US2199477A - Releasing device for electric switches - Google Patents

Releasing device for electric switches Download PDF

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US2199477A
US2199477A US186673A US18667338A US2199477A US 2199477 A US2199477 A US 2199477A US 186673 A US186673 A US 186673A US 18667338 A US18667338 A US 18667338A US 2199477 A US2199477 A US 2199477A
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abutment
releasing
thermal
elements
bimetallic
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US186673A
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Besag Ernst
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    • 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
    • H01H71/42—Induction-motor, induced-current, or electrodynamic release mechanisms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H53/00—Relays using the dynamo-electric effect, i.e. relays in which contacts are opened or closed due to relative movement of current-carrying conductor and magnetic field caused by force of interaction between them
    • H01H53/10—Induction relays, i.e. relays in which the interaction is between a magnetic field and current induced thereby in a conductor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
    • H01H83/00—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current
    • H01H83/20—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by excess current as well as by some other abnormal electrical condition
    • H01H83/22—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by excess current as well as by some other abnormal electrical condition the other condition being imbalance of two or more currents or voltages
    • H01H83/223—Protective switches, e.g. circuit-breaking switches, or protective relays operated by abnormal electrical conditions otherwise than solely by excess current operated by excess current as well as by some other abnormal electrical condition the other condition being imbalance of two or more currents or voltages with bimetal elements

Definitions

  • the present invention relates to releasing devices for multipolar electric switches of the type in which a plurality of thermal or thermally-responsive releasing ,elements are employed for the purpose of releasing the switch on the occurrence of an inadmissible load. From a more limited point of View, the invention relates to releasing devices which are adapted to release automatic Aswitches on the occurrence of overloads, or loads of inadmissibly high current strength or amperage and duration, after the lapse of a predetermined time lag, on the occurrence of smaller loads when said loads are unsymmetrical. Such releasing devices are used, for example, in threephase-current net works for the protection of three-phase motors.
  • the releasing elements themselves act, at the same time, to actuate the other abutment member over the same distance,'in opposition to the force exerted upon it by the other spring.
  • the abutment members are actuated as a unit, without any relative movement between them.
  • one of the abutment members is held ⁇ against movement by the thermal releasing element that is subjected to the smallest expansion and the other abutment member is moved according to the rate of expansion of the releasing element that is subjected to the greatest expansion.
  • One of the abutment members is then moved with respect to the other to release the .switch that is controlled by the releasing device.
  • a non-closable switch mechanism should be maintained stationary with respect tothe stationary bearing member of the two abutment members; but it is'not easy to control a stationary mechanism through the medium of the relative movement of two abutment members that are moved as a unit with .respect to said stationary-mechanism according to changes in the working conditions.
  • a further object is to provide a new'and improved releasing device having additional advantages over prior-art releasing devices, as will hereinafter appear.
  • FIG. 1 is a plan view illustrating-an embodiment of the invention with the parts occupying their initial positions, the bearing-member housing being shown in section;
  • Figs. 2 and 3 are similarv views of the releasing deviceillustrated in Fig. 1, with the parts occupying other operating positions;
  • Fig. 4 is a diagrammatic plan ofstill another embodiment of the invention, with the parts occupying initial positions corresponding to those of Fig. 1;
  • Figs. 5 and 6 are views of the releasing device illustrated in Fig. 4, with the parts occupying operating positions corresponding to those shown in Figs. 2 and 3, respectively;
  • Fig. 7 is a diagrammatic perspective of another releasing device embodying the present invention.
  • Fig. 8 is a similar diagrammatic perspective View of a further releasing device according to the present invention.
  • Fig. 9 is a plan illustrating still another embodiment of the invention.
  • thermal or thermally-responsive releasing elements 2a, 2b, 2c that may be constituted of equally shaped bimetallic strips, are fastened, or otherwise secured, as by means of rivets I3, to vertical extensions or ribs 3a, 3b, 3c of a cross bar or fixing member 3.
  • the bimetallic strips are illustrated as riveted to the crossbar 3, this is for convenience only. As will be understood, they may be secured to the bar 3 in anyother desired manner, and they may even abut' loosely against, or otherwise connect with, the ribs vor other parts of the member 3.
  • fixing member To save circumlocution of language, al1 such constructions will be referred to, in the specification and claims, by the term fixing member.
