U.S. patent number 3,917,374 [Application Number 05/498,723] was granted by the patent office on 1975-11-04 for electric connector apparatus.
This patent grant is currently assigned to Kearney-National Inc.. Invention is credited to Robert E. Murdock.
United States Patent |
3,917,374 |
Murdock |
November 4, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
Electric connector apparatus
Abstract
An electric terminal such as a transformer bushing having a
contact socket of conducting material is provided with a quench
tube arranged in aligned substantially coaxial relation with the
contact socket and constructed of an inner sleeve of arc
extinguishing material and an outer sleeve of mechanically strong
plastic material. Peripheral grooves are formed about the inner
surface of the quench tube and resilient grommets are disposed in
the grooves. An associated connector which may be of the elbow type
is provided with a contact pin which includes a tubular element of
conducting material to the end of which a stem of mechanically
strong plastic material is affixed to support a hollow sleeve
disposed thereabout and formed of arc extinguishing material and
which is bevelled at its outer end to facilitate entry of the
contact pin into and through the quench tube and into the contact
socket so as to form a connection between the contact socket and
the tubular element of conducting material.
Inventors: |
Murdock; Robert E. (Stone
Mountain, GA) |
Assignee: |
Kearney-National Inc. (Atlanta,
GA)
|
Family
ID: |
23982238 |
Appl.
No.: |
05/498,723 |
Filed: |
August 19, 1975 |
Current U.S.
Class: |
439/184; 439/586;
439/607.04 |
Current CPC
Class: |
H01R
13/53 (20130101); H01F 27/04 (20130101); H01H
33/77 (20130101) |
Current International
Class: |
H01F
27/02 (20060101); H01H 33/77 (20060101); H01F
27/04 (20060101); H01R 13/53 (20060101); H01H
33/70 (20060101); H01R 013/52 () |
Field of
Search: |
;339/111,143R,59R,6R,61R,94R,272R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Lake; Roy
Assistant Examiner: Jones; DeWalden W.
Attorney, Agent or Firm: Rodgers; Walter M.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. Electric connector apparatus comprising a tubular contact pin, a
tubular contact socket of conducting material having at least one
open end arranged to cooperate with said contact pin, and a hollow
tubular quench tube disposed at said one end of said contact socket
and arranged in substantially aligned coaxial relation therewith so
as to accommodate telescopic movement of said contact pin relative
to said contact socket and quench tube, said tube being of
composite construction and including an inner sleeve of arc
extinguishing insulating material and an outer sleeve of
mechanically strong plastic material.
2. Apparatus according to claim 1 wherein said outer sleeve
includes an outer end portion at the end thereof remote from said
contact socket which completely overlies the outer end of said
inner sleeve so as to prevent said contact pin from colliding
therewith.
3. Apparatus according to claim 1 wherein said inner sleeve
includes an inner end portion adjacent said one end of said contact
socket which protrudes inwardly beyond the inner end of said outer
sleeve so as to shield said outer tube from contact with an
electric arc drawn between said contact pin and said contact
socket.
4. Apparatus according to claim 1 wherein at least one groove is
formed about the inner periphery of said quench tube and wherein a
resilient grommet is seated within said groove for guiding said
contact pin and for sealing said tube.
5. Apparatus according to claim 4 wherein said groove is disposed
at the junction between the outer end of said inner sleeve and the
adjacent part of said outer end portion of said outer sleeve.
6. Apparatus according to claim 1 wherein a plurality of axially
spaced grooves are formed about the inner periphery of said quench
tube and wherein a plurality of resilient grommets are sealed
within said grooves respectively, the inner peripheries of said
grommets being configured to accommodate axial movement of said pin
through said tube.
7. Apparatus according to claim 2 wherein said contact socket and
said quench tube are disposed within a hollow support at least a
portion of which is internally threaded to cooperate with external
threads on said outer sleeve and wherein a pair of tightening
recesses are formed in said outer end portion of said outer sleeve
for receiving cooperating parts of a tool whereby said quench tube
is threadedly related with said hollow support.
