GB2545506A

GB2545506A - Stair tread

Info

Publication number: GB2545506A
Application number: GB1522460.3A
Authority: GB
Inventors: Rix Tom
Original assignee: Klm Eng Ltd
Current assignee: Klm Eng Ltd
Priority date: 2015-12-18
Filing date: 2015-12-18
Publication date: 2017-06-21
Anticipated expiration: 2035-12-18
Also published as: GB2545506B; GB201522460D0

Abstract

A stair tread assembly 2 for a staircase 1, the assembly comprising a base member 10 and one or more reinforcing members 8 mounted to the base member. The one or more reinforcing members being at least partially embedded a tread formed by the base member. The assembly may be configured to extend laterally across a staircase 1 with the one or more reinforcing members being arranged to extend laterally across the base member. The base member may be elongated along a longitudinal axis with the one or more reinforcing members extending substantially parallel to this axis. The one or more reinforcing members may comprise at least one mounting section for mounting the reinforcing member to the base member, and at least one raised section. Also disclosed is a method for fabricating the stair tread assembly and a tray 7 (figure 2) for forming a stair tread.

Description

STAIR TREAD TECHNICAL FIELD

The present disclosure relates to a stair tread. The present disclosure also relate to a staircase comprising a plurality of stair treads. The present disclosure also relates to a method of fabricating a stair tread and a staircase.

BACKGROUND

Precast concrete stair treads are known. For example, US 3,834,098 and US 3,851,431 disclose stair treads which are cast from concrete in a mould. A clip having a central web and edge flanges is cast into the concrete. The central web provides a mounting structure for mounting the stair tread to a central stringer to form a staircase. The edge flanges support reinforcing steel members. A shortcoming of known concrete stair treads is the thickness of concrete required to ensure that the tread does not crack under normal use. A typical concrete tread can have a thickness of 60mm or more. Due to the thickness of the concrete, the stair treads are heavy and must be supported by a substantial structure. This typically results in greater costs and the increased weight may present problems during assembly and installation of the staircase

It is against this backdrop that the present invention has been conceived. At least in certain embodiments, the present invention seeks to overcome or ameliorate at least some of the problems associated with known concrete stair treads.

SUMMARY OF THE INVENTION

Aspects of the present invention relate to a stair tread; to a staircase comprising a plurality of stair treads; and to a method of manufacturing a stair tread.

According to a further aspect of the present invention there is provided a stair tread assembly for a staircase, the stair tread assembly comprising: a base member; one or more reinforcing member mounted to the base member; and a tread formed on said base member; wherein the one or more reinforcing member is at least partially embedded in the tread. This arrangement allows the depth of the tread to be reduced, thereby reducing the mass of the stair tread assembly. The stair tread assembly may be supported in a framework of the staircase. The tread may be formed in situ on said base member. The stair tread assembly may be pre-formed, for example by forming the tread before the staircase assembly is mounted to the framework. Alternatively, the tread may be formed after the base member has been installed in the framework. During fabrication the base member may form at least a portion of a mould cavity for moulding the tread. The arrangement of the one or more reinforcing member within the tread may increase the strength of the tread. The base member may extend over an underside of the tread.

The stair tread assembly has left and ride sides, a front and a back. When the stair tread assembly is installed in a staircase, the base member extends laterally across the staircase. The one or more reinforcing member may be arranged to extend laterally across the stair tread assembly. The stair tread assembly may consist of one or more reinforcing member which extends laterally. At least in certain embodiments, the stair tread assembly may be formed without any reinforcing members extending from the front to the back of the base member. The base member is elongated along a longitudinal axis which, in use, extends laterally across the width of the staircase. The one or more reinforcing member may be arranged to extend substantially parallel to said longitudinal axis.

The one or more reinforcing member may each comprise: at least one mounting section for mounting the reinforcing member to the base member; and at least one raised section. The at least one raised section may be embedded within the tread. The at least one mounting section may be fixedly mounted to the base member, for example by welding or brazing. The at least one raised section may be spaced apart from the base member. A space may be formed between the at least one raised section and the base member. The space(s) may be filled with concrete such that the base member and the tread are interlocked.

