US2359153A - Circuit interrupter - Google Patents

Description

Sept. 26, 1944. H.L. RAWLINS 2,359,153 CIRCUIT INTERRUPTER Filed May 3, 1941 3 Sheets-Sheet 2 WITNESSES:

INVENTOR gjbazmm Sept. 26, 1944. H. L. RAWLINS 2,359,153

CIRCUIT INTERRUPTER Filed May 3, 1941 3 Sheets-Sheet 3 WITNESSES: INVENTOR Patented Sept. 26,

2,359,153 7 cmcurr mrnnaurrsa Herbert L. Rawlins, Wllkinsburg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East- Pittsburgh, Pa.,

vania.

Pennsyl a corporation of Application May 3, 1941, Serial No. 391,644 33 Claims. (Cl. 200114) This invention relates, in general, to electric circuit interrupters, and more specifically, to drop-cut fuse cutouts.

One object of this invention is to provide a novel type of drop-out fuse which is of relatively simple construction and capable of ready and easy assembly and is eflicient in operation.

Another object of this invention is to provide a novel drop-out fuse construction especially adapted for use with an enclosed fuse structure.

Another object of this invention is to provide a fuse of the type described which is especially adapted for ready attachment or detachment with respect to supporting means and which may be attached or detached by means of a hook stick.

Another object is to provide a novel assembly of a fuse and housing door.

Another object of this invention is to provide novel means for securing a fuse link to a fuse terminal.

These and other objects of this invention will become more apparent upon consideration of the following detailed description of a preferred em bodiment thereof, taken in connection with the accompanying drawings, in which:

Figure l is a longitudinal sectional view through an enclosed fusecoutout embodying this invention, with the fuse shown in the closed circuit position;

Fig. 2 is a view like that of Fig. 1 but showing the fuse in an initial stage of its automatic dropout movement;

Fig. 3 is a partial sectional view of the lower end of a fuse like that shown in Figs. 1 and 2, and certain parts being broken away. to illustrate an attachment for preventing movement of the fuse when it blows;

Fig. 4 is a partial front view of the fuse shown in Figs. 1 and 2, with the fuse in an open dependingposition with respect to its housing;

, Fig. 5 is a bottom view of the fuse and door assembly shown in Figs. 1, 2 and 4;

Fi 6 is a transverse sectional view taken substantially on the line VI-VI of Fig. 1;

Fig.'-'l is an enlargedelevational view partially in section, of the fuse link securing means shown in Figs. 1 to 6; and

v Fig. 8 is a sectional view of the fuse securing means looking substantially in the direction of the arrows VIII-VIII of Fig. 7.

In the embodiment of the invention illustrated in the drawings, the fuse is preferably provided with an insulating housing, 2 which may be of any desired insulating material, preferably diepressed porcelain. The housing 2 comprises a rear wall 4, a top wall 6 and opposite side walls The rear wall 4 is provided with an .inwardly extending protuberance I 0 forming with the in tegral flange II a transverse bafiie intermediate the ends of insulating casing 2. The protuberance l0, as shown, is provided with a cavity opening to the outer side of wall 4 adapted to receive one end of a mounting supporting the casing, for example, from a crossarm hanger H adapted to be secured to the bracket 12 by bolt l6. Supporting bracket I 2 is preferably secured in the cavity of protuberance I0 by cementing material It which may be any well known type of cementingmaterial, or may be a metal cast in the cavity around bracket arm l2.

Within casing 2 there is provided upper and lower contact assemblies l8 and 20, respectively, secured in cavities in the inner surface of rear wall 4 of the casing. The upper contactassembly it includes a forwardly projecting contact strip 2| of any desired conducting material, such for example, as copper or the like, with a resilient backing strip 22 overlying conducting strip 2!. The outer end of conducting strip 2| is preferably bifurcated, and the outer end of resilient backing strip 22 is preferably formed with three spaced tine portions, the outer ones of which overlie the furcations of contact strip 2!, and

the middle one of which is formed with a downwardly projecting end portion 24 adapted to project downwardly between the furcations of contact strip 2|, to form a latch means for engagement with the upper end of a fuse, Similarly, the lower contact assembly 20 includes a contact strip 26 and resilient backing strip 28 overlying contact strip 26, and the outer ends of these strips are preferably provided with an arcuate cutout portion for receiving the fuse when in operative position within casing 2.

The contact and backing strips of both the contact assemblies I8 and 20 are mounted in positionin casing 2 by a substantially U-shaped clamp member 30 having an enlarged bight portiOn for the reception of a line conductor, with a screw 32 threaded through an aperture in one wall of the bight portion to clamp the conductor therein. The contact and backing strips are received between the outer ends of U-shaped clamp 30, as is one leg of an angled supporting bracket 34. Securing means, such for example, as screws 36, are adapted to extend through the legs of U-shaped clamp 30 and through apertures in the contact and backing strips, and each angled supporting bracket 34 is provided with bracket l2 for slots in the outer edge thereof for receiving intermediate portions of screws 38 so that the entire contact assemblies may be slipped on or off brackets 34 when screws 38 are loosened, and

may be secured to the brackets merely by tightening screws 35 when the assemblies are in position. The other legs of angled brackets 34 are secured in depressions formed in the inner surface of rear casing wall 4, preferably in the same manner that supporting bracket I2 is secured in the cavity of protuberance l8.

