JP2011115446A - Connecting structure of plunger rod with gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To visually check a coupling state of a plunger rod and a gasket while satisfying both ease of coupling of a gasket and a plunger rod at the time of manufacturing a prefilled syringe and difficulty of coming off during manufacturing and transportation. The purpose is to confirm with.
In a coupling structure in which a plunger rod having a first screw provided at a tip and a gasket having a second screw formed on the inner periphery thereof are coupled by screwing of the first screw and the second screw. A convex portion is provided on one of the base end of the gasket and the top surface of the plunger rod, and a concave portion into which the convex portion can be inserted is provided on the other side. A coupling structure characterized in that a restraining portion that suppresses relative rotation in the loosening direction of the screwing is provided, and at least a part of the concave portion and the convex portion are provided on the outer surfaces of the plunger rod and the gasket.
[Selection] Figure 2

Description

  The present invention relates to a plunger rod and gasket detachment preventing mechanism, and more particularly to a plunger rod and gasket detachment preventing mechanism of a prefilled syringe filled with a chemical solution.

  In the manufacture of a syringe filled with a chemical solution, that is, a prefilled syringe, the barrel is usually filled with the chemical solution, and the plunger rod is bonded to the gasket after the gasket is plugged. That is, a method in which a plunger rod is coupled to a syringe with a gasket plugged as a subsequent process is employed. This is because the stoppering process becomes difficult if a plunger rod is previously attached to the gasket. And, as a method of connecting the gasket of the syringe and the plunger rod, the method of connecting the gasket and the plunger rod as in a normal syringe is mated, and when the plunger rod is press-fitted into the gasket, the gasket moves in the radial direction. Since it is difficult to spread, there is a possibility that the chemical solution leaks from the tip nozzle by the pressure. Therefore, as a method of joining the gasket of the prefilled syringe and the plunger rod, the internal thread of the gasket formed of a rubber elastic material such as butyl rubber or elastomer and the male screw of the plunger rod formed of plastic such as polypropylene are screwed. The method of combining is widely adopted.

  However, the conventional coupling by screwing may be loosened due to a difference in the size of screws at the time of manufacture or an error in tightening torque of the assembly machine. In this case, for example, there is a possibility that the screw may be rotated and detached due to vibration of the vehicle during transportation or the like, or that the plunger rod may be dropped during manufacture.

  In view of this, there is known one in which the plunger rod is prevented from falling off by preventing the gasket and the plunger rod from rotating in the opposite directions (see Patent Document 1). In Patent Document 1, a prefilled syringe includes a plunger rod having a top surface provided with a male screw, a gasket provided with a female screw that is screwed with the male screw, and projects from the top surface of the plunger rod in the distal direction. A convex portion is provided, and a concave portion that engages with the convex portion is provided at the tip of the gasket.

JP 2005-80957 A

  However, in the invention described in Patent Document 1, a convex portion that protrudes in the distal direction is provided on the top surface of the plunger rod, and the gasket is also provided with a concave portion that engages with the convex portion at the distal end of the female screw. Although it is difficult to come off when screwed, when the screwing is completed, the coupling state of the concave portion and the convex portion cannot be visually confirmed, and there is a possibility that a defect may occur during assembly.

  The present invention is capable of visually confirming the coupling state of the plunger rod and the gasket while achieving both ease of coupling of the gasket and the plunger rod during manufacture of the prefilled syringe and difficulty of coming off during production and transportation. Objective.

According to the first aspect of the present invention, a plunger rod provided with a first screw on the outer periphery of a columnar portion provided so as to protrude from the top surface, and a second screw threadedly engaged with the first screw are formed on the inner periphery. In the coupling structure in which the gasket is coupled by screwing the first screw and the second screw,
A convex portion is provided on one of the base end of the gasket and the top surface of the plunger rod, and a concave portion into which the convex portion can be inserted is provided on the other.
The convex portion is provided with a suppressing portion that suppresses relative rotation in the loosening direction of the screwing of the gasket and the plunger rod,
At least a part of the concave portion and the convex portion is provided on the outer surface of the plunger rod and the gasket, and is provided with a coupling structure of the plunger rod and the gasket.

  According to a second aspect of the present invention, there is provided a structure in which a plurality of the concave portions and the convex portions are provided, and a coupling structure of the plunger rod and the gasket according to the first aspect is provided.

  According to a third aspect of the present invention, there is provided the plunger rod and gasket coupling structure according to any one of the first and second aspects, wherein the convex portion is tapered in the rotational direction. It is the composition which is done.

