Abstract:
Edges of panels, such as glass panels, are ground and polished using grinder wheels that are cooled and lubricated with a coolant. A coolant deflector is utilized to help prevent coolant, which may contain panel particles or abrasives, from entering between the panel and a conveying mechanism that transports the panel.

Description:
CROSS-SECTION TO RELATED APPLICATION 
     The present application claims priority to Provisional Application No. 61/528,490, filed Aug. 29, 2011, the entirety of which is incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The disclosed embodiments relate to a grinder coolant guard and coolant deflector for use in the manufacture of glass panels used in the construction of photovoltaic modules. 
     BACKGROUND 
     Glass panels are utilized in the manufacture of photovoltaic (PV) modules and are typically used as front and back covers of a module. One purpose of a glass panel used as a front cover of a PV module is to permit the transmission of sunlight to PV cells within the PV module. As is well known in the art, the PV cells convert the sunlight into electricity. Consequently, a PV module is more efficient if sunlight is transmitted to the PV cells with minimal obstructions. 
     Another purpose of the front cover, as well as the back cover, of a PV module is to protect the PV cells within the module from external environmental conditions. Exposure of the PV cells to external environmental conditions may shorten the productive life of the PV module. A further purpose of either the front or back cover is to be a foundation upon which the PV module is built. 
     Thus, it is desirable to prevent any defect from occurring in the glass panels as defects may cause the panels to fail to meet PV manufacturing specifications, in which case the panels may have to be discarded. These defects may impair the transmission of light to the PV cells, which may cause the PV module to operate inefficiently, and eventually expose the PV cells to external environmental conditions, which may hasten the end of the productive life of the PV module. Generally, before using the glass panels in the assembly of a PV module, grinder wheels are used to machine the panels down to their finished size and/or smooth or polish their edges to reduce edge defects. A coolant, for example water, is used to lubricate and cool the grinder wheels. The coolant constantly flows over the grinder wheels and incidentally flows onto the glass panels. Glass particles produced in the grinding process or abrasive particles from the grinder wheels may be collected in the coolant. If coolant containing glass or abrasive particles becomes trapped between a transporting conveyor mechanism and a glass panel, the particles can cause undesirable scratches or inclusions in the glass panel&#39;s surface. Thus, these undesirable particles need to be removed from the coolant lest they scratch the surface of the glass panels. However, removal of such particles requires additional manufacturing steps. 
     Accordingly, it is desirable to prevent coolant, which may contain glass or other abrasive particles, from overflowing onto a glass panel where the particles may become trapped between a conveyor mechanism and the glass panels or where the particles may come into contact with the surface of the glass panel upon which further processing will occur. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a top perspective view of a first embodiment. 
         FIG. 2  is a cut-away, top perspective view of the first embodiment. 
         FIG. 3  is a close-up, top perspective view of  FIG. 2 . 
         FIG. 3A  is a close-up, top perspective view of a second embodiment. 
         FIG. 3B  is a close-up, top perspective view of a third embodiment. 
         FIG. 3C  is a close-up, top perspective view of a fourth embodiment. 
         FIG. 4  is a cut-away, bottom perspective view of the first embodiment. 
         FIG. 5  is a cut-away, side view of the first embodiment. 
         FIG. 6  is a cut-away, top perspective view of a fifth embodiment. 
         FIG. 7  is a close-up, cut-away, top perspective view of the fifth embodiment. 
         FIG. 8  is a cut-away, bottom perspective view of the fifth embodiment. 
         FIG. 9  is a cut-away, side view of the fifth embodiment. 
         FIG. 9A  is a cut-away, side view of a sixth embodiment. 
         FIG. 9B  is a cut-away, side view of a seventh embodiment. 
         FIG. 9C  is a cut-away, side view of an eighth embodiment. 
         FIG. 9D  is a cut-away, side view of a ninth embodiment. 
         FIG. 9E  is a cut-away, side view of a tenth embodiment. 
         FIG. 10  is a cut-away, side view of an eleventh embodiment 
         FIG. 11  is a cut-away, top perspective of the eleventh embodiment. 
         FIG. 12  is a cut-away, top perspective view of a twelfth embodiment. 
         FIG. 13  is a cut-away bottom perspective view of a thirteenth embodiment. 
