Abstract:
An automatic safe disposable blood sampling device includes a casing with a launching chamber formed therein. The launching chamber has a lancet needle-exiting hole at a front end thereof; a lancet needle arranged inside the launching chamber; a spring; a launching mechanism composed of the spring and a catch-launching mechanism; a press-launching mechanism provided on the casing; and a self-locking mechanism composed of barbs provided on the press-launching mechanism and self-locking hooks or notches provided on the casing which engage corresponding barbs. When pressed, the press-launching mechanism triggers the catch-launching mechanism, to disengage the lancet needle from the casing. The spring pushes the lancet needle so as to launch the lancet needle. During forward movement of the press-launching mechanism, the barbs pass across the self-locking hooks or notches. In the process of retraction, the barbs are locked with the self-locking hooks or notches and cannot return to their initial states.

Description:
BACKGROUND OF THE INVENTION 
   The present invention generally relates to an automatic safe disposable blood sampling device for medical use, more particularly, to a casing self-locking type of automatic safe blood sampling device, in which a press button of which is locked by engagement thereof with the casing of the blood sampling device after a lancet needle of the blood sampling device is launched so that the blood sample device is brought into a self-locking state and can not be reused. 
   Various types of medical blood sampling device are known, there is a tendency to develop a “mini” type automatic blood sampling device which is safe and disposable once the lancet needle is launched. In order to make it disposable, this kind of blood sampling device is provided with a disposable self-locking mechanism which achieves self-locking effect immediately after a lancet needle of the blood sampling device is launched, thus causing the catch-launching mechanism failure. Therefore, the potential safety hazards involved in the previous blood sampling device are thoroughly eliminated. 
   Presently, there are two types of self-locking mechanism. The first type of self-locking mechanism employs a structure in which the lancet needle is engaged with a casing, that is, the lancet needle and the casing each are provided with a special structure, the engagement of the lancet needle with the casing achieves a self-locking effect after the lancet needle of the blood sampling device is launched. For example, the Chinese Utility Model No. CN2486104Y filed on Jul. 30, 2001 and granted to the applicant of the present application on Apr. 17, 2002 discloses an automatic safe disposable blood sampling device having a new type catch-launching mechanism, in the blood sampling device of the above Chinese Utility Model No. CN2486104Y, an elastic arm C is slantwise provided on the lancet needle and a stopping notch is provided in the casing of the blood sampling device. After the lancet needle of blood sampling device is launched, the elastic arm C is retracted together with the lancet needle so as to fall into the stopping notch to be self-locked therewith. 
   The second type of self-locking mechanism is a lancet needle self-locking structure, that is, the self-locking mechanism is completely provided on the lancet needle, and achieves a self-locking effect after the lancet needle of the blood sampling device is launched. For example, the Chinese Patent Application No. 200420025752.5 filed on Mar. 25, 2004 by the same applicant as that of the present application discloses an automatic safe disposable blood sampling device of lancet needle self-locking type. In the blood sampling device, and an elastic arm is provided on a side portion of the lancet needle. A self-locking hook is provided on an end of the elastic arm, and the elastic arm is inwardly bent upon application of an external force when the lancet needle of the blood sampling device is launched by pressing. Consequently, and the end is forced across the hook so as to be caught by the self-locking hook, thus achieving the self-locking effect. The above two types of self-locking mechanisms have disadvantageous in their structures, features and effects respectively. 
   BRIEF SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a novel casing self-locking type of automatic safe blood sampling device based on “one-off launching and not reusable” principle, in the casing self-locking type of automatic safe blood sampling device of the present invention, a self-locking mechanism is completely formed by structures on a casing. This self-locking mechanism is of the third type, that is, the casing self-locking type. 
   In order to achieve the above object, there is provided a casing self-locking type of automatic safe blood sampling device, comprising: a casing formed with a launching chamber therein, the launching chamber being provided with a lancet needle-exiting hole at a front end thereof; a lancet needle arranged inside the launching chamber; a spring; a launching mechanism composed of the spring and a catch-launching mechanism; a press-launching mechanism provided on the casing; and a self-locking mechanism composed of barbs provided on the press-launching mechanism and self-locking hooks or self-locking notches provided on the casing corresponding to the barbs, the self-locking hooks or self-locking notches being located on paths along which the barbs are advanced, respectively. 
