Note: Descriptions are shown in the official language in which they were submitted.
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TOWER ASSEMBLY WITH BALLAST RECEIVING BASE
This application claims priority benefit to U.S. provisional application
Serial No. 62/328,864, filed April 28, 2016.
FIELD OF THE INVENTION
The present invention relates to a tower assembly, for example a
communications tower supporting an antenna thereon, in which a base of the
tower is
self-supported on a ground surface using ballast material supported on the
base, and
more particularly the present invention relates to a tower assembly having a
base
supporting a plurality of ballast receptacles thereon spaced radially outward
from a
central tower coupler that pivotally supports the bottom end of the tower
frame thereon
such that the tower frame can be erected using lifting equipment operatively
connected
between the tower base and the tower frame.
BACKGROUND
Towers structures are commonly used for supporting a variety equipment
thereon including communications antennas, lighting, signage, wind turbines,
solar
panels, and various transmission devices for example. To maintain the tower
supported
in a stable upright configuration, it is common to employ a foundation
penetrated into
the ground to resist overturning forces. The foundation typically includes one
or more
types of piles penetrated into the ground including concrete piles, screw
piles and the
like for example. Because of the various conditions of the ground into which a
foundation must be penetrating, the design requirements of the foundation may
vary
considerably between different installation sites which can involve costly and
time
consuming design requirements for each installation site. Even when a standard
foundation design is employed for use in different site conditions, the
installation of piles
including pouring of concrete can be costly and time consuming, particularly
in remote
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sites.
US patent applications 2014/0059957 by Stark and US 2015/0197957 by
Anderson, each disclose an example of a tower foundation structure which does
not
require penetration into the ground so as to be more suited to a variety of
different
installation conditions. In each instance a large platform is required to
support ballast
material thereon onto which the tower must be subsequently erected. The
location of
the ballast receiving platform directly adjacent to the base of the tower
requires a very
large amount of ballast to be supported thereon to resist overturning forces.
Furthermore, the raising of the tower onto the platform typically requires use
of costly
lifting equipment such as a crane or boom truck which is costly and may
trouble
accessing to the tower site in some remote locations.
SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided a tower
assembly comprising:
a support tower; and
a tower base for being supported on a ground surface, the tower base
comprising:
i) a tower coupler for supporting a bottom end of the support tower
thereon such that the support tower extends longitudinally upward from the
tower base;
ii) a plurality of frame members extending radially outward from the
tower coupler; and
iii) a ballast receptacle supported on each frame member at a
location spaced radially outward from the tower coupler for receiving ballast
material
therein.
The arrangement of radially oriented frame members extending between
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a central tower coupler and respective ballast receptacles allows for a more
efficient
use of ballast material to support the tower in a foundationless manner on a
ground
surface. The arrangement of the frame members also provides a frame assembly
which can be readily assembled from modular units for low cost and efficient
transport
and subsequent assembly of the tower on site.
When the support tower comprises three columns arranged in a triangular
configuration relative to one another, preferably the plurality of frame
members of the
tower base comprise three frame member extending radially outward from the
three
columns of the support tower respectively.
Preferably the tower base is a modular assembly in which each frame
member is connected between the tower coupler and the respective ballast
receptacle
using threaded fasteners such that each frame member is readily separable from
the
tower coupler and the respective ballast receptacle.
When the tower assembly further comprises a control box housing
telecommunications equipment therein connected to an antenna on the support
tower,
the control box is preferably supported at a distal end of one of the frame
members
opposite from the tower coupler.
Preferably the tower base is adapted to be supported on the ground
surface in a non-penetrating manner. Accordingly, when using a plurality of
guy-wires
connected between the support tower and the tower base, preferably these guy-
wires
are the only guy-wires connected to the support tower.
The tower coupler is preferably pivotally mounted on the frame assembly
such that the support tower is pivotal about a generally horizontal axis
between an
assembly position in which the support tower extends longitudinally outward
from the
tower base along the ground surface and a raised position in which the support
tower
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extends longitudinally upward from the tower base.
