Patent ID: 12234097

DETAILED DESCRIPTION

The present disclosure provides methods and apparatuses for manufacture of open ended belts made of an elastomeric matrix in which reinforcing members (e.g., filaments) are embedded in a longitudinal direction. The present disclosure also relates to such reinforced belts, whether provided as endless belts or continuous loop belts. Such belts can be toothed belts, flat belts, multi-v-ribbed belts, conveyor belts and similar products. Particularly useful are toothed belts which may require precise control of the tooth spacing or “pitch.” The elastomeric matrix can be a thermoplastic polyurethane (TPU) or any other suitable thermoplastic elastomer (TPE). The process may also be adapted for castable or thermoset resins or for a vulcanized rubber matrix. The matrix may be a combination of materials, such as a laminate or blend. The matrix material(s) may include any number of desirable ingredients, including for example, anti-oxidants, anti-ozonants, UV stabilizers, anti-microbial additives, process aids, softeners, fillers, friction modifiers, foamers, and the like.

The filaments (also referred to as fibers, multi-filament cords, and tension members) typically consist of a polymer material, such as a synthetic thermoplastic polymer material. The filaments may include a bundle of fibers, filaments or the like and may be twisted or cabled. A cord may be a monofilament or a bundle of filaments (.i.e. a yarn) or a twisted, braided, or cabled yarn or bundle of yarns and may be treated for adhesion or handling purposes. The term cable is often used interchangeably with the term cord. Herein, filaments will be used to refer to all types of multi-filament members, tension members, cords, or tensile cords.

The filaments disclosed herein (e.g., monofilament and multi-filament cords) may be made from a thermoplastic, synthetic polymer and may be extruded or spun as a single strand or multiple strands. The filament is preferably resistant to hosting bacteria and preferably hydrophobic depending on the material properties. When belt ends are terminated, exposed portions of such filaments would not be perceived as problematic in the food grade industry. More importantly, when the exposed belt ends are heated prior to fusing them together to make an endless belt, the thermoplastic filaments melt and retract into the belt matrix material, thus eliminating any chance of exposure or popping out during the end-welding process. It is believed the retraction is the result of relaxing the high-degree of orientation of the synthetic polymer molecules that was frozen-in during fiber formation.

Regardless of which synthetic polymer reinforcement member is used, field installations that currently require a skilled technician to be done properly could be achieved by those who have been trained but are less proficient at performing such a task. Likewise, belts requiring holes be placed across the width for drainage or suction applications would not need to be disposed of if such a stiffness member was inadvertently severed. In these instances a heat source would be applied to the area and the thermoplastic synthetic polymer filaments would melt back into the belt.

An example reinforced food grade belt100is shown inFIGS.1-3. The belt100includes a plurality of filaments112embedded in a first layer114(also referred to as a web114or a web material114). A plurality of teeth116are formed along one surface of the belt with land regions118between adjacent teeth116. The belt100includes first and second side surfaces120,122, first and second edges124,126, and first and second ends128,130. The belt100has a thickness T1for the first layer114, and a total thickness T2, as shown inFIG.2. A pitch line differential PLD may be defined as the distance of the centerline of filaments112from the first side surface120, as shown inFIG.12. The filaments112are spaced from second edge126a distance S1for a first filament, S2for a second filament, and so forth for each of the filaments112. A spacing SFis provided between each adjacent filament.

The filaments112may be configured as a monofilament12A having a single strand structure such as the filament112having a profile113and diameter D1as shown inFIG.9A. Alternatively, the filaments112may be combined as a multi-filament cord12B,12C as shown inFIGS.9B and9C, respectively. The pair of filaments112shown inFIG.9Bmay each have a diameter D2. The diameter D2may be smaller than the diameter D1such that both filaments112fit within a profile113that is the same as diameter D1shown inFIG.9A.

FIG.9Cillustrates another example multi-filament cord12C having three filaments112, each having a diameter D3. The filaments112shown inFIG.9Cmay fit within the same profile113that is equal to the diameter D1shown inFIG.9A. Other embodiments are possible that include four or more filaments112that together fit within the same sized profile113. Some embodiments may include ten or more individual filaments112, or hundreds or thousands of filaments, such as filaments as small as a few microns in diameter. The multi-filament cords disclosed herein may have a combination of filaments with different diameters and that fit within a profile113that is different from the diameter D1of the monofilament shown inFIG.9A.

