U.S. patent application number 16/576171 was filed with the patent office on 2020-01-09 for tubular mast assembly, related kit, and methods.
The applicant listed for this patent is RTL Materials Ltd.. Invention is credited to Andrew Daton-Lovett, Richard Wood.
Application Number | 20200011083 16/576171 |
Document ID | / |
Family ID | 58688397 |
Filed Date | 2020-01-09 |
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United States Patent
Application |
20200011083 |
Kind Code |
A1 |
Daton-Lovett; Andrew ; et
al. |
January 9, 2020 |
TUBULAR MAST ASSEMBLY, RELATED KIT, AND METHODS
Abstract
A connector element for a tubular mast assembly, a tubular mast
assembly and a kit therefore, methods of assembling and
disassembling, a guide device and a spreader are provided. In an
aspect, a tubular mast assembly comprises first and second members
each comprising a shell resiliently biased in the form of an
elongate tube having longitudinal edges defining a slit along its
length. A connector element comprising a first socket receives an
end of the first member and a second socket receives an end of the
second member so as to connect the first and second members into an
extended tubular form. Each member can be disconnected from its
socket and its shell opened out at the slit to assume a flattened
form in which it can be wound into a coiled form for stowing the
assembly.
Inventors: |
Daton-Lovett; Andrew;
(Lymington, GB) ; Wood; Richard; (Lymington,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RTL Materials Ltd. |
Lymington Hampshire |
|
GB |
|
|
Family ID: |
58688397 |
Appl. No.: |
16/576171 |
Filed: |
September 19, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/GB2018/050539 |
Mar 2, 2018 |
|
|
|
16576171 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E04H 15/60 20130101;
E04H 12/342 20130101; E04H 12/02 20130101; E04H 12/2238
20130101 |
International
Class: |
E04H 12/34 20060101
E04H012/34; E04H 12/22 20060101 E04H012/22; E04H 15/60 20060101
E04H015/60 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 20, 2017 |
GB |
1704370.4 |
Claims
1. A tubular mast assembly comprising: first and second members
each comprising a shell resiliently biased in a form of an elongate
tube having longitudinal edges defining a slit along its length;
and, a connector element comprising a first socket which receives
an end of the first member and a second socket which receives an
end of the second member so as to connect the first and second
members into an extended tubular form, wherein each member can be
disconnected from its socket and is constructed and arranged such
that the shell can be opened out at the slit to assume a flattened
form in which it can be wound about an axis extending transversely
to its longitudinal direction to assume a coiled form for stowing
the tubular mast assembly.
2. The tubular mast assembly of claim 1, wherein each member
exhibits bi-stability in its coiled and extended forms.
3. The tubular mast assembly of claim 1, comprising a second
connector element comprising a first socket and a second socket,
wherein the first socket of the second connector element receives
an end of the first member that is opposed to the end of the first
member that is received in the first connector element, and wherein
the second socket of the second connector element is adapted to
provide a first foot element at an end of the second connector
element for supporting the tubular mast assembly on an object or on
the ground.
4. The tubular mast assembly of claim 3, wherein the second socket
of the first connector element further has a second foot element,
such that the first connector element and second connector element
are interchangeable in the tubular mast assembly in that they are
both able to provide a foot element to support the tubular mast
assembly and both able to connect the first and second members.
5. The tubular mast assembly of claim 4, wherein the first sockets
of the first and second connector elements further provide
respective third foot elements.
6. The tubular mast assembly of claim 3, wherein the first foot
element comprises a ring shape, castellated surface surrounding the
second socket for gripping an object or surface.
7. The tubular mast assembly of claim 3, wherein the first foot
element comprises a rubber or high friction material surrounding
the second socket for gripping an object or surface and/or for
gripping a member inserted in the second socket.
8. The tubular mast assembly of claim 1, wherein at least one
member is biased in the form of a tube having an external diameter
larger than an internal diameter of the corresponding socket in
which it is received, wherein when received in the corresponding
socket, the tube is compressed against the bias of the tube to fit
in the socket.
9. The tubular mast assembly of claim 1, wherein the connector
element has projecting features inside each socket for guiding at
least one edge portion of its member when it is inserted into the
corresponding socket, and/or for interacting with the edge portion
when fully inserted into the corresponding socket to help retain
its member in place.
10. The tubular mast assembly of claim 1, wherein the connector
element comprising a tubular sleeve and at least one stop element
fixed within the tubular sleeve, wherein one or both sockets are
defined by an open end of the tubular sleeve and the stop element
such that a leading edge of the corresponding member when fully
inserted into the or each socket abuts the at least one stop
element.
11. The tubular mast assembly of claim 10, wherein the tubular
sleeve is corrugated in profile, wherein the stop element is
engaged with corrugations in the tubular sleeve.
12. The tubular mast assembly of claim 10, wherein the stop element
is fixed by at least one fastener that passes through a hole in the
tubular sleeve and clips to the stop element.
13. The tubular mast assembly of claim 10, wherein the tubular
sleeve comprises a plastics material, and at least one member has a
foot element comprising plastics material, wherein the foot element
is adhered or welded to the tubular sleeve.
14. The tubular mast assembly of claim 1, wherein the tubular mast
assembly comprises three or more members joined by connector
elements.
15. The tubular mast assembly of claim 1, comprising a support
element fixed to a free end of one of the members that is not
inserted into one of sockets of a connector element, the support
element being adapted to support a load.
16. The tubular mast assembly of claim 15, wherein the support
element comprises a third socket for receiving the free end of one
of the members.
17. The tubular mast assembly of claim 15, wherein the support
element comprises fixtures for attaching tethers to tether the
tubular mast assembly in a deployed position.
18. The tubular mast assembly of claim 15, comprising a flexible
sheet or netting supported by the tubular mast assembly, wherein
the support element is a spreader element comprising a surface
having an increased cross sectional area relative to the members
and gripping elements or surface treatment for gripping the
flexible sheet or netting.
19. The tubular mast assembly of claim 18, wherein the gripping
elements comprise a plurality of blunt cylindrical studs extending
from the surface of the spreader element.
20. The tubular mast assembly of claim 1, wherein the members are
reversibly received in the sockets permitting disassembly of the
tubular mast assembly by withdrawing the members from the
sockets.
