USRE25113E - Sterilizable and sterilized hypodermic syringe assemblies - Google Patents

Description

STERILIZABLE AND STERILIZED HYPODERMIC SYRINGE ASSEMBLIES Original Filed Feb. 26, 1958 Jan. 9, 1962 E. H. wlLBURN 4 Sheets-ShenI 1 ILII Ll III nl tn 1 4 Sheets-Sheet 2 v E H WILBURN STERILIZABLE AND STERIILIZED HYPODERMIC 'SYRINGE ASSEMBLIES Original Filed Feb. 26, 1958 i Jan. 9, 1962 Jan- 9, 1962 E. H. wxLBURN Re. 25,113

STERILIZABLE AND STERILIZED HYPODERMIC SYRINGE ASSEMBLIES original Filed Feb. 26, 195e 4 sheets-sheet s STERILIZABLE AND STERILIZED HYPODERMIC SYRINGE AssEMBLIEs 4 Sheets-Sheet 4 E. H. WILBURN Jan. 9, 1962 Original Filed Feb. 26, 1958 United States Patent O 25,113 STERILIZABLE AND STERILIZED HYPODERMIC SYRINGE ASSEMBLIES Edgar H. Wilburn, Rutherford, NJ., assignor to Johnson & Johnson, New Brunswick, NJ., a corporation of New Jersey Original No. 2,860,635, dated Nov. 18, 1958, Ser. No. 720,804, Feb. 26, 1958. Application for reissue Oct. 31, 1960, Ser. No. 66,381

23 Claims. (C1. 12S- 218) Matter enclosed in heavy brackets appears in the original patent but forms no part of this reissue specilication; matter printed in italics indicates the additions made by reissue.

The present invention relates to hypodermic Syringe devices for injecting parenteral liquid medicaments and, more particularly, to the types intended to be loaded by the operators just prior to injective use although not limited to the latter; and the present application is in part a continuation of my pen-ding applications Serial No. 520,409 tiled July 7, 1955, and Serial No. 647,312 led March 20, 1957, now abandoned.

A general object of the present invention is to provide such devices wherein the parts may be readily manipulated or assembled together in relative positions permitting thorough sterilization of all parts intended to contact parenteral liquids with which they are to be loaded for injective use in the patients body, `and so that internally they or parts thereof will after such sterilization be protectively isolated from airborne bacteria or closed off in a manner for eticient maintenance of such sterilized condition through subsequent handling preceding loading, such as that which may attend storage and distribution to the ultimate users.

A more specific object of the invention is to provide in such syringe assemblies protective closure means associated with chamber-providing barrel structure which under one condition provides thereat an open sterilizing iluid ow passage leading from the surrounding atmosphere directly to the space within such cap means for flow through `to and from the latter of sterilizing iluid or gaseous medium, heated if desired, to or from the liquid housing chamber of the barrel structure and which under another condition effectively blocks ilow through such passage of airborne bacteria for maintaining eliciently a Re. 25,113 Reissued Jan. 9, 1962 ICC for hypodermic use sterile condition of the interior of the assembly and parts thereof which may have been attained by heat radiation and/or conduction after the parts were brought together in a manner to form the closed assembly. A still further object of the invention is -to provide such a hypodermic syringe device featuring injective needle means permanently carried by the front end of barrel structure with the latter titted with parenteral liquidexpelling piston means, the injective needle means being effectively covered by removable cap means etleiently isolating it from airborne bacteria with the piston means providing valving and protective hood means together permitting ready and effective internal sterilization and maintenance of internal sterile conditions until loaded for injective use.

Another object of the present invention is to provide in such assemblies manipulative piston meanseach of which includes hood structure which provides at the back end of the barrel structure a valving `device which in a, retracted position is in valve open position to permit ready through flow of sterilizing fluid while remaining protectively telescoped with the barrel structure, the forward position o-f the piston means providing closure of the valve means under conditions of balanced pressures prevailing inside and outside of the assembly while allowing automatic valving under conditions of unbalancedpressures.

An additional object of the invention is to provide such a hypodermic syringe assembly in which the front end protective cap means has a relatively small, permanently open passage provided with suitable ltering means assuring internal isolation from bacteria in the surrounding sterilized condition while permitting simple conditioning for loading and then injective use.

Another object of the present invention is to provide i-n such assemblies manipulatable back end opening and closing or valving means of a protective nature to employ with isolating head cap means, whereby flow of sterilizing iluid through the entire assemblies and about their internal parts may be readily permitted in an eicient cleansing manner, and which thereafter will allow in a simple manner etiicient closing off of the back end and isolating of the head end from airborne bacteria to retain ythe sterilized condition of the interiors and internal parts thereof.

A further object of the present invention is to provide such syringe assemblies in forms whereby injective needle means thereof are subjected to such sterilizing flow of cleansing fluid and then securely isolated in housing structures of the assemblies effectively to maintain their sterile condition until injective use.

Still another object of the invention is to provide such assemblies in a form in which means securely closes oil or houses syringe front end structure which may include injective needle means, and means effectively closes off the back end of barrel structure with, if desired, piston means housed in the latter, such closed construction and means thereof effectively maintaining until manipulation atmosphere when in mounted needle-covering position.

A still further object of the present invention is the pro- Vision of a structural embodiment of the device which is readily and economically constructed on a mass production basis and which while permitting eicient sterilization and operation thereof allows discard after a single injective use.

Other objects of the invention will in part be-obvious and will in part appear hereinafter. j

The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts, which will be exemplified in the constructions hereinafter set forth, and the scope of the invention will be indicated in the claims. Y

For a fuller understanding of the nature and objects of the invention, reference should be had tothe following detailed description taken in connection with the accompanying drawings, in which:

FIG. l is a axial section of an embodiment of the h'ypodermic syringe of the present invention, illustrating relative initial positions of parts which will permit passage therethrough of sterilizing gaseous medium;

FIG. 2 is an elevational detail, with parts broken away and in section, of the head end of the barre-l and associated back end of the head end protective cap structure of the FIG. l embodiment;

FIG. 3 is a transverse section taken substantially on line 3--3 of FIG. l;

FIG. 4 is a transverse section taken substantially on linev 4 4 of FIG. 1;

FIG. 5 is an end elevational View of the structure shown in FIG. 1 as viewed from the capped head end thereof; FIG. 6 is an axial section of the embodiment illustrated in FIGS. l to 5 incl., showing the relative positions of parts after they have been sterilized and then telescoped together to close ott passages which were provided for passage of sterilizing gases with the parts inthe relative positions sho-wn in FIG. 1; f

FIG. 7 is a perspective view to va smallerfseale of the 3 structure shown in FIG. 6 and with the parts in the same relative positions;

FIG. 8 is an exploded perspective view, with parts broken a'way and omitted, of the structure shown in FIG. 7;

FIG. 9 is a side elevational view, illustrating manipulation of parts of the embodiment of the hypodermic syringe structure illustrated in FIGS. l to 8 incl. to draw into the barrel 'chamber a charge of parenteral liquid;

FIG. 10 is a side elevational view of the syringe structure shown in FIG. 9 but taken in a plane normal to that in which the FIG. .9 structure is viewed;

FIG. 11 is an axial section taken substantially on line 11'L11 of FIG. 10, showing the syringe structure loaded with parenteral liquid and readied for hypodermic injection of contents;

.\FIG. 1.2 is an axial .section of the embodiment of the hypodermic syringe structure shown in FIGS. l to l1 incl., illustrating piston ejection of parenteral liquid contents into a persons vein;

FIG. 13 is a front end elevational view of piston structure similar to that of the embodiment illustrated in FIGS. 1 to 12 incl., proposing certain strengthening of flexible arms of the cap means thereof;

FIG. 14 vis a side elevational View, with parts broken away and in section, of a modied form of barrel and head 'end protective cap structure which may be employed to advantage in the hypodermic syringe structure illustrated in FIGS. l to l2 inclusive;

FIG. 15 is a perspective View of iinger wing structure embodied in the syringe assembly illustrated in FIG. 14;

FIG. 16 is van enlarged a-'xial section with parts broken away of barrel head 'end and associated cap structures of the embodiment of FIG. 14, showing the valved passage for sterilizin'g gases in `open condition;

FIG. 17 is a side elevational view substantially to the scale of FIG. 16, with parts broken away and in section, of the structure shown vin FIGS. 14 and 16, illustrating closure of the valved passage vfor sterilizing gases;

FIG. 18 is a side elevational view, with parts broken away and in section, of a modified form of barrel head end structure, needle mount and protective cap means, illustrating in full lines the relative positions of parts when the valved passage provided thereby is in open condition yand in dot-dash lines the relative positions thereof'when the valved passage is closed;

FIG. 19 is a view similar to FIG. y18, illustrating still another form of hypodermic syringe structure of the present invention with the valved passage open and featuring a resilient guide 'strip which upon withdrawal of the protective cap prevents contamination of the injective tip of an injection needle included in the assembly; Y

FIG. 20 is a plan view of the vprotective resilient guide strip illustrated in FIG. V19 in flat initial form before being doubled back for insertion in the vprotective cap;

FIG. 2l is a lsectional view, with parts broken away, taken substantially online 21-21 of FIG. 19;

FIG. 22 is a view similar to FIG. 19, illustrating manipulation of the cap to close the valved passage;

FIG. 23 is anv axialfsec'tion of a preferred embodiment of the hypodermic syringe assembly of the present invention, villustrating relative positions of the parts thereof when the piston or plunger means is retracted to its rearward or stop position;

FIG. 24 is a front end view of the hypodermic syringe device shown kin FIG. 23;

FIG. v25 yis an axial section of the structure shown in FIGS. 23y and24, illustrating relative positions of parts thereof when the piston or plunger -means is thrust forwardfully to its forwardposition;

FIG. 26 'is' an enlarged sectional detail of the proximal or head end ofthe barrel structure and the distal or back end of the needle protective cap of the device -illustrated in FIGS. .23-25, shown prior to telescopic intertitting mount of the latter to the former; and

FIG. 27 is an enlarged sectional detail of thevdistal or back end of the barrel structure and the distal or back end of the piston or plunger means of the device illusic intertitting mount of the latter to the former. l

Referring to the drawings, in which like numerals identify similar parts throughout, it will be seen that the present invention involves the provision of sterilizable hypodermic syringe assemblies of various types and forms comprising in combination syringe chamber or barrel means which has or is to be provided with means for injecting parenteral liquid medicaments, e.g., cannula means or injective needle devices, means to expel the parenteral liquid contents of the chamber or barrel means, and removable lcapv means which protectively houses parts thereof and isolates portions protectively from airborne bacteria in the surrounding atmosphere or air t0 maintain the sterile condition of parts of the syringe assemblies until such time as injective use thereof is desired. sure means are provided at both ends of barrel structure to isolate the interior thereof with, if desired, lsuitable in jective needle means housed at the front end and preferably piston means reciprocatively llocated in the barrel structure, the parts and interiors thereof having been effectively sterilized with the closure or isolating means assuring maintenance of the sterile condition of parts. If sterilization is to be effected without through now of sterilizing fluid, such as by heat radiation and/or conduction, the sterilizing is accomplished after the construction or assemblyis protectively closed; but if sterilization is to be effected by through iiow of sterilizing Huid the structure of the isolating cap means is such as to .provide open sterilizing fluid tlow passages or ways for effective sterilization ofl parts as they may be temporarily held `together with such passages or ways having associated means ypreventing or blocking flow therethrough into the interior of the assembly, after the latter has been suitably sterilized, of airborne bacteria or air laden with bacteria. Certain embodiments employ the cap means in a manipulative form movable to passage-open position for permitting now thereinto or therethrough of sterilizing l fluid and which may then be simply manipulated to close the valved passages or ways. In some modifications a valved sterilizing-fluid passage or way is provided at the protective cap means andv leads from the atmosphere exterior of the cap and barrel means directly to the space within the cap means so that ysterilizing fluid may now into and out of the latter and about the structure housedy by it via the liquid outletpassage through the barrel head structure which provides the injective outlet for the lparenteral liquid. The terms passage and way lare used herein in the sense of one or more paths of flow lsince part of la ow Vpassage or way may be provided by a single or plurality of grooves, notches, holes, and the like; and the ilow of steriliziug gaseous medium therethrough maybe in either direction as conditions may dictate.

