Shielded hypodermic syringe

Claim 1

A hypodermic syringe comprising: a barrel adapted to contain a substance to be injected; means for mounting a hypodermic needle to the barrel with the needle having a passage extending therethrough and terminating in a point; means for forcing the substance from the barrel through the passage of the needle; a needle guard; means for mounting the guard on the barrel for movement relative to said barrel, said mounting means mounting the guard for movement between an extended position in which the guard obstructs access to the point of the needle and a retracted position in which the guard does not materially obstruct access to the point of the needle, said extended and retracted positions being axially spaced; said mounting means mounting said guard for movement relative to the barrel along first and second paths when the guard is in the retracted and extended positions, respectively, said first and second paths including first and second generally circumferentially extending regions, respectively; first means responsive to movement of said guard along said first path when the guard is in the retracted position for releasably locking the guard in the retracted position; second means responsive to movement of the guard along the second path when the guard is in the extended position to positively lock the guard in the extended position so that the guard cannot be moved to the retracted position in response to axial force on the guard; said mounting means including a track carried by at least one of said guard and said barrel and track-engaging means carried by the other of said guard and said barrel for defining said first and second paths; said guard having an internal sleeve with distal and proximal edges and said track is provided on said sleeve, said track including at least first and second track sections opening at the distal and proximal edges, respectively; and said track-engaging means including first and second track-engaging members mounted on said barrel and adapted to be received in said first and second track sections, respectively.

Claim 8

An apparatus for injecting a substance into a human or animal comprising: a body adapted to have the substance to be injected pass therethrough; means for mounting a needle on the body with the needle having a passage extending therethrough and terminating in a point whereby the substance can pass from the body to and through the passage of the needle; a needle guard; means for mounting the guard on the body for movement relative to said body, said mounting means mounting the guard for movement between an extended position in which the guard obstructs access to the point of the needle and a retracted position in which the guard does not materially obstruct access to the point of the needle, said extended and retracted positions being axially spaced; said mounting means mounting said guard for movement relative to the body along first and second paths when the guard is in the retracted and extended positions, respectively, said first and second paths including first and second generally circumferentially extending regions, respectively; first means responsive to movement of said guard along said first path when the guard is in the retracted position for releasably locking the guard in the retracted position; second means responsive to movement of the guard along the second path when the guard is in the extended position to positively lock the guard in the extended position so that the guard cannot be moved to the retracted position in response to axial force on the guard; said mounting means including means defining a track and track-engaging means cooperable with the track for defining said first and second paths; and said track being on said guard and said track including at least first and second track sections for use in defining said first and second paths and opening at axially spaced locations along the guard.

Claim 9

An apparatus for injecting a substance into a human or animal comprising: a body adapted to have the substance to be injected pass therethrough; means for mounting a needle on the body with the needle having a passage extending therethrough and terminating in a point whereby the substance can pass from the body to and through the passage of the needle; a needle guard; means for mounting the guard on the body for movement relative to said body, said mounting means mounting the guard for movement between an extended position in which the guard obstructs access to the point of the needle and a retracted position in which the guard does not materially obstruct access to the point of the needle, said extended and retracted positions being axially spaced; said mounting means mounting said guard for movement relative to the body along first and second paths when the guard is in the retracted and extended positions, respectively, said first and second paths including first and second generally circumferentially extending regions, respectively; first means responsive to movement of said guard along said first path when the guard is in the retracted position for releasably locking the guard in the retracted position; second means responsive to movement of the guard along the second path when the guard is in the extended position to positively lock the guard in the extended position so that the guard cannot be moved to the retracted position in response to axial force on the guard; said mounting means including means defining a track and track-engaging means cooperable with the track for defining said first and second paths; and said track being on said guard and said track including at least first and second track sections for use in defining said first and second paths and opening at axially spaced locations along the guard.