US 3686817 A
Precast wall units having full height dovetail edge grooves which align with similar grooves on adjacent units to provide full height keyways. Sheet metal keys are wedged within the keyways and lock the adjacent units together, the joint being completed by the introduction of reinforcing rods and grout.
Description (OCR text may contain errors)
United States Patent Adams  PRECAST WALL CONSTRUCTION  Inventor: Richard W. Adams, P.0. Box 4,
Loxahatghee, Fla. 33460 221 Filed: Dec. 15,1969
211 Appl.No.: 884,793
 US. Cl ..52/586, 52/438 [5 l] Int. Cl. ..E04c 1/10, E04c H30  Field of Search ..52/437, 438, 586, 241, 440,
 References Cited UNITED STATES PATEN'IS Glukes...; .....46/26 Aug. 29, 1972 2,363,233 11/1944 Dalton ..287/20.92 K 2,863,185 12/1958 Riedi ..287/20.92 K 3,160,249 12/ l 964 Pavlecka ..52/586 Primary Examiner-John E. Murtagh Attorney-Clarence A. O'Brien and Harvey B. Jacobson 7] A881 RACT Precast wall units having full height dovetail edge grooves which align with similar grooves on adjacent units to provide full height keyways. Sheet metal keys are wedged within the keyways and lock the adjacent units together, the joint being completed by the introduction of reinforcing rods and grout.
8Claims, IZDravvingFigures PRECAST WALL CONSTRUCTION The instant invention is generally concerned with precast wall construction, and more particularly with full height precast concrete wall sections and unique wedge-type keys for the rigid interlocking of the sections.
A primary object of the instant invention is to provide a wall construction system wherein precast full height wall units are provided in conjunction with means for interlocking the wall units in the formation of a continuous concrete wall in a simple and economical manner, without necessitating the erection of elaborate forrnwork as in the forming of a poured in situ wall or the time-consuming laying of block as in a block wall.
Another significant object of the instant invention resides in the provision of dovetail joining grooves and unique cooperating sheet metal keys which enable a rigid interlocking of adjacent wall units in a manner so as to permit the erection of large wall areas with only a minimum amount of temporary bracing prior to an introduction of the reinforcing rods and binding grout between the adjacent units.
Other advantages of the instant invention arise from the provision of a system wherein water-tight joints are provided between adjacent wallunits withthe unit joining and sealing mortar or grout being contained within the keyway defined between the adjacent units and not extending to the outer surfaces thereof, thereby avoiding additional joint finishing.
Basically, the objects of the instant invention are achieved through the provision of wall units consisting of full height precast concrete sections having hollow cores and dovetail vertical edge grooves which align with similar edge grooves on adjacent units so as to define keyways having opposed dovetail portions for the reception of wedge-type keys extending into and between the grooves and locking the sections together. The grooved vertical unit edges are, to the opposite sides of the dovetail grooves, beveled to the corresponding unit face so as to, upon the joining of two units, provide for a line contact between the units at the faces thereof and at. the same time define grout channels immediately inward thereof in direct communication with the corresponding keyway. Each key is formed of sheet metal and capable of being wedged into position, through either a tapered configuration to the keyway itself or through a selective expansion of the sheet metal key, depending upon whether the associated wall units are of mold cast construction or extruded construction.
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:
FIG. 1 is a perspective view of a section of a wall constructed in accordance with the instant invention;
FIG. 2 is an enlarged plan view of the adjoining edge portions of a pair of coplanar wall units joined in accordance with the instant invention; angularly joined wall units;
FIG. 4 is across-sectional view taken substantially on a plane passing along line 4 --4 in FIG. 2;
FIG. 5 is a cross-sectional view taken substantially on a plane passing along line 5 5 in FIG. 2;
FIG. 6 is a cross-sectional view taken substantially on a plane passing along line 6 --6 in FIG. 2;
FIG. 7 is an exploded perspective view of a unit joining key and the insertion tool therefor;
FIG. 8 schematically illustrates the mounting of one of the joining keys;
FIG. 9 is an enlarged vertical cross-sectional view through a completed joint;
FIG. 10 is an exploded perspective view of a modified fonn of unit joint key and the insertion tool therefor;
FIG. ll illustrates the mounting of the key of FIG. 10;
FIG. 12 is a cross-sectional detail taken substantially on a plane passing along line 12 -12 in FIG. 11.
