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US2663779A - Protecting device for circuit breakers - Google Patents

Protecting device for circuit breakers Download PDF

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Publication number
US2663779A
US2663779A US287834A US28783452A US2663779A US 2663779 A US2663779 A US 2663779A US 287834 A US287834 A US 287834A US 28783452 A US28783452 A US 28783452A US 2663779 A US2663779 A US 2663779A
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US
United States
Prior art keywords
shaft
contacts
movable
movement
closing
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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
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US287834A
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English (en)
Inventor
Viboud Albert
Gras Andre
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.)
Merlin Gerin SA
Original Assignee
Merlin Gerin SA
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 Merlin Gerin SA filed Critical Merlin Gerin SA
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Publication of US2663779A publication Critical patent/US2663779A/en
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Classifications

    • 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
    • H01H71/1054—Means for avoiding unauthorised release

Definitions

  • the invention is concerned with a device for protecting circuit breakers against unintentional closing of the contacts.
  • unintentional closing may for instance occur when the circuit breaker or switch of any type, with at least one fixed or stationary contact and at least one movable contact, is employed in any switching apparatus, switch box, on a switch board, panel, or the like of a mobile station on any vehicle, ship, railroad, aircraft, or any other mobile conveyance which during its locomotion is exposed to vibrations or sudden shocks, such as from change of direction or speed r other causes.
  • stationary is to be understood to relate to those parts which are fixed or per manently at rest at the switching apparatus and in the mobile vehicle which parts, however, of course move together with, but not relatively to, the mobile vehicle.
  • the contacts opposite to, and cooperating with a.
  • the stationary contact are the movable contacts.
  • movable contacts such as blades, knives, brush contacts, face contacts, or the like.
  • the invention particularly relates to such movable contacts carried on a shaft through the turning of which the contacts are closed and opened.
  • These contacts carried on a shaft may be the movable main contacts or the movable contact of a circuit breaker or switch or they may be auxiliary contacts, or an auxiliary contact, such as conventional in the art or convenient for preventing the formation of the are, or arcing the arc, or extinguishing or blowing out the arc.
  • the invention is concerned primarily with the actuating means of the movable contact or contacts in circuit breakers or switches of the aforesaid type and a primary object of the invention is a development of such actuating means which prevents the movable equipment or mechanism of the circuit breaker from, or protect it against, being moved unintentionally to such an extent that the movable contacts or contact might engage the stationary contacts or contact.
  • Such unintentional engagement might occur when, during or through the operation of the vehicle or the like, vibrations or shocks are produced of an intensity sufficient to cause movement of the movable mechanism or equipment through its inertia relatively to the stationr contacts to an extent that the movable m contacts or arcing or other auxiliary contacts or contact engage, even if only transitorily, the stationary contacts or contact and the current is switched on, if even to be interrupted immediately thereafter.
  • a further object of the invention is to apply this inpeding mechanism to the actuating shaft of the movable equipment in such a manner that the mechanism is unidirectionally operative or eiiective, i. e., that the impeding mechanism distinguishes between movements in the opening sense and movements in the closing sense so as to allow the circuit breaker or switch to be opened unimpededly.
  • the impeding mechanism is to impede movement of the shaft, in the other case it is to release such movement.
  • the protecting device for circuit breakers with p at least one contact pair having a stationary and a movable contact, a shaft carrying the movable contact, and actuating means for closing and opening the contacts, in accordance with the invention thus includes a unidirectionally selective impeding mechanism associated with the shaft.
  • This impeding mechanism is adapted for taking up turning moments caused, on coerced movement of the circuit breaker as a whole, through inertia of the movable contact and produced by, and arriving at the impeding mechanism from, movement of the movable contact relatively to the stationary contact and in the closing sense, unintentional closing of the contacts thus being avoided.
  • the impeding mechanism is further adapted to release the shaft for movement by turning moments produced at the shaft by intentional actuation of the actuating means for operation of the circuit breaker in either sense, opening and closing the contacts.
