FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003
PROVISIONAL SPECIFICATION
(Se section 10; rule 13)
"AN IMPROVED JOINING MEMBER FOR USE IN A SACRIFICIAL FORMWORK AND A SACRIFICIAL FORMWORK EMBODYING THE JOINING MEMBER FOR
CONSTRUCTION OF STRUCTURES"
Sterling Construction Systems Ltd., of 1st Floor, Ador House, No. 7, K. Dubash Marg, Fort, Mumbai - 400 001, India.
The following specification describes the invention.


An improved joining member for use in a sacrificial formwork and a sacrificial formwork embodying the joining member for construction of structures
FIELD OF THE INVENTION
The invention generally relates to a joining member for use in a sacrificial form work for constructing structures of a variety of shapes and sizes using concrete or other pourable, hardenable materials. The invention also relates to rigid sacrificial form works in which concrete or other pourable, hardenable materials can be poured so as to form structures of a variety of shapes and sizes.
BACKGROUND OF THE INVENTION
An important technique for the construction of durable structures utilizes pourable, hardenable materials to provide structural elements, such as foundations, walls, pillars, beams, floors and similar structural elements. The most common materials used in such techniques are various forms of cementitious concrete. Cements and concretes generally are readily available, cost effective, provide advantageous structural characteristics, can be adapted for a variety of uses and applications, and are well known in the construction field.
The use of cements and concretes as structural building materials further provides many advantages over other building materials. For example, concrete foundations, walls, floors, pillars and beams, structural elements, etc. generally are considered resistant to adverse weather conditions, such as high winds and heavy rains, fire damage, insect damage, fungus damage, mildew damage, and moisture induced rot damage.
Furthermore, cement and concrete structural elements, under most conditions, are very durable and can be used to form structures that provide superior stress and weight bearing properties in a variety of building designs. Concrete materials further may be formed into a wide variety of shapes, forms, applications, and structural elements. This flexibility in use largely is due to the ability to install cement and concrete materials in a liquid, semi-liquid, or slurry state into a forming system where the materials harden and cure in place to form a permanent shape or element. Moreover, a wide variety of reinforcing elements


may be incorporated in the concrete structure, including metal bars, mesh, metal and plastic fibers, pre- and post tensioning systems, etc.
To raise concrete walls, formworks that delimit a volume in which concrete is poured are typically used. Usually, those formworks comprise: two walls placed face to face defining between them an interval where concrete is introducable, and connecting devices holding the walls with the required gauge (distance there-between). For holding these walls a number of different varieties of connecting device(s) have been used.
The formworks that are used for construction can be categorized into two categories namely a reusable formwork and a sacrificial formwork.
The reusable formworks are located at the places where the concrete structure must be constructed. It also is common to place reinforcing metal bars or mesh between the walls for the formwork at various locations which are then embedded in the concrete or cementitious materials to strengthen the resulting structure. After erection of the formwork (optionally having reinforcing metals bars or mesh there-between) a slurry comprising cement and concrete materials are poured between set of opposing walls. After the concrete or other materials are hardened and at least partially cured, the formworks are typically removed from the structures and reused in other installations. The reusable formworks are commonly made of wood, metal or a combination of such materials.
As an alternative to conventional forming systems, there is considerable interest in the use of sacrificial formworks that form permanent or semi-permanent components of the completed structure. The walls of the formwork that are left in place after the concrete hardens provide substantially enhanced insulating characteristics for the structure, reduce moisture passage through the structure walls, provide a substrate into which utility lines and piping can be installed, provide a surface for the attachment of finishes and provide other related benefits.
In sacrificial formworks also, the walls of the formwork maintain their proper position using connecting device(s) which by way of example, can include a combination of metal tie plates between adjacent forms and metal tie rods between opposing forms. Such tie


systems hold the forms in place during the assembly of the forming system and resist the movement of the forms from their proper alignment positions when concrete or other cementitious materials are poured and worked between the forms.
The connecting devices play two important roles namely, enabling the walls of the formwork maintain their proper position both during pouring and working of the cementitious materials there-between and ensuring that the walls of the formwork do not get released from the concrete once the same has set.
It has been found that the structure of the connecting device(s) and the principle of their working decide the failure or the success of the entire form work. Thus, in the past, a number of connecting devices have been introduced in the past. Some of the conventional available connecting devices are described and shown for example in US Patent No. 6880304, US Patent No. 6161361, US Patent No. 5609006, US Patent No. 5592848, US Patent No. 5207045, US Patent No. 3900996 and US Patent Publication No. 2004/0020149. Also, it has been noticed that factors such the ease of constructing the connecting devices, the complexity in the shape of the connecting devices, the cost of the connecting devices etc. play a vital role in deciding the commercial viability of the formwork.
The Inventors have found that the connecting device disclosed (or used) in the above mentioned documents many a times do not stand to the tall claims made therein. Some of the disadvantages which have prohibited their effective use include the difficulty in fabricating the connecting device, the higher cost involved in fabricating the connecting device, the excessive use of metal used in constructing the connecting device, their tendency to show structural weakness at critical points (which could result in reduced load bearing capacity), etc..
Also, it has been observed that the formwork thus prepared is difficult to modify at the site of construction and require special skill in erecting.
Thus, it would be appreciated that a connecting device which improves one or more of the above described problems associated with prior connecting devices will have application in general use, for various construction applications.