In the embodiment illustrated in FIGS. 1 to- 1:2 inclusive, barrel structure 50 may be suitably Amolded from any suitable material which preferablymay be a plastic of a composition substantially non-contaminable of parenteral liquid to be loaded thereinto and injectively discharged therefrom. For example, barrel 50 may be `molded 'from .polyethylene which is somewhat elastic. when in thin section. Barrel means 50 preferably comv prises a head end structure 51, including ahead cross wall 52 carrying an outwardly-projecting boss/53 through which is fixed the backend 54 of an injective cannula or needle 55 having its -tip 56 'sharpened for facilitating subcutaneous insertion. The barrel head `end structure 5l also includes a Aforwardly-extending cylindrical flange 57 arranged concentric with the needle-anchoring boss 53 to provide therebetween an annular groove 58. As is illustrated in FIGS. V2 and 3, the inner cylindrical wall 59 of the circular Harige 57 is provided with a plurality In various embodiments protective cover or clotrated in FIGS. 23-26, shown prior to complete telescopof longitudinally-extending notches 60-60 which extend only partially of the full depth of the groove 58 to retain a circular bottom sealing zone 6l of the cylindrical inner wall 59. The barrel structure t]r preferably has a cylindrical side wall 62 which defines a cylindrical bore 63 closed off at the front end by head structure cross wall 52 and with which the bore of cannula or needle 55 communicates. Thus, the cannula or needle bore constitutes the liquid outlet passage for the parenteral liquid chamber defined by the cylindrical side wall 62 and the head structure cross wall 52. Near the back end of the barrel structure 50 bore 63 preferably is provided with an internal constriction or circular rib 64 to serve as a plunger means or piston plug stop, as is more fully explained hereinafter. Rearwardly of the stop rib 64 the barrel bore 63 is counterbored at 65 to provide thereby a socket preferably having a diameter somewhat larger than the diameter of the bore 63 and for a purpose to be indicated later. Such counterboring 65 provides the rear zone of the barrel cylindrical wall 62 with a substantially thinner walled zone 66 which, by virtue of being thinner, is somewhat more flexible. Within the rear zone 66 of the barrel wall is provided an outside annular groove 67, preferably located near the rear edge 68 of the barrel in the form of circumambient lateral back end structure defining an open chamber back end, and which may have a plurality of functions, as explained hereinafter.

An elongated thimble-like cap means or capsule structure 69 is provided for housing front end structure, e.g. the needle 55, and preferably has a closed front end 70, a substantially cylindrical side wall 71, and a cylindrical rear end 72 which snugly fits for telescopic sliding action within the cylindrical inner wall 59 of the circular ange S7. The protective cap 69 may be molded from any suitable material, such as plastic, and may be substantially rigid when formed of more brittle plastic material, such as polystyrene, or if desired may have some elasticity if molded from a more elastic plastic material, such as polyethylene. Frictional t retains the cylindrical rear end 72 of the cap 69 within annular ange 57 inV the position illustrated in FIG. l. In such position of cap 69 fluid or gaseous medium may flow to or from the exterior of the cap and barrel structure 50 through the passage or way provided successively by longitudinal notches 60 60, the open portion of annular groove 58 behind the back edge 73 of the rear end of the cap, the space between the boss 53 and the inner wall of the cap, the space 74 within the cap, and the bore of the needle 55. This will be considered the valve open position of the cap 69 in which the valved sterilizing-iluid passage or way at the cap rear end is open.

Plunger means 75 of the syringe assembly of FIGS. 1 to 12 inclusive may include suitable piston structure 76, preferably in the form of an elongated shaft or stern having an externally-threaded head end 77 threadably received or mounted within an internally-threaded socket 78 in the back end of a piston plug 79which may be molded from suitable elastic-material, such as' rubber or the like. Back end or root 80 of piston shaft or stem 76 preferably is made or molded integral with a plugging element 81 which may be frusto-conical in shape, as shown, and of such dimensions as to wedge into the open back end of the barrel counterbore 65 for secure and sealing closure thereof. The plugging element 81 and the piston shaft 76 preferably are housed coaxially within rear cap means 82 which may be molded integral therewith. Preferably the rear cap means 82 is elongated and provided with a substantially cylindrical bore 83 to define an elongated skirt or hood, as shown. Skirted cap means or hood 82 defines with the conical surface of the plugging element 81 a V-shaped annular groove 84 into which the rear edge 68 of the barrel may be wedged for enhancing the sealing of the rear end of the barrel chamber or bore 63. The plunger means or assembly 75 comprising piston shaft 76, plugging element 81 and rear Vcap means 82 may be molded integral from any suitable material, such as rigid, semi-rigid, or somewhat elastic plastic, e.g., polystyrene or polyethylene.

The side walls of the front end or skirt of the rear cap 82vpreferably are provided with a fluid passage or flow way, such as one or more side openings, which may be in the form of a pair of diametrically-opposed notches 85, 85 extending from the front edge 86 longitudinally back an appreciable distance, as is best seen in FIGS. l and 7 to 10 inclusive. Such diametrically-opposed notches 85, 85 define therebetween a pair of diametrically- opposed legs 87, 87, each of which is provided internally near edge 86 with a circular rib segment 88 which snaps into the annular barrel groove 67 in the outward or rearward position of the plunger assembly 75.

In order to facilitate manual grasp and manipulation of the hypodermic syringe device illustrated in FIGS. 1 to l2. inclusive barrel 50 is provided with suitable finger grasps, such as a pair of diametrically-opposed, laterallyextending finger wings 89, 89 which are receivable in the diametrically-opposed notches 85, 85 of the skirt of the rear cap 82 to permit the latter to be pushed completely forward to the barrel chamber zero capacity or fully expelled position, as is best seen in FIG. 7, which incidentally is the position illustrated in FIG. 6, with the piston plug 79 substantially abutted against the head structure cross wall 52.

Various types of index or scale means may be provided cooperatively on the barrel 50 and the rear cap 82- toyguide the amount of load or quantity of parenteral liquid drawn into the barrel bore or chamber 63 by retraction of the plunger assembly 75 and one such form is illustrated in the embodiment of FIGS. 1 to 12 inclusive, a supplemental or alternative form being indicated Vin FIG. l0. Such index or scale means, as there illustrated, may comprise a series of circular ribs 90-90 arranged about the exterior surface of the rear cap 82 and preferably may be formed in the molding of the latter, with each suitably identified with volume indicia, such as 0 cc., 1/2 cc., 1 cc., l1/z cc., and 2 cc. When one of the ribs 90 is brought to substantial alignment With the barrel groove 67 the volume of the barrel chamber 63 is substantially that of the volume mark on the rear cap 82 and this may be readily determined by observation when the rear cap is molded from transparent material, such as clear polystyrene or foggy polyethylene which in relatively thin section can be clearly seen through. In order to facilitate proper alignment of any particular cap rib 90 with barrel groove 67, the inner wallfof the rear cap may be provided with a plurality of pairs of diametn'cally-opposed nibs 91-91, each pair being associated with one of the ribs, as indicated in FIGS. 1, 8 and l0. When any particular cap rib 90 is brought to substantial alignment with barrel groove 67, the pair 'of diametrically-opposed internal nibs 91, 91 on the inner Wall of the cap associated with this rib and lying substantially in the same transverse plane, as shown in FIG. 10, will snap into the barrel groove by virtue of the elasticity of either the barrel material or the cap and nib material, or of both. Such index or scale ribs 90-90 may also serve to facilitate manual gripof the plunger assembly 75.

Such index or scale means comprising plunger cap ribs 90-90 and cooperating barrel groove 67 may be supplemented by other scale or index means, such as that proposed in FIG. 10, o-r such may-be used in substitution for the other. vAs there indicated the scale may comprise suitable indicia or markings -190 imprinted on a side of the barrel 50 with which transverse yfree edge 86 of one of the plunger cap legs 87 is to be successively aligned as an indicator element. Such index or scale means is particularly usefulV if it is desired to avoid problernsl ofjmolding ribs 90-90-onplungercap 82y and/orto form the latter from opaque-material.

The parts of the hypodermic syringe device illustrated in FIGS. l to l2 inclusive preferably will be assembled for sterilization and then subsequent packingand' use in the following manner. The barrel 50,with,its fixed singleended needle 55 will have applied to the head structure 51 thereof a needle-protective cap 69 which, as'wiil be seen from FIG. 1, will be telescoped over the needle withthe edge skirt zone 72 of the capv Slidably received within the cylindrical head llange 57. Such initial telescope, or slidable mount of the skirt zone 72 of the needle-protective cap 69 within the barrel head flange 57 'will be only to a limited degree, as illustrated in FlGS. 1 and 2, so that fluid passage is provided through the plurality of longitudinal grooves 60-60 in the inner wall of the head4 flange, thence into the unlled portion of the annular groove 58 around' behind and past the inner edge 73 of the cap skirt, and then between the spaced inner wall of the` cap skirt zone 72 and the boss 53 to the space 74 withinthe needle-protective cap. This communicates the atmosphere exterior of the barrel' 50 and cap- 69 directly to the space 74 within the cap by a fluid passage' or way at the cap. The space Withinl the cap 69 is in communication with the barrelv chamber or bore 63 by way of the needle bore` 92 which constitutes the liquid outlet passage of the barrel. A suitable piston plug, such as that illu-strated at 79, wil-l be mountedon` the forward end of piston stem or shaft 76, such as by threadedf engagement, andthe piston rear cap- 82 will then be assembled to the rear endr ofthe barrel 50 by snapping the interior rib segments, 88,V -88 of the rear cap legs87, 87 into theV annularbarrel groove 67', as i'llustratedin FIG. 1. Such mount-` ing of the plunger assembly 75, to the rear end of the barrel 50 disposes the piston plug 79 within the counterbore 65 of the barrel bore while providingy space between the inner wall of the latter and the piston plug for free passage of fluid. or gaseous medium, as illustrated in FIG. 1. Thismounting; of the piston assembly 75v tothe rear end ofthe barrel 50 in the rearmost or fully retractedv position, as illustrated inF-iG; 1, leaves appreciable portions; off-the diametrically-opposed cap. notches S5., 85- uncovered by barrel structure for-free passage of il'uid to and/or from the rear end of the latter.

