US2590634A - Circuit breaker - Google Patents

Description

March 25, 1952 CIRCUIT BREAKER Original Filed June 9, 1944 5 Sheets-Sheet l L e012 E. L z/dzaz'g, MIZ/iam A. S11/diem arid Gay/76W BY 1MM ATTORNEY March 25, 1952 L R. LUDWIG ET AL 2,590,634

CIRCUIT BREAKER @riginal Filed June 9, 1944 5 Sheena-.'s'neeL 2 ATTORN EY Mal'Ch 25, 1952 L R, LUDWIG ET AL CIRCUIT BREAKER @riginal Filed June 9, 1944 5 mena-'Sheet zal gg INVENTORS .6027 i?. L Udwig, William /f SIZ/@[23:71

and 60g/Na. Gaf/zel.

TTORN EY Patented Mar. 25, 1952 CIRCUIT BREAKER Leon R. Ludwig, Buffalo, N. Y., and William H. Stuellein, East McKeesport, and Gayne D. Gamel, Verona, Pa., assignors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Original application June 9, 1944, Serial No.

3, 1948, Serial No. 42,314

This invention relates to circuit breakers and, more particularly to circuit breakers embodying electromagnetic tripping means for instantaneously tripping the breaker in response to overload currents above a predetermined value and after a time delay in response to overloads of lesser value.

This application is a division of copending application Serial No. 539,450, filed June 9, 1944, by Leon R. Ludwig, William H. Stuellein, and Gayne D. Gamel, now Patent No. 2,504,855, issued April 18, 1950, and assigned to the assignee of the present application.

An object of the invention is to provide a circuit breaker having an electromagnetic trip device embodying an improved, adjustable timedelay device.

Another object of the invention is to provide a circuit breaker having an electromagnetic trip device with a mechanical time-delay device embodying a simple adjusting means for selectively adjusting the amount of time delay provided by the time-delay device.

Another object of the invention is to provide a circuit breaker having an electromagnetic trip device embodying a time-delay device comprising an adjustable mechanical escapement mechanism.

Another object of the invention is to provide an electromagnetic trip circuit breaker embodying an improved time-delay device that is of simple and rugged construction, accurate and 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 one embodiment thereof when read in conjunction with the accompanying drawings, in which:

Figure l is a vertical sectional view through the center pole of a three-pole circuit breaker.

embodying the principles of the invention; p

Fig. 2 is an enlarged vertical sectional view of the trip mechanism;

Fig. 3 is a horizontal sectional view of the trip mechanism taken on line III--III of Fig. 2, shoW- ing the time-delay device;

Fig. 4 is a sectional view taken on line IV-IV of Fig. 2;

Fig. 5 is a fragmentary view partly in section on line V--Vvof Fig. 2 showing the latch mechanism;` Y

11 Claims. (Cl. 2011-97) Y:rigidly connected by a cross member I9.

Divided and this application August Fig. 6 is a sectional view taken on line VI--VI of Fig. 2 showing the cooperation of the latch member with the tripping toggle; and

Fig. '7 is a sectional view taken on line VII-VII of Fig. 2.

Referring to Figure l of the drawings, the circuit breaker is provided with an operating mechanism common to all of the poles of the breaker. in a U-shaped frame l1 having sidesv which are The frame l1 is mounted on the central portion of a base Il of insulating material and is secured thereto by means of bolts 2l and 23. The outer ends of the frame are rigidly connected by a cross member 25.

A shaft 29 extending through openings in the sides of the frame l1 pivotally supports a pair of contact-arms 3l having their free ends integral with a contact-arm 3D for the center pole. The contact-arms (not shown) for the outer poles of the breaker are identical with the contact-arm 30 for the center pole, but are not provided With arms 3l. The contact-arms for the outer poles are rigidly secured to a tie-bar 61 .which extends across all of the poles and which is securely clamped toA the center-pole contactarm 30 by means of split clamp 10 and a screw 1|. The three contact-arms are thus mechanically connected for movement together. Recf tangular tubes B9 of insulating material between the tie-bar B1 and the contact-arms 30 for the several poles serve to insulate the three movable contact-arms and their associated contacts from the tie-bar B1.

The movable contact structures and the star tionary structures for the several poles are alike;

hence only the contacts for the center pole are illustrated. The contact-arm 30 pivotally carries a main movable contact-member 41 and a movable arcing contact-member 55 which cooperate respectively with a main stationary contact 39 and a stationary arcing contact 31. The stationary contacts 39 and 31 are secured to a conductor 4I which extends through an opening in the base l l and forms a terminal-connector 45. Contact pressure for the main contacts is provided by a spring 53 disposed between the contact-arm 30 and the main movable contact-member 41.

