Patent Publication Number: US-2021178087-A1

Title: Injection needle and injection device

Description:
TECHNICAL FIELD 
     The present invention relates to an injection needle and an injection device for performing prevention and treatment of various diseases, for example by subcutaneous or intradermal administration of an objective substance, and more particularly, the present invention relates to the injection needle and the injection device, of which puncture depth of a needle can be adjusted. 
     BACKGROUND ART 
     As an example disclosing an injection needle and an injection device, there is a Patent Document 1. A percutaneous administration device as described in Patent Document 1 is composed of a medicinal solution injection needle and a syringe. The medicinal solution injection needle comprises a medicinal solution injection needle body made of resin. The medicinal solution injection needle body has a cylindrical shape, and a hollow portion has been formed on the side of the base end thereof. Moreover, the medicinal solution injection needle body has three penetration holes formed therein, into which needles are inserted and fixed, respectively. 
     Meanwhile, the syringe is composed of a syringe body and a plunger. The top end side of the syringe body is inserted into the hollow portion of the medicinal solution injection needle body, whereby the medicinal solution injection needle is attached to the syringe. 
     Thus, when the plunger is depressed so as to discharge a medicinal solution from the inside of the syringe body, the medicinal solution enters from the hollow portion of the medicinal solution injection needle body into the inside of the needle, so as to be injected subcutaneously or intradermally from the top end of the needle. 
     Moreover, before using, the medicinal solution injection needle has been covered by a needle holder. 
     REFERENCE DOCUMENTS OF CONVENTIONAL ART 
     Patent Document(s) 
     
         
         Patent Document 1: Official Gazette, Japan Patent No. 5890430. 
       
    
     SUMMARY OF THE INVENTION 
     Problems to be Solved by Invention 
     However, the above structure of the conventional art has the following problem: 
     The subcutaneous or intradermal puncture depth of the needle will vary and is not constant. On the other hand, with regard to the percutaneous administration device as described in Patent Document 1, the protrusion length of the needle fixed in the medicinal solution injection needle body, namely the protrusion length of the needle protruding from the medicinal solution injection needle body, is invariable, and of course, the puncture depth is also invariable. Consequently, in order to cope with various puncture depths, it has been necessary to prepare several types of medicinal solution injection needles, each of which has a different protrusion length of the needle protruding from the medicinal solution injection needle body. 
     In the light of the above problem, it is an object of the present invention to provide an injection needle and an injection device, of which puncture depth of a needle can be adjusted. 
     Means to Solve the Problem 
     To achieve the objects mentioned above, according to claim  1  of the present invention, there is an injection needle provided with: a needle; a needle base holding the needle in a state of protruding toward the top end side; and an adjuster disposed to be movable along the axis direction of the needle base on the outer periphery of the needle base, wherein a protrusion length of the needle is adjusted by adjusting a position of the adjuster in the axis direction. 
     Moreover, according to the injection needle of claim  2  of the present invention, with regard to the injection needle as claimed in claim  1 , the top end of the needle is capable of being retracted in the adjuster. 
     Moreover, according to the injection needle of claim  3  of the present invention, with regard to the injection needle as claimed in claim  1  or claim  2 , the adjuster is movable in the axis direction of the needle base by a screw engagement structure. 
     Moreover, according to the injection needle of claim  4  of the present invention, with regard to the injection needle as claimed in claim  3 , a needle base is provided with a needle-base side reference position marker, and the adjuster is provided with an adjuster side reference position marker. 
     Moreover, according to the injection needle of claim  5  of the present invention, with regard to the injection needle as claimed in claim  3  or claim  4 , the moving amount of the adjuster toward the top end side is limited to a predetermined amount by a stopper mechanism. 
     Moreover, according to the injection needle of claim  6  of the present invention, with regard to the injection needle as claimed in claim  5 , the stopper mechanism is composed of a collar portion on the side of the adjuster becoming in contact with an end of a male screw portion on the side of the needle base. 
     Moreover, according to the injection needle of claim  7  of the present invention, with regard to the injection needle as claimed in claim  6 , the adjuster is provided with a longitudinally-split groove, so as to allow expansion of the diameter when attaching to the needle base. 
     Moreover, according to the injection needle of claim  8  of the present invention, with regard to the injection needle as claimed in claim  6 , the cross-section shape of the male screw portion of the needle base is in a non-circular shape, and the cross-section shape of an opening of the collar portion of the adjuster is also in a non-circular shape correspondingly, and by matching each position in the rotative direction, the male screw portion becomes capable of penetrating through the inside of the adjuster. 
     Moreover, according to the injection needle of claim  9  of the present invention, with regard to the injection needle as claimed in any one Claim among claim  1  to claim  8 , the needle is provided in a plural number. 
     Moreover, according to the injection needle of claim  10  of the present invention, with regard to the injection needle as claimed in claim  9 , a medicinal solution outlet of the needle is oriented inwardly in the radial direction of the needle base. 
     Moreover, according to the injection needle of claim  11  of the present invention, with regard to the injection needle as claimed in any one Claim among claim  1  to claim  10 , the needle base is provided with a holding projection. 
     Moreover, according to the injection needle of claim  12  of the present invention, with regard to the injection needle as claimed in any one Claim among claim  1  to claim  11 , the outer periphery of the adjuster is crowned with a cap so as to cover the needle. 
     Moreover, according to the injection needle of claim  13  of the present invention, with regard to the injection needle as claimed in claim  12 , the cap is fitted in the adjuster, so that the adjuster is capable of being rotated with the rotation of the cap. 
     Moreover, according to the injection needle of claim  14  of the present invention, with regard to the injection needle as claimed in claim  13 , the adjuster is provided with an engagement projection, and the cap is provided with an engagement opening to be engaged with the engagement projection. Moreover, according to the injection needle of claim  15  of the present invention, with regard to the injection needle as claimed in claim  12 , the cap encloses the adjuster and is fitted in the needle base in a state that the rotation is prohibited. 
     Moreover, according to the injection needle of claim  16  of the present invention, with regard to the injection needle as claimed in claim  15 , the rotation of the adjuster by the cap is not allowed in a state that the cap is fitted in the needle base, and when the state of fitting in the needle base is released by pulling the cap by a predetermined amount, the rotation of the adjuster by the cap is allowed. 
