JP5645046B2 - Syringe - Google Patents

Description

  The present invention relates to a syringe for screwing a plunger rod to the piston in use, and more particularly to the syringe capable of preventing excessive screwing when the plunger rod is screwed to the piston.

  As shown in FIG. 11A, conventionally, in a prefilled type syringe 9 with a syringe needle, a syringe 91 is prefilled with a drug solution M, and the drug solution M is sealed by a piston 92. The piston 92 and the plunger rod 93 are configured as separate bodies. When used, the piston 92 and the plunger rod 93 are formed in the hole 921 on the rear end side of the piston 92, so that the screw FS is attached to the base 931 on the front end side of the plunger rod 93. The formed male screw MS is screwed to integrate both.

  As shown in FIG. 11B, the height H of the male screw MS is larger than the depth D of the hole 921 in which the female screw FS is formed, or as shown in FIG. Is equal to the depth D of the hole 921 in which the female screw FS is formed.

  In the case of FIG. 11B (when the height H of the external thread MS is larger than the depth D of the hole 921 in which the female thread FS is formed), as shown in FIG. Is completed (that is, even if the tip of the male screw MS reaches the bottom surface of the hole 921), a gap K is generated between the surface of the base 931 and the rear end surface of the piston 92. The operator (doctor / nurse, etc.) may determine that the screwing is not completed because of the gap K, and the tendency to screw the plunger rod 93 into the piston 92 excessively increases.

  If this screwing is performed excessively, the thread of the external thread MS tries to get over the thread of the female thread FS, and as a result, the piston 92 tends to bulge in the radial direction as shown in FIG. For this reason, there exists a problem that the piston 92 cannot perform a smooth operation | movement with the force p which presses the wall surface of the syringe 91. FIG.

  In the case of FIG. 11C (when the height H of the external thread MS is the same as the depth D of the hole 921 in which the female thread FS is formed), when the screwing is completed, the base 931 is provided. There is no gap between the surface of the piston 92 and the rear end surface of the piston 92. Since the operator (doctor, nurse, etc.) determines whether or not the screwing is completed based on the rotational resistance of the screw and the presence / absence of the gap, it is unlikely that the plunger rod 93 is excessively screwed into the piston 92. However, it is generally difficult to stably produce a product made of an elastic material such as a rubber piston with high accuracy. Therefore, the gap K may be generated between the surface of the base 931 and the rear end surface of the piston 92 even when the screwing is completed, as in the case of FIG.

  The present invention has been proposed in order to solve the above-described problems, and in a syringe for screwing a plunger rod into a piston in use, it is possible to prevent excessive screwing during the screwing. An object of the present invention is to provide such a syringe.

The gist of the syringe of the present invention is (1) to (3).
(1) A syringe for screwing a plunger rod into a piston in use,
The piston is provided with a female screw hole from the rear end surface side,
A male screw whose height is lower than the depth of the female screw hole is erected on the column end or the disk base at the tip of the plunger rod,
Upon the screwing, when said column end and said disc base of the tip of the rear end face side to the plunger rod of the piston is in contact with screwed state, the bottom surface and the external thread of the female screw hole between the tip, to lower the 1/12 without a thread pitch p of the previous SL male thread 1/8, the upper limit is 3/7 to 1/2 of the gap of the maximum thread pitch p is formed,
A syringe characterized by that.

  In the present invention, when the operator screws the plunger rod into the piston, the first operation resistance is felt when the rear end surface side of the piston comes into contact with the column end or the disk base at the tip of the plunger rod. . At this point, there is a gap between the bottom of the female screw hole and the tip of the male screw, but if the operator further advances the screwing, before the threads of the female screw and the female screw hole completely climb, The tip of the male screw reaches the bottom surface of the female screw hole, thereby feeling the second operation resistance.

If δ is too small, it becomes impossible to distinguish the resistance between the first operating resistance and the second operating resistance.
When δ is too large, the threads of the male screw and the female screw hole are completely laid over each other. As a result, the force pressing the wall surface of the syringe increases, and the sliding resistance of the piston increases.
If the magnitude of δ is appropriate, the first operating resistance and the second operating resistance can be distinguished, and the ridges do not run completely, so when the screwing operation is stopped, the male screw and female screw The riding state between the screw threads of the holes returns so as to approach the original state.

