BACKGROUND OF THE INVENTION 
     The present invention relates generally to a new and useful apparatus and method for packaging food products, and more specifically, to improved devices and methods for more economic packaging of sausage products in tubular food casings. 
     In the manufacture of sausage products, meat emulsion is prepared from communited meat together with fillers, seasonings, spices, etc. A tubular food casing, such as nonedible cellulose, is loaded onto the stuffing horn of a filling machine and stuffed with the meat emulsion. In the case of small sausage products, like frankfurters, the filled casings are twisted, tied or clipped into suitable links at predetermined intervals and further processed. For larger sausage products, like bologna, salami, and the like, the meat emulsion is introduced into larger, heavier walled fibrous type casings and formed into chubs or lengthy individual sausage sticks. 
     In preparing large diameter sausage products, like bologna, an important consideration is the maintenance of accurate size control over the entire length of the sausage stick. It is important that the diameter of large sausage products be controlled very carefully so that meat packers are able to cut the sausage into slices of predetermined thickness and diameter for prepackaging. The objective is to have a given number of slices weigh precisely a predetermined amount for each package. In other words, a given number of slices should weigh exactly one pound or some other preselected weight. 
     A further important consideration, in the preparation of large diameter sausage products for prepackaging, concerns end portions. Sticks, having either tapered ends or enlarged bulbous ends, provide poor yields. The end portions of a bologna, for example, which are either undersized or oversized can result in the loss of up to five inches of meat from each end of the sausage product, since off-spec slices cannot be used for prepackaged meat products. In addition to forming packages which fail to meet required preselected weight standards, sliced product prepared from sticks having bulbous ends cannot be enclosed in display packages. 
     As a result of the problem of filling equipment forming packages with ends which result in substantial waste, meat processors and equipment manufacturers are constantly striving to improve both operations and machines that affect finished package yield. For example, U.S. Pat. No. 3,621,513 discloses a stuffing apparatus which is capable of forming sausages with a variety of end portion configurations, including tapered, elongated ends and taut ends whose rounded end portion have been reduced and minimized. To prepare filled casings with taut, nontapered ends, when the flow of emulsion is terminated a dished shaped platen is needed to compress and aid in shaping the trailing end of the filled casing by moving downstream from the stuffing horn outlet against the filled casing. Simultaneously, an internal casing presizer engaged with the stuffing horn is maintained in an expanded, operative mode to restrain the release of unfilled casing from the horn. Consequently, increased pressure is exerted against the trailing end of the filled casing by the dished platen. While in this position a clipper unit is actuated to close the casing. 
     Filled casings with tapered ends may also be prepared with the apparatus of U.S. Pat. No. 3,621,513. In this regard, elongated ends are formed by contracting the casing presizer to release unfilled casing from the horn after operation of the food pump is terminated. The dished platen is then moved downstream from the stuffing horn stripping casing from the horn while permitting some of the food emulsion to flow upstream into the unfilled loose casing where the casing is clipped. Accordingly, the methods and apparatus of U.S. Pat. No. 3,621,513 are dependent on a multiplicity of components, including concentric sleeve casing presizer, casing brake, emulsion stopping ring, dished platen, casing clippers, etc. 
     U.S. Pat. No. 4,562,617 discloses means for preparing dimensionally uniform filled food casings with nontapered ends. The uniform filled casings are prepared by introducing with the food product &#34;a closing piece&#34; inside the casing at the terminal ends. The closing pieces occupy interior space which otherwise would have been filled with meat emulsion to produce tapered ends. U.S. Pat. Nos. 4,028,775 and 4,160,305 also relate to apparatus and methods of inserting sizing discs into tubular casings. 
     U.S. Pat. No. 3,454,980 to H. G. Washburn and U.S. Pat. No. 3,553,768 to G. M. Wilmsen also disclose means for sizing control in stuffing operations. Devices disclosed therein rely on tubular sleeves for improving sausage diameter uniformity. Variations in sausage diameter are corrected by means of an annular ring which engages a conical face on the edge of the stuffing horn to control the rate of casing feed off the horn. Thus, to enlarge undersized sausage to a predetermined diameter during the stuffing cycle, pressure of the annular ring against the casing on the edge of the stuffing horn is increased in order to increase the friction and slow the rate at which unfilled casing is released from the horn. Similar adjustments are made in correcting for oversized diameters during the stuffing cycle, except that fricitonal pressure against the casing on the horn is reduced allowing the empty casing to be released more freely from the horn. 