For at least the above reasons, there is also a need to provide an improved formwork that can be adapted easily with the prevalent construction techniques similar to conventional forming systems. There further is a need for providing a formwork which utilizes rigid panels which can be supplied in generally generic, standard shapes and dimensions. There also is a need to provide a formwork that are readily adaptable for use in circumstances where fire resistance, insect and/or pest resistance, impact resilience, form removability, high energy efficiency, and flexibility to accommodate changes in material availability and cost is important. In addition, there is a need for a forming system that can be relatively simply adapted at the work site for a variety of shapes and applications, including relatively simple to construct corner assembly and easily adaptable corner assemblies of a variety of corner angles, as well as a variety of curved wall corner shapes. Moreover, there is a need for a forming system that provides a versatile wall construction that can be relatively easily adapted to a variety of post-forming construction and wall treatment techniques or that requires minimal post-forming construction and wall treatment techniques.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a connecting device made of metal for use in a sacrificial formwork.
It is an object of the invention to provide a pre-fabricated formwork for constructing concrete or cementitious structures of a variety of shapes and sizes that offer a smooth surface and are suitable for high standard finishes such as tape set jointing and painting or texture coating on at least one of the surfaces.
It is another object of the present invention to provide a prefabricated formwork for constructing concrete or cementitious structures which provide low thermal conductance, low-water absorbance and good acoustic quality.
It is yet another object of the present invention to provide a pre-fabricated formwork for constructing concrete or cementitious structures which can optionally act as load-bearing structures.


It is yet another object of the present invention to provide a pre-fabricated formwork for constructing concrete or cementitious structures which act as load-bearing structures and which can be constructed at low cost without compromising on the structural requirements.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
In the drawings accompanying the specification,
Figure 1(a) represents a perspective view of the metallic composite joining member in
accordance with an embodiment of the present invention;
Figure 1 (b) represents a rear view of the metallic composite joining member in
accordance with an embodiment of the present invention;
Figure 1 (c) represents a front view of the metallic composite joining member in
accordance with an embodiment of the present invention;
Figure 2 represents a sacrificial formwork prepared in accordance with a first
embodiment of the present invention;
Figure 3 represents a sacrificial formwork prepared in accordance with a second
embodiment of the present invention; and
Figure 4 represents a sacrificial formwork prepared in accordance with a third
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention achieves the above objects, among others, by providing, in an embodiment, a metallic composite joining member for use in a sacrificial formwork for constructing structures of a variety of shapes and sizes using concrete or other pourable, hardenable materials.
In another embodiment, the metallic composite joining member comprises a flange comprising a base portion (or front face) and a pair of opposing arm portions (or lateral faces) depending away from the base portion and each of the said arm portions including an inwardly turned lip (a rear face) such that a cavity is created between the base portion and the inwardly turned lips, the base portion comprising at least one an area from where a quadrilaterally shaped metal piece has been removed, at least part of the said at least one quadrilaterally shaped metal piece thus removed from the base portion being joined


between the inwardly turned lips. Further, each of the inwardly turned lips (rear faces) is cross joined to the lateral face opposite thereto or to the base portion so as to have a "X'' shaped joining there-between. In yet another embodiment of the present invention, the location(s) where the said at least one quadrilaterally shaped metal piece is joined between the inwardly turned lips is such that it does not completely overlap with the at least one an area on the base portion from where the quadrilaterally shaped metal piece has been removed. In still another embodiment of the present invention, the base portion is additionally provided with at least one groove for accommodating reinforcing metal bar(s). In one more embodiment of the present invention, one or more blocks of insulative material such as polyurethane or expanded polystyrene is located in the cavity created between the base portion and the inwardly turned lips.
It is envisaged that locating one or more blocks of insulative material in the cavity created between the base portion and the inwardly turned lips of the composite joining member would impart thermal insulation to the concrete or cementitious structures thus constructed in addition to reducing the cost of construction of the concrete or cementitious structure.
The present invention also provides a sacrificial formwork for constructing concrete or cementitious structures of a variety of shapes and sizes that offer a smooth surface and are suitable for high standard finishes such as tape set jointing and painting or texture coating on at least one of the surfaces, said formwork comprising two walls formed of pre-fabricated fibre cement boards placed face to face defining between them an interval where concrete is introducable, and the metallic composite joining member defined above holding the walls with the required gauge (distance there-between).
The construction of the metallic composite joining member is such that comprises a flange comprising a base portion and a pair of opposing arm portions depending away from the base portion and each of the said arm portions including an inwardly turned lip such that a cavity is created between the base portion and the inwardly turned lips, the base portion comprising at least one an area from where a quadrilaterally shaped metal piece has been removed, at least part of the said at least one quadrilaterally shaped metal piece thus removed from the base portion being joined between the inwardly turned lips.


