US2737551A - Circuit interrupter - Google Patents

Description

CIRCUIT INTERRUPTER Filed May 8, 1953 4 INVENTORS THOMAS E. CURTIS FIGS JAMES M. deMONTMOLLIN BY M United States Patent CIRCUIT IN TERRUPTER Thomas E. Curtis, Hampton, and James M. de Montmollin, Griffin, Ga., assignors to Southern States Equipment Corporation, a corporation of Georgia Application May 8, 1953, Serial No. 353,742

11 Claims. (Cl. 200-114) This invention relates to circuit interrupters and more particularly to 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 material are 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 expulsion action in known manner. The circuit interrupting action may be accompanied by withdrawal of one end of the fusible element from the fuse tube by means of an ejector element constructed of a low mass and provided with biasing means arranged to effect a rapid withdrawal of the fuse link from the fuse tube. Since the fusible element is commonly broken by means which is manually operable and since fusible elements of high current ratings are difiicult to break by ordinary manual means, a load break cutout is needed which inherently is capable of breaking fusible elements of high current ratings without requiring the operator to apply heavy forces to the mechanism which tend to cause undesired stresses in and movement of the parts.

A principal object of this invention is to provide a load break cutout which inherently is capable of physically breaking heavy fusible elements of high current ratmgs.

Another object of this invention is the provision of a load break cutout which is arranged to afford a substantial mechanical advantage so as to enable the operator to break large fusible elements mechanically without the necessity of applying excessive forces to the device.

Still another object of the invention is to provide a load break cutout having a fuse holder which inherently remains substantially stationary in its service position until after the fusible element is ruptured during a load breaking operation.

The invention in one form as applied to a load break cutout comprises a conducting element pivotally supported by a fuse tube, an ejector element pivotally mounted on the conducting element, a fusible element arranged so as normally to maintain the conducting and ejector elements in their normal positions, and crank means for moving the ejector element out of its normal position relative to the conducting element thereby to break the fusible element and allow the ejector element promptly to withdraw one end of the fusible element from the fuse tube.

For a better understanding of the invention reference may be had to the following description taken in conjunction with the accompanying drawings in which Fig. 1 is a side view of a load break cutout embodying the invention, Fig. 2 is an enlarged view of a portion of the structure shown in Fig. l as seen from underneath with the parts occupying an intermediate position, and in which Fig. 3 is a detailed, enlarged view of a portion of 2,737,551 Patented Mar. 6, 1956 Fig. 1 as seen from the opposite side of the device from that depicted in Fig. 1 with the parts in an intermediate position.

With reference to Fig. l the numeral 1 represents a support arm which at its left-hand end is mounted on a supporting structure (not shown) and which at its righthand end is secured to insulators 2 and 3. Afiixed to the upper end of insulator 2 is a terminal element 4 which is provided with openings 5 and 6 for cooperating with a longitudinally split bolt 7 by which a conductor (not shown) may be secured to the terminal 4. A hood 9 is pivoted at 10 to the terminal 4 for limited rotary movement and is provided with a latching surface 11. A brush contact 12 is also secured to the terminal 4. Latch 11 and contact 12 cooperate with the movable fuse assembly generally designated by the numeral 13 in a manner to be more specifically described hereinafter.

A terminal 14 is aflixed to the lower end of insulator 3 and is provided with a slot 15 which, as shown in Fig. 1, receives one portion of the longitudinally split terminal bolt 16 for connecting the terminal 14 with a circuit conductor (not shown). Terminal 14 is also provided with a pair of spaced extensions 14a between which the contact brush 17 is mounted. The spaced extensions 14a of the terminal element 14 are provided with jaws 18 which cooperate with portions of the fuse assembly 13 in a manner to be described hereinafter.

