US1872298A - Switch mechanism - Google Patents

Description

A. H. KEHOE ET AL Aug. 16, 1932.

' swTcH MEcHANlsM Filed Nov. 25. 1927 4 vSheets-Sweet Zaag/z.-

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Aug, 16, 1932. A. H. KEHOE ET AL 1,872,298

SWITCH MECHANISM Filed Nov. 25, 1927 4 sheets-sheet 2 Aug. 16, 1932. A, H, KEHOE ET AL' 1,872,298

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SWI'IICH MEGHANISM Filed Nov. 25. 4 sheets-sheet v4 @www Patented Aug. 16, 1932 UNITED STATES PATENT OFFICE ARTHUR KEHOE, F RUTHERFORD, NEW JERSEY, AND LEE W. MCCULLOUGH, OF NEW YORK, N. Y., ASSIGNORS, BY MESNE ASSIGNMENTS, TO WESTINGHKOUSE ELEC- Tmc a MANUFACTURING comrANY, A

CORPORATION 0F PENNSYLVANIA SWITCH MECHANISM Application led November 23, 1927. Serial No. 235,163.

The present invention relates to improvements in switch mechanism and aims to proification when read in connection with the accompanying drawings and the points of f novelty will be defined with particularity in f an enlarged scale;

ythe appended claims.

F ig.y 11 is a somewhat diagrammatic side elevation with parts broken away illustrating an embodiment of our invention applied to the disconnect contacts of an oil truck switch, the parts being shown in closed circuit position;

Fig. 2 is a similar view disconnected; t

Fig. 3 is a section on line 3- showing the parts of Fig. 1 on Fig. 4 is a view in open circuit position of the parts shown in Fig. 3;

Fig. 5 is a sectional elevation showing the application of our invention to a disconnect switch;

Fig. Gis a front elevation of the switch shown in F ig. 5;

Fig. 7 is an enlarged view of a gasket'shown in the other figures;

Fig. 8 is an enlarged view illustrating mechanism for covering certain fixed contacts when the truck switch. is disconnectedv therefrom;

Fig. 9 is a front elevation of part of the mechanism shown in Fig. k8; certain parts being omitted in the interest of clearness.

Referring first to Figs. l and 2, 10 represents a truck type switch as a whole. This includes a conventional type of oil circuit breaker 12, the circuit of which can be made and broken by manipulation of the handle 14. The truck switch is supported on rollers 16 which travel on a track 18. The construction of the oil circuit breaker 12 is of conventional or standard design and forms no part of the present invention, and therefore, will only be briefly described and illustrated. The circuit breaker member 12 coacts with coninsulators 3() secured to a fixed panel duotors 20 which are electrically connected with contact members 22 and 24. The latter are adapted to be electrically connected with terminal contacts 26 and 2S when the truck switch l0 is moved to the position of Fig. 1, the latter terminal contacts being carried by S2 suitablysupported by the structure 38. The contacts 26 and 28 are connected to bus bars 34 and 36, respectively, leading to the outgoing conductors 34 and 36. The lead sheaths of these conductors are connected to a ground wire 42 by short conductors 43 as shown.

A ground switch member 38 is pivoted at 40 to the fixed switch structure and is Con-v nected to a cable 42 leading to the ground. This member can be swung about its pivot by manipulation of the handle 41 when the truck is in open position of Fig. 2making circuit from contact 28 through conductor 42 to ground. The member 38 is provided with an arcuate portion 44 which lies in a path of a rod 46 carried by the truck switch. 10 so that when the ground switch member is in the position of Fig. 2, the truck switch cannot be moved to bring its contacts 22 and 24 into engagement with the contacts 26 and 28. On the other hand, when they truck switch is in the closed circuit position of Fig. l, the rod 46 lies in the ath of movement of the ground switch mem er 44 and, th erefore7 prevents establishing a circuitfrom contact 28 to ground when the circuit is closed through the contacts 22-26, 24-28. In other words, there is sort of an interlock arranged to vent movement of the truck switch into closed position while the ground switch is closed and also to prevent closing the circuit to ground while the truck switch is in closed circuit position. t

