US1853209A

US1853209A - Fused cut-out

Info

Publication number: US1853209A
Application number: US49189A
Authority: US
Inventors: Herz Alfred
Original assignee: Individual
Current assignee: Individual
Priority date: 1925-08-10
Filing date: 1925-08-10
Publication date: 1932-04-12
Anticipated expiration: 1949-04-12

Description

Apnl 12, 1932. A. HERZ 1,853,209

FUSED CUT-OUT l Filed Aug. l0. 1925 3 Sheets-Sheet l A. HERZ FUSED CUT OUT April 12, 1932.

5 3 Sheets-Sheet Filed Aug. l0, 192

MOL/ABLE April l2, 1932. A. HERZ 1,853,209

FUSED CUT-OUT 3 Sheets-Sheet 3 Filed Aug. 10, 1925 Patented Apr. 12, 1932 UNITED STATES PATENT OFFICE ALFRED HERZ, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-HALF TO EDMUNI) O. SCHWEITZER, F CHICAGO, ILLINOIS FUSEI) CUT-OUT Application led August 10, 1925. Serial No. 49,189.

My invention relates to fused cut-outs and may be characterized as an improvement upon the type of cut-out disclosed in my copending application, Serial No. 643,854, tiled June 1, 1923.

The electrical circuit through devices of this sort is generally U-shaped and I lind that the magnetic lield in its tendency to straighten out the current flow, as well understood in the art, tends to separate the co-operating terminals or contacts of the device and to increase the violence of the explosion. I ind, among other things, that when devices of this sort are subjected to heavy short cir cuits there is a severe burning at the contacts and at times an explosion.

The objects of my present invention are to eliminate the burning at the contacts, also to overcome any tendency to increased violence at which the device is thrown on heavy short circuits and to prevent separation of the cooperating terminals or contacts of the device due to the magnetic action which accompanies the flow of current through the device.

wWith the foregoing in view I provide for holding the separable contacts or terminals of the device rigidly and immovably in electrical connection. The base of the U-shaped circuit through the cut-out instead of being `l spring or yieldably held as before is held rigid or stationary, so that it is immovable under the magnetic action which accompanies the low of current through the device. The circuit between the lower member or base 'f of the Ll and the upper legs thereof may be closed by yieldable contacts, preferably of the multiple leated brush type. These may have a scraping or self-wiping action as they are pressed into cci-operation with the co-operating contacts ot the device and they form a yielding connection to insure good irm contact at all times without having the entire bottom or base of the U yieldably held with the accompanying diiiiculties above set out.

" The provision for doing this may also provide for swinging the movable contacts laterally in separating them from the stationary contacts and a greater or separation may be provided for in this manner.

Further objects of my invention are to reentorce at least one of the dampening or coinpression blocks against being broken by the explosion which accompanies blowing of the fuse, also to leave the faces clean and without deposits of fused metal after blowing of the fuse, and to provide a generally improved and simplified construction and suitable means for holding the lower or separable terminals rigidly and irmly in place and for conveniently separating them from and moving them into engagement with the cooperating contacts of the cut-out.

To apprise those skilled in the art with the construction and operation of my invention, I shall now describe a speciiic embodiment of the invention in connection with the accompanying drawings which form a part of the present specilication.

ln the drawings:

Figure 1 is a vertical section through a cutout embodying my present invention;

Fig. 2 is a somewhat reduced vertical section taken on the line 2 2 of Fig. 1;

Fig. 3 shows a development of the cam means for vmoving the lower terminals into engagement with and releasing them for separation from the upper contacts and for holding them rigidly and immovably in cooperation therewith;

Fig. 4 is a horizontal section taken on the line 4-4 of Figure 1;

Fig. 5 is a horizontal section taken on the line 5-5 of Figure 1;

Fig. 6 is a plan view of the lower cam part taken on the line 6-6 of Fig. 2;

Fig. 7 is an enlarged detail section transversely through the upper contact carrying block and through one of the contacts carried thereby on the line 7-7 of Fig. 1;

Fig. 8 is a plan view of the fuse, and

Fig. 9 is a transverse section through the active portion of the fuse taken on the line 9-9 of Fig. 8.

