AU2020100502A4 - A Modular System for Forming Stairs - Google Patents

Abstract

Abstract A Modular System for Forming Stairs The present invention relates to a modular system for forming concrete stairs. The system has at least one stair formwork module for connecting to an adjacent stair formwork module and/or a pre-formed landing. Each stair formwork module consists of a stair former to be retained in the concrete body of the set of stairs and one or more parallel frames extending transverse within the stair former and allowing the free spreading of concrete to be introduced into the space of the stair former. At least one locating and/or fastening formation is located on each frame to facilitate locating and/or fastening to another frame and at least one aperture is located in each frame for receiving therethrough a reinforcing member. C)

Description

FIELD OF THE INVENTION

The present invention relates to a modular system for forming stairs. In particular, the present invention has particular although not exclusive application to installation of concrete stairs in commercial and domestic buildings.

BACKGROUND OF THE INVENTION

It should be noted that reference to the prior art herein is not to be taken as an acknowledgement that such prior art constitutes common general knowledge in the art.

In the construction of multi-floor structures, concrete stairways are a preferred means for providing access to the vertically spaced apart floors. Concrete is used for building such stairways because it is strong, robust, durable, and requires little maintenance. Traditionally, when concrete, or similar formable or settable material is used to construct stairs, the stairs are either “cast-in-place”, which is an expensive and time consuming process, or a single run of stairs is “pre-cast” and the entire unit is installed after fabrication.

The single run of stairs is formed using permanent formwork systems that are fully assembled as a complete unit for a single run of stairs. In practice, large transport and lifting machinery is required to deliver and install the formed staircase in place. In some cases, the machinery is hired which results in the rushing of the stair installation compromising the quality of the installation.

Clearly it would be advantageous if a modular system for forming stairs could be devised that helped to at least ameliorate some of the shortcomings described above. In particular, it would be beneficial to provide a means for installing stairs without requiring large transport and lifting machinery.

SUMMARY OF THE INVENTION

In accordance with a first aspect, the present invention provides a modular system for forming a set of concrete stairs, the system comprising: at least one stair formwork module for connecting to an adjacent stair formwork module and/or a pre-formed landing, each stair formwork module comprising: a stair former to be retained in the concrete body of the set of stairs; one or more parallel frames extending transverse within the stair former and allowing the free spreading of concrete to be introduced into the space of the stair former; at least one locating and/or fastening formation on each frame to facilitate locating and/or fastening to another frame; and at least one aperture located in each frame for receiving therethrough a reinforcing member.

Preferably, each parallel frame may comprise a pair of complementary locating and/or fastening formations located on opposite sides of the frame, each pair of formations allowing an adjacent frame within another formwork module to connect to form a pair of stairs within a set of stairs.

Preferably, each parallel frame may be a plastic frame formed with an endless perimeter with one or more supports adapted to allow the frame to be secured to the stair former.

Preferably, each formwork module may include a stair former for forming at least one stair using the concrete, and one or more frames for locating within the stair former. Each formwork module may form a single stair of a staircase. Each formwork module may weigh less than 15kg, and preferably between 11 and 12 kg.

Preferably, the formations may include complementary hooks and recesses located on opposite sides of the frame. Alternatively, the formations may include a pair of hooks on one side of the frame and a pair of recesses on the opposite side of the frame. Each frame may be formed as a substantially hollow lattice frame with reinforcing members extending from a central point on each frame.

Preferably, the stair former may be formed using sheet metal. Each stair former may comprise a sloping base extending between opposing ends and a partially open front side.

Preferably, at least two sides of each frame may be secured to the stair former. Preferably one side of the frame may be secured to the base and another side of the frame may be secured to the front side of the stair former. Preferably, the frames may be secured to the stair former by fasteners.

Preferably the reinforcing member passing through the at least one aperture in each frame may be a piece of rebar. The piece of rebar may be positioned to pass through all of the frames within the stair formwork module.

Preferably, the system may further include fasteners for fastening the adjacent modules together. The fasteners may be threaded. The system may further include props for propping the stair formwork modules when pouring the concrete.

Preferably, the pre-formed landing to be fastened to the stair formwork module may include a temporary panel for being removed upon curing of poured concrete in the landing formwork module. The temporary panel may form locating and/or fastening formations in concrete poured into the landing formwork. The formations may facilitate fastening with formations of the stair formwork module. The temporary panel may include plugs which remain behind in the cured concrete to facilitate fastening to a stair formwork module. The temporary panel may include rebar-location protrusions for leaving imprints in the cured concrete indicating the location for securing rebar into the landing.

