Патент USA US2134913код для вставки
Nov. 1, 1938. A, w, EDWARDS . 2,134,913 RADIO OR LIKE RECEIVER Filed Dec. 4, 1936 (5%. 5 Sheets-Sheet l Nov. 1, 1938. A. w. EDWARDS RADIO OR LIKE RECEIVER Filed Dec. 4, 1936‘ P6 m @ x3 i4 U W 2,134,913 I 5 Sheets-Sheet 2 Nov. 1, 1938. A. w. EDWARDS 2,134,913 RADIO OR LIKE RECEIVER Filed Dec° 4', 1956 5 Sheets-Sheet 3 2,134,913 Patented Nov. 1, 1938 UNITED STATES PATENT OFFICE 2,134,913 RADIO 0R LIKE RECEIVER Arthur Wallace Edwards, Hollinwood, England, assignor to Ferranti Electric Inc., New York, N. Y. Application December 4, 1936, Serial No. 114,272 In Great Britain December 7, 1935 6 Claims. This invention relates to radio or like receivers of the type incorporating one or more band-pass ?lter stages such as, for instance, an intermediate frequency stage of a superheterodyne receiver. In receivers of this type, the wider the fre» quency band passed through the receiver, the better is the ?delity of the reproduction to the transmission being received. In order to permit the passage of a wide frequency band the re~ sponse curve of each band-pass ?lter stage should be of the double hump form; the width of fre quency band that can be passed for any given transmission being received differs according to the strength of the transmission, and conse quently the shape of the response curve also differs. It is well known that tuning of receivers under conditions of a wide response curve is dif? cult owing to there being a number of positions of the tuning apparatus for which apparently 20 similar results are obtained. It is desirable therefore to narrow the fre quency band passed through the receiver to cor respond with a response curve having a single peak before performing the tuning operation, (01. 250-20) Figure 6 is an enlarged side View of part of the coil operating mechanism. Figure 7 is an enlarged end view of said part of the coil operating mechanism, and Figure 8 is an enlarged plan view of said part of the coil operating mechanism. In carrying the invention into effect according to the form illustrated by way of example as ap plied to a superheterodyne radio receiver, I con struct the intermediate frequency transformer in li) such a manner as to have its two coils a, b mount- ed coaxially, the coil or being ?xed rigidly to a tubular member 0 and the coil 12 being mounted upon a sleeve 07. capable of movement in an axial direction along the tube 0. A tube 1‘ is slidable within the tube 0 and car ries a radial pin g by which the tubes d and f are constrained to move together as one in a vertical direction; vertical slots 72. in the tube 0 through which the pin g passes are provided to present Lit) this vertical movement. A cranked rod e is piv oted to the tube J‘ and to a slotted plate 7' and is carried in ?xed forks 76 whereby rotation of a shaft 75 carrying an arm q with a pin m engag ing the slot 11 in the plate 9' effects a rise or fall 25 after which process the band Width passed is in creased to suit the transmission being received. 1 of the coil b. The shaft t is coupled to a shaft To effect this procedure it has been proposed 0 passing through the front of the cabinet (not to provide manual means for ensuring that before shown) containing the receiver, a knob p being attached to the shaft 0. the receiver can be tuned to the required trans— Associated with the shaft 0 is a ?delity con 30 mission and the coupling between the coils then increased in order to widen the frequency band trol device which comprises a notched wheel r passed through the receiver, the coupling between the two members of each band-pass ?lter stage mounted frictionally on the shaft, being held by must be decreased, with the result that the re sponse curve of the ?lter is caused to be of the The degree of friction is such that when the notched wheel 1" is held, a spring u tending to rotate the shaft t in a counterclockwise direction in Figures 3 and 4 is unable to rotate the shaft. Two pins or ?ngers v, 12’ attached rigidly to or single peak form. The object of this invention is to provide im proved or simpli?ed means for achieving such result. 