Патент USA US2109674код для вставки
March 1, 1938. J_ |_. McWEENY RADIO APPARATUS Filed NOV. 26, 1937 (1i, 7 2,109,674 Patented Mar. 1, 1938 2,109,674 UNETED STATES PATENT OFFI€E 2,109,674 RADIO APPARATUS John L. McWeeny, Chicago, Ill. Application November 26, 1937, Serial No. 176,403 5 Claims. (Cl. 116—124.1) My invention relates to radio receivers and par ticularly to means intended for use to bring about by reference to the accompanying drawing, in which; accurate indication of the tuning of such re ceivers. Fig. 1 is the side elevation of apparatus con 5 Many elements enter into the manufacture of structed in accordance with my invention; Fig. 2 is a plan view thereof; a radio chassis that tend to prevent any cer Fig. 3 is a sectional view on the line 3-3 of tainty in the matter of “capacity”, and this un Fig. 2; and certainty is increased where, as at present, many Fig. 4 is a sectional View on the line 4-4 of receiving sets are constructed to pick up fre Fig. 3. 10 quencies over a wide range; in other words, so In the drawing I have illustrated the essential called all wave receivers. This variation, notwithstanding the accuracy portions of a radio chassis including ~a base ID, of machine-made products, occurs principally in a variable condenser ll, adjusted by a tuning the condensers and although they are carefully knob l2 and having a shaft l3. Connected by 15 designed for a uniform minimum and maximum capacity, it seems mechanically impossible to produce exact duplicates, either throughout the range or at individual points. Furthermore, there is a known variation of ca 20 pacity from newto used conditions. Tempera ture, bearing wear, the relieving of internal stresses, etc., cause changes over a period of time. The same remarks apply to the inductance ele ments; temperature and moisture serve to cause 25 variations in the electric eifect which are re?ected in the tuning of the instrument. In the commercial production of radio receiv ing sets, it is, from a practical standpoint, im possible to individually calibrate each set in order 30 that the indicating means shall correspond ex actly with the tuning means, practically all sets being delivered from the assembly line with an adjustment that is approximately correct but gears id to the shaft l3 are a pair of cams l5—l6 mounted on a common shaft H. The cams are constructed to provide lateral ?anges serving as 15 the active faces of the cams, the ?anges being composed of a soft and readily bendable mate rial. Thus the cam contours may be slightly changed by the use of a pair of pliers or some other suitable tool in order to compensate for variations in the tuning indication. While I have shown but two cams, one for each of two broad cast bands, it will be understood that additional cams may be provided for each band in the design 25 of the apparatus. The indicating means may be any one of a number of types, the one shown being merely a pointer or ?nger I8 mounted for oscillation over a dial I9. The pointer is carried by a shaft 20 that is splined as at 2| to permit the rearward portion 22 to be reciprocated. A pair of pinions 23-24 are mounted on the shaft and are selec which may in adjacent sets vary in the indication tively engaged with the shaft through the spring 35 of the same station as much as 5 kc. and, as lugs shown in Figs. 3 and 4. In other words, the shaft 22 carries a pair of spaced plates 25-26 held apart by springs 21 and ?xed in position by the cross pin 28. The pinions 23—24 are notched as shown in Fig. 3 and the spring lugs are caused above stated, after the passage of time, this Var iation may be greater or less. The correction of the indicating means as ap 0 plied to one broadcast band may be accomplished with relative simplicity, but such corrections when applied to another broadcast band would, un fortunately, result in wide variations from ac , curate indication. I have, therefore, provided 15 each broadcast band with an individual element in the connection between the tuning device and the indicator, each of said elements being capa ble of adjustment for accurate calibration. Thus, if desired in a more expensive set, each broad ;0 cast band may be separately and accurately cali brated relative to a single indicating device. Fur thermore, after the passage of time and the con sequent readjustment of electrical values, the calibrations may be corrected where required. 5 The invention will be more readily understood to engage one or the other of the pinions by ax ial movement of the shaft 22. This is brought about through the bell crank 29 pivoted at 30 on a bracket 3| and oscillated through a link 32, rocker 33 and link 34, joined to the shaft 35 that operates the band switch 36. Thus, through the medium of the knob 31 connected to the shaft 35, the band switch may be shifted and, at the same time, the pinion 23 or 24 is connected to the shaft of the tuning indicator. Racks 38—39 are mounted for sliding movement in a guide piece 40, the racks having rollers on their ends that engage the active surfaces of the ?anges on the cams |5-—|6. In the more inexpensive receiving sets, it may be satisfactory to provide merely for correction 55 2 2,109,674 of the tuning of the main broadcast band in tation therewith, the cam having a deformable ?ange constituting its active surface, whereby to which case only one cam with its bendable ?ange enable correction of individual frequencies. will be provided. If, however, a plurality ‘of bands are to be corrected as to their indications, then a, plurality of cams and a suitable selecting means should be provided as shown. By use of the described apparatus, an accurate indication may 3. In radio receiving apparatus, the combina tion of tuning means, indicating means and band selecting means, a connection between the tuning means and indicating means, a plurality of cams in said connection, said cams having active sur be secured at any time that the indication is in faces capable of variation and means operated correct, it being assumed, of course, that the by said band selecting means for selecting the 10 cam contour will be manufactured as closely as cam and connecting to the indicating means the 10 possible to the predicted capacity of the particu-' cam intended for use with the individual band. lar design. 4. In combination, tuning means capable of Wherever in the speci?cation and claims ref variation to receive frequencies in different bands erence is made to a cam having a bendable active and indicating means, connections therebetween 15 portion, it should be understood that I intend to for effecting movement in unison, said connec 15 comprehend by such term any cam capable of tions including a plurality of cams adapted to be being deformed or changed as to local points on selectively operatively connected, manually oper its active surface. ated means for selecting the cam corresponding I claim: to a particular band and means on said cams 1. In radio receiving apparatus the combina permitting adjustment of local points on the 20 tion of tuning and indicating means, connections active surfaces whereby to enable correction of including a rotatable cam between the tuning and indicating means said cam having an in variable connection to the tuning means for ro 25 tation therewith, the cam having its active sur face capable of local variation whereby to cor rect the indication of individual frequencies. 2. In radio receiving apparatus the combina tion of tuning and indicating means, connections 30 including a rotatable cam between the tuning cam having an in and indicating means said ' variable connection to the tuning means for ro the indications transmitted thereby. 5. In combination, tuning means and indicat ing means and connections therebetween, said 251 connections including a plurality of cams, racks reciprocated by said cams, a shaft for operating the indicating means, pinions on the shaft en gaging said racks, a band switch and means op erated by the band switch for selectively engag— 30 ing said pinions with said shaft. 7 JOHN L. McWEENY.