  • the fixing member 3 is constituted of an insulating strip that is mounted to slide longitudinally, to the right and to' the left, as viewed in Figs. l to 6, in a guiding groove Ia of a housing or casing I for the fixing member 3 and the thermally-responsive elements 2a, 2b, 2c carried thereby, and that constitutes a bearing member.
  • the housing is supplied with a cover or equivalent closing means
  • abutment screw '9 may be adjusted along the scale 9a, the head of the screw 3 serving as a pointer or indicator for cooperating with the scale 8a to indicate the position of the screw 3.
  • Abutments 6a 6b, 6c, one correspondingt eachof the releasing elements 2a, 2b, 2c, are carried by an abutment member 6 that, like the xing member 3, is constituted of a strip of insua guiding groove Ib within the bearing housing I.
  • the abutment member 6 is normally maintained yieldingly in a normal or initial position, at the left, by a blade spring 3a that engages adepending hook I9, shown at the left of the abutment member 6 as overlapping the spring 8a.
  • the bimetallic releasing elements 2a, 2b, 2c are respectively heated by means of three heating windings or coils 4a, 4b,. lc that are fixed on the bearing member I.
  • they may be heated directly, by inserting them in thecircuit f the heating current; or a combination of direct and indirect heating may be adopted.
  • the bimetallic strips 2a, 2b, 2c bend, as illustrated in Fig. 2.
  • the housing I carries two binding posts 1 .and 3, constituting connecting terminals of a control circuit, such as the energizing circuit of the actuating electromagnet of a remote-control switch of the electromagnetic-relay type.
  • This switch may interrupt the load circuit to be controlled by the releasing device.
  • the spring 3a is secured to the binding post 8, and normally presses against, so as to make contact with, the binding post 1.
  • the circuit between the binding posts 1 and 3 becomes interrupted. This effects the release of. the switch controlled by the releasing device, as, for example, the said remote-control switch.
  • the desired releasing current strengths may be adjusted by rotatable adjustment of the screw 9, as read oi from the scale 9a.
  • a switch mechanism should be used for the auxiliary switch that, upon its becoming opened in response to movement of the thermal releasing elements 4a, 4b, 4c, will remain in open position until it is closed by means of a handle or other manually actuating device. Otherwise, the main switch, which it is desired to control by the releasing device, might become closed, upon the cooling down of. the releasing elements 2a, 2b, 2c, before removal of the defective conditions that gave rise to the releasing operation and the subsequent opening of the main switch. It is not necessary, however, to illustrate auxiliary switches of this type, because they are well known.
  • the abutment member 6 might be employed to operate a switch lock, or an actuating-and-locking mechanism of a non-closable switch, that is a switch of the-tripfreefromthe handle type.
  • thermal releasing elements of this character that shall have characteristics sumciently alike for this purpose.
  • thermal releasing elements of this character that shall have characteristics sumciently alike for this purpose.
  • bimetallic strips inadmissibly great dierences occur in the individual releasing elements as they emerge from the manufacturing process. These differences ought to be compensated for by individually bending the bimetallic strips or individually adjusting their carrying means or supports.
  • Calibrating and adjusting are rendered particularly facile with the embodiment of the invention illustrated in Fig. 1 by provision for easily removing from the bearing-member housing I, the three releasing elements 2a, 2b,.2c and the fixing member 3 upon which they are mounted, and for replacing them readily after adjustment.
  • this construction therefore, it is possible to test the conformity to one another of the three releasing ele- A ments, in a simple manner, kby means of appropriate mechanical gauges; and, by means of the said gauges, to adjust the releasing elements into such conformity. After such testing and adjusting of the highly sensitive thermal releasing elements by means of the said mechanical gauges, there will be no danger of their subsequently becoming involuntarily or accidentally bent.
  • the fixing member 3 is spaced from an adjustable stop shown as constituted of the screw 9.
  • the stop screw 9 permits movement towards the' left of the fixing member 3 with respect to the abutment member 6, but serves to limit further such movement upon the fixing member 3 becoming moved into engagement with the stop 9.
  • I'he abutment member 6 is normally maintained yieldingly by the blade spring 8a in its normal, or initial position, and the releasing elements 2a, 2b, 2c engage the abutments 6a, 6b, 6c.
  • the thermal releasing elements 2a, 2b, 2c Upon heating of the thermal releasing elements 2a, 2b, 2c, by means of the heating windings 4a, 4b, 4c, the said elements bend, as.il1ustrated in Fig.
