IE54774B1 - Moulding carton locking system - Google Patents

Abstract

A locking system used with a moulded carton e.g. for eggs has a lock flange 13 moulded in the upwardly projecting direction and attached to the base 11 of the carton and a protrusion 16 on the lock flange 13 which fits into an opening 17 in a cover 12. For additional engagement security, an indent 21 on the lower lip of the opening 17 engages the bottom surface 22 of the protrusion 16. A creased hinge line 23 joins the lock flange 13 and base 11 and compressive pressure exerted by abutments 40 maintains an engaging force of the protrusion 16 with the opening 17 through which it extends. <IMAGE> [GB2128962A]

Description

cartons and more This invention relates to particularly to a locking system to maintain an egg carton in a closed position during handling and storage.

Egg cartons in prior art utilize locking devices to 5 prevent spillage of eggs from the carton during handling of the cartons. These have been used on cartons of different materials including molded pulp material, paperboard, and various forms of molded plastic.

Locking systems utilizing beak-shaped locks are known 1C in molded cartons wherein a beak-shaped protrusion, projecting upwardly from the base, enters an opening or recess or the like on a side of the cover to hold the cover shut until the beak is pushed inward to release it from the cover.. Structures of this type are shown in USP's 3,217,963; 3,276,656; 3,459,360; 15 3,469,764; 3,471,078; 3,531,039; 3,570,747; 3,572,578; 3,672,560; 3,672,693; and 3,749,235. Without denigrating the prior structures, it should be noted that they, in general, do not provide sufficient egg protection from vertical forces because of the absence of a bracing flange. In addition, 20 due to molding requirements, the "beak" has usually been so located that the material below the mating opening in the front wall of the cover easily tears. These prior cartons have not, in general, been formed with bracing flanges because of the difficulty in molding such a structure.

A further problem with a fixed male "beak" lock, is the need to target the location of the cover edge closely to the beak locking face, in order to effect easy and secure closure. Failure to properly target such locks may interfere with the requirements of automation handling.

The lock form of the present invention i s operated like the familiar button lock of the prior art and is therefore easy and natural for consumers to use. It incorporates a minimally rotatable bracing flange to support the locking lugs.

This lock form may be used with a variety of different package configurations holding the different numbers of eggs of these configurations and operates with existing automation equipment used with all these configurations.

The lock form having an upright molded locking and 10 bracing flange saves space during its manufacture and lowers costs. It saves space on the molding maching thus allowing more productivity per machine hour, and its construction permits it to be easily molded. It also saves space on erecting equipment which may be important on larger sizes 15 near a critical fit.

Reliability of this new lock form is improved since the new lock is part of the nested portion and is less subj ect to damage than prior art extended forms. The bracing flange also helps to protect the carton from vertical 20 compression which would cause egg breakage.

The lock form of the present invention produces more secure locking because of its greater tendency to remain engaged than extensively prefolded hinged locks of the prior art.

The lock of the present invention includes a lock flange which is molded upright as an extension of the natural nesting wall angle of the carton and can be mechanically pre-folded inwardly to establish the proper operational locking angle.

Unlike the famous molded button-lock cartons commonly in use today wherein the locking flap is molded in the same plane as the open carton, whereby in use the flap is rotated -2- more than 90° to fit inside the carton cover, in the present carton the flange hinge is of a character which permits rotation of the upright molded flange only a maximum of about 40°, preferably not more than about 35°.

The connected web forming a bellows foldable connection of the new lock to the cell base, differs from prior art in its initially upright molded position - also in the fact that the new flap is only free to rotate iiwardly through a bending range up to 40° from its initially molded position. Unlike prior 10 art, the lock cannot be folded outward without destroying its function.

This limited movement is enough to insure that the lock can be moved to target to the cover during automation closure, overcoming the lack of targeting of the beak-type 15 lock.

