US3339781A - Hollow wall container - Google Patents

Description

Sept. 5, 1967 P. T. SCHURMAN. ETAL HOLLOW WALL CONTAINER 5 Sheets-Sheet 1 Filed March 22, 1965 INVENTORS PETER T. SCHURMAN BY RAYMOND c. CONFER WQ M ATTORNEYSP 5, 1967 P. T. SCHURMAN ETAL 3,339,781

HOLLOW WALL CONTAINER Filed March 22, 1965 v 5 Sheets-Sheet 3 INVENTORS PETER T. SCHURMAN BY RAYMOND C. CONFER ATTORNEYS Sept. 5, 1967 P. T. SCHURMAN ETAL HOLLOW WALL CONTAINER Filed March 22, 1965 l lllllllll 3 FIG. .9.

5 Sheets-Sheet 3 INVENTORS PETER T. SCHURMAN BY RAYMOND C. CONFER MQ M ATTORNEYSP 5, 1967 P. Tv SCH-URMAN ETAL 3,339,781

HOLLOW WALL CONTAINER Filed March 22, 1965 5 Sheets-Sheet 4 INVENTORS PETER T. SCHURMAN RAYMOND C. CONFER gmzezww ATTORNEYS P. T. SCHURMAN ETAL 3,339,781

HOLLOW WALL Sept. 5, 1967 CONTAINER 5 Sheets-Sheet 5 M, x f

FIG.

INVENTORS PETER I SCHURMAN RAYMOND C CONFER Filed March 22,

ATTORNEYS United States Patent 3,339,781 HOLLOW WALL CONTAINER Peter Taube Schurman, Snyder, and Raymond Carl Confer, Gasport, N.Y., assignors to W. R. Grace & Co., New York, N.Y., a corporation of Connecticut Filed Mar. 22, 1965, Ser. No. 441,811 4 Claims. (Cl. 220-9) The present application is a continuation-in-part of US. application Ser. No. 369,159, filed May 21, 1964; Ser. No. 395,132, filed Sept. 9, 1964 and Ser. No. 395,234, filed Sept. 9, 1964.

This invention relates generally to the container art, and more specifically to a new and useful molded plastic container and method of making the same.

This invention is primarily concerned with molded plastic containers having a body part and a cover part hinged thereto. Heretofore, such containers have been quite flimsy, and the cost structure thereof has not been favorable as compared to containers using steel or other nonplastic material, with the result that such containers have not achieved their full potential.

A primary object of our invention is to provide an economical molded plastic container having hinged body and cover parts, which container is substantially stronger and more rigid than prior art constructions of this general type.

A further object of our invention is to provide an economical rigid molded plastic container which is of onepiece construction.

Another object of our invention is to provide a molded plastic container having hinged body and cover parts, which container incorporates a double-wall construction in at least one of its parts.

A still further object is to provide a molded plastic container which is of one-piece construction and contains double-walls in at least one of its parts.

Still another object of our invention is to provide a molded one-piece plastic container having hinged body and cover parts, at least one of which is of double-wall construction, and a method of making the same, wherein either wall can be changed independently of the other.

A still further object is to provide a molded one-piece plastic container having hinged body and cover parts in which at least one has double-wall construction with the inner wall contoured to hold an object in such a manner so as to prevent lateral movement.

Other objects will become apparent as the description of the invention proceeds.

In one aspect thereof, a container constructed in accordance with our invention is characterized by the provision of mating parts joined by a hinge, the parts and hinge being of thermoplastic material, and at least one of the parts being of hollow, double-wall construction.

In another aspect thereof, a container constructed in accordance with our invention is characterized by the provision of mating parts joined by a hinge integral therewith, at least one of the parts being blow molded and the hinge being compression molded, the parts and binge being of thermoplastic material.

In still another aspect thereof, a container of our invention is characterized by the provision of mating parts of thermoplastic material hinged together, a fastener tongue integral with one of the parts, the tongue projecting beyond the one part and having laterally projecting ears on opposite sides thereof, the other part having an integral flange projecting therefrom along the tongue beyond the juncture thereof with the one part, the side of the flange opposite the tongue having laterally spaced shoulders undercut for snap-fit engagement with the ears when the tongue is rolled over the flange.

