Patent Description:
As an example disclosing an injection needle and an injection device, there is a Patent Document <NUM>. A percutaneous administration device as described in Patent Document <NUM> 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. Further relevant prior art is described in <CIT>, <CIT> and <CIT>.

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 <NUM>, 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.

The present invention provides an injection needle having the features defined in claim <NUM>.

As described above, according to Claim <NUM> , 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, 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, 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, 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 <NUM> , with regard to the injection needle as claimed in Claim <NUM>, 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 <NUM> , with regard to the injection needle as claimed in Claim <NUM>, 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 <NUM> , with regard to the injection needle as claimed in Claim <NUM>, 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 <NUM> , with regard to the injection needle as claimed in Claim <NUM>, 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 <NUM> , with regard to the injection needle as claimed in any one Claim among Claim <NUM> to Claim <NUM>, 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 <NUM>, with regard to the injection needle as claimed in Claim <NUM>, 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 <NUM>, with regard to the injection needle as claimed in any one Claim among Claim <NUM> to Claim <NUM>, 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 <NUM> , with regard to the injection needle as claimed in any one Claim among Claim <NUM> to Claim <NUM>, 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 <NUM>, with regard to the injection needle as claimed in Claim <NUM>, 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 <NUM>, with regard to the injection needle as claimed in Claim <NUM>, 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 <NUM>, with regard to the injection needle as claimed in Claim <NUM>, 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.

Now, a first arrangement will be explained with reference to <FIG>. As illustrated in <FIG>, an injection device <NUM> according to the first arrangement is composed of a syringe <NUM>, and an injection needle <NUM> attached to be detachable to the top end of the syringe <NUM>.

The syringe <NUM> is composed of an injection cylinder <NUM> in a hollow shape, of which top end side (on the left of <FIG>) and base end side (on the right of <FIG>) are opening, and a plunger <NUM> inserted into the injection cylinder <NUM> from the base end side (on the right of <FIG>). The diameter at the top end side (on the left of <FIG>) of the injection cylinder <NUM> is reduced, serving as an injection needle connecting part <NUM>. The plunger <NUM> is disposed to be movable in the forward and rearward directions (in the left and right directions of <FIG>) in the inside of the injection cylinder <NUM>. The injection cylinder <NUM> is filled with an unillustrated medicinal solution therein, and by moving the plunger <NUM> to the top end side (to the left of <FIG>), the medicinal solution is discharged from the top end of the injection cylinder <NUM>.

As illustrated in <FIG>, the injection needle <NUM> is composed of a needle base <NUM>, and four needles <NUM>, <NUM>, <NUM>, <NUM>, each of which being attached protrusively to the top end side (on the left of <FIG>) of the needle base <NUM>, and an adjuster <NUM>.

As illustrated in <FIG>, a syringe connecting recess <NUM> is formed on the base end side of the needle base <NUM>. The injection needle connecting part <NUM> of the syringe <NUM> is inserted into the syringe connecting recess <NUM>. Moreover, as illustrated in <FIG>, <FIG> and <FIG>, four needle fixing penetration holes <NUM>, <NUM>, <NUM>, <NUM>, each of which has openings both on the side of the syringe connecting recess <NUM> and on the top end side (on the left of <FIG>), are formed in the needle base <NUM>. Each of the needles <NUM>, <NUM>, <NUM>, <NUM> is penetrating through and disposed in the needle fixing penetration holes <NUM>, <NUM>, <NUM>, <NUM>, respectively, and is fixed by adhesives <NUM>, <NUM>, <NUM>, <NUM>, each of which being injected into the needle fixing penetration holes <NUM>, <NUM>, <NUM>, <NUM>, respectively. Moreover, a medicinal solution outlet 23a of each of the needles <NUM>, <NUM>, <NUM>, <NUM> is cut obliquely, and is oriented inwardly in the radial direction of the needle base <NUM>.

