Description of Invention This invention relates to a method for maintaining a plurality of articles in spaced relationship with each other, and particularly, but not exclusively, to a method for maintaining articles in spaced relationship with each other when it is desired that the articles do not come into contact with each other, such as, for example, when the articles are being subjected to a treatment.

In the case of electro-coating articles, it is conventional for the articles concerned to be suspended from an array or row of hooks, with the hooks passing through apertures within the articles, such that the articles are relatively freely suspended below an overhead support bar, for subsequent immersion into a vessel such as an electro-coating tank. However, such an arrangement suffers from two major problems.

The first is that as the articles are relatively freely suspended from the hooks, they are liable to move relative to each other, both during the electro- coating process due to fluid agitation within the tank, and also during transportation between adjacent tanks used in the process.

The result is that the articles may come into contact with one another, such that the quality and extent of the coating applied to the articles is compromised. To overcome this problem, it has hitheao been necessary to space the articles from each other to such an extent where contact between them is not possible with the result that the number of articles which may be suspended from a given support bar is severely limited.

It is therefore an object of the present invention to provide an improved method for maintaining a plurality of articles in spaced relationship with each other, such as may be applicable to such a coating process.

A further problem which commonly arises during electro-coating processes is that the jigs which cany the articles, both before and after treatment, become immersed in the electro-coating fluid and are thus subject to electro-coating in the same way as are the articles carried by the jigs.

The result of this is that the surfaces of the jigs become electrically insulated by the coating (eg a paint film) which must be removed prior to re-use such that electrical contact may once again be made with the jig.

Conventionally, such removal has been performed by shot blasting the entire jig, or at least the electrical contact points, by burning off (smouldering) in a temperature controlled oven, by chemical paint stripping, or by use of an abrasive such as a file across the points of contact.

All of these solutions however are costly in terms of time and resources.

It is thus a fuuher object of the present invention to provide an improved apparatus or jig for use in such treatment processes.

According to a first aspect of the invention, there is provided a method for maintaining a plurality of articles in spaced relationship with each other, comprising inserting an elongate member having an uneven extemal surface into an aperture in each article, and supporting the elongate member.

Conveniently, the extemal surface of the elongate member comprises a series of raised formations and recesses such as crests and troughs, desirably provided by a screw threaded formation.

The method may further comprise moving the elongate member to a generally upright condition so that the articles engage the elongate member in such a manner that movement of the articles along the axis of the elongate member is impeded.

Preferably, the elongate member is inserted into the aperture in each article such that the centre of gravity of each article is spaced from the axis of the elongate member.

In this way, when the elongate member is moved to a generally upright condition, the articles pivot generally around the aperture through which the elongate member is passed, to a position at which they remain relatively securely engaged with the elongate member, such that movement of the articles along the axis of the elongate member is impeded. With the elongate member in a generally upright condition, the articles may engage the elongate member at two positions around the aperture, generally, on opposite sides of the aperture.

It will be appreciated that whilst a variety of different sized apertures and threaded elongate members may be used, the relationship between the diameter of aperture and diameter of elongate member will determine the angle at which the article will be"suspended"from the elongate member when the elongate member is in a generally upright condition.

Thus, if the diameter of the aperture is significantly greater than the diameter of the elongate member, the article concerned will attain a more vertical position when engaged with the elongate member than if the apertures of the article and diameter of the elongate member were more similar.

It is often desirable that the articles should be maintained in as close a relationship as possible, whilst still maintaining some clearance between adjacent articles such that the coating to be applied thereto may be applied to all (or substantially all) the exterior surface of the article. In view of this, it may be convenient for the difference between the articles'aperture diameter and the diameter of the elongate member to be no more than 20% and desirably, no more than 10%.

In an alternative the elongate member is suppoited substantially horizontally on support members.

Preferably each support member has an uneven extemal surface which comprises a series of raised formations and recesses, these are conveniently provided by a screw threaded formation.

Each support member may comprise a plurality of recesses for receipt of the elongate members.

Conveniently the plurality of recesses is provided by a plurality of adjacent formations upstanding from the support member. The formations upstanding from the support member are preferably substantially triangular, to provide substantially V-shaped recesses.