One method of making a container of thermoplastic ma-. terial having mating parts joined by a hinge, in accordance with our invention, is characterized in one aspect thereof by the step of blow molding the parts and simultaneously compression molding the hinge.

In general, the plastic material is extruded in tubular form. Thus tubular extrusion is preferably of oblong cross section and complementary mold parts are closed against the relatively flat surfaces of the extruded tube. One mold part has a pair of adjacent cavities which form the exteriors of the two parts of the receptacle and the other mold part is shaped to form the exposed surfaces of the interior walls of the receptacle parts. When the mold parts close they pinch the extrusion walls about the aforesaid cavities to form the meeting edges of the two receptacle parts and a unitary hinge may be molded by complementary mold parts which extend between the two cavities.

This pinching and forming forms two joined envelopes which are then inflated to assume the configurations of the mold cavities of one mold part and the exposed surfaces of the inner walls of the receptacle parts which are formed at the other mold part. In manufacturing one of the receptacle of the present invention, the aforesaid oblong extrusion is formed so that one of its flat wall surfaces is substantially thinner than the other whereby, after blowing, the exterior walls of the receptacle are substantially thicker and more rigid than the interior walls.

In one form of receptacle illustrated and described herein the exterior and interior walls of both body parts are spaced and out of contact with each other at all points excepting where they meet about marginal portions which gefine the meeting edges of the two receptacle body memers.

In a preferred form shown and described herein the receptacle parts are simultaneously molded and are joined by an integral flexible plastic hinge which is formed dur ing the molding operation. However, it is to be understood that, in a broader aspect of the invention, the two receptacle parts may be formed as separate members and connected by other hinge means or by other connecting members. In another form of the present invention as shown heren by way of example, a portion of one of the interior walls is cut away, leaving the remainder to form a permanently covered compartment, in a manner and for purposes which will be explained more fully later herein.

A further feature of the present invention resides in the provision of an inwardly depressed formation in an extenor wall of one part of the receptacle which provides a pad or platform at the interior thereof which supports one side of an object in the receptacle, the other side of such object being held resiliently against the pad or platform by the relatively flexible interior wall of the other part of the receptacle.

The foregoing and other objects, advantages and characterizing features of our invention will become clearly apparent from the ensuing detailed description of some 1l lustrative embodiments thereof, considered in conjunctron with the accompanying drawings wherein like reference numerals denote like parts throughout the various views and wherein:

FIG. 1 is a side elevational view of an illustrative container of our invention, in closed position;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a vertical sectional view thereof, taken about on line 4-4 of FIG. 2;

t FIG. 5 is a corresponding view thereof, in open posiion;

FIG. 6 is a sectional view of the body part thereof, taken about on line 6-6 of FIG. 5;

FIG. 7 is a sectional view of the cover part thereof, taken about on line 77 of FIG. 5;

FIG. 8 is an enlarged, fragmentary sectional view through the fastener thereof;

FIG. 9 is a top plan view of another receptacle of the present invention in open condition showing the interior surface thereof;

FIG. 10 is a cross sectional view on the line 10-10 of FIG. 9 but with the parts in closed condition;

FIG. 11 is a top plan view of still another receptacle of the present invention in open condition showing the interior surfaces thereof;

FIG. 12 is a cross sectional view on the line 12-12 of FIG. 11.

Referring now in detail to the illustrative embodiment of our invention depicted in FIGURES 1 to. 8, there is shown a container comprisingmating parts 1 and 2 joined by ahinge 3 integral therewith. Part 1 comprises a relatively deep body part of hollow, double-wall construction formed by an outer shell having opposite end andside walls 4 and abottom wall 5, and an inner shell having opposite end andside walls 6 and a bottom wall 7. Side andend walls 4 of the outer shell are joined to side and endWalls 6 of the inner shell by a peripheral flange in the form of alodge 8 completely encircling the inner shell. Anupstanding rib 9 is formed onlodge 8, for a purpose to be described.

In like manner,part 2 comprises a relatively shallow top cover part of hollow, double-wall construction having an outer shell formed by end and side walls 11 and abottom wall 12, and an inner shell formed by end andside walls 13 and abottom wall 14. The inner and outer side andend walls 13, 11 are joined by a peripheral flange in the form of an inwardlyoffset ledge 15 encircled by askirt 16 and completely encircling the inner shell.

Of course,parts 1 and 2 also can be of the same size, andpart 2 can be larger or deeper than part 1, if desired.

