Note: Descriptions are shown in the official language in which they were submitted.
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SPECIFICATION
This invention relates to helicopter landing pads, and
5 more particularly to portable landing pads adapted for transport
by a helicopter.
In helicopter logging and mineral exploration operations,
it is often necessary to land a helicopter in remote areas that are
10 characterised by uneven or multi-pitched terrain that is at least
partially covered with obstacles such as boulders or stumps.
Accordingly, helicopter landing pads must typically be constructed
at such remote locations before the helicopter logging or mineral
exploration operations may begin.
It is standard procedure in the helicopter logging and
mining industries to construct helicopter landing pads on-site from
timber and other materials that may be available. However, such
wooden landing pads are difficult and very time consuming to build.
20 In some cases, it is additionally necessary to first collect and
retrieve suitable timber and materials over a large area before the
building of the helicopter landing pad may be commenced.
Significant quantities of timber and materials may be required,
since (depending upon the terrain) a wooden landing pad may have
25 to be tiered in several stages in order to allow for proper
clearance for the helicopter rotor. Owing to the variability in
timber supplies and other materials suitable for the construction
of a wooden helicopter landing pad that one may find at any given
remote location, wooden landing pads are of non-uniform
30 construction; this leads to an increased likelihood that a given
wooden landing pad may be insufficiently strongly constructed and
may collapse.
2I97023
Previously known portable helicopter landing pads have
been proposed for use in the helicopter logging and mining
industries and in other operations where it may be necessary to
land a helicopter on uneven or multi-pitched terrain covered with
5 obstacles, but have been found to be unsuitable for use in such
rugged terrain due primarily to their cost, complexity, and/or poor
ground clearance. In U.S. Pat. No. 3,489,380, Vanderlip discloses
a portable helicopter landing pad that is designed to permit the
landing of troops and supplies in densely foliated areas, but that
10 must be set upon a relatively level clearing if one is to be able
to land the helicopter itself upon it. Soloy, in U.S. Pat. No.
4,116,408, discloses a portable helicopter landing pad having a
folding deck, which must be folded before the landing pad may be
transported by a helicopter. Telescopically extensible legs are
15 provided for in the Soloy pad in order that it may be set upon non-
level ground; however, since a folding deck is more susceptible to
unwanted collapse, the foldable deck structure requires the use of
multiple braces between the legs in a configuration that
significantly interferes with ground clearance, thereby rendering
20 the Soloy pad unsuitable for use in rugged terrain. In addition,
since it is often advantageous in helicopter logging and mining
operations to quickly and repeatedly relocate a portable helicopter
landing pad (as the worksite progresses), the requirement that the
Soloy pad be folded before it may be transported limits its utility
25 in such operations.
These disadvantages may be overcome by providing a
portable helicopter landing pad of simple and economical
construction that may be carried in a fully assembled state beneath
30 a helicopter, and quickly set up over obstacles present at a remote
landing site. An object of one aspect of the present invention is
to provide an improved portable helipad possessing these qualities.
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In accordance with one aspect of the present invention,
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there is provided a portable helipad comprising a deck supported
by plural legs, of which at least one is extensible. Leg braces
extending from the legs connect to associated brackets (or other
5 suitable means of attachment) within associated zones of attachment
on the underside surface of the deck, thereby increasing the ground
clearance of the inventive portable helipad as compared to certain
prior portable helipads in which leg braces extended from one leg
to another. Preferably, the associated bracket of each leg brace
10 is located (within the associated zone of attachment of such leg
brace on the underside of the deck) so as to minimize the
likelihood of engagement of the deck support structure with ground
obstructions. One suitable location is in the vicinity of the
peripheral margin of the deck at the boundary equidistant between
15 the leg to which such leg brace is attached and the nearest other
leg. Advantageously, the leg braces are in compression under load,
in order that some portion of any load applied to the portable
helipad is supported by the leg braces. This allows for the use
of less material in the construction of the deck, since all load
20 is not concentrated in the vicinity of the legs. Reduced deck
material allows for the construction of a lighter portable helipad.
Conveniently, the legs and leg braces of the portable helipad are
releasably secured to the deck by pins or the like in order that
the portable helipad may be rapidly assembled and disassembled
25 without the use of tools.
In accordance with a further aspect of the present
invention, there is provided the combination of a helicopter and
a portable helipad comprising a deck supported by a suitable number
30 of legs, of which at least one is extensible. Leg braces
extending from the legs connect to associated brackets (say) within
associated zones of attachment on the underside surface of the
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'eck. Deck engagement means on the underside of the helicopter
releasably attach the portable helipad to the helicopter, and
helicopter engagement means secured to the deck complement the deck
engagement means. Preferably, the deck is constructed of an open-
5 weave material so as to reduce wind loading on the portable helipadduring transport, to reduce the overall weight of the portable
helipad, and to allow precipitation (primarily snow) to fall
through the open-weave material so as to resist build-up (of snow)
on the portable helipad when it is situated at a remote location.
