Snap fastener for belt driven cartridge

Claim 1

A belt driven magnetic tape cartridge housing, comprising: a rigid, one-piece, flat base including two opposed major surfaces and a plurality of walls extending from one major surface to the other to define circular holes having a reduced diameter adjacent said one major surface; a resilient cover including a flat top wall having an inner surface spaced from and facing said one major surface of said flat base, two opposed side walls depending from said top wall to contact said one major surface of said base, opposed front and back walls depending from said top wall to contact said one major surface of said base, and a plurality of snap fasteners equal in number to said circular holes and extending from said cover inner surface and adapted to engage said walls defining said circular holes and releasably secure said cover to said base, each of said snap fasteners including: a solid body portion attached to said top wall inner surface; a bifurcation defined by slot; two spring arms extending from said bifurcation toward said one major surface of said base and one of said holes, said spring arms being capable of resilient deflection toward each other within said slot and being substantially perpendicular to said top wall inner surface and said one major surface of said base when undeflected; said arms terminating in enlarged heads for insertion through said hole, which heads have a dimension parallel to said slot which is equal to or less than said hole, a combined dimension transverse to said slot when said arms are undeflected which is greater than that of said hole, and a combined dimension transverse to said slot when said arms are deflected toward each other which is less than that of said hole; and reduced neck portions on each arm adjacent said heads which have a dimension parallel to said slot which is less than or equal to that of said hole to allow insertion of said neck portions into said hole, and a combined dimension transverse to said slot which is substantially equal to that of said hole when said spring arms are undeflected; said spring arms further include shoulders which have a dimension parallel to said slot or a combined dimension transverse to said slot when said spring arms are deflected which is greater than that of said wall defining said hole to limit insertion of said spring arms into said hole; wherein contact between said enlarged heads and said hole causes deflection of said spring arms toward each other which allows passage of said heads through said hole and wherein passage of said heads through said hole permits the resilient return of said spring arms to said undeflected position and contact between said neck portions and said hole whereby said snap fastener is retained in said hole by expansion of said enlarged heads to a dimension greater than said hole; and wherein the length of said spring arms is sufficient to provide lateral resiliency capable of accommodating differential expansion of said cover relative to said base so that said cover may expand in the plane of said top wall to an unequal extent as compared to expansion of said base in the plane of said base without causing deflection of said cover or said base from their flat configuration.