Field of invention
The present invention relates to a needle tip guard for a medical device. In particular present invention relates to a needle tip guard for an intravenous catheter device.
Back ground of the invention
Accidental needle sticks/pricks have become a major concern to health-care worker. According to a study, the conversion rate for HIV positive needle sticks is 1 in 250 sticks. It is well known and understood by healthcare workers that sharp surgical instruments, such as catheter needles, have a significant potential for harm to healthcare workers. The rapid handling of these sharp instruments can lead to accidental cuts or puncture wounds during surgery.
Thus, there is an inherent incentive for improvement of existing safety from needle stick technology that can reduce and more ideally eradicate needle sticks for the health care workers. The chances of the healthcare worker contracting some fatal infection or disease because of accidental needle stick comes with a heavily price on the society and their healthcare
Typically, maximum needle sticks or stabs occur in specific situations, such as a surgery. Another occasion is at the time of passing a used catheter to a scrub nurse. Another is when a surgeon swabs a bleeder and accidentally sticks/pricks stabs himself/herself (when s/he forgets that the catheter needle is in his other hand). Trauma cases are another high risk situation in which an accidental laceration can occur because there many people simultaneously working on these cases and people are rushing to perform their tasks. Yet another case of accidental needle sticks is that the needle tip safety device is lost or misplaced, the needle tip becomes dangerous for practically anyone and everyone in the proximity of the exposed needle tip.

Another instance is during the disposal of medical waste, needle sticks may occur because of accidental removal of the needle safety device. During the course of a surgery, the healthcare worker will usually remove the shield and give the exposed catheter with needle sticking out to the doctor. Similarly after completion of the use of the catheter needle, the surgeon may hand the catheter needle with exposed catheter tip to the healthcare worker for covering. This process results in loss of time and may cause accidental stabbing of the healthcare worker or the surgeon. During waste disposal, the disposer is not usually careful in handling the waste and may handle the waste roughly, which may result in removal of the shield (if already not attached) and cause sticking. This could also lead to spread of infection in the general public. Thus, there is a need to protect the healthcare workers from accidental needle sticks.
Thus, there is a need for having a needle tip guard to prevent accidental pricks and sticks. There are needle tip guards generally known and operative as a guard for the tip of a needle of the medical device. These needle tip guards are both automatic and non-automatic. Automatic needle tip guards are those guards that automatically cover the needle tip during withdrawal of the needle from a patient. Non-automatic needle tip guards are those where the healthcare worker has to manually and in as a separate operation require covering the needle tip. The non-automatic needle guards have their obvious flaws such as manual operation of fixing the needle guard, the needle guard existing as a separate piece, difficulty in pushing the guard over the needle tip, loss of time, obvious danger of accidental prick etc. The automatic needle tip guards were the improvement over manually operated needle tip guards
It is, therefore, one of the objects of this invention to provide a needle tip guard which provides a better protection against accidental needle tip sticks and reducing the complexity of manufacture of prior known needle tip guards
Summary of the invention
A needle tip guard for a medical device, the needle tip guard (28) comprising a base having a bore extending in an axial direction through the base for receiving a needle; and two opposing jaws extending from the base generally in the axial direction and

each having a head portion in the region of its free end, wherein at least one of the head portions forms a locking shoulder for securing the needle tip guard in a housing of the medical device, wherein an elastic component surrounds the jaws in a region between the base portion and the head portions; wherein the elastic component and the jaws are configured such that the jaws can be spread apart against a restoring force of the elastic component in order to allow the needle received in the bore to extend all the way through the needle tip guard and wherein due to the arrangement of the elastic component between the base portion and the head portions of the jaws, a locking recess for receiving a locking protrusion formed inside the housing of the medical device is formed between the elastic component and the locking shoulder of the at least one head portion. When the locking protrusion engages with the recess formed by the shoulder of the at least one head portion and the elastic component, the needle safety device is safely secured inside the housing of the medical device and is prevented from movement in the axial direction relative to the housing.
An object and advantage of the present invention is that the medical device such as catheter assembly are stored and shelved prior to use with the jaws spread apart over the needle. Due to the elastic component exerting its restoring force on the jaws in the spread apart state of the jaws, the elastic component ensures that the spread apart jaws will snap together and guard the needle tip upon withdrawal of the needle from the medical device even after a longer shelf time, thereby continuously ensuring a correct functioning of the needle safety device.
Another object and advantage of this invention is that the elastic component prevents the jaws from becoming loose when the needle tip guard slides along the needle, thereby further aiding a correct functioning of the needle tip guard.
Another advantage and object of the invention is that the elastic component being arranged in a region between the base portion and the head portions of the jaws, the elastic component also helps prevent the needle tip from protruding sideways out of the needle tip guard, thereby further increasing the protecting function of the needle tip guard.

