US2313653A

US2313653A - Tuning mechanism

Info

Publication number: US2313653A
Application number: US427366A
Authority: US
Inventors: Harry J Lyman; Donald H Mills; Walter H Friedrich
Original assignee: Philco Radio and Television Corp
Current assignee: Philco Radio and Television Corp
Priority date: 1942-01-19
Filing date: 1942-01-19
Publication date: 1943-03-09
Anticipated expiration: 1960-03-09

Description

March 9, 19 43. H. J. LYMAN EIAL 653 TUNING MECHANISM Filed Jan. 19, 1942 5 Sheets-Sheet l March 9, 1943. LYMAN' ET AL 2,313,653

TUNING MECHANISM Filed Jan. 19, 1942 5 Sheets-Sheet March 1943- H. J. LYMAN ETAL TUNING MECHAN ISM Filed Jan. 19, 1942 5 Sheets-Sheet 3 March9,1943. J. LYMAN HAL 2,313,653

' TUNING MECHANISM Filed Jan. 19, 1942 5 Sheets-Sheet 4 March 9, 1943. I H. J. LYMAN ET AL 313,653

TUNING MECHANI SM Filed Jan. 19, 1942 5 Sheets-Sheet 5 Patented Mar. 9, 1943 UNITED STATES PATENT OFFICE TUNING MECHANISM Harry J. Lyman, Royal Oak, and Donald H. Mills and Walter H. Friedrich, Detroit, Mich., assignors to Phllco Radio & Television Corporation, Philadelphia, Pa., a corporation of Delaware Application January 19, 1942, Serial No. 427,366

34 Claims. '(Ol. IA-

trical type that involve, for example, the substitution of circuit elements. In general, tuners of the mechanical type are less expensive to manufacture for they do not require the numerous costly coils, condensers and switches that are employed in electrical tuners. Too, tuners of the electrical .type are customarily employed with circuits employing but two tuned stages, whereas mechanical tuners generally may be used to tune as many stages as desired.

With the foregoing in mind, the principal object of the present invention is to provide a compact and unitary tuning mechanism of the mechanical type that overcomes the difliculties and disadvantages presented by prior devices of this general type, and is operable to tune as many stages as desired without materially adding to the cost or complexity of the device.

Another object of the invention is to provide a radio tuner that is capable of both manual and automatic operation with a minimum of efiort and attention on the part of the operator; and wherein the change-over from one mode of operation to the other is very readily effected.

Another object of the present invention is to provide a tuning device of the character set forth that is capable of the extremely accurate and simultaneous tuning of a number of circuit ele ments. Q

- Still another object of the invention is to p vide a tuning device of the stated type wherein backlash is eliminated under conditions of both manual and automatic tuning.

Yetanother object of the invention is to provide a tuning device as set forth wherein com.-

plete tuning accuracy is obtained without the use of costly, carefully machined parts.

A further object of the invention is to provide a tuning mechanism of the stated type wherein the automatic tuning controls are readily adjustable bythe user to condition the apparatus.- 1 to select a certain set of desired stations without" requiring the services of an exper Serviceman,

or the use of aligning instruments.

A still further object of the invention is to pro vide a tuning device embodying a novel stopcarrying member that is mounted for step-bystep rotation thereby to successively position the stops to vary the carrier frequency to which theradio setwill respond.

These and other objects of the invention and the various features and details of the construction and operation thereof are hereinafter fully set forth and described and shown in the accompanying drawings, in which:

Figure 1 isa view in perspective of a radio receiving set incorporating a tuner of the present invention;

Figure 2 is a view in perspective of a tuning mechanism embodying the present invention, a portion of the base or mounting plate thereof being broken away to better illustrate certain details of the construction and operation thereof.

'Figure 3 is a plan view of the mechanism shown in Figure 2.

Figure 4 is a plan view of a novel, rotary stop member and its associated linkage;

Figure 5 is a view similar to Figure 4, showing the relative positions of the several parts at the completion of an actuating stroke;

Figures 6 to 8 inclusive, illustrate successive positions of a portion'of the operating linkage;

Figure 9 is a diagrammatic view in plan illustrating operation of the essential parts of the mechanism for effecting automatic tuning;

Figure 10 is a view in side elevation (enlarged) of the rotary stop member;

Figure -11 is a .view in perspective looking up ward at the lower face of the pivoted sector or linkage members shown in Figures 4 and 5'; p ,Figure 12 is a diagrammatic view iii-perspective of a portion of the manual operating mechanism, a portion of which has been cut away to 1 better illustrate certain features thereof;

Figure 13 is a diagrammatic perspective view looking upward at the underside of the mechanism illustrated in Figure 12;

Figure 14 is a diagrammatic operational view in plan illustrating the essential parts of the mechanism for effecting manual tuning; and

Figures 15 and 16 are plan and perspective views respectively. of parts of the mechanism for indicating the station to which the receiving set is tuned by the mechanism of the present invention. 1

The illustrated embodiment of the invention comprises, in general, a three coillinductance tuner having a single movable carriage to which the core members oi said tuner are secured. This carriage is moved by a lever pivoted inter mediate its ends and one end of said lever is in driving relation with the carriage while the other end is arranged to be actuated by any suitable means, for example, a solenoid as in the present case. It will be clear that the lever may be actuated by other means, for example, by force applied directly by a manual control.

For the purpose of determining the extent of movement of the carriage, there is provided a rotatable member or turret which carries a'series of adjustable stops arranged in equally spaced radial relation around its periphery, and the arrangement is such that actuation of the aforesaid lever by the solenoid serves both to move the carriage and lever to one limit of their movement and also to rotate the turret member so as to bring its radial stops successively into position for engagement by said lever 'to predeterminedly position the same, suitable means being provided for urging the lever, from the limit position to which actuated, back into engagement with the particular stop then in operative position. Thus a different tuning position of the carriage is effected for each actuation of the pivoted lever.

In addition to the foregoing, the device comprises a manually operable member for effecting a simple manual control of the carriage tuning position by varying the position of a particular stop provided for the purpose on the rotary .member to condition or set-up the apparatus for the automatic selection of predetermined desired stations. Provision is also made for indicating the station to which the set may be tuned by both automatic or manual operation.

