Abstract:
An improved end seal for a sheeting apparatus. A sealing material is formed into a more effective sealing element which locks out doughy material out of associated side sealing parts near the sheeting nip. Such an improved end seal provides improved wiping and sealing functions. Such a seal also reduces wear thus reducing the frequency of seal replacement. Such a seal reduces the amount of installation time and amount of error associated with manual adjustment ordinarily required to replace end seals.

Description:
BACKGROUND  
       [0001]     1. Technical Field  
         [0002]     The present invention relates to an improved apparatus to seal the sides of the nip area at the sides of opposing sheeter rollers generally mounted parallel to each other. An improved seal prevents doughy material from penetrating into crevices of the apparatus according to the prior art as doughy material is compressed into a sheet. Specifically, this invention uses improved materials and configurations to create a new side seal for a sheeting apparatus.  
         [0003]     2. Description of Related Art  
         [0004]     With reference to  FIG. 1 , in a conventional dough sheeter, opposing rollers  110  are separated by a small gap or nip  102 . Doughy material  104  is fed into the nip  102  above opposing rollers  110  and passes through the nip  102  to form a sheet  106 . It is normally necessary to place a seal at the ends of opposing sheeter rollers to prevent leakage of doughy material from the sides of opposing rollers  110 . Leakage results in loss of valuable product as well as thinning of the dough sheet near the edges.  
         [0005]      FIG. 2  shows an overhead view of conventional side seals. With reference to  FIG. 2 , side seals  210  are typically made of a plastic or other low-friction material, and are pressed against the ends of sheeting rollers  110  by mechanical means including, but not limited to, screws  204  attached to a sheeter housing  206 . Such side seals  210  press with a force greater than the pressure created by the sheeting process. There are several drawbacks to conventional arrangements including seal leakage, seal wear due to pressurized contact, and poor accessibility for seal replacement.  
         [0006]      FIG. 3   a  is a cross-sectional drawing of a portion of a prior art side seal. Such a side seal according to the prior art consists of a side seal bracket  320  of arbitrary shape made of metal or other stiff material, a shim  312  also made of a metal or other stiff material, and a plastic sealing piece  308 .  FIG. 3   a  shows such a portion of a side seal after newly assembled and before operation of a sheeting apparatus. The shim  312  is held in place by one or more screws  314 .  
         [0007]     Often, manual adjustment of the side seal is required to obtain the desired distance between the plastic sealing piece  308  and the sheeting rollers  512 ,  514 . Generally, the shims  312  and screws  314  must be manually adjusted to bring the sealing pieces  308  within about 0.05 inches (1.27 mm) to 0.07 inches (1.78 mm) of the side surface of the sheeting rollers  512 ,  514  along the length of the sealing piece  308 . According to some embodiments of the prior art, such adjustment may require up to twelve hours of manual adjustment each time the seals are replaced. According to the prior art, side seals wear out within about one month of continuous sheeting operation.  
         [0008]     With reference to  FIG. 3   a,  when the side seal is assembled, the shim  312  and plastic sealing piece  308  are tightly abutted to each other, and the plastic sealing piece  308  is uniform having no wear.  FIG. 3   b  is a similar cross-sectional drawing showing the same pieces of a side seal after having been subjected to approximately one month of continuous operation and wear. Over time, doughy material  104  is forced into the interface between the plastic sealing piece  308  and the metal shim  312  by the operating or sheeting pressure generated by opposing sheeting rollers  512 ,  514 . As seen in  FIG. 3   b,  repeated penetration of doughy material  104  between the sealing piece  308  and the metal shim  312  has forced the plastic sealing piece  308  to bulge outward toward the sheeting rollers  110 . This has caused the plastic sealing piece  308  to wear away and to be replaced by doughy material  104  although still maintaining a relatively flat outer surface  402 . Over time, the thickness of the plastic sealing piece  308  remains thicker near the attaching screw  310 . If the plastic sealing piece  308  is not replaced, the side seal eventually becomes ineffective.  
