US3198913A

US3198913A - Electric fuses and fuse holders therefor

Info

Publication number: US3198913A
Application number: US95180A
Authority: US
Inventors: Harris I Stanback
Original assignee: Square D Co
Current assignee: Schneider Electric USA Inc
Priority date: 1961-03-13
Filing date: 1961-03-13
Publication date: 1965-08-03
Anticipated expiration: 1982-08-03

Description

Aug. 3, 1965 H. l. STANBACK 3,198,913

ELECTRIC FUSES AND FUSE HOLDERS THEREFOR Filed March 13, 1961 3 Sheets-Sheet l INVENTOR. jawrzgsfjwac/ "aw aw Aug. 3, 1965 H. I. STANBACK 3,198,913

ELECTRIC FUSES AND FUSE HOLDERS THEREFOR Filed March 13, 1961 3 Sheets-Sheet 2 J24 1Z4 INVENZ'OR. Y

$4755 mWwIfiQ/wm/Q BY FIE. 1E k Aug. 1965 H. l. STANBACK 3,198,913

ELECTRIC FUSES AND FUSE HOLDERS THEREFOR Filed March 13, 1961 3 Sheets-Sheet 3 IN VEN TOR.

United States Patent 0 3,198, 13 FLEECE-EEC A l) FUSE HOLDERtl THEEEFGR Harris l. Stanhacir, Lexington, K assignor to Signer-e D Company, Ridge, lih, a corporation of Michigan Filed Mar. 13, lid-6i, der. No. 95,180 2 Claims. (iii. Zdd-llf) This invention relates to electric cartridge-type fuses and fuse holders theref More particularly, it relates to fuses of special construction adapted to cooperate with fuse holders of special construction. The specially constructed fuses of this invention will also cooperate with or fit standard fuse holders, but the specially constructed fuse holders of this invention will not accommodate standard fuses, unless installed specifically to do so in a manner to be described.

The invention is particularly useful when it is desired to connect a load to a power source having a higher short circuit capacity available than can safely be connected to a standard fuse. in such instances it would be desirable from the standpoint of safety to provide means for preventing installation of a standard fuse, and to accomplish this purpose a fuse holder having one of the special constructions of my invention may be used, and a fuse having a higher current interrupting capacity than a standard fuse and adapted to cooperate with the special fuse holder may be placed therein, the special fuse holder not accommodating a standard fuse with a too low current interrupting capacity.

The specially constructed fuses of my invention will also fit standard fuse holders and may be used in place of standard fuses in existing installations having standard fuse holders when a change in power supply has made higher short circuit capacity available than can safely be connected to a standard fuse. Thus a knowledgeable user may save the expense of replacing the standard fuse holders. Further, because the specially constructed fuses of my invention can be used in standard fuse holders, it is not necessary to manufacture and stock two kinds of fuses with high current interrupting capacity, one kind for new installations having specially constructed fuse holders which will not accommodate standard fuses, and another kind to replace standard fuses in existing installations having standard fuse holders when a change in power supply has made higher short circuit capacity available than can safely be connected to a standard fuse.

The various specially constructed fuse holders of my' invention are all adapted to be modified in such a manner that they may be selectively installed to accommodate both standard fuses and the specially constructed fuses of my invention, or to accommodate only the specially constructed fuses of my invention. Thus it is not necessary to manufacture and stock two different kinds of fusible electrical devices, one with standard fuse holders and the other with soecially constructed fuse holders.

While the invention has been described as particularly useful to prevent installation of standard fuses when safety demands a fuse having high circuit interrupting capacity, it will be obvious that the invention is equally applicable to insure installation of fuses of proper ampere rating, or proper current limiting characteristics, etc., and to prevent installation of fuses which may be considered improper for any reason.

Accordingly it is an object of the invention to provide a novel construction for fuses with special characteristics and for fuse holders adapted to cooperate therewith, wherein the novelly constructed fuses will also fit in standard fuse holders but the novelly constructed fuse holders will not accommodate standard fuses.

A further object of the invention is to provide a novel fuse holder which can be selectively installed in one "ice manner to accommodate only novelly constructed fuses particularly adapted to cooperate therewith and in another manner to accommodate said novelly constructed fuses as well as standard fuses.

Another object of the invention is to provide novel construction of fuses and fuse holders having all the advantages hereinbefore set forth.

