US2673264A - Circuit breaker with adjustable thermal and magnetic controls - Google Patents

Description

T. M. COLE CIRCUIT BREAKER WITH ADJUSTABLE March 23, 1954 THERMAL AND MAGNETIC CONTROLS 2 Shegts-Sheet 1 Filed April 17, 1952 F/Lii.

} INVENTOR. 77/0444; M. (01.5 66 BY WM JrfaK E/J March 23, 1954 E 2,673,264

' CIRCUIT BREAKER WITH ADJUSTABLE THERMAL AND MAGNETIC CONTROLS 'F'iled April 17, 1952 2 Sheets-Sheet 2 9 I (0' l g 36 K 7 /42 BY 5% fiAWL' F M 7 lrroewsKs Patented Mar. 23, 1954 CIRCUIT BREAKER WITH ADJUSTABLE THERMAL MAGNETICCQNTROLS Thomasv M. Cole,i Ha rrison, N. assignor to Federal Electric Products Gompany, Newark, N. J a corporation or Delaware Application April 17, 1952, Serial No, 282,819

This invention relates to circuit breakers in general'and, more: particularly, tocircuit break,- ers of the type which are manuallyoperable to open. or to close'the circuit and automatically operable to open the circuit upon. theoccurrence of' an overloadf or short circuitcondition.

One object of the. present invention is the provision of acircuit breaker having independently adjustable thermal and magnetic controls whereby to provide for the accurate calibration of'the circuitbreaker;

v Another object of the present invention i the provision ofimproved tripping means for an automatic circuit breaker. including a current responsive" bimetallic member adapted to effect opening of the'cir'cuit'breaker' upon moderate currentwoverload and magnetic elements, for e'fiectingmagnetic-tripping of the circuit breaker on/heavy current overloads and short circuits.

Another object of the present invention is the provision of tripping means of the-above character' which. is'simple andeconomical to manufacture'andefiectiveinoperation. l

i'Ihe above and other objects, features and advantages of the present invention will be more fully'understood from the following description considered inconnection with the accompanying illustrativedrawings.

" In the'drawings:

Fig; lls a top plan view of a multi-pole circuit breaker 'according to the present invention with the cover shownrremoved;

' Fig.2 isza secti nalview taken on the line 2-2 ofFig;1:;'

Fig; 3 is asectional view taken on the line 3'-3 Fig 1;

r Fig. 4 is a sectional view taken on the line 41-4 Fig. 5 isa sectional view taken on the line 5 5 OfFigil; t a

. Fig.' 6 is a. perspective view of the trip bar;

Fig. 7 is a view similar to Fig. l of a s n pole circuit breaker according to the present invention; Fig: 8 is a sectional view taken on. theline fi.;8 of;Fig.7;-

Fig. 9 is a sectional view taken on the. line 9 -.9.of Fig. '7;

r, Fig. 10 is, a sectional view taken onithe, line |-lDofFig.7;

Fig. 11 isa perspectivev view ofthe trip bar of the circuit breaker shown in Figs; 7-10; and

Fig. 12. is a. sectional view taken onthe line l 2-,---JTorrie.1'. 3'