DETAILED DESCRIPTION
In drawings which illustrate embodiments of the invention;
Figure l is a sectional side elevation view of a portable helipad
forming one embodiment of the present invention with a helicopter
resting thereupon;
20 Figure 2 shows the portable helipad of Figure l in a side elevation
view;
Figure 3 is an enlarged exploded view of an extensible leg of the
portable helipad of Figure l;
Figure 4 is an enlarged view of a pin of the portable helipad of
Figure l;
Figure 5 is an enlarged partially sectional view of the connection
30 between the deck and a leg of the portable helipad of Figure l;
Figure 6 is an enlarged view of an extensible leg brace of the
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ortable helipad of Figure l;
_
Figure 7 is an enlarged partially sectional elevation view of the
ground engagement and anchoring platform of the portable helipad
5 of Figure l; and,
Figure 8 is a plan view of a deck panel of the portable helipad of
Figure 1.
In Figure 1, the portable helipad illustrated and
generally designated 10 includes a deck 14 supported by short
extensible legs 16 (one shown) and long extensible legs 18 (one
shown). Short and long extensible legs are provided in order to
15 facilitate the use of the illustrated portable helipad on sloped
terrain. Short and long extensible leg braces 20 and 22 (seen as
dotted lines in Figure 1) extend respectively from ground
engagement and anchoring platforms 26 at the distal end of each
extensible leg 16 and 18 to brackets 24 fastened to the underside
20 surface of deck 14 within the associated zones of attachment of
both leg braces 20 and 22, (the associated zones of attachment
being defined with respect to each leg brace as the region that
lies between the top of the leg to which such leg brace is
connected and a boundary that is substantially equidistant from the
25 top of that leg and the top of the nearest other leg, but not
extending beyond the boundary of equidistance between the top of
that leg and the top of the nearest other leg at any particular
point along the boundary). In the Figures, the illustrated bracket
24 is located at a point on the underside surface of deck 14
30 adjacent the peripheral margin of deck 14 that is substantially
equidistant between short leg 16 and long leg 18. A helicopter 12
is illustrated resting on top of the portable helipad 10 as
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'eployed on sloped and multi-pitched terrain.
-
Although not shown in the embodiment of the inventionillustrated in the drawings, it will be clear to those skilled in
5 helipad design that not all of the legs supporting deck 14 are
required to be extensible; if one or more of the legs are non-
extensible, the deck 14 may nevertheless in most cases be put into
a generally horizontal plane regardless of the terrain upon which
the portable helipad is set, by appropriate adjustment of some or
10 all of the remaining extensible legs. It will also be clear to
those skilled in helipad design that leg braces 20 and 22 may
advantageously be connected to brackets located at any point within
their associated zones of attachment, most preferably substantially
adjacent the peripheral margin of the deck at the boundary
15 equidistant between the leg to which such leg brace is attached and
the nearest other leg.
As is best seen in Figure 3, each extensible leg
comprises an upper segment 28 which is releasably secured to deck
20 14 by flanges 38 (discussed further below), and a replaceably
removable lower extensible segment 30 that is sized to slidingly
engage the upper segment 28. Both the upper segment 28 and lower
extensible segment 30 of the short extensible legs 16 are shorter
than are the corresponding segments 28 and 30 of the long
25 extensible legs 18; see Figure 2. Spaced-apart holes 32 and 34 are
provided in upper segment 28 at a distance from one another that
corresponds to an integral multiple of the distance between spaced-
apart holes 36 provided along the entire length of lower extensible
segment 30. The length of each extensible leg is fixed following
30 longitudinal adjustment (by sliding lower extensible segment 30
relative to upper segment 28) by inserting pins 40 (Figure 4)
through holes 32, 36 and 34, 36 in the upper segment 28 and lower
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xtensible segment 30 of each extensible leg. The pins 40 may be
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secured in place with cotter clips (not shown), and are fastened
to upper segment 28 by a chain 42 to prevent loss of same.
Various combinations of long or short lower extensible
segments 30 may be fitted to upper segments 28 of each extensible
leg 16 or 18 as needed in order to maintain deck 14 in a generally
horizontal plane when positioning the portable helipad over various
10 terrain and obstacles. Figure 2 indicates the maximum and minimum
slopes upon which the portable helipad may be positioned when all
of the short-leg lower extensible segments 30 are used together
with the short-leg upper segments 28, and all of the long-leg lower
extensible segments 30 are used together with the long-leg upper
15 segments 28.
