US Patent 7811261 Needle cover assembly for a syringe

A single-use cover assembly that obscures a substantial majority or an entirety of an injection needle from view before, during, and after an injection procedure. The cover assembly includes a housing and a needle sleeve that retracts and extends by sliding axially within the housing. The needle sleeve carries a locking collar that moves from a first position to a second position once the needle sleeve is fully retracted. In the first position the locking collar allows retraction of the needle sleeve from a fully extended position. In the second position, a portion of the locking collar covers a tip of the needle, thereby preventing retraction of the needle sleeve from the fully extended position.