Note: Descriptions are shown in the official language in which they were submitted.
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BASKET TRANSPORTABLE BY HELICOPTER FOR USE
ON ELEVATED CABLES OR INSTALLATIONS
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the
servicing of elevated cables or installations, such
as high voltage power lines and, more particularly,
pertains to a new basket structure suited for
supporting workmen during servicing operations.
Description of the Prior Art
Over the years, various helicopter portable
basket structures have been developed for servicing
elevated cables or installations, such as high
voltage power transmission lines. For instance,
United States Patent No. 4,478,312 issued on October
23, 1984 to Kurtgis, United States Patent No.
4,422,528 issued on December 27, 1983 to Patterson
and Canadian Patent laid-open application No.
2, 055, 639 filed on November 15, 1991 in the names of
De Forges de Parny et al. all disclose a basket
structure suspended on rope slings from a helicopter
by means of an appropriate lifting harness system.
Such arrangements, wherein the basket structure is
supported underneath the helicopter, suffer from
several disadvantages. For instance, in the case of a
malfunctioning of the helicopter implying an
emergency landing, the basket structure has to be
dropped to permit landing of the helicopter.
Furthermore, when the basket structure is disposed at
the end of downwardly depending slings as mentioned
hereinbefore, the helicopter pilot is not in a
position to accurately assess the position of the
basket structure, thereby rendering the installation
thereof on elevated cables quite arduous and time
consuming.
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Accordingly, attempts have been made to
overcome the above mentioned drawbacks. For example,
United States Patent No. 5,328,133 issued on July 12,
1994 to Charest et al. discloses a basket structure
which is removably mounted at one end of a support
arm extending laterally outwardly of a helicopter.
Although the system described in the above
mentioned patent constitutes an improvement over
previously known helicopter basket carrying systems,
it has been found that there is a need for a new
basket structure adapted to be carried in a compact
manner by a helicopter in order to provide additional
clearance to the rotor blades of the helicopter,
while still providing the required clearance above
ground level during take-off and landing operations.
SUMMARY OF THE INVENTION
It is therefore an aim of the present
invention to provide a basket adapted to be
transported in a compact manner laterally outwardly
of a helicopter.
It is also an aim of the present invention
to provide a basket adapted to be traversed over
obstacles depending from elevated cables.
It is a further aim of the present
invention to provide a basket which is relatively
easily installable on elevated cables.
Therefore, in accordance with the present
invention, there is provided a basket adapted for
attachment to a support arm extending laterally
outwardly from a helicopter used to carry the basket
to elevated cables or installations, comprising a
container structure having a bottom support surface
and an open top end for providing access to the
bottom support surface, the container structure being
displaceable between a collapsed position wherein the
container structure has a reduced height and an
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erected position wherein the container structure has
a full height.
In accordance with another general aspect
of the present invention, there is provided a basket
adapted for attachment to a support arm extending
laterally outwardly from a helicopter, comprising a
frame structure having a bottom support surface and a
top surface joined together in an axially adjustable
relationship, the top surface defining an opening for
providing access to the bottom support surface, the
frame structure being displaceable between collapsed
and erected positions for selectively reducing and
increasing axial dimensions thereof, whereby the
basket can be carried in the collapsed position and,
once on site, extended to the erected position for
safely receiving at least one operator.
BRIEF DESCRIPTION OF THE DRAWINGS
Having thus generally described the nature
of the invention, reference will now be made to the
accompanying drawings, showing by way of illustration
a preferred embodiment thereof, and in which:
Fig. 1 is an end elevational view of a
collapsible basket structure removably mounted at one
end of a support arm extending laterally outwardly
from a helicopter in accordance with a first
embodiment of the present invention;
Fig. 2 is a side elevational view of the
collapsible basket structure illustrated in a
collapsed position thereof and temporarily supported
on a pair of laterally spaced-apart parallel elevated
cables by means of a pair of front and rear
articulated extendable and retractable support arms;
and
Fig. 3 is a side elevational view of the
collapsible basket structure shown in an erected
position thereof and supported on the elevated cables
by means of four railway wheel support arms.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
Now referring to the drawings, there is
shown a collapsible basket structure 10 adapted to be
detachably mounted at the end of a support arm A
extending laterally outwardly of a helicopter H used
to carry the collapsible basket 10 to and away from
elevated installations, such as high voltage lines.