Similarly, a spring B3 provides contact pressure- 18 Where it is cooled and extinguished. vAny The operating mechanism is mounted suitable arc-extinguisher may be employed, the one shown comprising, generally, a stack of slotted plates (not shown) of magnetic material disposed adjacent the path of travel of the arcing contact-member 55.

The movable arcing contact-member '95 is connected by a iieXible shunt conductor 'l' to the main movable contact-member lil, and another flexible shunt conductor '5S connects the contactmember 41 to a conductor 8|'. The conductor 8| extends downwardly forming the energizing means for a tripping electromagnet (to be later described) and is secured at its lower end by means of a bolt 32 to the inner end of a terminalconnector 93 which, together with the terminal-l connection t5, serves to connect the breaker in an electrical circuit.

The electrical circuits for the several poles of the breaker are essentially the same. The circuit for the center pole extends from the terminal 45 through the conductor lil, the main contactmembers Sii-el, the flexible shunt conductor 79, the conductor 8| to the terminal 83. The circuit for the arcing contacts 3?-55 extends from the terminal d5, through the conductor ill, the arcing contact-members :l- 55, the flexible shunt conductor Tl, the main contact-member lil', and

through the previously described circuit to the terminal 83.

' The contact-arms 39 are biased in a clockwise orv opening direction by means of a pair of springs 85 (only one being shown). These springs are tensioned between the center-pole contact-arm 30 and a fixed pivot 8l supported in the main frame In the closed position of the breaker, the center-pole contact-,arm and consequently all ofthe contact-arms are releasably restrained in the closed contact position by means of a toggle and linkage mechanism which is collapsib-le to cause opening of the contacts. The toggle and linkage form a part of the common operating mechanism.

This collapsible linkage includes a yoke-shape lever 89 pivotally mounted on a fixed pivot 9| supported on the main frame il. The lever |39 is operatively connected to the support arms 3| of-the center-pole contact-arm 39 by a main operating toggle comprising toggle- links 99 and 95. The toggle-link 93 has one end pivoted on a pin |i| supported on the lever S9, and the link Sliv is pivoted on a pivot pin 99 in the arms 3|. The links 93 and 95 are pivotally connected by a knee-pivot pin 9i. The toggle-link 95 comprises a pair of links rigidly connected by means of an integral cross-bar H5.

The free end of the lever Se is pivotally connected by means of a link |93 to one arm of a lever |95 pivoted on the xed pivot 8i. The other end vof the lever |05 is pivotally connected to a toggle-link |97 of a tripping toggle comprising the link |91 and a toggle-link |09. The link liii is pivoted on a fixed pivot ||3 supported on the frame I'i. The toggle-links lli'l and id@ are pivotally connected by a knee-pivot pin i i i. The lever |915 and the link |03 each comprises a pair of membersrrigidly connected by yokes substantially as illustrated.

The above-described linkage serves to releas- .ably hold the contact structure including the movable contacts for all of the poles of the breaker in closed contact position. In the closed the other link of which comprises the lever 99, is overcenter above a line through the centers of the pins 99 and 9|. The overcenter movement of the main operating toggle 93-99 is limited by the projecting end of the link 93 engaging the cross-bar H9 of the link 95.

With the main operating toggle 93--95 and the toggle comprising the links 93--95 and the lever 89 in the overcenter position, the springs 29 bias the lever S9 in a clockwise direction. Clockwise movement of the lever t9, however, is normally prevented by the tripping toggle Nil-H29 which is restrained in a slightly underset position by a latch member lli (Figs. 1, 2 and 5) cooperating with an extension i9 of the toggle-link |67. As will be described hereinafter, the latch-member lil may be operated to release the extension H9 and permit collapse of the toggle Nil-|99 and opening of the contacts. In its restrained position, the tripping toggle itl- 499, acting through the lever H35 and the link |93, prevents clockwise movement of the lever l, and consequently holds the movable contacts in closed position against the biasing iniiuence of the springs 85.

The latch-member Hl is adapted to be actuated to cause collapse at the tripping toggle to effect opening of the contacts by means of an overload-trip device indicated generally at |33, or by` a shunt-trip device indicated generally at |39. The overload-trip device |33 is operable in response to overload currents in the 'circuit of the breaker to rotate the latch and cause collapse of the tripping toggle itllea The shunt-trip device is adapted to be energized from any suitable source separate from the circuit of the breaker to move the latch axially and cause the collapse of the tripping toggle Mil-|09 independently of the overload-trip device |33.

