US1740850A

US1740850A - Radiocondenser

Info

Publication number: US1740850A
Authority: US
Publication date: 1929-12-24
Anticipated expiration: 1946-12-24

Description

Dec. 24, 1929. P. ZARAT}E. JR 1,740,850

RADIO CONDENSER Filed Jan. 13. 1926 anwnm I feel Z araie, Jr;

Cuban,

Patented Dec. 24, 1929 UNITED STATES PATENT OFFICE ONE-HALF T0 LAWRENCE W. ANDREWS, OF KANSAS CITY, MISSOURI RADIOCONDENSER Application flied January 13, 1926. Serial No. 81,004.

My invention relates to improvements in variable condensers such as are employed in connection with radio transmittin and re dio receiving apparatus, and one object is to obtain in a single instrument any desired capacity and thereby avoid the necessity of connecting up a number of units where a large capacity is needed.

A further object is to provide a variable condenser of more compact and economical construction than other variable condensers of like capacity.

Another object is to rovide a variable condenser whereby the finest selective tuning may be had with a single instrument and thereby avoid the necessity of employing several units which have to be connected in or out of a circuit to secure the desired selections.

In order that the invention ma be fully understood, reference will now be ad to the accompanying drawing, in which:

Fig. 1 is an elevation of one form of the condenser.

Fi 2 is a cross section on line 2-2 of Fig. 1, looking in the direction of arrow a.

Fig. 3 is a cross section on line 22 looking in the direction of arrow 6.

Fig. 4 is an elevation of a modified form of the condenser.

Referring more particularly to the form disclosed by Figs. 1 to 3, inclusive, 2 designates a frame consisting preferably of insulating

end bars

4 and 6, and rods 8 connecting said

end bars

4 and 6.

10 and 12 designate two rotatable conductors fixedly mounted upon

metallic shafts

14 and 16, respectively, the former of which is journaled in the

end bars

4 and 6 of the frame. The shaft 16 has one end journaled in the bar 4 and its opposite end fixed to a dielectric shaft 17 journaled in the bar 6. One end of the shaft 14 projects through a panel 18 and is provided with a fixedly mounted knob 20 carrying a dial 22, which coacts with a hxed pointer 24 on the panel 18 for indicating the extent to which the shaft 14 is rotated by said knob 20. The

shafts

16 and 17 are rotated in unison with the shaft 14 through in

tcrmeshing gears

28 and 30, fixedly mounted upon the shafts l4 and 17, respectively.

32 and 34 designate contact members secured to the end bar 4 by suitable means such as

screws

36 and 38, respectively. The contact member 32 presses at one end against the adjacent end of the shaft 14 and is provided at its opposite end with a bindin post- 40 for holding a circuit wire 41, and the contact member 34 presses at one end against the adjacent end of the shaft 16 and is provided at its opposite end with a binding post for hold ing a circuit wire 43.

44 designates a flexible conductor secured at one end to the rotatable conductor 10 and at its opposite end to a dielectric plug 46 countersunk in the rotatable conductor 12 near one end thereof. The plug 46 is preferably spaced as far as possible from that end of the rotatable conductor 10 to which the flexible conductor 44 is attached to cause the latter to wind in an advancing spiral or screw-like form upon the respective rotatable conductors instead of in superimposed eonvolutions, and said flexible conductor 44 is preferably made long and narrow so that its capacity will gradually increase as it is wound upon the rotatable conductor 12 instead of abruptly increasing and thereby rendering the condenser unfit for fine tuning. In order to prevent a short circuit from the flexible conductor 44 to the rotatable conductor 12 the latter is coated with a suitable dielectric varnish.

