CA2037984C - Landing pylon - Google Patents

Abstract

A truncated pyramidal pylon, has outwardly reflectant side walls each sloping at 8°-10° to the vertical for helicopters and 3°-6° to the vertical for fixing wing aircraft, The outwardly reflectant side walls are adapted to give a stronger reflection to an aircraft or helicopter on approach path as desired and a lesser but substantial reflection in other directions.
The pylon may be constructed from hingedly connected flat surfaces with a surface corresponding to each side, foldable to provide the assembled pylon,

Description

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This invention relates to a landing pylon or pylon useful for aiding night landing of helicopters or fixed wing aircraft but also useful as an emergency marker to be carried in ambulance, or other emergency vehicles.
By 'aircraft' herein I mean fixed wing aircraft. The invention generally relates to marking the landing area for a helicopter or aircraft and giving an indication of the desired approach path.
In this application designated surfaces of the pylon are reflectant and preferably 'retro-reflectant'. A 'retro-reflectant' surface is of course specially designed to reflect back a substantial portion of the incident light in the direction of the light source. It is important to emphasize however that an ordinary reflectant surface, not specially designed to be retroreflectant, still retro-reflects a material portion of the light back to the source. Where an ordinary reflectant surface is used with the invention herein it is such retro-reflected material portion which is visible to the aircraft or helicopter operator.
The invention comprises means to provide an upwardly extending column defining a vertical axis. The column will be laterally defined by a plurality of outwardly facing upwardly extending surfaces which are highly reflectant and preferably retro-reflectant.
In one preferred aspect of the invention the surfaces will be designed, when the axis is vertical to slope at 3° - 10°

