US3149544A

US3149544A - Device for folding box blanks

Info

Publication number: US3149544A
Application number: US173494A
Authority: US
Inventors: Charles A Govatsos
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-02-15
Filing date: 1962-02-15
Publication date: 1964-09-22
Anticipated expiration: 1981-09-22

Description

p 22, 1964 c. A. GOVATSQS 3,149,544

. DEVICE FOR FOLDING BOX BLANKS Filed Feb. 15, 1962 5 Sheets-Sheet 1 Sept. 22, 1964 c. A. GOVATSOS DEVICE FOR FOLDING BOX BLANKS 5 Sheets-Sheet 2 Filed Feb. 15, 1962 P 22, 1964 c. A. GOVATSOS 3, ,5 4.

DEVICE FOR FOLDING BOX BLANKS Filed Feb. 15, 1962 3 Sheets-Sheet I5 I z e 4 66 [W w lweiii'or 6 8 CiaarZe'sflaovallsos,

United States Patent DEVICE FOR FOLDING BOX BLANKS Charles A. Govatsos, 33 Westgate Road, Wellesiey, Mass.

Filed Feb. 15, 1%2, Ser. No. 173,494 7 Claims. (Ci. 93-51) This invention relates in general to devices for folding box blanks and more particularly concerns a new and improved die and plunger fabricated principally from a relatively thin ply of laterally resilient plastic material and adapted to fold a lock type box blank in a single operation by means of the plunger forcing the blank through the die.

Typically, box folding machines have been mechanically complicated affairs employing a relatively large number of moving parts arranged to function in timed cooperation with one another. If the box that is to be set up is of the lock type in which slits and ears at each corner must be interlocked, the machine becomes even more complicated because of the need to open the slits and then insert the ears at the proper moment.

Recently, the machinery needed to fold boxes of the above type has been simplified by the use of a die which has been formed with contoured grooves and ribs adapted to fold a box blank that is passed through by means of a reciprocating plunger.

While the die and plunger type of box folding machine is a good deal simpler than those machines previously available, they are not entirely effective in bringing the ears into positive locking engagement with the slits. Furthermore, since any die and plunger set can accommodate but a single size blank, it is necessary that a die and plunger be available for each box size which must be set up. This represents a rather large capital outlay since the die and plunger are normally made from steel and are quite expensive to produce because of the tooling involved in the making of the die molds.

Accordingly, it is an object of the present invention to provide an improved die and plunger for use in setting up box blanks.

Another object of this invention is to provide a lowcost, easily fabricated die and plunger for use in box folding operations.

Still another object of this invention is to provide a device for setting up lock type box blanks so as to produce a positive locking engagement between the ears and slits.

Yet another object of this invention is to provide a onepiece box-forming die of laterally resilient material in which selected portions are disposed for yieldingly engaging portions of a box blank.

A further object of this invention is to provide novel means for preventing the formation of cracks and splits at joints of sheet material subjected to high stresses.

More particularly, this invention features a box-forming die and plunger fabricated from a relative thin ply of hard but laterally resilient plastic material and adapted to fold and lock in a single operation a lock type box blank. As another feature of this invention, Wing elements are provided at opposite ends of the plunger for engaging the ears after they have been passed through their respective slits and deflecting them inwardly so as to lock each ear in position.

A further feature of this invention relates to the use of resilient depending walls formed along the die opening and adapted to fold the hinged side panels of the blank somewhat beyond their normal folded position in order to compensate for the tendency of the folded side panels to bow outwardly, particularly in their center portions. But these and other features of the invention, along 3,149,544 Patented Sept. 22, 1964 with further objects and advantages thereof will become more readily apparent from the following detailed description taken in connection with the accompanying drawings in which:

PEG. 1 is a view in perspective of a box of the type that may be folded by operation of the die and plunger of this invention,

FIG. 2 is a top plan view of the plunger made according to this invention,

FIG. 3 is a top plan view of a die made according to the invention,

FIG. 4 is a cross-sectional View taken along the line A of FIG. 3,

FIG. 5 is a fragmentary top plan view showing the die, the plunger and a box blank just starting to be passed through the die opening,

FIG. 6 is a cross-sectional view taken along the line 66 of HG. 5,

FIG. 7 is a view similar to FIG. 5 but showing a further stage in the folding operation,

FIG. 8 is a crosssectional view taken along the line 8i-i of FIG. 7,

FIG. 9 is a cross-sectional view taken along the line 99 of FIG. 7,

FIG. 10 is a sectional view in end elevation showing a still further stage in the folding operation,

FIG. 11 is a top plan view showing a plunger somewhat modified in construction from that of FIG. 2,

H6. 12 is a cross-sectional view taken along the line 12-42 of FIG. 11, and,

FIG. 13 is an end elevation of the plunger of FIG. 11.

