US2921506A - Carton folding machine - Google Patents

Description

Jan. 19, 1960 A. JOHNSON CARTON FOLDING momma Filed Oct. 2'7. 1954 5 Sheets-Sheet 1 a ,t/GJ

Jan. 19, 1960 Filed Oct. 27. 1954 A. JOHNSON CARTON FOLDING MACHINE 5 Sheets-Sheet 2 INVENTOR. l4 Jam 5am Jan. 19, 1960 A. JOHNSON 2,921,505.

CARTONVFOLDING MACHINE Filed Oct. 27, 1954 5 Sheets-Shut 25 lllllllll JNVEN TOR. l4 Arm 1m Jan. 19,

Filed 001;.

A. JOHNSON CARTON FOLDING MACHINE 79 j! J [7/051 I? 11x55 7 5 Sheets-Sheet INVENTOR. l4 Joy/v50 A. JOHNSON CARTON FOLDING MACHINE Jan. 19, 1960 5 Sheets-Sheet 5 Filed Oct. 27. 1954 -FIG. 15

INVENTOR. I: Jam 5a lrraavn" United States Patent Oflice 2,921,506 Patented Jan. 19, 1960 CARTON FOLDING MACHINE Al Johnson, Stockton, Calif.

Application October 27, 1954, Serial No. 464,964

6 Claims. (CI. 93-51) The invention relates to machines for converting carton blanks into carton form, and especially to machines for folding-and forming carton blanks of the types known as roll-over end locks, and roll-over side locks.

It is an object of the invention to provide a carton folding machine which greatly increases the rate of carton forming over that obtainable by manual folding.

It is another object of the invention to provide a simple and inexpensive carton folding machine.

It is a further object of the invention to provide a carton folding machine which does not require, for its operation, any electrical connections or electrical energy source.

It is a still further object of the invention to provide a carton folding machine which requires but a small amount of floor space and which is compactly constructed.

It is a yet further object of the invention to provide a generally improved carton folding machine.

Other objects, together with the foregoing, are attained in the embodiment described in the accompanying description and illustrated in the accompanying drawings in which:

Figure 1 is a sectionalized side elevational view of the machine, the section being taken on a median, vertical longitudinal plane, the left-hand portion of the machine being considered, for convenience of descrition, the rear side of the machine, and the right-hand portion, the front side of the machine.

Figure 2 is a perspective view of a roll-over side lock carton blank.

Figure 3 is a perspective view of a formed carton.

Figure 4 is a partially sectioned rear elevational view of the machine, the plane of section being indicated by the line 4-4 of Figure 1.

Figure 5 is a section of the die and plunger taken along the plane generally indicated by the line 55 of Figure 4 but showing the plunger in a position below the plunger location shown in Figure 4, and showing a completed carton in position at the lower end of the die.

Figure 6 is a perspective view of a partially formed carton, the carton form substantially corresponding to the form of the carton shown partially folded about the plunger appearing in Figure 5.

Figure 7 is a sectional view of a portion of the lower end of the die showing a completed carton held in position by the carton supporting jaws and with the roll-over fingers moving upwardly in a direction away from the carton side, the plane of section being indicated by the line 7-7 of Figure 5.

Figure 8 is a partial sectional view, looking downwardly into the die, the plane of section being indicated by the line 8-8 of Figure 5.

Figure 9 is a section of the die and plunger on a plane substantially identical with the plane of section of Figure 5 but showing the plunger in a position below the plunger location appearing in Figure 5, and showing a completed carton being ejected from the lower end of the die.

Figure 10 is a perspective view of a partially-formed carton, the carton form corresponding to the form of the carton shown folded about the plunger appearing in Figure 9.

Figure 11 is a perspective of a completed carton, corresponding to the completed carton being ejected from the lower end of the die in Figure 9.

Figure 12 is a partial sectional view of the lower end of the die, the view corresponding to that of Figure 7, showing the completed carton being released by the supporting jaws and being ejected from the lower end of the die, and the roll-over fingers moving into fully retracted position, the plane of section being indicated by the line 1212 of Figure 9.

