US2488375A - Permeability tuning slug support - Google Patents

Description

Nov. 15, 1949 R. c. CARLSON 2,488,375

PERMEABILITY TUNING SLUG SUPPORT Filed March 28, 1945 r .1. INVENT OR.

FH/BEN C. CARL SON fi -'4 ATTORNEY Patented Nov. 15, 1949 UNITED STATES PATENT PERMEABILITY TUNING SLUG surron'r Reuben C. Carlson, Chicago, Ill., aulgnor to Admiral Corporation, of Delaware Chicago, lll., a corporation Application March 28, 1945, Serial N0. 585,357

1 Claim.

This invention relates to tuning controls such as are used in connection with permeability tuned receivers and more particularly to an apparatus for providing a more perfect alignment of the tuning elements for a receiver.

Although the invention about to be described will be described in connection with permeability tuning controls for radio receivers, it will be apparent that the invention is also useful in connection with certain types of controls other than those used in permeability tuning.

As is well known to these well versed in the art, it is desirable, in connection with radio' circuits, to provide an apparatus whereby certain of the circuits may be tuned to difierent frequencies. In some types of receivers, this is effected by varying the capacity and in others by varying the inductance. Varying the inductance is commonly effected by moving a core or slug composed of finely divided iron into proper relation with the inductance winding. Usually this is done by sliding a cylindrical slug into the form which carries the winding. This presents a problem during production, because the slug must fit closely in the coil form so that it cannot move accidentally and cause the tuning to change. The slug must still slide freely into the coil form and therefore the alignment of the slug with the form has to be carefully controlled otherwise it will not slide in,

and out with case.

In commercial production this is somewhat difficult, making it necessary to have precision controls and increasing the cost of the receiver. This problem becomes more acute as the number of slugs to be moved is increased, as in the case of a superheterodyne or multiband receiver where a number of circuits are tuned simultaneously.

By the present invention I am enabled to provide a slug supporting means which allows the slug to readily align itself with the coil form. By utilizing my improved slug support, I am able to increase the production of tuners and eliminate the necessity of precision controls. The improved supports also permits rough and course adjustments to readily be made during the construction of the receiver.

Other advantages of the invention and the invention itself will become more apparent from the following description of an embodiment thereof, which description is illustrated by the accompanying drawings and forms a part of this specification.

In the drawings:

Fig, 1 is a side elevational view of a tuning con trol assembly embodying my invention;

Fig. 2 is a vertical sectional view taken on the line 2-2 of Fig. 1;

Fig. 3 is an enlarged fragmentary vertical section through one of the slug supports and showing a fragment of a slug in elevation;

Fig. 4 is a fragmentary plan view thereof;

Fig. 5 is a view similar to Fig. 3 of a modified form of the invention;

Fig. 6 is a fragmentary plan view thereof; and

Fig. 7 is a fragmentary perspective of the end of a wrench for adjusting the device of Fig. 5.

In carrying out my invention, I preferably provide a connector which may be adjustably connected to a control member and which carries flexible means that in turn carries a tuning member; the flexible means permits movement of the flexible member and it in turn permits lateral movement of the tuning member allowing it to automatically align itself with the means being tuned.

Referring now to the drawings throughout which like parts have been designated by like reference characters and particularly to Figs. 1 and 2, I have illustrated a tuning sub-assembly which may be built up separately from the re-' ceiver chassis and be attached thereto in any suitable manner.

The assembly includes a support for the coils and their forms, a carriage for supporting the tuning slugs and a control means for moving the carriage.

As is shown in the drawings, the tuning assembly includes a frame or chassis of open sided construction comprising sheet metal side walls I, 2 and 3 and a bottom wall I. The coil forms 5 are carried by the bottom wall 4 being supported thereon in any desired manner and carry thereon inductance windings as indicated at 6.

The wall i is provided with an angularly disposed bracket 1 which extends at right angles to the wall and is provided with a tongue 8 extending parallel to the wall I. A shaftv 9 is journalled through the wall I and the tongue 8, and carries thereon a sheave it. The shaft may be locked against removal from the tongue by a split ring H seated in a groove in the end of the shaft. The bracket 1 is also provided with ways i2 that slidably support a slide i3 which is-.-of L-shaped formation and carries on its end a plate It. A cable i5 is secured at I6 to the slide being trained around the sheave l0 and has the other end secured by a spring I! to a lug l8 on the other end of the slide. When the shaft 9 is rotated the slide i3 is slid carrying with it the plate It.

The plate [4 is adapted to carry and control the positioin of a plurality of slugs which, when the plate I is moved, project into or are withdrawn from the coil forms. As previously mentioned, there may be any desired number of these forms. In the particular illustration there is shown four such forms and they are disposed in spaced parallel relation to each other.

