Applicant hereby claims the priority benefits under the provisions of 35 U.S.C. §119, basing said claim of priority on PCT/EP20009/003344, claiming priority to EPC 080093586, filed May 21, 2008. In accordance with the provisions of 35 U.S.C. §119 and Rule 55(b), a certified copy of the above-listed EPC patent application will be filed before grant of a patent.
The present invention relates to belt connectors of the type having wire hooks to interconnect the opposite ends of a belt. Each wire hook has two shanks arranged on opposite sides of the belt, and furthermore has hook ends adjoining the shanks, wherein the hook ends are pressed into the carcass of the belt. Each wire hook also has a coupling loop connecting the two shanks. The belt connector furthermore has a flat cover element that extends on both sides of the belt to cover portions of the hook assembly. The cover element extends across the width of the belt, and has a carrier material and a coating applied to the side facing the belt, that is made of a thermoplastic or an adhesive, especially a hot melt adhesive or an elastic adhesive, for attaching the cover element to the belt.
The invention furthermore relates to a method for producing such a belt connection.
A connection of the type cited in the foregoing is known from WO 2007 025567 A1. The wire hooks are held in a strip-like carrier material made of a textile fabric. One side of the carrier material is coated with an adhesive or provided with a thermoplastic. When the connection is made, heat generated by press jaws causes the carrier material and belt to fuse together. The cover element covers portions of the wire hooks and the belt end in order to prevent the wire hooks, especially damaged wire hooks, from damaging or otherwise having a negative effect on goods being conveyed on the belt.
Belt connectors embodied as wire hooks and connected to one end of a belt using a cover element that extends across the width of the belt are furthermore known from EP 1 338 825 A1. The belt is for instance embodied as a plastic belt, especially a polyurethane belt. The cover element is embodied as a fabric belt or plastic molded part and is provided with a layer of adhesive, especially a layer of hot glue, or an elastic adhesive. The wire hooks are attached to the belt and the cover element is added preferably in one operation, wherein the cover element is glued to the shanks of the hooks and the belt, especially using heat.
A method for pressing wire hooks into flat fabric comprising plastic is known from DE 36 42 803 A1. The shanks of the wire hooks are heated prior to bending. During bending the plastic of the flat fabric is partially plasticized and the wire hooks are pressed together, such that in their final pressed state, the exterior dimension of the shanks is never greater than the thickness of the flat fabric.
DE-PS 732 524 describes belt connectors that are embodied as wire hooks and connected to one end of a belt. The shanks of the wire hooks are embedded in a rubber cover layer of the belt. The belt comprises a fabric core and the rubber coatings. Producing such a connection is very complex because vulcanization is required in order to apply the rubber cover layers.
When joining belts, such as screen conveyor belts, press conveyor belts, filter conveyor belts, transport conveyor belts, and flat conveyor belts, it is known from DE 100 29 571 A1 to spray the end of the belt in a tool with a free-flowing material that consolidates when cooled. The material creates a permanent connection to the belt in the longitudinal direction of the belt at the given tensile forces. Each half of the belt joint is provided with alternating projections and recesses. The projections are provided with aligned channels through which a cotter pin can be passed. Substances used for the free-flowing materials are metals and plastics, such as thermoplastics, thermosetting plastics, and condensation resins, especially polyurethanes. Woven, knitted, laid, homogenous, and coated belts made of textiles, metal substances, plastics, and metal fabrics are also used commercially. Joining such belts in the manners described above is very complex, and in particular, is very time-consuming.
Devices such as that in accordance with EP 0 682 645 B1 are used for dewatering suspensions. These devices have belts that are made of a porous filtering web. The spaces in the filtering web can be used to dewater the suspension. Such a suspension is used for instance with sludge. Two conveyor belts are arranged relatively close to one another. They press the suspension between them during conveying so that the spaces in the belts are dewatered.
