Abstract:
An apparatus and method for ballooning and peeling the casing of a cooked meat stick such as cured pepperoni. Prior to peeling the casing from the meat stick, a needle pierces the casing and air is then injected through the needle and between the casing and the meat kernel therewithin so as to ballooningly separate the casing from the meat kernel. A gripper, preferably using jaws, grip one end of the casing and hold the casing to a casing drum. The casing is split longitudinally by a knife, and, as the casing drum rotates, the casing is wound onto the casing drum and forcibly pulled from the cooked meat stick. After the casing has been fully wound onto the casing drum and thus removed from the meat stick, the gripping jaws release the casing and a casing ejector slides the wound casing from the casing drum. A position detector is used to sense when the casing drum is in the correct rotational position to have the gripper grab the next cooked meat stick&#39;s casing end, and a brake slows and stops the rotation of the casing drum in the correct home position.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates, in general, to apparatus and methods for removing the skins and casings from meat products, and in particular, to an apparatus and methods for removing the skins and casings from cooked meat sticks such as cured cooked sticks of pepperoni. 
     2. Description of Related Art 
     Meat products producd in stick form, such as pepperoni sausages, are traditionally formed in a stuffing operation in which the sausage emulsion is stuffed into a skin or casing, such as a plastic or cellulose casing. The sausage stuffed casings may then be clipped, smoked, and further processed until the sausage is completely formed. After a sausage is formed, the casing is often removed to permit slicing of the sausage sticks for sale to consumers or institutions. 
     It is often desired to remove the skins and cellulose casings from stick-type meat products such as wieners, frankfurters, and pepperoni to permit repackaging or further processing of the products. Prior art solutions for this problem include slitting the skin or casing in which the meat product was cooked and then using air nozzles, steam, and vacuum to peel the encased meat from the outer casing. Removal of casings from frankfurter links and wiener links is rather straightforward, as taught, for example, in Klyce et al., U.S. Pat. No. 5,295,895, because such meat products are processed to allow the captive meat sticks or kernels to float or slip inside their cellulose casings. 
     However, such prior art methods may be inadequate to remove the casing from larger stick-type cured meats such as pepperoni, where the curing cycle causes the casing to strongly adhere to the meat stick, thereby causing great difficulty in removing the casing from the meat stick. Additionally, while steam processing has been used to remove the skins from wieners and frankfurters, such steam processing adds expense and complexity and is often unacceptable with large stick-type meat products and cured meat products. As a result, cured meat products such as five-foot (1.5 meter) long sticks of pepperoni have traditionally been peeled by hand using a knife. 
     It is therefore desirable, have an automated and high-throughput apparatus and method for removing the casing from cooked meat sticks and especially from cooked cured meat sticks such as sticks of pepperoni. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is an apparatus and method for ballooning and peeling the casing of a meat stick such as cooked or cured pepperoni. Prior to peeling the casing from the meat stick, the casing may be “ballooned” by piercing the casing with a needle and injecting air through the needle between the casing and the meat kernel to separate the casing from the meat kernel. Grippers grip one end of the casing and hold the casing for rotation about a casing drum. The casing is split longitudinally by a knife, and, as the casing drum rotates, the casing is wound onto the casing drum and forcibly pulled from the meat stick. After the casing has been fully wound onto the casing drum and thus removed from the meat stick, the gripper and/or gripping means releases the casing and a casing ejector removes the wound casing from the casing drum. A home position detector may be used to sense when the casing drum is in the correct rotational position to have the gripper device grab the next cooked meat stick&#39;s casing end, and a brake may slow and stop the rotation of the casing drum in a desired position, such as the home position. 
     It is an object of the present invention to provide an apparatus and method for ballooning and peeling the casing of a cooked meat stick, such as cured pepperoni. 
     It is a further object of the present invention to peel the casing from the meat stick by providing more stripping power and force for removing the casing than heretofore possible using apparatus and methods of the prior art. 
     It is a still further object of the present invention to provide a higher-throughput automated apparatus and method for removing the casing from a cooked meat stick than heretofore possible, without requiring the use of steam to separate the casing from the meat stick. 
     It is yet another object of the present invention to facilitate the handling and disposal of casing waste products. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     FIG. 1 is a top plan view of the peeling apparatus and ballooning apparatus of the present invention. 