Referring now particularly to the drawings, there is illustrated in Figure 1 an automobile radio receiving set i employing a tuning device or mechanism embodying the present invention mounted as a unit in the lower central portion of the casing 2, with the various control elements disposed as shown. In the particular embodiment shown, the controls comprise a conventional "off-on volume control element 3, a pivoted switch-bar 4 for effecting automatic tuning of the set, and a manual tuning knob 5. A tuning indicator dial is shown at 6, and associated therewith is a pointer I which is caused to move transversely of the dial 6 in response to the tuning operations in a manner hereinafter more fully described.

The dial 6 is arranged to indicate the tuning position of the set under both manual and automatic conditions or operation,\ and to this end is provided with suitable indicia,.such as, for example, the frequency designations shown thereon. It is a well recognized characteristic of inductance tuning devices that the rate of changeof frequency is not uniform for equal increments of core movement and in the present embodiment this is compensated for by the use of a non-linear scale. It should be borne in mind that such compensation may be effected in other ways, for example, by varying the design of one or more of the operating parts of the device. I! desired, the dial 8 may be of the and particularly to Figures 2 and 3 of the drawings, it will be observed that the entire mechanism is quite compact and easily handled, being mounted on a base or plate 9 which makes it possible to secure the mechanism as a unit within the radio receiver casing 2 simply by providing 'one or more suitable brackets to which the base or plate 9 may be secured.

The mechanism comprises a plurality of tuning devices ill for tuning the circuits of the receiving set to select signals of diiierent carrier frequencies. By way of example only, as it will be obvious that other tuning devices could be employed, the tuning devices iii are of the variable inductance type, each comprising a coil II and a powdered iron slug or core l2 adapted to move into and out of its coil and thereby vary its inductance. In the particular mechanism shown, three such tuning devices llare provided and of these, the central one is shown without a casing (Figure 3). The tuning devices Ill constitute components of a radio receiving circuit (terminals I3) and as this general type of radio tuning is well known, it is neither necessary to illustrate the radio circuit in detail nor to show the connection of said tuning devices thereto.

The core [2 of each tuning device I0 is connected at its forward or outer end, by means of a screw or other suitable connector element it, to a carriage i! which is mounted upon a pair of spaced bars 16 and IT for sliding movement toward and away from the tuning devices ill. These bars extend through suitable openings in said carriage and have their opposite ends suitably fastened to upstanding flanges I8 and I9 formed on the base plate 9.

As best shown in Figure 3 of the drawings, the carriage I5 is provided (at its leithand end) with a rearwardly extending leg 20 having at its extremity a flange portion 2| which is apertured to slidably receive the aforesaid bar i1. Disposed adiacent and parallel-to the bar ii is a rod 22 of smaller diameter supported at spaced points along its length by the flange is of the base plate 9 and by. the carriage flange 2|. An expansible spring 23 is mounted upon the rod 22 and this spring reacts between the fixed upstanding flange iii and novel edge and back lighted type shown and desscribed in copending application of Burton and Nichol, Serial No. 434,952, filed March 16,

the carriage flange 2i constantly to urge the carriage ii in the direction of or toward the tuning devices l0 and the cores l2 thereof into their coils ll.

Mechanism is provided for moving the carriage l5 outwardly against the action of its spring 723,

and also for effecting a step-by-step selection of various stop elements which serve to fix the position to which the carriage i5 and the connected cores i2 are actuated with respect to the coils ii of the tuning devices [0 for each tuning position of the device. Thus,-as best illustrated in Figure 16, thereis secured to the side of the leg 20 of the carriage IS a depending plate or block 24 having an opening 25 therein which is engaged Pin 38 to a link 3! and this link in turn is pivoted as at 32 to the underside of thebase-plate 3 of the device.

In the present case, actuation of the link 3| is eilected by means of a solenoid 33 having a core 34 which is drawn into the solenoid upon energization thereof. This core 34 at its outer end carries a depending finger 38 which extends through an opening in the base plate 8 and. is engaged with the link 3i through an opening 38 therein (Figure 2). The core 34 is fixedly mounted upon a rod or bar 31 which is slidably supported by a bracket 38, and a spring 38, mounted on said rod 31 and acting between said bracket 38 and a washer 49 at the outer end of the rod, operates to return the core 34 to its extended position upon deenergization of the solenoid 33.

In this connection, Figure 9,0! the drawings illustrates the relative positions of the lever 28, yoke 28, link 3i and finger 35 when the solenoid 33 is deenergized,.whereas the relative positions of these same parts when said solenoid 33 is energized are shown in Figure 4 of the drawings.

Thus, with the parts in their rest positions shown in Figure 9, energization of the solenoid 33 by depression of the switch bar 4 actuates the solenoid core 34 in the direction of the arrow with the result that its finger 35 causes the link 3| to move in a clockwise direction about its pivot 32 to the position shown in Figure 4 thereby simultaneously actuating the yoke 28 rearwardly and in turn the lever 28 in a counterclockwise direction about its pivot 21 into the relative positions shown in said Figure 4. This counterclockwise movement of the lever 23 in turn actuates the block 24 forwardly in the direction indicated by the arrow in Figure 9 thus moving the carriage I to its extreme forward limit of movement against the force of the spring 33. On the other hand, upon deenergization of the solenoid 33 the spring 39 operates to return the core 34 to its extended position and said core 34, at the same time, operates through its finger 35 to return the link 3| and yoke 28 to their rest positions shown in Figure '9, while the spring 23 operates to move the carriage l5 and its cores l2 inwardly and also to move lever 28 in a clockwise direction until an abutment 4! on the latter engages one of a plurality of stop members 42 thereby predeterminedly limiting clockwise movement of said lever 28 as well as inward movement of the carriage I5 and the cores I2 with the result that the devices III are adjusted to correspond with a particular carrier frequency.

