Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02851439 2014-04-08
WO 2013/061072
PCT/GB2012/052664
1
DECK PANEL, LOAD PLATFORM, CLAMP AND TENSIONER
FIELD OF THE INVENTION
The present invention provides a deck panel supportable on a pair of spaced
parallel support (catenary) wires and a platform of a plurality of the
catenary wires
carrying a multiplicity of the deck panels. It also provides a T-clamp useful
e.g. in
platforms of the above kind for attaching tension members e.g. slings to the
wires. It
further provides an in-line tensioning device for catenary cables and its use
in platforms
supported by catenary cables.
BACKGROUND TO THE INVENTION
US-A-5299655 (Margaritis) discloses suspended structures providing a
workplace beneath bridges and other like structures. Cables are each fixedly
connected
at opposite ends to said underlying bridge supports and lie parallel to one
another in a
substantially common horizontal plane spaced a predetermined distance below
the
substructure, tension in the cables being adjustable by means of turnbuckles.
The two
outermost cables are spaced from one another by a distance at least
substantially as
great as the width of said bridge. Load-bearing flooring is supported by the
cables and
extends the full width between the outermost cables and the full length
between the
bridge supports. The floor is constructed of chain-link fence which is
unrolled so as to
lay on the cables, and is wrapped around the cables and secured thereto with
clips, after
which the chain-link fence floor is covered with nylon tarpaulin or other
fluid-
impermeable material.
US-A-5730248 (Apostolopoulos) aims to provide an improvement on such
platforms by reducing the time needed to erect and dismantle them, and to
provide rigid
support for workmen standing or walking thereon. Flooring sections or panels
of sheet
material of elongated rectangular shape corrugated for strength at right
angles to the
cables together form a platform, are supported by the under-bridge
longitudinal cables
in side-by-side relationship and are removably connected thereto. Each
connection is
formed by a plate which engages the upper surface of a panel and a generally U-
shaped
CA 02851439 2014-04-08
WO 2013/061072
PCT/GB2012/052664
2
member which is attached to the plate to extend downwardly therefrom to be
received
in a panel opening and to receive the cable. The free end of the member is
threadedly
attached to another plate wherein the two plates generally cover the opening
with the
cable securely received between the legs of the U-shaped member. US-A-6138793
(Apostolopoulos) provides a connector assembly which has a manually operated
lever
for selectively placing the connector assembly in clamped or un-clamped
positions
relative to the cable and flooring section. However, these connector
arrangements have
been criticised as unduly complex. The first described arrangement it requires
two parts
to be assembled as well as a nut which must be screwed onto the free end of
the
member, i.e., a total of three separate parts as well as an electric or other
wrench for
applying the nut sufficiently tight. The second lever-based arrangement
requires two
parts to be assembled as well as a pin (or nut and bolt) for added safety.
A rope clamp having a pair of jaws for clamping about a rope or cable and
having an eye for attachment of a second rope is shown in US 0779019
(Agobian). The
disclosed utility is for uniting ends of ropes. Forming an attachment at an
intermediate
position along a rope or cable for a second rope, wire, chain or the like in
tension in a
direction out of alignment with the first rope about which clamping is
effected is neither
disclosed nor suggested. A clamp having a pair of jaws for fastening about a
wire rope
and having a hook attached to one of the jaws for attachment of a second wire
rope, e.g.
a guy rope is disclosed in US 0928367 (De Witt). However, it is apparent that
load on
the hook from the guy rope in a direction out of alignment with the main rope
tends to
pull the jaws apart rather than tighten them about the rope. By way of
background, a
further clamp for gripping a cable or rope based on a pair of jaws is shown in
US
4143446 (Down). The jaws are screw clamped together and can accommodate in-
line
an accessory permitting attachment of a hook, eye, shackle, swivel or the
like.
However, it will be apparent from the drawings that the Down attachment only
enables
this to be achieved at an end of the rope.
Some embodiments of the invention provide panels which can be fitted easily
and rapidly to catenary wires with minimal gaps, or with gaps of predetermined
relatively small dimensions, between their ends to form a load platform.
Other embodiments of the invention provide panels that can be fitted to at
least
three support wires in rows and columns with at least two adjacent panels
having a
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
3
common support wire, the panels being configured so that they may be fitted
either in
aligned rows or in a staggered arrangement.
It is a further object of the invention to provide a platform comprising
panels
clipped between catenary wires, wherein the effects of failure of a catenary
wire are
relatively localised, support along the length of the platform being at least
partly
retained.
It is a further object of the invention to provide platforms supported by
catenary
wires in which the cables are optimally adjusted.
A yet further object of the invention is to provide friction clamps e.g. for
use in
association with load-carrying members e.g. straps, wires, chains or slings
that are of
improved structure and properties.
It will be appreciated that the invention has a number of diverse aspects, and
individual embodiments may not achieve ann or indeed any of the above objects.
SUMMARY OF THE INVENTION
In one aspect the invention provides a decking panel having first and second
ends and fasteners at each end for releaseably clipping the panel to a pair of
wires by
which it is to be supported, said fasteners comprising hooks for supporting
the panel on
the wires and catch assemblies each including at least one finger for
resisting lift of the
panel from the wires, the catch assemblies being covered by treadplates hinged
to the
panel with free ends facing outwardly and at least partly overlying the hooks,
raising
the treadplates from the panel providing access to the catch assemblies.
Clipping can be
achieved without the use of tools, which is an advantage in such areas as an
underdeck
of jetties, rigs, bridges and pipe racks. The underdeck can provide a solid
and stable
work platform that feels like scaffolding and users may be able to carry out a
variety of
heavy work tasks off the deck as if it were scaffolding.
In a further aspect the invention provides a decking panel having: first and
second ends; and fasteners at each end for releaseably clipping the panel to a
pair of
wires by which it is to be supported, said fasteners comprising hooks for
supporting the
panel on the wires and at least one catch for resisting lift of the panel from
the wires;
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
4
wherein the hooks and a catch or catches at one end are offset from the hooks
and a
catch or catches at the other end.
