Abstract: The grip of the collar element of an existing circular manhole cover-supporting structure, such as a circular manhole frame, on a split-ring style expansion-joint-fitted manhole cover support inserted into, surrounded by, and forced by expansion against said collar element is improved by having selective stiffener means disposed in a sector of the cover support that is generally opposite to the expansion joint thereof, the stiffener means suppressing the tendency of the corresponding sector of the base ring to pull away from the collar element.

Abstract: An improvement for increasing the resistance of manhole cover supports to deformation is provided which comprises equipping the upper edge or flange thereof with a succession of pressed-in gussets, the troughs of which slope with respect to the keeper of said cover support or equipping a keeper wall thereof with a succession of pressed-out gussets.

Abstract: An ingot mold provided with means affording stress relief thereto for the ingot pouring operation, while maintaining the mold in condition to aid in preventing metal leakage therefrom during the ingot pouring operation and subsequent cooling of the ingot, and providing mold wall support for the ingot until its skin has sufficient structural integrity to support the molten interior of the ingot, and a mold which can be recycled for use in a faster manner as compared to heretofore utilized solid or one-piece type ingot molds. In certain embodiments, the mold is formed of a plurality of completely separate and individual side wall sections defining at least the side periphery of a mold cavity, together with coupling means connecting the wall sections together. The coupling means provide for expansion and contraction of the mold sections relative to one another during the pouring of molten metal into the mold, and the resultant heating and subsequent cooling thereof.