US2830505A

US2830505A - Method of forming cartons

Info

Publication number: US2830505A
Application number: US341998A
Authority: US
Inventors: Guyer Reynolds
Original assignee: Waldorf Paper Products Co
Current assignee: Waldorf Paper Products Co
Priority date: 1953-03-12
Filing date: 1953-03-12
Publication date: 1958-04-15
Anticipated expiration: 1975-04-15

Description

A ril 15, 195

GUYER METHOD OF FORMING CARTONS Filed March 12, 1953 I INVENTOR 20v Reyna/d5 Gaye/5' W1 mam 6 A RNEY United States Patent O METHOD OF FORMING CARTONS Reynolds Guyer, St. Paul, Minn, assignor to Waldorf Paper Products Company, St. Paul, Minn, a corpora tion of Minnesota Application March 12, 1953, Serial No. 341,998

2 Claims. (Cl. 9336.8)

This invention relates to an improvement in method of forming cartons and deals particularly with the manner of folding cartons of a particular type.

Cartons have previously been produced having what is known as a tear corner structure. In other words, the slits which separate the individual flaps of the carton do not extend completely to the fold line extending around the cartons ends. As a result when these carton flaps are folded down into carton closing position, the carton stock tears for a short distance forming a web which acts as a seal at the corner of the carton. The structure is particularly effective where a cut score is cut partially through the outer surface of the carton extending from the end of the slit to the line of fold so that only the inner surface or liner stock is torn away.

While cartons of this type have been found effective for their desired purpose, diificulty has been found in folding the flaps into sealing position and properly tearing the stock. The depth of the cut score varies somewhat in different cartons and as a result the carton corners do not always tear properly. In many instances the carton stock tears directly through the corner of the carton, thereby destroying the effectiveness of the seal and preventing the formation of the small web which acts to seal the carton corners. The present invention resides in the particular manner of folding such cartons which has resulted in more elfective sealing than other arrangements.

An object of the present invention resides in the provision of folding the flaps of a carton of the type described which includes the steps of folding two opposed fiaps inwardly simultaneously with the outward folding of the remaining two flaps. When the flaps are folded in this specific manner, the carton stock tears away more effectively than would otherwise be the case and the proper formation of the web at each corner of the carton is insured.

A feature of the present invention resides in providing a webbed corner carton having webs torn away from each corner of the carton and in producing these webs by folding two opposed flaps downwardly into a common plane while at the same time moving the remaining flaps outwardly so as to pull the paper at substantially right angles. This action tends to pull the inner portion of the paper stock away from the remainder thereof at the corners, this right angle pulling strain being substantially more effective than doubling the stock and pulling almost in the plane of the remaining upstanding flaps.

These and other objects and novel features of the invention will be more clearly and fully set forth in the following specification and claims.

In the drawings forming a part of the specification:

Figure l is a diagrammatic view of a portion of the blank from which the carton is constructed.

Figure 2 is a perspective view of the carton in partially folded condition.

Patented Apr. 15, 1958 ice Figure 3 is a perspective view of the carton in a different stage of the closing operation.

Figure 4 is a perspective view of the sealed carton, a portion of the layers of the closing flaps being cut away to show the interior construction.

Figure 5 is a perspective view of a corner of the carton during the folding action.

Figure 6 is a sectional view, the position of the section being indicated by the line 66 of Figure 1.

The carton is not shown in its entirety, as both ends of the carton may be similar or the bottom end of the carton may be or" somewhat different style. In the closing operation, one end of each carton may be sealed over a mandrel and accordingly a better seal may be obtained than is usually possible at the last closed end of the carton.

The carton is shown as including front and rear panels 1t} and ill. and

side wall panels

12 and 13. These panels are foldably connected together by

parallel fold lines

1d, 15, and 16. A glue flap 17 is foldably connected to one end panel of the series such as the panel 10 by a fold line 19.

Closing

flaps

20, 21 are hingedly connected to two of the panels 12 and along a common fold line 22. These flaps 2d and 21 are arranged to fold into a common plane from opposite sides of the carton. A third closing flap 23 is hingedly connected to the panel 10 along the fold line 22. A fourth closing flap 24 is hingedly connected along the fold line 22 to the wall panel 11. A short extension 25 is foldably connected to the glue flap 1']. When the glue flap 17 is secured to the side wall 13, the fiap extension 25 is foldably connected to the surface of the closing flap 21.

The various closing flaps are separated by slits'which do not extend entirely to the fold line 22. In other words, the slit 26 which is between the

closing flaps

20 and 23 terminates short of the fold line 22; A cut'score extends from the end of the slit 26 to the fold line 22. As shown in Figure .6 of the drawings, the slit'26 which separates the flaps 22 and 23 terminates at a distance from the fold line 22 and the cut score 27 which communicates with the slit 26 cuts only partially through the carton stock and connects the slit 26 to the fold line 22.

