US1906505A - Switch - Google Patents

Description

May 2, 1933. A. ALSAKER 1,906,505

SWITCH Filed April 2.9, 1929 2 Sheets-Sheet 1 May Z, 1933.

A. ALSAKER SWITCH 2 Sheets-Sheet 2 Filed April 29, l1929 l-VI Patented May `2, 19.33y

UNITE-D vsTA-.'rfas PATENT OFFICEl A ALFRED ALsAxER, OF oIIICAGOi,"ILLINOIs, AssIGNoR fro rrIIE DELTAs'rAR ELECTRIC. COMPANY, or CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS f SWITCH Application Lled rApril 29;

This application ay continuation part of my copending application" Serial No. 237,678, tiled December 5',f1927,"andlthis invention relates to electric switches, more particularly to the` outdoor gang yoperated type such` as arecommonly employedforv power disconnect purposes.V While the invention is particularl applicable to this service, it is not intended to limit itto that use. v l

VSwitches of the present type areinfre-` quentlyoperated and after remaining closed for long periods yof time during which they are subjectedto ally :sorts of weather ,lconditions, there is a tendency for the` switch Vcontacts to stick together. Ice or sleet' may form on the contacts-if thecontacts'areeX-r, posed, thus rendering opening `of vthe switch rather difficult. `Unless special means is employed for.Y separating the contacts,`the

insulator stacksl supportingthe contacts may be subjected Vto excessively `high mechanical stresses. It is a particularobj'ect ofthe presenty invention toY provide .a simple switch mechanism vwherein the preliminary ice breaking movementof the switchicon-k tacts is obtained without inducing excessive mechanical stresses inthe insulators. y.

The present form of switch com rises two. su )porting insulators upon oneo `which a re atively long switch blade is Inountedrand upon theother of which, al relativelyr short switch contact is mounted.. 4Both insulators are rotatable and are mechanically in-` terconnected so that rotation of oneof the insulators produces ,rotation of the other. The blade engages the contact ywith a wiping movement thus forming a clean contacting surface between the blade. andits contact. Upon opening the switch `the blade and contact separate with a shearingmotion, and because of the relativelyl longlength of the blade and the relativelyshort,turning radius of the rotatable contact member, a great shearing force is 'generated which is suflicient to break the bind between the blade and the contact member whether this binding is caused by corrosion, orv byice or sleet. This great shearing force, is, of course, due to the fact that theblade and the contact 1929. sejriai N0.f35s,s93.

likewise whenthe switch is closed thesleet shield minimizes or prevents the formation.

of ice ybetween the switch blade and the contact. e

The sleet shield is, in the present embodiment of the invention, in the form of a plate overhanging theswitch contact and secured thereto. By this arrangement the inertia of the moving mass is'considerably reduced.)

e The attainment ofv the above and further objects `ofthe invention willlbe apparent from' the following specification taken in conjunction with the accompanying draw`r ings forming a part thereof.

In the drawings: 1

Fig. 1 is a side elevational view of the switch ,forming the presentinvention;

Fig. 2isa bottom vplan view of the switch operating mechanism; l y Y l f Fig. 3 isoan enlarged view showing the switch contact'and manner of securing it to insulators; e y

Fig`.4 is abottom plan view of Figp3;

v Fig; 5l `isa fragmentary section taken along the line 5f5 of Fig. 3.

The switch shown in Fig. 1 is of the under'slung type and comprises two' insulator stacks, 1 and 2, support from a base 3 which may be in the form of a channel as is the usual' construction. The insulator stacks I 2 are connected to the Vchannel base 3 through rotarybearings It and 5 which are interposed betweenthe channel 3 and the insulator caps -6 and 7.5; Y e

V The rotary-'bearings may befof the type disclosed'in my copending application, Serial No.y 137,926 filedy September 27, 1926. The insulator stackA 1 is fitted at `its lower end ywith an adapterl() suitably vsecured to the insulator pin 11 rby means of bolts, 12. A` contact 13 inthevform ofa substantially flat rectangular plate is bolted to the adapter 10 byv means offour 'bolts indicated at 14.

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The bolts 14 also serve to secure a T shape reenforcing member 15 to the blade 13. A bearing stud 18 having two forks at 19 is secured to the reenforcement member 15 by bolts 20 and acts as a bearing member for a lug support 22 having a projecting lug 23 to which a lead in line for the switch may be attached. The lug support Iis held in the bearing stud and is tree to rotate with respect to the lug support. As a result of this arrangement the lug support 22 is held stationary by the line that is connected to the arm 23 while the bearing stud rotates with the insulator stack 1. "A flexible conductor in the form of ,a copper braided wire 24 connects lthe lugV support 22 withr the contact 13 so that all of the current flowing through this switch is carried by the conductor 24 and does not have to pass through s the bearing member.