It is one particular feature of our invention that body and coverparts 1 and 2 are molded, integral withhinge 3, in one piece, and in a manner imparting great flex endurance to hinge 3 while providing the hollow, doublewall construction ofparts 1 and 2. This is accomplished, in accordance with our invention, byblow molding parts 1 and 2 andcompression molding hinge 3 in one operation. To this end, the container is molded with the parts positioned as shown in FIG. 5, the handle being added later.

The molten plastic material is extruded in tubular form between mating die parts, not shown, which then are brought together to pinch the plastic tube at its upper and lower ends, whereupon air under pressure is introduced into the closed tube to force it outwardly against the die parts, all in a manner well known in the blow molding art. However, whereas the tube of molten plastic normally is pinched closed only at its ends, in accordance with our invention the tube also is pinched closed between its ends, to define and compression mold thehinge 3.

The mating die parts are arranged so that one die part defines theouter shells 4, and 11, 12 while the other die part defines theinner shells 6, 7 and 13, 14. These portions of the container, together withparts 8, 9, 10, 15 and 16, are formed by blow molding, compressed air being introduced into thecontainer parts 1 and 2 throughneedle openings 26 and 26' respectively, the location of which is' not critical. The coacting die parts, in addition to defining spaced cavities for blow molding the container parts, pinch the plastic tube at the hinge and therebycompression mold hinge 3.

The blow molding apparatus used with our invention is conventional, and therefore not shown, except that the dies are formed to pinch the plastic tube between its ends and therebycompression mold hinge 3, and except that compressed air is injected into two cavities, instead of the usual one. Any thermoplastic material having the requisite flexibility forhinge 3 can be used, high density polyethylene, polypropylene, polyvinyl and elastomeric polyolefin being examples of suitable materials.

Thus, there is provided, in one operation, a one-piece molded container utilizing blow molding to provide hollow, double-wall body and cover parts, 1, 2 while also utilizing compression molding to provide a hinge which exhibits extended flex life. This has many advantages. For example,ledge 8 provides a shelf imparting, in conjunction withinner shell 6, 7, substantial rigidity to body 1. In like manner,ledge 15, together withinner shell 13, 14 imparts substantial rigidity to cover 1. For increased rigidity, the corners of the inner shells can be made to contact the outer shell, and can be joined thereto, as indicated at 27 in FIGS. 4 and 5. Also, the inner and outer shells can be welded at selected points as shown at 28 in FIG. 5. In this way the flimsiness characteristic of conventional, single shell molded plastic containers is avoided.

The hollow, double-wall construction of the container parts also provides a protective cushion for the contents of the container. The shock resistance of such construction affords a degree of protection not available with conventional single shell construction.

Where buoyancy is desired, as in fishing tackle boxes, either body part 1 orcover 2, or both can 'be made fluid tight by sealing the needle holes 26, 26'.

In addition, with the container and method of our invention the interior of the container can be varied independently of its exterior, and vice versa. This is accomplished by changing the appropriate die part, which can be done because of the blow molding ofparts 1 and 2. Indeed, either the interior or the exterior of only one ofparts 1 and 2 can be varied, if desired. All of this can be dpne while still providing the compression moldedhinge 3.

Where it is desired to provide a separate insert, theinner shell 6, 7 of the body part 1 can be either partially or wholly removed, as indicated by the broken line showing thereof in FIG. 4. This can be done by cutting, preferably through side and endWalls 6 in a plane parallel toledge 8. This hides the cut, and also leaves a portion ofwall 6 for added rigidity. In this respect, it will be noted thatledge 8 continues to impart rigidity to the body part, even with the inner shell removed. An inwardly offsetshoulder 10 can be provided, to receive and support an insert, not shown.

If desired, the inner shell ofcover 2 can be removed, preferably in like manner. Of course, where the inner shell is to be removed, it will be joined to the outer shell as shown at 27 and 28.

Hinge 3, being compression molded, has a long flex life, and will withstand repeated opening and closing of the container for as long as the container is used. In closed position, skirt 16 ofcover part 2 rests againstledge 8, in-encircling relation torib 9 which helps maintainparts 1 and 2 aligned when they are closed.

Extending fromcover part 2,opposite hinge 3 and in the plane ofskirt 16, is a fastener tab ortongue 17 terminating at its outer end in anenlarged head 18 havingears 19 projecting laterally beyond the opposite sides oftongue 17.

