JP2024540277A - Medical Syringe - Google Patents

Abstract

A medical safety syringe includes an injection molded plastic body having a tubular barrel, lateral finger flanges surrounding the barrel, a plunger assembly disposed forward of the finger flanges and having a substantially flat outwardly facing surface, two upwardly projecting wings, and slidably engaging an inner wall of the barrel, a needle having a tip projecting forwardly from the barrel, and a needle safety shield slidably engaging the body between the two wings. The lateral finger flanges have a window through which a core pin can be inserted during injection molding of the body. The plunger assembly has a proximal end cap that is integral with the plunger handle and abuts the rearwardly facing surface of the lateral finger flanges. At the distal end of the needle safety shield is a cylindrical needle guard that is movable forwardly after use of the syringe to protect the needle tip.
[Selected figure] Figure 3

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 16/370,239, filed March 29, 2019, which is a continuation-in-part of U.S. patent application Ser. No. 15/940,305, filed March 29, 2018.

The present invention relates to a safety syringe configured for medical use to aspirate or inject fluids, the safety syringe not having a retractable needle. As used herein, the term "safety syringe" means a syringe having one or more structures and/or protective features that function or cooperate to reduce the likelihood that a user of the syringe or a subsequent handler, a patient, or a bystander will experience an inadvertent, accidental, or unintended needle stick from a needle or cannula that is part of or used in connection with the syringe.

Syringes for medical use are typically made with a removable plunger cap. The plunger cap serves to prevent contaminants from entering the syringe barrel through the annular space that would otherwise exist around the plunger handle at the rear of the barrel prior to use of the syringe. Such plunger caps are typically removed and discarded prior to use. There is a need for a safety syringe that does not require the manufacture, use, or disposal of a removable plunger cap prior to use of the syringe.

Medical syringes are typically made with barrels with roughly cylindrical inner and outer walls, meaning that volumetric dose indicia and other markings are applied to the arcuate outer surface during manufacturing. This can be difficult, especially when the barrel diameter and radius of curvature of the outer wall are small (such as 1 mL, 0.5 mL, and smaller syringes), when the available outer surface area is very limited, or for syringes where different dose graduations or other indicia are applied to both sides of the barrel. In these instances, it is often necessary to spin or rotate the barrel during printing, and indicia such as dose measurement lines and associated numerical values or other markings are often difficult to read because they wrap around the barrel quite a bit. This problem is even more pronounced with small diameter, low dose syringes where the numerical value of the dose is less than "1" and must be preceded by a "0". In this instance, when focusing on the volumetric indicia to determine the fluid level in the syringe, the main number identifying the dose associated with the injection may not be visible. These design flaws can confuse users, especially elderly users with poor or weakened eyesight, and lead to medical errors.

Other design flaws exist in certain so-called "safety syringes" that have needle shields or guards that are rotated into place after injection. Before and during injection, such shields or guards often obscure or block significant portions of the dosage scale and markings, also creating a risk of medical error.

Certain "safety syringes" that have longitudinally extending hubs or other slidable safety elements have other design deficiencies that increase the overall length of the syringe and contribute to "dead space" within the syringe. A syringe is needed that protects users, patients, and bystanders from accidental needlesticks without increasing the amount of dead space. Reducing the amount of dead space within a syringe is necessary to reduce medication waste and increase the number of doses available from a single vial.

Other design deficiencies exist with syringes that have a flat, marked surface configured as a sleeve or clip that can be attached to the syringe barrel. Such syringes require the manufacture of additional parts and contribute to positioning and alignment errors, which in turn contribute to dosing errors.

For at least these reasons, there is a need for a low-dose safety syringe with factory-applied dose markings and other indicia and a barrel with an integrally molded, readily visible, printable surface. Desirably, such a syringe would be manufacturable using high speed injection molding methods and equipment that would implement low dead space, protect users and patients from accidental needlestick injuries, and also reduce the cost per syringe.

