US2094966A - Automatic circuit breaker - Google Patents

Description

Oct. 5, 1937. J. sAcHs AUTOMATIC CIRCUIT BREAKER 5 Sheets-Sheet l El w on N

Original Filed Jan. 3, 1936 NRM@ .FHI/Erft @f7 :f sEJUf/)a 5275 @y d.

A @it Urnfy Oct. 5, 1937. J. sAcHs AUTOMATIC C IRCUI T BREAKER Original Filed Jan. 5,. 1936 3 Sheets-Sheet 2 tf: arng/ oct. 5, 1937; 1 SACHS I 2,094,966

AUTOMATIC CIRCUIT BREAKER Original Filed Jan.- 5, 1936 3 Sheets-Sheet 5 .Patented Oct. 5, 1937 UNITED STATES PATENT OFFICE Application January 3*,

1936, serial No. 57,389

Renewed April 20, 1937 15 Claims.

vThe invention relates particularly to a circuit breaker of the general type disclosed in my copending application for Automatic circuit breakers, Serial No. 57,388 led January 3, 1936. In

such a circuit breaker the circuit may be opened by the manipulation of a handle or other operating member, or may be opened automatically independently of the operating member upon the attainment of excess or vother abnormal current pendently of the operating member and independently of the current conditions in the circuit. One of the objects of the invention is to provide a circuit breaker of this type wherein the means for mechanically opening the circuit independently oi' the operating member is controlled by the current responsive means and is supported independently of the operating member and independently of certain other parts as will presently be set forth.

While the` invention is applicable in a number of ways it is particularly applicable to an automatic circuit breaker of the multi-polar type wherein there are independently acting circuit breaker mechanisms in two or more legs of the circuit; and it is a further object of the invention to provide in a circuit breaker of this type improved means whereby the mechanism in one leg of the circuit serves upon automatic opening to effect the opening of the mechanism in each other leg of the circuit.

A further object of the invention is to provide a circuit breaker having a plurality of circuit breaking units for the diiierent legs oi the circuit, and wherein the several units are detachable and replaceable independently of each other.

Further objects of the invention will be apparent from the following specification and claims:

A multi-polar circuit breaker has been shown in the drawings as illustrating the invention, but it will be understood that the invention in its broader aspects is not so limited. The particular form of multi-polar circuit breaker shown is only one of several possible embodiments of the more specific phases of the invention and is to be regarded as merely representative or typical. The drawings are not to be relied upon as dening or limitingthe scope of the invention, the claimsv forming a part of this specication being relied upon for that purpose.

Of the drawings:

Fig. 1 is a. front view of an automatic circuit breaker embodying the invention, the enclosing casing being omitted. In this view the front conditions, or may be opened mechanically inde-4 (Cl. 20D-116) cover and vented insulating block of one of the units are omitted.

Fig. 2 is a bottom view of the parts shown in Fig. 1, this view showing a portion of the enclosing casing in transverse section.

Fig. 3 is a longitudinal sectional view taken along the line 3-3 of-Fig. 2 and showing the movable parts in their closed-circuit positions. Fig. 4 is a longitudinal sectional view taken along vthe line 4--4 of Fig. 2 and showing the contact member of one circuit breaker mechanism in an intermediate position, it being assumed that the said member has been automatically released and is moving toward its open-circuit position.

Fig. 5 is a view similar to Fig. 4 but showing the contact member in its full open-circuit position and also showing the connecting parts in the positions which they occupy when the operating .member is held in its closed-circuit position.

Fig. 6 is a view similar to Fig. 5 but showing the connecting parts and the operating member in their open-circuit positions.

The circuit breaker as shown in the drawings comprises three circuit opening and closing mechanisms connectible in three legs of a circuit. It will be understood, however, that I do not limit myself to this exact number of mechanisms and that only two or more than three mechanisms may be provided when required. In fact, as concerns certain phases of the invention only one mechanism'is necessary. The three mechanisms shown are similar in construction, and in conjunction with the common operating mechanism each may be regarded as embodying the invention in its broader aspects. Each of the said mechanisms is in many respects similar to that shown and described in my patent for Automatic circuit breaker No. 2,020,333 dated November 12, 1935. While a mechanism of the particular type yshown in the said patent is well suited for use in a circuit vbreaker embodying the present invention, I do not necessarily so limit myself.

