MX2008006952A - Cutting element for a retracting needle syringe - Google Patents

Abstract

A cutting element for a retracting needle syringe (20) having a plunger (23) with a cuttable distal end and a spring biased needle (83) held by a cuttable support. A cutting element (43) capable of cutting the cuttable distal end and the cuttable support includes a body portion (44) having a proximal end (45), a distal end (46), a side wall (47) therebetween and a passageway (50) therethrough. The distal end (46) of the body portion (44) includes a cutting edge (48) and a raised distally projecting tapered cutting tooth (51) having distally converging edges (52). At least one tooth edge includes a sharp side wall (55) for cutting the distal end of the plunger and the needle support.

Description

CUTTING ELEMENT FOR A SYRINGE WITH RETRACTABLE NEEDLE FIELD OF THE INVENTION [0001] The present invention relates to syringe and needle assemblies. More specifically, the present invention relates to a cutting element for a syringe and needle assembly having a structure that allows withdrawal of the cannula from the needle to the body of the syringe after use. BACKGROUND [0002J In recent years, a greater concern has been developed regarding the transfer of the disease, infection and the like to users of syringes and to health professionals who accidentally, or through negligent manipulation, are pricked with hypodermic needles. while discarding the used hypodermic needle. In many hospital areas, where cannula products with needles are used, waste containers are provided in such a way that a syringe or other cannula product with a needle can be immediately discarded in a secure rigid container. However, there are areas of medical practice, such as emergency rooms, where waste containers may not be readily available or impractical, and where products that have self-contained safety features are desirable. In theory, after using said syringe to inject medication or for another purpose, a safety device contained in the syringe or needle assembly is activated to prevent further contact with the sharp tip of the needle. One type of safety syringe includes a structure that allows removal of the hypodermic needle from the syringe body to minimize the possibility of subsequent contact with the sharp tip of the needle. [0003] The prior art includes syringes with a retractable needle that include a spring-loaded needle assembly that is held in place during normal use of the syringe assembly and a hollow piston rod that is sealed during normal use of the syringe assembly. syringe, so that medication or other liquids can not enter the cavity of the piston rod. These syringes have to have a structure that allows releasing the spring-loaded needle and the opening of the cavity of the piston rod, so that the needle can enter the cavity of the piston vap- lia after using the syringe for its intended use. To function properly, the cavity of the piston rod must be sealed so that the medication can not enter the piston rod during use. This seal must sometimes withstand high hydraulic pressures when a relatively viscous medication is injected through small needles and still be able to be easily unsealed and allow access by the needle assembly. Likewise, the needle assembly must be firmly held in place by the injection forces and still be disengaged, so that it can be retracted into the syringe body and the piston rod. Some of the syringes with retractable needle of the prior art try to solve these problems by having a leak-proof physical structure to keep the needle loaded with spring in position and to seal the end of the hollow piston rod. Upon completion of the injection process, an additional force directed distally to the piston is applied, causing an internal cutting element to cut the end of the hollow piston rod and the spring loaded needle holder. In some embodiments, the prior art retractable syringe cutter cuts in a proximal direction the spring-loaded needle mount bracket and then the distal end of the plunger rod. In both cases, this allows the spring loaded needle to enter the piston cavity, helping to keep the user safe from accidental needlesticks. [0004] Prior art syringe retraction syringes that rely on dislodging elements or the breaking of fragile barriers that will allow the spring-loaded needle to enter the piston, may require a wide range of forces to disengage the spring loaded needle. The retractable needle syringes with the cutter have an inherent advantage of being able to be produced so that the forces needed to activate the retractable needle are more consistent from syringe to syringe. [0005] The present invention is directed to an improved cutting element for a syringe with retractable needle to obtain syringe-to-syringe activation forces even more consistent and, if desired, lower activation forces. COMPENDIUM OF THE INVENTION [0006] a cutting element for a syringe with retractable needle having a piston with a cuttable distal end and a spring-directed needle maintained in a state energized by a cuttable support. The cutting element is capable of cutting the cuttable distal end of the piston