US2635601A - Injection device - Google Patents

Description

E. A. MAY

INJECTION DEVICE Filed NOV. 15, 1951 April l21, 1953 Patented Apr. 21, 1953 INJECTION DEVICE Edwin A. May, Glen Rock, N. J., assgnor to Becton Dickinson and Company, Rutherford, N. J., a corporation of New Jersey Application November 15, 1951, Serial No. 256,499

This invention relates to an improved injection device for administering medicaments hypodermically without the use of a skin-piercing needle. y

It is an object of the invention to provide an apparatus which may be caused to readily perform a complete cycle of operation and in which the resultant injection will be of a desirable character. K

A further object is that of furnishing a mechanism which will be of relatively small size and light weight; the device embodying relatively few parts, each individually simple and rugged and capable of ready assemblage to furnish a unit having a long effective life.

Reference is had to the attached sheet of drawings illustrating embodiments of the invention in which: Y

Fig. 1 is a sectional side view of the device;

Fig. 2 is a section taken along the line 2-2 in the direction of the arrows as indicated in Fig. 1;

Fig. 3 is an enlarged transverse sectional view taken along the line 3--3 in the direction of the arrows as also indicated in Fig. l;

Fig. 4 is a sectional view of the loading assembly; and

Fig. '5 is a fragmentary sectional view of an alternative structure.

Referring primarily to Fig. 1, it will be seen that the numeral 5 indicates the body or barrel of the device to which a nose piece or extension 6 is secured as, for example, by screw threads. To the forward end of this extension a loading cap may be attached again by screw threads, if desired. Extension 6 and loading cap 'I are provided with internal bores defining a medicament receivingV chamber. Rather than having a uid medicament disposed in direct contact with the wall of the chamber, that medicament is preferably contained in an ampule or receptacle. Such ampule may take one of numerous different forms including, for example, a rubber sack which is invertible upon itself and which is provided adjacent its forward end with an orifice-defining member. In the drawings the ampule has been illustrated as embracing a tubular body preferably formed of glass. This is to be taken in an illustrative rather than a limiting sense.

Thus, while in all instances it is preferred to have the enlarged bores defining the medicament chamber lined with displaceable material, such yas rubber sleeves 8 and 9 secured against movement with respect tothe extension and loading cap by, for example, annular ribs I0, a

8 Claims. (Cl. 12S-173) glass ampule in the form of a tube II has been shown in this gure. That ampule has adjacent its rear end a stopper I2 of the piston type. Adjacent its forward or outer end it is provided with a perforable stopper I3. Between these Stoppers the medicament to be injected is disposed. A nozzle I4 extends through a central aperture in the outer face of the loading cap 'I. This nozzle is conveniently formed with a base portion I5 having a diameter substantially equal to the head of stopper I3. The nozzle has an orice I6 adjacent its outer end and the diameter of that nozzle is relatively fine, Vpreferably being within the range of from .003 to .012. The nozzle also conveniently mounts an inwardly extending pointed cannula I'l of a length adequate to pierce stopper I3 and establish communication with the interior of the ampule.

In order to eject the medicament from the chamber dened by extension 6 and loading cap 1, a plunger I8 is projectible through a bore of proper size in the former. This plunger has secured to it an extension I9 conveniently formed of rubber. Extension I9 has a diameter such that it may enter the bore of tube I I. While this extension may be secured to plunger I8 in any desired manner, it is preferred to employ a bolt 20 the threads of which engage corresponding threads in a bore formed in the outer end of the plunger. This bolt is provided with a headed portion keying into a correspondingly contoured recess formed in the rear end of extension I9 to retain the latter for reciprocation in the plunger.

It is apparent that with a lled ampule disposed in the medicament chamber if plunger I8 is projected with sufficient force, A`extension I9 will be caused to exert pressure on stopper I2 such that the latter will be moved through the bore of tube II. At this time it will be noted that the length of the medicament chamber is such that the rear edge of tube II is preferably spaced from the rear end of that chamber. Accordingly the adjacent portions of sleeve 8 will intervene these parts. Therefore, extension I9 will contact these end portions of sleeve 8.

