US3055362A - Hypodermic injection apparatus - Google Patents

Description

Sept. 25, 1962 J. w. H. UYTENBOGAART f 3,055,362

A 4 HYPODERMIC INJECTION APPARATUS Filed May 16, 1956 3 Sheets-Sheet 1 I ATTORNEYS Sept. 25, 1962 1. w. H. UYTl-:NBOGAART 3,055,362

HYPODERMIC INJECTION APPARATUS Filed May 16, 1956 3 Sheets-Sheet 2 l INVENTOR g Jvhuunzs /Y/l Vgmggaar Y kw, 5M MKM ATTORNEYS Sept. 25, 1962 J. w. H. UYTENBOGAART 3,055,362

HYPQDERMIC INJECTION APPARATUS 3 Sheets-Sheet 3 Filed May 16, 1956 Netherlands, assigner to Auguste Reoseboom, New Yorlk,N.Y.

Filed May 16, 1956, Ser. No. 585,284 8 (liaims. (Cl. 12S--218) This invention relates to a structurally and function- `ally improved hypodermic injection device which, according to certain aspects, will embrace alternative and/or improved structure over lthat disclosed in my prior application for United States Letters Patent, Serial No. 410,662, filed on February 16, 1954, now Patent No. 2,960,087.

By means of the present teachings, ian apparatus is furnished which may readily be loaded, discharged and reloaded, the entire cycle being accomplished by a power mechanism which may be repeatedly operated, either by `the attending physician or the patient. Moreover, in the discharge phase of the operation, it will be feasible for `the operator to secure an automatic functioning of the parts under which needle penetration and aspiration will initially occur. Thereupon, the cycle will be automatically interrupted to enable a user to determine whether the needle has lodged in a vein.

After this has been determined, the functioning of the apparatus may be re-initiated to assure of a discharge of medicament through the lumen of the needle and an `automatic withdrawal of the latter from the tissues. That discharge may be controlled so that a complete or an elected fractional dosage of medicament is injected.

Moreover, by the present teachings, a mechanism is provided in which the parts may be set by the user to dispense with any aspirating function. Under these circumstance-s, the discharge phase of the mechanism will embrace needle penetration of the epidermis and underlying tissue, a discharge of the medicament upon the needle having reached a proper depth and an automatic withdrawal of the needle from the tissue, all in response to a single actuation of the triggering mechanism.

Thereupon, an operator may open the apparatus and remove the spent ampule and used needle therefrom; these being replaced by 'a fresh ampule-needle unit. Regardless of the manner in which the apparatus is actuated, the patient will experience only a minimum amount of pain and the injection will be achieved with maximum efficiency.

Among other objects of the invention are those of furnishing =a device of this type which will include relatively few parts, each individually simple and rugged in construction; those parts being capable of ready assemblage to furnish a unitary apparatus functioning over long periods of time with freedom from all difficulties. As part of the assembly, a medicament-containing ampule assembly will be included which will have novel and desirable characteristics.

With these and other objects in mind, reference is had to the attached sheet-s of drawings illustrating one practical embodiment of the invention and in which:

FIG. l is an edge view of the apparatus;

FIG. 2 is a side elevation thereof;

FIG. 3 is a rear view of the unit;

FIG. 4 is a front view of the same;

FIG. 5 is a fragmentary sectional elevation of the rear portion of the apparatus with certain of the parts removed or broken away to disclose underlying elements.

FIG. 6 is a sectional plan view taken along the line 6-6 in the direction of the arrows as indicated in FIG. 5,

FIG. 7 is a sectional side view taken along the line 7-7 in the direction of the arrows as shown in FIG. 1;

aten

FIG. 8 is a sectional plan view in enlarged scale and showing the operation of loading the unit;

FIGS. 9 and 10 lare transverse sectional views taken along the lines 9-9 and 10--10 respectively in the direction of the arrows as indicated in FIG. 8;

FIG. 11 shows the position `assumed by the parts during the discharge of medicament;

FIG. l2 is a partly sectional side View of the coupling mechanism whereby fractional dosages may be achieved in addition to permitting of an aspirating function; and

FIG. 13 is a side elevation of certain of `the parts as shown in FIG. 12.

