FIELD OF THE INVENTION

The invention relates to a step for a staircase, a method of constructing a staircase, a kit for a staircase, and to a staircase.

BACKGROUND

Staircases, or sets of stairs, for use in buildings such as domestic dwellings are typically constructed of timber, which is expensive and may be regarded as environmentally unfriendly. Constructing a set of stairs is a task requiring considerable skill, and generally requires employment, and payment of a skilled tradesman. In some types of building staircases may be of concrete construction, and such staircases, like timber staircases, are typically expensive to construct and must be constructed by skilled tradesmen.

The inventor has discerned that there is a need for steps for use in forming a staircase which can be used in a domestic environment, and a method of constructing a set of stairs which can be used in a domestic environment which is easier to construct than a conventional set of stairs and which can be made from an alternative material . At least preferred embodiments of aspects of the present invention can provide a step for use in constructing a staircase, a kit for constructing a staircase, a staircase and/or a method for constructing a staircase which addresses or at least ameliorates one or more difficulties, inconveniences or expenses involved with constructing a conventional set of stairs, or at least provide a useful alternative.

SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided a step, for use in constructing a staircase, the step comprising: a tread portion; and at least one adjustable spacing mechanism for vertically spacing apart, in use, the tread portion of the step from the tread portion of a similar adjacent step of a set of stairs.

Preferably the step further comprises at least one riser portion, adapted to extend substantially vertically relative to the tread portion, in use.

Preferably the at least one adjustable spacing mechanism is provided on the at least one riser portion.

Preferably the at least one adjustable spacing mechanism is adapted to vertically space apart the tread portion of the step from the tread portion of a similar adjacent step of a set of stairs, when said tread portion if the step is orientated substantially horizontally.

Preferably said tread portion comprises a generally planar tread surface.

Preferably said tread portion is formed from sheet metal . Preferably said tread portion is formed from sheet steel.

Preferably said riser portion is adapted, in use, to extend upwardly relative to said tread portion.

Preferably said adjustment mechanism comprises one or more support elements, moveable relative to the tread member.

Preferably said adjustment mechanism comprises one or more locking members for locking a support element in a desired position relative to the tread member. Preferably said adjustment mechanism comprises one or more support elements, moveable relative to the said riser portion.

Preferably the adjustment mechanism comprises a marked scale for indicating the set vertical spacing between the tread portion of the step and the tread portion of said similar adjacent step which is provided by the adjustment mechanism in any one of a number of stated of adjustment.

Preferably the marked scale indicates the set vertical spacing between the tread portion of the step and the tread portion of said similar adjacent step which is provided by the adjustment mechanism based on the position of the support element relative to the marked scale.

Preferably markings on the scale are provided adjacent a predetermined part of the support element such that the position of said predetermined part of the support element relative to the scale indicates the set vertical spacing between the tread portion of the step and the tread portion of said similar adjacent step.

Preferably the marked scale is provided on the at least one riser portion. Preferably the marked scale is provided by an indicium member.

Preferably the indicium member comprises scale printed thereon.

Preferably the indicium member comprises a sticker.

Preferably said adjustment mechanism comprises one or more locking members for locking a support element in a desired position relative to the riser portion.

Preferably at least one of said locking members is a fixing device adapted to fix the support element relative to the riser portion.

The fixing device may be received in an aperture in the support element.

The aperture in the support element may be an elongate groove.

The fixing device may be received in an aperture in the riser portion.

The aperture in the riser portion may be provided in an attachment plate mounted on the riser portion. The fixing device is preferably operable between a locked configuration in which the support element is locked in position relative to the riser portion and an unlocked configuration in which the support element is able to move relative to the riser portion.

The fixing member may be a threaded fastener. Preferably at least one support element comprises an upper surface adapted, in use, to engage a similar step, located, in use, at a higher height than said step.

Preferably the upper surface of the at least one support member is adapted to engage a tread portion of a similar step. Preferably the upper surface of the at least one support member is adapted to engage a an underside of a tread portion of a similar step.

Preferably the tread portion has a front edge region which is closer to a lower end of the staircase in use, and a rear edge region adapted to be closer to a higher end of the staircase in use.

Preferably, the step comprises a support portion for supporting one of the front and rear edge regions at a predetermined height relative to a vertically corresponding part of an inclined step support member upon which the step can be supported, in use.

Preferably the support portion is adapted to support the rear edge region of the tread portion at a predetermined height relative to a vertically corresponding part of inclined step support member upon which the step can be supported, in use.

Preferably the support portion comprises part of the underside of the tread portion.

