Void creating devices and method for making concrete structures using such devices

Void creating devices and method for making concrete structures using such devices

התקנים מייגרי חללים ושיהה לקשיית פבני בטון תוך

שסו® בהתקנים אלה

Inventor: ROBERT K. STOUT

APPARATUS AND METHOD FOR MAKING CONCRETE STRUCTURES

ABSTRACT

A device to be embedded in a concrete structure in order to define a labyrinth of passageways within the concrete structure comprises a void creating device formed of frangible material and which is an elongated hollow member preferably made of two interfitting sections, with the hollow member having at least two opposed projections disposed intermediate the length of the hollow member. When embedded in concrete, the ends of the elongated hollow member and the ends of the opposed projections extend to the surface of the concrete such that such projecting frangible elements may be pushed out or removed in order to enable the passage of service lines through the interior of the concrete structure. The subject method for making a cast-in-place concrete structure comprises the steps of forming an arrangement of concrete forms; placing a plurality of said void creating devices within the confines of and spaced from the concrete forms, with the respective projections of adjacent devices abutting one another in order to enable internal communication between said :devices, and with the ends of the devices and the non-abutting projections thereof extending to the periphery of the concrete forms, and pouring uncured concrete into the spaces in and around and in intimate contact with the void creating devices, and allowing the concrete to cure. Subsequently, the frangible ends and exposed projections of the void creating devices may be knocked ׳out in order to provide access Into the labyrinth of passageways defined by the hollow devices within the interior of the composite concrete structure. The subject void creating devices and the subject method result in a one-process system for achieving a one-layer, composite, self-insulating concrete construction unit, which unit may be individually finished on both sides.

The present invention relates to a new and / useful device to be employed in the construction of concrete structures, and a new and useful process for making' a cast-in-place concrete structure. The latter is of a single layer, self-insulating, composite construction, and may be finished on both surfaces thereof, and it is specifically characterized by an internal labyrinth of passageways, extending in three mutually orthagonal directions in order to accommodate utility service lines and the like, as well as to accomplish a multitude of basic uses and functions, as more specifically set forth below.

The primary accomplishments of the void creating device of the subject invention are:

(1) The creation of a sophisticated labyrinth of passageways within the concrete structure, which passage ways may. be opened to the exterior of the concrete structure in any one of three mutually orthagonal axes;

(2) Significant improvement in the weightstrength ratio of the concrete structure and a significant reduction of the mass-weight ratio, especially in light of the fact that up to 66 2/3% less concrete is required to complete a concrete structure when using the subject void creating device, as contrasted to conventional concrete construction. Furthermore, the design of the subject void creating device is controlled to eliminate all excess concrete but at the same time allow within very critical tolerances, the correct amount of concrete for structural purposes. In addition the subject device may be configu^dX to facilitate the proper and exact positioning of reinforcing bars within the concrete form during the pouring of the uncured concrete;

(3) Extremely effective insulating properties of the resulting concrete structure which is inherently achieved by the embedding of the void creating device of the subject invention into the concrete structure;

(4) As embedded in a concrete beam structure, the void creating device of the subject invention provides for connection and interconnection of individual concrete beam units so that the latter may function as a single unit in a completed building or wall structure;

(5) The void creating device of the subject invention provides the capability for specific area reinforcing in the resulting concrete structure to meet the structural requirements of the structure, such as concentrated loads resistance to dynamic forces, specific area strength, etc.;

(6) The void creating device is a single, all purpose, interchangeable construction module which may be readily employed by unskilled labor in the construetion of concrete structures, and which, furthermore, does not require heavy construction equipment, thereby resulting in a great reduction of labor costs; and (7) The use of interconnected void creating devices in a concrete structure provide an inherent three-directional, built-in network of ducts for heating and air conditioning. '^ώ י'

In addition to the above, while embedded in the concrete structure, the void creating device inherently provides additional advantages to the resulting composite structure. More particularly, preferably the void creating device is made of an insulating material whereby additional insulative properties are imparted to the concrete structure, in addition to the insulative qualtities provided by the labyrinth of passageways which define the dead air space within the concrete structure. Furthermore, since the insulation material of the void creating device per se and the dead air space are at the center of the concrete structure, this arrangement provides a unique single layer, self-insulated concrete structure that may be completely finished on both surfaces. This type of concrete structure has long been a desired objective of the construction industry, and is now provided by means of the void creating device of the subject invention.

