US2613291A - Auxiliary contact construction for load interrupter switches - Google Patents

Description

Oct. 7, 1952 J. J. KOJIS 2,613,291

AUXILIARY CONTACT CONSTRUCTION FOR LOAD INTERRUPTER SWITCHES Filed April 26, 1950 2 SHEETS-SHEET l .15 '7 [6/6455 [6/6455 7Z2 65 26 I Q INIfENTOR. Jo/zrz Jfio L6) Oct. 7, 1952 .1. J. KOJIS 2,613,291

AUXILIARY CONTACT CONSTRUCTION FOR LOAD INTERRUPTER SWITCHES Filed April 26, 1950 2 SHEETS-SHEET 2' INVENTOR.

Patented Oct. 7, 1952 AUIHLIARY CONTACT CONSTRUCTION FOR LOAD INTERRUPTER SWITCHES John J. Kojis, Chicago, Ill., assignor to S & C

Electric Company, Chicago, 111., a corporation' of Delaware Application April 26, 1950, Serial No. 158,246

14 Claims.

This invention relates, generally, to high voltage electric power load interrupter switches and it has particular relation to the construction of auxiliary contacts employed for maintaining a circuit through the load interrupter while it is interrupting the current flow in the circuit after the main contacts have been opened. However, the application of the present invention is not so limited. This invention constitutes an improvement over the switch construction disclosed in application Serial No. 41,597, filed July 30,

1948, and assigned to the assignee of' this application.

Among the objects of this invention are: To overcome improper functioning of the auxiliary contacts resulting from the formation of ice on the engageable contact surfaces; to construct the stationary auxiliary contact so that if ice appears thereon, it will be in the form of icicles which can be broken or pushed off readily on engagement by the movable auxiliary contact; to provide the stationary auxiliary contacts with a plurality of depending projections on which the icicles readily form; to construct the movable auxiliary contact so that it will break or push off the icicles without its being permanently deformed while providing sufficient resiliency therein to maintain the required contact pressure with the aforesaid projections on the stationary auxiliary contact member; to employ a bow configuration for the movable auxiliary contact; and to reinforce the bow shaped auxiliary movable contact so that it is pretensioned and rigidified and one bow end is not moved upwardly when the opposite bow end is depressed on initial engagement with the first of said projections.

Other objects of this invention will, in part, be obvious. and in part appear hereinafter.

This invention is disclosed in the embodiment thereof shown in the accompanying drawings and it comprises the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of this invention, reference can be had to the following detailed description, taken together with the accompanying drawings, in which:

Figure l is a view, in side elevation, of a high voltage load interrupter type of disconnecting switch in which the present invention is embodied;

Figure 2 is a detail sectional view, at an enlarged scale, taken generally along the line 2-2 of Figure 1;

Figure 3 is a view similar to Figure 2 but showing the relative positions of the stationary and movable auxiliary contact members during the initial movement of the latter to the switch open position, the main contact members shown in Figure 3 bein omitted; and

Figure 4 is a bottom plan view of the housing shown in Figures 2 and 3 which constitutes the stationary auxiliary contact member, the position of the movable auxiliary contact member relative to ice forming projections thereon being shown by broken lines.

Referring now particularly to Figure 1 of the drawings it will be observed that the reference character It designates, generally, a load interrupter type of switch intended for operation in a circuit energized at a voltage of 34.5 kv. However, it will be understood that the present invention can be employed in conjunction with switches operating at higher or lowervoltages, the specified voltages being for illustrative purposes only.

The switch lfl includes a channel base H havin stationary insulators H2 at its ends extending' upwardly. The insulators l2 carry terminal brackets 13 which are secured by bolts 14 to the upper ends of the insulators I2. Terminal pads 15, formed integrally with the brackets [3, provide for connection to thevcircuit in accordance with conventional practice. Midway between the stationary insulators I2 is a rotatable insulator IS. The insulator i6 is rotatable in a bearing construction I1, carried by the channel base ll about a vertical axis. An operating arm 18 is provided for rotating the insulator l6 either individually or for gang operation with two other similar switches [0 making up a three phase installation.

