US2398469A

US2398469A - Fuse device

Info

Publication number: US2398469A
Application number: US435364A
Authority: US
Inventors: William O Schultz; Alwin G Steinmayer
Original assignee: Line Material Co
Current assignee: Line Material Co
Priority date: 1942-03-19
Filing date: 1942-03-19
Publication date: 1946-04-16
Anticipated expiration: 1963-04-16

Description

April 1946 w. o. SCHULTZ ETAL 2,398,469

' FUSE DEVICE Filed March 19, 1942 4 Sheets-Sheet 1 W 2 4 INVENTORS 10/11/441 0. \szwl/zrz AZlW/V a. sum/mm? I v A; TO/PNEY.

April 16, 1946.

w. o. SCHULTZ ErAL FUSE DEVICE Filed March 19, 1942 4 Sheets-Sheet 2 654..., A ZJW ATTORNEY.

April 16, 1946.

WrQSCHULTZ ELTAL FUSE DEVICE Filed March 19, 1942 4 Sheets-Sheet 4 p ATTORNEY.

Patented Apr. 16, 1946 UNITED STATES PATENT OFFICE FUSE DEVICE Application March 19, 1942, Serial No. 435,364

23 Claims.

This invention relates to a fuse device.

Objects of this invention are to provide a novel type of fuse device which is so made that it has an expulsion action at all times through its normally open end but which also is so made that the other end is normally closed but opens and provides for free venting of the generated gases upon ruptur of the fuse link in the event of a relatively large overload, the device therefore insuring an active expulsion action even for small overloads so as to insure the clearing of the fuse tube even under these light overload conditions and also providing for the relief of pressure, as stated, at both ends of the fuse tube for excessively heavy overloads to thereby increase the capacity of the device and insure its safety in operation.

Further objects are to provide a fuse construction having the above enumerated advantages which though it provides for venting of the fuse tube at both ends and provides intermediate means for engaging the head of the fuse link, is nevertheless so arranged that the intermediate means which engages the head of the fuse link has only a limited upward motion so that the resilient member from the corresponding stationary contact that engages the intermediate member will not be bent beyond a safe point, thereby avoiding damage to the upper stationary contact even in the event of a violent evolution of gas due to a large overload.

, Further objects are to provide a fuse device in which the intermediate member that engages the head of the fuse link is so arranged that it is held in its operative position by the resiliency of the cooperating stationary contact, and to so form and relate the parts that this intermediate member, even if it is not in its operative position when the fuse tube is being rocked to closed position, will be automatically moved to its correct operative position when the fuse tube is completely rocked into its service or closed position.

Further objects are to provide a fuse device in which guard means are provided for preventing water from running down the side of the fuse tube and also acting to keep the conducting gases vented from the upper end of the fuse tube from passing directly downwardly around the sides of the fuse tube.

Further objects are to provide a fuse device of simple construction having the above enumerated advantages in which an excellent electrical contact is secured between the head of the fuse link and the adjacent current carrying parts of the apparatus.

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

Figure 1 is a. view of one form of the invention, such view being partly in section.

Figure 2 is a sectional view on the line 2-2 of Figure 1.

Figure 3 is a view of the upper portion of a fuse device, showing a further form of the invention, such view being partly in section.

Figure 4 is a view looking down on the structure shown in Figure 3, with parts broken away and parts in section.

Figure 5 is a fragmentary view showing another form of the invention, such view being partly in section.

Figure 6 is a view looking down on the top of Figure 5.

Figure 7 is a view of the upper portion of a fuse device, showing a further form of the invention, such view being partly broken away.

Figure 8 is a view looking down on the structure shown in Figure 7.

Figure 9 is a view of the upper portion of a fuse device showing a further form of the invention, such view being partly broken away.

Figure 10 is a view looking down on the structure shown in Figure 9.

Referring to Figures 1 and 2, it will be seen that the fuse device includes the expulsion fuse tube I having a normally open lower end and provided with upper and lower portions cooperating with the upper and lower stationary terminals. The upper stationary terminal comprises the rigid arms 2 which project outwardly and are joined by a transverse web 3 from which a pair of flaring guide arms 4 project. The upper terminal also includes the spring contact member 5 which is provided with a downwardly curved catch portion 6 which in the normal position of the parts as shown in Figure l latches the fuse tube in operative or closed position. Th lower terminal comprises the rigid member I which terminatesin a pair of rearwardly and upwardly opening hook supports 8.