Other objects and advantages of the invention will hereinafter appear.

in the drawings:

FIGURE 1 is a side elevational view of a standard ferrule-type fuse holder holding a standard ferrule-type cartridge fuse;

lGURE 2 is a side elevational View, partly in section, of a special ferrule-type fuse holder constructed in accordance with the invention and holding a special ferruletype cartridge fuse constructed in accordance with the invention;

FlGURE 3 is a cross-sectional view taken along section line of FIGURE 2;

FIGURE 4- is a side elevational view of a modified form of the specially constructed fuse holder of FIG- URE 2;

FlGURE 5 is a side elevational view of a standard knife-blade type fuse holder holding a standard knifeblade type cartridge fuse;

l lGURE 6 is a side elevational view of a special knifeblade type fuse holder constructed in accordance with the invention and holding a special knife-blade type cartridge fuse constructed in accordance with the invention;

7 is a cross sectional View taken along section line 7 of FIGURE 6;

FIGURE 8 is a fragmentary side elevational view showing a modified form of the specially constructed fuse of FEGURE 6;

FIGURE 9 is a side elevational view of another standard knife-blade type fuse holder holding a standard knifeblade type cartridge fuse;

FEGURE 10 is a side elevational view of a modified form of special knife-blade type fuse holder constructed in accordance with the invention and holding a special knife-blade type cartridge fuse constructed in accordance with the invention;

PlGURE 11 is a cross sectional view taken along section line l111 of FIGURE 10;

FIGURE 12 is an end elevational view of a clamping member of one of the fuse clips of the standard knifeblade type fuse holder of FEGURE 5;

FIGURE 13 is a plan view of a portion of a mounting panel showing mounted thereon a standard ferrule-type fuse holder holding a standard ferrule type cartridge fuse and a special ferrule type fuse holder constructed in accordance with the invention and holding a special ferrule type cartridge fuse constructed in accordance with the invention; and

FIGURE 14 is a plan view of a portion of a mounting panel showing mounted thereon a standard knifeblade type fuse holder holding a standard knife-blade type cartridge fuse and a special knife-blade type fuse holder constructed in accordance with the invention and holding a special knife-blade type cartridge fuse constructed in accordance with the invention.

FIGURE 1 shows a standard fuse holder 19 holding a standard ferrule type cartridge fuse 15 comprising a hollow cylindrical insulating barrel 16 and electrically conductive hollow

cylindrical ferrules

17 and 18 closed at their outer ends. it will be understood that the fuse 15 contains a fusible element (not shown) extending betw en the

ferrules

17 and 18 within the barrel 16, and that all the other fuses shown and described herein contain fusible elements. The fuse holder 19 comprises a pair of identical electrically

conductive fuse clips

26 and 21 mounted in spaced-apart relationship on an insulating base member 22 which, for example, could be a separate member or part of a panelboard. The fuse clip 2t comprises a clamping member 23 having a pair of resilient curved arms 24 for engaging the ferrule of a cartridge fuse such as fuse and the arms are provided with a loading spring member 25 which serves to urge them together and to limit axial movement of the fuse. The clamping member 23 is provided with a threaded mounting hole 26 which registers with a mounting hole 27 in an electrically conductive terminal plate 28 having a wire connecting screw terminal 29 thereon. A mounting screw 30 extends through a mounting hole 31 in the base member 22 and through the mounting hole 27 in the terminal plate 23 and screws into the threaded mounting hole 26 in the clamping member 23 to secure the fuse clip 20' and the terminal plate 28 to each other and both to the base member 22.

The fuse clip 21 comprises a clamping member 32 having arms 33 and a loading spring member 34 and the clamping member is provided with a threaded mounting hole 35 which registers with a mounting hole 35 in a terminal plate 37 having a screw terminal 33 thereon. A screw 39 secures the fuse clip 21 and the terminal plate 37 to the base member 22. The arms 24 of the clamping member 23 and the arms 33 of the clamping member 32 are of the same shape as arms 62 of a clamping member 61 of FIGURE 3, to be hereinafter described.