and the cuttable support. The cutting element includes a body portion having a proximal end, a distal end and a side wall therebetween defining a longitudinal axis and a passageway therethrough. The distal end of the body portion includes a cutting edge and a raised conical tooth projecting distally and distally converging edges. At least one edge of the tooth includes a sharp side to cut the distal end of the piston and support. [0007] The tapered side wall may include a beveled edge. The cutting element may include a plurality of cutting teeth that may not be equally spaced around the distal end of the body portion. The converging distal edges of the cutting tooth may be found to form a distally directed point or not to be found and to define an edge directed distally at the distal tip. [0008] The cutting element can be configured in such a way that the cutting teeth include two sharp sides for cutting. The cutting teeth may be separated by concave cutting edges that run along the distal end of the body portion. [0009] For cutting elements having two or more teeth, the cutting edges between the cutting teeth may be approximately at the same height when measured along the longitudinal axis, or the cutting edges may be at different heights when measured at along the longitudinal axis of the cutting element. [0010] For cutting elements having two or more teeth, the distal tips of each cutting tooth may be approximately at the same height when measured along the longitudinal axis, or the distal tips may be at different heights when miae along the longitudinal axis the cutting element. [0011] The body portion of the cutting element can have a cylindrical shape. In addition, the cutting element can be configured in such a way that it has three teeth or four teeth. [0012]. The cutting element is desirably made of metal and preferably made of stainless steel. [0013] In another embodiment of the present invention, there is provided the cutting element for a syringe with retractable needle having a piston with a cuttable distal end and a spring directed needle held in a state energized by a cuttable support. The cutting element is capable of cutting the cuttable distal end of the piston and the cor- tileable support. The cutting element includes a cylindrically shaped sheet metal body portion having a proximal end, a distal end and a side wall between them defining an axis. longitudinal and a way of passage through it. The distal end of the body portion includes a beveled cutting edge and at least three (3) distally projecting tapered cutting teeth having a distal tip and distally converging beveled cutting edges that meet to form a point directed distally at the tip distal to cut. The bevelled cutting edge of the distal end of the body portion has a concave shape in the spaces between the teeth, which are spaced substantially equally around the distal end of the body portion. BRIEF DESCRIPTION OF THE DRAWINGS [0014] Fig. 1 is a perspective view of a syringe with retractable needle. [0015] FIG. 2 is an exploded perspective view of the syringe with retractable needle of FIG. 1. [0016] FIG. 3 is a cross-sectional view of the syringe with retractable needle of FIG. 1 taken along line 3 -3. [0017] FIG. 4 is an enlarged cross-sectional view of the outer central part of the retractable needle assembly [0018] FIG. 5 is an enlarged cross-sectional view of the inner central part of the retractable needle assembly. [0019] Fig. 6 is an enlarged cross-sectional view of the retractable needle assembly. [0020] Fig. 7 is an enlarged cross-sectional view of the distal end of the body of the syringe. [0021] Fig. 8 is a cross-sectional view of the distal end of the syringe with retractable needle of Fig. 1 illustrating the syringe after discharging the liquid contained therein. [0022] Fig. 9 illustrates the syringe of Fig. 8 when the proximal and distal portions of the plunger rod have been separated and the cutting element has cut the plunger y. the inner central part. [0023] Fig. 10 illustrates the syringe of Fig. 9 when the cutting element has completely cut the inner central part and the needle has retracted to the piston. [0024] FIG. 11 is a perspective view of a prior art cutting element for syringe with retractable needle. [0025] The I ig. 12 is a side elevational view of the cutting element of FIG. 11. [0026] FIG. 13 is a side elevational view of the cutting element of the present invention. [0027] Fig. 14 is a perspective view of the distal end of the cutting element of FIG. 13. [0028] FIG. 15 is a perspective view of the distal end of a preferred cutting element for a syringe with retractable needle of the present invention. [0029] FIG. 16 is a perspective view of the distal end of an alternative cutting element of the present invention. [0030] FIG. 17 is a perspective view of the distal end of another alternative cutting element of the present invention. [0031] FIG. 18 is a side elevational view of the distal end of yet another alternative cutting element of the present invention. [0032] FIG. 19 is a side elevational view of the distal end of another alternative cutting element of the present invention.