Suitable line and load conducting portions are provided and are indicated by the reference characters 9 and I0. These may be integral with the respective terminals or may be separate. They are shown separate for the upper terminal and integral for the lower terminal. These upper and lower terminals are attached to any suitable form of support. For example, the elongated insulator l I may be provided and bolts may extend through the insulator and thereby hold the terminals in place. The intermediate portion of the insulator is held by a suitable supporting mem ber l2.

The fuse tube I is provided at its lower end with a rearwardly projecting rigid arm l3 which has a sleeve l4 rigidly holding the fuse tube and locked thereto in any suitable manner, as by means of the pin I5. This rigid, rear-wardly projecting arm 13 terminates in bifurcated, downwardly extending ears it between which the fuse link extracting lever H is pivoted as indicated at H3. The fuse link extracting lever is provided with a thumb nut l9 carried by a threaded stem 20 and is adapted to grip the leader 2| of the fuse link. A suitable guiding lug 22 may be provided if desired.

This fuse link extracting lever is provided with a pair of laterally projecting trunnions 23 which removably fit within the hook supports 8 of the lower terminal. The rear portion of the fuse link extracting lever is preferably provided with an extended and rounded part 24 to prevent removal of the trunnions 23 from the hook supports 8 except when the fuse tube has rocked to its lower position. Preferably the portion 24 is extended upwardly and provided with a hook like part 25 adapted to receive a switch stick for replacing or removing the fuse from the lower terminal.

The construction at the lower end of the fuse tube is adapted, upon rupture of the fuse link, to rock the fuse tube downwardly and outwardly and allow it to detach itself from the upper stationary terminal and to rock downwardly to inoperative position. The fuse link extractor I! also serves to extract any remaining portion of the fuse link, in addition to the expulsion action which also acts to clear the fuse tube upon rupture of the fuse link.

The fuse link may take any of the usual forms and is provided with a fusible section 26 and with an upper button head 21. The upper end of the fuse tube is provided with an upper head member 28 which may be screwed or otherwise fastened thereto so that it is rigidly carried by the fuse tube. The head 28 is provided with a manipulating eyelet portion 29 which is adapted to receive a switch stick for rocking the fuse tube into operative position or for pulling the fuse tube out of operative position. The head is also provided with a rearwardly projecting arm 30 which is equipped with a laterally extending stop portion 3| for a purpose hereinafter to appear,

An intermediate member is provided which engages the button head 2! of the fuse link and also engages the spring contact arm of the upper stationary terminal. This intermediate member is in the form of a lever 32 which has downwardly extending ears 33 located on opposite sides of the rear end of the arm 30 and pivoted thereto by means of the pin 34. The ears 33 also act in the capacity of stops and engage the web 3 of the upper stationary terminal and thus limit inward rocking motion of the fuse tube. The lever is also provided with a projecting portion 35 on its upper side which latches behind the depressed portion 6 of the spring arm 5 of the upper stationary terminal.

It is to be noted that the point at which the pressure of the spring 5 is applied to the lever 32 is forwardly of the pivot pin 34 and consequently the spring 5 urges the lever downwardly towards fuse tube closed position.

The lever 32 also is provided with a downwardly hanging skirt portion 36 which extends around the sides of the upper end of the fuse tube, the head 28 forming a continuation of the fuse tube and having a bore therethrough of the same diameter as the fuse tube to thereby provide a fuse tube open at both ends with the upper end normally closed by the intermediate member or lever 32. It is to be noted that the skirt 36 is cut away adjacent the front so that it allows the free discharge of gases at the front away from the fuse tube to thereby lessen the chance of external flashovers. The fuse link extends through an opening in the lever 32 and its head is clamped in place by means of the clamping plug 31.

When an overload occurs and the fuse link is ruptured, an expulsion action takes place as the upper end of the fuse tube is closed temporarily by the intermediate lever 32 and this expulsion action assists in quickly clearing the fuse tube. In addition to this, the fuse link extractor IT rocks downwardly, withdrawing any remaining portion of the fuse link. If the overload is severe and the evolution of gases is considerable, the upper end of the fuse tube is vented as the lever or intermediate member 32 rocks upwardly and thus relieves gas pressure at the upper end as Well as at the permanently open lower end. Thus the device is enabled to handle large overloads without subjecting the fuse tube to excessive internal pressure. Even under heavy overloads, no damage is done the upper terminal for the outward rocking motion of the lever or intermediate member 32 is limited by engagement with the stop 3| so that the spring contact arm 5 is not stressed beyond a safe value.

