U.S. patent application number 15/277289 was filed with the patent office on 2017-01-19 for flexible moment connection device for mast arm signal mounting.
The applicant listed for this patent is Robert E. Townsend, JR.. Invention is credited to Robert E. Townsend, JR..
Application Number | 20170016189 15/277289 |
Document ID | / |
Family ID | 54769267 |
Filed Date | 2017-01-19 |
United States Patent
Application |
20170016189 |
Kind Code |
A1 |
Townsend, JR.; Robert E. |
January 19, 2017 |
Flexible Moment Connection Device for Mast Arm Signal Mounting
Abstract
An attachment assembly and a method for mounting a traffic
control device to a mast arm are provided. The attachment assembly
includes an attachment device. The attachment device includes a
first portion operably connect to the mast arm so that a first
surface of the first portion is oriented toward the mast arm, a
second portion extending substantially parallel to the first
portion along at least a portion of a first length, a second
surface of the second portion is oriented toward the traffic
control device, and a third portion having a third length and
extending between the first portion and the second portion so that
a gap is formed between a second face of the first portion and a
first face of the second portion that allows the attachment device
to flex when the traffic control device is mounted to the mast
arm.
Inventors: |
Townsend, JR.; Robert E.;
(Lake Wales, FL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Townsend, JR.; Robert E. |
Lake Wales |
FL |
US |
|
|
Family ID: |
54769267 |
Appl. No.: |
15/277289 |
Filed: |
September 27, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14514135 |
Oct 14, 2014 |
9458974 |
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15277289 |
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14496668 |
Sep 25, 2014 |
8985535 |
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14514135 |
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62038399 |
Aug 18, 2014 |
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62009258 |
Jun 8, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G08G 1/095 20130101;
Y10T 29/49828 20150115; F21V 21/116 20130101; G08G 1/01 20130101;
F16M 13/022 20130101; E01F 9/658 20160201; E04H 12/18 20130101;
F21S 8/085 20130101; F21W 2111/02 20130101 |
International
Class: |
E01F 9/658 20060101
E01F009/658; F16M 13/02 20060101 F16M013/02; F21V 21/116 20060101
F21V021/116 |
Claims
1. A method of mounting a traffic control device to a mast arm, the
method comprising: connecting an attachment assembly to the mast
arm, the attachment assembly comprising a first attachment device,
the first attachment device comprising: a first portion having a
first length, the first portion comprising a plurality of
apertures, the first portion having a first surface that is
oriented toward the mast arm; a second portion having a second
length, the second portion comprising a plurality of apertures, the
second portion extending substantially parallel to the first
portion along at least a portion of the first length, the second
portion having a second surface that is oriented toward the traffic
control device; and a third portion having a third length and
extending between the first portion and the second portion so that
a gap is formed between a second face of the first portion and a
first face of the second portion that allows the attachment device
to flex when the traffic control device is mounted to the mast arm;
and connecting the traffic signal to the first attachment
device.
2. The method according to claim 1, comprising securing the
attachment assembly to the mast arm using a cable.
3. The method according to claim 2, comprising securing a second
attachment device of the attachment assembly to the mast arm and
connecting the first attachment device to the second attachment
device with at least a portion of the cable positioned between the
first and second attachment devices.
4. The method according to claim 3, comprising positioning the
first attachment device relative to the second attachment device
such that a displacement gap is formed between at least a portion
of the first attachment device and the second attachment
device.
5. The method according to claim 4, comprising connecting the first
attachment device to the second attachment device with a plurality
of connectors so that the displacement gap is formed.
6. The method according to claim 3, comprising positioning the
second attachment device so that a first surface of the second
attachment device is facing the mast arm and a portion of the first
surface is spaced apart from the mast arm.
7. The method according to claim 6, comprising positioning an
engagement flange of the second attachment device against the mast
arm so that the first surface of the second attachment device is
spaced apart from the mast arm.
8. The method according to claim 4, comprising positioning the
second attachment device so that a first surface of the second
attachment device is facing the mast arm and a portion of the first
surface of the second attachment device is spaced apart from the
mast arm.
9. The method according to claim 3, comprising inserting the cable
into an adjustment slot of the second attachment device.
10. The method according to claim 9, comprising inserting the cable
through a cable clamp connected to the second attachment
device.
11. The method according to claim 1, wherein the first attachment
device comprises a fourth portion having a fourth length that
extends between the first portion and the second portion.
12. The method according to claim 3, further comprising connecting
a traffic control device to the first attachment device.
13. The method according to claim 12, wherein the first attachment
device dynamically responds to both vertical and horizontal
displacement of the traffic control device.
14. The method according to claim 3, further comprising connecting
a single unit signal housing to the first attachment device.
15. The method according to claim 3, comprising using a tool
comprising a handle and a lever plate to tighten the cable.
16. The method according to claim 15, comprising inserting the
lever plate between a gap between the cable and a second surface of
the second attachment device and tightening the cable.
17. The method according to claim 3, comprising positioning the
first attachment device and the second attachment device relative
to each other so that both the first attachment device and the
second attachment device are flexible.
Description
RELATED APPLICATIONS
[0001] This application is a divisional application of U.S.
application Ser. No. 14/514,135, filed Oct. 14, 2014, which is a
continuation-in-part of U.S. application Ser. No. 14/496,668, filed
Sep. 25, 2014, now U.S. Pat. No. 8,985,535, and claims the benefit
of the filing date under 35 U.S.C. .sctn.119(e) of Provisional U.S.