Under the forces employed, extension I9, upon being projected, will tend to displace into the rear end of the medicament chamber. Therefore it will engage the rear end portions of sleeve 8 and tend to displace the material of the latter. This force will also act through sleeve 8 upon sleeve 9; pressing against the rear end edge of the same. Under these forces both sleeves 8 and 9 will tend to constrict to thus reduce the bore of the medicament chamber. With such action they will move into intimate supporting 3 relationship with the outer face of the ampule tube Il. Therefore they will support that tube against internal bursting pressures. A construction of this type is especially desirable where the ampule is formed of glass or similarly frangible material. Regardless of this cooperation of the parts, it will be understood that with the forward projection of piston l2 medicament will be ejected through the bore of cannula il and orifice l5. The ejection occurring under suicient pressures and the end of the nozzle being in con- Y tact with or adjacent the skin at a point overlying the area to be injected, it follows that the stream oi' medicament will pass through the epidermis and lodge into the underlying tissues.

Now with a view to producing a force adequate to cause movement of the plunger I8 inthe man:Y

ner desired, it will be noted that this plunger' preferably terminates in a base portion 2l. This base is secured, for example, by screw threads to the forward end of an actuating tube 2,2 slidably disposed within casing 5. Conveniently a packing member in the form of an O-ring 22' may be disposed adjacent the point of juncture of base 2l and tube 22. The interior of that tube serves as a pressure accumulator chamber in a manner hereinafter described and with huid under pressure within its bore it is apparent that packing 22 will serve to prevent anescapeof gas from the forward end of the tube. A shock absorbing unit for example in the form of a ring of resilient material as indicated at 23 may be mounted to extend beyond the rear face of nose piece G. In such position it will be capable of being engaged by the forward end of tube 22 and/or base 2l to prevent damaging contact between these parts.

Casing supports a housing 24. It is provided with an enlarged portion within which there is rotatably mounted a pinion 25. The teeth of the latter mesh with the teeth of a rack 25 secured against movement With respect to and extending from the outer face of tube 22. The shaft of the pinion mounts adjacent one of its ends a socket portion 2l engageable with the faces of a wrench which may be of the ratchet type and by means of which pinion 25 may be turned. The opposite end of this shaft is conveniently retained in position by being grooved and having extending into this portion a key 28 immovably mounted with respect to the side wall or housing 24. A pawl 29 has its operative end engaging the teeth of pinion 25. It is pivotally supported as at 32 adjacent its opposite end from the side walls of the housing 26%. A spring 3| cooperates with the inner face of the housing and the pawl to normally assure an engagement of the pawl with the pinion teeth. To permit of a disengagement of these parts a semi-circular shaft 32 may extend across housing 24 immediately below pawl 29 and have secured to it; a crank or lever 33. When the latter is in the position shown in Fig. l, the end of pawl 29 will co-act with the surfaces of the pinion teeth. When lever 33 is pressed downwardly, then its shaft 32 will act as a cam to shift pawl 29 upwardly to a point where it clears the teeth of the pinion.

A closure plug is mounted against movement within the rear end of casing 5. This plug has been indicated by the reference numeral 34. It serves to support a stem 35 which extends axially of the bore of the casing and within the latter.

A bushing 36 encircles stem 35 and is formed with grooves in its inner and outer faces to receive suitable packings preferably in the form of o-rings 3l as in Fig. 1. This bushing is Drevented from moving inwardly with respect to tube 22 by abutting a shoulder portion 38 forming a part of the latter. With its associated packing it functions as a piston in cooperation with the exterior surfaces of the stem 35.

Plug 34 is conveniently formed with a central aperture normally closed by a cap 39. Inwardly of this cap the stern 35 is formed with a bore 4l which is normally maintained in closed position by a preferably metallic sealing member 4G. A rearward displacement of bushing 36 with respect to tube 22 is prevented by a ring 42 preferably having screw threaded engagement with the tube. y

As afore brought out, tube 22, in addition to functioning as an actuator for plunger I8 serves as Ya pressure accumulator. To this end its interior, as well as the bore of stem 35 may be charged with fluid under suitable pressures. Conveniently the uid may be nitrogen and the pressures employed be in the range of from 1,200 to 1,550 pounds ofV pressure to the square inch. Pressures of this value willV impart to the medica ment an injection pressure of from around 3,600 pounds to the square inch to 4,600 pounds to the square inch. A charging of the tube may be eifected by removing closures 39 and 40 and connecting bore 4| with a source of gas under pressure.

