U.S. patent number 3,720,904 [Application Number 05/112,646] was granted by the patent office on 1973-03-13 for self-actuating loadbreak connector.
This patent grant is currently assigned to AMP Incorporated. Invention is credited to Frederick Carl De Sio.
United States Patent |
3,720,904 |
De Sio |
March 13, 1973 |
SELF-ACTUATING LOADBREAK CONNECTOR
Abstract
A loadbreak connector having a male contact retractable to a
cocked position and positively actuated to an extended position for
positive engagement with an associated high voltage connector.
Trigger apparatus initially retains the contact in a retracted
position. The contact includes venting structure to dissipate and
cool arc generating gases evolved upon connection of the contact to
the high voltage connector.
Inventors: |
De Sio; Frederick Carl
(Harrisburg, PA) |
Assignee: |
AMP Incorporated (Harrisburg,
PA)
|
Family
ID: |
22345096 |
Appl.
No.: |
05/112,646 |
Filed: |
February 4, 1971 |
Current U.S.
Class: |
439/131; 439/183;
200/51.09; 439/296 |
Current CPC
Class: |
H01R
13/53 (20130101) |
Current International
Class: |
H01R
13/53 (20060101); H01r 013/52 (); H01r 013/54 ();
H01r 013/62 () |
Field of
Search: |
;339/111,75,45,46,34
;200/77,51.09,144 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
advertisement from Electrical World, Jan. 1, 1972, issue, pp. 64
& 65..
|
Primary Examiner: Champion; Marvin A.
Assistant Examiner: Lewis; Terrell P.
Claims
What is claimed is:
1. An electrical connector, comprising: a housing,
a conductive shield provided over the housing,
an electrical insulation layer provided over the shield,
a contact at least partially retractable internally of said
housing,
connection means associated with said contact for permitting said
connector to operate as an electrical termination,
urging means in said housing for positively urging said contact to
a substantially extended position protruding from said housing,
whereby connection of said contact can be accomplished to another
electrical connector,
trigger means on said connector for additionally retaining said
contact in a position at least partially retracted internally of
said housing and for subsequently allowing extension of said
contact to a position protruding from said housing.
2. The structure as recited in claim 1, wherein said contact is
provided with venting means in communication with the interior of
said housing for dissipating and cooling the evolved arc generated
gases away from a surface of said contact.
3. The structure as recited in claim 1, and further including:
retainer means for retaining said contact in at least partially
protruding relationship with respect to said housing.
4. The structure as recited in claim 1, wherein said connection
means includes a key secured to said contact, and said housing
includes a keyway receiving said key.
5. The structure as recited in claim 4, wherein said contact means
is slidably actuated in respect to said housing, and said key is
slidably received in said keyway.
6. The structure as recited in claim 1, wherein said contact is
provided thereon with a subliming arc extinguishing material.
7. The structure as recited in claim 1, wherein said trigger means
includes a portion protruding from said housing and adjacent to
said contact, whereby upon engagement of the protruding portion
with another electrical connector, said trigger means allows
extension of said contact to a position protruding from said
housing.
8. The structure as recited in claim 7 wherein, said trigger means
includes a pin engaging said contact, a spring urging said pin into
engagement with said contact, and said protruding portion of said
trigger means is provided for disengaging said pin against the
action of said spring, thereby allowing extension of said contact
to a position protruding from said housing.
9. A load break connector, comprising:
a. a housing of dielectric material having an electrical conductor
terminated therein;
b. a male contact slidably mounted within said housing;
c. connection means for connecting said contact to said electrical
conductor;
d. a pulling eye mounted externally on said load break connector in
alignment with the longitudinal axis of said contact and comprising
a pin and a loop of strand material pivotally mounted on said pin;
and
e. first and second mounting means positioned externally on said
housing, said first mounting means being co-planar with and
angularly displaced from said secmounting means, each of said
mounting means adapted to receive said pin.
10. A method of connecting a load break electrical connector to
another electrically associated connector, comprising the steps
of:
a. providing a load break electrical connector having a spring
loaded male contact slidably mounted therein and further having
triggering means operable to release said male contact provided on
said connector;
b. providing an electrically associated connector adapted to
telescopingly receive said male contact, said associated connector
having registering means thereon adapted to engage said triggering
means; and
c. impelling said load break electrical connector into mating
engagement with said electrically associated connector whereby said
registering means engages said triggering means so that said
triggering means releases said spring loaded male contact whereby
said male contact is driven into telescopingly and electrically
engagement with said electrically associated connector.
