WO2008009984A1

WO2008009984A1 - Skin pricking device

Info

Publication number: WO2008009984A1
Application number: PCT/GB2007/050329
Authority: WO
Inventors: Clive Nicholls
Original assignee: Owen Mumford Limited
Priority date: 2006-07-18
Filing date: 2007-06-11
Publication date: 2008-01-24
Also published as: CN201303942Y; DE212007000052U1; PL118133U1; GB0614232D0; GB2440118A

Abstract

A skin pricking device (10) comprises a housing (12), a lancet (28) disposed within the housing and a lancet cap (34) covering a tip of a needle (32) of the lancet. The needle and the lancet cap are aligned along a movement path within the housing. A driver (46, 54, 62, 66) is provided, the driver being moveable in a continuous action along the path. The lancet is coupled to the driver by a spring. The driver is configured to first engage the cap to remove it from the needle and out of the movement path of the needle. The driver subsequently releases the spring to drive the lancet along the cleared movement path.

Description

Skin Pricking Device

The present invention relates to a skin pricking device and in particular, though not necessarily, to a skin pricking device for use in providing a sample of blood.

In the medical and related diagnostic and testing fields, it is often required to take small samples of blood from a subject for the purpose of testing or analysing the blood. A common way of achieving this is by using a small needle to pierce the skin at a location where blood vessels are close to the surface. The combination of a needle and its holder is commonly known as a lancet. In order to avoid infection and contamination, lancets are preferably intended for single use and are disposable. They must therefore be compact to allow users to carry multiple lancets on their person, and cheap to manufacture.

A number of disposable lancet devices are currently on the market. These include the Unistik™ manufactured and marketed by Owen Mumford Ltd (Woodstock, UK). The current designs comprise a moulded plastics casing within which is mounted a short, spring-loaded needle. A trigger is formed in the casing which, when depressed, releases the lancet causing the tip to be fired out through an opening in the casing. Some of the current designs require an operator to preload or cock the spring prior to firing. In other designs, the lancet devices are supplied already cocked. It is also generally necessary for users to remove a cap from the front of the device or the needle tip prior to firing. Users must therefore perform at least two steps, and sometimes three, in order to perform the blood sampling procedure.

There exists a desire for a lancet device which is simpler to operate than current designs. Of course, any improved design must meet high standards with regard to manufacturing costs. It must also be reliable, ensuring that lancet devices are provided to users in an operable condition. The present invention has been devised with the foregoing in mind.

According to a first aspect of the present invention there is provided a skin pricking device comprising: a housing having an opening therein; a lancet disposed within the housing; a lancet cap covering a tip of a needle of said lancet, the needle and lancet cap being aligned along a firing path within the housing, said opening also being aligned with the firing path; a driver within the housing and moveable substantially in the direction of said firing path; and a spring coupled between the driver and the lancet needle; wherein movement of the driver in said direction causes the spring to be compressed, the cap to be disengaged from the lancet needle and moved out of the firing path, and the spring to be released thereby driving the lancet along the cleared firing path to a position where the tip of the lancet needle projects out through the opening in the housing.

It is an advantage that the device is easy to use, and that it can be used with one-hand. The majority of the components of the device can be manufactured from plastics materials, providing the advantage that it is inexpensive and easy to manufacture.

Preferably, the trigger mechanism is moveable relative to the housing. More preferably, the trigger mechanism is telescopically mounted in the housing. The trigger mechanism may be actuated by pressing it into the housing.

It is preferred that the lancet cap covers said needle tip prior to actuation of the trigger mechanism. Actuation of the trigger mechanism may then cause the guide means to remove the cap from the needle and out of the movement path of the needle. It is an advantage that this operation includes automatically uncapping of the lancet needle. The needle will be sterilized before being incorporated into the device. The cap could be moulded onto the needle at manufacture and the lancet sterilized before being assembled, giving an advantage that no further sterilization of the needle or any other components of the device is required, and as such the device is ready for use.