A similar arrangement is provided between each pair of adjacent flaps. A slit 2% is provided between the flaps 2t) and 24 and this slit 29 terminates short of the fold line 22 and is connected thereto by a cut score similar to the cut score 27. A. slit 3% is provided between the

closing flaps

21 and 24 and this slit 30 also terminates short of the fold line and a cut score forms a continuation thereof.

The glue flap extension 25 is also separated from the adjoining closing flap 23 by a slit 31 which terminates short of the fold line 22. and which is connected thereto by a cut score. Thus all of the slits between all of the flaps terminate short of the fold line.

I have found that with this arrangement some diificulty is experienced in folding the various flaps without tearing the paperboard along the line of the cut score or in alignment with the slits. When all of the four flaps are in the same plane as the panel to which they are hinged and when t e two shorter panels are folded down into a common plane, the paper forms a fold at each end of the shorter flaps and tends to tear off along a line of the cut score. This destroys the usefulness of the construction as we desire to provide a web or gusset of paper at each corner of the carton. We have also found that if the shorter flaps are held in vertical position and the wider flaps are folded upwardly into a fiat condition, there is also a tendency to tear the paper along the cut score. However, we have found that if the fold ing actions take place simultaneously and the shorter or inner flaps are folded inwardly simultaneously with the outward folding of the outer flaps, the carton stock will tear and produce a generally triangular gusset.

Accordingly it is the object of the present invention to fold the shorter or narrower inner flaps downwardly and to simultaneously fold the wider or outer flaps outwardly. This tends to tear the inner liner of the carton board away from the outer portion thereof to form a generally triangular gusset at the carton corners, the inward folding of the shorter flap acting to create a pulling force against the inner liner which is at all times substantially at right angles to the wider flaps or substantially in the plane of the shorter flaps. This tearing action continues until the portion torn away is of sufficient length to reach the edge of the shorter flap when these flaps are in coplanar relation. In other words, the tearing action takes place through an angle of approximately forty-five degrees, the end of the torn portion being connected to the wider flaps along diagonal lines about forty-five degrees in angle from the fold line 22.

When the

innermost flaps

20 and 21 are folded into a common plane and when the

wider flaps

23 and 24 are also folded outwardly into the same plane, a web of thin paper tape may be secured across the entire top of the carton, the marginal edges of the tape being anchored to the

wider flaps

23 and 24. This particular construction is not a part of the present invention. However, the particular method of folding the flaps to accomplish the desired tearing action in the corners of the carton is an important part of the present invention.

After the carton has been folded into the position shown inFigure 3, the web may be attached if it is so desired. Subsequently the shorter flap 23 is folded to overlie the coplanar inner flaps 20 and '21 and thereafter the wider closing flap 24 is folded to extend entirely over the remaining flaps. If the inner web is omitted, both the

flaps

23 and 24 may be of equal width as is usual in such cartons.

In accordance with the patent statutes, the principles of construction and operation of the method of forming cartons has been described, and while it has been endeavored to set forth the best embodiment thereof, it

is desired to have it understood that these are only illustrative thereof and that obvious changes may be made within the scope of the following claims without departing from the spirit of the present invention.

I claim:

1. A method of producing a tight sealed paper board carton from a rectangular tubular carton blank having closing flaps foldably connected to the carton walls, the flaps being separated by slits which terminate outwardly of the fold lines connecting the flaps to the carton walls, the method consisting in folding two opposed closing flaps outwardly and simultaneously folding the remaining opposed flaps inwardly, the inward movement of the remaining flaps maintaining the direction of pull at substantially right angles to the line of tear, the combined movement of the flaps tearing a portion of the thickness of the paperboard from the inner surfaces of the flaps folded outwardly, forming gussets at the carton corners.

2. A method of producing a tight sealed paper board carton from a rectangular tubular carton blank having closing flaps foldably connected to the carton walls, the flaps being separated by slits which terminate outwardly of the fold lines connecting the flaps to the carton walls, and having cut scores extending through the outer surface of the flap portions between the ends of the slits and the adjacent carton corners, the method consisting in folding two opposed flaps outwardly and simultaneously folding the remaining opposed flaps inwardly, the inward movement of the remaining flaps maintaining the direction of pull at substantially right angles to the line of tear, the combined movement of the flaps creating a pulling action against the uncut portion of the paperboard inwardly of the cut scores and pulling a portion of the thickness of the paperboard forming the outwardly folded flaps away from the remainder of the flaps to produce a gusset fold at each corner of the carton.

References Cited in the file of this patent UNITED STATES PATENTS 2,485,235 Graf Oct. 19, 1949