US3750998A

US3750998A - Composite form with liner plates

Info

Publication number: US3750998A
Application number: US00207189A
Authority: US
Inventors: T Shoe; R Smith
Original assignee: FLEXICORE CO
Current assignee: FLEXICORE CO; FLEXICORE CO INC US
Priority date: 1971-12-13
Filing date: 1971-12-13
Publication date: 1973-08-07
Anticipated expiration: 1990-08-07
Also published as: CA979624A

Abstract

A composite slab casting form particularly adapted to resist the transverse deflection forces generated by the weight of concrete in the form. The base or pan of the form is constructed from a relatively thick, flat, plate member having a pair of longitudinally extending notches machined in its upper surface. A pair of relatively thin liner plates are bent about longitudinally extending axes to form base leg portions and side leg portions joined by a smoothly curved connecting section. The liner plates are mounted on the pan with the base leg portions thereof received in the notches. Longitudinally extending voids are defined by the inner ends of the base leg portions and opposing portions of the notches in the pan and these voids are filled with a welding material, which is thereafter ground to provide a smooth flat surface coplanar with the upper surface of the pan and the adjoining surface of the liner plate. In bending the liner plates to provide the base and side leg portions the base leg portions are formed long enough to space the above mentioned welding material far enough away from the connecting section that the welding material can be readily ground with conventional tools without gouging, undercutting or otherwise blemishing the surfaces of the form.

Description

United States Patent Shoe et al. Aug. 7, 1973 COMPOSITE FORM WITH LINER PLATES [57] ABSTRACT (75] ln en o Theodore Shoe, Fletcher; Robert A composite slab casting form particularly adapted to E. Smith, Kettering, both of Ohio resist the transverse deflection forces generated by the wei ht of concrete in the form. The base or an of the [73] Asslgnee' Flexlcore Dayton forri i is constructed from a relatively thickfilat, plate member having a pair of longltudinally extendmg [22] Filed: Dec. 13, 1971 notches machined in its upper surface. A pair of rela- [21 1 pp No 207 189 tively thin liner plates are bent about longitudinally extending axes to form base leg portions and side leg portions joined by a smoothly curved connecting section.

[52] US. Cl. 249/50 The liner plates are mounted on the pan with the base 1328b 1323b leg portions thereof received in the notches. Longitudi- [58] Field of Search 249/50; 164/157, nally extending voids are defined by the inner ends of 16 /3 237/2092 8 B the base leg portions and opposing portions of the notches in the pan and these voids are filled with a [56] References Cited welding material, which is thereafter ground toprovide UNITED STATES ENTS a smooth flat surface coplanar with the upper surface 3 618,888 11 1971 Wise 249 50 of the and the adjoining surface of the liner a 3:023,477 3/1962 Smith et al... 4. 249 50 hl bending the liner Plates to Provide the base and slde 687,740 12 1901 French 287/2092 D g Portions the base leg portions are formed long 2,163,209 6/1939 Pungel ZEN/189.36 B enough to space the above mentioned welding material 2,376,574 5/1945 Collins 287/189.36 B X far enough away from the connecting section that the Primary Examiner-J. Spencer Overholser Assistant ExaminerBen D. Tobor AttorneyMarechal, Biebel, French & Bugg welding material can be readily ground with conventional tools without gouging, undercutting or otherwise blemishing the surfaces of the form.

4 Claims, 2 Drawing Figures COMPOSITE FORM WITH LINER PLATES BACKGROUND OF THE INVENTION A form is disclosed in U. S. Pat. No. 3,023,477 for casting prestressed concrete slabs of some 60 feet or more in length and approximately 2 feet in width. This form is constructed, basically, from a sheet of high tensile strength steel to permit it to be flexed in a stripping fixture so that the cured slabs can be removed therefrom. In casting wider slabs, however, difficulties are encountered due to the increased transverse deflection forces generated by these wider slabs. Since the lower surfaces of the slabs serve as finished ceiling surfaces they must be relatively flat.