Description of accompanying drawings
FIGURE1 shows a view partly in cross-section of a wing housing of an intravenous catheter apparatus, including a needle safety device of the invention inserted therein and a needle extending through it;
FIGURE2 shows a view partly in cross-section of the wing housing of FIGURE1, including the needle safety device, but not the needle;
FIGURE3A shows a side view of the needle safety device of FIGURE1 including a tension ring, with the needle safety device guarding the tip of the needle;
FIGURE3B shows a side view of the needle safety device of FIGURE3A without the needle or the tension ring;
FIGURE3C shows a depression for receiving a tension ring, which is formed in the outer surface of a needle safety device according to an alternative embodiment of the invention;
FIGURE4A shows a side view of an alternative embodiment of the needle safety device of the invention, including a tension ring;
FIGURE4B shows a side view of the needle safety device of FIGURE4A without the tension ring;
FIGURE5 shows a plan view of the wing housing of FIGURE1;
FIGURE6A shows a cross-sectional view of a section of the wing housing of FIGURE5 detailing an annular locking protrusion;
FIGURE6B shows a cross-sectional view of a section of the wing housing of FIGURE5 detailing an alternative embodiment of the annular locking protrusion;

FIGURE7A shows a side view of the needle tip region of the needle of FIGURE1 showing the details of an enlargement formed on the outer surface of the needle;
FIGURE7B shows a plan view of the needle tip region of FIGURE7A;
FIGURE8 shows a cross-sectional view of the needle of FIGURE7 in the region of the enlargement which has been formed by welding; and
FIGURE9 shows cross-sectional views of the needle of FIGURE7 in the region of the enlargement, illustrating the formation of the enlargement by a deposition process.
Detailed description of the invention and drawings
For ease in understanding the invention, as an illustration, a medical device, in particular an intravenous catheter apparatus, comprising a needle of the type mentioned herein below and a needle tip guard, in particular of the below described kind, which is slidably arranged on the needle for protecting the needle tip, wherein the needle safety device includes a base portion having a bore extending thorugh it for receiving the needle, the bore being adapted to the principal outer profile of the needle.
Referring to FIGURE 1, a catheter hub or wing housing 10 of an intravenous catheter apparatus is shown. The wing housing 10 comprises a main body 12 of generally tubular form and extending in an axial direction. The main body has a distal end 14 and a proximal end 16. A catheter 17 (FIGURE 5) is attached to the main body 12 at the distal end 14 of the main body 12. A port 18 extends from the main body 12 in a direction generally perpendicular to the axial direction. Wings 20 (FIGURE 5) are provided at the main body 12 opposite from the port 18. The main body 12 defines a chamber 22 extending from the proximal end 16 towards the distal end 14.
Prior to use of the intravenous catheter apparatus, a needle 24 extends through the wing housing 10 in the axial direction. The needle 24 has an inner profile, i.e. cross-section area defined by the inner periphery or circumference of the needle 24, which is substantially constant across the length of the needle 24. A principal outer profile,