   The related contents and variations of the above technical scheme are explained as follows: 
   1. In the above technical scheme, the self-locking mechanism has two types, i.e. the side-pressing type and the end-pressing type. 
   2. With regard to the side-pressing type of self-locking mechanism, the press-launching mechanism is embodied as press button for launching provided on a side of the blood sampling device, the press button is mounted on a side of a casing or formed by a first elastic arm extended integrally from the side of the casing, barbs are provided on the press button, and self-locking hooks or self-locking notches are provided on the casing corresponding to the barbs. 
   3. With regard to the end-pressing type of self-locking mechanism, the press-launching mechanism is embodied as a sliding sleeve provided at an end of the blood sampling device, the sliding sleeve as a part of the casing of the blood sampling device is slideably connected to another part of the casing, barbs are provided on the sliding sleeve, and self-locking hooks or self-locking notches are provided on provided on the another part of the casing corresponding to the barbs respectively. 
   The operation of the blood sampling device according to the present invention is described as follows. 
   When being pressed, the press-launching mechanism triggers the catch-launching mechanism, so that the lancet needle is disengaged from the casing, the spring pushes the lancet needle so as to launch the lancet needle. As the same time, because of movement of the press-launching mechanism, the barbs pass across the self-locking hooks or self-locking notches during the forward movement thereof. Therefore, during retraction, the barbs are locked with the self-locking hooks or self-locking notches and thereby can not return to their primed states, thereby the catch-launching mechanism is caused to be failure and can not be reused. 
   By comparison to the prior art, the blood sampling device has the following advantages. 
   1. The self-locking mechanism of the blood sampling device according to the present invention is novel, the self-locking function is achieved by changing structure of the casing, so that the blood sampling device is simple in structure and can be operated reliably. 
   2. The operation of the self-locking mechanism is performed in the following orders: the self-locking mechanism firstly enters into its self-locking state, and then enters into launching state. However, the conventional self-locking mechanism using engagement of the lancet needle with the casing is firstly launched, and then enters into its self-locking state. Therefore, the blood sampling device according to the present invention can reflect the design philosophy of one-off launching and not reusable. 
   3. In comparison to the conventional self-locking mechanism, the self-locking mechanism of the present invention is novel, simple in structure. 
   4. The blood sampling device according to the present invention is easy to use and simple to operate. 
   5. After use, the lancet needle is retracted into the casing automatically and will be not exposed to outside, thus ensuring safety of the used blood sampling device. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a structural sectional view of the blood sampling device according to the first embodiment of the present invention, showing an assembled state before use; 
       FIG. 2  is a structural sectional view of the blood sampling device according to the first embodiment of the present invention, showing that the lancet needle is pushed into a self-locked state; 
       FIG. 3  is a structural sectional view of the blood sampling device according to the first embodiment of the present invention, showing that the blood sampling device is in a state to be launched with a lancet needle cap being removed; 
       FIG. 4  is a structural sectional view of the blood sampling device according to the first embodiment of the present invention, showing that the blood sampling device is in a launching state; 
       FIG. 5  is a structural sectional view of the blood sampling device according to the first embodiment of the present invention, showing a state after use; 
       FIG. 6  is a partial sectional view of a self-locking mechanism of the blood sampling device according to the first embodiment of the present invention, showing a state before the lancet needle is locked; 
       FIG. 7  is a sectional view taken along line B-B in  FIG. 6 ; 
       FIG. 8  is a partial sectional view of a self-locking mechanism of the blood sampling device according to the first embodiment of the present invention, showing that the blood sampling device is in a state to be launched; 
       FIG. 9  is a sectional view taken along line A-A in  FIG. 8 ; and 
       FIG. 10  is a structural schematic view of the blood sampling device according to the second embodiment of the present invention. 
   

   In the above drawings, the reference numerals denote the following members respectively:  1 : case;  2 : lancet needle;  2 - 1 : first locking section;  2 - 2 : second locking section;  3 : spring;  4 : launching chamber;  5 : lancet needle-exiting hole;  6 : elongated lancet needle cap;  7 : boss;  8 : lancet needle tip;  9 : catching plate;  10 : catching groove;  11 : protruding ring;  12 : second elastic arm;  13 : first elastic arm;  13 - 1 : intermediate section of the first elastic arm;  13 - 2 : extension section of the first elastic arm;  13 - 3 : leg;  14 : blocking notch;  15 : barb;  16 : self-locking hook;  17 : sliding sleeve;  18 : bevel;  19 : elastic catching member;  20 : outer sleeve. 
