Abstract:
An apparatus and method for shirring netting onto a netting tube. A second tube is placed over and coaxially to the netting tube and netting is stretched over the second tube. The two tubes are caused to move in a reciprocating manner through a plurality of spring-loaded fingers, which allow the netting to pass on the downstroke and hold the netting on the upstroke. As the two tubes move, the netting is pulled over the second tube and shirred onto the netting tube. An annular space formed by a tube ring placed between the netting tube and the second tube causes the netting to shir in multiple, neatly aligned layers.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates to the field of preparing food products in shirred, tubular casings and enclosing the products in a netting. One method generally used in the industry is to pump food products, such as sausage meat, whole muscle meats, or otherwise, through a product horn. The meat products are forced into an edible film and then into netting. The food products to be packaged will expand and push the film through the netting. After processing, such as smoking or cooking, the netting will be removed, leaving a dimpled appearance on the food products that is considered pleasing to consumers. The edible casing will prevent the netting from sticking to the meat, so upon removal of the netting a clean appearance of the meat is maintained. (There is no reason why the invention is limited to meat; it can be used for cheese or vegetarian sausage or anything else for which a dimpled appearance is desired.) This method is illustrated in U.S. Pat. No. 4,910,034 and its divisional, U.S. Pat. No. 4,958,477. As can be seen from FIG. 4 of those two patents, there are three coaxial tubes. The sausage meat or other ingredient is pumped into the smallest diameter tube; the middle tube forms the edible casing into a tube; and the outer tube (the “netting tube”) holds the netting. 
   The netting used in this process arrives from the manufacturers in a flattened state and wrapped circumferentially on a disposable cylinder. In order to be used as described above, the netting has to be shirred onto a temporary netting tube. This shirring process, or “rucking”, involves placing the netting coaxially onto the netting tube. There is an advantage to being able to maximize the amount of netting placed on the netting tube, in that minimizing downtime to change netting tubes causes disruptions and inefficiencies in the process. Once the netting has been shirred onto the netting tube, the tube is place on a sausage making machine for extrusion of sausage, as described in U.S. Pat. Nos. 4,910,034 and 4,958,477 and as illustrated in, for example,  FIG. 7  of those patents. 
   In the prior art, a netting tube is caused to reciprocate vertically, such as by use of an air cylinder. The netting is stretched over the tube. A plurality of spring-loaded fingers secured to a bracket surround the netting tube circumferentially. These fingers are normally in a horizontal position. Downward force moves them down; the springs cause them to snap back to the normal horizontal position when the force is removed. Accordingly, the fingers carry the netting downward during the upward stroke of the tube, and slide over the netting during the downward stroke of the tube. The reciprocating motion of the netting tube therefore causes the netting to be shirred onto the netting tube. This prior art is described in, for example, U.S. Pat. No. 5,273,481. Note that only one layer of netting is shirred onto the netting tube by this method. 
   A prior art improvement is to add a second tube, which fits coaxially over the netting tube. The netting is stretched over the second tube. As the netting is carried over the second tube, the second tube rises in relation to the netting tube and the netting is shirred onto the netting tube, in the space between the base of the netting tube and the now-rising second tube. More netting can be shirred onto the netting tube in this manner, as compared to the prior art method of the previous paragraph, because multiple layers can be shirred, thereby rucking more linear feet of netting per length of netting tube. However, the netting is not shirred particularly neatly by this method. It bunches up and is wavy. The generally unkempt appearance of the netting on the tube is displeasing to prospective purchasers of the equipment. Additionally, and more importantly, the lack of neatness, caused as it is by a lack of uniformity, prevents shirring as much netting onto the tube as may be hoped for. 
   This prior art improvement used a second tube with a larger inside diameter than the outside diameter of the netting tube. Accordingly, a tube cap is inserted into the top of the second tube, to keep the second tube moving coaxially to the netting tube, and to allow the netting to slide smoothly over the second tube. A coaxial ring in the bottom of the second tube keeps the second tube coaxial to the netting tube, and will push the netting downward on the netting tube. 
   Although this prior art improvement increases the amount of netting that can be rucked onto a netting tube, further increases in this amount are desirable to users of the apparatus. Additionally, newly-developed devices attach to the output end of the netting tube during sausage making and allow the netting to slide off the netting tube in discrete, predetermined lengths. These newly-developed net deruckers require a clear space on the end of the netting tube, a space greater than the length of sausages to be made, further limiting the amount of netting that can be rucked onto the netting tube. Accordingly, the use of a net derucker further increases the need for maximizing the amount of netting that can be rucked onto a netting tube of given length. (Please note that more netting can be rucked onto a netting tube simply by increasing the size of the netting tube, but this option is not available or, at best, is impractical, for users with limited space.) 
