US2114540A - Tuning mechanism for radio apparatus - Google Patents

Description

April 1938. v. c. MACNABB 2,114,540

TUNING MECHANISM FOR RADIO APPARATUS Filed March 8, 1937 v 3 Sheets-Sheet l INVENTOR. 3* VEANd/V CI MiG/V1458 GZML 4. A

A TTORNE Y.

April 19, 1938.

v. c. MACNABB 2,114,540

TUNING MECHANISM FOR RADIO APPARATUS Filed March 8, 1957 5 Sheets-Sheet 2 INVENTOR- VERNON 6! Mac/V1455 GEM/.45

A TTORNE Y.

April 19, 1938. MACNABB 2,114,540

TUNING MECHANISM FOR RADIO APPARATUS Filed March 8, 1957 3 Sheets-Sheet 3 INVENTOR. VERA/01v CT Mac/v0.95

BYQMKQAQV ATTORNEY. I

Patented Apr. 19, 1938 PATENT OFFIQE TUNING MECHANISM FOR RAD-IO APPARATUS Vernon C. Macnabb, Indianapolis, Ind., assignor to Fairbanks, Morse poration of Illinois Application March 8,

12 Claims.

This invention relates to tuning mechanism for radio apparatus, and more particularly to an improved tuning dial organization for radios of multiple wave-band type.

It has been the general practice heretofore, to provide in connection with multiple wave-band radio apparatus, a single tuning dial having thereon tuning indicia for the several bands. One of the disadvantages of such a dial arrangement is that all of the tuning indicia are simultaneously visible, resulting in many instances, in a confusion of wave band indication during tuning. Moreover, where all the indicia for aplurality of wave bands are simultaneously visible, the array of indicia offers of itself a degree of confusion to the operator. Accordingly, it is an. object of the present invention to provide a radio tuning indicator characterized by the selective display of the tuning indicia for but one wave band at a time.

Among other objects of the invention are the provision of a tuning indicator for a multiwave band radio having visible only the band indicia of the particular wave band desired; the provision of a tuning indicator having a separate dial member for each wave band, with the dial members relatively displaceable so that only one thereof will be visible at any one time, and the provision of regulating means for the indicator, adapted to operate the several dial members in sequence to obtain the visibility of but one dial member at a time, the regulating meansbeing operated preferably by the control element provided for changing the circuit arrangement of the radio from one wave-band to another.

Further objects and advantages will appear from the description and accompanying drawings, in which:

Fig. 1 is a front elevation of a partly assembled radio chassis, illustrating the improved waveband indicator of this invention; Fig. 2 is a fragmentary plan view of the radio chassis of Fig. 1, showing the front panel of the radio in section, and the disposition of the indicator mechanism relative thereto; Fig. 3 is an enlarged, fragmentary sectional elevation of the radio chassis and front panel, illustrating certain details of the improved indicator, the view being taken from line 3-3 in Fig. 1; Fig. 4 is an enlarged side elevation of a part of the indicator, with portions thereof shown in section, as taken along line 4-4 in Fig. 1; Fig. 5 is a front elevation of the device shown by Fig. 5, as viewed from line 5-5 thereon, the View, however, showing certain of the elements in an altered position from that indicated & 00., Chicago, 111., a cor- 1937, Serial No. 129,639

for these parts in Fig. 4; Fig. 6 is a view in detail, of a portion of the mechanism shown by Fig. 4; Fig. '7 is a sectional view of a part of the mechanism, as taken along line 'L-l in Fig. 4,

' and Fig. 8 is an elevation shown partly in section, of the mechanism of Fig. 4, as viewed from line 8-8 thereon.

Referring now to the drawings by suitable numerals of reference, the improved indicator is operatively associated with the tuning mechanism of a multi-wave band radio, as will now appear. As shown in Figs. 1, 2, and 3, the radio chassis is indicated generally at if], the chassis supporting the radio instruments and apparatus, as for example, a multiple capacity unit of variable type indicated at H, and a multiple circuit switching device l2 provided for adjusting the apparatus to receive signals in any one of a number of different wave bands. The switching device I2 is operated by a shaft 13 extending to the front of the radio panel [4, the shaftbeing provided with a control handle or knob 15 for manual manipulation thereof. For convenience and simplicity of control, the shaft l3 controlling the shifting of the circuit connections to accommodate the different wave bands, is utilized to regulate the wave band indicator mechanism now to be described.