Another advantage inherently achieved by the subject void creating device is realized during the curing of the concrete structure. Since the void creating device is preferably made of a frangible, insulative, waterproof, inert, inorganic material, it tends to retain the heat given off by the concrete during curing thereby reducing the curing time of the concrete and increasing its strength.

Using the subject method, there is provided a low cost process of creating a cast-in-place concrete 1 construction that is of composite construction, self insulated, finished on both sides, and includes an internal labyrinth of passageways extending in three mutually orthagonal directions for accomodating utility service lines internally of the construction unit. In addition, the method of the subject invention results in. a concrete structure having an improved weight-strength ratio, while simultaneously achieving a reduction of unnecessary weight and mass of concrete, to the extent of reducing the mass of concrete by as much as 66 2/3%, as contrasted to a completely solid concrete structure. In addition, utilizing the subject method the resulting concrete structure inherently achieves effective insulation of the concrete structure to meet the requisite insulating requirements, increased fire rating, more efficient sound transmission properties, and accomplishes these results with reduced labor requirements, reduced material requirements, and reduced elapsed time for the construction of the concrete structure, all of which result in significant cost reductions in the making of the concrete structure.

These and other advantages and objectives are achieved by the process of the subject invention which basically comprises the steps of forming an arrangement of concrete forms to define the peripheral dimensions of the concrete structure, placing a plurality of hollow void creating devices within the confines of said concrete forms, each void creating device being an elongated hollow member made of frangible material having at least one pair of opposed projections intermediate its length, with the respective projections of adjacent devices abutting one another in order to enable communication between the devices, and with the frangible ends of the devices and the non-abutting projections thereof extending to the peripheral edges of said concrete forms;

and the further step of forming the concrete structure by pouring uncured concrete into the spaces between the concrete forms and the void creating devices, and allowing the concrete to cure. After the concrete has cured, the concrete forms may then be removed, and the exposed frangible ends and exposed frangible projections of the embedded.void creating devices may then be knocked out or removed thereby providing access to the labyrinth of passageways created within the composite concrete structure. In addition to providing access through the vertical and horizontal edges of the concrete structure, portions of the concrete structure in the facing walls thereof may be removed in the vicinity of other frangible projections of the void creating devices, thereby resulting in three-dimensional access from the exterior of the resulting concrete structure to the interior thereof. Service and utility lines may then be ducted through the concrete structure, and if desired, the passageways defined by the void creating devices may be employed as internal plenums

I for conducting heating and cooling fluid flows. ^v

The void creating device of the subject invention generally. comDrises an elongated hollow member made of a frangible, inert, waterproof, inorganic insulatί ing material, and preferably made of two interfitting half-sections, with the elongated hollow member having at least two opposed projections disposed intermediate the length thereof. A single hollow member may be embedded in a single concrete beam, or a plurality of such elongated hollow members may be interconnected and placed within conventional concrete forms for the construction of a cast-in-place concrete structure. The opposite ends of each elongated hollow member are exposed, as well as some of the ends of the opposed projections, thereby enabling access, by removing or punching out of the frangible projections, to the labyrinth of passageways defined by the devices within the interior of the resulting concrete structure. . Preferably, the void creating device is of generally rectangular cross section and includes two sets of opposed, spaced projections extending intermediate the length thereof, with the two sets of projections extending from the respective opposed sides of the rectangular cross section. By this arrangement, in conjunction with the ends of the hollow frangible member, three dimensional access is provided to the interior of the concrete structure.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded, perspective view of a void creating device of the subject invention;

FIG. 2 is a plan view of one of the two interfitting sections forming a portion of a void creating device of the subject invention;

FIG. 3 is a cross sectional view of the void creating device of the subject invention taken through an intermediate section where opposed projections are provided;

FIG. 4 is a detailed view of one embodiment of locking means for retaining two interfitting sections of the subject void creating device in a locked condition;

FIG. 5 is a plan view, partially in section, of an alternate embodiment of two interfitting void creating devices;