Preferably said part of the underside of the tread portion is adapted to be supported directly on inclined step support member, in use.

Preferably the step comprises a front riser portion.

Preferably the front riser portion depends downwardly from the tread portion in use.

Preferably the front riser portion depends downwardly from a front edge of the tread portion in use. In an embodiment the at least one adjustable spacing mechanism is provided on the front riser portion.

Preferably the front riser portion is adapted to be positioned forward of a rear riser portion of a similar lower and more forwardly positioned step in use.

Preferably the front riser portion is adapted to contact a rear riser portion of a similar lower and more forwardly positioned step in use.

Preferably the front riser portion is adapted to be fixed to a rear riser portion of a similar lower and more forwardly positioned step in use.

Preferably the step comprises one or more side panels.

Preferably each of the one or more side panels projects substantially perpendicular to the tread portion.

Preferably each of the one or more side panels depends from a lateral side of the step portion.

Preferably each of the one or more side panels depends downwardly . Preferably the step comprises one or more fixing brackets, each adapted to be attached to an inclined step support member upon which the step can be supported, in use.

Preferably each of the one or more fixing brackets is attached to the tread portion.

Preferably each of the one or more fixing brackets comprises a portion which projects downwardly from the tread portion, in use.

Preferably each of the one or more fixing brackets is attached to an underside of the tread portion.

Preferably each of the one or more fixing brackets is provided on the step spaced apart from a side panel of the step, thereby providing a support member receiving space therebetween, adapted to receive an inclined step support member upon which the step can be supported in use.

Preferably each of the one or more fixing brackets comprises an attachment portion to facilitate attachment to an inclined step support member upon which the step can be supported in use. The attachment portion may comprise one or more apertures for receiving fixings or fasteners such as screws, bolts, rivets or the like.

Preferably each of the one or more fixing brackets projects rearwardly beyond a rear edge region of the tread portion.

Preferably said step has a width direction, corresponding to a width direction of a staircase to be formed by a plurality of steps, and a length direction substantially perpendicular to the width direction.

Preferably the step is dimensioned so that one of a front of the step and a rear of the step, can fit into the other of a front or a rear of an adjacent similar step, in use.

Preferably one of a front of the step and a rear of the step has a smaller lateral width than the other of the front of the step and a rear of the step. Preferably, one or more of the tread portion, a front riser portion and a rear riser portion is formed from sheet metal .

Preferably each of the tread portion, a front riser portion and a rear riser portion is formed from sheet metal. In an embodiment the tread portion, a front riser portion and a rear riser portion are formed from a single piece of sheet metal. In such an embodiment the single piece of sheet metal is formed, for example by folding, to proved the tread portion, a front riser portion and a rear riser portion. In an alternative embodiment two or more of the tread portion, a front riser portion and a rear riser portion may be mutually attached by welding.

In preferred embodiments the step is constructed primarily from sheet metal, most preferably sheet steel.

It is desirable that a sound deadening material be applied to one of more of the steps . It is preferred that sound deadening material be applied to the underside of the tread portion. This can assist in reducing or eliminating drumming and making the staircase feel more like a traditional, e.g. timber staircase.

According to a second aspect of the present invention there is provided a step, for use in constructing a set of stairs, the step comprising: a tread portion; and at least one first riser portion, adapted to extend a desired vertical distance, in a first vertical direction, from said tread portion when the tread portion is orientated substantially horizontally, in order to space apart the tread portion of the step from the tread portion of a similar step by a desired vertical distance; and at least second riser portion, adapted to extend in a second vertical direction, from said tread portion when the tread portion is orientated substantially horizontally; wherein, in use, the first riser portion is adapted to be attached to a second riser portion of another identical step, and the second riser portion is adapted to be attached to a first riser portion of another identical step, in order to fix together the step and the other identical step in forming a staircase.

Preferably, said first riser portion is adapted to overlie and be substantially parallel to said second riser portion of the said other identical step, and said second riser portion is adapted to be overlie and be substantially parallel to said first riser portion of the said other identical step.

Preferably the step in accordance with the second aspect of the invention is in accordance with the first aspect of the invention.

