US2952758A - Thermal circuit breaker - Google Patents

Thermal circuit breaker Download PDF

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Publication number
US2952758A
US2952758A US804640A US80464059A US2952758A US 2952758 A US2952758 A US 2952758A US 804640 A US804640 A US 804640A US 80464059 A US80464059 A US 80464059A US 2952758 A US2952758 A US 2952758A
Authority
US
United States
Prior art keywords
spring
rocking member
circuit breaker
contact
housing
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US804640A
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English (en)
Inventor
Ellenberger Jakob
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ellenberger and Poensgen GmbH
Original Assignee
Ellenberger and Poensgen GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ellenberger and Poensgen GmbH filed Critical Ellenberger and Poensgen GmbH
Priority claimed from DEE18401A external-priority patent/DE1114911B/de
Application granted granted Critical
Publication of US2952758A publication Critical patent/US2952758A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H73/00—Protective overload circuit-breaking switches in which excess current opens the contacts by automatic release of mechanical energy stored by previous operation of a hand reset mechanism
    • H01H73/22—Protective overload circuit-breaking switches in which excess current opens the contacts by automatic release of mechanical energy stored by previous operation of a hand reset mechanism having electrothermal release and no other automatic release
    • H01H73/30—Protective overload circuit-breaking switches in which excess current opens the contacts by automatic release of mechanical energy stored by previous operation of a hand reset mechanism having electrothermal release and no other automatic release reset by push-button, pull-knob or slide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10—Operating or release mechanisms
    • H01H71/12—Automatic release mechanisms with or without manual release
    • H01H71/14—Electrothermal mechanisms
    • H01H71/16—Electrothermal mechanisms with bimetal element
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H71/00—Details of the protective switches or relays covered by groups H01H73/00 - H01H83/00
    • H01H71/10—Operating or release mechanisms
    • H01H71/12—Automatic release mechanisms with or without manual release
    • H01H71/44—Automatic release mechanisms with or without manual release having means for introducing a predetermined time delay
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00—Discharge tubes and lamps
    • H01J2893/0072—Disassembly or repair of discharge tubes
    • H01J2893/0073—Discharge tubes with liquid poolcathodes; constructional details
    • H01J2893/0074—Cathodic cups; Screens; Reflectors; Filters; Windows; Protection against mercury deposition; Returning condensed electrode material to the cathodic cup; Liquid electrode level control
    • H01J2893/0075—Cathodic cups
    • H01J2893/0078—Mounting cathodic cups in the discharge tube

