U.S. patent number 3,919,603 [Application Number 05/462,485] was granted by the patent office on 1975-11-11 for switchboard framework corner tie.
This patent grant is currently assigned to Westinghouse Electric Corporation. Invention is credited to Thomas E. Clark, Louis N. Ricci, John G. Salvati.
United States Patent |
3,919,603 |
Salvati , et al. |
November 11, 1975 |
Switchboard framework corner tie
Abstract
A three-phase metal-enclosed switchgear unit or assembly is
provided with a single piece or unitary corner tie for supporting
three structural members in a mutually perpendicular relationship.
Eight corner ties are necessary for each switchgear section. Each
corner tie is constructed with three mutually perpendicular leg
portions. Each leg portion comprises a generally rectangular member
having a longitudinally extending open portion the edges of the
open portion extending into outward facing flanges. Structural
members can slide onto the corner tie to be held in a mutually
perpendicular alignment. Slotted openings are provided in the
flanged portions of the corner tie through which multiple openings
in the structural members are readily accessible for rigidly
securing the corner tie to the perpendicularly disposed structural
members.
Inventors: |
Salvati; John G. (Beaver Falls,
PA), Ricci; Louis N. (Beaver Falls, PA), Clark; Thomas
E. (Beaver, PA) |
Assignee: |
Westinghouse Electric
Corporation (Pittsburgh, PA)
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Family
ID: |
26989149 |
Appl.
No.: |
05/462,485 |
Filed: |
April 19, 1974 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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334329 |
Feb 21, 1973 |
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Current U.S.
Class: |
361/605; 361/832;
220/668; 403/363; 211/182; 312/257.1 |
Current CPC
Class: |
H02B
1/01 (20130101); Y10T 403/7043 (20150115); H02B
1/014 (20130101) |
Current International
Class: |
H02B
1/00 (20060101); H02B 1/01 (20060101); H02B
001/02 () |
Field of
Search: |
;52/288,475 ;287/189,36R
;317/117,120,121 ;220/84 ;312/257R,265,140,257SK ;403/363 ;211/182
;174/129B,133B |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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961,791 |
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Jun 1964 |
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UK |
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245,703 |
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Jul 1963 |
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AU |
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Primary Examiner: Tolin; Gerald P.
Attorney, Agent or Firm: Massung; H. G.
Parent Case Text
This is a continuation of Ser. No. 334,329, filed Feb. 21, 1973,
now abandoned.
Claims
What we claim is:
1. A metal-enclosed switchgear framework comprising:
a plurality of elongated structural support members, each of said
support members having a longitudinally extending opening
therethrough from one end to the other and a first pair of
non-connected and spaced flanges disposed perpendicular to each
other and extending away from the longitudinally extending
opening,
a plurality of single piece corner ties, each of said corner ties
comprising at least three leg portions extending outwardly from a
common central portion; each of the leg portions fitting snugly
inside and retained within the longitudinal openings extending
through the associated structural support members and including a
second pair of non-connected and spaced flanges disposed
perpendicular to each other and extending outward from and outside
of the longitudinally extending opening in the associated
structural support member parallel to portions of said first pair
of flanges;
fastening means connecting said first pair of flanges to said
second pair of flanges;
said plurality of single piece corner ties supporting said
structural support members and restricting movement of each of said
structural support members to a single direction generally away
from said corner tie along the longitudinal axis of said structural
support member;
said plurality of structural support members being assembled with
said plurality of corner ties and defining a polyhedron shaped
framework with the end portions of each of said plurality of
structural support members disposed around a portion of one of the
legs of the associated corner ties; and
each of said structural support members fastened at the opposite
ends to the leg portions of a pair of said plurality of corner
ties.