The above-described structure has not been described in great detail because this structure is more particularly disclosed and claimed in the copending application of H. L. Rawlins and E. H. Fischer, Serial No. 379,076, filed February 15, 1941, entitled Electrical apparatus, and assigned to the same assignee as this invention. Accord-- lingly, for a more complete description of the details of insulating casing 2 and contact assemblies,l8 and 2ll, and their association with casing 2, reference is hereby made to the aforesaid copending application.

-The open front of casing 2 is adapted to be closed by a door 38 of insulating material, such for example, as porcelain, a synthetic resin or the like. Door 38 comprises a door panel 48 having at the outer surface thereof an integral projection 42, extending outwardly and apertured as at 44, for the reception of a hook stick operating member, or the like, for manipulation of the door to open and closed positions with respect tq casing. 2. The inner surface of door panel 48 is provided intermediate the ends thereof with spaced, longitudinally extending integral flanges 45, adjacent the upper ends of which, as viewed in Figs.- 1 and 2, there is provided an integral projection 48 apertured-for the reception of a fuse 58.

The fuse 58 may be of a conventional form which "includes a fuse tube 52 of any desired insulating material, such as fiber or a synthetic resin. The upper end of the fuse tube has secured thereto in any desired manner, such for example, as by threaded engagement, an upper metal terminal ferrule 54 provided with a terminal cap 58 threadedly engaged with the outer end of the ferrule, for securing the head contact '53 of a fuse link in conductive relation with respect to ferrule 54 and cap 55. The lower end of fuse tube 52 is left open so that the tail 5| of the fuse linlq may extend out of the lower end of the fuse tube to be fastened to a lower terminal. The fuse link also may be of any conventional structure, and that illustrated includes a terminal head 53 and tail 5| connected by a fusible means contained'within an insulating tube 55 adjacent the upper end of fuse tube 52. This specific fuse link structure is more particularly disclosed and claimed in the copending application of James M. Wallace, Serial No. 294,- 073, filed September 9, 1939, on Circuit interrupters now Patent No. 2,343,723, issued March 7, 1944, and assigned to the same assignee as the 8 present application.

As shown in the drawings, fuse 50 is assembled with door 38 by threading fuse tube 52 downwardly through theaperture in projection 48, until terminal ferrule 54 is seated on the upper side of projection 48. flanges 51 are providedconnected with door panel 48- and'projection 48, and are joined by a curved wall portion to conform to the curvature 'of fuse terminal ferrule 54. Also, one of the flanges 51 is provided with a threaded apervture for receiving a set screw 58 to prevent removal of the fuse from projection 48, and set screw 48 is preferably adapted to be received in a side aperture in terminal ferrule 54.

Door panel 48 is also provided at the inner side thereof with a second integral projection 80 adjacent the lower end thereof, which is apertured for reception of the lower end of fuse tube V 52. That is, when fuse tube 52 is threaded through aperture in projection 48 until ferrule 54 engages the upper side of projection 48, the lower end of the fuse tube will then be received in the aperture provided in lower projection 58. Extending upwardly from lower projection 58 and integral therewith and with door panel 48, are spaced flanges 82 similar to upper flange 51,

and like these flanges, are joined by a curvedv connecting wall portion adapted to conform with the curvature of fuse tube 52. Flanges 82 are provided below flanges 46 and are spaced slightly inwardly of flanges 48, for a purpose which will hereinafter become apparent.

A supporting lower terminal assembly is adapted to be readily removably associated with the door and fuse assembly, and thisis accomplished by the provision of a transverse slot or groove 64 in the inner surface of door panel 48 intermediate lower flanges 82, for the reception of a curved rod-like member 58, having oppositely outwardly extending end portions 58 to form pintles adapted to extend outwardly through notches 18 formed in flanges 52. The rod-like member 86 is maintained in position in groove 54 by fuse tube 52, and may be readily assembled in position merely by withdrawing fuse tube 52 from the apertures in projections 48 and 88, placing the rod-like member 88 in groove 54 and then inserting the fuse tube in position, without the necessity of any other securing means or special tools; The pintle portions 58 on member 85 are adapted to pivotally support a supporting link 12 for the fuse and door assembly. As shown in the drawings, supporting link I2 comprises spaced side walls 14 apertured adjacent the upper ends thereof for the reception of pintle por- Integral upstanding tions 58, respectively, and an integral connecting wall 18 also located adjacent the upper ends of side walls 14 for rigidly connecting the sides of supporting link 12. Connecting wall I5 has the upper end thereof provided with an arcuate cutout portion to permit counter clockwise movement of the supporting link about pintles 58 by receiving fuse tube 52 during such movement.

The lower portion of supporting link 12 is provided with a slot 18 opening to one edge of the link and having a reentrant portion at the inner end thereof for receiving pivot pins 82 supported on side walls 8 of insulating casing '2. By the provision of such a slot in the supporting link, it will be apparent that the link may be readily attached and detached with reing pins 82 into slot 18. In the position of the 5 parts shown in Fig. 1 of the drawings, it will be noted that slot 18 in the supporting link lines up with notches 84 provided in opposite side edges of door panel 48 to perminthe link, when assembled with the fuse and door, to be engaged or disengaged with pivot pins 82. Notches 84 in door panel 48 preferably are flared outwardly to facilitate easy entrance of pivotpins 82 into the notches and slots 18 in the supporting link.

