US1018196A - Automatic switch. - Google Patents

Description

C. L` KENDUEIDYIV AUTOMATIC SWITCH; APPLIGATION FILED 1120.13, 1909.

ITD@ en E {Dr-#Q Patented Feb. 20, 1912.

disclosed vin the patent to Donald M. Bliss, No. 860,124, granted July 16, 1907, and the' UNITED sTATEs PATENT our 11er.

'CARLTON L'. KENNEDY, or SOUTH ERAINTREE. nnsscnusn'r'rs, as sIGNoR To THE ynorxrzmt-cABo'ri- ELECTRIC COMPANY, oE BROOKLLNE, MAssAci-Iusnirrs, .a` ConroyRATION OF MASSAQHUSETTS.

AUTOMATIC SWITCH.

Vfo all whom' 'it may concern."

"mentsl in Automatic Switches; and Il do 4h'erebydeclare the following to be a full,

clear, and exact description of the invention,l such as will enable others skilled in the altto which-it appertains to make and use the same.

The present invention relates to automatic switches for /use in 'connection with indue tion motors of the split-phase type.

rent in'which the phase is displaced relatively to the phase ofthe current in the nor- Imilly-operative or working winding if the stator in lorder 'to produce, in'coperation with the working winding. a rotary field. '.hen thc motor has attained a predetermined 'speed the starting winding is cut out by 'the operation ofthe automatic switch. n switchA of the type above referred'to is l'nesent invention is an improvement upon the switch disclosed in said patent.

In the patent above referred to the switch comprises a base member adapted to be mounted upon-the shaft of the motor so as to be rotated thereby. This base member carries agfixed contact member and a movable contact member. The movable contact member fcomprises an ai'mpivoted at one end to the base member and carrying it at its free end, and a pivoted contact piece adapted to engage the-fixed contact member. A spring connected with the pivoted armv holds the y.Contact.`members normally in engagement',

ybut upon the attainment of a predeterminedv speed of rotation,-the centrifugal force acting upon the arm causes lit to swing outwardly s as to disengage the fixed contact member` -and thereby break the circuit through the starting winding. l

The function of the pivo'ted contact piece mountedupon the arm is ,to secure a sliding engagementwith tbe fixed contact member In a motor ot this'type an auxiliary stator wind-` ing is employed in 'starting the motor, this Vstator winding being energizedby a curprevious to their complete'disengagement in order thatv the breaking of the'circuit may occur at a diierent point on the lixed contact member from that normally engaged by Speeicaton of Letters Patent. Patented Fel). 20, 1912. Application filed December 13, 1909. Serial No. 53.21.803. I

the movable contact member, and in this way injury to the surface of the fixed contact member dueto lthe arcing which 'occurs at the breaking of the contact isvprevented from affecting the Contact surface normally engaged by the movable Contact member.

The object of lthe present invention is to secure the advantages of t-heconstruction above described in a simple manner ,and by the use of only a single moving part con-v time moving in the general direction to.

cause disengagement, so as to have a sliding contact with the fixedcontact member unt-il disengagement occurs.

Other features of the invention will be setforth in connection with the description of-the illustra-ted embodiment thereof.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which- Figure l is a vertical 'section of an autothe section being'taken on the linel-l, in

Fig. 2. Fig. 2 is an elevation of the switcln' partly in section on line 2-2; in Fig. l.

Fig. 3 is a section ofthe switch ony line 3 3, in Fig. 2. Fig. 4 is a. diagram illus. trating the electrical connections between the switch and the motor.

The switch illustrated in the drawingsis provided with a fixed contact member 4 in the form lot' a metal pin projecting inwardly from a flat ring 5. `The' ring 5 kis secured vmatic switch mounted-upon a motor shaft,

byA screws 6 to a fiat ring 7 of conducting i material, but is insulated therefrom by' insulating' material S. The ring 7, Whichconstitutes the base or mainsupportingfmember ot the switch, is' integral with armsproject ing from a. central hnb` 9, and this hub provided at its free extremity with a recess I4. which conforms to .the surface of lthe fixed contact-member 4 and constitutes a Ybutt-ing-contact surface through which elec.

contact members. l

mounted `upon the shaft 1 0 of the motor, being insulated therefrom bv'means of a bushing 11 of insulating material. 'The shaft 10 carries the rotor 12 of the motor so that the switch rotates as a wholeV at the 'same speed as the rotor.

The movable contact member is the form of a curved arm 13, This arm is trical Acontact is normally made between the Extending from the con. tact surface 14 to theextremity of the arm 13 is a"'sliding#contact surface 15 which is adapted to engage-'the fixed contact member fslidingly as the arm moves .itselffrom the fixed contact 320 7 in' such a manner as to' cause it to be acermit it to' -a pivot to disengage memberl The arm 13 is connected with'the base or ring tuated by the latter but tohave movements in two directlons thereon. -To this lend vthe arm is provided with an opening or recess 16 which is engaged by pin or abutment 1744 projecting from the base ring 7. The pivot pin is. substan- `tially smaller than the opening 16, so that "gal force acting upon `.movement of translation securin the 4arm may have not only a Vpivotal or angular-movement about this connection, but may also have' a lateral movement or for the purpose of the slidingV engagement hereinbefore re erred to.

by means of a spring 18 connected at one end tothe base member and at the other end i to the arm.13 near its pivotal-support.