4 r to the vertical. The range includes the sub-range of 8° - 10° to the vertical in accord with the fact that the preferred angle of approach of a helicopter to a landing area is along a path about 9° to the horizontal and the sub-range of 3° - 6° to the vertical to correspond to aircraft approach angles of 3° - 6° to the horizontal. It is understood that the helicopter or aircraft will be provided with lights and a search-light adapted to project a beam along its approach path so that the helicopter or aircraft pilot will receive a brighter reflection when located on the desired approach path than when the helicopter or aircraft is located above or below the said path.
The side surfaces are collectively arranged in a flat blank with the side edges of adjacent side surfaces hingedly connected; with the side surfaces at each end of a connected group being detachably hingedly connectible to each other. Constructed in this way the surfaces may be folded at each hinged connection at equal angles to form the pylon. For storage or transportation this pylon may have the detachable connection disconnected and be unfolded flat for convenient stacking.
In its form as a flat blank the pylon is useful for carrying by ambulances or other emergency vehicles where it will have many uses in addition to those as a landing pylon. In such emergency vehicles there is qualities of compact storage and transportation are of considerable importance.
The preferred means and method of constructing the connected panels is by constructing them of molded plastic with a hI
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'l,m_ing hinges' that is the side surfaces with connecting thin films or skins of the same plastic material are molded in a single molding operation with the free edge connecting means also formed integrally and in the same molding step. With this arrangement the convenience of compact stacking is combined with efficiency of manufacture.
The arrangement described in the two previous paragraphs is preferably arranged, for aircraft or helicopter landing, to provide, in erected attitude, the desired surface sloping angles of 8° to 10°
or 3° to 6° previously described and will preferably have four sides arranged to form a square in section.
The arrangement described in the three previous paragraphs may preferably be provided with a top panel, also reflectant, and preferably retro reflectant hingedly connected to the top edge of one of the side surfaces and connectable (preferably by integrally molded means) with the top edges of the other side surfaces to form an k_ Cy; ~~ ~~ t ' ew c~ t ed v ~.s upwardly reflecting top panel in erected attitude.
With a plastic construction each alternative may be provided with metal weighting means, attachable after molding or molded in as part of the molding process.
With each alternative, means may be provided to support the pylon above ground surface for better visibility (for example -deep snow).
A plurality of such pylons arranged in a suitable pattern may be used to delineate a landing area or strip in remote areas which include: national or provincial parks, lumber camps, remote villages, the grass area in a highway clover-leaf or beside a highway.
To assist helicopter landing, an array of the pylons will usually be used to define a square of desired area, for example, it is desirable to use (for example) 16 of such pylons to define the outside boundaries of a square of (for example) 86' per side.
The pylons will customarily be separated approximately 20'. A
circular array will sometimes be used.
In its preferred form, the pylon is square in any horizontal section. Thus 16 such square-plan pylons for a helicopter, are preferably arranged at the corners and equally spaced along the sides of an 86' square with the four sides of the pylon (in plan) parallel and perpendicular to the side of the square formed by 16 of them. For an aircraft strip the pylons may be arranged in two rows to border the strip.
It is not thought necessary to provide internal levelling means for pylons. These in one aspect of the invention are a ~:' ~_x ' j ~:.~' ;.
preferably each provided with a bubble level mounted to indicate deviation from a level position and when a level position is achieved. In the level position, the pylon "vertical" axis will be truly so. Each pylon is thus placed in location on the field at the landing area and shimmed or adjusted by objects placed beneath its base until level attitude is achieved.
In a preferred form of the invention the pylon is formed as a hollow container so that it may be filled or partially filled with ballast to weight it in place.
In a preferred form of the invention the top of the pylon is designed to be perpendicular to the vertical axis and to provide a highly reflectant (preferably retro-reflectant) surface, preferably of different colour to the side wall surfaces, directed upwardly and providing an indication to a helicopter pilot (to a downwardly directed light) that he is "hovering" over the landing area. It may be desirable in some instances to provide that opposite reflecting side walls of the pylon are of different colours so that a row of pylons may be arranged to indicate which is the inside and which is the outside of a defined square area.
The side surfaces are provided in a flat blank wherein side surfaces are collectively arranged in a flat blank with the side edges of adjacent side surfaces hingedly connected with the side surfaces at each end of connected group being detachably hingedly connectible to each other. Constructed in this way the surfaces may be folded at each hinged connection at equal angles to form the pylon. For storage or transportation this pylon may J :.' ..~ ~3 <.i have the detachable connection disconnected and be unfolded flat for convenient stacking. Thus the pylon assembled from the blank may be particularly useful for transport in emergency vehicles, and when used other than for landing may have different angles of slope.
The preferred means and method of constructing the connected panels is by constructing them of molded plastic 'living hinges' that is the side surfaces with connecting thin films or skins of the same plastic material are molded in a single molding operation with the free edge connecting means also formed integrally and in the same molding step. With this arrangement the convenience of compact stacking is combined with efficiency of manufacture.
The alternate arrangement described in the two previous paragraphs is preferably arranged to provide, in erected attitude, the desired surface sloping angles 3° - 10° including the sub-range of 8° to 10° or 3° to 6° previously described and will preferably have four sides arranged to form a square in section.
The alternate arrangement described in the three previous paragraphs may preferably be provided with a top panel, also reflectant, and preferably retroreflectant hingedly connected to the top edge of one of the side surfaces and connectable (preferably by integrally molded means) with the top edges of the other side surfaces to form an upwardly reflecting top panel in erected attitude.
With a plastic construction each alternative may be provided with metal weighting means, attachable after molding or molded in as part of the molding process.

w With each alternative means may be provided to support the pylon above ground surface for better visibility (for example -deep snow).
In drawings which illustrate a preferred embodiment of the invention:
Figure 1 is a perspective view of a pylon, Figure 2 is a schematic view showing a preferred arrangement of the pylons to define a landing spot, Figure 3 is a side view of a pylon showing the approved angle of a helicopter approach path, Figure 4 shows the means allowing the filling of a hollow pylon with ballasting, Figure S shows the detachable bottom for the pylon, Figure 6 shows a blank for the invention, Figure 7 is an enlarged sectional view along the line 7-7 of figure 6, Figure 8 is a perspective view of the erected attitude of the blank of figure 6, and Figure 9 is a sectional view taken along the lines 9-9 of figure 6.
Figures 10-12 show the schematic arrangement of retro reflectant zones on a sheet, Figure 1-5 show and the accompanying description describes a pylon its shape and disposition which may or may not be made of the collapsible type forming this invention, Figures 6-9 and the accompanying description show the preferred construction of the collapsible pylon of this invention.

