US2680171A - Circuit interrupter - Google Patents

Description

J1me 1954 T. E. CURTIS ET 51. 2,680,171

CIRCUIT INTERRUPTER Filed Apri1'6, 1953 THOMAS E. CURTIS HARLOWE. LICHTWARDT INVENTORS ATT NEY Patented June 1, 1954 2,680,171 CIRCUIT INTERRUPTER Thomas E. Curtis and Harlow Hampton, Ga.,

E. Lichtwal'dt,

assignors to Southern States Equipment Corporation, a corporation of Georgia Application April 6, 1953, Serial No. 347,122 16 Claims. (Cl. 200 -114) This invention" relates to circuit interrupters and more particularlyto interrupters of the type commonly referred to as load break cutouts or fuses.

Electric cutouts which incorporate a fusible element disposed within a fuse tube of insulating materialare adapted. for interrupting overload or fault currents by expulsion action in response to the melting of the fusible element and, if. desired, load currents may be interrupted by physically breaking the fusible element thereby to draw an are within the fuse tube which is extinguished by'ex pulsion action in known manner. The circuit interruptingaction may be accompanied by withdrawal of one end of the fusible element from the fuse tube by means of provided with biasing a rapid withdrawal of tube.

Power fuses and; cutouts which are providedwith a pair of contacts respectively mounted at each end of the fuse tubeand interconnected by a fusible element disposed within the tube are arranged so that the contacts are respectively engageabie with a pair of spacedterminals forming. a part of the circuit protected by the fuse or cutout. When the fusible clement is'ruptured due either to fault or overload current orto the application of a physical force thereto, the are drawn must be extinguished before the cutout-or fuse drops out; i. (2., before one of the contacts on the fuse tube separates from its associated terminal in order to prevent the drawing of an arc between such contact and terminal.

A principal object of this invention is the provision f an improved load break cutout which is simple in construction and which-is characterized by a'high degree ofuniformity of operation whether interrupting its controlled circuit under fault or normal load conditions.

Another object-of this invention is to provide means arranged to eilect the fuse link from the fuse Still another object of this invention is the provision of an improvedload break fuse or cutout which is arranged to afford ample opportunity for extinguishment or an are drawn Within the fuse tube before the device drops out to establish inknownmanner a wide gap in the controlled circuitand to relieve the device of severe voltage'stresses.

The invention in one form as applied to a load break cutout comprises aconducting. element pivotallysupported by a fuse tube; an

ejector element pivotaliy mounted on the conducting element, a fusible element arranged so as normally to maintain the conducting and ejector elements in their normal positions, and handle means for moving the conducting and ejector elements out of their normal positions thereby to break the fusible element and allow the ejector element promptly to withdraw one end ofthe fusible elementfrom the fuse tube.

. In accordance with one feature of the invention tion of aportion of the'structure shown in Fig. l, and in which Fig. 3 is a detailed view of a portion of Figs. 1 and 2.

With reference to Fig. 1- the numeral l represents a support arm which at its left-hand end is mounted on a supporting structure (not shown) and. which at itsright-hand end is secured to insulators 2 and 3. Affixed to the upper end of insulator 2 is a terminal element 4 which is provided with openings 5 and 5 for cooperating with a longitudinally split bolt "1 by which a conductor (not shown) may be secured to the terminal 4. Also formed in the terminal i is an which may be used in any desired manner to the terminal a for limited rotary movement and is provided with a latching surface H. A brush contact I2 is also secured to the terminal s. Latch and contact i2 cooperate with the movable fuse assembly generally designated by the numeral is ina manner to be more specifically described hereinafter.

A terminal M is affixed to the lower end of insulator 3- and is provided with a slot t5 which; as shown in Fig.1. receives one portion of the longitudinally split terminal bolt Iii for connecting the terminal- [4 with a circuit conductor (not shown). Terminal M is also provided with a pair of spaced extensions Ma between which the contact'brush W- is mounted The-spaced extem sions Me of the terminal element M are provided with jaws 18 which cooperate with portions of the fuse assembly i3 in a manner to be described hereinafter.