At its upper end the insulator l6 has a clamp by bolts 26 to an angle bracket 21 of good con ducting; material such as copper which, in turn, is secured by tap bolts 28 tothe terminal bracket the blade tip 23;

I3 associated therewith. It will be understood that the main contact arm 24, which constitutes an extension at each end of the switch blade 22, and the associated stationary main contact member 25 are arranged to carry the load current when .theswitch L is inthe closedposition as illustratedf-in Figures 1 and 2. The; main contact arm 24 and stationary main contact member 25 may be constructed as disclosed in the copending application above referred to or in accordance with copending applioa tion 'serial No. 159,025 filed April 29, 1950, nowi'Patent' No. 2,567,606 dated Sept. 11, 1951. Also it will be. understood that other constructions ofmaincontacts can be employed in practicing-the present invention. Accordingly, a detailed description of the particular main contact arm Zlan'd sta-- tionary main contact member 25 will not beset forth herein.

It is not intended that an arc will be drawn b'etweenith'e main contact arm 24 and the stationary main contact member 25 when the switch is opened and they are separated. In order to interrupt'the circuit'in a satisfactory and efficient manner a load interrupter device, indicated generally'at 3|, is employed. The details of construction of the load interrupter device 3| are set forth in application Serial No. 41,597, filed June 30, 1948. Alternatively the load interrupter switch construction disclosed in United States Patent No. 2,351,826, issued June 20, 1944, and assignedto'the assignee of this application, also 0311"]38 usedi Sincetheparticular details of construction of the load interrupter device 3| form no part of the present invention, the same will not be set'forth herein. Also it will be understoodthat'other types of load interrupter devices canbe-employed inpracticing this invention.

"ITIE'IO'ad interrupter-device 3| may be secured bybolts 32 to'a-n angle bracket 33 of good conducting material such as copper. The angle bracket 33 is secured by suitable bolts (not shown) to the terminal bracket l3. There are two load interrupter devices 3| employed, one being, located on each of the terminal brackets |3"at each' end of" the switch blade 22. The angle bracket 33 is bolted, as indicated, to one terminal-34 of theload' interrupter device 3|. This terminal is separated by an insulator 35 from a terminal housing, shown generally at 35, which may be formed of cast red brass. The terminal housing 35' is insulated by the insulator 35 from the terminal 34. Provision is made, as will be described presently, for maintaining contact engagement with the terminal housing 35 prior to disengagement of the main contact arm 24 from the stationarymaincontact member 25 and during the period after separation while the load interrupter device 3-| is-carrying the entire load current and is interrupting the same. When so employed the terminal housing 36 functions as astationary contact member and is so referred to in the claims.

On the underside of the terminal housing 35 there is a bifurcated operating arm that is indicated, generally, in Figure 4 at 31. The operating arm 3T has branches 38 and 39 and is arranged to control the operation of the mechanism within the load interrupter device 3 I. The operating arm 31 of the load interrupter device 3-l'is'arranged to bemoved byan operator, shown generally at 4|, which forms an integral part of As shown in Figure 2, the operator-di includesflanges |2 and 43- that are arranged tocooperate respectively with the branches 38 and 39 for operating the load .interrupter device 3| to and from the closed circult position. A tail piece M constituting an extension of the flange 42 and formed integrally with the blade tip 23 cooperates with the branch 38 to lockthe load interrupter device, 3| in the closed'position. For .a more complete understanding of the manner in which the load interrupter device 3| is controlled and operated, reference can be had to the copending applicatiornSeriaLNo. 41,5971, filed July 30, 1948, mentioned. he-reinbefore.

It.is intended that the load interrupter switch J0 shall bis-mounted in the position illustrated in Figure. 1.. Asset forth hereinbefore the switch blade 22 swings in a horizontal plane about" the ventical.axisofltherotatable insulator H5 in moving from. and to the switch closed position. The plane ofswinging movement of the switch blade 22 is below the terminal housings 35 carried by the terminal brackets 3. In prior constructions .a'dependingconti'nuous flange has been provided on theundarsid'e of each terminal housing 35 to permit-contact engagcmenttherewith while the main'contact-arm 24 is separating from the stationary main contact member "25 andyduring the period that the load interrupted device 3| is: operating toopen' the circuit. Under certain 10mg and sleet conditions, a layer of ice may for-mon such a depending flange and it constitutes an insulator which prevents the desired contact. engagement with the housing 36 during the period just referred to.

With a view to overcoming such a difficulty, instead of employing a continuous flange with which contact engagement can. be made, the .terminal housing 36' isaprovided on. its underside with zin'tegrally f ormerk wedge. shaped projections 511.551, .52. and 53'. For illustrative purposes it is. pointed out that each of the wedge shaped projections 5'ili'through 53 may be about inch long; inch.wide..and arranged to taper to a width of. 5inch. attheir lower. ends. As illustratediin Figure 4',s.the"w.edge shaped projections .5jfljthrouglm filarespaced. apartalong an arc, illustratedziby' the broken line 54', whose center is the verticaLasrisoi' rotation of the rotatable insulator 18..