         FIG. 14  is a cut-away bottom perspective view of a fourteenth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which specific embodiments are illustrated that may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to make and use them. It is to be understood that structural, logical, or procedural changes may be made to the specific embodiments disclosed without departing from the spirit and scope of the invention. Other features, objects, and advantages will be apparent from the description, drawings, and claims. 
       FIG. 1  illustrates a perspective view of an exemplary grinder assembly  100  for grinding edges of a glass panel  110 . The glass panel  110  is positioned between conveyor belts  105 ,  106 , which move the glass panel  110  past grinder assembly  100 . A wheel box  130  is provided around a set of grinder wheels  120 . In one embodiment, the wheel box  130  is open at the back to permit access to the motors operating the grinder wheels  120  and to allow for coolant jets  190 , which spray coolant onto the grinder wheels  120 . In another embodiment, the wheel box  130  is closed on all sides with openings to permit insertion of the coolant jets  190  and spindles for the grinder wheels  120 . The wheel box  130  is also provided with an opening to allow the grinder wheels  120  to access the edge of the glass panel  110 . The wheel box  130  may be constructed of any suitable material known in the art such as rigid polymers, steel, aluminum, and other metal alloys. In some embodiments, transparent materials such as plexiglass may be used to allow the grinder wheels  120  to be safely observed while in operation. The wheel box  130  serves to contain coolant and debris and protect the glass panel  110  that is being ground. 
       FIG. 2  shows a partial cut-away view of the grinder assembly  100  of  FIG. 1 . A fender-type coolant deflector  115  is associated with a corresponding grinder wheel  120  and is utilized to deflect coolant away from conveyor belts  105 ,  106  and the surface of the glass panel  110 . The fender-type coolant deflector  115  is taller than its associated grinder wheel  120 . The fender-type coolant deflector  115  is positioned at an angle to the edge  165  of the glass panel  110 . In one embodiment, the fender-type coolant deflector  115  has a length such that the distance from the edge  165  of the glass panel  110  to the coolant deflector bridge  175  is between approximately one-half the radius of the grinder wheel  120  and approximately the radius of the grinder wheel  120 . 
     In the embodiment shown in  FIG. 2 , two opposing fender-type coolant deflectors  115  are positioned between paired sets of grinder wheels  120 , which rotate in opposite directions. Coolant jets  190  spray coolant onto the grinder wheels  120  in the direction of the coolant deflectors  115 . The grinder wheels  120  then direct the coolant spray towards the coolant deflectors  115 . Each coolant deflector  115  thereby serves as a shield between a grinder wheel  120  and the glass panel  110  and prevents the coolant from overflowing onto the glass panel  110  and becoming trapped between the conveyor belts  105 ,  106  and the glass panel  110 . 
     As is also shown in  FIG. 2 , a vertical coolant guard  125  may be provided to extend above the coolant deflectors  115 . The vertical coolant guard  125  reduces coolant ingress between glass panel  110  and conveyor belts  105 ,  106 . In one embodiment, the coolant deflectors  115  may be welded or otherwise affixed to the coolant guard  125 . In another embodiment, the coolant deflectors  115  may be welded or otherwise affixed to bottom plate  133  of the wheel box  130 . 
       FIGS. 1 and 2  also show a top rail  132  of the wheel box  130 , which reaches from the top edge of the vertical coolant guard  125  and extends above and partially over the grinder wheels  120  to provide further protection from the overflowing coolant. The top rail  132  is a portion of the frame for the wheel box  130  and provides support to the top lid  131  of the wheel box  130 , shown in  FIG. 1 . The top lid  131  may be made of plexiglass or other similar transparent materials if desired in order to allow the grinder wheels  120  to be observed safely while in operation. The top lid  131  may also be hinged to the top rail  132 . 
       FIG. 3  shows a close up of the grinder assembly  100  of  FIG. 2 . The coolant deflector  115  is provided with upper and lower tabs  145 ,  146  that define a notch  140  between them. The notch  140  is configured such that the edge of the glass panel  110  fits within the notch  140 . The upper and lower tabs  145 ,  146  extend above and below the glass panel  110  to reduce coolant ingress between the glass panel  110  and conveyor belts  105 ,  106 . 
