired braking pressure between the discs 45, 46 and 50 is achieved, at which stage the grub screws 43 are secured to hold the shaft 34 captive in the sleeves 41.

Securing means comprising complimentary inter15 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 work piece 3. The first engagement means comprises an engagement pin 55 of circular cross-section slidably carried in a cylindrical housing 56 of steel welded to the braking disc 46. A plurality of second engagement means formed by eight engagement openings 58 which are provided at circumferentially equi-spaced intervals around the fixed disc 45 for releasably receiving the engagement pin 55. The engagement pin 55 is of steel of circular cross-section and is slidable in a bore 60 extending through the cylindrical housing 56 parallel to the rotational axis 21 of the jig member 20. The engagement pin 55 is slidable from an engaged position illustrated in Fig. 5 engaging one of the engagement openings 58 for securing the jig member 20 in one of the orientations relative to the main chassis 10 to a disengaged position illustrated, in Fig. 6 disengaged from the engagement openings 58 to permit rotation of the jig member 20 relative to the main chassis 10. A compression spring 62 located in the bore 60 in the cylindrical housing 56 acts between a shoulder 63 in the bore 60 and a flange 64 on the engagement pin 55 for spring urging the engagement pin 55 into the engaged position. An opening 65 which is axially aligned with the bore 60 in the braking disc 46 accommodates the engagement pin 55 into the engagement openings 58 = The engagement openings 58 are of circular cross-section and of diameter substantially similar to the diameter of the engagement pin 55 to facilitate sliding engagement between the engagement pin 55 and the respective engagement openings 58, and also to facilitate securing the jig member 20 to the main chassis 10 relatively securely without angular play between the jig member 20 and the main chassis 10 when secured by the engagement pin 55= A knob 67 is provided on the engagement pin 55 to facilitate sliding the engagement pin between the engaged and disengaged positions. The outer diameter of the friction disc 50 is such as to provide clearance for the engagement pin 55.

In use, the receiving surface 25 of the appropriate platform 24 corresponding to the work piece 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 work piece 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 work piece 3 thereon is in a desired orientation so that other parts of the joints 7 become more easily assessable. 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 assessable. 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 work piece 3 secured on the receiving surface 25 have been welded» The clamps 32 are then released and the work piece 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 work piece 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. The components 2 are located and clamped on the receiving surface 25. Welding of the components 2 of the work piece 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 work piece 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 the seam 5 between joints 7 of the work piece 3 can be seam welded prior to the work piece 3 being removed from the jig member 20. This thus, provides a considerably more dimensionally accurate work piece.

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 work piece 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 work pieces.

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 is provided, any other suitable brake means may be used.

Claims (5)

1. A welding jig for supporting and locating components of a work piece to be welded, the welding jig comprising a main chassis, a jig means for supporting and locating the components of the work piece, a mounting means for rotatably mounting the jig means in the main chassis about a rotational axis, a securing means for selectively securing the jig means in a plurality of orientations relative to the main chassis for presenting the work piece to an operator at different orientations.

2. A welding jig as claimed in Claim 1 in which the mounting means comprises an elongated shaft extending outwardly from respective opposite ends of the jig means, and defining the rotational axis, and bearing means on the main chassis for rotatably carrying the shaft.

3. A welding jig as claimed in Claim 1 or 2 in which the securing means comprises a first engagement means mounted on one of the jig means and the main chassis, and a plurality of complimentary second engagement means engagable with the first engagement means, the second engagement means being mounted on the other of the jig means and the main chassis.

4. A method for welding components of a work piece using the welding jig of any preceding claim, the method comprising the steps of securing the jig means relative to the main chassis in one of the plurality 5. Of orientations, placing and locating the components on the jig means, clamping the located components to the jig means, welding at least some of the components together, rotating the jig means relative to the main chassis to another of the plurality of orientations 6. 10 and securing the jig means relative to the main chassis in the selected orientation, further welding the components of the work piece.

5. A work piece comprising a plurality of components welded together on the welding jig of any of Claims 1 15 to 34.