j Rgefellflnggtfl the drawings; and; more particue 1 -Clai 1'ns. (01'. 200 938) larly, toFigs. 1 through 6 thereof, there is shown a circuit breaker of the multipole type, each pole comprisin a pair of terminals l2 and- I4, one disposed at each end of the breaker. The circuit breaker It includes a base It preferably of molded insulating material on which the several elements of'the breaker mechanism are mounted. A cover 18 also preferably of molded insulating material is removably secured to the base I6 and cooperates therewith to form an enclosing housing for the breaker mechanism. The circuit breaker H] is also provided with associated pairs of stationary contacts 20 and movablecontacts 22, and an arc extinguisher 24 of conventional construction. Each of the movable contacts 22 is'mounted on-a movable contact member 26, said movable contact members being movable to open and closed positions by the operating mechanism. indicated generally at 28. Thus the common operating mechanism Z8 is provided for simultaneously actuating the movable contacts 22 to open-and to.closed positions, there being provided a. trip device indicated generally at 3il for effecting the automatic opening of all of the movable contacts 22 in response to predetermined overload-conditions in the circuit through any pole of the-breaker. Each of the poles of the breaker is contained in. a separate compartment formed by barriers 32 which extend for the length of the breaker. It Will be understood that the barriersv 32 are in alignment with similar barriers in the cover, [8- so that when the cover is in place theE barriers serve to insulate each compartment from an adjacent compartment. Each of the movable contact members is pivotally mounted intermediate its ends for movement by the common operatin mechanism indicated generally at 28. Said common: operating mechanism may be of any -of the well-.knowntypes, for example, of the type shown in' Patent No. 2,419,125, issued Aprilr 15,1947, to I-Ieeler D. Dorfman and Gerald J. Freese, for-Circuit Breaker.

The circuit breaker I0 is provided with an externally accessible operating handle 34 which is movable to open and closed positions for movingthe contact members. 26 to corresponding positions. Operatively associated with the operating mechanism 28- isa cradle36 having an end portion-38 Which-is operatively associated with the trip device; 30 in a manner to be described in detail hereinafter. Thetrip device comprises atrip bar 40 having end shaft portions 42=which aremounted for rotation in the bearing portions 44 ofthe breaker. Thus theitrip bar is mounted for. rctationr about its longitudinal axis and. is

3 transversely mounted in the breaker. It will be seen that the trip bar 46 extends across the barrier 32, the latter being suitably recessed at 46 for the reception of a central portion of the trip bar. The trip bar 40 is provided with a laterally projecting portion 48 and a laterally depending portion 56 for each compartment, said projecting and depending portions being preferably formed integral with the trip bar. The trip bar 40 is notchedcentrally at 52, said notch being adapted to be positioned on adjacent portions of barrier 32 at recess 46, the rotation of the trip bar in a counter-clockwise direction as viewed in Figs. 2 and 3 being effective to release the cradle 36 for moving the contact members 26 to an open position. Positioned in each compartment is a thermally responsive bimetallic element 54, said element being secured at one end to the conductor 56 in any well known manner. At the free end of the element 54 there is threadedly received screw member 58 having at one face portion 66 a protuberance 62, the latter bein adapted to cooperate with the laterally projecting portion 48 of the trip bar 46. It will be seen that the rotation of the screw member 58 will be effective to axially move the latter whereby to vary the space between the protuberance 62 and adjacent portions of the face 64 of its associated projectin portion 46. As previously noted, each compartment is structurally and electrically similar and the operating mechanism disposed in each compartment is similarly structurally similar, except that one compartment will be provided with operating mechanism 26 for simultaneously actuating the contact members 26, one of which is disposed in each compartment. From the above, it will be seen that each compartment is provided with an element 54 and the space between the protuberance 62 and the associated projecting portion 46 may readily be adjusted by rotating the screw 58. Thus the positioning of the adjusting screw 58 will be effective to calibrate the position at which bar 46 will be tripped in response to a predetermined current in the associated circuit. It will be understood that a predetermined current in the circuit will be effective to flex the free end of element 54 towards the trip bar 40 and that the degree of flexing required for tripping bar 43 is adjusted by means of the axial positioning of the screw member 1 58. The element 54 is connected in series into its associated circuit whereby said element will be current responsive on a predetermined overload to rotate the trip bar in a counter-clockwise position as viewed in Figs. 2 and 3 to thereby release all of the contact members 26 simultaneously to an open position. The thermally responsive bimetallic element is adapted to trip the bar 40 after a time delay on predetermined overload conditions.

