Foldable zipper slider with compression-type latch

A foldable plastic slider for straddling relation with a profiled plastic reclosable fastener particularly suited for thermoplastic bags and the like formed by a pair of flexible plastic sheets having a top edge with separable fastener means extending along the length thereof comprising reclosable interlocking male and female elements having rib and groove profiles on the respective sheets, the straddling slider for closing or opening the reclosable fastener elements comprising a separator finger and interlocking complementary structure formed from plastic for moving along the fastener, the complementary structure comprising a transverse support member having said separator finger depending therefrom, a pair of legs depending from said support member on opposite sides of said support member and on opposite sides of said finger, a pair of side walls hinged to the opposite sides of said support member at the top thereof and on opposite sides of the respective legs, said side walls being foldable relative to said separator finger and having openings therein for receiving said depending legs, and means for interlocking said side walls to said depending legs comprising shoulder structure extending along the an edge of each of said depending legs and flexible tongue structure extending along a corresponding edge in each of said side walls, said flexible tongue structure being depressible by the edge of said depending legs and adapted to snap into engagement with the respective shoulders on said legs to provide a compression-type latch for locking said side walls in their folded position, said side walls extending from an opening end of the slider to the closing end, the side walls being spaced wider apart at the opening end to permit separation of the rib and groove elements by the separator finger extending between the side walls at the opening end, the side walls being spaced sufficiently close together at the closing end to press the rib and groove elements into interlocking relationship as the slider is moved in a fastener closing direction, at least one of said side walls having shoulder structure on the bottom thereof for cooperating with the bottom of the fastener to prevent the slider from being lifted off the top edge of the fastener while the slider straddles the fastener.