US3254540A

US3254540A - Tuning apparatus

Info

Publication number: US3254540A
Application number: US387667A
Authority: US
Inventors: Orville D Thurnell
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1964-08-05
Filing date: 1964-08-05
Publication date: 1966-06-07
Anticipated expiration: 1983-06-07

Description

June 7, 1966 o. D. THURNELL 3,254,540

TUNING APPARATUS Filed Aug. 5. 1964 Inventor BY ORVILLE D. THURNELL WMMLQQL ATTYS.

United States Patent Filed Aug. 5, 1964, Ser. No. 387,667 8 Claims. (Cl. 7410.8)

This invention relates generally to wave signal tuning apparatus, and more particularly to an improved and compact tuning device which is easily calibrated.

Certain applications for wave signal tuning apparatus may require that such apparatus be compact, simple and very reliable. One such application may be where wave signal tuning apparatus is utilized for tuning an individual radio receiver proximate a passenger seat in a passenger conveyance such as a bus, train or plane. Because a given transportation company may own large numbers of conveyances, each equipped with individual receivers proximate passenger seats, maintenance costs would be undesirably high unless the tuning apparatus were very reliable in operation. Furthermore, minimum available spaced on most conveyances dictates that the apparatus be as compact as possible. In addition, where such apparatus is to be operated by individual passengers, simplicity of operation is.essential. Finally, because such apparatus may be installed in existing conveyances, installation must be possible to minimize the down time of the conveyance.

Accordingly, it is an object of this invention to provide an improved tuning device which is simple of construction, compact, and reliable in operation.

Another object of the invention is to provide wave signal tuning apparatus which is readily assembled and installed.

A feature of the invention is the provision of a rotatable indicator member having indicia thereon for tuning indication and mounted such that indicia are visible through an opening in the mounting panel. The indicator member is readily released from its driving mechanism for easy calibration.

Another feature of the invention is the provision of an indicator member driven by a pinion gear with the indicator member having crown gear teeth thereon spring biased into engagement with the pinion gear. The indicator member is manually displaceable axially against the bias of the spring to be freely rotatable for calibration.

Still another feature is the provision of a pinion gear for operating a tuner and an indicator member, which pinion gear is driven through a slip clutch by a rubber surfaced wheel in engagement with a manually turnable knurled knob.

In the drawing:

FIG. 1 is an end elevational view, partially in section, showing wave signal tuning apparatus constructed in accordance with the invention and mounted on a panel;

FIG. 2 is a side elevational view thereof, partially in section;

FIG. 3 is a bottom plan view of the tuning apparatus;

FIG. 4 is a bottom plan view similar to FIG. 3 but wherein the indicator wheel is disengaged from its driving gear; and

FIG. 5 is an exploded perspective view of a portion of the tuning apparatus of FIGS. 1-4.

In accordance with the invention, wave signal tuning apparatus is provided with a tuner drive shaft rotatable to position tuning elements. Control means for rotating the tuner drive shaft are provided and include a manually operable knurled knob which engages and drives a rubber surfaced wheel. The wheel drives a pinion gear through a slip clutch. The pinion gear has an axis of rotation "Ice substantiallyperpendicular to the drive shaft. A crown gear engages the pinion gear and is drivingly connected to and coaxial with the drive shaft. An indicator wheel, having indicia thereon for indicating the frequency to which the tuning elements positioned by the drive shaft are tuned, is mounted concentric with the crown gear. The indicator wheel has crown gear teeth on one edge of its outer surface and these teeth engage the pinion gear and turn the indicator wheel in a predetermined relationship to the crown gear and the drive shaft in response to rotation of the pinion gear. The indicator member is axially biased by means of a spring to hold the crown gear teeth thereon in engagement withthe pinion gear and is manually displaceable against the bias of such spring to disengage the crown gear teeth and permit free rotation of the indicator wheel for calibration.

The wave signal tuning apparatus shown in the drawing is for tuning an AM radioreceiver mounted behind a panel in a bus, proximate a passenger seat therein. The apparatus includes a tuner frame 11, which carries the usual tuning coils for the radio receiver. Frame 11 also includes a linearly displaceable core carriage 12 which carries a plurality of movable cores 13. Cores 13 extend into the coils for tuning the same according to the position of core carriage 12. Core carriage 12 is positioned by means of a worm or screw 15, which is formed integral with a tuning shaft 17. Rotation of tuning shaft 17 causes worm 15 to drive the core carriage, 12 and position the tuning slugs 13 for tuning the radio receiver. A tuner structure of the type described is disclosed in a copending application of Charles E. Lyon, Jr., Serial No. 231,060, filed October 15, 1962, now Patent 3,190,132 and assigned to the assignee of the present invention.