   DETAILED DESCRIPTION OF THE INVENTION 
   Embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
   THE FIRST EMBODIMENT 
   As shown in  FIG. 1  to  FIG. 5 , there is illustrated a side-pressing and casing self-locking type of automatic safe disposable blood sampling device, comprising a casing  1 , a lancet needle  2 , an elongated lancet needle cap  6  and a spring  3 . 
   The casing  1  comprises an upper part and a lower part which are connected into an integral structure by using holes and pins provided on contacting surfaces thereof respectively. A launching chamber  4  is formed inside the casing  1 , and the lancet needle  2  and the spring  3  are arranged in the launching chamber  4 . The spring  3  is located behind the lancet needle  2  wherein the head of the spring  3  is caught in a catching groove  10 , and the tail of the spring  3  is caught on the catching plate  9 , thus forming an elastic sliding structure in a launching direction. A lancet needle-exiting hole  5  is provided at one end of the casing  1  in a direction consistent with the launching chamber direction. A cylindrical boss  7  is provided at the head of the lancet needle  2 , and a lancet needle tip  8  is extended centrally out of the boss  7 . Further, a protruding ring  11  is provided circumferentially on the boss  7 . An elongated lancet needle cap  6  has a rod structure and is provided with a deep hole in a front portion thereof and a tail wing at a rear end thereof. The front portion of the elongated lancet needle cap  6  passes through the lancet needle-exiting hole  5  so as to fit over the boss  7 , and the elongated lancet needle cap  6  can be prevented from retracting accidentally from the boss  7  through engagement of the protruding ring  11  with the deep hole. 
   A catch-launching mechanism and a self-locking mechanism are provided between the lancet needle  2  and a side of the casing  1  along a compression path of the spring  3 . 
   As shown  FIGS. 6 to 9 , the catch-launching mechanism comprises a second elastic arm  12  extended from a side of the casing  1 , a first elastic arm  13  extended from another side of the casing  1 , and a blocking notch  14  provided in the lancet needle  2 . The second elastic arm  12  and the blocking notch  14  are located at a bottom side of the casing  1  in  FIGS. 1 to 5 , and the second elastic arm  12  is inclined towards to the inside of the launching chamber  4 . A cantilever end of the second elastic arm  12  is engaged with the blocking notch  14  so as to form a locking structure. The first elastic arm  13  serving as a press button is located at an upper side of the casing  1  in  FIG. 1 , and an intermediate section  13 - 1  of the first elastic arm  13  serving as a pressing portion protrudes from the upper side of the casing  1  in  FIG. 1 . An extension section  13 - 2  of the first elastic arm  13  has an inversed U-shape, and the lancet needle  12  is located between two legs  13 - 3  of the inversed U-shape extension section  13 - 2  while two legs  13 - 3  extend into holes provided on the casing  1  and pass across the launching chamber  4  respectively. Distal ends of the two legs  13 - 3  contact or are close to the cantilever end of the second elastic arm  12 . 
   The self-locking mechanism comprises barbs  15  provided respectively on two outer sides of the inversed U-shape extension section  13 - 2 , and self-locking hooks  16  provided at positions corresponding to the barbs  15  on the inner wall of the casing  1 . The self-locking hooks  16  are located on paths along which the barbs  15  are advanced. In order to protect the self-locking mechanism in a state in which the lancet needle  2  of the blood sampling device is not launched, the lancet needle  2  is provided with a first locking section  2 - 1  and a second locking section  2 - 2 . Prior to being locked, the position of the second locking section  2 - 2  corresponds to that of the inversed U-shape extension section  13 - 2  as shown in  FIG. 1 , and the bottom side of the second locking section  2 - 2  has the same inclination and inclined direction as that of the second elastic arm  12 . The cross section of the second locking section  2 - 2  has substantially the same width from top to bottom, and widths of gaps formed between the two sides of the second locking section  2 - 2  and the inner walls of the casing  1  are smaller than that of the two legs  13 - 3  of the inversed U-shape extension section  13 - 2 . Therefore, at this time, the inversed U-shape extension section  13 - 2  of the first elastic arm  13  can not move downwards. As a result, the barbs  15  on the inversed U-shape extension section  13 - 2  can not engage with the self-locking hooks  16  on the casing  1  so as to lock with each other respectively, as shown in  FIG. 7 . When the lancet needle  2  is pushed towards