USRE21010E - Automatic circuit breaker - Google Patents

Description

Feb. 21, 1939. J. SACHS AUTOMATIC CIRCUIT BREAKER origin-a1 'Filed July 28. 1922 :s sheets-sheet .1

arnsy FebQzl, 1939. J SACHS Re. 21,010

AUTOMATIC CIRCUIT BREAKER Original Filed July 28. 1922 5 Sheets-Sheet 2 hyenbar 'l 1:/'051550/7I 5551/25 Feb. 21, 1939. J. SACHS AUTOMATIC CIRCUIT BREAKE' Original Filed July 28. 1922 3 Sheets-Sheet 3 Reis/sued Feb. 21; 1939 UNITED STATES PATENT OFFICE AUTOMATIC CIRCUIT BREAKER Joseph Sachs, West Hartford, Conn., assigner to Colts Patent Fire Arms Manufacturing Company. Hartford, necticut Conn., a corporation of Con- Orlginal No. 1,736,372, dated November 19, 1929, Serial No. 303,544, September 1, 1928, which is a division of Serial No. 578,125, July 28, 1922. Application for reissue June 11, 1938, Serial No.

23 Claims.

l member or handle which 'is adapted to close the circuit after an automatic opening thereof, the said operating member or handle being so connected that it cannot serve to prevent the automatic opening. The said operating member or handle may if, desired be arranged to also open and close the circuit for normal switch purposes. In the drawings the circuit breaker is illustrated as forming a part of a meter service installation but it is well adapted for use otherwise.

One object of the present invention is to provide an improved circuit breaker of the type described wherein the excess current responsive means includes two more or less separate electro-responsive devices adapted to be connected in different portions of the circuit `and mechanically connected to control circuit opening and closing means comprising two pairs of sta.- tionary and movable contacts adapted to be connected respectively in' the same diierent portions of the circuit. As concerns this phase of the invention the two electro-responsive devices may be of the same type or of different types as found preferable, but there are important advantages inl electro-thermally.. responsive devices each oi' which acts only after a predetermined delay fol-nl lowing the attainment of excess current conditions in the corresponding portion of the circuit. The two separate electro-responsive devices when connected in different portions of the circuit, as for instance in the two separate legs thereof, provide protection against excess current conditions existing in one portion or leg 'of the circuit and not in another.

Another important object of the invention is to provide a circuit breaker of the type described wherein the excess current responsive means is operative by the thermal effect 'and by the electro-magnetic effect of the current and tends upon J the passage of excess current therethrough and VV'as the result of one or both of the said effects to cause the opening of the circuit. It is well known that an electro-magnetic device will act more quickly than an electro-thermal device and therefore by providing both an electro-magnetic electro-thermal device when a moderate overload condition exists.

Another object of the invention is to provide certain improved features and details of mechanical construction providing simplicity oi' construction and reliability of operation.

Other objects of the'irlvention will be apparent from the following speciiication and claims.

The application upon which was issued my original Patent No. 1,736,372 was a division of my then copending application for Electric service installation Serial No. 578,125 iiled July 28, 1922 issued on December 18, 1928 as Patent No. 1,696,150.

In the accompanying drawings I have shown three embodiments of the invention which have been .selected as illustrative thereof. It is to be understood, however, that the construction may invention as set forth in the claims forming a part of this specication.

Of the drawings:

Fig. 1 is a front view of a circuit breaker embodying the invention, this being shown in conjunction with an enclosing cabinet and an electric meter. A portion of the front cover of the cabinet is broken away and a portion of the circuit breaker mechanism is shown in section.

Fig. 2 is a side view of the parts shown in Fig. 1.

Fig. 3 is an enlarged transverse sectional view taken along the line 3--3 of Fig. 1.

Fig. 4 is an enlarged fragmentary sectional View taken along the line 4-4 of Fig. 3.

Fig. 5 is an enlarged sectional view taken along the line ,5--5 of Fig. 3.

Fig. 6 is an enlarged fragmentary perspective view showing a detail. e

Fig. 7 is an enlarged fragmentary iront view somewhat similar to Fig. 1 but showing an alternate embodiment of the invention.

Fig. 8 is a' transverse sectional view taken along the line 8 8 of Fig. 7.

Fig. 9 is a fragmentaryisectionfal view taken along the lines 9--9 of Figs. 7 and 8.v

Fig. 10 is a fragmentary front view similar to Fig. 7 but showing another alternate embodiment of the invention.

Fig. 11 is a transverse sectional view taken along the line II--ll of Fig. 10.