The mounting sections of adjacent reinforcing members may be offset from each other in a longitudinal direction. This offset may help to reduce localised cracking which might otherwise occur if the mounting sections were aligned with each other due to localised thinning of the tread. This arrangement may help to reduce or inhibit crack propagation within the tread.

The at least one mounting section may be disposed along a first longitudinal axis; and the at least one raised section may be disposed along a second longitudinal axis. The first and second longitudinal axes may be offset from each other.

The interface between each mounting section and each raised section may comprise one or more bends in the reinforcing member. The one or more bends may each have an acute bend angle. The bend angle may be less than or equal to 45°, 35° or 25°. By including relatively small bend angles, longitudinal loads may be transferred effectively along the reinforcing member. In a variant, the interface between each mounting section and each raised section may comprise a substantially continuous curve.

The one or more reinforcing member may comprise a first reinforcing member comprising first, second and third mounting sections. The first and second mounting sections may be disposed at opposite ends of the first reinforcing member. The third mounting section may be disposed between said first and second mounting sections, for example at a mid-point of the first reinforcing member.

The one or more reinforcing member may comprise a second reinforcing member comprising first and second mounting sections. The first and second mounting sections may be disposed at respective ends of the first reinforcing member.

The first reinforcing member may be longer than the second reinforcing member.

The first and second reinforcing members may be arranged symmetrically about a transverse centreline of the stair tread.

The one or more reinforcing member may each comprise an elongate rod or wire. The elongate rod or wire may be made of metal.

The tread may be formed from a curable material which is cured from a liquid (or semiliquid) state to a solid state. The curable material may be a cementitious material. By way of example, suitable cementitious materials include Portland cement, fly ash, ground granulated blast furnace slag (GGBS), limestone fines and silica fume. An aggregate or particulate material may be incorporated into the curable material, for example to form concrete. The tread may be formed by pouring the curable material in a liquid or semiliquid state over the base member at least partially to embed said one or more reinforcing member therein and then to cure said material to form the tread.

At least one sidewall may be connected to the base member. In certain embodiments, the base member may comprise a plurality of sidewalls. The sidewalls may be associated with respective sides of the base member. The base member and the at least one sidewall may form an open mould for receiving a curable material to form the tread. The mould may, for example, be in the form of a tray. The tray may comprise four sidewalls. The base member may be substantially rectangular.

The base member may comprise one or more mechanical fastener for mounting to a support member. The mechanical fastener may be in the form of a stud, such as a clinch stud.

The stair tread assembly may comprise at least one insert embedded in said tread for mounting a stanchion to support a handrail. The at least one insert may be a cylindrical insert. The at least one insert may have a central axis which is arranged vertically. The stair tread assembly may comprise first and second inserts disposed at respective ends of the tread.

The base member may be formed from sheet steel. The base member and the at least one sidewall may be formed by folding a single piece of sheet steel.

The stair tread assembly may be configured to be mounted directly to a load-bearing stringer. Alternatively, the stair tread assembly may comprise a support assembly for supporting the base member and the tread. The base member may be mounted to the support assembly, for example by one or more mechanical fastener. The support assembly may be formed from sheet metal.

The support assembly may comprise interlocking means for interlocking with a like support assembly. The interlocking means may comprise one or more locking tabs for locating in a corresponding aperture.

According to a further aspect of the present invention there is provided a staircase comprising a plurality of stair tread assemblies as described herein.

According to a yet further aspect of the present invention there is provided a method of fabricating the stair tread assembly described herein, the method comprising: introducing a curable material into said tray such that the one or more reinforcing member mounted to the base member is at least partially embedded within the curable material; and curing said curable material in said tray to form the tread.

The curable material may be a cementitious material. By way of example, suitable cementitious materials include Portland cement, fly ash, ground granulated blast furnace slag (GGBS), limestone fines and silica fume. An aggregate or particulate material may be provided in the cementitious material to form concrete.

According to a further aspect of the present invention there is provided a tray for forming a stair tread, the tray comprising: a base member; one or more reinforcing member mounted to the base member; and at least one sidewall connected to said base member to form a mould cavity for receiving a curable material to form a tread.