Under: icing on sleet conditions icicles, shown at.-55-,miFfig11re;:2; may: form on the lower ends .ofutheuprojections; 51] through 53. Because of the:sp-aces55,-I.5'|, and 58Ibetween the projections 59--5i|;. 5|f--'5.2, -and .52--53, respectively, the ice willrformzas-ioicles 55.; as described, rather than aszrasingle: sheet of ice as is the case when a continuous fiangexis employed instead of the spaced projections; It-is .unlikely that thesleet or icingconditionswill be so severe as to fill the spaces 5-6:,.'5'|"and- 58. Thus. theice is formed in discreetlbodies or-iciclesr55 which may be pushed ofior brokenoffreadily leaving the lower ends ofnthe: projections 50., 5|, 5'2 and 53 free of ice and-capable oi-jbeingcontacted readily to comple.te.:th.e.circuit through the load interrupter device 3| as is requiredfor proper operation.

In accordance with this invention, contactengagement. withthe projections 50, 5|, 52 and 53 is obtained through theuse of a bow shaped resilient: contact. member that is indicated generally atfill. Thesbowshaped contact memberfifl is formed preferably of good conducting resilient material such as Phosphor bronze. For illustrative purposes it ispointed out that it'may initially have alength of 13 inches, a, width of one inch and a thickness of .032 inch. Its

intermediate portion'Gl is arranged tohave sliding'contact engagement with the lower-ends of the wedge shaped projections 59, 5|, 52 and 53. As illustrated, the contact member 6t extends upwardly from the switch blade 22 at each end at rightangles thereto. Its bow ends 62 interconnect the intermediate contact portion 6| with straight end portions 53 that extend toward each other and have-curved end portions fi l which extend downwardly around opposite sides of the switch blade 22. The curved end portions 55 are clamped to the switch blade 22 by bolts 65.

Not only does the bow shaped contact member have to provide a current carrying path between the terminal housing 36 and the switch blade 22 but also it must function to break or push-off the icicles from the lower ends of the wedge shaped projections 50, 5|, 52 and 53, should they be present. Also it is desirable that the lower ends of these projections be engaged with a relatively high contact pressure in order to provide a low resistance current conducting path and to avoid external arcing. For this purpose the bow shaped member 50 is constructed, as described, and has a relatively initial high degree of resiliency. Prior to their being applied tothe switch blade 22 the end portions 63 and 64 occupy the position illustrated by the broken lines in Figure 2.

With a view to holding the bow shaped con- .3 tact member in the position shown by full lines in Figure 2 where it is prestressed and in order to rigidify the same and further to prevent one bow end 62 from being raised upwardly when the other how end 62 engages the first of the projections 50, 5|, 52, and 53, from either direction of movement, brace members 66 are employed and, as shown in Figure 2, are nested with the end portions 63 and 54 of the bow shaped contact member 60. Each brace member 66 is formed preferably of Phosphor bronze and initially each has a length of 3%.; inches. Each has a width of one inch, the same as the width of the bow shaped contact member as and a thickness of .064 inch. Each brace member 66 has a straight end portion 5'! which overlies the straight end portion 63 at each end of the bow shaped contact member 60. Also each brace member 66 has a curved end portion 68 which is interposed between the corresponding curved end portion 64 of the bow shaped contact member 65 and the surface of the switch blade 62. The bolts 65act to clamp the curved end portions 54 of the bow shaped contact member and the curved end portion 6% of the brace member 66 securely in position as shown in Figure 2.

When the switch blade 22 is swung toward the switch closed position, the main contact arm 24 starts to move out of engagement with the stationary main contact member 25. Before disengagement therebetween takes place, the bow shaped resilient contact member 50 engages the wedge shaped projection as as illustrated in Figure 3. In the event that an icicle 55 should have been formed on this projection, it is broken or pushed ofi as here illustrated. Likewise, as the switch blade 22 continues to move to the open position, icicles 55 on the succeeding projections 5|, 52, and 53 are broken or brushed off. Because of the presence of the brace member 66, the bow end 62 engaging the projection 58 is rigidified and possesses suflicient strength to break or brush off the icicle 55. In the absence of thebrace member 66, there would be a tendency for the other bow end 82 to rise when the 6 how end 62 engages the projection '50. However, the presence of the brace members 66 prevents this and, since two of them are used, such undesired movement of the bow ends 62 is prevented for either direction of movement of the switch blade 22. At the same time the intermediate contact portion 6| is thrust upwardly with a biasing action sufiicient to provide good contact engagement with the lower ends of the projections 50, 5|, 52, and 53.

