Patent ID: 7425205
Filing Date: 2008-09-16
Classification: A61M

Abstract:
1. A disposable syringe comprising: a needle cannula; a tubular needle seat including a front hub portion which is disposed to fix said needle cannula therein, a gripped portion which extends from said front hub portion in a longitudinal direction, and a rear anchoring portion which is disposed opposite to said front hub portion in the longitudinal direction; a barrel having an inner surrounding barrel surface which surrounds an axis in the longitudinal direction and which defines a passage therein, said passage having rearward and forward openings which are disposed opposite to each other in the longitudinal direction, said inner surrounding barrel surface including a larger-diameter portion and a smaller-diameter portion which are disposed proximate to said rearward and forward openings, respectively, said larger-diameter portion having a retaining area which is spaced apart from said smaller-diameter portion in the longitudinal direction, said smaller-diameter portion including a retaining region which is disposed proximate to said larger-diameter portion and which is configured to retain said front hub portion thereat when said needle seat is in a position of use, and a friction diminishing region which extends from said retaining region toward said forward opening and which terminates at a shoulder abutment, said shoulder abutment defining a communicating hole which permits passage of said needle cannula therethrough, and being spaced apart from said front hub portion along the axis in the position of use; a tubular grip member which, in the position of use, is disposed to bring said gripped portion into engagement with said retaining area by virtue of a first frictional force generated therebetween; a tubular plunger which is disposed to be movable in said passage along said larger-diameter portion, said plunger having a front opened end wall which is movable to abut against said grip member, a rear opened end wall which is disposed opposite to said front opened end wall and which extends outwardly of said rearward opening so as to be manually operable, and an intermediate surrounding wall which is interposed between said front and rear opened end walls and which defines an accommodation chamber; a coupling member having a surrounding retained portion which surrounds the axis and which is disposed in said accommodation chamber to be in frictional engagement with said intermediate surrounding wall by virtue of a second frictional force, and an anchored portion which is disposed adjacent to said front opened end wall in the position of user which confronts said rear anchoring portion, and which is engageable with said rear anchoring portion by a holding force when said coupling member is moved forwardly towards said forward opening such that, when said grip member is pushed forward by virtue of forward movement of said plunger against the first frictional force to cause said front hub portion to move past said friction diminishing region to abut against said shoulder abutment, a pushing force subsequently applied to said plunger causes said anchored portion to rub against said rear anchoring portion, which remains unmoved in place due to engagement of said front hub portion with said shoulder abutment, so that said anchored portion is engaged with said rear anchoring portion and is moved relative to said intermediate surrounding wall towards said rear opened end wall so as to release said surrounding retained portion from said intermediate surrounding wall, thereby enabling said anchored portion to be moved from the position of use to a retracted position where said anchored portion is disposed closer to said rear opened end wall and where said needle seat and said needle cannula are received in said accommodation chamber; and a biasing member disposed to bias said anchored portion towards the retracted position.