Sealed-hypodermic Syringe

Abstract

A sealed hypodermic syringe comprising a cylindrical syringe body having a discharge opening at one end with a sealing membrane extending across the opening. A ferrule is disposed on the syringe body adjacent the discharge opening, the ferrule carrying a double-pointed needle and hub assembly arranged for longitudinal movement between an advanced position wherein the inner end of the needle is spaced from the sealing membrane, and a retracted position wherein the inner end pierces the membrane and communicates with fluid contained within the syringe body. A spring biases the needle to its retracted position, and a cover having a hollow bore houses the protruding portion of the needle. Press-fitted into the bore of the cover is an insert ring having locking shoulders which cooperate with ears of the needle-hub assembly to retain the needle in its advanced position against the action of the spring prior to the first use of the syringe. To ready the syringe for use the cover is turned slightly. This releases the advanced needle whereupon the action of the spring instantly snaps it to the retracted position, The inner end of the needle thereby pierces the sealing membrane and communicates with the syringe chamber, enabling discharge therefrom to be effected. Once the cover has been removed and the needle has snapped to its retracted, operative position, the cover can no longer be replaced and retained to house the needle. Thus, prior use of the syringe will be indicated.

Description

BACKGROUND

This invention relates generally to disposable hypodermic syringes, and more particularly to pre-loaded devices of this type employing a retractable needle which is adapted to pierce a sealing membrane of the syringe body, to render the syringe operable.

Syringes for the above purpose usually have an anti-contamination elongate, removable cover intended to house the needle and maintain the sterility thereof, as well as to prevent damage prior to use. In one prior construction there is employed a ferrule and a needle-hub assembly having a threaded portion at one end, which is cooperable with an internal thread on a removable, antiseptic cover. The arrangement is such that, during assembly, the needle is urged to an advanced position against the action of a spring carried in the ferrule, thereby to enable the thread on the hub to be engaged by threads of the cover as the latter is screwed in place. The cover engages a portion of the ferrule and thus maintains the needle in its advanced position. Immediately prior to use, the cover is unscrewed, enabling the spring to snap the needle to its retracted position wherein it will pierce the sealing membrane and communicate with the syringe chamber.

The above construction has a number of distinct drawbacks. First, during both the assembly and the use of the syringe, the cover is required to be turned through several revolutions in order to insure adequate and positive engagement and disengagement of the threads. This operation represents a significant amount of time when it is considered that such disposable devices are manufactured in quantities of millions. Second, in the event that the threads of the hub and cover become seized or bind due to aging or temperature and humidity changes, there is no satisfactory way to release the needle since in such event the cover and the needle assembly will all turn simultaneously. Third, where automatic equipment is employed to assemble the covers to the needle hubs, problems are encountered due to slight variations in the threads from unit to unit, so that careful alignment of the cover and hub has to be maintained at all times in order to insure that the threads engage and become "started" properly. Moreover, in automatic assembly, the threaded engagement can result in excessive tightening of the cover on the hub, causing difficulty in removal of the cover by the user. In addition to the foregoing, the cost of manufacture is quite high for a throw-away item, because the forming of the cooperable threads is fairly expensive.

SUMMARY

The above disadvantages and drawbacks of prior hypodermic syringes are obviated by the present invention which has for an object the provision of a novel and improved syringe which is especially simple in its construction and fabrication so as to reduce manufacturing costs, while at the same time having an improved and effective operation. A related object of the invention is the provision of an improved hypodermic syringe as above set forth, wherein the needle movement is more precisely and accurately controlled, especially with respect to the penetration of the seal. Still another object resides in the provision of a syringe as above characterized, wherein the non-contaminating cover can always be easily and quickly removed, enabling the syringe to be immediately readied for use at all times.

The above objects are accomplished by providing, in a hypodermic syringe device comprising a syringe body and sealing membrane with a double-pointed needle adapted to pierce the membrane, a novel needle lock constituted of ears on the needle and cooperable locking shoulders on an anti-contamination or sealing-type cover. The cover, by means of its shoulders, holds captive a needle hub so as to releasably hold the needle in its advanced position against spring action. Upon turning the cover slightly, the shoulders thereof disengage the ears of the needle hub and the needle snaps to its retracted position wherein it pierces the membrane to enable discharge of the product to be effected.