A mounting plate 21 is secured over one end of the tuning frame 11 and includes an opening therein through which control shaft 17 passes. Plate 21 has a right angle portion 22 thereon from which an integral arm 22a extends. The arm 22a has a control knob 23 pivotally mounted thereon. Control knob 23 extends downwardly through an opening in a frame structure 25 and protrudes through a further opening in a panel 27. Thus knob 23 may be turned manually by the finger of a passenger seated proximate the receiver.

Knob 23 is knurled on its surface and engages a rubber surfaced pinion wheel 31. Pinion wheel 31 is drivingly connected through a slip clutch comprised of plate 31a and spring 32 to pinion shaft 33. Spring32 is attached to pinion shaft 33 and engages plate 310 to provide a predetermined frictional engaging force therebetween. "A three section pinion gear 35 is mounted on shaft 33.

Shaft 33 is supported at one end by a saddle in right angle portion 22 of plate 21, and at the other end by a saddle in an outwardly extending flange 37. The shaft 33 is seated in position in the saddles by means of a spring 38, which is mounted to plate 21 and extends over shaft 33.

The section of pinion 35 furthest from wheel 31 is engaged by a crown gear 41. Crown gear 41 has an integral sleeve 41a extending therefrom which sleeve is keyed to a keyed portion 17a of control shaft 17 for driving the same. Thus, when knob 23 is rotated manually, drive shaft 17 will be rotated to position the cores 13 through the torque transmission chain comprised of knob 23, wheel 31, plate 31a, spring 32, shaft 33, pinion 35, crown gear 41 and sleeve 41a. At the ends of travel of the core carriage 12, the frictional engagement force between spring 32 and plate 31a will be overcome and although knob 23 is rotated further, no damage or binding of parts will result.

In wave signal tuning apparatus of the type shown,

compactness is a prime consideration. The previously described construction will, as may be seen, fulfill this requirement. The problem of providing adequate visual indication of the frequency to which the apparatus is tuned is also solved by the apparatus of the invention. An indicator wheel 51 is provided with indicia on the outer surface thereof for indicating the frequency to which the tuning elements or cores 13 positioned by drive shaft 17 are tuned. Wheel 51 may be of molded plastic and has a plurality of crown gear teeth 52 on one edge of its outer surface. Wheel 51 has an integral sleeve 53 at the center thereof such that Wheel 51 may be mounted coaxially wtih gear 41 and tuning shaft 17. Sleeve 53 fits over sleeve 41a and is rotatable with respect thereto. The spring 55 is secured to the end of shaft 17 and biases the wheel 51 axial-1y along shaft 17, so that crown gear 41 is held in engagement with pinion 35, and so that crown gear teeth 52 also are in engagement with pinion 35.

The ratio between the number of teeth on crown gear 41 and the number of crown gear teeth 52 on Wheel 51 is selected such that wheel 51 will make one complete revolution as core carriage 12 travels from one limit of its travel to the other due to the driving of gear 41. A workable ratio between the number of teeth on crown gear 41 and crown gear teeth 52 has been found at 20 to 95. Other ratios determined by the requirements of the system will, of course, be within the scope of the invention. The dial markings or indicia on wheel 15 are calibrated with the position of the tuning elements by first tuning the apparatus to a predetermined frequency. Wheel 51 is then drawn outwardly to the position indicated in FIG. 4 so that crown gear teeth 52 disengage from pinion 35. This permits Wheel 51 to be freely rotated with respect to the shaft 17 such that the indicia may be positioned properly. Referring to FIG. 1, it will be seen that the indicia on the surface of wheel 51 are visible through an opening 27a, formed in panel 27 for this purpose. Thus, by proper calibration, the user of the apparatus may turn knob 23 and observe the frequency to which the apparatus is tuned through opening 27a. The units may be readily calibrated at the factory when they are assembled and if some deviation occurs during shipping or final mounting into a conveyance, recalibration is easily accomplished.

