Syringe plunger

Abstract

A syringe plunger 10 comprising an elongate stem 12 having a tip 14 at one end for receiving a seal and an integral thumb loop 20 at the other end. The thumb loop 20 may comprise a base 20a having a b

Description

Field of the Invention This invention relates generally to a syringe plunger, and a syringe incorporating such a plunger, particularly, but not necessarily exclusively, suitable for use in medical and cosmetic procedures in which the location of insertion of the syringe needle and, therefore, the handling and manipulation of the syringe, must be easily and precisely controlled. Background of the Invention Conventional hypodermic syringes are well known to medical and other professionals, as well as the general public, for intravenous or intramuscular injection of medicaments and other substances. A typical syringe comprises a generally tubular barrel, open at both ends, with an external finger flange extending around the ‘top’ open end (when oriented for normal use), and narrowing to a tip at the other end, the tip being configured to receive thereon a hypodermic needle. In many cases, the tip incorporates an integral female luer lock connector, and the housing in which the hypodermic needle is mounted incorporates an integral male luer lock connector, such that the hypodermic needle assembly can be quickly and easily attached to the syringe barrel by screwing the male luer lock connector within its housing onto the female luer lock connector integrated into the tip of the syringe barrel. A conventional hypodermic syringe also comprises a plunger, comprising an elongate stem having a substantially planar thumb rest at one end and a seal at the other end. The seal, usually formed of rubber, or a rubber-like material, is of substantially the same diameter as the inner diameter of the syringe barrel, and sealingly engages against the inner wall thereof so that it can slide up and down within the barrel in response to pressure / force on the plunger (usually applied at the thumb rest end). The plunger stem has a maximum diameter less than the inner diameter of the syringe barrel and is typically characterised by two or more longitudinal grooves along its length. The thumb rest typically has a diameter greater than that of the opening at the top end of the syringe barrel. Whilst such prior art syringes are effective for many medical applications, there are many other types of medical and cosmetic procedures that require much more precise control over the handling and manipulation of the syringe than is possible with conventional syringes of this type. For such procedures, it is typical for specially-designed syringe to be utilized, that is configured, and has features and functions, specific to the procedure for which it is intended. For example, an aspirating syringe is commonly used in dentistry to inject local anaesthetic around a gum region in which a dental procedure is to be performed. Very precise location and control of the needle and injection amounts is required for this. Accordingly, a specially-designed aspirating syringe is used, tat has a small ‘harpoon’ at one end of the plunger and a circular loop at the other end (in place of the thumb rest described above). The finger flange is typically wider than that of a conventional syringe and, in some such devices, may even be replaced by a pair of loops through which the dental practitioner can place their thumb and / or finger(s), during use. Other types of control syringes are known, that are typically designed and configure for specific procedures, but none of these specially-designed syringes are suitable for more general applications. They are typically very large syringes, such as those designed for angiographic catheterization and other specific medical procedures, and are not adaptable for use in any other medical or cosmetic application. In recent years, cosmetic procedures have become increasingly numerous and prevalent. Such cosmetic procedures often involve injecting material, such as dermal filler products, under the skin of a patient to, for example, enhance facial features and plump and fill lines, grooves and sunken areas. The location of the injections depends on the particular application, as well as the results to be achieved, and the dermal filler material must be injected in very small amounts, very precisely, in multiple locations in order to achieve the desired result. Accordingly, a small syringe, with a very fine needle, is typically used, and very fine and careful control, in terms of handling and manipulation of the syringe, is required. Typically, very small syringes are supplied in industry standard sizes (often pre-filled with dermal fillers or other products or medicaments), and are generally configured as a conventional syringe of the type described above. However, the planar thumb rest and standard finger flange do not always provide or facilitate the precise control required. Reusable adaptors are available, comprising a loop-shaped element that is removably affixable to the thumb rest, and a separate component, comprising a pair of finger loops, that is removably affixable to the finger flange. However, there are a number of issues associated with such adaptors. For example, it is essential that these are sterile when used, and must be re-sterilised after each use, and then stored in a manner that maintains their sterility until they are next needed for use. Furthermore, during use, bacteria can collect between the removable adaptor elements and the parts of the syringe to which they are affixed, especially as they wear and perhaps become slightly warped from repeated use and sterilisation. Still further, it is a common occurrence for the loop-shaped element to become inadvertently detached from the syringe plunger