  According to a fourth aspect of the present invention, when the concave portion is provided with an engaging portion that is erected perpendicular to a plane including the top surface, and the plunger rod and the gasket are in an engaged state, The engagement portion and the restraining portion are in contact with each other, wherein the plunger rod and gasket coupling structure according to any one of claims 1 to 3 is provided.

  According to the first aspect of the present invention, the plunger rod and the gasket can be easily assembled, and at the same time, the two can be prevented from inadvertently loosening due to vibration or impact, and the coupling state of the gasket and the plunger rod can be visually checked. Because it can be confirmed by, there will be no defects during assembly.

  According to the second aspect of the present invention, since there are a plurality of concave portions and convex portions, the connection between the plunger rod and the gasket can be further strengthened, and further visual confirmation is facilitated.

  According to the invention of claim 3, loosening can be more effectively prevented with a simple configuration.

  According to the invention of claim 4, the combined state of the plunger rod and the gasket can be further strengthened.

(This embodiment)
FIGS. 1-6 is the example which applied the coupling structure of the plunger rod and gasket in connection with this embodiment of this invention to the prefilled syringe. This embodiment will be described with reference to FIGS.

  As shown in FIG. 1, the prefilled syringe 10 includes a syringe body 11 that is formed in a cylindrical shape and is prefilled with a chemical solution 12. A nozzle portion 13 is provided at the distal end of the syringe body 11 and is sealed with a cap 14. On the rear end side of the syringe main body 11, a gasket 30 for sealing the chemical liquid 12 is provided. Then, from the state shown in FIG. 1, the plunger rod 20 is screwed into the gasket 30 so that the gasket 30 and the plunger rod 20 are coupled.

  The prefilled syringe 10 is carried and stored in a state where the plunger rod 20 and the gasket 30 are coupled. The plunger rod 20 and the gasket 30 are not disconnected from each other even when there is vibration or impact during carrying.

FIG. 2 is a perspective view showing a state before the plunger rod 20 and the gasket 30 are joined. This detailed structure will be described with reference to FIGS.
<Gasket>
As shown in FIG. 3, the gasket 30 includes a cylindrical main body 31 and a bottom surface portion 32. A female thread 33 is formed on the inner periphery of the cylindrical main body 31, and a ring portion 34 is provided on the outer periphery thereof for contacting and sealing the inner peripheral surface 11 a of the syringe main body 11 of the prefilled syringe 10. Furthermore, the convex part 35 is provided in the outer surface of the base end (end part of the cylindrical main body 31 in the direction opposite to the bottom face part 32) of the gasket 30. The convex portion 35 includes an inclined surface 36 that gradually decreases in the screw tightening rotation direction, and includes an elevation surface portion 37 in a direction opposite to the screw tightening rotation direction. When the vertical surface portion 37 attempts to rotate in the direction in which the plunger rod 20 is loosened, it serves as a stopper function that suppresses rotation. Further, the number of the convex portions 35 was four as shown in FIG. 5 is a view of the gasket 30 as viewed from the arrow A in FIG.
<Plunger rod>
As shown in FIG. 3, the plunger rod 20 is provided with a columnar portion 22 protruding from the top surface 21 of the plunger rod 20. A male screw 23 is provided on the outer peripheral surface of the columnar portion 22. The male screw 23 is screwed into the female screw 33 of the gasket 30. Here, a cutout 24 (concave portion) is provided on the outer surface of the top surface 21. In this embodiment, the notch 24 has a trapezoidal shape as shown in FIG. 6, and an engaging portion 25 is provided in a part of the notch so as to stand perpendicular to a plane including the top surface 21. It has been. Further, the number of the notches 24 is four, which is the same number as the convex portions 35 of the gasket, and these are also arranged at equal intervals. FIG. 6 is a view of the plunger rod 20 as viewed from the arrow B in FIG.
<Coupled state>
As shown in FIG. 4, the convex portion 35 of the gasket 30 and the notch 24 of the plunger rod 20 are coupled to prevent relative rotation in the direction in which the screwing of the male screw 23 and the female screw 33 is released. It has become.