DETAILED DESCRIPTION [0033] Although this invention is satisfied by embodiments in many different forms, preferred embodiments of the invention are shown in the drawings and will be described in detail herein, with the understanding that the present description is to be considered as exemplary of the principles of the invention and is not intended to limit the scope of the invention to the illustrated embodiments. The scope of the invention will be measured by the appended claims and their equivalents [0034] Referring to Figs. 1-17, a syringe with maneuverable retractable needle 20 includes a retractable needle assembly 21, a syringe body 22 and a piston 23. The body includes an interior surface 25 defining a chaya 27, an open proximal end 28 and a distal end 29 including a cylindrical collar 31 having an outer surface 32 and an internal surface 33. [0035] The piston is positioned so that it can slide in a fluid-tight gear with the body's surface. The piston preferably includes a proximal portion 37 having a distal end 38 with an elongated cavity 39 therein.

[0036] A cutting element 43 is located at the distal end 38 of the proximal portion of the piston 23. The cutting element 43 includes a body portion 44 having a proximal end 45, a distal end 46, a side wall 47 therebetween defining a longitudinal ee 49 and a through path 50 therethrough. The distal end 44 includes a cutting edge 48 and at least one raised conical cutting tooth projecting distally 51 and having a distal tip 53 and distally converging edges 52. At least one edge of the tooth includes a sharp sidewall 55. The element The cutting of the tooth is an important feature of the present invention that offers advantages over prior art cutting elements having a flat cutting edge perpendicular or at an angle with respect to the longitudinal axis of the cutting element. This advantage will be discussed in more detail here below. As best illustrated in Fig. 13, the distal tip 53 of each of the cutting teeth is approximately at the same height when measured along the longitudinal axis, as indicated by the letter B. In addition, the cutting edges 48 may or may not be at the same height when measured along the longitudinal axis. In this embodiment, the cutting edges 48 are substantially at the same height, as indicated by the letter A, when measured along the longitudinal axis. [0037] A hollow distal portion 65 of the piston 23 is connected which can be released to the proximal portion 37 and is capable of telescopic movement with respect to the proximal portion. A cover member on the dhal portion seals a distal end 67. In this embodiment, the cover member is the plunger 70. It is preferred that the cover member be made of an elastomeric material selected from the group of thermoplastic elastomers. , natural rubber, synthetic rubber and their combinations. The cover element may also be thermoplastic or a combination of thermoplastic support material and elastomeric material. [0038] The retractable needle assembly 21 includes an outer central portion 71 having a proximal end 73, a distal end 74 and a passageway 75 therethrough. The retractable needle assembly also includes an inner central portion 76 having a proximal end 77, a distal end 79, and a conduit therethrough 80. The inner central portion includes an inner portion 81 and a securable outer portion 82 connected to the portion internal The outer, shorttable portion of the inner central portion is connected to the outer central portion 71. The distal end 79 of the inner central portion is smaller than the passage 75 of the outer central portion at the distal end 74 and is accessible from there and preferably it projects distally out of it. [0039] A needle cannula 83 having a dds-tal end 85, a proximal end 86 and a light 87 therethrough. The proximal end of the cannula is connected to the distal end 79 of the internal central part, such that the light is in fluid communication with the conduit 80 of the internal central part. The distal end of the cannula preferably includes a pointed or sharp distal tip. [0040] An energized spring is contained between the external and internal central parts and in this preferred embodiment the energized spring is a compressed cylindrical propeller spring 88. Various types of springs and elastomeric materials and the like can be used to obtain a force of impulse between the inner and outer central parts, the propeller being merely representative of these many possibilities, all of which are within the scope of the present invention. A cyclical helical spring is preferred because of its compact size and the ability to easily design the spring to obtain the forces necessary for proper operation of the retractable needle assembly. [0041] During assembly, the cylindrical propeller spring is placed on the inner portion of the inner central part and then the distal end of the spring is placed on the outer central part and the inner and outer central parts are moved toward the another to compress the spring and close them together through the accron of the annular closing projection 78 on the inner central part and the annular closing recess 72 in the outer central part. When the inner central part and the