I prefer and have shown in the drawings a circuit breaker wherein each circuit breaker mechanism is a separate self-contained unit. 'I'he several units are readily detachably mounted on a suitable support which may be a metal plate I. As shown this plate I is suitably secured to the rear wall of an enclosing cabinet 2 having an openable front cover 3.

A description of one of the circuit breaker mechanisms or units will suflice for all, and the following description will relate chiefly to the mechanism at the right as viewed in Figs. 1.

and 2. In the drawings the letter a will be added to the reference numbers to designate corresponding parts in the unit at the center, and the letter b will be added to the reference numbers to designate the corresponding parts of the unit at the left. 4

Each unit has a main insulating base d which carries all of the other parts of the unit. YFitting the base 4 at the front thereof is an insulating cover 5. The base il has a mechanism containing recess 6 therein, which is substantially closed at all four sides and at the bottom. The bottom wall of the recess is in the form of a removable insulating block 6' which is vented to permit the escape of arc formed gases as explained in my said patent. The block at the right is omitted in Fig. 1. The front coverhas a recess open at the bottom' into which certain parts of the mechanism project. When the two parts d and 5 are assembled'as shown, the recesses register and provide an interior chamber which contains all of the operative parts of the circuit 'breaker mechanism other than the intermediate operating member.

Carried by the base d near the front thereof and adjacent the recess dare two forward projecting parallel metallic plates l, 'I which are held in place by means of screws 8, 8 embedded in the walls of the base. The plates ll, l are provided with integral rearward extending portions 9, 3. Carried by the said rearward extensions 9, S and extending transversely between them is a pivot pin Il?.

The circuit breaker mechanism has a contact carrying member which is mounted on the pivot pin l@ and includes two parallel plates I I, II spaced apart transversely and suitably connected together to move as a unit. These plates have aligned bearing apertures through which the pivot pin extends. Suitable spacing washers, not shown, hold the plates in proper spaced relationship to the supporting plate extensions 9, 9.

The two plates II, II serve to carry the main movable circuit breaker contacts I2 and I3 of the circuit breaker which are arranged in tandem, being spaced apart in the direction of movement, that is, circumferentially. Preferably and as will be clearly apparent from an examination of Figs. 1 and 2, each movable contact I2 and I3 extends from one to the` other of the two plates II, II and is in direct engagement with both of them. Each of the said plates I I is provided with a hole and a notch, as shown in Fig. 3, adapted to receive turally separate from thel plates and held in proper relationship by means of the tie rods or Arivets I6 and I1 extending through suitable holes.

It will be apparent that the insulating members I4 and I5 extend transversely from the plate tov plate and that the movable contact I2 extends through the space between the two members. The member I5 engages with both movable contacts and extends circumferentially from one to the other. The two plates II' together with the `cover 5, the opening being of suilicient parts which mechanically connect them and together with the contacts which they carry, will for the sake of convenience be herein referred to collectively as a, contact member.

` 'Ihe two movable contacts I2 and I3 are electrically connected with each other, this electrical connection preferably being through an electroresponsive device which `is carried by and is bodily movable with the contact member. By preference and as shown, this electro-responsive device is a bi-metallic thermostatic strip I8 mechanically and electrically connected directly with one of the contacts, as for instance the contact I2. The strip I8 is provided at its projectinga end with an aperture I9 which enables the strip to serve as a latch as will be presently explained.

In order to complete the electrical connection between the two contacts I2 and i3 there is provided a suitable flexing or flexible connection 2li between the strip IB and the contact I3. This flexing connection is connected to thev strip by means of a yoke 2l and is sufciently ilexible to permit the bi-metallic strip I8 to freely deflect or bend under the influence of heat.

Carried by the insulating base l are two substantially stationary main contacts 22 and 23 which are connected with the said base by means of more or less resilient conducting straps 24 and 25, which may be supplemented by flexible conductors 26 and 2l.

These stationary contacts 22A can be rmly engaged respectively by the two movable contacts I2 and I3 as clearly shown in Fig. 3. The resilient strap 2li and the conductors 23 are carried by the base I and are connected with a wire terminal 28. The resilient strap 2G and the conductors 2l are carried by the base and are connected with a wire terminal 29.