Referring now to FIG. 1 of the drawings, the reference character 10 generally indicates a fully set up paper board box having a rectangular center panel 12, side panels 14 hinged along opposite sides of the center panel and end panels 16 hinged along opposite ends of the center panel. A tuck flap or tab 18 with an outwardy projecting locking car 20 thereon is integral with each end of each side panel 14 and each end panel 16 is provided with angled slits 22 for receiving the locking ears 20.

Referring now more particularly to FIGS. 2 and 3, the improved apparatus for setting up the box blanks includes a plunger 24 (FIG. 2) and a die 25 (FIG. 3). The plunger is generally rectangular in plan View and preferably is molded from a hard, tough, relatively stiff and slightly resilient plastic material such as butadiene or any other moldable material that presents a relatively smooth hard surface, possesses a rather high degree of lateral stability in sheet or molded form and yet displays good flexing characteristics.

The plunger shown has a flat upper portion 26 with a slightly flared depending skirt or flange 23. The dimensions of the plunger correspond to those of the panel 12 so that the lower edges of the flange 28 will generally follow the fold lines of the box blank. Mounted at each end of the plunger is an upright wing 30 which is separately formed of metal and attached by bolts, rivets or the like to a flattened should-er portion 32. The side edges of the wing 30 are somewhat inclined and are curved outwards for reasons that will presently appear. It will be noted that the curved portions of the wing 30 extend beyond the shoulder 32 to define a reentrant opening 34 with the flange of the plunger.

In practice, the plunger 24 is attached to a reciprocating element such as a piston for apneumatic cylinder and is provided with several openings 36 to accommodate connecting bolts.

Referring now to FIG. 3, the die 25 is formed from the same plastic material as the plunger 24 and is rectangular in plan view having a rather Wide fiat flange 38 with marginal openings 40 for securing the die to a stand or base in register with the plunger 24. The die is formed elegant with a generally rectangular central opening 42 downwardly therethrough of a size corresponding to that of the panel 12 and permitting passage of this panel therethrough. The die includes integral raised end shoulders 44 and recessed side shoulders 46 which define the opening 42 and present curved surfaces to fold first the end and then the side panels of the box blank upwardly as the blank is forced downwardly therethrough as shown in FIGS. 5-10. Depending end and side walls 48 and 59 extend downwardly from the

shoulders

44 and 46 respectively to define an abbreviated chute down which the box is passed.

The side shoulders 46 and their depending walls 5% are curved inwardly as best shown in FIGS. 9 and 10, to restrict the Width of the opening 4-2 to a certain extent. It will be noted in FIG. 3 that the curved side wall sections 50 are not directly connected to the end walls 48 but rather are separated from them by slits 54 which follow the corners of the opening 42, angle inwardly across the curved shoulder 46 and terminate in small circular open ings 56. This arrangement together with the natural resiliency of the die material permits the wall sections 50 to flex to a certain extent and to spread outwardly under the force of the plunger as it passes through the opening. The curved side shoulders 46 and side walls 5% serve to erect the side panels 14 of the box blank and, by reason of their curved and flexible construction, fold the side panels 14 in excess of 90 so as to compensate for the tendency of the side panels to return to their original flat condition. The end result is that when the box is fully set up, its side panels are perpendicularly erect and longitudinally straight.

In order to prevent the formation of cracks which might otherwise develop because of the stresses generated by constant flexing of the curved wall and shoulder sections, the slots 54 have been terminated with the circular openings 56. These openings, as best shown in FIG. 4, are charnfered so s to present a thin inner edge 53. By forming the thin inner edge about the opening 56, the tendency of the material to crack or split is greatly reduced. This is due to the fact that thin material undergoes much lower stresses when flexed than does thick material. By way of explanation, it will be appreciated that the stress present on the surface of a sheet that has been bent under pressure is dependent upon its distance from the center of flex. Assuming, for example, that material one inch thick is bent under pressure, the outer curved surface will be under a tension stress whereas the inner curved surface will be compressed. The amount of tension in the region of the outer curved surface would be much less than that for a similar material two inches thick since the distance to the center of the fiex is less. Accordingly, by chamfering the edges of the circular opening 56 the stresses in the area where a crack would normally originate are substantially reduced.

Referring again to FIG. 3, it will be noted that the end shoulders 44 are each provided with a rather wide vertical rib 60 with narrower ribs 62 formed parallel thereto and adjacent to the corners of the opening 42.

In order to clarify the functioning of the die and plunger, reference is made to FIGS. 5-10 which show a box blank in the various stages of assembly. Referring now to FIG. 5, a blank is shown in the first stage of the folding operation with the plunger 24 having pressed the blank down over the end of shoulders 44. At this point, the side panels 14 are still in a horizontal position whereas the end panel 16 has been raised to a vertical position by means of the shoulder 44.

