US3676979A

US3676979A - Substrate transport means for skin packaging machines

Info

Publication number: US3676979A
Application number: US85914A
Authority: US
Inventors: Thomas L Schuette
Original assignee: Possis Machine Corp
Current assignee: Possis Machine Corp
Priority date: 1970-11-02
Filing date: 1970-11-02
Publication date: 1972-07-18
Anticipated expiration: 1989-07-18

Abstract

A flat apertured endless belt has an upper stretch riding on air intake grills. Its apertures register with the air intakes to apply suction to the underside of substrate on it. Substrate lengths are impositively driven toward said stretch, faster than it moves, along a feed table having its top surface parallel to but above that of said stretch. Downstream from the table a hold down finger forces the medial portion of each substrate length into tractive engagement with the belt while its side edge portions are supported by rails coplanar with the table top, bowing it to an upwardly concave transverse curvature which insures that the length behind it will edgewise abut it.

Description

United States Patent Schuette [54] SUBSTRATE TRANSPORT NIEANS FOR SKIN PACKAGING MACHINES [72] Inventor: Thomas L. Schuette, Osseo, Minn.

[73] Assignee: Possis Machine Corporation, Minneapolis,

Minn.

[22] Filed: Nov. 2, 1970 [21] Appl. No.: 85,914

[52] U.S.Cl. ..53/1l2 A,53/l40, 271/74 [51] Int. Cl... ..B65b 35/28 [58] Field ofSearch ..53/140, 22 A, 112A; 271/74 [56] References Cited UNITED STATES PATENTS 3,533,212 10/1970 Borel et a1. ..53/10 X 2,927,409 3/1960 3,477,558 11/1969 Heyer Fleischauer ..271/74 X 1 1 July 18,1972

Gutierrez ..27l/74 X 3,172,526 3/1965 Buccicone ..l98/4l Primary ExaminerTravis S. McGehee Attorney-Ira Milton Jones [57] ABSTRACT A fiat apertured endless belt has an upper stretch riding on air intake grills. Its apertures register with the air intakes to apply 1 suction to the underside of substrate on it. Substrate lengths are impositively driven toward said stretch, faster than it moves, along a feed table having its top surface parallel to but above that of said stretch. Downstream from the table a hold down finger forces the medial portion of each substrate length into tractive engagement with the belt while its side edge portions are supported by rails coplanar with the table top, bowing it to an upwardly concave transverse curvature which insures that the length behind it will edgewise abut it.

14 Claims, 9 Drawing Figures PATENTED JUL1 |972 3,676,979

SHEET u or 4 Thuzzzasl. 501m SUBSTRATE TRANSPORT MEANS FOR SKIN PACKAGING MACHINES This invention relates generally to improvements in machines for skin packaging, and is concerned moreparticularly with improved means in such a machine for advancing substrate material, such as paperboard, past successive processing stations at one of which a film of thermoplastic skin forming substance may be deposited over the substrate material and at another of which suction may be applied to the underside of the substrate material to draw the film down into snug engagement therewith.

One form of skin packaging machine is disclosed in the copending application of Melvin J. Straub and myself, Ser. No. 842,99l,filed July 18, 1969 now US. Pat. No. 3,596,432 and assigned to the assignee hereof. In that machine a continuous length or web of a substrate material such as paperboard is unwound from a coil thereof on a supply reel and is advanced along a defined path, past a loading station at which articles to be packaged are placed on it at lengthwise spaced intervals. Next it moves past a coating station at which a film of molten thermoplastic material issues from a nozzle onto the articles and the substrate. As the web continues to advance, and before the thermoplastic film has hardened, the film is sucked down into snug engagement with the articles and the top surface of the substrate material around them by the application of suction to the underside of the substrate, to draw air through pores or small apertures in it. The substrate finally moves to a cutting station at which it is cut into discrete lengths, each comprising an individual package.

Prior skin packaging machines in which the film material was applied in molten form were mainly confined to use with continuous lengths of substrate, because the use of such machines with discrete lengths of substrate posed certain problems that had not heretofore been solved satisfactorily. With a continuous web, the air intake at which suction is applied is at all times covered by substrate, so that good suction is assured. But with short lengths, any interval or gap between adjacent pieces traversing the suction intake would afford a large air intake opening which could soreduce suction that air could not be drawn through the substrate to suck down the film.

On the other hand, if thin, fiat pieces of paperboard or the like are urged edgewise toward one another in an effort to prevent gaps between them, they tend to slide up onto one another, into a partially masking relationship that prevents deposition of film on portions of their top surfaces.

It is of course desirable that a skin packaging machine be adaptable for use with substrate material that is in either continuous strip form or discrete lengths, in order for the machine to have the maximum utility; and with this in mind it is an object of the present invention to provide means enabling a skin packaging machine to accommodate discrete lengths of substrate material as well as continuous strip or webs or substrate material.