     As is shown in  FIG. 3 , the fender-type coolant deflectors  115  are formed as opposing arcs spaced from the grinder wheels  120  and concentric with the grinder wheels  120 . In this embodiment, the opposing fender-type coolant deflectors  115  are connected by a coolant deflector bridge  175 . Depending on the distance between adjacent grinder wheels  120  and the desired distance between the coolant deflector  115  and the grinder wheel  120 , this element may be omitted and the coolant deflectors  115  connected directly. 
     In another embodiment, shown in  FIG. 3A , the fender-type coolant deflector  115   a  may be shaped as a flat plate and spaced parallel to a tangent of the circular grinder wheels  120 . In another embodiment, shown in  FIG. 3B , the fender-type coolant deflector  115   b  is arced to be both concentric to the grinder wheel  120  and have a top edge and bottom edge that arc and extend toward the top surface and bottom surface of the grinder wheel  120  respectively to further shield the glass panel  110  and conveyor belts  105 ,  106  from the coolant. In another embodiment, shown in  FIG. 3C , the grinder wheels rotate in the same direction and only one fender-type coolant deflector  115   c  is positioned between any two grinding wheels. In this embodiment, the fender-type coolant deflector  115   c  may be shaped in any of the forms described above. 
     The diameter of the wheels of the grinder assembly  100  is dependent upon the size and configuration of the glass panels to be ground. The fender-type coolant deflectors  115 ,  115   a ,  115   b ,  115   c  are proportioned relative to the size grinder wheels  120  utilized and of a sufficient height and length to deflect coolant spray as described herein. The coolant deflectors  115 ,  115   a ,  115   b ,  115   c  may be manufactured from any suitable material known in the art including suitably rigid polymers, steel, aluminum, and other metal alloys. 
     The conveyor belts  105 ,  106  shown in  FIG. 2  are configured to move the glass panel  110  continuously in the direction of arrow A past the grinder wheels  120 . A second grinder assembly  100  may be used to simultaneously grind the edge parallel to the edge that is being ground in  FIG. 2 . 
     An additional set of grinder assemblies  100  may be provided at a second grinding station. The additional set of grinders may be used to simultaneously grind the remaining two parallel sides of the glass panel. If other shaped glass panels  110  are utilized, an additional grinder assembly  100  may be provided for each additional side to be ground. 
       FIG. 4  shows a cut-away, bottom perspective view of the grinder assembly  100  in which the bottom plate  133 , shown in  FIG. 2 , and spindles of the grinder wheels  120  are omitted. In one embodiment, the coolant guard  125  may be provided with vertical slots  180  through which a bolt and wing nut  160  or similar fastener fixes the coolant guard  125  to the top rail  132  portion of the wheel box  130 . The vertical slots  180  allow the coolant guard  125  and associated deflector  115  to be raised or lowered as desired to adjust a desired clearance between the coolant guard  125 , deflector  115 , and the glass panel  110 . 
     As is also shown in  FIG. 4 , the coolant guard  125  may be provided with a channel  135  such that the coolant guard  125  has a “step” immediately above the glass panel  110 . The channel  135  provides stability to the coolant deflectors  115 , while still providing the grinder wheels  120  with access to the glass panel  110 . This also provides a location for the coolant deflector  115  to be mounted to the coolant guard  125 . 
       FIG. 5  shows the coolant deflector of  FIG. 4  from a side view. As is shown in  FIGS. 4 and 5 , the coolant deflectors  115  of  FIG. 2  may be mounted to the bottom plate  133 . To facilitate this, a bracket  195  is provided with a slot for a bolt  197  to mount the coolant deflector  115  to the bottom plate  133  of the wheel box  130 . This enables the coolant deflector  115  to be used without the coolant guard  125  if desired, or to allow the coolant deflector  115  to be easily exchanged with a differently configured coolant deflector  115  as desired. 
     The coolant guard  125  may be manufactured from any suitable material known in the art including rigid polymers, steel, aluminum, and other metal alloys. The coolant guard  125  may be manufactured from the same material as the coolant deflectors  115 ,  115   a ,  115   b ,  115   c  or from different materials as desired. 
