US3572004A

US3572004A - Packaging apparatus

Info

Publication number: US3572004A
Application number: US744848A
Authority: US
Inventors: Keith Stewart Carmichael
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1968-07-15
Filing date: 1968-07-15
Publication date: 1971-03-23
Anticipated expiration: 1988-03-23

Abstract

An apparatus for packaging articles such as cans in an overwrap of thermoplastic polymeric material is provided wherein said apparatus comprises means for grouping a plurality of articles to be packaged, means for enwrapping said articles with said film, means for heat sealing overlapped edge portions of said film and enclosing said articles therewithin, means for separating said film-enwrapped grouped articles, and means for shrinking said heat-sealed film to provide a package of grouped articles characterized by a substantially wrinkle-free film extending over the top, bottom, sides and portions of the ends of said grouped articles.

Description

United States Patent 3,381,443 5/1968 Copping 3,397,465 8/ 1968 Carmichael 3,404,508 10/1968 Dreyfus....,....... 3,417,540 12/1968 Copping et Primary Examiner-Theron E. Condon Assistant Examiner-Robert L. Spruill Attorney-Claude L. Beaudoin [73] Assignee EJ. du Pont de Nemours and Company Wilmington, Del.

ABSTRACT: An apparatus for packaging articles such as cans in an overwrap of thermoplastic vided wherein said apparatus com plurality of articles to be package articles with said film, means portions of said film and enclosin means for separating said film and means for shrinking said heat-sealed film to package of grouped articles characterized b wrinkle-free film extending over the top, b

3,513,620 5/1970 Billingsley et al. 53/184X portions of the ends of said grouped articles.

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ATTORNEY PATENTED W23 I97I 3572, 004

SHEET is [1F 1 I *5/77? 5 FM/Mia ATTORNEY PACKAGING APPARATUS THE INVENTION The present invention relates to a packaging method and apparatus and, more particularly, is directed to a novel method and high-speed apparatus for continuously and automatically packaging groups of articles to form packaged units of increased suitability for efficient handling, transport, and storage. More specifically, the invention relates to a new method and high-speed apparatus for packaging cylindrical articles such as cans to form a package consisting of six cans which is commonly referred was a six-pack using continuously supplied flexible heat-sealable and heat-shrinkable film or sheet of preferably transparent material.

Packaging arrangements and apparatus heretofore employed have involved bringing groups of articles and individual preformed package units into operative association in a noncontinuous manner, but rather intermittent in the operation of at least a number of the significant packaging steps and apparatus components. This has prevented the attainment of high packaging speeds and has resulted in fairly complex indexing mechanisms or drives. In the package resulting from the arrangement of this invention, the articles, or cans, themselves are not only supported and contained thereby, but actually form an integral and necessarypart of the package providing structural unity and stability to the otherwise unrelated sleeve member. The packed articles are a necessary component of the package so that the placing and securing 'of the articles into proper position with respect to each other and the package components must be carried out substantially concurrently to effect formation of the package. Accordingly, it is the principal object of the present invention to provide a packaging apparatus especially adapted for continuous and high-speed packaging operation.

According to the present invention there is provided a method and an apparatus for packaging articles such as, for example, cylindrical cans in an overwrap of thermoplastic polymeric material in film form; said apparatus comprising means for providing a plurality of grouped articles to be packaged, means for providing said film, means for enwrapping said articles with said film, means for heat sealing the overlapped edges of said film and enclosing said articles to be packaged therewithin, means for separating said articles to be packaged therewithin, means for separating said film-enwrapped grouped articles, and means for shrinking said heatsealed film to provide a package of grouped articles characterized by a substantially wrinkle-free film extending over said grouped articles.

The apparatus of the present invention is automatic and of continuous operation, receives a continuous stream of regular articles of substantially uniform size, separates the articles into spaced groups, moves said groups of articles continuously along a given line of movement, forms continuously supplied flexible film around said groups as the groups move along said line of movement, continuously seals the overlapped edges of said flexible film to form a unitary sleeve assembly surrounding said groups as they move along said line of movement, continuously severs the sleeve assembly between said groups to form individual groups of articles each enclosed by a tubular sleeve member having open end portions, shrinks the open end portions of each sleeve member into engagement with the articles at the ends of the contained group of articles, and then further shrinks each entire sleeve member into close engagement with all of the articles in its contained group.

