US3138313A - Carton - Google Patents

Description

June 23, 1964 R. F. REIFERS ETAL 3,13

CARTON aluminum .mm nw mnuw l unmuu 2o 6 se Use a .42

Ri 0rd E Reife nry A. Lo

FIG.9. I INVENTOR ATTORNEY June 1964 R. F. REIFERS ETAL 3,133,313

CARTON Filed Feb. 5, 1962 2 Sheets-Sheet 2 INVENTOR Richard F. Reifers &

Henry A.Lord

W ATTORNEY United States Patent 3,138,313 CARTON Richard F. Reifers, New Canaan, Conn., and Henry A. Lord, Palmer, Mass., assignors to Diamond National Corporation, New York, N.Y., a corporation of Delaware Filed Feb. 5, 1962, Ser. No. 171,174 8 Claims. (Cl. 2292.5)

This invention relates generally to containers and more particularly to improvements in molded pulp articles and methods of affording such improvements.

Typical containers of the character involved are disclosed in US. Letters Patent to Reifers #2,888,183, issued May 26, 1959, which are desirable for the purpose intended. However, there has been a continuous effort to attain greater strength per weight of pulp fiber used during the manufacture of containers or cartons of the character involved, more positive locking, and structural strength in the movable parts which are susceptible to mechanical deformation.

Additionally, there is a continuous efi'fort to improve manufacturing techniques whereby conventional equipment can be used and the quality and performance of the product can be increased without increased cost in the production of the product or substantial modification to the conventional apparatus.

A primary object of the present invention is to provide an improved molded pulp carton which affords greater dimensional control of the finished carton, especially during drying, provides pre-stressing in certain carton sections that may be subject to mechanical deformation when manipulated during opening or closing of the carton, and which substantially eliminates the natural direction of warpage of relatively thin planar sections of the carton to maintain the various cooperating parts in an optimum oriented position.

Another object of this present invention is to provide novel lock means in cartons of the character involved which provides a double lock.

A still further object of the present invention is to provide a novel method of pre-stressing integrated pulp fiber of an article preform for resisting mechanical deformation which occurs during manipulation of the cooperating parts of the lock structure of the carton.

Although the exemplary embodiment of the invention is disclosed in relation to molded pulp egg cartons, the principles of the invention are readily adaptable to other types of cartons generally having the same structural and functional characteristics as that illustrated by the abovementioned prior art patent.

Other objects and the nature and advantages of the instant invention will be apparent from the following description taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a fragmentary bottom plan view of the bottom section and lock flap of a carton incorporating the features of the invention;

FIG. 2 is a front elevation of the carton of FIG. 1, prior to the carton being closed;

FIG. 3 is a fragmentary vertical section taken substantially on the plane of line 33 of FIG. 2, showing by phantom lines the manner in which the lock flap cooperates with the lid section when the carton is closed;

FIG. 4 is a section taken substantially on the plane of line 44 of FIG. 2, showing by phantom lines the relative position of a portion of a suction mold screen, and illustrating the three-dimensional reinforcing and prestressing ribs of the lock flap;

FIG. 5 is a front elevational view similar to FIG. 2, showing another embodiment of a carton incorporating the features of the invention and illustrating a novel double-lock used in the carton;

Patented June 23, 1964 FIG. 6 is a vertical section taken substantially on the plane of line 6-6 of FIG. 5, and similar to FIG. 3;

FIG. 7 is a front elevational view similar to FIGS. 2 and 5 showing a further embodiment of the novel carton incorporating the features of the invention;

FIG. 8 is a vertical section taken substantially on the plane of line 8-8 of FIG. 7, and similar to FIGS. 3 and 6; and

FIG. 9 is a fragmentary perspective view of the lock flap of FIG. 7, illustrating by means of direction arrows the manner in which the lock flap is pre-stressed when it is produced.

The present invention is shown in relation to an egg carton or similar container which incorporates a bottom section, lid section and lock flap section, the lid and lock flap sections being articulated with respect to the bottom section so that they will automatically snap lock together in a closed condition, and yet be readily and quickly released for access to the carton contents without inverting the carton.