   Accordingly, it is an object of the present invention to increase the amount of netting that can be rucked onto a netting tube. It is a further object of the present invention allow more netting to be rucked onto the netting tube and leaving a large length of netting tube without rucked netting, to allow for the use of a net derucker. It is a further object of the present invention to cause the netting to ruck neatly onto the netting tube. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention is an improvement to the prior art comprising placing a coaxial ring between the netting tube and the second tube, a distance from the bottom end of the second tube, creating an annular space defined by the netting tube, the ring, and the second tube. The netting curls underneath the second tube and fills this annular space first. On the next stroke, netting is shirred over the netting that had been shirred into this annular space. This method causes the netting to be shirred neatly, in multiple layers, without waviness, and allows more netting to be shirred onto a given length of netting tube. 

   
     BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is an elevational view of the apparatus of the present invention, without any netting in place. 
       FIG. 1A  is the same elevational view as  FIG. 1 , with the netting shown. 
       FIG. 2  is a perspective view of the netting tube. 
       FIG. 3  is an elevational view of the tube cap ring. 
       FIG. 4  is a perspective view of the preferred embodiment of the second tube. 
       FIG. 5  is a plan view of the lower tube ring. 
       FIG. 6  is an elevational view of the preferred embodiment of the second tube placed over the netting tube. 
       FIG. 7  is a partial cutaway elevational view of the preferred embodiment of the second tube. 
       FIG. 8  is a partial cutaway elevational view of the preferred embodiment of the second tube placed over the netting tube. 
       FIG. 9  is a partial cutaway elevational view of another embodiment of the second tube placed over the netting tube. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The organization and manner of the preferred embodiments of the invention, together with further objects and advantages thereof, may best be understood by reference to the following description of the preferred embodiment of the invention, taken in connection with the following drawings: 
   The preferred embodiment of the net rucking apparatus  2 , is shown in elevation view in  FIG. 1  without the netting  4  present, and in  FIG. 1A  with the netting  4  present. The apparatus  2  comprises a frame  10 , a netting tube  40 , and a second tube  50 . The frame  10  has legs  12  to support it, and upper arms  14  that hold a net rucker head  16 . The net rucker head  16  defines a passage  18  through which the netting tube  40  and second tube  50  pass. Attached to the net rucker head  16  and extending into the passage  18  are a plurality of spring-loaded fingers  20 . 
   A moveable platform  22  sits on top of the frame  10 . It is configured to travel in an upward and downward direction, powered by lifting means. In the preferred embodiment, the lifting means comprise an air-actuated cylinder  24 , connected to an air supply  26  which is controlled by a control means  28 . Any lifting means that can provide reciprocating axial action will suffice, such as a gear arrangement, another type of hydraulic cylinder, or a treadle. In the preferred embodiment, the control means  28  is a microprocessor with an application specific program written to it, but any suitable controller, digital or analog, will suffice. 
   Netting  4  is placed in a net tray  30  that is attached to an upper arm  14 . The leading edge of the netting  4  travels up to a net guide  32 , attached to and above one of the upper arms  14  and above the net rucker head  16 . The net guide  32  leads the netting  4  down through the passage  18  as will hereinafter be described. 
   The netting tube  40 , shown enlarged in  FIG. 2 , is a hollow cylinder with a base plate  42 . In the preferred embodiment, the netting tube  40  is stainless steel, for use in a food-processing environment. There are attachment means  44  on the baseplate, to hold the netting tube  40  securely to the moveable platform  22 . The attachment means  44  are preferably identical to the means by which the netting tube will be attached to a sausage-making machine after rucking of the netting  4 . The attachment means  44  can be a simple nut-and-bolt arrangement, a locking clamp, or any system to hold the netting tube  40  firmly to the moveable platform  22 . 
   The second tube  50 , shown in perspective view in  FIG. 4 , is also a hollow cylinder, with an inside diameter greater than the outside diameter of the netting tube  40 . The second tube  50  is preferably made of a heavy plastic, to allow netting  4  to slide over it easily. At the top of the second tube  50  is placed a tube cap ring  52 , shown in elevational view in  FIG. 3 . The tube cap ring  52  is a toroidal element with a notched edge  53 , so that it has one outer diameter equal to the outer diameter of the second tube  50 , and a second outer diameter equal to the inner diameter of the second tube  50 , allowing the tube cap ring  52  to snap onto the top end of the second tube  50 . The tube cap ring  52  has an inner diameter just slightly larger than the outer diameter of the netting tube  40 , so that the tube cap ring  52  can slide easily axially to the netting tube  40 . The tube cap ring  52  is rounded or at least angled on the side opposite the notched edge, to allow netting  4  to slide over it easily, as the purpose of the tube cap ring  52  is to prevent snagging. In the preferred embodiment, the tube cap ring  52  stays firmly attached to the second tube  50  by an interference fit, but glue could also be used if necessary. 
