US2378109A - Fuse construction - Google Patents

Description

June 12, 1945. Q S HUL Z 2,378,109

FUSE CONSTRUCTION Filed Nov. 14, 1942 3 Sheets-Sheet l jg 141/ 56 I INVENTOR.

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1/4/24 0. Jam/z rz Jun 12, 1945.

w. o. scHpurz 2,378,109

FUSE CONSTRUCTION Filed Nov. 14, 1942 3 Sheets-Sheet 5 IN VEN TOR.

47m NEY.

Mil/4M 0. Jam rz Patented June 12, 1945 UNITED STATES' PATENT OFFICE FUSE CONSTRUCTION William 0. Schultz, South Milwaukee, Wis., assignor to Line Material Company, South Mllwaukee, Wis., a corporation of Delaware Application November 14, 1942-, Serial No. 465,566

Claims.

This invention relates to fuse constructions and is particularly directed to drop-out fuse constructlons.

Objects of this invention are to provide a fuse construction in which the fuse tube may be made as long or as heavy as desired, but in which the arrangement of the parts is so made that the fuse link is not unduly strained by the weight of the fuse tube and its associated parts but in which fuse links either of a heavy or a light capacity may be employed without; danger of unduly straining the fuse link.

Further objects are to provide a novel form of drop-out fuse device in which heavy contact pressure is obtained for both the upper and the lower contacts of the fuse tube without unduly straining the fuse link, in which arugged, simple type of contact means is provided which is highly resilient and eliminates the necessityof any flexible copper connections, braids, or other means of transmitting current from one member to the other, and in which the contact means is-so'an excellent electrical contact between the end of the fuse link and the lower contact structure of the fuse tube and to so organize this spring pressed gripping means and the flip-out or fuse link extracting lever that the fuse link extracting lever will strike a blow on the gripping means and will thereafter interlock with the gripping are urged apart in opposite directions by the same spring means, and to provide interengaging or interlocking portions between the fuse link extracting lever and the gripping member so that these parts lock together and rock as a unit after the fuse link has been partially extracted, thereranged that it provides a downward and outward force for urging the fuse tube downwardly and outwardly towards rockin motion to open position, the fuse tube being normally retained in' circuit closed position and being released for dropout motion upon rupture of the fuse link. Further objects are to provide a novel construction for receiving the blow due to arresting the downward and outward rocking motion 'of the fuse tube when it has arrived at its lower limit of travel, such means providing for substantially direct transmissionof the force of the blow to a stationary portion of the lower contact structure and transmitting the force of the blow substantially directly transversely across a lower main lever which normally supports the fuse tube in its operative or circuit closed position Further object are to provide a drop-out; fuse construction in which fuse link extracting arid flip-out means are provided for quickly extracting any unburned portion of the fuse linkupon by insuring positive release of the fuse link and also insuring the complete throwing out of the fuselink free and clear of the fuse tube.

pressed gripping means for gripping th endof Further objects are to provide a manually operable latch for temporarily locking the fuse link gripping means in 'open position so that the fuse link may be freely passed betweenthe gripping means and the associated parts of the apparatus, the manual latching means being rockable to released position tothereby release the gripping means and allow it to firmly grip the end of the fuse link, the arrangement of the temporary latch being such that after it is manually released, gravity will tend to hold the temporary latching means'in its unlatched position.

Further objects are to provide a drop-out fuse construction which is so arranged that it will normally vent or discharge from its lower end, but in which. clamping means are provided for .the head, such as the buttonhead of the fuse link at the upper end of the fuse tube, the head ofthe fu'se, link normally closing the u per end of the fuse tube so that the device will have a 'downward expulsion action through its open lower end, the arrangement, being such, however, that upon high overload the fuse tube will vent at both ends, thereby increasing the capacity of the apparatus without unduly straining the fuse tube. Further objects are to provide a drop-out fuse device in which the fuse tube is supported from the lower contact by means of a double hinge construction, and to provide a contact spring for insuring positive contact between the lower stationary contact and the lower contact structure of the fuse tube, such contact means also urging the fuse tube towards outward rocking motion, and to provide a hood like construction for shielding both the doubl hinge construction and the lower contact spring, thereby protecting such structure from the accumulation of ice and snow.

