U.S. patent application number 11/257495 was filed with the patent office on 2006-04-27 for scaffolding structure.
Invention is credited to Wilf Vaillancourt.
Application Number | 20060086568 11/257495 |
Document ID | / |
Family ID | 36242684 |
Filed Date | 2006-04-27 |
United States Patent
Application |
20060086568 |
Kind Code |
A1 |
Vaillancourt; Wilf |
April 27, 2006 |
Scaffolding structure
Abstract
A scaffolding structure for mounting to a supporting structure
such as a bridge includes a track fixable to the supporting
structure, and a frame. The frame and track are movable relative to
one another, and the frame is also movable relative to the
supporting structure between a first position and a second
position. In the first position, the track supports the frame, and
the track is supported by the supporting structure, so that when
the track is fixed to the supporting structure, the frame can
advance along the track and therefore along the supporting
structure. In the second position, the frame is supported by the
supporting structure and the track is supported by the frame, so
that the track can advance along the supporting structure. By
alternately advancing the frame and the track, the scaffolding
structure can advance along the entire length of the supporting
structure.
Inventors: |
Vaillancourt; Wilf; (Sault
Ste. Marie, CA) |
Correspondence
Address: |
BERESKIN AND PARR
40 KING STREET WEST
BOX 401
TORONTO
ON
M5H 3Y2
CA
|
Family ID: |
36242684 |
Appl. No.: |
11/257495 |
Filed: |
October 25, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60621057 |
Oct 25, 2004 |
|
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|
Current U.S.
Class: |
182/36 |
Current CPC
Class: |
E04G 3/30 20130101; E04G
3/24 20130101; E01D 19/106 20130101 |
Class at
Publication: |
182/036 |
International
Class: |
E04G 3/28 20060101
E04G003/28 |
Claims
1. A scaffolding apparatus providing access to a structure,
comprising: a frame, the frame comprising two side supports and a
cross-member connected between the side supports, the frame
supporting a worker platorm; at least one coupling mechanism
coupled to each side support for coupling the frame to a supporting
structure; each coupling mechanism including a rail assembly, each
rail assembly extending in a longitudinal direction and being
selectively securable to the supporting structure, rail assembly
having a housing shaped to retain a roller member secured to the
frame therewithin and to permit movement of the track and the at
least one foot relative to one another in the longitudinal
direction of the supporting structure; an actuator secured to the
frame and adapted to selectively move the coupling mechanism
between a first position wherein the frame is movable relative to
the rail assembly and the supporting structure in the longitudinal
direction, and a second position wherein the frame is fixed
relative to the supporting structure and the rail assemblies are
movable relative to the frame and the supporting structure in the
longitudinal direction.
2. The scaffolding structure of claim 1, wherein the first position
defines a lowered position in which each rail assembly bears
against the support structure, and the weight of the frame bears
against each rail assembly, and wherein the second position defines
a raised position in which each rail assembly is raised clear of
the support structure, and the weight of the frame bears against
the support structure.
3. The scaffolding structure of claim 2, wherein each coupling
mechanism comprises at least one jack, the jacks adapted to engage
the supporting structure and elevate the frame to move the coupling
mechanism from the first position to the second position.
4. The scaffolding structure of claim 3, wherein each housing
defines a roller retaining channel having a lower channel surface
for bearing against the roller member when the coupling mechanism
is in the first position.
5. The scaffolding structure of claim 4, wherein each retaining
chamber has an upper channel surface for bearing against the roller
member when the frame is in the second position.
6. A scaffolding structure comprising: a frame; a track, the track
being selectively fixable to a supporting structure having a
longitudinal direction, the track being movably mountable to the
frame; a mechanism secured to the frame and adapted to selectively
move the frame between a first position wherein the frame is
movable relative to the track and the supporting structure in the
longitudinal direction of the supporting structure, and a second
position wherein the frame is fixed relative to the supporting
structure and the track is movable relative to the frame and the
supporting structure in the longitudinal direction of the
supporting structure when not secured thereto.
7. The scaffolding structure of claim 6, wherein the first position
is a non-elevated position relative to the supporting structure,
and wherein the second position is an elevated position relative to
the supporting structure.
8. The scaffolding structure of claim 7, wherein the mechanism
comprises a plurality of jacks, and wherein the jacks are adapted
to engage the supporting structure and elevate the frame into the
second position.
9. The scaffolding structure of claim 8, wherein the frame
comprises at least one foot, and wherein the track comprises at
least one rail assembly, and wherein each at least one rail
assembly comprises a housing shaped to receive and movably retain
therewithin a corresponding at least one foot.
