US2940446A - Hypodermic assembly - Google Patents

Description

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9. 2,940,446 HYPODERMIC ASSEMBLY George N. Hem, In, San Carlos, Califi, assignor to Becton, Dickinson and Company, Rutherford, NJ., a corporation of New Jersey Filed Feb. 26, 1958, Ser. No. 717,718 16 Claims. (Cl. 128-218) This invention relates to a structurally and functionally improved medicament injection assembly.

It is a primary object of the invention to furnish an assembly which may be effectively used for hypodermic self-injection by an unskilled person who, in fact, may be handicapped by injury or shock.

A further object is that of furnishing a mechanism the parts of which may readily be cleaned, sterilized, filled and loaded. When in this condition the operating parts will be maintained against contamination. Moreover, even if the unit is carelessly carried or stored, foreign materials will not enter it so that its functioning will be impaired.

An additional object is that of providing a hypodermic injection unit which will be automatic in nature, but in which, unless the parts are deliberately manipulated, there will be no danger of accidental firing or medicament-discharge occurring. Therefore, the unit may be subjected to shocks and other abuse wthout impairing its functioning. At the same time, the present invention furnishes a mechanism in which, by means of the simplest sequence of operations, the device may be fired with assurance that a proper injection is achieved, even although this may be efiected through layers of clothing or covering.

Still another object is that of providing an assembly which will include relatively few components, each individually simple and rugged in construction, such components being capable of ready assembly, and when so assembled furnishing a unitary structure capable of being stored or carried for indefinite periods of time without affecting the working of the apparatus.

Still another object is that of furnishing a mechanism of improved function and design for restraining the projection of a hypodermic needle and for releasing the needle for projection.

With these and other objects in mind, reference is bad to the attached sheet of drawings illustrating practical embodiments of the invention, and in which:

Fig. l is a sectional side view of an improved hypodermic assembly;

Fig. 2 is a fragmentary sectional view in enlarged scale, showing the details of the mechanism for restraining or preventing the projection of the hypodermic assembly;

Fig. 3 is a view similar to Fig. 2 but showing the parts shifted to a different position, in which the restraint thereon is released; and

Fig. 4 is again a view similar to Fig. 2, but illustrating a slightly different form of mechanism.

Referring primarily to Fig. 1, the numeral indicates a casing which in certain assemblies is preferably formed of stainless steel, and under other conditions may be formed of different materials. In view of the fact that the illustrated assembly is of the power type, it is preferred to employ a spring to efiect projection of the hypodermic needle and expulsion of the medicament through the lumen thereof. Such a spring has been shown at 11, and has its rear end conveniently bearing against a sealing disk 12 mounted by the adjacent end of casing 10. The forward end of the spring bears against a preferably cupshaped member 13 the base portion of which may be generally conical. In many respects it is preferred to em ploy a spring as the source of motive power. However, it will be apparent that other sources may be utilized.

2 atent If the casing 19 itself provides the ampule for the medicament, then that casing should conveniently be formed of stainless steel. In the event that a separate ampule of glass or other material is disposed within casing 10, then, of course, the latter may be formed of other materials, since its surface will not be directly exposed to the medicament. In the illustrated embodiment the ampule portion of the assembly has been shown as embraced within and forming a part of the forward end of casing 10, which therefore should be made of stainless steel or other suitable material with which the contained medicament will not react.

The rear end of the ampule compartment is defined by a plunger-type stopper 15. The forward end of the same embraces a similar stopper 16. Both of these elements may be formed of rubber or equivalent material. They are spaced along the bore of casing 10 a distance such as to define between them a chamber having a capacitywhen filled-equal to the desired body of medicament 17. Both stoppers 15 and 16 are formed with bores through which the body of a cannula 18 extends. Adjacent its forward end the cannula is provided with the usual beveled tissue-piercing point positioned beyond stopper 16. The rear end of the needle extends beyond stopper 15 and supports a mounting 19 having a conical rear end of less diameter than the bore of the cup-shaped member 13. The angularity of this face of the mounting is also greater than the angularity of the base surfaces of the cup, so that the former may rotate within the latter while the surfaces are in engagement with each other.

It is to be observed that the rear end of the needle 13, together with its mounting 19, is spaced Well rearwardly of the piston-stopper 15. Also, it is provided with an opening 21) communicating with its lumen within that zone. Such opening is preferably simply formed through the side wall of the cannula. The point of the needle, in its initial or normal position, preferably extends beyond the front end of the casing. That front end is defined by a disk 21 conveniently bearing against an adjacent shoulder portion of the casing and with the latter rolled over to retain it, in a manner similar to the retention of disk 12.