Referring to the drawings, the container for the cut-out preferably employes the diving-bell principle for excluding moisture from the inside. This container may be o't he type more fully disclosed in my hereinbefore referred to co-pending application comprising a vessel 5 having an annular wall extending up within an inverted shell or cover 6, the vessel 5 being closed at its bottom and open at its top and the cover 6 having a closed top and open bottom. These shells or container parts 5 and 6 are preferably light in weight and of great strength. Along its lower edge, the vessel 5 is shown as having an outwardly extending annular flange 8 and the cover or shell 6 is shown as having a cooperating annular flange 9. rl`he two parts may be clamped together by wing or thumb bolts 10, which bolts l may be mounted in tubular bosses 12 formed integral with and depending from* the bottom of the flange 8. The shanks of the bolts 10 may be enlarged at their upperl ends and threaded into the flange 9 and below said threaded heads said shanks may be reduced with set Screws 111 threaded radially through the bosses 12 to cooperate with the threaded heads of the Shanks of the bolts 1() when said heads are threaded out of engagement with the flange 9 for the purpose of holding the bolts 10 against complete displacement from the flange 8.

The upright wall of the vessel encloses they cut-out mechanism and is adapted to hold a body or bath of liquid such as transformer or other suitable insulating oil or an arc extinguishing and insulating liquid such as carbon tetrachloride or liquid such as disclosed in U. S. Patent No. 1,319,907, granted October 28, 1919, to Edmund O. Schweitzer and Nicholas J. Conrad.

The manner in which moisture is excluded from the inside by means of the construction above set out is more fully explained in my above referred to copending application and will not be gone into detail here. Suffice it to say that the construction shown is illustrative of a structure embodying the divingfbell principle for excluding water and moisture from the inside, and that the utilization of this principle is especially7 advantageous where the device is to be used for underground or subway work, where moisture is especially prevalent.

Passing loosely through a lug or boss 15 formed integrally with and projecting radially from one side of the shell 6 and threaded at its lower end into the flange 8 of the part 5 is a relatively long bolt or rod 16. A nut 18 threaded .upon the lower projecting threaded end of the rod 16 firmly secures the lower end of si id rod in the flange 8. The bolt 16, the upper end of which has a head or enlargement 20, permits the vessel or part 5 to be dropped from the cover or part 6 upon screwing the bolts out of' engagement with the flange 9, to a point at which the upper edge oit the vessel 5 clears the lower edge of the inverted shell or cover 6, whereupon the vessel 5 may be swung or rotated about the axis of the bolt 16 into position where the interior is exposed to view and i'or access without mechanically disconnect` ing the vessel 5 from the shell or cover 6, and without entirely removing the bolts 10 from the flange 8.

A helical spring 22 resting upon the lug or boss and surrounding the rod or bolt 16 is engaged by the head 20 of the bolt 16 as the vessel 5 nears the lower limit of its movement. rIbis spring 22 cushions the downward movement of the vessel or part 5, yieldingly lilniting relative longitudinal .movement between the casing parts and serving as a cushion or bumper to prevent cracking or breaking of the parts by dropping or too quick downward movement of the vessel 5.

The top wall 25 of the cover or part 6 has pair of integral tubular bosses 26 opening into the container. Abritting the upper ends of each of the bosses 26 and forming a conjiinuation thereof is a tubular wiping nipple or sleeve 28. The lower end of each of the nipples 28 is externally flanged at 29, and threaded at 30 externally upon the bosses 26 are coupling members 32 which may be in the form of pipe unions, as shown. These coupling cr union members 32 have flanges at their upper ends for co-operation with the flanges 29 to clamp the wiping nipples firmly upon the upper ends of the bosses 26 and provide tight joints between them and said bosses 26 as the coupling or union members are threaded down upon said bosses.

The conductors 35 leading into the cut-out are in this case lead covered cables provided with an insulation wrapping or covering 36 between the sheaths 38 and the conductors proper. The cable sheaths 38 are removed or peeled back from the inner ends of the cond ctors 35 and tight joints may be provided between said cable sheaths 38 and the outer ends ot the wiping nipples 28 by wiped solder joints 40, such as well known in the art. The outer ends of the wiping nipples 28 may be tapered at 42 for this purpose, as shown.

