Note: Descriptions are shown in the official language in which they were submitted.
METHOD AND APPARATUS FOR PROVIDING TEMPORARY SUPPORT AND A
MEANS FOR RELOCATING ENERGIZED ELECTRICAL CONDUCTORS
Cross-reference to Related Applications
[0001] This is a continuation-in-part of US Patent Application No. 14/946,474
filed November
19, 2015 which in turn is a division of US Patent Application No. 13/810,634
filed January 16,
2013 (now US Patent No. 9,197,041). US Patent Application No. 13/810,634 is a
National Stage
Entry of Patent Cooperation Treaty Application Number No. PCT/CA2011/000902
filed July 21,
2011, which in turn claims priority from US Provisional Patent Application No.
61/344,432 filed
July 21, 2010 and Canadian Patent Application No. 2,710,631 filed July 21,
2010. All of the
applications referred to in this paragraph are entitled "Method And Apparatus
For Providing
Temporary Support And A Means For Relocating Energized Electrical Conductors".
Entireties of
all the applications referred to in this paragraph are incorporated herein by
reference.
Field
[0002] This disclosure relates to the field of repair or replacement of high
voltage power lines
or the supporting structures, insulators and the like related to same, and in
particular, to a
manually actuable lightweight device for mounting onto a high voltage line
tower for the
insulated acquisition and relocation of an energized electrical conductor
supported by the
tower.
Background
[0003] As recognized by Pigott et al in United States patent no. 6,434,810,
which issued August
20, 2002 for a Method for High Voltage Power Line Repair, high voltage power
lines have been
constructed to extend from spaced towers high above terrain which is
practically inaccessible to
land vehicles. As such, a number of methods and devices have been developed to
facilitate the
repair of high voltage power lines by helicopter, where such power lines are
suspended from
each support tower by elongate insulators. Pigott et al describe that such
helicopter-facilitated
repairs have been extremely difficult and time consuming to perform, in that
the tension on the
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power line must be broken so that the line can be lifted out of its support
shoe to facilitate the
line repair. In an attempt to alleviate this problem, linemen have tried to
winch the line upward
from the crossbar at the top of the tower.
[0004] Consequently, Pigott et al teach temporarily attaching a template to
the yoke plate,
which supports a plurality of power lines, so as to receive and position winch
lines on opposite
sides of the yoke plate directly above a power line. The winch lines are
described as extending
from the template to a hand winch, and from the hand winch to attachments with
the power
line on opposite sides of the yoke plate. The winch lines are described as
extending
downwardly to connections with the power line spaced outwardly on opposite
sides of the
yoke plate, and that the winch lines are used to draw the power line upwardly
towards the
template so as to raise the power line out of contact with the yoke plate.
[0005] Thus Pigott et al addresses generally the problem to which the present
disclosure is
addressed; namely, that, because maintenance and refurbishment of critical
transmission and
distribution lines often requires the lines to remain energized and
operational during the
maintenance procedures, this requires the conductors to remain live while
being temporarily
relocated and remain thus insulated from ground and other conductors so as to
provide a safe
working zone when the energized conductor has been temporarily relocated,
allowing safe
replacement of hardware, insulators in the working zone or the placement of
new conductors.
Pigott et al also address the problem that it is often impractical to move
cranes or other
ground-based support vehicles adjacent to the tower or other energized
conductor supporting
structures to facilitate the support and relocation of the energized conductor
to allow
maintenance and refurbishment. Examples of ground-based support vehicles and
attachments
to ground-based support vehicles, such as cranes, are found for example in
United States
patent no. 5,538,207 which issued July 23, 1996, to Devine et al for a Boom
Mountable Robotic
Arm; United States patent no. 6,837,671, which issued January 4, 2005 to
Devine et al for an
Apparatus for Precisely Manipulating Elongate Objects Adjacent to and Such as
Energized
Overhead High Voltage Transmission Lines; and United States patent no.
7,535,132 which
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issued May 19, 2009 to Devine et al for a Live Conductor Stringing and
Splicing Method and
Apparatus.
[0006] In the prior art, applicant is also aware of United States patent no.
