A lost form for concrete which comprises insulting slabs of foam material reinforced by a core and held in place in an upright orientation by horizontal base elements, horizontal connecting elements disposed between the tiers of slabs and vertical elements bridging pairs of slabs of each tier. The horizontal elements have a ladder-like configuration with longitudinal members engaging in formations in the lower and upper edges of the slabs and transverse members extending horizontally between and spacing apart the slabs. The vertical elements also have a ladder-like configuration with vertical longitudinal members received in confronting grooves of the slabs and vertically spaced horizontal transverse members which bridge the slabs. The elements are retained in the cast concrete wall and hold the slabs thereagainst.

FIELD OF THE INVENTION 
Our present invention relates to a construction system utilizing so-called 
lost forms, i.e. a formwork for the casting of concrete made up of walls 
or panels which are left in place once the concrete hardens. In particular 
the invention deals with lost-form falsework and reinforcing structures, 
to concrete forms constituted by such falsework and the walls or other 
structures obtained from the casting of concrete therein. 
BACKGROUND OF THE INVENTION 
Structures such as buildings, public works and the like are frequently 
produced from concrete by casting the concrete into a space defined 
between two walls or surfaces and permitting the concrete to harden 
therein. The form is constituted by so-called falsework, i.e. a structure 
which does not itself constitute the final load-bearing member of the 
structure and such forms or falsework can be of two types, namely, 
removable forms which may or may not be reused or so-called lost forms 
which remain in place in the structure after the concrete has hardened. 
Lost forms can include insulating members which by their presence on and in 
the hardened concrete structure, contribute thermal or insulating 
properties to the structure which may be a wall. Of course, the lost forms 
can contribute other properties, e.g. weatherproofing, esthetic 
characteristics or the like. 
When the lost forms are to provide insulating characteristics, the material 
from which the forms are constituted can be composed of insulation or 
insulating material. 
The lost forms which have been provided heretofore generally can also be 
divided into two categories, namely those constituted by planar solid 
slabs and those formed by hollow parallelopipedal blocks. 
The large planar slab units have not gained widespread acceptance because 
their dimensions are determinitive of the dimensions of the structure to 
be cast and frequently it is not possible to employ these slabs 
conveniently in building or other structures. Furthermore, the use of such 
slabs is complicated by the need to employ connectors between the slabs 
which are difficult to emplace. Furthermore, they generally do not have 
sufficient insulating capabilities especially at the extremities of a wall 
to be formed by casting concrete into the lost mold. 
The second type of lost form, namely that which is composed of hollow 
parallelopipedal blocks can be utilized for a greater range of structures 
because they are emplaced simply by disposing one block next to another 
and stacking rows of blocks in an imbricating pattern. Such arrangements 
can be adapted to various architectural plans and designs. Nevertheless 
they too pose considerable problems. 
For example, once the wall is formed, the connections between the blocks 
are formed by insulating material tending to melt or to be thermally 
destroyed in the case of fire, leaving openings in the concrete wall. 
These horizontal "conduits" can be of considerable diameter and create the 
danger of airflow and thus of transmission of fire. 
The angles at which the blocks join are comparatively weak and weaknesses 
occur as well at the junctions between rows of blocks, i.e. because the 
horizontal joints between the concrete constitute one wall and the 
concrete constituting an adjacent wall constitute discontinuities. 
The volumes of the blocks, moreover, create problems with respect to their 
transport and transport costs because the ratio of volume-weight is 
considerable. As a consequence, even such lost forms have not gained 
widespread acceptance. 
OBJECTS OF THE INVENTION 
It is the principal object of the present invention to provide an improved 
lost-form construction system whereby advantages of both types of lost 
forms can be obtained without their respective disadvantages and which 
will obviate drawbacks of earlier systems. 
Another object of this invention is to provide lost-form concrete molds for 
building and other structures which can be assembled quickly, which can be 
utilized to produce strong concrete structures, and which affords 
excellent insulating capabilities to the completed concrete wall 
structure. 
