U.S. patent application number 12/833079 was filed with the patent office on 2011-01-20 for expansion splice plate for a cable tray run.
This patent application is currently assigned to COOPER TECHNOLOGIES COMPANY. Invention is credited to Robert David Smith, Brandon Michael Tally.
Application Number | 20110013978 12/833079 |
Document ID | / |
Family ID | 43465423 |
Filed Date | 2011-01-20 |
United States Patent
Application |
20110013978 |
Kind Code |
A1 |
Smith; Robert David ; et
al. |
January 20, 2011 |
EXPANSION SPLICE PLATE FOR A CABLE TRAY RUN
Abstract
A cable tray expansion splice plate for connecting first and
second cable tray sections end-to-end is disclosed. The splice
plate includes an elongate body having a central section, an upper
flange section, and a lower flange section. In one embodiment, the
lower flange section defines a channel for receiving components of
the first and second cable tray sections such that the lower flange
section underlies the components. Fastener openings in the central
section and the lower flange section receive fasteners to fasten
the body to the cable tray sections. These openings include slots
which permit the cable tray sections to move relative to one
another in a longitudinal direction.
Inventors: |
Smith; Robert David;
(Spring, TX) ; Tally; Brandon Michael;
(Greenville, IL) |
Correspondence
Address: |
SENNIGER POWERS LLP (BLN)
100 NORTH BROADWAY, 17TH FLOOR
ST LOUIS
MO
63102
US
|
Assignee: |
COOPER TECHNOLOGIES COMPANY
Houston
TX
|
Family ID: |
43465423 |
Appl. No.: |
12/833079 |
Filed: |
July 9, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61225769 |
Jul 15, 2009 |
|
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|
Current U.S.
Class: |
403/306 |
Current CPC
Class: |
Y10T 403/57 20150115;
F16L 3/00 20130101; Y10T 29/49947 20150115; H02G 3/0608 20130101;
Y10T 403/5741 20150115 |
Class at
Publication: |
403/306 |
International
Class: |
F16G 11/00 20060101
F16G011/00 |
Claims
1. A cable tray expansion splice plate for connecting first and
second cable tray sections end-to-end, said splice plate comprising
an elongate body having opposite ends, a generally planar central
section, an upper flange section extending laterally outward from
an upper end of the central section, and a lower flange section
extending laterally inward from a lower end of the central section,
the lower flange section defining a channel for receiving
components of the first and second cable tray sections such that
the lower flange section underlies the components, a first set of
openings in the central section and the lower flange section for
receiving fasteners to fasten the body to the first cable tray
section, and a second set of openings in the central section and
the lower flange section for receiving fasteners to fasten the body
to the second cable tray section, each opening of the first set of
openings comprising a slot having a major axis extending lengthwise
of the body to permit movement of the cable tray sections relative
to one another in a direction extending longitudinally of the cable
tray sections.
2. The splice plate of claim 1, wherein each opening of the second
set comprises a slot having a major axis extending lengthwise of
the body to permit movement of the cable tray sections relative to
one another in a direction extending longitudinally of the cable
tray sections.
3. The splice plate of claim 2, further comprising a third set of
openings in the central section and the lower flange section for
receiving fasteners to fasten the body to the second cable tray
section, each opening of the third set comprising a slot having a
major axis extending lengthwise of the body to permit movement of
the cable tray sections relative to one another in a direction
extending longitudinally of the cable tray sections.
4. The splice plate of claim 3, wherein the lower flange section of
the body comprises a heel portion projecting outward from the
central section and a toe portion projecting inward from the heel
portion to a location inboard of the central section.
5. The splice plate of claim 4, wherein each of the first, second,
and third sets of openings includes two slots in the central
section and one slot in the toe portion of the lower flange
section.
6. The splice plate of claim 5, wherein the slots of each set of
the first, second, and third sets lie in a single plane extending
transversely of the splice plate.
7. The splice plate of claim 1, wherein the lower flange section of
the body comprises a heel portion projecting in an outboard
direction from the central section and a toe portion projecting in
an inboard direction from the heel portion to a location inboard of
the central section.
8. The splice plate of claim 7, wherein each of the first and
second sets of openings includes two openings in the central
section and one opening in the toe portion of the lower flange
section.
9. The splice plate of claim 8, wherein the openings of each set of
the first and second sets lie in a single plane extending
transversely of the splice plate.
10. Two splice plates as set forth in claim 1 connecting two cable
tray sections end to end.
