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United States Patent 3,730,576
Schurman May 1, 1973



A plastic container having a body and a cover and provided with a detachable latch for locking the cover to the body in a closed position. A brace member is provided for reinforcing a shelf formed by a segmental portion of the inner shell of the container body.

Inventors: Schurman; Peter T. (Woodbridge, CT)
Assignee: The Plastic Forming Company, Inc. (Woodbridge, CT)
Appl. No.: 05/112,354
Filed: February 3, 1971

Current U.S. Class: 292/246 ; 206/349; 292/87; 292/DIG.38; 292/DIG.53
Current International Class: B65D 43/16 (20060101); E05c 019/08 ()
Field of Search: 292/DIG.38,DIG.53,DIG.42,246,80,87,88,89,248,250 16/150,DIG.13,158

References Cited

U.S. Patent Documents
3466076 September 1969 Bisbing
1719343 July 1929 Strayer
3490805 January 1970 Pierro et al.
Primary Examiner: Moore; Richard E.


I claim:

1. In a container having mating cover and body parts, a detachable latch member formed of thermoplastic material in a one-piece unitary construction comprising generally parallel mounting and latching bar portions and a pair of generally parallel side leg portions extending therebetween to provide a latching member of generally rectangular configuration, said mounting bar portion having a slot extending therethrough, means on one of said parts for snap-fitted interlocking engagement with said slot of said latch, a locking tab extending from said latching bar portion toward said mounting bar portion, and means on the other of said container parts releasably engaging said locking tab.

2. The combination as set forth in claim 1, wherein said interlocking engagement means comprises an anchor bar projecting outwardly from said one container part, said anchor bar having at least one enlargement and a reduced width neck portion connecting said enlargement to said one container part, said enlargement being received in said slot of said latch in releasably snap through engagement.

3. The combination as set forth in claim 2 wherein said neck portion includes a taper and said slot is defined in part by at least one surface complementary to said tapered neck portion and leading to a shoulder, said enlargement snap-fitting past said complementary surface into locking engagement with said shoulder.

4. The combination as set forth in claim 1, wherein said interlocking engagement means comprises an anchor bar projecting outwardly from said one container part, said anchor bar having a pair of laterally spaced-apart enlargements and a rib extending between said enlargements, and reduced width shanks connecting said enlargements to said one container part.

5. The combination as set forth in claim 4, wherein said shanks have tapered surfaces from one end to the other thereof and said slot is defined in part by surfaces complementary to said tapered surfaces of said shanks.

6. The combination as set forth in claim 1 wherein said means releasably engaging said locking tab comprises a beaded shoulder formed integral with said other container part.

7. The combination as set forth in claim 1 wherein said side leg portions and the outer faces of said mounting and latching bar portions normally lie along a common plane of repose, and wherein said locking tab extends in a second plane offset from and generally parallel to said common plane, said latch member assuming said plane of repose in latching position.

8. The combination set forth in claim 1, wherein said last-named means includes a shouldered enlargement beneath which said locking tab engages in the latched position of said member and abutment means engaged by said mounting bar portion when said member is in said latched position.


This invention relates generally to the container art, and more particularly to a new and improved latch for securing a cover to a container body in closed position.

The blow molding of separate container bodies and covers of a double wall construction is known and is desirable from various points of view. Generally, the cover is hinged along one side thereof to the container body and the opposite side of the cover and also the container body are provided with a latch for locking the cover to the container body in a closed position. These latches often are molded as an integral part of the cover or container body or formed of plastic and bonded or otherwise fixedly secured thereto as an integral part thereof. Such latches are repeatedly flexed and deformed during latching and unlatching and are subjected to recurring stresses with the result that they often tear and are damaged to an extent such that they are no longer suitable for the intended purpose. Because they form an integral part of the cover or container body, the container must be discarded along with the damaged latch.

