JP5066973B2 - Combination structure of plunger rod and gasket and syringe - Google Patents

Description

  The present invention relates to a coupling structure of a plunger rod and a gasket and a syringe.

  Conventionally, in a manufacturing site of a so-called prefilled syringe filled with a chemical solution, a plunger rod is coupled to the gasket after filling the syringe body with the chemical solution and inserting the gasket into the syringe body. The reason why the gasket insertion process is performed in this manner is that it becomes an obstacle when the plunger rod is assembled in the subsequent sterilization process.

  As a method for joining the plunger rod and gasket of the prefilled syringe, for example, there is a method in which a plunger rod is press-fitted into the gasket. Therefore, the plunger rod must be pressed with a strong force. For this reason, a gasket will be pushed into a syringe main body, and there exists a possibility that a chemical | medical solution may leak from a front-end | tip nozzle.

  As a coupling structure between the plunger rod and the gasket that can avoid this, for example, a gasket made of a material having rubber elasticity such as butyl rubber or elastomer is screwed to a plunger rod made of plastic such as polypropylene, so that the plan A structure for joining a jar rod and a gasket is known (for example, see Patent Document 1).

A columnar portion protrudes from the tip of the plunger rod of Patent Document 1. A convex portion is formed at the base end portion of the columnar portion, and a male screw portion is provided on the outer peripheral surface of the columnar portion. On the other hand, the gasket of Patent Document 1 includes a cylindrical portion into which a columnar portion is inserted, and a bottom wall portion formed so as to close a side opposite to the side where the columnar portion is inserted in the cylindrical portion. Yes. On the inner peripheral surface of the cylindrical portion, a female screw portion that is screwed into the male screw portion is provided, and in addition, a protruding portion of the columnar portion is formed on the open portion opposite to the bottom wall portion of the cylindrical portion. A recess into which the part fits is provided. Therefore, when the male thread part of the plunger rod is screwed into the female thread part of the gasket, the convex part is fitted into the concave part. When this convex part fits into the concave part, for example, when the prefilled syringe after completion is transported by a car or due to vibration generated in the manufacturing process, the male screw part and the female screw part are difficult to loosen.
JP 2005-80957 A

  However, in the thing of patent document 1, since the convex part is provided in the base end part of the columnar part of a plunger rod, the recessed part of the gasket which this convex part fits is on the opposite side to the bottom wall part of a cylindrical part. It will be provided in the open part. Since the open part of the cylindrical part of this gasket is low in rigidity and easily deformed, depending on the strength of vibration during transportation or manufacture, the cylindrical part may be deformed, and the convex part of the plunger rod will protrude from the concave part. There is a risk of withdrawal. If it becomes like this, a male screw part and a female screw part will loosen, and a plunger rod will fall off.

  The present invention has been made in view of such a point. The purpose of the present invention is to connect the plunger rod and the gasket by screwing of the screw, so that the screw is not moved by vibration during transportation or manufacturing. It is to ensure that it is not loosened.

The invention of claim 1 is a coupling structure of the gasket having a plunger rod having a columnar portion, the rubber elasticity above the columnar portion is formed in a bottomed cylindrical shape which is inserted protruding from the distal end, the columnar portion forms a cylindrical shape which is continuous in the circumferential direction, the first threaded portion is provided on the outer peripheral surface of the columnar portion, the projecting forward end side of the columnar portion, the engaging portion is provided, in the gasket Is provided with a second threaded portion that engages with the first threaded portion on the inner peripheral surface thereof, and an engaged portion with which the engaging portion engages at a portion corresponding to the engaging portion, One of the engaging portion and the engaged portion is a convex portion protruding in a radial direction from the inner peripheral surface of the columnar portion or the inner peripheral surface of the gasket, and the other is so that the convex portion enters. It is a recessed part recessed in radial direction, The protrusion height of the radial direction of the said convex part is a said 1st screw part and a said 2nd Set the di portion to be gradually lower toward the rotation direction when the screwing, the first screw portion in a state that is screwed into the second threaded section, enter the convex portion to the concave portion The plunger rod and the gasket are combined .

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of engaging portions and engaged portions are provided at intervals in the rotational direction when the first screw and the second screw are screwed together. The configuration .

According to a third aspect of the present invention, in the first aspect of the present invention, the outer surface of the convex portion and the inner surface of the concave portion contact each other from the direction opposite to the rotational direction when the first screw portion and the second screw portion are screwed together. A contact portion that is in contact with each other is provided .

According to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the columnar portion is formed in a cylindrical shape that opens to the tip surface, and an engagement portion is provided on the inner surface of the columnar portion. The engaged portion is inserted into the columnar portion.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the plunger rod and the gasket are used for a prefilled syringe in which a liquid medicine is prefilled in a syringe body.

