Manufacturing process for a floor tile

1. A process for forming a floor tile for a raised floor system, comprising the steps of:

forming a box-shaped support pan having a shallow upwardly-opening compartment defined by a bottom wall of the pan and upright side walls which join to edges of the bottom wall and protrude upwardly and terminate at top edges;

forming a plurality of one-piece concrete sub-blocks having a thickness which equals or slightly exceeds the depth of the shallow compartment;

positioning a predetermined plurality of preformed concrete sub-blocks in horizontally adjacent side-by-side relationship so that the sub-blocks, when opposed edge faces of said sub-blocks are sidewardly engaged with one another, define a plan-view profile which substantially corresponds to the plan view profile of the compartment;

applying an adhesive to at least one edge face of each opposed pair of edge faces as defined on said sidewardly adjacent sub-blocks;

pressing said sub-blocks sidewardly together to effect fixed securement of said sub-blocks at said opposed contacting edge faces due to curing of said adhesive so as to define a preformed one-piece main concrete block having a plan-view profile which substantially corresponds to said compartment;

applying adhesive to one of (1) the bottom surface of said preformed main concrete block and (2) the inside surface of said pan bottom wall;

applying adhesive to one of (1) inside surfaces of the pan side walls and (2) the edge faces of said preformed main concrete block;

deflecting the side walls of the pan outwardly prior to positioning of the main concrete block into the compartment;

then positioning the preformed main concrete block into said compartment of said pan so that the bottom surface of said main block contacts the pan bottom wall;

deflecting the pan side walls inwardly into engagement with the edge faces of the main block after the main block has been positioned within the compartment of the pan; and

allowing the adhesive at contact areas between the pan and the main concrete block to cure to effect fixed securement of the block to and within the pan.

2. A process according to claim 1 , including the step of forming, in the corners of the pan where the side walls join, slits which open downwardly from the top edges of the side walls so that the side walls are cantilevered upwardly and are sidewardly deflectable relative to the bottom wall of the pan.

3. A process according to claim 1 , including the steps of providing the side walls of the pan with reversely bent outer edge flanges at the top edges thereof, gripping the edge flanges to deflect the side walls outwardly, and releasing the grip on the flanges so that the side walls resiliently deflect inwardly to engage edge faces of the main block.

4. A process according to claim 1 , including the steps of initially positioning both the pan and main block in vertically inverted positions with said pan being positioned in spaced relation above the main block, and then relatively moving the pan and block vertically together, with the side walls deflected outwardly, to effect seating of the block within the pan compartment.

5. A process for forming a floor tile for a raised floor system, comprising the steps of:

forming a box-shaped support pan having a shallow upwardly-opening compartment defined by a bottom wall of the pan and upright side walls which join to edges of the bottom wall and protrude upwardly and terminate at top edges;

forming a plurality of one-piece concrete sub-blocks having a thickness which equals or slightly exceeds the depth of the shallow compartment;

positioning a predetermined plurality of preformed concrete sub-blocks in horizontally adjacent side-by-side relationship so that the sub-blocks, when opposed edge faces of said sub-blocks are sidewardly engaged with one another, define a plan-view profile which substantially corresponds to the plan view profile of the compartment;

applying an adhesive to at least one edge face of each opposed pair of edge faces as defined on said sidewardly adjacent sub-blocks;

pressing said sub-blocks sidewardly together to effect fixed securement of said sub-blocks at said opposed contacting edge faces due to curing of said adhesive so as to define a preformed one-piece main concrete block having a plan-view profile which substantially corresponds to said compartment;

applying adhesive to one of (1) the bottom surface of said preformed main concrete block and (2) the inside surface of said pan bottom wall;

applying adhesive to the inside surfaces of the pan side walls;

deflecting the side walls outwardly away from the compartment;

then positioning the main block into the compartment so that the bottom surface of the block contacts the bottom wall of the pan;

deflecting the side walls inwardly so that the adhesive-coated inner surfaces of the side walls grip the respective opposed edge faces of the main block; and

permitting the adhesive to cure to fixedly secure said main block to the bottom wall and side walls of the pan.

6. A process according to claim 5 , wherein the sub-blocks of said predetermined plurality are identical and are rectangular in plan-view profile.

7. A process according to claim 6 , wherein the predetermined plurality of preformed sub-blocks includes only three identical preformed sub-blocks for defining the plan-view profile of the compartment.

8. A process according to claim 5 , including the step of finishing selected side edge faces of the sub-blocks before the sub-blocks are adhesively fixed together to define said main block.

