US3853976A - Method for casting slabfaced panels - Google Patents

Abstract

A process for joining preforms such as bricks is disclosed. A horizontal casting box having a floor provided within covering of resilient gasketing material is utilized. A gridwork is inserted into the casting box and shimmed to preclude lateral movement thereof, preforms are mechanically seated against the resilient gasketing material and into the grid by mechanical pressure, and a vacuum is drawn through openings in the resilient gasketing material opposite the preforms to hold the preforms in place. The mechanical pressure is terminated, the gridwork removed and a hardenable composition cast against the preforms to unite them into a unitary article.

Description

' United States Patent Kelsey Dec. 10, 1974 [54] METHOD FOR CASTING SLAB-FACED Primary Examiner-Robert F. White PANELS Assistant ExaminerThomas P. Pavelko Attorney, Agent, or Firm-Cushman, Darby and [75] Inventor. Paul S. Kelsey, Delray Beach, Fla. Cushman [73] Assignee: K. F. Brick Company, Inc., East [57] ABSTRACT A process for joining preforms such as bricks is disclosed. A horizontal casting box having a floor provided within covering of resilient gasketing material is 52 U.S. c1. 264/90, 264/261 utilized A gridwork is inserted into the Casting box 51 Int. Cl B32b 31/06 and Shimmed Pmlude lateral movement thereof, 58 Field of Search 264/261 90 Prefmms are mechanically Seated against the resilient gasketing material and into the grid by mechanical [56] References Cited pressure, and a vacuum is drawn through openings in the resilient gasketing material opposite the preforms UNITED STATES PATENTS to hold the preforms in place. The mechanical pres- 2,s25,221 3/1958 Brook 1. 264/261 sure is terminated, the gridwork removed and a ham g t g l enable composition cast against the preforms to unite y 35 en em 3,192,567 7/1965 Abernathy et a1... 264/261 them a mtary amcle' 3,242,549 Boeglen 3 C 9 a ing gures 000/ ,s aoz F20 5704/ Eve/p65 c/mw: 0/2 Mfl/Vflt/V/L your W Z4 /4 /6 B 2a ZZWZ Z2 38 a 4 40 42%;,

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INVENTOR B404 flszszy ATTORNEYS METHOD FOR CASTING SLAB-FACED PANELS BACKGROUND OF THE INVENTION The background of the slab-faced panel art is discussed extensively in my copending application Ser. No. 18,173, filed Mar. 10, 1970, entitled IMPROVED METHOD FOR CONSTRUCTION OF SLAB-FACED PANELS abandoned in favor or Ser. No. 25 l ,885 filed May 10, 1972, now U.S. Pat. No. 3,773,880, issued Nov. 20, 1973.

The U.S. Patent of Kastenbein, 2,855,653 shows a system for casting tile-faced panels which includes sucking the individual tiles against a resilient mat to produce simulated concave joints between adjacent tiles. The casting box described in Kastenbein is custom built for this particular purpose and, in order to allow use of high vacuum, isquite massiveand expensivein construction.

Experimentation has demonstrated that his impossible to vacuum seat evenasmall array of face-down brick, brick slabs, slate, glazed'tile or glazed brick that are just resting on even the softest of a sponge rubber surfaced vacuum pad. One cannot get satisfactory uniform vacuum sealing of commercially obtainable brick faces or brickslab faces without a-relatively heavyfpressure being exerted on the backsof such individual facings, up to 2 pounds persquare'inch. When one realizes that full solid brick ('3 )4 inches) only weigh about 0.28

pound per square inch and% inch thick brick slabs only weigh 0.067 poundper square inch, the inadequacy of each brick'or slabs ownweight is readily apparent. A 32 squarefoot .panel would have about 210 normal (2 $4 inches X 8 inches)-brick slabs, anyone of which if it is not sealed against the vacuum pad can prevent attainment of proper vacuum sealing on the rest. It is most common'to experience no less than 15 percent so-calledleaky (unseatedlslabs when said slabs, just resting on a vacuum pad, have normal texturing and/or sand finishes thereon. Manual seating of slabs which fail to seat isimpractical; can you imagine fifteen men each trying to locate two unseated slabs that he could get his hands on and exert up to 32 pounds downpressure on, at exactly the same time his fourteen helpmates were doing the same with'their 28 hands. This is no exaggeration, the present inventor has personally repeatedly failed to attain a vacuum seal with both of his hands pushing down on a slab when a test panel being set up only had a totalof ten facing slabs.

It is speculated that Kastenbein, of Tile Council of America, got by without seaters because he was primarily dealing with 4 inches X 4 inches quarry or bathroom tile, glazed in most cases, made under very controlled factory conditions where highquality control standards exist and where each and every tile is individually inspected for warpage-before being packaged.

SUMMARY OF THE INVENTION There is provided in accordance with the present invention a casting box having at least one vacuum line connection through its "floor with a laminated insert plate which includes a resilient upper layer provided with one vacuum line opening-for each slab, and which incorporates conduits extending from the openings to communication with the casting box floor. A place-.-

mentgrid having individual cells for receiving individual slabsis received in the casting box on the insert plate upper layer. After a slab has been placed in each cell a heavy seater is lowered onto the slabs to force them into sealing contact with the insert plate resilient upper layer and a vacuum is drawn through the casting box floor to hold the slabs so tightly against the insert plate resilient upper layer that the layer bulges up between adjacent slabs. The seater is removed; then the placement grid is withdrawn with the assistance of removable lateral shims and a settable composition such as concrete is poured into the casting box upon the slabs. The panels so formed have slabs set therein with simulated semi-flush concave joints. A 'modified device for production of panels faced with slabs on both sides is also disclosed.

