Note: Descriptions are shown in the official language in which they were submitted.
CA 02777793 2012-05-18
60813-402D
WORK PLATFORM FOR AN OVERHEAD CRANE
RELATED APPLICATION
[0001] This application is a divisional of Canadian Patent Application No.
2,537,014.
BACKGROUND OF THE INVENTION
[0002] The invention relates to overhead cranes, and more particularly, to the
performance of maintenance on overhead cranes.
[0003] It is often necessary to erect scaffolding and/or utilize lifting
equipment when
performing maintenance (e.g., repair, inspection, cleaning, modernization, and
the like) on
overhead cranes, and equipment and/or structures in the vicinity of overhead
cranes. Erection
of scaffolding and/or placement of lifting equipment can be time consuming and
dangerous
for maintenance personnel. This is especially prevalent in areas with limited
access, such as
containment buildings for atomic reactor power generating plants.
SUMMARY OF THE INVENTION
[00041 The invention provides work platforms for use in performing maintenance
while
supported on an overhead crane. The work platforms are particularly useful for
performing
maintenance on cranes located in areas where normal lifting equipment and/or
scaffolding
cannot easily access the crane. However, work platforms according to the
invention are also
useful for performing maintenance on equipment and/or structures in the
vicinity of overhead
cranes, and on. overhead cranes located in areas without accessibility
problems.
[00051 The work platform is hoisted for placement on the support structure of
the
overhead crane by at least one hoist apparatus of the overhead crane. When
positioned, the
work platform may be fully supported on the support structure of the overhead
crane so the
work platform can be utilized to perform an array of tasks, including, among
others, the
replacement or repair of portions of the overhead crane's hoist apparatus.
[00061 In one embodiment, the invention provides an overhead crane apparatus
including
an overhead crane and a work platform. The overhead crane includes a hoist
apparatus
1
CA 02777793 2012-05-18
60813-402D
operable to raise and lower a load, and a support structure that supports the
hoist apparatus
above the ground. The work platform is usable to perform maintenance while
supported on
the support structure. The work platform is capable of being lifted above the
ground by the
hoist apparatus. The work platform has a work surface sized to support at
least one
maintenance personnel for the performance of maintenance, and at least one
support member
that is connectable to the support structure when the work platform is
supported by the hoist
apparatus. The at least one support member is capable of supporting the work
platform on
the support structure independent of the hoist apparatus.
[0007] In another embodiment, the invention provides a method of performing
maintenance while supported on an overhead crane. The overhead crane includes
a hoist
apparatus operable to raise and lower a load, and a support structure that
supports the hoist
apparatus above the ground. The method includes providing a work platform,
lifting the
work platform above the ground using the hoist apparatus, and connecting the
work platform
to the support structure when the work platform is supported by the hoist
apparatus, such that
the support structure supports the work platform above the ground for the
performance of
maintenance. The work platform has a work surface sized to support at least
one
maintenance personnel for the performance of maintenance. The work platform is
capable of
being supported on the support structure independent of the hoist apparatus.
[0008] In yet another embodiment, the invention provides a method of
performing
maintenance while supported on a polar reactor overhead crane positioned in a
containment
building. The containment building includes an equipment hatch for moving
equipment in to
and out of the containment building. The polar reactor overhead crane includes
a hoist
apparatus operable to raise and lower a load, and a support structure that
supports the hoist
apparatus above the ground. The suppor t structure includes a pair of spaced
apart, generally
parallel girders, and a generally circular-rail that supports the girders. The
method includes
providing a work platform, moving the work platform through the equipment
hatch and into
the containment building, lifting the work platform above the ground using the
hoist
apparatus, and connecting the work platform to the girders when the work
platform is
supported by the hoist apparatus, such that the support structure supports the
work platform
above the ground for the performance of maintenance. The work platform has a
work surface
sized to support at least one maintenance personnel for the performance of
maintenance. The
2
CA 02777793 2012-05-18
' 60813-402D
work platform is capable of being supported on the support structure
independent of the hoist
apparatus.
[0009] in still another embodiment, the invention provides a work platform for
a crane
having a hoist supported by a girder. The work platform includes a
substantially horizontal
base sized to support at least one person, and a suspension support. The
suspension support
is coupled to the base and removably engageable with the girder to temporarily
couple the
base to the girder. A coupling is attached to the base to which the hoist is
connectable to
allow the hoist to raise and lower the platform to and from a position wherein
the suspension
support can engage the girder.
[0010] In another embodiment, the invention provides a jib crane comprising a
mast, a
first boom, and a second boom.. The first boom is pivotally coupled to an end
of the mast
and includes a first hoist movable on the first boom. The second boom is
movably coupled to
the first boom and includes a second hoist movable on the second boom.
[0011] - In yet another embodiment, the invention provides-an overhead crane
apparatus
comprising a hoist apparatus, a support structure, and a work platform. The
hoist apparatus is
operable to raise and lower a load and the support structure supports the
hoist apparatus
above the ground.- The work platform is usable to perform maintenance: while
supported on
the support structure and is capable of being lifted above the ground by the
hoist apparatus.
The work platform further includes at least one support member capable of
supporting the
work platform on the support structure independent of the hoist apparatus. The
support
member is movable along the support structure such that the work platform
moves along the
support structure.