The invention disclosed in the above noted, related application overcomes these difficulties by forming the pan of the casting form as a plate of thick steel having a pair of notches machined in its upper surface. A pair of relatively thick side plates are provided which are machined to provide each of them with an upstanding side leg portion joined by a radius to an inwardly projecting base leg and an inwardly projecting grout key cavity forming protrusion projecting inwardly from the side leg. The side plates are mounted in the notches with the bottom edges of the side plates engaging the bottom wall of each of the notches. The cavities formed by the inner ends of the base legs and opposing walls of the notches are filled with welding material which is then ground to provide a smooth flat surface.

The form thus constructed provides a solution to the problem of increased transverse deflection forces encountered in casting relatively wide concrete slabs and by machining the side plates so that the base legs extend inwardly from the curved connecting portions a sufficient distance, the welding deposited in the cavities described above may be ground without damaging adjacent surfaces of the form. This is important of course, since, as noted above, the lower surfaces of the slabs serve as finished ceiling surfaces. Additionally, undercutting in the vertical walls of the form may lead to difficulties in form stripping and chipping. It will be apparent, however, that the construction of a form as described above will involve expenses of machining the side plates to provide the desired configuration and that it would be desirable to avoid this expense while still retaining the advantages of the invention.

SUMMARY OF THE INVENTION A composite slab casting form in accordance with the present invention includes a relatively thick, flat, base plate or pan adapted to resist the transverse deflection forces encountered when the form is filled with concrete. Additionally, the pan is provided with a pair of longitudinally extending recesses adapted to receive portions of the side wall members and the inner ends of these members are spaced inwardly of the form so that there is little danger of marring the surface of the form during grinding operations.

However, rather than forming the side walls of the form from relatively thick side plates machined to the desired contour, a pair of relatively thin side plates are utilized, bent about longitudinally extending axes to provide side leg portions and base leg portions interconnected by a smoothly curved section. As in the above noted related application, the inner ends of the base leg portions extend far enough into the form away from the intersection of the base and side legs such that BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view showing a form in accordance with the present invention; and

FIG. 2 is a cross-sectional view through the form of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT As seen in FIGS. 1 and 2 of the drawings, a form 10 in accordance with the present invention includes a relatively thick base plate 12 somewhat wider than the desired width of the slab to be cast therein. For example, the base plate 12 might be approximately 55 inches wide if slabs of approximately 4 feet in width are to be produced. Spaced inwardly of its longitudinally extending side edges 14 the base plate 12 is provided with longitudinally extending notches 16.

A pair of reenforcing plates 18, which may also be of substantial thickness, have their. lower edges 20 received in the notches 16 with a lower portion of their outer faces 22 abutting an outer wall 24 of the notch 16 and their lower surface 20 engaging the opposed surface of the notch 16. The reenforcing plates 18 are then secured to the base plate 12 by means of welding, as indicated at 26 and 28.

Positioned within the form 10 are opposed pairs of upper and lower

side plate sections

28 and 30, respectively. Each upper side plate section 28 includes an upper portion 34, which extends substantially perpendicularly with respect to an upper surface 36 of the base member 12, and a lower portion 38 which slants inwardly away from the base of the form and from which protrusions 39 are stamped or otherwise formed. Protrusions 39 in a finished slab will form a series of interrupted cavities to permit adjacent slabs to be keyed to each other with grout. The proper spacing of the upper portion 34 of the side plate 28 is maintained by means of spacer plates 40 positioned between the upper sections 34 and the reenforcing plates 18 and secured thereto by welding.

The lower sections 30 each include a side leg 42 overlying a bottom portion of the reenforcing plate 18 and a base leg 44 connected thereto by means of a smoothly curved section 46. The space between the lower edge of each of the upper side plate sections 28 and the upper edge of the lower side plate sections 30 is filled by means of welding, as indicated at 48 and this weld is ground or finished to provide a smooth surface. Additionally, it will be noted from FIG. 1 that the ends of the form will be sealed, as at 50 and 51, to prevent the penetration of foreign material between the various elements of the form.

