US2456502A

US2456502A - Double throw switch

Info

Publication number: US2456502A
Application number: US769909A
Authority: US
Inventors: Howard W Graybill
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1947-08-21
Filing date: 1947-08-21
Publication date: 1948-12-14
Anticipated expiration: 1965-12-14
Also published as: GB643953A; FR970597A; BE484365A

Description

Dec. 14, 1948. w. lL 2,456,502

DOUBVLE nmow swn'cn 2 Sheets -Sheat 2 Filed Aug. 21, 1947 INVENTOR florvaru hlmy/ll.

I BY (31/3 Patented Dec. 14, 1948 DOUBLE 'rnnow swrrcn Howard W. Graybill, Honey Brook, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation 01 Pennsylvania Application August 21, 1947, Serial No. 769,909

6 Claims.

This invention relates to double throw electric switches generally, and especially to high voltage disconnect switches of this type.

Switches of the disconnect type which are mounted outdoors often give trouble by reason of the switchoperating mechanism becoming fouled as by ice; dirt or corrosion. Single throw switches designed to avoid these difllculties are known wherein the mechanism is completely enclosed as in H. L. Rawlins Patent No. 2,363,360,

tween insulators

4 and 6, and is secured to base 2 in any desired manner.

issued November 21, 1944, on Circuit interrupters,

to the same assignee of this invention. Heretofore, however, the additional mechanism required for double throw switches, especially where such switches are .of the high contact pressure type wherein the switch blade has a compound movement in diiIerent directions, has made it impossible to adequately protect the mechanisms of these switches.

Accordingly, one object of this invention is to provide novel operating mechanism for disconnect switch blades having compound movement and of the double throw type.

Another object of this invention is to provide a novel simplified actuating mechanism for double throw disconnect switches which is adequately protected from the atmosphere.

Another object of this inventionis to provide a novel cam mechanism for double throw disconnect switches of the type described.

These and other objects of this invention will become more apparent upon consideration of the following detailed description of a preferred embodiment thereof, when taken in connection with the attached drawings, in which:

Figure 1 is a top plan view of a switch constructed in accordance with this invention;

Fig. 2 is an enlarged longitudinal section view taken substantially centrally through the supported end of the switch blade shown in Fig. 1.

Fig. 3 is an end view of the supported end of the switch blade with a part 01' the supporting housing broken away, and I Fig. 4 is a profile of the cam track employed i the switch shown in Figs. 1 to 3,

In the embodiment of this invention illustrated on the drawings, it will be seen from Fig. 1 that Insulator 4 has mounted on the outer end thereof a terminal plate l2, as by bolts l6, and this terminal plate supports contact jaws 14 which may be either integral with or formed separately from terminal plate- I 2 and secured thereto by a bolt l6. Similarly, insulator 6 has secured to the outer end thereof a terminal plate I8, as by bolts 22, and is provided with contact jaws like the contact jaws. l4.

Stationary insulator 8 has secured to the outer end thereof one end of a supporting bracket 24, as by bolts 26, with the outer end of the bracket being formed to provide a flat terminal pad 28.

, The inner end of supporting bracket 24 extends to the outer end of a fourth insulator 30 adapted to be rotatably mounted at its other end in supporting base 2. The outer end of insulator 30 is provided with a cap 32 which may be secured thereto in any desired manner as by bolts 33, and this cap has secured to the projecting central portion thereof an actuating crank 34, as by screws 36'. As illustrated in Fig. 2, the juncture of cap 32 and crank 34 is located in the region of the inner end of supporting bracket 24, and is grooved to form with an opposed groove formed in an opening in this end of bracket 24, a raceway -for ball bearings 38 so that the outer end of rotatable insulator 30 is rotatably supported by bracket 24 from stationary insulator 8.

The movable switch blade is adapted to be supported on bracket 24 in a manner to be described,

and this blade comprises a tubular blade member housing 42, for a purpose to be described. Housthe switch is adapted to be supported on a base 2 which may be of channel iorm, with one stationary insulator 4 mounted atone end of base 2, and a second stationary insulator G mounted at the'other end of base 2. A third stationary insulator 8 is adapted to be mounted at the outer end of a short base member I! which extends laterally from base 2 substantially midway being 42 may also have spaced integral extensions 52 extending in a direction along blade 40 and being joined at their outer ends by an integral tor.

supported on bracket 24 by a pair of spaced'lugs 60 and 82, which may be formed integral with housing 42-, and are apertured for receiving pivot bolts 66 passing through the apertures in these lugs and through apertures provided in spaced supporting arms 64 'securedon or integral with bracket 24. I 1

