US2179759A - Fuse - Google Patents

Description

NOV. 14, 1939- w. o. SCHULTZ FUSE Filed Jan. 9, 1933 2 Sheets-Sheet 1 INVENTOR m/Am a Jfifi/ig Q2 i ATTORN Y Patented Nov. 14, 1939 UNITED STATES PATENT OFFICE ruse William 0. Schultz, South Milwaukeq wisq as signor to Line Material Company, South Milwaukee, Win, a corporation of Delaware Application January 9, 1933, Serial No. 650,815

50 Claims. (Cl. 200-114) drops out of position, or, in other words, moves away from the live contacts when the fuse blows, the invention providing an expulsion type of fuse which is housed but which nevertheless actually disconnects both ends of the fuse assembly from the live contacts, so that the entire fuse assemlily is dead, the invention providing means whereby there are no live parts projecting outside of the housing when the fuse has blown.

In still greater detail objects of this invention are to provide a housed type of drop-out fuse in which the fuse assembly'and the cover to the housing arehinged adjacent the lower portion of the fuse structure, in which'the blowing of the fuse automatically releases the lower portion of the fuse and allows such portion and the door'to first move outwardly and thereafter allows boththe fuse and the door to slide downwardly and rock outwardly 'clearof' the housing, the invention providing means whereby the lower hinge is dead or disconnected from all-portions of the. line after the fuse has blown.

Further objects are-to provide a construction of enclosed drop-out'fuse' in which'the fuse and door may be removed as ,a single unit and may be replaced by merely hooking-them into the lower hinge, in which means are provided whereby the door, together with the fuse, may be openedeven though the fuse is not blown, in which the door, together with the fuse assembly, may be readily rocked back into position, both the opening and the closing of the apparatus being freely accomplished by means of a doorring so that a lineman or attendant may operate the fuse with a fuse pole, and in which means are provided for cushioning the moving portions at the lower part of their swing so that excessive strains are not produced. I

-This invention has for its further objects the provision of means which insures the complete blowing of the fuse before the contacts are opened so that there is noarclng at the contacts, the

interruption of the circuit always occurring inside the fuse tube by the blowing and expulsion action to a section on the line 5-5 of Figure 4.

thereof, thereby avoiding burning or pitting of the contacts or other destruction of the permanent portions of the fuse.

Further objects of this invention are to provide a fuse construction which operates .jon light overa load conditions as well as on heavy overload conditions, the invention providing means whereby a roughly predetermined interval of time eiapses before the actual permanent contacts are broken, thereby allowing time for the fuse to build up sufllcient pressure in the tube to give the empulsion action necessary to extinguish the are,

and confining the actual rupturing of the circuit in the first instance to the interior of the tube, means being provided to insure contact between the contacts of the fuse and vtheterminal contacts or stationary contacts for a material portion of the swing of the fuse, thereby securing the interval of time hereinabove referred to.

Further objects are to provide a housed type of drop-out fuse which may be as readily and freely handled as the usual housed type fuses, which may be easily re-fused, and which is of simple and reliable "construction.

Embodiments of the invention are shown in the accompanying drawings, in which:

Figure 1 is a vertical sectional view showing the fuse in closed position in full lines and showing in dotted lines successive positions occupied by the,parts during the opening of the fuse.

. Figure 2 is a side view of the structure showing the usual angle at which it is mounted.

Figure 3 is a sectional view on the line 3-3 of Figure 1.

Figure 4 is a'sectional view on the' line H of Figure 1.

Figure 5 is a fragmentary detail corresponding Figure 6 is a view, partly broken away and partly in section, of the fuse assembly. A I Figure '1 is a sectional view through the upper portion of a modified form of the fuse. Referring to the drawings, it will be seen that the fuse housing or casing, which is preferably of porcelain, is indicated by the reference character]. 4 door 2 is formed of insulating material and is provided with a door ring 3 by means of which the door may be pulled open either by the hand of a lineman or -.by a fuse pole provided with the usual-hook. It is preferable to construct these doors of a phenol condensate product commonly known as "Bakelite".

The door is provided with a bracket 4 having outstanding spaced ears between which the lower.

is pivotally mounted, as indicated at l. The fuse tube is provided with an upper contact 8 which is received between the U-shaped spring arms 9 of a contact member carried by the upper portion of the door, as shown most clearly in Figure 3.

