US2349631A

US2349631A - Circuit breaker

Info

Publication number: US2349631A
Application number: US465242A
Authority: US
Inventors: Lindstrom Ture; Paul O Langguth
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1942-11-11
Filing date: 1942-11-11
Publication date: 1944-05-23
Anticipated expiration: 1961-05-23

Description

-May 23g E944@ T. LNBs-mom ET AL.

CIRCUIT BREAKER Filed. Nov. ll, 1942 4 Sheets-Sheet 2 WITNESSES; 4

INVENTORS ./900/ an ATTOR Y May 239 W4@ T. MNDSTRQM TAL CIRCUIT BREAKER Filed Nov. ll, 1942 SnGeZS-Shee E mmm@ 239 i944 T. UNDSTRGM ET AL. 293499633.

CIRCUIT BREKER Filed Nov. ll, 1942 4 Shee'ts-Sheec 4 ATOR'NY ParentedMay 23, 1944 CIRCUIT BREAKER Ture Lindstrom, Edgewood, and Paul 0. Langguth, Wilkinsburg, Pa., assignors to Westinghouse Electric V8; Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 11, 1942, Serial No. 465,242 16 Claims. (Cl. 200-89) This invention relates to circuit breakers and more particularly to circuit breakers of the type which are closed manually and opened by tripping the breaker either manually or automatically in response to predetermined abnormalconditions such as overloads.

An object of the invention is the provision of an improved circuit breaker in which the contacts are trip free of the closinglever in. the closed position of the lever and the breaker is of shockproof construction so that it will not be falsely tripped or opened by jars or shocks.

Another object of the invention is the provision of an improved shockproof circuit breaker which is trip free of the operating lever during closing movement of the lever 'and in the closed position of the lever, and in which the breaker can be locked in closed position to prevent opening thereof in response to overloads by locking the operating lever in a predetermined position other than the closed position.

Another object of the invention is'the provision of an improved circuit breaker having an operating spring which provides the tripping force for opening the breaker, supplies the Contact pressure in the closed position and also holds the breaker' latch in released position until the mechanism is reset to permit resetting of the mechanism.

Another object of the invention is the provision of an improved circuit breaker embodying a toggle linkage for holding the breaker in closed position and an operatingspring connected at one end to a lever having limited movement; and at its other end to the contact means whereby the spring acts through the lever to initiate collapse of the toggle upon release of the breaker latch and then provides the opening force for completing the opening movement of the breaker.

Another object of the invention is to provide an improved circuit breaker wherein one end of the operating spring acts with a comparatively large moment arm on one end of an operating toggle to start the toggle overcenter in a direction to cause opening of the contacts, the spring acting on the other end of the toggle to complete the opening movement of the toggle.

Another object of the invention is to provide an improved circuit breaker in which the operating spring applies a force at a plurality of points of an operating toggle to start the toggle overcenter in a direction to cause opening of the contacts and applies a force at a single point of the toggle to complete the opening movement.

Another object-l of the invention is to provide an improved circuit breaker in which one end of the operating spring is attached to a member which cooperates with this operating mechanism to start the opening movement of the breaker and the other end of the spring is attachedto the contact structure to complete the opening movement.

Another object of the invention is the provision of a circuit breaker having an improved operating mechanism wherein an operating spring operates an actuating member to move the operating mechanism a predetermined distance in opening direction, and applies a force to the contact structure to complete the opening movement, the spring also acting, when the breaker is closed, to provide contact pressure.

Another object of the invention is the provision of an improved circuit breaker of rugged construction which is simple, reliable in operation and inexpensive to manufacture.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of a single embodiment thereof when read in conjunction with the accompanying drawings, in which:

Figure 1 is a front elevational view of a threepole circuit breaker embodying the principles of the invention, with the cover removed and the operating member broken away.

Fig. 2 is a vertical sectional view taken substantially on line lI-II of Fig. 1 and showing the circuit breaker operating mechanism in the closed position.

Fig. 3 is a vertical sectional view similar to Fig. 2, but showing the mechanism in the tripped open position and before the trip mechanism has been reset.

Fig. 4 is a vertical sectional view similar to Fig. 2, but showing the mechanism reset and before the contacts are closed.

Fig. 5 is a fragmentary sectional view taken on line V-V of Fig. 2. and showing the pressure connection between the Contact levers and the contact arms.