  • the impeding mechanism may be of various types.
  • the mechanism may thus be unidirectionally'responsive to angular displacement of the shaft in the closing sense.
  • the mechanism will thus be unresponsive to movements of the shaft in the opening sense but Will respond to angular displacement of the shaft in the closing sense and selectively will resist such movement during a first certain angle of this movement in the closing sense while it will release its resistance when the shaft has been moved above this angle. In this way unintentional closing of the contacts is prevented when the movable contact through its inertia moves out of its open position.
  • the contacts however may be intentionally closed when, by means of the actuating means, the shaft is moved through and above this angle.
  • the mechanism which resists the unintentional closing of the contacts includes a sta tionary member, that is, stationary relatively to the stationary part or equipment of the circuit breaker, further includes a movable member disposed on the shaft and interengaging means which are unidirectionally responsive to angular displacement of the shaft in the closing sense.
  • This resisting mechanism may include a brake r mechanism with means which, during a first certain angle of displacement of the shaft relatively to the stationary parts of the circuit breaker, cause the brake members to engage each other and thus to brake and impede the movement of the shaft. These means, when through intentional operation of the shaft the resistance of the brake mechanism has been overcome and the shaft has moved through and above this angle, will then release the brake members from engagement and allow the shaft to be freely moved by the actuating means for closing the contacts.
  • the resisting mechanism may be so designed that the energy of even the greatest shock as might occur and act upon the movable equipment of the circuit breaker in the sense of closing the contacts is absorbed through the frictional moment before the fixed and movable main contacts or arcing contacts might touch each other.
  • the action of the frictional moment ceases as soon as by intentional operation of the actuating means the angular displacement has reached a certain predetermined value and the frictional resistance on this path once has been overcome.
  • the impeding device may include a locking mechanism comprising a stationarily mounted locking member and cooperating therewith a stop member mounted on, and secured to, the shaft and engaging the locking member in the "open position of the shaft, i. e. the position of the shaft where the contacts are open.
  • a release member is secured to the actuating means to be actuated thereby for lifting the locking member out of engagement with the stop member when the actuating means are moved in the sense to close the contacts.
  • Coupling means are provided which, on disengagement of the locking mechanism, couple the actuating means and the shaft for closing the contacts by actuation of the actuating means.
  • Unintentional closing of the contacts out of the open position of the movable contact or equipment is thus prevented how intensive the shocks or vibrations may be, but intentional closing and opening of the contacts is made possible without any hindrance.
  • Fig. 1 is an elevational front view of a switch with actuating means and protecting device of the invention embodied as a resisting mecha- .ism, and more particularly a brake mechanism;
  • Fig. 2 is a similar view of the resisting mechanism of Fig. 1 partly in section, taken on line 2-2 of Fig. 4, and on an enlarged scale;
  • Fig. 3 is an elevational side view taken along line 3-4; of Fig.1;
  • Fig. 4 is an elevational section, along line 4*"6 of Fig. 1, the brake mechanism being in its disengaged position for a switch in it closed position;
  • Fig. 5 is the same sectional view, the brake mechanism being in its engaged position for the switch in its open position;
  • Fig. 6 is an elevational front view of a second embodiment of the invention embodied as a locking mechanism for a switch or circuit breaker for manual operation as well as for operation by remote control;
  • Fig. 7 is a side view taken along line 7-! of 6 showing diagrammatically the switch or circuit breaker of Fig. 6;
  • Fig. 8 is a view similar to that of Fig. 6 partly in longitudinal section along line 8-8 of Fig. 9 of the locking device mechanism and on an enlarged scale;
  • Fig. 9 is a section along line 9---! of Fig. 8;
  • Figs. 10 to 13 are side views of the manually operated part of the locking mechanism in Various positions;
  • Fig. 14 is a diagrammatic perspective of the remote control part of the locking mechanism of Figs. 6 and 8;
  • Figs. 15 and 16 are side views of details of the remote control part of the locking mechanism.
  • a switch or circuit breaker of any type is schematically indicated at H.
  • I2 are the fixed or stationary contacts
  • I 3 the movable contacts such as in the form of blades, knives, brushes, or the like.
  • the shaft which carries the movable contacts or contact 13 is designated by M.