when aspirating (pulling back on the plunger) during use, which could cause injury to the patient. Aspects of the present invention seek to address at least one or more of these issues. Statements of invention In accordance with a first aspect of the invention, there is provided a syringe plunger for a syringe comprising a tubular barrel, open at one end and narrowing to an open-ended tip at the other end, the syringe plunger comprising an elongate stem having a tip at one end for receiving a seal thereon and an integral thumb loop at the other end thereof. In an embodiment, the thumb loop may comprise a base having a bottom surface from which the stem extends orthogonally and substantially centrally, and an opposing top surface. The base may be curved, so as to be generally concave when viewed from the top surface in the direction of said tip. The base may be curved about its longitudinal and / or its lateral axis. Advantageously, the tip of the syringe plunger may be screw threaded, such that it can be screwed directly into a plunger seal. This facilitates maximal purchase into a rubber (or rubber-like) seal, so that, when aspirating, the plunger stem and loop do not inadvertently separate from the seal. Advantageously, a plurality of integral protuberances may be provided on the bottom surface of the base. In an embodiment, the base may comprise a pair of opposing longitudinal side edges, said side edges being outwardly curved such that the width of the base at its centre is greater than that at its ends. In an embodiment, the thumb loop may be generally triangular with externally rounded corners, wherein a pair of side walls extend from respective end edges of the base to a rounded apex furthest from the proximal end of the stem. In another embodiment, the thumb loop may comprise a generally C-shaped wall, the ends of which are integrally coupled to the top surface of the base, adjacent the respective end edges thereof. In yet another embodiment, the thumb loop may comprise a generally circular or oval loop member that is integrally coupled, generally centrally, to the top surface of the base. Advantageously, the elongate stem may have one or more external longitudinal grooves therein. According to another aspect of the present invention, there is provided a syringe comprising a tubular barrel that is open at one end and narrows to an open-ended tip at the other end, said open-ended tip being configured to receive thereon a hypodermic needle, the syringe further comprising a syringe plunger substantially as described above, slidably mounted in said barrel, and having a seal coupled to the tip of said stem, the diameter of said seal being substantially equal to the inner diameter of the tubular barrel. One of the benefits of a syringe plunger according to an exemplary embodiment is that it can be designed as a universal component, that can fit securely into the plunger seal of, for example, an existing dermal filler syringe. However, the present invention is not necessarily intended to be limited in this regard. These and other aspects of the invention will be apparent from the following detailed description. Brief Description of the Drawings Embodiments of the invention will now be described, by way of examples only, and with reference to the accompanying drawings, in which: Figure 1A is a schematic perspective view of a syringe plunger according to an exemplary embodiment of the invention; Figure 1B is a schematic front view of the syringe plunger of Figure 1 A; Figure 1C is a schematic side view of the syringe plunger of Figure 1A; Figure 2A is a schematic perspective view of a syringe plunger according to an exemplary embodiment of the invention; Figure 2B is a schematic front view of the syringe plunger of Figure 2A; Figure 2C is a schematic side view of the syringe plunger of Figure 2A; Figure 3A is a schematic perspective view of a syringe plunger according to an exemplary embodiment of the invention; Figure 3B is a schematic front view of the syringe plunger of Figure 3A; Figure 3C is a schematic side view of the syringe plunger of Figure 3A; Figure 4A is a schematic perspective view of a syringe plunger according to an exemplary embodiment of the invention; Figure 4B is a schematic front view of the syringe plunger of Figure 4A; Figure 4C is a schematic side view of the syringe plunger of Figure 4A; and Figure 5 is a schematic front view of a syringe according to an exemplary embodiment of the invention. Detailed Description Referring to Figures 1A, 1B and 1C of the drawings, a first example syringe plunger 10 comprises an elongate stem 12 having an integral, screw-threaded tip 14 at its distal end for receiving thereon (removably or otherwise) a seal (not shown) of a diameter substantially equal to the inner diameter of the syringe barrel for which it is intended. The syringe barrel can be selected according to the volume of product required for a specific procedure, and / or it may be selected according to its diameter (for example, smaller diameter syringe barrels offer greater control over quantity and pressure of product delivery). Typical dermal filler syringes, for example, could have a volume of between 0.2 and 1ml, but the present invention is not necessarily intended to be limited in this regard. The screw-threaded tip 14 allows it to be screwed directly into a plunger seal (not shown in Figures 1A-C), thus allowing the tip 14 to fit securely into the plunger seal of, for example, an existing dermal filler syringe, facilitating maximal purchase, such that the plunger seal does not become detached from the plunger when aspirating, in use. This, in turn, allows the syringe plunger to be designed as a universal component that can replace the syringe plunger of an existing ‘standard’ syringe. The stem 12 comprises a