Referring now more specifically to the drawings, reference numeral 20 is used to designate a precast masonry wall unit constructed in accordance with the instant invention. The wall unit 20, normally of a height equal to the desired height of the finished wall and a width of approximately 4 feet, is provided with a series of hollow full height passages or cores 22 defined by webs 24 extending between and integrally interconnecting opposed face panels 26.
The joining of the wall units 20 to each other is effected at the vertical edge portions thereof. Accordingly, each edge is provided with a full height joining groove or channel 28 therealong With reference to FIGS. 1 and 3 in particular, it will be appreciated that in the corner forming unit, designated as 20the groove at the edge which is to define the corner is actually provided so as to open laterally through one of the face panels for the joining of another unit at right angles thereto. In each instance, the groove or channel 28 is of a dovetail configuration, increasing in width inwardly from the mouth or outer end thereof. In the intermediate wall units 20, as opposed to the corner wall units 20the dovetail grooves 28 are aligned centrally along the vertical edges with the adjoining edges 30 of the face panels 26 each being beveled inwardly from the outer face of the corresponding face panel 26.
The groove or channel 28 at the corner forming edge of the corner wall unit 20' is inwardly offset from the extreme edge 32 of the wall unit a distance sufficient so as to define a flange 34 of a width generally equal to the face panel edge portion or flange which bounds the groove 28 associated with an edge of an intermediate panel 20.
Each of the cores 22 and edge grooves 28 are internally tapered along the full height of each wall unit 20 and 20'that is the internal faces which define the individual passages and grooves converge slightly toward each other from the upper end of the corresponding unit to the lower end thereof. This taper, in addition to facilitating the removal of the internal formwork when the unit is formed in a casting mold, is particularly significant in the joining grooves or channels28 in that the taper specifically cooperates with the sheet metal keys 42 in effecting a positive interlocking of adjacent units, as shall be explained subsequently.
In joining adjacent wall units 20 and/or 20the grooved edges thereof are positioned against each other with the grooves 28 in alignment so as to define a double dovetail keyway having opposed grout channels 44, defined by the beveled edges 30, tapering outwardly to the contacting face edges which close the internal keyway and communicated grout channels and form a substantially continuous wall face. The adjoining edges are rigidly interlocked by the introduction and wedged engagement of a pair of the sheet metal keys 42 within the formed keyway. Each of the keys 42 includes a top plate or panel 46 configured so as to conform to the double dovetail configuration of the formed keyway at a specific height along the tapered length thereof. In other words, the plate 46 includes a pair of opposed parallel straight edges 48 interconnected by side edges 50 tapering inwardly from the ends of the opposed edges 48 to a common reduced width center line. Depending flanges 52 are integrally formed with and provided peripherally about the plate 46 and act so as to guide and stabilize the key 42 during the introduction thereof within the corresponding keyway. Finally, the key plate 46 is provided with an enlarged central rectangular aperture 54 therethrough which provides a means for the introduction of one or more reinforcing rods 56 and a free flow of the grout or mortar 58 utilized in effecting a waterproofing and final locking of the joint.
' It is contemplated that keys 42 of two different sizes be provided, one, the narrower of the two, being of a size so as to slip freely through a major portion of the heightof the keyway and wedge therein toward the lower end of the keyway, and the second key 42 being of a size so as to wedge within the keyway toward the upper end thereof, thereby providing spaced wedgetype locks.
The mounting of the keys 42 is effected by utilizing a tool 56 consisting of an elongated rod 58 having a flat plate 60 mounted on the lower end thereof, the plate in turn having a pair of downwardly diverging flat flexible tabs 62 thereon. The tabs 62 are biased together and inserted through the key opening 54 so as to engage the tool plate 60 against the key plate 46, the plate 60, as will be best appreciated from FIG. 8, being smaller than the plate 46 so as to not interfere with the wedging action thereof. The tool and mounted key 42 are then lowered into the keyway down to the point at which the key 42 comes into wedging contact with the keyway. At that point, the upper end of the tool rod 58 is given a sharp blow so as to permanently wedge or set the key 42 in position, after which the tool 56 is merely pulled upwardly so as to snap the tabs 62 out of the key opening 54. This process is used for both the upper and lower keys.
