Patent Publication Number: US-3877203-A

Title: Flat turret wrapping machine

Description:
C United States Patent 11 1 3,877,203  
 Anderson Apr. 15, 1975 FLAT TURRET WRAPPING MACHINE Primary Examiner-Travis S. McGehee Assistant Examiner-l-iorace M. Culver 751 tzAd W.Ad Wt 1 men or 2 5:? arson es Attorney, Agent, o Firm-Markva &amp; Smith [73] Assignee: Scandia Packaging Machinery [57] ABSTRACT Company chfon The apparatus includes means for providing an article [22] Fil d; Apr, 15, 1974 having a sheet of wrapping material draped therearound so that the ends of the sheet project outwardly [2]] Appl&#39; 46l083 from one side and along opposing edges of the article.  
  The draped article is moved along a path past a fold- [52] US. Cl 53/228; 53/379 g work station- The folding Work station includes [51 1111.131... B65b 11/16; B65b 49/08; B65b 49/14 means for folding one of the projecting ends of the [58] Field of Search 53/379, 229, 230, 234, Sheet rn h h other proj cting end in an over- 53/228, 232, 221, 224, 225, 382, 388 lapped relationship on one side of the article. The wrapping material is then sealed along the overlapped [56] References Ci d ends of the wrapper sheet. The specific embodiments UNITED STATES PATENTS include a particular lifting mechanism used at the fold- 53 379 X ing work station. When heat-scalable wrapping mate- 53229 X rial is used, a heating assembly is disposed at a heat 2l95222 3/1940 Nezmair 53/229 X sealing work station. A flat turret chain incorporating 310553490 9/1962 Anderson I: 1 53/234 x a plurality of Pockets for receiving the P g to be 3,224,166 12/1965 Johns et al 53/382 pp is used to move the draped articles along the path.  
 20 Claims, 13 Drawing Figures PATENTEUAPR 1 51975 4. LIE:  
 FLAT TURRET WRAPPING MACHINE BACKGROUND OF THE INVENTION This invention relates to the wrapping of packages with a sheet of wrapping material that has been draped there-around. This wrapping material is thin, flimsy material and may include such heat-scalable material as heat-scalable polypropylene, polyethylene and nitrocellulose coated plastic materials and the like.  
  When over wrapping articles it is desired to have a complete, regular seal over the entire package. When certain articles are wrapped, it is necessary to have large projecting ends extending from a draped article. There is difficulty in handling these larger sized ends because of the instability of the wrapping material itself. It is common practice in the prior art to fold and seal the projecting ends in one operation by a wiping operation. Such a prior art procedure is shown in US. Pat. No. 3,656,273.  
  In the prior art apparatus, the article is carried by a turret wheel and the heating mechanism is disposed along the circumferential path of the package. With larger projecting ends it is possible that heat-sealable material would come into contact with the heater mechanism before it is in position on the package. When this happens, the film itself becomes distorted due to the heat and the resultant folding and sealing operation produce an irregular package.  
 PURPOSE OF THE INVENTION The primary object of this invention is to produce a flat turret wrapping machine wherein the folding of the wrapping sheet may be accomplished in a flat plane.  
  Another object of the invention is to provide a folding and lifting mechanism cooperating with each other to produce a regular tucking and folding operation along one side of a package.  
  A further object of this invention is to provide an apparatus for wrapping an article in a thin, flimsy heatsealable wrapping material wherein the overlapping fold is made at a fold working station separate from the heating assembly disposed at a heat sealing work station.  
 SUMMARY OF THE INVENTION These objects and other advantages are accomplished by the apparatus as described herein. An article is draped with a wrapper sheet having ends projecting outwardly from one side and along opposing edges thereof. The draped article is moved along a path. Folding means is disposed adjacent the path at a folding work station. One of the projecting ends is first folded underneath the other projecting end in overlapping relationship on one side of the article. When the wrapping sheet is a heat-sealable material, the folding operation is conducted under cold conditions. The projecting ends of the wrapper sheet are heat-sealed at a heat sealing work station laterally displaced from the folding work station along the path of movement.  