     According to U.S. Pat. No. 3,454,980 variations in sausage diameter are constantly monitored and automatically corrected by a pneumatic sensing device in combination with a fluid motor, the latter of which controllably adjusts the frictional pressure applied to the casing at the conical edge of the stuffing horn by lateral movement of the annular ring. Although the Washburn and Wilmsen devices are effective in achieving accurate size control, they do not provide means for restricting the backflow of food emulsion over the stuffing horn during the closure cycle. In addition, no specific means are provided for making substantially flattened terminal ends for minimizing potential waste and lower product yield. 
     A further sizing apparatus is disclosed by Niedecker in U.S. Pat. No. 3,748,690 wherein an axially slideable snubbing element on the stuffing horn is displaced forwardly downstream after the completion of the filling cycle to push or release unfilled casing from the horn when the clipper gates are actuated. Like many of the foregoing filling machines, the methods of Niedecker fail to provide means for minimizing tapering or enlarged rounded ends. Accordingly, there is need for a sausage stuffing apparatus with improved sizing control means for making filled casings with terminal end portions which are neither tapered nor enlarged, such improved means not being dependent either on the introduction of special casing inserts or multiple machine components. 
     SUMMARY OF THE INVENTION 
     The present invention relates generally to methods and apparatus for automatically stuffing shirred food casings, and especially for prepreparing large size sausage products for prepackaging which products are dimensionally uniform and have substantially flat terminal end sections. 
     Although the methods and apparatus described herein may be used for stuffing nonfibrous, unreinforced food casings, including casings of relatively short length, they are especially desirable for stuffing shirred fibrous, reinforced type casings which have been pleated into individual strands of substantial length, e.g. 200 feet or more, or stuffing multiple large size sausage and other food products, such as bolognas, salamis, etc. The fibrous casings may include premoistened, ready-to-stuff types sufficiently moistened for stuffing at the time of their manufacture. Alternatively, conventional strands of fibrous casing may be used requiring soaking immediately prior to stuffing. 
     Because the stuffed food products are uniform in diameter, end-to-end, meat packers are able to cut them into slices of predetermined thickness and diameter for prepackaging with the expectation of forming packages of identical weight. Sticks so formed have higher average product yields due to substantially flat, nontapered, nonrounded ends. 
     Generally, the stuffing apparatus of the present invention comprises a stuffing horn with an inlet for receiving a presurized food material, e.g. sausage emulsion from a food pump, an outlet downstream from the inlet for delivering the food material to a casing loaded onto the stuffing horn and a shaft intermediate to the inlet and outlet of the stuffing horn; means for engaging the casing against the shaft of the stuffing horn for restricting the rate of release of casing therefrom; carriage means for translating the casing engaging and restricting means along the axis of the stuffing horn; the casing engaging and restricting means including means for preventing the backflow of food material when the backflow preventing means is removed from the shaft of the stuffing horn; means for closing off filled casing, and means for controlling the length of the interval from actuation of the closing off means to actuation of the carriage means for removing the backflow preventing means from the shaft of the stuffing horn. 
     More specifically, the casing engaging and restricting means can comprise a resilient sizing ring for engaging the casing circumferentially against the stuffing horn, means for applying compressive forces uniformly to the sizing ring to regulate the rate of release of unfilled casing from the stuffing horn during the filling cycle, motor means for driving the carriage means with the casing engaging and restricting means downstream sufficiently to remove the sizing ring from the stuffing horn during the closing cycle allowing the release of unfilled casing from the horn while also preventing the backflow of food material over the exterior surface of the stuffing horn. 