The filaments112included with the multi-filament cords12B,12C may have various arrangements, such as being twisted, braided or arranged in parallel in a side-by-side arrangement. A multi-filament cord having the same profile113as the monofilament12A shown inFIG.9Amay have greater flexibility properties than a monofilament of the same materials. A multi-filament cord may have other advantages over a monofilament, although a monofilament has at least the advantage of a simple, single structure that may be easier to manufacture and handle. A multifilament yarn may be twisted (e.g., cabled if multiple yarns are used) with a number of turns per inch or turns per meter, which may optimize the balance between tensile strength and flexibility and handling.

The filaments112are shown in the figures having a circular cross-sectional shape. Other cross-sectional shapes may be possible, including, for example, rectangular or oval. Various cross-sectional shapes may be selected for their inherent properties, such as flexibility, rigidity, or the like.

The filaments112may comprise a polymer material such as, for example, a nylon-based material, an acrylic, a modacrylic, a polyolefin (such as polyethylene, polypropylene, and the like), vinylon, or a polyester. Other types of polymer materials may be used including, for example, a co-polymer (e.g., two or more types of nylon, or olefins, etc.), fluorocarbons, and hybrid strands such as, for example, nylon/fluorocarbon. In at least some examples, the filaments comprise a synthetic polymer. Synthetic, thermoplastic polymers generally are known to be meltable. In some example, one filament comprising such a synthetic, thermoplastic polymer can be connected to another such filament by heating the two filaments. It is also preferable that the material in the filaments can retract on heating, as well as to melt and flow together. It may also be advantageous if melting, followed by cooling or curing of the filament materials, creates a connection or bond to secure the two filaments (or ends of a single filament) together, or creates a connection or bond between the filaments and the web material114.

Generally, the filaments112comprise a material that has a melting temperature equivalent to or less than the melting temperature of the materials used to produce the body of the belt100(i.e., first layer114). The filaments112would, with such a melting point, effectively melt into the belt where the belt ends are connected together using a heat source as part of forming a continuous loop belt. The melting point of the filaments112, when provided at a level that is at or below of the melting point of the primary material of the belt, essentially permits the filaments112to always be embedded within the remaining portions of the belt so as not to be exposed to environmental conditions which may otherwise make the filaments112a host for bacteria or other conditions that would affect the belt's ability to meet food grade standards.

The first layer114(which may also be referred to as web material114) may comprise a polymer material such as, for example, thermoplastic polyurethane (TPU) or other suitable thermoplastic elastomer (TPE). A preferred filament material with a suitable melting point for use with TPU or TPE is a polyolefin. A preferred polyolefin is ultra-high-molecular-weight polyethylene (UHMWPE), which has tensile properties rivaling aramid fibers. Exemplary UHMWPE fibers and yarns for the filaments include those sold under the trademarks Spectra by Honeywell and Dyneema by DSM.

It may be noted that the filaments or cords may be twisted or not-twisted, depending on the needs of the belt application. The filaments may be used greige (untreated) or may be coated or treated, e.g., for improved adhesion, handling or the like.

Although a single layer of material for web material114is shown in the figures, multiple layers of material (e.g., first and second layers) may be used. In one example, multiple layers are formed separately and bonded together and/or one layer may be formed onto the other layer to make up the endless belt having the filaments112embedded therein. The filaments112may be embedded in any one of the layers or may be embedded between two or more of the layers. A variety of manufacturing methods and apparatuses may be used to create the belt100with the filaments112embedded therein. The method chosen is not critical to the resulting belt, as long as the method does not result in exposed cord on the edges or surfaces if food-grade applications are intended.FIGS.11-15, which are describe in detail below, are examples of some such systems, apparatuses and methods that may be used to make the belt100shown inFIGS.1-3or any of the other belts disclosed herein.