Further objects are to provide a drop-out fuse construction in which the fuse tube after it has dropped to open position upon rupture of the fuse link, may be freely removed from the stationary portion of the apparatus by means of a switch stick and may be refused and thereafter replaced by means of the switch stick in a simple and easy manner, the switch stick being then used to rock the fuse tube into circuit closing position.

Further objects are to provide a drop-out fuse construction which is rugged, which is free from fragile and delicate parts, which has a relatively small number of parts, and which is highly reliable in operation.

An embodiment of the invention is shown in the accompanying drawings, in which:

Figure l is a side elevation of the device with the fuse tube shown in circuit closed position, parts of the apparatus being shown in section.

Figure 2 is an enlarged view of the fuse tube and its associated parts removed from the stationary portion of the apparatus, such view being partly in section and partly broken away.

Figure 3 is a sectional view on the line 3-3 of Figure 2.

Figure 4 is a bottom view of the structure shown in Figure 2.

Figure 5 is a fragmentary sectional viewon the line 5-5 of Figure 1.

Figure 6 is a fragmentary sectional view on the line 6-6 of Figure 1.

Figure 7 is a fragmentary view of the lower portion of the apparatus after the fuse tube has rocked downwardly to its lowermost position.

Referring to the drawings, it will be seen that the device comprises a fuse tube I which has an upper contact structure indicated generally by the reference character 2 and a lowercontact structure indicated generally by the reference character 3. The fuse tube, as may be seen from Figure 2, is open at both ends. Its upper end is normally closed by the head such as the buttonhead 4 of the fuse link, such fuse link being preferably provided with a reduced fusible section 5 adjacent the upper portion of the fuse tube and a flexible leader 6 extending outwardly through the lower open end of the fuse tube. I

The upper contact structure indicated generally by the reference character 2 comprises a sleeve like portion 1 which is threaded or otherwise secured to the upper end of the fuse tube and which has a bore opening through its upper end forming an extension of the bore of the fuse tube. The upper contact structure preferably includes a tubular upwardly extending neck portion 8 which has a flat upper surface on which the head 4 of the fuse link rests, the head of the fuse link being of a larger diameter than the cylindrical portion 8.

A pair of fuse link gripping arms 9 and [0 are hingedly mounted as indicated at H to the upper contact 2 of the fuse tube and are provided with curved, diametrically opposed portions which enage diametrically opposite points of the marginal edge of the head 4 of the fuse link. The clamping arms 9 and i 0 are held in clamping position by means of a U-shaped member 12 which is pivoted as indicated at ii to the arm l0 and into which the screw [4 is threaded. The screw I4 is provided with a knurled head as indicated and with a rounded inner end which seats within a socket like portion of the arm 9 so that when the screw I 4 is tightened, the arms 8. and i0 securely and firmly grip the head 4 of the fuse link and thus afford a very good electricalcontact between the upper end of the fuse link and the upper contact 2 of the fuse tube.

The upper contact 2 of the fuse tube is p e erably provided with a manipulating eyelet portion I! which may be engaged by a switch stick to manually open or manually close the fuse tube by rocking it about its lower support, as will appear as the description proceeds.

It is to be noted particularly with reference to Figures 1, 5 and 6, that the upper contact 2 of the fuse tube is provided with a pair of outwardly extending contact arms I6 projecting outwardly in opposite directions. These arms when the fuse tube is in circuit closed position are engaged in a firm and secure manner by the downwardly urged spring arms I! of the upper stationary contact structure. These spring arms may have divergent outer portions I8, as shown most clearly in Figure 5, to assist in guiding the upper end of the fuse tube in place. The spring arms I l are formed by means of a continuous, approximately U-shaped, heavy, resilient contact which is provided with a central rear portion 19 and with a pair of looped portions 20 to increase its resiliency.

