Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02531461 2008-06-16
SCAFFOLD FRAME SECTION WTTH INTEGRAL GUARD RAIL POST
CROSS REFERENCE TO RELATED APPLICATION
This application is being filed contemporaneously with application for U.S.
Design Patent Serial No. 29/237,566, entitled SCAFFOLD FRAME SECTION WTfH
1NTEGRAL GUARD RAIL POST.
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The present invention is broadly concerned with improved scaffold assemblies
and components thereof which are designed for enhanced user safety. More
particularly, the
invention is concerned with scaffold assemblies and the end frames forming a
part thereof,
wherein personnel platform-supporting ledgers are provided at a significant
safety distance below
the upper ends of the platform end frames so that a user is precluded from
positioning a
personnel platform at an elevated, unsafe position.
2. DESCRIPTION OF THE PRIOR ART
Scaffolding of various types has been provided in myriad forms over the years.
To be effective, construction site scaffolding must be relatively easy to
assemble and provide
a degree of flexibility so that scaffolding of various heights and widths can
be built. At the same
time, such scaffolding must be sturdy and structurally sound when constructed.
In recent years, safety regulations have mandated that personnel platforms
forming a part of scaffolding be located below the upper ends of the
scaffolding, so that
appropriate guardrails can be installed and are effective. As can be
appreciated, if a personnel
platform is located near the very top of a scaffolding unit, workers standing
on the platforms may
be subjected to significant falling hazard owing to the fact that inadequate
guardrails are present.
While these safety standards have been in place for several years, it is still
possible with existing scaffold designs to inadvertently or intentionally
construct a scaffold
assembly with improperly and unsafely positioned personnel platforms. This is
because of the
fact that prior scaffold frames have cross bars (often referred to as
"ledgers") close to or adjacent
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the upper end of the scaffold standards. In such a case, those constructing
the scaffolding, either
from expediency or lack of understanding of the safety rules, can place the
platforms in unsafe
elevated positions. Furthermore, during assembly of conventional scaffolding,
workers are often
required to stand on unguarded platforms while the next (upper) frame section
and other
scaffolding components are attached to the frame upon which the worker is
supported.
There is accordingly a need in the art for improved scaffolding which makes it
essentially impossible to place personnel platforms in elevated, unsafe
positions in violation of
existing safety standards.
SUMNIARY OF THE INVENTION
The present invention overcomes the problems outlined above, and provides a
scaffold assembly including a pair of end frames, each comprising a pair of
laterally spaced apart,
upright standards having opposed upper and lower ends, with a primary platform
ledger
extending between and interconnected with the standards. Each primary ledger
is located a
safety distance of at least about thirty (30) inches (more preferably from
about thirty-six (36) to
forty-two (42) inches) below the upper end of the corresponding standard. One
or more
personnel platforms span and are operatively supported by the end frame
ledgers. Additionally,
the end frames are free of platform ledgers within the safety distance above
the primary ledger,
so that no platform may be installed above the primary ledgers. In order to
erect a fi-ee-standing
scaffold, cross-tie structure is employed to interconnect the end frames.
Finally, the overall
scaffold assembly has a guardrail assembly extending between the end frames in
the safety
distance above the personnel platform.
The scaffold assemblies ofthe invention maybe provided in stacked
relationship,
i.e., two or more such assemblies may be placed one atop the other and
interconnected. To this
end, the scaffolds are designed for such vertical interconnection by means of
connection insert
pins at the upper ends of the corner standards, which telescope into the
tubular ends of the
standards of the scaffold assembly next above.
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In addition, the scaffold assemblies of the invention may be provided with
auxiliary features such as leveling units, end ladders, outriggers,
supplemental work platforms
and quick-connectors.
Another aspect of the present invention concerns scaffold end frame including
a
pair of laterally spaced apart, upright standards having opposed upper and
lower ends. The end
frame further includes a primary platform ledger extending between and being
interconnected
with the standards. The primary ledger is capable of supporting the end of a
personnel platform.
Moreover, the primary platform ledger is located a safety distance of at least
about thirty (30)
inches below each of the standard upper ends. The end frame is free of
platform ledgers within
the safety distance above the primary ledger.
