This invention relates in general to fixing arrangements for fastening screen panels to their support structure for screening of materials such as mineral ores, and in particular to a fixing arrangement having multilayered contoured fixing means for snap-fit fixing of a screen panel on a support structure and also to a screen panel secured by such fixing means.

BACKGROUND TO THE INVENTION

Vibratory screening machines are frequently used for screening of materials such as mineral ores mostly in mining industries. The material to be screened is moved over the vibrating screen deck of a screening machine, the deck comprising of a number of screen panels put together and secured on the supporting frame. There are many types of screening surfaces available for such industrial vibrating screens. The selection of a screening surface for a particular duty depends on the screening aperture required and the nature of the work. The selection of size and shape of apertures, the proportion of open area, the properties of the material of the screening surfaces and flexibility of the screen surface are critical for a proper screening surface and therefore the performance of a screening machine. Screening surfaces are usually manufactured from steel, rubber, or polyurethane or combination of any of them, and can be classified according to how they are fixed to the screen. The screen panels are prone to wear due to the intrinsic abrasive nature of any screening process and thus they require replacement from time to time. From a maintenance point of view, however, this replacement should be as simple and quick as possible but the existing conventional fixing arrangements usually make the replacement process difficult and time consuming as they have individual elements that need to be removed and subsequently replaced.

Generally, in one such screen panel, there are provided a pair of semi- circular or half through cavities on its sides so that the next panel of similar type can be aligned to form a full cavity, which is used to fix the panel through bolt-and-nut to the support frame.

It is also well known that over a period of use, the screen panels get damaged or clogged or otherwise their functional efficiency is impaired. This requires stopping the operation or interrupting the screening and removing the impaired screen panel for replacement/repair as deemed necessary. The operation is time consuming due to the fact that the panel has to be freed from all sides by removing the fixing means and the replacement is again to be proceeded with by fixing along the sides of the panel.

Apart from such replacement being time consuming and labour intensive, careful monitoring is required for proper alignment. Moreover, every replacement means the fixing means are also to be taken out and re-fixed. Sometimes, the damaged ones are to be replaced. All this increases the inventory also.

Various types of both screen panels and fixing arrangements are known in the art. Some fixing means are found to be in the form of a series of protrusions in the frame of the screen panel itself and all these protrusions are to be integrally formed on the underside of the panel frame, which is a drawback. Further, it requires great skill to properly align these protrusions to match the holes or openings in the support frame.

A further drawback is that these protrusions are intended to tightly hold the screen panel to the support frame, but there is danger of these becoming loose on prolonged use due to the presence of continuous vibration, thereby affecting the efficiency of screening.

Further, the manufacturing of the screen panels with integrated fixing means increases the cost of production and engineering requirements. In yet another type of fixing means, adjacent sides of the screen panels are provided with specially designed contours which form locking arrangements when placed side-by side. The contours provided on the panel edges are complimentary, so that two adjacent panel sides match together and form a continuous screen surface. These are supported on the support structure with the inserts being provided in the holes. However, to hold the screen tightly on the support structure, a third element is required which has a specially formed outer edge matching the inner complementary shape of the insert. These together form the fixing means.

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However, this greatly increases the cost of manufacture and calls for precision engineering. Moreover, it is not possible to remove or replace any chosen damaged screen panel alone. The whole fixing unit is to be first removed and the required panels replaced and again re-fixed.

There are several other fixing means for screen panels, all of which have one drawback or the other. To the applicant's knowledge, there is no fixing means available in the prior art by which one can easily remove any chosen screen panel for repair or replacement.

U.S. Patent No. 4,596,503 refers to an expansion dowel assembly having an axially extending sleeve and a spreading element and having tongues pivotally displaceably connected to the sleeve and located one after the other along the axial direction of the sleeve. .

This construction is entirely different from the applicant's invention in terms of basic principle and is not suited for the purpose of applicant's objectives. It is totally irrelevant.

