HK1243012A1 - Needle tip shielding device and catheter hub therefor - Google Patents

Abstract

A needle tip shielding device (100), comprising a base plate (101) with a hole extending there through from the proximal side of the base plate (101) to the distal side of the base plate, and at least one resilient arm (103) extending at an attachment point at said base plate (101) is provided. The resilient arm (103) has a resting state wherein a distal hook (104) of the resilient arm (103) will coincide with a straight imaginary line extending longitudinally through said hole (102) in the axial direction of said base plate (101). The resilient arm (103) comprises a knob (105) at its distal end, said knob (105) extending laterally from the resilient arm (103). The knob (105) is shaped with an outer curvature in the transversal plane (106) around an axis parallel to the central axis of the needle tip shielding device (100), and said knob (105) is shaped with an outer curvature in the midsagittal plane (107) around an axis perpendicular to the central axis of the needle tip shielding device (100).

Description

Needle tip shielding device and catheter hub

Technical Field

The present invention relates to a needle tip shielding device for a catheter instrument comprising a needle tip shielding device, a needle hub and a catheter hub, wherein the needle tip shielding device is arranged on a needle in the catheter hub for automatic safety shielding of the needle after it has introduced a catheter tube into the vascular system of a patient.

Background

In medical technology, for introducing catheters, it is widely known to apply a pointed hollow needle mounted in a flexible catheter tube to the clinic. In such medical devices, the catheter tube tightly surrounds the needle, allowing the needle to slide and nest along the length of the catheter tube. Before use, the tip of the needle is extended slightly out of the opening of the catheter tube so that it can easily pass through the skin. When the needle penetrates the skin, the distal end of the catheter tube is simultaneously placed within the intended target body cavity of the patient, for example the interior of a blood vessel such as a vein. The needle then has completed its task of assisting in the introduction of the catheter and is pulled back through the catheter. When the needle is released, the catheter is placed in its predetermined mode of operation, including, for example, periodic administration or infusion of a medication in fluid or liquid form, collection of a blood sample, etc., for an extended period of time.

However, an unprotected release needle can pose a serious health hazard due to the possibility of contamination by infectious agents, such as from the patient's blood or other bodily fluids, coupled with the inherent ability of the needle tip to readily penetrate the skin. Thus, medical personnel handling the delivery needle may develop a corresponding disease, such as AIDS or hepatitis, if the skin of the medical personnel is inadvertently brought into contact with the delivery needle. In order to circumvent or mitigate the health hazards associated with such release needles, amongst other things, there has been a constant effort to develop various types of needle tip protectors, and in particular an automatic needle tip protector which may be praised as "foolproof".

Patent EP 1003588 discloses a safety IV catheter comprising a resilient spring clip normally positioned in the catheter hub. The needle of the safety IV catheter passes through the hole in the spring clip, allowing the needle to move axially. When the needle is in the advanced position, i.e. when the safety IV catheter is ready for use, the presence of the needle forces the spring clip components into a position that locks these components into the catheter hub, thereby avoiding movement of the spring clip relative to the catheter hub. When the needle is withdrawn to pass the tip through these components, the spring clip snaps into place, thereby preventing the needle tip from being touched. At the same time, the spring clip member, previously locked inside the catheter hub, is released from this position, thereby allowing the spring clip to move relative to the catheter hub. As the needle is withdrawn further, a device, such as a slot or crimp, provided on the needle head may lock the spring clip onto the needle head, thereby causing the spring clip to be ejected from the catheter hub in a manner positioned on the needle head.

For various reasons, including practical, economic and technical reasons, the spring clips described above and similar commercially available variants are currently made of metal, as well as of plastic material for the catheter hub. The combined use of these materials in this application includes the following disadvantages: as the metal spring clip scrapes the inside of the plastic catheter hub, microscopic plastic chips and metal particles, for example, are generated when the needle is withdrawn to dislodge the former from the latter. These debris and particles can be easily flushed into the bloodstream of a patient during normal use of the corresponding catheter, thereby posing a serious health hazard to the patient. This is especially true when the spring clip needs to travel over a bump or the like in the cavity of the catheter hub, on which the metal spring clip should be placed in the retaining position until the needle tip passes the distal part of the metal spring clip, causing the metal spring clip to be released. Another disadvantage of this and similar spring clips of safety IV catheters is that scraping vibrations are generated when the needle slides through and over the spring clip during withdrawal. Such scraping vibrations caused by the sliding of metal on metal can be clearly heard and felt, making the patient extremely uncomfortable and worried about, and in a situation of discomfort and exposure, a great concern.

