US1960402A

US1960402A - Switch and circuit breaker

Info

Publication number: US1960402A
Application number: US567796A
Authority: US
Inventors: Kurt W Wilckens
Original assignee: Heinemann Electric Co
Current assignee: Heinemann Electric Co
Priority date: 1931-10-09
Filing date: 1931-10-09
Publication date: 1934-05-29
Anticipated expiration: 1951-05-29

Description

May 29, 1934. K. w. wlLcKENs swITcH AND CIRCUIT BREAKER Filed 06's. 9, 1931 2 Sheets-5116?l May 29 1934- -K. w. AwlLczKENs' swITcH Ami CIRCUIT BREAKER F'iledvoot. 9, 1951 2 sheets-sne:

enemies any aa, reale ser Lgtiiit SWITCH AND GERCUIT BREAKER Application Getober 9, 1931, Seriai No. 567,796

11 Claims..

y My invention is an improved switch and circuit breaker which will withstand a slight overload, of, say, 106%, but will break the circuit after a desired interval upon the maintenance of a slightly greater overload, of, say, 125%, and will break the circuit instantly upon the occurrence of a heavy overload, of', say, 500%; the percentages given being, however, merely illustrative. My improvements are preferably embodied in a l@ switch and circuit breaker of a type having a movable switch member normally biased to open position and retained in closed position by a toggle or similar releasable means which is operable by tripping means actuated electro-magnetically 15 and thermostatically by current iiowing in the circuit controlled by the switch member.

In the preferred, embodiment of my invention,

. a switch' blade normally biased toward open position is held in closed position by a toggle having its joint or knee adjacent to one end of an electro-magnet. A coil of bimetallic thermostatic metal has its axial and fixed adjacent to the opposite end of said electro-magnet. A tripping device. having ,a head interposed between the tog gie joint and the adjacent end of the electro-magnet and a leg extending into the path of the free l, end of the coil, is rocked or lifted by the latter to cause the head to break the toggle joint. The toggle may also be released by the magnetic flux of n the electro-magnet preferably acting through a tripping device such as an armature reciprocable in an axial passage within the solenoid coil comprised in the electro-magnet. The electro-magnet and thermostatic coil. preferably act vindependently1 of one another upon the toggle and the leg of the thermostatic tripping device is preferably oset from the axis of the solenoid coil. The electro-magnet may, however, act through the thermostatic tripping device, either by magnetic attraction of the leg or by having its armature impact against the head of such device. When the electro-magnet and thermostatic coil act through different tripping devices, it is generally desirable that the armature of one pass through an aperture in the head of the other but in some cases the leg of one may be coaxial with and pass through an aperture in the armature of the other.

The characteristic features and advantages of my improvement will further appear from the following description and the accompanying drawings illustrating several embodiments of my invention. i

In the drawings, Fig. 1 is a vertical sectional view of a switch and circuit breaker embodying my improvements; Fig. 2 is a transverse vertical (Cl. 20G- 88) sectional view taken on the line 2-2 of Fig. 1; Fig. 3 is a perspective view of a detached tripping device illustrated in Figs. 1 and 2, Fig. 4 is a. per- A spective view of a detached tripping device which may be substituted for the tripping device shown in Fig. 3; Fig. 5 is a fragmentary view illustrating how a single tripping mechanism may be actuated by both the electro-magnet and thermosta-tic device; Fig. 5a is a perspective View of a modified form of detached tripping device which may be substituted for the 'tripping device shown in Fig.. 5; Fig. 6 is a vertical sectional view of a switch and circuit breaker having a modified form of my improvements applied thereto; Fig. 7 is a transverse vertical sectional view on the line 6-6 of 7@ Fig. 5; Fig. 81s a perspective view of the modiiied form of detached tripping device shown in Figs. .6 and 7; Fig. 9 is a perspective view of modified form of tripping device which may be s bstituted for the device shown in Fig. 8; Fig. 16 is a frag- 75 mentary view showing a further modification of the tripping mechanism in the switch and circuit breaker of Fig. 6; Fig. 11 is a transverse sectional view through the tripping mechanism of Fig. 10; Fig. 12 is a detached plan view of .a split washer 80 used in the constructions illustrated in Figs. 10 and 11; and Fig. 13 is a front elevation of a switch box having a series of switch andv circuit breakers vassembled therein and operable together.

