WO2014032091A1

WO2014032091A1 - A stair case

Info

Publication number: WO2014032091A1
Application number: PCT/AU2013/000955
Authority: WO
Inventors: Darren BRINK
Original assignee: Quicksmart Stairs International Pty Ltd
Priority date: 2012-08-28
Filing date: 2013-08-28
Publication date: 2014-03-06

Abstract

There is disclosed a stair case (10) that has one or more stringers (12), treads (14) that are supported on the stringers, and risers (16) First connectors (18) are secured to an under surface the tread (14), and second connectors (20) are secured to the risers (16). The first and second connectors (18, 20) are interconnected to secure each tread (14) to one of the risers (16).

Description

A Stair Case

Field of the invention

The present invention relates to a stair case, and to a method of constructing a stair case.

Background

Traditional stair cases are constructed by firstly installing stringers, and then installing treads and risers alternately along the length of the stair case. The stringers have wedge shaped rebates for each tread and each riser. Once each tread/riser has been located in the stringers, wedges are driven into the rebates to hold the respective tread or riser in position. Furthermore, glue is used to secure the treads, risers and wedges to the stringers.

It is also common to glue a block between the stringers, and beneath each tread and behind the riser immediately below that tread. This block helps to minimize relative movement between the tread and riser, which is a cause of "squeaking" when a person steps on the tread.

For convenience, it is common to start installation of a treads and risers of the stair case with top most tread, and work down to the lower most riser, with the installer positioned beneath the stair case. This gives rise to several problems. Often the installer is initially working above their head height. When finishing the installation, the installer is working in a confined space at ground level. In addition, the installer is required to use large quantities of glue, which can be messy and unpleasant to work with.

There is a need to address the above, and/or at least provide a useful alternative.

Summary of the invention

The present invention provides a stair case comprising:

one or more stringers;

treads that are supported on the stringers;

risers;

first connectors, each tread having at least one of the first connectors secured to an under surface that tread; and

second connectors that are each secured to a respective one of the risers, wherein the first and second connectors are interconnected to secure each tread to one of the risers.

In some embodiments, the first and second connectors are interconnected to secure each tread to the riser immediately below that tread in the stair case.

Preferably, each of the second connectors is secured to an upper edge of the respective riser. In certain embodiments, each stringer has:

, a plurality of tread supporting faces,

a plurality of riser abutment faces, and

a plurality of undercut sections in the regions where the bottom edge of riser abutment face meets a tread supporting face,

wherein each tread has a nose and a toe, and wherein each undercut section receives the toe of one of the treads.

Preferably, the undercut section is shaped such that the tread can be inclined relative to the tread supporting face, the toe of the inclined tread can be inserted into the undercut section, and the tread rotated or pivoted within the undercut section to bring the tread into contact with the tread supporting face.

In some embodiments, each undercut section has an upper edge that is convex, such that the toe of a tread can be inserted into the undercut section and pivoted to bring the tread in contact with the tread supporting face.

In some alternative embodiments, the tread supporting face within each undercut section includes an arcuate surface, which enables the toe of a tread can be inserted into the undercut section and rotated on the arcuate surface to bring the tread in contact with the tread supporting face.

In certain embodiments, each tread supporting face has a rib that extends transversely to the longitudinal direction of the stringer, and each tread has a groove that receives the rib.

Preferably, the first and second connectors interconnect with a snap-type connection. More preferably, the first and second connectors are a male and female pair. Preferably, the first and second connectors are shaped to resist disconnection. Preferably, one of the first and second connectors has an abutment shoulder to limit the relative movement of the first and second connectors in a direction parallel to the direction of interconnection.

In some preferred embodiments, each of the first and second connectors is an extruded section.

In some embodiments, at least some of the treads have a channel formed on the under surface within which one of the first connectors is secured. In some further embodiments, each of the risers has a channel formed on the upper edge within which one of the second connectors is secured.

The stair case may further comprise:

a plurality of third connectors, and at least a subset of the treads having at least one of the third connectors secured to an upper surface; and

a plurality of fourth connectors, and at least a subset of the risers having at least one of the fourth connectors secured to a lower edge,

wherein the third and fourth connectors are interconnected to secure each riser in the subset of risers to the tread immediately below that riser in the stair case. Preferably, the third and fourth connectors interconnect with a snap-type connection. More preferably, the third and fourth connectors are a male-female pair. Preferably, the third and fourth connectors are shaped to resist disconnection. Preferably, one of the third and fourth connectors has an abutment shoulder to limit the relative movement of the third and fourth connectors in a direction parallel to the direction of interconnection.

In some preferred embodiments, each of the third and fourth connectors is an extruded section. In some embodiments, each of the treads has a channel formed on the upper surface within which one of the third connectors is secured. In some further embodiments, at least some of the risers have a channel formed on the lower edge within which one of the fourth connectors is secured. Preferably, the first and third connectors are substantially identical, and the second and fourth connectors are substantially identical.

