US2735072A

US2735072A - Wire-range radio-frequency tuner

Info

Publication number: US2735072A
Authority: US
Publication date: 1956-02-14
Anticipated expiration: 1973-02-14

Description

Feb. 14, 1956 I, R. VERSOY, JR

WIDE-RANGE RADIO-FREQUENCY TUNER Filed Aug. 25, 1952 J %)IVNVENTORI M fiw ATTORNEYS.

WISE-RANGE RADIO-FREQUENCY TUNER Irving R. Verso Jr., Norwalk, Cnn., assignor to Aladdin Industries, Incorporated, Chicago, 111., a 'CDIPOIQUOROQ Illinois Application August 25,1952, Serial No. 396,157

6 Claims. .(Cl. 333-24) This invention relates to tuners for V. H. F. and U. H. F. circuits, particularly to tuners adapted for use in applications requiring a Wide range of frequency variation.

Specifically, the present invention relates to wide-range tuners of the type embodying a pair of energy-transfer elements and an inductor having non-uniform inductance per unit length, the inductor being movable relatively to both the energy-transfer elements.

in one advantageous form of such tuners, the energytransfer elements are fixed in position with respect to one another, the inductor being axially movable through or alongside the transfer elements. The exchange of energy between the inductor and the energy-transfer elements is preferably accomplished by capacitive transfer.

A tuner of this type makes possible continuous tuning over heretofore unheard-of frequency ranges, such as 25 to 1. From the mechanical standpoint, however, such a Wide frequency range usually has required a rather extensive range of axial movement by the inductor. It is the object of the present invention to provide a widerange tuner of the foregoing character which has the advantage of requiring substantially less axial inductor movement to cover a given frequency range or series of frequency ranges. Another object of the present invention is to provide a tandem inductor arrangement which facilitates use of the aforesaid type of tuner in applications wherein a plurality of frequency bands are to be covered, rather than a continuous frequency range.

in the appended drawing, Ihave disclosed an illustrative embodiment of my invention; Fig. 1 is a perspective view showing the external appearance of a typical embodiment of my tuner; Fig. 2 is a sectional view, in the vertical plane, of the Fig. l apparatus; and Fig. 3 is a sectional view taken in a plane perpendicular to that of Fig. 2, along the line 33 of Fig. 2.

In Fig. l l have shown my tuner mounted on a suitable block 11 of low-loss insulating material such as polystyrene. Suitably secured to block 11, as by screws 12, l have provided a pair of energy-transfer elements 13 and 1 2-, preferably formed by suitable machining from relatively massive blocks of metal such as brass, copper, or aluminum. The

blocks

13 and 14 are mounted upright on base 11 and may have interposed between them a'guide block 15 of insulating material such as polystyrene.

As may be readily seen from Fig. 2, all the elements 13, 1d, and 155 are provided with a plurality of parallel bores marked respectively 16, 17, and 18. The bores in the

respective elements

13, 14, and 15 are arranged for registration, so as to provide a plurality of parallel passages extending entirely throughout the assembly.

As will be explained in a subsequent paragraph, inductors are adapted to slide within the

bores

16, 17, and 18, and the function of the insulating block 15 is to insure that all the inductors are effectively guided within the bores, regardless of their axial position. In other words, the block 15 has nothing to do with the electrical performance of the invention and can .be omitted if other suitable measures are taken to prevent the inductors from 'nited States Patent 0 2,735,072 Patented Feb. 14, 1956 2. binding or jamming within the bores drilled in the

metal blocks

13 and 14.

Contact lugs 19 may be provided as desired on the

blocks

13 and 14, to facilitate the connection of an external circuit to the tuner.

As indicated heretofore, the energy exchange to and from the inductors is preferably accomplished by capacitive rather than conductive energy transfer. To facilitate that, I have provided within each of the

bores

16, 17, and 13, in all the portion of those bores within the

metal blocks

13 and 14, thin plastic inner sleeves 21. Sleeves 21 provide a thin insulating layer on the inner surfaces of

bores

16, 17, and 18, and at the same time provide a smooth low-friction surface for the inductors to slide on.

The inductors mentioned are suitably wound on a plurality of rods or forms made of suitable low-loss material. The rods are mounted in parallel relation, with spacing adapted to permit them to slide simultaneously within the

bores

16, 17, and 18. The rods are identified by

reference numerals

26, 27, and 28 respectively. As illustrative of a suitable mechanical arrangement for simultaneously sliding the

rods

26, 27, and 28, l have shown a yoke 29 rigidly receiving all the rods.

The highest-frequency inductor should normally be placed nearest the external connections to the associated tube, since the total circuit inductance is thereby reduced.

It is to be understood that my choice of three inductors and three-bore energy-transfer elements was arbitrary and for illustration only. Any desired number maybe used.

