Piston for tapered syringe and syringe thereof

Abstract

To provide a piston capable of reducing sufficiently, an amount of a paste material which is left in a syringe without being discharged from a discharge part, even when being used in a syringe formed into a tapered shape, for enhancing discharge rate of the filled paste material.SOLUTION: In a state of inserting a piston 3 into a syringe, the piston comprises a column part 34a of a hole part and a diameter reduction part 34b on an opening side of the syringe, and the hole part is formed over a discharge part side relative to a contact part of the piston where contacts the syringe.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present invention relates to a piston that pushes out a pasty material filled in a syringe, and to a syringe from which the pasty material filled inside is discharged by the piston. [Background technology]

[0002] In the dental field, paste-like materials such as dental filling materials and materials for making dental crowns are sometimes filled in a container such as a syringe in order to optimize the amount of material discharged. A piston is arranged in the syringe so as to be able to slide inside the syringe, and the paste-like material filled in the syringe is discharged from the nozzle by pressing the piston in the direction of the nozzle as a discharge part with an appropriate tool, for example, an applicator. When such a container is used, there is a problem that a large amount of the paste-like material remains in the syringe without being discharged from the nozzle. JP 2001-353169 A (Patent Publication 1) discloses a conventional piston in which the surface on the nozzle side is made of a deformable material in order to reduce the amount of the paste-like material remaining in the syringe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-353169 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, syringes with a tapered shape have been used to optimize the amount of material discharged from the discharge part of the syringe. However, the conventional piston of Patent Document 1 has a portion that contacts the inner surface of the syringe made of a non-deformable material, so that the range in which the piston can move toward the discharge part is greatly limited in the tapered pistons used in recent years. As a result, a large amount of pasty material remains, particularly near the inner surface of the syringe, and the amount of pasty material that cannot be discharged from the discharge part and remains in the syringe cannot be sufficiently reduced.

[0005] An object of the present invention is to provide a piston that, even when used in a syringe with a tapered shape, can sufficiently reduce the amount of pasty material that cannot be discharged from the discharge part and remains in the syringe, thereby increasing the discharge rate of the filled pasty material. [Means for solving the problem]

[0006] The present invention provides a deformable piston that pushes out a pasty material filled in a syringe from the discharge portion of the syringe, wherein when the piston is inserted into the syringe, the piston has a hole on the opening side of the syringe, and the hole is formed further toward the discharge portion than the contact portion of the piston that contacts the syringe.

[0007] In the piston of the present invention, it is preferable that a tapered portion that becomes narrower toward the discharge portion side than the contact portion is provided on the discharge portion side, and the hole portion is formed up to the tapered portion.

[0008] In the piston of the present invention, the contact portion is preferably formed by the end of the tapered portion on the opening side.

[0009] In the piston of the present invention, it is preferable that a protrusion is formed on the discharge portion side of the tapered portion.

[0010] The piston of the present invention preferably includes a columnar portion located on the opening side of the syringe.

[0011] The present invention also provides a syringe in which a paste-like material filled inside is pushed out from an outlet portion by the piston of the present invention, the syringe having a tapered portion that becomes narrower toward the outlet portion, and a protrusion is provided inside the tapered portion.

[0012] In the syringe of the present invention, it is preferable that the direction in which the pasty material is extruded from the discharge portion is inclined with respect to the opening. Effect of the Invention

[0013] Even when the piston of the present invention is used in a syringe having a tapered shape, it can sufficiently reduce the amount of pasty material that cannot be discharged from the discharge portion and remains in the syringe, thereby increasing the discharge rate of the filled pasty material. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a state in which a piston according to an embodiment of the present invention is inserted into a syringe. [Diagram 2] FIG. 1 is a perspective view of a syringe according to an embodiment; [Diagram 3] FIG. 1 is a front view of a syringe according to an embodiment; [Figure 4] FIG. 1 is a plan view of a syringe according to an embodiment; [Diagram 5] 1 is a bottom view of a syringe according to an embodiment; [Figure 6] FIG. 1 is a longitudinal cross-sectional view of a syringe according to an embodiment; [Figure 7] FIG. 1 is a perspective view of a piston according to an embodiment; [Figure 8] FIG. 1 is a front view of a piston according to an embodiment; [Figure 9] FIG. 1 is a plan view of a piston according to an embodiment; [Figure 10] 1 is a bottom view of a piston according to an embodiment; [Figure 11] FIG. 1 is a longitudinal cross-sectional view of a piston according to an embodiment; [Figure 12]FIG. 2 is a longitudinal section of a piston according to a second embodiment; [Figure 13] FIG. 13 is a perspective view of a piston according to the third embodiment; [Figure 14] 13 is a bottom view of the piston of the third embodiment; [Figure 15] FIG. 13 is a longitudinal section of a piston according to a third embodiment; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a state in which a piston 3 is inserted into a syringe 1 according to one embodiment of the present invention. The piston 3 pushes out a paste material (not shown) filled in the syringe 1 from a discharge part of the syringe 1 (described later). The piston 3 is configured to be deformable. The piston 3 can be integrally formed, for example, from a resin material. Examples of the resin material that can be used include polyethylene, polyacetal, polypropylene, polyamide, vinyl chloride resin, nylon, phenolic resin, polyurethane, saturated polyester resin, melamine resin, polyvinylidene chloride, unsaturated polyester resin, polybutadiene, polystyrene, EVA (ethylene-vinyl acetate copolymer) resin, styrene resin, polymethylpentene, methacrylic styrene, ABS (acrylonitrile, butadiene, styrene) resin, and polycarbonate. The syringe 1 can be integrally formed, for example, from a resin material. The same material as the piston 3 can be used as the resin material.