According to a third aspect of the present invention there is provided a method of constructing a staircase comprising: providing at least one step support member adapted to be provided in an inclined orientation in use and to support a plurality of steps; providing a plurality of steps, each having a tread portion adapted to be substantially horizontal in use, each tread portion having a front edge adapted to be closer to a lower end of the staircase in use, and a rear edge adapted to be closer to a higher end of the staircase in use, each step comprising a support portion for supporting one of the front and rear edges at a predetermined height relative to a vertically corresponding part of the at least one support member; providing a plurality of adjustable spacing mechanisms, each for vertically spacing the other one of the front and rear edges of a tread portion vertically relative to a vertically corresponding part of the at least one support member; the method further comprising: fixing the at least one step support member in an inclined orientation; adjusting each adjustable spacing mechanism to a setting in which it is adapted to vertically space apart said other one of the front and rear edges of a tread portion from the at least one support portion so that the tread portion is substantially horizontal; and attaching respective steps to the at least one step support member so that said one of the front and rear edges of the respective tread portion is supported by the respective support portion, so that said other of the front and rear edges is vertically spaced apart from the at least one support member by at least one adjustable spacing mechanism, and so that the tread portion of each step is substantially horizontal. Preferably, at least some of the adjustable support mechanisms are integrally formed with at least some of the steps used to construct the staircase. _ Q —

In a preferred embodiment, each step comprises at least one adjustable support mechanism for supporting the tread portion of the next higher step at a desired ' vertical spacing above the tread portion of said step. Preferably the method further comprises the step of: determining a vertical height over which the staircase is to extend; and calculating a desired vertical spacing between the tread portions of each two adjacent stairs of the staircase to be constructed, said desired vertical spacing being a distance between a minimum vertical spacing and a maximum vertical spacing that can be provided by an adjustable spacing mechanism provided, so that the vertical height over which the staircase is to extend divided by the desired vertical spacing is substantially an integer number.

Preferably the method further comprises the step of: determining the number of steps required to construct the staircase, based on said integer number.

Preferably the method further comprises the step of: determining a horizontal extent over which the staircase is to extend.

Preferably the method further comprises the step of: installing the at least one step support member inclined and extending substantially the determined horizontal extent over which the staircase is to extend.

Preferably the method further comprises the step of: installing said steps, so that the tread portion of each step is vertically spaced apart from the tread portion of an adjacent step by said desired vertical spacing.

Preferably the number of steps is calculated by dividing the vertical height over which the staircase is to extend by a distance which is between the predetermined minimum vertical height and maximum vertical height of the steps. The number of steps required may be n-1, where n is the integer number. In such an embodiment a top unit may provide a rise associated with the height of one step.

Preferably each step of the plurality of steps is in accordance with at least one of the first and second aspects of the invention.

Preferably each step of the plurality of steps has a tread portion which extends a fixed distance in the direction of the length of the staircase, the fixed distance being substantially the same for each step. Preferably the horizontal extent over which the staircase is to extend is determined by multiplying the number of steps required by said fixed distance.

According to a fourth aspect of the present invention there is provided a kit for forming a staircase extending between a lower fixing area and a upper fixing area, comprising: at least one support member adapted to be provided in an inclined orientation in use and to support a plurality of steps; a plurality of steps, each having a tread portion adapted to be substantially horizontal in use, each tread portion having a front edge adapted to be closer to a lower end of the staircase in use, and a rear edge adapted to be closer to a higher end of the staircase in use, each step comprising a support portion for supporting one of the front and rear edges at a predetermined height relative to a vertically corresponding part of the at least one support member; a plurality of adjustable spacing mechanisms, each for vertically spacing the other one of the front and rear edges of a tread portion vertically relative to a vertically corresponding part of the at least one support member .

This allows the tread portion of the step to be oriented substantially horizontally for a variety of angles of inclination of the at least one support member. In an embodiment, at least some of the adjustable spacing mechanisms are integrally formed with at least some of the steps used to construct the staircase.

In such an embodiment the adjustable spacing mechanisms may be considered to have the effect of vertically spacing apart, in use, the tread portion of one step from the tread portion of a similar adjacent step, stairs .

In a preferred embodiment, each step comprises at least one adjustable spacing mechanism for supporting the next higher step.

Preferably each of the plurality of steps is in accordance with at least one of the first and second aspects of the invention.

Preferably the kit comprises a base unit for securing to the lower fixing area.

Preferably the kit comprises a top unit, for securing to the upper fixing area.

Preferably the at least one support member can be arranged to extend between the base unit and the top unit. In an embodiment the at least one support member is adapted to be configured to a desired length.

In an embodiment the at least one support member comprises at least two support members.

In an embodiment the or each support member comprises a metal beam.

In an embodiment the or each support member is in the form of an elongate metal box section.

Preferably the kit further includes a base step which is different in construction to the plurality of steps, and is adapted to engage the base unit and one step of said plurality of steps.

Preferably the kit further includes a top step which is different in construction to the plurality of steps, and is adapted to engage the top unit and one step of said plurality of steps.

Preferably the kit further comprises instructions for construction of a staircase.