Body part 1 has aflange 20 projecting laterally outwardly alongtongue 17 to a point betweenfastener head 18 and the juncture oftongue 17 and side wall 11. Undercutshoulders 21 are formed on the side offlange 20opposite tongue 17, and project beyondflange 20 in alignment withears 19.

Whencontainer parts 1 and 2 are brought together, to the closed position shown in FIG. 4, thefastener tongue 17 is rolled over the cam surface offlange 20, andears 19 snap over and beneath undercutshoulders 21, to releasably hold the container closed.Fastener tongue 17, with itshead 18 andcars 19, is compression molded in the same manner and at the same time ashinge 3, and thereby has a long flex life. The flex life oftongue 17 is extended, by the provision offlange 20 which causes the tongue to flex along a line spaced from its juncture with wall 11, instead of at that juncture.

The outer shell of body 1 may be recessed, at its end oppositehinge 3, as indicated at 22, the opposite side walls of the recess being apertured to receivepintles 23 pro jecting laterally from the opposite ends of apail type handle 24. The opposite end of the outer body shell may be molded to provide a pair oftapered feet 25, the outer extremities of which are spaced from wall 4 a distance slightly greater than the projection of hinge 3' fromwalls 11 and 4 when the container is closed.Similar feet 25, or a single foot, may be molded into the outer cover shell. These feet support the closed container in an upright position and prevent the weight of the container and its contents from resting on the hinge.

Flange 20 and undercutshoulders 21 are compression molded in body .part 1, andrecess 22 andfeet 25 and 25' are blow molded therein, at the time body part 1 is formed.

In another embodiment of the present invention, the receptacle or container shown in FIGURES 9 and comprises a pair of box-like complementary body members designated generally 29 and 30 which in the illustrated instance are molded integrally to include relatively thin connectinghinge portion 31. For convenience of reference themember 29 may be considered to be the bottom member and themember 30 the top or cover member.

Thebody member 29, as is clearly shown in FIG. 10, comprises a blown hollow structure which includes a relativelyrigid cutter wall 32 and aninner wall 33 which is substantially thinner thanouter wall 32 and is accordingly substantially more flexible. Thebody member 30 likewise includes a relatively rigidouter wall portion 35 and a thinnerinner wall portion 36 which is substantially more flexible than theouter wall portion 35.

It will be noted by reference to FIG. 10 that in the case of both of thebody members 29 and 30 the blowing of the inner and outer wall portions thereof produces interfitting marginal edge formations designated 37 and 38, respectively, which formations occur generally along lines which define the meeting edges of the respective outer and inner wall portions of the body members.

Receptacles constructed according to the present invention may be designed to receive a variety of articles, the receptacle being arranged particularly to receive specific articles or pieces of equipment or as general carryall receptacles. In the present instance the receptacle, merely by way of example, is designed to receive an electric carving knife which conventionally includes a body member which includes a handle portion and electric motor means contained therein, the knife blade per se being normally separated from the handle portion when the device is not in use.

Referring particularly to FIG. 9, theinner wall 33 of thebottom body member 29 is provided with a pair ofdepressed well formations 39 and 40 which receive portions of the body or holder member of the electric carving knife and theinner wall 36 ofupper body member 30 is provided with adepressed well formation 41 which seats over the opposite side of the body member of the knife, whereby such body member, which is indicated in dot and dash lines at A in FIG. 10 is securely held between the respective well formations of themembers 29 and 30 when the container is closed. Any desired form of clasping or latching means may be provided for holding thereceptacle body members 29 and 30 in relatively closed position, as for instance, the latch means previously described with reference to FIG. 1 to 8.

The knife blades which are separable from the knife holder are adapted to seat inrecesses 42 and 43- inlower body member 29 andelevated surface portions 44 and 45 ofinner wall 36 of upper body member 30' seat against the knife blades when the receptacle is closed to hold them firmly in position. Afurther well portion 46 inlower body member 29 may receive the electrical cord which extends from the knife body member and the numeral 47 designates a relatively shallow recess ininner Wall 36 of theupper body member 30* which in the pres ent instance merely receives labelling indicia.