A sixth aspect of the present invention is a syringe provided with the coupling structure of the plunger rod and the gasket according to any one of the first to fifth aspects .

According to the first aspect of the present invention, since the engaging portion of the plunger rod is provided on the front end side in the protruding direction of the columnar portion, the engaged portion of the gasket is provided on the bottom wall portion side. . Since the bottom wall portion side of this gasket is higher in rigidity than the open side, when the first screw portion and the second screw portion are screwed together, the engaging portion can be firmly engaged with the engaged portion. it can. Thereby, it can suppress that the screwing state of a 1st screw part and a 2nd screw part loosens, and can prevent the dropping of a plunger rod at the time of transportation and manufacture of a syringe .

According to the invention of claim 2 , since the plunger rod and the gasket are engaged at a plurality of locations, a more powerful loosening suppression effect can be obtained .

According to the third aspect of the present invention, for example, the plunger rod is rotated in the loosening direction of the first screw portion in a state where the first screw portion and the second screw portion are screwed together and the convex portion is fitted in the concave portion. In this case, the contact part of the convex part and the contact part of the concave part contact each other. Thereby, a more powerful loosening suppression effect can be obtained .

According to the invention of claim 4, since the engaged portion of the gasket is inserted into the columnar portion of the plunger rod, the combined length of the gasket and the plunger rod in a state where the gasket is coupled. Can be made longer and can be easily handled at the time of injection.

According to the invention of claim 5 , it is possible to prevent the plunger rod from falling off in the prefilled syringe. Therefore, a highly reliable prefilled syringe can be provided.

According to invention of Claim 6 , a highly reliable syringe can be provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  FIG. 1 shows a prefilled syringe 10 to which a coupling structure of a plunger rod and a gasket according to an embodiment of the present invention is applied.

  As shown in FIGS. 2 and 3, the prefilled syringe 10 is made of a cylindrical syringe body 11 filled with a chemical solution 12, a gasket 30 made of a material having rubber elasticity, and a resin material harder than the gasket 30. The plunger rod 20 is provided. A nozzle portion 13 is provided at the distal end portion of the syringe body 11. The nozzle portion 13 is sealed with a cap 14. The gasket 30 is inserted into the syringe body 11 from the base end side (the right side in FIG. 1) that is the rear end side of the syringe body 11. The gasket 30 seals the rear end side of the syringe body 11. The distal end of the plunger rod 20 in the insertion direction into the syringe body 11 is coupled to the gasket 30.

  As shown in FIG. 6, the distal end surface portion 21 in the insertion direction of the plunger rod 20 is provided with a columnar portion 22 having a circular cross section at the center thereof so as to protrude toward the distal end side in the insertion direction of the plunger rod 20. Yes. The columnar portion 22 has a hollow cylindrical shape that opens to the distal end side in the insertion direction. A male screw portion (first screw portion) 23 is provided on the outer peripheral surface of the columnar portion 22 from the distal end to the proximal end. As shown in FIGS. 7 and 8, four convex portions (engagement portions) 25 extending from the base end portion to the distal end portion of the columnar portion 22 are provided on the inner surface of the columnar portion 22. These convex portions 25 are arranged at the same interval in the circumferential direction of the columnar portion 22. The protrusion 25 protrudes from the inner surface of the columnar portion 22 in the rotation direction when the male screw portion 23 is screwed, that is, in the rotation direction when tightening (the direction indicated by the arrow W in FIG. 7). Is formed so as to be gradually lowered.

  On the other hand, as shown in FIGS. 4 and 5, the gasket 30 closes the cylindrical cylindrical portion 31 into which the columnar portion 22 is inserted, and the side opposite to the insertion direction of the columnar portion 22 in the cylindrical portion 31. It is formed in the bottomed cylinder shape provided with the bottom wall part 32 to do. The outer peripheral surface of the cylindrical part 31 is formed so as to correspond to the shape of the inner peripheral surface 11 a of the syringe body 11. A female screw portion (second screw portion) 33 that is screwed into the male screw portion 23 is formed on the inner peripheral surface of the cylindrical portion 31. On the outer peripheral surface of the cylindrical portion 31, there is a protruding portion 34 that contacts the inner peripheral surface 11 a of the syringe body 11 of the prefilled syringe 10 and seals between the inner peripheral surface 11 a and the cylindrical portion 31. Two are provided apart in the axial direction of 31 (in the direction of insertion into the syringe body 11). The inner surface of the bottom wall portion 32 extends in a direction substantially orthogonal to the axis of the cylindrical portion 31. A bulging portion 35 that bulges toward the open side of the cylindrical portion 31 is formed at the center of the inner surface of the bottom wall portion 32. The front end surface of the bulging portion 35 is formed to be substantially flat. Four concave portions (engaged portions) 36 are provided on the outer peripheral surface of the bulging portion 35. These concave portions 36 are arranged at the same interval in the circumferential direction of the cylindrical portion 31 like the convex portions 25. The depth of the concave portion 36 changes in the circumferential direction of the cylindrical portion 31 so as to correspond to the shape of the convex portion 25.