The teaching of the present invention makes possible the rapid and reversible conversion of present day unfaced casting beds and forms to faced casting beds and forms with practically complete utilization of all components of the former and without in any way damaging said components or preventing their rapid change back to their original use. The vacuum plate inserts of the invention have such very limited unsupported spans that have to resist the forces generated by relatively high vacuum that relatively inexpensive inch plywood can be utilized as core plates, those having more than the needed strength required to prevent any undesirable flexure. Regardless of whether the vacuum bed covers 1 square foot or 200 square feet, the areas unsupported by sponge rubber sheet on either side of thevacuum plate inserts stay the same for any given facing material and are always minimal.

What must be done to a conventional precast concrete panel form to change from the manufacture of ordinary unfaced concrete panels to slab faced panels in accordance with the invention is to pad up the sides of the present casting boxes by an amount equal to the compressed thickness of the vacuum plate insert, normally about 1 inch, and drill'and tap the needed vacuum inlets in the base plates. The 1 inch thick shim strips can be inexpensively made of either wood or metal. Both vacuum plate inserts and shim strips need but minimal storage space when not in use, being storable on ends and edges, respectively. The tapped vacuum holes are easily and quickly plugged with cap screws of the-right length. In addition, using the vacuum system would require auxiliary equipment consisting of a suitable vacuum pump with a large accumulator, piping, valving, placement grid, or grids, and a seater, or seaters as described more fully hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS In The Drawings FIG. 1 is a schematic view of exemplary apparatus for carrying out the panel casting invention,

FIG. 2 is a top plan view of the casting box showing (proceeding leftwardly) successive stages in the casting of a brick slab-faced panel,

FIG. 3 is a longitudinal sectional view taken along line 3-3 of FIG. 2,

FIG. 4 is a vertical sectional view of an enlarged scale detail of the casting box showing the cap screw pressing against the grid which rests on the vacuum plate insert,

' FIG. 5 is a vertical sectional view of an enlarged scale detail of the casting box showing one right angle spacing washer fitted on the placement grid,

FIG. 6 is a vertical sectional view of the base plate of a modified, deep seater for seating brick slabs against the vacuum plate insert prior to pouring of the settable backing,

FIG. 7 is a vertical sectional view of a portion of a panel constructed in accordance with the principles of the invention and especially illustrating the concave joint simulations formed between adjacent slabs,

FIG. 8 is an end elevation view of a modified casting box for production of panels faced with slabs on both sides, and

FIG. 9 is a vertical sectional view of a portion of a panel constructed in accordance with the principles of the invention using the apparatus of FIG. 8.

DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS In the following description, to be read in conjunction with the drawings, reference is made to a particular example, used for illustration. Of necessity, the example includes brick slab sizes, joint simulation thicknesses and the like. Obviously the system may be used to manufacture panels of different sizes, thicknesses, joint types and sizes, using different slab material or sizes than those depicted and described, while making full use of the principles of the invention. Brick slabs is used herein to denote face brick, tile, thin brick, e.g., 1 inch thick, cut slate, and similar wall construction materials.

Referring to FIG. 1, a panel casting system 10 is shown including a casting box 12, which receives a vacuum plate insert 14, upon which brick slabs B are placed face down using a removable placement grid 16 to achieve conformity to the desired array pattern. The slabs are sealed against the vacuum plate insert with the aid of a heavy seater 18, a vacuum is drawn through the vacuuni 'plate insert 14 to maintain the slabs sealed against the insert and to elastically distend the insert so that it bulges up between adjacent slabs. Concrete or other settable backing C is then poured into the box over the slabs, screeded off and allowed to set. The panel P, when removed from the box' includes a face F of brick slabs B provided with a simulation of semiflush concave joints J between adjacent courses of slabs and between adjacent slabs in the same course.

Assume that a inch jointed, running bond J is-desired and that the brick will average 8 inchesin length and 2 A inches in face height.

Further assume that the desired panel P is to be independent and approximately 8 feet 6 inches in height and 10 feet 0 inch in width, X (2 A inches as inch) it; inch determines that our panels would be I02 34. inches, or 39 courses high, (39 (2 inches inch) inch) and 117 it; inches or l4 br'ick wide, (14 (8 inches as inch) inch).

Anfindependent panel is'one that is complete by itself, one that does not have to carry on joint work that was started in a previous panel, or one that is initiating joint work that its adjoining panel is to carry on with. An independent panel using inch joints is it; inch higherand it: inch wider than a carry on panel and it; inch wider than a starter panel as its brickwork is completely surrounded by inch joints, not just on one side or just on either the top or bottom, but on both.

The form cavity 20 in the casting box 12 for this panel will be the exact required dimensions, namely,

102 inches by 1 l7 /8 inches. Assume that these panels P are to be made in a precast plant which has casting table 22 (casting box floor), some 150 feet in length, 10 feet wide, equipped with steam coils, hydraulic tipping devices and vibrator hangers its entire length, and that it is serviced by several 20 ton overhead cranes. Further assume that the production schedule calls for the production of four panels per day. Four sets of casting box sides 24 of the required height to match the thickness of the desired panel P plus the depth taken up by the vacuum pad insert 14 would be set up to contain the 102 inches X l 17 inches outside dimension of the brick faced panel P.