In practice the condenser is charged with current flowing over the

wires

41 and 43, and tuning in is effected by unwinding the flexihle conductor 44 from the rotatable conductor 10 and winding it in an advancing spiral upon the rotatable conductor 12, by rotating the knob 20. By winding the flexible conductor 44 in an advancing spiral, as hereinbet'ore stated, any selection may be had between zero, when substantially all of the flexible conductor 44 is wound upon the rotatable conductor 10, and maximum capacity when substantially all of said flexible conductor 44 is wound upon the rotatable conductor 12,115 the capacit gradually increases as the flexible con ductor is wound upon the rotatable (ouduct r 12. Likewise the capacity gradually decreases as the flexible conductor 44 is wound upon the rotatable conductor 10.

In the modified form disclosed by Fig. 4, the flexible conductor 44 is mounted upon a single rotatable conduct-or, which, however. is divided into two

sections

10 and 12 by insulation 13. The shaft upon which the rotatable conductor is fixedly mounted is also di vided by the insulation 13 into two sections [4 and 16, the latter being provided with a fixedly mounted knob 20" carrying a dial 22 coacting with a pointer 24. fixed to the panel 18-. The

shaftsections

14 and 16" are journaled in the

dielectric end bars

4 and 6", respectively, of the frame 2. A contact member 32 bears against the outer end of the shaft section 14 and is provided with abinding post 40 for holding a circuit wire 41, and a contact member 34" bears at one end upon the shaft- 16 and is provided at its opposite end with a binding post 42 for holding a circuit wire 43.

The flexible conductor 44 is connected at one end to the section 10 of the rotatable conductor and at its opposite end to a dielectric plug 46 countersunk in the section 12 of said rotatable conductor, and said flexible conductor 44* is guided from one section to the other of the rotatable conductor by a rod 15 secured to the end bars 4" and 6, so that said flexible conductor will be wound in an advancing spiral.

As in the form shown by Figs. 1 t0 3, inclusive, the capacity of the condenser may be increased from zero to maximum by unwinding said flexible conductor from the section 10" and windin it upon the section 12 of the rotatable conductor.

From the foregoing description it is apparent that important features of the invention reside in winding the

flexible conductors

44 and 44 in advancing spiral or screw like convolutions instead of in superimposed convolutions, and in making said flexible conductors comparatively long and narrow. While I have shown two forms of the invention, I reserve all rights to such other forms and modifications as properly fall within the spirit and scope of the invention as claimed.

Having thus described my invention, what I claim and desire to secure by Letters Patent, is:

1. In a variable condenser, two rotatable conductors arranged side by side, a flexible conductor connected to one of said rotatable conductors near the left end of the latter and to the other rotatable conductor near the right end of the latter so that it may be wound in an advancing spiral upon either of said rotatable conductors, and a dielectric interposed between said flexible conductor and one of said rotary conductors.

2. In a variable condenser, two rotatable conductors, a flexible conductor in the form of a strip connected to said rotatable conductors in such manner as to wind .upon either in the form of an advancing spiral, a dielectric coating on one of said rotatable conductors for insulating the latter from the flexible conductor, means for rotating said rotatable conductors, and calibrated means for determining the extent of said rotation.

3. In a variable condenser, a rotatable conductor, a flexible conductor arranged to be wound u on or unwound from said rotatable con actor to vary the capacity of the condenser, a dielectric interposed between said conductors, means for causing said flexible conductor to wind upon the rotatable conductor in an advancing spiral, and means for rotating the rotatable conductor and determining the extent of such rotation.

4. Ina variablecondenser, a rotatable conductor, a relatively long and narrow flexible conductor arranged to be wound upon or unwound from said rotatable conductor to vary the capacity of the'condenseiga dielectric interposed between said conductors, means for causing said flexible conductor to wind upon the rotatable conductor in an advancing spiral, and contacts in circuit with said rotatable conductor.

5. A variable condenser consisting of two rotatable conductors, a flexible conductor arranged to be wound in an advancing spiral upon either of said rotatable conductors to vary the capacity ofthe condenser,.a frame in which said rotatable conductors are journaled, a dielectric interposed between the flexible conductor and one of the rotatable conductors, and gearing for simultaneously rotating'the rotatable conductors.

In testimony whereof I aflix my signature.

PAUL ZARATE, JR.