     In addition to the foregoing apparatus, the present invention also includes methods for stuffing shirred strands of food casing comprising the steps of loading a strand of the casing for stuffing at a filling station during the filling cycle; stuffing the casing with the food material at the filling station while applying a force to restrict the rate at which unfilled casing is released for stuffing; closing the trailing end of the filled casing at the clipping station during the closing cycle, an controlling the interval for withdrawing the force restricting the rate of release of unfilled casing at the filling station when the trailing end of the filled casing is closed so that the length of the interval is directly proportional with the viscosity of the food material at the time of the filling cycle. That is to say, in order to form ends which are substantially flat and which are neither tapered nor rounded/bulbous the force restricting the release of unfilled casing is maintained for an interval which is directly proportional to the flow properties of the emulsion. Thus, where the physical properties of a food material at the time of stuffing have a relatively low level of resistance to flow the interval between actuation of the clipper mechanism for closing the trailing end of the filled casing and removal of the sizing ring from the stuffing horn to release unfilled casing is substantially nil. That is, the end-closure mechanism and the mechanism releasing unfilled casing are actuated substantially simutaneously. However, as the food material becomes less fluid and more viscous, as in cold stuffing, the delay for releasing unfilled casing at the time the clipper mechanism is actuated increases. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     For a further understanding of the invention as well as its characterizing features, reference should now be made to the following detailed description thereof taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a partial side view of a representative filled food casing prepared according to the present invention. 
     FIG. 2 is a partial side view of a filled food casing having rounded/bulbous ends. 
     FIG. 3 is a partial side view of a filled food casing having tapered ends. 
     FIG. 4 is a top plan view of the apparatus with certain parts removed for clarity. 
     FIG. 5 is a side elevation view of the apparatus of FIG. 4 with certain parts removed for clarity. 
     FIG. 6 is a side sectional view of the casing engaging and restricting means with sizing ring engaged with the shaft of the stuffing horn during the filling cycle, taken along line 6--6 of FIG. 8. 
     FIG. 7 is a partial side sectional view of the casing engaging and restricting means of FIG. 6 with the sizing ring moved off the shaft of the stuffing horn during the closing cycle. 
     FIG. 8 is a sectional view of the apparatus taken along line 8--8 of FIG. 5 with certain parts removed. 
     FIG. 9 is a sectional view of the apparatus taken along line 9--9 of FIG. 5. 
     FIGS. 10--12 are elevational, side sectional views illustrating the steps of stuffing and clipping casing according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning first to FIG. 1 there is shown a partial view of a dimensionally uniform filled casing 10 with an end-closure clip 12 wherein terminous portion 14 of the filled product is substantially flat. Because filled casing 10 is dimensionally uniform, end-to-end the majority of terminous portion 14, which is neither undersized nor oversized, can be sliced by food processors with the expectation that they can be satisfactorily used in prepackaging. FIG. 2 provides a partial view of a filled casing 16 with an end-closure clip 18 and an enlarged terminous portion 20 which is rounded/bulbous in shape compared to end portion 14. Similarly, FIG. 3 illustrates a filled casing 22 with an end-closure clip 24 and an undersized terminous portion 26 which has a tapered shape. Product yield for sliced prepacked sausage, e.g. bologna, prepared from sticks having either oversized or undersized end portions, like those shown in FIGS. 2 and 3, provide substantially lower product yield than sticks having substantially flat end portions like those of FIG. 1. The oversized and undersized terminous portions 20 and 26 of sticks 16 and 22, respectively would have to be removed as waste before the balance of the stick could be cut into slices of uniform weight and diameter. 
     Food sticks according to FIG. 1 can be prepared with stuffing apparatus 28 (FIG. 4) consisting of four main sections: a food delivery section 30, a product sizing section 32, a product closing section 34 (FIG. 5), and a product receiving and discharging section 36 (FIGS. 4 and 5). The four sections are mounted on a frame assembly 38 comprising an outer frame 40 with cross supports 42, all supported by leg members 44. 