11. A cable tray expansion splice plate for connecting first and
second cable tray sections end-to-end, said splice plate comprising
an elongate body having opposite ends, a generally planar central
section, an upper flange section extending laterally outward from
an upper end of the central section, and a lower flange section
extending laterally inward from a lower end of the central section,
a first set of openings in the central section and the lower flange
section for receiving fasteners to fasten the body to the first
cable tray section, and a second set of openings in the central
section and the lower flange section for receiving fasteners to
fasten the body to the second cable tray section, each opening of
the first and second sets of openings comprising a slot having a
major axis extending lengthwise of the body to permit movement of
the cable tray sections relative to one another in a direction
extending longitudinally of the cable tray sections.
12. The splice plate of claim 11, wherein the lower flange section
of the body defines a channel for receiving components of the first
and second cable tray sections such that the lower flange section
underlies the components.
13. The splice plate of claim 12, wherein the lower flange section
of the body comprises a heel portion projecting outward from the
central section and a toe portion projecting inward from the heel
portion to a location inboard of the central section.
14. The splice plate of claim 13, wherein each of the first and
second sets of openings includes two slots in the central section
and one slot in the toe portion of the lower flange section.
15. The splice plate of claim 14, wherein the slots of each set of
the first and second sets lie in a single plane extending
transversely of the splice plate.
16. The splice plate of claim 11, further comprising a third set of
openings in the central section and the lower flange section for
receiving fasteners to fasten the body to the second cable tray
section, each opening of the third set comprising a slot having a
major axis extending lengthwise of the body to permit movement of
the cable tray sections relative to one another in a direction
extending longitudinally of the cable tray sections.
17. The splice plate of claim 16, wherein the lower flange section
of the body defines a channel for receiving components of the first
and second cable tray sections such that the lower flange section
underlies the components.
18. The splice plate of claim 17, wherein each of the first,
second, and third sets of openings includes two openings in the
central section and one opening in the lower flange section.
19. The splice plate of claim 18, wherein the slots of each set of
the first, second, and third sets lie in a single plane extending
transversely of the splice plate.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from U.S. Patent
Application No. 61/225,769 (provisional), filed Jul. 15, 2009,
which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention generally relates to an expansion
splice plate for a cable tray run.
BACKGROUND OF THE INVENTION
[0003] Ladder-type cable tray is used by industry to support
electrical cable. A length or section of ladder cable tray
comprises a pair of side rails connected by cable-supporting rungs
extending between the rails at intervals along the tray. Cable tray
sections are spliced together using splice plates to form a cable
tray run. Splicing cable tray sections using expansion splice
plates is required when installing the cable tray run outdoors
where temperature variations may cause thermal expansion and
contraction of the cable tray sections.
[0004] FIG. 1 illustrates a conventional expansion splice plate for
fiberglass cable tray. The splice plate, made of fiberglass, is
generally L-shaped and is configured to be secured to adjoining
sides (rails) of adjacent cable tray sections between upper and
lower flanges of the rails. The conventional expansion splice plate
includes a first set of openings for receiving fasteners to secure
the splice plate to a rail of one of the adjacent cable tray
sections. A second set of openings includes slot-shaped openings
for receiving fasteners to secure the splice plate to a rail of the
other of the adjacent cable tray sections. The slot-shaped openings
allow for longitudinal movement of the tray sections relative to
one another. A conventional expansion splice plate for metal cable
tray (not shown) comprises a flat metal plate with slot-shaped
fastener openings that permit longitudinal movement of the tray
sections relative to one another.
[0005] Typically, supports, such as trapeze supports, are installed
at every quarter span of the cable tray run, as illustrated in FIG.
2. However, when using the above-described conventional expansion
splice plate, a support must be installed at each end of the
adjacent tray sections to adequately support the splice. Thus, two
supports must be installed for each tray section in addition to the
support at each quarter span, making the installation process more
time-consuming and expensive. Alternatively, elimination of one or
more quarter-span supports will result in greater deflection of the
cable tray run, which is undesirable.
SUMMARY OF THE INVENTION
[0006] This invention is directed to a cable tray expansion splice
plate for connecting first and second cable tray sections
end-to-end. The splice plate comprises an elongate body having
opposite ends, a generally planar central section, an upper flange
section extending laterally outward from an upper end of the
central section, and a lower flange section extending laterally
inward from a lower end of the central section. The lower flange
section defines a channel for receiving components of the first and
second cable tray sections such that the lower flange section
underlies the components. A first set of openings is provided in
the central section and the lower flange section for receiving
fasteners to fasten the body to the first cable tray section. A
second set of openings is provided in the central section and the
lower flange section for receiving fasteners to fasten the body to
the second cable tray section. Each opening of the first set of
openings comprises a slot having a major axis extending lengthwise
of the body to permit movement of the cable tray sections relative
to one another in a direction extending longitudinally of the cable
tray sections.
