US3835275A - Electric power circuit breaker equipped with a latching mechanism wherein restoring forces are provided as a function of switching shaft position - Google Patents

Electric power circuit breaker equipped with a latching mechanism wherein restoring forces are provided as a function of switching shaft position Download PDF

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Publication number
US3835275A
US3835275A US00352202A US35220273A US3835275A US 3835275 A US3835275 A US 3835275A US 00352202 A US00352202 A US 00352202A US 35220273 A US35220273 A US 35220273A US 3835275 A US3835275 A US 3835275A
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United States
Prior art keywords
lever
switching
shaft
spring
latching
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Expired - Lifetime
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US00352202A
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English (en)
Inventor
B Preuss
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Siemens AG
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Siemens AG
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Publication date
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Publication of US3835275A publication Critical patent/US3835275A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H3/00—Mechanisms for operating contacts
    • H01H3/32—Driving mechanisms, i.e. for transmitting driving force to the contacts
    • H01H3/38—Driving mechanisms, i.e. for transmitting driving force to the contacts using spring or other flexible shaft coupling
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H3/00—Mechanisms for operating contacts
    • H01H3/22—Power arrangements internal to the switch for operating the driving mechanism
    • H01H3/30—Power arrangements internal to the switch for operating the driving mechanism using spring motor
    • H01H3/3031—Means for locking the spring in a charged state

