US3070680A

US3070680A - Switch gear

Info

Publication number: US3070680A
Application number: US796068A
Authority: US
Inventors: Joseph R Mcbride; Bolt Donald G De
Original assignee: AB Chance Co
Current assignee: AB Chance Co
Priority date: 1959-02-27
Filing date: 1959-02-27
Publication date: 1962-12-25
Anticipated expiration: 1979-12-25

Description

DECl 25, 1962 J. R. MGBRIDE ETAL SWITCH GEAR 7 Sheets-Sheet 1 Filed Feb. 27. 1959 J. R. MCBRIDE ETAL Dec. 25g, 1962 SWITCH GEAR 7 Sheets-Sheet Filed Feb. 27, 1959 DeC- 25, 1962 J. R. MGBRIDE ETAL 3,070,680

SWITCH GEAR '7' Sheets-Sheet 3 Filed Feb. 27, 1959 FIG. IO.

Dec. 25, 1962 .1. R. MGBRIDE ETAL 3,070,680

SWITCH GEAR Filed Feb. 27, 1959 vsheets-sheet 4 Dec. 25, 1962 J. R. MOBRIDE ETAL SWITCH GEAR '7 Sheets-Sheet 5 Filed Feb. 27. 1959 a /LJ/// Sci FIG.

Filed Feb. 27, 1959 Dec- 25, 1962 J. R. MGBRIDE ETAL 3*,0705680 SWITCH GEAR 7 Sheets-Sheet 6 J. R. MCBRIDE ETAL SWITCH GEAR '7 Sheets-Sheet 7 Filed Feb. 27, 1959 w mn `nm w S 3 w mv /u f. E. S E. mr n E. m: mw E :0 `\L O ww E m9 E G. 5 n: S, w+. m2 v9 D .m.\ r Wm- O L Q ww. n! mE lil'raited States Patent Oiilce 3,070,680 Patented Dec. 25, 1962 3,070,680 SWITCH GEAR `l'oseph. R. McBride, Leawood, Kans., and Donald G. De Bolt, Centraiia, Mo., assignors to A. B. Chance Company, Centralita, Mo., a corporation of Missouri Filed Feb. 27, 1959, Ser. No. 796,068 28 Claims. (Cl. 200-146) This invention relates to switch gear, and with regard to certain more specific features to sectionalizing switches for electrical distribution systems, being an improvement upon switch gear of this class such as shown, for example, in U.S. Patents 2,470,576, 2,727,105 and 2,783,322.

Among the several objects of the invention may be noted the provision of an improved sectionalizing switch adapted primarily, although not exclusively, for singlepole mounting and multi-phase gang operation; the provision of a switch of the class described adapted to interrupt not only line charging currents and the like (as heretofore was the case) butalso substantial loa-d currents; the provision of a switch of the class described which under many load conditions does not require, prior to switch opening, that loads be interrupted by an oil circuit breaker or like adjunct; the provision of a switch of the class described which simplifies the programming of inspection and repair operations; and the provision of a switch of this class which may be relatively inexpensively produced in a form adapted for reliable operation over long periods without contact burning. Other objects and features will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the elements and combinations of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described, and the scope of which will be indicated in the claims.

In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated,

FIG. 1 is a top plan view of one of several identical sections of the switch, shown in closed position, the dotted lines showing certain open positions;

FIG. 2 is a vertical section taken on line 2-2 o-f the switch section illustrated in FIG. l, two switch components thereof being omitted for clarity of illustration;

FIG. 3 is an enlarged detail Sectio-n taken on line 3-3 of FIG. 2, showing certain jaw parts;

FIG. 4 is a fragmentary enlarged plan view of a trip mechanism employed in the invention;

FIG. 5 is a vertical section taken on line 5-5 of FIG. 4, showing a vacuum-break switch below said trip mechanism;

FIG. 6 is a vertical section taken on line 6 6 of FIG. 4, showing details of said trip mechanism;

FIG. 7 is an enlarged detail section taken on line 7-7 of FIG. 5;

FIG. 8 is a View similar to FIG. 4, showing an advanced position of parts during switch-opening movement;

FIG. 9 is a cross section taken on line 9 9 of FIG. 8;

FIG. l0 is a view similar to FIG. 8, showing a further advanced position of parts;

|FIG. 11 is a cross section taken on line 11-11 of FIG. l0;

FIG. l2 is an isometric view of certain linkage parts;

FIG. 13 is a simplified wiring and structural diagram of one section of the switch form shown in FIGS. 1-12;

FIG. 14 is a plan view similar to FIG. l but showing an alternative form of the invention; and,

FIG. 15 is a simplied wiring and structural diagram of one section of the switch form shown in FIG. 14.

'Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Switches such as shown in said patents are generally referred to as gang operated air-break switches, employed in gang operated banks of sections mounted one above another on individual supporting poles, usually for multiphase switching, to sectionalize various portions of an electrical distribution system, primarily for purposes of inspection and repair. They are useful in conserving switch clearance space between phases, and they conserve right-of-way spacel Heretofore such switches had been limited to interrupting line charging currents, leakage currents, transformer exciting currents and the like. However, such air-break switches have not been capable of reliably interrupting load currents of magnitudes approaching an appreciable percentage of the full load rating of the switch, without the necessity for rst opening the usual oil circuit breakers located at the power stations or substations of the system. In such cases the oil circuit breakers or the like were opened prior to opening the air-break switches. 'Ihis involved more or less complicated programming in order to isolate a portion of a system, a requirement which the present invention minimizes.

As is known in the art, a switch of this general class, as formerly made, might for example have a rating of 400, 600 or 1200 amperes, which meant that the switch could carry such a load continuously when closed. It did not mean that the switch would normally interrupt such a load, but would require prior operation of the associated oil circuit breaker or the like, as above stated. by means of the present invention, loads may be interrupted up to full load rating in many cases; for example in the cases of 400 to 600 ampere switches; and, in the case of higher ratings, such as a 1200 ampere switch, a large percentage, such as 50% of the full load, may be interrupted, besides, in any case, interrupting the line charging currents, leakage currents and transformer exciting currents.

Referring now more particularly to FIGS. l and 2, there is shown at numeral 1 a typical pole on which the one complete section of the invention is mounted. FIGS. 1 and 2 show the section on the pole 1 for control of one electrical phase (single-phase) operation. It will be understood that other sections required for additional electrical phases of operation (as, for example, three-phase operation) are identical, being mounted one below the other on said pole. This will also be clear from an examination of said Patents 2,470,576 and 2,783,322. In view of the above, description of one section only of the invention will be sulicient for a complete understanding of it.

At numeral 3 is shown a typical horizontal platform structure supported upon a bracket 5 suitably attached to the pole 1, being braced as shown at 7. There are three identical platform arrangements such as (3, S, 7), one

under the other for each section, the uppermost one only of which is shown in the drawings.

Mounted `at the corners of each triangular platform 3 are three vertically positioned rotary insulators 9. The rotatable supporting bearings therefor are indicated at 11. Each of the insulators 9 belongs vto one of three main air-break switches known in the art as being of the side-break type, and being generally such as shown, for example, in U.S. Pa-tent 2,786,121. All three of these air-break switches are shown in FIG. 1 and are respectively indicated by the

numbers

13, 15 and 17. For pu-rposes of clarity, switch 13 only (representative of each of the three) is shown in FIG. 2. Each switch has a transverse switch arm or blade 21 extending inward of the triangular platform 3. Each arm 21 is mounted upon one of the rotary insulators 9for angular opening movements in a horizontal plane according Ito the darts a, b and c. Dotted line switch-open positions of the arms 21 `are shown at the pointed ends of the darts. Line terminals or conductors 26 are in conductive relation to the respective arms 21. The lines are shown at A, B and C, these also being conductors.

Each switch arm 21 has an end 23 for reception when the switch is closed in a conductive spring-clip jaw 19. Details of such a jaw are obtainable from said Patent 2,786,121. When an arm 21 swings in the direction of one of the darts a, b or c, its respective end 23 sweeps out of the respective jaw 19. Conversely, when the

respective switch

13, 15 or 17 is closed in the direction against its respective dart, the end 23 of the respective arm 21 is again received in the respective jaw 19.

Each jaw 19 swings in a horizontal plane, as suggested by the darts d, e and f in FIG. l, and for the purpose is mounted for rotation about a vertical axis in a rotary bearing 25 (FIGS. 1, 2 and 3). Each bearing includes a. stop arrangement for limiting the closed-switch position of its respective jaw 19 such as shown by the solid lines in FIG. l, and each also includes a detent adapted to hold the jaws 19 in approximately the open dotted-line positions shown in FIG. l when the respective switches are open. Further details of such stop and detent arrangements are unnecessary herein, inasmuch as such are disclosed in Patent 2,786,121. Each rotary bearing 25 is mounted upon a fixed conductive plate 27, further reference to which will be made below. Thus the jaws 19 and plate 17 may be referred to as common contact means for the blades 21.

Each rotary insulator construction 9 is provided at its base with a crank arm 29. On each platform 3 are located three independent bearings 31 for three independently rotary shafts 32 respectively carrying driving cranks 33. rI'hese cranks 33 are linked with the respective cranks 29 of the

switches

13, 15 and 17 by connecting rods or

links

35, 37 and 39. The connecting

rods

35, 37, 39 are pivoted at opposite ends to the respective cranks. Thus by swinging the driving cranks 33 from the respective shafts 32, the

respective switches

13, 15 and 17 may be opened and closed as suggested by their dottedand solid-line positions shown in FIG. 1. Stops 28, engaged by lugs 30 on the arms 29, determine the closed positions of switches I3, 15 and 17 respectively (see, for example, FIG. 2). The shafts 32 extend Vertically through similar bearings 31 and carry similar cranks 33 on the additional (usually two) structures such as shown in FIGS. l and 2 and mounted below them. The shafts 32 are provided with suitable operating handles (not shown) near their lower ends adjacent the pole 1. Therefore, an operator at ground level near pole 1 may independently operate a gang of switches such as 13; or a gang of switches such as 15; or a gang such as 17. The usual construction involves a gang of three each for a three-phase electrical system.

