US2355075A - Circuit breaker operating mechanism - Google Patents

Description

Aug. 8, 1944. o; JENSEN 'CIRCUIT BREAKER OPERATING MECHANISM 4 Sheets-Sheet 1 Filed Jan. 15, 1941 FIG INVENTOk.-

BY z

I ATTORNEY Aug. 8, 1944. Q JENSEN CIRCUIT BREAKER OPERATJING MECHANISM Filed Jan. 15, 1941 -4 SheetsL-Sheet 2 Aug. 8, 1944. o. JENSEN 2,355,075

r CIRCUIT BREAKER OPERATING MECHANISM 7 Filed Jan. 15, 1941 4 sheets-sheets ll v H FIG. 4.

. INVENTOR.

. Y g y 2 Z 5 ATTORNEY.

Aug."8, 1944. o. JENSEN CIRCUIT BREAKER OPERATING MECHANISM 4 Sheets-Sheet 4 Filed Jan. 15, 1941 INVENTOR.

ATTORNEY.

Patented Aug. 8, 1944 CIRCUIT BREAKER OPERATING MECHANISM Otto Jensen, Glenside,

Circuit Breaker Company,

Pa., assignor to I. T. E.

Philadelphia, Pa., a

corporation of Pennsylvania Application January 15, 1941, Serial No. 374,414

8 Claims.

been complicated in construction and subject to excessive wear owing to the complex linking arrangements required. In the present invention, it has been found that a single collapsible toggle arrangement may be utilized for permitting the tripping of the circuit breaker; while the links forming the toggle arrangement, when in their extended form, may act as a single composite link for transmitting closing forces to the contacts of the circuit breaker.

An object of the present invention, therefore, is-

the formation of a closing mechanism for a circuit breaker where a single toggle arrangement may be utilized in the extended position of the links to transmit closing pressure to the contacts while the collapse of the toggle may permit opening of the contacts.

Still another object of the present invention is the formation and construction of supporting means for an extended toggle, which means may at all times be pivotally connected to other portions of the mechanism whether or not the toggle is extended or collapsed.

Another object of the present invention is the provision of novel latching means and novel means for removing the latches from supporting position either automatically or manually.

A further object of the present invention is the provision of toggle means which move beyond center for supporting the operating arm of a circuit breaker member in tion, while nevertheless permitting trip free action of the circuit breaker.

A corollary object of the present invention is the provision of automatic means for movingsaid closing toggle through center in order to collapse the same and permit complete opening of the circuit breaker.

These and many other objects of the present invention will be in part apparent and in part pointed out in the following description and drawings, in which:

Figure l is a cross sectional view of the circuit breaker and mounting and operating means therefor taken along a broken line parallel to the plane of movement of the contacts and closed circuit posimounted showing the entire mechanism in closing position.

Figure 2 is a view in perspective of the circuit breaker housing.

Fig. 3 is a view in perspective of the lower portion of the mounting structure and the base of the circuit breaker.

Figure 4 is a view corresponding to that of Figure 1 showing the contacts and operating mechanism in open circuit position.

Figure 5 is a view corresponding to a portion of that of Figures 1 and 4, showing the contacts and operating mechanism in trip-free position.

Referring now to Figure 1, the contact structure and the operating mechanism therefor are in a housing I which (as is seen in Figure 2) comprises a pair of side plates 2 and 3 interconnected by appropriate cross bracing means. The side plates of the housing carry, preferably integrally extended therefrom, a plurality of clamping means 4 and 5, each having a notch 6 arranged and spaced to engage the surface 1 of the vertical posts 8, 8 extending from the base 9 (see also Figure 3).

As is further seen in Figure 3, the vertical posts 8, 8 which support the entire structure, are secured to the side plates l0 and II of the base 9 by bolts I2 or any other suitable fastening means. The single simply formed base, shown in Figure 3 serves to support the entire circuit breaker structure. The posts 8 are wrapped with phenolic insulation l3, I3 which insulates those portions of the posts which extend above the top edges of the side plates I0 and I I of the base 9.

After the posts 8 and notches 6 are placed in registry with each other (Figs. 1 and 2), notched clamping members l5 may be placed over the edges 16 of posts 8 in juxtaposition with the integrally connected clamping members 4 and 5. Bolts ll may then be passed through suitable openings I8 in clamps l5 to engage the threaded perforations I9 in members 4 and ,5 in order effectively to secure the housing I to the posts.

The upper terminal 2| is secured in position by means of the clamping members 30 and 3| which have the same form as the clamping members 4-5 of the housing previously described and which are secured to the insulated vertical posts 8 in the same manner by means of the associated clamping members 32 and 33 and the bolts 34 and 35. The upper terminal 2| is connected to any suitable source of current by means of the connection members 31.

The lower terminal 40 is mounted in position by means of the bolts 4| which clamp the side plates 2 and 3 of the housing against it.