Description
The present invention relates generally to a loadbreak connector,
and, more specifically, to a loadbreak connector having a contact
for effecting positive electrical connection to an associated high
voltage connector in order to minimize the arc energy and gas
normally generated.
According to the invention, a loadbreak connector is provided with
a spring actuated male contact for positive connection to an
associated high voltage female connector such as a transformer
mounted bushing. A typical loadbreak connector is characterized by
an elongated male contact encircled substantially along its length
by a housing molded from a resilient insulation material with a
conductive shield on the outer surface of the housing. A high
voltage cable is electrically and mechanically secured to the male
contact and is also covered by a portion of the encircling housing.
The housing has an overall elbow configuration enabling a pulling
eye to be located near the apex of the elbow. The pulling eye is
located in alignment with the longitudinal axis of the elongated
male contact, enabling an operator to grasp the pulling eye with a
suitable elongated "shotgun" hot stick tool and forcibly urge the
male contact and encircling housing into positive electrical
engagement with the high voltage connector. Normally, an arc is
struck between the male contact and the female connector both
during loadmake and loadbreak operations. It is accordingly a
requirement that such operations be accomplished with sufficient
speed in order to minimize the duration of the arc. If an
accidental fault closure is experienced the speed of connection
becomes additionally important, since the arc energy level is
significantly increased in proportions to the magnitude of the
fault current. The established hot stick technique is doubly
advantageous since it permits the operator to isolate himself from
the switching system during connection and disconnection thereof,
and enables him to forcibly urge the male contact into engagement
and subsequent disengagement, thereby reducing the arc duration. It
has been the experience in the prior art that the hot stick
technique effectively disconnects a loadbreak connector with a
minimum arc duration. However, during connection, inaccuracies in
alignment of the loadbreak connector and the associated connector,
together with the encountered friction and other obstructive
forces, retard the speed at which positive closure can be effected
by the hot stick technique. As a result, an excessive arc is struck
during normal switching operation which roughens the contacts and
increases contact resistance, thereby reducing the life of the
connection. In the case of a fault closure, increased gas and arc
energy as well as external flashover and flying parts may result
from retarded action and increased contact resistance during normal
switching operations. In the past, there have been several
techniques utilized to further minimize the arc struck during
closure. One such technique resides in providing a dielectric tip
of a subliming material on the male contact which extinguishes the
generated arc. Yet another technique employs the use of passageways
and venting structures for dissipating the arc generating gas away
from the surfaces of the male contact and associated connector.
The present invention provides yet another technique for minimizing
arc generation during closure of a loadbreak connector to an
associated connector. Thus, according to a preferred embodiment of
the present invention, the male contact of the loadbreak connector
is spring actuated to positively matingly engage the connector with
sufficient speed such that arc generation during closure is
advantageously minimized. Trigger structure initially retains the
contact in a partially retracted position in opposition to the
resilient action of a compressed coil spring. When the loadbreak
connector is aligned with the connector and forcibly impelled into
electrical connection by the hot stick technique, the trigger
structure will release the male contact. The compressed coil spring
will immediately expand and propel the male contact into mating
engagement with the connector with sufficient speed so as to
minimize arc generation. Thus, the invention permits closure of a
loadbreak connector with a speed not heretofor attainable by a hot
stick technique.
Other advantages of the invention reside in novel trigger structure
and a novel retainer which retains the male contact in an extended
position and prevents undesired or inadvertant retraction of the
male contact against the action of the coil spring. This feature
allows for closure operation by the hot stick technique if so
desired. As a further feature, the male contact is enclosed within
a shielded housing and includes passageway and venting structure to
dissipate and cool arc generating gases evolved during closure of
the loadbreak connector. The male contact is further provided with
a key slidably received in a keyway which assists in aligning the
male contact with respect to the housing. Additionally, the key
comprises a portion of an electrical connection between the male
contact and one end of an electrical cable to which the loadbreak
is terminated.
