US3611885A

US3611885A - Compressing apparatus for container forming machine

Info

Publication number: US3611885A
Application number: US4189A
Authority: US
Inventors: Gerald C Paxton
Original assignee: SWF Companies Inc
Current assignee: SANGER WORKS FACTORY Inc A CORP OF; SWF Companies Inc
Priority date: 1970-01-20
Filing date: 1970-01-20
Publication date: 1971-10-12
Anticipated expiration: 1988-10-12

Abstract

An improved compressing apparatus for a container-forming machine providing a frame adapted to position a planar foldable container blank in a substantially planar assembly position with a pair of separate end panels disposed in substantially rightangular relation thereto and including coacting mandrel and die means on the frame operably concurrently to thrust the blank and the end panels through a substantially rectilinear path in a direction normal to the plane of the blank so as to fold the blank about the end panels in a container-forming position with the overlapping portions thereof providing at least one glued surface therebetween. The improvement of the present invention provides blank-compressing means mounted in fixed position on said die means in tightly pressing relation to said folded, overlapping portions of the blank and said end panels during said thrusting operation of the mandrel and die means.

Description

United States Patent 3,456,563 7/1969 Roesner et al.

ABSTRACT: An improved compressing apparatus for a container-forming machine providing a frame adapted to position a planar foldable container blank in a substantially planar assembly position with a pair of separate end panels disposed in substantially right-angular relation thereto and including coacting mandrel and die means on the frame operably concurrently to thrust the blank and the end panels through a substantially rectilinear path in a direction normal to the plane of the blank so as to fold the blank about the end panels in a contamer-forming position with the overlapping portions thereof providing at least one glued surface therebetween. The improvement of the present invention provides blank-compressing means mounted in fixed position on said die means in tightly pressing relation to said folded, overlapping portions of the blank and said end panels during said thrusting operation of the mandrel and die means.

PATENIED um 1 219?] SHEEI 3 OF 3 //6 xko GERALD C. PAXTON IN VE N 70/? 04 A 7'TORNEYS COMPRESSING APPARATUS FOR CONTAINER FORMING MACHINE CROSS-REFERENCE TO RELATED APPLICATIONS The present invention generally relates to the containerforming art and is particularly adapted for use with the container-forming machine shown in copending application Ser. No. 757,581 filed Sept. 5, I968 entitled Method and Machine for Forming Containers.

BACKGROUND OF THE INVENTION The above designated copending application discloses a container-forming machine which has been proven ideally suited for the intended purpose and has enjoyed substantial commercial success. It was recognized, however, that certain improvements'could be made to the structure thereof for greater simplicity and ease of operation particularly with respect to the container compressing and forming portion of the machine; The prior machine employed coacting mandrel and die means which were effective partially to fold the container blank in overlapping relation to the end panels of the container to be formed with the die means mounting a pair of opposite laterally movable compressing plates for completing the folding operation and adhesively bonding the blank to the end panels. Such movement had to be precisely synchronized with the termination of the initial thrusting movement of the mandrel and container forming blank into the die means and then subsequently retracted to permit withdrawal of the mandrel from the formed container and die means. This required a relatively large number of moving parts susceptible to wear and a complicated control system for such synchronized operation. It was, therefore, recognized that the forming operation and the structure of the machine could be greatly simplified if it were possible to form the container with a single-thrusting movement of the mandrel into the die means thus eliminating the additional lateral compressing operation.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved compressing apparatus for a containerforrning machine.

Another object is to provide such an improved compressing apparatus capable of fully forming a container by a singlethrusting movement of a blank-conveying mandrel into a die structure without requiring any additional lateral compressing operations.

Another object is to provide an improved compressing apparatus of the character described which is adapted successively to form a relatively large number of containers in a rapid, reliable manner.

Another object is to provide an improved compressing apparatus in which the previously formed containers are automatically ejected during each successive forming operation.

Another object is to provide an improved compressing apparatus which employs a coacting mandrel and die structure which is adapted successively to receive container-forming blanks and separate end panels having predetermined glue carrying portions in a substantially upright position in order to conserve floor space with the mandrel being effective to force the assembled blanks and end panels into the die structure past a plurality of preliminary blank-folding cams and plows on the die structure foldably to overlap the glued areas of the blanks and end panels with the die means providing a plurality of final compressing rollers disposed in freely rotating substantially frictionless compressing engagement with the overlapping portions of the blank and end panels for adhesively bonding them in container-forming relation.