Referring again to the fixed plate 27 (FIG. 2), it is supported upon a fixed insulator 41, rigidly supported 4 the triangular platform 3. This plate 27 also supports a vacuum-break load switch indicated generally by the numeral 45 and better shown in particular in FIG. 5, an example of which is sold by the Jennings Radio Corporation of San Jose, California, under the designation R9G. Such a switch is, in general, constituted by an air-evacuated sealed insulating (glass, for example) enclosure or envelope 47, It has hermetically sealed insulating ends 49 and 51. The lower portion of the enclosure 47 is extended upward as an inside open cup or dam 53, adapted to catch arc-ejected conductive material and to form a long surface-current leakage path between terminals. These conductive parts of switch 45 are, first, a lower hermetically sealed xed copper electrode 55, tungsten-tipped as shown at 57, extending up within the insulating end 51 of the switch and, second, an upper but downwardly extending movable electrode numbered 61, also tungstentipped, as shown at 63. The fixed electrode 55 has an outside conductive part 59. An outside wire terminal 62 is attached to the lower part 59 of electrode 55, which is connected to the conductive plate 27 by wire 56. The movable electrode 61 is provided at its upper end with an interior arc shield for shielding a flexible, collapsible and extensible metal sealing bellows 67, which at its lower end is hermetically sealed to the electrode 61 and at its upper portion is hermetically sealed to the switch end 49. An arc shield 64 is also attached to the lower electrode 55.

Above the arc shield 65 and extending through the bellows 67 is a conductive extension shank or rod 69 of the electrode 61. This is slidable in an insulating bearingforming portion 71 of the end 49. Insulating

parts

49 and 71 are attached to a second fixed plate 73, which is supported upon the plate 27 by means of spacing pillars 75. The conductive shank 69 at its upper end is attached by threads to a cup 77, having a threaded cap 79 and containing a seated conductive compression spring 81. This spring is in conductive contact with a lower flange 83 of an upper conductive plunger 85. Clamped to the plunger 85 is a conductive wire terminal 87. The plunger 85 extends slidably through a tubular bushing 89, which is threaded through a fixed plate 91 and maintained in position by a lock nut 93. The plate 91 is supported in spaced relation above the plate 73 by spacing pillars 95. The bushing 89 is also threaded at its upper end to receive a shoulder-forming staked nut 97.

The outside of bushing 39, above plate 91, functions as a journal for

bearings

99 and 101 of swinging conductive arms or

levers

103 and 105, respectively (FIG. l2). Lever 103 is single-armed, whereas lever 105 constitutes a bell

crank having arms

107 and 109. Bell crank 105, on its arm 107, carries a wire terminal 111 and arm 103 carries a similar wire terminal 113. Terminals 37 and 111 are connected by a wire 115.

Terminals

87 and 113 are connected by a wire 117.

Terminals

87 and 59 are joined by a wire connection 119, wherein is located a high-resistance element 121 on the order, for example, of 50,000 ohms for a switch designed to interrupt 200 amps at 7,200 volts. Thus the resistance 121 is connected in parallel with the

electrodes

55 and 61. The resistance 121 is not needed in some cases. Terminal 59 also has line wire 56 connected therewith, leading to a point 125 in a circuit such as shown in FIG. 13 and to be described in detail below.

As shown in FIG. 12, the

levers

103 and 105 are kinematically interconnected by means of a linkage numbered 127 in general. This is composed of a plate 129, pivoted at 131 on a journal 133 extending from the plate 91. Plate 129 is pinned at 135 to a link 137, which in turn is pinned at 139 to the arm 105. Plate 129 is also pinned 0 at 141 to a link 143, which in turn is pinned at 145 to the arm 103. The plate 129 also carries a journal 147 which forms a pin joint with a drag link 149, the latter being horizontally slotted, as shown at 151. From FIG. l2 it will be apparent that by rotating either lever 105 upon a bracket `43 on and near the geometric center of 75 or 103, the other will be rotated by reason of the kineanticlockwise motion (dart d).