Moreover, as illustrated in <FIG>, <FIG> and <FIG>, a male screw portion <NUM> is formed on the top end side (on the left of <FIG>) of the needle base <NUM>. Moreover, as illustrated in <FIG> and <FIG>, the top and bottom ends of the male screw portion <NUM>, as shown in <FIG>, have been cut off due to molding reasons. These cut-off portions are shown by reference signs <NUM>, <NUM> in the drawings. Moreover, as illustrated in <FIG>, <FIG> and <FIG>, there are projections <NUM>, <NUM>, protrusively formed, respectively, at positions opposing to each other at the angle of <NUM> degrees. Moreover, at the position somewhat closer to the rear (to the right of <FIG>) than the center of the axis direction (the left/right direction of <FIG>) of the needle base <NUM>, there are base-end side stoppers <NUM>, <NUM>, protrusively formed, respectively, at positions opposing to each other at the angle of <NUM> degrees.

As illustrated in <FIG>, <FIG>, the adjuster <NUM> is a member in a cylindrical shape, and a female thread portion <NUM> is formed in the inner peripheral surface thereof, to become in screw engagement with the male screw portion <NUM> of the needle base <NUM>. The adjuster <NUM> is attached to the needle base <NUM> to be movable along the axis direction, by the screw engagement structure between the female thread portion <NUM> and the male screw portion <NUM> of the needle base <NUM>.

With the rotative operation of the adjuster <NUM> so as to move along the axis direction (the left/right direction of <FIG>) of the needle base <NUM>, as illustrated in <FIG>, <FIG> and <FIG>, the protrusion length of the needles <NUM>, <NUM>, <NUM>, <NUM> (as shown by reference sign L in <FIG>), respectively, and eventually the puncture depth of the needles <NUM>, <NUM>, <NUM>, <NUM>, respectively, is adjusted. When the adjuster <NUM> is positioned at the right end of <FIG> so that the base end thereof becomes in contact with the base-end side stoppers <NUM>, <NUM>, the protrusion length (L) of the needles <NUM>, <NUM>, <NUM>, <NUM>, respectively, is in the maximum length (Lmax).

For reference, in the present arrangement, the maximum protrusion length (Lmax) of the needle <NUM>, as shown in <FIG>, is set to <NUM>, as an example.

From the above state, when the adjuster <NUM> is rotated counterclockwise as seen from the side facing to the direct front of the adjuster <NUM> at the left end in <FIG>, so as to move to the left of <FIG>, the needles <NUM>, <NUM>, <NUM>, <NUM>, respectively, are retracted gradually in the adjuster <NUM>, and the protrusion length (L) of each of the needles <NUM>, <NUM>, <NUM>, <NUM> 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 <NUM>, <NUM>, <NUM>, <NUM> is set, for example, to be at least about <NUM>.

Moreover, after completion of puncture, as illustrated in <FIG>, the adjuster <NUM> is moved to the top end side, until each of the needles <NUM>, <NUM>, <NUM>, <NUM> is completely retracted in the inside of the adjuster <NUM>. 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>, the top end of each of the needles <NUM>, <NUM>, <NUM>, <NUM> is in a state of being withdrawn from the top end of the adjuster <NUM>, for example, at least about <NUM> to <NUM> inwardly.

Moreover, as illustrated in <FIG>, there is a needle-base side reference position marker 40a protrusively formed on the needle base <NUM>, and there is also an adjuster side reference position marker 40b protrusively formed on the adjuster <NUM>. The position in the rotative direction of the needle-base side reference position marker 40a and the position in the rotative direction of the adjuster side reference position marker 40b are set to match with each other, when the adjuster <NUM> is at the position closest to the base end side (a state as shown in <FIG>).

For example, when the adjuster <NUM> moves from an initial state as described above, toward the top end side, by referring to the needle-base side reference position marker 40a and also to the adjuster side reference position marker 40b, it is possible to visually recognize how many times the adjuster <NUM> 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 <NUM> and the female thread portion <NUM>, it is possible to set the protrusion amount of each of the needles <NUM>, <NUM>, <NUM>, <NUM> at an arbitrary value. This is to mean that, the maximum protrusion length (Lmax) of each of the needles <NUM>, <NUM>, <NUM>, <NUM> in the initial state of <FIG> has been determined (in the present arrangement, <NUM>), and meanwhile, with reference to the number of rotations of the adjuster <NUM>, the moving amount of the adjuster <NUM> toward the top end side has also been determined. Thus, by deducting the moving amount (as shown by reference sign L' in <FIG>) from the maximum protrusion length in the initial state (Lmax), it is possible to set the protrusion length (L), and eventually the puncture depth, of each of the needles <NUM>, <NUM>, <NUM>, <NUM>.