It is sometimes desirable to cut away only a portion of the inner shell of the double walled container bodies, thereby providing access to the interior of the container body for storage or any other purpose while making use of the remaining portion of the inner shell as an article supporting shelf. This shelf tends to flex and sag downwardly, particularly under the weight of articles placed thereon, and because of its integral connection with the container body sometimes tends to slightly distort the same out of shape, all of which is undesirable.


Accordingly, the primary object of the present invention is to provide a detachable latch construction which is particularly suitable for blow-molded container parts and which can be readily applied to and removed from the selected container part.

Another object of this invention is to provide the foregoing in a latch and an associated mounting part which latter can be conveniently fabricated during a blow-molding operation and which can be readily interlocked in assembled relation.

A further object of the present invention is to provide a bracing member for reinforcing and rigidifying the container body construction which member can be conveniently fabricated during the blow-molding operation.

In one aspect thereof, a plastic container of the present invention is characterized by the provision of a detachable latch member having a configurated slot adapted to receive a similarly configurated anchor bar projecting from one of the container parts for releasable snap through engagement therewith. The latch member has a locking tab releasably engaging behind a shoulder formed integral with the other container part. A brace member extends between the bottom wall of the container body and a segmental portion of the inner shell thereof to support and rigidify the shelf formed thereby.

The foregoing and other objects, advantages and characterizing features of the present invention will become clearly apparent from the ensuing detailed description of an illustrative embodiment there, taken together with the accompanying drawings wherein like reference numerals denote like parts throughout the various views.


FIG. 1 is a top plane view of an illustrative container embodying the present invention, in closed position;

FIG. 2 is a front elevational view of the container of FIG. 1;

FIG. 3 is a top plan view of the container body showing a fragmentary portion of the cover in an open position;

FIG. 4 is a vertical sectional view, on an enlarged scale, taken about on line 4--4 of FIG. 1, showing the means for reinforcing and rigidifying the shelf of the container body;

FIG. 5 is a fragmentary front elevational view, on an enlarged scale, of the latch mounting means and the latch engaging means of this invention;

FIG. 6 is a rear elevational view, on an enlarged scale, of the latch of the present invention;

FIG. 7 is a fragmentary vertical sectional view, on a further enlarged scale, taken about on line 7--7 of FIG. 2; and

FIG. 8 is a similar view taken about on line 8--8 of FIG. 2.


The illustrative container depicted in the accompanying drawings comprises a base or body, generally designated 10, and a lid or cover therefor, generally designated 12. Body 10 is formed of a thermoplastic material blow-molded into the desired shape and having a hollow, double-wall construction formed by an outer shell comprising opposite end walls 14, a front wall 16, a rear wall 18 and a bottom wall 20, and an inner shell 22 initially extending across the upper end of the outer shell in spaced relation thereto except adjacent the edge portions thereof. Inner shell 22 is formed to provide a recessed compartment as indicated at 24 (FIGS. 3 and 4), and can be otherwise compartmented, as desired, for receiving variously shaped articles. After body 10 is removed from the mold, a portion of inner shell 22 is cut-away in the illustrated embodiment to provide an opening 26, leaving a cantilevered segmental portion of inner shell 22 within body 10 to serve as an integral tray or shelf. Opening 26 also provides access to the interior of body 1.

Cover 12 also is formed of thermoplastic material blow-molded into a hollow, double wall construction defined by an outer shell having opposite end walls 28, a rear wall 30, a front wall 32 and a top wall 34, and an inner shell extending across the outer shell in spaced relation thereto except adjacent the edge portions thereof. The cover inner shell has a top wall 36 formed to provide a series of corrugations or ribs 38 extending substantially lengthwise thereof except for a central, forward portion which is recessed as at 40 in spaced relation to a recess 42 formed in top wall 34 of the outer shell. The cover inner shell also has front and rear walls 35, 37 and opposite end walls 39, and is surrounded by a generally horizontal ledge 54 extend to the juncture with the outer shelf. Ledge 54 can be stepped along the front and opposite ends of the cover to fit within the upper end of body 10. Ribs 38 prevent buckling of top wall 34 and also serve to reinforce and rigidify inner shell 36. A suitable handle 44 is pivotally mounted within recess 42 and can be swung out of the way into recess 42 when not in use.

