US2667548A - Circuit breaker trip control device - Google Patents

Description

Jan. 26, 1954 R. G. PAGE 2,667,543

CIRCUIT BREAKER TRIP CONTROL. DEVICE mea Nov. 9, 195o 12 Fi .L I5 I4 .g I4 19 I8 16g e l 3 5 Y u o X www. I'

7 ol Y* IO 8 l l2, 4 'l H I torne'g.

IZ 1 lnventor T I Re @Pt G'page b Patented Jan. 26, 1954 CIVRGUIT-BREAKER TRIP CONTROL DEVICE '.Robert V(Si. Page; New Britain, Conn., assignor, by

. mesne assignments, .to General Electric-Company, a corporation of New York `Application November 9, 1950, Serial No. 194,758

10 Claims. (01,200-116) My invention relates to circuit breaker trip control devices, and in particular to such :devices which are adapted vto :be shock-resistant.

In circuit :breakers Vof the.typev shown herein,

a movable trip-restraining member is `provided,

which may be :caused to move bylthermaland/or `Vmagnetic means responseto current overloads to Vcause tripping or automatic opening yof the breaker.

It is desirable that movementsoi ,such ,member be unimpeded by Afriction asmuch as possible :in order that accuracy of .calibration may -be mainn tained. At the same time, it is alsodesirable that when the breaker is subjected to :a physical shock, jarring or vibration, the parts of the trip.

2device shall not :be caused to move in such a way as to cause falser tripping.

-It isan object of .thepresent-:i-nvention to provide tripping means for a circuit breakerV which permits tripping by thermaleand/oirmagnetic means but which is not sensitive to physical shock.

It .isa furtherobjcct to provide ysucht,u tripping means which shallbe simple and linexpensive yto 4.mami-facture vand which Ashall be reliable in op eration.

It is `a morespeci-iic object Aof mya'nvention to provide a .current ,responsive circuit breaker latch ,havingmeans responsive ftoshock -to prevent false tripping of the breaker without-:inany way inhibiting normal `overcurrent.operation.

ertia latch and showing themarts'intheir freset position; Fig. -et isa top view of `the tripping mechanism of Fig.. .Bland Figf is thesame view as vshown in Fig..3 except that theparts are illus- .trated in vthe positions assumed after themechanism has .been subjected to, shock.

y Fig. `6 is a. side.:elevational yiewzinnsection fof another modiiication :of n1y:;inventionl utilizing -a reinforced biznetall-ic membe1.aszameans of inir-iin'iizing fault stripping due Ato :shockand Fig.

A'Z illustrates the same viewmith .the in .the

.position assu-med when thenmechanismis tripped.

Figs. -8 10 .ares-side lelevational views of further modiiications utilizing reinforced :bimetallic trip .members with the parts .in the position assumedwhen the brealreris reset and Figs. `9 and l1 are correspondingviews :showing parts of the mechanismrinthe `tripped position.

The vcircuit .breaker-.mechanism 4is conventionally mountedland `rnay.-,accommodate any number of poles. `In this instance, the '.inventionis shown as appliedto la. three.-,pole unit. the base having three chambers .(onlyone shown). in one of which the -mechanismis located-which controls switching members located in each Xof the chambers.

The circuit breaker'operating mechanism may be of any suitable type. For convenience, I have shown the invention used with an operating mechanism similar to thatshownv anddescribed in Patent 2,455,753, issued Decemberl 7, 1948., to iB. E. Getchell.

This operating mechanism shown is of the quick-makefquick-break 'type employing :an overcenter toggle asxmore particularly described lin the above-mentioned patent.

'I'he mechanism has la .switch contact member I hinged at I and actuated manually :inaconventional manner and the circuit -is openedautomat-ically in case of yan overload. 'Ihismochanism is suitably carried by .a frame 3 which is mounted inna housing havingl a base 4'Il-and a `cover 5. y -The stationary switchfcontact .4 is

mounted Von the base-1andconnectedto the :circuit terminal Y The mechanism is provided with a springpressed trip arm 2 which is normally held vvfrom `moving by suitable latch. means to l:be described Yand which is releasable to .cause automatic opening of the Icontacts upon the occurrence :of .predetermined circuit conditions.

Referring to Fig. 1, the tri-p arm .2-is normally restrained from mov-ing in an upward Vdirection vby a restraining latch-mpivoted'at l. The -engagement of tri-p arm-.Ziwi-th the latchf tends to krotate the latch counterclockwise about its lpivot 1 against the bias of a coiled spring v8. The latch 6 is prevented from. rotating -in-this-manner, however, by its engagement with za metal iin `hcarriedby latch locking shaft Ill.

The shaft IIJ is supported forl rotation by two brackets II (only one shown). andvcarriesatone end thereof two toutwardly extending ns l2 and I2.

Extending upwardly from the base 4, adjacent the ns .|2, l2' -is a bracket I3, having an aL- shaped pendulous inertia member I5 mounted for rotation thereon .by means loi' fa pin xor rivet I4, and having two projecting pins lBva-nd i6' and having Aa weight vITI attached at itsfoot vas by soldering.