     Moreover, according to the injection needle of claim  17  of the present invention, with regard to the injection needle as claimed in claim  14 , the back surface side of the cap is provided with a structure to be fitted in the adjuster so as to be able to rotate the adjuster. 
     And moreover, according to the injection needle of claim  18  of the present invention, there is an injection device provided with: a syringe; and the injection needle as claimed in any one Claim among claim  1  to claim  17 , disposed at the top end of the syringe. 
     Effect of the Invention 
     As described above, according to claim  1  of the present invention, there is the injection needle provided with: a needle; a needle base holding the needle in a state of protruding toward the top end side; and an adjuster disposed to be movable along the axis direction of the needle base on the outer periphery of the needle base, wherein a protrusion length of the needle is adjusted by adjusting a position of the adjuster in the axis direction. Therefore, the protrusion length of the needle can be adjusted, and it is no longer necessary to prepare several types of injection needles, each of which has a different protrusion length as was the case of the conventional art. 
     Moreover, according to the injection needle of claim  2  of the present invention, with regard to the injection needle as claimed in claim  1 , the top end of the needle is capable of being retracted in the adjuster. Therefore, for example, attachment of a cap after injection is not required, and for example, it is possible to prevent accidental needle pricking caused by double-puncture (wrong puncture after completion of puncture) by users such as physicians or nurses. 
     Moreover, according to the injection needle of claim  3  of the present invention, with regard to the injection needle as claimed in claim  1  or claim  2 , the adjuster is movable in the axis direction of the needle base by a screw engagement structure. Therefore, the puncture depth of the needle can be adjusted by easy operation. 
     Moreover, according to the injection needle of claim  4  of the present invention, with regard to the injection needle as claimed in claim  3 , a needle base is provided with a needle-base side reference position marker, and the adjuster is provided with an adjuster side reference position marker. Therefore, the number of rotations of the adjuster can be known accurately according to the positional relation in the rotative direction between the needle-base side reference position marker and the adjuster side reference position marker, whereby the puncture depth of the needle can be adjusted easily and accurately. 
     Moreover, according to the injection needle of claim  5  of the present invention, with regard to the injection needle as claimed in claim  3  or Claim  4 , the moving amount of the adjuster toward the top end side is limited to a predetermined amount by a stopper mechanism. Therefore, it is possible to prevent the drop-off toward the top end side of the adjuster. 
     Moreover, according to the injection needle of claim  6  of the present invention, with regard to the injection needle as claimed in claim  5 , the stopper mechanism is composed of a collar portion on the side of the adjuster becoming in contact with an end of a male screw portion on the side of the needle base. Therefore, the stopper mechanism in a simple structure can be composed. 
     Moreover, according to the injection needle of claim  7  of the present invention, with regard to the injection needle as claimed in claim  6 , the adjuster is provided with a longitudinally-split groove, so as to allow expansion of the diameter when attaching to the needle base. Therefore, even where the collar portion, which is a part of the stopper mechanism, is provided, it is possible to attach the adjuster to the needle base, and the assembling thereof can be accomplished easily. 
     Moreover, according to the injection needle of claim  8  of the present invention, with regard to the injection needle as claimed in claim  6 , the cross-section shape of the male screw portion of the needle base is in a non-circular shape, and the cross-section shape of an opening of the collar portion of the adjuster is also in a non-circular shape correspondingly, and by matching each position in the rotative direction, the male screw portion becomes capable of penetrating through the inside of the adjuster. Therefore, also with this structure, even where the collar portion, which is a part of the stopper mechanism, is provided, it is possible to attach the adjuster to the needle base, and the assembling thereof can be accomplished easily. 
     Moreover, according to the injection needle of claim  9  of the present invention, with regard to the injection needle as claimed in any one Claim among claim  1  to claim  8 , the needle is provided in a plural number. Therefore, it is possible to perform injection more efficiently. 
     Moreover, according to the injection needle of claim  10  of the present invention, with regard to the injection needle as claimed in claim  9 , a medicinal solution outlet of the needle is oriented inwardly in the radial direction of the needle base. Therefore, the injected medicinal solution will diffuse widely, and simultaneously, will remain in a shallow portion of the skin. 
     Moreover, according to the injection needle of claim  11  of the present invention, with regard to the injection needle as claimed in any one Claim among claim  1  to claim  10 , the needle base is provided with a holding projection. Therefore, for example, when the injection needle is attached to the top end of the syringe, such an attachment work can be performed by holding the holding projection, and accordingly, any unintended rotation of the adjuster can be prevented. 
     Moreover, according to the injection needle of claim  12  of the present invention, with regard to the injection needle as claimed in any one Claim among claim  1  to claim  11 , the outer periphery of the adjuster is crowned with a cap so as to cover the needle. Therefore, it is possible to prevent the accidental needle pricking. 
     Moreover, according to the injection needle of claim  13  of the present invention, with regard to the injection needle as claimed in claim  12 , the cap is fitted in the adjuster, so that the adjuster is capable of being rotated with the rotation of the cap. Therefore, it is possible to rotate the adjuster in a state of being covered by the cap so as to adjust the protrusion amount of the needle. Consequently, it is also possible to prevent the accidental needle pricking. 
     Moreover, according to the injection needle of claim  14  of the present invention, with regard to the injection needle as claimed in claim  13 , the adjuster is provided with an engagement projection, and the cap is provided with an engagement opening to be engaged with the engagement projection. Therefore, with the engagement of the engagement opening with the engagement projection, it is possible to rotate the adjuster in a state of being covered by the cap so as to adjust the protrusion amount of the needle. Consequently, it is also possible to prevent the accidental needle pricking. 
     Moreover, according to the injection needle of claim  15  of the present invention, with regard to the injection needle as claimed in claim  12 , the cap encloses the adjuster and is fitted in the needle base in a state that the rotation is prohibited. Therefore, for example, when the injection needle is attached to the top end of the syringe, such an attachment work can be performed by holding the cap, and accordingly, any unintended rotation of the adjuster can be prevented. 