  • abutments a, 5b, 5c may be provided.
  • the abutments 5a, 5b, 5c vare stationary with respect to the bearing member or housing I.
  • These abutments are ⁇ illustrated as constituted of lateral projections of one of the sidewalls of the housing I. Therefore, the thermal releasing elements 2a, 2b, 2c are each provided with two abutments, one on each side of each releasing element.
  • the thermal releasing element or elements that are less deformed abut against one or more of the stationary abutments 5a, 5b and 5c, but the more deformed thermal releasing element orelements will move the abutment member 6 against the action of the leaf spring 8a.
  • the device will then operate, therefore, ⁇ as a differential releasing device.
  • the releasing, device of Figsjl to 3 will operate as described above, and if the differential releasing action is not needed, the abutments 5a, 5b,
  • 5c may be -dispensed with.
  • Fig. 1 the three bimetallic strips 2b, 2b, 2c are shown unheated and, therefore, unbent.
  • the three bimetallic strips 2a, 2b, 2c become bent to the same extent, whereupon they will actuate the fixing member 3 towards the left, as shown in Fig. 2.
  • the condition of Fig. 3 obtains under an unsymmetrical load.
  • the bimetallic strip 2a is shown unbent; and being unbent, it abuts against the stationary abutment 5a, thereby preventing the fixing member 3 from being actuated towards the left.
  • the bent bi.- metallic strips 2b and 2c therefore actuate the abutment member 6 toward the right, effecting opening of the auxiliary switch 1, 8, 8a.
  • the magnet system of a main switch of the relay type will thus become deenergized and the load, such as a three-phase-current motor will become disconnected from the mains.
  • the bimetallic-strip thermal releasing elements 2a, 2b, 2c are intermediately mounted on the fixing member 3.
  • a spring 8a shown helical, acts upon ⁇ the abutment member 6 to hold it normally yieldingly in a position at the right. It is, however, slidably movable towards the left, in opposition to the action of the spring 8a..
  • This movable abutment member 6 is provided with three abutments 6a, 6b, 6c for engaging the lower ends of the bimetallic strips 2a, 2b, 2c on their left-hand sides.
  • the stationary abutments 5a, 5b, 5c are disposed at the upper ends of the bimetallic strips 2a, 2b, 2c on their right hand sides.
  • Fig. 4 the said strips are illustrated in their unheated and, therefore, in their undeformed or unbent condition.
  • Fig. 5 the bimetallic strips are shown all bent to 'the same extent due to a symmetrical load of all three phases. They have, therefore, actuated their fixing member 3 towards the right.
  • the stop screw 9 is positioned so as to limit the movement toward the right of the fixing member 3 upon the occurrence of a symmetrical load of inadmissible current strength andduration.
  • abutment member 6 and the iixing member 3 have been described above as 1ongitudinally slidable on'the bearing member I, they may be rendered rotatable or otherwise movable.
  • One such embodiment is illustrated in Fig. 7.
  • the ilxing member 3 that carries the bimetallic strips 2a, 2b, 2c is shown ⁇ journaled, so as to rotate like a shaft, in bearings I8 of a bearing member (not shown). 'I'he free ends of the bimetallic strips 2a, 2b, 2c rest on the stationary abutments 5a, 5b, 5c.
  • Abutment fingers 6a, 6b, 6c engage the sides of the bimetallic strips 2a, 2b, 2c opposite the stationary abutments ⁇ i5a, 5b, 5c.
  • the fingers 6a, 6b, 8c are mounted on a rotatable abutment member or shaft 8 that is journaled inbearings II of a bearing member (not shown).
  • a catch I2 pulled downward by a spring 8a is fixed to the right-hand end of The abutment 'fingers 6a, 8b, 6c, therefore, normally maintain the bimetallic strips 2a, 2b, 2c yieldingly in engagement with the stationary abutmentsia, 5b,
  • a latch I2a is held in its initial position by the catch I2.
  • An additional bimetallic strip 2d is mounted upon the right-hand side of the xing-member shaft 3 to compensate for the influence of the ambient or room temperature onh the bimetallic releasing-strips elements 2a, 2b, 2c.
  • the adjustable stop screw 9 is arranged in the path of movement of the bimetallic compensation strip 2d and its position may be read ofi on the scale 8a.