         [0009]     Consequently, a need exists for an improved apparatus to provide for more effective sealing of the sides of a dough sheeter and less waste of doughy material. A need exists to eliminate the required manual adjustment necessary to replace plastic sealing pieces. A need exists for an apparatus that allows for easier, faster installation of replacement side sealing pieces. A further need exists to eliminate plastic sealing material from entering sheeted dough as the plastic sealing piece is worn away during sheeting operation. Additionally, a need exists to reduce the frequency of replacing worn plastic sealing pieces.  
       SUMMARY OF THE INVENTION  
       [0010]     The proposed invention comprises an improved end seal for a sheeting apparatus. A sealing material is formed into a more effective surface to prevent doughy material from leaving the sheeting nip. In one embodiment, an improved end seal provides an improved wiping and sealing function. Such an improved seal also reduces wear by preventing doughy material from being forced into the seal assembly, thus reducing the frequency of seal replacement. Such an improved seal reduces the amount of installation time and amount of error associated with manual adjustment ordinarily required to replace end seals. Additional features and benefits of the present invention will become apparent in the following written detailed description.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein:  
         [0012]      FIG. 1  is a drawing showing a cross-sectional side view of a pair of opposing sheeting rollers;  
         [0013]      FIG. 2  is a drawing showing an overhead cross-sectional view of a sheeting apparatus according to the prior art wherein side seals are mounted to the sheeter housing;  
         [0014]      FIG. 3   a  is a drawing of a cross-sectional view of a portion of a freshly installed side seal, and  FIG. 3   b  illustrates a typical side seal after substantial wear and approximately one month of continuous operation;  
         [0015]      FIG. 4  is a partial cross-sectional view of a preferred embodiment of a roller-mounted side seal according to the present invention;  
         [0016]      FIG. 5  is a drawing of one roller and one section of a roller-mounted side seal according to the present invention as seen from the side of a sheeting apparatus; and  
         [0017]      FIG. 5   a  is a drawing showing a close-up view of a bracket used to mount a side seal on the roller shown in  FIG. 5 . 
     
    
     REFERENCE NUMERALS  
       [0000]    
       
           102  nip  
           104  doughy material  
           106  dough sheet  
           110  opposing sheeting rollers  
           204  screws  
           206  sheeter housing  
           210  side seals  
           306  bracket mounting screw  
           308  plastic sealing piece  
           310  seal attaching screw  
           312  shim  
           314  set screw  
           316  seal distance  
           320  side seal bracket  
           402  flat outer surface in  FIG. 3   b,  mating contour in  FIG. 4   
           400  sealing element  
           402  mating contour  
           404  roller lip  
           406  groove  
           408  back surface  
           410  bracket lip  
           512  first sheeting roller according to a prior art apparatus  
           514  opposing sheeting roller according to a prior art apparatus  
           500  improved sealing bracket  
           502  seal mounting hole  
           504  bracket mounting hole  
           612  first sheeting roller  
           614  opposing sheeting roller  
       
     
       DETAILED DESCRIPTION  
       [0046]     While the invention is described below with respect to a preferred embodiment, other embodiments are possible. The concepts disclosed herein apply to other systems for producing sheeted products.  
         [0047]     The primary objective of this invention is to provide an apparatus which provides improved sealing of the sides of the nip area of a dough sheeting apparatus. In one embodiment, a side seal is made such that after it is mounted in place, the side seal lightly or nearly contacts the side edge of the sheeting rollers. In such an embodiment, no shim  312  is required. One or more shims, however, may be used, depending on the specific application. One or more plastic sealing pieces are attached to a bracket by screws or other mechanical means. Such a side seal is mounted to a housing or other member adjacent to the nip region of the sheeting rollers.  