Other features and advantages will hereinafter appear.

In the drawings, illustrating a preferred embodiment of the invention:

FIG. 1 is a side elevational view of the improved hypodermic syringe of the present invention, showing the anti-contamination cover in place.

FIG. 2 is a fragmentary section taken on line 2--2 of FIG. 1, showing the needle in its advanced position,

FIG. 3 is a view like that of FIG. 2, except illustrating the needle in its retracted position, the cover having been rotated 90.degree.,

FIG. 4 is a top plan view of a metal insert ring carried in the cover of the syringe of FIGS. 1-3,

FIG. 5 is a side elevation of the insert ring of FIG. 4,

FIG. 6 is a section taken on line 6--6 of FIG. 4,

FIG. 7 is a sectional view of the novel needle cover employed with the hypodermic syringe of the present invention,

FIG. 8 is an end elevational view of a part of the needle hub assembly of the syringe of FIGS. 1-3,

FIG. 9 is a section taken on line 9--9 of FIG. 8,

FIG. 10 is an end elevational view of another part of the needle hub assembly of the syringe of FIGS. 1-3, and

FIG. 11 is a section taken on line 11--11 of FIG. 10.

Referring first to FIGS. 1-3 there is illustrated a hypodermic syringe generally designated by the numeral 10, comprising a syringe body 12 defining a syringe chamber 14. A plunger assembly 16 of conventional construction is slidable in the body 12. A ferrule 18 is secured to the syringe body 12 adjacent the end 20 thereof, by crimping of the edge portion against a shoulder of the body as shown.

In accordance with the present invention there is provided a novel needle lock or retainer device, which is cooperable with an anti-contamination syringe construction that comprises as shown a sealing membrane 21 extending across the opening 20 of the body and forming a sealed closure for the syringe chamber 14. The syringe construction has a double-pointed needle 24 longitudinally movable between advanced and retracted positions with respect to the ferrule and syringe body, the advanced position being illustrated in FIG. 2 and the retracted position being illustrated in FIG. 3. The syringe further has a needle-hub assembly comprising a hub 26 which is press-fitted onto the needle 24. The novel needle retainer or lock of the invention comprises a key member 28 which is press-fitted onto the hub 26 and is rigid therewith, said key member being cooperable with retainer means in the cover 22, to be described below. The cover 22 is elongate, as shown, and has a hollow bore 30 to receive the needle.

Referring now to FIGS. 1-6, the cover 22 is provided with unique retainer means comprising a metal insert ring 32 having a pair of retainer shoulders 34 and 36 (FIG. 4) and a pair or upstanding lugs 38 and 40 (FIG. 5), the purpose of which will be explained below.

As best illustrated in FIGS. 2 and 3, the bore 30 of the cover has an annular bead 42 which retains the insert ring 32 in place, the latter being forced part the bead during its assembly into the cover. Spaced about the periphery of the ring are three projecting tabs 44, 46 and 48 which extend into the wall of the bore 30 of the cover, the latter yielding slightly to enable this to occur, such that the insert cannot undergo any inadvertent rotation with respect to the cover after it is installed therein.

The needle hub 26 is illustrated particularly in FIGS. 8 and 9, and comprises an elongate body portion 50, a base portion 52 of substantially circular configuration, and a longitudinal bore 54. One portion of the bore has a reduced diameter to enable the hub to be press-fitted over the needle. Referring to FIGS. 2 and 3, there is press-fitted onto the hub 26 the key member 28 particularly illustrated in FIGS. 10 and 11, the member having a pair of outwardly extending locking or retainer ears 56 and 58. It is to be understood that the needle 24, the hub 26 and key member 28 are all rigid with respect to one another, and move as a single unit.

Referring again to FIGS. 2, and 3, there is provided a compression spring 60 carried in the ferrule 18 and engaging the base portion 52 of the hub, biasing the hub 26 and needle 24 to a retracted position (FIG. 3) wherein the needle has pierced the sealing membrane 21 and communicates with the syringe chamber 14. The retracted position is determined by the engagement of the hub base 52 with a stop ring portion 62 of annular configuration, constituting part of a seal cap which fits within the ferrule 18 and which receives the resilient sealing membrane 21. As illustrated in FIGS. 2 and 3, the stop ring 62 and sealing membrane 21 are held in place by the ferrule 18 which is crimped around the shoulder of the body 12.

