Abstract:
A lancing device includes a main housing  28  having in the forward upper end thereof a loading bay for receiving a capped lancet  12/20 . The loading bay is closed by a cover  34  which is pivotally and slideably moveable in the housing. Closing the cover and then pushing it rearwardly causes the lancet body  12  to be pulled rearwardly clear of the cap  20  thereby exposing the lancet needle. Further rearward movement of the shifts the lancet cover into a battery position ready to be driven forwardly by a drive mechanism when fired.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to lancing devices and in particular, but not exclusively, to such devices for use with a disposal lancet having a removable cap. 
     2. Description of the Related Art 
     There are many applications where a user needs to draw a bead of blood regularly for test purposes. It is known to provide lancing devices with disposable lancets for this purpose. One conventional form of lancet is provided with a moulded-on cap which keeps the lancet tip sterile and also protects the user when loading the lancet into the device. It is also known to use the same cap to cover the tip of the lancet after use and prior to disposal thereof. In our co-pending application WO2006/128752 we disclose a lancet having a body and a tip and a cap which is bonded to the body by a relatively weak bond so that the cap can be easily slid off the lancet body. This obviates the need for the twisting off action of the previously described type of lancet. 
     In conventional lancing devices, the lancet is pushed rear end first into the lancet holder within the lancing device with pressure being applied on the front end of the lancet. Although the provision of a moulded-on cap normally shrouds the needle, there is a risk that the pushing action may damage the needle contained under the moulded-on cap or, at worst, the cap may slip off prematurely exposing the lancet tip. Given the small size of lancing devices, the lancet cap can be quite small and therefore awkward for those of reduced dexterity to remove. Accordingly, there is a need for a lancing device in which uncovering of the lancet tip is done automatically, and preferably within the lancing device itself. 
     SUMMARY OF THE INVENTION 
     Accordingly, in one aspect, this invention provides a lancing device for receiving in use a lancet having a removable cap, said device including: 
     a housing; 
     a loading station adapted to receive in use said lancet; 
     a drive disposed within said housing and actuable to fire said lancet in use momentarily to project its tip from the device; 
     an uncapping arrangement for uncapping said lancet in use when in said housing, and 
     a transfer arrangement for moving said lancet in use from said loading station to an in-battery position ready to be fired by said drive. 
     In the above arrangement a lancet with a removable cap is loaded in use into said loading station and the removable cap is removed by the uncapping means, with the lancet being moved to an in-battery position. 
     Preferably, said means for uncapping said lancet includes retaining means for retaining said cap relative to said housing, and means for moving said lancet relative to said housing to remove said cap in an uncapping phase of movement. 
     Preferably, said lancing device includes means for recapping said lancet with said removable cap within said housing after firing. 
     Preferably, said loading station is at a forward region of said housing, and said uncapping means moves said lancet rearwardly to uncap it. 
     Preferably, said loading station is offset from the firing axis along which the lancet tip moves when fired, and said uncapping means in use shifts said lancet to align it generally with said firing axis during or after said rearward movement. 
     Preferably, said uncapping means includes a moveable cover moveable between an open position in which in use said lancet with its removable cap may be inserted into said loading station, and a closed position in which said loading station, and a lancet contained therein, is generally covered. 
     Preferably, said moveable cover is captive to said housing and mounted for pivotal movement between said open and closed positions. Advantageously, the cover is additionally slideable relative to said housing, the cover when in the closed position being engageable with a lancet in use to transmit longitudinal movement thereto. 
     In one arrangement, where the lancet includes a lateral drive lug on each side thereof, said cover preferably includes drive surfaces to engage said drive lugs as said cover is slide rearwardly after closing. The cover also conveniently includes an ejection surface adapted in use to lift the rear of a lancet when the cover is open. The cover may be transparent or opaque. 
     Preferably, said loading station comprises a recess defined within said housing, said recess including guide means for guiding said lancet in use for rearward uncapping movement, and being complimentarily shaped with respect to said lancet such that said lancet is moved towards said firing axis after a pre-set extent of longitudinal movement. 
     Where the lancet has transverse drive lugs, the housing may conveniently include a guide surface with cut outs to allow passage of said lugs as said lancet moves towards said firing axis. 
     The device conveniently includes a lancet carriage disposed to receive said lancet in use and to align it with said firing axis, said lancet carriage being moveable against a bias from an equilibrium position in which the lancet tip is within said housing to a projecting position in which the lancet tip projects from said housing. 
     The drive means may take various forms but may conveniently comprise a hammer mounted for sliding movement within said housing for movement against the bias of a drive spring from an equilibrium position to a latched, cocked position, and trigger means for unlatching said hammer. 
     In another aspect, this invention provides a lancing device for receiving in use a lancet having a removable cap, said device including: 
     a housing; 
     a loading station adapted to receive in use said lancet; 
     a drive disposed within said housing and actuable to fire said lancet in use momentarily to project its tip from the device, and 
     an arrangement for uncapping said lancet in use when in said housing. 