40 The invention consists in a radio or like re ceiver incorporating features set out in the claims appended hereto. Referring to the accompanying diagrammatic drawings:— Figure 1 is a perspective view of part of a tuning apparatus embodying the present inven tion in one form. Figure 2 is an enlarged side view of the inter mediate frequency transformer coils and mount 50 ing thereof with part of the enclosing case broken away. Figures 3 and 4 are enlarged end views of part of the tuning and ?delity control mechanism. Figure 5 is an enlarged side view of said part of the mechanism. means of a spring washer or the like (not shown). forming part of the lower ends of two approxi mately diametrically opposite arms w, a: co-oper~ ate with the notched wheel r in such a manner that when one pin or ?nger v, o’ is in engage ment with the wheel 1", the other bears against the periphery of the wheel between two ad jacent notches. The two arms to, a: are pivoted to each other at the mid-point of each. A cam s is 45 provided in driving relationship with the shaft and adjacent to the notched wheel 1'; this cam has two approximately diametrically opposite lifts 50 y, z, the lift 2 being provided with a stop 2 at the top thereof. The ?ngers follow the cam when ever the latter rotates, riding up the lifts until the stop prevents further rotation of the cam. A subsidiary spring 3 is disposed on the pivot 4 2 2,134,913 between the two arms so as to urge both ?ngers v, 22' towards the notched wheel r. The tuning apparatus includes a spindle 5 which latter is mounted parallel to the shaft 0. Til A star wheel 6 is ?xed rigidly on this spindle. Two studs 1, 8, one attached to each of the re mote ends of the two arms referred to above, co operate with the star wheel ‘6 in such a manner that in the position shown in Figure 3 the arm £23 engaged by the ?nger v’ with the notched wheel r is also engaged by a stud with the star wheel 6, the other arm 20 being held out of engagement with the notched wheel 1' by the pin 8 engaging the star wheel 6. In operation, assuming the receiver to have been tuned to a particular station and the cou— pling between the coils a, b of the intermediate frequency transformer to have been adjusted to give a response curve suited to the station in ques tion; upon rotating the tuning spindle 5, with the object of effecting a change in the station being received, the star wheel 5 rotates therewith and on the ?rst movement the pin 1 which is in engage— ment with it is forced outwards so that the ?nger v’ on the opposite end of the arm at to which the pin 7 is attached is lifted out of engagement with the notched wheel r. Thus the notched wheel is no longer held and the spring it causes the shafts t, o to rotate into the position shown in Figure l 30 and the movable coil b of the intermediate fre quency transformer to move towards its lower most position. The cam s on the shaft 0 rotates with the shaft sufficiently for the two swell portions 1/, z to lift and retain the two ?ngers o, 2;’ out of contact with the notched wheel r, thus simultaneously preventing the pins 7, 8 on the opposite ends of the arms from contacting or re-engaging with 40 the star wheel 6. The mechanism now occupies the position shown in Figure 4. The tuning spindle 5 is now free to be rotated without actuating the arms 10, m and it may be adjusted into any desired posi tion. When the receiver has been retuned to the de sired station, the operator turns the knob 11 at tached to the shaft 0 in order to move the mova ble coil 73 nearer to the ?xed coil it until the cou pling is such as to give a response curve suited to the new station. This operation rotates the cam s in clockwise direction and allows the ?n gers to drop from the swells or lifts of the cam to contact with the notched wheel 1', e. g. as shown in Figure 3. I As soon as one or other of the two ?ngers en gages with the notched wheel the latter is ar rested and the pins 1, 8 are brought into opera tive engagement with the star wheel 6 ready for the next retuning process, but the knob p may be 60 moved to vary as desired the position of the mov ing coil 21 since the notched wheel r remains locked. The teeth of the notched wheel 1" are so shaped as to ensure that one or other ?nger v, 12’ will drop into a notch. The stop 2 on the cam 8 may be employed as an audible indicating device, the sound caused When it strikes the ?nger 2i’ acting as an indica tion to. the operator that the receiver is in its high selectivity condition. The arrangement described for enabling rota tion of the shafts to effect movement of the coil on the intermediate frequency transformer is by way of example only and does not form part of 75 the invention. Having now described my invention what I claim as new and desire to secure by Letters Pat ent is :— 1. A receiver incorporating an adjustable band pass ?lter circuit, a tuning control device, means actuated by mere rotation for tuning purposes of said tuning control device automatically reduc ing to a pre-set minimum the frequency range of responsiveness of said band-pass ?lter circuit and a further control device for subsequently in 10 creasing to any desired extent the frequency range of response. 