10. The scaffolding structure of claim 9, wherein each housing has
an interior surface or surfaces, and wherein each at least one foot
comprises a member or members for rollably engaging the interior
surface or surfaces of the corresponding housing within which the
foot is retained.
11. The scaffolding structure of claim 10, wherein each housing has
an upper interior surface and a lower interior surface, and wherein
each foot comprises a wheel or wheels, and wherein when the frame
is in the first position, the wheel or wheels support the frame and
are rollably disposed on the lower interior surface of the
corresponding housing, and wherein when the frame is in the second
position, each at least one rail assembly is supported by its upper
interior surface, the upper interior surface resting rollably on
the wheel or wheels of the corresponding foot.
12. A displaceable scaffolding apparatus, comprising: a) a frame
supporting a worker platform; b) a coupling mechanism connected to
the frame for coupling the frame to a pair of beams of a structure,
the coupling mechanism movable between a first position and a
second position; c) the coupling mechanism including a track
fixable relative to the beams and along which the frame can be
advanced when the coupling mechanism is in the first position; d)
the frame being fixable relative to the beams for advancing the
track relative to the frame when the coupling mechanism is in the
second position.
13. The apparatus of claim 12 wherein the coupling mechanism
comprises actuators for moving the coupling mechanism between the
first and second positions, the actuators having a body portion
fixed to the frame and an extension portion displaceable relative
to the body portion and adapted to engage the beam.
14. The apparatus of claim 13 wherein the track is raised clear of
the beam when the coupling mechanism is in the second position.
15. The apparatus of claim 14 wherein the coupling mechanism
comprises a plurality of rollers rotatable about a roller axis, the
roller axis being fixed relative to the frame, and the rollers
being coupled to the track.
16. The apparatus of claim 15 wherein the track comprises rail
elements having a roller retaining channel along which the rollers
travel for coupling the frame to the track, the roller retaining
channel having a channel height that extends between a lower
channel surface and an upper channel surface.
17. The apparatus of claim 16 wherein the channel height is greater
than the roller diameter by an amount defining a channel clearance,
and wherein the rollers engage the lower channel surface when the
coupling mechanism is in the first position, and engage the upper
channel surface when the coupling mechanism is in the second
position.
18. The apparatus of claim 17 wherein the total displacement of the
extension portion when moving the coupling mechanism between the
first and second positions is greater than channel clearance.
19. A method of providing worker access to a structure having
beams, comprising: a) providing a scaffold apparatus having a frame
supporting a worker platform and a coupling mechanism for coupling
the frame to the beam, the coupling mechanism including a track
displaceable relative to the frame; b) fixing the track to the beam
along a first selected beam segment; c) advancing the frame along
the track to adjust the position of the platform to facilitate
worker access to parts of the structure generally aligned with the
selected beam segment; d) fixing the frame to the beam with the
track clear of the beam; e) advancing the track relative to the
beam to a second selected beam segment adjacent the first selected
beam segment; and f) repeating step c) for the second selected beam
segment.
20. The method of claim 19 wherein the coupling mechanism includes
actuators movable between advanced and retracted positions, and
wherein step d) includes moving the actuator to the advanced
position.
Description
[0001] This application claims the benefit under 35 USC 119(e) of
U.S. Provisional Application No. 60/621,057, which was filed on
Oct. 25, 2004, and the entire contents of which are hereby
incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to scaffolding structures, and
particularly to scaffolding structures that are useful for the
maintenance and repair of bridges.
BACKGROUND OF THE INVENTION
[0003] It is well known that routine maintenance of load-bearing
structures such as bridges is necessary to remedy normal
deterioration and prevent the structures from becoming unsafe to
use. While it has been known to support scaffolding from the upper
beams of a bridge so that workers can access the sides of the
bridge to carry out maintenance, difficulties remain in advancing
the scaffolding along the length of the bridge.
[0004] A number of structures have been proposed for use in the
repair and maintenance of bridges.
[0005] U.S. Pat. No. 4,201,275 describes a method for refurbishing
and renovating large span overhead structures such as bridges.
Runway beams are suspended from the main ribs of the structure, and
working platforms are suspended from the runway beams. The runway
beams are displaceable from the main ribs, and the working
platforms are displaceable along the runway beams. The overhead
structure is treated by alternately advancing the working platforms
along the runway beams and the runway beams relative to the
structure.