Other objects and advantagesof the present invention will subsequently become more-clearlyapparent upon reference to the following description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of a compressing apparatus for a container-forming machine embodying the principles of the present invention.

FIG. 2 is a longitudinal vertical sectionrthrough the compressing apparatus, taken generally along the line 22 of FIG. )1.

FIG. 3 is an end elevation of the compressing apparatus of the present invention with portions broken away for illustrative convenience.

FIG. 4 is a somewhat enlarged, fragmentary, horizontal section through the mandrel and die means disposed in a container forming position.

FIG. 5 is a perspective view of the mandrel and die means with a finished container disposed therein and with the mandrel retracted from the die means.

FIG. 6 is a perspective of a container-forming blank prior to its introduction into the compressing apparatus of the present invention.

FIG. 7 is a perspective of an alternative type of container which is adapted to be produced by the compressing apparatus of the present invention without any modification thereto.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the drawings, a compressing apparatus embodying the principles of theipresent invention is disclosed for use with a container-forming machine of the type shown and described in copending application Ser. No. 757,581. The compressing apparatus provides a reciprocal substantially rectangular boxlike mandrel 10 which operationally coacts with a similarly shaped die 12 havinga mandrel-receiving compression chamber 14 therein. With the mandrel disposed in its retracted position of FIGS. l-and 2, there is formed a container blank assembly station 16 between the mandrel and the die into which a substantially flat con.- tainer fonning blank, such as that indicated by the reference numeral 18 in FIG. 6, is adapted to be disposed in a substantially upright position. A pair of transversely opposed end panel feed magazines 20, having a plurality of end panels 21 loaded thereon, are individually disposed on opposite sides of the mandrel for assembly with the container-fonning blank 18 in the assembly station 16.

As best shown in FIG. 6, the container-forming blank is of predetermined planar configuration and has a central main body portion 25 having opposite top andbottom side panels 26 and 27, respectively, foldable with respect to the body portion along scored lines 29. The top and bottom side panels individually include opposite

end gluing flaps

32 and 34, respectively, which are foldable from the panels along scored

lines

36 and 37, respectively. The

end gluing flaps

32 and 34 respectively provide inner

beveled ends

38 and 39 in angularly outwardly extended relation from their respective scored lines 29. The main body portion 25 also has opposite end gluing flaps 42 having opposite beveled ends 43 fonning with their respectively adjacent beveled ends of the end gluing flaps of the top and bottom side panels triangular-shaped notches 45 in the opposite edges of the container-forming blank 18.

The mandrel l0 and die I2 of the present invention are mounted upon a base 50 having a plurality of crossmembers, one of which is indicated by the reference numeral 52. A pair of elongated support rails 55 are mounted on the crossmembers 52 in substantially right angular relation thereto and in spaced substantially parallel relation to eachother. The spacing between the support rails is determinedby an elongated spacer bar 56 secured to the cross member 52by a pluralityof screw-threaded bolts 57 extended therethrough. Oppositeend bolts 58 are extended throughthesupport rails and .endwardly into the spacer bar to maintain the support rails in their desired spaced relation. It will be noted thatdifi'erent length spacer bars can be employed to vary the spacingbetween the support rails.

The die 12 is mounted on the support rails of the base 50 and generally provides a substantially rectangular open frame having a forward blank-receiving end 62 and an opposite rearward open container discharge end 63. The die frame includes forwardly and rearwardly disposed substantially rectangular chamber-forming

supports

65 and 66, respectively, disposed in substantially upright spaced relation on the support rails 55. The forward and rearward supports are substantially identical and individually provide a lower crossmember having opposite segmented ends 72 bolted to their respectively adjacent top surfaces of the support rails. The lower crossmembers include spaced inner ends 73 which are tied together by an elongated bridging strap 75 having a plurality of bolts 76 extended through elongated adjusting slots 77 therein.

Adjacent to each of the opposite ends 72 of the lower crossmember is mounted a substantially upstanding corner post 80 having a lower tubular sleeve 82 secured, as by welding or the like, to the crossmember and an opposite elongated upper rod 84 telescopically axially slidable within the lower sleeve. An annular collar 85 is disposed on the upper end of the lower sleeve and has a setscrew 86 mounted therein which is adapted to be tightened against the rod 84 of the corner post dependably to hold the rod in selected elevationally extended positions.