21. A tubular mast assembly in a kit form, the kit comprising:
first and second members each comprising a shell in a coiled form
in which the shell has a flattened form and is wound about an axis,
wherein each shell is configurable between its coiled form and an
extended form in which it is resiliently biased in a form of an
elongate tube extending transversely to the axis having
longitudinal edges defining a slit along its length; and, a
connector element comprising a first socket for receiving an end of
the first member and a second socket for receiving an end of the
second member, so as to connect the first and second members into
the tubular mast assembly.
22. The tubular mast assembly in the kit form of claim 21, further
comprising a guide device, the guide device comprising: a base; a
concave portion conforming generally to a curved surface of a
coiled portion of the first or second member, wherein the concave
portion has a low friction surface such that with the first or
second member being in a partially extended state, having a coiled
portion and an extended portion, with the coiled portion received
in the concave portion of the guide device, a force applied on the
extended portion towards the concave portion causes the coiled
portion to rotate against the low friction surface thereby
progressively adding the extended portion to the coiled
portion.
23. The tubular mast assembly in the kit form of claim 21,
comprising a container in which the kit form is stowed, wherein at
least one part of the kit form at least partly occupies a space
defined inside an interior coil of at least one member.
24. A connector element, comprising: a body comprising first and
second sockets constructed and arranged to receive tubular elements
so as to connect together the tubular elements into the tubular
mast assembly, wherein at least the first socket is additionally
constructed and arranged as a foot element adapted to interface to
the ground or another object on which the tubular mast assembly is
to be supported, such that where the second socket receives a
tubular element and the first socket does not, the foot element is
accessible at an end of the tubular mast assembly to provide
support to the tubular mast assembly, such that where a plurality
of connector elements are supplied in a kit, the connector elements
is selectively used to connect together tubular elements and to act
as the foot element.
25. A connector element according to claim 24, wherein the foot
element comprises one or more of: a ring shape encircling the first
socket; projections or an uneven surface arranged to provide
increased traction on the ground or the another object; a fastener
for attaching the foot element to an object or surface; and a
rubberized or high grip surface for providing traction on the
ground or another object, wherein the rubberized or high grip
surface optionally extends to an inner surface of the first socket
to help secure a tubular element inserted into the first
socket.
26. A spreader for supporting a flexible sheet or net, comprising:
a socket for receiving an end of a tubular member; the spreader
having a greater surface area than that of the end of the tubular
member; and, a plurality of blunt, cylindrical studs on a surface
of the spreader.
27. A guide device, comprising: a base; a concave portion
conforming to a curved surface of a coiled portion of the first or
second member, wherein the concave portion has a low friction
surface such that with the first or second member being in a
partially extended state, having the coiled portion and an extended
portion, with the coiled portion received in the concave portion of
the guide device, a force applied on the extended portion towards
the concave portion causes the coiled portion to rotate against the
low friction surface thereby progressively adding the extended
portion to the coiled portion.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part filing under 35
U.S.C. .sctn. 111(a) of International Patent Application No.
PCT/GB2018/050539, filed Mar. 2, 2018, which claims the benefit of
British Patent Application No. 1704370.4, filed Mar. 20, 2017, each
of which is incorporated herein by reference in its entirety.
TECHNICAL FIELD
[0002] The present invention relates to a tubular mast assembly, a
kit for a tubular mast assembly, methods of assembling a kit to
form a tubular mast assembly and disassembling a tubular mast
assembly, to a connector element, to a guide device and to a
spreader.
BACKGROUND
[0003] It is known in general in various applications to employ
modular, multi-piece pole systems for supporting objects, flexible
sheets and netting and the like. Typically these might comprise
aluminum tubular pole elements where one end of a pole is adapted
as a socket to receive the end of another pole, allowing the poles
to be fastened together to create a longer pole. For instance, in
some systems, two pole elements of approx. 1.3 m (4 feet) length
may connect together to form an approx. 2.6 m (8 feet) pole for
supporting a canvas or other structure. FIG. 1 for example shows
plural poles 1 formed from two pole structures 2a,2b joined
together 3 to support camouflage netting 4 which is tethered to the
ground 5. While these systems can perform adequately for some
applications, they generally tend to be overly heavy, bulky,
unwieldy and difficult to stow and deploy, as well as suffering
from undesirable material properties.
SUMMARY
[0004] The present invention aims to mitigate some or all of these
problem in known systems.
[0005] According to an aspect of the present invention, there is
provided a tubular mast assembly comprising:
[0006] first and second members each comprising a shell resiliently
biased in the form of an elongate tube having longitudinal edges
defining a slit along its length; and,
[0007] a connector element comprising a first socket which receives
an end of the first member and a second socket which receives an
end of the second member so as to connect the first and second
members into an extended tubular form,
[0008] wherein each member can be disconnected from its socket and
is constructed and arranged such that the shell can be opened out
at the slit to assume a flattened form in which it can be wound
about an axis extending transversely to its longitudinal direction
to assume a coiled form for stowing the assembly.
[0009] Thus a mast assembly can be formed from individual slit
tubular elements joined end to end in a structurally rigid form
using one or more connector elements. The mast assembly can be made
to different lengths and combined with other mast assemblies to
support flexible sheet materials such as netting, or other objects,
or in principle any application where a rigid elongate structure is
required. Thus, "mast" as used herein encompasses any boom, beam,
lever, rigid elongate member for supporting or positioning an
object, material, load, etc., or for actuation or anywhere where an
elongate structurally rigid member is required. The slit tubular
elements can be coiled when disassembled from the connector
elements for compact storage. Thus, a convenient and flexible
modular mast system is provided.
[0010] The tubular elements may be formed from a shell of plural
fiber reinforced layers in a laminate resiliently biased in a slit
tube form, but allowing the tube to be opened at the slit to a flat
profile for coiling. Preferably the shells allow progressive
coiling from one end and are reversibly configurable between coiled
and extended states.
[0011] In an embodiment, the or each member exhibits bi-stability
in its coiled and extended forms. Thus, the members may be coiled
for storage without needing external constraint to keep them in the
coiled form.