Ar plurality of such hypodermic syringe assemblies, such asthat illustrated in FIG. lk are then suitably loaded into a closable sterilizing tank, After loading of the sterilizing tank it is closed and the air therein and in theL open syringe assemblies. exhausted therefrom with simultaneous supply tothe closed tank of suitable; sterilizingfliquid or gaseous medium, such as formalin, ethylene oxide-or steam. When gaseous mediums other than steam are employed they may be heated, if desired, .AsA a result, the sterilizing fluid or gaseous medium not only llows completely about eachof. the; hypodermic syringe assemblies in the tank-but also through the interiorof each of the syringe assembliesfbyv way of the open valvedf sterilizing-uid: passage at the front needle-.protective cap -69 previously described, through the barrel b ore or chamber 63, about the piston plug 79 and itsl supporting pistony stem 76, and through the plunger assembly cap notches 85, 85. For examplesuch Sterilizing, gaseous medium may flow through the longitudinal notches 60-60 in the inner wall of the barrel head ange 57 into the annular groove 58 of the barrel headV structure 51'across behind, the inner end 73 of the needle-protective capv 69, back between the inner wall of the needle-protective cap skirt zone 72 and theneedleanchoring .boss 53 tothe space 74 within, the needleprotective cap. The s terilizing gaseous medium; may then flow from the space-74 within the needle-protective cap69. via theneedle bore 92 into, they barrel chamber or bore63, from the latter past the constricting` stopv rib 6d through` the clearance orl Space provided between the substantially cylindrical exterior surface of'the piston Plug, 79` and the inner wall of' thecounterbore {i5-intothe spacedefined by the bore 8310i the plunger assemblyrear cap-82, and thence through the diametrically-opposed notches 85, in the skirt of the rear cap-to-tanlr atmos-V phere;

Of course, the direction of tlow of sterilizing gaseous medium may be in the reverse direction or a combination of both directions as-the air in the syringeA assembly of FIG. 1 is Withdrawn from-the stcrilizing tankfor-replacement by the sterilizinggaseous medium.v

the piston assembly 75 of'each forward to its extremeforward closing position and then pushing the needleprotective cap 69 of each back to its rearmostclosingv It will be noted thatposition, as illustrated in FIG.- 6. with the needle-protective-cap` 69 pushed completely-backso that its skirt edge zone 72 is wedged into the bottomof annular groove 58;, a fluid seal' is providedatthe rootofthe boss 53 andthe exterior surface of the edge of the cap is lapped by the uninterrupted cylindrical surfaceof the zone 61Qof the interior wall 59 ofprojectinghead flange 57'. of the barrel is wedgedV into the annular groove 84I between the inner surface 83 of'thepiston cap wall andl the frusto-conical plug l81, securely closingoff the backA end of the barrel chamber 63. A molded cylindricalv borev has slight taper to permitwithdrawal ofthe core and'thus any barrel bore-will be of-slight-ly-lessv diameter atrthe closed endv thenv atthe free edge. For example,` in a working model of the present syringe thebarrel bore may be about 1.375 inches long having a diameter at-then vadjacent the root of the piston stem, However, the wedging of 'the plugging elementV 81 into the counterbore 64 ofv the barrel assures a secure iluid seal thereat with a tendency for the plugging element slightly to spread the back edge 68Y of theV barrel and snugits exterior surface more securely against the surface of cap bore4 83. The sterilized, assembly ofLFIGj; 6' is then packaged for distribution.

In use and operation ofthe assembly of'FIG. 6, the physician or the person who is to administer an injection of parenteralA liquid wil'lwithdraw the needle-protective cap 69 and discard it. He thenjthrusts the needle pointl S6 through the pierceable seal of a suitable multi-'dose` container, indicated in dotted lines at 93 inv FIG. 9and retracts the plunger assembly 75 to a position dictating a capacity of the syringe chamber substantially equivalent to the volume of. the injection to be administered, say- 2 ccs.; eg., where Athe. 2 cc. rib 90v becomes alignedwith the barrel groove 67, and with the internal diametrically-opposed nibs 91, 91, opposite that rib snapping into that groove, or when cap leg edge 86 aligns with- 2 cca mark 190 on the side of the barrel, Suction created on the barrel chamber 63 will cause the parenteral liquid to be drawn, up from the container 93 into the barrel chamber and the syringe device will thus be loa-ded for use, such loaded syringe assembly being .illustrated in FIGS. 10 and l1 with the 2-ccs; body of parenteral'liquid indicated in the latter at 94. The needle tip 56 will then be thrust into avpatients esh, such-as-that-ind-icated at 95 in FIG. l2, andlif the parenteralliquid-'is-off the intravenous type, the usual aspirating precautions for a show of' blood will be taken to assure that the needlebore is in communication with a vein, such asthat indicated at 96 in FIG, 12. The person administering the injection holds the barrel SUahead' of the finger wings It will also be noted that the* backedge 68- i 89, 89 between two fingers and with this thumb applies thrust to the back end 97 of the plunger assembly cap 82 to expel the parenteral liquid 94 from the syringe chamber 63 through the needle bore 92 into the patients vein by piston action or forward travel of the piston plug 79.

When syringe assemblies are successively loaded in such fashion from multi-dose supply containers, such as that illustrated at 93 in FIG. 9, it is a common practice to replace withdrawn parenteral liquid with atmospheric air to avoid creating a partial vacuum or low pressure conditions in the container which would tend to resist effective syringe-loading suction on the parenteral liquid contents of the supply container. This is usually done by retracting lor drawing the piston back to fill the syringe chamber with atmospheric air and then after the needle is thrust through the pierceable seal or closure of the supply container thrusting the piston forward to expel the chamber air' into the supply container. Thereafter, the piston is then again retracted to draw parenteral liquid into the syringe chamber; and the syringe is then injectively used in the above-indicated manner. Such practice of pumping atmospheric air into the supply container frequently causes sutiicient concentration of airborne bacteria eventually to be developed in the supply containers .as to cause mold growth and spoilage of parenteral liquid therein. The assemblies of the present invention may be employed in a manner to avoid any such tendency to cause spoilage and mold growth, while permitting pumping of gaseous medium such as air into the supply containers at the time syringes are to be loaded with parenteral liquid therefrom. For example, after sterilization of the FIG. 1 assembly the piston assembly may be thrust forward until its piston head means or plug 79 passes just bey'ond stop rib 64 to the full line position of FIG. 11, whereby the back end of the barrel bore 63 is eifectively closed in a fluid-tight manner but the syringe chamber contains about 2 ccs. of sterile gaseous medium, maintained entrapped therein by subsequent thrust rearward of the needle-protective front cap 69 to the FIG 6 position. Thus the sterilized and sealed syringe assemblies of the present invention, such as the embodiment of FIGS. l to 12 inclusive, may be distributed to the ultimate operators either in an empty condition, wherein the closed barrel chamber has practically no fluid content with the piston means juxtaposed to the head structure, or in a sterile fluid-containing condition so that sterile gaseous medium in the sealed barrel chamber may be pumped into the multi-dose supply container at the time the barrel chamber is loaded with parenteral liquid.

If it is desirable to mold the piston cap 82 and piston stem 76 as an integral unit from a somewhat elastic plastic, such as polyethylene, it may be found that the diametrically- opposed legs 87, 87 of the piston cap are more exible than that desired to assure that the latter will remain, during handling and sterilizing, securely mounted on the rear end of the barrel 50, such as in the position of FIG. l. The piston cap legs, such as 187, 187 of FIG. 13, may be stilfened to avoid such accidental disengagement, such as by thickening the stock thereof, which may be accomplished by providing longitudinallyextending exterior stiiiening ribs 98, 98, as proposed in FIG. 13. Such expedient of stiiening the piston cap legs 187, 187 may be particularly desirable if the tips 86, 86 of such legs are narrowed or rounded olf to provide camming surfaces for camming engagement of the finger wings 89, 89 in forward thrust of the plunger assembly 75, so as to prevent the linger wings from stopping the piston action before complete expulsion of the chamber contents; and, if desired, such piston cap legs may be extended so that when the plunger assembly is in its fully retracted or rearmost position portions thereof will always remain interdigitated with respect to the finger wings.

As illustrated in FIGS. 14 to 17 incl., the finger wings may be separately mounted to the barrel 150 rather than being molded integral therewith. As illustrated in FIGS. 14 and 15, the linger wings may be provided by a separate piece 98 having an apertured mid-portion 99 provided with a through hole 100 which slidably receives a stepped head section 101 of the barrel 150 to abut against a circular shoulder 101' provided by the barrel stepping for locating the finger wings 189, 189 flanking the mid-section 99 in the desired position along the barrel.

Also as indicated in FIGS. 14 to 17 incl., the valved sterilizing-fluid passage at the front cap means may-be provided in a modified form. As here illustrated, the needle-protective cap 169 may have a cylindrical side wall 171, the skirt edge zone 172 of which is provided with a longitudinally-extending notch 102. The head structure 151 of the barrel 150 may have a forwardlyextending coaxial flange 157 defined by an outer cylindrical inner wall section 159 and an inner frustoconical inner wall section 103 merged therewith. The needle boss 153 may have an exterior frusto-conical surface 104 at its root which defines with the surface 103 a tapered annular groove bottom 158 into which the free edge 173 of the needle-protective cap 169 is to be wedged in the valve closing` position. As illustrated in FIG. 16, in the initial assembly of the parts of the hypodermic syringe device of the FIGS. 14 to 17 inclusive embodiment a relatively short zone ofthe side wall free edge 172 of the needle protective cap 169 is telescoped into the cylindrical section 159 of the inner surface of the head flange 157 for holdingthe parts together temporarily and with a portion of the notch 102 uncovered or open. Thus,`

`the space 74 within the cap 169 communicates directly at the cap with the atmosphere surrounding the syringe assembly through the uncovered portion of notch 102, as indicated in FIG. 16. After the hypodermic syringe assembly of the FIGS. 14 to 17 inclusive embodiment has been suitably sterilized, such as in the manner indicated above, `the needle-protective cap 169 will be pushed forward to wedge its edge zone 172 within the-tapered annular groove bottom 158, as indicated in FIG. 17, thereby securely closing oif in a duid-tight manner the sterilizing-iluid passage provided at the cap by the notch102.