The inductor 36, wound on rod 26, is formed of wire wound on rod 26 in a manner such that its inductance per unit length is non-uniform. Specifically, inductor 36 is provided with a number of closely wound turns at the left end thereof, as viewed in Fig. 2, and the remaining turns are spaced with ever-increasing spacing.

Inductor 37, wound on rod 27, is placed in staggered position relative to inductor 36, commencing a substantial distance to the right thereof, as viewed in Fig. 2. The length of coil 37 is substantially the same as the length of coil 36, but its inductance is far less. In the illustration shown, inductor 37 is wound of ribbon having substantially equal winding pitch throughout but gradually increasing in ribbon width from the left to the right ends of the coil. As a result, the inductance per unit length of inductor 37 is also non-uniform.

Inductor 38 is made in a manner similar to inductor 37, except that it is staggered still further to the right and is made of ribbon having greater width and greater pitch, resulting in substantially less inductance. It shares, however, the characteristic of the other inductors in that its inductance per unit length is variable.

The

inductors

36, 37, and 38 are all of substantially the same length, but they vary greatly one from another in total inductance. The inductors are staggered according to the pattern which provides that only one of the inductors can at any one time bridge the insulated zone between the energy-

transfer elements

13 and 14. In the position of the

rods

26, 27, and 28 shown in Fig. 2, inductor 35 is barely bridging the space between the

elements

13 and 14, and, upon being moved slightly further to the left, inductor 36 will be closely coupled capacitively to both energy-transfer elements 13 and 14-. As further leftward movement of the inductors continues, the total inductance effectively bridged between the

elements

13 and 14 will become greatly reduced, since the closely wound portion of inductor 36 will be involved within energy-transfer element 13. This will result in reducing substantially to zero the effective inductance of the closely wound portion of the coil, leaving as the inductance effectively in the circuit that which is possessed by the portion of the coil remaining between the

elements

13 and 14.

With still further leftward movement of the inductors,

the right end of inductor 36 will pass completely beyond energy-transfer element 14, leaving inductor 36 substantially disconnected from the circuit. Almost immediately thereafter, as the rods continue to move to the left, the left end of inductor 37 will pass into intimate capacitive relation with element 13 and inductor 37 will thereby be effectively placed in the external circuit connected to lugs 19. Further leftward movement of the yoke 2 will cause the effective inductance in the circuit to be reduced still further, because of the non-uniform inductance characteristics of the coil 37.

Finally, as coil 37 moves so far leftward as to clear elementl4, inductor 38 will come into the circuit in the manner already explained.

It will be understood that any desired mechanical arrangement may be provided for the systematic axial movement of

rods

26, 27, and 28.

The outstanding advantage of the present invention over the type of prior structure heretofore discussed is that my present invention permits of wide-range tuning over a plurality of bands with a very substantially reduced linear movement of the inductors. Furthermore, it permits more gradual change of inductance with length, for any given available range of movement, and thereby provides greater bandspread and correspondingly greater ease of tuning.

While I have in this specification described in con siderable detail a particular embodiment of my invention, it is to be understood that the example shown is purely illustrative and that many changes can be made in the apparatus shown without departing from the spirit of my invention. For example, the energy-

transfer elements

13 and 14 can be of any desired conformation or length. in the drawing, 1 have illustrated the fact that one or both of the contact elements may, if desired, be elongated so as to envelop substantially all of the inductors not actually bridging the contact elements. Further, while I have herein shown the inductors wound on cylindrical forms, and have shown the cooperating bores in the energytransfer elements similarly cylindrical in shape, it will be readily seen that the invention could be practiced by the use of arcuate coil forms and arcuate bores.

Also, while I have shown insulating sleeves 21 as a means of insuring capacitive energy interchange between the

elements

13 and 14, on the one hand, and the inductors, on the other hand, the same result could be accomplished by providing the inductors with a thin insulating layer.

A related invention is disclosed and claimed in the co-pending application of Harold T. Lyman, Serial No. 305,629, filed August 21, 1952.

Such points are a matter of choice and design, and I desire them to be embraced within the scope of my invention as defined in the appended claims.

I claim:

1. A wide-range radio-frequency tuner, comprising a pair of conductive energy-exchange electrode elements fixedly spaced apart relative to one another, each of said elements being provided with a plurality of parallel transversely spaced, generally cylindrical channels therein, said channels in each of said elements being axially aligned with the corresponding channels in the other of said elements, a plurality of generally helical inductance coils axially aligned with said respective channels and mounted for longitudinal movement therein, means providing a thin layer of insulating material interposed between said coils and each of said channels to limit energy exchange therebetween primarily to capacitive energy interchange, each of said coilshaving non-uniform inductance per unit length along the length thereof, each of said coils being longer than the spacing between said electrode elements and being movable into and along a range of positions with said coil bridging the space between said elements and intimately coupled thereto in energy-exchange relation therewith, said coils being longitudinally staggered in position and rigidly mounted with respect to one another and thereby being movable successively into bridging relation between said electrode elements, with only one of said coils in bridging relation between said elements for any one position of said coils in said channels.