The panel 14 is provided with an opening 16 of square, circular or other desired configuration,

the opening being closed preferably on the back or inner face of the panel, by a transparent member I! such as a glass plate. By preference, the glass H is carried by a substantially rigid opaque member or mask 18 formed of either metallic or non-metallic sheet material, the mask it being supported by the chassis H] in any suitable'manner, as by the bolts l9 and spacer sleeves 20 extending between the member and a bracket 28 secured to a side wall 22 of the chassis. Mounting of the glass H on the mask it may be effected in any desired manner, as by the clips 2E3 shown in Fig. 1, As appears in Figs. 2 and 3, the sleeves 20 serve to space the member 18 and glass ll outwardly of the chassis wall 22 so that in the assembly relation of the chassis I0 and panel Hi, the glass will seat against the inner side of the panel in a position to close the panel opening l6.

Referring to Figs. 1 and 3, the mask I8 is provided with a substantially semi-circular opening or window 24 to permit observation of tuning indicia disposed on relatively displaceable dial elements arranged rearwardly of the member 18, as will later appear. In addition, a second slot or Window 25 of smaller extent is formed in the member l8, above the slot 24 in the position shown in Fig. 1, this second slot being provided to permit observation of wave band indicia associated with the tuning indicia, as will be presently described. Arranged rearwardly of and in relatively close adjacence to the member l8, are a plurality of substantially semi-circular dial elements, four being shown in the present example, and numbered 26, 2'1, 28, and 29, the element 26 being that closest to the member l8. ments are formed of relatively thin, sheet material, such as steel, aluminum or bakelite, and

each is provided with .a portion 39 extended upwardly from the mid-section of the semi-circular portion of the element, for a purpose presently to appear. As shown in Figs. 2 and 3, the elements are arranged in horizontally spaced relation, one in back of another, so that in the position shown, only the element 26 will have surface portions thereof in register with and exposed through the slots 24 and 25, respectively. Arranged along that surface of the dial element 26 which is exposed through the slot 24, are tuning 'graduations 3| and wave length indicia 32. The surface of the extension 39 on element 26 which is exposed through the slot 25, is provided with a suitable indicator of the wave band corresponding to the graduations 3| and wave length indicia 32, this indicator in the present example, being the word Broadcast. Each of the remaining elements 21, 28, and 29 is similarly provided with an indicator of a particular wave band and indicia of wave length corresponding thereto, although such indicia and band indicators are not shown in the present disclosure. It is understood, of course, that the dial elements are associated with a variable tuning device of the radio to indicate the tuning condition thereof. In the present example, the tuning device is the variable capacity device or condenser The rotary elements of the condenser are operated through the condenser shaft 34, and in the present example the shaft extends toward the radio panel I4, and has a dial hand or pointer 36 mounted thereon which plays over the dial face bearing the tuning indicia visible through window 24, as. the condenser is operated.

As before noted, with the elements 26 through 29 in the positions shown in Figs. 2 and 3, only the tuning indicia and wave band indicator on element 26 .are visible through the slots 24 and 25. To expose the indicia and wave band indicator on element 21, the element 26 is adapted in a manner later appearing, tobe displaced sufficiently to permit visibility of the tuning indicator element 27 through the slots 24 and 25. Likewise, the element 2'! is displac eable so as to expose the tuning indicia and band indicator on element 28, and similarly the element 28 is displaceable to expose the indicia on element 29. Since in the present example, the element 29 is the last of the roup, it may be retained in its original position and thus will be exposed only when all the other elements have been displaced. Hence, it will be readily observed from the fore going, that at any given time, only one of the elements 28 through 29 will be in. position for exposure of its band indicator and tuningiindicia through the windows 24 and 25. V