Such devices are also used for instance for extracting fruit and vegetable juices, dewatering draff, and producing algae and herbal extracts. The fluid is drained off by pressing the products between conveyor belts that are made of a filtering web.
With such devices, it is necessary to remove the filter cake after the dewatering has taken place. The filter cake is removed using wipers that contact the rotating belt. Thus, the wipers also contact those areas of the belt in which belt connectors and their covers are located. These areas are then subjected to increased wear, especially when material that has abrasive parts is being conveyed, for instance sand particles.
One object of the present invention is to ensure durable and wear-resistant attachment of the cover element to the belt in a connection of the type cited in the foregoing. Another object of the present invention is to provide a method that ensures, in a particularly simply manner, the connection of the wire hooks to the belt and the durable and wear-resistant attachment of the cover element to the belt. It should be possible to produce the connection in a short period of time.
The invention is particularly adapted for belts embodied as filtering belts, wherein the coating applied thereto passes at least partially through spaces in the filtering belt.
The invention takes advantage of the fact that the belt is embodied as a porous filtering belt, wherein the belt is embodied for the purpose of performing filtering processes by means of the belt. The belt is for instance provided as a fabric belt with warp and weft threads that form spaces or pores between them. Liquid portions of the product to be filtered can pass through the belt through these spaces. It is not necessary for this liquid to pass through in the area of the belt ends, where the wire hooks are to be connected to the belt. The cover is attached there. A coating applied to the carrier material deforms during heating, and when the cover element is applied such that the spaces in the filtering belt are at least partially filled by the coating material. Thus, there is a positive-fit or interlock connection between the applied coating and the filtering fabric, in that the deformed applied coating extends into the spaces or pores in the filtering belt in at least some areas thereof, and thus extends essentially vertical to the surface of the filtering belt for the product to be filtered. The cover is thus extremely well-suited for absorbing forces that act in the direction of tension for the belt. This is because the positive fit between the applied coating and the filtering belt transmits the force in this direction. This arrangement makes a significant contribution to creating the durable and wear-resistant attachment of the cover element to the belt.
The applied coating preferably passes into or through the spaces or pores on both sides of the filtering belt. Thus, it covers the wire hooks in the area of both shanks. It is particularly advantageous when the applied coating is fused into the belt spaces from both above and below the belt, that is, from both sides or faces of the belt. In this case, not only is the applied coating deformed on each side of the belt, it also projects into the spaces or pores of the filtering belt. In addition, those areas of the applied coating that project into each space of the filtering belt define fingers, such that when the connection is made, the heat and pressing force that is used on both sides of the filtering belt fuse together or unite the ends of these fingers of the applied coating that project into each of the belt spaces. Thus, the areas of the applied coating are positively and mechanically joined or interlocked, and this connection is thereby very secure after the areas cool. The areas of the cover element that are arranged on both sides of the belt are thus securely connected to one another via the applied coatings via the spaces or pores in the belt.
The belt preferably comprises plastic, metal, or a non-woven material, specifically a felt, especially a felt made of plastic. When creating the belt from plastic, it is considered particularly advantageous when it comprises polyester or nylon. Particularly good filtering properties with a very simple composition of the belt result when the belt is a filtering fabric. The latter comprises especially monofilament fibers and/or spun fibers.
The belt, especially the fabric, preferably has a melting point that is in particular significantly higher than the melting point of the applied coating. The melting point of the applied coating is for instance 180° C., while the melting point of the fabric is 220° C. This means that when the applied coating is molten, especially when it is in a paste-like state, the fabric has not reached its melting point. This is particularly important because the belt should be prevented from reaching its melting temperature, which would cause it to deform and remain in this deformed condition after cooling. Deformation is disadvantageous from the perspective of guiding the belt over deflection rollers for the belt. Deformation of the belt furthermore has a negative effect on its tensile properties.
The belt is made in particular from a filtering fabric of monofilament fibers and/or spun fibers. Monofilament fibers are used in one direction, for instance, and multifilament fibers are used in the other direction.