Other aspects and advantages of the present invention will be apparent from
the
following detailed description of the preferred embodiments and the
accompanying drawing
figures.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
A preferred embodiment of the present invention is described in detail below
with
reference to the attached drawing Figures, wherein:
Fig. I is a perspective view of a scaffold assembly in accordance with the
invention;
Fig. 2 is a side elevational view ofthe scaffold assembly depicted in Fig. 1,
shown
during erection of another scaffold section atop the base scaffold assembly;
Fig. 3 is a perspective view of a scaffold assembly in accordance with the
invention, made up of two interconnected sections;
Fig. 4 is a side elevational view of a scaffold end frame in accordance with
the
invention;
Fig. 5 is a perspective view of another scaffold assembly in accordance with
the
invention, with the work scaffold assembly positioned atop a low-rise scaffold
base;
Fig. 6 is a perspective view of another type of scaffold end frame;
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Fig. 7 is a perspective view similar to that of Fig. 6 but showing another
type of
scaffold end frame; and
Fig. 8 is a perspective view of a multiple-tier scaffold assembly in
accordance
with the invention, equipped with ground-engaging outriggers and anuppermost
outrigger work
platform.
The drawing figures do not limit the present invention to the specific
embodiments disclosed and described herein. The drawings are not necessarily
to scale,
emphasis instead being placed upon clearly illustrating the principles of the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Turning now to the drawings, the scaffold assembly 10 selected for
illustration
in Fig. 1 broadly includes a pair of preconstructed end frames 12,14, a
personnel platform 16,
cross-tie assemblies 18,20, and guardrail assemblies 22,24. As shown, the
assembly 10 is a free-
standing unit for use on construction sites or in similar contexts.
In more detail, the end frames 12,14 in the depicted embodiment are mirror
images of each other. Thus, only the end frame 12 will be described in detail,
with the
understanding that the other end frame 14 is similarly constructed.
Furthermore, the same
reference numerals will be used to identify similar components of the end
frame 12 and 14.
As perhaps best shown in Fig. 4, the end frame 12 preferably includes a pair
of
upright standards 26,28, each having lower ends 26a,28a and upper ends
26b,28b. In the
preferred embodiment, the standards are formed of metal (e.g., steel or
Aluminum) and have a
circular, tubular configuration, although other suitable materials and
configurations are within
the ambit of the present invention. The standards 26,28 are preferably
provided with a series of
equally spaced apart accessory attachment holes 30 along the length thereof.
As will be
described, the attachment holes 30 removably receive connection pins so as to
permit attachment
of any variety of scaffolding accessories to the standard. Each standard is
also preferably
provided with three spaced apart inwardly projecting pin-type locks 32,33,34.
The overall end
frame 12 also has a primary ledger 36 which extends between and is connected
to the standards
26,28. Preferably, the ledger 36 is formed of the same material as the
standards 26,28 and
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similarly presents a circular tubular cross-section. The prefenred ledger 36
is integrally
connected to the standards 26,28 by suitable means, such as welding.
Moreover, the ledger 36 is located a safety distance 38 below the upper ends
26b,28b of the ledgers. This safety distance 38 is at least about thirty (30)
inches, and more
preferably is from about thirty-six (36) to forty-two (42) inches. The ledger
36 is additionally
supported by an end-mounted angular brace 40 secured to the underside of the
ledger 36 and to
the adjacent standard 26 at a point beneath the ledger. Similar to the
standards 26,28 and ledger
36, the brace 40 is preferably formed of cylindrical, tubular, metal bar.
However, if desired, the
ledger may alternatively be constructed in a manner similar to that disclosed
in copending U.S.
Patent Application Serial No. 10/950,113, filed September 24, 2004, entitled
WALKBOARD
LEDGER FOR SCAFFOLDING, published as Publication No. US 2005/0034922 Al.
The end frame 12 preferably also includes a ladder 44. The ladder 44 includes
first and second ladder side frames 46,48 as well as lateral rungs 50. As
illustrated, the lower
ladder side frarne 48 is secured to the underside of ledger 36 and extends
downwardly therefrom,
with the rungs 50 connected between the side &ame 48 and standard 28. The
upper ladder side
frame 46 is cantilever mounted through the medium of rungs 50 as shown, but
does not extend
to ledger 36. Those ordinarily skilled in the art will appreciate that this
configuration of the
upper ladder side frame 46 permits the platform 16 to be positioned on the
ledgers 36 within the
confines of the ladder 44. Although both end frames 12 and 14 have been shown
as being
provided with the ladder 44, in many instances only one of the end frames is
provided with a
ladder 44 to provide vertical access to the elevated platform(s) 16. It will
also be appreciated that
an angular brace is preferably not provided adjacent the standard 28, as the
ladder 44 sufficiently
interconnects the ledger 36 and standard 28 to provide the desired structural
reinforcement
therebetween.