When the fuse link is ruptured, the lower end of the fuse tube is moved downwardly and outwardly and the upper end detaches itself from latching engagement with the spring contact arm 5. The fuse tube then rocks downwardl to its lowermost position,

The fuse tube is removed from the lower terminal by engaging a switch stick with the hooked portion 25 and is re-fused and then replaced in the lower hooks 8. Thereafter the switch stick is caused to engage the eyelet portion 29 and the fuse tube is rocked back into operative position, the flaring arms 4 guiding the fuse tube into place.

It is obvious that the fuse tube may be rocked open without disturbing the fuse link by merely pulling outwardly on the eyelet portion 29.

The invention may take other forms some of which are shown in the succeeding figures.

In Figures 3 and 4 the fuse tube is indicated at 38 and is provided with a head portion 39 which has integrally formed therewith the manipulating eyelet portion 40 and a guard flange or barrier 4| which extends around the fuse tube and serves to prevent water from running down the outside of the fuse tube and also acts to divert or guard against the downward passage around the fuse tube of conducting gases discharged from the upper end of the fuse tube upon rupture of the fuse link.

It is to be distinctly understood that if desired the guard flange or disk ma be employed with the construction of Figure 1.

In the form of the invention shown in Figures 3 and 4 the button head 42 of the fuse link rests against the flat upper face of the head 39 of the fuse tube, such head being bored out so as to form a continuation of the bore of the fuse tube as described in connection with Figure 1, and the upper end being normall closed by the button head of the fuse link.

The head 39 of the fuse tube has a pair of spaced ears 43 between which a lever or intermediate member 44 is pivoted. This intermediate member is provided with an intermediate, downwardly projecting portion 45 which bears directly on the button head 42 of the fuse link. It is also provided with a rounded or cylindrical portion 46 extending transversely across the outer end of the lever or intermediate member 44.

The upper stationary terminal comprises the rigid arm 41 which is provided with a transverse web portion 48 and with a pair of flaring arms 49. The flaring arms 49 assist in guiding the fuse tube when the fuse tube is rocked to closed or operative position as previously described, and the web 48 coacts with a portion of the head 39 of the fuse tube to limit inward rocking motion of the fuse tube.

The flaring arms 49 are joined by a transverse portion 50 which extends over and is spaced from the spring contact arm 5| of the upper terminal. This spring contact arm 5| is secured as indicated at 52 adjacent its rear end to the rigid arm 41 of the upper terminal and at its outer end is provided with a depressed portion 53 which latches over the cylindrical portion 46 and thus latches the fuse tube in operative position. It is to be noted that the pressure of the spring acting on the outer end of the lever 44 produces a greater pressure on the head of the fuse link. The outer end of the spring arm is upwardly turned as indicated at 54 to provide a cam face beneath which the cylindrical portion 45 of the intermediate member or lever 44 may slide while the fuse tube is being rocked into closed or operative position.

The lower end of the fuse device shown in Figures 3 and 4 is made in the same manner as that shown in Figure 1.

Upon overload, the fuse tube moves downwardly and detaches itself from latching engagement with the upper terminal and rocks outwardly to its lowermost position. It is obvious that an expulsion action takes place under all conditions. It is particularly effective for small overloads as it assists in quickly clearing the fuse tube as previously described, The open upper end of the fuse tube is normall closed by means of the button head 42 of the fuse link and thus enhances the expulsion action. On heavy overloads the fuse device is arranged to vent the gases at the upper end as the button head is raised and the pressure gases quickly vented or discharged from the upper end of the fuse tube.

The overhanging member 50 prevents excessive motion upwardly of the spring contact arm 5| even under very heavy overloads and thus the spring contact arm 5| cannot be strained to a. detrimental degree.

It is to be noted from an inspection of Figures 3 and 4 that the lever 44 is provided with a rearwardly extending portion 44' which limits the amount of outward rocking motion of the lever or intermediate member 44 when the fuse tube is freed from the upper stationary terminal. This etxension 44', therefore, prevents the intermediate member or lever 44 from being inadvertently rocked clear over. This is necessary for if the lever or intermediate member 44 were rocked clear over, it would not be engaged by the spring contact arm 5| of the stationary upper terminal.

In the form of the invention shown in Figures 5 and 6 the fuse tube i indicated at 55 and is provided with a head 55. This head is bored out to provide a continuation of the bore of the fuse tube and carries the integrally formed eyelet portion 51. a fragment of which is shown in Figures 5 and 6. The head 56 is provided with an upwardly projecting lug 58 to which the spaced ears 59 of the intermediate member or lever, 50 are pivoted as-indicated at 6|. This intermediate lever is provided with a downwardly projecting portion 52 which bears against the button head 63 and is provided with a cylindrical portion 54 which latches with the contact spring arm of the upper stationary terminal, ashas been described in connection with Figure 3.