Preferably the instructions are for building a staircase in accordance with a method in accordance with the third aspect of the invention.

Preferably the instructions are provided on a machine readable medium.

Preferably the instructions are presented in the form of recorded audio and video.

The instructions may be provided in the form of a DVD. According to a fifth aspect of the invention there is provided a staircase comprising a plurality of steps in accordance with at least one of the first and second aspects, and/or constructed from parts comprising a kit in accordance with the fourth aspect of the invention. According to a sixth aspect of the invention there is provided a staircase constructed by a method in accordance with the third aspect of the invention.

It will be appreciated that integers and features set out in relation to one or more of the aspects of the invention may be incorporated in other aspects.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Fig. 1 is a perspective view from above of an embodiment of a step in accordance with an aspect of the present invention;

Fig. 2 is a plan view from above of the embodiment of Fig. 1;

Fig. 3 is a plan view from below of the embodiment of Fig. 1; Fig. 4 is a side view of the embodiment of Fig. 1;

Fig. 5 is a front elevation of the embodiment of Fig. 1; Fig. 6 is a perspective view from below of the embodiment of Fig. 1;

Fig. 7 is a rear elevation of the embodiment of Fig. 1;

Fig. 7A is a schematic cross sectional view, corresponding to A-A of Fig. 7, of part of the step of Fig. 1;

Fig. 8 illustrates schematically a first step in a method for building a set of stairs;

Figs. 9 and 10 illustrate schematically further steps in a method for building a set of stairs;

Fig. 11 is a schematic cross sectional view of a step of the type illustrated in Figs. 1 to 7;

Fig. 12 is a schematic cross sectional view of a step, for use as the uppermost step in a set of stairs, which has some, but not all of the features of the step of Fig. 11;

Fig. 13 is a schematic cross sectional representation of the part of the method represented in Fig. 10, with a first step, of the type illustrated in Figs. 1 to 7, being used to construct a set of stairs;

Fig. 14 is a schematic cross sectional representation of the a later part of the method, with subsequent steps being added to construct a set of stairs;

Fig. 15 is a schematic cross sectional representation of a completed set of stairs, including a plurality of steps of the type illustrated in Figs. 1 to 7 and 11, and an uppermost step as illustrated schematically in Fig. 12;

Fig. s 16 and 17 are schematic side views of a plurality of steps forming part of a staircase.

Fig. 18 is a partial cross sectional view of a practical embodiment of a staircase. DETAILED DESCRIPTION OF EMBODIMENTS

With reference to Figs. 1 to 7A an embodiment of a step, generally designated 10, for use in constructing a set of stairs or staircase will be described.

The step 10 comprises a tread portion 20 and a height adjustment mechanism 30. In this embodiment the step comprises two height adjustment mechanisms 30, one adjacent each lateral side of the step, for adjusting the distance by which the tread portion 20 is vertically spaced apart from a tread portion of a neighbouring step in use.

The tread portion 20 has a front edge 21 (adapted, in use, to be closer to an adjacent lower step) and a rear edge 22 (adapted, in use, to be closer to an adjacent higher step) , each of which extend across the width of the step 10. More specifically, in this embodiment the tread portion of the next higher step will rest upon the top of the height adjustment mechanisms so that it is vertically spaced apart from the tread of the step 10. It will be appreciated that, in use, the adjustment mechanism effectively vertically spaces apart the tread portion of the next higher step from a runner on which the steps are supported, as will be described in more detail hereafter.