The fuse tube is shown in greatest detail in Figure 6. In accordance with ,the usual practice, the upper contact is provided with a cap or ring nut in which clamps the upper disk H of the expulsion fuse link in place. This expulsion fuse link is provided with a reduced upper portion i2 and a flexible portion or leader 13 which extends downwardly and is looped around the bottom end of the fuse tube. It is received and clamped to a contact lever M by means of a thumb screw 95,

or in any other suitable manner. The upper end of the lever i4 is bifurcated and is pivoted, as indicated at 16, to the lower contact 5. It is to be noted that this lower contact 5 has a rearwardly I projecting lip H which limits the outward rocking motion of the lever M, as is obvious from an inspection of Figures 1 and 6 and for a purpose hereinafter to appear.

It is to be noted from Figures 1 and 6 that the lever M is provided with lower outwardly projecting spaced feet or arms l8 which are 10-- catecl on opposite sides of the lower portion of the fuse tube. These feet are provided with rubber bumpers or other resilient bumpers, as indicated at 59, which are adapted to contact with the lower portion of the housing I when the door and fuse tube swing outwardly into their final position.

The fuse tube 5 is urged to rock in a clockwise direction, as viewed in Figure 1, by means of a spring 26, see Figure l, which bears against the lower end of the fuse tube, such spring having its upper end rigidly secured to the door preferably by the same screwsthat hold the bracket 5 in place. The upperend of the fuse, therefore, has a slight amount of motion but is urged towards the doorin the normal position, as shown in Figure 1;

The housing is provided with an upper terminal member 2| and a lower terminal member 22. The upper member is provided with brush type or spring contacts 23 which bear against the upper contact 8 of the fuse. The lower terminal member 22 is similarly provided with brush contacts or spring contacts 24 which bear against the flat rear face of the lever 14. Also it will be noted from Figure 1, the lower terminal member 22 is provided with a follow through contact 25 which may take the form of a springlike member and which bears against the thumb nut or thumb screw I5. This follow through contact 25 maintains contact with the lower electrically active portion of the fuse assembly for a slightly greater length of time than the brush contact 24 whenthe fuse drops open.

The upper terminal member is provided with a pair of outwardly projecting jaws 26 formed in the shape of a U, as shown most .clearly in Figure 3. 'I'hese jaws are preferably outwardly turned at their extreme outer ends, as shown in Figure 3, and are provided with downwardly extending portions 21, see Figure 1, which have outwardly and downwardly slanting inner cam faces 28 behind which the outwardly projecting pins 29 of the upper contact 8 are normally positioned, as shown in Figures 1 and 3.

llhe fuse assembly and door are secured by a lower hinge construction. The lever i4 is provided' with outwardly projecting pins or trunnions 30, see Figures 1 and 4, which fit within the hooked end of the hinges 3| carried by the casing l. The hinge is free from electrical connection with the lower terminal member 22, as is obvious from Figures 1 and 5, and when ,the 5 fuse is opened, the hinge is dead. 7

The lever 14 is normallyaheld against the fuse tube in the position shown in Figures 1 and 6, by means of the fuse link. It is to be noted that the leader l3 of the fuse link extends outwardly 10 and loops around the bottom of the fuse tube and the end of the lever l4, thus normally holding the lever M in the position shown in Figure 1 while the fuse link is intact. However, when the fuse blows, the level-J4 is released and may rock outwardly away from the fuse tube, thus,allowing the fuse assembly and door,to rock outwardly adjacent their lower ends, as indicated in the upper dotted line position of. Figure 1- When the fuse assembly and door rock to this position, it is obvious that the parts may then pivot about the lower hinge pins or trunnions 30 and rock to their final position'shown in-Figure 1.

It is to be noted particularly that the first portion of the travel of the parts occupies a certain interval of time and insures the complete rupturing of the circuit within the fuse tube prior to the breaking of either the upper or lower contacts, the follow through contact member 25 carried by the lower terminal member prolonging the engagement of the lower contacts for a material portion of the swing of the fuse door and fuse assembly.

It is to be noted that at the upper end of the device that the pins 29 ride downwardly and outwardly along the cam faces 28 of the upper looking member, and that the brush contact 23 maintains a good electrical contact with the upper contact 8 of the fuse assembly during this portion of the motion of the parts.

. It has been found that this construction allows an interval corresponding to several cycles of an ordinary GO-cycle current before the contacts are broken at the upper and lower portion of the fuse assembly, thereby allowing complete expulsion and clearing of the fuse link so that the actual rupturing of the circuit is confined to the interior of the tube and arcing at the contacts cannot occur.