The fuse assembly 13 comprises a contact element 19 which is provided with a contacting surface 20 for cooperating with the contact brush 12 and is also provided with an upwardly extending latching portion 21 which as indicated in Fig. 1 is engageable with the latching surface 11 of the hood 9. Secured to the upper end of the contact 19 is a cap member 22. If desired, cap member 22 and contact member 19 may be constructed in accordance with the disclosure of our application Serial No. 338,836, filed February 25, 1953, 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 abovereferred-to structure comprising contact member 19 and cap member 22. As is well known in the art, a fusible element is disposed within the fuse tube 23 and is secured to the contact 19 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 27 therein for receiving a switch stick or other operating member. Terminal element 26 is also provided with a pivotal mounting 28 for the conducting element 29 which is provided witha contacting surface 30 for cooperating with the brush contact 17. The conducting element 29 is also provided with a projection 31 which engages a portion 32 of the terminal element 26 when the conducting element 29 is in its normal position. Conducting element 29 is maintained at its normal position by the conductor 24 which is secured to the conducting element 29 by the connector 33 which is screwed into the threaded opening 34 in the conducting element 29 so as to grip the end of conductor 24 against the ridged surface 35 of element 29.

The assembly 13 is pivotally mounted in the jaws 18 by means of a pin 36 which interrelates the conducting element 29 with the trunnions 37 and 38 which in turn are rotatably supported by the jaws 18. Trunnions 37 and 38 are interconnected by an integrally formed oifsetl with a surface 23a of conductingelement '29 whe'n the" parts occupy the positions indicated in Fig"; 1 'Tl'ie -cirmii't' through the cutout comprises-terminal'14, brush contact 17 conduc tin'g'element 29, the-fusible element having the otit'wardlFeXfetidihg per tidmm} Contact 1 9," bfu'sh conta a 1 2} and the: terminal 4.

Upon the' o'ceiinence of a" faiilt or overload c'o'nditioh on the cii'cnit controlled by the'devic'ey'th'efias'ime ele merit' disposed within the fuse tulie 23 melts-the ejec't'or' 40 under the 'aetien of spring 41* promptly withdraws the conductor 24? and parts associated-therewith frointhe ruse-tube 231 is eXTin'g'HiShe'Cl l byeX pulsion action in" known manner. During or immediately after this period the pivo't 28 mo've's" clockwise a'bout-pin 36' as'" a center from the position indicated in-Fig "."l due to the weight' ofthe structure lfi and 't'oth'e biasing action of the brushcon taot 17.' Continuedrotationot 'pivot 28 abotit the pin 36- as a center eventually causes-downward motion of tite -upwardlyprojecting portion 21 'of'. the contact- 1'9 therebyto disengage latching surfacelli Thereafter the whole str'ucture liswing'sin a clockwisedirection about the t'ru'nriions 37 and 38*andpin 3 6.=' Ihthis way an' isolating gap is establis'hed" between the terminals 4' ari'd lm The arrangement above described-isalso-adaptable a'ccording to this invehtionfo'r u'se" as a device for iiiterrupt'in'g'normal load ciirrentjiir e; current whichis in sufficient in mag-nitude"tomelt the fusible element. Inf this connection it-will beobserved thafthe trunnions 3 7" and 38 and ofiset portion-39 are integrally formedwith a rnanl'iallyoperable handle'42 which atits right-hand extremity is provided with'an opening 43' for receiving the laterally projecting portion 44of a switch sticlc' 45; Thus withthe parts occupyingthe positions-shown-in Fig. la downward pull on the switch-stick45 causes the trun-' nions 37 and 38 and the offset portion"3-9 to-move' in' a clockwise directionabout the-pin 36 Since the'olfset portion 39 'is in engagement with the eje'ctof'AO, the" ejector 4 is' forced to rotate in" a'clockwise direction" about thepin 3 6 as viewed in Fig." 15 Thus" a' itensiou forceisapplied to theconductor 24-whichis sufiicienfto break the fusible element disposed witli'imthe fuse tube 23i U on rupture of this element an" arc is drawn" and subsequehtl it extinguished -by expulsion" tic'tioh-indihdwn manner. The breaking of the fusible element takes place" without causingany appreciable-movementof' conducting eIementLZJ or of tub'e 2 3 according to a -featiire of the invention. For 'this rea'soh tlie latching surface ll sn'u'g ly' and securely holds the projectingportion' 21 of the conta'c't 1 9 in" a contact makihg position until ample op portunity" ha's'beenaifo'rded' to rupture the fusiblefele ment with in tube 23 and to extinguish the ar'cd'r'awn therein Thus 4 destructive arcs' between contact surface sible' to easily break-heavy fusibleelements of lar'gecurrenttratin'gs V I It -willb'e"observedthatiwhethertheconductingelement 2 occupies the pesitidnsliown in Figil ofwhether'th'e ejector element 40 and conductihgelement fihave been A 'ng ac is in such a direction as to tend to withdraw conductor 24fromthe-lower-end oftube 23.-