A further embodiment of the invention is illustrated in FIG. 18 and as there shown the head structure 251 of the barrel 250 may be provided with a stepped axiallyextending neck having a tapered tip 106 which may be wedgably telescoped into a tapered socket 107 in hub 108 of a removable needle 155 to communicate the needle bore 192 with neck bore 109 which leads to barrel chamber 163. The needle-protective cap 169 may be similar in structure to that proposed in the FIGS. 14 to 17 inclusive embodiment, having a free edge zone 172 of the skirt or cylindrical side wall 171 provided with notch 102vto serve as a valved sterilizing-fluid passage at the cap. The edge zone 172 of the cap telescopically receives a substantially cylindrical enlargement of the stepped neck 105 and when the cap 169 is in the position illustrated in full lines in FIG. 18 a portion of the notch 102 remains uncovered` to permit tiuid to pass therethrough from the atmosphere surrounding the assembly to the space 74 within the cap. After the assembly is sterilized in a manner such as that indicated above, the cap 169 will then be pushed forward to the dot-dash pov sition indicated at 172 in FIG. 18 so that the notch 102 and fluid passage provided thereby is wholly closed by complete lap of the circular land or enlargement 110 of the neck.

If it is desirable or demanded that all exterior surfaces of neck 106 in FIG. 18 which are to be socketed into and lapped by the internal wall of a needle hub socket, such as 107 of the hub 108, of a removable needle unit, such as 155, be sterilized by sterilizing fluidthis may be readily accomplished by having the needle unit initially loosely disposed or housed within the front protective cover, such as 169. The front protective cover or cap 169 may beY of such length with respect to the length of `the needle 'unit -so that vvvhenthe cap is pushed to its rearmost position forclosing the sterilizing iiuid passage leading to the -exterior thereof, it'will carry with it'rearwardly the needle unit to socket the hub 108 of the latter over the container neck 106 to a jamming secure position. For this purpose, the neck 106, needle unit 155 and its hub 108 may be of such relative dimensions and lengths that in the initial position with the needle tip 4in the vicinity -of the closed outer front end 'of the front protective cap 169, thevery tip of the neck 106 is loosely disposed within the mouth at the back end of the hub socket '107, so as to guide the subsequent telescopic jamming of the neck within the hub socket upon rearward thrust of the front protective cap.

In embodiments of the present invention it may be important to sterilize all surfaces of the cap which may be brought, -even accidentally, into contact with any portion of the needle which is to be inserted into a patients flesh so that there can be no possibility of contaminaytion -of the insertable portion of the needle by the person who is to administer `the injection when he removes the needle protective cap from the sterilized assembly for loading -and subsequent injective use. For example, any zone of the inner wall of the cap, such as that adjacent th'e free edge thereof, 'which may havelapped barrel structure or head structure of the latter during the sterilizing process may not have during the latter become completely sterilized and when the cap is Withdrawn, the'latter may be dragged against the tip of the needle to tend to contaminate it. As proposed in FIGS. r19 to 22 inclusive, such possibility of contamination may be eliminated with assurance by mounting a needle guide means within the needle-protective cap with the guide having its parts, which may drag against the needle during cap Withdrawal, thoroughly sterilized and preventing vcontact between the needle and any portion of the cap 'which may not have become thoroughly sterilized during the sterilizing process. For example, the syringe barrel 350 may have a head structure 351 provided with an external annular groove 111 and with the adjacent surfaces of the head structure being 'substantially cylindrical for sliding lap with cylindrical inner surface 112 of edge Zone 272 of a needle-protective cap 269. The needle-protective cap 269 may have two sets of diametrically-opposed or a plurality of radially-spaced nibs 113- 113 and 114-114 with the former set of nibs being located nearest the free -edge 273 of the cap. When the cap 269 has its cylindrical side Wall 271 telescopically assembled to the barrel 350 vin its initial sterilizing po sition as illustrated vin FIG. '19, the 'set of nibs 113-113 snap into the barrel annular groove 111 securely to hold the 'parts together. In Vsuch position 'a plurality of apertures .11S-115 extending through the side wall 271 near the 'free 'edge of the cap 269 or 'edge zone 272 thereof remain vuncovered Vand open to provide communication directly between the atmosphere `exterior of the barrel and cap and the space 74 within the latter so that sterilizing gaseous medium may ow through ysuch cap side holes, 'the vspace within the cap and the bore of needle t55 'to the barrel chamber 63. `Inthe FIGS. 19 to 22 inclusive embodiment, needle guide means 116 is provided which may be kin the vform of an elongated strip of semi-rigid elastic material, such as a springy strip of semi-rigid plastic, e.g. Vinylite, etc. Such needle guide strip 116 has permit it to be slipped loosely down over the needle 55, and its opposite ends 118, V118 are to be folded b'ack or lapped toward each other, as lindicated partially. in dotdash lines in FIG. 19. 4'Ilre lapped back ends 118, A118 ofthe needle guide strip 116 will lthen be received with-l in the cylindrical side wall '271'ofcap 269 asl it is telescoped forward to lap fof the barrel head 35.1 and .in doing 'so a reverse band, such as that indicated at 119, maybe formed in the medial portion the the `strip adjacent the needle-receptive hole '117.

a'medial needle-receiving aperture 117 to 'In op'erationof the Yembodiment illustrated in FIGS. 19 to .22 inclusive, after the assembly has been sterilized with the cap-269 in an initial valvecpen position relative to the barrel 350, as illustrated in FIG. 19, the cap will be telescoped farther back upon the barrel head structure 351, such as to the valve-closing position illustrated in FIG. 22, until Vthe second 'set of internal nibs 114-114 snap into the barrel head groove 111 to hold the parts in their relative positions of closure of the valved sterilizing fluid passage provided by the iside holes -11'5. This increases Vthe lap by the edge zone 272 ofthe cap relative to the substantially cylindrical barrel head structure 351 to close off the passage holes 115-115 in a 'substantially Huid-tight manner. The sets of nibs .113- 113 and 114-114 do not interfere with such telescopic movement of the cap 269 relative to the barrel head 351 if 'the cap is molded from `material having some elasticity so that the small localized nibs will readily .flat- `ten out when pressed against barrel Vstructure and for this purpose the cap and its nibs may be molded integrally from elastic'plastic, 'such as polyethylene. In telescoping the needle-protective cap 269 from the initial valve-open position .illustrated in FlG. .19 to the valve- 1ciosing position illustrated in FIG. 22, the foresh'ortening ofthe :space 74 within the cap causes some accommodating distortion of the lneedle guide strip .116, such as 4an ex.- 'aggeration of the reverse bend V119 in the mid-portion of the strip adjacent the needle hole `117, -as illustrated .in FlG. 22. v

Assume sterilization of the hypodermic `syringe assenibly of the FIGS. 19 to 22 inclusive embodiment in a manner such as that described above when the parts are Vin their relative positions illustrated in FG. i9 and subsequent closing or the valved 'sterilizing kiluid passage provided by the cap side holes 11S-115 by inward thrust of the cap 269 to the position of FiG. 22 .and distribution of the sterilized assembly to a user. .'[he user, Vin preparing to load the syringe barrel chamber 63 with the lbody of parenteral liquid, will withdraw the cap 269 0K from the barrel head structure`351 and the needle A55. The zone of 'the inner wall of the cap Aree edge 272, 'which lapped the exterior surface of the head structure 351 in the position o-f FIG. 19 during sterilization, perhaps would not be effectively sterilized. rhus, in Withvdrawing the cap 269 from oli of the needlel' the user might accidentally drag such contaminated inner Yzone of the cap against the needle tip 56 in the absence of the needle guide-strip 116. However, with the needle guide strip 116 present in the cap -269 `Withdrawal of the cap permits the reverse bend 119 of the medial portion ofthe strip 116 to relax and reverse to` an arched position similar to that indicated 4in dot-dash lines in FlG. 19, and upon further withdrawal the needle y5S slides out of the central hole 117 olf .the guide strip and is prevented from moving'laterally or lradially in any direction lthus keeping its tip 56 out of contact with the contaminated Zone oi the inner wall of the 'cap skirt.

The embodiment illustrated in FIGS. 23 to 27 incl. is preferred vsince it has proven by Vtests to represent a `highly desirable 'form Vfor marketing the invention. In this embodiment lthe complete assembly, referenced 400, 'includes a barrel structure 450 which may be suitably 4molded .from any suitable material, and `preferably may be a plastic olf a composition.substantially non-contaminable of parenteral liquid to be loaded thereinto and iinjectivelydischarged therefrom. yFor example, barrel 45t) may *be molded from ,polyethylene which is somewhat elastic when in thin section. Barrel vmeans 450 preferably comprises .a proxima-l or head `end structure 451, including a head cross wall 452 .carrying an outwardlyproiecting boss or neck 453 through which is lixed the distal or back end 454 of 4an injective cannula or needle 455 having its tip 456 sharpened for facilitating subcutaneous insertion. The barrel head end structure 451 also includes a lforwardly-extending cylindrical dlange 457, arranged concentric with the needle-anchoring boss 453 to provide therebetween an lannularl groove 458, and terminating in a forward circular edge 459. The back face of cross wall 452 preferably is' concaved, as indicated at 460, and provided with a recess 461 into which needle back end 454 reaches, asA shown in FIGS. 23 and 25. The barrel structure 450 preferably has a cylindrical side wall 462 which denes -a cylindrical bore 463 closed ott at the front end by head structure cross wall 452 and with which the bore of cannula or needle 455 communicates in recess 461. Thus, the cannula or needle bore constitutes the liquid outlet passage for the parenteral liquid chamber defined lby the cylindrical side wall 462 and the head structure cross wall 452. Near the distal or vback end of the barrel structure 450 bore 463 preferably is provided with an internal constriction or circular rib 464 to serve as a plunger or piston plug retraction limiting stop, as is more `fully explained hereinafter. Rearwardly lof the stop rib 464 the barrel bore 463 preferably is flared at 465, as is best seen in FIG. 27, to reduce the barrel wall thickness at the distal end, and counterboring may be employed for this purpose, if desired. Such Haring at 465 of the barrel bore 463 provides the rear zone 466 of the barrel cylindrical wall 462 with a substantially thinner wall which, -by virtue of .being thinner, is somewhat more flexible and elastic. The greatest elasticity of the barrel wall may 'be provided by this means at its distal or rear edge 468 which forms circumambient lateral back end structure defining an open chamber back end.

