Abstract:
A clipping device is provided for closing stuffed food casing with a clip and an apparatus is provided for causing a taped, holding string loops, to be directed toward the clipping device for closing an end of the food casing so that a string loop is transferred directly from the tape into an entry into a channel in the clipping device. The clip draws the loop to the casing and holds the loop to the food casing. The stuffing apparatus preferably also includes a novel readily cleanable food flow cut-off valve. A punch and clip anvil is provided to apply clips bent around the casing in essentially mirror image helixes. An extending and retracting conveyor is provided to remove stuffed food product from the vicinity of the clipping device after stuffed food casing is closed.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates to apparatus for automatically stuffing tubular food casing with food product, especially meat type products such as sausage meat. 
   There have been a number of problems associated with known food casing stuffing machines. In particular, there has been no reliable way to automatically attach hanging loops, especially string loops, to the end of a stuffed food casing product. It has been difficult to control the flow of meat through the stuffing horn so that flow reliably starts and stops so that the flow properly fills the casing and so that food product does not continue to leave the stuffing horn after the desired section of food casing is filled. Further, it has been difficult to clean devices that control the flow of food product. There has further been a problem with existing apparatus for stuffing tubular food casings with respect to speed of processing. Cycle times for automatically stuffing food casing have not been as fast as desired. Another problem associated with existing apparatus for stuffing and closing tubular food casings has been a tendency for some clips to improperly bend around an end of a stuffed food casing link, e.g. a sausage link, to properly close the casing without leakage, injury to the casing, process interruption or sharp points extending from the closure. A further problem has been that conveyors for moving stuffed food casing product from a closure area have not been sufficiently adaptable to handle various lengths of food casing links, including slack filled links and that to the extent that such conveyors were adaptable, they sometimes extended and retracted relative to the frame of the apparatus thus creating a striking hazard to personnel in the area of the conveyor when it extended. 
   It is therefore an object of the invention to eliminate or ameliorate the problems as above described in addition to other problems subsequently described. 
   BRIEF DESCRIPTION OF THE INVENTION 
   In accordance with the invention an apparatus is provided for automatically stuffing tubular food casing with food product. The apparatus, in a preferred embodiment includes a stuffing horn through which food product flows into tubular food casing which is deshirred from a shirred food casing stick on the stuffing horn. An input end of the stuffing horn is interconnected with a pressurized source of food product. Preferably, a clipping device is provided for closing stuffed food casing with a clip and apparatus is provided for causing a tape, holding lengths of string having end portions secured together to form string loops, to be directed toward the clipping device for closing an end of the food casing so that a string loop is transferred directly from the tape into an entry into a channel in the clipping device so that when the end of the food casing is closed with the clip, the clip draws the loop to the casing and holds the loop to the food casing between a major portion of the loop and the secured together end portions of the string. The apparatus for causing the tape to be directed toward the clipping device includes a plurality of rolls. At a minimum, the rolls usually include a tape supply roll, a takeup roll and at least one intermediate roll which is proximate the entry to the channel so that the secured together end portions of a string project from the tape into the entry into the channel as the tape passes around the intermediate roll. 
   The apparatus includes a drive section for driving the takeup roll to pull the tape from the supply roll around the intermediate roll and an edge is provided for releasing secured together end portions of a string loop as it passes around the intermediate roll to cause the secured together portions of the string to protrude from the tape into the entry to the channel and to assist in removal of the string loop from the tape. Preferably an air source is further provided that directs the secured together end portions of the string loop into the entry to the channel. Desirably, the secured together portions of the string are secured together by a knot. 
   The apparatus includes a stuffing horn through which food product flows into tubular food casing deshirred from a shirred food casing stick on the stuffing horn, an input end of the stuffing horn being interconnected with a pressurized source of food product through a food product cut-off apparatus. The cut-off apparatus preferably includes a valve that has a tapered valve seat having a frustoconical tapered side wall and having opposing inlet and outlet openings in the side wall. The valve further has a frustoconical plastic insert tapered to mate with the tapered valve seat for insertion into the valve seat. The plastic insert has a longitudinal axis and a hole passing through the insert perpendicularly to the longitudinal axis in a position such that it may be rotated to cause the hole to align with the opposing inlet and outlet openings in the side wall of the valve seat to permit food product to pass through the inlet opening in the valve seat, through the hole in the insert and through the outlet opening in the valve seat to the stuffing horn. The insert may also be rotated to cause the hole to become misaligned with the inlet and outlet openings to impede the flow of food product to the stuffing horn. 