In order to permit erection of a multiple-tier scaffold assembly, each of the
standards 26,28 receives a reduced diameter insert pin stub section 52,54
extending above the
associated upper ends 26b,28b. The and upper ladder side frame 46 also has a
reduced diameter
stub 56. The stacked fiames may be otherwise secured to one another if
desired.
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Returning to Fig. 1, it will be seen that each of the end frames includes a
pair of
screw-type leveling units 58, each being associated with a respective one of
the standards 26,28.
The units 58 are conventional and can be used to individually level each of
the standards as
required.
The platform (also known as a walkboard) 16 preferably includes elongated side
rails 60 as well as interconnected transverse end rails 62. The rails 60,62
support a substantially
flat walkway or platform pane164 to support users of the scaffold assembly.
The opposed ends
of the platform 16 are provided with a pair of spaced attachment hooks 66
configured to receive
the ledger 36 and thus support the platform in use. As noted previously, the
lower end of the
upper ladder side frames 46 are spaced slightly above the ledger 36; this
permits lateral shifting
of the platform 16 along the lengths of the ledgers 36 as necessary. The
platform 16 is preferably
constructed in a manner similar to that disclosed in U.S. Patent No.
6,223,857, issued May 1,
2001, entitled SCAFFOLDING PLATFORM.
However, other suitable walkboard designs are within the ainbit of the present
invention.
The cross-tie assemblies 18,20 each comprise apairofcrossed, angularlyoriented
tie bars 68,70 which are secured to the opposed standards 26,28 of the end
frames 12,14. As
illustrated, each of the tie bars 68,70 has endmost aperhired connectors
68a,70a which are
designed to receive the pin-type locks 33,34 of the standards. The assemblies
18,20, thus
operatively interconnect the end frames 12,14 so as to present a free-standing
scaffold. The locks
33,34 are conventional in design and serve to releasably lock the bars 68,70
to the standards
26,28 so as to prevent inadvertent removal after assembly.
Finally, the scaffold assembly 10 includes the guardrail assemblies 22,24 each
comprising a pair ofvertically spaced apart guardrail ties 72,74 having
apertured connection ends
72a,74a. These guardrail ties are attached to the upper pin-type locks 32,33
on the opposed
standards 26,28. The guard rails 22,24 provide safety to the scaffold user by
laterally
constraining any workers on the platform 16. The crossbar ties 68,70 and
guardrail ties 72,74
are preferably tubular cylindrical metal bars.
An important feature of the end frames 12,14, and thus of the complete
scaffold
assembly 10, is the provision of ledger 361ocated at the safety distance below
the upper ends
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26b,28b of the standards. 'Moreover, there is no ledger within the safety
distance, or closer to
the upper ends of the standards (it will be appreciated that low-strength
reinforcements could be
provided within the safety distance, but these would not be capable of
supporting a platform 16).
As such, the users of scaffold assembly 10 are necessarily provided with
lengths of standard
above the platform 16 which pennit installation of safety guardrails, and it
is impossible for such
users to inadvertently position a platform 16 within the safety distance.
Furthermore, as shown
in FIG. 2, during assembly of the scaffolding 10, the user stands safely on
the platform 16 as
he/she stacks end frames one on top of another, all the while being
safeguarded by the guardrails.
Fig. 6 illustrates another side frame 76 in accordance with the invention,
which
is identical with the side frame 12 of Fig. 4, save for the fact that the
ladder 44 is eliminated and
an angular brace 42 is provided between the ledger 36 and standard 28.
Therefore, no extended
discussion of this end frame 76 is needed, and the same reference numerals
used in the
description of the frame 12 are employed.
A still further end frame 78 is illustrated in Fig. 7. This end frame is
identical
with the end frame 76 of Fig. 6, except for the provision of a modified
ledger. Specifically, the
end frame 78 has a ledger 36 associated with longer reinforcing struts 40a,42a
which extend to
points below that of the corresponding struts 40,42. In addition, the ledger
36 is defined by
double transoms or bars 80 that are spaced vertically apart. Short connection
plates 82 extend
between the ledger bars 80, as shown. Here again, it will be seen that the
safety distance 38
between upper ledger 80 and the upper ends 26b,28b of the standards is
maintained. In use, the
platform 16 may be affixed to either of the ledger bars 80, but in either case
the important safety
distance 38 remains effective.