In some embodiments, the upper ends of the stringers terminate with a tread supporting surface. ln one embodiment, the stair case includes one or more brackets that connect the bottom most'riser to lower ends of the stringers. In at least some of these embodiments, the stair case further comprises a top tread support that provides vertical support to the toe of the top most tread in the stair case. ¹

Preferably, the top tread support has at least one fifth connector, and the upper most tread has at least one sixth connector provided on its under surface, wherein the fifth and sixth connectors are interconnected to secure the toe of the upper most tread to the top tread support.

Preferably, the top tread support extends between, and is secured to, the stringers. Alternatively or additionally, the top tread support is secured to a supporting structure at the top of the stair case.

Preferably, the first and fifth connectors are substantially identical, and the second and sixth connectors are substantially identical.

The stair case may further comprise a top most riser that extends above the stringers, the top most riser extending above the top most tread in the stair case. The top most riser can be secured to a supporting structure. In some embodiments, the top most riser has one or more rebates, and the stringers each have a tongue that is received in a respective one of the rebates.

The stair case may further comprise a bottom riser support that is attached to any one or more of: the lower level, the structure supporting the lower level, or the or each stringer. The bottom riser support also includes a third connector to which the lower most riser is connected. The lower most riser can be shaped to hide the bottom riser support.

In some embodiments, the stair case includes a fascia strip that is secured to the top most riser, and has at least a portion that overhangs an outer surface of the top most riser. The overhanging portion can have a shape to match the shape of the nose of each tread. In one example, the overhanging portion can have a bull-nose shape. The fascia strip can be secured to the outer surface of the top most riser. Alternatively, the fascia strip can be secured to the upper edge of the top most riser. In at least some embodiments, the stair case further comprises a pair of stringer covers that has a lower edge with a profile that matches at least some of the top surface of the treads and the outer surface of at least some of the risers. Preferably, each stringer cover is located adjacent a lateral edge of the stair case.

The present invention also provides a method of constructing a stair case, the method involving:

providing one or more stringers;

attaching the or each stringer to one or more supporting structures;

providing treads that each have a first connector secured to an under surface of that tread;

providing risers that each have a second connector secured thereto;

alternately installing the risers and the treads,

whereby installing the treads interconnects the first and second connectors and secures each tread to one of the risers.

The method may further involve interconnecting the first and second connectors to secure each tread to the riser immediately below that tread in the stair case. In certain embodiments, each stringer has a plurality of tread supporting faces, a plurality of riser abutment faces, and a plurality of undercut sections in the regions where the bottom edge of riser abutment face meets a tread supporting face; and

each tread has a nose and a toe,

wherein installing each tread further involves inserting the toe of the respective tread into one of undercut sections.

Installing each tread can further involve inclining the tread relative to the tread supporting face, whereby the toe is inserted into the undercut section in the inclined position.

Each undercut section can have an upper edge that is curved, and the method can further involve.

inserting the toe of a tread into the undercut section, and

pivoting the respective tread about the toe to bring the tread in contact with the tread supporting face.

In embodiments in which the stair case further comprises:

a plurality of third connectors, and a subset of the treads having at least one of the third connectors secured to an upper surface; and a plurality of fourth connectors, and a subset of the risers having at least one of the fourth connectors secured to a lower edge,

the method may further involve interconnecting the third and fourth connectors to secure the each riser in the subset of risers to the tread immediately below that riser in the stair case.

In embodiments in which the stair case further comprises a pair of stringer covers that has lower edge with a profile that matches at least some of the top surface of the treads and the outer surface of at least some of the risers, the method can further involve installing the stringer covers over the installed treads and risers. In some embodiments, the method further involves securing the stringer covers to any one or more of: the stringers, the treads, the risers, the first supporting structure, and the second supporting structure. The method may involve temporarily stowing the stringer covers beneath installed treads and risers, and then installing the stringer covers.

The present invention also provides a stair case comprising:

one or more stringers;

treads that are supported on the stringers;

second connectors that are each secured to a respective one of the stringers, wherein the first and second connectors are interconnected to secure each of the treads to the stringers.

In some embodiments, the stair case can further comprise risers. Thus, in these embodiments, the stair case forms a closed stair. Preferably, each riser is restrained in place by the interconnection of the treads to the stringers.

providing one or more stringers;

attaching the stringers to one or more supporting structures;

providing second connectors that are each secured to a respective one of the stringers;

installing the treads, whereby installing the treads interconnects the first and second connectors and secures each tread to the stringers.

Attaching the stringers may involve attaching an upper end of the or each stringer to a first supporting structure. Alternatively or additionally, attaching the stringers may involve attaching the lower end of the or each stringer to a second supporting structure.

Preferably, interconnecting the first and second connectors involves securing the risers relative to the treads and stringers.

The method can further involve providing risers, and installing the risers alternately with the treads.

The present invention also provides a stair case comprising:

one or more stringers;

a plurality of tread and riser units that are supported on the stringers;

first connectors that are each secured to an under surface a respective tread and riser unit; and

second connectors that are each secured to an upper surface of a respective tread and riser unit,

wherein the first and second connectors are interconnected to secure the tread and riser units to one another.

providing one or more stringers;

installing the stringers such that an upper end of the or each stringer is attached to a first supporting structure, and the lower end of the or each stringer is attached to a second supporting structure;

providing tread and riser units that each have a first connector secured to an under surface of the respective unit, and a second connector secured to an upper surface of the respective unit;

sequentially installing the tread and riser units,

whereby installing the tread and risers interconnects the first and second connectors and secures the units to one another.

