US2248144A - Automatic radio tuner - Google Patents

Description

July 8, 1941. w. H. WESTBY AUTOMATIC RADIO TUNER Filed Jan. 5, 1938 ll Sheets-Sheet 1 kT L m 4\ i 4 g @M 4M my n L Q w w Q C E &m m m m H HH I M. A Q A WM m ,1 1 m A H--- m v4 Q H l l a W w Q July 1941.

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Filed Jan. 5, 1938 IHNVENTOR.

ATTORNEY.

July 8, 1941. w. H. WESTBY J AUTOMATIC RADIO TUNER Filed Jan. 5, 1938 ll Sheets-Sheet 3 I a, Q; Q & INVENTOR,

. W file/v27 Wasrar ATTORNEY.

July 8,1941. w. H. 'wEsTBY AUTOMATIC RADIO TUNER Filed Jan. 5, 1938 ll Sheets-Sheet 4 INVENTOR.

m HENEY Wzsmr ATTORNEY.

ViuflQod atu to 585 July 8, 1941. w. H WESTBY 8,1

AUTOMATIC RADIO TUNER Filed Jan. 5, 1938 ll Sheets-Sheet 5 INVENT OR.

J Z W. HENRY Wnrm ATTORNEY.

July 8, 1941. w. H. was-rev 8,144

AUTOMATIC RADIO TUNER Filed Jan. 5, 1938 ll Sheets-Sheet 6 O o O O 0 O O O o o 0 O o O o o 0 0 0 Q00 8 000 O 0 O O Q 0 0 Fjj BY (f/5N? W573? ATTORNEY.

July 8, 1941. w. H. WESTBY AUTOMATIC RADIO TUNER Filed Jan. 5, 1938 ll Sheets-Sheet 7 ATTORNEY.

Jul 8, 1941. w. H. was-rev ,2 8,1

AUTOMATIC RADIO TUNER Filed Jan. 5, 1938 ll Sheets-$119M. 8

INVENTOR.

HI. HENRY Warm ATTORNEY.

July 8, 1941. w. H. WESTBY 2,248,144

AUTOMATIC RADIO TUNER Filed Jan. 5, 1958 ll Sheets-Sheet 9 INVENTOR. Hen/2r lt israr ATTORNEY.

July 8, 1941. w. H. WESTBY AUTOMATIC RADIO TUNER Filed Jan. 5, 1938 ll Sheets-Sheet 11 INVENT OR.

' W. HEN/87 Wssrar ATTORNEY.

Patented July 8, 1941 UNITED STATES PATENT OFFICE AUTOMATIC RADIO TUNER Wilhelm Henry Westby, Redwood Falls, Minn.

Application January 5, 1938, Serial No. 183,466

10 Claims.

This invention relates to improvements in automatic tuning devices for radio receivers and the primary object is to provide a device for automatically tuning a conventional radio receiver to a selected station or sequence of stations at predetermined periods and intervals of time.

Another object is to provide a device of this kind which will operate to tune the radio receiver to any selected station or sequence of stations at any fifteen minute interval of the twenty-four hour day and which, once the stations are initially selected, will automatically tune the receiver to these stations at the same time each day without requiring further attention.

Another object is to provide a time control unit for an assembly of this kind wherein provision is made for the closing of any desired circuit or circuits at any selected fifteen minute interval of any day of a seven day week. It is thus possible to set up, or preselect, any combination of stations to be tuned in by the radio receiver over the course of an entire week, or in cases where the control unit is used in connection with a call or signalling system, to actuate the signal at corresponding intervals over the week. The preselected combination of circuits to be closed will, of course, repeat itself in the same sequence each week unless the combination is changed and, inasmuch as radio programs are usually the same from week to week, it will be evident that my control unit will require very little attention after having been once adjusted.

Another object is to provide a device of this kind which will operate to automatically turn on the radio receiver current as the time comes for tuning to the selected station and will do this without requiring the setting or adjustment of any additional contacts or controls whatever.

Another object is to provide such a device in a compact and simple form but which is so arranged that a relatively great number of separate stations may be automatically tuned in at any time and in any selected sequence, and also wherein means is provided for automatically setting the band switch of modern all-wave" receivers to the proper position for tuning the selected station thus making it possible to select and tune in stations in both the broadcast band and such other so-called short wave bands as are provided for in the receiver.

A further object is to provide a device of this kind which may also be used to control an electric phonograph to start and stop the same at preselected times and wherein the primary current controls for both radio receiver and phonograph are so interlocked that only one may be used at any one time.

A further object is to provide a device of this character made up of two basic and complementary units which are termed herein the time control switch or clock and the radio receiver tuner or tuning unit. The time control has means for closing any preselected one, or sequence, of a plurality of separate circuits at fifteen minute intervals of a twenty-four hour day and the tuner which is connected directly to the tuning condensers of the receiver has means whereby the closing of these circuits will oscillate the con densers to various positions corresponding to the frequency of the selected radio stations. Once the condensers are thus set to the desired station they will remain thereat until the time control either selects and closes another circuit or turns on primary current to the receiver.

Another object is to provide a greatly improved time control for this purpose wherein only one movable selecting element is required for each fifteen minute interval of the entire twenty-four hour day for controlling any number of circuits thus simplifying to a great extent the setting up of a series or sequence of circuits to be closed at the desired intervals. These circuits of course represent separate stations which will be tuned in by the tuning unit as they are closed. For added convenience in thus selecting the circuits and stations to be controlled the various circuits may be colored, labeled or numbered and by cross reference with corresponding markings on the dial 0! the tuning unit any combination may be readily set up.

Another object is to provide a tuning unit of this character wherein the oscillation of the tuning condensers of the radio receiver is directly under control of a number of movable selectors which are in turn controlled and energized through the circuit closing devices of the clock in such manner that it is possible to quickly and conveniently select on the tuning unit, whether the receiver is in operation or not, any desired stations to be automatically controlled and tuned by the clock.

A further object is to provide in combination with the basic units described a manual remote control which may be connected to the tuning unit for manually controlling the operation of the same independently of the clock.

Still a further object is to provide a time control of this character which in addition to its use as a control for the tuning unit will also indicate time in minute intervals of the twenty-four hour day and will sound chimes at the quarter hours.

Yet a further object is to provide a time control which may also serve as the control for a call or alarm system in which capacity it functions with great flexibility and may be set to operate any desired signal at any, or all, fifteen minute intervals of the entire twenty-four hour day or at minute intervals of any selected hour.