As the plunger moves the blank further down through the opening 42 the side shoulders 46 meet with the side panels 14 to urge them into an upright position. Simultaneously, the wings 30 cooperate with the ribs 62 to open up the slits 22 by the rib pushing inwardly against the end panel on one side of the slit while the wing pushes outwardly against the end panel on the other side of the 4 slit. As the slit opens the locking ear 2! is passed through and is received in the reentrant opening 34 of the plunger.

The plunger continues downward with the curved walls 54} being flexed apart while bending the side panels 14 in the manner described above. At the bottom of the stroke the top edges of the box clear the bottom edges of the die and the plunger is retracted. The box is stripped from the plunger as it retracts by the upper edges of the end panels butting against the lower edges of the end walls 48. Also, as the plunger retracts the curved and inclined edges of the Wings 30, which had been between the looking ears 20 and the end panel 16, move up and out of this position and thereby wipe the locking ears to insure a positive locking engagement with the edges of the slits 22.

In FIGS. 1ll3 a modification of the plunger is illustrated. In this embodiment a plunger 64 is molded entirely in one piece with wings 66 formed as an integral part of the plunger body rather than as separate elements as in the principal embodiment. The configuration is similar to that of the plunger in FIG. 2 with the exception that a skirted flange 65: has been made somewhat deeper than that of the plunger 24 and a wing 66, of a design similar to that of the wing 3%, depends from each end of the flat top portion of the plunger.

While the invention has been described with particular reference to the illustrated embodiment, it will be understood that numerous modifications will appear to those skilled in the art without departing from the invention. For example, a wide variety of materials may be employed to form the die and plunger parts. Laminated fiber glass, for example, would possess the proper strength, rigidity and flexibility characteristics required for the parts. Other materials may also be used to advantage.

Having thus described my invention, what I claim and desire to obtain by Letters Patent of the United States is:

1. Apparatus for setting up into box form a flat blank having a rectangular bottom panel together with hinged side and end panels, tuck flaps with outwardly projecting locking ears integral with the ends of the side panels and slits in each end panel for receiving the adjacent ears in locking engagement, comprising a one piece die having a generally rectangular opening formed therein of a size generally corresponding to the dimensions of said bottom panel, said die being formed from a relatively thin ply of a laterally resilient plastic material having a smooth hard outer surface and being of substantially constant thickness, downwardly curved side and end shoulders formed along said die opening for folding said side and end panels upwardly when said blank is forced downwardly through said opening, inwardly curved flexible side walls depending from said side shoulders and normally restricting the size of said opening for yieldingly engaging said side panels, said die being formed with recesses between said side and end shoulders to permit said side walls to flex under pressure, end walls depending from said end shoulders, ribs formed on said end shoulders and extending down said end walls, a plunger of generally the same dimensions as said bottom panel and wing members mounted on opposite ends of said plunger, said wing members in cooperation with said ribs being adapted to open said slits by applying opposing pressures to diagonally opposite sides of each of said slits, said shoulders and said side walls being adapted to fold said ears into said slits as said plunger advances said blank through said opening, said wings being further adapted to wipe said ears inwardly upon retraction of said plunger.

2. Apparatus for setting up into box form a fiat blank having arectangular bottom panel together with hinged side and end panels, tuck flaps with outwardly projecting locking ears integral with the ends of the side panels and slits in each end panel for receiving the'adjacent ears in locking engagement, comprising a thin-walled one piece die having a generally rectangular opening formed therein of a size generally corresponding to the dimensions of said bottom panel, said die being formed of a ply of laterally resilient plastic material of substantially constant thickness, downwardly curved side and end shoulders formed along said die opening for folding said side and end panels upwardly when said blank is forced downwardly through said opening, flexible side walls freely depending from said side shoulders and normally restricting the size of said opening for yieldingly engaging said side panels, end walls depending from said end shoulders, ribs formed on said end shoulders and extending down said end walls, a plunger adapted to force said blank through said opening and curved wing members mounted on opposite ends of said plunger, said wing members in cooperation with said ribs being adapted to open said slit by applying opposing pressures on opposite sides of each of said slits, said shoulders and said side walls being adapted to fold said ears into said slits as said plunger advances said blank through said opening, said wings being further adapted to wipe said ears inwardly when the formed blank is stripped from said plunger.

3. Apparatus for setting up into box form a flat blank having a rectangular bottom panel together with hinged side and end panels, tuck flaps with outwardly projecting locking ears integral with the ends of the side panels and slits in each end panel for receiving the adjacent ears in looking engagement, comprising a one piece die having an opening formed therein generally corresponding to the dimensions of said bottom panel, said die being formed of a ply of moldable laterally resilient plastic material of substantially constant thickness, shoulders formed about said die opening for folding said side and end panels at generally right angles to said bottom panel when said blank is forced flatwise through said opening and freely extending flexible side walls depending from said shoulders and curving inwardly to normally restrict the size of said opening for yieldingly engaging said side panels.