In a further aspect the invention provides a decking panel having: first
and
second ends and fasteners at each end for releaseably clipping the panel to a
pair of
wires by which it is to be supported; said fasteners comprising hooks for
supporting the
panel on the wires and catch assemblies at each end of the panel for resisting
lift of the
panel from the wires, each catch assembly comprising a cross-member pivotally
supporting one or more levers each carrying a catch finger, the or each lever
being
rotatable between a raised position where the finger or fingers are clear of
the hooks
and a lowered position where the finger or fingers register with the hooks
from
underneath for clamping a support cable between the hooks and the fingers; and
treadplates at each end of the panel, hinged thereto at pivot axes spaced from
the ends
of the panel and with free ends facing towards the ends of the panel, the
treadplates
being liftable from a normal lowered position in which the or each catch
assembly is
concealed by the treadplate to a raised position in which the or each catch
assembly is
user-accessible.
For use in an inter-tidal zone there may be provided a decking panel for
forming
a load platform, said panel having first and second ends and fasteners at each
end for
releaseably clipping the panel to a pair of wires by which it is to be
supported, the panel
comprising a pair of longitudinal styles, cross-members between the styles and
decking
in the form of a grating or expanded metal.
In a further embodiment the invention provides a load platform comprising
spaced parallel wires supporting a plurality of panels as defined above.
In a further aspect the invention provides a T-clamp for fitting to a rope in
tension and for attachment of a member which in use is loaded in a direction
transversely of the rope, said clamp comprising: first and second elongate
members;
hinge formations at one end of said members forming parts of a hinge that
connects the
members together for movement between an open position in which the rope is
insertable into and removable from the clamp and a closed position in which
the first
and second members contact one another and the rope is retained in the clamp;
first and
second clamping jaws in said members for closing about and frictionally
engaging the
rope, one side of each clamping jaw being adjacent the hinge; first and second
stem
CA 02851439 2014-04-08
WO 2013/061072
PCT/GB2012/052664
regions of each of said members arising from sides of the clamping jaws
opposite to the
hinge and extending away from the hinge in a direction transversely of the
clamping
jaw; and first and second hook or eye regions extending from ends of the first
and
second stem regions opposite to the hinge and together defining an a hook or
eye for
5 receiving an eye or hook of the member, load on said first and second eye
regions
urging the clamp towards its closed position.
The invention also provides in combination a clamp as aforesaid and a wire or
chain sling, the first and second members having eyes and the sling having a
hook.
A load platform according to the invention comprises support wires, decking
clipped to the support wires for providing the platform, and one or more
slings or straps
attached at their upper ends to a structure beneath which the load platform is
slung and
attached at their lower ends to the wires at one or more intermediate
positions along
their length, the attachment being by T-clamps as aforesaid and lower ends of
the slings
being said members, the clamps being configured to frictionally engage the
wires for
impeding the wires from travelling through them.
In another embodiment the invention provides a load platform comprising
support wires and panels clipped to the support wires for providing the
platform,
wherein adjustable support chains are connected to the support wires at
intervals
between their ends for supporting vertical load, and the adjustable support
chains are
connected to support wires by friction clips that surround the support wires
and
frictionally engage therewith to inhibit the support wires from being pulled
through
them in the event of wire failure.
A further aspect of the invention provides a platform comprising: decking
panels each having first and second ends and each comprising (a) fasteners at
each end
for releaseably clipping the panel to a pair of wires by which it is to be
supported, said
fasteners comprising hooks for supporting the panel on the wires and catch
assemblies
for resisting lift of the panel from the wires, and (b) treadplates at each
end of the panel,
hinged thereto at pivot axes spaced from the ends of the panel and with free
ends facing
towards the ends of the panel, the treadplates being liftable from a normal
lowered
position in which the or each catch assembly is concealed by a treadplate to a
raised
position in which the or each catch assembly is user-accessible; at least
three spaced
parallel wires supporting a plurality of decking panels arranged in at least
two columns,
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
6
adjacent decking panels of different columns having a common support wire; one
or
more slings or straps attached at their upper ends to a structure beneath
which the
platform is slung and attached at their lower ends to the support wires at
intermediate
positions along their length; and clamps providing attachment of the lower
ends of the
slings or straps or legs thereof to the support wires, the clamps being
configured to
frictionally engage the wires for impeding the wires from travelling through
them, the
clamps being located on the support wires within the widths of individual
panels and
free edges of treadplates of adjacent panels at a common support wire being
spaced
apart to permit portions of the clamps attached to the support wire to pass
upwardly
between the treadplates.
It will be appreciated that in this embodiment by locating the clamps on the
support wires within the widths of adjacent panels it is not necessary to
space apart
decking panels of the rows at the sling or strap positions. In embodiments
upper ends of
the clamps are formed with eyes for receiving hooks at the lower ends of the
slings or
straps or legs thereof In further embodiments the clamps may comprise first
and second
members hinged together below the support wires, said members having concave
clamping regions for fitting about the support wires and stems extending from
the
clamping regions to above the treadplate, portions of the stems defining eyes
that
coincide for receiving hooks of the slings or strap or legs thereof
A further embodiment of the panel comprises a decking panel having first and
second ends and fasteners at each end for releaseably clipping the panel to a
pair of
wires by which it is to be supported, the panel comprising decking and a
support
framework including a pair of longitudinal styles, wherein the upper regions
of the
styles have upstanding formations and lower regions of the styles having
matching
recesses or sockets in which at least uppermost regions of the upstanding
formations
can be received, whereby when one panel is stacked on another, displacement of
the
upper panel laterally is resisted.
Another aspect of the invention provides a load platform comprising support
wires and panels clipped to the support wires for providing the platform,
wherein the
support wires are secured to tensioners configured for sensing tension and
setting
tension in the wires to a desired value. Although turnbuckle tensioners are
known, the
applicants have not found a turnbuckle tensioner with a built-in load cell or
other
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
7
tension-measuring device. In applications involving load-carrying generally
horizontal
wires in tension, as in the present load platforms, it is desirable to be able
to set a
determined tension in the wires without over-tensioning.
A yet further embodiment of the invention comprises a tensioner for a support
wire, rope or the like comprising a body and oppositely acting screw jacks
together
extensible from and retractable into the body on rotation thereof, attachments
at the
ends of the screw jacks for wire eyes or the like, and a measuring device for
measuring
tension applied to the wire.