8. A quench tube constituting a component of an electric connector
apparatus, said quench tube comprising an inner sleeve of arc
extinguishing material, and an outer sleeve of mechanically strong
plastic material, said outer sleeve including an end portion at one
end which completely overlies the associated end portion of said
inner sleeve and said inner sleeve protruding beyond the other end
of said outer sleeve.
9. A quench tube according to claim 8 wherein at least one groove
is formed about the inner periphery of said quench tube and
disposed at the junction between said end portion of said outer
sleeve and the associated end of said inner sleeve and wherein a
resilient grommet is seated within said groove.
10. A quench tube according to claim 8 wherein a plurality of
grooves are formed about the inner periphery of said quench tube
and wherein a plurality of resilient grommets are seated within
said grooves respectively.
11. A contact pin constituting a component of an electric connector
apparatus, said contact pin comprising a tubular pin of conducting
material, a stem of mechanically strong plastic material having a
cap portion at one end and secured at its other end to the end of
said tubular pin which is subjected to arcing and arranged in
coaxial relation therewith, and a hollow tubular sleeve of arc
extinguishing material of considerably less mechanical strength
than said stem and disposed about said stem and in coaxial relation
therewith and having one end in snug engagement with said cap
portion of said stem and having the other end in snug engagement
with the adjacent end of said tubular pin of conducting
material.
12. A contact pin according to claim 11 wherein said cap portion of
said stem is bevelled at the part thereof remote from said hollow
sleeve of arc extinguishing material.
Description
Quench tubes for use in connection with electric terminal bushings
are formed of arc extinguishing material which is extremely
proficient in extinguishing electric arcs. In like fashion the nose
portion of known contact pins which cooperate with known quench
tubes associated with electric bushings are also formed of highly
efficient arc extinguishing material. Difficulties encountered in
connection with elements formed of certain arc extinguishing
materials are usually due to the mechanical brittleness of the arc
extinguishing material. Since connector apparatus is frequently
subjected to heavy duty rough usage, elements formed of highly
proficient arc extinguishing materials frequently are chipped or
broken and hence rendered useless under many service
conditions.
Plastic materials are known which are very strong mechanically and
which are well adapted to withstand a high degree of mechanical
stress. Unfortunately such strong materials are not well suited for
use as arc extinguishing materials.
According to the present invention, advantage is taken of the
highly proficient arc extinguishing characteristics of known arc
extinguishing materials and also of known mechanically strong
plastic materials and such materials are combined in such a way
that compensation for the brittle characteristics of known
proficient arc extinguishing materials is achieved by use of a
mechanically strong plastic material which is not required to
perform an arc extinguishing function. More specifically a quench
tube is formed according to this invention and comprises an inner
sleeve of arc extinguishing material and an outer sleeve of
mechanically strong plastic material. The outer or entry end of the
quench tube is constructed so that the strong outer plastic
material completely overlies the outer end of the inner sleeve
while the inner sleeve is arranged to protrude inwardly beyond the
inner end of the outer sleeve. Thus by this construction the inner
sleeve is mechanically protected from collision with the contact
pin and the inner end of the outer sleeve is shielded from the
deleterious effects of arcing. In addition at least one peripheral
groove is formed about the inner surface of the quench tube and a
grommet formed of resilient material is seated within the groove to
guide the contact pin through the quench tube and to seal the tube
against undesired expulsion of highly ionized products of arcing.
Preferably at least two parallel peripheral grooves are formed
about the inner surface of the quench tube and associated resilient
grommets are disposed therein so as effectively to guide and align
the associated contact pin during circuit opening and closing
operations. According to another feature of the invention the inner
end of the contact pin is provided with a contact stem which is
coaxially disposed with respect to the conducting part of the
contact pin and is formed of mechanically strong plastic material
and an outer sleeve of arc extinguishing material is disposed about
the inner stem and its inner end is bevelled to facilitate entry
into the quench tube 14. According to another modification of the
invention, the end of the stem remote from the conducting part of
the contact pin is provided with a cap for holding the sleeve of
arc extinguishing material securely in place and the extreme outer
end of the cap preferably is bevelled to aid in aligning the
contact pin structure with the resilient grommets.