  Further, on the outer surface of the convex portion 25 and the inner surface of the concave portion 36, contact portions 25a (shown in FIG. 7) and 36a (shown in FIG. 4) extending in the radial direction of the plunger rod 20 are formed. These contact parts 25a and 36a contact each other from the direction opposite to the rotation direction when the male screw part 23 and the female screw part 33 are screwed together.

  Next, the point which manufactures the said prefilled syringe 10 is demonstrated. First, as shown in FIG. 1, after the nozzle portion 13 of the syringe body 11 is sealed with a cap 14, the chemical solution 12 is injected into the syringe body 11. And the gasket 30 is inserted in the syringe main body 11 from the rear-end part, and the plunger rod 20 and the gasket 30 are combined as shown in FIG.

  Hereinafter, the joining process of the plunger rod 20 and the gasket 30 will be described in detail. First, the columnar portion 22 of the plunger rod 20 is pushed into the cylindrical portion 31 of the gasket 30 from the tip side, and at the same time, the plunger rod 20 is rotated in the screwing direction. Thereby, the male thread portion 23 of the plunger rod 20 is screwed into the female thread portion 33 of the gasket 30, and the columnar portion 22 enters the bottom wall portion 32 side of the cylindrical portion 31. At the final stage of the screwing operation of the male screw portion 23, the bulging portion 35 of the gasket 30 is inserted into the columnar portion 22, and the convex portion 25 of the columnar portion 22 is formed as indicated by a virtual line in FIG. The concave portion 36 of the bulging portion 35 enters and the convex portion 25 engages with the concave portion 36. The plunger rod 20 is rotated in the screwing direction until the convex portion 25 completely enters the concave portion 36.

  In the operation of screwing the male screw portion 23 into the female screw portion 33, the shape of the convex portion 25 is formed so as to be gradually lowered toward the rotation direction when screwing, so that the plunger rod The rotational force when rotating 20 in the screwing direction is low, and the male screw portion 23 can be smoothly screwed into the female screw portion 33. Further, since the gasket 30 has rubber elasticity, when the convex portion 25 enters the concave portion 36, the concave portion 36 is elastically deformed. Therefore, the convex part 25 can enter the concave part 36 with a small force.

  On the other hand, when the plunger rod 20 is about to rotate in the direction opposite to the screwing direction (slack direction) in the state where the screwing is completed, the contact parts 25a and 36a contact each other. Furthermore, since four sets of the convex part 25 and the recessed part 36 are provided, the plunger rod 20 and the gasket 30 will be engaged in four places. As a result, rotation of the plunger rod 20 in the loosening direction is prevented, and loosening between the male screw portion 23 and the female screw portion 33 is suppressed.

  As described above, the plunger rod 20 and the gasket 30 are joined together, and the prefilled syringe 10 is completed.

  Therefore, according to this embodiment, since the convex portion 25 of the plunger rod 20 is located on the front end side in the protruding direction of the columnar portion 22, the concave portion 36 of the gasket 30 can be provided on the bottom wall portion 32 side. it can. Since the bottom wall portion 32 side of the gasket 30 has higher rigidity than the open side, when the male screw portion 23 and the female screw portion 33 are screwed together, the convex portion 25 can be firmly engaged with the concave portion 36. it can. Thereby, it can suppress that the screwing state of the external thread part 23 and the internal thread part 33 loosens, and can prevent the plunger rod 20 from falling off during transport, manufacture, or use of the prefilled syringe 10.

  In addition, since the recess 36 of the gasket 30 is inserted into the columnar portion 22 of the plunger rod 20, the combined length of the gasket 30 and the plunger rod 20 with the gasket 30 joined increases. Can be avoided and easy to handle at the time of injection.

  In addition, the number of the convex parts 25 and the recessed parts 36 is not restricted to four, Three or less may be sufficient and five or more may be sufficient.

  Moreover, you may form deeply the recessed part 36 of the bulging part 35 of the gasket 30 like the modification 1 shown in FIG.

