JP2013056009A - Luer lock adapter of syringe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent an injection from leaking by avoiding idling a luer lock adapter when a hypodermic needle is fixed to a barrel.SOLUTION: A cylindrical engagement portion 23 is provided in the rear end of the luer lock adapter 2 and three axial slits 23a are formed in the engagement portion. Furthermore, the diameter of an inside circumference 23b located at the front side of the axial slits 23a is made equal to or larger than the diameter of the outside circumference of the barrel 1, and the diameter of the inside circumference in the rear end is made smaller than the diameter of the outside circumference of the barrel. Since the cylindrical engagement portion 23 is permitted to expand by the axial slits 23a, no accurate engagement dimension is required between both, and the luer lock adapter 2 can be surely prevented from idling at the time when the hypodermic needle 3 is fixed to the barrel 1.

Description

  The present invention relates to a luer lock adapter for a syringe for fixing an injection needle to the tip of an outer cylinder.

  Conventionally, many means for fixing an injection needle to the tip of an outer cylinder of a syringe have been proposed. One of them is the following means (see Patent Document 1). This Patent Document 1 relates to another invention by the inventor of the present application, and means for fixing the injection needle to the tip of the outer cylinder of the syringe is not necessarily detailed. Therefore, this will be described in detail with reference to FIGS.

  That is, as shown in FIG. 6, a luer 211 formed by reducing the diameter of the outer cylinder is integrally formed at the tip of the glass outer cylinder 201, and the outer periphery 211a of the luer faces the tip. Tapered. A circumferential groove 211b is formed on the outer periphery of the rear end portion of the luer 211.

  The injection needle 203 includes a cone-shaped needle base 232 made of a synthetic resin and a needle 231 inserted at the tip of the needle base. At the rear end of the outer periphery of the needle base 232, an outer flange 232a formed in the shape of a thread of an external thread is provided. Further, the inner periphery 232 b of the needle base 232 is shaped like a cone closely contacting the tapered outer periphery 211 a of the luer 211. That is, the injection needle 203 inserts and attaches the cone-shaped inner periphery 232b of the needle base 232 to the tapered outer periphery 211a of the luer 211 so that they are brought into close contact with each other. Therefore, the structure prevents the drug from leaking to the outside.

  However, simply inserting the needle base 232 of the injection needle 203 into the outer periphery 211a of the luer 211 will easily come off. Therefore, both are fixed by the luer lock adapter 202 so that the needle base 232 of the injection needle 203 does not fall out of the luer 211. That is, the luer lock adapter 202 is a cylindrical member made of synthetic resin, and has an internal thread portion 221 formed at the inner periphery of the tip portion thereof, and a locking portion 222 provided at the rear end portion thereof. is there.

  FIG. 7 shows a front view of the luer lock adapter 202 viewed from the front end side. As shown in FIG. 7, the latching portion 222 provided at the rear end portion of the luer lock adapter 202 has an inner flange 222a projecting inward, and a circular hole is formed at the center of the inner flange. A locking hole 222b is opened. The inner peripheral diameter of the locking hole 222b is slightly smaller than the groove bottom diameter of the circumferential groove 211b formed at the rear end of the outer periphery 211a of the lure 211. The inner flange 222a is provided with six slits 222c extending radially from the inner periphery of the locking hole 222b in the circumferential direction. That is, the locking hole 222b is formed by the tips of six lead members 222d each sandwiched by the slits 222c. An internal thread portion 221 formed on the inner periphery of the luer lock adapter 202 is configured to be screwed with an outer periphery of an outer flange 232 a provided at the rear end of the needle base 232 of the needle 203.