Referring to the drawings, a molded pulp carton is indicated generally at 10 in FIG. 2 and includes a bottom section 12 formed as a 3 X 4 style molded pulp carton for containing eggs, for example. The carton is molded in any suitable manner, and includes along a forward longitudinal edge a hinge structure 14 connecting thereto a lock flap indicated generally at 16 which is normally biased forwardly of the carton edge to afford a snap-lock function when in a locked condition. Hingedly connected at 18 to the opposite side margin of the bottom section 12 is a lid section indicated generally at 20 which includes a planar top wall 22 and depending rear and front walls 24 and 26, respectively, formed integral with side walls 28 and 30. The bottom section 12 includes a peripheral upper margin 32 abuttingly engaged by the peripheral margin 34 of the top section 20.

The flange 32 is relieved or notched out as indicated at 36 and 38 at opposite ends of the lock flap 16 and a hinge or articulated connection 14 to permit free pivoting of the lock flap 16 toward a locking and unlocking position.

The manner in which the exemplary embodiment of the carton functions is described in detail in the previously mentioned Us. Letters Patent #2,888,183, and accordingly further description of the manner in which the carton functions is believed to be unnecessary.

The lock flap of the embodiment shown in FIGS. 1-4 includes a substantially planar base 40 comprising a single thickness or layer paper pulp fiber having integrated therewith substantially three dimensional pre-stressing and reinforcing ribs indicated generally at 42. The ribs 42 are disposed symmetrically with respect to a laterally projecting abutment or lock button 44 which extends substantially normally from the planar base 40. The outer edges of the lock button 44 are relieved or rounded as indicated at 46 and it is formed with a slight undercut notch or groove 48 for the purpose of positively securing the carton in closed condition. The lock button 44 is disposed inwardly or below the upper edge 50 of the lock flap base 40 to prevent distortion of the carton preform during vacuum transferring of the wet preform from a molding die to transfer dies or drying dies, for example (not shown).

Positioned beneath the lock element or abutment 44 is a reinforcing and pre-stressing portion 52 which extends out of the surface of the planar base 40 and which is substantially three-dimensional.

The pre-stressing and reinforcing ribs 42 include a plurality of angularly extending, symmetrically disposed rib elements or portions 54, 56 and 54', 56', the rib elements 54, 56 and 54', 56 being mutually parallel. Extending from the hinge connection 14 are a plurality of reinforcing feet 58, 60, 62 and 64 disposed in symmetrical relationship to reinforcing feet 58', 60, 62 and 64', respectively. The feet 60, 62 and 64, as well as the feet 60', 62 and 64 are formed integral with mutually parallel leg elements or ribs 66, 68 and 79 and 66, 68 and 70', which terminate at the ends of the angularly disposed rib elements 54, 56 or 54', 56'.

In a finished carton, the rib elements will resist bending in both a vertical and horizontal plane parallel to the hinge 14 or normal thereto, and this function is afforded by the angular relation of the rib element 54, 56 and 54, 56 with respect to the normal bending planes of the planar base 40.

The rib elements have a dual function which affords positive orientation or dimensional control of the abutment lock element 44 during manufacture of the carton, as well as reinforcing by pre-stressing the fiber during the manufacture of the carton. When the lock flap 16 is initially deposited as a layer of pulp fiber on a wire screen as indicated by S in FIG. 4, the screen will have formed therein grooves G which will fill up with the fiber and build over to form the rib elements which will be integral with the substantially planar base 40 and have a threedimensional configuration as clearly seen in FIG. 4.

Considering the prior art disclosure, Us. Letters Patent #2,88S,l83, it will be noted that the lock flap therein is substantially planar. It has been observed during the manufacturing process that when this carton was produced, the substantially planar lock flap tends to warp or bow away from the screen side of the preform inwardly during drying of the carton possibly due to fiber impaction adjacent the screen side of the preform. Such drying or warpage sometimes tends to disorient the lock flap button to such a degree that the carton will not lock initially, or would be readily opened during handling or transport.

The relatively thin planar section of the prior art lock flap tends to dry more rapidly than the bottom or lid sections.