Referring to the `drawings it will be observed that the circuit breaker is shown as enclosed in a cabinet I having side walls 2, 2 and also having a cover 3 adapted to be sealed in closed position. The said cabinet l is provided with one wall, as

for instance. the upper end wall 4, having or adapted to have an opening therein for protective cooperation with the terminal chamber portion ofan electric meter such as M. The relationship between the circuit breaker, the enclosing cabinet, and the meter form no part of the present invention and need not be set forth in further detail, as these features are set forth in detail and claimed in my aforesaid Patent No. 1,696,150.

The cabinet I contains an insulating or insulated base 5, preferably though not necessarily made in one piece and secured therein. The base 5 carries the wire terminals 5, 6 connectible with the service wires and Wire terminals II, 9 connectible'with the load wires, it being understood that the number of such terminals depends on the number of wires or legs of the circuit for which the apparatus is adapted. In the embodiment of the invention as shown I also provide wire terminals 1, 1 and 8, 8 connectiblewith wires eX- tending to and from the meter. Movable switch connectors or contacts III, I0 are connected respectively between the pairs of terminals 8 and 9, the said connectors thus preferably being in the circuit after the meter. Fig. l shows the circuit diagram for a common two-wire circuit, the two incoming service wires being marked Il and the outgoing load or house wires being marked I2. The switch connectors or contacts I0 are movably mounted to bridge and connect the opposed spring clip contacts I3', I3, which are mounted on the base and connected respectively to the terminals 8 and 8. The contacts I 0, III` are movable in opposite directions into and out of engagement withl the respective stationary contacts I3, I3. Each connector or contact ID with its associated contacts I3, I3 or both of the connectors I0 with their respective contacts constitute circuit opening and closing means.

The said switch connectors III are ring-formed at their centers, as shown in Fig. 4, and both are molded into a hub Il of insulating material, this hub being mounted on or concentric with a shaft I5 and conned against endwise movement between two upstanding brackets I 6, I5 securedr to the base 5. The bore of the hub extends through the rings of the connectors and is square or angular in cross-section, and the shaft I5, or at least a portion of it marked I1, conforms to the section so that the hub and its two switch connectors must turn with the shaft but the shaft can slide endwise or axially in the hub. The 4shaft I5 may be assumed to be journalled in the brackets I6, I5

and to form the support for the hub and connectors, such arrangement bein preferred. al-

though itl will be apparent that these or their such torsional effort is such as to turn the shaft and the switch connectors III out of the closed position `to the open circuit position shown by the full lines in Fig. 4. 'Ihe contact I0 is thus biased for automatic movement out of engagement with each of the contacts I3 to open the circuit.

By its outward pressure, the spring I8 normally thrusts the roller cross head I8 on the shaft I5 against or toward the disc in whichV position the said cross `head rollers are situated between and bear upon the straight and axially 'directed edges of two'opposed lugs 2| bent up from the edges of the disc. as shown more clearly in Fig.l 6. the disc 2II will be recognized from the drawings as forming a part of the hub structure of the outside crank handle or operating member 22, being designed to serve as the means which retains the hub proper in the hole in the box wall which forms the journal seat for the handle. The crank or operating member 22 is movable in opposite directions between an open-circuit position and a closed-circuit position, the open-circuit position being shown by dot-and-dash lines in Fig. 2, and the closed-circuit position being shown by full lines. It will be observed that movement of the crank to its upper position actuates the rock-shaft through the engagement of lugs 2l with rollers I9 and rotates the switchconnectors I II in the direction to close the circuit and against the torsion of spring I8.

The cross head I9 in conjunction with the lugs 2Ih constitute a releasable latch which resiststhe circuit-opening bias of the movable contacts when Outside the box wall, the handle 22 is subject to the pressure of a spring 23 thrusting at an eccentric point 24 thereon and adapted to be carried past its dead center position as the handle is turned from its upper toits lower position (Fig. 2) This spring imparts a full throw to the handle in both directions and in the handle position corresponding to the closed position of the switch connectors, it exerts suillcient pressure on the handle to resist the torsion of the spring I8 so that although the latter constantly acts in the direction to open the switch, such action is prevented by the counter-force of the handle spring, more or less supplemented by the friction of the parts. When however the handle is turned, such resistance is removed and the spring I8 then acts to turn the shaft and thereby open the circuit. Thus the movement of the handle opens and closes the switch connectors and thereby the handle constitutes the means, accessible to the customer, whereby he may turn the supply current on and ofi', as required, that is to say, whereby the device serves for general service-switching purposes.` The spring 23 is an over-center spring which tends to hold the operating member either in its open-circuit position or in its closed-circuit position. The said spring 23"together with the spring I8 constitute a spring means which normally tends to hold the movable contacts in their closed-circuit positions when the operating mem-'- ber or handle is in its closed-circuit position and which tends to move the movable contacts to their open-circuit positions upon movement of the operating member from its closed-circuit position tolatch represented by the disclugs and roller crosshead, and that endwise withdrawal -of the shaft so that the rollers I9 are disengaged from the lugs will break the connection and thereby deprive the customer of any control over the switching connectors. Such disengagement is accomplished automatically by the passage of a predetermined or excessive current through the circuit and obviously leaves the shaft unrestrained against the torsion of the spring I8, which thereupon instantly rocks the shaft and opens the circuit. 'I'he particular means for thus uncoupling the switch connectors from the customers' control consists of a current-responsive means included in the circuit or influenced by the current therein and arranged to act on the coupling device and which may be variously designed according to the design of the latter. 'I'he before described releasable latch 2|, I9 or the before described releasable mechanical connection 2|, I9, I5 or their mechanical equivalents and the electro-responsive means cooperative therewith may be regarded as controlling means for the movable contact and they will be so referred to.