[0007] This invention is also directed to a cable tray expansion
splice plate having opposite ends, a generally planar central
section, an upper flange section extending laterally outward from
an upper end of the central section, and a lower flange section
extending laterally inward from a lower end of the central section.
A first set of openings is provided in the central section and the
lower flange section for receiving fasteners to fasten the body to
the first cable tray section. A second set of openings is provided
in the central section and the lower flange section for receiving
fasteners to fasten the body to the second cable tray section. Each
opening of the first and second sets of openings comprises a slot
having a major axis extending lengthwise of the body to permit
movement of the cable tray sections relative to one another in a
direction extending longitudinally of the cable tray sections.
[0008] Other objects and features will be in part apparent and in
part pointed out hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 depicts a conventional expansion splice plate for
fiberglass cable tray;
[0010] FIG. 2 is a schematic illustrating typical locations of
supports for the cable tray run when using the conventional
expansion splice plates of FIG. 1;
[0011] FIG. 3 is a perspective view of two sections of ladder cable
tray connected by expansion splice plates of the present
invention;
[0012] FIG. 4 is a view similar to FIG. 3 showing a splice plate of
the present invention and fasteners exploded away from rails of the
cable tray;
[0013] FIG. 5 is a side elevation of an expansion splice plate of
FIG. 3;
[0014] FIG. 6 is a top plan of the splice plate of FIG. 5;
[0015] FIG. 7 is an end view of the splice plate of FIG. 5;
[0016] FIGS. 8A-8E are schematic views illustrating steps for
splicing adjacent ladder cable tray sections using the expansion
splice plates of FIG. 3; and
[0017] FIG. 9 is a schematic diagram illustrating locations of
supports for the cable tray run when using the expansion splice
plates of FIG. 3.
[0018] Corresponding reference characters indicate corresponding
parts throughout the drawings.
DETAILED DESCRIPTION OF THE DRAWINGS
[0019] FIGS. 3 and 4 illustrate two sections 10A, 10B of ladder
cable tray 10 connected by expansion splice plates 20 of the
present invention. Each cable tray section includes two parallel
rails 24 forming the sides of the cable tray section, and a
plurality of cable-supporting rungs 26 extending between the rails
24 at intervals spaced lengthwise of the section. Each rail 24
comprises a generally vertical web 30, an upper generally
horizontal flange 32 at the upper end of the web, and a lower
generally horizontal flange 34 at the lower end of the web. The
rungs 26 are secured (e.g., by welding) to inboard portions of the
lower flanges 34 extending inboard from respective webs.
Pre-drilled fastener holes 36 (FIG. 8A) are provided adjacent
opposite ends of the rails for use in connecting the cable tray
sections 10A, 10B to one another via splice plates, as will be
described. In the illustrated embodiment, each rail 24 has three
pre-drilled holes adjacent each of its ends. Two of the three holes
36 are in the web 30 of the rail, and one of the holes 36 is in the
outboard portion of the lower flange 34. All three holes 36 lie
substantially in the same vertical plane. This arrangement can
vary. The length of each manufactured cable tray section may also
vary (e.g., from 10-30 feet). Sections are often cut to fit in the
field to varying lengths.
[0020] Referring to FIGS. 5-7, each expansion splice plate 20
includes an elongate body 38 having opposite ends 40. The body 38
includes a generally vertical rectangular planar central section
42, a top generally horizontal flange section 44 extending
laterally outward (i.e., in an outboard direction) from an upper
end of the central section, and a bottom channel section 48 at a
lower end of the central section. The bottom channel section 48 has
a heel portion 52 projecting laterally outward (i.e., in an
outboard direction) from the central section 42 and a generally
horizontal toe portion 56 projecting laterally inward (i.e., in an
inboard direction) from the heel portion to a location inboard of
the central section 42. The heel and toe portions 52, 56 define a
channel 60 for receiving components of the two cable tray sections
10A, 10B. In the illustrated embodiment, these components are the
outboard portions of the lower flanges 34 of the rails 24 of the
two cable tray sections 10A, 10B, as described below.
