Separable plastic fastener and method and apparatus for manufacturing thereof

A separable plastic fastener which comprises:

• a pair of fastener pieces each including a flat base and a plurality of engagement projections provided on and integral with said base and arranged in a plurality of lateral and longitudinal rows, said engagement projections having heads of a uniform shape and a uniform size, each of said heads being supported on said base via a pair of opposed leg pieces united at the upper end thereof to opposed bottom surface edge portions of said head and wherein said base has small projections each projecting from a position corresponding to the center of four adjacent engagement projections in two adjacent lateral rows and two adjacent longitudinal rows, each of said small projections having a height corresponding to the difference between a height from the top of said base to the bottom of said head and a height from the bottom to the top of said head.

A separable plastic fastener comprising a pair of fastener pieces each including a flat base, a plurality of elastic engagement projections provided in a plurality of lateral and longitudinal rows on said base and each including a leg projecting from said base and a head supported by the distal end of said leg, and small projections each projecting from said base at a position corresponding to the center of four adjacent engagement projections in two adjacent lateral rows and two adjacent longitudinal rows, each of said small projections having a height corresponding to the difference between a height from the bottom of said head of each of said engagement projections to the top of said base and a height from the top of said head to the bottom thereof.