  • the shaft l4 may be actuated by any c0nVenient or conventional means, by remote control or, as indicated, by a handgrip I5.
  • Shaft I 4, handgrip l5, and blades I 3, in this instance, represent the movable equipment of the switch.
  • the unidirectionally selective impeding mechanism is a resisting mechanism' with a stationary member, a movable member disposed on the shaft to be movable therewith, and with interengaging means responsive to angular displacement of the shaft in the closing sense.
  • the stationary member is the brake casing I 8.
  • the casing is fixed to the switch panel or other stationary structure, not shown, by a rod system including an adjustable rod 48 secured to casing [8 by means of a holding plate riveted to the casing.
  • the brake casing is rotatably carried on shaft M by means of a sleeve 2i with its one end extended into the casing l3 and provided at this end with a flange 25. At the other, the outside end, the sleeve is provided with a screw thread 22.
  • furthermore is shaped with two fiattenings 23, 24, at opposite sides, and the casing I8 is correspondingly perforated, so that casing l8 and sleeve 2
  • An adjusting ring 26 is screwed on the sleeve and adjusted in its position by means of set screw 2! which sets on one of the flattenings, in the instance illustrated, the lower one, 24.
  • a flanged bush 28 Secured to the casing l8, for instance riveted, is a flanged bush 28, between whose flange 29 and the adlusting ring '26 a coil spring 38 is extended which thus urges the sleeve with its flange 22 towards the casing 18.
  • the movable member of the resisting mechanism is a carrier disc 3! which by means of a pin 32 is secured to shaft 44.
  • carries a number of pawls 35, in the present instance three, evenly distributed over the circumference.
  • the pawls 35 are freely turnable about their pivots 36.
  • the ratchet wheel 38 is provided at both its sides with annular discs 33, 40, of any conventional or convenient brake lining material, Together with these discs or brake linings ratchet wheel 38 is circularly perforated so as to be freely revolvable about sleeve 2
  • is likewise keyed by the flattenings 23, 24, against peripheral displacement but axially displaceable on sleeve 2! and is seated between flange and the adjacent annular disc or brake lining 39.
  • the movable brake member 39, 33, All, however, is not coupled with the shaft in a unique sense so that it would be coupled in any condit on w th the shaft and the carrier disc 3! of the device thereon when the shaft M with sh. is turned clockwise, Figs. a and 5, or in the sense of arrow F in Fig. 2, the sense in the clrcult breaker is to be closed.
  • the movable br ke member rather forms part of the interengag 1g mechanism which imparts to the impeding or resisting mechanism unidirectional and selective characteristics.
  • the pawls ensure potentially to the shaft may be engaged with the brake when the shaft is turned in the closing sense, they ensure A strong braking also that the shaft remains disengaged from the brake mechanism when the shaft is turned in the opposite, the opening sense.
  • the inter-engaging mechanism so far is unidirectional. But it is also selective through the following release mechanism operable through the angular displacement of the shaft.
  • This release mechanism comprises rollers 32 at the free ends of the pawls which when riding on the inside surface of the cylindrical wall 44 of the casing I8 will lift the pawls 35 out of engagement with the ratchet wheel 32- but when reaching windows 43 provided in wall it will release the pawls 35 to be urged by the springs into engagement with the ratchet wheel 33.
  • each pawl may either ride on the cylinder wall of the easing and on and during contact with this wall will lift the pawl nose out of engagement with the toothed rim of the ratchet wheel or that the roller on its path will find and enter a window and will thus release the pawl for engagement with the ratchet wheel.
  • the function of the device is as follows:
  • the casing I8, 44, with its windows 43 is so a ljusted by means of the adjustable rod it that in the open position of the circuit breaker the rollers 42 of the pawls 35 may enter the windows If in this open position of the circuit breaker a shock or vibrations act upon the movable equipmerit of the switch and move blades l3 and handgrip l5 of the movable equipment, these parts, since they are secured to the shaft, will take the shaft l4 along and tend to turn it in the closing sense, arrow F in Figs. 2 and 4.
  • the disc 3! which is keyed to shaft it turns together with the shaft. Since the rollers have entered the windows 43, the pawls 35 engage the ratchet wheel 38, and tend to take it along.
  • the ratchet wheel however offers strong resistance to this movement in View of the great friction which is produced between the linings 40, and the metal discs l4, l8, respectively. energy of the shock will thus be absorbed by friction.