Whenthe switchis in rotation the centrifuthe movable contact member tends to swing it outwardly'abou pivotal support so as tti disengage from the fixed contact member.' The position of the sliding-contact surface 15 with relation to the position of the opening 16, and the shape of the latter opening, and the relation of these to the positions of the fixed-contact a member 4 and the pivot pin 17, the point of application of the spring y18 and its direction of pull on the curved arm 13, together With the position of the center of gravity of the arm 13, are such that when the arm 13 is movedin an outward direction the tendency is to hold the sliding-contact surface `15 in engagement with the fixed-contact member 4 until the swinging movement of the arm separates the contact members entirely. The result of the centrifugal action is, therefore, to cause the movable contact member first to swing outwardly so that the butting-contact surface lltis `disengaged fromthe fixed contact member but to con# tinue in` engagement with the contact inem-V ber, through the sliding-contactsurface 15,

`of breaking will -tact surface 14;,

'to the arc of'movement of The contact members are normally heldy 1n engagement, when the motor is at rest.-

until the extremity' of this surface is sepa- 'l rated from the fixed contact member by the continued outward swinging movement of the arm.` The circuit is then broken-at the extremity of the moving contact member, so that any arcing which occursat the instant not affect the butting con? andthe normal electrical' contact between the -contact members will not, therefore,`-beimpaired -by the burning of 'the movable contact memberdue to the The arm 13 has its slidingfcontact surface 15 inclinedl at a comparatively small angle the free end of pivotal connection sald arm about the arm 13 is moved to 16-17so that when the vclose 4the circuit the surface 15' will rideover the'y opposing parallel sliding-contact surface of the round fixed contact member 4 until the butting-contach surface 111: is

brought into engagement with the fixed .co ntact'member 4. The recess 16 is larger than Vthe pin 17 in a direction substantially normal-to the arc of contacting movement o fl the free end of the arm 1,3 so that a sufficient outward radial movement is permitted the arm 13to allowthe inclined sliding-contactl surfaces of the movable and xed contactv It is to members members to ride over each other. be observed that the two contact are relatively movably mounted upon the base, that one of them 1s an integral arm pivoted on the'base and adapted to be actuated by the rotation thereof, and that said contact members have sliding-contact surfaces somewhat inclined to the direction of the arc of the movement of the pivoted arm, and also that one of the contact members is provided with a mounting comprising a re`4 cess and a pm engaglng the' recess which recess is larger than the pin in adirection which issubstantially normal to the arc of contacting movement of the arm so as to allow the two cooperating sliding-contact sur? faces to ride over each other, and that the sliding-contact surfaces are yieldably held in engagement during their riding or wiping engagement. Since the sliding-contact sur-1 facesare inclined at a comparatively small angle to the arc of swing of the arm, the movement of the sliding-contact surfaces, which is due to the transverse movement of the pin in the recess, is in a direction which is substantially'finclined to said' sliding-com tact surfaces.

The outward movement of the movable contact member is limited by a stop 19 projecting fromthe base ring 7.v The .base ring is counter-balanced by means of a weight 20 integral therewith to compensate for the centrifugal action of the movable contact member. A vane 21 is lfixed to y to `promote the circulation of air between the switch and the rotor, anda vane 22`is the base ring liked to the movable contact member for a similar purpose.

. The mannein which the switch is used is illustrated diagramm-atically in Figa. Two brushes 23 and 24. are arranged to en gage the outer surfaces of the rings 5 and 7 to make electrical, contact therewith, and these' brushes are connected, through Wires 29, respectivelymith one of the feed termi nals 26 through which the motor is supplied with current, and with one terminal of the star-ting Winding 27 of the motor. The Working Winding of the stator is permanently connected with the feed terminals 26,

15 and one terminal of the starting Winding 2 y Vis also connected, by a wire 28, with one feed terminal.