  Next, a procedure for fixing the needle base 232 of the injection needle 203 to the luer 211 formed at the tip of the outer cylinder 201 by the luer lock adapter 202 will be described. First, the locking hole 222 b opened at the center of the inner flange 222 a of the luer lock adapter 202 is inserted into the tapered outer periphery 211 a of the luer 211. As described above, the locking hole 222b is formed at the tip of the six lead members 222d. Therefore, if the luer lock adapter 202 is pressed in the insertion direction, the lead member bends backward, and the locking hole Expands in diameter. Therefore, the locking hole 222b can be easily fitted into the circumferential groove 211b formed on the outer periphery of the rear end portion of the luer 211.

  Since the groove bottom diameter of the circumferential groove 211b is formed slightly larger than the inner periphery of the locking hole 222b, the tips of the six lead members 222d are groove bottoms of the circumferential groove by their respective elastic forces. Tighten in the radial direction. Therefore, the luer lock adapter 202 is locked in the axial direction by engaging the locking hole 222b with the circumferential groove 211b, and further, between the inner periphery of the locking hole and the groove bottom of the circumferential groove. Are connected so as not to rotate with each other by the frictional force.

  Next, while the outer flange 232a provided at the rear end of the needle base 232 of the injection needle 203 is screwed into the female thread portion 221 formed on the inner periphery of the luer lock adapter 202, the inner periphery 232b of the needle base is moved to the lure. It is inserted into the outer periphery 211a of 211. When the outer flange 232a and the internal thread portion 221 are further screwed together, the cone-shaped inner periphery 232b of the needle base 232 comes into close contact with the outer periphery 211a of the tapered luer 211 and is strong in the axial direction and the radial direction. Both are connected in the pressed state. As described above, the injection needle 203 can be fixed to the outer cylinder 201 so as not to come off in the axial direction or rotate relative to each other.

  That is, in the above-described means, the boundary separating the inside and the outside of the syringe is only the mating surface of the inner periphery 232b of the needle base 232 of the injection needle 203 and the outer periphery 211a of the lure 211, and both are cones that are in close contact with each other. It is formed in a shape. Therefore, as described above, when the needle base 232 of the injection needle 203 is screwed into the female thread portion 221 of the luer lock adapter 202 and tightened, the mating surfaces of the two are mutually axially and radially like a wedge. It is in close contact with the direction strongly pressed. For this reason, it has the advantage that it can prevent easily and reliably that an injection solution leaks from the mating surface of both.

JP 2002-282358 A

  However, it has been found that the above-mentioned means have problems to be further improved. That is, in the above-described means, when the injection needle 203 is fixed to the distal end of the outer cylinder 201, the external thread 232a provided at the rear end of the needle base 232 of the injection needle is formed on the inner periphery of the luer lock adapter 202. Tighten while screwing into the part 221. Here, when the two are screwed together and tightened, if the luer lock adapter 202 idles with respect to the outer cylinder 201, the force for tightening the needle base 232 of the injection needle 203 to the outer periphery 211a of the luer 211 becomes weak. In such a case, the pressing force applied to both the cone-shaped mating surfaces described above is reduced, and the injection solution may leak to the outside.

  With the above-described means, the inner peripheral diameter of the locking hole 222b provided in the luer lock adapter 202 is made slightly smaller than the groove bottom diameter of the circumferential groove 211b formed in the luer 211, thereby ensuring a frictional force between them. This prevents the lure lock adapter from spinning around.

  However, it has been found that when an injection solution, a lubricant, or the like adheres to the inner periphery of the locking hole 222b or the circumferential groove 211b, the frictional force between them may not be ensured. In particular, since the inner periphery of the outer cylinder 201 is usually coated with silicon as a lubricant so that the plunger slides smoothly, the possibility that this silicon adheres to the circumferential groove 211b cannot be denied. Further, since the groove bottom diameter of the circumferential groove 211b is smaller than the diameter of the female screw portion 221, the rotational moment arm is shortened, which is disadvantageous in that a large anti-rotation torque is generated by the frictional force with the circumferential groove. It has a structure.

  Accordingly, an object of the present invention is to provide a luer lock adapter for a syringe that can avoid the idling of the luer lock adapter and reliably prevent leakage of the injection solution.

