Patent Publication Number: US-6342115-B1

Title: Laminating heating module

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     (Not Applicable) 
     STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
     (Not Applicable) 
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to lamination equipment for adhesively heat laminating two lengths of fabric to each other to form a laminated fabric product, and in particular to a flatbed fabric lamination machine having heating modules operative to adjust the heat applied to the fabric across the length of the heating module. 
     Fabric lamination is an extremely important process in the production of a myriad of goods. Such lamination generally involves the bonding of adjacent surfaces of two lengths of different textile products to each other with heat-sensitive adhesive. The two lengths typically are fed into a fabric lamination machine where both heat and physical pressure are applied to consequently activate the adhesive and bond the lengths of textile products together to form the laminated fabric product. Non-limiting examples of such laminated fabric products include garments with backings, wadding, decorative panels, carpets and draperies with backings and linings, furniture upholstery and bedding covers, and scores of other domestic and industrial commodities. 
     While fabric lamination machines are known in the art, these machines provide a single conveyor belt system of two rotating belts between which two lengths of fabric travel and are laminated by opposing pressured rollers after the lengths of the fabric are heated to a lamination temperature during belt travel in a heating zone. After such lamination, the resulting laminated product is cooled and made available for final use. The belts are heated in the heating zone through the use of upper and lower heater banks. Each upper and lower heater bank comprises a plurality of heater modules which provide heat to a respective moving conveyor belt. In this regard, the heater modules of the upper heater bank are positioned immediately above and in contact with the upper laminator conveyor belt, while the heater modules of the lower heater bank are positioned immediately below and in contact with the lower laminator conveyor belt. Typically, the heater modules comprise elongate rectangular extrusions that are placed laterally across the conveyor belt. Specifically, the heater modules are perpendicular to the direction of travel of the conveyor belt such that heat is directed across the width of the fabrics being laminated. 
     In heat lamination machines, the transfer of heat to the conveyor belt and the fabric must be uniform from the heater module in order to ensure a proper bond between the two textiles. Typically, in prior art heat lamination machines, the heating modules contain electric heating rods within three zones which transfer heat to the rectangular extrusion. However, the placement of the heating rods create “hot spots” within the extrusion which are undesirable. The “hot spots” are areas along the extrusion that do not have the desired temperature. Additionally, prior art heating modules do not allow for a prescribed temperature variation across the length of the extrusion. Specifically, the heating rods are placed across the length of the extrusion such that the heating module has the same temperature throughout the length thereof. Accordingly, it is not possible to vary the temperature in different zones of the heating module as may be necessary for the bonding of certain fabrics. 
     The present invention addresses the deficiencies in the prior art heat lamination machines by providing a heating module for a heat lamination machine that can accurately control the temperature of the conveyor belts. In this regard, the heating modules of the present invention evenly transfer heat across the width of the conveyor belts. The heating module of the present invention additionally provides lateral control of heat across the width of the conveyor belt for more precise control. 
     BRIEF SUMMARY OF THE INVENTION 
     In accordance with the preferred embodiment of the present invention, there is provided a laminating heating module for use in a flatbed laminating machine. The heating module comprises an elongate body portion having an interior chamber and a bottom wall. Typically, the body portion has a rectangular cross-sectional configuration. Disposed within the interior chamber on the bottom wall is an electric heating pad fabricated from silicone rubber and container a nickel-chrome heating element to provide uniform heat. The heating pad has three separate heating zones in order to provide lateral control of heat dissipation across the heating module. Attached to the heating pad at each respective heating zone is a thermocouple. Each thermocouple regulates the temperature of each of the heating zones. The heating module further includes a thermostat attached to the heating pad and operative to control the temperature of the heating zones to protect the heating pad from overheating. 
