US2507940A - Magnetic switch - Google Patents

Description

May 16, 1950 G. T. SOUTHGATE MAGNETIC SWITCH Filed Feb. 12, 1943 INVENTOR. GEORGE T500 THGATE /5M1? M v Ma ATTORMQXS Patented May 16, 1950 "UN?! ISTATES PATENT OFFICE MAGNETICSWITGH :George '-T. .Southgate, Forest. Hills,. N. .Y. May 0. southgate,eadministratrix of said George T. .Southgataideceased,assignor to May'C. Southgate :ApfilioationSFebruary 12, 1943,:Serial: N 0.475567 grentof-a voltage different from the voltage of -.the available'sourceof supply. For example; the plate circuit of a receiver, transmitter, or elecatronicsystem-mayrequire-a comparativelyhigh qdirect current "voltage whereas the only available asou-rce abattery vof lowvoltage.

One obj ect' of the invention is a novel "and improved vibrator structure for use'in converting siaidirect current source of'one'volta'ge to a source f another voltage.

A further object =-of -the invention'is such "a system embodying-a novel and improved vibrator or-interrupterunit whichris characterized by its improved performance and dependability in 'operation.

.--A' further object of the invention'is'a. novel and improved electromagnetic. interrupter unit.

@Further "objects of 'the invention will herein- ..after I appear.

-;.-For -.a better :understanding tof the invention reference may be had to the: accompanying drawsings :wherein:

Fig. 1 is a schematic'view of a direct current conversion system 'emhodyingithe invention;

:Fig. 2 is a vertical: sectional view through an interrupter unit embodying certain features of -the invention;

1Fig..- 3 iis'a sectional' view alongthe' line 33 'of iFigu' :Fig. 4 is an elevational view of the interrupter -atrightanglestothat of Figi'z with certain parts =removed and "'Fig.;5:-is asectionalview of a modified form of .interrupter.

Referring to the drawings?an available source on-direct currentas-for example a'low voltage battery,-is=indicated at B. The invention resides -in the vibratory meansuisedin the system for #stepping up the :voltage of the direct current .isource 'Bito ?a .voltage suchas that required for instance to feed "the plate circuits of a "conven- .tional radio receiver embodying electronic devices, or any other device requiring a higher direct -'current voltage than that available at the source The means andsystemfor converting the voltage of the direct current source B to'the voltage *oftheoutput-circuitcomprises an input switch "'S ran interrupter orvibrator' unit A,:'a transformer "iT;-an output'full wave rectifier 'orpair Iof .rectifiers Brand .of filter-F inthe circuit between the rectifiers and .the output circuit.

The vibrating unit A includes an electromag- .netic. coil P which .isconnected in series with the primary am the transformer, The resistance of ,thecoillPis very highas compared with the resistance of theprimary 2 of the transformer and the .variationscf .thecurrent flow inprimary 2 .are effected by rapidly closing and opening a :shortcircuit. about the coil P. This rapid make- .andebreak .meanscomprises .a. pair of stationary -.contacts..3.and a-corresponding pair of movable contacts l.

In addition .to .its. function as an electromagnetic coil for operating the armature,-more specifically described-below andcarrying the movablecontacts 4, .the coil P functions asthe primary.ofatransformer in which the secondary of .thistransformerisindicated at Q. The secondary .Qpfthetransformer has many more turns ,thanthecoilP, and. accordingly the voltage generated across the stationary contactst upon the interruption and closure .of the circuit is multipliedacross thesecondar-yQ of the transformer.

,An electrostatic. condenser Cis .connectedacross .the secondaryQ and .a resistance D. of small Wattage is .connectedacrossthe condenser.

The .unit.-A is more specifically illustrated in ..Eigs..2-4. ..It comprises .a base-.5, preferably of .some plastic material, asfor example phenolic resin, .uponwhichare mounted the coils P and ..Q, the coil .P .beingdisposed within the coil Q, .the twobeing insulated from each other in any suitable manner, as for example-by means of aninsulating sleeve.6therebetween. A disk 'I of insulating material is disposed on the top of the plete the circuits between the bottom of thering IL! .and the side .strips 9. The strips 9.project slightly above the insulating disk l forcooperation with the ends H of the armature II, the

projectingparts being designated l2. Theparts chanical contact between them. The coil P is insulated from the split ring ID by means of an insulating ring or sleeve I3 and the coil Q is insulated from the strips 9 by means of a ring or cylinder Id of insulating material.