In the drawings the pylon 10 comprises a base 12 having four symmetrically arranged upward-inwardly sloping side walls 15 extending upwardly therefrom but preferably inset from the outer edges of the base to provide a sill 14. The pylon is preferably symmetrical about a vertical axis. The sloping side walls for helicopter use are defined by planar outwardly facing surfaces sloping outwardly between 8° and 10° (preferably 9°) to the vertical ~.i~ ~'~5 ~q-axis. For aircraft the side walls will slope at 3° - 6° to the vertical axis. A cap 16 covers the upper edges of the side walls and extends slightly outwardly therefrom to prevent rain and dust from getting into the inside of the pylon which is preferably hollow as hereinafter described. The cap has four peripheral surfaces 18 sloping inwardly at about 45° to the horizontal, bordering a horizontal upwardly facing square surface 20.
The side walls and the upwardly square surface are designed to be reflectant and preferably retroreflectant and preferably to reflect most brightly to a helicopter or aircraft which is projecting its light perpendicular to the plane of a side wall, and to reflect to a substantial but lesser extent to a helicopter or aircraft shining its light obliquely on the surface.
Figure 3 shows a helicopter approaching at 9° to the horizontal and designed to have its light directed at 9° to the horizontal and in the travel direction of the helicopter so that the pilot will receive a brighter retro reflection than if he is above or below the 9° approach path or to the right or left of the perpendicular to the retro reflecting surface. Thus the pilot will be warned that he is off path by the decreased retro reflected brightness.
Figure 1 shows a bubble level 22 designed to indicate when the vertical axis of the pylon is truly vertical. Thus with the pylon in place shims or supports are located and adjusted under the base until the bubble is centered indicating that the axis is vertical. The bubble level may preferably be located midway along a side of sill 14.
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Sill 14 is preferably provided with vertical mounting holes 23 at each corner. Holes 23 may be used to mount the pylon on a concrete slab or otherwise anchor it.
Figure,4 shows that the device may be made a hollow container and filled with ballast to hold it in place. The opening for filling may be provided in any of a number of different ways and one way is having the cap 16 removable as shown in Figure 4.
Preferably the upper surface 20 is made reflectant and preferably retro-reflectant but of a contrasting colour to the side walls so that the pilot (with a downwardly directed light) may tell when he is directly over an array of pylons. For such applications it is believed most effective to make the side walls of yellow reflectant material and the top wall of red reflectant material.
As Figure 5 shows the bottom 12 may be made detachable from the four side walls 15 which side walls form a single unit.
The bottom 12 may be made detachably attachable in any desired manner. Figure 5 shows a base 12 provided with L-shaped flanges which rest inside the corners of the side walls and hold them 20 in place. Bolts or screws may be used to attach the flanges to the side walls if desired. For packing and transportation therefore the bottoms 15 may be removed from the side walls and separately stacked while the side wall assembly may be conveniently and compactly nested.
In Figure 2, sixteen pylons 10 are shown defining a square preferably 86' with pylon spacing of approximately 20'. If desired and as shown three or more extra pylons l0E may be provided _g_ lttesding into the centre of one side of the square and thus indicating the desired approach direction. In some cases a second row of pylons 10E may be provided leading out of another side of the square. This arrangement would be suitable where the entrance and exit paths for a helicopter are to be different. In such case each row 10E of pylons would have distinctively coloured reflectant material on opposite sides facing toward and away from the desired travel direction to indicate it to the pilot.
As shown the pylons 10 are oriented in the array so their side walls are (in section) perpendicular to and parallel to the square sides. If desired opposite~pylon walls may have opposite coloured reflectant material to distinguish between the inside and outside of the array or between a desirable and undesirable approach direction.
In operation the pylons are preferably arranged as shown.
The side surfaces are designed to give lesser reflections to a helicopter located above, below or to the side of the perpendicular to the surfaces plane but the lesser reflections are designed to be sufficient to allow the pilot to locate the array. Having located the array, the pilot descends and locates his craft until the brighter reflection tells him that he is on the 9° flight path. He then descends on this flight path to landing. In addition a hovering helicopter with a vertically directed light can determine when it is directly over the array because of the brighter reflection,from the top surface 20.
Although not shown it is understood that, for aircraft use, the pylons with 3° - 6° side wall slope will be arranged in two _g_ li ~ on opposite sides of the desired landing path and may be differently coloured on opposite sides to indicate the desired landing and take-off directions.
The pylons may be made of any material, but ultra violet stabilized plastic is preferred. The reflectant and preferably retro-reflectant surface may be laminated on the outside of a top or side wall in any desired manner.
The preferred qualities and type of the retro-reflectant material are described hereafter in connection with Figure 10, 11 and 12.
Figures 6-9 show the blank of the invention wherein the four side walls 115 are defined by side edges 116, top edge 118 and bottom edge 120 and arranged to be made of molded plastic in a single molding step. In the flat blank the middle side walls 115M are each joined to the adjacent side wall at initially adjacent side edges by a thin film or skin 122 of the same plastic forming the side wall, known as a "living hinge" and molded with the four side walls in a single molding step.
In the flat blank the outer side walls 115E are joined to the adjacent wall 115M by a living hinge 122 as described and form as shown in Figure 8 a pylon body 110 geometrically similar to that of body 10 of Figure 1. The panel walls are covered with a preferred reflectant material 121, preferably laminated on as described hereafter.
The angle selected for the sloping side will be less than 20° and for the use described for the ap~r~ication of Figures 1-5 the sloping sides will define an angle of 8° - 10° or 3° - 6° for use in landing helicopters or fixed wing aircraft, respectively.
A top panel 134 may be hinged by a "living hinge" 136 to one of the panel 115 top edges. For ease of construction and use it is preferred to hinge the top panel to one of the end panels 115E
above. The free side edges 116E of the side walls 115E are provided with mutually cooperating hinged connection means for hingedly connecting these side walls in the erected position of the pylon.
These mutually cooperating means may be of any desired form but I
prefer to use one (or more) tabs 124 connected to the free side edge of one of the walls 115E by a living hinge 122 and a strip 128 with a complementary slot 130, the strip being connected to the other side wall by a living hinge 122.
Thus the blank as (partially) described so far may be erected by folding the four side panels so that each is at the same angle to its neighbour panel with tabs) 124 inserted in slots) 130. In erected form therefore with the folded panels so hinged the top panel and each of the top edges of the other three sides are provided with complementary tabs and slot strips with living hinges 122 similar in arrangement and use to those on the side panels.
Thus when the blank is folded for erection the top panel is attached to the side top edges (Figure 8) a pylon very similar except for the levels 18 to the pylon of Figure 5 is provided. The top panel will be laminated with reflectant material and the provision of selected colours on the sides. The attached top panel 134 may be omitted a separated top 20 may be provided as with the embodiment of Figures 1-5.