The dial elements 26, 21, and 28 are adapted for sequential displacement, for the purpose above noted, through mechanism now to be'described. Each of these elements is formed with a lateral extension 31 terminating in a projection or tail piece 38. The elements are pivotally supported The eleupon a sleeve 39 mounted on a shaft or plunger 4|, the sleeve extending through the extensions 37, as shown in Fig. 4. As a. means for preventing frictional or rubbing contact between adjacent dial elements, and also for providing greater rigidity of the elements at the zone of pivotal support, each of the elements is secured in any suitable manner, to a spacer member 42. The dial extensions and spacers are confined longitudinally of the sleeve, between a shoulder 44 formed on one end of the sleeve and a removable end plate 45 at the opposite end of the sleeve, the plate 45 being retained in assembly by a screw 46 threadedly engaging the shaft 4|. To prevent longitudinal displacement of the sleeve 39 on shaft 4|, the shaft end is formed of reduced diameter, to provide a shoulder 47 against which the shouldered sleeve end 44 seats, in the assembly of the parts.

The shaft or plunger 4| is journalled for longitudinal sliding movement, in a bearing member 48 carried by and extending through a portion of the bracket 2| heretofore noted, said bearing member having an external, rounded shoulder 50 for a purpose later to appear. The shouldered portion of the bearing member is disposed outwardly of one side of the bracket 2| and adjacent the shouldered end of the dial supporting sleeve 39, as shown in Fig. 4. Formed by preference, as an integral part of the bearing 48 and extending through bracket 2|, is a tubular member or cylinder 5|. The shaft 4| extends into the cylinder 5| and is provided with a head element 54, the peripheral surface of which seats against the internal wall surface of the cylinder, after the manner of a piston. A compression spring 55 is sleeved about the shaft 4|, and confined between the shaft head 54 and an internally shouldered part of the cylinder, thus serving to bias the sleeve 39 and dial elements thereon in a direction away from the panel i4.

Mechanism of a preferred type now to be described, is provided for controlling both longitudinal shifting of the shaft 4| and hence of the dial elements 26 through 29, and pivotal displace .ment of the dial elements for the purpose heretofore noted. The purpose for the longitudinal shifting of the dial elements will appear as the description proceeds.

As shown in detail in Figs. 4 through 8, the dial shifting mechanism comprises a substantially channel-shaped frame 51 provided with a slot 58 in the bridge portion 59 thereof, the slot extending substantially the length, yet terminating short of the ends of said bridge portion. The sides 6| of the frame 57 are substantially triangular in side elevation, as shown in Fig. 4, the edge 62 of each side corresponding to the hypotenuse of the triangle, serving as a camming edge for a purpose presently to appear. In the assembly of the frame to the dial mechanism, the shaft 4| extends through the slot 58, while the solid portions of the bridge engage the shoulder 44 of the dial carrying sleeve 39. The frame sides 6| straddle the shaft and the camming edges 62 engage the rounded bearing shoulder 50, in the manner shown in Fig. 4. From the foregoing, it will be observed that the spring 55 acting on the shaft 4 I, and hence on the sleeve 39 serves through these elements to urge the camming edges 62 of the frame against the shoulder 50.

As a means for attaining stability of the frame 51 in assembly and during its operation as will be later described, and also, for confining the frame to a linear movement of an extent determined by the length of the frame slot 58, there is provided a shaft or plunger 64 spaced from the shaft 4! and longitudinally slidably journalled in a bearing member 65 secured to the bracket 2!, with the shaft extending through the frame slot 58. The shaft 64 is urged in one direction of its slidable movement by a spring 61 sleeved upon the shaft and bearing against the shaft head 68. The spring, shaft, and shaft head are arranged within a cylinder 18 which may be formed as an integral part of the bearing member 65. Threadedly engaging an internal bore in the outer end of shaft 64, is a rod H provided for a purpose later to appear, the rod having a. flange 12 seating against the end of shaft 54 and in engagement with the bridge portion 59 of the sliding frame 51. The bearing member 65 extends outwardly from bracket 2| a greater distance than does the bearing member 48 heretofore described in connection with shaft 41, and has its exposed end 13 rounded as shown, to provide a bearing seat for the camming edges 62 of frame 51. Thus the frame is confined between the end 13 of bearing member 85 and the flange 12 on rod 1|, so that the spring 6'! acting on the shaft 64 and hence on the flange 12, tends to urge the camming edges 62 of the frame against the bearing seat 13.