During the recent ongoing global pandemic of coronaviruses and other virulent pathogens, there is an increased demand for safety syringes that can be rapidly and reliably produced in a variety of sizes and needle gauges. At the same time, there is an increased emphasis on the need for improved syringe designs that are more efficient and inexpensive to manufacture, and that reduce material and packaging costs. There is a need for a syringe that combines safe and reliable needlestick protection with an integrally molded, flat, printable indicator display surface and a plunger assembly that does not require the use of a separate, selectively removable plunger cap. There is also a need for a safety syringe body embodying the aforementioned features that does not require the use of a slide to mold an undercut, but instead is configured to provide clearance for a core pin during injection molding of the syringe body, facilitating the use of 64 cavity molds, thereby increasing production capacity and reducing production costs. Such a safety syringe is disclosed herein.

Prior documents disclosing other products having components that may be in the same technical field include, for example, U.S. Patent Application Publication No. 2015/0231335 A1 and U.S. Patent No. 4,946,447.

A satisfactory embodiment of the safety syringe of the present invention preferably comprises an injection molded plastic body having an annular barrel with a needle holder projecting forwardly at a distal end of the annular barrel, finger flanges projecting laterally near the proximal end of the annular barrel, a cylindrical collar projecting rearwardly from the barrel behind the laterally projecting finger flanges, and two longitudinally extending wings continuous with the barrel and projecting upwardly from the barrel in parallel spaced apart relationship. Each wing has an integrally molded inwardly facing support guide rail that extends longitudinally and slidably engages a cooperating sized and aligned channel in a needle safety shield. Each wing further comprises a substantially flat outwardly facing surface preferably having an array of volumetric marking indicia and dosage numbers disposed adjacent a lower portion of the barrel for easy reading by a user. The proximal end of each wing abuts the side of a window located above the barrel in the lateral finger flange. The window is not present in the finger flanges of known prior art syringes and is provided to allow insertion and retraction of a core pin between the wings during molding to facilitate more efficient molding, thereby reducing manufacturing time and product costs.

In some examples of the present disclosure, the two wings of the body may be said to project "tangentially" from the barrel. As used in these instances, "tangentially" means that the two extended wings extend generally upward from either side of the upturned portion of the barrel, and not laterally outward from the barrel as do the wings used to stabilize some prior art medical devices, such as catheter introducers, against a patient's body part. Those skilled in the art of injection molding of plastic devices, such as the body of the safety syringe of the present invention, will understand that design criteria, such as draft angles and radii of curvature, may require modifications that do not strictly conform to the mathematical definition of "tangential". Such modifications may be required, for example, to facilitate molding and reduce stress concentrations along the base of each of the wings that are integrally molded as part of the barrel portion of the body. Similar design modifications may be required when each of the wings is integrally molded to an individual guide rail.

The forwardly projecting needle is preferably fixedly attached to a needle holder located at the distal end of the barrel, and a selectively removable needle cover is preferably provided to protect the needle tip and prevent inadvertent needle stick injury or contamination prior to use of the syringe. The needle cover preferably has a closed distal end and a proximal open end that frictionally engages the forwardly extending nose of the barrel.

The invention also preferably includes a plunger assembly, further including an elongated handle insertable into the barrel through an opening in a rearwardly projecting cylindrical collar behind the lateral finger flanges of the body. A resilient plunger seal is disposed at the distal end of the plunger handle and slidably engages the inner wall of the tubular barrel. The proximal end of the handle preferably includes a rigid end cap with a forwardly projecting cylindrical collar that fits around and slidably engages the rearwardly projecting cylindrical collar of the body. A majority of the outer periphery of the forwardly facing cylindrical collar preferably abuts a portion of the rearwardly facing surface of the lateral finger flanges when the plunger is fully advanced within the barrel. The forwardly facing cylindrical collar eliminates the need for a separate plunger cap as required in prior art syringes to prevent contaminants from entering the rear of the barrel prior to use.

When the needle cover is attached and the plunger is advanced within the barrel such that the forward projecting cylindrical collar of the plunger abuts the rearward facing surface of the lateral finger flange, the interior fluid contacting portions of the syringe are sealed and protected from contamination regardless of whether the syringe is enclosed within another package. This allows the syringes to be assembled and shipped together prior to packaging and sterilization.