The several stops 42 are carried by a member cr turret 43 which is rotatably mounted at the I underside of the base plate 9 by means of a central pin 43a. These stops 42 are in the form of screw elements each comprising threaded stem and knurled head portions 42a and 42b, respectively. The turret 43 is provided with a series of radially extending equally spaced apart recesses in which the stops 42 are positioned, and these each have an inner portion 44 of a size sumcient to permit of longitudinal movement therein 0! the head portions 42b of the stops, and also have a threaded outer portion 45 (see Figure 4) of re-- duced size to receive the threaded stem portions 42a of said stops, the threadnon the recess portions 45 being arranged to mesh with the threads on the said stems oi the stops so that the latter may be adjusted radially with respect to the turret 43 merely by turning the heads 42b of said stops in the appropriate direction. In order to hold the stops 42 in the recesses of the turret with the the threaded recess portions 45, there are provided relatively short lengths or spans of spring wire 48 (see Figure 10) which overlie the stems of the stops 42 and have their opposite ends engaged under suitable projections 41 spaced peripherally of the turret at points midway between the adjacent stop elements. As will be clear from any one of Figures 4, 5 and 9, each of the'screws is intended to be adjusted to project a diiferent distance from the turret, and thereby select a difierent station by varying the ultimate position of lever 28, and thence carriage l5.

1 The turret 43 is rotated step-by-step in a counterclockwise direction with respect to Figure 2 of the drawings so as to bring-the stops 42 successively into position for engagement by the aforesaid abutment M on the lever 26. Rotation of the turret in this manner is effected likewise throughactuation of the solenoid core 34 when the solenoid 33 is energized as aforesaid. To this end there is provided what may be termeda sector plate 48 and this plate 48 is mounted for pivotal movement about the aforesaid pin 32 which serves also as the pivot for the link 3 I. The

sector plate 48 is resiliently coupled to said link 3| by means of a spring 49 ofsuficient strength so that said plate 48 is actuated by movement of said link 3|.

The sector plate 48 has a generally arcuate slot 58 formed therein and this slot is constructed and arranged to engage successively a series of upstanding pins 5! formed on each of the aforesaid turret projections 41 and thereby rotate the turret 43 in a step-by-step manner as hereinafter more fully set forth and described.

Reierring now to Figures 4 to 8 of the drawings, Figure 5 shows the relation of the mechanism, including sector plate 48 and turret 43, in their rest or deenergized solenoid position (of. Figure 9), and Figure 4'shows said parts in the position to which actuated upon energization of the solenoid 33 (but before return of lever 26 agaihst stop 42), while Figures 6, '7 and 8 illustrate diagrammatically the movements that take place as the sector plate 48 moves from the rest position in Figure 5 to the position in Figure 4 In the rest position of sector plate 48 just prior to energization of the solenoid 33 shown in Figure 5, it will be observed that two of the pins 5| reside within the slot 58 and,'to avoid confusion in describing the operation thereof upon energization of the solenoid 33, these two pins will be referred to as pin 5la and pin 5lb, respectively, as indicated in Figures 4 to 8 of the drawings.

Referring now to Figure 6, the sector plate 48 has started to move in a clockwise direction about its pivot 32 in response to the pull of the solenoid 33 which is transmitted through the resilient coupling 49. At this stage of movement of the plate 48 the turret 43 has not yet moved as the slot 58 has merely moved a short distancerelative to the pin Sla without moving the latter. V Also at this stage (Figure 6) it will be seen that the other or succeeding pin 5Ib has been engaged by the base portion of the slot 50, and as rotation of the plate 48 continues it carrieswith it the said pin ilb thereby causing the turret to begin its rotary movement in a counterclockwise direction as shown in Figure 7. At this same stage (Figure 7), rotation of the turret-43, as aforesaid, causes the pin 5la to move outwardly from the slot 58 of plate 48 through an 'elevated or bridge portion 52 formed therein outwardly adjacent threads on their stems42aproperly meshed with said slot. This bridge 52 is most clearly illustrated in Figure 11 of the drawings.

In Figure 8, continued rotation of the plate 48 has moved the pin |b and turret 43 approximately one-half of the distance from the initial position shown in Figure 5 toward the position thereof at the completion of the operation shown in Figure 4. Also, it will be observed that the.

pin 5|a has now moved substantially away from the plate 48. In Figure 4 it will be observed that the sector plate 48 has carried the pin 5| b into the positionoccupied by pin 5|a prior to energization of the solenoid 33 thereby positioning the turret 43 and another of its stop elements 42 for cooperative engagement by the lever 28 which, at the same time, has been actuated to the extreme limit of its counterclockwise movement by the link 3| and yoke 28 as aforesaid. This cycle of operation, of course, is completed substantially instantaneously upon energization of the solenoid 33, and the result is a rapid stepby-step successive selection of the various stations that the radio set is conditioned to receive.

, Upon completion of the aforesaid operationcycle and deenergization of the solenoid 33, the

sector plate 48 is returned in a counterclockwise direction to the position shown in Figure 5 and V in the course of this return movementthe said plate 48 passes over the next of the pins 5| and engages the latter within its slot 58. To enable the plate 48 to pass over succeeding pins 5| upon its return movement, there is formed in the portion of the plate traversed by the pins an upwardly offset outwardly inclined ramp portion 53. This will be seen by reference to Figure 4 wherein the succeeding pin is designated 5|c.

Referring again to the spring 48 that serves to resiliently couple the sector plate 48 to the link 3|, as previously described, it is pointed out that, in addition merely to providing an actuating connection for the plate 48, this spring 48 serves three added useful purposes in the device. Thus spring 48 operates not only to reduce stresses that would otherwise occur due to the speed of movement of the solenoid core 34 and the inertia of the turret 43, and to permit the link 3| to continue its movement after the plate 48 has reached the limit of its movement until a stop lie on said link moves into engagement with the edge 48b of said sector plate 48 as shown in Figures 4 and 11, but functions also to permit the sector plate 48 to be raised somewhat out of the plane of its rotary movement to facilitate and permit the ramp portion 53 of said plate 48 to pass over the next pin 5|c and engage the latter in its slot 58 upon return movement of plate 48 in the manner previously described.