  In order to solve the above-mentioned problems, the luer lock adapter of the syringe according to the present invention is characterized in that a cylindrical fitting portion is provided at the rear end portion of the luer lock adapter, and a plurality of axial slits are formed in the fitting portion. Furthermore, the inner peripheral diameter located on the front side of the axial slit is made equal to or larger than the outer peripheral diameter of the outer cylinder, and the inner peripheral diameter at the rear end is made smaller than the outer peripheral diameter of the outer cylinder.

  That is, the luer lock adapter for a syringe according to the present invention is a luer lock adapter for fixing an injection needle to a lure formed by reducing the diameter of the tip of an outer cylinder of the syringe, and this luer tapers toward the tip. It applies to what has the outer periphery formed in the shape, and the circumferential groove formed in the rear-end part of this outer periphery. The luer lock adapter has a cylindrical shape made of synthetic resin, and has a female screw portion provided on the inner periphery of the tip portion thereof, a locking portion located on the rear side of the female screw portion, and a locking portion of the locking portion. And a fitting portion located on the rear side.

  The locking portion has an inner flange protruding from the inner periphery of the luer lock adapter, and a locking hole is opened at the center of the inner flange. The inner diameter of the locking hole is equal to or smaller than the groove bottom diameter of the circumferential groove, and the inner flange includes a plurality of radially extending inner diameters of the locking hole. Are formed at equal intervals in the circumferential direction.

  The fitting portion has an inner periphery to be inserted into the outer periphery of the outer cylinder, and a plurality of axial slits extending from the rear end to the front side are formed at equal intervals in the circumferential direction. The inner peripheral diameter of the fitting portion located in front of the front end of the axial slit is equal to or larger than the outer peripheral diameter of the outer cylinder, and at the rear end of the fitting section. The inner diameter is smaller than the outer diameter of the outer cylinder.

  Here, in order to clarify the characteristics of the present invention, the operational effects of the luer lock adapter of the syringe according to the present invention will be described. That is, by providing a cylindrical fitting portion at the rear end portion of the luer lock adapter and generating a frictional force between the inner periphery of this fitting portion and the outer periphery of the outer tube, Even when the frictional force between them decreases, it is possible to reliably prevent the luer lock adapter from idling. In particular, the fitting portion with the outer periphery of the outer cylinder has a larger rotational moment arm than the circumferential groove of the lure, which is extremely advantageous in that a large idling torque is generated.

  In addition to the above, by forming a plurality of axial slits in the fitting portion, the fitting dimensional accuracy with the outer periphery of the outer cylinder can be greatly relaxed. That is, when the fitting part is not provided with an axial slit, in order to reliably obtain a frictional force with the outer periphery of the outer cylinder, the outer periphery of the outer cylinder and the inner periphery of the fitting part are In any case, it is necessary to finish with high fitting dimensional accuracy. That is, if the fitting is loose, sufficient frictional force cannot be obtained, and conversely, if the fitting is tight, it becomes difficult to insert the fitting portion into the outer periphery of the outer cylinder.

  However, if a plurality of axial slits are provided in the fitting portion, the inner diameter of the fitting portion can be made smaller than the outer diameter of the outer tube with a relatively large difference in diameter. The fitting dimensional accuracy of the outer periphery and the inner periphery of the fitting portion can be greatly relaxed. That is, even if the outer periphery of the outer cylinder and the inner periphery of the fitting portion are tightly fitted, if the plurality of axial slits are provided, the fitting portion easily expands in diameter and can be easily inserted.

  Further, the luer lock adapter according to the present invention does not fall off in the axial direction because the locking hole is locked in the circumferential groove of the lure. Therefore, it is sufficient that the luer lock adapter and the outer cylinder do not rotate relative to each other, and it is possible to eliminate the formation of a protrusion or a groove in order to prevent the luer lock adapter and the outer cylinder from falling off in the axial direction.