In the form of the invention shown in Figures 5' and 6 apair of 'leaf springs 55 have their free ends bearing against flat end portions of the ears 59 of the lever 60 and thus serve to releasably hold the lever 60 in the position shown in Figure 5. The lever, however, is free. to be rocked upwardly under the effects of ga pressure when the fuse link is ruptured as hereinbefore described. If desired, the head 56 may be provided with a projecting stop portion 66 which may engage the web 48 of Figure 3 and thus limit inward rocking motion of the fuse device.

When the device is being re-fused, the intermediate member or lever 60 may be rocked to a vertical position and the leaf spring 55 will engage the flat outer face of the lever 60 and will thus hold such lever in its vertical position, thus leaving the operator free to insert a new link.

It is obvious that even if the intermediate lever 60 of Figures 5 and 6 were left in a vertical position and the fuse tube were rocking to its closed position, such intermediate lever 60 would be rocked downwardly when it engaged the spring contact arm 5| of the upper stationary terminal, see Figure 3.

If desired the intermediate member or lever 60 of Figures 5 and 6 may be provided with a downwardly projecting flange or skirt 6! which extends around the sides of the upper end of the fuse tube. This skirt 61 is cut away at the front to provide for the free discharge of gases at the front to thereby lessen the chance of external flashovers.

The device of Figures 5 and 6 is designed to be used in connection with stationary contacts as has been described in connection with Figure 3. It is obvious that the upward motion of the lever 60 even under violent overload conditions is limited as the upward motion of the spring contact arm 5| of the upper stationary contact, see Figure 3, will be limited by the stop 50.

In the form of the invention shown in Figures 7 and'8 the fuse tube is indicated at 68 and is provided with a head portion 69. This head portion has a guard flange or disk 10 and an eyelet portion formed integrally therewith. It has an opening therethrough forming a continuation of the bore of the fuse tube as described in connection with Figure l. The head 69 is provided with a pair of upstanding lugs I2 between which a lever or intermediate member 13 is pivoted. This intermediate member or lever is provided with a pair of cylindrical projecting portions I4 and with a rearwardly projecting portion 15 which latter acts as a stop to limit the upward rocking motion of the intermediate member or lever 13 upon heavy overload. The intermediate member 13 bears downwardly against the button head I5 of the fuse link and holds the button head firmly in place, thus clos ing the open upper end of the fuse tube under normal conditions.

The upper stationary terminal may consist of a pair of spring contact arms which have a loop 18 and which are looped upwardly as indicated at 19 and which is clamped in place as indicated in Figure 7. If desired a pair of spacer member 80 may be clamped to the spaced spring contact arms 11. These members in conjunction with the ears [2 of the fuse tube form a stop to limit inward rocking motion of the fuse tube. The spring arms 11 are provided with downwardly depressed portion Bl Which hook over the members 14 and thus latch the fuse tube in operative position. The outer end of the spring arms ll extend upwardly and outwardly as shOWn in Figures 7 and 8, the outwardly flaring portions serving as guides to assist in guiding the fuse tube into correct position when it is rocked to closed position and the cam like slanting lower surfaces riding over the cylindrical portions 14 when the fuse tube is rocked to closed position.

In the form of the invention shown in Figures 9 and 10 the fuse tube is indicated by the reference character 82. It is provided with a head portion 83 which has an integrally formed guard ring or disk 84 and an eyelet portion 85. Thi head portion is bored out so as to have the same bore as that of the fuse tube, as has been described in connection with Figure 1. It is provided with a pair of rearwardly extending lugs 86 between which the intermediat member or lever 81 is pivoted. Thi intermediate member or lever 81 is provided with a downwardly extending portion 88 which bears against the button head 89 of the fuse link and is provided with a forwardly and upwardly extending portion 9!).

The upper stationary terminal comprises a pair of side plates or bars 9| which may be of rel atively rigid material and which extend outwardly and terminate in outwardly flared ends 92, see Figure 10, which assist in guiding the ise tube into position when it is rocked inwardly. The upper stationary terminal also includes the resilient contact arm 93 which is provided with a downwardly extending protuberance 94 which bears against the lever 81 and urges the portion 88 of this lever or intermediate member 81 into engagement with the button head of the fuse link.

The lower portion of the structure of the form of the invention shown in Figure 9 may be like that shown in Figure 1.