outer central part are joined, by compressing the cylindrical propeller spring, the annular closing projection on the inner central part strikes in the closing recess, annular 72 in the outer central part. The projection and the recess have a form such that much less force is required to mount the components than to reverse the process, thus allowing a permanent closed condition in which the central central part and the outer central part are inseparable during the conditions normal operation. There are numerous ways to connect the inner and outer central part and the stroke adjustment arrangement shown here is merely representative of all these methods, which fall within the scope of the present invention. In particular, adhesives, separate metal closure clamps, ultrasonic welding, ripple, internally molded closure structure and the like can be used to hold the inner central part and the outer central part together. [0042] A preferred way to connect the needle cannula to the retractable needle pocket is to place the proximal end of the needle cannula at the distal end of the conduit 80 of the inner central part. An enlarged or irregular portion 84 at the distal end of the conduit 80 provides a space for the adhesive 89 to be placed around the exterior of the needle cannula after being placed in the conduit. [0043] The retractable needle assembly also includes means for connecting the outer central part to the collar of the syringe body. In this embodiment, the connecting means includes a structure that allows an in-sartable gear between the collar and the outer central part. In this preferred embodiment, the structure for the ensar-table gear includes at least one thread 90 in the passageway 75 of the external central part 71 and at least one thread 34 in the outer surface 32 of the cylindrical collar. Thus, the assembly of The needle, in this embodiment, is connected so that it can be removed from the body. This feature allows flexibility to exchange needle and syringe assemblies to obtain a needle and syringe combination of appropriate size for the desired drug type and injection site. In addition, the structure of this embodiment allows for the installation and removal of the needle assembly from the body using the same movements required for the installation and removal of a standard hypodermic needle from a standard hypodermic syringe., so that no additional training is required for the health worker. [0044] The structure for the ensartable gear between the collar and the outer central part can include a wide variety of threaded or bayonet type structures, including a thread on the external surface of the collar and a threaded projection on the surface The outer central part will follow the thread of the collar when the central part is screwed on the collar. This structure is similar to the well-known combinations of luer-type needle assembly and closure syringe, where the collar of the syringe has a thread on its inner surface and the mounting of the needle has two projections directed outward into the base of its central body to allow the central part to follow the threads of the collar when it is screwed on the luer tip and the collar. In addition, the inside of the collar may be threaded on the outside of the outer central part and may have threaded parts. [0045] It is also within the scope of the present embodiment that we included "beads to connect the outer central part to the collar, which is permanent rather than windable so that it can be retrieved. For example, the outer central part may be attached to the collar using adhesive or ultrasonic welding, retaining clamps or a one-way adjustment arrangement that makes the assembly unusable under normal use. The structures are within the scope of the present invention. [0046] It should be noted that the assembly of the needle need not be removable or independent of the body. It is possible to optimize the elements of the body and the assembly of the needle to reduce the number of parts and achieve a permanently attached needle assembly.

[0047] To help prevent leakage, this embodiment includes a conical cylindrical surface 91 on the inner center portion 76 and a conical cylindrical surface 35 on the inside of the cylindrical collar 31 of the body. When the retractable needle assembly meshes with the body collar, the conical cylindrical surface 35 of the collar meshes with the conical cylindrical surface 69 on the inner center portion to seal the interface between the center part and the collar and prevent leakage during normal use. A gasket can also be used to seal some portion of the contact surfaces between the needle assembly and the body. In use, the retractable needle assembly of the present invention can be removably connected to the body of the needle. syringe 22 containing piston 23. A needle shield 93 can now be removed from the retractable needle assembly, thereby exposing the needle cannula for use. The syringe can be filled with shrinkable needle, using known methods for uses such as withdrawing an injectable liquid from a vial having a pierceable stopper. A syringe can then be used to inject liquid into a patient, an I.V. system, a catheter or other suitable device.