Preferably, the temporary panel may be formed as a tapered panel or have a bevelled engagement surface.

In accordance with a further aspect, the present invention provides a stair formwork module for locating and fastening to adjacent stair formwork modules and/or a pre-formed landing to form a concrete set of stairs, the stair formwork module comprising: a stair former to be retained in the concrete body of the set of stairs; one or more parallel frames extending transverse within the stair former and allowing the free spreading of concrete to be introduced into the space of the stair former, each frame having at least one locating and/or fastening formations to facilitate locating and/or fastening to another frame in an adjacent stair formwork module; and at least one aperture located in each frame for receiving therethrough a reinforcing member.

In accordance with a still further aspect, the present invention provides a method of manufacturing a set of concrete stairs, the method comprising the steps of: providing one or more stair formwork modules for connecting together to form the set of stairs; removing a temporary panel from a stair connecting end of an upper pre-formed landing module; locating and fastening a first stair formwork module to the upper landing module; connecting and fastening together further stair formwork modules to form the set of stairs; removing a temporary panel from a stair connecting end of a lower pre-formed landing module; locating and fastening an end stair formwork module to the lower landing module; and pouring concrete into the stair formwork modules to form the set of stairs.

According to another aspect of the present invention, there is provided a modular system for forming stairs, the system including: stair formwork modules for fastening together; and concrete for pouring into the stair formwork modules.

Advantageously, the modular system of the preferred embodiment enables the stair formwork modules to be easily carried and lifted in place by a single worker for fastening together in situ on site, prior to pouring the concrete, thereby not requiring the large transport machinery or crane time on site.

Preferably, the formwork modules remain in place after curing of the concrete forming a permanent part of the stairs.

Each formwork module may include: a stair former for forming at least one stair using the concrete; and one or more frames for locating within the stair former.

Each formwork module may form a single stair of a staircase. Each formwork module may weigh less than 15kg, and preferably between 11 and 12 kg.

The frames may be parallel and extend transverse the stair former. Each frame may include locating and/or fastening formations to facilitate locating and/or fastening to another frame. The formations may be located on opposite sides of the frame. The formations may form a complementary fit. The formations may include hooks and recesses. Each frame may be hollow. Each frame may include an endless perimeter, and one or more supports extending across the perimeter. Each frame may include one or more cradles for cradling rebar. Each frame may be formed from plastic.

The stair former may be formed using sheet metal. Each formwork module may further include rebar received within the stair former. The rebar may pass through the frames.

The system may further include fasteners for fastening the modules together. The fasteners may be threaded. The system may further include props for propping the stair formwork modules when pouring the concrete.

The system may further include a landing formwork module for forming a landing to be fastened to a stair formwork module. The landing formwork module may include a temporary panel for being removed upon curing of poured concrete in the landing formwork module.

The temporary panel may form locating and/or fastening formations in concrete poured into the landing formwork. The formations may facilitate fastening with formations of the stair formwork module. The temporary panel may include plugs which remain behind in the cured concrete to facilitate fastening to a stair formwork module. The temporary panel may include rebarlocation protrusions for leaving imprints in the cured concrete indicating the location for drilling of holes to insert rebar. The temporary panel may taper or form a bevelled engagement surface.

According to another aspect of the present invention, there is provided stairs including the modular system, in situ.

According to another aspect of the present invention, there is provided a building including the modular system.

According to another aspect of the present invention, there is provided a method for manufacturing stairs, the method involving: fastening stair formwork modules together; and pouring concrete into the stair formwork modules.

According to another aspect of the present invention, there is provided a frame for a formwork module used in forming stairs, the frame defining: fastening formations to facilitate fastening to another frame.

Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred features, embodiments and variations of the invention may be discerned from the following detailed description which provides sufficient information for those skilled in the art to perform the invention. The detailed description is not to be regarded as limiting the scope of the preceding summary of the invention in any way. The detailed description will make reference to a number of drawings as follows:

Fig. 1 is a rear perspective view of a stair formwork module for forming stairs in accordance with an embodiment of the present invention;

Fig. 2 is a front perspective view of a stair formwork module of Fig. 1;

Fig. 3 shows the rear perspective view of a stair former of Fig. 1;

Fig. 4 illustrates a perspective view of one of the frames of Fig. 1;

Fig. 5 is a side perspective view showing interlocking frames of adjacent stair formwork modules;

Fig. 6 illustrates a perspective view of a set of stairs formed from the connection of stair formwork modules of Fig. 1 and connected to preformed landings at the top and bottom of the stair system;

Fig. 7 shows a perspective view of a temporary panel connected to a pre-formed landing;

Fig. 8 shows a side perspective view of the temporary panel of Fig. 7;

Fig. 9 shows another side perspective view of the temporary panel of Fig. 7;

Fig. 10 is a perspective view of a stair formwork module for forming stairs in accordance with a further embodiment of the present invention;

Fig. 11 is a perspective view of a modular system for forming stairs with the stair formwork module of Fig 10;

Fig. 12 is a side view showing interlocking frames of adjacent stair formwork modules of Fig. 10;

Fig. 13 is a perspective view of a temporary panel of a lower landing formwork module of the system of Fig. 11; and

Fig. 14 is a perspective view of a temporary panel of an upper landing formwork module of the system of Fig. 11.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The following description, given by way of example only, is described in order to provide a more precise understanding of the subject matter of a preferred embodiment or embodiments.

The present invention has been designed to provide a modular system for forming concrete stairs, and in particular, although not exclusive application to installation of concrete stairs in commercial and domestic buildings.

In its broadest form a stairway, staircase, stairwell, flight of stairs, or simply stairs, is defined as a construction designed to bridge a large vertical distance by dividing it into smaller vertical distances, called steps. Therefore a staircase could be formed from at least one step or multiple steps connected to a pre-formed landing at the top and bottom of the staircase.

As illustrated in Figs. 1 and 2 the stair formwork module 10 forms the basic unit for forming a step in the modular system in accordance with an embodiment of the present invention. Each stair formwork module 10 includes a stair former 20 for forming a single stair of a staircase when using the contained concrete. The stair former 20 is formed using sheet metal, and is folded to the required shape with appropriate cut outs and holes to facilitate connection and concrete placement through the assembled stair run. The stair former 20 has a base 21 extending between a pair of ends 22, 23. The front 24, 29 of the stair former 20 forms a partially open surface which allows the connecting formations 46 of the frames 40 to project through the opening 29 to allow connection to another frame 40. When correctly positioned within a set of stairs the base 21 is positioned to form the sloping bottom of the staircase which ensures that the top of the stair former 20 or the part of the completed staircase that is stepped on is correctly positioned.

The spaced apart frames 40 are located within the stair former 20. The frames 40 are positioned parallel to and extend transverse to the elongate front surface 24, 29 of the stair former 20. The stair formwork module 10 further includes rebar 60 that passes through apertures 45 in each frame 40 within the stair former 20.

Each frame 40 is fixed to the sheet metal stair former 20 with mechanical fasteners and adhesives. Fig. 3 shows a stair former 20 with the frames 40 and rebar 60 removed for clarity. The base 21 has tabs 30 with apertures for receiving fasteners therein for connection to pads 48 on each frame 40. The rear side of the base 21 and the ends 22, 23 have a flange 27 with spaced apart apertures 28 for receiving fasteners to allow the stair former 20 to be secured to an adjacent stair former 20. Likewise, the front side of the base 21 and the ends 22, 23 have a flange 26 with spaced apart apertures 28 for receiving fasteners to allow the stair former 20 to be secured to an adjacent stair former 20. A reinforcing member 25 extends across the top side of the front 24. The stair former 20 also has apertures 31 located in spaced apart lines in the front surface 24 for receiving fasteners therein. The fasteners connecting and securing through apertures 47 in the flange 43 on each frame 40 to the stair former 20. Before securing the frames 40 into the stair former 20, adhesive is applied to the flange 43 and the base 44 of each frame 40 to aid in securing the flange 40 in place within the stair former 20.

Each formwork module 10 weighs less than 15kg, and preferably approximately between 11 and 12 kg so as to be easily handled by a single installer complying with safety requirements. Each formwork module 10 is smaller than traditional construction components allowing installation to difficult or tight space areas on a jobsite or jobsites that do not have crane lifting facilities.