[0012] In still another embodiment, the present invention includes an overhead
crane
apparatus comprising a hoist apparatus, a support structure, and a work
platform. The hoist
apparatus is operable to raise and lower a load and the support structure
supports the hoist
apparatus above the ground. The work platform has a base and is usable to
perform
maintenance while supported on the support, structure. The work platform is
capable of being
lifted above the ground by the hoist apparatus and includes at least one
support member that
is connectable to the support structure. The support member is capable of
supporting the
work platform on the support structure independent of the hoist apparatus. The
base of the
work platform is movable up and down along the support member.
3
CA 02777793 2012-05-18
60813-402D
[0013] In another embodiment, the present invention provides a crane apparatus
comprising a hoist apparatus, a support structure, and a work platform. The
hoist apparatus is
operable to raise and lower a load and the support structure comprises at
least two girders
spaced apart from each other and along which a trolley that supports the hoist
apparatus
above the ground moves. The work platform has a base and is usable to perform
maintenance while supported on the support structure. The work platform is
capable of being
lifted above the ground by the hoist apparatus and includes at least one
support member that
is connectable to the girders. The support member is capable of supporting the
work platform
on the girders independent of the hoist apparatus. The base of the work
platform is adjustable
to correspond to the distance between the girders.
[0014] In yet another embodiment, the invention provides an overhead crane
apparatus
comprising a hoist apparatus, a support structure, a work platform, and a
mast. The hoist
apparatus is operable to raise and lower a load and the support structure
supports the hoist
apparatus above the ground. The work platform has a base and is usable to
perform
maintenance while supported on the support structure. The work platform is
capable of being
lifted above the ground by the hoist apparatus and includes at least one
support member that
is connectable to the support structure. The support member is capable of
supporting the
work platform on the support structure independent of the hoist apparatus. The
mast extends
substantially perpendicularly from the base.
[00151 In still another embodiment, the invention provides a method of
implementing a
work platform for an overhead crane. The overhead crane includes a support
structure that
supports a hoist above the ground and the work platform includes a base and a
first support
member connected to the base and along which the base moves. The method
includes
-moving the work platform on a car into a space serviced by the overhead
crane, engaging the
first support member with the ground around the car, and moving the base of
the work
platform along the first support member to lift the work platform off of the
car.
4
CA 02777793 2012-05-18
60813-402D
In a further embodiment, the invention provides an overhead crane
apparatus comprising: a hoist apparatus operable to raise and lower a load; a
support
structure that supports the hoist apparatus above the ground; a work platform
usable
to perform maintenance while supported on the support structure, the work
platform
capable of being lifted above the ground by the hoist apparatus, the work
platform
having a work surface to support at least one maintenance personnel for the
performance of maintenance and at least one support member that is connectable
to
the support structure when the work platform is supported by the hoist
apparatus, the
at least one support member capable of supporting the work platform
independent of
the hoist apparatus; and wherein the at least one support member includes at
least
one wheel that rides on the support structure such that the work platform is
movable
along the support structure.
In a still further embodiment, the invention provides a method of
performing maintenance while supported on an overhead crane, the overhead
crane
including a hoist apparatus operable to raise and lower a load and a support
structure
that supports the hoist apparatus above the ground, the method comprising:
providing a work platform having a work surface to support at least one
maintenance
personnel for the performance of maintenance; lifting the work platform above
the
ground using the hoist apparatus; and connecting the work platform to the
support
structure when the work platform is supported by the hoist apparatus such that
the
support structure supports the work platform above the ground for the
performance of
maintenance, the work platform capable of being supported on the support
structure
independent of the hoist apparatus.
In a yet further embodiment, the invention provides a method of
performing maintenance while supported on a polar reactor overhead crane
positioned in a containment building, the containment building having an
equipment
hatch for moving equipment into and out of the containment building, the polar
reactor overhead crane including a hoist apparatus operable to raise and lower
a load
4a
CA 02777793 2012-05-18
60813-402D
and a support structure that supports the hoist apparatus above the ground,
the
support structure including a pair of spaced apart, generally parallel girders
and a
generally circular rail* that supports the girders, the method comprising:
providing a
work platform having a work surface to support at least one maintenance
personnel
for the performance of maintenance; moving the work platform through the
equipment
hatch and into the containment building; lifting the work platform above the
ground
using the hoist apparatus; and connecting the work platform to the girders
when the
work platform is supported by the hoist apparatus such that the support
structure .
supports the work platform above the ground for the performance of
maintenance,
the work platform capable of being supported on the support structure
independent of
the hoist apparatus.
In another embodiment, the invention provides a work platform for
crane having a hoist supported by a girder, the work platform comprising: a
substantially horizontal base to support at least one person; a suspension
support
coupled to the base and removably engageable with the girder to temporarily
couple the base to the girder; a coupling attached to the base and to which
the
hoist is connectable, thereby allowing the hoist to raise and lower the
platform to
and from a position wherein the suspension support can engage the girder.
In still another embodiment, the invention provides an overhead
crane apparatus comprising: a hoist apparatus operable to raise and lower a
load;
a support structure that supports the hoist apparatus above the ground; a work
platform usable to perform maintenance while supported on the support
structure,
the work platform capable of being lifted above the ground by the hoist
apparatus
and including at least one support member capable of supporting the work
platform on the support structure independent of the hoist apparatus, the at
least
one support member being movable along the support structure, such that the
work platform moves along the support structure; and wherein the at least one
support includes at least one wheel that rides on a track on the support
structure.