     Moreover, according to the injection needle of claim  16  of the present invention, with regard to the injection needle as claimed in claim  15 , the rotation of the adjuster by the cap is not allowed in a state that the cap is fitted in the needle base, and when the state of fitting in the needle base is released by pulling the cap by a predetermined amount, the rotation of the adjuster by the cap is allowed. Therefore, with just the pulling of the cap by a predetermined amount, it is possible to adjust the protrusion amount of the needle by rotating the cap integrally with the adjuster. Consequently, it is also possible to prevent the accidental needle pricking. 
     Moreover, according to the injection needle of claim  17  of the present invention, with regard to the injection needle as claimed in claim  14 , the back surface side of the cap is provided with a structure to be fitted in the adjuster so as to be able to rotate the adjuster. Therefore, by using this structure, it is possible to adjust the protrusion amount of the needle by rotating the adjuster in a state of being covered by the cap. 
     And moreover, according to the injection needle of claim  18  of the present invention, there is the injection device provided with: a syringe; and the injection needle as claimed in any one Claim among claim  1  to claim  17 , disposed at the top end of the syringe. Therefore, it is possible to provide the injection device in which the puncture depth of the needle can be adjusted. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a plan view of an injection device according to a first embodiment of the present invention. 
         FIG. 2  is a perspective view of an injection needle as seen from the top end side according to the first embodiment of the present invention. 
         FIG. 3  is a perspective view of the injection needle as seen from the base end side according to the first embodiment of the present invention. 
         FIG. 4  is a sectional view as seen by IV-IV of  FIG. 2  according to the first embodiment of the present invention. 
         FIG. 5  is a perspective view of needles and a needle base of the injection needle as seen from the top end side according to the first embodiment of the present invention. 
         FIG. 6  is a perspective view of the needles and the needle base of the injection needle as seen from the base end side according to the first embodiment of the present invention. 
         FIG. 7  is a perspective view of an adjuster of the injection needle as seen from the top end side according to the first embodiment of the present invention. 
         FIG. 8  is a perspective view of the adjuster of the injection needle as seen from the top end side according to the first embodiment of the present invention. 
         FIG. 9  is a longitudinal sectional view of the injection needle in a state that the protrusion length of the needle is decreased by moving the adjuster forward according to the first embodiment of the present invention. 
         FIG. 10  is a longitudinal sectional view of the injection needle in a state that the needles are retracted in the adjuster by further moving the adjuster forward according to the first embodiment of the present invention. 
         FIG. 11  is a perspective view of the injection needle in a state that the needles are covered by attaching a cap to the top end side according to the first embodiment of the present invention. 
         FIG. 12  is a sectional view as seen by XII-XII of  FIG. 11  according to the first embodiment of the present invention. 
         FIG. 13  is a longitudinal sectional view of an injection needle in a state that an adjuster moves rearward to the base end according to a second embodiment of the present invention. 
         FIG. 14  is a longitudinal sectional view of the injection needle in a state that the adjuster moves forward to the top end according to the second embodiment of the present invention. 
         FIG. 15  is a perspective view of the injection needle as seen from the top end side according to the second embodiment of the present invention. 
         FIG. 16  is a plan view of an injection device according to a third embodiment of the present invention. 
         FIG. 17  is a perspective view of an injection needle as seen from the top end side, in a state that an adjuster moves rearward to the base end according to the third embodiment of the present invention. 
         FIG. 18  is a perspective view of the injection needle as seen from the base end side, in a state that the adjuster moves rearward to the base end according to the third embodiment of the present invention. 
         FIG. 19  is a sectional view as seen by XIX-XIX of  FIG. 17  according to the third embodiment of the present invention. 
         FIG. 20  is a perspective view of the injection needle as seen from the top end side, in a state that the adjuster moves forward to the top end according to the third embodiment of the present invention. 
         FIG. 21  is a perspective view of the injection needle as seen from the base end side, in a state that the adjuster moves forward to the top end according to the third embodiment of the present invention. 
         FIG. 22  is a sectional view as seen by XXII-XXII of  FIG. 20  according to the third embodiment of the present invention. 
         FIG. 23  is a perspective view of the adjuster of the injection needle as seen from the top end side according to the third embodiment of the present invention. 
         FIG. 24  is a perspective view of the adjuster of the injection needle as seen from the base end side according to the third embodiment of the present invention. 
         FIG. 25  is a perspective view of a needle base of the injection needle as seen from the top end side according to the third embodiment of the present invention. 
         FIG. 26  is a perspective view of the needle base of the injection needle as seen from the base end side according to the third embodiment of the present invention. 
         FIG. 27   FIGS. 27( a ), 27( b )  and  27 (C) are views according to the third embodiment of the present invention, in which,  FIG. 27 ( a )  is a perspective view of a cap as seen from the top end side,  FIG. 27 ( b )  is a perspective view of the cap as seen from the base end side, and  FIG. 27 ( c )  is a longitudinal sectional view of the injection needle with the cap. 
         FIG. 28   FIGS. 28( a ), 28( b ) and 28( c )  are views according to the third embodiment of the present invention, in which,  FIG. 28 ( a )  is perspective view of the injection needle with the cap as seen from the top end side,  FIG. 28 ( b )  is a perspective view of the injection needle with the cap as seen from the base end side, and  FIG. 28 ( c )  is a longitudinal sectional view of the injection needle with the cap. 
         FIG. 29   FIGS. 29( a ), 29( b ) and 29( c )  are views according to a fourth embodiment of the present invention, in which,  FIG. 29 ( a )  is a perspective view of a cap,  FIG. 29 ( b )  is a perspective view showing a state that a needle-base-side fitting part of the cap is fitted in the needle base. and  FIG. 29 ( c )  is a perspective view showing a state that the cap is turned reversely so that an adjuster-side fitting part of the cap is fitted in the adjuster. 
     
    
    
     MODE(S) FOR CARRYING OUT THE INVENTION 
     Now, a first embodiment of the present invention will be explained with reference to  FIG. 1  to  FIG. 12 . As illustrated in  FIG. 1 , an injection device  1  according to the first embodiment is composed of a syringe  3 , and an injection needle  5  attached to be detachable to the top end of the syringe  3 . 