At a point opposite wall 44 of housing 42, there is provided an-opening, 68 in the housing whichis adjacent to and intersects the axis oipi'votal movement or the blade and housing on pivot bolts 66. Opening, 68 in housing 42 is adapted to receive a substantially spherical portion of brank 34, with the crank further including an 'angularly extended crank portion 12 adapted to crank roller l4 enters the intermediate portion or cam track is to cause supporting housing 42 and blade 40 to move about pivot bolts 68 until I an upright position'oi the blade is reached" when crank roller 14 will have reached thev intersection of cam trackways 18 and 89. At this medial position or the switch blade,;crank roller 14 has a choice. upon continued .rotation of insulator 30' in the same direction, or returning along trackbe disposed within housing 42. Crank portion 12' is provided to its outer end with a cam follower roller 14 mounted on crank portion 12 as by a It will be noted that theouter end of blade 40 is provided with a fiat tip 86 of a width slightly in excess of the spacing between the contact Jaws I4 and 20, so that when blade tip 86 is located transversely of either pair or contact jaws it will be in high pressure contact engagement therewith. .If desired, inserts 88 may be providedon' opposite sides of blade tip 88 of an are resistant material having good electrical conducting qualities, to form the actual contact of the blade with the contact jaw.

Fig. 4 illustratesin

profile cam tracks

18 and 80, with the angle A indicating the angle at which each point on each cam track is located relative to the horizontal plane as viewed in Figs l, 2

and 3, with the switch in the closed position illustrated in these figures. The angle B of Fig. 4 indicates the angular rotation of insulator 30 required to position crank roller 14 at each point along the cam tracks. Itwill be observed from Figs. 3 and 4 that cam tracks 18 and all meet at one point which corresponds to a position of'the blade relative to the axis of pivot bolts 66 substantially ,midway between

insulators

4 and 6, or at an angle of about 90 from'that shown in Figs. 1, 2 and3u In theo peration of-the switch described above and illustrated on the drawings, it will be observed that if it is desired to operate the switch from the closed circuit position shown in Figs. 1, 2 and 3 wherein it engages contact jaws 20, it is necessary to rotate insulator 30 in a counterclockwise direction as viewed in Fig. 1. opening movement of rotatable insulator 30 re-' sults in crankroller 14 travelling along a straight portion of cam track 18 for a distance correspond- 1 ing to almost 20 rotation of the rotatable insula- During this initial rotation of insulator 30,

no pivotal movement of blade 40 occurs on the axis of pivot bolts 68 inasmuch as this initial portion of cam track 18 is horizontal. However. inasmuch as an intermediate portion of angular way 15 -or oi. entering trackway 80. In order that such continued rotation ot insulator in the same direction shall cause switch blade 48 to move into engagement with contact j'aws l4.

itis necessary that crank roller 14 enter trackway 80, and this is the purpose of projection 82 of the housing, for at such medial position the proiection 82 will be received in notch 84 provided on crank 34. It will be apparent, accordingly,

that continued rotation oi insulator'30 in the same direction will cause blade housingifl and the blade to be kicked over toward contact jaws M by projection 42, thus causing crank roller '14 to enter trackwayw-tfl. Itwill bepapparent that after passing the medial position, crank roller will continue along'trackway 80 until i it reaches'th'e flat end thereof corresponding to a position of switch blade 42 where the blade tip 86 is received between contact jaws l4, but at an inclination thereto, whereupon continued travel of crank roller 14 along the'fla't end portion of trackway 80 causes rotation'ot blade/-42 about its longitudinal axis to a position whereblade tip as is positioned traversely of contact jaws l4 and into pressure engagement therewith. If it is desired to actuate switchblade 40 back into engagement with contactjaws 20, it is merely necessary to rotateinsulator 30 in the opposite direction, whereupon the opposite of the movements described above will occur.

It isapparent from the description given above of one embodiment of this invention, that the .invention includes the provision of a novel switch mechanism especially adapted for a switch-of the type where a switch blade is; mounted for rotation substantially about its axis'into and out or high pressure engagement with'line-contacts, and is also mounted for pivotal movement toward and i away from such contactsywhich, mechanismis adapted to actuate such av switch of the double j Initial crank part 12 is received in fork in of the switch blade, the blade will be rotated during this initial movement of insulator 30 about the longitudinal axis of the blade to position the flat blade tip sure contact with the jaws. Upon continued rotation of insulator 30 in the same direction,

throw type. while at a l times itpo sitively correlates the angular posltio'n'otthefiat blade tip relative to the longitudinal axis. of the blade and I with the angular position orthe blade about its pivot axis on'which it moves into and out of en gagement with the line contaacts. Moreover, this mechanism'is or the type which is substantially entirely closed, and thus adequately pro- 7 tested from the atmosphere.