Application Ser. No. 62/009,258, filed Jun. 8, 2014, and
Provisional U.S. Application Ser. No. 62/038,399, filed Aug. 18,
2014, which are hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
traffic control devices and in particular to mast arm support
structures and traffic control devices each susceptible to dynamic
wind loads that may damage the connection between the horizontal
and vertical mast arm support structure and between the traffic
control device and the mast arm and to flexible mounting assemblies
for mounting traffic control devices to mast arms.
BACKGROUND
[0003] Roadway intersections, when warranted, require signalization
to maintain safety and efficient movement of vehicular traffic.
Traffic control devices (signals, signs, cameras, etc.) are
generally supported on roadside posts, suspended from span wires or
rigidly mounted on steel mast arms cantilevered over the roadway
from a vertical pole that is designed as a rigid structure.
[0004] Steel mast arm traffic signal support structures are
typically rigidly designed to resist high wind loads imparted to
the poles and mast arms. The current design concerns (moments) are
only directed now to the base of the pole and to the connection of
the mast arm to the pole. In addition, the current designs use a
rigid connection including drilled and tapped cast aluminum
connections to connect the traffic signal to the mast arm. Common
prior art cable securements rely on single in-plane surface plate
to cable pressures and non-consistent, unpredictable use of acute
cable angles.
[0005] What is needed in the art is an attachment device and an
attachment assembly for connecting a traffic control device to a
mast arm that provides a flexible connection for connecting the
traffic control device to the mast arm. In some aspects, using
cables to secure the traffic control device to the mast arm, an
assembly including multiplane surface-cable pressures and that
provides for consistent use of acute cable angles is needed.
BRIEF SUMMARY
[0006] It is an object of the present invention to provide a device
and a method having features that resolve or improve on rigid
connection devices connecting traffic control devices to mast arms.
In some embodiments, the devices and methods provided herein
minimize the effects of structural fatigue vibrations.
[0007] In one aspect, an attachment assembly for mounting a traffic
control device to a mast arm is provided. The attachment assembly
includes an attachment device. The attachment device includes a
first portion having a first length and the first portion includes
a plurality of apertures. The first portion is adapted to operably
connect to the mast arm so that a first surface of the first
portion is oriented toward the mast arm. The attachment device
includes a second portion having a second length and the second
portion includes a plurality of apertures. The second portion
extends substantially parallel to the first portion along at least
a portion of the first length. The second portion is adapted to
operably connect to the traffic control device so that a second
surface of the second portion is oriented toward the traffic
control device. The attachment device includes a third portion
having a third length and extending between the first portion and
the second portion so that a gap is formed between a second face of
the first portion and a first face of the second portion that
allows the attachment device to flex when the traffic control
device is mounted to the mast arm.
[0008] In another aspect, an attachment assembly for mounting a
traffic control device to a mast arm is provided. The attachment
assembly includes a first attachment device and a second attachment
device. The first attachment device includes a first portion having
a first length and the first portion includes a plurality of
apertures. The first portion is adapted to operably connect to the
mast arm so that a first surface of the first portion is oriented
toward the mast arm. The first attachment device includes a second
portion having a second length and the second portion includes a
plurality of apertures. The second portion extends substantially
parallel to the first portion along at least a portion of the first
length. The second portion is adapted to operably connect to the
traffic control device so that a second surface of the second
portion is oriented toward the traffic control device. The first
attachment device includes a third portion having a third length
and extending between the first portion and the second portion so
that a gap is formed between a second face of the first portion and
a first face of the second portion that allows the attachment
device to flex when the traffic control device is mounted to the
mast arm. The second attachment device has a first surface and a
second surface opposite the first surface and the second attachment
device is operably connectable to the mast arm.
[0009] In another aspect, a method of mounting a traffic control
device to a mast arm is provided. The method includes connecting an
attachment assembly including a first attachment device to the mast
arm. The first attachment device includes a first portion having a
first length and the first portion includes a plurality of
apertures. The first portion is adapted to operably connect to the
mast arm so that a first surface of the first portion is oriented
toward the mast arm. The first attachment device includes a second
portion having a second length and the second portion includes a
plurality of apertures. The second portion extends substantially
parallel to the first portion along at least a portion of the first
length. The second portion is adapted to operably connect to the
traffic control device so that a second surface of the second
portion is oriented toward the traffic control device. The first
attachment device includes a third portion having a third length
and extending between the first portion and the second portion so
that a gap is formed between a second face of the first portion and
a first face of the second portion that allows the attachment
device to flex when the traffic control device is mounted to the
mast arm. The second attachment device has a first surface and a
second surface opposite the first surface and the second attachment
device is operably connectable to the mast arm. The method further
includes connecting the traffic signal to the first attachment
device.
[0010] Advantages of the present disclosure will become more
apparent to those skilled in the art from the following description
of embodiments that have been shown and described by way of
illustration. The invention is capable of other and different
embodiments, and its details are capable of modification in various
respects. Accordingly, the drawings and description are to be
regarded as illustrative in nature and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a right hand view illustration an embodiment of a
mast arm saddle and swivel plate of an attachment assembly in
accordance with the present invention;
[0012] FIG. 2 is a left hand view illustration of an embodiment of
a mast arm saddle and swivel plate of an attachment assembly and a
sectional portion of a standard traffic signal support tube;
[0013] FIG. 3A is an isometric view taken from one end of the mast
arm saddle shown in FIG. 1;
[0014] FIG. 3B is also an isometric view of the opposite end of the
mast arm saddle shown in FIG. 3A;
[0015] FIG. 4 is a side view of a mast arm saddle and a mast
arm.