In the present case as shown in Figs. 1 to 3 such automatic-means is an electro-magnet comprising two similarly wound coaxially arranged coils 25 each included in one 1eg of the circuit, preferably ahead of the meter and between the pairs of terminals 6 and 'I respectively, and jointly creating a magnetic circuitY through the internal and external fixed core pieces 26 and 2G and the y movable armature 21, which latter is mounted on or secured to the end of the shaft I5. A collar 28 is supplied at the joint, which may be designed to serve as a stop to limit both the endwise and the rotary movement of the shaft. As shown, the collar 2B has shoulders 28 of which one is shown in Fig. 3, these shoulders engaging the end of the screw holding the adjacent bracket I6.

Inasmuch as the coils 25 are permanently included in the circuit and conduct current as long as the switch connectors IIl are closed across the contacts I3, I3 it will be apparent that the armature 21 exertsa normal pull on -the shaft in the direction to slide it endwise through its bearings and throughthe hub III. This pull is against the endwise thrust of the spring I9 and the latter is selected or adjusted so as to resist the armature pull for all normal and safe current values, yielding only on the passage of a current equal to or in excess of, some predetermined standard of safety. Instantly on such displacement of the shaft, theconnectcr means I snap to'their open position, the circuit is opened, and the magnetic pull having ceased, the shaft comes to rest with its rollers I9 resting on the sloped sides of the lugs 2l, as indicated by the dotted lines in Fig. 5.

The two connectors I 0, ID are `moved simultaneously, thus opening both legs of the circuit. It

will be understood that this opening of both legsv of the circuit will occur even though an excessive current is flowing in only one leg. The opening operation takes effect without movement of the customers or users service-switching handle 22. In order for the user to close the circuit after an automatic opening thereof, it is only necessary/to swing the service-switching handle 22 downwardly in the direction to cause the bevelle'd lugs 2| to ride under the rollers I 9 until the latter snap back into their initial position between the straight edges of the lugs whereupon the switch connectors are again placed under the'customers control and the switch connectors to their closed position and the return of the handle turns the circuit is thus restored. If the cause of the excessive current has not been remedied, it will be e quite impossible for the user to complete a closure of the circuit, because the energization of the magnet will continue to repeat the uncoupling action so long as an excessive current passes and the apparatus thus also serves as an indicator to the user of a defective circuit condition.

Figures 7 to l1 represent two of the various possible modiiications of the invention as respects the kind of current responsive means used toproduce the automatic action. As shown the rock shaft I 5, or whatever agency ishused for effecting the opening of the circuit, is arranged to be shifted at least in part by the thermal effect of the current. This is done by substituting a thermo-active device in place of the electro-magnet 25, or two thermo-active elements in place of the two coils of the magnet, each element being connected in,

or associated with, one of the legs of the circuit,-

illustrated each thermal element 29 is constituted of a twin spiral strip of the same kind of bi-metallic material that is commonly used for thermostats. The centers of the two spirals are iixedly mounted on theinsulating base block 5 by suitable lugs 3U and 3| which also serve as the wire-connecting means or terminals Ii*l and la,

and the opposite'ends of the two spirals are con'-l nected together by a yoke 32`which straddles the extendedend I5a of shaft I5, being insulated therefrom by a plate 33 which is adapted to engage cross-pins 34 thereon. By this mounting the current path is from the terminal 6a through the adjacent spiral 29,across, the yoke 32 to the other spiral 29 and through the latter to the opposite terminal 1a. The heating effect of an excessive current expands the spirals inthe direction to uncurl them and thereby causes the yoke V32 to bear, through the insulating plate 33 on the cross-pins 34 in the direction to shift the shaft I5 endwise and open the coupler'with the same effect as the electromagnet` above described, the shaft however remaining free for rotative movement under the control of the handle. wThe electro-thermally responsive element 29, while pro# ducing the same mechanical result as the magnet,

is necessarily delayed in its action by reason of' the time needed to bring the element to the required effective temperature'.