The upper extension 43 of the housing furnishes a suitable mounting for the arc quencher 44 which may be secured in position in any suitable manner and may have any appropriate form for extinguishing the are which may be drawn between the contacts.

The main movable contact 50 is pivotally mounted on the pin which is carried by the movable contact arm 52. This arm preferably comprises a pair of side plates interconnected by a cross plate in order to provide appropriate structural support for the contact mechanisms. The movable contact arm 52 is in turn pivotally mounted on the pin 53 which pin is supported between the side plates 2 and 3 of the housing The movable contact 50 has a contact surface 55 of suitable material such as a silver alloy which is engageable with a similar contact surface 56 mounted upon the end of the upper terminal block 2|. The movable contact 58 also has an additional contact surface 57 of similar material for engagement with a co-acting contact 58 mounted upon the lower terminal block 40.

The main movable contact 50 by this means, in the closed circuit position of the circuit breakor shown in Figure 1, forms an effective bridge contact between the upper terminal block 2! and the lower terminal block 40 for passing the current therethrough. The formation, operation and blow-on characteristics of these contacts are more fully described in Patent No. 2,150,566 of William M. Scott, J12, assigned to the assignee of this application.

In order to obtainthe necessary current carrying pressure between the contact surfaces 55 and 56 as well as between the contact surfaces 51 and 58, a compression spring 6!! is provided which is held in a socket 6| in the upper portion of the movable contact arm 52. This compression spring is connected to and bears against link 63 which is pivotally connected at 64 to the main contact 50.

The pressure of the compression spring 60 may be adjusted by the screw 65 in order to exert an appropriate clockwise and downward force upon the contact 50 to ensure the correct contact pressure. The clockwise force obviously ensures contact pressure between contact elements 5 and 56 while the concomitant downward force ensures appropriate contact pressure between the contact surfaces 51 and 58. In order to give effective operation to these forces the opening 5m in the contact 50through which the pin 5| passes is elongated somewhat in a vertical directicn as indicated by the dotted lines.

During the opening movement of the circuit breaker, hereinafter described in connection with the operation of the closing mechanism, it is important that the upper main contact surfaces be protected by adequate contacts electrically in parallel therewith. These latter contacts maintain engagement until after the main contacts have separated. The are resulting from the separation of the protecting contacts is then transferred to the arc chute and extinguished.

In order to ensure proper passage of the current to these shunt contacts and to limit the flow of current through the hinge pin a flexible conductor It is secured in any suitable manner, as, for instance, by the screws TI to the plate 13 of the movable contact carrying arm, the opposite end of the said flexible conductor being secured by the screws M to a portion of the lower terminal block 40.

This conductor carries the current through the shunt and arcing contacts during circuit interruption. A second conductor 15 is also secured at one end between conductor 10 and the lower terminal by screws 14, and its upper end is secured to the bottom of the moving contact 50. This conductor provides a circuit in shunt to the main lower contact 58 during contact opening to prevent arcing at this point as the contact pressure decreases.

An L-shaped arcing contact is secured in any suitable manner to the upper face of the contact carrying arm 52 and carries on a vertical face thereof a contact surface 8| engageable with an appropriate similar contact surface 82 which in turn is connected to the upper terminal block 2| in the manner hereinafter described.

A shunt contact 83 having a contacting surface 84 engageable with a corresponding contact surface 84' on the upper terminal block 2| is movably mounted upon and supported by the movable arcing contact 80 at one end of the lever 85 the opposite end of which pivots about the pin 86 on the movable arcing contact 89. The movable shunt contact 83 is urged into ccntacting position by the compression spring 81 which is held in any suitable manner as in an appropriate socket in the contact carrying arm 52.

The forward movement of the movable shunt contact 83 in response to the compression of the spring 81 is limited by an upward extension 87 of the movable shunt contact 82 which when the said shunt contact has moved away from the movable contact arm 52 an appropriate distance, engages the downward extension 88 of the arcing contact 80.

A flexible lead 89 secured between the arcing contact 80 and the upper surface of the contact carrying arm 52 extends to and is secured to the movable shunt contact 83 and thus in combination with the conductor 70 ensures a proper circuit connection between the shunt contact 83 and the lower terminal block 49 through the movable contact arm 52.

A magnetic blowout coil 9|! is cast integrally with the upper part of the terminal block 2| so that the lower end of the coil is integral therewith; the upper end 9| is secured by screws (not shown) to the terminal block. Special insulating means, including plate 92, electrically isolates that end of the coil from the terminal block itself.

A stationary arcing horn is removabl sccured to the coil end 9| in any suitable manner and extends around the coil to a position close to the movable arcing contact 80 when the circuit breaker is in closed circuit position. A flexible conductor I00 is clamped between the members 95 and 9| and is secured to the arcing contact |0| which carries the arcing contact surface 82.