4b
CA 02777793 2012-05-18
60813-402D
In yet another embodiment, the invention provides an overhead
crane apparatus comprising: a hoist apparatus operable to raise and lower a
load;
a support structure that supports the hoist apparatus above the ground; a work
platform having a base and usable to perform maintenance while supported on
the
support structure, the work platform capable of being lifted above the ground
by
the hoist apparatus and including at least one support member that is
connectable
to the support structure, the at least one support member capable of
supporting
the work platform on the support structure independent of the hoist apparatus,
and
wherein the base of the work platform is movable up and down along the at
least
one support member; and wherein the at least one support member includes at
least one wheel that rides on a track on the support structure.
In a further embodiment, the invention provides an overhead crane
apparatus comprising: a hoist apparatus operable to raise and lower a load; a
support structure comprising at least two girders spaced apart from each other
and
along which a trolley that supports the hoist apparatus above the ground
moves; a
work platform having a base and usable to perform maintenance while supported
on the support structure, the work platform capable of being lifted above the
ground by the hoist apparatus and including at least one support member that
is
connectable to the girders, the at least one support member capable of
supporting
the work platform on the girders independent of the hoist apparatus, and
wherein
the base of the work platform is adjustable to correspond to the distance
between
the girders; and wherein the base includes a central portion connected to the
at
least one support member through a hydraulic connection, the hydraulic
connection being adjustable to move the support member closer to and farther
away from the central portion thereby adjusting the size of the base.
In a still further embodiment, the invention provides an overhead
crane apparatus comprising: a hoist apparatus operable to raise and lower a
load;
a support structure that supports the hoist apparatus above the ground moves;
4c
CA 02777793 2012-05-18
60813-402D
and a work platform having a base and usable to perform maintenance while
supported on the support structure, the work platform capable of being lifted
above
the ground by the hoist apparatus and including at least one support member
that
is connectable to the support structure, the at least one support member
capable
of supporting the work platform on the girders independent of the hoist
apparatus;
and a mast extending substantially perpendicularly from the base.
[0016] Further objects of the present invention together with the organization
and manner of operation thereof, will become apparent from the following
detailed
description of the invention when taken in conjunction with the accompanying
drawings wherein like elements have like numerals throughout the drawings.
4d
CA 02777793 2012-05-18
60813-402D
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The present invention is further described with reference to the
accompanying
drawings, which show an embodiment of the present invention. However, it
should be noted
that the invention as disclosed in the accompanying drawings is illustrated by
way of example
only. The various elements and combinations of elements described below and
illustrated in
the drawings can be' arranged and organized differently to result in
embodiments which are
still within the spirif and scope of the present invention. Also, it is
understood that the
phraseology and terminology used herein is for the purpose of description and
should not be.
regarded as limiting. The use of " including," "comprising," or "having" and
variations
thereof herein is meant to encompass the items listed thereafter and
equivalents thereof as
well as additional items. Unless specified or limited otherwise, the terms
"mounted,"
"connected," "supported," and "coupled" are used broadly and encompass both
direct and
indirect mountings, connections, supports, and couplings. Further, "connected"
and
"coupled" are not restricted to physical or mechanical connections or
couplings.
[0018] FIG. 1 illustrates a perspective view of a work platform for use in
performing
maintenance while supported by an overhead crane.
[0019] FIG. 2 illustrates an elevation view of the work platform of FIG; 1
moving
through an equipment hatch of a containment building.
[0020] FIG. 3 illustrates a sectional view of the work platform of FIG.1
showing the
work platform positioned in a hoisted position.
[0021] FIG. 4 illustrates a view similar to FIG. 3 showing the work platform
positioned in
a maintenance performing position.
[0022] FIG. 5 illustrates a top view of the work platform of FIG.1 positioned
in a
maintenance performing position.
[0023] FIG. 6 illustrates a side view of a.suspension support of the work
platform of FIG.
1.
[0024] FIG. 7 illustrates a rearview of the suspension support of FIG. 6.
CA 02777793 2012-05-18
60813-402D
[0025] FIG. 8 illustrates side view of the work platform of FIG. 1 with a jib
crane
attachment installed.
[0026] FIG. 9 illustrates a drum cradle attachment that can be installed on
the work
platform of FIG. 1.
[0027] FIG. 10 illustrates another. embodiment of a work platform for use in
performing
maintenance while supported by an overhead crane.
[00281 FIG. 11 illustrates the work platform of FIG. 10 on an equipment hatch
transfer
car.
[0029] FIG. 12 illustrates the work platform of FIG. 10 lifted off of the
transfer car of
FIG. 11 and standing on support members above the transfer car.
[0030] FIG. 13 illustrates a side view of the work platform of FIG. 10.
DETAILED DESCRIPTION
10031] The figures illustrate a work platform 10 according to one embodiment
of the
invention. The work platform 10 is illustrated and, described as being
utilized to perform
maintenance while supported on a polar reactor overhead crane 14 (FIG. 3). A
polar reactor
overhead crane is disclosed in each of U.S. Patent Nos.' 3,960,242 and
5,706,736. It should
be understood that the work platform 10.of the present invention is capable of
use in
performing maintenance while supported on other overhead cranes, and the
overhead crane
14 is merely shown and described as one such example.
