US2461539A - Cartridge case - Google Patents

Description

Feb. l5, E949. E. c. FLETCHER CARTRIDGE CASE 3 sheets-sheet 1 Filed March 16, 1945 Feb 15, i949.

E. C. FLETCHER CARTRIDGE CASE 3 Sheets-Sheet 2 Filed March 16, 1945 ml/@mam wfn@ Febo i5; E949. E. c. FLETCHER CARTRIDGE CASE 5 Sheets-Sheet 5 Filed Maro@ 1e, 1945 Ecl-Wma f3. Flche www.

J Figure 16 is a View of one of the strips from f which the cartridge of Fig. l5 is wound.

content being conventional, 'and Well understood,

In the Y the details thereof are not illustrated. head there is set a body 23 its form and external dimensions conforming to those of prior shells, and it may be similarly secured in the head, so

as to function in gun chambers the same as prior f shells. While its ballistic value is intended to be standard, the following disclosure will make ap-r parent the possibility of control by the nature of the structure in the closure.

The body 23 is a simple hollow cylinder or Wall intended to be formed by the Winding of a cdL posite stock wrapper sheet 2t such as shown Figs. 5 6, upon a suitable mandrel to form a long tube from which a number of bodies 23 may be out as indicated by dotted lines across the sheet 2li. Heretoiore the bodies have comprised five or six convolutions or layers of the wrapper and my invention may conform to this practice, or may have fewer turns of the wrapper and so be somewhat reduced in thickness if desired, owing to the superior rigidity of the wall structure produced by my invention. The stock Wrapper includes a base paper sheet 25 (Fig. 5) having. parallel starting and terminal edges 26-26' representing respec tively the parts for the beginning or" the winding of the body and the termination of the outermost convolution of the paper sheet on the tube and body 23. Each of the adjacent edge portions of the base sheet are tapered in thickness to a very thin extreme terminal edge. While the paper of the nished body is intended to be impregnated with a Water proof material and/or a dampproofing, this may be effected at any stage of production suited to the structure hereinafter described. in one form of the base paper .sheet 225 it has been prepared substantially of the same fiber, quality, and shape heretofore used and familiar.

In a wrapper 24|, Fig, 6a, a zone 2i, on the inner face of the paper base sheet 255i stopping parallel to the finishing edge 2B', extending entirely across the sheet transverse to the direction of winding, and having a dimension in the direction of winding slightly greater than the circumferential measurement of the finished tube, is coated with a cementitious material ZS-or instance a bituminous one (an asphalt composition having been used and upon this coating there is laid and pressed to an intimate united relation with the base sheet 25| a sheet of metal foil Eil or the like, the cement 23 being one especially ei iective in. holding upon smooth metal surfaces, so that the foil is securely fastened upon the sheet 25|. A foil of copper, lead, or other metal may be employed, it being a requirement that the metal be free of openings or voids which would permit transpiration of moisture. Lead has been commonly considered most desirable for the use, although aluminum, copper, Vand other metals are thought to be usable advantageously. Over and upon this foil 29 at the face opposite the Cil sheet 25|, and extending over the margin 3B of the sheet Si between the Zone 2l and edge 25', there is a coating' 3| of a material highly adhesive to metal and of high flexibility and high tensile strength and at least moderately ductile, or strainable without fracture. For this material a butyral polyvinyl plastic has been used, a commercial form of which is named Butvar; but it is practicable to use other resinous products of similar qualities, as, for instance, some of those named in the patent to Harmon, No. 2,300,368, applied so as to provide a coating of say, 0.601 inch thickness or more upon the metal, and using those resins which have the greater strengtlis. 1t is possible to also use other of the known plastics either thermoplastic or thermosetting by appropriate procedure, where they have the desired structural strength, and in the oase of thethermosetting forms, certain improvements in structure are possible, as will be explained.

