US2314661A - Circuit interrupter - Google Patents

Description

March 23, 1943. H, L, RAWLINS 2,314,561

CIRCUIT INTERRUPTER Fild Dec. 21, 1939 3 Sheets-Sheet 1 N l u INVENTOR Herbe/ L. Pazo/i725.

BY q A ORN Q M Sw ww WITNESSES:

f ///////////J// n March 23, 1943. H. L. RAwLlNs CIRCUIT INTERRUPTER Filed Dec 21 M59 5 Sheets-Sheet 2 YSMWN March 23, 1943g H. L. RAwLlNs CIRCUIT INTERRUPTER Filed Dec. 21, 1939 3 Sheets-Sheet 3 .QN @WN q B 7'2/ ATTORN Patented Mar. 23, 1943 Westinghouse Electric & Manufacturing Company, East Pittsburgh,

1,ennsylvania Pa., a corporation of Application December 21, 1939, Serial No. 310,403

16 Claims. (Cl. 2ML-,114)

My invention relates in general to circuit interrupting devices, and more particularly to interrupters which are adapted to drop out of the circuit or in some manner give a readily visible signal or indication, following an interrupting operation.

My invention will be disclosed particularly in y connection with that type of interrupter utilizinga fuse which is adapted to be enclosed in an insulating box when in the closed circuit position.

, One object of my invention is to provide an enclosed fuse cutout construction embodying novel means for aiIording a visual indication or signal of an interrupting operation of the device.

Another object of my invention is to provide a novel arrangement of supporting means for a fuse or other interrupting device constructed so as to permit the device to drop out, that is, to move to an open-circuit position in response to a l circuit interrupting operation of the device.

Another object of my invention is to provide an enclosed fuse cutout with novel means for separating the fused portions of the fuse links when the fuse blows.

Another object of my invention is to provide an enclosed drop-out fuse of novel construction to insure ,the drop-out action of the fuse only an appreciable time after the fuse has blown, to prevent arcing at the fuse terminals.

A still further object of my invention is to provide a novel arrangement of a fuse and door of a fuse enclosure.

These and other objects of my invention will become more apparent uponconsideration of the following detailed description of preferred embodiments thereof, taken in connection with the attached drawings, in which:

Figure 1 is a vertical cross section view of one form of enclosed circuit interrupting device embodying my invention with the housing door and all parts within the enclosure being shown in elevation;

Fig. 2 is a cross sectional view of the lower portion of the housing similar to the view shown in Fig. l, but showing the fuse and door in a dropout or indicating position, this being the position these parts assume following the blowing of the fuse;

Fig. 3 is a view of the lower end of the enclosed cutout construction shown in Fig, 1;

Fig. 4 is a perspective view of the door supporting link used in the construction shown in Fig. l;

Fig. 5 is a transverse cross sectional view'taken substantially on the line V--V-of Fig. 1;

Fig. 6 is a partial vertical cross sectional view of a device similar to that of Fig. 1, but showing a slightly modified form of supporting means for the housing door;

Fig. 7 is a partial vertical cross sectional View `of the upper end oi a fuse housing similar to that of Fig. 1, but showing an upper contact construction adapted to render the cutout indicating but non-drop-out;

Fig. 8 is a cross sectional view of an interrupting device similar to Fig. 1, but. showing a modied lower contact and fuse terminal construction to provide a double air gap in the circuit when the fuse blows and drops out Fig. 9 is a vertical cross sectional View of the lower part of the housing, shown in Fig. 8, with the vfuse and door shown in the drop-out or indicating position, this being the position the parts y assume after the fuse blows in this form of my invention; and

Fig. 10 is a vertical cross sectional view of the lower portion of a slightly modified form of enclosed cutout.

In general, the cutout in which I have embodied my invention comprises an insulating housing having open front and bottom sides, with a fuse pivotally mounted at its lower end for movement into and out of engagement with at least one contact secured in the housing. A door for the front opening of the housing is longitudinally slidably mounted on the fuse tube and is maintained in an upper position by the fuse link. In one form of my invention, the door cooperates with a latch to maintain the fuse and door in a closed position with respect to the housing contacts and the housing, respectively.