As illustrated in Fig. 4, each molded plastic frame 40 includes a tonguein-groove type fastening formations 46, 46A to facilitate fastening to another adjacent frame 40. The formations 46, 46A are located on opposite sides of the frame 40 and form a complementary fit when the hooked tongues 46A are snugly received in the groove recesses 46. Each frame 40 is substantially hollow, including an endless perimeter 41, and a cross-support 42 extending in two dimensions across the perimeter 41. Each frame 40 includes an aperture 45 for allowing the rebar 60 to pass therethrough. The apertures 45 in each frame 40 position the rebar 60 at the correct suspension distance from the external surface prior to the pouring of the concrete. The frames 40 are formed from eco-friendly recyclable plastic.

As shown in Fig. 5, the formations 46, 46A enable preliminary interconnection of adjacent stair formwork modules 10 at a correct spacing and orientation resulting in an accurate final stair run design compliant to all required design regulations. As described above in relation to Fig. 3, in addition to the fastening formations 46, 46A the system further includes threaded screw fasteners for fastening the stair formwork modules 10 together prior to filling with concrete. Furthermore, the system includes props (not shown) for propping interconnected stair formwork modules 10 when pouring the concrete. Formwork props are simply any type of adjustable steel prop used for the temporary supporting the concrete formwork.

According to an embodiment of the present invention, there is provided a modular system 70 for forming stairs as shown in Fig. 6. The system 70 includes multiple stair formwork modules 10 for fastening together. Further, the system includes a lower landing formwork module 80 and an upper landing formwork module 81 for forming respective landings to be fastened to the stair formwork modules 10. Concrete is poured into each module 10, 80, 81 to form the stairs, as described in detail below.

The modular system 70 enables the modules 10, 80, 81 to be easily carried and lifted in place by a single worker for fastening together in situ on site, prior to pouring the concrete, thereby not requiring the large transport machinery or crane time on site. The modules 10 remain in place after curing of the concrete forming a permanent part of the flight of stairs. The stairs are quick to install at low cost.

According to another embodiment, in some installations the lower and upper landings 80, 81 are pre-formed prior to installing the multiple stair formwork modules 10. In this embodiment, when the lower and upper landing formwork modules 80, 81 are pre-formed with concrete a temporary panel 85 is inserted onto the end face of each landing prior to the pouring of concrete. As illustrated in Figs. 7 to 9 the temporary panel 85 is secured to the lower and upper formwork modules 80, 81 by fasteners passing through apertures 91. Once the landing concrete has cured the temporary panel 85 can be removed to allow the connection of the adjacent stair formwork modules 10.

The temporary panel 85 includes masonry plugs 90 which remain behind in the cured landing concrete to facilitate fastening to a lower or uppermost stair formwork module 10. The position of the plugs 90 line up with holes 28 of the stair formwork module 10 for easy mounting and screw fixing. This feature eliminates the requirement for drilling the pre-formed slab after the concrete has cured to mount the stair formwork module 10. Accordingly, fewer tools are required to install the stair system 70 thereby increasing the speed of installation and further reducing the risks of silicosis from drilling cured concrete. The temporary panels 85 have a bevelled engagement body 86 which tapers from the top edge 89 to the bottom edge 92 of the temporary panel 85.

The temporary panel 85 also has protrusions 88 forming voids in the cured concrete for receiving the formations 46A of the stair formwork module 10 when connected to the pre-formed upper landing. Likewise, the protrusions 88 form voids in the pre-formed lower landing for receiving the formations 46 of the stair formwork module 10. The temporary panels 85 also include rebar-location protrusions 87 for leaving imprints in the cured landing concrete indicating the location for inserting and gluing rebar. This feature reduces location error in the installation of the reinforcing bars. The length of these reinforcing bars will be half the length of the stair run plus 300 mm, thereby allowing for shorter lengths of bar being able to be easily handled and manoeuvred around tight worksites and stairwells. Again, this reduces the weight of components for the abovementioned person lifting safety.

Figs. 10 to 14 illustrate a further embodiment of the present invention. Turning to Fig. 10, each stair formwork module 102 includes a stair former 200 for forming a single stair of a staircase using the contained concrete. The stair former 200 is formed using sheet metal, and is folded to the required shape with appropriate cut outs and holes to facilitate connection and concrete placement through the assembled stair run.

