US1396731A - Cartridge-fuse - Google Patents

Description

R. C. COLE.

`CARTRIDGE FUSE.

APPLICATION FILED 1^N.24.192o.

'1,396,731 y Patented Nov. 15, 1921.

vwawtoz UNITED STATES PATENT OFFCE..

ROBERT C. COLE, OF HARTFORD, CONNECTICUT, ASSIGNOR TO THE JOHNS -PRATT CARTRIDGE-FUSE.

To @ZZ whom t may concern Be it known that l, ROBERT C. COLE, citizen of the United States, residing at Hartford,y in the county of Hartford and State of Connecticut, have invented a new and useful Improvement in Cartridge-Fuses, of which the following is a specification.

This invention relates to the construction of non-renewable cartridge fuses of the knife blade type.

The object of the invention is to provide a casing for a fuse of this class comprising parts which are simple to make and easy to put together, and which when once assembled cannot be taken apart or entered without special tools and `the destruction of or irreparable damage to essential elements.

This object is attained by locking the knife blades with key plates so shaped that when ittedftogether they close the endsof the tube, and which have lugs that slide into and lit undercut mortises in the ends of the tubes, and holding the key plates in place by the caps which engage with the edges of the lugs so that the caps cannot be removed after once being set without destruction or damage.

'Figure l of the accompanying drawings shows a side view of a knife blade fuse constructed according to this invention with one half cut in central section. Fig. 2 shows an edge view with one of the caps broken away. Fig. 3 shows a section of the tubular casing. Fig. 4 shows a. transverse section on the pla-ne indicated by the dotted line 4 4 on Fig. l. Fig. 5 shows a face view of one of the lock plates. Fig. 6 shows an edge view of the lock plate. Fig. 7 shows a face view of one of the caps. Fig. 8 shows a section of the cap.

The body of the casing consists of a tube l of fiber or other suitable insulating material. In each end of the tube diametrically opposite each other two dove-tail or undercut mortises 2 are punched or otherwise formed. The terminal blades 3 are formed of copper in the usual manner and are connected inside of the casing by any type of fusible link 4. On each blade just inside of the end of the tube a plate 5 is secured in such manner as to provide recesses 6 at the end of the tube between the inner edges of the wider part of the blade and the plate. These recesses could be, of course, made any desirable depth by simply cutting away Specification lof Letters Patent.

Patented Nov. 15, i321.

Application filed January 24, 1920. serial No. 353,752.

more or less of the edges of the wider sections of the blades. Each end of the tube is closed by a pair of key plates 7, each plate being substantially semi-circular and having a slot 8 that tits the blade and a dove-tail lug 9 designed to enter adove-tail mortise in the kend of the tube. T hese key plates are thrust together-on the blades from opposite sides over the ends of the tubes, and when each pair is completely together and the ends of the tube are closed thereby the dovetail lugs lie in the dove-tail mortises in the tube so that the keyV plates cannot move lengthwise of the tube. After these parts are in position the caps 10 with slots 11 that just iit the blades are slipped over the blades and onto the endsof the tube over the key plates. When in place the caps hold the key plates from moving transversely and unlocking the blades. After the caps have been put in place their inner edges may be spun down over the ends of the key plate lugs or the caps may be provided with internal shoulders l2 at their inner edges and the key plates so .formed that when assembled the lugs may project beyond the surface of the tube, then when the caps are slipped on, the lugs will yield until after the caps have reached their vclosing position, at which time the lugs will be free to spring outward slightly and engage the shoulders around the inner edges of the caps and thus prevent .the caps from withdrawal.

lVith this construction the caps hold the key plates from radial displacement and cover the joints between the key plates, and the key plates with their lugs entering the dove-tail mortises in the tube prevent the blades from rotating and from moving longitudinally inward or outward of the tube. .lt is preferred to make the key plates of very hard metal so that it will be difficult for anyone to drill a hole through them for the purpose of inserting a conducting wire. This construction is very easy to assemble and yet it is very diflicult to take apart, or to restore it after the fuse link is once blown without visible indication of the fact that the casing has been tampered with. The casing may or may not be filled with'the usual condensing and absorbing materials.

The invention claimed is l. A cartridge fuse comprising a tubular insulating casing having undercut mortises in ends, Contact terminals extending lio through the ends of the casing, a fusible link connecting the terminals Within the' casing, key plates engaging the terminals and having lugs itting the mortises in the'ends of the easing, and caps thrust upon the ends of the casing over the key plates and held against removal thereby.

2. A cartridge fuse comprising at-ubular insulating casing having undercut mortises in its ends, contact terminals extending throughthe ends of the casing, a Vfusible link connecting the terminals Within the casing, key plates engaging the terminals and having lugs fitting the mortises in the ends of the casing, and caps thrust upon the ends of the casing overY thkey plates and holding the plates against transverse displacement, saidcaps having their inner edges extending diametrically inward over the inner ends ot. the key plate lugs and held on the casing thereby.

V3. A cartridgejfuse comprising a tubular insulating casinghaving undercut mortises in its ends, contact terminals extending through the ends of the casing, a fusible link connecting the terminals within the casing,

key plates engaging the terminals and having lugs fitting the mortises in the ends of the casing, and caps thrust upon the endsof the casing over the key plates and holding them against removaland being held against removal thereby. Y

4. A cartridge fuse comprising a tubular insulating casing having dove-tail mortises in .itsV ends, Contact terminal blades extend- Aing through the ends of the casing, key

plates engaging the terminal blades and having dove-tail lugs 'fitting the mortises in the ends of the casing, and caps having slots fitting the terminal blades slipped longitudinally upon the ends of the casing and holding the key plate lugs in the mortises in the tube.

5. A cartridge fuse comprising'a tubular insulating casing having undercut mortises in itsl ends, contact bladesvvith recesses in their edges extending through the ends of the casing, key plates fitting the recessed seetions of the blades and having lugs ittingk the mortises in the ends of the casing, and

capshaving slots iitting the terminal bladesl slipped longitudinally upon the ends of the casing over the key plates and holding the plates Vagainst transverse displacement and held from longitudinal displacement thereby.

6. A cartridge fuse' comprising a tubular insulating casing having undercut irmortises in its ends, contact blades extending through the ends of the casing, anchor plates fastened on the blades Within the casing, key plates engaging the blades outside of said anchor plates and closing the ends of the casing, said plates having lugs fitting the mortises in the ends of the casing, and caps thrust upon the ends of the casing and formed inward over the'key plate lugs.

7. cartridge fuse comprising a tubular insulatingV casing having undercut mortises the ends of the casing, anchor plates fastened on the blades Within the casing, semicircular lkey plates ittedtogether and closing the ends of the casing about the blades outside of said anchor plates, the joints between said key plates being covered within by said anchor plates, lugs extending at substantially right angles from the keyv plates and Vittingthe mortises in the ends of the casing, and caps having slots tting the blades thrust'v longitudinally upon the ends of the casing over the key plates andholding the key plates against ktransverse displacement.

. in its ends, contact blades extending through n 8. A cartridge fuse comprising a tubular i thereby from `movement longitudinally of the casing and in engagement with the blade and 'therebyholding' the vblade from movement longitudinally ofthe casing, and a cap located on the endofthe casing over the key plates and holdingthem in' place and held against removal thereby.

nosniar o. conn.

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