     The food delivery section 30 is intended for receiving a pressurized food material, e.g. meat emulsion, from a meat pump (not shown) upstream of the apparatus. The pump is joined at tubular connection 46 for transporting the pressurized food to a casing, usually a pleated strand of tubular material 48 (FIG. 5), at the outlet end of the stuffing horn 50. More specifically, a meat emulsion or other stuffable food product is received by a horn assembly comprising a stuffing horn 50 detachably joined to a rotatable hub 52 by means of connectors 54. The hub accommodates horns of varying size depending on the diameter of the casing being filled. The hub 52 is supported for rotational movement through an internal connecting shaft 56 (FIG. 5) which pivots in a stationary sleeve 58 mounted to frame 40. Articulation of hub 52 and stuffing horn 50 from a central position (FIG. 4) to an off center position shown by broken lines provides convenient access for loading shirred casing onto the horn. 
     Rotational drive for the horn and hub is provided by fluid motor 60 detachably connection to frame 40 through support member 62. Motor 60 includes fluid lines 64 and 66, and rod 68 connected to the hub through yoke extension 70. Actuation of fluid motor 60 to retract rod 68 causes a pivoting movement of the hub and of the outlet end of the horn to the side loading position. Extension of rod 68 of motor 60 returns horn 50 to center operating position. It should be noted, that for operator convenience fluid motor 60 can also be connected to the opposite side of frame 40 through support member 72 (FIG. 4) so that retraction of rod 60 will cause the outlet end of the horn to pivot to the opposite side of the apparatus. This will provide added flexibility for operators in setting up conveniently positioned work stations for greater accessibility for more efficient operation of the machine. 
     Product sizing section 32 provides means for making dimensionally uniform filled casings during the stuffing cycle. The principal elements of the product sizing section are casing brake assembly 74 for engaging unfilled casing against the horn for restricting the rate of release of casing, and axially translatable carriage 76 for the casing brake assembly. The casing brake assembly shown in FIG. 5 is mounted to carriage 76 through flange 78. Carriage 76 includes a slideable platform 80 comprising cross supports 81 mounted on spaced parallel rails 82 and 84 (FIG. 4) through openings in multiple platform legs 86. The openings in platform legs 86 are lined with bushings 87. Rails 82 and 84 are mounted to outer frame members 40 through rail connectors 88. 
     Carriage 76 is driven by fluid motors 90 and 92, connected to one another in a back-to-back arrangement, wherein the front end of motor 90 has its rod 94 engaged with cross-support 81. When actuated via fluid lines 96 and 98 motor 90 extends rod 94 downstream moving carriage 76 sufficiently to clear casing brake assembly 74 from the horn so that the horn is free to be pivoted sidewardly to casing loading position. After returning the horn to stuffing position, rod 94 is retracted to return the carriage and casing brake assembly so that the latter is positioned over the horn during the stuffing cycle. 
     As previously indicated, the back end of fluid motor 92 is linked to the back end of fluid motor 90. Fluid motor 92 has a rod 100 affixed to outer frame 40 through connector 102. Because rod 100 is anchored to the frame actuation of motor 92 will result in cylinder body 93 pushing motor 90, carriage 76 and casing brake assembly 74 downstream from the stuffing horn approximately 1/4 inch so as to remove the sizing ring of casing brake 104, discussed in further detail below, from the stuffing horn (FIG. 7). 
     Assembly 74 comprises casing brake 104 and fluid motor 106 as drive means for adjusting the tension applied against the casing on the stuffing horn. Brake 104 includes an outer housing 108 (FIG. 6) with a lower mounting flange 78 for connecting with bolts 77 and 79 to platform 80 of carriage 76. Housing 108 is also equipped with an outer retaining plate 110 for sizing ring 132. A sleeve 112 mounted inside housing 108 has outer surface threads 114 for engaging with inner threaded collar 116 held in the interior of housing 108 by retaining pins 118. The backside of sleeve 112 includes a funnel shaped casing guide 120 to facilitate deshirring and throughput of empty casing through casing channel 121 from the stuffing horn during filling. Sleeve 112 is also equipped with arm 122 for linking to rod 124 of motor 106. Fluid motor 106 is anchored to platform 80 through connector 126 (FIG. 4). Introduction of fluid via lines 128 and 130 will extend or retract rod 124 and rotate sleeve 112 through arm 122 moving it axially along the shaft of the stuffing horn. Accordingly, sleeve 112 performs as a compression ring for resilient sizing ring 132. That is, extension of rod 124 will turn sleeve 112 clockwise, or counterclockwise when retracted, increasing or decreasing the pressure exerted on sizing ring 132. Because of the inner angular slant of the sizing ring, including inner ring retainer 134 and outer retaining plate 110 rotation of threaded sleeve 112 will increase or decrease the compressive force being applied on the sizing ring and the empty casing by the sizing ring lip 136 during stuffing operations. Thus, the diameter of a sausage in the course of filling can be adjusted, for example, if oversized by turning sleeve 112 clockwise to lessen the pressure being applied to empty casing being drawn from the horn. 