Figure 13 is an enlarged sectional view of the carton ejecting mechanism, the section being taken on the median vertical longitudinal plane indicated by the line 13-13 of Figure 7, a portion of the figure being broken away to reduce the extent of the figure.

Figure 14 is a partial median transverse sectional view of the lower end of the die, corresponding to the views shown in Figures 7 and 12 but with the plunger in lowermost or fully extended position, theroll-over fingers being in fully retracted position preparatory to swinging inwardly and downwardly into engagement with the roll-over lock panels of the carton.

Figure 15 is a view corresponding to that shown in Figure 14, but with the roll-over fingers in lock panel engaging position and swinging downwardly, other positions of the fingers and panel being shown in outline.

Figure 16 is a perspective view of a partially formed carton substantially corresponding to the carton form shown in Figure 15.

Figure 17 is a partial sectional View of the carton back panel bowing and stiffening members, the plane of section being indicated by the line 17-17 of Figure 8.

While the carton folding machine of my invention is susceptible of numerous physical embodiments, depending upon the particular environmental characteristics presented, a substantial number of the following described machines have been made and used, and have performed in an eminently satisfactory fashion.

The machine comprises a frame 21 having a pair of vertical spaced panels or supporting members 22, each conveniently provided with a pair of legs 23 supported on a floor 24 or other surface. Mounted on each of the supporting members 22 and extending vertically upwardly is a standard 26 surmounted by a block 27, the blocks being held in rigid spaced relation by a cross-bracing member 28 secured thereto. Each of the vertical standards has formed therein a vertical central slot 29 serving as a guide for a transverse plunger bar 31, whose opposite ends 32 extend into the corresponding slots 29 and which. translate upwardly and downwardly therein.

Securely mounted on the outer ends of the plunger bar 31 is a pair of arms 33 extending downwardly and having a length such that their lower ends 34 are at a predetermined location with respect to a pair of shock and sound cushioning stops 36 located at the lower end of a pair of vertical tracksv37, or slots, suitably formed in the frame to guidethe arms 33. As the arms 33 are urged downwardly by the exercise of downward force on the cross bar 31, the cushions 36 serve to stop or limit the downward movement of the arms to a predetermined desired amount. Downward motion is ordinarily produced by the operators muscular effort, the operator pushing downwardly on the plunger bar 31. It has been found, however, that in lieu of muscular effort a pneumatically or hydraulically actuated system (not shown) can be used with singular effectiveness on the machine, the cylinder manage being mounted vertically on top of the bracing member 28 and the piston rod extending downwardly through the bracing member and into engagement with the plunger bar or returning force provided by a suit,- ably chosen pair of tension springs 41 mounted at their upper ends inoutward extensions 42 of the bracing mernher 28 and .at their lower ends in a pair of brackets 43 seem d to h m 3- Mounted centrally on the plunger cross bar 31 and depending vertically therefrom is a plunger arm ,46 terminatingat its lower end in a plunger block 47, or shoe, having a flat bottom surface 45 and having formed therein, on the front and rear faces a pair of spaced vertical slots .48 and a somewhat wider median vertical slot 50 to avoid interference on the plunger return or up-stroke, between .the plunger shoe and certain members later to be described. The several plunger components are collectively designated as a plunger 49,, although, in most instances, the term plunger is used to mean the lower end of the arm, and especially to the plunger shoe 47.

The plunger is vertically movable into and through a die, generally designated by the numeral 51, the die being mounted on the frame 21 between the supporting members 22 and comprising a rear wall 52, a front wall 53 and a pair of substantially identical side walls 54 facing each other and being disposed, on each side of the machines median vertical longitudinal plane 55, in mirror symmetry. The four die walls include a. rear wall face 56, a front wall face 57 and a pair of side wall faces 58 bounding a vertically disposed die aperture 59, or opening, or throat, slightly larger in horiz'ontal cross-sectional dimension than the margins of the plunger shoe.