Preferably, the lancet cap is coupled to the trigger mechanism. In an embodiment, the lancet cap is coupled to the trigger mechanism by one or more flexible members. The one or more flexible members may be elongate, with a first end thereof coupled to the trigger mechanism, and a second end thereof coupled to the lancet cap. In an embodiment, the guide means comprise complementary formations on the interior of the housing and on the trigger assembly that are brought into engagement as the trigger mechanism moves through the housing. The trigger assembly complementary formations may be provided at the second end of the one or more flexible members. The complementary formations may comprise wedges or ramps, and wedge-engaging or ramp-engaging formations respectively. Preferably, wedges are provided on or in the interior of the housing, these being engageable with wedge- engaging formations provided at the second end of the one or more flexible members. It is an advantage that the housing and the trigger mechanism can easily be manufactured from e.g. moulded plastics materials, to create the formations.

Preferably, the trigger mechanism comprises a trigger button that can be actuated by an operator. More preferably, the trigger button is exterior to the housing. Operation of the device is therefore simple, as an operator need simply press the trigger into the housing to actuate the device. Grips may be provided on the housing (moulded as part of the housing or otherwise attached) to facilitate operation of the device.

Preferably, said spring is be arranged to retract the lancet fully within the housing once the device has been fired. Preferably, the spring is a platform spring. The spring may be partially pre-loaded to ensure that the lancet is triggered with sufficient force to project from the opening and pierce the skin of a person. The partially pre-loaded spring may be compressed or extended. The platform spring may be integrally formed with the trigger assembly during manufacture thereof.

The device may be provided with lancet retaining means arranged to substantially prevent movement of the lancet through the housing until the trigger has been fully actuated. The lancet retaining means may comprise cooperating components on the interior of the housing and on the lancet.

In an embodiment, the device further comprises locking means configured to lock the trigger mechanism relative to and within the housing in a predetermined position once the device has been triggered. This helps to avoid any skin pricking accidents and the problems of infection and contamination etc. According to a second aspect of the present invention there is provided a housing having an opening therein and comprising a first set of locking formations; a lancet disposed within the housing and having a second set of locking formations for releasably engaging said first set of locking formation; a lancet cap covering a tip of a needle of the lancet, the needle and lancet cap being aligned along a firing path within the housing, said opening also being aligned with the firing path; a guide track within the housing and extending substantially in the direction of said firing path; a driver mounted in said guide track and having formations for engaging the lancet cap and formations for releasing said second set of locking formations from said first set of locking formations; a spring coupled between the lancet and the driver; and a lancet cap deflection formation disposed adjacent to the lancet cap between the lancet cap and said opening.

For a better understanding of the present invention and in order to show how the same may be carried into effect, reference will now be made by way of example to the accompanying drawings in which:

Figure 1 is a perspective view of a skin pricking device;

Figure 2 is a perspective view of the under side of an upper casing of the skin pricking device of Figure 1; Figure 3 is a perspective view of the skin pricking device of Figure 1, without the upper casing;

Figure 4 is a cross-section through the skin pricking device of Figure 1 in a horizontal plane;

Figure 5 is a cross-section through the skin pricking device of Figure 1 in a vertical plane;

Figure 6 is a perspective view of the skin pricking device of Figure 1 with a trigger of the device pressed partially into a housing;

Figure 7 is a cross-section through the skin pricking device shown in Figure 6; and Figure 8 is a partial perspective view of the device of Figure 1 after triggering of the device.

Referring to Figures 1-5, there is illustrated a skin pricking device designed for pricking a person's skin to, for example, provide a small blood sample. Typically the device is used to prick the pad of a person's finger, leaving a small spot of blood on the finger. This spot can then be collected, e.g. using a test strip, for use in performing a measurement or test. The device as shown in Figures 1-5 is in the "ready-to-use" or "starting" position, prior to actuation of the device.