When rotated by the trip device |33, or moved axially upwardly by the trip device |38, the latchmember releases the extension H9 of the toggle-link |i'i and permits collapse of the tripping toggle itil-|99 which permits clockwise rotation of the lever 89 thus permitting the springs 95 to actuate the movable contact structure clockwise (Fig. l) to open the contacts.

The main operating toggle .9S- 95 does not immediately collapse, but the force of the springs applied through the contact-arms Sil- 3| and the main operating toggle causes collapse of the toggle comprising the links 93-95 and the lever.

89 which results in a clockwise movement of the lever 89. This movement is transmitted through the link |93 and the lever |95 to complete the collapse of the tripping toggle lill-H99.

The clockwise or opening movement of the contact-arms 39-3l is arrested by projections (not shown) thereon striking the frame ll. At this time, the rebound of the inertia of the mainoperating toggle 93-95 and the parts of the linkage 89, |03 and W5 starts the main-operating toggle 93-95 over center in a direction to cause its collapse. By the time the kneey pin Si of the toggle has passed over center below the line 99-|9|, the weight of the parts acts to complete the collapse of the toggle 93--95 and causes the linkage t9, |63, |95 and the tripping toggle Mil-W9 to be automatically reset to their normal holding positions and relatched. lIhe main toggle 93-95 remains in collapsed condition until the contacts are closed.

The contacts are closed manually by clockwise rotation of the handle Ml. This movement of the handle, through connections not shown, thrusts a link |5| downwardly, and, due tothe engagement of the link with a projection |53 on a yoke-shaped closing lever |45, rotates the closing lever in a clockwise direction. The closing lever |45 comprises a pair of spaced levers disposed on the outside of the frame |1 and are pivotally supported on the xed pivot 9|. Clockwise movement of the closing lever |45 engages a roller |55 pivotally carried on the inner end of the lever with the toggle link 93, now in its collapsed position, and moves the toggle 93-95 to its overcenter position. Since at this time the tripping toggle |91-|99 has been restored to its holding position and relatched, rotation of the lever 89 is prevented, and consequently the force applied by the roller |55 to straighten the operating toggle 93-95 rotates the contact-arms 39 counterclockwise to close the contacts and tension the springs 85. n

y The handle I4| is restored to its normal position by means of a spring |59 tensioned between the closing lever |45 and the frame l1. Upon release of the handle following a closing operation, the spring |59 moves the closing lever |45 counterclockwise and, through the projection |53 and link |5|, restores the handle |41 to its normal position.

The closing lever |45 may also be operated to automatically close the contacts through the agency of a motor |39 mounted on a plate (not shown), but which is attached to the side of the frame |1. The motor |39 may be energized from any suitable source, and when energized is adapted, through a suitable driving connection, to rotate a crank disc |39. The disc |39 carries an anti-friction roller |3| which, upon rotation of the disc, engages a cam face |32 on an arm |34, secured vto the closing lever |45, and rotates the arm and the closing lever clockwise to effect closing of the contact-s.` As soon as the roller 3| passes out of engagement with the arm |34, the spring |59 acts to restore the lever |45 to its normal position. The motor |39 is deenergized by a suitable limit switch (not shown).

The circuit breaker may be tripped manually by rotation of the handle |4| through a small angle in a counterclockwise direction from its neutral position. Rotation of the handle |4| in tripping direction engages a projection |51 on the link |5| with an ear |6| formed on a plate |93 (Fig. 2) secured to a slide |65 disposed in an opening in the cross-member 25 of the frame |1 and slidable vertically on a pair of rods |61 mounted in the cross-member 25 of the frame. The lower portion of the slide |65 is formed over to provide a laterally extending part |99 which is adapted to engage a head |1| on the end of a projection |13 integral with or otherwise suitably attached to the latch member ||1. Upon rotation of the handle |4| (Fig. l) in tripping direction, the link |5| is moved upwardly. During this movement, the projection |51 (Fig. 2) engages the ear |9| and raises the slide |65. This movement engages the extension |69 with the head |1| and raises the latch member ||1 to effect release of the tripping toggle |91-|99 and opening of the contacts.

As previously set forth, the latch member ||1 is rotated to release the underset tripping toggle |91-|09 by means of the current-responsive trip-device |33. There is a trip-device |33 provided for each pole of the breaker, but since the trip-devices for the several poles are alike only the one for the center pole shown in Figs. 2 and 3 will be described.