[0032] The overhead crane 14 includes hoist apparatus 18 (FIG. 8), and a pair
of spaced
apart, generally parallel girders or bridge cross-members 22 (FIGS. 3-5). With
reference to
FIG. 3, trucks 23 mounted at opposite ends of the girders 22 include drive
wheels 24
rotatably mounted for engagement with a circular rail 25. The trucks 23 may
also include
non-driven or idler wheels 27 rotatably mounted for engagement with the rail
25. The rail 25
is mounted on suitable foundation means. The trucks 23, drive wheels 24, rail
25, and idler
wheels 27 are schematically illustrated in FIG. 3 and may be sized differently
and/or
positioned alternatively with respect to the girders 22 in actual
constructions. Engagement of
6
CA 02777793 2012-05-18
60813-402D
.the drive and-idler wheels 24 and 27 with the rail 25 supports the. crane 14
and permits travel
of the crane 14 along the rail 25. Movement of the hoist apparatus 18 relative
to the girders
22 in combination with movement of the girders 22 along the rail 25 allows the
hoist
apparatus 18 to access all areas within the containment building in which the
crane 14 is
operating. In other embodiments, the hoist apparatus 18 may be fixed relative
to the girders
22 and/or the girders 22 may be fixed relative to the rail 25.
[0033] With reference to FIG. 8, each hoist apparatus 18 is adapted to be
supported on
the girders 22 for movement relative to the girders 22. More specifically,
each hoist
apparatus 18 includes a trolley or frame 26 that is supported for travel on
tracks or rails 30 by
wheel assemblies 34. The rails 30 are mounted on the girders 22 of the crane
14. The hoist
apparatus 18 also includes a hoist drum 38 mounted on the frame 26 for
rotation about a
drum axis. A hoist rope 42 (FIGS. 3 and 4) is wound around the drum 38 such
that the rope
42 winds on to and-off of the drum 38 in response to rotation of the drum 38
in opposite
wind-on and wind-off directions, respectively.
[00341 The hoist apparatus 18 also includes a load engaging mechanism 46
connected to
the rope 42. The load engaging mechanism 46 includes a 'bottom block through
which the
rope 42 is reeved, and a hook depending from the bottom block. As is known in
the art, the
load engaging mechanism 46 moves upward when the rope 42 winds on to the drum
38, and
moves downward when the rope 42 winds off of the drum 38. The hoist apparatus
18 also
include a'motor 50 that is mounted on the frame 26: The motor 50 is connected
to the drum
38 for selectively rotating the drum 38 in the opposite wind-on and wind-off
directions. The
hoist apparatus 18 as thus far described are conventional and need not be
described in greater
detail. The crane 14 is illustrated as including two hoist apparatus 18. In
other embodiments,
the crane 14 may include fewer or more hoist apparatus 18.
[0035] The work platform 10 is a structure that is temporarily attached to the
girders 22
of the crane 14. The work platform 10 functions as a work area for maintenance
personnel
that are performing maintenance on the crane 14 and/or on other equipment
and/or structure
in the vicinity of the crane 14. The work platform 10 also functions as an
installation tool in
the performance of such maintenance. The work platform 10 is particularly
useful for
performing maintenance on the crane 14 because it is located in an area (i.e.,
a containment
building) where normal lifting equipment and/or scaffolding cannot easily
access the crane
7
CA 02777793 2012-05-18
60813-402D
14. In other embodiments, Work platforms according to the invention are-also
useful in
performing maintenance in areas without accessibility problems.
[0036] The work platform 10 includes, a generally horizontal work surface 54
(FIG. 5)
sized to support at least one maintenance personnel for performing
maintenance. The
illustrated work surface 54 is sized to support up to four maintenance
personnel. In other
constructions, the work surface 54 may be smaller or larger. The illustrated
work surface 54
is coated with an anti=skid paint.
[0037] With reference to FIG. 5, a mast 58 extends through the center of the
work surface
54. Guide rollers 60 allow the mast 58-to move vertically relative to the work
surface 54.
The illustrated mast. 58 is constructed in two portions to ease transport of
the work platform
10. The upper portion of the mast'58 (FIG. 8) includes a rotating assembly
58a. A number of
different attachments are connectable to the mast 58 for use in performing
maintenance.
[0038] FIGS. I and 9 illustrate a drum cradle attachment 62. The drum cradle
attachment
62 is sized to handle hoist drum assemblies 64 (e.g., the drum 38, the rope 42
wrapped on the
drum. 38, gearing of the drum 38, and the like). The drum cradle attachment 62
is fully
rotatable when positioned on the rotating assembly 58a. In one construction,
the rotating
assembly 58a includes two sets of thrust bearings to provide such rotation.
The drum cradle
attachment 62 also includes a longitudinal adjustment feature to ease
placement of the drum
cradle attachment 62 with respect to a hoist drum assembly 64, and to allow
movement of the
hoist drum assembly 64.relative to the mast 58 when the hoist drum assembly 64
is supported
on the drum cradle attachment 62. The drum cradle attachment 62 may be
alternatively
constructed in other embodiments.