The stair formwork module 102 also includes spaced apart frames 202 which are located within the stair former 200. The frames 202 are parallel and extend transverse the elongate stair former 200. The stair formwork module 102 further includes rebar 204 that passes through the frames 202 within the stair former 200.

The internal plastic frames 202 are fixed to the sheet metal stair former 200 with mechanical fasteners and adhesives. Each formwork module 102 weighs less than 15kg, and preferably between 11 and 12 kg so as to be easily handled by a single installer complying with safety requirements. Each formwork module 102 is smaller than traditional construction components allowing installation to difficult or tight space areas on a jobsite or jobsites that do not have crane lifting facilities.

According to this further embodiment of the present invention, there is provided a modular system 100 for forming stairs as shown in Fig. 11. The system 100 includes three stair formwork modules 102 for fastening together. Further, the system includes a lower landing formwork module 104 and an upper landing formwork module 106 for forming respective landings to be fastened to the stair formwork modules 102. Concrete is poured into each module 102, 104, 106 to form the stairs, as described in detail below.

Advantageously, the modular system 100 enables the modules 102, 104, 106 to be easily carried and lifted in place by a single worker for fastening together in situ on site, prior to pouring the concrete, thereby not requiring the large transport machinery or crane time on site. The modules 102 remain in place after curing of the concrete forming a permanent part of the flight of stairs. The stairs are quick to install at low cost.

The lower landing formwork module 104 and an upper landing formwork module 106 have temporary panels 108, 110 shown in Figs. 13 and 14 respectively to facilitate assembly of the stairs. The temporary panels 108, 110 will also be described in greater detail below.

Turning to Figure 12, each molded plastic frame 202 includes tongue-ingroove fastening formations 300 to facilitate fastening to another adjacent frame 202. The formations 300 are located on opposite sides of the frame 202 and form a complementary fit when the hooked tongues are snugly received in the groove recesses.

Each frame 202 is hollow, including an endless perimeter 302, and a cross-support 304 extending in two dimensions across the perimeter 302. Each frame 202 includes a pair of central cradles 306 for cradling the rebar 204 at the correct suspension distance from the external surface prior to the pouring of the concrete. The frames 202 are formed from eco-friendly recyclable plastic.

The formations 300 enable preliminary interconnection of the stair formwork modules 102 at a correct spacing and orientation resulting in an accurate final stair run design compliant to all required design regulations. In addition to the fastening formations 300, the system 100 further includes threaded screw fasteners for fastening the stair formwork modules 102 together prior to filling with concrete. Furthermore, the system 100 includes props (not shown) for propping interconnected the stair formwork modules 102 when pouring the concrete.

As shown in Figs. 13 and 14, the landing formwork modules 104, 106 include temporary panels 108, 110 for being removed upon curing of poured concrete in the landing formwork modules 104, 106. The temporary panels 108,110 taper and form a bevelled engagement surface with the stair formwork modules 102. Alternatively, the modules 108, 110 may be replaced by a single panel incorporating all of the features of the panels 108, 110.

Turning to Fig. 13, the lower temporary panel 108 includes masonry plugs 400 which remain behind in the cured landing concrete to facilitate fastening to a lower stair formwork module 102. The position of the plugs 400 line up with holes of the stair formwork module 102 for easy mounting and screw fixing. This feature eliminates the requirement for drilling the slab after the concrete has cured to mount the stair formwork module 102. Accordingly, less tools are required to install the system 100 thereby increasing the speed of installation and further reducing the risks of silicosis from drilling cured concrete.

Turning to Fig. 14, the upper temporary panel 110 has protrusions 500 forming fastening formations in concrete poured into the landing formwork module 106. These formed fastening formations facilitate fastening with the fastening formations 300 of the upper stair formwork module.

The temporary panels 108, 110 can also include rebar-location protrusions for leaving imprints in the cured landing concrete indicating the location for inserting and gluing rebar. This feature reduces location error in the installation of the reinforcing bars. The length of these reinforcing bars will be half the length of the stair run plus 300 mm, thereby allowing for shorter lengths of bar being able to be easily handled and manoeuvred around tight worksites and stairwells. Again, this reduces the weight of components for the abovementioned person lifting safety.

