US484865A - Automatic cut-out - Google Patents

Description

(No Model.) 4 Sheets-Sheet 1. G. E. SANFORD. AUTOMATIC GUT-OUT.

No. 484,865. Patented Oct. 25, 1892.

(No Model.) 4 Sheets-Sheet 2. C. E. SANFORD.

AUTOMATIC GUT-OUT. No. 484,865. Patented Oct. 25,1892.

(No Model.) 4 Sheets-Sheet 3. C. E. SANFORD.

AUTOMATIC GUT-OUT. No. 484,865, Patented 001:1. 25; 1892.

(No Mudel.) t V 4Sheets-Sheet 4. C. E. SANFORD.

AUTOMATIC GUT-OUT.

No. 484,865. Patented Oct. 25, 1892.

UNTTED; STATES PATENT OFFicE.

} CHARLES E. SANFORD, OF BROOKLYN, NEW YORK.

AUTOMATIC CUT-OUT.

SPECIFICATION forming part of Letters Patent No. 484,865, dated October 25, 1892.

Application filed May 17, 1890. Serial No. 352.172- (No model.)

To aZZfwhom it may concern.-

Be it known that LOHARLEs E. SANFORD, of Brooklyn, New York, have invented certain Improvements in Self-Protecting Telephone and Telegraph Protectors, of which the following is a specification.

The improvements relate to a type of protectors for" telephone and telegraph instruments analogous to that shown and described in Letters Patent of the United States No. 336,040, dated February 9, 1886, in which a single armature is employed as a circuit-closer.

and a high-resistance electro-magnet is combined with a relatively-low resistance electromagnetfor thepurpose of increasing the sensitiveness with which the apparatus operates to close aishunt-circuit around the telephone or other instrument to be protected whenever the circuit becomes charged with a current of abnormal? strength. I.

The present invention consists in the combination of a series of three or more electromagnets the resistances of which diminish in a prescribed ratio-and which are each provided with an armature arranged to act as a circuit-closer for closing a branch circuit, by means of which abnormally-strongcurrents are not only shunted around the instrument to be protected; but the more delicate electromagnets of the sericsthat is to say, those whose coils are composed of the finer wireare securely guarded against the destructive efiects to which they would be subjected if momentarily exposed to an abnormally-strong current.

The mode of operation of the apparatus will be easily understood on reference to the accompanying drawings, illustrating simple forms of apparatus embodying the invention.

The drawings are as follows:

Figure 1 is a top view of the structure in which the electro-magnets are separated from each other and which includes a symbolic representation of the circuits and the instruments to be protected. Fig. 2 is an end elevation of the structure shown in Fig. 1. Fig. 3 is a front elevation of the same. Fig. 4 is a transverse vertical section taken through the plane indicated by the dotted line or soon Fig. 3. Fig. 5 is a front elevation exhibiting a modification in which the magnets are compactly grouped together, and Fig. 6 is an end circuit. The coil D of the electro-magnet D is composed of wire of prescribed fineness and of a sufficient number of convolutions to insure a sufficiently-energetic magnetization of its core D to enable the attractive force to overbalance the strength of the armature-- spring d and swing its armature 01' against its stop 01 and thereby close the branch c1rcuit d whenever the main circuit becomes charged with a current which in a prescribeddegree is in excess of the normal current employed to operate the telephone. The current is thus split, the greater portion flowing into the branch d and the smaller portion through the helix D of the first electro-magnet. The greater portion of the current is thus, by means of the branch d conducted to the ground without going through the'telephone B. If, however, there is a continued increase in the strength of the current in the main cir cuit, then before the current becomes strong enough to burn out the fine-wire coil of the magnet D it energizes the second magnet E sufficiently to overcome the retractile strength of the armature-spring e, and to thus move the armature 6' against the stop 6 and thereby close the branch circuit e which, by affording another path for the current, still further diminishes the quantity flowing through the fine-wire coil D. Again, when the current in the main circuit has increased in strength to a further prescribed degree the third electro-magnet, wound with a still coarser wire, is energized sufficiently to enable its attractive force to counterbalance the retractile spring f and move its armature f against the stop f,

and thereby close the third branch f by which another portion of the current is conducted to the ground without being required to flow through the coils of the magnets. It will of course be understood that a series of any desired number of electro-magnets may be thus arranged and operated; but it will usually be found that three are sufficient for ordinary purposes. For example, if it be assumed for the sake of illustration that the circuit is to be normally charged with a current of half an ampere then the first electro-magnet may be so adjusted that a current of, say, threefourths of an ampere will suffice to give it magnetic energy sufficient to overcome the retractile force of its armature-spring and enable it to close the branch circuit 01 Assumng that the wire of which the first armature is wound is to be guarded against a current of, say, one ampere, then the second electromagnet E will be so adjusted that a current of one ampere will enable it to attract its armature e and close the circuit e Again, assuming that the Wire composing the helix E of the second electro-magnet is large enough to carry with safety a current of notmore than ten amperes, then the third electro-niagnet F will be so adjusted that a current of ten amperes will give it sufficient magnetic energy to overcome the retractile strength of its armature-spring f and move its armature j against its stop, and thereby close the branch circuit f The Wire composing the helix F of the third electro-magnet is assumed to be sufficiently large to safely carry the heaviest current to which the apparatus will be exposed; but it will of course be seen that if desired there may be added to the series any additional number of electro-magnets, the coils of which may be composed of relativelylarger wires.

In order to secure a large contact area, the armature f has affixed to it the copper disk f, and the stop f upon which the periphery of the disk f is adapted to bear, is a copper plate electrically connected with the ground and projecting across the end of the electromagnet F, and perforated immediately opposite the core of the electro-magnet F.

As a measure of abundant caution, the main circuit may be provided with the ordinary fusible section II.

'What is claimed as the invention is 1. The herein-described self-protecting telephone and telegraph instrument protector, which consists of three or more electro-mag nets, the helices of which respectively vary in resistance in prescribed degrees and are connected in series in the main circuit, which includes the telephone or telegraph instrument to be protected, a number of normallyopen branch circuits to the ground or shunts around the telephone or other instrument to be protected, equaling the number of electromagnets employed, and a like number of armatures for respectively closing said branch or shunt circuits successively when the helices of the magnet become charged with abnormal currents of prescribed strength.

2. The electro-magnet F and the stop f the same consisting of a metallic plate electrically connected with the ground and projecting across the end of the electro-magnet F and having a perforation immediately opposite the core of the said electro-magnet, in combination with the armature f and the disk f carried upon said armature for closing the branch circuitf by the contact of its periphery with the face of the said stop f, as set forth.

CHARLES E. SANFORD.

Witnesses:

A. M. JONES, J. E. BURNS.

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