DE19849821 discloses an insert member having collapsible wing like portions. The insert has grooves 9 and 4 at 90 degree. The insert is to be pushed through are sent of grooves when the wing portions fold along the surface of the cylindrical outer surface and then it is twisted so that the wings are released and get locked the two grooves 9 and 4 are accordingly formed with precision. At the termination of the group 9, starts groove 4. This is also a totally different article and has nothing to do with the applicant's invention.

U.S. Patent No. 3,031,049 pertains to a fastening device for metal constructions for fastening together elements thereof or for fastening separate parts or accessories into the metal construction. It recommends the use of frames, ribs and fillets and especially formed fastening element.

As the name suggests, it is a fastening device for metal construction, whereas, the applicant's invention is for fastening device between a metal and a non-metallic construction in a vibrating structure. The Patent has nothing in common with the applicant's invention and is not suitable for the purposes for which the applicant's invention is concerned with.

U .S. Patent No. 5,379,912 is also irrelevant to applicant's invention in that it relates to an arrangement for connecting a cover panel for an electrical while the body structure of a vehicle using locking bolts etc.

U.S. Patent No. 1,647,783 is nearly 80 years old, filed in 1924. The screen panel and fixing arrangement of the instant invention cannot be even margined from this very old document. This U.S. patent is entirely different in that it refers to a non-resilient headed fastener having a neck and casting and an attaching member.

A more or less similar construction is disclosed in another 80 years old U.S. Patent No. 1,581,206 also filed in Dec. 1924. 7. U.S. Patent No. 4,984,798 :

In this Patent, there is disclosed an assembly and a display device for the playing pieces of two sided puzzle. There are spring mechanisms and side walls' on two complimentary sheets which is entirely different from applicant's invention.

Thus to the applicants' knowledge, there is no fixing means available in the prior art by which one can easily remove any chosen screen panel for repair or replacement.

Thus, there is a large need for a fixing arrangement or fastening arrangement that can be used in conjunction with screen panels for mining and quarrying industries so that the replacement process is simple, require less human intervention and also less time consuming, thus reducing the downtime of the plant. It allows attending to only the selected panels without dismantling the entire arrangement of panels.

The present invention meets the aforesaid long felt need.

OBJECTS OF THE INVENTION The primary object of the invention is to provide a fixing arrangement for fixing and removing screen panels to/from their supporting structure easily and quickly.

Another object of the invention is to provide a fixing arrangement that enables fixing or removal of individual screen panels without disturbing other panels of the screen deck.

A further object of the invention is to provide a fixing arrangement for snap- or press-fitting or removal of screen panels.

Yet another object of the invention of the invention is to eliminate expert manpower for fixing or removal of panels.

A still further object of the invention of the invention is to reduce spares inventory and downtime for repair/replacement of panels.

A further object of the invention is to provide a fixing arrangement which is cost-effective and easy to maintain. A further object of the invention is to provide a fixing arrangement wherein the layered construction of the insert member ensures that in the event of the panel coming out of the first layer of fixing, the multiple layers of fixing continue to provide a firm hold on to the insert member and in turn provide a reliable fixing means.

How the foregoing objects are achieved and the other aspects of the present invention will be clear from the following description which is purely exemplary and does not impose any limitation on the scope of the invention.

SUMMARY OF THE INVENTION

A fixing arrangement for snap-fit fixing of a screen panel on a support structure comprises of a plurality of male insert members fixedly provided on base plate in vertical orientation and a plurality of corresponding female bore holes provided on the underside of said screen panel. The base plate is adapted to be fixed to the screen deck frame or the screen sub-frame support structure of a screening machine for screening of mineral ore. The screen panel is snap-fitted or press- fitted to the base plate. In such instant, the male insert members exactly fit the corresponding bore holes and are locked therein.