The nature and advantages of the invention will be more clearly understood by the following description and the FIG. 3 is a perspective view of a preferred package produced by the apparatus of the invention;

FIG. 4 is a plan view of the initial film-forming means of the apparatus of FIG. 1;

.FIG. 5 is a partial side elevation of the initial forming means of FIG. 4;

FIG. 6 is a partial end elevation of the forming means of FIGS. 4 and 5;

FIG. 7 is a partial plan view of the final film-forming means of the apparatus of FIG. 1;

FIG. 8 is a partial side elevation of the film-forming means of FIG. 7;

FIG. 9 is an end elevation view of the film-forming means of FIG. 7;

FIG. 10 is a partial plan view of the film-forming means and the film-sealing means of the apparatus of the invention;

FIG. 11 is a partial side elevation of the apparatus means shown in FIG. 10; I

FIG. 12 is an end elevation view taken along lines 12-12 of FIG. 10;

FIG. 13 is a partial plan view of the sealing means of the apparatus of FIG. 1',

FIG. 14 is an end view of the sealing means of FIG. 13;

FIG. 15 is a side elevation view of the sealing means of FIG.

FIG. 16 is a side elevation view of the film supply means of the apparatus of FIG. 1;

FIG. 17 is an and elevation view of the film supply means of FIG. 16;

FIG. 18 is a plan view of the film supply means of FIG. 16;

FIG. 19 is a side elevation of the film-separating and package-forming section of the apparatus of FIG. 1;

several views illustrated in the accompanying drawings FIG. 20 is a perspective view showing in greater detail the film-separating and package-forming means of FIG. 19;

FIG. 21 is a transverse cross-sectional view of the preshrink means of the apparatus of FIG. 1;

FIG. 22 is a side elevation view of the preshrink means of FIG. 21;

FIG. 23 is a perspective view showing the control features of the preshrink means depicted in FIG. 21;

FIG. 24 is a perspective view of the final heat-shrink means of the apparatus shown in FIG. 1;

FIG. 25 is a transverse cross-sectional view of the air supply module of the final shrink means of FIG. 1;

FIG. 26 is a longitudinal cross-sectional view along lines 26-26 in FIG. 25; and

FIG. 27 is a transverse cross-sectional view of the exhaust module of the final heatshrink means of the apparatus shown in FIG. 1.

GENERAL DESCRIPTION TI-Ie packaging apparatus herein disclosed in illustration of the invention is shown in FIGS. 1 and la and comprises in cooperative association and assembly an article feed section 100, an article-grouping section 200, a film-tube forming section 300, a film supply section 400, a film-tube separating and package-forming section 500, a film preshrink section 600 and a film final shrink section 700. The motive power for driving the apparatus of the invention is shown in FIGS. 2 and 2a and comprises drive power section 800 and drive power section 900.

The mechanical members constituting the apparatus of the present invention as shown in FIGS. 1 and 1a are supported in cooperative association by a base frame support assembly 10 composed of suitable main frame members 11 so constructed and arranged as to present a support frame resting upon a plurality of suitably disposed leg members such as 12 that are secured to said frame.

