Abstract:
A controller for a hot melt adhesive dispensing system has a main circuit board and power modules which are removably received on a controller enclosure. The power modules are directly couplable with the main board and with cord sets from heated hoses of the dispensing system, eliminating the need for wiring harnesses to be routed between these components. Accordingly, the main board and power modules may be readily removed and replaced in the field to permit efficient servicing and modification of the system to accommodate the needs of various applications.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention pertains to dispensing systems for dispensing flowable material, and more particularly to hot melt adhesive dispensing systems.  
         BACKGROUND OF THE INVENTION  
         [0002]    Thermoplastic adhesives, otherwise known as “hot melt” adhesives, have been widely used in industry for adhering many types of products. Hot melt adhesive dispensing systems generally include one or more adhesive dispensing guns, heated hoses connected to the guns, and a dispensing unit for melting and supplying liquid adhesive to the guns through the heated hoses. The dispensing units of conventional hot melt adhesive systems can include a tank and heater, a pump, a manifold, and a controller. The manifold has an inlet connected to the tank and has multiple outlet ports for fluid connection to the heated hoses. Adhesive material is supplied to the tank in solid or semi-solid form, where it is melted and heated by the heater. A pump associated with the tank and manifold pumps liquid adhesive from the tank, through the manifold and heated hoses to the dispensing guns. The controller is generally located adjacent the tank and controls the power supplied to the heater and heated hoses to maintain the liquid adhesive at an appropriate viscosity and temperature according to the desired application.  
           [0003]    The controller generally includes a main board which performs the power distribution functions of the dispensing system. In addition to the main board, the controller will generally include a CPU board and one or more power modules which are coupled with the main board and with the heated hoses. The controller is typically configured to be used with a predetermined number of guns and hoses (for example 2, 4, or 6 hoses). Users of adhesive dispensing systems often desire to upgrade the systems from, for example, two hose systems to four hose systems, or from four hose systems to six hose systems. However, the configuration of conventional controllers makes upgrading or other modification of the controller costly and very labor intensive. For example, the main board and power modules are typically housed in an enclosure and are coupled together by individual wiring harnesses. The power modules are in turn coupled to cord sets of the hoses using additional wiring harnesses. Accordingly, upgrading a conventional controller involves accessing the main board and power modules, uncoupling the associated wiring harnesses, removing the main board and power modules, installing a new main board and new power modules, and routing and connecting the new wiring harnesses. Furthermore, with some systems upgrading is not even possible.  
           [0004]    In some applications, it may be desired to provide improved resistance to liquid infiltration into the controller. Such infiltration may occur, for example, by accidental spillage of liquid near the adhesive dispensing system, or by exposure to liquids during cleaning of the adhesive dispensing system or the immediate area surrounding the system. In these situations, it is desirable to prevent infiltration of liquids into the controller to prevent damage to electrical components contained therein.  
           [0005]    The electrical components that make up the controller generate heat which must be dissipated to prevent overheating of the controller. Generally, heat sinks are added to conventional controllers to aid in the thermal management of the controller. However, fabricating or purchasing separate heat sinks and installing them on the controller represent additional costs which could be reduced or eliminated if a more efficient means of dissipating heat could be utilized.  
           [0006]    There is thus a need for an improved controller which can be used with hot melt adhesive dispensing systems and which permits ready modification of the controller in the field for servicing or upgrading. There is also a need for a controller which provides improved resistance against liquid infiltration and simplifies the hardware required for thermal management.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention provides a controller for use with a hot melt adhesive dispensing system that facilitates quick and easy removal and replacement of a main circuit board and power modules associated with the controller, whereby the controller may be readily serviced or reconfigured in the field. In this regard, the main board and power modules are removably received on an enclosure which houses the various components of the controller. In an exemplary embodiment, the main board and power modules are slidably received on the enclosure. The main board and power modules are provided with respective electrical sockets which permit the power modules to be coupled by plugging directly to the main board without the need for wiring harnesses which are used in conventional controllers. Accordingly, the power modules and main board may be coupled and uncoupled simply by sliding the components on the enclosure to engage or disengage one another. No routing and rerouting of wiring harnesses is required.  
           [0008]    In another exemplary embodiment, the power modules are configured to be directly connected to cord sets associated with heated hoses of the adhesive dispensing system. This configuration eliminates the need for a connector plate and wiring harnesses between the cord sets and power modules, as is typical of conventional controllers, thereby further facilitating ready removal and replacement of power modules in the field.  
           [0009]    In yet another exemplary embodiment, the power modules are mounted to side panels that have heat dissipating fins provided on an outer surface of the panels, whereby thermal management of the controller may be achieved without the need for additional heat sinks to be attached to the controller.  
           [0010]    In another exemplary embodiment, the enclosure and the removable side panels to which the main board and power modules are mounted are configured to form tongue-and-groove joints at their interfaces, whereby the interior of the controller may be sealed against moisture infiltration.  