2. A metal-enclosed switchgear framework, as claimed in claim 1,
wherein: said plurality of elongated structural support members
comprise, cross members having a generally rectangular tubular
configuration and including a plurality of sidewalls with the
sidewalls at one of the corners being spaced from one another to
form a longitudinally extending opening, each of said cross members
having outwardly facing perpendicular flanges extending
longitudinally along the edge of the opening, and vertical corner
post members each having a generally square tubular shape and
including a plurality of side walls with the sidewalls at one of
the corners being spaced from one another to form a longitudinally
extending opening having outward facing perpendicular flanges
formed at the edges of the opening; each of said corner ties
comprising three mutually perpendicular legs with two of the
mutually perpendicular legs having a slightly smaller rectangular
tubular shape with the same general cross-sectional configuration
as said cross member and the third mutually perpendicular leg
having a slightly smaller size with the same general
cross-sectional configuration as said vertical post member; and
said plurality of elongated structural support members and said
corner ties being assembled so as to form a generally rectangular
parallelepiped framework.
3. A metal-enclosed switchgear framework as claimed in claim 1
wherein:
each of said plurality of elongated structural support members
comprises a generally U-shaped tubular member including a plurality
of sidewalls and having a longitudinally extending opening at one
of the corners between the adjacent sidewalls with outwardly facing
flanges formed at each edge of the longitudinal opening and
extending longitudinally of said structural support member; and
each of said corner ties comprising three mutually perpendicular
leg portions, each having a longitudinal opening with outwardly
facing flanges formed at the edges of the opening and extending
along the leg portion and wherein the outwardly facing flanges of
each of said corner ties does not extend beyond the outer edge of
the outwardly facing flanges formed on said plurality of structural
support members.
4. A metal-enclosed switchgear framework as claimed in claim 3,
wherein:
the flanged portions of said elongated structural support members
have a plurality of openings formed adjacent to the opposite ends
thereof;
the flanged portions of said corner ties have an elongated slotted
opening formed therein so that when a leg portion of said corner
tie is disposed in the longitudinal opening extending through said
structural support member, at least a portion of the holes formed
in the flanged portion of said structural support member are
substantially aligned with the slot formed in the leg portion of
said corner tie member; and a plurality of fasteners are disposed
to connect the flanged portions of said corner tie to the flanged
portions of said structural support member.
5. A metal-enclosed switchgear framework as claimed in claim 3
wherein each leg of said corner tie has substantially the same
shape as the associated structural support member within which the
leg portion of said corner tie is disposed.
Description
BACKGROUND OF THE INVENTION
This invention relates to a corner tie of a type particularly
adapted for use on metal enclosed switchgear suitable for
relatively low voltage power distribution service. More
specifically, this invention relates to a one-piece corner tie
suitable for holding three switchgear structural members in
predetermined positions.
A metal enclosed switchgear installation usually includes one or
more units with each unit consisting of a plurality of sections or
cells. The sections are assembled side-by-side to provide a unit or
switchgear assembly capable of housing a desired number of circuit
breakers or other circuit controlling devices. The maximum number
of sections assembled in a unit at the factory is usually
determined by the handling and shipping facilities available.
Each switchgear unit comprises a structural framework in a formed
sheet metal enclosure. The structural framework must support the
considerable weight of conductors and circuit interrupting devices
mounted in the switchgear section. The structural framework
normally consists of elongated structural members tied or secured
together in a generally perpendicular relationship at corner
points. A structural member particularly adapted for use in
switchgear construction is shown in U.S. Pat. No. 2,167,525 issued
July 25, 1939 to R. W. Rosendale. A two piece corner assembly for
connecting two or more of this type structural members is shown in
U.S. Pat. No. 3,353,854 issued Nov. 21, 1967 to K. M. Hansen. Each
of the elongated structural members essentially comprises a
generally rectangular tubular member having an open portion in
place of one of the longitudinal extending corners, with both edges
of the open portion formed into two perpendicular outwardly
extending longitudinal flange portions. These structural members
are normally connected in a mutual perpendicular alignment with the
open portion of each switchgear structural member facing the inside
of the switchgear unit. The flange portions thus form recessed
surfaces around the opening into the switchgear unit. Formed sheet
metal covers having inward facing lip portions can be mounted to
these flange portions to provide a flush outer surface.
The switchgear structural members must be tied or secured together
at intersecting or meeting corners. It is necessary that where
three corner structural members are connected they be held securely
in mutually perpendicular alignment. It is desirable that the
corner tie be of a simple economic construction and provide a
strong and pleasing looking corner with no visible openings. It is
also desirable to have a corner tie which can connect, support and
align the mutually perpendicular structural members without the use
of fastening means or apparatus, until the entire switchgear unit
framework is assembled.
