Bi-switch construction having an auxiliary interrupting device associated therewith

An improved bi-switch construction is provided having an interrupting device arranged in electrical parallel relation therewith so that the circuit through each of the two switches is made through the interrupting device, and, subsequently, the interrupting device is shorted out in the closed-circuit position of the particular switch being operated. During the opening operation, again the interrupting device is brought into play so that a parallel electrical path is provided in shunt relationship to the particular switch being operated through the interrupting device, the interrupting switch assuming the burden of interrupting the circuit; and subsequently the particular switch being operated provides an isolating gap from the interrupting device. The arrangement is particularly desirable when two three-phase switches have a common leg, or terminal, to which one end of the interrupting device may be electrically attached, so that either switch may be operated with the interrupting device serving as a common means for both switches. An improved overcenter spring mechanism is provided for operating the interrupting device in both the closing direction and also in the opening direction for quick-make and quick-break operations of the interrupting device. In one arrangement, the movable contact member of each switch may comprise a rotatable movable blade, which first makes contact with an auxiliary terminal of the interrupting device, while simultaneously the overcenter spring device of the mechanism for operating the interrupting device is being charged. Further rotational movement of the movable rotatable blade of the particular switch effects, through the overcenter spring device, quick closing of the interrupting device, and further rotation of the movable blade effects a bypassing of the interrupting device, so that in the closed position of the particular switch being operated the interrupting blade effects conduction of all of the current to the main terminals of the particular switch being operated to the exclusion of the interrupting device.

BACKGROUND OF THE INVENTION 
Important current developments in underground distribution include 
everything from product modifications to totally new products. Not only 
are systems being changed to achieve optimization and better functioning, 
but also, totally new systems are being tried. In addition, the commercial 
policies of utilities with regard to providing underground facilities, 
particularly underground main feeders and overhead-to-underground 
conversion, are areas of considerable significance. 
Much of the desire for underground three-phase main feeders is caused by 
the unacceptable appearance of overhead main feeders, that must be located 
in areas served by single-phase underground circuits. Main thoroughfares 
through suburban areas also present a growing need for underground 
three-phase feeders to improve appearance. 
The unacceptable appearance, in some areas, of a pad-mounted transformer on 
a front lot line has increased the desirability of a unit residential 
transformer, that can be located next to a home. Growing loads, long 
subdivision construction periods, and high interest rates are combining to 
make the URT systems more practical, particularly when the benefits of 
deferred investment are evaluated. 
Underground switching and protection have assumed ever-increasing 
importance. Until recently, the requirement for an underground three-phase 
switching and protective device has been rather vaguely described as a 
device that permits, for example, the tapping of a 200-ampere underground 
lateral circuit to a 600-ampere underground main feeder, and providing for 
adequate switching and fault protection. In response to a considerable 
need for such a device, development work has resulted in an analysis of 
the functional requirements for underground three-phase switching and 
protective equipment. Results of considerable study indicate that with 
very little increase in total feeder cost, a significant improvement in 
total utility customer outage time can be achieved by the extensive use of 
main feeder tap switches, which may include multiple fused lateral tap 
capability. This improvement in reliability is much greater than one might 
expect from the use of main-line sectionalizing devices. The essential 
reasons for the reliability improvement are the combined effects of 
main-line sectionalizing, with multiple lateral tapping at the 
sectionalizing point. The ultimate end result with all laterals connected 
to the switches is that no utility customer will be cut of service for a 
min-lined fault any longer than it takes to locate the fault and perform 
the necessary switching operation. This same basic approach can be 
extended even further by the judicious looping of the underground lateral 
circuits themselves, so that each lateral circuit is served by two 
different main feeder devices. It is, therefore, desirable to provide 
pad-mounted and submersible three-phase switches, which meet the desired 
foregoing functional specifications. 
As well known by those skilled in the art, in certain classes of switchgear 
and circuit breakers, the use of vacuum "bottles," or vacuum interrupters 
is desirable. The advantages of the "bottles" include reliability, small 
size, short operating stroke, and quiet operation. Disadvantages of the 
use of vacuum "bottles" in switchgear and circuit breakers are the high 
cost, and there being no visible open gap when the circuit within the 
vacuum interrupter is opened. 
Particularly important in the use of vacuum switching is the attainment of 
a visible break employed in both commercial versions of the bi-switch 
arrangement of the present invention, namely the pad-mounted version and 
also the submersible version of the switch. For example, both of the 
models provide, a 600-ampere gang-operated three-phase switch on the 
incoming side, and a similar switch on the outgoing side. Preferably, the 
pad-mounted unit should be relatively low in height, for example, 35 
inches high. Additionally, the submersible unit should be operated from 
the top of the unit with all parts integral to the stainless steel lid, 
when such a metal cover is provided for maintenance purposes. 
The advantages of the unit-residential-transformer concept, or one 
transformer per house, include increased flexibility in handling wide 
ranges of loads, an economic advantage of deferred transformer investment, 
until the house is actually under construction, improved appearance 
compared to a large pad-mounted transformer situated on the front lot 
line, and the elimination of most secondary conductors. 