Obviously, in this form of my invention when theV fuse blows, the door can slide downwardly away from the latch and inasmuch as the door is positioned in an offset relation relative to the fuse pivot axis, it will deliver an impact to the fuse when its sliding motion is stopped to rotate the fuse and door outwardly relative to the cutout housing.

door in its sliding movement along the tube and I will hereinafterspecically describe two of the preferred methods of supporting and guiding the door from the tube. Likewise, my invention is equally adapted for a cutout of a type where' either a single or double air gap is introduced in the circuit when the fuse moves to a drop-out position with respect to the housing. I have accordingly illustrated my invention as applied to both a single and double air gap construction.

AReferring to Figs. 1 to 5 of the drawings, in the embodiment illustrated here, I have shown an insulating housing 2 which may be made of any desired insulating material, preferably porcelain or glass, which housing embodies open, front and bottom sides. The housing itself includes a rear wall 4, a top wall 6 and side walls 8. The front edges of the side and top walls are recessed to provide a door seat I8 extending about the top and sides of the front opening. 'I'he rear wall of the insulating housing 2 is provided with an opening I4 in which is secured a housing supporting strap I 8 in any desired manner, such, for example, as by cement I8 which may be poured into the opening around the end of the strap I6, or the material I8 may comprise a suitable cast metal. Adjacent the top and bottom of the rear housing wall 4 are provided inwardly opening depressions 20 in which are secured nuts 24 by the bonding material 22 which may be of the same compositionl as the bonding material I8. Intermediate of the height of the rear housing wall 4 there is provided an inwardly projecting barrier 26 integral with the housing wall. An upper contact block 28 of conducting material such as copper or the like, is suitably apertured for the reception of a bolt 38 which extends therethrough to secure the same to the housing wall by means of the upper nut 24. An upper resilient contact and latch member 32 of any desired resilient conducting material such as a copper alloy, is of substantial U-shape with its base portion 34 positioned between the rear wall 4 of the housing and the contact block 28 and suitably apertured for the passage therethrough of the bolt which also acts to secure the contact and latch member 32 in fixed relation to the insulating housing 2.

The member 32 includes an upper resilient contact leg 36 for engagement with the upper terminal of a fuse, and a resilient lower or latching leg having a depressed portion 38 for receiving a cooperating part on the housing door for latching the same in its closed position. The contact block 28 is further provided with a transverse aperture 40 for receiving an electrical lead wire for connecting the contact to an electric circuit, and which wire may be secured in the aperture 40 as, for example, by the set screw 42. The lower contact 44 of conducting material like the block 28, is substantially U-shaped in form, as better shown in Fig. 3. The base 48 of the lower contact 44 is apertured for the passage therethrough of a. bolt 46 which threadedly engages with the nut 24 secured in the rear housing wall 4, to secure the lower contact 44 in position in the housing. The lower contact 44 has an integral upstanding portion 50 which is apertured to receive another circuit conductor which may be secured in place by a set screw 52. The lower contact 44 is provided with spaced forwardly extending arms 54, terminating in hooked portions 56 for pivotally receiving pintle portions 16 provided on the lower fuse terminal.

The fuse proper, includes an insulating tube 58 which may be of any desired insulating material such, for example, as fiber or a synthetic resin which is capable of evolving an arc extinguishing gas when in proximity to an electric arc. 'I'he fuse tube is provided with an upper conducting terminal sleeve 88, the upper end of which is covered by an upper conducting knuried terminal cap 82 threadedly engaged in the terminal sleeve 88. The terminal cap i2 is utilized to clamp the upper end of the fuse link to the fuse terminal sleeve 88 with the fuse link extending downwardly thereirom through the fuse tube 58 and out the lower end thereof as at 84, to be secured to the lower'fuse terminal as by a knurled nut 8G. The lower fuse terminal includes a conducting sleeve portion i8 slipped over the lower end of the tube and secured adjacent the lower end thereof as by the indented portion 18. Extending rearwardly from the lower terminal sleeve 88 are integral spaced arms 12 having a connecting bridge 'I4 spanning the upper sides thereof adjacent their ends for supporting the screw for the knurled nut 8i. At the rear ends of the arms 12, there are provided integral oppositely extending pintle portions 18 adapted to be received in the hooked portions I8 of the lower contact 44 for pivotally supporting the fuse tube on the lower contact. The lower terminal arms 'I2 extend downwardly from the pintles 16 and terminate in hooked portions 'I8 for pivotally receiving the door supporting link to be hereinafter described in detail. The housing door 88 is provided with integral rearwardly extending spaced channel forming ilanges 82 for receiving the fuse tube 58 therebetween. Transverse integral supports 84 are provided between the flanges 82 adjacent the top and bottom of the door for supporting one side of the fuse tube, and these transverse supports 84 include concave central portions 85 for receiving and centering the fuse tube. Retaining pins 88 and 88 are passed through apertures in the door flanges 82 and span the flanges to prevent movement oi the fuse tube out from between the iianges. The pins 88 and 88 may be secured in the position shown in Fig. 1 by any desired means, such, for example, as by the cotter pins 88.