i.e. principal cross- section area defined by the outer periphery or circumference of the needle 24, is also substantially constant across the length of the needle 24 except for an enlargement 26 of the needle 24 provided in the region of the needle tip at the distal end of the needle 24, which will be described in more detail below with reference to FIGURES 7 to 9.
Still referring to FIGURE 1, a needle safety device 28 is slideably arranged on the needle 24. Prior to use of the intravenous catheter apparatus, the needle safety device 28 is inserted into the chamber 22 from the proximal end 16 of the main body 12.
As can be seen from FIGURES 1, 3 and 4, the needle safety device 28 comprises a base portion 30 which has a bore extending in the axial direction therethrough for receiving the needle 24. The bore is matched in shape and size to the principal outer profile of the needle 24.'
First and second jaws 34, 36 extend from the base portion 30 generally in the axial direction. The first jaw 34 has a first head portion 38 in the region of its free end, and the second jaw 36 has a second head portion 40 in the region of its free end. The first head portion 38 extends beyond the second head portion 40 and has an angled end section 42 at its free end, which extends towards the second jaw 36 in a direction generally perpendicular to the axial direction.
The length of the angled end section 42 is selected such that the angled end section 42 protrudes over at least a part of the second head portion 40, when the jaws 34, 36 are in a relaxed position as is shown in FIGURES 2, 3 and 4. When the needle 24 extends all the way through the needle safety device 28, such as prior to use of the intravenous catheter device as shown in FIGURE 1, the angled end section 42 is supported on the needle 24, whereby the first jaw 34 is forced away from the second jaw 36 from its relaxed position into a spread apart position.
The jaws 34, 36 are surrounded by a tension ring 44 in a region between the base portion 30 and the head portions 38, 40. The tension ring 44 is made from an elastic material, such as rubber, silicone or the like. The tension ring 44 is fitted around the

jaws 34, 36 such that it exerts a restoring force on the jaws 34, 36, when the jaws are spread apart by the needle 24, as shown in FIGURE 1. This is merely a preferred embodiment and the tension ring is an elastic component that may comprise a tension ring completely surrounding the jaws, and/or a clamp, bracket, "C" clip or the like surrounding the jaws only in part.
Preferably, the above described tension ring or the elastic component is made from a material having elastic properties, for example, an elastic material such as rubber, silicone or the like. Due to its elastic properties, the elastic component creates a restoring force on the jaws, when the needle fully extends through the needle safety device thereby spreading the jaws apart and expanding the elastic component. As soon as the needle tip passes the free ends of the jaws upon pulling the needle through the needle safety device, the jaws are positively collapsed by the elastic component due to its restoring force.
As is illustrated in FIGURES 1, 2, 3A and 4A, the tension ring 44 covers a substantial part of the jaws 34, 36 seen in the axial direction. According to a preferred embodiment the elastic component covers a substantial part of the jaws. The elastic component forms a partial sidewall and together with the jaws defines a chamber inside the needle safety device, in which the needle tip is held after complete withdrawal of the needle from the medical device, thereby further increasing the guarding function of the needle safety device. More particularly, the axial dimension of the tension ring may range from about one fifth of the length of the jaws to about two thirds or three fourth of the length of the jaws, and preferably is in the range of about one third of the length of the jaws.
Referring to FIGURES 3B and 4B, the jaws 34, 36 are connected to each other by a link 46. The link 46 is arranged approximately half way along the length of the jaws 34, 36 between the base portion 30 and the head portions 38, 40, i.e. in the region of the tension ring 44. More specifically, the link 46 is covered by the tension ring 44, as is illustrated in FIGURES 3A and 4A. In accordance with a further embodiment, the jaws are connected to each other by at least one link in a region between the base portion and the head portions. Preferably, the link is arranged in the region of the