1,235,999, which
issued August 7, 1917 to Neeley for a Repair Device for High Voltage Electric
Transmission
Lines. Neeley describes a device adapted to be utilized by workmen for
replacing broken or
damaged insulators which carry overhead electric conductors, and for effecting
an immediate
attachment of the line wires to the insulators, even where the wires are live
or charged with
current. By way of background, Neeley states that overhead lines for
conducting electricity
generally embody a support consisting of a pull and one or more cross arms,
insulators applied
to the cross arm at opposite sides of the pole, and live wires attached
through the medium of
the insulators to the support, and that an important feature in the repairing
or upkeep of such
lines resides in the renewal or replacement of insulators, which may become
damaged or
broken. To provide for this, Neeley discloses a repair device for high voltage
electric
transmission lines which includes a saddle adapted to be adjustably positioned
on a cross arm,
a pin removably seated in the lower portion of the saddle for retaining the
saddle on the cross
arm, a loop pivotally connected to the pin to one side of the saddle, a lever
carried by the loop,
an insulator carried by one end of the lever, and a wire engaging member on
the insulator.
Summary
[0007] The present disclosure is directed to the problem presented to linemen
who are
required to maintain or refurbish transmission and distribution lines which
must remain
energized, but without the use of ground-based support vehicles and prior art
manipulator
attachments, either due to the terrain, or the encroachment or abandonment of
rights of way
adjacent to the affected transmission line towers. The solution, according to
the present
disclosure, is to support a single energized conductor, whether for example it
be a single phase,
a single bundle or the like, and to clear the single conductor out of the work
zone; that is, out of
the way of the area where the linemen must perform the maintenance or
refurbishment. In
particular, the solution provides a relatively lightweight (for example,
manufactured of
aluminium), elongate, rigid mounting arm, and corresponding mounting bracket
on one end of
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the arm, the other end of the arm supporting a pivotally mounted insulator
depending
downwardly from a crank arm, wherein the upper end of the crank arm is
attached to an
actuator which, upon actuation, pivots the crank arm and insulator about the
end of the
support arm so as to rotate up and out of the way an energized conductor
contained in the wire
holder at the bottom end of the insulator. The support arm is temporarily
mounted to an
existing transmission line tower or pole (collectively herein, a tower) so as
to extend outwardly
substantially horizontally therefrom, thereby cantilevering outwardly of the
tower the end of
the arm supporting the crank arm and insulator.
[0008] It is advantageous, however, to firstly vertically lift the conductor
by a short distance, for
example so as to clear the conductor from its existing conductor holder on the
existing insulator
which ordinarily holds the conductor, prior to rotating the conductor out of
the way by pivoting
the crank arm. To accomplish the short vertical lift of the conductor, a
vertical actuating
mechanism is employed. The vertical actuating mechanism is actuated in
sequence with the
rotation of the crank arm step following the vertical lifting of the conductor
step.
[0009] In an embodiment, the vertical actuating mechanism is a vertical
actuator and the
actuator for rotation of the crank arm is a rotation actuator, wherein the
vertical actuator and
rotation actuator operate sequentially to, first, vertically lift the
conductor, and, second, to
rotate the conductor through an arc.
[0010] In another embodiment, in order to accomplish this sequencing, a lower
end of the
crank arm, to which the insulator is mounted, is telescopic as so as to be
telescopically
retractable up into, and telescopically extendable downwardly from, the upper
end of the crank
arm. The rotation actuator may also employ a mechanism, described herein,
which acts as the
vertical actuator to telescopically actuate the lower end of the crank arm
relative to the upper
end.
[0011] Thus for example, where the rotation actuator includes a tensioning
device such as a
hydraulic actuator, screw drive, first winch or the like, tensioning a first
elongate member which
is coupled to the upper end of the crank arm for rotation of the crank arm,
the vertical actuator
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may include a second winch or other tensioning device acting in concert with
the rotation
actuator, for example by piggy-backing on the rotation actuator, as described
more fully below,
which tensions a second elongate member to elevate or lower the lower end of
the crank arm.
Thus the vertical actuator acts on the lower end of the crank arm so that,
upon initial
tensioning of the second elongate member, firstly the lower end of the crank
arm is
telescopically elevated relative to the upper end of the crank arm, and,
secondly, once the
lower end of the crank arm is elevated, then tensioning of the first elongate
member by the
rotation actuator draws the uppermost end of the upper crank arm towards the
support arm so
as to pivot the crank arm about the cantilevered end of the support arm. In an
embodiment a
selectively actuable brake, lock-out or other form of rotation inhibitor may
be provided acting
on the crank arm so as to inhibit rotation of the crank arm until after the
lower end of the crank
arm has been telescopically retracted to vertically lift the conductor.
