Abstract:
The present invention generally relates to an automatic lancing device for withdrawing a blood sample, comprising a pushing member positioned at a back end of a body and a rotatable cap combined with a front end of the body for regulating the combination length of the body and the ejection length of a lancet, thereby obtaining a blood sample exactly at a desired position without misoperation and adjusting the penetration length of lancet according to depth of the skin.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to a lancing device for withdrawing a blood sample for medical treatment, and more particularly, to an automatic lancing device obtaining a blood sample exactly at a desired position without misoperation and adjusting the penetration length of lancet according to depth of the skin. 
   2. Description of the Prior Art 
   Generally, a lancing device is used when a small amount of blood is needed in medical treatment procedures, such as blood type test or blood sugar test. 
   In the conventional lancing device, as shown in  FIG. 5 , a lancet (not shown) receiving an elasticity generated by an elastic member, such as spring (not shown), is mounted within a case  50 . The lancet is automatically ejected from the front end of the case  50  by means of elasticity of the elastic member, thereby piercing the skin at a predetermined depth. The lancing device elongates the elastic member positioned at the inside of the case  50  by moving an operating member  52  positioned at a back end of the case  50  to the rear. A pushing member  51  is formed to protrude from one side of the case  50 . When the protruded pushing member is pushed, the spring is contracted and generates the elasticity. By means of the said elasticity, The lancet is ejected from the front of the case, thereby piercing the skin. After the lancet pierces the skin, the elastic member retracts the lancet to a safe position within the lancing device. 
   However, the ejection length of the lancet in conventional the lancing device cannot be regulated. As a result, in order to obtain blood sample at the skin having different depth, a lancing device comprising a lancet having a different ejection length should be used. Furthermore, because the pushing member  51  generating instant impact to the lancet is located at one side of the case  50 , a user happens to push the pushing member  51  by mistake when seizing the case  50 , thereby piercing an undesired place of the skin. 
   SUMMARY OF THE INVENTION 
   Accordingly, an object of the present invention is provide an automatic lancing device that can obtain a blood sample exactly at a desired place by disposing a pushing member at a back end of a body, and regulate the ejection length of the lancet from body corresponding to depth of the skin. In order to achieve the above-described object, An automatic lancing device for withdrawing a blood sample, comprising: a hollow cylindrical body; an operation mechanism having a lancet exchangeably fitted at the front of a lancet holder positioned inside the body, and an impact-receiving member combined with the other side of the lancet holder and receiving impact to eject the lancet from the body; an impact-generating mechanism having an impact-transmitting member positioned at a back end of the operation mechanism and transmitting impact to the impact-receiving member; and a length-regulating mechanism comprising a length-regulating member rotationably combined with the outer circumference of a front case enclosing the lancet at the front end of the body and regulating a ejection length of the lancet from the front case. 
   The automatic lancing device according to the present invention is characterized in that the impact-generating mechanism comprises: a pushing member being positioned at the back end of the body and having pin-operating holes which penetrate across it; an impact-transmitting member having a penetrating hole and inner-inserted into inside the pushing member, wherein a first elastic member is also inner-inserted inside the pushing member and interposed between the impact-transmitting member and the pushing member; a pin guide member having pin guide holes penetrating across it and outer-inserted into outside the pushing member, wherein a second elastic member is also outer-inserted outside the pushing member and interposed between the pin guide member and the pushing member; and an operating pin passing through the penetrating hole of the impact-transmitting member, the pin-operating hole of the pushing member and the pin-guide hole of the pin guide member and connecting these members. 
   The automatic lancing device according to the present invention is characterized in that: wherein each of pin guide holes has a circumferential path and an longitudinal path; the operating pin located at the circumferential path is moved into the longitudinal path by the pin-operating hole when the pushing member is pushed; and the impact-transmitting member is moved forward with the operating pin according to the longitudinal path due to the first elastic member storing elasticity while the operating pin is being moved, and transmits impact into the impact-receiving member. 