In the sheet 25| there are formed prior to application of the foil and before application of the asphalt also, if desired, a multiplicity of slots 32, in two closely spaced parallel series extending entirely across the sheet, the slots being elongated and arranged end to end, and spaced slightly in each series. The slots of one series are staggered with those in the other series. These slots are arranged within the area covered by the foil 29, close to theV inner transverse edge of the foil 29 that is, parallel tothe terminal edge 2G', but at the side ci the foil furtherest from the terminal edge. These slots serve to expose the underlying foil so that in the Winding of the sheet 25| the edge portion of the foil distant from the terminal edge 255 of the body sheet containing the slots is overlaid by the extreme opposite and outer edge portion of the foil which is next to the terminal edge Za. in the form of sheet in Fig. 6-a, when it is wound into a tube upon a suitable mandrel, and heat and pressure applied to the terminal edge 25', the latter will be secured so as to hold the tube rmly. Before the winding, paraine 33 as in Fig. 9 or other thermo-softening material may be applied While hot to the entire outer face or the sheet 25 and this may be eiected after application of the plastic 3| at the opposite side, so as to avoid weakening the hold of the plastic 3i directly upon the ber stock. Or, the paraihne may be applied after the winding of the tube. After the winding, if the mandrel used is heated, the convolutions of paper will become united in the one case by the parane, as well as the terminal edge portion to of the sheet secured by the In the other case if the paramns is applied after winding, the parafne will unite the paper convoluticns when the tube or body is drawn through the sizing die.

When the nished body is passed thru the sizing die a complete unitmg of the layers or convolutions is effected by permeation of the parafiine, and if accompanied by a proper degree of heating, the thermoplastic is at the same time united intimately with the underlying paper, serving to secure the final convolution (including the ioil) to the next inner layer of paper, and securing the terminal edge of the foil to its inner edge portion by a series of tacks 315 which consist of portions or the coating 3| extending through the slots S2 from the overlapping edge of the foil to the underlapped edge of the foil, flowing to and becoming attached to the latter under the eect of heat and pressure, as will be understood. At

the same time the terminal edge portion 30 of the essences ysheet!becon'xes-attached to the underlying-'1 paper `which liesfover-the foil.

-`-Using-the bodysheet as prepared in accordance with Figs-5 and 6,'the-procedure is substantially the-same-i-producing -a stock wrapper 24. The lzone 27'- over which asphalt' or other cement 'is-applied however, is extended to the termina-l edge TSG-of the sheet' 25, andfoilzZe--of the same `arealas)before-is also extended tothe edge-218'. Slots.'32 are formed throughthe shes-1.125 in the same-relation. to the inner-transverse edge of the foil Vas'beore, so as to overlie the inner edge 4portioniof the foil lapped by the terminal part of the Wrapper lwhen thewinding is completed soV as to .form plastic-tacks Sil between the lapped portions 4ofs-theifoil `inthe processing of the material, as -be'fore described. The thermoplastic 3i (of the samesnature as the coating 3i), covers only the foil. 'The .Winding and other treatments may be the V"same as before described, producing the shell .ofFigs l, 2 and 3.

IIn Figs."7 and 8 a base sheet 252 is used for the body of the wrapper 242 which may be identical 'Withthe sheet 25 in its laying or felting and simple calendering, but instead of having the slots 32 cut therein isv provided With parallel lines 35 `ofiine perforations extending entirely across the sheet, cr otherwise weakened or predisposed to tear-along thev two parallel lines 3 The strip ..3E,.of;paper^ between. these lines 35 may thus be readilyseparated and torn out of the sheet as indicated in Fig. 8 after attachment of the foil `2e as in either Figs. 5-a cr 6, so as to form a slot-3'! extending entirely across the sheet near :andparallel to the inner of the foil. This strip 3S is'nct` removed however, until after manufacturing "and shipment of the wrapper stock sheets to the tube making plantv and until shortly before the Winding of the tubes is carried out, in-ordcr to safeguard the foil against injury due toits fragile nature. The adhesion of the asphalt composition to the paper so superior to its hold upon the foil that theasphalt is entirely removed with the paper, leaving the surface of the foil clear-*and clean. The plastic 3l also serves as a support and protection for the foil 29. and might :be sufhcient in many respects if the strip 35 were not retained, but retention of the strip is thought ldesirable to safeguard the foil against graving or abrasive injury by obiects which might otherwise directlyengage the foil surface through the slot 3l.

