Abstract:
An on-machine-seamable industrial belt and method of forming an on-machine-seamable industrial belt including the steps of providing a base structure having first and second edges, providing a seam connecting the first and second edges, and laminating a layer onto the base structure and the seam.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to on-machine-seamable industrial belts and methods of making industrial belts. Specifically, the present invention relates to seamed laminated belts for use in industrial applications.  
         [0003]     2. Description of the Prior Art  
         [0004]     Industrial belts referred to herein may include those used as conveyors and conveyor belts used in the food processing industries, belts used for the product of medium density fiberboard (MDF), and belts used in the production of nonwovens, i.e. carding, lapping, and other industrial applications. Typically these belts are impermeable which, for example, in the food processing industry is useful in preventing the adherence of bacteria and promotes ease of cleaning of the belt.  
         [0005]     Traditionally, belts used in these industries or for these application have either been formed endless, by for example endless weaving, or alternatively a seam such as a clipper seam is attached to the two cross-machine (“CD”) edges of the belt in order to make the belt endless. Another approach which is sometimes used to form an endless belt is brazing or welding the cross-machine edges of the belt together. As will be readily appreciated, the brazing requires the belt to include metal portions that can be joined together. Yet a further approach for making a belt endless is the joining with a pin seam wherein the two CD-edges of the belt are made endless by interdigitation of loops formed from the machine direction (“MD”) yarns on the edges of the belt and inserting a pin or pintle there through to hold the interdigitated loops together.  
         [0006]     The clipper seam mentioned above is a very common device used to seam a belt into an endless form. This variety of seam comprises a plurality of generally U-shaped clipper hooks, which are installed in an alternating relationship on the CD-edges of typically a corrugator belt, so that, when the two CD-edges of the belt are brought together, they may be interdigitated to define a passage through which a lacing cable or pintle may be directed to secure one edge to the other. The individual clipper hooks are of stiff metal wire, and have two parallel members which are separated from one another by an amount substantially equal to, or slightly less than, the thickness of the belt, and which have mutually directed barbs, so that, when pushed onto the edge of the belt, they are not readily removed. The two parallel members, which are on opposite sides of a CD-edge of the belt after the clipper hook has been installed, and which lie snugly against the opposite surfaces thereof, may be of equal or different length, and may therefor extend the same or different amounts longitudinally from the CD-edge of the belt.  
         [0007]     Mechanical fasteners of other types are sometimes used. There are tapered overlays or joints for fastening or seaming, such as those used by Siegling GmbH, Hannover, Germany (www.siegling.com) and Habasit AG, Basel, Switzerland (www.habasit.com) on their belts.  
         [0008]     Other seams may be sewn on which involves a woven web or spiral lace sewn onto both CD-edges of the belt with the woven web or spiral lace includes connecting loops. Alternatively, the woven base structure of the belt may contain connecting loops. In either event the connecting loops are meshed together to form the seam through the application of a pintle through the interdigitated loops.  
         [0009]     However, these heretofore known methods of seaming have certain drawbacks for certain applications. One aspect of certain belts is the desire to ensure a smooth and uniform surface for the product being conveyed. One method of providing such a surface is for lamination of a layer or layers of material onto one another or onto, for example, a woven or knit base structure. However, the seaming methods described above do not always allow for a smooth surface. Those skilled in the art will appreciate that the seaming of laminated structure presents its own problems in terms of uniformity, impermeability, wear, and fatigue resistance.  
         [0010]     One particular problem that affects laminated belts is that the lamination material, such as polyurethane or silicone films, may delaminate from the base structure. This delamination may often be caused by the method or the means employed for joining the two edges of the fabric.  
         [0011]     This problem has proven to be particularly troubling in the lamination or coating of belts useful in the conveyance of foodstuffs. These coatings are often provided with certain useful attributes including antibacterial features or a particular resistance to adherence of the material deposited thereon. As can be imagined, the delamination of antibacterial coatings from a conveyor for food stuffs provides a two fold problem of contamination of the foodstuff by the delamination as well as a breakdown in the antibacterial effect. Accordingly, preventing this delamination is of great utility to the food processing and packaging industry.  
         [0012]     Another issue is that since seaming methods do not address openings in the belt made by the seaming technique itself, such seams provide an opportunity for foodstuffs or contaminants to become imbedded in the seam and thereby nullify much of the antibacterial and cleanliness properties of the belt, that is otherwise impervious.  
         [0013]     Obviously, there are ways to provide seamable fabrics for use in industrial applications, with the foregoing being set forth merely as examples. However, as with anything, there is always a desire to improve on or provide an alternative to what has been done previously. Seamable fabrics are no exception. The present invention is directed to resolving the shortcomings of the known seaming methods.  