It will be observed from the foregoing description and from an inspection of Fig. 4, that downward displacement of the frame 51 from its upper extreme position shown in Fig. 4, will result in an outward shifting of the plungers or shafts 4| and 64, against the pressure of the respective springs 55 and 6? acting thereon, this shifting of the shafts being efiected by reason of the wedging action of the frame 51 on the said shafts. The provision for the shifting of the shafts, particularly shaft t i is made for the purpose of displacing the assembly of dial elements so that the particular element being disclosed will be close to the window 24 in. panel M. By regulating the actuation of frame 51 to attain a step-by-step movement thereof, the shifting of the dial elements may be controlled so that say upon the displacement of dial element 26, the dial element 21 will be shifted into substantially the spacial position formerly occupied by element 26. Further downward movement of the frame 57 during displacement of the element 21, will bring the element 28 into the space formerly occupied by element 21, and so for the last element 29. Thus successive movements of the frame in steps, will attain the desired shifting of the elements, and it is to be noted that the results above described will occur in reverse order upon successive upward movements of the frame 51.

Actuation of the frame in a step-by-step manner, is attained through the operation of the circuit changing switch l2 through the control shaft l3. For this purpose, the lower end of the frame 51 is provided with a laterally extending arm 14 having therein a slot 15, the longitudinal axis of which is substantially at a right angle to that of the frame slot 58. Extending through the slot 15 is an element or rod 76 having one end thereof secured in any suitable manner, to an actuating arm 19. The arm 19 is operatively secured to the switch control shaft I 3 by a lock screw 82. Thus by rotating the shaft I3, through the handle l5, the frame El will be actuated through the arm i9 and rod 16 in the slot 15 of the frame arm 14. As will be readily understood, the purpose for the slot 15 is to permit movement of the actuating rod 16 therealong during rotation of the arm 19, since the frame 51 is confined to linear movement only. In operating switch I 2 to change the radio circuit connections, the switch shaft I3 is rotated in steps, the angular extent of rotation thereof in each step being determined by the spacing of the switch contacts (not shown). Accordingly, the stepped movement of shaft [3 will effect a corresponding stepped movement of the frame 51, and the extent of linear movement of the frame in each step is correlated with the extent of rotary movement of shaft IS in each step so as to attain the desired degree of shifting movement of the dial elements. Such correlation of movements is effected through proper design and relation of the elements above described, operatively connecting the shaft l3 and frame 51.

Turning now to the mechanism for effecting successive displacements of the several dial elements, this is effected simultaneously with the shifting of the dial elements by the frame 51, through a member 86 secured to one arm of the frame, as by the screws 81. The member 86 which may be a substantially rectangular plate formed of any suitable rigid material, extends outwardly and longitudinally of the frame, being parallel to the arms of the frame, and is provided with a central aperture or opening 88 of triangular aspect. The marginal portion of the plate aperture, defining a side corresponding to the hypotenuse of the triangularly shaped opening 88, is stepped at 98, 5!, 92, and 93, as shown in Fig. 6, with the lower ends of the stepped portions provided with an outturned lip or finger 94, 95, 96, and 91 respectively, as shown in Fig. 5. The lips or fingers on plate 85 are provided for effecting a pivotal displacement of the dial elements, in a manner presently to be described.

Each of the dial elements is urged to its initial position behind the member i8 and in register with the windows 24 and 25 therein, by a spring 98 having one end secured to the dial extension 3'! and its opposite end secured to the rod H on shaft 64. Four such springs are Shown, one for each of the dial elements 28 through 29, although the spring for the last dial element 29 may be omitted, if desired, as this element is normally retained in its original position at all times. The position of the dial elements behind the member I8 so that the tuning indicia thereon will be in register with the windows 24 and 25, is determined by a suitable stop element 582 (Figs. 3 and 5) carried by the bracket 2 i. If desired, the stop may be provided by one of the supporting elements for the mask l8, such element being comprised of a bolt !9 and sleeve 28 as heretofore noted. The stop is provided with an abutment I83 sleeved thereon, the abutment being formed of any suitable material, such as aluminum or bakelite. Moreover, securing the springs 98 to the rod H on shaft 64 serves to maintain the axis of each spring in the plane of its dial element during shifting of the dial elements by the frame 51, as shaft il supporting the dial elements, and shaft 64 supporting rod H are moved an equal distance upon each actuation of the frame 51.

