METAL CHAIN FOR CHAIN CONVEYORS

The present invention relates to a metal chain for chain conveyors, of the type indicated in the pre-characterising part of the main claim. A piece of metal chain in accordance with the pre-characterising part of the main claim is shown in the accompanying Figures 1A and 1 B. All known chains of the aforeindicated type present a gap between the opposing sides of one link and the preceding link. This gap is indicated by the letter G in Figures 1A and 1 B, and in the chains of best construction is currently between 1.5 and 2.8 mm. Gaps of 1.5 mm can however only be obtained in chains having large radii of curvature in their movement reversal parts.

These gaps between one link and the next in known metal chains cause numerous problems because projections provided on the base of the conveyed products can enter these gaps, to alter the operation of the conveyor and/or damage the conveyed product. This for example is the case with knurled projections provided on many glass bottles, which often interfere with these gaps to cause malfunction of the conveyor or damage to the bottles. These gaps are also dangerous during conveyor assembly and/or maintenance, as they constitute a danger in particular to the fingers of personnel carrying out these operations. Although the problem of eliminating the gap between the links of a chain is widely felt in the metal conveyor sector, no operator in this sector has succeeded in solving this technical problem during the last twenty years. An object of the present invention is to provide a metal chain in accordance with the pre-characterising part of the main claim which solves the aforestated technical problem, and in particular presents a surface between a link and the immediately adjacent link which when viewed from above is free of gaps, and hence improves the conveying of products by not damaging their base; a further object is to provide a chain which is of more reliable and easier

assembly.

These and further objects which will be apparent to an expert of the art are attained by a metal chain in accordance with the characterising part of the main claim. The invention will be more apparent from the accompanying drawings, which are provided by way of non-limiting example, and in which: Figures 1A and 1 B are respectively a side view and a top view of a piece of chain of known type; Figures 2A ₁ B ₁ C are respectively a top, bottom and side schematic view of a piece of chain according to the invention;

Figures 3A and 3B are enlarged schematic sections taken respectively on the lines A-A and B-B of Figure 1B.

With reference to Figures 2-3 these show a metal chain of the invention for chain conveyors, of the type comprising a plurality of metal links 1 (only four are shown in the figures), each link comprising a substantially plate-like metal body 1A defining a support surface 2 for the products to be conveyed, said body 1A presenting on a rear side 3 (with respect to the direction of advancement of the chain, indicated by the arrow F in Figure 2A) at least one first element 4 for connecting a link to the preceding link, said first connection element 4 comprising a first portion 4A substantially coplanar with said support surface 2, and a second portion 4B provided below said support surface 2, said two portions being shaped to house a part of a pin 6 connecting together two successive links of said chain. The body 1A presents in its front side 7, which is parallel to its rear side 3, at least one recessed seat 7A for housing the first portion 4A of the first connection element 4, and presents below the support surface 2 at least one connection counter-element 8 presenting at least two further portions 8A, each shaped to house a part of a pin 6 for connecting the links together, it also

presenting between said two further portions the second portion 4B of the connection element for another link of the chain.

The surfaces defining the rear side 3 and front side 7 of the body of said links when connected together are mutually rounded, in such a manner as to form a chain with a support surface which when viewed from above appears substantially continuous, without vertical slits between the opposing parts of the sides of a link and those of the immediately succeeding and preceding links. More specifically, that rear side 3 and front side 7 of a link which are immediately adjacent respectively to the respective front side 7 of a preceding link and to the rear side 3 of a successive link of the chain are rounded and shaped such that the slit created between said sides of the links is no longer vertical as in the known art, but extends as an arc such that the products conveyed by the chain encounter along the entire extension of the support surface of the chain a surface which, when viewed from above, appears closed and free of gaps.

This is ensured by the fact that, with the chain assembled, the upper edge B1 (Figure 3B) of the side of a link and the respective lower edge B2 of the immediately preceding or succeeding link appear superposed one on the other as shown in particular in Figures 3A and 3B. Advantageously, according to the invention, the upper edge B1 , substantially coplanar with the support surface 2 (Figure 3B) ₁ of the rear side (with respect to the chain advancement direction) 3 of a link M1 is superposed on the respective lower edge B2 of the front side 7 of the immediately succeeding (with respect to the chain advancement direction F) link M2. Advantageously, the radius of curvature R2 of the rounded lateral surface of the rear side 3 of a link M1 (Figure 3B) is greater than the radius of curvature R1 of the corresponding rounded lateral surface 7 of the immediately succeeding link M2, so that, if for any reason the conveyed products slide along the links (this

can for example be due to a narrowing of the conveyor), they encounter a facilitation surface for their passage from one link to the next. According to the invention, to prevent the presence of a vertical gap with the curved portion 4B of the connection element 4 of a preceding link, the side 10 (Figures 3A and 2B) of the recessed seat 7A of the front side 7 of a link is also rounded and is shaped such that the upper edge B3, substantially coplanar with the support surface 2, of said side 10, is superposed on the point of vertical tangency B4 of said curved portion 4B. In this manner, in the connection region between two links the slit created between the two links is no longer vertical, as in the known art, but extends as an arc such that the products conveyed by the chain always lie along the entire length of the chain support surface, a surface which when viewed from above appears continuous, closed and free of gaps. Advantageously, the connection element 4 and the relative counter-elements 8A are constructed in one piece with the body of the chain. Advantageously, a pressing process is used to form the curved surfaces along the adjacent sides of the links.

The link can be formed of any metal suitable for the purpose, for example of carbon steel (for example of C45 type), of standard steel (for example of AISI 430 type), or of austenitic steel (for example of AISI 304 type). Finally it should be noted that the aforedescribed embodiment is provided by way of example only, and that numerous variants are possible, all falling within the same inventive concept; for example the connection elements and respective counter-elements between one link and another could be of different type and/or shape and/or number than that illustrated. The chain conveyor could also be formed using a single chain or a plurality of mutually adjacent chains.

The surface 2 can also be provided with usual treatments or components for improving product entrainment.