Патент USA US2406597код для вставки
Aug. 27, 1946.v l H1 „Us ‘ Y `2,406,597 ELECTRIC PICKUP Eiled Sept. 7, 1944" Harold T. Paus, bg ¿Vm/176 ¿Ami/M1 H is Attorneg. Patented Aug. 27, 1946 2,406,597 '_'.,UNITED STATESPATENT OFFICE ELECTRIC PICKUP Harold T. Faus, Lynn, Mass., assígnor to Gen eral Electric Company, a corporation of -New kYork Application September 7, 1944, Serial No. 553,019 6 Claims. (Cl. 17a-100.41) 1 My ‘invention relates to Vibration translating ' devices, such as phonograph pickups, and partic ularly to such devices of the electromagnetic type having movable coils. ' ' Yltis an object of my invention to provide an improved electric pickup of simple and rugged construction and‘having a moving system oi very loW- inertia. j , . ` , ; - yItis another object of my invention to provide `an ¿improved phonograph pickup having a vvibrat able stylus arm and associated coil oi very light weight and low inertia which will track inthe 2 ¿LV The details of construction of the pickup 5 are clearly shown in Figs. 2 to 5, inclusive. - The supporting head of the pickup includes a block Il] ofV rigid insulating material secured in the end of the tone arm 2 by a setscrew Il. A magnet structure l2 and a weight i3 are rigidly secured to *l theblock I0 by a screw' ld. The stylus 6 is mounted onthe core structure l2 and a ycoil l5 is secured on a nonmagnetic support i6 of alu 10 minum'or other suitable light material which is connected rigidly to thel stylus 6 for Vibration therewith. The coil l5 is provided with termi sound groove of a record with very slight pressure nals il, which are connected to the leads 9 on the stylus.~ through suitable conductors i8 secured to .the The features of my invention which I believe to 15 block l0 byvscrews I3, only one of the conductors be novel are set forth with particularity in the i8 and screws I9 being shown on the drawing. appended claims. My invention itself, however, A shield 25 enclosing the sides and bottom of both as to its organization >and method of opera~ the’ pickup and held on the tone arm 2 by a col tion, together with further objects and advan lar 2| is provided to enclose the pickup, and a tages thereof, may best be understood by refer cover 22 is secured over the front and top of the ence to the following description taken in con pickup and held in place by a screw 23. The nection with the accompanying drawing in which cover 2i! is provided with an opening 24 at its for Fig'. 1 represents a portion of a phonograph pro ward end and the stylus 6 extends beyondvthe vided with a pickup> embodying my invention; Fig. 2 is -an enlarged view, partly in section, of the pickup head shown in Fig. 1; Fig. 3 is a View, ,partly broken away, 01,1 the line 3-3 of Fig. 2; pickup through the opening 24 into position for 25 engagement with the sound track of a record. As shown in Figs. 3 ande, the magnet struc ture i2 comprises two bar magnets 25 and 26 4 is a bottom plan View of the portion of the yoked together at their top ends by a »bar 2l of pickup shownA in Fig. 3; and Fig. 5 is an enlarged 30 magnetic material. A block 2S of brass or other sectional View of the stylus arm and coil assem suitable nonmagnetic material is soldered or otherwise rigidly secured within the magnetic Referring now .to the drawing, the phono structure in engagement with the magnets 25 and graph in Fig, 1 comprises a turntable `l and a 25 and the yoke 27. The lower ends of the mag tone arm 2 both of which are mounted on a suit, nets 25 and 26 are provided with pole pieces 29 35 able supporting structure a portion of which is and 30, respectively, which are spaced apart indicated at 3, the turntable being driven in the at the lower end of the structure and have faces usual manner by a motor mounted Awithin the of .circular cross section, as indicated in Fig. 4. supporting structure. The tone arm 2 is pivot The block 23 is somewhat shorter than the bar ally mounted on a bracket 4 rotatably mounted 40 magnets and a core 3l of magnetic material is in the support 3, and a pickup 5 is mounted secured in the block 28 in a recess 32 as indi bly of the pickup. onthe arm 2 in mounted on the track of a record of the tone arm a position such that a stylus 6 pickup may engage the sound 'l on the turntable. The weight cated in Fig. 5. The stylus 3 and coil l5 are re siliently mounted on the core 3|, the coil l5 being concentric with the faces of the pole pieces 29 and pickup to the right of the 45 and 30.. The details of construction of the stylus