The teeth116are shown at spaced apart intervals along the length of the belt100. The teeth116may have any desired profile shape (e.g., the shape show in the side view ofFIG.2). The teeth116may be spaced apart any desired distance ST and have the land region118provided there between. The teeth116are shown having a relatively linear, straight construction along their length. The teeth116may extend between the edges124,126(i.e., an edge-to-edge arrangement). Alternatively, the teeth116may extend across only a portion of the width W1between the edges124,126, as shown inFIGS.4-6. Other embodiments may be free of any teeth116, such as the belt300described below with reference toFIGS.7and8.

The thickness T1typically is in the range of about 0.1 inches to about 0.5 inches, and more particularly about 0.1 inches to about 0.2 inches. The thickness T2is typically in the range of about 0.2 inches to about 1.0 inches, and more particularly about 0.3 inches to about 0.5 inches. Generally, the thickness T1is greater than the maximum diameter D1of the filament112shown inFIG.9A, and/or greater than the profile113of the multi-filament cords12B,12C shown inFIGS.9B and9C. Providing the thickness T1greater than the diameter D1and/or profile113makes it possible to completely embed the filaments112within the web114. In at least some arrangements, the diameter D1and/or profile113is in the range of about 0.01 inches to about 0.1 inches, and more particularly about 0.02 inches to about 0.05 inches.

The width W1is typically in the range of about 2 inches to about 48 inches, and may be sized anywhere therebetween depending on a variety of factors and criteria for the belt100. Other arrangements may include a width W1that is greater than 48 inches, such as between about 48 inches and about 84 inches. In at least some examples, the spacing SFbetween the filaments112is in the range of about 0.2 inches to about 2 inches, and more particularly about 0.3 inches to about 1.0 inch. The distance SFmay be equal between all of the filaments112. In some embodiments, the distance SFmay be variable, such as closer together adjacent to the edges124,126and spaced further apart towards the middle across the width W1. The distance SFmay be any desired size depending on the application and other properties for the belt100. The spacing SFmay vary significantly depending on, for example, the thickness T1, the materials used for the belt100, the number of teeth116and their spacing, and the type of material for the filaments112and first layer114.

The distance S1from the edge of the belt100to the first filament112is typically in the range of about 0.25 inches to about 2 inches, and more particularly about 0.4 inches to about 0.6 inches. The distance S2is equal to S1plus the spacing SFbetween the filaments. The distance to each additional filament112is equal to S1plus the spacing SFbetween the filaments.

FIGS.4-6illustrate another example food grade belt200that includes filaments212formed in a web layer, a plurality of teeth216with land regions218positioned therebetween, first and second side surfaces220,222, first and second edges224,226, and first and second ends228,230. The belt200may include many of the same or similar features and properties as the belts100described above. Some differences between the belt200and the belts100described above include, for example, the width, the number, size and spacing of the teeth216, and the number, size and spacing of the filaments212(i.e., SF, S1-Sx).

FIGS.7and8illustrate a further example food grade belt300that includes filaments312embedded in a web, first and second side surfaces320,322, first and second edges324,326, and first and second ends328,330. The belt300includes a web thickness T1, a Width W3, and filament spacing SF, S1-S2. The belt300is free of teeth116on either the first or second side surfaces320,322. The example belts100,200,300shown inFIGS.1-8are exemplary only of the variety of belt constructions and designs that can benefit from use of one or more filaments112,212,312when used in combination with materials layer114(or similar layer for belts200,300), maintains a food grade rating for the belts, particularly when free ends of the belt are connected together to form a continuous loop belt.

FIGS.10A and10Billustrate an example of an endless belt having ends128,130fused together to form a continuous or endless loop. The ends128,130are arranged adjacent to each other and a fusion device150operates to fuse the ends128,130together. In at least one example, the fusing involved melting the material of filaments112and layer114such that the materials flow together to create a unitary structure.FIG.10Bshows the endless belt after completion of the fusing, wherein the ends128,130are essentially eliminated due to the melting and retraction of the materials of filaments112and the melting of layer114and the subsequent solidification of those materials after the ends128,130are fused together.

Filaments that comprise a thermoplastic synthetic polymer may have different properties and resulting functionality as compared to conventional aramid materials such as Kevlar® which do not melt. The following Table I includes test data for a section of inventive reinforced belt that includes two twisted thermoplastic synthetic polymer cords (UHMWPE). Specimens were tested per a typical tensile test protocol using toothed insert grips. The specimens were held with three teeth at each end, with gauge length at approximately 5 inches. A preload of 2.0+/−0.3 pounds were applied. As noted in the results shown in Table I, the maximum load on average was 388 lbs., and a load at 2% extension on average was 37 lbs.