The collapsible basket 10 generally
comprises a rectangular inner framework 12 adapted to
be slidably received in a telescopic fashion within
an associated rectangular outer framework 14. It is
understood that the external dimensions of the inner
framework 12 are slightly less than the internal
dimensions of the outer framework 14.
As seen in Figs. 2 and 3, the inner
framework 12 includes a rectangular top frame
structure 16 and a rectangular bottom frame structure
18 rigidly interconnected to each other through four
upstanding corner posts 20. A rectangular floor or
bottom support surface 22 is mounted to the bottom
frame structure 18. The bottom support surface 22 is
preferably made of a corrugated plate of rigid
material. Protective grids 24 are provided about the
perimeter of the inner framework 12 to prevent
equipment from falling out from the inside of the
inner framework 12.
Similarly, the outer framework 14 is
provided with rectangular top and bottom frame
structures 26 and 28 rigidly joined by four
upstanding corner posts 30. The top frame structure
26 defines a rectangular top opening to provide
access to the bottom support surface 22 of the inner
framework 12, whereas the bottom frame structure 28
defines a rectangular bottom opening which is
slightly greater than the external rectangle formed
by the upstanding corner posts 20 of the inner
framework 12, thereby allowing the inner framework 12
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to be selectively vertically moved into and out of
the outer framework 14 through the rectangular bottom
opening thereof.
All the parts of the bottom and outer
frameworks 12 and 14 are preferably made of welded
metallic tubing and plates.
As seen in Figs. 1 and 2, the collapsible
basket 10 can be locked in a collapsed position
wherein the inner framework 12 is retracted within
the outer framework 14 and held in place by means of
a pair of opposed catch members 32 extending
respectively frontwardly and rearwardly from the top
frame structure 16 of the inner framework 12 for
engaging subjacent portions of the top surface of the
top frame structure 26 of the outer framework 14.
Each catch member 32 consists of a rigid flat plate
pivotally mounted at 33 on the top surface of a cross
flange member 34 forming part of the top frame
structure 16 of the inner framework 12.
The collapsible basket 10 can be readily
unlocked from its collapsed position by manually
pivoting the catch members 32 to an idle position
(see Fig. 3) wherein the catch members 32 extend in a
generally crosswise direction relative to the
collapsible basket 10 so as to overly respective
flange members 34, thereby clearing the top surface
of the top frame structure 26. This operation may be
facilitated by previously slightly lifting the inner
framework 12 so as to elevate the catch members 32
above the top surface of the top frame structure 26
in order to eliminate the friction forces which are
induced when the catch members 32 are rotated while
still being in contact with the subjacent portions of
the top frame structure 26 of the outer framework 14.
The inner framework 12 can be manually lifted via a
rope or handle (not shown) attached to the bottom
support surface 22.
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Once the catch members 32 have been pivoted
inwardly to their respective idle positions, as
described hereinbefore, the collapsible basket 10 can
be displaced to an erected position thereof for the
purpose of safely receiving at least one workman
therein. This is achieved by lowering the inner
framework 12 to an extended position wherein the
inner framework 12 depends downwardly from the outer
framework 14, as seen in Fig. 3.
A pair of opposed inner shoulders 36 extend
respectively along the front inner surface and the
rear inner surface of the rectangular bottom frame
structure 28 of the outer framework 14 to form a
resting surface against which the undersurface of
corresponding flange members 34 may rest to retain
the inner framework 12 in its lowered suspended
position relative to the outer framework 14.
As seen in Fig. l, the collapsible basket
10 is locked in its collapsed position when installed
at the end of the support arm A of the helicopter H.
This advantageously provides additional clearance
between the basket 10 and the rotor blades B of the
helicopter H, while still providing the clearance
between the skids S of the helicopter H and the
undersurface of the basket 10 which is required to
ensure that the basket 10 will not interfere with the
landing of the helicopter H. Indeed, the bottom of
the basket 10 has to be at a higher elevation than
that of the skids S so that the helicopter may land
at any time while still carrying the collapsible
basket 10. The additional clearance obtained between
the rotor blades B and the collapsible basket 10
facilitates the manoeuvres which the helicopter pilot
has to accomplish in order to place the basket 10,
for instance, under a pair of laterally spaced-apart
parallel cables C so that the basket 10 can be
subsequently suspended therefrom, as will be
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explained hereinafter. This operation necessitates
that the helicopter H be displaced sideways towards
the cables C with the rotor blades B being disposed
above the cables C and the collapsible basket 10
thereunder, whereby it is extremely advantageous to
be able to maximize the spacing between the top of
the collapsible basket 10 and the rotor blades B . By
using a collapsible basket in accordance with the
present invention, it becomes possible to anchor the
basket at a lower level with respect to the
helicopter H, thereby providing additional clearance
between the basket and the rotor blade B, while still
maintaining the required clearance between the basket
and the skids S of the helicopter H.