The vacuum pad insert 14 basically includes a flat inch, V2 inch, or We inch steel plate, or inch, /2 inch, inch or inch sheet of plywood 26 cut to an exact 102 inches X I17 inches, minus 1/32 inch all around. Each half and each full brick slab B to be used on the bottom face F of these panels P is laid out on this insert 26 and on the geometric center of each is drilled a 7/16 inch hole 28 through the sheet 26, (one that could be tapped out to k inch for fill in" purposes later on if required, or for the insertion of lifting eyebolts).

Around the bottom edge of this vacuum plate insert is glued 2 inches wide X inch thick strips 30 of medium sponge rubber. Also on roughly 5 inch X 4 inch centers, 4 inch by 3 inch pads 32 of the same sponge rubber are glued but not to cover the vacuum access holes 28.

To the top side of the vacuum plate sheet 26 is glued a complete covering 34 of inch closed cell sponge rubber sheeting which has previously had slot cutouts 36 made in it to match the 7/ 16 inch holes provided in the steel plate or plywood sheet 26. These cutouts are approximately inch X 5 inches for each full brick and are set on the geometric centers of where these are to be located, and inch X 2 inches for each half or header brick, also on the geometric centers of where these are to be located.

The casting table bottom plate 22 is drilled and tapped at 38 for several vacuum lines 40, all of which spread out from a single fast action control valve 42.

The vacuum plate insert 14 with its sponge rubber borders 30, pads 32 and covering 34 is lowered into the form cavity 20 where it seats itself on the casting table bed plate 22. 4

The vacuum plate insert 14 is not only one of the keys to system l0s success, but it makes vacuum gripping practical for the first time. As conceived and practiced, vacuum can be applied to an unlimited area without creating even a semblanceof warpage or strain on the containing surfaces. The bottom rubber backing strips 30 and pads 32 absorb the forces which might otherwise be spent in warping or buckling any or.all containing surfaces.

The vacuum plate insert 14, because it is an independent unit, and a relatively cheap one, that can be fabricated in just a few hours, is one key to a versatility that can be extremely beneficial. Such vacuum plate inserts 14 can be used with practically any and all of the conventional casting beds 12 now in existence, which means that established panel producers can change over to the system 10 at a very minimum of expense.

casting table and the brick while communicating vacuum from a few locations in the casting table, to the lower face of each brick to pull each brick so tightly against the insert that (a): the inserts upper spongy layer bulges up in a bevel between adjacent brick and prevents panel backing composition from running under the brick to spoil what will become the panel face F.

The remainder of the vacuum generating system shown in FIG. 1 is made up of standard elements which are believed adequately explained by captions in the figure. The system benefits from the use of a relatively large accumulator 44, so one can use a reasonably sized vacuum pump 46. The accumulator allows one to exhaust all the lines and the open areas of the vacuum plate inserts almost instantaneously without but a very small and easily acceptable loss in the degree of vacuum held as a minimum.

While the system 10 has an overall seater 18 weight of pounds per brick equivalent, certain rough faced slabs may require up to 55 pounds in order to effect aperfectly tight seal with the insert face 34. Thirty inches of vacuum will produce the equivalent of about 60 pounds per 2 l inches X 8 inches brick face, but for acceptably reliable commercial production it takes the combination of the seater 18 weight and the initial vacuum grab through the insert 14 to attain the needed gasketing of the brick to the insert.

The step following installation of the insert 14 in the casting box 12 is installation of the placement grid 16, which is lowered down onto the top of the sponge rubber top covering 34 and which contains positive locating edges for all the full and half slabs B needed to face the panel P. This grid is preferably constructed so that all of its locating surfaces are to the left and to the bottom. The grid 16 itself preferably offers a reasonable clearance for each brick to be inserted in its cells 48. Thus, if the grid is made of A inch X if inch horizontal and Ya inch X if inch vertical cold finished bars, the space available to insert 2 inches X 8 inches brick slabs is 2 inches X 8 54 inches which covers very wide size variations among the individual brick.

Laborers next till all the grid cells 48 with brick B and while doing so shove each slab to the left as far as it can go and downward toward the bottom grid member in the same manner.

The grid 16 should be about one-fourth inch less in height than the thickness of the slabs B to be used. Thus, a grid for 1 inch thick slabs should be threefourths inch in height. Slabs should stick up above grid one-fourth inch, so that a sponge rubber lined, flatbottomed seater 18 can effectively contact the backs of the slabs and yet miss the top of the slab locating grid 16. The A inch differential cannot be increased very much without the possibility of ending up with the grid being locked in place by slab edges, that, due to slab deformities or tilt, just slightly overhang the ribs of the grid. It would, for instance, probably be impossible, a significant percentage of the time, to remove a inch high grid in use with 3 inches high full size brick even with the float provision later described herein.

Regular vertical grid ribsshould not exceed A: inch material unless very, very uniform sized slabs are going to always be. available. By using :4; inch material, the length of the grid void spaces will be A inch greater than the nominal length of the slabs, inch joint assumed and 8 inches long brick if; inch :6 inch),

which makes possible the use of considerably overlength slabs as well as providing extra removal clearance.