FIG. 13 diagrammatically (and only so) exhibits the relationship of the contact elements of the invention applied to the circuit system to be served. Thus, for example, line wires A and C may be parts of a distribution system loop circuit, and line wire B a feeder circuit, it being desired to connect these three wires A, C and B in any combination between any two, or the three of them. The load switch 45 and its parallel-connected resistance 121 are connected between

points

59 and 87. Wire A has controlled branched connecting paths 179 and 131 to these points; wire C has controlled branched connecting

paths

183, 185 to the same points; and wire B has controlled branched connecting

paths

187, 189, also to these same points. The main switches 13, 15 and 17 are diagrammatically illustrated as being in the

conductive paths

189, 181 and 185, respectively and the transfer or

auxiliary switch devices

14, 16 and 18 in

conductive paths

187, 179, 183, respectively. The

paths

189, 181 and 185 include the load switch terminal 59.

Paths

187, 179 and 183 include the load switch terminal 87. The

paths

187, 189; 179, 181; and 183, 185 respectively form parallel connections, branches or legs between the terminals of the load-break means 45 and the conductors B, A and

C. Connections

189, 181, 185 may be referred to as main branches and 187, 179, 183 as auxiliary branches, respectively.

In the original positions of parts shown in FIGS. 1, 4 and 5, current flows from line A to feeder B through closed main air-

break switches

15 and 13, and current flows from line C to feeder B through closed main airbreak switches 17 and 13. Current may also flow between lines A and C via main air-

break switches

15 and 17.

Operation is as follows, starting with the position of parts as shown in FIGS. 1, 4, and 13, wherein both wires A and C (which may be assumed to be part of a distribution loop circuit) are electrically connected with wire B (which may be assumed to be part of a distribution feeder circuit). In this case, wire A may be supplying current to the feeder B through

closed switches

15 and 13; and wire C may also be feeding the wire through

closed switches

17 and 13. All of the main airbreak switches 13, 15, 17 and the load switch 45 are closed, the

transfer switch devices

14, 16 and 18 being open. Any one or more of the

switches

13, 15, 17 may be opened to the dotted-line positions shown in FiG.l by turning the appropriate shaft 32. It will also be understood that if additional assemblies such as shown in FIG. l are located above or below the plane of the drawing, then gangs of switches such as 13, or 15, or 17, will be gang operated. The number of switches thus ganged depends upon the number of phases of the circuit A, B, C requiring additional sections of the invention.

Assume, for example, that main switch 13 is to be opened. The appropriate shaft 32 is turned clockwise to draw link 35 to the dotted-line position indicated. This turns insulator 9 clockwise (dart a), thus rotating switch blade 21. The respective switch jaw 19 follows with an Before the end 23 of switch 13 leaves the respective jaw 19, hook 24 engages the arm 109 to close the transfer device 14. Upon subsequent motion, the end 23 or" switch 13 leaves the respective jaw 19 and switch 13 therefore opens. The parts are then in the position shown in FIGS. 8 and 9. The action swings arms 107 and 1&3 (arm 107 being part of the bell crank 105, of which arm 109 is an element) and arm 103 becomes driven by the linkage 127.

During the interval of motion of arm 109 from the position shown in FIG. 4 to the position shown in FIG. 8, the load switch 45 remains closed under action of the conductive compression spring 81, which during this internal is variably compressed from the FIG. 7 position. The spring 81 reacts between the shank 69 (which presses electrode 61 against electrode 55) and plunger 85 (which was initially prevented from freely rising because of the contact between the ends of the toggle links 163 and 165 angled to the left against the stop-forming crossbar 154-) (FIG. 5), as explained above.

When the parts are in the positions shown in FIGS. 8 and 9, the main switch 13 is open and the transfer switch 14 is closed. Then the ilow of current from line A to line B is through closed main switch 15, load switch 45 and closed auxiliary transfer switch 14. Current from line C to line B ows through closed main switch 17, load switch 4S and transfer switch 14. The lost motion between slot 151 and the knee joint pin 167 has been taken up.

Upon subsequent arm movement from the position of parts shown in FIGS. 8 and 9 to the position shown in FIGS. 10 and ll, the hook 24 of switch 13 rides out to the end but not 0H." of the arm 109, further turning it. This has the effect, through the linkage 127 and drag link 149, of iirst straightening out the toggle links 163 and 165, during which event the toggle pushes down the plunger 85, compressing spring 81 temporarily to increase the load on the

contacts

57 and 63 of the load switch 45 in their closed condition. This prepares them for subsequent snap-acting opening movement.

As the toggle linkage moves across its critical straightline position of

links

163, 165 and breaks toward the right (compare FIGS. 9 and 11), the plunger 85 is drawn up rapidly and shoulder 83 strikes cap 79, thus with snap action separating the

electrodes

61 and 55 of the load switch 45, as illustrated in FIGS. l0 and 1l.