Figs. 7 and 8 show one thermal element substtuted for one coil of the magnet whereas Figs. 10 and 11 show two thermal elements substituted rpectively for the two coils of the magnet. As shown in Figs. 7 and 8 the magnet and the thermal element cooperate with each other to release the movable contact,'the magnet being adapted to act more quickly in the case of ashort circuit and the thermal element providing a slightly delayed actipn in the'case of a moderate overload. As shown' in Fgs. 10 and 11 with one thermal element in each circ/uit leg magnetic action is entirelyy eliminated ample-.power being available from the thermal elements alone to produce reliable'action.

Meter test contact 35, 35 and 36, 36 may beprovided as shown for iacilitating-thetesting of thel meter, but the features of the construction as shown adapting it for use in meter testing are not claimed as a part of the present invention.

What I claim is:

1. An automatic circuit breaker comprising in combination, two circuit opening and closing means connectible respectively in different portions of the circuit and each comprising stationary and movable contacts, the said movable contacts being connected for movement in unison in opposite directions into and out of engagement ywith the stationary'contacts to open and close both portions of the circuit, spring means normally biasing the movable contacts for automatic movement to open-circuit positions, an operating member manually movable in opposite directions between open-circuit and closed-circuit positions, a releasable latch which resists the circuit-opening bias of the movable contacts when the said contacts and the operating member are in closed circuit positions but which upon release permits automatic circuit-opening movement of the movable contacts independently of the operating member, a wholly mechanical connection which is operable only while the latch remains engaged and which enables the operating member upon movement to its open-circuit or its closed-circuit position to eilect corresponding movement of the movable contacts to open or close both portions of the circuit forxnormal switching purposes, two automatic excess current responsive devices connectiblerespectively in the aforesaid different portions of the circuit, and means entirely mechanically dependent upon the excess` current responsive action 'cf either or both of the .last said 4devices for releasing the latch to permit the aforesaid automatic independent movement ot the movable contacts to open both portions of the circuit, the lastr said means enabling the latch to be automatically re-engaged upon movement of the operating member to open-circuit position so that the operating member may move the movable contacts from open-circuit positions to closed-circuit positions after automatic opening.

2. An automatic circuit breaker comprising in combination, two circuit opening and closing means connectible respectively in different portions of the .circuit and each comprisingstationary and movable contacts, the said movable contacts being connected for movement` in unison in opposite directions into and out of engagement with ythe stationary contacts to open and close both portions of the Icircuit, spring l means normally biasing the movable contacts for automatic movement to open-circuit positions, an operating member manually movable in opposite directions between open-circuit and closed-circuit positions, a wholly mechanical operating means normally enablingthe operating member upon movement to its open-cicuit or its closedcircuit position to eect corresponding 4movement of the movable contacts to open or close both portions of the circuit Ifor nornial switching purposes, the said operating means including a releasable latch which remains engaged during normal switching movements and which normalvly resists the circuit-opening bias of the movable contacts when the said contacts and the operating member 'are in closed-circuit positions but which upon release n' permits-automatic )circuitopening movement of the movable contacts independently of the ,operating member, two automatic excess current responsive devices connectible respectively in the aforesaid different portions Y dependent upon the excess current responsive acportions of the circuit, the last said means encally re-engaged upon movement of the operating member to open-circuitposition so that the operof the circuit, and means entirely mechanically tion of either or both of the last said devices for releasing the latch to permit the aforesaid automatic independent movement of the movable con-4 tacts to open both portions of the circuit, the last said means enabling the latch to be automatically re-engaged upon movement of the operating member to open-circuit position so that the operating lmember may move the movable contacts from bpen-circuit positions to closedcircuit positions after automaticopening.

`3. An automatic circuit breaker comprising in combination, two' circuit opening and closing means connectible respectively in different portions of the circuit and each comprising stationary and movable contacts, the said movable contacts beingconnected for movement in unison in oppositefdirections into and out of engagementwith the stationary contacts to operiv and close both portions of the circuit, spring means normally biasing the movable contacts for automatic movement to' open-circuit positions, an operating member manually movable in opposite 'directions between open-circuit and closedcircuit positions, a wholly mechanical operating means normally enablingr the` operating member upon movement to its open-circuit or its closedcircuit position to effect corresponding movement of the movable contacts to open or close both portions of the circuit for normal switching purposes, the said operating means including a releasable latch which moves bodily with the movable contacts and remains engaged duringI normal switching movements and which normally resists the circuit-opening bias of the movable contacts when the said contacts and the operating member are in closed-circuit positions but which upon release permits automatic circuitopening movement of the movable contacts independently of the operating member, two automatic excess current responsive devices connectible respectively in the aforesaid different portions of the circuit, and means entirely mechanically dependent upon the excess current responsive action of either or both of the last said devices for releasing the bodily movable latch to permit the aforesaid automatic independent movement of the movable contacts toppen both abling the bodilymovable latch to be automatiating membermay move the movable contacts from open-circuit positions to closed-circuit positions after automatic opening.