It is therefore an object of the present invention to provide a
loadbreak connector having a male contact positively actuated to an
extended position for positive and rapid connection to an
electrically energized or unenergized connector.
Another object of the present invention is to provide a loadbreak
connector having a retractable male contact, together with
retaining structure to prevent undesired retraction of the contact
from an extended position.
Another object of the present invention is to provide a loadbreak
connector with a passageway and venting structure to dissipate and
cool arc generating gases evolved upon connection of the male
contact to an energized connector.
Another object of the present invention is to provide triggering
apparatus capable of initially retaining an electrical contact of a
loadbreak connector in a retracted position, and further capable of
subsequently releasing the contact for positive actuation to an
extended position in order to effect rapid connection to an
associated connector.
Another object of the present invention is to provide a loadbreak
connector with a positively actuated male contact provided with a
key received in a keyway of the loadbreak connector and forming a
part of an electrical connection.
Still another object of the present invention is to provide a
loadbreak connector with a pulling eye mounted externally on the
loadbreak connector and comprising a loop of strand material
pivotally mounted on a pin, with the loadbreak connector having a
first mounting means for receiving the pin and a second mounting
means for receiving the pin which is angularly displaced with
respect to the first mounting means.
Other objects and many attendant advantages of the present
invention will become apparent upon perusal of the following
detailed description taken in conjunction with the description of
the drawings, wherein:
FIG. 1 is a perspective of a preferred embodiment of a loadbreak
connector according to the present invention and particularly
illustrating a pulling eye thereof;
FIG. 2 is a fragmentary elevation of the preferred embodiment
illustrated in FIG. 1 electrically connected to an associated
connector, such as a bushing mounted on a pad-mounted
transformer;
FIG. 3 is an enlarged elevation of the preferred embodiment shown
in FIG. 1 with parts broken away and with parts in section to
illustrate the details of a male contact in a retracted position
and a trigger mechanism capable of retaining the male contact in a
retracted position;
FIG. 4 is an enlarged fragmentary elevation in section of a portion
of the embodiment shown in FIG. 3 to illustrate the details of the
trigger apparatus;
FIG. 5 is an enlarged elevation in section of the embodiment shown
in FIG. 3 and further illustrating the male contact in an extended
position and shown disconnected from an associated contact shown in
fragmentary elevation;
FIG. 6 is a fragmentary detail section illustrating retaining
structure for preventing retraction of the male contact from its
extended position shown in FIG. 5; and
FIG. 7 is an exploded perspective of a portion of the connector
illustrated in FIG. 5 with the male contact in an extended position
and the triggering apparatus and the retaining structure shown
further in detail.
With more particular reference to the drawings, there is
illustrated in FIG. 1 a loadbreak connector generally indicated at
1 and having an elbow shaped configuration. The connector 1
includes a removable voltage test tap cover 2 mounted on the
exterior thereof. Adjacent to the apex of the elbow configuration
and at one end of a generally cylindrical portion 4 of the
connector is provided a pulling eye generally indicated at 6. The
pulling eye includes a recess 8 provided at one end of the
cylindrical configuration portion 4. A pin 10 is retained in the
end of the cylindrical configuration portion 4 and bridges across
the recess 8. To retain the pin 10 in place, the end of the
cylindrical portion 4 of the connector is provided with a
transverse aperture (not shown) which intercepts and bridges across
the recess 8. The pin 10 is thus inserted through the provided
aperture and is provided on each of its ends thereof with a
retaining clip ring, one of which is shown at 12. The rings thus
prevent inadvertant removal of the pin 10 from the provided
aperture. As shown in FIG. 1, the pin includes a portion
intercepting and bridging across the recess 8. A loop 14 of
stranded material such as relatively stiff wire, is pivotally
mounted to the bridging portion of the pin 10. As shown in FIGS. 1
and 3, another aperture 16 is provided transversely in the end of
the cylindrical portion 4 and angularly displaced from the first
provided aperture through which the pin 10 is inserted as shown in
FIG. 1. The aperture 16 also intercepts and bridges across the
recess 8. The pin 10 may alternatively be inserted through the
aperture 16 and thereby provide an alternative or additional
apparatus for mounting the loop 14.