[0016] 2 to 6 are respectively a perspective view, a front view, a plan view, a bottom view, and a longitudinal sectional view of the syringe 1. FIGS. 7 to 11 are respectively a perspective view, a front view, a plan view, a bottom view, and a longitudinal sectional view of the piston 3. The syringe 1 has a discharge part 11 for discharging the pasty material filled in the syringe 1, and an opening 12 into which the piston 3 is inserted. The piston 3 inserted in the syringe 1 is pressed toward the discharge part 11 by a suitable instrument (not shown), for example, an applicator, and slides toward the discharge part 11 inside the syringe 1. The piston 3 slides toward the discharge part 11, whereby the pasty material filled in the syringe 1 is discharged from the discharge part 11.

[0017] The syringe 1 is composed of a first section S1 having an outlet 11 at one end, a second section S2 having an opening 12 at one end, and a third section S3 located between the first section S1 and the second section S2.

[0018] The first section S1 has a first inner wall surface 14 surrounding a first passage 13 having a circular cross-sectional shape. The first passage 13 is formed so that the size of the cross-section increases with increasing distance from the discharge portion 11. The size of the cross-section of the first passage 13 is smaller than the outline of a contact portion 32 (described later) after the contact portion 32 is deformed toward a hole portion 34 (described later) inside. That is, the first section S1 is a portion into which the contact portion 32 of the piston 3 cannot enter.

[0019] The second section S2 has a second inner wall surface 16 surrounding a second passage 15 having a circular cross-sectional shape. The second passage 15 is formed so that the size of the cross-section is the same as the size of the opening 12. The size of the cross-section of the second passage 15 is formed so that it is the same as or slightly smaller than the contour of the outer circumferential surface of the contact portion 32 of the piston 3. In other words, the second section S2 is a portion where the contact portion 32 can smoothly slide toward the hole portion 34 without being deformed.

[0020] The third section S3 has a third inner wall surface 18 surrounding a third passage 17 that communicates with the first passage 13 and the second passage 15. The third passage 17 is formed so that the size of the cross section increases from the first passage 13 toward the second passage 15. This third section S3 is a portion into which the contact portion 32 can enter by deforming toward the hole portion 34, as described below.

[0021] 1, the boundaries between the first to third sections are indicated by dashed lines. Thus, in syringe 1 of this embodiment, first section S1 and third section S3 form tapered section 19 in which the size of the cross section of the passage surrounded by the inner wall decreases from opening 12 toward discharge section 11.

[0022] The piston 3 of this embodiment includes a columnar portion 31 having a substantially cylindrical shape, an annular contact portion 32, and a tapered portion 33 having a notched cone shape. The columnar portion 31 is located on the opening 12 side of the syringe 1 when the piston 3 is inserted into the syringe 1.

[0023] The contact portion 32 has a size that allows it to come into contact with the first inner wall surface 14 surrounding the first passage 13 without being deformed when the piston 3 slides toward the discharge portion 11 inside the syringe 1. In this embodiment, the contact portion 32 has an outer diameter dimension that is larger than the outer diameter dimension of the columnar portion 31.