The trip-device |33 (Figs. 2 and 3) includes a fixed magnetic core-member |15 provided with pole-pieces |11 secured thereto by means of bolts |19 which also serve to clamp the parts to an insulating frame |8|. The core-member |15 is sur- .rounded by an insulating tube |83 to insulate it from the energizing conductor 8| which is looped around the core-member between the pole-pieces |11. The frame |8| .is provided with a crossmember integral therewithwhich is secured to the base of the breaker by means of the bolt 82 by which the conductor 8| and the flexible conductor 19 are secured together and to the base Mounted for rotation in the frame |9| is a shaft |81 having the legs |99 of a yoke or trip-bar |9| mounted thereon for movement relative thereto, the trip-bar |9| being operable by t-he trip-devices for all the poles. A headed and shouldered stud |93, secured to the yoke |9| by a nut |95, projects through an opening in a link |91 which connects the trip device to a time-delay device indicated generally at 2 I3. The inner end of the link |91 is formed over at right angles as at |99 to cooperate with an armature 29| mounted on the shaft |81 for movement relatively thereto. The armature 429| is biased to unattracted position as shown in Fig. 2 by means of a spring 293 having one end attached to a spring-clip 295 secured to the free end of the armature and the other end attached to an adjustable member 291. The member 291 has a reduced portion disposed in a vertical slot 299 in the outer wall of the frame |8| and is provided with a thumb-screw 2|`| for clamping the member 291 in its adjusted position in the slot 299. By loosening the thumb-screw 2|| and sliding the member 291 in the slot 299, the tension of the spring 293 may be varied thereby varying the minimum current value at which the tripdevice will function to trip the breaker.

The trip-devices for the two outer poles of the breaker are the same as the trip-device for the center-pole with the exception that the yoke or trip-bar |9| is omitted and the armatures 29| for the outer poles are secured to the corresponding shafts |81 for movement therewith. On the end of the shaft |81 adjacent the center-pole tripdevice is secured a collar 2|5 (Fig. 3) having a projection 2|1 thereon which is adapted to engage a shoulder on a connector Z of insulating material. The connector 2|9 is secured to a hub 22| which is rotatably mounted in a bearing in the side-Wall of the frame |8| and is secured to the leg |99 of the yoke |9| for movement therewith. Two connections 2|9 are provided, one disposed on each end of the yoke |9| for operatively connecting the two outer pole-armatures 29| to the yoke so that any one of the armatures will operate the yoke, upon energlzation of its corresponding trip-magnet, without displacing the other armatures.

The link |91 (Fig. 2) comprises two members Welded or otherwise suitably secured together at their left-hand ends and having their right-hand ends formed to straddle a ratchet-wheel 223 (Figs. 2 and 3). The ratchet-wheel 223 is rotatably sup.- ported in a housing comprising spaced-circular plates 225 and a cylindrical side-wall 221. The upper plate 225 is secured to the lower leg of a U-shaped bracket 229, which supports the shunt trip-device |38, by means of a pair of bolts 23| and is spaced from the bracket by spacers 233 surroundingthe bolts 23i (see also Fig. 4). The upper leg of the bracket 229Y-is securedwto the spaced main frame-members of the circuit breaker by means of a pair of screws 235` (only one being shown) and a pair of bolts 231 which extend through both plates 225, both legs of the U-shaped bracket 229 and threadedly engage the frame-members I1. Spacers 239 (Figs. 2 and 4) surrounding the bolts 231 serve to space the timedelay housing from the lower leg of the bracket 229 and spacers 24| (Figs. 2 and 3) also surrounding the bolts 231 space the upper and lower platesv `of the time-delay device-.housing apart. The plates 225 are alsorigidly joined by a headed screw 243 (Fig. 2) which passes through an opening in the lower plate and threadedly engages the upper plate 225. Surrounding the .screw 243 is a sleeve 245 upon which is mounted a shouldered sleeve 241 supporting the ratchet-wheel 223.

As previously stated, the bifurcated end of the link |91 straddles the ratchet-wheel 223. The link |91 is connected to the ratchet-wheel by means of a pin and slot-connection comprising a pin 249 (Figs. 2, 3 and 4) which extends through both .portions of the link |91, through an elongated slot 25| (Fig. 3)v in the ratchet-wheel 223 and through a clearance-opening 253 (Fig. 4) in the upper plate 225 of the housing of the timedelay device. The lower end of the pin 249 is headed and a collar 255 threadedly engages the pin above the upper portion of the link |91 to retain the pin 249 in place in the assembly. The pin 249 projects through the clearance-opening 253 in the upper plate 225 for the purpose of rotatably actuating the trip-member ||1 (Fig. 2) to trip the breaker in a manner more fully described hereinafter.

