Modular box spring mattress

A modular box spring mattress comprising two flexible plate units having a spring unit disposed between said plate units for biasing said plate units away from each other, said spring unit including a plurality of coiled compression springs and one of said flexible plate units comprising:

• a plurality of plate subunits joined together side by side defining at least one of the flexible plate units, each plate subunit having a substantially rectangular configuration and including a plurality of pins and a plurality of retaining holes formed along two adjacent sides thereof, a plurality of insertion members secured to the remaining adjacent sides thereof, said insertion members including a looped portion generally perpendicular to said subunits for insertion through said retaining holes in a side of an adjacent subunit so as to form a pin hole in an end portion of each of said looped portions, said pins being inserted through said pin holes so as to retain said subunits together;
• a plurality of annular flanges extending from each plate unit towards each other, said annular flanges of one of said plate units opposing said annular flanges of the other plate unit so that end turns of said compression springs are receivable within said annular flanges;
• a plurality of flexible retaining arms extending obliquely and inwardly from each of said annular flanges in a plane generally parallel to said plate subunits, the angle formed at the tangent of each flexible retaining arm and its respective annular flange being approximately 45.degree., said flexible retaining arms including end portions spaced apart from its corresponding plate subunits so that said end turns of said compression springs can be respectively retained between said flexible retaining arms and said plate subunits.