A longitudinally extending needle safety shield is disposed above and aligned parallel to the tubular barrel. The needle safety shield desirably includes an actuation handle having opposing elongated channels cooperatively configured and aligned to provide longitudinal sliding engagement with support guide rails integrally molded on the inwardly facing surfaces of the wings. The actuation handle also desirably includes a textured, upwardly facing touch surface that facilitates application of manual pressure to initiate forward sliding movement of the needle safety shield to reposition forward a cylindrical needle guard disposed at the distal end of the needle safety shield into a position surrounding the needle tip after use to protect patients and medical personnel from accidental needlestick injuries and associated risks of infection by blood-borne pathogens. The cylindrical needle guard is desirably disposed about the forward-facing cylindrical nose of the barrel prior to forward movement of the actuation handle during storage and use of the syringe. Additionally, the wings' longitudinal support guide rails desirably cooperate with interference elements, ramps, and shoulder stops molded into the inwardly facing surfaces of the wings to limit sliding of the sliding safety shield relative to the barrel when necessary during use of the syringe, as described below. A primary advantage of the present invention is the body design with windows through the finger flanges that allow for insertion and retraction of the core pin, and allows for molding of undercuts for the interference elements, ramps, and stops in the body without the need for slides.

Each of the body wings is continuous with the barrel and includes a base projecting upwardly from the barrel and an outwardly facing substantially flat display surface having a printed dose marking. The two oppositely disposed wings may have the same or different dose scales to facilitate volumetric measurements marked in different units. The invention is particularly useful in syringes having a usable volume of 1 mL or less. Such syringes typically have small barrel diameters such that the volumetric dose markings applied to the outer surface wrap around most of the circumference of the barrel. In accordance with one embodiment of the invention, a pad printing technique (sometimes referred to as "tampography") is used to apply the volumetric dose markings or other markings to the substantially flat display surface of the syringe. As used herein, the term "substantially flat" refers to the general configuration of the relevant surface and may include relatively small protrusions and recesses, particularly slight curvatures, drafts, or small undulations with such features resulting from the applied indicators or other markings.

The safety syringe of the present invention embodies the necessary needle protection features for safety measures without the need for a retractable needle and without the increased cost. This embodiment of the present invention combines the benefits of a flat, printable surface with more easily readable dosage markings with the cost benefits of a simpler, yet still effective and easy to use needle safety device to provide a safer and more affordable solution for widespread administration of injections, particularly for vaccines, flu shots, and treatments for people who require frequent injections (e.g., insulin) to treat various chronic health conditions, or for people living in developing locations. Furthermore, because the dosage markings and markings are more easily readable by the user, there is less risk of administering an incorrect dosage of the medicinal fluid to the patient ("medical error"), and thereby causing other unintended consequences.

The safety syringe of the present invention preferably embodies a broader, substantially flat display surface disposed on the medical syringe which, in cooperation with the substantially flat edges of the circumferential lateral finger flanges, helps to prevent the syringe from rolling off a tray or other flat surface. The substantially flat surface also allows for a relatively narrow flange around the barrel compared to flanges on conventional syringes having tubular barrels, providing a larger surface area for easier viewing of the display surface by the user. The opposing substantially flat wing surfaces also improve stability and the degree of control a user can exercise over the syringe during an injection or other procedure.

The safety syringe of the present invention is also desirably characterized by less "dead space" between the plunger and the needle, for example, as compared to other prior art and competing syringe configurations. As used herein, the term "dead space" means the internal volume occupied by the medical fluid remaining in the syringe when the plunger is fully advanced within the barrel. Excessive dead space can lead to waste of medical fluid during injection and can also cause undesirable air bubbles to form in the liquid chamber of the syringe when the liquid is withdrawn. By using a syringe with less dead space, in some cases, the user can obtain an additional dose from each vial of medication. The syringe of the present invention is particularly useful for administering relatively small amounts of medical fluid, such as insulin or vaccines, to a user by injection or infusion, although the syringe structure and operation are not limited to any particular size, dose, or procedure.