The present invention also provides a tool for locating an upper end of a stair case stringer relative to a datum surface, the tool comprising:

a post; a datum guide that is connected to the post, and projects laterally from the post; and

a stringer support that is connected to the post,

whereby, in use the datum guide rests on the datum surface, and the upper end of the stringer is supported on the stringer support below the datum surface, and the stringer is pivotable on the stringer support.

The datum guide can be slidable along the post, and restrained in a desired place by a releasable lock. Alternatively or additionally, the stringer support is slidable along the post, and restrained in a desired place by a releasable lock.

The tool can include a first graduated scale, such that the position of the stringer support along the post can be measured. The tool can include a second graduated scale, such that the position of the datum guide along the post can be measured relative to a first pre-defined position.

In certain embodiments, the stringer support includes one or more seats, and at least a locating portion of the upper end of the stringer is shaped to locate in one of the seats. Preferably, the seats and the locating portion have a complementary shape, which enables the locating portion to be supported in one of the seats and rotated within that seat. Preferably, one of the seats and locating portion is concave, and the other of the locating portion and seats is convex.

The datum guide can include one or more clearance holes for use in fixing the tool to a structure.

Preferably, the stringer support has two seats that are each on a respective side of the post, such a stringer can be supported on either side of the post. The present invention also provides a method of locating an upper end of a stair case stringer relative to a datum surface, the stringer including a locating portion at the upper end, and the method involving.

providing a tool as previously described;

locating the datum guide on the datum surface; and

supporting the locating portion of the stringer in the stringer support,

whereby the tool is removable once the stringer has been fixed in place.

Brief description of the drawings In order that the invention may be more easily understood, embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 : is a perspective view of a stair case according to a first embodiment of the present invention;

Figure 2: is a side elevation view of the stair case of Figure 1 ;

Figure 3: is an enlarged view of region A in Figure 2;

Figure 4: is a side view of a stringer of the stair case of Figure 1 ;

Figure 5: is a side view of a tread and risers of the stair case of Figure 1 ;

Figure 6: is a cross section view of first and second connectors of the stair case of Figure 1 ;

Figure 7: is a side view of the top tread and top tread support of the stair case of

Figure 1 ;

Figure 8: is a side view of a stringer cover of the stair case of Figure 1 ;

Figure 9: is a flow chart of a method of constructing a stair case in accordance with a second embodiment of the present invention;

Figure 10: is a side view of a stair case according to a third embodiment of the present invention;

Figure 11 : is an enlarged view of region B in Figure 10;

Figure 12: is a side elevation of a stair case in accordance with a fourth embodiment of the present invention;

Figure 13: is an upper left perspective view of a tool in accordance with a fifth embodiment of the present invention;

Figure 14: is a left side view of the tool of Figure 13;

Figure 15: is a right side view of the tool of Figure 13;

Figure 16: is a right side view of the tool of Figure 13, with a stringer of the stair case of Figure 12;

Figure 17: is an enlarged view of region A in Figure 16;

Figure 18: is a side elevation of a stair case in accordance with a sixth embodiment of the present invention;

Figure 19: is a perspective view of a stair case in accordance with a seventh embodiment of the present invention;

Figure 20: is a perspective view of the winder section of the stair case of Figure

19;

Figure 21 : is a perspective view of the stringer segments of the stair case of

Figure 19; and

Figure 22: is a side elevation of a stair case in accordance with an eighth embodiment of the present invention. Detailed description

Figures 1 to 8 show a stair case 10 according to a first embodiment of the present invention. In this embodiment, the stair case 10 has a pair of spaced apart stringers 12, of which only one is shown in the Figures. Treads 14 of the stair case 10 are supported on the stringers 12. In this embodiment, the stair case is a "closed" stair case in that the stair case 10 includes risers 16 below each tread 14.

The stair case 10 has first connectors 18 and second connectors 20. Each tread 14 has at least one of the first connectors 18 secured to an under surface that tread 1 . In this embodiment, each of the second connectors 20 is secured to the risers 16, as shown most clearly in Figure 3.

In the assembled stair case 10, the first and second connectors 18, 20 are interconnected to secure each tread 14 in place relative to the stringers 12. Securing the treads using the connectors^" has the distinct advantage that the stair case can, in some embodiments, be assembled without requiring the use of glue.

As shown in Figures 1 and 2, in this embodiment the stair case 10 extends from a lower level L, which is a ground or floor surface beneath the feet of the person shown in Figure 1 , and an upper level U. The upper level U is a floor surface supported by a supporting structure S, such as the frame of a house. In a domestic dwelling each of the lower and upper levels L, U may be a floor surface, or a landing positioned between multiple flights of stairs.