It is to be noted also that the brush contacts tend to push the movable parts outwardly to initiate the outward swinging of the parts. This functioning is particularly desirable in light overloads so as to give the fuse time to build up sufficient pressure Within the tube to insure expulsion of the link and extinguishing of the are within the tube prior to the actual mechanical separation of the upper and lower contacts of the fuse assembly from the terminal members.

It is sometimes desirable to open the fuse while 30 the fuse link is still intact. This is readily accomplished by providing the spring jaws 9 or holding jaws at the upper portion of the door, see particularly Figure 3, with outwardly pro-' jecting cam portions 32. These outwardly pro- 5 lecting portions are normally located inwardly of the extensions 21 of the upper holding member or bracket 26 carried by the casing I, as shown in Figures 1 and '3. However, when the door is pulled outwardly adjacent its upper end by means of the door ring 3, it is obvious that the pins 29 will rest behind the extensions 21, contacting with the faces 28 thereof. However, in view of the fact that the fuse assembly is pivoted, as indicated at 1, it is obvious that the door will rock 76 about such pivot point a slight amount contrary to the action of the spring 10, and that the outwardly projecting cam portions 32 of the arms 0, see Figure 3, will slide betweeuthe extensions 21 and will spring such, extensions outwardly, the arms 26 being springy and freely movable.

These arms are, therefore, sprung outwardly sufllcient for the pins 28 to clear and to pass between the extensions 21, thereby permitting the opening of the apparatus.

when the door is in its fully openedposition, as shown in the lower dotted line position in Figure 1, either by the blowing of the fuse or by being manually pulled open when the fuse link is intact, the lower hinge ii is dead and disconnected, as it is wholly disconnected from all live portions of the line. The door and fuse assembly may be readily removed by merely unhooking the lower pins II from the hinge II.

It. is to be noted from Figure 3 that the cam members I! are in reality double cam members,

that is to say, they have a slanting face presented both forwardly and rearwardly. This construction enables the door to be easily closed, the cam members 32 riding between the projections 21 and springing the arms 26 apart during the closing of the door, thereby allowing the pins 29 to readily pass to the position shown in Figures 1 and 3. v

In the form of the invention shown in Figure 7, the same general idea is followed. However, the upper terminal member 33 is provided with a downwardly pressed channel-shaped lever 34 which is itself provided with an aperture 35. The upper contact 36- of the fuse tube is engaged by the brush contacts 31 of the upper terminal member. The upper contact is provided with a cap or nut 38 which has an upwardly projecting pin 39 normally positioned within the aperture of the lever M.

The door is provided with a forked bracket 40 between which the upper contact 36 is loosely positioned. This bracket 40 is provided with upturned ends 4| which engage the cam shaped downwardly projecting portions 42 of the lever is and raise such lever to free the pin .39 both in the opening and closing motion of the door. It is preferable to provide the lover I with an upwardly projecting cam portion 4'! so that the pin as may freely ride beneath such portion during the closing motion of the door.

In other respects the construction'is similar to that shown in Figure l. The fuse tube is secured at its lower end in exactly the same manner as shown in Figure 1. g,

It will be seen that a housed type of drop-out fuse has been provided by this invention in which both the advantages of the housed type fuse and also the advantages of the drop-out fuse are lobtained.

3. 'It will be seen further that the construction is very simple, is easily produced, and that the de vice is ,reliable in operation.

It is, of course, apparent that by having the upper end of the fuse tube closed, as shown, that, l

on the one hand, moisture cannot enter the fuse tube from the upper end and further the highly conducting ga es formed by the volatilization of the fuse link are not projected into the housing and consequently do not form a conducting me--' dium between the stationary contacts mounted .within the housing, as would otherwise be the case.

Although this invention has been described in considerable detail. it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim: 1. A housed type drop-out fuse comprising a casing, a door for said casing, a fuse assemblycar-- ried by said door, pivot means supporting said door and fuse assembly, said fuse assembly having a fuse link, and means releasably holding said door closed, said means being normally restrained against releasing movement by said fuse.

link and being released when said fuse link is ruptured.

2. A housed type of drop-out fuse comprising a casing having spaced contacts, a door for said casing, a fuse assembly carried by said door and having spaced contacts, a fuse link forming a portion of said fuse assembly, means releasably holding said door closed and holding the contacts of said fuse assembly -in engagement with the contacts of said casing, said means includ ing hinge means hinged with relation to said casing for guiding the lower portion of said .door bodily away from said casing when the dor and fuse assembly are released, said means additionally allowing said door and fuse assembly to rock outwardly with respect to said casing, said fuse link holding said means againstreleasing.

