U.S. patent application number 12/308537 was filed with the patent office on 2010-11-25 for stairway for use on building sites.
Invention is credited to John Clement Preston.
Application Number | 20100293875 12/308537 |
Document ID | / |
Family ID | 38832999 |
Filed Date | 2010-11-25 |
United States Patent
Application |
20100293875 |
Kind Code |
A1 |
Preston; John Clement |
November 25, 2010 |
Stairway for Use on Building Sites
Abstract
The invention is a portable, modular stairway unit for use on a
building site during construction of a multistorey building, the
stairway unit including: a stair run section with a plurality of
rise-separated stair treads, the stair run section having an upper
and a lower end; an upper landing connected to the stair run
section at, or at a distance from, the upper end of the stair run
section; a lower landing connected to the stair run section at, or
at a distance from, the lower end of the stair run section; wherein
each of the landings have portions that extend laterally beyond a
width of the stair run section, the landings being devised to
extend inwardly into respective upper and lower storey levels of
the building when the stairway unit is situated adjacent to a face
of the building; and anchoring means arranged to removeably secure
the landings, in use, at the upper and lower storey levels thereby
to provide a double-cantilevered mounting of the stair run section
extending between the two building storey levels.
Inventors: |
Preston; John Clement; (New
South Wales, AU) |
Correspondence
Address: |
David J. Hill;Chambliss, Bahner & Stophel, P.C.
1000 Tallan Building, Two Union Square
Chattanooga
TN
37402
US
|
Family ID: |
38832999 |
Appl. No.: |
12/308537 |
Filed: |
June 20, 2007 |
PCT Filed: |
June 20, 2007 |
PCT NO: |
PCT/AU2007/000863 |
371 Date: |
June 3, 2010 |
Current U.S.
Class: |
52/183 |
Current CPC
Class: |
E04F 11/022 20130101;
E04G 27/00 20130101 |
Class at
Publication: |
52/183 |
International
Class: |
E04G 27/00 20060101
E04G027/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 20, 2006 |
AU |
2006903316 |
Claims
1. A portable, modular stairway unit for use on a building site
during construction of a multistorey building, the stairway unit
including: a stair run section with a plurality of rise-separated
stair treads, the stair run section having an upper and a lower
end; an upper landing connected to the stair run section at, or at
a distance from, the upper end of the stair run section; a lower
landing connected to the stair run section at, or at a distance
from, the lower end of the stair run section; wherein each of the
landings have portions that extend laterally beyond a width of the
stair run section, the landings being devised to extend inwardly
into respective upper and lower storey levels of the building when
the stairway unit is situated adjacent to a face of the building;
and anchoring means arranged to removeably secure the landings, in
use, at the upper and lower storey levels thereby to provide a
double-cantilevered mounting of the stair run section extending
between the two building storey levels.
2. The stairway unit according to claim 1, wherein at least one of
the landings is pivotably secured to the stair run section in such
a manner as to allow the incline of the stair run section to be
varied with respect to the at least one landing.
3. The stairway unit according to claim 2, wherein each of the
landings is hinged to the respective ends of the stair run
section.
4. The stairway unit according to claim 1, wherein at least one of
the landings is secured to the stair run section in such a manner
as to allow linear movement along a longitudinal axis of the stair
run section, and further including fixing means to secure the
landing at a desired position along the stair run section, whereby
a distance between the upper and lower landings of the stair run
section can be varied and fixed at desired positions.
5. The stairway unit according to claim 4, wherein the lower
landing is arranged to be held at a fixed angle of inclination with
respect to the longitudinal axis of the stair run section.
6. The stairway unit according to claim 4 or 5, wherein the stair
run section includes discrete fastening points spaced apart along
the longitudinal extension of the stair run section.
7. The stairway unit according to any one of the above claims,
further including means to secure the upper landing at a
predetermined angle with respect to the stair run section.
8. The stairway unit according to claim 7, wherein the
predetermined angle is from about 26.5.degree. to 45.degree. from
the horizontal.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to stairs, in particular to
stairways suitable for temporary erection and use on a building
site during construction of a building.
BACKGROUND OF THE INVENTION
[0002] Temporary stairways are often required on building sites
during construction of a multistorey building to allow construction
workers to move from one storey of the building to another.
