Abstract:
A composite sheet structure is presented, and includes a core layer and two surface layers. Each surface layer has a plurality of metallic sheets. The metallic sheets bond with one another. The core layer and the surface layers bond with each other, and the core layer is sandwiched between the two surface layers. In comparison to conventional single type/solid piece of building material, the present invention results in a dramatic cost reduction in various building industry. With the up-to-date technology, the strength of metallic composite sheet remains within structural grade parameter and meets related specifications. Manufacturers are benefited from the cheaper metallic sheet in the composition while enjoying the same quality look of the outer layer.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application claiming only subject matter disclosed in prior application of U.S. application Ser. No. 12/153,740 filed on May 23, 2008 directed to 35 USC 120. The contents of all of which are incorporated herein their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a kind of composite sheet structure that can be used as building and industrial material. 
     2. Description of the Related Art 
     Please refer to  FIG. 1 , representing a typical structure plan of traditional composite sheet, wherein the traditional composite sheet represents one kind of exterior cladding material in the building industry. The process of producing a traditional composite sheet includes the steps of (a) putting some plastic materials into an extruder which extrudes and heats the plastic materials (i.e. resin) until the plastic materials are melted; (b) the melted plastic materials are transported to a mold to become a flat core layer  1   a  of the composite sheet; (c) provide two metallic surfaces layers  2   a  to bond with the core layer  1   a.    
     As shown in  FIG. 1 , the structure of a traditional composite sheet includes the core layer  1   a , and the two surface layers  2   a . The core layer  1   a  is sandwiched between the two surface layers  2   a.    
     Because quantities of easily accessible natural resources (specifically metals) on Earth are decreasing, the cost of the composite sheet made of exotic metals will be more and more expensive. However, if we simply decrease the quantities of the more expensive metals for the metallic surface layers  2   a  and attempt to reduce the cost of the composite sheet in this simple fashion, the strength of the composite sheet would suffer and may not be enough to reach industry safety regulations. 
     SUMMARY OF THE INVENTION 
     One particular aspect of the present invention is to provide a composite sheet structure, the strength of the composite sheet not only can satisfy the industry safety regulation, but also the weight of the composite sheet can be reduced compare to traditional composite sheet, and the cost of producing the composite sheet of the present invention can be effective reduced. 
     The composite sheet structure includes a core layer and two surface layers, wherein each surface layer has a plurality of metallic sheets, the metallic sheets bond with one another, the core layer and the surface layers bond with each other, and the core layer is sandwiched between the two surface layers. 
     This invention has several advantages: by carefully choosing the composite materials used to produce the surface layers, and coupled with the present invention, thereby reducing the quantity requirement for the more expensive metal on the surface layers and the core layer of the composite sheet, and due to the bonding method of the present invention the strength of the composite sheet will still satisfy industry safety regulation and the cost of producing the composite sheet can be effectively reduced. The weight of the composite sheet can be light (due to the fact that the more expensive metals are generally heavier), so that it is very convenient for fabricator and installer to assemble many of the composite sheets with each other. 
     For further understanding of the invention, reference is made to the following detailed description illustrating the embodiments and examples of the invention. The description is only for illustrating the invention and is not intended to be considered limiting of the scope of the claim. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings included herein enable a further understanding of the invention. Brief introduction of the drawings are as follows: 
         FIG. 1  is a plan of the structure of the traditional composite sheet. 
         FIG. 2  is a process for producing the composite sheet structure of the first embodiment of the present invention. 
         FIG. 3  is a schematic view of the manufacturing equipments with respect to  FIG. 2 . 
         FIG. 4  is a process for producing the composite sheet structure of the second embodiment of the present invention. 
         FIG. 5  is a schematic view of the manufacturing equipments with respect to  FIG. 4 . 
         FIG. 6  is a process for producing the composite sheet structure of the third embodiment of the present invention. 
