Patent Publication Number: US-3876849-A

Title: Electric circuit interrupter

Description:
United States Patent 91 Jackson, Jr.  
 [ Apr. 8, 1975 [75] Inventor:  
 [52] US, Cl ..200/163; ZOO/146 R; 200/16 C; ZOO/321; ZOO/323 [51] Int. Cl. I-I0lh 1/38 [58] Field of Search ZOO/146, 163, 16 B, 16 C, 200/151, 321, 323. 290  
 [56] References Cited UNITED STATES PATENTS 2,785,319 3/1957 Simpson et a1 ZOO/163 R 3,259,726 7/1966 Rueffcr 200/151 R Primary Examiner-Robert S. Macon Attorney, Agent, or FirmWalter M. Rodgers [57] ABSTRACT An electric circuit interrupter which is primarily adapted for use in conjunction with an electric fuse or cutout includes a housing structure comprising an inner tubular housing element of insulating material, a pair of outer tubular housing elements of insulating material telescopically mounted respectively about opposite ends of the inner tubular housing element and movable relative to each other and to said inner housing element together with a pair of relatively movable contacts one of which is fixedly mounted relative to one of the outer housing elements. An opening spring is interposed between the inner housing element and the other of said outer elements and biases the contacts toward open circuit condition while a closing spring is interposed between the inner housing element and said one outer housing element and biases the contacts toward closed condition. The closing spring is energized by the opening spring during a contact opening operation. The telescoping elements are interrelated so as normally to exclude moisture due to atmospheric precipitation from the interior of the housing and the housing elements also serve to isolate the conductive parts disposed within the housing from the biasing springs.  
 14 Claims, 9 Drawing Figures szema m PATENTEDAPR 81975 @QQQQ 1 ELECTRIC CIRCUIT INTERRUPTER Auxiliary circuit interrupters for use in conjunction with electric fuses and cutouts are normally connected in parallel circuit relation to a pair of separable contact elements constituting portions of the fuse or cutout and such contacting elements normally are opened initially followed by subsequent opening of the contacts of the auxiliary interrupter, the auxiliary interrupter being well adapted to interrupt and extinguish an electric arc. Such auxiliary interrupters ordinarily must be of compact and unitary construction and for this reason may be arranged so the current to be interrupted is transmitted through a biasing spring which may serve quickly to separate the contacts once a circuit interrupting operation is initiated. In such a device, a series of operations which require a biasing spring to conduct substantial currents may impair the characteristics of the spring. Furthermore it is frequently the practice to construct auxiliary interrupters in such manner that&#39;conducting elements are exposed during a circuit interrupting operation and thus constitute a hazard to the operator. In known auxiliary interrupters, it is sometimes the practice to energize the opening spring and the closing spring manually and simultaneously thus requiring a substantial operating force which must be imparted to the operating elements by an operator usually through the instrumentality of a hook stick.  
  According to the present invention an auxiliary circuit interrupter is provided in which closing an opening springs are shielded from the conducting elements and from atmosphere and in which the conducting parts are fully enclosed. Furthermore, according to the invention, the closing spring is energized by the opening spring during the later stages of a circuit interrupting operation. More specifically an auxiliary interrupter constructed according to one form of the invention may comprise an inner tubular hollow housing element of insulating material about which a pair of outer tubular housing elements formed of insulating material are telescopically disposed with one outer element surrounding one end of the inner housing element and with the other outer element surrounding the other end of the inner element and one contact of a pair of relatively movable contacts is mounted in fixed relation within the inner housing element and the other contact is mounted in fixed relation within one of the outer housing elements. Preferably the telescoping housing elements are constructed and arranged so as to exclude atmospheric precipitation from inside the interrupter housing structure.  