Moreover, as illustrated in <FIG> and <FIG>, before using, a cap <NUM> is crowned to be detachable on the top end side (on the left of <FIG>) of the adjuster <NUM> of the injection needle <NUM>. There are engagement openings <NUM>, <NUM>, formed in the cap <NUM>, respectively, at positions opposing to each other at the angle of <NUM> degrees, and there are also engagement projections <NUM>, <NUM>, protrusively formed, respectively, at positions opposing to each other at the angle of <NUM> degrees, on the outer periphery of the adjuster <NUM>. By engagement of the engagement openings <NUM>, <NUM> of the cap <NUM> with the engagement projections <NUM>, <NUM> of the adjuster <NUM>, respectively, the cap <NUM> is fixed in the adjuster <NUM>.

For reference, as illustrated in <FIG>, even in the initial state in which each of the needles <NUM>, <NUM>, <NUM>, <NUM> is protruding toward the top end side (the left side of <FIG>) of the adjuster <NUM>, the top end of each of the needles <NUM>, <NUM>, <NUM>, <NUM> will not become in contact with the inner surface of the cap <NUM>.

Next, the function according to the first arrangement will be explained.

First, before using, the injection needle <NUM> is in a state as shown in <FIG> and <FIG>.

Next, the medicinal solution is filled in the injection cylinder <NUM> of the syringe <NUM>.

Next, the injection needle <NUM> is attached to the injection cylinder <NUM> of the syringe <NUM>.

Next, the cap <NUM> is detached, so as to be in a usable state as illustrated in <FIG>. In such a state, the protrusion length (L) of each of the needles <NUM>, <NUM>, <NUM>, <NUM> is at the maximum protrusion length (Lmax).

Next, the adjuster <NUM> is rotated counterclockwise as seen from the side facing to the direct front of the adjuster <NUM> at the left end in <FIG>, so as to move the adjuster <NUM> to the left of <FIG> at an appropriate amount, whereby the protrusion length (L) of each of the needles <NUM>, <NUM>, <NUM>, <NUM>, and eventually the puncture depth of each of the needles <NUM>, <NUM>, <NUM>, <NUM>, is adjusted arbitrarily.

Next, the side of the needles <NUM>, <NUM>, <NUM>, <NUM> of the injection device <NUM> is oriented to the skin (not shown) as an object to be punctured, and the needles <NUM>, <NUM>, <NUM>, <NUM> are punctured vertically against the skin. At that time, the top end surface of the adjuster <NUM> (the surface on the left of <FIG>) becomes in contact with the skin, and the puncture is performed at a predetermined puncture depth.

Next, the plunger <NUM> of the syringe <NUM> is depressed to apply force toward the top end side (the left of <FIG>), whereby the medicinal solution is injected.

After completion of injection, the needles <NUM>, <NUM>, <NUM>, <NUM> are removed from the skin. Thereafter, the adjuster <NUM> is rotated counterclockwise as seen from the side facing to the direct front of the adjuster <NUM> at the left end in <FIG>, so as to move the adjuster <NUM> to the top end side (to the left of <FIG>), and as illustrated in <FIG>, the top end side of each of the needles <NUM>, <NUM>, <NUM>, <NUM> is retracted in the adjuster <NUM>. Thus, the double-puncture (wrong puncture after completion of puncture) is prevented. Further, the top end is covered by crowning of the cap <NUM>, and the whole body of the injection device <NUM> is disposed as the waste in such a state. Otherwise, only the injection needle <NUM> is disposed as the waste, by detaching the injection needle <NUM> from the syringe <NUM>.

Next, the effect according to the first arrangement will be explained.