A contact lever 88 of any desired conducting material, such for example, as copper or the like.

is preferably formed with side plate portions 88 vconnected adjacent their upper ends, as viewed tion 90 is preferably extended beyond side plates 88 and bent substantially at right angles to 'form a contact terminal portion 92 for engagement with contact strip 28 of lower contact assemblyv 20, when the fuse is in operative position. Pref-.

erably, the contact terminal portion 92 also has a an arcuate cutout portion in the outer end thereof similar to thatin the outer ends of contact strip 28 and resilient backing strip 28, to receive fuse tube 52. The other end of connecting plate 90 of contact lever 88 is extended beyond the other ends of side plates 88 and bent angularly, for example, approximately at an angle of 45 to form a terminal portion 94 to which the fuse link tail may be secured. Contact lever 88, is pivotally associated with supporting lever I2, by pivot means 98 extending through corresponding sides of the supporting link and contact lever and may comprise rivets or the like. Preferably, the sides 88 of contact lever 88 are spaced apart a distance less than the sides I4 of supporting link 12, so that the sides 88 of the contact lever will fit between sides I4 of the supporting link.

Referring particularly to Figs. 7 and 8 of the drawings, it can be seen that the terminal portion 94 of contact lever 88 is apertured adjacent the outer end thereof for the reception of a headed stud 98 having an-inner portion I00 projecting through terminal portion 94 of the contact lever, with the inner portion I 00 beingnon-circular in form. The stud 98 also includes an outer threaded portion I02 for cooperation with a cupshaped nut I 04, the base portion I08 of which is provided with a threaded aperture for cooperation with the outer threaded portion I02 of the stud. Preferably stud 98 is made from square rod stock'which is turned to cut threads I02 .and to'cut off the corners of portion I00 in a single operation. A washer member I08 is interposed between terminal portion '94 of the contact lever and nut I04, and is preferably rotatably secured to nut I04 by integral tab portions IIO on the washer being bent over the open end of nut I04 and into peripheral groove 2 on the outer surface of the nut in a loose manner to prevent relative separating movement of the washer and nut while permitting relative rotative movement thereof. -Washer I08 is provided with an aperture also non-circular in form, similar to the form of inner portion I00 of stud 98,-so that upon rotation of nut I04, washer I08 is moved longitudinally of stud 98 but is maintained against rotation on the stud. I

to stress the fuse link in a manner to appreciably alter the rating thereof; Even where fuse links are provided with strain relief wires, as.

in the fuse link of the'aforementioned patent of James M. Wallace, these are necessarily limited in strength not only because of space limitations, but because it is essential that they be'fused instantly upon fusion of the fusible portion of the link and consequently cannot withstand much tension. Fuse links at present are designed to withstand a pull of about ten pounds, and this may readily be exceeded by the capstan'action and resulting relatively great mechanical ad- .vantage obtained, for example, by securing the tail of the fuse link with the aid of a pair of pliers beneath a rotatable clamping means, such as an ordinary bolt and nut. However, with the clamping means of this invention, it is obvious that washer I08 which directly engages the fuse link tail to clamp it to terminal portion 94 of contact lever 88, cannot rotate and, therefore,

, can assert no rotative effort on the portion of As stated before, the purpose of nut I04 is to secure tail 5I of the fuse link to contact lever 88, and the purpose of the specific structure of nut I04, stud 98 and washer I08, is toprevent capstan action on the fuse link tail upon tightening of nut I04. In other words, it has been the practice in the past to secure a fuse linktail to a lower fuse terminal by some sort of rotatable clamping means, so that when the fuse link tail is wrapped about the clamping means in the direction of rotation thereof to clamp the tail in position, tightening of the clamping means results in a certain amount of rotation of the fust link, tail with the clamping means and causes undue tension being placed upon the fusible portion of the fuse link, which even though it may not be sufllcient to break the relatively fragile fusible portion of the link, often is enough the fuse link tail in engagement therewith. This is an important feature because considerable difficulty has been experienced because of damage to fuse links caused by too much tension being exerted thereon.

