Note: Descriptions are shown in the official language in which they were submitted.
CA 02821292 2013-07-18
LIGHT TOWER
TECHNICAL FIELD
[0001] Light towers.
BACKGROUND
[0002] Safety requirements at oil industry and other work sites require
good lighting at
night. The lighting elements need to be bright and preferably high so as not
to cast too many
shadows. Shadows preferably are avoided as much as possible. A solution to
having full lighting
without shadows is to have many lights, but this adds expense. In addition,
the requirements are
complicated by the work sites being remote, so that the equipment needs to be
easily portable. In
addition, it is desirable to have a smaller footprint of the equipment at the
work site.
SUMMARY
[0003] There is therefore disclosed a light tower that provides high,
bright light from a
portable low energy light tower.
[0004] A low energy light tower is disclosed. In an embodiment, a light tower
is provided,
comprising a base having ground engaging elements, a telescoping mast secured
to the base, the
telescoping mast having a top end, lighting elements at the top end of the
telescoping mast; and a
linear actuator mounted on the telescoping mast for extending and retracting
the telescoping
mast, the linear actuator being electrically operated. In an embodiment, the
lighting elements are
LEDs. In an embodiment, the telescoping mast is rotatable about a pivot to
assist movement
between a transport position and an operating position.
[0005] In various embodiments, there may be included any one or more of the
following
features: the base has parallel longer sides; the base has a tower cradle,
which may be height
adjustable, and the telescoping mast lies on the telescoping tower cradle in
the transport position;
the telescoping mast, in the transport position, lies at an angle to
horizontal; the base has a shape
for arranging the light tower in a rectangular grid; the linear actuator is
connected to extend and
retract the telescoping mast through cables lying along the telescoping mast;
the telescoping mast
comprises at least four sections; the telescoping mast comprises plural
sections, each section
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having a length of three meters or more; the top end comprises a cross-bar,
the cross-bar
supporting a pair of panels on either side of the cross-bar; the ground
engaging elements
comprise pads; the base comprises fork lift receivers. In an embodiment there
is a group of at
least three light towers and an electrical generator, each light tower being
constructed according
to any of the disclosed embodiments, the light towers being electrically
connected in a chain to
the electrical generator.
[0006] These and other aspects of the device are set out in the claims,
which are
incorporated here by reference.
BRIEF DESCRIPTION OF THE FIGURES
[0007] Embodiments will now be described with reference to the figures, in
which like
reference characters denote like elements, by way of example, and in which:
[0008] Fig. 1 is a perspective view of a light tower with a telescoping
mast.
[0009] Fig. 2 is a side view of the light tower of Fig. 1 showing a linear
actuator and
cable system.
[0010] Fig. 3 is a perspective view of the light tower of Fig. 1 showing
the mast in a
transport position.
[0011] Fig. 3A is a diagram showing orientation of the mast in a vertical
plane for
transport.
[0012] Fig. 4 is a perspective view of a collection of lights towers of
Fig. 1 prepared for
transport.
[0013] Fig. 5 is an illustration of an employment of light towers of Fig.
1 connected to a
power source.
DETAILED DESCRIPTION
[0014] Immaterial modifications may be made to the embodiments described
here
without departing from what is covered by the claims.
[0015] Referring to Fig. 1, a light tower 10 comprises a base 12 having
ground engaging
elements 11, 14 and 16. A telescoping mast 18 is supported on the base 12. The
mast 18 may
have any suitable cross-sectional shape such as round, square, rectangular or
other polygonal
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shape. Ground engaging elements 14 comprise pads on the end of extendable arms
such as swing
arms 15. Other extendable arms could be used for example sliding arms or arms
that are
detachable. The ground engaging elements comprise beams 11 at the respective
ends of the base
12. The base may also comprise fork lift receivers 16 for lifting and moving
the light tower 10.
The fork lift receivers 16 may also function as ground engaging elements to
support the base 12.