           [0011]    These and other features and objectives of the present invention will become more readily apparent from the following Detailed Description taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description given below, serve to explain the invention.  
         [0013]    [0013]FIG. 1 is a schematic drawing of a hot melt adhesive system including an exemplary controller of the present invention;  
         [0014]    [0014]FIG. 2 is an exploded perspective view of an exemplary controller of the present invention;  
         [0015]    [0015]FIG. 3 is a side view of the controller of FIG. 2 taken along line  3 - 3  of FIG. 2 and depicting sockets for coupling with hose cord sets;  
         [0016]    [0016]FIG. 4 is a partial section view of the controller of FIG. 3, taken along line  4 - 4  of FIG. 3;  
         [0017]    [0017]FIG. 5 is a partial section view of the controller of FIG. 3, taken along line  5 - 5  of FIG. 3;  
         [0018]    [0018]FIG. 6 is a partial section view of the controller of FIG. 3, taken along line  6 - 6  of FIG. 3; and  
         [0019]    [0019]FIG. 7 is a partial section view of the controller of FIG. 3, taken along line  7 - 7  of FIG. 3. 
     
    
     DETAILED DESCRIPTION  
       [0020]    Referring to FIG. 1, a hot melt adhesive system  10  is shown, including a dispensing unit  12  which incorporates an exemplary controller  14  according to the present invention. The dispensing unit  12  further includes a tank  16  for receiving and melting solid or semi-solid adhesive material, a manifold  18  connected to the tank  16 , and a pump  19 . The tank  16  comprises side walls  20  defining a tank interior  22 , a removable cover  24 , and a base  26  which includes a tank heater  28  for melting and heating the adhesive material  30  in the tank  16 . A tank outlet  32  proximate the base  26  is coupled to a passage  34  which connects to an inlet  36  of the manifold  18 . The pump  19  is coupled to the manifold  18  and pumps liquid adhesive  30  from the tank  16  and into the manifold  18  where it is split into separate flows. The manifold  18  has a plurality of outlet ports  38  which may be fitted with heated hoses  40  attached to one or more adhesive guns  44  to supply the liquid adhesive to the guns  44 . The guns  44  include one or more adhesive dispensing modules  46  which apply the adhesive  30  to a desired product (not shown). The adhesive dispensing modules  46  are mounted to gun bodies  48  having gun heaters  49  and are supported on a frame  47 . The hot melt adhesive system  10  shown in FIG. 1 includes two guns  44 , one located on each side of the dispensing unit  12 , although it will be understood that different numbers of guns  44  arranged in different configurations may be used for a given adhesive system as required.  
         [0021]    With continued reference to FIG. 1, the controller  14  houses a power supply and electronic controls for the dispensing unit  12 . The heated hoses  40  are electrically coupled to the controller  14  by cord sets  42  associated with each hose  40  and plugged into sockets  45  on the controller. The controller  14  independently monitors and adjusts the tank heater  28 , the heated hoses  40 , and the gun heaters  49  to melt solid adhesive received into the tank  16  and to maintain the temperature of the melted adhesive  30  to ensure proper viscosity of the adhesive  30  supplied to the guns  44  and dispensed by the adhesive dispensing modules  46 .  
         [0022]    Referring to FIG. 2 there is shown an exploded view of the exemplary controller  14  of FIG. 1. The controller  14  comprises an enclosure  50  which houses the various electronic components that control the operation of the dispenser  12 , including a main board  52  and one or more power modules  54 ,  56  configured with conventional electronic devices  57  as is known in the art. The power modules  54 ,  56  further include individual power relays  55  which are configured to switch power only to those hoses  40  and guns  44  which plug into the respective modules  54 ,  56 . These dedicated relays  55  eliminate the need for a large, central contactor which, in conventional systems, must be capable of switching power to all heaters of a dispensing system whether or not a given heater is actually present. Accordingly, the dedicated relays  55  may be compact in size and eliminate the additional cost associated with having a larger relay than is necessary for a given task.  
         [0023]    The enclosure  50  further includes a base  58  and a top panel  60  connected to vertical frame members  62  by fasteners (not shown) received through apertures  61  in the top panel  60  and corresponding apertures (not shown) in the base  58 . Advantageously, the main board  52  and the power modules  54 ,  56  are removably received onto the enclosure  50  whereby the main board  52  and/or modules  54 ,  56  may be easily removed and replaced for convenient servicing and/or reconfiguration of the controller  14 . In the exemplary embodiment shown, the base  58 , top panel  60 , and vertical frame members  62  of the controller enclosure  50  have grooves  64  formed along their side edges to serve as rails for slidably receiving side panels  68 ,  70 ,  72 , which form the exterior sides of the enclosure  50  and to which the main board  52  and power modules  54 ,  56  are mounted. A front panel  74  is received on the enclosure  50 , adjacent side panels  68 ,  70 ,  72 , by a flanged edge  79  engageable with a vertical frame member  62  and secured by a fastener  81  engageable with aperture  83  on another frame member  62  to complete the exterior shell of the enclosure  50 .  