One-fourth inch stock can be generally used for horizontal grid ribs 52 for brick slab heights rarely vary even 1/16 inch over average size. A Va inch, inch 54; inch assuming the use of a inch joint), normal clearance rarely causes either slab placement or grid removal problems.

Regardless of the differential in height of the ribs of the locating grid and the thickness of brick or slabs being used, it is always desirable and often necessary to provide a releasing mechanism for the placement grids, after a vacuum seal has been attained on the brick or slab faces, if one is to easily and freely lift out said placement grids as is necessary prior to pouring the panel. When the bottom surface of the seater contacts the exposed back surface of each and every brick or slab and then transmits to each brick or slab some 2 pounds plus per square inch of downward pressure, (as the seater assembly comes to rest), the faces of the slabs or brick are forced downward, not only insuring a sealing contact with the top soft rubber lining of the vacuum plate insert, but also in an unescapable per-- centage of the brick involved, creating substantial contact between either or both of the brick or slabs vertical edges that were initially, (at the time of placement), in just very light contact or just adjacent to vertical edges of a placement jig. Since all brick or slabs are initially positioned in the oversize jig openings in a common manner, generally to the left and downward, rather substantial pressures can be built up in those directions with the resulting locking in of said placement grids against the adjacent two sides of the casting box. The subsequent application of vacuum generally takes over this created friction and maintains same as long as the vacuum is left on.

Removable Vs inch flat metal spacers do provide a means of freeing grids from 'the two-way build up of side pressures by releasing the grids and allowing them to be lifted out without difficulty. Such flat spacers, however, can present their own removal problems. If these flat spacers do not protrude up and above the sides of the molds a sufficient distance to allow them to be firmly grasped by hand or with pliers or other suitable tools, they, themselves, can be extremely difficult to remove. If they do extend up above the casting box sides for easy insertion and removal, then they can be easily hit by and badly damaged by the heavy seaters as they are swung into place and lowered down into the casting box. One-eighth inch flat steel strips cannot stand up to a swinging mass weighing up to five tons or better. Thus, the alternate use of screws to make possible an easy and positive way to exactly locate and then later release placement grids is the preferred means.

On those two sides of the casting box, corresponding to the two directions in which the brick or brick slabs are placed in contact with the edges of the placement jigs cavities, one provides, at properly spaced intervals, tapped holes at an elevation equal to the midpoint of the placement grids frame members. Into these tapped holes are inserted cap screws of such a length that their heads seat after the opposite ends protrude an exact one-eighth inch. This procedure eliminates any damage being caused to the placement jig by overtightening of the spacer screws and makes their thread-in practically foolproof for even the most inexperienced workman. A

further safeguard can be incorporated which insures that the cap screws can only be withdrawn the exact amount needed to leave their ends flush with the interior sides of the casting box.

If all slab placements are to be made to the left of respective grid cells, then with a inch joint being sought, one can use as inch outside vertical edge ribs 54. However, to avoid possible lock-ins, it is much preferred to use A inch stock in conjunction with easily installed or removed is inch spacers 56 (FIG. The use of such spacers permits one to attain the equivalent of zero installed clearance between the sides of the jigs (placement grids) and the sides of the casting form, thereby insuring correct and thus reproducible slab placement as well as providing a means of attaining some side to side and top to bottom float after the slabs have been gripped, by removing the spacers.

Again assuming that inch joints are called for, then one using spacers, would need inch spacers 56 to space out the placement grid from the bottom vertical side of the casting form if the recommended is inch material was used, (V4 inch is inch it; inch). The use of the 1% inch spacer here provides the means of obtaining top to bottom float once the slabs have been seated and vacuum-locked in place.

This float is achieved by use of left vertical and bottom horizontal ribs with spacers 56, and is one 'of the real keys to most. successful use of the locating grids. Preferably the spacers 56 are in the form of short L shaped channels'removably received in slots 57 formed in the top and exterior of the left-most and bottom outside grid elements. The float one obtains in both directions not only makes it possible to lift out the grid prior to pouring, but to do it easily, even in spite of the tilt and slab deformity problems that generally exist.

If it is not already apparent to those reading this specification, it should be pointed out that verticalf? horizontal, top and bottom are sometimes used herein 'to denote orientations which would be correct for the casting systemonly if it were tilted up to match the orientation of the panel P when the panel becomes part of a wall. Actually, of course, the casting is usually carried out horizontally. Thus the terms are used in the sense of convention, and not necessarily in the sense of actual spatial orientation.

The flush concave joint I that is obtainable with the system 10, is of course a result of the high vacuum employed creating sufficient pull to displace a sufficient amount of the vacuum plate insert sponge rubber facing 34 and causing same to bulge into the void joint areas to give a concave outline in the same.

The typical slab placement grid 16 which provides two like edge contacts for each and every slab B is the ultimate. Any laborer, who places slabs in such a grid, does not have to waste any time or effort or exercise any special skill or judgment to properly adjust the spacing or alignment of any slab. All anyone has to do is place successive slabs in empty grid cells and to move each slab as far as possible to the left and keep same down adjacent to and in contact with the horizontal ribs. With this type of positioning grid one can easily set and position slabs even while blindfolded.

