US1353123A - Cartridge-fuse - Google Patents

Description

L. 'F. KRIES. CARTRIDGE FUSE. APPLICATION FILED AUG. I6, 1918.

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LAWRENCE F. KRIES, OF BALTIMORE, MARYLAND, ASSIGNOR T0 CHARLES MORGAI'T MARSHALL, TRUSTEE, OF BALT IMOBE, MARYLAND.

CARTRIDGE-FUSE.

Specification of Letters Patent. Patented Sept. 14, 1920.

Application filed August 16, 1918. Serial No. 250,186.

To all whom it may concern.

Be it known that I, LAWRENCE F. Kniss. a citizen of the United States, residing at Baltimore, State of Maryland, have invented certain new and useful Improvements in Cartridge-F uses, of which the following is a specification.

This invention relates to thermal cut-outs for electric circuits, and more particularly to cut-outs of the cartridge fuse type.

It has been found in practice that in many cases where ordinary fuses are emwill often replace such a fuse by a fuse of too great a capacity or-even by a piece of wire, either to avoid the necessity of replacing burned out fuses or else for the purpose of obtaining a greater current than the circuit was designed to carry.

In order to more effectually limit the carrying capacity of a circuit and prevent re-fusing in an improper manner, the object of the present invention is to provide a cut-out device in the form of a cartridge fuse containing two separate fusible elements, one of which is accessible and can be renewed in the ordinary way, and the other of which is inaccessible or non-replaceable without destroying the cut-out. This accessible or non-accessible fusible element has a carrying capacity greater than the ordinary or replaceable element, but small enough to limit the current in the circuit to a safe figure.

In order that the invention may be readily understood, reference is had to the accompanying drawing forming a part of this specification and in which,

Figure 1 is a longitudinal section of a cartridge fuse embodying the principles of my invention;

Fig. 2 is a similar view taken on a plane at an angle of ninety degrees to that of Fig. 1, and

Fig. 3 is a transverse section on the line 3-4-3 of Fig. 1, looking in the direction of the arrow.

Referring now to the drawings in detail, my improved cartridge fuse comprises two separate sections 1 and 2 preferably separa bly united as by means of screw threads 3. The section or compartment 1 is closedat its ends by means of a disk 4, held in position by a screw-cap 6. having a flange 5. in order to prevent rotation of the disk 4 it is provided with portions adapted to interlock with notches 7 formed in the end of the casing 1.

Extending through the disk 4: is the usual or any suitable blade 8 constituting one terminal of the cut-out, and adapted to be received between spring clips, in the well known manner. To the inner end of the blade 8 ,is secured a bar of insulting material 9 carrying at its other end a metal 'clip 10 and between the clip 10 and the blade 8 extends the ordinary replaceable fuse 11, secured by means of screws 12. Other methods of supporting this fuse may he employed without departing from the spirit of the invention.

The other section 2 of the casing carries at its inner end a spring-clip 13 adapted to receive the clip 10 above described. This clip 13 is carried by a disk or partition wall 14 which is permanently secured in the end of the section 2 in any suitable way, and

held in position by ineansof an annular flange or shoulder 15. A nonreplaceable fuse 17 is secured at one end to the clip 13 as by means of a screw 16 and its other end is carried through an opening in a metal cap 19 which is secured to the casing 2. This cap 19 is permanently attached to the casing as by means of crimping, as indicated at 19. The end of the fuse 17, after passing through the cap 19 is cut off and may then be secured to the cap by fusing the end with a soldering iron or the like, so as to form a head or bead 18, as clearly shown in the drawing. A blade 20 is secured to the cap 19 in any suitable way, and constitutes the other terminal of the cutout.

It will be understood that the parts 1, 2, 4 and H are formed of any suitable insulating material such as hard fiber, or the like.

From the above description it will be obvious that by unscrewing the cap (3, the disk 4 and the attached blade 8, bar 9 and clip 10 may be withdrawn from the casing 1 so as to afford access to the fuse 11 for inspection or renewal. It will also be seen. that the fuse 17 is entirely concealed within the permanentlyclosed compartment 2, so

should be separated by unscrewing at the point 3. The fuse 17 is of greater carrying I capacity than the fuse 11, but is still small enough to blow with a current which the circuit can carry safely. If, therefore, an unscrupulous or ignorant person should undertake to replace the fuse 11' with a larger one or with a? piece of wire, it Would still be impossible for him to draw from the mains current in excess of that which the fuse 17 will carry, which fuse, therefore, serves to determine the maximumcurrent Which'the cut-out will stand and to limit such current to a safe figure.

It will be seen that my improved device, being in the natureof a cartridge fuse, is simple in construction and cheap to manufacture, and it is thought that its many advantages will be readily appreciated by those skilled in such matters.

If desired, the head 14 may be made of brittle material, or material which cannot be readily bored through, so that a wire or heavy fuse cannot be passed through the heads 19 and 14, when the part 1 is removed, and soldered or otherwise connected to the part 13, outside the head 14. If a fuse were so connected it would be concealed when the casing is assembled.

l/Vhat I claim is:

' 1. A cartridge fuse comprising an elongated casing divided by a transverse partition into two compartments, a fuse in each compartment, said fuses being of different carrying capacities and connected in series,

a portion of the casing forming one compartment being readily removable to afiord access to the fuse in that compartment, and the compartment containing the other fuse being sealed against opening except by destroying the casing.

2.'A cartridge fuse comprlsln'g an elongated casing divided by a transverse part1- tion into two compartments, a fuse in each compartment being sealed against opening except by destroying the casing.

3. A cartridge fuse comprising a casing having a contact terminal at each end thereof, said casin being divided into two compartments, a use in each compartment connected with its respective contact terminal, said fuses being of different carrying capacities and connected in series, the compartment containing one fuse being sealed against opening except by destroying the casing, its associated contact terminal and an adjacen't portion of the casing being readily separable as a Whole from the sealed compartment, to afford access to said second mentioned fuse.

In testimony whereof I affix my signature.

LAWRENCE F. KRIES.

and the second fuse, together with

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