US 2919990 A
Description (OCR text may contain errors)
Jan. 5, 1960 H. e. PODLESAK ETA!- 2,919,990
METHOD CONTINUOUSLY PRODUCING PACKAGED UNITS Filed June 22, 1955 v s SheetsP-Sh'e'et 1 Q give/$125": 05 v j azvggal oaleaaifi 3 Sheets-Shegt 2 H. G. PODLESAK METHOD OF commuousm PRODUCING PACKAGED UNITS Filed June 22, 1955 Jan. 5, 1960 3 Sheets-Sheet 3 I H. G. PODLESAK EI'AL METHOD OF CONTINUOUSLY PRODUdI NG PACKAGED unn's Filed June 22, 1955 WR MW Jan. 5, 1960 United States Patent NIETHOD 0F CONTINUOUSLY PRODUCING PACKAGED UNITS Harry G. Podlesalk, Winnetka, George Howard Kraft, Wilmette, and Roland E. Miller, Orangeville, 11]., assignors to National Dairy Products Corporation, a corporation of Delaware Application June 22, 1955, Serial No. 517,218 6 Claims. (Cl. 99-178) The present invention relates generally to improvements in the art or" packaging and more particularly to an improved method and apparatus for wrapping an article in a scalable, flexible sheet material. The present invention has particular application to the packaging of food products and the like, which are susceptible to mold growth and in packaging such products the sheet materials used, in addition to being flexible and scalable are usually substantially gas and moisture impermeable.
Various flexible sheet materials, plastic films, coated foils etc., havebeen used in packaging for several reasons. First, they provide an inexpensive, substantially air-tight package which will maintain perishable items in a state of freshness for a relatively long period of time. Second, the materials provide a highly attractive package and in the case of many of the plastic film materials, a transparent package is provided which enables the consumer to view the product within the package.
In the case of food products, as for example, cheese, it has been possible to produce satisfactory packages on automatic or semi-automatic packaging equipment so long as the unit to be packaged was of a regular shape. However, when the shape of the unit is not regular, it is difficult to obtain a satisfactory machine-made package which will maintain such a product in a fresh or moldfree condition for commercial purposes for the desired period of time. In the main, this has resulted from the fact that when a unit of regular shape is packaged, the wrapper can be drawn taut to eliminate air, but irregularities in the shape of the packaged unit provide pockets in the finished package which retain air whose oxygen content promotes mold growth and other deterioration.
This problem of entrapped air is particularly serious in the packaging of random-size cuts of cheese or slices of cheese which have been cut from a block by mechanical slicing equipment. In packaging this type of cheese, it has been found desirable to reduce the air or oxygen level by packaging such cheese in suitable Wrappers, drawing all possible air out of the unit with vacuum and then sealing the package. This procedure has met with some success, but the process is extremely expensive because it usually requires better than average wrappers and is ordinarily carried out on individual packages as a batch operation. 7
The principal object of the present invention is the provision of an improved method for semi-automatically or automatically wrapping units in flexible sheet material. Another object of the invention is the provision of a method for packaging irregularly shaped objects in such a manner that oxygen retention in voids and pockets is substantially eliminated. A more specific object is the provision of a method for automatically or semi-automatically wrapping cheese units or the like, in such a way that mold growth is minimized.
Other objects and advantages of the inventionwill "ice become known by reference to the following description and the accompanying drawings:
In the drawings:
Figure 1 is a perspective view of the wrapping apparatus embodying various of the features of this invention;
Figure 2 is a side elevationalview partially in section, of the wrapping apparatus shown in Figure 1;
Figure 3 is a plan view of wrapping apparatus shown in the preceding figures;
Figure 4 is a sectional View along line 44 of Figure 3;
Figure 5 is a sectional view of the sealing and crimping rolls taken along line 55 of Figure 3;
Figure 6 is an enlarged plan view of the driven rollers shown in Figure 3; and
Figure 7 is an elevational view of the driven rollers taken along line 77 of Figure 6. The method of the invention generally includes disposing a series of the units to be packaged in spacedapart relationship in an open-ended tube of substantially flexible, scalable sheet material and in the event a food product is to be packaged, the material is desirably substantially gas and moisture impermeable. The air in the tube is then replaced with a suitable preservative atmosphere, after which the Walls of the tube are sealed together between the packaged units to divide the tube into substantially gas-tight sections. Each of the sections encloses at least one of the units and the sealed sections are cut apart to form individually packaged units..