For these reasons, attempts have been made to manufacture the spring clip from materials that do not damage the lumen of the catheter hub. WO2013162461 discloses a spring clip of plastic material that interacts with the catheter hub lumen through its base plate. However, since the tongues of the spring clip base plate will be in tension when arranged in the catheter hub, there is a risk that the base plate interacts too much with the catheter hub lumen.

If, instead, the spring clip is too loose to interact with the catheter hub lumen, the pulling of the needle shaft on the spring clip may cause the spring clip to release prematurely before the needle tip has passed through the distal portion of the spring clip. In fact, the spring clip does not protect the needle tip, constituting a serious health hazard, as the practitioner may desire that the needle tip be protected.

Therefore, it would be beneficial to develop a catheter device with a needle protection system which ensures a high product reliability while avoiding the release of e.g. microscopic plastic fragments.

Disclosure of Invention

Accordingly, the present invention preferably seeks to mitigate, alleviate or eliminate one or more of the above-identified deficiencies in the art and disadvantages singly or in any combination and solves at least the above mentioned problems by providing a needle tip shielding device comprising: a base plate having a hole extending therethrough from a proximal side of the base plate to a distal side of the base plate; and at least one resilient arm extending at a connection point on the substrate; wherein the at least one resilient arm has a rest state in which a distal hook thereof will coincide with a straight imaginary line extending longitudinally through the aperture in the axial direction of the base plate, the at least one resilient arm including a knob at a distal end thereof, the knob extending transversely from the resilient arm; wherein the knob is formed by an outer curvature in a transverse plane around an axis parallel to the central axis of the needle tip shielding device and the knob is formed by an outer curvature in a mid-sagittal plane around an axis perpendicular to the central axis of the needle tip shielding device.

A catheter instrument comprising such a needle tip shielding device is also provided.

Advantageous embodiments of the invention will become apparent from the appended claims.

Brief description of the drawings

The above and other aspects, features and advantages of the present invention will become more apparent from the following description of non-limiting embodiments thereof, given by way of example only and with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a spring clip needle tip shielding device;

FIG. 2 is a side view of the spring clip needle tip shielding device;

FIG. 3 is a front view of the spring clip needle tip shielding device;

FIG. 4 is a top view of the spring clip needle tip shielding device;

FIG. 5 is a cross-sectional view of the catheter assembly;

FIG. 6 is a partial cross-sectional view of a catheter assembly with a circumferential groove and a needle with a spring clip needle tip shielding device in an installed state;

FIG. 7 is a partial cross-sectional view of a catheter assembly having a circumferential groove and a needle having a spring clip needle tip shielding device in a relaxed state protecting the needle tip;

FIG. 8 is a partial cross-sectional view of a catheter assembly having a circumferential annular ridge and a needle having a spring clip needle tip shielding device in an uninstalled, untensioned state;

FIG. 9 is a partial cross-sectional view of a catheter assembly with a circumferential annular ridge and a needle with a spring clip needle tip shielding device in an installed state;

FIG. 10 is a partial cross-sectional view of a catheter assembly having a circumferential annular ridge and a needle having a spring clip needle tip shielding device in a relaxed state protecting the needle tip;

FIG. 11 is a perspective view, partially in cross-section, of a catheter assembly having two circumferential grooves;

FIG. 12 is a partial cross-sectional view of a catheter assembly having two circumferential grooves and a needle having a spring clip needle tip shielding device in a relaxed state protecting the needle tip;

FIG. 13 is a partial cross-sectional view of a catheter assembly having two circumferential grooves and a needle having a spring clip needle tip shielding device in an installed state;

FIG. 14 is a cross-sectional view of the needle assembly;

FIG. 15 is a cross-sectional view of a needle system including a needle assembly and a spring clip needle tip shielding device;

fig. 16 is a cross-sectional view of a catheter instrument including a spring clip needle tip shielding device, a catheter assembly and a needle assembly according to the present invention.