  Furthermore, the inner peripheral diameter of the fitting portion located in front of the front end of the axial slit is equal to or larger than the outer peripheral diameter of the outer tube, and the inner peripheral diameter at the rear end of the fitting portion. By making the diameter smaller than the outer peripheral diameter of the outer cylinder, the fitting dimensional accuracy of the outer periphery of the outer cylinder and the inner periphery of the fitting portion can be further relaxed. That is, the inner circumference of the fitting portion located in front of the tip of the axial slit hardly expands, but if the inner circumference is made larger than the outer circumference of the outer cylinder, It can be easily inserted into the outer periphery. In addition, as described above, the inner peripheral diameter at the rear end of the fitting portion is easily increased by a plurality of axial slits, so even if the inner peripheral diameter is considerably smaller than the outer peripheral diameter of the outer cylinder, It can be easily inserted into the outer periphery of the cylinder. In other words, even if the dimensional accuracy between the inner periphery of the fitting part and the outer periphery of the outer cylinder is lowered, the inner peripheral diameter at the tip is made larger than this dimensional accuracy, and the inner peripheral diameter at the rear end is increased. If it is made smaller, the fitting portion of the luer lock adapter can be easily inserted into the outer cylinder, and a sufficient frictional force can be generated between the outer cylinder and the outer cylinder.

  Furthermore, as described above, the syringe according to the present invention reliably prevents the injection solution from leaking to the outside at the contact surface between the outer periphery of the cone-shaped luer and the inner periphery of the needle base of the injection needle. It is not necessary to consider leakage of the injection solution to the outside at the fitting portion between the outer periphery of the tube and the inner periphery of the fitting portion. Therefore, the fitting part of the luer lock adapter is provided with a plurality of axial slits, or a radial clearance is provided between the inner periphery of the fitting part and the outer periphery of the outer cylinder located in front of the tip of the axial slit. It can be provided.

  The luer lock adapter is formed by injection molding synthetic resin. In this case, it is necessary to use a core for forming the inner periphery of the fitting portion, that is, the inner space. As described above, the inner circumference of the fitting portion is smaller in diameter at the rear end than at the tip. Therefore, if the fitting portion does not expand in diameter, after injecting synthetic resin into the mold, The child cannot be extracted. In the present invention, by providing a plurality of axial slits in the fitting portion, the rear end can be enlarged in diameter, so that the core can be easily extracted.

  When the injection needle is screwed into the luer lock adapter according to the conventional example shown in FIG. 6, as described above, the injection needle and the luer lock adapter are fixed to the outer periphery and the circumferential groove of the lure. However, this lure has a smaller diameter than the outer cylinder of the syringe, and a circumferential groove is formed at the rear end of the lure, so that excessive force is inadvertently applied to the injection needle and luer lock adapter. If this happens, there is a risk of damage in the circumferential groove of this lure. Even when the injection needle is screwed into the luer lock adapter, if an excessive force is applied carelessly, there is a risk of damage in the circumferential groove of the lure.

  However, in the luer lock adapter according to the present invention, the fitting portion located on the rear end side is attached to the outer periphery of the outer cylinder having a large diameter of the syringe. Therefore, when the injection needle is excessively applied to the injection needle or luer lock adapter after or after the injection needle is attached to the lure via the luer lock adapter, It is possible to prevent breakage in the circumferential groove provided in.

  Here, “the outer cylinder of the syringe” means a hollow container made of a synthetic resin or glass having a constant outer diameter at least at a portion where a luer lock adapter is inserted. “Luer formed by reducing the diameter of the tip of the outer cylinder of the syringe” refers to a member that is integrally formed so as to protrude from the tip of the outer cylinder and connects the injection needle. It means one having a smaller tapered outer diameter and having a flow path for extracting an injection at the center. The “injection needle” means one having a cone-shaped inner periphery that is in close contact with the tapered outer periphery of the lure. The “circumferential groove” means a groove having a concave cross-sectional shape provided along the outer peripheral direction over the entire outer periphery of the lure, and the details of the cross-sectional shape are not limited. For example, the case of a rectangular, semi-circular or arc-shaped cross-sectional shape is applicable.

