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Publication numberUS2375178 A
Publication typeGrant
Publication dateMay 1, 1945
Filing dateOct 1, 1941
Priority dateOct 1, 1941
Publication numberUS 2375178 A, US 2375178A, US-A-2375178, US2375178 A, US2375178A
InventorsSamuel Ruben
Original AssigneeSamuel Ruben
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Variable electrical resistor
US 2375178 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

May l, 1945. s. RUBEN 2,375,178

VARIABLE ELECTRICAL RESHISYTOR Filqd oct.""1,'1941 2 sheetsshet' 1 fffw I N VEN TOR.

cfazfme/ uen TTORNE Y May l, 1945. RUBEN 2,375,178

VARIABLE ELECTRICAL RESISTOR Filed oct. 1, i941 2 sheets-sheet 2 90A/00d /v/ yynsssyJ BY .Samuel Enkel@ H TT URN E Y resistors.

their constructionare` stable in operation and Patented May 1, 1945 UNITED STATES PATENT FFIG'LE 2,375,178 A VARIABLE nLEormoAL nnsls'ron samel Ruben, New Rochelle, N. Y. Application october 1, 194,'1, serial No. 413,135' s claims. (c1. aol-o) '.lnis invention relates resistors.

An object of the invention is the provision of avariable resistor of new and improved construction which can be conveniently and economically manufactured, which is stable land which can be used to replace variable wire wound resistors of the prior art as well as variable re sistors of' the carbon pile type. A further object is the provision of an improved variable resistor of the compression type. Other objects will be apparent from the disclosure and from the drawings, Fig. 1 of which to variable electrical is a view partly in section, of a variable resistance device made according to this invention; Fig. 2 is a detail of one section of the resistance element not under compression; Fig. 3 is a detail of the same section oi the resistance element under compression and Fig. 4 is a graph illustrating the performance of the resistor in respect to pressure versus resistance, rotation versus resistance and temperature rise watt dissipation. f

The` art discloses two general types of variable One is the wire wound type utilizing the variation in resistance obtained by contacting the resistance element at various points along its length by' a conductor in the form of a. rotating sliding contact, or by bringing out connections from various points to the resistor element, contact to which is made by a sliding arm contact or lever. Variable resistance elements of this type are' also made utilizing a carbon base resistor instead of wire. The other type is the compression type which functions by reason of the contact resistance lvariation between materials having negative pressure resistance coeiicients such as carbon or which function by the compression of a mixture of powder or ilake carbon or graphite with an insulatingmaterial such as mica powder.

Each of these types has an inherent limitation` that is, inability to directly dissipate its heat without a high temperature gradient from the hottest portion to the heat radiating surfaces.

Ihe resistor of this invention allows the dissipation of heat more effectively from the resistor element andy permits the construction o! units having a much higher power capacity with volume. Also it allows the construction ci a resistor having a much longer life than the present compression type due to the fact that unlike carbon compression types which lose their surface, the units may be adjusted or repeatedly compressed at the same pressures with approximately the same resistance values.

Another factor of importance with the present resistoris that a large resistance range can be obtained'with a small angular change of the control pressure.

The invention comprises the impregnation into and onto the fibres of a glass mat or cloth of a resistor] material such as colloidal graphite, and the heating up of the impregnated glass mat to the point where the resistance material is rmly and permanently bonded to the glass. The preferred impregnating material is colloidal graphite. Other resistor materials such as platinum may be used, in which case the glass mat is impregnated with a platinic chloride solution and then baked'to the required tempera-` ture, such as 350 C., thus bringing about decomposition of the chloride and deposition of a thin platinum lm. It is also possible to utilize a very thin depositsoi nickel as the resistance material by heating the glass mat to 250 C. in a nickel carbonyl atmosphere.