A skin pricking device 10 comprises a moulded plastics housing 12. The housing 12 is constituted by an upper casing 14 and a lower casing 16. The references to "lower" and "upper" components have been chosen for convenience, and refer to the embodiment in the orientation as shown in the Figures. The underside of the upper casing 14 is provided with downwardly projecting pegs 18, which are received within receptacles 20 provided in the lower casing 16, to secure the casings 14, 16 together. The device is designed to be operated with one hand, with one end (the "needle end") held against the skin, whilst the other end (the "trigger end") is actuated by an operator to trigger the device to prick a person's skin.

The upper and lower casings 14, 16 are provided with semi-circular recesses at the needle end of the device 10 which, when the casings 14, 16 are fitted together, combine to provide a circular opening 22 out of which a needle can protrude. The upper and lower casings 14, 16 are provided with grips 24, to assist an operator in operating the device 10. A trigger 26 is located within the housing 12, at the trigger end of the device 10. The trigger 26 has a front face, or button, 27, which can be actuated by an operator by pressing it further into the housing 12.

Figures 3 and 4 show the device 10 without the upper casing 14, thus illustrating the interior workings of the device.

A lancet 28 comprises a lancet body 30 and a needle 32 mounted at and within one end thereof. The needle 32, the tip of which is directed toward the needle end of the device 10, is covered with a cap 34 to maintain sterility prior to use. The lancet body 30 has a rounded head 36, from which the needle 32 projects. The lancet cap 34 has two flexible fingers 38 which envelop the lancet body head 36, to secure it thereto prior to use.

The other end of the lancet body 30, that nearest the trigger end of the device 10, is fixed to a biasing means 40 (a platform spring is shown) via a coupling 42. In the embodiment shown, the coupling 42 comprises an enlarged tail 42a of the lancet body 30, which is secured within an enclosure 42b coupled to the end of the spring 40. The other end of the spring 40 is attached to an inner surface 44 of the trigger button 27.

Two legs 46 extend from the inner surface 44 of the trigger button 27 toward the needle end of the device 10. The trigger legs 46 terminate in outwardly turned feet 48. The trigger feet 48 are configured to have angled surfaces 49a facing inwardly towards the lancet 28. In the starting position (as shown), outer surfaces 49b of the trigger feet 48 abut inwardly turned feet 50 of the lower casing 16. The spring 40 may be slightly pre-loaded (i.e. compressed) to urge the trigger button 27 away from the housing 12, and to urge the feet 48, 50 into abutment to secure the device 10 in a state that is ready for use.

In order that the lancet 28 is not triggered before it is desirable or required to do so, the lancet body 30 is further provided with two arms 51, disposed either side of the coupling 42. The arms 51 extend towards the inner face 44 of the trigger button 27, and terminate in outwardly turned projections 51a. The projections 51a have outer surfaces 51b that are angled outwardly towards the walls of the lower casing 16. The lower casing 16 is provided with inwardly projecting stop members 52, which abut inner surfaces 51c of the projections 51a in the starting position. The stops 52 prevent premature forward movement of the lancet 28. In the embodiment shown, the lower casing receptacles 20 are provided within the stops 52.

The inner surface 44 of the trigger button 27 is also provided with flexible arms 54. The flexible arms 54 extend from the inner surface 44 of the trigger button 27 towards the needle end of the device 10. The flexible arms 54 terminate, and combine as a plate 56. The plate 56 acts as a support for mounting the lancet cap 34. In the embodiment shown, the lancet cap 34 is fixed to the support 56 by means of pegs 58, which locate within apertures 60 in the lancet cap 34. Upwardly extending ramps 62 are provided on either side of the support 56, the ramps 62 being tapered toward the needle end of the device 10.

