US2382504A - Method and apparatus for forming tubular casings - Google Patents

Description

K. scHuL-Tz Aug. 14, 1945.

METHOD AND APPARATUS FOR FORMING TUBULAR CASINGS Filed June 5 1941 v INVENTOR. jfmZZazz JZ/ZQZZZ,

mm a ms R Q Q a Patented Aug. 14, 1945 METHOD AND APPARATUS FOR FORMING TUBULAR CASINGS Kristian Schultz, Chicago, Ill., assignor to Armour and Company, Chicago, 111., a corporation of Illinois Application June 5, 1941, Serial No. 396,733

3 Claims.

This invention relates to a method and apparatus for forming tubular casings, and more particularly for forming plastic material into casings wherein the fibers of the material are disposed obliquely within the wall of the casing to strengthen the same.

In the manufacture of casings from animal sources, as well as from fibrous material, a great disadvantage has been encountered in the tendency of the fibers to form in a manner causing the finished casing to readily tear or split along weakened lines.

An object of the present invention is to provide apparatus wherein the casing which is passed through a forming chamber under pressure is operated upon by a specific mechanism to dispose the fibers in a direction which will tend to keep them from splitting when subjected to transverse stresses. Other specific objects and advantages will appear as the specification proceeds.

The invention will more clearly appear from the following specification and drawing, in which is shown a longitudinal sectional view of the apparatus with a portion of the apparatus shown in elevation.

Any suitable material may be treated in the apparatus. For example, a plastic material formed of treated sinews, hides, tendons, and other materials from animal sources may be employed. For example, if animal tendons are used, they may be dried, hammered, shredded, and card'ed, and then mixed with water and glycerin. This mass may be mixed with acid and kneaded into a highly plastic mass,

The material is then passed under high pressure from a suitable source (not shown) into the apparatus which will be described for the forming of the casing.

In the specific embodiment of my invention described herein, the apparatus is providedwith a base I which supports vertical standards IL and I2. The standards I l and I2 are joined by cross members l3 and l4. 0

A casing I5 is secured to the standard II by bolts, such as the bolts l6, disposed around the periphery of the casing and threadedly engaging the standard II. A casing I1 is similarly secured to the opposite side of the standard II by bolts such as the bolt l8. The standard l2 supports the casings or mountings l3 and which are secured to the standard by bolt 2| and pin 22 or any other suitable means.

The casings l5, l1, l9 and 20 are equipped with central openings arranged in register with each other and receiving the tubes and shafts of the apparatus. The elongated tube 23 is received Within the casings l5, l1 and I9 and rotatably supported by these casings. Near the central portion thereof, the tube 23 is provided with a reduced. portion 21 which receives and supports the pulley wheel 24, the wheel being attached to the tube by the key 25. The central opening in the pulley wheel is only slightly greater in diameter than the reduced portion 21 of the shaft so that when the wheel is urged toward the enlarged portion of the shaft it engages the annular fiange 26. Adjacent the reduced portion 21 of the tube 23 and near the casing 19 the tube 23 is provided with a further reduced portion 28 which is snugly received within the bearing surface 29 of the casing l9.

At its opposite end the tube 23 is cut away to provide a portion 30 of reduced diameter. This portion 30 is provided with a plurality of independent threads 3| extending around the same and projecting therefrom toward the casing l5. Preferably the outer peripheries of the threads 3| are very close to the inner wall 32 of the easing IS.

The casings I1 and I9 are provided with cut away portions 33 and 34'respectively which prevent contact between the tube 23 and the inner wall of these casings throughout the cut away portion, thereby reducing friction between the tube 23 and the casings. Passages 35 and 36 leading to these cut away portions are equipped with grease fittings 31 and 38 respectively. An annular ring 39 is disposed about the tube 23 immediately adjacent the portion 30 and engages on one side the standard II and on its outer periphery the casing IS. The other side of this ring 39 receives packing material 40 which seals the central opening of the casing [5 about the tube 23.

Within the tube 23 is a shaft 4| which is fixed to the casing 20 by the key 42. The shaft 4| fits snugly within the tube 23 and permits rotation of the tube about the shaft. One end of the shaft 4| extends through the casing 20 and is provided with a threaded portion 43 which receives a nut 44. The other end of the shaft 41 is provided with an enlarged extension 45 which is disposed within and spaced from the central opening in the casing IS, the outer wall of the portion 45being spaced from the inner wall of the casing l5 by a distance approximately equal to' the thickness of the sausage casing to be formed. The end 46 of the enlarged portion 45 adjacent the tube 23 is beveled.

The shaft 4| is provided with a central annular recess 41 which prevents engagement of this portion of the shaft with the tube 23. Passages 48 and 49 communicate with the cut away portions 33 and 34 respectively and permit the introduction of lubricants into the recess 41.

