US1660251A - Variable resistance - Google Patents

Description

Feb. 21, 1928.

W. L. BURNAM VARIABLE RESISTANCE Filed Jan. 27, 1926 1 m nkvm u o 5 Wm P3,, l m

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Patented Feb. 21, 1928.

WILLIAM LEE :Bnnmur, or KANSAS CITY, mssouar.

VARIABLE nnsrsrancn.

Application filed January 27, 1926. Serial No. 84,205.

This invention relates to a liquid rheostat which is adapted for use as static eliminator. object of this invention is to provide a. simple and eflicient variable resistance device which is adjustable and adapted to be connected preferably between the aerial and the antenna post of a radio set, whereby the resistance of the circuit can be varied and static and other disturbing frequencies eliminated.

A further object is to provide such a device which is simple to operate and durable andeconomical in construction.

The invention is illustrated in the drawings, of which Figure 1 is a side elevation of the device mounted on the panel board;

Figure 2 is a longitudinal section through the device taken on the line22 of Figural; Fgure 3 is .a longitudinal section taken at right angles to the section line of Fig- Figure 4 is a horizontal section taken on the line H of Figure 3.

The form of the invention shown in the drawings is a preferred form, although it is understood that modifications in the construction and arrangement of the parts and the character ofthe materials used may be adopted without departing from the spirit of the invention as set forth in the appended claims.

in its general aspect the invention comprises a tubular container in which a body of liquid is disposed. Disposed within the container is an adjustable electrode which may. be wholly or partly submerged in the liquid. One end of the container is c0nnected to the antenna circuit, for instance, and

the other end is connected to the radio set.

By adjusting the distance between the bottom of the adjustable electrode and the bottom of the container the resistance in circuit can be varied and it is found that this arrangement will permit radio signals to pass and at the same time will shut out the static and other extraneous noises. It also seems to decidedly improve the quality of the tone coming from the set. The adjustable electrode is manipulated by through the side of a container and may be mountednnthe side of a panel board.

' In the preferred construction shown in the drawings, the invention comprises 2; containany material w ch will hold water and is er 10, preferabliyl iin tubular form, made of a knob which extends not a conductor of electricity. The upper and lower ends of the container are closed by threaded caps 11 and 12 which are screwed on .the ends of the tube, packing rings 13 and 14 making the joint tight. The caps are provided with threaded stems 15 and 16 on which thumb nuts 17 and 18 are mounted for the purpose of permitting connection to conducting wires. Within the container or tube is a body of liquid 19 preferably water. Dependent into the liquid is an electrode 20 mounted on a rack bar 21 which is slidable in acurved guide plate 22. This guide plate is fastened against the face of an insulating block 23 which is screwed to the side of the tube 10. An insulating sleeve 24 is threaded into an aperture in the block 23 and an aperture in the side of the tube and in the panel board 25. Suitable washers 26 and 27 are disposed on each side of the panel board and threaded on this sleeve 24. Within the sleeve is a shaft 28 on the outer end of which is mounted a knob 29 with a pointer 30 traveling over a dial 31. The other end of the shaft .28 is provided with a pinion 32engaging with the rack bar 21 to move it upwardly and downwardly. As shown in Figure 2 one side of the guide plate 22 is split to provide a spring finger 33 which will frictionally bear against theraclr bar to maintain it in any position in which it is left. The guide plate 22 supports a spring arm 34 which extends upwardly therefrom and bears as at 35 against the bottom of the cap 11, thus making the circuit contact with the binding post stem 15, the caps 11 and 12 being of metal. It will be observed that as the knob 29 is operated to raise and lower the rack bar the distance between the bottom of the electrode 20 and the cap 12 through the liquid 19 can be varied, thus varying the resistance introduced into the circuit by reason of this liquid path through which the signal currents have to pass. It is the provision of this variable liquid path in the circuit, preferably the antenna circuit, which seems to cause the improvement in the operation of the set and in the elimination of static.

What I claim is:

1. In a variable resistance, a liquid receptacle of insulating material provided with metal caps having means for securing circuit wires thereto, a guide member in the receptac le, a rack mounted in the member, an electrode carried by the rack, a pinion meshing with the rack, means for operating the pinreceptacle of insulating material provided ion, and a member carried by the guide mem' with removable metal caps having threaded her and permanently engaging the upper stems on which thumb nuts are mounted, an cap of the rece tacle. insulating block secured to the casing, a guide 2. In a varia le resistance, a liquid recepsecured to said block, a rack slidably mounttacle of insulating material provided with ed in the guide, an electrode secured to the metal caps having means for securing circuit lower end of the rack, a spring carried by wires thereto, a guide member in the recepthe guide and engaging the rack, an insutacle,a rack slidably mounted in the memlating sleeve in openings in the insulating her, a spring carried by said member and enblock and the receptacle, a shaft mounted in gaging the rack to hold it in position, an the sleeve and provided with a knob at its electrode carried by the rack, a pinion meshouter end, a pinion on the inner end of the ing with the rack, means for operating the shaft and meshin with the rack, and a pinion, and a member carried by the guide spring arm secure to the guide and permamember and permanently engaging the upnently engaging the upper cap of the recepper cap of the receptacle. tacle.

8 In a variableresistance, a tubular liquid 4 WILLIAM LEE BURNAM.

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