Referring to Figs. 1 to 7A in more detail the step 10 comprises a rear riser portion 40 which extends upwardly from the rear edge 22 of the tread portion 20 and which may be regarded as providing at least part of, and/or being generally equivalent to, a riser of a conventional step in a set of stairs which rises above the tread part. The rear riser portion 40 extends almost the entire width of the step 10 and terminates at either side in a folded back rear riser side portion which descends perpendicular from vertical side edges 43 of the rear riser portion 40. In a preferred embodiment the rear riser portion 40 is formed from sheet steel (as is most of the rest of the step 10) and the rear riser side portions 41 are provided by right angle folds which define rear riser portion side edges 43. The height adjustment mechanisms 30 are mounted to the rear riser portion 40 such that a moveable height adjustment member 31 can be moved to a desired height relative to the rear riser portion 40 (and thus relative to the tread portion 20) and fixed at that height. In the preferred embodiment as best illustrated in Fig.s 7 and 7A each moveable height adjustment member 31 comprises a metal member (in this case a length of angle steel) which is elongate in the height direction in use and which is provided with an elongate groove 32 which extends in the direction of elongation. The moveable height adjustment member 31 can be locked in place relative to the rear riser portion 40 by a bolt 33 the shaft of which extends through the groove and is threaded into a receiving (female threaded) part provided in a mounting plate 36, which is rigidly mounted on the rear riser portion 40. In this embodiment the receiving part comprises a female threaded aperture 37 provided in the mounting plate 36 which is rigidly attached to the rear riser portion 40 close to a lateral side of the step and to the rear riser side portion 41. It will be appreciated that when the bolt 33 is slacked off the moveable height adjustment member 31 can be moved to a desired height (within the confines of the length of the groove 32) relative to the rear riser portion 40. The moveable height adjustment member 31 can then be locked at the desired height by tightening of the bolt 33. In this embodiment, in order to assist a user in setting the height adjustment mechanism 30 to the desired height, a graduated scale 34, for example a scale printed on a suitably located sticker attached to the rear riser portion 40 is provided close to the bottom of the moveable height adjustment member 41. The graduated scale 34 provides indicia in the form of height markings so that the height at which the moveable height adjustment member is set (that is in this embodiment the height of the top of moveable adjustment member 31 above the tread portion 20) is above the level of the tread portion 20 can be read by inspection of the position of the bottom portion 38 of the moveable height adjustment member 31 relative to the scale. For example if it is desired to set the height adjustment mechanism to 175mm, so that the top 35 of the moveable height adjustment member 31 is 175mm above the height of the tread portion, then this can be achieved by aligning the bottom 38 of the moveable height adjustment member 31 with a marking representing 175mm. Of course, other methods of providing a convenient graduated scale may be used. For example, rather than aligning the bottom 38 of the moveable height adjustment member 31 with a mark on the scale a pointer indicium (not shown) may be provided on the moveable height adjustment member for alignment with corresponding markings on the scale 34. In a preferred embodiment the height adjustment mechanism may be set to any setting between 150mm and 185mm above the height of the tread portion 20 although of course other heights and ranges may be implemented as desired.

It will be appreciated that in this embodiment the rear riser side portions 41 extend downwardly somewhat below the level of the tread portion 40 to provide downwardly projecting rear side parts 42.

The step 10 further comprises a front riser portion 50, which in this embodiment is in the form of a rectangular panel which projects perpendicularly downwardly from the front edge 21 of the tread portion 20, which extends substantially the entire width of the step and which projects downwardly (in use) by a distance which is slightly less than the minimum height setting of the height adjustment mechanism 30. The step 10 further comprises tread portion side panels 52 which project downwardly from lateral sides 23 of the tread portion 20. A (lower) front edge 53 of each tread portion side panel 52 is connected along most of its downwardly projecting length to the lateral side of the front riser portion 50. A (shorter) rear edge 54 of each tread portion side panel is attached to a front part of the corresponding rear side part 42 of the rear riser side portion 41. It will be appreciated that the step is slightly wider in the region of the tread portion to side panels 52 than it is in the region of the rear riser side portions 41. The tread portion side panels 52 have respective lower edges 55 which are inclined relative to the tread portion 20 from a lowest extreme at the front of the step which is preferably, in use, a distance below the tread portion 20 corresponding to at least the maximum height of the height adjustment mechanism, and a higher part at the rear of the respective tread portion side panel which is typically only a few centimetres below the level of the tread portion 20.

The step 10 further comprises first and second runner fixing brackets 60 which project downwardly perpendicular to the underside of the tread portion 20. Each runner fixing bracket 60 is located quite close to the lateral edge of the tread portion, but it spaced apart from the corresponding rear side part 42 by a distance which allows a runner (which can be used to support a plurality of steps 10) to fit therebetween.

It will be appreciated that in use a plurality of steps may be used for a staircase (or set of stairs, these terms being used interchangeably herein) . A lower one of two adjacent steps has a front part of the tread portion supported on the tops 35 of suitably adjusted height adjustment mechanisms of a still lower step. The step 10 is also supported, in this embodiment, by engagement of the rear edge 22 of the tread portion with each of a pair of inclined runners which are provided to support the steps. Each runner is located between one of the runner fixing brackets 60 and a corresponding side part of the step, in this embodiment a corresponding rear riser side portion and/or rear side part 42. The parts of the rear edge 22 between the runner fixing brackets 60 and the side parts may be considered to be support portions for supporting a rear of the tread portion of the step on a runner. In Fig. 7 the support portions are designated by the reference numeral 22A.

