JP2007289676A - Connecting structure of plunger rod and gasket and syringe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make the entire length of a plunger rod and a length of a gasket in the axial direction short while ensuring the connection of the plunger rod and the gasket for the easy manipulation. <P>SOLUTION: A columnar part 22 is provided on a distal end surface part 21 of the plunger rod 20. A first thread part 23 is provided on the peripheral surface of the columnar part 22. A cylindrical part 31 where the columnar part 22 is inserted is provided on the gasket 30. A second thread part 33 screwed with the first thread part 23 is provided on the inner peripheral surface of the cylindrical part 31. Protrusions cutting 24 into the cylindrical part 31 of the gasket 30 are provided on the first thread part 23. <P>COPYRIGHT: (C)2008,JPO&INPIT

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. However, in this method, the gasket inserted into the syringe body is difficult to spread in the radial direction. 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, the plunger rod made of plastic such as polypropylene is screwed into the gasket made of rubber elastic material such as butyl rubber or elastomer. 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 is provided with the cylindrical part in which a columnar part is inserted, and the female thread part screwed together with the said external thread part is provided in the internal peripheral surface of this cylindrical part. Moreover, the cylindrical part is provided with a concave part that fits into the convex part of the plunger rod. 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. By fitting the convex portion into the concave portion, for example, when the prefilled syringe after completion is transported by a car, or the male screw portion and the female screw portion are less likely to loosen due to vibration or the like generated in the manufacturing process.
JP 2005-80957 A

  However, in the invention of Patent Document 1, since the convex portion is provided at the base end portion of the columnar portion of the plunger rod, the male screw portion cannot be formed at the base end portion of the columnar portion. On the other hand, the portion where the male screw portion is formed cannot be shortened in the protruding direction of the columnar portion in order to ensure the coupling with the gasket, and it is necessary to ensure a predetermined length. Therefore, in the thing of patent document 1, it is necessary to secure the formation part of a male screw part by lengthening the projection length of a columnar part by the part which provided the convex part in the base end part of a columnar part, The total length of the plunger rod will be longer. In addition, when the protruding length of the columnar part is increased in this way, the gasket also becomes longer in the axial direction. When the plunger rod and the gasket become longer as described above, the length of the prefilled syringe as a whole becomes longer, and it becomes difficult for the operator to handle the injection of the drug solution.

  The present invention has been made in view of such points, and the object of the present invention is to reduce the total length of the plunger rod and the length of the gasket in the axial direction while ensuring the coupling between the plunger rod and the gasket. To make it short and easy to handle.

  The invention of claim 1 is a coupling structure of a plunger rod having a columnar part protruding from a tip part and a gasket having a cylindrical part into which the columnar part is inserted, and the outer peripheral surface of the columnar part has The first screw portion is provided, and the inner peripheral surface of the cylindrical portion is provided with a second screw portion that is screwed to the first screw portion, and the first screw portion and the second screw portion. At least one is provided with a loosening suppression portion that suppresses the loosening of the first screw portion and the second screw portion in a screwed state.

  According to a second aspect of the present invention, in the first aspect of the present invention, the looseness suppressing portion is constituted by a protrusion formed on the first screw portion of the plunger rod.

  The invention according to claim 3 is the invention according to claim 2, wherein a plurality of protrusions are formed on the peak portion of the first threaded portion, and the plunger rod and gasket coupling structure according to claim 2 .

  According to a fourth aspect of the present invention, in the second aspect of the present invention, a plurality of protrusions are formed in a valley portion of the first screw portion.

  According to a fifth aspect of the present invention, in any one of the second to fourth aspects of the present invention, the protrusion is formed to have a saw blade shape.

  According to a sixth aspect of the present invention, in any one of the second to fifth aspects of the present invention, the protrusion is gradually lowered toward the rotation direction when the first screw portion and the second screw portion are screwed together. The structure is formed.

  According to a seventh aspect of the present invention, in the invention according to any one of the second to sixth aspects, the protrusion is formed over the entire muscle direction of the first screw portion.