Another embodiment of the present invention is disclosed, which embodies a needle safety shield preferably embodying one, preferably two opposing substantially flat indicator display surfaces, and a needle tip guard extending circumferentially around the needle and preferably coaxially aligned with the needle. The needle tip guard is attached, connected, or integrally molded with an actuation handle that slidably engages the body. Suitable rails, ramps, stop shoulders, detents, or other similarly effective means are preferably provided as part of the needle safety device and barrel so that the actuation handle advances smoothly with little interference when desired and does not subsequently inadvertently retract to expose the needle tip. The needle safety device of this embodiment of the present invention does not need to have a needle retraction mechanism or needle storage cavity to protect the user from accidental needle sticks, nor does it need the barrel to slide laterally relative to the needle. After use of the syringe, manual pressure is applied to a touch surface of the actuation handle located behind the needle and needle tip guard to selectively advance the needle tip guard to protect the user from the forward protruding needle tip. The actuation handle is slidably engaged with the body of the syringe and is slidable forward relative to the barrel from a first position in which the needle tip is uncovered to a second position in which the needle tip is surrounded by a needle tip guard and protected from accidental needle sticks. When the needle safety device is fully extended relative to the barrel, the needle tip is preferably positioned completely inside the needle tip guard, so that a person handling a used syringe cannot inadvertently stick a needle stick by simply placing a fingertip on the tip of the syringe.

In another embodiment of the invention, the barrel and the actuation handle include cooperatively engageable elements that allow for manually controllable longitudinal sliding movement of the actuation handle relative to the barrel between two predetermined stop positions. The first stop position is a fully retracted use position in which the needle tip guard substantially surrounds the nose. The second stop position is a fully extended post-use position in which the needle tip shield surrounds the forwardly projecting tip of the needle.

While in one preferred embodiment of the invention, the forwardly projecting needle is fixedly disposed in the nose of the barrel, it will be understood by those reading this disclosure that similarly configured syringes may be made with needles configured for selective attachment to the barrel by the use of threads or other similarly effective means.

These and other features of the present invention will be better understood by considering the following detailed description of various embodiments and the appended claims in conjunction with the accompanying drawings.

The syringe of the present invention will be further described and illustrated in relation to the following drawings.
1 is a top front perspective view of one embodiment of the present invention, with the removable needle cover attached in a position that allows multiple syringes to be combined, shipped, and stored. The plunger is fully advanced within the barrel, with the forwardly projecting cylindrical collar of the plunger end cap abutting a portion of the rearward facing surface of the lateral finger flange. FIG. 2 is a top rear perspective view of the embodiment of FIG. 3 is an exploded top front perspective view of the embodiment of FIG. 1. FIG. FIG. 4 is a top front perspective view of the embodiment of FIG. 1 with the removable needle cover removed. FIG. 5 is a left side view of the embodiment of FIG. FIG. 6 is a cross-sectional side view taken along line 6-6 of FIG. FIG. 7 shows the state of FIG. 6 with the plunger partially pulled out relative to the body. FIG. 8 is an upper front perspective view of FIG. 4 with the needle safety shield advanced to cover the forwardly protruding needle. FIG. 9 is a left side view of FIG. FIG. 10 is a cross-sectional view taken along line 10-10 of FIG. FIG. 11 is an enlarged view of the distal portion of FIG. FIG. 12 is an enlarged view of the distal portion of FIG. FIG. 13 is a front view of FIG. FIG. 14 is a front view of FIG. FIG. 15 is a plan view of the body 12 of FIG. FIG. 16 is a top view of the syringe 10 of FIG. FIG. 17 is a top view of the syringe 10 of FIG. FIG. 18 is a cross-sectional view taken along line 18-18 of FIG. FIG. 19 is a cross-sectional view taken along line 19-19 of FIG. FIG. 20 is a cross-sectional view taken along line 20-20 of FIG. FIG. 21 is a cross-sectional view taken along line 21-21 of FIG. FIG. 22 is a cross-sectional view taken along line 22-22 of FIG. FIG. 23 is a cross-sectional view taken along line 23-23 of FIG. FIG. 24 is a cross-sectional view taken along line 24-24 of FIG. FIG. 25 is a cross-sectional view taken along line 25-25 of FIG. 26 is a side cross-sectional view of the body shown in FIG.

With reference to Figures 1-3, the safety syringe 10 comprises a body 12, a needle safety shield 14, a plunger assembly 16, a needle 18, and a removable needle cap 20. The body 12 is preferably molded from a medical grade polymeric material and has sufficient transparency to allow a user to clearly view the level of liquid drawn into the barrel 22. The body 12 further comprises two substantially parallel, spaced apart, upstanding wings 24, 26 that project tangentially above the barrel 22 to define an axially extending elongated space 28 therebetween. The outwardly facing surface of at least one, and preferably both, wings 24, 26 is preferably substantially flat and includes an array 74, 75 of volumetric indicia applied to the viewing surface.