In the use of any of the wrappers as described, after completion of the Winding and ring die-compaction. and sizing of the tube. the cutting out of the bodies 23 and assembly of the heads E! thereon,.theymaybe filled and closed by conventional prioripractices or other approved practices found applicable. In the instant'dsclosure I have used, as irl-Fig. 3, a ycap Ml formed of hat paper stock the same as that used the body of the sheet 25, upon-Which foil 2Q is secured by intervening asphalt 28, and `covered by a thermoplastic 3|. Suitable discs of this built-up'sheet are cut and each formed with an up-turned flange di (the foil-and plastic 3! beiner at the top) to Within andagainst the wall of the body 23 and the cup pressed dournagainst the top Wad l2 over the shot charge 43. The upper edge portion of the Wallabody may then by turned in and downward through 180 degrees within close upon the ange 4! and 'with its extremity vpressed tightly-against the dat part of the ca'o'dil to hold thelatter in place. `Bv applying'a resinous'compositionfto. the end edges of the :body 23'before -forming it againstfthe capt raslast idescribdra sealifasatfd is forme'dlbetween theiextremityif the IWall ofthe shell body' 2S'arid-the'capfinsuring a watertight-joint betWeen'the'Cap chaudes/hell 'flfhis-seall'flli` may-beef the samefmaterial as 'the plastic-3 i, if ldesir-ed, or maybe-a-; adhesive compounded VVaccordance with `l-atent'"1No;"32,- 3cG,36S,-=or-' otherwise.

T'It' should-'be understood Athat l the =adhesvei 28 may Ubel compounded -in accordance -with Ilit-he specication of Patent 2,300,368 in relation eto preparation of adhesives; toassure good`V adhesion of i the material i andagooddamp-'prooness,A astre'- quired, #.or corresponding practice V-With other `materials carried out.

If itlisvdesire'd tocontrolballisticyaluesffthe round embodying my inventionWithstandardad uniform propellantv chargeslthis lmay beedone'by varying thecomposition -ff 'the `seal-Gill@andi/'o1' materialSl-of the cap-:til soi-as to 'varyftheretardance of the charge behind the cap"- aridi-top Wad upon firing ofthe-round.

yIf-idesired, also, the', form Vof closureshowniin said prior patent may be utilized shelleoth'er- Wise l embodying my invention,- vor other approved practicesfollowed.

It will be appreciated that Vowing to the nature of. the plasticv material-*33 I, the' formation of-Fthe slot 31 results Yin theinterpositionof -a-fdamiat 34 as Well as a tackor anchorage between lappedportions of i the' foil. -Theeinterruption =f fthe/continuity :of the sheet f-2,f-'25l,2252,prevents*the wickaction or Vapor penetration of fthe fibers-'in the 'paper Ywhich becomes -slowlyfsmanifest when the prior common waxedV shell is subjec-tdto con-tactv with water or exposed to dampness;v and the dam further ystops any communication -of moisture'from the external convolution to inner paper parts of the shell body. The use of the-cap 40 with its foil and sealed prevents the communication of .moisture through the end ofthe shell.

It Will be appreciated that in the production and handling of the tubing-'and loadingv ofthe shells, thesecurely attached material 3| limits excessive local distentionlof the foilvvhich'Would tend to result in cracks; and similarly, due to this adhesion and the moderate ductilityand coherence of the material 3l, when accommodation is required the material 3l distributes the strain so that fracture of plastic or foil does not occur. Adhesion of the foil carries the latter withthe strained parts of the plastic as well as preventing strain of the foil exceeding that of the plastic so that distension is widely and uniformly distributed in the .foil and liability .of its rupture minimized.