.asr illustrated in the drawings, my improve- `ments are applied to a switch and circuit breaker having a base 1 of insulating material which has fixed thereto a terminal contact 2, connected with one side-of the circuit, and adapted for coaction with a spring switch blade 3, normally biased to open position by having its end 3 bent around a bearing 4. A trough-like carrier 5 is pivoted onthe bearing 4 and the switch blade 3 is engaged-between the bottom of this carrier and a pintle 6 on which is journalled a toggle leg 'l pro- 95 vided with the elastic stop 8. `A second toggle leg 9 is pivotally connected with the leg 'I by the pintle 10 and is also pivotally connected with the segmental handle 11 having a peripheral boss 12 containing an aperture 13. The segmental handle may project through an opening 14 in the cover of a casing l5, but closes such opening in either position of the switch. The' toggle leg 9 has a depending foot 9', the lower end of which/projects 105 on the casing 15; lsuch lugs also having xed 110 thereto arms 18 in which is journalled the axle 19 of the segmental handle l1.

In the form of the invention illustrated in Figs. 1 to 3 inclusive, a non-magnetic tube 20, depending from the bracket 16, has wound thereon a solenoid coil 21, disposed between insulating washers 22, and having one of its ends 21' connected through the terminal 23vwith the switch blade 3.

'I'he other end of the solenoid coil 21 is connected through a flexible conductor 24 with a bimetallic thermostatic member having a coil 25 with its inner or axial end fixed to a conducting and adjustable stud 26 on a conducting bracket 27, to which the other side of the circuit may be connected by a binding post 28. The free end of the bimetallic thermostatic member has a section 29 bent reversely to the coil 25 and covered with a section of insulation 30 which engages the insulated bifurcations 31 of a curved lever 32 fulcrumed on a stud 33 on the bracket 16 and having a section 34 extending across the top of the tube 20 and into the plane of the foot 9' when the switch 3 is in closed position. The elbow or bend of the lever 32 may be reinforced by ribs 32.

Preferably the section 34 of the bell crank lever 32 contains an elongated aperture 35 permitting the passage therethrough of a bronze nose 36 of a magnetically operable armature 37 reciprocable in the tube 20. The length of the nose 36 is sufficient to engage the foot 9' and break the toggle when the armature is moved to its upper limit by the excitation of the coil 21.

If desired, the aperture 35 may be omitted, as shown in Fig. 4 and the nose 36permitted to impact against and rock the member 34, which is thereby moved against the foot 9 to break the toggle. As the bifurcations 31 and section of the lever 32 adjacent thereto, and the head 34 both project in the same direction from the fulcrum formed by the pivot 33, the crank lever 32 is so balanced that the weight of both arms of the lever tends to rock the member 34 toward the electro-magnet and out of the way of the foot 9.

The thermostatic member may be composed of a bimetallic compound strip of invar and steel with the faster expanding metal on the inside of the strip in the coil. Such a strip will not be injuriously eiected by heating up to a temperature of approximately 600.

By positioning the adjustable axis 26 of the thermostatic spring adjacent to the front of the casing 15, adjustments can be conveniently made in the position of the free end of the thermostatic device after the assembly of the mechanism, and the space required for the assembly is minimized.

For ordinary household use, it is desirable that the mechanism hold against 100% overload, trip on a long continued overload of 125%, and trip instantaneously on an overload of 550%. In utilizing a thermostatic coil for operating the breaker between 100% overload and 550% overload, the time required to operate the breaker decreases gradually as the overload increases and approaches 550% overload. As soon as there is 550 overload, the operation of the breaker is effected instantaneously by the electro-magnetic device instead of requiring even the short elapsed time required for the quickest operation by the thermostatic device. This arrangement results in a greater increase in the rapidity of the operation of the breaker when a predetermined critical overload is reached. d

As the position of the thermostatic member has no effect upon the electro-magnetic operationof the device, the mechanism will not be operated by such momentary overloads as are customarily required to start a motor, even though the thermostatic device is partly heated or warm from a previous overload insunicient in itself to cause damage.