Preparatory to lowering the plunger, a carton blank 61 is placed, by the operator, in a location over the die, with an overhanging portion of the carton blank supported by a horizontal carton-supporting tray 62 suitably mounted on the frame and bounded on opposite sides by a pair of guide rails 60.

The carton blank 61 herein exemplified is typical of the roll-over side lock type and comprises a main or bottom panel 66 substantially coinciding in extent with the bottom face 45 of the plunger shoe. Connected to the bottom panel 66 along a score line 67 is a front panel 68, which is connected in'turn, along score lines 71, to a pair of laterally extending front panel retaining tabs 72, or flaps, or cars; likewise connected to the bottom panel 66, along a score line 73, is a rear panel 74, which in turn is connected along score lines 75 to a pair of laterally exending rear panel retaining tabs 76, or flaps, or cars. The rear panel 74 differs from the front panel 68, however, in that there is connected to the rear panel 74, along a score line 77, a top panel 78 having a top end flap 79 and a pair of top side flaps 80. It is to be noted that the herein-described carton folding machine does not fold the top flaps 79. and Si), nor is the top panel 78 caused to be bent about the score line 77. Instead, the carton is considered to be completely formed when it has been caused to assume the shape shown in Figure 3. The goods are most conveniently packaged when the carton is in the open form shown in Figure 3, the carton top being folded and tucked into closed carton position after the merchandise is placed in the box.

The carton blank also includes a pair of locking panels which, in the particular carton form here exemplified, are designated generally as side lock panels 81, each side lock panel including a side panel 82 connected along a score line 83 to the "bottom panel, and along a score line 84, in turn, to a roll-over panel 86, or curlpanel, and which is bent or folded inwardly and over the interfacing side panel 82 and inwardly bent retaining flaps 72 and 76, as appears most clearly in Figures 15 and 16. In order to hold the roll-over panel 86 in its fully bent over or folded position and to prevent the inherent resiliency of the rollover panel 86. material from acting, still another tab or flap is provided, the flap being termed a roll-over panel retaining flap 88 and which is scoredly connected to the roll-over panel 86 along a score line 89. As most clearly appears in Figures 3 and 15, the retaining flap 88 is bent inwardly during the folding operation so as to lie parallel with the bottom panel, and acts as a compression bracing member in holding the roll-over panel in a tight vertical position. This retaining effect is even more elfectively secured as the goods are packaged in the carton, the weight of the goods serving to hold the panel 86 and panel retaining flap 88 in sharp corner relation.

As the plunger shoe is urged downwardly into engagement with the bottom panel 66 the carton blank is also forced downwardly so that the bottom surfaces of the various carton panels and flaps are urged against various of the die surfaces to elfect appropriate folding. The first folding to be effected is the bending upwardly of the front and rear panel retaining flaps 72 and 76, respectively. As appears most clearly in Figure 4, a pair of sharply curved and facing shoulders 91 are formed on each of the upper surfaces of the die side walls, abutment of the flaps 72 and 76 against the shoulders 91 causing the flaps 7 2 and 76 to fold upwardly about the score lines 71 and 75 as hinges as the plunger shoes pushes downwardly against the main or bottom panel.

Slightly lower than the two pairs of shoulders 91 is an arcuately and inwardly curved front panel folding shoulder 92 and a similarly constructed but oppositely disposed rear panel folding shoulder 93, causing the front panel 68 and the rear panel 74, respectively, to fold upwardly and inwardly toward and into face to face relation with the front and rear faces of the plunger shoe. With especial reference to Figure 5, it will be seen that as the shoulders 92 and 93 engage and fold upwardly and inwardly the front and rear panels, the corresponding front and rear panel retaining flaps 72 and 76, previously folded to an upright position are swung inwardly and downwardly about the scored lines 67 and 73, respectively, as hinges, and so as to lie in face to face engagement with the sides of the plunger shoe.

