US1824415A - Safety fuse device - Google Patents

Description

Sept. 22, 1931. J. STONE 1,824,415

SAFETY FUSE DEVICE Filed Sept. 9, 1929 JESSE S1035; I N VEN TOR.

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A TTORNEX Patented Sept. 22, 1931 UNITED STATES PATENT ori-ICE JESSE s'roNE, Yor PITTSBURGH, PENNSYLVANIA SAFETY FUSE DEvIcE .Applicationfled September 9, 1929. Serial No. 391,450.

the improvements which will be herein more 1U fully described may be yused with the ordinary fuse blocks now in use, while at the same time the fuse plugs now in use may not be used with any fuse blocks to which my improvements have been applied. In order to use'any fuse block having my inventionadded thereto, a special type of fuse plug is required-,'the nature of Vwhich will also be fully described in this specifica- -c-tion. The adaptability of myinvention for use without changing of arts, in connection with the ordinary type ofpfuseblocks in common use, will readily be understood from the description, and it will be at once seen that this feature constitutes ajvery desirablev one,

in my invention.

Two important features of the present in- Vention are the following, to wit, the modification of the bottom end of an ordinary 4F In thedrawings forming part of the present specification, l y

Figure 1 is a sectional view of my invention mounted -in a fuse block, and taken on line 1-1 of Figure 2. 50

Figure 2 is a plan View ofjthefuse block fuse plug,b the addition of a contact pin shown in Figure 1, the fuse plug and the Spe cial washer, 'or adapter being omitted for f clearness of illustration.

Figure 3 is a vertical partial section of the base of the fuse plug, and the adapter with associated parts.

Figure 4 is a top plan view of the fuse plug.

Figure 5 is a bottom view of the fuse plug.

Figure 6 is a plan View' of the special washer or adapter.

Figure 7 is a side view of Figure 6.

Figure 8 is a plan View of a locking spring ring used in connection with the adapter.

Figure 9 is a side view of the ring shown in Figure 8. e

In the drawings, the numeral 1, indicates a porcelain base, called the fuse block, of the form shown, provided with the usual necessary parts, such as the ingoing or feeder connection 2, and the outgoing branch circuit connection 3, the cup-shaped recess 4, with a metal ferrule 5 seated therein. The connection 2, leads by means of the bent plate 6 to the contact pin 7, shown clearly in Figure 1. f

The connection 3 is provided with a yoke 8, which is accommodated within the ferrule 5, and lies on the bottom 9 thereof. Above the yoke is an insulating thin washer 10, and a metal holding washer 11, and it is seen that the contact screw 7 passes through the cluster of parts just named, and down through the porcelain fuse yblock to the bent plate 6,'and is secured thereto, in the usual fashion. It will be noted the head 12 of the contact screw 7 is iattened somewhat, so that itseats nicely in the bottom recess 13 of the special micarta washer 14, see Figure 3.

The special washer, 14, or adapter ismade preferably of a hard, non-conductive, material such as compounded substances like micarta, which is composed of mica and other substances, commonly used in the trade. The purpose of requiring substantially hard material, will be more fully described below.

The cross-sectional shape or form of the adapter 14 is shown in Figure 3, and a plan view in Figure 6, in which it is seen that a concentric recess 15 is formed in the top of same, and a perforation 16 passes through the center, adapted to receive the fuse plug Vcontact pin 17. VOn the bottom Vof the wire in a compressed-position within the` periphery of the adapter, Vas shown in Figure 7. It will be seenV that while the spring .wire 19` is in 'compressed position, that the adapter can be inserted freely within the ferrule l5,Y and placed at the bottom thereof,

v on top of the head 12, of the contact screw 7,

with the former in the recess 13. Vhen the adapter is in this position the pin 2O is withdrawn, and the wire 19'springs outward, and locks itself in the grooves 23 of the ferrule 5, and the adapter then cannot be removed without destroying ferrule 5. The purpose of this is to enable theordinary ferrule of theV fuse block to be used with my `inventiomwithout anychanges being made. It is evident that this is a very importantfeature of the device, in that the present fuse blocks can be used without changes in their construction. Y

The fuse plug base, whichis newly formed in' the present invention, consists of the following. VThe portion of the fuse' plug 24, which is above the corrugated pro3ecting disc 25, is substantially the same as in common use, `except that the length of the plug is shortened. Mounted on the plug 24, is the fuse plug disc 25, which is formed preferably of the same material as the adapter, to wit, of a hard, insulating pressed substance, or com-v pound, which'has been made under hydraulic.r

or other great pressure. On the face-.of the disc 25, is mounted a concentric proJecting ringl 26, preferably made integral therewith and-also formed'complementary inshape with the recess 15 of the adapter before described, so it is evidentithe fuse plug base fits snugly intol the upper face of the adapter, and 'the I contact pin passesthrough the center perforation 16 yof the latter and makes contact with the top 12 of the contact screw 7, when the fuse plug 24 is screwed home7 in the threads of the ferrule-5. 4The contact pin may be mounted in any suitable rigid manner to the upper portion of the fuse plug 24, andthe `latter has the usual fusible element 27 within.

it for carrying the current from the cont-act pin-to the fuse 28, which in turn leads same to the metal screw threadscovering the plugrat' l 30, which in turn contact the threads 'of the This pinis only for a temporary Apin 17 will not, due to the thickness of the wire ferrule 5. From ferrule 5 it reaches the yoke 8 and the branch circuit connection 3.