Arrays 74, 75 may, for example, include at least Arabic numerals identifying the number of fluid units and associated primary measurement indicia. However, it will be understood that the accompanying drawing figures are for illustrative purposes and are not drawn to scale, and that the placement of some features, such as minor unit markings, may vary from the locations shown. At least a portion of the indicia or markings may desirably begin on the substantially flat outwardly facing viewing surfaces of walls 24, 26 and may optionally continue for a short distance onto the curved outer wall of barrel 22. Such placements are recognized to be within the operational capabilities of known pad printing technology and are now readily available to those skilled in the art.

The finger flange 30 is disposed transversely to the barrel 22 and projects outwardly around the barrel 22 and the proximal ends of the wings 24, 26. The finger flange 30 further includes a window 32 having a bottom that is continuous with the upper surface of the barrel 22, a side that is continuous with the proximal ends of the inwardly facing surfaces of the wings 24, 26, and an upper edge 31 (FIGS. 1 and 2). The upper edge 31 bridges the upper side of the window 32 and provides structural support and reinforcement for the upwardly projecting proximal ends of the wings 24, 26. A cylindrical collar 33 extends rearwardly from the finger flange 30 and provides a rearwardly facing opening that is coaxially aligned and in communication with the inner wall of the barrel 22. The body 12 of the safety syringe 10 further includes a cylindrical nose 35 that protrudes forward from the barrel 22 and a needle holder 42 that protrudes forward from the cylindrical nose 35.

The needle safety shield 14 includes an elongated actuation handle 65 that is preferably configured to fit between and slidably engage the upstanding walls 24, 26 of the body 12. Axially extending channels 64 (FIG. 3) are provided on either side of the actuation handle 65 and project inwardly from the inwardly facing surfaces of the wings 24, 26 for slidably engaging cooperating sized and aligned support guide rails 34, 36. The needle safety guide further includes an upwardly facing, preferably textured, touch pad 62 to facilitate application of finger pressure necessary to selectively reposition the slidably engaged needle safety shield from a first position to a second position after use of the syringe. The forwardly extending portion of the actuation handle 65 is preferably downwardly curved and includes an inner wall 70 that defines an internal passage 68 and is joined to an integrally molded cylindrical needle guard 67. The inner wall 70 of the cylindrical needle guard 67 is desirably sized and aligned to slidably engage the outwardly facing surface of the cylindrical nose 35 of the body 12 when the channel 64 of the actuation handle 65 of the needle safety shield 14 receives and slidably engages the inwardly facing support guide rails 34, 36 of the body 12 during assembly of the safety syringe 10.

3, the plunger assembly 16 includes an elongated plunger handle 44 having a distal projection 46 and a concave annular seating surface 48 for a resilient plunger seal 50. The resilient plunger seal 50 further includes a rear collar 52 mountable to the distal projection 46 and a forward facing end surface 54. With reference to FIGS. 3, 6, and 7, the resilient plunger seal 50 is desirably configured to provide a fluid seal against the inner wall of the barrel 22 when the distal end of the plunger handle 44 is inserted forwardly through the rearwardly projecting cylindrical collar 33 of the barrel 22 of the body 12 and slidingly engaged therewith. With further reference to FIGS. 3, 6, and 7, the proximal end of the plunger handle 44 of the plunger assembly 16 is desirably integrally molded with a plunger thumb cap 60. The plunger thumb cap 60 has a forwardly projecting cylindrical collar 56 that is configured to slide forwardly over the rearwardly projecting cylindrical collar 33 of the barrel 22 when the plunger seal 50 and plunger handle 44 are inserted forwardly into the barrel 22 during assembly of the safety syringe 10 into the configuration shown in Figures 5 and 6. The rear end of the needle 18 is insertable into the needle holder 42 and is attached to be fixed thereto, such as by using an adhesive or another similarly effective commercially available means.