The base of the lower casing 16 in the vicinity of the needle end of the device 10 comprises a downwardly sloped surface 64. The decline of the sloped surface 64 extends from a position proximate the location of the lancet cap 34 when the device 10 is in the starting position, towards the needle end of the device 10.

As can be seen from Figure 2, the underside of the upper casing 14 comprises downwardly projecting wedges 66. The wedges 66 taper from the needle end of the upper casing 14 towards the trigger end of the upper casing 14. The gradient of the wedges 66 (when the upper casing 14 is in place as shown e.g. in Figure 1) corresponds to that of the sloped surface of the lower casing 16. This can be seen, for example, in Figure 5.

Finally, the trigger legs 46 further comprise outwardly projecting lock-out legs 68. The lock-out legs 68, which are located on the trigger legs 46 in the vicinity of the trigger button 27, diverge from the trigger legs 46 towards the trigger button 27.

The device shown in Figures 1-5, and as described above, is in the "ready-to-use" configuration. Operation of the device 10 will now be described with reference to Figures 6-8.

As an operator initiates actuation by pressing the trigger button 27, the trigger 26 is urged into the housing 12, and the spring 40 is compressed, as shown in Figure 6. Movement of the trigger 26 into the housing 12 includes movement of the flexible legs 54 further into the housing 12, which uncaps the lancet cap 34 from the lancet body head 36, to expose the needle 32. After the lancet 28 has been uncapped, and as the trigger 26 continues to be urged into the housing 12, the wedges 66 of the upper casing 14 engage the ramps 62 of the support plate 56. The trigger legs 54 flex and the movement path of the lancet support plate 56 is along and down the sloped surface 64 of the base of the lower casing 16. It will be appreciated that, in this operational state, the needle 32 is aligned with the aperture 22, and the lancet cap 34 has been moved out of the movement path of the needle 32. Continued pressing of the trigger 26 compresses the spring 40 to store energy therein. The lancet 28 is prevented from firing by the abutment of the lancet arm projections 51a and the lower casing stop members 52. The device 10 is now "armed" and ready for firing. It will also be appreciated that the engagement between the ramps 62 and the wedges 66 enables the device 10 to be held upside down in use.

Further continued pressing of the trigger button 27 brings the angled surfaces 49a of the trigger feet 48 into contact with the angled surfaces 51b of the lancet arm projections 51a. This contact urges the lancet arms 51 inwards towards each other, until the lancet arm projections 51a are freed from the lower casing stop members 52. At this point, the spring 40 rapidly expands, releasing the energy hitherto fore stored therein. This urges the lancet 28 forwards, through the housing 12, causing the needle 32 to project out of the aperture 22 to prick a person's skin. The head 36 of the lancet body 30 is brought into contact with the inner surface of the housing 12 surrounding the aperture 22, and this, and the thickness of the housing 12 surrounding the aperture 22 can be chosen to limit the distance that the needle 32 can protrude from the opening 22, thereby preventing the needle 22 from penetrating the skin too deeply.

At this point, the spring 40 is overextended, so the spring 40 retracts to pull the needle 32 back through the aperture 22, and back into the housing 12, as shown in Figure 8. The needle 32 is thereby secured within the housing 12 of the device 10 after use, to prevent any skin pricking accidents being caused by the needle 32. Figure 8 also shows that, after use, the trigger 26 is secured within the housing 12 because the trigger legs 46 are held captive within the lower casing 16 of the housing 12. That is to say, the trigger feet 48 abut the lower casing stop members 52, and the lock-out legs 68 abut the lower casing feet 50. Therefore, once the skin pricking device 10 has been used, it cannot be rearmed without completely disassembling the device 10. Unless the upper casing 14 is removed from the lower casing 16 to expose the interior components of the device 10, it will not be possible to move the trigger 26 relative the housing 12 at all. The device 10 may be provided with an indicator (not shown) that clearly indicates to an operator that the device 10 has been fired and should be disposed of. It is to be noted that the trigger 26 is locked down once fired.