It will be understood, however, that when there is an overload for a substantial period of time and exceeding the minimum capacity of the breaker, the thermostatic strip will be suiciently heated to move the member 29 thereof upwardly and inwardly relatively to the fulcrum 26 far enough to rock the lever 32 and move the head 34 against the foot 9', to break the toggle and permit the switch blade 3 to open. If there is a heavy overload, the excitation of the coil 21 instantaneously lifts the armature 37 and projects the nose 36 through the aperture 35 into contact with the foot 9 to break the toggle. Or if the head 34 contains no aperture 35, the impact of the nose 36 against the head 34 will rock such head 34 and cause it to impact against the foot 9 and break the toggle.

As illustrated in Fig. 5, the movable armature 37 may be omitted and the magnetic coil wound around an iron core xed to the magnetizable bracket 16 and forming a pole 37a which is magnetized upon the excitation of the coil 2l and becomes rapidly demagnetized upon the cessation of the current ow. A magnetically permeable pole 37 is provided on the lever 32, so that, when the pole 37a is energized by the excitation of the coil 21, the pole 37 is attracted and the lever 32 is rocked on its fulcrum to cause the member 34 to break the toggle. In this construction the thermostatic means acts on the bifurcated end of the lever 32 as describeddn connection with Figs. l to 4 inclusive.

In the form of the invention illustrated in Figs. 6, 7 and 8, the bracket 16 and washers 22 are provided with slots 38 beyond the periphery of the coil 21 and form a slideway for a trip device cornprising a leg or at rod 39 and a head 40 bent at right angles to the slide 39 and disposed between the top of the tube 20 and the foot 9 when the switch blade 3 is closed. A strip of bimetallic thermostatic metal is bent to form a coil 4l having its faster expanding element on the outside and its axial end xed to the adjustable conducting pin or boss 26 mounted on the conducting bracket 27.

The free end of the coil 41 has connected therewith the conductor 24 and extends through a guide clip 42 depending from the tube 20. The outer end of the bimetallicstrip is covered with insulation and is adapted to engage and lift the leg 39 when the bimetallic strip is heated by prolonged passage of an overload current therethrough.

An armature 37 is reciprocable in the tube 20 under the influence of the solenoid coil 21; the downward movement of the armature preferably being limited by the prongs 20" projecting inwardly from the wall of the tube. The head 40 preferably contains an aperture 43 permitting the passage of the bronze nose' 36 of smaller cross section than the body of the armature 37, as illustrated in Fig. 8, but if desired, this aperture 43 may be omitted as shown in Fig. 9.

It will be understood that when the switch is closed and there is an overload in excess of the minimum and of substantial duration, the coil 41 becomes heated, and since the metals from which il, iS vformed have different coefcients of expansuiliciently excited to elevate the armature 37 with suicient force to cause the nose 36 to break the toggle. When the head is provided with an aperture 43, the nose 36 projects through the aperture and makes direct contact with the foot 9', but, when the form of trip shown in Fig. 9 s used, the impact of the nose 36 on the head 40 lifts the latter into engagement with the foot 9 with sulicient force to break the toggle.

It will be obvious that the form of trip device 39 shown in Fig. 9 may be substituted for the form of trip device 32 shown in Fig. 5 by merely slotting the bracket 16 and washers 22 of the latter and providing a magnetizable foot 39 on the bottom of the leg 39, as indicated in Fig. 5a, the foot 39 projecting into the zone of the pole 37a.