[0016] FIG. 5 is a cross sectional view taken along 5 of FIG.
1;
[0017] FIG. 6 is a plan view of an embodiment of a swivel
plate;
[0018] FIG. 7 is an isometric view of an embodiment of a mast arm
saddle;
[0019] FIG. 8 is a cross section taken along line A-A of FIG.
7;
[0020] FIG. 9 is an embodiment of a tool that may be used to apply
tension to the attachment assembly;
[0021] FIG. 10 illustrates an embodiment of the tool applying
tension to the attachment assembly;
[0022] FIGS. 11A and 11B illustrate a side view of an embodiment of
a mast arm saddle and a swivel plate with a single unit traffic
signal mounted thereto;
[0023] FIG. 12 is a portional isometric view of an embodiment of an
attachment assembly for horizontal installations;
[0024] FIG. 13 is an isometric view of an embodiment of a saddle
plate providing both horizontal and vertical movements;
[0025] FIG. 14 is an isometric view of an embodiment of the saddle
plate shown in FIG. 9 connected to a mast arm; and
[0026] FIG. 15 is an isometric view of an embodiment of a saddle
plate in accordance with the present invention.
DETAILED DESCRIPTION
[0027] The invention is described with reference to the drawings in
which like elements are referred to by like numerals. The
relationship and functioning of the various elements of this
invention are better understood by the following detailed
description. However, the embodiments of this invention are not
limited to the embodiments illustrated in the drawings. It should
be understood that the drawings are not to scale, and in certain
instances details have been omitted which are not necessary for an
understanding of the present invention, such as conventional
fabrication and assembly.
[0028] In some aspects, the present invention is directed to the
improvement of common mast arm rigid traffic control device
mounting assemblies that provide a rigid connection between a
traffic control device and a mast arm. The present invention
addresses the known structural deficiencies of the prior art by
providing a flexible mast arm saddle and/or flexible swivel type
connection device that is approximately 3-5 times stronger, and not
susceptible to cracking due to either wind loading and/or installer
failure to torque properly. In addition, the present invention
provides a much stronger shear-type connection using through
bolting to connect the traffic control device to the mast arm. In
some embodiments, the attachment assembly of the present invention
can perform as a means to dampen wind induced forces.
[0029] Rigidity is the property of a structure that it does not
bend or flex under an applied force. The opposite of rigidity is
flexibility. In structural rigidity theory, structures are formed
by collections of objects that are themselves rigid bodies. A
structure is rigid if it cannot flex; that is, if there is no
continuous motion of the structure that preserves the shape of its
rigid components and the pattern of their connections then the
structure becomes susceptible to forces placed upon the structure
such as wind induced accelerations.
[0030] It is a basic engineering design principle that, if
possible, a structure must have features that allow for
flexibility, while still maintaining its structural loading
requirements such as gravitational and wind induced accelerations.
The present invention utilizes the "Flexible Moment Connection",
semi-rigid approach. The basic principles of the FMC approach are
to treat the beams (saddle & swivel) as simply connected under
gravity loads but as moment connected under lateral (wind) loads.
The FMC can be basically described as three types of connections:
One that exhibits a small amount of rotation with a large amount of
moment is noted as a rigid connection (prior art). A second
connection that exhibits a large amount of rotation with a small
amount of moment is noted as simple. The third connection is noted
as a semi-rigid connection and provides some moment restraint while
permitting some rotation (present invention). Semi-rigid
connections can fall anywhere between simple and rigid. In general,
connections capable of resisting at least 90 percent of the beam
fixed-end moment are referred to as rigid. Those that offer enough
ductility to accommodate beam end rotation while resisting no more
than 20 percent of the fixed-end moment are referred to as simple.
Any connection that is capable of resisting a moment between these
limits while permitting some rotation must be treated as semi-rigid
or flexible.
[0031] In some embodiments, the attachment assembly of the present
invention can respond to both vertical and horizontal oscillations
(vibrations) by absorption and/or dampening wind induced structural
fatigue vibrations.
[0032] When a lateral load (wind) is applied to a mast arm
structure, the windward connection of both the mast arm saddle, the
swivel plate and sometimes flexible flange (used to replace common
tubes) will load in a flexural response in the present invention,
therefore resulting in a significant increased wind resistance over
the prior art's common rigid saddle, swivel plates, and traffic
signal support tubes that have very limited, if any, resiliency. It
is better for any structure to have less stress due to elasticity
than having to absorb any amount of wind force or wind induced
kinetic energy.
[0033] An additional benefit of the present invention is that when
the swivel plate, and optionally the flexible signal bracket,
because of their size relative to the mast arm, unload faster in a
direction that is opposite of the wind induced displacement that
may be horizontal, vertical or both horizontal and vertical
creating a dampening effect helping to reduce the moment stresses
that occur at the structure's connection of the horizontal mast to
the vertical pole; based upon Newton's second law of motion:
Firstly, this law states that if you do place a force on an object,
it will accelerate (change its velocity), and it will change its
velocity in the direction of the force. So, a force aimed in a
positive direction will create a positive change in velocity (a
positive acceleration). And a force aimed in a negative direction
will create a negative change in velocity (a negative
acceleration).