FIG. 6 is a perspective view, partially in section, of a void creating device as embedded in a single concrete beam structure; ־’

FIG. 7 is a perspective view, partially in section, depicting the several stages involved in the method of the subject invention for making a concrete structure;

FIG. 8 is a perspective view of apparatus employed in the subject process preparatory to the step of pouring the uncured concrete;

FIG. 9 is a sectional view of the apparatus _יtaken along line 9-9 in FIG. 8;

FIG. 10 is a horizontal sectional view through a portion of a concrete wall made according to the subject process wherein an internal reinforcing beam is provided;

FIG. 11 is a vertical sectional view of a concrete wall made according to the subject process and taken along line 11-11 in FIG. 7;

FIG. 12 is a vertical perspective view of a portion of a concrete wall made according to the subject process wherein access to the labyrinth of passageways within the concrete wall is effected through a portion of the concrete wall; and

FIG. 13 is an exploded, perspective view of an alternate embodiment of a concrete form employed in the subject process; and

FIG. 13A is a cross-sectional view of the concrete form of FIG. 13 showing two alternate embodiments of the form surface which contacts the concrete.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1, 2 and 3, the void creating device of the subject invention is designated by the numeral 10 and basically comprises an upper section 12 and a lower section 14, with the device 10 being of an integral, molded construction and made of a frangible material such as polystyrene foam. Alternatively, any other suitable plastic foam that is rigid and substantially non-compressible may also be employed fcr the manufacture of device 10, and other suitable plastic foams include epoxy foams, phenolic foams, polyurethane foams of the rigid or closed cell type, closed cell polyvinyl chloride foams, and cellulose acetate foams.

The configuration of the void creating device 10 is generally elongated, hollow member of generally rectangular cross section, which is closed at its opposed ends by means of baffles 16, 16. The end baffles 16, 16 are of tongue and groove configuration whereby two devices 10 may be interconnected and interfitted along their axial length when the devices are to be embedded in a concrete structure of greater length than each device 10. The end baffles 16, 16 may have lines 18 of reduced thickness in order to facilitate the removing ־or knocking out of the end baffles when it is desired to gain access to the interior of the resulting concrete structure for the passage of service lines or the like, as more fully described hereinafter.

Disposed intermediate the length of the device 10 is at least one pair of opposed projections 20, 22 that are hollow and include closure baffles 24 and 26, respectively, that may likewise be knocked out or removed in order to enable passage of service lines into the interior of the void creating device 10. As clearly illustrated in FIGS and 3, the opposed projections 20 and 22 are preferably of a truncated, conical configuration, with the greater diameter being at the extremity of each projection adjacent the respective closure baffle 24,26, and as also more particularly illustrated in FIG. 3, the opposed projections 20 and 22 are configured in a tongue and groove configuration in order to enable the interconnection and interfitting of adjacent void creating devices, as more fully explained hereinafter with reference with FIGS . 7, 8 and 11.

As shown in FIG. 1, the void creating device may be provided with a plurality of the spaced,opposed projections 20 and 22 extending from opposite sides 28 and 30 of the void creating device, and in addition a second set of opposed projections 32 and 34 may be provided on the other opposed sides 36 and 38 of the void creating device 10. Projections 32 and 34 may be of any suitable configuration, and are illustrated as being generally rectangular in configuration, as will be' more fully described hereinafter, are usually positioned so as to face the opposed surface walls of the resulting concrete structure.

In order to maintain, during the construction of the resulting concrete structure, the void creating device at the desired location within.the concrete form, the void creating device 10 may be provided with a plurality of spacer elements 40 that are integrally formed with the opposed projections 32 and 34. As illustrated in FIG. 3, preferably each spacer element 40 is of a generally truncated conical configuration, having a relative ly small flat end portion 42 which normally abuts against: the concrete form for maintaining the device 10 in proper position during the forming of the resulting concrete structure, (see FIG. 9).

Extending along portions of the length of the upper section 12, and internally thereof are elongated flanges 44 which cooperate with similarly configured longitudinally extending cut-outs 46 (see FIG. 3) provided in the lower section 14 in order to maintain the upper section 12 and lower sections 14 in interfitting relationship. Similar flange and cut-out arrangements may also be provided along the end baffles 16, 16 for additional support.