[0012] The initial upward telescopic translation of the lower part of the
crank arm also thereby
elevates the generally vertically disposed insulator and the wire holder
mounted to the bottom
of the insulator. When the conductor is held within the wire holder, the
loading due to the
weight of the conductor on the insulator to be replaced, for example, is
relieved. Once the
conductor has been uncoupled from the old insulator, that is from the
insulator requiring repair
or replacement, the rotation of the crank arm and insulator will carry the
conductor in the wire
holder in a circular arc about the pivot point of the crank arm on the
cantilevered end of the
support arm to thereby rotate and elevate the energized conductor out of the
work zone. The
present disclosure further includes the corresponding method of operating the
apparatus.
Brief Description of the Drawings
[0013] Figure 1 is, in side elevation view, the complete temporary support
apparatus for
supporting energized conductors according to one embodiment of the present
disclosure.
[0014] Figure 1A is an alternative embodiment of the apparatus of Figure 1.
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[0015] Figure 2 is, in side elevation view, the temporary support apparatus of
Figure 1 mounted
onto a vertical support of a transmission line tower so as to extend
cantilevered outwardly
alongside a cross arm of the tower.
[0016] Figure 3 is the temporary support apparatus of Figure 2, with the
insulator of the
temporary support apparatus elevated so as to support the weight of the
conductor captured in
the wire holder at the bottom of the insulator.
[0017] Figure 4 is the temporary support apparatus of Figure 2, actuated so as
to pivot the
crank arm, insulator and wire holder about the cantilevered end of a support
arm of the
apparatus, so as to thereby elevate the conductor captured within the wire
holder.
[0018] Figure 5 is the temporary support apparatus in its elevated position,
as shown in Figure
3.
[0019] Figure 6 is the temporary support apparatus in its actuated position,
as shown in Figure
4.
[0020] Figure 7 is an alternative embodiment of the temporary support
apparatus according to
the present disclosure, illustrating the use of other forms of tensioning
devices to rotate the
crank arm about the end of the support arm.
[0021] Figure 8A is, in side elevation view, a further embodiment of the
temporary support
apparatus according to the present disclosure, illustrating an alternative
arrangement of
actuator and crank arm the use of a pulley mounted to the lowermost end of the
insulator in
place of the wire holder of Figure 1.
[0022] Figure 88 is the temporary support apparatus of Figure 8A shown in its
actuated
position so as to rotate the crank arm about the end of the support arm.
[0023] Figure 9A is, in side elevation view, a further embodiment of the
temporary support
apparatus according to the present disclosure, wherein the crank arm provides
a laterally
outward offset for the insulator relative to the end of the support arm.
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[0024] Figure 9B is the temporary support apparatus of Figure 9A shown in its
actuated
position so as to rotate the crank arm about the end of the support arm.
[0025] Figure 10A is, in enlarged view, the mounting bracket of Figure 1.
[0026] Figure 10B is, in right side elevation view, the mounting bracket of
Figure 10A.
[0027] Figure 11A is, in upper perspective view, a further alternative
embodiment of the
temporary support apparatus according to the present disclosure wherein an
actuator mounted
internally within the support arm translates two-stage traveller blocks to
produce a
corresponding two-stage actuation of the crank arm by firstly elevating the
lower crank arm
and secondly pivoting the entire crank arm so as to rotate the crank arm from
the vertical to
the horizontal.
[0028] Figure 11B is the temporary support apparatus of Figure 11A, showing
the crank arm
rotated from the vertical to the horizontal.
[0029] Figure 12A is, in side elevation view, an alternative embodiment of the
temporary
support apparatus of Figure 11A.
[0030] Figure 12B is the temporary support apparatus of Figure 12A, showing
the crank arm
rotated from the vertical to the horizontal.
[0031] Figure 13A is, in side elevation view, a further alternative embodiment
of the temporary
support apparatus of Figure 11A, wherein the actuator is a helical screw
drive.
[0032] Figure 13B is the temporary support apparatus of Figure 13A, showing
the crank arm
rotated from the vertical to the horizontal.
[0033] Figure 14A is, in upper perspective view, a further alternative
embodiment of the
temporary support apparatus mounted onto a vertical support of a transmission
line tower so
as to extend alongside a cross arm of the tower.
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[0034] Figure 1413 is, in side elevation view, a close up view of the crank-
arm end of the
temporary support apparatus of Figure 14A.
[0035] Figure 14C is a rear perspective view of the temporary support
apparatus of Figure 14A.
[0036] Figure 14D is a close-up view of the base end of the temporary support
apparatus of
Figure 14A.