[0034] Cantilevered mast arms are susceptible to four types of wind
loading that may induce vibrations that can lead to fatigue
failures such as vortex shedding, galloping, natural, wind gust and
truck-induced wind gust failures.
[0035] In another aspect, the present invention avoids galvanic
corrosion risk, especially in wet, salty coastal areas with the
aluminum and stainless steel in contact with one another, typical
to all prior art aluminum castings that are secured with stainless
steel fasteners and more importantly stainless steel cables used to
secure the entire traffic control device to the mast arm support.
In order for galvanic corrosion to occur, three elements are
required: 1) Two metals with different corrosion potentials; 2)
Direct metal-to-metal electrical contact; and 3) A conductive
electrolyte solution (e.g. moisture) must connect the two metals on
a regular basis. The electrolyte solution creates a "conductive
path" such as when there is regular immersion, condensation, rain,
fog exposure or other sources of moisture that dampen and connect
the two metals.
[0036] In some embodiments, the attachment assembly of the present
invention provides a wind resilient and hurricane resistant traffic
signal mounting device by providing a much stronger connection to a
cantilevered mast arm.
[0037] In some embodiments, the attachment assembly of the present
invention is directed to improving the survival of mast arm
signalization during high wind events by resisting and minimizing
the structural failures (cracked castings) known to occur in
current--typical rigid cast aluminum traffic signal mounting
bracket assemblies.
[0038] Ideally, the frequencies and the amplitudes of any dampening
device and the structure should nearly match so that every time the
wind pushes the mast arm, the dampener(s) create(s) an equal and
opposite push on the structure, keeping the displacement of the
structure closer to zero. In some embodiments of the present
invention, one object is to minimize the initial, smaller
displacement that lead to larger amplitudes of oscillation due to
greater wind-induced displacement.
[0039] In some embodiments, the attachment assembly of the present
invention provides additional strength (bending moments) by
relocating the tube tensioning connections longitudinally further
apart providing an improved fulcrum spacing. In some embodiments,
the attachment assembly of the present invention provides
compatibility to any current signal head support tube with bracket
arms commonly used to hang the traffic control device.
[0040] FIG. 1 represents a right side perspective of an embodiment
of an attachment assembly 10 for connecting a traffic control
device to a mast arm 42 of a traffic signal support structure. The
attachment assembly 10 includes a mast arm saddle or plate 12 and a
swivel plate 14. The mast arm saddle 12 and the swivel plate 14 may
be provided so that when the assembly 10 is connected to the mast
arm 42, one or both of the mast arm saddle 12 and the swivel plate
14 are flexible. A cable 16 operably connects the mast arm saddle
12 to the mast arm 42. A plurality of connectors connects the
attachment assembly 10 together as described in more detail
below.
[0041] In some embodiments, both the mast arm saddle 12 and the
swivel plate 14 may be fabricated out of metal, for example, a
weather resistant stainless steel plate in a thickness ranging from
1/8'' to 5/16'' pending upon design criteria based upon different
wind zones. Other materials such as flexible engineered plastics
may also be desirable in some applications. In some embodiments,
combinations of materials may be used. The mast arm saddle 12 and
the swivel plate 14 may be fabricated using computer controlled
(CNC), laser or water jet cutting. Other methods known to one
skilled in the art may also be used to fabricate the mast arm
saddle 12 and the swivel plate 14, including, but not limited to
stamp and punch pressing. In some embodiments, the mast arm saddle
12 may be first cut out as a flat plate with a plurality of
apertures. The apertures may include one or more adjustment slots
23 and a plurality of apertures 25 for receiving fasteners
therethrough for connecting the mast arm saddle 12 to the swivel
plate 14 (further explained below). The cable 16 may also be
threaded through some of the apertures. The mast arm saddle 12 may
also include an opening 26 that is sized and shaped to receive
wires for electrical connections for the traffic control
device.
[0042] After cutting the mast arm saddle 12 from the flat plate,
one or more mast arm engagement flanges 40 may be cold bent
approximately 90.degree. downward from a first surface 13 of the
saddle 12. In some embodiments, the engagement flanges 40 may be
positioned at opposite ends 19 of the saddle 12. Ends 41 of the
engagement flanges 40 may each include a curved portion that is
adapted to contact a curved portion of the mast arm 42 when the
mast arm saddle 12 is positioned on the mast arm 42, for example,
when the mast arm 42 is curved. The ends 41 of the engagement
flanges 40 may be configured to have any shape that conforms to the
shape of the mast arm 42. In some embodiments, the ends 41 may be
angular or straight. In higher wind zones or in the case of lighter
mast arm construction (thinner material) it may be desirable to
incorporate pads to the mast arm engagement flanges 40 to
distribute surface pressures between the mast arm saddle 12 and the
mast arm 42. As shown in FIG. 4, the ends 41 of the engagement
flanges 40 contact the mast arm 42 and the first surface 13 of the
mast arm saddle 12 faces the mast arm 42. The first surface 13 of
the mast arm saddle 12 is spaced apart from the mast arm 42 such
that a gap 65 exists between the mast arm saddle 12 and the mast
arm 42 to accommodate flexing of the mast arm saddle 12. In some
embodiments, the engagement flange 40 may be positioned other than
at the opposite ends 19 of the mast arm saddle 12. By way of
non-limiting example, one or more engagement flanges 40 may be
positioned away from the ends 19 of the mast arm saddle 12 at a
central position or offset from the center. Additionally, in some
embodiments, an acute angle connection flange 38 may be cold bent
approximately 10.degree. to 20.degree. upward from a second surface
15 of the saddle 12 pending final design criteria as shown in FIGS.