Further, each of the inwardly turned lips (rear faces) is cross joined to the lateral face opposite thereto or to the base portion so as to have "X" shaped joining there-between.
Each of the two walls formed of pre-fabricated fibre cement boards of the formwork are joined to each of the opposing arms. The size of the base portion is such that it is almost equal to the required gauge.
In an embodiment of the present invention, one or more blocks of insulative material such as polyurethane or expanded polystyrene is located in the interval between the fibre cement boards. It is envisaged that locating one or more blocks of insulative material in the interval between the fibre cement boards would impart thermal insulation to the concrete or cementitious structure thus constructed in addition to reducing the cost of construction of the concrete or cementitious structure.
In another embodiment of the present invention, at least part of an external surface of at least one fibre cement board is provided with a layer of insulative material such as polyurethane or expanded polystyrene, upon which a further fibre cement board is provided. It is envisaged that providing such layer of insulative material on an external surface of at least fibre cement board would provide additional fire retarding properties to the concrete or cementitious structure thus constructed.
The fibre-cement skins provides a smooth surface and are suitable for high standard finishes such as tape set jointing and painting or texture coating internally and/or externally. These fabricated panels function essentially as permanent formwork for the concrete which is used to fill the void between the studs. The studs have holes at predetermined intervals in a surface opposite to width wise edge surfaces of the wall panels; and steel reinforcement rods can be inserted through these slits to strengthen the concrete core fill, so as to construct a load bearing walls.
One embodiment is a load bearing wall with concrete fill along with eco-form which consists Expanded Polystyrene (EPS) blocks in between the concrete core-fill which reduces the costs and increases durability as against Concrete Hollow Block (CHB) and Pre-cast walls.


Another embodiment is the external insulated load bearing wall which has an insulated EPS layer attached to one of the Fibre Cement Board, which provides low thermal conductance.
FIG 1(a), 1(b) and 1(c) show the composite joining member of the present invention. The front face has a rectangular section cut out. The front face further comprises with a small circular portion cut out at the bottom of the rectangular section to allow the passage of the reinforcement bars. Each of the lateral face is bent to form a pair of rear faces, wherein the rear faces do not come in contact with each other. The rectangular section cut out from the front face is used to join the two rear faces, which is done by welding the rectangular section to the two rear faces. It can be said that the composite joining thus obtained so as to form a box like construction which is open from top and bottom and also substantially open at a rear face and has small sections cut out in the front face. Further, each of the inwardly turned lips (rear faces) is cross joined to the lateral face opposite thereto or to the base portion so as to have "X" shaped joining there-between. In a preferred embodiment, rectangular section cut out from the front face is divided into three strips. A first of the three strips can be used for joining the two rear faces, a second of the three strips can be used for joining a first rear face to the lateral face opposite thereto or to the base portion and the last of the three strips can be used for joining a second of the rear face to the lateral face opposite thereto or to the base portion.
The same arrangement is followed across the whole length of the composite joining member. The composite joining member may be provided with two or more rectangular sections on the front face and two or more places where the two rear faces are welded together using such a rectangular sections.
Since one of the panels of the box shaped is kept empty, the cost of production is brought down significantly. However, this does not compromise on the tension bearing capacity of the studs. Due to the welding of the cut-out sections to the open panel, the capacity to handle the pressure on that side is sustained as well.


As can be seen from figure 2, the formwork comprises two fibre cement boards separated by a determined distance which is maintained by placing two or more composite joining members at regular intervals.
FIG 3 is a diagram of an embodiment of the present invention. It has Expanded Polystyrene (EPS) blocks placed in between two metal studs in random or regular fashion, such that the blocks do not hinder the passage of the reinforcement bars or any other structure which may be used in the said formwork for the purpose of reinforcement (if any). Concrete can be filled within the spaces left. This reduces the cost of the wall to a great extent.
FIG 4 is a diagram for a further embodiment of the invention. The form work comprises three Fibre cement boards. The middle board and a first outer board are separated by a determined distance which is maintained by placing two or more composite joining members at regular intervals, while the middle board and a second outer board are separated by an EPS layer. The EPS layer securely adheres to the board and upon the EPS layer, the second outer board is located and hence, it can be said to be sandwiched between the middle board and the second outer board. The space between the middle board and the first outer board can be filled with cement or concrete or other pourable, hardenable materials to from the concrete or cementitious structure.