That is, the lower limit of the size of the gap formed between the bottom surface of the female screw hole and the tip of the male screw is a size that can distinguish the resistance between the first operating resistance and the second operating resistance. The pitch is preferably 1/12 to 1/8 of the pitch. In addition, the upper limit of the size of the gap formed between the bottom of the female screw hole and the tip of the male screw is such that the threads of the male screw and the female screw hole do not completely run over each other, and the thread pitch 1/2 to 3/8 of the above).
(2) The diameter of the rear end of the piston is smaller than the diameter of the column end or the diameter of the disc base, and the column end or the disc base is flat. The syringe according to (1).

(3) A diameter of a rear end portion of the piston is formed smaller than a diameter of the column end or a diameter of the disk base, and the rear end of the piston is arranged around the column end or the disk base. The syringe according to (1), wherein a wall for preventing the end portion from bulging in the radial direction is provided upright.

  Because of this wall, when the plunger rod is excessively screwed into the piston, the rear end portion of the piston is compressed, and even if the rear end portion swells radially, the bulge is suppressed. The resistance for the plunger rod to get over the internal thread of the piston increases, and excessive screwing is suppressed.

  In the syringe of the present invention, when the operator feels the initial operating resistance, it can be visually observed that there is no gap between them, so that excessive screwing is prevented when the plunger rod is screwed to the piston. In addition, even when the operator proceeds further screwing without noticing the initial operation resistance, the second operation resistance is generated, so that excessive screwing is prevented.

FIG. 1 is an explanatory view showing an example of a syringe to which the present invention is applied. It is explanatory drawing which shows 1st Embodiment of this invention, (A) is explanatory drawing which shows the plunger rod and piston of a syringe, (B) is AA sectional drawing of (A). It is a figure which shows the effect | action of 1st Embodiment, (A) is a figure which shows the relationship between the height of the external thread of a plunger rod, and the depth of the internal thread hole of a piston, (B) is a bottom face of an internal thread hole. The figure which shows a mode that the space | gap was formed between the front-end | tip of a male screw, and (C) are figures which show a mode that a piston produces a distortion | strain as the thread of a male thread tries to get over the thread of a female thread. It is explanatory drawing which shows 2nd Embodiment of this invention, (A) is explanatory drawing which shows the plunger rod and piston of a syringe, (B) is AA sectional drawing of (A). It is explanatory drawing which shows 3rd Embodiment of this invention, (A) is explanatory drawing which shows the plunger rod and piston of a syringe, (B) is AA sectional drawing of (A). It is a perspective view which shows the disk base which the wall in which the notch part used in 3rd Embodiment is formed standingly arranged. It is a figure which shows the effect | action of 3rd Embodiment, (A) is a figure which shows the relationship between the height of the external thread of a plunger rod, and the depth of the internal thread hole of a piston, (B) is a bottom face of an internal thread hole. The figure which shows a mode that the space | gap was formed between the front-end | tip of a male screw, and (C) are figures which show a mode that a piston produces a distortion | strain as the thread of a male thread tries to get over the thread of a female thread. It is explanatory drawing which shows 4th Embodiment of this invention, (A) is explanatory drawing which shows the plunger rod and piston of a syringe, (B) is AA sectional drawing of (A). It is a perspective view which shows the disk base with which the wall used by 4th Embodiment stood. It is a figure which shows the effect | action of 4th Embodiment, (A) is a figure which shows the relationship between the height of the external thread of a plunger rod, and the depth of the internal thread hole of a piston, (B) is a bottom face of an internal thread hole. The figure which shows a mode that the space | gap was formed between the front-end | tip of a male screw, and (C) are figures which show a mode that a piston produces a distortion | strain as the thread of a male thread tries to get over the thread of a female thread. (A) is a view showing a conventional prefilled type syringe, (B) is a view showing a case where the height of the male screw is larger than the depth of the hole in which the female screw is formed, and (C) is a view showing the height H of the male screw MS. It is a figure which shows the case where it is the same as the depth of the hole in which the screw was formed. (A) The figure which shows a mode that a clearance gap arises between the surface of a base, and the rear-end surface of a piston, (B) is that a piston tries to bulge to radial direction by excessive screwing, and a piston presses against the wall surface of a syringe. It is a figure which shows a mode.

  The present invention is applied to a syringe in which a plunger rod is screwed to a piston when used, and the screwed state can be visually observed.

  FIG. 1 is an explanatory view showing an example of a syringe to which the present invention is applied, and is a view showing a configuration example of a prefilled type syringe. In the syringe 1 of FIG. 1, the drug solution M is sealed in the syringe 13 by a piston 12 (in the following embodiments, the rear end portion of the piston 12 is slightly recessed). A cap 15 is attached to the injection needle attachment portion 131 at the tip of the syringe 13. In use, the cap 15 is removed, the injection needle 14 is attached, and the plunger rod 11 is screwed into the piston 12.