     In another aspect, this invention provides a lancet comprising a main body of strip form with a cap, the body and cap having respective drive surfaces for engagement in use by the housing and lancet carriage of a lancing device as described above. 
     In yet another aspect, this invention provides a lancet having an elongate main body portion, a tip, and a cap portion for covering said tip, at least one of said main body portion and said cap portion having a resilient engagement element for allowing said cap to be removed and reapplied by relative longitudinal movement. 
     Whilst the invention has been described above, it extends to any inventive combination set out above or in the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The invention may be performed in various ways, and an embodiment thereof will now be described by way of example only, reference being made to the accompanying drawings, in which 
         FIG. 1  is a view of a disposable lancet with a removable cap for use in the lancing device illustrated in  FIGS. 2 to 14 ; 
         FIG. 2  is a perspective view of a lancing device of this invention with the lancet in the loading station; 
         FIGS. 3 to 7  are side views of the lancing device with the right hand housing removed showing the steps of loading a lancet into the loading bay, closing the cover and pushing the cover rearwardly to move the lancet into a loading carriage; 
         FIGS. 8 and 9  are side views with the left hand housing half removed showing cocking of the device and firing respectively; 
         FIGS. 10 and 11  show the device when the cover is shifted forwardly to move the used lancet out of the lancet carriage back to the loading station; 
         FIG. 12  is an exploded view of the lancing device and the lancet; 
         FIG. 13  is a side section view; 
         FIG. 14  is a top plan view with part of the cover removed for clarity; 
         FIGS. 15 ,  16 ,  17   a  and  17   b  are views of an alternative form of a disposable lancet with a removable cap for use in this invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring initially to  FIG. 1  there is a shown first form of re-cappable lancet in accordance with an aspect of the invention. The lancet  10  has a main body  12  of generally rectangular strip form encasing a needle whose tip  14  projects from the forward end of the lancet. The front end of the body is necked at  16  to provide an enlarged head  18 . A cap  20  of similar flat rectangular section has a capping recess  22  designed to snap around the head  18  of the main body. The main body  12  has two pairs of laterally extending drive lugs  24 , and the cap  20  has a pair of similarly dimensioned transverse cap lugs  26 . The cap  20  and the lancet body  12  are designed so that the cap shields a tip and provides a sterile shield for the tip prior to use, the cap being removable and replaceable by pulling it off or pushing it on to the main body longitudinally. The cap and lancet can be produced by a twin shot moulding process whereby a lancet body is injection moulded about the needle leaving the tip protruding from the body and a cap is then overmoulded about the tip of the needle as set out in our published application WO2007/085865. 
     Referring now to  FIG. 2 , the illustrated embodiment of lancing device comprises a main housing made up of two housing halves  28  which contains the drive and trigger mechanism for the lancet which is designed to be driven momentarily to project through the aperture  30  of a nose piece  32  which is threaded into the forward end of the housing to allow axial adjustment of the nose piece and thus the pre-set penetration depth. 
     A transparent cover  34  is captive to the forward upper end of the housing by hinge lugs on the cover running in respective hinge guides  38  on the inner wall of each housing half  28  (see e.g.  FIG. 12 ). The cover  34  is moveable between the open position shown in  FIGS. 2 and 3  to a folded forward position in which it lies generally parallel with the upper surface of the casing, as shown in  FIG. 5 . From here the cover  34  can be pushed rearwardly such that locking ribs  40  engage and slide into locking slots  42  on the housing. 
     When open, the cover  34  reveals the loading station area within the forward end of the lancing device, into which a lancet may be loaded as in  FIG. 2 . When first loaded into the loading station, the lugs  26  of the cap  20  are received in capture recesses  44  formed in the inner walls of the casing halves  28 . The lancet body  12  is supported on a false floor  46  defined by opposed wall sections projecting inwardly of the housing halves  28 . The false floor  46  has a cutaway region  48  through which the lancet  10  may be urged downwardly when it is shifted rearwardly from the loading position as to be described in more detail below. 
     The cover  34  has four trapezoidal shaped guide lugs  50  that have on their rearward surfaces inclined drive faces  52  for engaging the drive lugs  24  on the lancet main body  12 . The cover  34  also has a pair of ejector fingers  54  extending transversely from the axis of the hinge lug which can be seen more clearly in  FIGS. 10 and 12 . When the cover  34  is opened, the ejector fingers upstand from the false floor of the loading station to lift the rear end of the lancet  12  clear of the housing  28 . 
     Located beneath the false floor  46  and generally aligned under the cutaway region  48  is a lancet carriage  56  having a cradle region for receiving the lancet  12  comprising side walls  58  with four slots  60  for receiving the drive lugs  24  of the lancet. The slots  60  have ramped forward surfaces for assisting engagement and disengagement of the lancet with the carriage  56 . 