Apparent disadvantages include the need for more primary cable and loss of 
load diversity, which implies the need for greater transformer capacity. 
It is apparent that the loss of diversity situation can best be handled by 
designing a special transformer for URT application, that is capable of 
carrying the short term, relatively high-peak load of an individual 
residence, rather than attempting to adapt a conventional transformer, 
that originally was designed to serve a number of homes, rather than one 
home. Reliability studies have indicated that the best method of 
connecting the URT to the primary lateral circuit is by means of a fused 
"T"-Tap device located at the point of connection to the primary lateral 
cable. The radial primary service from the lateral to the transformer is 
connected to the primary lateral through, for example, a drawout 
current-limiting fuse. 
Results of economic study of URT application show that the combinations of 
load demand, deferment period, and lot width, which result in the URT 
being more economical than any pad-mounted transformer-secondary system, 
and also any submersible transformer-secondary system. Compared to a 
pad-mounted transformer-secondary system, the URT appears to be economical 
for high loads, large lots and long deferment periods, as might be 
characteristic in a fairly expensive neighborhood. On the other hand, one 
of the main features of the URT system is improved appearance over a 
front-lot-line pad-mounted system. If the front-lot-line pad-mounted 
transformer is unacceptable, than one alternative is to use a submersible 
transformer-secondary system. The URT system, compared to the submersible 
transformer-secondary system, is quite feasible. In this case, it would 
seem that many high-usage homes on large lots could be served economically 
by a URT system, if the deferment period is four or five years or more. 
As a result of an extensive survey of new-product requests by nineteen 
utilities and three utility groups, the latter involving 37 other 
utilities, such a detailed survey resulted in the following requested 
resultant specifications: 
______________________________________ 
Resultant Specifications 
______________________________________ 
Continuous Current 
600a 30, 200a 10 
Momentary 20,000a 30, 12,000a 10 
BIL 95 KV 
Size Vault-mounted; low profile pad 
36 Switches 2 required (in and out) 
10 Taps 3 or 6 solid, switched or fused 
Fuse Rating 30a to 130a 
Fuse Type Current-Limiting 
Enclosure Submersible-non-corrosive 
Pad mounted-mild steel 
Operation of Manual, with a visible break 
Switch 
______________________________________ 
As far as I am aware, the prior art has utilized vacuum "bottles" or vacuum 
interrupters as switches to open and close the circuit, with the vacuum 
interrupters carrying the continuous current through such switching 
devices. In addition, where two switches have a common point for a tap 
connection, each of the switches was provided with its own separate vacuum 
interrupter unrelated to the vacuum interrupter of the other switch. 
Accordingly, it would be desirable to halve or drastically reduce the 
number of vacuum "bottles" required, and consequently to enable two such 
switches to use the same vacuum "bottles" or interrupters to reduce cost 
and size of the equipment. 
In addition, as far as I am aware, the prior art does not show the use of a 
switch such as the movable-blade variety, using an auxiliary interrupting 
device for making or breaking the associated circuit. It would be 
desirable to make and break the associated circuit on the auxiliary 
interrupting device, which might be arranged for a lower rating than that, 
which would be required if the interrupting device were in the series 
circuit itself. 
Moreover, the use of a snap-acting quick-make and quick-break mechanism, 
associated with the auxiliary interrupting device, would be desirable to 
minimize prestriking during the closing stroke of the device and thereby 
reduce the duty imposed upon the switch contacts, and by a quick-break, a 
fast and effective interruption of the resulting arc could be accomplished 
during the opening operation of the switch. 
SUMMARY OF THE INVENTION 
In accordance with preferred embodiments of the present invention, a 
bi-switch device is provided having associated therewith an auxiliary 
interrupting device, which provides a quick-make and a quick-break of the 
circuit. The interrupting device may assume different forms, either oil, 
gas-generating, or the vacuum-"bottle," or vacuum-interrupter variety, 
since the latter is compact, highly reliable and requires very little 
contact stroke. 
The improved bi-switching device of the present invention involves, in one 
particular form, two switches, such as three-phase switches, which have a 
common leg, or terminal. Preferably, the interrupting device has one end 
in fixed attachment or, at least, electrical connection to the common leg, 
or terminal of the two switches. The other end of the interrupting device 
may selectively be electrically connected to either of the two associated 
switches as desired. Moreover, preferably, the improved bi-switching 
device of the present invention utilizes a quick-make and quick-break 
snap-acting mechanism, which provides for a quick-make and quick-break of 
the separable contacts within the interrupting device, such, for example, 
as a vacuum "bottle". The blade-moving action of the main blade of each of 
the two switching devices may be utilized to charge the overcenter-spring 
mechanism of the interrupters to thereby result in a quick-make and a 
quick-break of the separable contacts of the associated interrupting 
device. 
The improved bi-switching device of my invention may assume many forms, for 
example, a pad-mounted version, or a submersible type, which is placed 
deep in the ground and manually operated by an operator from above the 
equipment. 
