US3902653A

US3902653A - Blank for a carton box having corner locking

Info

Publication number: US3902653A
Application number: US463410A
Authority: US
Inventors: Karl Rune Persson
Original assignee: Sprinter Pack AB
Current assignee: Sprinter Pack AB
Priority date: 1973-05-09
Filing date: 1974-04-23
Publication date: 1975-09-02
Anticipated expiration: 1992-09-02
Also published as: JPS58125112U; GB1458907A; DE2422418C2; DE2422418A1; JPS5014467A; SE372916B

Abstract

The panels meeting at the respective corner of a carton box are locked by means of a locking tongue of one panel being inserted into a locking slit in the other panel, said locking tongue having a hook-like projection at its upper edge which can be inserted into the slit merely by first flexibly bending the tongue so that the hook-like projection may engage the end of the slit.

Description

"United States Patent [191 Persson [4 1 Sept. 2, 1975 BLANK FOR A CARTON BOX HAVING CORNER LOCKING [75] Inventor: Karl Rune Persson, Halmstad,

Sweden [73] Assig'nee: Sprinter Pack AB, Halmstad,

Sweden [22] Filed: Apr. 23, 1974 [21] Appl. No.: 463,410

[30] Foreign Application Priority Data May 9, 1973 Sweden 065294 [52] US. Cl 229/35; 229/75 [51] Int. Cl. B65D 5/26 [58] Field of Search 229/31 R, 31 F8, 33, 35

[56] References Cited UNITED STATES PATENTS 2,718,998 9/1955 Bemiss 229/35 2,955,737 10/1960 Armeson 229/35 2,982,464 5/1961 Wingate 229/35 3,393,859 7/1968 Glummo... 229/35 3,608,811 9/1971 Frick 229/31 R Primary ExaminerDavis T. Moorhead Attorney, Agent, or FirmOstro1enk, Faber, Gerb & Soffen ABSTRACT The panels meeting at the respective corner of a carton box are locked by means of a locking tongue of one panel being inserted into a locking slit in the other panel, said locking tongue having a hook-like projection at its upper edge which can be inserted into the slit merely by first flexibly bending the tongue so that the hook-like projection may engage the end of the I slit.

3 Claims, 6 Drawing Figures PATENTED 2 SHEET 1 OF 2 FIG.1

BLANK FOR A CARTON BOX HAVING CORNER LOCKING The present invention relates to a blank for carton boxes having corner locking of the kind set forth in the preamble to the accompanying main claim.

A number of such corner locks are known. The object of the invention is to effect a new design of such a corner lock, where the locking tongue of the one side wall panel, upon erecting the blank, guidingly moves into a locking slit in the other side wall panel end flap and snaps to a secure locking position when the end edges associated with the respective corners of the side wall panels lie adjacent each other. This is made possible by a blank having the distinguishing features set forth in the accompanying claims.

A suitable embodiment of the blank, and the erected carton box having corner locking according to the invention will now be described, making reference to the attached drawings.

FIG. 1 shows a carton box blank having corner locking according to the invention,

FIG. 1a is an enlarged partial view of the blank,

FIG. 1b corresponds to FIG. la and shows'a somewhat modified embodiment,

FIG. 2 is an enlarged diagrammatic perspective view of a corner portion of the box, where the one side is erected and has its end flap folded inwards for receiving the locking tongue of the other side, the tongue being shown in an erected position, with the associated side wall in a lying position,

FIG. 3 shows the same position as FIG. 2 in a view from the side, the locking tongue and its side wall being shown with dotted lines in a number of positions during the introduction of the locking tongue into the locking slit,

and FIG. 4 is a diagrammatic perspective view seen towards the inside of a corner with the locking tongue in the locked position.

The blank in FIG. 1 has a bottom and

sidewalls

11,12, 13,14 hingeably attached thereto by means of hinged folding lines, and a lid 15. For the sake of simplicity, only the corner portion of the blank for

side walls

11,12 will be described, since remaining corner portions are identical with it. The lid may possibly be excluded, the blank then being intended to form a tray.

Side wall 11 may be folded up along a hinged folding line 16, and side wall 12 may be folded up along a hinged folding line 17.

