Vacuum retractable syringe safety device

A safety syringe with a plunger in which a needle is attached to a mobile component that is mechanically not linked to the plunger but is slidable within the barrel of the syringe and has a valve mechanism for opening a port connecting the interior volume between the mobile component and the plunger to the needle bore. The mobile component is first pushed by the plunger to the bottom of the barrel so that the needle extends normally, the mobile component is mechanically locked in place for use conventionally, and the needle bore is opened. After use, the needle bore may be closed, the lock released, and the mobile component and attached needle sucked back into the barrel by pulling the plunger out, retracting the used needle into the barrel. There may be a plunger lock. There may be an upper barrel locking position for the mobile component.

FIELD OF THE INVENTION

The present invention relates to a syringe, and more particularly to a safety syringe, which prevents injury and contamination during and after its service and is inexpensive to manufacture.

BACKGROUND OF THE INVENTION

In the health care clinical setting a “used” needle (a needle that has already punctured the skin of a patient) is a hazard to all clinicians and technicians who are exposed. Once contaminated by the patient, the sharp needle can then transmit infections to clinicians and technicians who are handling it, should they mistakenly puncture their own skin. This unintended puncturing of an exposed health care worker by a used needle is called a “needle-stick” injury, and is a leading occupational hazard in the health care setting. Between 600,000 to 800,000 needle-stick injuries occur within the hospital setting annually in the U.S., infecting healthcare workers with blood borne pathogens including HIV, HepB, and HepC. As of 2001, OSHA began requiring that all employers replace traditional syringes with safety devices. With the intensifying nationwide concern over reducing healthcare costs, the need has never been greater for a safety syringe that comprises ideal functionality while costing less to manufacture than products currently available.

SUMMARY OF THE INVENTION

The invention, simply stated, is a syringe with a mobile component to which a needle is or can be attached, positionable in a retracted position where the needle, if attached, is enclosed; and which is not mechanically linked to the plunger but can be moved by the plunger and locked in position for use as a conventional syringe. There are other aspects and advantages. In one aspect the invention provides a syringe that may be delivered to the user or administrator in a needle-retracted configuration for safe handling, where a mobile component within the barrel to which a needle is attached or attachable, may be deployed by use of the plunger for moving the mobile component longitudinally to the distal end of the barrel and locking it there for use as in the conventional manner.

In another aspect, the invention provides for retracting the mobile component with its attached needle back into the barrel or cylinder of the syringe by retracting the plunger.

In yet another aspect, the syringe may be filled and employed without ejecting the full dose of solution.

It is a further goal of the present invention to provide for a releasable locking mechanism that permits the mobile component to be moved multiple times between retracted (safe) and extended positions to allow for multiple injections for the same patient.

DETAILED DESCRIPTION

The invention is susceptible of many embodiments. For example, as shown inFIG. 1, in one embodiment a vacuum retractable syringe safety device of the present invention differs from the syringes of the prior art by having a needle110attached to a mobile component120which is configured to be sealingly and slidably moved within the interior length of barrel130of syringe100, and a mechanically separate plunger140, which is likewise configured to be sealingly and slidably moved within the interior length of barrel100by manipulation of its externally extending handle. Syringe100may or may not be configured with a plunger locking mechanism142by which plunger140is held in the up or cocked or retracted position until the plunger locking mechanism is released. The locking mechanism142may be a one-time device such as an external removable pin or key or fused link device, or a reusable or switchable device, the disabling of which permits plunger140to be depressed into the barrel. Barrel130is preferably cylindrical in shape, and has a constant interior wall cross section profile over its length. The barrel may be or have other geometrical shapes, externally and/or internally, as well. Barrel130has an opening135sized to pass needle110and expose the underside or lower side of mobile component120to atmospheric pressure.

Syringe100, in the configuration ofFIG. 1, with mobile component120and needle110encased within barrel130, and plunger140in the retracted position, and optionally locked in the retracted position, is considered “safe” for handling. The syringe may be configured in this manner for shipping and storage, and initial handling prior to first use, and reconfigured in this manner during use if appropriate, and after use for final handling and disposal. Opening135may optionally be closed by a disposable or reusable seal or cap that must be removed prior to using the syringe.

