US2210426A - Automatic tuning mechanism - Google Patents

Description

Aug. 6,

lNvENToR W/LL/ NOA CK ATTORNEY Patented Aug. 6, 1940 UNITED STATES PATENT OFFICE AUTOMATIC TUNING MECHANISM tion of Germany Application January 23, 1940, Serial No. 315,161 In Germany October 26, 1938 Claims.

Mechanism adapted to tune radio apparatus is known in the art in which the station names on the scale member are arranged, for instance, alphabetically rather than in the order of their wave-lengths in order to facilitate the finding of a desired station. In one arrangement of this nature a stop pin serving for the setting is shifted along a slot posteriorly of which is journaled a shaft connected with the rotary condenser, me- Hl tallic disks being seated upon the said shaft which are provided with cooperating stops or detents. When the stop pin has been shifted as far as the desired station name, a separate knob serves to turn the rotary condenser until l5 it strikes.

The disadvantage of this known arrangement resides in diflicult manipulation and operation seeing that two setting means must be used; furthermore, in the fact that a distinct stop disk 20 isrequired for each station to which the apparatus is to be tuned.

f The present invention creates a simpler solution to the problem to provide an alphabetic scale in that the moving indicator member of the station scale is in coupling relation and connection with two contact disks mounted upon a shaft, one of the said contact disks carrying a row or bank of contacts of which each one corresponds to the station to be tuned to in the sequence and order of the station names on the scale, while the other contact disk has as many contacts in the sequence and disposition of the corresponding position of the tuning means, such as the rotary condenser of the receiver. Each contact mounted on one disk in this scheme is conductively united with the corresponding contact (that is, the contact coordinated to the same sending station) of the respective other disk. Two contact brushes, one of which cooperates with the first contact n disk and is stationary while the other one cooperates with the second contact disk though being connected with the tuning means, are cut in a circuit which arrests a motor setting the tuning means as a'conducting connection is es- 1 tablished between the two brushes by way of the contact disks.

Moreover, the scale bearing the station names in alphabetical order is movable and so designed that essentially only the name of the station just no tuned in will be visible behind a window formed in the wall of the box or panel. The scale more particularly is borne by a band or tape connected with the tuning means so that, even if the scale window is very reduced in size, the name of the 5 station tuned in will be easily legible even at a (Cl. Z50-4.0)

greater distance. Scales of this kind have been known in the prior art, fundamentally speaking. But in the customary arrangement of the station names in the order of their frequencies, the Search for the sending station using a scale of 5 this sort was very difficult and tedious so that it was recognized that an additional more easily readable scale was desirable.

An exemplified embodiment of the invention is shown schematically in the drawing. The knob D, which slightly projects laterally of the casing or cabinet (not shown) of a receiver and which is to serve for tuning, is seated upon a shaft A1 which supports two disks S1 and S2 made of insulation material. In the neighborhood of the periphery, that is, a portion thereof comprising 180 degrees, there are disposed the contacts K1 and K2 which may be in the form of rivets and which extend between the opposite faces of the respective disks. The number of such contact rivets to be mounted upon each disk isgoverned by the number of stations to be tuned. While the contact rivets are arranged at equal distances upon the disk S1, they are spaced on disk S2 in accordance with the positions of the rotary condenser C serving for the tuning when adjusted to the Various stations. The contact rivets K1 are engaged by a stationary wiper brush K'i, and the contact rivets K2 are engaged by a contact brush K2 attached by means of an arm or 30 lever A to the shaft of the rotary condenser A2. The shaft A1 drives by way of the dials S1 and S2 a web or endless band B stretched out between two journaled rollers W1 and W2 on which the station naines (represented by the letters A, B, C.- to S) are arranged in alphabetical order. Of these names only a small part, that is, a part comprising one or a few station names is visible posteriorly of a window X shown dotted, fitted in the wall or panel of the receiver (not shown).

Ii' a certain station name appears behind the window after adjustment of the rotary knob D, then brush K1 will engage a very definite contact rivet K1 corresponding to the desired station, let us say K. To the same station corresponds a definite rotary or angular position of the shaft A2 of the rotary condenser in which the brush Kz comes to be placed also opposite a very definite contact rivet K on the disk S2. The contact rivets K1 and K2 coordinated to the same 50 sending station, which, of course, are staggered in respect to each other at will so as to suit the deviation between the alphabetical order and the wavelength sequence, are each united with each other by a lead of which only a few, LL, LH and Lo,

are represented in the drawing. In other words, each conductor or lead connects corresponding contacts on the disks S1 and S2. For example, the conductor Lu connects the contact O in disk S1 with contact O on disk S2, etc.

Now, arrangements are so made that after setting to a certain station by the agency of the knob D, the tuning means shaft A2 must trail until the brush Kz cornes to be positioned opposite the coordinated contact rivet K2, in other words, until conducting connection has been established between the brushes K1 and K'2 by way of the particular pair of contacts K1, K2.

v corresponding to the desired station and the junction wire, say, LH. This is accomplished by conductively connecting the two brushes by way of a slide ring K3, a brush contact Ka, a relay L and a source of potential supply-Q. When energized the said relay L opens a normally closed contact T and thereby interrupts the circuit of a motor M, the shaft of which is connected through the intermediary of the friction wheels S3 and S4 or other suitable gearing with the shaft A2. In series relation to the switch T and the source of voltagesupply Q' for the motor is a change-over or reversing switch U which is shifted by meansof stops (not shown) on the rotary condenser so that by switching the potential from a clockwise winding to a winding causative of counter-clockwise rotation, or vice versa, the reversal of rotation of the setting means is insured.