As appears most clearly in Figure 4, a pair of side lock panel folding shoulders 96 are provided at the upper ends of the die side walls, and at a vertical position somewhat lower than the shoulders 92 and 93. Interposition of the side lock panels 81 between the shoulders 96 and the adjacent lower edges of the plunger shoe causes the side lock panels 81 to bend or fold upwardly and inwardly about the score lines 83 as hinges, as appears in Figures 6 and 10, and into face to face abutment with the outer sides of the corresponding retaining flaps 72 and 76.

Co-operation between the downwardly traveling plunger shoe and the various die shoulders, in the manner described, converts the flat carton blank into the carton or box form shown most clearly in Figure 10, the carton assunning this shape at approximately the same instant the bottom of the plunger shoe arrives at the location in the die indicated by the horizontal dotted line 99 in Figure 5.

At this juncture, the front lower edge of the carton, folded about and backed by the plunger shoe front lower margin, comes into engagement with the upper ends of a pair of front retaining, or supporting, jaw bars 101 mounted in a recess 102 in the die front wall so as to pivot inwardly and outwardly about a pin 103. Each of the frontretaining jaw bars 101 includes a vertically elongated and thickened central portion 104, or shank, having an inner edge 106 urged inwardly into the die opening by a compression spring 107 bearing inwardly against the bottom rear portion of the bar. The inner edge 106 is surmounted by an outwardly curving or faired portion 108, termed a jaw bar camming surface, and terminates at its lower end in an overhanging lip 111, with arecess 112, or mouth, or jaw being formed on the inner edge of the lower end of the bar, the mouth being defined at its lower end by an under-hanging or inwardly jutting lip 113. The lip 113 serves to support or retain a carton in lowermost position in the. die. as long as the jaw bar 101 is in the projected position shown for example, in Figure 5. Abutment between the vertical edge of the recess 112 and a transverse strap 114, or cleat, limits and stops inward jaw movement.

On the opposite, or rear, die wall a somewhat similar but oppositely facing pair of rear supporting jaw bars 116 is mounted in a pair of die recesses 117 to rock about a transverse pin 118, each jawbar having an inner projecting portion 119 surmounted by a jaw bar camming surface 121 and terminating at its lower end in an overhanging lip 122, a recessed jaw portion 123, and an underhanging supporting lip 124. A limit-stop strap 125, or cleat, defines the extent of inward movement of the jaw bar caused by a compression spring 126.

As appears most clearly in Figures 5 and 9, engagement of the carton-encompassed plunger shoe with the oppositely disposed jaw bar camming surfaces simultaneously urges the front and rear jaw bar pairs outwardly into retracted position, the supporting lips thereby being rendered ineffective further to support a previously formed and held carton 131 at the bottom of the die, and permitting the formed carton to be ejected downwardly and out of the die.

With especial reference to Figures 5, 8, 9 and 13, it is to be seen that positively acting mechanisms are provided to eject at the proper point in the cycle the formed carton 131 at the bottom of the die, the mechanisms acting in dependence upon the position and downward motion of the plunger as it descends with the subsequent carton folded about it, and in co-operation with the carton supporting or retaining jaws heretofore described.

The rear or back portion of the formed and ready to be ejected carton 131 is urged downwardly by reason of the abutment between the descending carton-covered plunger shoe base 45 and the uppermost edge of the top panel flap 79 on the formed carton 131, as illustrated in Figure 9. As shown most clearly in Figures 8, 9 and 17, the top panel 78 and top panel flap 79 are bowed inwardly over their middle portions by a pair of vertically spaced leaf springs 141 secured at their upper ends to the rear die wall face. The leaf springs are effective to bow the flap 79 and top panel 78 inwardly into the die aperture but are ineffective to deform inwardly the descending carton bottom panel since the descending carton is backed by the plunger shoe, or, rather, the carton material overlying the rear one of the vertical grooves 50 in the plunger is strong enough to deform the springs 141. As a result,

- furthermore, of the inward bow given to the top panel by the leaf springs, the vertically disposed top panel is given additional beam strength so that as the descending plunger shoe pushes downwardly on the top edge of the top panel, the top panel remains rigid and pushes downwardly in turn, on the carton until the carton is ejected from the die.