FIGURE 2 shows a special ferrule-type cartridge fuse 40 constructed in accordance with the invention and mounted on a special fuse holder 41 constructed in accordance with the invention. The term special used in connection with a fuse or fuse holder means specially constructed in accordance with the invention. The special fuse 49 may for example comprise an insulating barrel 42 which is shorter than the barrel 16 of the standard fuse 15 shown in FIGURE 1 and is provided with electrically conductive ferrules 43 and 44 and with an additional ferrule 45 which is reversely disposed endto-end to the ferrule 44 and is electrically and mechanically attached thereto as by welding or soldering as at 46. The ferrule 45 forms a registry means or cylindrical extension on the end of the fuse 4t and is open at or has an opening in its outer end. The ferrules 44 and 45 could also be formed as a single tube with a barrier between the ends thereof. Other equivalent ways of constructing one end of the special fuse 40 will be apparent to those skilled in the art.

The special fuse holder 41 comprises a pair of

fuse clips

47 and 48 mounted on an insulating base member 49. The fuse clip 47 in FIGURE 2 is identical to the fuse clip 20 shown in FIGURE 1, and comprises a clamping member 50 having arms 51 and a loading spring member 52. The clamping member 50 is provided with a threaded mounting hole 53 which registers with a hole 54 in a terminal plate 55 having a screw terminal 56 thereon. A screw 57 secures the clamping member 50 and the terminal plate 55 to the base member 49. The fuse clip 48 shown in FIGS. 2 and 3 is like the fuse clip 21 shown in FIG. 1 in that it comprises a terminal plate 58, a screw terminal 59, a mounting screw 60, and a clamping member 61 having arms 62, but it differs therefrom in that a spring member 63 thereof is reversely dsposed and enlarged so as not to interfere with the insertion of the ferrule of a fuse, and the terminal plate 58 is longer. If preferred, the spring member 63 could be omitted. It is to be noted that the

clamping members

50 and 61 of the special fuse holder 41 in FIG. 2 are closer together than the

clamping members

23 and 32 of the fuse holder 19 in FIG. 1. In addition to the foregoing components, the fuse clip 48 includes an interference means which takes the form of a U-shaped rejection bracket 65 having a lower leg 66 provided with a threaded hole d7 which accommodates the mounting screw dtl which secures the bracket 65, the clamping member 61, and the terminal plate 53 to the base member 49. An upper leg or portion 68 of the interference means terminates adjacent the outer endof the clamping member 61 of the fuse clip 43 and is adapted to be accommodated by the cylindrical extension 45 on the special fuse 4h. The portion 68 is outside of the clamping member 61, or not within the space immediately between the arms 62.

From the foregoing description of FIGS. 1, 2, and 3 it is apparent that while the standard fuse 15 shown in FIG. 1 can be accommodated by the standard fuse holder 19 shown in FIG. 1, it cannot be accommodated by the special fuse holder 41 shown in FIG. 2 because the clamping members 5419 and 61 of of the fuse clips 47 and 43, respectivcly, of the latter are too close together and the portion 68 of the rejection bracket 65 interferes with insertion of the fuse into the clamping member 61. It is further apparent that the special fuse 40 shown in FTGS. 2 and 3,

which has substantially the same overall length as the standard fuse 15, can be accommodated by the special fuse holder 41 shown in FIG. 2 and by the standard fuse holder 19 shown in FIG. 1 since the ferrule 45 on the special fuse 40 would be accommodated by the clamping member 32 of the fuse clip 21 of the standard fuse holder 19.

FIG. 4 shows a special form of fuse holder 79 fabricated in two

separate sections

71 and 72 which can be selectively disposed on a mounting panel 73 in either of two positions relative to each other so as, first, to accommodate the standard fuse 15 shown in FIG. 1 or the special fuse 4-0 shown in FIG. 2, or second, to accommodate only the special fuse lll. The section 71 of the fuse holder 7% comprises an insulating base block 74 and a fuse clip 75 identical to the

clips

29 and 47 shown in FTGS. l and 2, respectively. The insulating base block 74 is provided with a mounting hole 76 for accommodating a mounting screw 77 receivable in a threaded mounting hole 78 in the mounting panel 73. The section 72 of the fuse holder comprises an insulating base block 79 and a fuse clip 8%) identical to the fuse clip 48 shown in FIGS. 2 and 3. The insulating base block 79 is provided with a mounting hole 81 for accommodating a mounting screw 32 receivable in either of two spaced-apart threaded mounting

holes

83 and 84 in the mounting panel 73. If the mounting hole 83 in the mounting panel 73 is employed, as shown in FIG. 4, the clamping members of the fuse clips and St) are spaced apart the same distance as the

corresponding clamping members

23 and 32 of FIG. 1 and either the standard fuse 15 shown in FIG. 1 or the special fuse 40 shown in FIGS. 2 and 3 may be inserted. However, if the mounting hole 84 in the mounting panel 73 is employed, it will be understood that the clamping members of the fuse clips 75 and 8%) will be spaced apart the same distance as the corresponding

clamping mem bers

50 and 61 of FIG. 2 and only the special fuse 49 shown in FIGS. 2 and 3 may be inserted. The mounting screw 82 may then be a one-way screw, or it may be inserted from the back of the mounting panel 73, if utmost safety is desired.