An important feature of the invention resides in the construction of the contacts and in the arangement forsupporting them and housing them and in the means for forming a substantially air or gas-tight sealfaround the coacting contact members. The construction of the two contacts 22 and 24 is substantially identical as is also the construction of the contacts 26 and 28. A description of one coacting set of contacts will, therefore,

pre-

sul'llce for both. As best shown in Figs. 3 and 4, contact 24 comprises a pair ot plates 50 having their ends iared outwardly as at 52. These plates are secured to spring conductors 54 by means of rivets 56. Laminated springs 58 serve to press the plates 50 toward one another. The parts are secured by means of a bolt 60 to the end ot a conductor bar 62 which passes through the insulator' bodies 64 and 66. The latter is secured to the front wall 68 ot the truck switch by means ot bolts 70. rifhe insulator 66 is recessed at to receive a boss 74 formed on the rear of the insulator 64. A collar 76 is secured to the bar 62 and bears against the inner surface oi' the hollow insulator 64, and the parts 64 and 66 are clamped in position by a nut 78 threaded on the end of the conductor bar 62. The conductor 20 ot the truck switch is suitably connected to the bar 62 by means ot a clamp nut 80.

The insulator 64 is ot shell-like form being provided with an annular ilange 82 having an enlargement 84 forming a shoulder. In front ot this shoul der, the diameter of the insulator is reduced and between the shoulder and the ends there is formed an annular bead 86.

A gasket 88 formed of rubber or similar flexible or resilient material is stretched or tensioned over the annular bead 86 and the heel portion 90 thereot` is seated against the shoulder 84. rlhe heel portion ot the gasket 88 is relatively heavier than the fore part thereof. The fore part of this gasket is in the form of an elongated flexible extension 92.

T he contact member 28 which coacts with the contact 24 is similarly surrounded by a chambered insulator 94 having a shoulder 96 against which is seated a gasket 98 ot substanti all 'i the same form as the gasket 88, said gasket being stretched or tensioned over an annular rib 100 formed on the insulator 94. llVhen the contacts 24 and 28 are in closed circuit position, the gaskets 88 and 98 are pressed against one another and orm a substantially gas or air-tight seal around the switch contacts and the same may be said to be hermetically sealed within the chamber formed by the cavities formed in the insulators 64 and 94.

lVhile we have shown two cooperating `gaskets one compressed against the other, it is to be understood that, it' desired, the seal may be secured by providing one gasket adapted to be compressed against an adjacent structure.

The insulator 94 is attached by means of suitable bolts 102 to an insulator 104 which in turn is secured to the panel 82 of the stationary part of the switch structure by means of bolts 106. The contact terminal 28 is formed of two pieces of rolled copper bar as indicated in Fig. 3 which are suitably secured to one another along the line 28. This contact is formed with a shank 108 which extends at a right angle through the insulator and the exterior of the insulator is provvided with a hub 110 adapted to form an anchorage or gripping point for the insulating tape 112 which is wrapped around the bus bar 11,4 and connecting plates 116 used to attach the bus bar to the shank 108. It is advantageous to provide such an anchorage for the insulating tape so that the whole structure can be thoroughly insulated without leaving breaks or gaps at the joints. In switching equipment handling heavy currents or high potentials, faults occasionally occur on both insulated and uninsulated equipment due to the presence of conducting gases, moisture, fumes and accidental contact by animals or other conductors. The gaskets described etlectively prevent short circuiting tlashovers by conducting gases and the wrapped or taped joint in which the tape overlaps the hub as described makes an effective gas-tight seal to prevent lashovers or short circuits. The invention is not limited to use in connection with truck switches and it is to be understood that it is applicable to various other circuit connections where itis desired to close or hermetically seal the space surrounding live or electrically charged contacts. For example, we have shown the invention in Fig. 5 applied to a disconnect switch comprising a switch blade 118 encased in a body of insulation 120 and formed with substantially cylindrical chambered portions 122 and 124 carrying gaskets 88 substantially the same as those above described. The disconnect switch shown is provided with a hinge portion 126 pivoted at 128 to'a fitting 130. The blade 118 co-operates with contact jaws 132 and 134 which are adapted when the switch is closed to project into chambered portions 122 and 124. The contact jaws are surrounded with insulator bodies 136 and 138, the forward portions of which are fitted with flexible gaskets 98 adapted to be compressed against the gaskets 88 so as to form a seal about the coacting connections. Thedisconnect switch shown is provided with a lock pawl 140 arranged to engage a latch 142 as shown.

