Disposable, safe butterfly needle sheath

A needle sheath assembly comprising:

• a cap;
• a wing unit including a hollow cylinder and two wings at both sides of the cylinder;
• a barrel unit including a hollow barrel, a hollow, cylindrical extension at a forward end of the barrel, the extension being adapted to insert through the cylinder into the cap for coupling, and a T-shaped slot longitudinally formed on an outer surface of the barrel, a transverse bar of the slot including a bridge at a junction of a right portion thereof and a right opening;
• and
• a needle unit including a hollow plunger, a forward needle, two opposite latched members raised above an edge of a rear end, and a protrusion projected from an outer surface of the plunger wherein the protrusion is projected from the slot after inserting the needle unit in the barrel unit,
• whereby removing the cap and sliding the protrusion from the transverse bar of the slot to a distal end of the slot will project the needle from the cylinder;
• and sliding the protrusion from the distal end of the slot to the right opening through the bridge will lock the protrusion in the right opening.