It is to be understood that the selective arrangement disclosed in connection with F G. 4 wherein ferrule type cartridge fuses and fuse holders therefor are employed can also be applied to the knife-blade type cartridge fuses and fuse holders therefor which ahe hereinafter described.

FIGS. 5, 6, 7, 8, and 12 illustrate another embodiment of the present invention. FIG. 5 shows a standard knifeblade type cartridge fuse comprising an insulating barrel 116 and electrically conductive knife-

blade terminals

117 and 118 mounted on a standard fuse holder 119. The fuse holder 119 comprises a pair of identical electrically fuse clips 12f) and 121 mounted in spaced-apart relationship on an insulating base member 122. The fuse clip 12% comprises an electrically conductive clamping member 123 having a pair of resilient straight arms 124, best seen in FIGURE 12, for engaging the knife-blade terminal of a cartridge fuse such as fuse 115. The clamping member 123 is provided with a mounting hole 125 which registers with a threaded mounting hole 126 in an electrically conductive terminal plate 127 having a screw terminal 128 thereon. A mounting screw 129 extends through a mounting hole 136 in the base member 122 and through the mounting hole 125 in the clamping member 123 and screws into the threaded mounting hole 126 in the terminal plate 127 to secure the fuse clip 12% to the base member. The fuse clip 121 is identical to fuse clip 12% and will not be separately described.

FIGURE 6 shows a special knife-blade type cartridge fuse 132 constructed in accordance with the invention and mounted on a special fuse holder 133 constructed in accordance with the invention. The special fuse 132 is identical in size and shape to the standard fuse 115 shown in FIGURE 5 except that the knife-blade terminal 134 thereof is provided with registry means in the form of a curved notch or cutout 135. If preferred, the special fuse 132 could be provided with a straight notch 136 as shown in FIGURE 8.

The special fuse holder 133 shown in FIGURE 6 is identical in all respects to the standard fuse holder 119 shown in FIGURE 5 except that the clamping member 137 of its fuse clip 138 is provided with an interference means which takes the form of a rivet or rejection pin 139, best seen in FIGURE 7, which extends through a pair of holes 1% and 141 in arms M2 and 1 33 thereof, respectively, and is adapted to accommodate the cutout 135 in the terminal 134 of the special fuse 132. If preferred, the holes 1 1i and 1 11 in the arms 142 and 143 could be threaded and instead of the pin 139, a bolt (not shown) could be employed.

From the foregoing description of FIGURES 5, 6, 7, 8, and 12 it is apparent that while the standard fuse 115 shown in FIGURE 5 can be accommodated by the standard fuse holder 11? shown in FIGURE 5, it cannot be accommodated by the special fuse holder 133 shown in FIG- URE 6 because the rejection pin 139 will interfere with insertion of the knife-blade terminal 118 into the clamping member 137. It is further apparent that the special fuse 132 shown in FIGURE 6, or that shown in FIGURE 8, can be accommodated by the standard fuse holder 119 of FIGURE 5, and it can also be accommodated by the special fuse holder 133 shown in FIGURE 6 merely by engaging the pin 139 in the notch 135 (or 136) in the knife-blade terminal 134 and pivoting the fuse into engagement with the clamping member of the other fuse clip 144 of the fuse holder 1133.

