US2585844A - Tuner construction - Google Patents

Description

Feb. 12, 1952 I R. ROMERO 2,585,844

' TUNER CONSTRUCTION Filed Se t. 27, 1950 7 I27 (20 F/Li 5:

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Patented Feb. 12, 1952 TUNER CONSTRUCTION Robert Romero, Forest Hills, N. Y., assignor to Leonard Electric Products Corp., Brooklyn, N. Y., a corporation of New York Application September 2'7, 1950, Serial No. 186,941

3 Claims.

The present invention relates to improvements in television tuners, and more particularly to structure for associating a vernier condenser therewith for the local oscillator thereof.

Tuners herein concerned with, are of the class having various inductances housed within a casing with means to alter the inductance in circuit, operated by the turning of a shaft. Also, the vernier condensers are of the type which are adjusted by the turning of a shaft. In a tuner combined with such condenser, it is practical that one of their respective shafts shall be tubular so that the other lie within it in concentric relation; the outer shaft serving as a bearing for the inner. Where such pair of shafts are together for more than just a very few inches in length, any slight variance of the inner shaft from true straightness would render free turning thereof difficult, and even normally, the friction between such shafts is appreciable.

Further, mounting the shafts, presents various mechanical difliculties, since it is desired that the casing walls shall support them and construction should be such to afford easy assembly and economical manufacture.

It is therefore an object of this invention to provide a novel and improved construction in concentrically associated shafts of the character mentioned, which is free of undue friction between the shafts and permits easy turning of both of them although there be a variance from true straightness in either of them.

Another object thereof is to provide a novel and improved construction in concentrically associated shafts of the nature set forth, which permits proper and easy assembly with the tuners casing.

A further object of this invention is to use a vernier condenser of novel and improved construction and so associate it with the casing of the tuner, as to shield the condenser in order to avoid interference with other circuits, ordinarily occasioned in condenser operation, and to better stabilize the local circuit.

Another object hereof is to provide novel and improved constructions in tuner and vernier condenser combinations of the character described, which are convenient and economical in manufacture and efficient in carrying out the purposes for which they are designed.

Other objects and advantages will become apparent as this disclosure proceeds.

In the accompanying drawings forming part of this specification, similar characters of reference indicate corresponding parts in all the views.

Fig. 1 shows a television tuner embodying the teachings of this invention. The view here shown is fragmentary, partly in section, and is taken looking into the casing, which would be a front view of the casing as particularly is shown in Fig. 4.

Fig. 2 is a side view of Fig. 1, with part of the casing wall shown broken away in order to expose the vernier condenser I provide herein.

Fig. 3 is a diagrammatic view of the electrical circuit portion which includes said condenser and tuner.

Fig. 4 is an exploded view showing in perspective, several of the components included in the embodiment shown in Fig. 1.

Fig. 5 is a magnified, fragmentary sectional view taken through the tubular shaft at lines 5-5 in Fig. 4, and also showing a portion of the inner shaft.

In the preferred embodiment shown in the drawings, the numeral I 5 denotes the metal casing for the drum indicated generally by the numeral l6, which is securely mounted in any suitable manner on the inner shaft H. The outer shaft I8 is tubular, and at one end which is mounted on the casing, is formed with the annular channel l9 between shoulders 20 and 2|. A small plate 22 has a hole 23, whereby it is set on shoulder 20, rather loosely. A metal plate 24, whose periphery 24' is a spiral with respect to the hole 25, is secured on the shoulder 2|. The ends of the shafts are machined with flats as at I1 and I8 respectively, for the mounting of proper hand knobs not shown, but well known in the art.

It has heretofore been the practice that the shafts be in rotatable contact fit along the entire length of the tubular shaft l8. This has proven objectionable as explained. I therefore take a piece of tubular stock whose bore is larger than the diameter of the inner shaft I1, and before machining its ends exteriorally as shown, I swage a comparatively short region at each end of the tube to bring the bore down in such end regions to a size which is a little less than the diameter of the inner shaft. Then I pass a reamer through the tube so that both ends have bores like 26, affording suitable bearing fit for the inner shaft I'l, while in the remainder of the tubular shaft l8 there is the annular clearance 21, when the shafts are assembled.

