Patent ID: 8438705

Claim:
A double layer zipper, comprising: two zipper tapes, an interlocking series of teeth at each of opposing top and bottom sides of each of said two zipper tapes, each said interlocking series of teeth comprising a left-handed or right-handed series of coils, each said coil comprising a coil head and a coil body connected to a front side of said coil head, and a zipper slider coupled to the interlocking series of teeth at said two zipper tapes and movable to open/close the interlocking series of teeth at said two zipper tapes, said zipper slider comprising opposing top guard frame wall and bottom guard frame wall, a division wall vertically connected between said top guard frame wall and said bottom guard frame wall and a nose located on a top side of said top guard frame wall; wherein: said coil body comprises a recessed face disposed adjacent to the associating coil head, two flank portions disposed at two opposite lateral sides of said recessed face, and a neck connected between said recessed face and associating coil head so that each said coil has a tadpole-shaped profile; each said zipper tape comprises a seal strip covered on transverse top and bottom edges and one longitudinal side edge thereof and stitched with the associating interlocking series of teeth; said zipper slider further comprises two openings respectively cut through said top guard frame wall and said bottom guard frame wall, a plurality of pivot holes respectively formed in said top guard frame wall and said bottom guard frame wall and kept in communication with said openings at two opposite lateral sides, and a plurality of rollers respectively symmetrically accommodated in said openings pivotally coupled to said pivot holes in said top guard frame wall and said bottom guard frame wall.