The front portion of the formed carton is concurrently pushed downwardly or ejected from the die as a consequence of the action of a carton ejecting or knock-out finger 146 disposed in a vertical recess 147 in the front die wall, as most clearly appears in Figures 4, 8 and 13. The knock-out finger 146 is pivotally mounted on a pin 148 and is swingable from an upper, normally retracted position, shown in full line in Figure 13, inwardly and downwardly into contact with the upper edge of the carton front panel, and downwardly to the lowermost position, shown in outline in Figure 13, pushing ahead of it, in a downward direction, the front portion of the carton. This knock-out action takes place at substantially the same instant the upper edge of the carton top panel at a higher elevation is engaged and urged downwardly by the descending plunger. This simultaneous action is effected by the provision of an actuating finger 151 disposed in the recess 147 at an appropriate elevation above that of the knock-out finger 146. The actuating finger 151 is pivotally mounted to swing about a pin 152 and is urged into uppermost position, in which position the finger projects partially into the die opening, as shown in full line in Figure 13, by a tension spring pivotally mounted on the actuating finger 151 by a pin 157, and on the knock-out finger 146 by a pin 158, causes the fingers to move in unison. Thus, as the descending plunger, that is to say, the carton material overlying the adjacent slot 50 in the plunger, abuts the projecting portion 159 of the actuating finger 151 and swings it downwardly and inwardly to the lowermost retracted position, shown in outline in Figure 13, the knock-out finger 146 is concurrently and similarly actuated, the knock-out finger pressing downwardly on the front panel of the carton and thereby effecting ejection of the front portion of the formed carton from the die in co-operation with the ejection of the rear portion produced by the plunger shoe.

Upon dislodgment, the formed carton falls by gravity onto an inclined surface 161, as shown in Figure 1, and slides outwardly onto the floor or into a receptacle (not shown) for appropriate disposition.

Upon ejecting the previously folded carton, the plunger shoe with the subsequent partly-formed carton folded about it continues to descend through the die. The carton overlies the vertical slots 48 in the plunger and since the beam strength of the carton material overlying the slots 48 exceeds the deforming force exerted by the springs 107 and 126 of the retaining jaws, the jaws 101 and 116 are cammed outwardly, as appears most clearly in Figure 9, as the carton material overlying the slots 48 comes into engagement with the cam surfaces 108 and 121 on the jaws. The front and rear retaining jaws return under spring urgency to innermost projected position as soon as the plunger top slides downwardly past the overhanging jaw lips 111 and 122. The plunger stroke is determined by the length of the arms 33, and by suitable arm adjustment, the lowermost position of the plunger is made to coincide with the position of the lower jaw lips 113 and 124, the carton being in abutment with the lower lips at the end of the plunger stroke, as appears in Figure 14. At this juncture the plunger springs 41 are permitted to retract the plunger upwardly, the vertical slots 48 on the plunger front and rear faces preventing interference between the shoe and the projecting shank portions 106 and 119 of the retaining jaw bars, and the slots 50 on the plunger shoe faces permitting the plunger shoe to translate upwardly without interfering with the actuating finger 151 on the front die face. On the downstroke, with the carton material overlying the rear one of the slots 50 in the plunger, the leaf spring members 141 are deformed outwardly by engagement with the carton material. On the upstroke, similar deformation of the leaf spring members 141 on the back die face occurs since the top panel 78 overlies the leaf springs 141 and the portion of the panel 78 spanning the rear slot 50 in the plunger is adequate to resist deformation by the springs. Once the plunger has cleared the springs 141, however, the springs cause the panel to bow inwardly, as previously explained.