By permitting the link 3| to continue its rotation after the plate 48 has reached the limit of its travel as aforesaid, the turret and its particu-' lar stop element 42 is brought to and held in the proper operative position a moment prior to the time that the link 3| reaches its limit position and the solenoid is deenergized.

Summarizing the foregoing operation, upon energization of the solenoid 33 its core 34 is actuated inwardly and the finger 35 carried thereby moves the link 3| in a clockwise direction thereby actuating yoke 28 to move lever 28 in a clockwise direction and actuate the carriage l5 and its cores -|2 to the limit of their outward movement. This same movement of link 3| serves also to actuate sector plate 48 in a counterclockwise direction, and the slot 58 thereincooperates with one of the pins 5| to move the turret 43 and one of its stops 42 in a clockwise direction into a definite position with respect to the lever 28, so that upon deenergization of the solenoid 33 and the return of the link 3|, yoke 28 and sector 48- to their rest positions, the said turret stop 42 will be engaged by the lug 4| on the lever 25 and thereby predeterminedly limit return movement of said lever 28. Engagement of stop 42 with lug 4| also limits inward movement of the carriage l5 and its cores |2 with respect to their coils under the action of the carriage spring 23; with the result that the radio set is tuned to a signal of a particular carrier frequency.

Preferably a suitable switch (not shown) is interposed between the switch bar 4 and solenoid 33 and it is desirable that this switch be of the type that operates to mute the receiver while it is being tuned. This may be done, for example, by momentarily short-circuiting the loudspeaker and, as switches of this type are well known in the art, it is not necessary to illustrate or describe the same.

As previously stated, in addition to the automatic tuning mechanism, there is provided a manual control knob 5 operable to permit of continuous manual adjustment of the tuning devices |8 through the whole of the frequency band of the radio receiving set.

To this end the knob 5 is secured upon the outer end of a shaft 55 which is in turn flexibly connected to a shaft 58 that extends inwardly of the tuning mechanism and has a friction roller 51 of rubber orsimilarmater-ial secured on the inner end thereof as shown in Figures 3 and 12 of the drawings, the said shaft being journalled upon the base plate 8 by means of a suitably formed plate 58.

This friction roller 51 is adapted to engage the knurled head of a particular screw stop element 58 that is arranged upon and carried by the turret 43 in the same manner as the previously mentioned stop elements 42 except that the stop element 58 is disposed at an elevation slightly above that of the said stops 42 (see Figure 10). Provision 'also is made for engaging the roller 51 with the heads of the stops 42 as hereinafter set forth.

In order that the head of the screw stops 42 and 58 may be engaged by the friction roller 51, an opening 88 is provided in the base plate 8 overlying the turret 43 and the said roller 51 extends through this opening 88 as .shown in Figure 12.. Secured at one of its ends to the base plate 8 is a spring plate 8| the free end portion of which supports the shaft 58 and normally holds it at an elevation so that the friction roller 51 thereon is held in spaced relation above, and free from engagement with, the heads of the screw stops 42 but at an elevation that will permit said roller 51 to engage the head of the special stop 58 withthe required amount of pressure .to enable said stop 58 to be rotated 'and adjusted merely by, rotating the knob 5.

Adjustment of the plate 8| to this end, as well as to correct for manufacturing tolerances, may be accomplished by an adjusting screw 62 which is threaded through'said plate 8| .and arranged to bear against the underlying base plate 8.

From the foregoing it will be seen that after the turret 43 has been stepped (by energizing solenoid 33) to the position shown in Figure 5 with the special screw top 58 disposed beneath the friction roller 51 and in operative relation to the abutment 4| of lever 26, the set may be tuned manually throughout its entire frequency band by manually rotating the knob 6 in the appropriate direction. This is shown diagrammatically in Figure 14 from which it will be observed that rotation of the friction roller 51 by means oi. the knob will operate to advance or retract the manner is very easily accomplished and can be special stop 69 thus imparting a corresponding movement to the lever 26 and thereby vary the setting of the carriage l5 and the cores l2 with respect to the coils ll of the tuning devices It.

Under both manual and automatic conditions of operation backlash is eliminated, as all parts are always maintained in firm contact with each other, under the influence of the various springs. This is possible because the device is of the abutment type throughout, 1. e., the final position of the parts is always determined by each part abutting against another under the positive pressure of the springs.

As previously stated, provision i made for engaging the roller 51 with the other stops 42 in .order that the latter may be adjusted to condition the receiver to receive a predetermined desired series of stations when automatically tuned done by the owner or operator thereof without the necessity of a special servicing operation.

For providing positive visible indication of the tuning position under conditions of both automatic and manual tuning of the set, a novel mechanism is provided which is actuated through direct mechanical linkage with the carriage plate 24 that is moved by the lever 26. As shown in Figures 2, l5 and 16 of the drawings, secured to the flange IQ of base plate 9 is the vertical depending flange portion 61 of an angle member, the horizontal portion 68 of which extends inwardly and above the base plate 9 with sufilcient clearance between the two for travel of the carriage i5. Pivotally connected by a pin 69 to this portion 68 of the angle member is a bell crank iii, one arm H of which extends outwardly to the carriage block 24 and is connected thereto by a upon energization of the solenoid 33 by actuation of the switch bar 4, and to this end, as shown in Figures 12 and 13 of the drawings, the free end of the spring plate 6| is provided with spaced projecting portions 63 which engage-under a bridge plate 64 through spaced openings 65 formed therein, the bridge plate 64 being secured in upstanding relation upon the base plate 3.

Now the

shafts

55 and 56 are mounted upon the base plate 9 in such manner that when pressure is applied inwardly to the knob 6 the said shafts, as well as the friction roller 61 and plate 6|, are caused to move inwardly a short distance suflicient to engage the rearward edges of the aforesaid projections 63 against the adjacent or the drawings, these rearward edge portions of the openings 65 curve downwardly and provide cam surfaces 66 which, upon engagement thereof by the rearward edges of the plate projection 63, cause the platetl and friction roller 61 to be deflected downwardly a distance suflicient to cause saidfriction roller 61 to engage the heads of an underlying one of the stops 42 with enough pressure so that said stop 42 may be adjusted radially of the turret 43 by rotation of the knob 6 in the appropriate direction.