An upper crossmember 90 substantially identical to the lower crossmember 70 is mounted in bridging relation between the upper ends of the rod 84 of the oppositely disposed comer posts 80. The upper crossmember includes laterally spaced end sections 92 having outer ends 93 rigidly secured to the upper ends of the corner post rods and spaced inner ends 94 longitudinally adjustably connected by an elongated bridging strap 95. The bridging strap is rigidly secured in such position by a plurality of bolts 96 extended through elongated slots 97 in the strap.

The forward and rearward

supports

65 and 66 are intercon nected at each side of the die frame 60 by a pair of top and

bottom side rails

100 and 102, respectively, disposed inwardly adjacent to the comer posts 80 of the forward and rearward

supports

65 and 66. Each of the rails freely rotatably mounts a plurality of compression rollers having inner peripheries 106 disposed in a common plane laterally adjacent to the compression chamber 14 within the die 12. It will be noted that the top and bottom rails are substantially identical except that the top rails are inverted so that the rollers 105 are supported in depending relation therefrom.

A pair of sets of upper and lower panel camming straps 110 and 111, respectively, are mounted in forwardly extended relation from the die frame 60 in spaced, substantially parallel relation. Each of the camming straps has a rearward end 114 connected to its respectively associated upper and

lower crossmember

90 and 70 in edgewardly abutting relation to its associated top and

bottom rail

100 and 102. Each of the camming straps has a forwardly extended arcuately curved camming portion 116 outwardly curved away from the compression chamber 14 with the strap terminating in a rearwardly angularly extended forward end 118 providing a forward blank-engaging edge 120. As best shown in FIG. 2, the forward camming portions of the upper and lower camming straps arcuately outwardly diverge to funnel the containerforming blanks into the compression chamber.

A pair of sets of upper and lower flap folding plows are mounted on the forward ends of the top and

bottom rails

100 and 102, respectively, and provide outwardly contoured camming surfaces 127 for engaging the

end gluing flaps

32 and 34 of the top and bottom side panels 26 and 27 of the container blank 18. A pair of elongated substantially vertical com pression bars 130 having opposite upper and

lower ends

132 and 133, respectively, are slidably extended through

notches

135 and 136 in the rearward ends of the top and

bottom side rails

100 and 102. A locking bolt 138 is extended through the rearward end of the top side rails 100 and into their associated compression bars for dependably constraining the bars in their described positions. The lower ends of the compression bars are slidable through their respective notches in the bottom side rails during vertical adjustment of the forward and rearward supports 65 and 66 of the die frame 60. The compression bars individually include an inner compression surface 140 and a forwardly disposed beveled edge 142 for guiding the end gluing flaps of the container blank onto the inner surface.

A pair of laterally oppositely disposed substantially upright support posts are supported in upstanding relation from the inner surface of the support rails 55 of the base 50 on opposite sides of the container blank assembly station 16 between the mandrel 10 and the die 12. Each of the posts has a forward surface 152 connected in supporting relation, as by welding or the like, to its respectively associated end panel magazine 20 and an opposite rearward surface 153. Each of the posts includes an inner surface 155 which mounts an elongated blank-guiding strip 157 having a lower end 158 terminating in a plane disposed well below the top side rails 100 of the die frame 60.

A pair of elongated container-stripping plates 160 are individually disposed along the opposite sides of the die frame 60 substantially intermediate the top and

bottom side rails

100 and 102. Each of the stripping plates has a forwardly disposed shoe mounting end 162 having opposite angularly extended container camming ends 164 with the shoe being mounted on the rear surface 153 of its respectively associated support post 150. Each of the stripping plates includes an opposite distal end 166 which is angularly inwardly bent for extension into the compression chamber 14 within the die frame 60. The distal end includes a substantially straight edge 168 which is engageable with the end gluing flap 42 of the main body portion 25 of the container blank 18.

The mandrel 10 of the present invention is reciprocably mounted on the base 50 for movement from its retracted position of FIGS. 2 and 5 to a compressing position disposed within the compression chamber 14 of the die frame 60 as shown in FIG. 3. The mandrel provides a substantially rectangular frame which, as best shown in FIG. 3, is of a somewhat smaller size than the compression chamber 14 and has a plurality of angle iron corner beams 170 transversely interconnected by a plurality of tubular cross rods 172. A plurality of inwardly disposed plates 173 are individually mounted on the comer beams to support thcrebetween vertically disposed sideplates 175. A centrally disposed cross rod 176 is extended between the sideplates and pivotally mounts an elongated push arm 178 connected at its opposite end to a reciprocating power source, not shown, on the container-forming machine. A pair of upper and lower end panel feed bars 180 have forward edges 182 for engaging the rearward edge of the forwardmost end panel 21 on the magazines 20. The feed bars are adjustably mounted on their respective comer beams 170 by a plurality of bolts 183 extended through elongated slots 185 therein in order to adjust for different sizes of end panels.