According to a second aspect of the invention there is provided an apparatus for maintaining a plurality of articles, each having an aperture therein, in spaced relationship to each other comprising a plurality of elongate members for insertion through the apertures in the articles and having uneven external surfaces, and support means adapted in use to support the elongate members.

The support means may comprise a plurality of apertures each of which is adapted for receipt of an end of an elongate member such that each elongate member is supporte in a substantially vertical orientation.

The support means may conveniently further comprise a support frame having an upper part and a lower part, the lower part providing the plurality of apertures.

In an alternative the support means comprises a support frame adapted to support the plurality of elongate elements substantially horizontally and substantially parallel with respect to each other.

The support frame may comprise a plurality of support members each having an uneven extemal surface and the elongate elements each comprise a loop formation on a first end for receipt of one of the support members when supporte thereon. The loop formations are conveniently formed by bending of the first end of each the elongate members.

Preferably the uneven external surface of each of the elongate members comprises a series of raised formations and recesses and the uneven external surface of each of the support members comprises a series of raised formations and recesses. Conveniently the series of raised formations and recesses are provided by a screw threaded formations.

The apparatus may further comprise retention means adapted to engage on each end of each support member when the elongate members are supported thereon. The retention means may comprise nuts adapted to be received on the screw threaded formations.

In an alternative the apparatus further comprises support members comprising at least two substantially parallel elements providing recesses adapted in use for receipt of the elongate elements, the support members being supported in use by the support frame.

In this case the parallel elements conveniently comprise formations upstanding therefrom which define the recesses. The upstanding formations are preferably substantially triangular, and may conveniently comprise a portion of expanded metal mesh, rolled flat and welded to elongate portions.

Thus, according to a third aspect of the invention, there is provided a method of treating articles comprising the method of suspending a plurality of articles in accordance with the first aspect of the invention and/or using an apparatus in accordance with the second aspect of the invention.

The treatment may for examples be painting, coating, electro-coating.

The invention will now be described, by way of example only, by reference to the accompanying drawings, wherein: FIGURE 1 illustrates a threaded bar as described in relation to the first embodiment of the invention; FIGURE 2 shows the threaded bar of Figure 1 engaged with a support frame, the support frame placed within an electro-coating processing tank ; FIGURE 3 is a step wise illustration of the manner in which the elongate elements may be engaged with the support frame; FIGURE 4 is an exploded view of a second embodiment of apparatus according to the invention; FIGURE 5 is a cross sectional view of part of the apparatus of Figure 4 ; FIGURE 6 is an illustrative plan view of the part shown in Figure 5; FIGURE 7 is an exploded view of a third embodiment of apparatus according to the invention, and FIGURES 8 & 9 are schematic views of a machine adapted to clean the intermediate frames of the apparatus of Figure 7.

Refeming first to Figure 1, there is shown an elongate member 10 comprising a threaded bar, conveniently such as that sold under the trade mark "Allthread". The tolu-eau 11 on the exterior surface of the bar 10 is a conventional helical thread, and runs continuously from one end of the bar to the other, although it will be appreciated that this need not necessarily be so.

A plurality of articles 12 are shown received on the threaded bar 10 through apertures 13 provided in a plate like part 14 of the brackets. The diameter of the apertures 13 is greater than the diameter of the threaded bar, such that the articles 12 may move freely relative to the threaded bar 10 when the plane of the apertures 13 is generally peyendicular with the axis of the bar 10.

However, as the centre of gravity of each article 12 does not coincide with the centre of the apertures 13, and thus is offset from the axis A of the bar 10, the articles 12, once passed over the bar 10 and released, fall under the action of gravity, to the position shown in Figure 1, where the plane of the apertures 13 is no longer peipendicular to the axis A of the bar 10.

In this condition, the threaded formations engage with the inner surface of the apertures 13, with the effect that the articles"catch"on the threaded parts such that movement of the articles 12 along the axis A is significantly impeded.

As partly illustrated by the articles 12 shown in dotted outline in Figure 1, the orientation which the articles attain allows a relatively large number of articles 12 to be supported in this manner relatively close to each other, but in such a way that the articles 12 will not contact one another as may be the case if the articles 12 were suspended freely as in the prior art.

Thus, where the threaded bar 10 is used as a support for articles during a coating process, such as, for example, an electro-coating process, a significantly increased density of articles per unit length of support bar may be attained when compared with the prior art, with significant cost advantages.