From the foregoing description it will be apparent that pivotal movement of the contact member serves to bring the movable contacts I2 and I3 into or out of engagement with the respective stationary contacts 22 and 23 to make or break the circuit. When the parts are in the contact engaging position, as shown in Fig. 3 electrical connection is established between the terminal 28 and the terminal 29. A suitable spring 30 is provided for biasing the contact member in the contact disengaging or circuitopening direction.

For operating the circuit breaker mechanism there is provided a member 3| which will be designated as an intermediate member. 'Ihis intermediate member is mounted on a pin 32 extending transversely between the supporting plates 7, '1.v The intermediate member projects through an opening in the front wall of the front permit the necessary movement.

Interposed inthe operative connection between the intermediate member 3 I and the contact member is an actuating memberor actuator 33 of bell-crank form. The actuator is normally engaged by the thermostatic strip or latch I8, and the actuator is `so positioned and connected that a portion of the stress of actuation is transmitted directly from the actuator to the contact member independently of the thermostatic latch. The actuator 33 is pivotally mounted on a pin 34 extending transversely between the two side plates II, II and is held by two spacing bushings. The actuator is provided with a pointed end which, at normal temperatures, is entered in the aperture I9 in the thermostatic latch I 8. With the parts in the relative positions shown in Figs. 3, 5 and length to i 6, the actuator and the contact member are positively connected to move in unison.

The intermediate member 3| is connected with the actuator 33 by means of a pivoted link 35. The link 35 does not move into toggling relationship with the intermediate member 3 I this being prevented by a stop 3| which engages the member-3|.

When there are two or more circuit breaker units as shown, they are mounted side by side on the common support I and their intermediate members 3|, 3| and 3|b are connected together for movement in unison. The several intermediate members will be referred to collectively as intermediate means.

For moving the intermediate means and thereby moving the contact members to open or close the circuit, there is provided a handle or operating member 36. As shown, this operating member 36 is rigidly secured to a transverse shaft 31 which is mounted in suitable bearing apertures in sheet metal brackets 38, 33, preferably formed integrally with the sheet metal supporting plate I. The operating member 36 is so positioned that its forward portion projects through a suitable aperture in the front cover 3 of the cabinet. A spring '33 serves to bias the operating member for movement toward its open-circuit position as shown in Fig. 6.

A normally operative mechanical connection is interposed between the operating member 36 and the intermediate means 3 I, 3 I a and 3 Ib, this operative connection being adapted to be rendered ineiective so as to permit the intermediate means and the contact members connected therewith to move to their open-circuit positions independently of the operating member. This operative connection preferably is of the triple toggle type. As shown, one link consists of a lever 40 rigidly secured to the shaft 31. Another link consists of a yoke 4| having a plurality ofarms which are detachably pivoted to the several intermediate members 3|, 3 |a and 3Ib, as for instance by means of pivot studs 42, 42EL and 42h, which may be regarded as constituting a part of the link 4|. The yoke 4I has a downward extending arm 4|'. A link 43 is pivotally connected with the arm 4|' at 44 and is pivotally connected to the arm 40 at 45. A spring 46 tends to hold the two links 4| and 43 in their toggle or locking relationship as shown in Fig. 3.

It will be observed that when the parts are in the closed-circuit positions shown in Fig. 3, the pivotal axes at 44 and 45 are behind a straight line connecting the pivotal axes at 42 and 31, the triple toggle linkage thus resisting the tendency of the intermediate members and the contact members to move to their open-circuit positions under the influence of the springs 30.

The toggle action also resists the tendency of the handle or operating member 36 to move to its open-circuit position under the influence of gravity and under the influence of the spring 33.

The circuit can be broken in all of the legs thereof by manually moving the handle or operating member 36 from its upper position as shown in Fig. 3 to its lower position as shown in Fig. 6; and the circuit can be closed by moving the operating member from the position shown in Fig. 6 to the position shown in Fig. 3. During such opening and closing movements the two links 4| and 43 remain in their toggle or locking relationship and the bi-metallic latches I8 remain in engagement with the actuators 33.

As already explained, the bi-metallic strip I8 is electrically connected between the contacts I2 and I3. It is adapted to be deected rearward or radially outward upon the passage of excess current therethrough, with the result that the apertured portion I9 is disengaged from the end of the actuator 33. This leaves the actuator iree to turn, and the actuator therefore no longer holds the contact member in the closed-circuit position against the influence of the spring. The contact member therefore moves toward its open-circuit position as shown in Fig. 4. It will be observed that this automatic circuit-opening movement of each contact member takes place independently of each other contact member and also independently of the intermediate member and of the 'operating member.