  • the bimetallic strips On the occurrence of an unsymmetrical load of the three phases, the bimetallic strips, which are subjected to the greater expansion rotate the abutment-member shaft 6 anti-clockwise. Upon a predetermined and very small angle of rotation, the latch I2a, released by the catch '
  • the fixing-member shaft 3 is rotated by the bimetallic strips 2a, 2b, 2c in the direction of the arrow p, whereupon they become bent into the dotted-line positions.
  • the compensation strip 2d abuts against the screw 9, thereby preventing further rotation of the member 3 in the direction of the arrow p. Any additional bending of the bimetallic strips 2a, 2b. 2c thereupon effects a rotation of the abutmentmember shaft 6 anti-clockwise, whereupon the catch I2 releases the latch I2a, thus causing the said switch to be released or tripped.
  • curved bimetallic strips 2a, 2b, 2c are heated by means of the heating coils 4a, 4b, 4c, arranged on the inner sides of the strips.
  • the right-hand ends of the bimetallic strips' 2a, 2b, 2c are pivotally mounted on projections 3a, 3b, 3c of a fixing-member shaft 3 that vis rotatably mounted in bearings III of a bearing member (not shown).
  • the shaft 3 carries the bimetallic compensation strip 2d cooperating with the adjustable stop-screw 8, the position of which may be read off fromthe scale 8a.
  • left-hand ends of the ⁇ bimetallic strips 2a, 2b, 2c areA clamped between the stationary 'abutments 5a, 5b, 5c and the movable abutments 8a, 8b, 8c, the latter being constituted of fingerlike projections on the abutment-member shaft 8, rotatably mounted in bearings II.
  • the abutment 8c is bell-crank shaped to form a catch I2 holdingin position the latch I2a.
  • the spring 8a connects catch I2 with the latch I2a.
  • the mode of operation of the releasing device shown in Fig. 8 is the same as that shown in Fig. 7.
  • a hublike ⁇ fixing member 3, carrying the bimetallic strips 2a, 2b, 2c, is rotatably mounted on an axle I5, secured to the bottom of the cylindrical bearing member I.
  • Ihe bimetallic strips 2a,l 2b, 2c are clamped between pairs of abutments 5a and 8a, 5b and 8b, and 5c and 8c.
  • the abutments 8a, 5b, 5c are stationary and form part of the bearing member.
  • the abutments 8a, 6b, 8c are constituted of radial projections of an abutment member 8 that is rotatable about the axle I5 independently of the iixing member I.
  • the abutment member 6 is acted upon by a spring I1 that tends to rotate the abutment member clockwise, in order to maintain the releasing elements 2a, 2b and 2c clamped between the respective pairs of xed and movable abutments.
  • a releasing device for electric switches having, in combination, a bearing member, an abutment member carried by and movable with respect to the bearing member, a fixing member carried by the bearing member and movable with respect to the bearing member and the abutment 15 ing provided with abutments arrangedto cooperate with other corresponding portions of the thermal releasing elements, the thermal releasing elements being so disposed as to become deformed diiferentlybetween the first-named and the second-named portions, means for heating the thermal releasing elements individually, thereby to efi'ect actuation of the abutment member in response-to the'deformations of the thermal ref leasing elem-ents, and means for releasing a Aswitch in response to the actuation of the abutment member.
  • a releasing device for electric switches having, in combination, a housing, an abutment member and a fixing member movably disposed in the housing and movable with respect to each other, a plurality of substantially identical bimetallic strips disposedin the housing and connected with the fixing member at corresponding portions of the bimetallic strips, the abutment member being provided with abutments arranged to cooperate with other corresponding portions of the bimetallic strips, the bimetallic strips being so disposed as to bend between the first-named and the second-named portions, thereby to effect f actuation of the abutment member in response to the deformations of the bimetallic strips, and means for releasing a switch in response to the actuation of the abutment member.
  • a releasing device for electric switches having, in combination, a bearing member, an abutment member carried by and movable with respect to the bearing member, means for normally maintaining the abutment member yieldingly in a normal position, a fixing member carried b'y the bearing member and movable with respect to the bearing member and the abutment member, a stop for limiting the movement of the xing member in one direction relative to the abutment member, a plurality of 'substantially identical thermal releasing 'elements connected with the fixing member at corresponding portions of the thermal releasing elements, the thermal releasing elements being adapted to be subjected to deformation under heat, the abutment member being provided with.
