US1827430A

US1827430A - Electric switch and contact structure

Info

Publication number: US1827430A
Application number: US374837A
Authority: US
Inventors: Talma T Greenwood
Original assignee: Condit Electrical Manufacturing Corp
Current assignee: Condit Electrical Manufacturing Corp
Priority date: 1929-06-29
Filing date: 1929-06-29
Publication date: 1931-10-13
Anticipated expiration: 1948-10-13

Description

Oct. 13, 1931, T. T..GREENwooD A 1,827,430

ELECTRIC SWITCH VAND CONTACT STRUCTURE v Filed June'zg, 1929 Patented oa. 13.219'31 UNITED STATES PATENT oFFlcE 'rama r. GREENWOOD, or usr rmrm'ron,

MASSACHUSETTS, ASSIGNOB TO CONDIT ELECTRICAL IANUFAUIUBING CORPORATION, OF SOUTH BOSTON, MASSACHUSETTS,

-A CORPORATION lOAF IABSACKUBETTS ELECTRIC AND' CONTACT STRUCTURE application fuga nuera-192s. sei-iai No. 374,837.

v loto point contact is obtained. Consequently,

the use of contact members presenting spheroidally formed confronting contact faces is advantageous, since the heat is more readily absorbed and dissipated from the contact surfaces and vaporization of the metal thereof is diminished. Current flowing through the conducting paths of theswitch members is largely concentrated at the surfaces thereof, and consequently where the current is concentrated at the center or tips of the contact `members'the U-shaped 'current path thus present sets up a strong repulsiveforce which acts against the contact members in a direc- .tion to force therebetween.v

It is an object of this invention to provide means to overcome this repulsive force set up by the natural current path through the contacts' and further to enhance th'e contact presso sure therebetween.

Another object is the provision of a contactsupporting solenold having resilient convolutions which support one ofthe contact members, the convolutions being attracted ytoward each other when heavy current flows through them, whereby to press the contact member forcibly against the y cooperating contact member. A further object of the invention is the prothem apart and draw an arc 'rocable insulating switch rod 24 which is `the cooperating relatively fixed aroing con vision of means effective upon the tripping of p (ipe, o the relatively fixed contact members of 1*`ig.,3 is a detail view showing diagrammatically the current path through a pair of coo erating contact members, the repulsive a tenl ency of which is overcome by the present invention.

As herein shown, the invention isincororated in a down break electric switch havlng stationary switch members including the fixed conducting studs 10 which are enclosed vin insulating bushings 12 and stationary contact members 14 fixed to the lower ends of said'studs and provided with lower contact faces 16 which comprise the fixed main contact members of the switch. lSaid main contact members 14 are further provided with integral outstanding brackets 18 which are adapted to support the fixed auxiliary contact members hereinafter to be described.

The movable switch member includes a laminated, or brush, member 20 having upwardly directed toe-sections 22 which engage the contact faces 16 and a vertically recips, adapted to be connected with suitable operat- 7 'ing mechanism Spot-shown) for opening and closing the switc in the usual manner: Said movable switch member is further provided with a rigid horizontal bridging member 26 which is adapted to carry removably at its ends the upstanding auxiliary movable contact members 28. f

In accordance with the present invention,

tact members 30 are adapted to be supported yieldingly on said outstanding brackets 18. f

To this end, said contactmembers 30 as here Y shown are provlded with upwardly extended conducting shank portions 32 which are disposed alongside and in the same vertical planefwith the switch studs 10. Said shank portions 32 are screw threaded at their upper and lower ends whereby to carry the contact members 30 removably at the lower ends thereof. The upper screw threaded ends of said shank portions 32 are received in threaded apertures 36 at the upper ends of upstanding cylinders 38 which are carried removably by said outstanding brackets 18 and up- 100 said cy f substanti 'said contact members 30 as well as an electrically conducting solenoid series therewith. A sleeve 42 of insulatmg material is disposed about said conducting shank portions 32 in the vicinity of the brackets 1.8 whereby to prevent contact between said brackets 18 and said shank portions. A lock nut 43 is provided at the extreme upper threaded end of said shank portions whereby to secure them fixedly at their upper ends in cylinders 38.