The male insert members fixed vertically on the base plate have the following external contour profile geometries:

- a first elliptical contoured portion forming the top head of the male insert member;

- a recessed groove in between the first and the second elliptical contoured portions and imparting a caterpillar-like look to the male insert member;

- a second elliptical portion forming the bottom head of the insert member;

- a small neck contiguous with the second elliptical contoured portion;

- a straight cylindrical surface being smaller in diameter than the major diameter of the first and second elliptical portions; - an outer circular ring portion forming a collar, which has the largest diameter and helps in maintaining the required length of the insert member while fixing the member to the base plate; and

- a lower most cylindrical portion which guides the male insert member into the base plate.

The female bore holes provided on the underside of the screen panels have the following internal contour profile geometries:

First upper elliptical contoured portion forming the top head of the bore hole;

- a protruded portion in between the first and second elliptical contoured portions which imparts a caterpillar-like look to the bore hole;

- second lower elliptical contoured portion forming the bottom head of the bore hole;

- a small neck contiguous with the second lower elliptical contoured portion;

- a straight cylindrical portion being smaller in diameter than the major diameter of the first and second elliptical portions and) contiguous with the second portion; and

a counter groove circular portion with the cylindrical portion.

Both the bore hole and the male insert of the fixing arrangement have matching inner and outer contour profiles respectively, so that the male insert fits exactly into the bore hole.

When the panel is snap- or press-fitted on to the base plate, the lower collar on each insert member comes to rest on the circular counter groove circle of the bore hole and prevents any further insertion of the insert member upwards. Also at the same time, the top elliptical contour profile portion of the insert member fits onto the correspondingly contoured and matching inner top elliptical profile portion of the bore hole, the bottom elliptical contour profile portion of the insert member similarly fits onto the corresponding matching inner bottom elliptical profile portion of the bore hole, the recessed groove of the male insert fits exactly onto the corresponding matching protruded section of the bore hole, the neck of the insert member provides the member with a locking surface with the neck of the female bore hole and the straight cylindrical portion of the male insert member fits on to the corresponding cylindrical section of the bore hole.

The internal contour profiles of the bore holes exactly match the external contour profiles of the insert members and they are corresponding and complementary to each other. Also, the bore holes are positioned judiciously so that they fully match the positions of the insert members.

The screen panel is made of polyurethane, rubber or vulcanised or non- vulcanised elastomeric compound with metallic compounds embedded for strength and is adapted to be fixed to the support structure of a screening machine by the fixing arrangement as claimed as described hereabove.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The nature and scope of the present invention will be better understood from the accompanying drawings, which are by way of illustration of a preferred embodiment which is exemplary and does not impose any limitation on the scope of the invention. In the accompanying drawings,

Figure 1 is a perspective view of a fixing arrangement according to the present invention, i.e. base plate with the snap-fit multilayered caterpillar type insert members along with the corresponding screen panel. Figure 2 is a perspective view of the base plate with one positional arrangement of multilayered caterpillar type male insert members.

Figure 3 is a perspective view of the base plate with the multilayered caterpillar type male insert members in a different positional arrangement.

Figure 4 is a perspective view of a fixing arrangement i.e. base plate with the snap-fit multilayered caterpillar type insert members along with the corresponding screen panel in a different configuration .

Figure 5 is the front view of the snap-fit multilayer caterpillar type male insert member according to the present invention. Figure 6 is a sectional front view of the panel showing the female bore hole for the multilayered caterpillar type insert provided therein.

Figure 7 is a sectional view of the panel showing the snap fit multilayer caterpillar type male insert member fitted in the female bore hole; the insert being fixed to the base plate.

Figure 8 is an exploded view of the sectional view of figure 7 showing the assembly of the male insert member within the female bore hole on the panel and the base plate of the fixing arrangement.

DETAILED DESCRIPTION OF THE INVENTION

Having described the main features of the invention above, a more detailed and non-limiting description of a preferred embodiment will be given in the following paragraphs with reference to the accompanying drawings. The present invention primarily aims at providing improved snap-fit screen panel mechanism adapted for fastening a screen panel and more particularly, to a snap fit type fixing arrangement and its corresponding screen panel, secured by the snap-fit fixing system to an ore screening machine.