  For a better understanding of the invention reference may be had to the following detailed description taken in conjunction with the accompanying drawings in which FIG. 1 is an overall side view of an electric cutout on which an auxiliary circuit interrupter constructed according to the invention is mounted, the cutout and interrupter being shown in closed circuit condition; FIG. 2 is an enlarged view partially in section of a portion of the apparatus shown in FIG. 1 and taken along the line designated 2-2 in FIG. 1; FIG. 3 is a view similar to FIG. 1 but showing the cutout in its open circuit position; FIG. 4 is a top view of a mounting racket by which the auxiliary interrupter is mounted on the sleet shield of the cutout; FIG. 5 is a side view of FIG. 4 taken along the line designated 5-5 in FIG. 4; FIG. 6 is a side view of the upper portion of the cutout and interrupter depicted in FIGS. 1 and 3 ane which represents the upper contact structure of the interrupter and cutout in partially opened condition; FIG. 7 is a cross-sectional view of the auxiliary interrupter showing the parts in their closed circuit positions; FIG. 8 is a view similar to FIG. 7 but showing the parts in the positions which they occupy after a circuit interrupting operation has been initiated but before contact separation takes place and in which FIG. 9 is a view similar to FIGS. 7 and 8 and which depicts the contacts after separation but before the relatively movable conducting parts have reached their maximum degree of separation.  
  In the drawings the numeral 1 designates a conventional insulator supported by a conventional insulator mounting bracket designated by the numeral 2. Of course mounting bracket 2 is secured to any suitable supporting structure such as a power line pole or cross arm in conventional fashion. Secured atop insulator l is the top hardware structure of a conventional contact generally designated by the numeral 3 on which line terminal 4 is mounted. Bottom hardware structure of the cutout is generally designated by the numeral 5 and is secured to the lower end of insulator 2 in conventional fashion and supports line terminal 6. A fuse holder generally designated by the numeral 7 interconnects the hardware structures 3 and 5 in conventional fashion. An auxiliary interrupter generally designated by the numeral 8 is constructed according to this invention and is mounted by means of mounting band 9 about the housing of interrupter 8 and which in turn is secured to mounting bracket 10 by bolts 11 and 12 as best shown in FIG. 4. Mounting bracket 10 is secured by bolts or rivets 13 to the sleet hood 14 which is of conventional construction. Line terminal 4 is electrically connected with sleet hood 14 and may be formed integrally therewith. Conductor 15 interconnects the upper lefthand terminal of auxiliary interrupter 8 with the mounting bracket 10 by suitable means such as by bolt 11.  
  At the opposite end of the auxiliary interrupter 8 conducting latch 16 is arranged for cooperative engagement with auxiliary contact 17 mounted by means of transverse conducting element 18 to the upper metallic conducting collar 19 of the fuse holder 7. A sleet hood 20 is disposed above contact 16. In parallel with the circuit through the auxiliary interrupter 8 is the sleet hood 14 which is provided with a yieldable contact 21 and a yieldable latch 22 of conventional construction. When the parts are in their closed positions as shown in FIG. 1, the upper contact 23 forming an integral part of collar 19 of the fuse holder is disposed in secure contacting engagement with contact 21 and is held in this position behind the latch 22. Dispostable cap 24 is mounted atop the collar 19 in conventional fashion and a pivotally mounted latch release element 25 is arranged for engagement with a hook stick by way of the aperture 26 formed therein so that downward movement of the right hand end of latch 25 elevates latch 22 and releases the contact 23 so that this contact as well as the auxiliary contact 17 may move toward the right and generally clockwise from the position depicted in FIG. 1 to the fully open position depicted in FIG. 3. The fusible element is not shown but is disposed within the fuse tube 711 and is terminated by fuse link extension 33 to the lower hardware structure 5.  
  Lower tube casting 27 is secured about the lower end of fuse tube 7a and is pivoted at 28 to hinge element 29 provided with trunions 30 rotatable within a pair of spaced apart jaws 31 which form integral portions of conducting element 32 which is secured in known manner to the lower end of insulator 1 and on which terminal 6 is mounted.  
  The fuse link extension 33 is secured as by a thumb screw 34 in secure contact relation to the hinge element 29 in a manner well known in the art.  
  A suitable aperture 35 is formed in lower casting 27 in conventional fashion.  