After injecting or otherwise supplying the liquid from the chamber's im- terror, the distal end of the plug will be in contact with the distal end of the body chamber, as best illustrated in FIG. 8. At this point, the user can apply additional distally directed axial force to the proximal end of the piston through the proximal stalk 41 to send the plug to the distal end of the body chamber and cause disengagement of the proximal portion 37 of the piston. with respect to the distal portion 65 of the piston. As the connection between the proximal portion of the piston and the distal portion of the piston is broken or exceeded, the proximal portion will move distally in the distal portion and along the forward cutting element of the body 43, such that its sharp distal end it will press and cut the plunger 70 and the inner central part between the inner portion 81 and the outer cutout portion 82, as best illustrated in FIG. 9. The application of a force directed distally to the piston that causes the release element to completely cut out the inner central part will allow the re-sorte to urge the inner portion of the inner central part together with the needle cannula toward the elongate cavity of the piston, as best illustrated in Fig. 10. The used needle cannula is now contained safely in the syringe assembly and ready for safe disposal. [0049] In this embodiment, the releasable connection between the proximal portion 37 of the piston and the distal portion 65 of the piston that allows relative telescopic movement between the two portions of the piston is provided by a stroke adjustment arrangement between the proximal portion of the piston. piston and the distal portion of the piston. In particular, an annular projection 68 on the inside of the proximal end of the distal portion 65 of the piston meshes with an annular groove 40 at the proximal end of the proximal portion 37 of the piston. When sufficient axial force is applied, the annular projection 68 disengages from the annular groove 40, allowing the distal end of the release element to cut the plunger and the inner central part between the outer cutout portion and the inner portion. There are numerous structures and. aterials and elements that can provide a releasable connection between the proximal and distal portions of the piston, the structure shown herein being merely representative of the many possibilities, all of which are within the scope of the present invention. In particular, any combination of projections and / or incoming and / or disconti-nuities in the proximal portion and in the distal porch can achieve a srmrlar result. In addition, the connection can also be breakable.as well as disengageable, such as by using a fragile adhesive between the two elements or molding the elements as an integral structure containing a brittle plastic projection or projections that join the elements and can be broken with a force applied to the piston. a breakable connection can be made by connecting the elements with a longitudinal pin. A longitudinal pad may be made of plastic with one or more notches or tension concentrators suitably positioned to cause rupture at the desired force levels. A breakable connection can also be achieved in a similar manner to the stroke adjustment arrangement, but by di-pointing the various projections and recesses so that they fail to reach the desired voltage level. Furthermore, it should be noted that a one-piece piston is possible if the plunger is designed to deflect towards a fixed cutting element when an excess of force is applied to the piston. [0050] In Figs. 11 and 12, there is illustrated a cutting element of the prior art 143. The cutting element includes a proximal end 145, a distal end 146 and a side wall 147 therebetween. The distal end 146 further includes a cutting edge 148. The cutting elements of the prior art are essentially cylindrical in shape and have a circular and planar cutting edge. The cutting edge is typically perpendicular to the longitudinal axis of the cutting element, such that the first contact of the cutting element is the inner surface of the plunger, or needle support element, depending on the design, and is a total circular contact. . When pressed against the plunger's interface, the cutting mechanism is one of "cutting", where the circular edge of the cutter penetrates directly into the internal surface of the plunger. There is no sliding component to the cut. This type of action requires a very sharp edge so that the load required to make the cut is minimal. A metal foil cutting element ", depending on the manufacturing process used in its formation, can be reasonably sharpened, however, a sharpening procedure after forming is required, in addition, the cutter is hardened so that the very thin edge does not Deformed during the cutting process Contact cutters tend to experience a wider range of shear forces possibly associated with dimensional and material variations and the sharpness of the cutting element, forming the planar cutting edge at an angle with respect to the longitudinal ee can reducing the cutting force cutting