Referring to the drawings, the circuit breaker includes a base Il of molded insulating material upon which the several elements of the breaker mechanism are mounted, and a cover I3 also of molded insulating material. The circuit breaker itself comprises three separate poles, each of which is provided with upper and lower terminals I5 and I1 for connecting said poles in electrical circuits, a stationary contact I9, a pair of movable 'contacts 2|, an arc extinguishing device 23, and a trip device indicated generally at 25. A common operating mechanism, indicated. generally at 21, is provided for simultaneously operating the contacts for all of the poles of the breaker.

The stationary contact I9 for each pole is mounted on a conductor 29 secured to the base by means of a bolt 3| and a nut 33 threadedly engaging the terminal l5. The movable contacts 2| are mounted on contact levers 35, there being two contact levers 35 (Fig. 1) and two contacts 2| provided for each pole of the breaker. The contact levers are pivotallymounted on a pivot pin 31 supported in a contact arm comprising a pair of spaced parallel arms 39. The contact arms 39 are mounted on a pivot pin 4| supported in an ear 43 formed outwardly from the upper end of a conductor 45, secured to the base bymeans of a bolt 41. The conductor 45 is electrically connected to one end of a trip coil 49 of the trip device 25, and the other end of the trip coil is connected to the lower terminal |1 by means of a conductor I. The electrical circuits for the three poles are essentially the same, therefore only the circuit for the center pole will be traced. 'Ihis circuit extends from the terminal I5 through the conductors 29, the stationary and movable contacts |92|, the contact levers 35, through a pressure connection to the contact arms 39, the ear 43 of the conductor 45, conductor 45, trip coil 49 and the conductor 5| to the terminal I1.

Referring to Fig. 5, the pressure contact forming the electrical connection between the contact levers 35 and the contact arms 39 comprises a sleeve 42 rotatably supported on the pivot pin 31. The contact levers 35 are mounted on the sleeve 42 and are spaced apart by a spacer 44. The sleeve 42 also projects through openings in the contact arms 39 which are brought into pressure contact with the contact levers 35 by means of spring Washers 46 which are tensioned against the sides of the contact arms 39 by means of nuts 48 threadedly engaging the threaded ends of the sleeve 42. A similar connecting means (not shown) is provided for forming an improved electrical contact between the contact arms 39 and the ear 43 (Fig, 2) of the conductor 45. This structure eliminates .the use of the usual exible shunt conductors.

The operating mechanism 21 is'mounted in a main frame comprising spaced parallel frame members 55 (Figs. 1 and 2) rigidly connected by

cross bars

51 and 59 and by a rod 60 upon which is mounted a spacer 82. The main frame is secured to the central portion of the base I.e by means of bolts 6I (only one being shown) extending through the base and threadedly engaging the cross bar 51. Mounting feet 63 (Fig. 1) are also provided on the frame members 55 and are secured to the base by means of bolts 65.

The operating mechanism includes a main operating toggle comprising toggle links 61 and 69 (Fig. 2) pivotally connected by a knee pivot pin 1 I. The toggle link 61 comprises a pair of spaced parallel links, rigidly connected by means of a cross bar 13. The pivot pin 31 for the contact levers 35 extends beyond the sleeve 42 (Fig. 5) and the ends of the pin engage openings in the left-hand end (Fig. 2) of the toggle links 61 to pivotally connect the movable contact structure to the operating toggle. The outer end of the toggle link 69 is pivotally connected by means of a pivot pin to a bell crank lever 11 comprising a pair of spaced parallel levers pivotally mounted on a pivot pin 19 supported in the main frame. The levers 11 are disposed on opposite sides of the toggle link 89 and at their free ends carry a latch roller 8| rotatably mounted on a pivot pin 83 supported in the levers 11. The latch roller 8| is adapted to cooperate with a latch lever 85, which forms a part of the trip device 25, to restrain the operating mechanism in closed position (Fig. 2) against the tension of operating springs 81, there being two springs 81 provided for the center pole (Fig. 1) and one for each ofthe outer poles. The inner ends of the springs 81 for the center pole (Fig. 2) are hooked over a pin 89 secured in the lower ends of the contact levers 35 and the pin 89 projects through slots 9| in the contact arms 39. The outer ends of the springs 81 for the center pole are hooked over the ends of a pin 93 which is mounted in and projects from each side of a lever 95. The lever 95 is pivotally supported on a pivot pin 91 mounted in the main frame 55 and is biased against a roller 99 rotatably mounted on a pin |0| carried by the lever 11.