A spring 251 (Figs. 2 and 3) coiled about the sleeve 241 has one end hooked around the pin 249 and the other end hooked over the ratchetwheel 223 in the manner shown in Fig. 3. Normally the spring 251 is not under tension, but when the link |91 is moved toward the left (Fig. 3) by the operation of the electromagnetic tripdevice of any one of the poles of the breaker, the pin 249 places the spring under tension in a direction to cause counterclockwise rotation of the ratchet-wheel 223. The speed of rotation of the ratchet-wheel is governed by an oscillator 259, the two arms of which alternately engage the teeth of the ratchet in the usual manner.

'I'he oscillator 259 is U-shaped and is mounted for oscillation on a pin 26| which is mounted in the legs of a U-shaped movable member 263 pivoted on the ends of the sleeve 245 surrounding the screw 243. The spaced ends of the upper leg of the oscillator 259 are formed downwardly as at 255 (Figs. 2 and 3) to engage the ratchet-wheel.

The lower leg of the oscillator extends to the left p,

to form a governing weight for the oscillator, a clearance opening being provided therein for clearing the sleeve 241.

The amount of time delay provided by the time-delay device is adjustably determined by adjusting the oscillator circumierentially relative to the ratchet-wheel. This adjustment is effected by rotating the member 263 in which the oscillator is mounted about its pivot on the sleeve 245. This adjustment is accomplished by means of a kthumb-screw 251 having a threaded portion extending through an elongated annular slot in the sidewall 221 of the housing and threadedly engaging the yoke of the member 233. By loosening the thumb-screw 251 and rotating the U- shaped member 263 counterclockwise or clockwise, the oscillator is correspondingly moved in the same direction from the position in which it is shown in Fig. 3, respectively, lengthening or shortening the time delay.

As previously stated, the pin 2,49 projectsthrough the clearance-opening 253 (Fig. 4) in the upper plate 225 of the time-delay device housing to operate the latch-member |I1 and eiect tripping of the breaker. The latch-member I.-|1 is rigidly secured on the upper end oa trip .rod 259 which extends vertically through the center of the shunt trip-device |38. A disc 21| secured on the lower end of the rod 269 is provided with two recesses 213 and 215 (Fig. 4). The pin 249 (Figs. 2, 3 and 4) extends upwardly through the recess 213 and a substantial distance above the disc 21|. The side-walls of the recess 215 are adapted to engage a stop-stud 211 which projects upwardly from the upper plate 225 to limit Vthe rotary movement of the disc and of thelatchmember II'I.

Referring particularly to Figs. 5, 6 and '1 of the drawings, the latch-member II1 is provided with a vertically disposed slot 219 into which the projection I I9 of the tripping toggle-link |01 extends. rihe projection II5 has a latching shoulder 23| which normally rests against the periphery of the latch-member to restrain the tripping toggle in its slightly underset holding position. At the point of latching engagement of the shoulder 28| with the latch-member, the slot 219 has straight parallel sides and is disposed at a slight angle relative to the projection H9 as shown in Fig. 6. At the point. where the projection I I9 extends into the slot 219, the sides of the slot are flared as shown in Fig; '1 to permit unlatching rotation of the latch-member.

The operation of the trip-device and time-delay device is described as follows: Upon the occurrence of an overload-current in any pole of the breaker below a predetermined value, .for instance, below 100070 of normal rated current, the armature 29| of the affected pole is attracted by the xed magnetic core-member and pole-pieces. If the overload occurs in one of the outer poles of the breaker, the armature operates through the projection 2|1 (Fig. 3) to actuate the yoke or trip-bar I9I and move the link |91 toward the left. It the overload occurs in' the center pole, the armature engages the formed over-end |99 of the link |91 to move the link'toward the left. Leftward movement of the link i9-1 through the pin 249 and spring 251 rotates the ratchetwheel 223 counterclockwise (Fig. 3) under the control of the oscillator 259 without substantially increasing the tension of the spring 251. .After the mechanism has operated a predetermined distance, the pin 249 engages the wall of the recess 213 (Fig. 4) in the disc 21| and rotates the disc 21|, the rod 269 and the latch I I1 coun-. terclockwise until arrested by the l.wall of thev recess 215 striking the stop-stud 211;"7The movement of the disc 21| and the latch-member II1 after the engagement of the pin 249 with the disc is suflcient to align the straight portion of the slot 219 (Fig. 6) in the latch-member with the latching shoulder 25| on the projection l I9 thereby permitting collapse of the tripping toggle "l1-|09 (Figs. 1 and '2) and opening" of the contacts in the manner previously described.