   Apparatus, including two sets of gatherer arms, is provided to radially compress the stuffed food casing to cause a restricted location along a stuffed food casing length and the clipping device is configured to clip the casing at the restricted location. The clipping device is preferably of sufficiently light weight and is driven by a sufficient power source to obtain a clipping cycle time of less than 3 seconds for fully filled casing and less than 5 seconds for slack filled products. 
   A clip anvil is preferably provided that permits spaced clips to be simultaneously applied to the casing at the restricted location so that the clips are bent around the casing in essentially mirror image helixes. 
   A conveyor is desirably provided to remove stuffed food product from the vicinity of the clipping device after stuffed food casing is closed. The conveyor includes a conveying belt that travels over slacker idler rollers beneath a conveying surface of the belt. The slacker idler rollers permit the length of the conveying surface to be extended and retracted to extend and reduce a space between the clipping device and the conveying surface so that the gatherer arms and clipping device can operate free from obstruction by the conveyor. 
   Apparatus, including at least one conveyor drive cylinder, is provided to cause the conveyor to retract to increase the space when gatherers for the clipping device are operating to gather stuffed food casing to form a radial restriction in the stuffed food casing and to extend to reduce the space and place the conveying surface near the clipping device when the gatherers are dormant. The stroke of the apparatus, for increasing and decreasing the space, is adjustable to permit distance between sets of gathering arms to be increased and decreased thus permitting an unstuffed length of casing between the closed sets of gathering arms to be withdrawn from the stuffing horn to allow for slack filled (incompletely filled) casing. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an elevational side view of a preferred embodiment of the stuffing apparatus of the invention showing a stuffed food casing link behind which gathering arms have restricted the casing. 
       FIG. 2  shows a side elevational view of the apparatus of  FIG. 1  in a position where gathering arms have been separated and clips are being applied by the clipping device between the gathering arms. The view further shows food casing being withdrawn from the stuffing horn and a tape containing string loops being directed to the clipping device. 
       FIG. 3  shows a side elevational view of the apparatus of  FIG. 1  in a position where gathering arms have been separated by a larger distance that in the position of FIG.  2  and clips are being applied by the clipping device between the gathering arms to provide a length of unfilled casing to provide a “slack filled” product. The view further shows food casing being withdrawn from the stuffing horn and a tape containing string loops being directed to the clipping device. 
       FIG. 4  shows a side elevational view of the apparatus of  FIG. 1  in a position where gathering arms have opened, the clipper has been withdrawn and a new length of casing is being stuffed. 
       FIG. 5  is a magnified view of the tape containing string loops and the clipping device shown in FIG.  1 . 
       FIG. 6  shows a section of a tape containing string loops. 
       FIG. 7  is a detail view of the knife cutting clipped casing to release a filled chub and shows punches above applied clips. 
       FIG. 8  shows a cross sectional top view of the sets of gathering arms, clipping device, anvil, applied string loop and mirror image applied clips. 
       FIG. 9  shows a cross sectional view of a food product cut-off valve of the invention in closed position. 
       FIG. 10  shows a cross sectional view of a food product cut-off valve of the invention in open position. 
       FIG. 11  is an end cross sectional view showing the gathering device with open gathering arms and clipper. 
       FIG. 12  is an end cross sectional view showing the gathering device with closed gathering arms and clipper. 
       FIG. 13  is an end cross sectional view showing the gathering device with closed gathering arms and clipper moved to clipping position. 
       FIG. 14  is an end cross sectional view showing the gathering device with opening gathering arms and clipper moved away from clipping position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   “Automatically stuffing” as used herein means the stuffing of food casing utilizing machine components and electronic and pneumatic controls, essentially without manual intervention, except for loading food casing onto a stuffing horn, loading food product into a storage area for feeding a food product pump, loading clips into a clipper and loading reels of tape containing string loops. It is understood that manual correction of problems slowing down or stopping stuffing operation is permitted. 
   “Food casing” means a tubular food casing of film material including reinforced (fibrous) or unreinforced precipitated or regenerated cellulose in the form of seamless or seamed tubes. Tubular casings extruded from other materials, e.g. collagen and extruded synthetic plastics are also contemplated. The preferred tubular material is fiber reinforced cellulose. 
   “Food product” includes essentially any food product that can be stuffed in a food casing, e.g. sausage meat, ham, turkey and cheese. The preferred food product is a pumpable food product. 