  For the purpose of relieving the fuse link and its extension 33 from a substantial portion of the weight of the fuse holder 7 and of the bias of contact springs which are conventional construction, the latching element designated by the numeral 36 may be provided. This latch element is pivotally mounted at 37 on the hinge element 29 and is provided with an offset portion 38 which as shown in FIG. 1 is disposed adjacent pin 39 mounted on a pair of spaces ears 40 when the fuseholder is in fused position. This with the parts occupying the positions depicted in FIG. 1, a substantial part of the weight of the fuse holder 7 and of the pressure due to the contact springs is taken by the latch 36.  
  In order to facilitate an opening operation and to aid in ejecting the lower end of the fuse link and of extension 33 from the lower end of the fuse tube 7a, a biasing spring is provided and is designated by the numeral 41 as best shown in FIG. 2. The biasing spring has one end 42 biased against latch 36. Tab 44 on latch 36 contains the leg 42 preventing its slipping off the latch. End portion 43 of biasing spring 41 is captured underneath the portion 46 of hinge 29 so as to urge the latch 36 toward rotation in a clockwise direction as viewed in FIGS. 1 and 3 about its pivot 37.  
  With the parts occupying the positions depicted in FIG. 1, an overload through the device causes the fuse link tomelt and allows the fuse holder and all parts associated therewith including auxiliary contact 17 and transverse conductor 18 to swing in a generally downward and clockwise direction into the position depicted in FIG. 3. Of course such motion is facilitated by rotation of the hinge element 29 about the trunions 30 and is accompanied by rotation of the fuse holder 7 about its pivot 28 and simultaneous rotation of the latch 36 about its pivot 37 so that when the circuit is open the parts occupy the positions depicted in FIG. 3.  
  Should the circuit through the cutout be live, the current flowing in such circuit may be interrupted by the arrangement shown in the drawings by simply inserting a hook stick into the aperture 26 and by then exerting a downward pull thereon. Such an operation releases latch 22 from contact 23 and allows the contact 23 to disengage contact 21 while contact 17 remains in contacting relation with the lower latch contact 16 of the auxiliary interrupter 8. Continued swinging movement of the fuse holder in a generally clockwise direction about the trunions 30 subsequently results in withdrawal of the lower latch contact 16 from the interrupter 8 and subsequently the circuit is interrupted by the auxiliary interrupter 8.  
  The auxiliary interrupter constructed according to this invention is best shown in detail in FIGS. 7, 8 and 9 and comprises housing structure including an inner hollow tubular housing element of insulating material designated by the numeral 50 together with one hollow outer tubular housing. element designated by the numeral 51 and telescopically disposed about the lower end of inner tube together with another hollow outer tubular element constructed of insulating material and designated by the numeral 52 disposed about the upper end of inner tube 50 in telescoping relation therewith. An upper outwardly extending flange element 53 is secured to the upper end of inner tube 50 and a lower flange 54 projects outwardly and is secured to the lower end of inner tube 50. A closure cap 55 is fixedly secured about the upper end of outer insulating tubular element 52 in any suitable manner while a lower closure cap 56 is suitably secured about the lower end of outer housing element 51. An inwardly projecting flange 57 is formed about the lower end of outer housing element 52 while an inwardly projecting flange 58 is integrally formed with the upper end of outer housing element 51.  
  The circuit through the interrupter comprises the lead-in terminal 15, the flexible helical conductor 59 rigidly secured in contacting relation to the contact ferrule 60 on which a plurality of contact fingers 61 are mounted, and the stabber contact 62 having shoulder portion 63 which is gripped when in closed position by the inwardly projecting portions 64 of the contact fingers 61 so as releasably to latch the contacts closed. At its lower end, stabber 62 is connected with conducting latch 16 which as pointed out above is arranged to cooperate with auxiliary contact 17 to complete a circuit from terminal 4 to the upper conducting elements of the fuse holder 7.  
  To aid in effecting rapid separation ofthe contacts 61 and 62, operating biasing means in the form of an opening spring 65 is interposed between flange 53 on inner tube 50 and internal flange 57 formed on external tube 52 and between tubes 50 and 52.  