Referring toFIG. 2, depressing plunger140necessarily pushes adjacent mobile component120downward as well, towards the distal end of barrel130. Referring toFIG. 3, mobile component120and attached needle110arrive at and snap lock into its final extended position at the distal end of barrel130, by means of a locking mechanism that is further described below. Mobile component120remains locked in place at the end of syringe barrel130throughout the use of syringe100. This allows syringe100to be operated as a standard, non-safety syringe. Referring toFIG. 4, the retracting of plunger140draws fluid150through needle110into barrel130in the conventional manner, and permits it to likewise be expelled in the conventional manner.

FIGS. 1-4can also be viewed as a sequence of operation, in the context of the description above.

As illustrated inFIG. 4, the process of filling or loading the syringe with solution150is no different from the process of filling a normal, non-safety syringe: the safety syringe operates as a traditional non-safety syringe once the mobile component120is locked into place at the distal end of barrel130.

The process of administering solution150to the patient is also no different from the process of administering solution from a normal, non-safety syringe. Similar to a normal, non-safety syringe, the clinician would puncture the skin of the patient with needle110, push needle110to the desired depth, and then push plunger140forward using an appropriate amount of force to inject the desired amount of solution into the patient.

When the desired amount of solution150has been administered, the needle retraction process and function is initiated. Not all of the solution in the barrel is required to be ejected from the syringe in order for the needle retraction function to be employed. Any amount of solution up to the maximum capacity of the device can remain in the barrel.

Referring now toFIGS. 3, 4, and 5, the needle retraction process and function is illustrated and explained. Any, as inFIG. 4, or no, as inFIG. 3, residual volume of solution150may remain in the syringe between mobile component120and plunger140, without interfering with the needle retraction process. First, release lever132is depressed so as to retract the mobile component locking mechanism and close the orifice leading to the needle bore, which as is further illustrated in other figures and described below. This closes the needle bore and prevents any change in the volume of air or fluid between mobile component120and plunger140. Referring toFIG. 5, when plunger140is then manually retracted in the conventional manner, mobile component120and attached needle110are drawn by the resulting reduced fluid pressure between mobile component120and plunger140, upwards into barrel130, thereby retracting the mobile component120and needle110. Plunger140may optionally be locked in the retracted position so as to make “safe” the syringe until needed for reuse or disposal.

It will be readily apparent that there is some advantage to embodiments having barrel130of sufficient length to contain a full dose of solution, meaning the length of a “draw stroke” of the plunger for extracting a full dose from the solution source, plus the length of the needle. This provides for the syringe to be filled in the conventional manner and the mobile component then released from its locked position and retracted to where the needle tip is fully within the barrel for safe handling prior to re-extending the mobile component and administering the first dose of solution. Other embodiments may have shorter barrels relative to their fluid capacity, length of needle and draw stroke, and still enjoy many benefits of the invention.

Following contamination of the needle by the puncturing of the patient's skin, mobile component120and attached needle110may be manually released from the locked position and then retracted.FIGS. 2 and 5illustrate the position of needle110and mobile component120during mid-retraction.FIG. 1illustrates the position of needle110and mobile component120after retraction is complete. Conventional extraction of needle110from the patient can be achieved by pulling syringe100away from the patient, as done with a normal, non-safety syringe. The safety retraction mechanism of the device can be employed following complete extraction of needle110from the patient.

However, the device also allows for use of the needle retraction safety mechanism while needle110is still in the patient, extracting the needle from the patient directly into the barrel of the syringe, thus preventing needle110from being exposed to the external environment while needle110is being extracted from the patient's skin. In the former situation, mobile component120remains in the locked position while needle110is being removed from the patient, exposing the needle for possible unintended re-puncture of the patient or jury to the administrator, or other contact that might further contaminate the needle. In the latter situation, mobile component120is unlocked while needle110is still inside patient, and the retracting plunger easily withdraws the mobile component and needle with it. Either way, once mobile component120is unlocked, both mobile component120and needle110are drawn back into barrel130of the syringe by pulling plunger140in the backward direction.

As shown inFIG. 5, the mechanism of extension and retraction of the mobile component using the mechanically separate plunger exploits simple rules of pressure and volume. The volume between plunger stopper141and mobile component120is fixed when the lock mechanism is released, so that the extension or retraction pressure on plunger140is transmitted by the fixed volume155to mobile component120, extending or drawing that component back into the barrel concurrently with plunger motion. This assumes, of course, that the seals and bore valve are functional so that there is no significant leakage by the seals or through the bore valve when tension or pressure is applied to the plunger.