As seen in Figures 1 and 2, deck 14 includes deck panels
44 (shown as a dotted line) releasably affixed to the upper surface
of framework 46, the framework 46 comprising side I-beams 47 and
20 plural cross I-beams 49 releasably secured together with pins 40.
Deck panels 44 further comprise an open weave mesh landing surface
48 and a panel frame 50 to which mesh landing surface 48 is rigidly
affixed; see Figure 8. Releasable attachment of deck panels 44 to
framework 46 is accomplished by means of pins 40, which engage
25 through holes (not shown) in the side I-beams 47 and plural cross
I-beams 49 and corresponding holes (not shown) in panel frame 50.
Hooks of a conventional sort (not shown) for releasable securement
of the helicopter 12 to the portable helipad during shutdown (to
prevent the helicopter 12 from being blown off of portable helipad
30 10 by strong winds) penetrate the open weave mesh landing surface
48 and are removably affixed to cross I-beams 49 with bolts (not
shown). Eyes (not shown) are provided in the vicinity of the
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orners of deck 14 for releasably attaching portable helipad 10 to
corresponding deck engagement means such as cables (not shown) of
the sort conventionally used for attaching cargo to the underside
of helicopter 12. Alternatively, cables (not shown) may be rigidly
5 affixed directly to deck 14. In either cable arrangement, it will
be clear to those skilled in helipad design and to those skilled
in the piloting of helicopters that any forwardly disposed cables
should preferably be longer than any rearwardly disposed cables,
in order that the portable helipad 10 may fly level, and that a
10 flag or other means to create drag may be releasably affixed to the
portable helipad in order to prevent the portable helipad from
spinning during transport.
Legs (including both the short and long extensible legs
15 16 and 18, and any non-extensible legs [not shown]) are releasably
secured to deck 14 by pins 40 joining flanges 38 on the upper end
of each leg to the free ends of side I-beams 47 and end cross I-
beams 49; see Figure 5. Alternatively, it will be clear to those
skilled in the art of helipad design that legs 16 and 18 may be
20 releasably fastened to sockets (not shown) rigidly affixed to
framework 4 6.
As seen in Figure 6, each of the short and long
extensible leg braces 20 and 22 comprises an upper brace segment
25 56 releasably secured to an associated bracket 24 by a pin 40
engaging threaded flange 58, and a replaceably removable lower
extensible brace segment 62. A ground engagement and anchoring
platform 26 is releasably secured to threaded flange 58 at the free
end of lower extensible brace segment 62 by a pin 40; see Figure
30 2. Spaced-apart holes 64 and 66 are provided in upper brace
segment 56 at a distance from one another that corresponds to an
integral multiple of the distance between spaced-apart holes 68
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rovided along the entire length of lower extensible brace segment
62. The length of each extensible leg brace is determined in gross
by inserting pins 40 through holes 64,68 and 66,68 following
longitudinal adjustment by sliding lower extensible brace segment
S 62 relative to upper brace segment 56. Then, further fine
adjustment of the length of each leg brace (including both the
short and long extensible leg braces 20 and 22, and any non-
extensible leg braces [not shown]) may be effected by rotating the
leg brace, so as to cause the threading-in or threading-out of
10 threaded flanges 58 at both ends of the leg brace through matingly
threaded ends 70 of the leg brace. The thread pitch 72 of threaded
flanges 58 and of threaded ends 70 is the same in magnitude but
opposite in direction at the top and bottom ends of each leg brace
in order to allow for the tightening or slackening of the leg brace
15 by rotation as described.
Figure 7 shows the ground engagement and anchoring
platforms 26 that are attached to the distal end of legs 16 and 18
(and any non-extensible legs [not shown]), and to leg braces 20 and
20 22 by pins 40. Pin 40 is engaged to a platform 26 and a leg
through hole 74, and a separate pin 40 engages a threaded flange
58 of a leg brace 20 or 22 through hole 76. The ground engagement
and anchoring platforms 26 are perforated at points 78 to
facilitate spiking to stumps or the ground (not shown) upon which
25 portable helipad 10 is positioned, and spike 80 is provided in
order to limit the translational movement of portable helipad 10
with respect to the surface upon which the portable helipad 10 is
positioned.
Alternative embodiments may exist which are within the
scope of the invention, whose scope is defined in the appended
claims. The shape of the deck, the number and extensibility of
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egs, the positioning of leg brace brackets on the underside
surface of the deck within the associated zone of attachment for
each leg brace, the preferred manner of effecting connections or
attachments, the mechanical means chosen to permit extensibility,
5 and other mechanical details are all variable and within the
ordinary skill of helipad designers.