Side wall 11* has an end flap 18 which can be folded in along a parted hinged folding line 19,1911, and side wall 12 has an end flap in the shape of a tongue 20 which can be folded in along a hinged folding line 21.

In the end flap 18 there is a locking slit consisting of a straight outer slit portion 22, parallel with the hinged folding line but somewhat displaced sideways. The outer end 23 of the slit portion is directed towards the outer hinged folding line 19a and extends up to it to bound a small our 25, and a slantingly directed slit portion 26 which extends in a direction towards side wall 12 in FIG. 1. The inner end of the straight slit 22 connects with the outer end portion 24 of the slanting slit portion. Between hinged folding line 19 and the slanting slit portion 26 a wedge-shaped portion 27 is thus obtained, the narrow end of which is terminated by the end edge obtained at the end portion 24 of slit 26.

The tongue 20 of side wall 12 has its hinged folding line 21 situated somewhat to one side of the end edge 28 of the side wall. Both the

side edges

29,30 of the tongue extend arcuately outwards and meet at the outer end of the tongue. At its inner edge, the inner side edge 29 connects with the slit 28a which, in the embodiment according to FIG. 1a, separates the end flap 18 from the wall 12 to make end edge 28. The slit 28a extends up to the hinged folding line 21, where the slit has a small end portion 31 directed towards hinged folding line 21. This end portion 31 is at a distance from hinged folding line 17 which is substantially the same as the distance between hinged folding line 16 and end portion 24 of the slanting slit portion which is slantingly directed towards hinged folding line 19.

Through the shaping of tongue 20 described above, it will have a freely projecting flexible corner flap 32 lying in the vicinity of end edge 28 of the side wall. The corresponding edge of tongue 20 forms a locking edge 32a (FIGS. 2, 3, 4) which is parallel with the hinged folding line 21, but is displaced sideways a distance which is approximately the same as double the carton thickness of the blank in question. The tongue is hereby given a neck 20a which has a corresponding short length.

In the embodiment according to FIG. lb, the end flap 18a is hingeably connected at its lower edge to side wall 12 along a hinged folding line 28b. To guide the necessary double folding of flap 18a there is a 45 fold line 34. A tighter corner in the tray is obtained by this process. In all other respects, both the blanks in FIG. 1a and 1b are the same.

In FIGS. 2, 3 and 4, only the erection of the blank according to FIG. 1a is shown, but erecting the blank according to FIG. 1b takes place in the same way.

As may be seen from FIG. La (and FIG. 111 also) the outer or upper edge 30 of the tongue 20 is connected via a shoulder 35 to the outer or upper end of the hinged folding line. The edge of the shoulder is terminated by an end portion 30a at the bottom of the wedge-shaped space or gap between the end edge 12a of the side wall l2 and the opposite portion of edge 30.

To obtain the locking as intended by the invention, the distance from corner point 36 (FIG. 1a) at the abutting ends of

hinge folding lines

16,17 to the outer or upper end 23 of slit portion 22 should be approximately the same as, suitably slightly less than, the distance from point 36 to the outer or upper end of folding line 21 and the end portion 30a of edge 30 respectively.

The distance from point 36 to the outer or upper end 26 of the slanting slit portion is further approximately the same as, suitably slightly less than, the distance from point 36 to the inner or under end of folding line 21 and the end portion 31 respectively. The intention in the selection of these distances will be seen below.

When erecting the blank in the machine, the parts of the blank will not normally assume the position shown in FIG. 2, there usually being, a mainly simultaneous erection of the side walls and folding in of the end flaps. The positionaccording to FIG. 2 is therefore only intended to facilitate understanding the invention.

When erecting

side walls

11 and 12, the end flap 18 is folded in before the tongue .20.

The side wall 1 1 is folded up by bending along folding line 16.