[0003] Whilst permanent stairways are often formed at the same time
as the floor slabs of the storeys, making the rough (eg concrete
cast) stairways safe for use by workmen requires additional onsite
construction, ie installation of security items such as handrails,
anti-slip stair tread surfaces, and similar. More importantly, the
stairwells of permanent stairways are often located within the
building or at one end thereof, such that during construction work,
when workers are working at different locations within the
building, additional travel time is required to access the
stairways. This inconvenience is exacerbated if materials are also
required to be transported between building levels, as several
trips from distant locations might be required.
[0004] To speed up the process and have a more efficient
environment for building workers, temporary stairways can be
erected at numerous locations around the building under
construction, and then removed either when construction is
complete, or when the permanent stairways are completed and safe
for use.
[0005] For multistorey buildings, temporary stairways are typically
provided at or within the scaffolding structure present on the
outside faces of the building. For example, U.S. Pat. No. 3,684,057
discloses a portable stairway comprised of step-ladder-like
sections which are releasably lockably mounted onto outrigger
supports which in turn are releasably lockably secured to the
scaffolding's upright struts. Safety side guard rails are hingedly
attached to supporting posts which in turn are pivotedly mounted to
the step-ladder side frame members.
[0006] Whilst portable stairway assemblies that are incorporated
into scaffolding have found increasing use in the building sector,
the disadvantage of such scaffolding stairway structures is that
they require the presence of an external scaffold, and
incorporation of numerous additional structural components, in
particular to secure the modular step-ladder sections onto the
scaffolding for example.
[0007] Another problem that exists with such types of
modular/portable stairways is that they lack floor-height
adjustability, ie they are designed for a discrete storey height
between the floor levels of a lower and adjacent upper storey. The
inclination angle of the stair run section, being that part of the
stairway which incorporates the plurality of individual steps (each
defined by a vertical rise and horizontal run) with regard to the
horizontal is mostly confined to discrete values, given that
building codes require minimum dimensional safety standards for
each step in the stair run. For example, the rise and tread of each
individual step may be fixed such that the rise shall not exceed
215 mm, whereas the tread shall not have an extension of less than
215 mm; industry practice is to use stair rise to tread ratio
formulae in making the stair run sections.
[0008] In the construction and transport industry it is also known
to utilise height-adjustable and self-height-adjustable stair
constructions wherein a plurality of tread boards are disposed in
parallel, stepped relationship and moveably fixed onto a pair of
opposing longitudinal stringers with terminal end links traverse
thereto. The stringers and links are pivotably joined such as to
provide a parallelogram frame structure which supports the stair
treads. As noted, the stair treads span between the longitudinal
stringers, and the stairs can therefore be manipulated as a
flexible assembly to meet a desired inclination or pitch angle of
the stringers required to span any desired height, whereby the
tread boards remain substantially horizontal, but the rise will
vary in accordance with the change of inclination angle. Examples
of such adjustable stairs may be found in U.S. Pat. No. 3,626,438,
U.S. Pat. No. 3,593,821 and U.S. Pat. No. 4,768,617. It is noted
that whilst these documents all describe height adjustable stairway
constructions, to the knowledge of the applicant, none of these
constructions have been employed in temporary stairway units
between levels of multistorey buildings.
[0009] It is an object of the present invention to provide a
portable stairway unit suitable for use on building sites during
construction of multistorey buildings, which can be deployed in an
assembled state and adjusted for use on buildings with varying
floor to ceiling heights. Preferably, such stairway units should be
modular in layout and incorporate or use fastening or fixing
structures that allow the stairway unit to be temporarily secured
at one building location and be easily removed for deployment at a
different location.
[0010] It would be also advantageous to provide a temporary
stairway construction which can be secured in a detachable manner
to the building without structural damage to building components,
for example building storey floor slabs, walls and the like.