As seen in Fig. 1, the collapsible basket
10 is detachably mounted to the support arm A of the
helicopter H via an inverted L-shaped support member
38 detachably secured to a helicopter side of the
outer framework 14. The inverted L-shaped support
member 38 includes an elongated vertical tubular
portion 40 adapted to be slidably inserted within a
pair of vertically aligned U-shaped brackets 42
extending laterally outwardly from the helicopter
side of the outer framework 14. According to one
embodiment of the present invention, one U-shaped
bracket 42 is secured to the top frame structure 26
and the other to the bottom frame structure 28 with
both U-shaped brackets 42 being located midway
between the front and rear ends of the collapsible
basket 10. A lock pin 43 is transversely inserted
through each U-shaped bracket 42 and through the
vertical tubular portion 40 of the inverted L-shaped
support member 38 to prevent axial removal of the
latter from the U-shaped brackets 38. A hook 44 is
aligned with the U-shaped brackets 42 and extends
laterally outwardly from an undersurface of the
bottom frame structure 28 of the outer framework 14
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for engagement within the open bottom end of the
elongated vertical tubular portion 40 of the inverted
L-shaped support member 38 to prevent the same from
pivoting outwardly away from the helicopter side of
the outer framework 14.
The inverted L-shaped support member 38
further includes a horizontal tubular portion 46 to
which a cross member 48 is welded or otherwise
secured so as to extend generally in the longitudinal
plane of symmetry of the collapsible basket 10. A
carrying member 50 having a generally inverted V-
shaped configuration is secured at opposed lower ends
thereof to respective opposed end portions of the
cross member 48. A channel (not shown) extending in a
direction parallel to the horizontal tubular portion
46 of the inverted L-shaped support member 38 and
having a square or rectangular cross-section is
defined at an apex 52 of the inverted V-shaped
carrying member 50. The channel is opened towards the
bottom so that the carrying member 50 may be
suspended in a stable manner on the support arm A of
the helicopter H so as to prevent rotational movement
of the collapsible basket 10 about the support arm A.
Furthermore, it is pointed out that the apex 52 of
the carrying member 50 is substantially in vertical
alignment with the center of gravity of the
collapsible basket 10 to further improve the
stability of the basket 10 during transportation.
Abutments (not shown) are provided on the support arm
A to prevent linear movement of the basket 10 along
the support arm A.
The collapsible basket 10 further comprises
two pairs of railway wheel support arms 54 and 56
disposed on respective opposed sides of the outer
framework 14 for carrying railway wheels 58 rotatably
mounted thereon. The wheels 58 may be motorized or
not and are configured and disposed to ride over a
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pair of laterally spaced-apart parallel elevated
cables C, as seen in Fig. 3.
The first pair of railway support arms 54
is disposed on the helicopter side of the outer frame
14. As seen in Fig. 2, each railway support arm 54
includes first and second elongated portions 60 and
62 pivotally connected to one another via a pivot pin
64. The first elongated portion 60 of each railway
wheel support arm 54 is inserted in a pair of
vertically aligned brackets (not shown) extending
laterally outwardly from the helicopter side of the
outer framework 14 and removably secured thereto by
means of lock pins (not shown). Each railway wheel
support arm 54 further includes a lock pin 66 which
can be transversally inserted through the first and
second elongated portions 60 and 62 to lock the
railway wheel support arm 54 in a straight line
configuration.