9. A process for forming a floor tile for a raised floor system, comprising the steps of:

providing a box-shaped support pan having a shallow upwardly-opening compartment defined by a bottom wall of the pan and upright side walls which join to edges of the bottom wall and protrude upwardly and terminate at top edges;

molding a plurality of generally rectangular one-piece concrete sub-blocks having a thickness which equals or slightly exceeds the depth of the shallow compartment;

effecting surface finishing of edge faces of the molded sub-blocks to provide finished edge faces with improved uniformity and flatness;

positioning a predetermined plurality of said preformed concrete sub-blocks in horizontally adjacent side-by-side relationship so that the sub-blocks, when opposed finished edge faces of said sub-blocks are sidewardly engaged with one another, define a plan-view profile which substantially corresponds to the plan view profile of the compartment;

applying an adhesive to at least one finished edge face of each opposed pair of edge faces as defined on said sidewardly adjacent sub-blocks;

pressing said sub-blocks sidewardly together to effect fixed securement of said sub-blocks at said opposed contacting edge faces due to curing of said adhesive so as to define a preformed one-piece main concrete block having a plan-view profile which substantially corresponds to the plan-view profile of said compartment;

applying adhesive to one of (1) the bottom surface of said preformed main concrete block and (2) the inside surface of said pan bottom wall;

applying adhesive to one of (1) inside surfaces of said pan upright side walls and (2) exposed edge faces of said preformed main concrete block;

positioning the preformed main concrete block into said compartment of said pan so that the bottom surface of said main block contacts and presses against the pan bottom wall, and the edge faces of said main block contact and press against the inside surfaces of the pan side walls; and

allowing the adhesive at contact areas between the pan and the main concrete block to cure to effect fixed securement of the block to and within the pan.

10. A process according to claim 9 , including the step of the applying adhesive to the inside surfaces of the pan side walls and the bottom surface of said preformed main concrete block prior to positioning the main block into said compartment.

11. A process according to claim 10 , including the steps of initially positioning both the pan and main block in vertically inverted positions with said pan being positioned in spaced relation above the main block, and then relatively moving the pan and block vertically together to effect seating of the block within the pan compartment.

12. A process according to claim 9 , wherein the predetermined plurality of preformed sub-blocks includes only three identical preformed sub-blocks for defining the plan-view profile of the compartment.

13. A process according to claim 9 , comprising the additional steps of:

providing a mold for forming said concrete sub-blocks, said mold containing therein a large number of mold cavities for forming the sub-blocks, the mold cavities having an upright orientation for defining a sub-block having length and width dimensions which are several times greater than the thickness dimension of the sub-block, the sub-block when formed in the mold cavity being disposed with one of its width and length dimensions disposed in an upright orientation;

providing a dry concrete mix containing Portland cement and aggregate and a minimal quantity of water, the water quantity being no more than 10 percent by weight of the dry concrete mix weight;

filling the mold cavities with the dry concrete mix to create the sub-blocks therein;

removing the sub-blocks from the mold cavities and permitting additional drying thereof prior to effecting surface finishing of the edge faces thereof.

14. A process for forming a floor tile for a raised floor system, comprising the steps of:

providing a support pan having a shallow upwardly-opening compartment defined by a bottom wall of the pan and upright side walls which join to edges of the bottom wall and protrude upwardly therefrom;

providing a mold for forming concrete sub-blocks, said mold containing therein a large number of mold cavities for forming the sub-blocks, the mold cavities having an upright orientation for defining sub-blocks having length and width dimensions which are several times greater than the thickness dimension of the sub-block, the thickness dimension generally corresponding to the depth of the pan compartment, the sub-block when formed in the mold cavity being disposed with one of its width and length dimensions disposed in an upright orientation;

providing a dry concrete mix containing Portland cement, aggregate and water, the quantity of water being no more than 10 percent by weight of the dry concrete mix weight;

filling the mold cavities with the dry concrete mix to create the sub-blocks therein;

removing the sub-blocks from the mold cavities and permitting additional drying thereof;

grinding the edge faces of the molded sub-blocks to provide finished edge faces with improved uniformity and flatness;

positioning a predetermined plurality of said preformed concrete sub-blocks in horizontally adjacent side-by-side relationship so that the sub-blocks, when opposed finished edge faces of said sub-blocks are sidewardly engaged with one another, define a plan-view profile which substantially corresponds to the plan view profile of the compartment;

applying an adhesive to at least one finished edge face of each opposed pair of edge faces as defined on said sidewardly adjacent sub-blocks;

pressing said sub-blocks sidewardly together to effect fixed securement of said sub-blocks at said opposed contacting edge faces due to curing of said adhesive so as to define a preformed one-piece main concrete block having a plan-view profile which substantially corresponds to the plan-view profile of said compartment;

applying adhesive to one of (1) the bottom surface of said preformed main concrete block and (2) the inside surface of said pan bottom wall;

applying adhesive to one of (1) inside surfaces of said pan upright side walls and (2) exposed edge faces of said preformed main concrete block;

positioning the preformed main concrete block into said compartment of said pan so that the bottom surface of said main block contacts and presses against the pan bottom wall, and the inside surfaces of the pan side walls contact and press against the edge faces of said main block;

allowing the adhesive at contact areas between the pan and the main concrete block to cure to effect fixed securement of the block to and within the pan; and

effecting surface finishing of the exposed upper surface of the main concrete block.