The general operation of the apparatus of the present invention is that articles 13 to be packaged such as cans, bottles, etc., are aligned in adjacent rows 14 and 15 in article feed section which advances the aligned articles in the direction of arrow A. The advancing articles next enter into article-grouping section 200 wherein the aligned articles are accumulated and formed into groups of any number of articles, preferably six in number. The article groups are automatically spaced from each other and advanced into the film-tube forming section 300. The travelling spaced article groups are enwrapped with a preferably transparent flexible wrapping film 18 which is fed continuously from a source or supply thereof in roll form from film supply section 400. The wrapping film is transformed in section 300 from a flat sheet into a tubular structure that enwraps the continuously travelling line of spaced article groups, and the opposed longitudinally extending edges of the wrapping film are overlapped a suitable amount and heat sealed together in the region of the overlap to provide a continuous tubular film that surrounds the travelling line of spaced article groups. The enwrapped or encased travelling line of spaced article groups are preferably next separated into separate article groups by advancing through film-tube separating and package-forming section 500 wherein the tubular film is severed automatically at a point intermediate each adjacent spaced article group in the line thereof. The separate overwrapped article groups are next each advanced through a preshrink section 600 wherein a heated medium, preferably air, is directed against substantially only the end portions thereof whereby to selectively preshrink each end of the tubular wrapping film against the end articles of the article groups. The article groups are next advanced through a final shrink section 700 wherein each package is subjected to a heated medium over substantially its entire surface thereby to shrink the entire tubular wrapping film to provide a unitary package of wrapped articles characterized by a wrapping film tightly drawn over the sides, top, bottom and portions of the ends of each article group. The preferred package of six articles is shown in FIG. 3 which depicts two contiguous rows 16 and 17 each containing three containers enwrapped with a tightly fitting heat-shrunk film 18 of flexible, transplant thermoplastic material such as, for example, polyethylene. As shown in FIG. 3, the overlapped edge portions of the film wrap is at 19 and the heat seal in the region of the overlap is along heat seal lines 20 and 21 that are disposed in a parallel manner with respect to each other. Suitable holes 22 may be provided in the region of the film overlap between four contiguous cans to provide carrying aids adapted to accommodate fingers for lifting and carrying the package.

A more detailed description of the apparatus of the present invention is set out herebelow.

ARTICLE FEED Referring to FIG. 1, articles 13 to be packaged are supplied from any convenient source to article feed section 100 consisting of an endless belt-type conveyor 101 having

guide rails

102 and 103 suitably secured thereto for receiving the articles 13, aligning articles 13 in two contiguous rows 14 and 15 and advancing the rows of articles continuously in the direction indicated by arrow A. The endless belt of conveyor 101 may be of any suitable material and construction adequate to provide reliable and economical service. The article-feeding device is preferably provided with a sensor means 104 for monitoring the flow of articles advancing therepast. The sensor means 104 is a proximity switch adapted to halt the operation of the apparatus upon detecting the absence of any flow of metallic articles therepast. The sensor 104 operates by means of magnetic field principles and is well known in the art. The sensor 104 is thus a convenient control feature for providing ptimum operation of the apparatus.

ARTICLE GROUPING The article-grouping section 200 consists of endless belt conveyor 101 and article-grouping

screws

201 and 202 suitably mounted in spaced parallel fashion to accommodate the two contiguous rows 14 and of articles 13 therebetween.

Screws

201 and 202 are of substantially identica] design each having a helical screw lead 203 characterized by a variable screw pitch from the inlet end 204 to the outlet end 205 thereof, except that they are oppositely threaded. The

screws

201 and 202 are suitably mounted for rotation as in bearings 206 and 207, and when rotated each acts upon the row of articles immediately adjacent thereto so that rows 14 and 15 are advanced by the conveyor 101 in timed relationship with each other. Also, the variable pitch feature of

screws

201 and 202 acts to separate the aligned articles into spaced groups of articles each consisting preferably of six articles. The foregoing is illustrated in FIG. 1 which shows the articles 13 in both rows 14 and 15 thereofin close and contacting relationship with each other upon entering into the article-grouping section. After advancing along the

screws

201 and 202, the articles 13 are shown in spaced groups 209 of six articles that are separated from each other by space 210. It should be noted that

screws

201 and 202 neither directly advance nor actually push the articles towards the exit end 205 thereof, but actually function both to restrain the advancement of the articles 13 (which is accomplished by belt conveyor 101) thereby to accumulate the articles and to meter the articles therefrom in spaced groups each consisting of preferably six articles. The article-grouping means 200 continuously meters or transfers article groups 209 to the film-tube forming means 300.

FILM-TUBE FORMING The film-tube forming means 300 includes an endless belttype conveyor 301, article group transfer and film former means 302, film former means 303, film-sealing means 304 and film-advancing means 305.