The armature II is carried on the upper end of a helical spring I5, this spring I5 being of any suitable metal, as for example steel. In the particular embodiment shown, this spring is anchored to the base by being screwed onto a stud I6 at or integral with the base. The spring wire is of the required diameter and the coil of the required coil diameter and of the required length to give the stiffness desired or computed for the requirements of the particular use. The spring is guided within the member ID and the latter is shown as having a slightly outwardly flared opening at the top. The armature II may be fastened to the spring I5 in any suitable manner, but I have found a particularly advantageous method of fastening to consist of first forming an aperture in the armature I I at approximately its central point with the walls of the aperture helically inclined to the surfaces of the armature, and then inserting the end of the wire through this opening and screwing the spring therethrough for a distance of one or more turns.

The arms 4' carrying the movable contacts 4 are integrally formed with the armature II, and both of them together form a moline cross with the longer arms constituting the magnetic armature I I' and the shorter arm 4' forming a current bridge carrying the movable contacts. This moline cross member may be formed of sheet metal and readily stamped on a quantity production basis. By interrupting the circuit at two points, the contact openings are thus doubled, halving per gap the voltage and energy of any possible sparks. Molybdenum is preferred for the contact metal because of its sufiicient refractoriness, better mechanical properties and greater availability than tungsten.

The vibratory actuation of the interrupter is effected on the short-out principle; the closing of the contacts shunting the main-circuit current from the actuative coil P (of relatively few turns), and thus releasing the armature. With the coil thus again energized by the opening of the contacts, the cycle is repeated at the natural frequency of the elastic system. The preferred frequency is 100 to 300 cycles per second.

In addition to the vibrator circuit, the converter system includes the other circuit described above including the transformer secondary Q, the condenser C and the resistor D. This circuit is for the purpose of suppressing sparks at the contacts 3. 4 and for dissipating the energy thereof, thereby relieving the coils of this function. The coils of the unit A are, as indicated, the windings of a closely coupled transformer, stepping up the voltage at the contacts 3 and 4 and on the coil P to the much higher voltage at the terminals of the secondary Q. The effectiveness of the condenser C is thereby increased nearly as the square of the voltage ratio. A smaller condenser may thereby be used. It is preferably of the A.C. dry electrolytic type for sturdiness, capacity, and high voltage adaptability.

In order to protect the vibrating mechanism against dust, changes in atmospheric conditions, etc., it is housed in a housing I! as of glass. In the particular embodiment shown, this housing I! is of cylindrical shape and is screw-threadedly attached to an annular flange 5' formed on the base 5. The mechanism may thus be effectively insulated against moisture and the effects of large temperature changes are minimized. The elastic element or spring I5, if made of steel, may be slightly affected by large temperature changes but the change in the modulus of elasticity resulting from wide changes in temperature are insufficient in the ordinary case to impair unduly the efficiency of the system. If desired, the elastic member may be made of a metal which has a substantially constant modulus of elasticity over large temperature ranges, such for example as the alloys known in the trade as Monel metal and Elinvar.

In the particular embodiment of the invention shown, the condenser C and the resistor D are positioned outside of the housing II. The resistor D dissipates the energy which is stored in the condenser C and accordingly the temperature problem is minimized since the coils are not required. to dissipate this energy in the closed chamber H.

In the embodiment of Fig. 5 (drawn on a larger scale) the armature II is of shorter length than that of the armature in Fig. 2 and accordingly the inertia effects of the vibrating armature are less. This shorter length of armature I is compensated for by bending the strips 9 over at right angles at the top to form inwardly extending parts 20 so as to bring the upwardly projecting parts I2 of the armature circuit closely adjacent the ends II of the armature. The tube or ring I0 is provided with the slit or slot 2| to form it into a split ring similarly to the ring III of Fig. 2, the slot there not being shown.

In this embodiment the spring I5 is screwed through the moline cross comprising the armature II and the arms 4 of the contacts so as to have a part I5 projecting above the armature II and this part I5 of several turns of the spring is utilized for screwing thereupon and tightly against the armature I I, a lock nut 22, the latter being illustrated as screwed tightly against the metal of the armature II. A strong cement may be used to seal the lock nut.

The vibrator illustrated with the converter system above described may be used in any application where the voltage of a direct current source needs to be changed for use at a different voltage. In the particular embodiment shown, the system is designed for stepping up the voltage from a battery B to the voltage used in an electronic circuit, but the invention has other uses, as for example, systems employed in industrial control and operation. The parts of the system are mainly of noncritical materials and are particularly adapted to precision manufacture. The parts are rugged, durable and capable of withstanding rough usage.