An integral projection I02 of the interior of the stationary arcing horn 95 provides a knife edge bearing for the stationary arcing contact |0|, the notch I03 in the end of said arcing con-- tact |IJ| cooperating with the bearing N32.

The compression spring H3 urges the lower end of the stationary arcing contact |0|, which carries the contact surface 82 into engagement with the movable arcing contact surface 8|. The spring is recessed in a socket in the upper terminal block 2| and is insulated therefrom so that any current flowing through the arcing con-tact must necessarily pass through the flexible conductor I00, the coil end 9|, and thence from the upper terminal 2 I.

Within the coil 90 a cylindrical magnetic core H5 provides a path for the flux into the blowout pole pieces which are hereinafter to be described.

The entire movable contact arm 52 carrying the main movable contact 50, the shunt contact 83 and the arcing contact '80 is urged towards open position by a pair of tension springs I which provide for quick opening thereof. The said tension springs I20 are attached by means of the spring eyes I2I to side extensions of the pin 5| which pivots the movable contact 50. The opposite ends I22 of the springs I20 are'mounted on and secured to the ends of a cross bar I The cross bar is suitably dimensioned to engage in the notches I25 in the front edges of the side plates 2 and 3 of the housing I (see also Figure 2).

Adjusting and tensioning screws I26 are threaded through the cross-bars, the ends thereof bearing in sockets I21 in the bases of the notches I25. The adjustment of these screws regulates the tension of the spring and therefore the rapidity with which the contact arm will bring the movable contacts to open circuit position.

When the screws I26 have been adjusted, they may be locked in position by means of the lock nuts I28. It is obvious that when the circuit breaker contacts are open and the movable contact arm 52 has moved to Figure 4, the springs I20 are under the tension.

Accordingly, in connection with the be done at this time. breaker contact arm is in the open circuit position, the springs I20 may actually be assembled without the necessity of their being stretched,

The ends I2I of the springs are first connected to the side extensions of the pin 5I and the cross bar 823 is mounted in the notches I25 and the ends I22 of the springs connected thereto. Thereafter the screws I26 may be turned against the sockets I2'I thus stretching the springs to provide the required tension.

Obviously the further the cross bar is removed from the base of the notch, the greater the tension on the spring will be. The springs may thus be tensioned appropriately while the contacts least the assembly of the springs I20 circuit breaker may best are in the open circuit position so that the opening tension will be even greater when the contacts are thereafter closed and the springs further stretched.

The energy of the contact structure at the end of its opening movement is absorbed by a buffing mechanism I30 when the extension I3l of the contact carrying arm 52 strikes the surface of sliding block I32. The block I32 is slidable on cross-bar I33, a band of braking material I33 being interposed between the block and the crossbar. A braking shoe I34 supported by the bell crank lever I35, which in turn is pivoted on pin I36 bears against the band of braking material I34 on the opposite surface of the block. A compression spring I31 is interposed between the block and an arm of the bell-crank lever. It will be noted that as the end of the contact lever strikes the block causing it to slide, the movement of the block will cause the lever I to retate to increase the braking pressure on the block the position shown in In fact, when the circuit to halt the same. This provides for a simple buffer which has virtually no rebound and which thus tends to absorb the opening forces. The attributes and operation of this type of buffer are described in Patent No. 2,137,001 to Healis.

The movable contact carrying arm 52 is rotated around its fixed pivot 53 in a clockwise direction and against the tension of the springs I20 in order to close the contacts by the operating mechanism now to be described, which includes theprincipal operating arm I40.

The principal operating arm I40 is pivotally mounted on thefixed pivot pin I4I which is supported between the side plates of the housing. The upper end of the operating lever or arm carries a pin I4Ia on which pin is also mounted one end of the link I42. The link I42 carries at its opposite end, a pin I43 to which one end of the link I44 is rotatably secured. The opposite end I45 of the link I44 is pivotally attached to the contact carrying arm 52 by'being secured to the pin 5I between the sides of said arm.

Links I42 and I44 constitute a toggle arrangement which, when supported in extended position just beneath center in the manner shown in Figure 1, may be utilized to transmit a closing force from the operating lever I40 to the contact carrying lever 52; and which toggle arrangement may, however, when collapsed, permit the tension springs I20 to pull the contact carrying arm counterclockwise about the pivot 53 in order to effect an opening of the circuit breaker even if the operating lever is held in its circuit closing position.

Thus as seen in Figure 1, a clockwise rotation of the operating lever I40 will result, in a corresponding movement of the links I42 and I 44, in their extended and supported position as shown, to efiect a closing of the circuit breaker. A toggle supporting link I is pivotally mounted at one end on the pin I5I; and the opposite end is pivotally connected to the knee pin I43 of the toggle.

