US2565611A - Preselector tuner - Google Patents

Description

1951 A. J. KOVACH 2,565,611

PRESELECTOR TUNER Filed March 5, 1948 3 Shegts-Sheet l Aug. 28, 1951 A. J. KOVACH PRESELECTOR TUNER Filed March 5,' 1948 5 Sheets-Sheet 2 mwmn 30m 268 SEN.

A. J. KOVACH PRESELECTOR TUNER Aug. 28, 1951 3 Sheets-Sheet 3 Filed March 5, 1948 INST/Pl/CT/O/VS 14D VEET/Z/IVG Patented Aug. 28, 1951 UNITED STATES PATENT OFFICE PRESELECTOR TUNER Andrew J. Kovach, Gary, Ind. Application March 5, 1948, Serial N 0. 13,250

4 Claims. (Cl. 173-328) This invention relates generally toIradios and more particularly to an improved preselector tuner unit which maybe used in conjunction with conventional radio broadcast receivers to tune to desired radio programs at predetermined times in accordance with selections made on a novel control card.

The tunerof this invention is particularly well adapted tocontrol a receiver tuned on the standard broadcast band (550 to 1500 kilocycles) where programs are generally changed at exact quarter hour (or multiples thereof) intervals. With this tuner, programs may be selected in advance for a six-hour period. provision being made to turn the set on tuned to any one of a number of stations, to turn it off, or to select a difierent station at fifteen minute intervals throughout the period. By making slight changes in the control cards and associated mechanism the total period could be varied to cover an entire day and the selection interval made a different length.

Another object of this invention is to provide a a preselector tuner which is a combination radio receiver and local oscillator unit that rebroadcasts a signal to a conventional radio receiver tuned to the rebroadcast frequency.

Another object of the invention is to provide a preselector tuner which can be incorporated as original equipment in a radio receiver or transmitter or as accessory equipment for existing radios or transmitters.

Another object is to provide an automatic preselector having a manual push button control which overrides the automatic control.

Another object is to'provide a preselector unit which automatically deenergizes the radio set to which it is attached when no reception of any program is desired.

A further object is to provide atuner in which all power consuming elements except the time clock ar deenergized duringthose periodswhen no program is'received, but which automatically energizesall its componentsas well as theradio being controlled when a program is to be received.

A further object is to provide a novel, inexpensive control card which may be readily set by punching to preselect the programs desired, which card can be used as an advertising medium if desired, or sold as replacement elements.

Another object is to provide a novelcard in which conducting material printed upon the card serves to carry or control the current and circuits in the preselector tuning device.

Other and additional objects and advantages of this invention will of course present themselves to those familiar with the art on reading the following specification in conjunction with the drawings and the appended claims.

In the drawings:

Fig. 1 is a schematic wiring diagram showing a portion of the circuit of this invention;

Fig. 2 is a wiring diagram showing the remainder of the circuit;

Fig. 3 is a view showing the novel controlcard;

Fig; 41s a view of the back side of the card;

Fig. 5 is an end view showing the manner in which the card is folded;

Fig; 6 is an enlarged vertical section of a portion' of the card; and

Fig. 7' is a wiring diagram showing the electrical circuit which is the'equivalent ofthe preferred form of control card.

The circuit of this invention may best be understood by reference to Figs. 1 and 2 simultaneously. Fig. 1 shows predominately the tuning and selecting arrangement, while Fig. 2 shows the amplification, detection and output modulation stages.

The incoming radio waves are received by an antenna I0 (Fig. 2)' and set up oscillations through the condenser II and the coil I2. From the 0011 I2 the Waves are impressed through another condenser I3 on the control grid of a radio frequency amplifier'tube I 4.

The plate of the tube I4 is connected through a condenser I5 to the control grid of the detector tube I6 and also through a coil I8 to the plate supply conductor II. One set of the tuning variable condensers shown in Fig. 1 is connectedto the points marked XX in Fig. 2. The second set of tuning variable condensers shown in Fig. 1 is connected, to the points marked Y-Y' in Fig. 2.

