Патент USA US2297389код для вставки
Sept. 29, 1942. K. BRANDHOLT 2,297,339 DRIVE FOR ELECTRIC TUNING MEANS -Filed July 29, 1939 fm/enfar: Kurz‘ Brcmdholt by Patented Sept. 29, 1942 ~ * 2,297,389‘ UNITED STATES PATENT OFFICE 2,297,389 DRIVE FOR ELECTRIC TUNING MEANS Kurt Brandholt, Berlin, Germany; vested in the Alien Property Custodian Application July 29, 1939, Serial No. 287,193 In Germany August 3, 1938 5 Claims. Certain difficulties are encountered in the tun ing methods employed in very large radio sets, especially in those using coil tuning. Such sets, especially receivers, are equipped with a great number of tuning means with the consequence that in order to tune the apparatus many coils must be adjusted. This large number includes many coils which to be tuned must be turned. This operation involves a succession of harmful (Cl. 250-11) translated by a Geneva movement 12 through a cam Hi to goniometer control contacts [3. Driv ing the coil-drum in conjunction with the range control of the goniometer occurs only when the elliptical shaped gear 5 is turned through 360 degrees. As the illustration shows the gear train begins with a large gear ratio. In this position it is able to exert a large torque which is a factor important in turning the drum out of a ratchet mechanical jolts. These jolts in particular affect 10 setting. The gears change their transmission ratio from small to large, and the drum after un the tubes in which mechanical vibrations are ratcheting enters into the next sphere of opera necessarily set up in the electrodes. Such vibra tion. The momentum of the drum is also used at tions have a destructive effect on tube life as the same time for operating the goniometer con well as altering its electrical properties, for in response to such a change the tube fades out for 15 trol contact, and in a reverse operation this acts as a brake upon the drum. As the drum nears a while after adjustment so that the set will not its new position the gear ratio between 5 and 4 operate normally again until a certain period of time has elapsed. This disadvantage is overcome by the use of the present invention. It will be assumed that the coil drum which serves for tuning adjust ments is set in motion by a tuning operation. This operation is to be effected by a gear train, which has a variable transmission ratio, which again becomes large tending to slow down the coil drum so that a shock is not transmitted to the radio set. A further feature of the invention is that the contacts ‘I are removed from the drum until a setting is made. This is accomplished with the ratchet arm 9, which lifts the contact supports 8 so that the contacts are removed by the strength may, for example, be accomplished by elliptical of their own springs. This arrangement thus or other odd-shaped gears; and it is so designed avoids contact wear due to sliding friction. that by a change of the transmission ratio from What is claimed is: step-down to step-up to step-down position again 1. A radio apparatus employing coils for tun the drum reaches a position of rest, the momen tum acquired by the drum while the high gear ° ing, comprising carrier means carrying a plu rality of coils, adjusting means for moving said ratio is effective being gradually reduced as the carrier means into different positions to render a effective gear ratio becomes lower. desired one of said coils effective, said adjusting My invention will be more fully understood means comprising a drive mechanism for rotat when considered in conjunction with the follow ing description and drawing, of which the ?gure 35 ing said carrier means, and eccentrically mounted rotary control means operative to render said shows a preferred embodiment of the invention. rotary movement slow upon initiation of rota In this illustration a coil-drum I carrying a plu tion, more rapid during an intermediate portion rality of coils 20A—20D is shown to be geared of its rotation and slow again upon its approach through a gear train 2, 3, 4, 5, and a toothed disc to said adjusted position. 6 operates to apply contacts ‘I to the di?erent 2. In radio apparatus as in claim 1, wherein coils for different positions of the drum, in the said last named means comprises an elliptical desired circuit such as the tuning condenser. gear train to effect a gear ratio variation from These contacts ‘I can be controlled by an insu step-up to step-down and back again to step-up lated spring contact support 8. Tension from 45 by one control operation. the spring l0 forces a ratchet arm 9 to follow 3. In radio apparatus employing coils for the recesses of the disc 6. tuning and contacts for connecting such coils to At the same time as this operation is being external circuits, mechanical means for adjust effected, a change is likewise being made from ing said tuning coils with a variable transmission one goniometer range to another by switch 13 ratio varying from low ratio, to higher ratio, to controlling the circuit for goniometers G1 and lower ratio for each adjustment, insulated spring G2. By this switching arrangement the fre contact supports controlled by said mechanical quency range of the goniometers may be brought adjusting means and means for raising said con into suitable relation with the circuit tuned by tacts during said adjustment. the coils 2UA--20D. This other change is initi 4. In ratio apparatus according to claim 3, ated in a gear 2 meshing another gear I I, is then 55 2 _ 2,297,389 wherein said last named means comprises ratchet means operatively associated With the said coils to effect the said control. 5. In radio apparatus employing coils for tun ing, and goniometer circuits, mechanical means for adjusting said tuning coils with a variable transmission ratio which varies from low, to higher, to low during an adjustment, means such as a Geneva movement operatively associated with the said mechanical means for alternately rendering said goniometer circuits e?ective and ineffective, and means for utilizing the momen tum of the said coils generated during adjust ment to facilitate operation of said Geneva movement. KURT BRANDHOLT.