FIGURES 9, l0, and 11 depict another embodiment of the present invention. FIGURE 9 shows a standard knifeblade type cartridge fuse which may be identical to the standard fuse 115 of FIGURE 5, mounted on a standard fuse holder 151. The fuse holder 151 comprises a pair of identical electrically conductive fuse clips 152 and 153 mounted in spaced-apart relationship on an insulating base member 154. The fuse clip 152 comprises an electrically conductive clamping member 155 having a pair of bent-over resilient arms 156 for engaging the knife-blade terminal of a cartridge fuse such as fuse 15f therebetween. The arms 156 are shaped identically to

arms

167 and 163 of a clamping member 166 of FIGURE 11, to be hereinafter described. The clamping member 155 is provided with a mounting hole (not shown) which registers with a mounting hole (not shown) in a C-shaped loading spring (not shown) which grips the bent-over resilient arms 156 to insure that the latter grip the knifeblade terminal of a fuse properly. The loading spring may be identical to a loading spring 169 of FIGURE 11, to be hereinafter described. The mounting hole in the loading spring also registers with a threaded mounting hole (not shown) in an electrically conductive terminal late 157 having a screw terminal 158 thereon. A mounting screw 159 extends through a mounting hole (not shown) in the base member 154, through the mounting hole in the clamping member 155, through the mounting hole in the C-shaped loading spring, and screws into the threaded mounting hole in the terminal plate 157 to secure the fuse clip 152 to the base member 154. The fuse clip 153 is identical to fuse clip 152 and will not be separately described.

FIGURE 10 shows a special knife-blade type cartridge fuse 16f constructed in accordance with the invention and mounted on a special fuse holder 161. The special fuse 161i is identical in size and shape to the standard fuse 156 shown in FIGURE 9 except that the knife-blade terminal 162. thereof is shorter than the corresponding one on the standard fuse 150.

The special fuse holder 161 comprises a pair of electrically conductive fuse clips 163 and 164 mounted in spaced-apart relationship on an insulating base member 165. The fuse clip 164 comprises an electrically conductive clamping member 166 having a pair of bent-over

resilient arms

167 and 168 for engaging the knife-blade terminal of a cartridge fuse such as fuse 169 therebetween. The clamping member 166 is provided with a mounting hole (not shown) which registers with a mounting hole (not shown) in a C-shaped loading spring 169 which grips the bent-over ends of the resilient arms 167 and to insure that a knife-blade terminal will be gripped properly. The mounting hole in the loading spring 169 also registers with a threaded mounting hole (not shown) in an electrically conductive terminal plate 170 having a screw terminal 171 thereon. A mounting screw 172 extends through a mounting hole (not shown) in the base member 165, through the mounting hole in the clamping member 166, through the mounting hole in the loading spring 169, and screws into the threaded mounting hole in the terminal plate 17d to secure the fuse clip 164 to the base member 165.

The fuse clip 1.63 is identical with the fuse clip 164 as thus far described, and will not be separately described. The fuse clip 164 is additionally provided with an L-shaped interference member 173 having its short leg 1'74 secured to the bent-over arm 167 by a screw 175 and its long leg 176 depending between the

arms

167 and 168 adjacent the outer end of the clamping member 165. The screw 175 may be a one-way screw, or it may be otherwise locked in position, if utmost safety is desired.

From the foregoing description of FIGURES 9, 10, and 11 it is apparent that while the standard fuse 155 shown in FIGURE 9 can be accommodated by the standard fuse holder 151 shown in FIGURE 9, it cannot be accommodated by the special fuse holder 161 shown in FIGURE 10 because the interference member 173 interferes with the insertion of the knife hlade terminal of fuse 150 into the clamping member 166. It is further apparent that the special fuse 16f) shown in FIGURE 10 can be accommodated by the special fuse holder 161 shown in FIGURE 10 because of the shorter length of its knife-blade terminal 162 which does not interfere with the interference member 173 on the clamping member 166 of the fuse clip 164.

FIGURE 13 shows a portion of a mounting panel 130 having a standard ferrule-type fuse holder and fuse 181 and a special ferrule-type fuse holder and fuse 182 mounted thereon. The standard fuse holder and fuse 31 are like the fuse holder 16 and fuse 15 of FIGURE 1, and the special fuse holder and fuse 182 are like the fuse holder 41 and fuse 49 of FIGURE 2.

FIGURE 14 shows a portion of a mounting panel 183 having a standard knife-blade type fuse holder and fuse 184 and a special knife-blade type fuse holder and fuse 185 mounted thereon. The standard fuse holder and fuse 184 are like the fuse holder 1 19 and fuse 115 of FIGURE 5, or the like the fuse holder 151 and fuse 150 of FIGURE 9. The special fuse holder and fuse 185 are like the fuse 7" holder 133 and fuse 132 of FIGURE 6, or like the fuse holder 161 and fuse 160 of FIGURE 10.