As shown most clearly in Figure 3, each of the second connectors 20 is secured to an upper edge of the respective riser 16. Thus, each riser 16 is secured to the tread 14 that is immediately above that riser 16 in the stair case 10, by the interconnection of the first and second connectors 18, 20.

Each tread 14 has a nose 15a, and a toe 15b that is at the opposing edge to the nose 15a. As shown in Figure 4, each stringer 12 has a plurality of tread supporting faces 22 that each support a tread 14, and a plurality of riser abutment faces 24 that are each in contact with a riser 16. In each region where the bottom edge of riser abutment face 24 meets a tread supporting face 22 the stringer has an undercut section 26. The toe 15b of each tread 14 is received in one of the undercut sections 26. In this way, the toe 15b of each tread 14 is vertically constrained by the stringers 12. In this embodiment, each undercut section 26 has an upper edge that is convex. Accordingly, during assembly the toe 15b of a tread 14 can be inserted into the undercut section 26, and then pivoted to bring the tread 1 in contact with the tread supporting face 22. Further, during this pivoting action, the first and second connectors 18, 20 are brought into engagement, which secures the respective tread 14 to the riser 16 that is immediately below that tread in the stair case 10.

As is also shown in Figure 4, each tread supporting face 22 has a rib 28 with a constant cross section in a direction transverse to the longitudinal direction of the stringer 12, and also generally transversely to the longitudinal direction of the tread support face 22. Furthermore, each tread 14 has a groove 30 that receives the rib 28, the groove 30 being formed in the under side of the tread 14. As shown in Figure 5, the groove 30 is shaped to facilitate location of the rib 28 within the groove 30, but to minimize movement of the tread 14 relative to the stringers 12. As will be appreciated, the ribs 28 and grooves 30 co-operate to further secure the treads 14 relative to the stringers 12.

In this embodiment, each of the first and second connectors 18, 20 is an extruded section that extends along the width of the stair case 10. Figure 6 shows a first and second connector 18, 20 spaced apart. Each of the connectors is shaped to co-operate with the other so that in connecting one to the other, such that they form a male and female pair.

The first and second connectors 18, 20 interconnect with a snap-type connection. In this embodiment, the first connector 18 has a pair of spaced apart first ribs 32. The second connector 20 also has a pair of spaced apart second ribs 34 that have a narrower spacing so that the second ribs 34 are received between the first ribs 32.

Each first rib 32 of the first connector 18 has a longitudinal lip 36. The distal edge of each second rib 34 of the second connector 20 forms a bead 38. During insertion of the second ribs 34 between the first ribs 32, the beads 38 bear against the lips 36, which deflects both pairs of ribs 32, 34. With further insertion of the second ribs 34 into the first ribs 32, the beads 38 pass over the lips 36, which "snaps" the first and second connectors 18, 20 together. The lips 36 are shaped to resist disconnection of the first and second connectors 18, 20. The second connector 20 has an abutment shoulder 40 on each second rib 34 that limit further insertion of second connector into the first connector by the distal end of the first ribs 32 abutting the shoulders 40. Within the stair case 10, this arrangement limits relative movement of the first and second connectors 18, 20 in a direction that is generally parallel to the direction of interconnection. Thus, relative movement of the treads 14 and risers 16 is limited in response to vertical loads on the treads 14. The interconnection between the connectors 18, 20 minimizes noise (such as squeaks) caused in stair cases by contacting components moving relative to one another.

Each tread 14 has a channel 42 formed on the under surface within which one of the first connectors 18 is secured. Further, each riser 16 has a channel 44 formed on its upper edge within which one of the second connectors 20 is secured. The first and second connectors 18, 20 can be secured in their respective channels 42, 44 by adhesives, fasteners, and/or by a mechanical interference. The stair case 10 further has third connectors 46 that are each secured to the upper surface of treads 14 in at least a subset of the risers. In this particular embodiment, the subset of treads 14 include all the treads except the top most tread 14a in the stair case 10, which is the tread that is level with the upper level U. The stair case 10 also has fourth connectors 48 that are each secured to the lower edge of risers 16 in at least a subset of the risers. The subset of risers 16 includes all the risers except the lowermost riser in the stair case 10.

The third and fourth connectors 46, 48 are interconnected to secure the each riser 16 in the subset of risers to the tread 14 immediately below that riser in the stair case 10. The third and fourth connectors 46, 48 facilitate securing the lower edge of the risers 26 in the subset of risers relative to the tread 14 immediately below these risers.

In this embodiment, the third connectors 46 have an identical profile to the first connectors 18, and are secured to the treads 14 in the manner previously described. Further, the fourth connectors 48 also have an identical profile to the second connectors 20, and are secured to the risers 16 in the manner previously described. Accordingly, the third and fourth connectors 46, 48 interconnect in the same manner as the first and second connectors 18, 20. In the embodiment illustrated in Figures 1 to 7, the upper ends of the stringers 12 terminate with a tread supporting surface 22, and the stair case further comprises a top tread support 50 that provides vertical support to the toe 52 of the top most tread 14a in the stair case 10. The top tread support 50 and the top most tread 14a are shown in Figure 7.