Referring primarily to FIGS. 1 and 2, thenumeral 15 indicates a casing preferably formed of metal and in line with an upper edge of which aninjection tube 16 is secured. The latter provides adjacent its outer end a nose orcontact portion 17 which may be formed of a material other than metal `and has its surface ridged. At a point adjacent the outer end of this tube,openings 18 are formed therein. The lower portion ofcasing 15, as viewed in FIG. 2, supports on its `forward face acap 19. Extending from its rear face is the actuatinghead 20 of `a valve member positioned withincasing 15.

A control or trigger mechanism terminates in ahead 21 extending beyond the rear ofcasing 15 and providing a shiftable actuator. This head is connected to a stem provided with a notch 22 (FIG. 7). A safety is furnished by conveniently employing aplate member 23 pivotally supported as at 24 on the rear face ofcasing 15 and provided with an opening, the edge of which may enter notch 22 to thereby obstruct an inward shifting ofhead 21. As especially shown in FIG. 5,plate 23 carries apawl 27 in the form of a spring. This engages with the teeth of anannular ratchet 28. These teeth 'are also engaged by aholding pawl 29 having its end secured against movement with respect tocasing 15. Therefore, a retrograde movement of the ratchet aroundpivot pin 30 is prevented. Aplate 31 is attached to the ratchet conveniently bybolts 32. This plate may carrysuitable indicia 34 capable of being registered with anindex mark 35 associated with the face of the casing.

Thus, it is apparent :that ifplate 23 occupies a position at which one end of itsslot 26 is engaged by the shank or stem ofscrew 25, that plate will rest within notch 22 of the trigger element. Now, whenplate 23 is shifted aroundpivot 24 to a point where the stem ofelement 25 abuts the opposite end ofslot 26,pawl 27 engaging one of theteeth 28 of the ratchet will shift the latter around itspin 30. A return movement will be prevented by means ofpawl 29. So shifted,plate 31 will be rotated to register a'graduationlof indicia 34 withmark 35 which indicates that the plate has been advanced, for example, the distance of one pawl tooth.

4Attention is next invited to FIG. 7 in which it will be seen that interveningcap 19 andactuator 20, a space is provided withincasing 15. Within this space, acartridge 36 is disposed. That cartridge may embrace a small flask containing liquid Freon. a certain :amount of which may have been converted to a gas. Theflask 36 supports la Sealing cap or extension 37, terminating in a pierceable diaphragm portion. A valve is provided by employing a 'body 38 which is threaded to cooper-.ate with threads formed incasing 15. This body carries an O-ring 49 having face contact with the adjacent cavity surface when body 38 is fully projected in an inward direction. As will be understood in connection with theflask 36, when the diaphragm of the latter is punctured, Freon gas escapes therefrom and expands thereby reducing the internal pressure within the flask. This results in more liquid within the latter converting into gas to bring the pressure up to substantially the original value. This operation may be continued until all of the liquid is exhausted. Thereupon, the pressure of the Freon gas diminishes. Obviously, the ask should be mounted in a manner such that liquid Freon does not directly discharge therefrom under normal manipulation of the parts.

Body 38 is affixed toactuator 20 and has a pointed extension which serves to perforate the end of tip 37 and to cooperate with the thus formed opening and adjacent casing surfaces as a valve. Extending from part 38, a passage 39 is provided which communicates with a bore 40. The stem supportingactuating head 21 is continued at 41 within bore 40. A spring 42 within this bore serves to normally maintain this stem in a projected position. A passage 43 extends from bore 40 to abore 44 in line withinjection tube 16.Bore 44 is enlarged adjacent its forward end to provide acylinder portion 45. Within the latter, the rear end of apiston assembly 46 is disposed. Aspring 47 of the contraction type has one of its ends secured to this assembly. Its opposite end is attached to an anchoring unit 48 adjacent the rear end ofcasing 15.