     Additionally, the present invention provides a method of regulating heat to a laminating heating module constructed in accordance with the preferred embodiment. The method comprises supplying electricity to the heating pad in order to heat such. Next, the temperature of each heating zone is regulated with a respective thermocouple. Finally, the temperature of the heating pad is protected with the thermostat. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These as well as other features of the present invention, will become more apparent upon reference to the drawings wherein: 
     FIG. 1 is a cross-sectional view of a heat laminating machine having heating modules constructed in accordance with the preferred embodiment of the present invention; 
     FIG. 2 is a perspective view of a heating module used in the heat laminating machine shown in FIG. 1; and 
     FIG. 3 is a cut-away perspective view of the heating module shown in FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings wherein the showings are for purposes of illustrating preferred embodiments of the present invention only, and not for purposes of limiting the same, FIG. 1 perspectively illustrates a heat laminating machine  10  used to manufacture laminated textile and wood products. The machine  10  includes a first roll  12  of a first material  14  disposed adjacent to an intermediate belt  16  that moves the first material under a scatterer  18 . The scatterer  18  is positioned above the intermediate belt  16  and first material  14  and is operative to transfer an electrostatic powder onto a top surface of the first material  14  subsequent to the same being unrolled from the first roll  12 . The intermediate belt  16  further moves the first material  14  into an infrared oven  20 . The infrared oven  20  is disposed above the intermediate belt  20  and first material  14  in order to cure the powder on the first material  14 . The powder may be an adhesive or other type of material and/or protectant. It will be recognized to those of ordinary skill in the art, that the scatterer  18  and infrared oven  20  are optional items that are not necessary for the proper operation of the machine  10 . 
     The machine  10  is used to laminate the first material  14  to a second material  24 . In this regard, the machine  10  further includes a second roll  26  of the second material  24 , the second roll  24  being disposed above the first material  14 . Upon being unrolled from the second roll  26 , the second material  24  is passed over a pre-heater  22 . The pre-heater  22  directs heat toward the bottom surface of the second material  24  in order for the second material  24  to reach a prescribed initial temperature. 
     After the second material  24  is heated to an initial temperature by pre-heater  22 , the second material  24  is placed on the top surface of the first material  14  via an upper conveyor belt  28  and a lower conveyor belt  30 . The upper and lower conveyor belts  28  and  30  are positioned within the heat laminating machine such that the bottom surface of the second material  24  is in laminar juxtaposition with the top surface of the first material  14 . The width of each conveyor belt  28 ,  30  is greater than the width of the first material  14  and/or second material  24  in order to fully bond them together. The upper and lower conveyor belts  28 ,  30  additionally heat the first and second materials  14 ,  24  in order to heat activate any adhesive bond. As seen in FIG. 1, the upper conveyor belt  28  is in contact with an upper heater bank  32 . The upper heater bank  32  comprises a series of heating modules  34  that are in contact with the upper surface of the upper conveyor belt  28  and supported by a rigid upper support frame  36 . The upper support frame  36  positions the heating modules  34  in contact with the upper conveyor belt  28 . The upper support frame  36  is attached to the heat laminating machine through two pneumatic pressure mechanisms  37 ,  37 . The pressure mechanisms  37 ,  37  exert pressure against the upper support frame  36  to ensure that an air gap does not exist between the heating modules  34  and the upper conveyor belt  28 , thereby leading to consistent heat transfer between the heating modules  34  and the upper conveyor belt  28 . 
     As seen in FIG. 2, each of the heating modules  34  comprises an elongate, tubular body portion  38  having a top wall  40 , a bottom wall  42 , a left side wall  44 , a right side wall  46  and an interior chamber  48  defined thereby. The top wall  40  is formed to include an opposed pair of channels  50  that are configured to receive the support frame  36 . In this regard, the upper support frame  36  is preferably an elongate, rectangular tube, with the channels  50  being formed to have a complementary configuration such that the channels  50  can receive the upper support frame  36  and support the heating module  34 . The body portion  38  has a length that is approximately equal to the width of the upper conveyor belt  28  thereby allowing each heating module  34  to laterally traverse the entire width of the upper conveyor belt  28  and provide heat fully across the same. 