4. An automatic circuit breaker comprising in combination,v two circuit, opening andw closing means connectible respectively in diierent portions of the circuit and each comprising stationary andmovable contacts,.the said movable contacts being connected for movement in unisoniin opposite directions into and out 'of en-.

gagementwithxthe stationary contacts to open and close both portions of the circuit, springL means normally biasing the movable contacts for automatic movement to open-circuit positions,

an operating member manually movable in opy posite directions between open-circuit and closedcircuit positions, a releasable latch which resists the circuit-opening bias of the movable contacts when the said contacts and the operating member are in closed-circuit positions but which upon y release permits automatic circuit-opening movement of the movable contacts independently of lowing the attainment of excess current condi" tions in the corresponding portion of the circuit, and means entirely mechanically dependent upon the automatic action of either or both of the said electro-thermally responsive devices for releasing the latch to permit the aforesaid automatic independent movement of the movable contacts to open both portions of the circuit, the last said means enabling Ithe latch to be automatically re-engaged upon movement of the operating member to open-circuit position so that the operating member may move the movable contacts from open-circuit positions to closedcircuit positions after automatic opening.-

5. An automatic circuit breaker comprising in combination, two circuit ropening and closing means connectible respectively in different portions of the circuit and each comprising stationary and movable contacts, the said movable contacts being connected for movement in unison in opposite directions into and out of engagement with the stationary contacts to open and close both portions of the circuit, spring means normally biasing the movable contacts for automatic movement to open-circuit positions, an operating member manually movable in opposite directions between open-circuit and closed-circuit positions, a wholly mechanical operating means normally enabling the operating member upon movement to its open-circuit or its closedcircuit position to eiect corresponding movement of the movable contacts to open or close both portions of the circuit for normal switching purposes, the said operating means including a releasable latch which remains engaged during normal switching movements and which normally resists the circuit-opening bias of the movable contacts when the said contacts and the operating member are in closed-circuit positions but which upon release permits automatic circuitopening movement of the movable contacts independently of the .operating member, two devices connectible respectively in the aforesaid diierent portions of thecircuit and each including an electro-thermally responsive bi-metallic element adapted to be deflected automatically by heat after a predetermined delay following the attainment of excess current conditions in the corresponding portion of the circuit, and means yentirely mechanically dependent upon the excess current responsive deflection of either or both of the said bi-metallic elements for releasing the latch to permit the aforesaid automatic independent movement of the movable contacts to open both portions of the circuit, the last said means enabling the latch to be automatically reengaged upon movement of the operating member to open-circuit position so that the operating member may move the movable contacts from open-circuit positions to closed-circuit positions after automatic opening.

6. An automatic circuit breaker comprising in combination, two"circuit opening and closing means normally enabling the operating member/ upon movement toits open-circuit or its closedcircuit position to effect corresponding movement of the bridging connectors to open or close both portions of the circuit for normal switching purpos-es, the said operating means including a releasable latch which remains engaged during normal switching movements and which normally resists the circuit-opening bias of the bridging connectors when the said connectors and the operating member are in closed-circuit positions but which upon release permits automatic circuitopening movement ofthe connectors independently of the operating member, two devices connectible respectively in the aforesaid diierent portions of the circuit and each including an electro-thermally responsive element adapted to act automatically and after a predetermined delay following 'the attainment of excess current conditions in the corresponding portion of the circuit, and means entirely mechanically dependent upon the automatic action of either or both of the said electro-thermally responsive devices for releasing the latch to permit the aforesaid automatic independent movement of the bridging connectors to open both portions of the circuit, the last said means enabling the latch to be automatically re-engaged upon movement of the operating member to open-circuit position so that the operating member may move the bridging connectors from open-circuitpositions to closedcircuit positions after automatic opening.

7. An automatic circuit breaker comprising in combination, two circuit opening and closing means connectible respectively in different portions of the circuit and each comprising stationary and movable contacts, the said movable contacts being connected for movement in unison in opposite directions into andout of engagement I with the stationary contacts to open and close both portions of the circuit and the said contacts being normally biased for automatic movement to open-circuit positions, handle mechanism comprising a handle manually movable in opposite directions between open-circuit and closed-circuit positions and also comprising an `over-center spring tending to hold the handle mechanism, a wholly mechanical connection mal switching'purposes, two automatic excess current responsive devices connectible respectively in theI aforesaid different portions of the circuit, and \means dependent upon the excess current responsive action of either or both 'of the last said devices for releasing the latch to permit the aforesaid automatic independent movement of the movable contacts to open both portions of the circuit, the last said means enabling the latch to be automatically re-engaged upon movement of the handle to open-circuit position so that the handle mechanism may move the movable contacts from open-circuit positions to closed-circuit positions after automatic opening.