Adjustably secured to each of the depending portions 50 or trip bar 46 is an armature 66 which comprises a plate of magnetic material which has a face portion 66 in confronting position with the face 16 of the de ending portion 50. The armature 66 is adapted for lateral movement relative to the depending portion 56 by means of the adjusting screw element 12, the rotation of the latter being effective to move armature 66 inwardly and outwardly of the face 16 of the depending portion 50 to adjust the air gap in the instant apparatus, as will become apparent from the description which follows. Associated with each of the bimetallic elements 54, adjacent to the secured end thereof is a magnetic yoke 14 havin pole faces 16 in confronting relation relative to the armature 66. The magnetic yoke 14 is secured to the conductor 56 in any conventional manner, as by means of the rivets 18. Thus the element 54 and the magnetic yoke I4 are secured to the conductor 56 and said yoke 14 is positioned so as to be magnetically energized in accordance with the current in element 54. A previously pointed out, the element 54 is connected in series in its associated circuit whereby the magnetic yoke is similarly connected into said associated circuit. The air gap between the pole faces I6 of the magnetic yoke 14 and the armature 66 is adjusted by rotating the screw element I2, it being apparent that said rotation of the screw element will be effective to vary the distance between the armature 66 and the magnetic yoke 14. The armature 66 is adapted to be attracted to the magnetic yoke 14, instantaneously on overload currents of predetermined magnitude, said attraction being effective to rotate the trip bar 46 in a counter-clockwise direction as viewed in Figs. 2 and 3, to thereby release cradle 36 for simultaneously opening the contact members 26. The trip bar 46 is provided with a latch member 60 having a latch portion 82 which is adapted to cooperate with the portion 38 of cradle 36. With the cradle 36 in the latching position, as shown in Figs. 1, 2 and 6, the portion 36 will abut and be restrained against the underside of the latch portions 62. On overload conditions in the circuit breaker the trip bar 46 will be rotated in a counterclockwise direction, as aforedescribed, whereby the portion 38 of the cradle 36 will be released for clockwise rotation about itspivot 84 whereby the operating mechanism 28 will simultaneously open all of the companion contacts 20 and 22. More specifically, overload currents of a predetermined magnitude will instantly cause armature 66 to be attracted to the yoke 14 to thereby rotate the trip bar 46 in a counter-clockwise direction, the rotation of said trip bar bein effective to unlatch the cradle 36. Similarly,

lesser overloads after a time delay will cause the element 54 to flex towards the trip bar 46, said flexing movement causing the member 58 to move the projecting portion 48 whereby. to rotate the trip bar 43 in a counterclockwise direction, as aforedescribed, to thereby unlatch the latch portion 82 from the cradle 36. From the above, it will be seen that the screw member 58 for calibrating the thermal overload is independent of the adjustment element 12 for calibrating the magnetic overload whereby the circuit breaker [0 may be accurately calibrated,

The trip bar 46 is biased in a clockwise direction, as viewed in Figs. 2 and 3, by means ofthe spring 96 which is positioned in the recess 92 of partition 32, said spring having its end 94 operatively associated with the face portion 96 of the trip bar 60 whereby said spring will produce a biasing componentwhich will urge the trip bar 40 in the clockwise direction aforedescribed. It will be noted that the biasin of'the trip bar 46 in a clockwise direction will tend to urge the latch member 66 into a latched position whereby a positive overload condition is necessary for retating the trip bar in a counterclockwise direction to unlatch the cradle 36.