In Figures 9 and 10 when the fuse blows, an expulsion action takes place under all conditions. With very light overloads sufficient to rupture the fuse link this expulsion action is Very desirable for quickly clearing the fuse tube, in addition to the fuse link extracting action hereinbefore described. However, when the overloads are severe and a quantity of gas is evolved upon rupture of the fuse link, the fuse tube vents the gases at the upper end of the fuse tube as well as at the lower end as it raises the button head against the action of the intermediate lever and spring arm 93. The rocking motion of the intermediate lever or member 81 also assists in throwing the fuse tube outwardly away from the upper stationary contact, as is obvious from an inspection of Figure 9. The upward rocking motion of the intermediate member or lever 81 is limited as such lever is provided with a rearwardly extending portion 95 which acts as a stop and determines the extent of the outward rocking motion of the intermediate member or lever.

In all forms of the invention it will be seen that a fuse tube has been provided which is open at both ends and which always acts to expel the fuse link with afull expulsion action. This expulsion action takes place for large and small overloads. In addition to this action there is the fuse link extracting action for withdrawing any remaining portion of .the fuse link as the lower portion of all forms of the device are made as described in connection with the form shown in Figure 1. There is also the extra venting of the gases at the upper end of the fuse tube as has been described in detail for the several forms of the invention. This gives an immediate relief of pressure not only at the permanently open lower end of the fuse tubes but also at their upper ends as well, thereby enabling the fuse devices to handle much larger overloads with safety to the fuse tube itself.

It is to be noted that in the forms of the invention shown in Figures 3 to 10 the button head of the fuse tube may be blown from the device under heavy overloads and it will be seen that in all forms of the invention means are provided for engaging the button head of the fuse link and that such means is urged towards a position where the upper end of the fuse tube is closed by means of the resilient downward pressure of the spring arm or spring arms of the upper stationary terminal. All forms of the invention are designed for drop-out action as described in detail in connection with Figure 1 so that after the fuse has blown, the fuse tube is removed from circuit and is supported solely from the lower stationary terminal having dropped downwardly to inoperative position after being unlatched from the upper stationary terminal.

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

We claim:

1. A fuse device comprising a pair of stationary terminals, a fuse tube open at both ends, a fuse link extending through said fuse tube and normally electrically connecting said stationary terminals, means including a movable intermediate member for yieldingly closing one end of said fuse tube, said intermediate member forming an electrical connection between the fuse link and one of said stationary terminals and movable outwardly from said fuse tube under the action of gas pressure upon rupture of the fuse link, and means limiting the outward motion of said intermediate member, whereby said one stationary terminal will not be injured by outward motion of said intermediate member upon violent overloads.

2. A fuse device comprising a pair of stationary terminals, a fuse tube open at both ends, a fuse link extending through said fuse tube and normally electrically connecting said stationary terminals, means including a movable intermediate member for yieldingly closing one end of said fuse tube, said intermed ate member directly engaging one end of the fuse link and connecting such end of the {use link to the corresponding stationary terminal, said intermediate member being movable outwardly from said fuse tube under the action of gas pressure upon rupture of the fuse link, and means limiting the outward motion of said intermediate member, whereby the corresponding stationary terminal will not be injured by outward motion of said intermediate member upon violent overloads.

3. A fuse device comprising a pair of stationary terminals, a fuse tube open at both ends, a fuse link extending through said fuse tube and. normally electrically connecting said stationary terminals, a movable intermediate member carried bysaid fuse tube adjacent one end thereof and normally closing such end of said fuse tube and biased towards closed position, said intermediate member having means clamping the end ofv said fuse link and forming an electrical connection between the corresponding stationary terminal and the said end of said fuse link, said movable intermediate member being movable outwardly from said fuse tube under the action of gas pressure upon rupture of the fuse link, and means for limiting the outward motion of said intermediate member whereby the corresponding stationary terminal will not be injured by outward motion of said intermediate member upon violent overloads.

4. A fuse device comprising a pair of stationary terminals, one of said stationary terminals having a yieldingly urged portion, a fuse tube open at both ends, a fuse link extending through said fuse tube and normally electrically connecting said stationary terminals, means including a movable intermediate member for normally closing one end of said fuse tube, said intermediate member being normally held in closed position by said yieldingly urged portion of said one stationary terminal and being movable outwardly from the fuse tube under the action of gas pressure upon rupture of the fuse link, said intermediate member directly engaging the end of said fuselink, and means limiting the outward motion of said intermediate member whereby said yieldingly urged portion of the stationary terminal will not be injured by outward motion of said intermediate member upon violent overloads.