The disk 21 or its equivalent supports the forward stopper 16 against movement in an outward direction. It also furnishes a mounting for a neck in the form of a tube 22. That tube has a bore of such size that it slidably accommodates the needle 18. As in Figs. 2 and 3, the coupling between disk 21 and tube 22 is preferably effected by screw threads 23. The forward end of the needle is preferably conventional, and as such embraces a piercing point 24 to the rear of which a beveled surface 25 is provided and which defines the exit or discharge end of the lumen. The forward end of the tube 22 conveniently terminates in a head portion 26. The latter presents in its face a groove 27 suitable for the reception of the end of a screwdriver, by means of which tube 22 may be turned to secure it to or disconnect it from the mounting 21.

Slidably supported upon the tube or neck 22 is a trigger collar including a cup-shaped main body portion 28 and a base 29 which is bored as at St to permit of the passage ['of stube 2. It is to be noted that this bore has its face tapered or inclined. Immediately to the rear of head 26, tube 22 is formed with a recess in the form of a bore 32 xtending at an incline to both the axis of the tube. and a plane perpendicular thereto. It has been found that the inclination should preferably be around 25 from this plane, or in other words, with respect, to the tube axis.

The inclination of the wall defining the bore surface 3.0 should be around 6 with respect to this axis. Under relative imovement.

the form of a separate disk or defined by the outer end ,ofcasing 10.may include an outwardly flared flange these circumstances and with the trigger collar disposed in the position shown in Fig. 2, a detent in the form of a sphere 31 may bear against surface 30 as well as the forward surface of bore 32. Additionally, this detent will bear against the beveled surface 25 at the forward end of the needle and will extend partially into the lumen thereof adjacent the heel portion of the needle. The diameter of the sphere being sufiiciently large and the sphere being restrained from outward movement by surface 30, it follows that this detent will prevent a projection of the V needle 18.

Theneedle would, of course, normally project incident to the spring 11 or other power mechanism employed.

veniently include a somewhat conical base portion 39, rather than a cup-shaped base 29. In any event, as it is shifted rearwardly over the tube to a point where it clears the detent or sphere 31, ample space is present to receive the latter in a position at which it lies wholly to one side of'the needle 18.

. ,It is preferred that the collar'in every instance be pro- -tected,.not, alone to prevent contamination of the parts, but also to preclude an accidental triggering of thesame.

'With this in mind, and as in Fig.1; a safety cap 39' may enclose and extend beyond the forward end of the assembly. That cap can be formed of a plastic, such as polyethylene, or metal. Its skirt portion may include inwardly Such mechanism is thrusting on the needle body, due to the T I latter being slidably supported by stoppers 15 and 16 and having its rear end supported by the cup 13. The reason for having bore 32 inclined will now be apparent, in that the beveled surface 25, under the action of the power mechanism, functions as a wedge to shift detent 31 outwardly. In fact, ordinarily, and due to the pressures created, the sphere 31 will indent the heel portion of the needle to a sufficient extent so that core cutting isnot to be feared. The thrust of the detent in an outward direction is nicely proportioned and properly related to thesur- 2 and the position shown in full in Fig. 3 to that in- 'dicated in dotted lines in the latter figure. Under these circumstances, the movement of the needle 18 will no longer be obstructed. Accordingly, it will initially move I to theposition also indicated in dotted lines in Fig. 3.

. As a consequence of this movement, air between piston 15 and cup 13- will flow past the edges of the latter as the forward end of the needle moves outwardly of tube 22. The trigger collar 28 will of course be shifted rearwardly' incident to contact with the epidermis or with clothing overlying the same. Substantially instantaneously with the point of the needle having pierced'the epidermis and the lumen of the latter having been closed by tissue, opening 20 will be" sealed by passing through the bore of stopper 15. Therefore, no air will flow through the needle lumen.

opening 20 in advance of the forward face of stopper 15,

' medicament 17 will flow through that'opening into and extending ribs or projections seating similar recesses in the exterior face of casing 10. In this mannier the cap will be secured against accidental detachment. It will be'apparent that 'with the cap in. position, even a mishandling or dropping of the unit will not result in the collar 28 or 38 being moved rearwardly over the neck or tube 22 or 33. To further maintain the surfaces of the collars against soiling, and asshown in Fig. l as well as in Fig. 4, a cup 41' of rubber or similar material may be ensleeved over the collar. The base zone of this cup'may be engaged and retainedby a spring. ring 42.