[0039] FIG. 8 illustrates a jib crane attachment 66. The jib crane attachment
66 is
movable between a locked position, as shown in dotted lines on FIG. 8, and a
fully extended
position, as shown in solid lines on FIG. 8. The jib crane attachment 66
includes a two beam
design that eases movement of the jib crane attachment 66 relative to the
crane 14. The lower
beam or boom 66a includes. a two-ton capacity hook 66b mounted on rollers. The
upper
beam or boom 66c includes a. one-ton capacity chain hoist 66d mounted on
rollers. The
illustrated jib crane attachment 66 can extend up to approximately eighteen
feet from the
mast 58. The jib crane attachment 66 may be alternatively constructed in other
embodiments
8
CA 02777793 2012-05-18
60813-402D
and may be connected, permanently or temporarily, to a portion of the overhead
crane 14,.
such as the girders 22 or trolley 26.
[0040] In other embodiments, a worker basket attachment that supports movement
of
maintenance personnel relative to the work surface 54 maybe connected to the
mast 58. The
worker basket attachment may include both vertical and horizontal movement
relative to the
mast 58. In constructions where the worker basket attachment is utilized to
perform
maintenance on equipment and/or structure in the vicinity of the crane 14
(e.g., sprayers
located on the ceiling of the containment building), the crane 14 may be moved
to reposition
the worker basket attachment relative to the equipment and/or structure. In
yet other
embodiments, other types of attachments may be'attached to the mast 58 to
perform or assist
in the performance of maintenance.
[00411 With reference to FIGS. I and 8, the lower portion of the mast 58
includes a
sheave assembly 58b. Rope 70 extending from a hoist unit 74 is reeved around,
redirection
sheaves 76, through the sheavd assembly-58b, and to a dead ended assembly 78
mounted on
the underside of the work platform 10. The illustrated dead end assembly 78
includes two
dead ends mounted to a load bar. The hoist unit 74 is mounted below the work
surface 54 in
a hoist unit compartment 82.. The hoist unit 74 includes a hoist drum 86
having the rope 70
wound there around in a double reeved configuration such that the rope 70
winds on to and
off of the drum 86 in response to rotation of the drum 86 in opposite wind-on
and wind-off
directions, respectively. The hoist unit 74 also includes a motor 90 that
selectively rotates the
drum 86 in the opposite wind-on and wind-off directions. The mast 58 moves
upward when
the rope 42 winds onto the drum 38, and moves downward when the-rope 42 winds
off of the
drum 38. The illustrated 'mast 58 provides fourteen feet of vertical travel at
ten feet-per-
minute, and includes eleven tons of lift capacity.
[0042] The mast may.alternatively be a telescoping mast 258, as shown in FIG.
10. The
telescoping mast 258 includes multiple sections (3, as illustrated in FIG. 10)
that nest within
one another and hydraulically extend.relative to each other to provide
extension of the mast
without requiring the mast to extend below the base of the work platform, as
is the case in the
embodiment of the work platform 10, shown in FIGS. 1 through 8. The mast 58
may be
alternatively constructed in other embodiments.
9
CA 02777793 2012-05-18
60813-402D
[0043]. With reference to FIG. 1, the work platform 10 is equipped'with lift-
off handrails
94. The hand rails 94 may include multiple removable segments to allow
equipment or other
objects to pass. In other embodiments, the handrail 94 may include a chain
gate to allow
equipment or other objects to pass. Further, the hand rail 94 may include a
removable barrier
to prevent objects from falling from the work platform 10. In some
constructions, the
removable barrier is see-through (e.g., acrylic).
[00441 With reference to FIGS. 1 and 3-4, the work platform 10 includes wing
plates 98
extending outward from the sides of the work surface 54. A wing plate 102 is
also positioned
on a portion of the handrail 94. The wing plates 102 prevent objects from
falling from the
work platform 10. The illustrated wing plates 98. are pivotable, and the wing
plate 102 is
fixed. In other embodiments, the work platform 10 may include fewer-or more
wing plates
98, 102, or other types of object deflectors.
[00451 With reference to FIGS. 3-5, the work platform 10 includes hook
linkages 106.
Each hook linkage 106 is mounted below the work surface 54 in a hook linkage
compartment
110. The hook linkages 106 fold away into respective hook linkage compartments
110 when
not in use, and extend from the hook linkage compartments 110 for engagement
by the load
engaging device 46 of a respective hoist apparatus 18. The work platform 10
includes two
sets of hook linkages 106. In other embodiments, the work platform 10 may
include fewer or
more sets of hook linkages 106, or other types of hook attachments.
[00461 The work surface 54 includes a plurality of trap. doors to.
compartments (e.g., the
hoist unit compartment 82, the-hook linkage compartments 110) located below
the work
surface 54. The compartments are utilized to provide access to equipment
(e.g., the hoist unit
74), and to stow equipment, tools, and the like. With reference to FIGS. 3-5,
the work
platform 10 also includes load engaging device compartments 114. The load
engaging device
compartments 114 are each sized to receive the load engaging device 46 of a
respective hoist
apparatus 18. Each load engaging device compartment 114 can be utilized to
support the
load engaging device 46 for reeving and unreeving. Utilization of the
compartments provides
an unobstructed work surface 54 for the maintenance personnel that includes an
optimized
amount of floor space.
