US1866491A - Self-indicating refillable electric cartridge fuse - Google Patents

Description

July 5, 1932. 3, SQHMID 1,366,491

SELF INDICATING REFILLABLE ELECTRIC CARTRIDGE FUSE Filed Aug. 29, 1929 a2 i 2/ 9 m m. 7 26 y; E 35 25 25 V 2% 7.44. 2/ /9 20 f .3. 2 d m1! 33 /5 A? 25 LI /.6 W M /2 23 30 X i9( 7 /2 25 I JZ L gig.

255M415 w fiww INVENTOR ATTORNEY WESS S BY Patented July 7 5, 1932 UNITED STATES PAT NT OFFICE r ANcIs CHARLES SCHMID, OF THE UNITED STATES NAVY sELE-mnIcATm EEF LLABLE ELECTRIC CARTRIDGE FUSE Application flled migust 29.1929. Serial No. 389,259.

when such fuses havebeen of'the self indicat ing type it has been necessary to use particular care in installing the fuseso that the indicator will be visibleat the front of the panel board.

Certain types of fuses have beenheretofore I features wherebythe electrician could determine the particular fuse that has blown, but such fuses have been more expensive than those of the blind type, and when blown have included no provision for being re- I filled, thefuse being. discarded and replaced with anew one at additional expense. To

solder the broken ends of a'fusible link has heretofore been impossible with certain types of fuses, and impracticablewith others by reason of the time required, for suchpurpose.

Heretofore, when fusesfhave included'provision'for replacement of the fusible element they have always been of the blind type, having the disadvantage above referred to. The primary object of my invention is to enable the fuseto be constructed so that it will'be self indicating andalsoso' that the fusible link element will be replaceable with a new fusible element whenever it has been destroyed, so that the same cart-ridgecan be used over'and overagain, and also to enable the fuse to be constructed so'that when the fuse has blown, the indicator or flag will. be visible in any position of the fuse, whereby the installer can quickly positionthe fuse between the contacts without taking time to find the indicator side and position said side at the'front. l

A further object is to provide a fusible element or link which can be kept on hand in quantities for replacement purposes. Still further objects are to simplify and improve the construction of electric cartridge fuses, to reduce the cost ofmanufacture of the fuse as a whole, as well as the cost of replacement, and to provide an electric cartridge fuse which will be self indicating and refillable and as well, quick acting and arcless.

Other objects and advantages of the invention will be hereinafter specifically pointed out, orwill become apparent, as thespecification proceeds. i

-VVith the above indicated objects in view, the invention resides in certain novel 'constructions and combinations and arrangement of parts, clearly described in the following specification and fully illustrated in the accompanying drawing, which shows an embodiment of the invention as at present preferred. f

In the drawing:

Fig. l is a perspective view of the fuse bodyi Fig. 2 is a. longitudinal sectionalview 30 through the fuse,-showing the parts in operating position. i 1

' Fig; 3 is a partial sectional view taken on the lne 3-3 of Fig. 2. v

.Fig. 4 is a partial longitudinal sectional view similar to Fig. 2, showing the parts in the position assumed when the fusible element has blown and the indicator or flag hence caused to assume) its indicating posi- 9 tion. 0

Fig. 5 is a perspective view of the refiller plate.

Fig. 6 is a perspective view of the renewable fusible link.

The electriccartridge fuse 10 in this ing5 stance includes a cylindrical shell or body 11, preferably formed of insulating material, and having a homer chamber 12. A cylindrical head 13 is secured at one end of the shell. "This head 13 has asmaller diameter screw-threaded portion 14 and is provided with an axial aperture 15 communicating with the inner chamber 12. The interior walls of the head 13 are inclined at opposite sides, as seen at 16 and 17 so that they converge from the end of chamber 12 toward the axial aperture 15.

At the opposite end of the shell 11' a rim 18 is provided; and a cylindrical housing 19, having a chamber 20, is adapted to be removably secured to the end rim 18 by means of one or more bayonet joints as seen at 21, though any other approved form of securing means may be used for the latter. The housing 19 and rim 18 are formed of conducting material such as brass or copper.

Within the housing chamber 20 I provide an indicator device which in this instance is in the form of a disk 21 including an annular flange and having an attaching device, such as a hook 22, secured at the central portion of the disk and arranged to extend in the direction of the shell chamber 12. Resilient means, such for instance as a compressible spring 23, are provided between the indicator disk 21 and the rim 18 for the shell or body 11.

A suitable fusible element is adapted to be secured to the indicator disk 21, and in this instance I provide an elongated link 24, formed of suitable fusible material. This link 24 has a reduced portion or neck 25 about midway of its length, though the latter may be provided at any desired point, and securing means in the form of an aperture 26 at one of its ends. The hook 22 is adapted to be passed through the aperture 26 to hold this end of the fuse in position.