It is believed obvious that by virtue of this construction, the door is relatively loosely, slidably mounted on the fuse tube for movement generally longitudinally of the tube. The door, however, normally is maintained in an upper position in relation to the fuse tube by the fuse link in a manner now to be described.

A connecting, or door supporting and guiding v link 92 is provided between the lower fuse terminal and the housing door and is more particularly shown in Fig. 4. As shown, the connecting link 92 is formed from the single piece of stiff wire or rod which may be of relatively stii steel or the like, and includes ODDOSitely extending intermediate spaced pivot portions 84 which are received in the hooked ends 18 of the lower fuse terminal arms 12. The supporting link 92 also includes outer outwardly extending spaced pivot portions 86 adapted to be received in apertures provided in the door flanges 82, respectively, for pivotally linking the lower end of the door to the lower fuse terminal. As seen in Fig. 4, the connecting link 82 is substantially in the form of a bell crank and includes an angularly extending U-shaped, or bight portion 88, forming th'; other arm of the bell crank and through which the end 84 of the fuse link is passed.

It is believed obvious from the structure thus far described that in the position shown .in

tion relative to the fuse tube 53 by engagement of the fuse link 6l with the bight portion 3l of the door supporting link 62. The door is provided with av front handle portion |66 which may be manually grasped, or engaged by a hook stick or other operating member to open the door and move the fuse and door about the fuse pivot 16 to an open position. In closing the door, it is obvious that the resilient. contact leg 3B of the contact and latch member 32 will engage the terminal cap 62 on the upper end of the fuse, and due to the fact that the outer end of the contact arm 36 is inclined upwardly, it will ride along the top of the cap and be cammed thereby to a stressed condition in the position shown in Fig. l. connects the door tlanges! will engage the upwardly inclined edge |02 of the resilient latch arm of the member 32 to cam this arm upwardly so that the pin may ride into the concave portion 36 of the latch arm, thus latching the door in a closed position with respect to the housing and connecting the upper terminal of the fuse to the upper contact block 28 through the contact arm 36. The lower terminal of the fuse is, of course, electrically connected to the lower contact M through the pivot 16.

Upon the occurrence of currents, in the circuit in which the cutout is connected, greater than a magnitude predetermined by the size or rating of the fuse link employed, the fuse link will the influence cf gravity with a sliding movement along the fuse tube until the pin 8E is removed to a point spaced below the latch arm, and thepin 88 engages the upper edges of the lower terminal arms 12. This engagement will be in the nature of an impact delivered at a point spaced from the fuse pivot 1S, thereby producing a couple tending to rotate the iuse about its pivot- 16 out of the casing and hence out of engagement with the upper contact arm 35. The downward movement of the door 80 is given an initial impetus by the latch arm which is stressed upwardly and hence will exert a downward force on the door. The latch arm exerts a force Similarly, the pin 66 which directly downwardly on the door tending to ini- .into play to aid in moving the tube outwardly This will obviously result, i since the point at which the contact arm 35 about its pivot 16.

engages the fuse terminal cap 62 is also odset from the fuse pivot 16, in providing a couple tending to rotate the fuse about its pivoty 16. The outward pivotal movement of the fuse tube carrying the door 80 with it, may continue until the door and fuse assume a depending vertical position However, it is preferred to stop this movement at approximately a a position, as shown in Fig. 2. The stopping is accomplished by engagement of the rear edge of the hooked portion 18 on the fuse terminal arms 12 with the web 48 of the lowercontact 44.

It is to be especially noted that when the door first slides downwardly along the fuse tube 58. the door supporting link 92 is rotated in a clockwise direction about its intermediate pivot portions 94 while the fuse tube remains stationary, thus causing the lower unburned end 64 of the fuse link to be withdrawn from the fuse tube vdisengage the resilient contact arm 36.

with a relatively rapid motion to quickly separate the unburned ends of the fuse link, and draw out the resulting arc into contact with a relativelylarge portion of the inner area of the fuse tube which will thereby evolve greater quantities of arc extinguishing gas to aid in-extin guishing the arc before the fuse tube moves to This insures that there will be no arcing between the contact arm 36 and the upper fuse terminal cap 62.