The height adjustment mechanisms 30 of the step are set to a suitable height and a further, higher identical step can be located so that the front of its tread portion 20 is supported at a desired height by the height adjustment mechanism 30 of the lower step. The rear of the tread portion of the higher step is supported on the inclined runners as described above with reference to the lower step. It will be appreciated that use of a height adjustment mechanism to support a front part of the tread portion, while the rear part of the tread portion is a fixed height above a corresponding part of the runners, allows the step to be arranged so that the tread portion is horizontal for a range of angles of inclination of the runners. Further the fact that this height adjustment effectively allows the height of the steps to be adjusted can facilitate an integer number of steps of equal height being provided in a staircase, without requiring the steps to be specifically manufactured for the desired height of the staircase.

Each step may be regarded as having a front tread portion support portions 28 adjacent the front edge and close to the lateral side of the step, these being, in this embodiment, parts of the underside of the tread portion which engage and are supported by the height adjustment mechanisms of a lower step.

In an alternative embodiment the height adjustment mechanism (s) of each of the intermediate steps may be on the lower riser portion. It will be appreciated that this is an alternative arrangement for allowing the vertical spacing between the tread portions of adjacent steps. In such an alternative the height adjustment mechanism (s) of a given step could, for example, be arranged to engage part(s) of the tread portion of the next lower step, could be arranged to engage one or more of the fixing brackets of the next lower step, or could be arranged to engage one or more other suitable (preferably rearwardly projecting) engagement parts of the next lower step. It will further be appreciated that in a variation in which the adjustment mechanism of a step is provided on the lower riser portion of a step, the adjustment mechanism may be provided with a portion adapted to support the step on (and thereby directly space the tread portion of the step vertically apart from) the runner, adjacent the tread portion of the next lower step: in such a variation it can still be considered that the adjustment mechanism is adapted to adjust the vertical spacing between the tread portion of the steps and the tread portion of the adjacent step.

A method of constructing a staircase or set of stairs in accordance with the present invention will now be described with reference to Figs. 8 to 15. With reference to Fig. 8 a vertical height H is determined which is the desired height of the set of stairs to be constructed. Based on the height H and the characteristics of the steps (for example step 10 as described above) a user can determine a number of steps which can span the desired vertical height H when the vertical distance between the tread portion of each pair of adjacent steps is equal. For example in a preferred embodiment the height adjustment mechanism 30 enables the distance between the tread portions of a pair of adjacent steps to be set at between 150 and 185mm. A number of steps can thus be determined by dividing the height H by a distance between the range 150mm to 185mm to provide an integer number of vertical step heights into which the desired height H can be divided. For example if the vertical height H is 1050mm and the adjustment mechanism allows a height between tread portions of between 150mm and 185mm, then the number of vertical spacings in the set of stairs will be between 5.68 (1050 divided by 185) and 7 (1050 divided by 150) . Thus in this example a user may choose a set of stairs with 7 vertical spacings of 1050mm or with six vertical spacings of 175mm (1050 divided by 6).

Thus, with reference to Fig. 8 a user measures the height between an upper area 101 and a lower area 103 between which it is desired to provide a set of stairs and determines an integer number of substantially equal vertical spacings for steps to be provided therebetween. In this example (for simplicity and ease of illustration) it is assumed that the vertical height is 1050mm and that the user decides to provide six vertical spacings, each of 175mm to bridge this vertical height. The user then determines a horizontal length L over which the staircase will extend. The horizontal length L will be the length of each step (which in this example is assumed to be a uniform 250mm for each step) multiplied by a number equal to the number of vertical spacings minus one (since the set of steps will both begin and end with a rise, and the rise at the top of the staircase is provided without requiring a corresponding step) . Thus in the described example the set of steps will comprise five tread portions each with a length of 250mm to provide a horizontal length L of 1250mm.

A user will then secure a pair of inclined runners which span the vertical height substantially between the tread portion of the top step and the lower area 103 and the horizontal length L.

A preferred arrangement for securing inclined runners is illustrated in Fig. 9. As illustrated in Fig. 9 an arrangement for securing the bottom of each of a pair of inclined runners at a lower area 103 comprises a base unit 110. The base unit 110 comprises a bottom plate 111 in the form of a rectangular sheet metal panel adapted to lie upon the horizontal surface of the lower area 103 and to be firmly attached thereto for example by battens. The base unit 110 further comprises a substantially vertical front riser panel 112 which in use extends substantially vertically from an elongate front edge of the bottom plate 111 (and in use is substantially parallel to the riser portions of steps in the constructed set of steps) . The base unit 110 further comprises first and second rectangular lateral side panels 113 which act as webs between the bottom plate 111 and the front riser panel 112. The base unit further comprises first and second side fixing plates 114 which are substantially parallel to the lateral side panels and spaced apart to allow inclined runners to fit snugly therebetween. The side fixing plates 114 are preferably welded to the bottom plate 111 and the front riser panel 112.