A bottom 131 connected by living hinging 122 and tabs, in a similar man't~"er to the top, may be provided and is shown However in many applications it may be preferred to have an open bottom.
With an open bottom the pylon folded from a blank may be provided with the detachable bottom shown in Figure 5.
The pylon of Figure 6 to 9 may be provided with weight bars 133 attached to the inside of the side panels near to their lower edges. Such bars will customarily be made of iron or steel and may be molded into the panels during the single molding process.
Alternatively 'keepers' of plastic may be formed in the side wall panels during the molding process adapted to detachably receive the weighting bars put in place with the pylon erected.
In operation, the pylon blanks of Figures 6-9 may be compactly stored or transported in flat attitude. For use each pylon is erected by applying weights, if not already in place, folding the sides and attaching the free edges and folding the top into place. The erected pylons will preferably be arranged as shown and described in connection with the embodiment of Figures 1 - 5 with particular reference to Figures 2 - 3. They will be designed for helicopter or fixed wing aircraft approaches, as previously described.
The pylon Figures 6 to 9 may be provided with leveling means if desired. For example two adjacent side panels may be molded each to support a level so that the two levels together will indicate a level attitude in the pylon.
If desired the pylons may be molded to receive support stakes so that the pylons may be supported clear of the ground for better visibility - for example in drifting snow.