The cooperating

arcm tips

28 and 30 are relatively massive where ylmore readily to absorb and dissipate the eat enerated at the contact-faces when an arc is rawn therebetween. It has been found that spherical contacts, or contacts havin spheroidallyformed confronting contact aces which present a single point contact, are articularly advantageous in this respect.- owever, the current path through a pair of such contacts, as indicated diagrammatically in Fig. 3, sets up a strong repulsive force due lto "the U- shaped current path in the vicini of the contact tips, as indicated at 44, which tends to force the contact members a art and cause a destructive arc to form there tween.

By the provision of the present invention, current passing throu h a switch stud 10' before passin through t e auxiliary contacts 30 is oblige lto traverse the helical turns of the cylinder 38 which is disposed about the shank portion 32 of the contact member and consequently sets up a magnetic reaction bev tween the convolutions thereof which tends to contract the convolutions of c linder v38 and consequently to urge the relatively fixed arcing member 30 downwardly into engagement with its cooperating contact member 28.

It will be evident that the more current assed through the switch, the greater wil be the force exerted against the contact member 28, which is held against downward movement by a latch or other suitable device associated with the switch operating mechanism, not shown. The shank portion 32 may be formed .of ma whereby to e ance the magnetic field and enhance the solenoid action of the convolutions of the cylinders 38.

A further advantage of this construction results, particularly when the switch is opened on heavy overload, in the initial acceleration imparted to the movable switch member by the solenoid action of the fixed arcing contact members. It will be obvious that this force operates to accelerate the movable switch member before the separation of the arcing contact members takes place so that a rapid movement of the switch member formed slot or kerf extending' netizable material if desired 1 is attained prior to drawing the arc between gaged contact members regardless of their configuration, so far as am now aware.

Itis old 'tovuse two mutually-attracted, unyielding contact supporting solenoids to hold the contacts engaged, but in such case one solenoid, alone, is without effect. Care must ,be taken in the design of such solenoids, otherwise the attractive effect-between them will hold the switch closed, regardless of efforts to open it. This cannot be the case with the present invention.

The magnetic field of the ent in the arc zone of the auxiliary contact members so that the arc is caused to vrotate about the contact membersand thus tol be the more rapidly extinguished.

The broad idea of utilizing a solenoid to rotate the circuit-interrupting arc is disclosed and claimed in my copending a plicatiin Serial No. 755,353, iiled Decem 1 24.

solenoid is pres- Various modifications may be made in the' t construction and arrangement of the parts vwithout departing from the scope of the invention.

I claim:

1. An electric switch including the combination of la fixed current conducting stud terminated in a maincontact block, a resilient solenoid having one end fixed to and electrically its other end free, an auxiliary contact member carried b the free end of said solenoid and vdisposed elow said main contact block, a

second and relatively unyieldindglyrsu portedauxiliary contact member a moved into enga ment with the contact member of said so enoid whereby to include said solenoid in the electric circuit including apte tobe said auxiliary contact members, said sole-` noid adapted when traversed by heavy currents to Hex in a direction toward said second auxiliary contact member and urge said auxiliary contact members into engagement by reason of the magnetic reactions the current traversing the turns thereof.

2. An electric switch including a relativey rigidly supported contact, a resilient solefree, and a second contact member carried by said free end, said solenoid arranged tol be included in the circuit through the switch' and, due to the current. traversing it, to move the contact member carried by the free end thereof toward said other contact member.

3. An electric switch including separable and exerts a force on one of said arcing memconnected with said block and set up by.

los

. noid having one end fixed and its other end "niv bers to .urge it in a direction toward and against the other when traversed by. the switch current.

4. An electric' switchincluding a contact, a resilient solenoid having one end fixed and its other end free, and a second contact member carried b said free and extended throu h said solenoi said solenoid arranged to .lie included in series with said contact member whereby to be influenced by the current traversing the circuit to ile'x axially and move its contact member into .pressure engagement with said other and cooperating contact member.

5. An electric switch including a contact, a resilient solenoid having one end fixed and itsfother end free and a second contact member carried'b)1 the free endof and extended through and insulated from the convolutions' of said solenoid, said solenoid arranged to be included in series with' the circuit through the switch whereby to be influenced by the current traversing the circuit to alter its effective length and move the contact member carried by its free end into engagement with said other and cooperating contact member.