An alternate form of container, generally indicated by the reference numeral in FIG. 7, may also be formed in the compressing apparatus of the present invention without any modification thereto. Such container is of the type employed as a fruit packing tray having relatively shallow top and

bottom sidewalls

192 and 193, respectively, and opposite sidewalls 194. The top and bottom walls include end gluing flaps 196 which are folded around the comers of the container in overlapping bonded relation to the opposite sidewalls.

OPERATION The operation of the described embodiment of the subject invention is believed to be clearly apparent and is briefly summarized at this point. The carton-forming blank 18 is extended downwardly through a substantially rectilinear path of travel into the assembly station 16 between the mandrel 10 and the die 12 by a blank propelling and flap gluing section of the machine, not shown, which is fully described and shown in the above designated copending application. The container blank is guided downwardly between the support posts 150 against the guide strips 157 thereon until the blank is substantially centered in the position shown in FIG. 2 with the upper and lower edges thereof extended somewhat beyond their respectively adjacent forward edges 120 of the upper and lower camming straps 110 and 111. During such downward movement of the blank to the position of FIG. 2, cocking of the blank into the compression chamber 14 within the die frame 60 is precluded by the upper angular end of the shoes 162 of the stripping plates 160.

Upon full deposit of the container-forming blank 18 into the assembly station 16, the push arm 178 is effective to propel the mandrel in a substantially horizontal direction of movement from left to right, as viewed in FIGS. 2 and 5, for engagement with the container-forming blank. During such initial movement of the mandrel, the end panel feed bars 180 engage the rearward edge of the forwardmost end panel 21 on the magazines 20 to position the end panels in edgeward engagement with the container-forming blank 18. Upon continued movement of the mandrel, the top and bottom side panels 26 and 27 of the container-forming blank engage the arcuate forward end portions 116 of the camming straps preliminarily to fold them inwardly toward the upper and lower ends of the end panels 21. At the same time, the end gluing flaps 42 of the main body portion 25 of the blank are folded inwardly toward the end panels by engagement with the stripping plates 160.

As the mandrel l0 continues inwardly into the compression chamber 14 within the die frame 60, the end gluing flaps 32 and 34 of the top and bottom side panels 26 and 27, respectively, engage their respectively associated folding plows 125 for preliminary folding of them toward the end panels 21. Upon further movement of the mandrel, the end gluing flaps 32 and 34 engage the inner peripheries 106 of the compression rollers 105 on the top and bottom side rails 100 and 102 with the rollers providing substantially frictionless compression of the end gluing flaps in tightly bonding relation to the end panels 21 against the sideplates 175 of the mandrel. Accordingly, each of the end flaps is continually compressed upon successive engagement with the series of rollers for insuring a dependable bond between the flaps and the end panels.

As the mandrel l0 approaches the discharge end 63 of the die frame 60, the end gluing flaps 42 on the main body portion 25 of the container blank are folded inwardly against the end panel 21 by the angular distal ends 166 of the stripping plates 160. Such end flaps then engage the beveled forward edges [42 of the compression bars 130 which guide the flaps between the compression bars and the adjacent end panels 2]. ln such position, the distal ends 166 of the stripping plates are permitted to spring inwardly against the end panels in a position edgewardly to engage the end flaps 42. The mandrel 10 is retracted from the compression chamber 14 with the stripping plates 160 being effective to hold the formed container within the discharge end of the die frame 60. The newly formed container remains in such position until the next container-forming blank 18 is thrust into the compression chamber by the mandrel which engages and automatically ejects the preceding container from the rearward discharge end 63 of the die frame.

The alternate tray-type container 190 of FIG. 7 is formed in substantially the same manner as that described during the formation of the container from the blank 18 of P16. 6. ln such operation, the top and

bottom walls

192 and 193 are folded upon engagement with the upper and lower camming straps 110 and 111, respectively; the sidewalls 194 are folded by the stripping plates 160 and subsequently compressed by the compression bars 130; and the end flaps 196 are initially folded by the plows 125 and compressed in tightly bonding relation against the sidewalls 194 by the compression rollers 105.