There are, of course, much simpler slab locating grids. The simplest grid has no intermediate vertical ribs. This grid would offer an edge locating surface for the lefthand starting b'rick'in each course, but the balance of the brick in each course would have to be spaced apart by eye." The chances are that one would most always find it necessary to make time-consuming lateral adjustments as each course has been filled with slabs, so as to better even up the width of the void vertical joint spaces. Grids have been made where the two outside brick of groups of three have positive locating ribs or pins which positively locate them, leaving only each center brick to be centered in the void space by eye. This system is quite effective when the slabs rest on or are only slightly embedded in fresh mortar. Under such conditions the slabs themselves are floatable in that they offer but very slight resistance to the very slight displacement that may be necessary to free a lock-in of the grid. When the vacuum gripping system 10 is used, the slabs are just about unmovable, and grid lock-ins can be real serious. If there are any projections of slab edges over both left and right vertical ribs, then the grid just cannot be lifted out. Any built-in float produced by the use of spacers, or other means, is simply ineffective in such a situation. Removable float producing spacers 56 can only be effective when slab contact with vertical ribs is either always to the left, (or to the right, if the spacers are positioned to the right), and when slab contact with the horizontal ribs is always at the bottom, (or to the top if the spacers are positioned at the top). Float can only be effectively achieved when slabs and spacers are so located that the removal of the spacers automatically makes it possible to shift the grid horizontally and vertically so that it at once loses contact with the slabs and is therefore verti cally removable with ease.

Slab locating grids can also be more economically constructed if simple short pins are substituted for complete vertical ribs 50. It is a relatively simple. task to gang drill and then machine tap required holes for such locating pins which are threaded on one end.

Slab locating grids per se have been used for many years for slab placement purposes by others. The use of spacers, whether they be actual shims that are inserted between the sides of the panel form and the slab locating grid or threaded bolts 56' (FIG. 4) that are screwed in threaded openings 58 in the appropriate form sides to produce and maintain desired clearances, is believed to be an innovation. Up until the advent of the vacuum gripping system 10 for slab position retention, the need for float creation could not have been fully appreciated.

The next operation following placement of the brick slabs in the grid cells 48 is to lower down onto the backs of all the brick B in the individual cells 48 the seater 18 having a flat pad 60 that is just a bit smaller than the panel to be poured and having a semi-soft rubber facing 62 and having a fairly equally distributed weight equivalent of about 25 pounds per full brick in the panel. It has been found that even soft sponge rub ber if used for the inserts or face 34 offers enough deformation resistance to prevent thet gross weight of a rough faced brick or brick slab from making a usable seal, that is, make enough of a seal with the vacuum plate insert 14 to permit .a vacuum to be readily achieved. r

When relatively thin brick slabs are to be used as facing material, it is necessary that the seater 18 have on its base side protruding and spaced pads 60', each faced with suitable sponge rubber facings 62'. These pads should be at least one-half inch smaller both ways than the slabs they will contact and preferably about as thick as the grid is high. This is necessary so that the seater can contact each and every slab even though that slab actually is only as little as one-third in thickness, the depth of the grid opening.

The seater 18 is preferably a heavy, cast, cranemovable body as depicted in FIG. 1, but the pad 60 and facing 62 could be provided on a ligher element constructed to be forced down against the slabs, for instance by hydraulic ram means.

Once the seater has weighed upon the slabs, the vacuum valve 42 is opened, and the slabs B are literally grabbed by the vacuum.

When panels are being faced with very thin and therefore quite fragile brick slabs and/or very rough faced slabs, some minor problems may be experienced with vacuum leaks. By arranging the vacuum plate inserts support layer of sponge rubber, so as to divide up the panel s exterior face into several more or less equal divisions areawise, and by separately piping gauged vacuum lines with individual valves to each such division, one can easily and quickly pinpoint where a broken or impossibly rough faced slab or slabs are located. The faultless sections can be held on vacuum while the troublesome area is shut off, the seater raised out of the way, the faulty slabs replaced, the seater returned and the vacuum again turned on. The seater 18 is then raised and carried over to the next panel (if an assembly line operation is being employed) or put in storage. The incipient panel is next checked for brick alignment, the grid 16 removed, and the panel backing then poured, screeded and finished. The backing may be any conventional settable construction material such as cement or a synthetic plastic substitute.

Because of the simplicity of changing vacuum plate inserts, grids, and seaters, the system lends itself to rapid production changes, and if the runs are long enough, then the labor savings involved ivill easily pay for extraexpense involved with the necessary tooling up.

The joint work with the system 10 is superb, and the panel faces come out beautifully clean and unmarked, as there is no leakage.

While the seater may be the simplest unit in the system 10 of panel making it is nonetheless important. Without a seater it is doubtful one could ever get a 4 feet X 8 feet, or larger panel '5 complement of slabs sufficiently in contact with the foam rubber surface of a vacuum plate insert to create a vacuum seal excepting when uniformly smooth, probably glazed, slabs are used. A seater 18 actually takes the place of hundreds of non-existent hands, without which the system 10 would be impracticable. for use with most slabs.

A typical closed cell sponge rubber to use for the sponge rubber layers of the vacuum plate insert and the seater is manufactured by Rubatex.

Although it is intended that the casting box be used horizontally, it may be tipped to an upright condition during the panel manufacturing process, for instance to facilitate removal of the completed, hardened panel.

It should be apparent that, prior to hardening of the panel backing composition, the upper (rear) surface of curtain wall may be provided without departing from the essential characteristics of the invention.