Suitable packing such .as vO-rings 49 may be associated with the several parts to prevent leakage of fluid under pressure into the outer atmosphere. These packings also serve in association with stem 41 as a valve to control the ow of liuid from passage 39 to passage 43. It will be observed, having in mind the proportions of stem 41 and the arrangement of the packing, that a balanced cone dition will prevail, such that the operator will not have to overcome pressures when desiring to project theactuator 21. Rather, with the shifting ofplate 23 to a point where it does not extend into notch 22, merely spring 42 will urge stem 41 in an outward direction. As the stem shifts to compress this spring, gas will of course be free to flow past valve 38 to thebore 44 if the actuating head orpart 20 of that valve 38 has been shifted to retract the parts to permit an escape of fluid fromflask 36. The packing 49 in association withpiston portion 46 also serves to prevent a seepage of fluid under pressure past that piston. As illustrated in FIG. 7, a spring-presseddetent 50 may bear against the rear face ofplate 23 to normally retain the latter in a position where a shifting of stem 41 is prevented.

Medicament is dispensed by the present apparatus by means of an ampule-needle assembly, a preferred form of which is illustrated in its initial condition in FIG. 8. It will be seen that the `ampule conveniently involves atransparent tube 51 of glass which has its forward end reduced to define aflange 52 beyond which aneck portion 53 extends. This neck portion terminates in a bead or lip 54. The bore of the neck is closed by a stopper having itsplug 55 extending into the same. The head 56 of this stopper overlies the forward face of lbead or lip 54. Formed centrally of the head 56 anextension 57 may be provided integral with the material of the stopper. A double-pointedcannula 58 has secured to it, at a location short of its inner end, ahub 59. This hub is enlarged to provide a rear portion 60 which has a diameter such that it may slidably receive the head 56 of the stopper as well as the bead 54. Its length should be such that its inner edge will lie immediately adjacent shoulder orange 52 when the hub is fully seated. At points short of this inner edge, hub portion 60 is formed with slits defining tongues orpawls 61. The hub being made of metal and these tongues being biased to have their free ends tend to occupy a space within hub portion 60, it follows that with these ends extending in the direction ofhub portion 59, they may cam against and override bead 54. Their length being properly proportioned, such overriding will occur whenneck 53 is substantially completely ensleeved within hub portion 60. As they are moved in this manner, it is apparent the pawls or tongues will spring to positions to the rear of bead 54 l as shown in FIG. 11 and thus prevent a detachment of the hub and needle from the ampule.

The rear end of theampule 51 is closed by astopper 62. Similarly, to stopper 55-56, this stopper may be formed of natural or synthetic rubber. It has a diameter slightly less than that of the bore ofbody 51. Adjacent its forward end, it is provided with a sealing ring by forming it with anannular ridge 63 which in section may be rounded or V-shaped. The diameter of this ring is-in uncompressed conditi0n-slightly greater than the bore ofampule 51. The rear face ofstopper 62 is interrupted by slits 64 which when this Zone of the stopper is expanded, may be V-shaped. Its central portion is recessed as especially shown in FIG. ll. Betweenstoppers 55 and 62, a body ofmedicament 65 is confined within .ampule 51. Finally, with reference to the structure of this assembly, it will be noted that the outer zone of the needle extending beyondhub portion 59 is protected by an enclosing sheath 66 of plastic or other suitable material. The base of this sheath is expanded aroundhub portion 59 in sealing contact therewith to maintain the sterility of the needle.