It has been found expeditions to place the units to be packaged on a strip of the packaging material being used thereafter forming the sheet into a tube about the spacedapart units. The formation of the tube may be accomplished by folding the strip into a tube with a single longitudinal seam which may be heat sealed or otherwise sealed together or a second strip of packaging material may be placed over the units and sealed along its edges to the carrier strip to provide a two-piece tube.
It has been found that best results are obtained when the preservative gas is conducted into the tube in such manner that it fills a section of the tube which encloses a number of the spaced-apart units being packaged. The tube is then collapsed progressively to force the gas back through the tube to its point of formation. As the tube is collapsed the film from which the tube is fabricated is pressed into intimate contact with the surface of the units being packaged and then the walls of the collapsed tube may be sealed together to divide the tube into substantially gas-tight sections, each enclosing at least one of the units. The series of scaled sections may then be cut apart to form packaged units.
When employing the method'of this invention, the preservative gas is desirably conducted by suitable means such as, for example, a pipe or conduit, into the body of the tube a distance such that several of the units being packaged are disposed between the end of the pipe from which the gas is discharged and the open end of the tube. This manner of introducing gas into the tube in combination with the collapsing of the tube causes a diluting and a sweeping action which reduces the oxygen content or the content of any other undesired gas to a minimum. In the packaging of cheese, the preservative gas employed has been either nitrogen or carbon dioxide, however, carbon dioxide gas or mixture of carbon dioxide gas with other gases may be employed as well as other suitable non-mold-growth-sustaining gases. In one'commercial embodiment, where nitrogen was used as a diluent and sweeping gas, the cross section of the tube was approximately 4 inches by /2 inch. This gas is preferably introduced into the wrapping material tube, in the 3 case of a tube of the cross section referred to above, at a point from about 20 inches to about 30 inches from the point at which the tube is formed and in this space there should be at least two of the entubed units being packaged. In such an operation, the conditions are controlled so that the residual oxygen content in each package is less than about 1.5 percent by volume.
The use of this method of packaging makes possible preservation of cheese and other food products having an irregular shape with a minimum of difficulty, in the case of other materials which require a different preservative atmosphere as, for example, moist air, dry air, or an antiseptic atmosphere, it can be obtained in a similar manner to that in which the oxygen is replaced in the case of a cheese package.
Suitable apparatus which may be employed for carrying out a method in accordance with various of the features of the invention is shown in the drawings and is described in the following paragraphs. While the packaging machine shown in the drawings is specifically adapted for the packaging of cheese, it will be understood that the method and apparatus of the invention may be used in the packaging of other products with equal facility.
As will hereinafter become apparent, the packaging machine shown in the drawings includes, generally, an elongated platform 7 having means 9 at one end for supplying a strip 11 of flexible wrapping material which is adapted to be drawn across the platform by suitable means. The units to be wrapped, indicated as U in Figure 1, are placed in spaced-apart relationship on the sheet or strip 11 as it is drawn over an initial section 13 of the platform 7. A forming station 15 is provided at which point the units U to be packaged are enclosed in a tube 17 that is made at least in part by the strip of material 11.
In order to supply preservative gas to the tube 17 in the manner previously indicated, a pipe or conduit 19 is supported adjacent the forming station 15 which pipe 19 extends longitudinally into the tube 17 of wrapping material 11. The pipe 19 is connected by suitable means 21 to a source of preservative gas (not shown) which gas is thereby conducted into the tube 17 of wrapping material. The gas flows from the open end of the pipe 19 under a positive pressure and serves to dilute and sweep out the air in the wrapping material tube 17. The entubed units U in the illustrated structure, are then acted upon by resilient means 23 which is operable to collapse the wrapping material tube 17 and presses it into close contact with the entubed units U. The tube 17 is then acted upon by sealing and severing means 25 whereby it is severed and sealed transversely to form individual hermetically sealed packages, as shown at P in Figure 1.