[0006] U.S. Pat. No. 5,634,528 describes a workstation that can be
advanced across a bridge by using a plurality of slotted box beams.
The box beams are temporarily fastened to the bridge girders, and
wheeled posts that support scaffolding are received within the box
beams. The scaffolding can be rolled along the box beams, and new
box beams can be placed down as the scaffolding advances, while
those that have been passed over can be taken up and moved forward
to a new position.
[0007] There remains a need, however, for an improved scaffolding
structure for use with supporting structures such as bridges, which
does not require the use of multiple track elements to advance to
scaffolding structure along the bridge.
SUMMARY OF THE INVENTION
[0008] In one aspect, the present invention is directed to a
scaffolding structure. The scaffolding structure comprises a frame
having two side supports and a cross-member connected between the
side supports, and at least two feet, at least one foot supporting
each side support. The scaffolding structure further comprises at
least two rail assemblies, each rail assembly being selectively
securable to a supporting structure having a longitudinal
direction. Each rail assembly has a housing shaped to retain a
corresponding at least one of the at least two feet therewithin and
to permit movement of the track and the at least one foot relative
to one another in the longitudinal direction of the supporting
structure. The scaffolding structure further comprises a mechanism
secured to the frame and adapted to selectively move the frame
between a first position wherein the frame is movable relative to
the rail assemblies and the supporting structure in the
longitudinal direction thereof, and a second position wherein the
frame is fixed relative to the supporting structure and the rail
assemblies are movable relative to the frame and the supporting
structure in the longitudinal direction of the supporting structure
when not secured thereto.
[0009] Preferably, the first position of the frame is a
non-elevated position relative to the supporting structure, and the
second position is an elevated position relative to the supporting
structure. The mechanism preferably comprises a plurality of jacks,
at least one jack being associated with each foot, wherein the
jacks are adapted to engage the supporting structure and elevate
the frame into the second position.
[0010] Each housing has an interior surface or surfaces, and each
at least one foot comprises a member or members for rollably
engaging the interior surface or surfaces of the corresponding
housing within which the foot is retained. Preferably, each housing
has an upper interior surface and a lower interior surface, each
foot comprises a wheel or wheels, and when the frame is in the
first position, the wheel or wheels support the frame and are
rollably disposed on the lower interior surface of the
corresponding housing, and when the frame is in the second
position, each at least one rail assembly is supported by its upper
interior surface, the upper interior surface resting rollably on
the wheel or wheels of the corresponding foot.
[0011] In another aspect, the present invention is directed to a
scaffolding structure comprising a frame and a track that is
selectively fixable to a supporting structure having a longitudinal
direction, the track being movably mountable to the frame. The
scaffolding structure further comprises a mechanism secured to the
frame and adapted to selectively move the frame between a first
position wherein the frame is movable relative to the track and the
supporting structure in the longitudinal direction of the
supporting structure, and a second position wherein the frame is
fixed relative to the supporting structure and the track is movable
relative to the frame and the supporting structure in the
longitudinal direction of the supporting structure when not secured
thereto.
[0012] In yet another aspect, the present invention is directed to
a scaffolding structure for mounting to a supporting structure. The
scaffolding structure comprises a track having a longitudinal
direction and being selectively fixable to the supporting
structure, and a frame, the frame being movably mountable to the
track so that the frame and the track are movable relative to one
another in the longitudinal direction of the track, the frame being
movable relative to the supporting structure between a first
position wherein the frame is supported by the track and the track
is supported by the supporting structure, and a second position
wherein the frame is supported by the supporting structure and the
track is supported by the frame.