This unit comes to the physician or ultimate user with theampule 51 filled withmedicament 65; the body of medicament being sealed against contact with the air by the Stoppers at the opposite ends. The rear portion ofstopper 62 extends slightly beyond the rear edge of ampule 51 (FIG. 8). The inner end ofneedle 58 is embedded withinstopper 55 and thus maintained in sterile condition. The user, by gripping sheath 66 adjacent thehub portion 59 is able to push that hub portion to a point wherepawls 61 override bead 54 and lock behind the same. With such movement of the parts, the inner needle end is caused to penetrate the diaphragm or remaining portion ofplug 55 so that this end is immersed within the medicament Aat a point immediately beyond the inner end ofstopper plug 55. With this movement of the parts, the flange interveninghub portions 59 and 60 will bear against the head 56 of the stopper and slightly compress the same. Therefore, that head will exert a slight tension on the hub assuring that the free ends of the pawls will remain in fixed engagement with the bead 54 or its equivalent. Simultaneously, the projectingportion 57 of the stopper will enter the interior ofhub part 59. Under these circumstances, it will be seen that the needle will be iirmly mounted against all undesired movements with respect to theampule 51. Before releasing the sheath 66, the operator may impart to the base portion of the same a slight twisting movement. This will free the inner face of the sheath fromhub portion 59 so that a subsequent pull on the sheath will unseat the latter.

In the embodiment under consideration, it will be observed thatpiston 46 is formed with agroove 68 adjacent its forward end. Secured to the forward face of casing 15 by abolt 70 is a catch plate 69 (FIGS. 1 and 2). The latter is shiftable transversely of the longitudinal axis of the apparatus, and with the removal of theinjection tube 16, will partially overlap the opening thus exposed. Therefore, ifpiston 46 is moved to a position where thegroove 68 is immediately in line with the forward face ofcasing 15, the catch may be swung around its pivot 7i) to enter that groove. Under these circumstances, the piston will be maintained in projected position.

By means of the present teachings, it is feasible to operate the apparatus so that only a portion of themedicament dosage 65 will be injected. For example, assuming thatampule 51 contains one cubic centimeter of the liquid, the parts may be related so that only onequarter, one-half, or three-quarters of a cubic centimeter will be discharged through the lumen ofneedle 58. Of course, if no adjustment or restraint is resorted to, then the entire charge of one cubic centimeter will be dispensed. To obtain this result, the following structure may be employed:

Piston 46 may be reduced adjacent its forward end to be encircled by asleeve 71. In turn encircling that sleeve is asecond sleeve 72. These provide an extension of the piston. The latter, as especially shown in FIG. 8, is conveniently formed with a series ofnotches 73 axially spaced from each other and connected by aslot 74. Adjacent thereto and in line with these notches aremarkings 75 which may, for example, read 1%1, 1/2, 5%1," and "1 cc. A pin orbolt 76 is carried bysleeve 71 and has a head of an area such that it may ride selectively into one of thenotches 73 through theslot 74. As will be understood, withpin 76 in the notch designated as l cc. and as shown in FIG. 8,sleeve 72 Will be retracted to a maximum extent. Depending upon thenotch 73, within whichbolt 76 is disposed to the rear of the first-named notch,sleeve 72 will be increasingly projected with respect to the body ofpiston 46 andsleeve 71. By exerting a pull onpiston 46, it may be projected to permitplate 69 to entergroove 68. Thereupon, the desired adjustment may be made, after which catch 69 will be released. With such release,piston 46, under the retracting influence exerted byspring 47, will be drawn back into the bore of body until the parts finally assume the positions shown in FIGS. 7 and 8. Before departing from a consideration of this particular structure, it will be observed as especially shown in FIGS. 8 and l2, that the forward end ofsleeve 72 extends materially beyond the adjacent end ofsleeve 71 and presents an inwardly taperedsurface 77 terminating in ashoulder 78 spaced from the edge ofsleeve 71.

