US1412002A - Switch mechanism - Google Patents

Description

A. B. HENomcKsjlR. SWITCH MECHANISM.

APPLICATION FILED FE8.14, 192i.

1,412,002. Patented Apr. 4, 1922.

2 SHEETS-SHEET l.

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H i s Attorney. Y

A. B. HENDRICKS, Ja.

SWITCH MECHANISNI.

APPLICATION FILED FEB. 14. 1921.

1,412,002'. Patented Apr. 4, 1922.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

ALLAN B. HENDRICKS, JR., OF PITTSFIELD, MASSACHUSETTS, .ASSIGNOR T0 GENERAL ELECTRIC COMPANY, A CGRPORATION 0F rNEM? YORK.

SWITCH MECHAN'ISM.

Specification of Letters Patent.

Patented Apr. 4, 1922.

Application filed February 14, v1921. Serial No. 444,777.

T 0 all 'whom t may concern:

Be it known that l. ALLAN: B. unions, Jr., a citizen of the United States, residing at Pittsfield, county of Berkshire, State ofMassachusetts',A have inventedv cer tain new and useful Improvementsin Switch Mechanism, 'otwhich the following is a specification. j i 7 My invention relates to switch mechanisms for electricalv apparatus.` More particularly my invention relates to sw'itch mechanisms which are'l adapted to adjust voltage ratios in stationary induction electrical `apparatus having windings provided with taps for that purpose. 1

`The service required of tap changing or switching mechanisms adapted to adjust voltage ratiosis very diilerent from' that required of ordinary switch mechanisms.l In `ordinary cases'the Eswitch*mechanism must be arranged to rupture safely the maximum current which it is designed to carry.

In ratio adjusting evices, however, the problem is reversed. YThe mechanism is only required to rupture a relatively small current (the magnetizing current in transformers or auto-transformers) in comparison with that carried during normal operation since it is generally not permissible to adjust voltage ratios under load. The problems of quick makes and breaks and of quenching arcs arc accordingly relatively unimportant. On the other hand` the mechanism is'required to carry the full load `current under operating: conditions. The problem of securing adequate contact between the current carrying parts and providing adequate ventilation accordingly becomes signally important in this type of service since it is imperative to provide such mechanism without undue weight or bulk.

In accomplishing my invention I provide an improvedarrangement of 'parts which is simple and-rugged with all current carrying parts exposed and accessible to ventilation. The contact-making parts are designed always to make line contact so as to have maxi mum current carrying capacity. To this end l employ a spherical bridging member in preference to any other form and arrange it to engage correspondingly grooved Contact posts; the bridging member in this form being capable of considerable seltadjust` ment so as to make a line in spite of slight variations in the alignment of the Contact posts. y y

For a more complete understanding of the nature 'and objects of my invention. refer` ratios which is constructed in accordance With my invention; Fig. 2 is a vertical'sectiorrof the mechanism shown in Fig. 1, while Fig. 3 is a horizontal section of the same mechanism; Fig. f1 is a View similar to Fig. 2, but of a modified form of mechanism which is adapted to carry larger currents than theiirst form shown; Figs. 5, 6, 7 and 8 are sectional, plan and detail views of another modification of my switch mechanism which is part'iciilarlyy adapted for use on the exterior of casings for electrical apparatus. while Fig. 9 shows a further modification ot the form of switch mechanism shown in Fi .5.

eferring now to the drawings. and to Fig'. 1 in particular, 10 and 11 denote respectively upper and lower discs of insulating material which are provided with contact posts 12 evenly spaced about their circiuntercnces. These contact posts preferably have reduced portions 13 extendingr through the discs l() and 11, thelower portions being provided with connecting members 14- to which lead the taps from the electrical winding whose voltage ratios are to be changed. Each contact post 12 is also grooved circumferentially with a groove whose radius of curvature is the same as the radius of the spherical bridging member 15 which is mounted in and is moved by the rotatable member 16.

