US2714887A - Intradermal injector - Google Patents

Description

Aug. 9, 1955 2,714,887

A. VENDITTY INTRADERMAL INJECTOR Filed April 26, 1954 wf H f A /nvezzzfor zzf/zoy vena/159) 9,5%, mm #am jya United States Patent O INTRADERMAL INJECTOR Anthony Venditty, Detroit, Mich., assignor to R. P. Scherer Corporation, Detroit, Mich., a corporation of Michigan Application April 26, 1954, Serial No. 425,699 3 Claims. (Cl. 12S-173) This invention relates to a hypodermic injector of the needleless type which is adapted to inject subcutaneously a very small quantity of uid in the form f a high pressure jet. More particularly, the invention is an adaptation of the hypodermic injector described in copending application Serial No. 94,579, liled May 21, 1949, by R. P. Scherer, which adaptation renders the injector suitable for allergy testing. j

The conventional hypojet injector described in said copending application is adapted to inject the entire contents of an ampule (1 cubic centimeter) secured within the nose of the instrument, relatively deep beneath the skin and into the muscles. For certain uses it is desirable to inject only a very small quantity of liquid intradermally. The structure of the present` invention is especially suitable for administering hypodermic injections of the latter type.

It is an object of the present invention to provide a plunger means within the injector for forcing an accurate predetermined portion of the fluid within the containing ampule through the oriiice in the end thereof.

Another object is to provide a plunger means of the type described which may be removably secured within the dosage sleeve of a standard hypojet instrument, above referred to.

These and other objects will become apparent from the following description when read in conjunction with the accompanying drawings, in which:

Figure l is an enlarged sectional view through a hypojet injector of the type shown in the above-mentioned copending application showing the rear half thereof, and

Figure 2 is a similar sectional view of the ampulecontaining end of the injector and a continuation of the right-hand end of Figure 1, both Figure 1 and Figure 2 showing the parts in latched position.

Figure 3 is a sectional view taken along the line 3-3 of Figure 1.

Figure 4 is a perspective View of the plunger of the invention in association with the lower body portions of the injector, with the plunger rod shown in advanced position in broken lines.

Referring generally to the injector Shown in Figures 1 and 2, the numeral 10 designates a body housing `most of the mechanism of the injector. A dosage sleeve 12 is screwed onto the threaded forward end of the injector and a winding sleeve 14 is rotatable on the rear end thereof. The sleeve 14 has an inturned flange 16 coacting with an annular shoulder 18 on the body 10 to prevent longitudinal movement in one direction relative to the body. A latch housing 20 is screwed into the rear end of the winding sleeve 14 with a thrust bearing assembly 22 interposed between the body and the latch housing.

A release button cap 24 is threaded on the latch housing Ztl and the entire assembly of the winding sleeve 14, `latch housing 20 and cap 24 is held in assembled relation by a set screw 26 engaging all three parts and sealed in place as best shown in Figure 3.

The dosage sleeve 12 has threaded on its forward end an ampule holder 3h adapted to receive an ampule 31 having medicament 32 therein and a flexible cup-like follower 33, preferably formed from an Oil resistant rubber such as polychloroprene, or the like. The ampule is provided with a reduced discharge nozzle 34, perforated by a minute discharge orifice 35. The ampule holder is covered by a resilient nose 36 which may also be made from polychloroprene rubber.

The internal mechanism of the injector includes a cylindrical plunger 4t) slidably mounted within the disc or bearing member Si) screwed into the dosage sleeve 12, said plunger being adapted to propel the follower 33 in the ampule 31 thereby discharging or ejecting a fine stream or jet of liquid 32 through the minute orice 35 in the outer end of the ampule. It will be noted that the inner end of the plunger 40 has a shank 41 of reduced diameter which slides longitudinally within the opening 42 in the center of the disc or bearing member 50. The bearing member 50 may take the shape of a cup with a central hollow shaft for the plunger bearing, and externally-threaded side walls that screw inside the dosage sleeve l2. A disc 43 fixed to the end of shank 41 limits the forward movement of the plunger 40 while the shoulder 44 limits the rearward movement of the plunger. The maximum distance the plunger may be propelled, therefore, is equal to the difference between the length of the shank 41 and the thickness of the disc 50. ln Figure 2, where the plunger 4i) is shown in retracted position, this distance is indicated by the numeral 47. The distance 47 may be varied in. accordance with the volume of the liquid desired to be ejected from the ampule by providing a different plunger having a shank 41 of increased or decreased length.