  For the purpose of reclosing the interrupter conducting parts and for restoring the housing elements to their normal closed positions following a circuit interrupting operation, operating biasing means in the form of a closing spring designated by the numeral 66 is provided and cooperates with the outwardly projecting flange 54 on the lower end of inner tube 50 and the inwardly projecting flange 58 formed at the upper end of outer housing tube 51. Closing spring 66 is captured between tubes 50 and 51. Both springs 65 and 66 are compression type springs and are isolated from the conducting parts and are shielded from atmospheric conditions.  
 Contact latch 16 is provided with a latch surface 67 which cooperates with auxiliary contact 17 and stabber.  
 62 is secured to latch 16 and cap 56 by pin 68. Since cap 56 is secured to outer tube 51, it is apparent that contact 62 is fixed in relation to outer housing element 51. A shoulder 69 is formed in outer tube 52 and is disposed for engagement by flange 53 of tube 50. Furrule 60 is fixed in position relative to tube 50 by virtue of flange 70 which is integral with inner tube 50 and which is captured between flanges 71 and 72 on ferrule 60. Stabber 62 is surrounded by gas emitting elements 73 and gas is exhausted through ports 74 in cap 56.  
  In order to effect a circuit interrupting operation via the auxiliary interrupter 8, a hook stick is inserted into opening 26 and a downward pull exerted thereon. This operation separates upper contact 23 of the fuse holder from its associated contact 21 as explained. Subsequently auxiliary contact 17 engaged behind shoulder 67 of conducting contact latch 16 secured to the ward movement of the lower cap 56 and of the outer housing element 51 since these parts are securely affixed to the lower end of the stabber by any suitable means such as by pins 68. Since the contact fingers 61 at their ports 64 securely grip the recessed portion 63 f the stabber 62, the finger contacts 61, the ferrule 60 and the inner tubular housing element 50 are drawn downwardly until such time as the outwardly projecting flange 53 engages the inwardly projecting shoulder 69 formed in the outer housing element 52. When this occurs, continued force applied to the stabber 62 of the order of magnitude of thirty pounds or. so causes separation of the shoulder portion 63 of stabber 62 from the gripping portion 64 of the finger contacts 61. Immediately following separation ofthese parts, the opening spring 65 immediately urges the inner tubular housing element 50, the ferrule 60 and contact fingers 61 upwardly and quickly draws an arc between the finger contacts 61 and the stabber 62 which arc is extinguished by are extinguishing structure generally designated by the numeral 73 and which is of conventional construction. The gases and other products ofinterruption may be vented to atmosphere through ports 74 formed in cap 56.  
  After interruption, the auxiliary contact 17 releases the surface 67 of the conducting latch 16 at some point during its clockwise rotation about the trunions 30. When such separation occurs, the parts which they may occupy a position such as that indicated in FIG. 9 are restored to the condition depicted in FIG. 7 by means of the closing spring 66 which as will be obvious is charged during the contact separating movement of the contacts imparted by the opening spring 65. Thus the closing spring 66 is never biased until an opening operation begins and then the major portion of its energy is imparted thereto during the later stages of a contact separating operation. Of course opening spring 65 is a relatively strong spring compared to closing spring 66 which sometimes is referred to as a reclosing spring.  
  From the above description and from the drawings, it is apparent that atno time is the opening spring 65 or the closing spring 66 exposed to the flow of current or even to the are which is drawn by the arcing contacts since these springs are always interposed between the inner housing element 50 and the outer housing elements 51 or 52. Furthermore none of the conducting parts is exposed in such manner as to constitute a hazard to an operator since the live parts are always completely enclosedwithin the insulating inner and outer tubular housing elements. Furthermore since the reclosing spring need only be a weak spring, and since according to the invention this spring is energized during the later stages of an opening operation by the relatively strong opening spring, the force required to withdraw the stabber 62 from its closed circuit condition to its open circuit condition as represented in FIG. 9 is less than might otherwise be required as for example in those structures where both an opening and a closing spring are charged manually by an operator during a circuit opening operation.  