The foregoing inlet. structures for the conductors 35 effectively prevent the ingress or entrance of moisture to the cut-out within the container through the inlets through which the conductors are led in. Atthe same time the foregoing construction permits convenient insertion of the conductors and convenient sealing of the openings through which they are led. Convenient removal and replacement of the nut or coupling members 32, as well as convenient removal and replacement. of' the wiping nipples is also permitted in the event that any of said parts become cracked or broken, or it otherwise becomes desirable to replace or change the same.

For the purpose of' fastening or attaching the cut-out to a cross arm, pole, wall or other suitable support, the container may be provided with suitable mounting lugs 45 as shown. These lugs 45 may be formed intei contacts 55.

gral with the shell or cover 6 and may be slotted at 46 to receive bolts or other' suitable fastening means.

A block of insulation 50, which may be bakelite or any other suitable or preferred insulating material, is secured within the shell or cover 6 to the lower side of the closed top thereof, as by means of screws 52 which may have their heads countersunk into the lower or bottom surface of the block 50, the upper ends of said screws 52 being threaded into the top wall 25 of the shell or cover 6. rllhere is preferably one of these screws at each of the' four corners of the block or table and each is preferably surrounded by a sleeve 54 of bakelite, or other suitable insulating material, the sleeve 54 being interposed between the top wall 25 of the shell 6 and the table or block 50 and spacing the block 50 properly below the top wall 25.

The insulating block or table 5() supports two stationary contacts 55, which comprise metallic socketed members mounted in open- .i ings in the block 50 in axial alignment with the inlets through the tubular bosses 26. The lower ends of the contacts 55 terminate in flanges or heads 56 which engage the underside of the block 50 and provide flat heads for engagement with the fuse terminals.

The heads 56 of the contacts 55 may have suitable holes or openings therethrough as shown to prevent accumulation of foreign particles within the internal sockets of said Fitting into the sockets of each of the contacts 55 is a thimble contact 58. These thimble contacts 58 are internally recessed or socketed to receive the lower bared ends of the conductors 35, the insulation 36 a, on said conductors being peeled back or removed sufliciently atthe terminals of the conductors for this purpose, and the thimble contacts 58 being soldered or otherwise suitably secured upon the bared ends of the conductors 35. The upper ends of the thimble contacts 58 may be flanged at 60 to engage the upper ends of the contacts 55 and suitable capstan screws 62 may be threaded through the block 50 from the side, as shown in Fig. 2, and through the sleeved portions of the contacts 55 into engagement at their inner ends in grooves 63 formed peripherally about the thimble contacts 58. The screws 62 thereby hold the contacts 58 securely in the socket portions of the contacts 55 and in proper electrical engagement therewith, and at the same time hold the contacts 55 in the openings provided in the block 50. The heads of the screws 62 may have the usual l openings to receive a rod or pin from the upper end of the shell 5 so that said screws may be conveniently turned from the upper end of the shell 5 when it is swung into position clear of the part 6. Contacts 55 and thimbles 58 are formed of brass or other suitable material having good conducting and wearing qualities.

A transverse partition 65, also preferably of bakelite or other suitable insulating material, is mounted in upright position upon the upper surface of the block 50, as by means of screws (not shown) and extending up to the under surface of the top wall 25 of the shell 6 between the contacts associated with the block 50 provides an insulating barrier between said contacts and the ends of the conductors 35. This insulating barrier 65 mechanically strengthens the block 50 and prevents electric splashing or flash overs between the ends of the conductors 35 and the contacts associated therewith. The sleeves 54 properly position the block 50 without interfering with ready and free access of the oil, or other insulating liquid in the container to the contact mechanism.

The fuse which may comprise a small flat strip of relatively soft or fusible metal, as shown in Fig. 8, is disposed between the upper and lower compression or dampening blocks 7l and 72. Screws 73, the upper headed ends of which may be countersunk in the upper surface of the block 7l pass through said block 71 and have threaded engagement at their lower ends in suitable cylindrical nuts 74, which nuts have fiat heads 75 at their lower ends. The heads 7 5 may be provided with screw driver slots 76. The upper ends of the nuts 74 are cut off square at 78 to engage straps 80, which may be of bronze, brass, copper, or other metal having copper conducting properties.

