Self-centering bottom block assembly

Claim 1

In a vertical D.C. casting apparatus for light metals comprising an open-ended D.C. mold and a bottom block assembly adapted to be inserted into said mold prior to casting the improvement comprising a. a bottom block adapted to be inserted into said mold and having sufficient dimensions to thereby seal the discharge end of said mold; b. a vertically movable member smaller than the bottom block upon which the bottom block is supported, the upper horizontal surfaces of said member adapted for slidable contact with said bottom block; c. retaining means to loosely lock said bottom block to said support member so as to allow horizontal movement of said bottom block; d. a plurality of vertically disposed guide surfaces below the bore of said mold and separate therefrom and in a fixed spacial relationship therewith, said guide surfaces being positioned no closer than the projected perimeter of the mold bore and thereby adapted to guide said bottom block into said mold bore; and e. a plurality of guide means associated with said bottom block which are adapted to ride on said guide surfaces as the bottom block is raised into position within the mole or withdrawn therefrom for aligning said bottom block with respect to said mold and preventing contact between said bottom block and said bore.