SUMMARY OF THE INVENTION
In accordance with the invention, a metal enclosed switchgear unit
is provided with main through horizontal bus and vertical section
bus conductors or risers having circuit interrupting devices
mounted thereto. The circuit breakers are mounted close to the
vertical section bus and are recessed from the front of the
switchgear section. Formed sheet metal covers are mounted on the
sides, back and top of the switchgear unit. Well or pan-shaped
covers are mounted at the front of the switchgear unit, and cover
the individual circuit interrupting devices. The outer edges of the
well-shaped covers are flush with the front of the switchgear unit
and the inner surface is approximately flush with the front of the
circuit interrupting devices. A cut out is made in the flat inner
surface of the well-shaped cover for the circuit breaker operating
handle to pass therethrough.
Circuit interrupters, bus conductors and covers are mounted on the
main switchgear structural members. The main switchgear structural
members comprise generally rectangular members each including a
plurality of sidewalls with the sidewalls being spaced from one
another at one of the corners to form a longitudinally extending
opening and having perpendicular outwardly facing flanges formed at
the longitudinally extending opening. A pair of perpendicular
flanges extend along the longitudinal axis of the structural member
and have mounting holes formed therein. The structural members come
together and are held securely in a mutually perpendicular
relationship at each corner of the switchgear unit by a one-piece
corner tie. Eight corner ties are required for each switchgear
unit.
Although the switchgear structure described comprises mutually
perpendicular members, it is to be understood that the teachings of
the present invention can be applied to structural members
positioned in other predetermined locations or orientations. The
corner tie comprises three mutually perpendicular legs each of
which fits inside a portion of the associated structural members
which come together at the corner of the switchgear unit. The
vertical structural member is of a generally square tubular
construction which includes a plurality of sidewalls with the
sidewalls at one corner being spaced from one another to form a
longitudinally extending opening between the edges of said
sidewalls. Outwardly extending flange portions are formed at the
edges of the opening in the vertical structural member. The
vertical leg of the switchgear corner tie over which the vertical
structural member fits is of the same general cross sectional
configuration, but of a generally smaller size so as to fit inside
a portion of the vertical structural member. Slots are formed in
the flange portions of the vertical leg of the corner tie to
facilitate fastening to preformed holes in the flange portions of
the vertical structural member.
The front-to-back and side-to-side structural cross members are of
a generally rectangular tubular construction with an opening, in
place of one of the longitudinal corners of the structural members,
formed thereon. Outwardly extending flanged portions are formed
longitudinally along the edges of the opening in the front-to-back
and the side-to-side structural cross members. All horizontal
structural cross members have the same cross-sectional
configuration. The corner tie member has two horizontal generally
perpendicular extending legs to which the vertical leg, extending
perpendicular to horizontal legs, is secured or attached. Each of
the horizontal legs of the corner tie is of the same general
configuration or shape as the horizontal structural cross members,
but of a slightly smaller size, so as to fit internally of a
portion of the horizontal structural members. Elongated slots are
formed in the flanged portions of the horizontal legs of the corner
tie member to facilitate attachment or fastening to the associated
horizontal structural members. The corner tie is of a one-piece or
unitary construction and fits inside the end portion of each of the
structural members which are brought together or assembled to form
a corner of the switchgear section.
A three legged corner tie has six flanged portions. Each flanged
portion of the corner tie extends from a side of the rectangular or
square legs which the tie member includes. The depth of the side
from which each of these flanged portions extends can be slightly
greater than the depth of the side of the associated structural
member with which it is flush side so that when the corner tie is
secured to the structural members and the flanged members of the
corner tie are pulled into engagement with the flanged portion of
the structural member, the legs of the corner tie give slightly and
a slightly resilient or lockwash washer effect between the corner
tie and the structural support member is obtained or results. The
corner tie fits inside three structural members brought together at
each corner, and any slight separation or misalignment between the
structural members during assembly is closed by the corner tie
member. That is, if the end of the horizontal structural member
does not align perfectly with the vertical structural member and a
slight opening is left therebetween, a portion of the corner tie
member is in position behind the structural members to close this
opening. This helps provide an essentially dead front construction
with no openings through the framework into the body or interior of
the switchgear unit.