SUMMARY OF THE INVENTION 
These objects and others which will become apparent hereinafter are 
obtained in accordance with the present invention by providing insulating 
slabs which are interconnected by horizontal ladder-like connecting 
elements engaging the slabs and upon which the slabs are positioned to lie 
in vertical planes through the respective longitudinal members of these 
elements which are bridged by horizontally spaced transverse members 
thereof. These horizontal ladder-like elements are used to engage the slab 
edges adapted to rest upon the ground or foundation structure and to 
support the bottom edges of successively higher tiers of such slabs and in 
the latter case are fitted into grooves of the upper edges of underlying 
slabs. In addition, the slabs are bridged by vertical ladder-like 
connecting elements of a height greater than the height of the slabs so 
that each of these vertical ladder-like connecting elements extends across 
at least two and preferably a multiplicity of tiers of such slabs. In this 
case, the longitudinal members of the vertcal ladder-like elements are 
received in vertical grooves along the inner faces of the slabs of each 
tier and are bridged by transverse (horizontal) members which are 
vertically spaced apart. The vertical connecting elements and the 
transverse members of the horizontal connecting members can thus serve as 
reinforcements which are embedded in the concrete and reinforce the 
concrete wall while permanently retaining the insulating slabs 
thereagainst. 
According to a feature of the invention, each of the slabs is constituted 
by cellular synthetic resin or plastic material and comprises a core which 
constitutes an internal reinforcement, the core being affixed to 
reinforcing tubes which can be spaced apart in mutually parallel 
relationship along the core and with the slab. Preferably these tubes 
extend vertically and open at the opposite horizontal edges of the slab to 
receive pins projecting from the ladder-like horizontal connecting element 
which joins this slab to the opposite slab of the respective tier. 
Aligned slabs of a given tier can also be connected by plates having holes 
and disposed along these edges but transfixed by such pins as they pass 
from a horizontal connecting element into a respective overlying and/or 
underlying slab, and corners can be formed between slabs of a respective 
tier through the use of angles having such holes and lying along the upper 
and/or lower edge of the slab and likewise transfixed by such pins. Thus 
slabs of a given tier can adjoin orthogonally. Alternatively the angles 
can have pins engageable in the tubes. 
The inwardly facing surfaces of the slabs can be provided with uniformly 
spaced vertical grooves with such grooves of the two confronting slabs of 
a given tier being aligned with one another so as to receive the 
longitudinal members of a respective vertical ladder-like connecting 
element. 
Each horizontal ladder-like connecting element and each vertical connecting 
element can be interconnected at a common junction by an assembly formed 
from two mutually orthogonal elements including a horizontal element 
located above a vertical element, the two elements comprising means for 
locking them in their mutually orthogonal positions and being nestable 
such that the vertical element can lie within the horizontal element for 
transport and storage. These connecting elements can have the 
configuration of frames. 
The ladder-like structures forming the vertical and/or horizontal 
connecting members described above may be assembled, in turn from frames 
and any girder-like cross section may be utilized in forming these 
members. The upper edges of the slabs with which these connecting elements 
are used may be provided with forms at a spacing corresponding to the 
dimensions of the frame structures to allow interfitting of projecting 
portions of the slabs and the ladder-like connecting elements.

SPECIFIC DESCRIPTION 
The form slabs 1 are constituted by an insulating material having a 
strength sufficient to withstand the hydrostatic pressure of the concrete 
to be cast between the slabs. The slabs preferably are formed with a high 
density foamed synthetic resin such as expanded polystyrene, extruded 
polystyrene foam, polyurethane foam or a foamed phenolformadehyde or like 
resin. 
Within the body of each slab, we can provide a reinforcing mesh, forming a 
reinforcing core and which can represent any conventional reinforcing or 
strengthening material. For example, it may be constituted by or include a 
layer or body of the same insulating material which is not foamed or 
expanded, i.e. a core of the insulating material but of its molecular 
density. The core may also be constituted by perforated or imperforated 
foil such as a reinforcing plate, or a perforated member of pressed wood. 
The core may also be flexible or yieldable, e.g. in the form of glass 
fibers or a fabric thereof, a grid of wires, rods or filaments which can 
be fused, interwoven or tied at the crossovers, a synthetic resin fabric 
or metallic or nonmetallic filaments. 
The reinforcing core 2 is bonded to an array of mutually parallel tubes 3 
which are embedded in the slab 1 and open along the upper and lower edge 
faces of the slab when the slab is positioned vertically as shown in FIG. 