The swing arms 15 are located at one end of the base 12 and are rotationally
attached to the base
12 through posts 15A that extend upward from corners of the base 12. Frames
15B are pivotally
mounted on the posts 15A and at the ends of the frames 15B there is a hollow
post 15C that
receives an extendable bar 15D. The pads 14 are secured to the bottom of the
extendable bars
150; The posts 15A and therefore the pads 14 are preferably height adjustable,
for example
using a rack and pinion system (not shown) operated by a crank 15E. Opposite
corners of the
base 12 from the posts 15A have posts 13 that extend upward from base 12. The
tops of the
posts 13 and 15A have eyelets for receiving hooks when the light tower 10 is
being hoisted.
[0016] The base 12 may include ballast for the light tower 10. Ballast may
be provided
in any of various ways for weighting the base 12 to resist movement of the
mast 18 in winds or
when the mast l 8 is being telescopically extended. One method of providing
ballast for the light
tower 10 is to provide weight in the base 12 for example by making the base 12
out of a steel
frame with channels or pockets filled with cement. Another way is to make the
light tower 10
and particularly the base 12 out of sufficiently heavy material to resist
tipping of the light tower
10. For example, for a 40 ft light tower 10, the light tower 10 may have a
weight of about 4000
lbs, most of which is in or near the base 12. The base 12 may itself weight 11
lbs or more.
[0001] A telescoping mast 18 with lower part 17 is secured to the base 12
on cylindrical
base 19 and has a pivot 20 at a lower end of the telescoping mast 18. The
telescoping mast 18
may be secured to the base 12 in line with the posts 15A. The telescoping mast
18 may be
arranged to rotate about a vertical axis extending through the base 19.
Handles (not shown) on
the lower part 17 of the tower 18 may be used to rotate the mast about the
base 19 by hand,
although the rotation may also or instead be powered by an electric motor (not
shown).
[0002] The telescoping mast 18 may also be arranged to rotate about a
horizontal axis
defined by the pivot 20, using actuators 21, for example electrical linear
actuators. The
telescoping mast 18 terminates in a top end 22 formed of a cross-bar 24 on
which are mounted
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lighting elements 26, for example a pair of LED panels, on either side of the
cross-bar. The
lighting elements 26 in an embodiment may be LEDs with 19,000 or more lumens
per panel.
The telescoping mast 18 is rotatable about the pivot 20 between a transport
position shown in
Figs. 3 and 4 and an operating position shown in Fig. 1. Boxes 27 on the base
12 may be used to
house electrical equipment including LED panels (for example during
transport), backup dry cell
batteries, and electrical cables, for example a cable roll with 60 meter
cable. The cross-bar 24
may be arranged to rotate or the LED panels 26 may be arranged to rotate on
the cross-bar 24 to
allow the panels 26 to point straight down. Another set of LED panels could be
oriented to point
180 degrees from the panels 26 shown.
[0003] Referring to Fig. 2, a linear actuator 28 is mounted on the
telescoping mast 18 for
extending and retracting the telescoping mast 18. In conjunction with the
actuators 21, the
telescoping mast 18 may therefore be first rotated and then extended to move
the telescoping
mast 18 between the transport position and operating position, and then
retracted and rotated
back to the transport position when required. The linear actuator 28 is
electrically operated and
powered by motor 29 through a gear powered nut and screw arrangement (not
shown), and is
connected to extend and retract the telescoping mast through cables 30 that
lie along the
telescoping mast 18, although in some embodiments the actuator 28 may be
hydraulically or
pneumatically operated. Each cable extends around a corresponding pulley 31
attached to the
telescoping mast. A first cable also extends around an actuator pulley 70 on
the linear actuator
28. The light tower preferably has one less cable than telescoping mast
sections. The linear
actuator may be any of many suitable commercially available electrical
actuators. In some
embodiments, if the telescoping mast 18 compacts sufficiently by telescoping,
the rotational
movement of the telescoping mast 18 may be omitted and only telescoping be
used. In such an
instance, a larger number of telescoping sections may be used, and the bottom
section will be
considerably wider than the top section.