The scaffold assemblies of the invention can be constructed in a variety of
ways
to meet the needs of a construction site. For example (see Fig. 3), two (or
more) scaffold
assemblies 10, l 0a can be positioned one atop the other to create an overall
scaffold of increased
height. In Fig. 3, a lower assembly 10 is identical with that described
previously, and the upper
assembly l0a is supported on the assembly 10. This involves securing the lower
ends 26a,28a
of the upper standards to the insert pins 52,54 of the lower standards. As
illustrated in Fig. 2,
anupper end frame 14a is positioned on end frame 14 by telescoping the insert
pins 52,54 thereof
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into the lower tubular ends of the upper standards. When both of the upper end
frames 12a,14a
are so positioned, cross-tie assemblies and guardrail assemblies are
interconnected between the
upper standards to complete the construction. Fig. 3 also illustrates another
feature of the
invention, namely that the ledgers 36 are sufficient length to accommodate a
pair of side-by-side
platforms 16 as required.
Fig. 5 shows another scaffold assembly 84 made up of a scaffold assembly 10
positioned atop a low-rise height extender section 86. The latter is similar
to the scaffold
assembly 10, but is not designed to support a platform and is used simply to
create a higher
overall scaffold. To this end, the section 86 includes a pair of pre-
fabricated end frames 88,90,
each having upright standards 92,94 as well as uppermost cross brace 96. The
end frames 88,90
are interconnected by a cross-tie assemblies 98 as illustrated.
Finally, Fig. 8 depicts a two-tier scaffold assembly 100 made up of two
stacked
scaffold assemblies 102,104. The assembly 102,104 is made up ofend frames
106,108 including
upright standards 110,112 and ledgers 114 extending between and
interconnecting the standards.
The ledgers 114 are located the safety distance 38 from the upper ends of the
associated
standards, and support a pair of platforms 116. A cross-tie structure 118,120
is used to
interconnect the end frames 106,108, whereas guardrail assemblies 122,124 are
secured to the
standards within the safety distance. In this case, however, the end frames
106,108 have
secondary guardrail assemblies 126 which augment the assemblies 122,124. Each
of the end
guardrail assemblies 126 is in the form of a pair of vertically spaced apart,
laterally extending
rails 128,130 with interconnecting angular struts 132. The end guardrail
assemblies 126 are each
conveniently attached to the standards 110,112 by connection pins, each of
which is received in
an opening defined in the assembly 126 and an aligned attachment hole 133 of
the standard 110
or 112.
The lower assembly 102 is further supported by provision of four outriggers
134
respectively secured to each of the end frame standards. Each outrigger 134
includes an outboard
vertical leg 136 together with horizontal and angular connection struts
138,140 secured to leg
136 and clamped to the associated end frame standard via clamps 142.
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The upper scaffold assembly 104 is substantially identical with assembly 102
and
thus need not be described in detail. However, it will be observed that the
104 assembly has, in
lieu of the guardrail assembly 122, a secondary platform assembly 144. The
assembly 144
includes a personnel platform 146 as well as upwardly extending, endmost
standards 148,150
which support vertically spaced apart guardrail tie rods 152,154. The assembly
144 is secured
to upper scaffold assembly 104 by means of depending angular struts 156
attached to the
standards 110 via connection pins 158 (again, each being received in an
opening in the strut 156
and an aligned one of the attachment holes 133). Those ordinarily slcilled in
the art will
appreciate that the scaffolding is particularly useful in permitting various
scaffolding accessories
(e.g., the secondary guardrail assemblies 126, the secondary platform assembly
144, pulley-type
winches, etc.) to be simply and quickly attached to the standards. That is,
the equally spaced
apart attachment holes provide a system by which auxiliary scaffold components
can be
universally designed for uncomplicated association with the end frames.
The preferred forms ofthe invention described above are to be used as
illustration
only, and should not be utilized in a limiting sense in interpreting the scope
of the present
invention. Obvious modifications to the exemplary embodiments, as hereinabove
set forth,
could be readily made by those skilled in the art without departing from the
spirit of the present
invention.
The inventor hereby states his intent to rely on the Doctrine of Equivalents
to
determine and assess the reasonably fair scope of the present invention as
pertains to any
apparatus not materially departing from but outside the literal scope of the
invention as set forth
in the following claims.
Having thus described the preferred embodiments of the invention, what is
claimed as new and desired to be protected by Letters Patent includes the
following:
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