VACUUM SWITCHING APPARATUS AND
CONTACT ASSE LY THEREFOR
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority from and claims the benefit of L .
Patent Application Serial No. / , , filed September 4, 2013, winch i
incorporated by reference herein.
BACKGROUND
Field
The disclosed concept relates to vacuum switching apparatus and, in
particular, vacuum switching apparatus such as, fo example, vacuum interrupters.
The disclosed concept also pertains to contact assemblies for vacuum interrupters.
Circuit breakers such as, for example, power circuit breakers for
systems operating above about 1,000 volts, typically employ vacuum mterrapters as
the switching devices. Vacuum interrupters generally include separable electrical
contacts disposed within an insulating housing. Typically, one of the contacts is fixed
relative to both the housing and to an external electrical conductor, which is
electrically interconnected with power circuit associated with the vacuum
interrupter. The other contact is part of movable contact assembly including a stem
of circular cross-section and a contact disposed o one end of the stem and enclosed
within a vacuum chamber. A driving mechanism is disposed on the other end,
external to the vacuum chamber.
The contacts are subjected to significant contact forces, which for
example, are associated with relatively high electrical currents. Thus, among other
issues, the contacts are susceptible to breaking or bending.
There is, therefore, room for improvement in vacuum switching
apparatus, such as vacuum interrupters, and in contact assemblies therefor
SUMMARY
These needs and others are met by embodiments of the disclosed
concept which are directed to reinforced contact assemblies for vacuum switching
apparatus, such as vacuum interrupters.
As one aspect of the disclosed concept, a contact assembly is provided
for a vacuum switching apparatus. The contact assembly comprises: a contact
member: and a reinforcing member adapted to structurally reinforce the contact
member.
The contact member may comprise a first side, a second side disposed
opposite the first side, and a coniact thickness measured by the distance between the
first side and the second side. The reinforcing member may have reinforcement
thickness, wherein the reinforcement thickness is less than the contact thickness. The
contact member may further comprise a contact diameter, and the reinforcing member
may comprise a reinforcement diameter, wherein the re fo rcemen diameter is ess
tha the contact diameter.
The reinforcing member may be embedded within the contact member
between the first side of the contact member and the second side of the contact
member. Alternatively, the reinforcing member may be adhered to a corresponding
one of the first side of the coniact member and the second side of the contact member.
The contact member may be made from a first material, and the
reinforcing member may be made from a second material . wherein the first material is
different from the second materia!. The first material may have a first coefficient of
thermal expansion and the second material may have a second coefficient of thermal
expansion. The first coefficient of thermal expansion may be substantially the same
as the second coefficient of thermal expansion.
In accordance with another aspect of the disclosed concept a vacuum
switching apparatus comprises: a vacuum envelope; and at least one contact assembly
enclosed within the vacuum envelope and comprising: a contact member, and a
reinforcing member adapted to structurally reinforce the contact member.
The vacuum switching apparatus may be a vacuum interrupter. The
coniact assembly may include a fixed contact assembly and a movable contact
assembly. The movable contact assembly ma be movable between a closed position
i electrical contact with the fixed contact assembly and an open position spaced apart
from the fixed contact assembly.
BRIEF PESC PTIO OF THE DRAWINGS
A fo i understanding of the disclosed concept ca b gained from the
following description of the preferred embodimetits when read in conjtmction with the
accompanying drawings in which:
Figure 1 is a side elevation partially in section view of vacuum
interrupter and contact assembly therefor in accordance w h an embodiment of the
disclosed concept;
Figure 2 i an enlarged section view of the contact assembly of Figure
1;
Figure 3A i an isometric partially in section view of a contact
assembly n accordance with another embodiment of the disclosed concept;
Figure 3B is a section view taken along line 3B-3B of Figure 3A;
Figure 4A is an exploded isometric view of contact assembly in
accordance w th a further embodiment of the disclosed concept, also showing the
contact reinforcement assembled in partially hidden and phantom line drawing;
Figure 4B is a section view take along line 4B- B of Figure 4A;
Figure 5 i an exploded isometric view of a contact assembly in
accordance with another embodiment of the disclosed concept;
Figure 6 is an isometric view of a contact assembly i accordance with
a further embodiment of the disclosed concept; and
Figure 7 is an isometric view of a contact assembly in accordance with
another embodiment of the disclosed concept.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The disclosed concept is described in association with vacuum
interrupters, although the disclosed concept is applicable to a wide range of contact
assemblies for use with other vacuum switching apparatus an electrical switching
apparatus.
