Needle assembly

摘要

A needle assembly 1 includes a hub 4 retaining a cannula 3, a protective unit 5 advancing and retracting to surround the forward end of the cannula 3, and a cylindrical portion 6 surrounding the outer periphery of the protective unit 5; the protective unit 5 has a construction in which a protective cover 7 protruding from and retracting into the cylindrical portion 6 is formed integrally with a spring portion 8 so as to be in series therewith, with the hub 4 and the cylindrical portion 6 being coupled together to form a hub member.

主权项

1. A needle assembly comprising: a hub retaining a cannula; a protective cover advancing and retracting with respect to the hub to be situated at an advanced position where it surrounds a forward end of the cannula and a retracted position where it exposes the forward end of the cannula; an urging means elastically provided between the hub and the protective cover and forwardly urging the protective cover; and a stopper means retaining the protective cover at the advanced position,
the protective cover capable of being moved into a pre-use state in which the protective cover is situated at the advanced position to surround the forward end of the cannula, a use state in which the protective cover is situated at the retracted position to expose the forward end of the cannula, and a post-use state in which the protective cover is situated again at the advanced position to surround the forward end of the cannula and fixed in position so as not to be allowed to move to the retracted position again, the hub being provided with a cylindrical portion surrounding an outer periphery of the protective cover, one of a hub member formed by the hub and the cylindrical member and the protective cover being provided with an engagement protrusion, the other being provided with a guide means for regulating movement of the engagement protrusion, the guide means being provided with a pre-use retaining portion which retains the engagement protrusion at the position of the pre-use state and a post-use retaining portion for fixing the engagement protrusion at the position of the post-use state such that, when the protective cover is caused to retract against the urging force of the urging means from the pre-use state, the protective cover retracts to be placed in the use state, and when the protective cover is caused to advance from the use state, the engagement protrusion is fixed to the post-use retaining portion to be placed in the post-use state, and a step portion is provided on a path through which the engagement protrusion moves from the pre-use retaining portion to the post-use retaining portion such that when the protective cover moves from the pre-use state to the use state, if the engagement protrusion moves over the step portion, movement of the engagement protrusion toward the pre-use retaining portion side is regulated by the step portion wherein a return prevention protrusion protruding on an inner peripheral surface side is formed adjacent to the step portion, wherein a return prevention protrusion protruding on an inner peripheral surface side is formed adjacent to the step portion.