According to a further aspect of the present invention there is provided a method of fabricating a staircase, the method comprising assembling a plurality of trays as described herein to form a framework of said staircase; and then introducing a curable material into the mould cavity formed in each tray to form the treads of said staircase. Thus, the curable material may be introduced into the mould cavities after the trays have been assembled to form the framework of said staircase. It will be appreciated that the trays may more readily be manipulated without the treads in place, thereby facilitating assembly of the framework of the staircase.

Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the present invention will now be described, by way of example only, with reference to the accompanying Figures, in which:

Figure 1 shows an exploded perspective view of a staircase comprising a plurality of stair treads in accordance with an embodiment of the present invention;

Figure 2 shows a perspective view of a stair tread assembly according to an embodiment of the present invention;

Figure 3 shows a plan view of the stair tread assembly shown in Figure 2;

Figure 4 shows a front elevation of the stair tread assembly shown in Figure 2;

Figure 5 shows a front elevation of a first reinforcing member mounted to a base member of the stair tread assembly shown in Figure 2;

Figure 6 shows a front elevation of a second reinforcing member mounted to a base member of the stair tread assembly shown in Figure 2;

Figure 7 shows a perspective view of a support assembly for the stair tread assembly shown in Figure 2;

Figure 8 shows a plan view of the support assembly shown in Figure 7;

Figure 9 shows a side elevation of the support assembly shown in Figure 7;

Figure 10 shows a side elevation of the assembled staircase shown in Figure 1; and

Figure 11 shows a front elevation of the assembled staircase shown in Figure 1. DETAILED DESCRIPTION A staircase 1 comprising a plurality of stair tread assemblies 2 in accordance with an embodiment of the present invention is illustrated in Figure 1. The staircase 1 comprises a plurality of the stair tread assemblies 2 fastened to first and second lateral support members 3-1, 3-2.

The stair tread assemblies 2 each comprise a tread sub-assembly 5 and a support sub-assembly 6. With reference to Figures 2, 3 and 4, the tread sub-assembly 5 comprises a tray 7, a plurality of reinforcing members 8 and a tread 9. The tread 9 is formed from a curable material which is initially in a liquid (or semi-liquid) state and is cured to a solid state to form the tread 9. In the present embodiment the material is a cementitious material comprising an aggregate to form a concrete tread 9. The tray 7 has a longitudinal axis X, a transverse axis Y and a vertical axis Z. The tray 7 is elongated along said longitudinal axis X and, in use, extends laterally across the width of the staircase 1. The tray 7 in the present embodiment has a length of 1309mm, a width of 291.5mm and a depth of 30mm. The tray 7 is configured to form a mould for forming the concrete tread 9 in situ. The tray 7 is formed from sheet metal and comprises a rectangular base member 10 and four (4) sidewalls 11. In particular, the tray 7 includes a front sidewall 11 A, a rear sidewall 11B, a left sidewall 11C and a right sidewall 11D which project vertically upwardly from the sides of the base member 10. The top of the tray 7 is open to facilitate introduction of concrete to form the concrete tread 9. Thus, the tray 7 forms a mould cavity into which the curable material is introduced when in a liquid state. The concrete tread 9 comprises an upper surface 12 which forms a tread surface in the assembled staircase 1.

As shown in Figure 2 and 3, a plurality of threaded studs 13 is fixedly mounted to the base member 10. The studs 13 project downwardly from the base member 10 to enable the tread sub-assembly 5 to be mounted to the support sub-assembly 6. In the present embodiment, the base member 10 has eight (8) clinch studs 13 for mounting the tread sub-assembly 5. In addition, the tread sub-assembly 5 can optionally comprise first and second cylindrical inserts 14-1, 14-2 adapted to mount vertical stanchions for supporting a hand rail (not shown). The first and second cylindrical inserts 14-1, 14-2 are disposed at opposing ends of the concrete tread 9.

