A beak-type lock particularly useful for an egg carton includes an upstanding latching member having a horizontal rib at its latching surface, which latching member is adapted to engage an orifice having a shoulder at its bottom margin and a recessed upper margin, and wherein the upper margin in the locking position falls behind a portion of the upstanding latching member to provide a double-acting lock.

FIELD OF THE INVENTION 
The present invention relates to providing improved locking functions for 
molded containers and cartons, and, more particularly, to beak-type locks 
which combine improved strength and resistance to accidental opening. 
BACKGROUND OF THE INVENTION 
In the past, the carton designers of molded cartons have produced cartons 
with beak type locks. However, such prior designs and constructions have 
relatively weak engaging surfaces and are subject to rupture and failure 
when opening is attempted. In some instances the beak formed on the base 
or tray section fails and in other instances the orifice formed in the 
front wall of the cover section ruptures. The problem of failure and 
rupture was ever present in prior constructions. Although, over the years, 
many good designers attempted to produce improved locks, failures and 
ruptures still occurred and the problem was not completely solved. 
Examples of prior designs appear in the U.S. Pat. Nos. to Alsman, 
3,217,963; Friday, 3,245,600; Hartman, 3,276,656; Bagay, 3,459,360; and 
Seest et al, 3,471,078. In esch of these prior designs, developed over the 
years, and with practical experience, the orifice engagement surface 
remained simple. Seest et al. attempted to reinforce their beak with a 
horizontal rib at the very top thereof away from the latch engaging 
surface. It was not obvious to any of the prior workers in the field to 
provide a horizontal peripheral rib at the engaging surface or a vertical 
surface extending upwardly therefrom. 
Many of these prior carton locks may also be relatively easily disengaged 
by movement of the cover section forward relative to the base section of 
the carton. Bagay U.S. Pat. No. 3,459,360, however, discloses the 
interengagement of the back of the beak with the top of the opening. 
RELATED INVENTION 
In U.S. Pat. No. 4,383,638, issued May 17, 1983, a beak-type lock of 
improved strength is provided which overcomes may of the deficiencies of 
the prior art such as discussed above. 
A remaining problem, however, manifests itself when the aforementioned lock 
is used in 18-egg molded egg cartons (3 rows of 6 eggs each) which egg 
cartons, packed with eggs, are displayed on inclined racks with a similar 
loaded egg carton stacked thereabove, so that there is exerted on the 
front wall of the bottom egg carton a considerable force from above. Under 
these circumstances, the weight of the accumulated filled egg cartons 
above the bottom one exerts a force on the beaks of such bottom carton 
which, under rare circumstances, may cause the lock to accidentally become 
undone. 
SUMMARY OF THE INVENTION 
It is, accordingly, an object of the invention to overcome deficiencies in 
the prior art, such as indicted above. 
It is another object to provide for improved locking of molded containers 
and cartons. 
It is still another object of the invention to provide an improvement to 
the carton lock construction of U.S. Pat. No. 4,383,638. 
It is another object of the invention to provide a beak-type lock for a 
molded container or carton, which lock has improved security, i.e. 
increased resistance to accidental opening. 
It is still a further object to provide a lock which, while it has improved 
security, is simultaneously easier and more convenient for the consumer to 
open. 
In accordance with the invention, a molded carton is provided with strong 
locks each including an upstanding relatively fixed beak-like locking 
member formed on the carton tray section and adapted to engage the lower 
margin of an orifice in the front wall of the cover of the carton. The 
upper margin of the orifice is constructed in relation to the upper 
portion of the beak so as to fall therebehind after the locking has been 
completed so as to provide a double-acting lock which inhibits inadvertent 
unlocking by providing interengagement between the back upper portion of 
the beak and the upper margin of the orifice.

DETAILED DESCRIPTION OF EMBODIMENTS 
Referring to the Figures, a carton or box or container 10 formed of molded 
material, for example molded wood or paper pulp or thermo formed foam 
plastic, is shown which incorporates one embodiment of the improved 
beak-type lock. The carton includes an upper cover sometimes referred to 
as cover section 12 and a lower tray sometimes referred to as tray section 
14 which is hingedly connected at its rear to the cover 12. The tray 14 
has a front wall 16 recessed inwardly at 18 to define on the interior 
thereof one or more pockets or cells for accommodating eggs or the like. 
Extending upwardly from the inwardly recessed portion 18 is a latching 
member or beak 20 which generally conforms in structure to that shown in 
U.S. Pat. 4,383,638, mentioned above. As best shown in FIGS. 3 and 5, the 
beak 20 assumes a fixed position relative to the remainder of the tray 
section and is substantially hollow with side walls which taper downwardly 
and outwardly from the top of the beak to an integral horizontal 
peripheral rib or flange 22 rounded at the top and sides thereof. 