It will be seen from the foregoing that the knife body member indicated as A is in a sense resiliently suspended between the rigidouter walls 32 and 35 by the relatively more flexibleinner walls 33 and 36 so that a floating mounting for the body member A is provided which is calculated to protect the same against jarring or shock to which the receptacle generally may be subject at times.

In another embodiment of the present invention as shown in FIGURES 11 and 12, the form of container shown herein by way of example comprises a pair of boxlike complementary body members designated generally 48 and 49 which are molded integrally to include a relatively thin connectinghinge portion 50. Thebody member 48, as will be noted particularly from FIG. 2, comprises a blown hollow structure which includes anouter wall portion 51 of such thickness as to be relatively rigid and aninner wall 52 which is substantially thinner thanouter wall portion 51 and is accordingly somewhat flexible.

Thebody member 49 likewise includes a relatively rigidouter wall portion 53 and a relatively thinnerinner wall 54 which is more flexible than the outer wall.Body member 49 is likewise blow molded but in this instance portions of theinner wall 54 are cut away in a manner and for purposes which will presently appear.

As hereinbefore pointed out, the containers or receptacles constructed according to the present invention may be designed to receive a wide variety of articles. For the purpose of illustration, a case for an electrical soldering gun and certain accessories therefor are completely described by way of example.

It will be noted thatinner wall 52 ofbody member 48 lies substantially at the meeting plane of the body members but includes a majordepressed portion 55 to provide an article-receiving recess and afurther depression 56 is formed indepressed portion 55. Theinner wall 52 further includes a pair of raised bead orrail formations 57 and 58.

Referring to theother body member 49,inner wall 54 thereof hascutout portion 59 corresponding roughly in outline with thedepressed portion 55 and has a raisedpad 60 in therigid wall 53 thereof which registers generally withdepression 56 when the receptacle is closed and is formed by depressingrigid wall 53 inwardly.

The remainder ofinner wall 54, that is, the portion which is not cut away to form theopening 59, forms a shelf connected at three sides to therigid portion 53 ofbody member 49.

The shelf portion ofinner wall 18 is formed with elongate recesses of semi-circular cross section as at 61, 62, 63, and 64, acircular recess'or depression 65 and anangular recess 66. The handle portion of a conventional soldering gun lies in thecutout 59 ofwall 54 with its barrel lying inrecess 61 and with one of its side walls lying againstpad 60. When the receptacle is closed thedepressed portion 55 of the otherinner wall 52 engages against the other side of the handle portion of the gun and the proportions are such that the handle of the gun is closely confined and securely held betweenpad 60 and thedepressed portion 55 ofinner wall 52.

The relative flexibility ofwall 52 permits the latter to yield resiliently upon engagement ofdepressed portion 55 against the gun handle. Thepad 60, being offset fromouter wall 53, may likewise contribute to the yieldable gripping of the handle of the gun betweendepressed portion 55 andpad 60. Prior to placing the solder gun handle in the opening orcutout 59 the electrical cord thereof is pushed beneath the shelf formed byinner wall 54.

The usual soldering gun barrel which holds the soldering tip at its outer end lies inrecess 61 when the gun handle is placed as described above. Other sizes or types of barrels or tips are received inrecesses 62, 63, 64 and 66 andrecess 65 is provided to receive a coil or solder wire.

7 When thebody member 48 is closed over thebody member 49 as aforesaid the bead orrail formation 57 walls exert a resilient pressing engagement against the contained parts.

The present container may have a latch means like that previously described with reference to FIGURES 1 to 8. In the present drawing the tab portion of the fastener is designated 67 and the complementary tab receiving notch formation ofbody member 49 is designated 68. Thehandle member 69 may likewise be like that previously described with reference to FIGURES 1 to 8. Facing wall surfaces for receiving thehandle member 69 are formed by arecess formation 70 inouter wall 53 of body member 11.

Accordingly, it is seen that our invention fully accomplishes its intended objects. While we have disclosed and described in detail only a few embodiments thereof, it has been done by way of illustration only, without thought of limitation.

Many other equivalent modifications will be apparent to those skilled in the art from a reading of the foregoing without a departure from the inventive concept.

We claim:

1. An integral one-piece thermoplastic container having mating parts joined by a hinge integral with both of said parts with at least one of said parts being of hollow double-wall construction, a fastener tongue integral with one of said parts, said tongue projecting beyond the said part integral therewith and having laterally projecting ears on opposite sides thereof, the other of said parts having an integral flange projecting therefrom along said tongue beyond the juncture thereof with said one part, the side of said flange opposite said tongue having laterally spaced shoulders undercut for snap-fit engagement with said ears when said tongue is rolled over said flange.