         FIG. 7  is a process for producing the composite sheet structure of the forth embodiment of the present invention. 
         FIG. 8  is a process for producing the product of the composite sheet structure of the first embodiment of the present invention. 
         FIG. 9  is a schematic view of the manufacturing equipments with respect to  FIG. 8 . 
         FIG. 10  is a process for producing the product of the composite sheet structure of the second embodiment of the present invention. 
         FIG. 11  is a process for producing the product of the composite sheet structure of the third embodiment of the present invention. 
         FIG. 12  is a process for producing the product of the composite sheet structure of the forth embodiment of the present invention. 
         FIG. 13  is a process for producing the product of the composite sheet structure of the fifth embodiment of the present invention. 
         FIG. 14  is a plan of the product of the composite sheet structure of the first embodiment of the present invention. 
         FIG. 15  is a plan of the composite sheet structure of the second embodiment of the present invention. 
         FIG. 16  is a plan of the composite sheet structure of the third embodiment of the present invention. 
         FIG. 17  is a perspective view of the composite sheet structure of the forth embodiment of the present invention. 
         FIG. 18  is a perspective view of the composite sheet structure of the fifth embodiment of the present invention. 
         FIG. 19  is a perspective view of the composite sheet structure of the sixth embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIG. 2  and  FIG. 3 . A first embodiment of a process for producing a composite sheet is presented, and the process includes the steps of: 
     (a) provide a plurality of metallic sheets  1  (top, middle, and bottom metallic sheets  1 ), wherein the metallic sheets  1  are coiled around a coiling roller group  21 , and the metallic sheet  1  are made of aluminum, copper, steel, zinc, or titanium. 
     (b) Uncoil the metallic sheets  1  coiled around the coiling roller group  21  (uncoiling can be done by motor (not shown) or any other power generating equipment, which is beyond the scope of the present invention), then as the metallic sheets are uncoiling, the top and bottom metallic sheets  1  are passed through a stretching roller group  22 , and the stretching roller group  22  extends, stretches, and flattens the top and bottom metallic sheets  1 . 
     (c) the middle metallic sheets  1  have top and bottom surfaces (here on now referred as contact surfaces) respectively, place a plurality of adhesive on the contact surfaces of the middle metallic sheets  1 , heat the adhesive films via a set of heating rollers  23  to form a plurality of bonding layers on the contact surfaces respectively. 
     (d) the metallic sheets  1  are passed through a forming roller group  24 ; the forming roller group  24  includes a pair of first forming rollers  241 , a pair of second forming rollers  242 , and a pair of third forming rollers  243 . The metallic sheets  1  are pressed by the first forming rollers  241 , the second forming rollers  242 , and the third forming rollers  243  in sequence. The forming roller group  24  presses the metallic sheets  1  against the bonding layers in sequence, the metallic sheets  1  bond with each other via the bonding layers, and a composite sheet  3  having a plurality of metallic layers is finished. Though the metallic sheets  1  are not made of the more expensive metals, the strength of the composite sheet  3 , due to the bonding process, would still satisfy industry safety regulation. In one embodiment, the top, middle, and bottom metallic sheets  1  in  FIG. 3  are made of different materials. Generally, the metallic sheets  1  that would eventually be the “presenting surface” or “top surface,” will be made of the more expensive metal, whereas the middle and bottom metallic sheets  1  would be made of lighter and cheaper metal. 
     As shown in  FIG. 4  and  FIG. 5 , represent the second embodiment of the present invention. Similar to  FIGS. 2 and 3 , except that a plurality of adhesives are coated on the contact surfaces of the middle metallic sheets  1  by two adhesive applying units  25  (only  1  shown) with different vertical positions, and the adhesives are bonding layers of the composite sheet  3 . 
     The kinds of the adhesives used are not restricted, as long as the adhesives can bond the metallic sheets  1  with one another securely. The temperature of the set of heating rollers  23  depends on the adhesive applying units  25 , and only needs to be high enough for proper adhesive bonding. 