The mechanism for propelling the plunger 40 comprises a nut 60, a screw 62 and a plurality of power springs 64. The nut is sleeve-like in character and has a disc-like head 66 provided with spring seats for the springs 64, which springs at their opposite ends seat against a partition 68 of the body lll.

The nut 61B has threads 61 at its left end, as shown in Figure l, which cooperate with the threads of the screw 62. Nut 60 will not rotate with respect to the body lil, but is adapted to move longitudinally therein. The screw at its left end, as shown in Figure l, is provided with a head 70 providing a latching shoulder 71. The screw head 7d terminates in a bifurcated portion which results in a pair of spaced blades 72, the head with its blades being slidable in a square opening 21 of the latch housing 20. As shown in Figure 3, the latch housing is provided with a cross slot 23 in which a latch. 25 is pivotally r, mounted. For this purpose a pivot pin 27 is press-fitted in the latch and has its ends rotatable in the latch housing. The latch substantially spans the width of the slot 23 and the space between the blades 72 of the screw, and is of the shape shown in Figure 1, having a latching shoulder 75 and a spring socket 76. A latch spring 77 has one end seated in the socket and its other end seated in an opposing socket 78 of the latch housing for tending to rotate the latch counterclockwise.

Slidably mounted in the release button cap 24 is a release button 80 having a crossbar 82 attached thereto and slidable in the slot 23 of the latch housing 20 and the space between the blades 72 of the screw 62 back of the latch 25. When the button 80 is depressed, the latch 25 is rocked against the bias of the spring 77.

A latch roll 83 rotatably mounted in the latch housing prevents the screw 62, which is biased to the right by springs 63 from moving until the latch 25 is released,

3 thus` permitting` the latch roll 83 to rotate out from under the shoulder 71.

The body has five circumferentially spaced posts 90 which extend beyond the threads 11 and engage the bottom of the disc 50, as shown in Figure 4. The posts may be formed by cutting spaced longitudinal slots in theV wall of thebody. Bosses 52 triangular in shape, project from. the bottom` of disc 50 between the posts 9.0' to prevent rotation between the body 10 and the disc 5.0. Thus, when the dosage sleeve 12 is turned it rotates with respeelt` to both thebody 10,y and the disc 50.

In operation, the ampule 3 1 is placedv withiny the holder 'and1securedto the end of the injector., The Winding sleeve 141is rotated, causing the screwv 62: to turn and lift the nut 66 to compress the springs 64; The. dosage sleeve is then; rotated to bring the ampule follower 33 into firm contactwith the end of the: plunger 40. The increaseV ILOIQUC. IGSStanCe 0f: the sleeve when the plunger meets theresistance of' the follower indicates when firm contact isA obtained; The; follower should be fitted tightly withinI the ampule for this purpose.

The plunger is shifted with respect to. disc 50 by this operation so that the disc43 on the end thereof is spaced from theV disc 5,0 the distance 47 shown in Figure l. Release is accomplished by depressing the button 80 which permits4 the latch roll 83' to rotate out from under the shoulder 71. Thev springs.63 immediately expand causingA thenut 66 to be propelled within the body 10 and strike the disc'lry a sharpblow. The plunger 40 and the follower 33 are thus propelled a predeterminedv distance, that is, the distance between the disc 43` and the disc 50. In this way an accurate volume of. medicament is ejected from the orifice of the ampule.

Thev construction described is particularly useful for making allergy injections in which the volume of medicament. discharged is about one-iiftieth of a cubic centimeter. This volume may, of course, be increased or decreased by lengthening or shortening the length of the shaft 41 ofthe plunger 40; Obviously, other means may be used to limit the longitudinallmovement of the plunger, the construction shown being just` one convenient means for doing so, Any suitable stops'rxed securely tothe circumference ofthe plunger will serve for this purpose.