The fuse assembly [3 comprises a contact element l9 which is provided with a contacting surface 29 for cooperating with the contact brush l2 and is also provided with an upwardly extending latching portion 2| which as indicated in Fig. l is engageable with the latching surface H of the hood 9. Secured to the upper end of the contact i9 is a cap member 22. If desired, cap member 22 and contact member l9 may be constructed in accordance with the disclosure of application Serial No. 338,836 filed February 25, 1953, by Thomas E. Curtis and James M. deMontmollin and assigned to the assignee of this invention. It will be understood that insofar as the principles of this invention are concerned any known assembly arrangement could be used instead of the above referred to structure generally designated by the numeral 19 in Fig. 1. As is well known in the art, a fusible element is disposed within the fuse tube 23 and is secured to the contact l9 at its upper end and provided with a projecting portion 24 which extends out of the lower end of the fuse tube 23.

Afiixed to the fuse tube 23 by means of the screw 25 is a terminal element 26 which is provided with an opening 21 therein for receiving a switch stick or other operating member. Terminal element 26 is also provided with a pivotal mounting 23 for the conducting element 29 which is provided with a contacting surface 33 for operating with the brush contact IT. The con ducting element 29 is also provided with a shoulder 3| which engages a portion 32 formed in the left-hand extremity of the terminal element 26. Normally the shoulder 3| of the conducting element 29 engages the projection 32 of the terminal element 26 as is indicated in Fig. 1. Also formed integrally with the conducting element'29 is a pair of trunnions 33 which respectively engage the jaws l8 formed in the extensions l4a. of the terminal element [4, the jaws l8 and trunnions 33 constituting a fixed pivot.

Pivotally mounted at 34 on the conducting element 29 is the ejector element 35. The pivot 34 for the ejector 35 coincides with the center of rotation of the trunnions 33. provided with an upwardly extending portion 36 which is arranged to engage a projection 31 formed in the conducting element 29. Thus counterclockwise rotation of ejector element 35 about its pivot 34 is prevented when the upwardly extending shoulder portion 36 engages the projecting portion 31 of conducting element 29. Ejector element 35 is biased for rotation in the clockwise direction about its center of rotation 34 by means of the coiled spring 38. Also mounted by a threaded engagement on the conducting element 29 is the connector means 39 which secures the end of the conductor 24 in position on the conductin element 29 as best shown in Fig. 2. Thus by means of the fusible element and the extension 24 thereof the conducting element 29 and ejector element 35 are maintained in their normal or solid line positions as indicated in Fig. 1 so that normally a circuit is complete through the device. Such a circuit comprises the terminal M, the brush contact l1, conducting element 29, fusible element 24, contact [9, the brush contact l2, and the terminal 4.

Upon the occurrence of a fault or overload Ejector 35 is condition on the circuit controlled by the device, the fusible element disposed within the fuse tube 23 melts and the ejector 35 promptly withdraws the conductor 24 and parts associated therewith from the lower end of the fuse tube 23. The are drawn within the fuse tube 23 is extinguished by expulsion action in known manner. During this period the pivot 28 moves from the position indicated by the numeral 28 to the position indicated in Fig. 2 by the numeral 28 due to the weight of the structure 13 and to the biasing action of the brush contact 11. Continued rotation of pivot 28 about the trunnions 33 as a center eventually causes downward motion of the upwardly projecting portion 21 of the contact l9 thereby to disengage latching surface l I. Thereafter the whole structure l3 swings in a clockwise direction about the trunnions 33. In this way an isolating gap is established between the terminals 4 and I4.