First, it is possible to arbitrarily adjust the protrusion length (L), and eventually the puncture depth of each of the needles <NUM>, <NUM>, <NUM>, <NUM>. This is because of the structure in which the adjuster <NUM> is attached to be movable to the outer periphery of the needle base <NUM>, 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 <NUM>, <NUM>, <NUM>, <NUM> can be adjusted arbitrarily, it is not necessary to prepare several types of injection needles <NUM>, 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 <NUM>.

Moreover, as illustrated in <FIG>, after completion of puncture, the top end of each of the needles <NUM>, <NUM>, <NUM>, <NUM> can be retracted in the adjuster <NUM>, and accordingly, even without the need of attachment of the cap <NUM>, 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 <NUM>, the safety can be further improved.

Moreover, before using, the cap <NUM> is crowned on the top end side of the adjuster <NUM>, and accordingly, for example, it is possible to prevent injury of a user before using.

Moreover, since the adjuster <NUM> is attached to be movable on the outer periphery of the needle base <NUM> by the screw engagement structure, it is possible to move the adjuster <NUM> easily, and accordingly, the adjustment of the protrusion length (L), and eventually the puncture depth of each of the needles <NUM>, <NUM>, <NUM>, <NUM>, can be facilitated.

Moreover, the needle-base side reference position marker 40a is formed on the needle base <NUM>, and the adjuster side reference position marker 40b is also formed on the adjuster <NUM>, and accordingly, it is possible to visually recognize the number of rotations of the adjuster <NUM>, whereby the protrusion length (L), and eventually the puncture depth of each of the needles <NUM>, <NUM>, <NUM>, <NUM>, can be adjusted accurately.

And moreover, since the medicinal solution outlet 23a of each of the needles <NUM>, <NUM>, <NUM>, <NUM> is oriented inwardly in the radial direction of the needle base <NUM>, the injected medicinal solution will diffuse widely, and simultaneously, will remain in a shallow portion of the skin.

Next, a second arrangement will be explained with reference to <FIG>. In the first arrangement, the moving amount of the adjuster <NUM> toward the top end side is not limited specifically. However, in the second arrangement, this amount is limited to a predetermined value.

First, as illustrated in <FIG>, an adjuster-side stopper <NUM> is provided on the base end side (on the left end side of <FIG>) of the adjuster <NUM>. The adjuster-side stopper <NUM> is in a ring shape, and is provided in a shape of collar. Meanwhile, the base end side (the right end side of <FIG>) of the female thread portion <NUM>, attached to the needle base <NUM>, serves as a needle-base-side stopper <NUM>. Thus, with the movement of the adjuster <NUM> to the top end side (to the left of <FIG>), and as illustrated in <FIG>, when the adjuster-side stopper <NUM> becomes in contact with the needle-base-side stopper <NUM>, the further movement of the adjuster <NUM> toward the top end side (the left of <FIG>) is prohibited. Accordingly, the needles <NUM>, <NUM>, <NUM>, <NUM> are retracted securely in the adjuster <NUM>, and also the drop-off of the adjuster <NUM> from the needle base <NUM> is prevented.

Moreover, since the adjuster-side stopper <NUM> is provided to the adjuster <NUM>, there is a concern about the attachment of the adjuster <NUM> to the needle base <NUM>. To cope with this concern, as illustrated in <FIG>, a longitudinally-split groove <NUM> is provided in the adjuster <NUM>. When the adjuster <NUM> is attached to the needle base <NUM>, the attachment is performed by expanding the diameter of the adjuster <NUM>, to some width within the range of the longitudinally-split groove <NUM>.

The other structure is substantially the same as that of the first arrangement, 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 arrangement explained above.

Moreover, since the moving amount of the adjuster <NUM> to the top end side is limited to a predetermined value, it is possible to prevent any unintended drop-off of the adjuster <NUM> from the needle base <NUM>.

Moreover, when a user moves forward the adjuster <NUM> until the adjuster-side stopper <NUM> becomes in contact with the needle-base-side stopper <NUM>, the user is able to confirm that the needles <NUM>, <NUM>, <NUM>, <NUM> are retracted in the adjuster <NUM>, at the position capable of preventing the double-puncture (wrong puncture after completion of puncture).