Conveyor means 301 is shown schematically in FIGS. 2, 2a, 4 and 5 and comprises

endless chains

306 and 307 having support pads 308 and rods 309 spaced there'along and connected therebetween to provide an endless belt-type conveyor for supporting thereon and conveying article groups 209. The endless conveyor 301 is adapted to be driven by suitable means such as rotatable sprocket wheels 310 that engage

endless chains

306 and 307. The sprocket wheels 310 are suitably secured to shaft 311 that is rotatably mounted to the supporting frame assembly 10. The endless conveyor 301 is so constructed and arranged as to travel around idler sprocket assemblies 312 and 313 each consisting of rotatably mounted shafts having sprocket wheels thereon engaging

endless chains

306 and 307 to present a long horizontal line or path of movement between idler sprocket assemblies 312 and 313 that is cooperatively disposed and aligned in relation to endless conveyor 101.

A salient feature of the apparatus of the present invention resides in the disposition and association of means collectively referred to as means 302 for transferring article groups 209 from conveyor 101 to conveyor 301 and onto wrapping film 18 and, additionally, transforming wrapping film 18 from a flat sheet to a shaped sheet having a U-cross-sectional shape. The organization of means 302 is more clearly shown in FIGS. 4, 5 and 6 and includes means 314 fashioned preferably of stainless steel having an oval cross section (FIG. 6) suitably secured to a bracket 315 which is itself secured to inverted U- shaped bracket 316 mounted to frame members 11. Means 314 is characterized by a substantially flat bottom section 317 and curved side sections 318 having a leading edge 319 providing a curved surface from top to bottom over which film 18 is adapted to be continuously drawn or advanced for transfonning the film from a flat sheet to a U-shaped sheet having a substantially flat and wrinkle-free bottom section. As shown in FIGS. 4 and 5, screws 201 and 202 extend through the interior of film forming means 314 and are rotatably mounted at their respective ends to journals secured to U-bracket 316. In operation, screws 201 and 202 first meter article groups 209 into film-forming means 314 and onto the wrapping film 18 being advanced over bottom portion 317 and then meter article groups 209 continuously in timed relation onto pads 308 of endless conveyor 301. As shown in FIG. 1, article groups 209 exit from means 302 and advance towards means 303 with wrapping film 18 extending over the entire bottom and "up" constructed and arranged as to urge the edges of wrapping film 18 into overlapping relation. The organization of filrn former means 303 is more clearly shown in FIGS. 7 to 12, inclusive. The forming plate 318 is maintained in inverted U- shaped'position by being secured to adjustable posts 322 that are supported on crossbars 323 by means of a suitable knob means 324. Posts 322 are preferably threaded and engage knobs 324 through a cooperatively threaded aperture extending through the latter to facilitate the vertical adjustment or position of forming plate 318 thereby to accommodate article groups 209 of different height. Crossbars 323 are adjustably supported at each end by support posts 325 that are secured at their base 326 to frame member 11.

Resilient members 321 are preferably wide rubber wheels rotatably mounted at one end of a lever means 327 that is pivotably mounted at its other end to a bar shaft 328. Each bar shaft 328 is secured to a post 329 that is in turn secured to an adjustable bracket 330 that engages a support post 325. Bracket 330 is preferably provided with suitable means such as a thumb screw 331 to facilitate the vertical adjustment thereof on support post 325, as well as a thumb screw 332 to facilitate the vertical position of engagement thereof with post 329. Resilient members 321 are biased against the top section 319 of film-forming plate 318 by resilient means such as spring vmembers 333 that are suitably secured to bar shaft 328 and lever means 327 to urge the latter downwardly and transmit a downward force upon resilientrnernber's 321. Thus, resilient members 321 are tensioned to exert a firm pressure or contact with forming plate 318.