During the closing movement therefore, the toggle I42-I44 is supported in extended position in the manner shown in Figure 1 in approximate alignment. If during this movement or when the contacts are in closed position, the link I50 should for any reason fail to support the knee pin I43 of the toggle arrangement, then the toggles would collapse downwardly under the tension of the springs I20 and thus permit the springs I20 to open the contacts (Fig. 5).

For this purpose, it is essential that during the operation of the circuit breaker, the knee pin I43 of the toggle should not go beyond center that is to say that the toggles should never pass through a 180 angle with respect to each other.

The pivot I5I of the toggle supporting link I50 is mounted on the end of a bell crank lever I53 which is also pivoted on the housing pin I4I which supports the operating arm I40. The arm I55 of the lever I53 engages an adjustable stop I553 on a cross member I51 of the housing.

During the closing movement and while the contacts are closed, the fact that the knee pin I43 of the toggle is slightly below the straight line connecting the centers of the pins MI and SI causes a force to'be transmitted from knee pin I43 to the link I56 and the lever i53 tending to move these members downward and clockwise. That is, the force exerted by the springs 81, H0, and I20, which tend to collapse the toggle, has a component producing a downward thrust on the link I50 which component also has a tendency to rotate the link I50 and lever I53 clockwise.

The stop I55 positively limits the upward movement of the pin II and its downward movement is normall prevented by the latch lever I50. The angular relation of the toggle links is therefore, defined by three arcs: pin I4Ia about the fixed pin MI, pin I43 about the pin I5I, and pin 5| about the pin 53. Due to the fact that these radii may be unequal and that they need not be parallel, values may be selected which will control the relative angular position of the toggle links and hence, the strength of the component of the closing force that must be resisted by the latch.

The energy of any magnet used to release a circuit breaker latch is limited by its minimum energizing current. In the design of tripping systems it is usual to strive to control the forces required and those available to provide a suitable margin of safety. The acceleration and shock incident to closing may cause a latch to s ip out of en agement and must be considered.

The force carried by the toggle system of the present invention is a linear function of the closing movement caused by the stretching of the opening springs and an added function caused by the contact engagement This overall character istic produces a curve similar to that produced by the direct current solenoid which actuates the system.

From the above, it is seen that by properly selecting the radii, lengths and relative angles of the three levers, the latch pressure may be increased to the maximum allowable during the early part of the closing movement (to prevent slipping) and maintained at a safe pressure during the final closing action. The latch is therefore free from slipping and yet eas ly tripped at any time.

The forces described above may be greatly increased when a fault current is flowing through the breaker. Currents of a hundred thousand amperes and. more, produce large forces tending.

to force the contacts open. Under these conditions, there is ample energization of an overcurrent magnet to release the latch.

A latch lever 60 pivotally mounted on the pin I5! is arranged, however, to engage a roller I62 mounted by means of a needle bearing on the pin !5 I. A torsion spring not shown in the drawings but mounted on the pin urges the latch lever H50 in a counterclockw se direction to maintain its engagement with the roller I52.

The engagement of the latching portion of the latch i8 1 with the roller 252 is such as to prevent clockwise movement of the bell crank lever I53 and downward movement of the link I50 and therefore is such as to prevent the collapse of the toggle I42l44 thus preventing the springs I from causing the contact carrying arm 52 to swing about its pivot 53 to open the circuit breaker.

The use of a needle bearing on the latch roller I52 reduces the energy required to release the latch; and also, since the link #50 rotates about the latch pin during closing movement, the needle earing minimizes the frictional drag tending to impart this movement to the roller itself, which might affect its engagement with the latch lever.

Various manual or automatic means may be utilized to trip the latch- One form which is here illustrated may be of the type now known as ditions, the increasing strength of a rate-of-rise trip such as that more fully described in Patent 2,092,592 to Scott and which distinguishes between a short circuit and a suddenly applied load. In this form, the arrangement of the lower terminal block 40 provides for two current paths. A vertical extension I10 of the lower terminal block 40, defined by a cut-out I10 therein is surrounded by an overload magnet I1I the degree of energization of which depends on the current flowing through extension I10. An upper extension I of the terminal block 40 is surrounded by iron laminations I 8|. When the circuit breaker is carrying a steady value of current, the extensons I10 and I80 divide the load in proportion to the cross sect on of copper in the two paths. The iron plates IN and the overload magnet I1I are energized in proportion to the current which passes through the extensions which they surround. When there is a rapidly increasing current, the inductance, caused by the iron plates IBI, produces a counter electro-motive force in the path I80 and a much greater proportion of the current flows through path I10. The tripping current in path I 10 will thus be reached and the armature I 12 will be attracted before the total current reaches the setting of the breaker. This trip unit differentiates between a short circuit and a suddenly applied load. When a fault occurs the circuit has a very small inductance and consequently the current increases in value very rapidly. When a motor load is suddently applied, the inductance of the motor windings retards the increase of current so that the plates IBI have little effect.