FIG. 17 is a perspective view of a catheter instrument.

Detailed description of the embodiments

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that those skilled in the art can practice the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Further, the terminology used in the detailed description of the particular embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. More specifically, the term "proximal" refers to a position or orientation of an object or object component that is closest to the user, i.e., clinician, and farthest from the patient receiving the IV catheter system during normal use of the IV catheter system disclosed herein. Similarly, the term "distal" refers to a position or orientation of an object or object component that is closest to the patient and farthest from the clinician during normal use of the IV catheter system disclosed herein. The term "lateral" refers to a direction that is offset from the central axis of the IV catheter system by at least a vector component that is perpendicular to the central axis of the IV catheter system with which the needle and catheter of the assembled IV catheter system coincide. Accordingly, the term "intermediate" refers to a direction toward the central axis of the IV catheter system such that it is at least a vector component perpendicular to the central axis of the IV catheter system, wherein the needle of the assembled IV catheter and the catheter system coincide with the central axis of the IV catheter system. The term "transverse plane" refers to a plane that divides the catheter system into proximal and distal portions defined by a transverse axis and an axis perpendicular to the central axis of the catheter. The term "midsagittal plane" refers to a vertical plane through the midline of the catheter system, defined by the central axis and the lateral axis of the catheter.

Fig. 1-4 show a needle tip shielding device 100, such as a spring clip needle tip shielding device 100, according to the present invention. The spring clip needle tip shielding device 100 comprises a base plate 101. The base plate 101 is provided with a hole 102 extending therethrough, i.e. from the proximal side to the distal side of the base plate 101. Preferably, the hole 102 is arranged in the center of the base plate 101, so that it is convenient to arrange the needle 302 through said hole 102, when the needle 302 is arranged according to the standby position of the catheter instrument 1000.

A first resilient arm 103 extends distally from a connection point on the base plate 101. Preferably, the connection points are located at the periphery of the substrate 101 for manufacturing reasons. At least one elastic arm 103 has a rest state from which it can be pushed into a tensioned state to create a free passage along the axial direction of the base plate 101 for the needle 302 through the hole 102. When the catheter instrument 1000 is in its standby position, the resilient arm 103 is in its tensioned state. When the resilient arm 103 is in said rest state, the resilient arm 103 is adapted to grip the tip of a needle 302 extending through the aperture 102. Thus, when the resilient arms 103 are in the rest state, any straight imaginary line extending longitudinally through the hole 102 in the axial direction of the base plate 101 coincides with the at least one resilient arm 103. This may be facilitated by providing the resilient arm 103 with a distal hook 104 at the distal end of the resilient arm 103. Thereby, the spring clip needle tip shielding device 100 may be arranged in the inner cavity 204 of the catheter hub 201, with the needle arranged through the hole 102, and with the resilient arm 103 placed in its tensioned state by the needle shaft.

The spring clip needle tip shielding device 100 is integrally made of a plastic material with good flexibility and tension maintaining properties, such as polycarbonate, to avoid scraping the inside of the catheter hub 201. The at least one resilient arm 103 is then dimensioned such that it can be bent into its tensioned state when the catheter instrument 1000 is in its standby position.

At least one resilient arm 103 is correspondingly provided with at least one knob 106. A knob 106 extends laterally outwardly from the resilient arm 103. The knob 105 is located at or near the distal end of the at least one resilient arm 103. In this manner, the knob 106 may flex slightly to facilitate the fit between the resilient arm 103 (i.e., the spring clip guard 100) and the catheter hub 200, and also to compensate for differences in the shape of the interior cavity 204 of the catheter hub 200.

By providing at least one knob 105 on the distal end of the resilient arm 103, the spring clip needle tip shielding device 100 will be reversibly locked in place in the catheter assembly 200 by the interaction between the knob 105 and the groove 205 or ridge 206 in the catheter assembly 200 when the at least one arm 103 is in tension. Once the arm 103 returns to the resting state, i.e. once the needle tip 305 is pulled out of the catheter 202 and into the needle tip shielding device 100, the needle shield 101 will clamp itself around the needle tip 305, and thus the at least one arm 103 of the needle shield 100 will return to the resting state. When this occurs, the knob 105 will release contact with the groove 205 or ridge 206 in the catheter assembly 200, thereby unlocking from the catheter hub 201 first when the needle tip 204 is safely protected.