6. An electric switch including the combination of a depending current conducting stud terminated inl a main contact` block, a resilient solenoid having one end fixed to and electrically connected with said block and 'tions of said soleno bracket, whereby to provide a current path havin its other end free for axial movement in a lrection parallel to the length of said stud, an auxiliary contact membercarried by the freeend of said solenoid, a lcooperating relatively rigidly supported contact member adapted to be moved upwardly into a definite circuit closing position in engagement with said first,contact member, the convolutions of said solenoid being included in series with said auxiliary contact members and adapted to be traversed by the current through the switch and to be influenced therebyy to effect an axial movement of its contact member into enga ement' with its cooperating contact mem r. I

7. electriclswitch including the combination of a fixed current conducting stud terminated in a main contact block having, an outstanding bracket, a resilient solenoid having one ende electrically connectedv with /said bracket and extended thereabove alongside said stud, a contact member electrically connected with the free end of said solenoid and extended downwardly through the convolutions and insulated from the convolu- 'd and also from said between said main contact block and said auxiliary contact member which includes the convolutions of said solenoid, a cooperating contact member movable upwardly into a deinite circuit closilg position wherein it is inl engagement with e contact member of said solenoid whereby to flex and lexpand said a support for the and adapted to solenoid axially, said solenoid arranged when traversed by an electric current to contract axially whereb to urge said contact meinbers in a direction to exert a pressure therebetween.v 7

8. An electric `switch including the combination of a fixed conducting stud terminated in a main contact block, a resilient solenoid having one end fixed to and electricall connected with said block and itsother en free; 55 a pair of relatively separable auxiliary contact members one of which isv rigidly supported and the other of which is carried by the free end of said solenoid, said auxiliary contact members havin confronting spheroi"- dally formed contact aces, means including the convolutions of said solenoid to overcome the repulsive force resulting from the normal current paththrough said contact members to exert an opposin force" on the contactrliv member carried there y to urge it against the other and rigidly supported contact member.

,9. An electric switch i'ncluding'thev combination of a pair of cooperating contact members having confronting spheroidallyo formed contact faces, one of which contact members is rigidly supported, and means including a resilient solenoid which constitutes other contact member in.- cludedin series with said contact members-.$5 and arranged to be deformed bythe magnetic reaction of the current passingtherevthrough toexert a force on the contact member carried thereby urging itinto engagement with said other and rigidly supportedoo contact member.

10. An electric switch including a. currentcontractible solenoid having a-ixed end and a movable end, a contact member carried by said movable end, and 'a second contact memselos ber cooperatingv therewith, said solenoid. being included in series with said contact member and arranged to contract by the current traversing it to urge its contact member against the other contact member. :511e

l1. An electric switch including a current- Icontractible solenoid havinglavixed end and a movable end, a contact member carried by said movable end, and a second contact member cooperating therewith, said solenoidvbell! ing included in series with said contact member and arranged to contract by the currentl traversing it to urge its contact member against the other contact member, said solenoid also constituting means to rotate thei. circuit-interruptin arc between said separated contact mem rs. 1

12. An electric switch having; separable contact members, and ,afsolenoid in series therewith providing ,a 'su port v:for one-0h12! them having s aced yiel ingv convolutions contracted axially to urge its contact member against the other contact f merpber when traversed by-the switchl curlen ,A .A I Y I' 13. An electric switch having separable contact members, and a solenoid in series therewith rovidinga su port for one of them, having s aced yiel mg Yconvolutions and adapted to contracted axially to urge its contact member against the other contact member when traversed by the switch current, said solenoid also constituting means t'o rotate the circuit-interruptin 'arc between said separated contact mem rs.

14. An electric switch having separable contact members, a solenoid havin yielding convolutions in series therewitg and a fixed end and a free end which is attracted toward said fixed end by the current traversing the convolutions, and means connect' one of saidl contact members with said free end so lthat said contact members will be urged-against each other by the contraction of the solenoid.

15. An electric switch having separable contact members, a solenoid having yielding 'convolutions in series therewith and a fixed end and a free end which is attracted toward said fixed end by the current traversing the convolutions, and means connecting one of said contact members with said free end so that said contact member will be urged" against each other by the contraction ofthe solenoid, said solenoid also constituting means to rotate the circuit-interrupting larc between the separated contact members.

16. An electric switch having separable contact members, a solenoid in series therewith h ving spaced convolutions which are free to attracted toward each other and to contract the solenoid by the current traversing them, supporting means, for one end of the solenoid, and means connecting a contact member with the other end of said solenoidv by which such contact lmember is urged against said other contact member by the contraction of said solenoid.

