Abstract:
An adjustable endcap for a lancing device includes a basecap and a twistcap. The basecap includes a post with detents thereon. At least one finger is provided on the basecap adjacent the post. The twistcap includes at least one helical track on its outer surface into which the finger extends when the twistcap is mounted on the post. The twistcap also includes a plurality of grooves on an inner surface for engagement with the detents. As the twistcap is rotated on the post, the interaction of the finger and track causes the twistcap to move toward and away from the basecap and to adjust the penetration depth of a lance reciprocally mounted in the lancing device.

Description:
this application claims the benefit of provisional application 60/229,383 filed Sep. 1, 2000. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to blood monitoring devices, and, more particularly, to an adjustable endcap for lancing devices used to lance a finger or other areas of the body to harvest blood for monitoring. 
     BACKGROUND OF THE INVENTION 
     It is often necessary to quickly obtain a sample of blood and perform an analysis of the blood sample. One example of a need for painlessly obtaining a sample of blood is in connection with a blood glucose monitoring system where a user must frequently use the system to monitor the user&#39;s blood glucose level. 
     Those who have irregular blood glucose concentration levels are medically required to regularly self-monitor their blood glucose concentration level. An irregular blood glucose level can be brought on by a variety of reasons including illness such as diabetes. The purpose of monitoring the blood glucose concentration level is to determine the blood glucose concentration level and then to take corrective action, based upon whether the level is too high or too low, to bring the level back within a normal range. The failure to take corrective action can have serious implications. When blood glucose levels drop too low—a condition known as hypoglycemia—a person can become nervous, shaky, and confused. That person&#39;s judgment may become impaired and they may eventually faint. A person can also become very ill if their blood glucose level becomes too high—a condition known as hyperglycemia. Both conditions, hypoglycemia and hyperglycemia, are potentially life-threatening emergencies. 
     One method of monitoring a person&#39;s blood glucose level is with a portable, hand-held blood glucose testing device. In order to check the blood glucose level with the testing device, a drop of blood is obtained from the fingertip using a lancing device. A typical lancing device contains a needle lancet to puncture the skin. Some of these lancing devices have no means of adjusting the depth of penetration of the lancet. These lancing devices cannot accommodate different skin thicknesses which impacts the amount of blood that can be drawn. In addition, these devices cannot accommodate differences in pain tolerances of the person whose blood is being drawn. 
     Although there are adjustable lancing devices, these devices typically adjust the position of a structural element that engages a lancet holder thereby limiting the travel of the lancet. These are cumbersome to adjust and are subject to rapid deterioration. Other adjustable lancing devices have multiple parts resulting in high costs, and complicated adjustment procedures. 
     SUMMARY OF THE INVENTION 
     The present invention is an endcap for a lancing device that adjusts the penetration depth of a lancet in a lancing device allowing the lancing device to be adjusted to accommodate skin thickness and pain tolerance of the person on whom the lancing device is used. The endcap contains adjustment structure and is adapted to fit on an existing lancing device thus reducing the cost. 