Definitions

  • the present invention relates to a novel design of a thermal circuit breaker of the type comprising a contact spring with a contact on its free end and a bimetallic spring which is adapted to pivot the contact spring into the connecting or disconnecting position by means of a rocking member which is pro-vided with a pair of opposite V-shaped recesses.
  • a thermal circuit breaker of the type comprising a contact spring with a contact on its free end and a bimetallic spring which is adapted to pivot the contact spring into the connecting or disconnecting position by means of a rocking member which is pro-vided with a pair of opposite V-shaped recesses.
  • the contacts are opened and closed rapidly in order to prevent them rom sparking.
  • the contact spring had three tongues.
  • the central tongue of this spring consisted of two parts, the inner ends of which engaged in V-shaped recesses in a rocking member, while each of the two outer tongues was bent to have an S-shape whereby a snap action was produced.
  • the three-tongued spring On its free end, the three-tongued spring had a contact which, in the connecting position, was in engagement with the contact of a birnetallic. spring.
  • the bimetallic spring was heated and bent by the action of a heating coil so that the contact of the three-tongued spring was disengaged.
  • the longer part of the central tongue was taken along so that it formed an acute angle relative to the shorter part of the central tongue.
  • thermal circuit breaker of the above-mentioned type operating in the nature of a snap-action switch, which may be very easily manufactured and assembled, and in which the lmovable parts, that is, the contact spring and the bimetallic spring carry out only relatively small movements so that they will not suffer from fatigue failures and the life of the switch will be lengthened, and in which the contacts will be separated suddenly and properly and may be closed with a delay of such movement.
  • a suitable delay of the closing movement is according to the invention to be attained especially if the contacts have automatically opened due to an excess current or heating from the outside and should again close automatically after a certain length of time.
  • a further object of the invention is to provide a thermal circuit breaker of a design which may also be applied to a three-phase alternating current and which is designed to separate all three phases if an excess current occurs in any one of these phases.
  • the invention provides that the rocking member with the V-shaped recesses therein is mounted on the opposite ends of the contact spring and the birnetallic spring and that the contact spring engages in the respective V.shaped recess in the rocking member under an initial tension. Since the rocking member lies between the ends of the two mentioned springs, the end of the bimetallic spring forms the pivot point of the rocking member.
  • rocking member can pivot freely and since there is no fixed pivot point, a certain delay in the pivoting movement may be provided by preventing the movement of the rocking member to its tipping point from automatically resulting in an immediate tipping thereof to the other end position. This may be attained since it is possible to maintain a straight-line connection between the two springs during a certain pivoting range.
  • the actual tipping of the rocking member will result in a pivoting of the contact spring in one or the other direction, that is, from the closed position to the Open position of the contacts or vice versa. It is then immaterial whether the bimetallic spring will be bent by being heated Iindirectly by its heating coil which is energized by an excess current or whether the circuit breaker is acted upon directly by a heat source, for example, the windings of a motor.
  • the rocking member according to the invention is preferably made of a suitable insulating material in order to insulate the contact spring from the bimetallic spring.
  • at least the V-shaped recess into which the bimetallic spring engages is preferably provided with a metallic lining in order to prevent undue wear on the rocking member itself.
  • This metallic lining is also of importance insofar as it will protect the insulating ma ⁇ the bimetallic spring has to produce in order to operate the circuit breaker
  • the rocking member ma accordingv to another feature of the invention be connected to or provided with a brake element which is adapted to engage with a cooperating brake surface at least during the pivoting movement of the rocking member in one direction.
  • the brake element may for this purpose be provided with a Ibrake arm which is pivotable against the action of a spring only in one direction of the rocking movement of the rocking member. Consequently, the brake arm will yield resiliently only during the movement in one direction, for example, during the disconn necting movement, but not during the movement for closing the contacts in which an additional friction is thus produced.
  • This friction requires that the bimetallic spring has to cool off considerably and produce a greater force in the direction toward the cold side until the tipping point is reached.
  • the friction factor is then determined by the length of the friction surface, which will thus also determine the length of time of the return movement of the switch. Thus, if the length of the friction surface is increased, it will take a correspondingly greater length of time until the movement of the bimetallic spring will bring the rocking member to the tipping point.