~'~~4_ Although the most common application of the invention will be to use the pylons in square, circular or other array, the pylons may be used singly, where desired.
As previously stated, the pylon of Figures 6-9 is useful for other purposes than for landing aircraft or helicopters.
Thus it may be carried in emergency vehicles for any use to which a reflectant pylon could be put and where its flat blank form for storing and transportation is a great advantage over prior pylons or markers. When used for other purposes than landing helicopters or aircraft the pylon may have any slope to its sides although they will preferably slope at less than 20°.
The preferred retro-reflectant material for being laminated onto or otherwise placed on the pylon, will now be described.
The invention preferably makes use of surfaces made up of cube corner reflectors as described in the following U.S. Patents .
2,380,447 Jungerson 3,712,706 Stamm 3,684,348 Rowland 3,810,804 Rowland 4,025,159 4,202,600 Burke In particular the invention preferably makes use of cube corner ref lective sheeting as described in the Burke Patent 4,202,600 where regular arrays of cube corner sheets are arrayed in zones (indistinguishable to the user) oriented relative to adjacent zones in ~ich a way that retroreflective intensity variation with azimuthal angle is reduced at high angles of incidence to the normal to the sheet.
By an array is meant an ordered group of cube corner triads.
A 'zone' is the area occupied by such an array.
The invention takes advantage of the fact that retroreflectant material composed of arrays of cube corner reflectors (which are not individually distinguishable at minimum expected viewing distances) customarily retroreflect incident light more strongly at a normal angle of incidence and at an angle of incidence at 60° to the normal than at angles in between. It is sometimes convenient herein to refer to retroreflection along the normal as primary reflection and retroreflection at 60° to the normal as a secondary reflection.
It is noted that with all cube corner reflector arrays there is some directivity in the strength of the secondary reflection. That is for a given array zone the secondary reflection will be stronger in some azimuthal directions relative to the normal than others. This is of course more noticeable with a single array where all triads have an ordered orientation relative to each other. It will also be noted that the cube corner reflector array zones which are taught by Patent 4, 202, 600 and preferred for use with the invention, are too small for resolution by the viewer so that the actual orientation of individual zones of the reflecting surface is not known when a sheet bearing the reflectant coating is applied. Thus it is preferable if the cube corner reflector sheet is divided into zones (indistinguishable at usual viewing distances) which are differently oriented relative to each other tending to give a more uniform reflection at large angles to the normal and at varying azimuthal angles about the normal.

