US2023935A - Band-spreading tuning device - Google Patents

Description

J. F. RILEY zmww BAND SPREADING TUNING DEVICE Filed Aug. 15, 1934 2 Sheets-Sheet l Em M 1935.,

J. F. RILEY 2&23335 BAND SPREADING TUNING DEVICE Filed Aug. 13, 1954 2 Sheets-Sheet alarly in the short wave bands.

results in a large change in frequency.

tor. change in capacity for a given rotation of a Patented Dec. 10, 1935 PATENT OFFICE BAND- SPREADIN G TUNING DEVICE Joseph F. Riley, Chicago, 111., assignor to Howard Radio Company, Chicago, 111., a corporation of Illinois Application August 13, 1934, Serial No. 739,667

'18 Claims.

This invention relates to tuning devices for radio receivers, and more particularly to such a device wherein band-spreading is achieved.

-One feature of this invention is that it permits conventional tuning throughout the broadcast band; another feature of this invention is that itpermits band spreading in the particular bands of the radio spectrum in which that is desirable; still another featureof this invention is that it combines two indicators on one dial, said indicators showing conventional operation and band spreading operation, respectively; yet another feature of this invention is that when theband spreading mechanism is operative station settings are spaced much farther apart on the dial than during conventional operation; another feature of this invention is that it eliminates additional condensers; other features and advantages of this invention will be apparent from the followingspecification and the claims, in which Figure l is a front-elevation of the dial and manual operating means; Fig. 2 is a sectional view along the line 22 of Fig. 1. I

It has long been considered necessary to achieve band-spreading action in certain points of the frequency spectrum, and more particu- In all wave sets, the principal condenser or gang of condensers must have sufl'icient maximum capacity to tune throughout the broadcast range. This capacity is so large that where the same condensers are .used in connection with short wave reception in the set, a very small rotation of the rotor plates This large change of frequency per degree of rotation results in certain defects as, for example, the fact that weaker stations are passed over completely, and resonance with the carrier band of the desired station is much more diihcult to attain, especially in the hands of an inexperienced opera- Various methodsof reducing the effective manual operating means have beenknown. Most of these methods, however, are electrical in character, requiring a separate variable condenser of smaller capacity, or a separate fixed condenser adapted to be placed in circuit with the main condenser. This invention enables the main condenser tobe used throughout all the bands of the desired spectrum, and provides a conventional manual drive for use in the longer wave lengths,

"and a much lower geared drive for use where hand-spreading is desired. This invention also ,provides two separate indicators cooperating on one .dial, thus enabling normal operation and .at the point 35.

band-spreading operation to be indicated on the one dial.

In the particular embodiment of the invention illustrated herewith, a panel H] has mounted thereon a dial l I having an outer'calibrated por- 5 tion I2 and an inner calibrated portion I3. Concentrically mounted in relation thereto are two indicator needles, a main indicator l4 and a band-spreading indicator l5. This dial may be protected by a transparent covering, as the cellu- 1o loid sheet IS.

The main tuning condenser I! has projecting therefrom a rotatable member or shaft l8 by which'it is driven, this shaft projecting through the center of the dial H and having the indicator 15 I4 rigidly mounted thereon, as by a set screw IE3. Surrounding the shaft I8 at its outer extremity, and passing through the dial II is an annular member or intermediate transmission member 20. This intermediate member is freely 20 rotatable both with respect to the shaft and to the dial, and has the indicator [5 rigidly mounted thereon at its outer extremity.

Immediately below the dial, a shaft 2! is provided, this shaft extending without the panel H] 25 and having on its outer end a manually operating knob 22, which knob is removably fastened thereto, as by a set screw 23. The shaft 2| is supported at its inner end by a bearing 24 mounted on the chassis 25 of the receiving set, and-at its 30 outer end by a sleeve 26. The sleeve 26 extends through the panel 10, and has at its outer end,

a second manual operating knob 21 attached thereto,.as by a set screw 28. This sleeve 26 is adapted to rotate and to have free longitudinal 3 movement, both with respect to the shaft 2| and to the panel Ill.

The shaft 2| has rigidly mounted thereon a small friction disk 29 engaging a larger friction disk 30 at the point 3|, said larger friction disk 40 being rigidly attached to the shaft l8, as by a set screw 32. In the particular embodiment illustrated here, a ratio of about 6 to l is obtained bythe use of these two friction disks 29 and 30. Conventional or normal operation of the main 45 condenser shaft I 8 is obtained through manual rotation of the knob 22. Rotation of the knob 22 drives the disk 29 through the shaft 2|, effects rotation of the disk 39, and thus tunes the set through rotation of the main condenser.