In accordance with the invention, I provide a means which is dependent upon the operation of any one of the electroresponsive devices and which thereupon serves to release the holding means for the intermediate means and thus permit the intermediate means and each remaining contact member to move to their open-circuit positions. The: last said means may be varied as to mechanical structure but as shown it is constructed to be actuated by any one of the contact members when such member approaches its open- `circuit position. The said means includes a transverse bar 41 which is positioned at the front of the circuit breaker units and immediately behind the pivotal connection at 44 between the links 4| and 43. The bar 41 is supported and guided for forward and backward movement by means'of arms 48, 48 loosely pivoted on the shaft 31. Carried by the front cover 5, of each circuit breaker mechanism is a movable slide 49. Each slide 49 is immediately behind the transverse bar 41 and is guided for forward and backward move ment in a suitable aperture in the front cover. Each slide 49 is so positioned as to be adapted to be engaged by a suitable transverse rod 50 extending between the two side plates II, |I of the corresponding contact member.

When any one of the circuit breaker mecha' nisms, as for instance the mechanism at the right, is automatically operated by reason of abnormal current conditions, the contact member thereof moves in the clockwise direction and the cross bar 50 engages\the corresponding slide 49 as shown in Fig. 4. Continued movement of the Contact member to its complete open-circuit position causes the slide 49 to be moved forward to the position shown in Fig. 5 and the slide 49 in so moving moves the cross bar 41 to the position shown in the same gure. Inasmuch as the cross bar 41 is behind the pivotal connection at 44, the pivotal connection is moved forward in opposition to the spring 4B. The breaking of the toggle relationship of the links 4| and 43 permits the intermediate members 3|, 3|u and 3|b and the remaining contact members to move to their open-circuit positions under the inuence of the remaining springs biasing such contact members. It will be observed that the automatic operation of one circuit breaker mechanism thus serves to automatically cause the operation of the other circuit breaker mechanisms.

' 'I'he movement of the intermediate member 3| to its open-circuit position as shown in Fig. 5 restores the actuator 33 to its normal latching relationship with the latch I8 and relatching automatically occurs.

It will be observed that the automatic operation of all of the circuit breaker mechanisms oocurs independently of the handle or operating member 33t. This will be clear from an inspection of Fig. 5, it being assumed that the operating member 36 has been held in its closed-circuit position as there shown. However, if the operating member is not held in its closed-circuit position, or if it be first held and then released, the operating member will move to its open-circuit position as shown in Fig. 6 under the inuence of gravity and under the influence of the spring 39. This movement of the operating member to its opencircuit position permits the links @il and 63 to again assume their locking relationship under the influence of thespring 66 as shown in Fig. 6. As already stated, the circuit can then be closed by moving the operating member 36 upward and thus moving all of the parts from the positions shown in Fig. 6 to the positions shown Ain Fig. 3. If the handle be held in its closed-circuit position and ifA all of the electro-responsive devices operate simultaneously, there would then be nothing to move the intermediate members out of the position shown in Figs. 3 and 4. However, upon release of the handle, the handle spring 39, supplemented by gravity, would move the several parts to the relative positions shown in Fig. 6 and relatching would thereupon occur.

While I do not necessarilyl so limit myself, I prefer to construct the several circuit breaker mechanisms as separate detachable units such as have already been described. Each of the units is detachably connected with the rear supporting plate l by means of screws such as Eile, l and Sib, Sib. As already stated,v the intermediate members of the several mechanisms are detachably connected with the operating mechanisms, as

-for instance by means of the studs 52, 62a and d2".

It will therefore be apparent that any one of the units can be readily removed independently of any other unit for inspection, adjustment, repair or replacement. By providing one or more spare units the circuit breaker as a whole can be kept in service even though s'ome dimculty may arise in connection with one or more units.` The invention in its broader aspects is not necessarily limited to a plurality of independently movablev contact members. It will be observed that there is associated with each movable contact member a movable operating member and also a movable intermediate member. Two separate mechanical connections are provided, one between the contact member and the intermediate member and one f between the intermediate member and the oped to mechanically engage the other mechanical' connection to render it ineiective. ASpecifically and as illustrated, the said independently supported means includes the slide i9 and the transverse rod 56 with its supporting arms d6, t8.