SUMMARY OF THE INVENTION
[0011] According to one aspect of the present invention, there is
provided a portable, modular stairway unit for use on a building
site during construction of a multistorey building, the stairway
unit including:
[0012] a stair run section with a plurality of rise-separated stair
treads, the stair run section having an upper and a lower end;
[0013] an upper landing connected to the stair run section at, or
at a distance from, the upper end of the stair run section;
[0014] a lower landing connected to the stair run section at, or at
a distance from, the lower end of the stair run section;
[0015] wherein each of the landings have portions that extend
laterally beyond a width of the stair run section, the landings
being devised to extend inwardly into respective upper and lower
storey levels of the building when the stairway unit is situated
adjacent to a face of the building; and anchoring means arranged to
removeably secure the landings, in use, at the upper and lower
storey levels thereby to provide a double-cantilevered mounting of
the stair run section extending between the two storey levels.
[0016] Modular stairways in accordance with the present invention
achieve significant cost savings with regards to erection time
given that the stairway can be positioned as a pre-assembled unit
at an outside location adjacent to the building face, whereupon
suitable anchoring of the landings at the upper and lower storeys
secure the stairway module in place.
[0017] Preferably, at least one of the landings is pivotably
secured to the stair run section, to allow the incline of the stair
run section, when in use, to be varied. More preferably, each of
the landings is hinged to the stair run section, as this will allow
the landings to be folded back onto the step section for ease of
transport, when the stairway module is not in use.
[0018] Stairway embodiments incorporating landings that are
articulated or hinged at both an upper and lower end of the stair
run section allow deployment and use of the same stairway unit at
buildings having storey heights (ie distance between floor to floor
of adjoining storeys of the building) that vary within a predefined
narrow range. For example, some multilevel buildings incorporate
floor levels with varying floor to ceiling heights, eg lower levels
having a floor to ceiling height of 2,700 mm, whereas upper floor
levels might have an increased floor-ceiling height of eg 2,900
mm.
[0019] In an alternative form, at least one of the landings is
secured to the stair run section in such a manner as to allow
linear movement along a longitudinal axis of the stair run section,
and further including fixing means to secure the landing at a
desired position along the stair run section, whereby a distance
between the upper and lower landings at the stair run section can
be varied and fixed in a desired position.
[0020] In particular, the lower landing is arranged to be held at a
fixed angle of inclination with respect to the longitudinal axis of
the stair run section, such that the tread and rise of each step
are allowed to remain horizontal and vertical, respectively, as the
stair run section is moved relative to the landing.
[0021] In a preferred and advantageous further embodiment, the
stair run section is devised with a plurality of treads whose
incline with respect to the longitudinal axis of the stair run
section may be selectively varied and fixed in such a manner that
the treads will remain substantially horizontal irrespective of the
angle of incline which the stair run section has when extending
between adjacent building storeys. The variation of step tread
incline is preferentially achieved by providing a linkage mechanism
articulating the individual treads to one another in such a manner
that variation of the incline angle of the stair run section will
resolve in self-adjustment of the treads into a horizontal
attitude. The present invention contemplates use of known
adjustable stair run section construction principles as illustrated
in the aforementioned U.S. patents of Cornell, Lister, Mason and
others.
[0022] Preferably, the anchoring means are provided by
adjustable-height props arranged for loading in compression when
extending between the floor and ceiling of a respective storey
where the respective landing is to be secured. Use of compression
props rather than more conventional anchoring bolts, hooks and
loops avoids damage to the building structure, as there is no need
to drill into the building structure to provide a fixing point or
attachment for the landings of the modular stairway unit. Height
adjustable props are known in the construction industry for
securing form work prior to and subsequent to casting of building
storey slabs. It should be noted, however, that conventional
fasteners such as bolts can also be used, eg to temporarily secure
the landings in deploying the modular stairway.
[0023] An illustrative embodiment of the present invention will now
be described with reference to the accompanying figures. Further
features and advantages of the invention will become apparent from
the accompanying description provided in relation to the
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a schematic side view of a modular stairway
according to one embodiment of the present invention, installed
against an exterior face of and between two storeys of a
building;
[0025] FIG. 2 is a top view along direction of arrow II of the
stairway of FIG. 1;
[0026] FIG. 3 is an end view along direction of arrow III of the
stairway of FIG. 1;
[0027] FIG. 4 is a side view of the stairway of FIG. 1 when in a
transport or non-deployed position;
[0028] FIG. 5 is a schematic, partial side view, of a height
adjustable, modular stairway in accordance with another embodiment
of the present invention.
