Blood letting device

Abstract: A blood letting device comprising a body (2), a base, an aperture (5) in the base, a sharp (26) with a pointed end (27), having a rest position and a cocked position, biasing means (22) adapted to rapidly urge said sharp from said cocked position to said rest position, locking means (21,30) adapted to hold said sharp in said cocked position, wherein the arrangement is such that release of said locking means (21,30) causes the sharp (26) in moving to said rest position, to prick skin which has been held in the region of said aperture (5).

Description: This invention relates to a blood letting device. There is a need to take blood samples and this is commonly done by pricking a finger with a sharp point but this may involve substantial pain and/or apprehension in a subject whose blood is to be let such that self-administration or administration may be unpleasant. Further, there is a considerable problem associated with the disposal of the sharp point. Various devices are known for letting blood but the Applicant considers all of them to have various disadvantages. One such device is disclosed in US 4,983,178 in the name of William J.Schnell. This constitutes the closest prior art. The device has a pair of arms having free ends and a lance blade carried on the upper arm. The upper arm further comprises a trigger member at its tip, which interacts with a trigger projection on the lower arm such that the upper arm can be held in a cocked position by the engagement of the trigger member on the trigger projection. A sleeve provided in an aperture in the lower arm can be pivotally moved by applying upwards pressure thereto, causing the trigger projection to move and allowing the lancing blade mounted on the upper arm to be "fired" towards the lower arm. The present invention provides:- a blood letting device comprising a base, an aperture in the base, a sleeve fitting within the aperture, arranged to turn from an original position about a hinge when the device is used, a sharp with a pointed end, having a rest position and a cocked position, biasing means adapted to rapidly urge said sharp from said cocked position to said rest position, and locking means adapted to hold said sharp in said cocked position, wherein the arrangement is such that release of said locking means causes the sharp in moving to said rest position, to prick skin which has been held in the region of said aperture, characterised in that a first latch element is provided on the base and a second latch element is provided on the sleeve, the latch elements being shaped such that when the sleeve is pushed upward, the second latch element will sit atop the first latch element so as to prevent the sleeve from returning to its original position. In a preferred aspect of the invention, the sleeve extends below the base. Where the device is intended for use in pricking fingers, it is preferred that the internal diameter of the sleeve fully within the range 0.35 to 0.70 cm, more preferably 0.50 to 0.60 cm. Preferably the lower end of the sleeve has a recess therein which will cause the skin to bulge up within the sleeve as the skin is pressed towards the sleeve so as to bring the skin into proximity with the sharp. Thus the tamper indicating means may comprise one or more frangible bridges extending between the sleeve and base, said bridge or bridges breaking when the sleeve is turned about the hinge during use. The biasing means may comprise a resilient arm extending from the base. The sharp may be provided with a removable cover which protects the user from accidental sticking during handling and maintains a piercing point forming part of the sharp in sterile condition. The sharp may comprise a pointed metal needle moulded in place in plastics using an injection moulder and at the same time the cover is moulded in place as well, whereby the needle is substantially enclosed in plastic. According to a method of the present application, the sharp of the blood letting device is sterilised due to the heat of the injection moulding process. An abutment may be provided in the plastic moulded around the needle to engage with a corresponding abutment mounted on the base to act as the locking means. Thus the locking means may be constructed in such a way that it may be disengaged by pressing upwardly on the sleeve and downwardly on the base in the region where the abutment is mounted on the base. One or more secondary abutments may be provided on the plastic moulded around the needle to limit the travel of the needle when the locking means is disengaged and/or to provide a finger grip to facilitate manipulation of the sharp into the cocked position. Preferably the device is arranged so that the pointed end of the sharp is surrounded by the sleeve when the sharp is in the rest position. The device may comprise an integral plastics injection moulding incorporating a metal needle. The biasing means may comprise a resilient arm extending from the base, the sharp being housed in a sharp carrier mounted on said resilient arm. The invention will now be described, by way of example, with reference to the accompanying drawings, in which:- Figure 1 is an elevation of a blood letting device according to the invention; Figure 2 is a sectional elevation of the device; Figure 3 is an end elevation; and Figure 4 is an underneath view of the device. The reference numerals in the drawings represent the following parts: 1. Blood letting device 2. Base 2a. Serrations 3. Sleeve 4. Bore 5. Aperture 6. Recess 7. Hinge 9. Arm 21. First abutment 22. Resilient arm 24. Sharp carrier 25. Finger grips 25a. Finger grip 26. Sharp 27. Point 28. Removable cover 29. Break point 30. Second abutment 31. Arrow 42. Latch element 43. Latch element DETAILED DESCRIPTION WITH RESPECT TO THE DRAWINGS Referring to Figures 1 - 4, the blood letting device generally designated 1 may be formed from any suitable material although it is preferred that the material be a plastic material which is capable of being injection moulded. The injection moulding is preferably as an integral unit with the exception of the needle defining the sharp which may comprise a separate component. The blood letting device includes a base 2 which may be provided with means to assist gripping such as the serrations 2a. A sleeve 3 having a bore 4 is located in an aperture 5 formed in the base, the sleeve preferably being provided with an annular recess 6 which may be shaped to assist the blood letting operation. Thus, the shape of the recess 6 will be such that when a finger or other portion of the anatomy is pushed upwards towards the bore 4, the recess will facilitate bulging of the portion of skin in the bore, thus making it more accessible to being pricked. A hinge 7 which may simply comprise a bridge joining the sleeve 3 to the base 2. This hinge is preferably integrally formed in the moulding of the plastic forming the blood letting device and, as the preferred plastic will be a resilient material, the hinge will resiliently permit relative movement between the sleeve 3 and the base 2 when pressure is applied to the sleeve by a finger. An arm 9 is formed at the end of the base 2, and a first abutment 21 mounted on the base in the region of the arm. A resilient arm 22 extends from and is preferably integral with the base 2 in the manner illustrated. This resilient arm terminates in the integrally formed sharp carrier 24. The sharp carrier may be formed with a plurality of finger grip mouldings 25 in the manner illustrated. The lowermost finger grip 25a may also act as an abutment co-operating with the first abutment 21 to limit downward movement of the sharp carrier during operation. A sharp 26 which may comprise a metal needle is encased in the sharp carrier 24, the sharp having a point 27 also encased in the removable cover 28 integrally attached to the sharp carrier. As the sharp is enclosed in plastic by being moulded in situ in an injection moulder, the heat of the plastic used in the injection moulding process should be sufficiently high to sterilise the point of the sharp 27 and thus maintain it in sterilised condition until the removable cover 28 is broken off. To facilitate removal of the removable cover from the sharp and the sharp carrier, a region of reduced plastic thickness defining a break point 29 may be provided. The second abutment 30, is arranged to lock the sharp carrier in a cocked position when the sharp carrier is pulled upwards so that the second abutment 30 is higher than and rests on the first abutment 21. The base 2 and the sleeve 3 are respectively provided with latch elements 42 and 43, the latch elements being shaped to interact in such a way that when the sleeve 3 is pushed upward, the latch element 43 will sit atop the latch element 42 to prevent the sleeve returning to its original position thereby giving a visual indication that the device has been used. To operate the device, the user twists the removable cover 28 to break it off at the break point 29 and pulls it downwardly off the point 27 of the sharp 26. Following this the user pulls upwardly on the finger grips 25 to bring the level of abutment 30 above the level of first abutment 21 thereby locking the device in the cocked position. Upwards finger pressure is then applied to the sleeve whilst at the same time applying downward pressure on the arm 9. This has the effect of pushing the skin of the finger up into the bore 4 whilst at the same time disengaging the locking action caused by the interaction of the abutments 30 and 21. Thus the sharp carrier is suddenly released and moves rapidly down to push the point 27 of the sharp through the skin of the user, the lowermost finger grip 25a restricting the extent to which the point 27 may move downwardly. Having pierced the finger of a user, the point returns to its rest position illustrated in the drawings in the region of the aperture surrounded by the sleeve 3 safely out of harms way should the device accidentally bump against a person during disposal. At the same time, the sleeve 3 will be locked in a twisted position by the interaction of the latch elements 42 and 43 to indicate that the device has been used. In addition, the absence of a cover also provides a visual indication that the device has been used. Other indicator means may also be used to show that the device has been used. These may take the form of a plurality of frangible bridges (not shown) extending between the base around the sides of the aperture 5 to join with the sleeve 3. Finally it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements or parts without departing from the ambit of the invention.