       SUMMARY OF THE INVENTION  
       [0014]     Accordingly, the present invention is both a seamed industrial belt, and the method of making it.  
         [0015]     One object of the present invention is to provide a laminated seamable belt that substantially resists delamination.  
         [0016]     It is another objective of the present invention to provide a means of joining a laminated belt utilizing a set-in seam.  
         [0017]     It is a further objective of the present invention to provide a laminated belt including an extruded seam spiral.  
         [0018]     One aspect of the present invention is directed to an on-machine-seamable belt including: a base structure having a first and second edge; one or more layers of material laminated to the base structure; and a seam for seaming the first and second edges together to form an endless belt, wherein a laminated material layer is attached to the base structure over and covering the seam. A second layer can be laminated on the other side of the base extending below the seam. The belt further includes one or more flaps cut from the layers laminated to the base structure with the flaps providing access to the seam and protecting it from exposure. In this context, “base structure” can either be a component of the belt, or the entire belt prior to the laminated material layer or layers being applied.  
         [0019]     A further aspect of the present invention is directed to an on-machine-seamable belt including a base structure having a first and second edges, a layer laminated to the base structure and over and preferably also below a seam formed of a set-in seam attached to the first edge of the base structure and set of seaming loops formed on the second edge of the base structure, wherein the layers laminated to the base structure protect the set-in seam and prevent the material carried thereon from passing through the seam  
         [0020]     Yet a further aspect of the present invention is directed to an on-machine-seamable belt including a base structure having first and second edges, a layer laminated to the top and bottom surfaces of the base structure, and an extruded spiral attached to each of the first and second edges, wherein the laminated layer have a shorter length than the base structure, and wherein the laminated layers abut edge to edge when the extruded spirals are interdigitated.  
         [0021]     As to all of the embodiments, the method in general involves forming an on-machine-seamable belt which includes the steps of providing a base structure having first and second edges, providing a seam connecting the first and second edges, and laminating a layer onto the base structure and in most embodiments at least above and also preferably below the seam.  
         [0022]     The present invention will now be described in more complete detail with reference being made to the figures identified as follows. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0023]      FIG. 1  is a cross-sectional view of a seamed belt according to one aspect of the present invention;  
         [0024]      FIG. 2  is a cross-sectional view of a seamed belt as shown in  FIG. 1  after seaming;  
         [0025]      FIG. 3  is a top view of a seamed belt according to a further aspect of the present invention;  
         [0026]      FIG. 4  is a cross-sectional view of a seamed belt shown in  FIG. 3 ;  
         [0027]      FIG. 5  is a cross-sectional view of a seamed belt according to a further aspect of the present invention;  
         [0028]      FIG. 6  is a cross-sectional view of a seamed belt according to a further aspect of the present invention;  
         [0029]      FIG. 7  is a top view of the seamed belt shown in  FIG. 6 ; and  
         [0030]      FIG. 8  is a cross-sectional view of a seamed belt according to a further aspect of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0031]     As described above, there are a variety of applications in which a fabric or belt may act as a conveyor. The specific examples previously described involved applications for transporting a variety of items including, for example, foodstuffs and in the production of MDF and nonwovens. The present invention is, however, not so limited and may be applied to any use requiring a seamed and laminated belt in industrial applications.  
         [0032]     One aspect of the present invention can be seen with reference to  FIGS. 1 and 2 . In  FIG. 1 , a belt  10  having an integrated seam  12  is shown. The seam has been joined to form an endless belt. The integrated seam may be formed of a standard loop seam wherein the MD yarns of the base form the loops. Alternatively a spiral is attached to form a spiral seam, such as an in-line spiral seams as known to those of skill in the art, or any other seam construction suitable for the purpose may be used. In  FIG. 2  there is shown a loop seam  14  seaming the two edge portions  16  and  18  of the belt  10  together in the cross machine direction (“CD”) using a pintel  15 . Overlying base structure  12  is a laminate  20  which is at least above the seam  12  and preferably also below it. The laminate  20  includes a cut  17  exposing at least a portion of the loop seam  14  and the pintle  15 .  