[0037] Figure 15 is, in upper perspective view, the mounting bracket shown in
Figures 14A and
14D.
[0038] Figure 16 is, in perspective view, the cantilevered arm shown in Figure
14A.
[0039] Figure 17 is, in side elevation view, the temporary support apparatus
of Figure 14A,
showing the crank arm rotated partway between the vertical and horizontal
positions.
Detailed Description
[0040] As seen in the accompanying drawings wherein similar characters of
reference denote
corresponding parts in each view, the temporary support apparatus 10 for
providing temporary
support to an energized conductor and a means for relocating the energized
conductor out of a
work zone includes a support arm 12 having a base end 12a and a cantilevered
end 12b. A
mounting bracket 14, better seen in Figures 10A and 1013, is adjustably
mounted onto base end
12a. A crank arm 16 is pivotally mounted at pivot 18 to cantilevered end 12b.
Crank arm 16
includes in particular an upper crank arm 16a and a lower crank arm 16b. A
rotation actuator
20 is mounted to support arm 12, to actuate rotation of crank arm 16 about
pivot 18 by
tensioning a first elongate member such as cable 22 alone, or in the
alternative embodiment
described below, by tensioning a rigid first elongate member such as linkage
member 40. An
insulator 24 and corresponding wire holder 26 are mounted to, so as to depend
downwardly
from, lower crank arm 16b.
[0041] Mounting bracket 14 is adjustable in position along the length of base
end 12a of
support arm 12 by the use of a removable fastener, such as pin 14a mounted
through apertures
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formed in a slide collar 14b through which is snugly and slidably journalled
the base end 12a.
Base end 12a includes a spaced apart array of apertures which, depending on
the position to
which collar 14b is slid, may be aligned with the aperture in collar 14b
through which pin 14a is
placed so that pin 14a registers with one of the apertures along base end 12a
to thereby
provide for locking the position of mounting bracket 14 relative to support
arm 12.
[0042] Collar 14b may be pivotally mounted onto base plate 14c by means of a
pivot arm 14d
pivotally mounted at for example an upper end thereof, so as to allow the
rotation of the
opposite end of pivot arm 14b to thereby adjust the angle of the base plate
relative to base end
12a.
[0043] Actuator 20 may be a linear actuator such as a hydraulic actuator,
screw or first winch
for example, or other selectively or manually operable tensioning device. In
the embodiments
of Figures 1 - 7, cable 22 passes under pulley 28a mounted on support arm 12
between
actuator 20 (not shown to scale) and the distal end of cantilevered end 12b,
and over pulley
28b mounted on the uppermost end of upper crank arm 16a, and around pulley 28c
which is
mounted on upper crank arm 16a aligned vertically over lower crank arm 16b.
Cable 22 passes
around pulley 28d mounted at the lower end of lower crank arm 16b. Cable 22
returns
upwardly to where it is attached to upper crank arm 16a for example, mounted
vertically above
lower crank arm 16b. Actuator 20 thus serves both as the rotation actuator and
the vertical
actuator. Initially, the tensioning actuation by actuator 20 in direction A
tensions cable 22
around the pulleys 28a ¨ 28d to impart a vertical elevating tension in
direction B, thereby
urging the vertical translation of lower crank arm 16b telescopically upwardly
in direction C into
the female receiving tube within the lowermost end of upper crank arm 16a.
Because insulator
24 and wire holder 26 are rigidly mounted to, so as to depend vertically
downwardly from, the
lowermost end of lower crank arm 16b, upward translation in direction C of
lower crank arm
16b thereby correspondingly also elevates insulator 24 and wire holder 26.
[0044] As seen in Figures 2 ¨ 4, where the temporary supporting apparatus 10
of Figure 1 has
been mounted onto an upright member 30a of a transmission tower 30, mounting
bracket 14 is
rigidly fastened onto upright member 30a and support arm 12 is translated
horizontally
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outwardly of mounting bracket 14 and then locked into position within slide
collar 14b, so as to
position crank arm 16, insulator 24 and wire holder 26 adjacent, respectively,
the distal end of
cross arm 30b. Old insulator 32 is mounted to the distal end of cross arm 30b.
Conductor 34 is
mounted to the lowermost end of insulator 32. With conductor 34 captured in
wire holder 26,
as seen in Figure 3, actuation of actuator 20 so as to tension cable 22 in
direction A elevates
lower crank arm 16b in direction C upwardly telescopically into the lowermost
hollow end of
upper crank arm 16a, thereby lifting conductor 34 in wire holder 26 to take up
and support the
weight of conductor 34, thereby allowing old insulator 32 to be uncoupled from
conductor 34.