It will thus be seen that the load switch 45 opens before opening of the transfer device 14. During this operation, return spring 169 (FIG. 10) has been stretched and after hook 24 of switch 13 leaves arm 109, the spring contracts to return the

arms

109, 107, 103 to their initial positions shown in FIG. 1. In so doing, the linkage 127 returns the drag link 149 from the position shown in FIG. 1l through the position shown in FIG. 9 to that shown in FIG. 5. This resets the toggle linkage to the FIG. 5 initial position and the load switch 45 to its closed position, ready for a subsequent operation in connection with the operation of any of the

switches

13, 15, 17. Before such a subsequent operation, as regards nowopen switch 13, the latter must be reclosed, which is accomplished simply by swinging it from the dotted-line position shown in FIG. 1 to the solid-line position. Its end 23 re-enters the respective jaw 19, thus returning it to the solid-line position. Reclosing is accomplished by turning the appropriate shaft 32 controlling movement of the link 35, which is connected to the crank 29 of switch 13. In the reclosure process, the hook end 24 of switch 13 slides under the arm 109 to position the hook ready for the next operation.

The other two switch assemblies constituted by main switch 15 with transfer switch 16, and main switch 17 with transfer switch 18, operate in like manner when manually actuated, and further elaboration will be unnecessary. It will be noted that the blades 21 of

main switches

13 and 15 in opening operations turn clockwise, whereas the blade 21 of switch 17 during its opening operations moves anticlockwise. The similar rotation of the

switches

13 and 15 during opening, and the reverse rotation of switch 17 during opening, explain why

levers

109, 109 may be formed as integral parts of the bell crank 105, the third lever 103 being separately pivoted and interconnected with bell crank by the linkage 127. Thus the lever 103 on the one hand, and the bell crank 105 on the other hand, are constrained for opposite but coordinate movement by the linkage 127.

ri`he purpose of the resistance 121, which forms a shunt connection across the

contacts

57 and 63 of the load switch 45, is to absorb high-voltage transients that under some line conditions may occur upon the rapid opening of the load switch. The resistance suppresses and shortens the period of arcing across these

contacts

57, 63 as the switch 4S opens. It will be seen from FIGS. 9 and l that the transfer device 14 will open shortly after the time that the load switch 45' opens, and that undue. continuation of such transient currents might damage the transfer device 14. The insertion of the resistance 121 assures that the switch 45 will have completely performed its opening action prior to the time that the transfer switch 14 opens. The small amount of current that flows through the resistance 121 after the switch 45 has opened can be readily controlled by opening of the transfer switch 14 without damaging the latter. It will be understood that in some cases, wherein high-voltage transients are not eX- pected, the resistance 121 may be omitted. The resistance consumes no substantial current under closed conditions of load switch 45, being in shunt relation.

The various advantages of the invention above referred to are evident, an important one being that open air-break switches of the class concerned are adapted for loadbreaking functions as distinguished from the functions of merely breaking line charging, leakage and transformer exciting currents, this being the result of the introduction into the arrangement of a load switch which had loadbreaking capacity.

Although, as heretofore, multiple main open air-break switches are involved in each phase of the circuit, only one load switch is employed to serve all of them in their respective switch-opening and -closing operations. The load switch `45 is operative under load-breaking conditions in connection with the circuit-disconnecting operations of any one of the

switches

13, 15, 17 as they function. Thus the load switch 45 functions for load-breaking purposes each time that any one of the

switches

13, 15, 17 is operated, the load switch returning to its closed position, ready for load-opening functions in connection with any one of the

switches

13, 15, 17 when closed or reclosed. As a result, the cost of the apparatus is considerably reduced because only one of its costliest parts (i.e., the load switch 45) is required to serve several of the open air-break switches. The result is that the eld of application of the gang operated open air-break switch construction is considerably enlarged.

The air-break switching structures as shown, employing horizontally swinging side-break switches, are of considerable merit because of the low head room required for safe switching, and the ability to mount them upon `a single pole, thus sav-ing right-of-way costs.

Finally, the switch is reliable and rugged, adapted for a long life. It will be understood that suitable weatherprotective hoods and the like may -be used for various parts, but these are not shown because they form no part of the invention per se.

In FIG. 14 is shown an alternative construction, illustrating how the invention may be applied in a case in which only two switches such as 15 land 17 might be required between lines A, C and B. In this case, like numerals designate identical parts, whereas like numerals which `are primed indicate parts that yhavel identical functions but are differently proportioned. As to the latter, it will be seen from FIG. 14 ythat triangular platform 3 does not require las great an extension by reason of the elimination of switch 13. Links 37' and 39 are shorter than their counterparts in the FIG. 1 form. The bell crank 105 has the same conducting arm 1i7 serving switch 15, but the other `conducting arm 109 of the bell crank 105 has been removed, not being required.

The circuit diagram for the FIG. 14 form of the invention is shown in FIG. l5, wherein like numerals designate like parts. It will be seen that this diagram is the same as that shown in FiG. 13, except that the parts and connections relating to

switches

13 and 14 have been omitted, the feeder line B being connected directly to point 59 via conductive plate 27 to which line B is attached, nather than being connected to that point through any switches such as 13 or 14 as in FIG. 13. It will be understood that FIG. 14 shows only the switch gear required for one 10 operating phase, `and that additional operating phases may be mounted on the pole 1 above or below the parts shown for gang operation from the shafts 32.