Definitions

  • An electric power circuit breaker wherein the latching mechanism as well as other parts which affect the motion of the contacts are returned by restoring forces to their initial position after the breaker is opened.
  • the restoring forces are made ready in dependence on the position of the switching shaft of the breaker and are smaller in the closed position of the switching shaft than in the open position thereof.
  • the invention is suited particularly for low-voltage power circuit breakers for high rated currents wherein the economic configuration of the required springs is of importance.
  • Electric power circuit breakers can be equipped with a latching mechanism which serves in particular for mechanical latching and tripping as well as trip-free releasing the contact members and effecting force transformation when switching the breaker to the closed position. These functions are realized by lever arrangements, clutches, linkages, cams or similar members. These members can occupy two main positions, namely, for the closed position and the open position of the contact members of the circuit breaker.
  • the invention is based on an electric power circuit.
  • the circuit breaker includes a drive mechanism and a latching mechanism containing a switching shaft as well as a latching lever which can be released by a tripping device. Also provided are additional members which can be returned to their initial position by restoring forces after the breaker opens.
  • the restoring forces are made available in dependence on the position of the switching shaft and are smaller in the closed position of the switching shaft than in the open position. This makes it unnecessary for the restoring forces for the latching lever and other members of the latching mechanism to act continuously; instead, these forces are provided only when they are needed.
  • the breaker opening spring required for opening the contacts of the power circuit breaker for instance, can be made weaker than would be possible if the return spring of the latching lever in the latching mechanism were fully effective continuously. A delay in switching open is thereby avoided at the same time.
  • the electric power circuit breaker of the invention includes as a feature contact means switchable between open and closed positions; a latching mechanism for actuating the contact means; and a drive mechanism operatively connected to the latching mechanism for initiating the closing of the contact means by the latching mechanism.
  • the latching mechanism includes a switching shaft operatively connected to the contact means and rotatable between first and second positions corresponding to the open and closed positions of the contacts respectively.
  • Lever means is provided as part of the latching mechanism and is responsive to the drive mechanism for rotating the switching shaft from the first position to the second position.
  • the lever means has a plurality of interacting lever parts movable between an initial position and an end position corresponding respectively to the first and second positions of the switching shaft.
  • a latching lever coacts with the lever means to hold the switching shaft in the second position and tripping means releasably engages the latching lever for releasing the latching lever to withdraw the hold on the lever means.
  • Breaker opening means is operatively connected to the shaft for moving the shaft from the second position to the first position when the latching lever is realeased by the tripping means.
  • the latching mechanism further includes a first resilient means connected to the lever means for directing at least a portion of the interacting parts to the initial position by the action of a restoring force developed in the first resilient means in response to the movement of the switching shaft from the second position to the first position, and a second resilient means engages the latching lever and develops a restoring force for returning the latching lever to the tripping means in response to the movement of the shaft from the second position to the first position whereby the magnitude of the restoring force developed by the second resilient means is less when the shaft is in the second position than when the shaft is in the first position.
  • the invention can, for instance, be realized in a form that in a power circuit breaker which includes a switching lever rigidly connected with the switching shaft, the switching lever serves as an anchor for a return spring.
  • the return spring is tensioned only when the switching shaft with the switching lever arrives in the open position.
  • a latching lever is provided which is pivoted at one end and cooperates at its other end-with a tripping shaft
  • the switching lever may be connected articulately with a bending spring which is braced against a fixed anchor point and a stop of the latching lever and which develops a bending stress that increases as the switching lever moves into the open position.
  • This bending spring may consist of spring wire for example.
  • one of the interacting parts of the lever means is a switching lever rigidly mounted on the switching shaft.
  • the first resilient means can be a first spring having one end anchored to the switching lever, and the second resilient means can be a second spring also anchored to the switching lever.
  • the latching lever be pivotally mounted'at one end thereof and have a bracing stop disposed thereon for bracing the second spring.
  • the tripping means can be a tripping shaft releasably engaging the other end of the latching lever.
  • the latching mechanism can include stationary anchor means for bracing the second spring and the second spring is a bending spring articulately joined to the switching lever and drawn about the bracing stop to increase the bending stress in the bending spring as .the switching lever moves with the switching shaft from the second position to the first position.