When the fuse has attained the position shown in Fig. 2, it' may be easily re-fused by lifting the door upwardly so that the lower fuse terminal pivot 16 is removed from the lower contact hooks 56, whereupon the door and fuse may be removed to a convenient location for renewing the fuse i link. The unburned portions of the old fuse link may then be removed by unscrewing the lower knurled nut 66 on the lower fuse terminal and the upper fuse terminal cap 62. A'new link may be then drawn through the fuse tube and secured by tightening the knurled nuts 62 and 66 down upon the ends thereof, with the length of the fuse link adiusted to bring the door supporting link 92 to the position shown in Fig. l, to

move the door to its upper position shown in this figure, whereupon the fuse pivots 16 may be renserted in the hooked portions 56 ofthe lower housing contact and the door and fuse pivotally moved to a closed position with respect to the housing and the upper Contact arm 36.

In Fig. 6 of the drawings, I have shown a slightly modified form of engagement between the cutout door and the door supporting link 92. Otherwise, this construction is much the same as the construction just described in connection with Figs. 1 to 5 of the drawings and, therefore, like reference numerals will be employed to designate like parts. In the embodiment described in connection with Figs. 1 to 5 of the drawings, it will be noted that when the fuse blows and the door moves downwardly, the lower end of the door. due to the pivot liik connection 92 between the door and the lower fuse terminal, will move slightly outwardly with the pivot portions 9G of the fuse supporting link describing an arc about the pivot portions 94 as a center. Hence some work will be done in moving the lower end of the door laterally which might be applied to more advantage in moving the door with a substantially purely rectilinear downward motion of the fuse tube. Such a motion can be accomplished with the structure shown in Fig. 6. wherein the pivot portions 96 of the door supporting link are shown as being received in horizontal slots |04 provided in the door flanges 82. It will be obvious with this vconstruction that the lower end of the door will not be moved outwardly when the door initially slides down on the fuse tube, but that this movement will be substantially a rectilinear movement and thus the total force due to the action of gravity on the door tending to move itv downwardly, and the action of -the latch arm on pin 86 will be utilized in delivering an impact to the lowei' fuse terminal arms 12 to cause rotation of the fuse and with it the door about the fuse pivot 16 to a drop-outposition similar to that shown in Fig. 2.

The rest of the structure shown in this embodiment of my invention is identical with that shown and described in connection with the embodiment of my invention shown in Figs. l to 5 and hence the description of these parts and the complete operation of this construction will not be repeated.

In Fig. 7 of the drawings, I have shown a structure where the door of the fuse casing slides down to indicate blowing of the fuse, but is prevented from dropping out. Only the upper portion of the fuse housing and door are shown inasmuch as the remaining structure is identical with that heretofore described in connection with Figs. 1 t0 5. As shown in Fig. '1. the upper contact leg 3i has an outer curved portion |06 for releasable latching engagement with a concave seat lll provided on the upper fuse terminal cap Ill.. The resilient contact 36 in this embodiment of my invention performs two functions, that is, it acts to electrically connect the contact block 2l with the upper fuse terminal sleeve 60, and also acts as a latching means directly engaging the fuse itself.

It should be apparent that when the fuse blows the door 80 will slide down as before and withdraw the lower unburned end of the fuse link from the fuse tube 5B, but this movement of the door downwardly does not act to release the latch maintaining the fuse in its closed circuit position, and hence the fuse will remain in position and the door will remain in a position corresponding to the dotted line position shown in Fig. 7 to give a readily visible indication that the fuse has blown.

In Figs. 8 and 9 of the drawings, I have shown an enclosed cutout construction which generally is much the same as that shown in Figs. 1 to 5 of the drawings, but differs therefrom in a modied lower support and contact construction.