From the perspective of enhancing the resistance of the connection to wear, it is considered particularly advantageous when an additional cover element is connected to the cover element on its side facing away from the belt. This additional cover element reinforces the thickness of the cover stratum that is formed by the two cover elements. As a rule, the cover elements comprise the same material. Both have the carrier material and the coating applied thereto. The additional cover element is attached by means of the applied coating of the additional cover element to the carrier material of the cover element that is attached directly to the belt.
The additional cover preferably extends in the longitudinal direction of the belt beyond the end areas of the other cover, and thus beyond the cover that covers the belt directly. Because of this configuration, when the belt rotates there is a leading incline of the additional cover element, starting from the belt. This incline means the thickness of the double cover elements does not create or constitute a step.
With regard to the cover and/or additional cover, it is considered particularly advantageous when their carrier material constitutes a fabric. While in particular the fabric of the belt has a wide mesh for attaining the filtering property, the fabric for the cover and/or the additional cover is in particular fine-meshed. However, this fabric should also have spaces, even if they are small. When the two cover elements are connected, the applied coating for the additional cover element can pass through the spaces in the carrier element of the cover element connected to the belt so that it can create a positive-fit connection to the carrier material for the cover connected to the belt. It may even cause the two applied coatings for the cover elements to connect physically.
In order to prevent plasticization of the carrier material for the cover and/or the additional cover during the plasticization of the two applied coatings, which are especially thermoplastic, the melting point of the carrier materials should be higher than the melting point of the applied coating. The carrier material for the cover and/or the additional cover in particular comprises polyester or nylon. The carrier material for the cover and/or the additional cover preferably constitutes a fabric made of monofilament fibers and/or spun fibers.
The cover element can completely or even only partially cover the shanks of the wire hooks. The cover element and/or the hook arrangement in particular extend across the entire width of the belt. The belt may be quite wide; for instance, it may be up to 3 meters wide.
One object of the present invention is furthermore attained using a method for connecting belt connectors embodied as wire hooks to one end of a belt, wherein each wire hook has shanks that are arranged on opposite sides of the belt. Each wire hook also has hook ends that adjoin the shanks and that can be pressed into the belt, wherein each wire hook has a coupling sleeve that connects the two shanks. The method also connects belt connectors to a flat cover element that is for the hook arrangement, that is arranged on both sides of the belt, and extends across the width of the belt. The cover element has a carrier material and a coating that is applied thereto on its side facing the belt, and is made of a thermoplastic or an adhesive, especially a hot melt adhesive or an elastic adhesive, for attaching the cover element to the belt. The method has the following steps:
In particular, the method produces the connection specified according to the aforesaid solution. This connection presses the wire hooks held in the cover element into the filtering belt. The applied coating is heated and plasticized material from the coating is pressed into the spaces of the filtering belt.
In particular it is provided that after the wire hooks with the cover are pressed in, they are heated in a separate workstation under relatively low pressure. Then, immediately thereafter, in another workstation, the plasticized applied material of the coating is pressed into the spaces of the filtering belt under relatively high pressure and then cooled. The plasticization of the applied material of the cover can be attained using different methods, such as for instance friction, irradiation, ultrasound, heating plates, hot air, or the like.
The wire hooks are preferably clenched or pressed closed at a pressure of 15.0 to 35.0 N/mm2 and/or the cover element is heated at a pressure of 0.2 to 0.6 N/mm2 and/or the plasticized material of the coating is pressed into the spaces at a pressure of 5.0 to 25.0 N/mm2.
The invention thus proposes a connection of belt connectors embodied as wire hooks to one end of a filtering belt using a cover element and proposes a method for producing the connection, wherein in particular:
The applied material is in particular a thermoplastic, and the filtering belt is a fabric belt made of plastic.
Additional features of the invention are depicted in the subordinate claims, the description of the figures, and the figures themselves. It is hereby noted that all individual features and all combinations of individual features are essential to the invention.