With the tails SI of the fuse link secured to terminal portion 94 of contact lever 88, it is believed apparent that the contact lever will be prevented from rotating counter-clockwise about its pivot 96. The sides is of contact lever as are provided with integral forwardly extending locking projections II4 adapted to engage be- -neath integral stop lugs II8 provided on door panel 40 when the contact lever is maintained in the position shown in Fig. 1 of the drawings by fuse link tail 8|, so that supporting link I2 is positively locked by engagement of projection H4 and stop lug II8 against rotative movement in' a counter-clockwise direction about its pivot 88 on the door and fuse assembly or about pivot pin 82 on casing 2. Consequently, it can be seen that when a fuse link is inserted in fuse tube 82 and secured at one end by terminal cap 88 and at the other end to contact lever 88 by nut I04, the contact lever and supporting link strain on the fuse link, and when the door and fuse assembly are associated with the casing by slipping the notches in the lower end of the door over pivot pins 82, the door may then be rotated in a clockwise direction about pivot pins 82 to bring fuse terminal cap 58 into engagement with upper contact assembly I8, and contact portion 92 of contact lever 88 into engagement with lower contact assembly 20 with a. wiping action until latch portion 24 of a resilient backing strip 22 engages over the outer side of terminal cap 58 to maintain the door closed and the fuse in closed circuit position with respect to terminal assemblies I8 and 20. As the door and fuse are moved to the closed position shown in Fig. 1,v the fuse terminal cap 58 and terminal portion 92 of contact lever 88 eng ge the contact strips of the respective terminal assemblies which, as shown, have upwardly deflected outer ends so that the fuseterminals may be operative to inove the contact strips upwardly against-the"' bias exertfi" by backing strips 22 and 28, respectively, to thereby provide both a wiping engagement and final I contact of the contact strips and fuse terminals observed that both terminal assemblies I8 and 28, by virtue of the bias exerted'by their backing'strips 22 and 28, respectively, will exert a force substantially longitudinally of fuse tube projectionfli In the position of the parts shown in Fig. 2 of the drawings, it will be noted that substantially all of the door and fuse parts are positioned outwardly of a vertical plane extending through pivot pins 82 and that an integral stop projection II6 on each'side plate 88 of the 52, with the upper contact assembly exerting this force along the axis of fuse tube 52, which it will. be noted is displaced outwardly of pivot pins 82 so as to tend to cause movement of supporting link 12 in a counter-clockwise direction about pivot pins 82 and therefore tend to break the toggle comprising fuse tube 52 and supporting link I2 outwardly, and cause movement of the lower end of the fuse tube and door outwardly and downwardly to release the upper end of the fuse from latch 24. Similarly, lower contact assembly 28 exerts a force on supporting link 72 at its pivot 96 therewith, which is also offset outwardly relative to link pivot supporting pins 82 to also tend to cause movement of the supporting link in a counter-clockwise direction about pivot pins 82 and cause movement of the door and fuse outwardly of casing 2. Therefore, when the fuse link blows and fuse link tail 5] is no longer operative to mainto pivot with supporting link I2 in a counterclockwise direction out of casing 2 to depend therefrom in the manner shown in Fig. 4.

It should be-especially noted that initial movement of fuse58 when the fuse blows, is produced by pressure exerted by both backing strips 22 and 28 of" contact assemblies I8 and 28, respectively.

After fuse terminal cap 56 disengages upper contact assembly I8, pressure will continue to be exerted on. contact lever 86 by contact assembly 28 until the parts reach the position shown in Fig. 2, because the lever arm from pivot pins 82 to supporting lever pivot 68 being longer than the lever arm from pivot pins 82 to contact lever pivot 96, will cause greater movement downwardly of the fuse and its terminal cap 56 than of contact lever 86. This action may be further enhanced by causing backing strip 28 of contact asser'nbly 28 to be stressed a greater amount than 'the backing strip of contact assembly I8 so that contact lever has engagement with connecting wall I6 of supporting link I2, so that continued movement of the door and fuse assembly with supporting link I2 in a counter-clockwise direction about pivot pins 82 under the push given these parts by the force exerted by contact assemblies I8 and 28, will forcibly move contact portion 82 of contact lever 86 from engagement with contact assembly 28. This will not take a great deal of force because in this position of the parts, contact assembly 28 has substantially assumed its normal position so that little force is exerted thereby against contact lever 86. When the fuse blows, of course, contact lever 86 is no longer maintained in the position shown in Fi 1, so that the contact lever may pivot with supporting link I2 about its pivot pin 88 an amount sufilcient to clear locking lug H8, and thereafter contact lever 86 will move relative to supporting link I2 about its pivot 86 therewith, because of the frictional engagement of its contact portion 92 with contact assembly 28. This relative movement of contact lever 86 and supporting lever I2 continues, of course, until the parts-reach the position shown in Fig. '2 of the drawings, when the momentum of the door and I fuse assembly and parts moving therewith cause disengagement of the contact lever 86 from contact assembly 28. At the position of the parts shown in Fig. 2, contact assembly 28 no longer exerts any force on contact lever 86, so that there is no frictional resistance to continued movement of the fuse and door.

It will be noted that when the fuse and door have moved to an open position with respect to casing 2 and with respect to the circuit between contact assemblies I8 and 28, the door and fuse assembly will assume a depending position as shown in Fig. 4 of the drawings. In this position, an aperture I28 in the connecting portion 98 of contact lever 86 is exposed, and this aperture has a rounded lower portion, as viewed in Fig. 4, and a narrowed upper portion I22 to present a substantially pear-shaped opening for the reception of a hook stick operating member or the like, which may be inserted in opening I28 to lift the door and fuse assembly upwardly and outwardly to remove notches I8 in the supporting link from pivot pins 82 and detach the door and fuse assembly from the casing without the necessity of manually grasping any of the parts. The particular shape of aperture I28 in contact lever 86 is of advantage in that it permits the insertion of the enlarged end of a hook stick so 7 that when the door and fuse assemblies are lifted surface 63 on the door to cause movement of the door anrl fuse with the supporting link after pre- I determined relative movement of the door and link has caused sumcient downward movement ,and fastened in place by terminal cap 56 andv nut I84, after which the fuse and. door may be again assembled with the casing by lifting it by means of a hook stick inserted in aperture 128 in contactlever 86, to cause slots I. in the supporting link to telescope over pivot pins 82, whereupon by insertion of a hook stick in aperture 44 in projection 42 on the outer side of door 38, the door and fuse assembly may be pivotally moved in a clockwise direction about the pivot pins 82 into closed position with respect to casing 2, and with respect to the circuit connected to contact assemblies I8 and 20. In the attachment and detachment of the fuse and door assembly with respect to casing 2, the locking of supporting link 12 and contact lever 86 to the door 38 by virtueof the inter-engagement of locking projection Ill and locking lug H8 is of particular value in that it prevents undue stress being placed on the fuse link by such attaching or detaching operations and provides a rigid structure by which the assembly may be handled. I