The sleeve 26 has rigidly attached thereto a friction disk 33 which disk cooperates with a larger friction disk 34 through frictional contact This largerdisk 34 is rigidly mounted on the intermediate transmission memthe knob 2'! and the condenser shaft l8.

This large disk 3'! is mounted on the sleeve 26 and is freely rotatable with respect thereto. The

disk 37 has rigidly attached thereto spring grip I members or clips 39 adapted to yieldingly engage a clutch member as rigidly mounted on the shaft 2|. The disk 3'! and its clips 39, although freely rotatable with respect to the sleeve 26, are so mounted thereon that longitudinal movement of the sleeve effects a similar movement of the clips 39. Manually achieved longitudinal movement of the sleeve 26 thus serves to force the clips 39 into engagement with the clutch member 46. or to disengage them therefrom.

When conventional operation is desired, the mechanism is in the position illustrated in Fig. 2. It will be noted that the clips 39 are disengaged from the clutch member 0 and rotation of the knob 27 will have no effect thereon. In this position, rotation of the condenser is achieved through manual operation of the knob 22 which transmits motion through the shaft 2i, the disk 29, the disk 36 and the shaft [8 to the condenser plates. When the mechanism is in this position, the indicator I4 revolves upon operation of the knob 22, and indicates the relative setting of the condenser plates. The indicator l5, however, does not revolve since no motion is being transmitted to the intermediate member 2!]. When band-spreading is desired, the knob 21 is pushed in closer to the panel 56, which motion is transmitted by the sleeve 26 to the clips 39 and achieves engagement between them and the clutch member 40. Rotation of the knob 23 is then transmitted through the sleeve 26, the small disk 33 and the large disk 34 to the intermediate member 23. Since the intermediate member 20 is now in operation, the smaller indicator I5 will revolve, and thus indicate that the band-spreading mechanism is in operation. From the intermediate member 26 the drive will be transmitted through the small disk 35, the large disk 3! and the clips 39 to the clutch member t9, whereby rotation of the shaft 2! will be effected. Rotation of the shaft 2! again drives the condenser shaft l8 through the medium of the small disk 29 and the large disk 3B. It will be noted that when the band-spreading mechanism is operated, a triple reduction is achieved in the drive between One reduction is achieved by the disks 33 and 34, another by the disks 36 and 37, and the third by the disks 29 and 38. A very low ratio of manual movement to condenser movement is thus achieved, resulting in a band-spreading effect. Since the indicator i5 is mounted on the intermediate member, and not on the condenser shaft IS, the condenser shaft rotates at a reduced ratio with respect to the rotation of the indicator I5.

This reduced ratio is achieved through the second and third reduction means in this particular embodiment. r

The dial Il may have its outer portion calibrated arbitrarily, by kilocycles, or by wave length. In any event, certain bands of the spectrum will be found on certain portions of this dial. Should a listener desire to tune in on stations in the 49 meter band, for example, he would, through 7 use of the manual knob 22, set the main indicator M to a position on the dial corresponding to the approximate center of the 49 meter band. He would then pushin the knob 21 and tune thereafter with that knob, thus achieving a bandspreading action indicated on the inner portion of the dial by the small indicator l5. Since it is desirable that the band-spreading action be effective both above and below the initial setting of 5 the indicator l4, it is preferable that the small indicator !5 be set at approximately the center of its scale before the clutch means is engaged through the pushing in of the knob 21. When it is desired to return to conventional operation, or 1 to shift to another band in the spectrum, the knob 2'! is pulled out and operation is achieved through the use of the conventional knob 22.

In the particuar embodiment of the invention illustrated herewith the friction disks 34 and 31 15 are sufiiciently flexible that the sleeve 26 may be moved longitudinally to effect engagement of the clips 39 with the clutch means 40 without in any way detrimentally affecting the operativeness of the reduction drive operating through 20 those disks.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modifications. Changes, therefore, in the construction and ar- 25 rangement may be made without departing from the spirit and scope of the invention as disclosed in the appended claims, in which it is my intention to claim all novelty inherent in my invention as broadly as permissible, in view of 30 the prior art.

What I regard as new, and desire to secure by Letters Patent, is:

l. A tuning device for radio receivers, including; a rotatable member; a manual drive therefor; a second manual drive therefor, said second drive having a lower ratio than said first drive; a dial; and two indicators concentrically arranged on said dial indicating said two drives respectively. 40

2. Atuning device for radio receivers, including; a rotatable member; a manual drive thereranged on said dial indicating said two drives respectively; and means whereby one of said drives may be manually engaged or disengaged.