As shown in Figures 5 and 6, the safety syringe 10 is fully assembled with a needle cap 20 covering a forwardly projecting needle 18 having a forward needle tip 86, and a plunger handle. The plunger handle is fully disposed forwardly within the barrel 22 such that a cylindrical collar 56 projecting forward from the plunger end cap 60 abuts the rearwardly facing surface of the finger flange 30. When the safety syringe 10 is configured as shown in Figures 5 and 6, the interior of the barrel 22 is protected from external contamination without the need for a separate plunger cap as would be required for use with the syringes described above. The inner surface 58 of the cylindrical collar 56 of the plunger assembly is preferably configured to slidably engage the outer surface of the rearwardly projecting cylindrical collar 33 of the body 12.

4, the safety syringe 10 is shown in a "pre-use" configuration with the needle cap 20 (FIGS. 1 and 2) removed. The needle 18 projects forward from the needle holder 42 of the barrel 22, the needle safety shield 14 is in its first rest position, and the cylindrical needle guard 67 is disposed in its pre-use position around the needle holder 42 and the cylindrical nose 35. As shown in FIGS. 1, 3, 6, and 11, the radial clearance between the outer surface of the cylindrical nose 35 and the inner wall 70 of the cylindrical needle guard 67 is preferably sufficient to allow the rearwardly extending cylindrical portion 80 of the selectively removable needle cap 20 to be inserted therebetween and frictionally engage the outer surface of the cylindrical nose 35. The length of the side wall 76 of the needle cap 20 is preferably sufficient to accommodate needles of various lengths and gauges (e.g., needle 18) and to prevent the needle tip 86 (FIG. 6) from engaging the rigid end cap 78 prior to use of the safety syringe 10. Referring to FIG. 11, when the plunger handle 44 is fully advanced inside the barrel 22, a small amount of dead space 84 exists inside the needle holder 42 between the plunger seal 50 and the proximal end of the needle 18.

Referring now to Figures 4 and 7, with the needle cap 20 removed, the cylindrical needle guard 67 still positioned around the needle holder 42 and the cylindrical nose 35 of the body 12, and the needle safety shield 14 still positioned in its first rest position, the needle 18 can be inserted into the vial, and the plunger cap 60 of the plunger assembly 16 can be withdrawn a desired distance relative to the barrel 22 to form a fluid chamber 82 within the barrel 22 for withdrawing the injection fluid.

During injection, the plunger handle 44 is again fully advanced inside the barrel 22 as shown in Figures 8-10 and 12, after which light hand pressure is preferably applied to the upwardly facing touch surface 62 of the actuation handle 65 of the needle safety shield 14 to initiate forward movement of the needle safety shield 14 within the elongated space 28 relative to the barrel 22 and wings 24, 26 of the body 12. This repositions the actuation handle 65 to a second stop position where the slide 65 moves forward over the ramp 40, as best shown in Figure 10. The actuation handle 65 is then "locked" in the second stop position and prevented by abutment of the forward-facing shoulder of the ramp 40 and the rearward-facing end face 72 of the actuation handle 65. When this occurs, the cylindrical needle guard 67 moves forward to a position where the needle tip 86 of the needle 18 is disposed inside the cylindrical space 68, preventing the needle tip 86 from causing an accidental needlestick injury to the user of the safety syringe 10, the patient, a bystander, or any subsequent handler.

Referring to Figures 13 and 14, a front view of the safety syringe 10 shows the wings 24, 26, the support guide rails 34, 36, the barrel 22, the end wall 78 of the needle cap 20, the upturned touch pad 62 and cylindrical needle guard 67 of the actuation handle 65, the needle holder 42, the cylindrical nose 35, and the lateral finger flange 30. In Figure 13, the needle cap 20 is in place, and in Figure 14, the needle cap has been removed.