It is another object of this invention to provide a skin packaging machine that can be operated with either pre-cut or continuous web substrates, and can be readily adjusted to accommodate substrates of substantially different widths without loss of suction when the narrower substrates are used.

Another and more specific object of this invention is to provide transport means for advancing substrate material (either precut or continuous) from station to station through a skin packaging machine, and wherein suction applied to the underside of the substrate material not only evacuates the space beneath a thermoplastic film thereon but also draws the substrate material into good tractive engagement with the transport means.

It is also a specific object of this invention to provide, in a machine in which discrete lengths of paperboard or the like must be advanced along a defined path in edge-to-edge abutting relationship, means for achieving and maintaining such edgewise abutment as the lengths of material are advanced along the path, and for preventing the lengths of material from overriding and overlapping one another as well as for preventing them from separating or spreading into spaced apart relationship.

Another specific object of this invention is to provide simple means in a skin packaging machine for preventing rolling displacement of articles to be packaged that have been deposited onto substrate material as it moves through the machine, thereby assuring that such articles will remain in predetermined positions relative to one another and to the substrate material.

With these observations and objectives in mind, the manner in which the invention achieves its purpose will be appreciated from the following description and the accompanying drawings, which exemplify the invention, it being understood that such changes in the specific apparatus disclosed herein may be made as come within the scope of the appended claims.

The accompanying drawings illustrate one complete example of the embodiment of the invention constructed according to the best mode so far devised for the practical application of the principles thereof, and in which:

FIG. 1 is a more or less diagrammatic perspective view of a portionof a skin packaging machine embodying the principles of this invention, and particularly of the means by which discrete lengths of substrate are brought into edgewise abutting relationship;

FIG. 2 is a view in vertical section, on an enlarged scale, of substantially the portion of the machine that is shown in FIG.

FIG. 3 is a sectional view taken on the plane of the line 33 in FIG. 2;

FIG. 4 is a plan view of portions of the machine in the neighborhood of the film applying station, with parts s'hown broken away to illustrate details of construction;

FIG. 5 is a sectional view taken on the plane of the line 5-5 in FIG. 4;

FIG. 6 is a sectional view taken on the plane of the line 6-6 in FIG. 4;

FIG. 7 is a sectional view taken on the plane of the line 7 -7 in FIG. 6; and

FIG. 8 is a diagrammatic perspective view of the means for holding articles to be packaged by the machine against displacement out of their desired locations on the substrate as the substrate is moving toward the film applying station;

FIG. 9 is a fragmentary perspective view of the conveyor belt illustrating a feature which may be employed to facilitate stripping accidentally deposited plastic film from the belt.

Referring now to the accompanying drawings, the numeral 5 designates generally a skin packaging machine in which substrate material 6 is advanced along a defined generally horizontal path that carries it past a loading station 7 (indicated in broken lines in FIG. 4) at which articles 8 to be packaged are deposited upon it, and then past a station 9 (also indicated in broken lines in FIG. 4) at which a film of thermoplastic substance is deposited over each article and at least that portion of the upper surface of the substrate that surrounds the article.

The substrate material comprises precut rectangular lengths or panels of paperboard or the like, which may be individual cards, one for each article, or can be long enough to comprise several packages and to be cut transversely into a number of identical cards. It will be apparent as the description proceeds that the mechanism herein disclosed could operate equally well with substrate material in continuous web form, drawn from a roll thereof.

As the substrate material moves downstream past the load ing station 7, the articles 8 are successively deposited onto it at spaced intervals along it, each article being so disposed that it will occupy a central portion of one of the cards into which the panel is to be cut. The loading station 7 can be of any conventional type by which articles are conducted down toward the substrate from a level above the same and are deposited onto the substrate at uniform time intervals. It will be apparent from the principles of this invention are applicable to machines in which articles are loaded manually, and also to those intended merely for applying a coating of film or the like to a substrate.

The film applying station 9 can be of the type disclosed in the above mentioned application Ser. No. 842,99l, to which reference can be made for further details. In any event it comprises a nozzle (not shown) from which molten thermoplastic substance issues to coat the articles and the top surface of the substrate material.

The means for advancing substrate downstream through the machine comprises an endless flat belt 12 and rollers 13 around which it is trained. The rollers are rotatably mounted on an elongated machine frame 14 with their axes horizontal and transverse to the path along which the substrate advances, and they are spaced apart a substantial distance along said path to provide an elongated straight upper stretch 15 of the belt. To drive the belt so that its upper stretch will move in the downstream direction, at least the roller 13 at the downstream end of the upper stretch is driven by an electric motor (not shown) or similar power means, through a suitable transmis- 81011.

As it moves, the upper stretch of the belt passes in succession over a suction manifold 16 and a vacuum table 17, both of which are supported by the machine frame 14 between the rollers 13. The suction manifold 16 extends lengthwise of the upper belt stretch from near the upstream roller 13, past the loading station 7, to a point adjacent to the vacuum table 17.

