Face mask for dust and filter protection - has filter element formed by successive folding of sheet with nose clip and head band

摘要

The filter element is formed by folding a rectangular sheet of suitable material. This is first folded in half about its minor axis. Each opposite side is then folded into the centre, from its corner, to provide a triangular overlap (14,15). The lower edges (18,19) are folded, the top one over and up to produce a double thickness and the lower one similarly over and under. All thicknesses are stitched and the element opened out to form a cup fitting over the nose and mouth; a nose clip and head band is also provided.