8'. An automatic circuit breaker comprising in combination, two circuit opening and closing means connectible respectively in 'diilerent portions of the circuit and each comprising stationary and movable contacts, the said movable'contacts being connected for movement in unison in opposite directions into and out of engage- 'ment with the stationary contacts to open ,and

close both portions of the circuit and the said contacts being normally biased for automatic movement to open-circuit positions, handle-mechanism comprising a handle manually movable in opposite directions between open-circuit and closed-circuit positions and also comprising an over-center spring tending to hold the handle either in its open-circuit position or in its closed-circuit position,` a wholly mechanical means normally enabling the handle upon movement of the handle to its open-circuit or its closed-circuit position to effect corresponding movement of the movable contacts to open or close both portions of the circuit for normal switching purposes, the last said means including a bodily movable'relasable latch which remains engaged during normal switching movements and which normally resists the circuit-opening bias of the movable contacts when the said contacts and the handle are in closed-circuit positions but which upon release permits automatic circuit-opening movement of.

the movable contacts independently of the handle mechanism, two automatic excess current responsive devices connectible respectively in the aforesaid different portions of the circuit, and means dependent upon the excess current responsive action of either or both of the last said devices for releasing the bodily movable latch to permit the aforesaid automatic independent movement ofthe movable contacts to open` both portions of the circuit, the last said means enabling the latch to be automatically re-engaged upon movement of the handle to open-circuit position so that the handle mechanism may move the movable contacts from open-circuit positions to closed-circuit positions after automatic opening.

9. An automatic circuitvbreaker comprising in,

combination, two circuit opening and closing means connectible respectively indifferent portions of the circuit and each comprising stationary and movable contacts, the said movable contacts being connected for movement in unison in opposite directions into and out of engagement with the stationary contacts to open and close both portions of thel circuit, spring means normally biasing the movable contacts for automatic movement to open-circuit positions, handle mechanism comprising a handle manually movable in opposite directions between open-circuit and closed-circuit positions and also comprising an over-center spring separate from the said biasing spring means and tending to hold the hanor its closed-circuit position to eiectqcorrespond-4 ing movement of the-movable ,contacts to open or close both portions of the circuit fornormal switching purposes, the last said means including a. bodily movable' releasable latch which remains engaged during normal switching movements and: which normally resists the circuit-opening bias of the movable contacts when the said contacts and the handle are in closed-circuit positions but which upon release permits, automatic circuit-opening movement ofthe movable contacts independently of the handle mechanism, two automatic excess current responsivedevices connectible respectively in the aforesaid dierent portions of the circuit, and means dependent upon the excess current responsive action of either or both of the last'said devices for releasing the bodily movable latch to permit the aforesaid automatic independent movement of the movable contacts to open both portions oi' the circuit, the last said means enabling the latch to ltions of the circuit and each comprising stationary and movable contacts, the said movable contacts being connected for movement in` unison in opposite directions into and out of engagement with the stationary contacts to open and a wholly mechanicalclose both portions of the circuit and the said cons tacts being normally biased for automatic movement to open-circuit positions, handle mechanism comprising a handle manually movable in opposite directions between open-circuit and closed-circuit positions and also comprising an over-center spring tending'to hold the handle either in its open-circuit position or in its closedcircuit position, a releasable latch which resists the circuit-openingibias of the movable contacts when the said cnta'cts and the handle are in closed-circuit positions but which upon release permits automatic circuit-opening movement of the movable contacts independently of the handle mechanism, a wholly mechanical connection which is operable only while the latch remains engaged and which enables the handle mechanism upon movement of the handle to its opencircuit or its closed-circuit position to eiect corresponding movement of the movable contacts to open or close both portions of the circuit for normal switching purposes, two devices connectible respectively in the aforesaid dlierent portions of the circuit and each including an electro-thermally responsive bi-metallic element adapted to be deflected automatically by heat after a` predetermined delay following the attainment of excess current conditions in the corresponding portion of the circuit, and means entirely mechanically dependent upon the excess current responsive deection of either or both of the said bi-metallic elements for releasing the latch to permit the aforesaid automatic independent movement of the movable contacts to open both portions of the circuit, the last said .means enabling the latch to be automatically open-circuit position so that the handle mechanism may move the movable contacts from open-circuit positions to closed-circuit positions after automatic opening.