1, 3A and 3B.
[0043] FIGS. 3A and 3B are isometric views showing the mast arm
saddle 12 for reference without any attachments. Both FIGS. 3A and
3B generally illustrate the saddle 12 post cutting and bending.
Eased-rounded edges 46 are shown and may be provided to prevent any
fraying or shear points of the cable 16. In some embodiments, the
mast arm saddle may include a "turned down" longitudinal flange
(not shown) to utilize a thinner saddle material. The longitudinal
turned down flange is free from contact with the mast arm.
[0044] The swivel plate 14 may be similarly fabricated (laser cut)
from a flat plate. The swivel plate 14 may include one or more
arcuate slots 24 for receiving fasteners therethrough for
connecting the mast arm saddle 12 to the swivel plate 14. The
swivel plate 14 may also include an opening 26 that is sized and
shaped to receive wires for electrical connections for the traffic
control device. The opening 26 in the mast arm saddle 12 and the
opening 26 in the swivel plate 14 may be aligned to facilitate
passage of the electrical connections therethrough.
[0045] The swivel plate 14 is shown for reference attached to
saddle 12 in FIG. 1 without the traffic signal tube as depicted and
more fully described in FIG. 2. As shown in FIG. 1, the swivel
plate 14 may include four arcuate slots 24 that receive bolts 32
and inverted flange nuts 30 (phantom). Vertical and in some
installations horizontal mounting is possible by utilizing slots 24
to adjust the swivel plate 14 in order to achieve the required
plumbness (vertical applications) or level (horizontal
applications). FIG. 6 is a plan view showing the swivel plate 14
without any attachments. In the embodiment shown in FIG. 6, an
expansion area 14a may be included in some embodiments for
additional flexibility of the swivel plate 14. The wire access
opening 26 and the arcuate slots 24 are also shown. Fastening
apertures 25 may be used for securing the swivel plate 14 to a
signal securing tube 44 using utility U-bolts 20 (shown in FIG. 2)
or flexible signal brackets 17 (shown in FIGS. 7 and 8.).
[0046] FIG. 5 is a cross sectional view taken along 5 of FIG. 1.
For reference, a portion of the mast arm saddle 12 and swivel plate
14 is shown with an exemplary connection. By way of non-limiting
example, an inverted flange nut 30 may be installed over washer 33
secured to the mast arm saddle 12. In some embodiments, washers,
bushings, coupling nuts or other fasteners may also be used. The
purpose of inverting the flange nut 30 is dual functioning; first
to allow the mast arm saddle 12 and the swivel plate 14 to move
relative to one another by the separation of the second surface 15
of the mast arm saddle 12 from a first surface 53 of the swivel
plate 14, creating a displacement gap 55. The term "displacement"
as used herein is defined as the distance of a flexible body from
its equilibrium. In some embodiments, it may be preferable to
increase a length of a gap 55a to provide additional displacement
and/or clearance of the cable 16. In contrast to the typical prior
art connections where the saddle and plate faces are typically
closely positioned adjacent to each other for rigidity with no
space therebetween, the flange nut 30 and washer 33 positioned
between the mast arm saddle 12 and the swivel plate 14 create the
displacement gap 55 at each moment connection area that allow one
or both the mast arm saddle 12 and swivel plate 14 to flex
independent from each other. The second function is to capture the
cable 16 temporarily while pre-tensioning as described with
reference to installation of the attachment assembly 10. The final
securement of the swivel plate 14 will prevent release of a cable
loop 19.
[0047] FIGS. 2, 7, 11A and 11B illustrate the mast arm saddle 12
shown connected to the mast arm 42 with the curved surface 41 of
the engagement flange 40 positioned against the mast arm 42. FIG. 2
illustrates a conventional signal support tube 44 connected to
flexible the swivel plate 14 without the traffic control device for
clarity. FIG. 2 depicts a portional side view of the attachment
assembly 10 showing the displacement gap 55 between the mast arm
saddle 12 and the swivel plate 14. FIG. 2 also illustrates a gap 65
between the swivel plate and the support tube 44. For reference,
the signal support tube 44 is sometimes channeled and in most
instances gusseted for added strength--both common and typical to
mast arm traffic signal mounting hardware. The tube 44 generally
includes a bottom bracket and a top bracket with a traffic control
device between the two brackets (FIG. 11A). In some embodiments, it
may be preferable to replace the rigid tube and cast aluminum
brackets with flexible rectangular stainless steel signal bracket
17 with at least one cold bent approximate 90.degree. integral
support arm at one end and another support arm opposite of the
first support arm with a means of adjustment to secure preferably a
single unit signal housing 63 with integral terminal 50 as shown in
the embodiment in FIG. 11B. In some embodiments, the single unit
signal housing 63 may include a backplate. The signal bracket 17
may be connectable to the swivel plate 14, and in some embodiments
is connectable to the saddle plate 12 only, and perform as a swivel
and a means for supporting a traffic control device. In the
embodiment shown in FIG. 11B, the signal bracket 17 is a metal
rectangular single piece bracket. In some instances it may be
preferable to have at least one 90.degree. return integral to the
longitudinal portion and another return not integral but adaptable
to the longitudinal portion. The bracket 17 is secured to the
swivel plate 14 utilizing a clamping plate 48 and fasteners 49.