As the plunger retracts or withdraws upwardly from the partly-formed carton supported in the retaining jaws, the carton is restrained against moving upwardly with the plunger, that is to say, the carton is stripped from the plunger. As most clearly appears in Figure 8, the side flaps of the vertically disposed top panel 78 of the carton remain in spread or open or transverse position, as heretofore explained, and are constrained to slide downwardly in a corresponding pair of vertical slots 176 between the die side walls 54 and the rear wall 52 as the plunger descends. The force exerted by the plunger against the carton bottom panel on the plunger downstroke is more than adequate to overcome the resistance offered by the surfaces or walls of the slots 176 against downward motion therethrough of the top panel side flaps 80; but, on the return or upstroke of the plunger, the slot resistance is effective to grip and hold the carton in place while the plunger shoe moves upwardly. In the event some slippage were to occur, the overhanging lips 122 on the rearward pair of retaining jaws would posi- 153. A connecting lever 156 tively bar any further upward movement of the carton and prevent jamming between the lowermost carton and the next or upper carton to descend.

Upon retraction of the plunger shoe from the partially formed carton located at the bottom end of the die, and supported by the retaining jaws, the final folding operation is ready to be undertaken. At this juncture, the carton is in the condition shown most clearly in Figure 10, and the side lock panels 81 (each including a side panel 82, a roll-over panel 86 and a roll-over panel retaining flap 88) are in vertical attitude. In order to place the carton in completed form, as shown in Figures 3 and 11, wherein the front and rear panel retaining flaps 72 and 76 are covered or confined securely, the panels 86 are each rolled over or curled inwardly to a vertical attitude about the scored line 84 as a hinge, and the retaining flap 88 recurved into a horizontal locking position. The machine of my invention provides mechanism to effect this result.

Mounted securely on each of the pair of brackets 43 on the vertically reciprocable arms 33 is a rod 201 extending horizontally and longitudinally and projecting through an elongated central slot 202 in a crank arm 203, the width of the slot being slightly greater than the rod diameter to permit translation of the rod in the slot. The crank arm and rod are held in 90 degree relation by a pair of washers 204 suitably mounted on the rod. The crank arm is pivotally mounted on an axle 206 supported for rotation in a bearing 207 on the machine. frame. Coaxial with the axle 206 and secured thereto is a first or upper sprocket wheel 208 in engagement with an endless sprocket chain 209 which is also reaved about a second or lower sprocket wheel mounted on the end of a finger shaft 212 rotatably disposed in suitable supports 213, see Figure 4, on the corresponding die side wall. Secured to each finger shaft 212 is a plurality of panel locking fingers 216, each of the fingers having a root portion 217 projecting outwardly from the finger shaft in a substantially radial direction, and a carton engaging portion 218 substantially normal to the root portion 217. The fingers are swingable, in response to rotation of the finger shaft between the lowermost position shown in Figure 4 and the uppermost retracted position shown in Figure 14, a plurality of recesses 221 being formed in the adjacent die side wall to receive the corresponding fingers when the fingers are in retracted location.

Owing to the various gears and linkages heretofore described, the fingers 216 rotate and assume predetermined, angular attitudes in dependence upon and in cooperation with predetermined plunger motion and plunger positions.

At the start of the first carton forming cycle, with the plunger in uppermost position, as shown most clearly in Figures 1 and 4, the fingers 216 are in a vertically down- Ward attitude. As the plunger is depressed, the horizontal rod 201 on the plunger arm bracket bears downwardly against the lower side of the crank arm slot 202, forcing the crank arm 203 to rotate outwardly and downwardly and to the position, for example, shown in outline in Figure 4 and designated by the numeral 226. As appears most clearly in Figure l, a vertical relief slot 227 is formed in the frame panel 22 to permit downward swinging of the crank arm. Corresponding to the crank arm position 226 is the finger location appearing in Figure 7, finger motion being in the upward direction indicated by the arrow 228. The next exemplified crank arm location is the position indicated by the numeral 231 in Figure 4, the corresponding finger attitude being shown I lowermost position at the same time, as appears in Figure 14.