Operation of the FIGS. 14 and 15 form of the invention will be obvious from the above. The functional difference between the form of the invention sho-wn in FIGS. 14 and 15, and that shown in FIGS. l and 13, is that in the former case feed to the feeder line B cannot be interrupted Without interrupting the circuit between lines A and C, whereas in the latter case this is possible. Thus in the case of FIGS. 1 and 13, although switch 13 may be open, switches 15 and 17 may be closed to maintain connection between the lines A and C. This is not possible in the case of the form shown in FIGS. 14 and 15.

While the described vacuum-break type of switch is suitable as the load switch, it will be understood that other load type switches may be substituted, as for eX- ample an oil-filled load switch or the like which valso excludes air. l

in view of the above, it will be seen that the several objects of the invention Iare achieved and other Iadvantageous results attained.

As various changes could be made lin the `above con structions without departing from the scope of the invention, it is intended that all matter contained in the above description lor shown in the accompanying drawings shall be interpreted `as `illustrative land not in a limiting sense.

We claim:

l. Sectionalizing switch gear for selectively connecting two electric lines with each other and with a third electric line, comprising a normally closed load switch having opposite terminals, three air-break switch means each of which comprises a main switch `and a functionally connected .auxiliary transfer switch, said main `and transfer switches being connected in parallel between a respective line and opposite sides of said load switch, all of the main switches being connected to one side and yall of the transfer switches to the other side of said load switch, means adapted independently to operate the main and transfer switches sequentially in the respective air-break switch means temporarily to close the respective transfer switch, open the respective main switch and finally reopen ythe respective transfer switch, means connecting said independent operating means with the load switch adapted to disconnect the load whenever one of said transfer switches is temporarily closed, and means adapted independently to return the load switch to closed position `after it has opened, said independent means for operating the respective main and transfer switches being also adapted :to return them to ini-tial positions wherein the respective main switch is closed and the respective transfer switch is in its initial open position.

2. Sectionalizing switch gear for connecting two electric lines with a third electric line, comprising a load switch having opposite terminals to one of which said last-named line is connected, two air-break switch means each of which comprises a main switch and a transfer switch connected in parallel between opposite sides of said load switch and a respective one of said two lines, both of the lmain switches being connected to one side of the load switch and both of the transfer switches to the other side of .the load switch, separate means adapted to operate the respective main and transfer switches to open the main switches from normally closed positions, then close temporarily the respective transfer switches from normally open positions `and then to reopen the respective transfer switch, means responsive to said operation `adapted to open the load whenever one yof said transfer switches is temporarily closed, and means adapted independently to return the load switch to reclosed position after it has opened, said independent means for operating the respective main .and transfer switches being adapted to be individually `operated to return the same to initial posi-tion 1l. wherein the respective rnain switch is `closed and the respective transfer switch is reopened at its initial position.

3. Sectionalizing switch gear comprising7 a vacuumbreak load switch having opposite terminals, at least three electric lines, air-break switch means connected to each line, each air-break switch means having parallel connections 'from its respective line to opposite sides of said air-break switch means, each air-break switch means being constituted by a normally closed main switch located in one of its parallel connections and having an auxiliary transfer switch in the other one of its parallel connections, independent means adapted by a continuous movement sequentially to operate each air-break switch means temporarily to close its respective transfer switch, open its respective main switch and then to open again its respective transfer switch, and means operatively connecting each air-break switch means with said load switch adapted to open the load switch during the interval that the respective transfer switch is closed.

4. Sectionalizing switch gear made according to claim 3, wherein said means operatively connecting each airbreak switch means with the load switch includes a snapacting device for rapidly opening the load switch when it is operated and a resistance connected across the load yswitch adapted to suppress any arcs that might otherwise carry current to an open transfer switch because of rapid opening of the load switch.

5. Sectionalizing switch gear made according to claim 3, including means adapted automatically to return said load switch to closed position after sequential reopening of each respective transfer switch.

6. Sectionalizing switch gear made according to claim 3, including biasing means adapted to reclose the load switch after the transfer switch has opened.

7. Sectionalizing switch gear made according to claim 6, including means thereafter independently to return said air-break switch means to their initial positions, wherein the respective main switches are closed and the respective transfer switches are open.

8. Sectionalizing switch gear comprising a normally closed vacuum load switch having opposite terminals, opening means therefor, means biasing said load switch toward closed position, line terminals, at least two airbreak switch means each consisting of a normally closed main switch and a normally open auxiliary transfer switch connected in parallel between the respective line terminals and opposite sides of said load switch, operative connections lbetween the main and transfer switches in each air-break switch means adapted for independently sequentially temporarily closing the respective transfer switch, opening the main switch and then reopening the transfer switch, operative means between said operative connections adapted respectively to open to load switch against its biasing means during the interval that the respective transfer switch is closed and adapted to release the load switch for biased reclosure, operating means for biased return to closed position of the load switch after the respective transfer switch has opened, each of said air-break switch means being independently returnable to an initial normally closed position of its main switch after the load switch has reclosed.