  The “synthetic resin” of the “synthetic resin luer lock adapter” corresponds to a thermoplastic resin such as polypropylene or polycarbonate. The “Lure Lock Adapter” is injection molded using a mold. The “internal thread part” means a part that is screwed with an external thread part provided on the outer periphery of the injection needle, but the thread shape, the thread diameter, the pitch, and the number of threads are not limited. “The inner circumferential diameter of the locking hole is equal to or smaller than the groove bottom diameter of the circumferential groove” in “the same as the groove bottom diameter of the circumferential groove” Because the frictional force between the inner circumference of the fitting part of the luer lock adapter and the outer circumference of the outer cylinder can sufficiently prevent the lure lock adapter from spinning, This is because the frictional force between the inner circumference and the circumferential groove of the lure is not always necessary. Therefore, “equivalent to the groove bottom diameter of the circumferential groove” includes the case where the inner diameter of the locking hole is slightly larger than the groove bottom diameter of the circumferential groove.

  If the inner peripheral diameter of the locking hole is made smaller than the groove bottom diameter of the circumferential groove as in the prior art, the frictional force between the inner periphery of the fitting portion of the luer lock adapter and the outer periphery of the outer cylinder is affected. Since the frictional force between the inner periphery of the blind hole and the circumferential groove of the lure is also applied, it is possible to more strongly prevent the lure lock adapter from idling. The “plurality” of the “plurality of radial slits” is preferably six, but may be at least two. The shape of the “radial slit” is not limited. The “plurality” of the “plurality of axial slits” is preferably three, but may be at least two. The shape of the “axial slit” is not limited.

  By the way, it is desirable to form the inner periphery of the fitting portion in a reverse taper shape whose diameter decreases toward the rear end. When the fitting portion is inserted into the outer circumference of the outer cylinder, the inner circumference of the portion where the axial slit is formed is expanded, and the inner circumference and the outer circumference of the outer cylinder can be brought into close contact with each other in a substantially parallel state. it can. Therefore, since the contact area can be widened, the frictional force can be increased.

  Further, a protrusion is provided along the circumferential direction on the inner periphery of the rear end of the fitting part, and the inner diameter formed by the top of the protrusion is smaller than the outer diameter of the outer cylinder. You may comprise. In addition, it is desirable to make the front side wall of a protrusion part into a gentle inclined surface. This is because the core can be extracted more easily after injection molding.

  Furthermore, the outer cylinder is desirably made of glass. In the case of a glass outer cylinder, compared to an outer cylinder that is generally made of plastic, injection-molded protrusions and grooves are formed on the part where the luer lock adapter is inserted. Difficult to do. However, in the present invention, as described above, it is not necessary to form a protrusion or concave groove for preventing the luer lock adapter from coming off at the portion where the luer lock adapter is inserted. Therefore, the luer lock adapter according to the present invention is more excellent in applicability to a glass outer cylinder in which it is difficult to form protrusions and concave grooves for retaining.

  While exhibiting the above-mentioned specific effects, it is possible to avoid the idle rotation of the luer lock adapter and reliably prevent the injection liquid from leaking.

It is sectional drawing of the outer cylinder which comprises a syringe, an injection needle, and a luer lock adapter. It is an expanded sectional view of a luer lock adapter. It is a front view of a luer lock adapter. It is a rear view of a luer lock adapter. It is a partially expanded sectional view of another luer lock adapter. It is sectional drawing of the outer cylinder, injection needle, and luer lock adapter which comprise the syringe by a prior art example. It is a front view of the luer lock adapter by a prior art example.

