US3008882A - Process of making magnetic amplifiers - Google Patents

Description

Nov. 14, 1961 P. H. CRAIG 3,008,882

PROCESS OF MAKING MAGNETIC AMPLIFIERS Original Filed Feb. 13, 1956 INVENTOR. PALMER H .7 CRAIG ATTORNEY United States PatentO 3,008,882 PROCESS OF MAKING MAGNETIC AlVIPLIFIERS Palmer H. Craig, 1042 Catalonia Ave.,

Coral Gables, Fla. 7 Original application Feb. 13, 1956, Ser. No. 565,192, now Patent No. 2,937,351, dated May 17, 1960. Divided and this application Oct. 26, 1959, Ser. No. 852,921

6 Claims. (Cl. 204-) v This invention relates to a process for manufacturing magnetic amplifiers.

Such magnetic amplifiers comprise, in general, a magnetic core material having two or more windings so placed thereon that direct current in the saturating (input) winding produces partial or complete saturation of the core, changing the effective inductance of the power (output) winding and thereby varying the amount of alternating current passed by that winding.

Other devices, particularly radio tubes and transistors, are commonly used as amplifiers of audio and radio frequencies. As compared with such devices, magnetic amplifiers are extremely rugged, will last almost indefinitely, require no warm-up time or filament or-cathode current, will respond to extremely high frequencies and will withstand much higher temperatures. In addition, they can be made to have magnetic memory not possessed by either vacuum tubes or transistors. For these reasons, magnetic amplifiers are used in computers, switching devices, servo systems, and in numerous other devices' The present application is a division of my application Serial No. 565,192 filed February 13, 1956, issued as Patent No. 2,937,351 on May 17, 1960.

The present manner of manufacturing magnetic amplifiers is to first produce ferrite cores by mixing iron oxide powders with other components such as nickel oxide, then pressing this mixture into a toroidal or other desirable shapes and sintering the shaped material in the presence of oxygen. After the cores have been pro duced, coils of insulated wire are wound thereon by a rather difiicult winding operation requiring special winding machines, the number of turns, windings, etc. being determined by the characteristics desired of the magnetic amplifier being produced. As can be readily seen, the magnetic amplifiers produced by this method are ex pensive, too costly to be usedas a substitute for relatively inexpensive radio tubes and transistors and are used only in those circuits or devices in which only magnetic amplifiers may be used. Asa result, magnetic amplifiers are used today in guided missiles and computers where cost is of secondary importance.

The present invention contemplates the manufacture of magnetic amplifiers which are inexpensive in cost and susceptible of mass production methods whereby large quantities of these amplifiers may be produced simultaneously. A suitable core or a plurality of cores, as many, as desired toroidal in shape or otherwise, is first deposited by an electroplating process on a backing plate made of insulating material. This process requires an electrolyte or electroplating bath having the capability of depositing cores of nickel-iron or other suitable alloy, the composition of said electrolyte forming a part of this invention. After the cores have been formed, windings are then wound or deposited thereon, or a conductive paint applied on the cores in a manner described in detail hereinafter.

Therefore, a principal object of the present invention is to produce magnetic amplifiers by a novel method of electro-depositing the cores in anelectroplating operation whereby from a single to hundreds or thousands of such units may be produced simultaneously.

A further object of the present invention is to provide following has been found effective.

3,008,882 Patented Nov. 14, 1961 ICC magnetic amplifiers described as above wherein an electrolyte of certain composition is utilized, which results in the depositing of cores having the desired iron and nickel content.

A further object of the present invention is to provide a method of manufacturing magnetic amplifiers which are light in weight, rugged in construction and inexpensive in cost.

A still further object of the present inventionis the provision of a method of manufacturing magnetic amplifiers characterized as above which may be used in radio and television circuits, computers, servo systems, switching devices, etc, and can serve as memory devices in mechanisms requiring such a characteristic.