Utilizing the principle of pre-drying of a relatively thin section of molded pulp, an unusual phenomenon occurs by incorporating three-dimensional rib structures on the planar section. As clearly illustrated in FIG. 9, after a carton preform is deposited on a suction mold, and removed therefrom for the purpose of permitting it to dry, the lock flap 16 will dry first, then the lid section 20, and then the relatively thick bottom section 12 dries last. Referring particularly to the drying action which occurs in the lock flap section 16, the planar base 40 initially dries and becomes substantially set, pulling the pulp fiber of the rib elements 42 together or compressing the same inasmuch as this portion is still damp, although the planar base 40 is dried. The initial drying action of the planar base 40 tends to cause bowing of the lock flap on the screen side. However, when the rib elements 42, which are substantially three-dimensional and solid, dry, they shrink and pull together. When this occurs, the planar base 40, which is already dry, and the drying of the rib elements actually pre-stress the planar base 40 and imposes therein internal tension which tends to flatten the planar base 40 to a degree wherein the previously undesirable warpage or bowing is substantially eliminated.

Further, in addition to maintaining the planar base 40 in a substantially single plane, by disposing the rib elements 42 symmetrical to the lock button 44, the lock button 44 is maintained in a substantially pre-selected position, and thus dimensional requirements of the lock flap are maintained within prescribed limits. Still further, by pre-stressing the planar base 40 by virtue of the drying of the rib elements 42, the lock flap 16 is internally pre stressed to resist mechanical deformation in the normal bending planes of the lock flap to prevent mechanical deformation during opening and closing of the carton.

Referring to the lid section 26, it will be noted that an aperture 72 extends transversely through the forward wall 26 thereof and into the top wall 22. As seen in FIG. 3, and as illustrated by the solid phantom lines, the lock flap 16 is inserted adjacent the inner surface of the top wall 26 of the lid section 20 and the undercut lip or groove 48 will engage over the abutment edge 74 of the aperture 72 in the lid section. The portion 52 immediately below the lock button 44 not only aids in pro-stressing the planar base 40, but also provides an abutment immediately below the groove 48, see FIG. 3, which maintains the forward wall 26 of the carton in a position whereby after the carton is locked in the manner shown in FIG. 3 by phantom lines, the lock button 44 may be readily pushed through the aperture 72 in the forward wall 26 of the lid section to permit ready release of the lid from the lock flap. The bottom section 12 includes a centrally located abutment 15 having a vertically projecting edge 17 adjacent to the hinge structure 14 and engageable by lock flap 16 tending to urge the lock button 44 into locked engagement in the aperture 72 of the wall 26 of the lid sec tion 14; see dotted lines FIG. 3.

Referring to FIGS. 5 and 6, another embodiment of a carton including the novel features previously mentioned, is indicated generally at 100. This carton includes a bottom section 112, having hingedly connected at 114 a lock flap indicated at 116. Hingedly connected at 118 to the rear upper peripheral edge of the bottom section 14 is a lid section 129. The bottom section 112 includes an upper peripheral flange 132 abuttingly engageable by a peripheral flange 134 of the lid section 120. Additionally, the lid section 120 includes a substantially planar top wall 122 and depending forward and rear side walls 126 and 124, respectively, and end walls 128 and 130.

In this embodiment of the invention, the lock flap 116 incorporates thereon reinforcing and prestressing rib elements indicated generally at 142 and extending from a substantially planar base 140. Additionally, the lock flap 116 has formed thereon an abutment or lock element 144 which is the structural and functional equivalent of thte similarly described structure of the embodiment of FIGS. 1 through 4. In this embodiment of the invention, the planar base includes a lock nose or extension portion 147 which projects a greater distance above the lock element 144 than the comparable portion 50 of the embodiment of FIGS. 1 through 4.

The top section 120 has a transverse aperture 172 which extends a greater distance rearwardly into the top wall 22 to form a rear abutment edge 176. The transverse aperture 172 forms in the forward wall 126 a lower lock edge 174 comparable to that previously mentioned.

It will be readily observed that when considering the solid and phantom line views illustrated in FIG. 6 the lock extension 147 will project upwardly and in front of the lock edge 176 of the top wall 172 at the same time that the lock nose 144 extends over the lower abutment or lock edge 174 formed by the aperture 172 which extends through both the forward wall 126 and the top wall 122. Thus, if a forward rolling action is imposed on the top section 120, the lock tongue or extension 147 will resist movement of the top section forwardly with respect to the lock flap 116.

In the absence of the reinforcing and prestressing ribs 142, a double lock comprising the lock nose 144 and the lock tongue 147 is provided.

Referring to FIGS. 7 and 8, a still further embodiment of a carton is indicated generally at 210, this carton comprising a bottom section 212, a hinge connection 214, and a lock flap 216. A top section 220 is hingedly connected at 218 to the rear upper peripheral margin of the bottom section 212. The top section forward wall 226 and top wall 222 have extending therethrough an aperture 272 which includes a relieved or filleted lower corner structure as indicated at 273, and a lower abutment edge 274.