  An example of a luer lock adapter for a syringe according to the present invention will be described with reference to FIGS. That is, as shown in FIG. 1, the luer lock adapter 2 of the syringe according to the present invention is for fixing the injection needle 3 to the luer 11 formed by reducing the diameter of the tip of the outer cylinder 1 of the syringe. The outer cylinder 1 is made of glass, and the luer lock adapter 2 is formed by injection molding of a thermoplastic resin such as polycarbonate. The injection needle 3 has a structure in which a needle 31 is inserted at the tip of a needle base 32 made of synthetic resin.

  The lure 11 has an outer periphery 11a that is tapered toward the tip, and a circumferential groove 11b that is formed at the rear end of the outer periphery. As shown in FIG. 1, an outer flange 32 a formed in the shape of a male thread is provided at the rear end of the outer periphery of the needle base 32 of the injection needle 3. Further, the inner periphery 32 b of the needle base 32 is shaped like a cone closely contacting the tapered outer periphery 11 a of the lure 11. That is, the injection needle 3 inserts and attaches the cone-shaped inner periphery 32b of the needle base 32 to the tapered outer periphery 11a of the lure 11 to bring them into close contact. Therefore, the drug agent is structured not to leak to the outside.

  As shown in FIG. 2, the luer lock adapter 2 has a cylindrical shape, and an internal thread portion 21 is provided on the inner periphery of the tip portion. 22 are provided adjacent to each other. Further, a fitting portion 23 is provided adjacent to the rear side of the locking portion 22. The female screw portion 21 is formed in a shape that is screwed into an outer flange 32 a provided at the rear end of the needle base 32 of the injection needle 3.

  FIG. 3 shows a front shape of the luer lock adapter 2 viewed from the tip side. As shown in FIGS. 2 and 3, the locking portion 22 provided on the luer lock adapter 2 has an inner flange 22a projecting inward, and the center of the inner flange is a circular hole. A blind hole 22b is opened. The inner peripheral diameter of the locking hole 22b is equal to or slightly smaller than the groove bottom diameter of the circumferential groove 211b formed at the rear end of the outer periphery 211a of the lure 211. The inner flange 22a is provided with six slits 22c extending radially from the inner periphery of the locking hole 22b at equal intervals in the circumferential direction. That is, the locking hole 22b is formed by the tips of six lead members 22d each sandwiched by the slits 22c.

  On the outer periphery of the luer lock adapter 2, six ridges 25 are formed at equal intervals in the circumferential direction over the entire length in the axial direction. Since the luer lock adapter 2 can be secured by the protrusion 25, it is possible to reduce the thickness of other portions. It is also possible to prevent the syringe from rolling down when placed on a table or the like.

  FIG. 4 shows the back shape of the luer lock adapter 2 as viewed from the rear end side. As shown in FIGS. 2 and 4, the fitting portion 2 has an inner periphery 23 b that is inserted into the outer periphery of the outer cylinder 1, and three axial slits 23 a that extend from the rear end to the front side are provided in the circumferential direction. Are formed at equal intervals. As shown in FIG. 2, the inner periphery 23b of the fitting part 2 is formed in a reverse taper shape whose diameter decreases toward the rear end. Here, the diameter of the inner periphery 23b of the fitting portion 2 is slightly larger than the outer diameter of the outer cylinder 1 on the front side of the tip of the axial slit 23a. On the other hand, the diameter of the inner periphery 23b of the fitting portion 2 is smaller by 2 × ΔR than the outer periphery diameter of the outer cylinder 1 at the rear end.

  Therefore, when the fitting portion 23 of the luer lock adapter 2 is inserted into the outer cylinder 1, the inner periphery 23b does not expand on the front side where the axial slit 23a is not formed, but both are loosely fitted. Therefore, it can be inserted easily. On the other hand, at the rear end of the fitting portion 23, although the diameter of the inner periphery 23b is smaller than the outer periphery diameter of the outer cylinder 1 by 2 × ΔR, the diameter is easily expanded by the axial slit 23a. It can be easily inserted into the outer periphery of the outer cylinder. Further, when the reversely tapered inner circumference 23b of the fitting portion 23 is inserted into the outer cylinder 1, it is parallel to the outer circumference of the outer cylinder over almost the entire length, and a wide close area can be secured between the two. .