     As previously mentioned, sizing ring 132 during the stuffing cycle controls the diameter of the filled product by regulating the rate of release of unfilled casing from the stuffing horn whereby sizing ring lip 136 compresses empty casing against the shaft of the horn. As part of the closing cycle, after completion of the filling cycle, actuation of dual clipper mechanisms for gathering the trailing and leading ends of filled and unfilled casing and applying end-closure clips thereto, the casing brake assembly 74 is advanced downstream by actuation of fluid motor 92. More specifically, through this action casing brake 104 is moved axially a short distance to remove sizing ring 132 off the shaft of the horn. Because of the compressive action of threaded sleeve 112 the sizing ring lip 136 forms a flange 138 (FIG. 7) circumferentially about outlet 140 of the stuffing horn. Flange 138 not only performs as a flap valve to prevent the backflow of meat emulsion over the horn exterior during the closing cycle, but also assists in forming filled casing with substantially flat ends (FIG. 1) for greater product yield. 
     The product closing section 34 (FIG. 5) is comprised of adjacent dual clipper mechanisms 142 (FIGS. 5 and 8) mounted on a clipper carriage 144 (FIGS. 4 and 5) for translation along the axis of the stuffing horn. Clipper carriage 144 is comprised of a rectangular shaped platform 146 formed from multiple welded support members 147. Opposing side support members 147 have aligned openings 149 lined with bushings 148 also for movement on rails 82 and 84. Platform 146 includes parallel vertical supports 150, 152 (FIG. 4), and mounting plate 154 for first and second adjacent clippers 156 and 158 (FIGS. 5 and 8). 
     First clipper 156 is a chub clipper which compresses the trailing end of a filled casing, gathers the casing of the compressed end and applies an end-closure clip thereto. The second clipper 158, which is adjacent to, but spaced slightly from the first clipper 156, gathers the attached leading end of unfilled casing and applies an end closure clip thereby preparing the next adjacent casing for stuffing. The clippers are essentially identical devices with each having a clip punch mechansim comprising fluid motor 160 and 162 (FIG. 5), a magazine 164 and 166 for automatically feeding clips of conventional design, a punch rod 168, 170 (FIG. 12) and a die member 172, 174 against which the punch rod compresses and closes trailing end clip 176 of a filled casing and leading end clip 178 of the unfilled casing. 
     A knife 180 (FIGS. 8 and 12) is disposed between first and second clippers 156 and 158 for severing casing between the trailing and leading end clips 176 and 178. Knife 180 is driven by fluid motor 182 (FIG. 8) having fluid lines 186 and 187. Fluid motor 182 may be affixed to the first or second clipper, for example, through motor mount 188, the latter of which is welded to die gate 190 (FIGS. 8 and 12). 
     Clippers 156 and 158 each have a die gate 190 and 192 (FIGS. 8 and 12) for supporting dies 172 and 174. In addition, the clippers have spaced opposing gate members 194 and 196 which are offset in a parallel plane and swingable in an interleafed arrangement, as best illustrated by FIGS. 8 and 12. Such clipper devices are available from Tipper Tie, Inc., Apex, N.C., such as Model Z4141. Because of the dimensions of fluid motors 160, 162 to assemble the first and second clipper devices adjacent to one another, the alignment of the devices is offset, as best illustrated by FIG. 8, so that the fluid motors are not directly next to one another. 