1. 
These tubes can be composed of practically any material, e.g. metal, 
synthetic resin or plastic, glass fibers embedded in an epoxy resin or 
even cardboard or paper as long as they have a sufficient rigidity to 
enable them to receive the pins of connecting elements in a manner to be 
described below. 
The connecting elements which space the slabs apart in a given tier and can 
serve to connect each slab to the slabs of the next tier can be the 
horizontal ladder-like elements 4 best seen in FIGS. 1 and 4. Each of 
these horizontal elements comprises a pair of longitudinal members 5 
interconnected by transverse members 6 which later may ultimately be 
embedded in the concrete cast between the slabs. The longitudinal members 
5 are provided with pins 7 adapted to engage in the tubes 3 of the slabs 1 
above and below the connecting element 4. In the embodiment shown, the 
pins only extend upwardly although it should be noted that similar pins 
can be provided to project downwardly to engage in an underlying slab of a 
lower tier. These elements 4 determine the spacing of the slabs of the 
tiers from one another. 
The elements 4 forming the base for the lowest tier can be positioned upon 
and fixed to the ground or a foundation member or floor while the elements 
4 disposed between the tiers are each disposed on the upper edge of a row 
of slabs of the preceding or lower tier so that the upstanding pins can 
engage in the tubes 3 of the overlying tier. 
Each slab 1 is formed along its inner surface (FIG. 3) with a multiplicity 
of parallel vertical grooves which are uniformly spaced along the length 
of the slab, i.e. are spaced apart in the longitudinal determination 
thereof. These grooves can receive either terminal plates 9 which can 
close a trough defined by the slabs 1 to constitute the mold or form for 
each tier, or vertical ladder-like connecting elements 10. 
The vertical connecting elements 10 are each constituted with longitudinal 
members 11 which can have thicknesses or widths equal to the widths of the 
grooves 8 to fit snugly therein and transverse members 12 which 
interconnect the longitudinal elements. 
Each of the transverse members 12 is provided with notches 12a along its 
upper surface to receive reinforcing bars 12b shown diagrammatically in 
FIG. 7 and adapted to be imbedded in the concrete which is cast in the 
trough once it is formed. The notches 12a are located at a fixed distance 
from each of the slabs 1 as will be apparent in FIG. 1. From FIG. 2 it 
will be apparent further that the horizontal members can also be notched 
to allow the positioning of vertical reinforcing bars in the assembly if 
desired, and that the same elements 10 which are utilized as vertical 
connecting elements can be utilized as horizontal connecting elements. The 
members 11 can be formed with pins 11a in regular spacing corresponding to 
a spacing of the bores 14 of angles 13 to facilitate connection of the 
slabs in the manner to be described. 
The vertical elements 10, as can be seen from FIG. 1, can have a length 
greater than the height of a slab and preferably greater than the height 
of a plurality of slabs so that a plurality of bars of slabs can be 
interconnected by them. 
As noted, another accessory which is utilized in the system of the 
invention is the angle 13. The angles 13 can be utilized to connect 
angularly adjoining slabs of a given tier by laying each angle in the 
adjoining recesses 1a and 1b of the upper and lower edges of the slab so 
that at least one hole 14 of each leg of the angle registers with at least 
one tube of each of the two angularly adjoining slabs. Then when a pin 7 
from a connecting element 4 or similar pins on a connecting element 10 or 
pins which can be separately provided are inserted through the holes 14 
into the tubes 3, the assemblies of slabs and angles are rigidly fixed in 
a static sense. 
Of course, as indicated in FIG. 7A, the angles 13a may be used, these 
angles being provided with pins 7a extending upwardly and downwardly for 
engagement in the tubes 3 of overlying and underlying slabs, respectivly. 
In this case, holes of members 11 (instead of pins thereof) can also be 
placed over or under the angles 13a for greater rigidity when the members 
10 are utilized as horizontal connecting elements. 
Thus, to assemble the form utilizing these elements of the invention, the 
connecting element 2 is affixed to an appropriate base and the slabs 1 are 
fitted over this element by aligning the respective tubes with the pins 7 
and placing the slabs over the longitudinal members 5 so that with these 
longitudinal members are snugly received in the groups 1b on the underside 
of each upright slab. The ends of the mold are closed by members 9 and the 
corners are formed utilizing the angles 13 or 13a in the manner described. 