It will be appreciated that the features set out above may be used in
combination
with one another and in sub-combinations. Thus any of the preferred decking
panels,
support chain and clamp arrangements, tensioners and load platform
arrangements may
be used in association with one another and, for example the support chain and
clamp
arrangements and the tensioners may be used with other types of decking
panels.
Thus the invention further provides a load platform comprising support or
catenary wires and panels clipped to the catenary wires for providing the
platform,
wherein adjustable support chains and clamps are connected to the catenary
wires at
intervals between their ends for supporting vertical load, and the adjustable
support
chains are connected to catenary wires by friction clips that surround the
catenary wires
and frictionally engage therewith to inhibit the catenary wires from being
pulled
through them in the event of wire failure, the catenary wires being secured to
tensioners
configured for sensing tension and setting tension in the wires to a desired
value.
BRIEF DESCRIPTION OF PREFERRED FEATURES
The above decking panel in embodiments is generally rectangular and comprises
a pair of longitudinal styles and cross-members between the styles. The cross-
members
may include ladder-like cross-members and/or diagonal cross-members defining a
truss-type structure.
Embodiments of the styles are extrusions in aluminium. Such extrusions may in
embodiments each comprise a region of box section into which the hooks fit,
portions
of the region of box section defining outer and inner webs spaced apart
transversely of
the panel, one hook at each end of the panel being fastened to the outer web
of one of
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
8
the styles and the other hook at each end being fastened to the inner web of
the other of
the styles. Such extrusions may further comprise portions of the region of box
section
that define an upper generally horizontal web from which an upstanding wall
arises and
portions that define a lower generally horizontal web formed with a recess
into which at
least uppermost regions of the upstanding walls can be received, whereby when
one
panel is stacked on another lateral displacement of the upper panel is
resisted. Each
style may be formed adjacent each end at its inner vertical web with fixing
formations
for attachment of fastening plates of a catch assembly and/or for attachment
of hooks,
and may be formed adjacent one end at its outer vertical web with fixing
formations for
attachment of a hook.
In alternative embodiments the styles are of rolled steel, e.g. in channel, I
or Z-
section. In this case, the styles may each comprise a portion defining a web
to which
hooks are attached, one hook at each end of the panel being fastened to the
web of one
of the styles directly or at a relatively small spacing, and the other hook at
each end of
the panel being fastened to the web of the other of the styles with a spacing
that is larger
than the spacing for said one style, the styles and hooks being configured so
that the
hooks at one end of the panel are offset transversely of the panel relative to
the hooks at
the other end of the panel. The styles may further comprise portions that
define an
upper generally horizontally-directed web from which upstanding pins, ribs or
other
formations arise and portions that define a lower generally horizontally-
directed web
formed with recesses or sockets into which at least uppermost regions of the
upstanding
pins, ribs or other formations can be received whereby when one panel is
stacked on
another lateral displacement of the upper panel is resisted.
In embodiments of the above panel, the cross-member carries a pair of levers
spaced apart transversely of the panel and interconnected at or adjacent their
ends
facing away from the support cable by a handle. For ease of fitting to support
wires in
both aligned and staggered arrangements, the pair of levers is conveniently
spaced apart
by about one third of the width of the panel. Each finger may be formed with a
recess
defining an upwardly-facing hook for engagement with the underside of the
support
cable or it may have a plate-like surface engageable with the support wire,
friction
between the fingers and the support wire inhibiting lateral displacement of
the panel.
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
9
Decking may be wooden e.g. of plywood, may be of metal or may be of
expanded metal especially where the decking is to be used in tidal conditions
and may
be submerged at some states of the tide.
For support at intermediate longitudinal positions the above load or work
platform may further comprise one or more slings or straps attached at their
upper ends
to a structure beneath which the load platform is slung and attached at their
lower ends
to the support wires at one or more intermediate positions along their length.
Lower
ends of the slings or straps or legs thereof may be attached to the support
wires between
adjacent pairs of panels or may be attached to the support wires at locations
within the
widths of individual panels. In either case, the lower ends of the slings or
straps or legs
thereof may be attached to the support wires by clamps (e.g. two-part hinged T-
clamps)
configured to frictionally engage the wires for impeding the wires from
travelling
through them. Free edges of treadplates of adjacent panels at a support wire
may spaced
apart for access of the support wire and upwardly-facing portions of clamps
attached to
the support wire may extend between the treadplates.
For tensioning the support wires the tensioners may comprise a body and
oppositely acting screw jacks together extensible from and retractable into
the body on
rotation thereof. They may further comprise a ratchet for controlling rotation
of the
body and a handle for effecting rotation, and their opposed ends may
incorporate
bifurcated shackles and pins for attachment to wire eyes or the like, the in-
line sensor
being between one of the screw jacks and a shackle.
With reference to the above clamp, there may be further comprised apertures in
the first and second stem regions adjacent said first and second hook or eye
regions for
receiving a retaining bolt. In some embodiments the first and second stem
regions and
the first and second hook or eye regions together define planar surfaces that
are in
contact in the closed position. To reduce point loads and permit the member to
be at an
angle relative to the clamp, in some embodiments internal faces of the first
and second
hook or eye regions at least adjacent ends of the first and second members
opposite to
the hinge are internally profiled to define a continuous curved surface for
receiving an
eye or hook of the member.
In general in relation to load platforms, the decking may comprise panels
clipped or otherwise releaseably fastened to the wires, in which case
embodiments of
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
the panels comprise a pair of longitudinal styles and cross-members between
the styles.
Lower ends of the slings or straps or legs thereof in some embodiments are
attached to
the support wires between adjacent pairs of panels and in other embodiments
are
attached to the support wires within the widths of individual panels.
Alternatively in
5 some
embodiments the decking comprises tensioned netting clipped to the support
wires, e.g. polyester netting.
