US1076754A - Safety appliance for electrical installations. - Google Patents

Description

l W.v F. FORCE.-

SAPETY APPLIANE POR ELECTRICAL INSTALLATIONS.

APPLIOATION IILIEDl JAN. 24, 1912.

ATORNEYS Patented Q01.. 28,1913.

protection.

Unirse sraras rarest carton.

"YIBZILIL'UVL F. FORCE, OF IFIiATBUSH, NEW' YORK, AESIGNG. Ol" NE-HALF 'E0 ERNEST LA .I-liM, Ol? BROOKLYN, NEW' FRK.

earner arriiianos ron atncfsarcet iissratnarrons.

Speccati'onof Letters Patent.

Application alec January ai, 191e. sei-iai No. avales,

To allicht/m i may concern.'

Be it lrnoivn that l, Trilplaat F. Foncia, a citizen of the United States, residing at Flatbush, Kings county, State of New York, have invented certain new and useful lmproveinents in Safety Appliances for Electrical Installations, of'which the following is a full, clear, and exact description. l

My invention relates to safety appliances for electrical installations. lilith thermal cut-outs, as at present made, Ain some instances, it is easy for an unauthorized person to substitute arcut-out of a large capacity for a cut-out vofa smaller capacity, thereby removing from the installation the desired It isfurther possible to alter the fusible member of the cut-out, Without danger of detection, by substituting` for a fuse strip of one capacity. a conductor of larger capacity or one which will not act properly as a fuse. It is further possible to connect the two terminals of an inclosed fuse by an external strip. which is a conductor which does not readily actas a fuse, or by means of a fuse strip of large capacity. It is further possible with some devices, such as those known `as Edison plugs, to insert a piece of metal in the socket, which vill connect the tivo line terminals, and thus coinplete the circuit independently of the fuse carrier. It. is further possible to easily alter the fuse socket of such devices so that an electrical connection will be made irrespective of the fuse strip carrier.

My invention has for its object to make it practically 'impossible to do any and all of these things.

My invention further hasffor its object to produce a device, in whichy connection cannot be made with the circuit at one end of an inclosed fuse unt-il after a good cornice-- tion has becnimade with the other terminal of the inclosed fuse.

`My invention further has for its object to provide a device in which the danger due to live conductors or contacts Vis practically eliminated.

My invention further has for its object to provide a support Which 'incloses the inclosed fuse so as to prevent danger if the' ininclosed` thermal cut-outs of any suitable closed fuse explodes so as to burst its casing.

The following is a ydescription of an enibodinient of my invention, reference being had A to the accompanying drawings, in which,l v

Figure l is a panel board having a series of appliances embodying my invention. Fig. 2 is a partial section onthe line fc--m Fig. i. F ig. 3 is a partial section on the line .Q/-a/ Fie l- .Referring more particularly to the drawings. l is'tlie base of a panel board having bus bars 2 22 2" connected to the main circuit. 1

3-3 are terminals of one branch circuit connected to said bus bars.

fat-4' are terminals of the secondbranch circuit of larger capacity connected to said bus bars.

Mounted upon the panel. board 'are fuse holders. each consistingr of a porcelainbasc 5 provided with a bore G extending partly therethrough, the inner ends 6 of the bores boing slightly smaller than the outer portions. niinals 3---3 are the same in all respects. The bases over the ends of the terminals 4 4 are the saine as each other in all respects but differ from the bases over the terniinals 3 3 as hereinafter pointed out. The pairs 'of similar bases are preferablv 'formed integral and are secured to the panel hoard by screws 32 and 42. The terminals 3-3 and 4-4 are provided at their ends with holes or sockets 7, those of the terminals' 3-8 being smaller than those of the The bases over the ends of the terlzatciitet Oct. 28, 1913.

terminals 4 4. These holes 7 are preferably y screw-threaded. They are each in line with 'he airis of the bore of the correspondingr base, Which bores at their inner ends are closed by closures 8 perforated with holes 9 in line with the holes 7, The bases are provided with vrecesses 10 on one side, through which pass conductors 11, secured to binding posts 12, and terminating in connecting rings 13, which rest upon Hanges formed on the bases at the outer en'ds of the bores. In case the holes 7 are screw-threaded, the inner surface of the-rings 13 are preferably not screw-threaded. i

14, 14 are inclosed fuses, by which l mean ing.