The electrical circuit for each of the poles is essentially the same and extends from the terminal l 2 through the conductor 56 and the bimetallic element 54, through the flexible wire I06 and through the contact member 26 having contact oneof aplurality of compartmentsdefined by The operating :mechanism 28 the barrier. 32. includes ,a forkedoperatinglever, I114; a toggle l;0,6,:.cQmDri$ing a pai-rof links, over centering springsI08 and areleasable cradle 36control1ed bath t ip. dev e. .0, afor deseribed- Th to ink ar pi ta l eonn et d together b the kneelpin a d said' e e links o e a conventional manner whereby the operating mechanism 28 is of the quick makeand break type. is here to be noted-that the operating mechanism 28 formsnO part of the present invention and accordingly onlya general description fofsaid operating mechanism is herein made. Thetie bar I. I2 which extends across all of the polesof the breakerextends through a suitable aperture in the barrier32, it being noted that each of the movable. contact members. 26 is connectedito thetie barIIZ'whereby the rotation of said tie bar will be effective to simultaneously actuate all of the movable contact members 26. Thetransversely extending tie bar I I2 is mounted for rotation in the. breaker II] in any desired manner and each of the, contact members 26 is secured thereto at. Spaced. points through the intermediationof thelinks, IIII, eachof said. links straddling itsassociated movable contaot memberj'26. The movement of the operating handle or lever. 34/is effective to correspondingly actuate, each of themovable contact members 26 Simulta ou l a i h e -shine of. the. tri bar 40in. response to a current overload in any poleof the trip devices 30 willbe effectiveto. open all of the circuitsofthe breaker as will be readily apparent. When the tr ip bar'4 0, islll latched in response to a current overload the cradle 36 will-snap to an unlatched position being rotated in a clockwise direction about its pivot 84, due to the --action-ofthe-springs I08. Thus on the release ofthe-cradle36it willbe rotated'in a clockwise direction as viewed in Fig. 2-by the spring I08 which will be tensioned with the cradle 38 inaa latching position. The-release of said'cradle will also result-in: the rotationof tiebar H2 in a.-.counter.clockwise direction viewing Fig. 2

whereby;each of the contact members 26 securede dffi? nes i sn fie es r evic the lever 341st rotated from its tripped position to its. extreme-counter-clockwise or on position, ,This movement-of the lever 3 A is, transmittedtto the radlewto rotat said cradle in a counter-clockwise;idirection, theendqportion: 3B.

ofesaidl cradle; passing theolatch portion. 82. of

thezlatchomembert BI]atoe inten-engagewith -said- 3:4;w illlube at a position; intermediate the on portion 82. Thus the movementof th'e cradle-3d,

will be effective to rock the trip bar 40 counterclockwise against the-biasing of spring slightly.

past its normal positionto thereby .relatch the cradle 36. After the cradle is so relatched the contacts can be closed manually by movingthe lever 34 clockwise to its closed circuit position. Aspreviously mentioned the operating mecha-.

nism-28 is preferably of thequick make and-break type in which the springs I03 actuate-the toggle mechanism to make. and break the circuit-with a positive snap action. The aforedescribedcircuit breaker is trip-free sothat it is operative automatically in response to predetermined abnormal circuit conditions in any one of the polesthereof irrespective ofthe position of the-operating lever 34. takes place in any of the'poles of the circuit breakerlb the trip bar 40 will release thecradle:

36 whereby each of thecontact-members 26 will be opened witha snap-action. Anarc extinguisher 2 is provided for each pole of the breaker Al-.' though the circuit breaker I0. is-of the=two-po1e-.

and isgenerally of the spaced plate type.

type it will be understoodthat the trip device 30 of the present invention is equally applicable to a single-pole circuit breaker as welllas to a multi-pole circuit breaker havingany numberof poles positioned in side-by-side-arrangedcome partments. Thus the trip-bar:40 aforedescribed is equally applicable to- -a circuit: breaker having:-

any number of poles. With-reference tonEigs. :7 through 11 there is shown-asingle-pole circuit breaker I0 which is structurally similar to circuit breaker Hl except that circuit breaker-I0" is of a single-pole type. The-circuit breaker I0 is provided with internal: structurewhich-is-substantially identical with the structure disposedin breaker it exceptfor the trip bar 40' now to be described. The trip bar .40 is provided with. a laterally projecting portion 48 Whichis. op-

eratively associated with the cradle 36' in the manner described in reference to breaker III.

The latch member I26 is adaptedto perform the. same function as latch member fill-of. breaker I0 and comprises a plate i22 which-is apertured at,

I24 for the reception of the portion.38' of the cradle 36. Thus trip bar 43 is structurally similar to trip bar' lfl except for the latch member.