The arrangement above described is also adaptable for use as a device for interrupting normal load current; i. e., current which is insufficient in magnitude to melt the fusible element. In this connection it will be observed that the conducting element 29 is provided with a manually operable handle 49 which at its righthand extremity is provided with an opening 4| for receiving the laterally projecting portion 42 of a switch stick 43. Thus with the parts occupying the positions shown in Fig. l a downward pull on the switch stick 43 causes the pivot 28 to move in a clockwise direction about the center 33. Since the shoulder 36 of the ejector 35 is in engagement with the stop 31 on conducting element 29, the ejector 35 cannot rotate in a counterclockwise direction about its center 34. Thus a tension force is applied to the conductor 24 which is sufficient to break the fusible element disposed within the fuse tube 23. Upon rupture of this element an arc is drawn and subsequently extinguished by expulsion action in known manner. From Fig. 1 it will be observed that the axis of tube 23 is spaced closer to the center of rotation comprising the trunnions 33 when the parts are in their normal position than is the pivot 28 and that the lower end of tube 23 is normally closer to fixed pivot 33 than to the pivot 28. Thus substantial arcuate movement of pivot 28 through dead center and beyond with respect to the pivot 33 can be effected along with transverse movement to the right of tube 23 before any appreciable movement of the tube 23 in an axial direction thereof takes place. For this reason the latching surface ll snugly engages and securely holds the projecting portion 21 of the contact 19 in a contact-making position until ample opportunity has been afforded to rupture the fusible element within tube 23 and to extinguish the are drawn therein. Thus destructive arcs between contact surface 20 and brush contact l2 are prevented.

It will be observed that whether the conducting element 29 occupies the position shown in Fig. 1 or whether the ejector element and conducting element 29 have been moved to the position indicated in Fig. 2, the biasing action of spring 38 tending to rotate the ejector element 35 is the same. Thus substantially uniform ejecting action is accomplished whether the device is being operated as an overload or fault responsive device or whether the device is being operated as a load break device.

While we have shown and described a particular embodiment of the invention, we do not wisliztobeJimited theretoand= intend' in:--therap pended claims: to cover allfl such changes and modifications as af'alhwithin the :true spirituand I scope; of 'the invention:

What-We claim asnew and desirezto -secure by' 5 Letters P'atent of the 4 United states :is:

1 An electric fuse comprising a--,fusetube*, a. fusible element: secured: with-in said tube. and. having: a. portion: thereot extending out; of": one end of. said tube, a-conducting element movab-ly" supported by saiditubeiancl :having -aL-norma1ij'po.v-- sition' with=- respecta thereto; arr ejector: elements movably: supported by: said: conducting element and"h'avingaa normal positionzwitha respect there: toiwfrom which: said: ejector: is: movablesin only one.-dir.ection,;.said;portion; of. :said fusible elementi bein'gmormally interrelatedwith"saidejector elee mentwso :as to hold. said. ejector element. in its normalsposition relativetto saidyconductingj alement, and manualiimeans-ion-moving. ,said :con-v ducting element out. of: its:..normal position Without moving said ejector J element relativesitosaid. conducting: element. thereby; physically to break saidqfusible elements 2sAn5electric-fuse;comprisingasfuse tube, a

fusible. element securely; mounted within said tube and having a portion thereof extending: out ofgone: end of. said'tube, a: conducting, element, movably supportedby; said..,tube.and having a normal positionwith respect .thereto, an ejector elementimova-bly supported by said conducting; element and havinganormal position with respectuthereto from whichiasaidejector is movable in -,only;one-direction,psaid, portion of said fusible elementnbeing;normally interrelated with said. ejector. elementssoias to holdssaid ejector element. in its normal. position relative. to said conducting element, and a handle movable with said conducting elementifor applyinga force thereto sufiicient.,.to. break said fusible element.