[0047] With reference to FIGS. 1 and 6-7, the work platform 10 includes four
suspension
supports 118. Each suspension support 118 is secured to a bracket 122 mounted
on the work
CA 02777793 2012-05-18
60813-402D
surface 54. using two pins, Each suspension support 118 is.movable between a
folded
position, as shown in FIG. 2 and as shown in dotted lines on FIG. 5, a
hoisting position, as
shown in FIG. 3 and as shown in dotted lines on FIG. 6, and a maintenance
performing
position, as shown in solid lines on FIGS. 1.and.4-8. A top portion 118a of
each suspension
support.118 includes a pivotable head having a profile that allows the hoist
apparatus 18 to
pass over the top (i.e., the suspension supports 118 do not interfere with the
interaction
between the hoist apparatus 18 and the rails 30). Each suspension support 118
includes a
horizontal stabilizer 118b, a vertical stabilizer 118c, and a biasing member
118d. The
vertical stabilizer 118c pivots the top portion 118a relative to the remainder
of the suspension
support 118. The biasing member 118d includes a spring that biases the top
portion 118a
against the vertical stabilizer 118c. Contact pads 11 8e on the top portion
118a and the
horizontal stabilizer 118b may include an' elastomer or other non-abrasive
material to prevent
metal-to-metal contact and paint scraping on the girders 22. As best shown in
FIG. 7, each
suspension support 118 also includes a set of hand grips 118f. In other
embodiments, the
work platform 10 may include other types of support members that connect the
work
platform 10 to the. girders 22. In one such embodiment, the support member(s)
may be
mounted on the rails 30 for movement of the work platform 10 relative to the
girders 10. A.
.come-along or other suitable means may be.utilized to move the work platform
10 relative to.
the crane 14. .
[0048] As best seen in FIG. 3, the work platform 10 has a width corresponding
to the
distance between the girders 22. That is, the work platform 10 is sized so
that the suspension
supports 118 are appropriately spaced from one another to properly engage the
girders 22.
'As shown in FIG. 10, another embodiment of 'it work platform 200 according to
the present
invention includes a base 202 whose width can be changed to accommodate
various spacings
between. girders 222.
[00491 The work platform 200 includes a central portion 204 that is connected
to
suspension supports 218. The central portion 204 may be connected to the
suspension
supports 218 through a connecting spacer plate 206 that is sized for the
particular girder
spread the work platform 200 is to be used on. Depending on the size of the
spacer plate 206,
the suspension supports 218 will be closer to or farther away from the central
portion 204 of
the work platform 200, thereby changing the overall width of the work platform
200 to
correspond to the particular girder spread.
11
CA 02777793 2012-05-18
60813-402D
[0050] Alternatively, the central portion 204 may be connected to the
suspension supports
218 using a hydraulic connection 208, as also shown in FIG. 10. Actuation of
the hydraulic
connection 208 moves the suspension supports 218 closer to and farther away
from the
central portion 204. The hydraulic connection 208 provides infinite
adjustability of the
distance between the suspension supports 218 and the central portion 204
without the need
for custom manufacturing spacer plates 206 for the particular girder spread on
which the
work platform 200 is to be used.
[00511 In some embodiments, the work platform 10 or 200 may include bottom
support
members such as retractable outrigger supports that extend from the work
platform 10 to
contact the bottom side of the girders 22. The bottom support members act as a
positive stop
when hoisting the work platform 10 to the girders 22. Bottom support members
are
particularly useful when hoisting a work platform 10 using a single hoist
apparatus 18. The
hoist apparatus 18 can hoist the work platform 10 until the bottom support
members are tight
against the underside of the girders 22, thereby providing a stable work
surface 54 until the
suspension supports 118 are in place.
[0052) The work-platform. 10 is designed as a fluid tight structure to prevent
fluids (e.g.,
water, oil, lubricants, and the like) utilized while performing maintenance
from falling
through the work platform 10 and to the floor below. The work platform 10 is
also designed
to prevent objects (e.g.,. tools, equipment, and the like)_utilized while
performing maintenance
from falling through the work platform 10 and to the floor below. Further, the
work platform
is designed to utilize removable pins and quick connections for ease of the
assembly of
removable and/or collapsible components (e.g., handrails 94, suspensions
supports 118) of
the work platform 10.. The pins may include grab handles for ease of removal,
and tie chains
secured to the work platform 10 to prevent dropping of the pins from the work
platform 10.
The removable pins may be stowed in a compartment under the work surface 54
when not
being used.
[0053) The work platform 10 includes electrical service to allow for
utilization of power
tools and welding equipment. In one construction, power is connected to the
work platform
10 by means of a cable reel, tag line festoon, or the like. A circuit breaker
may be located on
the work platform 10 that includes control of all power to the hoist unit 74
and the receptacles
located on the work platform 10.
12
CA 02777793 2012-05-18
60813-402D
[00541 The work platform. 10 includes.a control for the hoist unit 74 that
allows the
maintenance personnel to raise and lower the mast 58 relative to the work
surface 54. In one
construction, the hoist unit control includes an isolation transformer and is
located in a
compartment under the work surface 54 near the mast 58. A mast control
pushbutton station
123 (schematically illustrated in FIG. 4), with mast-on/off and mast
raise/lower controls, is
electrically connected to the hoist unit controL The mast control pushbutton
station 123 may
include a-cord or wireless connection that allows for operation of the mast 58
from any
location on the work surface 54. The mast control pushbutton station 123 may
also include
attachment controls (e.g., jib crane attachment controls, drum cradle
attachment controls,
worker basket attachment controls). In other constructions, the attachments
maybe
alternatively controlled.