A housed type of drop-out fuse comprising a casng, stationary contacts carried by said casing, a door for said casing, an expulsion fuse tube carried by said door and having contacts engaging said stationary contacts when said door is closed, said expulsion fuse having a closed upper end and having an open lower end, a fuse link a casing, stationary contacts carried by said casing, a door for said casing, an expulsion fuse for said door comprising a tube having an open lower end and a closed upper end and having spaced contacts normally engaging the stationary contacts and having a lnk normally joining said spaced contacts and extending outwardly from the lower open end of said fuse tube, means pivotally supporting said door and said expulsion fuse, said casing having an open bottom adjacent the open lower end of said tube,-and latching mechanism for said door-controlled by said fuse link and releasable when said fuse link blows.

, whereby said door and said expulsion fuse will rock outwardly awayfrom said casing after saidfuse blows. .r

5. A housed type of drop-out fuse comprising a casing, stationary contacts carried by said casing. a door normally closing said casing and adapted to wing outwardly away from. said casing, releasable latching means for holding said 'door closed, supporting means pivotally supporting said door adjacent its lower end and releascable and-guiding the lower end of said door away from said casing and additionally allowing said door-to pivot with reference to said casing, an

expuP'ion fuse carried by said door, and a link forming a portion of said expulsion fuse and holding said -latching means against releasing movement, ,whereby when saidqfiise link is expelled, said door is released and swings outwardly away from said casing,'said expulsion fuse also rocking outwardly away from said stationary contacts.

6. A housed type of drop-out fuse comprising a casing, stationary contacts carried by said casing, a door for said casing, an expulsion fuse carried by said door and having spaced contacts engaging said stationary contacts and having a fuse link normally joining said spaced contacts, lever mechanism. for supporting said door and expulsion fuse adjacent the lower end thereof and restrained against motion by said fuse link, and latching means adjacent the upper portion of said casing for holding the upper end of said door closed, saidilever mechanism when released by the expulsion of said fuse link first rocking the lower end of said door and expulsion fuse outwardly, said door and expulsion fuse thereafter moving downwardly and rocking outwardly from said casing.

7. A housed type of drop-out fuse comprising a casing having stationary contacts, a unitary assembly of expulsion fuse and a door, said assembly being pivotally carried by link mechanism adjacent the lower portion thereof, said link mechanism being held in its normal position by a fuse link forming a portion of said expulsion fuse and being adapted to rock said assembly outwardly when said expulsion fuse is ruptured, and latching means for the upper portion of said assembly, said latching means being released when the lower portion of said assembly rocks outwardly, whereby said assembly first rocks outwardly adjacent its lower end and thereafter bodily moves downwardly upon the rupturing of said fuse link.

8. A housed type of drop-out fuse comprising a casing having stationary contacts, a unitary assembly of expulsion fuse and a door, said assembly being pivotally carried by link mechanism adjacent the lower portion thereof, said link mechanism being held in its normal position by a fuse link forming a portion of said expulsion fuse and being adapted to rocksaid assembly outwardly when said expulsion fuse is ruptured, and

' latching means for the upperportion of said as sembly, said'latching means being released when the lower portion of said assembly rocks outwardly, whereby said assembly first rocks outwardly adjacent its lower end and thereafter bodily moves downwardly upon the rupturing of said fuse link, the electrical engagement between the contacts of said casing and the contacts of said expulsion fuse being maintained throughout a material portion of the travel of said assembly.

9. A housed typeof drop-out fuse comprising a casing having stationary contacts, a unitary assembly of a door and an expulsion fuse, a link pivotally joining the lower portion of said assembly with the lower portion of said casing, said link normally occupying a position adjacent said expulsion fuse and being restrained from motion by a fuse link forming a portion of said expulsion fuse, spaced. contacts carried by said expulsion fuse and normally electrically connected to said stationary contacts, a latch mechanism adjacent the upper end of said casing for temporarily holding said assembly in closed position with respect to said casing, said stationary contacts being yielding and maintaining engagement with the contacts of said expulsion fuse for a material portion of the movement of saidrassembly after said fuse link blows, whereby arcing at the contacts is prevented.