  Another feature of the invention is directed to the lifting mechanism. A vacuum manifold has a vacuumholding surface against which the first projecting end of the wrapper sheet is held. The vacuum-holding surface is displaceable between a lifting position and a foldholding position. A vacuum plate includes the vacuumholding surface that has openings disposed therealong. The vacuum plate is pivotally mounted along one edge thereof and the openings are disposed at a location toward the outer edge of the vacuum plate. The vacuum manifold is fixedly mounted on the vacuum plate over the openings. A novel valve means is provided for controlling the suction in the manifold.  
  In a specific embodiment, the vacuum plate has openings disposed along its entire lengths and has a length sufficient to extend outwardly from opposite sides of the article. The manifold has a center section and two outer sections each of which is operatively associated with the openings in the vacuum plate. The valve means is used to control the suction in the outer manifold sections separately and independently from the center manifold sections under specific wrapping conditions.  
  Another feature of the invention is the pocket structure used on the turret chain which has at least one straight, flat section therealong. The flat turret chain conveyor mechanism provides a flat surface along which the wrapper sheet may be first folded. The folded wrapper sheet is moved to a heat-sealing station where a novel heating assembly is used to seal overlapping ends of a heat-sealable wrapper sheet.  
 BRIEF DESCRIPTION OF DRAWINGS Other objects of this invention will appear in the following description and appended claims, reference being made to the accompanying drawings forming a part of the specification wherein like reference characters designate corresponding parts in the several views.  
  FIG. 1 is a side fragmentary elevational view of an apparatus made in accordance with this invention,  
  FIG. 2 is an elevational fragmentary view partly in cross-section as viewed from the left hand side of the apparatus of FIG. 1,  
  FIG. 3 is a perspective view of a pocket section made in accordance with this invention,  
  FIG. 4 is a fragmentary cross-sectional view of a pocket section disposed on the chain in accordance with this invention,  
  FIG. 5 is a fragmentary cross-sectional view along line VV of FIG. 3,  
  FIG. 6 is a detailed elevational view of the folding mechanism made in accordance with this invention,  
  FIG. 7 is a perspective view of a vacuum manifold made in accordance with this invention,  
  FIG. 8 is a perspective view of another embodiment of a vacuum manifold made in accordance with this invention,  
  FIG. 9 is a perspective view of a vacuum control mechanism made in accordance with this invention,  
  FIG. 10 is, a bottom plan view of a vacuum plate made in accordance with this invention,  
  FIG. 11 is a perspective view of an article after folding in the folding work station,  
  FIG. 12 is a perspective view of a heating assembly made in accordance with this invention, and  
 FIG. 13 is a plan view of a folding element.  
 DESCRIPTION OF SPECIFIC EMBODIMENTS More specifically, referring to the drawings, the flat turret wrapping machine, generally designated 10, includes a plurality of pockets 11 mounted for movement past a folding work station and a heat sealing work station. Each pocket section 11 includes a carrier block 12, a stationary guide holder 13 and a floating guide holder 14. A trucker blade 15 is disposed between the guide holders 13 and 14 and fixed to the carrier block 12 via plate 16.  
  The stationary guide 13 is composed of nylon and is fixedly held in place on the carrier block 12 by bolts 17. The floating guide element 14 is also composed of nylon and is adjustably located on carrier block 12 by the bolts 18. The guide element 14 includes slots 19 through which the bolts 20 are disposed. See particularly the detail of FIG. 5. The floating guide holder 14 provides a floating gripping hold on the package P that is thrust in place adjacent the tucker blade 15.  
  Springs 21 are laterally displaced between the guide element 14 and the support member 22. The arrangement of the springs 21 eliminates any biasing or tilting of the floating guide 14 when the package P is thrust into the pocket section 11. The spring-loaded guide element l4 enables the pocket member to establish a uniform bite particularly on small size packages. A package stop member is disposed adjacent the tucker blade and limits the amount of travel the package P makes when thrust into the pocket section 11.  
  The carrier block 12 carries three rollers 23 which are adapted to roll within the channel runner 24. Two rollers contact a first side of the channel runner 24 and the third roller contacts the side opposing the first side of the channel runner 24. The channel runner 24 is mounted on the frame structure 25 of the wrapping machine.  