[0055] The work platform 10 also includes a crane control pushbutton station
124
(schematically illustrated in FIG. 4) that allows for remote operation of the
crane 14. The
crane control pushbutton station 124 is electrically connected to the crane
controls. The
crane control pushbutton station 124 includes crane onlofi:, hoist-one-
raise/lower and
forward/reverse, hoist-two raise/lower and forward/reverse, hoist-auxiliary
raise/Iower and
forward/reverse, and girders forward/reverse controls. The crane control
pushbutton station
124 may include a cord or wireless connection that allows for operation of the
crane 14 from
any location on the work surface 54. In one embodiment, the normal crane
controls are
locked-out to only allow operation of the crane 14 using-the crane control
pushbutton station
124 while the workplatform 10 is being utilized to-perform maintenance.
Pendant controls
224, as shown in FIG..10, may also be utilized, providing a worker with wired
control of the
work platform 200 from a remote location, such as the ground, a girder 222,
etc.
[0056] With reference to FIG. 2, the work platform 10 is designed to fit
through an
equipment hatch 126 of a containment building 130. The illustrated work
platform 10 is
approximately twelve feet wide, twenty-four feet long, four feet deep, and
weights
approximately twenty-one tons. The equipment hatch 126 is approximately
fourteen feet, six
inches in diameter. The work platform 10 is brought into the containment
building 130 in a
collapsed state on an equipment hatch transfer car 134. The transfer car 134
is supported on a
pair of temporary rails 138 that extend into the containment building 130.
10057] When the work platform 10 is inside the containment building 130, the
removable
and/or collapsible components (e.g., handrails 94, suspensions supports 118)
of the work
13
CA 02777793 2012-05-18
60813-402D
platform 10 are assembled to configure the work platform 10 in an uncollapsed
state. .
Configuration of the work platform 10 in the uncollapsed state may occur
before and/or after
the work platform is connected to the girders 22.
[00581 In the embodiment illustrated in FIGS. 1 through 8, a respective hoist
apparatus
18 (e.g., an auxiliary hoist apparatus of the crane 14) is utilized to lift
the suspension supports
118 from the folded position to the hoisting position. The illustrated
suspension supports 118
weigh approximately 400 pounds. The suspension supports 118 maybe locked in
the
hoisting position using the pins. As illustrated in FIG. 6, the hoisting
position is
approximately eighty percent of the maintenance.performing position. Placement
of the
suspension supports 118 in the hoisting position allows a maintenance
personnel to moved
the suspension supports 118 the remainder of the way.to the maintenance
performing position
using the hand grips 118 The suspension supports 118 are moved to the
maintenance
performing position when the work platform 10 is positioned in a hoisted
position, as
illustrated in FIG. 3.
[00591 According to the work platform 200, as shown in FIG. 10, the suspension
supports
218 move into position hydraulically (Le., they hydraulically move from their
folded
positions, to their hoisting positions, to their maintenance performing
positions), eliminating
the need to use the hoist apparatus 18 and/or manual assistance to move the
suspension
supports 218 into position. Shoes 210 may or may not be manually adjusted for
the particular
girder angle and girder geometry. Further, the suspension supports,218 are
constructed to
include first portions 214 that move within second portions 216 so that the
height of the base
portion 202 of the work platform 200 can be adjusted relativeto the girders
222. The base
portion 202 of the work platform 200 is coupled to the second portions 216 of
the suspension
supports 218. Therefore, the base portion 202 moves up and down when the first
portions
214 move within the second portions 216 of the supports 218.
[0060] As shown in FIGS. 11 and 12, the movement of the first portions 214
through the
second portions 216 of the suspension supports 218 can be utilized to lift the
work platform
200 off of the equipment hatch transfer car 134 that maybe used to move the
work platform
200 into a containment building. When the work platform 200 is positioned
within the
building and it is desired to move the equipment hatch transfer car out from
below the work
platform 200, the base portion 202 of the work platform 200 can be lifted off
the equipment
hatch transfer car by moving the first portions 214 of the suspension supports
218 through the
14
CA 02777793 2012-05-18
60813-402D
second portions 216 until the first. portions 214 engage the ground beneath
the equipment
hatch transfer car. Once the first portions 214 have engaged the ground,
further movement of
the first portions 214 through the second portions 216' will cause the base
portion 202 of the
work platform 200 to raise off of the equipment hatch transfer car 134, as
shown if FIG. 12.
The equipment hatch transfer car 134 can then be moved on rails 138 out froiii
under the base
portion 202 of the work platform 200 while the base portion 202 is "standing"
above the
equipment hatch transfer car 134 on the first portions 214 of the suspension
supports 218, as
shown in FIG. 12.