As shown in Figure 7, the upper most tread 14a has at least one fifth connector 54 provided on its under surface, and the top tread support has at least one sixth connector 56. The fifth and sixth connectors 54, 56 are interconnected to secure the toe 52 of the upper most tread 14a to the top tread support 50. The top tread support 50 extends between the stringers 12, and can be secured to the stringers 12 and/or the supporting structure S at the top of the stair case. In this embodiment, the fifth connector 54 has an identical profile to the first connectors 18, and is secured to the under surface of the tread 14a in the manner previously described. Further, the sixth connector 56 also has an identical profile to the second connectors 20, and is secured to the top tread support 50 in the manner previously described with reference to the risers 16 and second connectors 20. Accordingly, the fifth and sixth connectors 54, 56 interconnect in the same manner as the first and second connectors 18, 20.

It will be appreciated that in some alternative embodiments, the first and second connectors may be in the form of a mating pin and blind hole, respectively. In some further alternative embodiments, the first and second connectors may be in the form of a lengths of complementary extruded sections that extend parallel to the going of the stair case. Alternatively or additionally, the complementary extruded sections may have a length that is less than the width/tread depth of the stair case. Similarly, with regard to the third and fourth connectors, and/or the fifth and sixth connectors.

In this particular embodiment, the first, third, and fifth connectors 18, 46, 54 are substantially identical to one another. Furthermore, the second, fourth and sixth connectors 20, 48, 56 are substantially identical to one another. The stair case 10 also includes a pair of stringer covers 58, one of which is shown in Figure 8. Each stringer cover 58 has a lower edge 60 with a profile that matches at least some of the top surface of the treads 14 and the outer surface of at least some of the risers 16. As shown in Figure 1 , each stringer cover 58 is located adjacent a lateral . edge of the stair case 10.

The stringer covers 58 have the advantage of hiding the intersecting top and outer surfaces of the treads 14 and risers 16 adjacent the lateral edges of the stair case 10. Furthermore, the stringer covers 58 give the appearance of a stringer of a traditionally constructed stair case.

Figure 9 shows a flow chart for a method 100 of constructing a stair case in accordance with a second embodiment. The method 100 involves:

• providing a pair of stringers, at step 102

• installing the stringers, at step 104; • providing a plurality of treads that each have a first connector secured to an under surface of that tread, at step 106;

• providing a plurality of risers, at step 108;

• providing a plurality of second connectors to one of: the stringers, or the risers, at step 1 10; and

• alternately installing the risers and the treads, at step 1 12.

Installing the treads (at step 1 12) interconnects the first and second connectors, which secures each tread in place relative to the stringers.

The second connectors can be secured to the stringers or risers, such that step 1 10 occurs prior to, or concurrently with, either step 102 or step 108.

In step 104, the stringers are installed such that an upper end of each stringer is attached to a first supporting structure, and the lower end of each stringer is attached to a second supporting structure. This may involve fastening the stringers to the supporting structures.

Figures 10 and 11 show a stair case 210 according to a third embodiment of the present invention. The stair case 210 is substantially similar to the stair case 10 of Figures 1 to 8. In Figures 10 and 11 , the features of the stair case 210 that are substantially similar to those of the stair case 10 have the same reference numeral with the prefix "2". The principal differences between the stair case 10 and the stair case 210 reside in the arrangement at the top and bottom of the respective stair cases.

At the top of the stair case 210, the upper ends of the stringers 212 terminate with a tread supporting surface. A top most riser 216a extends above the stringers 212. Further, the top most riser 216a extends both above and below the top most tread 214a.

In this embodiment, the top most riser 216a is secured to the supporting structure S, which supports the upper level U. The top most riser 216a has a rebate formed in each lateral edge. Each stringer 212 has a tongue 262 that is located in a respective rebate. Thus, the top end of each stringer 212 is supported by the top most riser 216a.

As shown in Figure 1 1 , the stair case 210 includes a fascia strip 264 that is secured to the top most riser 216a. In this embodiment, the fascia strip overhangs the outer (upright) surface of the top most riser 216a. The overhanging portion can have a shape to match the nose of the treads 214, which in this embodiment is of bull-nose shape. As is also shown in Figure 1 1 , the fascia strip 264 is secured to the outer (upright) surface of the top most riser 216a.

At the bottom of the stair case 210, a bottom riser support 266 is provided, and can be secured to the floor at the lower level L, or the structure supporting the floor. The bottom riser support 266 includes a pair of brackets 268, and a stringer 212 is attached to each bracket. The bottom riser support 266 also includes a third connector 246 to which the lower most riser 216b is connected. In this embodiment, the lower most riser 216b is shaped to hide the bottom riser support 266 once the stair case 210 is assembled.

Figure 12 shows a stair case 310 according to a fourth embodiment of the present invention. The stair case 310 is substantially similar to the stair case 10 of Figures 1 to 8. In Figure 12, the features of the stair case 310 that are substantially similar to those of the stair case 10 have the same reference numeral with the prefix "3".