In the drawings, like reference numerals represent like features and the expressions "upper", "lower", "top", "bottom" and like expressions should be construed with reference to the orientation of the screen panel during use.

Furthermore, in the claims and the description the term "fixing arrangement" has been used but it should be understood, that such terminology includes similar terminologies like "fastening device", "fixing apparatus", "fixing means" and the like.

It is also clarified that the term "snap fitting" includes both manual operation and also press fitting operation by mechanical means and both come within the ambit of the present invention .

All through out the specification including the claims, the words "screen panel", "screen deck", "male insert", "bore hole", "fixing means", "screening apparatus", "base section", "fastening device" and so on are to be interpreted in the broadest sense of the respective terms and includes all similar items in the field known by other terms, as may be clear to persons skilled in the art. Restriction/limitation, if any, referred to in the specification, is solely by way of example and understanding the present invention .

Figure 1 shows a screen panel ( 18) and base plate (2) with the multilayer snap-type insert members (3) in accordance with a preferred embodiment of the present invention. A plurality of such screen panels is fixed to and supported by the screen deck frame to form the screen deck of a screening machine. In one embodiment of the invention the screen panels are cut in zigzag fashion to facilitate easy attachment of an adjacent screen panel.

The screen panels ( 18) are provided with bore holes ( 17) on their underside in predetermined locations. The panel is made of polyurethane, rubber or any form of vulcanized or non-vulcanized elastomeric compound with metallic compounds embedded in it for strength.

The base plate (2) is provided for fixing the screen panel ( 18) to the screen deck frame or the screen sub-frame structure of a screening machine. In this embodiment of the present invention, the fixing system ( 1), best shown in figure 8, has a plurality of fixing members or insert members (3) which are also called snap-fit type multilayered male insert members. These members are fixed vertically on the base plate (2) either through welding, or through bolting. Each base plate (2) extends along the length of the panel. A plurality of male insert members (3) is arranged in suitable configurations on the base plate (2).

Figure 2 is a perspective view of the base plate (2) with the multilayered caterpillar type male insert members (3) being provided in a particular positional arrangement. Here, the multi-layered male inserts (3) are present in a straight line. As mentioned earlier, the male inserts (3) are fixed vertically with the base plate (2) through welding or bolting.

Figure 3 is a perspective view of the base plate (2) with the multilayered caterpillar type male insert members (3) in a different positional arrangement. Here the male inserts (3) are spread out throughout the base plate. Figure 4 shows a perspective view of a fixing arrangement in accordance with another embodiment of the present invention. Here, the base plate (2) of screen panel (18) is provided with snap-fit multilayered caterpillar type insert members (3) along with the corresponding panel ( 18), where the panel edges are continuous along its border.

Figure 5 is the front view of the snap-fit multilayered caterpillar type male insert member (3) according to the invention. These male insert members are fitted vertically on the base plate (2) either in straight line or spread out throughout the base plate. When snap-fitted, the male inserts fit in the corresponding bore holes formed on the underside of the screen panel ( 18) in predetermined positions. The male insert (3) members have the following contour profile geometries : a. A first elliptical contoured portion (4) forming the top head of the male insert member (3). There can be a plurality of elliptical heads (4) both on the top and bottom portions depending on the configuration .

b. A recessed groove (5) in between the said first (4) and second (6) elliptical contoured portions and imparting a caterpillar-like look to the male insert member.

c. A second elliptical portion (6) forming the bottom head of the insert member.

d. A small neck (7) contiguous with the second elliptical contoured portion (6) .

e. A straight cylindrical surface (8) being smaller in diameter than the major diameter of the first and second elliptical portions (4, 6).

f. An outer circular ring portion (9) forming a collar, which has the largest diameter and helps in maintaining the required length of the insert member while fixing the member to the base plate. g. A lower most cylindrical portion ( 10) which guides the male insert member into the base plate.