The belt has a pattern of grooves opening to its outer surface, which provides mouths through which the suction in the manifold 16 and in the vacuum table 17 is applied to the underside of substrate on the upper stretch of the belt. Across one-half of the width of the belt these grooves, designated 20t,

are oriented transversely of the belt and extend from near one edge of the belt (which for convenience may be considered its rear edge) to almost the middle of the belt. In the other half of the belt width, the grooves, designated 20L, extend lengthwise of the belt and are divided into successive ranks.

Holes 22 through the bottoms of the transverse grooves 20t near the inner ends thereof register with elongated slots 23 in the top of the manifold 16 so that as these grooves travel along the length of the manifold the suction therein will be manifested at the underside of substrate on the belt. Obviously as the hole 22 of each transverse groove comes into register with a slot 23, the entire length of the groove becomes a suction mouth so that substrate on the belt will be tightly held thereto regardless of its width.

The width of the belt of course determines the maximum width of substrate that can be handled by the machine; its minimum width is determined by the length of the transverse grooves. This follows from the fact that the substrate is always fed to the belt with one side edge thereof closely adjacent to the rear edge of the belt, it being understood that the width of the substrate must not be less than the length of the transverse grooves.

The longitudinal grooves have holes 24 through the bottom thereof by which they are communicated with suction manifested in the vacuum table 17, and since the holes 22 in the bottom of the transverse grooves also communicate with the vacuum table as they traverse the same, the vacuum table can apply suction to the underside of the substrate across the entire width thereof.

The vacuum table is essentially a flat metal slab 25 fixed to the machine frame with its top surface contiguous to the underside of the top stretch of the belt. A grid-like air intake opening to the top surface of the slab provides for suction to be manifested at the underside of the belt as it traverses the vacuum table. This grid-like air intake comprises three sets or groups of lengthwise extending grooves 26 which are laterally spaced apart by distances corresponding to the spacing between the longitudinal grooves 20L in the belt, and another lengthwise extending groove 27 positioned to align with the holes 22 in the transverse grooves 20!. For each set or group of grooves 26 there is a suction manifold 29 in the form of a transverse bore through the slab 25. The manifolds are connected with a suction source through ducts 30, and to commu nicate the grooves 26 as well as the groove 27 with the manifolds, all of the grooves are deep enough to intersect the upper portions of the bores that form the manifolds. Hence suction in the manifolds are not blocked between the grooves and the source of suction. Thus by providing adjustable closures for the bores, the effective width of the grid-like air intake can be correlated to any given width of substrate between minimum and maximum. Inasmuch as the minimum width of substrate for which the machine is designed, is somewhat greater than the length of transverse grooves 201, the groove 27 is never cut off from communication with the manifolds, but communication of the grooves 26 with the manifolds is controllable by piston-like plugs 31 that are slidably received in the bores.

The plugs 31 are formed or rubber or neoprene, and as shown in FIG. 6, are confined between the inner end ofa tube 32 and the head 33 of a screw threaded rod 34 that extends through the tube and has a knurled adjusting nut 35 threaded thereon and bearing against the outer end of the tube. Obviously by adjustment of the nut, the diameter of the plug can be increased or decreased, as needed to give the same a smooth sliding air tight fit in the manifold. Adjustment of the plugs to close off those of the grooves 20L that are not covered by substrate, is facilitated by knobs 36 secured to the outer ends of the rods 34.

The suction manifold 16 comprises a square tube extending lengthwise of the belt. lts opposite ends are plugged and it is connected in any suitable manner with a source of suction. The flat top surface of the tube upon which the longitudinally medial portion of the upper belt stretch rides, has the lengthwise extending air intake slots 23 formed therein to register with the holes 22 in the belt.

Where the upper stretch of the belt rides on the narrow suction manifold, its laterally outer portions are supported by idler rollers 37 that are mounted on the machine frame at lengthwise spaced intervals. These rollers are upwardly tangent to a plane that lies slightly below the level of the top surface of the suction manifold, to insure that the belt will have good sealing engagement with the suction manifold as it slides therealong.

It will be apparent that the application of a good suction to substrate material on the belt is dependent upon there being no substantial gaps or breaks along the length of the substrate material that would offer a large opening through which air could freely enter the air intakes of the suction manifold or vacuum table.

The means for insuring that adjacent precut lengths of substrate material will move along the upper stretch of the belt in edgewise abutting relationship comprises, in general, a feed table 39 which has its discharge end portion overlying the upstream end of the upper belt stretch 15. A notch 40 is formed in the discharge end portion of the feed table. The side edges of this notch provide a pair of rail-like supports 41 which coact with a hold-down finger 42 to impart a transverse upwardly concave arcuate curvature to each length of substrate as it leaves the feed table, which, curvature, as will be described, assures against overlapping of successive lengths of substrate.