In view of the foregoing, it is readily apparent that the structure of the present invention provides an improved compressing apparatus for a container-forming machine which is effective fully to form a container therein with a single thrust of the mandrel into the compression chamber of the die frame without any separate lateral compressing operations. The im' proved compressing apparatus is adapted successively to form a relatively large number of containers in a wide varietyof sizes and in a rapid and reliable manner with the newly formed containers therein being automatically ejected upon the formation of succeeding containers.

Although the invention has been herein shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures maybe made therefrom within the scope of the invention, which is not to be limited to the illustrative details disclosed.

Having described my invention, what I claim as new'and desire to secure by Letters Patent is:

1. In a container-forming apparatus including a coacting mandrel and die means having a compressing compartment and in which the mandrel is reciprocated to and from the compartment to thrust foldable container blank means into the compartment in a predetermined direction whereby the die means folds a portion of the blank means constituting a gluing flap back over another portion of the blank means to which the flap is to be secured and to retract from the die means; an elongated container-stripping plate having a mounting end secured in fixed relation to the die means and a flexible distal end extended from the mounting end in the direction of movement of the mandrel into the compartment to engage the gluing flap to fold it against said another portion, said distal end having a container-stripping edge movable inwardly against said another portion of the blank means upon movement of said gluing flap therepast and being edgewardly engageable with said gluing flap to preclude return movement of the formed container upon retraction of the mandrel from the compartment.

2. ln an apparatus for forming a container providing a frame adapted to position a planar foldable container blank in a substantially planar assembly position with a pair of separate end panels disposed in substantially right-angular relation thereto and including coacting mandrel and die means on the frame operable concurrently to thrust the blank and the end'panels through a substantially rectilinear path in a direction normal to the plane of the blank so as to fold the blank about the end panels in a container-forming position with the overlapping portions thereof providing at least one glued surface therebetween; the improvement comprising blank-compressing means mounted in fixed position on said die means in tightly pressing relation to said folded overlapping portions of the blank and said end panels during said thrusting operation of the mandrel and die means, said container blank having a main body portion and opposite top and bottom side panels foldable therefrom and said body portion and side panels having foldable end gluing flaps disposable in overlapping relation to said end panels with said compressing'means on said die means foldably pressably engaging said end gluing flaps on said side panels against the end panels; combination flap folding, compressing, and retaining means on said die means concurrently foldably engaging said end gluing flaps of said main body portion toward and against said end panels and restraining return movement of the container formed within said die means along said path during subsequent separation of said mandrel and die means, said die means including a substantially rectangular frame having opposite sets of top and bottom side rails laterally interconnected in circumscribing relation to a blank compressing chamber therein, said mandrel providing a substantially rectangular blank-thrusting frame having spaced substantially parallel sides-reciprocal between said container forming position disposed within said'blankcompressing chamber of the die means and said blank assembly position retracted from the compressing chamber with said mandrel-including means on said sides thereof for feeding said end panels into said compressing-chamber with the container blank, said compressing means being mounted in fixed position on said top and bottom side rails of the die means in closely spaced relation to said sides of the mandrel when the latter is disposed within said compressing chamber in tightly compressing relation to said end gluing flaps of the top and bottom side panels of the container blank and the portions of the end panels overlapped thereby, said compressing means including a plurality of sets of rollers individually freely rotatably mounted along said top and bottom side rails of the die means with the rollers of each set having inner peripheries disposed substantially tangentially to a common plane mar ginally along said compressing chamber in substantially frictionless rolling compressing relation to said end gluing flaps of the top and bottom side panels; a plurality of contoured flap plows individually mounted on said top and bottom side rails of the die means within said path of the container blank into said compressing compartment ahead of their respectively adjacent sets of compressing rollers initially to engage and to fold said end gluing flaps of the top and bottom side panels inwardly toward their associated end panels; and an elongated substantially flat container-stripping plate having a mounting end secured to said die means in longitudinally extended relation substantially intermediate each of said top and bottom side rails and an opposite flexible distal end angularly inwardly extended into said compressing compartment past said plane of the rollers for folding its respectively associated end gluing flap of the main body portion of the container blank inwardly toward its respectively associated end panel, said distal end having a container-stripping edge movable inwardly against said end panel upon movement of said end gluing flap therepast and being edgewardly engageable with said end gluing flap of the main body portion of the container blank to preclude return movement of the formed container along said path during retraction of said mandrel from said compressing compartment of the die means.

