Gasket and syringe

Patent metadata

Field	Value
Publication number	US-9415169-B2
Application number	US-201013255289-A
Country	US
Kind code	B2
Filing date	Feb 23, 2010
Priority date	Mar 9, 2009
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

A gasket configured so that a pusher having a male screw thread on the outer periphery of its tip is connected to the gasket through the male screw thread and so that the gasket slides within a syringe outer tube when the pusher is operated in the longitudinal direction. The gasket includes: a gasket body having a hollow section and a female screw thread in the inner peripheral section of the hollow section engaged by the male screw thread; and projections on the outer peripheral section of the gasket body extending circumferentially of the outer peripheral section and axially arranged in spaced relation to each other. When the gasket is not yet inserted into the syringe outer tube, a screw thread located in a portion on the inner side of and in direct proximity to the projection has a smaller height than a screw thread located in the remaining portion.

First claim

The invention claimed is:

1. A gasket which is connected to a pusher having a male screw formed on an outer peripheral portion of a distal end thereof, by screw engagement with the male screw of the pusher, the gasket being slid within a syringe outer tube by operation of the pusher in longitudinal directions thereof, the gasket comprising:
a gasket body having a hollow section and a female screw formed on an inner peripheral portion of the hollow section, the female screw being screw-engaged with the male screw; and
a plurality of projections which are projectingly formed on an outer peripheral portion of the gasket body so as to extend in a circumferential direction of the outer peripheral portion and which are arranged so as to be spaced from each other along an axial direction of the gasket body,
wherein in an uninserted state in which the gasket is not yet inserted into the syringe outer tube, a screw thread located at a portion on the inner side of the gasket and in close proximity to each of the projections has a smaller height than a screw thread located at another portion,
wherein, in an inserted state in which the gasket is inserted into the syringe outer tube, each of the projections is pressed by an inner peripheral surface of the syringe outer tube, so that a height difference between the screw threads of the female screw approaches zero, and
wherein, in the inserted state, the gasket is connected to the pusher and a clearance is formed between the female screw and the male screw after the pusher has been inserted into the gasket.

2. The gasket according to claim 1 , wherein the height difference between the screw threads of the female screw in the uninserted state is of 0.08 to 0.30 mm.

3. A syringe provided with the gasket according to claim 2 , wherein the inside diameter of the syringe outer tube is equal to or less than 7 mm.

4. The gasket according to claim 1 , wherein the female screw has a pitch of 1.0 to 4.0 mm.

5. A syringe provided with the gasket according to claim 4 , wherein the inside diameter of the syringe outer tube is equal to or less than 7 mm.

6. The gasket according to claim 1 , wherein in the uninserted state, the outside diameter of a portion of the gasket that has the projection is greater than the inside diameter of the syringe outer tube by 3 to 20%.

7. A syringe provided with the gasket according to claim 6 , wherein the inside diameter of the syringe outer tube is equal to or less than 7 mm.

8. A syringe provided with the gasket according to claim 1 , wherein the inside diameter of the syringe outer tube is equal to or less than 7 mm.

9. The gasket according to claim 1 , wherein the screw thread located at the portion on the inner side of the gasket and in close proximity to each of the projections has a smaller radial dimension from the inner side of the gasket than a screw thread located at another portion, and wherein in the inserted state in which the gasket is inserted into the syringe outer tube, each of the projections is pressed by the inner peripheral surface of the syringe outer tube, so that a difference in the radial dimensions between the screw threads of the female screw approaches zero.

10. A gasket which is connected to a pusher having a male screw formed on an outer peripheral portion of a distal end thereof, by screw engagement with the male screw of the pusher, the gasket being slid within a syringe outer tube by operation of the pusher in longitudinal directions thereof, the gasket comprising:
a gasket body having a hollow section and a female screw formed on an inner peripheral portion of the hollow section, the female screw being screw-engaged with the male screw; and
a plurality of protections which are proiectingly formed on an outer peripheral portion of the gasket body so as to extend in a circumferential direction of the outer peripheral portion and which are arranged so as to be spaced from each other along an axial direction of the gasket body,
wherein in an uninserted state in which the gasket is not yet inserted into the syringe outer tube, a screw thread located at a portion on the inner side of the gasket and in close proximity to each of the protections has a smaller height than a screw thread located at another portion,
wherein, in an inserted state in which the gasket is inserted into the syringe outer tube, each of the projections is pressed by an inner peripheral surface of the syringe outer tube, so that a height difference between the screw threads of the female screw approaches zero, and
wherein in the female screw in the uninserted state, the tooth thickness of the lower screw thread is larger than the tooth thickness of the higher screw thread.

11. A syringe provided with the gasket according to claim 10 , wherein the inside diameter of the syringe outer tube is equal to or less than 7 mm.

Assignees

• Tachikawa Kouichi
• Ogawa Junichi
• Terumo Corp

Inventors

• Tachikawa Kouichi
• Ogawa Junichi

Classifications

• A61M2005/3104

  Caps for syringes without needle · CPC title

• A61M5/31515 Primary

  Connection of piston with piston rod · CPC title