10. A housed type of drop-out fuse bomprising a casing, a door forsaid casing, an expulsion fuse pivotally mounted on said casing and having a lower contact and an upper contact, said upper contact being provided with projecting means, a fuse link electrically joining said contacts, a latch means carried by said casing and normally engaging said projecting means, and mechanism for holding said projecting means in engagement with said latch means and movable to disengaging position, said mechanism being retstrained against motion by said fuse link, and releasing means carried by said door for releasing said latch mechanism when said door is forcibly pulled outwardly adjacent its upper end.

11. A housed type of drop-out fuse comprising a casing, a door for said casing, an expulsion fuse pivotally mounted on said casing and having a lower contact and an upper contact, said upper contact being provided with projecting means, a fuse link electrically joining said contacts, a latch means carried by said casing and normally engaging said projecting means, and mechanism for holding said projecting means in engagement with said latch means and movable to disengaging position, said mechanism being restrained against motion by said fuse link, and releasing means carried by said door for releasing said latch mechanism when said door is forcibly pulled outwardly adjacent its upper end, said releasing means having motion with respect to the upper end of said expulsion fuse during releasing action.

12. A housed type of drop-out fuse comprising a casing, a door for said casing, an expulsion fuse pivotally mounted on said casing and having a lower contact and an upper contact, said upper contact being provided with projecting means, a fuse link electrically joining said contacts, a latch means carried by said casing and normally engaging said projecting means, and mechanism for holding said projecting means in engagement with said latch means and movable to disengaging position, said mechanism being restrained against motion by said fuse link, and releasing means carried by said door for releasing said latch mechanism when said door is forcibly pulled outwardly adjacent its upper end, said releasing means having motion with respect to the upper end .of said expulsion fuse during releasing action, and spring means carried by said door and'tending to hold said expulsion fuse in a predetermined position with respect to said door.

13. A housed type of drop-out fuse comprising a casing, contacts carried by said casing, an expulsion fuse and door assembly for said casing,

' said assembly including an expulsion fuse having spaced contacts engaging the contacts carried by the casing and having a fuse link normally joining said spaced contacts, lever mechanism for supporting said assembly from said casing and restrained against motion by said fuse link, and

. latching means for said assembly for normally holding said assembly in closed position, said lever mechanism when released by the expulsion of said fuse link moving said assembly to open position.

14. A housed type drop-out fuse comprising a casing, contacts carried by said casing, an expulsion fuse and door assembly for said casing, said assembly including an expulsion fuse having spaced contacts normally engaging the contacts carried by said casing and having a fuse link normally joining said spaced contacts, hinge means distinct and separate from the contacts tion and. thereafter the assembly bodily moves carried by said casing for pivotally supporting said assembly, and latch mechanism for said assembly controlled by said fuse link and releasable when said fuse link blows, whereby said assembly,

will move to open position with reference to'said casing when said fuse blows, said hinge means being electrically dead after said fuse blows.

15. A housed type drop-out fuse comprising a casing having contacts, a unitary assembly of an expulsion fuse and a door, said expulsion fuse having spaced contacts normally engaging the contacts carried by said casing, hinge means carried by the lower portion of said casing mechanically distinct from the contacts carried by said the lower portion of said assembly moves towards open position, whereby the lower portion of said, assembly first moves towards open positowards open position upon the rupturing of said fuse link, said hinge means being electrically dead after the rupture of said fuse link and after said assembly has moved to open position.

16. A housed type drop-out fuse comprising a casing, contacts carried by said casing, an expulsion fuse and doorassembly for said casing, said assembly including an expulsion fuse having spaced contacts engaging the contacts carried by the casing and having a fuse link normally join ing said spaced contacts, latching means including lever mechanism for normally holding said assembly in closed position, said fuse link normally restraining said lever mechanism from moving to releasing position, and hinge means for said assembly, said hinge means being mechanically distinct from the contacts carried by said casing and electrically dead after said fuse link has ruptured and said assembly moved to open position.

1'7. A housed drop-out fuse comprising an insulating housing having an open bottom, an open front, and spaced terminals therein; a door for the open front; a fuse cartridge including contacts engageable with the terminals and a fuse link connecting the contacts, a pivotal support means for the tube carried by the housing in spaced relation to the terminals and offset inwardly of the housing relative to the cartridge, whereby movement of the cartridge toward open circuit position will cause the lower end of the cartridge to move downwardly about said pivot, said fuse link being engageable with said support to prevent pivotal movementof the cartridge until said fuse link is severed.