  • thermal re leasing elements being so disposed as to become A deformed differently between the first-named and the second-named portions, means for heating the thermal releasing elements individually, thereby to effect actuation of the abutment member away from the normal position in response to the deformations of the thermal releasing elements in opposition to the action of the yielding -maintaining means-'and means for releasing a switch in response tothe actuation of the abutment member.
  • A'releasing device for electric switches having, in combination. a bearing member, an abutment member carried by and movablewith respect to the bearing member, a xing member carried by the bearing member and movable with respect to the bearing member and the abutment member, a plurality of substantially identical thermal releasing elements connected with the fixing member at corresponding portions of, the thermal releasing elements, the .thermal releas-l tionary cooperating abutments, one corresponding to each abutment-member abutment, means for normally clamping each thermal releasing element yieldingly between one of the stationary abutments and the corresponding abutmentmember abutment, the thermal releasing elements being so disposed as to become deformed differently between the first-named and the second-named portions, means for heating the thermal releasing elements individually, thereby to effect actuation of the abutment member in response to the deformations of the thermal releasing elements. and means for releasing a switch in response to the actuation of the abut
  • a releasing device for electric switches having, in combination, a bearing member, an abutment member carried by and movable with respect to the bearing member, means movably maintaining the abutment member yieldingly in a normal position, a fixing member carried by the bearing member and movable with respect to the bearing member and the abutment member, a stop for limiting the movement of the fixing member in one direction relative to the abutment member, a plurality of substantially identical thermal releasing elements connected withA the fixing member atl corresponding portions of the thermal releasing elements, the thermal releasing elements being adapted to be subjected to deformation under heat, the abutment member being provided with abutments arranged to cooperate with other corresponding portions of the thermal releasing elements, a plurality of stationary cooperating abutments, one corresponding to each abutment-member abutment, means for normally clamping each thermal releasing element yieldingly between one of the stationary abuments and the corresponding abutmentmember abutment, the thermal releasing ve
  • a releasing device for electric switches having, in combination, a housing, an abutment and axing member movably disposed in the housing and movable with respect to each other, a plurality of substantially identical bimetallic strips disposed in the housing and connected with the fixing member at corresponding portions of the bimetallic strips, means for normally maintaining the abutment member yieldingly in a normal position, a stop for limiting the movement of the fixing member in one direction, the abutment member being provided with abutments arranged 'to cooperate with, other corresponding portions of the bimetallic strips, a plurality of stationary cooperating abutments, one corresponding to each abutment-member abutment, means for normally clamping each bimetallic stop yieldingly between one of the stationary'abutments and the-corresponding abutment-member abutment, the bimetallic strips being so disposed as to bend between the ilrstnamed and the second-named portions, means for heating the bimetallic strips individually, thereby to effect
  • a releasing device for electric switches having, in combination, a movable abutment member, a fixing member movable with respect 4to the abutment member, a plurality of substantically identical thermal releasing elements connected with the fixing member at corresponding portions of the thermal releasing elements, the thermal releasing elements being adapted to be subjected to deformation under heat, the abutment member being provided with abutments disposed normally to engage other corresponding portions of the thermal releasing elements at one side of each releasing element, a plurality of stationary abutments, one corresponding to each abutment-member abutment disposed normally to engage the said other portions ofthe thermal releasing elements at the other sides of the respective releasing elements, means normally ⁇ clamping each thermal releasing element yieldingly between one of the stationary abutments and the corresponding abutment-member abutment, the thermal releasing elements beingso disposed as to become deformed differently between the first-named and the second-named portions, means for heating said thermal releasing elements
  • a releasing device for electric switches having, in combination, a movable abutment member, a fixing member movable with respect to the abutment member, a stop for limiting the movement of the fixing member in one direction relative to the abutment member, a plurality of substantially identical bimetallic strips connected with the-fixing member at corresponding portions of the bimetallic strips, the abutment member being provided with abutments disposed normally to engage other corresponding portions of the bimetallic strips at one side of each bimetallic strip, a plurality oi' stationary abutments, one corresponding to each abutmentmember abutment, disposed normally to engage the said other portions of the bimetallic strips at the other sides of the respective bimetallic strips, means normally maintaining the abutment member yieldingly in one extreme position of its movement to effect a yielding clamping of each bimetallic strip between one ⁇ of the stationary abutments and the corresponding abutment- 'member abutment, the bimetallic strips being
  • a releasing device for electric switches having, in combination, a movable abutment member, a fixing member movable with respect to the abutment member, a stop for limiting the movement of the fixing member in one direction relative to the abutment member, a plurality of substantially identical thermal releasing elements connected with said fixing member at corresponding portions of the thermal releasing elements, the thermal releasing elements being adaptedgto ,be subjected to deformation under heat, the.