The layered construction of the insert member (3) of the present invention ensures that in the event of the panel coming out of the first layer of fixing, the multiple layers of fixing continues to provide a firm hold on to the insert member and in turn provide a reliable fixing means.

Figure 6 is a sectional front view of the panel ( 18) showing the multilayered caterpillar type female bore hole ( 17). These bore holes are provided on the underside of the screen panel in predetermined positions to match the male insert positions.

The female bore holes ( 17) have been given the following contour profile geometries : a) First upper elliptical contoured portion ( 11) forming the top head of the bore hole.

b) A protruded portion (12) in between the first ( 11) and second ( 13) elliptical contoured portions which imparts a caterpillar-like look to the bore hole.

c) Second lower elliptical contoured portion (13) forming the bottom head of the bore hole.

d) A small neck ( 14) contiguous with the second lower elliptical contoured portion ( 13).

e) A straight cylindrical portion (15) being smaller in diameter than the major diameter of the first and second elliptical portions ( 11, 13) and contiguous with the second portion ( 13).

f) A counter groove circular portion ( 16) with the cylindrical portion It is clear from the accompanying drawings that the internal contour profile of the bore holes (17) exactly match the external contour profile of the insert members (3) and they are corresponding and complementary to each other. Also, the bore holes are positioned judiciously so that they fully match the positions of the insert members.

Now, how the male insert portion (3) fits into the bore hole ( 17) is explained with reference to figure 7. As clearly seen in this figure both the bore hole ( 17) and the male insert (3) of the fixing arrangement have matching inner and outer contour profiles respectively, so that the male part (3) fits exactly into the bore hole (17). The fixing mechanism of the male insert and bore hole ( 17) is achieved in the following ways : a) The top elliptical contour profile portion (4) of insert member (3) fits onto the correspondingly contoured inner top elliptical profile portion (11) of the bore hole of the screen panel .

b) The bottom elliptical contour profile portion (6) of insert member (3) similarly fits onto the corresponding matching inner bottom elliptical profile portion ( 13) of the bore hole (17).

c) The recessed groove (5) of male insert (3) fits exactly onto the corresponding matching protruded section ( 12) of the borehole on the underside of the screen panel.

d) The neck (7) of the male insert member (3) gives the member a locking surface with the neck ( 14) of the female bore hole ( 17).

e) The straight cylindrical portion (8) of the male insert member (3) fits on to the corresponding cylindrical section (15) of the bore hole (17). f) As the panel (18) is snap- or press-fitted on to the base plate (2) which is provided with a plurality of vertical male insert members (3), the insert members fit into their corresponding bore holes ( 17) . The lower collar (9) on each insert member (3) comes to rest on the circular counter groove circle ( 16) of the bore hole (17) and prevents any further insertion of the member upwards. In this position, the male insert member (3) is locked into the female bore hole ( 17) which it matches completely, thus completing the function of the fixing system (1) according to this invention.

Fixing system (1) ensures that perfect fitting is achieved in a simple manner by virtue of its unique construction. It should be understood from this construction and its operation that removal and replacement of the screen panels may be done easily without causing hindrance to other panels in a screening operation, even by unskilled persons. Figure 8 is a sectional view showing the exploded view of the male insert member (3), the female bore hole (17) on the screen panel ( 18), and the base plate (2) which comprise the fixing arrangement (1). The lower cylindrical portion (10) on the male insert member (3) guides the male insert member (3) while fixing it to the base plate (2) by means of suitable fixing means such as welding or bolting. The screen panel (18) is fixed to the base plate (2) having a plurality of snap-fit multilayer caterpillar type male inserts (3) fixed in vertical orientation.

The present invention has been described with reference to some drawings and a preferred embodiment purely for the sake of understanding and not by way of any limitation and the present invention includes all legitimate developments within the scope of what has been described herein before and claimed in the appended claims.