18. A housed dropout fuse comprising an in sulating housing open at the bottom and open at the front, spaced terminals in the housing, a fuse tube having contacts engaged with said terminals, a fuse, link connecting the contacts, a pivot for said tube adjacent the open bottom and spaced from the terminals, meanspivotally connecting the tube with said pivot, said tube being movable relative to said means, whereby to move said tube, endwise relative to at least one of said terminals, and said fuse link being enthe tube relative thereto until the fuse link is sever'ed.

l9. A housed drop-out fuse including an insulating housing open at the bottom and at the front and having contacts, and a fuse cartridge 5 having contacts normally electrically connected to said first mentioned contacts, said fuse cartridge being pivotally mounted in said housing I and movable endwise on said pivot relative to the top of said housing and having a fuse link, said 10 cartridge being restrained by said fuse link when said fuse link is unsevered and, being released by said )fuse link when said fuse link is severed, whereby the cartridge will automatically be electrically disconnected from an electric circuit 15 when said fuse blows. o I

20. In a housed type fuse, an insulating housing open at its front and bottom, ,line terminals in said housing, a fuse cartridge having contacts engaging the terminals and a fuse link connecting the contacts, a pivotin the housingin spaced relation to the terminals and supporting the cartridge,ssaid cartridge beingimovable in a radial direction relative to the pivot axis, and latch means controlled by therfuse link for restraining the cartridge against said radial movement.

21. In a drop-out fuse of the character described, a pair of line terminals spaced from each other by means of an insulating support, a fuse cartridge electrically'connecting said terminals 30 and including a fuse link, a pivot support for the tube carried by the insulating support in spaced door and having contacts normally engaging said stationary contacts, supporting means for pivotally supporting said door and fuse assembly,

said supporting means being mechanically spaced from and being distinct and separate from said stationary contacts, said fuse assembly having a fuse link, and means releasably holding said door closed, said means being normally restrained against releasing motion by said fuse link and being released when said fuse link is ruptured.-

23. In a fuse of the character described a main body portion constituting a support, a pair of line terminals spaced from each other and carried by said main body portion, .a fuse cartridge electrically connecting said terminals and insaid cartridge and movable with respect to said cartridge and with respect to said support, and means supporting said lever, said means being distinct and separate from said line terminals,

' eluding a fuse link, a lever pivotally supporting said fuse link normally holding said lever against 0 rocking with respect to said fuse cartridge and releasing said lever upon blowing of said fuse.

24. In a house d type fuse of the class de scribed, an insulating housing having an open front and bottom, a door for the open front of 5 said housing, a fuse cartridge secured to said door and having its lower end open and adjacent the open bottom of the'housing, a lever pivotally supporting said door and fuse cartridge, said lever having its lower portion pivotally supported by means carried bysaid housing, upper and lower terminals mounted within said housing, a

contact on the upper end of said cartridge cngaging the upper terminal, resilient means elec-r trically connecting the lower of said terminals 78 and said lever, and a fuse link in said :luse cartridge normally establishing electrical connection from the upper to the lower terminal, said fuse link normally restraining said lever against pivotal motion.

25. A fuse construction comprising a-housing having contacts and an open bottom portion, a door for said housing, said door being movably supported from said housing and movable downwardly and outwardly from said housing, means adjacent the upper portion of said door for normally holding said door against motion, an open bottom expulsion type fuse tube carried by said door and movable as a unit with said door, a fuse link within said fuse tube normally electrically joining said contacts, and mechanism controlled by said fuse link and released when said fuse link is ruptured, said mechanism when released allowing said door to move downwardly and outwardly from said housing.

26. In an automatic current interrupting switch, a main body portion, a pair of line terminals spaced from each other and carried by said main body portion, an arcing tube electrically connecting said terminals and including an expulsible conductor, a lever pivotally supporting said tube and movable with respect to said tube and said body portion, means supported by said main body portion in insulated relationship to said terminals and supporting said lever, and

means holding said lever against movement relative to the tube and including current responsive means for releasing said lever when said switch is subjected to an overload.

27. In an automatic current interrupting switch, an insulating housing having an open front and bottom, a door forthe open front said housing, an arcing tube secured to the door and having its lower end open and adjacent the open bottom of the housing, a lever pivotally supporting said door and tube, said lever having its eluding contacts engageable with the terminals lower portion pivotally supported by means carried by the housing, upper and lower terminals mounted within said housing, a contact on the upper end of said tube engaging the upper terminal, resilient means electrically connecting the lower of said terminals and said lever, an expulsible conductor. in said tube normally establishing electrical connection from the upper to the lower terminal including means normally restraining said lever against pivotal motion until said switch is subjected to an overload current.