With these and other objects in view, as will appear hereinafter, my invention consists of certain combinations and processes as will be hereinafter described in detail in connection with the accompanying drawing and particularly set forth in the appended claims.

In the drawing:

FIGURE 1 is a plan view of a normal toroidal core mounted on a backing plate.

FIGURE 2 is a sectional view taken along the line 2-2 of FIGURE 1.

FIGURE 3 is a similar view to that of FIGURE 2.

showing a modified form of my magnetic amplifier.

FIGURE 4 is a top plan view of a still further modification of the invention.

FIGURE 5 is a sectional view taken along the line 55 of FIGURE 4. i

As in the normal electroplating and electro-depositing processes there are required an electrolytic bath, a cathode, an anode, and a source of electrical energy whereby a flow of ions is created carrying a metallic deposit of desired characteristic from the anode to the cathode. For depositing an alloy of approximately 40% iron and'60% nickel at the cathode, an electrolyte comprising of the G./l. Nickelous sulfate, crystals 180-200 Nickelous chloride, crystals 40.- -Ferrous fluorborate 2- 40 Boric acid 20- '40 Suitable wetting agent. 2 Q

Examples of suitable wetting agents are sodium lauryl sulphate, or photographic wetting agents. In general sulfonic acids or their salts prepared from aromatic petroleum compounds, alkylated with monochlorinated kerosene, and in turn sulfonated may be used.

The pH of the above solution should .be 2.5 to 3.5 and itshould be used at a temperature of 50 to 60 degrees centigrade. Ferrous sulphate crystals can be used instead of the ferrous fluoroborate, using the same concentrations. To obtain higher percentages of iron in theironnickel alloy which is being plated, use higher concentrations of the ferrous salt. When using ferrous sulphate, add 15 g./l. of nickel tfluoroborate to assist in keeping any ferric iron formed in solution as a complex. The wetting agent is used to prevent pitting of the deposit. Higher rates of deposition can be obtained by omitting the nickel sulfate and using sufiicient nickel chloride to make the same total nickel content. The bath should be treated with activated carbon in a quantity of approximately 4 g./l. of solution, and the solution filtered to remove the carbon. This is to remove harmful organic materials, which may be present in case the formula is compounded from technical grade materials. The higher the iron percentage the harder it is'tokeep the bath in balance.

Anodes should be an alloy of iron-nickel in the same ratio as that desired in the plated material. The anode have been thoroughly washed to remove organic materials.

My invention allows the use of diiferent techniques for producing ditferentrand special types of amplifiers.

Referring to FIGURE 1, which depicts a typical toroidal vcore 11, I begin with an'insulated plastic backing plate which is then coated with a conductive material, such as copper, silver, graphite or ,othenconductive materials.

Thebooklet PrintedCircuit Techniques which is National Bureau of ,Standards Circular 468, published by the U.'S."' Department of Commerce, gives onpages 23 and 24. several suitable. techniques for the chemical depo sition of conductivecoatings, on insulating plates, and on pages. 24-26 suitable methods for depositing such conductive coatingsby vacuum processes, cathodic sputtering and.,evaporation are. given. .By the use of the aforementioned electroly-tic bath, a corevll is then deposited on..this backing plate either through a template which 1imits.;thedeposit to the shape and sizewanted or by over thetop of the deposited cores (assuming a large number of cores were deposited simultaneously), such backing'plate having been:covered with some suitable cement or adhesive, normally one of the commonly used plastic .cements. Thedepositcd cores will adhere thereto after the cement dries. Then the new backing plate carrying :the deposited cores is separated from the original backing plate and the graphite is dusted or removed therefrom by selective chemical baths which will remove such con .ductive materials Without-removing the deposited core material. There is now left an insulator plate on which there ,are affixed the deposited cores in whatever shape and sizedesired. 'This shape and size have, of course,

,beencontro-lled by the original template or masking technique. Any parafiin remaining on the cores 11 is removed by immersion in benzine or other-suitable solvent. After the deposition of the core 11, an insulating film 13 is placed thereon as'by spraying an acrylic resin (plastic) over the desiredarea.