Thus it will be seen that each of the stops 42 may be brought into position beneath the roller 61 and the latter then engaged therewith by pressing inwardly onthe knob 5 which may then be rotated in the appropriate direction to ad just that particular stop and consequently lever 26, carriage l5 and cores I2 to the position for receiving the station desired, Upon release of pressure on the knob 6 the particular stop 42 will remain. in the position to which adjusted, and when said stop is moved by solenoid 33 into position for cooperation with the abutment 4! on lever 26 under conditions of automatic tunin the receiver will be tuned to that station.

In this connection, it is pointed out that this adjustment of the stops 42 is efiected with the receiving set in operation, and that the-lever 26 is moved by the rotation of each stop 42 until a certain desired station is heard, the spring elements 46 serving to retain the stops 42 at the positions or settings to which adjusted. Adjustment and conditioning of the receiving set in this pin 12 on said block which is slidably engaged in a slot 13 insaid arm, while the other arm #4 of said bell crank Hi extends forwardly at right angles to said arm Ii, and has its extremity bi-,

furcated longitudinally as indicated at 15.

overlying and arranged for relative sliding movement longitudinally with respect to the arm 14 of the bell crank 10 is an elongated member i6 which, at its outer end, carries the pointer i and at its inner end is provided with a longitudinal slot 18 in which the bell crank pivot pin 69 is slidably received. Also carried by and depending from the member 16 is a pin 19 which slidably engages a slot formed in the portion 68 of the angle member adjacent and along the forward edge thereof.

Thus it will be seen that as the block 24 is moved outwardly by lever 26 or inwardly by the spring 23, the bell crank 10 is caused to pivot counterclockwise or clockwise about its pin 69 I .virtue of the slotted connection thereof with the pin 69, the bifurcation 15 at the extremity of said bell crank arm I4 providing a recess or clearance for pin 19 as the latter moves through the arcuate mid-portion of its slot 80. Embracing the pin 69 and extending outwardly and engaging the arm H of the bell crank 10 at a point remote from said pin is a spring member 81 which serves to urge the edge of the slot I3 in said arm 'Il into contact with the pin 68 on the block 24 and thereby eliminate backlash resulting from too great a tolerance or looseness therebetween.

As previously stated herein the device may be equipped with a suitable switch for energizing a light (not shown) only when the mechanism is positioned for manual tuning thereof by the knob 5. As shown in Figures 4 and 5, this switch may comprise a suitably insulated spring element 82 fixed to the base plate 9 by a rivet or the like 83 and having a portion arranged to underly the lower surface of the turret 43. Secured upon the underface of the turret 43 is a grounded contact 84 positioned so as to engage the spring element 82 and close the circuit therethrough only when the special screw stop 59 is positioned for cooperation with the lever 26 in the manner aforesaid.

From the foregoing- .it' will be seen that the present invention provides a compact, unitary tuning device of the mechanical type that is capable of both automatically and manually tuning with extreme accuracy a number of elements in a radio circuit without limitation as to the number of tuned stages employed. Too, the invention .provides a novel construction and arrangement of parts whereby the automatic tuning controls can be readily and quickly adjusted by the user to condition the apparatus to select a particular set or series of stations without the necessity of having this done by an experienced serviceman, as in the past. This invention is further characterized by its complete tuning accuracy through elimination of backlash, and this has been accomplished in the present construc tion without the use of costly and precision machined parts.

While a particular embodiment of the invention has herein been illustrated and described, it is not intended that the invention be limited to such disclosure but that changes and modifications may be made therein and thereto within the scope of the annexed claims.

We claim:

1. In a tuning device for radio apparatus incorporating an adjustable tuning element, a first movable member operatively connected with said tuning element and actuable to adjustably position the same, a second movable member carrying a plurality of stops arranged for individual cooperation with said first movable member to stop the same and the tuning element at various predetermined positions, one of said stops normally being positioned to cooperate with said first movable member, mechanism for simultaneously moving the first movable member out of cooperative relation with the stops of the second movable member and for moving said second member to bring another stop into position for cooperation with said first movable member. and means operative independently of said mechanism for returning the first movable member into cooperative relation with said other stop.

2. In a tuning device for radio apparatus incorporating an adjustable tuning element, a movable member operatively connected with said tuning element and actuable to adjustably position the same, a rotary element carrying a plurality of stops arranged for individual cooperation with said movable member to stop the same and the tuning element at various predetermined positions, said stops being adjustable with respect to said rotary element and one of said stops being positioned to cooperate with said movable member, mechanism for simultaneously actuating the movable member out of cooperative relation with the stops of said rotary element and for rotating said rotary element to bring another stop into position for cooperation with said movable member, means for returning the movable member into cooperative relation with said other stop, and mechanism operable to individually adjust the stops with respect to the rotary member.

3. In a tuning device for radio apparatus incorporating an adjustable tuning element, a pivoted member having one endoperatively connected with said tuning element and actuable to adiustably position the same, a rotatable member carrying a plurality of spaced peripherally disposed stops'arranged fer individual cooperation with said pivoted member to stop the same and the tuning element at various predetermined mechanism for simultaneously actuating said pivoted member out of cooperative relation with the stops of said rotatable member and for moving the rotatable member to bring another stop into position for cooperation with the pivoted member, and means for returning said pivoted member into cooperative relation with said other stop.