In Figs. 4 and 14v there is illustrated a modication of structure in the Wrapper 243 and in the finished shell, wherein the foil 29 is applied to the base sheet 25 in areas stopping short of the boundaries '48 at which the completed tube is to be cut to form' the shell bodies as shown atr'ds, but abuttingthese boundaries in the opposite direction, so that whenwound and cut the foil 25 stops short of theouter or top open end of the body 23 in each shell, as at 5Fl in Fignl, but extends a short distance above the top Wad 42. The adhesive`28 may extend to the full width of the cut for each body-that is, beyond the foil, to the end of the body'23, or may be only under thefoil as in Fig. 4. The slotting of the sheet'24 may be the same as in Figs. 5, 6-a, or 7. When'this shell is closed by the practice described in connection with Fig. .3,.a similar'seal maybe formed- .bythe cap 40 ian'dfendledge of the.-bodyi.23. By

extending the `coating of plastic 3l over that upper part 5| of the inner face of the sheet 54 not covered by the foil, a moisture seal 52 is provided in the inturned part 53 of the shell end.

As has been heretofore appreciated the metal foil not only serves as a moisture insulation and positive hermetic dam (for which the plastic might also serve over a reasonable period), but is permanently effective in that respect. A consideration important in dictating the use of the foil in addition to the plactic is its high eilciency vas a dam for hot gas products and in absorbing heat, which has a material effect in reducing charring and burning of the plastic and the outer convolutions of paper in the body 23. While not sui'licient to act as a complete re proofing, it is found Sucient as a delaying means during the short time elapsing in the propulsion of the shot load and escape of propellant products.

In the use of the cap 4U avoidance of production, on firing of matter tending to obscure Vision is attained, the cap becoming quickly disintegrated and consumed the paper and plastic' being burned and the foil dissipated in such small and inconspicuous particles that they cause no annoyance or obscuration of vision in the direction of firing.

The plastic 3l adds materially to the strength of the shell Wall and therefore the size of the stock sheet 24 may be reduced by the extent of one or more convolutions, or may be made thinner. This Would obviateintroducing an excessive amount of material into the Wall of the body 23 prior to its die pressing to standard radial dimensions.

In Fig. there is illustrated a modification of the closure in which all convolutions of paper in the shell wall inward of the foil 55 and its plastic coating 56 stop short of the open end of the shell, forming a shoulder 5l, the materials being the same as before indicated. n the production of this body 232 the short part 5S may be Wound as a complete stock tube by prior methods, and bodies cut to the shorter length, after which there may be applied a sheet of paper stock 59 of proper size to form a single or more convolutions and having the foil 55 applied and secured'by suitable adhesive 28 throughout or leaving projecting borders corresponding to the starting and finishing edges as before mentioned, as discretion dictates and 'a plastic layer 56 laid on the foil. Or, the short body may be wound individually from a strip {ii} ofthe paper stock of a Width corresponding to the distance between the base of the body and the 'shoulder 5l, across one end f portion of which the sheet 59 may be secured by adhesive 59', the sheet 59 and its foil 55 and plastic projecting beyond one longitudinal edge of the strip i3d as at El Fig. 16. When wound and the body completed by either method an upwardly projecting thin wall part 52 is presented consisting of the edge portion of the sheet 59, foil 55 and plastic 5t, the latter being on the in# ner surface of the Wall. in closing this body a cap 63 consisting of paper sheet material faced the same as in the cap sie of Fig. 3 (with adhesive, foil, and outer plastic 3E) is provided, but preferably having the foil presented inwardly in the shell instead of outward. It is flanged or dished outwardly, as at 64 so that when inserted in the open end of the wall its foil and plastic coated flange face lies against the plastic-coated foil at the inner face of the Wall part 62 and also is coextensive therewith longitudinally of the shell. in the insertion oi' the cap, which may be done by a snug fitting hot mandrel, the cap material and Wall part 62 are heated so that the plastic faces of the cap and Wall are united, connecting the two foil pieces in cap and wall, and a complete hermetic seal effected. The connecting of the foil parts in the cap and wall perfects the hermetic value of the enclosure. A wad 65 may be set in the cap after sealing and the end edge portions of the Wall part 62 and cap flange turned and crimped in against the wad; or the Wad may be inserted in the shell -body below, or on, the shoulder part 5l before placement of the cap.