9. Sectionalizing switch gear comprising triangularly related rotatable insulators, each carrying a movable switch blade, an intermediately located fixed insulator, a conductive support on said fixed insulator carrying switch jaws which are adapted respectively to be engaged and disengaged by the respective switch blades, a load switch carried upon linsulation upon said support and having one electrode in conductive connection therewith, said load switch having a second electrode movable between switch closed and open positions, transfer switches having first movable conductive elements carried by but insulated from said support, said first elements being in conductive relation to said movable electrode, said transfer switches having Vsecond movable conductive elements carried by said switch blades respectively for lost-motion engagement therewith, and lost-motion driving means connecting the first elements of the respective transfer switches with said movable electrode of the load switch to move the latter into closed and open positions relative to the xed electrode, the arrangement being such that lost motion is taken up between the two elements of the respective transfer switches to close them respectively as the respective switch blades are moved toward positions out of their respective jaws, said two elements of each transfer switches being separable thereafter, said `first elements of the transfer switches being adapted through their said respective driving connections to move the movable electrode of the load switch to open position during the interval that the elements of the transfer switches are connected and after the main switch blades have left their respective jaws.

10. Sectionalizing switch gear made according to claim 9, wherein each of said driving means comprises a snapacting overcentering mechanism.

1l. Sectionalizing switch gear made according to claim 10, wherein said mechanism is a toggle linkage biased to buckle in one direction to held said electrodes together and in the reverse direction to separate them.

12. Sectionalizing switch gear made according to claim 11, wherein the toggle linkage is connected with said movable electrode through a 10st-motion resilient connection.

13. Sectionalizing switch gear comprising triangularly related insulators, two of which carry switch blades and are rotatable, being located on a line, and the third one of which is xed and located between the rotatable insulators and to one side of said line, a conductive support on said fixed insulator carrying switch jaws which are adapted respectively to be engaged and disengaged by said respective switch blades, an insulated load switch carried upon said third insulator and having one electrode in conductive connection with said support, said load switch having a second electrode movable between switchclosed and -open positions, transfer switches having first movable conductive elements carried by but insulated from said support, said first elements being in conductive relation to said movable electrode, said transfer switches having second movable conductive elements carried by said switch blades respectively for lost-motion engagement therewith, and lost-motion driving means connecting the first elements of the respect-ive transfer switches with said movable electrode of the load switch to move the latter into closed and open positions relative to the fixed electrode, the arrangement being such that lost motion is taken up between the -two elements of the respective transfer switches to close them respectively as the respective switch blades are moved toward positions out of their respective jaws, said two elements of each transfer swi-tch being separable thereafter, said first elements of the transfer switches being adapted through their said respective driving connections 'to move the movable electrode of the load switch to open position during the interval that said first elements are connected and after the main switch blades have left their respective jaws.

14. Sectionalizing switch gear made according to claim 13, wherein said driving means comprises a snap-acting overcentering mechanism.

15. Sectionalizing switch gear made according to claim 14, where-in said mechanism is a toggle linkage biased to buckle in one direction to hold said electrodes together and in the reverse direction to separate them.

16. Sectionalizing switch gear made according to claim 15, wherein the toggle linkage is connected with said movable electrode `through a lost-motion resilient connection.

17. Sectionalizing switch gear comprising a normally closed load switch having first and second terminals, drive means movable from an initial to a final position for opening the load switch from an initial closed position,

means adapted automatically to return said drive means and the load switch to their initial positions after each operation of the drive means, at least two circuits each having first and second legs parallel-connected to said first and second 'terminals respectively, a pair of main and transfer yswitches in said first and second legs respectively of each circuit, means f-or independently operating said main switches, interconnecting means between the members of each pair of main and transfer switches adapted to close the transfer switch of the pair before its respective main switch opcns and thereater to reopen the respective transfer switch, and interconnecting means between each transfer switch and said drive means for opening the load switch, adapted to coordinate operation of each transfer switch with that of the load switch to open the load switch after each closure lof a transfer switch, the load switch and drive means therefor automatically returning thereafter to their initial closed positions.

18. Sectionalizing switch gear made according to claim 17, wherein the load and transfer switches are of the airbreak type and said load switch is of the vacuum-break type.

19. Sectionalizing switch gear made according to claim 18, wherein said drive means for the load switch includes a snap-acting device operative rapidly to open the load switch.

20. Sectionalizing switch gear according to claim 19, including an arc-suppressing shunt connecting said load switch terminals adapted to suppress any arcs associated with the rapid opening of the load switch.