Armature I12 is secured to a lever I13 which is rotatably mounted on a pin I14, and is restrained from motion towards the magnet ill by the tension spring I15. During over crrrent conthe magnet will attract the armature I12. When the rumture I12 is drawn sufiiciently close to the magnet "I it will strike the end of a tripping pin I18 which extends forward through an opening in the extension I10 and in the magnet Ill, to engage the lower end I82 of the latch lever I60. The movement of the tripping pin I18 occasioned thereby will cause a clockwise rotation of the latch I50 so that the upper end of the latch IE0 is moved out of engagement with the roller I62 thus permitting the toggles MZ-IM to collapse and the circuit breaker contacts to move to the open circuit position shown in Figure 5.

When, by this operation, the support of the latch lever I60 is removed from the roller I62, there is no further support for the bell crank lever I53 or for the link I50 so that the bell crank lever I53 may rotate clockwise and the link I50 may move downwardly in response to the collapsing pressure placed upon the toggles I42I44 by the tension springs I20 which have a component forcing the knee pin I 43 downwardly. The collapse of the toggles obviously, therefore removes any possible support which the contact carrying arm 52 may have against the tension of the springs I20 and the contact carrying arm will then rotate about its pivot 53 to the position shown in Figure 4.

A horizontal cross-bar M5 may be pro id d loosely supported in openings in the housing side plates and adjacent the lower end I82 oi" the latch lever just above the point with wh ch the tripping pin I10 is in abutment. Movement of this cross bar by hand or by any other suitable tripping apparatus may be utilized to cause the end I82 of the latch I60 to rotate in a clockwise direction about its pin I61 for the purpose of manually or automatically tripping the circuit breaker contacts open.

When the circuit breaker is in the open position shown in Figure 4, hand operating mechanism or any other suitable mechanism may be utilized for closing the contacts.

A preferred manual operating mechanism con.- prises the lever I90 which is rotatable about the pin I9I which pin in turn is supported between the side plates of the housing The hand operating lever I90 has at its free end a socket I92 into which a handle may be inserted for manual operation. The hand operating lever also has an integral extension I93 carrying pin I94 to which is pivotally connected the link I95. The opposite end of link I95 is at I99 pivotally connected to the actuating lever I91 which is pivotally mounted on the pin I4I carried between the side plates of the housing.

The lever I90 and the link I95 thus provide a toggle for forcing the actuating lever I91 in a clockwise direction about its pivot MI. The extension I93 of the lever I92 has a step 200 integral therewith which coacts with a stop 20I on the link I95 in order to limit the movement of the toggle so that the knee pin I94 of the toggle is over center when the stops engage.

The abutment 205 on the outer surface of the actuating lever I91 normally engages the adjustable stop 206 on the lower extension of the operating lever I40. The stop 206- preferably is a screw held in a suitably tapped perforation in the extension of the operating lever I40. and prevented from accidental turning by the lock nut 201.

A toggle re-setting spring 220 is connected at one end to the knee pin I43 of the toggle I42-- I44 and, at the opposite end, to the stationary pin 2I9. After the circuit breaker has tripped and the toggle I90-I95 has collapsed, in the manner hereinafter described, the spring 220 serves to reset the toggle I 42-I44 in the position shown in Figure 4 so that the circuit breaker is in position to be closed once more. I

The closing action (that is, the movement of the parts from the Figure 4 position to the Figure 1 position) may be either a solenoid closing action or a manual one which causes the actuating lever I91 to rotate in a clockwise direction about the pin I4I, causing the operating lever I40 likewise to rotate in a clockwise direction about the pin I4I, thus forcing the toggle I42- -I44 in its extended position towards the right (with respect to Figures 4 and 1). The pressure of the extended toggle I42-I44 upon the pin 5I of the contact carrying arm 52 will cause the contact carrying arm 52 likewise to rotate in a clockwise direction about the pin 53 and thus force the movable contact members carried by the contact carrying arm against the stationary contact members for the purpose of completing the circuit.

When, therefore, as is seen in Figure 4, a handle 230 is inserted in the socket I92 of the manual closing arm I90 and the manual closing arm I90 is with respect to Figure 4 rotated in a counterclockwise direction about the pin I9I, the toggle I90-I95 is caused to be extended in the manner shown in Figure 1 and the knee pin I94 of the toggle.I90-I95 is caused to move beyond center.

The movement beyond center of the knee pin I94 locks the actuating arm I91, and hence the I40, in closed circuit position and 20I on the toggle II95 prefrom breaking in the opposite operating arm stops 200 and ventthe toggle direction.

In the trip free position (shown in Figure 5), if for some reason the actuatinglever I91 and the operating lever I40 are held in closed circuit position either by the handle member, I90 or by any solenoid closiiigrnechanism the resetting spring 220. is not permitted to contract while nevertheless the toggle I4'2l44 has collapsed in order to permit a complete opening movement of the contact carrying member 52.

