US2577542A - Friction generator - Google Patents

Description

Dec, 4, 1951 J, RQUDAUT 2577 542 FRICTION GENERATOR Original Filed March 5, 1950 FIG. I M

HALOGENATED HYDROGARBON ,ANERT HYDROCARBON FIG.2

IIIIIIIIIII FIBROUS HALOGENATED HYDROCARBON VEN TOR.

"QM W Patented Dec. 4, 1951 FRICTION GENERATOR Jean Roudaut, New York, N. Y., assignor to Chatham Electronics N. J., a corporation of New Jersey Original application March 3, 1950, Serial No. 147,492. Divided and this application October 25, 1950, Serial No. 192,060

Claims.

1 This invention relates to friction generators of the type which is fully described in my copending application, Serial No. 147,492, filed March 3, 1950, now Patent No. 2,572,765, issued October 23, 1951, for Friction Generator, of which the present application is a division.

Friction generators are quite old in the art of generation of electricity and were among the first mechanical appliances to be used in connection with early experiments on electrical phenomena. Some of the first generators used a sphere of sulphur rubbing against a cloth. Others used ebonite (hard rubber) and glass in various forms rubbing against pads of silk, leather and felt. One of the most emcient friction generators used a rotating glass disk with leather pads pressing against the disk surface. An amalgam of tin was sometimes spread on the leather surface to increase the available current.

All the above generators produced electricity when the temperature of the component parts was kept above the freezing temperature of water. At temperatures lower than 0 centigrade, no voltage was generated. Since prior art generators are generally used only in the class room to demonstrate electrical phenomena, such a limitation was no disadvantage. However, during recent years, small high voltage friction generators have been used to charge instruments used for the detection and measurement of nuclear radiation and some of these instruments are used in airplanes where the temperature is as low as 70 centigrade. For such an application, friction generators must be made of materials which do not change their electrical characteristics with temperature.

A series of experiments with many types of friction materials in varying conditions of temperature and humidity has disclosed the fact that all the prior art friction materials required a small amount of moisture to function properly. Silk, wool, cotton, glass, and nylon work best when the surrounding atmosphere has a humidity of about fifty percent and a temperature which lies within the range of to 40 centigrade. Chemically, these materials are characterized by the presence of NH2. OH, COOH, or other hydrophile groups.

A group of materials has been found which does not depend upon humidity or moisture for the generation of friction electricity. This group may be given the general classification of halogenated hydrocarbons and includes polyvinyl chloride, tetrafluoroethylene, and trifiuoro-chloroethylene. A more definite classification of this Corporation, Newark.

group is non-hydroxyl halogenated hydrocarbon polymers. When a rubbing pad from this group is used with a disk of an inert hydrocarbon such as methyl methacrylate or polystyrene, a friction generator is produced which will work in a dry atmosphere or in a temperature range from to -70 centigrade. A more definite classification of this latter group is nonhydroxyl hydrocarbon polymers.

One of the objects of this invention is to provide an improved friction generator which avoids one or more of the disadvantages and limitations of prior art arrangements.

Another object of the invention is to increase the temperature range wherein a friction can operate satisfactorily.

Another object of the invention is to provide a friction generator which will operate well regardless of the humidity of the surrounding atmosphere.

Reference is made to the following description taken in connection with the accompanying drawings.

Fig. 1 is a schematic representation of a friction generator using a solid block as a rubbing pad.

Fig. 2 is a schematic representation of a friction generator using fibrous material held by a retaining holder as a rubbing pad.

Referring now to Fig. 1, a generator is shown having the same general form as prior art generators. The generator comprises a rotor l0 which in this example'may be a fiat disk, rotatable about a shaft II. A solid friction pad I2 is resiliently held against the rotor l0 and when the rotor is turned, electrical charges are created on the edge of the insulated disk due to the rubbing action. The charges may be removed by a brush [3 which may touch the disk surface in generators which develop low voltages. In generators which develop a voltage exceeding 5,000'volts or more a spray brush, comprising a plurality of fine sharp points, may be used without making actual contact with the rotor surface.

One of the generator terminals I 4 is connected to the friction pad H which will be negative if the materials used are those designated in the drawing. The second terminal I5 is connected to the brush l3. A spring I6 is used to press the pad l2 into resilient contact with the rotor.

Due to the symmetrical nature of the structure, it will be obvious that a change in direction of the rotor will have no effect on the polarity of the generated voltage.

It will be obvious that an equally emcient generator may be constructed by using halogenated hydrocarbon as the rotor material and inert hydrocarbon as the solid rubbing pad. In this case the polarity oi the terminals will be reversed.

Fig. 2 illustrates a more efilcient type of generator employing fibrous material in the rubbing pad. This form produces the same voltage as the form shown in Fig. l, but the current available for a load circuit is increased many times. A similar rotor l and brush l3 are used as before, but a retaining holder I1 is employed in this structure to hold a mass of fibrous halogenated hydrocarbon IS. A fiat plate i9, resiliently forced by a spring 20, is employed to keep the fibrous mass pressed against the edge of rotor I0. Terminals l4 and B5 are provided as in the first example.

The examples given indicate a structure of the most simple design. It is contemplated that the new materials discovered may be used in any friction generator including the type dis-- closed in the parent application and any of the friction generators disclosed in the literature on this subject. Other types of friction generators employ several friction pads and a like number of brushes for producing higher currents.

I claim: 1. A friction generator comprising, a rotor made of an inert hydrocarbon such as methyl member and a friction pad member, one of said members made of a non-hydroxyl hydrocarbon polymer, and the other of said members made of a non-hydroxyl halogenated hydrocarbon polymer.

3. A friction generator comprising, a rotor member and a friction pad member, one of said members made of a non-hydroxyl hydrocarbon,

polymer, and the other of said members made of tetrafiuoroethylene.

4. A friction generator comprising, a rotor member and a friction pad member, one of said members made of a non-hydroxyl hydrocarbon polymer, and the other of said members made of polyvinyl chloride.

5. A friction generator comprising, a rotor member and a friction pad member, one of said members made of a non-hydroxyl hydrocarbon polymer, and the other of said members made of trifiuoro-chioroethylene.

J EAN ROUDAUT.

No references cited.

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