TABLE ILoad atInventiveMaximum Load2% ExtensionSpecimen No.lbs.lbs.139837238237338636Average38837

The results shown in Table I compare very favorably with similar test results from a conventional belt having two twisted aramid cords (e.g., Kevlar®) embedded therein. The test results for the conventional belt shown in Table II were tested per the same tensile test protocol using toothed insert grips. The specimens were inserted three teeth at each end, with gauge length at approximately 5 inches. A preload of 2.0+/−0.3 pounds was also applied. The maximum load on average was 298 lbs. The load at 2% extension on average was 27.3 lbs. Thus, a thermoplastic synthetic polymer cord with the same twist construction as an aramid fiber can be capable of withstanding higher loads.

TABLE IILoad atComparativeMaximum Load2% ExtensionSpecimen No.(lbs.)(lbs.)129327.0229324.5329725.8430429.2530329.8Average:29827.3

To test the weld, a similar tensile test was run on three example belts at three locations for each belt. The first location was a section of belt with no welds. The second location was at a butt weld. The third location was at a finger weld, with triangular fingers measuring about 30 mm wide at the base and about 70 mm in length (or height). The belt width tested in association with the data shown in Table III was about 3 inches with 3-4 cords in the belt. The results shown in Table III represent maximum load per cord for a comparative food grade belt having 1500-denier aramid cords, and the maximum loads per cord for two inventive belts, one with adhesive-coated UHMWPE cords and one with uncoated UHMWPE cords. The maximum load is a little smaller at the welds than in the unspliced portion of the comparative belt. Thus, a conventional belt spliced with either a butt weld or a finger weld would likely fail at the weld joint rather that at some location along the length of the belt away from the joint. On the other hand, for the inventive belts, the maximum load is greater at the welds that in the unspliced portion of the belt. Thus, an inventive belt spliced with either a butt weld or a finger weld would likely fail at a location spaced away from the joint rather that at the joint.

TABLE IIIMaximum LoadComparativeInventiveInventive(lbs./cord) ofbeltbelt coatedbelt uncoatedbelt and weldsaramid cordUHMWPE cordUHMWPE cordBelt149.0211.0194.0(2 cords per 1.5″)Butt Weld127.0225.0225.3(thru web)Finger Weld120.0225.3225.3(70 × 30)

One reason for trying adhesive-coated UHMWPE cord was the general reputation UHMWPE has for poor adhesion to most matrix materials including TPU. One of the unexpected results from the data shown in Tables I-III is that in spite of the suspected lower adhesion between the UHMWPE fiber and the urethane belt as compared to adhesion of aramid to the urethane belt, the maximum load of the belt with UHMWPE is higher than that for a belt with aramid (see Tables I-III). An even more surprising result of the test data relates to the maximum load of the butt weld and finger weld for UHMWPE verses aramid as represented in Table III. In the aramid sample, the maximum load is smaller for welded joints as compared to an unspliced section of belt, as is typically expected for any belt joint. However, for the UHMWPE welded joints, the maximum load is greater than for an unspliced section of belt. It is hypothesized that a possible reason for this improvement in maximum load for a welded joint when using is that the UHMWPE material retracts away from the weld when its melting point is neared or exceeded (i.e., the filaments melting point in this case is equal to or less than that of the urethane used for the belt). Thus, there is no discontinuity from the filaments right at the weld interface. In contrast the conventional aramid cord does not melt or retract so it probably weakens the interface at the weld. Thus, regardless of the reason, the use of a meltable polymer cord can result not only in better sealing of the cord within the belt, but also stronger fused or welded joints.

In the following, processes and methods are described to make a toothed belt out of thermoplastic polyurethane with synthetic polymer filaments as tension members, using the method and apparatus of the invention. It should be understood that the invention is not limited to these exemplary methods, materials, apparatuses or belt types.