[0024] In the columnar part 31, a hole 34 is provided on an end surface 31a on the opening 12 side of the syringe 1 when the piston 3 is inserted into the syringe 1. The hole 34 is formed to the discharge part 11 side of the syringe 1 from the contact part 32 of the piston 3 that contacts the syringe 1. In this embodiment, the hole 34 is formed along the longitudinal direction of the piston 3. By forming such a hole 34, the deformable piston 3 can deform the contact part 32 toward the hole 34 when an external force is applied to the contact part 32 of the piston 3, and the contact part 32 can be made smaller. Therefore, the piston 3 can be slid toward the discharge part 11 side until it enters not only the second passage 15 of the second section S2 where the contact part 32 can smoothly slide without deforming toward the hole 34, but also the third passage 17 of the third section S3 where the contact part 32 can enter by deforming toward the hole 34. Therefore, the amount of the pasty material remaining in syringe 1 without being discharged from discharge portion 11 can be sufficiently reduced, and the discharge rate of the filled pasty material can be increased.

[0025] Here, in a plane perpendicular to the longitudinal direction, the area of ​​the hole 34 (the total value when there are two or more holes) is preferably within a range of 2 to 50% of the area of ​​the contact part 32, and particularly preferably within a range of 3 to 40%. If it is less than 2%, the contact part 32 cannot deform toward the hole 34, and the discharge rate of the filled paste material cannot be increased. If it exceeds 50%, the applicator enters the hole 34, and it becomes complicated to remove the applicator from the piston 3, which increases the treatment time, and the hands of the surgeon may be contaminated when removing the applicator. Furthermore, when the applicator advances through the syringe 1 to the discharge part 11 due to the pressure of the applicator, the contact part 32 may deform too much, causing a backflow of the paste.

[0026] The total length of the piston 3 in the longitudinal direction is preferably 3 to 50 mm, and particularly preferably 5 to 30 mm. If it is less than 3 mm, the piston 3 may be too small and difficult for the surgeon to handle. If it exceeds 50 mm, it may affect treatment in the oral cavity. Furthermore, the amount of paste to be filled increases, which has a large environmental and economic impact.

[0027] The dimension of the hole 34 in the longitudinal direction of the piston 3 is preferably 0.1 to 0.8, and particularly preferably 0.2 to 0.7, assuming that the total length of the piston 3 in the longitudinal direction is 1. If the dimension is less than 0.1, the contact portion 32 cannot deform toward the hole 34, and it may not be possible to increase the discharge rate of the filled pasty material. If the dimension is more than 0.8, the hole may penetrate the piston 3, causing a backflow of the pasty material.

[0028] It is preferable that hole 34 is formed 0.5 mm or more toward discharge part 11 of syringe 1 from contact part 32 of piston 3 that contacts syringe 1. By making it such a size, contact part 32 can be surely deformed toward hole 34.

[0029] In this embodiment, the piston 3 has a tapered portion 33 that becomes narrower toward the discharge portion 11 side on the side closer to the discharge portion 11 than the contact portion 32, and the hole portion 34 is formed up to the tapered portion 33. Therefore, not only the contact portion 32 but also the tapered portion 33 can be deformed toward the hole portion 34, and the discharge rate of the filled pasty material can be further increased.

[0030] Particularly in this embodiment, the hole 34 is formed so that its cross section perpendicular to the longitudinal direction of the piston 3 has a circular shape, and is configured to have a cylindrical portion 34a whose size in cross section is constant, and a tapered portion 34b whose size in cross section decreases with increasing distance from the end face 31a. Therefore, no extremely thin portion is formed between the outer periphery of the tapered portion 33 of the piston 3 and the hole, and the tapered portion 33 does not deform when the piston 3 slides through the second passage 15 of the second section S2, thereby preventing the sliding movement of the piston 3 from being hindered.

[0031] In this embodiment, a protrusion 35 is formed on the discharge portion 11 side of the tapered portion 33. By forming the protrusion 35, the piston 3 can be pushed further into the tip of the syringe 1, and the amount of pasty material remaining in the syringe can be reduced. In addition, when the piston 3 is inserted into the syringe 1, the pasty material is pushed into the inside of the syringe by the protrusion, which can suppress contamination of the operator's hands and shortening of the curing time. In addition, since the pasty material is pushed into the inside of the syringe by the protrusion, adhesion of the pasty material to the operator's hands can be reduced.

[0032] In this embodiment, the raised portion 20 is provided at a position inside the syringe 1 that spans the first section S1 and the third section S3. In this manner, in this embodiment, the raised portion 20 is provided on the inner circumference of the tapered portion 19 of the syringe 1. The raised portion 20 can be formed, for example, by making the thickness of the syringe 1 thicker than other portions. When such a raised portion 20 is provided, the size of the cross section of the passage in the vicinity of the portion where the raised portion 20 is provided is reduced. Therefore, even in the syringe 1 having a tapered shape in which the size of the cross section of the passage surrounded by the inner wall becomes smaller from the opening 12 toward the discharge portion 11, the amount of the pasty material that cannot be discharged from the discharge portion 11 and remains in the syringe 1 can be sufficiently reduced. Note that a pair of raised portions 20 may be provided at opposing positions inside the syringe.