BRIEF DESCRIPTION OF THE DRAWINGS
10 How the
invention may be put into effect will now be described by way of
example only with reference to the accompanying drawings, in which like parts
are so
far as practical represented by the same reference numerals, and in which:
Fig. 1 is an isometric view of a short section of a first embodiment of a
suspended load platform and associated support or catenary wires with
treadplates of
deck panels together providing the load platform shown in their raised
position to reveal
the catenary wires and parts of opening mechanisms of the deck panels;
Fig. 2 is a plan view of a first embodiment of a deck panel forming part of
the
load platform of Fig. 1 and Fig. 3 is plan of one end of the panel on a larger
scale;
Fig. 4 is a side view of a casting forming part of an opening mechanism for
the
deck panel of Figs 2 and 3;
Fig 5 is an end view of the deck panel with its treadplates in their closed
flat
position;
Fig. 6 is a partial section of the deck panel on the line A of Fig 3 showing
part of
a style and of the opening mechanism;
Fig 7 is a section of a style forming part of the deck panel of Fig. 2;
Fig 8 is an oblique view of an end of the load panel with its treadplate
raised
showing the release mechanism and a short length of support or catenary wire;
Fig 9 is a perspective view of a first embodiment of a clamp forming part of a
support strap for supporting a catenary wire at an intermediate position along
its length;
Fig 10 is a plan of a tensioning device useful in tensioning catenary cables
of
load platforms of the general kind illustrated in Fig 1, the device being in
its fully
retracted state;
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
11
Fig. 11 is an oblique view of the tensioning device of Fig 10 in its fully
extended state;
Fig 12 is a view on an enlarged scale of an in-line load cell forming part of
the
tensioning device of Figs 10 and 11.
Fig. 13 is a perspective view of a pair of styles forming part of a second
embodiment of the deck panel;
Fig. 14 is a side view of a hook and a lever forming part of the deck panel of
Fig. 12, said lever incorporating an underhook;
Fig. 15 is a partly exploded perspective view of one end of a deck panel
according to the second embodiment, and Fig. 16 is an underneath view of said
end in
in an assembled state;
Fig. 17 is an underneath perspective view of the panel of Fig. 12 with one
treadplate in a partly raised state and the other treadplate in a lowered
state and showing
solid decking;
Fig. 18 is an underneath perspective view of a third embodiment of the panel
employing expanded metal decking and Fig. 19 is an enlarged top perspective
view of
the panel of Fig. 18 showing a treadplate and an adjacent region of decking;
Fig 20 is an underneath view showing six decking panels in position on support
wires;
Fig. 21 is a view showing five decking panels in position on support wires,
with
two of the decking panels staggered relative to the other three;
Fig. 22 is an exploded perspective view of part of a style of a further
embodiment of the panel together with a spacer, hook and cross-member fixing
plate,
the style being in rolled steel;
Fig. 23 is a side view of portions of adjacent deck panels adjacent a common
support wire, styles and hooks being removed to reveal the support wire,
overlapping
underhooks and a second embodiment of a T-clamp fitted to the support wire;
Fig 24 is a front view of the T-clamp shown in Fig. 23;
Fig. 25 is an enlarged perspective view of part of the support wire, the T-
clamp
shown in Fig 23, and a hook and part of a chain forming part of a chain sling
for
supporting a load platform; and
CA 02851439 2014-04-08
WO 2013/061072
PCT/GB2012/052664
12
Figures 26 and 27 are perspective views of first and second members together
forming a clamp as illustrated in Fig. 23, the views showing the inner faces
of the
members.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Fig. 1 shows a short section of work platform erected for demonstration
purposes. Catenary wires (also referred to herein as support wires) 10a, 10b,
10c are
supported under tension in spaced parallel relationship from a fixed
structure, in this
instance posts 17 and rails 16, the ends of the catenary wires being attached
to the rails
16 by attachment fittings 18a-18c. The catenary wires in an embodiment may be
16mm
diameter wire rope, 6 x 36 lay with an internal wire rope core, the internal
core
imparting resistance to stretching. For demonstration purposes in the
illustrated
embodiment an upper set of catenary wires 12a, 12b, 12c is provided.
Adjustable
support chains 14 or slings with attachments 15 at each of their ends are
provided at
intermediate longitudinal positions for supporting the catenary wires 10a,
10b, 10c from
an overlying structure, in this instance the catenary wires 12a, 12b, 12c. In
this
embodiment the attachments 15 at each end of the chains take the form of
friction
clamps e.g. as described below. Deck panels 20a-201 e.g. of length 2-4 metres
(e.g. 2
metres, 3 metres or 4 metres) fit onto and are supported by the catenary wires
10a-10c
in abutting relationship side-to-side and end to end in a column and row
arrangement as
shown. UK working at height regulations require that the deck should have a
minimum
of gaps or spaces through which tools or other items could be inadvertently
dropped,
and similar requirements exist in other countries. Further, there is a risk of
lateral
displacement of the panels e.g. during the course of erection of the platform
and it is
desirable to provide means for increasing the resistance of the load platform
to such
displacement.
The arrangement of Fig 1 is only diagrammatic, and the support for the load
platform will vary widely depending on the structure to which the load
platform is fitted
and the task to be performed. The structure may be e.g. a steel bridge, a
concrete bridge,
a jetty, a marine platform or any other large structure where an underneath
temporary
work platform needs to be provided e.g. for inspection or maintenance
purposes. In
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
13
many instances the overlying structure may incorporate or be fitted with eyes
which
provide convenient attachment points for an under-slung work platform. For
example in
the case of a concrete bridge structure, eye-bolts can be fitted to the sides
and underside
of the bridge. Slings may be fastened between the eyes and the load platform
catenary
wires and may e.g. be single leg or two leg slings e.g. in chain or wire rope.
An oblong
master link at the upper end of each sling may be connected to a respective
eye by a
hook, e.g. a latched or locking hook, or by a shackle or by other fastening
means. The
or each sling leg may have a hook at its lower end that fits under and
supports the
catenary wire, but preferably is fitted at its lower end with a friction clamp
that
surrounds and frictionally engages the catenary wire to both provide local
support for
that wire and resist it sliding through the clamp as described below. In the
case of a jetty
having one or more large steel pipelines passing along it, adjustable support
chains may
be passed over the pipelines from one side to another and the ends of the
adjustable
support chains may act as the adjustable support chains 14 of Fig. 1 carrying
clamps 15.
The number of catenary wires and of rows of deck panels will depend on the
size of the
structure that it is needed to inspect or maintain and in some embodiments the
platform
will extend the whole length and width of the overlying structure or it may
extend over
or along a region of that structure where inspection or repairs are to be
carried out.
