Reinforced food grade tape and method of manufacture

Abstract

A continuous looped reinforced food grade belt comprising a plurality of extruded filaments comprising a meltable synthetic polymer, and at least one matrix material in which the filaments are embedded. The matrix material comprises a food grade polymer, and the matrix material and filaments form a length of belt having opposing first and second end portions. The first and second end portions are fused together to form a continuous looped belt, and no filaments are exposed to the belt environment.

Description

Technical Field

[0001] This invention generally relates to reinforced belts, and more specifically to reinforced food-grade belts and related manufacturing methods. Background Technology

[0002] Existing technology description:

[0003] Conventional continuous extrusion methods for forming thermoplastic elastomer (“TPE”) or thermoplastic polyurethane (“TPU”) reinforced tapes use aramid reinforcing elements (such as fibers, filaments, and cords) for dimensional stability, which are susceptible to bacterial contamination when exposed. These reinforcing elements are often exposed due to secondary manufacturing processes such as forming endless tapes or continuous loops (i.e., cords often protrude at or near the interface of the mating ends of the tape).

[0004] In other methods, unreinforced food-grade belts are used to avoid exposing materials, which would be considered unacceptable in the food industry. These types of unreinforced food-grade belts are typically composed solely of polyurethane and lack reinforcement. Similarly, these belts are prone to stretching during use, causing manufacturing downtime, thus halting the conveyor line, and requiring reprocessing to tighten any excessively slack sections.

[0005] Therefore, there is a need for an improved food-grade belt that is both reinforced and less susceptible to bacterial growth in order to meet food-grade safety protocols. Summary of the Invention

[0006] This invention relates to reinforced food-grade belts, revolving belts, and related manufacturing methods. By replacing the current aramid fiber strands in existing food-grade belts with filaments (e.g., monofilaments or multifilament strands) comprising optional materials, particularly meltable thermoplastic materials, the belt can still be reinforced while significantly reducing the opportunity for exposure to any materials that could allow bacterial growth on the belt, which would prevent the belt from being considered food-grade. The filaments can be made from synthetic polymers with a melting temperature equal to or lower than that of the primary material used to produce the belt. This allows the new filaments to be efficiently melted into a belt when joined together at the ends with a heat source to form a continuous loop, thus eliminating any opportunity for exposure to any portion of the belt that would prevent it from being considered food-grade.

[0007] One aspect of the present invention relates to a method for manufacturing reinforced food-grade belts. The method includes providing a plurality of thermoplastic synthetic filaments, providing a thermoplastic elastomer belt body material, embedding the filaments in the belt body material, and forming the body material into a desired belt profile.

[0008] This method can be continuous, forming long strips. The method may include cutting the strip to a predetermined length and fusing the ends together to form a revolving strip. Multiple filaments can be melted during the fusing step. The multiple filaments can be arranged in parallel and extend along the length of the strip. The multiple filaments may contain a meltable synthetic polymer. The melting point of the multiple filaments may be equal to or less than the melting point of the strip bulk material. Each of the multiple filaments may contain a single filament or a multi-filament strand. The filaments can be introduced into the first layer of material using a die during the extrusion of the first layer. The desired strip profile can be a flat surface.

[0009] Another aspect of the invention relates to a continuous annular reinforced food-grade belt. The belt comprises a plurality of extruded filaments comprising a meltable synthetic polymer, and at least one matrix material embedded therein. The matrix material comprises a food-grade polymer, and the matrix material and the filaments form a belt of a certain length having opposing first and second ends. The first and second ends are melted together to form a continuous annular belt, and no filaments are exposed to the belt environment.

[0010] The tape may include a second layer of material extruded onto a first layer of material, and the filament may be embedded between the first and second layers. Both the first and second layers may comprise a thermoplastic elastomer or thermoplastic polyurethane. The first layer may define a smooth surface of the tape, and the second layer may define a surface with multiple ridges or teeth. The filament may be continuous along the annular shape of the tape. Each filament may comprise a monofilament or multiple filament strands. The filament may be antibacterial.

[0011] Another aspect of the invention relates to a method for manufacturing a continuous, annular, reinforced, food-grade tape. The method includes providing a plurality of parallel-arranged, meltable synthetic filaments; extruding a layer material to form a tape in which the filaments are embedded, the tape having opposing free ends with the filaments exposed at the free ends; arranging the free ends adjacent to each other; and melting the filaments and the layer material at the free ends to join the free ends together to form a continuous, annular, reinforced, food-grade tape. The filaments and the layer material may comprise a food-grade polymer material. Extruding the layer material may include extruding a first layer material onto the filaments and extruding a second layer material onto the layer material.