The straps extend around the ends or sides of the lower compression block 72, preferably around the side, as shown in Fig. 2, because of the greater room for attachment there, in the particular embodiment shown. They7 perform the dual purpose of making good contact with the ends of the fusible link 70 and retaining cylindrical nuts 74 against complete displacement from the block 72, even w ien said nuts are threaded out of engagement with the screws 73. The lower leg of each strap 80 is slotted at 8l to engage around the reduced portion 82 of the nuts 74, and the shoulder portion 83 formed by the reducedL portion 82 prevents the escape of the nuts through the slots. rlhe lower legs of the straps are preferably turned down slightly, as shown in Fig. 2, to engage the heads 75 of the nuts 74, and by the springiness of the straps tending to urge the nuts 74 downwardly.

The upper legs 84 of the straps 80, which legs 84 make contact with the ends of the fuse 70, have openings or holes through which the shanks of the screws 73 pass and the straps 8O may be held in place on the block 72 by means of relatively small wood screws 85. The shoulders 83 on the nuts 74 engage the walls of the straps 80 along the slots 81 in the to draw the screws 73 downwardly,

lower legs thereof, when the nuts 74 are loosened from the screws 7 3, so that the nuts 74 cannot be lost from the block 72.

The terminals or ends of the fuse have Y slots S6 (Fig. 8) through which the shanlrs of the screws 73 extend. Between said slotted. ends is the active portion of the fuse or the portion to which the blowing or fusing` usually confined. This portion may be duced or restricted, as shown in Fig. tl.

The circuit between the ends of the fuse 70 and the upper contacts 55 closed through terminals or contacts 87, which are preferably of the multiple leaf brush type, having suitable springiness and preferably of sheet bronze, although of course a y other suitable or preferred conducting material maj," be einployed. The contacts are of generally llshaped formation, as shown in The lower legs 88 of these contacts 87 extend between the ends of the fuse 70 anc the under surface or bottom of the block 71, and hav openings or holes through which the shan .1 of the screws 78 pass or extend. By threading the nuts 74 upwardly upon the screws 73, the engagement of the upper ends of said nuts with the upper legs of the straps S0 forces said legs upwardly and clamps the ends of the fuse 70 and the lower legs of the contacts 87 in good electrical contact and botl with the straps 80 securely and firmly between the upper ends of the nuts 74 and the bottom of the block 71.

The tightening up of the nuts 74 also tends ancl through the heads of said screws 7f3 the bloclY 71 is clamped down upon the lower legs 88 of the contacts 87. The nuts 74 lit loosely in the openings 89 in the block r'2, as shown, so

that while the block 72 and nuts '74 are clamped firmly together with the terminals of the fuse and contacts 87 and upper legs of the straps 80 clamped securely between them, the block 72 is not clamped to the block "71 by the nuts 7 4 and coope ating screws 7i' but is relatively free or floating on the nuts 74 between the fuse 70 and the heat-.s 75 of the nuts. The upper legs 90 of the contacts 87 make yielding Contact with the heads 5G of the contacts 55, the heads 56 being preferably relatively large for proper contact with the contacts 87, and to allow for any slignt lost motion or the like in turning the lower contact parts, as will be hereinafter descriliie-d.

For the purpose of reenforcing and preventing breaking of at least one of the ce ipression or dampening

blocks

71 and 7 un r the explosions which accompany blowinoo` the fuse, especially the upper block which -is not supported at any point but the enus.y

but preferably both blocks, I provide an iinproved compression block construction. I form the compression or dampeni'ng surfaces of either one or both (both being shown) of relatively thin blocks 92 of asbestos anfL cement board, asbestos, or the like, which may be treated as more fully set out in Patent No. 1,479,558, granted January 1, 1924, to Edmund O. Schweitzer and myself by boiling said blocks 92 in transformer oil until the oil has penetrated all parts of the block. As before, this treatment apparently removes some of the objectionable minerals which are contained within the libres of the asbestos, and the resulting blocks 92 are highly resistant to the action of the heat and explosions. Then to reenforce one or both of said blocks 92 I provide blocks 93 of a material having greater tenacity than the blocks 92 and I back the blocks 92 therewith. I find that maple wood is highly desirable for the blocks 93, although any other material having the required qualities may be employed. The blocks 93 are preferably treated in the same manner as the blocks 92 and the resulting combination provides blocks highly resistantto the action of the heat and explosions and highly resistant to cracking or breaking, even under uneven heating.