By way of example, if a user of a mounting panel 130 has a supply of fuses .15 and a supply of fuses 40 on hand, he cannot inadvertently or intentionally create an unsafe condition by placing a standard fuse 15 in a special fuse holder 41 of the fuse holder and fuse 182.

Various modifications may be made in the structure disclosed without departing from the spirit and scope of the invention.

I claim:

1. The combination comprising a mounting panel, a first fuse clip, a second fuse clip, interference means disposed adjacent said second fuse clip, a first ferrule type cartridge fuse of predetermined length, and a second ferrule type cartridge fuse shorter than said predetermined length but having registry means on one end such that the total length of said second fuse and registry means taken together is substantially equal to said predetermined length, said fuse clips being mountable on said mounting panel selectively in two different relative positions with respect to each other in both of which relative positions said interference means is disposed on the opposite side of said second fuse clip from said first fuse clip, said fuse clips being disposed a first predetermined distance apart in a first of said relative positions and being disposed a second predetermined distance apart in a second of said relative positions, said second predetermined distance being greater than said first predetermined distance, said registry means being cooperable with said interference means and said second fuse being mountable in said fuse clip for clamping engagement thereby when said fuse clips are in said first relative position, said first fuse interfering with said interference means and being unmountable in said fuse clips when said fuse clips are in said first relative position, said first fuse clearing said interference means and being mountable in said fuse clips for clamping engagement thereby when said fuse clips are in said second relative position, and said second fuse being mountable in said fuse clips with said registry means clampingly engaged by said second fuse clip when said fuse clips are in said second relative position.

2. The combination comprising a mounting panel, a

first fuse clip mounted on said mounting panel, a second fuse clip mounted on said mounting panel, said fuse clips respectively being constructed and arranged to clampingly engage opposite end ferrules of a ferrule type cartridge fuse, interference means adjacent said second fuse clip on the opposite side thereof from said first fuse clip, said interference means including a projection having a fixed end portion and a free end portion, said free end portion of said projection being disposed closer than said fixed end portion to said second fuse clip, and a ferrule type cartridge fuse having first and second opposite end ferrules respectively clampingly engaged by said first and second fuse clips, said second end ferrule having a generally cylindrical extension thereon having an open outer end, and said free end portion of said interference means being received in said cylindrical extension on said second end ferrule of said ferrule type cartridge fuse.

References Cited by the Examiner UNITED STATES PATENTS 502,541 8/93 Thalacker 200-433 850,836 4/07 H-ornsby et a1 200119 1,067,568 7/ 1-3 Young 2001l3 1,093,607 4/14 Davis 200--l33 1,122,575 12/14 Cook et al 200133 1,227,753 5/17 Cole 200133 1,413,735 4/22 Hynes 200119 1,665,446 4/28 Conrad 339253 1,953,343 4/34 Frank 200133 1,953,807 4/34 Jackson et a1 339259 1,981,929 11/34 Starrett 317-116 2,086,727 7/37 Morris 200133 2,380,114 7/45 Kurillo 200--133 2,907,849 10/59 Kobryner 200119 2,943,295 6/ 60 Stewart 339-258 FOREIGN PATENTS 153,023 1/56 Sweden.

ROBERT K. SCI-IAEFER, Acting Primary Examiner.

MAX L. LEVY, BERNARD A. GILHEANY,

Examiners.

Claims

2. THE COMBINATION COMPRISING A MOUNTING PANEL, A FIRST FUSE CLIP MOUNTED ON SAID MOUNTING PANEL, A SECOND FUSE CLIP MOUNTED ON SAID MOUNTING PANEL, SAID FUSE CLIPS RESPECTIVELY BEING CONSTRUCTED AND ARRANGED TO CLAMPINGLY ENGAGE OPPOSITE END FERRULES OF A FERRULE TYPE CARTRIDGE FUSE, INTERFERENCE MEANS ADJACENT SAID SECOND FUSE CLIP ON THE OPPOSITE SIDE THEREOF FROM SAID FIRST FUSE CLIP, SAID INTERFERENCE MEANS INCLUDING A PROJECTION HAVING A FIXED END PORTION AND A FREE END PORTION, SAID FREE END PORTION OF SAID PROJECTION BEING DISPOSED CLOSER THAN SAID FIXED END PORTION TO SAID SECOND FUSE CLIP, AND A FERRULE TYPE CAR-