In addition, the bi-switching equipment of the present invention 
contemplates that the operation of one of the two common switches 
prevents, by an interlocking arrangement, the operation of the other 
associated switch at the same time. 
Accordingly, it is a general object of the present invention to provide an 
improved bi-switching device, which has associated therewith another 
interrupting device of at least some interrupting capability. 
Still a further object of the present invention is the provision of an 
improved bi-switch device of the moving-blade type, in which an auxiliary 
interrupting device is associated to make and break the circuit through 
the aforesaid bi-switching device. 
Another object of the present invention is the provision of an improved 
bi-switching device having a vacuum-bottle interrupting device associated 
therewith, which assumes the burden of making and breaking the circuit 
through the bi-switching device. 
Another object of the present invention is the association of two switches 
having a common leg or terminal, the latter being electrically connected 
to one end of an interrupting device with the other end of said 
interrupting device capable of selectively making electrical engagement 
with the other terminal of each of the associated two switching devices. 
Another object of the invention is to provide an improved switching 
utilizing for interruption a vacuum-interrupter in which the switch has a 
movable contact member which separates from one of the terminals of the 
vacuum-interrupter, a d window means provided so that operating personnel 
may look through the window of the enclosure, and determine whether or not 
the isolating break is in existence. 
Another object of the invention is to provide an improved operating 
mechanism for a circuit interrupter. 
Still a further object of the present invention is the provision of an 
improved overcenter toggle mechanism for a circuit interrupter. 
An ancillary object of the invention is to provide an improved quick-make 
and quick-break operating mechanism for a circuit interrupter utilizing as 
the initiating means a rotary contact-operating member. 
Still a further object of the invention is the provision of an improved 
bi-switch operating equipment in which the component parts thereof are 
disposed in an advantageous compact arrangement within the equipment, so 
that a minimum of actuating movement is required to cause operation of the 
switch. 
Another object of the invention is the provision of an improved 
disconnecting switch having an interrupting unit associated therewith, and 
brought into the circuit only during an intermediate portion of the 
opening and closing operations. 
Still a further object of the invention is to provide an improved device of 
the type specified in the immediately preceding paragraph in which a 
quick-make and quick-break toggle-operating mechanism is associated with 
the interrupting device. 
Still a further object of the present invention is the provision of an 
improved quick-make and quick-break operating mechanism to be used with a 
switching device of the type proposed hereinbefore or, perhaps, for use 
only with a single switch. 
Another object of the present invention is the provision of an improved 
quick-make and quick-break operating mechanism, which is actuated in 
accordance with the movement of the movable blade of either of the two 
switching devices. 
Another object of the present invention is the provision of two switches 
having the common use of vacuum bottles, so that the number of vacuum 
bottles required is reduced or halved in number. 
Still a further object of the present invention is the provision of an 
improved manually-operable "T"-type switching construction, in which each 
of the two switches may be manually operated to the exclusion of the other 
associated switch by a novel mechanical interlocking arrangement. 
Still a further object of the present invention is the provision of an 
improved quick-make and quick-break operating mechanism for any type of 
switching device. 
Still another object of the present invention is the provision of an 
improved "T"-type switching device, which is suitable for either 
submersible environments or for pad-mounted environments. 
Further objects and advantages will readily become apparent upon reading 
the following specification, taken in conjunction with the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to the drawings, and more particularly to FIG. 1 thereof, the 
reference numeral 1 generally designates the "T" bi-switch construction of 
the present invention. In the particular version of the switch shown in 
FIg. 1, the switch is adaptable for submersible applications, where it is 
positioned in a vault down in the ground, and manually operated from 
above. Generally there are provided two sets of incoming and outgoing 
feederterminals 2, 3, 4, 2A, 3A, 4A, and additional terminals 5, 6, and 7 
for lateral single-phase taps. As illustrated in FIG. 15, it will be 
apparent that three incoming feeder terminals 2, 3, 4 are provided, which 
connect to interrupting devices X1, Y1 and Z1, to enable connection with 
lateral taps, such as the lateral terminal bushings 5, 6 and 7. Additional 
lateral taps may be provided, such as the lateral taps 5A, 6A and 7A. The 
outgoing feeder terminals 2A, 3A, 4A are provided so that when the 
interrupting devices X1, Y1, Z1 are closed, through circuits are provided, 
including the incoming feeder terminals, through the interrupting devices 
X2, Y2, Z2, and continuing through the outgoing feeder terminal 2A, 3A and 
4A. 
It will also be noticed that the lateral taps, which may be either 
single-phase laterals, of three-phase tap-offs, may be connected to the 
three circuits. Also, as shown in FIG. 16, two sets of incoming feeder 
terminals, such as the feeder terminals 2, 3, 4, 8, 9, 10, may be 
connected through the interrupting devices X1, Y1, Z1, X2, and Z2 to the 
lateral tap-offs 5, 6, 7, 5A, 6A, 7A. The lateral tap-offs may constitute 
single-phase lateral circuits, or, if desired, three-phase circuits. Thus 
selectivity is provided in FIG. 16, so that the laterals may connect with 
either the incoming feeder terminals 2, 3, 4, or the interrupting devices 
may be opened, and the lateral taps 5, 6, 7 may be connected with the 
other incoming feeder terminals 8, 9, 10. A versatility of switching 
arrangements is thereby obtained. 