Thefuses of the proper @simcity for ther Abranch circuit fl,

4f have larger plugs 19 than the iinses of 'the proper capafrit,T for the ircnit 3, The projections of the larger size .fuses are bored out internallj7 at 2O to malte it impossible to machine a plus' down to the size ot a smaller i., beine* obvious that with this arrangement, 'the reducing` of the larger plug' to the size ori' the smaller plus$1 would cut anni@v the metal entireiv. The holes in the extensions raav be filled with some sott metal, as showin, to increase the conductiv-- ity. The outer end of the inclosed fuse is 'provided ivithfa erriile 21 havim;` a flange 22. 'il`his"liant{e is adapt d to engage the ring' 13 ivhen `the inolosed 'useis in place. ,lf the ferrule 21 and the ring 13 are not provid-ed With screw threads, or other means for holding the inclosed fuse in place, the projections 19 and the holes Y are provided with screvv threads -for that purpose, and the construction last referredl to, namely, the screw-threaded extension and hole, is'the preferable construction. The inse strip or member 15 Within the casing; 16 is connected to the plug' 17 and the urrule Q1', 'so as to form a y@goed electrical connection between them. 1l cap 23 made of insulation, such lglass or porcelain, is cemented or otherwise secured to the terrule 21 so that when the inclosed fuse is being put into place, it is unnecessary to touch any live contact. ller clearness the cap is omitted in Fig. 1.

The enlargement in the bore extends to ,slightly below the center of the inclosed fuse,

so, that if the inclosed fuse bursts there will be ample space for the gases to escape with ont bursting' the base, Theinner part 6 of the bore tits the inner end of 'the inelosed fuse closely so as-to prevent the insertion of any thin piece oi? metal, by which an unauthorized persen might attempt to bridge the two terminals of the inclosedfuse. The hole 9 through the inner end. 8 of 'the fuse support is of such sise as to just permit the passage of the projection 19 which engage@ the conductor 3 or 4f. The fuse 14 hasa smaller projection than the fuse 1li, which latter is .ot the larger capacity. The size ot the hole 9 at the inner end ot the bore tor the small capacity fuse will not permit the passage of the extension ol the larger capacity fuse, and. cannot be easily7 reamed out so as to permit that passage, smce'rcaming it out :z-.znid probably break the porcelain Levens@ base. it, therefore, not only prevents the insertion of a large capacity fuse, but prevents access to the end of the conductor 3 for the purpose of reamingout the hole therein, which would also be necessary it the larger capacity ruse was to 'he inserted in the circuit ot' smaller capacity. The construction has the. advantages above reiferred to,`

inasmuch as the inner end 48 of the base, which, except for the opening 9 therein, separates the inner terminals 3 or Il from the outer terminal 13, makes it difficult to connect the two line terminals, except by Substituting' some` device, which is especially,7 made to be substituted, and the terminals of -the inclosed fuse cannot be bridged because the plufrl? is an'internal plug, and the inner end of 'the bore G is ojtI such size as to prevent the insertion ot the inclosed fuse casing'it' a, bridging member has b v any means been secured to the outside thereof. Moreover, if it were attempted to connect a bridging member with the bottom ot the plug 17, it Would lift the flange 22 so that it would no longer make contact With the ring terminal 13. A conductor cannot be sif'itisfactorilji7 substituted for a blown fuse strip within the inclosed fuse casing, since the fuse strip does not penetrate the plug 17. For this reason, even if it were iossible to solder one end of a substitute conductor to the ferrule 22, it would be impossible to make a proper electrical connection between, the other end and the plug 17. The insulating cap 23, however, not only enablesI the use to be inserted without handling a live parl-,but in and of itself prevents the insertion in the fuse casingr of a conductor in lieu of proper fuse, by inc'losing the upper end or the ferrule 22.