Disposed internally of the void creating device 10 are internal baffles 48 which extend transverse to the longitudinal axis of the device 10, and which function to compartmentalize the interior of the void creating device 10. Each baffle 48 may also include reduced thickness lines 50 which define lines.of weakness in order to facilitate the knocking out of the internal baffles 48 when it is desired to duct service lines or the like therethrough. As shown, the.internal baffles 48 are defined by cooperating half-sections formed integral with upper section 12 and the lower section 14.

In order to maintain the upper and lower sections 12, 14 in a locked relationship, a suitable locking means, preferably of the mechanical type and formed integral with said sections 12 and 14, may be provided. As an example, reference is made to FIG. 4 wherein formed integral w1־th the upper section 12 is a protrusion or hook shaped extension 52 which is adapted to be inserted and force fit into a cooperating hole 54 in the lower section 14 in order to lock the lower and upper sections together. Such locking mechanism may be provided at the four corners of the upper and lower sections, and possibly intermediate the length thereof where required. Alternatively the half-sections may be bonded together.

Referring again to FIG. 3 the corners of the cross section of the void creating device 10 are preferably beveled, as designated by numeral 56. The beveling of the corners facilitates the positioning of reinforcing bars 80 extending parallel to the longitudinal axis of the void creating device and disposed at positions adjacent to the corners 56. This is more particularly shown in FIGS. 6 and 7.

FIG. 5 illustrates an alternate embodiment of the void creating device, and is partly in section in order to clearly indicate the interfitting of two void creating devices preparatory to being embedded in a concrete wall structure. As illustrated in FIG. 5, the opposed projections 20, 22 of the adjacent devices are interfitted by virtue of their tongue and groove configuration in order to establish an interlocking relationship between the adjacent void creating devices 10. In addition, as a modification of each device, each device is provided with elongated strips 58 which project laterally from the sides 28 and 30 intermediate the spaced projections 20 and 22. When two void creating devices are interfitting as shown in FIG. 5, the elongated strips 58, being an integral part of the respective void creating device 10, are in the abutting relationship thereby defining a complete insulation barrier which is to be embedded in a concrete wall. The elongated strips 58 are preferably flat, and may extend from both the upper and lower sections 12, 14, or alternatively, the strips 58 may be provided only on one of the sections of the void creating device. The thickness of strips will generally conform to the thickness of the walls of the void creating device 10, and as previously mentioned, would be integrally molded with the device so as to form a single unitary structure. In the lower right hand corner of FIG. 5 there is illustrated the interconnection of two devices 10 by the interfitting of their tongue and groove end portions adjacent baffles 16, 16.

FIG. 6 illustrates ^,the use of a void creating device 10 of the subject invention as embodied in a concrete beam in order to provide three dimensional access to the internal hollow structure of the beam. More particularly, as shown in FIG. 6, the concrete beam 160 comprises a composite structure of the internal void creating device 10 which is surrounded by and in intimate contact with a continuous circumferential concrete structure 162. That is, except for the end baffles 16, and the exposed baffles 24, 26 of the opposed spaced projectig^ 20, 22. In addition, because of the fact that the opposed projections 32 and 34 extend beyond the opposed surfaces 36 and 38, the thickness of the concrete 62 in the region of said projections 32 and 34 is less than around other portions of the void creating device. Accordingly, access to the hollow interior of beam 160 may be readily accomplished through the top of the beam (as shown in FIG. 6) by cutting a hole 164 in the concrete structure 162 in the region of the projection 32 to thereby provide access through the upper portion of the beam to the interior of the void creating device 10. Since the opposed projections 20 and 22 extend to the outer surface of the concrete 162, access to the interior of the void creating device through the opposed projections 20 and 22 is simply a matter of removing or knocking out the baffles 24 and 26 within the projections 20 and 22, respectively. Likewise, access through the ends of the beams is readily accomplished since end baffles 16 of the void creating device 10 are exposed.

By this arrangement, it is apparent that three dimensional access to the interior of the void creating device (and hence the beam 16$) is readily achieved. Thus the labyrinth of passageways within each beam 160 is readily accessible for passage of service lines and the like of the resulting building structure in which the beam 160 is embodied. As illustrated in FIG. 6, preferably reinforcing bars 80 are disposed adjacent each of the beveled corners 56 of the void creating device, and in addition circumferential reinforcing bars ,168 may be provided.