     The syringe  3  is composed of an injection cylinder  7  in a hollow shape, of which top end side (on the left of  FIG. 1 ) and base end side (on the right of  FIG. 1 ) are opening, and a plunger  9  inserted into the injection cylinder  7  from the base end side (on the right of  FIG. 1 ). The diameter at the top end side (on the left of  FIG. 1 ) of the injection cylinder  7  is reduced, serving as an injection needle connecting part  11 . The plunger  9  is disposed to be movable in the forward and rearward directions (in the left and right directions of  FIG. 1 ) in the inside of the injection cylinder  7 . The injection cylinder  7  is filled with an unillustrated medicinal solution therein, and by moving the plunger  9  to the top end side (to the left of  FIG. 1 ), the medicinal solution is discharged from the top end of the injection cylinder  7 . 
     As illustrated in  FIG. 1  to  FIG. 4 , the injection needle  5  is composed of a needle base  21 , and four needles  23 ,  23 ,  23 ,  23 , each of which being attached protrusively to the top end side (on the left of  FIG. 4 ) of the needle base  21 , and an adjuster  25 . 
     As illustrated in  FIG. 4 , a syringe connecting recess  27  is formed on the base end side of the needle base  21 . The injection needle connecting part  11  of the syringe  3  is inserted into the syringe connecting recess  27 . Moreover, as illustrated in  FIG. 2 ,  FIG. 4  and  FIG. 5 , four needle fixing penetration holes  29 ,  29 ,  29 ,  29 , each of which has openings both on the side of the syringe connecting recess  27  and on the top end side (on the left of  FIG. 4 ), are formed in the needle base  21 . Each of the needles  23 ,  23 ,  23 ,  23  is penetrating through and disposed in the needle fixing penetration holes  29 ,  29 ,  29 ,  29 , respectively, and is fixed by adhesives  31 ,  31 ,  31 ,  31 , each of which being injected into the needle fixing penetration holes  29 ,  29 ,  29 ,  29 , respectively. Moreover, a medicinal solution outlet  23   a  of each of the needles  23 ,  23 ,  23 ,  23  is cut obliquely, and is oriented inwardly in the radial direction of the needle base  21 . 
     Moreover, as illustrated in  FIG. 4 ,  FIG. 5  and  FIG. 6 , a male screw portion  33  is formed on the top end side (on the left of  FIG. 4 ) of the needle base  21 . Moreover, as illustrated in  FIG. 5  and  FIG. 6 , the top and bottom ends of the male screw portion  33 , as shown in  FIG. 5 , have been cut off due to molding reasons. These cut-off portions are shown by reference signs  34 ,  34  in the drawings. Moreover, as illustrated in  FIG. 4 ,  FIG. 5  and  FIG. 6 , there are projections  35 ,  35 , protrusively formed, respectively, at positions opposing to each other at the angle of 180 degrees. Moreover, at the position somewhat closer to the rear (to the right of  FIG. 4 ) than the center of the axis direction (the left/right direction of  FIG. 4 ) of the needle base  21 , there are base-end side stoppers  37 ,  37 , protrusively formed, respectively, at positions opposing to each other at the angle of 180 degrees. 
     As illustrated in  FIG. 4 ,  FIG. 7  and  FIG. 8 , the adjuster  25  is a member in a cylindrical shape, and a female thread portion  39  is formed in the inner peripheral surface thereof, to become in screw engagement with the male screw portion  33  of the needle base  21 . The adjuster  25  is attached to the needle base  21  to be movable along the axis direction, by the screw engagement structure between the female thread portion  39  and the male screw portion  33  of the needle base  21 . 
     With the rotative operation of the adjuster  25  so as to move along the axis direction (the left/right direction of  FIG. 4 ) of the needle base  21 , as illustrated in  FIG. 4 ,  FIG. 9  and  FIG. 10 , the protrusion length of the needles  23 ,  23 ,  23 ,  23  (as shown by reference sign L in  FIG. 4 ), respectively, and eventually the puncture depth of the needles  23 ,  23 ,  23 ,  23 , respectively, is adjusted. When the adjuster  25  is positioned at the right end of  FIG. 4  so that the base end thereof becomes in contact with the base-end side stoppers  37 ,  37 , the protrusion length (L) of the needles  23 ,  23 ,  23 ,  23 , respectively, is in the maximum length (L max ). 
     For reference, in the present embodiment, the maximum protrusion length (L max ) of the needle  23 , as shown in  FIG. 4 , is set to 4 mm, as an example. 
     From the above state, when the adjuster  25  is rotated counterclockwise as seen from the side facing to the direct front of the adjuster  25  at the left end in  FIG. 4 , so as to move to the left of  FIG. 4 , the needles  23 ,  23 ,  23 ,  23 , respectively, are retracted gradually in the adjuster  25 , and the protrusion length (L) of each of the needles  23 ,  23 ,  23 ,  23  becomes shorter gradually. 
     For reference, in the case of actual use, for the purpose of effective puncturing, the protrusion length (L) of each of the needles  23 ,  23 ,  23 ,  23  is set, for example, to be at least about 1 mm. 
     Moreover, after completion of puncture, as illustrated in  FIG. 10 , the adjuster  25  is moved to the top end side, until each of the needles  23 ,  23 ,  23 ,  23  is completely retracted in the inside of the adjuster  25 . Accordingly, it is possible to prevent accidental needle pricking caused by double-puncture (wrong puncture after completion of puncture) by users such as physicians or nurses. 
     For reference, in  FIG. 10 , the top end of each of the needles  23 ,  23 ,  23 ,  23  is in a state of being withdrawn from the top end of the adjuster  25 , for example, at least about 1 to 3 mm inwardly. 
     Moreover, as illustrated in  FIG. 11 , there is a needle-base side reference position marker  40   a  protrusively formed on the needle base  21 , and there is also an adjuster side reference position marker  40   b  protrusively formed on the adjuster  25 . The position in the rotative direction of the needle-base side reference position marker  40   a  and the position in the rotative direction of the adjuster side reference position marker  40   b  are set to match with each other, when the adjuster  25  is at the position closest to the base end side (a state as shown in  FIG. 4 ). 
