US1788768A - Renewable electric fuse - Google Patents

Description

Jan. 13, 1931. v F. c. LA MAR I 1,

RENEWABLE ELECTRIC FUSE Filed Jan. 5, 1927 Mill-"wi l 1 nvmvron ayg aw he ATTORNEY U N j PATENT oFF cs rRANKcLa Man, or 'rrr rsnunon. rnnnsrnvlmin; Assrenon pro GREAT wns'rnnn ruse COMPANY, FPITTSBURGH-1,.PENNSYLVANIA, A conrona'rron or DELAWARE RE E ABLE nnn'o'rnrc rusE Application filed January 5, 1927. Serial No. 159,079., V

More particularly invention relatesfto:

ferrule-type fuses.

In electricfuses when the fusible element or reload is fused or burns out gases are 6 generated in considerable volume and at h gh temperatures and such gases carryin "suspension particles of: the fused metal. 4

nowincommon use is the tendency toward a' 10' concentrated escapeiof. thegasesaxially of the fuse, frequently resulting in welding. the parts of the;mechanismftogethereither by fusion or by thedeposit of themetallic particles. .Thus'the cap'may be fixed'to the i ferrule or theanchoringdisk maybefixed toleither or both, so as to be removable,.if at all, after a great deal. of .trouble 1 or the extremity of the fusibleelement may be welded to the anchoring disk or ferrule to both. i Y

20,. Escape of thegasesformedby fusion of the fusible elementmust, of course, be provided for to prevent-rupture of-the fuse which would prevent its reuse, but a concentrated escape must be, avoided :toyprevent the objectionable occurrences above mentioned.

My object therefore isto soiimprovethe constructionof renewable ferrule fuses theta restricted and :Widely distributed escape isv provided-for the gases, and thelmaterialdes .0 positof' the metal particles on the parts in movable relation is avoided.) 7 l 7 i 1 Thus I provide means, whereby afrestricted escapefor a portion of the gases is provided around the perimeter of thewasher which 7 between the cap and therferrule.

anchors the end of the fusible element and -I also provide means for baflling'a portion of the gases before they leave ,the ferrul eto cause the deposit of the metallic particles be- 14 fore they reach the pa-rtsin movable relation.

Other novel features of construction, and also of arrangement; of parts, will appear from the followingdescription.-

, Inthe accompanying drawings, wherein I have 'illustratedthe best embodiment of the principles of my invention now known tome, Fig. l is an elevation of a renewableferrule fuse partially broken away in longitudinal section to show the internal-parts; Fig. 2 is a similar view. but turnedninety degrees from 1;:Fig. 3 is an enlarged diametric section of one of the ferrules, its anchoring disk andcap, the ferrule being slightly modifled in construction from that shown in Figs.

1 and 2; Fig. 4 is a perspective of the anchoring disk; Fig.5 isaview s'imilarto Fig. 3but i showing a modificationwherein the bafile is TA faultof the-typesof renewable fuses.

a separate element from the ferrule-and Fig. Q

'6 is an elevation of thebafileshown in Fig. 5. 1 Referring first to Figs. 1 and 2, l-repreeach end of the 'shelll is fixed a metal, usually brass, ferrule 3. 9 The ends of the shell 2 are preferably provided with notches 2a to prevent a sealingcontact between the end of the shell and the ferrule." The inner end of theiferrule' is provided with internal threads which screw onto the external threads of the end of the shell 1. The outer end of the ferrule 3 is of reduced external diameter, thus forming an intermediate circumferential shoulder 4. if I Theouter end ofthe ferrule is provided with exterior threads 5' upon" which are screwed the interior threads 6 ofthe metal 8 cap '7which is preferably alsoof brass. At

either? end of the threaded portion 5'ofthe ferrule 3 is a plane annular surface of "the 1 and 2 said shoulder or bafiie 9 is disposed in a plane at right angles to' the axis of the shell and -ferrule, whi1e in Fig. .3 said shoulder. .or baffle is frusto-conical'in shape BX-.

tending inwardly of the shell .1.

I The boreof theferrule outwardly from the shoulder is ofprogressivelyincreasing diameter forthe purpose "of giving so depth of the threads-which surfaces form 1 with the skirt'of thefcap annular chambers '8 at the extremitiesrof the threadedengageclearance for the angularity of the fusible element 2 and to better distribute the gases which may pass outwardly through the throat 10.