While we have shown and described a particular embodiment of the invention, we do not wish to be limited thereto and intend in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. An electric fuse comprising a fuse tube,. a fusible" element disposed in said tube and havingia por tion-thereof extending out of one end of said tube;- a conducting element movably supported by said tube and'having a normal position with resp'ectthereto, an ejectorelement movably supported by said conductingtelernent and having a normal position with respect thereto, said portion of said fusible element being normally interrelated with said ejector element so as to hold said ejector element in its normal position relative to said conducting'element and engageable with said ejector element for movwith but movable independently ofsaidconducting element and enaggeablewith'said'ejector element for moV-- ing said ejector elementrelative' to" said conducting element thereby to break said fusible element;

2'. An electric fuse comprising a fuse tube, a fusibleelement disposed in said tube and having, a portion thereof extending out of one end ofsa'id tube, a con-' ducting element movably'supported by said tube and having a normal position with respect thereto, an ejector element movably supported by'said conductingfleleinent and having a normal position withrespectthereto, said portion of said fusible element'beingno'rmally interrelated with said conducting'and ejector elements so asto hold: said'con'ductingand ejector elements in their normal positions, and manual means operably related with said ejectorelement and movable independently of 'said conducting, elementfor engaging and moving said ejector element'outofits normal po'sition relative to said conductingelement thereby physically to" break said' fusible element.

3.'A'n' ele'ctric'fuse comprising a fuse tube a fusibleelement in said tube and having a portion thereof extend:- ing out of one end of said tube,'a conductingelement movably supported by said tube and havingfla normal position with respect thereto, an ejector element-pivotally mounted'on said conducting element and having a normal position with respect thereto, biasingmeanstending tomove'saidejector element out of'its normal-position,

connector means for securing said portionof-saidfusible elementto said conducting element so as to maintain said conducting element-in its normalpositionpsaid"portionof' said fusible element normally being in engagementwith said ejector element so as :normally-to hold said ejector element in its normal position: relative to said element disposed withinsaid tube-and having one end+ thereof secured therein and-havingtheother end thereof extending, out of one end of said-tube; a conducting element'secured by pivotal-support means to said tubeand having anormal position=with respect to s'aid tubeian ejector element'pivotally supported by saidcb'nd'ucting element and having a normal position with res ect thereto, connector means for securing said other-"end of said fusible element to said conducting element thereby to hold said conducting and ejector elements" in their normal} positions, and manual means" interrelated hy, pivotal mounting means with said'cohduc'ting element and enga'g'eable' with said'ejector element for moving,,said ejectorelementout of its normal position relativeflto-s'aid conducting element and tube thereby physically to break said fusible element.

5. 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 pivot means to said tube and having a normal position with respect to said tube, an ejector element secured by pivot means to said conducting element and having a normal position with respect thereto, said portion of said fusible element being interrelated with said conducting and ejector elements so as normally to hold said conducting and ejector elements in their normal positions, a trunnion pivotally connected with said conducting element and constituting a fixed pivot therefor, an offset portion movable with said trunnion and engageable with said ejector element for moving said ejector element relative to said conducting element thereby to break said fusible element, and manually operable crank means movable with said trunnion and offset portion for imparting rotary movement thereto thereby to impart operating movement to said ejector element.

6. An electric fuse comprising a fuse tube, a fusible element disposed in said tube and having a portion thereof extending out of one end of said tube, a movable conducting element having a normal position relative to said tube, a movable ejector element having a normal position relative to said tube, said portion of said fusible element being normally interrelated with said ejector element so as to hold said ejector element in its normal position relative to said tube, a pair of spaced trunnions interrelated with said conducting element by a pivotal connection and interconnected by an offset portion disposed astride said ejector element and engageable there with, and crank means for rotating said trunnions and offset portion to move said ejector element out of its normal position thereby to break said fusible element.

