| 主权项 |
1. A syringe barrel comprising:
an barrel main body having a cylinder tip at a distal end of the barrel main body; and a cap detachably attached to the cylinder tip by threaded engagement to seal an opening of the cylinder tip, wherein the cylinder tip comprises at least one projection that projects radially from an outer periphery of a proximal end part of the cylinder tip, wherein the cap includes a cylindrical cover that covers an outer periphery of the cylinder tip, wherein a proximal-side inner periphery of the cover comprises a reduced radius portion, and, when the cap is threadedly engaged with the cylinder tip, a distance from a rotation axis of the cap to the reduced radius portion is smaller than a distance from the rotation axis to an outer end of the at least one projection, wherein a portion of the proximal-side inner periphery of the cover is expanded outwardly by the at least one projection, which deforms another portion of the proximal-side inner periphery inwardly, thereby forming the reduced radius portion, and wherein the reduced radius portion is engaged with the at least one projection to prevent loosening of the cap when the cap is attached to the cylinder tip. |