Side wall 12 is however folded up by a new method, namely by partly folding along folding line 17 and by partly simultaneous bending wall 12, as is shown by the different positions in FIG. 3, so that the tongue will lie at a minor distance from folding line 17 and the upper end 30b of the tongue will be moved in to a path of movement 37, the radius of which to folding line 17 is approximately equal to, suitably somewhat smaller than, the distance between the upper end 23 of slit 22 and folding line 17. By bending wall 12 in this way, the tongue 20 can pass in through

slit

22,26 so that the shoulders 35 of the tongue engage about the upper end 23 (FIGS. 3 and 4) of slit 22 in a hook-like manner. A

very secure lock is hereby obtained. This is secured by I the lower corner flap 32 of the tongue being also bent sideways when it passes through the slanting slit portion 26, to spring back again afterwards to the locking position shown in FIG. 4, where the tongue edge 32a abuts the wedge-shaped portion 27 of end flap 18. This lower locking prevents wall 12 from bending back again, which could cause shoulder 35 to release its aforementioned grip.

To facilitate bending of side wall 12 the grain of the carton material is longitudinal in the side wall.

The blank according to the invention gives smooth outside side walls, which is an advantage, amongst other things when decoration is to be applied to the side walls. There are furthermore no slits in the side walls which could reduce the tightness of the tray or box. Moreover, the corners will be stable because of the special arrangement of tongue 20 and end flap 18 according to FIG. 4.

What I claim is:

l. A blank for a carton box or tray having side walls extended at their ends with end flaps foldable along hinged folding lines provided at the respective corner of the box, a locking slit being provided at the hinged folding line of a first one of the end flaps, a second slit diagonally aligned with the locking slit and being joined to the locking slit at the lower end of the locking slit, the second end flap forming a tongue having a tapered free end, a widened central portion and a narrow neck portion in the region where it is joined to its side wall along said hinged folding line, characterized in that the inner end of the tongue is separated from its side wall by a third slit, that the opposite side of the locking tongue extends from the outer end of the hinged folding line of the tongue and forms a wedge-shaped space or gap with the edge of the adjacent side wall, that in the vicinity of its inner end said gap has a width which is preferably approximately double the thickness of the blank, that one side of the gap forms the edge of a shoulder-shaped portion, and that the distance from the corner point of the blank, lying at the merging ends of the hinged folding lines of the side walls, to the outer end of the locking slit is approximately the same as the distance from said corner point to the bottom of said wedge-shaped gap, so that the inner end of the tongue opposite the gap enters into and is bent by the second slit upon an insertion of the tongue into the locking slit and that the shoulder-like portion of the tongue is hooked into the slit to a locking position upon erecting the blank, with the inner end of the tongue being passed through the second slit and locked by the portion of the end of the first end flap between the first end flap folding line and the second slit.

2. Blank according to claim 5, characterized in that the grain direction of the carton material is longitudinal in the side wall, provided with a tongue, to facilitate bending of the side wall.

3. A blank for a carton box or tray having side walls extended at their ends with end flaps foldable along hinged folding lines at the respective corner of the box, a locking slit being provided at the hinged folding line of the one end flap, and the other end flap forming a locking tongue which is insertable into the locking slit and lockable in it, characterized in that one side of the locking tongue starts from the outer end of the hinged folding line of the tongue, and forms a wedge-shaped space or gap with adjacent side wall, that in the vicinity of its inner end the gap has a width which is preferably approximately double the thickness of the blank, that one side of the gap forms the edge of a shoulder-shaped portion, and that the distance from the corner point, lying at the ends of the hinged folding lines of the side walls, to the outer end of the slit is approximately the same as the distance from said corner point to the bottom of said wedge-shaped gap, so that the side wall of the tongue must be bent in order that the shoulder-like portion of the tongue can be hooked into the slit to a locking position on erecting the blank; said tongue being provided with a short neck, the inner end of which is hingeable along the hinged folding line of the tongue, and the length of which is preferably approximately the same as double the thickness of the blank, that the inner side edge of the neck merges into a locking edge parallel with the hinged folding line, said locking edge line connecting with the inner end of the adjacent side edge of the tongue so that the corner portion of the tongue between the locking edge and the inner side edge of the tongue forms a free flexible corner flap, that the locking slit in the other end flap lies between an outer and an inner portion of the hinged folding line for this end flap, and is composed of an outer straight slit portion and an inner slantingly directed slit portion, that the outer slit portion is parallel with the end flap hinged folding line, but is placed sideways relative to it, that the outer end of the straight slit portion connects with the outer portion of the hinged folding line of the end flap via a slit end portion, that the slanting slit portion is taken up in the end flap and forms an acute angle with the inner portion of the hinged folding line and has an end portion at its outer end which extends in towards the inner portion of the end flap hinged folding line, that the inner end of the straight slit portion connects with said end portion, and that the distance from the transition between the straight slit portion and the slanting slit portion to adjacent hinged folding line between the side wall and the box bottom is substantially the same as the distance between the inner end of the hinged folding line of the tongue and the hinged folding line between the associated side wall and the box bottom, so that on erecting the box and inthe tongue, to a locking position.