From the foregoing it is apparent that our improved arrangement effectively insulates live parts of separable switch contacts such `for example as air break switches or disconnect contacts in the closed position and provides means for preventing short circuits between adjacent phases or short circuits to ground by conducting gases, moisture, fumes or accidental contacts with various conductors. The seal described also excludes air, fumes or moisture which tends to corrode contacts. r1`he flexible gaskets employed are detachable and can be conveniently replaced at regular intervals Without the use lof special tools when the switching equipment is undergoing routine tests or overhauling.

Fig. 7 shows that the forward extension 92 of the gasket is thinner than the base or rear part thereof and is also offset from the base. This shape gives a degree of `flexibility which enables the meeting portions of the two gaskets, asy in Fig. 3, to bend under slight compression and to adjust themselves closely against each other at allpoints in the circumference. In this way, a tightercontact is secured than could be obtained by abutting rings pressed together merely under pressure. In Figs. 8 and 9 we have illustrated mechanism for sealing the stationary contact members 26 and 28 against moisture conducting gases fumes or accidentalcontact bypersons during the interval when the truck switch 1() is withdrawn. The mechanism, as will hereinafter appear, is so arranged that the sealing of Contact members 26 and 28 is automatical ly effected when the truck switch is moved to its non-operative position, for example, that Shown in Fig. 2. On the other hand,rwhen the truck switch 10 is moved into the operative position of Fig. 1, the covers for contacts 26 and 28 are caused to automatically Aopen so as to allow the co-operating j aw members 22 and 24 carried by the truck switch t0 properly coact with their mating Contact members. The mechanism is also so coordinated with the ground switch member 44 that when said member is in the open position of Fig. 1, the contact member 28 will be covered and, conversely, when the member 44 is in the closed position of Fig. 2, the coverL for contact member 28 will be yautomatically opened. Both the upper and lower covers 144 and 146 for contacts 26 and 28 are actuated in response to in and out movements of the truck switch 10. Also, the operation yof the cover for the lower contact 28 is actuated in response to movements of the ground switch member 44. Illustration of this mechanism has beeny omitted from the diagrammatic Figures 1 and 2 in the interest of clearness and said mechanism is illustrated on an enlarged scale in Figs. 8 and 9.

As shown in Fig. 9, lthere are three upper covers 144 and threelower covers 146. This is the arrangement which will be followed in y poly-phase circuits, there usually being a separate pair of switchijaws 26 and 28 for each of the three phases. In the description thus far, merely one contact of the triple arrangement has been referred to. It is understood, of course, that in three phase work I there will be three contacts 26 and three contacts 28, and the corresponding parts of the movable truck switch will also be arranged in triplicate. A description of one set is sufficient, of course, for the'three or other number' of duplicate parts.

Each of the upper covers 144 is carried on an arm 148. secured to an insulated shaft 150 which at each end carriesa pulley 152. f The lower covers 146 are similarly carried on arms 154` secured to the lower insulated shaft 156 which also carries pulleys 158. Secured at 160 to each pulley 152 is a band 162 Which'is tacts. The plate 17 0 is adapted to be moved vertically when the truck switch 10 is moved y `to closed position. Anysuitable means may be provided for accomplishing this and We have illustrated by way ofeXample` av roller 176 secured to a suitable bracket carried bythe plate 170, said roller being arranged to coact witha cam 178 carriedby the truck switch 10 so that when the truck switch moves into closed position, the cam will lift the plate 170 a suflicient distancevto move the pin 168 from the full line position to the dotted line position shown in Fig. 8. Such movement of the pin 168 will rotate the pulleys 152 and 158 counter-clockwise so as to move the covers 144 from thefull line positions to the dotted line positions indicated. In effecting this movement, the left end of the slot 164 in the band 162 engages the pin 166. When the truck switchl() is withdrawn the upward force on plate 170 is released and the pin 168 occupies the position shown in full lines in Fig. 8 and the covers 144 and 146 fall into the position indicated in full lines and thus automatically cover and seal the stationary contacts 26 and'28. `Each cover, it bein understood, carries a in detail in Fig. 7.