The ratchet-wheel 223 is provided with a ilat surface 283 the one end of which, during a tripping operation, passes the lower arm 255 (Fig. 3) of the oscillator, whereupon the pull of the magnet is unrestrained and instantaneously moves the pin 249 the remaining distance to trip the breaker. By moving the oscillator relative to the ratchet-wheel so that a greater or lesser number of teeth is required to pass the oscillator bveacarrear fore the wheel escapes from the oscillator, a longer or shorter time delay may be effected.

As soon as the current is interrupted and the trip magnet is deenergized, the spring 293 acts to restore the armature 29| of the affected pole to its unattracted position. The yoke ISI, link I 91 and the time-delay device are restored to their unoperated positions by means of springs 282 (Figs. 2 and 3) having one end attached to the lower ends of the legs |89 of the yoke I9I and having their other ends attached to spring-studs 254 proiecting from the sides of the housing |8I.

Upon the occurrence of an overload current above 1000% of normal rated current or a short circuit, the armature 20| of the aiected pole operates to instantaneously move the link |91 and pin 249 toward the left and rotate the latch ||1 independently of the ratchet wheel 223 to instantaneously trip the breaker. In this case the force applied to the pin 249 by the armature is suilcient to flex the spring 251 without actuating the ratchet wheel 223, the pin 249 moving toward the left in the slot 25| in the ratchet wheel. As soon as the current is interrupted and the trip magnet is deenergized, the spring 203 restores the armature of the affected pole to its unattracted position and the springs 282 restore the yoke |9I and the link |91 to their normal positions.

The provision of the mechanical escapement time-delay device connected to the tripping yoke makes the trip-device shockproof since the yoke |9| (Fig, 2) is restrained against operation in response to shocks and jarring forces due to the inertia of the ratchet-wheel 223 and the oscillator 259. Undesirable tripping operation of the latch |I1 in response to shocks transmitted to the trip-device in a horizontal direction through the supporting structure and |8I and also through the supporting structure |1-229 to the time-delay device, is thereby prevented.

As was previously set forth, the latch-member ||1 is moved axially upwardly by means of the shunt trip-device |38 to release the tripping toggle lOl-|99 to thereby cause collapse of the operating linkage and opening of the contacts. The shunt trip-device comprises a movable coremember 285 of magnetic material and an energizing winding 281. The movable core-member 285 is secured to a reduced portion of the rod 259 by means of a pin 285 and is adapted to lift the rod upon energization of the winding 281. The movable core-member is disposed for vertical movement in a tube 239 of non-magnetic material, the ends of which are seated in counterbores in the upper and lower legs of the U- shaped frame 229. The winding 281 is Wound on a tube 29| of insulating material surrounding the tube 239 and is insulated from the legs of the bracket 229 by means of insulating plates 293. Disposed in the tube 289 above the movable core-member 295 is a secondary-movable core-member 295 also of magnetic material. The secondary core-member 295 is spaced apart from the movable core 285 by means of a spring 291 coiled about the rod 259, and is movable axially relative to the core-member 285 and the rod 269. The spring 291 is seated on top of the movable core 235 and in acounter-bore in the secondary core 295.

The winding 281 is energized from any suitable source (not shown) either automatically or by the closure of a manually operable switch (also not shown) in the energizing circuit. When the coil isenergized, the movable core 295 is attracted upwardly and'thrusts the rod 269 and l the latch-member I I1 upwardly to free the tripping toggle H11-|09 in the manner previously described in connection with the description of the manual tripping of the breaker. The upward movement of the rod 259 and latch ||1 is limited by the disc 21| on the lower end of the rod striking a member 299 secured to the bottom leg of the bracket 229. Upon deenergization of the winding 281, the movable core 285, the secondary core 299, the trip-rod 269 and the latch |11 are al1 restored to their normal unattractedl positions by the force of gravity.