electric fuse comprising aefuse ,tube, a fuse link-havingafirst portions thereof securely affixediwithin said .tube andhaving a second portion thereof extending out, of oneendof said tube, s a conductingelement"movably supported by said tube and having .a ,normalposition with respect. thereto an ejector element movably supported by said conducting elementand having a normal? position .withhrespect. thereto from which said ondiportion of saidfuse link being normallyinten relatedwithsaid conducting and ejector elementsv soasto hold saidconducting and ejector elements intheirnormal positions, and manual means for moving said'conducting element out of its nor- 5:

mail positionwithout moving said ejector element relative. to said conductingielement' thereby physically tosbreak said fuse link;

4; Anflelectric fuse comprisinga fusetube, a fuse link havinga first affixed withinsaid tube and having a second por tion thereofextending out of'one end of said tube; a conductin'g'element movably; supportedibysaid tube and having a normalposition with respect' thereto; an ejector element-m'ovablysup 651 ported by said conducting element and having a normalposition in" engagement with apart of" said conducting'element thereby to *preventmove ment of said ejector element relative 'to' said-com ducting aelementin onedirection biasingmeans tending to move-said ejector element in another direction out" of its normal position; connector means-forssecuring said second portion-of said fusevlink to said conducting: element: so as to maintaimsaid-conducting element; in'zits normahv ejector. s movable in, only onedirection, said secportion thereof securely 0.

position said-2i second portion: of?" said fusealink: normally: being in engagementwith' -saiclg ejectorelement so: as -normally tor-hold: saidfieje'cton ele:- ment in its normal position relative to saidlconaducting element; and fmanuaI meansfQr: moving-:9: said conducting elementout of itszn'or-mal posit-. tion without' moving said i'ej ector *elementu'elatives to'said conducting element athereby physicallyte; break said fuse link.

An: electric :fusei: comprising aifusetube; a fusib1e-:-- element disposed within said; tube'se. and?v havingron'eiendf thereof secured thereinzandzhav ing the other endithereof extending outxofi'orree" emt 'off said; tube; a conducting; element :securedi: hiy -pivotal support meansztorsaiditube andliavings, a-- normal position with: respect :to saidL'tub'e: an: ejector elementpivotally:supported by said-Econ ducting elementsand: having a normal positiom with respect thereto said ejector. element shavings? awshoulder engageable rwithzaportion of 'said"c0nducting element to prevent rotation thereof: 1m: onedirection' from-its normal' position, connector-z: meansfor secu-ring'said otheriend of said fusible element:v to; said conducting element therebyto ihold saidconducting-and: ejector elements in their: normal positions, and manual: means operablyrelated "with" said conducting element-for 1 moving; said! conducting element out Jof its hermal posie tion without moving said 'ejectorelement-relative: to said'conducting element thereby physically to breaki said fusible: element;

6; Anelectric fuse comprising -a:fuse-tub'e;: a fusible element disposed withinsaid tube and? having a: portion thereof extending out of'one end 'ofsaid tube, a conducting:element securedbw apivot means to saidtube andhaving aanormalli position with respect -to saidtube; a fiXedpivot about vvhich said conducting element-is rotatable; said-portion of said fusible--element being inter related With-said-conducting element so as-normally to holdsaid conducting element in its normal: position, said pivots being-normally dis posed: with respect to said tube so that predetermined movement of said conducting element; ab'out said pivots imparts substantial" transverse movement to said tube in: a direction away-fromsaid fixed pivot before causing substantial? axial; movement thereof.

