Non-reusable syringe

A syringe device comprising:

• a generally elongate hollow body slidably containing a plunger end of a plunger in fluid sealing relationship therewith, the hollow body having a first end with a fluid inlet/outlet, and a second end opposite to the first end;
• the plunger further comprising an elongate plunger rod having one end thereof attached to the plunger end and the other end thereof projecting out from the second end of the hollow body for slidably moving the plunger end along and within the hollow body;
• a guide means formed in, and being integral with, the plunger rod and which extends along the plunger rod;
• and
• a locking member which is received in and guided by the guide means, which has at least one snag projection facing in a direction away from the first end of the body and towards the inside surface of the body, and which is in frictional sliding engagement with the inside surface of the body so as to provide for relative movement of the locking member with respect to the guide means;
• wherein the guide means has a first stop means against which the locking member bears during the first intake stroke;
• a second stop means spaced from said first stop means and against which the locking member bears during the delivery stroke;
• a slide means extending between the first and second stop means along which the locking member slides during use of the syringe device;
• wherein the first stop means causes the locking member to be orientated at a first angle with respect to a longitudinal axis of the plunger rod wherein the snag projection is spaced from the inside surface of the body, the second stop means causes the locking member to be orientated at a second angle with respect to the longitudinal axis which is greater than said first angle, and wherein the snag projection is still spaced from the inside surface of the body, and
• wherein the guide means further comprises an interference portion which, during a second intake stroke, causes the locking member to pivot further away from the longitudinal axis and thereby snaggingly engage the snag projection against the inside surface of the body to resist further movement of the plunger in the intake stroke direction, but only when the locking member is oriented at least a predetermined angle with respect to the longitudinal axis which is larger than the first angle at the commencement of the second intake stroke.

A syringe device comprising:

• a generally elongate hollow body slidably containing a plunger end of a plunger in fluid sealing relationship therewith, the hollow body having a first end with a fluid inlet/outlet, and a second end opposite the first end;
• the plunger further comprising an elongate plunger rod having one end thereof attached to the plunger end and with the other end thereof projecting out from the second end of the hollow body for slidably moving the plunger end along within the hollow body;
• a guide means formed in, and being integral with, the plunger rod and which extends along the plunger rod;
• and
• a locking member which is received in and guided by the guide means, which as at least one snag projection facing in a direction away from the first end of the body and towards the inside surface of the body, and which is in frictional sliding engagement with the inside surface of the body so as to provide for relative movement of the locking member with respect to the guide means;
• wherein the guide means comprises:
• an elongate slide means extending longitudinally of the plunger rod;
• a first stop means at one end of the slide means;
• a contoured portion at a predetermined position along the slide means;
• and
• a second stop means at the other end of the slide means;
• the device further comprising a sleeve member which cooperates with the plunger rod, whereby, in use, the sleeve member overhangs and retains the locking member adjacent the first stop means during the first intake stroke, the locking member bears against the first stop means during the delivery stroke whilst the sleeve member is caused to move relative to the plunger rod away from the guide means and release the locking member;
• and, at the commencement of the second intake stroke, the locking member is caused to slide along the slide means such that a portion thereof rides up an inclined face of the contoured portion and is caused to pivot with respect to the longitudinal axis of the plunger rod (and brings) whereby the snag projection is brought into snagging engagement with the inside surface of the hollow body to resist further movement of the plunger in the intake stroke direction.

A syringe device comprising:

• a generally elongate hollow body slidably containing a plunger end of a plunger in fluid sealing relationship therewith, the hollow body having a first end with a fluid inlet/outlet, and a second end opposite to the first end;
• the plunger further comprising an elongate plunger rod attached at one end thereof to the plunger end and with the other end thereof projecting out from the second end of the hollow body for slidably moving the plunger end along and within the hollow body;
• a guide means formed in, and being integral with, the plunger rod;
• and
• a locking member which is received in and guided by the guide means, which has at least one snag projection facing in a direction away from the first end of the body and towards the inside surface of the body, and which is in frictional sliding engagement with the inside surface of the body so as to provide for relative movement of the locking member with respect to the guide means;
• wherein the plunger rod is formed by a first member and a second member which cooperate and, in combination, define the guide means for receiving and guiding the locking member, wherein:
• the plunger rod members are slidable with respect to one another in the longitudinal direction of the plunger rod between a retracted position and an extended position;
• the first plunger member has an overhand portion and the second plunger member has a contoured portion, with the first and second plunger members, in combination, forming an elongate slide means;
• the locking member has a hook portion at one end thereof which is closest to the first end of the body, a base portion spaced from the hook portion, with the snag projection being at the other end of the locking member opposite to the one end;
• and
• wherein, in use, the first and second plunger members are initially in the retracted position with the locking member wedged between the overhang portion and the slide means and the hook portion;
• whereby, during a first intake stroke, the contoured portion moves towards, under and past the hook portion of the locking member whilst the plunger rod members move to their extended position;
• and, during a subsequent delivery stroke, the contoured portion moves back towards the hook portion and an edge of the contoured portion is engaged with the hook portion whereafter the locking member is caused to be disengaged from between the overhang portion and the slide means and is moved forwards towards the plunger end along the slide means whilst the plunger members move back towards their retracted position;
• and, during a second intake stroke, the contoured portion moves rearwardly relative to the locking member and causes the base portion of the locking member to ride up an inclined surface of the contoured portion so that the snag projection snaggingly engages with the inside surface of the hollow body whereby the plunger is prevented from further movement in the intake stroke direction.