The bridging member 15 is a ball of good conductingr material and reciprocates in the cylindrical recess 20 which is formed transverse to the axis of rotation of the rotatable member 16. Back of the ball 15 and reacting against the bottom of the recess 2() is the springr 21 which presses the ball out of the recess so that it. protrudes slightly between a pair of contact posts 12 as shown in Fi 3. at the same time forcing the ball into intimate engagement with each of the circumfercutial grooves on the Contact posts 12, thereby making complete contact throughout the arc of thergrooves.` The bottom of the recess 20 is preferably provided with a vent openingr 22% as shown. y

The rotatable member l |s provided with shanlrs 24 and 25 journaled in the discs 10 and ll centrally of the Contact posts l2. one such shank 25 being extended to serre as an operating shaft. a pin 26 being preferably provided for securing an operating handle to the shaft.

The construction just described is compact and light and lends itseltl rendi!) to the production of a verdv rigid structure. the disc being prevented from displarrnient by the screws and washers at 2S `which cu- 5 gage with the upper reduced portions of each of the Contact posts. The disc 11, however` is Shown as secured by means of pinsi 29 which enter the disc radially and engage with openings in the lower reduced portions of posts l2.

All current carrying parts are thusv located about the exterior of the device and accordingly are well ventilated, the strurture being?r adapted to be fitted down beside the Winding from which the voltage ratio ad'usting taps lead.

he advantage of the curvilinear engagement of the current cariving members (the ball and contact posts) in this construction is obvious when 1t is considered that if we had cylindrical contact posts to be engaged by a bridging member with a cylindrical surface, then an)y slight disalignment of the members at once prevents line contacts from being made. Point contacts result with consequent overheating of the parts when carrying full load current. In my construction, however, the arcs of the circumferential grooves on the contact posts l2 are segments of great circles of the spherical member 15. Hence Whatever the alignment of posts 12 they will engage throughout the length of their arcuate grooves with the surface of member l5; a. line cont-art thus always resulting.

In Fig. 4 I have shown au arrangement adapted for higher current carrying capacity than the form first described. Here the rotatable member 3G carries a pluralit)V of spherical bridging members 35. three heing shown; which members reciprocate in individual recesses 40, similar to those at 20, formed in member 3G.

In this form the Contact posts 3Q carried by the insulating discs hare ,'ii-cuinleren tially formed grooves which have radii of curvature corresponding respectively with those for each of the balls or spherical mein` bers 35. The posts 32 are thus shown each with three grooves. the crosssectional area of the posts being niade snllieicnt to impart the desired. mechanical stillness to the con struction.

lu Fig. 5 a, construction is illustrated partlcularly adapted for mounting on the cx terior of the casing containing the winding having the voltage changing taps.

Insulating discs 5t) and 5i are here again used to support the contact posts 5:2 which are evenly spaced about their circumferences. The up )er insulating disc 5f) here, however, is ma( e larger than the lower one since it is desired to provide it with a margin adapted to support the devire. Ac cordingly, this margin has openings at which are adapted to receive bolts or other suitable means for securing the device to the casingr wall.

The contact posts 52 are circumferentialhv grooved as before, but are hollow and are slipped ovei` and adapted to revolve about the stationary cylindrical cores 53 which have their reduced ends- 5l secured in the discs 50 and 51.

A spherical bridging member or ball 55 is carried b the rotatable member 56 which is journals( centrally of the contact posts 52. The lower journal of the rota table member is shown at 5T turning in a-bushing 58 secured in the disc 5].. The upper journal :39 is likewise hushed and extends suflicieutlv to have a. manipulati-ngr hand-le G0 secured thereto by means of pin 6L In the construction illustrated it is desirable to have the ball 55 carried not di rertly by thexottable mem-ber but by a plunger 65.mountcd and reciprocating in the recess 66. in the rotatable member. which plunger is pressed outwardly by the spring 67 in the recess.

In order that the ball 55 may turn with as little frieti as possible I mount it on the axial pin Illiwhich traverses an axial bore in the ball 55 and has its ends engaged with upper and lower slots T1 cut infthe-plunger 6:5. The pin 70 is somewhat extended at. both ends to project' beyond the slots T1 and upper and lower annular grooves T2 arf` formed in-tlw inner 'laces of discs 50 and 5l in which the endsof the in track. These grooves need not be complte annnli where it is desired to have them discharge a stop function.

