US1545767A

US1545767A - Electric fuse

Info

Publication number: US1545767A
Application number: US361318A
Authority: US
Inventors: Wilford J Hawkins
Original assignee: Individual
Current assignee: Individual
Priority date: 1920-02-25
Filing date: 1920-02-25
Publication date: 1925-07-14
Anticipated expiration: 1942-07-14

Description

Patentecl July 14,` 1925.

UNITED STATES 'WILFOBD J. HAWKIN'S, OF IEONTCLAIR NEW JERSEY.

ELECTRIC FUSE.

Application filed February 25, 1920. Serial No. &361,318.

To all whom it may concem: p

Be it known that I, WILFORD J. HAwKINs, a citizen of the United States, residing at Montclair, in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in Electric Fuses; and I do hereby declare the following to be a full, clear, and exact description of the inventon, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to electric fuses and is directed to the provision of a fuse of an improved construction which is very effective in suppressing the are formed when the fusible link is burned out, in which the channel for the reception of the fusible link is of the smallest cross-section permissible, in which the fuse body is of great strength and which may be manufactured at low cost.

In the attainment of the foregoing objects I employ a fuse body made of a moldable insulating material possessing great strength, such, :Eor instance, as bakelite, condensite or other similar material. This fuse body is preferably molded to the form of a cylinder having an axial passage therethrough which is of substantially the same cross-sectional shape as the fusible link. In this way a fuse body is produced which is of such great strength as to practicall eliminate the danger of breakageof the ody by the explosion which occurs when the fusible link is burned out. Furtherrnore, the small size of the opening through the fuse body for the link removes the danger that an operator will employ two links together and thereby increase the carrying capacity of the fuse to such extent as to make it useless as a protective device. i

If desirecl, in order to simplifythe work of molding the fuse body, the latter may be formed in two parts each substantially semieircular in cross-section and each having half of the groove for the fuse link formed therein. When this is done I prefer to provide coacting ribs and grooves upon the abutting surfaces of the two parts of the fuse body so that a tortuous path is provided froni the interior to the exterior of the fuse body thereby restricting the freedom of flow from the interior to the eXterior of the fuse of gases developed when the link is burned out.

The pre ferred embodiment of the invention is illustratedin the drawings annexed hereto in which Fig. 1 is a central longitudinal section of the fuse; Fig. 2 is a transverse section on line 2-2 of Fig. 1; Fig. 3 is a view of a form of fuse' link which may be employed and Figs. tto 10 inclusive are transverse sectional views corresponding to Fig. 2 and illustrating modified forms of the fuse body which may be employed.

Referring to these drawings, 11 indicates a fuse body made of moldable insulating material such as bakelite or condensite. It is of cylindrical form With threads upon its ends and with a central passage through it for the reception of the fusible link 12. This central passage is of the same cross-sectional shape as the link 12 and is of substantially the same size as the link. It approximates the size of the link so closely that it is impossible to insert two links in the passage and thereby increase the carrying Capacity of the fuse without rupture of the link.

On the ends of the fuse body are end caps to which the ends of the link are electrically connected. These

end caps

13 and 14 are interiorly threaded to coact with the threads upon the ends of the body 11. One end 15 of the link 12 is bent at a right angle to extend along the end of the body 11 and when the end cap 14 is tightened up on the threaded end of the body 11, the end 15 of the link is gripped between the body 11 and the end of the end cap 14, thus making good electrical connection between the end cap 1 1 and the end 15 of the link.

At the other end of the fuse 'the link is similarly gripped by the end cap 13 but at this 'end a Washer 16 is provided. This Washer is in the form of a disc with a notch cut in its periphery and the end of the link 12 is bent along the face of the body 11, then through the notch in the washer 16 and then along the face of the Washer. This Construction is such that by tightening np the end cap 18 the end of the link 12 is gripped between the Washer 16 and the end of the end cap 13 and a portion of the end of the link 12 is eXposed through an opening 17 in the end cap 13 so that the rating of the fuse stamped upon the end of the link 'may be read throu h the opening 17.

If desira le, the fuse link 12-may have a thin coating of asbestos 18 applied thereto by means oi waterglass or other suitable cementso as to prevent scorching or carbonizing the walls of the passage for the link through 'the non-Contacting fse body 11 lOU In Fgs. 1 and 2 the .fuse body 11 is shown asintegral. If desired, however, especially for the purpose of reducing the manufacturing cost, the fuse body may be formed in two parts each of more or less semi-circular cross-section. In' Fig. 4 the fuse body is shown as formed of two parts, the division between the two parts being transverse to the plane of the opening for the fuse link.

In Fig. 5 the construction is the same except that the division is in the plane of the opening for thelink. In Figs. 6 to '10 inclusive constructions are shown corresponding to Figs. 4 and 5 except that ribs 19 and grooves are provided upon the abutting faces of the two, parts of' the fuse body. 'The ribs and grooves ma'y be rounded as shown in Figs. 7 and 8 or square as shown in Fig. 9 or dovetailed as shown in Fig. 10. All of these constructions provided for a tortuous path from the interior to. the exterior of the fuse body, thereby reducing the possibility that hot gases or flame developed when the fusible link is burned out may find their way to the exterior of the fuse body.

` All of the constructions illustratd and described above are characterized by marked simplicity ofdesign and great strength to resist internal pressure. This great strength is secured by reason of the use of a fuse body which is of considerable thickness Compared to its exterior diameter and the formation of the fuse body from condensite or other similar moldable insulating material which is nonhygroscopic and therefore does not vary in physical dimensione with variations in the humidity of the atmosphere.

By making the passage through the fuse body for the reception of the fuse of small size, the thickness of the wall of the fuse body is increased for greater strength, there is less space for the storage of gases developed when-the fusible element burns out and two fusible elements cannot be used together to increase the carrying capacity of the fuse. Also, it will be noted that the rating of the -fuse link may be read through the opening in the end cap without removing any'part of the fuse structure and a new fuse link may be inserted in place of one which has been burned out without the employment of any special tool such as a screw driver.

I claim: 4

In a fuse a. body of molded insulating ma terial comprisin two symmetrical parts formed to provi e a passage between the parts and having cooperatng tongue and groove means, at opposite sides of the-passage to hold the parts in assembled relation, a fusible link extending through the passage and metal caps threadedly engaging the ends of the body and adapted to contact with the ends of the fuse.

In testimony whereof I afl ix my signature. i

WILFORD J. HAWKIN S.