Referring now more particularly to the drawings, the specific wrapping machine, illustrated, embodies various of the features of the invention and, as has been pointed out, is particularly adapted to the packaging of cheese. The illustrated machine includes a frame 27 of fabricated construction having a series of suitable support legs, longitudinal members, and cross pieces, which are suitably connected together. The upper, longitudinal members and their associated cross pieces support and in part constitute the elongated platform 7 upon which the various operations are carried out.
At one end of the platform 7, there is provided the means 9 for supplying the strip of wrapping material 11. As shown in Figures 1 and 2, the means 9 include a pair of generally vertically disposed support members 29 which are attached to the opposite sides of frame 27 and which at their upper ends provide a support for a roll 31 of the wrapping material. The roll 31 is supported upon a transverse shaft 33 which is keyed or otherwise attached to the roll 31, the shaft 33 being supported in a pair 4 of suitable bearings 35 fastened to members 29. Proper tension is maintained in the sheet 11 as it is drawn from the roll 31 by a friction brake assembly 37 which acts upon a pulley 39 attached to the shaft 33.
Various types of wrapping materials can be used on the machine such as for example, cellophane coated with a waxlike material such as the material sold under the trade name Parakote, rubber hydrochloride such as the material sold under the trade name Pliofilm, vinyl chloride-acetate sheets such as the material sold under the trade name Vinylite, vinylidene-vinyl chloride sheets such as the material sold under the trade name Saran, and various other scalable, flexible sheets as well as various laminated sheets embodying the foregoing or other materials.
If the wrapping material being used is supplied in rolls having an interleaf sheet, as is common in the case. of coated sheets to prevent the layers of sheet material from sticking together, a suitable means for rewinding the interleaf sheet is provided, such as a rewind means being shown in the drawings at 41.
The rewind means 4-1, illustrated includes a rewind shaft or core 43 which is supported in a pair of bearings 45 which in turn are attached to the lower ends of the members 29 in the illustrated manner. In order to provide a positive rewinding action, the shaft 43 is adapted to be power operated. in the illustrated structure, this is provided by connecting the shaft 43' to a suitable gear train 47, which gear train is operatively connected to a suitable source of power 49 by suitable means as shown.
As was pointed out, the strip of wrapping material 11 initially moves onto an open initial section 13 of the platform '7. This is accomplished by drawing the sheet 11 from the feed roll 31 and under an idler roll 51 so that the strip or sheet 11 may be drawn tautly across the surface of the section 13. The section 13, as shown in the drawings, is arranged immediately adjacent the wrapper supply means 9 and comprises a generally flat, smooth-surfaced table-like area 53 which includes a pair of longitudinally extending guide rails 55. The guide rails 55 are held in place by suitable supports and brackets 57 and are suitably spaced apart to maintain the cheese units U in alignment along the center of the strip of wrapping material 11. The cheese units U in the illustrated machine are adapted to be spaced apart manually by an operator but the feed to the machine can readily be made automatic by employing known devices.
In the illustrated apparatus, the sheet 11 on which the units U are disposed is adapted to be wrapped around the units U to provide the tube 17. This is accomplished by a forming station 15 which is positioned on the platform 7 closely adjacent the discharge end of the section 13. The forming station 15 includes a forming shoe 59 which is adapted to wrap the strip 11 about the units U and to provide a seam 61 which can be sealed together by a sealing means 63 which also constitutes a part of the forming station 15.
In order to insure that the strip 11 is held taut and flat over the section 13 and that the sheet does not wrinkle in its central section in the forming shoe 59, the strip 11 is carried downwardly over an idler roll 65 mounted for rotation at the discharge end of the section 13 from which point it passes around a roller 67. The roller 67 is rotatably mounted on a pair of swingably mounted arms 69. The arms 69 are pivotally supported on a pair of brackets 71 attached to the frame 27. After passing around the roller 67, the strip of wrapping material is guided upwardly and into the forming shoe 59. The purpose of the roller 67 is to effect a tensioning of the strip 11 and to this end the roller 67 is constructed in such manner and of such materials that its weight applies the proper degree of tension to the strip 11. Instead of the construction described, various other means could be employed to tension the strip, e.g., a spring biased roll or the like.
shown in the drawings, there is a minimum of free space between the idler roll 65 and the formingshoe 59 so that the cheese units U are carried by the strip 11 over the idler roll 65 and are immediately moved onto the strip 11 as it enters the forming shoe 59 from the roller 67. This enables the transfer of the unit U from one section of the strip to the other without disturbing the spaced relationship of the cheese units U.