The at least one knob 105 has an outer curved shape with an outer curvature in a transverse plane 106 around an axis parallel to the central axis of the spring clip needle tip shielding device 100. The external curvature in the transverse plane 106 ensures that interaction between the knob 105 and functional components (such as grooves or ridges) in the catheter hub 201 occurs without excessive deformation of the scraping knob 105, catheter hub 201 or grooves 205 or ridges 206. This also ensures a smoother and more consistent functioning of the needle clip shielding device. If the knob 105 includes sharp corners in the transverse plane, there will be several disadvantages evident during operation. The force during release of the needle shield from the catheter hub will concentrate on the sharp corner on the spherical protrusion 105, interacting with the catheter hub 201. With a low modulus of elasticity (polymer (PC))2300MPa or (LCP)7000MPa), the sharp corners of the lobes 105 can act as hooks until they deform or break (requiring a greater force) or bend (requiring a lesser force). Thus, this inconsistent nature would compromise the security function.

Furthermore, the at least one knob 105 has an outer curved shape, the outer curvature in the mid-sagittal plane 107 being around an axis perpendicular to the central axis of the spring clip needle tip shielding device 100.

The interior of the catheter hub 201 is rounded in the mid-sagittal plane, with a corresponding curved shape in the mid-sagittal plane 107 of the knob 105 spreading the interaction forces over a larger area. With the spring clip needle tip shielding device 100 and the catheter hub 201 made of a polymer with a modulus of elasticity (polymer (PC)2300MPa or (LCP)7000MPa), the large area interaction results in bending of the material without any constant deformation or scratching.

This becomes particularly evident for needle shields made from folded sheet metal (e.g. in EP 1003588) where the sheet metal is bent into a clip, which inherently results in a flat surface with sharp corners at the bending points. The polymeric body of catheter assembly 200 has a significantly lower modulus of elasticity (polymer (PC)2300MPa or (LCP)7000MPa)) compared to the modulus of elasticity (210000MPa) of the metal clamp). Thus, the sharp metal corners will not deform, but the surface of the catheter hub will be scraped by the hard metal clip during interaction.

Fig. 5-7 illustrate an example of a catheter assembly 200 that includes a catheter hub 201 and a catheter 202 extending distally from the catheter hub 201. The catheter 202 is hollow and tubular and is configured to receive a needle 101 shaft therein. Catheter assembly 200 may also be a catheter assembly for use with an open or closed catheter system.

The catheter 202 is made of a suitable polymeric material. The catheter hub 201 is also made of a suitable polymeric material, such as polypropylene or polyethylene, which is a cheap plastic material with good injection moulding properties. The hollow tubular structure of the catheter 202 provides an inner lumen 203, the inner lumen 203 being in fluid communication with the interior cavity 204 of the catheter hub 201; the internal cavity 204 is located at the proximal end of the catheter hub 201, and the proximal opening into the internal cavity 204 may terminate in a Luer fitting, such as a Luer lock or Luer slip lock, adapted to receive a line set, which in a known manner, delivers intravenous fluid to the patient. Thus, the catheter assembly 200 includes a catheter hub 201 and a catheter 202 extending distally from the catheter hub 201, the catheter 202 having a lumen 203 in fluid communication with an interior cavity 204 of the catheter hub 201.

Catheter 202 is secured within an axial passage in the distal hub by a sleeve received within the passage and the sleeve engages the proximal end of catheter 202. The channel communicates at its proximal end with an internal cavity 204, the internal cavity 204 also serving as a flash chamber formed within the catheter hub 201. The distal end of the catheter 202 may be tapered to facilitate introduction into the patient's blood vessel.

The inner cavity 204 of the catheter hub 201 may be provided with at least one circumferential groove 205 or ridge 206 on the wall of the inner cavity 204 of the catheter assembly 200.

As shown in fig. 6-7, at least one circumferential groove 205 extends radially from the interior cavity 204 into the wall of the catheter hub 201 about the central axis of the catheter assembly 200. The depth of the circumferential groove 205 is 0.05-0.1 mm. The slots 205 are located at the same distal distance from the proximal side of the catheter hub 201 as the distance from the proximal side of the base plate 101 to the knob 105 of the needle shield.