  A combined state of the plunger rod 20 and the gasket 30 will be described. The columnar portion 22 is pushed into the gasket 30 while rotating the plunger rod 20 from the state shown in FIG. 3 to the state shown in FIG. Then, by rotating and pushing the plunger rod 20, the male screw 23 of the plunger rod 20 is screwed into the female screw 33 of the gasket 30, and the plunger rod 20 and the gasket 30 are coupled. At the end of the coupling operation, the convex portion 35 of the gasket 30 is relatively inserted into the notch 24 of the plunger rod 20. During this operation, the top surface 21 of the plunger rod 20 rotates while being gradually elastically deformed by pressing the inclined surface 36 while contacting the inclined surface 36 of the convex portion 35 of the gasket 30. Then, when the relative rotation is performed until the convex portion 35 is positioned in the notch 24, the inclined surface 36 of the gasket 30 returns to the original shape, and the convex portion 35 and the notch 24 are coupled.

  Therefore, when the tip of the convex portion 35 of the gasket 30 enters the notch 24 of the plunger rod 20, the reverse rotation is prevented, so that the loosening can be easily and reliably prevented. Moreover, since the notch 24 of the plunger rod and the convex portion 35 of the gasket are provided on the outer surface in the coupled state, the coupled state can be easily confirmed visually.

  In the present embodiment, since the assembly is performed as described above, even if a reverse rotational force acts on the plunger rod 20 due to vibration or the like, the elevation surface portion 37 provided on the convex portion 35 of the gasket 30 is It abuts on the engaging portion 25 constituting the notch 24 and cannot be rotated any further. Accordingly, it is possible to prevent the plunger rod 20 from being carelessly detached from the gasket 30 due to vibration during transportation or storage.

  Here, in the coupled state in which the plunger rod 20 and the gasket 30 are coupled, if the upright portion 37 is erected perpendicular to the plane including the top surface 21, the coupled state can be maintained firmly.

  In particular, in the present embodiment, the notch 24 is provided on the top surface 21 of the plunger rod 20, and the convex portion 35 of the gasket 30 enters the notch 24, so that the length of the syringe is not increased. A loosening prevention mechanism can be provided.

  In this embodiment, the gasket is provided with a convex portion and the plunger rod is provided with a notch (concave portion). However, the gasket may be provided with a concave portion and the plunger rod may be provided with a convex portion. Also, when there are a plurality of recesses and protrusions, the plunger rod and gasket can be connected more firmly, and it is easier to check visually. There can be other numbers.

  Further, the number of notches 24 of the plunger rod 20 may be equal to or more than the number of the convex portions 35 of the gasket 30. Also, the shape of the notch need not be substantially trapezoidal, and any shape can be used as long as the convex portion 35 of the gasket 30 fits in.

  Also, the male screw of the plunger rod and the female screw of the gasket may be reversed.

  The present invention is applied to a medical prefilled syringe containing a chemical solution.

It is a figure which concerns on this embodiment of this invention and shows the state before the assembly of a gasket and a plunger rod. It is a perspective view which concerns on this embodiment of this invention and shows the state before the assembly of a gasket and a plunger rod. It is the elements on larger scale of FIG. It is a figure which shows the state which assembled the gasket and the plunger rod in FIG. The top view of a gasket is shown. The top view of a plunger rod is shown.

10 Prefilled syringe 20 Plunger rod 21 Top surface 22 Column-shaped portion 23 Male screw 24 Notch (recessed portion)
25 Projection part 30 Gasket 33 Female thread 35 Convex part 36 Inclined surface 37 Elevated part (suppressing part)

Claims (4)

A plunger rod having a first screw provided on the outer periphery of a columnar portion protruding from the top surface, and a gasket having a second screw threadedly engaged with the first screw formed on the inner periphery. In the coupling structure coupled by screwing the screw and the second screw,
A convex portion is provided on one of the base end of the gasket and the top surface of the plunger rod, and a concave portion into which the convex portion can be inserted is provided on the other.
The convex portion is provided with a suppressing portion that suppresses relative rotation in the loosening direction of the screwing of the gasket and the plunger rod,
At least a part of the concave portion and the convex portion is provided on the outer surfaces of the plunger rod and the gasket, and the plunger rod and gasket coupling structure.   2. The plunger rod and gasket coupling structure according to claim 1, wherein a plurality of the recesses and projections are provided.   The plunger rod and gasket coupling structure according to claim 1, wherein the convex portion has a structure that tapers in a rotational direction.   The concave portion is provided with an engaging portion that is erected perpendicular to a plane including the top surface. When the plunger rod and the gasket are in an engaged state, the engaging portion and the suppressing portion are The joint structure of a plunger rod and a gasket according to any one of claims 1 to 3, wherein the structure is in contact.

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