a needle assembly with a needle holder , a needle sleeve movable over the needle holder , and an interlocking member . the needle sleeve encloses a needle holder and is manually extendable and retractable in a telescopic manner to enclose or expose respectively the distal sharp portion of a needle without the aid of a spring or spring - like device . in this assembly , the needle attached to a connector is embedded into the needle holder to prevent movement of the needle during use . temporary locking and release means are provided which are simple and inexpensive in design .