For a better understanding of the invention reference may be had to
the following detailed description taken in conjunction with the
accompanying drawings in which
FIG. 1 is a view partially in section of a bushing connector and
associated quench tube together with an elbow type connector with
the parts shown in an open circuit position for clarity;
FIG. 2 is a top view of a quench tube constructed according to this
invention;
FIG. 3 is a cross-sectional view taken along the line designated
3--3 in FIG. 2;
FIG. 4 is a perspective view of a contact pin constructed according
to one form of the invention;
FIG. 5 is a view partially in section taken along the line
designated 5--5 in FIG. 4;
FIG. 6 is a perspective view of a contact pin formed according to
another form of the invention and in which;
FIG. 7 is a view partially in section and taken along the line
designated 7--7 in FIG. 6.
With reference to FIG. 1, the numeral 1 generally designates an
elbow connector of conventional construction while the numeral 2
generally designates a bushing connector of more or less
conventional construction and which cooperates with the elbow
connector 1 to form a connection between an outside conductor such
as is designated by the numeral 3 and electric apparatus which may
constitute a transformer winding, one terminal of which is
designated by the numeral 4, the bushing 2 being mounted within an
aperture formed in the transformer casing (not shown) and supported
therein by suitable known support ring 5.
The elbow connector 1 comprises a contact pin having a rod-like or
tubular conducting part 6 and a coaxially arranged part 7 formed of
arc extinguishing material both of which are cylindrically
configured together with insulating housing structure 8 about which
is disposed elastomeric conducting material 9. A hook 10 is
arranged to receive an end of a clamp stick by which the connector
1 is manipulated.
The bushing connector 2 comprises a contact socket 11 the upper end
12 of which is open. Slots 13 are formed in the sides of contact
socket 11 to render the upper end of the contact socket expandable
for receiving the contact pin 6, 7.
The quench tube 14 is provided with exterior threads 15 which
cooperate with internal threads formed within the support structure
comprising inner metallic conductive sleeve 16 which is received
within a cavity formed within insulating housing support 17.
Insulating housing support 17 is provided with elastomeric
conducting material 18 which is grounded to bracket 5 and in turn
to the tank of the associated apparatus such as a transformer.
In order to complete a circuit between conductors 3 and 4, the
elbow connector 1 is manipulated in such a manner as to cause the
skirt 8 to envelope the housing support structure 17 and so as to
cause the arc extinguishing part 7 to pass through the quench tube
14 and downwardly into the contact socket 11. Of course when the
lower end 6a of the conducting tube 6 enters the open end of
contact socket 11 and engages the contact fingers defined by slits
13, the circuit is complete.
When the connector 1 is withdrawn, an arc is established between
the end portion 6a of conducting portion 6 of the contact pin as
the lower end 6a clears the upper end 12 of the contact socket 11.
The arc is extinguished by arc extinguishing portion 7 of the
contact pin and by the quench tube 14.
The quench tube 14 is formed according to one aspect of this
invention and comprises an inner sleeve 19 and an outer sleeve 20.
Inner sleeve 19 is constructed of arc extinguishing material which
is very effective in extinguishing electric arcs. Outer sleeve 20
is constructed of mechanically strong plastic material. The outer
sleeve is provided with an outer end portion 21 which completely
overlies the outer end portion 22 of the inner sleeve 19. From FIG.
3, it is apparent that the outer end 22 of the inner sleeve 19 is
completely protected from inadvertent collision with the end 7a of
the contact pin. Since the inner end 23 of the inner sleeve 19
protrudes inwardly beyond the inner end 24 of the outer sleeve 20,
it is apparent that the outer sleeve 24 is completely shielded from
contact with electric arcs which are formed between the end 6a of
conducting tubular pin 6 and the upper end 12 of the contact socket
11.
For the purpose of efficiently aligning and guiding movement of the
contact pin 6,7 through the quench tube 14 and for sealing these
parts against the expulsion of products of an arcing operation, at
least one groove is formed about the inner periphery of the quench
tube 14 and a grommet formed of resilient material is seated within
such groove. Preferably a pair of grooves and their associated
resilient grommets commonly called O-rings are employed as shown in
FIG. 3. One groove and its associated resilient grommet are
collectively designated in FIG. 3 by the numeral 25 while the other
groove and its associated grommet are designated by the single
numeral 26. Preferably, one groove and associated O-ring 25 should
be disposed at the junction between the outer end 22 of the inner
sleeve 19 and the end portion 21 of the outer sleeve 20.