component [0051] The cutting element of the present invention offers a more robust design that does not necessarily require heat treatment or sharpening operations after forming and reduces the potential to have wide variations in forces required to get the cut of the plunger and the support structure of The needle The cutting mechanism of the cutting element of the present invention is not primarily "chopping", but rather one of "piercing and cutting". The geometry of the cutting edge of the cutting element of the present invention is not a circular plane, but rather a pointed crown geometry. By changing the mechanism by which the cutter operates, the cutting force is reduced and, therefore, a sharpening and a heat treatment after forming is needed. [0052] Fig. 15 illustrates the distal end of a preferred cutting element 243 of the present invention. The cutting element 243 includes a body portion 244 having a distal end 246 and a generally cylindrical side wall 247 defining a passageway 250 therethrough. The distal end includes the cutting edge 248 and three distally projecting tapered cutting teeth 251 having distally converging edges 252. In this embodiment, the three cutting lenses have a sharpened side wall in the form of beveled edges 257. Each cutting tooth includes a cutting edge. distally directed tip 258. The cutting teeth in this embodiment are spaced substantially equally around the distal end of the body portion and are separated by concave cutting edges 261, that is, that the cutting edge has a concave shape in the spaces between the cutting teeth. [0053] The pointed geometry of the teeth, together with the carved tip profile of each of the tips, creates an initial contact against the white surface with a very low surface area. When a force is applied, the load divided by the surface area defines the penetration voltage. Since the surface area is close to zero, the penetration voltage is very high and is capable of penetrating a target with only a very small load in relation to the cutting elements of the prior art. Once the penetration has been established, the sharp bevelled edges of the cutting teeth slice the white material rather than chop it. The applied force is, therefore, managed at a greater distance along the longitudinal axis, thus requiring less force to perform an equivalent job Near the end of the cut, the white material gathers between the roots of the cutting teeth and the The final portion of the cutting action certainly becomes "chopped", but the amount of material that remains is relatively small, so the force required to complete the cut is minimized. [0054] The cutting element of the present invention can be adapted to provide a series of different sensations while the cut is made based on the number of cutting edges, the depth, the teeth, the shape of the tips, the shape of the roots between the teeth and by the formation of a carved edge on the profile of each cutting tooth. Based on these variations, you can produce a very soft feeling, a very hard feeling or countless intermediate sensations. [0055] Fig. 16 illustrates an alternative cutting element of the present invention. In this embodiment, the cutting element 343 includes a body portion 344 having a distal end 346 and a generally cylindrical side wall 347 defining a passageway 350 therethrough. The distal end includes the cutting edge 348 and four distal cutting teeth 35 of distal projection 351 having distally converging edges 352. In this embodiment, the four cutting teeth have a sharp side wall in the form of beveled edges 357. Each cutting tooth includes a tip directed distally 358. The cutting teeth in this embodiment are spaced substantially equally around the drstal end of the body porch and are separated by concave cutting edges 361, ie, the cutting edge is concave in the spaces between the sharp teeth. [0056] Fig. 17 illustrates another alternative embodiment of the present invention. In this embodiment, the cutting element 443 includes a distal end 446, a side wall 447 and a passage 450 through the cutting element. The cutting element in this embodiment includes six raised distally projecting cutting teeth 451 having distally converging edges 452 terminating at a distally directed cutting edge 459. In this embodiment, the edges of the six cutting teeth have side walls tapered in the shape of beveled edges 457. The distally directed cutting edge 459 also preferably includes a beveled cutting surface 463. The cutting edge directed distally may be desirable for a cutting tip in situations where it is desired that the force required to initiate the cutting be greater than the cutting force. Posrble with the pointed tooth pointed. [0057] As indicated hereinabove, near the end of the cut the white material contacts the cutting boides between the cutting teeth, where the final portion of the cutting action becomes a "cut" The amount of material The remaining force is relatively small, so the force required to complete the cut is minimal.The force is minimized even further with the concave cutting edges that further reduce the amount of material