As seen inFIG. 1-5, barrel130consists of a partially open end135which exposes the distal side of mobile component120to atmosphere air outside barrel130. When mobile component120is locked at the distal end of barrel130, there is an opening, or “solution canal”125A, that allows solution to pass between barrel130and needle110through the needle bore during the ejection or drawing of solution. When mobile component120is unlocked and therefore free to move linearly within barrel130(as illustrated inFIGS. 1, 2 and 5), this solution canal125A is blocked, preventing air or fluid from entering space155and holding the contained volume constant during retraction and re-extension. Solution canal125A is only open when mobile component120is locked in place at the distal end of barrel130.

In the illustrated embodiments, the blocking and unblocking of solution canal125A is synchronized with the locking system of mobile component120, as described below. It will be appreciated that other embodiments may uncouple these functions, or provide alternative logic to their respective operations so that, for example, the needle bore may be opened and/or closed by a separate release mechanism, but only when the mobile component lock is engaged. Extending on that example, by way of a further example, when the mobile component is locked in the extended position, the opening to the solution canal and needle bore for release of solution may be triggered by increasing plunger pressure and thereafter close again when plunger pressure is released, or when full plunger stroke is achieved. Simple pressure release valves are known to provide this type of functionality.

Significant forces at work during the retraction process include: atmospheric pressure pushing mobile component120in the axial direction back into barrel130; the static and kinetic friction of the seals of mobile component120and plunger stopper141with respect to the interior wall surface of barrel130; and the force being applied to the plunger140and transmitted to mobile component120by the fixed volume of fluid between them.

Once some or all solution in barrel130has been injected into the patient and employment of the safety mechanism is desired, the administrator will unlock or release mobile component120from its fixed position by pressing on lever132at the distal end of barrel130, and begin pulling plunger140backward. In doing so, the pressure of the contained space155is reduced relative to atmospheric pressure, thus creating suction on mobile component120, allowing atmospheric pressure to push mobile component120back into barrel130.

It should be noted that the function of lever132may be duplicated by an external rotatable ring on barrel130, that by manual rotation engages one or more of the protruding lock bars and depresses them radially or non-radially inward so as to unlock the mobile component to move within the barrel. Alternative, barrel130may be equipped with a slideable release ring that by longitudinally sliding on barrel130likewise engages one or more protruding lock bars and depresses them sufficiently to release their grip on the barrel. Other and various externally manipulated release mechanisms will be readily apparent to one of ordinary skill in the art, and are within the scope of the invention.

For example, referring toFIG. 11, the distal end of barrel130is flanged inwardly so that the diameter of the opening of barrel end135is of a smaller diameter than that of mobile component120, but larger than the diameter of needle110, so as to prevent mobile component120from moving beyond its farthest point in the distal direction, but still freely allow air to be admitted into and out of the lower end of barrel130during operation of the mobile component retraction and extension functions. The locking mechanism in this embodiment is configured to extend longitudinally downward from the mobile component with one or more spring loaded, pawl-shaped hooks134, preferably but not necessarily a pair of opposing hooks, pivotally mounted to mobile component base122and radially oriented to be inwardly compressed as they ride over the flange lip of barrel end135, and then partially re-extend under pressure of spring126, as they hook on the flange lip, thereby locking mobile component120in position within barrel130. The opposite end of hooks134are pivotally connected to locking bars125, which in this embodiment are limited to their port valve function, normally keeping port125A closed but upon engagement of the mobile component with the barrel end by action and motion of hooks134, slid apart to open port125A to fluid flow.

Regarding the barrel end opening135, in alternate embodiments the central diameter of barrel end135may more closely conform to the external needle diameter for support or otherwise, and there may be other ventilation holes and/or latching holes or recesses in the barrel end flange to accommodate air flow and/or longitudinally extending latching hooks as described above.

Also, as is well understood in the art, as in a conventional syringe an air seal at the top of the barrel around the plunger handle must be avoided. The proximate or upper end of the barrel must be ventilated in some manner above the plunger stopper upper travel limit, as around the plunger handle, to permit airflow into and out of the top of the barrel above the plunger stopper in concert with plunger motion.