  According to an eighth aspect of the present invention, in the invention according to any one of the second to seventh aspects, the cylindrical portion of the gasket is formed with a recess into which the protrusion is fitted.

  According to a ninth aspect of the present invention, in any one of the second to eighth aspects of the present invention, the protrusion is provided at an intermediate portion in the protruding direction of the columnar portion.

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

  The invention of claim 11 is a syringe provided with the coupling structure of the plunger rod and gasket according to claims 1 to 10.

  According to the first aspect of the present invention, when the first screw portion of the plunger rod and the second screw portion of the gasket are screwed together, the screwed state between the first screw portion and the second screw portion is caused by the loosening suppression portion. It can suppress loosening. Thereby, the coupling | bonding of a plunger rod and a gasket can be ensured, and dropping of a plunger rod can be prevented at the time of conveyance, manufacture, and use. Moreover, since the slack suppression part is provided in at least one of the 1st screw part and the 2nd screw part, it does not need to lengthen the protrusion length of the columnar part of a plunger rod. Therefore, the total length of the plunger rod and the length of the gasket in the axial direction can be made shorter than the conventional one, and the operator can easily handle it.

  According to the invention of claim 2, since the projection is provided on the first threaded portion of the plunger rod, the first threaded portion and the second threaded portion can be obtained even when a generally used gasket is used as it is. Can be prevented from loosening.

  According to the invention of claim 3, the first screw portion of the plunger rod and the second screw portion of the gasket are screwed together so that the projection of the first screw portion is in a wide range of the valley portion of the second screw portion. It can be made to contact, and a more powerful loosening suppression effect can be acquired.

  According to the invention of claim 4, since the projection is provided in the valley portion of the first screw portion, the projection is difficult to hit another object until the first screw portion is screwed to the second screw portion, The damage and deformation of the protrusion can be prevented.

  According to the fifth aspect of the present invention, when the first screw portion of the plunger rod and the second screw portion of the gasket are screwed together, the protrusions bite into the second screw portion, and thus more powerful loosening suppression. An effect can be obtained.

  According to the invention of claim 6, since the shape of the protrusion is gradually lowered toward the rotation direction when the first screw portion and the second screw portion are screwed together, the first screw portion and the second screw portion The force required when screwing the threaded portion can be reduced.

  According to the invention of claim 7, since the protrusion is formed in a wide range, a stronger effect of suppressing loosening can be obtained.

  According to the eighth aspect of the present invention, when the first screw portion and the second screw portion are screwed together, the projection of the first screw portion fits into the recess of the gasket, so that a stronger loosening suppression effect can be obtained. .

  According to the ninth aspect of the present invention, by providing the protrusion at the intermediate portion in the protruding direction of the columnar portion, the screwing operation can be facilitated at the initial stage of screwing of the plunger rod and the gasket. Further, in the completely screwed state, the protrusion can be positioned deep in the cylindrical portion of the gasket. Thereby, a protrusion can be made to bite into the site | part which is hard to deform | transform a gasket, and the high loosening suppression effect can be acquired.

  According to the invention of claim 10, 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 11, 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.

  The prefilled syringe 10 includes a cylindrical syringe body 11 filled with a chemical solution 12, a gasket 30 made of a material having rubber elasticity, and a plunger rod 20 made of a resin material harder than the gasket 30. 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.

  A columnar portion 22 is provided on the distal end surface portion 21 of the plunger rod 20 in the insertion direction so as to protrude toward the distal end side in the insertion direction of the plunger rod 20. As shown in FIG. 2, the columnar portion 22 has a hollow 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. As shown in FIGS. 4 to 6, a large number of protrusions 24 are formed on the top of the mountain portion of the male screw portion 23 so as to be continuously arranged over the entire strip direction of the screw portion 23, that is, the muscle direction. Yes. Each protrusion 24 has a distal end portion 24a in the rotational direction when the male screw portion 23 is screwed, that is, the rotational direction at the time of tightening (the direction indicated by the arrow W in FIGS. 4 and 5) compared to the proximal end portion 24b. The base end 24b of the protrusion 24 is pointed. The base end 24b of the protrusion 24 is sharp. That is, each protrusion 24 is formed so as to gradually become lower in the rotation direction when the male screw portion 23 is screwed together. Thus, by setting the shape of each protrusion 24, the protrusion 24 has a saw-tooth shape at the mountain portion of the male screw portion 23. This protrusion 24 constitutes the loosening suppression portion of the present invention.