As concerns the feature last above described, a circuit breaker embodying the present invention is readily distinguishable from a circuit breaker embodying the invention set forth in my co-pending application Serial No. 57,388. In the strucw ture of the co-pending application the mechanical `connection between the operating member and Each of these mechanical conthe intermediate or actuating member is released or rendered ineiective by its own biasing spring as soon as the corresponding electro-responsive device operates; but in the present structure the connection between the operating member 36 and the intermediate member 3l is not released by spring` action but on the contrary is released by reason of the independently supported elements i9 and 50 as already explained.

What I claim is:

1. In an automatic circuit breaker, the combination of a movable operating member, a movable intermediate member, a movable contact member,

a mechanical connection normally operative to enable the intermediate member to move the contact member to' open or close the circuit and adapted to be rendered ineffective so as to permit the contact member to. move to its open-circuit position independently of the intermediate member, a second mechanical connection normally operative to enable the operating member to move the intermediate member and adapted to be rendered ineffective so as to permit the intermediate member tomove to its open-circuit position independently of the operating member, one of the said mechanical connections including an electro-responsive device which automatically renders it ineective upon the attainment of abnormal current conditions in the circuit, and means supported independently of any of the aforesaid members and actuated upon the operation of the electro-responsive device in one mechanical connection and serving when so actuated to mechanically engage the Vother mechanical connection to render it ineffective.

2. In an automatic circuit breaker, the com bination of a movable operating member, a movable intermediate member, a movable contact member biased toward its open-circuit position, a mechanical connection normally operative to enable the intermediate member to move the contact member to open or close the circuit which mechanical connection includes an electro-responsive device automatically releasable upon the attainment of abnormal current vconditions "in the circuit to permit independent circuit-opening movement of the contact member, a normally operative mechanical connection between the operating member and the intermediate member adapted to be rendered ineiective so as to permit the intermediatemember and the contact member to move to 'their open-circuit positions independently of the operating member, and means supported independently of any of the aforesaid members and actuated upon the operation of the electro-responsive device in the first said mechanical connection and serving when so actuated to mechanically engage the second said mechanical connection to render it ineiective. l

3. In an automatic circuit breaker, the combination of a movable operating member, a movable intermediate member, a movable contact member biased toward its open-circuit position, a mechanical `connection normally operative to enable the intermediate member to move the contact member to open or close the circuit which mechanical connection includes an electro-rel sponsive device automaticallgreleasable upon theA attainment of abnormal current conditions in the circuit to permit independent circuit-opening movement of the contact member, a normally op- A erative mechanical connection between the operating member and the intermediate member and adapted to be rendered `ineffective so as to permit the intermediate member and the contact member to move to their open-circuit positions independently of the operating member, means supported independently of any of the aforesaid members and actuated upon the operation of the electro-responsive device in the first said mechanical connection and serving when so actuated to mechanically engage the second said mechanical connection to render it ineffective, and means automatically operable to move the intermediate member to its open-circuit position upon the rendering ineffective of the second said mechanical connection.

4. In an automatic circuit breaker, -the combination of a movable operating member biased toward its open-circuit position, a movable intermediate member, a movable contact member biased toward its open-circuit position, a mechanical connection normally operative to enable the intermediate member to move the contact member to open or close the circuit which mechanical connection includes an electro-responsive device automatically releasable upon the attainment of abnormal current conditions in the circuit to permit independent circuit-opening movement of the contact member, two toggle links normally in toggle relationship and mechanically connecting the operating member with the intermediate member to enable the former to move the latter, the said two links being also normally in toggle relationship with the operating member so that the latter is normally held in its closed-circuit position, and means supported independently of any of the said members and actuated upon the operation of the said electroresponsive device for moving the said two links out of toggle relation With each other to enable the actuating memberto move to its open-circuit position independently of the operating member and also to enable the operating member to automatically move to its open-circuit position.

5. In an automatic circuit breaker, the combinatlon of a movable intermediate means, a plurality of independently movable contact members each biased toward its open-circuit position, the said contact members having contacts respectively connectible in different legs of the circuit, a

plurality oi mechanical connections normally.

operative to enable the intermediate means to move the severalcontact members to open or close the circuit each of which mechanical connections includes an electro-responsive device automatically releasable upon the attainment of abnormal current conditions in the corresponding leg ofthe circuit to permit independent circuit-opening movement of the corresponding contact member, a device normally operative to hold the intermediate means in its closed-circuit position but adapted to be rendered ineiective so as topermit the intermediate means and the several contact members to move to their opencircuit positions, and means actuated upon the operation of the electro-responsive device in any one of the said mechanical connections and serving when so actuated to mechanically engage the said holding device to render it ineffective, the last said means being supported independently of the holding device and also independently of either the intermediate means or the contact members.