  • the mentioned brake surface which is to be engaged by the brake arm on the rocking member is provided within the housing of the circuit breaker and preferably on a part of the housing, although it may, of course, also be provided on the cover of the housing.
  • the invention further provides the same or the part of the housing carrying the same to be adjustable relative to the brake arm on the rocking member.
  • the circuit breaker according to the invention may also be used as a three-pole relay for three-phase induction motors and similar apparatus by mounting three of these circuit breakers in a row behind each other within a common housing and by connecting them by means of a common rocking member.
  • Such a circuit breaker requires only a single locking device which is adapted to engage with one of the three contact springs to arrest all of these springs in the open position, and which is releasable by a single release key. lf the circuit breaker is intended to operate only thermally, it is advisable to mount the same in a manner so as to permit the heat,
  • the housing of the circuit breaker is preferably provided at one side with a perforated cover plate through which the outside heat may enter into the housing.
  • Figure 2 shows a cross section taken along line II-II of Figure 1;
  • Figure 3 shows a perspective view of the rocker member according to the invention with the brake element thereon;
  • Figure 4 shows a View of the circuit breaker according to Figure 1, With its contacts in the open position;
  • Figure 5 shows a perspective view of the lower side of the housing of the circuit breaker
  • Figure 6 shows a perspective view of the upper side of the housing; while Figure 7 shows a diagrammatic perspective view of a circuit breaker mechanism according to the invention used as a three-pole relay.
  • the circuit breaker according to the invention is mounted within a housing 1 which is provided with a cover plate 2 with a plurality of apertures 3 therein for conducting the heat developed within the housing to the outside without, however, permitting any heat to pass from the outside into the housing, which is of importance if the circuit breaker is supposed to work purely thermally.
  • a contact spring 5, the free end 6 of which carries a contact 7, is mounted in housing 1 at 4.
  • Contact 7 cooperates with a contact 8 on a second contact spring 9 which is mounted in the housing at 10 and adapted to be adjusted to have a certain initial tension by means of a screw 11.
  • Housing 1 -further contains a bimetallic spring 13 which is mounted at 12 and surrounded by a heating coil 14.
  • This heating coil 14, as well as the contact spring 5, is conductively connected at @l to a terminal screw 15 to which a separate circuit may be connected.
  • the free end 16 of the bimetallic spring 13 carries a screw 17 through which the heating coil 14 is conductively connected to the bimetallic spring which, in turn, is connected at its mounting point 12 to a terminal screw 1S.
  • a third terminal screw 19 isV mounted on housing 1 adjacent to screw 1S. This terminal screw 19 is connected to the second contact spring 9 and secures the same at 11i to the housing ll.
  • a rocking member 20 which preferably consists of a plastic material and has a substantially double-trapezoidal cross section, as shown particularly in Figure 3, is interposed between the free ends 6 and 16 of contact spring 5 and bimetallic spring 13 and provided with V- shaped recesses 21 and 22 in its opposite end surfaces which are associated with springs 5 and 13.
  • Recess 22 is reinforced by a lining of sheet metal 23 in order to protect the rocking AInember 20 of plastic from being unduly worn when it is heated by the bimetallic spring 13.
  • Housing 1 further carries at 25 an arresting spring 24 which is disposed above the contact spring S and the hooked end portion 26 of which is adapted to pass through an aperture 27 in spring 5 and to engage with the lower side of this spring when the latter is bent to the position as shown in Figure 4.
  • a release key 28 is slidably mounted in housing 1 and adapted to be depressed against the action of a spring 29.
  • the rocking member 20 ⁇ forms at one side a brake part 30 comprising a brake arm 31 which is adapted to be pivoted upwardly against the action of a spring 32 and to engage with a brake surface 33 on housing 1, as illustrated in Figures 1 and 4.
  • this brake surface 33 may be enlarged or reduced by providing it on a slide member 34 which may be adjusted toward the right or left, as viewed in Figure 1, by means of a screw spindle 35 which is mounted in housing 1 at 36.
  • a screw spindle 35 which is mounted in housing 1 at 36.
  • the cover plate 2 is preferably secured to housing 1 by hollow rivets 38 through which suitable screws may be inserted to mount the switch on a wall surface or on the apparatus which it is designed to protect or control.
  • the bimetallic spring 13 will likewise cool oi after contacts 7 and 8 are separated, such cooling will have no effect since contact spring 5 will be held arrested inthe bent position by spring 214. If the release key 28 is then depressed to disengage the arresting spring 24 from Contact spring 5, the latter will swing back to the contact-closing position, and such movement will proceed rapidly because of the cooperation of the spring tension of contact spring 5 4with the spring tension of bimetallic spring 13 through rocking member 20.