The foregoing and other objects and advantageous features of my invention together with means whereby the same may be carried into ef-.- feet will be made apparent in the course of the following detailed specification, reference being had to the accompanying drawings wherein:

Figure 1 is a frontal elevation or face view of the time control, a portion thereof being broken away to disclose interior parts and the wiring being shown diagrammatically.

Figure 2 is an enlarged fragmental face view of the time control.

Figure 3 is a radial section through the time control along the line 3-3 in Figure 2.

Figure 4 is a cross section along the line 44 in Figure 3( Figure 5 is a frontal or face view of the dial of the tuning unit, a portion being broken away to show interior construction and the wiring being shown diagrammatically.

Figure 6' is a similar view of the circuit control disc as arranged behind the dial of the tuning unit, a portion of the radio receiver chassis being shown together with the tuning motor and band switch, the wiring being here also shown diagrammatically.

Figure 7 is an enlarged vertical section through the entire tuning unit and a portion of the radio receiver chassis and tuning condensers being shown as associated with the tuning unit.

Figure 8 is an enlarged vertical cross section through the insulating block supporting the band switching brushes, a portion of the adjacent chassis and circuit controlling disk being also shown.

Figure 9 is a rear elevation of the upper portion of the dial of the tuning unit showing the arrangement of the station selectors thereon.

Figure 10 is an enlarged detail view, partially in cross section, of one of the station selector elements used in the tuning unit.

Figure 11 is a fragmental sectional view, similar to the upper portion of Figure 7, and illustrating a manually actuated form of selector pin by which "touch tuning of the radio receiver may be carried out.

Figure 12 is a plan or face view of a seven day clock or time control unit for controlling the tuning unit over the course of an entire week, a portion of the dial of the unit being broken away to disclose interior construction.

Figure 13 is a fragmentary side elevation of a setting slide or tool for adjusting the station selector pins as used in the seven day clock.

Figure 14 is an enlarged fragmental and diametrical cross section along the line I4--H in Figure 12.

Figure 15 is an enlarged diametrical cross section through the indexing mechanism, along the line I5I5 in Figure 14.

Figure 16 is a similar view of the indexing mechanism but taken along the line IG-IB in Figure 14.

Figure 17 is a fragmental face or plan view of a modified form of seven day clock or time control unit employing multiple day selectors in connection with the station selector pins.

Figure 18 is an enlarged, fragmental and diametrical cross section through the clock shown in Figure 17 and illustrating the construction of one of the multiple day selectors employed therein.

Figure 19 is aface or plan view of a modified form of selector of the type used in the unit shown in Figure 17, this view' also showing a setting tool of modified form.

Figure 20 is a face view, partially broken away, showing a tuning unit operated electromagnetically.

Figure 21 is an enlarged rear elevation of the lower portion of the dial and selector assembly as employed in the tuning unit shown in Figure 20.

Fig. 22 is an enlarged cross section along the line 22-22 in Figure 21.

Figure 23 is an enlarged cross section along the line 23-23 in Figure 21.

Figure 24 is a fragmental cross section through a modified form of selector member suitable for use on the tuning unit of Figure 20, and arranged for touch tuning of the radio receiver.

Figure 25 is a diagrammatical view of a magnetic field extending circuit suitable for use with the unit of Figure 20. i

Referring now with more particularity to the drawings my invention as exemplified in Figures 1 through 10 thereof includes as its basic units the time control, time switch or clock A and the radio receiver tuning unit or tuner B. The time control or clock as it may hereinafter be termed comprises the disk-like circular dial I and the long hour hand 2 and short minute hand 3 which are journaled at the center of the dial and driven by a mechanical or electrical clock works (not shown) so that the hour hand will make one complete revolution around the dial each twenty-four hours and the minute hand will make one revolution each hour. Around the outer margin of the dial I is a scale 4 marked off in hours and fifteen minute intervals thereof and adjacent to the center of the dial is an inner scale 5 marked of! in minutes as shown.

Around the outer portion of the dial I a series of spaced, radially extended slots 6 are cut, one for each fifteen minute marking on the scale 4, and these slots traverse a series of annular, concentric contact rings or hands I which areimbedded in the dial but project through, and are exposed at, the slots 6. As one possible arrangement the dial is herein shown as made up of a face plate or disk 8 and a back plate or disk 9 both formed of insulating material and secured together by the screws III. The frontal face of the back plate 9 is then provided with a wide annular recess II and the contact rings I are imbedded or mounted in this recess and insulated from each other as will be readily evident.

The slots 6 which are formed in the face plate 8 terminate at their outer ends some distance outwardly of the outermost ring I and each slot receives a slidable station selector pin I2 which has a slidably mounted brush I3 urged by a coil spring I4 into engagement with the rings 'l as the pin is moved inwardly and outwardly in the slot. The pins, of which there are of course one for each slot 6, are slidably retained in the slots by means of the flanges I5 playing inside the slots and by the heads or caps I6 pressed on the outer ends of the pins. When the pins are moved to the outermost ends of the slots 6 they will clear the outer ring I and this is the normal or of! position of the pins. Then as the pins are moved inwardly in the slots they may each be brought into sliding electrical contact with any of the rings 1 spanned by the slots. In lieu of the spring set brush l3 each pin l2, as well as the other pins still to be described, may have a small attached leaf spring (not shown) arranged to ride the contactrings.

Inwardly of the slots 6 are an equal number of shorter slots H which span a pair or more of concentric contact rings i8 and |8w located in the back plate 3 as hereinbefore described and these slots extend inwardly beyond the innermost ring l8 so that the contact pins l9 slidably mounted in these slots may be moved into a normal of! position at the inner end of the slots out of contact with the two rings. These pins N are similar in both construction and operation to the pins |2 hereinbefore described.

In addition four or more other concentric contact rings 20, 2|, 22 and 23 are imbedded in the dial inwardly of the aforesaid rings 1, l8 and [8a. and in the same manner. Then in exactalignment and registry with the three outermost rings 2|, 22 and 23 the face plate 3 has three concentric and annular slots 25, 26 and 21 which communicate with these rings. These slots are adapted to slidably receive any of the pins l9 which may be moved inwardly from their off positions in the slots l1 through the spaced, radially extended branch slots 28. The inner ends of the slots I'l may be joined by a circular slot (not shown) so that the pins l9 may be moved into this slot and, in this way, may be moved inwardly into engagement with the four contact rings 20, 2|, 22 and 23 as described. The innermost ring 20 is rigidly and electrically connected to fixed contact studs 23 which project through the dial at the inner scale 5 and are located at the quarter hours as indicated on that scale.