  • abutment member being provided with abutments arranged normally to engage other corresponding portions of the thermal releasing elements at one side of each releasing element, means normally maintaining the abutment member yieldingly in one extreme position of its movement, the thermal releasing elements being so disposed as to become deformed dierently between the first-named and the second-named portions, means for heating said thermal releasing elements individually, thereby, in response to substantially equal deformations of the thermal releasing elements, to effect actuation first of the fixing member into engagement with the stop and then of the abutment member in opposition /to the action of the yielding maintaining means, and a plurality of stationary abutments, one corresponding to each abutment-member abutment, disposed normally to be engaged by the respective thermal releasing elements at the other side of the respective thermal releasing elements, one
  • thermal releasing elements being adapted, in response to substantially unequal deformations only of the thermal releasing elements, to effect actuation of the abutment member only, in opposition to the action of the yielding maintaining means while the remaining undeformed thermal releasing element or elements are, maintained in engagement with its corre- .sponding stationary abutment member or members, and means for releasing a switch in response to the said actuation of the abutment member.
  • a releasing device for electric switches hav-- engage other corresponding portions of the thermal releasing elements at one side oi.' each releasing element, means for normally maintaining the second shaft yieldingly in one extreme position of its movement, the bimetallic releasing elements being disposed so as to bend between the first-named and the second-named portions, heating windings respectively disposedA on Ithe concave sides of the bimetallic releasing elements for heating the bimetallic releasing elements individually, thereby, in' response to substantially equal deformations of the bimetallic releasing elements, to effect rotatable actuation first of the first-named shaft into engagement with the stop and then of the second-named shaft in opposition to the action of the yielding maintaining means, and a plurality of stationary abutments, one corresponding to each of the firstnamed abutments, disposed normally to be engaged by the respective bimetallic releasing elements at the other side of the respective bimetallic releasing elements, one or more of the bimetallic releasing elements being adapted, in
  • a releasing device for electric switches having, in combination, amovable abutment member, a fixing member movable with respect to the abutment member, a stop for limiting the movement of the fixing member in one direction relative to the abutment member,A a plurality of substantially identical thermal releasing elements connected with the fixing member at corresponding portions of the thermal releasing elements,
  • the thermal releasing elements being adapted to be subjected to deformation under heat
  • the abutment. member being provided with abutments arranged normally to engage other corresponding portions of the thermal releasing elements at one side of each releasing element, a plurality of further abutments, one corresponding to each abutment-member abutment, disposed normally to engage the said other portions of the thermal releasing elements at the other sides of the respective thermal releasing elements, means normally maintaining the abutment member yieldingly in one extreme position of its movement to effect a yielding clamping of each thermal releasing element between one ofthe further abutments and the corresponding abutment-member abutment, the thermal releasing elements being so disposed as to become deformed differently between the first-named and the second-named portions, means for heating the thermal releasing elements individually, thereby.
  • the thermal releasing elements in response to substantially equal deformations of ,the thermal releasing elements, to effect actuation first of the xing member into engagement with the stop and then-of the abutment member in opposition to the action of theyielding maintaining means, one or more of the thermal releasing elementsv being adapted, in're- 4sponse to substantially unequal deformations only, of the thermal releasing elements, to effect actuation of the abutment member only inopposition to the action of the yielding maintaining means, and a latch operable in response to the actuation of the abutment member to release a switch.
  • a releasing device for electric switches having, in combination, a rotatable shaft, a stop for limiting the rotative movement of the shaft inA one direction, a plurality of substantially identical bimetallic releasing elements connected with the shaft at corresponding portions of the bimetallic releasing elements, a second rotatable shaft provided with abutments arranged normally to engage other corresponding portions oi the thermal releasing elements at one side of each releasing element, means for normally maintaining the second shaft yleldlngly in one'extreme position of its movement, the bimetallic releasing elements being disposed so as to bend between the first-named and the second-named portions, means for heating the bimetallic releasing elements individually, thereby, in response to substantially equal deformations of the bimetallic releasing elements to effect rotatable actuation first of the first-named shaft into engagement with the stop and then of the second-named shaft in opposition to the action of the yielding maintaining means.