[0012] The foregoing has broadly outlined the features and technical advantages of the invention to facilitate a better understanding of the subsequent detailed description. Further features and advantages of the invention will be described below, forming the subject matter of the claims. Those skilled in the art will understand that the disclosed concepts and specific embodiments can readily serve as a basis for modifying or designing other structures that perform the same purpose as the invention. Those skilled in the art will also recognize that such equivalent structures do not depart from the scope of the invention as set forth in the appended claims. The characteristics believed to be new features of the invention, relating to both its organization and operation, as well as other objectives and advantages, will be better understood from the following description when considered in conjunction with the accompanying drawings. However, it should be clearly understood that each drawing is for illustrative purposes only and is not intended to limit the scope of the invention. Attached Figure Description

[0013] The accompanying drawings (which are incorporated in and form part of the specification, wherein similar reference numerals denote similar parts) illustrate embodiments of the invention and, together with the specification, serve to explain the principles of the invention. In the drawings:

[0014] Figure 1 This is a perspective view of an exemplary reinforcing strip according to the present invention;

[0015] Figure 2 yes Figure 1 The side view of the strip shown;

[0016] Figure 3 yes Figure 1 The end view of the strip shown;

[0017] Figure 4 This is a perspective view of an exemplary reinforcing strip according to the present invention;

[0018] Figure 5 yes Figure 4 The side view of the strip shown;

[0019] Figure 6 yes Figure 4 The end view of the strip shown;

[0020] Figure 7 This is a perspective view of an exemplary reinforcing strip according to the present invention.

[0021] Figure 8 yes Figure 7 The end view of the strip shown;

[0022] Figures 9A-9C This is an end view of an exemplary filament according to the present invention;

[0023] Figures 10A-10B It is a perspective view showing the steps of forming the cyclic belt according to the invention;

[0024] Figure 11 This is a diagram of a manufacturing system according to one embodiment of the present invention;

[0025] Figure 12 Through Figure 11 The system produces a partially fragmented perspective view;

[0026] Figure 13 This is an illustration of a part of a belt manufacturing system according to another embodiment of the present invention;

[0027] Figure 14 This is an illustration of a part of a belt manufacturing system according to another embodiment of the present invention;

[0028] Figure 15 This is an illustration of a part of a belt manufacturing system according to another embodiment of the present invention;

[0029] Figure 15A yes Figure 15 The system shows a perspective view of the cut section of the belt;

[0030] Figure 16 This is a flowchart of one embodiment of the method according to the present invention; and

[0031] Figure 17 This is a flowchart of another embodiment of the method according to the present invention. Detailed Implementation

[0032] This invention provides a method and apparatus for manufacturing an open belt made of an elastomeric matrix in which reinforcing elements (e.g., filaments) are embedded longitudinally. The invention also relates to such reinforced belts, whether provided as recirculating belts or continuous annular belts. Such belts can be toothed belts, flat belts, multi-V-ribbed belts, conveyor belts, and similar products. Particularly useful are toothed belts, which require precise control of the tooth spacing or "pitch". The elastomeric matrix can be thermoplastic polyurethane (TPU) or any other suitable thermoplastic elastomer (TPE). The method can also be used with castable or thermosetting resins or with vulcanized rubber matrices. The matrix can be a combination of materials, such as laminates or blends. The matrix material can contain any number of desired components, including, for example, antioxidants, anti-ozone agents, UV stabilizers, antimicrobial additives, processing aids, softeners, fillers, friction modifiers, foaming agents, etc.

[0033] Filaments (also known as fibers, multifilament cords, and tension elements) are typically composed of polymeric materials such as synthetic thermoplastic polymers. Filaments can include bundles of fibers, filaments, etc., and can be twisted or sheathed. Cords can be monofilaments or bundles of filaments (i.e., yarns) or twisted, braided, or sheathed yarns or bundles of yarns, and can be treated for adhesive or disposal purposes. The term cable is often used interchangeably with the term cord. In this document, filament will be used to refer to all types of multifilament elements, tension elements, cords, or tension cords.

[0034] The filaments disclosed herein (e.g., monofilaments and multifilament strands) can be made from thermoplastic synthetic polymers and can be extruded or spun into single or multiple strands. The filaments are preferably antibacterial and, more preferably, hydrophobic, depending on the material properties. When the belt ends are terminal, the exposed portion of such filaments is considered problematic in the food-grade industry. More importantly, when the exposed belt ends are heated before they are fused together to create a recirculating belt, the thermoplastic filaments melt and retract into the belt matrix material, thus eliminating any chance of exposure or ejection during the end-welding process. This retraction is believed to be a result of the relaxation of the high orientation of the synthetic polymer molecules frozen during fiber formation.

[0035] Regardless of the type of synthetic polymer reinforcement element used, the field installation, which currently requires proper execution by skilled technicians, can be performed by someone who is trained but not yet highly proficient in this task. Similarly, if this rigid element detaches due to negligence, there will be no need to address the need for a strip with holes arranged along the width of the discharge or intake application. In these cases, a heat source will be applied to the area, and the thermoplastic synthetic polymer filament will melt back into the strip.

[0036] Figure 1-3 An exemplary reinforced food-grade tape 100 is shown. Tape 100 includes a plurality of filaments 112 embedded in a first layer 114 (also referred to as web 114 or web material 114). A plurality of teeth 116 are formed along one surface of the tape, and ridge regions 118 are provided between adjacent teeth 116. Tape 100 includes first and second side surfaces 120, 122, first and second edges 124, 126, and first and second ends 128, 130. The first layer 114 of tape 100 has a thickness T1 and a total thickness T2, as shown. Figure 2 As shown. The pitch distance PLD can be defined as the distance from the centerline of the filament 112 to the first side surface 120, as follows. Figure 12 As shown. The distance between the filament 112 and the second edge 126 is S1 for the first filament, S2 for the second filament, and so on for each filament 112. The distance S... F Defined between each adjacent filament.