The forming shoe 59 includes a base member 73 which is of substantially the same width as the units U to be packaged (Figure 3). It also includes a pair of opposed, flared members 75 which are provided with stationary folding wings 77 which are adapted to cause the wrapper strip 11 to be folded upwardly around the units U into a tube incident to its movement through the shoe 59. The tube 17 at this point has vertically upstanding portions which are in face-to-face relationship and which provide a longitudinal seam in the tube 17. At the discharge end of the flared mmebers 75, there is provided a narrow slit which is defined by a pair of closely spaced upstanding members 79 which hold the seam 61 in an upright position.
In order that the units being packaged are not displaced by the folding of the strips 11 about the units, there is provided a hold-down roller 81 which is rotatably supported on a bracket 83 which is in turn attached to a bridge member 85 which extends over the forming shoe 59. The distance between the hold down roller 81' and the base member 73 is such that the units being packaged are prevented from moving upwardly incident to the folding of the strip 11 into a tube. The roller 81 is preferably fabricated from a material which will not stick to the materials being handled and, in the case of cheese, the roller 81 is preferably fabricated from a plastic polytetna-fluoro-ethylene and sold under the trade name of Teflonf While the roller 81 which is shown is fixedly supported, it can be readily provided with spring biasing, however, if the roller is spring biased it should be provided with a limiting stop so as to prevent it from moving down to a point where it would interfere with the passage of cheese units U thereunder.
The vertical opposing edges of the sheet 11 which form the seam 61 immediately upon emerging from between the members '79 are passed through the sealing means 63. The sealing means 63 includes a pair of opposed sealing rolls 87 and 88 which are rotatable and biased together to apply pressure to the seam 61. The sealing rolls 87 and 88 rotate in opposite directions on a pair of vertical shafts 89 and are arranged in a horizontal position on either side of the forming station 15 so that their peripheries coincide at the center line immediately forward and above the forming shoe 5-9. In the illustrated embodiment of the invention, the sealing rolls are heated since the materials which are commonly used in the packaging of cheese are heat scalable. However, if an adhesive seal is to be employed, suitable sealing means for that type of material should be used. The sealing means 63 in any event should be operable to provide an air-tight, longitudinal seal along the seam 61.
After the strip 11 has been sealed in the form of the tube 17, it is moved along the platform 7 until the seam 61, which is in the vertical position, is engaged by a folding guide 93 which is operable in cooperation with a folding roller 91 to fold the seam 61 into a horizontal position so thatit lies fiat on top of the tube 17. The folding guide 93 is so arranged that the seam 61 is folded over the top of the guide 93 and the roller 91 is adapted to complete the fold. The folding roller 91 and the folding guide 93 are mounted on an arm 97 hingedly mounted on a bracket 99 supported on the platform 7. It will be noted that the rotatable axis for the roller 91 is at an angle to the line of movement of the seam 61 (see Figure 3) and this disposition of the roller provides a straightening and tightening action on the folded seam.
As previously pointed out, a preservative gas is conducted into the body of the tube 17 through a pipe or conduit 19. The pipe 19 is supported at one end on the bracket and the pipe 19 is positioned to extend downwardly to a point adjacent the forming shoe 59 and then longitudinally beneath the upstanding members 79 of forming shoe 59 and the sealing rollers 87 and 88 into the tube 17. The pipe 19 terminates at a point adjacent the folding roller 91 with an open end 101 which is adapted to release the gas into the body of the tube 17.
The preservative gas is conducted from a source of pressurized gas (not shown) into the pipe 19 by means of suitable fittings and conduits indicated as 103 in the drawings.