15, which is a plan view of the body 12, the needle holder 42 and cylindrical nose 35 project forward from the barrel 22, and the cylindrical collar 33 projects rearward behind the finger flange 30. The upper edge 31 (FIG. 3) of the window 32 is visible and connects and supports the upper portions of the wings located on either side of the axially extending space 28 located above the barrel 22. The support guide rail 34 projects inward from the inward wall of the wings 24, and the support guide rail 36 projects inward from the inward wall of the wings 26. With reference to FIGS. 3 and 15-16, the opposing interference elements 38, 39 are integrally molded and are preferably configured to frictionally engage the needle safety shield 14 (FIG. 16) and provide slight resistance to forward sliding thereof while the needle safety shield 14 is located in the first stop position and the cylindrical needle guard 67 is around the cylindrical nose 35 and needle holder 42 of the body 12. 16-17, following an injection, forward finger pressure on the upwardly facing touch surface 62 of the actuation handle 65 of the needle safety shield 14 causes the needle safety shield 14 to slide forward over the interference elements 38, 39 and ramps 40, 41 (FIG. 17) to a second stop position (also referred to as the "safe" position) in which the cylindrical needle guard 67 surrounds the tip 86 of the needle 18 (visible in FIG. 16). With reference to FIGS. 10 and 17, once the needle safety shield 14 reaches the second stop position, rearward movement of the needle safety shield 14 relative to the barrel 22 and needle 18 is desirably prevented by face-to-face abutment between the rearwardly facing shoulder 72 of the needle safety shield 14 and the forwardly facing shoulders of the ramps 40, 41. This abutment prevents the cylindrical needle guard from re-exposing the needle tip 86 after the needle safety shield 14 is moved to the second stop position following use of the safety syringe 10.

26 is a longitudinal cross-sectional view of the body 12 shown in FIG. 15, with arrows 90, 92 shown for illustrative purposes to indicate the direction and extent to which the opposed injection molding core pins can be inserted into the space 28 between the wings 24, 26, and the desired location of the core pin stop line 94. This facilitates integral molding of the longitudinally extending support guide rails 34, 36, the interference elements 38, 39, and the ramps 40, 41 projecting inwardly from the inner surfaces of the wings 24, 26 without the need for slides. This facilitates the use of molds with larger cavities, increasing manufacturing efficiency and reducing the manufacturing costs of the barrel 12 and safety syringe 10 (FIG. 1).

Figure 18 is a cross-sectional view of the barrel 12 taken along line 18-18 of Figure 15, further illustrating how the support guide rails 34, 36 project inwardly from the wings 24, 26 into the axially extending space 28 on the barrel 22, and also illustrates the forward facing surfaces of the ramps 40, 41 located forward of the window 32 of the lateral finger flange 30. The void shown inside the barrel 22 is the space that becomes the fluid chamber 82 after insertion of the plunger assembly into the interior of the barrel.

Figure 19 is a cross-sectional view of the barrel 12 looking rearwardly at the rear of the support guide rail, showing the space 28 between the wings 24, 26, with the window 32 of the finger flange 30 only obstructed by the forward facing faces of the opposing interference elements 38, 39 and the ramps 40, 41. The upper edge 31 of the window 32 provides structural support and integrity between the window 32 of the finger flange 30 and the portions of the wings 24, 26 that are continuous with it.

Figure 20 is a cross-sectional front view of the finger flange 30 taken along line 20-20 in Figure 15, showing the wings 24, 26, interference elements 38, 39, ramps 40, 41, and the proximal end of the needle holder 42 located in front of the barrel 22.

21 is a rear cross-sectional view taken along line 21-21 of FIG. 16, illustrating the sliding engagement between the support guide rails 34, 36 of the needle safety shield 14 and the longitudinal channels 64 located on either side of the actuation handle 65. The upwardly facing touch surface 62 of the needle safety shield 14 is visible above the actuation handle 65, and the forward facing surfaces of the ramps 40, 41 are visible within the space 28.

FIG. 22 is another rear cross-sectional view taken along line 22-22 of FIG. 16, partially illustrating the assembled body 12 and needle safety shield 14 as seen through the upward touch surface 62 when the needle safety shield 14 is in a first rest position relative to the barrel 22 of the safety syringe 10.

FIG. 23 is a cross-sectional front view taken along line 23-23 of FIG. 16, forward of the finger flange 30 and rear of the needle safety shield 14. FIG. 23 shows the proximal end face 72 of the actuation handle 65 and the underside of the actuation handle 65, which curves downward to join the cylindrical needle guard 67.