According to a second aspect of the present invention there is provided a
tower assembly comprising:
a support tower; and
a tower base comprising:
i) a plurality of frame members defining a frame assembly for being
supported on a ground surface;
ii) at least one ballast receptacle supported on the frame assembly
for receiving ballast material therein; and
iii) a tower coupler supported on the frame assembly for supporting
a bottom end of the support tower thereon, the tower coupler being pivotally
mounted
on the frame assembly such that the support tower is pivotal about a generally
horizontal pivot axis between an assembly position in which the support tower
extends
longitudinally outward from the tower base along the ground surface and a
raised
position in which the support tower extends longitudinally upward from the
tower base.
According to a further aspect of the present invention there is provided a
method of erecting a tower assembly comprising:
providing a support tower;
providing a tower base including i) a frame assembly, ii) at least one
ballast receptacle supported on the frame assembly, and iii) a tower coupler
supported
on the frame assembly;
supporting the frame assembly on a ground surface;
filling said at least one ballast receptacle with ballast material;
coupling a bottom end of the support tower to the tower coupler of the
tower base such that the support tower is pivotal about a generally horizontal
pivot axis
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between an assembly position in which the support tower extends longitudinally
outward from the tower base along the ground surface and a raised position in
which
the support tower extends longitudinally upward from the tower base;
pivotally raising the support tower from the assembly position to the raised
5 position; and
fixing the support tower to the tower base in the raised position.
The pivotal connection of the support tower to the tower base allows lifting
equipment to be connected directly between the support tower and the tower
base
without the need for auxiliary lifting equipment such as a crane or boom truck
being
required. The assembly and raising of the tower on site can thus be
accomplished
efficiently and at low cost.
When the plurality of frame members comprise three frame members
extending radially outwardly from the tower coupler to respective ballast
receptacles
spaced radially outward from the tower coupler at evenly spaced positions in a
circumferential direction about the tower coupler, preferably the tower
coupler supports
the support tower to extend from the tower coupler diametrically opposite from
one of
the three frame members in the assembly position.
The support tower may be raised using an additional lifting kit which is
temporarily attached to the tower assembly during lifting. The lifting kit
typically includes
a lifting strut supported relative to the support tower to extend radially
outward from a
longitudinal axis of the support tower, and a winch for lifting the support
tower from the
assembly position to the raised position. Preferably a winch cable of the
winch is
operatively connected between the lifting strut and the support tower.
Preferably the lifting strut is supported to extend radially outward from the
pivot axis of the tower coupler.
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Typically, a tension member, such as an additional cable, is supported
under tension between the lifting strut (at a location where the winch cable
is connected)
and the support tower at a central location along a length of the support
tower.
Once the support tower is erected into the raised position, the method
preferably includes coupling threaded fasteners between the support tower and
the
tower base to fix the support tower to the tower base in the raised position.
Preferably the support tower is assembled from a plurality of modular
tower sections in the assembly position of the support tower relative to the
tower base
prior to pivotally raising the support tower from the assembly position to the
raised
position.
One embodiment of the invention will now be described in conjunction
with the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a perspective view of the tower assembly;
Figure 2 is a top plan view of the tower assembly;
Figure 3 is a side elevational view along the line 3-3 of Figure 2;
Figure 4 is a rear elevational view along the line 4-4 of Figure 2;
Figure 5 is a perspective view of the tower base with the tower coupler
shown in the assembly position of the tower, but with the tower shown removed;
Figure 6 is a top plan view of the tower base in the assembly position;
Figure 7 is a side elevational view of the tower base in the assembly
position along the line 7-7 of Figure 6;
Figure 8 is a rear elevational view of the tower base in the assembly
position along the'line 8-8 of Figure 6;
Figure 9 is a perspective view of the tower base with the tower coupler
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shown in the raised position of the tower, but with the tower shown removed;
Figure 10 is a side elevational view of the tower base in the raised
position;
Figure 11 is a perspective view of a bottom side of the central frame
portion of the tower base in the raised position of the tower, but with the
tower shown
removed;
Figure 12 is a bottom plan view of the central frame portion of the tower
base in the raised position;
Figure 13 is a side elevational view of the central frame portion of the
tower base in the raised position;
Figure 14 is a perspective view of the tower in the assembly position with
the lifting kit supported thereon;
Figure 15 is a side elevational view of the tower in the assembly position
with the lifting kit supported thereon; and
- Figure 16 is a side elevational view of the tower with the lifting
kit
supported thereon in an intermediate position of the tower between the
assembly
position and the raised position.
