Abstract: A syringe includes a gasket, a barrel, and a plunger. The plunger includes a helical rib provided at a head portion, and the gasket includes a threaded engagement portion configured to threadedly engaged with the helical rib, a plunger-retaining annular rib, and an accommodation portion for accommodating a part of the plunger at which the helical rib is formed. The annular rib includes a rib absent portion for guiding, to the accommodation portion, the helical rib reaching the annular rib. The gasket further includes an intermediate annular rib provided at a part on a proximal side of the retaining annular rib and a part defined on a side of the distal end of the helical projection, between a distal side annular rib and a proximal side annular rib.

Abstract: A plunger for a syringe that includes a barrel includes: a gasket mounting portion located at a distal end of the plunger; a disk positioned at a proximal end of the gasket mounting portion; a shaft extending proximally from the disk, wherein the shaft comprises a plurality of slats extending proximally from the disk; a pressing portion located at a lower end of the shaft; and a plunger inclination-prevention unit that is located at a distal end of the shaft and is configured to inhibit the plunger from inclining inside the barrel of the syringe. The plunger inclination-prevention unit comprises one or more axially inclined plates, each having a first end disposed on the disk, extending obliquely proximal with respect to a central axis of the shaft, and having a second end disposed on one of the slats.

Abstract: A syringe includes a gasket, a barrel, and a plunger. The plunger includes a helical rib provided at a head portion, and the gasket includes a threaded engagement portion configured to threadedly engaged with the helical rib, a plunger-retaining annular rib, and an accommodation portion for accommodating a part of the plunger at which the helical rib is formed. The annular rib includes a rib absent portion for guiding, to the accommodation portion, the helical rib reaching the annular rib. The gasket further includes an intermediate annular rib provided at a part on a proximal side of the retaining annular rib and a part defined on a side of the distal end of the helical projection, between a distal side annular rib and a proximal side annular rib.

Abstract: A syringe includes a gasket, a barrel, and a plunger. The plunger includes a helical rib provided at a head portion, and the gasket includes a threaded engagement portion configured to threadedly engaged with the helical rib, a plunger-retaining annular rib, and an accommodation portion for accommodating a part of the plunger at which the helical rib is formed. The annular rib includes a rib absent portion for guiding, to the accommodation portion, the helical rib reaching the annular rib. The gasket further includes an intermediate annular rib provided at a part on a proximal side of the retaining annular rib and a part defined on a side of the distal end of the helical projection, between a distal side annular rib and a proximal side annular rib.

Abstract: A syringe includes a gasket, a barrel, and a plunger. The plunger includes a helical rib provided on an outer surface of a head portion, and the gasket comprises a helical valley portion for threadedly engaging with the helical rib, a plunger-retaining annular rib, and an accommodation portion for a part of the plunger at which the helical rib is formed. The annular rib comprises a rib absent portion for guiding, to the accommodation portion, the helical rib reaching the annular rib as threaded engagement is advanced between the plunger and the gasket. The helical rib comprises an entrance-restricting terminal end portion for restricting the entrance of the helical rib into the rib absent portion after the part of the plunger 4 at which the helical rib is formed is stored in the accommodation portion 32 of the gasket.

Abstract: A plunger for a syringe that includes a barrel includes: a gasket mounting portion located at a distal end of the plunger; a disk positioned at a proximal end of the gasket mounting portion; a shaft extending proximally from the disk, wherein the shaft comprises a plurality of slats extending proximally from the disk; a pressing portion located at a lower end of the shaft; and a plunger inclination-prevention unit that is located at a distal end of the shaft and is configured to inhibit the plunger from inclining inside the barrel of the syringe. The plunger inclination-prevention unit comprises one or more axially inclined plates, each having a first end disposed on the disk, extending obliquely proximal with respect to a central axis of the shaft, and having a second end disposed on one of the slats.

Abstract: A syringe includes a gasket, a barrel, and a plunger. The plunger includes a helical rib provided on an outer surface of a head portion, and the gasket comprises a helical valley portion for threadedly engaging with the helical rib, a plunger-retaining annular rib, and an accommodation portion for a part of the plunger at which the helical rib is formed. The annular rib comprises a rib absent portion for guiding, to the accommodation portion, the helical rib reaching the annular rib as threaded engagement is advanced between the plunger and the gasket. The helical rib comprises an entrance-restricting terminal end portion for restricting the entrance of the helical rib into the rib absent portion after the part of the plunger 4 at which the helical rib is formed is stored in the accommodation portion 32 of the gasket.

Abstract: A syringe includes a gasket, a barrel, and a plunger. The plunger includes a helical rib provided at a head portion, and the gasket includes a threaded engagement portion configured to threadedly engaged with the helical rib, a plunger-retaining annular rib, and an accommodation portion for accommodating a part of the plunger at which the helical rib is formed. The annular rib includes a rib absent portion for guiding, to the accommodation portion, the helical rib reaching the annular rib. The gasket further includes an intermediate annular rib provided at a part on a proximal side of the retaining annular rib and a part defined on a side of the distal end of the helical projection, between a distal side annular rib and a proximal side annular rib.