Disposed for movement within theinjection tube 16 is anampule holder 79 in the form of a cylinder having slittedside portions 88.Spring arms 81 are secured adjacent their .forward ends to the inner face of theholder 79 and have inwardly bent portions which, due to the resiliency of these arms, extend into the bore of the holder. The rear ends ofarms 81 terminate in pawl orhook portions 82. The latter extends to the rear of theholder 79. When anampule 51 is Within that holder, the outer face of the former bears against the inner edge portions ofarms 81 and swings theportions 82 thereof outwardly so that they occupy a position spaced from each other a distance equal to the diameter ofshoulder 78.

Piston 46 is continued in the form of astem 83 of reduced diameter. That stem is encircled by the extension provided bycylinder 72. The end of the stem is bored. It receives apost 85 which mounts a collar 86 at a point short of its outer end. Beyond this collar, ahead portion 87 defines the forward end of the post. 'Ihis head portion is conveniently in the form of a truncated cone and conforms generally to the interior recess provided in the rear surface ofstopper 62 with the notches 64 in expanded condition. Thispost 85 provides an ampule plunger. It is secured to but has lost motion with respect to stem 83. To connect the parts, land as shown in FIGS. ll and l2, post l85 is formed with aslot 88. Apin 89 extends transversely through this slot and is mounted bystem 83.

The rear end of theampule holder 79 is reduced as at 90 to provide a sleeve (FIG. 13) portion slidably encirclingstem 83. This -sleeve is formed With aslot 91 through which the end ofpin 89 extends. Encircling sleeve portion '90 is asecond sleeve 92. The latter is conveniently formed with an outstanding and knurled ange '93 so that it may readily be gripped and turned by the lingers of an operator. By means of a pin andslot coupling 94, between these elements, relative rotation is limited,Sleeve 92 is formed with a U-shaped slot, onearm 95 of which terminates short offlange 93. The other arm. 196 extends throughflange 93 to the edge of thesleeve 92. Aspring 97 has one of its ends attached to the rear end ofsleeve 98. Its opposite end is secured tosleeve 92. This spring tends to maintainarm 96 of the slot in registry with theslot 91 ofsleeve 90 so thatpin 89 may ride Within these slots. However, withpin 89 disposed adjacent the base of the U-shaped slot,sleeve 92 may be turned against the resistance ofspring 97 so as to registerpin 89 witharm 95 in the manner shown in FIG. 13 where that pin is illustrated adjacent the end of such arm.

The windows orsight openings 18 are normally obstructed by aring 98 which is slidably mounted within the bore ofinjection tube 16, as in FIG. ll. -This ring is provided adjacent its inner end with aflange 99 which defines a diameter greater than that ofhub portion 68 but less than the maximum diameter ofampule 51. Aspring 100 is interposed between this ange and the forward end oftube 16, and thus maintainsring 98 in the position shown in FIG. 7 unless it is deliberately shifted.Tube 16 is provided with anopening 101. A spring arm 182 has its rear end secured to the base oftube 16 and extends adjacent the outer surface of that unit. At its opposite end, a pawl or latch 103 is affixed .tot this arm and projects throughopening 101 into the bore of thetube 16.

In using the apparatus,cap 19 is removed. Aflask 36 is introduced into the exposed bore so that the diaphragm portion at the outer end of tip 37 is adjacent the point of valve 38. That valve, by its actuator 2t), should be shifted to fully projected or closed position. Withcap 19 reapplied to its threads and tightened to fully seated position, it will causeflask 36 to be projected so that point or Valve 38 will penetrate the diaphragm of its tip. Conveniently at this time, dial 31 is shifted to a position where its Zero indicia mark is in registry withline 35. During this operation, the safety provided byplate 23 or functionally equivalent structure will, of course, be maintained in a position where the trigger or actuator of the assembly may not be shifted.