The voids defined by the inner ends 52 of the base legs 44 and the adjacent walls of the notches 16 are filled by means of a weld material 53, wich is thereafter ground to provide a smooth continuous transition between the upper surfaces of the base legs and the base plate. A cap member 54 is secured to the upper edge of the upper side plate section 28 and the upper edge of the reenforcing plate 18 by means of welds or the like, and projects outwardly over the longitudinally extending edges 14 of the base plate 12.

Because the base legs 44 extend inwardly of the form and thereby position the welds 53 a distance inwardly of the curved sections 46, the welds 53 may be ground by means of conventional tools without danger of gouging adjacent portions of the form, as would be the case if the liner plates terminated at or near the curved portions 46 thereof. As a result, gouging of the form surfaces, which would retract from the usefulness of the slabs in providing finished ceilings, and the formation of undercut areas in the vertical walls of the form, which would hinder the removal of the slabs from the forms, is obviated.

Additionally, because the side plates are of relatively light gauge material, as compared to the thickness of the base plate 12 for example, they may be shaped by stamping to provide a shape difficult to produce by machining, such as the smoothly curved sections 46 and the protrusions 32. Also as a result of the use of thin side plates, the depth of the notch 16 in the base plate may be maintained at a minimum. Since, as noted above, the base plate will be flexed by a stripping fixture to remove the cured slab therefrom, it is desirable, from a standpoint of structural integrity of the base plate, to remove as little material as possible in forming the notch 16.

While the side plates are described as formed in separate upper and lower sections, it will be apparent that the upper and lower sections may be combined and each side plate formed from a continuous sheet of metal. Additionally, although the upper sections of the side plates are fomed with a series of protrusions to provide interrupted grout keying cavities in the finished slab, it will be apparent that a continuous, inwardly projecting rib could also be used to provide longitudinally extending grout keying cavities on each side of the finished slab. However, where keying against horizontal as well as vertical inter slab movement is desired, the construction described above will be preferred.

The thickness of the pan should be between approximately three-eighths inch and three-fourths inch with the optimum thickness being approximately fiveeighths inch. Thus, the pan must be thick enough to resist deflection, since the finished slab must be relatively flat for purposes of appearance as well as for structural reasons, and the maximum thickness of the pan is controlled by a consideration of the tensile strength of the steel of the pan and the depth and design details of the keyway forming protrusion since this affects the amount the pan must be flexed during the stripping operation.

in a typical construction-the base plate 12 may be approximately fiveeighths inch in thickness, the notch 16 formed therein of approximately three-sixteenths inch in depth and the side plates approximately the same thickness as the depth of the notches 16 and having a radius of bend of from five-eighths inch to one-fourth inch, with three-eighths inch an optimum. The face 24 of the notch 16 may be spaced inwardly from the edge 14 of the base plate a distance approximately 2 inches and the reenforcing plate 18 have been formed approximately 19% inch in thickness.

The cap member 54 may be one inch in thickness and approximately 4% inches in width and overhang longitudinally extending edges 14 of the base plate about an inch, while the spacer plate 40 may be approximately 1% inch in height and five thirty-seconds inch in thickness. Conveniently, the interior width of the form may be approximately four feet or more, although it may of course be narrower for filler or other narrow slabs, and the overall height and length of the form of convenient dimensions for commercial operation. For example, the internal depth of the form may range from 6 inches to 16 inches while the length of the form may be approximately feet.