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US186673A 1937-08-20 1938-01-24 Releasing device for electric switches Expired - Lifetime US2199477A (en)

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Application Number Priority Date Filing Date Title
DE2199477X 1937-08-20
DE221442X 1940-09-19

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US (1) US2199477A (enrdf_load_stackoverflow)
BE (1) BE443183A (enrdf_load_stackoverflow)
CH (1) CH221442A (enrdf_load_stackoverflow)
FR (1) FR876543A (enrdf_load_stackoverflow)
GB (2) GB498325A (enrdf_load_stackoverflow)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2494346A (en) * 1947-07-17 1950-01-10 Gen Electric Overload protective device
US2527907A (en) * 1947-02-19 1950-10-31 Crabtree & Co Ltd J A Automatic circuit breaker having thermal overload release units
US2581882A (en) * 1948-07-27 1952-01-08 Cutler Hammer Inc Device for protecting polyphase circuits
US2749407A (en) * 1953-10-15 1956-06-05 Electrical Apparatus Co Ltd Single phasing preventor
DE1025497B (de) * 1954-12-29 1958-03-06 Siemens Ag Thermisches UEberstromrelais, insbesondere Schutzrelais gegen Einphasenlauf von Motoren
DE1034252B (de) * 1954-12-29 1958-07-17 Siemens Ag Thermisches UEberstromrelais, insbesondere Schutzrelais gegen Einphasenlauf von Motoren
US2961517A (en) * 1957-09-16 1960-11-22 Crabtree & Co Ltd J A Thermal overload protection devices for motor starting switches
DE975370C (de) * 1942-08-17 1961-11-16 Siemens Ag Bimetallrelais zur UEberwachung von Mehrphasenverbrauchern
US3161733A (en) * 1961-11-01 1964-12-15 Sylvania Electric Prod Capacitance shorting switch for electrical translating devices
US3315054A (en) * 1965-06-28 1967-04-18 Fed Pacific Electric Co Overload relay with snap-acting condition responsive switch
US3544941A (en) * 1967-11-27 1970-12-01 Starkstrom Schaltgeratefabrik Thermal relay

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB641269A (en) * 1947-08-02 1950-08-09 Ega Electric Ltd Improvements in or relating to electric switch gear
US2866035A (en) * 1955-02-17 1958-12-23 C T Electrical Controls Ltd Thermally operated electric switching mechanisms
US3792401A (en) * 1972-06-29 1974-02-12 Westinghouse Electric Corp Thermally responsive electrical device

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE975370C (de) * 1942-08-17 1961-11-16 Siemens Ag Bimetallrelais zur UEberwachung von Mehrphasenverbrauchern
US2527907A (en) * 1947-02-19 1950-10-31 Crabtree & Co Ltd J A Automatic circuit breaker having thermal overload release units
US2494346A (en) * 1947-07-17 1950-01-10 Gen Electric Overload protective device
US2581882A (en) * 1948-07-27 1952-01-08 Cutler Hammer Inc Device for protecting polyphase circuits
US2749407A (en) * 1953-10-15 1956-06-05 Electrical Apparatus Co Ltd Single phasing preventor
DE1025497B (de) * 1954-12-29 1958-03-06 Siemens Ag Thermisches UEberstromrelais, insbesondere Schutzrelais gegen Einphasenlauf von Motoren
DE1034252B (de) * 1954-12-29 1958-07-17 Siemens Ag Thermisches UEberstromrelais, insbesondere Schutzrelais gegen Einphasenlauf von Motoren
US2961517A (en) * 1957-09-16 1960-11-22 Crabtree & Co Ltd J A Thermal overload protection devices for motor starting switches
US3161733A (en) * 1961-11-01 1964-12-15 Sylvania Electric Prod Capacitance shorting switch for electrical translating devices
US3315054A (en) * 1965-06-28 1967-04-18 Fed Pacific Electric Co Overload relay with snap-acting condition responsive switch
US3544941A (en) * 1967-11-27 1970-12-01 Starkstrom Schaltgeratefabrik Thermal relay

Also Published As

Publication number Publication date
CH221442A (de) 1942-05-31
GB498325A (en) 1939-01-06
GB501885A (en) 1939-03-07
BE443183A (enrdf_load_stackoverflow)
FR876543A (fr) 1942-11-09

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