A self-destroying hypodermic syringe

Claim 2

A self-destroying hypodermic syringe of the dispos­able kind, comprising a cylinder (1) which has a cannula (2) provided at one end, with a plunger (3) and a plunger rod (4) provided in the cylinder, and with a breaking means (6) associated with plunger or plunger rod to be broken after the first use of the syringe, characterized in that breaking means (6) consists of a member (10) with at least one cam follower (13) cooperating with a cam or coulisse (14) in another member (15), which cam or coulisse extends obliquely in relation to the syringe axis and which cam or coulisse (14) at one end join an axially extending cam or coulisse (16) which opens towards one end of member (15), that a stop (17) for the cam follower (13) is provided at the end of cam (14) opposite its joint with coulisse (16).

Claim 3

A hypodermic syringe as defined in claim l, characterized in that the cam follower (13) or cam followers are arranged on a member (10) which is attached to the plunger rod, via said turnable member (7), and that member (15) with cam or coulisse (14) is attached to the plunger.

Claim 4

A hypodermic syringe as defined in claim 1 or 2, characterized in that the cam or coulisse consists of the edge or side of an oblique groove (14) in the surface of a cylindrical member (15) which is attached to the top of the plunger.

Claim 5

A self-destroying hypodermic syringe of the dispos­able kind, comprising a cylinder (1) which has a cannula (2) at one cnd, with a plunger (3) and a plunger rod (4) provided in the cylinder, and with a breaking means (6) associated with plunger or plunger rod, to be broken after the first use of the syringe, characterized in that there are two cam followers (13) facing each other and each being provided at the end of one of two arms (11) projecting axially from member (10), that member (15) consists of a cylindrical body (15) which is integrated with plunger (3), that the oblique groove (14) extends from the plunger from the port­ion of body (15) facing away from plunger (3), that the oblique groove (14) at the end closest to the plunger joins a second oppositely directed oblique groove (20) which at its end far from the plunger joins a further oblique groove (21) extending in the same direction as the first groove (14), that oblique groove (20) at its end facing the plunger joins a groove (22) which opens towards the free edge of cylindrical body (15), that the first oblique groove (14) where it joins the second groove (20) has less depth than the latter, that groove (20) where it joins groove (21) has less depth than the latter, and that groove (21) where it joins groove (22) has less depth than the latter so that each groove (14, 20, 21) passes into the subsequent groove across a step.

Claim 6

A self-destroying hypodermic syringe of the dispos­able kind, comprising a cylinder (1) which has a cannula (2) at one cnd, with a plunger (3) and a plunger rod (4) provided in the cylinder, and with a breaking means (6) associated with plunger or plunger rod, to be broken after the first use of the syringe, characterized in that there are two cam followers (13) facing each other and each being provided at the end of one of two arms (11) projecting axially from member (10), that member (15) consists of a cylindrical body (15) which is integrated with plunger (3), that the oblique groove (14) extends from the plunger from the port­ion of body (15) facing away from plunger (3), that the oblique groove (14) at the end closest to the plunger joins a second oppositely directed oblique groove (20) which at its end far from the plunger joins a further oblique groove (21) extending in the same direction as the first groove (14), that oblique groove (20) at its end facing the plunger joins a groove (22) which opens towards the free edge of cylindrical body (15), that the first oblique groove (14) where it joins the second groove (20) has less depth than the latter, that groove (20) where it joins groove (21) has less depth than the latter, and that groove (21) where it joins groove (22) has less depth than the latter so that each groove (14, 20, 21) passes into the subsequent groove across a step.

Claim 7

A hypodermic syringe as defined in one or several of the preceding claims, characterized in that there is such friction between cam follower (13) and cam (14) that the syringe may be ventilated and activated without the cam follower moving along the cam.

Claim 8

A self-destroying hypodermic syringe as defined in claim 4, characterized in that grooves (14, 20, 21) have a decreasing depth towards their subsequent groove.

Claim 9

A self-destroying hypodermic syringe as defined in claim 4 or 6, characterized in that grooves (14, 20, 21, 22) form a zig-zag pattern on the sur­face of body (15).

Claim 10

A self-destroying hypodermic syringe as defined in claim 7, characterized in that groove (14) in one zig-zag pattern joins groove (22) which is open to­wards the end of body (15) in the other zig-zag pattern closely to the open end of the latter.

Claim 11

A self-destroying hypodermic syringe as defined in claim (8), characterized in that a boss or a transverse cam is arranged in the bottom of the grooves at the joining point of groove (14) and groove (22) in the second zig-zag pattern.

Claim 12

A self-destroying hypodermic syringe as defined in claims 4 and 9, characterized in that the two arms (11) which carry the cam followers (13) are manufact­ured from a resilient material, so that the cam followers when introduced into one groove (22) each which open towards the end of body (15) may be displaced from said groove into the oblique groove (14) of the second zig-zag pattern by an axially rotating movement of a certain force.

Claim 13

A self-destroying hypodermic syringe, as defined in claim 1, characterized in that a freely turnable member is provided in connection with the plunger rod or between the latter and the plunger.