In operation, the gas serves to dilute the air and to sweep it from the tube 17 rearwardly towards the forming shoe 59, the excess air and gas mixture flowing out of the tube at its open end at its point of formation. In this manner the oxygen content at the forward end of the tube 17, the end adjacent the folding roller 91, may be substantially reduced or minimized. As illustrated in Figure 2 and by the dotted lines seen in Figure 3, the pipe 19 extends into the tube 17 a distance equal to the length of at least several of the resulting packages P to a point adjacent the folding roller 91, so as to achieve maximum sweeping of air from the tube 17 rearwardly towards the forming shoe 59. While the pipe 19 may be of a shorter length than illustrated, it is preferred that the length of the pipe within the tube 17 be at least greater than the length of the tube necessary to form one of the resulting packages P, in order to achieve efiicient sweeping of the air from the forwardmost section of the tube 17 which is to be formed into a package P.
Preferably, the pipe 19 is of flattened cross section, as shown in Figure 4, so that it rides smoothly on the upper surface of the cheese or other units being packaged and so that it does not increase the open space in the package any more than is necessary. In packaging a unit having a transverse width of about 4 inches and a height of about /2 to inch, we have found that satisfactory exterior dimensions for the pipe 19 are about inch wide and about inch thick, the pipe 19 being preferably made from a non-corrodable material.
In order to expel excess gas from the tube 17, the tube is collapsed and pressed about the cheese units U. This is accomplished by providing the wrapping machine With suitable resilient means 23 which are operable to press the tube walls into intimate contact with the units U. In the illustrated embodiment of the machine, the resilient means 23 comprise a pair of resilient rolls 105 and 106 which are positioned one above the other and which are arranged with their axes at right angles to the line of travel of the tube 17 The rolls 105 and 106 are positioned adjacent the folding roller 91 and are arranged to provide a nip which engages the tube 17 to effect its compression. In this connection, the rolls 105 and 106 are positioned so that the nip, caused by the engagement of the rolls and 1196 one with the other, is disposed to receive the tube 17.
Each of the rolls 1155 and 1 86 illustrated includes a core 103 which is disposed about and attached to a supporting shaft 110. The core 108 is covered with a concentrically arranged layer 104; of a resilient material such as sponge rubber or the like to effect compression of the tube 17 about the units U incident to their passage therebetween.
In the illustrated embodiment of the machine, the rolls 105 and 1116 are supported upon a pair of vertical members Which are attached to and which extend from the platform 7. Each of the members 107 are provided with two pairs of parallel, vertically disposed slots 109, each of which pairs is adapted to support a bearing bracket 111. The pairs of slots 109 are vertically arranged and the upper of the pairs is adapted to support a bearing bracket 111 for the upper roll 105, while the lower of said pairs is adapted to support a bearing bracket 111a for the lower roll 106. Each bearing bracket 111 and 111a supports a suitable bearing which is adapted to 'rotatably engage the roll shafts 114 As illustrated in the drawings (Figure 2), each of the bearing brackets 111 and 111a is supported in the slots res by four bolts 112, which prevent rotational movement of the brackets 111 and 111a but permit vertical adjustment of the brackets in their associated slots. This permits adjustment of the resilient rolls 1% and toward and away from each other to permit a variation in the amount of pressure which is applied to the units U being packaged, thereby causing the rolls to engage each other over a fiat area which is preferably wider and longer than the unit U being packaged. By making the area longer than the unit in the direction of its movement, the tube is squeezed together forwardly of the unit, thereby preventing puffing of the preceding packages. While the length of the flat area may be less than the length of the unit U, Wearing of the rolls may prevent the establishment of a seal against the pressure of the gas with the referred to pulling of the preceding packages resulting.
In addition to the slots 1G9 and the bolts 112, positioning of each of the bearing brackets 111 and 111a and their associated rolls is facilitated by means of an adjusting screw 114 which is threadably engaged in an associated bracket 115 on the members 1 37. These screws 114 bear on the bearing brackets 111 and 111a and are operable to elfect their adjustment.
Preferably, the softness of the resilient layer 104 and the pressure applied by the resilient rolls 19S and 1% to the units being packaged is such that substantially all of the entrapped gas in the tube 17 is expelled from the tube. We have found that when packaging units which measure approximately 4 inches in width by 8 inches in length by /2 inch in thickness that proper pressure is indicated when the rolls 1125 and 1% are pressed together in an amount such that they provide a flattened area having a length greater than the length of the unit U, i.e. the dimension of the unit U in the line of travel of the tube 17. Of course, the rolls and 1% should not be so hard that the unit U is deformed and they should be operable to press the walls the tube 17 intimately together forwardly of the in the area between the spaced apart units U being packaged.