In the assembly illustrated in Fig. 4, the ring may overlie the cup in the zone of flange so as to retain unit 41 ensleeved over the forward parts of the assembly,

Assuming that no separate ampule is employed, so that the interior of casing 10 actually provides the wall for the medicament-receiving chamber, then it will be under-' stood that the casing, including this wall surface and the a several other elements of the assembly are sterilized. This Under continued movement of the parts, cup member 13 will engage the rear face of stopper 15 and project the latter to function as a piston. With.

through the lumen of the needle and be discharged be yond the point of the latter. Therefore, a proper injection will result.

In lieu of the screw-threaded connection'ZSi illustrated in Figs. 2 and 3, the disk 21 may simply be formed with a modified bore to receive the rear end of the neck or tube 33, as in Fig. 4. That rear end is then expanded or riveted outwardly, as at 34, to secure the parts against The memberZL-whether it be in 35 concentrically disposed with respect to tube 33.' Otherwise, the tube portion of the assembly, and including the .detent, will correspondto the parts as heretofore described,

excepting only that the head 36 need not be formed with a groove such as 27. Preferably in this form, as well as in the earlier form, the boreof the tube adjacent its outer end is furnished with a countersunk portion 37.

This will lie adjacent the point of theneedle and prevent damaging contact between the latter and the bore sur- 'is preferably achieved by autoclaving, excepting only cap 39', the surfaces of which would be gas sterilized. The assembly would be supplied to a pharmaceutical establishment in the condition shown in Fig. 1, except that stopper 15 would be shifted to the left into contact with stopper 16. i a

For filling purposes,'stopper 16 may be provided with a diaphragm portion in the form of a recess and a groove on its inner face conmiunic'ating with the latter. Disk 21 may be provided with an aligned opening,'all as indicated in dotted lines. By such a construction, a filling needle may be passed through the base defining the recess and caused to expel medicament within the groove of stopper 16,01 in other words, into a space between'this stopper and stopper 15. The former being prevented from moving forwardly, it follows that as'the' compartment is filled under pressure with a proper volume of medicament, stopper 15 will move rearwardly over needle 18 to assume a proper position, as in Fig. 1.

* -After aseptic assembly and with the safety cap or caps removed, the syringes are sterilized preferably by using gas. 1 They are then brought 'back into the Sterile Room and the sterilizedsafety caps assembled. The syringes may now be packed in bulk for shipment. A pharmaceutical house receiving them may again gasisterilize the complete assemblies before transferring them to their Sterile Room. At that point, the-safety'caps are removed :and the triggering mechanism is locked in a filling fixture. A filling needle is introduced through the diaphragm portionofstopper 16 to cause medicament to enter the space between this stopper and stopper. 15. In this man-.

her, the assembly is charged with a proper volume of atropine or other desired liquid. The filling needle is removed and the sterile safety cap iskremounted on the :assembly. The syringes shouldthen preferably be packed in individual cartons in which theyjare distributed to the ultimate users. It will be observed in the foregoing handling and manipulation of the parts. that the powering mechanism may be rotated with respect to needle 18 without disturbingthe relationship of the latter to the The appliance may be stored or carried for indefinite periods of time without detriment. If it were desired to renew the medicament chamber assembly, this could readily be done by employing a construction of the type shown in Figs. 1 to 3. It is apparent in this connection that disk 21 might be attached to casing in any desired manner (such as by screw threads, a snap ring or otherwise). Therefore, with the disk or mounting 21 removed, the needle 13, stoppers and 16 and any associated ampule might be withdrawn bodily from the bore of casing 19. By reversing the procedure, a renewal of the assembly could be achieved. In such renewal it would in most instances be preferable to remove the spring 11 and cup 13.

Upon it being desired to use the assembly, a person will simply remove cap 39. Thereupon, grasping casing 10, the edge of the triggering collar can be brought into contact with the epidermis or the clothing overlying the same in, for example, the region of the thigh. Now, by exerting pressure in the direction of the epidermis, the triggering collar will be caused to slide rearwardly over the tube. This would be true regardless of whether a rubber cup 41 has been employed or not. As the collar is so shifted, its base portion moves rearwardly of the detent element. No objectionable resistance to that movement of the collar occurs, due to the fact that the bevel 25 of the needle and the inclination of bores 30 and 32 are proportioned or related to assure this result. As the base portion of the collar moves beyond the detent, the latter, under the camming or wedge action of the needle bevel, moves upwardly or outwardly to the position indicated in dotted lines in Fig. 3.