  In this specific embodiment, a pair of double conveyor chains 27 are attached to the bottom of the carrier block 12. The pins of each chain extend through the holes 26 located in the two chain connecting portions 12a. The closed loop chains 27 move around an idler sprocket members 28 and a drive sprocket 29. A stabilizing mechanism includes a pair of pivotally mounted wing elements 30 having a stabilizing surface 31. Each carrier block 12 has a seating bottom surface 32 and a stabilizing abutment surface 33. The stabilizing surface 31 of the wing elements 30 engage the abutment surface 33 when the chain 27 moves around the sprocket member 28 and 29. The sprocket members include a contoured nesting surface 34 which receives the shaped seating surface 32 of the carrier block 12. Thus, the pocket sections are stabilized as they change direction along a closed loop path having at least one straight section as shown in FIG. I.  
  As shown in this embodiment, ten pockets are disposed along an indexing chain 27. Each pocket section 11 is adjustable in at least one dimension of height and width to receive the desired size of package P. As the package size P changes, the floating guide holder 14 is adjusted on the package carrier block 12 to suit the particular package. The tucker blade 15, tucker mounting plate 16 and package stop 5 become change parts as certain package dimensions vary. The drive sprocket 29 is operated in a well known manner to cause each pocket to travel intermittently between each work station.  
  A folding mechanism is located at a folding work station along the path of travel for the draped article or package P. A first of the projecting end A of the wrapping sheet is lifted away from the package P and the second projecting end B is folded along the edge of the article underneath the first end. The overlapped portion may be sealed together in various ways. However, heat-scalable wrapping material may be used and sealed by a heating mechanism. A detail of the relationship between the lifting mechanism and the folding elements is shown in FIG. 6.  
  The lifting mechanism includes a vacuum manifold 35 attached to a vacuum plate 36 having a vacuum holding surface against which the first projecting end A is held while the second projecting end B of the wrapper sheet is folded as clearly shown in FIG. 6. The vacuum holding surface is displaced between a lifting position and a fold-holding position wherein the projecting end A is held against the top of the package P as it moves along the designated path. 1  
  The vacuum plate extends across one dimension of the package and has a length which may extend beyond opposing edges of the package. In the specific embodiment as shown, the vacuum plate 36 is pivotally mounted along one edge thereof and openings 37 are disposed therealong at a location toward the opposing outer edge of the vacuum plate. A detail of this relationship is shown in FIG. 10. The vacuum manifold 35 is fixedly mounted in the vacuum plate 36 over the openings 37.  
  Two different embodiments of the lifting mechanism are shown in FIGS. 7 and 8. In the embodiment of FIG. 8, a single source of suction is attached via the conduit 38 to draw a vacuum across the width of the vacuum plate 36. The length of the extensions 39 varies with the height of the package being wrapped. When the height of the package in this embodiment is under 2 inches, the extensions 39 are short. For this reason, the manifold 35 is designed with one channel or source of vacuum and a single series of holes. The vacuum suction created by the vacuum first lifts the projecting end A.  
 as shown. The tucker blade 40 folds the projecting end B against the top side of the package P. The folding bar 41 holds the wrapping sheet snugly against the side of the package P as it moves along the path. Once the flap B is folded as shown in FIG. 6, the vacuum plate 36 moves from the lifting position as shown to the foldholding position. The vacuum is maintained along the top surface of package P so that the wrap will be held tightly and pulled snugly around the package as it moves into the sealing station.  
  The vacuum on the vacuum manifold 35 is controlled by a vacuum cut-off valve as shown in FIG. 9. Valve 50 may be a commercially available Humphrey valve. A cam follower 51 moves over the cam surface 52 which rotates on shaft 53 located above the turret chain. Movement of the can follower 51 actuates the vacuum valve 50 in the manner shown. The valve 50 is normally open. Therefore, when vacuum is required, the lever arm on valve 50 is in its working position. The high portion on the cam 56 activates the vacuum and the low portion on cam 52 dumps the vacuum.  
  Another embodiment of the lifting mechanism is shown in FIG. 7. When the height of a package exceeds about two inches, the extensions 39 as shown in FIG. 11 become longer. In this instance, the vacuum manifold 49 is provided with three separate sections as shown in FIG. 10. Here a mask 54 is placed over the vacuum plate 36 to provide a center vacuum section 55 and two outer vacuum manifold sections 56.  