A bracket 28 is bolted to the contact 13 by means ottwo bolts 29 and supports a sleet shield 30 which is riveted or otherwise suitably secured to the bracket. The sleet shield 30 overlies the end of the contact 13 that is engaged by the switch bladein a manner `to bel vmore fully set forth presently and prevents the accumulation of ice or sleet upon the contact. j

A switch blade is secured to the bottom of the Iinsulator stack 2 in substantially the same manner as is the contact`13, an adapter 36 similar to they adapter 10 being j interposed between the switch `blade 35 and the insulator pin 11. The blade 35has a T shaped reenforcing member 38 secured to the bottomV thereof and this reenforcing member serves as a support for a bearing stud 40 of a. construction identical with the construction of the bearing stud 19. The bearing stud 40 supports the lug support 41 identical tothe lug support 22 upon the insulator 1. A flexible braided copper con- '1 ductor 42 connects the lug support with the switch blade 35. A pair'of contact jaws45 are mounted upon springs 46 at the end'of the switch blade 35, said contact jaws being adapted to receive the contact 13 between them.

An operating lever 5() is adapted to ro-A tate the ,insulator stack 1, said lever being secured to the bearing member 4 as shown in my above referred ,tofapplication The l rotary motion of the insulatorstack 1 is the switch to open due to the force between the contact 13 and the switch blade 35 by reason of current flowing through the' switch.

To open the switch the operating lever 50 is rotated in a counter clockwise direction as seen in Fig. 2, thereby rotating the switch blade in a clockwise direction as seen in Fig. 2. It is to be noted that at the commencement of the switch opening movement the switch contact 13 has a greater angular velocit than the switch blade 35. Due to the togg e action of the members shown a relatively great force may be exerted to break the switch blade 35 from the contact 13 through any ice or corrosion that may have formed. When the switch is closed the reverse operation occurs and the contact 13 is moved between the contact jaws on the switch blade 35 with a shearing action. This shearing action tends to clean the switch contacts as the switch is closed thereby maintaining good electrical contacts. It is to be noted that the edge of the switch contact 13 is beveled and that the contact jaws 45 flare outwardly. This facilitates the movement of the contact between the' jawsin that it serves as a guide for guiding the contacts into the jaws during the switch closing movement.

' There Ais a distinct advantage in arranging the "levers 51 and 52 so that they 'are in substantial Valignment when theA switch is closed and in providingan operating connection such as the lever for rotating the insulator. stack 1, and from this stack transmittingl the motion to the stack 2. In switches of this kind the operating lever is generally turned by means of a series of links which extend for an appreciable distance from the switch. The motion is transmitted through these links to the lever 50. Assume that the switch as initially installed is adjusted so that when the operating handle or the like at the end of the actuating link work is actuated to its extreme position the motion is transmitted to the crank 50 to rotate the insulator stacks 1 and 2 into the closed position as shown in the drawings; After a period of time it may happen that a certain-amount of free play is developed ice means that under such condition when the switch is actuated to its closed position. the contact 13 that is mounted upon the insulator stack 1 will be five degrees out of its true closed position. The same applies to the crank 51 that transmits the motion through the lever 52 to the insulator stack 27 and, when the operating mechanism has been moved to its full closed position the lever 51 will be approximately live degrees out of the position shown in Figure 2 in the example assumed. Under those conditions and 45 will vtherefore;engagey oneanotljler.y

with' theresult that the circuit throughy the switchis closed. n the 'other hand, as-

sume thatlthe driving lconnection 'of the lever were made to the insulator 2 instead of to the insulator 41.A f Under such condition if the same amount of free playshould'develop' in the link work that transmitsmotion tothe lever thenthe switch bladewould reach'its closed position' which would'be ve degrees out of its true position. Due tothe great length of the switch blade such ay Treat difference yin the, angular position `o? the switch blade mayy cause it to fall short of engaging the switch contact 13. The same result does not follow from a short angu lar displacement of the contact 13 due to the fact that this contact is vor' a much smaller length.

There is an additional advantage in locating the lever- 50 so that lthe' motion is irst transmitted to the contact supporting insulator and from it to the blade support ing insulator, This is due to the following condition: l Y,

Suppose that the switch has remained closed for a long period of time andthe cony tacts have become corroded together, rendering the opening operation difficult. A certain amount of freeveplay or looseness is inherently present in the connection between the insulators and upon the application'of a turning forceV to the crank 50 to open the switch the force is transmitted to the contact 13 which commences to turn to break the bind between it and the contactl 55. This turning commences very slightly in advance of the rotation of the switch bladev due to the inherent presence ofeven trifling amounts of free play. Thus the force vwhich tends to free the contacts from one another is transmitted at a relatively short radius whereby the stresses induced in theinsulators is small. Now, by reason of theffact that the crank 51 and the connecting rod 52 are Vin substantial alignment when the switch is closed a small-angular movement of the insulator 1 toward the open position produces substantially no movement of the `-insulator 2, hence all of the el'ort necessary to break the bind between the Contact plate 13 and the contact 35 may be transmitted through the insulator 1 at the relatively `short radius rather than through the insulator 2 and the relatively long blade. This would notbe true if the crankf 51 and the connecting rod 52 were not substantially in alignment when the switch is closed, evenif the actuating force were applied to the crank 50 connected tothe insulator 1' as, shown. Onthe vother hand if thev operating lever 50 wereE 'directly connected-*to the insulator' 2 and yfrom this insulator the connection: ex'V tended to the insulatorv 1 then theinitial turning movement would necessarily have lto Abe transmitted to the blade 3'51and,"sinc'e this blade' is relatively long,'there would be appreciable stresses induced in'theinsulator were in alignment when the switch is'closed.-