       FIG. 6  is a process for producing the composite sheet structure of the third embodiment of the present invention. The bonding layers are formed by the set of heating rollers  23 . The radius of each third forming roller  243  is longer than the radius of each second forming roller  242 , and the radius of each second forming roller  242  is longer than each radius of the first forming roller  241 . The metallic sheets  1  are pressed by the first forming rollers  241 , the second forming rollers  242 , and the third forming rollers  243  in sequence to contact with the bonding layers respectively, and the metallic sheets  1  bond with each other via the bonding layers. 
       FIG. 7  is representing a process for producing the composite sheet structure of the fourth embodiment of the present invention. The bonding layers are formed by the two adhesive applying units  25 . The radius of each third forming roller  243  is longer than radius of each second forming roller  242 , and the radius of each second forming roller  242  is longer than the radius of each first forming roller  241 . The metallic sheets  1  are pressed by the first fanning rollers  241 , the second forming rollers  242 , and the third forming rollers  243  in sequence to contact with the bonding layers, and the metallic sheets  1  bond with each other via the bonding layers. Furthermore, we can bond the metallic sheets  1  with each other by a metallic bonding process via heat conduction. 
     As shown in  FIG. 8  and  FIG. 9 . A first embodiment for a process for producing a product of the composite sheet structure of the present invention is presented, and the process includes the steps of: 
     (a) Mix some foaming agents and blowing promoters with a substrate, and then put the substrate which is mixed with the foaming agents and the “blowing promoters” (A raw material for the manufacture of plastics, for example, urea-formaldehyde resin) into an extruder  41 . The extruder  41  grinds, heats and extrudes the substrate to become an extruded liquid bar, and then the liquid bar are transported to a mold  42  to be flatten and become a core layer of the product, and then the core layer is cooled via a cooling apparatus (not shown). Wherein the kind of the substrate, the kinds of the foaming agents and the blowing promoters are not restricted. The substrate can be made of polyethylene, or polypropylene, or ethylene-vinyl acetate copolymer, the foaming agents can be made of diazenedicarboxamide, and the blowing promoter can be made of a zinc oxide or stearin cadmium. 
     (b) Apply adhesives (polymer film or liquid adhesive) onto the surfaces of the core layer by two adhesive applying units  43  with different feeding positions (top and bottom), the adhesives are the lamination agent of the product, and the kinds of the adhesives are not restricted. 
     (c) Provide two composite sheets  3 , and the two composite sheets  3  are coiled around two coiling rollers  44  with different vertical positions (top and bottom). Uncoil the two composite sheets  3 , and the composite sheets  3  are transported to a forming roller group  45 . The forming roller group  45  presses the composite sheets  3  to contact with the bonding layers, the composite sheets  3  are laminated to the core layer, the core layer is sandwiched between the two composite sheets  3 , and the two composite sheets  3  are two surface layers of the product respectively. Furthermore, the two surface layers can be coated with many colors. 
     (d) cool the product via a cooling unit  46 . 
     (e) guide the product to leave the cooling unit  46  via a guiding unit  47 . 
     (f) the guiding unit  47  guilds the product to move to a cutting unit  48 , and the cutting unit  48  cut the product to length. 
     As shown in  FIG. 10 . A process for producing a composite sheet structure of the second embodiment is presented. The process of  FIG. 10  is similar to that of  FIG. 8  with the following difference regarding and in place of  FIG. 8 . Please view in conjunction with  FIG. 9 , providing an adhesive supply connecting with an adhesive shunt (not shown) which is between the mold  42  and the forming roller group  45 . The adhesive shunt has two runners with different feeding positions (top and bottom). After the core layer is formed after the mold  42 , the two runners output and coat the adhesives to both surfaces of the core. The adhesives are the lamination agents for surface metals of the product. 