11. An automatic circuit breaker comprising in combination, two circuit opening and closing means connectible respectively in different portions of the circuit and each comprising stationary and movable contacts, the said movable contacts being connected for movement in unison/in opposite directions into and out of engagement with the stationary contacts to open and close both portions of the circuit and the said contacts being normally biased for automatic movement to open-circuit positions, handle mechanism comprising a handle manually movable `in opposite directions between open-circuit and closed-circuit positions and also comprising an over-center spring tending to hold the handle either in its open-circuit position or in its closed-circuit position, a wholly mechanical means normally enabling the handle upon .movement of the handle to its open-circuit or its closed-circuit position to eifect corresponding movement of the movable contacts to open or close both portions of the circuit for normal switching purposes, the last said means including a bodily movable releasable latch which remains engaged during normal switching movements and (which normally resists the circuit-opening bias of the movable contacts when the said contacts andthe Ihandle are in clcsedcircuit positions but which upon release permits automatic circuit-opening movement of the movable contacts independently of the handle mecha-- nism, two devices connectible respectively in the aforesaid different portions of the circuit and each including an electro-thermally responsive element adapted to act automatically and after ,a predeterminedI delay following the attainment of excess current conditions in the corresponding portion of the circuit, and means entirely mechanically dependent upon the automatic action of either or both of the said electro-thermally responsive devices for releasing the bodily movable latch to permit the aforesaid automatic independent movement of the movable contacts (to open both portions of the circuit, the. last said means enabling the latch to be automatically reengaged upon movement of the handle to opencircuit position so that the handle mechanism may move the movable contacts from open-circuit positions to closed-circuit positions after automatic opening.

12. An automatic circuit breaker comprising in combination, two circuit opening and closing means connectible respectively in diierent portions ofthe circuit and each comprising two s ationary contacts and two movable contacts constituting a bridging connector which is electrically free when disengaged from the stationary contacts, the said bridging connectors being connected for movement in unison in opposite directions into and out of engagement withthe stationary contacts to open and close both portions of the circuit and being normally biased for automatic movement to opencircuit positions, handle mechanism comprising a handle manually movable in opposite directions between'fopen-circuit and closed-circuit positions and also comprising an over-center spring tending to hold the handle either in its open-circuit position or in its closed-circuit position, a releasable latch which resists the circuit-opening bias of ,the bridging.

connectors when the said connectors and the handle are in closed-circuit positions but which upon release permits automatic circuit-opening movement of the bridging connectors independently of the handle mechanism, a wholly mechanical connection which is operable only while the latch remains engaged and which enables the handle mechanism upon movement of the handle to its open-circuit or its closed-circuit position to effect corresponding movement of the bridging connectors to open or close both portions of the circuit for normal switching purposes, two automatic excess current responsive devices connectible respectively in the aforesaid different portions of the circuit, and means dependentl upon the excess current responsive action of either or both of the last said devices for releasing the latch'to permit,` the aforesaid automatic indemeans enabling the latch to be automatically reengaged upon movement ofthe handle to opencircuit position so that the handle mechanism may move 'the bridging connectors from opencircuit positions to closed-circuit positions after automatic opening.

13. An automatic circuit breaker comprising in combination, a circuit opening and closing means, a manually movable operating member, excess current responsive means operative by electrothermal andelectro-magnetic effect, means operatively dependent upon the said current responsive means for automatically operating thel said opening and closing means independently of the operating memberto open the circuit, and means enabling the operating member to effect the operation of. the opening and closing means to close the circuit after automatic opening thereof as aforesaid, the last said means being inoperative to prevent the said automatic excess current responsive opening of the circuit.

14. An automatic circuit breaker comprising in combination, two electric contacts normallydn engagement with each other and one of them biased for automatic movement out of such engagement to open the circuit, a controlling means for the movable contact normally operative to prevent the said automatic movement thereof and including two 'excess' current responsive devices one electro-thermal and the other electromagnetic and each tending upon the passage of excess current therethrough to effect the release of the said movable contact and thereby permit the said automatic circuit opening movement thereof, a manually movable operating member,

andl means interposed between the operating for the movable contact including a releasab'le' latch normally operative to prevent the said automatic movement thereof and also including two excess current responsive devices one electro-thermal and the otherelectro-magnetic and each tending upon the passage of excess current therethrough to release the latch and thereby pendent movement of the bridging connectors to,r open b oth portions of the circuit, the last sai/dy permit the automatic circuit opening movement of the movable contact, a manually movable operating member, and means interposed between 16. An 'automatic/ circuit breaker comprising in combination, two electric contacts normally in engagement with each other and one of them biased for automatic movement out of such engagament to open the circuit, a releasable mechanical 'connection normally operative to prevent the said automatic movement of the movable contact, releasing means additional to the mechanical connection and including electrothermal and electro-magnetic devices connectible in series with each other and with` the contacts and each tending upon the passage of excess current therethrough to eiect the release 'of the said mechanical connection and thereby permit the said automatic circuit opening novement of the movable contact, a manually movable operating member, and means interposed between the operating member and the movable contact enabling the former to return the latter to normal position after an `automatic circuit opening movement, the last saidy means being inoperative to prevent the said automatic circuit opening movement when the mechanical connection is released as aforesaid by the releasing means.