   The automatic lancing device according to the present invention is characterized in that the length-regulating mechanism comprises a front case having a helical thread at the outer circumference and the length-regulating member has a protruding portion for moving according to the helical thread. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be explained in terms of exemplary embodiments described in detail with reference to the accompanying drawings, which are given only by way of illustration and thus are not limitative of the present invention, wherein: 
       FIG. 1  is an exploded perspective view of an automatic lancing device according to the present invention; 
       FIG. 2  is a cross-sectional view of an automatic lancing device according to the present invention; 
       FIG. 3  is an operation state view of an automatic lancing device according to the present invention; 
       FIG. 4  is a assembly plane view of an automatic lancing device according to the present invention; and 
       FIG. 5  is a perspective view of a conventional lancing device. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIG. 1 , an automatic lancing device according to the present invention broadly comprises a hollow cylindrical body  13 , an operation mechanism  10  ejecting a lancet  11  instantly to the fore of the body  13  and piercing the skin, an impact-generating mechanism  20  positioned at the back of the operation mechanism  10  and generating instant impact triggering the operation mechanism  10 , and a length-regulating mechanism  30  positioned at the front end of the operation mechanism  10  and regulating the ejection length of the lancet  11 . 
   As shown in  FIGS. 1 and 2 , an operation mechanism  10  has a lancet holder  12  that is inserted into the hollow cylindrical body  13  and a lancet  11  exchangeably fitted at the front of the lancet holder  12 . An impact-receiving member  15  is inserted into a return elastic member  14  positioned in the inside of the body  13 . The front end of the impact-receiving member  15  is combined with the lancet holder  12 . When instant impact generated in the impact-generating mechanism  20  is transmitted into the impact-receiving member  15 , the impact-receiving member  15  is moved forwardly. As a result, the lancet  11  connected to the impact-receiving member  15  by way of the lancet holder  12  is moved forwardly. At this time, the return elastic member  14  is contracted with accumulating elasticity, and then instantly is bounced backward. As a result, the lancet  11  instantly pierces the skin and then is retracted. 
   As shown in  FIGS. 1 and 3 , the impact-generating mechanism  20  has a pushing member  25  inserted and positioned at the back end of the body  13 , and a back case  26  covering the pushing member  25  to prevent separation of the pushing member  25  from the body  13  and combined with the body  13 . A first elastic member  23  for giving elasticity to an impact-transmitting member  22  is inserted into the hollow and cylindrical pushing member  25 . The impact-transmitting member  22  is also inner-inserted into the pushing member  25  and positioned at the front of the first elastic member  23 . The impact-transmitting member  22  has a penetration hole  221  penetrating across it, and an operating pin  220  is inserted in the penetration hole  221 . Here, it is preferable that the length of the operating pin  220  is longer than that of the penetration hole  221 , that is, diameter of the impact-transmitting member  22 . 
   Pin-operating holes  250  are formed symmetrically on the cylindrical surface of the pushing member  25 . Each of pin-operating holes  250  has a skew parallelogram shape. 
   A second elastic member  24  outer-inserted on the circumference of the pushing member  25  is contracted when the pushing member  25  is pushed, and elongated to return the pushing member  25  to the original position when the pushing force is removed. 
   A pin guide member  21  is fixed at a predetermined position within the body  13  and, is also outer-inserted onto the pushing member  25  and positioned at the front of the second elastic member  24 . Therefore, the second elastic member  24  can be contracted with accumulating elasticity when a user pushes the pushing member  25 , because it is supported at the back end of the pin guide member  21 . Pin guide holes  210  is formed symmetrically on the circumference surface of the pin guide member  21  and each of them has a longitudinal path  210   a  and a circumferential path  210   b . The both ends of the operating pin  220  inserted into the impact-transmitting member  22  are being bridged through the pin guide hole  210 , and moved according to the path of the pin guide hole  210 . When positioned at the circumferential path  210   b  of the pin guide hole  210 , the longitudinal movement of the operating pin  220  is restrained (see (a) of  FIG. 3 ). 