In the drawings like characters of reference indicate corresponding parts
in the different figures.
DETAILED DESCRIPTION
Referring to the accompanying figures there is illustrated a tower
assembly generally indicated by reference numeral 10. The tower assembly is
particularly suited for supporting various types of equipment in an elevated
manner
above a ground surface. In the illustrated embodiment, the tower is adapted
for
supporting a communication antenna 12 thereon and further includes a control
box 14
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housing electronic communications equipment therein which is connected to the
antenna so as to enable communication among a plurality of towers to function
as a
wireless communications network.
The tower assembly 10 generally includes i) a tower base 16 for being
supported on the ground surface, and ii) a support tower 18 including a tower
frame
which is elongate in a longitudinal direction between a bottom end for being
supported
on the tower base 16 and an opposing top end supporting a communication
antenna
12 thereon.
The tower frame of the support tower comprises three columns 20
spanning the full height of the support tower in a triangular configuration
relative to one
another. The horizontal spacing between the columns is gradually reduced from
the
bottom end to the top end. A plurality of supporting struts (not shown) are
interconnected between the columns 20 to create a trust structure of the tower
frame.
Suitable brackets 22 protrude radially outward from the support frame at
vertically
spaced positions in proximity to the top end of the tower for supporting the
communication antennas 12 thereon.
Each column 20 includes a foot plate 24 mounted at the bottom end
thereof. The three foot plates 24 lie in a common plane perpendicular to the
longitudinal
axis of the support tower 18 and include fastener apertures therein for
securement to
the tower base as described in further detail below.
The tower base 16 generally includes i) a frame assembly having a central
frame portion 26 and three frame members 28 mounted two extend radially
outward
from the central frame portion at evenly spaced positions in the
circumferential
direction, ii) a tower coupler 30 supported on the central frame portion 26 to
couple the
support tower to the frame assembly of the tower base, and iii) three ballast
receptacles
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32 supported at the outer ends of the three frame members 28 respectively for
receiving
ballast material therein.
The central frame portion 26 includes an upper support plate 34 which is
generally triangular in shape so as to be similarly shaped and sized to the
triangular
pattern formed by the three foot plates 24 of the tower frame. Three mounting
plates
36 extend vertically downwardly from each of the three corners of the
triangular upper
support plate 34 such that each mounting plate 36 is tangentially oriented
relative to a
central vertical axis of the upper support plate. More particularly each of
the mounting
plates 36 is perpendicular to the upper supporting plate and perpendicular to
a radial
axis extending from the central axis of the upper support plate.
A side wall 38 depends vertically downward from each of the three side
edges of the upper support plate 34 such that each side wall 38 is connected
between
the respective adjacent pair of the mounting plates 36 at the corners of the
triangular
upper support plate 34. The side walls 38 extend downwardly by approximately
half of
the overall height of the mounting plates 36 at the corners of the upper
support plate.
Additional structural support is provided by three brace plates 40 mounted
below the upper support plate 34 in perpendicular relation to the upper
support plate.
Each brace plate 40 is joined to the other brace plates along an inner edge at
the central
axis of the upper support plate and extends radially outward towards an outer
edge
joined in perpendicular relation to the inner surface of a respective one of
the mounting
plates 36.
A lower plate 42 extends horizontally inward from a bottom end of each
mounting plate 36 to be joined to the bottom edge of the corresponding brace
plate 40
in proximity to the outer ends thereof for added structural support.
The three frame members 28 of the frame assembly of the tower base
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each comprise an I-beam extending along the full length thereof between an
inner end
44 and an outer end 46 of the beam. Each frame member thus comprises a top
flange,
a bottom flange;and a web connected between the top and bottom flanges in the
usual
manner of an I-beam. Each frame member further includes an end plate 48
connected
5
between the top and bottom flanges of the beam at each of the opposing inner
and
outer ends. The end plates 48 of each frame member are oriented transversely
to the
longitudinal direction of the respective frame member and are parallel to one
another.
The end plates 48 at the inner end of each frame member are sized and
shaped for mating abutment with a respective one of the mounting plates 36 of
the
10
central frame portion. Fastener apertures are provided in the inner end plate
in
alignment with corresponding fastener apertures in the respective mounting
plate 36 of
the central frame portion to permit threaded fasteners to secure the frame
members to
the central frame portion in a modular manner which permits subsequent
disassembly
as may be desired.