     As shown in  FIG. 11 . A process for producing a product of the composite sheet structure of the third embodiment according to the present invention is presented. Similar to steps of  FIG. 8  with the following difference regarding and in place of  FIG. 8  ( b ); please view in conjunction with  FIG. 9 : Provide some adhesive films. Place the adhesive films on the surfaces of the core layer, and heat and press the adhesive films by a set of heating rollers (could be forming roller group  45  or a separate set of heating rollers) having high temperature, and the adhesive films are found in-between the core &amp; surface composite sheets to become adhesives, and the adhesives are the bonding layers of the product. As shown in  FIG. 12 . A process for producing a product of the forth embodiment of the composite sheets is presented: Provide the flat core layer made of polyethylene, or polypropylene, or ethylene-vinyl acetate copolymer. Provide the two flat surface layers made of composite sheets  3 . Bend the core layer and the two surface layers by a beating tool, a punching tool, a stamper, or a roller group to become fretted or flexuous sheets, each metallic sheet  1  of the surface layers includes a plurality of first base portions, a plurality of second base portions, and a plurality of bending portion, each first base portion&#39;s vertical position is different from each second base portion&#39;s vertical position (for a visualization of what an embodiment of difference between base portion&#39;s vertical position, please see  FIG. 15 ), and the bending portions are connected between the first base portions and the second base portions respectively, and the bonding power between the bended core layer and the bended surface layers are strengthened. 
     As shown in  FIG. 13 . A process for producing a product of the fifth embodiment of the composite sheets is presented. Provide the core layer made of the composite sheet  3 . Provide the two flat surface layers made of composite sheets  3 . Bend the core layer by the beating tool, the punching tool, the stamper or the roller group to become a fretted or flexuous sheet, and each metallic sheet  1  of the core layer includes a plurality of first base portions, a plurality of second base portions, and a plurality of bending portion, the bending portions are connected between the first base portions and the second base portions respectively, the vertical position of each first base portion is different from the vertical position of each second base portion. One of the two surface layers bonds with the first base portions, and the other surface layer bonds with the second base portions. 
     As shown in  FIG. 14 . A composite sheet structure is presented, and the composite sheet structure includes a core layer  5 , two surface layers  6  and a plurality of bonding layers  7 . The core layer  5  and the surface layers  6  are three flat sheets. The core layer  5  is sandwiched between the two surface layers  6 , the core layer  5  is made of polyethylene, or polypropylene, or ethylene-vinyl acetate copolymer, and each surface layer  6  has a plurality of metallic sheets  61 . The bonding layers  7  are made of adhesives. One of the bonding layers  7  are mounted between the metallic sheets  61  and the core layer  5 , and the other bonding layers  7  are mounted between the two metallic sheets  61  and bonds the metallic sheets  61  and core layer  5  together. 
     As shown in  FIG. 15 . A second embodiment of the composite sheet structure is presented. And the second embodiment of the composite sheet includes a core layer  5 ′, two surface layers  6 ′ and a plurality of bonding layers  7 ′. The core layer  5 ′ and the surface layers  6 ′ are fretted or flexuous sheets. The core layer  5 ′ is sandwiched between the two surface layers  6 ′, the core layer  5 ′ is made of polyethylene, or polypropylene, or ethylene-vinyl acetate copolymer, and each surface layer  6 ′ has a plurality of metallic sheets  61 ′. Each metallic sheet  61 ′ includes a plurality of first base portions  611 ′, a plurality of second base portions  612 ′, and a plurality of bending portion  613 ′, the bending portions  613 ′ are connected between the first base portions  611 ′ and the second base portions  612 ′ respectively, the vertical position of each first base portion  611 ′ is different from the vertical position of each second base portion  612 ′. The bonding layers  7 ′ are made of adhesives. Two of the bonding layers  7 ′ are mounted between the metallic sheets  61 ′ and the core layer  5 ″, and the other bonding layers  7 ′ are mounted between the two metallic sheets  61 ′, wherein the bonding layers  7 ′ bonds the metallic sheets  61 ′ and core layer  5 ′ respectively. 