     FIG. 2 is a side view of the peeling apparatus of the present invention, taken substantially along the line  2 — 2  shown in, FIG. 1, but with the brake calipers and the home position index sensor removed to show structure that would otherwise be hidden. 
     FIG. 3A is a sectional view of the ballooning apparatus of the present invention taken substantially along the line  3 — 3  shown in FIG. 1, showing the hollow needle prior to penetration of the casing of the meat stick. 
     FIG. 3B is a sectional view of the ballooning apparatus of the present invention, similar to FIG. 3A but showing the hollow needle penetrating the casing of the meat stick. 
     FIG. 4 is an end view of the peeling apparatus and ballooning apparatus of the present invention showing the gripping and slitting of the casing of the meat stick. 
     FIG. 5 is a longitudinal sectional view of the casing drum of the present invention, taken substantially along the line  5 — 5  shown in FIG. 16, showing the details of the gripper, with the casing ejector shown in the ejection pre-grip position. 
     FIG. 6 is a longitudinal sectional view of the casing drum of the present invention, somewhat similar to FIG. 5 but with the casing ejector shown in an intermediate position. 
     FIG. 7 is a longitudinal sectional view of the casing drum of the present invention, somewhat similar to FIG. 6 but with the casing ejector shown in the gripping position. 
     FIG. 8 is a transverse sectional view of the casing drum of the present invention, taken substantially along the line  8 — 8  shown in FIG.  5 . 
     FIG. 9 is a transverse section view of the casing drum of the present invention, taken substantially along the line  9 — 9 , shown in FIG.  6 . 
     FIG. 10 is a longitudinal sectional view of the casing drum of the present invention as viewed from below the gripper. 
     FIG. 11 is a side view of the parts of the linkages of the gripper. 
     FIG. 12 is a side view of the gripper with the jaws opened. 
     FIG. 13 is a side view of the gripper with the jaws closed. 
     FIG. 14 is a top view of the casing drum of the present invention showing casing wound thereon and with the casing ejector shown in an intermediate position. 
     FIG. 15 is a top view of the casing drum of the present invention with the casing ejector shown in the ejection pre-grip position. 
     FIG. 16 is an end view of the casing drum of the present invention with the gripper removed. 
     FIG. 17 is an end view of the peeling apparatus and ballooning apparatus of the present invention, similar to FIG. 4, but after an initial revolution of the casing drum and showing the winding of the casing thereon. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, the preferred embodiment of peeling apparatus  20  is seen to comprise a casing drum  22  mounted for rotation upon an axle or drive shaft  24  that defines an axis  26  of rotation. Rotation of the drive shaft  24  could be accomplished by any of a number of powered rotation devices  28  for rotating the casing drum  22  but is preferably accomplished by an electric motor  30  coupled to a drive shaft  24  by a drive belt  32  that encircles and engages a drive pulley  34  on the shaft of the motor  30  and a driven pulley  36  coupled to the drive shaft  24  so as to cause mutual rotation of the drive pulley  34  with the driven pulley  36 . The drive shaft  24  is mounted for rotation by a pair of pillow-block bearings  42 ,  44 . 
     A reciprocating shaft  23  reciprocates in response to action of an air cylinder  38 , whose reciprocating piston is coupled to the reciprocating shaft  23  through a rotational coupling  40 , thereby allowing the reciprocating shaft  23  to reciprocate longitudinally from a first position shown in FIGS. 1 and 2 to reciprocated positions as indicated, for example, by a rotational coupling  40  being shown in one such reciprocated position in dotted outline  40 ′ in FIGS. 1 and 2. In order to permit independent rotation of the drive shaft,  24  and reciprocation of the reciprocating shaft  23 , the driven pulley  36  is preferably coupled to the drive shaft  24  so that the driven pulley  36  may rotate the drive shaft  24  and while permitting reciprocation of the reciprocating shaft  23 , preferably within the center of the drive shaft  24 . 