The plate of the detector tube I6 is connected through a resistor I9 to the plate supply conductor IT and through another resistor 20 and a condenser 2| to the'control grid of a beam power amplifier tube 22.

The output of the tube 22 is applied to a transmitting antenna 23-through a condenser 24. The plate is also connected through one winding of a transformer 25 and a condenser 26, in parallel, to the plate voltage supply. The secondary winding of the transformer 25 is connected in the cathode supply to the tube 22. Connected in this manner the tube 22 serves as an oscillator and generates oscillations according to the resonant frequency of the transformer 25 and condenser 26. These oscillations are in turn modulated by the audio frequency output of the detector l6 so that a modulated radio frequency wave is applied to the antenna 23.

Thus the circuit shown in Fig. 2 receives radio waves, amplifies them, converts them to audio frequency, generates constant radio frequency oscillations, and modulates these oscillations to rebroadcast the incoming signal at a different constant frequency regardless of the frequency of the original waves.

The power supply is conventionally a half wave rectifier tube 30 being connected across the A. G. line and its output being filtered by a network to resistors 3| and 32 and condensers 33, 3A and 35 before being applied to th condutocr H.

The filaments of the four tubes indicated at 35 are connected in series with a resistor 31 across the A. C. line 38 with electrical power controlled thereto as hereafter described. A potentiometer .40 is provided to adjust the output of the circuit.

The tuning and preselection portions of the circuit are shown in Fig. 1. Tuning is accomplished by inductance 45 and variable capacitances 46 selectively connected across the grid and cathode radio frequency amplifier tube I4 and matching inductance 41 and variable capacitances 48 connected across the detector tube I6. This portion of the tuning circuit is not unlike the conventional push button tuning circuits in general use, one tuning unit being provided for each station available for selection. For convenience of illustration, five station tuner units have been shown, but the number of units provided may be varied by merely paralleling the circuit shown or deleting som of the units.

Separate units are selectively connected to the circuit by relays 50 provided for each unit, each relay being illustrated as divided into two components 56 and 56a for purposes of convenience. The double throw switches 49 of components 56 are normally in a position wherein one end of the condenser unit 48 is short circuited to its other end. When energized, the shorted end of the respective condenser 48 isconnected to a conductor 52 leading to the grid lead Y on Figs. 1 and 2. The other ends of the condenser units 48 are permanently connected to th common ground Y.

The relays 50 however can be in actuality double relays comprising a double throw switch and a single throw switch both actuated by independent but series connected solenoids The ends of the tuning condensers 46 are connected to the common pole of the double throw switch 5!. The other poles of the double throw switches are connected to common ground X which is normally contacted, and grid lead X which is normally open. The single pole switches 39 are normally open to be employed as self-holding switches in connection with-the push button tun- ,ing arrangement.

From the above it will be seen that each tuning unit is normally shorted out of the circuit and connected only when its relay unit is energized. Thus it follows that the apparatus is automatically tuned to a given station when the corresponding relay unit is energized.

The relays 5i! and 59a are preferably actuated by direct current and for this purpose a selenium rectifier 55 is connected in the line circuit from the extension cord plug or pronged connector 56.

This rectifier permits only direct current to fiow through the conductors 51, 58, 60 and 6! which carry the solenoid control current. A condenser 62 is connected across the rectifier 55 when the solenoids are energized in order to smooth out the pulsating direct current produced by the rectifier.

From the rectifier 55 the conductor 58 leads to a switch 63 controlled by a time clockwork 64. This switch 63 is arranged so as to be closed momentarily each quarter hour by the clock 64 along with a switch 66 which produces a volt pulse through electromagnet 59 to move step switch 65 to the next position.

A relay 68 is provided which serves to connect the step switch 65 to the conductor 58 when closed. This relay 68 is provided with a holding connection 68a to keep the relay energized when the time switch 63 is open. Thus the common terminal of the step switch 65 is energized all of the time except when the relay 68 is deenergized as when the device is manually operated with push button control or a circuit beyond the step switch 65 is open, depending upon the control card 10 shown in Figs. 3 to 6, as will be described later.