     Clipper carriage 144 is axially moveable on rails 82 and 84 and is driven by a fluid motor 198 which is affixed to cross support 42. Fluid motor 198 comprises fluid lines 202, 204 and rod 206 engaged to support member 147 of the clipper carriage through rod connector 208. Fluid motor 200 comprising fluid lines 210, 212 and rod 214 interacts with motor 198 limiting the return throw of rod 206. That is to say, motor 200 performs as a piston stop limiting the return of the piston (not shown) and rod 206 of motor 198. During the stuffing cycle clipper carriage 144 and rod 206 of motor 198 are fully extended upstream placing the dual clipper mechanism 142 over casing brake 104. During the closing cycle the clipper mechanism 142 is withdrawn from casing brake 104 in a downstream direction. Rod 214 extending into the backside of motor 198 restricts the downstream return of piston and rod 206, so that clipper mechanism 142 is adjacent but in front of casing brake 104. However, in order to load a new strand of casing onto the stuffing horn, the horn must be free to pivot sideways. In other words, in addition to actuating fluid motor 90 for moving carriage 76 and casing brake assembly 74 downstream to make clearance for pivoting the stuffing horn to loading position, dual clipper mechanisms 142 must also be moved downstream. Accordingly, motor 200 is actuated to withdraw the piston stopping action of rod 214 downstream followed by actuating motor 198. Rod 206, clipper carriage 144 and dual clippers 142 are able to be withdrawn to their fullest potential permitting clearance of the stuffing horn to loading position. 
     The product receiving and discharge section 36, best illustrated in FIGS. 4, 5, and 9, provides support for the stuffed food product during the filling and closing cycles and delivers the product from the apparatus for further processing i.e. cooking, etc. Receiving and discharge section 36 includes a table 214 and table extension 216 (FIGS. 4 and 5). Table 214 is supported by leg members 218 and 220. Each leg has a threaded leg screw 222 engaged to the bottom side of table 214 through connecting hinges 224 (FIG. 5) and to frame members 40 and 42. Adjustments are made in the height of table 214 by turning height adjusters 226. 
     Table extension 216 is engaged to both table 214 and clipper carriage 144 (FIG. 5). Table extension 216 includes a product receiving platform 228, a vertical tongue-and-groove support assembly 230, a horizontal connecting rod 232 engaged with the tongue-and-groove assembly 230 and a sleeve 234 for rod 232 to slide. Stationary groove 231 of tongue-and-groove 230 is affixed to support member 147 of clipper carriage 144. When the clipper carriage 144 is moved upstream or downstream of the stuffing horn, rod 232 and product receiving platform 228 will move horizontally with the carriage. Likewise, when table 214 is raised or lowered the slidable tongue in the stationary groove will permit raising and lowering of platform 228. 
     Table 214 (FIGS. 4 and 9) includes spaced parallel sidewalls 236 and 238 flared outwardly at their upper ends. Table base 240 joins the lower edges of sidewalls 236 and 238. Multiple spaced cradle rollers 242 are joined to the parallel ends of sidewalls 236 and 238 to provide a slideable bed for the food product as it is stuffed out. 
     Product receiving and discharge section 36 also includes controls for limiting the size of the product being stuffed. In this regard, during the stuffing cycle when the stuffed product reaches a predetermined length, the leading end of the product engages length limiting switch 244 (FIGS. 4, 5, and 9) mounted on sidewall 238 (or sidewall 236) of table 214 through mounting flange 246 and fastened by screw member 248. The switch can be mounted at any location along the table depending upon the desired length of the final product. The leading end of stuffed casing engages product contact 250 of switch 244 causing the circuit to open by rotation of shaft 252 terminating operation of the meat pump and further flow of emulsion into the casing. Spaced trailing end and leading end clips 176 and 178 are installed on the trailing end of the filled casing and the leading end of the adjoining unfilled casing and the casing between the two clips severed by means of knife 180. The filled product now on table 214 can be discharged by actuating fluid motor 254 (FIGS. 5 and 9) via fluid lines 255, 256 to extend rod 258 affixed to table base 240 through rod connector 259. For added flexibility and convenience rod 258 can be affixed to connector 260 on the opposite side of base 240 to dump product on the opposite side of table 214. Fluid motor 254 is connected to threaded leg screw 222 through motor mount 262 (FIGS. 5 and 9) and guide rod 263 so that the motor will always be positioned at the proper height for dumping a filled and clipped product. 