Mobile component120may or may not require lubrication, which is likewise true of rubber stopper141on plunger140, to minimize the frictional forces as it slides up and down barrel130of the syringe. Efficient retraction of mobile component120and needle110requires good barrel wall seals on the sliding components, with minimal friction or resistance to sliding between mobile component120and the inside of barrel130in particular. Stated otherwise, in the vacuum retractable syringe safety device, the coefficients of static and sliding/kinetic friction of the selected sealing materials of mobile component120and the inside surface of syringe barrel130must be relatively small. In the traditional syringe as well as in syringes of the invention, the rubber stopper on the plunger that makes contact with and seals the walls of the barrel, the equivalent of plunger stopper141of these embodiments, may or may not be lubricated.

It should be noted that syringe100may be packaged with needle110already attached to mobile component120, and already retracted within barrel130, with barrel end135optionally sealed, thus eliminating the need for an additional plastic needle cover that a separate and attachable needle would require. However, needle110may also be attached as a separate component after mobile component120is locked into place. The syringe may be adapted to accept a variety of needle sizes.

Traditional syringes are packaged either with needles pre-attached or separate from the needles. When needles are packaged separately, they are manually screwed onto the end of the barrel. Embodiments of the invention have the capability of having needle110screwed into needle base129of mobile component120after mobile component120is locked into place at the distal end of barrel130. Therefore, whether or not the needle was pre-attached or added at the time of service to the mobile component, the operation of the device is the same.

In one embodiment of the invention, the connection between needle base129and needle110is identical to the universally standardized screw-on connection between needles and non-safety syringes. This allows each vacuum retractable syringe safety device to be compatible with all needle lengths/sizes (as separate parts). This compatibility is more useful, however, when the syringe is pre-packaged without a needle because it is not ideal to have to remove a first needle (especially one without a cover) from a syringe to replace it with different needle.

There are a number of alternative ways in which the locking function for the mobile component can be accomplished. One embodiment provides a locking mechanism that holds mobile component120in place at the distal end of the syringe barrel130in the manner illustrated inFIGS. 6-10. As illustrated, mobile component120comprises a collar121within which is contained a base plate122and a cover plate128, the planes of which are perpendicular to the axis of collar121. Radially oriented slots123in base plate123intersect at port125A, which extends through base plate122and cover plate128. Openings121A in collar121are configured to be aligned with the outboard end of slots123. Locking bars125are slidably contained in slots123by cover plate128, and are sized to engage and functionally close off port125A when retracted, with their outboard ends being flush with or slightly inboard of the exterior surface of collar121.

A spring126is held in compression between tabs127on locking bars125so as to push them normally outward. In this embodiment, a gear set126A is provided to interlock bars125so that they are constrained to extend or retract together, assuring a uniform locking function when extended and a uniform closure of port125A when retracted. It will be appreciated that in other embodiments, fewer or more locking bars may be used, and also other locking bar interlock mechanisms, or no interlock mechanism, may be used.

At any location of the mobile component other than fully extended, locking bars125bear lightly on the inner wall of barrel130under pressure of spring126. There are corresponding lock slots132A on the distal end of barrel130. When mobile component120is pushed to the end of barrel130where it reaches its flange stop, locking bars125come into alignment with lock slots132A and are free to extend under pressure of spring126, sufficiently far to lock mobile component130in position within the barrel. For embodiments equipped with a hard linked (two-way) locking bar interlock mechanism, the bars will necessarily extend together if all are clear and able, and retract together if any one is pushed back. For embodiments equipped with a return only interlock system, the bars will extend independently, each if it is clear and able, but the positive retraction of any one locking bar will retract the full set.

It will be readily apparent fromFIGS. 1-5to one of ordinary skill in the art that the retraction function can be exercised with a full or partial load of fluid in the barrel, either before or following an initial injection, if the barrel is of sufficient length.

FIGS. 9 and 10disclose one embodiment of the invention having an externally accessible lever132by which the administrator may disengage the locking mechanism from the mobile component to allow for retraction of the mobile component and needle. Depressing the lever pushes locking bar125inward so that it is clear of locking slot132A. An interlocking gear set causes any other locking bars to be retracted at the same time. The retraction of the locking bars has two important consequences; port125A is closed whereby the interior volume between the plunger stopper141and the mobile component is held constant, and the mobile component is unlocked and free for being retracted by retracting motion of the plunger.

In other embodiments, there may be an upper mobile component locking position in the proximal end of the barrel that is structurally and functionally similar to the distal end locking mechanism, with upper locking slots in the barrel wall and upper release levers. This may be used as an initial or starting position, or a final, post-injection position, where the needle is fully enclosed.