     Referring especially to FIGS. 1 and 4, large stick-type meat products such as a pepperoni stick P have a cellulose casing C covering the cured and processed meat kernel within. Typically, each end  46 ,  48  of the pepperoni stick P is either tied or secured with a metal clip, leaving about a 1.5 inch (3.8 cm) tab protruding from each end  46 ,  48  of the pepperoni stick. It should be understood that, in FIGS. 1 and 4, reference numerals  46 ′,  48 ′, and P are used to indicate, by dotted outline, the position of the corresponding portions of the pepperoni stick prior to movement into the positions shown in solid outline. It should also be understood that pepperoni sticks are used as an exemplary meat product processed by the present invention, but that other stick-type meat products having casings, most typically relatively hard or firm stick-type products with difficult-to remove casings, may be peeled by the apparatus and method of the present invention. 
     Referring especially to FIGS. 5-13, peeling apparatus  20  further includes a holder for selectively holding a portion of the casing C, preferably the tab at the leading end  48  of pepperoni stick P, to the casing drum  22  such as the clamp  50 , illustrated. The clamp  50  preferably comprises first and second opposed jaws  52 ,  54  mounted for movement upon a pivot pin  56  that is fixedly secured within the casing drum  22  as by screws  58  that secure pivot pin mounting blocks  60 ,  62  to the casing drum  22  as shown in FIG.  10 . As shown in FIGS. 11-13, opposed jaws  52 ,  54  preferably may have matingly interlocking teeth on the contacting jaw faces to better entrappingly grab and grip the casing or the leading end  48  of the pepperoni stick P. 
     Opposed jaws  52 ,  54  may be opened and closed by a linkage mechanism  63  that operates in response to the reciprocation of lateral straps  64 ,  66  in a manner fully explained in detail hereinbelow. Oblong slots  68 ,  70  are respectively provided through the lateral straps  64 ,  66  to allow the lateral straps  64 ,  66  to reciprocate with respect to the pivot pin  56 . It shall be understood that, for purposes of explanation and to better view the operation of linkage mechanism  63 , the lateral strap  64  is removed from the views shown in FIGS. 12 and 13. Additionally, other systems known in the art could be utilized to actuate the jaws  52 ,  54 . 
     Referring especially to FIGS. 10-13, the linkage mechanism  63  can now be explained. An end link  72  is pivotally joined at its ends to first ends of Y-shaped upper and lower intermediate links  74 ,  76  which, in turn, are respectively pivotally joined at their second opposite ends to the first and second opposed jaws  52 ,  54 . End link  72  may be mutually reciprocated together with lateral straps  64 ,  66  with respect to pivot pin  56 , as best seen by comparing FIG. 12 with FIG. 13, to open and close jaws  52  and  54 . 
     As best seen in FIGS. 9 and 10, the reciprocating shaft  23  may be fixedly secured to a drum rotation disk  78  by a bolt  80  so that the drum rotation disk  78  is caused to reciprocate with the reciprocating shaft  23 . The drum rotation disk  78  preferably has oblong slots  82 ,  84  for respective passage therethrough of the lateral straps  64 ,  66  and for allowing the drum rotation disk  78  to reciprocate with respect to lateral straps  64 ,  66 . 
     As best seen in FIGS. 5-10, the lateral straps  64 ,  66  may each be secured at one end to an end link  72  as by screws  86  and at the opposite end by screws  88  to a jaw actuation member  90 . It will be understood that, as the jaw actuation member  90  is caused to reciprocate with respect to the pivot pin  56 , the coupling through lateral straps  64 ,  66  to the end link  72  causes the jaws  52 ,  54  to open and close. 
     FIGS. 5-7 also illustrate the relationship of the drive shaft to the reciprocating shaft  23 . The drive shaft  24  is preferably operatively coupled to the casing drum  22  to rotate the casing drum  22 . The drive shaft  24  may be connected to the rear of the casing drum  22  by a flange member such as rear plate  96  which may be bolted or otherwise connected to the casing drum  22 . 
     FIG. 7 illustrates the reciprocating shaft  23  located within the drive shaft  24   24 . FIG. 1 and 2 show the opposite end of reciprocating shaft  23  connected at one end to the reciprocating piston of the air cylinder  38  at the rotational coupling  40 . When the drive shaft  24  rotates, the rotational coupling  40  preferably allows the reciprocating shaft  23  to rotate with the drive shaft  24 . 