A method for manufacturing stairs using the system 70, 100 is now briefly described. As described above a set of concrete stairs can be produced by one of two methods. In the first method, stair formwork modules 10, 102 can be fastened together including both lower and upper landing formwork modules forming respective landings. The lower and upper landing formwork modules are fastened to the stair formwork modules 10, 102. Concrete is poured into each module to form the stairs. In a second method, the upper and lower landings may be pre-formed with concrete using the temporary panels 85, 108,

110.

The second method will be described in relation to the forming of the system 70 as illustrated in Fig. 6. Initially, the temporary panels 85 are placed in the landing formwork modules 80, 81 to form the landing slab formwork where the stairs are to be connected during the formwork stage. After both concrete landing slabs have been poured and cured, the temporary panels 85 are removed with the formwork of the landing slabs. The masonry plugs 90 remain in the landing slabs for the connection of the end stair formwork modules 10. Rebar-location imprints are left behind in the slab edges to assist in the locating the reinforcing starter bars. Also, imprint voids from the protrusions 88 are formed in the cured concrete for receiving the formations 46A of the stair formwork module 10 when connected to the pre-formed upper landing and imprint voids from the protrusions 88 are formed in the cured concrete in the pre-formed lower landing for receiving the formations 46 of the stair formwork module 10.

Horizontal reinforcing bars are inserted into the connection edges of the upper and lower floor slabs as set out by the imprints (as per engineering design) leaving the bars to protrude 600 mm into the stair void for later connection of the longitudinal reinforcing bar 60 in the stair formwork modules

10.

Install the topmost stair formwork module 10 from the top landing down. Slide the stair formwork module 10 over the protruding horizontal reinforcing bars and fix the module 10 with screws to the landing slab edge in the correct position dictated by the locating formations 46A on the internal plastic frames

40.

Serially install the next step stair formwork module 10 down in the run.

After the third formwork module 10 has been installed for the required flight of stairs temporary propping may now support the partially constructed system of run of stairs.

Install the remaining stair formwork modules 10, all but the last three from the bottom. Further temporary propping is provided under the bottom surface of the stair formwork modules 10 to prevent the stair formwork modules 10 from moving or sagging.

Install the horizontal reinforcing bars into the lower landing slab edge to mirror the top slab following the hole impressions left by the lower temporary panel 85.

Slide the remaining lowermost three stair formwork modules 10 over the lower reinforcing bars, fixing the modules 10 together but not fixing the last module 10 to the landing slab.

Once the last three modules 10 are over the horizontal reinforcing bars, lift the third module 10 and fourth module 10 up and lower down together for the locating formations 46, 46A to engage. Fix modules three and four together with the screws.

Fix the last module 10 to the landing slab into the masonry plugs 90 left in the slab from the temporary panel 85, as detailed above.

Position the internal longitudinal reinforcing bars 60 into their final position to meet the lower 600 mm horizontally protruding reinforcing bars from the lower landing slab. Tie the reinforcing bars in place as per structural requirements.

Prop the stair run formwork on the under-side of the modules 10 ensuring that the modules are straight and in the correct position prior to pouring concrete into the stair formwork modules 10 to complete the staircase system 70.

A person skilled in the art will appreciate that many embodiments and variations can be made without departing from the ambit of the present invention.

In one embodiment, the landings may form part of a floor slab of the building. The first and last stair formwork modules 10, 102 in a run of stairs can either be mounted to the side, edge or floor surface of the concrete slab landings dependent of the requirements of the project and Architect’s design. The shape can be modified to suit each application.

The stair formwork modules 10, 102 can be made to any width and height to suit the project requirements. The shape and size is variable for manufacture.

An alternative to individual stair formwork modules 10, 102 is having several adjacent stair formwork modules 10, 102 factory connected as a multi step unit essentially being a larger modular unit consisting of several step treads.

An alternative to using sheet metal steel for the stair formwork modules 10, 102 can be: aluminium, ceramics, alternative plastics, composite and hybrid materials, fabric materials, glass reinforced plastics or a lightweight concrete or ‘Hebei’ style products, really anything with a similar structural integrity and material density to perform the same function.

An alternative material to the plastic internal frame 40, 202 would also be the materials in the list above.

An alternative to the connection formations 46, 46A, 300 on the plastic frames 40, 202 would be a separate mechanical fixing or clip, integrated dowel and hole connection detail designed into the frame 40, 202, adhesive or glue connection, or a welded or fused connection.