  From FIGS. 4 and it is apparent that the mounting bracket 10 is relatively rigid in a ,vertical direction due to the fact that the material from which it is formed is substantially larger in its vertical dimension as shown in FIG. 5 than in its horizontal dimension as shown for ex ample in FIG. 4. Thus the mounting bracket constitutes a y ieldable mounting which accommodates limited &#39;sidevvise&#39; movement of the interrupter but which virtually precludes substantial vertical movement of the interrupter. Thus when thelcircuit is being opened manually as by means ofa hook stick, inherent flexibility prevents or reduces substantially any tendency of the relatively movable parts to bind should the operator exert an opening force at an angle to the normal plane of swinging movement of the fuse holder. I  
  The embodiments of the invention in which an exclusive property or privilege is claimed as defined as follows:  
  1. An electric circuit interrupter comprising housing structure, a pair of relatively movable contacts disposed within said housing structure and normally latched closed, opening biasing means for separating said contacts upon release of said contacts from their latched closed condition, and closing biasing means energized by said opening biasing means for imparting relative closing movement to said contacts, the opening force imparted to said contacts by said opening biasing means substantially exceeding the closing force imparted to said contacts by said closing biasing means.  
  2. An electric circuit interrupter comprising an inner tubular housing element ofinsulating material, a pair of outer tubular housing elements formed of insulating material and telescopically mounted respectively about opposite ends of said inner tubular housing element, said outer housing elements being movable relative to each other and to said inner housing element, a pair of relatively movable contacts one of which is mounted in fixed relation to said inner housing element and the other of which is mounted in fixed relation to only one of asid outer housing elements, and a pair of operating springs interposed respectively between said inner tubular housing element and said pair of outer tubular housing elements, said springs being isolated from said contacts and from atmosphere by said housing elements.  
  3. An electric circuit interrupter according to claim 2 wherein one of said springs is interposed between said inner housing element and said one outer housing element and is effective to bias said contacts toward closed positions.  
  4. An electric circuit interrupter according to claim 2 wherein one of said springs is interposed between said inner housing element and the other of said outer housing elements and is effective to bias said contacts toward open circuit condition.  
  5. An electric circuit interrupter according to claim 2 wherein an end portion of one of said outer housing elements is disposed within the adjacent end portion of the other of said outer housing elements and wherein said other outer housing element is disposed at a level above said one outer housing element when said contacts are closed so as to shield the interior of the housing from atmosphere precipitation.  
  6. An electric circuit interrupter according to claim 2 wherein said inner housing element is provided with outwardly projecting flanges at its ends and wherein each of said outer housing elements is provided with an inwardly projecting flange at its inner end.  
  7. An electric circuit interrupter according to claim 5 wherein a closing spring is interposed between the flange on said one of said outer housing elements and the adjacent flange on said inner housing element.  
  8. An electric circuit interrupter according to claim 7 wherein an opening spring is interposed between the other flange on said inner housing element and the flange on the other of said outer housing elements.  
  9. An electric circuit interrupter according to claim 7 wherein said closing spring is energized by said opening spring during a circuit interrupting operation.  
  10. An electric circuit interrupter according to claim 2 wherein the other of said outer housing elements is mounted on and supported by a fixedly mounted mounting bracket which is somewhat yieldable in a direction transverse to the axis of the interrupter.  
  11. An electric circuit interrupter comprising housing structure, a pair of relatively movable contacts dis- .posed within said housing structure and normally latched closed, opening biasing means for separating said contacts upon release of said contacts from their latched closed condition, and closing biasing means energized by said opening biasing means for imparting relative closing movement to said contacts.  
  12. An interrupter according to claim 11 wherein said closing biasing means is energized by said opening biasing means during the final stages of a contact opening operation.  
  13. An interrupter according to claim 11 wherein said housing structure is arranged to isolate said opening and said closing biasing means from said contacts.  
  14. An interrupter according to claim 11 wherein said housing structure is arranged to isolate said opening and said closing biasing means from atmosphere