The lock flange in an embodiment of the present invention includes a protrusion or lug thereon engaging with a protrusion on the bottom edge of the lock opening for greater lock engagement and security. .

The lock flange of the present invention also includes a hinge assembly with an area of reduced thickness which also interacts with the front cover wall.

The lock of an embodiment of the present invention also has further advantages of additional stacking strength, 25 i-e. bracing, due to engagement of the top edge of the locking flange and cover.

In the lock of the present invention, abutment forms come into action as the lock flange is bent inward, forcing a stop to rotation of the lock flange and insuring continuing 30 lock projection through the cover lock openings. -3- ->47 7 7 These as well as further advantages which are inherent in the invention will become more apparent from the following description, reference being had to the accompanying drawings wherein: 5 FIGURE 1 is a side elevation of an egg carton embodying the lock of the present invention showing the carton in a wide open position; FIGURE 2 is a partial perspective enlarged view of the lock flap portion of FIG. 1 viewed from the outside of 10 the carton; FIGURE 3 is a partial perspective further enlarged view of the lock flap portion of FIGS. 1 and 2 viewed from the inside of the carton; FIGURE 4 is a section view of the lock flange of 15 FIG. 3 along line IV-IV; FIGURE 5 is a reduced size, in comparison to FIG. 2, partial perspective view of a portion of the cover which fits over the lock flange of FIGS. 1-4 as viewed from the outside of the cover of FIG. 1; FIGURE 6 is a partial sectioned view along lines VI-VI of FIGS. 2 and 5 with the cover over the lock flange; FIGURES 7A-7B show the compression effect that forms a bellows fold in the thinned area of the lock structure; FIGURES 7C-7D show an alternative lock form in which 25 the "thin bellows" area is not present - the lock rotation inward terminates when the lock flap shoulders contact the cell shoulders; FIGURE 8 is a sectional view of another embodiment showing the interrelationship between the locking elements; 3C and FIGURE 9 is a partial perspective view of the front cover, showing the locking opening, in the embodiment of FIGURE 8.

Referring first to FIG. 1, there is shown a side elevation of a molded carton H) using the lock form of the present invention. In the illustrated case an egg carton is shown, although the lock form is not necessarily limited 5 in its use to only egg cartons. Egg carton 10 has a base 11 with cover 12 attached hingedly to one longitudinal edge and a lock flange 13 along the opposite longitudinal edge in a position to lock cover 12 in a closed position.

As shown in more detail in FIG. 2, 3 and 6, lock 10 flange 13 is hingedly connected to base 11. In the open position of FIG. 1, carton 10 is in the position for nesting of other cartons 10 within it. The upright molded lock flange 13 may optionally have an offset 15 along its top edge to aid in nesting of vertical flange sections 13.

Lock flange 13 has lock protrusions 16 along the top edge of lock flange 13 to coincide with lock openings 17 in cover 12 as shown in FIGS. 5 and 6. Beneath each lock protrusion 16 on the lock flange 13 .is a vertical .depression 38’ which serves to increase the depth of the horizontal 20 bottom surface 22 of the lock protrusion 16.

One of the means of obtaining more secure locking of the cover 12 to lock flange 13 is illustrated in the shape of indent 21 in the bottom lip of lock opening 17. Indent 21 extends inwardly under bottom surface 22 of lock protrusion 25 16 and allows the cover 12 a better hold on lock protrusion 16.

Uhen top cover 12 is closed downwardly on lock flange 13, lock flange 13 which has been in a substantially upright position must bend inwardly along a hinge line 23 and must only partially return when lock protrusion 16 passes into lock 30 opening 17. To accomplish this smoothly, lock flange 13 must have sufficient flexibility to bend along hinge line 23 but must also have enough return force to keep all lock protrusions 16 extending into, and securely remaining in respective openings 17. Several hinge line formations that can produce 35 this result are illustrated in FIGS. 2,4,6 and 7A-7D. -5- FIG. 4 shows a cross-section through a lock flange 33 and hinge line 34 showing a thinned area 35 that slants inwardly of the carton 10 toward its top edge. This thinned area extends over lock flange indent designated by dimension line 36 in FIG. 3. FIG. 3 shows the rear of lock flange 33.