[0012] In an embodiment, the assembly comprises a second connector
element comprising a first socket and a second socket, wherein the
first socket of the second connector element receives an end of the
first member that is opposed to the end of the first member that is
received in the first connector element, and wherein the second
socket of the second connector element is adapted to provide a foot
element at the end of that connector element for supporting the
assembly on an object or on the ground. Thus, connector element has
a dual function in being able to connect two members together or to
connect to one, end member to act as a foot for adapting the mast
assembly to suitably interface with the ground or whatever surface
or object the mast assembly is to be deployed on. This simplifies
the elements that go into the mast assembly, leading to simpler
manufacturing and assembly/disassembly.
[0013] In an embodiment, the second socket of the first connector
element also has a foot element, such that the first connector
element and second connector element are interchangeable in the
assembly in that they are both able to provide a foot element to
support the assembly and both able to connect the first and second
members. Thus, the connector elements may be substantially
identical and both have dual functionality.
[0014] In an embodiment, the first sockets of the first and second
connector elements also provide respective foot elements. Thus, the
connector elements are effectively reversible, such that both ends
provide both functions, which again leads to simpler manufacture
and assembly/disassembly.
[0015] In an embodiment, the foot element comprises a ring shape,
castellated surface surrounding the second socket for gripping an
object or surface. Thus, the castellations, i.e. an uneven surface
with raised or projecting features, improves the ability of the
foot to grip the object or terrain on which the mast assembly is to
be deployed.
[0016] In an embodiment, the foot element comprises a rubber or
high friction material surrounding the second socket for gripping
an object or surface and/or for gripping a member inserted in the
second socket.
[0017] In an embodiment, at least one member is biased in the form
of a tube having an external diameter larger than the internal
diameter of the socket in which it is received, wherein when
received in the socket, the tube is compressed against the bias of
the tube to fit in the socket. Thus, the tubular member fits
tightly in the socket, helping prevent the tube from pulling out or
shifting in the socket.
[0018] The longitudinal edges of the slit tube subtend angle of
preferably at least 300 degrees and preferably less than 450
degrees. In embodiments the longitudinal edges of the slit tube
subtend angle of slightly less than 360 degrees (e.g. between 300
and 358 degrees, or more preferably between 340 and 358 degrees) to
leave a relatively small gap to aid compression. In other examples,
the member may subtend an angle of over 360 degrees to overlap the
edges (e.g. between 362 and 450 degrees). Nonetheless, the slit
tube may have edges that meet, in which case the user might
displace one edge relative to the other edge so that one passes the
other when the tube is compressed to insert it into a socket.
[0019] Optionally, in an embodiment, the connector element may have
projecting features inside the socket for guiding at least one edge
portion of its member when it is inserted into the socket and/or
for interacting with the edge portion when fully inserted into the
socket to help retain the member in place. For instance, the
connector element may have an internally tapering surface to guide
the edges of the member as they are inserted to the desired fully
inserted position. Optionally, the features may also interact with
the longitudinal edges of the slit to help hold the tubular member
in position in the socket.
[0020] In an embodiment, the connector element comprises a tubular
sleeve and at least one stop element fixed within the sleeve,
wherein one or both sockets are defined by an open end of the
sleeve and the stop element such that the leading edge of the
member when fully inserted into the or each socket abuts the at
least one stop element. The sleeve may be corrugated in profile.
This improves the bending strength of the member compared with a
cylindrical sleeve. The stop element keys with the corrugations in
the sleeve. For instance, the stop element has projecting elements
that extend into grooves of corrugation and help keep the stop
element in place.
[0021] In an embodiment, the stop element is fixed by at least one
fastener that passes through a hole in the sleeve and clips to the
stop element.
[0022] In an embodiment, the sleeve comprises a plastics material,
and at least one member has a foot comprising plastics material
adhered or welded to the sleeve. The rubberized surface may then be
over molded to the plastics material in the foot.
[0023] In an embodiment, the assembly comprises three, or four, or
five, or more members joined by connector elements.
[0024] In an embodiment, the assembly comprises a support element
fixed to a free end of one of the members that is not inserted into
a socket of a connector element, the support element being adapted
to support a load. For instance, the support element may grip, or
attach etc. or spread forces and transmit forces to members in
suitable way that does not damage the material. In an embodiment,
the support element comprises a socket for receiving the free end
of the member. Thus, the support element may attach to the tubular
members in a similar way to the way the connector element attaches
to the tubular members. The support element may further comprise
fixtures for attaching tethers to tether the assembly in a deployed
position.
[0025] In an embodiment, the assembly may comprise a flexible sheet
or netting supported by the assembly, wherein the support element
is a spreader element comprising a surface having an increased
cross sectional area relative to the members and gripping elements
or surface treatment for gripping the flexible sheet or netting.
The flexible sheet or netting may comprise a tent, canopy,
waterproof covering, antiradar or heat signature, or camouflage
netting or the like.
[0026] In an embodiment, the gripping elements comprise a plurality
of blunt cylindrical studs extending from the surface of the
spreader.
[0027] In an embodiment, the members are reversibly received in the
sockets permitting disassembly of the assembly by withdrawing the
members from the sockets. Preferably the members are held in the
sockets by a friction fit or the like, can be simply pulled out of
the socket manually without requiring tools.
[0028] In an embodiment, the connector element is sized to fit at
least partially in the space in the inner coil of a member. In an
embodiment, at least one coiled member is adapted to fit within the
coil of another member.
[0029] In embodiments, the tubular members, connector elements and
support elements may comprise substantially only plastics and
rubber materials and preferably at least no metal parts so as to be
radar invisible and safe from lightning strikes.
[0030] According to a second aspect of the present invention, there
is provided a kit for a tubular mast assembly, the kit
comprising:
[0031] first and second members each comprising a shell in a coiled
form in which the shell has a flattened form and is wound about an
axis, wherein each shell is configurable between its coiled form
and an extended form in which it is resiliently biased in the form
of an elongate tube extending transversely to the axis having
longitudinal edges defining a slit along its length; and,
[0032] a connector element comprising a first socket for receiving
an end of the first member and a second socket for receiving an end
of the second member so as to connect the first and second members
into a tubular mast assembly.