I20 which is provided with aperture I24: through which extends the portion 38 of-cradle.36 in th latched position of the latter. It will beapparent from the above that the rotation of trip. bar '40: in response tov an overload current conditionwill be effective: to release the cradle -38-for.c1ockwise rotation in the manner described above. Thus trip bar. 40 differs from trip bar; II].v in the latch member which is operatively associated with the cradle 36. It will be seen fromthe above that the trip bar 40 is integrated with there-- mainder of the mechanism of breaker I0 in the An overload'condition in breaker III will causethe-trip bar- 40 to rotate in a counter-clockwise direction wherebythe. face I32-will assume the- Thus if an overload conditionposition I32 shown in Fig. 9. It is to be noted that the component of force produced by the curved end portion I30 of spring 128 is to the left of a line drawn from the center of the tri bar to the point of contact of the spring and face i152 whereby the trip bar will be normally springurged in a clockwise direction. Thus, except for the specific structural details afore-described circuit breaker I operates in a similar manner to the circuit breaker I0 whereby it will be seen that trip device 30 according to the present invention is applicable to a single pole breaker as well as to a multi-pole circuit breaker It will be seen from the above that the trip device 30 according to the present invention provides for thermal and magnetic overload controls which are each individually adjustable to actuate a common trip bar whereby to provide a circuit breaker which may be readily calibrated with a high degree of accuracy.

In order to apply contact pressure to the movable contact member 26 when the latter is closed, there is provided means for biasing said contact member in a clockwise direction, as viewed in Fig. 12. More particularly, the link member H4, which straddles the contact member 26, has an intermediate portion of said contact member pivotally mounted thereon by means of the pivot pin I40. As previously pointed out, link member H4 is secured to the tie bar H2 in any conventional manner, as by having said tie bar passed through a complementary aperture in said link member. The tie bar H2 is also provided with a strap element I46 which is secured to the bottom plate I48 of the link member i it in any suitable manner, said element being efiective to rigidly secure together the tie bar and said link member. Secured to the bottom plate M3 in any suitable manner is a plate member 652, said plate member having an end portion i54 which is operatively associated with portion Hit of member 26 to limit the pivotal movement of the latter member in a clockwise direction when the member 26 is in an open circuit condition. It is to be noted that the link member H 4 adjacent to its securement to the tie bar II2 is U-shaped in cross section and is provided with a base plate I48 which is adapted to receive spring I44 positioned between said base plate and the end portion I42 of the contact member 26. The contact member 26 is further provided with an integral extension I50 which is received in spring I44 for restraining said spring in position. The spring I44 is positioned as aforedescribed under tension whereby the contact member 26 will be spring urged in a circuit closing direction about its pivotal mounting Mil. Thus when the tie bar H2 is rotated in a circuit closing direction by the operating mechanism aforedescribed, the link member H4 will be com comitantly rotated to thereby move the movable contact member 26 in a circuit closing direction with the spring I44, applying contact pressure to said movable contact member when the latter is in a circuit closed condition. Thus the compression spring I44, which is associated with the contact member 26 in the manner aforedescribed, will apply a contact pressure between the companion contacts 20 and. 22 when the latter are in a circuit closed condition. It will be understood that each of the movable contact members 26 is structurally similar and is integrated with its tie bar H2 in a structurally similar manner.

ferred embodiments of my invention, it will be understood that various changes may be made in the present invention without departing fro..."

the underlying idea or principles of the invention within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is: 1. In a circuit breaker having stationary and movable contact members, mechanism for actuating said movable contact member to open and close the circuit breaker, and a trip device including a movable latching member for releasably holding said mechanism in contact-closing condition, control means for said trip device, comprising a bimetallic strip responsive to the current in the circuit, an adjustable member carried by said strip and operable to move with said latching member to a mechanism-releasing position in response to flexing of said strip when the current reaches a predetermined value for opening the circuit breaker, electro-magnetic means operable to move said latching member to a mechanism-releasing position when the current reaches a predetermined value, said electromagnetic means including a magnetic yoke disposed relative to said strip for energization by the current therein and an armature operatively connected to said latching member, and means operable independently of the strip for adjusting the air gap between said yoke and said armature.