In accordance with the present invention there is further provided a sealing means on the cover 22 and ferrule 18 for closing off the bore of the cover and protecting the needle from contamination, the sealing means comprising an annular internal lip 64 in the bore 30 of the cover, and a corresponding annular external shoulder 65 on the ferrule. With the cover in place, as illustrated in FIG. 2, the needle 22 is completely isolated from external contamination, and thus a high degree of sterility can be maintained.

The operation of the improved hypodermic needle of the present invention can now be readily understood. The purpose of the sealing membrane is to isolate the contents of the syringe chamber from the needle until immediately prior to use. During the assembly of the syringe, the needle 34, hub 26, and key member 28 are first applied to the ferrule 18 from opposite sides before the latter is crimped onto the body 12. The key member 28 is press-fitted onto the hub 26, and the spring 60 is partially compressed as illustrated in FIG. 3. The cover 22 is then installed over the needle and onto the ferrule 18, with the cover positioned in a manner that the ears 56 and 58 (FIG. 10) of the key member are oriented to pass by and not interfere with the shoulders 34, 36 respectively of the metal insert ring 32 (FIG. 4) in the cover. Next, the needle assembly is shifted in the ferrule to compress the spring 60 more fully (FIG. 2) and project the needle a greater extent from the ferrule. The cover 22 is then rotated through approximately one-quarter of a turn, at which time the ears 56 and 58 of the key member will become disposed inside of the shoulders 34, 36, and will engage the stops 38 and 40 (FIG. 6) of the insert ring 32. When the cover is now released, the needle will be held in an advanced position as shown in FIG. 2 due to the engagement of the locking ears 56, 58 of the key member 28 with the locking shoulders 34 and 36 of the insert ring. To this assemblage is applied the stop ring 62 and membrane 22, and the ferrule is then crimped onto the body 12. The syringe will now have the appearance of FIG. 2. The chamber can be filled with a predetermined quantity of serum at a later time.

When the syringe is ready to be used, the cover 22 is twisted one-quarter of a turn counterclockwise as viewed from the closed end thereof, such that the shoulders 34 and 36 of the insert ring disengage the ears 56 and 58 of the key member 28. When this occurs the spring 60 will snap the needle 24 and hub 26 to the retracted position of FIG. 3, wherein the needle pierces the membrane 22 and communicates with the syringe chamber 14. The retracted position of the needle is defined by the engagement of the base portion 52 of the hub with the stop ring 62.

It will be readily understood that once the cover has been rotated and the needle snapped to its retracted position there is no further retaining force on the cover, since the ears 56 and 58 (FIG. 3) no longer engage the shoulders 34, 36 of the insert ring. Moreover, the cover cannot again be reassembled on the ferrule of the needle or the needle hub urged to its advanced position once the cover has been removed. Thus, a positive indication of prior use or tampering is given by the arrangement of the present invention.

There are a number of advantages to the present construction. First, the initial assembly of the syringe is simplified, since a twist of only one-quarter turn need be applied to the cover to effect engagement of the shoulders 34 and 36 thereof to the ears 56 and 58 of the key member 28. It will be understood, however, that the automatic assembly equipment employed can impart a larger amount of twist during this assembly, this merely resulting in frictional turning of the needle and hub after engagement occurs of the stops 38, 40 of the insert ring 32 by the ears 56, 58 (such turning being of a non-damaging nature).

Second, there is virtually no danger of the cover becoming "seized" on the hub assembly, since the frictional drag between the shoulders 34 and 36 and the ears 56 and 58 respectively is very small compared to the frictional drag on the base portion 52 of the hub 26 by the spring 60. Lastly, by the present construction, the needle pierces the membrane without undergoing rotation relative thereto. This anti-coring feature is significant, since even slight rotation of the needle as it pierces the membrane could cause tearing thereof, with the result that minute particles of membrane material could enter the needle or become lodged in the inner end and cause clogging thereof.