Several of the popular brick-faced panels now being extensively used in Europe are basically just a single brick width wall, the equivalent to our present hand laid veneer walls. A few such panels are laid up by hand, under favorable on the ground conditions, in some cases under cover and by one system up against tilted in and coursemarked back-up forms. Other single brick width panels are top poured, the individual brick being preset, dry, face down into precise rub her or metal templates with the void joint spaces then being filled with a very fluid grout.

Several years ago a Texan tried to promote a vertical poured vacuum held single brick width panel. That system not only furnished excellent and perfectly clean exposed joint work, but also included the ability to incorporate both vertical and horizontal steel reinforcing, a very valuable option. However, the costliness of the casting forms and other economic factors doomed the efforts to commercialize that system.

Both the European and American brick manufacturers, for obvious reasons, would like to see whole full size brick incorporated in so-called brick faced panels in preference to thin brick slabs,even though the latter obviously offer some cost savings. Eventually the cost factor will likely cause most faced precast panels to utilize brick slabs, for concrete per cubic foot will always be substantially lower in cost than an equivalent amount of brick. However, there may be, for some time at least, a substantial'market for single width (3 k most of the economically producible single width brick the panel may be decorated by partly embedding decorative material such as marble chips, brick slabs or the like in the setting backing composition. Furthermore, conventional reinforcing rods including protruding attachment eyes for installing the panels as a building panels that have been or are in production today. In the first place, not one of such top poured panels being made today has a quality of workmanship on exposed brick faces that would be acceptable to most buyers in this country. The second important fault of practical contemporary single width brick panels is that not one of them can be economically reinforced with both horizontal and vertical reinforcing steel. Any single width brick wall that is held together with ordinary mortar, that has to be transported from plant to job site, that has to be hoisted into place, and that finally has to be capable by itself of withstanding hurricane force winds, must be reinforced with steel. In addition, a reinforced single brick width wall at once changes classification from non load bearing to load bearing. When insu lation is not important, this load bearing feature can be very important. A reinforced 3 it inch brick panel can under many such conditions replace 'an 8 inch wall. Three and three-fourth inch thick reinforced brick panels that have tested out real well have, for example, utilized inch round reinforcing steel on approximately horizontal and vertical ,16 inch centers with no ties.

The system disclosed in this document is susceptible of modifications to make possible the economical precasting of reinforced single width brick panels, panels that also have top quality exposed jointwork. These are slight and very inexpensive modifications.

To most effectively reinforce any masonry panel, the steel rods must be positioned in roughly the center of the panel thickness and, of course, be completely, em-

bedded in the mortar used. To get such rods in the center of a single width brick panel, one must use so-called cored brick, prefrably the three hole type for 8 inch long brick and fiveholes for 11- ii; inch long brick. The round core holes in such brick are about 1 inch in diameter' and always have one such void at the midpoint in each brick horizontally and vertically. The 1 inch diameter of such core holes insures both the easy threading of 54 inch round steel through multiple courses top to bottom of a panel and the total encasement of the steel in mortar of more than sufficient thickness around same.

With normal is inch mortar joints, such as would be used on most panels, the use of V4 inch horizontal and vertical reinforcing steel can present some real problems. The average it inch total clearance can give some placement and positioning troubles unless the coursing is nearly perfect, the brick used on size and straight edged. Most any system with extra time, care, and top notch supervision can cope with the above, but the real sticker to date has been how to top pour reinforced single width brick panels, having is inch joints, using 1/4 inch round steel and ending up with full joints and with full utilization of the steel used. It is difficult enough to top pour single width brick panels without the most substantial blockage that A inch round steel, positioned half way down the joint cavity-offers. Even without reinforcing steel to contend with, the mortar used must be almost like thin soup, the brick must be pre-soaked to use up their powers of absorption, lest they prematurely dry up and thus stiffen any mortar that comes in contact with them before it has time to settle down into and fill the multiple inch 3 36 inch narrow and deep voids that joint areas consist of. Even if intense vibration is added to the above tricks-of-thetrade antidotes, onecould too often end up with serious unsightly void spaces that should have been full of mortar as well as with steel that is not able to do its job because it is only partially surrounded with mortar.

The modified casting equipment for producing reinforced panels is identical to that for the system as depicted with the exception of the bottom or top casting box side wall, which would, at appropriate points along its length, have inch holes drilled and be supplied with suitable flush plugs to fill said holes when they are not being used. The V4 inch round vertical reinforcing rods would be passed through these holes when being inserted into their respective vertical row of the bricks center core holes. These holes would be drilled on the center line of the vertical reinforcing rods location and have their centers 3/ 16 inch above the centers of the brick core holes the rods are to be enclosed in. The flush plugs will always be in place except when the rods are being inserted. All sides forthis type of panel casting box would, of course, be just high enough to allow the fresh concrete to be leveled over the top of the single brick, on edge and with the vacuum seal in effect. The casting box includes a level surface, the bottom of which would be piped at several locations to a common manifold the manifold would be capped on one end and fitted with a suitable valve at the other end this valve in turn would be piped to a suitably large vacuum accumulator tank which in turn would be piped to a vacuum pump of suitable capacity. Four side forms of sufficient length would be fastened to the base 6 plate so that their'interiors would enclose the exact area of the desired panel to be cast. The bottom or top side form would be suitably drilled and furnished with flush plugs for the insertion of the vertical reinforcing steel in between first and second pours. A suitable vacuum plate insert would be placed in the casting area.