Longitudinal adjustments, both vertical and horizontal
applications, is provided by sliding the bracket 17 in the
desirable direction between the swivel plate 14 and clamp plates 48
prior to final tightening of fasteners 49.
[0048] Final electrical connections are made utilizing conductors
52 into terminal housing 50 through waterproof grommet 51 to
connection block (not shown) located in terminal housing 50.
Embodiments of the attachment assembly 10 are also adaptable to be
used with common tube, brackets, traffic control device and a means
to provide wire access.
[0049] The embodiments, for example as shown in FIGS. 2, 7, 11A,
11B, and 12-15 take into account the mass of the bracket(s), tube
44 or signal bracket 17 and traffic control device as it relates to
gravitational and wind loading in respect to acceleration and
deceleration forces upon the saddle plate 12 and swivel plate 14
and sometimes the signal bracket 17. The flexibility and the
resiliency of the attachment assembly 10 are a function of the mass
of the traffic control device, the configuration of the swivel
plate, the length of the swivel plate and/or the signal bracket,
the thickness of the swivel plate and/or the signal bracket, the
width of the mast arm saddle and the thickness of the mast arm
saddle. The first amount of flexibility is determined by the
material thickness and the amount of lateral clearance in the gap
65 between the second face 57 of the swivel plate 14 and the tube
44 or the signal bracket 17. The gap 65 is created by either a
saddle 18 against the support tube 44 and/or stand off nuts 36 and
is directly proportional to the overall length of the swivel plate
14. The tube 44 is secured to swivel plate 14 utilizing U-bolts 20
around the tube 44, through the saddle 18 and connected with
appropriate fasteners. A similar gap 65 is created between the
swivel plate 14 and the flexible signal bracket 17 described with
reference to FIG. 11B. The second amount of flexibility is
determined by the configuration of the swivel plate.
[0050] An exemplary method for installing the attachment assembly
10 is described. One skilled in the art will recognize that other
methods may also be used, including, but not limited to metal bands
or bent to fit bolts. Prior to installation on the mast arm 42, a
swedge bolt 28 connected to the cable 16 is inserted into the
adjustment slot 23 of the angle connection flange 38 of the mast
arm saddle 12 and is temporarily attached utilizing washer 33 and
nut 34. The connection flange 38 of the mast arm saddle 12 has an
upward acute plane to lessen cable stress from different diameter
mast arms. It is important at this stage to just start nut 34
preferably less than a full nut thread length so as to be able,
upon tensioning, achieve the greater amount of tensioning range.
The free end of the cable 16 is inserted through a cable clamp 22
connected to the mast arm saddle 12, then threaded upward through
the slot 23 over the second surface 15 of the saddle 12 to the slot
23a then through the slot 23a downward continuing along the first
surface 13 of the mast arm saddle 12 and outward and through a
clamp 22a. At this stage the cable 16 now has a loop 19 which is
temporarily secured to the attachment assembly 10.
[0051] Prior to securing to the attachment assembly 10 utilizing
inverted flange nuts 30 as shown in FIG. 1, the saddle 12 is placed
temporarily on top of mast arm 42 utilizing the engagement flanges
40. The loop 19 is brought up over the mast arm 42 and hooked
around inverted flange nuts 30, see also FIG. 5. Slack in the cable
16 may then be removed by hand pulling of the cable end 16a to
pre-tension the cable 16. As shown in FIG. 7, the cable 16 extends
a length A along the second surface 15 of the mast arm saddle 12, a
length B along the first surface 13 of the mast arm saddle 12 and
through slots 23 and 23a in the mast arm saddle 12 having a length
C.
[0052] FIG. 8 illustrates a cross sectional view taken along line
A-A of FIG. 7 and showing the mast arm saddle 12 positioned on top
of the mast arm 42. A small gap 101 may be provided between the
cable 16 and the second surface 15 where the cable 16 extends the
length A between the slots 23 and 23a and the cable clamp 22a is
temporarily tightened. The cable clamps 22, 22a may include a
standard cable saddle depending upon the wind loading at a
particular location.
[0053] FIG. 9 illustrates a tool 102 that may be used to apply
pre-tension between the mast arm saddle 12 and the mast arm 42. The
tool 102 includes a handle 103 and a lever plate 105. In some
embodiments, the lever plate 105 is integrally formed with the
handle 103. The lever plate 105 has a first end 104 having a chisel
shape to facilitate placement of the end 104 between the cable 16
and the second surface 15 of the mast arm saddle 12. The lever
plate 105 includes a second end 106 that may include a rounded
shape that allows for less stress on the cable 16.
[0054] FIG. 10 illustrates use of the tool 102 with the mast arm
assembly 10. As shown, the lever plate 105 of the tool 102 may be
inserted into the gap 101 and rotated until cable slack is removed
from the cable 16 and a firm tension is applied. While maintaining
the tension, cable clamp 22 is tightened. The tool 102 is removed
and clamp 22a is loosened. Extra slack is removed by pulling on
cable end 16a and then secured by retightening clamp 22a. The mast
arm saddle 12 is rotated on the mast arm 42 to the desired vertical
plane relative to the roadway below. In some instances, depending
on the shape of the mast arm 42, i.e., a 12 sided polygon, it may
be difficult to rotate the mast arm saddle 12. By loosening the
clamp 22, only the tensioning forces between the tool-leverage and
the hand tensioning of the cable slack described above remain and
should minimize any difficulty in rotating the mast arm saddle 12.