The disclosed corner ties provide a simple one-piece construction
which facilitates assembly of the switchgear unit. The corner tie
positions the horizontal cross members and the vertical corner
posts during assembly, and supports these parts of the framework
during assembly without the use of mounting hardware. After the
switchgear structural framework is assembled, mounting hardware can
be used to securely fasten the corner tie members to the horizontal
and vertical structural members. The flange portions of the corner
tie members are provided with slotted openings therein so that a
plurality of bolts or self-tapping screws can secure each flange
portion of the corner tie to the associated flange portion of the
structural support members. The corner tie member provides for a
structurally strong corner and a totally stable switchboard
framework construction.
The slotted openings in the corner tie flange portions and the
location of the corner tie behind any openings between structural
members allows easy assembly of the structural framework without
exact positioning of the structural members. Slight misalignment or
positioning of the structural members are compensated for by the
corner tie construction and do not affect the appearance or
strength of the switchboard framework.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention, reference may be had
to the preferred embodiment exemplary of the invention shown in the
accompanying drawings, in which:
FIG. 1 is a perspective view of a double-section switchgear unit
utilizing the teachings of the present invention;
FIG. 2 is a perspective view of a portion of the switchgear unit
shown in FIG. 1, showing the corner tie member in place;
FIG. 3 is an exploded perspective view of the corner tie and
structural member shown in FIG. 2;
FIG. 4 is a top view of the vertical legs of the corner tie member
shown in FIG. 3;
FIG. 5 is a bottom view of the vertical legs shown in FIG. 4;
FIG. 6 is a top view of the horizontal legs of the corner tie;
and
FIG. 7 is a side view of that portion of the corner tie shown in
FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and to FIG. 1 in particular, there
is shown a switchgear unit 10 comprising two generally rectangular
upstanding sections or cells 12 disposed in side-by-side
relationship. Additional sections 12 may be added as desired.
Generally, each switchgear unit 10 comprises a plurality of
vertical structural members 16 and horizontal structural cross
members 18 which are assembled to form the main switchgear
framework. Formed cover sheets 20 are added to the top back and
sides of the framework to partially enclose the switchgear unit 10.
The front portion of each switchgear 12 is vertically divided into
a plurality of small enclosures 22 for various circuit breakers and
circuit controlling apparatus. These enclosures 22 are vertically
stacked or disposed one above the other up to the height of the
switchboard section 12. As can be seen in FIG. 1, when molded case
circuit breakers are mounted in the switchgear section 12, the
front of the circuit breaker is set back or spaced from the front
of the switchgear section 12. Circuit breaker operating handles 26
of the molded case circuit breakers are also recessed or spaced
from the front of the switchgear section 12. Covers, which are
attached to the front of the switchboard section 12, form a part of
the front face of switchgear unit 10. Circuit breaker operating
handles 26 project through openings formed in front covers. As just
mentioned, the breakers handles 26 are set back from the front of
switchboard unit 10 and are partially protected from material or
personnel moving across or in front of the switchboard unit 10.
The main frame of the switchgear unit 10 is constructed from
vertical corner posts or structural members 16 and cross members or
horizontal structural members 18 which are connected together at
each corner of the switchgear unit 10. A corner tie member 30
connects vertical post 16 to two cross members at each corner of
the switchgear unit 10. Eight corner ties 30 are required for each
switchgear unit 10.
Referring now to FIG. 2, there is shown a more detailed view of tie
member 30 with the vertical corner post 16 and the cross members 18
in place. Vertical corner post 16 is formed as a generally square
or rectangular member having a plurality of sidewalls with the
sidewalls being spaced from one another at one corner to form a
longitudinally extending opening between the edges of the adjacent
sidewalls. The outwardly extending flange portions 32 of structural
member 16 project perpendicularly away from the edges of the
sidewalls at the opening thus formed. The flange portions 32 extend
longitudinally along the vertical corner post 16. The flange
portions 32 extend almost the length of the vertical corner post 16
but terminate a short distance from both ends of vertical post 16.