After the excess gas has been removed from the tube 17, the collapsed tube 17 containing the cheese units U is pulled forward from the resilient rolls 1135 and 1% and any wrinkling of the tube 17 resulting from the preceding operations is substantially overcome by two pairs of driven rollers 117, 117a and 118, and 113a, the pairs of rollers being positioned along opposite edges. The rollers of each pair are in superposed relation of the tube. The lower rollers of each pair 117 and 118 extend under the tube 17, as shown in Figure 6, and the upper rollers 117a and 118a are shorter than the lower rollers 11? and 118 but extend across a portion of the tube it will be seen that the two pairs of driven rollers 117, 117a, 1 13 and 118a provide nips which are adapted to receive the edges of the tube 17 (Figs. 6 and 7). in order to provide the desired unwrinkling and pulling effect on the tube 17, the driven rollers 117, 117a, 11S and 118a are driven at a faster rate than the resilient rolls 1% and 106 and they extend partially across the path of the tube 17 and diverge in the direction of travel of the tube 17. Each of the rollers is supported on the platform 7 by suitable brackets 119 and shafts Lil. The rollers 117, 1 17a, 118 and 118a are driven by a suitable gear train 121 which is connected to the source of power 49.
The sealing and severing means 25 are operable to seal the tube 17 between each or" the enclosed units U and to cut the individually sealed units U apart to form separate packages P. he sealing and severing means 1S, in the illustrated embodiment, comprises a pair of sealing and cutting rolls 123 and 124 which are positioned one above the other with their axes at right angles to the line of travel of the collapsed tube 17 so that their nip is disposed on the same level as the advancing tube 17. Each of the sealing and cutting rolls 123 and 124 is generally cylindrical in shape, and incudes a raised portion 126 which extends the length of the roll. The raised portion 126 (Fig. 5) on each of the rolls 123 and 124 is equal in width to approximately one-quarter of the circumference of the rolls. The raised portion 126 on the lower roll 123 includes a knife 127 and a pair of crimping areas 129, one of which is disposed on either side of the knife 127. The crimping areas 129 are adapted to be heated by means of electrical heating elements (not shown) whose power requirements are supplied through a slip ring 131 (Fig. 3). The upper roll 124 includes an anvil 133 which is adapted to coact with the knife 127 on the lower roll 123 to cut the wrapper tube 17. A pair of crimping areas 135, one of which is disposed on either side of the anvil 133, are provided on the upper roll 124 to coact with the crimping areas 129 on the lower roll 123. Means are provided in the crimping area 135 on the upper roll 124 to apply pressure to the collapsed tube 17 so as to aid in effecting a seal and to effect the movement of the packages therebetween. In this connection, each of the crimping areas 135 on the upper roll 124 is provided with a groove 137 which is designed to receive and hold a strip 138 of compressible material such as rubber.
In the operation of the sealing and severing means 25, rolls 123 and 124 are rotated periodically in timed relation to the passage of the collapsed portion of the tube 17. In this manner, the raised portions of each roll 123 and 124 coincide with the collapsed portion of the tube 17 intermediate the units U and the tube 17 is subjected to heat and pressure between the entubed units U to form longitudinally spaced, transversely extending seals. At the same time, the knife 127 and the anvil 133 coact to cut the tube transversely. This action divides the tube 17 into a succession of individual, sealed packages P. After the passage of the collapsed portion of the tube 17 between the rolls 123 and 124, the raised portions 126 no longer coincide and there is adequate clearance for the passage of the next succeeding unit U to pass between the rolls 123 and 124 without pressure on the unit U.
The sealing and cutting rolls 124 are driven by a suitable gear train 139 and a cam 140 which is operably connected to the source of power 49. Of course, other methods of sealing and severing the tube 17 to form individual packages which are known to the art may be employed.