bracket 4 is balanced by a suitable counterweight arm and coil assembly are clearly shown in Fig. 5. B to the left of the bracket 4 so that a very small The stylus 5 is mounted in a sleeve 33 whichvhas unbalanced weight remains for holding the stylus a pin 34r projecting upwardly from the other end 6 on the record. Electric voltage variations pro-thereof. The sleeve 33 is provided with an annu duced by the pickup 5 in accordance with vibra 50 lar shoulder 35-and the coil support IS is securely tions of the stylus 6 are amplified by suitable ap mounted on the sleeve 33 in engagement with -paratus (not shown) which is connected to the the shoulder 35. The stylus arm thus comprises pickup through Wire leads 9 the ends of which the pin 34 and the sleeve 33 with the stylus 6 have been indicated as entering the interior of supported in the lower end of the sleeve. The the structure 3 through the base of the bracket stylus is preferably a sapphire or other suitable 2,406,597 and means including a coil spaced from and sur jewel. The magnetic core 3l is of circular cross section and has an enlarged portion 36 mounted rounding said core between said pole pieces and supported solely by said stylus arm for trans lating into electrical variations the vibrations of said stylus. in alignment with the pole pieces 29 and 30 and equally spaced from the pole pieces. The core 3| is provided with a downwardly opening central 2. An electric pickup or the like comprising a supporting head, a permanent magnet structure mounted on said head and providing two spaced recess 31, and a block 38 of rubber or other suit able resilient material is positioned in the re cess, and the pin 34 is pressed into a central open pole pieces, a magnetic core supported on said ing 39 in the block 38. The coil supporting mem head between said pole pieces and spaced there-. ber I6 comprises a conical lower portion and a 10 from, said core having a recess therein opening cylindrical upper portion arranged between the outwardly between said pole pieces, a stylus arm pole pieces 29 and 30, the coil l5 being mounted having a stylus at one end thereof and being on this upper portion'concentrically with the pin resiliently supported at its other end in the recess 34 and the core 3|. The magnets 25 and 26 are in said core, said stylus arm extending outwardly arranged to produce flux in the same direction from said head for holding said stylus in a posi between the pole pieces and when the stylus 6 is tion for engagement with a record sound track, displaced laterally, as viewed in Fig. 5, the coil ' and means including a coil spaced from and sur l5 rotates about an axis at right angles to the rounding said core between said pole pieces and flux path between the pole pieces and passing through the upper portion of the pin 34. This 20 supported solely by said stylus arm for trans lating into electrical variations the vibrations of motion generates a voltage in the coil which is said stylus. proportional at any instant to the velocity of the 3. An electric pickup or the like comprising a movement of the stylus. Any displacement of supporting head, a permanent magnet structure the stylus at right angles to the lateral displace ment will produce no voltage in the coil since both 25 mounted on said head and providing two spaced pole pieces, a magnetic core supported on said sides of the coil will be moved in the same di head between said pole pieces and equally spaced rection through the ñeld between the pole> pieces. The structure of the pickup is suiñciently rigid to prevent any resonant vibrations at audible fre quencies and since the moving mass associatedv 30 with the coil l5 is extremely small the stylus 6 can follow accurately the variations of the sound track of a record. During the operation of the phonograph a rec ord 1 is placed on the turntable I which is ro therefrom, said core having a central recess therein opening outwardly between said pole pieces, a stylus arm having a stylus at one end thereof, a block of resilient material arranged in said recess for supporting said stylus arm and for holding said stylus in a position for engage 35 ment with a record sound track, and means in cluding a coil spaced from and surrounding said core between said pole pieces and supported solely the stylus 6 in engagement with the sound groove by said stylus arm for translating into electrical of the record. The stylus is vibrated laterally variations the vibrations of said stylus. in accordance with the