This step has been illustrated in Fig. 4 in which 43 indicates a fitting connected with a source of gas under pressure and conveniently provided with a relief valve 44. This fitting has an extension 44 threaded to engage with plug 34 and mounts a sealing screw 45 carrying a wrench part 46 to manipulate member 40. O-rings 41 prevent leakage. Accordingly, the interior of the tube may have a pressure charge of, for example, the value indicated. Thereafter, cap 39 may again be mounted in position.

If lever 33 is now shifted so that the end of pawl 29 may engage the teeth of pinion 25, it is apparent that a wrench or handle of suitable type may be coupled to the shaft of the pinion in order to rotate the latter in a clockwise direction as viewed in Fig. 1. Such rotation of the pinion will cause rack 26 to be retracted. In View of the fact that the latter is fixed with respect to tube 22 that tube will also be retracted. In such retraction it will carry with it the bushing 36. Accordingly the latter will slide over the exterior surface of stem 25. Therefore, the stem will project increasingly into the bore of tube 22 to accordingly reduce the interior Capacity of the accumulator. This will serve to increase the value of the charge or pressure which is within the bore of that structure. The teeth of pinion 25 will be engaged by pawl 29 to prevent the parts from projecting.

The foregoing action will continue until tube 22 is moved to a position at which the foremost of the teeth of rack 2G is adjacent pinion 25. At that time loading cap i may be removed and an ampule inserted into the medicament chamber after which the loading cap is remounted upon extension 6 and the parts are in the position shownl in Fig. 1. Of course if a spent or discharged ampule has heretofore been in position within the medicament chamber that ampule is removed before the fresh ampule is inserted in the manner described. In any event the device is now rea-dy to inject tissues.

The locale of injection having been determined, nozzle I4 is brought into contact with the epi--v dermis overlying this area or else is slightly adattati spaced from that surface. Lever `33 is now shifted. This will cause the cam provided by the shaft section 32 to swing pawl 29 upwardly against the action of spring 3l to a point where it clears the teeth of pinion 25. As such clearance occurs the pinion is released for rotation. The base of the bore of stem 35 serves as a reaction point adjacent one end of the assembly for the gas under pressure. The opposite end of tube 22 serves as a second reaction point. Therefore that tube together with its plunger I8 will be forcibly projected in order to achieve the desired expulsion of medicament. Thereafter the described cycle of operation may be repeated.

As will be obvious bushing 36 could be eliminated. This has been shown in Fig. 5. In that View stem 43 is of heavier gauge than the stem 35 in Fig. 1. Tube 4S lies immediately adjacent and encircles it. Stem 48 may -be formed with a groove adjacent its outer end to receive a packing such as an O-ring. Thus an extra packing as well as the bushing may be ydispensed with. A covering 5| may be applied over the loading cap. This covering being of rubber or similar material will prevent chilling contact with the patients skin.

It will be understood that with a structure of this nature the packings are always under pressure. Therefore leakage will be reduced to a minimum, if not entirely eliminated. The device may be easily loaded, cocked and fired. Either glass ampules or other medicament-containing units may be employed. The depth of penetration may largely be controlled by having the orice I6 of suitable diameter. The parts are so proportioned that with an ampule in position, substantially all medicament will be expelled therefrom during the power stroke. If no ampule is in place, then the forward face of base portion 2| will engage the shock absorbing Y bumper 23 on this stroke.

Thus, among others, the several objects of the invention as specifically afore noted are achieved. Obviously numerous 'changes in construction and rearrangements of the parts might be resorted to without departing from the present teachings as defined by the claims.