  • Figure 7 illustrates a modification of the circuit breaker according to the invention which is designed to form a three-pole relay, for example, for a three-phase induction motor. It will be seen that all of the elements contained in the circuit breaker according to Figures 1 to 6 are provided three times, except the housing 1 (not shown) with its cover 2 and the rocking member 20 with the brake part 30 and brake surface 33, and the arresting spring 24 with its release key 28.
  • the individual contact springs 5 and 9 and the parts connected thereto, as well as the bimetallic springs 13 are disposed behind each other and connected by a single rocking member 20. Since there is only one arresting spring 24 provided, only one of the contact springs 5 has to have an aperture 27 for receiving the arresting spring. Since the switch according to Figure 7 in eifect forms three switches according to Figures 1 to 4 behind each other, rocking member 20 is also approximately three times as long as that shown in Figures l to 4.
  • the rocking member 20 may be lslipped from ⁇ one side or the other between the ends 6 and 16 of springs 5 and 13. This facilitates the installation of the switch considerably especially if suitable provision is made that the rocking member 20 may be inserted from the open side of the housing 1, as shown in Figure 5. ln that case, the brake part 30 would be shaped inversely to that shown in Figure 3 and mounted at the end of rocking member 20 ⁇ opposite to that on which it is mounted in Figure 3, so that it will face toward the cover plate 2 of the housing on which the brake surface 33 will then be provided either rigidly or adjustably.
  • the principal advantage ⁇ of the present invention consists in the fact that the rocking member 20 as distinguished from previous circuit breakers with snap contacts does not have a fixed point of location, so that very long lreturn periods yare attainable.
  • the invention affords the additional advantage that the switch operation may be delayed due to the fact that the bimetallic spring has to accumulate a greater force until it can swing lto the position in which the tipping point of the rocking member will be reached, and that the sudden tipping of the rocking member produces a pivoting of the end 6 of contact spring 5 and Athus either a sudden separation or closing of contacts 7 and 8.
  • the contact spring of the circuit breaker according to the invention is moved from one to the other position by the intermediate action of a rocking member which pivots about the free end '16 of the bimetal-lic spring 13.
  • a thermal circuit breaker comprising a contact spring mounted at one end and bent at its opposite end into a U-shaped conguration, said contact spring carrying a contact on the free of the U, a second contact adapted to be engaged by said first contact, a normally lsubstantially straight bimetallic spring mounted at one end, Iand a rocking member having a pair of opposite V-shaped recesses therein interposed between and receiving, respectively, the free end of said free leg of said contact spring and the free end of said bimetallic spring, said rocking mem-ber being :adapted to be freely movable on said free ends Within said recesses, said contact spring engaging into one of said recesses under an initial tension, said bimetallic spring when heated being adapted to bend and through said rocking member to swing said contact spring and the contact thereon to a connecting and disconnecting position relative to said second contact.
  • a circuit breaker as deiined in claim l wherein said rocking member consists of insulating material, :and further comprising a metal lining within at least one of said V-shaped recesses.
  • a circuit breaker as defined in claim l further comprising a brake member connected to said rocking member, and a member having a brake surf-ace thereon, said brake member being adapted to engage said brake surface at least in one direction of the reciprocating movement of said rocking member.
  • a circuit breaker as defined in claim 3, wherein said brake member comprises a supporting member mounted on said rocking member, a Ibrake arm pivotally mounted on said supporting member, and a spring ⁇ acting upon said brake arm, said brake arm being adapted to be pivoted in one direction of the reciprocating movement of said rocking member against the action of said spring.
  • a circuit breaker as defined in claim 1 further comprising means for arresting said contact spring in the open position of said contacts, and means for releasing said arresting device from said spring engaging position.
  • a 'circuit breaker comprising a housing, three contact springs, each mounted at one end Within said ho-using and in a spaced relation behind each other, each of said contact springs being bent at ⁇ its opposite end into a U-shaped configuration, said contact spring carrying a contact on the free leg of the U, second contacts mounted Within said housing, each adapted to cooperate with one of said first contacts, three normally substantially straight rbirnetal-lic springs, each mounted at one end within said housing, a common rocking member having a pair of opposite V-shaped recesses therein interposed between and receiving, respectively, the free ends of said lfree legs or said contact springs and the free ends of said -bimetallic springs, said rocking member being adapted to be lfreely movable on said free ends within said recesses, said contact .springs engaging under an initial tension into one of said recesses, each of said bimetallic springs when heated being adapted to bend and through said conm-on rocking member to swing said Contact lsprings.

