US2316916A - Tuning indicator device - Google Patents

Description

April 20, 1943.

A. T. VOSSEN 2,316,916

TUNING INDICATOR DEVICE Filed Feb. 29, 1940 /4m /6m 2001 '1 25m 30m TUNING ll'l l'l l'l l'l l'll pm 30m l' I BANDSPREAD L DIAL 2 BANDSPREAD INVENTOR'. ARNOLD 72 l/OSSEN A TTORNE Y.

UNITED STATES PATENT OFFICE TUNING INDICATOR DEVICE Arnold '1. Vossen, Eindhoven, Netherlands, assignor to Radio Corporation of America, a corporation of Delaware Application February 29, 1940, Serial No. 321,412

In the Netherlands July 29, 1939 3 Claims.

This invention relates to a wireless receiving set comprising a coarse and a fine adjustment center of the wave band associated with each of these stations.

tuning device, the latter permitting of spreading Now, the invention has for its object to prowave bands. This so-called band spreading is vide a device enabling the user of the wireless primarily used in the short-wave region in which 5 receiving set to effect accurate tuning to a given the stations are assembled in a number of wave po nt in a wave band, for exampl to the center bands and in which the stations comprised in the of the wave band, by means of the coarse adsame band are closely adjacent each other on justment tuning device. A wireless receiving set the tuning dial. Generally, the same tuning according to the invention is haracterized in that member as that by means of which the long and the attainment of that given point in a wave band medium wave ranges are attended also serves to in which tuning to a given wave length has to be cover the short-wave range but in this latter ffected by means of the fine adjustment tuning range due to the stations being in close proxdevice is m k w y a lling device 01 imity to each other it is very diflicult to tune to Hating y Optical meansany station comprised in any of the bands by In one embodiment of the invention th movm ans of this tuning member which as regards able part of the coarse adjustment tuning device this range is of coarse adjustment. Now, by using has coupled to it one or more contacts adap ed band spreading, that is to say by passing over to cooperate with one or more contacts arranged from the coarse adjustment tuning device to a in the set in a stationary manner, the arr n fine adjustment tuning device, it is nevertheless ment being such that upon attainment of a given possible to tune the set readily and to a sufpoint, e. g., th center of a wave band capable ficiently accurate extent to the short wave staof being spread by means of the fine adjustment tions. According to a well known method of band tuning device, an electrical circuit is opened or spreading a small variable condenser is connectclosed so that the signalling device is set into ed in parallel with each of the tuning circuits. operation. As mentioned before, the coarse ad- As an alternative, band spreading may be objustment tuning device may be constituted either tained by means of a variable inductance inby a variable inductance or by a condenser. Accluded in'each of the tuning circuits. In the cording to the invention, when use is made in said cases the coarse adjustment tuning device the wireless receiving set of a variable condenser may be constituted either by a tuning condenser which may be either a rotary condenser or a or by a variable inductance. sliding-electrode condenser, the movable contacts In order that it may be possible to tune the set may be coupled to the shaft of the condenser.

by means of the fine adjustment tuning device to According to the invention, the wireless receiva station comprised in any of the wave bands ing set may be constructed in various ways. In to be spread it is therefore sufficient to tune in one embodiment of the invention one contact for to the proximity of the station by means of the each wave band is arranged so as to be stationcoarse adjustment tuning device, after which acary relatively to the shaft of the coarse adjustcurate tuning to the station can be attained by ment tuning device, said contact cooperating with means of the fine adjustment tuning device. a single contact arranged in the set in a station- Since for the purpose of tuning to a short wave ary manner. It is, however, also possible for station the user of the wireless receiving set genthe contacts associated with the wave bands to be erally disposes of a tuning dial associated with arranged in the set in a stationary manner and the fine adjustment tuning device it is essential to cause them to cooperate with one contact arin order to enable continuous use of this dial that ranged in a stationary manner in relation to the the adjustment of the fine adjustment tuning de- 4 shaft of the coarse adjustment tuning device.