   A lower tube ring  54 , shown in plan view in  FIG. 5 , is also of a toroidal shape and is placed inside and coaxially to the second tube  50 . The lower tube ring  54  has an outer diameter equal to the inner diameter of the second tube  50  and forming an interference fit, so that the lower tube ring  54  stays firmly situated inside the second tube  50 . The inner diameter of the lower tub ring  54  is, like the tube cap ring  52 , just slightly larger than the outer diameter of the netting tube  40 , so that the lower tube ring  54  can easily slide axially to the netting tube  40 , as shown in elevation view in  FIG. 6 . The lower tube ring  54  is placed inside the second tube  50 , a short distance, preferably an inch, from the bottom of the second tube, as shown in partial cutaway view in  FIG. 7 . Because the lower tube ring  54  is placed a short distance from the bottom end of the second tube  50 , an annular space  56  is defined by the netting tube  40 , lower tube ring  54 , and the second tube  50 . When the tube cap ring  52  and the lower tube ring  54  are put in place on the second tube  50 , as shown in elevation view on  FIG. 6 , the tube cap ring  52  and the lower tube ring  54  slide easily along the netting tube  40 , so that the second tube  50  travels coaxially to the netting tube  40 . In an alternative embodiment, extra lower tube rings  54  can be placed inside the second tube  50 . Only the lower tube ring  54  that defines the annular space  56  is necessary for this present invention, however. 
   In another embodiment, the second tube  50  has an inner diameter just slightly greater than the outer diameter of the netting tube  40 , as shown in  FIG. 9 . Instead of placing a lower tube ring  54  in the bore of the second tube  50 , however, a notch  58  is cut out of the lower end of the second tube  50 , thereby forming the annular space  56 . 
   For use, the netting tube  40  is placed on the moveable platform  22  and attached by the attachment means  44 . The second tube  50 , with its two rings  52 ,  54  in place, is placed over the netting tube  40 . The moveable platform  22 , by its reciprocating motion, causes the netting tube  40 , surrounded by the second tube  50 , to travel in a reciprocating, coaxial movement through the passage  18 . 
   The spring-loaded fingers  20  are arranged so that they conform to the diameter of the second tube  50  and the netting tube  40 . During downward travel of the second tube  50  and the netting tube  40 , the fingers  20  are pushed away circumferentially from the two tubes  40  and  50 , allowing netting  4  to travel in a downward direction. When the second tube  50  and netting tube  40  travel upward, the spring-loaded fingers  20  snap back to engage the netting and prevent it from traveling. 
   Accordingly, in use the netting  4  is placed in the net tray  30  and the free end is run through the net guide  32  and over the second tube  50 , to at least a point below the reciprocating fingers  20 . As the moveable platform  22  moves down, it pulls netting  4  down with it, past the spring-loaded fingers  20 . When the reciprocating platform  22  reaches the bottom of its downstroke, the cylinder  24  reverses movement to an upward direction, pushing the netting tube  40  and second tube  50  through the passage  18 . The spring-loaded fingers  20  now engage the netting  4  on the second tube  50  and prevent it from traveling. The second tube  50  nevertheless continues in an upward path, as the netting  4  can slide over the smooth plastic surface of the second tube  50 , so the netting  4  moves downward relative to the second tube  50 . Thus, as the moveable platform  22  reverses again in its reciprocating motion, the netting  4  is pulled down toward the bottom of the second tube  50 . When the netting gets to the bottom of the second tube  50 , the spring-loaded fingers  20  push it off the second tube  50  and the netting  4  contracts around the smaller-diameter netting tube  40 . Accordingly, the second tube  50  is forced slightly upward, relative to the netting tube  40 , by the spring-loaded fingers  20 , as netting  4  is rucked onto the bottom of the netting tube  40 . On each upward stroke of the moveable platform  22 , more netting  4  is pushed by the spring-loaded fingers  20  off the second tube  50  and onto the netting tube  40 . The spring-loaded fingers  20  push the netting  4  inward, causing it to fill the annular space  56 . Because of the annular space  56 , the netting  4  is rucked neatly and several layers thick. Accordingly, the apparatus  2  will ruck approximately four to five times as much netting  4  onto a given size of netting tube  40  as a conventional rucker without this annular space. 
   While preferred embodiments of the present invention are shown and described, it is envisioned that those skilled in the art may device modifications of the present invention without departing from the spirit and scope of the appended claims.