28. An automatic current interrupting switch comprising a housing having contacts and an open bottom portion, a door for said housing, mechanism movably supporting said door from said housing, said door being movable down wardly and outwardly from said housing, means adjacent the upper portion of said door for nor mally holding said door against motion, an expulsion' type arcing tube carried by said door,

an expulsible conductor within said tube normally electrically joining said contacts, latch mechanism controlled by the conductor, and cur rent responsive means for releasing said conductor and mechanism, said mechanism when released allowing said door to move'downwardly and outwardly from said housing.

29. A. housed drop-out switch comprising insulating housing having an open bottom, an open front, and spaced terminals therein, a door for the front of said housing, an arcing tube inand a conductor connecting the contacts, a i

' eta} supporting means for the tube carrie the, housing in spaced relation to the terminals and offset inwardly of the housing relative to the tube, whereby movement of the tube towards open circuit position will cause the lower end of the tube to move downwardly about said pivot, said conductor being engageable with said support to normally prevent pivotal movement of the arcing tube.

30. A housed drop-out switch comprising an insulating housing open at the bottom and open at the front, spaced terminals in the housing, an arcing tube having contacts engaged with said terminals, an expulsible conductor connecting the contacts, a pivot for said tube adjacent the open bottom and spaced from the terminals, means pivotally conecting the tube with said pivot, said tube being movable relative to said means, whereby to move said tube endwise relative to at least one of said terminals, and current controlled means normally holding said tube relative to said pivotal means.

31. A housed drop-out switch including an insulating housing open at the bottom and at the front and having contacts, an arcing tube having contacts normally electrically connected to said first mentioned contacts, said tube being pivotally mounted in said housing, means guiding said tube for endwise movement relative to the top of said housing and an expulsible conductor within said tube, and current controlled means restraining said tube against piovtal movement until saidswitch is subjected to an overload.

32. In a housed type drop-out switch, an insulating housing open at its front and bottom, line terminals in said housing, an arcing tube having contacts engaging the terminals and an expulsible link connecting the contacts, a pivot in the housing in spaced relation to the terminals and supporting the tube, means guiding said tube for movement in a radial direction relativev to the pivot axis and including restraining means normally restraining said tube against said radial movement, and current responsive means controlling said restraining means.

33. In a drop-out switch of the character described, a pair of line terminals spaced from each other by means of an insulating support, an arcing tube electrically connecting said terminals and including an expulsible conductor, a pivot support for the tube carried by the insulating support in spaced relation to the terminals and insulated therefrom, latch means normally holding the tube in terminal connecting position, and current responsive means for releasing said latch means.

34. A housed type of drop-out switch comprising a casing having stationary contacts, a door for said casing, an arcing tube carried by said door and having contacts normally engaging said stationary'contacts, supporting means for pivotally supporting said door and tube, said supporting means being mechanically spaced from and being distinct and separate from said stationary contacts, said tube having an expulsible conductor, latch means releasably holding said door closed, and current responsive means for controlling said latch means.

35. A housed type of drop-out switch comprising a casing, contacts carried by the casingpan arcing tube and door assembly for said casing,

said assembly including an expulsible flexible conductor and spaced contacts engaging the contacts carried by the casing, lever mechanism for supporting said assembly from said casing and restrained against motion by said conductor, latch means for said assembly normally holding said assembly in closed position, and current vretlon, said conductor having a severable section,

said conductor releasably holding said latch means.

37. A housed'type drop-out switch comprising a casing, contacts carried by said casing, an arcing tube and door assembly for said casing, said assembly including an expulsible flexible conductor having a severable portion, and hinge means supporting said assembly and including current responsive means normally holding said assembly in closed position.

- 38. A fuse switch comprising a housing having upper and lower'resilient contact elements located therein, a door forsaid housing movably supported thereby, a fuse cartridge mounted on said door and adapted to contact with said contact elements, a fuse element associated with said fuse cartridge, latch means adapted to engage said cartridge for retaining the door in a closed position, and means engagedby said fuse element for effecting disengagement of the cartridge and the latch means on rupture of the fuse element so asto permit said door to move to the open position, thereby carrying the fuse cartridge out of the fusing position, said lower resilient contact element including a portion which exerts an outwardly and upwardly directed force against said door.-