vice should always be identical whenever tuning In a further embodiment of the invention the is effected to the said station. This means that contacts cooperating with each other may be conin this case it is also necessary that the coarse stituted by a pair of contacts on the one hand adjustment tuning device should always effect the and a single contact on the other hand. The same adjustment when the set is being tuned to nature of the cooperation depends on the conthe same station. This also applies to the other struction and the arrangement of the said constations comprised in the various wave bands. tacts. The construction and the arran It is customary to choose the adjustment or the may be such, for example, that when the coarse coarse adjustment tuning device for each of the adjustment tuning device; is tuned to the center short wave stations So as to coincide with the 0f a wave band the two contacts of the pair of this case they are adapted to cooperate with the contact arranged in the set in a stationary manner. It is also possible to provide a single con.- tact for each wave band to be spread, the contacts being in this case adapted to cooperate with one pair of contacts. In this case, the pair of contacts may, as before, be coupled similarly to the method hereinbefore described; forthepairs of contacts, to the movable part of the. tuning member or they may be arranged in the setina stationary manner. The same remark applies to the contacts cpcretinew h re n ice tacts. 7

According to the invention, wherg-the. .vwireless receivingset is furnished with Va rotary con denser that acts as the; coarse adjustment tuningdevice the sha ft of thc ,rotarycondenser. may carry a disc ordrum; which, on itsperiphery, carries. a pairof; contacts for each ofthe wave bands to bespread; a contact-arranged in the set in a stationary-manner bearing on the periphery of the disc or; drum, the arrangement being such that'when the; condenser is tuned, for; example, to the center-oi a wave. band the contact-s of the pair of contacts associated-with this wave band are shun b h con ac arranged he cti a, stationary 1 18621151..

A suiable; o ica i al in .dc iccmeyrb c taincd y. eans f: on r more ources of. i i t on. The si na which se v n. 11911; ettainment of a iv npo n n awar hammer be the sudden illumination or theextinguishment ofv an incandescent lamp, the sim ltaneous operation: of; two lamps, .cthcrno sib itic e ng. 2 precluded;

Acccrdine'tc. the in ntion, in t ast d c ssed fcrm of c nstructio of; a wir e s r ceiving set according to the invention, in which consequently a dis r drum. arr s airs. o contactsequalin number to thenumber of wave bands. to, be spread and; capable of cooperating successively With a. contact ar an ed iihe s in a stationary manner, the signalling device may be constructed as.fo1lQW f the 99m? arranged in the set in a stationary manner is y c ed t on of th contacts c Pa r of contacts, an electrical circuit is closed which includes a source of illuminationgiving oii a given color, and if the contact arranged in the set in astationary manner is only connected to the other contactof the pair of contacts a circuit is closed which includes a source of illumination emitting the complementary color ofthe color of the first-mentioned source of light, whereas in the case of the pair of contactsbeing shunted by the contact arranged in the set in a stationary manner both circuits are closed.

If one of the sources of light gives off, for example, red light and the other source of illumination green light, both sources of lightwill give off light in the case of both contacts of a pair of contacts being shunted by the contact arranged in the set in a stationary manner. If the light of both sources of illumination is thrown on to a screen this will be illuminated white.

In one preferred embodiment of the wireless receiving set according to the invention a contact cooperating with a pair of contacts and adapted to move relatively thereto cooperates when the coarse adjustment tuning device has arrived at one end of a wave band, with one of. the ends, remote from each other, of the contacts of this pair of contacts. In the embodiment described hereinbefore one of the sources of light, for example the red one, will operate upon a wave band being entered into, whereas this source of illumination extinguishes on the Wave band being left on the same side. The entering into or leaving of the wave band on the other side results in the other source of illumination, inthis instance consequently the green one, starting to operate or extinguishing respec- In order that the invention may be clearly understocd and readily carried into effect it will now be described more fully with reference to the accompanying drawing, in which F .1- 1; h two i ad al' t e w re e s receiving set comprising a coarse.- and. a fine ad.- justment tuning device Fig 2 shows a tuning circuit of the wireless receiving set.

Figs. 3 and 4 show two different positions. of the. condenser shaft which has coupled tolfit a number of pairs of contacts adapted tocooperate with a contact arranged in the, setina. stationary manner.

Fig. 5 diagrammatically shows thecontact clevice and the signalling device,attendedtherebyl Figs, 6A, B, Cand Q showlvarlious positions of th ccn aci a r d n h e n" a s t a manner relativelyto-a pair of. cofitactfsfconpled tcith e condenser shaft.