In the case of at least one circumferential ridge 206, as shown in fig. 8-10, the ridge 206 extends inwardly about the central axis from the wall of the catheter hub 201 into the interior cavity 204. The height of the circumferential ridge 206 is 0.05-0.1 mm. The ridge 206 is located at a distal distance from the proximal side of the catheter hub 201 that is shorter than the distance from the proximal end of the base plate 101 to the spherical protrusion 105 of the needle shield, e.g. 0.1-1mm shorter.

At least one groove 205 or ridge 206 interacts with at least one spherical protrusion 105 of the needle shield 100. The external curvature in the transverse plane 106 of the knob 105 ensures that interaction between the knob 105 and the groove 205 or ridge 206 occurs without excessive deformation of the scraping knob 105, the catheter hub 201 or the groove 205 or ridge 206. This also ensures a smoother and more consistent functioning of the needle clip shielding device.

When the spring clip guard 100 is received in the interior cavity 204 of the catheter hub 201, the spring clip guard 100 will be urged centrally and distally into the catheter hub 201. Once the needle shield 100 base plate 102 is fully inserted, the spring clip shielding device 100 reaches its inserted position. When the needle shield 100 is fully inserted, the knob 105 on the at least one arm 103 is positioned to interact with the at least one circumferential grass 05, as shown in fig. 3,4,5, 6. Similarly, in case the inner cavity 204 of the catheter hub 201 is provided with at least one circumferential ridge 206, the spherical protrusion 105 on the at least one arm 103 is located to interact with the catheter hub 200 when the needle shield 100 is fully inserted.

By providing at least one knob 105 on the distal end of the resilient arm 103, the knob 105 will be forced into contact with a groove 205 or ridge 206 in the catheter assembly 200 when the at least one arm 103 is in tension, and the spring clip needle tip shielding device 100 will be reversibly locked in place in the catheter assembly 200. When mounted in the catheter hub 201, the needle shaft 303 mounted by the spring clip guard 100 will exert a lateral pressure on the at least one resilient arm 103, pushing it outwards towards the catheter wall. Thus, the knob 105 will snap into the circumferential groove 205 or behind the ridge 206. This will protect the needle shield 100 from being inadvertently released from the catheter assembly 200 until the needle tip 304 has entered the safety of the needle shield 100. Once the needle tip 204 is pulled proximally out of the catheter 202 and into the needle tip shielding device 100, the needle shield 101 will clamp itself around the needle tip 305 and thus the at least one arm 103 of the needle shield 100 will return to the resting state. When this happens, the knob 105 will release contact with the groove 205 or ridge 206 in the catheter assembly 200, so that when the needle tip 204 is safely protected, the needle shield 100 will first unlock from the catheter hub 201, facilitating easy release of the protected needle from the catheter hub.

Fig. 6 shows the needle shield fully inserted into the interior cavity 204 of the catheter hub 201. Here, the knob 105 has snapped into a corresponding groove of the catheter hub 201. The interaction between the groove 205 and the knob 105 securely holds the needle shield 100 in the mounted position.

Fig. 7 shows the needle shield in the inserted position, in which the needle 302 is retracted to a position adjacent the hook 104 of the resilient arm 103, whereby the pressure of the needle on the resilient arm is released, allowing the resilient arm to move to the relaxed position.

Needle assembly 300 includes a needle hub 301 and a needle 302, wherein needle 302 extends distally from needle hub 301. The needle hub 301 may have an axial opening for receiving the proximal region of the needle 302. The needle 302 includes a needle shaft 303 and a needle tip 305, the needle tip 305 forming a distal point of the needle assembly 300. Conventionally, the needle hub 301 may be hollow and may include a flash chamber at its proximal end. Also conventionally, the needle 302 is housed within a hollow tubular catheter 202, the proximal end of which is concentrically fixed within the distal end of the catheter hub 201. At the distal end region of the needle shaft 303, the needle 302 has a bulge 304 and a needle tip 305. Thus, the needle assembly 300 includes a needle hub 301 and a needle 302 having a needle shaft 303, a protuberance 304, and a needle tip 305 extending distally from the needle hub 301.