The outer shell of body 10 is formed to provide an outwardly offset band 46, extending horizontally around body 10 adjacent the upper end thereof and the juncture of the outer shell with inner shell 22. The inner shell is formed, adjacent its juncture with the outer shell, to define an arcuate shoulder 48 (FIG. 4) slightly inwardly recessed relative to the upper edge of band 46, and the lower end of shoulder 48 terminates in a generally horizontal ledge 50 which extends about the upper inner edge of body 10.

Cover 12 and body 10 are formed with integral, interfitting hinge pin receiving portions of substantial strength. In the illustrated embodiment, cover 12 is formed along its rear edge adjacent each opposite end thereof with a pair of hinge extensions 52 formed integrally therewith and which depend from ledge portion 54 of cover 12. Extensions 52 are of generally U-shaped transverse section defining channels which are closed at their opposite ends by end walls 56 (FIG. 1) depending from ledge portions 54 and formed integrally with cover 12. Extensions 52 thereby define pockets which normally open upwardly.

Container body 10 is also provided, in the illustrated embodiment, with a series of hinge pin receiving portions adjacent the opposite ends thereof which receive the cover hinge extensions 52 in interfitting relation. The body hinge portions comprise extensions 58 which are like extensions 52 but project rearwardly outwardly from the upper edge of offset band 46 and provide pockets which normally downwardly. Cover hinge extensions 52 and body hinge extensions 58 are formed integral with cover 12 and body 10, respectively, and with hinge pin bearing portions of increased thickness in a blow-molding technique disclosed in detail in copending application Ser. No. 9,529, filed Feb. 9, 1970 and assigned to the same assignee as the instant application, reference being made to said copending application for further details.

When cover 12 and body 10 are assembled, the cover hinge extensions 52 fit between the body hinge extentions 58, as clearly shown in FIGS. 1 and 3. Holes are drilled or otherwise formed through the end walls of each set of hinge extensions 52 and 58 and are disposed in axial alignment for the reception of suitable hinge pins 60. While a simple, ordinary nail can be used as the hinge pin, with the pointed end facilitating passage of the pin through the various aligned openings, it will be appreciated that simple cylindrical stock of any suitable nature can be used, and indeed the pin need not even be cylindrical.

A particular feature of the present invention resides in the latching arrangement provided thereby. In the illustrated embodiment, showing a heavy duty construction, there are a pair of latches, generally designated 62, for releasably locking cover 12 to body 10 in closed position. Each latch 62 (FIGS. 6, 7 and 8) is of a generally rectangular configuration formed as a unitary, one-piece construction and includes a generally horizontal mounting bar portion 64 having a pair of spaced, generally rectangular openings 66 connected together by a central, elongated openings 68 of lesser width or height than openings 66 and forming therewith a continuous slot, generally designated 70, extending through bar portion 64. As shown in FIG. 8, the cross section of each opening 66 is defined in the forward portion thereof by spaced upper and lower horizontal surfaces 72 and 74 forming right angles with vertical surfaces 76 and 78 which terminate in opposed lip portions 80 and 82, respectively, defining a throat construction therebetween. Surfaces 76, 78 provide shoulders for a purpose to be described. A pair of opposed inclined surfaces 84 and 86 extend from lip portions 80 and 82 rearwardly in a diverging relation to the rear wall of bar portion 64.

