US2439403A

US2439403A - Variable inductive tuner

Info

Publication number: US2439403A
Application number: US517517A
Authority: US
Inventors: Charles J H Victoreen
Original assignee: Individual
Current assignee: Individual
Priority date: 1944-01-08
Filing date: 1944-01-08
Publication date: 1948-04-13
Anticipated expiration: 1965-04-13

Description

April 13, 194s.

I C. J. H. VICTOREEN VARIABLE INDUCTIVE TUNER Filed Jan. 8, 1944 2 Sheets-Sheet 1 S :IS 1

Tree/way April 13, 1948.

C. ,Ik H. VICTOREEN VARIABLE INDUCTIVE TUNER 2 sheets-sheet 2 Filed Jan. 8, 1944 Illl e m /MQ 7 m., Ha. y.. .w e M C PatentedmApr. 13,

UNITED` STATES PATENT OFFICE 2,439,403 VARIABLE INDUCTIVE TUNER Charles J. H. Victoreen, Dayton, Ohio Application January 8, 1944, Serial No. 517,517 2 Claims.- (Cl. 171-242) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to improvements in device for tuning radio frequency amplifiers.

It is an object of the invention to provide a device for tuning simultaneously a multiplicity of circuits in a radio frequency amplifier, said device extending the range of inductance of the amplifier circuit by adjusting a variable slug 23 with sections having different permeabilities.

A further object is the provision of a device for simultaneously tuning a multiplicity of circuits in a radio frequency amplier and at the same time providing a band-width adjustable from a few kilocycles to several megacycles.

A further object is the provision of a device for varying the inductance of a circuit by sliding in a coil a core having a plurality of sections with different permeabilities.

A further object is the provision of a novel device for wide range tuning of a tuned radio frequency amplifier in which the desired characteristics are obtained by the use of ganged inductive tuning for a plurality of stages of radio frequency amplification. In accordance with the invention, the tuning is accomplished by sliding cores of different permeabilities within the inductance coils of the interstage 'transformers of the amplifier. The cores are ganged by being mounted in tandem on a single rod, which enables all of the cores to be moved simultaneously.

These and other objects are attained by the novel structure and arrangement hereinafter described and illustrated by the accompanying drawings, in which Fig. 1 is a plan view of invention.

Fig. 2 is a plan view of the device with the cover removed.

Fig. 3 is a side elevational view of the device.

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 1.

Fig. 5 is a sectional of Fig. 4.

Referring to the drawings, there is shown a casing having a lower section I and an upper section or cover 2, the casing being divided into a plurality of shielded compartments 3 in which are mounted interstage transformers. Positioned in each compartment are supporting frames i5 upon which are mounted cylindrical coil forms il of thin insulating material upon which are closely interwound the primary and secondary windings I9 and 20 of the transformers.

The tube plate and grid capacities (not shown) normally supply the capacities with which the primary and secondary coil windings I8, 20 respectively are resonant. Also on the form i1 is a device embodying the view taken on the line 5 5 26. By adjusting the tertiary circuit, the band width of the transformer can be controlled.

Extending through forms Il, which are hollow and coaxial, and through the compartments 3, is an adjustable core 4. 'Ihe core 4 is composed of a succession of

slugs

22, 23, 24 mounted on a continuous rod 25. Slugs 22 are of polyiron or other ferromagnetic material, slug 23 is of brass or similar nonferrous materials, and slug 24 is of a dielectric. The polyiron slug 22 and the brass slug 23 are partly cylindrical, fitting snugly within coil forms Il and partly tapered on one pair of adjoining ends. The dielectric slugs 24 are also cylindrical on their outer surfaces, iilling out the spaces around the tapered portions of slugs 22, 23. This construction produces an overall cylindrical structure for core 4 so that it slides smoothly within the forms I1.

Supported by an end Wall of the casing is a threaded shaft 5 on which rides a nut I2, Ilxed to a sleeve 21, which in turn is fixed to rod 25. The sleeve 21 has a slot 28 and is prevented from rotation by means of a post 29 positioned in the slot 28. By rotating shaft 5, the sleeve 21 and the rod 25 are caused to move longitudinally.

The extreme range of tuning is effected by starting with the cylindrical portion of the polyiron slug 22 wholly within the coil form Il. This is the position of maximum inductance and low- As the tapered portion of the polyiron is slid into the coil form Il, inductances 20, 2| are reduced core begins to enter the coils, the inductance is reduced still further, through the action of induced currents in the brass; and minimum 1nductance is reached when the brass slug illls the In order to provide a trimmer adjustment to line up all the stages initially and to allow :for variation of capacity from tube to tube, an adjustment is provided for shifting independently each supporting frame I5 along the axis of the core 4. In each compartment a screw 30 is prevented from longitudinal movement by a nut 3i and spring washer 32. The screw 30 threadedly engages a nut 33 which engages a U-shaped member 34 having one leg longer than the other. The long leg of member 34 engages the upper surface of nut 33 and the shorter leg engages the side of the nut. (See Fig. 4.) The member 34 is pivotally mounted at 6 and has integral therewith right angularly directed legs 31 carrycross-wise ilts o! the which modiilcations ing pins 3G in a slot l5 o! a bracket Il fixed to which is mounted :lor sliding movement along the lower section i of the casing. (See Fig. 5.) By rotating the screw 3l, the support .l5 is moved horizontally. The slots 3l prevent binding oi the pins 30, and the snug pins in the slots 3i hold the frames i5 nrmly in adjusted `positions and preserve the necessary stability of the amplifier.

The above description is to be considered as illustrative and not limitative of the invention oi can be made obviously witbout departing from the spirit and scope ci the invention as set forth in the appended claims. Thinvention having been described, what is claim 1. In an adjustable inductance device having the support I! "a easing, a plurality of trames adiustably car ried by the casing, coil means carried by each trame, a core for each coll means. carried by the casing for supporting and ior simultaneously moving all the cores with respect to the frames: means for adjusting the position of an individual frame with respect to its core comprising a screw carried by the casing. a nut on the screw. a linkage having one end connected to the nut andthe other end to the frame, so that rotation oi the screw changes the position of such individual frame V11itliuxgspect to its core;

and means 2g 2. In a tuning device for radio apparatus: a casing containing a plurality of frames each slidably mounted in the casing; a plurality of tuning means, each corresponding to one of the frames g and including two parts which are moved relatively to each other to accomplish tuning, one of the parts being carried by the casing and the other by means for e i0 the frame; and position-adjusting ach frame, these position-adjusting means including ascrew supported by the casing together with a nut and linkage controlled by movement of the screw for adjusting the position of each frame with respect to the casing. CHARLES J. H. VICTOREEN.

REFERENCES CITED The following references are of record in the E ille of this patent:

Number vNumber UNITED STATES PATENTS France Dec. 27, 1922