The feed table serves to carry panels of substrate material toward the belt from a sheet feeding station at the upstream end of the machine, where individual panels or lengths of precut substrate material are loaded onto the feed table oneby-one, either manually or by means of a conventional sheet feeding mechanism. The panels are forwarded along the feed table in lengthwise spaced apart relation by one or more sets of nip rolls 44 which are spaced upstream from the hold down finger 42. The nip rolls comprise a lower driven roller 45 which projects up through an aperture in the feed table to be upwardly tangent to a plane very slightly above that of the feed table surface, and a cooperating idler roller 46 above the driven roller. The driven roller 45, which can be drivingly connected by means of a belt or chain 47 with the upstream belt roller 13, tends to forward the substrate material at a speed faster than the rate of belt advance, but it has a smooth peripheral surface and can therefore slip on the substrate to some extent. The idler roller 46 has limited up and down motion, and is biased downwardly by a spring 48 to hold the substrate material in tractive engagement with the driven roller, By adjustment of the spring any desired degree of slippage between the driven roller and the substrate can be had.

Parallel fixed and

adjustable guide rails

49 and 50 extending lengthwise along the feed table engage the opposite side edges of the substrate to position it accurately across the width of the table and hold it straight. Since the narrowest substrate for which the machine is designed must overlie the transverse grooves 20t in the belt, the fixed guide rail is at the rear edge of the feed table, and it will be understood that the location of the adjustable rail is determined by the width of the substrate.

Adjustment of the rail 50 can be effected in any suitable,

manner.

The top surface of the feed table and hence the rail-like supports 41 provided by the side edges of the notch 40 in the feed table are elevated a small distance above the upper stretch of the belt, but the hold down finger 42, in the absence of substrate therebeneath, rides on the belt.

The hold-down finger is essentially a bar that extends lengthwise in the direction of substrate advance between the rail-like supports 41. It depends from a bracket 55 which is carried by the machine frame and extends over the belt from one side thereof. A pair of pins 56 project upwardly from the hold down finger, one near each end of it, and are slidably received in the bracket 55 to provide for limited up and down translatory and tilting motion of the finger. A coiled compression spring 57 on the front one of these pins reacts between the bracket and the finger to bias the downstream end of the latter downwardly toward the belt. The upstream end portion of the hold down finger has its underside chamfered or curved to facilitate its riding up onto an advancing length of substrate.

As best seen in FIG. 3, the hold-down finger engages the advancing substrate panel only along a lengthwise narrow zone between the rail-like supports 41, and in so doing presses this portion of the panel down below the level of the top surface of the feed table and onto the belt. The side edge portions of the panels are of course held at a higher level by the supports 41. Thus, as indicated, the hold-down finger cooperates with these supports to impart to the substrate a transverse upwardly concave arcuate curvature by which a medial portion thereof is disposed below the level of the top surface of the feed table while marginal side edge portions thereof extend substantially I above that level.

As each piece of panel of substrate material moves off the feed table and under the hold-down finger, its medial portion is engaged with the belt all along its length, and its trailing portion retains the transverse curvature just described until it leaves the rail-like supports 41. But before it does so the leading edge of the succeeding panel of substrate collides with the arcuately curved rear edge of the piece on the belt. Until the succeeding piece comes under the hold-down finger, it of course remains fiat, and therefore its straight front edge engages the bowed rear edge of the preceding panel at two spaced points, thus assuring edgewise abutment of the two panels and preventing the following one from overriding or underriding the leading one.

Until the succeeding piece or panel moves all the way under the hold-down finger, and into full tractive engagement with the belt (still in edgewise relationship to the panel ahead of it) its rear end portion does not pass out of the nip rolls which continue their tendency to advance the panel at a speed faster than that of the belt, and thus assures its edgewise abutting engagement with the panel ahead of it.

To give a signal which will initiate a cycle of sheet feeder operation or notify an attendant that a panel must be manually placed on the feed table, a limit switch 64 is' located downstream from the nip rolls. It is held open by substrate beneath it and closes when the trailing edge of a length of substrate passes out from under it. The provision of this switch insures that a length of substrate will not arrive at the hold-down finger too late to catch up with the panel of substrate ahead of it.

As the panels of substrate move along downstream from the hold-down finger, the articles to be packaged are placed on them at the loading station 7. If the articles are cylindrical (as for example flashlight cases) they would have a tendency to roll toward one edge or the other of the substrate, owing to the fact that the upper belt stretch has a slight hump along its medial portion where it rides on the suction manifold. To prevent such rolling of cylindrical articles that are magnetizable, a magnet 65 is mounted beneath the belt, having opposite pole shoes at opposite sides of the suction manifold. The pole shoes are elongated, or a plurality of downstream adjacent magnets can be used, so that the magnetic field produced thereby extends from the loading station at least to the downstream end of the suction manifold, and preferably a short distance past the film applying station.

The magnetic field produced by the magnet means holds the articles centered between the magnet poles and thus prevents the articles from rolling toward either edge of the belt. Once an article passes the film applying station 9, the film overlying it tends to hold the article against rolling, and therefore the magnet means need not extend any substantial distance downstream from the film applying station.