         [0048]     With reference to  FIG. 4 , according to a preferred embodiment of the invention, side seals are mounted on the sides of a first sheeting roller  612 , across the sheeter nip  102 , and overlap an opposing sheeting roller  614 . With reference to  FIG. 4 ,  FIG. 5 , and  FIG. 5   a,  a sealing element  400  is attached with attaching screws  310  through seal mounting holes  502  to an improved sealing bracket  500 . An improved sealing bracket  500  has a bracket lip  410  on the edge of a sealing bracket  500  which tightly holds a sealing element  400  in place. In one embodiment, a sealing element  400  is formed with a mating contour  402  that coordinates with a bracket lip  410  along the edge of a sealing bracket  500 , which contributes to maintaining tightly in place the sealing element  400 . A bracket lip  410  on an improved sealing bracket  500  holds a sealing element  400  along the entire circumference of a sheeter roller and is not held solely by mounting screws  310 . Such an arrangement of pieces reduces wear to a seal element  400  by reducing the possibility that dough is forced into the seal assembly such that replacement of a seal element  400  is only necessary about every few years instead of about once per month. In another embodiment, screws  310  are not used to attach a sealing element  400  because of the presence of a bracket lip  410  of an improved sealing bracket  500 .  
         [0049]     In another embodiment, an improved sealing bracket  500  or sealing element  400  is formed such that there is no need for a shim  312  along the back surface  408  of the sealing element  400 . Such sealing element  400  eliminates a necessity in the prior art to manually adjust the distance  316  between a sealing piece  308  and the side surface of an opposing sheeting roller  614  by the addition of one or more shims  312 . With fewer pieces, replacement of side seals takes less time translating into more time of actual sheeter operation. In one embodiment, replacement of side seals takes about two hours.  
         [0050]     In another embodiment, a sealing element  400  is formed such that when the sealing element  400  and the improved sealing bracket  500  are installed, the distance  316  between the sealing element  400  and the side of an opposing roller  614  is from about 0.05 inches (1.27 mm) to 0.07 inches (1.78 mm). As a reference, the size of the sheeter nip  102  during operation is typically in the range from about 0.008 inches (0.20 mm) to 0.012 inches (0.30 mm). Other sizes of sheeter nip  102  are possible, and other distances between the sealing element  400  and the side of an opposing roller  614  are possible.  
         [0051]     In one embodiment, a sealing element  400  is made of an elastomeric material. Alternatively, a sealing element is made of Delrin®, or Teflon®, two commercially available materials. In another embodiment, a sealing element is made of ultra high molecular weight polyethylene (UHMWP). UHMWP has long molecular chains, is durable and versatile, and is used in many industries. UHMWP, Delrin®, Teflon®, and elastomeric materials have desirable attributes such as a high abrasion resistance, a low coefficient of friction, and unparalleled impact resistance.  
         [0052]     In one embodiment, a sealing element  400  is formed such that it fits in an improved sealing bracket  500  and fits tightly against the most proximal portion of a side surface of a first sheeting roller  612 . The side surface may form part of a roller lip  404 . A sealing element  400  is preferably formed with a groove  406  such that the sealing element  400  is held tightly around a roller lip  404  of the first sheeting roller  612 . This improvement avoids gaps and crevices between a plastic sealing piece  308 , any shims  312 , and a first sheeting roller  612 . Such improvement prevents doughy material  104  from being forced into such areas while the doughy material  104  is under operating sheeting pressure.  
         [0053]     In one embodiment, a sealing element  400  is pressed firmly against the side of a first sheeting roller  612  by a screw  306 . In other embodiments of the invention, other types of fasteners may be used. Doughy material under sheeting pressure is thereby further prevented from infiltrating crevices between attached parts. With such improved features, a sealing element  400  more effectively performs wiping and sealing functions along the sides of an opposing sheeting roller  614  during the operation of the sheeting apparatus.  
         [0054]     With reference to  FIG. 5  and  FIG. 5   a , side seals are mounted piecewise around the circumference of a first sheeting roller  612 . In one embodiment, twelve pieces or sealing brackets  500  are used to apply a complete side seal which covers the entire circumference of one side of a sheeting roller  612 . A side seal can be joined to each side of the first sheeting roller  612 , and thus the sheeter nip  102  can be sealed on both sides. In  FIG. 5   a,  each improved side seal bracket  500  is attached to a first sheeting roller  612  by screws (not shown) placed in bracket mounting holes  504  along one side of an improved side seal bracket  500 .  
         [0055]     While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.