7. An electric fuse comprising a fuse tube; a fusible-element .havingwne-end thereof secured within said tube and having 'a' portionth'ereof ex tending'out of one :end 'of saidftube'; a conductin'g; element secured by'a pivot means to said tube and" having a-normal position with "respect tosaid tube, a fixed pivot about which said conducting element isrotatable; said portion of said-"fusible: element being interrelated with said conducting element so as normally to 'hold said conducting element in itsnorm'al position, said pivots" being: normally disposed with respect to' said-tubesm that predetermined movement -of-sai'd'- conducting element about said pivots imparts substan tial transverse: movement to said tube 7 before" causing substantial axial movementthereof and manually operabl'e means for'impartin'g operating movement to" said conducting element:

81 An" electric fuse comprising a: fuse-tube; a fusible element" disposed within said tube" and having a portion thereof extending outiof one end of saidtube; aconductingelement secured by a first pivot means to saidtube and h'aving a normal'posit'ion with respect to said tube; a-fiice'd-'-' pivot about which said conducting elementi'isa rotatable; said portion of said fusible element ib'eingq interrelated with: said I conducting-ielement so ass normally to hold said conducting element in its normal position, said fixed pivot being closer to the axis of said tube and to said one end thereof than said first pivotwhen said conducting element is in its normal position so that predetermined movement of said conducting element about said pivots imparts substantial transverse movement to said tube before causing substan tial axial movement thereof.

9. An electric fuse comprising a fuse tube, a fusible element disposed within said tube and having a portion thereof extending out of one end of said tube, a conducting element secured by a first pivot means to said tube and having a normal position with respect to said tube, a fixed pivot about which said conducting element is rotatable, said portion of said fusible element being interrelated with said conducting element so as normally to hold said conducting element in its normal position, said fixed pivot being closer to the axis of said tube and to said one end thereof than said first pivot when said conducting ele.

ment is in its normal position so that predetermined movement of said conducting element about said pivots imparts substantial transverse movement to said tube before causing substantial axial movement thereof, and manually operable means for imparting operating movement to said conducting element.

v 10. An electric fuse comprising a fuse tube, a fusible element having, one end thereof secured within said tube and having a portion thereof extending out of one end of said tube, a conducting element secured by a first pivot means to said tube and having a normal position with respect to said tube, a fixed pivot about which said conducting element is rotatable, connector means for securing said portion of said fusible element to said conducting element so as to hold said conducting element in its normal position, said fixed pivot being closer to the axis of said tube and to said one end thereof than said first pivot when said conducting element is in its normal position, and a handle movable with said conducting element for simultaneously rotating said conducting element about said first and said fixed pivots so as to increase the distance between said fixed pivot and said tube thereby to break said fusible element.

; 11. An electric fuse comprising a fuse tube, a fusible element secured within said tube and having a portion thereof extending out of one end of said tube, a conducting element secured by a first pivot means to said tube and having a normal position with respect to said tube, a fixed pivot about which said conducting element is rotatable, connector means for securing said portion of said fusible element to said conducting element so as to hold said conducting element in its normal position, said fixed pivot being closer to the axis of said tube and to said one end thereof than said first pivot when said conducting element is in its normal position, and a handle movable with said conducting element for simultaneously rotating said conducting element about said first and said fixed pivots so as initially to increase the distance between said fixed pivot and said tube without imparting appreciable movement to said tube in a direction axially thereof thereby to break said fusible element.

12. An electric fuse comprising a fuse tube, a fusible element secured within said tube and having a portion thereof extending out of one end of said tube, a conducting element secured by a first pivot means to said tube and having a normal position with respect to said tube, a fixed pivot about which said conducting element is rotatable, an ejector element movably supported by said conducting element and having a normal position with respect thereto from which said ejector element is movable in only one direction, said portion of said fusible element being normally interrelated with said conducting and ejector elements so as to hold said conducting and ejector elements in their normal positions, said pivots being normally disposed with respect to said tube so that simultaneous movement of said conducting element about said pivots imparts substantial transverse movement to said tube before causing substantial axial movement thereof, and a handle movable with said conducting element for simultaneously rotating said conducting element about said first and said fixed pivots so as to change the-distance between said fixed pivot and said tube thereby to break said fusible element.