The actual casting procedure would follow very closely that employed in system 10. Assuming that the casting box sides have been fastened down, (clamped or bolted), oiled, and the proper vacuum plate insert has been lowered in place; the following steps are car- 4. Open thevacuum line valve.

5. Remove the seater.

6. Remove the shims or withdraw the release screws and remove the locating grid.

7. Make partial pour of very thin mortar, preferably, in most cases, with vibrators attached to side plates turned on, up to a level approximately threeeighths inch below, the top of the brick core holes.

8. Remove plugs, one at a time, in side adjacent to panel bottom, (or top for that matter), and thread into the opposite alternating cor'e holes and vertical joint spaces V4 inch, (or other suitably sized), round reinforcing rods which had been precut to exact desired length.

9. Install sufficient hangers to hold these vertical reinforcing rods so that their tops are generally even in height with the midpoints of the bricks core holes. The reinforcing rods at this stage would be submerged in the mortar approximately oneeighth inch of mortar being over the tops of the rods.

10. If specifications call for wire tying of the horizontal and vertical rods together, one must at this time drape each vertical rod at the point same is going to be crossed by a horizontal reinforcing rod, (where a wire tie is specified). Draping simply consists of hooking a preformed wire tie down under the vertical rods, bringing the looped ends up and bending each one over the corners of its brick on opposite sides of the joint void into which the horizontal reinforcing rod will be inserted.

ll. Install pre-cut to length horizontal reinforcing rods by dropping same in their respective horizontal joint cavities, and, if necessary, pushing them down in the mortar until they contact and rest on the tops of the previously installed vertical rods.

12. If wire ties were called for and draped prior to placing the horizontal wires, then they would be twisted up tight at this time with a regular wire twisting tool.

13. Balance of the pour would next be carried out, and the top exposed surface brushed or screeded as called for.

14. As soon as the mortar has set up sufficiently .the sides can be removed, the vacuum shut off and released.

Referring now to FIGS. 8 and 9 of the drawings, a

variation of the casting box is shown for use in fabricating panels faced with slabs on both sides. For equivalent parts, numerals as used in connection with parts described in connection with FIGS. 1-7 are used.

To explain most succinctly, the system uses two casting boxes 12 hinged together at one edge. Each of these is provided with a vacuum plate insert 14 and a placement grid 16 and releasing means exactly as explained in connection with FIGS. 1-7; brick slabs are placed in all of the placement grid cells of both casting boxes, seated using two seaters 18 (or the same seater l8, successively) and a vacuum drawn through the casting boxes to maintain the brick slabs gasketed against respective vacuum plate inserts and the inserts uppermost resilient covering 34 bulged up between adjacent slabs on each vacuum plate insert; the seaters are removed; the placement grids are released and removed, only then does a significant divergence in method occur. The two casting boxes are folded up to verticality i.e., until their formerly upper edges engage all the way around and lock together. Then a fluid, hardenable composition is poured into the mold so created and allowed to harden. The vacuum is then released and the mold opened to provide a two-faced panel with semi-flush concave joint simulations as shown in FIG. 9.

Since the casting boxes 12, vacuum plate inserts,

ods. System 10 is an answer to the demanding need of a method that will permit facing of both sides of individual panels with the ease, quality of jointwork and clean faces that can be achieved with system 10' for single faced panels, (vacuum gripping and top pour).

Basically the equipment needed to use this alternate system 10 is a pair of horizontal, opposed and hinged precast panel forms 12 that are fitted with suitable vacuum plate inserts 14, along with matching slab placement grids 16 with releasing shims or screws, an appropriate seater 18, and a vacuum pump (FIG. 1) 46 with a large accumulator 44. The three containing sides 24 of each casting form would generally be of a height that would equal the thickness of the vacuum plate insert 14 when under vacuum, plus one half the desired thickness of the panel to be poured. Thus, if the vacuum plate insert 14 under vacuum is 1 inch thick and the panel is to be 8 inches thick, then the form sides 24 should be 5 inches high. Two such panel forms when faced with brick, placed under vacuum and as described in relation to FIGS. 1-6 tilted about the'hinges 66 into vertical, wall-edge to wall-edge contact and in perfect alignment as shown in full lines in FIG. 8 create a combined vertical pour form. Once this assembly has been properly clamped or bolted together, e.g., utilizing the clamps 68, it can be very easily filled with fluid mortar through open top 70 to form a panel that is faced on both sides with any desired material (FIG. 9), one that has superb exposed joint work and one whose faces'generally come free from the casting forms 12 clean as a whistle. Further, by having the base channels 24, when being tilted into pouring, position, come to rest on a suitable heavy base beam 72, which in turn is resting on a suitable gang roller 74, one provides the means to move a curing panel axially along the track plate 76 to one side long before it could be safely picked up, thus making the casting forms available for reuse much, much sooner than they would normally be available possibly doubling or even tripling their productive capacity. This alternate set-up can thus provide the means for most economically producing two faced panels using slabs of just about any thickness that have very wide size variations, almost the greatest of face deformities, in any desired pattern or bonding and with the most popular flush concave joints. In combination with fast setting mortars, this alternate can at least double output per square foot of building space consumed from that achievable with other systems. Labor reaches a high level of utilization because all the advantages of cleaning, set up, slab placing, etc., is done on the ground in a horizontal position while the pouring is done in vertical position with its sizable reduction in exposed surface.