Such a simple construction provides numerous advantages. The simplicity carries with it an inherent reliability, reducing maintenance cost. Because of the simplicity of construction, assembly costs are also reduced. Where string or cable type dial indicators are used, complex final assembly operations are often necessary whereas with the present invention, final assembly is very simple. Crown gear teeth 52 and the teeth of pinion gear 35 are so designed that full gear mesh will not occur. This permits full tooth engagement between the teeth of crown gear 41 and those of pinion 35 to minimize backlash. Were full engagement between both the teeth of gear 35 and the teeth 52 with pinion 35 permitted, interference problems might result. The pressure which spring 35 applies to the wheel 51 is sufficient to cause crown gear teeth 52 to hold the pinion against the slip torque applied by the clutch consisting of plate 31 and spring 32. This prevents tooth skipping which would affect the calibration of the apparatus.

It may therefore be seen that the invention provides improved wave signal tuning apparatus which is simple and compact of construction and may be readily calibrated.

What is claimed is:

1. Wave signal tuning apparatus including in combination, a tuner drive shaft rotatable to position tuning elements, control means coupled to said drive shaft for rotating the same, said control means including torque transmitting means turning in a predetermined relationship to said drive shaft, and an indicator member having an outer surface with indicia thereon for indicating the frequency to which the tuning elements positioned by said drive shaft are tuned, said indicator member having means on one edge of said outer surface thereof in engagement with said torque transmitting means and turning said indicator member in a predetermined relationship to the rotation of said drive shaft in response to rotation of said torque transmitting means, said indicator member being axial-1y displaceable to disengage from said torque transmitting means to permit said indicator member to be turned freely for calibration.

2. Wave signal tuning apparatus including in combination, a tuner drive shaft rotatable to position tuning elements, control means coupled to said drive shaft for rotating the same, said control means including a gear turning in a predetermined relationship to said drive shaft, and an indicator member having indicia thereon for indicating the frequency to which the tuning elements positioned by said drive shaft are tuned, said indicator member having gear teeth in engagement with said gear and turning said indicator member in a predetermined relationship to the rotation of said drive shaft in response to rotation of said gear, said indicator member being displaceable to disengage said gear teeth from said gear to permit said indicator member to be turned freely for calibration.

3. Wave signal tuning apparatu's including in combination, a tuner drive shaft rotatable to position tuning elements, control means for rotating said drive shaft, said control means including a first gear having an axis of rotation substantially perpendicular to said drive shaft, a second gear engaging said first gear and being drivingly connected to and coaxial with said drive shaft, an indicator member having indicia thereon for indicating the frequency to which the tuning elements positioned by said drive shaft are tuned, said indicator member being concentric with said second gear and having gear teeth about its periphery, said gear teeth being in engagement with said first gear and turning said indicator member in a predetermined relationship to said second gear and said drive shaft in response to rotation of said first gear, said indicator member being axially displaceable to disengage said gear teeth from said first gear to permit free rotation of said indicator member for calibration.

4. Wave signal tuning apparatus including in combination, a tuner drive shaft rotatable to position tuning elements, control means coupled to said drive shaft for rotating the same, said control means including a pinion gear turning in a predetermined relationship to said drive shaft, an indicator member having an outer surface with indicia thereon for indicating the frequency to which the tuning elements positioned by said drive shaft are tuned, said indicator wheel having crown gear teeth on one edge of said outer surface thereof in engagement .with said pinion gear and turning said indicator wheel in a predetermined relationship to said drive shaft in response to rotation of said pinion gear, and spring means resiliently biasing said crown gear teeth of said indicator wheel in engagement with said pinion gear, said indicator wheel being manually displaceable axially against the bias of said spring means to disengage said crown gear teeth from said pinion gear and permit said indicator wheel to rotate freely for calibration.

5. Wave signal tuning apparatus including in combination, a tuner drive shaft rotatable to position tuning elements, control means for rotating said drive shaft, said control means including a pinion gear having an axis of rotation substantially perpendicular to said drive shaft, a crown gear engaging said pinion gear and being drivingly connected to and coaxial with said drive shaft, and an indicator member having an outer surface with indicia thereon for indicating the frequency to which the tuning elements positioned by said drive shaft are tuned, said indicator member being concentric with said crown gear and having gear teeth on one edge of said outer surface thereof, said gear teeth being in engagement with said pinion gear and turning said indicator member in a predetermined relationship to said crown gear and said drive shaft in response to rotation of said pinion gear, said indicator member being displaceable to disengage said gear teeth from said pinion gear and permit free rotation of said indicator member for calibration.