For the purpose of facilitating a snug assembly of the quench tube
14 within the upper end of the sleeve 16 disposed within the
housing support structure 17, a pair of recesses designated by the
numerals 27 and 28 are formed in the upper end portion 21 of the
outer sleeve 20. Thus a tightening tool not shown but having a pair
of projections is arranged with the projections inserted into the
recesses 27 and 28 and then rotated to tighten or loosen the
threads 15 and their associated threads formed within the structure
16,17.
The contact pin shown in FIGS. 4 and 5 is constructed according to
one aspect of the invention and comprises a tubular conducting part
6 to the inner end 6a of which is secured a stem 7b formed of
mechanically strong plastic material. The stem 7b is firmly secured
within a recess 6b formed within the conducting part 6 of the
contact pin. This securement may be by means of threads, adhesive
or by any other suitable means. Disposed about the stem 7b is a
sleeve 7c formed of arc extinguishing material. Since arc
extinguishing material is mechanically brittle, and because the
stem 7b is mechanically strong but formed of material which is not
particularly effective as an arc extinguishing material, the result
is a mechanically strong highly effective arc extinguishing
structure. According to one aspect of the invention, the inner end
of sleeve 7c is bevelled as indicated at 7d to facilitate entry of
part 7 into quench tube 14 and in contact socket 11. The threaded
end 6c of conducting tubular structure 6 is threaded into a
suitable conductor such as a contact block as disclosed and claimed
in U.S. Pat. No. 3,768,065 granted Oct. 23, 1973. The aperture 6d
in conductive pin 6 is simply for the purpose of receiving a part
of a tightening tool whereby the contact pin is screwed into the
contact block.
A contact pin constructed according to another aspect of the
invention and as shown in FIGS. 6 and 7 is similar to the
arrangements of FIGS. 4 and 5 except that the inner end of the stem
is provided with a cap designated by the numeral 7e which is
bevelled as indicated at 7f, the cap 7e being integral with the
stem 7g. Of course the stem and cap are formed of strong plastic
material and the inner end is secured to the conducting tube 6 by
adhesive or by any other suitable means. The outer sleeve 7h is
formed of arc extinguishing material. One advantage afforded by the
structure of FIGS. 6 and 7 is attributable to the cap 7e which is
of mechanically strong plastic material and which therefore shields
the end 7i of sleeve 7h from collision with the outer end of the
quench tube.
From the above description, it is apparent that by the invention
both the contact pin and the quench tube are constructed in such
manner as to take advantage of the arc extinguishing properties of
the brittle sleeves such as 7c, 7h and 19 and advantage is also
taken of the strong mechanical properties of the plastic stems such
as 7b and 7g and of the protective outer sleeve 20. In addition,
the resilient grommets or O-rings and their associated grooves
designated 25 and 26 serve to align and guide the contact pin into
efficient sliding telescopic relation with respect to the quench
tube 14 and the contact socket 11 while simultaneously sealing the
structure against undesired escape of gases through the upper end
of the quench tube 14. If such gases were to escape and be driven
by the structure 8 of the elbow connector 1 downwardly into contact
with the transformer tank, such action might result in a short
circuit of the conductive elements of the transformer to ground by
establishing a conductive path upwardly through the bushing 2 and
then downwardly around the outside thereof and into contact with
the grounded tank. Furthermore, since the O-rings and the contact
pin 6,7 seal the upper end of quench tube 14, pressure in the
region of the arc is elevated during the initial portions of an
interrupting operation and such increased pressure tends to
facilitate extinguishment of the arc. Furthermore since the
tightening recesses 27 and 28 are formed in the mechanically strong
outer end portion 21 of the outer sleeve 20, it is possible to
effect a tight and snug fit between the threaded portion 15 of the
quench tube 14 and the associated internal threads of sleeve 16
without imposing deleterious mechanical stresses on the brittle
tube 23.
* * * * *