4. In a tuning device for radio apparatus incorporating an adjustable tuning element, a pivoted lever having one end operatively connected with said tuning element and actuable to adjustably position the same, a rotatable disk carrying a plurality of spaced circumferentially disposed stops arranged for individual cooperation with said pivoted lever to stop the same and the tuning element at various predetermined positions, said stops being adjustable relative to the rotatable disk and one of said stops normally being positioned to cooperate with the pivoted lever, mechanism for simultaneously actuating said pivoted lever out of cooperative relation with the stops of said rotatable disk and for movin the rotatable disk to bring another stop into with said tuning element and actuable to adjustably position the same,- a member mounted for rotation adjacent said lever and. carrying a plu-. rality of stops disposed about its periphery, said stops being arranged in turn to individually co operate with the lever to stop the same and the tuning element at various predetermined positions and one of said stops normally being positioned for cooperation with said lever, mechanism for simultaneously swinging the lever away from said member out of cooperative-relation with the stops thereon and for rotating the member to bring anotheroi' said stops into position for cooperation with said lever, and means for returning said lever into contact with said 1 other stop.

v 6. In a tuning device for radio apparatus incorporating an adjustable tuning element, a pivoted lever having one end operatively connected with said tuning. element and actuable to adjustably position the. same, a disk member mounted for rotation adjacent said lever and carrying a plurality of radially adjustable stops circumferentially thereof, said stops being arranged in turn to individually cooperate with the lever to stop the same and the tuning element at various predetermined positions and one 01' said stops normally being positioned for cooperation with said lever, mechanism for simultaneously swinging the lever away from said disk out of cooperative relation with the stops thereon and for rotating the disk to bring another of said stops into position for cooperation with said lever, means for returning the lever into contact with said other stop, and mechanism operable to individually adjust the stops radially with respect to the disk.

'7. In a tuning device for radio apparatus incorporating an adjustable tuning element, a pivoted lever operatively connected with said tuning element and actuable to adjustably position the same, a disk carrying a pluralityot stops arranged peripherally thereof and each extending a predetermined distance therefrom, said disk being mounted for rotation adjacent said lever to position said stops successively for cooperation with the lever to stop the same and the tuning element at various predetermined positions and one of said stops normally being positioned for cooperation with said lever, mechanism for swinging the lever away from said disk out of cooperative relation with the stops thereon and for rotating the disk to bring the succeeding stop into cooperative relation with said lever, and resilient means for returning the lever into cooperative engagement with said succeeding stop.

8, In a tuning device for radio apparatus incorporating an adjustable tuning element, a first movable member operatively connected with said tuning element and actuable to adjustably position the same, a second movable member carrying a plurality of stops arranged for'individual cooperation with said first movable member to stop the same and the tuning element at various predetermined positions, one of said stops normally being positioned to cooperate with said first movable member, mechanism for moving the first movable member out of cooperative relation with the stops of the second movable member, a pivoted plate actuable by said mechanism operable to engage said second member to bring an- 7 other stop into position for cooperation with said first movable member, and means for returning "the first movable member into cooperative relation with said other stop.

ment and actuable toadjustably position the same,

a disk carrying a plurality of stops arranged peripherally thereof and each extending a predetermined distance therefrom, said disk being mounted for rotation adjacent said lever to position said stops successively for cooperation with the lever to stop the same and the tuning element at various predetermined positions and one of said stops normallybeing positioned for cooperation with said lever, means for swinging the 'porating an adjustable tuning element, a pivoted lever operatively connected with said tuning element and actuable to adjustably position the same, a disk carrying a plurality of adjustable stops arranged peripherally thereof and each extending a predetermined distance therefrom, said disk being mounted for rotation adjacent said lever to position said stops successively for cooperation with the lever to stop the same and 9. A tuning device for radio apparatus incorporating an adjustable tuning element, a pivoted 'lever operatively connected with said tuning element and actuable to adjustably position the same, a disk carrying a plurality of stops arranged peripherally thereof and each extending a predetermined distance therefrom, said disk being mounted for rotation adjacent said lever to position said stops successively for cooperation with the lever to stop the same and the tuning element at various predetermined positions and one of said stops normally being positioned for t cooperation with said lever, means for swinging the lever away from said disk out of cooperative relation with the stops thereon, a pivoted plate actuable by said means operable to engage and rotate the disk to bring the succeeding stop into cooperative relation with said lever, and resilient means for returning the lever into cooperative engagement with said succeeding stop.

10. In a tuning device" for radio apparatus incorporating an adjustable tuning element, a first movable member operatively connected with said tuning element and actuable to adjustably position the same, a second movable member carrying a plurality of stops arranged for individual cooperation with said first movable member to stop the same and the tuning element at various predetermined positions, one of said stops normally being positioned to cooperate with said first movable member, mechanism for moving the first movable member out of cooperative relation with the stops of the second movable member, a plurality of drive elements carried by said second movable member, a pivoted plate actuable by said mechanism operable to engage one of-said drive elements and move the said second member to bring another stop into position for cooperation with said first movable member, and means for returning the first movable member into cooperative relation with said other stop.

the tuning element atvarious predetermined positions and one of said stops normally being positioned for cooperation with said lever, means for swinging the lever away from said disk out of cooperative relation with the stops thereon, a pivotedplate actuable by said means operable to engage and rotate the disk to bring the succeeding stop into cooperative relation with said lever, resilient means for returning the lever into cooperative engagement .with said succeeding stop, and means operable at will for individually adjusting the stops with respect to said disk.

13. A tuning device for radio apparatus incorporating an adjustable tuning element, a pivoted lever operatively connected with said tuning element and actuable to adjustably position thesame, a disk carrying a plurality of adjustable stops arranged peripherally thereof and each extending a predetermined distance therefrom, said disk being mounted for rotation adjacent said lever to position said stops successively for cooperation with the lever to stop the same and the tuning element at various predetermined positions and one-of said stops normally being positioned for cooperation with said lever, mechanism for swinging the lever away from said disk Y out of cooperative relation with the stops there- 11. A tuning device for radio apparatus incor- I porating an adjustable tuning element, a pivoted lever operatively connected with said tuning eleon, a plurality of drive elements carried by said disk, a pivoted plate actuable by said mechasucceeding stop into cooperative relation with said lever, resilient means for returning'the lever into cooperative engagement with said succeeding stop, and means operable at will for individually adjusting. the stops with respect to said disk.

