Note: Descriptions are shown in the official language in which they were submitted.
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BRACE FOR STEP LADDER
FIELD
[0001] This specification relates to step ladders and to accessories
for step ladders.
BACKGROUND
[0002] US Patent Number 5,715,909, Stepladder Including a Bracing
Shelf,
describes a stepladder with a pivoting bracing shelf. The bracing shelf acts
as a
conventional pivoting shelf and a bracing mechanism to prevent accidental
closing of the
stepladder when the shelf is in the bracing position.
[0003] US Patent Number 6,116,379, Ladder Stabilizing Cross Brace,
describes two
types of ladder stabilizing system. In one type of system, the ladder has a
shelf or
triangulated structure that is hinged to one side of the ladder and can be
connected to the
other side of the ladder. In the second type of system, there is a folding
cross brace with a
folding compound hinge that extends, when unfolded, diagonally across the
ladder.
INTRODUCTION:
[0004] The following introduction is intended to introduce the reader
to the detailed
description to follow and not to limit or define any claimed invention.
[0005] A typical step ladder has two sections hinged together near their
upper ends.
Each section has two legs. When the ladder is opened, two struts unfold to
provide a
horizontal linkage that prevents the ladder from opening beyond a selected
angle. When the
ladder is opened, the top of the ladder may provide a narrow platform.
[0006] The inventor has observed that these ladders suffer from a
number of
deficiencies. For example, the folding struts are typically slender and so
step ladders are not
rigid in use, particularly in the case of large ladders. Further, the struts
are easily bent. For
example, it often happens during construction work that a ladder falls over
sideways and its
struts become distorted. Even after only one fall, the four legs of the ladder
might no longer
contact a flat floor at the same time.
[0007] Conventional step ladders also encourage workers to leave tools on
the
narrow platform at the top of the ladder. In large ladders, this platform can
be above the
heads of people working around the ladder. When the ladder is bumped, or moved
by
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another person who cannot see that there are tools on the platform, a tool can
fall and break
the tool or injure a person.
[0008] This specification describes a brace for use with a step
ladder. The brace has
a platform that resists shear forces in the plane of the platform. The brace
also has two
runners, one located on each of two opposed sides of the platform. The runners
are
configured to fit over the unfolded struts of a step ladder. Optionally, the
platform may have
a movable shelf, for example a sliding shelf.
[0009] In a method of bracing a step ladder, a brace as described
above is placed
with its runners fitting over, and resting on, the struts of the ladder. The
brace stabilizes the
ladder and helps prevent injury to the struts if the ladder falls over.
Optionally, the runners
may also force distorted struts into a better alignment. Optionally, the
platform may also
provide one or more surfaces for supporting tools.
[0010] This specification also describes a tool shelf for use at the
top of a step ladder.
BRIEF DESCRIPTION OF THE FIGURES
[0011] Figure 1 shows a side view of a brace.
[0012] Figure 2 shows a side view of the brace of Figure 1 and a
ladder, wherein the
brace is on its way to being installed on the ladder.
[0013] Figure 3 shows a top view of a tool shelf for use on the top
of a ladder.
[0014] Figure 4 shows a top view of the brace of Figure 1 with an optional
sliding
shelf extended.
[0015] Figure 5 shows an end view of the brace of Figure 1.
[0016] Figure 6 shows a close up isometric view of part of the brace
of Figure 1
installed on the struts of a ladder.
[0017] Figures 7 and 8 are photographs of another brace.
DETAILED DESCRIPTION
[0018] Figures 1, 2,4, 5, 6, 7 and 8 show a brace 10 for stabilizing
a step ladder 12.
The brace 10 has a platform 14 and two runners 16. The brace 10 is not
permanently
attached to the ladder 12. To use the brace 10, the ladder 12 is opened and
the brace 10 is
placed over the struts 18, alternatively called straps or arms, which prevent
the two sections
of the ladder 12 from spreading apart. The struts 18 slide into slots 20 in
the runners 16. In
most cases, the struts 18 cannot be bent into an inverted V shape and lowering
the brace 10
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causes the struts 18 to slide into slots 20. In other cases, the struts 18 can
be pushed into
the slots 20 or the two sections of the ladder 12 can be pulled apart while
lowering the brace
over the struts 18.
[0019] The slot 20 provides an interference fit over each strut 18.
However, a tight fit
5 is not required. For example, the slots 20 may be about 1 to 5 mm wider
than the struts 18.
A central section of the slots 20 may be widened further to make room for any
pins,
abutments or other elements at the joint between two struts 18. The slots 20
are preferably
at least 10 mm deeper than the struts 18.
[0020] Optionally, the brace 10 may have one or more fasteners or
latches 22 to
10 retain the struts 18 within the slots 20. For example, as shown in
Figures 5 and 6, pins or
bolts 24 may be placed across the width of the slot 20 below the struts 18. In
many cases,
these fasteners 22 are not required. However, very tall step ladders in
particular are safer
when the fasteners 22 are used.