It is to be noted that the inner or looped portion I9 of the spring contact arms is loosely pivotally held to the stationary bracket 2i of the upper stationary contact structure. This bracket is provided with a lower tongue 22 which is bent backwardly beneath the portion I8 of the spring arms to loosely pivotally retain the spring arms in place.

The bracket 2| extends forwardly and is provided with a transverse wall 23 at its outer end which acts as a stop for the inwardly projecting tip 24 of the upper contact 2 of the fuse tube to limit the inward rocking motion of the fuse tube. It is to be noted from reference to Figure 1 that the spring arms H are provided with a downwardly bent latching portion 25 which latche in front of the pins I6 of the upper contact structure 2 of the fuse tube to thus yieldingiy and securely latch the fuse tube in circuit closed position.

It is to be noted that the wall or web 23 of the bracket 2|, as shown in Figure 6, is provided with upwardly diverging cam faces 26 against which the sp ing contact arms I! bear. The spring contact arms ll tend to move inwardly towards each other and when they are deflected upwardly by means of the pins or contact portions l6 of the upper contact structure of the fuse tube when the fuse tube is rocked into circuit closed position, the spring arms are spread apart by the cam faces 26 and thus secure a very firm and excellent electrical contact not only with the pins l6 but with the bracket 2| as well. It is to be noted that the bracket 2| is integral with an upper connector receiving terminal 21 and that such bracket is bolted to the insulator 28 carried is open at its bottom portion and is provided with side and .top ortions. The lower stationary contact structure also includes a pair of upwardly elongated hook like portions 34 which detachably receive the trunnions 35 of a main lever 36.

This lower contact structure is bolted to the lower insulator 31 which is carried in any suitable manner by-the stationary supporting portion 29.

The fuse tube carries a rigid, rearwardly and. downwardly extending arm 38 which may include a split sleeve portion 39 which is held clamped or locked to the lower portion of the fuse tube by means of a bolt 40, such bolt also fitting in a transverse groove formed in the fuse tubeto prevent inadvertent turning of the fuse tube with reference to the clamping sleeve 39 of the arm 38.

The arm 38 is in reality two spaced arms.

The supporting arm structure 38 composed of the two arm portions is pivoted as indicated at 4! to the main lever 36, the main lever it being rer'nembered being provided with the trunnions 35 r so that a double hinge support is provided for the fuse tube.

It is to be noted from reference .to Figure 1. that the pivot 4i and the trunnions 35 are arranged substantially directly above each other.

. As a matter of fact, the pivot 41 is spaced slightly outwardly with reference to the trunnions 35. However, the contactspring 32 firmly bears against a projectingear 42 integral with the main lever 36 and thus urges the fuse tube towards outward rocking motion. It therefore 'is possible, if desired, and within the contemplation of this invention, to have the pivot 4| directly above the trunnions 35.

The main lever 36 pivotally carries a fuse link extracting and flip-out lever 43 which is provided with a rounded outer portion 44 about which the outer end of the leader of the fuse link extends and with a channeled lower portion indicated at 45 in Figure 2 within which the leader of the fuse link is positioned. This fuse link extracting and flip-out lever 43 is curved upwardly at its inner end and is normally located in close proximity to the lower open: end of the fuse tube. as shown most clearly in Figure 2. It is pivoted to the main lever by means of the pivot 46 and is spring urged downwardly towards fuse link ex tracting motion by means of the spring 41, one end of which bears directly against the fuse link extracting and flip-out lever 43.

The fuse link extracting and flip-out lever is provided with a manipulating, laterally projecting thumb piece 48, as shown in Figure 4, to facilitate refusing of the device as will appear herein after. V V

A fuse link clamping member or lever indicated generally'by the reference character 43 is also carried by the pivot 46. It is provided with a shouldered fuse link gripping portion 50 which grips the leader or end of the fuse link between itself and an overhanging portion 51 of the main lever 33. Preferably an outwardly and upwardly curved shield portion 52 is formed on the main lever, as shown in Figure 2.