[0013] In another aspect, the present invention provides a method
of providing worker access to a structure having beams, the method
includingteh steps of a) providing a scaffold apparatus having a
frame supporting a worker platform and a coupling mechanism for
coupling the frame to the beam, the coupling mechanism including a
track displaceable relative to the frame; b) fixing the track to
the beam along a first selected beam segment; c) advancing the
frame along the track to adjust the position of the platform to
facilitate worker access to parts of the structure generally
aligned with the selected beam segment; d) fixing the frame to the
beam with the track clear of the beam; e) advancing the track
relative to the beam to a second selected beam segment adjacent the
first selected beam segment; and f) repeating step c) for the
second selected beam segment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a side view of a bridge having an embodiment of a
scaffolding structure according to the present invention positioned
thereon;
[0015] FIG. 2 is an end view of a bridge having an embodiment of a
scaffolding structure according to the present invention positioned
thereon;
[0016] FIG. 3 is an end cross sectional view of an aspect of a
first embodiment of a scaffolding structure according to the
present invention positioned on a bridge, with the scaffolding
structure shown in a first position;
[0017] FIG. 4 is an end cross sectional view of an aspect of a
first embodiment of a scaffolding structure according to the
present invention positioned on a bridge, with the scaffolding
structure shown in a second position;
[0018] FIG. 5a is a side view of a portion of a bridge having an
embodiment of a scaffolding structure according to the present
invention positioned thereon, with the scaffolding structure shown
in a first position at a first longitudinal location on the
bridge;
[0019] FIG. 5b is a side view of a portion of a bridge having an
embodiment of a scaffolding structure according to the present
invention positioned thereon, with the scaffolding structure shown
in a first position at a second longitudinal location on the
bridge;
[0020] FIG. 5c is a side view of a portion of a bridge having an
embodiment of a scaffolding structure according to the present
invention positioned thereon, with the scaffolding structure shown
in a second position at the second longitudinal location on the
bridge;
[0021] FIG. 5d is a side view of a portion of a bridge having an
embodiment of a scaffolding structure according to the present
invention positioned thereon, with the scaffolding structure shown
in a second position at the second longitudinal location on the
bridge;
[0022] FIG. 5e is a side view of a portion of a bridge having an
embodiment of a scaffolding structure according to the present
invention positioned thereon, with the scaffolding structure shown
in a first position at the second longitudinal location on the
bridge;
[0023] FIG. 6 is an end cross sectional view of an aspect of a
second embodiment of a scaffolding structure according to the
present invention, with the scaffolding structure shown in a first
position;
[0024] FIG. 7 is an end cross sectional view of an aspect of a
third embodiment of a scaffolding structure according to the
present invention positioned on a bridge, with the scaffolding
structure shown in a first position;
[0025] FIG. 8 is an end cross sectional view of an aspect of a
third embodiment of a scaffolding structure according to the
present invention positioned on a bridge, with the scaffolding
structure shown in a second position.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Referring now to FIGS. 1 and 2, a portion of a structure 10
is shown. The structure 10 can be in the form of a bridge, and can
have a framework including support columns 12, lower longitudinal
beams 14, upper longitudinal beams 16, vertical posts 18, and
reinforcing struts 20. Referring specifically to FIG. 2, the bridge
10 also includes upper and lower transverse beams 22, and
additional cross struts 24. A road surface 26 is supported on the
lower longitudinal beams 14 and transverse beams 22. One skilled in
the art will appreciate that the bridge 10 is exemplary only, and
is described herein solely for the purposes of providing a detailed
description of a preferred embodiment of the present invention.
Accordingly, it will be appreciated that the present invention may
be used with any suitable type of structure or bridge. The bridge
10 serves as a supporting structure for a scaffolding apparatus
according to the present invention.
[0027] Still referring to FIGS. 1 and 2, a scaffolding apparatus
according to one embodiment of the present invention is shown
generally at 100. In the particular embodiment shown, the
scaffolding apparatus 100 comprises a frame 102 having two side
supports 104 and a cross member 106. A platform or basket (also
called a spider) 108 can be suspended from the cross member 106 by
means of cables 110. The platform 108 can support workers to carry
out maintenance on the bridge 10. As can be seen best in FIG. 2,
the cross member 106 preferably extends beyond the side supports
104 to facilitate maintenance of exterior portions of the bridge
10. Thus, the spider 108 can be suspended on either the outside or
the inside of the bridge, depending on the particular maintenance
work being done.
[0028] As shown in FIG. 1, the side supports 104 are, in the
illustrated embodiment, generally in the form of an A-frame having
diagonally downwardly extending legs. A coupling mechanism 112 is
provided at the lower end of each leg of the of the side supports
104 for coupling the frame 102 to the beam 16 of the bridge 10. The
coupling mechanisms 112 are also generally referred to as feet 112
herein. The coupling mechanism 112 includes a track 111 and
actuators 115, described in greater detail subsequently herein.
[0029] It can be seen that one advantage of the configuration used
in accordance with the present invention is that maintenance
operations can be carried out without obstructing vehicle traffic
across the bridge 10. Even when the spider 108 must be positioned
inside the bridge and close to the road surface 26, such operations
can be performed during periods of low traffic, and the spider 108
can be temporarily raised out of the way when a vehicle approaches.
The scaffolding structure 100 may be lifted into an initial
placement atop the bridge 10 by a mobile crane positioned
temporarily on the road surface 26. The spider 108 can be lowered
to the level of the road surface to provide for entry and exit of
the crew.