[0033] Thus, the assembly in kit form is compact and light for
storage and transportation, whilst being able to form a versatile
mast assembly, as described above. Different length members may be
provided, e.g. two lengths, allowing a large variety of different
assembled lengths to be achieved. For instance, small members
connected to large members can provide a number of equal, medium
length masts, whilst small members connected together and large
members connected together provides shorter and longer masts
allowing different mast lengths to be provided which may be useful
in some applications, e.g. for supporting different shapes of
netting or canopies to be supported, according to need. Slit
tubular members of different lengths may nonetheless have generally
similar sizes to each other when coiled, meaning that compact and
efficient packing of the kit is still possible.
[0034] The kit may comprise a container in which the kit is stowed,
wherein at least one part of the kit at least partly occupies the
space defined inside the interior coil of at least one member.
Thus, for instance, a connector element may be disposed in the
inner space of one or more coiled members. Alternatively or
additionally, a coiled member may be disposed in the inner space of
one or more other coiled members. The diameters of the various
elements may naturally be non overlapping, i.e. the outer diameter
of one element is smaller than the inner diameter of the coil in
which it is to be stowed, such that the element can simply be
inserted. Alternatively, the inner element may act as a bobbin on
which the outer coil can be wound, so hold the outer open to the
necessary extent. This allows very dense, compact packing of the
elements of the kit which is a significant advantage to the
arrangement of the mast assembly kit as separate connector elements
and coiled members.
[0035] According to a third aspect of the present invention, there
is provided a method of assembling a kit to form a tubular mast
assembly, the method comprising:
[0036] uncoiling first and second members, each member comprising a
shell in a coiled form in which the shell has a flattened form and
is wound about an axis, wherein each shell is uncoiled into an
extended form in which it is resiliently biased in the form of an
elongate tube extending transversely to the axis having
longitudinal edges defining a slit along its length;
[0037] inserting an end of the first member into a first socket of
a connector element; and,
[0038] inserting an end of the second member into a second socket
of a connector element so as to connect the first and second
members into a tubular mast assembly.
[0039] The method may comprise connecting a second connector
element in the kit comprising a first socket and a second socket,
wherein an end of the first member that is opposed to the end of
the first member that is received in the first connector element is
inserted into the first socket of the second connector element, and
wherein the second socket of the second connector element is
adapted to provide a foot element at the end of that connector
element for supporting the assembly on an object or on the
ground.
[0040] The method may comprise connecting third or more members
with additional connector elements.
[0041] The method may comprise connecting a support element fixed
to a free end of one of the members that is not inserted into a
socket of a connector element, the support element being adapted to
support a load.
[0042] The method may comprise compressing an end of the member to
reduce its diameter before inserting it into a socket, and
releasing the member such that the diameter expands due to its
resilient bias to provide a friction fit in the socket. This
provides a simple, but secure way of connecting a tubular member
into a socket which can be accomplished manually without additional
tools.
[0043] The method may comprise supporting a load with the tubular
mast assembly. The load supported may be a netting or fabric or any
flexible material sheet, e.g. woven, knitted or braided, or an
object such as a camera, light, transmitter and/or receiver for
receiving signals. A support element may be provided at the distal
end of the mast adapted to support the load by way of fasteners,
clamps, etc.
[0044] The method may comprise disassembling the assembly, coiling
the members and stowing the kit.
[0045] The method may comprise stowing at least one component of
the kit within the inner coil of a coiled member.
[0046] Accordingly to a fourth aspect of the present invention,
there is provided a method of disassembling a tubular mast assembly
comprising:
[0047] first and second members each comprising a shell resiliently
biased in the form of an elongate tube having longitudinal edges
defining a slit along its length; and,
[0048] a connector element comprising a first socket which receives
an end of the first member and a second socket which receives an
end of the second member so as to connect the first and second
members into an extended tubular form, the method comprising
disconnecting each member from its socket, opening the shell of
each member out at the slit to assume a flattened form in which it
is wound about an axis extending transversely to its longitudinal
direction to assume a coiled form for stowing the assembly.
[0049] According to a fifth aspect of the present invention, there
is provided a connector element for a mast assembly kit, the
connector element comprising:
[0050] a body comprising first and second sockets constructed and
arranged to receiving tubular elements so as to connect together
the tubular elements into a mast assembly, wherein at least the
first socket is additionally constructed and arranged as a foot
element adapted to interface to the ground or another object on
which the mast assembly is to be supported, such that where the
second socket receives a tubular element and the first socket does
not, the foot element is accessible at the end of the mast assembly
to provide support to the mast assembly, such that where plural
connector elements are supplied in a kit, the connector elements
can interchangeably be used to connect together tubular elements
and to act as a foot element.
[0051] In an embodiment, the foot element comprises one or more
of:
[0052] a ring shape encircling the first socket;
[0053] projections or an uneven surface arranged to provide
increased traction on the ground or other object;
[0054] a fastener for attaching the element to an object or
surface; and
[0055] a rubberized or high grip surface for providing traction on
the ground or another object, wherein the rubberized or high grip
surface optionally extends to an inner surface of the first socket
to help secure a tubular element inserted into that socket.
[0056] According to a sixth aspect of the present invention, there
is provided a spreader for supporting a flexible sheet or net,
comprising:
[0057] a socket for receiving an end of a tubular member;
[0058] a spreader top surface having a greater surface area that
that of the end of the tubular member; and,
[0059] a plurality of blunt, cylindrical studs on the surface of
the spreader.
[0060] This allows materials and netting so be safely supported by
a mast formed from the spreader and tube by the increased surface
area of the spreader where the relatively blunt studs prevent the
netting or material from shifting after being thrown over the
spreader, and preventing damage to the material or netting or
coatings or other additives applied to the material or netting,
whilst allowing the material or netting to be simply removed when
disassembling the mast. Comparative technology in the prior art
relies on dense, pointed, "bristle-like" projections to snag the
fabric and retain it, at the cost of potentially causing damage to
the material and coatings that may be applied to it.
[0061] According to a seventh aspect of the present invention,
there is provided a guide device, the guide device comprising: a
base; a concave portion conforming generally to the curved surface
of a coiled portion of the first or second member, wherein the
concave portion has a low friction surface such that with the first
or second member being in a partially extended state, having a
coiled portion and an extended portion, with the coiled portion
received in the concave portion of the guide device, a force
applied on the extended portion towards the concave portion causes
the coiled portion to rotate against the low friction surface
thereby progressively adding the extended portion to the coil. The
invention also extends to a method of coiling an extendible member
by placing the coiled portion of a partially coiled member in the
concave portion and applying a force towards the concave portion to
cause the member to coil. The guide device is suitable for use with
the tubular mast assembly kit described above, and may speed the
process of disassembling the assembly for packing away. However,
the guide device is suitable for use with any slit tubular member
that is to be coiled.