17. An electric switch having cooperating fixed and movable contact' members, a solenoid located thereabove having a fixed lower end and a movable upper end and connected in series with said contact members and having spaced convolutions which are attracted toward each other by the current traversing the solenoid, thereby to move the upper end thereof downwardly, and means lconnecting one of said contact members with said upper end .arranged to press said contact members together by the contraction of said solenoid.

18. An electric switch having cooperating fixed and movable contact members, a solenoid located thereabove having a fixed-lower end and a movable upper end and connected in series with said contact members and having spaced convolutions which are attracted toward each other by the current traversing the solenoid, thereby to move the upper end thereof downwardly, and means connecting -one of said contact members with said uprod which f noid,

` and having psr end arranged to press said contact memrs together y the contraction of said solenoid, said means including a rigid conductpasses .upwardly withinV said 19. An electric switch having cooperatin fixed and movable contact members, a solenoi located thereabove havin a fixed lower end and a movable upper end and connected in series with said contact members and hav' spaced convolutions which are attracted toward each other by the current traversin the solenoid, thereby to move the upper end thereof downwardly, and means connecting one of said contact members with said u per end, arranged to prem said contact memers together bythe contraction of said solenoid said means includin a rigid conducting rod which passes upwa ly wlthin said solenoid, and is composed of ma etizable material.

20. An electric switc having cooperating fixed and movable contact members, a solenoid located thereabove having a fixed lower end and a movable upper end and connected in series with said contact members and having spaced convolutions which are attracted toward each other by the current traversin the solenoid, thereby to move the upper end thereof downwardl and means connecting one of said contact members .with said upper end arranged to press said contact members together by the contraction of said solenoid, sald solenoid also constituting a resilient support for its contact member.

21. An electric switch having cooperating fixed and movable contact members, a solenoid located thereabove having a fixed lower end and a movable upper end and connected in series with said contact members and having spaced convolutions which are attracted toward each other by the current traversin the solenoid, thereby to move the upper en thereof-downwardl and means connecting one of said contact members with said u per end arranged to press said contact mem ers together by the contraction of said solenoid, said solenoid also constituting a resilient support for its contact member and also means to rotate the circuit-interrupting arc between said contact members.

22. An electric switch having a support, a resilient solenoid having axially-spaced convolutions fixed at its lower end to said support an upper end which is free to move toward said fixed end by the attractive effect of the current traversing theconvolutions, a stud connected mechanically and also electricall with said free end and extended downwar ly therein, a contact member carried by the lower end of said stud, and a movable contact member dis osed below and cooperating with said fixed) contact member.

Y 23. An electric switch havin a fixed contact member, a relatively rigi ly supported movable contact member cooperating therellO with and movable into a definite switch closed position, and a spiral compression spring yieldably supporting said fixed contact member, whereby it can move while engaged by said movable contact member, said spring being electrically in series with said contact members and including means to urgeits contact member into engagement with said cooperating contact member when traversed by the switch current.

24. An electric switch having separable contact members, a support of magnetizable material for one of said contact members, and means to magnetize said support including a solenoid which also providesl a yielding support for said contactsupport.

25. An electric switch khaving separable contact members, a support of magnetizable material for one of said contact members, and means to magnetize said support by the current traversing said contact members. including a solenoid which also provides a yielding support for said contact support.

26. An electric switch including separable contact members having engageable contact faces, a magnetizable support for one of said contact members extended thereintoand terminated adjacent the contact face thereof, and means to magnetize said support including a resilient solenoid which is fixed at one end and carries said magnetizable support at its free end.

27. An electric switch including separable I contact members having engageable contact faces, a magnetizable support for one lof said contact members extended thereinto and terminated adjacent the' contact face thereof, and means to magnetize said support including a winding which surrounds said support andhis `connected electrically in series therewit 28. lAn electric switch including the combination of a pair of cooperating contact members, and means included electrically in series with said contact members and constituting a support for one of them which actsv to urgeits contact member by electromagnetic forces due to current traversing the yswitch into engagementwith its cooperating f contact member and which also acts to set up a'magnetic field which acts radially of the line of separation of said contact members whereby to rotate'the circuit` interrupting arc drawn therebetween.

VIn testimony whereof, I have signed my name to this s ecification.

TLMA. T. GREENWOOD.