The stair case 310 has undercut sections 326 formed in the stringers 312 in each region where the bottom edge of one of the riser abutment faces 324 meets one of the tread supporting faces 322. Each tread supporting face 322, within its respective undercut section 326 includes an arcuate surface 370. During installation, the toe of a tread 314 is to be inserted into the undercut section 326 and pivoted on the arcuate surface 326 to bring the tread 314 in contact with the tread supporting face 322. Each of the ribs 328 on the stringers 312 has a trapezoidal cross section in a direction perpendicular to the longitudinal direction of the respective stringer 312. The groove 330 in each tread 314 has a complimentary trapezoidal cross section. In the installed stair case 310, each tread 314 is placed under flexion by the rib 328 on the respective tread supporting face 322 opposing forces applied by the stringer 312 within the undercut section 326 and the connection to the riser 316 immediately below the respective tread 314. This can reduce the likelihood of relative movement between the treads 314 and stringers 312, and thus can reduce the likelihood of the stair case 310.

The upper end of each stringer 312 includes a circular lobe 372 that facilitates locating the stringer 312 relative to other building/supporting structures and/or additional stringer members of the stair case 310 during installation.

In this embodiment, each stringer is mounted against, and fixed to, building structures, such as stud walls, that are on either side of the stair case 310. Each lateral edge of the bottom most riser 316b is attached to the internal sides of the stringers 312 by a bracket (not shown). During installation, the bottom most riser 316b can be installed prior to locating the stringers 312 relative to the supporting structures. The brackets secure the stringers 312 at 90° to the bottom most riser 316b. The connection of the lower end of the stringers via the bottom most riser 316b facilitates initial adjustments of the stringers 312, including levelling of the tread supporting faces such that the treads 314 will be level in the assembled stair case 310, and also such that the stringers 312, treads 314, and risers 316 are square in the assembled stair case 310.

Figures 13 to 15 show a tool 400 for locating an upper end of a stair case stringer relative to a datum surface. The datum surface can be an underfloor structure at the upper level U of building. The tool 400 has a post 402, a datum guide 404, and a stringer support 406. The datum guide 404 and stringer support 406 are each connected to the post 402. The datum guide 404 projects laterally from the post 402.

Figures 16 and 17 show the tool 400 in use with a stringer 312 of Figure 12. As shown in Figure 16, the datum guide 404 rests on the datum surface D. The upper end of the stringer 312 is supported on the stringer support 406 below the datum surface. As indicated by arrow R in Figure 17, the stringer 312 is rotatable on the stringer support 406.

The datum guide 404 can slide along the post 402, and restrained in a desired place by a releasable lock, which in this embodiment is in the form of a screw lock 408. In addition, the stringer support 406 can also slide along the post 402, and restrained in a desired place by a releasable lock, which in this embodiment is in the form of a screw lock 410.

The tool 400 includes a first graduated scale 412, which can be used to measure the position of the stringer support 406 along the post 402. When an operator is installing a stair case, the position of the stringer support 406 - and also that of the upper end of the stringer - can be measured along the post 402 using the first graduated scale 412, and set using the screw lock 410. The first graduated scale 412 represents the height of the uppermost riser within the stair case.

The tool 400 also includes a second graduated scale 414, which can be used to measure the position of the datum guide 404 along the post 402. Using the screw lock 408, the datum guide 404 can be set in a desired position along the post 402. In use, an operator can ascertain the final floor height of the Upper level above the datum surface, and the final floor height used to set the datum guide 404 relative to the post 402.

In this embodiment, the stringer support 406 includes two seats 416 that each have a shape that complements the shape of the circular lobe 372 on the upper end of the stringer 312 illustrated in Figure 12. The lobe 372 can be positioned in one of the seats 416 to be supported within that seat 416, and rotated as indicated in Figure 1 In this embodiment, the seats 416 are concave, and the lobe 372 is convex, as shown in Figures 13 to 7. The stringer support 406 has the seats 416 on opposing sides of the post 402, such a stringer can be supported on either side of the post 402. In other words, the tool 400 can be used to support a stringer on either the left or right side of a stair case.

The datum guide 404 includes clearance holes 418 for use in fixing the tool 400 to a structure on the datum surface D. To this end, a screw, nail or the like can be passed through the clearance holes 418 into the structure.

In some alternative embodiments of the tool, the datum guide can include a hinge or pivoting joint to allow at least a portion of the datum guide to be folded for stowing, such that the datum guide is generally parallel with the post.

Figure 18 shows a stair case 510 according to a sixth embodiment of the present invention. The stair case 510 is substantially similar to the stair case 10 of Figures 1 to 8. In Figure 18, the features of the stair case 510 that are substantially similar to those of the stair case 10 have the same reference numeral with the prefix "5".

In contrast to the stair case 10, the stair case 510 is arranged with the bottom edge of the risers 516 (excluding the bottom most riser 516b) being received within a recess 580 that is formed at the base of the riser abutment faces 524. The bottom of each recess 580 is below the level of the adjacent tread supporting surface 522. In this way, the bottom edge of the risers 516 are restrained relative to the stringers 512.