[0021] The splice plates 20 are sized and dimensioned to have a
relatively close abutting fit with the cable tray sections 10A, 10B
to be connected by the plates. In the illustrated embodiment, shown
in FIGS. 3 and 7, each plate 20 is sized and dimensioned to be
placed in a splicing position in which it is nested between the
upper and lower flanges 32, 34 of the two cable tray sections. In
this position, the top flange section 44 of the plate extends
generally parallel to and immediately below (desirably abutting)
the upper flange 32 of the two cable tray sections 10A, 10B; the
central section 42 of the plate 20 extends generally parallel to
and immediately adjacent (desirably abutting) the vertical webs 30
of the cable tray sections on the outboard side of the rails 24;
and the outboard portions of the lower flanges 34 of the cable tray
sections are received in the channel 60 formed by the bottom
channel section 48 of the splice plate such that the toe portion 56
underlies (desirably abutting) the lower flanges 34 of the cable
tray sections. The fit is such that the top, central, and bottom
sections 44, 42, 48 of the splice plates 20 are in contact (or near
contact) with respective surfaces of the cable tray sections 10A,
10B.
[0022] Referring to FIGS. 5 and 6, the splice plate 20 includes
three sets of openings 68a, 68b, 68c for receiving fasteners to
secure the splice plate to adjacent cable tray sections 10A, 10B.
The sets of fastener openings 68a, 68b, 68c are spaced apart along
a length L1 of the splice plate 20. In the illustrated embodiment,
each set of openings includes three elongate, slot-shaped openings
70, two of which are in the central section 42 and one of which is
in the toe portion 56 of the bottom channel section 48. The slot
openings 70 have major axes 80 extending along the length of the
splice plate 10 to allow for relative movement between the cable
tray sections 10A, 10B. The slot openings 70 have substantially the
same length L2 (e.g., 1.5 in.). The three slot openings 70 in each
respective set 68a, 68b, 68c have centers that are substantially
aligned along the height H of the splice plate 20, i.e., the three
slot openings of each set lie in a single plane 86 extending
transverse to the splice plate through the slot centers. The slot
openings 70 may have other configurations and may be arranged on
the splice plate in other ways without departing from the scope of
the invention.
[0023] In the illustrated embodiment, the vertical centerline 86 of
the slot set 68a is spaced a distance D1 from the left end of the
splice plate 20; the vertical centerline 86 of slot set 68b is
spaced a distance D2 to the right of set 68a; and the vertical
centerline 86 of slot set 68c is spaced a distance D3 to the right
of set 68c and a distance D4 from the right end of the splice plate
20. As shown best in FIG. 7, the slot openings 70 in the toe
portion 56 of the splice plate are offset a horizontal distance D5
outboard from the central section 42 of the plate. When the splice
plate 20 is in its splicing position (FIGS. 3 and 7), the fastener
openings 70 of sets 68a and 68b are positioned to align with the
pre-drilled fastener holes 36 (FIG. 8A) in the webs 30 and lower
flanges 34 of adjacent rails 24 of the two cable tray sections 10A,
10B to be spliced together. It is understood that the number and
arrangement of fastener openings 70 in the splice plates 20 and
aligned fastener holes in the cable tray sections may vary without
departing from the scope of the present invention.
[0024] FIGS. 8A-8E illustrate exemplary steps for connecting the
two cable tray sections 10A, 10B using two splice plates 20
positioned along opposite sides of the cable tray sections.
[0025] In step 8A, left and right cable tray sections 10A, 10B are
positioned end to end with a gap G between the two sections. The
gap G has a suitable width (e.g., 0.0 to 1.0 in.). The right cable
tray section 10B is marked along lines 90 spaced a distance D6 from
the left end of the cable tray section. (FIG. 8A shows only one
mark 90 at one side of cable tray section 10B. A similar mark is
made on the opposite side of the cable tray section 10B.) Distance
D6 is such that when the splice plate is placed in its splicing
position as shown in FIG. 8C, the pre-drilled fastener holes 36 of
the two cable tray sections are located at the rights ends of
respective slot openings 70 of sets 68a and 68b, and the line 90 is
located at the right ends of the slot openings 70 of set 68c.
[0026] In step 8B, grease is applied to the surfaces of the cable
tray sections 10A, 10B to be contacted by the two expansion splice
plates 20 to facilitate relative movement between the plates and
the sections. Desirably, these surfaces include the outboard
surfaces of the webs 30 and the upper and lower flanges 32, 34 of
the two cable tray sections.
[0027] In FIG. 8C, the splice plates 20 are placed in their
splicing positions in which the slot openings 70 in sets 68a, 68b
are aligned with corresponding pre-drilled fastener holes in the
webs and lower flanges of the rails of the two cable sections 10A,
10B, and the slot openings 20 in set 68c are aligned with the mark
line 90. Additional fastener holes 94 are drilled in the rails at
locations corresponding to the mark line 90 and fastener openings
of set 68c. (FIG. 8C shows only one splice plate at one side of
cable tray sections 10A, 10B. A second splice plate is similarly
positioned on the opposite side of the cable tray sections, and
similar fastener holes are drilled.)