As will be illustrated more clearly hereinafter, the switches, which are 
diagrammatically shown as X1, X2, Y1, Y2, Z1, Z2 in FIGS. 15 and 16 are, 
in fact only one set of such devices in the structural arrangement of the 
invention, instead of two sets, as diagrammatically indicated in FIGS. 15 
and 16. As a result, an economical reduction, or halving, of the number of 
interrupting devices X, Y, Z are consequently provided. 
With reference to FIGS. 2, 3 and 4 of the drawings, it will be apparent 
that there is provided two three-phase switches, generally designated by 
the reference numerals 20 and 21 which have a common leg or terminal 22, 
to which may be tapped single-phase laterals 23, 24 and 25 (FIG. 2) for 
distribution circuits. Associated with one of the three-phase switches 20 
are the three terminal bushings 2, 3 and 4 which, for example, may be 
adapted for a 600-ampere rating. The terminal bushings 5, 6, 7 for the 
lateral circuits, as more clearly shown in FIG. 2, may, for example, be of 
a lower rating, say 200-amperes. Thus, it is possible to connect the 
laterals 5, 6, 7 with either of the two main feeder circuits F1 or F2 
(FIG. 16) which are connected to the two pairs of feeder terminals 2-4, 
8-10. 
In the improved switch construction 1 of the present invention, the usual 
number of vacuum "bottles" 27, or other interrupting devices (as described 
later), is halved by the conjoint use of the bottles 27 selectively with 
either of the two movable blade assemblies 28, 29, which are rotatively 
mounted upon rotatable shaft assemblies, designated by the reference 
numerals 31 and 32. These shaft assemblies 31, 32 are driven, in the 
embodiment of the invention shown in FIG. 2, by two chain drives. One 
(FIG. 2) chain-drive 33 connects to a sprocket wheel 34, affixed to the 
insulator assembly, upwardly to an operating shaft 35, which has provision 
for a handle 36. Thus, by a manual operation of the handle 36, keyed to 
the operating shaft 35, such rotary motion may be transmitted, generally 
by means of the chain 33, to the lower-disposed rotatable shaft assembly 
31 carrying, in an insulated manner, the several rotatable blade 
assemblies 28. The other operating shaft assembly 32 has its own chain 
drive for operating the several blade assemblies 29. 
The blade assemblies 28 are more clearly illustrated in FIGS. 5-7 of the 
drawings. The movable blade assembly 28 (FIG. 26, 26A) may, for example, 
comprise two spaced conducting blade segments 37, which are urged together 
by pin-and-washer biasing assemblies 38 FIGS. 26A, so that during their 
rotary motion they will make good contacting engagement with the auxiliary 
jaws, or auxiliary terminals 40, which are connected to the upper movable 
contacts 42 of the several vacuum interrupters 27. Thus, as illustrated 
more clearly in FIG. 5, rotary motion of the blade assembly 28 first makes 
conducting engagement with the auxiliary jaw 40, and further closing 
rotary movement, as shown in FIGS. 6 and 7, causes finally engagement of 
the rotary blade assembly 28 with the lower main jaw 22 of the switch. A 
flexible conductor 44 may interconnect the upper conductor stud 46 to the 
blade assembly 28, so that current will pass from the upper feeder 
terminal bushing 2 through the flexible strap 44 to the movable blade 
assembly 28 and thence through the stationary main jaw, or terminal 22 and 
consequently to one of the lateral straps 23, 24 or 25. FIG. 2 may be 
referred to in this connection. 
In accordance with the improved switch construction 1 of the present 
invention, there is provided an improved quick-make and quick-break 
operating mechanism 48, which is operated in response to motion of the 
insulator assemblies 31 or 32. In more detail, with reference to FIG. 4, 
it will be observed that there is provided a crank-arm 50 affixed to the 
rotatable shaft assembly 31, 32 which is pivotally connected, as at 51, to 
a push-rod 53, the latter preferably comprising a pair of spaced 
push-links 53a, 53b (FIG. 2), the upper ends of which have a guide or 
thrust pin 55 extending laterally therethrough. As shown in FIG. 4, the 
guide pin 55 moves within a guide slot 56 provided in a guide plate 57 
(FIG. 14) fixed to the main frame 60 of the switch 1. As a result, with 
respect to FIG. 5, which shows a closing operation of the switch 20, the 
guide pin 55 enters the recess 61 in the actuating toggle-lever plate 63, 
which is shown in more detailed fashion and enlarged in FIG. 9 of the 
drawings. The thrusting action of the push-links 53a, 53b causes 
counterclockwise rotary motion of the actuating toggle-lever plate 63, 
which carries the toggle-knee pin 64 of an overcenter toggle linkage 66 
overcenter to result in a first compression of the telescopic-type toggle 
compression spring 67, and subsequently a quick movement of the toggle 66 
overcenter, as illustrated in FIG. 6 of the drawings. Continued clockwise 
rotary closing motion of the shaft assembly 31 will again cause, through 
the interconnection of the pivot pin 55 within the recess 61 of the 
actuating toggle lever plate 63, this time clockwise rotation of the 
toggle-lever plate 63 to again carry the toggle linkage 66 overcenter to 
its original position. This constitutes a double-toggle action of the 
over-center toggle linkage 66. As will be brought out more clearly 
hereinafter the first toggle actuation closes the contacts 42, 43 within 
the vacuum bottle 27, and the second toggle actuation snap-opens the 
contacts 42, 43 within the vacuum bottle 27. 