Referring particularly to Fig. 8, the lower fuse terminal arms l2 are provided with a terminal bar ||ll pivotally mounted between them on the pivot pin |I2. A spring ||4 has its mid-portion coiled about the pivot pin ||2 and engages at its free ends with the terminal bar HU and the terminal sleeve 68, respectively. The spring ||4 acts to continuously urge the terminal bar H0 in a counterclockwise direction, as viewed in Fig, 8, about its pivot` I|2. When the fuse is open or when it has dropped out, a's shown in Fig. 9, this clockwise movement of the terminal bar is limited by an integral extension lli on the bar ||0 which engages with the lower fuse terminal sleeve 68. as seen in Fig. 8, is removed from the pivot support for the fuse and is secured in an aperture |20 in the rear housing wall spaced above the pivotal support |34 for the fuse. A nut |24 is secured in the rear housing Wall aperture |20 by suitable material |22 which may be the same as material I8 previously described, and the contact block |I8 is secured to the rear housing wall by the bolt |26 passing through a suitable aperture in the contact block for threaded engagement with the nut |24. The contact block Ill is provided with a transverse aperture |28 for receiving an electrical conductor which may be secured in place by the set screw |30. The contact block H8 further includes a forwardly projecting contact portion |3I adapted to be engaged by the terminal bar i0. 'Ihe pivot support for the fuse pivot 16 includes spaced hooked leg portions |32 and a connecting apertured base portion, through the aperture of which is passed a bolt |36 to threadedly engage with the nut |24 to secure the pivot support |34 to the rear housing wall, in the same manner the combined pivot support and contact 44 is secured to the rear housing wall in the embodiment shown in Figs. 1 to 5.

The lower housing contact,

Intheoperationofthistofmyinventiomthesupportofthe dooronthefuseand themannerinwhichthedoorslidesdownto withdrawtheimburncdportionofthe fuselink andtocauserotatimofthe fuse anddoor about thefusepivot litoadrop-outpodtiomisthe same as that previously described in connection withtheembodimentshowninligslto. However, it should be noted in this embodiment of my invention that when the fuse and door movetoadrop-outposition,boththeupperand lower fuse terminals are disconnected from the upper and lower housing contacts to thus insert two air gaps in the circuit. The circuit through the fuse in this form of my invention is from the upper contact block 2l through the contact arm 34 to the upper fuse terminal cap l2, throughthe fuselinktothefuseterminalbar ill, and the lower housing contact block III. 'I'he advantage of this construction resides in the fact that when the fuse has blown and has dropped out to an open position, or when the fuse is manually moved to an open position, the fuse and all parts movable therewith are electrically deadsssoonasexposedandhmcemaybe handled in safety. The lower terminal bar III of the fuse provides a resilient terminal connection with the lower contact portion |3| in the fuse housing, by virtue of the bias exerted by the spring ||4. After this fuse has blown,.it may be re-fused in the same manner described in connection with the embodiment shown in Figs. 1 to 5, and hence to avoid repetition this procedure will not be repeated here. n

InFig. 10,Ihaveshownapartialviewofan enclosed cutout construction similar to that shown in Figs. 8 and 9, but showing a slightb modified form of resilient connection between the lower fuse terminal and the lower housing contact. Here, instead of providing the lower fuse terminal with a resiliently biased pivoted terminal portion as in Pigs. 8 and 9, the terminal arms 12 areprovided with an integralrigid opstanding terminal portion |42 which 1s engageable with a resilient housing contact construction. The contact block l Il is secured to therearhousingwallinthesamemannerasin Figsand9andsecuredtoaninclinedupper edge thereof are a plurality of resilient conducting leaf members |44, which may be of any desired conducting material which is resilient, such for example, as a copper alloy such as bronze or phosphor bronze. These conducting leaf members |44 are secured to the contact block III as by the machine screw |38, and the leaves, as shown in Fig. 10, are progresively longer in length, or project slightly further away from the contact block III in a direction toward the block, thus providing a resilient conducting leaf structure which is adapted to be engaged by the rigid terminal portion |42 on the lower fuse terminal when the fuse is in the closed position. Otherwise, the remaining parts of the construction shown in Hg. 10 are identical with that shown in Figs. 8 and 9 and hence these parts will not be again described nor will the operation be repeated, since it is believed to be obvious from the foregoing.

It should be apparent from the foregoing that I have provided a novel type of enclosed drop-out fuse construction wherein, when the yfuse blows, it remains stationary for a predetermined length of time while the door for the enclosure slides along the fuse tube to withdraw one unburned end portion of the fuse link, and ilnally to deindicating position.

liver an impactlto the fuse tube to initiate its movement out of the enclosure to a drop-out or It should also be obvious that by providing a latch for the fuse tube instead of for the door, the fuse may be retained in its closed position when the fuse link blows, merely allowing the door to slide downwardly and pull out the fuse link to thereby give an indication of the condition of the fuse. Also, I have shown my invention as embodied in two diierent contact constructions one wherein the pivotal support for the fuse is combined with one line contact and the other where both line contacts are separated from the pivotal support for the fuse so that when the fuse is moved to an open position, two air gaps will be inserted in the circuit and the fuse will be electrically dead.