In order to detachably secure latches 62 on cover 12, the latter is provided with a pair of latch receiving extensions 88 formed integral with cover 12 on the front peripheral surface of the outer shell thereof opposite the hinged connections and adjacent ledge portion 54. An extension 88 is provided for each latch, and each extension is provided with a latch anchor bar, generally designated 90, projecting forwardly of cover 12 for interlocking engagement with mounting bar slot 70 of latch 62. Latch anchor bar 90 comprises a pair of spaced, rectangularly shaped locking head formations or enlargements 92 (FIG. 5) connected together by an elongated rib 94 extending therebetween. As shown in FIG. 8, the enlargements 92 are connected to the base of extension 88 by means of reduced width neck portions or shanks 96 having opposed tapered surfaces complementary to surfaces 84 and 86 of the mounting bar portion 64 of latch 62. Head formations 92 are dimensioned to fit within the forward portion of openings 66, with rib 94 fitting within opening 68. The height of head formations 92 exceeds the height of the throat (i.e., the spacing) between lips 80 and 82. However the inherent resiliency of the platic material forming latch 62 and latch anchor bar 90 permits the passage of head formations 92 between lips 80, 82 and into the forward portion of openings 66 with a snap-fit engagement, bar 64 resiliently yielding and deforming to permit snap passage of enlargements 92 through the restricted throats of openings 66. The tapered or inclined surfaces 84 and 86 of bar portion 64 can apart the mounting bar lips 80, 82, thereby facilitating the insertion of anchor bar 90 through slot 70 of mounting bar 64. Once assembled, head formations 92 engage against shoulders 76, 78 to preclude accidental separation of each latch member from its anchor bar.

Mounting bar portion 64 is generally rectangular and relatively thick in cross-section, having a pair of hollowed out portions or cavities 98 extending inwardly of the rear wall thereof adjacent opposite ends of bar portion 64 as shown in FIG. 6. A latching bail of generally U-shape comprises a pair of side legs 100 depending from opposite ends of bar portion 64 and joined at their lower extremities by a horizontal latching bar portion 102 which has a finger tab 104 depending centrally therefrom. Legs 100, bar 102 and tab 104 are relatively thin, compared to the thickness of mounting bar 64, and normally lie in a common plane which includes the front face of mounting bar 64, being substantially coplanar therewith. A generally U-shaped reinforcing bead 106 is formed on the rear side of latch 62 integrally therewith and extends horizontally along latching bar portion 102 and partially upwardly along sidelegs 100. A locking tab 108 extends upwardly from the central portion of bead 106 and projects upwardly above latching bar 102 for snap-fit engagement behind a beaded, latching shoulder 110 provided on the container body as will be described. The front face of tab 108 is substantially flush with the plane containing the rear face of legs 100.

The outwardly offset band 46 is discontinuous adjacent the latches, having laterally spaced end walls 112 (FIGS. 2 and 5) and a box-like enlargement 116 positioned centrally therebetween and joined thereto by generally horizontal abutments 114 (FIG. 5). Each enlargement 116 comprises a front wall 118 (FIG. 8) terminating at its lower end in a bottom wall 120 extending to the upper portion of front wall 16. Latching shoulder 110 is disposed beneath bottom wall 120 adjacent the forward end thereof. A pair of opposite end walls 123 complete the latching enlargement on body 10, which enlargement and abutments are blow-molded with and as an integral part of body 10.

Latch members 62 are readily snap-fitted in assembled relation on their respective anchor bars 90, as previously described. With the various parts assembled as shown in FIGS. 4, 7 and 8, it will be seen that locking tab 108 engages behind latching shoulder 110, securely locking cover 12 to body 10 in closed position. Any force tending to move cover 12 upwardly, away from body 10 is effectively resisted by engagement of locking tab 108 against bottom wall 120 and the direction of such force is such that it will not separate latch member 62 from its anchor bar 90.

It is a feature of this invention that when latch members 62 are in latched position, with tab 108 engaged behind shoulder 110, the latching bail parts 100, 102 lie in their natural plane of repose, whereby they are not under any stress except within that plane. The rear face of shoulder 110 and the rear face of the latching bail are coplanar or substantially so in the latched condition. Locking tab 108 is snapped over latching shoulder 110 by flexing members 100, both to release and to latch the container cover 12. The latch is flexed and bent only upon attachment to latch anchor bar 90 and thereafter only during opening and closing of cover 12, and is not otherwise stressed out of its plane of repose.