Directional phrases used herein such as, for example, up, down and
deri vatives thereof relate to the orientation of the elements shown in the drawings and
are not limiting upon the claims unless expressly recited therein.
As employed herein, the statement that two or more parts are
"connected" or "coupled" together shall mean that the parts axe joined together either
directly or joined through one or more intermediate parts. Further, as employed
herein, he statement that two or more parts are "attached" shall mean that the parts
are joined together directly.
As employed herein, the ter "adhered" shall mean joined using any
known or suitable bonding method (e.g., without limitation, gluing; welding; brazing;
soldering; solid state sintering; liquid phase sintering; mechanical pressing; melted
material deposit; metallurgical bonding).
As employed herein, the term "embedded" shall mean enclosed withi
(i.e., encapsulated). For example and without limitation, the reinforcing member of
the contact assemb in accordance with the disclosed concept can be embedded
within a corresponding contact member using any known or suitable method (e.g.,
without limitation, induction molding).
As employed herein, the term. 'Vacuum envelope" means an envelope
employing a partial vacuum therein.
As employed herein, the term "structurally reinforce" shall mean to
intentionally add strength to, or mechanically strengthen, a component suc that the
structural integrity (e .g., without limitation, bending strength; resistance to bending or
breaking) of the component is improved.
As employed herein, th term "number" shall mean one or an integer
greater than one (i.e., a plurality).
Referring to Figure , a vacuum switching apparatus, such as a vacuum
interrupter 2, is shown. The vacuum interrupter 2 includes a vacuum envelope 4,
which is shown in section view n Figure i to show hidden structures. The vacuum
interrupter 2 employs contact assemblies 00, 00', in accordance with a non-limiting
embodiment of the disclosed concept. Specifically, a fixed contact assembly 100 is at
least partially withi the vacuum envelope 4, and is movable (e.g.. without limitation,
up and down in the direction of arrow 700, from the perspecti ve of Figure ) between
the closed position, shown, in electrical contact with the fixed contact assembly 00,
and an open position (not shown) spaced apart from the fixed contact assembly 0.
It wil be appreciated that, for ease of i ustration and economy o
disclosure, only the fixed contact assembl 00 will be described, in detail herein.
However, it w l b understood tha any number of contact assemblies employed by
the vacuum switching apparatus may he substantially identical, or alternatively may
be of different known or suitable constructions, or a combination thereof.
Continuing to refer to Figure , and also to Figure 2, each contact
assembly 0, in accordance with the disclosed concept, includes a contact member
2, and a reinforcing member 4, which is adapted to structurally reinforce the
contact member 2. Thus, among other benefits the strength or structural integrity
of the contact assembly 00. is improved. That is, the contact assembly 00 is
substantially less susceptible to beiidiiig or breaking in response to relatively high
contact forces associated, for example with relatively high electrical currents. In
addition to the foregoing, the disclosed reinforced contact assembly design also
permits the overall size (e.g., without limitation, thickness) of the contact assembly
00 to be reduced. This, in turn, can result in cost-savings, for example, because less
material is required for the contact assembly.
The contact assembly 0, ',200,300,400,500,600 of the disclosed
concept w l be further appreciated with reference to the following EXAMPLES,
which will now be described with reference to Figure 1-7. t will be appreciated that
the following EXAMPLES are provided solely for purposes of illustration, and are
not intended to limit the scope of the disclosed concept.
EXAMPLE 1
The contact member 2 may include a first side , a second side
108 disposed opposite the first side 6, and a contact thickness measured by the
distance between the first side 06 and the second side 8, as shown n Figure 2.
The reinforcing member 104 may have a . reinforcement thickness 2 , which is less
tha the contact thickness 0 . See also contact thickness 0 measured by the
distance between first and second sides 306,308 of contact member 302, and
reinforcement thickness 3 of reinforcma member 304, in Figure 4B.