Big 7 diagrammaticallyshows a part of. the signalling-device. 7 L 1 The tuning dial I shown in, Fig, 1 comprises five waye bands'viz. the 14 meter, 16. met-trim meter. time}: @nd' 3Q fi an s, her of s ati ns say 2 1' cmb d iii cash he e band f ew fc e ema. air.- rangement-of the stations onthe' tuning dial it is very difficult to tune'to a s'tation comprised in any-of the. wave bands in a manner similar to that; adopted in the'medium' or long wave'ba'nd. This difficulty issolved by the useofbandspread ing, One manner of bandspreading'fi i illustrated in Fig. 2. In this? figure L ne or the timing circuits of the wireless receiving set is shown to be built up from an inductance Lja variable condenser C, which generally also serves for. tuning in the medium an d long wave bands,and. a condenser C which is connected in parallel with .thiscondenser and is small. compared therewith.

The condenser 0 permits of covering the entire tuning dial I, and the condenser C of covering only a small part, but with substantially greater accuracy since in the caseoi equal deviations of the movable parts of the condensers the can denser C submits the tuning circuit to a substantially smaller variation in capacity than in the case of the condenser C. Thus a tuning dial may be provided for each wave band which. is substantially larger than the wavel'b'and. Such a tuning dial is shown in Fig. l for. the 39 meter band and designated by 2. The other spread wave bands may also be arranged on this dial but it is also possible to use aseparate f tuning dial for each spread wave band. r nners a given station lying, for example, in the. 301 neter band the followingprocess is adopted. By means of the tuning condenser C the set is tuned to the wave band that contains the desired station. Since the tuning dial 2 is rated at a given tuning of the condenser C in the wave band it is necessary for enabling the tuning dial 2 to be used that the condenser C should be retuned accurately to the same point in the wave band. Generally, the center of the wave band is taken for such point. Next, by means of the fine adjustment condenser C the set can be tuned to the desired station which is indicated on the tuning dial 2. If, however, the condenser C were tuned slightly to the side of the correct tuning position in the wave band, the desired station, if it can be received at all, will not longer coincide with the indication on the tuning dial 2.

According to the invention, in order to enable the user of the wireless receiving set to tune the coarse adjustment tuning device, that is to say the condenser C in the case discussed here, correctly in an easy and accurate manner, provision is made of a signalling device one form of construction of which will be set out by reference to the Figs. 3, 4, 5, 6' and '7.

The shaft 3 (Figs. 3 and 4) of the rotary condenser, which is constructed as a coarse adjustment tuning device, has fast on it an insulating disc 4 carrying at its periphery five pairs of contacts each comprising the contacts a and b. These pairs of contacts are designated by Mm, I6m, 23m, 25m and 30m. A contact 5 constructed as a roller supported in the carrier 6 is mounted. in the set in a stationary manner. This roller is forced into contact with the periphery of the disc 4 by a compression spring I. The pairs of contacts I4, I5, 20, 25 and 30 are distributed in such manner along the circumference of the disc 4 that when they cooperate with the contact roller 5 the set is tuned in the I4 meter, I6 meter, meter, meter and meter bands respectively. The contacts a and b of each pair of contacts constitute the limbs of a V which in this form of construction form a very obtuse angle with each other. In Fig. 6 several positions of the contact roller 5 relative to the disc and one pair of contacts a, b are shown diagrammatically, said positions being successively obtained whenin Fig. 3 the condenser shaft 3 is rotated in the direction shown by the arrow. In Fig. 6A and also in Fig. 3 the roller 5 bears on the circumference of the disc 4. In Fig. 6B the roller 5 has engaged the contact I). In Fig. 6C, similarly to Fig. 4, the roller 5 is connected to both contacts a and b, whereas in Fig. 6D the roller 5 engages with the contact a alone.

For each pair of contacts it is, therefore, possible to indicate the position in which both contacts a, b contact with the roller 5. is a sharply bounded position this is taken advantage of to make known the attainment of e. g. the center of the wave band associated with the pair of contacts.

