US3126142A - Corner lock fibreboard container - Google Patents

Description

March 24, 1964 R, GQETZ 3,126,142

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INVENTOR. ROBERT L. GoETz YM WMMSWXM wah/d United States Patent 3,126,142 CORNER LOCK FIBREBOARD CONTAINER Robert L. Goetz, Dallas, Tex., assignor to Inland Coni tainer Corporation, Indianapolis, Ind., a corporation of Indiana Filed July 5, 1962, Ser. No. 207,646 1 Claim. (Cl. 229-36) This invention relates generally to containers ofthe type customarily made of corrugated or uncorrugated fibreboard and inparticular vto a carton vor' container formed from a die cut sheet which when closed forms self-locking corner posts.

In the past corner` reinforced containers have been designed wherein cornerlocking flaps, formed at vthe junction ofthe end panels .andside panel. of the container are folded diagonallyuupon themselves. Such structure is illustrated in AndrewsPatent 2,713,962. While such diagonal fold corner reinforcement stabilizes the corner structure and can accommodate locking tabs extending from the top panel, it does not add to the stacking strength of the carton. Such stacking strength is of considerable importance in applications where a relatively light weight carton is utilized with contents which cannot survive any substantial compressive load. An example of such carton applications is the packaging of bakery goods and the like.

The structure of the present invention provides a corner fold structure which not only stabilizes and reinforces the carton corners but also reinforces the carton to greatly increase its stacking strength. The corner locks are formed by providing an L-shaped cut and a diagonal score line in locking aps formed at the junctions of the end and side panels. Matching tabs are also formed to extend sidewardly from the top panel and when the locking flaps are folded upon themselves, the tabs are received within the fold providing a lock or retention of the top panel in overlying position with relation to the base panel. The arrangement is such that the carton may be reused.

The primary object of the present invention is to provide a carton formed from a die cut sheet and designed so that when folded and closed, the carton is provided with self-locking corner posts, the corner posts serving to add additional strength to the carton as well as ease in closing, this being accomplished without the use of tape, stitching or glue.

These and other objects will become apparent as the description proceeds with reference to the accompanying drawings in which:

FIG. l is a top plan view of a die cut sheet from which the container of the present invention may be fabricated.

FIG. 2 is a perspective view of the container after it has been folded or seteup but before the top panel has been lowered into closed position.

FIG. 3 is a fragmentary perspective view illustrating the position of the corner components as the top panel is moved into closed position.

Referring initially to FIG. l, the blank from which the carton is formed has a generally rectangular overall configuration. The blank is transversely scored at 10, 11 and 12 to provide a top panel 13, a rear, side panel 14, a base panel 16 and a front, side panel 17. A score line 18 crossing the top panel 13 defines an extending flange 19. The liange 19 may be omitted from the structure or may be formed integrally with the outer margin of the front panel 17, the actual presence of the fiange 19 and its location forming no part of the present invention. The side marginal areas of the top panel 13 are scored at 21 and cut along the line 22 to provide sidewardly extending tabs 23. The score lines 21 form the lines of junction between ice 2 theV tabs 23 and the top panel 13-.and the cut 22 has a configurationsuch that the tabs 23 have a marginal portion 24 which is inclined with relation `to the line of junction 21 with the top panel.

The longitudinal cuts` 26 and 27 define side locking fiapsZS and 29 respectively, the aps 28 and t29 having notches 28a and 29a formed therein which are adapted to interfit in setting up the container ,as will subsequently be described. The base panel 16 is scoredat 31 and 32 to define end panels 33, the junction between the end panels and the locking liapsy 23 and 29 being defined byA score lines34 which are in effect extensions of the score line11.