Instead of having the leg of the thermally operated trip device disposed eccentrically to the axis of the solenoid coil, it may be moved through an axial hole in the armature 37" as illustrated in Figs. 10, 11 and 12. In this form of construction, the armature 37, which is movable in the tube 20' under the influence of the coil 21, is drilled longitudinally to provide an axial passage 44, through whichu the leg is freely movable. The downward movement of the armature 37" may be limited by prongs 20" projecting inwardly from the wall of the tube 20', while the downward movement of th'e rod 45 and of the insulated free end of the coil 41 on which the leg rests are limited by a yoke 42 depending from the non-magnetic tube 2o'.

If desired, th`e zone of magnetic flux may be closed or restricted by the insertion of a magnetizable split disc 46 adjacent to but insulated from the coil 21. This permits the armature 3'7" to be positioned closer to the magnetic coil, and fewer turns of wire are required, thereby reducing electrical resistance through the solenoid coil.

It will be understood that when the bimetallic strip 41 is heated by an overload in excess of the minimum and of considerable duration, the end of the strip is moved upwardly and lifts the rod 45, independently of the armature 37', into contact with the foot 9' to break the toggle. When a heavy overload occurs which is desired to check instantly, the excitation of the magnetic coil 21 actuates the armature plunger 37'. The upward movement of the plunger may be transmitted to a collar 45 on the rod 45 to lift the nose of the latter into contact Withthe foot 9', or the collar 45 may be omitted and the plunger permitted to move upwardly into direct contact with the foot 9' to break the toggle.

As illustrated in Fig. 13, a plurality`of my improved switch and circuit breakers may be assembled in a row for controlling polyphase circuits which require the simultaneous operation of all the switches upon the occurrence of an overload in one of the phases. For such purpose, a rod 4'7 is inserted in the apertures 13 of the handles 11 and a rod 48 is substituted for the individual pintles 10 at the joints of the toggles. Consequently upon the occurrence of an abnormal condition on any phase or leg of a polyphase circuit, the switch mechanism for that particular phase or leg is operated by the thermostatic or magnetic tripping means of that particular switch, and the action thereof is transmitted through the rod 48 to the remaining toggles to open the respective switches controlled thereby. When one of the handles 11 is operated to again close one of the switches, the movement is transmitted through the rod 47 to the other handles to simultaneously close all of the switches.

f Having described my invention, I claim:

1. A switch and circuit breaker comprising a movable switch member normally b'ased toward one position, releasable means including toggle members for retaining the switch member in a different position, an' electro-magnet responsive to current in the circuit controlled by the switch member and having one end adjacent to said releasable means, a thermal elementJ re-` sponsive to current in the circuit controlled by said sw`tcl1 member, and trip means operable by said electro-magnet and thermal element and including a fulcrumed lever having a member acting directly on a toggle member aforesaid to prevent the movement of said switch, said thermal element comprising a bimetallic coil having its axial end position adjacent to the end of said electro-magnet remote from said re1eas able means.

2. A switch and circuit breaker comprising a movable switch member normally biased toward one position, releasable means for retaining the switch member in a d'fferent position, an electro-magnet responsive to current in the. circuit controlled by the switch member, a thermal lement responsive to current in the circuiticontrolled by the switch member, and trip `n' 1eans operable by said electro-magnet and thermal element and including a device having a head interposed between one end of said electromagnet and said releasable means and a leg offset from the axis of said electro-magnet and projecting toward the opposite end thereof into the path of said thermal element.

3. A switch and circuit breaker comprising a movable switch member normally biased toward one position, releasable means for retaining the switch member in a different position, an electro-magnet responsive to current in the circuit controlled by the switch member, a thermal element responsive to current in the circuit controlled by the switch member, and trip means operable by said electro-magnet and thermal element and including a dev.' ce attracted-by said electro-magnet and a device having a head interposed betweenone end of said electro-magnet vand said 'releasable means and a leg oiset from the axis of said electro-magnet and projecting toward the opposite end thereof from said head into the path of said thermal element,

said head having an aperture therein for the passage of the other of said devices.