[0037] The filament 112 can be configured as a single filament 12A with a monopile structure, such as a filament 112 having a profile 113 and a diameter D1, as shown below. Figure 9A As shown. Optionally, the filaments 112 can be combined into multi-filament cables 12B and 12C, as shown respectively. Figure 9B and 9C As shown. Figure 9B The paired filaments 112 shown may each have a diameter D2. Diameter D2 may be smaller than diameter D1 to allow the two filaments 112 to fit together. Figure 9A The same contour 113 as the diameter D1 shown.

[0038] Figure 9C Another example of a multifilament cord 12C is shown, which has three filaments 112, each with a diameter D3. Figure 9C The filament 112 shown can be adapted to equal to Figure 9A The same profile 113 with diameter D1 is shown. Other embodiments comprising four or more filaments 112 that together fit into profile 113 of the same size are feasible. Some embodiments may include 10 or more individual filaments 112, or hundreds or thousands of filaments, such as filaments with diameters as small as a few micrometers. The multi-filament cords disclosed herein can be combinations of filaments with different diameters and are suitable for different... Figure 9A The outline 113 of the single filament diameter D1 is shown.

[0039] The filaments 112 contained in the multifilament cords 12B and 12C can have different arrangements, such as twisted, braided, or arranged in parallel side-by-side. They possess the same... Figure 9A Multifilament yarns with the same profile 113 as the monofilament 12A shown can have greater flexibility than monofilament yarns of the same material. Multifilament yarns can have other advantages compared to monofilament yarns, although monofilament yarns at least have the advantage of a simple, single structure that is easier to manufacture and handle. Multifilament yarns can be twisted in many turns per inch or turns per meter (e.g., wrapped if multiple yarns are used), which optimizes the balance between tensile strength and flexibility and handlingability.

[0040] The filament 112 is shown in the figure as having a circular cross-sectional shape. Other cross-sectional shapes are possible, including, for example, rectangular or elliptical. Different cross-sectional shapes can be selected based on their inherent properties, such as flexibility, stiffness, etc.

[0041] The filament 112 may comprise polymeric materials such as nylon-based materials, acrylic fibers, modified polyacrylonitrile fibers, polyolefins (e.g., polyethylene, polypropylene, etc.), vinylon, or polyester. Other types of polymeric materials may be used, including, for example, copolymers (e.g., two or more types of nylon or olefins), fluorocarbons, and blends such as nylon / fluorocarbons. In at least some examples, the filament comprises a synthetic polymer. It is generally known that synthetic thermoplastic polymers are meltable. In some examples, a filament comprising such a synthetic thermoplastic polymer can be joined to another such filament by heating the two filaments. It is also preferred that the material in the filament retracts upon heating, as well as melts and flows together. It is also advantageous if melting, followed by cooling or crimping of the filament material, creates a connection or bond to secure two filaments (or the ends of a single filament) together, or to create a connection or bond between the filament and the web material 114.

[0042] Typically, filament 112 comprises a material with a melting temperature equal to or less than that of the material used to produce the body of belt 100 (i.e., the first layer 114). Filaments 112 having such a melting point will effectively melt into the belt, where the belt ends are joined together using a heat source as part of forming a continuous annular belt. When supplied at or below the melting point of the belt's main material, the melting point of filament 112 inherently allows it to always be embedded within the rest of the belt so as not to be exposed to environmental conditions (which would otherwise make filament 112 a host for bacteria) or other conditions (which would affect the belt's ability to meet food-grade standards).

[0043] The first layer 114 (which may also be referred to as the web material 114) may comprise a polymeric material such as thermoplastic polyurethane (TPU) or other suitable thermoplastic elastomer (TPE). A preferred filament material having 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 comparable to aramid fibers. Exemplary UHMWPE fibers and yarns for use as filaments include those sold by Honeywell under the trademark Spectra and by DSM under the trademark Dyneema.

[0044] It is worth noting that the filaments or cords can be twisted or untwisted, depending on the application requirements. The filaments can be used directly (untreated) or can be coated or treated, for example, to improve adhesion, disposability, etc.

[0045] Although the accompanying drawings show a single layer of material for the web material 114, multiple layers (e.g., first and second layers) can be used. In one example, the multiple layers are formed separately and combined together, and / or one layer can be formed on top of another to form a looped tape in which filaments 112 are embedded. The filaments 112 can be embedded in any layer, or can be embedded between two or more layers. Various manufacturing methods and equipment can be used to produce the tape 100 in which filaments 112 are embedded. The method chosen is not critical to the tape formed, as long as it does not result in the exposure of the threads at the edges or on the surface when intended for food-grade applications. Figure 11-15 (described in detail below) are examples of such systems, devices, and methods that can be used in manufacturing Figure 1-3 The band shown is 100 or any other band disclosed herein.