  A first cut-off valve controls the outer manifold sec-&#39; tions 56 and a second cut-off valve controls the suction on the center manifold section 55 as it passes over the film disposed against the side of the package P. The outer manifold sections 56 are used to maintain the extensions 39 in the same plane as the wrapper sheet ends A and B which are being sealed against the side of the package P. That is, the centerfold section 55 moves over the side of the article and the outer manifold sections 56 extend beyond the edges of the article.  
  The vacuum suction is drawn on the center manifold section via conduits 57 and the vacuum section is drawn on the outer manifold sections 56 via the conduits 58. All pivoting operations are conducted by cams and followers in a manner well known in the prior art.  
  The trailing fold-holding bar 41 supports the wrapper sheet at the corner of package P. The folder blade mechanism having folder blade 40 and folding blade 41 is a cam operated in a well known manner. This folding mechanism is made in accordance with the prior art.  
  Once the projecting ends A and B have been overlapped with respect to each other, each of the cut-off valves are operated independently with respect to each other. First, just before the package P begins to move from the folding station, the vacuum suction on the outer manifold sections 56 is turned off. This eliminates any pulling of the extensions 39 away from the overlap relationship. On the other hand, the vacuum suction in the center manifold section 55 is not cut off until after the package begins to move away from the folding work station. The film is thus pulled taut around the package without disturbing the outer edges of the film.  
  in this particular embodiment, the wrapping material is a heat scalable material and a heater assembly is disposed at the heat sealing work station located downstream from the folding work station. The heating assembly is effective to seal together the overlapping ends A and B of the wrapper sheet. In this embodiment, a spring biased heating element 42 extends across the width of the package P and is movable between a resting position and a sealing position. Various types of heat scalable thermoplastic materials may be used such as heat sealable cellophane, polypropylene, or wrapper material having a nitrocellulose coating disposed therealong. The folding mechanism and the heater assembly are mounted in a pivotally mounted head portion a.  
  The folding of the heat-scalable material is done in a cold condition so that the material is not subjected to shrinking due to the heat. When heat is applied to a heat scalable polypropylene that is unsupported, shrinkage of the material occurs. If the heat-sealable material is not intimately in contact with each other, a satisfactory seal is not available. Thus, in these larger packages, the sealing area is automatically limited through the use of the lifting device as shown in the em bodiment of FIG. 7. While the package size has been discussed in terms of about 2 inches in height, this limitation may change accordingly as the film and package specifications vary. Furthermore, such a shrinking would adversely affect the material in the folding area and cause the wrapper to be distorted.  
  Further, the flat turret chain conveyor having the movable pockets disposed therealong provides a flat surface on which the folding and sealing can be effected rather than on the chordal point contact that is provided in conjunction with a standard turret wheel assembly. That is, when a prior art turret wheel is used, the distance between the chord of the radius and the circumference gives trouble during the heat sealing operation. This problem has been eliminated through the use of the flat turret chain section as set forth in the instant application.  
  When the package comes to rest in the heat sealing station, the cam 43 should have just reached its maximum stroke. Both cam 43 and the indexing chain conveyor dwell for Therefore, as the package P begins to move after sealing, the heater 4 2 begins to rise from the package P. The heating element 42 is heated via the heater block 44 which is biased by springs 45 against the top surface of the package being wrapped.  
  Slots 46 in the bracket 47 allow the position of the heater 42 to be adjusted with respect to the package being sealed. The bracket 48 is also adjustable in a vertical position to adjust the sealing pressure on the package P. The sealing pressure is provided by the springs 45. The sealing of the package depends upon the package specifications, film specifications, temperature,  
 time and pressure required and this is deemed to be within the skill of the artisan.  
  While the flat turret wrapping machine has been shown and described in detail, it is obvious that this invention is not to be considered as being limited to the exact form disclosed, and that changes in detail and construction may be made therein within the scope of the invention, without departing form the spirit thereof.  