In the drawings the projections 50, 5|, 52 and 53 are shown extending from the underside of the housing 36. Where the load interrupter device 3| is otherwise mounted, the housing 36 is modified so that projections, corresponding to the projections 50, 5|, 52, and 53, extend down wardly, as for example from the side 69 where it constitutes the underside of the housing 36.

Since certain further changes can be made in the foregoing construction and difierent embodiments of the invention can be made without departing from the spirit and scope thereof, it is intended that all matter shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is: v

1. A switch construction for outdoor mounting comprisingin combination, a stationary contact member having a plurality of depending projections on its underside on the lower ends of which icicles may form, a switch blade movable underneath said projections, a bow shaped resilient contact member extending from said switch blade for sequentially engaging the lower ends of said projections to make electrical contact ".therewith and to break on" any icicles formed thereon, the ends of said bow shaped contact member being secured to said switch blade, and brace means cooperating with said ends of said how shaped contact member to pretension and rigidity the same and prevent upward travel of one bow end when the opposite bow end is depressed on initial engagement with the first of said projections.

2. A switch construction for outdoor mounting comprising, in combination, a stationary contact member having a plurality of depending projections on its underside on the lower ends of which icicles may form, a switch blade movable underneath said projections, a bow shaped resilient contact member extending upwardly from said switch blade for sequentially engaging the lower ends of said projections to make electrical contact therewith and to break ofi any icicles formed thereon, the ends of said bow shaped contact member extending toward each other and being secured to said switch blade, and a pair of brace members nested with said ends of said bow shaped contact member and extending in opposite directions to pretension and rigidify the same and prevent upward travel of one bow end when the opposite bow end is depressed on initial engagement with the first of said projections.

3. A switch construction for outdoor mounting comprising, in combination, a stationary contact member having a plurality of depending projections on its underside offset from each other along a circular are on the lower ends of which icicles may form, a switch blade rotatable about.

the center of said are underneath said projections, a bow shaped resilient contact member extending from said switch blade for sequentially engaging the lower ends of said projections to make electrical, contact, therewith and to, break oilzany icicles. .tormedjthereon, the-ends ofsaid bowrshapedzcontact member being secured-tosaid switch: blade,,.andbrace means cooperating with said ends ofsaidbow shaped: contact member to pretension and rigidity, the same and prevent upward travel of one bow end when the opposite bowend is depressed on initial engagement with the first of saidprojections.

4. A switch construction for outdoor mounting comprising, in combination, a stationary contact member having a plurality of. depending; projections-on itsunderside offset from each other-along a circular are on the lowerrends of which icicles may form, a switch. blade rotatable about the center of said are in a plane underneath said projections, abow, shaped resilient contact member extending upwardly from, and: at right angles to. said, switch blade for sequentially engaging the IOWELEHdS of said: projections to make electrical contact therewith. and to break off any icicles formed thereon, the ends of said bow shaped contact member extending downwardly around the sides ofsaid switch blade and bein secured thereto, and apair of brace members nested with said ends of said bow shaped contact member and extendingin opposite directions to pretension and rigidify the same and prevent upward, travel of one bowend when the opposite bow end is depressed on initialengagement with the first of said projections.

5. A switch construction for outdoor mounting comprising, in combination, a stationary contact member having a plurality of depending projections on, its underside offset from each other along a circular are on the lower ends of which icicles may form, a switch blade rotatable about the. center of said are in a plane underneath said projections, a bow shaped resilient contact member extending upwardly from and at right angles to saidswitch blade for sequentially engaging the lower ends of said projections to make electrical contact therewith and to break off any icicles formed thereon, the ends of said how shaped contact member being secured to said switch blade, and a pair of, brace members nested with said ends of said bow shaped contact member and extending in opposite directions to pretension and rigidity the same andv prevent upward travel at one bow end when the opposite bow end is depressed on initial engagement with the first of said projections.