Although it is not intended that the molten thermoplastic be extruded from the nozzle at the film applying station 9, unless the conveyor belt is covered by substrate a malfunction of the sheet feeder may result in the molten plastic being discharged on to the uncovered surface of the belt. If that happens a plastic ribbon is formed which has a transversely undulated shape imparted thereto due to the transverse grooves in the belt. This undulated shape makes it difficult to strip the plastic ribbon from the belt, especially when minimum width substrate is being used. The tendency for the undulated ribbon to stretch like an accordion interfered with its removal from the belt.

The slight modification of the belt illustrated in FIG. 9, greatly minimizes this objection. By virtue of localized raised portions 60 that rise from the bottom of the transverse grooves 20t at spaced intervals along the length thereof, bridging ribs are formed across the undulations in an accidentally applied plastic ribbon, which resist accordion-like stretching. As shown, the tops of the raised portions are slightly below the outer surface of the belt so that despite their presence, the single hole 22 in each groove communicates the entire length thereof with the suction source.

From the foregoing description taken with the accompanying drawings it will be apparent that this invention provides means in a film coating machine for applying suction to the underside of substrate material upon which thermoplastic film is deposited, and for moving precut lengths of substrate material downstream through the machine in edgewise abutting relationship so that there no gaps between the lengths through which suction can be lost. It will also be apparent that the invention adapts the machine for use with substrate materials of different widths and for use with substrate in continuous web form as well as in precut lengths.

Those skilled in the art will appreciate that the invention can be embodied in forms other than as herein disclosed for purposes of illustration.

The invention is defined by the following claims.

lclaim:

1. In a packaging machine having a plurality of stations along a defined path, at one of which heated thermoplastic material is applied to substrate material and articles disposed thereon to form a film over each article and a portion of the substrate top surface that surrounds it, means for advancing substrate material with articles thereon from one to another of said stations and for applying suction to the bottom of the substrate material to suck the film down into snug engagement with the articles and the top surface of the substrate, the last named means comprising:

A. a vacuum table which has 1; an upwardly facing stationary top surface that is interrupted by a plurality of spaced apart air inlet openings which collectively form a station-ary air intake, and 2. manifold means communicating with said openings;

B. an endless flat belt having an upper stretch which fiatwise overlies and slides lengthwise across said stationary top surface of the vacuum table, said belt having apertures therethrough which register with said stationary air inlet openings as the belt travels across the vacuum table; and

C. means for applying suction to said manifold means, which suction is applied to substrate material riding on the belt as the apertures in the belt are brought into communication with said stationary air inlet openings, to cause the substrate material to tractively adhere to the upper stretch of the belt for advancement therewith and to draw air through the substrate material and thus evacuate the space beneath film thereon.

2. The packaging machine of claim 1, further characterized by means adapting the machine for use with discrete lengths of substrate material, the last mentioned means comprising:

D. means defining a feed table having its discharge end substantially over the upstream end of the top stretch-of the belt;

E. means for successively feeding discrete lengths of substrate material along said feed table off its discharge end and towards the belt at a speed which tends to be faster than that at which the top stretch of the belt travels; and

F. means at the discharge end of the feed table for imparting a transversely bowed shape to the trailing end of each length of substrate material as it leaves the feed table by which the next successive length of substrate material is prevented from overlapping it and is thus forced into edgewise abutting relation to it.

3. The packaging machine of claim 2, wherein said means for imparting a bowed shape to the trailing end of each length of substrate comprises:

G. substantially parallel longitudinal supports at the discharge end of the feed table spaced apart transversely of the belt and forming extensions of the feed table substantially parallel to the top surface of said stretch of the belt but elevated above the same; and

H. hold down means between said spaced apart longitudinal supports for forcing a medial portion of the substrate material downwardly below the level of said longitudinal supports.

4. The packaging machine of claim 3, wherein said hold down means is above the top stretch of the belt and biased downwardly to force the substrate material into tractive engagement with the top stretch of the belt.

5. The packaging machine of claim 1, wherein said stationary inlet air openings in the top surface of the vacuum table comprise lengthwise extending transversely spaced grooves opening to its upwardly facing surface, and wherein said manifold means comprises:

A. a transverse bore intersected by said grooves and communicable at one end with a source of suction;

B. a plug axially slidable in said bore to block communication between a selected number of said grooves and the source of suction to thereby adapt the vacuum table to different widths of substrate material without loss of suction; and

C. plug adjusting means connected to the plug and protruding from the other end of the bore.

6. In a packaging machine in which substrate material and articles to be packaged that are disposed thereon are carried in one direction along a defined path past a station at which heated thermoplastic material is applied to the articles and the substrate material to form a film over the same, means for moving substrate material along said defined path and for sucking film down into snug engagement with each article and with its surrounding portion of the substrate material, the last mentioned means comprising:

A. a flat endless belt which is at least as wide as the substrate material and which has apertures thereth rough at longitudinally and laterally spaced intervals;

B. roller means around which the belt is trained with a straight stretch thereof uppermost and extending along said defined path and which drives the belt for movement in said direction; and

C. air intake means between the roller means, having a stationary apertured top surface along which the upper stretch of the belt extends and with which it has intimate fiatwise supporting engagement, the apertures in said surface of the air intake means being so arranged that the apertures in the belt register with them to enable air to be 'drawn into the air intake means through the apertures in the belt and through substrate material on the belt.