Also forming a part of the operating mechanism is a manually operable U-shaped lever |03 (Fig. 2), the two legs of which are pivoted intermediate their ends on pivot pins |05 extending inwardly from the frame members 55 (see Fig. 1). The transverse portion of the operating lever |03 is molded integral with an arcuate shield |01 (Fig. 2) of molded insulating material. Amanual operating handle |09 projects outwardly from the shield |01 through an opening in the cover |3, the shield |01 serving as a projecting closure for the opening. The inner endsl of the legs of the operating lever |03 carry a rod I i3 upon which is rotatably mounted a roller I I5 adapted to be operatedby manual operation of the handle |09 and the lever |03 in one direction to reset the trip device Iand in the Opposite direction close the contacts following an opening operation of the breaker. The lever |03, together with the handle |09 and the roller ||5, is biased by means of springs ||1 in a clockwise direction to the position shown in Fig. 2, wherein the roller ||5 rests against the under side of the toggle link 69. Each of the springs ||1 has one end hooked into a hole in one leg of the lever |03 and the other end is hooked over a rod I9 supported in and extending between the members of the main frame 55.

The movable contact structures for the two outer poles of the breaker are substantially the same as the previously described structure for the center pole. Each of the outer poles includes a pairvof contact levers 35 pivotally connected to a pair of contact arms 39 by means of a, pivot pin 31, and electrically connected to the contact arms 39 by means of a pressure contact arrangement such as is illustrated in Fig. 5. Also thecontact arms 39 for the two outer poles are similarly mechanically and electrically connected to the ear of a conductor 45. Each of the operating springs 81 for the outer poles has its inner end hooked over a pin 89 (Fig. l) which is supported in and extends between the lower ends of the contact levers 35. The outer ends of the springs 81 for the outer poles are anchored to bars |23 of insulating material secured by means of angle brackets |25 to the frame members 55.

The movable contact structures for the outer poles are each connected by means of a pair of links |21 (Fig. 1), which engage the ends oi the pivot pins 31, to a tie bar |29 of insulating material. The links |21 are securedto the tie'bar |29 by means of bolts |3|, and the tie bar is secured to the toggle links 61 by means of bolts |33. In this manner the movable contact structures for all three poles of thebreaker are connected together so that they operate as a unit.

It was previously stated that the operating mechanism including the movable contact structure, is restrained in closed position (Fig. 2) by means of the latch roller 9| on the free end of the bell crank 11 engaging the latch lever 35. The latch lever 95 is pivoted on a pivot pin |35 supported in the frame members 55 and is provided with a shoulder |31 to receive a'nd restrain the latch roller 8|. The latch lever 85 is normally restrained in latching position by a tripping toggle comprising toggle links |39 and |4|. The toggle links |39 and |4| are pivotally connected by a knee pivot pin |43 and the toggle link |39 is pivotally connected to one arm of the latch lever 65 by means of a pivot pin |45. The lower end of the toggle link |4| is formed over at right angles and is rigidly secured by means of a bolt |41, to a trip bar |49 of insulating material pivotally supported in the main frame 55. The bolt |41 also serves to secure a counterbalance to the trip bar |49 opposite to the tripping toggle |39-|4|.

The ear extends across the plane of the toggle link |4| and the upper end of the toggle link |4| engages the ear to limit the overcenter movement of the tripping toggle.

The tripping toggle |39|4| is adapted to be operated overcenter in a direction to cause its collapse to eiect tripping of the breaker by means of a tripping electromagnet including the coil 49 and a movable core member or armature |51. The armature |51 is secured on the end of a trip rod 59 which is slidably mounted in an opening in a stationary core |6| threadedly engaging a cross bar |63 of insulating material. The toggle link |4| is provided with an ear |64 with which the trip rod is adapted to cooperate to trip the breaker. The armature |51 is biased to its unattracted position by a spring |65 surrounding the trip rod |59 and compressed between the stationary core |6| and the armature The trip bar |49 extends across all of the poles of the breaker, and each of the outer poles is provided with a trip magnet identical with the previously described trip magnet 49|51 for the center pole. The cross bar |63 extends across -all of the poles and is supported by means of bolts |69 (Fig. 1) on ears |1| projecting from the frame members 55. The trip rods |59 for the outer poles are slidably supported in stationary cores (not shown) mounted in the cross bar |63, but which cores are identical with the stationary core 6| for the center pole trip rod. The trip rods |59 for the outer poles are adapted to cooperate with ears |13 (Fig. 1) on the arms |61 in order to operate the trip bar |49 to eiect tripoing of the breaker.