The second pair of railway support arms 56
are disposed on the opposite side of the outer frame
14. As seen in Fig. 3, each railway support arm 56
includes first and second elongated portions 68 and
70 pivotally connected to one another via a pivot pin
72. Each railway wheel support arm 56 further
includes a lock pin 73 which can be transversally
inserted through the first and second elongated
portions 68 and 70 to lock the railway wheel support
arm 56 in a straight line configuration. The first
elongated portion 68 of each railway wheel support
arm 56 is articulated at the bottom end thereof to
the bottom portion of the corresponding corner posts
30 of the outer framework 14 via a universal joint
74, or the like. This allows each railway wheel
support arm 56 to be folded down along the side of
the outer framework 14 during transportation of the
collapsible basket 10 by the helicopter H, as seen in
Figs . 1 and 2 . Each railway wheel support arm 56 can
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be locked in an upstanding position, as seen in Fig.
3, by first pivoting the railway wheel support arm 56
within a U-shaped bracket 76 secured to the top end
portion of the associate corner post 30 and by
subsequently inserting a lock pin 78 through the U-
shaped bracket 76 and the railway wheel support arm
56.
The collapsible basket 10 further includes
a pair of front and rear extendable/retractable arms
80 and 82 respectively pivotally mounted to a front
bottom extension 84 and a rear bottom extension 86 of
the outer framework 14. More specifically, the front
extendable/retractable arm 80 is mounted for rotation
about a pivot 88 between vertical and horizontal
positions, as indicated by arrow 90 in Figs. 2 and 3.
Similarly, the rear extendable/retractable arm 82 is
mounted for rotation about a pivot 92 between
vertical and horizontal positions, as indicated by
arrow 94 in Figs. 2 and 3. The front and rear
extendable/retractable arms 80 and 82 are each
attached to one end of a cable 96 which is attached
at the other end thereof to the outer framework 14 in
order to limit the downward pivot of the front and
rear extendable/retractable arms 80 and 82 to 90
degrees to the vertical. The front
extendable/retractable arm 80 can be held in its
upstanding vertical position by means of a retention
arm 98 extending frontwardly from the top frame
structure 26 of the outer framework 14 and having at
a distal end thereof a U-shaped bracket 100 through
which a lock pin 102 may be removably transversally
inserted after having pivoted the front
extendable/retractable arm 80 upwardly into the U-
shaped bracket 102. Similarly, the rear
extendable/retractable arm 82 can be held in its
upstanding vertical position by means of a retention
arm 104 extending rearwardly from the top frame
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structure 2 6 of the outer f ramework 14 and having at
a distal end thereof a U-shaped bracket 106 through
which a lock pin 108 may be removably transversally
inserted after having pivoted the rear
extendable/retractable arm 82 upwardly into the U-
shaped bracket 106.
The front and rear extendable/retractable
arms 80 and 82 are each provided at a respective
distal end thereof with an axle 110 at opposed ends
of which a pair of wheels 112 are rotatably mounted.
As seen in Fig. 2, the wheels 112 are adapted to ride
on a given pair of laterally spaced-apart parallel
elevated cables C.
As indicated by arrows 114 in Fig. 2, the
front and rear extendable/retractable arms 80 and 82
may be extended or retracted to vary the length
thereof in order to lower or raise the collapsible
basket 10 with respect to the elevated cables C.
Furthermore, as depicted in Figs. 2 and 3, the front
and rear extendable/retractable arms 80 and 82 can be
rotated as per arrow 116 upon themselves to allow the
wheels 110 to be placed on a pair of spaced-apart
cables C from below, as will be described
hereinafter.
According to a preferred embodiment of the
present invention, the extendable/retractable arms 80
and 82 each consist of a hydraulic cylinder having a
piston rod equipped with a swivel for allowing the
axle 110 connected therewith to be rotated about the
piston rod. In this case, a motor 118 can be mounted
on the front bottom extension 84 to power the front
and rear extendable/retractable arms 80 and 82.
Furthermore, it is noted that the tubular
structure of the inner and outer frameworks 12 and 14
can advantageously be used as an oil reservoir.
In operation, the collapsible basket 10,
which is in its collapsed position with the second
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pair of railway wheel arms 56 folded down along one
side thereof, is suspended from the support arm A of
the helicopter H via the carrying member 50, as
illustrated in Fig. 1. Then, the collapsed basket 10
is carried to a length of elevated cables where an
operation has to be carried out. The helicopter H
approaches the elevated cables C sideways so as to
place the horizontal tubular portion 46 of the
inverted L-shaped support member 38 above the cables
with the collapsed basket 10 underlying the cables C.