elastic component. The link may be provided on only one side of the jaws. Alternatively, first and second links may be provided on opposite sides of the jaws.
Preferably, the at least one link is formed to have spring-like properties such that the jaws can be spread apart against a restoring force of the link. For example, the link may have a curved shape, such as an S- or Z- like shape. Alternatively, the link may have a substantially straight shape.
In the embodiments shown, the link 46 is provided on only one side of the jaws 34, 36. However, it is generally possible to provide a link on both sides of the jaws 34, 36. Furthermore, it is generally possible to provide more than one link on one side of the jaws 34, 36 or on both sides of the jaws 34, 36.
The link 46 shown in FIGURES 3B and 4B has a curved shape and, in particular, an S-like shape providing the link 46 with spring-like properties. Thereby the link 46 also exerts a restoring force on the jaws 34, 36, when the jaws 34, 36 are spread apart by the needle 24, as shown in FIGURE 1. The link 46 thus aids the tension ring 44 in biasing the jaws 34, 36 towards each other.
It is to be appreciated that the link 46 does not necessarily need to have an S-like shape, but it may also have a Z-like shape or any other shape which is suitable to provide the link 46 with spring-like properties. It is within the scope of this invention for the link 46 to have straight or substantially straight shape.
It can be seen from the preferred embodiment that at least one link 46 prevents the two jaws 34, 36 from spreading apart two far, thus preventing over- stretching of the elastic component 44 which could result in a loss of elastic properties. Furthermore, the link 46 supports the elastic component 44 in exerting a force on the jaws 34, 36 in the collapsing direction, thereby aiding the elastic component 44 in preventing the jaws 34, 36 from becoming loose when the needle tip guard 28 slides along the needle 24. Further, the link 46 causes the jaws 34, 36 to collapse even if the elastic component 44 should fail in its function. As already stated, the link 46 is designed such that it retains its spring-like properties over the period of shelf live.

The base portion 30, the jaws 34, 36 and the link 46 are integrally formed from a plastic material, for example, by injection moulding. For the purpose of a simplified and cost-effective production of the needle tip guard 28, the base portion 30, the jaws 34, 36, and preferably also the at least one link may be integrally formed and preferably made from a plastic material such as by injection molding. Alternatively, the base portion 30, the jaws 34, 36 and preferably at least one of the link 46 may be made from a metal material.
According to a further embodiment, the base portion 30, the jaws 34, 36 and/or the link 46 each comprise a different material or combination of materials, such as a different plastic material, a different metal material or a different combination of plastic and /or metal materials. For example, the base 30 may be made from a metal material and the jaws 34, 36 may be made from a plastic material, or vice versa. It is also considered that the inner part of the jaws 34, 36, which contacts the needle 28, is made from a thermoplastic material such as TPE, whereas the outer part of the jaws 34, 36 may be made from a different material, for example, a plastic, metal, composite or elastomer material, so that the needle tip guard 28 causes less friction when sliding along the needle 24 thereby facilitating the withdrawal of the needle 24.
In order to prevent the needle tip 56 protected by the needle tip guard 28 from protruding beyond the free ends of the jaws 34, 36, at least one of the jaws 34, 36 has an angled end section at its free end, which extends towards the other one of the jaws 34, 36 in a direction generally perpendicular to the axial direction. This can be seen from FIGURES 3B and 4B where the jaws 34, 36 are slightly angled towards each other in the region of the tension ring 44, resulting in the outer profile of the needle safety device 28 being tapered towards the head portions 38, 40.
The length, preferably, of at least one angled end section is selected such that the angled end section is supported on the needle 28 when the needle 28 extends all the way through the needle tip guard 24, thereby spreading the jaws 34, 36 apart far enough for the shoulder 50 of the head portion 38, 40 of the jaw 34, 36 having the angled end section to be able to engage behind the locking protrusion 54 provided in the housing 10 of the medical device.