[0045] With conductor 34 uncoupled from insulator 32, further tensioning of
cable 22 in
direction A rotates crank arm 16 in direction D (see Figure 4) about pivot 18
as cable 22
becomes taut; that is, once lower crank arm 16b has been elevated to the full
extent of its
linear vertical travel, so that further tensioning of cable 22 pulls pulley
28b towards pulley 28a.
The rotation of crank arm 16 in direction D thereby also rotates insulator 24
from its downward
vertical position into a raised or elevated position; for example, a
substantially horizontal
position, thereby carrying conductor 34 in an upward circular arc E away from
old insulator 32.
This clears conductor 34 from the necessary work zone, allowing the linemen,
in this instance,
to work on old insulator 32. Once the refurbishment or replacement of old
insulator 32 has
been completed, actuator 20 is actuated oppositely from the raising operation,
so as to allow
cable 22 to extend from actuator 20 thereby allowing crank arm 16 to rotate
downwardly in a
direction opposite direction D, lowering insulator 24, wire holder 26 and
conductor 34 to a
returned or fully lowered position corresponding to the original position of
conductor 34 (as
seen in Figure 2), whereby conductor 34 may be recoupled onto a newly replaced
insulator 32.
Conductor 34 is released from wire holder 26 once the lower crank arm 16b has
been lowered
to its fully lowered position by the complete detensioning of cable 22 and
conductor 34 is
recoupled to the new insulator 32.
[0046] In another embodiment, as seen in Figure 1A, a selectively operable
brake is provided,
such as by replacing the shaft of pivot 18 with a threaded bolt and mating nut
18' which may be
selectively tightened to compress cantilevered end 12b, for example where end
12b is formed
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as a spaced apart pair of ears 12c sandwiching the mounting arm 16c of crank
arm 16
therebetween. Mating nut and bolt 18' compress the ears 12c together,
increasing the friction
and thereby resisting rotation of mounting arm 16c, and thus resisting the
rotation in direction
D of the entire crank arm 16. By selectively inhibiting the rotation of crank
arm 16, the lower
end 16b of the crank arm will retract in direction C upon tensioning of cable
22 before the crank
arm rotates in direction D to thereby sequence the upward telescoping of lower
crank arm 16b.
As would be known to one skilled in the art, the use of nut and bolt 18' as a
selectively operable
brake is just one example of how crank arm 16 may be restrained from rotation
until after the
lower end 16b has elevated, as other forms of brakes or lock-outs, such as by
the use of locking
pins, latches, etc, may be employed. In this fashion, a break or discontinuity
is provided in the
sequencing of the actuation of the vertical actuator followed by actuation of
the rotation
actuator.
[0047] In an alternative embodiment shown in Figure 7, actuator 20 is replaced
with a manual
cranking arrangement, for example employing a second winch 21 for tensioning
cable 22. In a
further alternative embodiment, a static support cable or flexible member 24a
(shown in
dotted line in Figure 7) is employed in tension between the uppermost end of
upper crank arm
16a and the lowermost end of insulator stack 24. Support cable or member 24a
serves to
support insulator stack 24 as it is rotated about pivot 18 in direction D.
Upper crank arm 16a
may be angled outwardly by an inclined angle alpha (a) of, for example,
approximately 135
degrees. Upper crank arm 16a is of sufficient length so that tension on cable
22 imparts a
moment sufficient to rotate the crank arm, insulator stack, wire holder and
conductor in
direction D, so that the resulting tension on flexible member 24a supports the
insulator stack
laterally as it is rotated.
[0048] The apparatus articulation, extension and retraction may be
accomplished using two
separate actuators and/or cables, for example as described below in relation
to Figures 14A ¨
14C and 17. Figures 1 - 7 indicate a 2:1 mechanical advantage using one
pulley; but additional
pulleys could be added to lift heavier loads.
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[0049] In the alternative embodiments of Figures 8A, 8B, 9A and 9B, actuator
20 is directly
connected to crank arm 16 without the use of cable 22. That is, the prime
mover or cylinder of
the actuator 20 engages the crank arm 16 directly via the cylinder rod 20a; in
other words, the
driving member of the cylinder. In Figures 8A and 8B, conductor holder 26 is
replaced with
pulley 26a. As may be seen in comparing the crank arm 16 of Figures 8A and 9A,
crank arm 16
may have more or less offset at its opposite ends, relative to pivot 18. In
the simplified
embodiments of Figures 8A and 9A, no mechanism is provided for elevating a
lower crank arm
16b relative to an upper crank arm 16a.