With more particular reference to FIGS. 5 and 7, additional details
of the loadbreak connector according to the present invention will
be described in detail. An elongated male contact 18 is provided
with longitudinal passageway 20 passing longitudinally
therethrough. An electrically conducting end portion 22 is provided
on the male contact 18 and is provided with a transverse vent 24
which provides means for tightening the end portion 22 on the male
contact 18 with a suitable tightening wrench tool. The vent
communicates with the passageway 20 through a passageway 26. For
example, the end portion 22 may be threadably secured, as shown in
FIG. 5, to the elongated cylindrical male contact 18, and provided
thereon with a tapered tip 28 of dielectric material. At the other
end of the contact 18, an external projecting key 30 is
electrically secured, as by brazing to the end of the male
contact.
As shown in FIG. 7, a generally cylindrical housing 32 has a
terminal end 34 and provided with a longitudinal keyway 36 in the
cylindrical surface of the housing 32. The keyway 36 terminates in
a web portion 38 immediately adjacent to the remaining terminal end
40 of the housing 32. The male contact 18 is assembled internally
of the cylindrical housing 32 with the key 30 thereof protruding
into and slidably received within the keyway 36. With the key 30
stopped against the web portion 38, inadvertant removal of the male
contact 18 from the housing 32 is prevented.
As shown in FIG. 5, the elongated coil spring 42 is received
internally of the passageway 20 and is seated against the end of
the passageway 20 which is adjacent to the passageway 26. A
transverse aperture 44 is provided through the cylindrical surface
of the male contact 18 immediately adjacent to the bottom end of
the passageway 20. With reference yet to FIG. 5, the coil spring 42
protrudes from the end of the male contact and extends
longitudinally internally of the housing 32. The terminal end 34 of
the cylindrical housing 32 is provided thereon with an end plug 45
secured in the cylindrical surface of the housing 32. As shown in
FIG. 7, a disc shaped plate 46 provided with a recessed depending
tab 48 is threadably secured by an elongated fastener 50 in
overlying concentric relationship on the end plug 45 of the housing
32. As shown in FIG. 5, the tab 48 registers in the keyway and the
elongated fastener 50 protrudes internally of the housing 32 along
the longitudinal axis thereof and receives thereover the end
portion of the coil spring 42. Thus the coil spring 42 is retained
in alignment with the longitudinal axis of the housing 32 and of
the male contact 18 by the fastener 50 and the recess 20 provided
in the male contact 18.
With more particular reference to FIG. 7 of the drawings, the
details of a retaining mechanism will be described in detail. The
terminal end 40 of the housing 32 is formed with pairs of narrow
elongated notches, one pair of which is shown at 52. Each pair of
notches defines therebetween a relatively rigid finger 54. With
more particular reference to FIG. 6 taken in conjunction with FIG.
7, each finger 54 is formed from a part of the cylindrical surface
of the housing 32 and is slightly radially outwardly flared. The
terminal ends 56 of each spring finger 54 is recessed from the
terminal end 40 of the housing 32. A resilient elongated leaf
spring 58 overlies a corresponding finger 54 and is secured thereto
by a pair of threaded fasteners 60. Each spring 58 includes an end
portion 62 which is deformed to overlie the terminal end 56 of a
corresponding finger 54 and to protrude radially inwardly of the
cylindrical surface of the housing 32 and impinge against the
cylindrical surface of the male contact 18. For example, the edges
of the spring ends 62 may be of arcuate configuration to conform to
the cylindrical surface of the male contact 18. With reference yet
to FIGS. 6 and 7, the male contact 18 if provided thereover with a
surrounding annular collar 64. With the key 30 stopped against the
web portion 38 of the housing 32 as shown in FIG. 7, the collar 64,
as shown in FIG. 6, is received adjacent to and internally of the
surrounding terminal end 40 of the housing 32 and in registration
against the radially projecting ends 62 of the leaf springs 58. The
leaf springs 58 are designed to allow relatively free movement of
the collar 64 in the direction of the fully extended position of
the male contact 18, and to restrict movement of the collar 64 in
the retracted position of the male contact.
