Puncture device and puncture needle cartridge

Abstract

A puncture device is constituted such that a plunger ( 2 ) is provided with a lever ( 3 ) which is partially restricted in rotation, and a forward urging force is obtained by a contraction restorative force of a tension spring ( 4 ), and the tension spring ( 4 ) is again expanded with the lever ( 3 ) as a leverage when the plunger ( 2 ) further moves forward due to its inertia from a position where no urging force is not applied, and the plunger ( 2 ) is urged backward by a restorative force of the re-expansion. Further, a puncture needle cartridge is provided with a lancet body ( 203 ) having a puncture needle, and a puncture needle holder ( 201 ) in which the lancet body ( 203 ) is movably stored, and further, the lancet body ( 203 ) has an arm means ( 302 ) and the puncture needle holder ( 201 ) contains a to-be-latched means ( 303 ) that cooperates with the arm means ( 302 ). Thereby, the fabrication process is simplified, and plural times of punctures of the puncture needle is prevented, and further, the puncture speed is controlled, and moreover, the used puncture needle is discarded safely.

1 . A puncture device comprising:
 a housing having an opening at its front end, and a plunger which is held in the housing, slidably in forward and backward directions of the housing, said plunger holding a puncture needle detachably; and   a tension spring which urges the plunger in its forward and backward directions;   wherein said plunger is provided with a lever that is rotatable within a predetermined range, around a rotation shaft that is provided on the plunger;
 a front end of the tension spring is fixed to a first tension spring fixing chip that is fixed in the housing; 
   a rear end of the tension spring is latched by a second tension spring fixing part that is provided on the rotatable lever;   said second tension spring fixing part moves backward in conjunction with backward movement of the plunger, and expands the tension spring in an axial direction of the puncture device;   said tension spring urges the plunger toward the front end of the housing via the second tension spring fixing part and the lever, by a restorative force that is caused by the expansion of the tension spring in its axial direction; and   when the plunger moves toward the front end of the housing due to the urging force toward the front end, a fulcrum shaft provided on the housing contacts a peripheral edge portion of the rotatable lever, which is located between the rotation axis and the second tension spring fixing part, and the plunger further moves forward due to its inertial force even after the contact and thereby the fulcrum shaft pushes the rotatable lever backward, whereby the tension spring is again expanded via the rotatable lever and urges the plunger toward the rear end by its restorable force that occurs due to the re-expansion.   
     
     
         2 . A puncture device as defined in  claim 1  wherein
 said plunger has a first projection;   said housing has a lock plate that engages with the first projection;   urging of the plunger toward the front end of the housing by the restorative force that occurs due to expansion of the tension spring in its axial direction is restricted by that the first projection and the lock plate are engaged with each other; and   when the engagement of the first projection with the lock plate is released by moving the lock plate with an external operation, the tension spring moves the plunger toward the front end of the housing by its urging force toward the front end.   
     
     
         3 . A puncture device as defined in  claim 2  further including a puncture speed control mechanism for adjusting the restorative force of the tension spring by changing the position of the lock plate in the axial direction, thereby to control a puncture speed. 
     
     
         4 . A puncture device as defined in  claim 1  further including a puncture needle cartridge injection mechanism for injecting a puncture needle cartridge, said mechanism having an injection rod that contacts an internal end surface of the puncture needle cartridge in the housing after the puncture operation is completed, and pushes out the cartridge. 
     
     
         5 . A puncture needle cartridge which is constituted by a lancet comprising a lancet body having a puncture needle and a puncture needle protection cap for protecting the puncture needle, and a puncture needle holder which has an opening and holds the lancet body so that the lancet body is movable in the holder, wherein
 said lancet body further includes an arm means which is shaped such that one end thereof is connected to the lancet body while the other end is opened so as to be broadened toward the front end of the lancet body, and is elastically deformable outward or toward the center of the lancet body;   said puncture needle holder is a cylindrical holder which has a to-be-latched means that cooperates with the arm means, and holds the lancet body movably along its axial direction, from an initial position of the lancet body where the arm means is positioned behind the to-be-latched means or from a first position as a puncture preparation position to a second position where the puncture needle protrudes;   said lancet body is constituted such that, when it moves from the first position along the puncture direction, said arm means operates in conjunction with the to-be-latched means of the puncture needle holder and elastically deforms outward the lancet body, and the to-be-latched means contacts the contact part at said one end of the arm means and thereby movement of the to-be-latched means in the puncture direction is stopped;   when said puncture needle cartridge is inserted into the puncture device from the rear end of the lancet body, said arm means is engaged with the housing of the puncture device, and elastically deforms toward the center of the lancet body so that it does not cooperate with the to-be-latched means of the puncture needle holder, and thereby the lancet body moves from the first position to the second position to perform puncture operation; and   after the puncture is completed, when removing the puncture needle cartridge from the puncture device, the puncture needle cartridge is pulled and thereby the lancet body and the puncture needle holder move apart from each other, and the lancet body returns to the first position from the third position as a puncture end position, and when the puncture needle cartridge is further pulled, the engagement of the arm means with the housing of the puncture device is released as well as the elastic deformation of the arm means toward the center of the lancet body is released.   
     
     
         6 . A puncture needle cartridge as defined in  claim 5  wherein
 said to-be-latched means is formed of a convex part that is provided inside the puncture needle holder;   said puncture needle protection cap protects the puncture needle, and fixes the lancet body so that the lancet body does not move in the puncture needle holder when the puncture needle cartridge is inserted in the puncture device;   when the puncture needle cartridge having the puncture needle protection cap is inserted in the puncture device, said lancet body is fixed so as not to move in the puncture needle holder, and the arm means is engaged with the housing of the puncture device and thereby the arm means elastically deforms toward the center of the lancet body; and   when the puncture needle cartridge from which the puncture needle protection cap is removed is inserted in the puncture device, the lancet body and the puncture needle holder move so as to approach each other, and the arm means and the convex portion of the to-be-latched means cooperate with each other, whereby the arm means elastically deforms outward from the lancet body.   
     
     
         7 . A puncture needle cartridge as defined in  claim 5  wherein
 said lancet body has a first convex portion on its trunk portion while said puncture needle holder has, in its axial direction, a groove that fits to the first convex portion, and said groove guides the first convex portion, whereby the lancet body moves in the puncture needle holder along its axial direction.   
     
     
         8 . A puncture needle cartridge as defined in  claim 5  wherein
 said lancet body further has, on a rear end of the trunk portion, a second convex portion that operates in conjunction with the rear end surface of the puncture needle holder.   
     
     
         9 . A puncture needle cartridge as defined in  claim 8  being constituted such that the lancet is incorporated in the puncture needle holder, wherein
 said second convex portion comprises an elastically deformable material, and has a shape that inclines toward the rear end of the trunk portion of the lancet body, and   when the lancet is incorporated in the puncture needle holder, the rear end of the lancet is inserted from the front end of the puncture needle holder so that the second convex portion is elastically deformed.   
     
     
         10 . A puncture device as defined in  claim 2  further including a puncture needle cartridge injection mechanism for injecting a puncture needle cartridge, said mechanism having an injection rod that contacts an internal end surface of the puncture needle cartridge in the housing after the puncture operation is completed, and pushes out the cartridge. 
     
     
         11 . A puncture device as defined in  claim 3  further including a puncture needle cartridge injection mechanism for injecting a puncture needle cartridge, said mechanism having an injection rod that contacts an internal end surface of the puncture needle cartridge in the housing after the puncture operation is completed, and pushes out the cartridge.