   “Shirred” means a tubular food casing compressed along its longitudinal axis while forming folds in the casing that are radial or helical to aid axial compression. A “shirred stick” means a length of shirred casing that has a hollow axial passage through its center to allow it to be placed over a stuffing horn. 
   The invention may be more readily understood by reference to the drawings which illustrate a preferred embodiment. It is to be understood that the preferred embodiment is intended to illustrate and not limit the invention. Embodiments not illustrated in the drawings are not intended to be excluded. For example, any reasonable frame or support structure can be used such as a supporting box structure. Similarly, cutting devices other than a knife, such as a laser or water jet may be used and orientations may be changed. Any means for moving support such as ball bearings, roller bearings, bushings, or wheels may be used. Further, any suitable drive mechanisms, such as pneumatic cylinders, motors of any kind, chains and sprockets, belts and pulleys and gears are contemplated. 
     FIG. 1  shows a preferred embodiment of an apparatus  10  of the invention for automatically stuffing a tubular casing  12  with food product. The apparatus includes a stuffing horn  16  through which food product  14  flows into tubular food casing  12  deshirred from a shirred food casing stick  18  on stuffing horn  16 . An input end  20  of stuffing horn  16  is interconnected with a pressurized source  22  of food product  14 . 
   The stuffing horn  16  used in the apparatus  10  of the invention is a tube over which is placed a shirred casing  18  and through which food product  14  flows to fill the casing  12 . The stuffing horn  16  may be made of any suitable material but usually is stainless steel or food compatible plastic, as are essentially all parts that come in contact with food product  14 . 
   The pressurized source  22  of food product  14  usually includes a food product pump  22  connected between a food product reservoir and a conduit in the form of a stainless steel or food compatible plastic tube, pipe or other conduit to an inlet end  20  of the stuffing horn  16 . The food product pump  22  is usually a piston type pump that injects food product  14  through the stuffing horn  16  into the food casing  12 . When the food product is in the form of an emulsion or other flowable food product, a cut-off valve  54  is preferably placed in line between an outlet  55  of the pump  22  and the inlet  20  of the stuffing horn  16 . 
   A clipping device  24  is provided for closing stuffed food casing  12  with a clip  26  (best seen in FIGS.  5  and  8 ). 
   The clipping device  24  acts to apply clips  26  to terminal ends  44  of a stuffed food casing chub  11 . The clips  26  are applied in a manner well known for application of clips such as staples, i.e. a U shaped clip is forced over a gathered end  44  of the casing  12  at a restricted location  72  so that ends of the legs of the clip engage an anvil  78  having a curved guide  79  in its surface such that continued pressure provided by a punch  31  on the clip  26  forces the legs to follow the guide  79  to bend them around the casing  12  in a helical configuration. The clip anvil  78  preferably permits spaced clips to be simultaneously applied to the casing at the restricted location  72  so that the clips  26  are bent around the casing in essentially mirror image helixes. For reasons not completely understood, clips  26  are more reliably and efficiently applied when this configuration is used. 
   The clipping device  24  is configured to rotate into a position such that the punch  31  is above the restricted portion  72  of casing  12  and the anvil  78  is below the restricted portion of the casing to apply one or more clips  26  when needed and to rotate away from the casing  12  when it is not needed. Clips  26 , in the form of a strip  27  where the clips  26  are loosely attached to each other in sequence, are loaded into a magazine  29  such that punch  31  traveling in a guide slot channel  33  engages a single clip  26  at an end of the strip  27  that forces the clip  26  down the channel  33 , disengaging it from the strip  27  to force the clip  26  over the casing  12  as previously described. When the clipping device  24  is not in a position to be used, it is preferably rotated away from a position above the casing  12 . 
   Usually two clips  26  are simultaneously applied using parallel punches  31  or a single punch  31  having dual punch surfaces. After clipping, a knife  51  is moved into position to sever the casing  12  between applied clips  26  to free a finished stuffed chub  11 . 
   The clipping device  24  is provided with at least one slot  48  for receiving secured together (knotted) end portions  32  of a string loop  34  that when the clip  26  moves down the channel  33  it engages the string loop  34  and carries it down a slot  48  to a restriction  72  of the food casing  12  and traps it between the clip  26  and food casing  12  at a location on the loop portion of the string  30  near the secured together portions  32  of the string  30 , usually a knot, so that the string  30  cannot be pulled free without pulling the knot under the clip. The stuffed food casing chub  11  can thus be reliably hung from the string loop  34 . 