I claim:

1. A hyp-odermic injection device including in combination a hollow body presenting a medicament chamber adjacent its outer end, a tube slidable within said body and provided with a substantially unobstructed bore, means projectible with said tube and disposed adjacent one of Ithe ends thereof to cooperate with said chamber and expel medicament therefrom, movable means mounted by said body and connected with said tube to retract the latter, a stem mounted adjacent the inner end of said body and said stem extending into the bore of said tube to provide a reaction member for gas under compression within the bore of the same.

2. A hypodermic injection device including in combination a hollow body presenting a medicament chamber adjacent its outer end, a tube slidable within said body and provided with a substantially unobstructed bore, means projectible with said tube and disposed adjacent one of the ends thereof to cooperate with said chamber and expel medicament therefrom, movable means mounted by said body and connected with said tube to retract the latter, a stem mounted adjacent the inner end of said body and extending into the bore of said tube to provide a reaction member for gas under compression within 6 the bore of the same and a bushing interposed between said stem and tube bore to prevent an escape of such gas.

3. A hypodermic injection device including in combination a hollow body presenting a medicament chamber adjacent its outer end, a tube slidable within said body and provided with a substantially unobstructed bore, means projectible with said tube and disposed adjacent one of the ends thereof to cooperate with said chamber and expel medicament therefrom, movable means mounted by said body and connected With said tube to retract the latter, a stem mounted adjacent the inner end of said body and a bushing carried by and movable with said tube, said bushing being interposed between said stem and tube bore to prevent an escape of such gas.

4. A hypodermic injection device including in combination a hollow body presenting a medicament chamber adjacent its outer end, a tube slidable within said body and provided with a substantially unobstructed bore, means projectible with said tube and disposed adjacent one of the ends thereof to cooperate with said chamber and expel medicament therefrom, movable means mounted by said body and connected with said tube to retract the latter, a stem mounted adjacent the inner end of said body and said stem being provided with a passage through which access may be had to the space dened by said bore.

5. A hypodermic injection device including in combination a hollow body presenting a medicament chamber adjacent its outer end, a tube slidable within said body and provided with a substantially unobstructed bore, means projectible with said tube and disposed adjacent one of the ends thereof to cooperate with said chamber and expel medicament therefrom, movable means mounted by said body and connected with said tube to retract the latter, a stem mounted adjacent the inner end of said body, said stem being provided with a pass-age through which access may be had to the space defined by said tube bore and a penetratable plug disposed within said passage.

6. A hypodermic injection device including in combination a hollow body presenting a medicament chamber adjacent its outer end, a tube slidable within said body and provided with a substantially unobstructed bore, means projectible with said tube and disposed adjacent one of the ends thereof to cooperate with said chamber and expel medicament therefrom, movable means mounted by said body and connected with said tube to retract the latter,I a stem mounted adjacent the inner end of said body, said stem being provided with a passage through which access may be had to the space dened by said tube bore and a cap carried by said body in line with the passage of said stem.

7. A hypodermic injection device including in combination a hollow body presenting a medicament chamber adjacent its outer end, a tube slidable within said body and provided with a substantially unobstructed bore, means projectible with said tube and disposed adjacent one of the ends thereof to cooperate with said chamber and expel medicament therefrom, movable means mounted by said body and connected with said tube to retract the latter, a stem mounted adjacent the inner end of said body and extending into the bore of said tube to provide a reaction member for gas under compression within the bore of the same, a bushing interposed be- 7 tween said stem and tube bore to prevent an escape of such gas and releasable means for maintaining said tube in retracted position.

8. A. hypodermio injection device including in combination a hollow body presenting a medicament chamber adjacent its outer end, a tube slidable within said body and provided with a substantially unobstructed bore, means projectible with said tube and disposed adjacent one of the ends thereof to cooperate with said chamber and expel medicament therefrom, a pinion rotatably mounted by said body, a rack carried by said tube and extending beyond the outer face of the same to engage the teeth of said pinion whereby the latter may retract said rack and tube, a stem mounted adjacent the inner end of said body and said stem extending into the bore of said tube to provide a reaction member for gas under compression within the bore of the same.

EDWIN A. MAY..

No references cited.`

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