Upon the release of closing pressure from the manual closing lever I90 or from any solenoid mechanism which may be used for closing the circuit breaker, the re-setting spring 220 is permitted once more to extend the. toggle I42--I44 to permit the link I50 and the bell crank lever I53 to be again supported by the latch I60 and to move the operating arm I40. and the actuating lever I91 back to the position shown in Figure 4.

While there has been no interference in the movement of the circuitbreaker contacts to the trip free position shown in Figure 5, the operating arm I40 and the actuating arm I91 cannot returnto the original position shown in Figure 4, under the influence of the re-setting spring 220, until the toggle I90-I95 is collapsed.

The pin I94 of the toggle I90-I95 has been caused to move beyond center in order to provide a restraining force for maintaining contact pressure against the influence of tension springs I20. In order to. permit the operating arm and actuating lever to move back to open position, the toggle I90-I95 must be moved through center to the collapsed position shown in Figure 4.

At the end of the opening movement of the contact carrying arm 52 thedownward extension 240 thereof (see Figure 5) strikes the end 24! of an auxiliary lever 242 which is pivotedon the pin I9I. -A torsion spring I90 surrounding this pin has. one end engaging the auxiliary lever 242 and the other end engaging the arm I90 and normally holding them in engagement in the position shown in Figure 1. When this auxiliary lever 242 has by means of the extension 240 of the contact arm 52 been moved in a clockwise direction as shown in Figure 5, the torsion spring above mentioned immediately exerts a force tending. to raise the lever I90 and thus collapse the toggle I90-I95.

As soon as this is accomplished, the re-setting springs 220 are enabled to act upon the knee pin I43. of the toggle I42-I44 in the manner above described and the parts are automatically returned to the position shown in Figure 4 and the contacts can be reclosed manually.

, The opening of the contacts is extremely fast and thus the lower extension 240 of the contact carrying arm is moving rapidly. Since the auxiliary lever 242 isextremely-light and the torsion spring connecting it. to lever I90 is just strong enough to lift this lever, a seriousv shock due to a hammer blow is avoided. o p

The re-setting. operation is distinct from the opening operation. The opening operation causes a bias tending to initiate the re-setting, but the inertia of the locking toggle and the plunger (hereafter described) causes relatively slow starting of these parts. -The 're-setting is thus an automatic, subsequent. and relatively independent operation.

Various additional means may be utilized to simplify the operation and protect the various elements of the circuit breaker. Thus in order to ensure that the principal contact surfaces 51 of the movable contacts 50 and 58 of the lower terminal block 40 should at all times be protected from dirt and grit, a slidin contact block 300 is provided in connection with the movable contact 50. The sliding block is so arranged that when, as seen in Figures 4 and 5, the circuit breaker contacts are moved to open circuit position, the under surface of the sliding block 300 is in contact with the contact surface 58 of the lower terminal block 40.

The sliding block is pivotally mounted at 302 on the link 303, the opposite end of which link is pivotally supported at 304 on the contact block 59. Tension spring 305 is attached at one end to the pivotal mount 302 of the sliding block and at the other end to the pin 301 which i carried by the contact block 50. The force exerted by the tension spring is sufficient to maintain appropriate contact pressure between the sliding block 300 and the contact surface 58 when the circuit breaker is moved to open circuit position.

When the circuit breaker latch is tripped so that the contacts separate, the main contact surfaces 55 and 56 separate first. The shunt contact surfaces 84 and 84' separate immediately thereafter and the sequence of separation is such as to protect the main current carrying surfaces 55 and 56. At the same time the surfaces 51 and 58 separate and the sliding block moves into contact with the contact surface 58.

While the shunt contact surfaces 84 and 84' are separating the arcing contact surfaces 8| and 82 remain in contact and are the last to separate. An arc is drawn therebetween which by the blow out action of the coil 9|] is transferred to the gap between movable arcing contact 8| and the stationary arcing horn 95.

When the movable arcing contact 8| reaches the limit of its travel as seen in Figures 4 and 5, the arc is transferred to the arcing horn 343 which is in electrical communication with the lower terminal block 40 through the side plates of the housing. The arcing horn 340 is supported between the side plates by the transverse pins 34| and 342.

As is seen in Figure 4, the arc quencher 44 carries secured to the outside of the side plates thereof, pole pieces 350 of magnetizable material which pole pieces register on each side with the ends of the core I 5 of the blow out coil. Any magnetic field thus generated by the coil is transferred to the pole pieces 35!] which can then perform the necessary blow out action to cause the arc to travel upwardly on the arcing horns and into the arc quencher to be therein extinguished.