  The plunger rod 11 is made of polyethylene, polypropylene, radiation resistant polypropylene or the like. The piston 12 is molded from synthetic rubber (or an appropriate thermoplastic elastomer) whose surface is laminated with a synthetic resin (fluorine polymer (PTFE, ETFE) or the like).

2A and 2B are explanatory views showing the first embodiment of the present invention, where FIG. 2A is an explanatory view showing the plunger rod 11 and the piston 12 of the syringe, and FIG. It is AA sectional drawing.
A flat disk base 111 is formed at the tip of the plunger rod 11, and a male screw 112 is erected on the disk base 111. The (longitudinal portion 113) of the plunger rod 11 is composed of four plate-like ribs whose cross section forms a cross as a whole (see FIG. 2B), and an operation flange is provided at the rear end of the plunger rod 11. 114 is formed. The piston 12 is formed with a female screw hole 121 from the rear end face side. The diameter of the rear end portion of the piston 12 is smaller than the diameter of the disc base 111.

FIG. 3A is a diagram showing the relationship between the height MH of the male thread 112 of the plunger rod 11 and the depth FD of the female thread hole 121 of the piston 12. The height MH of the external thread 112 is formed lower than the depth FD of the female thread hole 121 of the piston 12. In FIG. 3A, the difference between the depth FD and the height MH is indicated by δ (= FD−MH).
That is, when the plunger rod 11 is screwed into the piston 12, the rear end surface side of the piston 12 and the disc base at the tip of the plunger rod 11 come into contact with each other. At this time, as shown in FIG. A gap CB (height δ) is formed between the bottom surface of the female screw hole 121 and the tip of the male screw 112.

When the operator screws the plunger rod 11 into the piston 12, the rear end surface side of the piston 12 comes into contact with the disc base at the tip of the plunger rod 11. At this time, the load when the plunger rod 11 is screwed into the piston 12 increases rapidly, and the operator feels an operation resistance (hereinafter referred to as “first operation resistance”).
At this time, the operator can feel that the screwing of the plunger rod 11 and the piston 12 is completed. Usually, it is visually confirmed that there is no gap between the front end of the plunger rod 11 and the rear end of the piston 12, and the screwing operation is terminated.
However, for example, when the syringe is very small or when the injection is urgent, the operator cannot recognize the primary operation resistance despite the primary operation resistance ( You may not feel it).
Further, even if the operator feels the primary operation resistance, the screwing operation may be continued for further confirmation.

As the screwing progresses, as shown in FIG. 3C, the thread of the external thread 112 tries to get over the thread of the internal thread 122, and the piston 12 is distorted. In this embodiment, since the distortion (deformation) generated in the piston 12 is absorbed by the gap CB, the expansion of the piston 12 in the radial direction can be reduced (or prevented), and the piston 12 becomes difficult to slide. Such inconvenience does not occur. In many cases, the operator ends the screwing operation at this point.
Furthermore, the operator may continue screwing. In this case, the leading end of the external screw 112 reaches the bottom surface of the female screw hole 121. As a result, the operator feels an operation resistance (hereinafter referred to as “secondary operation resistance”), so he is convinced that the screwing is completed and ends the screwing operation.

If δ is too small, the time interval between the primary operating resistance and the secondary operating resistance is shortened, making it impossible to distinguish them.
If δ is too large, the threads of the male screw MS and the female screw FS are completely laid on each other. As a result, the force for pressing the wall surface of the syringe increases, and the sliding resistance of the piston increases.
If the magnitude of δ is appropriate, the first operating resistance and the second operating resistance can be distinguished, and the mountains do not run completely. The riding state of the threads of the screw FS returns so as to approach the original state.
That is, the lower limit of δ is such that the resistance between the first operating resistance and the second operating resistance can be distinguished, and is preferably 1/12 to 1/8 of the thread pitch p. The upper limit of δ is such that the threads of the male screw and the female screw hole do not completely run over each other, and is about 1/2 to 3/8 of the thread pitch p (specifically, 2/5, 4/9, 3/7, 2/5, etc.).
In addition, although the case where the bottom face of the internal thread hole 121 and the front-end | tip of the external thread 112 were flat was demonstrated, these surfaces can be comprised in a curved surface.