[0050] In a further alternative embodiment, illustrated in Figures 11A ¨ 11B,
an internal
cylinder actuator is provided. Tensioning is provided by both a cable 22 and a
rigid linkage
member 40. The cable 22 attaches directly to the lower crank arm 16b. The
cable 22 is routed
internally up through the crank arm 16 and exits the top of the upper crank
arm 16a through a
shiv or pulley 28b where the rigid linkage member 40 is attached. In a two
stage actuation, the
rotation actuator 20, which may be a cylinder or a screw actuator, takes up
the cable 22 and
pulls it the distance required to raise the lower crank arm 16b so as to lift
the conductor 34. The
actuator 20 then contacts the rigid linkage member 40 and from that point the
linkage member
40 and cable 22 move together along the support arm 12. Thus as seen in the
further
alternative embodiment of Figures 11A and 11B, actuator 20 is mounted
internally within
support arm 12 and is oriented for actuation in a reverse direction (as
compared to the
embodiment of Figure 1). In particular, the driving member or cylinder rod 20a
extends from
cylinder 20 towards base end 12a of the support arm so as to translate
traveller block 42
attached to cable 223 also towards base end 12a, thereby tensioning cable 22.
Cable 22
extends upwardly from traveller block 42 and over pulley 28b at the upper end
of upper crank
arm 16a, then extends downwardly through the hollow crank arm 16, and in
particular
downwardly through upper crank arm 16a and lower crank arm 16b to the lower
end or base
16d of lower crank arm 16b where the cable 22 is affixed to lower crank arm
16b.
[0051] Thus when rod 20a is extended in direction A, traveller block 42 is
driven towards
traveller block 44 within arm 12 thereby tensioning cable 22 and drawing
upwardly the lower
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crank arm 16b in direction C. Cable 22 is of sufficient length so that as
traveller block 42
engages against traveller block 44, lower crank arm 16b telescopically
retracts into upper crank
arm 16a. Once traveller block 42 engages against traveller block 44, further
extension of rod
20a from cylinder 20 pushes both traveller blocks 42 and 44, thereby drawing
rigid linkage
member 40, connected to traveller block 44, downwardly and along support arm
12 towards
base end 12a. Drawing linkage 40 thusly pulls the upper end of upper crank arm
16a over pivot
18, thereby rotating crank arm 16 in direction D from the position shown in
Figure 11A to the
fully rotated position shown in Figure 11B. An insulator 24 mounted to the
base 16d of lower
crank arm 16b (not shown in Figures 11A or 11B, but shown in Figures 12A and
12B) is rotated
from a vertical alignment in Figure 11A to a horizontal alignment in Figure
11B thereby rotating,
for example a conductor holder 26 or a pulley 26a, mounted to insulator 24
(not shown)
upwardly and out of the way. Thus as seen in Figure 11B, and although not
shown to scale,
cylinder rod 20a, when fully extended from cylinder 20, has pushed traveller
block 42 and
traveller block 44 almost completely to the end of base end 12a thereby
drawing the lowermost
ends of cable 22 and linkage 40 along slot 12d until, at the end of slot 12d,
crank arm 16 has
been rotated to the horizontal. When it is desired to return crank arm 16 to
the vertical, so as
to lower insulator 24, rod 20a is retracted into cylinder 20 thereby drawing
traveller blocks 42
and 44 towards cylinder 20 in a direction opposite direction A. The weight of
insulator 24 acting
about pivot 18 causes crank arm 16 to rotate downwardly in a direction
opposite to direction
D, thereby drawing linkage 40 and traveller block 44 along with crank arm 16
so as to translate
traveller block 44 towards cylinder 20.
[0052] In an alternative embodiment of Figures 12A and 12B, a different form
of traveller
blocks 42 and 44 are illustrated wherein traveller block 42 slides over or
alongside, so as to
overlap, traveller block 44. Once traveller block 42 has been slid completely
alongside traveller
block 44, traveller block 44 is picked up by traveller block 42 so that both
traveller blocks then
continue sliding along support arm 12 in direction A, again thereby drawing
the lowermost ends
of linkage 40 and cable 22 along slot 12d, wherein, in Figure 12A, slot 12d is
positioned along a
side surface of arm 12.