Adjacent the pulley wheel 24 and engaging one side thereof is a bearing member 50 which is arranged between the pulley wheel and the nut 5|. A lock nut 52 is placed on the other side of the nut ii. The nuts 5| and 52 are" both mounted on the casing Hi. When the nuts Bl and 32 are moved along the casing l3 toward the bearing member II the pulley wheel 24 is urged toward the casing ll. This movement of the pulley wheel 24 brings the side of the pulley wheel into engagement with the flange 23 on the tube 23 and tends to move the tube 23 in the casings.

The casing i3 is provided with an annular passage 33 adjacent the portion 33 of the tube 23. The passage 53 communicates with a passage 34 which in turn receives an inlet tube 55 through which plastic material may be introduced into the forming chamber.

The inner wall 32 of the central opening in the casing it provides, together with the portion 33 of the tube 23, a tubular forming chamber through which the plastic material may be passed. The projecting threads 3| extend from the wall 30 into the chamber to engage material passing therethrough.

In operation, the pulley wheel 24 is driven by any suitable power means to cause rotation ofv the tube 2: within the casings l5, l1 and Is. The plastic material is introduced into .the apparatus through the inlet tube 55 and the passages 54 and 53. From the passage 53 the plastic material passes through the forming chamber provided by the inner wall 32 of the casing I and the wall 30 of the tube 23. The rotation of the tube 23 causes the threads 3| to rotate in engagement with the material in the forming chamber. The threads extend into the material and frictionally engage not only the material adjacent the inner wall of the chamber but also the central portion of the layer of material in the chamber. This motion of the engaging threads causes a large portion of the fibers to be disposed obliquely with respect to the axis of the casing and the forming chamber. From the forming chamber the material passes into the discharge passage 56 provided by the inner wall 32 of the casing l5 and the outer surface of the extension 45 of the shaft 4|.

The tube 23 may be rotated in either direction. However. it is preferable to rotate the tube 23 so that the threads 3| tend to urge the material passing through the formin chamber towards the passage 53. In other words, it is preferred to rotate the tube 23 in a counter-clockwise direction when viewed from the discharge passage. When the tube 23 is rotated in this direction it produces a more effective rearrangement of the fibers and an interlocking of the same.

The quantity of plastic material which is introduced into the forming chamber may be controlled by adjusting the size of the passage 53. One side of this passage is provided by the tube 23 which may be adjusted longitudinally by moving the nuts 5| and 52. Such adjustment of the longitudinal position of the tube 23 provides an adjustment of thesize of the passage 33. The longitudinal position of the shaft 4| and the enlarged extension 45 may also be adjusted by tightening or loosening the nut 44.

By referring herein to the action upon the plastic material in the forming chamber, I mean to include any frictional engagement with the material, while it is forced through the apparatus under pressure, which produces a rearrangement of the fibers and disposes them. particularly the fibers in the central portion of the casing wall, in oblique relation with respect to the axis of the forming chamber and casingl The member 33 is shown provided with a double screw. Multiplethreads are apparentlymoreefleetive in operation than a single thread. It will be understood that any number of spiral threads may be used.

While there are shown and described certain embodiments of the invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims.

I claim:

1. In apparatus for forming tubular casings from fibrous plastic material, a tubular chamber, a member rotatably mounted within said chamber with its walls spaced from the inner wall of the chamber to provide a tubular space therebetween, projecting threads on the outer wall of said member, an inlet in said chamber communicating with the space between said walls for introducing fibrous plastic material under heavy pressure into said space to form a tubular casing therein, means for rotating the thread-equipped member in a direction in which the threads engage and tend to move the plastic material in a direction opposite to the direction of movement of the material in the chamber, said engagement of the threads with the plastic material serving to give direction to the fibers in the casing, and an outlet in said chamber for withdrawing said material from the chamber in the form of a casing.

2. A method of forming tubular casings from fibrous plastic material, comprising forming a plastic mass of said material into a tubular body in a forming zone, successively subjecting difi'erent portions of the tubular wall of said body to radial compression and arcuate frictional action about the axis of the body to knead the wall of said body throughout substantially the entire thickness thereof, said body being maintained in tubular form throughout the kneading operation, the plane of the arc in which said frictional action is exerted being substantially transverse to said axis whereby the fibers of said wall are aligned transversely with respect to said axis, simultaneously exerting fluid pressure on one end of the mass to cause the same to flow longitudinally along said axis into a dicharge zone, and forming the mass in the discharge zone into a tubular casing having smooth inner and outer surfaces and providing a tubular wall of substantially uniform thickness.

3. A method of forming tubular casings from fibrous plastic material, comprising forming a plastic mass of said material into a tubular body in a forming zone, successively subjecting different portions of the tubular wall of said body to radial compression and arcuate frictional action about the axis of the body to knead the wall of the body throughout substantially the entire thickness thereof, said kneading operation being continued until substantially all portions of the wall have been subjected thereto, said body being maintained in tubular form throughout the kneading operation, simultaneously exerting pressure on one end of the mass to cause the same to flow longitudinally along said axis, passing the KRIB'I'IAN SCHULTZ.

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