     The operating sequences of the apparatus are initiated by depressing switches in control box 165 elevated by vertical and horizontal supports 169 and 171. The sequences are best demonstrated by FIGS. 10-12 wherein FIG. 10 illustrates the stuffing cycle with a casing 264, having a leading end-closure clip 178, being filled with a pressurized meat emulsion 265. During the stuffing cycle the first/chub clipper 156 for closing the trailing end of casing 264 is moved upstream along with horn clipper 158 so they are aligned over casing brake 104 (FIG. 10). Lip 136 of sizing ring 132 compresses the unfilled, deshirred casing against stuffing horn 50. The pressure applied by the sizing ring and regulation of product diameter is controlled by sleeve 112 and fluid motor 106. To increase product diameter during the stuffing cycle, the pressure exerted is increased by extending rod 124 and turning sleeve 112 clockwise, or counterclockwise by retracting rod 124 in order to decrease product diameter. 
     As shown by FIG. 11, at the conclusion of the stuffing cycle chub clipper 156 is moved upstream in front of the stuffing horn 50, and casing brake 104 is advanced upstream sufficiently to remove sizing ring 132 from the horn. A programmable controller 266 (FIG. 5) provides the means for regulating intervals for actuating casing brake carriage 76 and clipper carriage 144, including the timing for activation of the individual clippers. More specifically, programmable controller or microprocessor 266 regulates the time interval for first actuating motor 198 retracting chub clipper 156 downstream off of casing brake 104 positioning it in front of the stuffing horn and applying clip 176 to the trailing end of the filled sausage 268. After movement of the chub clipper, sizing ring 132 is advanced downstream after completion of the programmed delay. That is, at a preset time the microprocessor shifts the sizing ring off of the stuffing horn to release additional unfilled casing. 
     The time delay for activating the casing brake carriage 76 for removing the sizing ring from the horn is regulated according to the physical properties of the food product. Generally, in the case of a nonviscous food material having relatively fast flow characteristics the sizing ring will be removed from the horn to release additional casing substantially simultaneously with actuation of the chub clipper, in order to form a trailing terminal end which is virtually flat. Furthermore, as the viscosity of the food material increases, the time delay in removing the sizing ring from the horn is increased, so with thicker more viscous food products the time delay for removing the sizing ring is also increased proportionately. Accordingly, needed adjustments in timing a particular sequence of activities for a given stuffing operation depending on the flow characteristics can be made by programming controller 266. Exact intervals between actuation of the chub clipper and removal of the sizing ring can be determined through exercise of ordinary skill. 
     Subsequent to the installation of chub clip 176, the closing cycle sequence includes applying a spaced end-closure clip 178 to the leading end of the adjoining unfilled casing. Motor 198 is activated to retract clipper carriage 144 upstream to move both the trailing end of filled and clipped casing 268 with the chub clipper 156 and horn clipper 158 approximately one inch in front of the outlet of the horn. This will assure that the leading end of the unfilled casing will also have a substantially flat end. After clipper 158 is activated and horn clip 178 has been applied to the leading end of the unfilled casing, the casing between clips 176 and 178 is severed by actuating knife 180. Filled casing 268 is then discharged from dump table 214 by actuating motor 254. 
     Although the invention has been described in considerable detail with respect to the preferred embodiments thereof, it will be apparent that the invention is capable of numerous modifications and variations to those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Apparatus and methods for stuffing food casing to produce sausage products with a high degree of dimensional uniformity for prepackaging applications. Substantially flat terminal end portions for higher product yields are prepared by a stuffing sequence which includes application of end-closure clips while regulating the interval for releasing unfilled casing. The delay sequence in the release of unfilled casing from the stuffing horn is directly proportional to the viscosity of the meat emulsion at the time of stuffing.