4. A switch and circuit breaker comprising a movable switcn member normally biased toward one position, releasable means including toggle members for retaining the switch member in a different position, an electro-magnet responsive to current in the circuit controlled by said switch member and having one end thereof adjacent to said releasable means, a thermal element responsive to current in the circuit controlled by said switch member and disposed adjacent to the end of said electro-magnet remote from said releasable means,land trip means operable by said electro-magnet and thermal element and including a lever having a fulcrum adjacent to the end of said electro-magnet nearest said releasable means and also having a member acting directly on a toggle member aforesaid to release said switch.

5. A switch and circuit breaker comprising a movable switch member normally biased toward one position, releasable means for retaining the switch member in a different position, an electro-magnet responsive to current in the circuit controlled by the switch member, a thermal element responsive to current in the circuit controlled by the switch member, and trip means operable by said electro-magnet and thermal element and including a device having a head disposed between said electro-magnet and releasable means and a leg offset from the axis of said electro-magnet and slidable parallel to said axis, said thermal element acting directly on said slidable leg.

6. A switch and circuit breaker comprising a movable switch member normally biased toward one position, releasable means for retaining the switch member in a different position, an electro-magnet responsive to current in the circuit controlled by the switch member, a thermal element responsive to current in the circuit controlled by the switch member, and trip means including a device operable by said electro-magnet and a device operable by said thermostatic means, said last named device containing an aperture for the passage of said first named `device.

7. A switch and circuit breaker comprising a movablev switch member normally biased toward one position, releasable means for retaining the switch member in a different position, an electro-magnet responsive to current in the circuit controlled by the switch member, a thermal eleelement responsive to current in the circuit controlled by the switch member, and trip means comprising an armature movable by said electro-magnet along the axis thereof and a lever fulcrumed adjacent to the end of said electromagnet nearest said releasable means and operable by said thermal device and containing an aperture for the passage of said armature.

8. A switch and circuit breaker comprising al movable switch member normally biased toward one position, releasable means for retaining the switch member in a different position, an electro-magnet responsive to current in the'circuit controlled by said switch member and comprising a solenoid coil having an axial passage therethrough, a thermal element responsive to current in the circuit controlled by said switch member, trip means operable by said electromagnet and thermal element, and a split disc adjacent to said solenoid coil, said disc consisting of magnetically permeable metal and restricting the magnetic ilux of said solenoid coil.

9. A switch and circuit breaker comprising a housing containing a movable switch member normally biased toward one position, releasable means for retaining said switch member in a diierent position, a handle adjacent to the front of said housing for operating said releasable means, an electro-magnet responsive to current in the circuit controlled by the switch member, a thermal element responsive to current in the circuit controlled by the switch member, and trip means operable by said electro-magnet and thermal element, said thermal element comprising a bimetallic coil having its axial end adjustably fixed adjacent to the front of said casing at the end of said electro-magnet remote from said releasable means, and said trip means including a device having a head interposed between said electro-magnet and releasable means and a leg on the opposite side of said electromagnet from said coil axis and operable by said thermal element.

10. A switch and circuit breaker comprising a plurality of aligned switch members normally biased toward one position, a toggle connected with each of said switch members, said toggles having the links thereof. pivotally connected by a common rod, electro-magnets respectively responsive to current flowing in the circuits controlled by the respective switch members, thermal elements respectively responsive to current flowing in the circuit controlled by the respective switch members, and trip means operable by the respective electro-magnets and thermal elements to operate all of said toggles and release all of said switches, a handle connected with each of said releasable means and means connecting said handles and actuating all of said switch members upon the operation of one of said handles.

1l. A switch and circuit breaker comprising a movable switch member normally biased toward one position, releasable means including toggle members for retaining the switch member in a different position, an electromagnet having a fixed core with a coil wound thereon, trip means without said coil for operating said toggle, said trip means having a member disposed between said toggle members and said magnet when the switch member is in its second named position, said trip means having a magnetically permeable member adjacent to and operable by a pole of said magnet and a thermal element controlling said trip means.

KURT W. WILCKENS.