14. In a tuning device for radio apparatus incorporating an adjustable tuning element, a pivoted lever having one end operatively connected with said tuning element and actuable to adjustably position the same, a disk carrying a plurality of stops each extending a predetermined distance therefrom, said disk being mounted for 'step-by-step rotation adjacent the other end of said lever to position said stops successively for cooperation with said lever to'stop the same and the tuning element at various predetermined positions, a plurality of drive means carried by the disk, mechanism actuable to swing the lever away from said disk out of cooperative relation with the stops thereon, said mechanism includ-' ing means operable upon each actuation of the mechanism to engage one of said drive means on the disk and bring a succeeding stop into cooperative relation with said lever, and means for returning the lever into contact with said succeeding stop,

15. In a tuning device for radio apparatus incorporating an adjustable tuning element, a pivoted lever having one end operatively connected with said tuning element and actuable to ad justably position the same, a disk carrying a plurality of stops each extending a predetermined distance therefrom, said disk being mounted for step-by-step rotation adjacent the .other end of said lever to position said stops successively for cooperation with said lever to stop the same and the tuning element at various predetermined positions, a plurality of drive means carried by 16. In a tuning device for radio apparatus incorporating an adjustable tuning element, a first movable member operatively connected with said tuning element and actuable to adjustably position the same, a second movable member carrying a plurality of stops arranged for individual stop the same and the tuning element at various predetermined positions, one of said stops normally being positioned to cooperate with said first movable member, drive means carried by said second movable member, mechanism for moving the first and second movable members including a pair of resiliently coupled link elements, one of said link elements being in driving relation with said first movable member and operable to move the same out oi! cooperative relation with the stops of the second member and the other of said link elements being arranged to engage the drive means on said second member and rotate the same to bring another stop into cooperative relation with the first movable member, means in driving relation with one of said link elements for actuating the same, and means for returning the first movable. member into cooperative engagement with said other stop.

, 17. In a tuning device tor radio apparatus incorporating an adjustable tuning element, a pivoted lever having one end operatively connected with said tuning element and actuable to adjustably position the same, a member mounted for rotation'adjacent said lever and carrying a plurality of stops disposed about its periphery, said stops being arranged in turn to individually cooperate with the lever to stop the same and the tuning element at various predetermined positions and one of said stops normally being positioned for cooperation withsaid lever, a plurality or drive pins carried by said disk, mechanism operable to swing the lever away trom the cooperation with said first movable member to disk out of cooperative relation with the stops thereon, a pivoted plate actuable by said mechanism and having oscillatory motion defining a drive stroke and a return stroke upon each actuationthereoi, and said plate having an opening therein arranged during the drive stroke of the plate to engage one of the drive pins on the disk and rotate the latter to bring another stop into cooperative relation with said lever, and means forreturning the lever into cooperative engagement with said other stop.

18. A construction as claimed in claim 17 wherein the pivoted plate is provided with an oilset portion Iorming a clearance constructed and arranged to permit the drive pin engaged and actuated during the driving stroke of said plate to escape from the opening in the plate during the return stroke of said plate.

19. A construction as claimed in claim 17 wherein the pivoted plate is provided with a ramp portion operable during a return stroke of the plate to guide and position the succeeding drive pin in the opening in the plate for engagement and actuation thereby uponsubsequent actuation of said plate.

20. A construction as claimed in claim 17 wherein the pivoted plate is provided with an ofiset portion and a ramp portion adjacent the opening therein, said offset and ramp portions being operable during the return stroke of said plate respectively to permit the drive pin engaged and actuated during the drive stroke of the plate to escape from said opening and to permit passage of th succeeding drive pin into the opening for engagement and actuation by the plate during the next driving stroke thereof.

21. In a tuning device for radio apparatus incorporating an adjustable tuning element, a first member operatively connected with said tuning element and actuable to adjust the-same, a second member carrying a plurality of stops adapted individually to cooperate with said first member, drive means for actuating the first member away from said second member and the stop thereon, means for returning said drive means to its original position after actuation of said first member, means operative independently of said drive means for moving the first member back into contact with one of said stops, and a lost-motion connection between said drive means and said first member operable to permit the first member to be returned difierent distances than said drive means and tree from interference with the full return of the latter to its original position.

' 22'. A construction as claimed in clam 3 wherein the actuating mechanism comprisesa first link mounted for pivotal movement around a fixed point, a second link adapted to be driven by said first link and having an elongated aperture therein, connecting means carried by the first link slldably engaging the aperture in said second link, an actuator including an armature having a driving connection with said first link, and means for returning said armature to its original position after each actuation oi the drive means.

23. In a tuning device for radio apparatus incorporating an adjustable tuning element, a movable member operatively connected with said element and actuable to adjust the same, a disk mounted for rotation adjacent said member, a plurality of stop elements carried by said disk in threaded relation therewith-and each of said stops being arranged to extends predetermined distance radially outward from the disk for individual cooperation with the movable member to stop the same and the tuning element at various predetermined preselected positions, means for effecting step-by-step rotation of said disk to position said stops successively in cooperative relation with said movable member, and means engageable with said stops when positioned for cooperation with the movable member operable manually to project orv retract the stops radially with respect to the disk and thereby selectively predetermine the positions in which the movable member will be stopped.

24. In a tuning-device for radio apparatus incorporating an adjustable tuning'element, a movable member operatively connected with said element and actuable to adjust the same, a disk disk and one 01 said stops normally being so sitioned to cooperate with thepivoted lever,

sition for cooperation with the pivoted lever,

means for returning said pivoted lever into cooperative relation with said other stop, and

mounted for rotation adjacent said member, a

' plurality of stop elements carried by said disk in threaded relation therewith and each of said stops being arranged to extend a predetermined distance radially outward from the disk for individual cooperation with the movable member to stop the same and the tuning element at various predetermined preselected positions, means for effecting step-by-step rotation of said disk to position said stops successively in cooperative relation with said movable member, and means engageable with said stops when positioned for cooperation with the movable member operable manually to project or retract the stops radially with respect to the disk and thereby selectively predetermine the positions in which the movable member will be stopped, said means normally overlying said disk out of contact with most of the stops thereon and being actuable into contact with said stops individually for adjusting the same as the stops are positioned for cooperation with said movable member.