With more particular reference to FIGS. 4, 5 and 7, the details of
a triggering apparatus for the preferred embodiment will be
described in detail. The triggering apparatus is indicated
generally at 66 and includes a generally rectangular cantilever
leaf spring 68 having an upturned marginal edge 70. A dowel 72 is
provided with a pair of transverse arcuate surfaced shoulder
portions 74 which, as shown more particularly in FIG. 4, register
against the upturned margin 70 with a threaded fastener 76 securing
the shoulders to the surface of the spring 68. A projecting tapered
ear 78 is formed from the central portion of the spring 68 and
receives thereover one end of a relatively reduced diameter
compressible coil spring 80.
With reference yet to FIG. 7, taken in conjunction with FIG. 4, the
triggering apparatus 66 further includes a generally rectangular
trigger 82 having a reduced rectangular tip 84 at one end thereof.
At the opposite end thereof the trigger portion 82 is provided with
a beveled tip 86. A centrally located notch 88 is provided in the
beveled end 86. A pair of parallel spaced elongated slots 90 are
provided in the central portion of the trigger 82. A pair of
threaded fasteners 92 are slidably received respectively in the
slots 90 and secure the trigger portion 82 in relative sliding
relationship on the cantilever leaf spring 68. The coil spring 80
is retained in compression between the ear 78 and the bottom of the
notch 88. Additionally, the fasteners 92 each secures the trigger
portion 82 slidably on a flattened recessed surface 94 provided on
the cylindrical housing 32. With the trigger thus mounted to the
housing, the dowel 72 protrudes through an aperture 96 of the
housing 32.
With more particular reference to FIG. 7, taken in conjunction with
FIG. 5, a generally annular cap 98 freely receives and guides the
male contact 18 through a central aperture 100 thereof. A generally
reduced rectangular aperture 102 freely receives the trigger
portion tip 84 therethrough. The cap 98 is mounted in overlying
relationship over the terminal end 40 of the housing 32. With
reference to FIG. 7, taken in conjunction with FIG. 5, at least one
strand of braided or otherwise flexible electrical conductor
material 104 is electrically secured to the protruding key 30 by a
weldment 106, for example.
With reference now being made to FIG. 5, the electrical connection
between the male contact and an electrical conductor to which the
load break connector is terminated will be described. With
reference to FIG. 5, the electrical conductor is indicated at 106
and is provided thereover with a layer of insulation material 108.
A connector of any desired type 110 is electrically secured, for
example by a series of compression crimps 112 to the end of the
conductor 106. The remaining end of the conductor 104 is secured to
the end of the connector 110 for example by a weldment 114. With
reference yet to FIG. 5, the connector 110 is located in a first
cylindrical portion 116 of a shielding housing of generally elbow
configuration. The housing 32 and male contact member are located
in a second cylindrical portion 118 of the elbow shaped shielding
housing. The dielectric cap 98 is retained within an annular recess
of the housing portion 118. The enlarged plate 46 is retained in
the end of the second cylindrical portion 118 of the shielding
housing. The recessed tab 48 in registration with the keyway 36 and
the flat edge of the tab imbeds in the shielding housing to prevent
relative rotation of the described structure.
As shown in FIGS. 3 and 5, the shielding housing is provided
thereover with a relatively thick molding of resilient insulation
material. One generally cylindrical portion 119 of the molded
insulation encircles the cylindrical portion 116 of the shield
housing and sealably encircles a portion of the cable insulation
108 which protrudes from the end thereof. The cylindrical portion
119 is further molded with a projecting stem 120 into which is
embedded a probe 122 of a plate 124 serving as a capacitive
divider-type voltage detector. The plate 124 is advantageously
covered with a conductive cap 126 retained by a rib and groove
arrangement 127. The molded portion 119 is contiguous with a second
cylindrical molded portion 128 forming an elbow configuration. The
molded portion 128 terminates in an enlarged diameter lip 130 which
communicates with a generally tapered recess 132 provided with a
rib 133 at the end of the recess 132 which terminates at the
dielectric cap 98. The male contact 18 as well as the trigger tip
84 protrudes into the end of the tapered recess 132 through the
dielectric cap. To complete the connector structure, the elbow
shaped dielectric is provided thereover with a relatively thin
electrically conductive coating 134.
In operation, reference is made to FIGS. 3 and 4 of the drawings.