The swedge bolt 28 for the cable 16 is tightened to cinch the mast
arm saddle 12 to the mast arm 42.
[0055] In some embodiments, the traffic control device 63 is
connected to the support tube 44 using the appropriate fasteners.
Then the tube 44 is connected to the swivel plate 14 for example
using u-bolts 20 connected to saddles 18 as shown in FIG. 11A. The
swivel plate 14 with the traffic control device 63 connected
thereto is connected to the mast arm saddle 12 and the slots 24 of
the swivel plate 14 are used to adjust the traffic control device
to be level or plumb.
[0056] FIG. 12 illustrates an embodiment of an end bracket assembly
100 that may be part of the attachment assembly 10. For clarity,
the traffic control device that is mounted to the mast arm 42 using
the end bracket assembly 100 has been omitted. In some embodiments
using the end bracket assembly 100, one mast arm saddle or plate
112 may be operably connected to the traffic control device at each
end of the traffic control device, for example when the traffic
control device is horizontally mounted on the mast arm 42. As shown
in FIG. 12, the mast arm saddle 112 includes a first face 113 that
is spaced apart from the mast arm 42 by a displacement gap 155.
Engagement portions 141 of the mast arm saddle 112 are adapted to
contact the mast arm 42. The gap 155 allows the mast arm saddle 112
to flex in response to wind force. The mast arm saddle 112 may
include an angled connection flange 138 extending from the
engagement portions 141. Each connection flange 138 may include one
or more apertures 139 through with a cable 116 may be extended and
secured to connect the saddle 112 to the mast arm 42.
[0057] As shown in FIG. 12, the mast arm saddle 112 is fastened to
the mast arm 42 using adjustment holes 125a and a cable 116
inserted through the adjustment holes 125a. The cable 116 may be
adjustably threaded through the holes 125a and secured to angle
connection flanges 138 similar to the securement of the cable 16
described above. Each angled connection flange may include a
plurality of adjustment holes 125a. A flexible signal bracket 117
may be attached to the mast arm saddle 112 utilizing a bolt 132, a
washer 133 and a lock nut 134. Prior to finally securing the signal
bracket 117, the attachment assembly 100 may be leveled utilizing
apertures 25a of a vertical flange 117a. The vertical flange 117a
is designed to flex in the direction of the wind force and in the
process respond dynamically as described above. A signal attachment
plate 117b of the signal bracket 117 includes adjustment apertures
125a to connect the traffic control device to the signal bracket
117. The mast arm saddle 112 may be manufactured using materials
and methods similar to those described above for the mast arm
saddle 12.
[0058] FIG. 13 illustrates an isometric view of an embodiment of a
swivel plate 214. The swivel plate 214 may be attached to a mast
arm saddle 12, 112 as described herein or to a conventional mast
arm saddle. The swivel plate 214 may be used with a conventional
rigid tube type signal mounting devices. In some embodiments the
swivel plate 214 dynamically responds to vertical or horizontal
displacements. In some embodiments, the swivel plate 214
dynamically responds to both vertical and horizontal displacements.
The swivel plate 214 may include one or more arcuate slots 224 for
receiving fasteners therethrough for connecting the mast arm saddle
to the swivel plate 214. The swivel plate 214 may also include an
opening 226 that is sized and shaped to receive wires for
electrical connections for the traffic control device. The swivel
plate 214 may include four arcuate slots 224 that receive bolts 32
and inverted flange nuts 30 similar to the connection illustrated
in FIG. 5. Vertical and in some installations horizontal mounting
is possible by utilizing slots 224 to adjust the swivel plate 214
in order to achieve the required plumbness (vertical applications)
or level (horizontal applications). Fastening apertures 225b may be
used for securing the swivel plate 214 to a signal securing tube 44
using utility U-bolts 20 (similar to the connection shown in FIG.
2) or flexible signal brackets 17 (similar to the connection shown
in FIGS. 11 and 12.) Portion A of the swivel plate 214 is adapted
to perform the same basic function and mast arm saddle attachment
as described above with reference to swivel plate 14. Portion A
includes a first surface 253 and a second surface 257. The first
surface 253 may be spaced apart from the second surface 15 of the
mast arm saddle 12 when the mast arm saddle 12 and the swivel plate
214 are operably connected to allow one or both of the mast arm
saddle 12 and the swivel plate 214 to flex. In some embodiments,
the first surface 253 of the swivel plate 214 is adapted to be
oriented toward the mast arm 42 and the first surface 253 may
extend substantially parallel to a longitudinal axis of the mast
arm 42 or substantially perpendicular a longitudinal axis of the
mast arm 42 depending on the orientation of the traffic control
assembly. In some embodiments, such as windy environments, the
length of the portion A and/or portion D may be longitudinally
extended (proportional to the remainder of the swivel plate 214) to
increase flexibility of the swivel plate 214.
[0059] Portion B descends from portion A at an angle 231. In some
embodiments, the angle 231 may be about 10-15.degree., about
20.degree., about 25.degree. or 30.degree. or greater than
30.degree.. The angle 231 may depend on the weight of the traffic
control device attached thereto and/or the wind zones and/or the
amount of flexibility required dependent on the wind zones. Portion
C ascends from portion A at an angle 232. The angle 232 may be
equal to, greater than or less than the angle 231. The angle 232
will depend on the desired amount of flexibility of the attachment
assembly and the weight of the traffic control assembly and/or the
position of the traffic control assembly. In some embodiments, the
angle 232 may be greater than the angle 231 to help even the weight
distribution. The lengths of portion B and portion C may be the
same or portion C may be shorter or longer than portion B depending
on the degree of flexibility required for the attachment
assembly.