In the process of the subject invention, the first step is to form an arrangement of concrete forms to define the periphery of the concrete structure. Referring to FIGS. 7 and 8, two-spaced concrete forms may be provided by the interconnection of the plurality of concrete forms 70 that are interconnected by means of bolts 72 and/or bolt and wedge means 74, with the concrete forms being retained in spaced relationship by means of wall ties 76. The latter may be constructed to include apertures 78 through which reinforcing bars 80 may extend for maintaining the latter in position prior to the pouring of uncured concrete, as more fully described hereinafter.

In order to achieve a completed concrete structure 60 that is finished on both exterior wall surfaces, preferably the concrete forms 70 are of the type which include a finished pattern, illustrated as a brick pattern in FIGS. 7 and 8, whereby the resulting concrete structure merely requires decorative painting. Other patterns may also be provided on the concrete forms such as adobe .patterns, smooth surface, and intaglio patterns.

For the making of a horizontal wall structure, such as the foundation or intermediate floors of a building structure, a plurality of concrete forms 71 may be inter15 connected to define the base of the form structure, the sides of the resulting concrete structure may be defined by upstanding concrete forms, designated 71a in FIG. 7. The combination of the forms 71 and 71a define the penphery of the generally horizontal concrete structure 60.

After the concrete forms are in place, the next step in the subject process is to place a plurality of void creating devices 10 within the confines of the concrete forms, and spaced from the interior wall surfaces thereof. As illustrated in FIG. 9, the spaced elements 40 of the void creating device 10 abut the interior surfaces of the concrete forms 70, thereby maintaining the void creating device in an exact and precise position in order to insure the uniform distribution. of the uncured concrete about and in intimate contact with the external surfaces of the void creating devices. The plurality of void creating devices are interconnected by means of the respective tongue and groove projections 20 and 22, as shown in FIGS. 7 and 8. The baffle ends 16 of the devices extend to the periphery of the concrete form, and the non-abutting projections 20, 22 also extend to the periphery of the concrete form. In other words, the end projections 20, 22 are in contact with the periphery of the concrete form, the end baffles 16 are exposed or in contact with the concrete form, and the ends 42 of the spacer elements 40 are in contact with the concrete forms 70. The dimensions of the void creating devices, as the spacing of the concrete forms, is suitably designed so as to insure sufficient concrete around and intimate contact with each void creating device so as to meet the structural requirements of the resulting concrete structure 60.

As shown in FIGS. 7 and 9, suitable reinforcing steel in the form of reinforcing bars 80 may be provided to extend in generally orthagonal directions within the concrete forms 70. The vertical extending reinforcing bars 80 are preferably positioned and spaced from the bevelled corners 56 of the void creating devices 10 to ensure proper concrete coverage, while the horizontal reinforcing bars may be supported by passage through the apertures 78 in the wall ties 76. Alter natively the bars 80 may bear against projecting.portions of the devices 10, and in'so doing aid in the positioning of the devices 10 within the forms 70.

The next step in the subject process is the forming of the concrete structure by pouring uncured concrete into the spaces defined between the concrete forms 70 and the void creating deviqes 10 so as to embed the void creating devices 10 within the concrete except for the end baffles 16, and the non-abutting projections 20, 22. As the uncured concrete is poured into the spaces between the concrete form 70 and the void creating devices, it flows in and around the extending projections •20,. 22 and is in intimate contact with the i void creating devices 10, thereby resulting in a unitary, ; continuous concrete structure that has embedded therein the void creating devices 10. The composite arrangement of the concrete and the void creating devices provide^, the new and unusual construction of a composite concrete structure, with the insulation properties being provided by the combination of the void creating devices (which are preferably made of an insulating material such as polystyrene), and the dead air space which is embedded within the resulting concrete structure 16 by virtue*of the hollow* interiors- of the* id-creating— devices. Those hollow interiors also define the labyrinth of passageways which enable the ducting of utility service lines and the like through the concrete structure, as described below.

The uncured concrete is allowed to cure to a sufficient degree, after which the concrete forms 70 are removed, and since such forms are provided with a patterned form surface, such as brick, the resulting concrete structure is both structurally and aesthetically complete.