3. The improvement of claim 2 wherein said formed container is automatically ejected from the die means by movement in the same direction as when formed by the introduction of a succeeding container blank into said compressing compartment.

4. The improvement of claim 2 in which said combination flap folding, compressing, and retaining means further includes an elongated substantially upright flap compressing bar mounted on said die means between each of said top and bottom side rails in closely spaced adjacent relation to its respectively adjacent side of the mandrel when the latter is disposed within the compressing compartment in compressing relation to its respectively adjacent end flap of the main body portion of the container blank.

5 The improvement of claim 4 including extendibleretractable support means interconnectably vertically extended between the top and bottom side rails of each set of side rails at the opposite sides of said die means, and extendi ble-retractable means interconnectably longitudinally extended between the corresponding pairs of top and bottom side rails at the opposite sides of the die means adjustably to vary the size of said compressing compartment for forming various sizes of containers therein.

Claims

2. In an apparatus for forming a container providing a frame adapted to position a planar foldable container blank in a substantially planar assembly position with a pair of separate end panels disposed in substantially right-angular relation thereto and including coacting mandrel and die means on the frame operable concurrently to thrust the blank and the end panels through a substantially rectilinear path in a direction normal to the plane of the blank So as to fold the blank about the end panels in a container-forming position with the overlapping portions thereof providing at least one glued surface therebetween; the improvement comprising blank-compressing means mounted in fixed position on said die means in tightly pressing relation to said folded overlapping portions of the blank and said end panels during said thrusting operation of the mandrel and die means, said container blank having a main body portion and opposite top and bottom side panels foldable therefrom and said body portion and side panels having foldable end gluing flaps disposable in overlapping relation to said end panels with said compressing means on said die means foldably pressably engaging said end gluing flaps on said side panels against the end panels; combination flap folding, compressing, and retaining means on said die means concurrently foldably engaging said end gluing flaps of said main body portion toward and against said end panels and restraining return movement of the container formed within said die means along said path during subsequent separation of said mandrel and die means, said die means including a substantially rectangular frame having opposite sets of top and bottom side rails laterally interconnected in circumscribing relation to a blank compressing chamber therein, said mandrel providing a substantially rectangular blank-thrusting frame having spaced substantially parallel sides reciprocal between said container forming position disposed within said blank-compressing chamber of the die means and said blank assembly position retracted from the compressing chamber with said mandrel-including means on said sides thereof for feeding said end panels into said compressing chamber with the container blank, said compressing means being mounted in fixed position on said top and bottom side rails of the die means in closely spaced relation to said sides of the mandrel when the latter is disposed within said compressing chamber in tightly compressing relation to said end gluing flaps of the top and bottom side panels of the container blank and the portions of the end panels overlapped thereby, said compressing means including a plurality of sets of rollers individually freely rotatably mounted along said top and bottom side rails of the die means with the rollers of each set having inner peripheries disposed substantially tangentially to a common plane marginally along said compressing chamber in substantially frictionless rolling compressing relation to said end gluing flaps of the top and bottom side panels; a plurality of contoured flap plows individually mounted on said top and bottom side rails of the die means within said path of the container blank into said compressing compartment ahead of their respectively adjacent sets of compressing rollers initially to engage and to fold said end gluing flaps of the top and bottom side panels inwardly toward their associated end panels; and an elongated substantially flat container-stripping plate having a mounting end secured to said die means in longitudinally extended relation substantially intermediate each of said top and bottom side rails and an opposite flexible distal end angularly inwardly extended into said compressing compartment past said plane of the rollers for folding its respectively associated end gluing flap of the main body portion of the container blank inwardly toward its respectively associated end panel, said distal end having a container-stripping edge movable inwardly against said end panel upon movement of said end gluing flap therepast and being edgewardly engageable with said end gluing flap of the main body portion of the container blank to preclude return movement of the formed container along said path during retraction of said mandrel from said compressing compartment of the die means.

5. The improvement of claim 4 including extendible-retractable support means interconnectably vertically extended between the top and bottom side rails of each set of side rails at the opposite sides of said die means, and extendible-retractable means interconnectably longitudinally extended between the corresponding pairs of top and bottom side rails at the opposite sides of the die means adjustably to vary the size of said compressing compartment for forming various sizes of containers therein.