Tube 16 is now removed to expose theampule carrier 79. An ampule-needle assembly as shown in FIG. 8 is introduced into the carrier so that the rear edge oftube 51 bears against the shoulder intervening thecarrier 79 and its reducedportion 90. Under these circumstances,head 87 will bear in engagement with the surfaces of the cavity in the rear face ofstopper 62. Therefore, the rear part of this piston stopper will be expanded as shown in FIG. 8. After the introduction of the ampule into the holder, the user will shift hub 60 rearwardly with respect toneck portion 53. This wil-l result in a locking of the needle assembly against removal or substantial movement with respect to the ampule body and will also cause the inner end of the needle to penetrate the diaphragm portion ofstopper plug 55. At this time, sheath 66 may be turned with respect tohub portion 59 so as to free it for subsequent complete removal.

It will be assumed that the full dosage of themedicament body 65 is to be injected. Also, it Will be assumed that an aspirating action is to be achieved. In the latter connection, it will be necessary to elect relative movements of sleeves and 92 so thatpin 89 will lie Within the leg of the U-shaped slot in the latter sleeve. It is to be noted, regardless of the type of injection which is to be given, that with the complete introduction of theampule body 51 into thecarrier 79, the rear edge of the for-mer will bear againstarms 81 to swing their catch or pawl-shaped ends 82 outwardly. Therefore, ascarrier 79 abuts sleeve 72 (see FIG. ll), thepawls 82 will interlock withshoulder 78 to couple the parts.Tube 16 is now again mounted onbody 15 and the parts will be disposed in the positions shown in FIG. 7, taken in con junction with FIG. l1, after sheath 66 is Withdrawn through the outer opening ofnose portion 17.

The site of injection having been selected the safety provided byplate 23 will have been shifted.Nose piece 17 will be brought into iirm contact with the epidermis at the desired zone. Prior to this, valve actuator 28' will have been turned so as to retract the point of `the valve from the end of tip 37 and to unseat the plug portion 38 of its body from the adjacent cavity surface. Accordingly, if liquid Freon is used within flask orcylinder 36, that material will convert to gas under pressure and flow through passage 39 into the bore 40. Within that bore it will act with equal force upon both of the rings orpackings 49 associated with stem 41 at points to opposite sides of the exit end of passage 39. Therefore, an operator will merely have to overcome the force of `spring 42 to projectactuator 21.

With such projection, communication will be established between passages 39 and 43. Therefore, fluid under pressure Will flow throughbore 44 intocylinder 45 and actyagainst piston 46. That piston will now be rapidly projected. With such projection,needle 58 will plunge into the tissues to the desired depth which will correspond to the length of the needle exposed `beyondnose portion 17 after hub portion 60 has engaged the restricted end oftube 16. Coincident with this projection,ring 98 will be projected against the action of spring S to move `beyondopening 18. Also, catch 103 will have latched against the rear edge ofcarrier 79 to prevent its retraction.

It is of course understood that in this stroke, the coupling between thecarrier 79 andpiston 46 is furnished incident to pin S9 bearing against the forward end ofarm 95 of the U-shaped slot. The parts will remain in this fully projected position as long as theactuator head 21 is maintained in depressed condition. Upon the release of this actuator, the fluid under pressure withincylinder 45 and bore 44 will be free to drop to yatmospheric pressure because the packing 49 adjacent the forward end of stem 41 will have moved to the rear of passage 43 as shown in FIG. 7. Under these circumstances, the compressed fluid may escape through the vent opening provided at the forward end ofbore 46.

When this occurs,spring 47 will retractpin 89 until that pin bottoms inslot 88. Thereupon, post 85 will retract thereby retractingpiston 62. As a result of this functioning, it is obvious that if the needle be closed by tissues preventing aspiration, the apparatus will still function becausesleeve 92 will rotate in any event `during this phase of the operative cycle. Therefore, that cycle may `be continued through to termination even with the lumen of the needle blocked. Normally, however, with the rearward movement ofstopper 62, suction will be exerted through the lumen ofneedle 58. I-f the outer point of that needle be lodged in a vein, then this will be evident by blood flowing from the inner end -of the needle.ampule 51 is transparent andopenings 18 are unobstructed. Therefore, by looking through the latter, an observer will be able to determine whether blood is being discharged by the inner needle end.