The base unit 110 further comprises first and second height adjustment mechanisms 116 which are analogous and similar in construction to the height adjustment mechanisms 130 described above and which are provided in order to vertically space the tread portion of a first lowest step of a set of steps from the floor level of the lower area 103 and also from a frontmost portion of an inclined runner. It will be appreciated that the bottommost part of each of a pair of inclined runners can be secured to the lower area 103 by attachment to the base unit 110. More specifically the bottom end of each runner is placed between a side fixing plate 114 and a lateral side panel 113 of the base unit 110 and can be fixedly attached thereto, for example by use of suitable screws or other fixing elements (such as rivets or the like) .

As illustrated in Figs. 9 and 10 an upper unit 120 can be provided for securing the top ends of the inclined runners. In this embodiment the upper unit 120 comprises a back plate 121 adapted to be fixed to a vertical part 102 of a structure comprising the upper area 101. In one example the vertical surface 102 can be part of a floor joist and the back plate 121 can be bolted or screwed to the floor joist. The upper unit 120 is provided with a platform bar 122 adapted to support a rearmost part of a tread portion of a top step. Thus in use the top unit 121 is located so that the distance between the top surface of the platform bar 122 and the horizontally extending upper area 101 is equal to the distance between the tread portions of each pair of adjacent steps, so that the vertical extent provided thereby comprises the vertical distance between the top step and the upper area 101 and is equal in height to the distance between the tread portions of each pair of adjacent steps.

The upper unit 120 further comprises side panels 124 and first and second runner fixing brackets 123 for fixing the inclined runners to the upper unit. The inclined runners are, in use, located between fixing bracket 123 and a side panel 124, in a manner not dissimilar to the manner in which they are located in the base unit 110.

The top and bottom ends of the runners may be cut or bevelled to contour to and closely abut the back plate 121 and bottom plate 111 respectively. This can be achieved by bevelling at angles determined by running a level line between the base unit and upper unit and/or by simple measurement and trignometry.

Fig. 11 is a schematic cross sectional representation of a step 10 as described above. The purpose of this representation is to assist in illustrating (in Figs. 13 to 15) construction of a set of steps. It will be appreciated that Figs. 11 to 15 are not to scale, and in particular the thickness of the tread portions and riser portions are greatly exaggerated. Fig. 12 illustrates schematically in cross section a front riser portion 135 and tread portion 132 and one lateral side panel 133 of a top step 130. It will be appreciated that the top step 130 is similar in structure to the step 10 (which may be regarded as an intermediate step) but that it is not provided with a rear riser portion, height adjustment mechanism or fixing brackets since it is not required to support a further higher step or to be fixed to an inclined runner at its rear (since it is instead fixed to a support, such as the platform bar 122 of the upper unit) .

Construction of a set of steps will now be described further with reference to Figs. 13 to 15. After a user has determined the horizontal length to be covered by the set of steps and attached the base unit 110 so that the front riser panel 12 is spaced apart from a vertical surface 102 to which the upper unit is to be mounted by horizontal distance corresponding to the horizontal length L and further attached the upper unit 120 to a vertical surface 102 of the upper area 101 so that a platform bar 122 is spaced vertically from the upper area 101 (by a height corresponding to the height of each step) as described, the inclined runners 140 can be cut to length and installed. In order to do this the distance between the bottom of the front riser panel 112 and the rear of the underside of the platform bar 122 is measured and a runner is cut to length so that an upper surface thereof fits within the ends of the inclined runner and can be shaped or bevelled so that a lower end is substantially flush with and rests upon the bottom plate 110 and an upper end is substantially in engagement with a front surface of the back panel. It will be appreciated that first and second inclined runners 140 are provided at either side of the staircase being constructed.