An elongated thimble-like cap means or capsule structure 469 is provided for housing protectively the needle 455, and preferably'has -a nose or front end 470, a longitudinal side wall 471, and a cylindrical distal or rear end 472 which snugly its or telescopes into the annular groove 458 within the circular ange 457. The protective cap 469 may be molded from any suitable material, such as plastic, and may be substantially rigid when formed of more brittle plastic material, such as polystyrene, or if desired may have some elasticity if molded from a more elastic plastic material, such as polyethylene` Frictional fit retains the cylindrical rear end 472 of the cap 469 within annular flange 457 in the position illustrated in FIGS. 23 `and 25. Preferably, the external diameter of lcap distal end 472 is slightly greater than the internal `diameter ofannular flange 457, as will be seen from FIGS. 23, 25 and 26, and the latter will have suicient elasticity to swell out as shown when the cap distal end is jammed thereinto to assure a fluid-tight seal at that point. As in- ',dicated in FIG. 26, the internal diameter of the distal end l472 of the cap 469 may be approximately equal to the :external diameter of barrel neck or boss 453. Such a .a fluid-tight seal may be assured where the cap 469 is -formed of somewhat elastic material, such as polyethyl- ;ene,with provision of such relative diameters of the inter- -itting telescoped parts, or by making the external diameter of the neck 453 slightly greater than the internal diameter of the cap distal end 472 and the external diameter ofthe latter about equal to the internal diameter of .the annular flange 457. In the latter case, forcing of the cap distal end 472 back over the neck 453 swells out -the former which in turn swells out the annular ange 457 in the telescopic interfitting mount o-f the cap 469 to the barrel head end 451, there to assure the desired fluid-tight seal. The cap 469 may have an annular laterally-extending flange 473 forward of thecylindrical distal end 472 against which the front edge 459 of annular head flange 457`may be jammed in the telescopic intertitting mount of the cap on the barrel head end 451, which may also contribute thereat to the effectiveness of the isolation of the space 474 internally of the cap from airborne bacteria in the surrounding atmosphere. Provision for passage of sterilizing fluid to the interior of the needleprotective cap 469 will be explained later.

Plunger means 475 of the syringe assembly illustrated in FIGS. 23, 25 and 27 may include suitable piston structure 476, preferably in the form of an elongated hollow shaft or stem having an externally-threaded head end 477 threadably received or mounted within an internallythreaded socket 478 in the back end of a piston'plug 479 which may be molded from suitable elastic material, such as rubber or the like. The back or distal end of piston shaft or stem 476 at its root 480 preferably is made or molded integral with an enlarged plugging ele- -ment 481 which may bev substantially cylindrical in shape, as shown, and of such dimensions as to wedge into the ared zone 465 of the open back end of the barrel bore 463 for secure and sealing closure thereof. The plugging element 481 and the piston shaft 476 are housed coaxially within elongated rear cap means or hood 482 which may be molded integral therewith, the hood providing a housing skirt for the piston structure. Preferably the hood 482 is provided with a substantially cylindrical bore 483 which may be only slightly greater in diameter than the outside diameter of barrel wall 462 so as to telescope rather closely about the latter with a relatively narrow annular gap therebetween to minimize possibility of entry of contaminable material therethrough to the open back end of the barrel bore 463. Hood bore 483 defines with the annular land provided by the plugging element 81 an annular groove 484 into which the rear edge 468 of the barrel may be wedged for enhancing the sealing of the rear end of the barrel chamber or bore 463. The plunger means or assembly 475 comprising piston shaft 476, plugging element 481 and rear cap means 482 may oe molded integral from any suitable material, such as rigid, semi-rigid, or somewhat elastic plastic, e.g., polystyrene or polyethylene.

The hood 482 is of such length as to assure at least some telescopic lap of the barrel wall 463 in the kback end zone 466 by its front end 485 when the plunger means is retracted to its stop position illustrated in FIG. 23 and as determined by the internal stop or abutment means, such as rib 464. This will assure minimization of entry of contaminable material to the piston shaft 476 and into the barrel bore 463 in all mounted positions of the piston means 475, as will be emphasized furtherA later. Preferably, the piston shaft 476 carries outside abutment means', such as an annular rib 486, in the vicinity of the base of the externally-threaded head end 477 to abut the internal barrel abutment means or rib 464 upon retraction of the plunger means'475 to determine the stop position of the latter. No difficulty in assembling the plunger means 475 with the barrel 450 is caused by this structure since at least the latter is of elastic material to permit the internal rib 464thereof to be swelled and/or somewhat flattened for allowing the piston rib 486 to be thrust forward therepast in tele scoping the piston shaft initially into the cylindrical barrel wall 463. Structure of the piston plug 479 may be relied upon to serve as such cooperative stop abutment means. For example, the piston plug may conventionally carry a plurality of axially-spaced outside annular ribs 487-487 and the rearward one thereof may be moved back, with retraction of the plunger means 475, to abutment of the internal barrel rib 464 to determine the stop position of the plunger means relative to the barrel 450. Of course, the internal barrel abutment means may be in other forms, such as one or more inwardly-extending projections or nibs, to serve a like purpose.

In order to facilitate manual grasp and manipulation of the hypodermic syringe device 450 is provided with suitable finger grasps, such as a pair of diametricallyopposed, laterally-extending finger wings 489, 489 which are located at points forward of the front end 485 f hood 482-when the plunger means 475 is pushed completely forward tothe barrel chamber zero capacity or fully expelled position, sh'own in FIG. 25, with the shaped manually opened by this plunger retraction.

assemblies are packed in sterile envelopes and until the latter are opened and the syringes manipulated. Hospital trials have shown that such sterilized syringe assemblies meet the aseptical requirementsv of the medical profess1on.

In use and operation of such a sterilized hypodermic syringe assembly, such as that illustrated in FIG. 25, the physican, nurse or. other person who is to administer to a patient an injection of parenteral liquid will remove the syringe from its protective envelope and then retract the piston assembly 475 to the stop position illustrated in FIG. 23, drawing atmospheric air into the barrel chamber 463 via the needle lumen, the space in its protective cap 469, the porous sterilized cotton wad 491 and the inlet hole 499 in the cap nose. The air drawn in through the cap nose hole 490 is filtered through the sterilized cotton `wad 49'1 to free any airborne bacteria therefrom and, simultaneously, the sterile air inthe barrel chamber 463 behind the piston plug 479 is forced back out through the back end valve at the distal end edge 468, which is charge of sterile air from the barrel chamber 463 sweeps away atmospheric air which may have ltered into the space between the inner hood wall 483 and the external surface of the barrel wall 462 Vafter removal of the protective envelope. The operator then removes the protective cap 469 and thrusts the needle tip 456 through the pierceable seal of a suitable multi-dose container carrying the parental liquid and discharges thereinto the air which had been drawn into the barrel chamber 463 by retraction of the plunger yasembly 475, temporarily to develop an elevated pressure therein which will assist in subsequent accurate lling of the `barrel chamber with the parental liquid. The needle tip 456 is then immersed in the body of parenteral liquid and the plunger assembly 475 lretracted tov load the barrel chamber 463 Vwith the desired quantity of the liquid, with the pressure imposed on the liquid by the air which had been forced into the container assuring that the liquid will be trans- .'ferred readily through the needle lumen to the barrel chamber walls by diffusion or actual iow. This is important since, if contaminating bacteria had been so ltransferred toV the internal chamber wall, manipulative withdrawal of the plunger assembly would permit the piston plug, in wiping the contaminated barrel wall, possibly to transfer some of the contaminating bacteria to the chamber space ahead of the piston plug for'subsequent admixture with the parenteral liquid drawn thereinto for hypodermic injection.

An embodiment of the hypodermic syringe assembly, illustrated in FIGS. 23 to 27 inclusive as produced for market, has a barrel chamber capacity of 21/2 ccs. with a diameter of about 0.365 at the stop rib 464 and a length between the latter and the head wall 452 of about 2". The outside diameter o-f the barrel is about 0.450" and the internal diameter of the flared zone 466 at the distal end edge 468 is about 0.375". The hood 482 has an internal diameter at its distal end of about 0.455 and the land 481 there at the root of the piston shaft 476 has an outside diameter of about 0.375. The needle protective cap 469 has an overall length of about 21/2 and an internal diameter at its distal end 472 of about 0.25 with the outside diameter of the barrel neck 453 in the annular groove-458 preferably being equal to this internalcap diameter. The outside diameter of the distal end 472 18 of the cap is about 0.343" and the internal diameter of the barrel head flange 457 is about 0.34". The cap passage hole 490 is about 0.016 in diameter andthe length of the cotton wad 491 is about 0.25". lt will thus be seen that fluid passages are provided at the proximal end of the assembly, more particularly at the needle protective cap thereof, by the constantly open passage hole 490 and the ltering porous cotton wad 491 backing the same, and at the distal end of the assembly by the valved passage at the distal end edge 468 of the barrel, which is l openable either manuallyor automatically by a pressure differential. Thus the voids within the syringe assembly are isolated from airborne bacteria in the surrounding atmosphere by the isolating filtering passage at the needleprotective front cap or proximal end, and by the valved passage at the distal end, with the front cap securely sealed in a duid-type manner to they barrel head by the This disv.tight telescopic mount thereat while being slidably reremovably fitted to the barrel heads such as is the case of needles having socketed hubs which frictionally relceive tapered outlet necks extending from the barrel heads with the neck bores communicating with the barrel chambers to serve as the outlet passages for the latter. It is obvious that embodiments of the invention may employ plunger means in which thepiston stem and piston head are made integral with each other, beingfmolded in one piece, if desired, from suitable elastic material.

When plastic materials are employed which can Withstand considerable heat without undue ory distortional sofening sterilization of a closable embodiment of the invention may be accomplished by heat radiation and/or conduction with the construction or assembly in closed condition so that after such heat sterilization the closed condition will maintain until use the sterile condition of the sterilized closed assembly. Thus, for example, the assembly of FIGS. l to l2 incl. may be so sterilized by heat when the assembly is in vthe closed condition of FIGS. 6 and 7. In the FIGS. 14 to l7 incl. embodiment such heat sterilization will 'be accomplished with the parts in the relative closed positions of FIG. 17.

Heat sterilization of the'FlG. 18 embodiment may be `effected with the protective cap 169 in the dot-dash position indicated at 172. Since heat sterilization effectively sterilizes lapped surfaces the embodiment of FIGS. 19 to 22 inclusive may be heat sterilized when in the closed FIG. 22 condition, and in such case needle-guiding means, such as strip 116, is not needed since all surfaces of cap 269 are freed from contamination and the interior surfaces remain sterile. The FIGS. 23 to 27 inclusive embodiment will be heat sterilized in the closed condition of FIG. 25.