2. In a circuit breaker having stationary and movable contact members, mechanism for actuating said movable contact member to open and close the circuit breaker, and a trip device including a movable latching member for releasably holding said mechanism in contact-closing condition, control means for said trip device, comprising a bimetallic strip responsive to the current in the circuit, an adjustable member carried by said strip and operable to move with said latching member to a mechanism-releasing posi- 'tion in response to flexing of said strip when the current reaches a predetermined value for opening the circuit breaker, electro-magnetic means operable to move said latching member to a mechanism-releasing position when the current reaches a predetermined value, said electro-magnetic means including a magnetic yoke disposed relative to said strip and energized by the current therein and an armature carried by said latching member and adjustably movable thereon in relation to said magnetic yoke for adjusting the air gap between said yoke and armature.

3. In a circuit breaker having stationary and movable contact members, mechanism for actuating said movable contact member to open and close the circuit breaker, and a trip device including a movable latching member for releasably holding said mechanism in contact-closing condition, control means for said trip device, comprising a bimetallic strip responsive to the current in the circuit, a member actuated by said strip and operable to move said latching member for moving the latter to a mechanism-releasing position in response to flexing of said strip when the current reaches a predetermined value for opening the circuit breaker, electro-magnetic means operable to move said latching member to a mechanism-releasing position when the current reaches a predetermined value, said electro-magnetic means including a magnetic yoke disposed relative to said strip and for energization by the current therein and an armature carried by said latching member and adjustably movable there- 9. on in relation to said magnetic yoke for adjusting theair gap between said yoke and armature.

4; In a circuit breaker having stationary and movable contact members, mechanism for actuating said movable contact member to open and close the circuit breaker, a trip device including a movable latching member for releasably holding said mechanism in contact-closing condition, control means for said trip device, comprising a bimetallic strip responsive to the current in the circuit, said strip being fixed at one end thereof and free to flex at its opposite end, said latching member being mounted independently of said strip, an adjustable screw member carried by said free end of the strip and operable upon said latching member for moving the latter to a mechanism-releasing position in response to flexing of said strip when the current reaches a predetermined value for opening the circuit breaker, electrc-iiagnetic means operable to'move said latching member to a mechanismreleasing position when the current reaches a predetermined value, said electro-magnetic means including a magnetic yoke disposed relative to said strip for energization by the current therein and an armature carried by said latching member and adjustably movable thereon in relation to said magnetic yoke for adjusting the air gap between said yoke and armature.

5. In a circuit breaker having stationary and movable contact members, mechanism for actuating said movable contact member to open and close the circuit breaker, and a trip device including a movable latching member for releas ably holding said mechanism in contact-closing condition, control means for said trip device, comprising thermal-current means and magnetic means individually responsive to the current in the circuit for individually actuating said latching member to mechanism-releasing position, in response to different current values, respectively, and including individually adjustable members operable individually by said thermal current means and by said magnetic means, respectively, for adjusting the response of said latching member in relation to the current values.

6. In a circuit breaker having stationary and movable contact members, mechanism for actuating said movable contact member to open and close the circuit breaker, and a trip device including a movable latching member for releasably holding said mechanism in contact-closing condition, control means for said trip device, comprising thermal-current means and magnetic means individually responsive to the current in the circuit for individually actuating said latching member to mechanism-releasing position, in response to different current values, respectively, and including individually adjustable members operable individually by said thermal current means and by said magnetic means, respectively, for adjusting the response of said latching memher in relation to the current values, said latching member including a trip bar mounted for pivotal movement about its own axis and having actuating arms disposed at opposite sides of said axis for turning the bar, one of said individually adjustable members being mounted on one of said arms and the other of said adjustable members being operable to movethe other of said arms.