6; A switchconstruction for outdoor mounting comprising, in combination, a stationary contact member having a plurality of depending projections on its-underside offset from each other along a'circular are on the lower ends of which icicles may form, a switch blade rotatable about the center of said are underneath said projections, a bow shaped resilient contact member extending from said switch blade for sequentially engaging the lower ends of said projections to make electrical contact therewith and to break off any icicles formed thereon, the ends of said bow shaped contact member extending toward each other and downwardly around the sides of said switch blade and being secured thereto, and a pair ofbrace members nested with said ends of said bow shaped contact member and extending in opposite directions to pretension and rigidify the same and prevent upward travel of one bow end when the opposite bow end is depressed on initial engagement with the first of said projections. 7. A switch construction for outdoor mounting comprising, in combination, a stationary con.- tact member having a plurality of depending wedge shaped projections on its underside offset from each other along a circular arc on the lower ends of which icicles may form, a switch blade rotatable about the center of said are in a plane underneath said projections, a bow shaped resilient contact member extending upwardly from and at right angles to said switch blade for sequentiallyengaging the lower ends of said projections to make electrical contact therewith and to break off any icicles formed thereon, the ends of said bow shaped contact member extending toward each other and downwardly around the sides of said switch blade and being secured thereto, anda pair ofv brace members nested with said ends of said bow.- shaped contact member inside thereof around saidswitch blade and extending in oppositedirections to pretension said how shaped contact member and rigidity the same and prevent upward travel of one bow end whenthe opposite bow send .is depressed on initial engagementwith the first of said projections.

8. Ahigh voltage loadinterrupter switch construction comprising, in combination, .a switch blade rotatableabout a vertical axis, a stationary main contact, member arranged to be engaged and disengaged by said switch. blade, a load interrupter device connected to said main contact member for interrupting the currentfiow through said switch on separation of said switch blade from said main contact member, said load interrupter device including a housing disposed above the plane of rotation of said switch blade; and meansior interconnecting said switch, blade and said housing to maintain the circuit through said load interrupter device after said switch blade disengages said main. contact member. while said device is interrupting the current flow through said switch including ap-lurality of projections, depending from the underside of .said housing oirset from each other along an arc Whose center, is said vertical axis and on the lower ends of which icicles may form, a bow shaped resilient auxiliary contact. member ex, tending from said switch blade for sequentially engaging the lower ends of said projections to make electrical contact therewith for maintaining said circuit and to break off any icicles formed thereon, the ends of said bow shaped auxiliary contactvmember being secured to, said switch blade, and, brace means cooperating-with said endsof said'bow shaped auxiliary contact member to pretension and rigidity the sameand prevent upward travel of one bow end when the opposite bow end is depressed on initialengagement with the first of said projections.

9,, A high voltage load interrupter switch construction comprising, in combination, a switch blade rotatable about a vertical axis, a stationary main contact member arranged to be engaged and disengaged by said switch blade, a load interrupter device connected to said main contact member for interrupting the current flow through said switch on separation of said switch blade from said main contact member, said load interrupter device including a, housing disposed above the plane of rotation of said switch blade; and means forinterconnecting -said switch blade, and said housing to maintain the circuit through said load interrupter device after; said switch blade disengages said main, contactmember whilesaid device is interrupting the current flow through said, switch includinga plurality of, projections depending ,from, the underside of said housing oiiset from eachother. along an arc whose center is said vertical axis and on the lower ends of which icicles may form"; a bow shaped resilient auxiliary contact member extending upwardly from andat 'rightangles to said switch blade for sequentially engaging the lower ends of said projections to make electrical contact therewith for maintaining said circuit and to breakoff any icicles formed thereon, the ends of said bow shaped auxiliary contact member extending downwardly around the sides of said switch blade and being secured thereto, and a pair of brace members nested with said ends of said bow shaped auxiliary contact member and extending in opposite directions to pretensi-on and rigidify the same and prevent upward travel of one bow end when the opposite bow end is depressed on initial engagement with the first of said projections.

10. A high voltage load interrupter switch construction comprising, in combination, a switch blade rotatable about a vertical axis, a stationary main contact member arranged to be engaged and disengaged by said switch blade, a load interrupter device connected to said main contact member for interrupting the current flow through said switch on separation of said switch blade from said main contact member, said lead interrupter device including a housing disposed above the plane of rotation of said switch blade; and means for interconnecting said switch blade and said housing to maintain the circuit through said load interrupter device after said switch blade disengages said main contact member while said device is interrupting the current flow through said switch including a plurality of projections depending from the underside of said housing offset from each other along an arc whose center is said vertical axis and on the lower ends of which icicles may form, a bow shaped resilient auxiliary contact member extending upwardly from and at right angles to said switch blade for sequentially engaging the lower ends of said projections to make electrical contact therewith for maintaining said circuit and to break off any icicles formed thereon, the ends of said bow shaped auxiliary contact member being secured to said switch blade, and a pair of brace members nested with said ends of said bow shaped auxiliary contact member extending in opposite directions to pretension and rigidify the same and prevent upward travel of one bow end when the opposite bow end is depressed on initial engagement with the first of said projections.