The needle system 400 comprises a needle hub 301, a needle 302 and a spring clip shielding device 100 according to the present invention. The spring clip shielding device 100 is mounted on the needle shaft 303 and is located between the needle hub 301 and the needle boss 304.

Fig. 16 and 17 illustrate an exemplary IV catheter instrument 1000 according to the present invention, including a spring clip needle tip shielding device 100, a catheter assembly 200, and a needle assembly 300 according to the present invention. The safety IV catheter apparatus may also be an open or closed catheter system.

In the ready-to-use position of the catheter instrument 1000, the proximal end of the catheter hub 201 is closely and releasably received in the distal end of the needle hub 301 such that the needle tip 302 extends through the cavity 204, the channel, and distally over the catheter hub 201 and the catheter 202 such that the needle tip extends over the distal end of the catheter 202. Thus, in the ready-to-use position of the catheter instrument 1000, the needle hub 301 is connected at the proximal end of the catheter hub 201 and the needle shaft 303 is arranged in the lumen 203 of the catheter 202. In the ready-to-use position of the catheter instrument 1000, the needle hub 301 may be attached to the proximal end of the catheter hub 201 and the needle shaft 303 is disposed in the lumen 203 of the catheter 202.

In use, the distal tip of the needle 302 and the catheter 202 are inserted into a patient's blood vessel. The health care provider then manually places catheter 202 deeper into the blood vessel and then withdraws the needle by manually grasping and moving the proximal end of needle assembly 300. In the exemplary safety IV catheter instrument 1000, a fluid source to be administered into a patient's blood vessel is mounted on the Luer of the catheter hub 200 located in the proximal end of the cavity 204.

After the distal tip of the needle 302 and the catheter 202 have been inserted into the patient's blood vessel, the needle assembly 300 is moved proximally relative to the catheter assembly 200 and the spring clip needle tip shielding device 100. In accordance with the above, the spring clip needle tip shielding device 100 is held in the catheter hub 201 of the catheter assembly 200 by the interaction between the base plate 102 and the resilient arm 103. When the needle assembly 300 is moved proximally relative to the catheter assembly 200 and the spring clip needle tip shielding device 100, the needle 302 is also moved proximally relative to both. Once the needle tip travels proximally past the distal end of the resilient arm 103, such as the hook 104, the distal end of the resilient arm 103 may snap in front of the needle tip. The bump on the pin shaft then hits the substrate 102 because the bump 305 is sized and has a diameter slightly larger than the diameter of the through hole of the substrate 102. Furthermore, the bump has been positioned on the needle shaft and its distance from the needle tip largely corresponds to the distance between the base plate 102 and the distal end of the resilient arm 103, which allows the spring clip needle tip shielding device 100 to be fixed at the distal end of the needle 302 once the needle tip has moved proximally past the distal end of the spring clip needle tip shielding device 100, e.g. the hook 104. In this position, the spring clip needle tip shielding device 100 may be released from the catheter assembly 200 by overcoming the friction between the base plate 102 and the inner wall of the catheter hub 201, according to the above. The reversible interlocking of the interaction between knobs 105 and grooves 205 or ridges 206 in catheter assembly 200 will ensure that the needle shield is not released until the needle shield 300 is securely disposed over the needle tip 304 to inhibit and prevent accidental needle sticks, as shown in fig. 7, 10 and 12.

Fig. 11-13 show the structure in which the needle shield 100 is mounted on a needle, the needle shaft 206 extending through a hole in the base plate of the needle shield, the base plate being located at the proximal end and the two resilient arms 103 being located at the distal end. As shown in fig. 12 and 13, each resilient arm 105 of the needle shield 100 has a laterally extending knob 105 at the distal end of the resilient arm 103. Two corresponding slots 205 extend along the inner radius of the interior cavity 204 of the needle hub 201, transversely to the extension of the needle 302. The knobs 105 are located at different distances from the proximal end of the needle shield 100 and the distances correspond to the distance between the two grooves 205 and the proximal end of the catheter hub 200, respectively.

Fig. 12 shows the shield in the inserted position, in which the needle is retracted to a position adjacent the hooks 104 of the two resilient arms 103, whereby the pressure of the needle 302 on the resilient arms 102 is released, allowing the resilient arms 103 to move to the relaxed position.