EXAMPLE 2
The contact member 02 may have a contact diameter , and the
reinforcing member 04 may have a reinforcement diameter 1 . The reinforcement
diameter 6 ma e less than the contact diameter , as show in Figure 2.
The reinforcing member 104,204,604 maybe embedded within the
contact member 102,202,602, as shown n Figures 2, A and 3 , and 7, respectively.
Specifically, the reinforcing member 4 may be embedded between the first side 106
of the contact member 02 and the second side 1 8 of the contact member 102, as
best shown in the section vie of Fi ure 2.
EXAMPLE 4
The reinforcing member 104,204,304,404 of the contact assembly
100,200,300,400 may be a generally planar member
EXAMPLE 5
The reinforcing member 204,404 of the contact assembly 200,400 may
be a mesh member, as respectively shown in the non-limiting examples of Figures 3A
and 3B, and Figure 5
EXAMPLE 6
The reinforcing member (e.g., without limitation, 4,204,604 can be
embedded within the corresponding contact member (e.g., without limitation
2,202,602) using any known or suitable method or process such as or example and
without limitation, vacuum induction casting, insertion into a melt prior to cooling,
dipping and removing, or any other known or suitable embedding method or process.
EXAMPLE 7
The reinforcing member 304 may alternatively be suitably adhered to a
corresponding one of the first and second sides 306,308 of the contact member 302, as
shown in Figures 4A and 4B See also reinforcing member 404 (show in the
exploded orientation prior to being adhered to first side 406 of contact member 402)
of Figure 5, and reinforcing member 504 adhered to contact member 502 of Figure 6).
EXAMPLE 8
t will be appreciated that the reinforcing member (e.g. without
Limitation, 304,404,504) may be adhered to the contact member (e.g., without
limitation, 302,402,502) using any known or suitable adhering method or process
such as, for example and without limitation, solid state diffusion sinter bonding, liquid
phase sinter bonding, mechanically pressing, welding, brazing, soldering, or otherwise
forming a metallurgical bond between the reinforcing member (e.g., without
limitation, 304,404,504) and contact member (e.g., without limitation, 302 4 2 5 2).
EXAMPLE 9
The contact member 502 of the contact assembly 500 may be a spiral
contact having a number of radial segments 550,560,570,580 (four are shown in the
non-limiting example of Figure 6). The reinforcing member 504 may include a
number of reinforcing elements 572,582 for the radial segments 570,580 respectively.
It will be appreciated that such reinforcing elements (e.g.. without limitation, 572,582)
may be suitably adhered to or imbedded within the corresponding radial segments
(e.g., 570,580) of the spiral contact 502. See also spiral contact 602 of contact
assembly 600, wherein the spiral contact 602 includes, for example and without
limitation, three radial segments 650,660,670 and the reinforcing member 604
includes three corresponding rein forcing elements 652,662,672. Each reinforcing
element 652,662,672 s embedded within the corresponding one of the radial
segments 650,660,670, as partially shown in Figure 7.
EXAMPLE 10
The contact member 102,202,302,402,502,602 may be made from the
first material such as, for example and without limitation, copper. The reinforcing
member 04,204,304,404,504,604 may be made from any k own or suitable second
material, which is preferably different from the first material of the contact member
102,202,302,402,502,602. By way of example, and without limitation, the reinforcing
member 4,204,304 404 504 604 may be made from tungsten, titanium, carbonfiber,
stainless steel, o any other known or suitable material capable of withstanding
elevated temperatures and possessing the necessary material properties to contribute
to the strength of the contact assembly 100,200,300,400,500,600.
EXAMPLE 1i
Preferably, the first material has a first coefficient of thermal
expansion and the second material has a second coefficient of thermal expansion,
which is substantially the same. By matching the thermal coefficients of expansion of
the contact member 102,202,302,402,502,602 and the enforcing member
104,204,304,404,504,604, thermally related disadvantages- such as thermal expansion
at different rates, and associated issues can be minimized a d the integrity of the
contact assembly 100,200,300,400,500,600 can be improved.