Referring next to Figure 2, there is shown a support means in the form of support frame 20 of generally conventional construction, but having an upper palt 21 and lower part 22 in the form of a perforated plate/section of grid weld or the like comprising an array of apertures.

As can be seen from Figure 2, the apertures are dimensioned such that the threaded bar 10 of Figure 1 may be introduced within the support frame 20 and maintained in position prior to lowering the support frame 20 and corresponding"wardrobe"23 into the electro-coating solution below the level 24 thereof.

As can clearly be seen, an upper section 25 of the threaded bar 10 remains clear of the solution and thus does not become coated during the process in contrast with the remainder of the bar 10.

There is provided towards the bottom of the bar 10 a threaded nut 26 which serves to prevent any possible downward movement of the articles 12 during the electro-coating process.

Referring now to Figure 3, the method by which the threaded bars 10 are introduced within the support frame 20 is shown. As can be seen, a threaded bar 10 is only partially"loaded"with articles 12 such that there remains an unloaded section 30 towards the top thereof.

The loading of the threaded bar 10 is performed whilst the threaded bar 10 occupies a generally horizontal condition, with the threaded bar 10 only being moved to a generally upright condition once the desired extent of loading has been completed. It is only when the threaded bar 10 is moved to such an upright condition that the articles 12"lock"in relation to the threaded bar 10 and in relation to each other to attain the regularly spaced and parallel extending conditions shown in Figures 1 to 3.

The partially loaded bar 10 is first introduced through an aperture in the upper palt 21 of the support frame 20, by generally upward movement as shown at position A. It will be seen that the bottom 31 of the bar 10 remains, at this point, clear of the lower part 22 of the support frame 20.

Subsequent to this, the bar 10 is moved generally downwardly so that the bottom 31 thereof passes through an aperture in the lower part 22, further downward movement of the bar 10 being prevented by the tlu-eaded nut/pair of locking nuts 32.

At this point, the bar 10 is held relatively securely in relation to the support frame 20, and the loading process may then be repeated for the desired number of threaded bars 10.

Once the support frame 20 has been fully loaded, the frame 20 is lowered into the electro-coating solution as shown in Figure 2, cuitent is passed to the threaded bars 10 via the upper perforated plate 21 and the electroplating process commence and undertaken in the normal mannes.

Referring now to Figure 4 a second embodiment of apparatus 40 according to the invention comprises a support frame 42 having a substantially rectangular base 43, a pair of substantially upright legs 44 and a lifting formation 45. The base 43 has an outer frame 43a and a mesh 43b within it, the reasons for which will become clear later. The legs 44 are perforated by holes 44a spaced apart along their length, the holes 44a on the two legs 44 being aligne.

The apparatus 40 further comprises a plurality, in this example six, of support members 46, in this case in the form of threaded bar, and a plurality of elongate members 47, in this case also in the form of threaded bar. The relative diameters of the holes 44a and support members 46 are such that the support members 46 are an easy sliding fit, but not a loose fit, in the holes 44a.

The support members 46 are supporte in generally horizontal orientation, and parallel with respect to each other, by the support frame 42 having been fed through holes 44a. In general pairs of support members 46 are fed through aligned pairs of holes 44a in the two legs 44 such that they are in a plane parallel with the base 43.

Each elongate member 47 comprises a loop formation 48 at one end thereof, formed by bending the end round and back on itself. The loop formation 48 is of such dimensions that it is loose fit around a support member 46.

In use the elongate members 47 are supporte by pairs of support members 46, with a support member 46 passed through the loop formations 48 to aid retention. When in this arrangement the support members 46 and elongate members 47 are only in contact with each other at the points where their respective thread formations are in contact 52, as shown in Figures 5 and 6. Hence the area of contact 52 is small and the force applied by the elongate members is sufficient to ensure a good electrical contact.

The apparatus 40 further comprises retention means 49 which in this example comprises nuts with an appropriate thread to engage on the support members 46. The nuts 49 are put in place on either end of each support member 46 once the elongate members 47 are in place.

Thus when a batch of articles 50, each having an aperture 51, is to be for example electro-coated the following method is adopted. An elongate member 47 is passed through the apertures 51 of some of the articles 50, and then placed in position on a pair of support members 46. This is repeated until all the articles 50 are in place, and then the nuts 49 are put in place.