Extending longitudinally centrally of the switch frame 60 is a 
contact-operating shaft, designated by the reference numeral 69 and having 
a torsion-spring connection 70 with each of the movable contacts 42 of the 
several vacuum interrupters 27. The rotary contact shaft 69 is connected, 
by means of arms 71 and insulating links 72 to the upper movable contacts 
42 of the vacuum interrupters 27. Generally, it is desirable, during the 
closing operation for the circuit to be made within the vacuum 
interrupters 27, as illustrated more clearly by FIGS. 5, 6 and 7 of the 
drawings. With respect to these drawings, it will be observed that first 
the blade assembly 28 engages the auxiliary jaw 40 and transfers the 
current through the vacuum interrupter 27, as shown in FIG. 6, and 
finally, upon the opening of the vacuum interrupter 27 (FIG. 7), the blade 
28 closes on the main jaw 22 to thereby close the switch 20. 
Due to the fact that there is spring pressure 73 exerted on the separable 
contacts 42, 43 within the vacuum interrupters 27 by virtue of the biasing 
action exerted by the torsion springs 73, it is desirable to latch the 
operating shaft 69 in the contact-closed position, as shown in FIG. 6 
until the full thrust of the overcenter spring 67 is obtained. With 
respect to FIGS. 5-7, it will be observed that the latching action is 
achieved by pivotally-mounted latch levers 76, 77, which engage corner 
portions 79, 80 (FIG. 13) provided on the rotatable shaft-operating lever 
82, the latter being fixedly keyed to the contact-operating shaft 69. 
In more detail, the shaft-operating lever 82, illustrated in FIG. 13 of the 
drawings, is keyed by a pin 83 (FIG. 6) to the contact operating shaft 69. 
The shaft operating lever 82 has a recess 85 provided therein having two 
end abutment portions 85a and 85b which are struck by the toggle knee pin 
64 of the toggle linkage 66 in its overcenter action. This rotates the 
contact shaft 69 and causes opening and closing of the contacts 42, 43 
within the vacuum-interrupting unit 27. 
With respect to the dotted lines 52 which show the path of movement of the 
thrust pin 55 in FIG. 6, taken in conjunction with FIG. 7, it will be 
observed that the actuating-toggle lever plate 63 is engaged by the thrust 
pin 55 a second time and thus causes overcenter action of the toggle 
linkage 66 a second time, while the shaft-operating lever 82 is maintained 
in a latched-fixed contact-closed position by the upper latch lever 76 as 
shown in FIG. 6. 
Following overcenter action of the toggle linkage 66 the second time, an 
arm 84 (FIG. 9) secured fixedly to the actuating toggle lever plate 
assembly 63, releases the upper latch arm 76 and thereby permits snap 
rotation contact-opening motion of the shaft-operating lever 82. This is 
more clearly seen in FIGS. 6 and 7 of the drawings. 
It will be observed that the guide plate 57 (FIG. 14) has two guide slots 
56 and 86 provided therein to accommodate the thrust pins 55, 88 for each 
of the two thrust linkages 53 associated with the two switches 20, 21. As 
a result, should one switch be actuated, the interposition of the cam 
portions 90, 91 (FIG. 9) will prevent the other thrust pin 55 or 88 from 
being manually actuated. An interlocking arrangement is consequently 
provided, so that only one switch 20 or 21 can be operated at a time. It 
is only following the completion of the opening or closing motion of one 
switch 20 or 21, that the other switch can be brought into "play" and 
operated. 
The crank-arm assembly 63 is more clearly shown in FIG. 9 of the drawing, 
and comprises, generally, the crank-arm proper 63a affixed to a sleeve 59, 
which pivots about the shaft 69, the sleeve 59 having the latch-releasing 
arm 84 fixedly secured thereto. In other words, the crank-arm assembly 63 
is loosely mounted about the contact operating shaft 69, and the latch 
release arm 84, forming a part of the crank-arm assembly 63, serves to 
release the latch levers 76 and 77, as more clearly shown in FIGS. 4-7 of 
the drawings. 