At the outer end the bore of the ferrule 3 is countersunk-to form a disk-seatwhose inner end is the annular shoulder 11 and its side the annular wall 12.

13 is the disk which is employed to anchor the end of the fusible elementQ, the disk be ingprovided withan eccentrically positioned slot 14 through which theiextremity of the fusible element is inserted,said extremity being then bent-down flat against the exterior surface of the disk, as shown. In

assembling the fuse,- the disks are positioned.

with-their slots disposedat opposite sides of theaxial line of the fuse, thus causingthe' angularity-in'the disposal of the fusible element-shown in the drawings.

The disk 13 is of proper, diameter to fit looselylin its seat and is set outwardly in the same byvmeans of its struck-out toes 15 which rest on the shoulder 11. Thus there is provided a restricted escape for the: gases around the perimeter of the disk 13 and between'it and the ferrule.

.The .disk preferably protrudes slightly from the end of the ferrule and when the cap 7 is'screwed into place, it clamps the bentover extremity of the fusible'element betweenit and the disk: and also clamps the.

disk to "the ferrule. The end'of the cap 7 is spaced away from the end of the ferrule. The skirt of the cap 7is shortenough to inslurezla space between it and the ferrule shoulcer It is evident that in case of a burning-out disk and the cap. Furthermore a portion ofthe gases will be trapped by said baffle andwill be diverted and caused to find a restricted: escape betweenthe threads of the shell and the ferrule. T

Thexremainderiof the gases, passing outwardly through the throat 10 will finda distributed escape around i the. perimeter of the disk 13 and will then escape through the chambers 8 and between the ferrule 3 and the skirt of the cap 7 between the threadsof the same.

It'is thus evident that there can be no concentrated escape ofthe gases in such volume as to weld together parts in movable relation nor to causedanger of fire. At the same timesufiicient of the metal particles are divertedifrom passing through the throat 10 to prevent such welding action through the deposit of such particles. Again, the escape of the gases is so fully provided for that no rupturing of the fuse is possible.

In Figs. 5 and 6 I show the baffle formed as a separate element 16 formed with a per imetral lip 17 which is clamped between the end of the shell 1 and an internal shoulder 18 of the ferrule, while the body of the element is of frusto-conical form extending inwardly ofth'e shell 1'. In'this case the outer bore'of the' ferrule may be cylindrical instead of conical.

This modified form is less expensive than that. shown-inthe preceding views of the drawings, and thus may be regarded as preferable.

What I desire to claim is 1. In a renewable electric fuse, the combination of a shell of insulating material, a ferrulermounted on the end 0fv the shell, an anchoring disk. bearing against the end of the ferrule, the disk being spaced from the end of the ferrule to provide for the escape of gases between the ferrule and the disk, a fusible element in the shell and having its end anchored to the'disk, and a cap screwed onto the ferrule and holding the disk in position.

2. In a renewable electric fuse, the combination of a shell of insulating material, a ferrule mounted on the end of the shell, the bore of the ferrule being provided with a seat at'its outer end, a diskmounted in said seat, means for spacing the body of the disk out of contact With'the ferrule to provide for the escape of gases around the disk, a fusible element in the shell and anchored to the disk, and a cap screwed onto the ferrule and holding thedisk in position.

3. In a renewable electric fuse, the combination of a shell of insulating material, a ferrule permanently mounted'on the end of the shell and provided with an exteriorly threaded portion, an anchoring disk bearing against the outer end of the ferrule, the ferrule having an inwardly contracting central opening through which the fusible element extends, a fusible element in the shell having its end anchored to the disk, and a threaded cap screwed onto the threaded portion of shell and provided with an exteriorly threaded portion, an anchoring disk bearing against the outer end of the ferrule, the ferrule having an inwardly contracting central opening through which the fusible element extends, a fusible element in the shell having its end anchored to the disk, and a threaded cap screwed ontothe threaded portion of the ferrule, and a baflie in saidierrule arranged to divert a portion of the gases of fusion and cause them to escape between the portions of the fel ule and the cap which are in threaded en agement.

igned at Tucson, Arizona, this 24th day of December, 1926.

FRANK 0. LA MAR.

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