The compression blocks 71 and 72 are mounted in a generally U-shaped cradle 94. This cradle 94, which may be of wood, comprises a bottom block or member 95, to the upper surface of which are fastened as by means of suitable wood screws 96 the up- 9.) right or vertical side pieces 97. These side pieces form the upright legs of the U. They are at opposite ends of the block 95 and straddle the sides of the

blocks

71 and 72.

For the purpose of holding the fuse metal 1GO and preventing the arc of successive fuses following through the metal of a preceding fuse, I cover the reduced or active portion of the fuse link 70 with a sleeve or cover 100, preferably of sheet asbestos. In blowing the fuse metal is thereby not left on the surfaces of the dampening or compression blocks for the arc of succeeding fuses to follow through, but is removed with removal of the fuse. fuse also renews the surfaces of the blocks 92. The cover or sheath 100 is preferably of sheet asbestos and it may be treated in transformer oil, as explained in connection with the blocks 92. It may be conveniently '.J.; placed upon the reduced portion of the fuse by taking a sheet or strip of treated sheet asbestos, folding it over the portion of the fuse to be covered, and stitching or otherwise securing the edges thereof together, as :.Jli;

Hence, renewal of the .'.p

surface 107 for cradle or rocking engagement with the bottom of the cradle 94 to force the block 72 uniformly into crushing engagement with the fuse, and the contacts uniformly into engagement with the contacts 55 even in spite of disalignment or irregularities in the parts. The upper surface of the cam member 105 also has integral upright pins or projections 108 which engage in recesses in the bottom of the bottom member 95 of the cradle 94, thereby connecting the cam member 105 and the cradle 94 against relative rotation.

The cam member 106 is secured non-rotatably to the bottom of the vessel 5, as by means of screws 109. A shaft 110 extends axially through the bottom of the vessel 5 and through the cam member 106 and is secured at its upper end in the cam member 105 as by means of a diametrical pin 111 to turn said cam member 105 with the shaft 110 upon rotation thereof. The passage of the shaft 110 through the bottom of the vessel 5 may be packed by a gland comprising a sleeve 112 having an axial bore through which the shaft 110 extends, and a reduced end entering an opening in the bottom wall of the vessel 5. The sleeve 112 has a flange 113 which may cover and seal the openings into which the screws 109 are threaded and the periphery of this flange may be welded at 114 to the bottom of the vessel 5. A packing sleeve 115 surrounds the shaft 110 and is threaded into the sleeve 112 and suitable packing is interposed at 116 between the upper end of this sleeve 115 and the sleeve 112 to provide a tight joint about the shaft.

A gland nut 118 is threaded upon the lower end of the sleeve 112' and additional packing (not shown) may be disposed in this nut and between it and the sleeve 112, as a further resistance to leakage.

A cap member 120 is secured upon the lower end of the shaft 110 as by means of a nut 121, and interposed between the nut 118 and the cap member 120 is a coiled spring 122 which urges the shaft 110 and cam member 105 secured thereto downwardly when the cam member 105 is turned to free it from that engagement with the cam ineinber 106 which holds the parts rigidly in closed position. The upper edge of the cap member 120 and the nut 118 may have cooperating tapered surfaces, and the lower end of the shaft 110 is squared or non-circular at 123 to receive a removable handle 124 for turning the shaft 110 from below. l

A developed view of the upper cam is shown in Fig. 3 with a similar view of the lower or stationary camy disposed below it. The lower or stationary cam member has lower-annular surfaces 125, upper annular surfaces or raised portions 126, inclined surfaces 127, and vertical shoulders 128. '.llhe upper movable cam member 105 has similar and complementary surfaces and shoulders. rihe low surfaces 125 are at diainetrically opposite points and in the particular einbodiment shown each occupies substantially oneeighth of the upper peripheral dimension of the cam. The inclined surfaces 127, slioulders 128. and upper surfaces 1 .6 are also at diametiically opposite points, the inclined surfaces occupying about one-eighth and the upper surfaces substantially one-quarter each of the peripheral dimension of the cam.