Once the keys 42 are set, the adjoining wall units are rigidly interlocked and the wall sections substantially self-sustaining, requiring only a minimum amount of bracing. The actual joint is completed by the introduction of one or more reinforcing rods 55 through the aligned keyway openings 54 and a subsequent filling of the keyway with grout or mortar 57 which completely fills the interior of the keyway and grout channels 44 and forms a water-tight permanent joint. It will be appreciated that the contacting edges of the faces of the face panels retain the mortar within the keyway and grout channels 44 and eliminate the necessity of finishing the exterior of the joint. The provision of the grout channels 44 facilitates the flow of the grout so as to completely fill the keyway, and at the same time provide for a more complete bonding of the adjoining panel edges to each other across the full depth thereof.
Incidentally, noting FIG. 9 in particular, it is contemplated that the wall units 20 be set on an appropriate foundation 64, for example a poured concrete footing, from which inwardly projecting embedded dowels 66 extend. The dowels 66, formed of reinforcing bars or the like, are so orientated so as to project into the lower end portions of the keyways formed by the standard width units, thus providing an alignment means for the wall units and a means for effecting a positive bonding of the wall units to the foundation 64. Once the poured grout has been vibrated or otherwise compacted, the tops of the aligned units are now ready to receive a reinforced concrete beam, cap, or slab, or other appropriate construction.
With reference to FIGS. 10, 11 and 12, the instant invention also contemplates the provision of precast wall units 68 wherein the joining edge grooves or channels 70 are of a constant cross-section throughout the length thereof, that is not tapered along the length thereof in the manner of the grooves 28. such units 68 enable the utilization of an extrusion process in the forming of the units, the individual units being cut to length by an appropriate masonry saw or the like from the section being continuously extruded.
In order to lock these units 68 together, a modified key 72 is required. This key 72 differs basically from the key 42 in that the top plate or panel 74 thereof is centrally folded, thereby reducing the width thereof so as to allow for a free slipping of the key 72 within the formed keyway to the desired height. Upon being properly located within the formed keyway, the key plate 74 is forcibly straightened. This effecting an expansion of the key 72 into locked and locking engagement with the opposed dovetail grooves 70 which define the keyway. Once the key 72, or more particularly a pair of the keys 72 are locked into position, the adjoining wall units 68 are rigidly locked together so as to form a closed grout receiving keyway having full length lateral grout channels 76 between the keyway and the engaged and joint closing outer faces of the adjoining wall units, thereby providing a sealed joint.
The actual manipulation of the modified key 72 is effected by a tool 78. The tool 78 includes an elongated rigid tube 80 mounting a plate 82 on the lower end thereof, the plate 82 being provided with four radially projecting upwardly angled rigid tabs 84. A collar 86 is slidably mounted on the plate secured tube 80 and in turn mounts a pair of diametrically opposed downwardly arcing forming plates 88. An elongated rigid rod 90 is slidably received within the tube and mounts a pair of diametrically opposed projecting lugs 92 on the lower end thereof which extend outwardly through a pair of vertically elongated slots 94 in the tube 80 for engagement with the upper end of the plate mounting collar 86. In use, the lower plate 82, with the tabs 84 thereon, is introduced through a cross-shaped opening defined within the key plate 74 and rotated approximately 45 degrees. The key 72, mounted in this manner, is then lowered to the desired position within the double dovetail keyway, after which the arcuate collar mounted plates 88 are, through the rod 90,
forced downwardly while the plate 82 and tabs 84 are drawn upwardly by means of the tube 80. Continued pressure by the opposed members on the key plate or panel 74 effects a straightening or flattening thereof into positive wedging engagement with the opposed dovetail grooves 70 so as to effect a positive locking of the adjoining units 68 to each other preparatory to the introduction of the grout and reinforcing rods. Once the key 72 is locked into position, the tool 78 is rotated so as to align the tabs 84 with the openings provided therefor, and the tool 78 vertically withdrawn from the keyway.
From the foregoing, it will be appreciated that a highly unique construction system has been defined wherein full height precast wall units are utilized in conjunction with connectors for interlocking the wall units into a substantially free standing wall area for the subsequent reception of rigidifying rods and mortar. The unit interlocking keys are received within keyways defined by opposed dovetail grooves provided on the adjacent abutting vertical edges of a pair of adjacent,
wall units the dovetail grooves and adjoining edge surfaces being so configured as to define-both the keyway and a pair of adjacent grout channels, inconjunction with contacting face edges which completely seal the joint so as to preclude any leakage of the poured grout therethrough, thereby providing a finished joint requiring no troweling or the like. It should be appreciated that each of the keys utilized in the instant invention completely fills the keyway and, upon being wedged into position, contacts the keyway completely thereabout and provides a rigid stable interlock. Further, it will be noted that the system of the instant invention is self-supporting, requiring no structural steel columns, beams or the like for support.