     Referring to FIGS. 5-7, the jaw actuation member  90  is shown resting against a plurality of springs  92 ,  94  entrapped within bores  93  through the endwall of the casing drum  22 . As illustrated, one end of springs  92 ,  94  rests against receivers, such as guide plugs  89 , located on the jaw actuation member  90  and the other end of springs  92 ,  94  resting against a rear plate  96  secured to the endwall of the casing drum  22 . The plugs  89  may be received within the bores  93  when the jaws  52 ,  54  are in a closed position to provide additional torsional strength to the holder during rotation of the casing drum  22 . Through this construction, the jaws  52 ,  54  may be spring loaded into the open position by springs  92 ,  94 . Adjustment screws  98 ,  100 , with respective locking nuts  102 ,  104 , may also be utilized to allow the force exerted by the springs  92 ,  94  to be adjusted. 
     The preferred operation of an ejector  105  and the clamp  50  is illustrated in FIGS. 5-7. In FIG. 5, the reciprocating shaft  23  is shown extending substantially into the casing drum  22  thereby positioning the ejector  105  is in an ejecting position. The end of the reciprocating shaft  23  is preferably connected to the drum rotation disk  78  which is in turn connected to the ejector ring  114 . As the reciprocating shaft  23  is partially withdrawn, it results in the drum rotation disk  78  moving toward the rear of the casing drum  22  with the reciprocating shaft  23 . The ejector ring  114  moves to the position illustrated in FIG. 6 with the partial withdrawal of the reciprocating shaft  23 . At least a portion of the drum rotation disk  78  is illustrated cooperating with the jaw actuation member  90  to operatively engage the jaw actuation member  90  such that further reciprocation of the reciprocating shaft  23  moves the jaw actuation member  90  to compress springs  92 ,  94  and move lateral slats  64 ,  66  rearward as is illustrated in FIG.  7 . As described above, rearward movement of lateral slats  64 ,  66  relative to pivot pin  56  causes the jaws  52 ,  54  to shut. 
     As hereinafter described in detail and as shown in FIGS. 14 and 17, after securing the casing C at holder  50 , casing C is removed from the pepperoni stick P by winding the casing C upon rotating casing drum  22  by as the pepperoni stick P passes transversely over the rotating casing drum  22 . Referring to FIGS. 14 and 15, once the casing C has been removed from the pepperoni stick P and wound upon the casing drum. 22 , the wound casing C is then preferably ejected from casing drum  22  by a casing ejector  105 , in a manner that will now be described. The casing drum  22  may have a plurality, preferably four, of longitudinal slots  106  within which a like number of respective radially-extending casing ejector ribs  108  reciprocate. Each of the casing ejector ribs  108  may be secured to the drum rotation disk  78  by a screw  110  so as to cause mutual rotation and/or reciprocation of casing ejector ribs  108  with drum rotation disk  78 , thereby causing mutual rotation of casing drum  22  with reciprocating shaft  23  when, or if, the reciprocating shaft is rotating. 
     As best seen in FIGS. 14-16, circumferentially around the casing drum  22  and secured to casing ejector ribs  108 , as by screws  112 , is a casing ejector ring  114 . The casing ejector ring  114  need not be a complete ring, but may be C-shaped with a gap aligned with the open mouth  116  of the casing drum  22  through which the jaws  52 ,  54  are accessed by the end  48  of the pepperoni stick P. Additionally, a guide, illustrated as roller  118 , may be mounted to the casing ejector ring  114  and extend longitudinally rearwardly therefrom alongside the top lip of mouth  116  when the casing ejector  105  is fully reciprocated into the ejection pre-grip position shown in FIGS. 5 and 15. A semi-cylindrical longitudinal recess  120  may be provided on the outer surface of the casing drum  22  so as to allow roller  118  to reciprocate rearwardly with casing ejector ring  114  from the ejection pre-grip position. 
     The casing ejector  105  preferably includes a contacting portion  122 , such as the face of casing ejector ring  114 , that reciprocates substantially parallel to the axis  26  of the casing drum  22  from a casing winding position to a first ejector position such as the intermediate position shown in FIGS. 6 and 14, to a second ejector position such as the ejection pre-grip position shown in FIGS. 5 and 15. In moving toward th second ejector position, the contacting portion  122  forcibly and contactingly urges wound casing C longitudinally along the casing drum  22  and expels casing C off of the casing drum  22  as shown in FIG.  15 . Advantageously, the wound casing C may be relatively compact and easily managed for disposal relative to the lengthy peeled casings produced under the prior art. 