Conventional or other special closure practices may be followed if desired, and in Figs. 10 to 13 the wall end is cut with sector shaped points 6B adapted to be turned inward to meet and form a flat end Wall 67 upon which a disc 68 is secured, formed of material similar to that in the caps fit and 63. rThe plastic face is applied ilat upon the inturned sector points With application of heat, so that the disc is secured in place and the meeting edges of the points covered and united with a complete seal. By applying adecuate pressure the end of the shell and sector points may be recessed so that the disc sets Within the end of the shell Wall as in Fig. 13.

Alternatively, the flanges of the cap 63 may stop short of the extremity of the Wall, as described in reference to Figs. 3 and 4, and the outer part of the wall turned down Within the flange, this. being obvious from the previous description and illustration. if desired, as conventionally represented in Fig. i7, the stock wrapper 244 for Winding the tubes,- may be made up with a paper base sheet 'f similar to the one 25, except that it is without slots 32 or other opening, on which the foil 69 is laid and cemented, with asphalt or other adhesive I3 either to form one convolution in the wall, or several; and over and upon the foil a second paper sheet 'I9 is placed and secured. In this form the base sheet 254 has the thin zones at its starting and finishing edges 26-26, as Vbefore mentioned. The foil is spaced inward r from the terminal edge 26 and also inward of the adjacent terminal edge 'Il' of the thicker central body portion 'll of the base sheet 254 so as to avoid abrupt thickening of the wrapper. The sheet le may be of a length slightly greater than that of the foil, and is secured by the adhesive 'i3 to the base sheet. This securement may be at the projecting transverse edge portions '.'2 of the sheet lis, only, or may be extended also throughout the area of the foil as at 14. rEhe foil may be attached to -either or both of these sheets by either or respectively a thermoplastic at 'i3 or/and a thermosetting plasticat T4 serving as a stiifener and armor for the foil. One or more convolution areas of the paper on one side of the stock Wrapper may be externally coated with an adhesive (not shown in Fig. 17, but see Fig. 18) ,Y which may be thermoplastic or thermosetting if it is to be at the underside of the wrapper in Winding, and may be a thermosetting resinous plastic if it is to be exposed in the nished shell, although a Wax, as, paranine, may be used to impregnate the sheet as an alternative. Itis an advantage of the structure of Fig. 17 that a very secure inclusion of a foil in the wrapping may be attained Without the use of the expensive plastic such as Butvar, but by mere prior practice in securement of the layers of paper together by paraifine or other impregnation in conjunction With the use of the sizing die. It is believed however that an adhesive at 9 73 or 74 should be used which is of the nature of Butvar, or which has similar adhesiveness, tensile strength, and possibly also the armoring values.

In production oi the shell body with the stock sheet, the part, if any, of the base sheet 254 without foil thereon, next to the starting edge, is wound on a mandrel, as before indicated, and the terminal or finishing edge secured against the underlying convolution of the stock sheet. Either before or after winding the paper of the sheet may be impregnated with Wax or other material which may serve as the adhesive between convolutions of paper over paper. A thermoplastic such as Butvar or other of good tensile strength and adhesiveness is preferred on at least one of the foil, and if desired the slotting of one or both sheets may be carried out in acn cordance with Figs. 5, or 7 and 8, to effect a tack such as that at 94.

In Fig. 18. the stock wrapper 245 may be made up with the base paper sheet 255 (having the same tapered starting and terminal edges 2li- 29' as before), flush with the finishing edge of which a foil sheet i6 is laid and secured throughout as first described by an adhesive i?, which may be asphalt, While upon the exposed face of the foil so secured there is applied. a coat of a thermosetting plastic 'i8 covering the entire areas of the foil, and part of the .paper if desired, to form 3:.