     The endcap of the present invention consists of only two parts, a basecap and a twistcap. Because there are fewer parts than prior art adjustable lancing devices, the cost is reduced and the assembly and use of the endcap of the present invention are simplified. The basecap includes a central post on which the twistcap is mounted. The lancet of the lancing device when triggered, extends through the basecap, across the distance between the basecap and the twistcap, and through and beyond the twistcap. The end of the twistcap is the portion of the endcap that is pressed against the skin of the person from whom blood is to be drawn. The twistcap includes external helical tracks into which fingers on the basecap extend. To adjust the endcap, a user merely needs to twist or rotate the twistcap and the interaction of the fingers and helical tracks moves the twistcap relative to the basecap. The distance the lancet of the lancing device extends beyond the basecap is constant. Therefore, by adjusting the distance between the basecap and twistcap by twisting the basecap, the distance the lancet extends out of the twistcap and into a user&#39;s finger is adjusted. Consequently, the user of a lancing device that has an endcap of the present invention can easily adjust the depth of penetration of the lancet merely by rotating or twisting the endcap. There are stops that can be felt and heard by a user as the twistcap is rotated. These stops correspond to different penetration depths and are provided by detents on the central post of the basecap and detent slots on the inside of the twistcap. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects and advantages of the invention will become apparent upon reading the following detailed description in conjunction with the drawings in which: 
     FIG. 1 is a top plan view of a prior art lancing device, 
     FIG. 2 is an enlarged perspective view of the lancing device of the present invention; 
     FIG. 3 is a perspective view of the endcap for the lancing device of the present invention; 
     FIG. 4 is a perspective view of the endcap illustrated in FIG. 3 with the twistcap removed; 
     FIG. 5 is a front plan view of the endcap illustrated in FIG. 4; 
     FIG. 6 is an enlarged perspective view of the twistcap; and 
     FIG. 7 is an enlarged cross sectional view of the twistcap illustrated in FIG.  6   
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Many children and adults must draw their blood several times a day to perform an analysis of the blood sample drawn. Skin thickness and tolerance to pain differs among these people and a device for lancing a person&#39;s skin to draw blood preferably includes a mechanism that allows adjustment of the depth of penetration of the lance. An example of a known lancing device  100  is shown in FIG.  1 . The known lancing device  100  is disclosed in U.S. Pat. No. 5,954,738 and is incorporated herein in its entirety by reference. The known lancing device  100  includes a main housing portion  112 , a housing portion  114  movable relative to the main housing portion  112  and an endcap support  116 . An end cap  118  may be attached onto the endcap support  116  by a pair of latching or support arms  120  which are part of the endcap support  116 . 
     A lancing mechanism including a lance is mounted inside the main housing portion  112 . The lance is driven through an opening in the endcap  118  by a driving mechanism that is cocked by pulling the housing portion  114  away from main housing portion  112 . The driving mechanism is fired by pushing a button  122 . The known lancing device  100  is provided with a number of different sized endcaps  118  to vary the penetration depth of the lance. 
     The lancing device  10  of the present invention is shown in FIGS. 2-7. The lancing device  10  is the same as the known lancing device  100  in that it includes a main housing portion  12 , a housing portion  14  that is movable relative to the main housing portion, an endcap support  16  and a button  22  for firing a driving mechanism and lancing mechanism housed in the main housing portion  12 . The lancing device  10  differs, however, from the known lancing device  100  in that it does not require a number of different sized endcaps to vary the penetration depth of a lance. Instead, the lancing device  10  includes an adjustable endcap  18  that can be adjusted quickly and easily for multiple lance penetration depths. 
     The endcap  18  is a two piece assembly consisting of a basecap  24  and a twistcap  26 . The twistcap  26  includes a top or face  28  that is placed on the skin of the person whose blood is to be drawn. There is an opening  30  in the top  28  through which a lance is driven when the button  22  is depressed. By varying the position of the top  28  relative to the basecap  24 , the distance the lance extends out of the twistcap  26  and thus the penetration depth of the lance can be adjusted. 
     To provide the lancing device  10  with quick adjustment of the penetration depth, the basecap  24  may be snapped onto a pair of support arms (not shown) similar to the support arms  120  on the known lancing device  110 . As best seen in FIGS. 4 and 5, the basecap  24  includes a body  32  with a pair of shoulders  34  and  36 . The shoulders  34  and  36  are hollow and fit over the support arms on the lancing device  10 . Indicia  38  is provided on the top of the body  32  to indicate the different penetration depths of the lance. The basecap  24  further includes a column or post  40  located between and spaced from the shoulders  34  and  36 . The post  40  includes a top  42  with a central opening  44  through which the lance extends. The post  40  also includes first  46  and second  48  cantilevered detents. A pair of protrusions or fingers  47  and  49  are formed on the inside surfaces of the shoulders  34  and  36  and extend toward the post  40 . 