4 (A) and 4 (B) are explanatory views showing a second embodiment of the present invention, (A) is an explanatory view showing a plunger rod 11 and a piston 12 of a syringe, and (B) is (A). It is AA sectional drawing.
In the second embodiment, the diameter of the rear end portion of the piston is smaller than that of the first embodiment, and the same portion forms a larger gap between the syringe inner wall and the first embodiment of FIG. The configuration is almost the same. FIG. 4 shows an example in which the plunger rod 11 is formed of a cylinder having a flat column end. However, FIG. 4 shows another example of the form of the plunger rod, and the first embodiment of FIG. Even if it replaces with the plunger rod shown to the form, it does not affect the effect of this invention. Moreover, in 2nd Embodiment, the effect | action and effect at the time of screwing the plunger rod 11 and piston 12 are the same as 1st Embodiment. That is, the operator feels the primary operation resistance according to the screwing, and at this time, it can be visually confirmed that there is no gap between the front end of the plunger rod 11 and the rear end of the piston 12.

Therefore, excessive screwing does not occur. Further, even if the operator continues the screwing and the thread of the external thread 112 tries to get over the thread of the internal thread 122 and the piston 12 is distorted, the strain is reduced on the rear end side of the piston. Is absorbed in the gap between the piston and the inner wall of the syringe and the gap CB, so that there is no inconvenience that the piston 12 becomes difficult to slide.
Furthermore, when the screwing operation is continued, secondary operation resistance is generated, so that excessive screwing can be reliably prevented.

FIGS. 5A and 5B are explanatory views showing a third embodiment of the present invention, where FIG. 5A is an explanatory view showing a plunger rod 11 and a piston 12 of a syringe, and FIG. It is AA sectional drawing.
As will be described later, the third embodiment has substantially the same configuration as the second embodiment of FIG. 4 except that a wall WLa having a cutout portion CT is provided around the disc base (111a). is there. That is, as shown in FIGS. 5A and 5B, a disc base 111a provided with a wall WLa having a notch portion CT is formed at the tip of the plunger rod 11, and the disc base is formed. A male screw 112 is erected on the base 111a. The (longitudinal portion 113) of the plunger rod 11 is composed of four plate-like ribs whose cross section forms a cross as a whole, and an operation flange 114 is formed at the rear end of the plunger rod 11. The piston 12 is formed with a female screw hole 121 from the rear end face side.

  In 3rd Embodiment, the disk base 111a by which the wall WL for preventing the swelling of the rear-end part of the piston 21 to radial direction was standingly formed in the front-end | tip of the plunger rod 11 is formed. . As shown in the perspective view of FIG. 6, the disc base 111a has four notches CT formed in the wall WL. In the present embodiment, the notches CT have a central angle of 45 ° and are formed at four locations on the wall WLa at 90 ° intervals.

  As shown in FIG. 7A, in this embodiment, the diameter D2 of the rear end portion of the piston 12 is formed smaller than the diameter D1 of the disc base 111a. Further, similarly to the first embodiment, the height MH of the external thread 112 is formed lower than the depth FD of the female thread hole 121 of the piston 12. The difference between the depth FD of the internal thread 121 and the height MH of the external thread 112 is indicated by δ (= FD−MH).

  When the plunger rod 11 is screwed into the piston 12, the rear end face side of the piston 12 and the disc base at the tip of the plunger rod 11 come into contact with each other. At this time, as in the case of the first embodiment, FIG. As shown in (B), a gap (height δ) is formed between the bottom surface of the female screw hole 121 and the tip of the male screw 112.

  Also in this embodiment, the lower limit of δ is such that the resistance between the first operating resistance and the second operating resistance can be distinguished, and is preferably 1/12 to 1/8 of the thread pitch p. The upper limit of δ is such that the threads of the male screw and the female screw hole do not completely run over each other, and is about 1/2 to 3/8 of the thread pitch p (specifically, 2/5, 4/9, 3/7, 2/5, etc.). When the operator screws the plunger rod 11 into the piston 12, the operator feels the primary operation resistance when the rear end surface side of the piston 12 comes into contact with the disk base at the tip of the plunger rod 11. At this point, the operator can feel that the plunger rod 11 and the piston 12 have been screwed together. Usually, the front end of the plunger rod 11 and the rear end of the piston 12 It is confirmed by visually checking the notch portion CT formed in the wall WL that there is no gap in the space S, and the screwing operation is finished.

Even if the operator feels the primary operation resistance, if the screwing operation is continued for further confirmation, as shown in FIG. 7C, the thread of the male screw 112 is changed to the screw thread of the female screw 122. As a result, the piston 12 is distorted. In the present embodiment, even if distortion (deformation) that occurs in the piston 12 occurs, it is absorbed by the gap CB, and the bulging of the rear end of the piston 12 in the radial direction is prevented by the wall WLa. Therefore, there is no inconvenience that the piston 12 becomes difficult to slide. Further, since the bulging is prevented, the screwing resistance after the primary operation resistance is increased, and the operator feels the primary operation resistance more strongly. In many cases, the operator ends the screwing operation at this point.
Further, when the operator continues the screwing operation, the leading end of the male screw 112 reaches the bottom surface of the female screw hole 121. Thereby, since the operator feels the secondary operation resistance, he is sure that the screwing is completed and ends the screwing operation.