[0062] The invention also extends to support elements having a
socket for receiving an end of an extendible member and at least
one of a clamp for a light fixture, a hook or other attachment
means for attaching to an object.
[0063] It will be appreciated that any features expressed herein as
being provided "in one example" or "in an embodiment" or as being
"preferable" may be provided in combination with any one or more
other such features together with any one or more of the aspects of
the present invention. In particular, the extendible member,
joining techniques and join testing system described in relation to
one aspect may generally be applicable to the others.
BRIEF DESCRIPTION OF THE DRAWINGS
[0064] Embodiments of the present invention will now be described
by way of example with reference to the accompanying drawings, in
which:
[0065] FIG. 1 shows an example of a prior art system for supporting
camouflage netting;
[0066] FIG. 2 shows an example of a kit for a tubular mast assembly
according to an embodiment of the present invention;
[0067] FIG. 3 shows an example of a tubular mast assembly according
to an embodiment of the present invention in which elements of the
kit shown in FIG. 2 have been assembled;
[0068] FIG. 4 shows an extendible member which may form part of the
kit of FIG. 2;
[0069] FIG. 5 shows a connector element which may form part of the
kit of FIG. 2;
[0070] FIG. 6 shows a cross sectional view of the connector element
of FIG. 5;
[0071] FIG. 7 shows a detail view of an example of a foot element
which may form part of the connector element of FIG. 5;
[0072] FIG. 8 shows a cross sectional view of the foot element of
FIG. 7 attached to the rest of connector element;
[0073] FIG. 9 shows an example of a stop element which may form
part of the connector element of FIG. 5;
[0074] FIG. 10 shows an example of a fastener for connecting the
stop element of FIG. 9 with the rest of the connector element;
[0075] FIG. 11 shows an example of a supporting member according to
an embodiment of the present invention, which may form a part of
the kit of FIG. 2;
[0076] FIGS. 12a and 12b show the kit of FIG. 2 packing into a
storage container; and
[0077] FIG. 13a shows a projection view of an example of coiling
guide device according to an embodiment of the present invention;
and
[0078] FIG. 13b shows in cross section an extendible member being
coiled by the coiling guide device of FIG. 13a.
DETAILED DESCRIPTION
[0079] FIG. 2 shows an example of a kit 10 for a modular tubular
mast assembly according to an embodiment of the present invention.
The kit 10 comprises plural elements including plural extendible
members 20, plural connector elements 40 and plural support
elements, in particular, spreader elements 80 in this example, for
supporting netting or other flexible sheet material or fabric.
[0080] FIG. 3 shows an example of a modular tubular mast assembly
11 constructed from elements of the kit 10 shown in FIG. 2. As will
be described in more detail in the following, the extendible
members 20 can be extended from a coiled configuration as shown in
FIG. 2 to an extended, slit tubular configuration. In this extended
configuration, a first member 20a is joined to a second member 20b
by a first connector element 40a. A second connector element 40b is
connected to the bottom end of the second member 20b and acts as a
foot for the assembly, supporting the assembly on the ground 12 or
some other object. The first end of the first member 20a is
connected to a spreader element 80, which is used to support
netting 13. Plural such tubular mast assemblies 11 can be
constructed from the kit 10 and used to support the netting 13. Guy
ropes or other tethers 14 may be attached to the spreader 80 or
connector elements 40 or some other convenient point on the
assembly 11 to stabilize the tubular support assembly 11. The kit
10 may comprise members 20 of more than one length when extended.
In principle, the kit 10 may comprise members 20 having more than
one diameter when extended, with connector elements 40 and
spreaders 80 adapted to fit each diameter.
[0081] FIG. 4 shows an example of an extendible tubular member 20
comprising a fiber reinforced shell 21. The member 20 can be
reconfigured between a coiled state 22 and an extended state 23,
via a transition stage 24. In the extended state 23 the member 20
is generally elongated and biased to have a curved or non-linear
cross section in a direction transverse to the longitudinal axis 25
of the member. (References to longitudinal axis or longitudinal
extent or direction of extension or retraction in this document
generally refer to this axis 25). Thus, the longitudinal edges 26
form a slit 27 in the generally curved, tubular form. This
curvature can be adapted and thus the cross section of the extended
portion can comprise anything from a closed or substantially closed
circular shape, or other generally closed shapes. The member 20 is
resiliently biased in this curved cross section when extended. This
gives structural rigidity to the member 20 when extended. In the
coiled state 22 the member 20 is generally opened out at the side
longitudinal edges 26 to have a flat cross section, and is coiled
around an axis 29 that is generally transverse to the longitudinal
axis 25 of the member 20.
[0082] The shell 21 is generally thin to aid coiling, e.g.
typically between 0.5 mm and 5 mm for most applications. Such
members are sometimes referred to as STEMs (Slit Tubular Extendable
Members).
[0083] Typical lengths of the extended members 20 may be between 1
m and 5 m and typical diameters may be between 5 cm and 15 cm. It
will be appreciated that in principle almost any length and
diameter can be used according to the application.
[0084] In the present example, the shell 21 may be formed from a
thermoplastic matrix with fiber reinforcements, such as a fiber
reinforced polymer ("FRP" hereafter). The fibers may be glass,
carbon, or aramid, while the polymer may be polypropylene,
polyethylene, a polyamide, polyester thermoplastic,
poly-ether-ether-ketone or any other polymer suited to the
particular requirements of the task at hand. The composite material
may comprise a single layer or plural layers with fibers oriented
in different directions in each lamina. The use of fibrous
materials mechanically enhances the strength and elasticity of the
plastic matrix. The extent that strength and elasticity are
enhanced in a fiber reinforced plastic depends on the mechanical
properties of both the fiber and the matrix, their volume relative
to one another, and the fiber length and orientation within the
matrix. FRPs are widely used in many areas such as aerospace and
automotive industries, and are not described in detail herein.