In the embodiment of the invention shown in Fig. 3 of the drawings, it will be noted that relative movement of supporting link I2 and the fuse tube and door is prevented by a relatively rigid strap member I26 secured in position between the fuse tube and door in a manner like rodlike pintle supporting member 86, in that strap I 28 has an intermediate curved portion seated in a slot I24 provided at the inner surface of door .enabling assembly or disassembly of the parts panel 40 intermediate flanges '62 for receiving this portion or strap I26 between the door panel and fuse tube 52. The outer ends of strap I26 are bent inwardly towards each other to overlie a downwardly projecting extension I28 on connecting portion 16 of supporting link I2, to positively secure the link with respect to the door and fuse tube. The projection I28 of the supporting link is provided with an outwardly curved central portion I30 extending through connecting portion I6 as shown in Fig. 6 of the drawings, to enable the link to lie close to fuse tube 52.

Thestrap' I26 for fixedly connecting supporting link I2 to the fuse tube and door assembly ,may be readily applied to a fuse constructed in accordance with this invention merely by removing the fuse tube 52 from the apertures of supporting projections 48 and 50 on the door, inserting strap I26 in slotJ2l, and then replacing the fuse tube. In the operation of this embodiment of the invention, when the fuse blows, the bias exerted by contact assemblies l8 and 20 will obviously be inoperative to cause any movement of supporting link 12, and consequently, the fuse tube and door will remain latched in the position shown in ig. 1 and will' not drop out of the circuit.

By the particular method of assembly of the lower contact and supporting means for the fuse tube and door assembly to these parts, it is also possible to readily assemble in the same manner a means, such as strap I 28, for converting the drop-out fuse structure shown in Figs. 1, 2 and 4 through 8 of the drawings, to a non-dropout form of fuse cutout in the manner shown in Fig. 3.

From the foregoing, it is believed to be readily apparent that the fuse cutout structure herein disclosed is especially adapted to provide for the fuse and door-assembly to drop out of the circuit when the fuse blows, and that this dropout action is' provided by a novel lower fuse ter-' minal and support assembl under the bias exerted by line contacts. Furthermore, the dropout action of the fuse of this invention acts to pull out thelower fuse link terminal and iso-.

late the fuse and door assembly from both line contacts so that the assembly will 'be entirely electrically isolated. Ther has also been herein 75 without the use of any tools whatsoever and in' an extremely easy and eiiicient manner. Furthermore, there has also been disclosed in conto the fuse holder terminals with which it is assembled. The latter feature is especially important in fuses of the dropout type because the means exerting a biasing action on the fuse to cause it to drop out of the circuit when the fuse blows is usually opposed by the fuse link itself, thereby placing a certain amount of tension on the fuse link, so that any additional tension placed thereon in assembling it in a fuse holder may readily cause impairment of the link so that it will not operate properly.

Having described preferred embodiments of the invention in accordance with the patent statutes, it is desired that the invention be interpreted as broadly as possible, and that it be not limited to the particular embodiments disclosed inasmuch as it will be obvious, particularly to persons skilled in the art, that many modifications and changes may be made in these particular embodiments without departing from'the broad spirit and scope of the invention. Accordingly, it is desired that the invention be interpreted as broadly as possible and that it be limited only by what is expressly set forth in the following claims and by the prior art.

I claim as my invention:

1. In a fuse, spaced line contacts, a fuse holder, a fuse link in said holder, a support, means mounting said holder on said support for movement into and out of engagement with at least one of said contacts, latch means for maintaining said holder in closed circuit position with respect to said contacts, said mounting means ineluding a supporting link pivoted to said holder and to said support, means secured to said fuse link and engageable with said supporting link and a part movable with said holder for locking said supporting link against movement with re= spect to said holder, whereby to release said supporting link for movement relative to said holder and permit movement of said holder out of en- Basement with said latch means and with at least said one contact when said fuse link blows 2. In a fuse, spaced line contacts, a fuse holdment relative to said holder and permit movement of said holder out of engagement with said latch means and with at least said one contact when said fuse link blows.

' 3. In a fuse, vertically spaced line contacts, a fuse tube having a terminal adjacent the upper end thereof, a fuse link in said tube having one end thereof connected to said terminal, a combined tube terminal and supporting assembly for the lower end of said tube adapted to support said tube for movement of the terminals thereof into and out of engagement with said contacts, latch means for maintaining said tube terminals in engagement with said contacts, said assembly including a pivoted supporting link for the lower end of said tube, and a terminal pivoted on said supporting link, the other end of said fuse link being directly connected to said pivoted terminal for maintaining said pivoted terminal in a position to engage one of said contacts and to maintain said supporting link in a predetermined supporting position relative to said tube, whereby to release said supporting link for movement relative to said tube when said fuse blows to release said tube from said latch means and permit movement of the tube and terminals out of engagement with said contacts.