In order to hold the tension ring 44 in a fixed position on the jaws 34, 36, two part annular protrusions 48 are formed on the outer surface of the jaws 34, 36, as shown in FIGURES 1, 2 and 3. The part annular protrusions 48 are spaced apart a distance matched to the axial dimension of the tension ring 44. The part annular protrusions 48 can thus receive the tension ring 44 between themselves, thereby functioning as guides for the tension ring 44 and securing the position of the tension ring 44 on the jaws 34, 36. In addition to or instead of the part annular protrusions 48, a depression or groove 49 may be formed in the outer surface of the jaws 34, 36, as shown in FIGURE 3C.
It is to be noted that the part annular protrusions 48 and depression or groove 49 are optional, i.e. the needle safety device 28 can also be made without any part annular protrusions, depression or groove, as shown in FIGURES 4A and 4B.
As can be seen from FIGURES 3 and 4, a locking shoulder 50 is formed at the side of each head portion 38, 40 facing the tension ring 44. The locking shoulder 50 and the tension ring 44 together form a recess or groove 52.
Referring again to FIGURE 1 , an annular locking protrusion 54 is formed on the inner surface of the main body 12 of the wing housing 10 and protrudes into the chamber 22.
Prior to use of the intravenous catheter apparatus, i.e. when the needle safety device 28 is inserted into the chamber 22 and the needle 24 extends all the way through the needle safety device 28 and the wing housing 10, the annular locking protrusion 54 is received in the recess 52 defined by the tension ring 44 and the head portion 38 of the first jaw 34, which is forced away from the second jaw 36 due to the angled end section 42 supported on the needle 24.
Because of the annular locking protrusion 54 engaging into the recess 52 of the needle safety device 28 in the spread apart state of the jaws 34, 36, the needle safety device 28 is secured against movement relative to the main body 12 in the axial direction. Specifically, the needle safety device 28 cannot be pulled out of the

wing housing 10, since the locking shoulder 50 of the head portion 38 of the first jaw 34 engages behind the annular locking protrusion 54.
As is illustrated in FIGURE 5, the annular locking protrusion 54 is a distance away from the proximal end 16 of the main body 12, this distance being in the range of 5 mm to 6 mm or more.
The annular locking protrusion 54 may have a substantially rectangular profile with rounded edges (FIGURE 6A), a rounded profile similar to a Gaussian curve or a semi- sinusoidal curve (FIGURE 6B), or any other profile suitable for locking of the needle safety device 28 in the wing housing 10.
Preferably, the locking protrusion 54 is of continuous annular shape. However, it is generally also possible to consider an annular locking protrusion 54 having one or more interruptions.
When the needle 24 is being withdrawn from a patient and, thus, from the intravenous catheter apparatus, the needle 24 is simultaneously pulled through the needle safety device 28. As has been mentioned above, as long as the jaws 34, 36 are in their spread apart position, the needle safety device 28 is secured against axial movement relative to the main body 12, i.e. the needle safety device 28 remains in the wing housing 10.
However, as soon as the tip 56 of the needle 24 moves into the needle safety device 28, i.e. passes beyond the angled end section 42 of the first jaw 34, the first jaw 34 snaps back or collapses into its relaxed position, as shown in FIGURE 3, due to the restoring force exerted by the tension ring 44 and the link 46,
When the first jaw 34 adopts its relaxed position, the locking protrusion 54 is released from the recess 52 and the locking shoulder 50 of the first head portion 38 is disengaged from the locking protrusion 54. As a result, the safety device 28 is free to move relative to the main body 12 in the axial direction. Specifically, the needle safety device 28 can now be pulled out of the wing housing 10, as is indicated in FIGURE 2.

As is illustrated in FIGURE S 3A and 7, the position of the enlargement 26 formed on the outer surface of the needle 24 is selected such that the enlargement 26 abuts the base portion 30 of the needle safety device 28 as soon as the needle tip 56 has passed the free end of the second jaw 36.
The needle 24 for a medical device such as an intravenous catheter apparatus, that has an inner profile, i.e. cross-section area defined by the inner periphery or circumference of the needle 24, a principal outer profile, i.e. principal cross- section area defined by the outer periphery or circumference of the needle 24, and a needle tip 56, the needle 24 further comprising at least one enlargement 26 in the region of the needle tip 56, wherein the enlargement 26 is formed from an increase of the outer profile, whereas the inner profile remains substantially unchanged. It is understood that the enlargement 26 can also be grove near the needle tip 56 i.e. the formation of groove is by way of decrease in the inner profile and the outer profile remains the same.
Since the maximum outer dimension of the needle 24 in the region of the enlargement 26 is larger than the dimension of the bore in the base portion 30, which is adapted to the principal outer profile or circumference of the needle 24, the needle 24 can not be further pulled out of the needle safety device 28 than is shown in FIGURE 3. In other words, because of the enlargement 26, the needle safety device 28 cannot slide off the needle 24 during normal use of the needle 24 and needle safety device 28, i.e. unless an excessive external force is applied to the needle 24 and/ or the needle safety device 28.
With the needle tip 56 captured inside the needle safety device 28, the needle tip 56 is covered by the angled end section 42 of the first jaw 34. At the same time, the tension ring 44 prevents the needle tip 56 from coming sideways out of the needle safety device 28. Hence, the needle tip 56 is safely guarded by the needle safety device 28.
Referring to FIGURES 8 and 9, the enlargement 26 of the needle 24 is formed such that the inner profile of the needle 24 is not affected by the formation of the