The purpose of the separate secondary coremember 295 and the spring 291 is to absorb the kinetic energy of the movable core 285, the rod 289 and the latch i I1 imparted thereto as a result of shocks or jarring forces, and thus prevent undesirable tripping of the breaker in response to shocks. The only force due to shock that would cause false tripping movement of the movable core 285 and the trip-rod 269 is in a vertical directicn and comes from the supporting structure II, I1 and 225. Any shock in a vertical direction irnparted to the supporting structure will be transmitted to the movable core 235 which results in accelerating the movable core and the trip-rod 299 upwardly in tripping direction. The spring 291 is relatively weak and serves only to provide a desirable air-gap between the two core- members 285 and 295. When the movable core 285 and trip-rod 299 are moved upwardly in response to shock, the secondary core 295 will remain substantially stationary until the movable core strikes it. When this occurs, the secondary core 295 is accelerated upwardly thereby absorbing substantially all of the kinetic energy of the movable core 285. At the same time, the spring 291 was compressed as the movable core 285 approached the secondary core 295, and the energy stored therein reacts to move the secondary core 295 upwardly. The result is that, after the collision of the core-members, the secondary core 295, having a higher rate of acceleration than the movable core 285, will rebound from the upper leg of the bracket 229 and strike the movable core 295, thus providing an additional retarding force which is effective to prevent upward movement of the latch ||1 and tripping of the breaker in response to sudden shocks or jarring forces.

From the foregoing description it will be apparent that there is provided a circuit breaker having a main latch which is movable rotatably by any one of a plurality of overload trip-devices to trip the breaker and movable axially by a separate trip-device to trip the breaker. There is also provided a mechanical time-delay device for delaying tripping of the breaker by any one of the plurality of trip-devices, the time-delay device also serving to prevent rotary tripping operation of the latch in response to shocks. There is also provided means for preventing axial tripping movement of the latch in response to shocks. A further advantage of the inven-` tion lies in the adjustment of the oscillator of the time-'delay device relative to the ratchetwheel to vary the amount of time delay.

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details thereof may be made without departing trom the spirit of the invention.

W e claim as our invention:

l. In a circuit breaker, trip-means operable ll' in ,response to abnormal circuit conditions for effecting operation of said breaker, a time-delail device ,comprising a mechanical escapement mechanism operatively related to said trip-means for at times retarding operation of said tripmeans, said' time-delay device comprising a ro- .able in response to predetermined abnormal circuit conditions to operate said trip member, a time-delay device for retarding tripping operation of said trip member in response to abnormal circuit conditions below said predetermined value, said time-delay device comprising a rotatable member and an oscillator cooperating therewith for retarding rotation of said rotatable member., pivot means for said rotatable member, and an arm mounted on said pivot means for adjusting said oscillator about the periphery of said rotatable member to vary the amount of time delay;

3. In a circuit breaker, a trip-member oper-- able to cause circuit opening operation of said circuit breaker, electroresponsive means for operating said trip-member, a time-delay device for retarding operation of said trip-member in response to. abnormal circuit conditions below a predetermined value,` said time-delay device comprising a rotatable member having teeth about a portion of its periphery and an oscillatorcoop'erating therewith to retard operation of said trip-member, said rotatable member after moving a predetermined distance being released from said oscillator to effect operation of said trip-member, spring means operatively relating said trip-member to said vtime-delay device to permit instantaneous operation of the tripmember in response to abnormal circuit conditionsv above said predetermined value, and a pivoted member supporting said oscillator for circumferential movement about the rotatable member to vary the number of oscillations required of said oscillator to effect trippingr of the breaker.

4. In a multi-pole circuit breaker, a tripmember common to all of said poles and operable to cause automatic opening of said breaker, electroresponsive means for each pole operable upon the occurrence of abnormal circuit conditions in the related pole to operate said tripmember, a single time-delay device for retarding tripping operation of said trip-member in response to abnormal circuit conditions occurring in any pole of the breaker, said time-delay device comprising a rotatable member and an oscillator cooperating with said rotatable member to retard tripping operation of said tripmember, said rotatable member after a predetermined travel moving free of said oscillator to actuate said trip-member, and a member pivoted coaxially with said rotatable member and operable to adjust the oscillator about the periphery of said rotatable member to vary the amount of time delay.

5. In a multi-pole circuit breaker, a tripmember common to all of the poles and operable to cause automatic opening operation of said breaker, electromagnetic means for each pole operable upon the occurrence of abnormal circuit conditions in the related pole to operate said trip-member, a single time-delay device for retarding tripping operation of said trip-member in response to abnormal circuit conditions below a predetermined value occurring in any pole of the breaker, said time-delay device comprising a rotatable member and an oscillator cooperating therewith to retard operation of the tripmember, said rotatable member after a predetermined movement being released from said oscillator to effect operation of said trip-member, a spring connecting the trip-member to said time-delay device to permit instantaneous operation of the tripmember in response to abnormal circuit conditions above said predetermined value occurring in any pole of the breaker, and a lever pivoted for concentric movement about said rotatable member for adjusting said oscillator about the periphery of said rotatable member to vary the amount of time delay.