The reinforcing members 8 extend substantially parallel to the longitudinal axis X of the base member 10. In the present embodiment the reinforcing members 8 each comprise an elongate metal rod (or wire) having a diameter of approximately 6mm. The reinforcing members 8 are fixedly mounted to the base member 10. The reinforcing members 8 are shaped to form a plurality of mounting sections 15 for mounting to the base member 10; and one or more raised sections 16. In the present embodiment, the reinforcing members 8 are welded to the base member 10 at each of said mounting sections 15. The mounting sections 15 have a first longitudinal axis X1; and the raised section(s) 16 have a second longitudinal axis X2. The first and second longitudinal axes X1, X2 extend substantially parallel to the longitudinal axis X and are offset vertically from each other. The reinforcing members 8 are configured such that the raised sections 16 are spaced apart from the base member 10, as shown in Figure 4. When concrete is introduced into the tray 7 in a liquid “wet” state, the concrete fills the space between the raised sections 16 and the base member 10. Once the concrete has cured, the raised sections 16 are embedded within the concrete tread 9, thereby inter-connecting the concrete tread 9 and the base member 10.

With reference to Figures 2 to 6, the tread sub-assembly 5 comprises two different types of reinforcing members 8, referred to herein as first and second reinforcing members 8-1, 8-2. The first and second reinforcing members 8-1, 8-2 extend parallel to the longitudinal axis X of the tread sub-assembly 5 and are arranged in an alternating sequence along the transverse axis Y. A spacing of approximately 24mm is maintained between the first and second reinforcing members 8-1, 8-2 along the transverse axis Y. As shown in Figures 2, 3 and 4, the first reinforcing members 8-1 are longer than the second reinforcing members 8-2. The first reinforcing members 8-1 have a length of 1210mm; and the second reinforcing members 8-2 have a length of 605mm. As shown in Figure 5, the first reinforcing members 8-1 each comprise first and second mounting sections 15-1, 15-2 disposed at opposite ends of the first reinforcing member 8-1; and a third mounting section 15-3 disposed centrally between said first and second mounting sections 15. The first, second and third mounting sections 15-1, 15-2, 15-3 of the first reinforcing members 8-1 each have a length of approximately 30mm. First and second raised sections 16-1, 16-2 extend between the mounting sections 15 of each first reinforcing member 8-1. Angled sections are disposed between said mounting sections 15 and said raised sections 16. The angled sections define an internal angle of approximately 155° with the mounting sections 15 and the raised sections 16. As shown in Figure 6, the second reinforcing members 8-2 each comprise first and second mounting sections 15-1, 15-2 disposed at respective ends thereof. The first and second mounting sections 15-1, 15-2 of the second reinforcing members 8-2 each have a length of approximately 30mm. A raised section 16 extends between the first and second mounting sections 15. It will be appreciated that the first and second reinforcing members 8-1, 8-2 are fixedly mounted at each end to the base member 10 of the tray 7. Angled sections are disposed between said mounting sections 15 and said raised sections 16. The angled sections define an internal angle of approximately 155° with the mounting sections 15 and the raised sections 16.

The first, second and third mounting sections 15-1, 15-2, 15-3 in the first reinforcing member 8-1 are offset from the first and second mounting sections 15-1, 15-2 in the second reinforcing member 8-2. The raised sections 16 are at the same height in the first and second reinforcing members 8-1, 8-2. In an alternate arrangement, the raised sections 16 in the first and second reinforcing members 8-1, 8-2 can be at different heights. In a variant, one or more reinforcing member could extend in a transverse direction, for example between the first and second reinforcing members 8-1, 8-2.

The tray 7 is fabricated from a metal sheet folded to form the base member 10 and the sidewalls 11. As shown in Figure 2, the front and rear sidewalls 11 A, 11B have end tabs 17 which locate inside the left and right sidewalls 11C, 11D to reinforce the tray 7. The front sidewall 11A comprises a rectangular section to provide additional reinforcing at the front of the stair tread assembly 2. As outlined above, the reinforcing members 8 are welded to the base member 10. The studs 13 are located in apertures formed in the base member 10. The studs 13 can be a restriction fit in the apertures (or can have a noncircular profile) to inhibit rotation to facilitate tightening of a nut during assembly of the staircase 1. The tray 7 is used as a mould to form the concrete tread 9 in situ. The concrete is introduced into the tray 7 in a liquid “wet” state up to the level of the top of the sidewalls 11A-D. The sidewalls 11A-D extend above the vertical height of the raised sections 16 of the first and second reinforcing members 8-1, 8-2 such that the concrete completely covers the raised sections 16. The concrete and/or the tray 7 can then be agitated to help ensure that the concrete penetrates the spaces formed between the raised sections 16 of the reinforcing members 8 and the base member 10. The concrete is then allowed to cure within the tray 7. At least the raised sections 16 of the reinforcing members 8 are embedded within the concrete tread 9. The tray 7 and the concrete tread 9 are thereby keyed together. It will be understood that the reinforcing members 8 reinforce the concrete tread 9. By alternating the first and second reinforcing members 8-1, 8-2 in said transverse direction Y, crack propagation within the concrete tread 9 may be controlled. In the present embodiment the concrete tread 9 can be moulded within the tray 7 without the need to use additional mould components, for example without using additional mould battens or the like to form one or more sidewall.