From what has been said it is seen that electric current comes in through the feederconnection 2, passes through bent plate 6, into contact screw 7. Then to the contact pin 17, and through the parts just described above to the branch circuit connection 3.

Vx.lVith reference to the surreptitious use of the device, it is quite evident that coins cannot be used in any manner to form a connection electrically between the head 12 of the contactscrew 7, and walls of the ferrule 5, which is necessary in order to close the circuit from connections 2 to 3. Y 1 Y A i' v Should a piece of wire be wrapped around the contact pin 17 of the fuse plug, insuchva manner as to extend diametrically across the' base of the fuse plug,'toma'kea contact vwith the ferrule' 5, 'and the` plug then screwed home, it will -be foundthat ifthe wire is heavy enough to'resist the mutilating elfe-ct of the complement-ary corrugatedv parts of the plug and adapter, the lower end of the contact reach the head 12 of the contact screw, and the circuit will not be closed Iftinfoil, or v'very light wire is laid from ythe head 12 of the contact screw, to ferrule, turning effect of the plug as it is screwed to its seat, and the shearing effect of thecomplementary corrugations of the plug and adapter, will shear and mutilate the wire or tinfoil completely. 'If the wire or tinfoil is fine, or thin enoughto conform to the shape vof the complementary corrug-ations of the plug and adapter, it will be partially sheared, and so mutilated, that it will not have al current carrying capacity of over the fifteen amperes, the usual safe carryl ing capacity of the electrical system, and in this case will not injure thesame.

I claim:

v1. In a safety fuse device, a fuse block having a feeder connection, and a branch circuit connection, a ferrule mounted in the block, an adapter having a perforated center, a concentric recess formed in the upper faceof the adapter, and va peripheral recess formed in the adapter, a spring locking wire adapted'to fit in the peripheral recess, and lock the adapter within the ferrule, a fuse plug having a centrally disposed contact pin'therein, a fuse A plug'disc having a concentric projecting ring thereon formed complementary to the concentric adapter recess, a Contact screw mounted in the fuse block, means connecting n the contact screwl with the feeder connection, and means connecting. the Ycontact pin with the branch circuit connection;

2. In a safety fuse device, an adapter hav'- T adapter, a` spring ring mounted. in the Vpe-Z.

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ripheral groove, and means for holding the spring ring within the peripheral limits of the adapter.

3. In a safety fuse device, an adapter halving a central perforation therein, a concentric recess in its upper surface, a recess in its bottom face, a peripheral groove formed on the outer Walls of the ada ter, a spring ring mounted in the groove, a use plug having a cent-ral contact in, adapted to pass through the central per oration of the adapter, and a concentric projecting ring on the bottom of the fuse lug formed complementary to the concentrlc recess of the adapter.

4. In a safety fuse device, a ferrule, having a number of screw threads formed therein, an adapter having a peripheral groove and a pair of alined holes therethrough, a

split spring ring having tapered overlap- Y ping ends, and a pair of alineable holes therethrough mounted in the groove, and holding and releasing means comprising a holding pin adapted to pass through the holes in the adapter and split ring for holding the spring ring Within the periphery7 of the adapter while the same is being mounted in the ferrule, and for releasing the ends of said ring when the latter is in desired position Within the ferrule.

5. In a safety fuse device, a fuse block having incoming and out-going electrical circuit connections, a contact screw having connections With the incoming electric circuit connection, an adapter having a central perforation therethrough, a concentric recess in the upper face of the adapter, a recess in the adapter for accommodating the head of the contact screw, a ferrule on the use block having threads formed therein, a fuse plug having a contact pin mounted therein, a disc on the base of the fuse plug having a concentric projection thereon, formed complementary to the concentric recess of the adapter, for permitting the contact pin to form an electrical connection with the cont-act screw, means for locking the adapter in the ferrule grooves, and means connecting the contact pin with the out-going circuit connection.

6. In a safety fuse device, a split spring ring, having tapered ends, adapted to slide upon each other, and having erforations in said ends adapted to be in a ignment when the spring is in a contracted position, and a holding pin adapted to pass through the perforations, and hold the spring in contracted position.

7. In a safety fuse device, an adapter, having a peripheral recess formed therein, and a pair of perforations yin alignment with each other, a split spring ring, having a pair of perforations therein which can be aligned with each other and the perforations in the adapter when the spring ring is in a contracted position, and a pin adapted to pass

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