A user then sets the height adjustment mechanism of the base unit 110 and of each step 10 to the height determined as the desired vertical distance between the tread portions of adjacent steps and ensures that each height adjustment mechanism is appropriately locked. Of course the adjustment of the height adjustment mechanisms may be performed prior to installation of the base unit 110 and upper unit 120 or at any other convenient time. The user then brings a first, lowermost, step 150 into contact with the base unit 110. The lowermost step 150 is almost identical to each of the intermediate steps (as described above with reference to step 10) except that the tread portion side panels 52 are truncated so that they do not extend below the level of the front riser panel, since this could cause them to snag upon the surface of the ground or lower area 103 and prevent effective installation. In all other respects the lowermost step 150 is identical to step 10 described above and the same reference numerals are used to designate corresponding parts . The lowermost step 150 is brought into engagement with the base unit 110 so that the front riser panel is in front of and in contact with the front riser panel 112 of the base unit 110. The tread portion 20 of the lowermost step 150 is supported on the height adjustment mechanism 116 of the base unit 110. The rear part of the tread portion 20 of the lowermost step is supported on an upper surface of each of inclined runners 140 (by contact of support portions corresponding to support portions 22A described above) with the inclined runners 140. The inclined runners 140 are thus located between support brackets 60 and rear side parts (not shown but corresponding to rear side parts 42) of the lowermost step 140. If the height adjustment mechanism 116 of the base unit 110 is adjusted correctly the tread portion 20 of the lowermost step 150 will be horizontal. When the lowermost step 150 is determined to be correctly positioned (as illustrated in Fig. 14) the front riser panel 50 of the lowermost step 150 is secured to the front riser panel 112 of the base unit 110, the tread portion side panels rear side parts and runner fixing brackets 60 of the lowermost step are attached to the inclined runners by suitably positioned fasteners such as screws or by any other suitable alternative means. The lowermost step 150 is thus effectively located in position.

Subsequent steps, such as steps 10, are then added sequentially from lower to higher, the front portion of each step being supported by the height adjustment mechanism of the next lower step and the rear portion of the tread member of each step being supported upon the inclined runners. After positioning of each step that step is secured to the adjacent lower step and to the inclined runners 140.

Finally the top step 130 is added (as illustrated in Pig. 15) and the rear part of the tread portion thereof is screwed to the platform bar 122 effectively completing the construction of the staircase (although of course ballustrading or carpeting can be added subsequently as can facing panels such as timber veneer to improve the appearance of the finished staircase) .

It will be appreciated that the front part of each step is slightly wider than the rear of each step and thus that each step is effectively placed over the rear riser portion of the previously added lower step so that the rear riser side portions 41 of each step are provided between, and in contact with, the tread portion side panels 52 of the next. Such an arrangement is illustrated schematically in Figs. 16 and 17 in which it can be seen that rear riser side portions 41A of a lower step 1OA are effectively between the rear portion side panels 52B of a next higher step 1OB. Similarly rear riser side portions 4IB of the higher step 1OB are within tread portion side panels 52C of a still higher step 1OC. A similar arrangement is shown without repeated annotations in Fig. 17, which also illustrates how a truncated portion 156 of a tread portion side panel 152 of the bottom step 150 avoids undesirable engagement with the ground. An inclined dotted line 170 illustrates the position of an upper surface of a support runner and it will be appreciated that the different vertical spacings of the steps between Figs. 16 and 17 allow the tread portions to be horizontal notwithstanding the slightly different angles of inclination of the support runners as illustrated by lines 170. Further it will be appreciated that the inclined lower edges 55 of the steps form a generally continuous lower profile which is easy to dress for added attractiveness or which can be retained as is.

Finally Fig. 18 illustrates in partial cross- section a constructed staircase having six steps and shows in a more realistic fashion than previous drawings bolts 260,261 which are used to fix the base unit 110 to a concrete floor 203 and bolts 270,271 which are used to fix an upper unit 120 to a timber floor joist 202. Further Fig. 18 illustrates schematically a carpet 280 laid upon the stairs and sound deadening 290, for example in the form of bitumen of some other suitable sound deafening material applied to the underside of the stairs .

It will be appreciated that the described embodiments can be constructed in various ways and with various numbers of fixing apertures and of various sizes. In one embodiment the base plate is formed of 3mm thick sheet steel is 900mm wide and 200mm in depth with a front riser portion of 150mm. Similarly in one example embodiment an intermediate step (such as step 10) is provided with five holes in the lower riser portion to assist attachment by use of screws to an upper riser portion of a lower step is formed from 2mm thick sheet steel, has lower and upper riser portions which are 150mm high and has side panels with height of 220mm at the front and 50mm at the rear. Again in an example embodiment a top unit has six apertures to receive screw for screwing it into a floor joist (for example with tek wood screws) and eight holes to facilitate attachment to the runners . Further in such an example embodiment the runners are formed of box section 4mm thick high tensile steel and have a width of 50mm and a height (in cross-section of 75mm) . It will be appreciated that the embodiments described above allow straight forward construction of a set of stairs across a range of heights while allowing a uniform stair height for the stairs in any set. Furthermore, the stairs are prefabricated and this may- provide a substantial environmental benefit.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as

"comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.