7. The packaging machine of claim 6, further characterized by:

said apertures in the belt being defined by grooves in the outer surface of the belt, and holes through the bottom of at least some of the grooves.

8. The packaging machine of claim 7, wherein said holes in the belt are aligned in rows that extend parallel to the edges of the belt and are spaced transversely thereacross, further characterized by said apertures in the air intake means being defined by:

1. grooves that open to the top surface of the air intake means and extend lengthwise in said direction, said grooves being spaced apart laterally in correspondence with the transverse spacing of said holes in the belt so that the holes in the belt register with the grooves in the air intake means; and

2. the air intake means having a bore that extends transversely to said grooves therein and opens to them, which bore is connectable with a source of suction and thus provides for communication of said grooves therewith.

9. The packaging machine of claim 6, further characterized by means adapting the machine for use with discrete lengths of substrate material, the last mentioned means comprising:

A. a feed table having its discharge end substantially over the upstream end of said stretch of the belt;

B. hold down means adjacent to the discharge end of the feed table and above the receiving end portion of said stretch of the belt to urge the lengths of substrate material into tractive engagement with said stretch of the belt as they leave the feed table; and

C. longitudinally extending horizontal supports spaced laterally of the belt to opposite sides of the hold down means and substantially coplanar with the feed table to cooperate with the hold down means to flex the trailing end portion of each length of substrate material leaving the feed table into an upwardly concave curvature by which a succeeding length of such material is prevented from overrunning said length and is caused to establish edgewise abutting relationship therewith.

10. In a machine in which discrete lengths of a material on the order of paperboard are moved in one direction along a defined path past a processing station, means for establishing such lengths of material in edge-to-edge abutting relationship and for carrying them along said path in such relationship, said means comprising:

A. a flat endless belt;

B. roller means around which the belt is trained with a straight stretch thereof uppermost and extending along said path and by which the belt is driven for movement of said stretch in said direction;

C. a feed table having a surface which is substantially parallel to, but at a level above, said stretch of the belt, and which extends in said direction to an edge near said stretch and substantially transverse thereto;

D. means for advancing lengths of material in said direction along said surface of the feed table and by which such lengths are yieldingly urged in said direction at a speed which tends to be faster than the speed of said stretch of the belt; E. hold-down finger means above said stretch of the belt and spaced in said direction from said edge, said holddown finger means being arranged to engage each advancing length of material at a portion thereof that is between its side edges, and to force the same down into tractive engagement with said stretch of the belt; and F. means providing a pair of elongated rails which extend lengthwise in said direction from said edge on the feed table and which are spaced laterally of the belt to opposite sides of the hold-down finger means, said rails having surfaces substantially coplanar with said surface on said table, which surfaces on the rails support side edge portions of a length of material engaged by the hold down finger means and cooperate with the latter in imparting an upwardly concave curvature to the length of material that prevents overrunning of it by a succeeding length of material and establishes the latter in edgewise abutting engagement with it. 11. The machine of claim 10, further characterized by: G. the belt having numerous apertures therethrough; and H. a grid-like air intake disposed beneath said stretch of the belt for flatwise supporting engagement by the same, said air intake being connectable with a source of suction for drawing air through the apertures in the belt to thus suck lengths of material on said stretch into tractive engagement therewith. 12. in a machine in which discrete lengths of a material on the order of paperboard are moved in one direction along a defined path past a processing station, and which machine must at different times accommodate lengths of such material that are of different widths, means for transporting such lengths of material along said path, comprising:

A. an endless belt having broad inner and outer surfaces and having a plurality of apertures therethrough, each of which apertures is defined by l. an elongated lengthwise extending groove opening to the outer surface of the belt, and

2. a smaller hole opening to the bottom of the groove and to the inner surface of the belt, said apertures being centered on a plurality of laterally spaced lines that extend parallel to the edges of the belt;

B. roller means around which the belt is trained and by which it is driven, providing a straight upper stretch of the belt which extends along said path and moves in said direction;

C. an air intake comprising an element having an upper surface by which said stretch of the belt is supportingly engaged, said air intake having 1. grooves opening to its said upper surface and extending in said direction, said grooves being longitudinally centered on lines spaced in correspondence to said lines upon which the apertures in the belt are centered so that said apertures register with the grooves, and

2. a bore through said element, extending transversely to said grooves therein and opening to each of them, one end of said bore being connectable with a suction source so that suction can be applied to lengths of material on said stretch of the belt, to suck them into tractive engagement with the belt, through grooves in the air intake that are communicated with said bore and apertures in the belt that register with said grooves; and

D. a rod-like plug receivable in the bore from the other end thereof to block communication between the bore and a selected number of grooves in the air intake, so that air is not drawn through apertures in the belt that are to one side of lengths of material being transported thereon.