The arrangement of the plate 86 on frame 5'! is such that with the plate and frame in the uppermost position, as shown in Fig. 4, the dial elements will be disposed in their initial position (Figs. 2 and 4) with the tail pieces 38 thereof extending through the lower end of the opening 83 in plate 86 (Figs. 4 and 6). In this position of the several dial elements, the tail piece 38 of dial element 26 is disposed to underlie the actuating finger 94. The tail pieces 38 of the other dial elements 21, 28 and 29 are in vertical register but out of engagement with the fingers 95, 96, and SH, respectively. Thus upon downward movement of the frame 57 and plate 86, as effected by actuation of shaft l3, the finger 94 will act upon the tail piece 38 of dial element 26, to pivot the dial element upwardly and outwardly from its initial position behind the windows 24 and 25, into the position indicated at I05 in Fig. 5. In the displaced position I05 of the element 25, the edge N26 or its extension 31 rests against the plate 85, and the element is retained in such position against the bias of its spring 98, by the finger M and surface portion of the plate 86. Simultaneously with the displacement of dial element 25 and as a result of the downward movement of the frame El as heretofore described, all the dial elements are shifted toward the panel l4 so as to bring the next succeeding dial element 2'6 into the space formerly occupied by dial 265, in register with the windows 24 and 25. Successive downward movements of the frame 51 and plate 86 effect in turn, similar positioning of the other dial elements 21 and 28. Actuation of shaft It so as to move frame El and plate 86 upwardly, successively releases the dial elements, in the reverse order of their displacement, permitting the springs 98 to return the elements to their original positions. At the same time, the dial elements are shifted axially of shaft :1! and in a direction away from the panel l4, under the action of the camming frame 51' and springs 55 and 51 acting respectively, on shafts 4i and E l, so as to return the dials to their original position rearwardly of the panel.

From the foregoing, it will be observed that the mechanism for positioning the tuning dial elements is actuated and controlled by the circult changing device for the radio, and the arrangement is such that upon actuation of the circuit changing device to effect circuit connections for reception on a particular wave band. the tuning dial element corresponding to such wave band will be disposed in register with the windows 24 and 25 for visibility of the tuning indicia on such dial. Thus, when the circuit changing device is in position to effect reception on the Broadcast band, this being one extreme position of the device, the dial 26 which is the Broadcast band dial, will be in position for observance of its tuning indicia through window 24 and band indicator Broadcast through window 25. When the switch i2 is actuated by shaft l3, through one step to the next succeeding position determining a different circuit connection for reception on another wave band, dial 2? corresponding to such wave band, will be in position for observance of its tuning indicia through window 24 and its band indicator through window 25, and similarly for the remaining dial elements.

Thus, the present invention provides a tuning indicator mechanism for a multi-wave-band radio, the indicator being characterized by the selective display of tuning indicia for but one wave band at a time. Moreover, the display of tuning indicia corresponding to a given. wave band is made coincidentally with the actuation of the circuit changing device of the radio, to effect the circuit connections for reception on the given wave band.

It is to be understood that the invention is not to be limited to the herein described embodiment thereof, but that alterations and modifications may be made therein without departing from the spirit and full scope of the invention, as defined by the appended claims.

I claimi 1. A tuning dial mechanism of the character described, comprising a plurality of dial elements normally disposed in spaced relation, a member pivotally supporting said dial elements, said member being capable of axial movement to effect axial displacement of said elements, and means operatively associated with said dial elements and with the supporting member therefor, adapted for effecting concurrently, pivotal and axial displacement of said dial elements.

2. A tuning dial mechanism of the character described, comprising a plurality of dial plates normally disposed in spaced, parallel relation, a member pivotally supporting said plates, said member being capable of axial shifting movement to efiect axial displacement of said dial plates, means operable to axially shift said supporting member and dial elements, and means operated by said shifting means, adapted for pivotally displacing said dial plates.