5. A fuse device comprising a pair of stationary terminals, one of said stationary terminals having a yieldingly urged portion, a fuse tube open at both ends, a fuse link extending through said fuse tube and normally electrically connecting said stationary terminals, said fuse link having a headed portion normally closing one end of said fuse tube, an intermediate member interposed between said head of said fuse link and said yieldingly urged portion of said stationary terminal and transmitting the force of said yieldingly urged portion to the head of said fuse link, the head of said fuse link being movable outwardly from said fuse tube under the action of gas pressure upon rupture of said fuse link, and means limiting the outward motion of said intermediate member whereby said yieldingly urged portion of said stationary terminal will not be injured by outward motion of said intermediate member upon violent overloads.

6. In a fuse device, a pair of stationary terminals, one of said terminals having a yieldingly urged portion, a fuse tube open at both ends, a fuse link extending through said fuse tube and normally electrically connecting said terminals, intermediate movable means including a head on the fuse link and a movable member, said intermediate means being biased to normally close one end of said fuse tube and forming an electrical intermediate connection between said fuse link and the yieldingly urged portion of said stationary terminal, and means carried by said fuse tube for limiting the outward motion of said movable member.

7. In a fuse device, a pair of stationary terminals, one of said terminals having a rigid guiding portion and having a yieldingly urged portion,

a fuse tube open at both ends, a fuse link extend ingthrou ghsaid fuse tube and normally electrical'ly' connecting said terminals, and an intermediate movable leverhaving means for engaging the-end of said fuse link, said lever normally closing; one; end 'of said fuse tube and forming an electrical intermediate connection between said fuse link and the yieldingly urged portion of said stationary terminal, said lever being movable outwardly under the action of gas pressure upon rupture of said fuse link.

8.- Ina fuse device, a pair of stationary terminals, one of said terminals having a yieldingly urgedportion, a fuse tube open at both ends, a fuse link extendingthrough said fuse tube and normally electrically connecting said terminals, an intermediate movable lever having means for engaging the end of; said fuse link, said lever normally closing one end of said fuse tube and forming an electrical intermediate connection between said fuse link and the yieldingly urged portion of said stationary terminal, said lever being movable outwardly under the action of gas pressure upon rupture of said fuse link, and means for limiting the outward motion of said lever, whereby the yieldingly urged portion of said stationary terminal will not be damaged under violent overloads. I

9. In a fuse device, a pair of stationary terminals, one of said terminals having a yieldingly urged portion, a fuse tube open at both ends, a fuse link extending through said fuse tube and normally electrically connecting said terminals, said fuse link having ahead normally closing one end of said fuse tube, and an intermediate lever between said head and the yieldingly urged portion of said stationary terminal, said intermediate lever transmitting and multiplying the force of said yieldingly urged portion to said head to maintainsaid head in tube-closed position under normal conditions.

10. In a fuse device, a pair of stationary terminals, one of said terminals having a, yieldingly urged portion, a fuse tube open at both ends, a fuse linkextending through said fuse tube and normallyelectrically connecting said terminals, said fuse link having a head normally closing one end of said fusev tube, an intermediate lever between said head and the yieldingly urged portion of said stationary terminal, said intermediate lever transmitting the force of said yieldingly urged portion to said head'to maintain said head in tube-closed position under normal conditions, and means for limiting the outward motion of said lever upon violent overloadswhereby damage to theyieldingly ,urged'portion of said stationary terminal is avoided.

11. In a drop-out fuse device, an upper and a lower stationary terminal, said upper stationary terminal; having a rigid guiding'portion and having a yieldingly urgedportion, a fuse tube open at both ends and movably supported adjacent its lower endafor drop-out motion, a fuse link extending through said fuse tube and normally electrically, connecting said terminals, means adjacent the lower end of said fuse tube controlled by said fuse link for releasing said fuse tube for drop-out motion upon rupture of said fuse link, and intermediate movable means including a head on, saidfuse link and a movable member, said intermediate means normally closing the upper end of said fuse tube and forming' an electrical intermediate connection between said fuse link and the yieldingly urged portion of said upper stationary terminal.