4. In a fuse, vertically spaced resilient line contacts, a fuse tube having a terminal adjacent the upper end thereof, a fuse link in said tube having one end thereof connected to said terminal, a combined tube terminal and supporting assembly for the lower end of said tube adapted to support said tube for movement of the terminals thereof into and out of engagement with said contacts, latch means for maintaining said tube terminals in engagement with said contacts, said assembly including a pivoted supporting link for the lower end of said tube, aterminal pivotedon said supporting link,the' other end of said fuse link being directly connected to said pivoted terminal for maintaining said pivoted terminal in a position to engage one of said contacts and to maintain said supporting link in a predetermined supporting position relative to said tube, said tube and supporting link constituting a toggle maintained by said fuse link adjacent its dead-center position, both of said tube terminals adapted to slidably engage lower surfaces of said contacts at least .when moved into engagement to obtain pressure wiping contact and to exert a force substantially longitudinally of said tube in a direction to break said toggle,

including a link pivotally connected to a supporting base and 'said assembly at spaced points, terminal means pivotally mounted on said link, a fuse link mounted in said tube and directly engaging said terminal means to normally maintain said terminal means and link in a predetermined position relative to said assembly so that said terminal means is adapted to engage said contact, and latch means engageable with said assembly to maintain said terminal means and contact in engagement, whereby when said fuse blows said link is released for movement relative to said tube to disengage said latch means and move said terminal means out bf engagement with said contact.

6. In a fuse, a resilient line contact a fuse tube assembly, means supporting said tube assembly for movement toward and away from said contact including a link pivotally connected to a supporting base and said assembly at spaced points, terminal means pivotally mounted on linkage, means under the control of said fuse ,link for locking said supporting linkage against said link, a fuse link mounted in said tube and directly engaging said terminal means to normally maintain said terminal meansand link in a predetermined position relative to said "assembly so that said terminal means is adapted to movement toward and-away from said contact in-' cluding a link pivotally connected to a supporting base and said assembly at spaced points, terminal means pivotally mounted on said link, a fuse link' mounted-in said tube and directly engaging said terminal means to normally maintain said terminal means and link in a predetermined position relative to said assembly so that said terminal means is adapted to engage and stress said contact, and latch means engageable with said assembly to maintain said terminal means and contact 'in engagement, whereby when said fuse blows said link is released for movement relative to said tube todisengage said latch means while said terminal means and contact remain in engagement, and to thereafter move said terminal means away from said contact, and said terminal means pivot being spaced from said spaced points so that said stressed contact is effective to cause said movements when said .fuse

blows.

8. In a fuse, .a resilient contact, a fuse tube assembly, means supporting said tube for movement toward and away from said contact including a link pivotally connected to a supporting base and said assembly at spaced points, terminal means pivotally mounted on said link, a fuse link r mounted in said tube and directly engaging said. terminal means to normally maintain said terminal means and link in a predetermined position relative to said assembly s'o that-said terminal means is adapted to engage and stress said contact, means on said assembly engageable by a portion of said terminal means for-positively preventing movement of said link and terminal means when in said predetermined position, and latch means engageable with said assembly to maintain said terminal means and contact in engagement, whereby when said fuse blows said assembly, terminal means and linkare freed for relative movement to disengage said assembly from said latch means.

9. In a fuse, spaced line contacts, a fuseholder, a fuse link in said holder, means mounting said holder for movement into and out of engagement with at least one of said contacts, latch means for maintaining said holder in closed circuit position with respect to said contacts, said mountingmeans including a pivoted supporting movement with respect to said holder, whereby to release said supporting linkage for movement relative to said holder and permit movement of said fuse links blow, and said linkage including an apertured part positioned to. be exposed upon assembly,

movement of said holder out of engagement for the reception of a hook stick or the like.

10. In a fuse, spaced line contacts, a fuse holder, a fuse link in said holder, means mounting said holder for movement into and out of engagement with at least one of said contacts, latch means for maintaining said holder in closed circuit position with respect to said contacts, said mounting means including a pivoted supporting link, pivoted latch means under the control of said fuse link for locking said supporting link against movement with respect to said holder, whereby to release said supporting link for movement out of engagement with said latch means and with at least said one contact when said fuse link blows, said pivoted latch means including an apertured part for the reception of a hook stick or the like.

11. In a fuse, a resilient line contact, a fuse tube assembly, means supporting said tube for movement. toward and away from said contact including a link pivotally connected to a supporting base and said assembly at spaced points, ter-' minal means pivotally mounted on said link, a fuse link mounted in said tube and directly engaging said terminal means to normally maintain said terminal means and supporting link in a predetermined position relative to said assembly so that said terminal means is adapted to 1 engage and stress said contact, latch means engageable with said assembly to maintain said terminal means and contact in engagement, whereby when said fuse blows said link is released formovement relative to said tube to disengage said latch means while said terminal means and contact remain in engagement, and to thereafter move said terminal means away from said contact, and means limiting relative movement of said assembly, supporting link and terminal means to an amount sufficient to release said assembly from said latch means, whereby after such relative movement said assembly and terminal means are adapted to move pivotally with said supporting link away from said contact. 12. In an enclosed fuse cutout construction, a housing having spaced contacts therein, a door and fuse assembly for said housing, cooperating pivot means in said housing and on said assembly for mounting said assembly for movement to and from a position in which said door closes said housing and said fuse is in bridging relation with said contacts, said pivot means constructed to be freely separable only in an open position of said means on the outer side of said door providing an aperture for the reception of a hook stick or the like, the portion of said cooperating pivot means on said assembly mounted on a lever pivoted with said assembly, terminal means pivotally mounted on said lever for engaging one of said contacts, and said terminal means located at the inner side of said door and apertured for the reception of a hook stick or the like to remove said assembly from said housing in an open position thereof.