     For example, when the adjuster  25  moves from an initial state as described above, toward the top end side, by referring to the needle-base side reference position marker  40   a  and also to the adjuster side reference position marker  40   b , it is possible to visually recognize how many times the adjuster  25  was rotated. By referring to such a number of rotations and to the leading amount of the screw engagement structure between the male screw portion  33  and the female thread portion  39 , it is possible to set the protrusion amount of each of the needles  23 ,  23 ,  23 ,  23  at an arbitrary value. This is to mean that, the maximum protrusion length (L max ) of each of the needles  23 ,  23 ,  23 ,  23  in the initial state of  FIG. 4  has been determined (in the present embodiment, 4 mm), and meanwhile, with reference to the number of rotations of the adjuster  25 , the moving amount of the adjuster  25  toward the top end side has also been determined. Thus, by deducting the moving amount (as shown by reference sign L′ in  FIG. 9 ) from the maximum protrusion length in the initial state (L max ), it is possible to set the protrusion length (L), and eventually the puncture depth, of each of the needles  23 ,  23 ,  23 ,  23 . 
     Moreover, as illustrated in  FIG. 11  and  FIG. 12 , before using, a cap  41  is crowned to be detachable on the top end side (on the left of  FIG. 12 ) of the adjuster  25  of the injection needle  5 . There are engagement openings  43 ,  43 , formed in the cap  41 , respectively, at positions opposing to each other at the angle of 180 degrees, and there are also engagement projections  45 ,  45 , protrusively formed, respectively, at positions opposing to each other at the angle of 180 degrees, on the outer periphery of the adjuster  25 . By engagement of the engagement openings  43 ,  43  of the cap  41  with the engagement projections  45 ,  45  of the adjuster  25 , respectively, the cap  41  is fixed in the adjuster  25 . 
     For reference, as illustrated in  FIG. 12 , even in the initial state in which each of the needles  23 ,  23 ,  23 ,  23  is protruding toward the top end side (the left side of  FIG. 12 ) of the adjuster  25 , the top end of each of the needles  23 ,  23 ,  23 ,  23  will not become in contact with the inner surface of the cap  41 . 
     Next, the function of the present invention according to the first embodiment will be explained. 
     First, before using, the injection needle  5  is in a state as shown in  FIG. 11  and  FIG. 12 . 
     Next, the medicinal solution is filled in the injection cylinder  7  of the syringe  3 . 
     Next, the injection needle  5  is attached to the injection cylinder  7  of the syringe  3 . 
     Next, the cap  41  is detached, so as to be in a usable state as illustrated in  FIG. 1  to  FIG. 4 . In such a state, the protrusion length (L) of each of the needles  23 ,  23 ,  23 ,  23  is at the maximum protrusion length (L max ). 
     Next, the adjuster  25  is rotated counterclockwise as seen from the side facing to the direct front of the adjuster  25  at the left end in FIG.  1  to  FIG. 4 , so as to move the adjuster  25  to the left of  FIG. 1  to  FIG. 4  at an appropriate amount, whereby the protrusion length (L) of each of the needles  23 ,  23 ,  23 ,  23 , and eventually the puncture depth of each of the needles  23 ,  23 ,  23 ,  23 , is adjusted arbitrarily. 
     Next, the side of the needles  23 ,  23 ,  23 ,  23  of the injection device  1  is oriented to the skin (not shown) as an object to be punctured, and the needles  23 ,  23 ,  23 ,  23  are punctured vertically against the skin. At that time, the top end surface of the adjuster  25  (the surface on the left of  FIG. 1  to  FIG. 4 ) becomes in contact with the skin, and the puncture is performed at a predetermined puncture depth. 
     Next, the plunger  9  of the syringe  3  is depressed to apply force toward the top end side (the left of  FIG. 1  to  FIG. 4 ), whereby the medicinal solution is injected. 
     After completion of injection, the needles  23 ,  23 ,  23 ,  23  are removed from the skin. Thereafter, the adjuster  25  is rotated counterclockwise as seen from the side facing to the direct front of the adjuster  25  at the left end in  FIG. 1  to  FIG. 4 , so as to move the adjuster  25  to the top end side (to the left of  FIG. 1  to  FIG. 4 ), and as illustrated in  FIG. 10 , the top end side of each of the needles  23 ,  23 ,  23 ,  23  is retracted in the adjuster  25 . Thus, the double-puncture (wrong puncture after completion of puncture) is prevented. Further, the top end is covered by crowning of the cap  41 , and the whole body of the injection device  1  is disposed as the waste in such a state. Otherwise, only the injection needle  5  is disposed as the waste, by detaching the injection needle  5  from the syringe  3 . 
     Next, the effect of the present invention according to the first embodiment will be explained. 
     First, it is possible to arbitrarily adjust the protrusion length (L), and eventually the puncture depth of each of the needles  23 ,  23 ,  23 ,  23 . This is because of the structure in which the adjuster  25  is attached to be movable to the outer periphery of the needle base  21 , so that the position in the axis direction can be adjusted arbitrarily. 
     Moreover, since the protrusion length (L), and eventually the puncture depth of each of the needles  23 ,  23 ,  23 ,  23  can be adjusted arbitrarily, it is not necessary to prepare several types of injection needles  5 , each of which protrusion length is different from each other, and accordingly, in addition to the reduction of cost, it is also possible to accomplish the easy management of the injection needles  5 . 
     Moreover, as illustrated in  FIG. 10 , after completion of puncture, the top end of each of the needles  23 ,  23 ,  23 ,  23  can be retracted in the adjuster  25 , and accordingly, even without the need of attachment of the cap  41 , it is possible to prevent accidental needle pricking caused by double-puncture (wrong puncture after completion of puncture) by users such as physicians or nurses. 
     Moreover, with the attachment of the cap  41 , the safety can be further improved. 
     Moreover, before using, the cap  41  is crowned on the top end side of the adjuster  25 , and accordingly, for example, it is possible to prevent injury of a user before using. 
     Moreover, since the adjuster  25  is attached to be movable on the outer periphery of the needle base  21  by the screw engagement structure, it is possible to move the adjuster  25  easily, and accordingly, the adjustment of the protrusion length (L), and eventually the puncture depth of each of the needles  23 ,  23 ,  23 ,  23 , can be facilitated. 