  • the bending spring consists of spring wire.
  • the invention can also be used for returning members of the latching mechanism which serve to transmit the closing force. It is, for example, suited for power circuit breakers wherein the force is transmitted to the switching shaft via an idler lever pivotally mounted on the switching shaft and a coupling member arranged between the idler lever and the switching lever.
  • the one lever of an elbow lever system can be articulately connected to the idler lever, and a tension spring can be arranged between the other lever of the elbow lever system and the switching lever.
  • the points of connection of the spring is chosen so that the spacing therebetween is essentially maintained during the breaker closing operation. No restoring force of the elbow lever system must therefore be overcome .when the breaker is closed.
  • the tension spring is tensioned only when the breaker opens whereby the restoring force is made available.
  • the first resilient means is a tension spring and one of the lever parts of the lever means is a switching lever rigidly mounted on the switching shaft.
  • An other one of the lever parts is an idler lever pivotally mounted on the switching shaft and a further one of the lever parts is a coupling lever arranged between the switching lever and the idler lever.
  • a still further one of the lever parts is an elbow lever made up of two lever arms pivotally connected to each other. One of the lever arms of the elbow lever is articulately joined to the idler lever.
  • the switching lever and the other one of the lever arms of the elbow lever have respective spring mounts disposed thereon so as to maintain an approximately constant spacing therebetween as the switching shaft is rotated from the first position to the second position, the tension spring being arranged between the spring mounts.
  • FIG. 1 is a schematic diagram of a power circuit breaker for low voltage according to the invention.
  • the diagram shows essentialelements of the latching mechanism and the drive mechanism of the power circuit breaker.
  • FIG. 2 is a detailed schematic diagram of the latching mechanism shown separately in an enlarged scale.
  • the latching mechanism is in its open position with the latching lever locked.
  • FIG. 3 shows a schematic diagram similar to FIG. 2 and shows the latching mechanism in two different positions, namely. at the start and at the end of the breaker opening operation.
  • FIG. 1 a power circuit breaker 1 is shown which is equipped with a drive mechanism 2.
  • the current path of the power circuit breaker 1 includes an upper terminal block 3 and a stationary contact 4 rigidly connected therewith.
  • a movable contact 5 is disposed opposite contact 4.
  • a bendable conductor section 7 is arranged between the contact 5 and a lower terminal block 6.
  • parallel conductor sections 10 andv 11 Between the fixed contact 4 and the movable contact 5 are situated parallel conductor sections 10 andv 11, which for high currents cause an increase of the contact pressure between the contacts 4 and 5.
  • the latching mechanism of .the power circuit breaker 1 which is shown in FIG. 1 includes a switching shaft 12 with a two-arm lever 13 having a lever arm 14 connected with an elbow lever system which in its entirety is designated by reference numeral 15 and having another lever arm 16 engaging the movable contact 5 by means of a lever 17.
  • a link 20 serves to guide the movable contact 5.
  • the movable contact 5 and the conductor section 11 connected therewith is further engaged by a spring 21 which generates the contact pressure in the closed breaker position and also opens the movable contact when the breaker is switched open.
  • the elbow lever system 15 is braced with the one elbow lever 22 against an interlock device 23.
  • the interlock device 23 comprises a latching lever 24, a latching pawl 25 and a return spring 26 for the latching pawl 25.
  • the drive mechanism 2 connected with the power circuit breaker 1 includes a torsion rod spring 30 which is clamped at one end in a support 31.
  • the torsion rod spring 30 carries a cam 32 at its front end.
  • a projection 33 of the cam 32 can be engaged by a dog 34 which is fastened on a shaft 35 upon which a hand lever 36 acts.
  • the torsion rod spring 30 may be a solid member, but preferably, it is made up of a stack of individual leaf springs.
  • the hand lever 36 is shown in a position just before reaching the closed position indicated by the broken line 37. If the hand lever 36 is moved still further, the dog 34 slides off the projection 33 and releases the cam 32. The cam 32 rotates counterclockwise and presses against a roller 18 arranged at the joint of the elbow lever system 15 until the elbow lever system 15 goes past its dead center position and the elbow lever 22 comes to rest against a stop 28. The described motion of the elbow lever system 15 causes a clockwise rotation of the switching shaft 12 and therefore the closing of the power circuit breaker 1.
  • the switching shaft 40 corresponds to the switching shaft 12 shown in FIG. 1.
  • the levers 42 and 43 form the elbow lever system designated by reference numeral 15 in FIG. 1.
  • the lever 43 is pivotally mounted on a stationary bearing post 44 and has an extension 45 which projects out beyond the pivot post 44 and which in the, open position of the breaker according to FIG. 2 rests against a stop 48.
  • the other lever 42 is linked with an idler lever 47 by means of a further pivot pin 49.
  • the idler lever 47 is mounted on the switching shaft 40'and has a working surface 50 which coacts with a roller 52 of a roller lever 51.
  • the roller lever 51 is supported by means of a pivot pin 53 on a switching lever 54 which is rigidly connected with the control shaft 40.
  • a further roller 55 is provided and is guided on a circular track 57 of a latching lever 56.