Claims: A blood letting device (1) comprising a base (2), an aperture (5) in the base, a sleeve (3) fitting within the aperture, arranged to turn from an original position about a hinge (7) when the device is used, a sharp (26) with a pointed end (27), having a rest position and a cocked position, biasing means (22) adapted to rapidly urge said sharp from said cocked position to said rest position, and locking means (21,30) adapted to hold said sharp in said cocked position, wherein the arrangement is such that release of said locking means causes the sharp in moving to said rest position, to prick skin which has been held in the region of said aperture, characterised in that a first latch element (42) is provided on the base and a second latch element (43) is provided on the sleeve, the latch elements being shaped such that when the sleeve is pushed upward, the second latch element will sit atop the first latch element so as to prevent the sleeve from returning to its original position. A blood letting device as claimed in Claim 1, wherein the sleeve extends below the base. A blood letting device as claimed in Claim 1, wherein, when the device is intended for use in pricking fingers it is preferred that the internal diameter of the sleeve falls within the range 0.35 to 0.70 cm, more preferably 0.50 to 0.60 cm. A blood letting device as claimed in Claim 1, wherein the lower end of the sleeve has a recess (6) therein which will cause the skin to bulge up within the sleeve as the skin is pressed towards the sleeve so as to bring the skin into proximity with the sharp. A blood letting device as claimed in Claim 1, wherein tamper indicating means may comprise one or more frangible bridges extending between the sleeve and base, said bridge or bridges breaking when the sleeve is turned about the hinge during use. A blood letting device as claimed in Claim 1, wherein the biasing means comprises a resilient arm (22) extending from the base. A blood letting device as claimed in Claim 1, wherein the sharp is provided with a removable cover (28) which protects the user from accidental sticking during handling and maintains a piercing point forming part of the sharp in sterile condition. A blood letting device as claimed in Claim 7, wherein the sharp comprises a pointed metal needle moulded in place in plastics using an injection moulder and at the same time the cover is moulded in place as well, such that the needle is substantially enclosed in plastic. A method for sterilising a sharp of the blood letting device according to Claim 8, wherein sterilisation is achieved due to the heat of the injection moulding process.

Inventors: BRAKEY DALE ROBERT, MEDIGATE MANUFACTURING PTE LTD, BRAKEY, DALE ROBERT
Applicants: BRAKEY DALE ROBERT, BRAKEY, DALE ROBERT
Application year: 1996
Main classification: A61B5
IPC codes: A61B5