The next step in the present, process, is the depositing ofmwindings on, core 11. By using a masking technique a suitable conductive paint is painted or sprayed on the cores in the form of individual wires. In thisoperation a series of parallel conductivepaths or wires 12 are positionedon the cores slightly departing from a perpenidicular to, the -,axis, ofithecore onwhichthey are being placed. ,There will be as many of. these parallel wires as .there are to. be turnsron this winding. These wires extend over the edge of the core and then terminate either ina rivet, 14 (see FIGURE 2) extending through the insulating' backing plate 10 or in a hole 15 (see'FIGURE 3) j formedat that point, there being a hole 15 or rivet 14, for each terminal of each turn of such wire 12. Thus if there were to be 100 turns in that winding, there would beZOO such holes 'or rivets, .all being formed with one operation. In the case of the rivets 14, as shown by FIGURE 2, the. turns make contact electrically with the rivets 14. In the. case of the holes, as, shown by FIGURE 3, these holes. 15 can be treated with conductive paint, so that. there is a conductive path 16, from front surface to there-ar surface of the insulatingbacking plate, such pathv being .confined, of course, to that particular spot, there being in the case of 100 turns, 200 such conductive paths. Now thebacking plate is turned over and another series of; such turns orwire 17 deposited on the opposite side, each making contact electrically with the cbnductive holes 15 or rivets 14 in the plate 10, so that these wires form the other. side of the turns. The template or maskingte'chniques should, of. course, include a connecting core-before starting to apply the windings.

deadfrom each end-of such a coil, or the'coilcouldbe tapped at any desired place, by a connecting lead being placed there. Electroplating techniques could, of course, be substituted for the conductive paint. In the instance where the plated alloy is of high electrical resistance it may not be necessary to :insulate the core before applying the windings, "but it has been found: necessary in most instances to insulatethe core'.before the windings are applied. This caneasilyibe done by applying an insulating varnish, lacquer, plastic or other suitable coat on the Many other techniques .of assembly offthe, magnetic cores deposited bythis electroplatingprocess may obviously be carried out, without departing from the scope of the present in- .vention.

Windings may be applied in the conventional manner as, illustrated by FIGURES 4 and 5 wherein bobbins or .winding devices are .used for windingcoils of insulated wires 20about the. closed cores 11. In this instance, the backing. plate10. is slotted or provided with openingsli ,19 -and.21, adjacent the outer and inner sides, respectively .of the core.-11. The openings 19, 21 are sufiiciently large to permit the bobbin to fit therethrough as the windings Zilare positioned on the: core 11.

Many.windings can be deposited or paintedon simultaneously. Successive layers of core, insulated from one another, may becasily produced and each such core layer may be extremely. thin, thus lowering losses and making the use of very high frequencies feasible. Successive layers of windings each insulated from the other may also be employed. The present method'allows the magnetic amplifier thus made to be a memory device if sodesired, and a wide variety of formulas in the core i available by the use of suitable baths in the electroplating operation and the use of anodes composed of desired alloys.

Y amplifiers.

Having described by invention, what I claim as-new is: l. A method of manufacturing nmagnetic amplifiers comprising the placing a core-shaped coating of conductive material: on an insulated "backing plate, immersing said backing plate in an electrolytic bath to constitute a cathode, immersing an anode of magnetic metal alloys in said electrolyte, said anode having substantially the same ratio of metals as desired in the core to be deposited on said backing plate, eifecting the .deposit of said anode material on said conductive coating material .to form a core thereon by applying windings on said core, forming a plurality of electrically conductive paths through said backing plate adjacent said inner and outer edges of said core, forming a plurality of 'further electrically conductive paths over said core and the portion of said backing plate over which the core has been deposited, so that the end portions of said further electrically conductive paths join said first named paths to form a continuous electrically conductive coil about said core.