As the needle 32 is sterile when it is embedded within the lancet cap 34, and does not contact any other part of the device 10 before it pricks the skin, there is no need to sterilize or seal the housing 12 or the parts contained within the housing 12, other than the needle 32 and the surrounding cap 34.

In order to ensure that the spring 40 fires the lancet 28 with sufficient force to project from the aperture 22 and pierce the skin of a person, the spring 40 may be partially pre-loaded prior to assembly of the device 10.

It will be appreciated by those skilled in the art that various modifications may be made to the above described embodiment without departing from the scope of the present invention.

Claims

CLAIMS:

1. A skin pricking device comprising: a housing having an opening therein; a lancet disposed within the housing; a lancet cap covering a tip of a needle of said lancet, the needle and lancet cap being aligned along a firing path within the housing, said opening also being aligned with the firing path; a driver within the housing and moveable substantially in the direction of said firing path; and a spring coupled between the driver and the lancet needle; wherein movement of the driver in said direction causes the spring to be compressed, the cap to be disengaged from the lancet needle and moved out of the firing path, and the spring to be released thereby driving the lancet along the cleared firing path to a position where the tip of the lancet needle projects out through the opening in the housing.

2. The device of claim 1, further comprising a trigger mechanism moveable relative to the housing, whereby actuation of the trigger mechanism causes the driver to move through the housing.

3. The device of claim 2, wherein the trigger mechanism is telescopically mounted in the housing.

4. The device of claim 3, wherein the trigger mechanism is actuated by pressing it into the housing.

5. The device of any preceding claim, wherein the driver comprises a coupling between the lancet cap and the trigger mechanism.

6. The device of claim 5, wherein the lancet cap is coupled to the trigger mechanism by one or more flexible members.

7. The device of claim 6, wherein the one or more flexible members are elongate, with a first end thereof coupled to the trigger mechanism, and a second end thereof coupled to the lancet cap.

8. The device of any preceding claim, wherein complementary formations are provided on the interior of the housing and on the driver, the formations being engageable with each other as the driver moves through the housing.

9. The device of claim 8, wherein the driver complementary formations are provided at the second end of the one or more flexible members.

10. The device of claim 8 or claim 9, wherein the complementary formations comprise wedges or ramps, and wedge-engaging or ramp-engaging formations respectively.

11. The device of claim 10, wherein wedges are provided on or in the interior of the housing, these being engageable with wedge-engaging formations provided at the second end of the one or more flexible members.

12. The device of any preceding claim, wherein the trigger mechanism comprises a trigger button that can be actuated by an operator.

13. The device of claim 12, wherein the trigger button is exterior to the housing.

14. The device of any one of the preceding claims, wherein said spring is arranged to retract the lancet fully within the housing once the device has been fired.

15. The device of any one of the preceding claims, wherein said spring is a platform spring.

16. The device of any preceding claim, further comprising lancet retaining means arranged to substantially prevent movement of the lancet through the housing until the trigger has been fully actuated.

17. The device of claim 16, wherein the lancet retaining means comprises cooperating components on the interior of the housing and on the lancet.

18. The device of any preceding claim, further comprising locking means configured to lock the trigger mechanism relative to and within the housing in a predetermined position once the device has been triggered.

19. A skin pricking device comprising: a housing having an opening therein and comprising a first set of locking formations; a lancet disposed within the housing and having a second set of locking formations for releasably engaging said first set of locking formation; a lancet cap covering a tip of a needle of the lancet, the needle and lancet cap being aligned along a firing path within the housing, said opening also being aligned with the firing path; a guide track within the housing and extending substantially in the direction of said firing path; a driver mounted in said guide track and having formations for engaging the lancet cap and formations for releasing said second set of locking formations from said first set of locking formations; a spring coupled between the lancet and the driver; and a lancet cap deflection formation disposed adjacent to the lancet cap between the lancet cap and said opening.