2. An integral one-piece thermoplastic container having mating parts joined by a hinge integral with both of said parts, both of said parts being of hollow double-Wall construction with the inner walls being contoured so as to hold an article from lateral displacement therein, a fastener tongue integral with one of said parts, said tongue projecting beyond said one part and having laterally projecting ears on opposite sides thereof, the other of said parts having an integral flange projecting therefrom along tongue beyond juncture thereof with said one part, the side of said flange opposite said tongue having laterally 8 spaced shoulders undercut for snap-fit engagement with said ears when said tongue is rolled over said flange.

3. A container of thermoplastic material having mating parts joined by a hinge integral therewith, a fastener tongue integral with one of said parts, said tongue projecting laterally outwardly beyond said one part and terminating in an enlarged head having ears on opposite sides of said tongue, the other of said parts having a flange integral therewith and projecting laterally therefrom along said tongue to a point between said head and the juncture of said tongue and one part, the side of said flange opposite said tongue having a tongue and head receiving recess and undercut shoulders on opposite sides thereof, the end of said flange being recessed between said shoulders, said ears snap-fitting beneath said shoulders when said tongue is wrapped around said recessed end of said flange.

4. A container having mating parts of thermoplastic material hinged together, fastener tongue integral with one of said parts, said tongue projecting beyond said one part and having laterally projecting ears on opposite sides thereof, the other of said parts having an integral flange projecting therefrom along said tongue beyond the juncture thereof with said one part, the side of said flange opposite said tongue having laterally spaced shoulders under cut for snap fit engagement with said ears when said tongue is rolled over said flange.

References Cited UNITED STATES PATENTS 827,124 7/1906 Speer 220-72 1,217,283 2/1917 Daniel. 2,515,113 7/1950 Chaplin 92-54 2,568,128 9/1951 Morris 264-94 2,666,551 1/1954 Wyman 220-16 X 2,679,244 5/1954 Fucci 206-16 X 2,687,157 8/1954 Cowan 220-31 X 2,735,542 2/ 1956 Shnitzler 220-31 X 2,779,578 1/ 195 7 Corey 263-5 2,781,551 2/ 1957 Richerod 264-94 2,790,547 4/1957 Sutton 206-72 2,811,768 11/1957 Axelson 220-31 X 2,945,582 7/ 1960 Abraham 206-1 3,025,947 3/ 1962 Hammer 220-94 X 3,066,790 12/1962 Armbruster 206-1 3,072,283 1/ 1963 Cross. 3,095,086 6/1963 Berg 20645.19 3,163,287 12/1964 Barnett 206-72 X 3,171,700 3/1965 Parsell 206-4X 3,l92,978 7/ 1965 Horvath -.5 3,206,012 9/1965 Braginetz.

JOSEPH R. LECLAIR, Primary Examiner.

LOUIS G. MANCENE, Examiner. F. T. GARRETT, Assistant Examiner.

Claims (1)

1. AN INTEGRAL ONE-PIECE THERMOPLASTIC CONTAINER HAVING MATING PARTS JOINED BY A HINGE INTEGRAL WITH BOTH OF SAID PARTS WITH AT LEAST ONE OF SAID PARTS BEIGN OF HOLLOW DOUBLE-WALL CONSTRUCTION, A FASTENER TONGUE INTEGRAL WITH ONE OF SAID PARTS, SAID TONGUE PROJECTING BEYOND THE SAID PART INTEGRAL THEREWITH AND HAVING LATERALLY PROJECTING EARS ON OPPOSITE SIDES THEREOF, THE OTHER OF SAID PARTS HAVING AN INTEGRAL FLANGE PROJECTING THEREFROM ALONG SAID TONGUE BEYOND THE JUNCTURE THEREOF WITH SAID ONE PART, THE SIDE OF SAID FLANGE OPPOSITE SAID TONGUE HAVING LATERALLY SPACED SHOULDERS UNDERCUT FOR SNAP-FIT ENGAGEMENT WITH SAID EARS WHEN SAID TONGUE IS ROLLED OVER SAID FLANGE.

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