     In FIGS. 5 and 15, the reciprocating shaft  23  has been reciprocated forward within the drive shaft  24  toward the casing drum  22  by air cylinder  38  such that jaws  52 ,  54  are held open by springs  92 ,  94  and so as to place the casing ring  114  into the ejection pre-grip position, thereby forcing any casing C to slide longitudinally off of the casing drum  22  and into a trash receptacle (not shown). Note that, in this pre-grip position in which the end of the next pepperoni stick is inserted into the open mouth of the casing drum  22  and into the jaws  52 ,  54 . A guide member such as the roller  118  is preferably positioned alongside the open mouth of the casing drum  22  so as to direct the passage of the end of the pepperoni stick into the jaws  52 ,  54 . 
     In FIGS. 6 and 14, the reciprocating shaft  23  has been partially reciprocated rearwardly by the air cylinder  38  to an intermediate position. The jaws  52 ,  54  may still be held open by springs  92 ,  94 , but preferably, the guide roller  118  is no longer positioned alongside the open mouth of the casing drum  22 . 
     In FIG. 7, the reciprocating shaft  23  has been fully reciprocated rearwardly by the air cylinder  38  to a gripping position. The rearward reciprocation of the drum rotation disk  78  against jaw actuation member  90  has compressed springs  92 ,  94 , and the jaws  52 ,  54  are in the fully closed position and are gripping the end  48  of casing C. 
     Referring to FIGS. 1 and 2, the peeling apparatus  20  further preferably includes a brake  124  for retarding and stopping rotation of the casing drum  22 . The brake  124  preferably comprises a caliper brake mechanism including a brake disk  126  mounted to the drive shaft  24  for mutual rotation. The brake  124  allows the reciprocating shaft  23  to reciprocate with respect to the brake disk  126 . The brake  124  also may utilize disk pads  128  that are frictionally pressed against the brake disk  126  by calipers  130  so as to retard and stop the rotation of the brake disk  126  and thereby to retard and stop the rotation of the casing drum  22 . 
     A peeling apparatus  20  may include a position detector  132  for detecting the rotational position of the casing drum  22 . Accordingly, the mouth  116  may be positioned as shown in FIGS. 1 and 16 for entry of the leading end of the pepperoni casing to be gripped by the gripper  50 . The illustrated position detector  132  includes an indexing disk  134  connected to the drive shaft  24  for mutual rotation with both the drive shaft  24  and the casing drum  22 . The indexing disk  134  may have a hole or slot  136  at a selected angular position such that a sensor  138 , such as an LED sensor, may monitor the slot  136  to sense when the casing drum  22  is at the rotational position in which the mouth  116  is in correct alignment for beginning a peeling cycle. 
     The peeling apparatus  20  also preferably includes a gripping position sensor, such as a switch  140  actuated by the rearward positioning of the rotational coupling  40  capable of sensing when the ejection means is in a gripping position. 
     Referring to FIGS. 4 and 17, the peeling apparatus  20  further includes a knife  142  mounted for engaging and longitudinally slitting the casing C of the food stick with a covering, such as the pepperoni stick P, by a sharp blade  144  of the knife  142 . If desired, the knife  142  may be spring loaded to exert a known pressure on the casing of the pepperoni stick P, or it may be fixedly adjusted to match the size and casing thickness of the pepperoni stick P. When used in conjunction with a ballooning apparatus  200  as hereinafter described, the knife  142  may be provided with a retractor for retracting knife  142  from casing C until ballooning has been completed, as by clockwise rotating knife  142  about its mounting axis  143  as viewed in FIG.  17 . 