2 12-. In a drop-out fuse device, an upper and a lower stationary terminal, said upper stationary terminal having a rigid guiding portion and having a yieldingly urged portion, a fuse tube open at both ends and movably supported adjacent its lower end for drop-out motion, a fuse link extending through said fuse tube and normally electrically connecting said terminals, means adjacent the lower end of said fuse tube controlled by said fuse link for releasing said fuse tube for drop-out motion upon rupture of said fuse link, and intermediate movable means including a head on said fuse link and a movable member, said intermediate means normally closing the upper end of said fuse tube and forming an electrical intermediate connection between said fuse link and the yieldingly urged portion of said upper stationary terminal, said intermediate means being urged towards tube-closed position by the force exerted by the yieldingly urged portion of said upper stationary terminal.

13. In a drop-out fuse device, an upper and a lower stationary terminal, said upper stationary terminal having a rigid guiding portion and having a yieldingly urged portion, a fuse tube open at both ends and movably supported adjacent its lower end for drop-out motion, a fuse link extending through said fuse tube and normally electrically connecting said terminals, means adjacent the lower end of said fuse tube controlled by said fuse link for re1easing said fuse tube for drop-out motion upon rupture of said fuse link, and an intermediate movable means including a head on the fuse link and a pivoted lever, said intermediate means normally closing the upper end of said fuse tube and forming an electrical intermediate connection between said fuse link and the yieldingly urged portion of said upper stationary terminal, said lever and said yieldingly urged portion having detachable interlockin means forming a latch for the upper end of said fuse tube.

14. In a drop-out fuse device, an upper and a lower stationary terminal, said upper stationary terminal having a rigid guiding portion and having a yieldingly urged portion, a fuse tube open at both ends and movably supported adjacent its lower end for drop-out motion, a fuse link extending through said fuse tube and normally electrically connecting said terminals, means controlled by said fuse link for releasing said fuse tube for drop-out motion upon rupture of said fuse link, and an intermediate movable lever carried by said fuse tube and having means for engaging the end of said fuse link, said lever normally closing one end of said fuse tube and forming an electrical intermediate connection between said fuse link and the yieldingly urged portion of said upper stationary terminal, said lever bein movable outwardly under the action of gas pressure upon rupture of said fuse link.

15. In a drop-out fuse device, an upper and a lower stationary terminal, said upper stationary terminal having a yieldingly urged portion, a fuse tube open at both ends and movably supported adjacent its lower end for drop-out motion, a fuse link extending through said fuse tube and normally electrically connecting said terminals, means controlled by said fuse link for releasing said fuse tube for drop-out motion upon rupture of said fuse link, an intermediate movable lever carried by said fuse tube and having mean for engaging the end of said fuse link, said lever normally closing one end of said fuse tube and forming an electrical intermediate connection between said fuse link and the yieldingly urged portion of said upper stationary terminal, said lever-being movable outwardly under the action of gas pressure upon rupture of said fuse link, and means for limiting the outward motion of said lever, whereby the yieldingly urged portion of said stationary terminal will not be damaged under violent overloads.

16. In a drop-out fuse device, an upper and a lower stationary terminal, said upper stationary terminal havin a rigid guidin portion and having a yieldingly urged portion, a fuse tube open at both ends and movably supported adjacent its lower end for drop-out motion, a fuse link extending through said fuse tube and normally electrically connecting said terminals, means adjacent the lower end of said fuse tube controlled by said fuse link for releasing said fuse tube for drop-out motion upon rupture of said fuse link, and an intermediate movable lever carried by said fuse tube and having means for engaging the end of said fuse link, said lever normally closing the upper end of said fuse tube and forming an electrical intermediate connection between said fuse link and the yieldingly urged portion of said upper stationary terminal, said lever and said ieldingly urged portion of said upper stationary terminal having detachable interlocking means constituting latch means for the upper end of said fuse tube.

17. In a drop-out fuse device, an upper and a lower stationary terminal, said upper stationary terminal having a rigid guiding portion and having a yieldingly urged portion, a fuse tube open at both ends and movably supported adjacent its lower end, a fuse link extending thr ugh said fuse tube and normally electrically connecting said terminals, said fuse link having a head normally closing the upper end of said fuse tube, means adjacent the lower end of said fuse tube controlled by said fuse link for releasing said fuse tube for drop-out motion upon rupture of said fuse link, and an intermediate lever between said head and the yieldingly urged portion of said upper stationary terminal, said intermediate lever transmitting the force of said yieldingly urged portion to said head to maintain said head in tube-closed position under normal conditions, said intermediate lever and said yieldingl urged portion having detachable interlocking means for releasably latching the upper end of said fuse tube.