The end plates are oriented non-perpendicularly to the longitudinal
direction of the respective frame member such that bolting the inner end plate
flat
against the respective mounting plate of the central frame portion results in
the
longitudinal axis of the frame member extending radially outward at a downward
slope
from the inner end to the outer end of the frame member in the assembled
configuration.
When all three frame members are assembled, the three ballast receptacles
function
as footings of the overall tower base for engaging the ground and the central
frame
portion is supported to be spaced above the ground relative to the elevation
of the three
ballast receptacles.
Each ballast receptacle 32 includes a rectangular floor 50 defining the
bottom of the receptacles which is suitable for abutment flat against an upper
surface
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of the ground. An inner end wall 52 extends perpendicularly upward from an
inner edge
of the rectangular floor which includes a pattern a bolt apertures therein for
alignment
with corresponding bolt apertures within the corresponding end plate 48 at the
outer
end of a respective one of the frame members of the tower base. The bolt
apertures
permit threaded fasteners to secure the frame members to the ballast
receptacles
respectively in a modular manner which permits subsequent disassembly as may
be
desired.
Each ballast receptacle 32 further includes two side walls 54 extending
perpendicularly upward from opposing side edges of the rectangular floor 50 so
as to
be parallel and spaced apart from one another with the inner end wall being
connected
between inner edges of the two side walls respectively. A brace arm 56 is also
connected between the two side wails 54 at an opposing outer and of the
ballast
receptacle at a location spaced above the floor 50 at the top edges of the two
side walls.
The top side of the ballast receptacle remains open to readily permit ballast
material,
for example rocks or concrete blocks and like to be inserted into the
receptacle through
the open top end. Similarly, the outer end of the receptacle, opposite the
inner end wall
fastened to the respective frame member, also remains open for ease of loading
ballast
material into the receptacle.
The tower coupler 30 comprises a pivot plate 58 which is generally
triangular in shape and sized similarly to the upper support plate 34 of the
central frame
portion such that the pivot plate is suitably arranged for alignment with and
flat
engagement upon an upper surface of the upper supporting plate in a finished
assembled configuration of the tower. The pivot plate 58 is coupled along one
of the
three edges of the triangular shape of the plate to a corresponding edge of
the triangular
upper support plate 34 by a hinge pin 60 which is horizontally oriented and
parallel to
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the corresponding side edges of the plates.
The pivot plate 58 further includes an upright flange 62 protruding
perpendicularly upward from the plate when the plate is horizontally oriented
along the
edge of the pivot plate corresponding to the hinge coupling. The other two
edges of the
triangular pivot plate 58 include a depending flange 64 formed thereon which
depends
downwardly when the pivot plate 58 is horizontally oriented against the upper
surface
of the support plate 34. The pivot plate 58 of the tower coupler is slightly
larger in
dimension than the triangular support plate 34 to allow the depending flanges
to extend
downwardly alongside the outer sides of the side walls 38 of the central frame
portion
of the base.
The hinge pin 60 is coupled to the pivot plate 58 by three hinge plates
which are axially spaced apart at fixed positions along the outer side of the
upright
flange 62 and three corresponding hinge plates which are axially spaced apart
along
the corresponding edge of the upper support plate 34 in fixed relation
thereto. The hinge
pin 60 which defines the pivot axis of the pivot plate relative to the upper
support plate
extends through corresponding pivot apertures in each of the hinge plates.
Each foot plate 24 at the bottom of the tower frame includes three fastener
apertures therein which are suitably aligned with corresponding fastener
apertures in
the pivot plate 58. Suitable threaded fasteners can thus be used to bolt each
foot plate
to the pivot plate 58 of the tower coupler such that the tower is pivotal
together with the
pivot plate 58 about the pivot axis of the hinge pin 60 between an assembly
position in
which the pivot plate extends upward from the pivot axis so that the tower
coupled
thereto extends generally horizontally along the ground surface, and a raised
position
in which the pivot plate 58 is generally horizontally oriented against the
upper surface
of the upper support plate 34 so that the tower extends longitudinally upward
in
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alignment with the central vertical axis of the central frame portion of the
tower base.