         [0033]     In production of the belt  10 , according to one aspect of the present invention, the base structure  22  including the seaming loops of the loop seam  14  are formed and joined using for example a pintle  15  to form an endless belt  10  as shown in  FIG. 1 . A protective covering, not shown, is placed over the seam to prevent the adherence of a coating or laminate thereto. The endless belt  10  is then laminated with a film  20  to form an endless belt. Examples of coating or lamination material may include coPET and PET films, or a combination of coPET or PET films, polyurethane, or other suitable materials known to those of skill in the art. The endless belt is then cut ( 17 ) along the seam  12  above the seam (and below the seam if both sides were laminated) to create a flap(s) of laminate material and to allow for removal of the pintle  15 . At this point the protective covering which was installed to protect the seam is also removed. Following removal of the pintle  15 , the belt may then be installed on a machine. The seam  12  and pintle  15  allow for on-machine-seaming of the belt  10 . The flap of the laminate material, created by the cut(s)  17  protects the seam  12  and the resultant belt will have a substantially uniform cross-section for the entirety of the belt  10 . After installation and connection of the edge of the belt via the seaming means, localized heat and in some cases pressure is applied to the seam area to fuse or “laminate” the film to the base structure in the seam area.  
         [0034]     A further aspect of the present invention can be seen with reference with  FIGS. 3 and 4 . According to this aspect of the present invention, a base structure  22  may be formed by for example weaving. On one or both edges of the woven base structure  22  seaming loops may be formed by weaving MD yarns back into the base structure to form seaming loops along the cross machine direction edge of the base structure  22 . Alternatively, a seaming spiral may be inserted into the base structure at one or both edges. As a further alternative on an edge of the base structure  22 , a set-in seam  24  may be attached. The set-in seam  24  may be attached to the base structure  22  by for example welding, sewing or gluing of the set-in seam  24  to the base structure  22 . The set-in seam  24  includes on the edge not attached to the base structure  22  a series of loops  26  that can be interdigitated with the loops formed on the edge of the base structure  22 . These loops can then be joined by use of a pintle to form an endless fabric.  
         [0035]     The base structure  22 , seaming loops, seaming spiral and set-in seam  24  or whatever combination thereof can then be laminated thereabove and preferably therebelow. Again, prior to lamination the seaming loops, etc., must be protected to prevent adhesion of the coating or laminate film applied thereto. The coating or lamination will provide cohesion and uniformity between the belt and the seam area. Again, following coating or lamination the laminate may be cut to allow for on-machine-seaming of the belt. Alternatively, the belt may be laminated without being formed endless, and following interdigitation of the loops and insertion of a pin therethrough during installation, the edges of the laminate will abut against one another when formed endless so that a continuous surface is presented.  
         [0036]     A further aspect of the present invention is shown in  FIG. 5 .  FIG. 5  depicts a base structure  22  having a laminated layer  20  formed over and under the base structure  22 . On the edge of the base structure  22  and attached thereto is a seaming spiral  28 . The seaming spiral  28  is attached to the base structure preferably after lamination; however, the seaming spiral  28  may also be attached to the base structure  22  before lamination. Each edge of the base structure  22  may include a seaming spiral  28 , which when brought together and interdigitated can be joined by placement of a pintle through the orifice  30 .  
         [0037]     Yet a further aspect of the instant invention is shown in  FIG. 6 . In  FIG. 6 , a base structure  22  having a laminated layer  20  formed over and under the base structure  22 . Attached to the end of the base structure and attached thereto is a edge piece  32 . The edge pieces are formed having a series of tabs  36  as shown in  FIG. 7 . Each tab includes a hole  34 . In use, the edge pieces  32  are formed on both CD edges of a conveyor, interdigitated, and a pintle is set through the holes  34  of the tabs  36  forming and seamed endless conveyor. The interdigitated tabs  36  create a substantially uniform surface that prevents food stuffs and the like from migrating through the conveyor. The edge piece  32  is formed on the base structure preferably after lamination of layers  20 , however, the edge piece may also be formed on the base structure prior to lamination. In the embodiment shown in  FIG. 6 , the lamination is stopped a few millimeters before the edge of the base structure  22  to accommodate the edge piece  32 .  
         [0038]     In yet another embodiment shown in  FIG. 8 . the edge piece  32  is shown with a height no greater than the base structure  22 . The edge piece  32  is attached to the base structure  22  and the lamination layers  20  extend over the edge piece  32 . In such a configuration, the laminated layers  20  further assist in presenting a continuous and smooth surface to any material deposited on the conveyor.  
         [0039]     Accordingly, by use of one or more of the forgoing aspects of the present invention a belt may be formed which does not suffer from certain of the undesired attributes of those heretofore known to those of skill in the art. Simultaneously, the present invention provides a laminated structure that prevents particles from contaminating the belt particularly in the seam area, resists bacterial development, reduces the risk of delamination associated with for example clipper seams all while providing a readily seamable belt.