39. A fuse switch comprising a housing hav 0 ing upper and lower resilient contact elements located therein, a door for said housing movably supported thereby, a fuse cartridge mounted on said door and adapted to contact with said contact elements, a fuse element associated with said fuse cartridge, latch means adapted to engage said cartridge for retaining the door in a closed position, and means engaged by said fuse element for eifectingdisengagement of the cartridge and the latch means on rupture of the fuse element so as to permit said door to move to the open position, thereby carrying the fuse cartridge out of the fusing position, said lower resilient contact element including an angularly disposedportion which exerts an outwardly and upwardly directed force against said door. I

40. In a dropout boxed fuse, the combination of a box having an open front, a lid for closing said open front, a separable hinge for connecting the lower end of the lid to the box whereby when the lldis otherwise released it tends to drop open by gravity, said hinge comprising a member fixedly mounted on the box, said hinge being provided with shoulders for stopping opening movement of the lid when it has traveled through approximately ninety degrees, said hinge members having means for preventing separation 'of the hinge members when said shoulders are in engagement, contact springs mounted in said box, an expulsion fuse having a tube carried on said lid, said tube being movable relative to the hinge, a fuse link in the tube holding the fuse tube and hinge against relative movement, a

lid and fuse tube without destruction of the fuse link.

'42. A fuse switch comprising a housing, line terminals therein, one element of a hinge therein, a removable fuse cartridge having terminal engaging elements adapted toassociate with said line terminals, a door for the housing carried by the cartridge and separate from the housing and adding its gravity effect to that of the cartridge, a second element on said hinge movably associated with said cartridge, a fuse link connecting with a terminal engaging element and holding the movable element on the cartridge substantially rigid with respect to the cartridge, and resilient means associated with the housing adapted to press theicartridge so as to tension said link when said terminal engaging elements engage said line terminals, said tensioned link preventing movement of the cartridge and door away from closed position but permitting such movement when the link is blown, the gravity effect of the door aiding that of the cartridge uponopening movement.-

43. A fuse switch comprising a housing, line terminals therein, one element of a hinge therein, a removable fuse cartridge having terminal engaging elements adapted to associate with said line terminals, 9. door for the housing carried by the cartridge and separate from the housing and adding its gravity effect to that of the cartridge, a second element on said hinge movably associated with said cartridge, a fuse link connecting with a terminal engaging element and holding the movable element on the cartridge substantially rigidwith respect to the cartridge, and resilient means associated with the housing adapted to press the cartridge so as to tension said link when said terminal engaging elements engage said line terminals, said tensionedlink preventing movement of the cartridge and door away from closed position but permitting such movement when the link is blown, the gravity effect of the door aiding that of the cartridge upon opening movement, and means permitting removal of said second element of the hinge from the hinge element on the housing, whereby the.

engagement with said line terminals when the fuse assembly is in closed position, and a fuse link extending through said cartridge and electrically connected between said conductive elements, one of said conductive members being movably mounted upon said cartridge andoperative upon the blowing of the fuse link to permit movement of said fuse assembly into open position.

45. In combination, a housing, a cover for said housing, a fuse on said cover, said fuse comprising a fuse tube open at one end and havingspaced terminals, locking means for said cover, means releasably holding said door closed,

- said means being normally restrained-against renals, a link in the tube connecting said terminals,

locking means for the cover, and spring means for producingrelative movement between the fuse tube and one of the fuse tube terminals to release said locking means upon parting of the link.

47. In combination, a housing, a cover for said housing, a fuse on said cover, hinge means for said cover, locking means for said cover, and

means operable upon blowing of the fuse for re ducing the distance between said hinge means and said locking means to release thelocking means for said cover.

48. In a device of the class described, a hous ing having a pair of contacts, a cover for said housing, a fuse on said cover for connecting said contacts in closed position of said cover, means for locking said cover closed and said fuse to one of said contacts, and spring means to release said locking means and simultaneously elongate the are upon blowing of the fuse.

49. In a device of the class described, a housing having a pair of contacts, a cover for said housing, a fuse on said cover for connecting said contacts in closed position-of said cover, means for locking said cover closed and said fuse to one of said contacts, spring means to release said locking means and simultaneously elongate the are upon blowing of the fuse, said fuse including a fuse link for restraining said spring means, and a lever for giving the fuse link mechanical advantage over said spring and operable upon blow-v ing of the fuse to multiply the speed of elongation of the arc.

50. In a cutout, a housing, a contact in said housing, a hinged cover for said housing, and a fuse on said cover and swingable into and out of engagement with said contact by the closing and opening movements of said cover, said contact having a spring action tensioned by the engagement of the fuse therewith and acting in the direction of opening movement of the cover to aid in swinging the cover to open position.

WILLIAM 0. SCHULTZ.

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