The are quencher and the pole pieces thereof may have any suitable form for extinguishment of the arc, the construction and operation thereof being varied in accordance with the requirements of the particular circuit breaker.

Magnetic closing means may be provided for the circuit breaker where that is desired, an appropriate closing coil being provided therefor.

A preferred construction illustrated in Figure 1 may be utilized. Since the housing structure of the circuit breaker is preferably formed of welded steel plates having high permeability, adequate flux paths can be provided by these plates with relatively low weight. Horizontal steel cross plates 360 and 36| are welded to the side plates to provide a magnetic coil chamber and also act as cross bracing for the housing of the circuit breaker itself.

A heavy back plate 362 is welded between the side plates and bored out at 363 to receive the plunger guide tube 364. This tube 364, the back plate 362 and the plates 360 and 36| define a coil chamber 310 surrounding the tube in which a cylindrical energizing coil may be located. The front end of the solenoid housing is closed by a heavy front plate 312 which is secured in position by cap screws 313 which may be threaded into the triangular lugs 314 (see Figure 2), which are welded into the frame. The side plates and 2 of the frame may be recessed at 315 to receive the front plate 312 and the top cross plate of the solenoid 360 may likewise be recessed for a similar reason at 316.

A notch 318 may also be provided in the bottom cross plate 36| of the solenoid housing also to provide appropriate clearance for the plate 312. The front plate 312 or head is drilled for the operating rod 380, so that the rod may extend into the chamber to connect with the solenoid plunger 38| while the opposite end of the said rod is connected by the yoke 382 to the pin 383 at the lower end ofthe actuating lever I91.

The energization of the closing coil 31| will cause the solenoid plunger 38| to be drawn into the coil thus causing the operating rod 38| to move towards the left with respect to the figures, thus causing the actuating lever I91 to rotate in a clockwise direction, in the same manner as previously mentioned in connection with manual closing for effecting a closure of the circuit breaker.

The opening action of the circuit breaker members and the restoration of the actuating lever I91 to the open position shown in Figure 4 will result in a reverse movement of the solenoid plunger causing the same to move towards the right. In order to avoid a hammer blow on the head of the solenoid chamber, the air in portion 400 of the chamber may be effectually sealed therein by the solenoid plunger 38| which acts as a. piston. The compression of the air provides a cushioning effect during the latter part of the closing stroke. A pressure relief valve in the back of the plunger permits a gradual escape of this air.

In order to permit a relatively rapid return of the plunger during resetting, a check valve 4|l| and communicating air passages 462 may be provided in the solenoid plunger itself.

.It may be desirable 01' necessary that the opening or closing of the circuit breaker result in other switching or indicating operations or it may be necessary to energize relays when the circuit breaker is actuated. Accordingly, switching means 426 may be provided. This is secured to the base of the housing and has a rotatable actuating arm 42| connected by a pin 422 to the vertical link 423 which link is adjustable at 424. The opposite end of the link may at 425 be connected to a pin on the bell crank lever 426 which is pivoted on the stationary pin 53.

The end of the bell crank lever 426 opposite the end 425 thereof may at 428 be connected to a pin on the contact carrying arm. The movement of the contact carrying arm to open position will cause the bell crank lever 426 to rotate in a counter clockwise direction, thus causing the end 425 thereof to be depressed, thus depressing the link 423 and causing the operating arm 42| of the switch 428 to rotate in a counterclockwise direction to actuate the relay or switch in any appropriate manner. The closing of the circuit breaker will cause a reverse operation of the switch or relay 42H.

In the foregoing description, the operation of the various members of the circuit breaker have been set forth in connection with the description of each member.

The various linkage mechanisms which per mit the operation of the circuit breaker and the different variations thereof which may be possible should now be clear to those skilled in the art. It is preferred therefore to be bound not by the specific disclosure herein set forth but only by the appended claims.

I claim:

1. In a circuit breaker operating mechanism, a pivoted switch member biased toward open circuit position, a lever for moving said switch member to closed circuit position; a single toggle mechanism for operating said switch member to closed position against its bias, said single toggle comprising a collapsible thrust transmitting mechanism comprising a first link having one end pivotally mounted on said switch member, a second link having one end pivoted to said lever, the other ends of said two links being pivoted together, said first and second links be ing substantially in a straight line but below the center to center line from the pivot points of said first and second links while said lever transmits power therethrough to operate said switch member to closed position, and a third link connected atone end to the common pivot of said first two links; said third link extending almost at right angles to said first two links; the other end of said third link being connected to a releasably supported pivot; the distance from said common pivot point to the center-to-center line being controlled by said third link in accordance with said bias on said switch member.