For convenience in description the contact rings l8 and |8a are hereinafter termed the motor and bell circuit rings, the rings 2 I, 22 and 23 the call system rings and the innermost ring 20' the feeder or main contact ring.

Cooperating with the contact pins |2 the long hour hand.2 travels over, or outside, of the short minute hand 3 and, whilebeing spaced sufllciently from the dial face to clear the inner pins I9, is inset at the point 30 so that the outer portion of the hand will have a wiping contact with the pins I2 as it rotates over the dial. This outer contacting portion ofthe hand 2 spans all the rings 1 but it will be noted that the hand will" not engage the pins when they are in their "olT positions. To aiiord only a momentary wiping cont-act with the pins the outer portion of the hand 2 is depressed along a medial line into a wide V-shaped cross section in the manner best shown in Figure 4.

Inwardly of this V-shaped portion the hour hand is provided with a laterally widened contact portion or web 3| which spans the rings i8 and l3a and which will contact and bridge any adjacent pair of the pins l9 when same are located in engagement with either of these rings. This widened portion 3| of the hour hand may be integrally formed with the hand or it may be removably and adjustably attached thereto if so desired. This latter arrangement would allow the part 3| to be adjusted to span and electrically engage any desired number of the pins I9 or to engage these pins in any position. This would, of course, require that the part 3| be adjustable both laterally and longitudinally on the hand which would be perfectly feasible.

The short minute hand 3 is similarly formed into a V-shaped section at its outer end and is of such length that it will span all four of the inner rings 20, 2|, 22 and 23 and make wipin contact with the pins I! located therein. This hand will also make contact each quarter hour with the contact studs 23.

The foregoing completes the time control assembly and it will be readily evident that as the clock hands 2 and 3 rotate over the clock face they will engage any desired combinations of the various contact pins and by so doing close circuits to the contact rings with which these pins are in engagement. Also it will be understood. that the contacts are made and the circuits closed at any desired fifteen minute intervals except at the slots 26, 23 and 21 where the minute hand 3 may be caused to contact pins therein at minute intervals if so desired. The purpose, function and operation of all these various contact elements will be fully described in the course of this specification.

As herein shown and described the contact rings 1 are eleven in number but. it is to be understood that any desired number may be used according to the number of circuits it is desired to control. For convenience in the explanation of the operation of the device these rings 1 are referred to more specifically by the reference numerals la, 1b, 10, Id, 1e, if, lg, 1h, Ii, 1 and He, the innermost ring being Ia and the outermost-1k. These two rings Ia and lie are also referred to more specifically as the phonograph starting ring and the stop" ring respectively therefore leaving nine intervening rings which are termed the station selector rings and permit of the tuning of nine separate stations in the receiver.

The tuning unit shown in Figures 5 through 10 comprises the three main. elements 32, 33 and 34 termed respectively the dial, the motor control disk and the tuning motor. The dial 32 is mounted in fixed position and in any suitable manner on the radio receiver chassis C and, like the clock dial hereinbefore described, is of circular disk-like form made up of a frontal or face plate 35 and a back plate 36 both of insulating material and held together by screws 31. The shaft 33 from the tuning condensers D of the receiver extends forwardly through this dial 32 and carries a pointer E which plays over three concentric and arcuate scales 39, 40 and 4| de- 1 marked on the face of the dial. The tuning unit is herein shown and described as for use on a three band receiver which tunes to the broadcast band and two short or medium wave bands, all with the same tuning condensers D, and for this purpose the three separate scales 39, 40 and 4| are provided and separately calibrated. Adjacent each scale and coextensive therewith are formed three concentric arcuate slots 42, 43 and 44 cut entirely through the face plate 35 and registering with wider slots 42a, 43a and 44a cut in the back plate 36. Station selector pins or slides 45 are slidably mounted in the slots and at their outer ends have the widened heads or buttons 46 which slide freely over the face of the dial and over the scales demarked thereon. At their inner ends these pins 45 carry the spring set brushes 41 normally urged rearwardly by the coil springs 48 in the manner clearly shown,

A- plurality of station selector feeder rings are imbedded in the back of the dial 32 adjacent to the slots 42, 43 and 44 and these rings are coextensive with the slots and arranged concentrically about the center of the dial. The rings 49 correspond in number and position with the aforesaid selector ring f, H, and ii on the clock dial and are correspondingly numbered on the drawings as 49b, 49c, 49d, 49e, 491', 49g, 49h, 491' and 49 i. In the assembly shown it is contemplated that five stations will be tuned in the broadcast band and two stations each in the two short wave bands. For this purpose then the five outer rings 437', 43:, 49h, 43g and 49! are located immediately adjacent the outer slot 42 and five of the selector pins 45 are placed in this slot. Each of these five pins 45 then carries a flat spring contact strip 50 which engages a separate one of these five rings as the pin is moved around in the slot. The two inner slots 43 and 44 are each adjacent a pair of the remaining rings 49b, 49c, 49d, and 49a and each slot contains two pins 45 which carry contact strips 53 engaging a separate one of these rings. This arrangement of the rings and the pins 45 is clearly shown in Figure 9.

The motor control disk 33 is also made of insulating material and is secured by its hub to the condenser shaft 33 to turn therewith at the rear of and spaced some distance from the dial 32. Mounted on the frontal face of this disk 33 are three annular contact strips 52, I3 and '4 arranged in spaced concentric relation around the outer portion of" the disk. These strips are mounted by screws 55, are each spaced from the other as indicated at 56, and each have a radially extending notch 3! cut at their outer edge portions leaving gaps at these points. The notches 51 are arranged in radial alignment and the strips themselves are so located that the brushes of the pins 45 in the outer slot 42 will ride the outer marginal portion of the outer strip 52, the pins in the center slot 43 will ride the outer marginal portion of the center strip 53 and the pins in the inner slot 44 will ride the outer marginal portion of the inner strip 54. Thus as the disk 33 rotates the pins will pass across the gaps formed by the notches 5'! as will be understood.

Inwardly of the strips 52, 53 and 54 a flat annular ring 53 is secured concentrically to the disk 33 and carries a brush 63 turned outwardly in radial alignment with the notches 51.