A two-sided angle portion 15 of the vertical post 16 extends beyond
the ends of flange portions 32. Vertical post 16 is fit onto corner
tie 30 so that the end 17 of vertical post 16 is approximately
flush with the bottom 19 (FIG. 7) of the corner tie 30. Vertical
corner post 16 has a plurality of openings 34 formed at the ends of
flange 32 to facilitate attachment or fastening to corner tie
30.
Cross members 18 are of a generally rectangular tubular
construction with a portion which would contain one of the corners
being open, with outward facing flanges 36 formed at the opening.
Flanges 36 run or extend parallel to the longitudinal axis of cross
members 18 for approximately the entire length. Openings 34 are
formed near the end of flanges 36 to facilitate attachment to tie
member 30. A portion of cross member 18 is fit onto corner tie 30
so that the end 37 of cross member 18 is flush with the edge of the
angle portion 15 of vertical corner post 16.
Corner tie member 30 has three mutually perpendicular legs 40, 42
and 44. Vertical leg 40 has the same general cross-sectional
configuration or shape as vertical corner post 16 but with suitable
dimensions so that corner post 16 can slide easily over vertical
leg 40, as can best be seen in FIG. 2. Horizontal legs 42 and 44
are formed from one piece, as shown in FIGS. 6 and 7, and are
perpendicular to each other and to vertical leg 40. Horizontal legs
42 and 44 are of the same general cross-sectional shape as cross
members 18, but of a somewhat smaller size so that a portion of
cross members 18 can fit easily over legs 42 and 44, as shown in
FIG. 2. Vertical leg 40 is welded or otherwise permanently attached
to horizontal legs 42 and 44 in a mutually perpendicular
relationship. Flanges 46 are formed at the edges of the openings of
legs 40, 42 and 44 of corner ties 30. Elongated slotted openings 48
are formed in flanges 46. As shown in FIG. 2, a plurality of
openings 34 formed in vertical corner post 16 and cross members 18
are easily accessible through the slots 48 in corner tie 30. More
than one fastener can pass through each slot 48 to securely hold
structural members 16 and 18 in proper alignment. The portions of
vertical corner post 16 and cross members 18 which slide onto
corner tie 30 are securely fastened to corner tie 30. The
three-legged corner tie 30 is of a one-piece or unitary
construction and helps to properly position the structural members
16 and 18 of the switchgear framework. Each cross member 18 and
corner post 16 will slide over one of the legs 40, 42 or 44 of the
corner tie 30 and when in proper position can be bolted to the
corner tie 30. The entire structural framework can be constructed
or assembled before fastening structural members 16 and 18 to
corner tie 30, since the corner tie 30 construction will position
and hold structural members 16 and 18 until bolted in position.
Alternately, structural member 16 or 18 can be secured to corner
tie 30 as soon as they are into slide position. Bolts or
self-tapping screws can be used to fasten to flanges 46 of corner
tie 30 to the flanges 32 or 36 of structural members 16 or 18,
respectively. After assembly, the corner ties 30 cannot be seen
from externally of the switchgear unit 10. If there is any slight
opening left between the ends of structural member 18 and the
angle-shaped portion 15 of structural member 16, it will be closed
by a portion of corner tie 30.
In one embodiment of the invention, the sides 41 of corner tie 30
to which flanges 46 are attached can be made slightly longer or
larger in size than the corresponding side of corner post 16 or
cross members 18 so that when corner post 16 and cross members 18
are positioned on corner tie 30, flanged portions 46 are slightly
separated from openings 34. Thus, when corner tie 30 is fastened to
structural member 16 or 18, there must be some slight deformation
of the part 30 and this will keep some pressure on the fastening
devices to help assure that the fasteners do not work loose during
shipping or use of the switchgear unit 10.
Using the one-piece corner tie 30, assembly of the switchgear 10
framework is relatively simple. The corner tie 30 assures that
structural members 16 and 18 are in proper mutually perpendicular
alignment and the slotted flanges 46 allow the corner to be formed
without extreme accuracy which would be required to line up to
prepunched holes. A plurality of fasteners can be used in each slot
48 to securely hold corner tie 30 to structural members 16 and 18.
The one-piece corner tie 30 supports the framework and facilitates
assembly. Corner tie 30 also provides a structurally strong corner
and a totally stable framework construction.
* * * * *