7. An electric fuse comprising a fuse tube, a fusible element disposed in said tube and having a portion thereof extending out of one end of said tube, a movable ejector element having a normal position relative to said tube, said portion of said fusible element being normally interrelated with said ejector element so as to hold said ejector element in its normal position relative to said tube, a pair of spaced trunnions interrelated with said ejector element by a pivotal connection and interconnected by an offset portion disposed astride said ejector element and engageable therewith, and crank means for rotating said trunnions and offset portion to move said ejector element out of its normal position thereby to break said fusible element.

8 An electric fuse comprising a fuse tube, a fusible element disposed in said tube and having a portion thereof extending out of one end of said tube, a movable con ducting element having a normal position relative to said tube, a movable ejector element having a normal position relative to said tube, said portion of said fusible element being normally inner-related with said ejector clement so as to hold said ejector element in its normal position relative to said tube, a pair of spaced trunnions interrelated With said conducting and ejector elements by a pivotal connection and interconnected by an offset portion disposed astride said ejector element and engageable therewith, and crank means for rotating said trunnions and offset portion to move said ejector element out of its normal position thereby to break said fusible element.

9. An electric fuse comprising a fuse tube, a fusible element disposed in said tube and having a portion thereof extending out of one end of said tube, a movable conducting element having a normal position relative to said tube, a movable ejector element having a normal position relative to said tube, said portion of said fusible element being normally interrelated with said ejector ele ment so as to hold said ejector element in its normal position relative to said tube, a pair of spaced trunnions interrelated with said conducting element by a pivotal connection and interconnected by an offset portion disposed astride said ejector element and engageable therewith, biasing means tending to move said ejector element out of its normal position against the action of said portion of said fusible element, and crank means for rotating said trunnions and offset portion to move said ejector element out of its normal position thereby to break said fusible element.

10. An electric fuse comprising a fuse tube, a fusible clement disposed in said tube and having a portion thereextending out of one end of said tube, a movable ejector element having a normal position relative to said tube, said portion of said fusible element being normally interrelated with said ejector element so as to hold said ejector element in its normal position relative to said tube, a pair of spaced trunnions interrelated with said ejector element by a pivotal connection and interconnected by an offset portion disposed astride said ejector element and engage able therewith, biasing means tending to move said ejector element out of its normal position against the action of said portion of said fusible element, and crank means for rotating said trunnions and offset portion to move said ejector element out of its normal position thereby to reak said fusible element.

11. An electric fuse comprising a fuse tube, a fusible element disposed in said tube and having a portion thereof extending out of one end of said tube, a movable conducting element having a normal position relative to said tube, a movable ejector element having a normal position relative to said tube, said portion of said fusible element being normally interrelated with said ejector element so as to hold said ejector element in its normal position relative to said tube, a pair of spaced trunnions interrelated with said conducting and ejector elements by a pivotal connection and interconnected by an offset portion disposed astride said ejector element and engageable therewith, biasing means tending to move said ejector element out of its normal position against the action of said portion of said fusible element, and crank means for rotating said trunnions and offset portion to move said ejector element out of its normal position thereby to break said fusible element.

References Cited in the file of this patent UNITED STATES PATENTS 2,179,749 MeCluskey et a1 Nov. 14, 1939 2,216,843 Johnson Oct. 8, 1940 2,269,130 Schultz Jan. 6, 1942 2,310,466 Schultz et al. Feb. 9, 1943 2,313,365 Schultz Mar. 9, 1943 2,324,114 Schultz et al. July 13, 1943 2,362,314 Schultz et al. Nov. 7, 1944 2,378,109 Schultz Jan. 12, 1945 2,458,742 Schultz Jan. 11, 1949 2,493,432 Yonkers Jan. 3, 1950 2,514,163 Pittman July 4, 1950 2,550,444 Bennett et al. Apr. 24, 1951 2,625,623 Baskerville Jan. 13, 1953 2,680,171 Curtis et al. Jan. 1, 1954

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