As will `be apparent, the retraction ofpiston 46 byspring 47 will be limited to the length of travel ofpin 89 withinarm 95 of the slot insleeve 92. Aspin 89 reaches a point adjacent the base of the slot,sleeve 92 will rotate aroundsleeve 90 under the influence ofspring 97. With such rotation, the pin will be aligned withleg 96 of the U-shaped slot. Therefore, if `actuator 21 is now again thrust inwardly, fluid under pressure will projectpiston 46. No obstruction to its movement will exist becausepin 89 is now riding within `slots 96 and 91. The ampule is incapable of further forward movement with respect totube 16. Accordingly,head 87 will shiftpiston stopper 62 forwardly through the bore of the ampule. In such shifting, a substantially complete expulsion ofmedicament 65 will yfollow because of the seal provided byrib 63 and the secondary seal furnished by the trailing edge zone ofstopper 62 incident to expansion by thehead 87.

It will be understood that with the cycle of operation continuing, the coupling furnished by parts 81-82 and 77-78 will lbecome effective. Under these circum- Such flow will be visible because the body of f stances,carrier 79 will abutsleeve 72. As these parts move adjacent latch or catch 103, that pawl will be cammed outwardly, thus rendering it inoperative to restrain a subsequent retraction of the assembly.

With the projection of stopper orpiston 62, the entire liquid content ofampule 51 will be injected into the patient. The piston stopper will be arrested in a zoneadjacent shoulder 52 of the ampule. Thereupon, when the operator releasesactuator 21, it will return to its initial position under the influence of spring 42. Accordingly, the fluid under pressure will again escape through the vent in ybore `40.Spring 47 will retract the piston. Incident `to the coupling afforded bylatch portions 82 againstshoulder 78, this retraction will result in thecarrier 79 and the ampule-needle assembly being retracted to thereby withdraw the needle from the tissue.Tube 16 may now be dismounted and the ampule withdrawn from the carrier. This will result in the detachment ofstopper 62 fromhead 87; it being noted that as soon as the stopper reaches a position where its rear zone is beyond the `ampule 51, a ready separation of the parts will occur especially in view of the slits or notches 64 incorporated in the stopper as shown in FIG. 8. With such separation, the ampule may be withdrawn `fromcarrier 79. This Will release pawls S2 to allow of withdrawal of the carrier.

The spent ampule may be replaced by a fresh ampuleneedle assembly. Prior to that,plate 23 will have been shifted to a position where it has entered notch 22 to prevent an operation of the triggering mechanism. AS will be evident, eachtime plate 23 is shifted, dial 3i will be indexed. This will enable the operator to determine the number of charges remaining within the capacity offlask 36. Accordingly, there will be no danger of failure to operate incident to the exhaustion of the source of fluid under pressure.

As is apparent, if no aspirating action is desired, thensleeve 92 will not be manually rotated to bringpin 89 withinleg 91. Rather, that pin will be permitted to rest withinleg 96. Under those circumstances, an actuation oftrigger 21 will result in a bodily projection ofarnpule 51 and itsneedle 53 as heretofore described. However, upon the ampule reaching a position adjacent the outer end oftube 16, the pressure on piston-stopper 62 will continue and that piston will project through the bore oflampule 51. Upon releasingactuator 21, the entire ampule and needle will be retracted into the lbody oftube 16.

Thus, among others, the several objects of the invention as specifically aforenoted are achieved. Obviously, numerous changes and rearrangements of the parts might be resorted to without departing from the spirit of the invention as defined by the claims.