The wrapping machine is provided with a takeofi conveyor 142 for receiving the sealed and severed packages P from the sealing and cutting rolls 123 and 124. The conveyor means 142 is of conventional design and comprises an endless conveyor belt 144 supported upon a pair of pulleys 148 and 150. The upper run of the belt 144 is level with the surface of the platform 7. The upper run of the belt 144 travels along the surface of the platform 7 in the same direction of travel as the tube 17 and is adapted to receive and carry forward the packages P to a point where they may be removed from the conveyor by an operator or other means. Pulley 148 is operably connected to the source of power 49 and provides the conveyor belt with the necessary power.
All the operating parts of the machine are driven ."by a source of power 49 (Fig. 2) which is mounted on-a platform 151 extending transversely between the lower, longitudinal suports of the frame 27. The power source 49 includes a motor (not shown) which is connected'to a speed reducer 154. The'speed reducer 154 is provided with a short stub shaft 156 having a sprocket158ffixefi thereto. The sprocket 158 is connected to a 'maimdrive shaft 160'by a drive chain 162 and a sprocket 164. The main drive shaft 160 is suspended beneath the cross supports of the frame 27 and runs longitudinally of the t'nachine. The shaft 160 carries a pair of helical gears .166 and 168 and a bevel gear 170.
The bevel gear 170 supplies the interleaf rewind gear train 47 with necessary power through a connection with bevel gear 172 which is keyed to a cross shaft 174. The cross shaft 174 carries a pulley (not shown) which drives a' belt 175 connected to a pulley 177 operatively connected to the gear train 47.
The helical gear 168 drives the resilient roll 106 and the gear train 121 which drives the driven rollers 117, 117a, 118 and 118a. In this connection, the gear 168 meshes with a gear 176 on a. cross shaft 178 which furnishes the necessary power to the roll 106 and gear train through endless chain and sprocket arrangements 179 and 180, respectively.
The helical gear 166 is connected with a gear 181 which turns a shaft 182. The shaft 182 is connected by drive chains 184 and 184a to the gear train 139 which drives the sealing and severing means 25. The chain 184 also drives the conveyor belt 144 by means of a chain and sprocket drive 185 which is operable to rotate the belt pulley 148.
Timing of the machine and of the sealing and severing means 25 in particular may be readily accomplished by known mechanisms by causing the actuation of the sealing and severing means 25 in response to a given linear movement of the tube 17 which is effected by the engagement of the resilient rolls 105 and 106 and the driven rollers 117, 117a, 118 and 118a, with the tube 17 thereby drawing the Wrapping strip 11 and the tube 17 through the machine. Another means of actuating the sealing and severing means 25 may be accomplished by converting the sealing and cutting roll cam 140 to a solenoid controlled member which is in turn actuated by a photo electric cell. The cell may be responsive to the units U being packaged or to marks on the wrapping material strip 11.
In order to provide a central point for installing switches, temperature gauges for the sealing means 63 and the sealing and severing means 25, gas flow controls and the like, it is convenient to provide a control cabinet 186 which may be located, as illustrated, on the members 107.
In one commercial embodiment of the apparatus which has been described, it has been possible to package a substantial number of units of cheese slices per minute, which units measured approximately 4 inches in width by 8 inches in length by /2 inch in thickness. The pipe 19 extended into the longitudinally sealed tube about 32 inches beyond the point at which the longitudinal seal was effected. Tests have shown that when the unit U having the above mentioned dimensions contains normal Swiss cheese which has approximately 17 percent of its volume occupied by voids or eyes, the oxygen content in the package was reduced to below 1.5 percent which results in a package with extremely good shelf life.
Various features of the invention are set forth in the appended claims.
1. The method of continuously producing packaged units which comprises successively disposing a plurality of the units to be packaged in spaced-apart relationship in an elongated tube having a single open end and formed of substantially gas impervious, flexible sheet material, maintaining at all times a plurality of such units in said open ended tube, continuously introducing a preservative atmosphere into said open ended tube, and then progressively, from the non open end of said tube, collapsing said tube to reduce the volume thereof and sealing the walls of said tube together between said units to divide said tube into substantially gas-tight sections, each enclosing at least one of said units, the introduction of said preservative atmosphere and the collapsing of said tube being effective to cause a portion of said preservative 10 atmosphere to pass over a plurality'of units anclout of the open end of said tube.