  On the other hand, as shown in FIGS. 2 and 3, the gasket 30 includes a cylindrical portion 31 into which the columnar portion 22 is inserted and a bottom wall that closes the opposite side of the cylindrical portion 31 in the insertion direction of the columnar portion 22. Part 32. 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 is a flat surface that is substantially orthogonal to the axis of the cylindrical portion 31. In addition, a recess may be provided on the inner surface of the bottom wall portion 32 so as to reduce the thickness of the bottom wall portion 32 and improve the moldability. Examples of the shape of the recess include a conical shape.

  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. As a result, 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. In this screwing operation, the protrusion 24 of the plunger rod 20 contacts the valley of the female thread 33, so that the valley of the female thread 33 of the gasket 30 is deformed corresponding to the shape of the protrusion 24. The protrusion 24 is in a state of being bitten into the valley portion of the female screw portion 33 of the gasket 30. When the male screw portion 23 is screwed to the female screw portion 33 to the end, the plunger rod 20 and the gasket 30 are joined, and the prefilled syringe 10 is completed.

  In the operation of screwing the male screw portion 23 into the female screw portion 33, the protrusion 24 of the male screw portion 23 is formed so as to gradually become lower in the rotation direction when the male screw portion 23 is screwed. Therefore, the rotational force when rotating the plunger rod 20 in the screwing direction is low, and the male screw portion 23 can be smoothly screwed into the female screw portion 33. On the other hand, in the state where the screwing is completed, the projection 24 of the male screw portion 23 is gradually increased from the distal end portion 24a to the proximal end portion 24b, and the proximal end portion 24b is sharpened. When the jar rod 20 is about to rotate in the direction opposite to the screwing direction, the protrusion 24 surely bites into the female threaded portion 33 of the gasket 30 and is prevented from rotating, and the male threaded portion 23 and the female threaded portion 33 are prevented from rotating. Looseness is suppressed.

  Therefore, according to this embodiment, the projection 24 of the male screw 23 of the plunger rod 20 bites into the valley of the female screw 24 of the gasket 30, so that the male screw is used during transportation, manufacture, and use of the prefilled syringe 10. Looseness between the portion 23 and the female screw portion 33 can be suppressed, and the plunger rod 20 can be prevented from being detached from the gasket 30. Further, since the protrusion 24 is provided on the male screw portion 23, the protrusion length of the columnar portion 22 of the plunger rod 20 is made longer than in the case where the protrusion 24 is provided at the base end portion of the columnar portion of the plunger rod as in the prior art. You do n’t have to. Therefore, the overall length of the plunger rod 20 can be shortened, and the axial dimension of the gasket 30 can be shortened. As a result, the prefilled syringe 10 can be easily handled by the operator at the time of injection.

  In the above embodiment, the protrusion 24 is provided on the top of the mountain portion of the male screw portion 23. However, the present invention is not limited to this, but may be provided on the side surface of the mountain portion of the male screw portion 23. In this case, when the male screw portion 23 is screwed, when the columnar portion 22 is pushed into the cylindrical portion 31 of the gasket 30, it is preferable to provide the protrusion 24 on the side surface opposite to the pushing direction. In this way, when the male screw portion 23 is screwed, if the columnar portion 22 is pushed into the cylindrical portion 31 of the gasket 30, the protrusion 24 becomes difficult to come into contact with the female screw portion 33. It can be performed more smoothly. In addition, when the columnar portion 22 of the plunger rod 20 is pulled out from the cylindrical portion 31 of the gasket 30, the protrusion 24 of the male screw portion 23 of the columnar portion 22 is formed into the female screw portion of the cylindrical portion 11. Thus, the plunger rod 20 can be reliably prevented from coming off from the gasket 30.

