GB2329645A - A method for maintaining a plurality of articles in spaced relationship - Google Patents

Abstract

A method for maintaining a plurality of articles in spaced relationship with each other, comprising inserting an elongate member having an uneven external surface, such as a threaded formation, into an aperture in each article, and 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. The method may be used when the articles are subject to a coating process, such as an electrocoating process.

Description

Title: A method for maintaining a plurality of articles in spaced relationship, and apparatus therefor.

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, for example a coating process such as powder coating or electro-coating.

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 electrocoating 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 hitherto 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.

Furthermore, in the case of relatively light weight articles, these exhibit a tendency to "float" during the electro-coating process due to agitation of the electro-coating fluid, and due to streams of air which are passed through the fluid during the process. In the case of such light weight articles, they may become dislodged from the hooks on which they are suspended, and fall from the conductive jig to which they are connected to the bottom of the electrocoating tank, thus necessitating regular draining and debris removal which clearly is undesirable.

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 carry 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 further object of the present invention to provide an improved method for electro-coating articles.

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 external surface into an aperture in each article, and 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, conveniently, on opposite sides of the aperture.

Conveniently, the external 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.

With such an arrangement, when the elongate member is in a generally horizontal condition, articles may be introduced onto the member (for example by hand) and moved freely along the axis of the member, but when the elongate member is moved to a generally upright condition, the interaction between the crests/troughs and the side of the aperture in each article is such that the article remains relatively firmly secured to the elongate member in the sense that movement of the article along the axis thereof is impeded.

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.

Clearly, in the case where the method is used for "suspending" articles for subsequent treatment, such as powder-coating or electro-plating, it is 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%.

It will be appreciated that a wide variety of threaded configurations may be suitable, although the applicants have found that threaded bar commercially available under the trade mark "Allthread" is particularly suitable, this being available in a wide variety of different diameters and thread profiles.

As discussed above, a common problem encountered during an electroplating process is that the jigs which carry the articles both before and after treatment themselves become coated or otherwise processed in the same manner as the articles, as the jigs carry current to the articles.

Thus, according to a second aspect of the invention, there is provided a method of electro-coating articles comprising procuring a generally elongate support member, attaching the articles to the support member, placing the support member in an electro-coating solution in a manner such that part of the support member remains above the level of the solution, and causing an electric current to flow through the support member to the articles.

The support member may be in a generally upright condition when the electric current is caused to flow through it.

Accordingly, the method of electro-coating articles may comprise the method of suspending a plurality of articles in accordance with the first aspect of the invention.

By allowing part of the support member to remain above the level of the solution, that part does not become coated during any stage of the process, and thus remains generally "clean".

Of course, the remainder of the support member (ie that part which is below the level of the solution) will become coated, and may thus become electrically insulated, and this coating will require removal by a physical, chemical, or heat induced process.

However, by allowing one part of the support member to remain clean, the support member, during cleaning of the remainder, may be held/secured by the "clean" part.

The method of electro-coating articles may comprise, prior to placing the support member in the electro-coating solution, engaging the support member with a support frame having upper and lower parts, the upper and lower parts having apertures therein suitable to receive the support member in a manner such that movement of the support member other than in a generally vertical direction is impeded.

The upper and lower parts may thus comprise perforated sheet metal plates, "gridweld", or other such material comprising an anay of perforations/apertures.

The support member may comprise, at a lower part thereof, stop means such as a nut threadedly received on the support member, a washer, or other generally radially extending protrusion, to prevent movement of articles below the stop means.

The support frame may be adapted to receive a pluralit > of support members, and conveniently, the support frame is loaded with such a plurality of support members away fi-om a processing tank, and placed within the processing tank only when the required number of support members have been engaged with the support frame.

The support frame is preferably lowered into the tank to an extent such that an upper part of each support member, protruding through the upper part of the support frame, remains above the level of the solution within the processing tank.

According to a third aspect of the invention, there is provided a method of treating apertured articles comprising inserting an elongate member having an uneven external surface through the apertures in the articles, and subjecting the articles to the treatment.

The treatment may be painting, coating, electro-coating, heating or otherwise.

Preferably, the uneven external surface is provided on the elongate member by a threaded formation.

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 aspect of the invention, FIGURE 2 shows the threaded bar of Figure 1 engaged with a support frame, the support frame and support member placed within an electro-coating processing tank, and FIGURE 3 is a step wise illustration of the manner in which the support members may be engaged with the support frame.

Referring first to Figure 1, there is shown an elongate support member 10 comprising a threaded bar, conveniently such as that sold under the trade mark "Allthread". The thread 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, in this example seat belt brackets, 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 may move freely relative to the threaded bar when the plane of the apertures is generally perpendicular with the axis of the bar.

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, the articles, once passed over the bar and released, fall, under the action of gravity, to the position shown in Figure 1, where the plane of the apertures is no longer perpendicular to the axis A of the bar.

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 along the axis A is significantly impeded.

As partly illustrated by the articles shown in dotted outline in Figure 1, the orientation which the articles attain allows a relatively large number of articles to be supported in this manner relatively close to each other, but in such a way that the articles will not contact one another as may be the case if the articles were suspended freely from a generally horizontally extending support, such as a line of hooks provided on a horizontally extending bar.

Thus, where the threaded bar 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, with significant cost advantages.

Referring next to Figure 2, there is shown a support frame 20 of generally conventional construction, but having an upper part 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 support member 10 of Figure 1 may be introduced within the support frame and maintained in position prior to lowering the support frame 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 support member 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 a threaded nut 26 which serves to prevent any possible downward movement of the articles 12 during the electro-coating process.

Referring finally to Figure 3, the method by which the support bars 10 are introduced within the support frame 20 is shown.

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

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

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

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

Once the support frame has been fully loaded, the frame is lowered into the electro-coating solution as shown in Figure 2, current is passed to the support bars via the upper perforated plate 21 and the electroplating process commenced.

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

Claims (10)

1 A method for maintaining a plurality of articles in spaced relationship with each other, comprising inserting an elongate member having an uneven external surface into an aperture in each article, and 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.

2 A method according to claim wherein 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.

3 A method according to claim 1 or claim 2 wherein the external surface of the elongate member comprises a series of raised formations and recesses.

4 A method according to claim 3 wherein the series of raised formations and recesses is provided by a screw threaded formation.

5 A method according to any one of the preceding claims wherein the difference between the diameter of the apertures in the articles and the diameter of the elongate member is no more than 20%.

6 A method according to any one of the preceding claims wherein the difference between the diameter of the apertures in the articles and the diameter of the elongate member is no more than 10%.

7 A method of coating articles wherein the articles are maintained in spaced relationship with each other during coating by use of the method in accordance with any one of claims 1 to 6.

8 A method according to claim 7 wherein the coating process is an electrocoating process.

9 A method substantially as hereinbefore described and/or as shown in the accompanying drawings.

10 Any novel feature or novel combination of features described herein and/or in the accompanying drawings.