The plate H is provided with a plurality of threaded apertures 2|, Fig. 3, in which are screw 0 threaded bushings such as shown in Fig. 3. Each bushing comprises an exterlorly threaded cylinuses" der 22 having a bore 23 extending most of the way through the cylinder, and provided with an annular flange 24 on one end, and a flattened portion 25 on the other end. The slug, illustrated at 26, as previously stated, comprises a core of iinely divided iron and has secured therein during the manufacture thereof a wire or rod like member 21 which is imbedded in the slug as indicated by the dotted line 28. The member 21 has a certain amount of flexibility and extends through the bore 23 of the cylinder and through the opening in the end 25. It may project beyond the end as indicated at 29.

In installing the device it is common practice to first roughly align the circuits by sliding the slug 26 in and out of the coil form, the wire 21 sliding in-the opening 25. Preferably the bushing 22 is positioned by threading it through the plate ll for such a distance as to permit subsequent maximum adjustment thereof in either direction. The support wire 21 is then slid in the bushing, and the slug in the coil form to provide a rough adjustment. The wire 21 may be then soldered on the end at 29, or the material of the bushing may be upset or crimped to hold the slug permanently therein. After the rough adjustment is made, it is then possible to more accurately align the circuits by adjusting the slug to its proper position relative to inductance by engaging the flattened end 25 with a suitable wrench or tool and screwing the bushing 22 in or out of the opening 2|.

Inasmuch as the means for holding the coil forms sometimes does not hold them exactly vertical or parallel to each other and also because there may be slight discrepancies in the position of the slug bushings 21 in the plate I4, considerable difficulty was sometimes had securing sufficiently accurate alignment of the slugs with the coil forms.

It will be noted that the support rod or wire 21 extends through the sleeve 23 and is secured at the end of the sleeve remote from the slug and that there is ample room between the rod and the interior of the sleeve in which space the rod may move. Since the rod is flexible, it is thus possible for the slugs to tilt in entering the coil forms or to be tilted by the coil forms and thus allow the coil forms to automatically align the slugs therewith. This could not readily be done if the connection were a rigid connection. Also by this structure the rod 21 has an effective length considerably greater than it should have if it was connected at the end 24 of the member 22. This permits for greater flexibility of the device and allows a compact assembly to be made which does not take up a great amount of room in the receiver.

It will be seen therefore that the structure lends itself to preadjustments during the building of the receiver and to fine adjustments after the receiver is built and when the final alignment of the components are being made. Furthermore, with this structure stampings may be used for the control and a considerably cheaper type of construction may be realized. The necessity for precision controls is thus eliminated and the operation of the device is made effective through the utilization of my invention. It will also be seen that the structure is cheap, easy to install and simple to manufacture.

In Fig. 5, I have shown a slight modification which has certain advantages resulting in ease of operation and economies of manufacture. The upper end of the bushing, instead of being flattened as shown at 25 in Fig. 3, is plain. This eliminates the operation of providing the flattened end. The slug rod or wire 21, in this instance, extends through the end of the bushing, and after being roughly adjusted. as previously described, is bent over at 21', with the bent over portion lying flat against the end of the bushing. The end preferably extends beyond the side of the bushing.

After being bent over, the wire may be soldered to the end of the bushing. Because there is a greater area which may be soldered, it provides a more secure connection for the wire, and the end which extends beyond the side of the bushing provides a convenient means for subsequent adjustment.

For adjusting the bushing a wrench formed as best shown in Fig. 7 may be provided. This wrench comprises simply a cylindrical body 20, the inside diameter of which is sufliciently large to allow it to be slipped over the bushing, and provided with diametrically opposed slots 2| either of which may slip over the wire 21'. This wrench may have one or more slots, only one at a time, however, having its walls in engagement with the wire 21'.

It will be seen, therefore, that this structure lends itself to a cheaper and yet more effective construction.

Having thus described my invention in an embodiment thereof, I am aware that numerous and extensive departures may be made therefrom without departing from the spirit or scope of the appended claim.

I claim:

In a permeability tuner having tuning slugs and a movable frame, means for adjusting said slugs and connecting them to said frame comprising a semi-flexible wire extending from said slug, an adjustable member in threaded engagement with said frame, and formed with an axially extending bore closed by an end wall remote from the slug, said wire extending into the bore in said adjustable member in spaced relation to the wall of the bore, and adapted to extend through said end wall, and movable longitudinally thereon for coarse adjustment and arranged to be fixed in said end wall to provide final adjustment by rotating the member in the threads, said wile having an end portion extending exteriorly beyond said end wall and bent laterally and adapted to be fixedly secured to the end of said adjustable member, said bent portion being provided with a point, extending beyond the side of the adjustable member, adapted for engagement with a wrench.

REUBEN C. CARLSON.

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

UNITED STATES PATENTS Number

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