13. The machine of claim 12, further characterized by: said belt having other apertures therein, nearer the edge thereof that is adjacent to the first mentioned end of the bore in the air intake, each of said other apertures being defined by 1. an elongated groove opening to the outer surface of the belt and extending transversely to the belt edges, and

2. a smaller hole opening to the bottom of each of said other grooves and to the inner surface of the belt,

the last mentioned holes being centered on a line parallel to the edges of the belt to register with the groove in the air intake that is nearest said first mentioned end of the bore.

14. The machine of claim 13, wherein said processing station comprises means for applying molten thermoplastic to the lengths of material being processed, further characterized by:

each of said transverse grooves in the belt having a locally

Claims

1. In a packaging machine having a plurality of stations along a defined path, at one of which heated thermoplastic material is applied to substrate material and articles disposed thereon to form a film over each article and a portion of the substrate top surface that surrounds it, means for advancing substrate material with articles thereon from one to another of said stations and for applying suction to the bottom of the substrate material to suck the film down into snug engagement with the articles and the top surface of the substrate, the last named means comprising: A. a vacuum table which has 1. an upwardly facing stationary top surface that is interrupted by a plurality of spaced apart air inlet openings which collectively form a station-ary air intake, and 2. manifold means communicating with said openings; B. an endless flat belt having an upper stretch which flatwise overlies and slides lengthwise across said stationary top surface of the vacuum table, said belt having apertures therethrough which register with said stationary air inlet openings as the belt travels across the vacuum table; and C. means for applying suction to said manifold means, which suction is applied to substrate material riding on the belt as the apertures in the belt are brought into communication with said stationary air inlet openings, to cause the substrate material to tractively adhere to the upper stretch of the belt for advancement therewith and to draw air through the substrate material and thus evacuate the space beneath film thereon.

2. manifold means communicating with said openings; B. an endless flat belt having an upper stretch which flatwise overlies and slides lengthwise across said stationary top surface of the vacuum table, said belt having apertures therethrough which register with said stationary air inlet openings as the belt travels across the vacuum table; and C. means for applying suction to said manifold means, which suction is applied to substrate material riding on the belt as the apertures in the belt are brought into communication with said stationary air inlet openings, to cause the substrate material to tractively adhere to the upper stretch of the belt for advancement therewith and to draw air through the substrate material and thus evacuate the space beneath film thereon.

2. The packaging machine of claim 1, further characterized by means adapting the machine for use with discrete lengths of substrate material, the last mentioned means comprising: D. means defining a feed table having its discharge end substantially over the upstream end of the top stretch of the belt; E. means for successively feeding discrete lengths of substrate material along said feed table off its discharge end and towards the belt at a speed which tends to be faster than that at which the top stretch of the belt travels; and F. mEans at the discharge end of the feed table for imparting a transversely bowed shape to the trailing end of each length of substrate material as it leaves the feed table by which the next successive length of substrate material is prevented from overlapping it and is thus forced into edgewise abutting relation to it.

2. a smaller hole opening to the bottom of the groove and to the inner surface of the belt, said apertures being centered on a plurality of laterally spaced lines that extend parallel to the edges of the belt; B. roller means around which the belt is trained and by which it is driven, providing a straight upper stretch of the belt which extends along said path and moves in said direction; C. an air intake comprising an element having an upper surface by which said stretch of the belt is supportingly engaged, said air intake having

2. a bore through said element, extending transversely to said grooves therein and opening to each of them, one end of said bore being connectable with a suction source so that suction can be applied to lengths of material on said stretch of the belt, to suck them into tractive engagement with the belt, through grooves in the air intake that are communicated with said bore and apertures in the belt that register with said grooves; and D. a rod-like plug receivable in the bore from the other end thereof to block communication between the bore and a selected number of grooves in the air intake, so that air is not drawn through apertures in the belt that are to one side of lengths of material being transported thereon.

2. a smaller hole opening to the bottom of each of said other grooves and to the inner surface of the belt, the last mentioned holes being centered on a line parallel to the edges of the belt to register with the groove in the air intake that is nearest said first mentioned end of the bore.

3. The packaging machine of claim 2, wherein said means for imparting a bowed shape to the trailing end of each length of substrate comprises: G. substantially parallel longitudinal supports at the discharge end of the feed table spaced apart transversely of the belt and forming extensions of the feed table substantially parallel to the top surface of said stretch of the belt but elevated above the same; and H. hold down means between said spaced apart longitudinal supports for forcing a medial portion of the substrate material downwardly below the level of said longitudinal supports.