     In the preferred embodiment of the present invention, each heating module  34  includes a heating pad  52  disposed on the inner surface of the bottom wall  42 . The heating pad  52  is fabricated from silicone rubber and preferably has heating elements fabricated from nickel-chrome that are capable of electrically heating the bottom wall  42  of the body portion  38 . The heating elements are electrically connected to a power cord  56  that transmits electrical power to the heating pad  52  that converts such electrical power to thermal energy. The silicone rubber of the heating pad sufficiently disperses the heat from the nickel-chrome heating elements such that bottom wall  42  of the heating module  34  can be uniformly heated without hot spots. The heating pad  52  is segregated into three zones  54   a ,  54   b ,  54   c , along the length of the body portion  38  of heating module  34 , as seen in FIG.  3 . The temperature of each of the zones  54   a ,  54   b , and  54   c  can be independently monitored by respective thermocouples  58   a ,  58   b ,  58   c . Each of the thermocouples  58   a ,  58   b , and  58   c  are attached to the heating pad  52  in a respective zone  54   a ,  54   b , and  54   c  and can monitor and control the temperature of such through the use of an electronic temperature controller (not shown). Each thermocouple  58   a ,  58   b , and  58   c  is configured to regulate the heat dissipated by each of the zones  54   a ,  54   b  and  54   c  such that the temperature of each zone  54   a ,  54   b , and  54   c  can vary according to the type of materials being bonded. Further, attached to the heating pad  52  is a thermostat  60  operative to protect the heating pad  52  from overheating due to failure of the thermocouples  58   a ,  58   b  and  58   c  or the electronic temperature controller. If the temperature of the heating pad  52  exceeds 400° F. at the location of the thermostat  60 , then the thermostat  60  will remove power to all three zones  54   a ,  54   b , and  54   c  of the heating pad  52 . As seen in FIG. 3, the heating pad  52  includes three zones  54   a ,  54   b , and  54   c . However, it will be recognized to those of ordinary skill in the art that the pad  52  may include a fewer or greater number of zones depending upon the application. 
     As seen in FIG. 1, the heat laminating machine  10  comprises a lower heater bank  62  to transfer heat to the lower conveyor belt  30 . The lower heater bank  62  is identically configured to the upper heater bank  32  and comprises six heating modules  34  attached to a lower support frame  64 . As will be recognized by those of ordinary skill in the art, the number of heating modules  34  may vary, but the lower heater bank  62  and the upper heater bank  32  should contain the same number. The lower support frame  64  positions each of the heating modules  34  in abutting contact with the lower surface of the lower conveyor belt  30 . The heating modules  34  therefore heat the lower conveyor belt  30  to a predetermined temperature in order to bond the first material  14  to the second material  24 . The heating modules  34  of the lower heater bank  62  can control the temperature across the width of the lower conveyor belt  30  in order to ensure proper bonding as previously described for the upper conveyor belt  28 . 
     The heat laminating machine  10  further includes a pressure roller  66  for applying pressure to the first material  14  and the second material  24  after heating thereof. The pressure roller  64  is disposed adjacent to the upper conveyor belt  28  and subsequent to the heating of the first material  14  and the second material  24 . The pressure roller  64  ensures that the first material  14  is properly bonded to the second material  24 . 
     Disposed adjacent to the pressure roller  64  and the lower conveyor belt  30  is an upper cooling conveyor belt  68  and a lower cooling conveyor belt  70 . The upper and lower cooling conveyor belts  68  and  70  are positioned in the machine  10  to cool the first and second material  14  and  24  subsequent to heating and application of pressure by pressure roller  64 . The upper and lower cooling conveyor belts  68  and  70  cool the first material  14  and the second material  24  in order to adhesively bond such together. In this regard, the laminating machine  10  further includes a series of cooling modules  72  in contact with the upper cooling conveyor belt  68  and the lower cooling conveyor belt  70 . The cooling modules  72  are operative to cool the upper and lower conveyor belts  68  and  70  to a prescribed temperature and may be cooling tubes that contain a cooling fluid. After the first material  14  and the second material  24  have been cooled, the first material  14  and the second material  24  are bonded together to form the final product. 
     Additional modifications and improvements of the present invention may also be apparent to those of ordinary skill in the art such as varying the number of heating modules  34 . Thus, the particular combination of parts described and illustrated herein is intended to represent only certain embodiments of the present invention, and is not intended to serve as limitations of alternative devices within the spirit and scope of the invention.