   The clipper  24  is made from light materials and strong but light construction design to reduce weight and its movement to the clipping location and movement of the punch  31  is powered by drives of sufficient power to provide a cycle time of from—to—seconds. 
   As best seen in  FIGS. 5 and 6 , a tape  28  is provided that carries string loops  34  formed from string  30  to be transferred to clipping device  24  so that the clip  26  draws the string loop  34  to the casing  12  and holds it there between a major portion  50  of the loop  34  and secured together end portions  32  of string  30 . Tape  28  is provided from a supply roll  36 , around idler rolls  40 , an edge  42 , a drive roll  52 , and a takeup roll  53  to a collection reservoir  55 . As the tape moves around edge  42 , string loops are freed from the tape primarily due to the sharp bending of the tape. As the loops are freed, the secured together end portions  32  enter into slot  48  in the clipping device  24 . The movement of the drive roll  52  is timed so that a loop is released in time to be caught by a clip descending in channel  33  so that it is carried to the casing  12  and trapped between clip  26  and casing  12 . An air source  43  is preferably provided to assist in directing the end portion  32  into the entry  46  of slot  48 . 
   In a preferred embodiment, string loops  34  are supplied on a tape  28  which may be almost any fabric or film but is usually a synthetic or natural film such as polyethylene or regenerated cellulose. The string loops  34  are loosely attached to the tape  28 , usually by means of a release type contact cement. This permits the loops  34  to be stored and transported on the tape  28  yet also permits the loops  34  to be easily removed by pulling the tape  28  around the edge  42 , where the edge  42  either interposes between the string loop  34  and the tape  28  or preferably simply contacts and sharply bends the tape  28  on a surface opposed to the surface on which the string loops  34  are attached to release the loops  34  secured together end portions (knot)  32  first so that the secured together end portions  32  enter the slot  48  in the clipper. 
   As previously discussed, a cut-off valve  54  is preferably provided that is a valve having a tapered valve seat  56  with a frustoconical tapered side wall  58  with opposing inlet and outlet openings  60  and  62  in the sidewall  58  and a frustoconical plastic insert  64  to mate with the tapered valve seat  56 . The plastic insert  64  has a hole  68  passing through the insert  64  essentially perpendicular to its longitudinal axis  66  in a position so that the insert  64  can be rotated about its longitudinal axis  66  to cause the hole  68  to align with the opposing inlet  60  and outlet  62  openings in the sidewall  58  to permit food product  14  to pass through the valve  54  and to permit rotation of the insert  64  to cause misalignment to impede (including completely stop) the flow of food product  14  to the stuffing horn  16 . The tapered sidewall  58  is usually made from a food compatible corrosion resistant metal, e.g. stainless steel, but may also be made from a food compatible plastic, e.g. polyethylene, polypropylene, perfluoroethylene (TEFLON®) or nylon. The insert  64  is usually made from a food compatible plastic as above described. 
   A conveyor  80  is provided for the purpose of removing a finished stuffed and clipped food casing chub  11  from the region of the clipping device  24 . 
   As previously discussed, the conveyor  80  includes a conveying belt  82  that travels over slacker idler rollers  84 ,  86 , and  88  beneath a conveying surface  90  of the belt  82 . The belt  82  is preferably a fabric material such as a woven web of rayon or nylon but may be of other suitable material such as in the form of a flexible rubber or elastomeric sheet or a metal mesh. The slacker idler rollers  84 ,  86  and  88  hold the belt  82  taught and may move to permit the length of the conveying surface  90  to be extended and retracted to extend and reduce a space  92  between the clipping device  24  and the conveying surface  90  so that gatherer arms  96  provided for squeezing the casing to a restriction  72  that can be clipped and the clipping device  24  can operate free from obstruction by the conveyor  80 . 
   Apparatus  94 , including at least one conveyor drive cylinder  70 , is provided to cause the conveyor to retract to increase the space  92  when gatherers  96  for the clipping device  24  are operating to gather stuffed food casing  12  to form a radial restriction  72  in the stuffed food casing  12  and to extend to reduce the space  92  and place the conveying surface  90  near the clipping device  24  when the gatherers  96  are dormant. The stroke of the apparatus, for increasing and decreasing the space, is adjustable to permit distance between sets of gathering arms  96  to be increased and decreased thus permitting an unstuffed length of casing between the closed sets of gathering arms  96  to be withdrawn from the stuffing horn  16  to allow for slack filled (incompletely filled) casing  12 , as shown in FIG.  3 .