As is apparent from Fig. 2, the deck panels 20 may conveniently take the form
of ladder-type structures with styles 22, 24 and cross-members or rungs 26.
Such
structures are more convenient and may carry greater loads than corrugated
metal sheet
panels.
Styles 24 which are conveniently aluminium extrusions are shown in enlarged
section in Fig 7 and are of box-section with at their upper outer edges
upstanding
stepped walls 60 and at their lower outer edges matching recesses 62. Panels
can be
stacked one on top of another for storage or transport with the upper step
regions of the
walls 60 fitting into the recesses 62 to avoid lateral displacement of one
panel relative
to another and to hold the upper panels at a predetermined spacing just above
the lower
panels. In the embodiment shown the height of the box-section is 50mm and its
width is
35mm, its side webs are 2mm thick and its top and bottom walls are 4mm thick.
The
wall 60 has a total height of 12 mm or 15mm, a width at its base of 6 mm and a
width at
its stepped top region of 3mm. The relatively thick base region of the wall 60
and the
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
14
top wall of the box portion together define a step into which wooden decking
or metal
sheet or mesh can fit and be retained. The 3mm thick top region of the wall 60
fits into
the recess 62 of an overlying style which is 3mm wide and 3mm high. The
dimensions
given above can be varied without departing from the invention, but are
intended to
provide a general teaching as to preferred dimensions and proportions for
some, but not
all, embodiments of the invention. The cross-members or rungs 26 may be
square, oval
or any convenient section and are attached to the styles to form a rigid
structure.
Further, parallel ladder-type cross-members as illustrated are only one
possible form of
construction and other forms of framework e.g. planar truss frameworks e.g.
with a
single diagonal pair of cross-braces, two or more pairs of cross-braces or
Allan or
Howe-type truss configurations could equally be used, the over-riding
requirement
being for a lightweight open framework with sufficient strength for the
intended load
and giving sufficient support for the intended decking.
Decking 40 is laid on the ladder-type or other framework structures and is
attached thereto, the decking being of timber, metal sheet or metal mesh or
grating,
aluminium or steel being preferred. Where the platform is of mesh or grating,
it may
conveniently be used to erect a platform in tidal conditions where it will be
covered
with water at some states of the tide. In the present embodiment the decking
may be of
plywood.
Opposed ends of the deck panels are formed with hooks 28a, 28b, 30a, 30b
attached to the styles 22, 24 for fitting opposed ends of the deck panels onto
respective
pairs of catenary wires 10a, 10b or 10b, 10c as shown in Fig. 1. As can be
seen in Fig 3,
hooks 30a, 30b are attached asymmetrically to styles 22, 24 within the box
section of
each style. Hook 30a is attached to the outer vertical web of style 22 and
hook 30b is
attached to the inner vertical web of style 24, the corresponding hooks at the
opposite
end of the panel having the reverse fixing arrangement. The hooks have a
thickness in
this embodiment of 6mm and resist bending. The staggered arrangement of the
hooks at
each end when a pair of panels 20a, 20g has adjacent ends supported by a
common
catenary wire 10b allows the panels to be in alignment without interference
between the
adjacent hooks of the two panels.
Each deck panel is provided at each end with a catch sub-assembly or operating
mechanism 32, 34 for retaining the panel in position on its catenary wires
against lifting
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
or other displacement forces e.g. from wind or in the case of a load platform
that may
be submerged at some states of the tide from estuarine or tidal currents. The
catch sub-
assemblies are normally covered by hinged treadplates 52 which normally lie
flat but
which can be rotated upwards to give access to the underlying catch sub-
assembly 32 or
5 34. Retaining fingers 36a, 36b, 38a, 38b are movable into contact with
the catenary
wires from below to prevent the deck panels being inadvertently lifted off the
catenary
wires e.g. in high winds. Again as seen in Figs 3 and 5 the fingers 38a, 38b
are laterally
offset in one direction and the corresponding fingers at the opposite end are
laterally
offset in the opposite direction so that fingers of adjacent panels do not
clash when a
10 pair of panels 20a, 20g has adjacent ends supported by a common catenary
wire 10b.
As apparent from Fig. 3 a catch sub-assembly for an end of a treadplate
comprises a tubular cross-member 54 which provides a pivot axis for a pair of
operating
levers 42a, 42b and generically indicated as 42 in Fig. 4. Each operating
lever which
can be made as a casting comprises a base 46, an upstanding web 48 formed with
15 apertures into which handle 44 fits, an aperture 50 for forming a
bearing with cross-
member 54 which fits into that aperture, and a finger or under-hook
generically
indicated as 38 which projects forwardly and is movable into and from
engagement
with the underside of catenary cable 10 as shown in Fig. 8. The fingers 38 in
this
embodiment are bar-shaped and have width greater than their depth, this aspect
ratio
being selected so that they present relatively wide friction surfaces to the
catenary
cable. The width of the fingers in an embodiment may be about 35 mm. When the
deck
panel is in position on a pair of cables, gravity maintains the fingers 38a,
38b in
engagement with the undersides of the cables and the weight of the base 46 and
web 48
acting about the pivot provided by cross-member 54 urges the fingers upwardly.
The
resulting frictional force at each end of the panel provides resistance to the
panel
becoming displaced laterally on the cables e.g. because of slight slope the
cable as when
workers are standing on the platform created by the deck panels or heavy
objects are
placed on it, or as previously mentioned by wind and/or tide. An advantage of
the
present mechanism is that it can operate purely by gravity, no additional clip
or
fastening mechanism being needed, although the use of such additional
mechanisms is
not excluded if additional reassurance is required. As is apparent from Fig 5,
the cross-
member 54 is located a short spacing inboard of the ends of the styles 52, 54
and at a
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
16
vertical position below the top of the styles. Compared to a front-hinged
treadplate
carrying locking fingers, the pivot axis can be moved further away from the
wire. The
position of the cross-members longitudinally and vertically relative to the
ends of the
styles can be adjusted for specific tasks so that e.g. if a deck panel is
required to clip
onto something other than a cable e.g. a support of steel angle, then only
minor
adjustment of the position of the cross-member 54 is needed.