Hence, the operation of the arrangement as hereinbefore described is as follows: When ytuning in on a certain station by the aid of the rotary knob D the circuit which includes the relay winding L is first broken. The motor M is excited as the contact T is automatically closed, and it thus will turn the rotary condenser of the receiver until the desired position has been attained. When this happens, the brush K2 engages the contact rivet K2 corresponding to the desired station and as a consequence closes, by

` way of a definite lead or conductor, such as Lo,

y The contact rivets may be iitted with soldering i a second motor is provided therefor.

tags or lugs in order to facilitate the work of establishing the connections LA-to Ls. In orderV to make it easier to establish the switch connections it is advisable to apply legends to the contact rivets on the disks with the corresponding call letters or wavelengths.

The Contact rivets could also be spaced around the entire circumference of the disks if the arm A is not fitted directly on the rotary condenser shaft m, but rather on a shaft connected'therewith vthrough a transmission gear whereby the range of rotation is enlarged to 360 degrees. The disks, if desired, could be replaced by drums' or equivalent means.

Also the knob D is preferably not tted directly on the shaft A1, but is connected therewith through reduction gearing in the usual way. The drive of the shaft A1 could also be by motor if A switch mounted on the outside of the receiver apparatus serves to switch it in and reverse its rotation.

The potentials for energization of the relay L and of the motor M are preferably tapped from the power unit of the receiver so that no currentwill flow when the set is switched off.

v'The band B bearing the station names is suitably translucent, and the same is illuminated from the rear in the window behind which it becomes visible. The station names are arranged in large easily legible lettering upon the band, the names being alphabetical and equi-spaced. Of course, in exceptional cases the alphabetical order may be departed from. For instance, for reception of localstations it may be expedient to provide distinct spaces placed at the beginning of band B. Moreover, the band or ribbon could also be replaced by a disk or a drum. The use of a band, however, makes for particularly good utilization of space. Inasmuch as the conventional full-view scale may be dispensed with it is possible to design the whole front panel of the apparatus to act as a bale for the loudspeaker.

What is claimed is:

1. Automatic tuning mechanism for a radio receiver provided with variable tuning means, comprising a motor for 'driving said tuning means, a pair of adjustable disks, each having a similar series of contacts, there being one contact in each series assigned to a predetermined station to be tuned in, a xed contact brush cooperating with the contacts of one of the disks, a second contact brush adapted to be rotated in unison with the tuning means and cooperating with the contacts on the second disk, a conductor joining each pair of related contacts, one on each disk, a circuit including the contact brushes, any one of the conductors with their terminating contacts and a relay, said relay adapted when said circuit is completed to break the motor circuit, thereby arresting the tuning means at the position of adjustment for receiving the p-redetermined desired station.

2. Automatic tuning mechanism as dened in claim l wherein the contacts on the disk with which the ixed contact brush cooperates are arranged in a predetermined order, and the contacts on the second disk are arranged according towavelength, each bearing a denite relation to an adjusted position of the tuning means for tuning in the predeterminedY .station to which the lcontact is assigned'.

3.` Automatic tuning mechanism for a radio receiver provided with variable tuning means, comprising a motor for driving said tuning means, a pair of disks simultaneously` adjustable step by step, each having an equal number of contacts, there being one contact'on each disk assigned to a predetermined station to 'be tuned in, a iiXed contact brush cooperating with the contactsl of one of the disks, 'a secondcontact brush adapted to be'rotated in unison with the tuning means and cooperating with the contacts on the vsecond disk, 'a conductor joining each pair of contacts, one on each disk, which are assigned to a predetermined station, a circuit including the contact brushes, any one of the conductors depending upon the adjustment of the disks, the contacts associated with said conducto-r and a relay, said relay adapted when said circuit is completed to break the motor circuit, thereby arresting the tuning means at the position of adjustment for receiving the predetermined desired station.

4. Automatic tuning-mechanism'for'a radio receiver provided with variable tuning means, comprising a motor for driving said tuning means, a pair of manually adjustable disks, an indicator scale actuated by said disks and having the station designations appearing thereon in a predetermined sequence, each disk having a plurality of contacts equal in number to the predetermined stations desired to be automatically tuned in, one of said disks having its contacts arranged in the same sequence as the stations on the indicator scale, a Xed contact brush cooperating with said last mentioned disk, the second disk having its contacts arranged according to Wavelength, a second contact brush movable in unison with the tuning means and cooperating with the contacts on the second disk, a conductor joining each pair of contacts one on each disk, which are assigned to a predetermined station, a circuit including the contact brushes, any one of the conductors depending upon the adjustment of the disks, the contacts associated With said conductor and a relay, said relay adapted when said circuit is completed to break the motor circuit, thereby arresting the tuning means at the position of adjustment for receiving the predetermined desired station. Y

5. Automatic tuning mechanism for a radio receiver provided with variable tuning means, comprising a motor for driving said tuning means, a pair of disks mounted on a common shaft, an indicator scale adapted to be moved in unison with Said disks and having the station designations appearing thereon in alphabetical sequence, means for adjusting the disks and scale step by step to one of a predetermined number of stations, each disk having a series oi contacts arranged adjacent its periphery, the number of such contacts on each disk being equal to the number of stations desired to be automatically tuned in, one of said disks having its contacts arranged in the same sequence as the stations on the indicator scale, a xcd Contact brush cou operating With said last mentioned disk, the second disk having its contacts arranged according to Wavelength, a second contact brush movable in unison With the tuning means and angularly adjustable to contact the contacts on the second disk, a conductor joining a corresponding pair of contacts, one on each disk, which are assigned to a predetermined station, a circuit including the contact brushes, any one of the conductors depending upon the adjustment oi` the disks and indicator scale, the contacts associated With said conductor and a relay, said relay adapted When said circuit is completed to break the motor circuit, thereby arresting the tuning means at the position of adjustment for receiving the desired station.

WILLI NOACK.

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