The lower covers 146 are also arranged to be automatically opened when the ground switch member 44 is moved to the closed position sh'own'in Fig. 2. This operation is effected by means of a link 180 pivoted at 182 to an arm secured to the shaft 40. At its upper end link 180 is `provided with an elongated slot to permit loss of motion and the upper end of this slot engages apin 184 carried by anarm of the pulley 158. The slot in link 180 permits the pin 184 to move counter-clockwise without imparting motion to the ground inter lockmember 44. However, when the inter-lock member 44 is rocked' pin 166 secured to the pulley rides 'freely through the slot 164'in the band 162 and the pulley merely slips relatively to said band 162. I

While we have described quite specifically the details of the embodiment of the invention illustrated, it is not to be construed'thati ioo we are limited thereto since various modifications and substitution of equivalents may be made by those skilled in the art without departing from the invention as defined in the appended claims.

What we claim is l. The combination with a truck switch and coact-ing separable disconnect switch contacts, of a resilient member adapted to enclose the contacts and thus protect them against high voltage flashovers, when they are in closed. position.

2. The combination with an oil switch and lcoacting separable disconnect switch contacts, of' chambered insulators enclosing at least part of each respective contact and means secured to at least one of said insulators adapted to substantially hermetically seal the contacts within said chambered insulators and thus isolate them from conducting gases which are apt to cause high voltage flashovers.

3. The combination with coacting separable switch contacts of coacting resilient gaskets, whose walls are tapered in cross section, said gaskets being adapted to be flexed inwardly to secure a face to face engagement over a wide annular area so as to form a substantially arc proof enclosure for said contacts when the latter are in closed position.

4. The combination with coacting separa ble switch contacts, of coacting resilient gaskets having relatively heavy heel portions and lighter flexible extensions adapted to be flexed to form an arc proof enclosure for said contacts when the latter are in closed position.

5. In switching mechanism of the movable truck type, a fixed contact having a housing of rigid insulating material, a movable contact having a similar housing and flexible gaskets secured to said housings arranged to isolate and protect said contacts electrically when the switch is inl closed position against disturbances which would inevitably occur if a conducting medium should touch contacts energized at high transmission voltages.

o. In switching mechanism of the character described, a fixed contact having a housing -of insulating material, a movable contact having a. similar housing and rubber gaskets whose walls are tapered in cross section so as to form flexible extensions adapted to guard said contacts within said housings against high voltage arcs when the switch isclosed.

7. Inswitching mechanism of the character described, coactingA contact members and means for forming an enclosure with an adequate high voltage insulating covering for said contacts including a gasket. having a relatively heavy heel and a thinner flexible extension adapted to be compressed against an adjaeentvmember.

8.' In switchingmechanism ofthe. character described, coacting contact members and means forming an adequate arc-repelling insulating enclosure for said contacts including a housing of insulating material having an annular flange and a gaskettensioned around K said flange and having a flexible extension tapered in cross section adapted to be compressed against an adjacent member.

9. A switch terminal comprising a bar having its contact portion surrounded by a body of insulating material and a resilient gasket of non-uniform cross section secured to said body having a flexible portion extending beyond the extremity of said cont-act.

l0. In switch mechanism a fixed structure supporting an insulator body having a chambered portion within which is located a contact, a movable truck switch having a. contact adapted to coact with the first named contact, and flexible means for making a gas tight arcproof closure around said contacts when the truck switch is moved to engage said contacts with one another.

ll. In switch mechanism a fixed structure supporting an insulator body having a chambered portion within which is located a contact, a movable truck switch having a contact adapted to coact with the first named contact, and a gasket having a heavy heel and a lighter flexible extension adapted to be com pressed to form a gas-tight arc-proof closure around said contacts when the truck switch is moved to close engage said contacts with one another.

1Q. In switch mechanism of the character described includiiw a fixed contact, a movable contact carried by a truck switch, a resilient gasket surrounding the fixed contact, a movable coveringmounted in juxtaposition to the fixed contact and means for automatically moving said cover to or from gastight engagement with said gasket upon movement of said truck switch relatively to said fixed contact.

13. In switch mechanism of the. character described, a fixed contact having a gasket with a flexible extension surrounding the same, a truck switch carrying a contact adapted to coact with said fixed contact and a movable cover arranged to engage said gasket when the truck switch contact is disengaged from the fixed Contact and means for automatically disengaging the cover from said gasket upon closing movement of said truck switch.

14. The combination with coacting separable switch contacts of coacting gasketsof resilient material having relatively thick heel portions and thinner forward portions disposed at an angle thereto.

In witness whereof` lwe have hereunto signed our names.

ARTHUR H. KEHOE. LEE W. MCCULLOUGH.

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