ADVANTAGES

The present invention relates generally to a modular system for forming stairs, and in particular, although not exclusive application to installation of concrete stairs in commercial and domestic buildings.

Advantageously, the modular system enables the formwork modules to be easily carried and lifted in place by a single worker for fastening together in situ on site, prior to pouring the concrete, thereby not requiring the large transport machinery or crane time on site. The formwork modules remain in place after curing of the concrete forming a permanent part of the flight of stairs. The stairs are quick to install at low cost.

Another advantage of the present invention is the use of the temporary panel including the masonry plugs which remain behind in the cured landing concrete to facilitate fastening to a lower or uppermost stair formwork module. The position of the plugs line up with mounting holes in the stair formwork modules for easy mounting and screw fixing. This feature eliminates the requirement for drilling the pre-formed slab after the concrete has cured to mount the stair formwork module. Accordingly, fewer tools are required to install the stair system thereby increasing the speed of installation and further reducing the risks of silicosis from drilling cured concrete.

VARIATIONS

It will be realized that the foregoing has been given by way of illustrative example only and that all other modifications and variations as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein defined in the appended claims.

As used herein the term “and/or” means “and” or “or”, or both.

As used herein “(s)” following a noun means the plural and/or singular forms of the noun.

In this specification, adjectives such as first and second, left and right, top and bottom, and the like may be used solely to distinguish one element or action from another element or action without necessarily requiring or implying any actual such relationship or order. Where the context permits, reference to an integer or a component or step (or the like) is not to be interpreted as being limited to only one of that integer, component, or step, but rather could be one or more of that integer, component, or step etc.

The above description of various embodiments of the present invention is provided for purposes of description to one of ordinary skill in the related art. It is not intended to be exhaustive or to limit the invention to a single disclosed embodiment. As mentioned above, numerous alternatives and variations to the present invention will be apparent to those skilled in the art of the above teaching. Accordingly, while some alternative embodiments have been discussed specifically, other embodiments will be apparent or relatively easily developed by those of ordinary skill in the art. The invention is intended to

2020100502 01 Apr 2020 embrace all alternatives, modifications, and variations of the present invention that have been discussed herein, and other embodiments that fall within the scope of the above described invention.

In the specification the term “comprising” shall be understood to have a broad meaning similar to the term “including” and will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. This definition also applies to variations on the term “comprising” such as “comprise” io and “comprises”.

Claims (5)

1. A modular system for forming a set of concrete stairs, the system comprising:

at least one stair formwork module for connecting to an adjacent stair formwork module and/or a pre-formed landing, each stair formwork module comprising:

a stair former to be retained in the concrete body of the set of stairs;

one or more parallel frames extending transverse within the stair former and allowing the free spreading of concrete to be introduced into the space of the stair former;

at least one locating and/or fastening formation on each frame to facilitate locating and/or fastening to another frame; and at least one aperture located in each frame for receiving therethrough a reinforcing member.

2. A modular system as claimed in claim 1, wherein each parallel frame comprises a pair of complementary locating and/or fastening formations located on opposite sides of the frame, each pair of formations allowing an adjacent frame within another formwork module to connect to form a pair of stairs within a set of stairs.

3. A modular system as claimed in claim 1 or claim 2, wherein each parallel frame is a plastic frame formed with an endless perimeter with one or more supports adapted to allow the frame to be secured to the stair former.

4. A stair formwork module for locating and fastening to adjacent stair formwork modules and/or a pre-formed landing to form a concrete set of stairs, the stair formwork module comprising:

a stair former to be retained in the concrete body of the set of stairs;

one or more parallel frames extending transverse within the stair former and allowing the free spreading of concrete to be introduced into the space of the stair former, each frame having at least one locating and/or fastening formations to facilitate locating and/or fastening to another frame in an adjacent stair formwork module; and at least one aperture located in each frame for receiving therethrough a reinforcing member.

5. A method of manufacturing a set of concrete stairs, the method comprising the steps of:

providing one or more stair formwork modules for connecting together to form the set of stairs;

removing a temporary panel from a stair connecting end of an upper preformed landing module;

locating and fastening a first stair formwork module to the upper landing module;

connecting and fastening together further stair formwork modules to form the set of stairs;

removing a temporary panel from a stair connecting end of a lower preformed landing module;

locating and fastening an end stair formwork module to the lower landing module; and pouring concrete into the stair formwork modules to form the set of stairs.