Itis to be noted that the spring 41 has its other end bearing against thefuse link clamping lever or member 49 so that the fuse link clamping lever 49 and the fuse link extracting and flip-out lever 43 are urged in opposite directions. I

. It is to be noted further that the fuse link extracting and flip-out lever 43 is provided with shouldered ear portions 53 which are adapted to has rocked outwardly a predetermined distance. Whenthe cars 53 of the fuse link extracting lever engage the portion 54 of the fuse link clamping lever 48, these two levers are then interlocked and the force of the spring 41 does not thereafter retain the fuse link clamping lever 49 in clamping position.

Instead these two members move as a unit and release the fuse link so that the fuse link may be thrown substantially directly downwardly from the fuse tube, the momentum acquired by the part 43 under the influence of the spring 47 and gravity being sufficient to carry along the part 49 after the parts 43 and 49 have been locked together.

The main lever 36 is bifurcated and straddles the lower portion of the fuse tube. It is provided with a pair of feet 55 which when the fuse tube has rocked to its lowermost position, as shown in Figure 7, engage the stationary lower contact 33. The fuse tube transmits the force of the blow due to its fall to the sleeve like portion 39 which is provided with a pair of bearing feet 56 which engage the main lever 36 at a point substantially directly in line with the feet 55, as shown in Fi ure 7, so that the force of the blow is transmitted from the lower part of the fuse tube substantially directly across the main lever 36 to the lower stationary contact 30 and thus the tendencyto bend the main lever 35 is avoided.

The sleeve like portion 39 is provided with a pair of outwardly projecting arms 5'l which are joined by a web portion 58 to therebyfprovide an eyelet like portion, and such sleeve 39 is also provided with a pair of spaced arms 59 so that a switch stick may be inserted between th arms 59 and its knob or head like portion may be engaged behind the web 53 so that the fuse tube may be lifted into or out of the position shown in Figure '7 by means of the switch stick.

After the device has operated in response to overload, it occupies the position shown in Figure 7. It may be lifted from such position by means ofthe switch stick, may be refused and repositioned by means of the switch stick." Thereafter the switch stick is caused to engage the eyelet portion l5, see Figure l, and the fuse tube is rocked back into circuit closed position.

The operation-of the apparatus on overload is as followsz when overload occurs, the fuse link is ruptured {and the auxiliary or fuse link extracting andlflip-out lever 43 tends to move downwardly under the influence of the spring "to quickly flip-out or withdraw any'remaining unburned portion of the fuse link substant ally directly downwardly in line with the fuse tube. In 7 downwardly and carries the pivot point 46 of the fuse link extracting and flip-out lever downwardly. Thus this motion of the m'ain lever combined with that of the fuse link extracting and flip-out lever produces a very long relative travel between the inner free end of the fuse link ex-' tracting and flip-out lever 43 and the lower end of the fuse tube.

It is to be noted particularly that the fuse link extracting and flip-out lever 43 executes a very quick stroke and quickly extracts any unburned portion of the fuse link. Also while the fuse'link ber 60.

extracting and flip-out lever is completing its stroke and while any remaining portion of the fuse link is still in downward motion, the clamping lever or clamping member 48 is moved in a positive manner to open position and releases the fuse link so that the fuse link is thrown or dropped downwardly clear and free of the apparatus.

It is to be noted particularly that during the final outward stroke of the fuse link extracting and flip-out lever 43, the shouldered portion 53 thereof engages the portion 54 of the latchin member 49 and the spring 41 thereafter has no further effect. The two members 43 and 49 then move as a unit and release the fuse link in a positive and certain manner, the momentum acquired by the part 43 under the influence of the sprin t; and gravity being sufllcient to carry along the part 49 after the parts 43 and 43 have been locked together.

Under heavy overloads the fuse tube can vent itself at both ends as the buttonhead 4, see Fi ure 2, is blown directly upwardly and passes outwardly between the clamping jaws or members 9 and id. Preferably the faces of these clamping members are made slightly upwardly flaring to facilitate the free discharge of the head 4 when high gas pressure is generated within the fuse tube. Under lighter overloads, the head 4 remains in place and the fuse tube acts as a straight expulsion fuse tube discharging the gases from the lower end thereof.