1'1. An automatic circuit breaker comprising in combination, two electric contacts normally in engagement with each other and one of )them biased for automatic movement out of ,such engagement to open the circuit, a controlling means for the movable contact normally operative toprevent the said automatic movement thereof and including two excess current responsive devices one electro-thermal and the other electro-magnetic and each tending upon the passage of excess current therethrough to effect the release of the said movable contact and thereby permit the said V automatic circuit opening movementV thereof, separate terminals for the said excess current responsive devices whereby they may be connected in diierent portions lof the circuit, a manually movable operating member, and means interposed between the operating member and the movable contact enabling the former to return the latter intouengagement with the other contact after an automatic circuit opening movement, the last said means being inoperative to prevent-the said automatic excess current responsive circuit opening movement.

18. An automatic circuit breaker comprisingin combination, a circuit opening and closing means, a manually movable operating member...

excess current responsive means operative by electro-thermal.. and electro-magnetic effect, means operatively dependent upon the said current responsive means for automatically operating the said opening and closing means independentlyof the operating member to open the circuit, and means enabling the operating member to effect the operation of the opening and closing mj'eans to close the circuit after automatic opening thereof as aforesaid and to eiect the operation thereof to both open and close the circuit for normal switching purposes, the last said means being inoperative to prevent the/said' automatic excess current^ responsive opening of the circuit. 1 v,

19. An' automatic circuit breaker comprising in tcombination, two electric contacts normally in engagement with each other and one of them biased for automatic movement `out of such engagement to open the circuit, a manually movable operating member, and controlling means for the movable contact including a releasable mechanical connection between the operating member and the movable contact normally o'perative to prevent the said automatic movement of the latter and enabling the operating member to eiect the movement of the movable contact in i either direction for the normal openingand closing of the circuit, the said controlling means also including two excess current responsive devices one electro-thermal and the other electro-magnetic and each tending upon the passage of excess current therethrough to act upon the said mechanicalazonnectionl so as to thereby release the said movable contact and permit the said automatic circuit opening movement thereof independently of the operating member.

20. An automatic circuit breaker comprising in combination, two electric contacts normally in engagement with each other and one of them biased for automatic niovement out-of such engagement to open the circuit, a manually movable operating member, a releasable mechanical connection between the operating member and the movable contact normally operative to prevent the said automatic movementv of the latter and enabling the operating member to eifect the movement o f the movable contact in either direction for the normal opening and closing of the circuit, and releasing means additional to the said mechanical connection .and 'including two excess current responsive devices one electrothermal and the other electro-magnetic and each tending upon the passage of excess current thereoperatively dependent upon the electro-thermal effect or the electro-magnetic eifect or both of the last said means for. automatically operating both of the saidopening and closing means independently of the operatingrmember to open the circuit at two placesand means enabling the operating member to effect the operation of both of the opening and'closng means to close the circuit after automatic opening thereof as aforesaid and to effect the operation thereof to both open and close the circuit at two places for normal switching purposes, the last said means being inoperativeto prevent the said automatic excess current responsive opening of the circuit.

22. An automatic circuit breakercomprising in combination, a shaft movable rotatively and axially,- a contact member mounted on the shaft for rotation therewith but held against axial movement therewith, a fixed contact with which the cont/act portion of the movable contact member normally engages, a manually movable operating `member, a mechanical connection between the 21,010 ment of the shaft, means automatically operativev upon the release of the mechanical connection as aforesaid for rotating the shaft and the contact member independently of the operatingmember to disengage the contact member from the Iixed contact, and an electro-responsive device connectible in series with the said contacts and serving upon the passage of excess-current therethrough to move the shaft axially to effect the said release of the said mechanical connec tion.

23. An automatic circuit breaker comprising in combination, a shaft movable rotatively and axially, a contact member mounted on the shaft for rotation therewith but held against axial movement therewith, a flxedcontact with which the contact portion ofthe movable contact member normally engages, a manually movable operating member, a mechanical connection between the operating member and the shaft at one side of the said contacts and normally enabling the operating member to move the' shaft and thereby move the contact member into or out of engagement with the xed contact, the said connection' being releasable by axial movement of the shaft, means automatically operative upon the release of the mechanical connection as aforesaid for rotating the shaft and the contact member independently of the operating member to disengage the contact member from the fixed contact, and an electro-responsive device connectible in series with the 'said contacts and connected with the shaft at the opposite side of the said contacts and serving upon the passage of excess current therethrough /to move the shaft axially to effect the said release of the said mechanical connection. l

' J OSEPH SACHS.

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