The cover 12, in turn, is formed with a front wall 24 which may be 
scalloped such as shown in FIGS. 2 and 3, or which may otherwise have one 
or more suitable indented or depressed areas 24a within which is formed an 
orifice or female or latching formation 26 adapted to cooperate with the 
male latching member or beak 20 to effect locking of the cover in a closed 
position, see FIGS. 1 and 2. The orifice 26 has a lower margin formed as a 
shoulder 28 with which the rib 22 of the beak 20 is adapted to engage. 
Such shoulder 28 may be formed with a thickened middle portion 28a to 
increase the contact area and also the strength of that portion 30 of the 
front wall 24 of the cover 12 underlying the opening 26, as will be 
discussed in more detail hereinafter. 
In general, orifices or female locking formations according to the present 
invention are constructed such that, in the locking position as 
illustrated in FIGS. 1, 2, 4 and 5, at least a portion of the upper margin 
25 of each opening, which corresponds to the lower edge of the front wall 
portion 24a, falls at least particularly behind the male beak 20 in such a 
way that to as upper margin portion 25 interferes with the top of the beak 
and prevents accidental or inadvertent unlatching of the carbon due to 
relative forward movement of the cover section 12 with respect to tray 
section 14. 
In the preferred embodiment, the upper margin 25, the shape of which is 
best seen in FIGS. 3 and 6, has a configuration which is generally 
complementary to the shape of the male beak 20, the central part being 
generally of an inverted U-shape, with the ends tapering outwardly and 
downwardly. As best seen in FIG. 7, however, the inverted U-shaped portion 
is somewhat narrower than the width of the beak 20 and therefore a pair of 
ears or flaps 34 are created, and it is these ears 34 which constitute the 
portions of the upper margin 25 falling behind the male beak 20. It will 
be understood, however, that other shapes and configurations are possible, 
e.g. the opening may be substantially rectangular with its upper edge 
being generally straight and parallel to the shoulder 28. 
Regardless, the orifice 26 extends in and between two planes, namely a 
rearmost plane in which the indented portion 24a of the front wall 24 of 
the cover 12 lies (see FIGS. 4 and 5), and a frontmost plane defined by 
other portions of the front wall 24 of the cover 12, including that 
portion 30 sometimes referred to as a depending band which lies below the 
shoulder 28. Thus, two side margins 32 of the orifice 26, and the lower 
margin formed by the shoulder 28, are generally in the same plane, while 
the upper margin 25 of the orifice 26 is recessed inwardly. 
On a level with the lower margin of the orifice 26 formed as the shoulder 
28, at least a portion of the horizontal peripheral rib 22 of the beak 20 
extends thereover when the beak 20 is in latching engagement. Formed 
integrally with the shoulder 28 is the depending band 30. As noted above, 
the thickened portion 28a of the shoulder 28 serves to enhance the 
effectiveness of the locking engagement. 
During the locking operation, the rounded tip of the beak 20 first comes 
into contact with the lower portion of the depending band 30 as the cover 
is pivoted to a closed position causing the band to deflect outwardly; as 
the closing movement continues, the shoulder 28 of the cover section 
deflects outwardly over the beak 20 and finally over the horizontal 
peripheral rib 22 thereof. As this occurs, the beak 20 clears the center 
uppermost portion of the margin 25 and the ears 34 flex over the rounded 
sides of the beak 20 and come into engagement with the back of such beak, 
thereby providing a double-acting lock, i.e. the normal beak-locking 
mechanism plus the second locking effect between the back of the beak 20 
and the ears 34. This double-acting lock prevents inadvertent unlocking by 
pressure on the beak. To effect carton opening, the user needs only to 
pull outwardly the depending band 30 until the shoulder 28 clears rib 22 
and then pivot the cover upwardly to the open position; such a motion most 
users find natural. In this illustrated embodiment, the upper margin 25 of 
the opening 26 in the center thereof should extend above the top of the 
beak 20 as shown in FIG. 7 to allow the ears 34 to flex if required during 
closure. 
The molded containers and cartons on which the latching formation in 
accordance with the instant invention is useful include egg cartons, food 
containers such as boxes for sandwiches, chicken parts, pizzas, and 
hamburgers in fast food operations, and other food articles and other 
items. 
It will be understood that in accordance with the instant invention novel 
forms of beak-locks have been described which include latching engagement 
surfaces of particular formation which will resist tearing stresses and 
other forces encountered during closing and opening operations which may 
be manual or automatic. Also in accordance with the invention the latching 
engagement surface associated with the orifice with which the beak engages 
has been particularly formed so as to obviate failure due to rupture when 
the containers or cartons incorporating the lock are opened or closed. In 
particular, the male beak interacts with the female aperture in such a way 
as to provide a double-acting lock. 
The foregoing description of the specific embodiment described will so 
fully reveal the general nature of the invention that others can, by 
applying current knowledge, readily modify and/or adapt for various 
applications such specific embodiment without departing from the generic 
concept, and, therefore, such adaptations and modifications should and are 
intended to be comprehended within the meaning and range of equivalents of 
the disclosed embodiment. It is to be understood that the phraseology or 
terminology employed herein is for purposes of description and not of 
limitation.