A toothed belt410is shown inFIGS.11and12having three primary components: a base layer414(also referred to as a first layer or first layer material or first web material), a plurality of filaments412(also referred to as multi-filament members, tensile cords, and tension members), and a top layer415(also referred to a second layer or second layer material or profile layer). One or both of the top and bottom primary surfaces of the belt410could optionally include a woven or non-woven fabric, plastic film, or other surface treatment, although the belt410preferably comprises, in at least one embodiment, only food grade materials. The base layer414and top layer415could be the same material or could be two different thermoplastic materials. The base layer414and/or top layer415could be laminated from a plurality of layers of one or more materials or thermoplastic materials. The reinforcement, whether filament, multi-filament cord or the like, could be applied to the base layer414, the top layer415, or embedded between the base and top layers414,415.

The base layer414may be made of continuous extruded TPE or TPU having a flat surface on opposing sides, or may have teeth, or other desired belt profile, on one side and a flat surface on the opposite side. The top layer415may also be made of continuous extruded TPE or TPU having a flat surface on opposing sides, or may have teeth, or other desired belt profile, on one side and a flat surface on the opposite side. The base layer414and top layer415may be formed by known methods of extrusion forming or molding, such as the methods disclosed in U.S. Pat. Nos. 4,251,306 and 8,668,799, which are incorporated herein in their entireties by this reference, and which utilize a molding wheel and molding band adjacent about half of the circumference of the molding wheel to form a rotating profile molding chamber into which the profile material is extruded for continuous shaping.

The final thickness of the layers414,415is selected to allow embedding of the tension member at a predetermined pitch line differential (“PLD”). PLD is a measure of the thickness of the belt under the cord line, and is defined as the distance from the belt surface in the land region to the cord center line, as indicated inFIG.12.FIG.12is a partially fragmented bottom perspective view of the belt410shown inFIG.11. The land region418is the thin section of the belt located between any two adjacent teeth421(seeFIG.12).

Filament412is typically made of continuous filaments. The filament412may include a monofilament, or may include a multi-filament cord in which the individual filaments are twisted into a cord. In some embodiments, the filament412has an adhesive coating to bond. Filament412is parallel to the belt edges. Two or more different filaments412may be placed in the belt side by side simultaneously. For example, one kind of filament, or two or more filaments of equal or opposite twist (i.e., S and Z twist) may be used as the filament412. Preferably, the filament is fully embedded in the elastomer matrix without exposure at either side. An adhesive coating may be applied to the filament prior to cord laying in a separate operation or to the filament412or base layer414during filament laying in an integrated coating operation before the filament412contacts the elastomeric matrix material of one or both of the layers414,415.

Top layer415is typically made of a continuous TPE or TPU sheet of either the same material as the base layer414or a different material or different formulation. For example, the base layer414may be made of a relatively stiffer material for carrying high tooth loads, while the top layer415may be of a relatively softer material for higher flexibility, different coefficient of friction and/or for reduced noise and/or for reduced cost, or vice versa.

An example manufacturing process in accordance with the present disclosure includes the following steps with reference to the apparatus400as shown inFIG.11. The base layer414having the desired flat surface on both sides, or a flat surface on one side and a texture (e.g., belt profile) on an opposite side, is provided in the desired length and width from a spool409.

The base layer414is then fed around engaging roller404onto mandrel402as shown inFIG.11. The mandrel402and engaging roller404are rotated at a predefined speed for filament laying by a filament applicator in a wrap portion of the mandrel402and roller404. All the desired number of filaments412are laid at the same time, preferably in a parallel, lengthwise arrangement. The filament spacing may be uniform or in any other arrangement desired. In one example, sixteen filaments412are used. The filaments412are let off of a creel419which may have any desired number of spools408(only four are shown inFIG.11), and the filaments412are guided, for example, by guides422and423, and/or tensioned, for example, by tension rollers425and/or426, and finally fed into the filament applicator roller424.

The base layer414may be heated in advance of wrapping the base layer414onto the roller404and positioning the filaments412in contact with the base layer414. Various heating means may be used depending on the type of material of the filament412. For example, hot air blowers, radiant heaters, and the like may be used.