DESCRIPTION OF PREFERRED EMBODIMENT
[0029] FIG. 1 shows a modular stairway unit 10 in position at the
external face and between an upper storey 12 and a lower storey 14
of a building. The modular stairway unit 10 consists of an upper
landing 16, a lower landing 18, a stair run section 20 extending
between and connected to the landings 16, 18 and four anchoring
members 22a to 22d per landing as described in more detail
below.
[0030] The stair run section 20 essentially includes a plurality of
individual treads 24 in the form of boards, with optional risers 26
extending therebetween. The treads 24 are suitably secured and
supported at their widthward ends at opposed, tread support bar
panels (not shown) in a known manner, for example, that described
in U.S. Pat. No. 3,788,028. Alternatively, a tread-rise adjustable
stair run assembly can be employed, such as that described in U.S.
Pat. No. 3,593,821 or U.S. Pat. No. 4,768,617, allowing, of course,
for the necessary modifications required for incorporation of such
type of adjustable stair run assemblies into the concept of the
present invention.
[0031] FIG. 1 also illustrates schematically at 28 safety fence
structures which are secured to each widthward side of the stair
run section 20, thereby providing added security to users of the
modular stairway unit; a conventional hand rail can be
replaced.
[0032] The stair run section 20 is manufactured and assembled from
materials and components commonly used in portable stairway
manufacture. Preferably, the components are made from sheet and
section steel, allowing the stairway 10 to be weatherproof and
strong enough to withstand significant loads as experienced during
building construction.
[0033] As best seen in FIG. 2, the two landings 16, 18, essentially
rectangular steel plates, each have a portion, identified at 16a,
18a, respectively, that protrudes to one side in widthward
extension beyond the width of the stair run section 20, ie the
landings have outrigger portions that serve to secure the stairway
10 to a building. In deployment of the modular unit 10, as
illustrated in FIGS. 1 and 2, the landing portions 16a, 18a extend
into the building in substantially coplanar horizontal relation
with the floor 12a, 14a of the respective floor levels 12 and 14.
Both the upper and lower landings 16, 18, are secured in
articulated manner (eg using axle hinges) to the upper and lower
ends of the stair run section 20, respectively, thereby allowing
the entire modular unit to be deployed between building storeys
having varying floor 14a to ceiling 14b heights, whilst maintaining
horizontal orientation of the lower and upper landings, 18, 16,
respectively. It will be appreciated that, depending on the height
between ceiling and floor, the inclination angle (i) of the stair
run section 20 varies.
[0034] The entire modular stairway 10 is removably secured such as
to be cantilevered at two locations, namely the upper and lower
floors 12, 14 by means of a total of eight longitudinally
adjustable compression props 22a to 22d of such type as commonly
employed in the building trade, for example screw props. The props
22a to 22c consist essentially of a tubular strut with plate
footings at the lower terminal end, the opposite upper hollow end
of the prop tubes having an internal tread into which externally
threaded stems of prop headers are inserted. It is preferred to
have the mechanism which allows height adjustment (and
tensioning/wedging) of the props to be located at the upper end
(header) of the units, to prevent accidental de-tensioning of the
props during use of the stairway.
[0035] As seen from FIGS. 1 to 4, a total of four props 22a to 22d
is provided per landing 16,18, thereby providing a stable anchoring
arrangement at the bottom and top of the stairway unit at the
building levels, whereby one prop each is situated close to the
corners of the landing platform sections 16a, 18a, thereby to
ensure potential bending and deformation of the landings due to the
weight of the stairway or the load on the stairway being minimised.
The entire arrangement creates a double-cantilever mount of the
stair run section 20 at the building.
[0036] The individual props can be secured to the landings 16, 18
in a known manner, for example by passing the props through
suitably dimensioned through holes in the platforms, and then
securing the relative position of the platforms 16, 18 with respect
to the tubular prop struts. It is preferred that the props will be
welded to the landings during manufacture of the system, to provide
a wholly pre-fabricated unit to minimise erection times. It will be
immediately appreciated that using props to secure and fix/anchor
the modular stairway unit 10 between building storeys makes
installation of the entire unit location independent, since there
is no need to provide for fixed anchoring/fixing locations in the
building structure, for example in the floor slabs.