Furthermore, each riser abutment face 524 includes a rib 582, and each riser 516 includes a groove 584. The ribs 582 and grooves 584 have the same shape and function as the ribs 528 and grooves 530.

In this embodiment, the third connectors 546 are each secured to the toe of the in the treads 514. The fourth connectors 548 are each secured to a front face of at least a subset of the risers 516. The installation sequence of the stair case 510 requires that two sequential risers 516 are positioned on the stringers 512, and then the tread 514 to which both risers 516 are connected is installed and connected to the respective risers 516.

Figures 19 to 21 show a stair case 610 according to a seventh embodiment. The stair case 610 is substantially similar to the stair case 10 of Figures 1 to 8. In Figure 19, the features of the stair case 610 that are substantially similar to those of the stair case 10 have the same reference numeral with the prefix "6".

The stair case 610 includes two straight flights of stairs 610a, 610b, and a winder section 690, which includes six winder stringer segments 692a to 692f that are each to be attached to a building structure. Winder treads 694 of irregular shape enable the winder section to turn about a central post (also not shown). Three of the winder stringer segments 692d to 692f are attached to the central post, and the remaining winder stringer segments 692a to 692c are attached to the building structure on the outer side of the winder section 690. The winder section 690 also includes risers 696, with the winder stringers 692, treads 694 and risers 696 being interconnected in the same manner as the stringers 612, treads 614 and risers 616.

The stringers 612 in the straight flights of stairs 610a, 610b have a circular lobe 672 at their upper ends that is of identical shape and function to the lobe 372 of the embodiment shown in Figure 12. The two lowermost winder stringer segments 692a, 692d each include a seat 671 a, 671 b into which a lobe 672 of the stringers 612 in the lower straight flight 610a is to be positioned.

Figure 22 shows a stair case 710 according to an eighth embodiment of the present invention. The stair case 710 is substantially similar to the stair cases 10, 310 of Figures 1 to 8, and 12. In Figure 22, the features of the stair case 710 that are substantially similar to those of the stair case 10 have the same reference numeral with the prefix "7".

In this embodiment, the first and third connectors 718, 746 are integrally formed integrally with the treads 714. Similarly, the second and fourth connectors 720, 748 are formed integrally with the risers 716. In this embodiment, the treads 714 and/or risers 716 can be extruded from aluminium, plastics materials, or composite materials including wood plastics composites. ln one alternative embodiment of a stair case according to the present invention, the second connectors are each secured to a respective one of the stringers. As with the embodiments described in reference to Figures 1 to 8, 10, and 1 1 , the first connectors are each secured to an under surface that tread. In such embodiments, the first and second connectors are interconnected to secure each of the treads to the stringers.

In such an embodiment, each riser is restrained in place by the interconnection of the treads to the stringers. In this way, each riser can "float" between the riser abutment surface of the stringers and the treads immediately above and below the respective riser. Alternatively or additionally, at least one of the first and second connectors can extend through apertures in the risers to further restrain the risers within the stair case.

In one example, the first and second connectors may be arranged to connect in a snap-type style. In another example, the first and second connectors may be arranged to interconnect by a sliding action.

In another alternative embodiment of a stair case according to the present invention, the stair case has one or more stringers, and tread and riser units that are supported on the stringers. First connectors are each secured to an under surface a respective tread and riser unit. Second connectors are each secured to an upper surface of a respective tread and riser unit. In the assembled stair case, the first and second connectors are interconnected to secure the tread and riser units to one another.

In such embodiments, each tread and riser units can be formed of a tread and a riser that are secured to one another, for example by glue or other fasteners. Alternatively, the tread and riser unit can have a- unitary construction. For example, the tread and riser unit may be extruded, or milled.

Accordingly, when the stair case is constructed, the tread and riser units are sequentially installed on the stringer(s).

As will be appreciated, the interconnections between the various connectors in the previously described embodiments has the distinct advantage of allowing an installer to commence installing the risers and treads with the lowermost riser, and continuing to construct the stair case progressively towards the top of the flight of stairs. This has the consequential advantage that the installer can be above the stair case during installation.

In some embodiments, the stair case can be partially constructed, to allow other services/installations to be completed, and the stringer covers installed at a later, more appropriate time. For example, plaster and painting can then be completed with the stair case partially constructed, and the stringer covers installed after the paint has dried. This minimizes damage to the stringers. In this regard, it may be convenient to stow the stringer covers beneath the partially constructed stair case until such time as these are to be installed.

Furthermore, as will be appreciated the nature of the snap connections between the various connectors facilitates rapid construction of the stair case. It is envisaged that the installation of a stair case according to the first embodiment could be completed in two hours or less.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", 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.

Claims

CLAIMS:

1. A stair case comprising:

one or more stringers;

treads that are supported on the stringers;

risers;

2. A stair case according to claim 1 , wherein the first and second connectors are interconnected to secure each tread to the riser immediately below that tread in the stair case.

3. A stair case according to claim 2, wherein each of the second connectors is secured to an upper edge of the respective riser.