The lock flap 216 includes reinforcing rib and prestressing elements 242 which are integral and project from a substantially planar base 240. Generally speaking, the pie-stressing and reinforcing rib elements 242 are substantially the same as, and the functional equivalent of, those previously described. However, in this embodiment, a reinforcing element 252 is provided, which it has been found relieves the stresses and maintains orientation of the abutment lock or nose element 244 formed integral with the base 240 and projecting laterally therefrom. Additionally, the upper rib elements 254 and 254' include leg portions 255 and 255', respectively, terminating in inwardly extending portions 257, 257, respectively, which terminate at opposite sides of the lock nose or abutment element 244. This structure not only reinforces but prestresses the base 240 immediately adjacent the lock nose 244 to substantially rigidify the lock flap 216 and permit continued use of the carton lock structure without any substantial mechanical deformation during manipulation of the novel carton.

Briefly referring to FIG. 9, to review the novel principles and functional characteristics of the invention, it will be observed that the novel lock flap and cooperating structure is formed by the method of permitting the substantial planar base of the lock flaps of the disclosed embodiments to dry prior to the drying of the reinforcing or pre-stressing rib elements. It will be noted that the direction arrows of FIG. 9 indicate the early drying of the planar base 240, for example. When this drying occurs and accompanying shrinkage also occurs, the relatively compact three dimensional pre-stressing and reinforcing rib elements 242 will attempt to shrink along their length but are maintained in a relatively fixed position by the already pre-shrunk base 240. Thus, as indicated by the dotted direction arrows of FIG. 9, internal pre-stressing results, which tends to pull the lock flap 216 from a bowed condition to a substantially flat condition, internally prestress the base 240.

It is within the purview of the art that the reinforcing rib elements be incorporated on the side of the lock flap opposite that shown, depending on the condition of control one would desire with respect to projecting or locking elements of various cartons.

As previously mentioned, the manner in which the car ton is manipulated is explained in detail in US. Letters Patent #2,888,l83 and further description of the manipulation of the carton parts in order to open or close the carton is believed to be unnecessary.

It will be obvious to those skilled in the art that various changes may be made without departing from the spirit of the invention and therefore the invention is not intended to be limited to what is shown in the drawings and described in the specification, but only as set forth in the appended claims.

What is claimed is:

1. A molded pulp carton including a bottom section having opposed margins, a lid section and a lock flap section hingedly connected to said opposed margins of said bottom section, and cooperating lock means on said lid and lock flap sections, said lock means comprising aperture means on said lid section and lateral abutment means on said lock flap section; the improvement wherein said lock flap section includes pre-stressed fiber portion intermediately of the hinge connection of said lock flap section and said lateral abutment means for resisting tension and bending deformation of said lock flap section when the cooperating lock means is operated and maintaining said lateral abutment means in dimensionally oriented relationship to said aperture means, said lock flap comprising a substantially planar base having said pre-stressed fiber portion integrally formed therein, said abutment means projecting out of one surface of said planar base, and said planar base including pre-stressing rib elements projecting out of one surface thereof, said rib elements extending between the hinge connection of said lock flap and terminating adjacent said lateral abut ment means, said rib elements being disposed symmetrical to said abutment means and extending in spaced parallel relationship with respect to each other and in angular relationship with respect to said hinge connection.

2. A molded pulp carton as set forth in claim 1 Wherein said rib elements are disposed in longitudinally spaced parallel relation along said hinge connection, symmetrically with respect to said lateral abutment means and terminate adjacent said hinge connection of the lock flap and at said abutment means.

3. A molded pulp carton as set forth in claim 2 wherein certain of said rib elements terminate in parallel foot portions.

4. A molded pulp carton as set forth in claim 3 wherein an opposed pair of said structural elements include terminal portions integrated at opposite ends with said lateral abutment means.

