Method of stripping slab casting forms

Claim 1

In a method of stripping from a cured structural slab a metal slab casting form having a bottom pan, opposed upstanding side walls affixed permanently to said bottom pan extending longitudinally of said form, portions extending outwardly of said longitudinally extending side walls and grout keyway forming protrusions projecting from said side walls inwardly of said form, the steps comprising: a. engaging said outwardly extending portions of said form with first form engaging means, b. engaging said form with second form engaging means longitudinally thereof at locations thereon spaced transversely outwardly a substantial distance from the center of said form, adjacent said opposite longitudinally extending side edges and inwardly from said first form engaging means, and c. applying opposing forces through said first and second form engaging means to said form in sufficient magnitude to cause said bottom pan to flex inwardly of said form to a curved configuration without overstressing said bottom pan to cause said side walls to move outwardly with respect to said form a distance sufficient to clear said protrusions from grout keyways formed thereby in a cured slab cast in said form.

Claim 8

A method of stripping from a cured slab having grout keying cavities in opposite side edges thereof a slab casting form having a bottom pan, side walls projecting upwardly from longitudinally extending side edges of said bottom pan, protrusions for forming said grout keying cavities in said slab projecting from said side walls inwardly of said form, each of said protrusions having a sloped lower surface sloping outwardly of said form toward said bottom pan and having a slope no greater than the slope of an arc swung through the inner most point with respect to said form on said protrusions from a center located on said pan a distance spaced inwardly from said longitudinally extending side edges thereof a distance equal to U/4 + 2Z/3 where said pan has a total width of U + 2Z and U is substantially greater than 2Z, comprising: a. applying a restraining force to said form at said outwardly projecting flange members, b. applying a flexing force against said bottom pan in opposition to said restraining force at points spaced inwardly of said longitudinally extending side edges of said pan a distance equal to Z and spaced from each other a distance equal to u by means of a pair of longitudinally extending bars having upper surfaces sloped outwardly and away from said bottom pan, c. flexing said pan without overstressing thereof by said opposing forces to an arched configuration such that said sloped upper surfaces of said bar members are substantially tangent to the curve of said arched configuration and said inner most point on each of said protrusions is clear of its associated grout keying cavities on said slab, and d. removing said slab form from said form while said pan is in said arched configuration.

Claim 9

A method of stripping from a cured slab having grout keying cavities in opposite side edges thereof a slab casting form having a bottom pan, side walls projecting upwardly from longitudinally extending side edges of said bottom pan, protrusions for forming said grout keying cavities in said slab projecting from said side walls inwardly of said form, each of said protrusions having a sloped lower surface sloping outwardly of said form toward said bottom pan and having a slope no greater than the slope of an arc swung through the inner most point with respect to said form on said protrusions from a center located on said pan a distance spaced inwardly from said longitudinally extending side edges thereof a distance equal to U/4 + 2Z/3 where said pan has a total width of U + 2Z and U is substantially greater than 2Z, comprising: a. applying a restraining force to said form at said outwardly projecting flange members, b. applying a flexing force against said bottom pan in opposition to said restraining force at points spaced inwardly of said longitudinally extending side edges of said pan a distance equal to Z and spaced from each other a distance equal to u by means of a pair of longitudinally extending bars having upper surfaces sloped outwardly and away from said bottom pan, c. flexing said pan without overstressing thereof by said opposing forces to an arched configuration such that said sloped upper surfaces of said bar members are substantially tangent to the curve of said arched configuration and said inner most point on each of said protrusions is clear of its associated grout keying cavities on said slab, and d. removing said slab form from said form while said pan is in said arched configuration.