Referring especially to FIG. 7, it is seen that resilient members 321 contactfilm-forrning plate 318 in an oblique manner, i.e., the axis of resilient members 321 is not perpendicular to the major axis along the length direction of forming plate 318. The disposition of resilient members 321 at an angle or oblique manner with respect to forming plate 318 causes resilient members 321 to urge the film material 18 advancing therepast between forming plate 318 and resilient members 321 towards the center of forming plate 318, and the succession of pairs of resilient members, such as the total of three pairs shown in FIGS. 7 and 10, causes the edge portions of wrapping film 18 to overlap as shown at 334. The amount of overlap desired may be achieved by adjusting the angular position or relation of resilient members 321 with respect to form ing plate 318 by manipulating adjustable thumb screws 331 or 332 to achieve the desired result. As shown in FIGS. 1 and 10, article groups 209 exit from film former 303 and advance towards sealing means 304 with wrapping film 18 enclosed around both sides and the top and the bottom of the article groups.

The sealing means 304 includes atleast one heated sealing wheel 335 disposed on an adjustable support assembly 336 and aligned to contact the wrapping film 18 in the region of film overlap 334 for heating the lapped film layers and sealing them together. The support assembly 336 comprises a cradle member 337 having spaced bars 338and a hollow crossbar member 339 secured at both ends therebetween. Bar members 338 are suitably movably secured at one end to frame member 11 or any suitable stationary component of the apparatus. Hollow crossbar member 339 is so constructed and arrange to accommodate a screw and travelling yoke assembly consisting of screw 340 operatively connected to actuation means 341 and yoke 342 which engages screw 340 and slot 343 of crossbar 339 for slideable movement therealong upon rotating screw 340 by turning actuating means 341. Referring to FIG. 13, it is seen that yoke 342 is adapted to accommodate a shaft 344 to which a sealing wheel 335 is connected at one end; the other end of shaftv344 is connected to a drive wheel 345 which is in turn operatively connected to a shaft 346 adapted to slidably and rotatably engage sprocket gear 347 operatively disposed for engagement with suitably driven chain means (not shown). Sealing wheel 335 is adapted to be heated for sealing the wrapping film 18 by means of power supply slip rings 349 and 350 that are operatively connected to conductor 351 and adapted to contact electrically energized

terminals

352 and 353, respectively, whereby conductor 351 transmits the energy for heating sealing wheel 335.

A slip ring 354 assembly is also provided on shaft 344 which is used to pick up the low voltage from a thermocouple 392 secured to sealing wheel 335 and passes the electrical signal to a controller (not shown). The thermocouple wires are connected to the slip ring 354. The voltage is passed from the rotating slip ring 354 to the controller by means of a braided wire surface 391 which is pulled against the slip ring surface by means of tension created by springs 390. Wires, which are connected to the braided surfaces, are connected to the controller for monitoring the voltage, and the controller is calibrated in terms of temperature for adjusting the power to the sealer to maintain a desired sealing temperature. Additional sealing wheels 335 may be connected in tandem by providing support bars 355 and 356 rotatably secured at one end to shaft 344 and extending outwardly from yoke 342 to provide a framework for supporting additional assembliesof slip rings, thermocouples and electrically energized terminals, as shown in FIG. 13. The additional sealing wheels are conveniently rotated by means of a belt 360 operatively connected between drive wheels 345. The sealing wheels 335 may be positioned at any desired transverse location in the region of film overlap 334 by suitably manipulating actuating means 341 for advancing yoke 342 and associated members attached thereto along screw 340. Also, each sealing wheel 335 may be mounted at a different transverse location of overlap 334 to provide a plurality of heat-seal lines as 20 and 21 shown in FIG. 3.

Sealing wheels 335 preferably contact overlap portion 334 under pressure which is transmitted thereto by means of pneumatically operated pressure cylinder 357 which is secured at one end to crossbar member 339 and so constructed and arranged to transmit a downward force upon crossbar 339 which is transmitted through yoke 342 to sealing wheel(s) 335. Sea]- ing wheel(s) 335 contact the area of film overlap 334 advancing therepast between an extension 318' of forming plate 318 (see FIG. 11) and the sealing wheels. Thus, sealing wheel(s) 335 heat seal the overlapped film layers by means of heat and pressure. The heat-seal line whereat the overlapped film is sealed is shown at 358 in FIG. 10. As shown in FIGS. 1 and 10. article groups 209 exit from film-sealing means 304 and advance towards film-advancingmeans 305 enclosed in a sleeve of wrapping film l8.