     Moreover, the needle-base side reference position marker  40   a  is formed on the needle base  21 , and the adjuster side reference position marker  40   b  is also formed on the adjuster  25 , and accordingly, it is possible to visually recognize the number of rotations of the adjuster  25 , whereby the protrusion length (L), and eventually the puncture depth of each of the needles  23 ,  23 ,  23 ,  23 , can be adjusted accurately. 
     And moreover, since the medicinal solution outlet  23   a  of each of the needles  23 ,  23 ,  23 ,  23  is oriented inwardly in the radial direction of the needle base  21 , the injected medicinal solution will diffuse widely, and simultaneously, will remain in a shallow portion of the skin. 
     Next, a second embodiment of the present invention will be explained with reference to  FIG. 13  to  FIG. 15 . In the first embodiment, the moving amount of the adjuster  25  toward the top end side is not limited specifically. However, in the second embodiment, this amount is limited to a predetermined value. 
     First, as illustrated in  FIG. 13 , an adjuster-side stopper  51  is provided on the base end side (on the left end side of  FIG. 13 ) of the adjuster  25 . The adjuster-side stopper  51  is in a ring shape, and is provided in a shape of collar. Meanwhile, the base end side (the right end side of  FIG. 13 ) of the female thread portion  33 , attached to the needle base  21 , serves as a needle-base-side stopper  53 . Thus, with the movement of the adjuster  25  to the top end side (to the left of  FIG. 13 ), and as illustrated in  FIG. 14 , when the adjuster-side stopper  51  becomes in contact with the needle-base-side stopper  53 , the further movement of the adjuster  25  toward the top end side (the left of  FIG. 14 ) is prohibited. Accordingly, the needles  23 ,  23 ,  23 ,  23  are retracted securely in the adjuster  25 , and also the drop-off of the adjuster  25  from the needle base  21  is prevented. 
     Moreover, since the adjuster-side stopper  51  is provided to the adjuster  25 , there is a concern about the attachment of the adjuster  25  to the needle base  21 . To cope with this concern, as illustrated in  FIG. 15 , a longitudinally-split groove  55  is provided in the adjuster  25 . When the adjuster  25  is attached to the needle base  21 , the attachment is performed by expanding the diameter of the adjuster  25 , to some width within the range of the longitudinally-split groove  55 . 
     The other structure is substantially the same as that of the first embodiment, and the same reference signs will be allotted to the same elements in the drawings, and the explain thereof will be omitted. 
     According to the above structure, it is possible to achieve substantially the same effect as that of the first embodiment explained above. 
     Moreover, since the moving amount of the adjuster  25  to the top end side is limited to a predetermined value, it is possible to prevent any unintended drop-off of the adjuster  25  from the needle base  21 . 
     Moreover, when a user moves forward the adjuster  25  until the adjuster-side stopper  51  becomes in contact with the needle-base-side stopper  53 , the user is able to confirm that the needles  23 ,  23 ,  23 ,  23  are retracted in the adjuster  25 , at the position capable of preventing the double-puncture (wrong puncture after completion of puncture). 
     Next, a third embodiment of the present invention will be explained with reference to  FIG. 16  to  FIG. 28( c ) . As illustrated in  FIG. 16  to  FIG. 22 , an injection needle  105  according to the third embodiment is composed of a needle base  121 , and four needles  123 ,  123 ,  123 ,  123 , each of which being attached protrusively to the top end side (on the left of  FIG. 16 ) of the needle base  121 , and an adjuster  125 . 
     As illustrated in  FIG. 19 , a syringe connecting recess  127  is formed on the base end side of the needle base  121 . The injection needle connecting part  11  of the syringe  3  is inserted into the syringe connecting recess  127 . Moreover, as illustrated in  FIG. 17  and  FIG. 19 , four needle fixing penetration holes  129 ,  129 ,  129 ,  129 , each of which has openings both on the side of the syringe connecting recess  127  and on the top end side (on the left of  FIG. 25 ), are formed in the needle base  121 . 
     Each of the needles  123 ,  123 ,  123 ,  123  is penetrating through and disposed in the needle fixing penetration holes  129 ,  129 ,  129 ,  129 , respectively, and is fixed by adhesives  131 ,  131 ,  131 ,  131 , each of which being injected into the needle fixing penetration holes  129 ,  129 ,  129 ,  129 , respectively. Moreover, as illustrated in  FIG. 17  and  FIG. 19 , a medicinal solution outlet  123   a  of each of the needles  123 ,  123 ,  123 ,  123  is cut obliquely, and is oriented inwardly in the radial direction of the needle base  121 . 
     Moreover, as illustrated in  FIG. 19 , a male screw portion  133  is formed on the top end side (on the left of  FIG. 19 ) of the needle base  121 . Moreover, as illustrated in  FIG. 25  and  FIG. 26 , the both transverse side portions of the male screw portion  133  have been cut off, serving as cut-off portions  134 ,  134 . Moreover, as illustrated in  FIG. 19 ,  FIG. 20  and  FIG. 21 , there are projections  135 ,  135 , protrusively formed, respectively, at positions opposing to each other at the angle of 180 degrees. Moreover, at the position somewhat closer to the rear (to the right of  FIG. 19 ) than the center of the axis direction (the left/right direction of  FIG. 19 ) of the needle base  121 , there is a substantially-diamond-shaped holding projection  137 , formed protrusively in a shape of collar. The holding projection  137  also has a function to serve as a stopper to limit the rearward movement of the adjuster  125  to the base end side, to a predetermined amount. Moreover, as illustrated in  FIG. 20 ,  FIG. 21 ,  FIG. 25  and  FIG. 26 , the needle base  121  is provided with four recesses  139 ,  139 ,  139 ,  139 , each of which being disposed orthogonally, for the purpose of prevention of sink (depression due to shrinking) during molding work. 
     As illustrated in  FIG. 17 ,  FIG. 18  and  FIG. 19 , the adjuster  125  is composed of a collar portion  141 , and a cylindrical portion  143  fastened to the collar portion  141 . There are openings  145 ,  145 , formed in the cylindrical surface of the collar portion  141 , respectively, at positions opposing to each other at the angle of 180 degrees. Moreover, there are claws  147 ,  147 , protrusively disposed at positions opposing to each other at the angle of 180 degrees, respectively, at the end part of the cylindrical portion  143  on the side of the collar portion  141 . When the cylindrical portion  143  is inserted into the inner diametrical portion of the collar portion  141 , the claws  147 ,  147  become engaged with the openings  145 ,  145 , respectively, whereby the cylindrical portion  143  is integrated into the collar portion  141 . 