[0046] The teeth 116 are shown arranged at intervals along the length of the band 100. The teeth 116 can have any desired profile shape (e.g., Figure 2 (The shape shown in the side view). Teeth 116 can be spaced any desired distance S. T And there is a groove ridge region 118 therebetween. The teeth 116 are shown as having a relatively linear straight-line structure along their length. The teeth 116 may extend between edges 124, 126 (i.e., edge-to-edge arrangement). Alternatively, the teeth 116 may extend only along a portion of the width W1 between edges 124, 126, as... Figure 4-6 As shown. Other implementations may not have any tooth 116, for example, see the following reference. Figure 7 and 8 The aforementioned band 300.

[0047] Thickness T1 is typically about 0.1 inches to about 0.5 inches, more specifically about 0.1 inches to about 0.2 inches. Thickness T2 is typically about 0.2 inches to about 1.0 inch, more specifically about 0.3 inches to about 0.5 inches. Generally, thickness T1 is greater than the maximum diameter D1 of filament 112, such as... Figure 9A As shown, and / or the outline 113 of the multi-length filaments 12B, 12C, as Figure 9B and 9C As shown. A thickness T1 greater than the diameter D1 and / or profile 113 is provided so that the filament 112 can be fully embedded into the web 114. In at least some arrangements, the diameter D1 and / or profile 113 is about 0.01 inches to about 0.1 inches, more specifically about 0.02 inches to about 0.05 inches.

[0048] Width W1 is typically between approximately 2 inches and 48 inches, and can be any size in between, depending on various factors and the standard for 100. Other arrangements may include width W1 greater than 48 inches, such as between approximately 48 inches and 84 inches. In at least some examples, the spacing S of the filament 112 F It's approximately 0.2 inches to 2 inches, more specifically approximately 0.3 inches to 1.0 inch. Distance S F The distance can be equal across all filaments 112. In some embodiments, the distance S F It is variable; for example, it may move closer together when adjacent to edges 124 and 126, and expand along the width W1 towards the center over time. Distance S F It can be any desired size, depending on the application and other performance requirements. Spacing S F It can vary considerably, depending on, for example, the thickness T1, the material used for the strip 100, the number of teeth 116 and their spacing, and the type of material used for the filament 112 and the first layer 114.

[0049] The distance S1 from the edge of the 100-stripe band to the first filament 112 is typically about 0.25 inches to about 2 inches, more specifically about 0.4 inches to about 0.6 inches. The distance S2 is equal to S1 plus the filament spacing S. F The distance to each other filament 112 is equal to S1 plus the filament spacing S. F .

[0050] Figure 4-6 Another exemplary food-grade belt 200 is shown, comprising filaments 212 formed in a web layer, a plurality of teeth 216 (having grooved ridge regions 218 located therebetween), first and second side surfaces 220, 222, first and second edges 224, 226, and first and second ends 228, 230. Belt 200 may include many features and properties identical or similar to those of belt 100 described above. Some differences between belt 200 and belt 100 include, for example, width, number, size, and spacing of teeth 216, and number, size, and spacing of filaments 212 (i.e., S). F S1-S x ).

[0051] Figure 7 and 8 Another exemplary food-grade tape 300 is shown, comprising filaments 312 embedded in a web, first and second side surfaces 320, 322, first and second edges 324, 326, and first and second ends 328, 330. Tape 300 includes a web thickness T1, a width W3, and a filament pitch S. F S1-S2. Belt 300 has no teeth 116 on either the first or second side surface 320, 322. Figure 1-8The exemplary belts 100, 200, and 300 shown are merely examples of various belt structures and designs that, when used in combination with material layer 114 (or a similar layer for belts 200 and 300), benefit from the use of one or more filaments 112, 212, and 312, maintaining the food-grade grading of the belt, particularly when the free ends of the belt are joined together to form a continuous loop belt.

[0052] Figure 10A and 10B An example of a loop belt having ends 128, 130 fused together to form a continuous or circular loop is shown. Ends 128, 130 are arranged adjacent to each other, and a fusion device 150 operates to fuse ends 128, 130 together. In at least one example, fusion involves melting the material of filament 112 and layer 114 to allow the material to flow together to produce a uniaxial structure. Figure 10B The loop after fusion is shown, in which the ends 128 and 130 are essentially eliminated due to the melting and retraction of the filament 112 material, the melting of the layer 114, and the subsequent solidification of those materials after they are fused together at the ends 128 and 130.

[0053] Filaments containing thermoplastic synthetic polymers can have different properties and produce results similar to non-melting conventional aromatic amide materials, such as... Different functions. Table I below includes test data for a section of the reinforcing strip of the present invention (which comprises two twisted thermoplastic synthetic polymer cables (UHMWPE)). The sample was tested using a toothed insert clamp according to a typical tensile testing protocol. The sample was held with three teeth at each end, and the gauge length was approximately 5 inches. A preload of 2.0 + / - 0.3 lbs was applied. As recorded in the results shown in Table I, the average maximum load was 388 lbs, and the average load at 2% elongation was 37 lbs.

