Hypodermic syringe needle guard

A needle guard for a hypodermic syringe comprising a flexible membrane which is shaped to define a toroidal chamber which, under a first pressure, is conical in shape and includes one end portion having an opening means sized for passage of the needle, an other end portion sized for attachment to a forward portion of a barrel of the hypodermic syringe, and a length to extend beyond the tip of the needle, the membrane further shaped so that the toroidal chamber extends around the needle when the needle guard is attached to the hypodermic syringe whereby the needle does not extend into the toroidal chamber, and which, when closed and under a second pressure less than said first pressure, is foldable inwardly upon itself so that the needle passes within said opening means and beyond the membrane for use thereof, means for attachment of said other end portion to the forward portion of the barrel of the hypodermic syringe, and means for applying said first pressure to said chamber to effect unfolding of the membrane to cover the needle tip for preventing needle-stick or re-use of a used hypodermic needle.

A needle guard for a hypodermic syringe comprising a flexible membrane which is shaped to define a toroidal chamber which, under atmospheric pressure, is conical in shape and includes one end portion having an opening means sized for passage of the needle, an other end portion sized for attachment to a forward portion of a barrel of the hypodermic syringe, and a length to extend beyond the tip of the needle, the membrane further shaped so that the toroidal chamber extends around the needle when the needle guard is attached to the hypodermic syringe whereby the needle does not extend into the toroidal chamber, said membrane chamber being closed and at least partially evacuated and folded inwardly upon itself so that the needle passes within said opening means and beyond the membrane, means for attachment of said other end portion to the forward portion of the barrel of the hypodermic syringe, and means for applying a first pressure to said chamber to effect unfolding of the membrane to cover the needle tip for preventing needle-stick or re-use of a used hypodermic needle.

In combination with a hypodermic syringe including a barrel having a forward portion and a needle attached to said forward portion, a needle guard comprising a flexible membrane which is shaped to define a toroidal chamber which includes one end portion having an opening means sized for passage of the needle and includes an other end portion attached to said forward portion of said barrel of the hypodermic syringe and which, under a first pressure, is conical in shape and extends beyond the tip of the needle, the toroidal chamber extending around the needle whereby the needle does not extend into the toroidal chamber, and which, when closed and under a second pressure less than said first pressure, is foldable inwardly upon itself so that the needle passes within said opening means and beyond the membrane for use thereof, and means for applying said first pressure to said chamber to effect unfolding of the membrane to cover the needle tip for preventing needle-stick or re-use of a used hypodermic needle.