According to another embodiment, heated profile blades (not shown) may be positioned against the back side of the profile material to melt grooves into the profile material at a precise depth, width and temperature. The heated blades may have a profiled edge which forms a groove on the back side of the base layer414. Then the filaments412are provided from filament creel419and supplied to the roller404, which places the filament412into the groove at the desired depth to control the pitch line of the belt. The groove width and depth may be about the same as the filament diameter. The heated blade preferably acts like a plow as it forms a groove of molten material. A filament guide roller (not shown) may guide and press the filament412into the groove before the groove material re-solidifies. The distance between blade and filament guide roll, filament lay speed, and temperatures should be controlled such that the TPE material stays molten or at least tacky until the filament is embedded. The result is reinforced base layer414with filaments412fused thereon.

After completion of the filament laying operation, material for top layer415is applied to the base layer414with filaments412using an extruder411. The extruder411illustrated inFIG.11applies molten TPE or TPU material onto the base layer414and filaments412, and the molten material is pressed against the mandrel402, base layer414and filaments412to form belt410. Belt410may be taken up on spool420.

The process of pressing the material of top layer415onto mandrel402may result in formation of a belt profile in the top layer415. By belt profile it is meant a belt surface configuration adapted to engage a pulley or sprocket in driving relation thereof in a belt drive system. In a friction driven belt drive system, for example, the belt profile may be flat, or V-shaped, or multi-v-ribbed, while in a synchronous or positive drive system, the belt profile may be a series of evenly spaced transverse teeth or angled or helical teeth. In other arrangements, the mandrel402forms a flat, smooth surface on the top layer415.

The process parameters of lamination speed and heat input should be adjusted such that only a thin skin of melting occurs on both surfaces without the material melting through and losing its shape. Even pressure along the whole length of the laminating rollers is also advantageous and may be facilitated by use of an elastomeric roll, although steel rollers provide better heat transfer. The optimum heating and melting amount permits the top layer to fully bond to the base layer and filaments, flowing around the portion of the filament not yet embedded, but not disturbing the pitch line and position of the filament.

The open-ended belt may be cut to a desired length and joined by known methods to form an endless belt, and in the case of a toothed belt, with the desired number of teeth. Fusion of the ends may be, as non-limiting examples, by thermal fusion by heat treatment or ultrasonic welding, direct adhesion, or thin film or adhesive tape, or clamps, with butt joint or finger joint, or combinations thereof.

Any process in which the belt may be wholly sealed from the intended use environment as may be used for food service or other “clean belt” applications requiring cleaning, sterilization or the like (referred to as “food grade” applications).

Separate manufacture of the base layer414and the top layer415has a number of advantages over prior methods where everything was formed and assembled on the same apparatus. Separate manufacture allows base and top layer materials to be made at optimum speeds for extrusion, generally much faster than possible when filament laying and/or laminating is done at the same time. Separate manufacture also permits much easier set up of the belt making system ofFIG.11, and for a much simpler design of that apparatus and lower capital cost. In particular, a complicated extruder with crosshead die for multiple filaments and a conventional molding pressure band and its associated drive system are not necessary. Set up times may be significantly reduced and filament material utilization may be improved.

FIGS.13and14illustrate additional example methods or systems500,600, respectively. In a first step shown inFIG.13, filament(s)412are laid onto a smooth mandrel402′ and then coated with matrix material from extruder411which is then cooled under the pressure band452to form carcass477, which is a flat film with filament embedded right at the surface. The filaments412may be multiple parallel filaments412as described for other embodiments. In a second step, shown inFIG.14, profile mandrel402replaces smooth mandrel402′, in order to make a profiled belt410. Of course, the smooth mandrel may be used again if a flat belt is to be made. The extruder and pressure band section are now used to form the profile layer while the flat carcass477is fed into the pressure band section at the same time. Thus, the flat carcass, containing the tensile filament, is laminated to the profile layer as the profile layer is formed. The surface of the carcass at which the filament412is just embedded is preferably placed against the profile layer to seal the filament412therein. The first step is found to provide a flat film with very good control of the filament position, since the filament412is laid on a smooth mandrel. The resulting belt410has very good filament control, and the PLD may easily be controlled by the positioning of the pressure band. According to another variation, this two-step process could be carried with a laminating roller suitable arranged close to the mandrel or forming roller, instead of the pressure band shown in the figures.