As the lock flange 33 is folded inwardly, scoring or bending is controlled by the thin area along dimension lines 37 which thin area is basically in tension along hinge line 34.

The thin material along dimension line 36 goes into compression as the lock flange indent tip 38, which constitutes the opposite side of the vertical depression 38', swings in, until indent tip 38 and the lower edge of the flange 13, connected at line 36, come to rest (see FIG. 2) against cylindrical abutment forms 40 at the top of the base 11 under the lock flange 33. Thus, the bottom outside edge of the flange 33 defines a scalloped edge 45 which, as the upper part of the flange 33 rotates inwardly becomes forced against the abutment forms 40, the latter acting as a flexible stop which, due to the memory of the material from which the carton is formed, creates a spring return action on the flange resisting further inward movement and driving the flange outwardly. This restricts the amount of fold angle possible for the lock, thus insuring that the lock will stay in a tight relationship with maximum projection of lock protrusion 16 through lock openings 17.

In FIG. 6 a similar bending action and return force takes place upon closing of the cover. In this case a crease is formed along hinge line 23.

FIGS. 7A-7B schematically show the folding action of the preferred lock form. Here the hinge line is molded as a thin web 43 which folds like a bellows upon inward movement of the lock flange thus helping to create the return locking force.

The resistance of making this bellows fold combines with the abutment of forms 40 to help insure lock return force.

FIGS. 7C-7D schematically show alternative forms wherein wherein there is no hinge at all, i.e. instead, there is a gap 42, along the area corresponding to line 36 in FIG. 3. -6- FIGURES 8 and 9 illustrate a variant of the locking elements, wherein the wall 52 of the front cover extending immediately above the locking opening extends in a plane spaced inwardly from the remainder of the front wall of the 5 cover portion, so that the bottom forming edge 51 of such locking opening is spaced outwardly compared to the upper edge 53 of the opening. In addition, the vertical dimension, i.e. the height of the opening is reduced and as best seen in FIG. 8, the height of the locking lug 56 is greater than 10 the height of the locking opening.

As the lock becomes engaged in the embodiment of FIGS. 8 and 9, edge 51 deflects outwardly as it is pushed over the lug 56, and edge 53 falls behind the lug 56 to prevent inadvertent inward movement thereof. This variant 15 therefore provides a double-acting lock, the engagement of the edge 51 with the bottom of the locking lug, in combination with the hinge urging the bracing flange in the forward direction, providing a first locking action; and the engagement of the back of the lug 56 with the lower part of the wall 52 providing a 20 second locking effect. To effect opening of the carton, the edge 51 must be lifted over the locking lug 56, a motion most customers find natural.

It will be obvious to those skilled in the art that various changes may be made without departing from the scope 25 of the invention and the invention is not to be considered limited to what is shown in the drawings and described in the specification.

Claims (16)

1. A moulded carton comprising a base section having an open top; a cover section adapted to overlie and close said open top, said cover section including a rear wall, an apertured front wall, and end walls interconnecting said rear wall and said front wall and a lock system for locking the cover section in said overlying closed relation, said lock system including a hinged flange moulded and mounted in an upright position on a front segment of the base section defining the open top for only limited inward pivotal movement from the normal moulded upright position wherein said flange projects generally upwardly from the front of the base section, a front surface of the flange being provided with a predetermined number of protrusions projecting through and interlocking with a corresponding number of apertures formed in the cover section froftt wall when said flange is pivoted inwardly from said normal upright position and resiliently engages an interior surface of the cover section front wall when said cover section overlies and closes the base section open top.