     Referring now to FIGS. 1,  3 A, and  3 B, the present invention may further include a ballooning means and/or ballooning apparatus  200  for lifting the casing C from the pepperoni stick P prior to peeling the casing C from the pepperoni stick P. As used herein, the term “ballooning” shall be understood to mean the condition of introducing a fluid, preferably air, into an enclosed cavity, such as the interior of the casing C. The introduction of air may be controlled through at least the injected pressure and length of time of introducing air into the casing C. The controlled air introduction may vary according to the given volume of the meat stick so as to create the condition of separating the casing C from the meat kernel therewithin. Because the ballooning may pressurize the interior of the casing C, it is preferred that the ballooning step be performed before the knife  142  penetrates the casing C. Accordingly, the ballooning apparatus  200  is placed upstream of the peeling apparatus  20  so that ballooning may occur prior to peeling. 
     The pepperoni stick P may be placed between guides  202  and moved longitudinally toward the ballooning apparatus  200 . When the pepperoni stick P reaches the proper position for ballooning, a position sensor, such as a switch  204 , is actuated and the ballooning cycle begins. 
     The ballooning apparatus  200  comprises a needle  206  for piercing the casing C of the pepperoni stick P, an insertion device  208  for causing the needle  206  to pierce casing C, and an air supply  210 , such as a tank of pressurized air exiting through an air supply control valve  211  interposed within a tube or pipe  212 , for forcing pressurized air through needle  206  while casing C is pierced by the needle  206 . The insertion device  208  is preferably an air cylinder  214  that causes a ballooning head  216  to move the needle  206  toward and piercingly into casing C when the pepperoni stick P is secured against a guide jig  218 . 
     To use the ballooning and peeling apparatus of the present invention, a pepperoni stick P is placed between guides  202  and moved longitudinally toward the ballooning apparatus  200 . When pepperoni stick P reaches the proper position for ballooning, switch  204  is actuated and the ballooning cycle begins. Air is forced through needle  206  into the casing C for a predetermined length of time and at a predetermined pressure, and casing C is ballooningly separated from the encased meat kernel. 
     The peeling apparatus  20  preferably begins a cycle in the ejection pre-grip position, the casing drum  22  remaining begins a cycle in the home position from the previous cycle, with the brake  124  energized to prevent rotation. 
     After predetermined delay following the ballooning cycle, the knife  142  may be positioned to slice casing C. The leading end or tab of the casing C may be inserted through the mouth  116  of the casing drum  22 , past the roller  118 , and into the open jaws of gripping means  50 . The air cylinder  38  may then be pressurized to move reciprocating shaft  23  rearwardly to cause drum rotation disk  78  to move jaws  52 ,  54  into the gripping position and securely grip the leading tab end of cellulose casing C. The brake  124  may then be released to allow rotation of the casing drum  22 . When gripping position sensing switch  140  detects that the gripping position has been entered, rotation of the casing drum may begin by applying power to motor  30 . As the casing drum  22  rotates, the casing C is wound onto the casing drum  22  as shown in FIG. 17 with the knife  142  creating a longitudinal slit in the casing C so as to allow the casing to be pulled from the pepperoni stick P by the winding force of the casing drum  22  as the peeled pepperoni stick P passes transversely over the casing drum  22 . The rotating action of the casing drum  22  applies a strong stressing motion to the casing, thereby pulling it from the pepperoni stick P. After the end of the product is detected by a position sensing switch  204  (or, alternatively, by the detection of the knife  142  position as a result of the casing no longer being sliced thereunder), the cycle termination begins. Rotation continues until the home position is detected by the position detector  132 , at which time the brake  124  may be energized to lock the casing drum rotationally in the home position. The air cylinder  38  may be pressurized to move reciprocating shaft  23  into the forward position to cause the holder  50  to release the casing C in the ejection pre-grip position, thereby ejecting the wound casing. C from the casing drum  22  as shown in FIG.  15 . The cycle may then be repeated. 
     In a preferred embodiment, ballooning head  216  presents a convex face to also serve as a guide and promote the relatively even inflation of the casing circumferentially and longitudinally. The sequencing and operation of the present invention including both ballooning and peeling steps may be controlled by a programmable computer or programmable logic controller (“PLC”). 
     The peeling method of the present invention is preferably used in combination with the ballooning method of the present invention by practicing the steps of the ballooning method prior to practicing the peeling method step of winding the casing on the casing drum. 
     Although the present invention has been described and illustrated with respect to a preferred embodiment and method and a preferred use therefor, it is not to be so limited since modifications and changes can be made therein which are within the full intended scope of the invention.