Another row of horizontal connecting elements 4 or 10 is then applied along 
the upper edges of the slabs 1 of the first tier and in the groove 1a 
thereof. In addition, the vertical connecting elements 10 are inserted 
into the grooves 8 of the juxtaposed slabs at appropriate horizontally 
spaced locations and a second row of slabs can be applied, preferably in 
an imbrecating pattern with respect to the first row. Casting of concrete 
can be commenced after emplacement of the reinforcing rods 12b and the 
successive tiers can be applied as concrete casting continuance. This 
limits the hydrostatic force which must be sustained by the lowermost 
elements. When the concrete is set, the elements 4 and 10 remain in place 
within the concrete as additional reinforcement and firmly retain via the 
pins 7 and 7a and the engagement of the elements in the respective grooves 
of the slabs, the slabs along the faces of the concrete structure to 
provide insulating surfaces thereof. 
While embodiment of FIGS. 1-8 and 7A provides comparatively long 
ladder-like elements which can be utilized interchangeably and which are 
uniform in construction along their lengths, the ladder-like elements 
which are utilized in the embodiments of FIGS. 8-21 utilize different 
constructions for the element 15 (FIG. 10) adapted to space apart the 
slabs at the base and the element 16 (FIGS. 8 and 9) serving as elements 
of rigidification and as spacing elements above the base. 
The spacers 15 of the base are each constituted in the form of a frame 
having two longitudinal members 17 and two transverse members 18. The 
members 17 are of angle cross section so that they have horizontal flanges 
17a which can be fixed to the slab or foundation member provided on the 
ground. Their vertical flanges 17b are dimensioned to penetrate into 
longitudinal grooves formed in the lower edge surface of each slab (see 
FIG. 13). 
The transverse members 18 of each base element 15 each have two zones of a 
hook shape set off upwardly and close to the ends of these members.. 
Each transverse member 18, moreover, has a projecting edge portion along 
its upper edge, two such projections being provided such that each 
projection flanks a notch 18b in which a metal reinforcing bar or the like 
can be received. The notches are asymmetrical and are defined laterally by 
a boundry which is substantially on the side of the notch proximal to a 
respective slab and by a flank which is inclined on the other side 
enabling the positioning of the reinforcement, regardless of its diameter 
at a constant distance from the proximal slab. 
When each of the frame structures 15 is provided along the base of the 
slabs they collectively form a ladder-like array which functions in the 
manner described for the connecting element 4 previously. 
The other connecting elements 16 of this embodiment of the invention 
comprise two frame members represented generally at 20 and 21, each of 
which can be formed by a pair of longitudinal members and a pair of 
transverse members. 
The frame element 20, for example, is provided with longitudinal members 22 
and transverse members 23. The frame elements 21 have longitudinal members 
24 and transverse members 25. The two frame elements 20 and 21 can be 
articulated to one another at a junction between the transverse members 23 
of one frame element and 25 of the other. 
Each transverse member 23 has a salient portion 23a in which a notch 23b is 
provided with a configuration similar to the notch 18b to receive 
reinforcing bars. 
While the articulation can be constituted in a convenient manner, it should 
be noted that it is intended to permit the smaller element 21 to be 
received in the larger element 20 for storage, transportation or handling 
(FIG. 8) but to allow the frame elements that lie at right angles to one 
another as shown in FIG. 9 so that the frame elements 20 can form part of 
a horizontal ladder array while the frame elements 21 form part of a 
vertical ladder array (see FIG. 13) upon assembly. 
To this end, hook formations 30 which are complementary to and are 
engageable by the hook formations 31 (similar to the hook formations 19) 
can be provided. 
In the position of use the transverse member 25 while hooking into 
engagement with one of the transverse members 18, 23 is also positioned so 
that it locks the reinforcing bars 23c in the notches 18b, 23b in place. 
