Monolithic precast invert system
AssigneeA-Lok Products, Inc.
InventorJack Ditcher
Life of this patent
Estimating the term…
Abstract
Concentric inner and outer molds define the walls of the manhole base to be cast. The top of the inner mold is provided with a stationary invert forming section and at least one swingable invert forming section swingably mounted upon a centrally located pivot pin. The invert forming mold member is provided with locating openings adapted to receive the pin within the swingable invert forming section to positively and accurately locate the swingable invert forming section. The open region between the fixed and movable sections is filled with a "knee" member in the form of a hollow curved shell which defines the central portion of the invert. The top of the inner mold may alternatively be provided with two or more swingably mounted invert forming sections.
Claims11
Apparatus for forming a manhole base comprising:
- inner and outer mold members defining an interior volume having a cylindrical shape;
- gasket retaining assemblies arranged between said mold members for retaining a gasket to be molded into the manhole base and for forming openings in said manhole base member;
- an invert-forming member supported on said inner mold member and having an invert-forming surface;
- said invert-forming member having a first elongated invert-forming section arranged on said invert-forming surface;
- a second swingable elongated invert-forming section swingably mounted at a central point upon the invert-forming surface of said invert-forming member and having an inner end arranged a spaced distance from the adjacent end of said first invert-forming section;
- hollow shell means having a substantially U-shaped cross-section and a shape conforming to the angle formed by the longitudinal axes of said first and second invert-forming sections and having an open bottom end removably positioned upon said invert-forming surface and within the gap region between the adjacent ends of said sections for filling said gap region to define a continuous invert of uniform cross-section along the length of said invert extending between the openings in said manhole base;
- and
- said invert-forming sections each having means for releasably mounting said gasket retainer assemblies thereto during the casting operation.
The apparatus of claim 2, wherein said swingable invert-forming section is comprised of a generally semi-cylindrical shaped invert-forming section and an elongated rod joined to the inner end of said invert forming section;
- a pin secured to said invert-forming member and extending through an opening at the free end of said rod for pivotally supporting said rod and enabling said invert-forming section to be swung about said pin.
Dependencies are inferred from the claim text.