     Moreover, as illustrated in  FIG. 24 , an opening  142  of the collar portion  141  is in a circular shape, of which two transverse side portions have been cut away, so as to form flat surfaces  144 ,  144 , respectively. This shape corresponds to the shape of the male screw portion  133  of the needle base  121 . When the male screw portion  133  of the needle base  121  penetrates through the inside of the adjuster  125 , the positions of the cut-off portions  134 ,  134  of the male screw portion  133  of the needle base  121 , and the positions of the flat surfaces  144 ,  144  of the opening  142  of the collar portion  141  of the adjuster  125 , shall be matched to each other. Moreover, after completion of attachment, when the adjuster  125  is rotated so as to move to the top end side, the collar portion  141  becomes in contact with the end of the male screw portion  133 , whereby the stopper function is exhibited, and further movement is prohibited. When the position of the cut-off portions  134 ,  134  of the male screw portion  133  of the needle base  121 , and the positions of the flat surfaces  144 ,  144  of the opening  142  of the collar portion  141  of the adjuster  125 , are matched to each other, the pulling off thereof can be performed, but the movement with the rotation cannot be performed. 
     There is a female thread portion  149  formed in the inner peripheral surface of the cylindrical surface  143 , to become in screw engagement with the male screw portion  133  of the needle base  121 . The adjuster  125  is attached to the needle base  121  to be movable along the axis direction, by the screw engagement structure between the female thread portion  149  and the male screw portion  133  of the needle base  121 . 
     As illustrated in  FIG. 16  to  FIG. 18 ,  FIG. 20  and  FIG. 21 , there are rib-shaped guide projections  151 ,  151 ,  151 ,  151 , respectively, protrusively provided at four orthogonal positions on the outer peripheral surface of the cylindrical portion  143 . Moreover, there are engagement projections  153 ,  153 ,  153 ,  153 , protrusively provided at the end part of the guide projections  151 ,  151 ,  151 ,  151 , respectively, on the side of the collar portion  141 . 
     Meanwhile, as illustrated in  FIGS. 27( a ) to 27( c )  and  FIGS. 28( a ) to 28( c ) , there is a cap  155 , and guide projections  157 ,  157 ,  157 ,  157  are provided, respectively, on the inner peripheral surface of the cap  155 , to be engaged with the guide projections  151 ,  151 ,  151 ,  151 , respectively, in the rotative direction. This is to mean that, when the cap  155  is crowned on the adjuster  125 , the guide projections  157 ,  157 ,  157 ,  157 , on the side of the cap  155 , are positioned, in a respective interval of the guide projections  151 ,  151 ,  151 ,  151 , on the side of the adjuster  125 . Moreover, each of the guide projections  157 ,  157 ,  157 ,  157 , is provided in a form of V-shape elongating in the longitudinal direction. Consequently, the guide function is exhibited effectively, and the crowning of the cap  155  on the adjuster  125  can be performed smoothly. Moreover, there are engagement openings  159 ,  159 ,  159 ,  159 , respectively provided in the intervals of the guide projections  157 ,  157 ,  157 ,  157 . Each of the engagement openings  159 ,  159 ,  159 ,  159 , is engaged with the respective engagement projections  153 ,  153 ,  153 ,  153 . 
       FIGS. 28( a ), 28( b ) and 28( c )  show state, in which the cap  155  is crowned on the injection needle  105 . 
     The other structure is substantially the same as that of the first embodiment, and the same reference signs will be allotted to the same elements in the drawings, and the explain thereof will be omitted. 
     Accordingly, it is possible to achieve substantially the same effect as that of the first embodiment described above. 
     Moreover, since the holding projection  137  is provided, for example, when the injection needle  105  is attached to the top of the syringe  3 , the holding projection  137  is held by the left hand, and at the same time, the syringe  3  is held by the right hand, whereby the injection needle connecting part  11  can be inserted into the syringe connecting recess  127  so as to be attached thereto, and consequently, it is not necessary to hold the cap  155  or the adjuster  125 , and there is no risk of unintended rotation of the adjuster  125  to fasten tightly. 
     Next, a fourth embodiment of the present invention will be explained with reference to  FIGS. 29( a ), 29( b ) and 29( c ) . In the case of the first to the third embodiments, the cap is fitted in the adjuster of the injection needle in a state that the rotation thereof is prohibited. On the other hand, in the case of the fourth embodiment, the cap is fitted in the needle base side in a state that the rotation thereof is prohibited. The details will be explained hereinafter. 
     As illustrated in  FIG. 29 ( a ) , a cap  201  is provided with a cap body  203 , and a needle-base-side fitting portion  205  is provided on one end side of the cap body  203 , and furthermore, an adjuster-side fitting portion  207  is provided on the other end side of the cap body  203 . There are engagement portions  209 ,  209 , provided respectively on the needle-base-side fitting portion  205 , at positions opposing to each other at the angle of 180 degrees. As illustrated in  FIG. 29 ( b ) , the engagement portions  209 ,  209  become engaged with engagement portions  211 ,  211 , respectively, of the holding projection  137  of the needle base  121 . 
     There are four engagement opening  213 ,  213 ,  213 ,  213 , respectively formed at orthogonal positions to each other, in the needle-base-side fitting portion as described above. The engagement openings  213 ,  213 ,  213 ,  213  become engaged with four engagement projections (the engagement projections, having substantially the same structure as that of the engagement projections  153  of the third embodiment), respectively, provided on the adjuster  125 . 
     There are also four engagement opening  215 ,  215 ,  215 ,  215 , respectively formed at orthogonal positions to each other, in the adjuster-side fitting portion  207 . The engagement openings  215 ,  215 ,  215 ,  215  also become engaged with the four engagement projections as described above, respectively, provided on the adjuster  125 . 
     The other structure is substantially the same as that of the third embodiment, and the same reference signs will be allotted to the same elements in the drawings, and the explain thereof will be omitted. 