Assuming that the previously poured panel has reached a curing stage that would permit removal of the hinged base plates,

1. Remove cap screws from exposed backs of base plates that hold 5 inch side and bottom channels in place.

2. Remove master clamps that have held the opposing form assemblies tightly in contact with each other.

3. Lower sides, which have vacuum plate inserts thereon, to a horizontal position.

4. Clean off vacuum plate inserts and areas surrounding same to which the channels 24 are bolted.

5. Bolt down another set of bottom and side channels 24 and oil their faces.

6. Place slab placement grids in position and place spacers in position.

7. Properly fill grids with face down slabs.

8. Bring seater over and down onto backs of slabs.

9. Turn on vacuum to each side 12 as it is ready.

10. Remove seater and then the grid.

11. Remove base bolts that fastened adjacent side channels together, (which surround previously poured panel).

12. Remove these side channels.

13. Slide this still curing panel to one side out of the way thus also towing into position an attached alternate base support channel 72 on its own rolls 74.

14. Tip up the hinged forms into contact with each other and bolt adjacent vertical side channels to each other.

15. Place main holding clamps in position and tighten same.

l6. Pour mortar through open mold top and screed.

17. At proper time lift up and carry previously poured panel to storage thus freeing the base channels on which this panel was resting as well as the base support channel and its rolls for reuse.

It should now be apparent that the method and apparatus for casting slab-faced panels as described hereinabove possesses each of the attributes set forth in the specification under the heading Summary of the Invention hereinbefore. Because the method and apparatus for casting slab-faced panels of the invention can be modified to some extent without departing from the inserting a placement grid having a plurality of slabreceiving cells in the casting box;

inserting a brick slab in each placement grid cell;

mechanically seating all of said slabs against the resilient gasketing material by concurrently exerting a greater than atmospheric pressure downward mechanical force on the uppermost, backside of all of said slabs;

drawing a vacuum through said gasketing material to maintain the slabs in sealed contact with the resilient gasketing material and to so resiliently compress the gasketing material that it bulges up between adjacent ones of said slabs;

terminating exertion of said downward mechanical force;

removing said placement grid from the casting box;

introducing a hardenable fluid backing composition into the casting box upon the slabs and spreading the composition therein to integrate the slabs into;

a panel having the lowermost sides of the slabs as a facing and to produce semi-flush concave joint simulations between adjacent ones of said slabs; allowing the backing composition to harden; terminating said drawing of vacuum; and removing the slab faced panel from the casting box. 2. The process of claim I wherein each slab is rectangular, each placement grid cell is rectangular and slightly larger than each slab in horizontal dimensions;

wherein the placement grid is slightly smaller in horizontal dimensions than said castin box; wherein the step of inserting the placement grit? in the casting box includes shimming the placement grid against two adjacent sides of the casting box to preclude lateral movement thereof; wherein the slab inserting step includes placing the same two adjacent edges of each slab in contact with the same two adjacent edges of each respective placement grid cell; and wherein the placement grid removal step includes: discontinuing shimming the placement grid against the casting box two adjacent sides, shifting the placement grid laterally towardat least one of the casting box opposite two adjacent sides, and then lifting the placement grid free of the casting box. I

3. The process of claim 1 wherein the stepof mechanically seating includes applying a downward force of at least 25 pounds per 2 V4 by 8 inch brick equivalent to each slab.

* i II

Claims (3)

1. A process for manufacturing slab-faced panels in a horizontal casting box having a floor provided with a covering of resilient gasketing material, and peripheral sidewalls, comprising: inserting a placement grid having a plurality of slab-receiving cells in the casting box; inserting a brick slab in each placement grid cell; mechanically seating all of said slabs against the resilient gasketing material by concurrently exerting a greater than atmospheric pressure downward mechanical force on the uppermost, backside of all of said slabs; drawing a vacuum through said gasketing material to maintain the slabs in sealed contact with the resilient gasketing material and to so resiliently compress the gasketing material that it bulges up between adjacent ones of said slabs; terminating exertion of said downward mechanical fOrce; removing said placement grid from the casting box; introducing a hardenable fluid backing composition into the casting box upon the slabs and spreading the composition therein to integrate the slabs into a panel having the lowermost sides of the slabs as a facing and to produce semiflush concave joint simulations between adjacent ones of said slabs; allowing the backing composition to harden; terminating said drawing of vacuum; and removing the slab faced panel from the casting box.

2. The process of claim 1 wherein each slab is rectangular, each placement grid cell is rectangular and slightly larger than each slab in horizontal dimensions; wherein the placement grid is slightly smaller in horizontal dimensions than said casting box; wherein the step of inserting the placement grid in the casting box includes shimming the placement grid against two adjacent sides of the casting box to preclude lateral movement thereof; wherein the slab inserting step includes placing the same two adjacent edges of each slab in contact with the same two adjacent edges of each respective placement grid cell; and wherein the placement grid removal step includes: discontinuing shimming the placement grid against the casting box two adjacent sides, shifting the placement grid laterally toward at least one of the casting box opposite two adjacent sides, and then lifting the placement grid free of the casting box.

3. The process of claim 1 wherein the step of mechanically seating includes applying a downward force of at least 25 pounds per 2 1/4 by 8 inch brick equivalent to each slab.

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