It will thus be seen that in the embodiment of FIGS. l to l2 inclusive at least the cap 69 is of a structure to provide thereat a front end sterilizing-uid passage in that the cap skirt zone 72 has an outer cylindrical surface, slidably lapped against the inner wall of axial head flange 57 defining cap-receiving annular groove 58, which is radially-spaced from ange wall portions at longitudinal grooves 60--60 in the axial flange, and an inner circular edge 73 axially-spaced outward of the inner ends of these longitudinal grooves in the outward. position of the cap shown in FIG. 1. Actually this front end flow passage is provided by the cooperative shaping of the cap skirt zone 72 and head flange 57 which is kdependent for provision at least upon the structurevof the cap. In the FIGS. 14 to 17 inclusive embodiment at least cap 169 is of a structure for a like purpose, its skirt zone 172 being provided with passage notch 102 the edges :if which together with the outer end of head flange 57 at the locality of this cap notch define the front end `How passage in the valve-open position of FIG. 16. Also, in the FIG.- 18 embodiment this obtains since the edges f cap notch 102 andthe outer end of the cylindrical portion or enlargement 110 of stepped barrel neck 105 :ogether denneithe front end flow passage in the full line valve-open position of FIG. 18. In the FIGS. 19 to 22 inclusive-embodiment the front end ow passage is dened collectively by holes 115--115 in skirt zone 272 3f cap 269 when the latter is in its forward valve-open position of FIG. 19, and thus at least this cap is of a itru'cture providing thereat the front end flow passage. Likewise, in the FIGS. 23 to 27 inclusive embodiment the 2o f among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above constructions Without departing from the scope of the invention, it is intended that hole l490 in the vcap tip 470 provides the front endflow passage,l so that at least` cap 469 is also of a structure to provide the front end now passage.A v W In all embodiments illustrated inthe drawings one fof :he cap and head means has blocking means preventing iow of bacteria-laden air throughl the front end sterilzing-fluid ow passages into the interiors of the sterilized assemblies. It the FIGS. l to 12 embodiment thisblockng meansrare closed valves, each valve being the por- :ion of the terminal marginv of the cap skirt zone 72 which laps against the inner wall of the axial flange S7 inward of the bottom end of leach longitudinal groove S0 in the closed position of FIG. 6. The FIGS. 14 to 1 7 inclusive construction provides this blocking means in :he form of theportion of the head means axial flange' i7 against which the portions of cap skirt zone 172 adacent the passage notch '102 lap to close off this passage :iotch inI the closed position of FIG. 17. In the FIG. 18 :onst'ruction `that portion of the cyliridricalv surface of ie'ck enlargement 110 whichvis V opposed to front vend flow ga'ssagenotch 102 and` I apsagainst flanking portio'n'sof :he inner walljof cap `skirt zone 172 in the'dot-dash :losed position of FIG. 18 Iconstitntes the blocking means for this passage,anc l neck enlargement 1'10 constitutes fart ofhead means 2.51. The FIGS. 19 to 22 inclusive :onstructiondocates the blocking means on the head neans 351 inthe vicinity f the head cross wall 52 as he portions ofthe outside surface of barrel 350 that are apped againstthose portions ofv the inner wall of cap kirt zone 272 which H ank the front end passage holes l-11S in the FIG. 22 clo s'ed`po`s`ition` The cap means 169 of the syringe 'a'ssenibly 40,0 shovvnriri FIGS. 2 3 to 27 nclusive has the blocking means in' the form of 'sterile :otto'n wad 4 91 whi ch is held in the cap tip 470 by in'- er'nal rib 492 behind the front end How passage provided y hole 490, Asoas to prevent flow4 of bacteria-laden tir through this passage into the sterilized interior of the issembly. l.Although gaseousxmedium may flow through lront end o'w passage hole 490 under the `influence of a lifferential iri pressure Aof atmospheres insideand 'outside f the assembly 400 the cotton wad filter 491 prevents ngress of airborne bacteria, `the gaseous carrier of baceria-laden air may go through but the carried bacteria annot andthus flow of bacteria-laden air through the rontend flow passage into the assembly is blocked.

The blocking means for the back end ow passage of he illustrated embodiments is provided as cooperating titer-engaging means of the barrel means and the plunger 11b-assembly (including the plunger stem, the surroundng hood and the distal or back end connection thereof), n the form of a valve structure at theroot of the plunger tem. However, such blocking means may be located lsewhere along the back end flow passage, such as beween the hood and the exterior of the barrel. For exmpe, the barrel wall may carry an external annular .ange asa base on which the finger grasps or wings are iouned, or as a separate element located therebehind,

gainstvvhich` the freefront edge of the hood is jammed fwthwhiehitisintertted Y.

t will thus be seen "that `the"`ob'je`r."t`s Iset forth above,

Aof said barrel means.

all matter contained in the above description or shown in the accompanying drawings shall vbe interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention' herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is: l

1. A closed sterilized hypodermic syringe assembly comprising, in combination; hollow vbarrel means having head means closing off one end thereof and together defining a chamber` for containing parenteral liquid, the back end of said barrel means terminating' inY circumambient structurefdefining an open chamber back end, said head means having a liquid outlet passage communicating with said chamber for injective discharge of liquid contents; removable protective cap means having a back end supported by said head means and isolating the outlet passage from airborne bacteria in the surrounding atmosphere exterior of said barrel and cap means, at least said cap mean being of a structure to provide thereat a frontend sterilizing-lluid flow passage leading from the surrounding atmosphere directly to the space therein While said cap means remains supported by said head means to permit pressure flow of sterilizing fluid into and out of the cap means and about structure housed in said cap means via the liquid outlet passage and vthis sterilizing-fluid passage, one of Asaid cap 'and head means having blockingy means preventing How of bac'-` teria-laden air through the front end sterilizing-fluid o'w passage into the interior of the sterilized assembly; and plunger 'sub-assembly means including piston means slid-- ably mounted in a forward position in said chamber for drawing fluid thereinto upon retraction to a rearward position and expelling uid therefrom upon forward thrust to its forward position, elongated plunger stern means extending through the open back end of said chamber vand carrying saidpist'on means on its front end, andV an elongated hood having an open front end with its back end being closed and carried by the back end of said plunger stem means, said hood being in a forward position and surrounding a major portion of said stern means with an annular space defined therebetween into which the back end of said barrel means is telescoped with a rear portion of said barrel means protectively housed by overlapthereby, said housed barrel portion and said plunger sub-assembly means being relatively shaped to provide therebetween a back end sterilizingtiuid flow passage leading from surrounding atmosphere at the front end of said hood between the latter and said housed barrel portion to the open back end of the latter for communication to said chamber when said plunger sub-assembly means'is retracted to a rearward position with maintenance of connection thereof to said barrel means, said piston means in such rearward position permitting pressure owtherepa'st of sterilizing fluid into and out of said chamber, said plunger sub-assembly in its forward position and said barrel means having interengaging means serving as blocking means cooperatively closing off the back end ow passageto prevent ow therethrough 'of bacteria-laden air from surrounding atmosphere into the sterilized assembly.

2. The sterilized hypodermic syringe assembly as defined in claim l characterized by the blocking means forthe back end flow passage being in the form of valvev means having cooperating interengaged elements at the back end of said plunger stem means andthe back end 3. The 'st/eiliied "Iiyp'odermic lsy'riilge assembly as defined in claim 2 characterized by said interenga'ged valve elements being the circumambient back end structure of sition with maintenance of a degree of overlap of the free front end of said hood on the back end of said barre1 means.

5. The'sterilized hypodermic syringe assembly as defined in claim 1 characterized by said cap means back end and said head means being shaped to provide when the former is mounted to the latter the front end. sterilizing-fiuid liow passage thereat and openable valve means closing this passage as said blocking means.

6. The sterilized hypodermic syringe assembly as defined in claim 5 characterized by structure of said cap means back end and said head means serving as engaged cooperating valve elements with said cap means back end and said head means being movable relative to each other with maintenance of the amount of said cap means to said head means to a position separable of said valve elements for opening the front end flow passage.

7. A sterilizable hypodermic syringe assembly comprising, in combination; an elongated hollow barrel having head structure closing off one end thereof together defining a parenteral liquid chamber with the other end of said barre1 terminating in circular lateral back end structure defining an open chamber back end, said head structure having cap support means and an outlet passage communicating with said chamber for injective discharge of contents; a removable protective front cap slidably supported on said cap support means and defining with the latter an internal space communicating with the outlet passage, said cap and support means .together closing off said space and outlet passage from communication with the surrounding atmosphere exterior of said barrel and cap with balanced pressures prevailing inside and outside of said assembly and shaped cooperatively-to provide therebetween a first sterilizing-liuid fiow passage leading from the surrounding atmosphere directly to the space within said cap while said cap remains supported on said cap support means to permit pressure flow of sterilizing fluid into and out of the cap space and about structure housed in said cap via the outlet passage and this sterilizing-fluid flow passage, portions of said cap and support means being so shaped and cooperatively engaged to serve as manipulative valve means selectively operable to open and close said passage upon relative sliding motion; piston means slidable in said barrel chamber for injective dischargeof parenteral liquid contents; and back end cap structure slidably carried on and telescopically arranged about said barrel back end protectively covering said lateral back end structure, said piston means being at least partially housed in said hack end cap structure in lateral spaced relation thereto, said back end cap structure and said barre1 back end being so shaped cooperatively to provide therebetween a second sterilizing-liuid flow passage leading across said lateral back end structure from the surrounding atmosphere directly to the back end of the'V chamber and thence into the latter with maintenance of connection of said piston means and back end cap structure to said barre1 to permit pressure liow of sterilizing fluid into and out of said chamber via the second sterilizing-fluid iiow passage, portions of said barrel back end and at least one of said piston means and back end cap structure being so shaped and cooperatively engaged to serve as additional manipulative valve meansselectively operable to open and close the second sterilizingfluid flow passage upon relative sliding motion.

8. A sterilizable hypodermic syringe assembly.y comprising, in combination; a cylindrical barrel having a bore providing a parenteral liquid chamber and head structure at one end closing ofi the bore with the other end of said barrel terminating in circurnambient lateral back end structure defining an open chamber back end, said head structure having fixed axially therein a hollow injective needle having a through bore providing an outlet passage communicating with said chamber for injective discharge of contents, said head structure also having cap support means; a removable protective cap slidably supported on said cap support means and delining with the latter an internal space communicating with the outlet passage, said cap and support means together isolating said space and needle from air-borne bacteria in the surrounding atmosphere exterior of said Ibarrel and cap; means including at least portions of the structure of said cap defining a first sterilizing-fiuid flow passage at=s`aid cap communicating the surrounding atmosphere with saidL chamber via the space within said cap and needle bore while said cap remains supported by said cap support means to permit the pressure flow of sterilizing fluid linto and out of the cap space and about and through said needlehoused in said cap, the means defining the sterilizing-fiuid flow passage having means to prevent ingress of air-borne bacteria in the surround-y ing atmosphere; elongated piston means slidable in said -barrel chamber for injective discharge of parenteral liquid contents; and an elongated back end cap structure having a cylindrical skirt telescoped over and slidably arranged about said barrel back end protectivel'y covering said lateral back end structure, said back end cap structure carrying said piston means coaxially therein in lateral yspaced relation with said barrel back end intervening, said barrel back end and at least one of said piston means and back end cap structure being so shaped and cooperatively engaged to close off the back end of said chamber from communicationwith the surrounding atmosphere with balanced pressures prevailing inside and outside of said assembly, said back end cap structure and the portion of said barrel back end telescoped thereinto being so shaped relative to each other as to provide therebetween a second sterilizing-fiuid flowpassage leading from the surrounding atmosphere between said barrel and captskirt and across said lateral back end structure directlyl to the open back end of said chamber and thence into the latter to permit pressure liow of sterilizing liuid into and out of said chamber via the second flow passage when said back end cap structure and said piston means are retracted relative to said barrel back end to needle carried by and extending coaxially from said head structure with its bore in communication with said barrel bore; an axially-extending annular ange arranged about said needle and extending forward from said head structure; an elongated, needle-protective, interiorly-sterilized cap telescoped back over said needle and having a free edge zone telescoped with said annular fiange closing off said sterilized needle and front end of said barrel bore from air-borne bacteria in the outside atmosphere; a plunger sub-assembly comprising an elongated, cylindrical rear cap having an open front end and a closed back end providing an elongated cylindrical hood telescoped over and slidably mounted in a forward position on said barrel, and an elongated plunger means mounted coaxially in said hood and carried by the closed back end of said rear cap, said plunger means having a sterilized front end thrust forward in said barrel bore to a foremost position 23 adjacent said head structure; flow blocking means car ried by said plunger sub-assembly in engagement with structure of said barrel sealing off the back end of said barrel bore from the outside atmosphere; and cooperating stop means carried by said barrel and said plunger subassembly limiting retraction of said plunger means in said bore, said hood being of a length sufiicient to maintain lapping telescope thereof on said barrel with cooperative engagement of said stop means.