to the rear side (right side in  FIG. 1 ) of the casing  1 , the first locking section  2 - 1  of the lancet needle  2  is moved rearwards so that the position of the first locking section  2 - 1  is brought to gradually come close to the position of the inversed U-shape extension section  13 - 2  of the first elastic arm  13 . The width of the cross-section of the first locking section  2 - 1  is decreased gradually from top to bottom, and the widths of gaps formed between two sides of the first locking section  2 - 1  and the inner walls of the casing  1  are equal to or larger than that of the two legs  13 - 3  of the inversed U-shape extension section  13 - 2  respectively. Therefore, the inversed U-shape extension section  13 - 2  can be moved downwards so that the barbs  15  can be moved downwards along with the inversed U-shape extension section  13 - 2  so as to be engaged and locked with the self-locking hooks  16  on the casing  1 . Before the cantilever end of the second elastic arm  12  is caught by the blocking notch, since the second locking section  2 - 2  has a larger width in the transverse direction of the cross-section thereof (the cross-section of the second locking section  2 - 2  has a rectangle shape in the embodiment, as shown in  FIG. 7 ), the inversed U-shape extension section  13 - 2  of the first elastic arm  13  can not pass through the gaps formed between the inversed U-shape extension section  13 - 2  and inner walls of the casing  1  even if pressing the inversed U-shape extension section  13 - 2 , thus achieving the self-locking mechanism. The lancet needle  2  is brought into a locking state by pushing the elongated lancet needle cap  6 , at this time, the first locking section  2 - 1  of the lancet needle  2  corresponds to the inversed U-shape extension section  13 - 2 , since the transverse width of the cross-section of the first locking section  2 - 1  is decreased from top to bottom (the cross-section of the first locking section  2 - 1  has a tapered shape in this embodiment, as shown in  FIG. 9 ), the widths of the gaps increase, so that two legs  13 - 3  of the inversed U-shape extension section  13 - 2  of the first elastic arm  13  can be inserted into the gaps formed between the inversed U-shape extension section  13 - 2  and inner walls of the casing  1  by pressing the inversed U-shape extension section  13 - 2 , contact with and act on the cantilever end of the second elastic arm  12  at last, thus causing the cantilever end of the second elastic arm  12  to disengage from the blocking notch  14 . 
   THE SECOND EMBODIMENT 
   As shown in  FIG. 10 , there is illustrated an end-pressing and casing self-locking type of automatic safe disposable blood sampling device, comprising a casing, a lancet needle  2 , an elongated lancet needle cap  6  and a spring  3 . The casing comprises a sliding sleeve  17  and an outer sleeve  20 , and an elastic catching member  19  is provided at a side of the lancet needle  2 . When the elongated lancet needle cap  6  is pushed, the lancet needle  2  presses the spring  3 . While the elastic catching member  19  is caught at an end of the sliding sleeve  17 , thus achieving locking. The self-locking mechanism comprises a barb  15  and a self-locking hook  16 , and the barb  15  is provided on the sliding sleeve  17  while the self-locking hook  16  is provided on the outer sleeve  20 . 
   In operation, the elongated lancet needle cap  6  is first pulled out, then the outer sleeve  20  is held by hand of a user. Thereafter, the lancet needle-exiting hole in the casing is directed at a region of a human body to be blood-sampled and the blood sampling device is pressed. At the same time, the sliding sleeve  17  is moved by an external force towards a closed end (right end in  FIG. 10 ) of the outer sleeve  20  (rightward in the  FIG. 10 ) inside an inner chamber formed inside the outer sleeve  20 . The bevel  18  forces the elastic catching member  19  to disengage from the sliding sleeve  17 , and the spring  3  pushes the lancet needle  2  along a guide groove (not shown) to launch the lancet needle  2 . Then a lancet needle tip of the lancet needle  2  is ejected out of the lancet needle-exiting hole so as to puncture the region of a human body to be blood-sampled. At the same time, since the sliding sleeve  17  is slid towards the closed end of the outer sleeve  20  inside inner chamber of the outer sleeve  20 , the barb  15  is engaged and locked with the self-locking hook  16 . Therefore, the sliding sleeve  17  can not further slide inside the inner chamber of the outer sleeve  20 , thus causing the blood sampling device to fail. 
   While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those ordinary skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt to a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims appended hereto.