[0054] Table I

[0055] Sample No. of this invention. Maximum load lbs. Load at 2% elongation (lbs). 1 398 37 2 382 37 3 386 36 average 388 37

[0056] The results shown in Table I are compared with those of a conventional band having two torsioned aramid fibers embedded therein (e.g., The results are highly favorable compared to similar test results for aramid fibers. Table II shows the test results for the standard tape, tested using the same tensile testing protocol with toothed insert clips. Three teeth were inserted into each end of the sample, and the gauge length was approximately 5 inches. A preload of 2.0 + / - 0.3 lbs was applied. The average maximum load was 298 lbs. The average load at 2% elongation was 27.3 lbs. Therefore, thermoplastic synthetic polymer cords with the same torsional structure as aramid fibers are able to withstand higher loads.

[0057] Table II

[0058] Compare with sample No. Maximum load (lbs.) At a load with 2% elongation (lbs.) 1 293 27.0 2 293 24.5 3 297 25.8 4 304 29.2 5 303 29.8 average 298 27.3

[0059] To test the welds, similar tensile tests were performed at three locations on three exemplary strips. The first location was the unwelded section of the strip. The second location was at the welded joint. The third location was at the finger weld, which has a triangular finger with a base width of approximately 30 mm and a length (or height) of approximately 70 mm. The test strip width associated with the data shown in Table III was approximately 3 inches, and the strip had 3-4 cords. The results shown in Table III represent the maximum load per cord based on the comparative food-grade strip with 1500 denier aramid cords, and the maximum load per cord for the two strips of the present invention, one with adhesive-coated UHMWPE cords and one with uncoated UHMWPE cords. The maximum load at the weld was slightly less than that of the unjointed portion of the comparative strip. Therefore, a conventional strip with welded joints or finger welds would likely fail at the weld joint, rather than somewhere along the strip length away from that joint. On the other hand, for the strips of the present invention, the maximum load at the weld was greater than that of the unjointed portion of the strip. Therefore, the band of the present invention spliced ​​with welded joints or finger welds may fail at a location far from the joint point, rather than at the joint point.

[0060] Table III

[0061]

[0062] One reason for attempting adhesive-coated UHMWPE yarns is the generally poor adhesion of UHMWPE to most matrix materials, including TPU. One unexpected result from the data shown in Tables I-III is that while the adhesion between UHMWPE fibers and polyurethane tape was presumably lower than that between aramid and polyurethane tape, the maximum load of the tape with UHMWPE was higher than that with aramid (see Tables I-III). An even more surprising result from the test data concerns the maximum load of welded joints and finger welds of UHMWPE compared to aramid, as shown in Table III. In the aramid samples, the maximum load at the welded joint was less than that of the unspliced ​​section of the tape, as is typically expected for any tape joint. However, for the UHMWPE welded joint, the maximum load was greater than that of the unspliced ​​section of the tape. One possible reason for this improvement in the maximum load of the welded joint when used can be assumed to be that the UHMWPE material shrinks back from the weld when approaching or exceeding its melting point (i.e., the melting point of the filament is equal to or less than the melting point of the polyurethane used for the tape in this case). Therefore, there is no discontinuity at the weld interface from the right side of the filament. In contrast, conventional aramid yarns do not melt or retract, thus potentially weakening the weld interface. Therefore, regardless of the reason, using meltable polymer yarns not only produces a better seal within the tape but also creates a stronger fusion or weld joint.

[0063] The following describes the process and method for manufacturing toothed belts using thermoplastic polyurethane and synthetic polymer filaments as tension elements, employing the methods and apparatus of this invention. It should be understood that this invention is not limited to these exemplary methods, materials, apparatus, or belt types.

[0064] Figure 11 and 12 A toothed belt 410 is shown, having three main components: a bottom layer 414 (also referred to as the first layer or first layer material or first web material), a plurality of filaments 412 (also referred to as multi-filament elements, tension cords, and tension elements), and a top layer 415 (also referred to as the second layer or second layer material or contour layer). One or both of the top and bottom main surfaces of the belt 410 may optionally comprise woven or nonwoven fabric, plastic film, or other surface treatments; however, in at least one embodiment, the belt 410 preferably comprises only food-grade material. The bottom layer 414 and the top layer 415 may be the same material or may be two different thermoplastic materials. The bottom layer 414 and / or the top layer 415 may be laminated from multiple layers of one or more materials or thermoplastic materials. Reinforcing material, whether filaments, multi-filament cords, etc., may be applied to the bottom layer 414, the top layer 415, or embedded between the bottom layer and the top layers 414, 415.

[0065] The bottom layer 414 may be made of continuously extruded TPE or TPU having flat surfaces on opposite sides, or may have teeth or other desired strip profiles on one side and flat surfaces on opposite sides. The top layer 415 may also be made of continuously extruded TPE or TPU having flat surfaces on opposite sides, or may have teeth or other desired strip profiles on one side and flat surfaces on opposite sides. The bottom layer 414 and the top layer 415 may be formed by known extrusion forming or molding methods, such as those disclosed in U.S. Patents 4,251,306 and 8,668,799, which are incorporated herein by reference in their entirety, and which use a molding wheel and a molding belt adjacent to approximately half the circumference of the molding wheel to form a rotating profile molding chamber into which profile material is extruded for continuous forming.