The disk 33 thus constructed is rotated together with the condensers D by the motor 34 through the operation of a cable 6| trained over a pulley 62 on the motor and over a drum 63 fixed on the condenser shaft 38. In lieu of this cable drive any other suitable drive may be employed and provision may be made in any well known manner for manual control of the condensers if desired.

A bracket 64 is supported on the chassis C and carries an insulating saddle 65 on which is mounted the current control band 66. This band stands edgewise to the disk 33 and is concentric therewith in such manner that the aforesaid brush 60 will ride the inner periphery of the band and make electrical contact between the band and the ring 58. This band 66 is parted so as to leave a gap 61 which is located in a radial plane just beyond one end of the scales on the dial 32 or, in other words, in a position where the brush 60 may move into this gap when the condensers D are moved to the extreme end of their range.

- This is the "oif position of the radio current controlling elements. Located in this gap 61 is a short contact point 68 which is called the phonograph starting contact and is insulated from the band 36. The screw 63 holds this contact in place on the saddle 65. An input or main feeder brush II is secured to the saddle 65 at its center, lower portion and the brush plunger II thereof is turned rearwardly so as to rice the face of the ring 53.

A brush block 12 of insulating material is also located on the chassis C forwardly of the disk 33 and carries three spaced band switching brushes l3, l4, and II which are so positioned in the block that they will ride the faces of the strips 52, I3 and 34 respectively and will engage these strips toward their inner margins so as to clear the notches I! as the disk rotates. Also mounted in the block I2 are the stop" or circuit breaking brush l3 and the phonograph starting brush II which are located respectively in radial alignment with the gap 31 and the contact point 33. These brushes l3. and H ride the outer marginal portion of the outermost contact strip 32.

The operating shaft of a conventional three band, or three position, band switch is indicated at I3 and in accordance with this invention this shaft is provided with a radially extended armature 33. Arranged in radially spaced relationship around the shaft 13 are three electromagnets 3|, 32 and 33 which are so disposed that as the one numbered 3| is energized the switch will be rotated to the broadcast band" position, as 32 is energized the switch will be turned to medium wave band" position and as 33 is energized the switch will be moved to the short wave band" position.

The foregoing completes the construction of the basic units of the invention and the necessary wiring will now be described. Referring first to the time control as shown in Figure 1 at 34 is shown the source of electrical energy for the control and tuning system as a whole and one terminal thereof is connected by a wire 33 to the main feeder ring 23 on the time control dial. The other side of this input circuit is carried by the wire 33 to the tuning motor 34. From the motor then a wire 31 leads to the common terminal 33 of the band switching electromagnets ll, 32 and 33 and from these electromagnets separate wires 33, 33 and 3| lead to the brushes l3, l4 and 13 respectively. Wires 82b, 32c, 32d, 32a, 331, 32g, 32h, 331', and 927 connect the station selector rings 1b, 1c, 1d, 'ie, if, la, In, H, and 11' to the corresponding rings 43b, 49c, 43d, 43c, 491, 43g, 43h, 43i and 437' and wires 92a and 32k connect the rings la and lie to the brushes l6 and 11 respectively. The source of primary current for the radio receiver R is indicated at 33 and a wire 33a leads directly therefrom to the radio receiver while another, 94, leads to the main feeder brush 10. A wire 95 then leads back from the band 36 to the radio receiver R. The source of primary current (this may be the same as the supply for the radio receiver) for the phonograph P is indicated at 96 and one wire 91 leads directly to the phonograph while another, 93, leads to the contact point 68. The circuit is completed by a wire 99 from the feeder brush ill back to the phonograph. This completes the wiring of the radio receiver tuning and phonograph control circuits and the function of the remaining wires and contact elements will be hereinafter fully described. For the sake of clarity the wiring is all shown in dot-dash lines in the drawings.

In describing the operation of the device let it first be assumed that the selector rings 1], 19, in, ii and 11' represent the brodcasting stations KF'I, WSB, KDKA. KMOX and WLO respectively and the remaining rings 1b, 1c, 1d and 1e represent certain stations in the medium and short wave bands respectively. The station selector pins 46 are then moved on the dial the tuning unit until the pin having contact with the ring 48h (connected to ring 1h) is opposite the, dial reading of station KDKA '(Fig. 5) and the other pins opposite the desired stations on the dial. Then supposing that it is desired to listen to KDKA. at 7:45 P. M., KMOX at 8:15 P. M., KFI at 8:30 P. M., a short wave station at 9:00 P. M., KDKA again at 9:30 P. M. and to turn of! the radio at 10:00 P. M. For this setup of stations the selector pins 12 are arranged as shown in Figures 1 and 2, the pin at 7:45 P. M. on the clock scale 4 being moved inwardly, to the ring 1h, the pin at 8:15 P. M. being moved inwardly to the ring 11', the pin at 8:30 P. M. being moved to the ring 1 the ring at 9:00 P. M. being moved to the ring 10, the pin at 9:30 P. M. being also moved to the ring 1h and the pin at 10:00 P. M. being moved to the stop-ring 1k.