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[0053] In a further alternative embodiment shown in Figures 13A and 138,
cylinder 20 and
corresponding rod 20a are replaced with what is shown diagrammatically as a
helical screw
drive 46 wherein a motor (not shown) drives rotation of threaded rod 46a
thereby conveying a
correspondingly threaded follower 46b along threaded rod 46a to once again
draw, firstly,
cable 22 (connected to follower 46b) in direction A to thereby elevate lower
crank arm 16b in
direction C; and, secondly, once cable 22 has been drawn sufficiently along
slot 12d, follower
46b engages the traveller 44 corresponding to linkage member 40 to thereby
simultaneously
draw the lower end of linkage member 40 also along slot 12d towards base end
12a of support
arm 12. As before, this rotates crank arm 16 in direction D so as to rotate
insulator 24 from the
vertical to the horizontal as seen in Figure 1313.
[0054] A further embodiment employing screw drive 46 is seen in Figures 14A ¨
14C. As
before, screw drive 46 includes a threaded rod 46a mounted within support arm
12. The base
end of threaded rod 46a is seen Figure 14C. Threaded rod 46a is also shown,
partially cut-away,
in dotted outline in Figure 1413. Traveller block 44 shown partially in dotted
outline, is mounted
in threaded engagement on threaded rod 46a so that rotation of rod 46a about
its longitudinal
axis F translates traveller block 44 along slot 12d in direction A or reverse
to direction A,
depending on the direction of rotation of rod 46a. Linkage member 40 connects
traveller block
44 to upper crank arm 16a. Crank arm 16 is pivotally mounted at pivot 18 on
the distal end of
support arm 12 for rotation of crank arm 16 in direction D in a vertical
plane. Pivoting crank
arm 16 also pivots insulator 24 mounted on the lower end of lower crank arm
16b and shown
partially cut-away in Figures 14A ¨ 14C. Crank arm 16 pivots in direction D as
traveller block 44
moves in direction A, carrying linkage member 40 with it.
[0055] In the embodiment of Figure 14C, which is not intended to be limiting,
a crown gear 48
is mounted on the exposed base end of threaded rod 46a, exposed on the base
end 12a of
support arm 12. Crown gear 48 is rigidly mounted to, so as to be orthogonal
to, threaded rod
46a so that rotation of crown gear 48 about axis F also rotates threaded rod
46a. A worm gear
50 is mounted so as to engage with, and drive rotation of, crown gear 48. Worm
gear 50 is
shown mounted vertically, but this is not intended to be limiting. A shaft
having a hexagonal
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head, or bolt head 52, extends from worm gear 50 along its axis of rotation G.
Bolt head 52 is
advantageously sized so as to snugly fit into a standard socket (not shown) of
the kind sold
commercially and adapted for fitting to a hand drill (not shown) for example.
Thus a lineman
carrying a rechargeable hand drill having the appropriately sized socket
mounted thereon
merely has to place the socket onto bolt head 52 and, using the hand drill,
rotate worm gear 50
in order to rotate threaded rod 46a to thereby pivot crank arm 16.
[0056] Second winch 21, shown in Figures 14B and 14C, is mounted onto the
upper side of
linkage member 40. Cable 22 may be extended from, or retracted onto, winch 21
by the
conventional actuation of the winch about axis of rotation H, for example by
the use of a
manual crank handle (not shown) or for example by the use of a crown gear and
worm gear
arrangement, so that winch 21 may be actuated by use of a hand drill, in a
manner similar to
rotating threaded rod 46a as described above and illustrated in Figure 14C. As
before, cable 22
extends through and along upper crank arm 16a so as to be connected to the
lowermost end of
lower crank arm 16b. Actuation of winch 21 telescopically elevates lower crank
arm 16b into,
or lowers the lower crank arm 16b from, upper crank arm 16a to raise or lower
insulator 24.
[0057] Advantageously, winch 21 is positioned on the linkage member 40 so as
to maintain
tension in the cable 22 and thereby maintain the lower crank arm 16b in an
elevated position
during actuation of the screw drive 46 to rotate crank arm 16 in direction D,
such as illustrated
in Figure 17. Positioning winch 21 on the linkage member 40 additionally makes
it easier to
access by a linesman so as to operate the winch 21, for example by using a
manual crank handle
or a powered hand drill tool, as described above, as opposed to mounting the
winch 21 on
upper crank arm 16a, which would increase the distance between winch 21 and a
linesman
climbing the tower 30 to access support arm 12.