2l. Sectionalizing switch gear comprising a normally closed load switch having first and lsecond terminals, drive means movable from an initial to a final position for opening the load switch from an -initial closed position, means adapted automatically to return said drive means and the load switch to their initial positions after each operation of the drive means, three circui-ts each having first and second legs parallel-connected to said first and second terminals respectively, -a pair of main and transfer switches in said first and second legs respectively of each circuit, means for independently operating said main switches, interconnecting means between the members of each pair of main and transfer switches adapted to close the transfer switch of the pair before its respective main switch opens vand thereafter to open the respective transfer switch, and inter-connecting means between each transfor switch and said drive means for opening the load switch, adapted to coordinate operation of each transfer switch with that of the load switch to open the load switch after each closure of a transfer switch, the load switch and drive means therefor automatically returning thereafter to their initial closed positions.

22. Sectionalizing switch gear for selectively connecting and disconnecting first and second electric wireS with each other and with a third wire, comprising a normally closed load switch means having rst and second terminals, a first pair of parallel eie^trical conductor means extending from the first wire to said terminals, a second pair of parallel electrical conductor means extending from the second wire to said terminals, main switches located respectively in those of said conductor means which join with said first terminal, transfer switches located respectively in those of said conductor means which join with said second terminal, said third wire being connected with said first terminal, and independently controlled sequential operating means connected between the main switch and the transfer switch in each pair of parallel conductor means adapted respectively to open a main switch in the respective connection after preliminarily closing the respective transfer switch therein and thereafter reopening the transfer switch, and means operable in response to actuation of any of said sequential operating means adapted to open said load switch means after the respective trans- 14 fer switch has closed and before reopening of the respective transfer switch.

23. Sectionalizing switch gear according to claim 22, including means adapted automatically to return the load switch to an initial closed position after each opening operation thereof.

24. Sectionalizing switch gear according to claim 23, wherein said means adapted to open the load switch comprises a snap-acting mechanism.

25. Sectionalizing switch gear according to claim 24, wherein said snap-acting mechanism is constituted by a spring-opening toggle device.

26. Sectionalizing switch gear for selectively connecting and disconnecting first, second and third electric wires, comprising a normally closed load switch having first and second terminals, a first pair of parallel-connected electrical conductor means extending from the first wire to said terminals, a second pair of parallelconnected electrical conductor means extending from the second wire to said terminals, a third pair of parallelconnected electrical conductor means extending from the third wire to said terminals, three main switches located respectively in those of said conductor means which join with said first terminal, three transfer switches located respectively in those of said conductor means which join with said second terminal, and independently controlled sequential operating means respectively connected between the main Switch and the transfer switch in each of the three parallel-connected conductor means adapted sequentially to open the main switch therein after preliminarily closing the respective transfer switch therein and thereafter reopening the transfer- Switch, means operable in response to any of said sequential operating means adapted to open said load switch before the opening of the respective transfer switch, and means adapted automatically to return the load switch to an initial closed position after each opening operation thereof.

27. Switch gear for selectively connecting and disconnecting first and second electric conductors with each other and with a third conductor, comprising a load switch means having first and second terminals, a first pair of parallel electrical conducting means extending from the first conductor to said terminals, a second pair of parallel conducting means extending from the second conductor to said terminals, main switches located respectively in those of said conducting means which join with the rst terminal, auxiliary switches located respectively in those of said conducting means which join with said second terminal, said third conductor being connected with said first terminal, and operating means associated with each pair of parallel conducting means adapted to open a main switch in the respective connection while the respective auxiliary switch therein is closed and thereafter opening the auxiliary switch, and means operable in response to actuation of any of said operating means adapted to open said load switch means when the respective auxiliary switch is closed and before opening of the respective auxiliary switch.

28. Switch gear for selectively connecting and disconnecting first and second electric conductors with each other and with a third conductor, comprising a load switch means having first and Second terminals, a first pair of parallel electrical conducting means extending from the first conductor to said terminals, a second pair of parallel conducting means extending from the second conductor to said terminals, main switches located respectively in those of said conducting means which join with the first terminal, auxiliary switches located to control the flow of current through said conducting means which join with said second terminal, said third conductor being connected with said first terminal, and operating means associated with each pair of parallel conducting means adapted to open a main switch in the respective connection while the re- `spective auxiliary switch therein is closed, means adapted to open said auxiliary switch thereafter, means operable in response to actuation of any of said operating means adapted to open said load switch means when the respective auxiliary switch is closed and before reopening of the respective auxiliary switch, and then to open the respective auxiliary switch, and means adapted to close the load switch means while the respective auxiliary switch is open.

References Cited in the le of this patent UNITED STATES PATENTS McKenney Dec. 18, Flurscheim Dec. 31, Palme et al. May 3, Lindell July 7, IForwald Nov. 3, Schwager Oct. 22, Schwager June 10, Curtis et al. Aug. 26, Hoffmann July 7,