[0060] Portion D may extend substantially parallel to portion A in
some embodiments. Even if the portions B and C have different
lengths or extend at different angles from portion A, portion D may
still be considered to extend substantially parallel to portion A.
Portion D includes a first surface 243 facing the portion A and a
second surface 245 facing toward a traffic control assembly. As
shown in FIG. 9, portion D may have a length that is longer than
portion A. In some embodiments, the lengths of portion A and
portion D may be the same or portion A may be shorter than portion
D. Portion D by utilizing the outer attachment holes 225 may be
connected to the bracket 17 or the support tube 44 similar to the
embodiments described above. In some embodiments, where additional
flexibility is desired, the signal bracket (not shown) can be
installed so that a displacement gap is provided between the
bracket and the swivel plate 214. The swivel plate 214 may be
fabricated out of materials similar to the materials describe above
for the swivel plate 14. The swivel plate 214 may be fabricated
similar to the methods described above. In some embodiments, the
swivel plate 214 may be formed as a unitary piece, first cut out as
a flat plate with a plurality of apertures. Portions B and C may be
cold bent at an angle extending from portion A. Portion D may be
cold bent at an angle extend from portions B and C so that ends 235
of the plate 214 meet or are positioned adjacent to each other so
that a generally four sided plate is formed. In some embodiments,
the ends 235 are spaced apart so that a gap is formed in the
portion D. In some embodiments, portion D may include a joint 237
that is welded together at the ends 235 for added strength in high
wind areas. A displacement gap 285 extends between the portions A
and D that is configured to allow the swivel plate 214 to flex. The
swivel plate 214 may be connected to the saddle plate 12 described
above and may include a displacement gap 255 between the saddle
plate 12 and the swivel plate 214 as shown in FIG. 14.
[0061] In some embodiments, the swivel plate 214 may be a tetragon,
a trapezoid, a parallelogram, a rectangle or any other four sided
configuration. In some embodiments, one or more of the portions A-D
of the swivel plate 214 may include a bend or a curve. In some
embodiments, the portions A and D may be substantially parallel and
the portions B and C may be curved.
[0062] FIG. 15 illustrates an isometric view of another embodiment
of a swivel plate 314 in accordance with the present invention. The
swivel plate 314 is designed to be used with the mast arm saddles
described herein or with traditional rigid mast arm saddles. The
swivel plate 314 may be used with traditional support tubes and/or
brackets as well as with flexible brackets described herein.
Similar to the embodiments described above, the swivel plate 314
may act as a dampener for reducing harmful oscillations. The swivel
plate 314 includes a first plate 340 and a second plate 345. A
flange 350 extends between the first and second plates 340, 345. In
some embodiments, the first and second plates 340, 345 extend
substantially parallel to each other and the flange 350 extends
substantially perpendicular to the first and second plates 340,
345. In other embodiments, the first and second plates 340, 345 and
the flange 350 may have other configurations. In some embodiments,
the flange 350 may be centrally positioned with respect to one or
both of the first plate 340 and the second plate 345. In some
embodiments, the flange 350 may be offset from center of one or
both of the first plate 340 and the second plate 345. The first
plate 340 is adapted to be connected to a mast arm saddle, such as
mast arm saddle 12 described above, that is connected to the mast
arm 42. The first plate 340 includes a plurality of arcuate slots
324 for connection of the first plate 340 to the mast arm saddle.
The first plate includes a first surface 353 and a second surface
357. The first surface 353 may be facing and spaced apart from the
second surface 15 of the mast arm saddle 12 when the mast arm
saddle 12 and the swivel plate 314 are operably connected to allow
one or both of the mast arm saddle 12 and the swivel plate 314 to
flex. In some embodiments, the first surface 353 of the swivel
plate 314 is adapted to be oriented toward the mast arm 42.
[0063] The second plate 345 includes a plurality of openings 325
for connection of the second plate 345 to a bracket or support tube
connected to a traffic control device. The second plate 345
includes a first surface 343 facing the second surface 357 of the
first plate 340 of the swivel plate 314 and a second surface 347
facing toward a traffic control assembly. As shown in FIG. 15, the
second plate 345 may have a length that is longer than the first
plate 340. The second plate 345 may be lengthened to increase
flexibility of the swivel plate 314 as shown by dashed lines 345a.
The flange 350 may also be lengthened to increase flexibility. A
displacement gap 385 is formed between the first plate 340 and the
second plate 345 that also allow the swivel plate 314 to flex. The
swivel plate 314 may be made out of flexible metals such as
stainless steel and fabricated by welding, cut and fold, injection
molding, bolting and combinations thereof.
[0064] While the embodiments here in have been described with
reference to use with a mast arm system, the embodiments may also
be used with lighting poles and other structures, such as street
lighting and high mast interstate lighting systems. The embodiments
described herein may also be used with signs.
[0065] The above Figures and disclosure are intended to be
illustrative and not exhaustive. This description will suggest many
variations and alternatives to one of ordinary skill in the art.
All such variations and alternatives are intended to be encompassed
within the scope of the attached claims. Those familiar with the
art may recognize other equivalents to the specific embodiments
described herein which equivalents are also intended to be
encompassed by the attached claims.
* * * * *