After the fuse tube has dropped to the position shown in Figure 7, the operator removes the fuse tube from the lower contact by means of a switch stick. He then refuses the device by loosening the members 9 and i and threading a new fuse link through the fuse tube and thereafter tightening the clamping members on the head of the fuse link. The operator next makes sure that the temporary clamping member indicated at B0 is in the relative position shown in Figure 7. Usually when the fuse tube has dropped to the position shown in Figure '7, gravity will rock the temporary locking member into the position shown in Figure '7. This clamping member consists of a U-shaped member having a long pivot portion 8! pivoted in the main lever and having a short leg portion 62 which is adapted to be rocked over the shouldered portion 83 of the fuse link clamping member 49, see Figure 2. Thereafter the operator places his thumb on the thumb piece 48 of the auxiliary lever 43 and forces such lever inwardly into the position shown in Figure 2 and pulls the fuse link around the auxiliary lever into the position shown in Figure 2, inserting the end of the leader between the portion 50 and the portion 5|. Thereafter he rocks the latching member 60 to the position shown in Figure 2, thereby allowing the clamping member 49 to spring upwardly and clamp the leader of the fuse link in place.

I1; is very easy for the operator to insert the end of the leader between the members 50 and SI while it is held temporarily latched by the mem- Otherwise there would be considerable difficulty in getting the end of the leader between the members 50 and 5|. i

It will be seen that a novel form of drop-out fuse device has been provided in which means are provided for clamping the fuse link in place, in which a flip-out or fuse link extracting means is provided which positively engages and releases the clamping means, and in which the fuse link is withdrawn substantially directly outwardly from the fuse tube and is released while it is still executing its outward motion, thus allowing the fuse link to be thrown or dropped freely from the apparatus.

It will be seen that the fuse tube may be de tached from the stationary portion of the apparatus for refusing and may be repositioned and rocked back into operative position after refusing.

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 drop-out fuse construction comprising a support having upper and lower stationary termL nals, a fuse tube having an upper end detachably locked to said upper stationary terminal, a main lever supporting said fuse tube for drop-out motion, said main lever being pivoted to said support and pivoted to said fuse tube, a fuse link within said fuse tube electrically connecting said upper and lower terminalsand normally restraining said main lever against motion, an auxiliary fuse link fiip-out lever pivoted on said main lever and spring urged outwardly, said fuse link being engaged by said auxiliary fuse link flip-out lever, and spring urged clamping means for clamping the fuse link between said main lever and said clamping means.

2. A drop-out fuse construction comprising supporting means having upper and lower stationary contacts, a fuse tube normally positioned between said contacts, a fuse link extending through said fuse tube and electrically joining said upper and lower stationary contacts, a main lever plvotally supported from said support and plvotally joined to said fuse tube and normally holding said fuse tube in an elevated position .and movable downwardly to lower said fuse tube for drop-out motion, means normally latching said fuse tube in operative position, an auxiliary fuse link flip-out lever pivoted to said main lever and engaging said fuse link, said auxiliary fuse link flip-out lever having a free. end extending inwardly and positioned adjacent the lower portion of said fuse tube and movable substantially directly downwardly with reference to said fuse tube, means for imparting motion to said auxiliary fuse link flipout lever independently of any motion of said main lever, and a spring pressed clamping means for clamping said fuse link directly against said main lever.

3. A drop-out fuse construction comprising a support having upper and lower stationary contacts, latch means, a fuse tube normally positioned between said contacts and-restrained by said latch means, said fuse tube having an open lower end, a fuse link extending through said fuse tube and electrically joining'said upper and lower stationary contacts, a main lever pivoted to said lower stationary contact, an arm carried by said fuse tube and pivoted to said main lever and adapted to be displaced downwardly when said main lever rocks downwardly, an auxiliary lever plvotally carried by said main lever and spring urged outwardly with respect to said main lever, said fuse link being engaged by said auxiliary lever, and spring pressed clamping means for clamping said fuse link against s'aidmain lever.