10. A sterilized hypodermic syringe assembly comprising, in combination; an elongated cylindrical barrel having a sterilized bore and a head structure closing off the front end of the bore together defining a chamber for containing parenteral liquid with the back end ofk the barrel being defined by a circular end edge and structurally open when the bore is not plugged; a sterilized, hollow injective needle carried by and extending llongitudinally from the front end of sai'd headstructure-"with its bore in communication with said barrel bore; an' elongated, removable, needle-protective front c'ap telescoped back over said needle and lseparably supported by said head structure in a manner' isolating said sterilized needle from air-borne bacteria inthe outside atmosphere; sterilized, Huid-expelling plunger subassembly structure reciprocatively mounted 'onthe back end of 'said barrel;` said plunger sub-assembly structure comprising an elongated piston post coaxially received in said bore and carrying on its front end piston means snugly and slidably fitted in said bore, and an elongated', cylindrical'skirtcoaxially surrounding said barrel with lintervening annular spacing forward of said barrel back end edge, the back end of ysaid skirt beingcircumferentially mounted lto -vthe back end of said post defining therebetween an annular groove into which the back end edge of said barrel is fitted `in "a duid-tight manner `with balanced pressure `prevailing inside andoutside of said assembly `thereby plugging the barrel bore; and cooperative rstop 'means on said ybarrel and plunger sub-assembly 'structure -limiting retraction of the latter .relative to Asaid barrel; vsaid skirt being of such length as to maintain telescopic lap of said barrel when said plunger structure is retracted tothe limit permitted by said stop means.

l1. A sterilized Vhypodermic syringe assembly comprising, in combination; an elongated cylindrical barrel having a sterilized bore and a head structure closing off the front end of the bore together defining a chamberfor containing parenteral liquid with the backend of the bore being Wide open when free of obstructing piston structure; a sterilized, hollow injective needle carried by and extending coaxially from said vhead structure with its bore in communication with said barrel bore; an elongated, removable, needle-protective, interiorly-sterilized front cap telescoped'back over said needle and separably supported by said head structure in a manner isolating said sterilized needle and the frontend of said barrel bore from air-borne bacteria in the outside atmospheregan elongated, slidable, cylindrical rear cap having an open front end and a closed back end providing an elongated cylindrical hood telescoped over a major portion of said bar- `rel with intervening lateral spacing, the front end of said hood being located in a forward position on said barrel;

elongated plunger means mounted coaxially in and carried by the back end of said hood and including sterilized front end piston means thrust forward in said barrel bore to a foremost position adjacent said head structure; and cooperating means carried by said barrel and hood sealing off communication between the back end of said barrel bore and the outside atmosphere surrounding the assembly in this forward position of said hood on said barrel, the back end of said barrel bore being communicated With surrounding atmosphere viathe lateral space intervening said hood and barrel upon'retraction of said hood and plunger means with maintenance Aofithe telescopic mount 'of said'rear cap onv said barrel.

' vl12. A"sterilizable hypodermic syringe V"assembly cornprising, in combination, barrel means providing a par-- enteral liquid chamber and having head meansA at one end with its other end terminating in circumambient edge means defining an open chamber back end, said head means having an outlet passage communicating withsaid chamber for injective discharge of contents, removable protective cap means supported by said head means with provision of a fiow passage extending from the exterior to the interior of said cap means, iiuid flow-permitting filtering means covering said fiow passage and isolating the interior of said cap means and outlet passage from air-y borne bacteria in the surrounding atmosphere exterior of said barrel and cap means, plunger means reciprocatively vmounted in said chamber through yits open back end,

vand -aplurality of cooperative valve means on said plunger means and said vbarrel lmeans closing off fluid communi- -cation between said chamber and the surrounding atmosphere when said `plunger means is `in-.a forward position in saidV chamber, said valve means being in relative open positions when said plunger means is retracted.

13. -A' sterilizable hypodermic syringe assembly coniprising, in combination, barrel means providing a parenteral liquid chamber and having head` means at one end with its other end v'terminating in circumambient edge means defining an open chamber back end, said head means having an outlet passage communicating with said chamber for injective discharge of contents, removable protective cap means supported by said head means and having a ilow passage extending'through a wall portion thereof, uid flow-permitting filtering means in said cap means vcovering said flow passage and isolating the interiorfof said cap means and outlet passage from airborne bacteria in'the v'surrounding atmosphere exterior of said barrel and cap means, plunger means reciprocatively mounted in said chamber through-its open back end, vand a plurality ofV cooperative valve means on said plunger `means and said barrel means closing off fluid communication'between said chamber and the surrounding atmosphere *when 'said plunger means is in a forward position in said chamber with balanced pressures prevailing in- `side'and outside of said chamber, the valve means on one of said plunger and barrel means being elastic to permit automatic opening for allowing fluid ow therepast under lconditions of appreciable differential in pressures present inside and outside of lsaid chamber.

' 14. A sterilizable hypodermic syringe assembly comprising, lin combination, barrel means providing a parenteral liquid chamber and having head means at one end with its other end terminating in circumambient edge means 'defining an open chamber back end, said head 'means having an outlet passage communicating-with said vchamber for Vinjective discharge of contents, removable protective cap `means supported 'by said head means and having a flow passage extending through a wall portion thereof, Huid flow-permitting filtering means in said cap means coveringsaid flow passage fand isolating the interior of said cap means and outlet passage Vfrom airborne bacterra in the surrounding atmosphere exterior of said barrel and cap means, plunger means reciprocatively mounted `in said'chamberthrough its open back end, stop means cooperatively located on said plunger and barrel means limiting retraction of the former in the latter, and elongated hood means carried by said plunger means with 'telescopic lap over said barrel means in all positions of means having anroutlet passage communicating with said 25 chamber for injective discharge of contents, removable protective cap means supported by said head means and having a liow passage extending through a wall portion thereof, tiuid flow-permitting filtering means in said cap means covering said flow passage and isolating the interior of said cap means and outlet passage from airborne bacteria in the surrounding atmosphere exterior of said barrel and cap means, plunger means reciprocatively mounted in said chamber through its open back end, stop means cooperatively located on said plunger and barrel means limiting retraction of the former in the latter, and elongated hood means carried by said plunger means with telescopic lap over said barrel means in all positions of said plunger means between its forward position in said chamber and its'retracted position as determined by said stop means, said hood and plunger means providing with said barrel back end edge means an automatic pressureoperable iiuid iiow valve means with said hood and plunger Y means thrust to their forward positions, said valve means in the forward positions of said hood and plunger means being closed with balanced pressures prevailing inside and outside of said assembly and openable by a differential in such pressures.

16. A sterilzable hypodermic syringe assembly comprising, in combination, an elongated cylindrical barrel having a bore providing a parenteral liquid chamber deiined at one end by a head structure closing oif the front end of the bore with the back end of the latter open when not plugged and defined by a circular end edge; a hollow injective needle carried by and extending co-axially from' said head structure with the lumen thereof in communication with said chamber; an elongated, needle-protective cap telescoped back over said needle and removably iitted to said head structure in a Huid-tight' manner and having a tip extending beyond the free end of said needle provided with a through hole defining a flow passage, said tip carrying internally thereof fluid dow-permitting iiltering means covering said ow passage and isolating the interior of said cap and the needle housed therein from airborne bacteria in the surrounding atmosphere exterior of said barrel and cap; plunger means reciprocatively carried by the distal end of said barrel having a piston stem and head carrried by said stem slidably mounted in said bore chamber and an elongated cylindrical hood co-axially arranged about said stem and mounted on the distal end of the latter; stop means cooperatively mounted on said stern and in said barrel limiting retraction of said plunger means to a retracted stop position with the stem head retained in said bore chamber, the free proximal end of said hood having telescopic lap over said barrel in all positions of said plunger means between the forward position of said stem head in said chamber and the retracted stop position thereof; and valve means selectively closing off the back end of said barrel bore including an annular groove deiined between the distal ends of said stem and hood into which the distal end edge of said barrel is jammed in Huid-tight manner when said plunger means is thrust forward to its forward position.

17. A sterilizable hypodermic syringe assembly comprising, in combination, an elongated cylindrical barrel having a bore providing a parenteral liquidy chamber defined at one end by a head structure closing ofi the front end of the bore with the back end of the latterv open when not plugged and dened by a circular end edge; a hollow injective needle carried by and extending co-axially from said head structure with the lumen thereof in communication with said chamber; an elongated, needle-protective cap telescoped back over said needle and removably fitted to said head :structure in a liuid-tight manner and having a tip extending beyond the free end of said needle provided with a through hole defining a ow passage, `said tip carrying internally thereof fluid How-permitting filtering means covering said ow passage and isolating the interior of said cap and the needle housed therein from 26 i airborne bacteria in the surrounding atmosphere exterior of said barrel and cap; plunger means reciprocatively carried .by the distal end of said barrel having a piston stem and head carried by said stem slidably mounted in said bore chamber and an elongated cylindrical hood coaxially arranged about said stem and mounted ou the distal end of the latter; stop means cooperatively mounted on said stem and in said barrel limiting retraction of said plunger means to a retracted s-top position with the stem head retained in said bore chamber, the free proximal end of said hood having telescopic lap over said barrel in all positions of said plunger means between the forward position of said stem head in said chamber and the retracted stop position thereof; and valve means closingoff the back end of said barrel bore including an annular groove defined between the distal ends of said stem and hood and the distal end edge of said barrel telescoped into said groove, the d-istal end edge of said barrel being formed of elastic material with the external diameter of the root of said stem defining the inner wall of said groove being greater than the internal diameter of the barrel distal end edge for swelling tit of the latter thereover and with the .internal diameter of the hood at its distal end being greater than the external di-ameter of said barrel distal end edge to permit this swelling fit, said back end valve means being closed'when said plunger means is thrust to its forward position with balanced pressure prevailing inside and outside of said chamber and being automatically openable for allowing iiuid flow therepast under conditions of appreciable differential in pressures present inside and outside of said chamber.