the external surface of the shell. ln the use of this stock sheet, it is wound beginning at the starting edge distant from the foil, but with the foil and nlm arranged so as to be on the outside of the completed tube. l'f desired lthe adhesive 'I1 by which the foil is secured may be a thermoplastic of higher tensile strength than asphalt. The finished wrapping may be smaller th an standard, after which it may be inserted in a standard cylindrical mold tube and expanded against the wall thereof while heated for the necessary curing period, either before or after cutting of the bodies and assembly on the heads 2l. As in Fig. 19, the shell body produced has the metal foil showing under the plastic 78 which serves as a protection for the foil and affords a hard face to vfit the gun chamber without sticking when the latter becomes hot. For this use there are available phenol -aldehydes among which are Bakelite. Those available may be made harder i by reaction with glycerol. Others may be found in glycerol-phthalie anhydride, as Glyptal, Rezyl, Teglac. The slow burning quality of certain of these compounds is a valuable attribute.

Having disclosed the invention in its best emi bodiment known to me, but as a purely exemplary measure, and with the understanding that various changes in `the construction and arrangement of parts, substitution of materials and equivalents mechanical and otherwise, may be made Without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. An inclosure comprising a body sheet including a base ber sheet wound upon itself in a plurality of convolutions to form a tubular lamn inated member, a metal sheet forming part of the body sheet included in a terminal portion and extending over more than one convolution of said body sheet to provide an overlapping edge portion, a 'thin lm of adhesive material between said metal sheet and said fiber sheet, said fiber sheet having a slotted region extending axially across the tubular member in the part underlying the metal sheet at said overlapping portion ofthe latter, and a normally solid elastic plastic highly adhesive lto said metal sheet land of high tensile strength united with the metal sheet on the .other side thereof from said adhesive film and united with at least one convolution of the hase ber sheet and including the slotted part thereof, whereby the outer edge portion of the metal sheet and its inner lapped part are secured directlyT together by said plastic through said slotted part.

The structure of claim i in which said metal sheet stops short of the top edge of said fiber sheet forming an outer end portion on said wall beyond the metal sheet, a closing disc fitted Within and against the wall inwardly of the adjacent encircling edge of the metal sheet, the top edge of the body sheet above the metal sheet being recurved through degrees flat against lthe .subjacent wall part beyond the disc and with its extreme edge in bearing upon said disc.

3. The structure of claim 1 in which said metal sheet stops short of the 'top edge of said fiber sheet forming an outer end portion on said Wall beyond the metal sheet, a closing disc tted within and against the Wall inwardly of the adjacent encircling edge of the metal sheet, the top edge of the body sheet above the metal sheet being recurved through 180 degrees flat beside the subjacent wall part beyond the disc and with its extreme edge bearing upon said disc, said disc having a flanged edge at right angles to the plane of the disc projecting longitudinally of the 'tubular member beside and against the Wall part containing said metal sheet and under said recurved part.

4. The structure of claim 1 in which said rst named plurality of convolutions stop short of the end of the wall of the tubular member and at least said metal sheet and said plastic being extended to form 'the end portion of the wall, a flanged cap including a metal sheet and facing a plastic exteriorly thereon set Within and against said end portion of the Wall, the plastic 0n the flange of the cap being against and united with the said end portion of the Wall.

5. The structure of claim l in which said first named plurality of convolutions stop short of the end of the wall of the tubular member and at least said metal sheet and said plastic being extended to form the end portion of the Wall, a flanged cap including a metal sheet and facing of plastic exteriorly thereon set within and against said end portion of the wall, the plastic on the flange of the cap being against and united with the said end portion of the Wall, said end portion of the Wall being inturned and crimped permanently before the cap.

EDWARD C. FLETCHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 460,397 Morgan Sept. 29, 1891 1,184,753 Keplinger May 30, 1916 1,340,245 Peck May 18, 1920 1,862,301 Drexler June 7, 1932 1,967,844 Schuricht July 24, 1934 2,050,248 Eisen Aug, 11, 1936 2,185,469 MacDonald Jan. 2, 1940 2,318,184 Rojas May 4, 1943 2,346,135 Kress Apr. 1l, 1944 2,359,250 Schmied Sept. 26, 1944 2,408,189 Baker Sept. 24, 1946

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