The input switch S is indicated as of a rotary snap type that reverses the direction of the current through the vibrator at successive resumptions of service. This is an added safety feature in the event that the special cooperating spark preventing and dissipation circuit comprising the coil Q, condenser C and resistor D should for any reason become defective, in that the successive switch reversals would prevent cup and cone formation on the contacts.

The rectifying circuit includes as indicated above the electronic rectifiers R and the filter unit F. This circuit also includes a condenser C2 connected across the secondary of the trans former T. Its function is to supply the Wattless current for magnetizing the transformer core 5. and thus to relieve the primary circuit of that function.

As described above, the available source of direct current B in the particular embodiment shown is of a low voltage battery source. The system is adapted to the stepping up of the voltage of the battery B to any reasonable value within limits, as for example when the output circuit supplies the plate circuit of communication apparatus or equipment wherein the voltage desired may be from 100 to 500' volts.

I claim:

1. A vibratory means comprising an electromagnetic coil, a vibrating contact actuated by said coil, said contact being carried by an armature which is mounted upon and supported solely by a coil spring, said coil sprin being fixed at one end and fastened to said armature at the other end by passing one or more turns of the wire of the spring through an inclined opening formed in the armature.

2. A vibratory means comprising an electromagnetic coil, a magnetic circuit for said coil comprisingla centrally disposed member of magnetizable material, members of magnetizable material disposed on one end of said coil and on the sides thereof, and a movable armature at the other end bridging the side and central members of said 'magnetic circuit, said armature being mounted solely upon the end of a coil spring and being moved bodily against the tension thereof by the energization of the coil, and contacts carried by said armature, said armature being formed in the shape of a cross with one pair of arms forming the armature and the other arms carrying the two movable contacts.

3. A vibratory means comprising an electromagnetic coil, a magnetic circuit for said coil comprising a centrally disposed member of magnetizable material, members of magnetizable material disposed on one end of said coil and on the sides thereof and a movable armature at the other end bridging the side and central members of said magnetic circuit, said armature being mounted solely upon the end of a coil spring and being moved bodily against the tension thereof by the energization of the coil, and contacts carried by said armature, said armature being formed in the shape of a cross with one pair of arms forming the armature and the other arms carrying the two movable contacts, said armature being mounted upon and fastened to the upper end of said spring and having an inclined opening for facilitating the insertion of the end of the wire of the spring therethrough for fastening and accommodating and firmly holding one of the coils.

4. A vibratory means comprising an electromagnetic coil, a magnetic circuit for said coil 6 comprising a centrally disposed member of magnetizable material, members of magnetizable material disposed on one end of said coil and on the sides thereof, and a movable armature at the other end bridging the side and central members of said magnetic circuit, said armature being mounted solely upon the end of a coil spring and being moved bodily against the tension thereof by the energization of the coil, 10 and contacts carried by said armature, said armature being formed in the shape of a cross with one pair of arms forming the armature and the other arms carrying the two movable contacts, said armature being mounted upon and fastened to the upper end of said spring and having an inclined openin for facilitating the insertion of the end of the wire of the spring therethrough for fastening and accommodating and firmly holding one of the coils, and a lock nut screw-threadedly attached to the projecting part of the coil spring and clamping against the armature.

5. A vibratory means comprising an electro- .rnagnetic coil, a magnetic circuit for said coil comprising a centrally disposed member of magnetizable material, members of magnetizable material disposed on one end of said coil and on the sides thereof and a movable armature at the other end bridging the side and central members of said magnetic circuit, said armature being mounted upon the end of a coil spring and being moved bodily against the tension thereof by the energization of the 'coil, and a contact carried by said armature, the centrally disposed rnember of magnetizable material being in the form of a split ring and said coil spring being mounted within said split ring with the free end thereof fastened to the armature, and forming the sole support for said armature. 40 GEORGE T. SOUTHGATE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 560,471 Chapman May 19, 1896 848,720 Broc Apr. 2, 1907 1,201,491 Neahr Oct. 17, 1916 1,215,422 Spangler Feb. 13, 1917 1,563,670 Spencer Dec. 1, 1925 1,932,164 Petit Oct. 24, 1933 2,009,892 Leece July 30, 1935 2,025,859 Hartman Dec. 31, 1935 2,040,688 Drury May 12, 1936 2,107,742 Ruben Feb. 8, 1938 2,253,602 Barrett Aug. 26, 1941 2,360,664 Field Oct. 17, 1944

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