4. A stair case according to any one of claims 1 to 3, wherein:

each stringer has a plurality of tread supporting faces, a plurality of riser abutment faces, and a plurality of undercut sections in the regions where the bottom edge of riser abutment face meets a tread supporting face;

each tread has a nose and a toe; and

each undercut section receives the toe of one of the treads.

5. A stair case according to claim 4, wherein the tread supporting face within each undercut section includes an arcuate surface, which enables the toe of a tread can be inserted into the undercut section and rotated on the arcuate surface to bring the tread in contact with the tread supporting face.

6. A stair case according to any one of claims 1 to 5, wherein each tread supporting face has a rib, and each tread has a groove that receives the rib.

7. A stair case according to any one of claims 1 to 6, wherein the first and second connectors interconnect with a snap-type connection.

8. A stair case according to any one of claims 1 to 7, further comprising: a plurality of third connectors, and at least a subset of the treads having at least one of the third connectors secured to an upper surface; and

wherein the third and fourth connectors are interconnected to secure the each riser in the subset of risers to the tread immediately below that riser in the stair case.

9. A stair case according to claim 8, wherein the third and fourth connectors interconnect with a snap-type connection.

10. A stair case according to either claim 8 or 9, wherein the first and third connectors are substantially identical, and the second and fourth connectors are substantially identical.

11. A stair case according to any one of claims 1 to 10, further comprising a top most riser that extends above the top most tread in the stair case.

12. A stair case according to claim 1 1 , wherein the top most riser is secured to a supporting structure.

13. A stair case according to either claim 11 or 12, wherein the top most riser has one or more rebates, and the or each stringer has a tongue that is received in a respective one of the rebates.

14. A stair case according to any one of claims 1 to 13, further comprising a bottom riser support that is attached to any one or more of: the lower level, the structure supporting the lower level, or the or each stringer.

15. A stair case according to any one of claims 1 to 14, further comprising a pair of stringer covers that has a lower edge with a profile that matches at least some of the top surface of the treads and the outer surface of at least some of the risers.

16. A method of constructing a stair case, the method involving:

providing one or more stringers;

attaching the or each stringer to one or more support structures

providing risers that each have a second connector secured thereto,

alternately installing the risers and the treads, whereby installing the treads interconnects the first and second connectors and secures each tread to one of the risers.

17. A method according to claim 16, further involving interconnecting the first and second connectors to secure each tread to the riser immediately below that tread in the - stair case.

18. A method according to either claim 16 or 17, wherein each stringer has a plurality of tread supporting faces, a plurality of riser abutment faces, and a plurality of undercut sections in the regions where the bottom edge of riser abutment face meets a tread supporting face; and each tread has a nose and a toe,

19. A method according to claim 18, wherein the tread supporting face within each undercut section includes an arcuate surface further involving:

inserting the toe of a tread into the undercut section, and

pivoting the respective tread on the arcuate surface to bring the tread in contact with the tread supporting face.

20. A method according to any one of claims 16 to 19, in which the stair case further comprises:

a plurality of third connectors, and a subset of the treads having at least one of the third connectors secured to an upper surface; and

a plurality of fourth connectors, and a subset of the risers having at least one of the fourth connectors secured to a lower edge,

and the method further involves interconnecting the third and fourth connectors to secure the each riser in the subset of risers to the tread immediately below that riser in the stair case.

21. A method according to any one of claims 16 to 20, in which the stair case further comprises a pair of stringer covers that each have a lower edge with a profile that matches at least some of the top surface of the treads and the outer surface of at least some of the risers, and the method further involves installing the stringer covers over the installed treads and risers.

22. A stair case comprising:

one or more stringers;

treads that are supported on the stringers; first connectors, each tread having at least one of the first connectors secured to an under surface that tread; and

23. A stair case comprising:

one or more stringers;

a plurality of tread and riser units that are supported on the stringers;

24. A tool for locating an upper end of a stair case stringer relative to a datum surface, the tool comprising:

a post;

a datum guide that is connected to the post, and projects laterally from the post; and

a stringer support that is connected to the post,

25. A tool according to claim 24, wherein the datum guide is slidable along the post, and the tool further comprises a releasable lock for restraining the datum guide in a desired place.

26. A tool according to either claim 24 or 25, wherein the stringer support is slidable along the post, and the tool further comprises a releasable lock for restraining the stringer support in a desired place.

27. A tool according to claim 26, further comprising a first graduated scale on the post, such that the position of the stringer support along the post can be measured.

28. A tool according to claim 25, further comprising a second graduated scale on the post, such that the position of the datum guide along the post can be measured.

29. A tool according to any one of claims 24 to 28, wherein the stringer support includes one or more seats, and at least a locating portion of the upper end of the stringer is shaped to locate in one of the seats.

30. A method of locating an upper end of a stair case stringer relative to a datum surface, the stringer including a locating portion at the upper end, and the method involving:

providing a tool according to any one of claims 24 to 29;

locating the datum guide on the datum surface; and

supporting the locating portion of the stringer in the stringer support,

whereby the tool is removable once the stringer has been fixed in place.

31. A method of constructing a stair case according to any one of claims 16 to 21 , wherein the stringer includes a locating portion at the upper end, and the method further involves the method of claim 30.