A first cross-member 64 extends between styles 22, 24 immediately behind the
operating levers 42 and carries hinges 66. A second side of the hinges
attaches to a
second cross-member 68 of angle section fitted to the treadplate 52. Thereby
the
treadplate 52 is hinged to the panel for rotation about an axis spaced inboard
and
slightly above the pivot axis for the release mechanism provided by cross-
member 54.
As previously explained, it will normally lie flat as shown supported by the
horizontal
top walls of the styles 22, 24 as in Fig 5 (where a slight gap is shown for
clarity) or by
support pads on the upper surfaces of the styles but can be lifted by raising
its
forwardly-facing free edge as in Fig. 8. In the illustrated embodiment the
cross-member
54 is located 40mm inboard of the ends of the styles 22, 25, whereas the
treadplate
hinge is located about 201mm inboard. It will be noted that the ends of the
operating
levers 42 are located almost immediately underneath the inner hinged ends of
treadplate
52. If the panel is subject to lift e.g. by wind the fingers 38a, 38b will
tend to be rotated
away from register with the brackets 30a, 30b, tending to release catenary
wire 10. As
most clearly apparent in Fig. 6 the levers 42 then contact the treadplates 52,
but are
unlikely to lift the treadplates 52. The reason is that the line through the
points of
contact of the levers 42 with the treadplate 52 is close to the axes of hinges
66 and
although upward load may be applied to treadplate, that load exerts little
rotational
power on the treadplate. Magnetic catches (not shown) adjacent the free end of
the
treadplate provide additional resistance to unintended lifting of the
treadplate and since
the catches can be spaced along the styles 22, 24 from the axis of hinge 66
they can
offer significant resistance to inadvertent rotation. The free edge of the
treadplate
extends beyond the styles 22, 24 and overlaps the hooks 30a, 30b, almost
overlying the
centre of the hooks with the shortfall in this embodiment being about 3 mm.
Accordingly when two panels are assembled end-to-end on a common cable, the
gap
between the support surfaces that they provide can be as little as 6 mm and
the
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
17
treadplates almost meet one another with no downwardly curved region between
them
where articles can lodge. However, the position of the free edges of the
treadplates is
arbitrary and a wider gap can be adopted e.g to permit the stem of a T-clamp
on the
wire rope to pass upwardly between them as described below.
Laying a deck panel on its catenary wires is a two-person operation. A person
at
each end of the panel lifts the treadplates 52 to a vertical position, grips
handle 44 and
lifts that handle to a vertical position, rotating the fingers 38a, 38b clear
of hooks 40a,
40b. The handles 44 are then conveniently positioned for carrying the panel.
At the start
of laying, the panel is positioned over the catenary wires e.g. 10a, 10b and
lowered into
place. Release of the handles 44 permits the opening mechanisms to rotate by
gravity
until the fingers 36 engage the catenary wire, after which a small force on
the
treadplates 52 allows them to fall under gravity into their fully lowered
position. The
mechanism is therefore robust and simple to operate, and it is resistant to
inactivation as
a result of paint or other materials which are likely to become deposited on
it during
service and which in other designs of deck panel jam the release mechanism and
may
prevent operation.
Fig 8 shows the treadplates 52 partially raised to reveal the release
mechanism.
Spacer tubes 70a, 70b on cross-member 54 between the styles 22, 24 and the
operating
levers 42a, 42b define asymmetric locations for the levers and fingers 38a,
38b. In this
way the fingers of adjacent deck panels at ends facing one another on the same
catenary
wire do not interfere.
Fig. 9 shows a generally T-shaped strap clamp 15 used in particular to fasten
a
strap 14 to a catenary wire 10a, the strap providing support to the catenary
wire at a
position partway along its length. Up to now attachment between the adjustable
support
chains and the catenary wire has been via hooks as are conventional for rope
or chain
slings, but although these provide lift they offer no resistance to pulling
the catenary
wire through them. There is no reason to expect a catenary wire to break or be
cut
through, but provision for very rare events with serious consequences is
desirable. Strap
clamps 15 are formed in halves 80, 81 pivoted together at 82 and together
define a
cavity 84 which surrounds and frictionally engages the catenary wire. Through
holes 86
receive a captive bolt and integral threaded fitting to receive the threaded
end of the
bolt. (not shown) to hold the parts firmly together about the wire and exert a
frictional
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
18
load on the wire preventing it being pulled through the clamp even if the wire
should
break or be cut. The upper end 88 of the clamp in this embodiment is
bifurcated to
receive an eye of a support wire or chain which can be attached to the clamp
by a pin
inserted into through-holes 90. In consequence, should the catenary wire be
cut or
break, vertical support is maintained and the damage to the load platform is
localised. In
this embodiment owing to the close spacing between treadplates of adjacent
decking
panels the strap clamps 15 are fitted to the support wires between adjacent
deck panels
and fitting within the width of a deck panel is not possible. As apparent in
Fig. 1,
therefore, small gaps are present between adjacent panels 20c, 20d, 20i, 20j
to permit
stems of the strap clamps to pass upwardly above the level of the deck panels
and
provide attachment for wire or chain slings or the like.
Deck panels in aluminium according to the embodiments described above may
be lightweight e.g. about 14 kg/m2 and may for example have a loading capacity
of
0.5kN to 5.5kN UDL/m2 depending upon the requirements of a particular job.
They are
easily manoeuvrable and easy to rig, and installation time may be reduced
compared to
scaffolding.
The combination of catenary wires, support straps and clamps is also useful
where polyester tension netting is provided between catenary wires in place of
the
panels described in the previous Figures.
It has been found that the catenary wires of load platforms of the present
kind
give optimum performance and stability when the catenary wires that provide
support
are tensioned at or adjacent a best value which will, of course, vary
depending on the
particular structure under which the load platform is to be slung, and that
excessively
high or low tensions are better avoided. For that purpose the catenary wires
may
incorporate in-line load cells of the kind illustrated in Figs 10-12. Thus
such a
tensioning device may have body 100 fitted with oppositely acting jack screws
102, 104
shown fully retracted in Fig. 10 and fully extended in Fig 11. A reversible
ratchet
mechanism 116 and handle 118 enables body 100 to be rotated in either
direction, so as
to extend or retract the screw jacks and hence increase or decrease the
tension of a
catenary wire into which the tensioner is incorporated In an embodiment the
handle and
ratchet mechanism enable a person to develop approximately 50N (50kg) force to
wind
the tensioner in or out. The pre-tension on the catenary wire is important as
if the
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
19
tension is too high it is necessary to reduce the load capacity of the decks.