11. A high voltage load interrupter switch construction comprising, in combination, a switch blade rotatable about a vertical axis, a stationary main contact member arranged to be engaged and disengaged by said switch blade, a load interrupter device connected to said main contact member for interrupting the current flow through said switch on separation of said switch blade from said main contact member, said load interrupter device including a housing disposed above the plane of rotation of said switch blade; and means for interconnecting said switch blade and said housing to maintain the circuit through said load interrupter device after said switch blade disengages said main contact member while said device is interrupting the current flow through said switch including a plurality of projections depending from the underside of said housing offset from each other along an arc whose center is said vertical axis and on the lower ends of which icicles may form, a bow shaped resilient auxiliary contact member extending from said switch blade for sequentially engaging the lower ends of; said projections to make electrical contact therewith for maintaining said circuit and to break off any icicles formed thereon, the ends of said bow shaped auxiliary contact member extending toward each other and downwardly aroundthe sides of said switch blade and being secured thereto, and a pair of brace members nested with said ends of said bow shaped auxiliary contact member and extending in opposite directions to pretension and rigidify the same and prevent upward travel of one bow end when the opposite bow end is depressedoninitial engagement withthe first of said projections.

12. A high voltage load interrupter switch construction, comprising, in combination, a switch blade rotatable about a vertical axis, a stationary main contact member arranged to be engaged and disengaged by said switch blade, a load interrupter device connected to said main contact member for interrupting the current flow through said switch on separation of said switch blade from said main contact member, said load I interrupter device including a housing disposed above the plane of rotation of said switch blade; and means for interconnecting said switch blade and said housing to maintain the circuit through said load interrupter device after said switch blade disengages said main contact member while said device is interrupting the current flow through said switch including a plurality of wedge shaped projections depending from the underside of said housing ofiset from each other along an arc whose center is said vertical axis and on the lower ends of which icicles may form, a bow shaped resilient auxiliary contact member extending upwardly from and at right angles to said switch blade for sequentially'engaging the lower ends of said projections to make electrical contact therewith for maintaining said circuit and to break off any icicles formed thereon, the ends of said how shaped auxiliary contact member extending toward each other and downwardly around the sides of said switch blade and being secured thereto, and a pair of brace members nested with said 'ends of said bow shaped auxiliary contact member inside thereof around said switch blade and extending in opposite directions to pretension said bow shaped auxiliary contact member and rigidity the same and prevent upward travel of one bow end when the opposite bow end is depressed on initial engagement with the first of said projections.

13. A switch construction for outdoor mounting comprising, in combination, a stationary contact member having a plurality of depending projections on its underside on the lower ends of which icicles may form, and a switch blade movable relative to said contact member for sequentially engaging the lower ends of said pro- 'jections to make electrical contact therewith and to break oii any icicles formed thereon.

14. A high voltage load interrupter switch construction comprising, in combination, a switch blade rotatable about a vertical axis, a stationary main contact member arranged to be engaged and disengaged by said switch blade, a load interrupter device connected to said main contact member for interrupting the current flow through said switch on separation of said switch blade from said main contact member, said load interrupter device including a housing disposed above the plane of rotation of said switch blade; and means for interconnecting said switch blade and said housing to maintain the circuit through said 11 lb'atl internipter' tfeifice after samswitch blade d'fsngdges' s'afd main comm member: While said device interrupting theilr'i'e'nt now through said switch including a plurality of projeetions depending from the underside-of said heu'sing Offset from each other along an are whose center is said vertical axis and on the lower ends of which icicles may form, and a contact member "carried by said *switch blade for sequentially engaging the lower ends of said projections to make electrical Contact therewith for maintaini'n'g' said circuit and to break bff anY'lbi'cles 1 2 REFERENCES CITED. The following references are of record in-the me of thi's patent:

UNITED STATES PATENTS Number Name Date -1 264,79? Honold Apr; 30, 1918 2,351,826 Lindell et a] June 20,1944

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