For a. similar resonit is desired that the contact posts 52 shall be rotatably mounted on their stationaryA cores 53, i. e. in order to reduce friction in the moving parts when tht` ball 55 i's moved to change tap coi-mec tions. By this arrangement sliding friction in the structure is reduced to a minimum and rolling friction is substituted.

The construction shown in Fig. 5 is adapted to have the taps from the windings secured to the contact posts 52 in a very advantageous manner. To this end thc cores 53 are made tubular. their upper Vends boing disposed in countersunk recesses formed in the upper face of the` list` :3U These ends have threaded lcerfed washers it), which may be screwed down by a suitable tool, when enga 'ng the lrerf, so as to engage with and hol securely the tip end of the tap lead; the latter as shown at 77 has its terminal portion stripped and inserted up through thebore of the core 53, its ti n nall)y being bent over and brought out though the slot T8 formed in the side of the upper end of core 53, which is clearly shown in Fig. 7.

This construction permits the switch mechanism to be secured in place on the vwall of theapparatus casing and the tap connections made afterwards. When this procedure is followed the handle 60 is removed,

the pin 61 having first been displaced. `The stripped ends of the tap leads, which preferably were partially inserted before the switch mechanism 'was finally secured, are then drawn up into place,V the tips bent out through .the slots 78. andthe washers 76 screwed into placed. The handle 60',m`ay now be replaced and the switchxnechanism placed in operation.

The modification shown in Fig. 9is simivlar to that shown in Fig. 5 butthe cores 53 on which the cylindrical contact posts 52.

turn, are not hollow..l Instead they are solid 'and have an ordinaryI screw andl nut a'rrangement 4for holding them inthe countersunk openings S5 in the topy face-of thez disc 50,l a similar construction 'obtaining at the lower end: at this latter end, howevena countersnnk washer 88 is used in additionto the ordinary washer 89 between which the tips of the tap leads are secured.

Having now describedA several embodiments of my invention which are at present the best means, known to me for carryingr the same into effect, I would have it understood that these are merely illustrative and that I do not mean to be limited thereby to the precise details shown nor restricted in the choice of recognized equivalents except as defined in my claims hereunto annexed.

That l claim as new and desire to secure by Letters Patent of the United States, is

l. A switch mechanism adaptedor tap changing comprising in combination a pair of insulating discs. contact posts having circumferential grooves disposed about the peripheries of said discs. a rotatable member disposed between said discs centrally of said Contact posts. and a spherical bridging mcmher in said rotatable member and arranged lo engage with said grooves.

2. .l switch mechanism adapted for tap changingr comprising in combination a pair of insulatinpr discs. contact posts having circumferential grooves disposed about the peripheries of said discs. a rotatable member disposed between said dises centrally of said contact posts. said rotatable member having a recess. and a spherical bridginpr member mounted in said recess and arranged to engage with said grooves.

3. A switch mechanism adapted for tap changing comprising in combination 'a pair of insulating discs. Contact posts having cir cumferential grooves disposed about the peripheries of-said discs, a rotatable member disposed between said discs centrally of said Contact posts. said rotatable memberhaving a recess. and a spherical bridging member resiliently mounted in'said recess having the same radius of Curvaturelas said grooves and arranged to engage successively 'eaclifpair of rzrooves as the rotatable member'is'turned.

4. A switch mechanismI adapted for tap changing comprisingin combinationa pair of insulating discs,'cont`act'posts having circumferential groovesdisposedjahout the peripheries of said discs', 'a rotatable'member disposed between said dis'cs'cnt'raliy'o'f' said contact posts and havi'ligfia reeess, a spring in the recess, ad'a sphericalb'ridgingimem ber mounted 1n sald recess reacting'against said 'spring andadaptedto `protrudei partially between a-'pa'ir ofrcontact posts and engage with their-circumferential ygrooves.