Now as the hour hand 2 reaches the 7:45P. M. position it will make a momentary contact with the pin l2 in contact with the ring 1h and at the same time the minute hand 3 will make contact with the stud 29 at the forty-five minute marking on the clock scale 5. Figure 1 illustrates the parts just previous to this action. The circuit is now closed from the source of current 84 through the wire 85 to the ring and then through the stud 29, minute hand 3, hour hand 2, wire 92d, ring 49h, selector pin 46 (at position KDKA), strip 52 and brush 13 to the electromagnet 81. The circuit is completed through this electromagnet and the tuning motor 34 to the wire 86 leading back to the source 64. Closing of the circuit in this way energizes the electromagnet 8i moving the band switch to the broadcast band position (or retaining it there. if already at that position) and at the same time starts the motor 34. This action turns the condensers D and the motor control disk 33 and continues the rotation until the notch 51 in the strip 52 moves beneath the brush 41 in the pin 46 set to KDKA. At this point the circuit to the motor is opened and it immediately stops but the notch 51 is so indexed relative to the condensers D, and the pin 46 is so located, that the motor stops with the condensers tuned to the frequency of KDKA. The primary circuit to the radio receiver R is closed through the wires 93a, 94, and 95 and through the brush 10 and ring 58 so that the radio receiver current is turned on and the set put in operation as it is tuned to KDKA. Previous to being tuned to KDKA, and as will be v in and the notch 61 moves under the pin 46 set hereinafter made apparent, the primary current to the radio receiver has been disconnected. Having in this manner been tuned to station KDKA the radio receiver continues to play until the hour hand 2 reaches the position at 8:15 P. M. whereupon it makes contact with the pin I 2 at the ring 12' and the circuit to the pin 46 opposite KMOX on the tuner dial is closed. This pin is in engagement with the strip 52 and again closes the circuit to the electromagnet 8| and the motor 34, thus rotating the condensers to a new setting at which the notch 51 moves under this new pin 46 and breaks the circuit at the position at which station KMOX is tuned in. This situation continues until the hour hand reaches the pin 12 at 8:30 p. m. where the circuit is again made to the motor and causes the same to rotate in the same manner until station KFI is tuned at KFI on the tuner dial. For the next half hour station KF'I remains tuned in but as the hour hand reaches 9:00 p. m. it makes contact with the pin I! at the ring 10. At this point the circuit is closed to one of the pins 46 in the slot 44 and through this pin to the strip 54, through the brush 15 to the electromagnet 83 to the motor 34. The electromagnet 83 being thus energized attracts the armature and moves the band switch to "short wave position and the motor turns the condensers D and disk 33 until the notch 51 in strip 54 comes to rest beneath the pin in the slot 44. The selected short wave station is thus tuned in and remains so until the hour hand 2 comes to 9:30 p. m. whereat it contacts a pin I 2 at ring 171. again and closes the circuit to the pin 46 at KDKA. This closes the circuit through the brush 15 again, restores the band switch to broadcast band position and retunes the receiver to KDKA. This continues until 10100 p. m. where the hour hand engages the pin l2 at the stop" ring 1k. The circuit is then completed through the brush 16, to the strip 52 and the motor rotates the disk 33 until the brush 60 reaches the gap 61 in the band 66. This opens the circuit to the radio receiver R and turns ofi the entire system. This is the normal "stop" or off position of the parts and is the one from which the operation starts when the device is initially set up and the stations selected for tuning.

If it is desired to play the phonograph at any time a pin I2, or pins, at the desired time indicated. on the clock scale 4 is moved inwardly until it contacts the ring 1a. Then as the hour hand strikes this pin it will close a circuit to the brush 11 and the motor,34 will rotate the disk 33 until the brush 60 engages the contact point 68. This closes the primary circuit to the phonograph and it plays until the hour hand strikes a stop pin in contact with the ring 1k whereupon the motor again moves the brush to off position in the gap 61.

A desirable feature would be the inclusion of a circuit breaker by means oiwhich the receiver could be deadened while being tuned thus preventing disturbing noises which might be caused by the opening and closing of the various circuits. A simple solution would be the arranging of an electromagnet or relay so that it would be energized each time a circuit is closed to the tuning unit and connecting this relay in the radio receiver supply circuit so that that circuit would be broken while the relay is energized. This is shown diagrammatically in Figure 6 wherein the relay I25 is in series with the motor circuit and the controlled contacts of the relay are indicated as connected to short the voice coil I26 of the loud speaker I21. This is, of course, but one of the possible circuits and but one of the possible ways of killing the receiver to prevent noise between stations.

It may be here noted that thecontact strips 52, 53 and 54 may be stacked, one on the other, instead of disposed in the same plane as shown in the drawings and the contact pins 45 in this case would be arranged to ride the peripheries of the strips instead of the faces thereof. This would permit a compact assembly and one which would be suitable for selecting a greater number of stations. Another readily carried out modification would be the reversal of the assembly described so that the strips 52, 53 and 54 could be rotated to various positions to select the stopping points for the condensers and the pins 45 would in this case be stationary. The stacked assembly of the strips would be especially applicable in this assembly.

It is thought that further details of the operation will be apparent without further description herein. It will be readily apparent that any selected stations indicated by the pins 46 may b tuned in at any desired fifteen minute intervals and that once the selection is made the same sta tions will be tuned in at the same time day after day without any further attention. Also it will be apparent that the operation is entirely automatic once the initial selection is made and that no auxiliary adjustments whatever are needed for controlling the primary current of the receiver or the phonograph. For convenience in selecting the stations to be tuned in, the dials of both the time control and the tuning unit may be appropriately marked and calibrated. As

one example of such marking the positions on the time control dial corresponding to the various rings I may be numbered and the selector pins 46 given corresponding numbers thus making it possible by cross reference between the two to conveniently set up any combination of stations to be tuned in. Inasmuch as the selector pins are movable to any part of the tuning ranges or the receiver it is obviously possible to select anycombination of stations within the range of the receiver.

An auxiliary unit F is provided for manual control of the tuning unit and as shown this consists of a multi-point switch I having separate switch points IOIa, IOIb, IOIc, IOId, IOIe,

v IOIf, IOIg, IOIh, IOIi, IOIj and IOIk connected to the corresponding wires 92a, 92b, 92c, 92d, 92e, 92f, 92g, 82h, 922', 921 and 92k as clearly evident in Figure 5. There are also provided spaced shorting switch points I02I02a. A switch arm IMis journaled on the switch and may be rotated thereon to have a wiping contact with any of the various switch points. A source of operating current I is provided and one side thereof connects by wire I06 to the arm I04 while the other connects by wire I01 to the motor 34 at the same point as the wire 86. Normally the arm I04 rests on the switch points l02--I02a. and in this position the unit F has no effect whatever on the operation of the system as a whole as described. Now should the operator desire to tune in any station represented by the selector pins 48 on the tuning unit he simply rotates the switch arm I04 to the proper switch point IOI whereupon a circuit is closed from the current source I05 to the selected pin 46 and the tuning unit operates exactly as hereinbefore described to tune the receiver to the desired station. To turn off the receiver the arm I04 is turned so that it bridges the point IN a which closes the circuit to the stop brush I8 causing the motor to turn the disk to the position at which the primary circuit to the receiver is broken. To start the phonograph the arm is turned to the point IOIk closing the circuit to the phonograph starting brush TI. The shorting points I02--I02a. are respectively connected to the wire 86 and the wire I01 so that the switch unit F is effectively by-passed when the switch arm is in this position.