25. In a tuning device for radio apparatus incorporating' an adjustable tuning element, a first movable member operatively connected with said tuning element and. actuable to adjust the same,

of cooperative relation with the stops of the see ond movable member and for moving said second member to bring another sto into position for cooperation with said first movable member, means for returning the first movable member into cooperative relation with said other stop, and means arranged normally to engage the one stop disposed at a level above the other stops when said one stop is positioned for cooperation with its first movable member, said means being operable manually to adjust said one stop and vary the positionof the-tuning element for manual tuning of the device.

26. In a tuning device for radio apparatus incorporating an adjustable tuning element, a pivoted lever having one end operatively connected with said tuning element and actuable to adjustably position the same, a rotatable disk carryinga plurality of circumferentially disposed stops arranged for individual cooperation with said pivoted lever to stop the same and the tuning element at various predetermined positions, said stops being adjustable relative to the rotatable mechanism operable to individually adjust the stops with respect to the rotary disk, said means normally overlying said disk out of contact w th most of the stops thereon and being actuable into contact with said stops individually for adjusting the same as the stops are positioned for cooperation with said movable member.

27. In a tuning device for radio apparatus incorporating an adjustable tuning element, a pivoted lever having one end operatlvely connected with said tuning element and actuable to adjustably position the same, a rotatable disk carrying a plurality of circumferentially disposed stops arranged for individual cooperation with said pivoted lever to stop the same and the tuning element at various predetermined positions, said stops being adjustable relative to the rotatable disk and one of said stops normally being positioned to cooperate with the pivoted lever, one of said stops being disposed at a level above the other stops. mechanism for simultaneously actuating said pivoted lever out of cooperative relation with the stops of said rotatable disk and for moving the rotatable disk and for moving the rotatable disk to. bring another stop into position for cooperation with the pivoted lever, means for returning said pivoted lever into cooperative relation with said other stop, and means arranged normally to engage the one stop disposed at a level above the other stop when said one stop is positioned for cooperation with the first movable member, said means being operable manually to adjust said one stop and vary the position of the first movable member and the tuning element vfor manual tuning of. I the device.

28. In a tuning device for radio apparatus in- I corporating an adjustable tuning element, a pivoted lever having one end operatively connected withsaid tuning element and actuable to adjustably position the same, a rotatable disk carrying a plurality of circumferentially disposed stops arranged for individual cooperation with said pivoted lever to stop the same and the tunin element at various predetermined positions, said stops being adjustable relative to therotatable disk and one of said stops normally being positioned to cooperate with the pivoted lever, one

of said stops being disposed at a level above the other stops, mechanism for simultaneously actuating said pivoted, lever out of cooperative relation with the stops of said rotatable disk and for moving the rotatable disk to bring another stop into position for cooperation with the pivoted lever, means for returning said pivoted lever intb cooperative relation with said other stop, and means arranged normally to engage the one stop disposed at a level above the other stops whenrsaid one stop is positioned for cooperationcooperation with said lever thereby to adjust said other stops.

29. In a tuning device for radio apparatus incorporating a tuning element capable of both manual and automatic adjustment, a movable member operatively connected with said element and actuable to adjust the same, an element carrying a plurality of stops extending therefrom and each adapted to cooperate with said member to position the same, said stops further being adjustable with respect to said stop-carrying element to vary their extension therefrom, drive means for said movable member cooperating with certain of said stops to automatically and selec-- tively position said member, one of said stops being adapted to vary the position of said movable member under the manual condition of operation, and means including a manual control movable between two positions and adjustable in each, ad-

'justment of said control when in one position serving to actuate said manual tuning stop, and adjustment when in the other position serving to vary the extension of the automatic positioning stops. i

30. A construction as claimed in claim 29 wherein the stops are in threaded engagement with the element and the manual control comprises a rotatable friction element engageable with said stops to rotate and thereby adjust the same. 31. For a radio tuning device capable of both automatic and manual control, a ,rotatable'disk carrying a plurality of stops each in turn adapted when in operative position to determine the tuning position of said device, said stops comprisin screw elements in threaded engagement with said disk with their longitudinal axes lying on substantially radial lines thereof, means for effecting step-by-step rotation of said disk, one of said stops lying at a different elevation than the others of said stops, a manually rotatable friction element mounted for movement toward and away from said disc and adapted to engage said stops to rotate and thereby vary the radial extension thereof from said disk, and resilient means normally urging said friction element away from said disk, said friction element being arranged normally to engage the stop of different elevation when in operative position to efiect manual control of said tuning element, and said friction element being engageable with the others of said stops when in operative position to vary their radial extension from said dish upon movement of the friction element toward the disk against the action of said resilient means.

32. In a tuning device for radio apparatus incorporating an adjustable tuning element, a member operatively connected with said tuning element and actuable to adiust the same, a disk carrying a plurality of stops each extending a different distance therefrom, said disk being mounted for step-by-step rotation adjacent said member to position each of said stops for individual cooperation with the member to stop the same and the tuning element at various predetermined positions, means for simultaneously moving said member away from the disk and for rotating said disk to, bring another stop into cooperative relation with the member, means for returning said member into contact with said other stop, and manually operable means arranged for cooperation with at least one of said stops when positioned to cooperate with the member thereby to vary the extension of said stop from the disk and provide manual control of the tuning element by varying the position of said member.

33. In a tuning device for radio apparatus incorporating an adjustable tuning element, means operatively associated with said element for adjusting the same and including a plurality of stops arranged individually to cooperate .with said tuning element to stop the same at various predetermined positions, actuating mechanism operable simultaneously to actuate said means and the tuning element associated therewith and to cooperatively position one of said stops, means for returning said mechanism to rest position after each actuation thereof, and means operative independently of said actuating mechanism for returning the tuning element to a predetermined rest position after actuation thereof by said mechanism.

34. In a tuning device for radio apparatus incorporating an adjustable tuning element, means operatively associated with said element for adiusting the same and including a movable member and a plurality of stops arranged individually to cooperate with said member to stop the same and the tuning element at various predetermined positions, actuating mechanism operable simultaneously to actuate said means and the tuning element associated therewith and to cooperatively position one of said stops, means for returning said mechanism to rest position after each actuation after each actuation thereof.

r rannY .r. LYMAN. DONALD n. rims. WALTER. n. rnrmnron.