The foregoing is considered as illustrative only of the principles of the invention. Further,since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
What is claimed as new is as follows:
1. For use in the formation of a wall, a plurality of vertical precast wall units, each unit including opposed vertical edge portions, a groove defined along each edge portion, the grooves on a pair of adjacent edge portions on a pair of adjacent aligned units combining in opposed relation to each other to define an elongated keyway, and a plurality of keys engageable within and between the keyway forming grooves at spaced points there along in a manner so as to lock the unit edge portions of the adjacent units to each other and preclude relative movement therebetween, each groove being of a dovetail configuration, the keys being of a configuration conforming closely to the opposed grooves and being wedgedly receivable therein, the grooves being longitudinally tapered for a wedging reception of the keys therein upon a longitudinal movement of the keys along a formed keyway, each key including a flat plate having opposed groove receivable dovetail portions, and depending flanges secured to said late eri herall ther about.
2. lhe Eons ructioii of cfaim 1 wherein each unit includes opposed faces with the faces on a pair of adjacent units being in edge-to-edge contact laterally outward of the groove formed keyway therebetween.
3. The construction of claim. 2 wherein each edge portion, between the groove therein and the adjacent faces, is configured so as to, upon joining the adjacent edge portions of a pair of adjacent units, form a grout channel opening inwardly into the formed keyway and closed exteriorly by the contacting unit faces.
4. The construction of claim 3 wherein each key includes an enlarged opening defined centrally through the plate for the reception of reinforcing bar means and keyway filling grout.
5. For use in the formation of a wall, a plurality of vertical precast wall units, each unit including opposed vertical edge portions, a groove defined along each edge portion, the grooves on a pair of adjacent edge portions on a pair of adjacent aligned units combining in opposed relation to each other to define an elongated keyway, and a plurality of keys engageable within and between the keyway forming grooves at spaced points there along in a manner so as to lock the unit edge portions of the adjacent units to each other and preclude relative movement therebetween, each groove being of a dovetail configuration, the keys being of a configuration conforming closely to the opposed grooves and being wedgedly receivable therein, each key including a flat plate having opposed groove receivable dovetail portions, depending flanges secured to said plate peripherally thereabout, and an opening defined centrally through the plate for the reception of reinforcing bar means and keyway filling grout, two such keys being provided in each keyway.
6. For use in the formation of a structure, a plurality of sections, each section including opposed edge portions, a groove defined along each edge portion, the grooves on a pair of adjacent edge portions on a pair of adjacent aligned sections combining in opposed relation to each other to define an elongated keyway, and a plurality of keys engageable within and between the keyway forming grooves at spaced points there along in a manner to lock the section edge portions of the adjacent sections to each other and preclude relative movement therebetween, each groove being of a dovetail configuration, the keys being of a configuration conforming closely to the opposed grooves and wedgedly received therein, each key including a flat plate having opposed groove receivable dovetail portions, and laterally projecting flanges secured to said plate peripherally thereabout.
7. The construction of claim 6 wherein each section includes opposed faces with the faces on a pair of adjacent sections being in edge-to-edge contact laterally outward of the groove fonned keyway therebetween.
8. The construction of claim 6 wherein the grooves are longitudinally tapered for a wedging reception of the keys therein upon a longitudinal movement of the keys along a formed keyway.
WWW STATES PATEN'E @FFECE QERTEFEQATTE RRETKON Patent No. 55 3 Dated August 29, 1972 Inventm-( Richard Wo Adams It is certified that error appears in the above-identified patent and that said Letters Patentere hereby corrected as shown below:
Page 1, column 1, line 3; delete "IaxahatgheWan substitute --Lake worth Signed and sealed this 10th day of July 1975.
(SEAL) Attest: v
EDWARD M.FLETCHER,J R. Rene Tegtmeyer Attesting Officer Acting Commlssloner of' Patents ORM PO-l 050 (10-69) USCOMM-DC 60376'P69 A IJ.S. GOVERNMQNI' PRINTING OFFICE 1968 0-365-334.