[0085] In the present example, the member 20 is a bistable reelable
composite (BRC). Such a bistable member has a first stable state in
the coiled form 22, where the cross section of the member 20 is
generally flat and a second stable state in the extended form 23,
where the cross section of the member is curved as previously
described. The bistable member 20 may be capable of reversible
configuration between its coiled and extended forms a plurality of
times. Suitable structures are disclosed in the following
international patent applications, each of which is incorporated
here by reference: WO88/08620A1, WO97/35706A1, WO99/62811A1,
WO99/62812A1 and WO2012/168741A1. Such bistable structures are
available from RolaTube Technology Limited of Lymington, the United
Kingdom.
[0086] In general, there are two ways to make a tube bistable:
either by altering the bending stiffness of the structure so that
it is no longer isotropic, for instance by using a fiber-reinforced
composite, or by setting up an initial prestress in the structure.
The BRC in the present example uses the first technique. This
involves arranging the fibers to increase the torsional stiffness,
and increase the coupling between bending in the longitudinal and
transverse directions.
[0087] Normally when something is bent the amount of energy stored
by that bending (the total strain energy) rises as the degree of
bending increases. In BRCs, once the initial curvature is
straightened as the tube is opened, the stiffness along the
longitudinal axis drops and the forces acting on the material of
the tube arising by the deformed surface layer fibers can act to
flip it into the coiled form. As this second curvature forms, the
total strain energy drops, thereby forming a second stable form, or
more stable form, for this section.
[0088] These principles operate in reverse when moving from the
coiled state to the extended state.
[0089] Thus, structural members are formed that exhibit a stable
geometry in both the extended and coiled states. These manage the
problems of difficult handling and complicated mechanisms by
forming STEM type structures from materials that have been
engineered so as to make them easy to coil and handle.
[0090] FIG. 5 shows a projection view and FIG. 6 shows a cross
sectional view of a connector element 40 comprising a corrugated
sleeve 42 with a foot piece 44 at each end. Fasteners 46 extend
through holes 47 in the wall of the sleeve 42 to fasten a stop
element 48 inside the sleeve 42 generally midway along the length
of the sleeve 42. The sleeve 42, stop element 48 and fastener
preferably are made from plastics material. The connector element
40 has a socket 41 at each end projecting through the foot piece 44
and into the sleeve 42. Each socket 41 is constructed arranged to
receive a member 20, which can be inserted until it abuts the stop
element 48. The sockets 41 are preferably relatively deep to
support the tubular members 20 and resist bending loading on the
mast assembly 11. For example, the sockets 41 may be at least as
deep as their width and in some examples will be at least twice as
deep as their width or more. The corrugated design give
considerably larger bending strength to the connector element,
thereby allowing the wall thickness of the connector piece to be
reduced and the product to be lighter.
[0091] The inside diameter of the socket 41 is preferably slightly
less than the unconstrained diameter of the extended tube, for
instance, the tube diameter may be 0.5% to 5% greater than the
socket diameter. Thus, to insert the member 20 into the socket, the
member 20 is first uncoiled to its slit tubular form and then the
end of the member is compressed by the user to reduce its diameter
against the residual bias of the member. The end of the member 20
can then easily be inserted into the socket 41. Once fully inserted
up against the stop element 48, the pressure can be released and
the tube will expand outwardly due to the resilient bias against
such that friction helps hold it in place against the interior
surface of the socket. The member 20 can be removed from the socket
41 using the reverse technique of compressing the end of the
member. The socket 41 may be arranged such that the member 20 can
be introduced in any circumferential orientation. The slit tube
member 20 may subtend an angle of slightly less than 360 degrees
(e.g. between 340 and 358 degrees) to leave a gap 27 to aid
compression. In other examples, the member 20 may subtend an angle
of over 360 degrees (e.g. between 362 and 450 degrees) to create
overlapping edges 26 to aid compression. Nonetheless, members with
edges 27 that meet will also work.
[0092] FIG. 7 shows a detailed view of the foot element 44 and FIG.
8 shows a sectional view of the foot element 44 attached to the
sleeve 42. The foot element 44 comprises a ring shape body 48 made
from ABS molded plastics over molded with a rubber outer portion 50
(shown in transparency in FIG. 7). When used as a foot, the rubber
portion 50 allows the connector element 40 to grip a surface or
object on which it is placed. The outward facing surface of the
foot has castellations 51 or some other uneven surface adapted to
allow the connector element 44 to grip the underlying surface or
object, such as when placed on sand, soil or other particulate
matter. The ring shape of the body 48 also allows the foot element
44 to encircle a protruding part of the underlying surface or
object, to again help retain the foot element 44 in place. The
weight of the mast assembly 11 or the netting 13 may be used to
keep the foot element 44 in contact with the surface. Alternatively
or additionally, tethers 14 or other fasteners may be used to
attach the mast assembly 11 to its surroundings.
[0093] The rubber portion 50 also extends onto the inner surface 55
of the ring shaped body 48 to help grip the member 20 inserted into
the socket 41. The plastics body has a groove 57 adapted to receive
the end of the sleeve 42 and may be keyed to the corrugations in
the sleeve. The foot element 44 may be glued or welded into
position on the sleeve end, or by using mechanical fasteners.
[0094] FIG. 9 shows the stop element 45 in more detail and FIG. 10
shows a fastener 46 for fixing the stop element 45 into the sleeve
42. The stop element 45 comprises a plastics body 60 having a
generally ring or disk shape to generally match the interior
profile of the sleeve 45 and the periphery of the body has
protrusions 61 which key it into the corrugations 53 in the
interior of the sleeve. The stop element 45 preferably has tapered
surface features 63 which help guide the leading edge of the member
20 into the fully received position where it abuts a generally
annular surface 62 at the periphery of the stop element 45. The
tapered surface may wedge the end of the tube against the interior
walls of the sleeve to help prevents it from moving. Thus, the
edges of the member 20, which are points particularly susceptible
to impact damage and other failure modes, are protected. In some
embodiments, further features of the body 45 may interact with the
longitudinal edge or edges 26 of the member 20 inserted in the
socket 41 to further support the tube and help prevent buckling,
rotation or twisting of the tube.
[0095] The fastener 46 comprises a plastics body having a head 70
portion and two reliantly biased legs 72 extending from the head
portion 70, each having a lug 74 on the end opposite the head
portion 70.