2. A wide-range radio-frequency tuner, comprising a pair of conductive energy-exchange electrode elements fixedly spaced apart relative to one another, each of said elements being provided with a plurality of parallel transversely spaced, generally cylindrical channels therein, said channels in each of said elements being axially aligned with the corresponding channels in the other of said elements, a plurality of generally helical inductance coils axially aligned with said respective channels and mounted for longitudinal movement therein, each of said coils having non-uniform inductance per unit length along the length thereof, each of said coils being longer than the spacing between said electrode elements and being movable into and along a range of positions with said coil bridging the space between said elements and intimately coupled thereto in energy-exchange relation therewith, said coils being longitudinally staggered and fixed in position with respect to one another and thereby being movable successively into bridging relation between said electrode elements.

3. A wide-range radio-frequency tuner, comprising a pair of conductive energy-exchange electrode elements fixedly spaced apart relative to one another, each of said elements being provided with a plurality of parallel transversely spaced channels therein, said channels in each of said elements being axially aligned with the corresponding channels in the other of said elements, a plurality of generally helical inductance coils axially aligned with said respective channels and mounted for longitudinal movement therein, means providing a thin layer of insulating material interposed between said coils and each of said channels to limit energy exchange therebetween primarily to capacitive energy interchange, each of said coils having non-uniform inductance per unit length along the length thereof, each of said coils being longer than the spacing between said electrode elements and being movable into and along a range of positions with said coil bridging the space between said elements and intimately coupled thereto in energy-exchange relation therewith, said coils being longitudinally staggered and fixed in position with respect to one another and thereby being movable successively into bridging relation between said electrode elements.

4. A wide-range radio-frequency tuner, comprising a pair of conductive energy-exchange electrode elements fixedly spaced apart relative to one another, each of said elements being provided with a plurality of parallel transversely spaced channels therein, said channels in each of said elements being axially aligned with the corresponding channels in the other of said elements, a plurality of generally helical inductance coils axially aligned with said respective channels and mounted for longitudinal move ment therein, each of said coils having non-uniform inductance per unit length-along the length thereof, each of said coils being longer than the spacing between said electrode elements and being movable into and along a range of positions with said coil bridging the space between said elements and intimately coupled thereto in energy-exchange relation therewith, said coils being longitudinally staggered and fixed in position with respect to one another and thereby being movable successively into bridging relation between said electrode elements.

5. A wide-range radio-frequency tuner, comprising a pair of conductive energy-exchange electrode elements fixedly spaced apart relative to one another, each of said elements being provided with a plurality of parallel transversely spaced, generally cylindrical channels therein, said channels in each of said elements being axially aligned with the corresponding channels in the other of said elements, a plurality of generally helical inductance coils axially aligned with said respective channels and mounted for longitudinal movement therein, means providing a thin layer of insulating material interposed between said coils and each 01' said channels to limit energy exchange therebetween primarily to capacitive energy interchange, each of said coils having non-uniform inductance per unit length along the length thereof, each of said coils being longer than the spacing between said electrode elements and being movable into and through a range of positions with said coil bridging the space between said elements and intimately coupled thereto in energy-exchange relation therewith, and means for moving said coils successively into and through said range of positions with said coils successively in bridging relation between said electrode elements.

6. A wide-range radio-frequency tuner, comprising a pair of conductive energy-exchange electrode elements fixedly spaced apart relative to one another, each of said elements being provided with a plurality of parallel transversely spaced channels therein, said channels in each of said elements being axially aligned with the corresponding channels in the other of said elements, a plurality of generally helical inductance coils axially aligned with said respective channels and mounted for longitudinal movement therein, each of said coils having non-uniform inductance per unit length along the length thereof, each of said coils being longer than the spacing between said electrode elements and being movable into and through a range of positions with said coil bridging the space between said elements and intimately coupled thereto in energy-exchange relation therewith, and means for moving said coils successively into and through said range of positions with said coils successively in bridging relation between said electrode elements.

References Cited in the file of this patent UNITED STATES PATENTS Re. 19,232 Dalpayrat July 10, 1934 1,258,423 Lowenstein Mar. 5, 1918 2,250,366 Frisbee July 22, 1941 2,589,092 Kihn et a1. Mar. 11, 1952 2,622,203 Kiebert, In, et al Dec. 16, 1952 FOREIGN PATENTS 425,329 Great Britain Mar. 12, 1935