  Further, for example, as in the first modification shown in FIG. 7, the protrusions 224 (slack suppression portions) may be provided only at the valleys without providing the protrusions 24 at the peaks of the male screw 23. The protrusion 224 is provided continuously over the entire muscle direction of the male screw portion 23. By providing the protrusions 224 at the valleys of the male screw part 23 as in the second modification, when the columnar part 22 of the plunger rod 20 before being joined to the gasket 30 comes into contact with another object, the protrusions 224 Damage and deformation can be prevented. Therefore, the protrusion 224 can be maintained in a sharp shape, and the loosening suppression effect can be further enhanced.

  In the above-described embodiment, the protrusions 24 and 224 are provided in the entire muscle direction of the male screw portion 23. However, the protrusions 24 and 224 are only provided on a part of the male screw portion 23 in the muscle direction, for example, on the distal end side of the columnar portion 22. May be provided. Similarly, the protrusions 24 and 224 may be provided only on the base end side of the columnar portion 22, or may be provided only on the intermediate portion in the protruding direction of the columnar portion 22. Moreover, in the said embodiment, although protrusion 24,224 is continuously provided in the muscle direction of the external thread part 23, you may make it provide not only in this but multiple places intermittently in a muscle direction.

  When the protrusions 24 and 224 are provided only on the distal end side of the columnar portion 22 of the plunger rod 20, the protrusions 24 and 224 are in the bottom wall portion of the gasket 30 in a state where the plunger rod 20 and the gasket 30 are screwed together. It will be located on the 32 side. The bottom wall portion 32 side of the gasket 30 is a portion that is highly rigid and difficult to deform because the bottom wall portion 32 is integrally formed. Therefore, the protrusions 24 and 224 surely bite into the female thread portion 33 of the gasket 30, and the loosening suppression effect can be further enhanced.

  On the other hand, when the protrusions 24 and 224 are provided only on the base end side of the columnar portion 22 of the plunger rod 20, the protrusions 24 and 224 are formed on the gasket 30 at the initial stage of screwing of the plunger rod 20 and the gasket 30. It does not bite into the female screw part 33, but bites in at the stage of approaching the end of screwing. That is, in the initial stage of screwing of the plunger rod 20 and the gasket 30, the rotational force in the screwing direction applied to the plunger rod 20 can be reduced, and the screwing operation can be facilitated.

  Further, the protrusions 22 and 224 may be provided only at the intermediate portion in the protruding direction (axial direction) of the columnar portion 22 of the plunger rod 20. In this case, while making the screwing operation easy at the initial stage of screwing of the plunger rod 20 and the gasket 30, the protrusions 24 and 224 are bitten into a portion where the gasket 30 has high rigidity and is difficult to be deformed, thereby suppressing high loosening. An effect can be obtained.

  Further, for example, as in Modification 2 shown in FIGS. 8 to 11, two protrusions 124 (slack suppression portions) are provided at intervals in the muscle direction on the mountain portion of the male screw portion 23 of the plunger rod 20. May be. These protrusions 124 are located in the middle part of the columnar portion 22 in the protruding direction. The protrusion 124 is gradually lowered in the rotation direction when screwing, and the tip end portion 124 a in the rotation direction is formed so as to be smoothly connected to the crest portion of the male screw portion 23. Further, the base end portion 124b of the protrusion 124 protrudes in a step shape with respect to the peak portion, and is sharp.