Also extending upwardly from base '4 `adjacent fins I 2 and l2. is a bimetal member or-other current actuated member I9 carrying la icalibratng :screw 2l] and in circuit with. the switchirmember I and the terminal y.

. Inoperation an excess current traversingzmember IScauses it to deflect tothe rightzas seen in Fig. 1 so thatV the tip of, carlibrating screw 2-0 contacts the upper -n fI2 and rotates shaft I-ll It will be observed that during such norm-alv overload operation, L-shaped member I5 remains inactive and in no way restrains or aids tripping because of a certain amount of lost motion between the member I5 and the ns I2 and I2', i. e., the shaft I0 and fins I2 and I2 are free to rotate within limits between the pins I6 and I6 of the inertia member I5.

On the occurrence of a shock which tends to cause the upper end of member Il) together with calibrating screw 20 to move to the right to contact iin I2, which action if unrestrained, would cause false tripping. L-shaped member I5 and its weight I 1, however, also move to the right when the breaker is subjected to such a shock and this causes pin I 6 to contact fin I2', and tends to rotate shaft In in a counter-clockwise direction, opposing the action of member I9.

If a shock should occur in such a way as to cause pendulous L-shaped member I5 to move to the left as seen in Fig. 1, pin I6 will come in contact with iin I2 and likewise tend to rotate shaft arm I counter-clockwise to restrain tripping.

This is important since the L-shaped member I 5, in swinging due to vibration or shock, may get out of phase with the vibration of thebimetal, and be moving to the left as seen in Fig. l, while the bimetal or some other force tends to rotate shaft arm I0 so as to cause tripping. In such a case, the L-shaped member I will still act to prevent such tripping.

In other words, regardless of which way L- shaped member I5 swings about its pivot III, the engagement of the pins IE, I6', with the ns I2, I2 is such as to exert a force on it in a counterclockwise direction.

In Figs. 3, 4 and 5, I have shown a magnetic trip element used as an inertia latch. In this form, 2| is a U-shaped piece of magnetic material such as soft iron, supported on a resilient mounting strip 22 anchored to the base and arranged so as to embrace bimetal 23. Fin 24 is also made of magnetic material so that when a surge of current passes through bimetal 23, the magnet is energized and the effect of the magnetic field will be to pull n 24 toward magnet 2| to cause tripping.

When this system is subjected to a shock such as would cause the bimetal to move to the right so as to tend to cause tripping, magnet 2l also moves to the right under the effect of the shock as shown in Fig. 5 and prevents iin 24 from moving back, thereby preventing tripping.

The shock-resistance of a circuit breaker embodying my invention may be improved further by means of the special current actuated systems of Figs. 6 to 11.

In Figs. 6, 8 and 10 the parts are shown in the positions assumed in the closed position of the breaker and in Figs. 7, 9 and 11 the same parts are shown in the positions assumed after the breaker has tripped. The parts other than those of the reinforced bimetal members correspond to parts illustrated in Figs. 1 and 2 and the same reference numerals have been used to designate corresponding parts.

In the system of Fig. 6, I provide two bimetal elements 3l, 32 joined together at one end, and xedly supported on the base 4 to form a rigid triangular structure. When subjected to heat,

such as caused by an excess current, both bimetals deiiect as shown in Fig. l to cause tripping. The structure being rigid, it is unlikely to bend except by heat.

In the system of Fig. 8, I employ a, similar triangular structure made up of two members, one of which, 36, is a bimetallic member, and the other of which 3Iis a single metal strip having a highdegree of linear expansion. When this system is subjected to heat it deiiects as shown in Fig. 9, the bimetal 36 deflecting while the metal strip 3l merely becomes slightly longer.

In the system of Figs. 10 and 11, I provide a bimetal member 40, having connected in parallel therewith, a reinforcing bimetal 4I. When subjected to heat, both bimetals deflect as shown in Fig. 11.

It will be seen that in all of the systems of Figs. 6 and 7, 8 and 9, and l0 and i1, I have provided bimetal systems which, although they will deflect when subjected to heat, such as that caused by a current passing therethrough, are extremely rigid and not subject to deiiection by shock or vibration.

It will be seen that I have provided a trip device for circuit breakers which is highly shockresistant and yet simple and inexpensive in construction.

While I have described only certain preferred embodiment of my invention by Way of illustration, many modifications will occur to those skilled in the art, and I therefore wish to have it understood that I intend in the appended claims to cover all such modifications as fall within the true spirit and scope of my invention.

I claim:

1. In a circuit breaker having cooperating switch contacts, a trip member movable to effect automatic separation of said contacts, latching means normally engaging said trip member to restrain its movement and including at least one movable member, means movable in response to the current traversing said contacts to engage said movable member and move it to a latch-releasing position, said current responsive means being similarly movable in response to a shock force in one direction, and an unbalanced inertia member having a lost motion connection with said movable member and movable in response to such shock force to engage said movable member and oppose its movement to latch-releasing position.