to be cut using a chopping action. The strength of this final chopping action can also be reduced by staggering the cutting edges as illustrated in the embodiment of Fig. 18. In this embodiment, the cutting element 543 includes a distal end 546, a side wall 547 and a passageway therethrough. The cutting element in this embodiment includes six raised distally projecting tapered cutting teeth 551 having distally converging edges 552 terminating at a distal tip 553. The cutting teeth in this embodiment are spaced substantially uniformly around the distal end of the portion. of body and are separated by concave cutting edges 561. At least two of the cutting edges between the cutting teeth are at different heights when measured along the longitudinal axis of the cutting element. In this embodiment, at least one cutting edge is located at a distance C, measured along the longitudinal axis, while at least one other cutting edge is located at a different distance D when measured along the longitudinal axis. Consequently, the final cutter action of the cutter is stepped to reduce the required cutting force. In this embodiment, a cutting edge yes and one are not at a distance C and the cutting edges in between are at a distance D. [0058] FIG. 19 illustrates another alternative embodiment of the present invention. This embodiment is similar to the embodiment of Fig. 18, except for the fact that the force required for the initial cutting action is reduced by staggering the distal tips of the cutting teeth. In this embodiment, the cutting element 643 includes a distal end 646, a side wall 647 and a passageway therethrough. A cutting element in this embodiment includes six tapered distally projecting cutting teeth 651 having distally converging edges 652 terminating at the distally directed tip 658 at the distal end. The cutting teeth in this embodiment are substantially equally spaced around the distal end of the body portion and are separated by concave cutting edges 661. At least two of the cutting edges between the cutting teeth are at different heights when measured at length of the longitudinal axis 649 of the cutting element. In this embodiment, at least one cutting edge is located at a distance E, measured along the longitudinal axis, while at least one other cutting edge is located at a different distance F, when measured along the longitudinal axis. In addition, at least two of the distally directed tips 558 are at different heights when measured along the longitudinal axis of the cutting element. In this embodiment, at least one distally directed tip is located at a distance H, measured along the longitudinal axis, while at least one other cutting edge is located at a different distance J, when measured along the longitudinal axis. Accordingly, staggering the distally rigid tips 658 reduces the cutting force during this cutting phase by not having to initiate all the cutting action simultaneously. [0059] It is desirable to make the metal cutting element, such as a metal sheet and preferably stainless steel. However, any material suitable for cutting the components of the syringe in question can be used to form the cutting element, such as plastic materials, ceramics and the like, all of which are within the scope of the present invention. the preferred embodiments of the present invention have a cylindrical side wall; however, other shapes, such as elliptical or multi-sided, such as hexagonal, square and the like, are within the scope of the present invention and the illustrated cylindrical body portion is merely representative of these multiple possibilities. [0060] Other syringes with retractable needle, such as the syringe with retractable needle shown in US Pat. No. 6,432,087 Bl, operate in a manner similar to the syringe with retractable needle described herein, but contain, the cutting element at the distal end of the syringe plunger, with the cutting edge running in the proximal drreccron. In this type of syringe with retractable needle, after the injection, the user exerts a drilling force directed additionally to the piston, which causes the cutting element to cut the support structure which maintains the energized spring and the needle and then the distal end of the piston, to allow the spring to move the needle into the piston cavity. The present cutting element also intends to function in rows of this tripod.

Claims (22)

1. CLAIMS 1. A cutting element for a syringe with retractable needle having a piston with a cuttable distal end and a spring-directed needle maintained in a state energized by a cuttable support and wherein said cutting element is capable of cutting said distal end cuttable and said cuttable support, consisting of - a body portion having a proxi-mal end, a distal end and a side wall between them that defines a longitudinal axis and a passageway therethrough, the distal end of which includes an edge cutting and a conical cutting tooth of raised distal projection having a distal tip and converging edges, at least one edge of the tooth having a sharp side wall for cutting said distal end of said piston and said support.