'2. A method of manufacturing magnetic amplifiers comprising the coating of an insulated backing plate with an-electrically conductive material, said coatingforming a plurality of core shapes, inserting a plurality of rivets through said backing plate adjacent said core shapes, immersing said backing plate in an electrolyte, immersing an anode of magnetic material in said electrolyte; effecting a deposit of particles of said anode on said coating on said backing plate to form a plurality of cores thereon, applying an insulation material on a portion ofsaid'cores, forming a plurality of conductive paths on said backing plate and on said insulation on said cores, said conductive paths being connected to said rivets toform continuous coils about each of said cores.

3. A method of manufacturing magnetic amplifiers as defined in claim 1, using an electrolytic composition for depositing said core for the magnetic amplifier comprising 190 parts of nickelous sulfate crystals, 60 parts of nickelous chloride crystals, 30 parts of ferrous fluorborate, 30 parts of boric acid and .7 part of a wetting agent.

4. The process of making magnetic amplifiers,.comprising depositing electrolytically a core material on an insulated backing plate having a conductive coating constituting the cathode while masking said plate to define the desired shape of the cores, depositing coil half turn portions over the outside of said core and on the opposite side of said insulated material, making a series of apertures alongside said cores, and depositing conductive material in said apertures to join the successive half turns of said coil portions on opposite sides of said plate.

5. The process of making magnetic amplifiers, comprising depositing electrolytically a nickel-iron alloy core material on an insulated backing plate having a conductive coating constituting the cathode, using a mask on said plate to define the desired shape of the cores, transferring the cores to a plate of insulated material, depositing coil half turn portions over the outside of said core and on the opposite side of said insulated material, making a series of apertures alongside said cores, and depositing conductive material in said apertures to join G./l. Nickelous sulfate, crystals; 180-200 Nickelous chloride, crystals -80 Ferrous fluorborate 2-40 Boric acid 20-40 and a suitable wetting agent, and maintaining a pH of said solution substantially 2.5 to 3.5, and a temperature of substantially to C.

References Cited in the file of this patent UNITED STATES PATENTS 1,563,731 Ducas Dec. 1,1925 2,721,822 Pritikin Oct. 25, 1955 2,792,340 James May 14, 1957 2,927,066 Schaer Mar. 1, 1960 OTHER REFERENCES Printed Circuit Techniques, Nat. Bureau of Standards Circular 468, November 15, 1947, pages 17 and 18.

Claims (1)

1. A METHOD OF MANUFACTURING MAGNETIC AMPLIFIERS COMPRISING THE PLACING A CORE-SHAPED COATING OF CONDUCTIVE MATERIAL ON AN INSULATED BACKING PLATE, IMMERSING SAID BACKING PLATE IN AN ELECTROLYTIC BATH TO CONSTITUTE A CATHODE, IMMERISING AN ANODE OF MAGNETIC METAL ALLOYS IN SAID ELECTROLYTE, SAID ANODE HAVING SUBSTANTIALLY THE SAME RATIO OF METALS AS DESIRED IN THE CORE TO BE DEPOSITED ON SAID BACKING PLATE, EFFECTING THE DEPOSIT OF SAID ANODE MATERIAL ON SAID CONDUCTIVE COATING MATERIAL TO FORM A CORE THEREON BY APPLYING WINDINGS ON SAID CORE, FORMING A PLURALITY OF ELECTRICALLY CONDUCTIVE PATHS THROUGH SAID BACKING PLATE ADJACENT SAID INNER AND OUTER EDGES OF SAID CORE, FORMING A PLURALITY OF FURTHER ELECTRICALLY CONDUCTIVE PATHS OVER SAID CORE AND THE PORTION OF SAID BACKING PLATE OVER WHICH THE CORE HAS BEEN DEPOSITED, SO THAT THE END PORTIONS OF SAID FURTHER ELECTRICALLY CONDUCTIVE PATHS JOIN SAID FIRST NAMES PATHS TO FORM A CONTINUOUS ELECTRICALLY CONDUCTIVE COIL ABOUT SAID CORE.

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