     As is also shown in  FIG. 5 , opposing tabs  145 ,  146  of the coolant deflector  115  extend above and below the glass panel  110  to provide protection from coolant ingress between the belts  105 ,  106  and the glass panel  110 . The channel  135  of the coolant guard  125  is configured to receive the upper tab  145  of the coolant deflector  115 , and the upper tab  145  can be welded or mechanically fastened thereto. In another embodiment, the coolant deflector  115  can be formed such that the coolant deflector  115  is unitary with the coolant guard  125 . In one embodiment, a nut  161  may be welded within a channel  170  provided in the top rail  132 . This nut  161  provides an anchor location for a hinge with which to mount the top lid  131  of the wheel box  130 . 
       FIG. 6  shows a grinder assembly  100  from a top perspective view of another embodiment. In this embodiment, the coolant deflector is provided as a wiper-type coolant deflector  215   a  to prevent coolant from entering between the conveyor belts  105 ,  106  and the glass panel  110 . The wiper-type coolant deflector  215   a  is preferably made of flexible material. Nonetheless, it may be made of non-flexible material. The material from which the wiper-type coolant deflector  215   a  may be made includes ultra-high-molecular-weight polyethylene (UHMW), polyoxymethylene (Delrin), and silicone as well as other polymers. The wiper may have a thickness between 0.025 and 0.035 inches. 
       FIG. 7  shows a partial close up view of the grinder assembly  100  of  FIG. 6 . As is shown in  FIGS. 6 and 7 , the blade of the wiper-type coolant deflector  215   a  is against the surface of the glass panel  110  to stop the flow of coolant over the conveyor belts  105  and  106  and the glass panel  110 . 
     As can be better seen in  FIG. 8 , showing the wiper-type coolant deflector  215   a  from a bottom perspective view, coolant guard  125   a  has a “step” which defines a channel  135   a  at the edge  165  of the glass panel  110 . The wiper-type coolant deflector  215   a  may be mounted to the channel  135   a  of the coolant guard  125   a  at the edge  165  of the glass panel  110 . The wiper-type coolant deflector  215   a  is positioned to maintain contact with the glass panel  110  while providing minimal frictional resistance. 
       FIG. 9  shows an end view of the grinder assembly  100  of  FIG. 6 . In the embodiment of  FIG. 9 , the wiper-type coolant deflector  215   a  is mechanically fixed to the coolant guard  125   a . This may be accomplished by providing a tab  220   a , shown in  FIGS. 7 and 9 , that clips into a mating slot in the coolant guard  125   a  to affix the wiper-type coolant deflector  215   a  to the coolant guard  125   a . In another embodiment, the top rail  132  of  FIG. 9  may be configured to mount to a bracket  155  and provide a rest area  171  to receive the top lid  131 , shown in  FIG. 1 , which prevents the top lid  131  from sliding around the top of the wheel box  130 . 
     In one embodiment also shown in  FIG. 9 , the wiper-type coolant deflector  215   a  tilts away from the grinder wheel  120  such that the linear distance between the edge  216   a  contacting the glass panel  110  and the grinder wheel  120  is less than the linear distance between the edge  217   a  fixed to the coolant guard  125   a  and the grinder wheel  120 . By using this configuration, the force of the coolant spray from the grinder wheels  120  acts to force the edge  216   a  of the wiper-type coolant deflector  215   a  against the glass panel  110 . This creates a more effective seal between the wiper-type coolant deflector  215   a  and the glass panel  110 , which reduces coolant ingress between the glass panel  110  and the conveyor belts  105 ,  106 . 
     In another embodiment, shown in  FIG. 9A , the wiper-type coolant deflector  215   b  may be provided with a tab along its length configured to slide into a groove  210   b  on the coolant guard  125   b . In this embodiment, one end of the groove  210   b  is closed such that the frictional force of the glass panel  110  against the wiper-type coolant deflector  215   b  does not slide the wiper-type coolant deflector  215   b  out of the groove  210   b . In another embodiment, shown in  FIG. 9B , the wiper-type coolant deflector  215   c  may be formed unitary with the coolant guard  125   c . In another embodiment, the wiper-type coolant deflector  215   a  is fixed to coolant guard  125   a  by a suitable, water-resistant adhesive. 