The support sub-assembly 6 will now be described with reference to Figures 7, 8 and 9. The support sub-assembly 6 is formed from sheet metal and comprises a support member 18, a vertical member 19, a front section 20 and first and second end plates 21-1, 21-2. The support member 18 is arranged for supporting the tread sub-assembly 5 and comprises apertures 22 for receiving the studs 13. A reinforcing web 23 is fixedly mounted to an underside of the support member 18 to provide reinforcement in a longitudinal direction. The vertical member 19 extends substantially vertically between adjacent stair tread assemblies 2 in the staircase 1. As shown in Figures 7 and 9, the vertical member 19 comprises three (3) locking tabs 24 for cooperating with an adjacent support sub-assembly 6. The front section 20 comprises a channel 25 having a C-section and arranged to form an underside of the front of the stair tread assembly 2. The channel 25 comprises three (3) elongate apertures 26 extending parallel to the longitudinal axis X of the stair tread assembly 2. The elongate apertures 26 are arranged to receive the locking tabs 24 of an adjacent stair tread assembly 2. The first and second end plates 21-1, 21-2 are disposed at respective ends of the support member 18 and are arranged to mount the support sub-assembly 6 to the first and second lateral support members 3-1, 3-2. In particular, the first and second end plates 21-1, 21-2 each comprise two (2) vertical slots 28 for receiving studs (not shown) to fasten the support sub-assembly 6 to the first and second lateral support members 3-1, 3-2. The studs typically comprise locking nuts and bolts.

The assembly of the staircase 1 will now be described with reference to Figures 1,10 and 11. The support sub-assembly 6 for each stair tread assembly 2 is fastened to the first and second lateral support members 3-1, 3-2. The locking tabs 24 formed in the vertical member 19 are located in the elongate apertures 26 of the adjacent support sub-assembly 6 to provide an interlocking arrangement. A support framework of the staircase 1 is thereby formed. A tread sub-assembly 5 incorporating a concrete tread 9 is then mounted to the support sub-assembly 6. In particular, the studs 13 mounted to the base member 10 are located in the apertures 22 formed in the support member 18. The tread sub-assembly 5 is mounted to the support sub-assembly 6 by applying nuts to the studs 13. A bottom bracket 29 shown in Figure 1 is mounted to the lowermost support sub-assembly 6 in the staircase 1. A hand rail (not shown) can be mounted to the staircase 1 by installing vertical stanchions in the first and second cylindrical inserts 14-1, 14-2. It will be appreciated that the assembly sequence of the staircase 1 could be modified by mounting the tread assemblies 5 to the respective support assemblies 6 prior to mounting to the first and second lateral support members 3-1, 3-2. The assembled staircase 1 is shown in Figures 10 and 11. In this embodiment, the staircase 1 comprises eleven (11) stair tread assemblies 2 and has a vertical dimension of 1925mm and a horizontal dimension of 3120.5mm.

The moulding of the concrete tread 9 within the tray 7 facilitates fabrication of the tread sub-assembly 5. Furthermore, the arrangement of the reinforcing members 8 within the concrete tread 9 allows the depth of the concrete tread 9 (measured along the vertical axis Z) to be reduced when compared to other concrete treads.

It will be appreciated that various changes and modifications can be made to the staircase 1 described herein without departing from the scope of the present invention. For example, the tray 7 could be modified such that one or more sidewall 11A-D include an inwardly-directed projection for keying with the concrete used to form the concrete tread 9. The dimensions of each stair tread assembly 2 can be adjusted. Moreover, the number of stair tread assemblies 2 used to form the staircase 1 can be varied, for example to suit different building applications.

Claims

CLAIMS:

1. A stair tread assembly for a staircase, the stair tread assembly comprising: a base member; one or more reinforcing member mounted to the base member; and a tread formed on said base member; wherein the one or more reinforcing member is at least partially embedded in the tread.
2. A stair tread assembly as claimed in claim 1, wherein the stair tread assembly is configured to extend laterally across a staircase; and the one or more reinforcing member is arranged to extend laterally across the base member.
3. A stair tread assembly as claimed in claim 2, wherein the stair tread assembly consists of one or more reinforcing member extending laterally across the stair tread assembly.
4. A stair tread assembly as claimed in any one of claim 1, 2 or 3, wherein the base member is elongated along a longitudinal axis, the one or more reinforcing member extending substantially parallel to said longitudinal axis.
5. A stair tread assembly as claimed in any one of claims 1 to 4, wherein said one or more reinforcing member each comprise: at least one mounting section for mounting the reinforcing member to the base member; and at least one raised section.
6. A stair tread assembly as claimed in claim 5, wherein the mounting sections of adjacent reinforcing members are offset from each other in a longitudinal direction.
7. A stair tread assembly as claimed in claim 5 or claim 6, wherein a first reinforcing member comprises first, second and third mounting sections; wherein the first and second mounting sections are disposed at respective ends of the first reinforcing member; and the third mounting section is disposed between said first and second mounting sections.
8. A stair tread assembly as claimed in any one of claims 5, 6 or 7, wherein a second reinforcing member comprises first and second mounting sections; wherein the first and second mounting sections are disposed at respective ends of the first reinforcing member.
9. A stair tread assembly as claimed in claims 7 and 8, wherein said first reinforcing member is longer than said second reinforcing member.
10. A stair tread assembly as claimed in any one of the preceding claims, wherein said one or more reinforcing member each comprise an elongate rod.
11. A stair tread assembly as claimed in any one of the preceding claims, wherein the tread is formed from a cured material.
12. A stair tread assembly as claimed in claim 11, wherein the cured material comprises a cementitious material.
13. A stair tread assembly as claimed in any one of the preceding claims, wherein the tread is formed by pouring a curable material in a liquid or partially-liquid state over the base member at least partially to embed said one or more reinforcing member therein and curing said material to form the tread.
14. A stair tread assembly as claimed in any one of the preceding claims, wherein at least one sidewall is connected to the base member.
15. A stair tread assembly as claimed in any one of the preceding claims, wherein the base member comprises one or more mechanical fastener for mounting to a support member.
17. A stair tread assembly as claimed in any one of the preceding claims comprising at least one insert embedded in said tread for mounting a stanchion to support a handrail.
18. A stair tread assembly as claimed in any one of the preceding claims, wherein the base member is formed from sheet steel.
19. A stair tread assembly as claimed in any one of the preceding claims comprising a support assembly for supporting the base member and the tread. 20 A stair tread assembly as claimed in claim 19, wherein said support assembly comprises interlocking means for interlocking with a like support assembly.
21. A staircase comprising a plurality of stair tread assemblies as claimed in any one of the preceding claims.
22. A method of fabricating the stair tread assembly claimed in any one of claims 1 to 19, the method comprising: introducing a curable material into said tray such that the one or more reinforcing member mounted to the base member is at least partially embedded within the curable material; and curing said curable material in said tray to form the tread.
23. A method as claimed in claim 22, wherein the curable material comprises a cementitious material.
24. A tray for forming a stair tread, the tray comprising: a base member; one or more reinforcing member mounted to the base member; and at least one sidewall connected to said base member to form a mould cavity for receiving a curable material to form a tread.
25. A method of fabricating a staircase, the method comprising assembling a plurality of trays as claimed in claim 24 to form a framework of said staircase; and then introducing a curable material into the mould cavity formed in each tray to form the treads of said staircase.
26. A stair tread assembly substantially as herein described with reference to the accompanying figures.
27. A staircase substantially as herein described with reference to the accompanying figures.
28. A tray for forming a stair tread substantially as herein described with reference to the accompanying figures.