Therefore, the power provision within the casing is free to project needle 18. With the needle point moving from the position shown in full lines in Fig. 3 to that indicated in dotted lines, it pierces the diaphragm or base portion of cup 41 (if the latter be employed) and continues into the epidermis or the clothing overlying the same. Simultaneously with this shifting of the parts, the forward face of cup 13 will engage the rear face of stopper 15 and begin to project the latter. With such projection, this stopper will function as a piston, and the desired dosage of medicamentsuch as atropine--will be injected into the user. Accordingly, the plunging of the needle into the desired area and the dispensing of the medicament will be accomplished automatically without any efiort on the part of the user except the removal of the cap and the pressing of the assembly toward the injection site.

Thus, among others, the several objects of the invention as specifically aforenoted are achieved. Obviously, numerous changes in construction and rearrangements of the parts might be resorted to, and the mechanism for restraining the projection of the needle need not necessarily be used in an assembly of the specific type herein illustrated, without departing from the spirit of the invention as defined by the claims.

I claim:

1. A mechanism for restraining the projection of a hypodermic cannula, said mechanism comprising means slidably supporting a cannula, a member shiftably mounted with respect to said supporting means, a detent engageable with the cannula to prevent projection of the latter and means controlled by the shifting of said memher to render said detent inoperative.

2. In a mechanism as defined in claim 1, the cannula being of the type having a pointed and beveled outer end and said detent embracing characteristics cooperable with such a beveled outer end surface to be wedgingly engaged thereby.

3. In a mechanism as defined in claim 2, said member presenting a surface normally restraining outward movement of said detent.

4. In combination, a tubular member formed with a recess communicating with its bore, a hypodermic needle slidably disposed within said bore, a detent engaging with said needle to restrain movement thereof in one direction and detent-releasing means slidably mounted by said memher.

5. In the combination as defined in claim 4, said releasing means extending beyond the end of said needle whereby upon thrust being exerted against such means as it is pressed against a surface, it will be caused to slide on said member.

6. in the combination as defined in claim 5, said needle having a pointed beveled outer end and said detent engaging the beveled surface of said needle.

7. 1n the combination as defined in claim 6, the recess of said member being a bore and said releasing means normally obstructing such bore.

8. In the combination as defined in claim 7, the borerecess extending in a direction rearwardly from the needle point and at angles with respect both to the axis of the bore slidably mounting said needle as well as to a plane perpendicular to such axis.

9. In the combination as defined in claim 7, said releasing means comprising a collar, a base portion forming 11. A hypodermic assembly including in combination a member providing a chamber for medicament, a hollow needle connected therewith, a piston slidably encircling said needle and movable within said chamber for expelling medicament through the lumen of said needle,

power means connected with said needle for projecting.

the latter with respect to said member to pierce tissue and a detent bearing against said needle to restrain its projection.

12. In a hypodermic assembly as defined in claim 11, detent-releasing means forming a part of said assembly and movable with respect to said needle, said releasing. means extending beyond said needle to engage a surface to be pierced thereby, said needle having a beveled outer end and said detent engaging such end surface.

13. In a hypodermic assembly as defined in claim 12, means for connecting said piston with said power means to be removed thereby, said piston comprising a member formed with a bore and the needle having a rear zone slidably extending through said bore and connected to said power means.

14. In a hypodermic assembly as defined in claim 13, said needle being formed with an opening connecting with its lumen at a point between said power means and piston.

15. A hypodermic syringe including in combination a casing providing a medicament chamber, a neck mounted by one end of said casing and formed with a bore, a hypodermic needle formed with a beveled pointed end slidably mounted within said bore and an opposite end in communication with said chamber, a detent movably supported by said neck and bearing against a surface of said needle to restrain movement thereof, releasing means confining movement of the detent, said releasing means extending forwardly of said neck and being shiftable with respect thereto to nullify its confining action and release the needle for movement and means urging said needle to move and to expel medicament from said chamber through the lumen thereof.

16. In a hypodermic syringe as defined in claim 15, the detent engaging the beveled surface of the needle and being movable in a direction radially of the neck beyond the same and said releasing means surrounding said neck and being slidable thereon.

References Cited in the file of this patent UNITED STATES PATENTS

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