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  • Thermally Actuated Switches (AREA)
  • Breakers (AREA)
US804640A 1958-04-23 1959-04-07 Thermal circuit breaker Expired - Lifetime US2952758A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DEE15754A DE1083413B (de) 1958-04-23 1958-04-23 Thermischer UEberstromausloeser
DEE18401A DE1114911B (de) 1959-10-24 1959-10-24 Thermischer UEberstromausloeser

Publications (1)

Publication Number Publication Date
US2952758A true US2952758A (en) 1960-09-13

Family

ID=25972925

Family Applications (1)

Application Number Title Priority Date Filing Date
US804640A Expired - Lifetime US2952758A (en) 1958-04-23 1959-04-07 Thermal circuit breaker

Country Status (5)

Country Link
US (1) US2952758A (da)
DE (1) DE1083413B (da)
DK (1) DK105932C (da)
FR (1) FR1221454A (da)
GB (2) GB860861A (da)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3005075A (en) * 1959-10-24 1961-10-17 Ellenberger & Poensgen Polyphase motor protecting switch
US3022403A (en) * 1960-05-02 1962-02-20 Monitor Controller Division Of Thermally controlled switch
US3265831A (en) * 1962-06-21 1966-08-09 Westinghouse Electric Corp Thermally responsive electrical control device
US3358099A (en) * 1964-12-30 1967-12-12 Bellomayre Michel De Bimetallic-strip and rockable-spring actuated snap-acting switch device
US3743992A (en) * 1972-08-04 1973-07-03 Westinghouse Electric Corp Thermally responsive electrical control device for polyphase currents

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2068374A (en) * 1934-05-26 1937-01-19 Trumbull Electric Mfg Co Thermostatic switch
US2313341A (en) * 1940-02-09 1943-03-09 Honeywell Regulator Co Snap action switch
US2695524A (en) * 1951-01-05 1954-11-30 Honeywell Regulator Co Alternate action snap mechanism
US2872548A (en) * 1955-12-01 1959-02-03 Fed Pacific Electric Co Motor starters

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2505689A (en) * 1945-03-05 1950-04-25 Jefferson Electric Co Circuit breaker or overload control
GB749305A (en) * 1952-03-24 1956-05-23 Sidney Geoffrey Young Improvements relating to snap-action electric switches

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2068374A (en) * 1934-05-26 1937-01-19 Trumbull Electric Mfg Co Thermostatic switch
US2313341A (en) * 1940-02-09 1943-03-09 Honeywell Regulator Co Snap action switch
US2695524A (en) * 1951-01-05 1954-11-30 Honeywell Regulator Co Alternate action snap mechanism
US2872548A (en) * 1955-12-01 1959-02-03 Fed Pacific Electric Co Motor starters

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3005075A (en) * 1959-10-24 1961-10-17 Ellenberger & Poensgen Polyphase motor protecting switch
US3022403A (en) * 1960-05-02 1962-02-20 Monitor Controller Division Of Thermally controlled switch
US3265831A (en) * 1962-06-21 1966-08-09 Westinghouse Electric Corp Thermally responsive electrical control device
US3358099A (en) * 1964-12-30 1967-12-12 Bellomayre Michel De Bimetallic-strip and rockable-spring actuated snap-acting switch device
US3743992A (en) * 1972-08-04 1973-07-03 Westinghouse Electric Corp Thermally responsive electrical control device for polyphase currents

Also Published As

Publication number Publication date
GB860861A (en) 1961-02-15
DK105932C (da) 1966-11-28
FR1221454A (fr) 1960-06-02
DE1083413B (de) 1960-06-15
GB898533A (en) 1962-06-14

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