FIG. 13 more clearly illustrates the shaft operating arm 82, which is 
keyed, or otherwise fixedly secured, to the contact-operating shaft 69. As 
shown in FIG. 13, the shaft operating arm 82 has a hub portion 81, which 
has a bore opening 81a therethrough to accommodate a keying pin 83, which 
also passes through the contact-operating shaft 69 itself. As a result, 
the operating arm 82 is fixedly secured to the contact operating shaft 69, 
and positively causes the opening and closing rotative motions thereof. 
As will be apparent, the crank arm 63 and the telescopic spring guide 
member 102a collectively form a spring toggle mechanism 66. When the crank 
arm 63 and the telescopic spring guide member 102-102a are at an angle to 
each other, as shown by the full lines in FIG. 4, the compression spring 
67 will act to force the operating arm 82 upwardly against the stop member 
30. However, when the crank arm 63 and the telescopic spring guide member 
102-102a are moved such that the angular relation is opposite to that 
shown, the force of the compression spring 67 will hold the operating arm 
82 against the lower stop 39. 
The telescopic spring guide member is pivotally connected by a knee pivot 
pin 64 to the outer periphery of the crank-arm assembly 63. The telescopic 
spring-guide member comprises a rod portion 102, which is telescopically 
received in a sleeve portion 102a, the latter being fixedly pivoted, by a 
stationary pivot pin 104, to a pair of downwardly extending flanges 101 
secured, as by welding, to the frame 60 of the bi-switch structure. Thus, 
counterclockwise rotative motion of the operating arm 63 will carry the 
telescopic spring-guide member 102 overcenter, thereby causing a 
collapsing of the rod member 102 within the pivotally-mounted sleeve 
member 102a through an overcenter position, at which time the compression 
spring 67 will expand to force the crank-arm 63 to its other position. 
The vacuum interrupter or vacuum "bottle" 27 is of the type well recognized 
in the art. Its internal construction may be set forth, for example, in 
U.S. Pat. Nos. 3,246,979 and 3,462,572. It will be observed that the 
stationary contact end 27a of the vacuum interrupter 27 is affixed to the 
main common leg, or terminal 22 having at its opposite ends the two jaw 
plates 22a, 22b which make sliding contacting engagement with either of 
the rotary blade assemblies 28, 29. The upper end 27b of the vacuum 
interrupter 27 provides a guiding action 93 for the movable contact 42 
which is connected by a flexible strap 95, to the stationary auxiliary 
jaws 40 which make contact with the blade assemblies 28, 29 at an 
intermediate part of the opening and closing strokes. 
The two latch arms 76, 77 are biased inwardly into engagement with the 
shaft-operating lever 82 by means of a tension spring 97 having its ends 
affixed to apertures 99, 100 suitably provided in the intermediate 
portions of the latch levers 76, 77. 
The overcenter spring 67 is of the telescopic type, wherein a rod 102 
carrying a pin-and-spring seat 103, is forced outwardly into a sleeve 102a 
thereby effecting compression of the spring 67 against the other pivot pin 
104, the latter constituting the other spring seat for the biasing 
compression spring 67 and stationarily pivotally supporting the left hand 
end of the sleeve 102a to a bracket 101. 
FIGS. 33-38 illustrate, sequentially, the various positions of the 
operating linkage 48 during the closing operation of the interrupting 
switch 20. With reference to FIG. 33, it will be noted that at this point 
the vacuum bottles 27 are open, and the interrupting switch 20 is also 
open. The push-rod linkage 53 is such that no engagement is present with 
the actuating-toggle lever-plate 63, and either switch 20 or 21 may be 
freely operated as selected by maintenance personnel. 
Assuming, for instance, that it is desirable to effect a closing operation 
of the interrupting switch 20, the clockwise rotation of the insulator 
assembly 31 will effect, generally, upward movement of the push-rod 
linkage 53, causing the upward movement of the thrusting guide-pin 55 to 
cause it to enter the recess 61 in the actuating-toggle lever-plate 63. 
This engagement is illustrated in FIG. 34 of the drawings. In other words, 
FIG. 34 merely shows the initial abutment of the thrusting guide-pin 55 
engaging the recess 61 of toggle lever assembly 63. 
With reference to FIG. 35 of the drawings, it will be noted that in the 
position of the linkage parts shown, the over-center toggle-linkage 66 has 
been moved over-center. The latch-release arm 84 has effected 
disengagement of the lower latch arm 77 from the lower abutment portion 80 
of the shaft-operating lever 82; and the shaft-operating lever 82 has been 
rotating the operating shaft 69 to close the contacts of the vacuum 
bottles 27. 
With reference to FIG. 36 of the drawings, it will be noted that the 
continued clockwise rotation of the insulator shaft assembly 31 is now 
effecting the beginning of the double-toggle action of the toggle-linkage 
66 by pulling the actuating-toggle lever-plate 63 in the opposite 
clockwise direction about the contact-operating shaft 69. With respect to 
FIG. 37, it will be observed that in the position of the linkage parts 
shown, the overcenter toggle-linkage has now gone over-center in an upward 
direction, causing the latch-release arm 84 to effect release of the upper 
latch-arm 76, and thereby tripping the contacts of the vacuum interrupters 
27 to the open position. 