2. In a circuit breaker operating mechanism, a contact carrying member biased from a closed to an open position, a lever for actuating said member, collapsible toggle means for connecting said lever and said member for movement thereof against said bias, a manually controlled toggle for moving said lever against said bias, said last named toggle having its knee pin over center at the end of the closing movement to maintain said lever in position, a pivoted member resiliently connected by means of a spring to said toggle; and a member on said contact carrying member engageable with said pivoted member during the opening movement; said last mentioned member engaging said pivot member during the opening movement and through the resilient connection, moving said last named toggle through center and collapsing the same.

3. In a circuit breaker operating mechanism, a contact carrying member biased from a closed circuit to an open position, a lever for actuating said member, a thrust transmitting toggle connecting said member and said lever, disengageable means for supporting the knee pin of said toggle and normally preventing the collapse thereof, a spring connected to said knee pin of said toggle to effect the resetting thereof and the reengagement of said supporting means after disengagement thereof, means for moving said lever against said bias and for maintaining said lever in position comprising a second toggle having its knee pin over center at the end of the closing movement, means associated with said contact carrying member and said last-named toggle for effecting collapse of said toggle upon movement of said member to open position, said spring then being effective to cause said resetting and reengaging action.

4. In a circuit breaker operating mechanism, a contact carrying member biased from a closed circuit to an open position, a lever for actuating said member, a thrust transmitting toggle connecting said member and said lever,-disengageable means for supporting the knee pin of said toggle and normally preventing the collapse thereof, a spring connected to said knee pin of said toggle to effect the resetting thereof the reengagement of said supporting means after disengagement thereof, means for movingsaid lever against said bias and for m; intaining said lever in position comprising a second toggle having its knee pin over center at the end. of the closing movement, means associated witl'i said contact carrying member and said last named toggle for effecting collapse of said toggle upon movement of said member to open posi tion, said spring then being effective to cause said resetting and reengaging action, said contact carrying member being movable once more to closed circuit position upon resetting of said thrust transmitting toggle and reengagement thereof with its supporting means.

5. In a circuit breaker operating mechanism, a pivoted switch member biased toward open position; a lever for moving said switch member toward closed position; a single toggle mechanism comprising a first and a second link; means whereby said lever operates said switch member to its closed position through said toggle mechanism; said links being in approximate alignment but below the center line connecting the pivot points of said first and second links Whereby a downward collapsing force is normally produced at said toggle mechanism during said closing operation of said circuit breaker; a supporting mechanism for said toggle mechanism at its midpoint extending substantially at right angles to said links; said supporting mechanism controlling said toggle during the entire closing movement; and means responsive to circuit conditions for removing said supporting mechanism whereby said toggle mechanism collapses to permit said circuit breaker operating mechanism to operate under its bias to open position.

6. In a circuit breaker operating mechanism, a pivoted contact carrying member biased toward open position; a pivoted operating lever; a toggle .mechanism having one end pivotally supported on said operating lever and the other end on said contact carrying member; means for normally locking said operating lever against movement; means for normally supporting said toggle against collapse; means for removing said support; spring means operative on the removal of said support for collapsing said toggle mechanism about said locked operating lever for moving said contact member to contact disengaged position; means responsive to the movement of said contact car rying member for removing the lock on said operating lever, means for rocking said lever about its pivot and for restoring said toggle mechanism for transmitting power to said contact carrying arm, means for thereafter operating said lever about its pivot for operating said contact arm through said toggle to its circuit closing position and means whereby on completion of the movement of said contact carrying arm to closing position said operating lever is again locked in position against rotation.

7. In a circuit breaker operating mechanism,

a pivoted contact carrying member biased toward open position; a pivoted operating lever; a toggle mechanism having one end pivotally supported on said operating lever and the other end on said contact carrying member; means for normally locking said operating lever against movement whereby said toggle mechanism is collapsible about its fixed pivot on said operating lever for moving said contact member to its open position; means responsive to the opening of said contact member for unlocking said operating lever to permit it to rock on its pivot for resetting said toggle mechanism; and means for operating said operating lever to its original locked position for operating said contact member through said toggle to its closed position.

8. In a circuit breaker operating mechanism, a pivoted switch member biased toward open position; a lever for moving said switch member toward closed position; a single toggle mechanism comprising a first and a second link; means whereby said lever operates said switch member to its closed position through said toggle mechanism; said links being in approximate alignment but below the center line connecting the pivot points of said first and second links whereby a downward collapsing force is normally produced at said toggle mechanism during said closing operation of said circuit breaker; a supporting mechanism for said toggle mechanism at its midpoint extending substantially at right angles to said links; said supporting mechanism controlling said toggle during the entire closing movement; means responsive to circuit conditions for removing said supporting mechanism whereby said toggle mechanism collapses to permit said circuit breaker operating mechanism to operate under its bias to open position; and means responsive to the operation of said circuit breaker mechanism to open position for resetting said collapsed toggle mechanism to substantial alignment whereby said lever is operative through said toggle mechanism for operating said circuit breaker to closed position.

OTTO JENSEN.

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