In carrying out the invention, the glass fibre mat, preferably about 20 mils thick, -a'nd containing a large number of thin glass bres, is placed in a container in which is a solution of 20% by weight of colloidal graphite (Aquadag). The aquadag is in an aqueous solution to which a small amount oi ammonium hydroxide has been added to ins-ure colloidal suspension (l c. c. of 28% N'HiOI-l per liter of water). A low pressure is applied to'allow the air between the fibres to be exhausted and after a period of about iiiteen minutes the glass bre'mat having thereon a deposit of colloidal graphite is taken out of the impregnating solution and passed through a rubber/roller under pressure so as to eliminate -excess material. It is then baked for thirty minutes at-a vtemperature of about 300 C. As a result oi' thisbaking the colloidal graphite is firmly bonded to the glass fibres and the glass mat may be then punched into discs or squares with mounting holes 'of a .size dependent upon 'the application. By variation of the colloidal graphite content various ranges of intial resistance values canbe obtained For some applications an ammonium sheilac solution in the order of 5% of the graphite content may be added. This is a clear red solution completely miscible with the dolloid. It decomposes during the baking, adds to the bonding `of the graphite to the glass and increases the resistance to water vapor ell'ects.

In the construction of the variable resistance units electrodes/ of good heat' conductivity are positioned on both sides of the resistor discs, preferably at the minimum pressure required to secure good contact.v The resistivity is high due to the long resistance 'paths along the fibres. When compressed the variousbres are brought together to .provide an increasing number of multiple paths (due to contacting together of the libres) which lowers the resistance inv proportion to pressure.

In order to illustrate the construction of a typical unit and the performance of such a unit, reference is made to the drawings.

In Fig. 1 is shown a variable resistance device of this invention in which the resilient springlike glass fibre mat resistor element 3, separated by brass heat-radiating plates 8', is contacted by.

end plates i and 2 of #5 thickness aluminum or brass. A ceramic tube l0, is riveted to the back end plate l, serving as a guide and to keep the plates from rotating. Centrally located ceramic tube 5 is placed on thread screw 6, which is attached to the back end plate l. At the thread end the knob 'l containing a threaded metal insert B and further insulated from the end plates by glazed ceramic washer 9 is used to apply the pressure to the resistor elements. This glazed washer also reduces the turning friction of the knob.

By the use of spacer washers of various thick- -ness to increase the space between the radiator plates the amount of heat radiation and loss can be regulated.

In the unit described, the radiator plates have an areaJ 3" square and are maintained Ik" apart -by use of spacer washers. The impregnated glass mat resistor elements are 21/2 in diameterand a 32 pitch compression screw has been use d in order to regulate the operation.

In Fig. 2 is shown a detail of one of the resistor sections of the device. The impregnated glass The graph of Fig. 4 illustrates the operating characteristics of a resistor built according to the design illustrated in Fig. l.

The three curves, pressure against resistance, rotation against resistance and watts against temperature rise are self explanatory and illustrate the wide range of utility of the device.

The variable resistance device of this invention allows a Wide range of control, inasmuch as the sections may be connected in series, in parallel or in series parallel, and still have a control throughout the entire'range of adjustment. This is not possible with wire wound variable resistorsor compression type resistors.

Having described my invention what Iv claim as new and desire to secure by Letters Patent, is: l. The method of making an electric resistance element which comprises immersing a resilient glass 4fibre mat containing a large number of criss-crossing thin glass iibres in an aqueous ammoniacal suspension of colloidal graphite to deposit colloidal graphite on said libres, removing said mat from saidsuspension and extracting excess liquid therefrom and then baking said mat to bond said colloidal graphite thereto.

2. The method of making an electric resistance element which comprises immersing a resilient glass fibre mat containing a large number of criss-crossing thin glass bres in an aqueous ammoniacal suspension of colloidal graphite to deposit colloidal graphite on said bres, removing said mat from said suspension and extracting excess liquid therefrom and then baking said mat to bond said colloidal graphite thereto, and then .inserting said mat between parallel plate electrodes in contact therewith.

3. 'I'he method of making an -electric resistance element which comprises immersing a resilient mat l I is shown housed between contactor plate I2 and i3. The mat is not under operating pressure and the long current path length can be noted.

In Fig. 3 the same resistance section can be shown under compression and it is obvious that the current path has become much shortened due to parallel paths andcontacting together of the libres lla.

glass bre mat containing a large number of ,criss-crossing thin glass bres in an aqueous ammonium resin solution containing a suspension of colloidal graphite, to thereby deposit colloidal graphite and resin'on said fibres, removing said mat from said suspension and extracting excess` liquid therefrom and then baking said mat to decompose said resin and bond said graphite to said glass fibres.


Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2645701 *May 10, 1951Jul 14, 1953Johnson Matthey Co LtdElectrical resistor and resistance elements therefor
US2666835 *Jul 24, 1951Jan 19, 1954Ici LtdElectric resistance welding process
US2694743 *Nov 9, 1951Nov 16, 1954Bakst AaronPolystyrene grid and separator for electric batteries
US2779729 *Jul 1, 1950Jan 29, 1957Dow Chemical CoCathodic protection assembly
US2847319 *Apr 26, 1954Aug 12, 1958Ohio Commw Eng CoGas plating of aggregates
US2847972 *Mar 19, 1956Aug 19, 1958Rosenthal Sidney NStamp pads
US2953849 *Aug 27, 1956Sep 27, 1960Owens Corning Fiberglass CorpReinforcement of metal
US2978665 *Jul 11, 1956Apr 4, 1961Antioch CollegeRegulator device for electric current
US2979424 *Sep 17, 1953Apr 11, 1961Owens Corning Fiberglass CorpMetal coated glass fibers and method of making them
US3069487 *Jan 4, 1960Dec 18, 1962West Point Mfg CoMiniature photocells and method of making the same
US3097941 *Jun 21, 1952Jul 16, 1963Union Carbide CorpMethod and apparatus for gas plating of metal on glass fibers
US3206618 *Mar 15, 1963Sep 14, 1965Kallmann Heinz ENegative resistance devices
US3209298 *Oct 31, 1961Sep 28, 1965Westinghouse Electric CorpArrangement for controlling circuit conductivity
US3247020 *Jan 2, 1962Apr 19, 1966Owens Corning Fiberglass CorpElectrically-conductive elements and their manufacture
US3252071 *Oct 3, 1962May 17, 1966FulmenElectrical regulating device
US3386067 *Apr 24, 1967May 28, 1968Raphael J. CostanzoPressure-sensitive electrical switch and application therefor
US3451032 *Jul 15, 1966Jun 17, 1969Omsteel Ind IncElectromechanical transducer material
US4227410 *Apr 13, 1979Oct 14, 1980Emdee CorporationAttitude compensating indicator
US4235141 *Sep 18, 1978Nov 25, 1980Eventoff Franklin NealElectronic apparatus
US4334350 *Mar 7, 1980Jun 15, 1982Chemotronics International, Inc. ShareholdersMethod utilizing a porous vitreous carbon body particularly for fluid heating
US4358956 *Mar 17, 1980Nov 16, 1982Emdee CorporationLiquid level indicator
US4906192 *Dec 16, 1987Mar 6, 1990Smithard Michael AElectronic computerized simulator apparatus
US5578765 *Jun 1, 1995Nov 26, 1996Incontrol Solutions, Inc.Transducer array
US5583303 *Jun 1, 1995Dec 10, 1996Incontrol Solutions, Inc.Transducer array
US6469266Mar 9, 2001Oct 22, 2002International Road Dynamics Inc.Road vehicle axle sensor
US6646540 *Jun 21, 2000Nov 11, 2003Peratech LimitedConductive structures
US7186356May 30, 2002Mar 6, 2007Peratech Ltd.Analytical device
US7345670Jun 26, 2001Mar 18, 2008AnascapeImage controller
US8674932Jun 10, 2005Mar 18, 2014Anascape, Ltd.Image controller
US9081426Sep 30, 2005Jul 14, 2015Anascape, Ltd.Image controller
US20060028435 *Sep 30, 2005Feb 9, 2006Armstrong Brad AImage controller
US20060028436 *Sep 30, 2005Feb 9, 2006Armstrong Brad AImage controller
US20060028437 *Sep 30, 2005Feb 9, 2006Armstrong Brad AImage controller
EP0018185A1 *Apr 11, 1980Oct 29, 1980eMDee CorporationAttitude compensating indicator
U.S. Classification29/621, 338/52, 427/383.5, 338/99, 29/419.1, 29/620
International ClassificationH01C10/10, H01C10/00
Cooperative ClassificationH01C10/106
European ClassificationH01C10/10C