Preferably the cube corner cavity material is that sold under ~....
the trade mark REFLEXITE, a product of the Reflexite Corporation of New Britain, Connecticut. In such product the cube corner cavities are arranged in windows formed by triads of mutually perpendicular cube faces in an ordered array with a predetermined orientation. Such ordered arrays are in zones small enough to be indistinguishable to the viewer at minimum normal viewing distances. The zones are preferably arranged to have two orientations at 90° to each other arranged in a checkerboard or other pattern. The characteristics of the ordered array is to give stronger secondary reflections at 60° angular azimuth intervals and the result is that the 90° rotation between adjacent zones achieves an effective 30° rotation giving stronger azimuthal reflectivity at 30° intervals but relatively similar reflection intensity at angles in between.
Figures 10-12 are taken from U.S. Patent 2, 202, 600 previously referred to. In Figure 10 the preferred retroreflective sheeting is schematically illustrated from the non-retroreflecting side. The array as oriented in Figure 10 may be thought of as having an orientation corresponding to a horizontal directional arrow. As stated in Patent 4, 202, 600 the orientation of an array with an orientation as shown in Figure 10 can be varied in a regularly alternating pattern, such as a checkerboard pattern, in a random pattern or in any other pattern that provides sufficient mixing of different orientations to give the sheet an appearance of uniform brightness when viewed at a high angle of incidence from the minimum.
Figures ll andl2 show two preferred methods of combining arrays in zones with orientations at 90° to each other. Since the arrays have 60° symmetry (90° - 60° - 30°) each zone has its cube corner reflectors ~~'~~8~-or rated at 30° to adjacent zones. The result is reflective sheeting which for retroreflected rays at 60° to the normal, has relatively even reflectivity at different azimuthal angles about the normal.
As previously stated the preferred sheeting having the arrangements of Figures ll or 12 is Reflexite, AP1000 of the Reflexite Corporation of New Britain Connecticut. The zones are indistinguishable at normal minimum viewing distance.

Claims (10)

1. Collapsible landing pylon comprising at least three connected flat panels each having a pair of side surfaces, and each panel being hingedly connected to an adjacent panel at each hinged connection, and means for connecting the free side edges of the two end panels, said panels being shaped and hinged so that said free side edges are connected, and when said pylon is erected by then folding each panel at the same angle to its connected panel to form, a landing pylon defining a vertical axis, and an upwardly extending column being defined by said folded side surfaces sloping inwardly and upwardly, said surfaces each malting an angle of 3° - 10° with said central axis, said flat surfaces being adapted to be reflectant and to provide a higher degree of reflection at reflection angles equal and opposite to the angle of incidence and substantial but lesser reflection at other angles.

2. Collapsible pylon as claimed in claim 1 wherein the angle of the sloping sides surfaces to the central axis is 3° to 6° or 8° to 10°.

3. Collapsible pylon as claimed in claim 1 wherein the landing pylon has four such flat surfaces, arranged to define a square in horizontal section.

4. Collapsible pylon as claimed in claim 2 wherein the landing pylon has four such flat surfaces, collectively arranged to define a square in horizontal section.

5. Collapsible pylon as claimed in claim 2 constructed of molded plastic with integrally molded hinges and designed to be coupled to weighting means when erected.

6. Collapsible pylon as claimed in claim 4 constructed of molded plastic with integrally molded hinges and designed to be coupled to weighting means when erected.

7. Collapsible pylon as claimed in claim 2 wherein said side surfaces have parallel upper and lower edges and a top panel having a reflectant outer surface is hingedly connected to one of said upper edges, shaped to substantially meet said other upper edges when folded to be perpendicular to said central axis, means on said top panel for connecting said panel to each of said other upper edges.

8. Collapsible pylon as claimed in claim 4 wherein said side surfaces have parallel upper and lower edges and a top panel having a reflectant outer surface is hingedly connected to one of said upper edges, shaped to substantially meet said other upper edges when folded to be perpendicular to said central axis, means on said top panel for connecting said panel to each of said other upper edges.

9. Collapsible pylon as claimed in claim 5 wherein said side surfaces have parallel upper and lower edges and a top panel having a reflectant outer surface is hingedly connected to one of said upper edges, shaped to substantially meet said other upper edges when folded to be perpendicular to said central axis, means on said top panel for connecting said panel to each of said other upper edges.

10. Collapsible pylon as claimed in claim 6 wherein said side surfaces have parallel upper and lower edges and a top panel having a reflectant outer surface is hingedly connected to one of said upper edges, shaped to substantially meet said other upper edges when folded to be perpendicular to said central axis, means on said top panel for connecting said panel to each of said other upper edges.