5. A one-piece carton including a bottom section having opposed upper side margins, a lid section including a substantial planar top and depending opposed side wall portions and including lower margins juxtapositionable on the upper side margins of said bottom section, said top section being hingedly connected to one opposed upper side margin of said bottom section, a lock flap hingedly connected to another opposed upper side margin of said bottom section opposite that to which said lid section is connected and normally biased forwardly from said bottom section, said lid and lock flap including cooperating lock means detachably connecting said lid section in juxtaposed relation on the upper margin of said bottom section with said lock flap juxtaposed on the inner surface of the forward side Wall portion of said lid section, the improvement comprising a lateral lock-abutment projecting intermediately from one side of said lock flap, said lock flap including a lock-extension extending above said lockabutment, said lid including an aperture portion extending through said planar top and the forward side wall portion adjacent the juncture thereof, said aperture portion including an upper edge abuttingly engageable with said lock-extension and a lower edge engageable beneath said lock-abutment.

6. In a carton including a bottom section having an upper peripheral portion, and a lock flap lid section hingedly connected on parallel hinge axes at opposite sides of said bottom section and resiliently urged toward planar relation with respect to a plane passing through said upper peripheral portion of said bottom section, the improvement comprising locking means including cooperating portions on said lid and lock flap sections, said lid section including an intersecting top and forward wall, an aperture portion extending through the intersection of said top and forward walls and forming abutment edges in the plane of said top wall and said forward wall, said lock flap section including an intermediate abutment projecting from one side thereof and removably received in said aperture portion and engageable over the abutment edge in said forward wall, said lock flap including a lock extension in the general plane thereof disposed above and behind said intermediate abutment for engaging in front of the abutment edge in said top wall.

7. In a carton as set forth in claim 6 wherein said lock flap includes a pre-stressed fiber portion beneath said intermediate abutment for stabilizing said lock flap against mechanical deformation.

8. In a carton as set forth in claim 7 wherein said lock flap section comprises a substantially planar base from which said intermediate abutment projects, and structural ribs integral with said planar base, said planar base being pre-shrunk prior to said structural rib elements and being pre-stressed thereby.

References Cited in the file of this patent UNITED STATES PATENTS 1,845,970 Katz Feb. 16, 1932 2,348,725 Chaplin May 16, 1944 2,375,993 Hulbert May 15, 1945 2,838,226 Hartmann June 10, 1958 2,888,183 Reifers May 26, 1959

Claims (1)

1. A MOLDED PULP CARTON INCLUDING A BOTTOM SECTION HAVING OPPOSED MARGINS, A LID SECTION AND A LOCK FLAP SECTION HINGEDLY CONNECTED TO SAID OPPOSED MARGINS OF SAID BOTTOM SECTION, AND COOPERATING LOCK MEANS ON SAID LID AND LOCK FLAP SECTIONS, SAID LOCK MEANS COMPRISING APERTURE MEANS ON SAID LID SECTION AND LATERAL ABUTMENT MEANS ON SAID LOCK FLAP SECTION; THE IMPROVEMENT WHEREIN SAID LOCK FLAP SECTION INCLUDES PRE-STRESSED FIBER PORTION INTERMEDIATELY OF THE HINGE CONNECTION OF SAID LOCK FLAP SECTION AND SAID LATERAL ABUTMENT MEANS FOR RESISTING TENSION AND BENDING DEFORMATION OF SAID LOCK FLAP SECTION WHEN THE COOPERATING LOCK MEANS IS OPERATED AND MAINTAINING SAID LATERAL ABUTMENT MEANS IN DIMENSIONALLY ORIENTED RELATIONSHIP TO SAID APERTURE MEANS, SAID LOCK FLAP COMPRISING A SUBSTANTIALLY PLANAR BASE HAVING SAID PRE-STRESSED FIBER PORTION INTEGRALLY FORMED THEREIN, SAID ABUTMENT MEANS PROJECTING OUT OF ONE SURFACE OF SAID PLANAR BASE, AND SAID PLANAR BASE INCLUDING PRE-STRESSING RIB ELEMENTS PROJECTING OUT OF ONE SURFACE THEREOF, SAID RIB ELEMENTS EXTENDING BETWEEN THE HINGE CONNECTION OF SAID LOCK FLAP AND TERMINATING ADJACENT SAID LATERAL ABUTMENT MEANS, SAID RIB ELEMENTS BEING DISPOSED SYMMETRICAL TO SAID ABUTMENT MEANS AND EXTENDING IN SPACED PARALLEL RELATIONSHIP WITH RESPECT TO EACH OTHER AND IN ANGULAR RELATIONSHIP WITH RESPECT TO SAID HINGE CONNECTION.

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