The upper support plate 34 includes one fastener aperture 66 in alignment
with the outermost one of the three fastener apertures for each foot plate 24
of the tower
frame. A common threaded fastener is thus adapted to be received through each
fastener aperture 66 for collectively fasting together the upper support plate
34, the
pivot plate 58, and a respective one of the foot plates 24.
The upper support plate 34 also includes two access holes 68 associated
with each foot plate 24 such that the two access holes are aligned with the
two other
fastener apertures of the respective foot plate 24 which do not align with a
corresponding fastener aperture 66 in the upper plate. The access holes 68 are
larger
in dimension than the heads of the fasteners used at the other fastener
locations of the
foot plate. In this manner suitable threaded fasteners can be used to secure
the foot
plates 24 to the pivot plate 58 while the pivot plate remains in the assembly
position of
the tower. As the tower is subsequently raised, the threaded fasteners which
are
already used to secure the foot plates 24 to the pivot plate 58 are not in
interference
with the upper plate by being axially aligned with and received through the
corresponding access holes 68.
The assembly of the tower described herein typically involves transporting
the central frame portion 26 of the tower base, the frame members 28 of the
tower base,
the ballast receptacles 32, and various modular sections of the support tower
frame as
separate modular components to the site of the tower. The tower base is
initially
assembled using threaded fasteners to connect the frame members 28 between the
central frame portion 26 and respective ones of the ballast receptacles 32.
The pivot
plate of the tower coupler 30 on the tower base can then be pivoted into an
upright
orientation corresponding to the assembly position of the tower so that the
modular
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tower sections can be assembled to one another to form the tower frame
together with
the bottom end of the tower frame being fastened to the pivot plate of the
tower coupler.
Prior to pivotally raising the support tower, ballast material is placed in
each of the ballast receptacles. Suitable lifting equipment can then be used
to raise the
tower into the raised position. Once in the raised position, the third
threaded fastener
associated with each foot plate 24 is used to fasten the foot plates through
the pivot
plate 58 to the corresponding aperture 66 of the underlying upper support
plate 34 of
the central frame portion of the tower base to fix the tower frame relative to
the tower
base in the raised position.
In the preferred embodiment, the lifting equipment used to raise the tower
comprises a lifting kit which is temporarily attached to the tower assembly
only during
lifting of the tower from the assembly position to the raised position. The
lifting kit
generally includes a lifting strut 70 comprised of two arms 72 which are
pivotally
connected at respective inner ends of the arms to axially opposed ends of the
hinge pin
60 such that the lifting strut is pivotal about the hinge pin together with
the tower frame.
Opposing outer ends of the two arms 72 are coupled to one another. A tension
member
74, for example a cable, is connected under tension between the outer ends of
the two
arms 72 of the lifting strut 70 and the tower frame at a central location
along the length
of the tower frame between the top and bottom ends thereof.
A winch 76 is operatively connected between the tower base and the
support tower through the lifting strut 70. More particularly the winch 76
includes a
winch cable 78 having a first end secured to a drum onto which the cable is
arranged
to be wound and which is supported on the frame member 28 of the tower base
that is
diametrically opposite from the tower frame in the assembly position relative
to a central
axis of the central frame portion. An opposing second end of the winch cable
is secured
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to the outer end of the lifting strut. The lifting strut is thus supported to
extend generally
radially outward from the longitudinal axis of the tower frame, and more
particularly to
extend radially outward from the pivot axis of the hinge pin.
The winch is secured to the corresponding frame member 28 at the
5 location of the connection to the ballast receptacle towards the outer
end of the frame
member. A radial length of the strut is near to the length of the frame member
such that
the outer end of the strut substantially aligns with the outer end of the
frame member
locating the winch thereon. Winding the cable 78 onto the drum of the winch
causes
the outer end of the lifting strut to be drawn towards the outer end of the
corresponding
10 frame member supporting the winch thereon while the tower frame pivots
together with
the strut by the tension through the tension member 74 until the tower is
erected. Once
erected, the final fasteners are inserted through the corresponding fastener
apertures
66 in the upper support plate 34 to fix the tower frame in the raised position
as described
above. The lifting strut and winch can be removed once the tower is fixed in
the raised
15 position.
Since various modifications can be made in my invention as herein above
described, and many apparently widely different embodiments of same made, it
is
intended that all matter contained in the accompanying specification shall be
interpreted
as illustrative only and not in a limiting sense.