[0066] The final thicknesses of layers 414 and 415 are selected to allow the tension element to be embedded at a predetermined pitch distance (“PLD”). PLD is a measure of the strip thickness under the cable and is defined as the distance from the strip surface in the grooved ridge region to the cable centerline, such as... Figure 12 As shown. Figure 12 yes Figure 11 The diagram shows a partially fragmented bottom perspective view of band 410. The groove ridge region 418 is a thin segment of the band located between any two adjacent teeth 421 (see [reference]). Figure 12 ).

[0067] Filament 412 is typically made of continuous filaments. Filament 412 may comprise a single filament or may comprise a multi-filament cord in which individual filaments are twisted into cords. In some embodiments, filament 412 has an adhesive coating for bonding. Filament 412 is parallel to the edge of the strip. Two or more different filaments 412 may be placed side-by-side in the strip simultaneously. For example, one type of filament, or two or more filaments with the same or opposite twists (i.e., S and Z twists) may be used as filament 412. Preferably, the filament is completely embedded within the elastomeric matrix and is not exposed on either side. The adhesive coating may be applied to the filament prior to cord laying in a separate operation, or to the filament 412 or the underlayer 414 during filament laying in an integrated coating operation prior to the filament 412 contacting one or both of the elastomeric matrix materials of layers 414, 415.

[0068] The top layer 415 is typically made of a continuous TPE or TPU sheet of the same material as the bottom layer 414, or a different material or a different formulation. For example, the bottom layer 414 may be made of a relatively harder material for high gear tooth loads, while the top layer 415 may be made of a relatively softer material for higher flexibility, with different coefficients of friction and / or for noise reduction and / or cost reduction, or vice versa.

[0069] An exemplary manufacturing method according to the present invention includes the following steps, and refers to Figure 11 The device 400 shown. A bottom layer 414 with a desired flat surface on both sides, or a flat surface on one side and a textured (e.g., contoured) surface on the opposite side, is provided from a spool 409 with a desired length and width.

[0070] The bottom layer 414 is then fed around the meshing roller 404 onto the mandrel 402, as shown. Figure 11 As shown. The mandrel 402 and engagement roller 404 rotate at a predetermined speed to lay filaments in the wrapped portion of the mandrel 402 and roller 404 via a filament applicator. All desired number of filaments 412 are laid simultaneously, preferably arranged parallel to each other by length. The filament spacing can be uniform or in any other desired arrangement. In one example, sixteen filaments 412 are used. The filaments 412 are released from the spool 419, which can have any desired number of spools 408 (…). Figure 11 (Only four are shown), and the filament 412 is guided, for example, by guide rollers 422 and 423, and / or tensioned, for example, by tension rollers 425 and / or 426, and finally fed to the filament applicator roller 424.

[0071] The base layer 414 can be heated before it is wrapped around the roller 404 and before the filaments 412 are arranged to contact the base layer 414. Different heating devices can be used, depending on the material type of the filaments 412. For example, a hot air blower, a radiant heater, etc., can be used.

[0072] According to another embodiment, heated profile blades (not shown) can be positioned against the back side of the profile material to melt grooves in the profile material with precise depth, width, and temperature. The heated blades can have profiled edges that form grooves on the back side of the underlayer 414. Filaments 412 are then supplied from the filament spool 419 and fed to a roller 404, which positions the filaments 412 in the grooves to the desired depth to control the belt pitch. The groove width and depth can be approximately the same as the filament diameter. The heated blades preferably act as a plow, as they form grooves in the molten material. Before the groove material re-solidifies, a filament guide roller (not shown) can guide and press the filaments 412 into the grooves. The distance between the blades and the filament guide roller, the filament laying speed, and the temperature should be controlled to keep the TPE material molten or at least tacky until the filaments are embedded. The result is a reinforced underlayer 414 with fused filaments 412 thereon.

[0073] After the filament laying operation is completed, the material for the top layer 415 is applied to the bottom layer 414 with filaments 412 using an extruder 411. Figure 11The extruder 411 shown applies molten TPE or TPU material onto a base layer 414 and a filament 412, and presses the molten material onto a mandrel 402, the base layer 414, and the filament 412 to form a belt 410. The belt 410 can be collected on a spool 420.

[0074] The method of pressing the top layer 415 material onto the mandrel 402 results in the formation of a belt profile in the top layer 415. The belt profile refers to the belt surface structure suitable for engagement with pulleys or sprockets in the driving relationship of a belt drive system. In friction-driven belt drive systems, the belt profile may be flat, V-shaped, or multi-V-ribbed, while in synchronous or forced-drive systems, the belt profile may be a series of evenly spaced transverse teeth, angled teeth, or helical teeth. In other arrangements, the mandrel 402 forms a flat, smooth surface on the top layer 415.

[0075] The lamination speed and heat input process parameters should be adjusted so that only a thin, molten skin forms on both surfaces, without any material melting through and losing its shape. Uniform pressure along the entire length of the laminating rollers is also advantageous, and elastomeric rollers can be used to facilitate this, although steel rollers offer better heat transfer. Optimal heating and melting allow the top layer to fully bond to the bottom layer and the filaments, flowing around the filaments where they are not yet embedded, without disrupting the pitch and filament positioning.