     The lancet carriage  56  is slideably mounted for longitudinal movement within the casing  28  by means of transverse ribs  62  on each side thereof which engage in respective slots  64  on the interior of the housing halves  28 . The lancet carriage determines the path of the lancet tip  14  (otherwise referred to herein as the firing axis). The lancet carriage is biased rearwardly by means of a compression spring  66  which engages an interior wall  68  of the casing  28  at one end and the base of a spring support stem  70  on the lancet carriage at its other end. The forward and rearward extents of the movement of the carriage  56  are determined by the axial extent of the slots  64 . 
     To the rear of the lancet carriage  56  is a hammer  72  which has lateral ribs  74  which slide in respective slots  76  on the inner walls of the housing  28 . The hammer  72  is urged forwardly by a strong drive spring  78  acting between the rear end of the hammer and the inner rear wall of the housing  28 . It will be noted that the drive spring  70  is stronger than the carriage spring  66  so that, in the rest position shown in  FIGS. 2 to 7 , the hammer is at its forward most position, urging the lancet carriage  56  a little forward of its rearmost position. On its upper surface, the hammer  72  has a forwardly extending resilient latching arm  80  with a latch piece  82  designed to be latched into a latch through-hole  84  formed in an inner wall  85  of the housing, when the hammer is cocked. 
     The hammer is cocked or loaded by means of an externally projecting slider  86  which projects through a slot  88  in the housing and has a forward, downwardly directed tooth  90  that cooperates with a drive rib  92  on the rear end of the hammer  72 . The slide  80  is biased forwardly by a compression spring  94 . 
     An externally accessible trigger button  96  is captive to the upper wall of the housing and has a trigger stem  98  that engages the latch through-hole  84 . When the hammer is latched with the latch piece  82  in the through-hole, pressing the trigger button  96  causes the stem to push the latch piece  82  clear of the latch through-hole so the hammer  72  shoots forwardly to impact the rear of the lancet holder  56  to drive it, and the uncapped lancet  12 , forwardly to cause the lancet tip  14  to project through the nose piece  32 . 
     In use, assuming the device is initially empty, it is made ready for loading by sliding the transparent cover  34  forwardly and flipping it open. A lancet with cap attached is then placed in the loading station, locating the capture lugs  26  on the lancet cap in the capture recesses  44  in the casing, and with the rear of the lancet  12  resting on the ejection teeth  50  ( FIGS. 2 and 3 ). The transparent cover  34  is then hinged forwardly ( FIG. 4 ) to the position shown in  FIG. 5 , where the cover is parallel to the top of the casing with the guide lugs contacting the forward surfaces of the drive lugs of the lancet body. The cover is then pushed rearwardly so that the locating ribs  40  on the sides thereof locate and slide in the locking groove  42  in the housing. As this is happening, the guide lugs  50  engage the drive lugs  24  on the lancet to shift it rearwardly along the false floor  46  to uncap it, with the rear end of the lancet the main body  12  coming to rest against an internal wall  45 . With further rearward movement in this plane prevented, the continued rearward movement of the cover  34  causes the drive surfaces  52  to cooperate with the drive lugs  24  on the lancet body to push it downwardly through the cutaway region so that the lugs  24  engage the slots  60  and ride down the ramp surfaces thereof so that the lancet portion is cradled by the lancet carriage  58  ( FIGS. 6 and 7 ). 
     The hammer is then cocked by sliding the slider  86  rearwardly which pulls the hammer  72  rearwardly by co-engagement of the drive teeth  90 ,  92 , until the latch piece  82  engages in the latch through-hole  84  thereby cocking the device. This slide is released to return to its original position ( FIG. 8 ). 
     When the user is ready, and the device positioned against the skin, the button  96  is pressed which unlatches the latch piece  82  from the through-hole  84  so that the hammer  72  shoots forwardly, to impact the rear of the lancet carriage  56  which travels forwardly to project the lancet tip  13  through the nose piece  30 , compressing the lancet carriage spring  66 . The lancet carriage is then immediately returned to its equilibrium position by the spring  66 . 
     After firing, the transparent cover  34  is slid forwardly so that the ejection fingers  54  pull the lancet main body portion clear of the lancet carriage, back through cutaway region  48  hence to move along the false floor  46  to re-engage the lancet with the cap so that the cap clips back onto the lancet into place. The cover is then flipped over and the ejection fingers  54  lift the rear end of the lancet clear of the housing. 
     Referring now to  FIGS. 15 to 17 , there is shown another embodiment of the lancet for use in this invention. The lancet&#39;s main body portion is of similar design to that shown in  FIG. 1 . In this embodiment, the cap is separate, and modified to safeguard sterility of the tip and to make re-capping of the lancet easier. The lancet body is modified so that it defines a short cylindrical portion  19  at the top of the head where the tip exits  14 . The lancet cap  20  is provided with a cylindrical shell part  21  which fits over the cylindrical portion  19 . The cap also is retained by means of rearwardly extending arms  23  which snap fit around the neck.