  • the pressure of spring 30 and the peripheral lengths of the windows are so determined that intensity and duration of friction suince to absorb the greatest shock energy which might occur. It is obvious that the absorption of the shock energy must be accomplished principally by the intensity of the friction and that thewfore a very strong spring 30 is to be applied since the length of time during which the friction is efiec tive corresponds to the angular displacement of disc 3
  • the frictional moment produced in the brake mechanism is or course to be overcome when the switch or circuit breaker is to be closed tentionally. If the brake mechanism were cc operative over the whole angular displacement of the switch from the "open to the closed position, this would tend to slow down the closing movement, whereas, to the contrary, the movable contacts, at the moment of closing, should have a very great velocity.
  • the invention therefore provides, that after a certain time, or after a certain angle of travel has been completed, the efiect of the frictional moment ceases.
  • This end is achieved by determining and disposing the peripheral lengths of the windows in relation to the uninterrupted peripheral lengths of the cylinder walls, from window to window, so that as soon as the angle corresponding to the peripheral length of a window and provided for the absorption of the shock energy has been traversed, the rollers reach the uninterrupted arc of the cylindrical wall 44, are pressed inwards while continuing their course.
  • the pawls 35 will now be pivoted about their pivots 36 and their noses will thus be lifted out of engagement with the ratchet wheel 38.
  • the ratchet wheel will no longer be turned, the frictional moment vanishes, and the closing movement may be completed without any further hindrance.
  • the duration of the frictional coupling may be regulated through adjustment of the position of the casing M3 by varying the length of rod i9 and thus changing the position of the rollers 35 in the open position relatively to the edges of the windows 43 and correspondingly the magnitude of the angular displacement during which the frictional moment or couple is effective.
  • the device as just described may absorb not only the energy of an accidental shock but also that of oscillations of a certain range. As soon as the undesired or unintentional influences have ceased, the shaft will return under the influence of the gravity of the movable equipment into the normal open position of the circuit breaker or switch and the device is again ready for function.
  • Figs. 6 to 16 illustrate an embodiment wherein the shaft which carries the movable contacts or contact and the actuating means will be coupled together for actuation and will then be disconnected from one another.
  • the device which protects the switch or circuit breaker against unintentional closing through inertia of the movable equipment and caused by coerced movement of the circuit breaker as a whole includes a locking mechanism for locking the shaft against unintentional movement.
  • i I again indicates schematically a switch or circuit breaker of any type with the stationary contact or contacts l2 and the movable contact or contacts l3, carried by the shaft
  • the means for operating the switch manually is the handgrip 52 and the actuating means for remote control are an electromagnet T4 with armature 15, levers 11 and 82, and sleeve 83, as may be seen from Figs. 6, 8, and 9, the details of the members for manual control being shown in Figs. to 13 and those for remote control in Figs. 14 to 16.
  • the locking mechanism which prevents the switch from being closed unintentionally and which looks the shaft 5
  • Support 53 is secured by any conventional means, not shown, to the panel of the switch or other structure supporting the same.
  • a leaf spring 51 secured to the support urges the locking bar 52 upwards against a stop member in form of a cam 55 mounted upon and secured to shaft 5
  • Cam 55 of generally semi-circular contour is shaped with a notch or indentation 56 into which the locking bar 52 will enter when shaft 5
  • Notch or indentation 56 will thus serve as a stop, preventing shaft 5
  • the release members for the locking bar 52 are two cams 59 and 50 both loosely mounted on shaft 5
  • One cam, 59, for manual 0 eration is secured to the handgrip 52, loosely mounted on shaft 5
  • the other cam 60, for remote control is secured to sleeve 83 likewise loosely mounted on shaft 5
  • Handgrip 62 terminates in a fork 53 by means of which it is loosely mounted on shaft 5%.
  • Cam 59 is secured, by soldering, brazing, or welding, for instance, to one branch of the fork.
  • the branches of fork 53 embrace cam 55 and opposed thereto carry a pawl 55 loosely pivoted at $5.
  • the pawl 55 is so suspended that its center of gravity is below its pivot 55, as shown in the rest position of handgrip 52 is Fig. 9, and where the pawl bears with its tail end against an abutment pin 66 which prevents undesired deflection of the pawl in the one direction.
  • the upper contour Bl of the pawl is so shaped that in this position, Fig. 9, the pawl just clears the unindented semi-circular contour of cam 55, so that this cam may unimpededly pass the pawl when the cam is turned together with shaft 5
  • Cam 55 and together with it shaft 5! are thus released for movement or actuation in the closing sense.
  • the arc contour of cam will hold the locking bar disengaged.