[0030] As can be seen in FIG. 1, the bridge 10 has a longitudinal
direction A. The beams 16 and the track 111 have longitudinal axes
that are, when the scaffolding apparatus 100 is supported on the
bridge 10, generally parallel to the longitudinal direction A. As
described in greater detail subsequently herein, when the track 111
and the frame 102 are coupled together and to the beam 16 in
accordance with the present invention, the frame 102 and the track
111 are movable relative to one another in the longitudinal
direction of the track 111. The track 111 can include two
transversely spaced rail assemblies 114 along which the frame 102
can be displaced.
[0031] Now referring to FIGS. 3 and 4, one preferred embodiment of
the coupling mechanism 112 for coupling the scaffold apparatus 100
to the beams 16 is shown in greater detail. The coupling mechanism
112 provides an interconnection between the frame 102, rail
assemblies 114, and the beams 16. In the embodiment shown, the
upper horizontal beam 16 is in the form of an I-beam having a
vertical portion (or web) 116, an upper horizontal (flange) portion
118, and a lower horizontal (flange) portion 120. Portions of the
bridge 10 other than the upper horizontal beam 16 have been omitted
for clarity in some Figures.
[0032] In a preferred embodiment, each rail assembly 114 includes a
lower track plate (also called bearing plate) 122 and a housing
(also called retainer channel) 124. The track plate 122 can include
a vertically protruding guide 123 running along its length. In the
particular embodiment shown, the housing 124 includes side plates
126 extending upwardly from transversely opposed sides of the
bearing plate 122, and top plates 128 directed inwardly and
extending towards each other from respective upper ends of the side
plates.
[0033] The two top plates 128 are vertically spaced apart from the
bearing plate 122 to define a retaining channel height 129 (FIG.
3). The top plates 128 have inner edges 128a that are spaced
laterally apart to define an elongated slot 130 that extends along
the length of the rail assembly 114. The opposing surfaces of the
top plates 128 and bearing plate 122 define upper and lower channel
surfaces 125 and 127, respectively.
[0034] Fastening brackets 132 can be disposed on the lower track
plate 122 to facilitate fixing the rail assembly 114 to the upper
horizontal beam 16. For example, in FIG. 3 the rail assembly 114 is
fastened to the upper horizontal beam 16 by means of a cable 134
wrapped around the beam 16 and connected at either end to the
brackets 132. Alternatively (not shown), the upper horizontal beam
16 and the rail assembly 14 can be provided with respective ones of
a pair of engagement elements adapted to interengage for fixing the
rail assembly to the beam. The track plate 122 and housing 124 can
be made from any suitable material, for example steel or
aluminum.
[0035] The foot 112 can include a main support leg 140 that, in the
embodiment shown, forms a contiguous part of the A-frame side
support 104. An axle 142 is rotatably mounted at the end of the
main support 140, and wheels (also referred to as rollers) 144 are
fixedly mounted to the axle 142. Thus, the wheels 144 can rotate
relative to the main support 140 about an axis that is, in the
illustrated embodiment, fixed relative to the frame 102. One
skilled in the art will realize that the axle 142 could be fixedly
mounted to the support leg 140, and the wheels 144 rotatably
mounted to the axle 142, without affecting the operation of the
present invention. Similarly, both the axle 142 and wheels 144
could be rotatably mounted. The rollers 144 have a diameter 145
that is less than the channel height 129. The difference between
the roller diameter 145 and the channel height 129 defines a
channel clearance 147.
[0036] When the frame 102 and track assembly 111 are mounted to one
another, the wheels 144 fit within and are surrounded by the
housing 124 of the rail assembly 114, as shown in FIGS. 3 and 4.
The main support leg 140 projects generally upwardly through the
elongated slot 130. The guide 123 assists in maintaining alignment
of the wheels 144 within the housing 124. Once the wheeled portion
of the foot 112 is positioned within the rail assembly 114, the
ends of the rail assembly are preferably sealed by an end plate
(not shown) to prevent the foot 112 from moving beyond the ends of
the rail assemblies 114.
[0037] The foot 112 includes actuators 115 as mentioned previously.
The actuators 115 can generally include a body portion and an
extension portion that is movable relative to the body portion for
moving the frame 102 relative to the beam 16 when in use. The
actuators 115 can be in the form of jacks 150, having body portions
156 secured to the frame 102, and extension portions 158
telescopically housed within the body portions 156.