Fig. 13 shows the needle shield fully inserted into the interior cavity 204 of the catheter hub 201. Here, the knobs have snapped into corresponding grooves of the catheter hub 201. The interaction between the groove 108 and the knob 105 securely holds the needle shield 100 in the inserted position.

According to one embodiment, the needle shield 100 may be made of a plastic material. Preferably, the plastic material has, for its intended purpose, a suitable combination of toughness, rigidity, fatigue resistance, elasticity and creep deformation resistance. Suitable plastic materials have a high creep deformation resistance, i.e. they have a low tendency to slow down or to permanently deform under the application of an external force. Thus, the catheter system 1000 of the present invention including the needle shield 100 may be stored in an assembled ready-to-use mode for an extended period of time without significant creep deformation of the arm 103 or ball protrusion 105. Advantages of the plastic needle shield 100 include: when the needle shield 100 is ejected with the needle 302 withdrawn, the tendency to release tiny plastic fragments due to scraping from the plastic catheter hub 200 is significantly reduced compared to metal. Thus, the tendency for scratches to form, which may lead to leakage through the affected connector, is greatly reduced. Furthermore, the plastic needle tip shielding device 100 may be easily color coded or transparent, depending on its particular application.

The needle shield 100 is a unitary or homogeneous injection molded needle shield 100 made of a molded plastic material. Due to the specific structure of the different parts of the needle shield 100 according to embodiments of the present invention, said needle shield 100 may be molded, e.g. injection molded, as a homogenous, i.e. monolithic block and/or as an integrated unit without interfaces between the different parts thereof. Advantages of the one-piece needle shield 100 include lower production costs compared to other devices made of multiple components that need to be assembled. In this regard, the needle shield 100 may be made of a thermoplastic polymer. The thermoplastic polymer may be transparent, amorphous, or contain alternating regions of transparency and amorphous. The gradation resistance of the selected thermoplastic polymer is preferably at least 1200MPa (ISO527, ASTM D638). Suitable plastics for use in the needle shield 300 may be selected from the group comprising Polyoxymethylene (POM), polybutylene terephthalate (PBTP), Polymethylmethacrylate (PMMA), Acrylonitrile Butadiene Styrene (ABS), Styrene Acrylonitrile (SAN), Acrylonitrile Styrene Acrylate (ASA), Polystyrene (PS), Styrene Butadiene (SB), Liquid Crystal Polymer (LCP), Polyamide (PA), Polysulfone (PSU), Polyetherimide (PEI), Polycarbonate (PC), polyphenylene oxide (PPO), and/or PPO/SB and co-and terpolymers thereof. These polymers have the following unique advantages: due to the excellent structural memory of these polymers, they provide increased storage capacity even in the tightened state, as well as a perfect fit with the catheter hub.

Contact with two smoothly shaped bodies, such as the needle shield 100 mounted in the catheter hub 200, can create a significant attractive force between these bodies, especially when the contact area is large and they are pressed together. Potential sources of this type of attraction include intermolecular attraction between the molecules of the two bodies, where van der waals interactions and surface tension of the molecules of the two bodies are important factors. The formation of covalent bonds between closely interacting surfaces may also contribute to the generation of attractive forces. Such covalent bond formation and other types of attractive forces between two surfaces may also be generated upon radiation treatment, for example, of equipment such as catheter devices to disinfect such equipment. Such attraction forces may become significant when the needle shield 100 is to be released from the catheter hub 200. Thus, the force required to release the needle shield 300 from the catheter hub 200 becomes significantly higher than expected. This effect, which may be referred to as a "suction effect", may even compromise the intended function of the tip shield if it depends on the automatic release of a component of the device, such as a spring-biased arm, from a component of the catheter hub. The needle shield 100 is kept in contact with the catheter hub 200 in the assembled state by at least one interface between the needle shield 100 and the catheter hub 200. Thus, in one embodiment, the surface of the needle shield 100 that contacts the interior lumen of the catheter hub is made of a polymeric material that is different from the polymeric material of the catheter hub.

In the claims, the term "comprising" does not exclude the presence of other elements or steps. Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Furthermore, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Furthermore, singular references do not exclude a plurality. The terms "a", "an", "first", "second", etc. do not exclude a plurality. Reference numerals in the claims are used for illustrative embodiments only and should not be construed to limit the scope of the claims in any way.