The above-described connections are such that. .when the switch 'is in the closed-circuit 2|) position illustrated in the drawings, the starting Winding 27 is energized from the feed terminals; but as soon as the switch 'operaltes through centrifugal force, as above described, thec'ircuit is broken through the starting winding and the motor operates under the intiuence of the Working windin'g alone. VAAn electrical connection is formed' through thejoint 17 from the ring 7 to t-he arm'lBwhich consists of an integral piece 'of metal, and has a contacting surface 14f-15-formed' directly thereon.v

By my improved construction above described .dispense 'With the use of the jointed arrangement' of the two-part movable con tactmember employed in the construction disclosed inthe Bliss patentbefore referred to, thereby'v rendering the device more simple in' construction and also avoiding the necessity of conducting :electricity through a mechanical joint inthe. movable contact member. Owing to the 'same simplification in construction, the operation of the device is rendered more reliable, since the entire Weight. of the movable contact member is utilized to maintain the sliding engagement with' the xed contact member, and since this. action does not depend upon an additional joint which is .liable to stick, due to the presence of lubricating oil or dirt. '50

bodiment hereinbefore described and illustrated in the accompanying' drawings, but itmay be embodied in other forms within the nature of the inventionand the scope of the followingclaims. I claim 1., An automatic switch, having, in combination, a base, a fixed contact memb'er and a movable rigid' contact member mounted thereon, one of the contact members being provided With a sliding-contact surface adapted lto engage the other contact member, the moving contact member' having direct mechanical connection with the' base so as to be actuated by the rotation" thereof, and such My invention is not limited to the em! connection having provision for movement of the movable contact member, by centrifugal action, both in a direction to secure slide ing engagement. between the sliding-contact surface and the cooperating contact member and in a. direction to cause the movable contact member to slide beyond and disengage the fixed contact member.

2. An automatic switch, having, in combi"- nation, a base, a fixed contact member and a movable integraLcontact member, one ofthe Contact members having a butting-contact surface and a sliding-contact surface arranged at an angle .with each other,themovable contact member having direct mechanica-l connection with the base so as-to be actuated by the rotation thereof, and such connection having provision for movement of the mov able contact member under centrifugal action both in a direction to secure sliding engagement betweenv the sliding-contact surface and the coperating member, and in a direct-ion to dslide out of lengagement With the fixed contact member.

3.An automatic switch having, in comb nation, a base, twoV relatively movable contact members mounted thereon, one of which comprises an arm pivoted on t-he base and adapted to beactuated bythe rotation ther`eof, one of said contactmembers having a pin and recess connection with the base, the re- Cess being .larger than the pin in a direction substantially inclined to the surfaces of the contact' members lwhich first engage each other, 'to allow the contact members to have a wiping engagement Whenthey make and break contact, and means to yieldinglyhold- -said surfaces in contact during their Wlping engagement. A 4. An automatic switch, having, in combination, a base, a fixed contact member, a movable contact member and `a'sp'ring connected with the movable contact member and tending normally to maintain it in engage? ment with the fixed contact member, the movable contact member 'being in the form of an arm pivotally connected at one end With the base, the pivotal connection having provision both for angular movement of the arm to permit it to be disengaged from the fixed contactmiember by centrifuga-l action, and for transverse movement *of the arm to permit a sliding engagement between the arm and the fixed contact member.

5. An automatic switch, having, in combination, a base, a fixed contact member,a

movable contact member, the movable contact member being-in the form of an arm adapted to engage the fixed contact member at one end and connected at the other end With the base by a connection comprlsmg a4 recess and a pinengaging the recess, the r ecess being substantially larger than the pln to allowl the movable contact member to have a wiping engagement with the fixed contact member when the two members make or break contact, and a spring connected Vto the movable contact member and having a component of its -force in a direction normal to that part of the suriace of the fixed contact member which is first engaged by the mov able contact member to insure the wiping engagement of these two members,

6. An automatic switch having, in combination, a' base, a fixed contact member, and a mov able contact member pivotally mounted on the base, said contact members having opposing slidingcontact surfaces inclined at a comparatively small angle to the arc of contacting movement of the piyoted member, and said movable member having ineluded in its connection with the base a pin and recess, tbe recess being larger than the pin in a direction substantially normal to tact members, y mounted on the base,

said are of movement, to permit said inclined slidingcontact surfaces to' rideI over each other.

7. An automatic switch having, in combination,V a base, two relatively movable 'conone of which is pivotally said members having opposing sliding-contact surfaces incline to the are of contactingmovement of thev pivoted member, and one of said members having 'a pin and recess connection with the base, the recess being larger than the Ypin in a direction substantially normal to said arc of movement, to permit said inclined slidingcontact surfaces'to ride over each other.

CARLTON L. KENNEDY. Witnesses:

RoiY T. VVELLs, MATTHEW PoRosKr.

'Correction in Letters Patent No. l-,018,196.

It is hereby certified that in Letters Patent No. 1,018,196, granted February 20,

1912-, upon the application of Carlton Ibflennedy, of South Braintree, Massachusette, for an improvement in Automatic Switches, an eri'or-a'ppeai'sin the printed specification requiring correction as follows: Page 1, lino 21', .for the word if read of; and that the said Letters Patent should be read with this Correction therein that the same may conform to the record of the oase in the Patent VO-iee.

Signed and sealed this 26th clay of March, A. D., 1912.

C. C. BILLINGS,

Acting Oommz'ss/oner of Paiens.

[SEAL]

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