So in some
embodiments applicants pretension between 5 and 10kN, using the handle. The
screw
jacks terminate at a first end fitting 106 and a second end fitting 108 each
connected to
a shackle 112, 114 for receiving an eye of a catenary cable or the like which
is
securable in place by pin 120, 122. The pins are inserted into holes in the
shackle and
are held in place by smaller retaining pins 126.
Between the end of jack screw 104 and shackle 114 the end fitting 108 is an in-
line load cell incorporating a pre-calibrated spring-operated load measuring
arrangement providing an output by movement of indicator member 128 through a
calibrated window, the member indicating by its position the load which e.g.
may be
between 0 and 30 kN. It will be appreciated that other types of load cell may
be
employed, e.g. based on strain gauges and electronic devices including a
display, but a
simple spring-loaded device may be more convenient especially where the
platform is
to be in place for extended periods and is subject to adverse weather. However
a
transducer could be incorporated to provide an overload indicator alarm.
Fig. 13 is perspective and partly inverted view of styles 22, 24 forming part
of a
load platform according to a second embodiment of the invention, the styles
being
aluminium extrusions having the same cross-section as in Fig 7 and provided
with
hooks 28a, 28b at one end and hooks 30a, 30b at the other end. Each style is
formed
with a region defining a box section formed in an inner face or web 212
adjacent the
ends thereof with patterns of fixing holes 218, 218a, in this case four, for
attachment of
a catch sub-assembly and/or for attachment of hooks 28a, 28b; 30a, 30b.
Apertures 218
also adjacent the ends and coinciding with the patterns of fixing holes
correspond to
tubular cross-members 54. The region of box section also has an outer face or
web 210
formed adjacent one end with fixing holes 214 for a hook 28a, 28b; 30a, 30b.
With this
arrangement the hooks may be fitted to the outer or inner webs or faces of the
box
section as appropriate, using fixing holes in the same spatial arrangement,
and fixing
plates for the catch sub-assemblies may use the same spatial arrangement of
fixing
holes on the inner webs 212. However on each style only a single hook can be
attached
to the outer face or web. The inner webs 212 are also formed adjacent their
ends with
fixing holes 222, 222a for hinge plate pivots and fixing holes 220, 220a for
decking
cross-members.
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
Fig. 14 shows a hook plate 28 and a lever 36a' forming part of a catch sub-
assembly 32 or 34. The hook plate has a downwardly-facing hook region 224
having at
its forward end a linear lead-in region 232 leading to a quarter-round upper
forward
region 234, an upper linear central region 236 which in the case of 16mm wire
rope
5 may be about 5 cm in length (i.e. about a third of the diameter of the
rope) and leading
to a curved rear region 238. With this hook profile, the panel may be fitted
onto a
support wire 10a, 10b or 10c with a certain amount of misalignment or twisting
being
accommodated without damage to the rope. The hook plate is formed with a
pattern of
fixing holes 230 corresponding to those in the styles and also at its lower
edge with a
10 recess bounded by faces 226 and 228 to permit the plate to slide into
the hollow box
region of a style without interference from recess 62. Catch lever or
underhook 36a' is
formed with aperture 244 so that it can fit rotatably onto cross-member 54 and
adjacent
its rear or inner end with fixing hole 246 for attachment of handle 44. It has
an
outwardly or forwardly facing finger 240 formed at its upper edge with an
arcuate
15 recess 242 for receiving a support wire, the centre of the hook and the
centre of the
recess 242 coinciding at line 248.
In Fig 15 which is a view of an end of a deck panel in partly exploded view,
there appears one of the two decking cross-members 250 which is of inwardly-
facing
angle-section so as to underlie and support the ends of decking 40 with side
plates of
20 said cross-members fastened to the styles 22, 24 at fixing holes 220.
Treadplate 52 has
attached to its rear end on the underside thereof an attachment member 252
also of
angle-section formed with side plates 254a, 254b with through holes for hinged
attachment at fixing holes 22 of the styles, the position of the hinge axis
for each
treadplate being defined by the location of the fixing holes 222. Also
appearing in Fig.
15 is catch sub-assembly 32 comprising cross-member 54 which has forwardly and
rearward-facing curved regions and upper and lower planar regions that non-
rotatably
fit into apertures 278 (Fig 22) of mounting plates 256a, 256b. The levers or
underhooks
36a", 36h" fit rotatably onto the cross-member 54 and are positioned
transversely of the
cross-member by friction collars 36a". As may be seen, their spacing is about
one third
of the width of a deck panel to facilitate positioning of adjacent panels on
different
support wires both in alignment and in staggered relationship as described
below.
Handle 44 is connected between the levers or underhooks adjacent inner ends
thereof.
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
21
The mounting plates 256a, 256b are each formed with fixing holes 258 disposed
in a
pattern corresponding to those in the styles. Fig 16 shows an end of the deck
panel with
both the treadplate 52 and the catch sub-assembly 32 attached between the
styles. The
underside of a deck panel with one of its treadplates raised appears in Fig.
17, the
decking 40 being of plywood or other sheet material. Fig. 18 is an underneath
view of
another embodiment of the decking panel with decking 260 of expanded aluminium
mesh or honeycomb or aluminium grating. Since this form of decking is more
flexible
than plywood, a longitudinal stiffening bar 262 is fitted. In the above deck
panels,
catches may be provided, e.g. magnetic catches, for holding the treadplates in
their
lowered position when installed as part of a load platform in a work area
against
inadvertent lifting through the action of wind or water currents e.g. in an
intertidal zone.
Fig. 19 is an underneath view of panels 20a-20c of one column and 20g-20i of
an adjacent column, the panels being in alignment and alignment being
facilitated by
the offset relationship in the hooks and the catch sub-assemblies 32, 34. Fig
21 is an
underneath view on an enlarged scale showing ends of panels 20a-20c of one
column
and panels 20h, 20i of another column, this staggered relationship within rows
being
facilitated by the relatively close spacing of the underhooks of the catch sub-
assemblies
32 and 34.