As a result, latch member 62 is assured a relatively long useful life, assuming normal use thereof. While latch 62 is formed of a suitable tear resistant material, such as polyethylene or polypropylene having a long flex life, for example, a significant advantage residing in the latch of this invention is that in the event of excessive wear or damage thereto, it can be readily removed and replaced by another latch member without having to discard the entire cover. Both the latch and the latch engaging shoulder are molded parts, the former being injection molded whereby the dimensions thereof can be easily controlled through proper mold design, and forming the latch as a separate member permits it to be made from a different material and, if desired, in a different color than either cover 12 or body 10.

It also is a feature of this invention that when latch member 62 is engaged in latched position, the under surface of latch mounting bar 64 seats firmly against the upper surface of abutment 114 on opposite sides of enlargement 116 and in vertical alinement with latching bail legs 100. This assures better control over the latching dimension which now is determined by the accurately molded latch member 62 and by the base casting used in molding body 10. Legs 100 rest against and are supported by the front faces of abutments 114 which are coplanar with the rear faces of legs 100, when member 62 is in latched position. With this arrangement, the latching dimension is controlled by direct engagement of the latch against the body (i.e., bar 64 against abutment 114) instead of relying upon proper fitting of the cover in its closed position. In other words, the closed position of the cover now is determined by the latch.

While a pair of latches are utilized in the specific container illustrated in the drawings, it should be understood that only one or any number of latches 62 may be employed, as desired and that latch 62 is in no manner intended to be limited in use with the specific container described and illustrated, but has utility in a wide variety of applications wherein it is desired to releasably latch one part to another.

Another significant feature of this invention is the provision of a removable, reinforcing, brace member, generally designated 122 (FIG. 4), for reinforcing and adding rigidity to the cantilevered inner shell 22 of body 10. Brace member 122 comprises a frame having a pair of side legs 124 joined at their upper extremities by an extension 126 extending therebetween. A wedge shaped embossment 128 projects laterally outwardly from the frame and comprises a pair of right angularly related walls 130 and 132 and a pair of inwardly converging side walls 133. Wall 130 extends from wall 132 to the lower end of the frame forming an acute angle therewith and is provided with a plurality of longitudinal ribs 134 for adding strength and rigidity to brace member 122.

In the formation of body 10, an inverted U-shaped recess or well 136 is formed in the outer shell of body 10 approximately midway between the ends thereof by rear wall 18 and a bead or ridge 138 of U-shaped configuration formed in bottom wall 20 immediately adjacent rear wall 18. Since a portion of inner shell 22 is severed and removed after the formation thereof, the remaining portion tends to flex or bow downwardly toward bottom wall 20, particularly when supporting articles in use. To preclude such deformation and rigidly support shell 22, brace member 122 is inserted in body 10. As shown in FIG. 4, the lower end of brace member 122 is placed in the groove, or well defined by bead 138 and the extension end 126 of brace member 122 is fitted into engagement with a downwardly opening groove 136 formed in the shelf portion of the inner shell between wall 137 of compartment 122 and wall 139 defining one edge of the opening through the inner shell. Thus, a strong, rigid shelf, supported and reinforced by brace member 122, is provided in container body 10 for the storage of various articles.

From the foregoing, it is apparent that the objects of the present invention have been fully accomplished. As a result of this invention an improved latch arrangement using a separately formed, readily detachable and replaceable latch member is provided for locking container parts in a closed position. In the event the latch is damaged to render it useless, it can be easily replaced without having to discard the container part to which it is attached. By the provision of a brace member, the segmental portion of the inner shell remaining, in the container body is adequately reinforced to retain its shape and support weighted articles. The container parts, including the latch and brace members, can be made of any suitable thermoplastic material, such as high density polyethylene, polypropylene, polyvinyl and elastomeric polyolefin, which are given by way of example only.

Latch member 60 preferably is injection molded. Brace member 122 can be injection molded, but preferably is molded simultaneously with the container body and cover by compression forming using thermoplastic material severed from the parison as the mold sections close.

A preferred embodiment of this invention having been disclosed and described in detail, it is to be understood that this has been done by way of illustration only.

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