At this juncture, the plunger returning springs 41 are permitted to retract the plunger upwardly, the partly formed carton being concurrently stripped from the plunger and remaining in position at the bottom of the die, supported by the carton retaining jaws, the carton at this time being in the shape or form shown in Figure 10. As the plunger moves upwardly, the crank arms and rollover fingers are correspondingly actuated, the fingers rotating inwardly from their recesses and into the die throat shortly after the plunger shoe has moved upwardly past the top of the recesses.

As will be apparent from Figure 15, each of the inwardly swinging fingers 216 comes into abutment with the top edge of the adjacent retaining flap 88. As the fingers continue to rotate inwardly they cause folding of the roll-over panel 86, about the scored line 84 as a hinge, to take place, bending proceeding as indicated by the outline positions designated 230 and 229, respectively, in Figure 15. At substantially the same time the plunger reaches its uppermost location, the fingers reach their lowermost position, indicated by the numeral 231 in Figure 15. Between the positions 229 and 231, the descending fingers force or sweep the edge of the lock panel retaining flap 88 against the bottom panel 66 of the carton, causing the fiap 88 to bend inwardly about the scored line 89 as a hinge and to assume the substantially horizontal position indicated in Figure 15 at the lowermost location 231 of the folding fingers. At this juncture the carton is in the fully formed condition shown in Figures 3 and 11. The carton forming and ejecting cycle is concluded as the plunger is again depressed, to start the folding cycle for the following carton, and the plunger is moved downwardly to approximately the plunger location shown in Figure 9, the plunger shoe with the next carton folded about it having, at this juncture, cammed the retaining jaws outwardly and having engaged not only the upper edge of the top panel fiap 79 but also the actuating finger 151 on the carton knock-out mechanism, and thus dislodging the completely formed carton. It can therefore be seen that not only the downstroke of the plunger is effective to fold a portion of the carton components but the plunger upstroke is also operative, the pressure on downstroke being utilized to effect folding of the heavier panels while the restoring forces of the return springs are used to cause folding of the roll-over panels and lock panels. By balancing the forces required an el'ficient machine is realized, a machine which at no time needs large force to effect folding.

What is claimed is:

l. A carton forming machine comprising a frame, a die mounted on said frame, said die including a plurality of walls encompassing a central vertical aperture, said Walls being surmounted by curved shoulders adapted to fold elements of acarton blank in predetermined order, a plunger movable through said die aperture in engagement with the carton blank and past said shoulders whereby elements of the carton blank are folded into predetermined carton form, means on said die for holding and for releasing the carton in dependence upon the location of said plunger, means mounted on one of said die walls for positively ejecting one side of the carton, and means on the opposite of said die walls for bowing inwardly an element of the carton whereby said plunger is enabled positively to eject the other side of the carton, said plunger and said ejecting means being concurrently operative.

2. A machine for converting into carton form an elongated carton blank including a bottom panel, a pair of side panels foldably connected to said bottom panel, a pair of retaining flaps on the ends of said side panels, a pair of end panels foldably connected to said bottom panel, a pair of roll-over flaps scoredly connected to said end panels, and a pair of locking flaps scoredly connected to said roll-over flaps, said machine comprising: a die, said die having a central aperture; a plunger movable downwardly and upwardly through said aperture, said die being effective to engage and fold said panels, said re taining flaps and said end panels into carton form around said plunger as said plunger moves downwardly to a location adjacent the bottom of said die; a pair of rockable jaw members mounted on each side of said die and spring-urged into projected position in said aperture, each of said jaw members including an upper lip adapted to overhang the upper edge of the adjacent of said side panels in said projected position of said jaw member, and a lower lip adapted to underlie the lower edge of the adjacent of said side panels in said projected position of said jaw member and to withdraw from said side panel as said jaw member is moved against spring urgency into retracted position, each of said jaws further including a cam surface engageable with said plunger as said plunger moves downwardly through said aperture to a predetermined location whereby said jaw member is urged into retracted position; a carton ejecting mechanism mounted on the side of said die, said mechanism comprising a first finger spaced vertically above a second finger and interconnected therewith, said first finger being spring urged into the path of said plunger and movable downwardly by said plunger, said second finger being located above said carton as said carton is supported by said jaw member, said second finger being urgeable by said first finger into abutment with the upper edge of the adjacent of said side panels concurrently with the retraction of said jaw member; and a pair of roll-over fingers rotatably mounted on each end of said die for folding said roll-over flaps and said locking flaps into said carton as said plunger is withdrawn from said die.