5. The packaging machine of claim 1, wherein said stationary inlet air openings in the top surface of the vacuum table comprise lengthwise extending transversely spaced grooves opening to its upwardly facing surface, and wherein said manifold means comprises: A. a transverse bore intersected by said grooves and communicable at one end with a source of suction; B. a plug axially slidable in said bore to block communication between a selected number of said grooves and the source of suction to thereby adapt the vacuum table to different widths of substrate material without loss of suction; and C. plug adjusting means connected to the plug and protruding from the other end of the bore.

6. In a packaging machine in which substrate material and articles to be packaged that are disposed thereon are carried in one direction along a defined path past a station at which heated thermoplastic material is applied to the articles and the substrate material to form a film over the same, means for moving substrate material along said defined path and for sucking film down into snug engagement with each article and with its surrounding portion of the substrate material, the last mentioned means comprising: A. a flat endless belt which is at least as wide as the substrate material and which has apertures therethrough at longitudinally and laterally spaced intervals; B. roller means around which the belt is trained with a straight stretch thereof uppermost and extending along said defined path and which drives the belt for movement in said direction; and C. air intake means between the roller means, having a stationary apertured top surface along which the upper stretch of the belt extends and with which it has intimate flatwise supporting engagement, the apertures in said surface of the air intake means being so arranged that the apertures in the belt register with them to enable air to be drawn into the air intake means through the apertures in the belt and through substrate material on the belt.

7. The packaging machine of claim 6, further characterized by: said apertures in the belt being defined by grooves in the outer surface of the belt, and holes through the bottom of at least some of the grooves.

9. The packaging machine of claim 6, further characterized by means adapting the machine for use with discrete lengths of substrate material, the last mentioned means comprising: A. a feed table having its discharge end substantially over the upstream end of said stretch of the belt; B. hold down means adjacent to the discharge end of the feed table and above the receiving end portion of said stretch of the belt to urge the lengths of substrate material into tractive engagement with said stretch of the belt as they leave the feed table; and C. longitudinally extending horizontal supports spaced laterally of the belt to opposite sides of the hold down means and substantially coplanar with the feed table to cooperate with the hold down means to flex the trailing end portion of each length of substrate material leaving the feed table into an upwardly concave curvature by which a succeeding length of such material is prevented from overrunning said length and is caused to establish edgewise abutting relationship therewith.

10. In a machine in which discrete lengths of a material on the order of paperboard are moved in one direction along a defined path past a processing station, means for establishing such lengths of material in edge-to-edge abutting relationship and for carrying them along said path in such relationship, said means comprising: A. a flat endless belt; B. roller means around which the belt is trained with a straight stretch thereof uppermost and extending along said path and by which the belt is driven for movement of said stretch in said direction; C. a feed table having a surface which is substantially parallel to, but at a level above, said stretch of the belt, and which extends in said direction to an edge near said stretch and substantially transverse thereto; D. means for advancing lengths of material in said direction along said surface of the feed table and by which such lengths are yieldingly urged in said direction at a speed which tends to be faster than the speed of said stretch of the belt; E. hold-down finger means above said stretch of the belt and spaced in said direction from said edge, said hold-down finger means being arranged to engage each advancing length of material at a portion thereof that is between its side edges, and to force the same down into tractive engagement with said stretch of the belt; and F. means providing a pair of elongated rails which extend lengthwise in said direction from said edge on the feed table and which are spaced laterally of the belt to opposite sides of the hold-down finger means, said rails having surfaces substantially coplanar with said surface on said table, which surfaces on the rails support side edge portions of a length of material engaged by the hold-down finger means and cooperate with the latter in imparting an upwardly concave curvature to the length of material that prevents overrunning of it by a succeeding length of material and establishes the latter in edgewise abutting engagement with it.

11. The machine of claim 10, further characterized by: G. the belt having numerous apertures therethrough; and H. a grid-like air intake disposed beneath said stretch of the belt for flatwise supporting engagement by the same, said air intake being connectable with a source of suction for drawing air through the apertures in the belt to thus suck lengths of material on said stretch into tractive engagement therewith.

12. In a machine in which discrete lengths of a material on the order of paperboard are moved in one direction along a defined path past a processing station, and which machine must at different times accommodate lengths of such material that are of different widths, means for transporting such lengths of mateRial along said path, comprising: A. an endless belt having broad inner and outer surfaces and having a plurality of apertures therethrough, each of which apertures is defined by

13. The machine of claim 12, further characterized by: said belt having other apertures therein, nearer the edge thereof that is adjacent to the first mentioned end of the bore in the air intake, each of said other apertures being defined by

14. The machine of claim 13, wherein said processing station comprises means for applying molten thermoplastic to the lengths of material being processed, further characterized by: each of said transverse grooves in the belt having a locally raised portion rising from its bottom, intermediate its ends, so that thermoplastic which unintentionally may accumulate on the belt and harden into a thin ribbon with an undulated formation caused by the transverse grooves, has bridging ribs formed therein across the undulations, which ribs prevent the undulated ribbon of hardened thermoplastic from stretching accordion-wise as it is stripped off the belt.