F rom the foregoing, it will be apparent that with the cam surfaces in register, as shown in Fig. 8, the lower contacts 87 are released for separation from the contacts 55. To close the cut-out, assuming a new fuse has just been inserted for example, the handle 124 is placed upon the shaft 110 and this shaft rotated, in the direction indicated by the arrow in Fig. 1. The cradle 94, compression blocks, fuse and contacts associated therewith, turn with the cam member 105 which rotates with the shaft 110 and siinultaneously the inclined surfaces of the cam 105 ride up on the surfaces 127 of the cam 106. rfhis forces the block 7 2 up into crushing engagement with the fuse 70, and through the cradle and this block the upper legs 90 of the brush contacts 87 into firm contact with the contacts 55 as the contacts 87 are turned into position for proper co-operation therewith. 1t is to be noted that the contacts 87 straddle opposite sides of the block 71, so that each approaches its contact 55 from the base end of the U formation of the contacts 87, and that when the lower surfaces of the upper movable cam reach the upper surfaces 126 of the lower cam, as shown in Fig. 2, the lower contact parts are all held in stationary and unyieldingly in closed position. The compression blocks 71 and 72 are turned through the upright legs 97 of the 4cradle and the greater lengths of the surfaces 126, together with the wide heads 56 of the contacts 55, permitting some lost motion between the movable cam and the compression blocks and contact parts associated therewith.

`When the fuse blows, separation of the cooperating contacts by the magnetic action which accompanies the flow of current through the device is positively prevented by the rigid and stationary manner in which the lower parts are held in closed position, and the violence of the action is decreased and burning of the contacts is eliminated. At the same time, the device may be conveniently opened and yielding contact had between the upper legs 90 of the contacts 87 and the heads of the contacts 55 to assure good contact at all times.

The shoulders 128 of the cam members 105 and 106 limit rotation of the parts to open position, and the lateral and separating movement of the movable contacts increases the gap and the travel through the body of liquid.

It is to be understood that the facing blocks 92 may be of limestone, as set out in Patent No. 1,263,610, granted April 23, 1918, to Edmund O. Schweitzer and myself.

I claim:

1. In a device of the class described the combination of a pair of contacts, a generally U-shaped circuit connection having a base and leg portions with yieldable contacts between said leg portions and said first contacts, said U-shaped circuit connection having movement for making and breaking the engagement between said yieldable contacts and said first contacts and means for holdingl the base portion of said U-shaped circuit against separating movement from said first contacts when said yieldable contacts are in engagement therewith.

2. In a device of the class described, the combination of a pair of contacts, a generally U-shaped circuit connection having a base and leg portions with yieldable contacts between said leg portions and said first contacts, said U-shaped circuit connection having movement for making and breaking the engagement between said yieldable contacts and said first contacts, means for holding the base portion of said U-shaped circuit against separating movement from said first contacts when said yieldable contacts are in engagement therewith, a fuse in the base of said U-shaped circuit connection and compression blocks lying on opposite sides of the fuse.

3. In a device of the class described, the combination of a pair of contacts, a fuse having yielding terminal contacts movable into and out of engagement with said first contacts, means for supporting the fuse and the yielding terminal contacts, and means for preventing separating movement of the fuse and supporting means from said first contacts when said yielding contacts are in engagement therewith.

4. In combination, a pair of relatively stationary contacts, a pair of block members, a pair of terminal members, a fuse interposed between the block members and connecting the terminal members, said terminal members being mechanically independent of and separable from said contact members, a pair of yielding contacts for electrically connecting said terminal members and said first contact members, and means for holding said yieldable contacts in engagement with said first contacts and for simultaneously holding the fuse and terminals between which said fuse is connected against separating' movement from said relatively stationary contact members.

5. In combination, a container comprising a pair of container parts, means for holding said parts together, a pair of contacts mounted on one part, a pair of terminals mechanically independent of said contacts, a fuse connected between said terminals, yielding connections between said terminals and said first contacts, means for supporting the fuse and said terminals, and means for holding said fuse and terminals against separating movement from said first contacts.

6. In combination, a container, a cover therefor, a pair of conductors passing through said cover, a. first pair of contacts mounted in insulated relation on the cover, a pair of terminals, a support for said terminals, a fuse link connecting said terminals, yielding contacts for electrically connecting said terminals and said first contacts and means below said support for preventing separating movement of said terminals and fuse from said first contacts when said yieldable contacts are in engagement therewith.

7 In combination, a container, a cover therefor, conductors passing through the cover and having contacts within the container, a pair of compression blocks, a fuse between said blocks, a cradle support for said blocks, cam means below the cradle for raising same and for preventing downward movement thereof, and yieldable contacts connected to the terminals of the fuse and co-operable with said first contacts to place the fuse in series relation with said conductors.