  • the upper contour of the pawl will no longer be guided along the contour of cam 55 and no longer be held with its tail end against abutment pin 55, but will by its gravity turn about pivot 55 and snap with a corner notch 58 over edge 58 of cam 55.
  • Lever. i! which is? pivoted to a stationary pivot 5.9 is linked by means. of rod- Hi and pivot 73 to the armature P5 of: the electromagnet T4 for remote control.
  • the free: end 88 of lever i? is. formed as a hook againstwhich bears the end 3-! of: a lever 82- securedv tosleeve 33.
  • the other end 85 of lever 82' is forked.
  • the fork 85 em braces with clearance a: crank pin 89 of a crank arm 58 which is secured to shaft 5
  • Lever 82-, 85 is so. shaped, as Figs. 9 and 1a illustrate, that its: center of graviiry is eccentric: and is lying towards? the fork side of lever 82: sothat the resulting moment. of gravity will tend to turn lever 82- and. with it sleeve 83 m asense opposite to that of arrow H, or counterclockwise;
  • Lever 82, 35 is: secured to sleeve 83' and crank 82, 89, to shaft 51- so.
  • Intended closing of the switch may be achieved simply by manipulating the handgrip in the case of manual operation as described hereinbefore, or, in the case of remote control, by excitingv the electromagnet M.
  • the closing by remote control comprises two phases. The first phase in which the shaft 5i is unlocked and the second phase in which the switch is closed by turning the shaft.
  • Hook 8i deflects the fork lever 82 clockwise, in the sense of arrow H.
  • the fork 85 before it strikes crank pin 89, moves first idly, a path a,
  • cam rise 93 of cam '65 will rock the locking bar 52 and lift the bar out of engagement with the indentation 56 of cam 55, and will then hold the locking bar in inactive position, out of engagement, on the circular circumference of cam 68;
  • Cam 55 and with it shaft 5-! are thus released for movement or actuation in the closing sense, unimpeded also by the cam mechanism operable by the manual actuating means.
  • said device including a unidirectionally selective impeding mechanism having a movement resisting member mounted at said circuit breaker independently of said shaft, a member rigidly secured at said shaft to be movable therewith and adapted for unidirectional engagement with said resisting member thereby to take up turning moments caused on coerced movement of said circuit breaker as a whole through inertia of the movable contact and produced by, and arriving at said impeding mechanism from, movement of the movable contact, and resist any unintentional closing movement of the contacts; said impeding in chanism further including release mechanism associated with said actuating means and operable thereby for disengaging said shaft member from said resisting member and thus to release the shaft for movement by turning moments produced at the shaft by intentional actuation of the actuating means for operation of the circuit breaker in either sense, opening and closing the contacts.
  • said interengaging mechanism comprises a pawl and ratchet wheel gearing; said ratchet wheel being secured to the movable brake member; a carrier disc mounted on the shaft and secured thereto, the pawl being pivotally mounted on the carrier disc, spring means, associated with the pawl, being secured to'the carrier disc and adapted to urge the pawl at the one end thereof into engagement with the ratchet wheel, stationary control means being associated with the other end of the pawl and adapted to release the pawl on a certain angle of its rotary movement with the carrier disc and shaft, out of the open position of the contacts, for engagement with the ratchet wheel, and, on rotary movement above said angle, to lift the pawl out of engagement with the ratchet wheel.
  • said stationary control means includes a stationary cylindrical casing loosely disposed on the shaft and with its cylindrical wall surrounding said carrier disc, the free end of the pawl being disposed and adapted to ride on the inside surface of said cylindrical wall, the pawl on contact with the wall thereby being lifted out of engagement with the ratchet wheel, windows being provided in said wall and on the path of the pawl, the peripheral lengths of the windows being determined and disposed in relation to the uninterrupted peripheral length of the Wall from window to window so as to release the pawl for engagement with the ratchet wheel on said certain angle of the shaft angular displacement.
  • Protecting device as set forth in claim 8 wherein said actating means comprise switch- 5 Number ing means for manual operation and switching means for remote control; each separately provided with a release cam secured thereto and separately loosely mounted on the shratt; the locking member being a bar pivotally mounte on said support; said stop member being a cam with a stop thereon and mounted on and secured to the shaft, a spring being provided at said support disposed and adapted to urge the locking bar against the stop can; the release cams being adapted for cooperation with the locking bar, thereby, on actuation of any of said two switching means to lift the locking bar out of engagement with the stop of the stop cam.