While the form of apparatus herein described consti' tutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

l. A composite form comprising:

a. a relatively thick, flat base pan,

b. means defining a pair of longitudinally extending notches in an upper surface of said pan,

c. a pair of relatively thin liner plates having inner and outer faces and top and bottom edges and a thickness no greater than the depth of said notches,

d. said liner plates being bent along axes extending substantially longitudinally thereof and providing base leg portions and side leg portions joined by radius sections coincident with said bending axes,

e. said liner plates being received in said notches with said inner surfaces thereof at said base leg portion substantially coplanar with said upper surface of said pan and said bottom edges of said liner plates spacedfrom opposing portions of said notches and defining therewith a pair of longitudinally extending voids,

f. hardenable material filing said voids and having an upper surface substantially coplanar with said pan upper surface and said inner surfaces of said liner plates at said base leg portions, and

g. means for reenforcing said liner plates.

2. The composite form of claim 1 wherein said reenforcing means comprises:

a. a pair of upstanding reenforcing plates,

b. said reenforcing plates being mounted on said pan in underlying relationship to said liner plates at said side leg portions thereof.

3. The composite form of claim 1 wherein:

a. the thickness of said liner plates is substantially equal to the depth of said notches.

4. A composite form comprising:

a. an elongated, substantially planar base pan,

b. means defining longitudinally extending notches in an upper surface of said base pan adjacent to and spaced inwardly of said edges of said pan,

c. a pair of elongated reenforcing plates,

(1. means attaching said reenforcing plates to said pan with lower edges of said reenforcing plates received in said notches,

e. spaced pairs of upper and lower side plate sections,

f. said side plate lower sections being of substantially the same thickness as the depth of said notch and bent about longitudinally extending axes providing: i. a base leg portion,

ii. a side leg portion, and iii. a smoothly curved section joining said base and side leg portions,

received in said notches and extending inwardly away from said curved sections and defining with adjacent opposed walls of said notches longitudinally extending voids, and

weld means filling said voids and providing a smooth, continuous transition surface from said upper surface of said pan to said side plates.

Claims

1. A composite form comprising: a. a relatively thick, flat base pan, b. means defining a pair of longitudinally extending notches in an upper surface of said pan, c. a pair of relatively thin liner plates having inner and outer faces and top and bottom edges and a thickness no greater than the depth of said notches, d. said liner plates being bent along axes extending substantially longitudinally thereof and providing base leg portions and side leg portions joined by radius sections coincident with said bending axes, e. said liner plates being received in said notches with said inner surfaces thereof at said base leg portion substantially coplanar with said upper surface of said pan and said bottom edges of said liner plates spaced from opposing portions of said notches and defining therewith a pair of longitudinally extending voids, f. hardenable material filing said voids and having an upper surface substantially coplanar with said pan upper surface and said inner surfaces of said liner plates at said base leg portions, and g. means for reenforcing said liner plates.

2. The composite form of claim 1 wherein said reenforcing means comprises: a. a pair of upstanding reenforcing plates, b. said reenforcing plates being mounted on said pan in underlying relationship to said liner plates at said side leg portions thereof.

3. The composite form of claim 1 wherein: a. the thickness of said liner plates is substantially equal to the depth of said notches.

4. A composite form comprising: a. an elongated, substantially planar base pan, b. means defining longitudinally extending notches in an upper surface of said base pan adjacent to and spaced inwardly of said edges of said pan, c. a pair of elongated reenforcing plates, d. means attaching said reenforcing plates to said pan with lower edges of said reenforcing plates received in said notches, e. spaced pairs of upper and lower side plate sections, f. said side plate lower sections being of substantially the same thickness as the depth of said notch and bent about longitudinally extending axes providing: i. a base leg portion, ii. a side leg portion, and iii. a smoothly curved section joining said base and side leg portions, g. said side plate upper sections each including a series of grout key forming protrusions adapted to project inwardly of said form, h. means attaching said side plates to said reenforcing plates with said upper sections and said side leg portions of said lower sections overlying opposing faces of said reenforcing plates, i. said base leg portions of said lower sections being received in said notches and extending inwardly away from said curved sections and defining with adjacent opposed walls of said notches longitudinally extending voids, and j. weld means filling said voids and providing a smooth, continuous transition surface from said upper surface of said pan to said side plaTes.