distal end portion 12a that extends, from the end of the stem 12 that is adjacent the tip 14, along a small portion of its length. The remainder of the stem 12 is denoted generally as stem portion 12b in Figures 1Aand 1B. The outermost lateral circumference of the stem portion 12b is generally circular. However, longitudinal rectangular grooves 16 are provided on respective opposing sides of the stem portion 12b, each rectangular groove 16 extending from the distal end portion 12a, along substantially the entire length of the stem portion 12b. The distal end portion 12a of the stem 12 also has a pair of generally rectangular grooves 18, extending circumferentially, on opposing sides thereof. At the proximal end of the stem 12, an integral thumb loop 20 is provided. In this example, the thumb loop 20 is generally triangular with rounded corners. The base 20a of the integral thumb loop 20 is located nearest the stem 12, and comprises a substantially flat, generally rectangular central region having integral curved opposing side edges 22a such that the base 20a of the thumb loop 20 is slightly concave when viewed in the direction toward the tip 14 of the syringe plunger 10. The stem extends orthogonally from a the ‘bottom’ face of the base 20a, the proximal end of the stem 12 being located substantially centrally on the base 20a. The bottom face of the base 20a, i.e. that facing the stem 12, is provided with a plurality of protuberances or bumps 24 to form a frictional surface. It will be appreciated, however, that other methods of forming frictional surface on the underside of the base 20a could be used. A side wall 20b extends (integrally) from each opposing end edge 22b of the base 20a, the side walls 20b ‘meeting’ at a generally central apex 26 located furthest, and spaced apart, from the proximal end of the stem 12. The side edges 22a of the base 20a of the thumb loop 20 curve (laterally) outwardly, such that the width of the base 20a increases from each end edge 22b to a maximum at a central location along the length of the side edges 22a. The maximum width of the base 20a of the thumb loop 20 is thus greater than the width of the side walls 20b, which are of uniform width substantially equal to the width of the end edges 22b of the base 20a, as can be seen most clearly in Figure 1B of the drawings. Referring now to Figures 2A, 2B and 2C of the drawings, another example syringe plunger 30 once again comprises an elongate stem 12 with a screw-threaded tip 14 at its distal end. However, in this case, the integral thumb loop 32 at the proximal end of the stem 12 comprises a generally oval base 32a having a bottom surface from which the stem 12 extends and an opposing top surface. The base 32a is slightly concave (when viewed from the top of the syringe plunger 30, toward its tip 14). The thumb loop 32 further comprises a generally inverted U-shaped handle member 32b, the ends of which are coupled to the top surface of the base 32a, adjacent respective opposing ends thereof. Once again, a plurality of integral protuberances 34 are provided on the bottom surface of the base 32a. Referring to Figures 3A, 3B and 3C of the drawings, another example syringe plunger 40 once again comprises an elongate stem 12 having, at its distal end, a screw-threaded tip 14 for receiving thereon a seal (not shown). The integral thumb loop 42 at the proximal end of the stem 12 comprises a substantially oval base 42a that is concave (when viewed from the ‘top’ of the syringe plunger 40 towards its tip 14). However, in this case, the thumb loop 40 further comprises a generally circular member 42b that is integrally coupled, generally centrally, to the top (concave) surface of the base 42a. Referring to Figures 4A, 4B and 4C of the drawings, yet another example syringe plunger 50 once again comprises an elongate stem 12 having, at its distal end, a screw-threaded tip 14 for receiving thereon a seal (not shown). The integral thumb loop 52 provided at the proximal end of the stem 12 is similar, in many respects, to that of the embodiment described with reference to Figures 1A, 1B and 1C. Thus, the thumb loop 52 comprises a generally rectangular base 52 that has parallel opposing end edges 54b and the side edges 54a curve or bow outwardly, such that the width of the base at its centre is greater than the width of the end edges 54b. In this case, however, the base 52 is curved about the lateral axis, such that the base 52a is concave when viewed from the ‘top’ of the syringe plunger, towards its tip 14. A generally C-shaped handle portion 52b is integrally coupled to the base 52a so as to form a loop therewith, the width of the handle portion 52b being substantially equal to the width of the end edges 54b of the base 52a. An example syringe according to the invention could include any of the syringe plungers illustrated in Figures 1, 2, 3 or 4. Referring now to Figure 5 of the drawings, an example syringe 100 comprises a generally tubular barrel 102 having an opening 104 at one end and narrowing to an open-ended tip 106 at the opposite end. An external finger flange 108 is provided around the opening 104, the width of the finger flange 108 being greatest on two diametrically opposing sides of the barrel 102. The syringe 100 further comprises a syringe plunger 10, such as that described and illustrated with reference to Figures 1A, 1B and 1C. A seal 110 is mounted on the screw-threaded tip (14 - Figure 1A) of the elongate stem 12, the diameter of the seal 110 being substantially equal to the inner diameter of the syringe barrel 20 It will be apparent to a person skilled in the art, from the foregoing description, that modifications and variations can be made to the described embodiments without departing from the scope of the invention as defined in the appended claims.