Fig. 5 diagrammatically shows the contact device a, b, 5 and the signalling device attended thereby, The signalling device comprises two sources of illumination 6 and I of which the source of illumination 6 can give off red light, and the other source of light I can give off a complementary color, i. e.. green light. The source or" light 6 is connected to one end of the secondary 3 of the transformer and to the a contact of the pairs of contacts. The source of light I is connected to the other end of the winding 6 and to the b contact of the pairs of contacts. The contact roller 5 is connected to the center of the winding 8. Now, when the contact Since this roller 5 is connected to the la contact alone, only the electric circuit which includes the source of light 6 is closed. This source of light thus radiates red light. If the contactroller 5 contacts with the I) contact alone, only the circuit for the source of light 1 is closed. This is consequently made known by radiation of green light. If the center of a wave band is reached the contact roller 5 engages with both contacts a, b with the result that the circuits of both lamps are closed and consequently both red and green light are radiated. If as shown in Fig. '7 the two sources of illumination 6 and I are arranged at the back of a ground glass 9, this glass will appear illuminated white on the front side. If tuning is effected by means of the coarse adjustment tuning condenser C but slightly by the side of the center of the wave band either the source of light 6 (red) or the source of light] (green) will burn. Thus, the user has got an accurate-indication when the position of the coarse adjustment tuning device must occupy, to pass over to band spreading by means of the fine adjustment tuning device, is reached. Those skilled in the art are fully aware of the manner of connecting each pair of contacts ab into parallel with light sources 6 and I so that as the disc 4 rotates roller 5 will successively close the signal circuits as explained in connection with Fig. 5.

In addition, according to the invention on entering into a wave band or leaving it by means of the coarse adjustment tuning device the user of the set may also obtain an indication. In the form of construction shown in Fig. 3 et seq., the a and 1) contacts of each pair of contacts are constructed for this purpose in such manner that when the tuning condenser C is tuned to one or to the other of the ends of a wave band, for example the 30 meter wave band, the contact roller 5 engages the end a or the end b, shown in Fig. 3, of the contacts a and b of the pair of contacts 30. In this case either the red source of light 6 or the green source of light 'I will,

therefore, burn. At the moment when the wave band is left on one or on the other side the contact roller 5 will therefore also leave the a contact at the end a or the b contact at the end 1; so that the source of light 6 or I respectively extinguishes.

What I claim is:

1. In a multi-band receiver of the type having a main reactor which is continuously variable for tuning the receiver through at least a plurality of high frequency bands and which is adjustable to a single predetermined position in each of said high frequency bands, said positions being diiTerent for said several bands, and an auxiliary reactor continuously variable to tune the receiver through each of said high frequency bands and for effecting band spread in each band, means for effecting substantially accurate adjustment of the main reactor to said predetermined positions and for visually indicating the same, comprising a member movable with the main reactor, a plurality of pairs of closely spaced contacts, one pair for each predetermined position, carried by said member, said contact pairs being spaced apart in the same angular relation as the predetermined positions of the main reactor, a normally open circuit including a visual indicator individually connected to each contact of said pairs, and a fixed contact disposed in the path of the movable contacts adapted upon varying the main reactor to successively close first one, then both and finally the other of each oi said normally. open pairs of circuits whereby 2. In a radio recelvingapparatus, atuningvrea actor. and acontrol shaft therefor, manually operatedrneans for actuating. saidflshaft, and means to e fiect accurate adjustment of Saddamactor. to. a desired. position and to visually indicate said. accurate adjustment and also positions adjacent thereto, said means, compris-v ing amemloer in the form of a disc movable with the control shaft, a pair'of spaced'contacts carried ina peripheral depression of the discmeme 1361f, anormallyopen circuitincludinga light sources individually Connected toil each of said contacts, anda relatively. fixed contact roller constructed and arranged toride on the disc periphery upon. operation-of the control shaft to successively close firstone, then both and finally theotherwof said normally open circuits whereby theaccurate,adjustment andrtheposition of the tunin'gfreactor one'ither side thereof are visually indicatedl 3."A multi-band radio receiver capable. of re eewa e caption, in at least a plurality ofihigh frequency,

bands. comprising; at, least one "tunable; c including'a coarse adjustment variablefcondenself' for] continuously tuning said circuitry over said several bands, means for adjusting said tuning" condenser to the mid-frequency of each highIrequency' band, a fine. adjustment variable cone denser, included in said: circuit and adjustable when, the coarse adjustment condenser is ad-l justed to one/of the mid-frequency positions to" effect band'spreading of said, tunable circuit to tune the same over the corresponding high free quency band, and, meanscooperatively related with'the.adjustingfmeans for the coarse, adjust: ment condenser for giving a, visualindication upon. adjustment of said condenser to itsmid r frequency.position,- saidmeans comprising a fizged contact, a pairo'f contacts. movable with, the

coarse adjustment condenser andsov disposed

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