US3601306A

US3601306A - Locking mechanism for egg cartons

Info

Publication number: US3601306A
Application number: US841721A
Authority: US
Inventors: Theodore P Martens; James R Patton
Original assignee: Sinclair Koppers Co
Current assignee: Atlantic Richfield Co; Sinclair Koppers Co
Priority date: 1969-07-15
Filing date: 1969-07-15
Publication date: 1971-08-24
Anticipated expiration: 1988-08-24

Abstract

A locking mechanism for an egg carton having an integrally hinged tray and cover. The locking mechanism includes a locking flap hingedly connected to the cover and foldable into overlapped relation with the inside of the cover''s front wall and locking detents projecting inwardly from the inner surface of the folded flap. The carton is secured shut by interlockingly engaging the locking detents with the underside of a raided lip on the front wall of the carton''s tray.

Claims

1. A packaging carton comprising a bottom section having a front wall and a rear wall; a cover section having a front wall and a rear wall, the cover and bottom sections'' rear walls being hingedly connected so that the cover section can assume a closed superimposed position with respect to the bottom section; and interlocking means on the front walls of the cover and bottom sections for releasably holding the carton closed, said interlocking means comprising: a. a locking flap hingedly connected to the bottom longitudinal edge of the cover section''s front wall and foldable into overlapped relation with the inside of the cover''s front wall; b. a plurality of spaced lockin detents projecting inwardly from the inside surface of the flap when it is in substantially folded overlapped position, said locking detents having an upper flat locking edge and depending sidewalls slanting toward the bottom of the locking flap; c. a plurality of spaced lugs projecting upwardly from the top of the front wall of the bottom section, each lug having a recess open at the front for receipt of a locking detent; and d. flat top walls on each of said lugs defining the top of said recess and forming a plurality of spaced locking lips corresponding to the plurality of locking detents; said locking lips engaging the upper flat locking edges of the locking detents as the sections are moved into closed position thereby pivoting the locking flap up into overlapped relation with the inside of the cover section''s front wall and bringing the locking edges of the detents into locking engagement with the underside of the locking lips.

2. The carton of claim 1, in the form of an egg carton with the bottom section having a plurality of egg-accommodating cells.

3. The carton of claim 1, wherein the carton is of unitary molded construction.

4. The carton of claim 3, wherein the molded carton is formed of foamed polystyrene.

5. The carton of claim 1, including a locking flange, coextensive with the locking flap and extending beyond the locking edges of the locking detents, said locking flange abutting the forward edge of the locking lips when the sections are in closed position to hold the locking flap in locked position.

6. The carton of claim 5, wherein the hinged connection between the locking flap and the cover section''s front wall resiliently urges the flap away from the inside of the cover''s front wall so that the locking detents snap into their corresponding recesses in the lugs when the sections are moved into closed position.

7. The carton of claim 5, in which the hinged connection between the cover and bottom sections'' rear wall resiliently urges the sections apart so that the locking detent''s upper locking edges snap into tight engagement with the underside of the lugs'' locking lips when the sections are moved into closed position.