Claims (13)

1. A needle tip shielding device (100) comprising: a base plate (101) having a hole extending therethrough from a proximal side of the base plate (101) to a distal side of the base plate (101); and at least one resilient arm (103) extending at a connection point on the substrate (101); wherein

Said at least one resilient arm (103) having a rest state in which a distal hook (104) of said resilient arm (103) will coincide with a straight imaginary line extending longitudinally through said hole (102) in the axial direction of said base plate (101),

said at least one resilient arm (103) comprising a knob (105) at its distal end, said knob (105) extending transversely from the resilient arm (103);

wherein the knob (105) is formed by an outer curvature in a transversal plane (106) around an axis parallel to the central axis of the needle tip shielding device (100).

2. The needle tip shielding device (100) according to claim 1, wherein said knob (105) is formed by an outer curvature within a mid-sagittal plane (107) around an axis perpendicular to the central axis of the needle tip shielding device (100).

3. The needle tip shielding device (100) according to claim 1 or 2, wherein a radius of the outer curvature in the transverse plane (106) is an intermediate distance from the outer curvature in the transverse plane (106) to a straight imaginary line extending longitudinally through the hole (102) in an axial direction of the base plate (101), or smaller.

4. The needle tip shielding device (100) according to any of the preceding claims, wherein the intermediate radius of the outer curvature in said transverse plane (106) is 2-0.1mm, preferably 0.8-0.2mm, or less.

5. The needle tip shielding device (100) according to any one of the preceding claims, wherein the radius of the outer curvature in the mid-sagittal plane (107) is the intermediate distance from the outer curvature in the mid-sagittal plane (107) to the intersection axis perpendicular to the straight imaginary line extending longitudinally through the hole (102) in the axial direction of the base plate (101), or smaller.

6. The needle tip shielding device (100) according to any of the preceding claims, wherein the radius of the outer curvature in the mid-sagittal plane (107) is 2-0.1mm, preferably 0.8-0.2mm, or less.

7. The needle tip shielding device (100) according to any of the preceding claims, wherein the knob (105) has a shape without sharp protruding edges, such as a hemisphere or a wedge shape, a cuboid or a polyhedron with rounded corners.

8. The needle tip shielding device (100) according to claim 1, wherein said spring clip needle tip shielding device (100) has an outer diameter in a lateral plane intersecting the knob (105) which is larger than an outer diameter of the base plate in a lateral plane intersecting the base plate when the at least one arm is in the rest position.

9. The needle tip shielding device (100) according to any of claims 1 to 8, wherein the number of resilient arms is at least two, each having a knob (105) with the same proximal distance as the base plate (102).

10. The needle tip shielding device (100) according to any of claims 1 to 9, wherein the number of resilient arms is at least two, each having a knob (105) with a different proximal distance from the base plate (102).

11. The needle tip shielding device (100) according to any of the preceding claims, wherein said needle tip shielding device (100) is made of polycarbonate or a copolymer of polycarbonate and polyester.

12. The needle tip shielding device (100) according to any of the preceding claims, said needle tip shielding device (100) being injection molded.

13. A catheter instrument (1000) comprising the needle tip shielding device (100) according to any one of claims 1 to 12, a catheter assembly (200) and a needle assembly (300),

wherein the needle assembly (300) is disposed in the catheter hub (200) such that the needle (301) of the needle assembly (300) is slidingly disposed in the lumen (203) of the catheter (202) of the catheter assembly (200) such that the needle (301) can be withdrawn proximally from the catheter assembly (200);

wherein the needle tip shielding device (100) is arranged in the end cavity (207) on the needle shaft (302) such that the at least one arm (103) rests on the needle shaft (302) of the needle (301) and is spring loaded by the needle shaft (302),

in the assembled state, the needle (301) is slidingly arranged in the through hole of the substrate (102),

in the release state, when the needle hub (301) is withdrawn from the catheter hub (300), the needle bump (303) will interact with the base plate (102) to release the needle shield (100) from the catheter hub (200) while the at least one arm (103) will cover the needle tip (304) of the needle (301);

characterized in that, in the assembled state, the at least one knob (105) will interact with at least one circumferential groove (205) or ridge (206) in the catheter assembly (200) reversibly locking the needle tip shielding device (100) in the catheter assembly (200).