Referring particularly to FIG. 7., numeral 100 designates an electrical cable that may be extended through the hollow interior of a void creating device in order to provide electricity to an outlet, indicated by numeral 102. After the concrete structure 60 has cured, the end baffle 16 of the void creating device 10 is knocked out or removed, as well as the internal baffles 48 in order to enable the cable 100 to be passed downwardly through the concrete structure 60. To provide access to the hollow interior of the void creating device in order tgft* connect the cable 100 to the outlet 102, it is merely necessary for the mechanic to remove that portion of the concrete wall 62 in the vicinity of the projection 32 extending from the void creating device 10. Reference is made to FIG.12 which illustrates the opening through the concrete structure 60 created by the mechanic so as to provide access through the face of the concrete wall 62 to the interior of the void creating device. Cable 100 is then pulled through the opening, after which the outlet 102 is connected to the cable ;.and the outlet is then suitably affixed to the wall of the concrete structure 60. By this arrangement, there is achieved the ducting of electrical service lines internally of the concrete structure.

An electric cable, or for that matter any other utility service line, may also extend transverse to the longitudinal axes of the void creating devices as embedded in the concrete structure. Referring to FIG. 7, electrical cable 104 is ducted through a plurality of void creating devices by the mechanic merely knocking out the exposed end baffle 26, and thereafter removing the baffles of the projections 20, 22 of abutting void creating devices in order to extend through the floor of the concrete structure, such as a house. The cable 106 is then ducted upwardly through the floor and through the hollow interior of a vertically disposed void creating device to reach

I outlet 106 that is provided in the wall structure in the same manner as outlet 102. From outlet 106, additional wiring 105 may extend vertically upwardly through the same void creating device.

In like manner, other utility service lines such as water pipes 110 may be ducted transversely and longitudinally within the concrete structure, as illustrated in FIG. 7. In addition, the water pipes may extend through the wall 62 by the removal of the thinner portions of the concrete in the vicinity of projections 32 and 34. This is illustrated in FIG.7 wherein the plumbing pipes 112 for servicing the sink 114 extend through the wall 62 of the concrete structure 60 in order to connect to the vertically extending pipes 110. The provision of the opposed projections 32 and 34 which are positioned so as to face the opposed walls 62 and 64 of the concrete structure, insures that the concrete coverage is less in the vicinity of said opposed projections 32, 34, but is still sufficient for structural purposes. The walls 62 and 64 may readily be broken through in order to achieve the desired three-dimensional access to the labyringth of passageways defined by the void creating devices 10 as embedded in the concrete structure 60. As also illustrated the sanitary service line 120 for the toilet 122 may likewise be ducted through the labyrinth of conduits defined by the void creating devices within the concrete structure.

Since the void creating devices 10 are made oi

20.

a frangible, insulating, waterproof, inorganic, and inert material, selected baffles 16, 20, 22 and internal baffles 48 may be removed in order to create ducting which defines a plenum conduit whereby heating or cooling air may be passed, for ultimate distribution to the house structure through registers, such as indicated at 130 in FIG.7.

Accordingly, as is readily apparent from FIG. 7 , three dimensional access to the interior of the resulting composite concrete structure is readily achieved by merely knocking out selected portions of the void creating devices. More particularly, with respect to the upstanding wall illustrated in FIG. 7 , vertical access is achieved by knocking out end baffles 16 of the devices 10; transverse access is achieved by knocking out the respective baffles of projections 20 and 22; and in the third mutually orthagonal direction by cutting into the face of a wall 62, 64 of the concrete structure, and then through a respective projection 32, 34 to the interior of the void creating device. Because of the interfitting of .the abutting projections 20 and 22 of the adjacent devices 10, a complete three-dimensional labyrinth of passageways within the resulting concrete structure 60 is provided.

FIG. 11 is a cross sectional view through the completed concrete structure 60 to illustrate the internal labyrinth of passageways. As noted above, it is merely necessary to knock out the interfitting tongue and groove baffles of the projections 20 and 22, and the internal baffles 48 in order to create passageways within thg^onCrete structure 60.