  • the latching lever 56 is of approximately sickle-shaped configuration and is pivotally mounted at its one end about a pin 60.
  • the latching lever 56 has a nose 62 which, in the closed position, rests against a tripping shaft 63.
  • a fixed stop 68 limits the travel of the latching lever 56 when the breaker switches to the open position.
  • a long bendable spring 65 is engaged at the end of the switching lever 54 at the end of the switching lever 54 there is an opening 61 wherein a long bendable spring 65 is engaged.
  • the spring 65 is guided between the stationary stops 66 and 67 and coacts with a stop 70 of the latching lever 56, the stop 70 being in the region of the circular track 57.
  • the switching lever 54 further has a rear extension 71 at which a pin 73 is arranged as the anchor for a tension spring 72. With its other end, the tension spring 72 engages the anchor point 74 of the extension 45 of the elbow lever 43.
  • the nose 62 of the latching lever 56 is released by rotating the tripping shaft 63.
  • the latching lever 56 thereby assumes the position shown by solid lines in FIG. 3.
  • the roller 52 of the roller lever 51 slides off the working surface 50 of the idler lever 47 and the switching lever 54 with the switching shaft 40 rotate to arrive in the open position under the influence of the stored breaker opening force as shown by the brokenline contour in FIG. 3.
  • the point of application of the bending spring 65 on the switching lever 54 moves along a circular line during the opening operation which has the consequence that the bending spring 65 lies against the stop 70 of the latching lever 56 and is bent in such a manner that a re storing force is exerted on the latching lever 56.
  • a comparison of FIGS. 2 and 3 shows that the bending stress in the open position is greater than in the closed positlon.
  • FIG. 3 shows furthermore that the movement of the switching lever 54 from the closed position to the open position is accompanied by a tensioning of the tension spring 72 thereby making available the restoring force which is necessary to bring the elbow levers 42 and 43 into the position corresponding to FIG. 1.
  • An electric power circuit breaker comprising contact means switchable between open and closed positions; a latching mechanism for actuating said contact means; and a drive mechanism operatively connected to said latching mechanism for initiating the closing of said contact means by said latching mechanism; said latching mechanism including: a switching shaft operatively connected to said contact means and rotatable between first and second positions corresponding to said open and closed positions of said contact means respectively, lever means responsive to said drive mechanism for rotating said switching shaft from said first position to said second position, said lever means having a plurality of interacting lever parts movable between an initial position and an end position corresponding respectively to said first and second positions of said shaft, a latching lever coacting with said lever means to hold said switching shaft in said second position, tripping means releasably engaging said latching lever for releasing said latching lever to withdraw said hold on said lever means, breaker opening means operatively connected to said shaft for moving said shaft from said second position to said first position when said latching lever is released by said tripping means, first resilient means connected
  • said latching lever being pivotally mounted at one end thereof and having a bracing stop disposed thereon for bracing said second spring
  • said tripping means being a tripping shaft releasably engaging the other end of said latching lever
  • said latching mechanism including stationary anchor means for bracing said second spring.
  • said second spring being a bending spring articulately joined to said switching lever and drawn about said bracing stop to increase the bending stress in said bending spring as said switching lever moves with said switching shaft from said second position to said first position.
  • said first resilient means being a tension spring
  • one of said lever parts of said lever means being a switching lever rigidly mounted on said switching shaft
  • an other one of said lever parts being an idler lever pivotally mounted on said switching shaft
  • a further one of said lever parts being a coupling lever arranged between said switching lever and said idler lever
  • a still further one of said lever parts being an elbow lever comprising two lever arms pivotally connected to each other, one of said lever arms of said elbow lever being articulately joined to said idler lever, said switching lever and said other one of said lever arms of said elbow lever having respective spring mounts disposed thereon so as to maintain an approximately constant spacing therebetween as said switching shaft is rotated from said first position to said second position, said tension spring being arranged between said spring mounts.
  • said drive mechanism including force generating means arranged with respect to said elbow lever of said latching mechanism for imparting a force thereto whereby said elbow lever coacts with said idler lever, said coupling lever and said switching lever to transmit said force to said switching shaft.
  • said second resilient means being a bending spring
  • said latching lever being pivotally mounted at one end thereof and having a bracing stop disposed thereon for bracing said bending spring
  • said tripping means being a tripping shaft releasably engaging the other end of said latching lever
  • said latching mechanism including stationary anchor means for bracing said bending spring, said bending spring being articulately joined to said switching lever and drawn about said bracing stop to increase the bending stress in said bending spring as said switching lever moves with said switching shaft from said second position to said first position.