[0096] To manufacture the connector element 40, the stop element 46
is introduced into the sleeve 42 until holes 64 in the body 60
align with the holes 47 in the sleeve 45. The fasteners 46 are
inserted through the holes 47 from the outside of the sleeve 45.
The resilient legs 72 are compressed together allowing the
protruding lugs to pass through the hole, aided by the leading edge
of the lugs being tapered. When the fastener is fully inserted, the
head 70 lies against the surface of the sleeve 42 within a
corrugation preventing further ingress, and the lugs latch with the
far lip 66 of the hole 64 or a lip provided by a suitable recess in
the hole, thus securing the stop element 45 in place in the sleeve
41. The foot elements 44 are then attached to the ends of the
sleeve by gluing or welding them in place.
[0097] It will be appreciated that other construction techniques
can be used. For instance, other mechanical fasteners, i.e. a
threaded fastener or rivet, or glue could be used to attach the
stop element 46 to the sleeve 42 or the foot elements 44 to the
sleeve 42.
[0098] The connector elements 40 are preferably symmetric in
function such that each end can be used as a socket 41 for
receiving a member 20 or as a foot 44 to support the assembly 11.
The connector elements 40 thus have dual functionality in that they
can be used interchangeably as a foot, or to connect together
extendible members 20. This increases the versatility of the kit,
in that different configurations can be made. For instance, six
members 20 and six connector elements 40 can be configured as two
3-length mast assemblies 11 or as three 2-length mast assemblies
11. Compared with a kit, where different elements are used as the
connectors and the feet, to allow both mast configurations would
require three feet and four connector elements, i.e. seven
elements, compared with the six dual function elements 40 in the
present example. This saves weight and space. Furthermore, the
person assembling the kit 10 does not need to identify about which
item is which, or which end to connect to the tubular members.
Similarly, the members 20 are functionally symmetric, meaning that
the person assembling the kit 10 does not have to identify which
end is which. The dual function of the connector elements 40 also
simplifies manufacture, in that fewer molds, tooling, etc., are
needed.
[0099] FIG. 12 shows the spreader element 80 comprising a molded
plastics body 81,82 having a generally disc shape upper part 81
with a socket 82 below for receiving and connecting to a member 20.
The upper part 81 has a wider extent, e.g. approx. 30 cm in this
example, than the socket 82, approx. 7 cm in this example, to help
spread the load of the netting or material being supported, e.g.
between 2.times. and 10.times. the width of the socket 82 in most
envisioned applications. As described previously in relation to the
connector elements 40, the socket 82 is preferably slightly smaller
than the unconstrained diameter of the member 20 to help friction
grip the member 20.
[0100] The upper surface 81 of the body has a plurality of blunt
molded studs 86 extending from the surface. In the present example,
the upper part has cut-outs 84 to save weight. Thus, the body forms
a hub portion 87 with a first group of plural studs and a rim
portion 88 with a further group of studs connected to the hub by
spokes 89. The studs 86 may be arranged in a triangular pattern
relative to neighboring studs with further cut-outs between the
studs 86.
[0101] The studs 86 are preferably generally cylindrical or
frustroconical with little or no taper (e.g. less than 10 degrees
side slope to the direction of the stud 86). The end of the studs
86 are at least 1 mm wide and may be between 2 mm and 5 mm and be
raised from the surface by between 4 mm and 10 mm in typical
applications. The majority of studs 86 in any grouping of studs,
i.e. on the rim 88 or on the hub 87, may be separated from its
neighboring studs 86 by at least 10 mm and in some cases 20 mm or
more. Thus, relatively blunt, well separated studs 86 are provided.
It has been found that this arrangement is particularly useful with
supporting new lightweight, high-tech, nets, which are designed to
defeat a large range of sensors, e.g. radar, rather than just
providing visual cover or camouflage. This has been found to
support nets and other mesh fabrics with lower risk of damage to
the materials and their coating compared with comparative net
supports, which typically use a plurality of closely spaced,
pointed pegs. These "bristle" type peg features on the upper
surface engage with and prevent slippage of the nets, but are prone
to cause damage to the materials and their coatings. Existing
designs use pointed, raised features that are easy to throw a net
over and then position and re-position, as the net does not need to
be raised significantly to adjust it. The introduction of nets that
are both lighter and coated in various anti-detection agents has
shown that continuing this type of design damages the coatings and
can damage the nets themselves. By replacing the raised pointed
features with a solid stud of higher relief and without sharp
features prevents such damage by providing a solid location
point
[0102] In other examples, different support members 80 can be
provided to support different types of loads.
[0103] The mast assembly 11 may additionally comprise a hook, clamp
or other fixing means to allow further objects to be supported by
the mast assembly. These might be provided by a support element 80
or a connector element 40 or a separate member included in the kit
10 which connects to an extended member 20 in place of the support
member 80. For instance, a light may be supported by a mast
assembly 11 by replacing the spreader element 80 with a support
element adapted to supporting a light, or clamped in place by a
spreader element 80 or connector element 40 with an additional
light mounting fixture, or directly incorporated into those
elements to provide illumination under a canopy or the like
supported by the mast assembly 11.
[0104] A kit 10 for a tubular mast assembly 11 may comprise:--
[0105] 4.times. approx. 2.6 m (8 feet) long BRC tubes 20
[0106] 4.times. approx. 1.3 m (4 feet) long BRC tubes 20
[0107] 6.times. Support elements 80
[0108] 8.times. Connector elements 40
[0109] 24.times. Ground Stakes
[0110] 1.times. Bag or case 100
[0111] FIGS. 12a and 12b shows the kit 10 packed into case 100,
with FIG. 12a showing an exploded view of the different types of
element in their relative positions when packed and FIG. 12b
showing the final form of the packed kit in the case 100. The case
100 may have internal dividers or other structures 101 to form
different compartments in the case 100 for the elements of the kit
10. The case 100 may have pockets for stakes, tethers, etc. (not
shown) for supporting the erected assembly 10 and/or instructions
for assembly/disassembly.
[0112] At least one part of the kit 10 may pack at least partially
inside the space defined by the inner coil of a coiled member 20.