5. A switch V mechanism adapted for tap changing comprising-lin cor'nbin'ation'a pair of insulating discs,'contact posts'havin'gcircumferential grooves disposed 'abo'utithe'peripheries of said discs, afro'tatablmember disposed between said discscentrallyof said contact posts and havinga recessaspiringin the recess, a conducting l'ball in 'said lrecess'having the same radius' of curvature as said groovesreacting aga'instjsaidV spring and adapted to protrude between and bridge a pairof Contact posts in the region of their circumferential grooves.

6. A switch mechanism adaptedaeorA tap "changing1r comprising'in combination apair of insulatingdiscs, contact p osts having cir- 'cumfere'ntial grooves disposed ah'utfthe peripheries of said discs, a rotatable member disposed between said discs centrally of said contact posts and having a recess, a. spring in the recess. a plunger in the recess pressed outwardly by said spring. and a spherical bridgingT member mounted in said plunger and adapted to engage with the circumferential grooves of a pair of contact posts.

7. A. switch mechanism adapted for tap changing comprising in combination a pair of insulating discs, contact posts having circumferential grooves disposed about the peripheries of said discs, a rotatable member disposed between said dises centrally ot' said contact posts and having a recess, and a spherical bridging member axially supported in said recess and arranged to engage with the grooves in said posts, said posts arranged only for rolling;r rictional engage ment by said bridging member.

Fi. A switch mechanism adapted fdr tap changing comprising in combination a pair of insulating discs` contact posts having cir rumfcrcntial grooves disposed about the peripheries of said discs, a rotatable member disposed between said discs centrally of said Contact posts and having a recess, a plun er resiliently supported in said recess, an :i spherical bridging member having the same radius of curvature as said grooves axially supported by said plunger, said posts being adapted to rotate and to have their grooves engaged by said bridging member.

9. A switch mechanism adapted for tap changing, comprising in combination a pair of insulating discs, Contact posts having circumferential grooves disposed about the .peripheries. of said discs, a rotatable member disposed between said dis centrally of said contact posts and ha\'i a recess, a plunger .resiliently supportiI in saidv recess, a spherical bridging member having the same radius of curvature as said grooves, and meansifn said' plunger axially supporting saidbridging member, said contactposts liaving-'intorior cores. mounted stationary between said-dis and exterior cylindrical portions turning-on saidv cores and. adapted for rolling frictionalfengagement by said bridging member-in the region of their grooves.

l0..-A switch mechanism adapted' for tap' changing comprising in combination a pair o-f insulat' A discs, contact posts having circumferentlil grooves disposed about the peripheries of saiddiscs, said posts having axial hollowportions each adapted to ieeeive the endof a tap lead, a rotatable mem- -bcr disposedroentrally of said contact posts,

and a spherical bridging member carried by said rotatable member and arranged to engage with Said conta/ct posts-inthe region of their grooves.

11. A switch mechanism adapted for tap changing comprising in combination a pair of insulating discs, contact posts having eircmnfercntial grooves disposed about the IQ- ripheries of said discs, cach o( said posts vharing an axial bolloY portion adapted lo p ostst and a spherical bridging member carf ned by said rotatable member and arranged to engage with said posts in the region of their grooves 12. A switch mechanism adapted for lap changing comprising incoinbination-a pair ot insulating discs, contact posts havin,"r cirA cumfcrential grooves disposed about the peripheries of saiddiscs, said posts having hollow core portions mounted stationar)Vr between said dises, each post being adapted to receive the stripped end of u tap lead and havingouter-cylindrical portions turning freely on said core portions, a rotatable member disposed centrally of said cont-uct postsranda spherical bridging member llav- 'ing the same radins ofcurvature :is said grooves and suspended :Ixo-illy in sani :ni-

tatable member, Asaid bridging member bein;r adapted to turn freely about such axis of suspension and engage with said contact posts in the region of their circumferential grooves, whereby there is a line contact in all operative positions between said bridging member and a pair of contact posts. there being only mllin; r friction between the parts when said bridging member is moved from one operative position to another. y

In witness whereof, I have hereunto set my hand this 9th day of Feb.1 1921.

ALLAN B. HnNDRIcKs, JH.

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