Next, a third arrangement will be explained with reference to <FIG>. As illustrated in <FIG>, an injection needle <NUM> according to the third arrangement is composed of a needle base <NUM>, and four needles <NUM>, <NUM>, <NUM>, <NUM>, each of which being attached protrusively to the top end side (on the left of <FIG> of the needle base <NUM>, and an adjuster <NUM>.

As illustrated in <FIG>, a syringe connecting recess <NUM> is formed on the base end side of the needle base <NUM>. The injection needle connecting part <NUM> of the syringe <NUM> is inserted into the syringe connecting recess <NUM>. Moreover, as illustrated in <FIG> and <FIG>, four needle fixing penetration holes <NUM>, <NUM>, <NUM>, <NUM>, each of which has openings both on the side of the syringe connecting recess <NUM> and on the top end side (on the left of <FIG>), are formed in the needle base <NUM>.

Each of the needles <NUM>, <NUM>, <NUM>, <NUM> is penetrating through and disposed in the needle fixing penetration holes <NUM>, <NUM>, <NUM>, <NUM>, respectively, and is fixed by adhesives <NUM>, <NUM>, <NUM>, <NUM>, each of which being injected into the needle fixing penetration holes <NUM>, <NUM>, <NUM>, <NUM>, respectively. Moreover, as illustrated in <FIG> and <FIG>, a medicinal solution outlet 123a of each of the needles <NUM>, <NUM>, <NUM>, <NUM> is cut obliquely, and is oriented inwardly in the radial direction of the needle base <NUM>.

Moreover, as illustrated in <FIG>, a male screw portion <NUM> is formed on the top end side (on the left of <FIG>) of the needle base <NUM>. Moreover, as illustrated in <FIG>, the both transverse side portions of the male screw portion <NUM> have been cut off, serving as cut-off portions <NUM>, <NUM>. Moreover, as illustrated in <FIG>, <FIG>, there are projections <NUM>, <NUM>, protrusively formed, respectively, at positions opposing to each other at the angle of <NUM> degrees. Moreover, at the position somewhat closer to the rear (to the right of <FIG>) than the center of the axis direction (the left/right direction of <FIG>) of the needle base <NUM>, there is a substantially-diamond-shaped holding projection <NUM>, formed protrusively in a shape of collar. The holding projection <NUM> also has a function to serve as a stopper to limit the rearward movement of the adjuster <NUM> to the base end side, to a predetermined amount. Moreover, as illustrated in <FIG>, <FIG>, the needle base <NUM> is provided with four recesses <NUM>, <NUM>, <NUM>, <NUM>, each of which being disposed orthogonally, for the purpose of prevention of sink (depression due to shrinking) during molding work.

As illustrated in <FIG> and <FIG>, the adjuster <NUM> is composed of a collar portion <NUM>, and a cylindrical portion <NUM> fastened to the collar portion <NUM>. There are openings <NUM>, <NUM>, formed in the cylindrical surface of the collar portion <NUM>, respectively, at positions opposing to each other at the angle of <NUM> degrees. Moreover, there are claws <NUM>, <NUM>, protrusively disposed at positions opposing to each other at the angle of <NUM> degrees, respectively, at the end part of the cylindrical portion <NUM> on the side of the collar portion <NUM>. When the cylindrical portion <NUM> is inserted into the inner diametrical portion of the collar portion <NUM>, the claws <NUM>, <NUM> become engaged with the openings <NUM>, <NUM>, respectively, whereby the cylindrical portion <NUM> is integrated into the collar portion <NUM>.