   Referring to (a) of  FIG. 3 , the impact-transmitting member  22  inner-inserted and the pin guide member  21  outer-inserted in the pushing member  25  are combined using the operating pin  220  penetrating the penetration hole  221 . That is, the operating pin  220  penetrating the impact-transmitting member  22  passes through the pin-operating hole  250  formed on the pushing member  25  wrapping the outside of the impact-transmitting member  22 . The operating pin  220  is then inserted in the pin guide hole  210  formed on the pin guide member  21  wrapping the pushing member  25 . When the pushing member  25  is not pushed, the operating pin  220  is placed at the circumferential path  210   b  of the pin guide hole  210  on pin guide member  21 . 
   Thereafter, when the pushing member  25  is pushed, the impact-transmitting member  22  cannot be moved according to the longitudinal direction (forward and backward) because the crooked hole  210  restrains the longitudinal movement of the operating pin  220 . Since the pin guide member  21  is fixed at the body  13 , the first and the second elastic members  23  and  24  are contracted and the pushing member  25  is only moved forwardly. As the push member  25  moves, the back sloping side  250   a  of the pin-operating hole  250  formed on the pushing member  25  presses the operating pin  220 . Then, the operating pin  220  is moved according to the circumferential path  210   b  to the longitudinal path  210   a  of the pin guide hole  210  (see (b) of  FIG. 3 ). 
   Thereafter, the contracted first elastic member is instantly elongated to the fore, and the operating pin  220  is moved forwardly according to the longitudinal path  220   a  together with the impact-transmitting member  22 . Then, the impact-transmitting member  22  hits the impact-receiving member  15  (see (b) of  FIG. 3 ). As a result, the lancet  11  combined with the front end of the impact-receiving member  15  is instantly ejected outwardly. 
   When the pressure of the pushing member  25  is removed, the contracted second elastic  24  is elongated, and moves the pushing member  25  to the back end. As the pushing member  25  is moved, the operating pin  220  is pressed by the front sloping surface  250   b  of the rising pin-operating hole  250 . The operating pin  220  is then moved to the circumferential path  210   b  from the longitudinal path  210   a , thereby the longitudinal movement is restrained. 
   Referring to  FIGS. 1 and 4 , the length-regulating mechanism  30  is joined with the front end of the body  13  to cover the lancet  11  and the lancet holder  12 . The length-regulating mechanism  30  has a front case  33  removably combined with the outer circumference of the body  13 . As a result, the lancet  11  is easily exchanged by separating the front case  33  from the body  13  and removing the lancet  11  from the lancet holder  12 . A helical thread  330  is formed on the outer circumference of the front case  33 . A hollow cylindrical length-regulating member  32  having a protruding portion  320  for moving according to the thread  330  is combined with the front case  33 . A cap  31  is fixed at the outer circumference of the length-regulating member  32 , and encloses the length-regulating member  32 . As shown in  FIG. 4 , when the cap  31  is rotated, the length-regulating member  32  rotates together according to the helical thread  330 . As a result, when the cap  31  and the length-regulating member  32  are moved forwardly, the combination length between the cap  31  and the front case  33  is getting far and closes. As the combination length is changed, the length from the lancet  11  in the inside of the front case  33  to the leading end of the cap  31  increases or decreases. Therefore, the ejection length of the lancet  11  instantly ejected from the outside of the cap  31  by pushing the pushing member  25  can be regulated. 
   As discussed earlier, in the automatic lancing device of the present invention, the pushing member generating instant impact due to elasticity of the elastic member is positioned at the back end of the body, thereby preventing misoperation when a user happens to seize the body. The ejection length of the lancet can be regulated by rotating the cap and the length-regulating member combined with the front of the body. As a result, the automatic lancing device can be used at the skin having different thickness only by simply rotating the cap.