FIG. 38 illustrates the fully closed-circuit position of the interrupting 
switch 20, with the lower latch-arm 77 holding the vacuum bottles 27 open 
by engagement of the latching portion 77a with the abutment portion 80. In 
FIG. 38, it will be noted that the guide pin 55 has been retracted from 
the recessed portion 61 of toggle lever plate 63 to a disengaged position 
therefrom. 
With respect to current flow in the several FIGS. 33-38, it will be 
observed that in FIG. 33 no current flows through the interrupting switch 
21, since the moving contact blade 28 is separated from the auxiliary jaw 
contact 40. In FIG. 34, the moving blade 28 has engaged the auxiliary jaw 
contact 40, but since the contacts of the vacuum bottles are open, no 
current flows through the switch. However, in FIG. 35, the vacuum bottles 
are closed, so that in FIG. 35 there is full current flow through the 
switch 20 by way of the vacuum bottles 27. With respect to FIG. 36, the 
rotatable blade-assembly 28 has disengaged from the auxiliary jaw contact 
40, but has made contact with the main stationary jaw contact 22, thereby 
carrying full current flow through the interrupting switch 20. In FIG. 36, 
however, the vacuum bottles are closed, but are not carrying any current 
in view of the disengagement between the upper tip portion of the blade 
assembly 28 and the auxiliary jaw contact 40. 
FIG. 37 illustrates the almost closed position of the interrupting switch 
20, with the vacuum bottles 27 opened, current however passing through the 
interrupting switch 20. As mentioned, FIG. 38 illustrates the fully-closed 
position of the interrupting switch 20 with he vacuum bottles, as before, 
in the open-circuit position. 
Generally, a frame 60 is provided, which supports the several component 
parts of the two switches 20, 21 and the centrally-provided vacuum 
interrupters 27. In more detail, the frame comprises a number of angle 
irons 105 to 116 (FIG. 8) with post insulators 117-119, the latter 
supporting the vacuum interrupters 27 in a generallyvertical position, as 
shown more clearly in FIG. 8 of the drawings. 
The use of torsion springs 73 for providing the proper contact pressure is 
set forth and claimed in U.S. Pat. application W.E. Ser. No. 41,963 filed 
May 10, 1971, Ser. No. 141,686 by Charles Bice, Robert Few and Frank 
Senchur. By the provision of torsion springs 73 as contact-compression 
springs, there is provided a considerable insulating distance between the 
upper rotary shaft assembly 69, which is at ground potential, and the 
upper ends 27b of the vacuum interrupters 27, which at times, are at high 
voltage. 
In order to provide a prior movement of the thrust linkage 53 before the 
contact-blade assemblies 28, 29 are moved there is provided a lost-motion 
arrangement 122, as shown in FIGS. 18 and 19 of the drawings. A shaft pin 
124, passing through the shaft 32, makes engagement with recesses 127, 128 
provided in a laminated block 129 to provide an initial slight preceding 
motion of the operating linkage 53 before a subsequent rotary movement of 
the operating-blade shaft assemblies 31, 32. This was felt desirable to 
provide the prior timing. However, it is to be clearly understood that the 
provision of such a lost-motion connection 122 is not necessary to the 
utilization of the invention, but was merely employed as an expedient in 
the commercial version to obtain the proper operating sequence. 
The switch construction 1 of the present invention has wide application. 
FIG. 32 illustrates the switch arrangement as applied to a pad-mounted 
construction. It will be observed that in this instance, the switch 
arrangement 130 is such that the primary feeder bushings 2, 3, 4, 2A, 3A, 
4A extend out the side of the enclosure 137, with the window 132 providing 
a visible view of the isolating switch gap 134 or 135, (FIG. 5) which is 
of course, desirable for assuring to operating personnel that high voltage 
is removed from the laterals 5, 6, 7, 5A, 6A and 7A. The terminal bushings 
5, 6, 7 for the laterals 5, 6 and 7 are provided to the right of FIG. 32. 
If desired, fuses (not shown) may be associated with the laterals 5, 6 and 
7 and preferably are of the current-limiting type. 
FIG. 17 generally shows the arrangement of the improved switch construction 
1, as provided in a distribution system 150. It will be observed that the 
primary feeders 151, 152 and 153 extend from the generating stations 154, 
155 and 156, and the switch constructions of the present invention are 
desirable to sectionalize intervening portions of the primary feeders and 
to obtain a selectivity in regard to the laterals. 