     As is also shown in  FIG. 9 , the wiper-type coolant deflector  215   a  is provided on only the top side of the glass panel  110 . In another embodiment, shown in  FIG. 9C , the wiper-type coolant deflector  215   a  may be provided on the top and bottom sides of the glass panel  110  or one wiper-type coolant deflector  215   a  may be provided on only the bottom side of the glass panel  110 . 
       FIG. 9  also shows that the coolant guard  125   a  is positioned such that it extends substantially perpendicular to the plane of the glass panel  110 . In another embodiment shown in  FIG. 9D , the coolant guard  125   d  is positioned such that it tilts toward the conveyor belts  105 ,  106 . In a third embodiment, shown in  FIG. 9E , the coolant guard  125   e  is positioned such that it is tilted away from the conveyor belts  105 ,  106  and reaches over the grinder wheels  120 . 
       FIG. 10  shows a side perspective of a coolant guard  125   f  and wiper-type coolant deflector  215   d  according to another embodiment. In this embodiment, the coolant guard  125   f  does not include the channel  135   a , and the wiper-type coolant deflector  215   d  is affixed to a bottom landing  126   f  of the coolant guard  125   f . The wiper-type coolant deflector  215   d  is also configured differently to allow it to be affixed by a fastener  225   d  inserted through a slot in the bottom landing  126   f  and into the wiper-type coolant deflector  215   d . The wiper-type coolant deflector  215   d  is made of a sturdy upper threaded element  218   d  that will hold the wiper-type coolant deflector  215   d  in place and a lower wiper element  219   d  that is configured to ride along the glass panel  110  and prevent coolant from flowing over the glass surface  110 . 
     In one embodiment, to allow the wiper-type coolant deflector  215   d  to be positioned as close to the grinder wheel  120  as possible to protect more of the glass panel  110  surface, the coolant guard  125   f  may be provided as an angled portion  127   f.    
     As is shown in  FIG. 11  from a top perspective view of the coolant guard  125   f  of  FIG. 10  from the conveyor side, the bottom landing  126   f  of the coolant guard  125   f  may be provided with a slot  230   d  to correspond to each fastener  225   d . This allows an operator to adjust the distance between the edge of the glass panel and grinder wheel  120  as desired. 
     As is shown in the top perspective view of  FIG. 12 , fender-type coolant deflectors  115   d  and wiper-type coolant deflectors  215   e  may be both utilized to reduce coolant and abrasive particle ingress. In this embodiment, the fender-type coolant deflectors  115   d  are provided with two brackets  195   a ,  196   a , which can be mounted to the top surface and side of the bottom plate  133  of the wheel box  130  of  FIG. 2 . As can be seen in  FIG. 12 , the brackets  195   a ,  196   a  may be provided with slots that permit the fender-type coolant deflectors  115   d  to be adjusted vertically or horizontally. The fender-type coolant deflectors  115   d  may also be welded or otherwise mechanically attached to the coolant guard  125   g.    
     In the embodiment shown in  FIG. 12 , the channel  135   a  discussed above is omitted. In this embodiment, a wiper-type coolant deflector  215   e  is provided. The coolant guard  125   g  is bent in at a 90° angle to create a bottom landing  126   g  and define a clearance between the glass panel being ground and the coolant guard  125   g . The wiper-type coolant deflector  215   e  may be affixed to the coolant guard  125   g  in any of the manners discussed above. A bracket  155  is also provided to couple the coolant guard  125   g  to the wheel box  130  of  FIG. 1 . 
     In another embodiment, shown in  FIG. 13 , the coolant guard  125   h  of the grinder assembly  100  may be provided with both a fender-type coolant deflector  115   e  and a wiper-type coolant deflector  215   f  to reduce coolant ingress. In another embodiment, shown in  FIG. 14 , the wiper-type coolant deflector  215   g  may also be affixed adjacent to the notch  140   e  on the top and bottom of the glass plate  110  to increase the effectiveness of the fender-type coolant deflector  115   f . In this embodiment, the wiper-type coolant deflector  215   g  is segmented and each segment is curved as shown in order to reduce coolant ingress through the notch  140   e  shown in  FIG. 13 . The lower coolant guard, shown in  FIG. 9C , is omitted in  FIG. 14 . 
     While various embodiments have been described herein, various modifications and changes can be made. Accordingly, the disclosed embodiments are not to be considered as limiting as the invention is defined solely by the scope of the appended claims.