2. 2. The cutting element for a syringe with retractable needle of claim 1, wherein said sharp side wall of said tooth includes a beveled edge.
3. 3. The cutting element for a syringe with retractable needle of claim 1, wherein said conical cutting tooth includes a plurality of cutting teeth.
4. 4. The cutting element of claim 3, wherein said distal tip of each of said cutting teeth is ap- propriate thereto to the Louvre when measured along said longitudinal axis. The cutting element of claim 3, wherein at less two of said distal tips of said cutting tooth are at different heights when measured along said longitudinal axis 6 The cutting element of claim 3, wherein each of said cutting edges between said cutting teeth is approximately same height when measured along said longitudinal axis 7 The cutting element of claim 3, wherein at least two of said cutting edges between said cutting teeth are at different heights when measured along said longitudinal ee. cutting blade of claim 3, wherein at least two of said distal tips of said cutting teeth are at different heights when measured at of said longitudinal axis and at least two of said cutting edges between said cutting teeth are at different heights when measured along said longitudinal axis 9. The cutting element for a syringe with retractable needle of claim L, wherein said distantly convergent edges of said cutting tooth meet to form a tip directed distally at said distal end. The cutting element for a syringe with retractable needle of claim 3, wherein said plurality of cutting teeth are substantially uniformly spaced around said distal end of said body portion. The cutting element for a syringe with retractable needle of claim 3, wherein said plurality of teeth are separated by concave cutting edges that run along said distal end of said body portion. The cutting element of claim 11, wherein said concave cutting edges include a beveled edge. The cutting element for a syringe with retractable needle of claim 3, wherein both edges of said tooth have a sharp side for cutting. The cutting element for a syringe with retractable needle of claim 3, wherein both edges of the tooth have a sharp side for cutting and said plurality of teeth are separated by concave cut edges that run along said distal end of the tooth. -cha body portion. 15. The cutting element for a syringe with retractable needle of claim 1, wherein said body portion has a cylindrical shape. 16. The cutting element for a syringe with retractable needle of claim 3, wherein plurality of cutting dientes consists of three (3) cutting edges. 17. The cutting element for a retrigger needle of claim 3, wherein said plurality of cutting teeth consists of four (4) cutting teeth. 18. The cutting element for a syringe with retractable needle of claim 1, wherein said body portion is made of metal. 19. A cutting element for a syringe with retractable needle having a piston with a cuttable distal end and a spring directed needle held in a state energized by a cuttable support and wherein said cutting element is capable of cutting said distal end. co-able and said cuttable support, consisting of: a cylindrically shaped body porch having a proximal end, a distal end and a side wall between them that defines a longitudinal axis and a passageway therethrough, the distal end of which includes a beveled cutting edge and at least three (3) distally projecting tapered cutting teeth having a distal tip and distally converging bevelled cutting edges for cutting said drone piston end and said needle holder, said beveled cutting edge being said concave cutting teeth. 20. The cutting element for a syringe with retractable needle of claim 19, wherein said cutting teeth have a substantially equal spacing around said distal end of said body portion. The cutting element for a syringe with retractable needle of claim 19, wherein said distally converging edges of said cutting teeth meet to form a tip directed distally at said distal end. 22. A cutting element for a retractable needle L.1 having a piston with a cut distal end and a spring directed needle held in a state energized by a cuttable support and where said cutting element is capable of cutting said distal end cuttable and said cuttable support, consisting of: a cylindrical sheet metal body portion having a proxmal end, a drstal end and a side wall between them defining a longitudinal axis and a passageway therethrough, the end of which Such a rincludes a beveled cutting edge and at least three (3) conical cutting teeth of distal projection having a distal tip and distally converging beveled cutting edges that meet to form a distally directed tip at said distal end to cut said end distal of said piston and said needle support, said bevelled cutting edge being between said cutting teeth of concave shape and being said cutting teeth are substantially uniformly spaced around said distal end of said body portion.