enlargement 26, i.e. remains substantially unchanged. Thereby, when the needle 24 penetrates a vein, the flow of blood through the needle 24 will not be adversely affected by the enlargement 26.
The enlargement 26 may be formed as a bump by subjecting the needle 24 to concentrated heat at a localized area, for example, using a welding process, such as a build-up welding process or a laser welding process, with or without addition of additional material (FIGURE 8).
Alternatively, the enlargement 26 may be formed by dispensing additional material 58 onto the outer surface of the needle 24, such as an adhesive, a resin or a metal material. The additional material 58 may be placed in a recess 60 which has been formed in the outer surface of the needle 24 prior to dispensing the additional material 58. However, formation of the recess 60 is optional. In the case of the additional material being a metal material, the enlargement 26 may, for example, be formed by build-up welding of the additional material onto the needle.
Although only one enlargement 26 is shown in FIGURES 7 to 9, it is to be noted that more than one enlargement may be present on the outer surface of the needle 24.
Thus, there is shown and described a unique design and concept of a needle tip guard. While this description is directed to a particular embodiment, it is understood that those skilled in the art may conceive modifications and/or variations to the specific embodiments shown and described herein. Any such modifications or variations which fall within the purview of this description are intended to be included therein as well. It is understood that the description herein is intended to be illustrative only and is not intended to be limitative. Rather, the scope of the invention described herein is limited only by the claims appended hereto.

WE CLAIM:
1. A needle tip guard (28) for a medical device comprising
- a housing 10, the needle tip guard (28) having a base portion (30) having a
bore extending in an axial direction through the bore for receiving a needle
(24); and two opposing jaws (34, 36) extending from the base portion (30)
generally in the axial direction and each having a head portion (38, 40) in the
region of its free end;
wherein at least one of the head portions (38, 40) forms a locking shoulder (50) for securing the needle safety device (28) in the housing (10) of the medical device, wherein an elastic component (44) surrounding the jaws (34, 36) in a region between the base portion (30) and the head portions (38, 40);
- wherein the elastic component (44) and the jaws (34, 36) are configured such that the jaws (34, 36) can be spread apart against a restoring force of the elastic component (44) in order to allow the needle (24) received in the bore to extend all the way through the needle safety device (28);
- wherein the elastic component (44) between the base portion (30) and the head portions ( 38, 40) of the jaws (34, 36), a locking recess (52) for receiving a locking protrusion (54) formed inside the housing (10) of the medical device is formed between the elastic component (44) and the locking shoulder (50) of the at least one head portion (38, 40); and
- wherein the locking protrusion (54) engages with the recess (52) formed by the shoulder of the at least one head portion (38, 40) and the elastic component (44), the needle tip guard is safely secured inside the housing (10) of the medical device and is prevented from movement in the axial direction relative to the housing (10).