Moreover, as illustrated in <FIG>, an opening <NUM> of the collar portion <NUM> is in a circular shape, of which two transverse side portions have been cut away, so as to form flat surfaces <NUM>, <NUM>, respectively. This shape corresponds to the shape of the male screw portion <NUM> of the needle base <NUM>. When the male screw portion <NUM> of the needle base <NUM> penetrates through the inside of the adjuster <NUM>, the positions of the cut-off portions <NUM>, <NUM> of the male screw portion <NUM> of the needle base <NUM>, and the positions of the flat surfaces <NUM>, <NUM> of the opening <NUM> of the collar portion <NUM> of the adjuster <NUM>, shall be matched to each other. Moreover, after completion of attachment, when the adjuster <NUM> is rotated so as to move to the top end side, the collar portion <NUM> becomes in contact with the end of the male screw portion <NUM>, whereby the stopper function is exhibited, and further movement is prohibited. When the position of the cut-off portions <NUM>, <NUM> of the male screw portion <NUM> of the needle base <NUM>, and the positions of the flat surfaces <NUM>, <NUM> of the opening <NUM> of the collar portion <NUM> of the adjuster <NUM>, 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 <NUM> formed in the inner peripheral surface of the cylindrical surface <NUM>, to become in screw engagement with the male screw portion <NUM> of the needle base <NUM>. The adjuster <NUM> is attached to the needle base <NUM> to be movable along the axis direction, by the screw engagement structure between the female thread portion <NUM> and the male screw portion <NUM> of the needle base <NUM>.

As illustrated in <FIG>, <FIG>, there are rib-shaped guide projections <NUM><NUM>, <NUM>, <NUM>, respectively, protrusively provided at four orthogonal positions on the outer peripheral surface of the cylindrical portion <NUM>. Moreover, there are engagement projections <NUM>, <NUM>, <NUM>, <NUM>, protrusively provided at the end part of the guide projections <NUM>, <NUM>, <NUM>, <NUM>, respectively, on the side of the collar portion <NUM>.

Meanwhile, as illustrated in <FIG> and <FIG>, there is a cap <NUM>, and guide projections <NUM>, <NUM>, <NUM>, <NUM> are provided, respectively, on the inner peripheral surface of the cap <NUM>, to be engaged with the guide projections <NUM>, <NUM>, <NUM>, <NUM>, respectively, in the rotative direction. This is to mean that, when the cap <NUM> is crowned on the adjuster <NUM>, the guide projections <NUM>, <NUM>, <NUM>, <NUM>, on the side of the cap <NUM>, are positioned, in a respective interval of the guide projections <NUM>, <NUM>, <NUM>, <NUM>, on the side of the adjuster <NUM>. Moreover, each of the guide projections <NUM>, <NUM>, <NUM>, <NUM>, 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 <NUM> on the adjuster <NUM> can be performed smoothly. Moreover, there are engagement openings <NUM>, <NUM>, <NUM>, <NUM>, respectively provided in the intervals of the guide projections <NUM>, <NUM>, <NUM>, <NUM>. Each of the engagement openings <NUM>, <NUM>, <NUM>, <NUM>, is engaged with the respective engagement projections <NUM>, <NUM>, <NUM>, <NUM>.

<FIG> shows a state, in which the cap <NUM> is crowned on the injection needle <NUM>.

Accordingly, it is possible to achieve substantially the same effect as that of the first arrangement described above.

Moreover, since the holding projection <NUM> is provided, for example, when the injection needle <NUM> is attached to the top of the syringe <NUM>, the holding projection <NUM> is held by the left hand, and at the same time, the syringe <NUM> is held by the right hand, whereby the injection needle connecting part <NUM> can be inserted into the syringe connecting recess <NUM> so as to be attached thereto, and consequently, it is not necessary to hold the cap <NUM> or the adjuster <NUM>, and there is no risk of unintended rotation of the adjuster <NUM> to fasten tightly.

Next, a fourth arrangement will be explained with reference to <FIG>. In the case of the first to the third arrangements, 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 arrangement, 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>, a cap <NUM> is provided with a cap body <NUM>, and a needle-base-side fitting portion <NUM> is provided on one end side of the cap body <NUM>, and furthermore, an adjuster-side fitting portion <NUM> is provided on the other end side of the cap body <NUM>. There are engagement portions <NUM>, <NUM>, provided respectively on the needle-base-side fitting portion <NUM>, at positions opposing to each other at the angle of <NUM> degrees. As illustrated in <FIG>, the engagement portions <NUM>, <NUM> become engaged with engagement portions <NUM>, <NUM>, respectively, of the holding projection <NUM> of the needle base <NUM>.