2. The method of continuously producing packaged units which comprises successively disposing a plurality of the units to be packaged in spaced-apart relationship in an elongated tube having a single open end and formed of substantially gas impervious, flexible sheet material, maintaining at all times a plurality of such units in said tube, continuously introducing a preservative atmosphere into said tube, and then progressively, from the nonopen end of said tube, collapsing said tube to reduce the volume thereof, pressing said sheet material against said units being packaged, and sealing the walls of said tube together between said units to divide said tube into substantially gas-tight sections each enclosing at least one of said units, the introducing of said preservative atmosphere and the collapsing of said tube being effective to cause a portion of said preservative atmosphere to pass over a plurality of units and out of the open end of said tube.
3. The method of continuously producing packaged units which comprises successively disposing a plurality of the units to be packaged in spaced-apart relationship in an elongated tube having a single open end and formed of substantially gas impervious, flexible sheet material, maintaining at all times a plurality of such units in said tube, continuously introducing a preservative atmosphere into the open end of said tube and conducting it to a point inwardly of a plurality of such units disposed within said tube whereupon said atmosphere is released in said tube, and then progressively, from the non-open end of said tube, collapsing said tube to reduce the volume thereof, and sealing the walls of said tube together between said units to divide said tube into substantially gas-tight sections each enclosing at least one of said units, the introducing of said preservative atmosphere and the collapsing of said tube being effective to cause a portion of said preservative atmosphere to pass over a plurality of units and out of the open end of said tube.
4. The method of continuously producing packaged units which comprises successively disposing a plurality of the units to be packaged in spaced-apart relationship, continuously forming around said units to be packaged an elongated tube of substantially gas impervious, flexible sheet material having a single open end, continuously introducing a preservative atmosphere into the said tube and then progressively, from the non-open end of said tube, collapsing said tube to reduce the volume thereof, the collapsing of said tube taking place at a point spaced from the point of tube formation to accommodate therebetween the inclusion within said tube of a plurality of units being packaged, and sealing the walls of said tube together between said units to divide said tube into substantially gas-tight sections each enclosing at least one of said units, said preservative atmosphere being introduced into the open end of said tube and being conducted to and released into said tube at a point between the point of tube formation and the point of tube collapse so as to cause a portion of said preservative atmosphere to pass over a plurality of units and out of the open end of said tube.
5. The method of continuously producing packaged units which comprises successively disposing a plurality of the units to be packaged in spaced-apart relationship in an elongated tube having a single open end and formed of substantially gas impervious, flexible sheet material, continuously introducing a preservative gas into said tube and then progressively, from the non-open end of said tube, collapsing said tube to reduce the volume thereof, the collapsing of said tube taking place at a point spaced sufficiently from said tube open end to accommodate therebetween the inclusion within said tube of a plurality of units being packaged, pressing said sheet material against said units being packaged, and sealing the walls of said tube together between said units to divide said tube'into substantially gas-tight sections each enclosing at least one of said units, said preservative gas being introduced into the open end of said tube and being conducted into said tube to a point adjacent the point at which the sheet material is pressed against the units being packaged and releasing said gas at that point whereupon a portion of said preservative gas is caused to pass over a plurality of units and out of the open end of said tube.
6 The method of continuously producing packaged units of cheese which comprises successively disposing a plurality of the units to be packaged in spaced-apart relationship, continuously forming around said units to be packaged an elongated tube formed of substantially gas impervious, flexible sheet material having a single open end, continuously introducing into said tube a preservative gas selected from a group consisting of nitrogen, carbon dioxide and mixtures thereof, and then progressively, from the non-open end of said tube, collapsing said tube to reduce the volume thereof, the collapsing of said tube taking place at a point spaced sufiiciently from said tube open end to accommodate therebetween the inclusion within said tube of a plurality of units being packaged, pressing said sheet material against said units References Cited in the file of this patent UNITED STATES PATENTS 2,145,941 Maxfield Feb. 9, 1939 2,194,451 Soubier Mar. 19, 1940 2,276,282 Bindszus Mar. 17, 1942 2,340,260 Clunan Jan. 25, 1944 2,540,815 Eldredge Feb. 6, 1951 2,569,217 Bagdigian Sept. 25, 1951 2,600,216 Denison June 10, 1952 2,649,671 Bartelt Aug. '25, 1953 2,753,268 Ingle et al. July 3, 1956