[0037] It is also possible to dispense with receptacle holes for
the props and instead weld (or otherwise secure) the prop footings
on the upper face of the landing platform sections 16a, 18a; the
headers of all four props 22a to 22d can be extended to engage on
the ceiling surface, whereby further tensioning presses the
elastically deformable steel platform sections securely onto the
storey floor surface thereby to achieve a secure friction-tight
engagement of the landing at the storey floor. If desired, friction
increasing finishings can be present on the surfaces of the
platforms 16, 18.
[0038] As best seen in FIG. 1 but also illustrated in FIGS. 2 and 3
schematically, each landing is provided with a L-shaped fence
structure 30, 32 on the sides facing away from the building,
thereby to ensure safety of the users of the stairway unit, whereby
it is noted that the fence 30, 32 extends into the building storeys
once the unit is mounted and secured in place.
[0039] FIG. 4 shows the modular stairway in a transport position,
where the stair run section 20 extends parallel and horizontal with
the landings 16 and 18, thereby facilitating transport of the
modular stairway unit on a flatbed truck. The modular, articulated
construction of the stairway unit 10 enables the unit to be
transported in pre-assembled manner to the building site, where a
crane lift may be used to hoist the unit into place at the exterior
face of the building.
[0040] As referred to above, in one preferred form, the stair run
section 20 is of such type having height adjustable treads to allow
use of the same modular unit 10 for varying floor level heights.
However, the hinged arrangement of the top and bottom landings 16,
18 at either end of the stair run section 20 itself is capable of
providing a certain degree of adjustability to different floor
level heights (within construction tolerances) given that a change
in the angle of inclination (i) of the stair run's incline
position, where the treads are essentially horizontal, can be
varied by a certain amount without making the entire stairway unit
unsafe.
[0041] The widths and angles of the treads and the distances
between the treads should preferably abide by relevant building
code or standards. For example, the Australian Standard AS
1657-1992 states that stairways shall not be less than 600 mm wide,
and the angle of slope of the stairway should not be less than 26.5
degrees and not greater than 45 degrees, height of each rise shall
be between 150 mm-215 mm, and length of each tread shall be between
215 mm-305 mm.
[0042] FIG. 5 illustrates a modified embodiment of that illustrated
in FIGS. 1 to 4. Similar reference numerals are used in FIG. 5 to
refer to similar components, which will thus not be described in
further detail here. As with the previous embodiment, the upper
landing 16 is hinged to the upper end of stair run section 20,
thereby allowing variation of the angle (ii) between the platform
16 and the notional longitudinal plane (or axis) of section 20. In
contrast to the previous embodiment, however, the lower landing 18
is secured to the stair run section 20 in such a manner as to allow
displacement along the longitudinal axis of section 20 whilst
maintaining a generally horizontal attitude of the landing platform
18. To this end, the landing platform 18 is provided with a support
section 32 defining a sleeve in which the lower terminal end of the
stair run section 20 is received for sliding engagement therewith,
thereby allowing the entire platform structure 18 to be moved up
and down along arrows (iii) along the length of unit 20. Sleeve
member 32 is suitably attached to the side plates or bars 34 of
stair run section 20, wherein a roller connected to the landing 18
is positioned to allow the landing 18 to move relative to and along
bar members 34. When the landing 18 is at a desired position, it is
immobilised with respect and fixed to the stair run section 20, for
example using nut and bolt clamps, locating pins or bolts, etc.
Preferably, a series of holes 36 are present in the side bars of 34
stair run section 20 at different positions, wherein a bolt is
inserted through the support section 32 and into at least one hole
36, thereby securing the landing 18 in the desired position.
[0043] It will be appreciated by persons skilled in the art that
the invention can be implemented in different ways, without
departing from the spirit and scope of the invention.
[0044] Any discussion of documents, devices, acts or knowledge in
this specification is included to explain the context of the
invention. It should not be taken as an admission that any of the
material forms part of the prior art base or the common general
knowledge in the relevant art in Australia on or before the filing
date of the patent application to which the present specification
pertains.
* * * * *