7. In a circuit breaker having stationary and movable contact members, mechanism for actuating said movable contact member to open and close the circuit breaker, and a trip device lb including a movable latching member for releasably holding said mechanism in contact-closing condition, control means for said trip device, comprising thermal-current means and magnetic means individually responsive to the current in the circuit for individually actuating said latch- 7 ing member to mechanism-releasing position, in

response to diilerent current values, respectively, and including individually adjustable members operable individually by said thermal current means and by said magnetic means, respectively, for adjusting the response of said latching memher in relation to the current values, said latching member including a trip bar mounted for pivotal movement about its own axis and having actuating arms disposed at opposite sides of said axis for turning the bar, one of said individually adjustable members being mounted on one of said arms and the other of said adjustable members being operable to move the other of said arms, said thermal-current means including a bimetallic strip on which said other of the adjustable members is mounted and which flexes toward said other arm, in response to a predetermined current value, for operating said arm to move said latching member to mechanismreleasing position.

8. In a circuit breaker having stationary and movable contact members, mechanism for actuating said movable contact member to open and close the circuit breaker, and a trip device including a movable latching member for releasably holding said mechanism in contact-closing condition, control means for said trip device, comprising thermal-current means and magnetic means individually responsive to the current in the circuit for individually actuating said latching member to mechanism-releasing position, in response to different current values, respectively, and including individually adjustable members operable individually by said thermal current means and by said magnetic means, respectively, for adjusting the response of said latching member in relation to the current values, said latching member including a trip bar mounted for pivotal movement about its own axis and having actuating arms disposed at opposite sides of said axis for turning the bar, one of said individually adjustable members being operable to move one of said arms and the other of said adjustable members being operable to move the other of said arms, said individually adjustable members being positioned in relation to said arms, respectively, so that both arms move in the same rotary direction when operated by said individual members, respectively.

9. In a circuit breaker having stationary and movable contact members, mechanism for actuating said movable contact member to open and close the circuit breaker, and a trip device including a movable latching member for releasably holding said mechanism in contact-closing condition, control means for said trip device, comprising thermal-current means and magnetic means individually responsive to the current in the circuit for individually actuating said latching membar to mechanism-releasing position, in response to different current values, respectively, and including individually adjustable members operable individually by said thermal current means and by said magnetic means, respectively, for adjustting the response of said latching member in relation to the current values, said latching member including a trip bar mounted for pivotal movement about its own axis and having actuating arms disposed at opposite sides of said axis for turning the bar, one of said individually adjustable members being operable to move one of said arms and the other of said adjustable members being operable to move the otherol said arms, said individually adjustable members being positioned in relation to said arms, respectively, so that both arms move in the same rotary direction when operated by said individual members, respectively, said thermal-current means including a bimetallic strip arranged to be responsive to the current in the circuit controlled by the circuit breaker, and said magnetic means including a magnetic yoke energized by the current in said strip.

10. In a circuit breaker having stationary and movable contact members, mechanism for actuating said movable contact member to open and close the circuit breaker, and a trip device including a movable latching member for releasably holding said mechanism in contact-closing condition, control means for said trip device, comprising thermal-current means and magnetic means individually responsive to the current in the circuit for individually actuating said latching member to mechanism-releasing position, in response to different current values, respectively, and including individually adjustable members operable individually by said thermal current means and by said ma netic means, res ectively, for adjusting the response of said latching member in relation to the current values, said latching member including a trip bar mounted for pivotal movement about its own axis and having actuating arms disposed at o posite sides of said axis for turning the bar, one of said individually adjustable membe s bein operable to m ve one of said arms and the other of said ad ustable members being operable to move the other of said arms. said individually adiustable members being positioned in relation to said arms, respectively, so that both arms move in the same direction when ope ated, by aid in v ua m rs. respectively. said thermal-current means includine a bimeta lic strip arranged to be res onsive to the current in the circuit controlled by the circuit breaker. and said ma netic means includin a magnetic yoke ener ized by the current in said strippone of said ad ustable members having an armature carr ed thereby in position to be attracted by said ma netic yoke when the current in the strip reaches a predetermined value.