Alternately, this or many of the other variations could be achieved by two or more passes of material(s) through apparatus similar to that described herein. A first pass, for example, could make the carcass, whether toothed or flat. A second pass could form and/or laminate a top layer onto the carcass. Another pass could weld or glue or fasten on profile parts, such as belt teeth for driving the belt on pulleys, or other objects, profiles, holders or such features which might ultimately be used for transporting items or material handling or the like.

Another example system and related method700of forming a reinforced belt410is shown inFIG.15. The belt410has a base layer or base layer414formed onto a plurality of filaments412. The belt410is formed using a straight through die process. The die may be attached to some type of extruder411. The system700may include rollers402,404as in a calendar method of forming a reinforced belt.

Filament412is typically made of continuous filaments. The filament412may include a monofilament, or may include a multi-filament cord in which the individual filaments are twisted into a cord. In some embodiments, the filament412may have an adhesive coating to bond. The filaments412are let off of a creel419which may have any desired number of spools408, and the filaments are guided and/or tensioned by tension roller425, and finally fed into the rollers404and424.

Filament412is applied and fused to layer414in a continuous process during formation of the layer414. Layer414is typically made of a continuous TPE or TPU sheet of material. A flow of the matrix material used to create layer414is fed between engaging roller404and mandrel402by an extruder411, as shown inFIG.15.FIG.15Ashows a cutaway of the resulting belt410with filaments412embedded in the layer414. Belt410may then be taken up on spool420. One or more of rollers402,404may be profiled to make a desired profiled belt instead of the flat belt shown. Other systems may include a cross-head die in place of the rollers402,404.

FIG.16is a flow diagram showing steps of an example method800in accordance with the present disclosure. The method800may be directed to a method of manufacturing a reinforced food grade belt. The method800includes, at step802, providing a plurality of thermoplastic synthetic filaments. Step804includes providing a thermoplastic elastomeric belt body material. At step806, the method includes embedding the filaments in the belt body material. The step808includes forming the body material into a desired belt profile.

The method800may be continuous, resulting in long-length belting. The method800may include cutting the belting to a predetermined length and fusing the ends together to form an endless belt. The plurality of filaments may be melted during the fusing step. The plurality of filaments may be arranged in parallel and extend along a length dimension of the belt. The plurality of filaments may include a meltable synthetic polymer. The plurality of filaments may have a melting point that is approximately equal to, or equal to or less than, a melting point of the belt body material. The filaments may have a melting point that is within 50° C., or within 40° C., or within 30° C., or within 20° C., of a melting point of a belt body material. Each of the plurality of filaments may include a monofilament or a multi-filament cord. The filaments may be directed into the first layer material with a die during extrusion of the first layer material.

FIG.17is a flow diagram showing steps of an example method900in accordance with the present disclosure. The method900may be directed to a method of manufacturing a continuous loop reinforced food grade belt. The method900includes, at step902, providing a plurality of meltable synthetic filaments arranged in parallel. Step904includes extruding a layer material to form the belt with the filaments embedded therein, the belt having opposed free ends with the filaments exposed at the free ends. Step906includes positioning the free ends adjacent to each other. Step908includes melting the filaments and layer material at the free ends to connect the free ends together to form the continuous loop reinforced food grade belt. The filaments and layer material may include food grade polymer materials. Extruding the layer material may include extruding a first layer material onto the filaments, and extruding a second layer material onto the layer material.

The systems and methods described herein could also be used to make other forms of belting or belt-like articles, such as tracks for use in track drive systems for various types of track-driven vehicles.

The reinforced belts and related methods of manufacture disclosed herein may provide one or more of the following improvements/advantages over conventional solutions:The ability to form a continuous loop, reinforced belt that is food grade compliant after connecting the free ends of the belt together to form the loop, by preventing any portions of the reinforcing filaments from being exposed after the connection is completed.The use of reinforcing members that can provide increased strength to the belt at the weld joint as compared to portions of the belt spaced away from the joint.The ability to more easily create food grade weld joints in the field with none of the filaments exposed.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods, and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. The invention disclosed herein may suitably be practiced in the absence of any element that is not specifically disclosed herein.