The depth; ofthel injection may be controlled by adjusting the winding sleeve to vary the distance between the nut66 and the disc 43. Increasing the distance will further compress the springs to increase the impact of the blow and` this in turn increases the pressure at whichk the liqilid is ejected. Where the liquid volume is small,

the depthy of penetration will necessarily be shallow, usually within` the intradermal range.

layer of skin.

Sincehe. normal volume of an ampule is one cubic centimeter, itis apparent that a large number ofV intradermal injectionsof the allergy type may be adminis,-

tered from a. single ampule. If the injections are not` given successively, as when different medicaments are= It will be noted that the plunger and the associated..

disc 50 may be conveniently removed from the instru- Of, course, the, pressure must be; sufficientto penetrate the-,tough outerV ment by screwing olf the dosage sleeve 12, and screwing the. disc. 5,0 out ofthe sleeve. In. this way other plunger assemblies providing longer or shorter plunger travel may be substituted to increase or decrease the volume of medicament discharged from the ampule.

Various modifications of the structure illustrated will become apparent to those skilled in the art. It is not Amy intention, therefore, to limit the invention to the particular formA illustrated, other than as necessitated by, the scopev of the appended claims.

I claim:

l. In a hypodermic injector, an assembly comprising an elongated body, an ampule holder detachably connected to one endfthereof andy adaptedtoehold an oriliced ampule, a plunger slidably mounted within. a bearing member threadedly engaged with the inside wall of said body and adapted for engaging and propelling a follower in the ampule to discharge liquid from the ampule through a dischar-ge-or-ilicel therein, said'bearing member being adapted to-- rotate ons-aid threadsI to bring said plunger-into firm contact with said follower, meansk for propelling said plunger including means` forr` storing the driving energy therein, means for suddenly releasing the energy thus storedtoper-fbrm propulsion ofthe plunger andlfollower, and stop means for limiting movementv of said plungerwith respect to said bearing member whereby ameasured portion of liquid=V is; dischargedk fromV said orifice.

2'; ln a hypodermic injector, an assembly comprising an elongatedV body, an` ampulef holder detachably connectedftoone; end thereof and adapted to hold an orificed ampule, said body containing al cylindrical plunger adaptedfor-Y engaging and propelling afollower Within the ampule, said plunger having a shank of reduced diameter andpredeterminedllength slidably'mounted within a bearing member, said shanlterminating` in shoulders on either sideof said' bearing-- member whereby the longitudinal movement of said plunger with respect to said bearing memberJ iselimited', the'said' bearinggmember being threadedly engaged'w-iththe-insidefwall ofV said body to permit movingfth'e plungerfinto-iirm4 contact withsaid follower, means fon propelling*y said plungerincludingmeansv for storinglthedrivingtenergyftherein, andmeans for suddenly releasing the energy thus stored to perform propulsion off'thei plunger andifollower,` whereby a measured portion ofliquidri'sdischarged from said oriiice.

3. In a hypoderrnic: injector,- an assemblyV comprising anelongaterlbodyexternallyv threaded at one end, adosagefsleevefadapted toiscrew ontosaid.- threaded portionof` thefbotyyand. carryingan ampule'vholder inthe end oppoy site the body adapted to hold an orificed ampule, said dosage; sleeve containing1 af plunger: slidably mounted withirria disc; threadedly; engagedfwithvthe. inside wallof saidlsleeve, ,and adapted'for engagingandpropelling a follower in the ampuleto" dischargeliquid therefrom, posts projecting fromthe'; threaded end of. said. body to `engage said disc to prevent rotation of the disc with respecttof the body, meansarried by saidy bodyfor propellingV said plunger.V including; means for storinggthe driving energy therein, means, for4 suddenly releasing theY energy thus stored to perform propulsion of the. plunger and follower, and stop means, for limitingmovement of said plunger withrespectto saidfdiscwhereby a measured portion of liquid is4 discharged from said orifice.

No references; cited'.

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