8A and 8B are explanatory views showing a fourth embodiment of the present invention, where FIG. 8A is an explanatory view showing a plunger rod 11 and a piston 12 of a syringe, and FIG. It is AA sectional drawing.
In this embodiment, instead of the disk base 111a with the wall WLa having the notch CT used in the syringe of the third embodiment, the wall WLb without the notch is erected. The disc base 111b is used. FIG. 9 shows a perspective view of the disk base 111b used in the present embodiment.

FIG. 10A shows the relationship between the height MH of the male screw 112 formed on the disc base 111 b at the tip of the plunger rod 11 and the screw hole 121 formed on the female screw 122.
When the plunger rod 11 is screwed into the piston 12, the rear end surface side of the piston 12 comes into contact with the disk base at the tip of the plunger rod 11. At this time, a gap (height δ) is formed between the bottom surface of the female screw hole 121 and the tip of the male screw 112 as shown in FIG.

  Also in this embodiment, the lower limit of δ is such that the resistance between the first operating resistance and the second operating resistance can be distinguished, and is preferably 1/12 to 1/8 of the thread pitch p. The upper limit of δ is such that the threads of the male screw and the female screw hole do not completely run over each other, and is about 1/2 to 3/8 of the thread pitch p (specifically, 2/5, 4/9, 3/7, 2/5, etc.). When the operator screws the plunger rod 11 into the piston 12, the operator feels the primary operation resistance when the rear end surface side of the piston 12 comes into contact with the disk base at the tip of the plunger rod 11. Then, at this point, the operator can feel that the screwing of the plunger rod 11 and the piston 12 will be completed.

Even if the operator feels the primary operation resistance, if the screwing operation is continued for further confirmation, as shown in FIG. 10C, the thread of the male screw 112 is changed to the screw thread of the female screw 122. As a result, the piston 12 is distorted.
Even in this embodiment, as in the third embodiment, even if distortion (deformation) generated in the piston 12 occurs, it is absorbed by the gap CB, and the bulging in the radial direction of the rear end of the piston 12 is caused by the wall WL. Be blocked. Therefore, there is no inconvenience that the piston 12 becomes difficult to slide. Further, since the bulging is prevented, the screwing resistance after the primary operation resistance is increased, and the operator feels the primary operation resistance more strongly. In many cases, the operator ends the screwing operation at this point.
Further, when the operator continues the screwing operation, the leading end of the male screw 112 reaches the bottom surface of the female screw hole 121. Thereby, since the operator feels the secondary operation resistance, he is sure that the screwing is completed and ends the screwing operation.

DESCRIPTION OF SYMBOLS 1 Syringe 11 Plunger rod 12 Piston 13 Syringe 14 Injection needle 15 Cap 111 Disc base 111a Disc base provided with the wall which has a notch part 111b Disc provided with the wall which does not have a notch part Base 112 Male thread 113 Longitudinal part 114 Operation flange 121 Female thread hole 131 Injection needle mounting part CB Cavity CT Notch part M Chemical solution WLa Wall with notch part WLb Wall without notch part

Claims (3)

A syringe for screwing a plunger rod into a piston in use,
The piston is provided with a female screw hole from the rear end surface side,
A male screw whose height is lower than the depth of the female screw hole is erected on the column end or the disk base at the tip of the plunger rod,
At the time of the screwing, when the rear end surface side of the piston and the column end or the disk base at the tip of the plunger rod come into contact with each other in the screwed state, the bottom surface of the female screw hole and the male screw Between the tip, a gap having a lower limit of 1/12 to 1/8 of the thread pitch p of the male screw and an upper limit of 3/7 to 1/2 of the maximum thread pitch p is formed.
A syringe characterized by that. A diameter of a rear end portion of the piston is formed smaller than a diameter of the column end or a diameter of the disc base, and a gap is provided between the rear end portion of the piston and a syringe inner wall. The syringe according to claim 1.   A diameter of a rear end portion of the piston is formed smaller than a diameter of the column end or the diameter of the disk base, and the periphery of the column end or the disk base has a rear end portion of the piston. The syringe according to claim 1, wherein a wall for preventing bulging in the radial direction is provided upright.

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