[0076] Open strips can be cut to desired lengths and combined using known methods to form recirculating strips, and in the case of toothed strips, have a desired number of teeth. As non-limiting examples, the fusion of the ends can be thermal fusion by heat treatment or ultrasonic welding, direct adhesion, or film or tape, or clips, having welded joints or finger joints, or combinations thereof.

[0077] Any method by which the tape can be completely sealed to the target environment can be used for food use or other "clean tape" applications (referred to as "food grade" applications) that require cleaning, sterilization, etc.

[0078] Manufacturing the bottom layer 414 and top layer 415 separately offers numerous advantages over existing methods that form and assemble each on the same equipment. Separate manufacturing allows for the production of the bottom and top layer materials at optimal extrusion speeds, typically significantly faster than possible when filament layup and / or layer contracting is performed. Separate manufacturing also allows for significantly easier installation. Figure 11 The belt manufacturing system allows for a significantly simpler design and lower capital cost for the equipment. Specifically, it eliminates the need for complex extruders with crosshead dies for multiple filaments and conventional molding pressure belts and their associated drive systems. Setup time can be significantly reduced, and the use of filament materials can be improved.

[0079] Figure 13 and 14Other exemplary methods or systems 500 and 600 are shown respectively. Figure 13 In the first step shown, filaments 412 are laid onto a smooth mandrel 402', then coated with a matrix material from an extruder 411, which is then cooled under pressure band 452 to form a preform 477, which is a flat film with filaments suitably embedded at its surface. The filaments 412 can be a plurality of parallel filaments 412, as described for other embodiments. Figure 14 In the second step shown, a contour mandrel 402 replaces a smooth mandrel 402' to create the contoured belt 410. Of course, a smooth mandrel can be used again to create a flat belt. An extruder and pressure zone are now used to form the contoured layer, while a flat preform 477 is fed into the pressure zone. Thus, the flat preform containing drawn filaments is laminated to the contoured layer during its formation. The filaments 412 are preferably placed against the contoured layer, where they are just embedded, to seal them. The first step has been found to provide a flat film with very well controlled filament positioning because the filaments 412 are laid on the smooth mandrel. The formed belt 410 has very good filament control, and the PLD can be easily controlled by arranging the pressure zone. According to another variation, this two-step process can be performed using a suitably arranged laminating roll close to the mandrel or forming roll, instead of the pressure zone shown in the figures.

[0080] Alternatively, this or many other variations can be achieved using two or more passes of material, with equipment similar to that described herein. For example, the first pass can produce a blank, whether toothed or flat. The second pass forms and / or laminates a top layer on the blank. Another pass can weld, glue, or attach to profiled parts, such as toothed belts for driving belts on pulleys, or other objects, profiles, supports, or features that may ultimately be used for transporting goods or handling materials.

[0081] Figure 15 Another exemplary system and related method 700 for forming a reinforcing belt 410 is shown. The belt 410 has a base layer, or a base layer 414 formed on a plurality of filaments 412. The belt 410 is formed using a through-die method. The die may be connected to some type of extruder 411. System 700 may include rollers 402, 404, as in a calendering method for forming a reinforcing belt.

[0082] Filament 412 is typically made of continuous filament. Filament 412 may comprise a single filament or may comprise a multi-filament cord in which individual filaments are twisted into a cord. In some embodiments, filament 412 may have an adhesive coating for bonding. Filament 412 is released from spool holder 419, which may have any desired number of spools 408, and the filament is guided and / or tensioned by tension roller 425 before being fed into rollers 404 and 424.

[0083] During the formation of layer 414, filament 412 is applied and fused to layer 414 using a continuous process. Layer 414 is typically made from continuous TPE or TPU sheets. The matrix material flow used to produce layer 414 is supplied via extruder 411 between meshing rollers 404 and mandrel 402, such as... Figure 15 As shown. Figure 15A A cross-sectional view of the formed strip 410 is shown, having filaments 412 embedded in layer 414. The strip 410 can then be collected on spool 420. One or more rollers 402, 404 can be profiled to produce a desired profiled strip instead of the flat strip shown. Other systems may include crosshead dies instead of rollers 402, 404.

[0084] Figure 16 This is a flowchart illustrating the steps of an exemplary method 800 according to the present invention. Method 800 may relate to a method of manufacturing a reinforced food-grade belt. Method 800 includes providing a plurality of thermoplastic synthetic filaments in step 802. Step 804 includes providing a thermoplastic elastomer belt body material. In step 806, the method includes embedding the filaments into the belt body material. Step 808 includes shaping the body material into a desired belt profile.

[0085] Method 800 can be continuous, forming a long strip. Method 800 may include cutting the strip to a predetermined length and fusing the ends together to form a revolving strip. Multiple filaments may be melted during the fusing step. The multiple filaments may be arranged in parallel and extend along the length dimension of the strip. The multiple filaments may contain a meltable synthetic polymer. The melting point of the multiple filaments may be approximately equal to, equal to, or less than the melting point of the strip bulk material. The melting point of the filaments may be within 50°C, 40°C, 30°C, or 20°C of the melting point of the strip bulk material. Each of the multiple filaments may include a single filament or a multi-filament strand. The filaments may be introduced into the first layer of material using a die during the extrusion of the first layer material.

