Apparatus for stripping slab casting forms

Claim 2

Apparatus for stripping from a cured slab a casting form having a bottom pan, upstanding side walls and grout keying protrusions projecting inwardly of said form from each of said side walls comprising: a. first means for engaging said form outwardly of longitudinal side edges of said bottom pan, b. second means for engaging said form at spaced locations extending longitudinally thereof inwardly of and in opposition to said first means and outwardly of the center of said pan, and c. means for moving said first and second form engaging means relative to each other in opposing directions with said form engaged therebetween a distance sufficient to cause said side walls to move outwardly of said form, said bottom pan to flex upwardly in a curve and said grout keying protrusions to clear cavities formed thereby in a slab cast in said form.

Claim 3

The apparatus of claim 1 wherein: a. said second form engaging means include longitudinally extending bars.

Claim 4

The apparatus of claim 2 wherein: a. each of said bars has a sloped upper surface extending downwardly and outwardly of said apparatus, and b. said sloped upper surfaces of said bars are substantially tangent to the curve formed by said pan.

Claim 5

The apparatus of claim 1 wherein: a. said second form engaging means are spaced inwardly of said first form engaging means in a position for engaging said bottom pan inwardly of longitudinally extending side edges thereof.

Claim 6

The apparatus of claim 1 wherein: a. said second form engaging means are spaced inwardly from opposite longitudinally extending side edges of said pan a distance equal to Z, b. said second form engaging means are spaced from each other a distance equal to U, and c. U is substantially greater than 2Z.

Claim 7

Apparatus for stripping from a cured slab a casting form having a bottom pan, upstanding side walls and grout keying protrusions projecting inwardly of said form from each of said side walls comprising: a. first means for engaging said form outwardly of longitudinal side edges of said bottom pan, b. second means for engaging said form at locations extending longitudinally thereof outwardly of the center of said pan, inwardly of said side edges a distance equal to Z, spaced from each other a distance equal to U, and in opposition to said first form engaging means, c. means for moving said first and second form engaging means relative to each other in opposing directions with said form engaged therebetween a distance sufficient to cause said side walls to move outwardly of said form, said bottom pan to flex upwardly in a curve and said grout keying protrusions to clear cavities formed thereby in a slab cast in said form, and d. said first and second form engaging means being positioned relative to each other and to said form such that centroids of the bending moments applied to each side of said pan during flexing thereof are located inwardly of the longitudinal edge of that side of said pan a distance equal to approximately U/4 + 2Z/3.

Claim 8

Apparatus for stripping from a cured slab a casting form having a bottom pan, upstanding side walls and grout keying protrusions projecting inwardly of said form from each of said side walls comprising: a. first means for engaging said form outwardly of longitudinal side edges of said bottom pan, b. second means for engaging said form at locations extending longitudinally thereof outwardly of the center of said pan, inwardly of said side edges a distance equal to Z, spaced from each other a distance equal to U, and in opposition to said first form engaging means, c. means for moving said first and second form engaging means relative to each other in opposing directions with said form engaged therebetween a distance sufficient to cause said side walls to move outwardly of said form, said bottom pan to flex upwardly in a curve and said grout keying protrusions to clear cavities formed thereby in a slab cast in said form, and d. said first and second form engaging means being positioned relative to each other and to said form such that centroids of the bending moments applied to each side of said pan during flexing thereof are located inwardly of the longitudinal edge of that side of said pan a distance equal to approximately U/4 + 2Z/3.

Claim 9

Apparatus for stripping from a cured slab a casting form which includes an elongated bottom pan having a width equal to U + 2Z, upstanding side walls, flanges projecting outwardly from said form and grout keying protrusions projecting inwardly of said form from each of said side walls comprising: a. hold down means for engaging said outwardly projecting flanges, b. a pair of longitudinally extending bars adapted to engage the bottom pan of said form at points spaced inwardly of longitudinally extending side edges of said form a distance equal to Z and a transverse distance from each other equal to U, c. each of said bars having a substantially flat upper surface and a sloped upper surface sloping downwardly and outwardly from said flat upper surface, d. the angularity of said sloping surface being such that said sloping surfaces are substantially tangent to the curved pan of said form when flexed an amount sufficient to move said side walls outwardly to a point where said protrusions thereon will clear grout cavities defined in a slab cast by said form, and e. means for moving said bars in opposition to said hold down means a distance sufficient to flex said bottom pan to a curved configuration curved to the extent that said sloping surfaces are tangent thereto.

Claim 10

Apparatus for stripping from a cured slab a casting form which includes an elongated bottom pan having a width equal to U + 2Z, upstanding side walls, flanges projecting outwardly from said form and grout keying protrusions projecting inwardly of said form from each of said side walls comprising: a. hold down means for engaging said outwardly projecting flanges, b. a pair of longitudinally extending bars adapted to engage the bottom pan of said form at points spaced inwardly of longitudinally extending side edges of said form a distance equal to Z and a transverse distance from each other equal to U, c. each of said bars having a substantially flat upper surface and a sloped upper surface sloping downwardly and outwardly from said flat upper surface, d. the angularity of said sloping surface being such that said sloping surfaces are substantially tangent to the curved pan of said form when flexed an amount sufficient to move said side walls outwardly to a point where said protrusions thereon will clear grout cavities defined in a slab cast by said form, and e. means for moving said bars in opposition to said hold down means a distance sufficient to flex said bottom pan to a curved configuration curved to the extent that said sloping surfaces are tangent thereto.