[0028] In step 8D, fasteners 100 are installed through the slot
openings 70 of set 60a of the splice plates 20 and through aligned
pre-drilled fastener holes 36 in the web 30 and lower flange 34 of
the rails 24 of the left cable tray section. Similarly, fasteners
104 are installed through the slot openings 70 of sets 60b and 60c
of the splice plate and through aligned fastener holes 36, 94 in
the web 30 and lower flange 34 of the rail 24 of the right cable
tray section. (Only one splice plate 20 at one side of the cable
tray sections is shown in FIG. 8D; a second identical splice plate
is on the opposite side of the cable tray sections.) When the
splice plates 20 are installed, the central section 42 of each
splice plate 20 overlaps respective rails 24 of the adjacent cable
tray sections 10A, 10B on the outboard sides of the rails. The
fasteners 100, 104 function to splice the cable tray sections
together while permitting longitudinal movement of the cable tray
sections relative to one another, as during thermal expansion and
contraction of the sections.
[0029] In the illustrated embodiment, each fastener 100 comprises
an assembly including a bolt 108 and a serrated-flange hex nut 110
that threads on the bolt. Each fastener 104 comprises an assembly
including a bolt 112, an elastic stop nut 114 that threads on the
bolt, and a flat washer 116. Other fasteners may be used.
[0030] The fasteners 100, 104 are tightened after they are
installed. By way of example but not limitation, the fasteners 100
may be tightened to a torque of 50 ft/lb. In the preferred
embodiment, these fasteners 100 are tightened first and, when
tight, do not move in their respective slots 70 of set 68a. The
width of the gap G between the two cable tray sections 10A, 10B is
then set according to certain temperature parameters (e.g., highest
expected metal temperature, lowest expected metal temperature, and
metal temperature at time of installation), as will be understood
by those skilled in the art. After the gap G is set, the stop nuts
114 of the fasteners 104 are tightened until snug and then backed
off a small amount (e.g., one-quarter turn) to permit relative
movement of the bolts 112 in the slots of sets 68b and 68c. By way
of example, in an installation where the length L2 of slots 70 is
1.5 in. and the bolts 112 have a shank diameter of 0.5 in., the
range of travel of the bolts 112 in respective slots 70 is about
1.0 in.
[0031] In FIG. 8E, bonding jumpers 124 are installed to bridge the
two cable tray sections on opposite sides of the two sections.
[0032] Additional cable tray sections may be connected to sections
10A, 10B, and 10C in the manner described above to form a cable
tray run of the desired length. As shown in FIG. 9, supports 130,
e.g., trapeze supports, are installed to support the cable run.
These supports 130 are installed at regular intervals along the
cable run, such as at every quarter span of the cable tray run.
Unlike the prior art installations previously described (FIG. 2),
additional supports do not need to be installed at each end of the
adjacent tray sections because the splice plates provide adequate
support at the splice. As a result, the support locations are
easily determined, and the minimum number of supports can be
installed at the correct locations. This facilitates installation,
reduces expense, and reduces the deflection of the cable tray run
compared to a situation where the sections are supported only at
their ends.
[0033] The expansion splice plates 20 are fabricated from suitable
material. By way of example, the splice plates may be made from
fiberglass if used to connect fiberglass tray sections. On the
other hand, the splice plates may be made from heavy-gage metal if
used to connect metal cable tray. The metal may be, for example,
extruded aluminum, or it may be sheet steel bent into the shape of
the splice plate. Other ways of forming the expansion splice plate
do not depart from the scope of the present invention.
[0034] Having described an embodiment of invention in detail, it
will be apparent that modifications and variations are possible
without departing from the scope of the invention defined in the
appended claims. By way of example but not limitation, in some
embodiments (e.g., embodiments where fiberglass splice plates are
used to connect fiberglass cable tray sections), the lower flange
section 49 of the splice plate 20 may be configured to underlie the
cable tray sections 10a, 10B without forming a channel.
[0035] When introducing elements of the present invention or the
embodiment(s) thereof, the articles "a", "an", "the" and "said" are
intended to mean that there are one or more of the elements. The
terms "comprising", "including" and "having" are intended to be
inclusive and mean that there may be additional elements other than
the listed elements.
[0036] As various changes could be made in the above constructions,
products, and methods without departing from the scope of the
invention, it is intended that all matter contained in the above
description and shown in the accompanying drawings shall be
interpreted as illustrative and not in a limiting sense.
* * * * *