Normal current ilowing through the circuits of the several poles of the breaker will not energize the trip devices 25 suiliciently to overcome the tension of the springs |65 and cause tripping of the breaker. Upon the occurrence of an overload current in the circuit of any one of the poles the trip magnet for the affected pole will attract the armature V|51 (Fig. 2) and thrust the trip rod |59 toward the right. At this movement the trip rod engages the ear |64 of the toggle link |4|, or the ear |13 of one of the arms |61, depending upon the pole in which the overload occurs, and rotate the trip bar |49 and the toggle link |4| in a clockwise direction to cause collapse of the tripping toggle. As the tripping toggle |39|4| moves overcenter to collapsed position (Fig. 3), it no longer is effective to restrain the latch lever 65 in latching position to thereby restrain the bell crank 11. The springs 31 for the center pole, acting through the lever 96 and the roller 99 thereupon force the latch lever 95 further in unlatching direction to complete the collapse of the tripping toggle. This action of the lever 95 also initiates movement at the bell crank lever 11 in opening direction. The bell crank lever 11 is now free to rotate in a clockwise direction to eiect opening of the contacts.

It will be noted that the main operating toggle comprising the links 61 and 69 is overcenter above a line drawn through the

centers

31 and 15 and is limited in its overcenter movement in this direction by the end |15 of the toggle link 69 engaging the cross bar 13 of the toggle link 61. The three-link toggle, comprising the toggle links 61, 69 and the bell crank lever 11, is slightly overcenter above a line drawn through the

centers

31 and 19. Since the moment arm tending to rotate lever 11 clockwise is small, the friction of the parts alone may be suillcient to prevent collapse of linkage. As soon as the latch lever `is operated by the tripping toggle |39- |4| to free the bell crank 11, the springs 91 rotate the lever sharply clockwise until it is arrestedA by projections |11 (Figs, 1 and 2) thereon striking stops |19 projecting inwardly from the frame members 55. 'I'his limited movement of the lever 95, however, is suillcient to move the knee 15 of the toggle 61, 69--11 overcenter above the center line 31-19, whereupon the springs 91, acting through the contact levers 35, move the operating mechanism and the movable contact structure to open position illustrated in Fig.

3. The opening movement of the contact arms 39 and of the movable contacts is limited by projections |8| on the toggle links 61 striking the spacer 62 on the rod 60 which connects the frame members 55. During the opening movement and before the projections |8| engage the spacer 62, inclined surfaces |83 on the toggle links 61 adjacent to the projections |6| engage the spacer and cause the toggle 61--69 to move overcenter slightly below the center line 31-15.

The toggle 61-69 does not immediately completely collapse due to the springs ||1 which bias the manually operable lever |03 clockwise pressing the roller l| 5 against the left-hand end |15 of the toggle link 69 in a direction and with suilicientforce to prevent further collapse of the toggle 61-69 at this time.

Due to the pressure pivot contacts (Fig, 5)

with which the contact levers 35 for the several poles are mechanically (and electrically connected to the corresponding contact arms 39, and

by which the contact arms 39 for the several v poles are similarly connected to the ears 43 of the corresponding conductors 45, considerable static friction is present when the breaker stands in the closed position. Additional friction is created at the pressure contact upon the occurrence of a short circuit or a heavy overload due to the parallel iiow of current through the contact arms 39 and the contact levers 95 which results in magnetic attraction of these parts. This tends to increase the pressure of the contact arms 39 on the contact levers 35 and to increase the pressure of the contact levers 35 on the spacer 44 (Fig. 5). 'I'his friction is overcome at the beginning of the opening movement of the mechanism by the mechanical advantage of the contact levers 35. Referring to Fig. 2, it can be seen that the momentl arm 89-31 of the point of application of the force of the springs 81 to the levers 35 i; substantially greater than the moment arm 'ZI-31, that is, from the pivot pin 31 to the point of contact of the movable contact 2| with the stationary contact I9. After the breaker is tripped and the toggle 61, 69-11 is moved overcenter above the line 31--19, the force of the springs 81 for all of the poles is applied simultaneously to the lower ends of they contact levers 35 for the corresponding poles, and with the point of engagement of the movable contacts 2| with the stationary contacts I9 ai a iulcrum, and moves the contacts to open position. During the first part of the opening movement, the contact levers 35 rotate in a counterclockwise direction about their pivots 31 and thus provide a wiping and cleaning action between the movable and stationary contacts.