3. A machine for folding carton blanks comprising: a die having a vertical aperture; a plunger reciprocably movable between a first position above said die and a second position adjacent the bottom of said aperture; jaw means mounted on each side of said die and movable between a projected and a retracted location for supporting the carton in said projected location of said jaw means, said jaw means including a camming surface engageable with said plunger as said plunger moves from said first position toward said second position to urge said jaw means into said retracted location; carton ejecting means mounted on each side of said die engageable with and directly actuable by said plunger in moving from said first toward said second position for positively engaging and ejecting the carton in a vertically downward direction.

4. A machine for folding carton blanks of the rollover panel type comprising: a die with a central aperture; a plunger reciprocably movable between a first position above said aperture and a second position adjacent the bottom thereof; jaw mechanism mounted on opposite sides of said aperture and movable between a projected carton supporting location and a retracted carton releasing location, said jaw mechanism being directly engageable with said plunger as said plunger with a first carton thereon moves from said first position toward said second 10 position and being urged thereby from said projected toward said retracted location; finger mechanism mounted on the opposite ends of said aperture and swingable be tween a retracted location and a projected location in folding engagement with the adjacent first carton roll-over panel in dependence upon the vertical position of said plunger; and carton ejecting mechanism swingably mounted on opposite sides of said aperture including a first member directly engageable with said plunger as said plunger with a second carton thereon moves from said first position toward said second position and a second member urged downwardly by said first member into carton ejecting abutment with the first carton concurrently with the movement of said jaw mechanism from said projected to said retracted location.

5. A carton forming machine comprising a die having a central vertical aperture, a'plunger having a downward movement through said aperture between a first position above the top of said die and a second position adjacent the bottom of said die, a spring, means connecting said plunger to said spring for energizing said spring by reason of said downward movement, said plunger including a shoe engageable with a carton blank, said die including a plurality of pairs shoulders co-operatively disposed adjacent the top of said die to fold predetermined pairs of carton blank panels about said plunger shoe as said shoe is moved from said first position toward said second position, a plurality of carton panel locking fingers rotatably mounted adjacent the bottom of said die swingable between a projected position in said die aperture and a retracted position in recesses in said die, means driven directly by said plunger for rotating said fingers into said retracted position as said plunger moves downwardly toward said second plunger position, means for stripping said carton from said plunger as said plunger moves upwardly away from said second position, means operated by said spring for rotating said fingers into projected and carton panel locking position in response to the upward movement of said plunger away from said second plunger position, and means for ejecting said carton from said die as said plunger moves downwardly between said first position toward said second position.

6. A carton forming machine comprising a frame, a die on said frame, a plunger vertically movable through said die, a crank arm rotatably mounted on said frame, said crank arm having a slot therein, a pin on said plunger and extending into said slot whereby the vertical location of said plunger determines the angular position of said crank arm, a shaft rotatably mounted on said frame, a plurality of carton panel bending fingers on said shaft swingable by rotation of said shaft into panel folding engagement with said carton, and means for rotatably connecting said crank arm with said shaft.

References Cited in the file of this patent UNITED STATES PATENTS 1,430,232 Horton Sept. 26, 1922 2,614,466 Palmer Oct. 21, 1952 2,727,444 Wethe Dec. 20, 1955

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