=l l l

Claims

1. A blank for a carton box or tray having side walls extended at their ends with end flaps foldable along hinged folding lines provided at the respective corner of the box, a locking slit being provided at the hinged folding line of a first one of the end flaps, a second slit diagonally aligned with the locking slit and being joined to the locking slit at the lower end of the locking slit, the second end flap forming a tongue having a tapered free end, a widened central portion and a narrow neck portion in the region where it is joined to its side wall along said hinged folding line, characterized in that the inner end of the tongue is separated from its side wall by a third slit, that the opposite side of the locking tongue extends from the outer end of the hinged folding line of the tongue and forms a wedgeshaped space or gap with the edge of the adjacent side wall, that in the vicinity of its inner end said gap has a width which is preferably approximately double the thickness of the blank, that one side of the gap forms the edge of a shoulder-shaped portion, and that the distance from the corner point of the blank, lying at the merging ends of the hinged folding lines of the side walls, to the outer end of the locking slit is approximately the same as the distance from said corner point to the bottom of said wedge-shaped gap, so that the inner end of the tongue opposite the gap enters into and is bent by the second slit upon an insertion of the tongue into the locking slit and that the shoulder-like portion of the tongue is hooked into the slit to a locking position upon erecting the blank, with the inner end of the tongue being passed through the second slit and locked by the portion of the end of the first end flap between the first end flap folding line and the second slit.

3. A blank for a carton box or tray having side walls extended at their ends with end flaps foldable along hinged folding lines at the respective corner of the box, a locking slit being provided at the hinged folding line of the one end flap, and the other end flap forming a locking tongue which is insertable into the locking slit and lockable in it, characterized in that one side of the locking tongue starts from the outer end of the hinged folding line of the tongue, and forms a wedge-shaped space or gap with adjacent side wall, that in the vicinity of its inner end the gAp has a width which is preferably approximately double the thickness of the blank, that one side of the gap forms the edge of a shoulder-shaped portion, and that the distance from the corner point, lying at the ends of the hinged folding lines of the side walls, to the outer end of the slit is approximately the same as the distance from said corner point to the bottom of said wedge-shaped gap, so that the side wall of the tongue must be bent in order that the shoulder-like portion of the tongue can be hooked into the slit to a locking position on erecting the blank; said tongue being provided with a short neck, the inner end of which is hingeable along the hinged folding line of the tongue, and the length of which is preferably approximately the same as double the thickness of the blank, that the inner side edge of the neck merges into a locking edge parallel with the hinged folding line, said locking edge line connecting with the inner end of the adjacent side edge of the tongue so that the corner portion of the tongue between the locking edge and the inner side edge of the tongue forms a free flexible corner flap, that the locking slit in the other end flap lies between an outer and an inner portion of the hinged folding line for this end flap, and is composed of an outer straight slit portion and an inner slantingly directed slit portion, that the outer slit portion is parallel with the end flap hinged folding line, but is placed sideways relative to it, that the outer end of the straight slit portion connects with the outer portion of the hinged folding line of the end flap via a slit end portion, that the slanting slit portion is taken up in the end flap and forms an acute angle with the inner portion of the hinged folding line and has an end portion at its outer end which extends in towards the inner portion of the end flap hinged folding line, that the inner end of the straight slit portion connects with said end portion, and that the distance from the transition between the straight slit portion and the slanting slit portion to adjacent hinged folding line between the side wall and the box bottom is substantially the same as the distance between the inner end of the hinged folding line of the tongue and the hinged folding line between the associated side wall and the box bottom, so that on erecting the box and inserting the locking tongue in the locking slit the flexible corner flap of the tongue will pass through the slanting slit portion while the corner flap is bent sideways, said flap snapping back in again, and over the end portion of adjacent portion in the totally inserted position of the tongue, to a locking position.