4. A drop-out fuse construction comprising a support having upper and lowerstationary contacts, latch means adjacent the upper contact,

- a fuse tube normally positioned between said contacts and restrained bysald latch means, said extending through said fuse tube and electrically joining said upper and lower stationary contacts, a main lever pivoted to said lower stationary contact, an arm carried by said fuse tube and pivoted to said main lever and adapted to be displaced downwardly when said main lever rocks downwardly, an auxiliary lever pivotally carried by said main lever and spring urged outwardly with respect to said main lever, said fuse link being engaged by said auxiliary lever, and clamping means for clamping the fuse link against said main lever.

5. A drop-out fuse construction comprising a support having upper and lower stationary contacts, latch means, a fuse tube normally positioned between said contacts and restrained by said latch means, said fuse tube having an open lower end,

'a fuse link extending through said fuse tube and fuse link with reference to said main lever, the

spring pressure against said clamping means being relieved prior to the time said auxiliary lever has completed its outward rocking motion.

6. A fuse construction comprising a support having stationary contacts, a fuse tube normally positioned between said stationary contacts, said fuse tube having an open end, a fuse link extending through said fuse tube and electrically Joining .said stationary contacts, an outwardly biased main lever pivoted to one of said stationary contacts, an auxiliary lever pivotally carried by said main lever and spring urged outwardly with respect to said main lever, said fuse link being engaged by said auxiliary lever, clamping means for clamping said fuse link with respect to said main lever, a spring interposed between said clamping means and said auxiliary lever, and means carried by said auxiliary lever for engaging said clamping means when said auxiliary lever is nearing the completion of its outward rocking motion whereby said auxiliary lever and clamping means move as a unit during the-final portion of the outward rockingmotion of said auxiliary lever. I

7. A fuse construction comprising a support having stationary contacts, a fuse tube normally lever having pivotal motion with respect to said fuse tube and biased for outward motion, said fuse link being engaged by said fuse link flip-out lever, spring pressed clamping means forclamping'said fuse link, the spring pressure of said clamping means being relieved prior to the completion of the stroke of said fuse link flip-out lever, and latching means for temporarily latching said clamping means in open position to facilitate refusing, said latching means being manually releasable.

9. A drop-out fuse construction comprising a support having upper and lower stationary contacts, latch means, a fuse tube normally posi tioned between said contacts and restrained by said latch means, said fuse tube having an open lower end, a fuse link extending through said fuse tube and electrically joining said upper and lower stationary contacts, a'main lever pivoted to said,

lower stationary contact, an arm carried by said fuse tube and pivoted to said main lever and adapted to be displaced downwardly when said main lever rocks downwardly, an auxiliary lever pivotally carried by said main lever and spring urged outwardly with respect to saidmain lever, said fuse link being engaged by said auxiliary lever, spring pressed clamping means for clamping said fuse link with reference to said main lever, the spring pressure against said clamping means being relieved prior to the completion of the stroke of said fuse link flip-out lever, and latching means carried by said main lever for temporarily latching said clamping means in open position to facilitate refusing.

10. A drop-out fuse construction comprising a support having upper and lower stationary contacts, said upper contact including a stationary portion having oppositely extending divergent cam portions and a U-shaped spring contact having arms embracing said cam portions and tending to move downwardly on said cam portions,

tact including a spring contact urging said fuse tube towards rocking motion,.lever means norpositioned between said stationary contacts, said fuse tube having anopen end, a fuse link extending through said fuse tube and electrically Joining said stationary contacts, a fuse link flip-out 1 lever having pivotal motion; with respect to said fuse tube and biased for outward motion, said fuse link being engaged by said fuse link flip-out lever, spring pressed clamping means for clamping said fuse link, the spring pressure of said clamping means being relieved prior to the com,- pletion of the stroke of said fuse link flip-out lever, and latching means for temporarily latch- 7 support having upper and lower contacts, a fuse 'mally supporting said fuse tube in latched position and biased to fuse tube releasing position,

and a fuse link within said fuse tube normally restraining said lever means and releasing said lever means when said fuse link is ruptured.