Although aluminium is a preferred material, generally square sections in steel
may be rolled for some markets where steel is more practical and the rolled
sections
may have complementary protuberances and recesses on their upper and lower
faces
which interfit to allow stable stacking as described above although the
precise shapes
for aluminium cannot be duplicated in rolled steel and rolled steel styles
will differ from
those shown Rolled steel sections may be of any conventional shape provided
that a
vertical web portion is provided, and they may, for example be of channel, I
or Z-
section, channel section being convenient in some embodiments. Further
sections are C-
or channel section with their flanges formed at their ends with return (in-
turned) regions
or flanges which in some embodiments can significantly increase strength and
stiffness.
In Fig. 22 a style 274 of channel section is formed adjacent its ends with a
pattern of
fixing holes 276 corresponding to the pattern of fixing holes 230 in hook
member 28. A
spacer block 270 is provided and has fixing holes 272 in a pattern
corresponding to that
in the style 274. Also shown is fixing plate 256a of a catch sub-assembly. It
will be
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
22
appreciated that a spacer block 270 may be provided at each end of the
resulting
decking panel in the style 274 on one side but not the other, and in this way
the hooks
28 may be attached in a similar staggered arrangement to those in the
previously
described embodiments. As regards stacking the panels, the styles may further
comprise
portions that define an upper web from which upstanding pins, ribs or other
formations
arise and portions that define a lower web formed with recesses or sockets
into which at
least uppermost regions of the upstanding pins, ribs or other formations can
be received
whereby when one panel is stacked on another lateral displacement of the upper
panel is
resisted, these pins, ribs, etc. are not shown but can easily be implemented.
In Figs 23-25 there is shown end regions of a pair of adjacent load platforms
having a common support wire 10b to which the load platforms are clipped inter
alia by
brackets 28a, 30b and underhooks 36a' and 36b'. Above support wire 10b the
free ends
of treadplates 52 are spaced apart to define a gap of e.g. about 25mm. The
wire 10b
carries a T-clamp generally indicated by the reference numeral 280 having a
clamping
region that fits tightly around and friction grips the wire 10b and a stem
that arises from
the support wire and passes between the support plates so that its upper
regions are
accessible above the support plates. The T-clamp comprises clamping members
282,
284 interfitting at their base with a pair of spaced barrel hinge formations
310, 312 on
the first member 282 between which fits barrel hinge formation 314 on the
second
member 284, the hinge being completed by hinge pin 286. Above the barrel hinge
the
members 282, 284 are formed with generally semi-cylindrical clamping regions
281,
283 which fit around and grip the cable 10b, their axes being parallel to and
spaced
from the hinge axis. Inner faces of the clamping regions 281, 283 are formed
with
inclined gripping teeth 315 matching the lay of the wire rope 10b, the inner
diameter of
the clamping regions being slightly smaller than the wire rope, e.g. 15.75 mm
for a wire
rope of diameter 16mm so that they can firmly grip the rope but not crush it.
Each
member 282, 284 has a stem region 316, 318 arising from the clamping region,
the stem
region having a width greater than its depth and the two stem regions together
having a
depth of e.g. about 17mm so that the stem can pass between the plates 52.
Adjacent the
upper end of the stem region the member 284 is formed with a socketed through-
hole
288 for receiving the head and threaded region of clamping bolt 301 and member
282 is
formed with a corresponding threaded through-hole 290 for receiving the
threaded
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
23
region of bolt 301 to permit the halves of the clamp to be fastened firmly
together about
the support wire. Each of the clamping members 282, 284 is formed at its head
with a
formation defining an eye region 294, 296, the eye regions together defining
eye 292.
As can be seen in Figs 23, 26 and 27 the inner faces of the stems 316, 218 are
planar
and continue without change of attitude into planar faces of eye regions 294,
296 so that
in the closed position the two members 282 and 285 touch one another as
apparent in
Fig. 23. It will be appreciated that other profiles are possible provided that
the two
members can close and touch one another, but the illustrated profile is
convenient and
easy to manufacture. The inner profiles of eye-regions 294, 296 are generally
quarter-
round or otherwise form a generally continuous smooth curve as best seen in
Fig, 23 so
that when engaged by a clamping hook, rope other member to be tensioned, load
on the
member to be tensioned is transferred equally to both eye regions and the load
can be
applied in directions up to 45 in any direction whilst applying pulling force
but not
unacceptable twisting force to the clamp. Without a smooth curved surface of
this kind,
there would be an increased risk of a hook of a sling or the line applying
point loads
which would limit the rated tensional load that the T-clamp can accept. The
members
282, 284 are conveniently drop forgings in alloy steel e.g. Grade 100 alloy
steel and
may be zinc passivized so that they can withstand harsh external environments.
A hook 302, e.g. a safety hook, of a chain sling is insertable into the eye
292 and
provides a lower connection for the chain sling. The eye region 292 is
generally oval or
otherwise has extended height to allow the T-clamp to sit generally vertically
on
support wire 10b, and the hook 302 is configured to be rotatable in any
direction at an
angle of up to about 45 to the vertical, thereby permitting the loading on
the individual
eye-regions 294, 296 of the clamping members to be equlised. It will be
appreciated
that if a T-clamp as shown here is fitted about a support wire 10b, hook 302
is engaged
therewith and the cable 304 is tensioned, then the clamp will be held tightly
about the
wire irrespective of whether bolt 301 has been inserted and a substantial
clamping force
is exerted by simple tension applied to the eye regions 294, 296, so that at
least a
temporary fixing to the wire 10b can be made with a minimum of labour. The
retaining
bolt and the sockets 288-290 are configured so that for an intended support
cable the
clamp cannot be over-tightened, and one of the major purposes of bolt 301 is
to prevent
CA 02851439 2014-04-08
WO 2013/061072 PCT/GB2012/052664
24
a clamp once fitted to support wire 10b from being inadvertently dropped
before
attachment of a hook or other tensioning device.
It will be appreciated that various modifications may be made to the
embodiment described herein without departing from the invention, the scope of
which
is defined by the accompanying claims.