8. In an electric circuit, the combination of a pair of contacts, a generally U-shaped circuit connection having a base portion and leg portions movable into and out of electrical contact with said contacts, and flexible self-expanding contacts between the leg portions of said circuit connection and said first contacts.

9. In combination, a container, a cover therefor, conductors entering the container and having contacts therein, a pair of compression blocks, a fuse between said blocks, contacts for said fuse cooperable with said first contacts, said contacts being self-expanding under the magnetic forces accompanying a flow of current through the device, a support for said blocks, means for holding the compression blocks, fuse and a fuse support against separating movement from said first contacts with the fuse contacts in contact with said first contacts and for freeing said compression blocks and fuse and swinging same laterally to separate said fuse contacts from said first contacts.

10. In combination, a container, a cover therefor, a relatively stationary block secured to the bottom of the cover, a pair of relatively stationary contacts mounted in said block, conductors passing through the cover and connected to said stationary contacts, a movable fuse support having yieldable contacts for wiping engagement with said first contacts, a fuse connected between said latter contacts, and cam means for the fuse support for moving said latter contacts into engagement with said first contacts and for holding same against separation therefrom.

11. In combination, a fuse, a compression block lying on one side of said fuse, a block lying on the other side of said fuse, a body of liquid enclosing said fuse and said compression blocks, a substantially fluid tight casing enclosing the body of liquid, and means for moving one of said blocks toward the other and for holding same against separation therefrom.

12. In combination, a pair of contacts, a compression block having a pair of threaded studs, nuts threaded on said studs, a second compression block having floating mounting on said nuts, yieldable contacts having legs clamped between said first block and said nuts, a fuse lying between said blocks and having its terminals clamped with said contacts and in electrical connection therewith, and means for moving said second block toward said first block and said second contacts into engagement with said first contacts, and for holding same against separation therefrom.

13. In combination, a container, a cover therefor, circuit terminals within the container, and means operable externally of the container with said cover in closed position for moving said terminals into closed circuit relation and for holding same rigidly in said relation.

141-. In combination, a container, conductors entering the container and having contacts therein, a pair of compression blocks, a fuse between said blocks, a cradle support for said blocks, second contacts connected to the terminals of the fuse and co-operable with said first contacts, a cam having connection with said cradle to turn the cradle with the cam, means operable externally of the container for turning said cam, and a relatively stationary cam co-operating with said first cam to move said second contacts into engagement with said first contacts upon rotation of said first cam.

15. In combination, a container, relatively stationary contacts therein, a fuse mounting having movable contacts co-operable with said first contacts, a fuse connected between said latter contacts, cam means for holding said movable contacts in engagement with said first contacts, and means for turning said cam means to swing said movable contacts laterally and free same for separation from said relatively stationary contacts.

16. In a circuit interrupter, a compression block, having a surface forming member composed of asbestos board boiled in oil, and a similarly treated block of wood backing and reenforcing said surface forming member.

17. In combination, a fuse, a compression block having a dampening surface exposed to said fuse, and means for preventing deposit of fused metal on said dampening surface and for clearing said surface with removal of the fuse.

18. In combination, a tank, a cover for the tank, a pair of contacts mounted upon the under side of the cover, a compression block underlying said contacts, a pair of terminals carried thereby, self-expanding contacts between said terminals and said first contacts, a second compression block beneath said first lock, a fuse interposed between said blocks and connected between said terminals, and means underlying said second compression block for holding same against movement from said first contacts.

19. In combination, a pair of compression blocks, a pair of terminals secured in one of said blocks, a fuse gripped between said blocks and connected between said terminals, and a pair of generally U-shaped self-expanding spring contacts connected with said terminals with one leg of each of said contacts secured between said compression blocks and thel other leg overlying the opposite side of one of said blocks.

20. In an electric circuit interrupter, two insulator blocks, a conducting member be.- tween said blocks, means for locking the blocks together, and a spring contact for establishing a circuit to the conducting lnember, one end of said spring contact extending between the blocks into engagement with the conducting member and the other end constituting a yielding contacting surface.

In witness whereof, I hereunto subscribe my name this 7th day of August, 1925.

ALFRED HERZ.