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  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
  • Mechanisms For Operating Contacts (AREA)
  • Breakers (AREA)
US00352202A 1972-04-19 1973-04-18 Electric power circuit breaker equipped with a latching mechanism wherein restoring forces are provided as a function of switching shaft position Expired - Lifetime US3835275A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE2219892A DE2219892C3 (de) 1972-04-19 1972-04-19 Elektrischer Leistungsschalter mit einem SchaltschloB

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US3835275A true US3835275A (en) 1974-09-10

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US00352202A Expired - Lifetime US3835275A (en) 1972-04-19 1973-04-18 Electric power circuit breaker equipped with a latching mechanism wherein restoring forces are provided as a function of switching shaft position

Country Status (6)

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US (1) US3835275A (no)
JP (1) JPS559774B2 (no)
DE (1) DE2219892C3 (no)
FR (1) FR2202359B1 (no)
GB (1) GB1426642A (no)
IT (1) IT982037B (no)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4146765A (en) * 1976-10-22 1979-03-27 Gould Inc. Circuit breaker closing mechanism
US4167659A (en) * 1976-01-06 1979-09-11 Mitsubishi Denki Kabushiki Kaisha Operation mechanism of switch
US4439653A (en) * 1981-03-19 1984-03-27 Tokyo Shibaura Denki Kabushiki Kaisha Circuit breaker operating apparatus
US6864450B1 (en) * 2004-05-19 2005-03-08 Eaton Corporation Circuit breaker with delay mechanism
CN101320636B (zh) * 2007-03-29 2013-02-27 伊顿公司 用于关闭电气开关装置的弹簧驱动活塞
WO2015080934A1 (en) * 2013-11-27 2015-06-04 Eaton Corporation Electrical switching apparatus and opening assembly therefor having engagement lug

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58180385A (ja) * 1982-04-16 1983-10-21 Nissan Motor Co Ltd 後部車体構造

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3095489A (en) * 1960-10-20 1963-06-25 Gen Electric Manual charging means for stored energy closing mechanisms of electric circuit breakers
US3098134A (en) * 1960-07-02 1963-07-16 Coq Nv Driving mechanisms for electric circuit-breakers
US3600541A (en) * 1969-11-06 1971-08-17 Allis Chalmers Mfg Co Circuit breaker operating mechanism having torsion bar springs

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3098134A (en) * 1960-07-02 1963-07-16 Coq Nv Driving mechanisms for electric circuit-breakers
US3095489A (en) * 1960-10-20 1963-06-25 Gen Electric Manual charging means for stored energy closing mechanisms of electric circuit breakers
US3600541A (en) * 1969-11-06 1971-08-17 Allis Chalmers Mfg Co Circuit breaker operating mechanism having torsion bar springs

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4167659A (en) * 1976-01-06 1979-09-11 Mitsubishi Denki Kabushiki Kaisha Operation mechanism of switch
US4146765A (en) * 1976-10-22 1979-03-27 Gould Inc. Circuit breaker closing mechanism
US4439653A (en) * 1981-03-19 1984-03-27 Tokyo Shibaura Denki Kabushiki Kaisha Circuit breaker operating apparatus
US6864450B1 (en) * 2004-05-19 2005-03-08 Eaton Corporation Circuit breaker with delay mechanism
CN101320636B (zh) * 2007-03-29 2013-02-27 伊顿公司 用于关闭电气开关装置的弹簧驱动活塞
WO2015080934A1 (en) * 2013-11-27 2015-06-04 Eaton Corporation Electrical switching apparatus and opening assembly therefor having engagement lug
US9362064B2 (en) 2013-11-27 2016-06-07 Eaton Corporation Electrical switching apparatus and opening assembly having an engagement lug
CN105765682A (zh) * 2013-11-27 2016-07-13 伊顿公司 电气开关设备和具有接合突耳的用于电气开关设备的断开组件
CN105765682B (zh) * 2013-11-27 2018-08-03 伊顿公司 电气开关设备和具有接合突耳的用于电气开关设备的断开组件

Also Published As

Publication number Publication date
GB1426642A (en) 1976-03-03
FR2202359B1 (no) 1977-07-29
FR2202359A1 (no) 1974-05-03
DE2219892B2 (de) 1975-02-27
IT982037B (it) 1974-10-21
JPS4916864A (no) 1974-02-14
DE2219892A1 (de) 1973-10-31
DE2219892C3 (de) 1975-10-16
JPS559774B2 (no) 1980-03-12

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