Claims

1. A syringe plunger for a syringe comprising a tubular barrel, open at one end and narrowing to an open-ended tip at the other end, the syringe plunger comprising an elongate stem having a tip at one end for receiving a seal thereon and an integral thumb loop at the other end thereof.

2. A syringe plunger according to claim 1, wherein said tip of said syringe plunger is screw-threaded.

3. A syringe plunger according to claim 1 or claim 2, wherein the thumb loop comprises a base having a bottom surface from which the stem extends orthogonally and substantially centrally, and an opposing top surface.

4. A syringe plunger according to claim 3, wherein said base is curved, so as to be generally concave when viewed from the top surface in the direction of said tip.

5. A syringe plunger according to claim 4, wherein said base is curved about its longitudinal axis.

6. A syringe plunger according to claim 4 or claim 5, wherein said base is curved about its lateral axis.

7. A syringe plunger according to any of claims 3 to 6, wherein a plurality of integral protuberances is provided on the bottom surface of the base.

8. A syringe plunger according to any of claim 3 to 7, wherein the base comprises a pair of opposing longitudinal side edges, said side edges being outwardly curved such that the width of the base at its centre is greater than that at its ends.

9. A syringe plunger according to any of claims 3 to 8, wherein said thumb loop is generally triangular with externally rounded comers, wherein a pair of side walls extend from respective end edges of the base to a rounded apex furthest from the proximal end of the stem.

10. A syringe plunger according to any of claims 3 to 8, wherein the thumb loop comprises a generally C-shaped wall, the ends of which are integrally coupled to the top surface of the base, adjacent the respective end edges thereof.11 .A syringe plunger according to any of claims 3 to 8, wherein said thumb loop comprises a generally circular or oval loop member that is integrally coupled, generally centrally, to the top surface of the base.

12. A syringe plunger according to any of the preceding claims, wherein the elongate stem has one or more external longitudinal grooves therein.

13. A syringe comprising a tubular barrel that is open at one end and narrows to an open-ended tip at the other end, said open-ended tip being configured to receive5 thereon a hypodermic needle, the syringe further comprising a syringe plungeraccording to any of the preceding claims, slidably mounted in said barrel, and having a seal coupled to the tip of said stem, the diameter of said seal being substantially equal to the inner diameter of the tubular barrel.Application No: GB2309381.8Examiner:Mr Geraint DaviesClaims searched: 1-13Date of search: 7 November 2023Patents Act 1977: Search Report under Section 17Documents considered to be relevant:Category Relevant to claims Identity of document and passage or figure of particular relevance X 1-13 US 2015 / 238698 Al (PERRY) See entire document, noting particularly paragraph [0028] X 1-13 US 3487834 A (SMITH) See entire document, particularly column 5, lines 46-49 X 1-13 US 3316909 A (COWLEY) See entire document, particularly column 2, lines 10-13 v A 1-13 US 2022 / 355039 Al (MERSON) See entire document, particularly Figures 52-54 ¶graph [0076] X 1-13 US 2018 / 078705 Al (ALAMAT) See entire document, particularly paragraph [0019]Categories:X Document indicating lack of novelty or inventive step A Document indicating technological background and / or state of the art. Y Document indicating lack of inventive step if P Document published on or after the declared priority date but combined with one or more other documents of before the filing date of this invention. same category. & Member of the same patent family E Patent document published on or after, but with priority date earlier than, the filing date of this application.Field of Search:www.gov.uk / ipoInternational Classification:Subclass Subgroup Valid From A61M 0005 / 315 01 / 01 / 2006 A61M 0005 / 178 01 / 01 / 2006www.gov.uk / ipo

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