[0086] Figure 17 This is a flowchart illustrating the steps of an exemplary method 900 according to the present invention. Method 900 may relate to a method of manufacturing a continuous annular reinforced food-grade tape. Method 900 includes, in step 902, providing a plurality of parallel-aligned meltable synthetic filaments. Step 904 includes extruding a layer material to form a tape in which the filaments are embedded, the tape having opposing free ends, and the filaments being exposed at the free ends. Step 906 includes arranging the free ends adjacent to each other. Step 908 includes melting the filaments and layer material at the free ends to join the free ends together to form a continuous annular reinforced food-grade tape. The filaments and layer material may comprise a food-grade polymer material. Extruding the layer material may include extruding a first layer material onto the filaments and extruding a second layer material onto the layer material.

[0087] The systems and methods described herein can also be used to manufacture other forms of strips or strip articles, such as tracks used in track drive systems for different types of track-driven vehicles.

[0088] The enhanced strip and related manufacturing methods disclosed in this paper can provide one or more of the following improvements / advantages compared to conventional solutions:

[0089] • The ability to form a continuous, ring-shaped reinforced belt that meets food-grade standards by preventing any part of the reinforcing filaments from being exposed after the free ends of the belt are joined together to form a loop.

[0090] • Reinforcing elements are used, which can increase the strength of the strip at the weld joint, contrasting with the portion of the strip that is spaced apart from the joint.

[0091] • It makes it easier to create food-grade weld joints by not exposing the filaments.

[0092] While the invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made therein without departing from the scope of the invention as defined by the appended claims. Furthermore, the scope of this application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, compositions of matter, means, methods, and steps described in the specification. As will be readily understood by those skilled in the art from the disclosure of this invention, existing or later-developed processes, machines, manufactures, compositions of matter, means, methods, or steps (which perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein) can be used according to the invention. Therefore, the appended claims are intended to include such processes, machines, manufactures, compositions of matter, means, methods, or steps within their scope. The invention disclosed herein can be suitably practiced in the absence of any elements not explicitly disclosed herein.

Claims

1. A method for manufacturing reinforced food-grade belts, comprising: Offers a variety of thermoplastic synthetic filaments; Provide thermoplastic elastomer tape body material; The filament is embedded into the main material of the belt; and This allows the main material of the belt to form the desired belt profile. The melting point of the filament is equal to or less than the melting point of the main material of the belt, and is within 50°C of the melting point of the main material of the belt.

2. The method of claim 1, wherein the method is continuous, forming a strip of long length.

3. The method of claim 2, further comprising cutting the strip to a predetermined length and fusing the ends together to form a loop strip.

4. The method of claim 3, wherein the plurality of filaments are melted during the fusion step.

5. The method of claim 1, wherein the plurality of filaments are arranged in parallel and extend along the length of the strip.

6. The method of claim 1, wherein the plurality of filaments comprise a meltable synthetic polymer.

7. The method of claim 1, wherein each of the plurality of filaments comprises a single filament or a multi-filament cord.

8. The method according to claim 1, wherein during the extrusion of the first layer material, the filament is introduced into the first layer material using a die.

9. A continuous, annular, reinforced food-grade belt comprising: Multiple extruded filaments containing a meltable synthetic polymer; At least one matrix material containing a food-grade polymer is embedded in the filament. The matrix material and the filament form a strip of a certain length having opposing first and second ends. The first and second ends are melted together to form a continuous annular strip, and no filament is exposed to the strip environment. The melting point of the filament is equal to or less than the melting point of the matrix material and is within 50°C of the melting point of the matrix material.

10. The tape of claim 9, further comprising a second layer of material extruded onto the first layer of material, the filament being embedded between the first and second layers of material.

11. The tape of claim 10, wherein the first layer material and the second layer material comprise a thermoplastic elastomer or a thermoplastic polyurethane.

12. The strip of claim 10, wherein the first layer of material defines a smooth surface of the strip and the second layer of material defines a surface having a plurality of ridges.

13. The belt according to claim 9, wherein the filament is continuous along the annular shape of the belt.

14. The tape of claim 9, wherein each of the filaments comprises a single filament or a multifilament cord.

15. The belt according to claim 9, wherein the belt is a forced-drive belt.

16. A method for manufacturing a continuous annular reinforced food-grade belt, comprising: Provides multiple meltable synthetic filaments arranged in parallel; Extruded layer material is used to form a tape in which filaments are embedded, the tape having opposing free ends, and the filaments being exposed at the free ends; Arrange the free ends adjacent to each other; The filament and layer material are melted at their free ends to join them together, forming the continuous, annular, reinforced, food-grade tape. The melting point of the filament is equal to or less than the melting point of the layer material and is within 50°C of the melting point of the layer material.

17. The method of claim 16, wherein the layer material comprises a food-grade polymer material.

18. The method of claim 16, wherein the extruded layer material comprises: The first layer of material is extruded onto the filament; and The second layer of material is extruded onto the first layer.

19. The method of claim 16, wherein the extruded layer material comprises: The first layer is extruded, then the filament is placed on the first layer, and the second layer is extruded onto the filament.

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