Having described preferred embodiments of my invention in accordance with the patent statutes, I desire that my invention be not limited to the particular embodiments described herein inasmuch as it will be' obvious, particularly to persons skilled in the art, that many changes and modifications may be made in the particular structures shown without departing from the broad spirit and scope of my invention. Therefore, I desire that my invention be limited only by what Iis expressly included in the following claims.

I claim as my invention:

l. In a circuit interrupting device, means for automatically interrupting a circuit in response to the passage therethrough of currents above a predetermined value, said means being movably mountedso that a terminal portion thereof may move into or out of engagement with a cooperating contact, an open-sided housing for said means in which said contact is supported, a closure for said open side of the housing slidably mounted on said interrupting means, said interrupting means being adapted to be releasably secured in said housing with said terminal portion in engagement with said contact, said interrupting means normally maintaining' said closure in closed position relative to said housing but releasing the same upon an interrupting operation thereof to permit sliding movement of said closure thereon to provide a visual indication. of the condition of said interrupting means.

2. In a circuit interrupting device, means for automatically interrupting a circuit in response to the passage therethrough of currents above a predetermined value, said means having a laterally extending pivot arm to pivotally mount said interrupting means so that a terminal portion thereof may move into or out of engagement with a cooperating contact, an open-sided housing for said means in which said contactv and a pivot support for said arm are supported, a closure for said open side of the housing slidably mounted on said interrupting means and adapted to be releasably secured in closed relation with respect to said housing with said terminal portion in engagement with said contact, said interrupting means normally maintaining said closure insaid position but releasing the same upon an interrupting operation thereof to permit sliding movement of said closure thereon to release the same and permit movement of the interrupting means and closure away from the housing, a part on said closure adapted to engage said pivot arm to limit said sliding movement and deliver an impact to said pivot arm at a point spaced from the pivot thereof and in a direction to cause movement of said interrupting means and closure away from said housing.

3. In a. circuit interrupting device, means for automaticallyinterrup'ting a circuit in response to the passage therethrough of currents above a predeterminedl value, said means having a laterally extending pivot arm adapted to be pivotally mounted so that at least one terminal of said means may move into and out of engagement with a. cooperating contact, means slidably mounted on said interrupting means and Aadapted to be releasably securedin a position wherein said terminal portion is in engagement with said contact, said interrupting means normally preventing sliding movement of said second mentioned means thereon, but permitting such movement following an interrupting operation thereof to release said two means, and a part on said slidable means adapted to engage said pivot arm to limit said sliding movement and deliver an impact to said pivot arm at a point spaced from the pivot thereof and in a direction to cause movement of said two means away from said contact.

4. In a circuit interrupting device, a fuse supporting member, a housing closure member slid- 'ably mounted on said supporting member, laterally extending supporting means on said fuse supporting member for supporting both of said members on a. housing, and a part on said closure member positioned to engage said supporting means for limiting said sliding movement in one direction.

5. In a circuit interrupting device, a movably mounted fuse tube having a pairoi terminal pormeans connected between said siidabie means and tube for limiting sliding movement, said fuse link normaliy maintaining said slidable means in one position, and releasable iatching means for maintaining said one fuse terminal in engagement with said contact, whereby upon blowing of the fuse link said slidable means is free to slide along said fuse tube to give a visual indication of the operation.

6. In a circuit interrupting device, a movably mounted fuse tube having a pair of terminal portions at least one of which is .movable with the tube into and out of engagement with a cooperating contact, a fuse'link in said tube and normally connecting said terminal portions, means slidably mounted on said tube, bell crank means having one arm pivotally connecting said slidable means and tube for limiting sliding movement, said fuse link normally engaging the other arm of said bell crank means for maintaining said slidable means in one position, and releasable latching means engaging said slidable means in the normal position thereof, whereby upon blowing of said fuse link said slidable means is movable along said tube to release said latching means to permit disengagement of said one terminal and contact.