2. In a circuit breaker having cooperating switch contacts, a trip member movable to effect automatic separation of said contacts, latching means normally engaging said trip member to restrain its movement and including at least one movable member, means movable in response to the current traversing said contacts to engage said movable member and move it to a latch-releasing position, said current responsive means being similarly movable in response to a shock force in one direction, and an unbalanced inertia member having a lost motion connection with said movable member and movable in one direction in response to such shock force and also in the opposite direction to engage said movable member and oppose its movement to latch-releasing position.

3. In a circuit breaker having cooperating switch contacts, a trip member movable to effect automatic separation of said contacts, latching means normally engaging said trip member to restrainits movement and including at least one movable member,4 means movable in response to the current traversing said contacts to engage said movable member and move it to a latchreleasing position, said current responsive means being similarly movable in response to a shock force in one direction, and a pendulum swingable in response to such shock force to engage said movable member and oppose its movement to latch-releasing position.

4. In a circuit breaker having cooperating switch contacts, a trip member movable to effect automatic separation of said contacts, latching means normally engaging said trip member to restrain its movement and including a rotatable member, means movable in response to the current traversing said contacts to engage said rotatable member and move it to a latch-releasing position, said current responsive means being similarly movable in response to a shock force in one direction, and a pendulum having a lost motion connection with said rotatable member and swingable in either direction to engage said rotatable member and oppose its movement to latch-releasing position, said pendulum being swingable in one direction in response to shock force in said one direction.

5. In a circuit breaker having cooperating switch contacts, a trip member movable to effect automatic separation of said contacts, latching means normally engaging said trip member to restrain its movement and including a rotatable member having oppositely extending radial arms, means movable in response to the current traversing said contacts to engage said rotatable member and move it to a latch-releasing position, said current responsive means being similarly movable in response to a shock force in one direction, and a swingable pendulum having a lost motion connection with said rotatable member, said lost motion connection comprising projections on said pendulum engageable with opposite sides of said opposite radial arms whereby one of said projections engages one of said arms upon movement of said pendulum in either direction thereby to oppose movement of said rotatable member to latch-releasing` position.

6. In a circuit breaker having cooperating switch contacts, a trip member movable to effect automatic separation of said contacts, a releasable latch member normally engaging said trip member to restrain its movement and biased to releasing position, a movable locking member normally engaging said latch member to retain it in latching position, means movable in response to the current traversing said contacts to engage said locking member and move it to release said latch member, said current responsive means being similarly movable in response to a shock force in one direction, and an unbalanced inertia member movable in response to such shock force to engage said movable member and oppose its movement to latch-releasing position.

'7. In a circuit breaker having cooperating switch contacts, a trip member movable to effect automatic separation of said contacts, a releasable latch member normally engaging said trip member to restrain its movement and biased to releasing position, a rotatable locking member normally engaging said latch member to retain it in latching position, means movable in response to the current traversing said contacts to engage said locking member and move it to release said latch member, said current responsive means being similarly movable in response to a shock force in one direction, and an unbalanced inertia member having a lost motion connection with said rotatable locking member and movable in one direction in response to such force and also in the opposite direction to engage said locking member and oppose its movement to latch-releasing position.

8. In a circuit breaker having cooperating switch contacts, a trip member movable to effect automatic separation of said contacts, a releasable latch member normally engaging said trip member to restrain its movement and biased to releasing position, a movable locking member normally engaging said latch member to retain it in latching position, means movable in response to current traversing said contacts to engage said locking member and move it to release said latch member, said current responsive means being similarly movable in response to a shock force in one direction, and a swingable pendulum normally spaced from said locking member and movable in response to such shock force to engage said locking member and oppose its movement to latch-releasing position.

9. In a circuit breaker having cooperating switch contacts, a trip member movable to effect automatic separation of said contacts, a releasable latch member normally engaging said trip member to restrain its movement and biased to releasing position, a rotatable locking member normally engaging said latch member to retain i-t in latching position and including a pair of oppositely directed radial arms, means movable in response to current traversing said contacts to engage said locking member and move it to release said latch member, and a swingable pendulum having a lost motion connection with said rotatable locking member and movable in either direction to engage said locking member and oppose its movement to latch-releasing position, said lost motion connection comprising-projections on said pendulum normally spaced from and engageable with opposite sides of said oppositely directed radial arms.

10. In a circuit breaker having cooperating switch contacts, a trip member movable to effect automatic separation of Said contacts, latching means normally engaging said trip member to restrain its movement and including at least one movable member, a thermally responsive member deformable in response to the current traversing said contacts to engage said movable member and move it to a latch-releasing position, said thermally responsive member being similarly deformable in response to a shock force in one direction, and a U-shaped magnetizable member resiliently mounted to embrace said thermally responsive member and disposed for movement in response to such shock force to a position of engagement with said movable member to oppose movement of said movable member to latch-releasing position.

ROBERT G. PAGE.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 570,212 Wurts Oct. 2'7, 1896 2,353,406 Kouyoumjian July 11, 1944 2,438,373 Oppel Mar. 23, 1948 2,534,906 Grssinger Dec. 19, 1950

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