The time control unit A also serves as a very effective call or signal system control and for this purpose two bells H0 and HI, a buzzer II2, a motor H3, and two sources of operating current H4 and H5 therefor are shown in Figure 1. Wires IIS and III connect the motor H3 and the current source II4 to the rings I8 and 2I and as the minute hand I rotates it will bridge any radially aligned pairs of the pins I! which may be located in engagement with these rin s and so will start and stop the motor H3 at any desired times. The bell H0 and current source II! are connected by wires II! and II! to the rings Na and 23 so that the minute hand will close the circuit to this bell at any times selected by positioning of the pins IS in engagement with these rings. The bell III- is controlled and energized from the current source 84 by the pins I0 set in engagement with the rings I8 and bridged by the minute hand. The buzzer I I2 is energized from another current source I20 through wires I 2| and I22 leading to the ring 22 and to the minute hand 3. By this arrangement the buzzer may be sounded at any intervals selected by locating the pins I9 in contact with the ring 22. Chimes I23 are also provided and are connected by the wire I22 and another wire I24 to the minute hand and current source 84 in such manner that they will be sounded each quarter hour by engagement of the minute hand with the studs 29. It will be apparent that great flexibility in the operation or the various signals may be obtained by the arrangement of the pins and contact rings as described and also that the widened portion 3| oi the hour hand 2 may also be used to close certain of the signalling circuits so that several circuits may be simultaneously controlled as may be desired. 01' course any other combination of signals may be used in lieu of the bells, buzzer, motor and chimes herein described. The possible circuit variations for the signalling or call system application of the control unit are in fact so numerous as to defy adequate description herein. It may be noted, however, that no matter what type of signal is controlled it is possible to actuate the signal at any minute interval of the day since the pins It may be disposed in any number and combination in the slots 25, 26 and 21 for this purpose. Especially is this true it the slots I1 carrying these pins ID are, as hereinbefore stated, joined at their inner ends by a circular slot. While a number of separate sources of current supply are shown, and they are shown as being batteries, it is to be understood that several of these sources may be combined and also that transformers or any other available current supplies may be used.

Figure 11 illustrates a modified form of station selector pin and assembly wherein the pin 45a is slidable axially in the slot 42a so that it may be pushed inwardly by hand at any time. This action brings the point I20 on the head of the pin into contact with a contact strip I29 paralleling the slot 42a and, this strip being connected by wire I30 to the tuner current supply 84, this action closes the circuit to the strip 52 independently of the clock or time control mechanism. As a result the motor 34 and other controlled parts are energized and the receiver is tuned until the strip notch 51 moves beneath the pin and opens the circuit. At this time the receiver will be tuned to the station corresponding to the location of the pin a in the slot 42a as will be understood. This permits instant touch tuning" of the receiver to the desired station independently of the time control unit and without in any way interfering therewith. Of course the same arrangement may be used for any, or all, of the pins 45 and they are in each case provided with the hereinbefore described brushes and strips (shown at 41a and 50a) for engaging the strips 52, 53 or 54 and the various rings 49. In .lieu of these brushes the selector ;pins may also have small attached contact springs (not shown) as described above and with reference to the pins I2 and I9.

The time controlunit as hereinbefore described aifords control of the tuner, and signalling system, only from day to day. In some Installations it may be desirable to employ a control unit over an entire week. Inasmuch as radio programs are usually the same from week to week, that is, the same program isscheduled for the same time each day of the week a control unit of this kind would then enable the user to select the desired programs for each day of the week and they would be tuned in at the proper time each week thereafter without any further attention.

A time control unit for this purpose is illustrated in Figures 12, 13, 14, 15 and 16 and will now be described in detail. The clock dial Ia is circular and bears the hour scale 4a divided into twentyour hourly periods and subdivided into fifteen minute intervals of the hours, and an hour hand 2a playing over this scale and making one complete revolution around the dial each day. There is also a minute scale 5a, divided into five minute intervals of the hour and a minute hand 3a plays over this scale and makes one revolution each hour of the day. A clock mechanism I3I of any conventional form operates these hands 2a and 3a and also actuates a day indicating hand I32 which plays over the scale I33 and indicates the day of the week as will be readily evident. These hands are all electrically connected and driven by the shaft I34. The dial Ia is of insulating material and v is considerably larger in diameter than the clock per se, thus providing a space around the clock for the accommodation of the station selector mechanism now to be described. It will also be noted that another hourly scale 4aa is provided around the extreme periphery of the dial to facilitate the location of the proper selector parts as will presently appear.

Mounted beneath, or behind, the extended marginal portion of the dial Ia, above referred to. are a plurality of station selector disks or contact plates designated generally at I35 and corresponding in number and purpose to the contact rings 1 as described with reference to the one day clock. These disks I35 are accordseparated and insulated each from the other by interposed insulating disks or spacers I33 so clear the frontal disk IBaa.

ingly given the corresponding sub-designations I35a, I351), I350, I35d. I35e, I351. I35g, I35h, I351, I357 and I35k and these disks are connected to the tuner in the same manner as the one day clock by the corresponding wires 92a, 92b. 92c, 92d, 92e, 92f, 92g, 92h, 921', 127', and 92k as shown. There is also, in the assembly shown, another disk IBaa which corresponds in purpose to the ring Illa in the one day clock and issimilarly connected to the bell III by the wire H8. In the setup as shown for both time control units and the tuning unit. the disks I35 in the order above enumerated will act as controls and feeders for the stop brush I3; for the selector pins corresponding to stations KFI. WSB, KDKA, KMOX and WLO as well as two stations in both the short and medium wave bands; for the phonograph starting brush I1 and for the bell III. For convenience sake the two stations in the medium wave band are designated Imw and Zmw while the two stations in the short wave band are designated Isw and Isw.

These disks I35 arranged as described are that an assembly in alternating layers of condoctors and insulators is thus provided. This assembly is mounted to the clock dial Ia, concentrically therewith, by means of the screws I31 or other appropriate means, the disk I35 being of course counterb'ored to clear the screws and prevent shorting the assembly.

The assembly of disks thus provided is pierced from front to back by a plurality of bores or passages shown generally at I33 and which open at both front and rear of the disks. These passages are, as indicated in Figure 12, arranged in evenly spaced, radial rows aligned with each fifteen minute interval 01' the twenty-four hour day as indicated on the scale 40, there being thus ninety-six rows in all. Each row has seven evenly spaced passages which correspond to the days of the week and are so designated at I39.