The invention is depicted using a plurality of exemplary embodiments without being limited thereto.
For purposes of description herein, the terms “upper”, “lower”, “right”, “left”, “rear”, “front”, “vertical”, “horizontal” and derivatives thereof shall relate to the invention as oriented in
For the first embodiment,
The lower shanks 2 and 3 of the hook assembly 7 (relative to the orientation according to
The cover element 10 is arranged symmetrical with respect to the axis 8. The cover element 10 comprises a carrier material 11 and a thermoplastic coating 12 that covers an interior face of carrier material 11. The thermoplastic coating 12 is thus employed to connect the cover element 10 to one end of a conveyor belt in a manner to be described in greater detail. The carrier material 11 may be constructed from a fabric that is made of monofilament fibers having warp and weft threads. This type of carrier material 11 comprises for instance polyester or nylon threads. The thermoplastic coating 12 is for instance a coating that comprises polyurethane.
The belt connector illustrated in
The carrier material 11 for each cover element 10 and 13 is preferably woven, having a fine mesh, so that only small spaces or pores exist between the warp threads 14 and the weft threads 15 of the carrier material 11.
In the inventive method, the thermoplastic coatings 12 are heated only just to their melting point, which is for instance 180° C. This melting point is clearly less than the melting point for the porous fabric of the conveyor belt 16, which is for instance 220° C. This ensures that the conveyor belt 16 does not deform when the thermoplastic coatings 12 plasticize. The connection between thermoplastic coatings 12 and the conveyor belt 16 is the result of the positive interlocking of the melted material of the carrier layers 11 in the spaces 19 of conveyor belt 16, and as plasticization progresses, it is further enhanced by the interconnection of the two streams of thermoplastic material that flow into both sides of the conveyor belt pores 19 and join together. The hot thermoplastic material penetrates into the same conveyor belt spaces 19 from the opposite ends of the spaces 19 and unite.
Significantly higher resistance to the belt connection tearing results from this special positive-fit or interlocking connection, especially between the carrier material 11 and the conveyor belt 16. This is not to mention the connection's long service life and great resistance to wear.
Regardless of the embodiments used to clarify the description of the figures, in which embodiments thermoplastic coatings are provided, an adhesive, in particular a hot-melt adhesive or an elastic adhesive, may be used instead of a thermoplastic.
In the foregoing description, it will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.
Number | Date | Country | Kind |
---|---|---|---|
08009358 | May 2008 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP2009/003344 | 5/12/2009 | WO | 00 | 1/11/2011 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2009/141071 | 11/26/2009 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3031359 | Blank et al. | Apr 1962 | A |
5017788 | Humphrey et al. | May 1991 | A |
5405477 | Arnold | Apr 1995 | A |
6627045 | Raczkowski et al. | Sep 2003 | B2 |
6896124 | Herold | May 2005 | B2 |
20010054592 | Day | Dec 2001 | A1 |
20030150698 | Herold | Aug 2003 | A1 |
20050229995 | Ito et al. | Oct 2005 | A1 |
20090057105 | Suelzle | Mar 2009 | A1 |
Number | Date | Country |
---|---|---|
732524 | Mar 1943 | DE |
1245908 | Aug 1967 | DE |
3642803 | Jun 1988 | DE |
19526458 | Jan 1997 | DE |
10029571 | Jan 2002 | DE |
0682645 | Nov 1995 | EP |
1338825 | Aug 2003 | EP |
2101080 | Sep 2009 | EP |
2007025567 | Mar 2007 | WO |
WO 2007025567 | Mar 2007 | WO |
Entry |
---|
Non-English International Search Report for PCT/EP2009/003344 (4 pages). |
Non-English PCT Written Opinion for PCT/EP2009/003344 (7 pages). |
Number | Date | Country | |
---|---|---|---|
20110100896 A1 | May 2011 | US |