sound track and the coil 4. An electric pickup or the like comprising a l5 oscillates about its above mentioned axis 40 supporting head, a permanent magnet structure through the upper portion of the pin 34 and pro mounted on said head and providing two spaced duces voltage variations corresponding to the vi pole pieces, a magnetic core supported on said brations of the stylus. These voltage variations head between said pole pieces and equally spaced tated while the pickup 5 is placed in position with are amplified in the usual manner by suitable ll5 therefrom, said core having a recess therein apparatus connected to the leads 9. opening outwardly between said pole pieces, and From the foregoing it is readily apparent that a stylus arm having a stylus at one end thereof I have provided a phonograph pickup of simple and being resiliently supported at its other end and rugged construction which may be made in the recess in said core, said stylus arm ex with a very small moving mass so that the stylus tending Youtwardly from said head for holding may acurately follow a record sound track over said stylus in position for engagement with a a wide range of audible frequencies. While I have illustrated my invention in con nection with a particular form of phonograph pickup, other applications will readily be ap parent to those skilled in the art. I do not, there fore, desire my invention to be limited t0 the par ticular arrangement illustrated and described, and I intend by the appended claims to cover all modifications which fall within the spirit and scope of my invention. y record sound track, a hollow member secured to said stylus arm outwardly of said core and hav ing a portion between said core and said pole 55 pieces and concentric with respect to said core, and means including a coil on said concentric portion of said member for translating into elec trical variations the vibrations of said stylus. 5. An electric pickup or the like comprising a 60 What I claim as new and desire to secure by Letters Patent of the United States is: 1. An electric pickup or the like comprising a supporting head, a permanent magnet structure ` ~ supporting head, a U-shaped permanent magnet structure mounted on said head and providing two spaced pole pieces, a body of nonmagnetic material supported within said structure, a mag netic core supported on said body of materialand mounted on said head and providing two spaced 65 having a portion ’extending between said. pole pieces and equally spaced therefrom, said lcore pole pieces, a magnetic core supported on said having a recess Vtherein opening' outwardly be head between said pole pieces and spaced there tween said pole pieces, a stylus rarm having a from, a stylus arm having a stylus at one end stylus at one end thereof and being resiliently thereof, means including a block of resilient ma terial for supporting the other end of said stylus 70 supported at its other end in therecess in said core, said stylus arm extending outwardly from arm on said core with said arm extending out said head for holding said stylus in a position for wardly for holding said stylus in a position for engagement with aV record sound track, and means engagement with a record sound track, said including a coil surrounding said core between said pole pieces and supported solely by _said 75 connection between said stylus and said core, block of resilient material constituting the sole ~ 5 2,406,597 6 stylus arm for translating into electrical vari said pole pieces and opening outwardly, a stylus ations the vibrations of said stylus. arm having a stylus at one end thereof and hav 6. An electric pickup or the like comprising a ing its other end resiliently supported in there supporting head, a magnetic structure compris cess in said core, said stylus arm extending out ing two bar magnets having a. connecting yokel 5 wardly from said head for holding saidy stylus at one end and separate spaced pole pieces at the in a position for engagement with a record sound other end, a body of nonmagnetic material rigid track, and means including a coil surrounding ly supported between said bar magnets, a core said core between said pole pieces and supported of magnetic material (supported on said body of solely by said stylus arm for translating into elec material and having a portion arranged between said pole pieces and equally spaced therefrom, said core having a central recess therein between 10 trical variations the vibrations of said‘stylus. HAROLD FAUS.