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  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Driving Mechanisms And Operating Circuits Of Arc-Extinguishing High-Tension Switches (AREA)
US287834A 1951-05-31 1952-05-15 Protecting device for circuit breakers Expired - Lifetime US2663779A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR1037914T 1951-05-31

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US2663779A true US2663779A (en) 1953-12-22

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US287834A Expired - Lifetime US2663779A (en) 1951-05-31 1952-05-15 Protecting device for circuit breakers

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2744179A (en) * 1953-02-02 1956-05-01 Mcgraw Electric Co Air disconnect switch
DE1276171B (de) * 1960-03-24 1968-08-29 Licentia Gmbh Bei Stoessen wirksame Sperreinrichtung fuer bewegliche Teile elektrischer Schaltgeraete, z. B. Schuetze
WO2000067274A1 (fr) * 1999-04-28 2000-11-09 Siemens Aktiengesellschaft Unite coupe-circuit

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2438373A (en) * 1946-04-12 1948-03-23 Gen Electric Electric switch

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2438373A (en) * 1946-04-12 1948-03-23 Gen Electric Electric switch

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2744179A (en) * 1953-02-02 1956-05-01 Mcgraw Electric Co Air disconnect switch
DE1276171B (de) * 1960-03-24 1968-08-29 Licentia Gmbh Bei Stoessen wirksame Sperreinrichtung fuer bewegliche Teile elektrischer Schaltgeraete, z. B. Schuetze
WO2000067274A1 (fr) * 1999-04-28 2000-11-09 Siemens Aktiengesellschaft Unite coupe-circuit

Also Published As

Publication number Publication date
FR1037914A (fr) 1953-09-23

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