13. In an enclosed fuse cutout construction, a housing having spaced contacts therein, a door and fuse assembly for said housing, cooperating pivot means in said housing and on said assembly for mounting said assembly for movement to and from a position in which saiddoor closes said housing and said fuse is in bridging relation with said contacts, said pivot means constructed to. be freely separable only in an openposition of said-assembly, means on the outer side of said door providing an aperture for the reception of a hook stick or the like, and means forming a part of said assembly at the inner side of said door provided with an aperture also fo the reception of a hook stick or the like to facilitate detachment of said assembly from said housing in an open position thereof.

14. In a fuse, vertically spaced line contacts, a fuse tube having a terminal adjacent the upper end thereof, a fuse link in said tube having one end thereof connected to said terminal, a combined tube terminal and supporting assembly for the lower end of said tube adapted to support said tube for movement of the terminals thereof into and out of engagement with said contacts, latch means for maintaining said tube terminals in engagement with said contacts, the other end of said fuse link connected to said terminal assembly, said assembly including a pivoted supporting link for said tube, and means preventing relative movement of said link when said fuse blows to maintain said tube terminals latched in engagement with said contacts.

15. In a door and fuse assembly for an enlclosed fuse cutout, a housing door member having spaced laterally extending apertured supporting portions for receiving'a fuse tube member, supporting means for said assembly having a part extending between said door and tube members, said part seated in a groove in at least one of said members, said part retained in said groove by the other of said members, and said supporting means being otherwise unsecured to said members whereby said supporting means is freely removable upon removal of said fuse tube member from said door member.

16. In a door and fuse assembly for an enclosed fuse cutout, a housing door member, a fuse tube member, means detachably securing said members together, supporting means for said assembly having a part extending between said door and tube members, said part seated in a groove in at leastone of said members, said part retained in said groove by the other of said members, and said supporting means being otherwise unsecured to said members whereby said supporting means is freely removable upon removal of said fuse tube member from said door member.

17. In a door and fuse assembly for an enclosed fuse cutout, a housing door member, a fuse tube member, means detachably securing said members together, supporting means for said assembly having a part extending between said door and tube members, said part seated in a groove in at least one of said members, said part and groove being configurated so as to prevent relative endwise movement thereof, said part retained in said groove by the other of said members, and said supporting means being otherwise unsecured to said members whereby said supporting means is freely removable upon removal of said fuse tube member from said door member.

18. In an enclosed fuse cutout door and fuse assembly, a housing door member, a fuse tube member, means detachably-securing said members together, terminal means for said assembly secured thereto by a part extending between said door and tube members, said part seated in a groove in at least one of said members, said part retained in said groove by the other of said members, and said supporting means being otherwise unsecured to said members whereby said supporting means is freely refrom said door membe said door and tube members and seated in a groove in at least one of said members, said-part and supporting means pivotally associated, and means having a portion adapted to-be positioned between said members and seated in a groove in one of said members for engaging said supporting means to prevent pivotal movement therof.

20. In a fuse, vertically spaced resilient line contacts, a fuse tube having a terminal adjacent the upper end thereof, a fuse link in said tube having one end thereof connected to said terminal, a combined tube terminal and supporting assembly for the lower end of said tube adapted to support said tube for movement of the terminals thereof into and out of engagement with said contacts, latch meains for maintaining said tube terminals in engagement with said contacts, said assembly including a pivoted supporting link for the lower end of said tube, and a terminal pivoted on-said supporting link, [the other end of said fuse link nals adapted to slidably engage lower surfaces of said contacts at least when moved into engagement to obtain pressure wiping contact and to exert a force substantially longitudinally of said tube, and in a direction to break said tog gle, whereby'to release said supporting link for movement relative to said tube when said fuse blows to release said tube from said latch means and permit movement of the tube and terminals out of engagement with said contacts and said pivoted terminal adapted to stress its respective contact when moved into engagement therewith an amount such that said contact for said pivoted terminal is efiective upon blowing of the fuse, to exert force on said terminal in a direction to cause movement of said tube away from, said contacts even after disengagement of said tube and latch means.

21. In a dropout fuse, spaced resilient line contacts, a fuse .tube having a terminal, supporting linkage for said tube including a pivoted supporting lever, a terminal lever pivoted on said supporting lever, a fuse link connecting said terminal and terminal lever for maintaining said levers in one position wherein said terpivoted supporting link and an auxiliary link pivoted on said main link, and said auxiliary link directly connected to said fuse link, whereby to release said linkage for relative movement and permit movement of said holder out of engagement with said latch means and with at least said one contact when said fuse link blows.

23. In a dropout fuse, spaced resilient line contacts, a supporting lever, a pair of members each having a terminal portion, each of said members pivoted on said lever at spaced points for movement relative to said lever and relative to each other and adapted to engage and bias said contacts in a manner such that each of said contacts exerts a force on its respective terminal in a direction to cause movement of said lever in one direction to move said terminals out of engagement with said contacts, and means including fusible means connecting said tenninals to normally prevent movement of said lever in said one direction.

positionrelative to said assembly so thatsaid terminal 'means is adapted to engage said contact, means on said assembly engageable by a portion of said terminal means for positively preventing movement of said link and terminal means when in said predetermined position, and

latch means engageable with said assembly to maintain said terminal means and contact in engagement, whereby when said fuse blows said assembly, terminal means and link are freed for relative-movement to disengage said assembly from said latch means.