The male contact 18 is first forcibly retracted internally of the
housing 32 until the dowel 72 registers within transverse aperture
44. Such retraction is accomplished by use of a specially adapted
hand tool or by inserting the connector onto a plugged parking
bushing. Using the hot stock technique, an operator suitably grasps
the loop 14 in the well known manner and registers the tip 28 of
the connector in alignment with and partially inserted within a
high voltage connector shown partially at 136 in FIG. 3. The
operator forcibly thrusts the loadbreak connector into mating
engagement with the connector 136, with the male contact being
received internally of the energized connector and the connector
136 in turn being received internally of the complimentary tapered
recess 132. Ordinarily, despite such forcible engagement,
considerable arcing is experienced as the male contact 18 is
electrically engaged to the connector. However, such arcing is
considerably minimized according to the features of the present
invention, since such forcible engagement causes the head 138 of
the connector 136 to engage against the protruding trigger tip
portion 84. Such action slidably actuates the trigger 82 over the
recessed surface 94 and in opposition to the resilient action of
the coil spring 80. The beveled end 86 of the trigger is thus
received over the arcuate shoulders 74 provided on the dowel 72.
Such action disengages the dowel from the recess 44 provided in the
housing 32 in opposition to the cantilever action of the resilient
leaf spring 68. Such engagement of the dowel 72 immediately
releases the male contact 18 thereby enabling the compressed coil
spring 42 to impel the male contact from a first retracted position
to a second extended position and in mating engagement with the
connector 136. Such action is accomplished with a speed not
heretofore attainable by a static male contact in a loadbreak
connector of the prior art.
Now in connection, the head 138 of the connector 136 will register
against the dielectric cap 98. With the male contact 18 in its
fully extended position, as shown in FIG. 5, the vent 24 thereof is
substantially internally of the connector 136, such that generated
gases which are not dissipated completely in the connector 136, are
dissipated through the vent 24 and the passageways 26 and 20 of the
male contact into the housing 32 and away from the mating surfaces
of the connector 136 and the male contact 18.
With reference to FIG. 6, taken in conjunction with FIG. 7, as the
male contact 18 is impelled from its retracted position internally
of the housing 32 to an extended position as shown in FIG. 5, the
annular collar 64 will be impelled against the radially inwardly
directed leaf spring ends 62, radially deforming the leaf springs
58 radially outward in cantilever fashion about their fasteners 60.
The spring finger ends 62 will thus be removed radially outwardly
of the housing allowing the collar 64 to pass thereby. With the
male contact in a fully extended position, the leaf springs 58 will
resiliently return to their position shown in FIG. 6, and thereby
register the spring ends 62 against the cylindrical surface of the
male contact 18 and behind the collar 64. As shown in FIG. 6, the
spring ends 62 in registration against the collar 64 provide a
retaining structure for preventing inadvertant retraction of the
male contact from its extended position. More specifically, the
annular collar 64 impinges against the spring ends 62, which in
turn impinge against the ends 56 of the relatively rigid fingers
54. Such action stiffens the spring ends 62 and prevents
inadvertant retraction of the collar 64 past the stiffened spring
ends 62. However, when retraction is specifically desired, an
operator, by applying a sufficient force, will cause the collar 64
to forcibly bear against the spring ends 62. Such action eventually
will cause the spring ends 62 to be biased radially outward along
the arcuate surface of the collar 64 allowing the collar to pass
into the housing 32. The male contact will then be readily
retracted into the housing 32 until the dowel 72 registers in the
aperture 44 provided in the male contact. Although a considerable
force is necessary to retract the male contact from its extended
position against the action of the coil spring 42, the spring ends
62 are not damaged since they are stiffened upon impinging against
the ends 56 of the rigid flared fingers 54. Thus, as the male
contact is retracted, the stiffened spring ends 62 will be biased
radially outward, and the leaf springs 58 will deform resiliently
in cantilever fashion. The extension and retraction cycle of the
male contact can be thereby repeated without damage to the
retaining structure provided by the springs 58 and spring ends
62.
What has thus been described and shown are the preferred
embodiments of a loadbreak connector according to the present
invention. It will therefor be appreciated that the aforementioned
and other objects of the present invention have been achieved, and
that the particular embodiments of the invention specifically shown
and described herein are intended as merely illustrative and not
restrictive of the invention, with the result that other
embodiments and modifications of the invention may be made without
departing from the spirit and scope of the present invention as set
forth in the appended claims, wherein:
* * * * *