[0038] The jacks can be hydraulic actuators, the body portions 156
providing a cylinder or chamber and the extension portion 158
including a piston slidable within the chamber 156. The chamber 156
can be fixed to the frame 102, and in the illustrated embodiment,
is secured to the main support leg 140 of the frame 102 by means of
struts 152 and additional reinforcing members 154.
[0039] Alternatively, one or more of the jacks 150 can be, for
example, but not limited to, pneumatic actuators, or mechanical
screw-type jacks. In the particular embodiment shown, the extension
members 158 include a rod member 160 slidable within the chamber
156, and an engagement member 162 fixed to the rod member 160 and
adapted to engage a portion of the beam 16. In the embodiment
illustrated, the rod member is oriented generally vertically, and
the engagement member 162 extends laterally inwardly for engaging
an upper surface of the lower flange 120 of the beam 16. Each foot
112 can include one or more jacks 150. In the embodiment
illustrated, each foot 112 is provided with four jacks 150.
[0040] The coupling mechanism 112 of the present invention is
movable between first and second positions. The first position
corresponds to a state in which the rails 114 of the track 111 are
fixed relative to the beam 16 (i.e. held stationary), and the frame
102 is displaceable relative to the rails for advancing the
platform 108 therealong. The second position corresponds to a state
in which the frame is fixed relative to the beam 16 (i.e. held
stationary), and the rails 114 of the track 111 are displaceable
relative to the frame 102 for advancing the track 111 relative to
the beam 16. In general terms, this allows a relatively short
length of track 111 to be "walked" along the relatively longer
length of beam 16. Between "steps" (i.e. between repositioning of
the track 111), workers occupying the platform 108 can carry out
the required work and reposition the platform 108 along the
stationary track 111 as required.
[0041] Further details of the operation of one embodiment of the
scaffolding apparatus 100 according to the present invention will
now be described.
[0042] FIG. 3 shows a coupling mechanism 112 in the first position.
The track 111, and in particular the lower track plate 122, rests
on the upper horizontal portion 118 of the I-beam 16 along a
selected segment of the length thereof. The weight of frame 102
bears against the rail assembly 114, so that the track can be
fastened securely to the upper horizontal beam 16 by cable 134.
Thus, the rail assembly 114 will be fixed relative to the upper
horizontal beam 16, and therefore also relative to the bridge
10.
[0043] The jacks 150 are in a retracted position, so that the
engaging members 158, and in particular the horizontal portions 162
thereof, do not contact the lower horizontal portion 120 of the
upper horizontal beam 16. The weight of the frame 102 is supported,
by way of main support leg 140, on the wheels 144, which rest on
the lower channel surface 125. In this configuration, therefore,
the frame 102 is supported by the rail assemblies 114, and the rail
assemblies 114 are in turn supported by the bridge 10. When work is
being carried out, the frame 102 can be course be fixed relative to
the rail assemblies 114 and bridge 10. For this purpose, the
horizontal portions 162 of the engaging members 162 can be provided
with vice members (also called clamping elements) 164 that can be
moved inwardly to contact and apply pressure to the vertical
portion 116 of the upper horizontal beam 16 so as to fix the frame
102 in position. When it is desired to advance the frame 102 along
the rail assemblies 114, the vice members 164 may be retracted. The
vice members 164 may be mechanical, hydraulic or pneumatic in the
embodiment illustrated, the vice members 164 are mechanical and are
of the screw type, as shown in FIGS. 3 and 4.
[0044] When the vice members 116 have been retracted, the frame 102
will be movable relative to the rail assemblies 114 and the bridge
10 in the longitudinal direction of the bridge 10. Thus, by way of
the wheels 144 rolling along the lower channel surface 127, the
frame 102 can advance along the rail assemblies 114 until it
reaches the ends thereof. The ends are preferably capped to prevent
inadvertent overtravel of the rollers 144 out of the channel 124,
and to keep the rail assemblies 114 and frame 102 unreleasably
coupled together.
[0045] Once the frame 102 has reached the ends of the rail
assemblies 114, the rail assembly can be shuttled into position
along a subsequent selected segment of the length of the beam 16 in
accordance with the present invention. This can be performed by
moving the coupling apparatus into the second position. Prior to
doing so, the cables 134 (if used) can be removed from the rail
assemblies 114. Also, for safety reasons, the spider 108 can be
moved to an elevated position near to or immediately below the
cross member 106.