The coil can naturally have an inner diameter large enough to
accommodate the inner part. Alternatively, the inner part may act
as a bobbin on which the outer coil can be wound, and so hold the
outer open to the necessary extent.
[0113] For instance, at least one connector element 40 may be
positioned within the interior coil of at least one coiled member
20. It is expected that a convenient length for the connector
element 40 will be approximately twice the width of the coiled
member 20, meaning that the connector element 20 can be packed
within the interior space of two adjacent coiled members 20.
Furthermore, one coil may be disposed within another coil. For
example, one member 20 may form a tighter coil than another member
20 such that its outer diameter is less than the inner diameter of
the other member 20. This might occur where members 20 of two
different extended widths or lengths are provided. Alternatively or
additionally, the outer coil can be wound on the inner coil which
holds it open to the necessary extent. Thus, the less tightly
coiled member 20 may accommodate the more tightly coiled member 20
within the space of its interior coil, which may in turn
accommodate a connector element 40 within the space of its interior
coil.
[0114] FIG. 12a shows possible relative positions of the connector
elements 40 and of the coiled members 20 for packing within the
case 100. Thus, to take one example, it can be seen that coiled
members 20b are wound over coiled members 20a and placed adjacent
to each other, and connector member 40a will fit within the
adjacent coiled members 20a. These are positioned in compartment
102a next to the internal divider element. Three other connector
members 40b are also positioned in the compartment 102, leaving a
gap 40c. The spreader elements 80a,80b are positioned the upper
parts 81 above and below these connector members 40b with the
sockets 82 extending into the gap 40c. The arrangement is mirrored
in the other compartment.
[0115] Thus, a highly compact form of the kit 10 can be supplied,
in this case achieving a packed volume of approx. 0.82 m cubed (2.9
feet cubed), i.e. approx. width=91 cm.times.depth=56
cm.times.height=16 cm (36 inch.times.22 inch.times.6.5 inch). These
techniques can provide a packed volume of approximately 64% of
current modular pole systems comprising aluminum based pole
segments. It is expected that, were the packed volume is an
important consideration, even more compact packing can be achieved
using these techniques. The use of plastics materials in the mast
assembly can also result in significantly a lighter weight than
equivalent systems, up to approximately 20% lighter than
comparative systems.
[0116] The kit 10 is also simple to deploy and stow. The user can
simply uncoil the coiled members 20 into extended tubular members
20. To insert the extended member 20 into a socket 41,82 of the
connector element 40 or spreader 80, the user can squeeze the slit
tube causing a reduction in its diameter at the slit, allowing it
to be inserted into the socket of the member or spreader. The
pressure can then be released, allowing the tube 20 to expand
towards its normal diameter due to its internal bias, thus forming
a tight fit on the interior of the socket, which may be rubberised
to help grip the member 20. Thus, the masts 11 can be quickly and
conveniently assembled without tools. The spreader 80 and or
connector elements 40 may have a fixture for attaching tethers to
stake the mast 11 to the ground or tie the mast 11 to some other
feature.
[0117] To disassemble, the user would again compress the ends of
the tubular members 20, which due to the slit would become loose in
their sockets 41,82 so they can be removed and then coiled,
allowing rapid, tool-less disassembly.
[0118] The kit may additionally include a guide device 200 as shown
in FIG. 13a to aid the user in coiling the tubular members 20. The
device 200 has a base 202 for positioning on the ground or fixing
to a support, e.g. to a vehicle. An outwardly facing surface of the
device has a generally concave portion 204, preferably in the shape
of a horizontal cylindrical section, i.e. a cut taken across a
cylinder parallel to its axis, forming a cradle for helping roll up
a tubular member 20.
[0119] To use the device, the user first begins coiling the tubular
member 20 at one end e.g. at least a half turn, or complete turn
22. As shown by FIG. 13b, with the device 200 positioned, the user
places the coiled end 22 against the concave portion 204, and the
user applied a force F along the length of the member towards the
device 200, which causes the coil to slip and rotate in the concave
portion 204 whilst being retained in the concave portion 204, and
thereby causes the member 20 to continue to coil such that the
extended portion progressively gets added to the coil 22. Thus, the
member 20 can be quickly and simply coiled to a fully coiled state
once the initial coil is formed by simply applying downward force
F.
[0120] The surface of the concave portion 204 may be smooth and low
friction to aid slip between the coil 22 and concave portion. As
shown in FIG. 13A, the device 200 may have a main body 206 formed
from plastics, e.g. Nylon, for robustness and one or more low
friction plastics elements 208, e.g. Polyoxymethylene, fixed to the
body providing at least part of concave surface. In this example,
three curved guide strips 208 clip into position on the body 206
and are retained by threaded fasteners 210. These parts can be made
from injection moulded plastics, and so are simple and inexpensive
to manufacture and assemble, whilst being robust and providing low
rolling resistance.
[0121] The curvature of the cylindrical section 204 is preferably
approximately matches that of the coil 22. As the radius of
curvature of the member increases with each coil that is added, the
radius of curvature R of the cylinder may be selected to be in the
range defined by the radius of curvature of the middle coil of the
fully coiled member .+-.25%, or in some examples .+-.10%.
Preferably the angle subtended by the cylinder section is at least
90 degrees, and in some examples may be between 120 degrees and 180
degrees to more fully support the coiled member 22 as it rotates.
The sides of the cylinder are closed by walls 210 formed in the
body 206 of the device, with the length L of the cylinder equal to
or slightly larger than the width of the coiled member, to help
keep the coil in position during coiling. Thus, the concave portion
cradles the coil whilst permitting slip, allowing a downward force
to quickly and simply coil the entire member.
[0122] As discussed above, the system is capable of faster
deployment and recovery. Different combinations and numbers of
elements may be provided in the kits according to the application
and multipole kits can be used in combination to create even
further flexibility and variety of support masts. The use of
plastics materials for the connector elements 40, support element
80 and members 20 also has the advantage of lower thermal signature
and lower microwave signature compared with standard solutions
employing metals. Shaped rubber feet to allow grip on all terrain
and on vehicle external surfaces. The mast is also safer to use,
e.g. against static charge build up and/or lightning strike.
[0123] Embodiments of the present invention have been described
with particular reference to the example illustrated. However, it
will be appreciated that variations and modifications may be made
to the examples described within the scope of the present
invention.
* * * * *