[0021] The platform 14 may be continuous or discontinuous. When a
discontinuous
platform 14 is used, the platform 14 preferably has a lattice-like structure
so that the platform
14 can still be used to hold tools or other items. However, an open truss-like
structure may
also be used. The platform 14 should resist shearing in the plane of the
platform 14. The
platform 14 should tend to keep the runners 16 parallel to each other and
spaced apart from
each other.
[0022] The runners 16 may also be continuous or discontinuous. If a runner
16 is
discontinuous, it preferably has at least one section around a pivot between
the struts 18 and
two distal sections away from this pivot point. The length of the runners 16
is preferably at
least 80 percent of the length of the unfolded struts 18.
[0023] The brace 10 shown in Figures 1, 2, 4 and 6 has an optional
shelf 30. The
shelf 30 is preferably movable relative to the platform 14 so that the shelf
30 can be retracted
to make the brace 10 more compact at times. For example, the shelf 30 may fold
or slide
relative to the platform 14. The shelf 30 shown sits on top of the platform 14
and has two
opposed edges held within a pair of track runners 32. This shelf 30 can slide
to the left or
right to extend from either side of the platform 14. Bolt holes 34 in the
corners of the sliding
shelf correspond with two holes 36 on the centreline of the platform in either
extended
position. A fastener or pin can be placed through these holes 34, 36 to retain
the shelf 30 in
either extended position.
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[0024] While the platform 14 can be used to hold tools or a can of
paint etc. directly,
the shelf 30 increases the useful area of the platform 14. Since the brace 10
is low relative
to the total height of the ladder 12, it provides a more stable location than
a shelf near the top
of a ladder for tools and other items. The stable location allows large items,
for example
ceiling fixtures, to be safely placed on the brace. Items on the brace 10 are
also more visible
to others than when a shelf is provided at the top of a ladder. Even with a
relatively large
ladder 12, a person can reach up to the brace 10 to place items for use when
on the ladder
12. However, the brace 10 still allows a person to retrieve items temporarily
placed on the
brace 10 without stepping completely on or off of the ladder 12, which can be
dangerous and
time consuming.
[0025] For example, when installing fixtures such as a fan or light
on a tall ceiling, a
step ladder 12 that is more than eight feet tall may be required. It is
dangerous to place a
fixture on the top of such a ladder 12 before climbing on to the ladder 12. It
is also
dangerous to step onto a tall ladder 12 while holding a large fixture. The
inventor has found
that placing the fixture on the brace 10, and then stepping on to the ladder
12, and then
picking up the fixture while climbing the ladder 12 provides a safer
operation. Optionally,
when using very tall ladders 12, for example more than 12 feet high, a
concrete block or
other weight can be lifted onto the brace 10 from the ground and helps to
further stabilize the
ladder 12.
[0026] Optionally, the platform 14 or any shelf 30 attached to the platform
14 may
have a raised lip 38 around its perimeter to resist tools from rolling or
sliding off the shelf 30.
The lip 38 may protrude by 5 mm or more from the upper surface of the platform
14 or shelf
30. Optional holes or slots drilled through the platform 14 or shelf 30 can be
used to hold
one or more powered or unpowered hand tools, the end of an extension cord, or
other useful
items. An optional circular indentation 40 or cut-out in the upper surface of
the shelf or
platform can be used to help hold a can of paint or another liquid.
[0027] The brace 10 shown in Figures 7 and 8 was designed to fit one
size of
Featherlite TM ladder 12. These ladders 12 are available at many retail
outlets. The
dimensions of the brace 10 can be adjusted to fit other commercially available
ladders 12.
The brace 10 shown was constructed of wood but other materials, such as
plastic, can also
be used. The brace 10 has a sliding shelf 30 but may be made without a shelf
30.
[0028] The top of Figure 2 and Figure 3 show another shelf 50. This
shelf 50 can be
attached to the top of a ladder 12 by fasteners placed through two or more
bolt holes 52 in
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the shelf 50 and corresponding holes in the top of the ladder. These bolt
holes 52 may be
located in the shelf 50 to correspond with exiting holes in the top of a
ladder 12. Alternatively,
corresponding holes may be drilled into the top of the ladder 12. The
fasteners may be, for
example, flat head screws. The shelf 50 may be left in place or removed when
not in use.
[0029] The shelf 50 of Figure 3 is not meant for standing on but can be
used to hold
tools. The shelf 50 preferably has a raised lip 54 around its perimeter to
resist tools from
rolling or sliding off the shelf 50. The lip 54 may protrude by 5 mm or more
from the upper
surface of the shelf 50. Optional holes or slots drilled through the shelf can
be used to hold
one or more powered or unpowered hand tools, the end of an extension cord, or
other useful
items. An optional circular indentation 56 or cut-out in the upper surface of
the shelf can be
used to help hold a can of paint or another liquid. However, as discussed
above, large items
or items that could be bumped off of a shelf 50 are preferably kept on the
brace 10 rather
than at the top of a ladder 12.
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