The longitudinal members 22 of element 20 which is utilized in a horizontal 
position, have a T cross section as shown in FIG. 11 so that the 
horizontal flange 22a can lie in a recessed zone 26 of a lower edge 
surface of a slab 1 while the vertical flanges 22b and 22c project into 
grooves 27 formed in upper and lower edge faces of the slabs 1 to be 
joined by this element in respective tiers. For best interfitting 
connection of the adjoining edge faces of the tiers of slabs, the upper 
edge surfaces have plugs 28 which fit snugly into complementary recesses 
29 formed in the lower edge surfaces. In the embodiment illustrated, these 
plugs and recesses are of square configuration and are regularly spaced 
along the slabs. 
Each element 21 has a width which is smaller than that of the element 20 to 
enable it to be received in the space flanked by the slabs 1. The 
longitudinal members 24 can have an L cross section (FIG. 12) or a channel 
cross section while the transverse members 25 at the extremities of the 
element 21 have the zones 30 which are in the form of hooks or clips 
enabling them to cooperate with the hooks 19 of the traverse 18 of the 
base spacer 15 and to abut the horizontal reinforcing bars. 
The transverse members 23 of element 20 also have two hook-shaped zones 31 
identical to the regions 19 of the base elements 15. As a result, each 
element 21 can cooperate both with the base element 15 therebelow and with 
an assembly 16 thereabove in similar fashion. 
As a consequence, the assembly 16 is positioned as shown in FIG. 13 
defining ladder-like arrays which can extend full height and length in 
lost a form or mold as may be required, the assemblies 16 being contiguous 
or spaced apart and providing both the requisite rigidity and interlocking 
of the entire structure of slabs, reinforcing assemblies, reinforcing bars 
and the like. The key to this interlocking relationship, of course, is the 
cooperation of each vertical frame unit 21 of an assembly 16 with a 
horizontal frame unit rigid with a pair of slabs which are spaced apart by 
it. 
Frame elements 21 of the type shown at 21 also can be used conveniently for 
the fabrication of a lintel. 
As shown in FIGS. 16 and 17, the panels or slabs 1 are provided in addition 
to closure panels or slabs 32 which can be mounted on elements 33 
identical to the connecting elements 15 previously described. The elements 
33 have transverse members which engage the hooks formed on the lower 
transverse members of the elements 21 of assemblies 16 rigid with the 
slabs 1. The closure panels 32 also comprise projections 34 which have 
notches 35 adapted to receive reinforcing bars for the reinforcement of 
the lintel. The ends of the mold at the regions of the openings in the 
wall which are to be formed, namely, windows and doorways, are closed with 
slabs 36 which can be structurally identical to the slabs 1 in the sense 
that they may be composed of cellular synthetic resins provided with a 
reinforcing core, etc. The closure at the end of the mold has been 
represented in FIG. 19 and the slab or end plate 36 has been shown in 
greater detail in FIG. 18. The end plate 36 has a part 37 which projects 
into the space between two slabs 1 and thus engages between the 
confronting faces of these slabs 1. A further part 38 can project 
laterally of the inner fitting part 37 to lie flush with one of the slabs 
1 and define a rabbet 40 in which a window frame, door frame or like 
structure can be received. To permit adjustment of the opening 
accommodating the frame, the plate 36 can be driven in or inserted to a 
greater or lesser extent between the slabs 1. 
We can provide, for example, a plurality of parallel longitudinal grooves 
41 which can be selectively engaged by the transverse members 18, 23 of 
the elements 15, 20. Thus depending upon the groove 41 which is thus 
engaged, the part 37 of the plate 36 can be held more or less deeply in 
the mold. FIG. 20 shows a plate 36 having three grooves 41, the transverse 
member 18, 23 engaging in the middle groove. In order to insure a flush 
connection for the part 29 which lies against the end of a slab 1, grooves 
42 can be provided to show lines along which materials can be removed from 
this projection portion for the various depths of insertion of the part 
37. These parts can be cut away by a simple construction knife or blade 
because of the softness of the foam material, or by a saw. 
FIG. 21 shows a corner of a mold constructed with several tiers and in 
which a corner member 43 is provided to hold the assembly together. In 
this case, the piece 43 forms a passage through which an assembly of 
vertical reinforcing rods 47 can extend as a columnar reinforcement and 
ladder arrays project along each of the walls of the column, members 44 
and 45 representing longitudinal members of the connecting element while 
members 46 represent the transverse members thereof. Otherwise the element 
43 functions in the manner previously described with respect to the other 
connecting elements as to how it can engage the slabs.