3. A tuning device for radio receivers, including; a shaft; a manual drive therefor; a second manual drive operating through an intermediate transmission member on said shaft; a dial concentrically arranged with respect to said shaft; an indicator on said shaft adjacent said dial; and a second indicator on said intermediate transmission member adjacent said dial.

4. Apparatus as claimed in claim 3 including means whereby one of said drives may be manually engaged or disengaged.

5. A tuning device for radio receivers, including; a shaft; indicating means comprising a dial concentric with said shaft and an indicator mounted on said shaft adjacent said dial; selectively engageable manually operable means for rotating said shaft and indicator or for rotating said shaft at a reduced speed; a second indicator to indicate the reduced speed rotation, said rotating means when rotating the shaft at a reduced speed operating said second indicator ing; a shaft; indicating means in connection with said shaftya second indicating means;

,manually operable means whereby said shaft 'may be rotated; a second manually operable means; reduction-drive means; and clutch means whereby said second manually operable means is engaged through said reduction-drive means to said shaft.

'7. Apparatus as claimed in claim 6 wherein said shaft is rotated at a reduced speed with respect to said second indicating means.

8. A tuning device for radio receivers, including; a rotatable member; a dial concentric therewith; means for rotating said rotatable member; an indicator adjacent said dial showing the rotation of said rotatable member; a second indicatorconcentrically mounted on said dial, said indicator being stationary when said means is operative; and means whereby said second indicator may be rotated and said member may be simultaneously rotated at a reduced speed .with respect to said second indicator.

9. A tuning device for radio receivers, including; a rotatable member; a dial concentric therewith; manual means for rotating said rtatabl-e member; an indicator mounted on said member adjacent said dial; a second indicator concentrically mounted on said dial, said indicator being stationary when said means is operative; and means for rotating said second indicator whereby said member is rotated at a reduced speed with respect to said second indicator.

10. A tuning device for radio receivers, including; a shaft, a dial concentric therewith; an indicator mounted on said shaft adjacent said dial; an annular member concentrically mounted with respect to said shaft; a second indicator on said member; manually operable driving means whereby said shaft may be rotated; and a second manually operable driving means for rotating said annular member whereby said shaft is rotated at a reduced speed with respect to said second indicator.

11. A tuning device for radio receivers, including; a shaft; a dial concentric therewith; an indicator mounted on said shaft adjacent said dial; an annular member journalled on said shaft; a second indicator mounted on said member and concentric with said dial; manually operable reduction-drive means whereby said shaft may be rotated; a second manually operable reductiondrive means whereby said annular member is rotated; and means whereby rotation of said annular member rotates said shaft at a reduced speed with respect thereto.

12. A tuning device for radio receivers, including; a shaft; a dial concentric therewith; an indicator mounted on said shaft adjacent said dial; an annular member journalled on said shaft; a second indicator mounted on said member;

member.

13. Apparatus as claimed in claim 12 wherein said sleeve is slidably journalled on said second shaft whereby longitudinal movement of said sleeve effects engagement of said clutch means.

14. Apparatus as claimed in claim 12 wherein 15 said sleeve is slidably journalled on said second shaft whereby longitudinal movement of said sleeve effects engagement of said clutch means, and wherein said driving means comprises continuously engaged friction disks.

15. A tuning device for radio receivers, including; a rotatable shaft; a dial concentric therewith; an indicator mounted on said shaft adjacent said dial; manual means for rotating said shaft; an annular member rotatably mounted on said shaft; an indicator mounted on said annular member adjacent said dial; transmission means for connecting said annular -member and shaft whereby rotation of the annular member will rotate the shaft at a reduced speed; and means for rotating the annular member.

16. A tuning device for radio receivers, including; a rotatable shaft; a dial concentric therewith; an indicator mounted on said shaft adjacent said dial; a second shaft; manual means for rotating said second shaft; transmission means connecting said shafts; an annular member rotatably mounted on said first shaft; an indicator mounted on said annular member adjacent said dial; transmission means connecting said annular member to said first shaft, whereby rotation of the annular member will rotate said first shaft at a reduced speed; a sleeve rotatably mounted on the second shaft; manual means for rotating said sleeve; and transmission means connecting said sleeve and annular member.

17. Apparatus as claimed in claim 16 in which the transmission means connecting the annular member and the first shaft includes a clutch.

18. Apparatus as claimed in claim 16 in which the transmission means connecting the annular member and the first shaft includes the transmission means connecting tlre first and second 55 shafts.

JOSEPH F. RILEY.

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