11.. In a circuit breaker havin stationary and movable contact members. mechanism for actuating said movable contact member to open and close the circuit breaker. and a trip device ncluda movable latching member for releasably holdin said mechanism in contact-closing condition, control means for said trio device, comprising thermal-current means and ma netic means individually res onsive to the current in the circuit for individually actuat n said latchin member to mechanism-releasing position. in response to different current values, respectively, and including individually ad ustable members operable individually by said thermal current means and by said magnetic means, respectively, for adjust ing the response of said latching member in relation to the current values, said latching member including a trip bar mounted for pivotal movement about its own axis and having actuating arms disposed at opposite sides of said axis for turning the bar, one of said individually adjustable members being operable to move one of said arms and the other of said adjustable, members 12 being operable to move the other of said arms, said individually adjustable members being positioned in relation to said arms, respectively, so that both arms move in the same rotary direction when operated by said individual members, respectively, said thermal-current means including a bimetallic strip having its low expansion side facing said trip bar so as to flex toward the latter when heated for actuating one of said individually adjustable members for operating one of said arms, and said magnetic means including a magnetic yoke facing toward the other of said individually adjustable members for attracting the latter when the current reaches a predetermined value.

12. In a circuit breaker having stationary and movable contact members, manually operable trip-free mechanism for effecting engagement and disengagement of said contacts, automatically operable means associated with said mechanism for actuating the latter to disengage said contacts, comprising a trip device including a latching member normally releasably connected operatively with a part of said mechanism and releasable from said part upon actuation of said trip device to disengage said contacts, thermal control means for actuating said latching mem' ber directly to release said part of said mechanism, and magnetic control means for actuating said latching member directly to release said part of said mechanism, said thermal control means and said magnetic control means being individually adiustable independently of each other for calibrating the circuit breaker for automatic operations in response to different current values under the control of said thermal means and said magnetic means, respectively.

13. In a circuit breaker, a stationary contact member, a movable contact member engageable with and disengageable from said stationary contact member, mechanism for operating said movable contact member to engage and disengage said stationary contact member, said mechanism including a link member, means mounting said movable contact member directly on said link in pivotal relation thereto whereby said movable contact member is bodily movable directly with said link member when said mechanism is actuated for said operation of said movable contact member and spring means engaging directly said link and said movable contact member for resiliently moving said movable contact member directly in relation to said link for providing contact pressure when said movable contact member engages said stationary contact member.

14. In a circuit breaker, a stationary contact member, a movable contact member engageable with and disengageable from said stationary contact member, mechanism for operating said movable contact member to engage and disengage said stationary contact member, said mechanism including a link member, means mounting said movable contact member directly on said link in pivotal relation thereto whereby said movable contact member is bodily movable directly with said link member when said mechanism is actuated for said operation of said movable contact member, and spring means engaging directly said link and said movable contact member for resiliently moving said movable contact member directly in relation to said link for providing contact pressure when said movable contact member engages said stationary contact member, said link member having laterally spaced side arms between which said movable contact member is positioned, spring means being disposed between said side arms and said movable contact member having an end portion against which said spring means exerts pressure for said resilient movement of said movable contact member in relation to said link.

15. In a circuit breaker having stationary and movable contact members, mechanism for actuating said movable contact member to open and close the circuit breaker, and a trip device including a, pivoted trip bar having an arm provided with a latching member for releasably holding said mechanism in contact-closing condition, said bar having a second arm for pivotally moving said trip bar to move said latching member to mechanism-releasing position, and electromagnetic means for moving said second arm to effect said movement of the trip bar, said magl4 netic means comprising a magnetic yoke and a companion armature, means mounting said armature on said second arm for attraction by said yoke when the latter is energized, said mounting means having provision for adjusting said armature in relation to said yoke for adjustably varying the air gap between said yoke and said armature.

THOMAS M. COLE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,325,717 Swingle Aug. 3, 1943 2,573,306 Casey Oct. 30, 1951 2,573,307 Casey Oct. 30, 1951

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