Transverse score lines36 extend across the front panel 17 and are substantiallyaligned with the junction ofthe end panels33 and the base panel l16 as defined by the score lines 31 and 32. An L-shapedvcut is formed in each of the end panels, one leg 37 of the cut being substantially aligned with the Yjunction ofthe front panel 17 and the base panel 16 as defined by the score line 12. The cut terminates short of the outer margin of the end panel and further score lines 38 extend from the extremity of the leg 37 of the cut to the outer margin of the end panels. The transverse score lines 36, the further score lines 38 and the leg 37 of the L-shaped cut define generally rectangular locking aps 39. Diagonal score lines 41 extend from the extremity of the other leg 42 of the L-shaped cuts to the adjacent corner of the locking fiaps 39. The score lines 41 are shown in FIG. 1 as double lines, however, it will be understood that these might be of various spacing or might be a `single line, all such alternatives being included by reference herein to the score lines 41.

Referring to FIGS. 2 and 3, the container may be set up by folding the end and side panels along the proper score lines into positions normal to the plane of the base panel 16. The side locking fiaps 28 and 29 may be folded inwardly along the score lines 34 and locked by interfitting the notches 28a and 29a as indicated in FIG. 2. The tabs 23 are folded sidewardly along score lines 21 so as to extend generally normal to the plane of the top panel 13.

The corner structure is formed by folding the locking fiaps 39 upon themselves along the transverse score lines 36, the score lines 3S and the diagonal score lines 41, as indicated in FIG. 2, so that the locking flaps 39 overlie the adjacent end panels 33. The locking flaps are retained in this folded condition by insertion of the tabs 23 as indicated in FIG. 3. As there shown, in closing the top panel 13 into spaced overlying relation with the base panel 16 the tabs 23 are inserted between the locking liaps 39 and the adjacent face of the end panels 33 so that both the tabs 23 and the locking fiaps 39 overlie the adjacent faces of the end panels 33. Although the tab 23 is shown in intermediate position in FIG. 3, it will be understood that when seated the inclined margin 24 of the tab 23 will be seated against the inclined scored area 41 and will thereby retain the corner structure in folded condition.

From the foregoing it will be evident that the structure of the present invention provides a relatively light weight carton, die cut from a `single blank, and having a corner lock structure which provides substantial reinforcement of the container for resistance to compressive stress such as occurs in stacking of the containers. The assembly of the carton is such that it may be opened and reclosed repeatedly without causing visible deformation or deterioration of the carton structure.

While the invention has been disclosed and described in some detail in the drawings and foregoing description, they are to be considered as illustrative and not restrictive in character, as other modifications may readily suggest themselves to persons skilled in this art and within the broad `scope of the invention, reference being had to the appended claim.

The invention claimed is:

A reinforced corner lock carton including a top panel adapted to be closed in spaced overlying relation to a base panel, tabs extending outwardly from each side margin of said top panel and adapted to be folded along their lines of junction with the top panel into planes normal to the plane of said top panel, said tabs having a generally rectangular shape the free edge of which is aligned with said base panel, end panels extending outwardly from each side margin of said base panel, a front panel extending outwardly from one end margin of said base panel, said end and front panels being adapted for folding into planes normal to the plane of said base panel, a transverse score line extending across said front panel adjacent each of its ends and substantially aligned with the junction of said end panels and base panel, an L-shaped cut formed in each of said end panels, one leg of said cut being substantially aligned with the junction of said front and base panels and terminating short of the outer margin of said end panels, the other leg of said cut extending normal to said one leg and terminating short of the outer margin of said front panel, further score lines extending from the extremity of said one leg of said cut to the outer margin of said end panels, said transverse score lines, said further score lines and said one leg of said cut dening locking flaps, and a diagonal score line extending from the extremity of said other leg of said cuts to the adjacent corner of said locking aps, whereby when said end panels and front panel are folded normal to said base panel said locking flaps may be folded upon themselves along said transverse score lines, said further score lines and said diagonal score lines to provide a generally rectangular configuration for said locking flaps and disposing them in overlying relation to the adjacent end panels.

References Cited in the le of this patent UNTTED STATES PATENTS 1,111,552 Allers Sept. 22, 1914 1,544,311 Gaffenberger June 30, 1925 1,985,778 Himes Dec. 25, 1934 2,311,403 Lighter Feb. 16, 1943 2,354,600 Kretchmer July 25, 1944

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