The counterclockwise movement of the con-- tact levers 35 is limited by engagement Qf the levers with pins |85 (Figs. 1, 2, 3 and 4) supported in the contact arms 39 and extending therebetween. After the contact levers 35 engage the pins |95, the contact arms 39 and the contact levers 35 for all of the poles move as a unit to the open position (Fig. 3).

After the breaker has been tripped and until thebell crank lever 11 is relatched by the latch lever 85, it is necessary that the tripping toggle |39-IM be held in its operated or ineffective position (Fig, 3) to hold the latch in released position. This is accomplished by movement of the lever 95 to start the toggle 61, 69--11 overcenter. At this time the free end of the lever 95 engages the upper end of the toggle link |39 of the tripping toggle and restrains the tripping toggle in the collapsed position, shown in Fig. 3, until the bell crank 11 is reset.

- The bell crank 11 is reset by movement of the operating handle |09 from its Fig. 3 position to its extreme counterclockwise position indicated by dotted lines at I09a (Fig. 4). During thi; movement, the roller I 5 on the inner end of the lever |03 engages the bell crank 11 at a point near its free end and rotates the bell crank therewith to the position shown in Fig. 4. Near the end of the counterclockwise movement of the bell crank, the roller 99 thereon engages the lever 95 and carries this lever therewith until the movement is arrested by the lever 95 striking the rod I|9. The rod I| 9 also limits the counterclockwise movement of the bell crank 11 and of the manual lever |03. Upon movement of the lever 95 from its Fig. 3 position to its Fig. 4 position, the free end thereof releases the tripping toggle link |39 whereupon the spring |53 acts to restore the tripping toggle to its overset position wherein the latch lever is effective to restrain the bell crank 11 in its latched position (Figs. 2 and 4).

Counterclockwise movement of the manual lever |03 to reset the mechanism carries the roller I I5 therewith away from the toggle 61-G9, but since in its Fig. 3 position the toggle is overcenter below the center line through 31--15, the

toggle follows to its collapsed position (Fig. 4)

projections I8! on the toggle links 61 engaging portions |91 of the frame members 55.

After the bell crank 11 has been relatched the contacts are closed by clockwise movement of 91-15. Since, at this time the pivot point 15 is fixed, due to the trip device restraining the bell crank 11, straightening of the toggle 61--99 effects closing of the contacts and tensioning of the spring 81. Continued movement of the toggle 51-99 in contact closing direction after the contacts touch causes the contact levers 35 to rotate in a clockwise direction about the pivots 31 up to dead center toggle and thereafter counterclockwise to fully closed position. thus causing a back and forth wiping action between the contacts 2| and i9 as the contact arms .39 move to fully closed position.

The circuit breaker may be locked in the closed or the open position by moving the manual oper ating lever to its extreme counterclockwise position |09@ (Fig. 4) and inserting a locking device through openings |89 (only one of which is shown) in projections I 9| of the cover i3. In this position the roller ||5 engages the bell crank 11 and prevents movement thereof in opening direction even though the trip device is operated in response to an overload current to unlatch the roller 8|.

The circuit breaker may not be operated to open the contacts by means of the manual operating handle |09, but may be tripped open manually by operation of a manual trip button |93 (Figs. 2, 3 and 4). The trip button |93 is carried on the outer end of a horizontally disposed rod |95 of non-conducting material slidably mounted in the lower part of the cover I3 and is biased to undepressed position by means of a spring |91 seated in a spring seat in the cover |3 and having one end bearing against the button |03. Outward movement of the rod |95 is limited by a collar |99 secured on the inner end of the rod engaging the inner surface of the cover I3. The inner end of the rod |95'1ies adjacent the counterweight I5! and, upon depression of the button |93, engages the counterweight and rotates the trip bar |49 and the tripping toggle link |4| in a clockwise direction to effect tripping of the breaker in the manner previously described. The spring |91 restores the trip rod |95 to its undepressed position upon release thereof.