2. A receiver as claimed in claim 1 wherein the said band-pass ?lter circuit includes rela tively movable members for varying the degree 15 of coupling and in addition there is provided as part of said means actuated by mere rotation of said tuning control device a return spring for urging the said members to adopt a position cor responding to minimum frequency range of re sponsiveness of said band-pass ?lter circuit, re taining means for preventing the said members from responding to the action of the said return spring and further means associated with said tuning control device operable to release said re taining means upon variation of the position of said tuning control device. 3. A receiver as claimed in claim 1 wherein the said band-pass ?lter circuit includes rela tively movable members for varying the degree of coupling, there is provided as part of said means actuated by mere rotation of said tuning control device a return spring for urging said members to adopt a position corresponding to minimum frequency range of responsiveness of said band-pass ?lter circuit, retaining means for 20 25 30 35 preventing the said members from responding to the action of said return spring, and further means associated with said tuning control de vice operable to release said retaining means up 40 on variation of the position of said tuning control device and wherein said retaining means include a notched wheel mounted frictionally on a shaft operatively associated with said relatively mov able members and two arms are provided having a ?nger on one end of each arm, the ?ngers being urged into engagement with said notched wheel by the action of a subsidiary spring, the arrange ment being such that when one of the pins en gages a notch the other contacts with a tooth. 4. A receiver as claimed in claim 1 having rel 50 atively movable members for varying the degree of coupling in said band-pass ?lter circuit and wherein said means actuated by mere rotation of said tuning control device include a return spring for said members, retaining means for 55 said members, releasing means for said retaining means operable by said tuning control device, said retaining means including a notched wheel mounted frictionally on a shaft operatively asso ciated with said relatively movable members, two 60 arms having a ?nger on one end of each, the ?n gers being urged into engagement with said notched wheel by a subsidiary spring, said releas ing means associated with said tuning control de 65 vice serving to release a ?nger from engagement with said notched wheel, and a cam serving to prevent engagement or re-engagement between the ?ngers and the notched wheel upon rotation of said shaft having been effected by said return 70 spring. 5. A receiver as claimed in claim 1 including as part of said means actuated by mere rotation of said tuning control device a cam, a pair of arms having ?ngers at both ends of each, a 75 2,134,913 3 notched wheel associated with one pair of ?n ?delity control shaft associated with said rela gers, a star wheel associated with the other pair of ?ngers, a cam associated with said notched wheel, a part on said cam co-operating with a tively movable members, a. notched wheel on said shaft, a star wheel associated with said tuning control device, a pair of arms having ?ngers on stop and a return spring for urging said part of the cam into engagement with the stop. 6. A receiver including in combination an ad both ends of each, the ?ngers on the opposite ends of one arm simultaneously respectively ly ing between a pair of teeth on the star wheel and engaging a notch in the notched wheel whilst the ?ngers on the opposite ends of the other arm simultaneously respectively rest upon the ex 10 justable band-pass ?lter circuit having two rela tively movable members for varying the degree 10 of coupling, a return spring for urging said members into a position corresponding to mini mum frequency range of responsiveness of said band-pass ?lter circuit, a tuning control device, a tremity of a star wheel tooth and a notched wheel tooth. ARTHUR WALLACE EDWARDS.