Then, the horizontal tubular portion 46
which extends crosswise relative to the subjacent
pair of laterally spaced-apart cables C is lowered
onto the cables C by the helicopter H. As seen in
Fig. 1, a V-shaped guide 120 can be fixed to the
undersurface of the horizontal tubular portion 46 of
the inverted L-shaped support member 38 to ensure
proper positioning of the horizontal tubular portion
46 on the cables C. Once the horizontal tubular
portion 46 properly rests on the cables C, the
support arm A is lowered by the helicopter H so as to
move the support arm A out of engagement with the
carrying member 50.
Thereafter, the helicopter H moves sideways
away from the cables C so as to withdraw the support
arm A from between the carrying member 50. The
helicopter H is then brought back down onto the
ground and a platform (not shown) is removably
mounted to the helicopter H for allowing an operator
to take place thereon laterally outwardly of the
helicopter H. Once this operation has been completed,
the platform is carried laterally adjacent to the
suspended basket 10 to allow the operator to place
the wheels 112 onto the cables C. This is
accomplished by first pivoting the front and rear
extendable/retractable arms 80 and 82 to their
respective upstanding positions, second rotating the
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front and rear extendable/retractable arms 80 and 82
as per arrows 116 about their respective longitudinal
axes so as to place the axles 110 parallel to the
cables C, third extending the extendable/retractable
arms 80 and 82 between the cables in order to pass
the axles 110 above the cables C, fourth rotating the
front and rear extendable/retractable arms 80 and 82
as per arrows 116 about their respective longitudinal
axes so that the axles 112 extend transversally of
the cables C with the wheels 112 in vertical
alignment with the corresponding underlying cables C,
and fifth retracting the extendable/retractable arms
80 and 82 to lower the wheels 112 on the cables C.
After the wheels 112 have been positioned
on the cables C as described above, the
extendable/retractable arms 80 and 82 are further
retracted in order to lift the collapsible basket 10
and, thus, raise the horizontal tubular portion 46 of
the inverted L-shaped support member 38 above the
cables C. In this position the collapsed basket 10 is
suspended from the cables via the front and rear
extendable/retractable arms 80 and 82, as seen in
Fig. 2.
Thereafter, the inverted L-shaped support
member 38 is detached from the outer framework 14 and
placed on the platform (not shown) . The basket 10 is
then erected and the operator transferred therein.
Subsequently, the second pair of railway wheel
support arms 56 are unfolded and secured in their
respective upstanding positions. Then, the front and
rear extendable/retractable arms 80 and 82 are
extended so as to lower the railway wheel 58 onto the
cables C. Once this operation has been accomplished,
the front and rear extendable/retractable arms 80 and
82 are disengaged from the cables C and placed
thereunder in their idle position. At this stage, the
basket 10 is suspended from the cables C via the
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first and second pairs of railway wheel support arms
54 and 56, as illustrated in Fig. 3. The wheels 58
may be motorized to displace the basket on the cables
C. Alternatively, the basket 10 can be manually
propelled.
49hen an obstacle, such as a hardware
attached to the cables C is encountered, the front
and rear extendable/retractable arms 80 and 82 can be
used for traversing the collapsible basket 10 over
the obstacle. This is accomplished by first
positioning the front wheels 58 as close as possible
to the obstacle, second positioning the wheels 112 of
the front extendable/retractable arm 80 on the
downstream side of the obstacle, third retracting the
front extendable/retractable arm 80 so as to lift the
front of the basket 10, fourth pivoting the second
portions of 62 and 70 of the front railway wheel
support arms 56 and 58 outwardly so as to disengage
the front wheels 58 from the cables C, fifth
advancing the basket 10 on the cables C so as to
place the front wheels 58 on the downstream side of
the obstacle, sixth pivoting and locking the second
portions 62 and 70 of the front railway wheel support
members 56 above the cables, seventh retracting the
front extendable/retractable arm 80 so as to lower
the front wheels 58 onto the cables C, and finally
placing the front extendable/retractable back to its
idle position. The rear extendable/retractable arm 82
is used in a similar manner to pass the rear wheels
58 on the downstream side of the obstacle.
Finally, the basket 10 can be removed from
the cables C by generally following the reversed
steps required for installing the same onto the
cables C.
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