[0061] In addition to the base 202 of the work platform 200 being movable
relative to the
girders 222 through the movement of the first.portions 214 of the suspension
supports 218
relative to the second portions 216, the entire work platform 200 is movable
along the girders
222. Referring particularly to Figs. 10 and 13, the shoes 210 of the
suspension supports 218
engage the girders 222 to secure the work platform 200 to the girders 222. As
best seen in
FIG. 10, the shoes 210 include first portions 212 and second portions 213. The
first portions
212 engage the girders 222 and hold the work platform 200 in a fixed position
relative to the
girders 222. However, if it is desired that the entire work platform 200 be
movable along the
girders 222, the second. portions 213 of the shoes 210 can be rotated over the
top of the first
portions 212 so that wheels 215 (best seen in FIG. 13) engage rails 226 that
run along the
tops of the girders 222. The rails 226 may be the same rails on which the
trolley of the crane
rides. With second portions 213 of the shoes 210 rotated into position so that
the wheels 215
engage the rails 226, as shown in FIG. 13, the first portions 212 of the
shoes.210 can be lifted
off of, and thereby' disengaged from, the girders 222, so that the work
platform 200 is free to
roll along the tops of the girders 222 on the wheels 215. Some or all of the
wheels 215 can be
driven for automatic movement of the work platform 200 along the girders 222.
Alternatively, the wheels can simply be mounted for free rotation requiring an
external force
(e.g., a manual force) to move the work platform 200 along the girders 222.
[0062] Referring back to FIGS. 1 through 8, when the work platform 10 is ready
to be
hoisted, the load engaging devices 46 'of the hoist apparatus 18 are lowered
and connected to
the hook linkages 106. -When each load engaging device 46 is securely
connected, the motors
50 are driven to turn the drums 38 in the wind-on direction. The work platform
10 is hoisted
up to the girders 22 (i.e., to the hoisted position). Hoisting the work
platform 10 for
placement on the crane 14 using the crane 14 eliminates the need for other
lifting equipment.
CA 02777793 2012-05-18
60813-402D
In other constructions, the work platform 10 maybe hoisted to the girders 22
using fewer or
more hoist apparatus 18.
[0063] While the work platform 10 is.still supported by the hoist apparatus
18, the
suspension supports 118 are connected to the girders 22 (i.e., moved to the
maintenance
performing position). The horizontal stabilizers 11 8b are adjusted to center
the work surface
54 between the girders 22. The vertical stabilizers 118c are adjusted to level
the work surface
54. The suspension supports 118 may be utilized to fully support the work
platform 10. In
other embodiments, the load engaging devices 46 may remain connected to the
hook linkages
106 to provide additional support. Once the work platform 10 is stabilized,
the wing plates
98 are pivoted into position against the girders 22 (FIG. 3-5) to prevent
objects from falling
between the work platform 10 and the girders 22.
[00641 When the work platform 10 is in the maintenance performing position, as
illustrated in FIG. 4, the maintenance personnel can begin to perform the
necessary
maintenance.
[00651 In one embodiment, maintenance may include the replacement'of the hoist
drum
assembly 64. The drum cradle attachment 62 is connected to the mast 58 and
moved into
position under the hoist drum assembly 64. The crane control pushbutton
station maybe
utilized to position the hoist apparatus 18 above the mast 58. Further, the
longitudinal
adjustment feature of the drum cradle attachment 62 may be utilized to
position the drum
cradle attachment 62 directly below the hoist drum assembly 64. The mast 58 is
then raised
vertically and the hoist dram assembly 64 is lifted from its bearing seats.
When the hoist
drum assembly64 is clear of the remaining components of the hoist apparatus
18, the crane
control pushbutton station 124 is utilized to move the remaining components of
the hoist
apparatus 1 S. The drum cradle attachment 62 is then rotated ninety degrees so
the drum axis
is parallel to the girders 22. The mast 58 is lowered to bring the drum cradle
attachment 62
near the work surface 54. The hoist drum assembly 64 can then be lowered off
the work
platform 10 using an existing hoist apparatus 18 or, alternatively, a lifting
devices that is
temporarily supported by the crane 14 or structure adjacent to the crane 14.
[0066] In another embodiment, maintenance may include the replacement of the
motor 50
or other components on the hoist apparatus 18. The jib crane attachment 66 is
connected to
the mast 58 and moved into position above the hoist apparatus 18. Either the
hook 66b or the
16
CA 02777793 2012-05-18
60813-402D
chain hoist 66d may be utilized to lift the motor 50 from the frame 26 to the
work surface 54.
Once the motor 54 is positioned on the work surface 54, the motor 50 can then
be lowered off
the work platform 54 using an existing hoist apparatus 18 or, alternatively, a
lifting device
that is temporarily supported by the crane 14 or structure adjacent to the
crane 14. In some
embodiments, the jib crane attachment 66 may be designed to lower objects to
the ground. In
yet other embodiments, the work platform 10 may include other lifting devices
capable of
moving objects from the work surface 54 to the ground.
[0067] The work platform 10 provides a convenient means to work high in the
air, while
virtually eliminating the possibility of objects and/or fluids falling to the
ground. The work
platform 10 includes the ability to lift heavy pieces onto and off of the
crane 14. The work
platform 10 also allows for the operation of power tools and welding
equipment.
Additionally, the crane 14 can be remotely operated from the work platform 10,
and the work-
platform 10 does not interfere with operation of the crane 14.
[0068] The embodiments described above and illustrated in the figures are
presented by
way of example only and are not intended as a limitation upon the concepts and
principles of
the present invention. As such, it will be appreciated by one having ordinary
skill in the art
that various changes in the elements and their configuration and arrangement
are possible
without departing from the spirit and scope of the present invention as set
forth in the
appended claims.
17