For certain applications where the concrete structure is to be locally reinforced, such as by means of a vertical post or a horizontal beam, a vertical or transverse passageway within the structure may be created by knocking out the respective frangible, portions of the void creating devices, and the passageway then subsequently filled with uncured concrete that is allowed to cure. As illustrated in FIG.10, in order to create a horizontal beam, such as header for a doorway, or over a window opening, the respective tongue and groove projections 20, 22 may be knocked out and concrete then forced through the horizontal passageway, and allowed to cure. The internal baffles 48 function to limit the concrete to the desired area of the respective devices 10. In like manner, in order to form a vertical post, as for example in the j

I I void creating device (designated 140) of the vertical wall illustrated in FIG. 7., it is merely necessary to knock out baffle 16 and internal baffles 48 within said device, and subsequently filling said device with concrete 142, and allowing the concrete to cure. Such may be desirable in a case where the vertical wall is to support a second floor or next higher floor of the building.

FIGS. 13 and 13A illustrate an alternate embodiment of the concrete forms that may be employed in the subject invention. Forms 70, as shown in FIG. 7, are of a one piece metallic construction, whereas the alternate embodiment designated by numeral 170 in FIGS. 13 and 13A, comprises a metallic frame 172 which cooperatively receives a molded face member 174 preferably made of a. lightweight plastic material. More particularly, frame 172 provides the necessary strength for retaining the uncured concrete during the molding operation, and is made of a lightweight metallic material such as aluminum, and includes slot indentations 173 for the interconnection of abutting forms 170. Furthermore, the frame 172 is configured to include a plurality of apertures 175, and an internal lip 176 which cooperates with the flange portion 177 of the molded face member 174 for interconnecting of said members. Bolts 178 are provided for fixedly connecting the molded face member.174 to the frame 172. On the back portion of the molded face member 174 there are provided a plurality of reinforcing ribs 180, while on the opposite face of the member 174, i.e., the portion which contacts the uncured concrete, the face member is configured to the desired configuration of the resulting concrete structure. As shown on the left-hand portion of FIG. 13A, the forming face of the member 174may be configured in a brick pattern including mortar joint extensions 182 and intermediate brick face patterns 184. On the right-hand portion of FIG. 13A there is illustrated the configuration of the molded face member 174 for a smooth concrete form, as designated at 186.

The alternate embodiment of the concrete form 170 as illustrated in FIGS. 13 and 13A provides the necessary desirable characteristics of not deflecting under the application of the hydrostatic load of the uncured concrete; providing a form which may be used repeatedly thereby effecting economy; a form which will not deteriorate or deflect; and provides the feature of inherently achieving the desired exterior surface pattern of the resulting concrete structure. Furthermore, from a structural standpoint, the combination of the strong metallic frame 172, and the molded plastic face member 174 provides a composite form which is capable of withstanding' repeated stress and hard handling usage by contractors, as contrasted to an all plastic form. Furthermore, the combination of elements making up form 170 provides a very lightweight form that may be readily transported and the replaceability of the molded face members 174 insures, that a great variety of different concrete patterns may be employed by merely replacing the molded face member 174 in the frame 172.

It is also noted that the combination of the metallic frame 172 and the plastic face member 174 reduces the overall cost of the form 170 in light of the fact that plastic is relatively inexpensive as compared to metal.

In summary, the subject invention provides an apparatus and a process for constructing a concrete structure using void creating devices, which concrete structure is self-insulating, of single layer construction, and may be finished on both surfaces, and is charate^iwed by an internal void system that extends in three mutually orthagonal directions so as to enable the internal ducting of utility service lines therein, and which additionally provides the advantages of increased strengthweight ratio, with significant decreases in the amount and weight of concrete required. The void creating devices remain an integral part of the concrete structure and are made of an insulative material that renders the construction unit self-insulating. Furthermore, the thickness of the devices may be varied to meet any thermal requirement, and the hollow device inherently creates dead air space in the finished construction unit.which in itself is an important insulator.

The subject process is economical, especially from the standpoints of time, material, and labor, and results in a superior concrete structure that may be employed in any form of building, including houses, commercial buildings, industrial buildings, and the like. The process of the subject invention results in a construetion unit that has been the age old dream of the construetion industry, and is now provided by means uf the subject invention.