[0058] As seen in Figure 14A, support arm 12 may be mounted onto a
cantilevered arm 54,
itself mounted to tower 30 by mounting bracket 56, better seen in Figures 14D
and 15. Guy
wires 58, which extend from tower 30 to support arm 12, may be used to
laterally stabilize the
free end of arm 54 and support arm 12, as well as to help carry the vertical
load of the weight
of the conductor held by insulator 24. Further lateral stabilizers (not shown)
such as rigid or
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flexible members or bracing, may be employed to further laterally stabilize
the free end of the
arm 54 and support arm 12.
[0059] Mounting bracket 56 comprises an L-shaped flange 60, having first and
second wings
60a, 60b for engaging a corner edge 30c of an upright member 30a of the
transmission tower
30. An outer surface of each wing 60a, 60b supports two bolt sleeves 62,
spaced vertically
apart from one another and sized to snugly receive a threaded bolt 64.
Mounting blocks 66,
each having a smooth bore 66a for receiving a portion of the bolt 64 and a
slot 66b for receiving
an outer edge 30d of the upright member 30a, are slid onto the distal ends 64a
of each bolt 64
protruding from sleeve 62. A threaded wingnut 64b is threaded onto the distal
ends 64a of
each bolt 64 to thereby sandwich the mounting block 66 between the sleeve 62
and wingnut
64b.
[0060] Mounting bracket 56 further includes a C-shaped bracket 68 for engaging
and securing
the cantilevered arm 54 to the upright member 30a of the tower 30. C-shaped
bracket 68 is
mounted to, or may be integrally formed with, the outer surface of one of the
wings 60a or 60b
of the L-shaped flange 60, positioned between the spaced-apart pair of bolt
sleeves 62. C-
shaped bracket 68 includes a pair of horizontal arms 68a, 68a extending
orthogonally relative to
the surface of wing 60a or 60b, and is separated by vertical portion 68b.
Bores 68c extend
through wings 68a, sized to slidingly receive 1-bolt 54a to secure the
cantilevered arm 54
between the wings 68a. A height H between wings 68a is sized to slidingly and
snugly receive
cantilevered arm 54 therebetween.
[0061] To mount a support arm 12 to tower 30, so as to enable the cantilevered
end 12b of arm
12 to reach the old insulator 32 supported on a cross arm 30b, a cantilevered
arm 54 may be
mounted to a upright member 30a of tower 30 using mounting bracket 56. The
bracket 56 is
snugly secured to upright member 30a by inserting the outer edges 30d of
upright member 30a
into the slots 66b of the mounting blocks 66, and then tightening the wingnut
64b so as to
compress the slots 66b towards the opposed facing wing 60a or 60b of the L-
shaped flange.
The cantilevered arm 54 is slid into the C-shaped bracket 68 so as to align
one of an array of
bores 54b running orthogonally to a longitudinal axis X of the cantilevered
arm 54 with the
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bores 68c running through the wings of the C-shaped bracket 68. Once the bores
54b and 68c
are aligned, so as to be co-linear, the 1-bolt 54a is inserted through the
bores 54c and 68c to
thereby secure cantilevered arm 54 to an upright member of the tower 30. The
support arm 12
may be mounted to cantilevered arm 54 by means of a pair of mounting brackets
13, 13
extending downwardly from arm 12, which align with a pair of support arm
mounting bores 54c
for receiving bolts or other fasteners to thereby secure the arm 12 to a free
end 54d of
cantilevered arm 54, as illustrated for example in Figures 14D and 17.
[0062] It will be appreciated by those skilled in the art that the actuators
20, as employed in the
various embodiments described herein, may be of different types and that the
embodiments
described herein are not limited to the particular types of actuators
described in relation to
those embodiments. For example, without intending to be limiting, the cylinder
actuator 20
employed to drive the travelling blocks 42, 44 in the embodiment illustrated
in Figures 12A and
12B may be substituted for the screw drive actuator 20 described in the
embodiment illustrated
in Figures 13A and 13B. Further, where herein reference is made to crank arm
16 rotating from
vertical to horizontal, it will be understood by one skilled in the art that,
depending on the
geometry of the actuator relative to the crank arm, the crank arm may not
rotate completely to
the horizontal, but will still operate to move the conductor out of the work
zone. As will be
apparent to those skilled in the art in the light of the foregoing disclosure,
many other
alterations and modifications are possible in the practice of this disclosure
without departing
from the spirit or scope thereof. Accordingly, the scope of the disclosure is
to be construed in
accordance with the substance defined by the following claims.
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