         [0024]    With reference to FIGS. 2 and 4- 7 , there are shown detailed views of the interfacing portions of the edges of the side panels  68 ,  70 , and  72  with the grooves  64  formed into the base  58 , top panel  60 , and vertical frame members  62 . As illustrated in the figures, the adjacent components form tongue-and-groove joints which, in an exemplary embodiment, seal the interior of the enclosure  50  against liquid infiltration which may occur, for example, by exposure to liquids during cleaning of the adhesive system  10  or due to an accidental spillage of liquid near the controller  14 .  
         [0025]    [0025]FIG. 4 shows detail of the tongue-and-groove joint formed between a first section  72   a  of side panel  72  and base  58 . As shown therein, a lower edge of first section  72   a  has a U-shaped section  71  which mates with groove  64  in the base  58 . A similar U-shaped section  69  is provided at a lower edge of a first section  70   a  of side panel  70  and forms a groove  73  that receives a top edge  75  of first section  72   a  of panel  72 , as shown in FIG. 5. Likewise, the top edge  77  of first section  70   a  of side panel  70  is received in groove  64  provided in the top panel  60 , as shown in FIG. 6. The interfaces of side panel  68  and first section  70   a  of panel  70  with vertical frame member  62  is shown in FIG. 7, where side panels  68  and first section  70   a  are received in grooves  64  of vertical frame member  62 .  
         [0026]    Referring to FIG. 2, second sections  70   b ,  72   b  of side panels  70  and  72 , respectively, have respective top and bottom edges  94 ,  96  which abut corresponding ledges  98 ,  100  formed into the top panel  60  and base  58 , respectively, to further seal the enclosure  50 . Side panels  70 ,  72  are secured to vertical frame member  62  by fasteners  102  through apertures  104  in the vertical frame member  62 .  
         [0027]    With continued reference to FIG. 2, the main board  52  and power modules  54 ,  56  are mounted to respective side panels  68 ,  70 ,  72 , which may be received in the rails of the enclosure  50 . In contrast to conventional controllers, the power modules  54 ,  56  of the present invention are configured to be directly coupled with the main board  52  by respective connectors  80 ,  82  on the power modules  54 ,  56  and connectors  84 ,  86  on the main board  52 , as further illustrated in FIGS.  4 - 7 . As shown in the figures, connector  80  on power module  54  couples with connector  84  on the main board  52 , and connector  82  on power module  56  couples with connector  86  on the main board. To facilitate the coupling of connectors  80 ,  82 ,  84 ,  86 , pins  92  are provided on connectors  84  and  86  on main board  52  to help guide connectors  80 ,  82  on the power modules  54 ,  56  into position. This direct coupling of components thereby eliminates the need for intermediate wiring harnesses to connect the power modules  54 ,  56  to the main board  52 . The simplified design facilitates interchangeability of various power modules  54 ,  56  with the main board  52  for quick and easy replacement of the components as may be required for service or reconfiguration of the controller  14 .  
         [0028]    As illustrated in FIG. 2, the panel  68  supporting the main board  52  may be received between the base  58  and top panel  60  to form one side of the enclosure  50  while one or more panel sections  70 ,  72 , to which the power modules  54 ,  56  are mounted, may be received between the base  58  and top panel  60  to form an adjacent side of the enclosure  50 . The front panel  74  of the enclosure  50  supports a CPU (not shown) in a manner similar to that depicted for main board  52  on side panel  68 . Front panel  74  further includes a control interface  88  configured to receive input from a user and to display information regarding the operation of the controller  14 .  
         [0029]    The power modules  54 ,  56  include various electronic components which generate heat. To facilitate the dissipation of heat from within the enclosure  50 , the side panels  70 ,  72  to which the power modules  54 ,  56  are mounted are formed with several heat dissipating fins  90  disposed on the outer portions of the side panels  70 ,  72 . Advantageously, this configuration eliminates the need for a separate heat sink to be added to the controller  14 , as is typical of conventional designs.  
         [0030]    Referring now to FIG. 3, there is shown a side view of the controller  14  depicting side panels  70 ,  72 , which support first and second power modules  54 ,  56  installed onto the enclosure  50 . As shown in the figure, electrical sockets  45  are provided on side panels  70 ,  72  whereby the hose cord sets  42  may be coupled directly to the power modules  54 ,  56 . This configuration eliminates the need for a connector plate and associated wire harnesses typically used in prior controllers to couple the hose cord sets  42  to the power modules. Because the sockets  45  are provided directly on the power modules  54 ,  56  and because the power modules  54 ,  56  are removable from the enclosure  50 , the controller  14  may be easily reconfigured to accommodate various dispensing system arrangements having different numbers of heated hoses  40  supplying adhesive to dispensing guns  44 .  
         [0031]    While the present invention has been illustrated by the description of various embodiments thereof, and while the embodiments have been described in considerable detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art.  
         [0032]    The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope or spirit of Applicant&#39;s general inventive concept.