Other and numerous simple lock and release systems are clearly possible to one of ordinary skill in the art, without necessity of being illustrated in detail. For example, there may be configured on the underside or outboard face of the mobile component one or more longitudinally extending spring loaded locking pawls or hooks, off set from the center of the mobile component or otherwise clear of the needle, that engage a locking slot or flange at the barrel end, optionally causing the fluid port to be opened to the needle bore. Such locking mechanisms may be similarly released by application of an externally applied release force at the distal end of the barrel so as to close the port and allow retraction of the mobile component.

As previously described, other and numerous mechanisms may be employed in other embodiments for affecting the unlocking of the locking bars constraining the mobile component. One of ordinary skill in the art will appreciate that such mechanisms may extend up the barrel to where they are more easily accessed and actuated by a digit of the same hand holding the syringe.

And yet, upon exposure to this disclosure, one of ordinary skill in the art will readily appreciate that there are other and numerous embodiments within the scope or equivalent to the claims appended here to. For example, there is a safety syringe that has a barrel; a plunger; and a mobile component; where the barrel has a proximate end and a distal end, the distal end is configured with a mobile component stop such as an inwardly flanged end or other structural interference with longitudinal travel of the mobile component, and a needle opening. The plunger is configured with a plunger stopper slidingly and sealingly engaged within the barrel, with a plunger handle extending from the proximate end of the barrel by which the plunger stopper may be moved longitudinally within the barrel as in a conventional syringe. The mobile component is slidingly and sealingly engaged within the barrel and configured with a fluid port connecting an inboard face facing the plunger stopper with an outboard face facing the distal end of the barrel. The outboard face is configured to accept attachment of a syringe needle whereby the axial bore through the needle is in communication with the port.

The mobile component and the barrel are cooperatively configured with a lock and release mechanism such as has been described elsewhere herein, whereby the mobile component is lockable in a fixed position at the distal end of and within the barrel, and is releasable thereafter for longitudinal motion within the barrel. The fluid port may have a valve mechanism operable to open and close the port to fluid flow.

In yet another embodiment, the lock and release mechanism and the valve mechanism may be cooperatively linked such that opening of the port to fluid flow occurs with locking of the mobile component in the fixed position and closing of the port to fluid flow occurs with release of the mobile component for longitudinal motion

As another example, one embodiment may have a lock and release system where the mobile component is configured with at least one locking bar that is extendable radially outward beyond the inner diameter of the barrel, or downward into the barrel end structure, by operation of the plunger directly or indirectly, for engagement with the barrel for locking, and is releasable by operation of an externally accessible release mechanism on the barrel for releasing the locking pawl or bar. Depressing the plunger directly or indirectly pushes the mobile component to the far end of the barrel. The plunger stopper either contacts the mobile component directly if the syringe is empty or compresses whatever fluid is in the syringe thereby pushing the mobile component to the end of the barrel. The arrival of the mobile component at the distal end of the barrel triggers a lock mechanism, bar, hook or pawl, by any of numerous means such as but not limited to: a pre-loaded spring action, a hydraulic action due to fluid pressure, or a mechanical linkage with the barrel end that causes the locking bar or bars to be engaged with the locking slot or barrel end flange or like recess or structure upon which a locking bar may gain purchase to resist upward motion of the mobile component.

In other embodiments, the valve mechanism may consist of motion of at least one locking bar between a position where the port is unobstructed to fluid flow, and a position where the port is closed to fluid flow. In yet other embodiments, there may be multiple locking bars that upon retracting to a retracted position close the port to fluid flow and upon extension to a locked position open or come apart in a manner that opens the port. The release mechanism may be any structure arranged on or incorporated into the barrel assembly for pushing at least one locking bar from its respective locked position back into its retracted position.

In other embodiments, the mobile component may have or incorporate a locking bar interlock mechanism whereby retracting one locking bar retracts all the locking bars together. There are numerous mechanisms for doing this such as but not limited to a gear set or a rotational linkage where all locking bars connect or are pulled inward by a rotatable concentric ring. The function of such an interlock mechanism may be configured to extending all locking bars with the extension of any one locking bar. The locking bars may be independently or collectively spring biased for extension, so that they will extend if brought into alignment with a locking slot in the wall of the barrel, which means any recess or structural anomaly in the wall surface that will accommodate extension of a locking bar in such a way as to restrict or inhibit further longitudinal motion of the mobile component . . . .