6. Wave signal tuning apparatus including in combination, a tuner drive shaft rotatable to position tuning elements, control means for rotating said drive shaft, said control means including a pinion gear having an axis of rotation substantially perpendicular to said drive shaft, a crown gear engaging said pinion gear and being drivingly connected to and coaxial with said drive shaft, an indicator wheel having an outer surface with indicia thereon for indicating the frequency to which the tuning element's positioned by said drive shaft are tuned, said indicator wheel being concentric with said crown gear and having crown gear teeth on one edge of said outer surface thereof, said crown gear teeth being in engagement with said pinion gear and turning said indicator member in a predetermined relationship to said crown gear and said drive shaft in response to rotation of said pinion gear, spring means =bia'sing said indicator Wheel with said cro wn gear teeth thereon in engagement with said pinion gear, said indicator wheel being manually displalcealble axially to disengage said crown gear teeth from said pinion gear to permit free rotation of said indicator wheel for calibration.

7. Wave signal tuning apparatus including in combination, a tuner drive shaft rotatable to position tuning elements between first and second positions, control means for rotating said drive shaft, said control means including a pinion gear having an axis of rotation substantially perpendicular to said drive shaft, a crown gear engaging said pinion gear and being drivingly connected to and coaxial with said drive shaft, an indicator wheel having an outer surface with indicia thereon for indicating the frequency to which the tuning elements positioned by said drive shaft are tuned, said indicator wheel having gear teeth on one edge of said outer surface thereof in engagement with said pinion gear and turning said indicator wheel in a predetermined relationship to rotation of said drive shaft in response to rotation of said pinion gear, said indicator wheel being axially displaceable to. disengage said teeth from said pinion gear and permit said indicator member to be turned freely for calibration, a manually rotatable knurled knob for control of the tuner, a rubber surfaced pinion wheel in engagement with said knurled knob and rotatable thereby, said a slip clutch coupling said pinion wheel to said pinion gear and causing said pinion wheel to turn said pinion gear and-position the tuning elements between the first and second positions, said slip clutch permitting said pin-ion wheel to turn with respect to said pinion gear when said pinion gear is stationary at the first and second positions of the tuning elements.

8. A wave signal tuner including in combination, a tuner drive shaft rotatable to position tuning elements between first and second positions, control means for rotating said drive shaft, said control means including a first gear having an axis of rotation substantially perpendicular to said drive shaft, a second gear engaging said first gear and drivingly connected to said drive shaft, a manually rotatable knob for controlling said tuner and having a knurled periphery, a pinion wheel having a resilient periphery in engagement with said periphery of said knob to be rotatabile therebyyand means including a slip clutch coupling said pinion wheel to said first gear to cause said pinion wheel to turn said first gear and position said tuning element-s between the first and second positions, said slip clutch permitting s-aid pinion wheel to turn with respect to said first gear when said first gear is stationary at the first and second positions of the tunin-g elements and said knob is rotated.

' References Cited by the Examiner UNITED STATES PATENTS 1,601,968 10/1926 Huth 74 10.s 2,523,032 9/1950 La Flamme 74 10.s 3,106,098 10/1963 Race 74-10.s

MILTON KAUFMAN, Primary Examiner.

Claims

8. A WAVE SIGNAL TUNER INCLUDING IN COMBINATION, A TURNER DRIVE SHAFT ROTATABLE TO POSITION TUNING ELEMENTS BETWEEN FIRST AND SECOND POSITIONS, CONTROL MEANS FOR ROTATING SAID DRIVE SHAFT, SAID CONTROL MEANS INCLUDING A FIRST GEAR HAVING AN AXIS OF ROTATION SUBSTANTIALLY PERPENDICULAR TO SAID DRIVE SHAFT, A SECOND GEAR ENGAGING SAID FIRST GEAR AND DRIVINGLY CONNECTED TO SAID DRIVE SHAFT, A MANUALLY ROTATABLE KNOB FOR CONTROLLING SAID TURNER AND HAVING A KNURLED PERIPHERY, A PINION WHEEL HAVING A RESILIENT PERIPHERY IN ENGAGEMENT WITH SAID PERIPHERY OF SAID KNOB TO BE ROTATABLE THEREBY, AND MEANS INCLUDING A SLIP COUPLING SAID PINION WHEEL TO SAID FIRST GEAR TO CAUSE SAID PINION ELEMENTS BETWEEN THE FIRST AND SECOND TION AND TUNING ELEMENTS BETWEEN THE FIRST AND SECOND POSITIONS, SAID SLIP CLUTCH PERMITTING SAID PINION WHEEL TO TURN WITH RESPECT TO SAID FIRST GEAR WHEN SAID FIRST GEAR IS STATIONARY AT THE FIRST AND SECOND POSITIONS OF THE TUNING ELEMENTS AND SAID KNOB IS ROTATED.