[0033] Particularly, in this embodiment, the syringe 1 is curved as a whole so that the direction in which the pasty material is pushed out from the discharge portion 11 is inclined with respect to the opening 12. A portion (bent portion) having the largest curvature in the curved direction is located in the first section S1, and the raised portion 20 is formed so as to include this bent portion. With this configuration, even when the syringe 1 is curved as a whole, it is possible to sufficiently reduce the amount of pasty material remaining in the syringe 1.

[0034] The hole 34 may have any shape as long as it is formed closer to the discharge portion 11 of the syringe 1 than the contact portion 32, and may have, for example, a pyramid shape such as a triangular pyramid, a cone, or a square pyramid, a truncated shape thereof, a prismatic shape such as a cylinder or a square prism, a spherical shape, or a combination thereof. Fig. 13 shows a piston 3 according to a second embodiment. In the second embodiment, the hole 34 has a cylindrical portion 34c that opens to the end face 31a and has a constant size in cross section, and a spherical portion 34d that is connected to the cylindrical portion 34c.

[0035] A plurality of holes 34 may be provided. FIGS. 13 to 15 are perspective views, bottom views, and cross-sectional views of the piston 3 according to the third embodiment. In the third embodiment, four holes 34 are formed opening to the end surface 31a. The four holes 34 have the same shape. By forming a plurality of holes in this way, the distance between the holes and the outer periphery of the piston 3 can be adjusted without increasing the size of the entire holes (the total size of the holes). Therefore, it is possible to reliably deform the contact portion 32 toward the hole 34 while maintaining the rigidity of the piston 3. In the third embodiment, the four holes 34 have the same shape, but when a plurality of holes are formed, holes of different shapes may be formed. In addition, when a plurality of holes are formed, it is sufficient that at least one hole is formed to the discharge portion 11 side from the contact portion 32 of the piston 3 that contacts the syringe 1. [Industrial Applicability]

[0036] According to the present invention, even when used in a syringe with a tapered shape, the amount of pasty material remaining in the syringe without being able to be discharged from the discharge portion can be sufficiently reduced, thereby increasing the discharge rate of the filled pasty material. [Explanation of symbols]

[0037] 1 syringe 3 Piston 11 Discharge section 12 Opening 13 First Passage 14 First inner wall surface 15 Second Passage 16 Second inner wall surface 17 Third Passage 18 Third Inner Wall 19 Tapered section 20 Ridge 31 Columnar part 31a End face 32 Contact part 33 Tapered section 34 Hole 34a Cylinder section 34b Reduced diameter part 35 Protrusion S1 First Section S2 Second Section S3 Third Section

Claims

1. A set comprising a syringe having a first section having a discharge portion at one end, a second section having an opening at one end, and a third section located between the first and second sections, and a deformable piston for pushing a pasty material filled in the syringe out of the discharge portion of the syringe, a hole is provided in the piston on the opening side of the syringe when the piston is inserted into the syringe, and the hole is formed to the discharge portion side beyond a contact portion of the piston that contacts an inner wall surface of the syringe; The contact portion of the piston has an outer circumferential surface contour larger than a cross-sectional size of the inner wall surface of the syringe and is deformable toward the hole portion; The contour of the outer circumferential surface of the contact portion after deformation toward the hole portion is the contact portion cannot enter the first section; the contact portion can move without deforming the second section; and The contact portion has a size that allows the contact portion to enter the third section by deforming toward the hole portion, The syringe has a tapered portion that narrows toward the discharge portion.

2. the piston includes a tapered portion that is located closer to the discharge portion than the contact portion and that becomes narrower toward the discharge portion, The set of claim 1 , wherein the hole is formed to a taper.

3. The set according to claim 2 , wherein the contact portion is an end of the tapered portion on the opening side.

4. The set according to claim 2 or 3, wherein a protrusion is formed on the discharge portion side of the tapered portion.

5. The set according to claim 1 , wherein the piston comprises a column located on an opening side of the syringe.

6. The set according to any one of claims 1 to 5, wherein a protrusion is provided inside the tapered portion.

7. The set according to claim 6 , wherein a direction in which the pasty material is extruded from the discharge portion is inclined relative to the opening.

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