In Fig. '7 the circuit equivalent to the card 10 is shown. From each terminal of the step switch 65 a plurality of conductors H extend to contactors l2. Each contactor 12 corresponds to a quarter hour period during the three hours contemplated by the card controls. The coils of each of the relays 50 are connected to a similar series of contactors 13 arranged in the card holder at right angles to the first series by conductors M.

The card 10 shown in Figs. 3 to 6 comprises a folded piece of paper having lines of conducting material printed or stenciled thereon. One set of lines 15 corresponds to the contactors 12 when the card is folded, a line being provided for each quarter hour. The other set 16 perpenoucular to the first and printed on the reverse side of the card corresponds to the contactors 13, one line being provided for each tuner unit.

If the card 16 were merely folded, no contact would be made between any of the conducting lines 15 and 16, but by bending out certain ones of precut tabs 18 and folding them back underneath as shown in Figs. 5 and 6 contact is made between separate horizontal and vertical lines. By proper location of the cuts and folded tabs 18, any horizontal time line 15 may be connected to any vertical station line 16.

Thus the card is set by bending out and folding tabs 18 to preselect certain programs for a given time. For this purpose indicia may be printed on the reverse side of the flap ma as shown in Fig. 4 to aid in bending out the appropriate tabs 18. The other flap 10b may or may not be provided or used, but if it is provided it may be used for advertising instructions and as a protective cover for the conductors on fiap 10a.

When a properly punched card I0 is inserted in the card holder (not shown) the electrical result is to connect individual terminals of the step switch 65 to individual relay coil leads 14, and when the step switch 65 is closed to a terminal which is connected to a relay lead 14 the corresponding relay 50 is energized. Due to the fact that when a particular relay unit is energized, its corresponding tuner unit is connected to the radio frequency stages of the circuit of Fig. 2, control of the output of the pre-selector unit depends on the position of the step switch 65 and the folding out of the card tabs.

Thus when the step switch 65 moves to a position where a relay lead 14 is energized the radio station to which the corresponding tuner unit is tuned will play for a fifteen minute interval. At

the end of-this time the step-switch will move to the next position causing. the relays 50. to;be deenergized and the. tuner disconnected; I If a tab 1 8: correspondingto. the nextf'quarter hourperiod 'in the card has. been punched, airelay unitwillbe energized for the next fifteen minutes and a second station will be-heard. I

In order to provide a manual push buttorl'con- 'trol which will override the preselection on the card, a" push button control switch 82 hasbeen provided for each tuner unit. These switches are single throw single pole switches which are normally closed in one direction, opening when the buttons are pushed. The switches 82 are connected in series with a conductor 83 which delivers D. C. power to the solenoid 68. When any one of the switches 82 is pushed, the supply of current to the relay 68 is cut off and this relay closes in the opposite direction to energize a conductor 84 connected to other single pole single throw switches 19, each of which are normally open, but close to establish an energizing circuit through the relay coil leads 14 so that when a push button is actuated, control current is supplied directly to corresponding relay coils, the card being by-passed. When'the relay coils are energized in this manner they function in exactly the same manner as described above to control the tuning of the apparatus.

The single pole normally open single throw switches 69 of the relays 50 serve as holding switches to hold the relays 50 closed from the time the push button switch is momentarily closed until the end of the one quarter hour period. At the end of this period the time switch 63 functions to energize and close the relay 68 in the opposite direction and break the supply of cur-- rent to the single pole elements Of the relays 50.

Another relay 85 is connected so that its coil is always in series with the coils of the relays 50 so that the relay 85 is closed whenever any one of the relays 50 is energized. The relay 85 controls the supply of current to the conventional radio receiver (not shown) which is plugged into a receptacle 86 instead of into the wall outlet. When the relay 85 is closed the receptacle 86 is energized, as well as the radio tubes shown in Fig. 2 as per the line leads 38. Thus the conventional receiver and the preselector are turned on only when a program is to be received.