11. A drop-out fuse construction comprising a tube, a fuse link within said fuse tube and projecting outwardly from said fuse tube, a member rigidly secured to thelowen portion of said fuse tube, a lever pivotally supported from said lower contact and pivotally joined to said member, said fuse tube being adapted to drop outsition, said lever being biased towards downward ing said clamping means in openposition to facil'itate refusing.

-8. A fuse construction comprising, a support having stationary contacts, a fuse tube normally positioned between said sta'tionarycontacts, said fuse tube having an open end, a fuse link extending through said fuse tube and electrically joining said stationary contacts, a fuse link flip-out rockingmotion and being normally restrained by said fuse linkand being released upon rupture of said fuse link, said lever having a striking portion adapted to strike said lower contact when said lever rocks downwardly, and said member having a striking portion adapted to strike said lever at a point substantially directly transversely opposite the said striking portion of said lever when said fuse tube rocks downwardly.

support having upper and lower contacts, a fuse tube, a fuse link within said fuse tube and projecting outwardly from said fuse tube, a member rigidly secured to the lower portion of said fuse tube, a lever pivotally supported from said lower contact and pivotally joined to said member, said fuse tube being adapted to drop outwardly when said lever rocks from normal position, said lever zeing biased towards downward rocking motion and being normally restrained by said fuse link and being released upon rupture of said fuse link, said lever having a striking portion adapted to strike said lower contact when said lever rocks downwardly, and said member having a pair of striking portions located on opposite sides of said fuse tube and adapted to strike said lever at points substantially directly transversely opposite the said striking portion of said lever when said fuse tube rocks downwardly.

13. A fuse construction comprising a support having stationary contacts, a fuse tube normally positioned between said stationary contacts, said fuse tube having an open end, a fuse link extending through said fuse tube and electrically Joining said stationary contacts, a pivotally mounted fuse link flip-out lever spring urged outwardly from said fuse tube, said fuse link being engaged by said fuse link flip-out lever, clamping means for clamping said fuse link, a spring interposed between said clamping means and said fuse link nip-out lever, and means carried by said fuse link flip-out lever for engaging said clamping means when said fuse link flip-out lever is nearing the completion of its outward rocking motion, whereby said fuse link flip-out lever and said clamping means move as a unit during the final portion of the outward rocking motion of said fuse link flip-out lever.

12. A drop-out fuse construction comprising a- 14. A drop-out fuse construction comprising a support having upper and lower stationary terminals, a fuse tube having an upper portion detachably locked to said upper stationary terminal, a main substantially horizontally extending lever supporting said fuse tube for drop-out motion, said main lever being pivoted to said support, a fuse link within said fuse tube electrically connecting said upper and lower terminals and extending outwardly from the lower end of said fuse tube and normally restraining said main lever against motion, an auxiliary fuse link flip-out lever pivoted on said main lever and substantially paralleling said main lever, and spring ,means for urging said auxiliary fuse link flip-out lever towards motion with reference to said main lever.

15. A drop-out fuse construction comprising a support having upper and lower stationary terminals, a fuse tube having an 'upper portion detachably locked to said upper stationary terminal, a main substantially horizontally extending lever supporting said fuse tube for drop-out motion, said main lever being pivoted to said support, a fuse link within said fuse tube electrically connecting said upper and lower terminals and extending outwardly from the lower endof said fuse tube and normally restraining said main lever against motion, an auxiliary fuse link flip-out lever pivoted on said main lever and substantially paralleling said main lever, said auxiliary fuse link flip-out lever having a free end extending inwardly and positioned adjacent the lower portion of said fuse tube and movable substantially directly downwardly with reference to said fuse tube and having a manipulating thumb piece.

WILLIAM O. SCHULTZ.

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