  10 to 13, four concave portions (engagement portions) 28 are provided on the outer surface of the columnar portion 22 of the plunger rod 20, and these concave portions 28 are engaged with the gasket 30. It may be. In the second modification, as shown in FIG. 11, the recesses 28 are arranged at the same interval in the circumferential direction of the columnar part 22. Each concave portion 28 is cut out over the front end surface of the columnar portion 22 on the front end side of the male screw portion 23 of the columnar portion 22. On the other hand, as shown in FIGS. 12 and 13, a recess 38 is formed on the inner surface of the bottom wall portion 32 of the gasket 30. Four convex portions (engaged portions) 39 are provided on the inner peripheral surface of the recessed portion 38. These convex portions 39 are arranged at the same interval in the circumferential direction like the concave portion 28, and enter the concave portion 28. Accordingly, when the male screw portion 23 is screwed into the female screw portion 33, the convex portion 39 enters the concave portion 28, and the convex portion 39 is engaged with the concave portion 28. Thereby, it can suppress that the screwing state of the external thread part 23 and the internal thread part 33 loosens. In addition, since the bottom wall portion 32 can be made thin by providing the recess portion 38 in the bottom wall portion 32 of the gasket 30, it is easy to fill the cavity of the mold with rubber as a material at the time of molding. Can be prevented. Note that the number of the convex portions 39 and the concave portions 28 is not limited to four.

  Moreover, the coupling structure of the plunger rod and the gasket according to the present invention can be applied to syringes other than the prefilled syringe 10.

  The present invention can be applied to, for example, a prefilled syringe for medical use.

It is a fragmentary sectional view which shows the state before couple | bonding a plunger rod with the gasket of the prefilled syringe which concerns on embodiment of this invention. It is a fragmentary sectional view which expands and shows the plunger rod front end side before coupling | bonding and the rear-end part of a syringe main body. FIG. 3 is a view corresponding to FIG. 2 in a state where a plunger rod and a gasket are coupled. It is a top view which expands and shows a gasket. It is the VV sectional view taken on the line in FIG. It is a side view of a plunger rod. It is the figure which looked at the plunger rod from the front end side. It is a fragmentary sectional view by the side of the tip of a plunger rod. FIG. 5 is a diagram corresponding to FIG. 4 according to Modification 1 of the embodiment. FIG. 7 is a view corresponding to FIG. 6 according to a second modification of the embodiment. FIG. 9 is a view corresponding to FIG. 7 according to a second modification of the embodiment. FIG. 5 is a diagram corresponding to FIG. 4 according to a second modification of the embodiment. FIG. 6 is a view corresponding to FIG. 5 according to Modification 2 of the embodiment.

DESCRIPTION OF SYMBOLS 10 Prefilled syringe 20 Plunger rod 22 Columnar part 23 Male thread part (1st thread part)
25 Convex part (engagement part)
25a Contact part 30 Gasket 33 Female thread part (2nd thread part)
36 Concave part (engaged part)
36a Contact part

Claims (6)

It is a coupling structure of a plunger rod having a columnar portion protruding from a tip portion and a gasket having rubber elasticity formed in a bottomed cylindrical shape into which the columnar portion is inserted,
The columnar part has a cylindrical shape continuous in the circumferential direction, a first screw part is provided on the outer peripheral surface of the columnar part, and an engaging part is provided on the front end side in the protruding direction of the columnar part,
The gasket is provided with a second threaded portion that engages with the first threaded portion on an inner peripheral surface thereof, and an engaged portion with which the engaging portion engages with a portion corresponding to the engaging portion. Provided,
One of the engaging portion and the engaged portion is a convex portion protruding in a radial direction from the inner peripheral surface of the columnar portion or the inner peripheral surface of the gasket, and the other is so that the convex portion enters. A recess recessed in the radial direction,
The projecting height in the radial direction of the convex portion is set so as to gradually decrease in the rotational direction when the first screw portion and the second screw portion are screwed together,
The plunger rod and the gasket are coupled by inserting the convex portion into the concave portion with the first screw portion screwed into the second screw portion. And gasket connection structure.   2. The plunger rod according to claim 1, wherein a plurality of engaging portions and engaged portions are provided at intervals in a rotation direction when the first screw and the second screw are screwed together. And gasket connection structure.   The outer surface of the convex portion and the inner surface of the concave portion are respectively provided with contact portions that contact each other from the direction opposite to the rotation direction when the first screw portion and the second screw portion are screwed together. The coupling structure of the plunger rod and gasket according to claim 1. The columnar part is formed in a cylindrical shape that opens to the front end surface, and an engagement part is provided on the inner surface of the columnar part,
Coupling structure of the plunger rod and the gasket according to the engaged portion of the gasket any one of claims 1 to 3, characterized in that it is inserted into the interior of the columnar section.   The plunger rod and gasket according to any one of claims 1 to 4, wherein the plunger rod and the gasket are used for a prefilled syringe in which a chemical liquid is prefilled in a syringe body. And the combined structure.   The syringe provided with the coupling structure of the plunger rod and gasket as described in any one of Claim 1 to 5.

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