Figure 24 is a rear cross-sectional view taken along line 24-24 of Figure 17 after the needle safety shield 14 has moved forward from the first stop position to the second stop position and the cylindrical needle guard has moved forward to protect the needle tip 86 (Figure 16) of the needle 18. Figure 24 is a cut through the end wall 72 of the actuation handle looking rearward at the top of the touch surface 62.

FIG. 25 is a cross-sectional front view of the front side of the finger flange 30 taken along line 25-25 of FIG. 17, showing the wings 24, 26, the interference elements 38, 39, and the proximal end 72 of the needle safety shield 14 blocked by a portion of the ramps 40, 41.

Upon reading this specification in conjunction with the accompanying drawings, it will become apparent to those skilled in the art that various other modifications and variations can be made to the embodiments disclosed herein, and the scope of the present invention is limited only by the broadest interpretation of the appended claims to which the inventors are legally entitled.

Claims (13)

In medical safety syringes,
an injection molded plastic body comprising: a tubular barrel having an inner wall, a proximal end and a distal end; a forwardly projecting needle holder, a cylindrical nose at the distal end; a finger flange projecting laterally from the barrel near the proximal end; a first cylindrical collar projecting rearwardly from the finger flange to the distal end of the barrel; and two upstanding wings disposed forward of the finger flange, the two upstanding wings projecting from the barrel and extending forwardly from the finger flange parallel and spaced apart above the barrel;
a needle attached to the needle holder and projecting forwardly therefrom, the needle having a distal needle tip;
a plunger assembly including an elongated plunger handle having a proximal end and a distal end, the distal end of the plunger handle having a resilient plunger seal inserted into the barrel through a rearwardly facing opening in the first cylindrical collar and slidably engaging an inner wall of the barrel, the proximal end of the plunger handle having an end cap having a forwardly projecting second cylindrical collar that fits around and slidably engages the rearwardly projecting first cylindrical collar of the body and abuts a rearwardly facing surface of the finger flange when the plunger is fully advanced within the tubular barrel;
a longitudinally extending needle safety shield disposed above and between the two upstanding wings of the barrel and aligned with the barrel;
Equipped with
The needle safety shield further comprises an actuation handle having a proximal end and a distal end, the actuation handle slidably engaging the body and having an upwardly facing touch surface that facilitates a user applying hand pressure to initiate forward sliding of the needle safety shield relative to the body to selectively reposition a cylindrical needle guard located at the distal end from a first position that surrounds the cylindrical nose of the barrel during storage and use of the safety syringe to a second position that protects the needle tip after use of the safety syringe. The safety syringe of claim 1, wherein each wing includes an inwardly projecting, longitudinally extending support guide rail that is slidably engageable with the actuation handle of the needle safety shield. The safety syringe of claim 2, wherein each extended support guide rail is sized to cooperate with and aligned with an extended channel disposed on an adjacent side of the actuation handle, and the extended channel is slidably engageable with the support guide rail. The safety syringe of claim 1, wherein the finger flange includes a window through which a core pin can be inserted and retracted during injection molding of the body. The safety syringe of claim 4, wherein the window is sized to cooperate with and aligned with the actuation handle of the sliding safety shield. The safety syringe of claim 4, wherein the window has a side that is continuous with the proximal end of the inward wall of each upright vane. The safety syringe of claim 6, wherein the window has an upper portion that bridges the two spaced apart upright wings to provide structural support. The safety syringe of claim 2, wherein each support guide rail is integrally molded as part of the wing from which it projects. The safety syringe of claim 1, wherein at least one upstanding vane comprises a substantially flat outwardly facing surface having indicia related to a volumetric measurement of fluid disposed within the syringe. The safety syringe of claim 9, wherein each upstanding vane has a substantially flat outwardly facing surface having indicia related to a volumetric measurement of fluid disposed within the syringe. The safety syringe of claim 1, wherein the longitudinally extending support guide rail cooperates with an interference element formed on an inwardly facing surface of the upright vane to limit sliding of the needle safety shield relative to the barrel. The safety syringe of claim 11, wherein the interference element includes a ramp portion having a forward-facing stop shoulder. The safety syringe of claim 12, wherein the sliding safety shield includes a rearward facing stop surface that engages the forward facing stop shoulder of the ramp portion to prevent rearward movement of the needle safety shield relative to the body after placement of the cylindrical needle guard in the second position.

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