6. In an automatic circuit breaker, the combination of a movable operating member, a movable intermediate means normally operatively connected with the operating member, a plurality of independently movable contact members biased toward their open-circuit positions, a plurality of mechanical connections normally operative to enable the intermediate means to move the respective contact members to open or close the circuit, each mechanical connection including an electro-responsively controlled device automatically releasable upon the attainment of abnormal current conditions in the circuit to permit automatic circuit-opening movement of the corresponding contact member independently of the intermediate means and independently of any other contact member, a releasable means separate from the said mechanical connectionsy with the contact members for normally holding the intermediate means in its closed-circuit position, and means dependent upon the operation of the electro-responsively controlled device associated with any one of the said contact members and serving to release the said holding means and thus permit the intermediate means and each remaining contact member to move to their opencircuit positions.

7. In an automatic circuit breaker, the combination of a movable operating member, a movable intermediate means normally operatively connected with the operating member, a plurality of independently movable contact members biased toward their open-circuit positions, a plurality of mechanical connections normally operative to enable the intermediate means to move the -respective contact members to open or close the circuit, each mechanical connection including an electro-responsively controlled device automatically releasable upon the attainment of abnormal current conditions in the circuit to permit automatic circuit-opening movement of the corresponding contact member independently of the intermediate means and independently of any other contact member, a releasable means separate from the said mechanical connections with the Contact members for normally holding the intermediate means in its closed-circuit position, and means adapted to be actuatedby any one of the contact members upon independent circuitopening movement thereof and serving upon being soactuated to release the said holding means and permit the intermediate means and each remaining contact member to move to their opencircuit positions.

8. In an automatic circuit breaker, the combil nation of a movable operating` member, a movable intermediate means, a plurality of independently movable contact members biased toward their open-circuit positions, a plurality of mechanical connections normally operative to enable the intermediate means to move the respective contact members to open or close the circuit, each mechanical connection including an electroresponsively controlled device automatically releasable upon the attainment of abnormal current conditions in the circuit to permit automatic circuit-opening movement of the corresponding contact member independently of the intermediate means and independently of any other contact member, a releasable means operatively connecting the operating member with the intermediate means, and means dependent upon the operation of the electro-responsively controlled device associated with any one of the said contact members and serving to release the last said releasable means and thus permit the intermediate means and each remaining contact member to move to their open-circuit positions independently of the operating member.

9. In an automatic circuit breaker, the combination oi a. movable operating member biased toward its open-circuit position, a movable intermediate means, a plurality of independently movable contact-members biased toward their open-circuit positions, a plurality of mechanical connections normally operative to enable the intermediate means to move the respective contact members to open or close the circuit, each mechanical co-nnection including an electro-responsively controlled device automatically releasable upon the attainment of abnormal current conditions inl the circuit to permit automatic circuit-opening movement of the corresponding contact member independently of the intermediate means and independently of any other contact member, a releasable means operatively connecting the operating member'with the intermediate means and normally holding both of them in their closed-circuit positions, and means dependent upon the operation of the electro-responsively controlled device associated With any one of the said contact members and serving to release the last said releasable means and thus permit the operating member and the intermediate means and each remaining contact member to move to their open-circuit positions.

10. In an automatic circuit breaker, the combination of a movable operating member biased toward its open-circuit position, a movable intermediate means, a plurality of independently movable contact membersbiased toward their open-circuit positions, a plurality of mechanical connectio-ns normally operative to enable the intermediate means to move the respective contact members to open or close the circuit, each mechanical connection including an electro-responsively controlled device automatically releasable upon the attainment of abnormal current conditions in the circuit to permit automatic circuitopening movement of the corresponding contact member independentlyof the intermediate means and independently of any other contact member, a releasable means of the triple toggle type operatively connecting the operating member with the intermediate means and serving when the links are in locking relationship to hold bothA of them in their closed-circuit positions, and means dependent upon the operation of the electroresponsively controlled device associated with any one of the said contact members and serving to break the toggle relationship between two of the links and thus permit the intermediate means and each remaining contact member to move to their open-circuit positions independently of thel operating member which is also free to move to its closed-circuit position.