As these passages are bored through the assembled disks I35 and I35 the conducting, or station selector disks, are exposed to the interior of the passages as will be readily evident. Metallic collars or sleeves I40 are pressed in the frontal openings of the passages I38 and are coextensive with the thickness of the dial Ia but collars I40 there is a contact strip or tongue I4I extended rearwardly through the passages and these strips all extend a short distance beyond the rearmost disk I36 providing a contact point designated Illa. The strips I are in all cases spaced from the adjacent walls of the passages I38 so that they make no contact with the disks I35.

A station selector pin or plunger Ila is provided for each of the passages I38 and these take the form here of elongated metal shafts adapted to fit slidably through the bores of the collars I40 and, when inserted fully into the passages, to extend throughout the length thereof and to project forwardly a short distance from the dial face. The pins make electrical contact with the collars I40 and with the contact points I4Ia and also are provided at their inner or rear ends with small contact brushes I42 which are adapted to make electrical connection with the selector discs I35 as the pins are pulled outwardly from the passages. Normally the brushes rest on the rearmost insulating disk I36; this being the off position of the pins, but by pulling the pins outwardly the brushes may be brought into contact with any desired one of the selector disks I35 as will be readily understood. For purposes of exemplification the inner pin I2a in Figure 14, corresponding to Sunday, is shown as adjusted to contact the disk I35e, the next pin (Monday) is in ofi" position, the next (Tuesday) is in stop position, the next (Wednesday) is in off position, the next (Thursday) is in contact with disk I35e, and the remaining two pins (Friday and Saturday) are also in off position. These and another settings of the pins I2a are conveniently indicated to the operator by the calibrations I43 on the sides of the pins as shown. The exposed frontal ends of the pins are provided with heads I44 for convenience in operation.

An auxiliary hour hand I45 is secured to the shaft I34 and extends radially therefrom out be hind the disks I35 and I36 in spaced relation to the inner contact points I 4Ia. This hand I45 takes the form of a shaft or rod as shown and carries a clutch head I46 and an indexing From each of these roller I41. Both these parts have the mating angularly faced notches I48 which are seven in number and allow the roller to be rotated on the shaft in one direction only and in seven steps. The notches I48 are held in engagement by a small spring I49 at the outer end of the shaft which allows the small axial displacement of the roller necessary to allow the rotationthereof. Seven indexing ribs I50 are extended from the roller I41 in equally spaced relation and are adapted to be engaged one at a time by the index finger II which is secured to the clock back I52 and extended into the path of the said ribs as the hand I45 is revolved by the clock mechanism I3I. Thus the roller will be turned one-seventh of a complete revolution each day. Seven contact wings I53 are extended radially from the roller I41, one behind each of the seven' rows of passages I38, and these wings are disposed in even radial spacing but are distributed along the length of the roller in an even spiral as shown.

The purpose of the indexing mechanism above described is to bring a separate one o! the wings I53 into position to engage the'contact fingers I4Ia each day and to ensure that the roller I41 will not contact more than one annular series of these points I4Ia each day. As shown in Figure 14 the uppermost wing I5! is making contact with the "Sunday series of selectors and it will be readily evident that the other wings will be moved progressively into position to engage the "Monday and succeeding series of the selectors as the indexing mechanism operates.

A contact ring I54 is secured to the rear of the dial Ia, inside the confines of the selector disk structure, and has four contact studs I55 located at equally spaced positions corresponding to the quarter hours as indicated by the minute scale 5a. An auxiliary minute hand I58 is provided behind the dial and is adapted to engage these studs I55 in succession as the minute hand 3a reaches the quarter hours. This ring I54 is connected as shown to the main current supply, as 84a, and each quarter hour a circuit will be completed from 84a to the roller I41 and to such of the contact points I4Ia as the roller wings I53 may engage. The wire 85a carries the return side of the circuit from supply 84a to the tuning unit.

In operation the stations to be tuned are selected for each time of each day or the week by adjustment of the selector pins I2a and then as the roller I41 revolves (with the hour hand) it will carry the current supply circuit to the disks I35 with which the pins are in contact. This of course operates the tuning unit in exactly the same manner as hereinbefore described in detail for the one day unit. To stop the receiver at the desired time the proper pin is engaged with the disk I35a, to operate the phonograph at any time the proper pin is engaged with disk I35k and to ring the bell III the pin is engaged with disk I8aa.

For convenience in setting the pins Ila to the proper positions in the passages I38 a carrier rod I51 may be journaled at the center (or outer periphery) of the clock provided with a slidable block I58 which has extended shoulders I59 of such length and in such spacing that one, two or any combination of the pins IZa may be simultaneously adjusted, see Figure 13. Also a shorter block I58a may be used for adjusting the pins one at a time and may have a hook I60 for drawing the pins outwardly from the passages. Either of these blocks may be removed from the carrier rod I51 and used alone ii. desired. Another modification which would readily suggest itself would be the substitution of pistons (not shown) for the long pins I2a and the adjustment of these in the passages by means of a small piston rod (also not shown).

Instead 01! using a separate passage and selector member for each fifteen minute interval 0! each day 01 the week as described a single selector passage may be provided for each fifteen minute interval only as indicated at I381) in Figures 17 and 18. This assembiy'utilizes the same clock and stacked disks as the first described seven day control unit and as indicated at lb, I353: and I38b. However, a tubular, elongated sleeve or cylinder ISI is mounted in each passage I381) and is provided with seven longitudinally extended and radially spaced slots I52 which correspond to the days of the week and are so designated by the markings applied to the collars I4Ilb as shown in Figure 17. In each of these slots I5! 9. contact pin I2b is slidably mounted and carries a spring brush I42b which will contact the disks I35: as the pins are adjusted along the length of the slots. The rear ends of the cylinders I8I extend and carry seven separate contact studs I which are electrically connected to leads I88 extended along the margins 01 the slots I62 to contact the pins I21), and these studs are contacted by the auxiliary hour hand I451) as it revolves and the circuit will thus be closed to any of the disks I352: with which the brushes I421) may be in Contact. The hour hand I45b carries the indexing roller I41b which is indexed daily as hereinbetore described and thus brings the proper contact wings I531) into engagement with the studs I85, this in such manner that the studs are engaged in order from clay to day to carry the current to the proper pins I2b. This is clearly shown in Figure 18. The cylinders Ill are made or insulating material in order to Isolate the pins I2b from each other and the studs I35 are arranged in rows to provide enough clearance between studs in order to allow them to be contacted separately each day. The seven pins I2b in each cylinder may be adjusted to contact any of the disks as will be evident and will close the circuit to the selected station (or signal) controlling parts of the tuning unit. It is thus possible to set up any desired combination of stations to be tuned at any fifteen minute interval of any day of the week by suitable adjustment of the pins IZb in the cylinders.