     As shown in  FIG. 16 . A third embodiment of the composite sheet structure is presented. And the third embodiment of the composite sheet includes a core layer  5 ″, two surface layers  6 ″ and a plurality of bonding layers  7 ″. The core layer  5 ″ is a flexuous sheet. The core layer  5 ″ is sandwiched between the two surface layers  6 ″, the core layer  5 ″ has a plurality of metallic sheets  51 ″, and each metallic sheets  51 ″ includes a plurality of first base portions  511 ″, a plurality of second base portions  512 ″, and a plurality of bending portion  513 ″, the bending portions  513 ″ are connected between the first base portions  511 ″ and the second base portions  512 ″ respectively, the vertical position of each first base portion  511 ″ is different from the vertical position of each second base portion  512 ″ (in the shape of a square wave function as can be seen from  FIG. 16 ). The surface layers  6 ″ are two flat sheets, and each surface layer  6 ″ has a plurality of metallic sheets  61 ″. The bonding layers  7 ″ are made of adhesives. One of the bonding layers  7 ″ are mounted between the metallic sheets  61 ″ and the core layer  5 ″, and the other bonding layers  7 ″ are mounted between the metallic sheets  51 ″ of the core layer  5 ″ and the metallic sheets  61 ″ of the surface layer  6 ″ respectively. 
     As shown in  FIG. 17 . A forth embodiment of the composite sheet structure is presented, and the forth embodiment of the composite sheet includes two core layers A and a plurality of bonding layers B, the two core layers A are one flexuous sheet and one flat sheet, and each core layer A has a plurality of metallic sheets, and the metallic sheets bond with one another via some of the bonding layers B. The flexuous sheet includes a plurality of first base portions A 1 , a plurality of second base portions A 2 , and a plurality of bending portion A 3 , The bending portions A 3  are connected between the first base portions A 1  and the second base portions A 2  respectively, the vertical position for all the first portions A 1  and the second portions A 2  are different, and the second base portions A 2  bond with the flat sheet via one of the bonding layers B which is between the flexuous sheet and the flat sheet. 
     As shown in  FIG. 18 . A fifth embodiment of the composite sheet structure is presented. The number of the core layer A is two, and the core layers A are two flexuous sheets, and each core layer A are made of metallic sheets, and the metallic sheets bond with one another via some of the bonding layers B. Each flexuous sheet includes the first base portions A 1 , the second base portions A 2 , and the bending portion A 3 . The first base portions A 1  of one of the flexuous sheets bond with the second base portions A 2  of the other flexuous sheet via one of the bonding layers B which is between the two flexuous sheets. 
     As shown in  FIG. 19 . A sixth embodiment of the composite sheet structure is presented, The number of the core layer A is three, and the core layers A are two flexuous sheets and one flat sheet. Each core layer A are made of metallic sheets, and the metallic sheets bond with one another via some of the bonding layers B. Each flexuous sheet includes the first base portions A 1 , the second base portions A 2 , and the bending portion A 3 . The first base portions A 1  of one of the flexuous sheet and the second base portions A 2  of the other flexuous sheet bond with the flat sheet via two of the bonding layers B which are among the two flexuous sheets and the flat sheet respectively. 
     The present invention has the following characteristics: Even the metallic sheets  1  are not generally made of more expensive metals, the strength of the composite sheet  3  should still satisfy industry safety regulation, the cost of producing the composite sheet  3  can be effectively reduced, the weight of the composite sheet  3  can be light when compared to using traditional method, so that it is very convenient for users to assemble many of the composite sheets  3 . 
     The description above only illustrates specific embodiments and examples of the invention. The invention should therefore cover various modifications and variations made to the herein-described structures and applications of the invention provided if they fall within the scope of the invention as defined in the following appended claims.