3. A tuning dial mechanism of the character described, comprising dial elements normally disposed in spaced relation, means supporting said elements for both pivotal and axial displacement, and means operatively associated with said dial elements, adapted for effecting pivotal and axial displacement of each of said dial elements.

l. A tuning dial mechanism of the character described, comprising dial elements normally disposed in spaced, parallel relation, means supporting said elements for both pivotal and axial displacement, and means operatively associated with said dial elements and said supporting means, adapted for effecting, coincidentally, pivotal and axial displacement of each of said dial elements.

5. In combination with radio apparatus including a tuning device, a panel and an opening in said panel, a tuning dial mechanism comprising dial plates arranged in spaced, parallel relation, means supporting said plates for both pivotal and axial displacement, means biasing said plates to a position in register with said panel opening, and means operatively associated with said dial plates, adapted for effecting a coincidental pivotal and axial displacement of each of said dial plates out of register with said panel opening.

6. In combination with radio apparatus including a tuning device, a circuit changing device, a panel and an opening in said panel, a tuning dial mechanism comprising dial elements arranged in spaced, parallel relation, means supporting said elements for both pivotal and axial displacement, means biasing said elements to a position in register with said panel opening, and means operatively associated with said dial elements and actuated by said circuit changing device, for effecting sequential displacement of said dial elements out of register with said panel opening and coincidentally therewith, axial displacement of said elements.

7. In combination with radio apparatus including a tuning device and a circuit control device, a tuning dial mechanism comprising dial plates arranged in spaced, parallel relation, means supporting said elements for both pivotal and axial displacement, a camming member operatively associated with said suppporting means, adapted for effecting axial displacement of said dial plates, actuating mechanism for said camming means, operated from said circuit control device, and means on said camming member, adapted coincidentally with the actuation of said camming member, to effect pivotal displacement of said dial plates.

8. In combination with radio apparatus including a tuning device, a circuit control device, a panel and an opening in said panel, a tuning dial mechanism comprising dial elements arranged in spaced, parallel relation, means supporting said elements for both pivotal and axial displacement, means for biasing said dial elements to a position in register with said panel opening, a camming member opera'tively associated with said supporting means, adapted for effecting axial displacement of said dial elements, actuating mechanism for said camming means, operated from said circuit control device, and means on said camming member, adapted coincidentally with the actuation of said camming member, to effect pivotal displacement of said dial elements out of register with said panel opening.

9. In combination with radio apparatus including a tuning device, a tuning dial mechanism therefor, comprising dial elements arranged in spaced relation, means supporting said elements for both pivotal and axial displacement, a cam operatively associated with said dial elements for axial displacement thereof, and a member movable with said cam and provided with spaced projections arranged for engagement with said dial elements as the cam is operated, to effect pivotal displacement of said dial elements.

10. In combination with radio apparatus including a tuning device and a circuit control device, a tuning dial mechanism comprising dial elements arranged in spaced relation, means supporting said elements for both pivotal and axial displacement, a cam operatively associated with said dial elements for axial displacement thereof, said cam being actuated by said circuit control device, and a member movable with said cam and provided with spaced projections thereon arranged for engagement with said dial elements as the cam is operated, to effect pivotal displacement of said dial elements. 1

11. In combination with radio apparatus including a tuning device, a tuning dial mechanism therefor, comprising dial elements arranged in spaced relation, a projection on each of said elements, means supporting said elements for both pivotal and axial displacement, a cam operatively associated with said dial elements for axial displacement thereof, and a member movable with said cam and provided with spaced projections arranged for successive engagement with the projections on said dial elements as the cam is operated, to effect a successive pivotal displacement of said dial elements.

12. In combination with radio apparatus including a switch for adjusting the apparatus to receive signals in any of a plurality of wave bands, a control for said switch, a plurality of dial plates, each bearing tuning indicia for signals in one of said wave bands, a panel for concealing said plates, having an opening for revealing the tuning indicia of any one thereof at a particular time, a shaft, means mounting said dial plates for independent pivotal movement and conjoint translatory movement on said shaft, to- Ward and from said panel opening, means for moving the dial plates as aforesaid, means operatively interconnecting said switch control and said dial moving means, and a manipulating element for effecting joint actuation of said. switch control and dial moving means.

VERNON C. MACNABB.

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