  In FIG. 5, the other form of a fitting part is shown. Note that parts equivalent to those shown in FIG. 2 are given the same reference numerals shown in FIG. 2 plus 100 for convenience of reference. Now, on the inner periphery 123b of the rear end of the fitting portion 123 of the luer lock adapter 102, a ridge portion 123c projects along the circumferential direction. The inner peripheral diameter formed at the top of the protrusion 123c is smaller than the outer peripheral diameter of the outer cylinder 101 by 2 × ΔR. The other portions of the luer lock adapter 102 are formed in the same manner as the luer lock adapter 2 described above.

  By configuring the luer lock adapter 102 in this way, on the front side where the axial slit 123a is not formed, the inner periphery 123b of the fitting portion 123 is formed larger than the outer diameter of the outer cylinder 101, or at the rear end, The inner circumference can be easily formed smaller than the outer diameter of the outer cylinder by 2 × ΔR. Even if the protrusion 123c is provided at the rear end of the fitting portion 123, the diameter of the rear end of the fitting portion can be increased by the three axial slits 123a1, and the core after the injection molding is performed. Can be easily extracted.

  Since the lure lock adapter can be prevented from idling and the injection solution can be reliably prevented from leaking, it can be widely used in the industry related to syringes.

1, 101, 201 Outer cylinder 11, 211 Luer 11a, 211a Outer periphery 11b, 211b Circumferential groove 2, 102, 202 Luer lock adapter 21, 221 Female thread portion 22, 222 Locking portion 22a, 222a Inner flange 22b, 222b Locking Hole 22c, 222c Radial slit 23, 123 Fitting part 23a, 123a Axial slit 23b, 123b Inner circumference 123c Projection

Claims (4)

A luer lock adapter for fixing an injection needle to a lure formed by reducing the diameter of the tip of an outer cylinder of a syringe,
The lure has an outer periphery that is tapered toward the tip, and a circumferential groove formed at the rear end of the outer periphery.
The luer lock adapter has a cylindrical shape made of synthetic resin, and has a female screw portion provided on the inner periphery of the tip portion thereof, a locking portion located on the rear side of the female screw portion, and a locking portion of the locking portion. A fitting portion located on the rear side,
The locking portion has an inner flange protruding from the inner periphery of the luer lock adapter, and a locking hole is opened at the center of the inner flange.
The inner peripheral diameter of the locking hole is equal to or smaller than the groove bottom diameter of the circumferential groove,
In the inner flange, a plurality of radial slits extending radially from the inner periphery of the locking hole are formed at equal intervals in the circumferential direction,
The fitting portion has an inner circumference to be inserted into the outer circumference of the outer cylinder, and a plurality of axial slits extending from the rear end to the front side are formed at equal intervals in the circumferential direction,
The inner peripheral diameter of the fitting portion located on the front side from the tip of the axial slit is equal to or larger than the outer peripheral diameter of the outer cylinder,
An inner diameter at the rear end of the fitting portion is smaller than an outer diameter of the outer cylinder. The luer lock adapter for a syringe according to claim 1, wherein an inner periphery of the fitting portion is formed in a reverse taper shape whose diameter decreases toward the rear end thereof. On the inner periphery of the rear end of the fitting portion, a protruding portion protrudes along the circumferential direction,
The luer lock adapter for a syringe according to claim 1, wherein the inner peripheral diameter formed at the top of the ridge is smaller than the outer peripheral diameter of the outer cylinder. The luer lock adapter for a syringe according to any one of claims 1 to 3, wherein the outer cylinder is made of glass.

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