[0004] An example of a telescoping mast 18 shown in Fig. 2 with four
sections the cables
may be arranged as follows: a first end of the first cable 44 extends over a
first pulley 50
mounted close to the top end of a first section 56 of the telescoping mast 18,
extends around the
actuator pulley 70 attached to the linear actuator 28 and is attached to the
outer surface of the
first section 56 below the first pulley 50. A second end of the first cable 44
extends between the
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first section 56 and a second section 58 that extends within the first section
56 and is anchored 64
near the bottom end of the second section 58. A first end of a second cable 46
extends over a
second pulley 52 mounted close to the top end of the second section 58 and is
attached to the
outer surface of the first section 56 near the top of the first section 56. A
second end of the
second cable 46 extends between the second section 58 and a third section 60
that extends within
the second section 58 and is anchored 66 near the bottom end of the third
section 60. A first end
of a third cable 48 extends over a third pulley 54 mounted close to the top
end of the third section
60 and is attached to the outer surface of the second section 58 near the top
end of the second
section 58. A second end of the third cable 48 extends between the third
section 60 and a fourth
section 62 that extends within the third section 60 and is anchored 68 near
the bottom end of the
fourth section 62. This cable and pulley system preferably allows the linear
actuator to extend
and retract all of the telescoping mast sections simultaneously. Additional
cables and pulleys
may be added and used to extend and retract additional telescoping sections.
The sections of the
mast 18 may for example be each 3 meters long, for a total of 12 meters height
above the pivot
20, which itself may for example be 1-2 meters above the base 12. A power cord
for the LED
lights may be coiled in a cylinder 69 mounted on the base 12 and uncoiled when
the LED lights
are raised by the actuator 28.
[0005] The
light tower 10 is preferably designed to fit together with other light towers
10
of the same shape to form a rectangular grid for transport, as shown in Figs.
3, 3A and 4. In an
embodiment, the base 12 has parallel longer sides 32 and shorter sides 34. In
the transport
position as shown in Figs. 3 and 3A, the telescoping mast 18 lies at an angle
A above horizontal
supported by telescoping tower cradle 38. A pin 39 on the telescoping tower
cradle 38 may be
inserted in corresponding holes in the outer and inner members of the cradle
38 to adjust the
angle A. The angle A is chosen so that telescoping masts 18 of adjacent light
towers 10 do not
interfere with each other even when loaded for transport on a vehicle 36 with
the telescoping
masts 18 in the retracted position, with the top ends 22 extending beyond the
foot print of the
bases 12. The mast 18 may also be lowered, for example to or below horizontal
on the cradle 38,
for ease of working on the LEDs and other components on the mast 18. For
example, the lighting
elements are preferably detached from the top of the mast 18 for transport. As
shown in Fig. 4,
CA 02821292 2013-07-18
the bases 12 are suitably shaped to fit together in a rectangular grid, for
example by being
rectangular or other space filling polygonal shape.
[0006] The telescoping mast 18 preferably comprises at least four sections
of length three
meters or more. As shown in Fig. 5, with a group of light towers 10 deployed
at a work site with
the telescoping masts 18 in operating upright position, the light towers 10
may be organized in
an electrically connected chain of three (or more) light towers 10 and
connected to a single
electrical generator 40. Additional light towers 10 may be added as the
capacity of the electrical
generator 40 permits. The light tower may be powered from an onsite AC
generator with battery
backup. The AC generator may be disconnected and the light tower run on
battery backup when
maintenance is being done on the AC generator. In an embodiment, the battery
backup may
supply 3 hours of battery reserve at 40 amps and 24 volts. A photocell may be
used in the
electrical circuit to shut down power during daylight hours when lights are
not required.
[0007] In the claims, the word "comprising" is used in its inclusive sense
and does not
exclude other elements being present. The indefinite articles "a" and "an"
before a claim feature
do not exclude more than one of the feature being present. Each one of the
individual features
described here may be used in one or more embodiments and is not, by virtue
only of being
described here, to be construed as essential to all embodiments as defined by
the claims.
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