Apparatus for forming steps in manholes and the like

In a mold assembly, core members for use in said assembly to form cast bodies, said mold assembly having inner and outer mold members defining a hollow mold space therebetween, wherein one wall of one of said mold members is provided with rectangular shaped openings which define locations for anchoring rod-like members to said cast body, each core member comprising:

• a one-piece elongated hollow molded plastic body of rectangular cross-section having a first open end and a second sealed end, the length of said body being much greater than either width;
• first and second pairs of resilient flanges integrally joined to said body adjacent said open end and extending in a direction perpendicular to the longitudinal axis of said body;
• said first pair of flanges being substantially coplanar, said second pair of flanges being substantially coplanar and being spaced a predetermined distance inward from said first pair of flanges, said first and second pairs of flanges cooperating to embracing opposite surfaces of the marginal portion of said one mold member and surrounding said opening to maintaining the core member in proper alignment;
• at least one of said pair of flanges being resilient along their lengths in said transverse direction to facilitate continuous bending thereof;
• said core members each being inserted into each of said openings from a first side of said wall, whereby, upon insertion, said flexible flanges are adapted to flex to clear the opening and after insertion, snap-free of the associated opening to position said first and second pairs of flanges along opposite surfaces of the opening in the mold wall to retain the core member in position prior to insertion of the casting material and, upon withdrawal of the cast body from the mold, to enable one of the pairs of flanges to snap-free of the wall opening and return to the unflexed position while said core member is retained in the hardened casting material being removed from the mold.