4. Apparatus for setting up into box form a fiat blank having a rectangular bottom panel together with hinged side and end panels, tuck flaps with outwardly projecting locking ears integral with the ends of the side panels and slits in each end panel for receiving the adjacent ears in locking engagement, comprising a die having an opening formed therein generally corresponding to the dimensions of said bottom panel, said die being formed of a laterally resilient plastic material, shoulders formed about said die opening for folding said side and end panels at generally right angles to said bottom panel when said blank is forced flatwise through said opening and thin-walled flexible side walls depending from said shoulders for yieldingly engaging said side panels.

5. Apparatus for setting up into box form a flat blank having a rectangular bottom panel together with hinged side and end panels, tuck flaps with outwardly projecting locking ears integral with the ends of the side panels and slits in each end panel for receiving the adjacent ears in locking engagement, comprising a one piece thin-walled die having an opening formed therein generally corresponding to the dimensions of said bottom panel, said die being formed of a material of substantially constant thickness, shoulders formed about said die opening for folding said side and end panels upwardly when said blank is forced downwardly through said opening in a fiatwise position, and flexibly connected sidewalls integral with said die and extending freely from at least an opposite pair of said shoulders, said side walls presenting curved surfaces normally restricting the size of said die opening for yieldingly engaging said side panels.

6. Apparatus for setting up into box form a flat blank having a rectangular bottom panel together with hinged side and end panels, tuck flaps with outwardly projecting locking ears integral with the ends of the side panels and slits in each end panel for receiving the adjacent ears in locking engagement, comprising a thin-walled one piece die having an opening formed therein of a size generally corresponding to the dimensions of said bottom panel said die being formed of a laterally resilient and substantially non-compressible plastic material of generally constant thickness and shoulders formed about said die opening for folding said side and end panels upwardly when said blank is forced downwardly through said opening in a fiatwise condition.

7. Apparatus for setting up into box form a flat blank having a rectangular bottom panel together with hinged side and end panels, tuck flaps with outwardly projecting locking ears integral with the ends of the side panels and slits in each end panel for receiving the adjacent ears in locking engagement, comprising a die having an opening formed therein generally corresponding to the dimensions of said bottom panel, said die being formed of a self supporting laterally resilient plastic material, shoulders formed about said die opening for folding said side and end panels at generally right angles to said bottom panel when said blank is forced flatwise through said opening and thin-Walled flexible side walls depending from said shoulders for yieldingly engaging said side panels, said die being formed with arcuate reentrant recesses at the juncture of said side Walls and said shoulders, the edges of said recesses being chamfered.

References Cited in the file of this patent UNITED STATES PATENTS 2,512,161 Ledel June 20, 1950 2,516,624 Guyer July 25, 1950 2,580,189 Pagendarm Dec. 25, 1951 2,626,545 Samsing July 27, 1953 2,852,897 Woodworth Sept. 23, 1958 2,899,849 Laughter et al Aug. 18, 1959 2,995,991 Trelford Aug. 15, 1961

Claims

3. APPARATUS FOR SETTING UP INTO BOX FORM A FLAT BLANK HAVING A RECTANGULAR BOTTOM PANEL TOGETHER WITH HINGED SIDE AND END PANELS, TUCK FLAPS WITH OUTWARDLY PROJECTING LOCKING EARS INTEGRAL WITH THE ENDS OF THE SIDE PANELS AND SLITS IN EACH END PANEL FOR RECEIVING THE ADJACENT EARS IN LOCKING ENGAGEMENT, COMPRISING A ONE PIECE DIE HAVING AN OPENING FORMED THEREIN GENERALLY CORRESPONDING TO THE DIMENSIONS OF SAID BOTTOM PANEL, SAID DIE BEING FORMED OF A PLY OF MOLDABLE LATERALLY RESILIENT PLASTIC MATERIAL OF SUBSTANTIALLY CONSTANT THICKNESS, SHOULDERS FORMED ABOUT SAID DIE OPENING FOR FOLDING SAID SIDE AND END PANELS AT GENERALLY RIGHT ANGLES TO SAID BOTTOM PANEL WHEN SAID BLANK IS FORCED FLATWISE THROUGH SAID OPENING AND FREELY EXTENDING FLEXIBLE SIDE WALLS DEPENDING FROM SAID SHOULDERS AND CURVING INWARDLY TO NORMALLY RESTRICT THE SIZE OF SAID OPENING FOR YIELDINGLY ENGAGING SAID SIDE PANELS.