From the above it can be seen that I have provided a novel and improved hypodermic syringe which is especially simple in construction and fabrication, so as to be economical to manufacture, and which further is reliable and foolproof in operation, providing effective isolation of serum from needle contamination during storage. It thus represents a distinct advance and improvement in this field.

Variations and modifications are possible without departing from the spirit of the invention.

Claims

I claim:

1. In a hypodermic syringe, the combination of:

a. a syringe body having a discharge opening at one end,

b. a sealing membrane extending across the discharge opening and adapted to be pierced in order to provide access to the syringe body,

c. a ferrule secured to the syringe body at the dicharge opening,

d. a double pointed needle,

e. means mounting the needle in the ferrule for longitudinal movement between advanced and retracted positions,

f. a needle hub secured to the needle at a point intermediate its ends,

g. spring means biasing the needle to a retracted position wherein one end of the needle pierces the sealing membrane,

h. a cover removably connected with the syringe body, and

i. cooperable means on the cover and the needle hub, releasably holding the needle in an advanced position against the action of the spring means,

j. said cooperable means releasing the needle hub in response to turning of the cover with respect to the syringe body through a small fractional part of a revolution, thereby to enable the spring means to snap the hub and needle to a retracted position wherein the membrane is pierced to enable discharge from the syringe body through the needle,

k. said cover having a hollow bore to house the needle,

l. said cooperable means comprising a shoulder in the bore of the cover,

m. said needle hub having an outwardly extending ear engageable with and disengageable from the shoulder of the cover in response to turning of the latter in one direction or another,

n. said shoulder comprising an insert ring press-fitted into the bore of the cover, and

o. a stop carried in the bore of the cover on the ring and engageable with the ear of the needle hub when the needle is in the advanced position, for limiting turning movement of the cover with respect to the hub.

2. The invention as set forth in claim 1, wherein:

a. said insert ring is of metal and said shoulder and said stop are carried thereon.

3. The invention as set forth in claim 1, wherein:

a. the bore of said cover has an internal annular bead for permanently retaining the insert ring in a fixed position.

4. The invention as set forth in claim 1, and further including:

a. sealing means carried on the cover and the ferrule for closing the bore of the cover and protecting the needle from contamination.

5. The invention as set forth in claim 4, wherein:

a. said sealing means comprises an annular internal lip on the cover, and

b. an annular external shoulder on the ferrule.

6. The invention as set forth in claim 1, wherein:

a. said insert ring and shoulder, and said stop are constituted as a single, integral piece.

7. The invention as set forth in claim 1, wherein:

a. said insert ring has a projecting tab biting into the inner wall of the cover, to prevent relative turning movement between the latter and said ring.

8. In a hypodermic syringe, the combination of:

a. a syringe body having a discharge opening at one end,

b. a sealing membrane extending across the discharge opening and adapted to be pierced in order to provide access to the syringe body,

c. a ferrule secured to the syringe body at the discharge opening,

d. a double pointed needle,

e. means mounting the needle in the ferrule for longitudinal movement between advanced and retracted positions,

f. a needle hub secured to the needle at a point intermediate its ends,

g. spring means biasing the needle to a retracted position wherein one end of the needle pierces the sealing membrane,

h. a cover removably connected with the syringe body,

i. cooperable means on the cover and the needle hub, releasably holding the needle in an advanced position against the action of the spring means,

j. said cooperable means releasing the needle hub in response to turning of the cover with respect to the syringe body through substantially less than one-half of a revolution, thereby to enable the spring means to snap the hub and needle to a retracted position wherein the membrane is pierced to enable discharge from the syringe body through the needle, whereby the syringe is readied for use by mere rotation of the cover through a part of a turn,

k. said cover having a hollow bore to house the needle,

l. said cooperable means comprising a shoulder in the bore of the cover,

m. said needle hub having an outwardly extending ear engageable with and disengageable from the shoulder of the cover in response to turning of the latter in one direction or another, and

n. a stop carried in the bore of the cover and engageable with the ear of the needle hub when the needle is in the advanced position, for limiting turning movement of the cover with respect to the hub.