25. In a fuse, spaced line contacts, a fuse holder, a fuse link in said holder, means mounting said holder for movement into and out of engagement with at least one of said contacts, latch means for maintaining said holder in closed circuit position with respect to said contacts, said mounting means including a supporting link pivoted on said holder and on a support, cooperating latch means on said link and a part fixed with respect to said holder, one part of said latch means being movably mounted and secured to said fuse link for lockminal and terminal lever are engaged with said contacts, respectively, and .wherein said levers form with said fuse tube toggle means adjacentv dead-center position, with the force exerted by said resilient contacts acting in a direction to break said toggle means and .cause movement of said fuse terminals away from said contacts.

22. In a fuse, spaced line contacts, a fuse holder, a fuse link in said holder, means mounting said holder for movement into and out of engagement with at last one of said contacts, latch means for maintaining said holder in closed circuit position with respect to said contacts said mounting means including a main ing said supporting link against movement with respect to said holder, whereby to release said supporting link for movement relative to said holder and permit movement of said holder out of engagement with said latch means and with at least said one contact when said fuse link blows.

26. In a fuse, spaced line contacts, a fuse holder, a fuse link in said holder, means mounting said holder for movement into and out of engagement with at least one of said contacts, latch means for maintaining said holder in closed circuit position with respect to said contacts, said mounting means including a pivoted supporting linkage, means under the control of said fuse link for maintaining said supporting linkage against movement with respect to said holder, whereby to release said supporting linkage for movement relative to said holder and permit movement of said holder out of engagement with said latch means and with at least said one contact when said fuse links blow, and said linkage including an apertured part positioned to be exposed uponsaid movement-of said holder out of engagement for the-receptionof said housing and said fuse is in bridging relation with said contacts, said pivot means constructed to be freely separable only,in an open position of said assembly, and means mounted on said door at the inner side thereofprovided with; an aperture for the reception of a hookstick or the like to facilitate detachment of said assembly from said housing in an open position thereof with said aperture located in a plane substantially parallel to the plane of said door.

28. In an enclosed fuse cutout door and fuse assembly, a housing door member, a fuse tube 31. In a dropout fuse, spaced resilient line contacts, a fuse tube having a terminal, supporting means for said tube including a supporting lever pivoted to said tube and. to a support, a terminal lever pivoted. on said supporting means adjacent dead-center position, with the member, means detachably securing said members together, supporting means for said assembly including a supporting link pivoted. on said assembly, means connecting said link and assembly for preventing relative movement thereof, said connecting means maintained in operative position by .a 'part thereof extending, between said members with said part maintained in a groove formed in one of said members by the other of said members.

29. In a drop-out fuse,, spaced resilient line contacts, a fuse tube having. a terminal, supportsupporting link, a terminal lever pivoted on said link, a fuselink connecting said terminal and terminal lever for maintaining said linkage in one position wherein said terminal and terminal lever are engaged with said contacts, respectively, and wherein said link and fuse"- tube-form toggle means positioned adjacent dead-center at said one position of said linkage, and the force exerted by said resilient contacts acting in a direction to break said toggle means and cause movement of said fuse terminals away from said contacts.

30. In a drop-out fuse, spaced resilient line contacts, a pivoted supporting lever, separate cause movement of said lever inone direction to move said terminals out of engagement with said contacts, and means including fusible means connecting said terminals to normally prevent movement of said lever in said one direction.

lever, a fuse link connecting said terminal and terminal lever for maintaining-saidlevers in one position wherein said terminal and terminal lever are engaged with said contacts, respectively, said 10 supporting lever and tube forming toggle means between said support and one line contact, said two levers forming toggle means between said support and the other of said contacts, said fuse link normally maintaining both of said toggle force exerted by said resilient contacts acting f in a direction to break said toggle means'and cause movement of said fuse terminals away fromv said contacts.

tube assembly, means supporting said tube assembly for movement toward and away from said contact including a link pivotally connected to a supporting and said assembly at spaced points, terminal means mounted on said link for limited pivotalmoveme'nt relative to said link, a fuse link mounted in said tube and directly engaging said terminal means to normally maintainlsaid terminal means and link in a predetermined position relative to said assembly so that said terminal means is adapted to engage and stress said'contact, and latch means engageable with said assembly to maintain said terminal means and contact in engagement,

whereby when said fu'se blows said linkis reing linkage for said tube including a pivoted leased for movementrelative to s'aid'tube to dis:

engage 'said latch means while said terminalmeans and contact remain in engagement by virtue of relative movement of said terminal ing said holder for movement into and out of fuse link for locking said supporting linkage .tive movement said terminal means is moved away from said contact. v

33. In alfu'se, spaced line contacts, a fuse holder, a fuse-link in said holder, means mountengagement with at least one of said contacts, latch means for maintaining said holder in closed circuit position with respect to said contacts, said mounting means" including a pivoted supporting linkage, means under-the control of said against movement with respect to said holder, whereby to release said supporting linkage for movement relative to said holder and permit movement of said holder out of engagement contact when said fuse links -.with said latch means-and withat least said one blow.

32. In a fuse, a resilient line contact, a fuse HERBERT IL. mwims'. v

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