The fuse link 24 being attached at one of its ends as described, the housing 19 is placed over the end of the shell 11 and secured in place at the bayonet joint 21, the free end of the fuse link extending through the chamber 12 and aperture 15. During this passage the fuse link is guided into and past the aperture 15 by the inclined wall portions 16 and 17. The fuse link is drawn outward, compressing the spring 23 to which the opposite end of the fuse link is secured, and bringing the spring 23 into contact'with themetallic rim 18, to cooperate with the hook 22 in establishing electrical connection between the housing 19 and fusible link 24. The spring 23 may be compressed part way, as seen in Fig. 2 and electrical connection will still exist because the base of the spring engages the rim 18. The outer, free end of the fusible link is adapted to be held in place at the outer end of the head 13 by aremovable securing or refiller plate 28 havingan-inwardly extending lug 29 adapted to engage the link 24 with a wedging action in the axial aperture 15. The free end 30 of the fusible link is then bent over the outer surface of the refiller plate 28 as seen in Fig. 3, after which a cylindrical cap 31 is screwed on to the threaded portion 14 of the head 13 so that the inner face of the cap securely clamps the end of the fusible link against the refiller plate. In this position of the parts, electrical connection is established between the fusible link, the cap 31 and head 13, and the fuse is ready for use. The cap 31 preferably has a slot 32 for use in applying a screw driver to tighten the cap 31.

Overload of electric current in the circuit will cause the fusible link to melt at its weakest point, 25, and this parting of the link will cause the spring 23 to be released, breaking the electric circuit. Expansion of this spring forces the indicator disk or flag 21 from its normally concealed position to its outer limit against the outer end of the housing chamber 20, as seen at 33 in Fig. 4. A plurality of window openings 34, 35 and 36 are provided through the side walls of the housing 19 so that when the circuit has been broken and the indicator or flag forced outward as just described, the flange of the flag, which is indicated by the reference numeral 27 will be visible through the windows 34, 35 and 36. These windows are located at spaced points around the wall of the housing 19 so that at least one of the windows will be located toward the front regardless of the axial position of the fuse when placed in position between its respective contacts on the panel board.

To refill the cartridge and enable the same to be used over again, the cap 31, refiller plate 28, and housing 19 are disassembled, as will be readily understood, and the separated ends of the fusible link withdrawn from the shell 11. The end of the fusible link connected to the hook 22 is then withdrawn and a new fusible link of the same construction, as seen in Fig. 6, is attached to the hook 22 and the parts are reassembled as hereinabove described.

It will be understood that the fusible link 24 may be constructed of wire or other equivalents as well as of thin leaf metal as shown herein.

My present invention provides a fuse which is self-indicating, refillable, and as well, areless, because the construction enables the broken ends of the fusible link to be instantly separated through the action of the compressible spring. The fuse thus presents in a simplified unit, the combined advantages of practically all types of electric cartridge fuses. It can be rated for any voltage or amperage; and it operates and indicates instantly. When it is desired to renew the fusible element the aid of a screw driver is all that is required. The refills can be furnished in quantities for each fuse, at a trifling expense, so that fuses once purchased can be maintained in operating condition by being refilled whenever necessary at an expense that is practically insignificant. The present imuse and economy in cost and upkeep.

The hereinbefore" described construction admits of considerable modification without departing from the. invention; therefore, I

do not wish to be limited to the'precise arrangements shown and steps described, which are, as aforesaid, by way of illustration mere 1y. In other words, the scope of protection contemplated is to be taken solely from the appended claims, interpreted as broadly as is consistent with the prior art.

What I claim as new, is: I

1. An electric cartridge fuse comprising a shell, a head secured atone end of said shell, said head. having an, axialaperture, a housing at the opposite end of said fuse, an indicator disk positioned in said housing, resilient means interposed betweensaid'indicator and the end ofsaid shell, a replaceable fusible link having one of its endsattached to said indicator, the opposite end of said link adapted to extend through said axial aperture at the opposite end of the shell, means to hold the end of said fusible link in wedging engagementat said axial aperture, a screw cap on said cyindrical head, said cylindrical housing having a plurality of spaced window openings at the outer sides thereof, whereby the breaking of said fusible link is adapted to'release said resilient means and project said indicator outward toward the outer end of said housing and render I said indicator disk visible through said window openings.

2. An electric cartridge fuse comprising a shell. a head securedat one end of said shell, said head having an axial aperture, the interior walls of said head having inclined sides converging toward said axial aperture,ahousing removably mounted at the opposite end of said fuse, an indicator'disk positioned in said housing, a compressible spring between said indicator and the endof said shell, an elongated replaceable fusible link having one threaded on said cylindrical head to secure the extended end of said fusible link in clamping engagement, said cylindrical housing having a plurality of spaced Window openings at the outer sides thereof, whereby the breaking of said fusible link is adapted to release said spring and project said indicator outward toward the outer end of said housing and render the edge of said indicator disk visible through said window openings.

3. In an electric cartridge fuse, a hollow cylindrical body, a rim surrounding one end of said body, a housing for said end and being provided with bayonet slots, pins extending from said rim and receiving said bayonet slots for securing the housing to said body, said housing having openings arranged in annular formation about the same, a spring pressed indicator in the form of a disk including an annular flange adapted to show through the openings and mounted for slidable engagement with the housing, a head for the opposite end of said body, a replaceable fusible element disposed in said body, a hook secured to the disk and detachably receiving one end of said fusible element for connecting the latter to the disk, a cap for said head, means received by said head and cooperating with said cap for securing the opposite end of the fusible element to said head, and said fusible element normally holding said disk with its annular flange out of registration with the openings.

In testimony whereof I have aflixed my signature.

FRANCIS CHARLES SCHMID.

of its ends removably attached to said indi-v

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