2. The carton of claim 1 wherein a portion of the flange front surface disposed beneath at least one protrusion is recessed and the base section is provided with means in close proximity to and beneath the flange recessed portion U ·* U ·* 5 for engaging the underside thereof and limit inward hinged movement of the flange from its normal moulded upright position, the means, when engaging the flange recessed portion, imparting a reactive force on said flange urging same against the cover section front wall and effecting interlocking engagement between the predetermined number of flange protrusions and the corresponding apertures of the cover section front wall. 10 15

3. The carton of claim 1 wherein the cover section is hingedly connected to a rear segment of the base section defining the open top, said cover section being moulded in a laterally offset position relative to the base section open top, and the lock system flange being moulded on the front segment of the base section open top so as to normally project generally upwardly from a plane defined by the front and rear segments of the base section open top. 20

4. The carton of claim 1 wherein portions of the cover section front wall disposed above the apertures formed therein are recessed to the remainder of said front wall.

5. The carton of claim 2 wherein the means on said base section substantially limits inward pivoting of the lock system flange to about 40 degrees from its normal upright position.

6. The carton of claim 1 wherein the protrusions are - 9 - 25 ij A formed adjacent an upper edge of the flange and the portions of the flange disposed beneath the protrusions are recessed.

7. The carton of claim 4 wherein the protrusions of the flange, when in interlocking relation with the cover section front wall apertures, have segments thereof extending above the peripheries of said apertures.

8. The carton of claim 6 wherein the recesssed portions of the flange beneath the protrusions are connected to the front segment of the base section by web portions which define in part the hinge line of the flange.

9. The carton of claim 6 wherein the flange hinge line is interrupted by gaps disposed in aligned relation with recessed portions of the flange.

10. A locking system for a moulded carton such as an egg carton having a base section and a cover section hingedly connected thereto, said system comprising a lock flange attached to an edge of the base section opposite from an edge to which the cover section is hinged and moulded to normally project upwardly and to pivot inwardly only; a hinge portion at the junction of the base section and the flange; a lock protrusion on said flange; a lock opening in the cover section positioned to receive said lock protrusion; and means for producing a force on said flange to keep said protrusion engaged in said lock opening when - 10 - the cover section is overlying the base section.

11. A moulded and nestable egg carton including a locking system, said moulded and nestable egg carton comprising a cellular base for receiving and holding a plurality of eggs; a cover hingedly connected to said base; a lock flange attached to the opposite edge of said base from said cover and being moulded to normally assume an upwardly projecting configuration and being withdrawable from a mould in which it is formed; a lock protrusion on said lock flange; a lock opening in said cover positioned to receive said lock protrusion; and a non-linear scalloped hinge along the juncture of said base and flange, said hinge permitting rotation of said lock flange only inwardly a maximum of about 40 degrees, said scalloped hinge including means to produce a force including a compressive force on said lock flange to keep said lock protrusion engaged in said lock opening.

12. The egg carton of claim 11, further wherein said lock opening leaves an indent on the lower lip of said lock opening for engaging with said lock protrusion.

13. The egg carton of claim 11, further wherein the front wall of the cover has a wall extending upwardly from the lock opening, said wall being spaced inwardly of the remainder of the front wall of said cover so that said wall above the opening is recessed, the height of the 11 - opening being less than the height of said lock protrusion, whereby when the carton is locked the upper part of the lock protrusion extends above and in front of the bottom of said recessed wall above the lock opening.

14. The egg carton of claim 11, wherein said means to produce a force on said lock flange to keep said lock protrusion engaged in said lock opening, includes semi-cylindrical abutment forms at the top of said base and under said lock flange adjacent said scalloped hinge, whereby, as the upper part of said flange rotates inwardly, said scalloped hinge becomes forced against said semi-cylindrical abutment forms thereby creating a spring return action on said flange which in turn causes resistance against further inward movement of said flange.

15. A moulded carton substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings. MACLACHLAN & DONALDSON, Applicants' Agents,

16. 47 Merrion Square, DUBLIN 2.