Abstract: A disposable hypodermic syringe, which is provided with the needle fitted and sheathed, provides automatic retraction of the needle after use. The syringe may be supplied pre-charged with an injectant. The completion of the injection stroke attaches the piston to the needle carrier and subsequently dislodges a retaining ring thereby freeing the piston from the plunger and releasing stored energy of a spring or the like to draw the piston and needle carrier into the plunger. The plunger is positively retained inside the housing by the interaction of rings. Alternative methods of locating the needle carrier during use and of attaching the piston to the needle carrier to enable retraction are shown. An alternative method of retaining the piston on the plunger is also shown. A further configuration is shown affording the use of an offset needle. The syringe has optional features to prevent unwanted inward movement of the plunger and to prevent seepage of liquid after use.

Abstract: A hypodermic syringe includes a housing (1), a plunger (2) with an associated piston (3), a needle carrier (4) with a needle (5) covered by a removable sheath (6). A vacuum is formed between the plunger (2) and piston (3). When the plunger (2) is operated, the piston (3) engages the needle carrier and a coupling between the plunger and piston is broken, so that the vacuum withdraws the piston (3) into the plunger (2), together with the needle carrier, so as to retract the needle into the housing (1). The needle carrier (4) is rectangular in cross-section and is received in a corresponding rectangular sectioned housing opening (1.2) in order to prevent rotation of the needle carrier relative to the housing. This facilitates removal of the needle sheath, without the risk of a needle stick injury prior to use of the syringe, and allows for the separate and external fitting of a needle.

Abstract: A rotary actuator for a valve is associated with an indicator mechanism provided entirely exteriorily to the housing of the valve and out of axial alignment with the valve spindle. The indicator rotates with an actuating member of the valve and is movable relative to a surface of the actuating member to provide a visual and tactile indication of the operative position of the valve.