I claim:

l. A hypodermic injection apparatus including in combination a casing formed with a bore having an open outer end and an opposite end furnishing a cylinder, a source of fluid pressure, said casing providing a passage extending from said cylinder to said source, a valve movable to control the flow of fluid through said passage to said cylinder and to vent fluid from the latter, a piston slidable within said cylinder, a pin shiftable with said piston, a carrier slidable within the outer end Zone of the bore, said carrier supporting an ampule carrying a hypodermic needle at one end and having at its opposite end a stopper projectible through its bore to expel medicament through the lumen of the needle, means connecting lsaid pin with said carrier to slide the latter towards the open end of said bore as said piston is projected, means secured to said casing to arrest movement of said carrier upon the latter reaching a position adjacent said open end, means for preventing a withdrawal of said carrier from such position, a stern forming a part of said piston to couple the latter with the stopper of said ampule, means for rctracting said piston to correspondingly move the stopper connected to said stem and to cause an aspirating action within said ampule, and said stem being Isubsequently again projectible towards said open end to cause the ampule stopper to be projected through the ampule bore.

2. In an apparatus as delined in claim 1, the means connecting said pin and carrier, including an axially extending slot formed in said carrier and within which said pin is disposed to engage the slot base upon said piston being projected towards the outer end of said bore, and means functioning upon said piston retracting to remove said pin from within said slot.

3. In an apparatus as defined in claim 2, said piston retracting means comprising a spring connected to said piston and casing respectively, and said pin and slot providing for lost motion on the part of said carrier with respect to said piston upon the latter reti-acting.

4. In an apparatus as defined in claim 2, a sleeve encircling a part of said carrier, said sleeve being iformed with a further slot communicating with said first-named slot and providing during projection of said piston substantially no obstruction to movement of said pin, and a spring cooperating with said sleeve to move the latter and shift said pin from said first-named to said lastnamed slot.

5. In an apparatus as dened in claim 2, and means forming a part of said piston whereby the eiective length of the latter may be varied to correspondingly vary the working stroke of said piston.

6. In an apparatus as dened in claim 4, said piston being formed with a bore, one end of said spring being connected to the end of said bore and said spring extend ing through the latter and being connected to the casing adjacent the end surface defining said cylinder.

7. A hypodermic injection apparatus including in combination a casing formed with a bore having an open outer end and an opposite end furnishing a cylinder, a source of luid pressure, said casing providing a passage extending from said cylinder to said source, a valve movable to control the ow of fluid through said passage to said cylinder and to vent fluid from the latter, a piston slidable within said cylinder, an ampule carrier slidable within said bore and connected to move with said piston, means at the open outer end of the casing preventing an ampule supported by said carrier from being projected therethrough, a sleeve, a detachable coupling for normally securing said sleeve against movement with respect to said carrier, said coupling embracing a plurality of engageable parts mounted by said carrier and sleeve and means functioning upon an ampule being removed from Said carrier to shift said parts out of engagement and render said coupling inoperative.

8. In an apparatus as defined inclaim 7, said coupling comprising an arm mounted by said carrier, a catch coupled to said arm, a surface of said sleeve providing a keeper for said catch and said arm being shiftable, upon an ampule being removed from said carrier, to release said catch from said keeper.

References Cited in the iile of this patent UNITED STATES PATENTS 1,845,036 Busher Feb. 16, 1932 2,445,477 Folkman July 20, 1948 2,472,116Maynes lune 7, 1949 2,505,765 Grau May 2, 1950 2,605,765 Kollsman Aug. 5, 1952 2,605,766 Uytenbogaart Aug. 5, 1952 2,645,223 Lawshe et al July 14, 1953 2,679,843 May June l, 1954 2,693,183 Lockhart Nov. 2, 1954 2,752,918 Uytenbogaart July 3, 1956 2,766,755 Greene Oct. 16, 1956 FOREIGN PATENTS 505,931 France May 17, 1920

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