Film-advancing means 305 includes an endless belt 361 adapted to advance continuously between suitable sprocket assemblies such as 362 secured to a supporting frame 363 which is in turn secured to main frame members 11 of base frame assembly 10. Endless belt 361 is preferably fashioned of a plurality of transversly disposed members 364 suitably secured to driving chains (not shown) engaging spaced sprockets 362 one of which may be operatively connected to a driven shaft 365 (FIG, 2). Endless belt 361 is adapted to contact the top portion of article groups 209 and thus firmly secure article groups 209 that are within the sleeve of wrapping film between it and endless belt conveyor 301 for pulling the wrapping film 18 from the roll supply thereof. through film-tube former means 302 and 303 and film-sealing means 304. The wrapping film 18 is obtained from film supply 400.

= FILM SUPPLY- frame arrangement of side frame members 402 joined to end

Claims

1. Apparatus for packaging articles comprising conveying means for advancing said article s continuously along a given path of movement; means for accumulating and grouping a plurality of said articles into spaced groups thereof each consisting of at least two articles adapted to advance continuously along said path; means for supplying a wrapping film of heat-sealable and heatshrinkable organic thermoplastic polymeric material in the form of a single flat sheet adapted for continuous movement along said path; film-advancing means including an endless top belt adapted to advance continuously; means for placing said advancing article grOups onto said wrapping film and forming said wrapping film from a flat sheet thereof into a U-cross section extending across the bottom and up both sides of said article groups; means for engaging and overlapping each edge portion of said wrapping film to provide a region of overlap of said wrapping film consisting of at least two layers thereby enwrapping said advancing article groups with said wrapping film extending across the top, bottom and both sides of said article groups; means for heat sealing said layers of wrapping film in said region of overlap thereby to provide a continuous sleeve of wrapping film about said article groups; means for severing said sleeve of wrapping film intermediate said spaced article groups to provide a package consisting of separate article groups and a sleeve of wrapping film thereabout having open end portions which extend beyond each end of each article group; an endless bottom conveyor for continuously moving said article groups through said apparatus, said endless top belt of said film-advancing means being positioned above said article groups and adapted to be driven in timed relation to said endless bottom conveyor, the film being held in position on one side of said means for severing said sleeve between said endless bottom conveyor, said article groups and said endless top belt to said film-advancing means and being held in position on the other side of said means for severing said sleeve between said endless bottom conveyor, said article groups and another endless top belt spaced from said endless top belt of said film-advancing means whereby said sleeve is maintained taut thereby to better and more easily perform the sleeve-separating operation, said means for severing said sleeve being adapted to pass between the spaced said endless top belts to separate said sleeve; means for directing a heated gaseous medium against only said open end portions of said sleeve of wrapping film for first shrinking each end of said sleeve into engagement with the ends of each of said article groups; and means for directing a heated gaseous medium against each of said packages for shrinking said sleeve of wrapping film into engagement with said article groups thereby to provide a package characterized by a substantially wrinkle-free wrapping film extending over the top, bottom, side and portions of the ends of said article groups.

2. The apparatus of claim 1 wherein said another endless top belt engages the top portion of said sleeve thereby to restrain and firmly hold said sleeve in position as it advances across said severing means, and is a part of said means for directing a heated gaseous medium against only the end portions of said sleeve of wrapping film.

3. The apparatus of claim 1 including power drive means operatively connected thereto for operating said conveying means, accumulating and grouping means, film supply means and severing means in predetermined synchronized relationship.

4. The apparatus of claim 2 wherein said severing means includes a knife element having a serrated cutting edge secured to a reciprocably mounted travelling block operatively connected to a cam plate for reciprocating said knife for cutting said sleeve and moving said knife in the direction of said path of movement in synchronized relationship to said advancing article groups for cutting said sleeve of wrapping film intermediate said spaced article groups.