There are four engagement opening <NUM>, <NUM>, <NUM>, <NUM>, respectively formed at orthogonal positions to each other, in the needle-base-side fitting portion as described above. The engagement openings <NUM>, <NUM>, <NUM>, <NUM> become engaged with four engagement projections (the engagement projections, having substantially the same structure as that of the engagement projections <NUM> of the third arrangement), respectively, provided on the adjuster <NUM>.

There are also four engagement opening <NUM>, <NUM>, <NUM>, <NUM>, respectively formed at orthogonal positions to each other, in the adjuster-side fitting portion <NUM>. The engagement openings <NUM>, <NUM>, <NUM>, <NUM> also become engaged with the four engagement projections as described above, respectively, provided on the adjuster <NUM>.

The other structure is substantially the same as that of the third arrangement, 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>, in which, the needle-base-side fitting portion <NUM> of the cap <NUM>, enclosing the adjuster <NUM> of the injection needle, has been fitted in a part of the needle base <NUM>, and also in which, the engagement portions <NUM>, <NUM> of the needle-base-side fitting portion <NUM> are engaged with the engagement portions <NUM>, <NUM>, respectively, of the holding projection <NUM> of the needle base <NUM>. In this state, when the injection needle <NUM> is attached to the top of the syringe, the cap <NUM> 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 <NUM>. At that time, since the cap <NUM> is fixed in the holding projection <NUM> and eventually in the needle base <NUM>, there is no risk of unintended rotation of the cap <NUM>, and consequently, there is also no risk of unintended rotation of the adjuster <NUM>.

Next, the adjustment of the protrusion length of the needle will be explained. For this purpose, as illustrated in <FIG>, the adjuster-side fitting portion <NUM> of the cap <NUM> becomes engaged with the adjuster <NUM>. In such a state, by holding the cap <NUM>, the adjuster <NUM> 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 arrangement as described above.

First, in the first to the fourth arrangements, 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 arrangements, 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 arrangement, it is possible to use the longitudinally-split groove also as the adjuster side reference position marker.

Moreover, in the second arrangement, 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 <NUM>, and when the forward movement of the adjuster is prohibited by the stopper mechanism, the protrusion length of the needle may be set to <NUM>.

Moreover, in the first to the fourth arrangements, 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 arrangements, 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 <NUM>, then, the rotation at the angle of <NUM> degrees may vary the protrusion length by <NUM>/<NUM>.

Moreover, in the first to the fourth arrangements, 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 arrangements, the medicinal solution outlet of the needle is oriented inwardly in the radial direction, but the direction is not limited to these arrangements.

Moreover, in the fourth arrangement, 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 arrangement, in the state as illustrated in <FIG>, the engagement openings <NUM> is engaged with the engagement projection on the side of the adjuster. However, with regard to the engagement opening <NUM>, 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 <NUM> 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> according to the fourth arrangement, it is also possible to provide a structure, in which, the engagement opening <NUM> 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 <NUM> 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.

Claim 1:
An injection needle provided with:
a needle (<NUM>, <NUM>);
a needle base (<NUM>) holding the needle (<NUM>, <NUM>) in a state of protruding toward the top end side; and an adjuster (<NUM>, <NUM>) disposed to be movable along the axis direction of the needle base (<NUM>) on the outer periphery of the needle base (<NUM>), wherein a protrusion length of the needle (<NUM>, <NUM>) is adjusted by adjusting a position of the adjuster (<NUM>, <NUM>) in the axis direction;
the adjuster (<NUM>, <NUM>) is movable in the axis direction of the needle base (<NUM>) by a screw engagement structure;
characterised in that
the moving amount of the adjuster (<NUM>, <NUM>) toward the top end side is limited to a predetermined amount by a stopper mechanism (<NUM>, <NUM>);
the stopper mechanism (<NUM>, <NUM>) is composed of a collar portion (<NUM>) on the side of the adjuster (<NUM>, <NUM>) becoming in contact with an end of a male screw portion (<NUM>) on the side of the needle base (<NUM>).