Accordingly, d e disclosed vacuum switching apparatus 2 includes a
unique contact assembly 00,200,300,400,500,600 having a hybrid construction
including a contact member 2,2 2, 2,402,502.602 and a reinforcing member
104,204,304,404,504.604. which is suitably embedded or adhered thereto so as to
structurally reinforce the contact member 102,202,302,402.502.602. n this manner,
among other benefits, the disclosed contact assembly 00,200,300,400,500,600,
resists bending or breaking when subjected to relatively high operating forces, and
enables the overall size (see, for example and without limitation, contact thickness
1 and reinforcement thickness 12 of Figure 2; see also contact thickness 0 and
reinforcement thickness 312 of contact assembl 300 of Figure 4B) to be reduced,
thereby correspondingly reducing associated manufacturing and product costs.
While specific embodiments of the disclosed concept have been
described in detail, it w l be appreciated by those skilled in the art that various
modifi cations and alternatives to those details could be developed i light of the
overall teachings of the disclosure. Accordingly, the particular arrangements
disclosed are meant to be illustrative only and not limiting as to the scope of the
disclosed concept which is to be given the full breadth of the claims appended and
any an all equivalents thereo

Claim:
A contact assembly (100,200,300,400,500,600) for a vacuum
switching apparatus (2), said contact assembly (100,200,300,400,500,600)
comprising:
a contact member (102,202,302,402,502,602); and
a reinforcing member (104,204,304,404,504,604) adapted to
structurally reinforce said contact member ( 2,202.302.402,502,602)
2. The contact assembly ( 00,200) of claim I wherein said contact
member ( 2,302) comprises a first side (106,306), a second side ( 08,308) disposed
opposite the first side (106,306), and a contact thickness ( , ) measured by the
distance between the first side (106,306) and the seco d side (108,308); wherein said
reinforcing member (104,304) has a reinforcement thickness ( 2,3 2); and wherein
the reinforcement thickness ( .1 , 2) is less than th contact thickness ( i 10,310).
3 The contact assembly ( 0) of claim 2 wherein said contact member
(102) further comprises a contact diameter ( 14); wherein said reinforcing member
(104) comprises a reinforcement diameter ( ); and wherein the reinforcement
diameter ( 6) is less than the contact diameter ( ).
4. The contact assembl y (100 ) of claim 2 wherein said reinforcing
member (104) is embedded within said contact member (102) between the first side
(106) of said contact member (1 2) and the second side ( 8 ) of said contact member
(102).
5. The contact assembly (300) of claim 2 wherein said reinforcing
member (304) is adhered to a corresponding one of the first s de (306) of sai contact
member (302) and the second side (308) of said eontact member (302)
6. The contact assembly ( 00,200,300,400) of claim 2 wherein said
reinforcing member (104,204,304,404) comprises a generally planar member.
7. The contact assembly (200,400 ) of claim 6 wherein said reinforcing
member is a mesh member (204,404).
8. The contact assembly (500,600) of claim 2 wherein said contact
member is spiral contact (502,602); wherein sai spiral contact (502,602) includes a
number of radial segments (550,560,570,580,650,660,670); and wherein said
reinforcing member 504,604 includes a number of reinforcing elements
(572,582,652,662,672} for sai radial segments (550,560,570,580,650,660,670).
9. The contact assembiy (100,200,300,400,500,600) of claim 1 wherein
said contact member (102,202,302,402,502,602) i ade from a first material;
wherein said reinforcing member ( 104,204,304,404,504,604) is made from a second
material; and wherein the first material is different from the second material.
10. The contact assembly ( 100,200,300,400,500,600) of claim 9 wherein
the first materia] has a first coefficient of thermal expansion ; wherein the second
material has a second coefficient of thermal expansion; and wherein the first
coefficient of thermal expansion is substantially the same as the second coefficient of
thermal expansion.
1 . A vacuum switching apparatus (2) comprising;
a vacuum envelope (4); and
at least one contact assembiy (100,200,300,400,500,600) according to
any of claims 1-10, said at least one contact assembly (100,200,300,400,500,600)
being enclosed within said vacuum envelope (4).
. The vacuum switching apparatus (2) of claim wherein said vacuum
switching apparatus is a vacuum interrupter (2); wherein said at least one contact
assembiy is a fixed contact assembly (100) and a movable contact assembly (100');
and wherein said movable contact assembly (100') is movable between a closed
position in electrical contact with the fixed contact assembiy ( 00) and an open
position spaced apart from the fixed contact assembly ( 00)