13. An electric fuse comprising a fuse tube, a fusible element secured within said tube and having a portion thereof extending out of one end of said tube, a conducting element secured by a first pivot means to said tube and having a normal position with respect to said tube, a fixed pivot about which said conducting element is rotatable, an ejector element movably supported by said conducting element and having a normal position with respect thereto from which said ejector is movable in only one direction, said portion of said fusible element being normally interrelated with said eonducting and ejector elements so as to hold said conducting and ejector elements in their normal positions, said fixed pivot being closer to the axis of said tube than said first pivot and said pivots being spaced from each other in a direction longitudinally of said tube with said fixed pivot nearer said one end of said tube when said conducting element is in its normal position, and a handle movable with said conducting element for simultaneously rotating said conducting element about said first and said fixed pivots so as initially to increase the distance between said fixed pivot and said tube without imparting appreciable movement to said tube in a direction axially thereof thereby to break said fusible element.

14. An electric fuse comprising a fuse tube, a fusible element secured within said tube and having a portion thereof extending out of one end of said tube, a conducting element secured by a first pivot means to said tube and having a normal position with respect to said tube, a fixed pivot about which said conducting element is rotatable, an ejector element movably supported by said conducting element and having a normal position with respect to said conducting element, connector means for securing said portion of said fusible element to said conducting element so as to hold said conducting element in its normal position, said portion of said fusible element normally being in engagement with said ejector element so as normally to hold said ejector element in its normal position relative to said conducting element, one of said pivots normally being closer to the axis of said tube than the other of said pivots and said pivots normally being disposed longitudinally of said tube so that simultaneous predetermined movement of said conducting member about said pivots causes transverse movement of said tube before causing appreciable axial movement thereof, and a handle movable with said conducting element for simultaneously rotating said conducting element about said first and said fixed pivots so as to change the distance between said tube and one of said pivots thereby to break said fusible element.

15. An electric fuse comprising a fuse tube, a fusible element secured within said tube and having a portion thereof extending out of one end of said tube, a conducting element secured by a first pivot means to said tube and having a normal position with respect to said tube, a fixed pivot about which said conducting element is rotatable, an ejector element movably supported by said conducting element and having a normal position with respect thereto, connector means for securing said portion of said fusible element to said conducting element so as to hold said conducting element in its normal position, said portion of said fusible element normally being in engagement with said ejector element so as normally to hold said ejector element in its normal position relative to said conducting element, said fixed pivot normally being closer to the axis of said tube than said first pivot and said pivots being spaced from each other in a direction longitudinally of said tube when said conducting element is in its normal position, and a handle movable With said conducting element for simultaneously rotating said conducting element about said first and said fixed pivots so as initially to increase the distance between said fixed pivot and said tube without imparting appreciable movement to said tube in a direction axially thereof thereby to break said fusible element.

16. A circuit interrupter comprising a tube of insulating material, a fusible element secured within said tube and having a portion thereof extending out of one end of said tube for interrupting an electric current therethrough by expulsion action, a terminal element aflixed to said tube, a conducting element secured to said terminal element by a first pivot, said conducting element being engageable with a portion of said terminal element to prevent rotation thereof in one direction, said conducting element also being rotatable about a fixed pivot, an ejector element pivotally supported by said conducting element and biased for rotation relative to said conducting element in one direction, said ejector element being engageable with a portion of said conducting element so as to prevent rotation of said ejector in the other direction, means for securing one end of said fusible element to said conducting element so as normally to maintain said ejector in engagement with said conducting element and to hold said conducting element in engagement with said terminal element, said fixed pivot normally being closer to the axis of said tube and to said one end thereof than said first pivot, and manual means for rotating said conducting element about its fixed and first pivots thereby to break said fusible element and establish an arc to be interrupted Within said tube.

References Cited in the file 01 this patent UNITED STATES PATENTS Number Name Date 2,133,139 Hermann Oct. 11, 1938 2,493,432 Yonkers Jan. 3, 1950 2,514,163 Pittman July 4, 1950

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