7. In a circuit interruptingdevice, a movably mounted fuse tube having a pair of terminal portions at least one of which is movable with the tube lnto and out of engagementwith a cooperating contact, a fuse link in said tube and normallyA sliding movement, said limiting means including a part engageable with said fuse link for normally maintaining said slidable means in one position relative to said fuse tube, and releasable latching means engaging said slidable means in the normal position thereof, whereby upon blowing of said fuse link, said slidable means is movable along said tube to release said latching means to permit disengagement of said one terminal and contact, and to separate the uniused portions of said :fuse link.

8. In a fuse cutoutconstruction, a housing, a contact in the housing, a fuse tube movably mounted n said housing to move a terminal portion thereof into and out of engagement with said contact, a door for said housing slidably mounted on said fuse tube, a fuse link insaid tube normally maintaining said door in one position with respect to said housing, and means for releasably latching said tube in said housingwith said terminal portion in engagement with said contact, said parts being arranged so that when said fuse link blows, said door is thereby released and slides t an indicating position.

9. In a circuit interrupting device, a fuse supporting member, a housing closure member loosely slidably mounted on said supporting member, pivoted link means connecting said members for limiting said slidable movement, and supporting means on said fuse supporting member for supporting both of said members on a housing- 10. In a fuse cutout, a door for a cutout housing having spaced, substantially parallel anges extending substantially laterally from the inner side thereof for supporting a fuse holder therebetween, and detachable means connecting p0rtions of said flanges spaced from said door for preventing movement of said fuse holder from the space between said iianges.

11. In a fuse cutout, a door for a cutout housing having spaced, substantially parallel flanges extending substantially laterally from the inner side thereof for supporting a fuse holder therebetween, means including a latch pin connecting portions of said fiang spaced from said door for preventing movement of said fuse holder from the space between said flanges, said pin having at least one portion thereof adjacent one of said anges for engagement by a latch.

12. In a fuse cutout, a door for a cutout housing having spaced, substantially parallel ilanges extending substantially laterally from the inn'er side thereof for supporting a fuse holder therebetween, means including spaced pins, connecting portions of said flanges spaced from said door for preventing movement of said fuse holder from the space between said anges, one of said pins having at least one portion thereof adjacentA one of said flanges for engagement by a latch, and the other of said pins engageable with a lateral projection on said holder for limiting relative longitudinal movement of said door and holder in one direction.

13. In a fuse cutout, a housing of insulating material, a contact mounted in the upper portion of said housing, a fuse tube plvotally mounted adjacent its lower end in said housing to move a terminal adjacent the upper end of said tube into and out of engagement with said contact, a door for said open side of the housing slidably mounted on said fuse tube, fusible means in said tube normally maintaining said door in an upper position with respect to said tube wherein said door closes said open side of the housing, releasable latch means engageable with said tube adjacent the upper end thereof for normally holding said tube in said housing with said terminal in engagement with said contact, whereby when said fusible means melts said door is released to slide downwardly on said tube to an indicating position.

14. In a fuse cutout construction, a housing, a contact in the housing, a fuse tube movably mounted in said housing to move a terminal portion thereof into and out of engagement with said contact, a door for said housing slidably mounted on said fuse tube, pivoted link means connected between said door and tube for limiting sliding movement of said door on the tube, a fuse link in said tube normally maintaining said door in one position with respect to said housing, and releasable latching means for maintaining said fuse terminal portion in engagement with said contact, whereby upon blowing of the fuse link said door is free to slide along said fuse tube to give a visual indication of the operation.

l5. In a fuse cutout construction, a housing, a contact in the housing, a fuse tube movably mounted in said housing to move a terminal portion thereof into and out of engagement with said contact, a door for said housing slidably mounted on said fuse tube, a fuse link in said tube, bell crank means having one arm pivotally connecting said -tube and door for limiting sliding movement, said fuse link normally engaging the other arm of said bell crank means for malntaining said door in one position, and releasable latching means engaging said door in the normal position thereof, whereby upon blowing of said fuse link said door is movable along said tube to release said latching means to permit disengagement of said terminal and contact.

16. In a circuit interrupting device, a fuse tube of insulating material having spaced terminals thereon, conducting means in said tube connecting said terminals and including a fusible portion, a housing closure member loosely slidably mounted on said tube, pivoted link means connecting said tube and closure member for limiting said slidable movement, and said link means having a part engaged by said conducting means for normally maintaining said closure member at a predetermined position relative to said tube.

HERBERT L. RAWLINS.

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