-` In compliance 4with. the vrequirements of the'patenty statutes I lhave herein shown and described a preferred embodiment of my in'- vention. It is however, to be understood that the'invention isnot limited to the precise construction shown, the Vsaine being' Vmerely illustrative.

W hat I considerrnew and desire to secure by Letters Patent is a lfAn'electric switch comprising a relatively short contact and a relatively Ylong switch blade both movable into and outffof engagementjwith one another, separate rotatable insulators for the `blade and the con-` tact, `means for rotating Y the contactv actuaing insulator to rotate the contact, 'and means comprising a .crank mechanism between the insulators yfor transmitting mo; tion to the blade actuating insulator, said crank mechanism being approximatelyA at its'dead center position wheny the switch is closed.il 2. Anf' electric switch including a pair of spaced. rotatable insulators, a relatively short contactrrotated by one 'of the insula-y tors, a relatively-longV switch blade rotated by therotherinsulator, said blade and con-k tact-being rotatedby` their respective insu-4 lators int'oand out of engagementwith one another, means for rotating the contact acI` tuating insulator, and means including a crank for rotating the blade actuating insulator, said crank being 'approximately `at its when the switch isV dead center position ClOSed; l. v 3'.' An electric switch including a pair of spaced rotatable insulators, a relatively short contact-rotated by one of the insulators, a `relatively'longswitch blade rotated by the other insulator, said blade and contact being rotated by their 'respective' insulators intol 4."An electric switch including a relatively short contact andV a'relatively long switch blade bothmovable into and out of engagement ywith lonev another, and means for Aimparting ak relatively great initial angular motion to the contact' and a negligible an-V fik its"- gular motion to the 'bladel `to initial-ly break the bind between ythe blade and the contact.

5. An electric switch including apair of rotatable v insulators, cooperating contact making members actuated by the insulators, means for lrotating one ot the insulators, and means including a crank. connectin the two insulators for transmitting motion rom said one insulator to the other insulator,said crank being approximately at its-deadcenter positionwhen the switch is closed. i

6. The method of separating a. switch blade from its contactwhich comprises, first retaining the bladey substantially stationary and turning the contact about a short radius to break the bind betweenA the contact and the blade,` and then actuating the blade away romthecontact to its "full open posi-V tion. i

7. A, switch comprising a` rotatably mounted switch blade, a. rotatable lcontact adapted to be engaged thereby, and means for forcing -the contact intoand out of engagement with said blade, said means vincluding meansv for simultaneously imparting a relatively great motion to the portion of the contact that engages the bladey and a negligible motion to the contacting portion of the blade upon the initial switch opening movement. C, j l; i

8. A switch including amovable switch blade, a contact at the end thereof, a second contact adapted to be engaged :by the first contact and forced into rm engagement therewith, means for actuating-,the second contact to loosen the engagement between the two while the switch blade is maintainedsubstantially stationary, and means for thereafter swinging said switch blade away from said second contact.V Y

v 9. An electric switch including ,a pair of crank arms, a connecting. rod connecting `the two, one of the cranks constituting the drivingk crank and the otherl constituting the driven crank, said driving crank having a normal switch open positionjand a normal switch closed position, said drivingccrank and connecting rod beingv in substantially their dead center position when `the driving crank is in its normal switch closed position, insulators connected to and actuated with the respectivercrank arms, and cooperating contact making members actuated by the respective insulators into and out of engagement with one another. .i

10. An electric switch including `a pair of crank arms, a connectingrod connecting .the two, one of the cranks constituting the o driving crank and the other constituting the drivenV crank, said driving crank having a normal switchopen position and a normal switch closedposition,v said driving crank and connecting rod being in substantially their dead center position whenthe driving crank is in its normal switch closed posi# tion, insulators connected tor and movablewith said crank arms, a relatively short contact mounted on the insulator connected with the `driving crank arm, and a cooperating relatively long switch blade actuated by the vother insulator, l 11. switch `ofthe type wherein a relatively short contact is engaged by a`relatively'longvblade and the switch is opened by rotating the contact about a comparatively short radius and the blade about a comparatively long radius, characterized by the; fact that the linear velocity of the end of contact is maintained appreciably above the linear velocity of the contacting end of thebladeduring the initial switch opening operation., o i

In witnessfwhereof, `I hereunto subscribe my namethis 23rd day ofApril 1929.

A o ALFRED ALSAKER.`

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