[0046] FIG. 4 shows the relative locations of the coupling
apparatus 112, rail assembly 114 and upper horizontal beam 16 when
the coupling apparatus 102 is in the second position. When the
frame 102 is in the second position, the jacks 150 are extended so
that the engaging members 158, and in particular the horizontal
portions 162 thereof, contact the lower horizontal portion 120 of
the upper horizontal beam 16. This raises the leg 140, and
therefore the frame 102, into an elevated position relative to the
upper horizontal beam 16 and therefore also relative to the bridge
10.
[0047] As the leg 140 is raised by the jacks 150, the wheels 144
are raised off the lower channel surface 127 and contact the upper
channel surface 125 of the roller retaining channel 124. As the leg
140 continues to be lifted upward by the jacks 150, the rail
assembly 114 will be lifted off the upper horizontal portion 118 of
the upper horizontal beam 16 so that it is supported by (i.e.
suspended from) the wheels 144. Thus, the frame 102 is supported by
the bridge 10 (by way of the jacks 150 engaging the upper
horizontal beam 16) and the rail assemblies 114 are supported by
the frame 102 (by way of the wheels 144). Furthermore, because of
the weight of the frame 102 and the frictional forces acting
between the engagement members 158 and the lower horizontal portion
120 of the upper horizontal beam 16, the frame 102 will be fixed
relative to the bridge 10. To further fix the frame 102 relative to
the bridge 10, once the jacks 150 have fully extended, the vice
members 164 can again be brought into contact with the vertical web
116 of the upper horizontal beam 16. The rail assemblies 114 are
movable relative to the frame 102 (and therefore relative to the
bridge 10) in the longitudinal direction of the bridge 10. In
particular, the wheels 144 act as rollers to allow the rail
assemblies 114 to be moved relative to the frame 102 and bridge
10.
[0048] Once the rail assemblies have been advanced into position
along a new segment of the beam 16, the jacks 150 can be retracted
so that the frame 102 (and therefore the rail assemblies 114) are
lowered. Once the rail assemblies 114 have been lowered into
contact with the upper horizontal beam 16 in their new position,
they can be refastened to the upper horizontal beam 16 by way of
the cables 134.
[0049] Now referring to FIGS. 5a through 5e, the operational
sequence of a maintenance operation, using an embodiment of the
scaffolding structure 100 according to the present invention, is
shown. In FIGS. 5a to 5e, certain features, such as the spider 108
and portions of the bridge 10, have been omitted for the sake of
clarity. In FIGS. 5a to 5e, the longitudinal direction A is the
same as the longitudinal direction A of the bridge 10 shown in FIG.
1.
[0050] Referring first to FIG. 5a, the frame 102 is in the first
position, corresponding to that shown in FIG. 3. Specifically, the
frame is supported by the rail assemblies 114, and the rail
assemblies 114 are supported by the upper horizontal beam 16. By
rolling engagement of the rollers 144 along the lower channel
surface 127 (FIG. 3), the frame 102 can be advanced along the rail
assemblies 114 in the longitudinal direction A until it reaches an
end 136 of the rail assemblies 114, as shown in FIG. 5b.
[0051] With reference now to FIG. 5c, once the frame 102 has
reached the end of the rail assemblies 114, the cables 134 can be
unfastened and the coupling mechanism 112 can be moved into the
second position as shown in FIG. 4. Specifically, the jacks 150
(FIG. 4) are extended so that the frame 102 and rail assemblies 104
are elevated relative to the upper horizontal beam 16, and the rail
assemblies 114 are suspended from the wheels 144 (FIG. 4).
[0052] In this position (second position of the coupling
mechanism), the rail assemblies 114 are clear of the upper
horizontal beam 16, so that they can be rolled in the longitudinal
direction A along the wheels 144 (FIG. 4) to their new position, as
shown in FIG. 5d.
[0053] Once the rail assemblies 114 are in their new position, the
coupling mechanism can moved into the first position (FIG. 3), so
that the rail assemblies 114 again rest on the upper horizontal
beam 16, with the frame 102 resting on the rail assemblies 114 as
shown in FIG. 5e. The cables 134 can then be refastened, and the
frame 102 can then be advanced along the (repositioned) rail
assemblies 114. By repeating the above process, the frame 102 can
be advanced along the entire length of the bridge 10 without the
need to lay down or pick up any additional track members to support
the frame 102.
[0054] In one embodiment, small hand winches may be used to advance
the frame 102 along the rail assemblies 114 (when the frame 102 is
in the first position) and the rail assemblies 114 along the frame
102 (when the frame 102 is in the second position). These winches
can be used to lock the frame into a particular working position as
a safety measure. Alternatively, the wheels 144 may be motorized.