     The twistcap  26  fits over and onto the column or post  40 . As best illustrated in FIGS. 3,  6  and  7 , the twistcap  26  includes several ribs  50  that provide a gripping surface allowing a user to grip and rotate the twistcap  26  relative to the post  40  and the basecap  24 . The twistcap  26  also includes an indicator line  52  that points to a different portion of the indicia  38  as the twistcap  26  is rotated thereby indicating the depth of penetration of the lance at that position of the twistcap  26 . 
     A first helical groove  54  and a second helical groove  56  are formed in the lower outside surface of the twistcap  26 . The grooves  54  and  56  are located on the twistcap  26  and aligned with a protrusion or finger  47  and  49  extending into a respective groove  54  and  56  when the twistcap  26  is placed on and over the post  40 . 
     As best illustrated in FIG. 7, several slots  58 ,  60 ,  62 ,  64  and  66  are formed in the inner peripheral surface  68  of the twistcap  26 . When the twistcap  26  is placed on the column or post  40  and rotated, the detents  46  and  48  snap into the slots  58 ,  60 ,  62 ,  64  and  66  to indicate to the user a specific penetration depth of the lance. In the illustrated embodiment, the indicia  38  includes a first symbol  38   a  in the form of a large drop and a second symbol  38   b  in the form of a smaller drop. Between the first symbol  38   a  and the second symbol  38   b  are five dot indicia  38   c.  These dot indicia  38   c  correspond to specific penetration depths varying from shallow (those dot indicia  38   c  closest to the small drop indicia  38   b ) to deeper (those dot indicia  38   c  closest to the large drop indicia  38   a ). A person can select the depth of penetration by twisting the twistcap to align the indicator line  52  with the dot indicia  38   c  that corresponds with the preferred depth of penetration. 
     In addition to this visual selection of the lance penetration depth, a tactile and audible indication is also provided by the detents  46  and  48  and the slots  58 ,  60 ,  62 ,  64  and  66 . Each slot  58 ,  60 ,  62  and  64  corresponds to one of the dot indicia  38   c.  As a user rotates the twistcap  26  one of the detents  46  and  48  is moved out of one of the slots  58 ,  60 ,  62 ,  64  and  66  and the user feels a slight resistance to the rotating action. Further rotation moves the slot  58 ,  60 ,  62 ,  64  and  66  past the detent and the smooth inner peripheral surface  68  of the twistcap  26  passes over the detent. As the next slot  58 ,  60 ,  62 ,  64  or  66  passes over the detent, the detent snaps into the slot producing an audible clicking sound and the user feels a resistance to rotation. In this way the user knows when a specific penetration depth has been reached. As can be understood, adjustment of the penetration depth is easy and multiple penetration depths are possible without need to add or remove parts to the lancing device  10  or to vary the pressure by which the lancing device  10  is pressed against a user&#39;s skin. 
     The penetration depth of the lance is shallower the greater the distance between the face  28  of the twistcap  26  and the top  42  of the column or post  40 . This distance is adjusted by the interaction of the protrusions or fingers  47  and  49  in the first and second grooves  54  and  56 . As the twistcap  26  is rotated, the first and second grooves  54  and  56  are moved relative to the protrusions or fingers  47  and  49 . Because the first and second grooves  54  and  56  are helical, the movement of the grooves  54  and  56  relative to the protrusions  47  and  49  causes the twistcap  26  to move longitudinally relative to the column or post  40  thereby decreasing or increasing the distance between the face  28  of the twistcap  28  and the top  42  of the column or post  40 . Because the lance extends beyond the top  42  a fixed distance, as the distance between the top  42  and the top  28  is increased, the distance the lance extends beyond the top  28  is decreased, and as the distance between the top  42  and top  28  is decreased, the distance the lance extends beyond the top  28  and thus, the penetration depth, is increased. 
     While the present invention has been described with reference to one or more particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims.