GB2064615A - Prefabricated metal steps - Google Patents

Abstract

A prefabricated metal step assembly includes stringer members (11, 111) to which step treads (29, 129) are to be secured, a number of tread brackets (22, 122) slidingly engageable with the stringer members (11, 111) and the treads (29, 129) extending between and fastened to opposed tread brackets (22, 122). The tread brackets (22, 122) each include a hollow part (23, 123) which engages over and closely fits the stringer members (11, 111), and a tread supporting part (24, 124) integral with the hollow part. The tread brackets (22, 122) are secured to the stringer members (11, 111) by bolts, screws or the like, and the tread supporting part (24, 124) is angled relative to the angle at which the stringers are mounted such that the treads (29, 129) fastened to the supporting parts lie substantially horizontally. <IMAGE>

Description

SPECIFICATION Prefabricated metal steps Background of the Invention This invention relates to prefabricated metal framed steps and relates particularly to a prefabricated step assembly which is assembled on site from prefabricated structural members.

A set of steps such as is often constructed to lead to an entrance or verandah are generally formed of brick, concrete treads set on a brick foundation, or timber forming both the treads of the steps and the supports therefore. Where brick or concrete steps are formed, it is necessary to pour a suitable foundation for the steps and to then construct the necessary brickwork which either forms the steps themselves or forms the support for concrete treads subsequently set on the brick foundation. Where timber steps are installed, the inclined stringers are of relatively heavy timber which is rebated to receive the timber treads.Because installations of sets of steps vary either in the height of the steps, the number of steps in each set, the length of the steps and their width, it is difficult to produce a standardized prefabricated set of steps which may be used for various installations.

A number of attempts have been made to provide standardized sets of steps but to date such attempts have been unsuccessful. Australian Patent No. 458505 to Gilbert Loix describes a construction of staircase utilizing prefabricated components of extruded sections having a Figure-8 cross-section. However, such a structure is relatively difficult to erect, is relatively expensive to produce and is generally unsuited to on-site fabrication.

It is an object of the present invention to provide a prefabricated metal framed step assembly which can be factory produced and erected on-site by relatively unskilled labour.

It is also an object of the invention to provide a prefabricated metal framed step assembly which is relatively economical to manufacture and which is simple to install.

It is a further object of the invention to provide a step assembly which can accommodate variations in desired riser height.

Summary of the Invention According to the present invention there is provided a prefabricated metal framed step assembly comprising a pair of stringer members adapted to be secured at a predetermined angle to the horizontal, a plurality of tread brackets each slidingly engageable with a respective one of the stringer members, each bracket including a hollow section engaged over and closely fitting the respective stringer member and adapted to slide therealong, screw means passing through the hollow section to engage the respective stringer member to fix the hollow section in a selected position on the stringer member, and a tread supporting plate extending from the hollow section towards the other stringer member, the tread supporting plate being angled relative to the hollow section so as to lie substantially horizontally, and treads extending between and supported by the tread supporting plates of opposed tread brackets with means to secure the treads to the tread supporting plates.

According to another aspect of the present invention there is provided a prefabricated metal framed step assembly comprising two or more stringer members adapted to be secured at a predetermined angle to the horizontal, a plurality of tread brackets each slidingly engageable with a respective one of the stringer members, each tread bracket including a hollow section engaged over and closely fitting the respective stringer member and adapted to slide therealong, securing means co-operating with the hollow section and the respective stringer member to secure the hollow section in a selected position along the stringer member, and a tread supporting member mounted on the hollow section the tread supporting member being disposed above the hollow section and being angled relative to the hollow section so as to lie substantially horizontally, and treads adapted to engage with the tread supporting members of opposed tread brackets and be supported thereby with means to secure the treads to the tread supporting members.

The manner in which the present invention may be put into practice will now be described, by way of example, with reference to the accompanying drawings.

Brief Description of the Drawings Figure 1 is a sectional side elevational view of one form of a set of steps made according to the invention, Figure 2 is a plan view of the set of steps shown in Figure 1, Figure 3 is a sectional front elevational view of the set of steps of Figure 1, Figure 4 is a perspective view of the tread supporting bracket, Figure 5 is a perspective view of one form of concrete tread, Figure 6 is a sectional side elevational view of another form of a set of steps made according to the invention, Figure 7 is a perspective view of the tread supporting bracket, for use with the steps of Figure 6, and Figure 8 is a sectional front elevational view of the set of steps of Figure 6, taken along the lines 8-8 of Figure 6.

Description of the Preferred Embodiments Referring to Figures 1 to 5 of the drawings the set of steps in accordance with the invention comprises a pair of stringers 11 which are disposed substantially parallel and at an angle to the horizontal. The angle of the stringers is selected to provide a desired riser height commensurate with the width of the tread to be used. In the embodiment illustrated this angle is 330.

In the embodiment illustrated, each stringer 11 is formed of metal of square tubular section, although it will be appreciated that the stringers may be formed of sections of other cross sectional shape including rectangular section, round section and angled section.

The upper end of each stringer 11 is fastened to a supporting structure which, in the present embodiment, comprises a solid wall 12. A bracket 13 is fixed to the wall by bolts 14 and a lug 16 extending from the bracket 13 engages within the end of the hollow stringer 11. A further bolt 17 passing through the upper end of the stringer 11 and lug 1 6 secures the stringer to the bracket 13.

The lower end of each stringer is fixed to a bottom support which may comprise a post 18 securely fixed in a concrete foundation 19. The post 18 may be used simply as a support for the bottom end of the stringer 11 or may also be used to support a hand rail 21, if such is required.

As shown in the drawings, three tread brackets 22 are slidably engaged with each stringer 11.

The tread brackets, which are shown in Figure 4, each comprise a hollow tubular portion 23 having internal dimensions to closely fit the stringers 11, and a tread supporting plate 24 welded to one side of the tubular portion 23. The angle between the axis of the tubular portion 23 and the plane of the plate 24 is the same as that of the stringers 11 to the horizontal, i.e. 330.

Four tapped holes 26 are provided in one side of each tubular portion 23 and allen screws 27 are engaged within the tapped holes 26 to secure the tread brackets 22 in their respective positions along the stringers 11. The position of the tread brackets 22 is determined by the desired riser height as well as the span of the set of steps.

The tread support plates 24 are each provided with two holes 28, and a tread 29 is supported by the plates 24 of opposed tread brackets 22. The treads illustrated comprise reinforced concrete treads, although it will be appreciated that any form of tread including timber treads, solid steel, expanded steel mesh and other tread forms may be ulitized with the structure of the present invention.

The concrete treads 29 include reinforcement 31 to which are secured four bolts 32 which extend from the base of the treads 29 adjacent each end thereof. The bolts 32 engage through the holes 28 in the tread support plates to secure the treads 29 in position.

It will be appreciated that three of the tread brackets 22 are formed with the tread support plate extending from one side of the tubular portion 23 and the other three brackets are formed with the plate extending from the opposite side of the tubular portion.

In use, the various parts of the steps may be constructed in a factory and transported to the site for assembly. The brackets 22 are engaged with the respective stringers 11 prior to securing the stringers in position. When the relative position of the brackets on the stringers is determined to provide the desired riser height, the bracket 22 are secured to the stringers by embedding the allen headed screws 27 into the stringers. The stringers may be supported intermediate their ends by use of additional support posts or the like (not shown).

Referring to Figures 6 to 8 of the drawings, the set of steps in accordance with this aspect of the invention comprises a pair of stringers 111 which are disposed substantially parallel and at an angle to the horizontal. The angle of the stringers is selected to provide a desired riser height commensurate with the width of the tread to be used. In the embodiment illustrated this angle is 330.

In the embodiment illustrated, each stringer 111 is formed of metal of square tubular section, although it will be appreciated that the stringers may be formed of sections of other cross sectional shape including rectangular section, round section and angled section.

The upper end of each stringer 111 is fastened to a supporting structure which, in the present embodiment, comprises a solid wall 112. A bracket 113 is fixed to the wall by bolts 114 and a sleeve 11 6 extending from the bracket 113 engages over the upper end of the hollow stringer 111. Bolts 11 7 passing through the sleeve 11 6 secures the stringer 111 to the bracket 113.

The lower end of each stringer is fixed to a bottom support which may comprise a post 118 securely fixed in a concrete foundation 11 9. The post 118 has an angled extension which engages inside the stringer 111 and is secured thereto by bolts 120.

As shown in the drawings, three tread brackets 122 are slidably engaged with each stringer 111.

The tread brackets 122, which are shown in Figure 7, each comprise a hollow tubular portion 123 having internal dimensions to closely fit the stringers 111, and a tread supporting plate 124 welded to support members 125 on the top of the tubular portion 123. The angle between the axis of the tubular portion 123 and the plane of the plate 124 is the same as that of the stringers 111 to the horizontal, i.e. 330, so-that the treads are substantially horizontal. The support members 125 include plates 133 and 134 extending upwardly from the top surface of the tubular member 123 substantially co-planar with the ends thereof. The height of each plate 1 33 and 134 is calculated to provide the desired angle between the plane of the tread support plate 124 and the axis of the tubular portion 123. The tread support plate is welded to the upper edges of the plates 133 and 134 and a further angled plate 135 is welded in position, as shown, to provide the required structural rigidity. If desired, a further plate (not shown) may be provided substantially co-planar with at least one side of the tubular member either in addition to or instead of one or more of the plates 133,134 and 135.

Four tapped holes 126 are provided in the bottom side of each tubular portion 123 and allen screws or bolts 127 are engaged within the tapped holes 126 to secure the tread brackets 122 in their respective positions along the stringers 111. The position of the tread brackets 1 22 along the stringers 111 is determined by the desired riser height as well as the span of the set of steps.

The tread support plates 124 are each provided with two holes 128, and a tread 129 is supported by the plates 124 of opposed tread brackets 122.

The treads illustrated comprise timber treads, although it will be appreciated that any form of tread including reinforced concrete, solid steel, expanded steel mesh and other tread forms may be utilized with the structure of the present invention.

The treads 129 are drilled with four holes to receive bolts 132 which extend from the base of the treads 129 adjacent each end thereof. The bolts 132 engage through the holes 128 in the tread support plates to secure the treads 129 in position.

It will be appreciated that all tread brackets 122 are substantially identical and support the treads 129 above the level of the stringers 111 so that the treads may extend beyond the tread brackets on each side by any suitable distance.

Also, for treads of extended length, three or more stringers may be used to provide adequate support for the treads.

If the step installation requires a hand-rail, a hand-rail post 137 can be secured to one of the tread brackets 122 by being provided with a base plate 1 38 which is bolted to the upper surface of the tread 129 with the bolts 132. Intermediate supports for the hand-rail may be similarly mounted, and the upper end of the hand-rail is supported on a post which is integral with the bracket 113.

In use, the various parts of the steps may be constructed in a factory and transported to the site for assembly. The brackets 122 may be engaged with the respect stringers 111 prior to securing the stringers in position. When the relative position of the brackets on the stringers is determined to provide the desired riser height, the brackets 122 are secured to the stringers by embedding the allen headed screws or bolts 127 into the stringers. The stringers may be supported intermediate their ends by use of additional support posts or the like which are adapted to engage with either the stringer 111 or with one of the intermediate tread brackets.

Claims (5)

1. A prefabricated metal framed step assembly comprising a pair of stringer members adapted to be secured at a predetermined angle to the horizontal, a plurality of tread brackets each slidingly engageable with a respective one of the stringer members, each tread bracket including a hollow section engaged over and closely fitting the respective stringer member and adapted to slide therealong, fastening means passing through the hollow section to engage the respective stringer member to fix the hollow section in a selected position on the stringer member, a tread supporting plate extending from the hollow section towards the other stringer member, the tread supporting plate being angled relative to the hollow section so as to lie substantially horizontally, and treads extending between and supported by the tread supporting plates of opposed tread brackets with means to secure the treads to the tread supporting plates.

2. A step assembly as claimed in claim 1 wherein the tread supporting plate extends from one side of each hollow section.

3. A step assembly as claimed in claim 1 wherein the stringers are hollow and the upper ends of the stringer members are secured to a support by means of brackets fastened to the support, the brackets having angularly extending lugs which engage within and are secured to the hollow stringers.

4. A prefabricated metal framed step assembly comprising two or more stringer members adapted to be secured at a predetermined angle to the horizontal, a plurality of tread brackets each slidingly engageable with a respective one of the stringer members, each tread bracket including a hollow section engaged over and closely fitting the respective stringer member and adapted to slide therealong, securing means co-operating with the hollow section and the respective stringer member to secure the hollow section in a selected position along the stringer member, and a tread supporting member mounted on the hollow section, the tread supporting member being disposed above the hollow section and being angled relative to the hollow section so as to lie substantially horizontally, and treads adapted to engage with the tread supporting members of opposed tread brackets and be supported thereby with means to secure the treads to the tread supporting members.

5. A step assembly as claimed in claim 4 wherein said tread supporting member is integral with said hollow member.