In addition to vice members 164, clamps may be provided for locking
the frame 102 in position relative to the rail assemblies 114, to
prevent accidental movement of the frame 102 during a maintenance
operation.
[0055] One skilled in the art will appreciate that the design of
the housing 124 and foot 112 described above are merely one
embodiment of the present invention, and that many variations are
possible without departing from the scope of the present invention.
For example, with reference to FIG. 6, alternate feet 212 and rail
assemblies 214 could be used. Rail assemblies 214 comprise a
generally circular housing 216, with a flattened bottom portion 218
for resting on the upper horizontal beam 16 of the bridge 10,
rather than the square of the rail assemblies 114. The foot 212 has
a shape corresponding to the rail assemblies 214, and a plurality
of bearings 220 are disposed in the foot 212 to permit smooth
longitudinal movement of the foot 212 and the rail assemblies 214
relative to one another.
[0056] It is also within the contemplation of the inventor that the
jacks 150 may be adapted for use with a bridge 10 in which the
upper horizontal beam 16 is of a type other than an I-beam. With
reference now to FIGS. 7 and 8, such alternate embodiments are
described. In these alternate embodiments, identical reference
numerals have been used to those used in FIGS. 3 and 4, with the
letter "a" denoting the alternate embodiment. Thus, the jacks are
denoted by 150a, the housing is denoted by 124a, and so on.
[0057] In FIGS. 7 and 8, the upper horizontal beam 16a is a box
member rather than an I-beam, and alternate embodiments of a foot
112a and rail assembly 114a are shown. In these alternate
embodiments, the jacks 150a are positioned to engage the upper
surface of the upper horizontal portion 118a of the box beam 16a.
Although not visible in FIGS. 7 and 8, cutouts are provided in the
outside edges of the track plate 122a to accommodate the horizontal
portions 162a of the engaging members 158a of the jacks 150a. Thus,
in the first position shown in FIG. 7, the jacks 150a are in the
retracted position, and the horizontal portions 162a of the
engaging members 158a are positioned above both the upper
horizontal portion 118a of the upper horizontal beam 16a, and also
above the track plate 122a. The vice members 164a contact and apply
pressure to the outside of the side plates 126a to fix the frame
102a in position during a maintenance operation. When the vice
members 164a are retracted, the frame 102a can move relative to the
rail assemblies 114a by way of the wheels 144a rolling along the
track plate 122a.
[0058] When the frame 102a has advanced to the end of the rail
assemblies 114a, the horizontal portions 162a of the engaging
members 158a will be aligned with the cutouts (not shown) in the
track plate 122a. Thus, as shown in FIG. 8, the jacks 150a are then
moved into the extended position, causing the horizontal portions
162a to engage the upper surface of the upper horizontal portion
118a of the upper horizontal beam 16a. As the jacks 150a continue
to extend, the frame 102a will be raised into the position shown in
FIG. 8, with the rail assembly 114a suspended from the frame 102a
(by way of the top plates 128a resting on the wheels 144a. This
permits the rail assemblies 114a to move relative to the frame 102a
and the bridge 10 by means of the rail assemblies 114a rolling
along the wheels 144a.
[0059] In one embodiment, a flexible hood connected to a vacuum
source may be used to contain and remove dust and debris resulting
from maintenance operations. Other tools and equipment can also be
used with the present invention. For example, an overhead canopy
can be positioned above the road surface 26, mounted on wheeled
platforms on the sides of the roadway, to follow beneath the
scaffolding structure 100 and capture debris. Catwalks can also be
provided on the scaffolding structure if desired.
[0060] While the embodiments described above have been directed
toward use with a bridge having substantially linear upper
horizontal beams, it is also envisioned that the present invention
may be modified by adapting the rail assemblies and frame for use
with a bridge having curved upper horizontal beams. For example, a
rail assembly comprising a plurality of flexibly connected segments
could be used, permitting the rail assembly to adapt to the
curvilinear shape of the particular upper horizontal beam upon
which it rests. Furthermore, the engaging members of the jacks
could be adapted to apply vice-like inward pressure to the sides of
the upper horizontal beams to maintain the frame in place when the
frame is in the raised position.
[0061] It will be appreciated by one skilled in the art that
numerous other variations and modifications may be made to the
embodiments described above without departing from the scope of the
present invention. All such variations and modifications are
intended to be encompassed within the scope of the present
invention as defined by the appended claims.
* * * * *