11. In an automatic circuit breaker, the combination of a movable operating member, a. movable intermediate means normally operatively connected with the operating member, a plurality of independently movable contact members having contacts respectively connectible in diierent legs of the circuit, a plurality of mechanical connections normally operative to enable `the intermediate means to move all of the contact members in unison to open or close the circuit, each mechanical connection including an electroresponsive latch bodily movable with the corresponding Contact member and automatically releasable upon the attainment of abnormal current conditions in the corresponding leg of the circuit to permit automatic circuit-opening movement of the corresponding contact member independently of the intermediate means and independently of any other contact member, a releasable means separate from the said mechaniaoeaeee cal connections with the contact members for l normally holding the intermediate means in its closed-circuit position, and means adapted to be actuated by any one of the contact members upon independent circuit-opening movement .5 thereof and serving upon being so actuated to release the said holding means and permit the intermediate means and each remaining contact member to move to their open-circuit positions.

12. In an automatic circuit breaker, the com- 10 bination oi' a movable operating member, a movable intermediate means, a plurality of independently movable contact members connectible in different legs of the circuit, a plurality of mechanical connections normally operative to enl5 able the intermediate means to move all of the contact members in unison to open or close the circuit, each mechanical connection including an electro-responsive latch bodily movable with the corresponding contact member and automatical- 20 ly releasable upon the attainment of abnormal current conditions in the corresponding leg of the circuit to permit automatic circuit-opening movement of the corresponding contact member independently of the intermediate means and ln- 25 dependently of any other contact member, a releasable means operatively connecting the operating member with the intermediate means, and

. means adapted to be actuated by any one ofthe contact members upon independent circuit-open- 30 ing movement thereof and serving upon being so actuated to release the last said releasable means and permit the intermediate means and each remaining contact member to move to their opencircuit positions independently of the operating member.

13. In an automatic circuit breaker comprising a stationary support and a movable operating member, the combination with the said support and member of a plurality of separate circuit 40 breaker units, each comprising a movable intermediate member, a movable contact member. biased toward its open-circuit position, and a. mechanical connection normally operative to enable the intermediate member to move the contact member which mechanical connection includes an electro-responsively controlled device automatically releasable upon the attainment of abnormal current conditions in the circuit to permit circuit-opening movement of the contact member independently of the intermediate member, each of the saidunits being detachably mounted on the support and having its intermediate member detachably connected with the operating member so that each unit may be detached or attached independently of each other unit.

14. In an automatic circuit breaker comprising a stationary support, a movable operating member and a releasable operative connection movable by the operating member, the combination with the said support, member and connection of a plurality of separate circuit breaker units, each comprising a movable intermediate member, a movable contact member biased toward its opencircuit position, and a mechanical connection normally operative to enable the intermediate member to move the contact member which mechanical connection includes an electro-responsively controlled device automatically releasable upon the attainment` of abnormal current conditions in the circuit to permit circuitopening movement of the contact member independently of the intermediate member, each of support and having its intermediate member detachably connected with the operative connection so that each unit may be detached or at-v tached independently of each other,` unit, and means dependent upon the operation of the electro-responsively controlled device of any one of the units and serving to release the said operative connection and permit the intermediate members and each remaining contact member to move to their open-circuit positions.

15. In an automatic circuit breaker comprising a stationary support, a movable operating member and a releasable operative connection movable by the operating member, the combination with the said support, member and connection of a. plurality of separate circuit breaker units,

' each comprising a movable intermediate member,

a movable contact member biased toward its open-circuit position, and a mechanical connection normally operative to enable the intermediate member to move the contact member which mechanical connection includes an electro-responsively controlled device automatically releasable upon the attainment of abnormal current conditions in the circuit to permit circuit-opening movement of the contact member independently of the intermediate member, each of the said units being detachably mounted on the support and having its intermediate member detachably connected with the operative connection so that each unit may be detached or attached independently of each other unit, and means adapted to be actuated by any one of the contact members upon independent circuit-opening movement thereof and serving upon being so actuated to release the said operative connection and permit the intermediate members and each remaining contact member to move to theirI opencircuit positions.

JOSEPH SACHS.

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