18. A sterilized hypodermic syringe assembly comprising, in combination, an elongated cylindrical barrel of elastic material having a sterilized bore and a head structure closing oilt the proximal end of the bore with the distal end of the latter open when not plugged, said barrel carrying on the wall of its bore forward of the distal end thereof inwardly-projecting stop means to define between it and said head structure a chamber for parenteral liquid; a sterilized, hollow injective needle having a free insertable proximal end and a distal end carried by and extending iso-axially through said head structure with the lumen thereof in communication with said chamber; an elongated, needle-protective, interiorly-sterilized cap telescoped back over said needle and having a distal end removably iitted to said head structure in a substantially fluid-tight manner, the other end of said cap providing a tip extending forward of the proximal free end of said needle and having a hole extending therethrough providing a How pass-age, said tip carrying therein a sterilized wad of porous filtering material covering said ow passage and isolating the interior of said cap and said needle from airborne bacteria in the surrounding atmosphere exterior of said barrel and cap; an elongated, cylindrical hood having an open proximal end telescoped over and slidably mounted about said barrel and a closed distal end; a plunger stem supported by said hood distal end co-axially within said hood and carrying a sterilized piston head reciprocatively mounted in said chamber between said head structure and said stop means; abutment means carried by said stem cooperating with said stop means limiting retraction of said stem and its head in said chamber with the open proximal end of said hood telescoped over and lapping about said barrel in all positions of said piston head in said chamber forward of said stop means; and barrel bore plugging means on the distal end of said stem .telescopedinto the distal end of said barrel when said piston head is thrust forward to -the vicinity of said head structure with the elastic barrel distal end edge swelled out about said plugging means and providing therewith la valve openable by differential in pressures inside and outside of said chamber with said hood at its distal end having an internal diameter appreciably greater than the external diameter of said swelled edge to permit further valve-opening pressure swelling of the latter Awithout appreciable axial motion of said piston head in said chamber. l

19. A sterilizable hypodermic syringe assembly comprising, in combination; cylindrical barrel means providing a parenteral liquid chamber and having head structure at one `end with i-ts other end `terminating in circumambient lateral back end structure deining an open chamber back end, said head structure having tixed axially therein a hollow injective needle having a through bore providing an outlet passage communicating with said chamber for inj'eetive discharge of contents, said head structure carrying cap support means; a removable proteotive cap slidably supported on said cap support means and detining with the latter an internal space communicating with the needle bore outlet passage, said cap and support meansto-gether` isolating said space and needle from airborne bacteriain the surrounding atmosphere exterior of said barrel and cap, a. wall portion of said cap having a through hole providing a first sterilizing-uid passage communicating the surrounding atmosphere with ksaid chamber via the space withinsaid cap and needle bore to permit pressure dow of sterilizing uid into and iout'of the cap space and about and through said needle housed in said cap; -o-w-pelmitting ltering means covering said sterilizing-uid passage to prevent ingress of airborne bacteria in the surrounding atmosphere; elongatedpiston means slidable in said barrel chamber for injective discharge of parenteral 'liquid contents; and an elongated hood structure having a cylindrical skirt telescoped over and slidably mounted on said barrel back end, carrying said piston means co-axially therein and kprotectively covering said lateral Abarrel back end structure, said hood structure and lateral barrel back end'structure together lclosing off the back end of said chamber fromcom- :anced pressures prevailing inside and outside of said yas- ;sembly and cooperatively providing therebetween a 4second sterilizing-uid passage leading from the surround-v ing atmosphere between said barrel and hood skirt `and :across said lateral barrel back end structure directly to the Iopen back end of said chamber and thence into the latter to permit pressure tiow of sterilizing fluid into and out of said chamber via the second passage, portions of -said hood structure and said lateral back end structure cooperatively serving as valve means selectively operable to` open and close the secondpassage.

20. A sterilized hypodermic syringe assembly comprising, in combination; an elongated cylindrical barrel having a sterilized bore and a head structure closing olf the front end of the bore with the back end of the latter open when not plugged; a sterilized, hollow injective needle having a proximal inserting free end and a distal end carried by and extending co-axially through said head structure with its lumen in communication with said barrel bore; an axially-extending annular flange arranged about said distal endl of said needle and extending forward from said head structure; an elongated, needleprotective, interiorly-sterilized cap telescoped 'back over said needle and having a distal free edge Zonetelescoped with said annular flange isolating said sterilized needle and front end of said barrel bore from air-borne bacteria in the outside atmosphere, said cap having a proximal tip forward of the proximal free end of said needle provided with a through hole and carrying interiorly thereof a sterilized body of porous ltering material intervening the hole and the proximal free end of said needle; an elongated, cylindrical hood having an open proximal end and a closed distal end telescoped over and slidably mounted in a forward position on said barrel; elongated plunger means mounted co-axially in said hood and including sterilized front end piston means thrust forward in said barrel bore to a foremost position adjacent said head structure; barrel bore plugging means on the back ends of said barrel and plunger means sealing ofi the back end of said barrel bore from the outside atmos- 28 phere;and cooperating stop .meansin said barrel bore in the vicinity of the back end of the latter and on said plunger means in the vicinity of the front end 'of the latter limiting retraction of saidplunger means in said bore, said hood being or a length suicient to maintain tion with said barrel bore; an elongated, removable;

needle-protective front cap telescoped back over said needle and separablyeupported by said head structure in a fluid-tight mannensaid cap having a tip provided with a'through'hole and carrying behind the hole a sterilized wadA of flow-permitting lter material isolating said sterilized needle vfrom airborne bacteria in the outside atmosphere; sterilized, huid-expelling plunger Ystructure reciprocatively mounted Ainthe back end of said barrel bore; said plunger structure comprising an elongated piston post co-axially received in said bore and carrying on its front end piston means snugly and slidably vfitted insaid bore, and an elongated, cylindrical skirt co-axially surrounding saidy barrel and post and circumferentially mounted to the back end of the latter together deningtherebetween an annular groove into which the elastic back end edge of said barrel is fitted in` a Huid-tight. manner with balanced pressures prevailing inside and outside of said assembly; and cooperative stop means .on `said barrel and plunger structure limiting retraction of the latter relative to said barrel, said skirt being of such length as to. maintainV telescopic lap of. said barrel when said plunger structure is retracted to the limitk permitted by said stop means. l

22.'A sterilizuble hypodermic syringe assembly comprising' in combination; cylindrical borrel means providing a parenteral liquid chamber and having head means otono and `with its other end terminating in crcumambient edge means defining un open chamber back end, said head meanshaving an outlet passage communicating with said chamber for infective discharge of contents; removable protective cap means temporarily supported by said head means with a front end flow passage debited at least in part by structure of one of said cup and head means and communicating with said outlet passage and the outside atmosphere; front end flow passage blocking means for preventing'flow of bacteria-laden oir through said outlet passage and isolating the interior of said cop means from airborne bacteria in the outside atmosphere; and plunger sub-assembly means including piston means slidably und snugly mounted in u forward position in said chamber for drawing fluid thereinto upon retraction to a rearward position andlexpelliug fluid therefrom upon foiward thrust to its forward position, elongated plunger stem means extending through the open back end of said chamber und carying said piston means on its front end, and an elongated hood having an open front end with its back end being closed and carried by the back end of said plunger stem means, said hood having a fixed cylindrical shape and surrounding a major portion of said stem means with an annular space defined therebetween into ywhich the bock end of said barrelfmeans is telescoped, thelopen from end of said hood having telescopic lap over said barrel in all positions of said plungersub-assembly between the forward position of said piston means in said chamber and the retracted position thereof, the inside diameter of said hood beiugslightly greater than the outside diameter -of said barrel to define an annular space between the hoodand-the barrel through lwhich a sterilz- 29 ing gas may pass from the outside atmosphere to the open chamber back end of said barrel.

23. A sterilizable hypodermic syringe assembly comprising, in combination; cylindrical barrel means, providing a parenteral liquid chamber and having head means at one end with its other end terminating in circumambient edge means defining an open chamber back end, said head means having an outlet passage communicaring with said chamber for infective discharge of contents; removable protective cap means temporarily supported by said head means and covering said outlet passage and isolating it from airborne bacteria in the outside atmosphere; and plunger sub-assembly means including piston means slidably and snugly mounted in a forward position in said chamber for drawing fluid thereinto upon retraction to a rearward position and expelling fluid therefrom upon forward thrust to its forward position, elongated plunger stem means extending through the open back end of said chamber and carrying said piston means on its front end, an elongated hood having an open front end with its back end being closed and carried by the back end of said plunger stem means, said hood having a fixed cylindrical shape and surrounding a major portion of said stem means with an annular space defined therebetween into which the back end of said barrel means is telescoped, the open front end of said hood, having telescopic lap over said barrel in all positions of said plunger sub-assembly between the forward position of said piston means in said chamber and the retracted position thereof, the inside diameter of said hood being slightly greater than the outside diameter of said barrel to define an annular space between the hood and the barrel through which a sterilizing gas may pass from the outside atmosphere to the open chamber back end of said barrel, and

30 cooperating sealing portions on said barrel means and said plunger sub-assembly, said sealing portions fitting tightly together and sealing ofi communication between said open chamber back end and the outside atmosphere only when the plunger sub-assembly is thrust to its forward position.

References Cited in the tile of this patent or the original patent UNITED STATES PATENTS 715,290 Porter ..-e Dec. 9, 190-2 766,121 Stearns July 26, 1904 1,059,493 Selleck Apr. 22, 1913 1,718,592 Smith June 25, 1929 2,263,865 Bailen Nov. 25, 1941 2,375,929 Lautenschlager May 15,- 1945 2,453,590 Poux Nov. 9, 1948 2,490,447 Lockhart Dec. 6, 1949 2,524,363 Smith Oct. 3, 1950 2,539,510 Friden Jan. 30, 1951 2,578,814 Kollsman Dee. 18, 1951 2,626,604 Nadeau Ian. 27, 1953 2,646,043 Heitg-Husler et al July 21, 1953 2,685,878 Seifert et al. Aug. 10, 1954 2,688,965 Huber Sept. 14, 1954 2,700,386 Ogle Ian. 25, ,1955 2,715,905 Ogle Aug. 23, 1955 2,727,514 Lockhart Dec. 20, 1955 2,847,996 Cohen et al Aug. 19', 1958 FOREIGN PATENTS 167,058 Germany Ian. 13, 1906 887,677 France 4---- Aug. 16, 1943 813,433 Germany Sept. 13, 1951 Austria Aug. 25, 1952

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