The whole apparatus 40 is then lifted by means of the lifting formation 45 and lowered into an electro-coatillg tank (not shown), with the contents of the tank able to pass through the mesh 43b of the base 43. Electrical connection is made to the apparatus 40 either before or after immersion as appropriate. The coating process is then performed, the apparatus 40 lifted from the tank, the electrical connection removed and the articles 50 removed from the apparatus 40.

At this point those portions of the apparatus 40 which where fully within the tank, except those small areas of contact 52 between the support members 46 and the elongate members 47, and between the articles 50 and elongate members 47, will have been coated along with the articles 50. Thus in order to prepare the apparatus 40 for reuse it must be cleaned sufficiently for good electrical contact to be provided at similar but not necessarily identical contact points.

The cleaning of the threaded bars forcing the support members 46 and the elongate members 47, at least on the high points where electrical contact is made, is readily achieved by means of a rub down with by hand with an abrasive paper, such as emery or glass paper. This is both quick and cheap, and means that the apparatus 40 is ready for reuse in a matter of minutes. There is no need to clean the remaining portions of the apparatus 40, or indeed the remaining surface portions of the bars 46,47, as these areas are not required for electrical connections.

Referring now to Figure 7 a third embodiment of apparatus 70 according to the invention will now be described. The apparatus 70 comprises a support frame 42 as described above in respect of the apparatus 40, and for brevity it will not be described again. The apparatus 70 fuaher comprises a plurality of elongate members 71, in the form of threaded bar, with a C-shaped bend 71a formed at one end. An intermediate frame 72 a generally square or rectangular shape, comprises two opposite sides 73 of"saw tooth"construction, and two plane sides 74 spacing them part. The"saw tooth"shape of the sides 73 provide a plurality of recesses 73a for receipt of the elongate members 71, when they are laid across the intermediate frame 72 as shown in Figure 7.

This apparatus 70 ensures that the elongate members 71 are maintained at appropriate and even spacings even when the apparatus 70 is lifted into or out of a treatment bath.

The intermediate frame 72 is conveniently manufactured from threaded bar, with on the two"saw tooth"sides 73 a portion of expanded metal mesh, rolled flat and welded in place. The well defined edges of the recesses 73a provided in this way help to ensure good electrical contact is made between the elongate members 71 and the sides 73.

One a full intermediate fi-ame 72 has been loaded with articles 75 to be treated, the intermediate frame 72 is placed on aligned support members 46 of the frame 42. The use of threaded bar for the intermediate frame 72 helps to ensure good electrical contact between the intermediate frame 72 and the support members 46.

The apparatus 70 is then used as previously described with reference to the apparatus 40. After use however, the intermediate frames 72 may be cleaned ready for their next use using a machine 80 as illustrated in Figures 8 and 9.

The machine 80 comprises a frame 81 providing an elongate recess 82 for receipt of a"saw tooth"side 73 in order to retain it in position with respect to the machine 80. It funher comprises a pair of pivoting arms 83 upon which is mounted an axle 84, and a handle 86. Mounted for rotation with the axle 84 are a plurality of circular brushes 85.

A source of rotational energy is provided for the axle 84. This is conveniently a power-take-off pulley 87, which may be hand powered via a gearing arrangement, or powered for example by an electric motor.

To clean the"saw tooth"sides 73 of the intermediate frame 72, one side is put into the recess 82 with the recesses 73a aligned with the positions of the brushes 85. The power is provided to the axle 84 and once the brushes are rotating the handle 86 is pulled downwards towards the side 73, and the brushes 85 clean in the recesses 73a. The intermediate fi-ame 72 is then turned round and the other side 73 cleaned.

This machine 80 provides a very quick and cost effective method of cleaning the intermediate frames 72 and thus enables them to be used again rapidly.

The various members with uneven surfaces described above take the form of screw threaded bars. Screw threaded bars are simply selected as they are convenient and readily available. Ideally the threaded bars comprise Whitworth threads, or other course threads. However, any such members with sufficiently uneven surfaces, providing raised formations and recesses, to perfore in the same manner may be substituted. For example, bars with rings around the circumference, rather than a continuous spiral screw thread, would perform the function as well.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in tenus of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilise for realising the invention in diverse forms thereof.