`After the breaker is manually tripped open, the mechanism'is reset and the contacts closed by manipulation of the manual operating handle |09 in the previously described manner.

It will be seen that the operating spring provides the force for initiating movement of the operating toggle in opening direction, for complating the opening movement of the breaker, and also holds the breaker latch in released position until the mechanism is reset and supplies the contact pressure when the breaker is in the closed position.

Lfeatures of the invention. It is desired, therefore, that the language of the appended claims be given the broadest reasonable interpretation permissible in the light of the prior art.

We claim as our invention:

1. A circuit breaker comprising relatively movable contacts, a switch member movable to open and close said contacts, operating mechanism therefor including a releasable member restraining said switch member in closed position when the circuit breaker is in closed position, said member being movable from one position to a second position to cause opening ot said contacts, trip means operable in response to overload circuit conditions to release said releasable member. means cooperating with the releasable member to start movement of said member toward said second position, and resilient means cooperating with the starting means and said switch member to actuate the starting means and move said switch member to open the contacts.

2. A circuit breaker comprising relatively movable contacts, a switch member movable to an open and a closed position to open and close said contacts, operating mechanism therefor including a handle for moving said switch member to closed position, a member for restraining said switch member in closed position independently of said handle, said member being movable from one position to a second position to cause move-'- ment of the switch member to open position, trip means operable in response to overload currents to initiate movement of said member to said second position, actuating means cooperating with said movable member to start said member toward said second position, and spring means for operating said actuating means and for moving the switch member to open position.

3. A circuit breaker comprising relatively movable contacts, a switch member movable to open and closed positions to open and close said contacts, operating mechanism for said switch member including an operating handle, a pivoted member for restraining said switch member in closed position independently of said handle and movable from one position to a second position to effect movement of the switch member to open position, restraining means for said pivoted member operable in response to predetermined Pircuit conditions to release said member, means cooperating with said pivoted member to initiate movement thereof to said second position, and spring means for actuating said pivoted member and for moving the switch member to open position.

4. A circuit breaker comprising relatively movable contacts, a switch member movable to open and closed positions to open and close said contacts, operating mechanism including a toggle for restraining said switch member in closed position and operable to cause movement of said switch member to open position, a trip device for holding the toggle in operative position and operable in response to overload circuit conditions to release said toggle, means operable to start movement of said toggle in a direction to cause opening oi.' the contacts, and spring means for actuating said starting means and for moving the switch member to open position.

5. A circuit breaker comprising relatively movable contacts, a switch member movable to open and closed positions to open and close said con-- tacts, operating mechanism therefor including a toggle for restraining said switch member in closed position and collapsible to cause movement of the switch member to open position,

latch means for restraining said toggle against collapse, a trip device operable in response to overload circuit conditions to release said toggle, actuating means supported independently o! the toggle and operable to start said toggle in a collapsing direction to cause opening of the contacts, and common means for operating said actuating means and for moving said switch member to open position.

6. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including a member pivotally connected to the movable contact and movable from one position to a second position to cause opening of said contacts, latch means for restraining said member in said one position to hold the contacts closed, electromagnetic means operable in response to overload current conditions to release said movable member, an actuating member operable after said movable member is released to initiate movement of said movable member toward said second position, and a spring for operating said actuating member, said spring being effective to move said movable member to said second position.

7. A circuit breaker comprising relatively movable contacts, a switch member movable to open and closed positions to open and close said contacts, a contact lever pivotally carried on said switch member, operating mechanism for said switch member including a toggle for restraining said switch member in closed position, said toggle being collapsible to cause movement of the switch member to open position, latch means for restraining said toggle against collapse, a trip device operable in response to overload circuit conditions to effect release of the toggle, actuating means operable to initiate collapse of said toggle, and a spring for operating said actuating means, said spring being connected to the contact lever and biasing said contact lever in a direction to apply pressure to said contacts when the switch member is in closed position.

8. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including a releasable member pivotally connected to the movable contact for restraining said contact in closed position and movable from one position to a second positionv to cause opening of said contacts, latch means for restraining said releasable member in said one position, trip means operable in response to predetermined abnormal circuit conditions to operate said latch means to release said movable member, and an actuating member operable to initiate movement of said releasable member toward said second position, said actuating member when operated engaging the latch means to restrain said latch means in released position until said releasable member is reset to permit relatching oi said releasable member.

9. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including a toggle operable from one position to a second position to effect opening of said contacts, a latch for restraining said toggle in said one position and operable to permit movement of said toggle to said second position, trip means operable in response to overload circuit conditions for operating said latch, an actuating lever operable to initiate movement of said toggle toward said second position, and spring means disposed to operate said actuating lever and to move said toggle to open the contacts, said lever having a part engageable with the latch means for restraining said latch means in released position to permit relatching of said toggle.

10. A circuit breaker comprising relatively movable contacts, operating mechanism therefor includinga member` movable from one position to a second position to cause opening of said contacts, said member being resettable to said one position, a latch for normally restraining said member in said one position, aV trip device including a tripping toggle operable to release said movable member, an actuating member biased to initiate movement of said movable member toward said second position, and means on said actuating member for engaging said tripping toggle to hold the latch in released position to permit resetting of said movable member.

l1. A circuit breaker comprising relatively movable contacts, a switch member movable to open and closed positions for opening and closing said contacts, a 'contact member pivotally mounted on said switch member and carrying the movable contact, releasable operating mechanism operable to cause automatic opening of said contacts, means for restraining said operating mechanism in operative position, trip means operable in response to overload circuit conditions to actuate said restraining means to release said operating mechanism, actuating means operable upon release of said operating mechanism' to operate said operating mechanism a predetermined distance in opening direction, and a spring disposed to operate saidactuating means and to move the switch member to open position, said spring moving said contact member to cause a wiping action between said contacts during the first part'of the opening movement. a

12. A circuit breaker comprising relatively movable contacts, releasable operating mechanism therefor including a toggle operable to cause opening of said contacts, a trip device for restraining said toggle in closed position and operable in response to overload circuit conditions to release said toggle, and resilient means disposed to apply a force to a plurality of points of said toggle to initiate movement of the operating mechanism in opening direction and th`en to apply a force to a single point of said toggle to complete the opening movement of said operating mechanism, said spring being connected to the movable contact and eilective when the mechanism is in closed position to apply pressure to said contacts.

13. A circuit breaker comprising relatively movable contacts, a switch membermovable to open and closed positions to open and close said contacts, a contact lever pivotally carried on said switch member, operating mechanism for said 'gswitch member including a toggle for restraining paid switch member in closed position, said toggle being collapsible to cause movement of the switch member to open position, latch means for restraining said toggle against co1lapse,la trip device operable in response to overload circuit conditions to eilect release ofthe toggle. actuating means operable to initiate collapse of said toggle, and a spring for operating said actuating means and to then complete the collapse of said toggle and opening of said contacts, said spring having one end attached to the contact lever and biasing the contact lever in a direction to apply contact pressure when the switch member is in closed position.

14. A circuit breaker comprising relatively movable contacts, a switch member movable to open and closed positions to open and close said contacts, operating mechanism for said switch member including a toggle operable from one position to a second position to effect opening movement of said switch member, a.latch for restraining said toggle in said one position and operable to permit movement of said toggle to said second position, trip means operable in response to overload circuit conditions for operatf ing said latch, an actuating lever operable to initiate movement of said toggle toward said second position, and spring Ameans connected at one end to said actuating lever and at the other end to the switch member to operate said actuating lever and to move said toggle to effect opening movement of the switch member.

l5. A circuit breaker comprising relativelyv movable contacts, a switch member movable to open and closed positions to open and close said contacts, operating mechanism for said switch member including a toggle operable from one position to a second position to eiect opening movement of said switch member, a latch for restraining said toggle in said one lposition and operable to permit movement of said toggle to said second position, trip means operable in response to overload circuit conditions for operating said latch, an actuating lever having limited movement and operable to initiate movement of said toggle toward said second position, and spring means connected at one end to said actuating lever and at the other end to the switch member to operatev s: d actuating lever and to move said toggle to eiiect opening movement of the switch member.

16. A circuit breaker comprising relatively movable contacts, operating mechanism therefor including an operating lever movable to close the contacts, a toggle movable from one position to a second position to eiect opening of said contacts even though said operating lever is held in closed position, a latch for restraining said toggle in said one position and operable to permit movement of said toggle to said second position, trip means operable in response to overload circuit conditions for operating said latch, an actuating lever operable to initiate movement of said toggle toward said second position, and spring means disposed to operate said actuating lever and to move the toggle to effect opening of the contacts.

TURE LINDSTROM. PAUL O. LANGGUTH.