18. In a drop-out fuse device, an upper and a lower stationary terminal, said upper stationary terminal having a yieldingly urged portion, a fuse tube open at both ends and movably supported adjacent its lower end, a fuse link extending through said fuse tube and normally electrically connecting said terminals, said fuse link having a head normally closing the upper end of said fuse tube, means adjacent the lower end of said fuse tube controlled by said fuse link for releasing said fuse tube for drop-out motion upon rupture of said fuse link, an intermediate lever between said head and the yieldingly urged portion of said upper stationary terminal, said intermediate lever transmitting the force of said yieldingly urged portion to said head to maintain said head in tube-closed position under normal conditions, said intermediate lever and said yieldingly urged portion having detachable interlockin means for releasably latching the upper end of said fuse tube, and means for limiting the outward motion of said lever upon violent overloads, whereby damage to the yieldingly urged portion of said upper stationary terminal is avoided.

19. In a drop-out fuse device, an upper and a lower stationary terminal, said upper stationary terminal having a rigid guiding portion and having a yieldingly urged portion, a fuse tube open at both ends and movably supported adjacent its lower end for drop-out motion, a guard disk carried by said fuse tube below the upper end thereof and projecting laterally outwardly from said fuse tube and located below said upper stationary terminal, said guard disk being located between said terminals when said fuse tube is in operative position, a fuse link extending through said fuse tube and normally electrically connecting said terminals, means controlled by said fuse link for releasing said fuse tube for drop-out motion upon rupture of said fuse link, and intermediate movable means including a head on said fuse link and a movable member, said intermediate means normally closing one end of said fuse tube and forming an electrical intermediate connection between said fuse link and the yieldingly urged portion of said upper stationary terminal.

20. A fuse device comprising a pair of stationary terminals, a fuse tube open at both ends, a fuse link extending through said fuse tube and normally electrically connecting said stationary terminals, means including a movable intermediate member for yieldingly closing one end of said fuse tube, said intermediate member forming an electrical connection between the fuse link and one of said stationary terminals and movable outwardly from said fuse tube under the action of gas pressure upon rupture of the fuse link, a guard disk carried by said fuse tube adjacent to the said one end of said fuse tube and projecting laterally outwardly from said fuse tube, said guard disk being located between said terminals when said fuse tube is in operative position, and means limiting the outward motion of said intermediate member, whereby said one stationary terminal will not be injured by outward motion of said intermediate member upon violent overloads.

21. A fuse device comprising a pair of stationary terminals, a fuse tube open at both ends, a fuse link extending through said fuse tube and normally electrically connecting said stationary terminals, means including a movable intermediate member for yieldingly closing one end of said fuse tube, said intermediate member directly engaging one end of the fuse link and connecting such end ofthe fuse link to the corresponding stationary terminal, said intermediate member being movable outwardly from said fuse tube under the action of gas pressure upon rupture of the fuse link, a guard disk carried by said fuse tube adjacent to the said onev end of said fuse tube and projecting laterally outwardly from said fuse tube, said guard disk being located between said terminals when said fuse tube is in operative position, and means limiting the outward motion of said intermediate member, whereby the corresponding stationary terminal will not be injured by outward motion of said intermediate member upon violent overloads.

22. A fuse device comprising an upper and a lower stationary terminal, a fuse tube open at both ends, a fuse link extending through said fuse tube and normally electrically connecting said stationary terminals, and means including an intermediate member directly engaging one end of said fuse link for yieldingly closing the upper end of said fuse tube and for connecting said fuse link with said upper stationary terminal, said movable intermediate member having a skirt extending downwardly around the side portions of the upper end of said fuse tube, said intermediate member being movable outwardly from said fuse tube under the action of gas pressure upon rupture of the fuse link and the skirt being cut away adjacent the front of said intermediate member for the unobstructed discharge of gases outwardly away from the fuse tube.

23. A fuse device comprising an upper and a lower stationary terminal, a fuse tube open at ,both ends, a fuse link extending through said fuse tube and normally electrically connecting said stationary terminals, means including an intermediate member directly engaging one end of said fuse link for yieldingly closing the upper end of said fuse tube and for connecting said fuse link with said upper stationary terminal, said movable intermediate member having a skirt extending downwardly around the side portions of the upper end of said fuse tube, said intermediate member being movable outwardly from said fuse tube under the action of gas pressure upon rupture of the fuse link and the skirt being cut away adjacent the front of said intermediate member for the unobstructed discharge of gases outwardly away from the fuse tube, and means limiting the outward motion of said intermediate member whereby said upper stationary terminal will not be injured by the outward motion of said intermediate member upon violent overloads.

WILLIAM O. SCHULTZ. ALWIN G. STEINMAYER.