At the top of Fig. 1 the electrical equivalent circuit for another type of control card is shown. The card in this case is not shown but merely consists of a paper rectangle which has horizontal markings corresponding to each quarter hour interval and vertical markings corresponding to each station available for selection. To make selections, the card is merely punched to provide a hole at the intersection of the appropriate time lines and station lines.

In the card holder a pair of mating contactors is provided for each possible time and station combination. When a card is inserted, the pairs of contactors are prevented from touching except where a hole has been punched in the card. In Fig. l the pairs of contactors are indicated at 90 and the card at 10. Actually the rows of contactors 90 corresponding to separate stations are parallel rather than in line as shown. If, in Fig. 1, the rows of contactors 90 connected to each of the conductors 14 were rotated so as to lie along a line perpendicular to the paper, the actual arrangement would be approximated. The electrical functioning of this modified arr'a-ngem'ent is substantially the same-' as the preferred embodiment described above.

' From the above description ofmy inventionit will be seen thata novel preselector tuner has been provided which may be adapted to" control any conventional radio receiver or-transmitter within-the'stated objects, without the necessity Ofmodifying the receiver, and programs are preselected b'y the novel control card, including the reception of frequency modulated broadcast as well as amplitudemodulated broadcasts.

Although several embodiments of this invention have been described,- it is not intended that the invention be limited to this embodiment, and changes or modifications such as will occur to those familiar with the art may be made without departing from the spirits of this invention whose scope is defined by the following claims.

What is claimed is:

1. A card of insulating material having two parallel folds therein dividing the card into three approximately equal portions, a plurality of spaced vertical lines of conductive material on the center portion, a second plurality of spaced horizontal lines of conductive material on one of the side portions, said pluralities of lines being on opposite sides of the card so as to be insulated from one another when the card is folded, the unlined side of the card serving to enclose and insulate one of said pluralities of lines, and punched reversely folded tabs on one of said portions for making electric contact through the card from lines of one plurality to lines of the other.

2. A card of insulating material having a fold 'therein dividing the card into two adjacent 1ying portions, a plurality of spaced parallel lines of conductive material on one portion, a second plurality of spaced parallel lines of conductive material on the other portion, said pluralities of lines being perpendicular to each other and on opposite sides of the card so as to be insulated from one another when the card is folded, and punched reversely folded tabs on one of said portions for making electric contact through the card from lines of one plurality to lines of the other.

3. A card of insulating material having two parallel folds therein dividing the card into three portions, a plurality of spaced parallel lines of conductive material on the center portion, a second plurality of spaced parallel lines of conductive material on one of the side portions, said pluralities of lines being perpendicular to each other and on opposite sides of the card so as to be insulated from one another when the card is folded, the unlined side of the card serving to enclose and insulate one of said pluralities of lines, and punched reversely folded tabs on one of said portions for making electric contact through the card from lines of one plurality to lines of the other.

4. A substantially rectangular card having two parallel folds therein dividing the card into a first side portion, a middle portion, and a second side portion, one edge of said card being outwardly ofiset along the middle portion to provide a projection thereon and said folds being so disposed that the first side portion is narrower than the middle portion, a plurality of spaced parallel lines of conductive material on the front face of the middle portion extending onto said projec tion, a second plurality of spaced parallel lines on the rear face of the second side, and punched nent-over tabs in one of the lined portions for making electrical contact between individual conductors on opposite faces of the card, the lines ofconductive material on the middle portion being covered by the side portions except for the ends of said lines on said projection and the lines on the second side portion except the ends near the ,fold line being covered by the first side portion when the side portions are folded inwardly over the middle portion.

ANDREW J. KOVACH.

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

Number 8 UNITED STATES PATENTS Name Date Odell Jan. 17, 1882 Moore June 8, 1915 Ducker Nov. 1, 1932 Lake Mar. 15, 1938 Oldenboom July 4, 1944 Matt Jan. 16, 1945 Magnusson Nov. 27, 1945 Eisler May 25, 1948

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