For convenience in adjusting the pins I2b in their slots I 62 a tool I63 is provided and comprises a tubular handle I34 which is adapted to fit slidably down over a pin I85 which extends centrally out through the cylinder I6I. This handle carries a radially extended finger I 68 at its inner extremity which may be engaged with any one of the pins I21) to move the same along its slot. The handle is calibrated as at I431) to indicate the position 0! the pin as it is adjusted. As an alternative the slots and pins may be more closely spaced as in Figure 19 and the finger I8ia may have a plurality oi! projections I81 for moving and adjusting one or more pins at the same time. In either case the tool may be removable for use in order on all the selector members or, if so desired, a tool may be permanently provided for each member.

As illustrated in Figure 1'1 the selector members are arranged in staggered relation with the inner annular row in radial alignment with control thereof, the circuit being completed I the hours on the clock scale, the next outer row in radial alignment with the fifteen minute period of each hour, the next in alignment with the half hour period of each hour and the outer row in alignment with the forty-five minute period of each hour. This permits a somewhat more compact assembly and the selector members of the other clocks previously described might well be similarly arranged. It should be also evident that the various disks could be engaged as well as their outer peripheral margins by arranging the selector pins in a radial direction.

The one day clock could also be arranged with slidable pins engaging through alternate layers of insulation and conductor instead of using the concentric rings and pins as described and this would require but one pin'for each fifteen minute interval of the day. It will be evident that other combinations of the selector mechanisms may be worked out also.

In lieu of the motor operated tuning unit as previously described I may employ an electromagnetically actuated tuning unit which will now be described. Referring to Figures 20, 21, 22 and 23 particularly a tuning unit of this kind is shown, the same comprising the tuner dial 32d over which travels the pointer E to indicate the settings for different stations on the scales on the dial as will be understood. These scales are designated 39d, 40d and lid. The dial further has three concentric slots 42d, 43d and d for the slidable reception of the station selector members 45d and has a plurality of concentric station selector rings 49 imbedded in its rear face. These rings 49 are arranged in the same manner, and serve the same purpose, as the rings 49 in the motor tuner previously described and are connected in the same way to the wires 92 leading to the time control unit. The shaft 38d which carries the pointer E is extended from the receiver condensers (not shown 'here) and also carries an armature or arm I68 of ferrous metal which travels with the condensers and is spaced rearwardly from the dial 32d. The dial itself is. of course, fixed immovably on the chassis. The receiver current control band is, in this case, a sector-like strip 66d secured to the rear of the dial and the phonograph starting contact 68d is similarly mounted adjacent to one end of this strip 66d. The armature I68 then carries a brush 50d which will play over the strip 66d and the contact 68d and carry current from the receiver and phonograph primary current sources 93d and 96d. Wires 95d and 98d then run from the strip 66d and contact 68d to the receiver R and phonograph P completing the circuit. Thus as the armature reaches its furtherest clockwise position the receiver will be off but as the armature moves in a counter clockwise direction the brush GM will make contact with the strip 66d and close the circuit to the receiver. This movement of course tunes the receiver across its entire frequency range as will be understood. At the extreme end of this movement the brush 60d makes contact with the contact 68d and operates the phonograph P.

This movement of the armature I68 is brought about by the stopping electromagnet I69 and phonograph starting electromagnet I10 which are mounted on the rear of the dial 32d at the proper radial positions to attract the armature and cause it to come to rest at the extremes of its oscillatory movement behind the dial. These electroma nets I69 and H are connected at 920 and 92k to the time control unit to be energized under through wire 86 as shown.

The band switch 19d is or exactly the same construction as the one nereinbefore described and includes the three electromagnets lild, lid and sea connected by their common lead Old to the wire at and being separately connected by wires tad, Ulla and ind to three feeder contact rings Ill, m and H3 which are imbedded in the rear OI the dial face concentric with, but spaced from, the selector rings 48.

The station selectors, per se, here take the form of small electromagnets I14 enclosed in rectangular cases no and having the forwardly extended pins ied which are slidably mounted through the slots 42d, 43d and d. The ends of the cases H5 are slidably fitted into laterally enlarged portions 116 at the rear of the slots and the plnsthemselves are preferably, though not necessarily, threaded into the cases so that the pins may be locked in adjusted positions in the slots simply by screwing them tight. Like the aforesaid pins 45 these selectors carry small contact springs 50d which slidably engage the rings 49 and make contact therewith. A separate spring of course is provided for each selector and engages a separate one of these rings. These springs are connected to one terminal of the electromagnets I14 and the other terminal of each electromagnet is connected to a feeder contact arm I" which extends radially to engage and ride one of the feeder rings lll, H2 or III. The electromagnets in the outermost slot 42d (broadcast band) ride the outer contact ring Ill connected to switch 19d at electromagnet Qld; the electromagnets in the center slot 43d are connected to ring I12 (medium wave band) and to electromagnet 82d, and the, electromagnets in the innermost slot d (short wave band) are connected to the ring I13 and electromagnet 83d. Thus the broadcast band selector electromagnets will be energized as the band switch is moved to broadcast band position and the medium and short wave selectors will be energized only when the band switch is set to the corresponding bands.

In operation then the armature I68 may be moved to any position in its range by energizing the selector electromagnets I14 across the ends of which the armature swings. Then by adjusting the selectors to the proper positions in the slots 42d, 43d and Nd the condensers of the receiver may be tuned to any selected station in any wave band. The energization of the electromagnets is directly under control of the time control unit (either the one or seven day types) and the opera ation of this tuning unit corresponds in other details to that of the motor unit hereinbefore described.

Instant touch or press tuning may also be carried out with this tuner as indicated in Figure 24, the selector pin 45e being slidable in an axial direction to engage the contact |28e with the feeder band |29e to energize the electromagnet I He and attract the armature l68e to the. selected station position.

11' it should be desired to use relatively weak electromagnets for the selectors and dinlculty should be encountered in attracting the armature by these selectors, the circuit shown in Figure 25 may be employed. In this assembly the rings 49', Ill, I12 and I13 as well as the band switch electromagnets Bid, 82d and 83d all serve their original purposes and are connected to the wires 86 and 92 in exactly the manner previously described. Provision is then made

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