6. In a circuit breaker, trip-means operable to cause circuit opening operation of said breaker, a Itime-delay device operatively related to said trip-means comprising a rotatable member and an oscillator engaging said rotatable member for retarding rotation of said rotatable member, said rotatable member after moving a predetermined distance being released from said oscillator to effect operation of said trip-means, and a pivoted lever for adjusting the oscillator about the periphery of said rotatable member to vary the distance said rotatable member is required to travel before it is released from said oscillator.

7. In a circuit breaker, trip-means operable to cause circuit opening operation of said operatingl mechanism, a time-delay device related to said trip-means to retard operation of said tripmeans, said time-delay device comprising a rotatable member provided with teeth about a portion only of its periphery and an oscillator engaging said teeth to retard operation of said rotatable member, said rotatable member after moving a predetermined distance being released from said oscillator to effect operation of said trip-means, and a pivot-ed lever for adjusting said oscillator about the periphery of said rotatable member to vary the number of teeth required to pass said oscillator before said rotatable member is released.

8. In a circuit breaker, a trip-member operable to effect opening operation of said breaker, a time-delay device related to said trip-member for retarding operation of said trip-member, said time-delay device comprising a rotatable member having teeth formed about a portion of its periphery and an oscillator cooperating with said teeth .and operable to retard rotation of said rotatable member, means operable in response to abnormal circuit conditions to rotate said rotatable member a distance sufficient t0 cause said member to escape said oscillator after a predetermined time delay to effect operation oi said trip-A member, a pivoted member supporting said oscillator for oscillatory movement, and manual means for moving said pivoted member to selectively position said oscillator about the periphery of said rotatable member to vary the amount of time delay.

9. In a circuit breaker, a trip-member operable to cause circuit opening operation of said breaker, a time-delay device related to said tripmember to retard operation of said trip-member, said time-delay device comprising a rotatable member provided with teeth about a portion of its periphery and an oscillator engaging said teeth to retard operation of said rotatable member, said rotatable member after a predetermined travel being released from said oscillator to effect operation of said trip-member, a casing enclosing said time-delay device, a pivoted lever mounted in said casing for supporting said oscillator, common pivot means for said rotatable member and said lever, and manual means disposed outside of said casing and operable to move said lever to selectively position said oscillator about the periphery of said rotatable member to vary the amount of travel of said rotatable member before said rotatable member is released from said oscillator.

10. In a circuit breaker, trip-means operable to cause circuit opening operation of said breaker, a time-delay device operatively related to said trip-means comprising an oscillator and a rotatable member operatively engaging said oscillator for a portion only of its rotation to be retarded thereby and then rotating free of said oscillator to actuate said trip-means, electroresponsive means for actuating said rotatable member, and a pvoted lever supporting said oscillator and movable to position said oscillator about the periphery of said rotatable member to vary the amount of rotation of said rotatable member before it moves free of said oscillator.

11. In a circuit breaker, trip-means operable to cause circuit opening operation of said breaker,

a time-delay device operatively related to said.

trip-means comprising an oscillator and a rotatable member operatively engaging said oscillator for a portion only of its rotation to be retarded thereby and tlien rotating free of said oscillator to actuate said trip-means, electroresponsive means for actuating said rotatable member, spring means between said electroresponsive means and said rotatable member to permit said electroresponsive means to instantaneously actuate said trip-means independently of said timedelay device, and a pivoted lever supporting said oscillator and movable to position said oscillator oircumferentially about said rotatable member to vary the amount of rotation of said rotatable member before said rotatable member moves free or? said oscillator.

LEON R. LUDWIG.

WILLIAM H. STUELLEIN.

GAYNE D. GAMEL.

EEFXZRENEES CITED The following references are of record in the oi this patent:

UNITED STATES PATENTS .i Number Name Date 1,868,898 Ireland July 12, 1932 2,081,727 Barenyi May 25, 1937 2,439,165 Graves, J'r Apr. 6, 1943 2,459,533 Sandin et al Jan. 1S, 1949 FOREIGN PATENTS Number Country Date 335,015 Germany Mar. 26, 1921

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