  Having thus set forth and disclosed the nature of this invention, what is claimed is:  
 1. An apparatus for wrapping an article comprising:  
 a. means providing an article having a sheet of wrapping material draped therearound so that the ends of the sheet project outwardly from one side and along opposingedges of the article,  
 b. means for moving the draped article along a path to a stationary folding work station,  
 c. means for folding one of the projecting ends underneath the other projecting end in overlapping relationship along said one side of the article which is maintained stationary in said folding work station,  
 d. said folding means being located at said folding work station along said path, 7 i  
 e. said folding means including a liftingmechanism for lifting a first of the projecting ends away from the article and a folding element that folds the second projecting end along the edge of the article underneath said first end,  
 f. means for sealing the wrapping material along the overlapped ends of the wrapping sheet.  
 2. An apparatus as defined in claim 1 wherein said lifting mechanism includes a vacuum manifold having a vacuum holding surface against which the first projecting end is held and means for displacing the vacuum holding surface between a lifting position and a fold holding position.  
 3. An apparatus as defined in claim 1 wherein said lifting mechanism includes a vacuum manifold and a vacuum plate having openings disposed along a vacuum holding surface.  
 4. An apparatus as defined in claim 3 wherein the vacuum plate is pivotally mounted along the edge thereof and the openings are disposed at a location toward the opposing outer edge of the vacuum plate,  
 said vacuum manifold is fixedly mounted on the vacuum plate over said openings.  
 5. An apparatus as defined in claim 3 wherein the vacuum plate has openings disposed along its length and a length sufficient to extend outwardly from opposite sides of the article,  
 the manifold has a center section and two outer end sections, and  
 each manifold section is operatively associated with openings in the vacuum plate.  
 6. An apparatus as defined in claim wherein the center manifold section moves over the side of the article and the outer manifold sections extend beyond the edges of the article.  
 7. An apparatus as defined in claim 1 wherein said lifting mechanism includes a vacuum plate having openings, a vacuum manifold operatively associated with said openings, valve means controlling the suction in the manifold and means for intermittently operating the valve means.  
 8. An apparatus as defined in claim 7 wherein said manifold has a center section and two outer end sections,  
 said valve means includes a first cut-off valve for controlling the suction on the outer manifold sections and a second cut-off valve for controlling the suction on the center manifold section.  
 9. An apparatus as defined in claim 7 wherein said valve operating includes a cam means and a follower which actuates said valve means.  
 10. An apparatus as defined in claim 1 wherein the article moving means includes a pair of endless closed loop chains and a plurality of pocket means disposed along the length of the chains,  
 each pocket means includes a pair of pocket sections each of which is mounted on the chains for receiving an article therebetween,  
 each pocket section has a carrier block carrying a pair of guide holders and a tucker blade.  
 11. An apparatus as defined in claim 10 wherein the guide holders are adjustably disposed with respect to each other along the carrier block.  
 12. An apparatus as defined in claim 10 wherein one of the guide holders is stationary and the other guide holder is spring biased to provide a floating gripping hold on the article.  
 13. An apparatus as defined in claim 12 wherein the floating guide holder includes a guide element, a support means and two laterally displaced springs disposed between the guide element and support means.  
 14. An apparatus as defined in claim 10 wherein the article moving means includes a channel runner extending along said path, and  
 each pocket section includes roller means located on the carrier block and adapted to roll within the channel runner.  
 15. An apparatus as defined in claim 14 wherein the roller means includes two rollers contacting a first side of the channel runner and a third roller contacting the side opposing the first side of the channel runner.  
 16. An apparatus as defined in claim 10 wherein each pocket means includes means for stabilizing each pocket as it changes direction along a closed loop path having at least one straight section.  
 17. An apparatus as defined in claim 16 wherein the closed loop chain moves around a sprocket member,  
 each carrier block has a shaped seating bottom surface and a stabilizing abutment surface,  
 said stabilizing means includes a pair of pivotally mounted elements having a stabilizing surface which engages the abutment surface of the carrier block when the chain moves around the sprocket member.  
 18. An apparatus as defined in claim 17 wherein said sprocket member includes a contoured nesting surface for receiving the shaped seating surface of the carrier block.  
 19. An apparatus as defined in claim 1 wherein the wrapping material is a heat scalable material,  
 a heating assembly is disposed at a heat sealing work station located downstream from the folding work station,  
 said heating assembly being effective to seal together the overlapping ends of the wrapping sheet.  
 20. An apparatus as defined in claim 19 wherein the heating assembly includes a spring biased heating element which extends across the width of the package and is movable between a resting position and a sealing position.