  On the inner surface of the cylindrical portion 31 of the gasket 30 of the second modification, as shown in FIGS. 10 and 11, two concave portions 35 having a shape into which the projection 124 is fitted are formed at the same interval as the projection 124. Yes. The concave portion 35 is positioned so that the protrusion 124 fits when the male screw portion 23 is completely screwed into the female screw portion 33. Corresponding to the shape of the protrusion 124, the depth of the concave portion 35 is shallow on the side corresponding to the distal end portion 124 a of the concave portion 35 and gradually becomes deeper toward the side corresponding to the base end portion 124 b of the concave portion 35. Therefore, when the male screw portion 23 is completely screwed into the female screw portion 33, the two protrusions 124 are securely fitted into the corresponding concave portions 34, thereby preventing the male screw portion 23 and the female screw portion 33 from loosening. it can. In the second modification, the concave portion 35 also constitutes a loosening suppression portion. The number of the protrusions 124 may be one or three or more, and the protrusion 124 may be provided on the distal end side of the columnar portion 22 or on the proximal end side. It may be provided. The recess 35 may be provided in accordance with the number and position of the protrusions 124.

  Further, although not shown in the drawings, the female screw portion 33 of the gasket 30 is provided with a protrusion (loosening suppressing portion) protruding inward of the cylindrical portion 31, and the male screw portion 23 is screwed into the female screw portion 33. Sometimes, the protrusion may be pressed against the female screw portion 23 of the plunger rod 20 to prevent loosening of the male screw portion 23 and the female screw portion 33.

  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. The side view of the front end side of a plunger rod is shown. It is the figure which looked at the plunger rod from the front end side. It is a fragmentary sectional view which expands and shows the state which couple | bonded the plunger rod and the gasket. FIG. 5 is a diagram corresponding to FIG. 4 according to Modification 1 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. It is sectional drawing of the gasket which concerns on the modification 2 of embodiment. It is the XI-XI sectional view taken on the line in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Prefilled syringe 20 Plunger rod 22 Columnar part 23 Male thread part (1st thread part)
24 Protrusion (Looseness suppression part)
30 Gasket 31 Tubular part 32 Bottom wall part 33 Female thread part (second thread part)

Claims (11)

It is a coupling structure of a plunger rod having a columnar part protruding from a tip part and a gasket having a cylindrical part into which the columnar part is inserted,
A first screw part is provided on the outer peripheral surface of the columnar part,
On the inner peripheral surface of the cylindrical portion, a second screw portion that is screwed to the first screw portion is provided,
At least one of the first screw portion and the second screw portion is provided with a looseness suppressing portion that suppresses loosening of the first screw portion and the second screw portion in a screwed state. The combined structure of plunger rod and gasket.   2. The plunger rod-gasket coupling structure according to claim 1, wherein the looseness suppressing portion includes a protrusion formed on the first screw portion of the plunger rod.   3. The plunger rod / gasket coupling structure according to claim 2, wherein a plurality of protrusions are formed on a peak portion of the first screw portion.   3. The coupling structure of the plunger rod and gasket according to claim 2, wherein a plurality of protrusions are formed in a valley portion of the first screw portion.   5. The plunger rod and gasket coupling structure according to claim 2, wherein the protrusion is formed in a saw blade shape.   6. The projection according to claim 2, wherein the protrusion is formed so as to be gradually lowered in a rotation direction when the first screw portion and the second screw portion are screwed together. Structure of the plunger rod and gasket as described.   7. The plunger rod / gasket coupling structure according to claim 2, wherein the protrusion is formed over the entire muscle direction of the first screw portion.   The plunger rod and gasket coupling structure according to any one of claims 2 to 7, wherein a concave portion into which the protrusion is fitted is formed in the cylindrical portion of the gasket.   9. The plunger rod / gasket coupling structure according to claim 2, wherein the protrusion is provided at an intermediate portion in the protruding direction of the columnar portion.   The plunger rod and gasket according to any one of claims 1 to 9, wherein the plunger rod and the gasket are used for a prefilled syringe in which a liquid medicine is prefilled in a syringe body. And the combined structure.   The syringe provided with the coupling structure of the plunger rod and gasket of Claim 1-10.

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