2. A needle tip guard (28) as claimed in claim 1 wherein the axial direction the elastic component (44) covers a substantial part of the jaws (34, 36).
3. A needle tip guard (28) as claimed in claims 1 or 2 wherein an axial dimension of the elastic component (44) ranges from about one fifth of the length of the jaws (34,

36) to about two thirds or three quarters of the length of the jaws (34, 36), and preferably is in the range of about one third of the length of the jaws (34, 36).
4. A needle tip guard (28) as claimed in claim 1 wherein the elastic component (44) is made from a material having elastic properties or an elastic material.
5. A needle tip guard (28) as claimed in claim 1 wherein the elastic component comprises a tension ring (44) completely surrounding the jaws (34, 36), and/or a clamp or bracket partly surrounding the jaws (34, 36).
6. A needle tip guard (28) as claimed in claim 1 wherein the jaws (34, 36) are connected to each other by at least one link (46) in a region between the base portion (30) and the head portions (38, 40).
7. A needle tip guard (28) as claimed in claim 6 wherein the link (46) is arranged in the region of the elastic component (44).
8. A needle tip guard (28) as claimed in claims 6 and 7 wherein the link (46) is provided on only one side of the jaws (34, 36).
9. A needle tip guard (28) as claimed in claims 6 and 7 wherein the first and second links are provided on opposite sides of the jaws (34, 36).

10. A needle tip guard (28) as claimed in claims 6 an d7 wherein each link (46) is formed to have spring-like properties such that the jaws (34, 36) can be spread apart against a restoring force of the link (46).
11. A needle tip guard (28) as claimed in claims 6 to 10 wherein each link (46) has a curved shape such as an S- or Z-like shape, or a substantially straight shape.
12. A needle tip guard (28) as claimed in claim 1 wherein the base portion (30), the jaws (34, 36), and preferably also a link (46) connecting the jaws (34, 36), are integrally formed.

13. A needle tip guard (28) as claimed in claims 1 to 11 wherein the base portion, the jaws and/or a link (46) connecting the jaws (34, 36) each comprise a different material or combination of materials.
14. A needle tip guard (28) as claimed in claim 1 wherein at least one of the jaws (34) has an angled end section (42) at its free end, which extends towards the other one of the jaws (36) in a direction generally perpendicular to the axial direction.
15. A needle tip guard (28) as claimed in claim 14 wherein the length of the angled end section (42) is selected such that the angled end section (42) is supported on the needle (24) when the needle (24) extends all the way through the needle tip guard(28), thereby spreading the jaws (34, 36) apart far enough for the shoulder (50) of the head portion (38) of the jaw (34) having the angled end section (42) to engage with the housing (10) of the medical device for securing the needle tip guard(28) in the housing (10).
16. A needle tip guard (28) as claimed in claim 1 wherein the needle (24) has an inner profile, a principal outer profile and a needle tip (56), the needle (24) containing an enlargement (26) in the region of the needle tip (56), the enlargement (26) is formed from an increase of the outer profile of the needle (24) in at least one direction, whereas the inner profile remains substantially unchanged.
17. A needle tip guard (28) as claimed in claims 1 and 16 herein the enlargement (26) is formed by subjecting the needle (24) to concentrated heat at a localized area using for example, a welding process such as a laser welding process, with or without addition of additional material.

18. A needle tip guard (28) as claimed in claims 1, 16 and 17wherein the enlargement (26) is formed from additional material (58) dispensed onto the outer surface of the needle (24).
19. A needle tip guard (28) as claimed in claim 18 wherein the additional material (58) is selected from at least one of a plastic material, an adhesive, a resin and a metal material.

20. An intravenous catheter apparatus comprising a needle (24) in accordance with any one of claims 16 to 19; and a needle tip guard(28), in particular in accordance with any one of claims 1 to 14, slidably arranged on the needle (24) for protecting the needle tip (56), wherein the needle tip guard(28) includes a base portion (30) having a bore extending through for receiving the needle (24), the bore being adapted to the principal outer profile of the needle (24).
21. An intravenous catheter apparatus as claimed in claim 20, wherein preferably annular, locking protrusion (54) for engaging with the needle tip guard(28) is formed on an inner surface of a catheter hub (10) of the intravenous catheter apparatus.
22. An intravenous catheter apparatus as claimed in claim 21 wherein the locking protrusion (54) has a substantially rectangular profile with rounded edges or a rounded profile similar to a Gaussian curve or a semi- sinusoidal curve.