     According to the above structure, the normal state is shown in  FIG. 29 ( b ) , in which, the needle-base-side fitting portion  205  of the cap  201 , enclosing the adjuster  125  of the injection needle, has been fitted in a part of the needle base  121 , and also in which, the engagement portions  209 ,  209  of the needle-base-side fitting portion  205  are engaged with the engagement portions  211 ,  211 , respectively, of the holding projection  137  of the needle base  121 . In this state, when the injection needle  105  is attached to the top of the syringe, the cap  201  is held by the left hand, and at the same time, the syringe is held by the right hand, whereby the injection needle connecting part of the syringe is inserted into the syringe connecting recess  127 . At that time, since the cap  201  is fixed in the holding projection  137  and eventually in the needle base  121 , there is no risk of unintended rotation of the cap  201 , and consequently, there is also no risk of unintended rotation of the adjuster  125 . 
     Next, the adjustment of the protrusion length of the needle will be explained. For this purpose, as illustrated in  FIG. 29 ( c ) , the adjuster-side fitting portion  207  of the cap  201  becomes engaged with the adjuster  125 . In such a state, by holding the cap  201 , the adjuster  125  is rotated, so as to adjust the protrusion length of the needle. Consequently, it is possible to prevent accidental needle pricking at the time of adjustment of the protrusion length of the needle. 
     The present invention is not limited to the first to the fourth embodiment as described above. 
     First, in the first to the fourth embodiments, the explanations have been made for the structure of four needles as an example. However, it is of course possible to be composed of other structures, such as one needle, or two, three, five or more needles. 
     Moreover, in the first to the fourth embodiments, the adjuster is movable by the screw engagement structure. However, the present invention is not limited to such a structure, and it is also possible, for example, to be movable by an appropriate fit-in-each-other structure. 
     Moreover, in the second embodiment, it is possible to use the longitudinally-split groove also as the adjuster side reference position marker. 
     Moreover, in the second embodiment, with the stopper mechanism, the needle is securely retracted by the adjuster, and the drop-off of the adjuster is prevented. However, it is also possible to utilize in the different structure, for the purpose of limiting the protrusion length of the needle within a predetermined range. As a possible structure, for example, in the initial state before using, the protrusion length of the needle may be set to 4 mm, and when the forward movement of the adjuster is prohibited by the stopper mechanism, the protrusion length of the needle may be set to 1 mm. 
     Moreover, in the first to the fourth embodiments, the adjuster is rotated counterclockwise as seen from the side facing to the direct front of the adjuster, so as to shorten the protrusion length of the needle. However, it is also possible to rotate in the reverse direction. 
     Moreover, in the first to the fourth embodiments, the adjuster is in the hollow cylindrical shape. However, the present invention is not limited to such a structure, and it is possible, for example, to be in a square shape, or any other shape. For example, in the case of square shape, if one rotation varies the length by 1 mm, then, the rotation at the angle of 90 degrees may vary the protrusion length by ¼ mm. 
     Moreover, in the first to the fourth embodiments, the adjuster is rotated in a state that the cap has been detached, so as to adjust the protrusion length of the needle. However, it is also possible to make such an adjustment in a state that the cap remains in the crowned state, whereby the accidental needle pricking can also be prevented. 
     Moreover, it is also possible to provide scales of the protrusion length of the needle for reference purpose, on the adjuster or the needle base, by molding or printing. 
     Moreover, in the first to the fourth embodiments, the medicinal solution outlet of the needle is oriented inwardly in the radial direction, but the direction is not limited to these embodiments. 
     Moreover, in the fourth embodiment, the needle-base-side fitting portion and the adjuster-side fitting portion are provided in the opposite directions, respectively. However, it is also possible to provide the needle-base-side fitting portion only. In this structure, it is also possible that, by pulling the cap at a predetermined amount toward the top end side, the needle-base-side fitting portion is released from the fitting state in the needle base, and then, is fitted in the adjuster. Thus, in such a state, the protrusion length of the needle can also be adjusted by rotating the adjuster integrally with the cap. 
     For example, in the fourth embodiment, in the state as illustrated in  FIG. 29 ( b ) , the engagement openings  213  is engaged with the engagement projection on the side of the adjuster. However, with regard to the engagement opening  213 , by increasing the length in the axis direction thereof, even when the cap is pulled toward the top end side at a predetermined amount so as to release the fitting of the needle-base-side fitting portion out of the needle base, the engagement opening  213  may maintain the engagement state with the engagement projection on the side of the adjuster, and thus, in such a state, the protrusion length of the needle can be adjusted by rotating the adjuster integrally with the cap. 
     Moreover, as an another example, in the state as illustrated in  FIG. 29 ( b )  according to the fourth embodiment, it is also possible to provide a structure, in which, the engagement opening  213  passes by the engagement projection on the side of the adjuster without engagement therewith, and when the cap is pulled toward the top end side at a predetermined amount so as to release the fitting of the needle-base-side fitting portion out of the needle base, the engagement opening  213  becomes engaged with the engagement projection on the side of the adjuster. Thus, also in such a state, the protrusion length of the needle can be adjusted by rotating the adjuster integrally with the cap. 
     Furthermore, the structures shown in the drawings are merely for example purposes only. 
     INDUSTRIAL APPLICABILITY 
     The present invention relates to the injection needle and the injection device for performing prevention and treatment of various diseases, for example by subcutaneous or intradermal administration of an objective substance, and more particularly, the present invention relates to the injection needle and the injection device, of which puncture depth of a needle can be adjusted. The present invention is suitable, for example, for the injection needle and the injection device used for treatment in the field of cosmetic dermatology. 
     EXPLANATION OF REFERENCE NUMERALS AND SIGNS 
     
         
         
           
               1  Injection Device 
               3  Syringe 
               5  Injection Needle 
               21  Needle Base 
               23  Needle 
               23   a  Medicinal Solution Outlet 
               25  Adjuster 
               33  Male Screw Portion 
               39  Female Thread Portion 
               40   a  Needle-base Side Reference Position Marker 
               40   b  Adjuster Side Reference Position Marker 
               41  Cap 
               51  Adjuster-side Stopper 
               53  Needle-base-side Stopper 
               55  Longitudinally-split Groove