FIGS. 27, 28, 29 and 30 show an alternate overcenter mechanism utilizing an 
over-center extension spring mechanism. As the push links 53 engage the 
slot 201 in the spring-anchor plate 202 and rotate it clockwise as viewed 
in FIG. 29, the spring anchor pin 204 moves through the line bisecting 
spring anchor pin 206 and contact-operating shaft 69 at which time the 
spring force 208 causes counterclockwise rotation of the shaft operating 
lever 210 to which spring anchor pin 206 is affixed. Continuing switch 
operation causes push links 53 to retract from the mechanism thus rotating 
the spring anchor plate 202 in a counterclockwise direction which allows 
the spring anchor pin 204 to cross back through the line bisecting spring 
anchor pin 206 and contact-operating shaft 69 resulting in a clockwise 
rotation of the shaft operating lever 210. The above-described 
counterclockwise then clockwise rotation of the contact-operating shaft 
93, closes then opens the bottles respectively, as is necessary for the 
basic operation of the switch. 
From the foregoing description, it will be apparent that there has been 
provided an improved switch construction 1 in which the interrupting 
device 27, 160 may be of a reduced rating because they carry current only 
for such a short time. In other words, although the primary feeders may be 
suitable for 600-ampere capacity, nevertheless, because of the short time 
duration, that the vacuum interrupters 27 are in circuit, they may be of 
the 200-ampere rating, even though they will be carrying 600 amps during 
the brief time that they are in the circuit. Moreover, it will be apparent 
that there results, from the foregoing construction, halving of the usual 
number of interrupting devices 27, which are required, inasmuch as either 
switch 20, 21 may use the same set of vacuum-interrupting devices 27. 
It will be observed that the bi-switch construction 1 of the present 
invention is particularly adapted, for example, to 600/200 amp 3330 T-Tap 
switch applications in underground systems for line sectionalizing 
purposes of three-phase distribution circuits. The application of this 
bi-switch construction 1 increases the reliability of service to 
underground customers by providing flexible switching of electrical 
circuits. The switching is safe because vacuum switching and air 
dielectric is used in the isolating gaps. Visible break of the switch 
contacts through the window 132 is also possible. 
Advantageous constructional features of the bi-switch device 1, 130 of the 
present invention are as follows: 
1. Vacuum load-switching of three phase-600 ampere circuits are possible. 
2. A visible air break is provided. 
3. Air dielectric may be used in the isolating gap. 
4. 600 amp bushings are adaptable for ESNA connectors. 
5. 200 A and P wells for bushings are adaptable for load or non-load break. 
6. Non-corrosive housing is used for submersible unit application. 
7. Attractive low-profile pad-mounted unit with a completely dead front. 
8. Electrical ratings, which for one typical example, may be provided are 
indicated below: 
Electrical Ratings: 
1. Design Voltage Rating: 15.5 KV RMS 
2. Continuous Current 
Feed through: 600 Amps RMS 
Tap: 200 Amps RMS 
3. Momentary Current Rating: 20,000 Amps RMS 
4. One Second Current Rating: 10,000 Amps RMS 
5. One Minute 60 Cycle Withstand. 35 KV 
6. Basic Impulse Level: 95 KV 
The improved bi-switch construction of the present invention is, as 
mentioned, adaptable for many types of environments, such as the 
submersible or the pad-mounted switch construction. The same interrupting 
units 27 may be used for the operating of either the switch assembly 20 or 
alternatively, with the switch assembly 21. Thus, the number of 
interrupting units 27 is thereby reduced, and economies are thereby 
achieved. It is to be clearly understood that the present invention is not 
restricted in its use only to the use of vacuum-type circuit interrupters 
27. For example, other types of interrupters may be used. FIG. 31 shows an 
alternate type of interrupting structure in which instead of vacuum 
interrupters 27 being used, in their stead the interrupting units 160 are 
employed. 
The alternate-type of interrupting unit 160 comprises a generally 
cylindrical-type casing 200, formed of a gas-evolving material, for 
example "Delrin". Other materials, such as fiber, could be used, however. 
As shown in FIG. 31, a finger-type stationary contact 43 is provided 
cooperably with a movable contact 42a, assuming the form of a sleeve 
surrounding a plug 205, also formed of a suitable gas-evolving material, 
such as, for example "Delrin". 
During the opening operation, it will be obvious that the upward movement 
of the movable cylindrical contact 42a within the bore 210 of the casing 
200 will establish an arc, designated by the reference numeral 26, and 
this arc will generate, because of the heat evolved, evolution of 
considerable gas from the gas-evolving casing and plug materials. The 
evolution of such evolved gas will quicklybring about arc extinction. 
Thus, the bi-switch construction 1 is not restricted to the use of vacuum 
"bottles 27" but may encompass other alternate forms of interrupting 
devices, such as the gas-evolving single-break device 160 of FIG. 31, 
which may be alternately used in place of the vacuum "bottle" 27, 
illustrated in FIG. 5-7 of the drawing. 
Additionally, altough the mechanism 66 includes an overcenter toggle-type 
mechanism, nevertheless, for certain applications, an overcenter 
spring-arm mechanism 200 may be utilized, as illustrated in FIGS. 27-30 of 
the drawings. 
Although there has been illustrated and described specific structures, it 
is to be clearly understood that the same were merely for the purpose of 
illustration, and that changes and modifications may readily be made 
therein by those skilled in the art, without departing from the spirit and 
scope of the invention.