The extension 19 makes engagement with the conductor4 3 or e, prior to the engagem ment of the flange 22 with the ring 13. Contact, therefore, is not made at the outer end of the inclosed fase until it is fully in place. The inclosing wall forming the bore 6 surrounds the inclosed fuse, and affords protection against lire in case the casing of the fuse bursts, and yet, on account or' its enlarged outer portion, permits the escape of gases due to the rupture of the fuse strip. rlhe inclosed fuses, having the proper sized extensions to engage the conductors 3 or 4i,

cannot be inserted into the casing so asvto complete the electrical circuit, unless they are of the proper length,- that is, a fuse which is too long for the intended service will not make electrical contact with the ring; 3 in a base intended for a shorter fuse. A -tuse intended for a short base will not malte electrical contact between the entension 19 and the conductor 3 or 4, it inserted in a base intended for a longer fuse. I pre 'fer lto make the projections 19 on all fuses screw-.threaded .in the .same direction, and

,to rely unen the differences in size et the projections in order to prevent .the exchange of inclosed fuses of the saine length, or of different capacities, since if rig-ht and left handed screws of the same size were used to distinguish between fuses or' different caacities, the thread on the extension belonging .to the Afuse of the larger ycapacity might' be re-cutso that the fuse could be used on a circuit where a fuse of a smaller ,capacity one to six amperes inclusive; those of a capacity carrying from seven to twelve amperes inclusive; those of a capacity carrying from thirteen-to twenty amperes inclusive; those of a capacity carryin from twentyone to thirty amperes inclusive. If the inclosed fuses of each group are constructed according to the above descri tion, and have their inner terminals provi ed with extenby those skilled in permits of various `sions of differentsizes, one size for each group, such a classification will be sufiicient or ordinary purposes.

The construction above described is the preferred form. It will be seen, however, the art, that my invention modications without departing from the s irit thereof, or the scope of the appended c aims.

' That I claim is:

1. In a device of the character described, the combination oa fuse support having a bore therein, a conductor constituting a line terminal having a socket concentric with said bore andlocated near one end thereof, said support having an insulating partition between the end of said bore and said conductor, and ,a perforation through said partition in line with said socket, a. second line terminal located at the other end of said bore, and an inclosed fuse consisting of an insulating casing having at one end a met-allic plug provided with an extension adapted to pass through said hole and engage said socket, and terminal adapted to engage said second line terminal, and a -fuse strip inclosed within said casing and connected to said fuse terminal and plug, said bore fitting a part of 'Said insulating casing closely.

2. In a device of the character described, the combination of a fuse support'having a bore therein, a conductor 'constituting a line having at the other end a ruseA terminal having a socket concentric with said bore and located near one endthereof,

said support haring an insulating pantition between theend oi said bore and Said con- -duetor'and a perforation. through said vpaitition in line with said socket, -a second vline terminal located at the other end of said i bore, and an inclosed fuse consisting of an insulating casing having .at one end a inetal- 4 lic plug provided with an extension adapte .to pass through said hole and engage said socket, and at the other end a fuse terminal adapted to engage said line terminal, said second external line terminal having a contact surface lying in aplane at right angles to the axis of said bore, and said outer fuse terminal having a contact surface extending at right angles to the axis of said fuse and adapted to engage said first mentioned contact surface, part of said bore iitting said insulating casing closely.

3. In a device of the character described,

the combination of a fuse support having a bore therein, a conductor constituting a line terminal having a socket concentric withl said bore and located near one end thereof, said support having an insulating partition between the end of said bore and said conductor and a perforation through said partition in line with said socket, a second line terminal-.located at the other end of said bore and having a contact surface at slibstantially right angles to said bore, and an inclosed fuse having a casingwithin one end of which is a metallic plug having an extension adapted to pass through said hole and engage said socket and at the other end of which is a terminal adapted to engage said surface of said-second line terminahsaid socket and extension having engaging screwthreads. v l

4f. In a device of the character described, the combination of a fuse casing, a metallic plug in one end thereof having an external projection, a errule on the other end thereof, and a fuse strip connecting said plug and said ferrule, said errule having a lateral projection forming a contact surface at right angles to the axis of said fuse.

5.' In a device or" the 'character described,

of insulation secured to saidferrule abovel` said lateral projection.

G. In a device of the character described, the combination of a base having a bore, enlarged near its outer end, a conductor having a-socket adjacent tothe inner end of said bore, a line terminal adjacent to the ico! iicl

plug and oher en@ of sa bow an insulating inner end of Sai@ f from fine sm'uc@ of the 0u 5 of im@ havl'l'g; a 31 said Socke@ mi fo 'an engag mmfl off.

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