' Having described a preferred embodiment in this invention in, ccordance, with -theflpatent statutes, it is desired that the invention be not limited to this particular structure, inasmuch as it will be apparent, particularly to persons skilled in the art,- that 'rnanychanges and modifications may be made in this structurewithout departing from the'broad spirit'and scope or this invention.

According y, it isdesired that the inventionbe interpreted as'broadly as possible and that it be :limited only as required by the prior I claim as my inventioni 1. In a double throw sfwitch, ispaced line. con- 'tacts, a switchblademonnted on a support intermediate said contacts for pivotal movement of the blade into and out of engagement with .either oi? said contacts, rotatable operating means for said blade located adjacent said blade support, cam track and follower means associated with said blade and operating means, respectively, said cam track means comprising similar displaced portions joined at a location which substantially corresponds to the medial position of said blade and being cooperable with said follower means for causing movement of said blade at each side of a medial position, respectively, and means separate from said cam means for switchingsaid follower means to one or the other of said cam track portions dependent upon the direction of rotation of said operating means.

2. In a double throw switch, spaced line contacts, a switch blade having a housing portion at one end mounted on a support intermediate said contacts for pivotal movement of the blade into and out of engagement with either of said contacts, said housing portion having an opening adjacent the pivot axis of said blade, rotatable operating means for said blade located adjacent said blade support and extending into said housing portion through said opening, cam track and follower means associated with an inner wall of said housing portion and a part of said operating means within said portion, respectively, said cam track means comprising similar displaced portions joined at a location which substantially corresponds to the medial position of said blade and being cooperable with said follower means for causing movement of said blade at each side of a medial position, respectively, and means separate from said cam means but outside of said housing portion for switching said follower means to one or the other of said cam track portions dependent upon the direction of rotation of said operating means.

3. In a double throw switch, spaced line contacts, a switch blade mounted for rotation about a longitudinal axis on a support which in turn is mounted intermediate said contacts for pivotal movement of the blade into and out of engagement with either of said contacts, rotatable operating means for said blade located adjacent said blade support, cam track and follower means associated with said support and operating means, respectively, said cam track means comprising similar displaced portions joined at a location which substantially corresponds to the medial position of said blade and being cooperable with said follower means for causing movement of said blade at each side of a medial position, respectively, and means separate from said cam means directly connecting. said blade and operating means for rotating said blade about said longitudinal axis upon operation of said operating means in predetermined relation to pivotal movement thereof.

4. In a double throw switch, 'spaced line contacts, a switch blade mounted for rotation about a longitudinal axis in a housing which in turn is pivotally mounted on a support intermediate said contacts for pivotal movement of the blade into and out of engagement with either of said contacts, said housing having an opening adjacent the pivot axis of said blade, rotatable operating means for said blade located adjacent said blade support and extending into said housing through said opening, cam track and follower ment of said blade at each side of a medial position, respectively, and means separate from said cam means directly connecting said blade and operating means for rotating said blade about said longitudinal axis upon operation of said operating means in predetermined relation to pivotal movement thereof. a

5. In a double throw switch, spaced-line contacts, a switch blade mounted on a support intermediate said contacts for pivotal movement of the blade into and out of engagement with either of said contacts, rotatable operating means for said blade located adjacent said blade support, cam track and follower means associated with said blade and operating means, respectively, said cam track means comprising similar displaced portions joined at a location which substantially corresponds to the medial position of said blade and being cooperable with said follower means for causing movement of said blade at each side of a medial position, respectively, and means separate from said cam means for switching said follower means to one or the other of said cam track portions dependent upon the direction of rotation of said operating means, comprising parts associated with said blade and operating means, respectively, which are positioned to intermesh at said medial position of said blade.

6. In a double throw switch, spaced line contacts, a switch blade mounted for rotationabout a longitudinal axis in a housing which in turn is pivotally mounted on a support intermediate said contacts for pivotal. movement of the blade into and out of engagement with either of said contacts, said housing having an opening adjacent the pivot axis of said blade, rotatable operating means for said blade located adjacent said blade support and extending into said housing through said opening, cam track and follower means associated with an inner wall of said housing and a part of said operating means within said housing, respectively, said cam track means comprising similar displaced portions joined at a location which substantially corresponds to the medial position of said blade and being cooperable with said follower means for causing movement of said blade at each side' of a medial position, respectively, means separate from said cam means directly connecting said blade and operating means for rotating said blade about said longitudinal axis upon operation of said operating means in predetermined relation to pivotal movement thereof, and means separate from said cam means and located exteriorly of said housing for switching said follower means to one or the other of No references cited.