The tuner l6 may be of the type including a plurality of insulative strips 28, arranged as staves carried by end plates as 29. On the under surface of each of these strips 28, are carried inductance coils 30 of predetermined value, whose terminals are connected to contact buttons as 3|, which when the drum is turned, come into contact with brushes 32, thereby bringing desired coils in circuit. Several of these parts mentioned are not shown in Figs. 1 and 2, because they are well known in this art, and do not concern this invention. To properly position the drum at each of its operating positions, an end plate 29 may be provided with suitably spaced notches 33, for selective engagement by a spring detent 34.

The vernier condenser which I use, employs the spiral-shaped plate member 24, and a pair of spaced metal buttons 35 and 36 on a piece 31 of insulative material secured within the casing by means of a bracket 38. mounted as will be explained, the plate member 24 will be positioned in a plane parallel to the plane of the faces of the metal buttons 35 and 36, and spaced therefrom a predetermined distance. Said plate member 24 has no electrical connections thereto. It is said button members 35 and 36, which are respectively electrically connected to the terminals of the inductance 30 in circuit, by means of the brushes 32; said buttons being respectively connected electrically to said brushes.

The casing I is provided with an open bearing 39 to receive the inner shaft I! in annular channel 40, and in its opposite wall with an open bearing 4| to receive the outer shaft H3 in annular channel l9. With their heads exterior the casing, screws 42 pass loose through holes 43 in plate member 22, and threadedly engage the casing wall in the threaded holes 44. A stiff spring wire 45 is positioned as shown in Fig. 2, to engage the shanks of the screws 42 on one side and the tubular shaft l8 on the other side, so that said shaft is maintained in contact with the halfround edge 4| of the bearing 4|. Similar spring and its engagement means may be provided to maintain the inner shaft I! in contact with the half-round edge 39. It is evident that removal of the spring means mentioned and the screws 42, permits removal of the shafts I7 and I8 with the components they carry, from the casing IS. The condenser indicated generally by the numeral 46, being positioned within the metal casing, is thereby shielded against causing objectionable disturbances which may be occasioned by its operation.

It is to be noted that the plate 22 serves particularly to prevent damage to the drum l6 and the casing l5, which would be occasioned if accidently a severe force were applied at the forward milled ends of the shafts in a direction outwardly of the open bearing 4 I.

It is also to be noted that the foregoing man- When the shaft I8 is ner of construction and association of condenser and casing, has proven an aid in materially reducing electrical noise.

This invention is capable of numerous forms and various applications without departing from the essential features herein disclosed. It is therefore intended and desired that the embodiment herein shall be deemed illustrative and not restrictive and that the patent shall cover all patentable novelty herein set forth; reference being had to the following claims rather than to the specific description herein to indicate the scope of this invention.

I claim:

1. In an apparatus of the character described, the combination of a container having an open mouth, an elongated tubular shaft having an exterior annular channel whereby a reduced portion exists intermediate the ends of said tubular shaft; said container having an open bearing in a wall thereof of a size to admit said reduced portion whereby an end of the tubular shaft is positioned through said mouth in a lateral direction, a detachable plate adapted to be mounted on the container to close said bearing; said plate being carried loosely on the tubular shaft, spring means on the container, pressing the tubular shaft in a lateral direction, an inner shaft positioned through the tubular shaft and extending outwardly from each end thereof and means to hold the shafts against relative longitudinal movement; the walls of the channel being substantially in contact with the respective surfaces of the wall of the container; the tubular shaft being rotatable in said bearing and the inner shaft being rotatable with respect to the tubular shaft.

2. An apparatus as defined in claim 1, wherein the tubular shaft has a reduced bore at each end portion thereof serving as bearings respectively for the inner shaft.

3. An apparatus as defined in claim 1, wherein an annular space exists between the shafts within and intermediate the ends of the tubular shaft.

ROBERT ROMERO.

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

UNITED STATES PATENTS Number Name Date 1,608,526 Potter Nov. 30, 1926 1,906,857 Heyne et a1 May 2, 1933 2,496,183 Thias et al. Jan. 31, 1950 2,532,263 Silvey Nov. 28, 1950

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