US1992727A - Electric phonograph reproducer - Google Patents

Electric phonograph reproducer Download PDF

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US1992727A
US1992727A US304642A US30464228A US1992727A US 1992727 A US1992727 A US 1992727A US 304642 A US304642 A US 304642A US 30464228 A US30464228 A US 30464228A US 1992727 A US1992727 A US 1992727A
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stylus
vertical
cut
arm
playing
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US304642A
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Adolph A Thomas
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AT&T Corp
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American Telephone and Telegraph Co Inc
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00Electrostatic transducers
    • H04R19/06Gramophone pick-ups using a stylus; Recorders using a stylus
    • H04R19/08Gramophone pick-ups using a stylus; Recorders using a stylus comprising two or more styli or transducers

Definitions

  • This invention is for an electric phonograph reproducer capable of selectively playing lateralcut and vertical records without adjustment of the device on its supporting arm.
  • my double-acting pickup comprises a pair of electric elements arranged in variable inductive relation and adapted to be connected in circuit.
  • a stylus member playing lateral-cut records operates one of the electric elements, and a second stylus member playing vertical-cut records 0perates the other element.
  • the vibratory movements of either element. produce corresponding variations in their inductive relation, whereby electric impulses are generated. These impulses are suitably amplified and translated into sound.
  • the electric elements vibrated by the stylus members may be condenser plates or coils.
  • FIG. 1 shows a vertical section through a double pickup embodying my invention, in which each stylus member carries a condenser plate;
  • Fig. 2 is a plan of Fig. 1, without the housing;
  • Fig. 3 represents a modified construction, mainly in section, in which a pair of condenser plates are mounted on pivoted supports connected each to a stylus member; I 1
  • Fig. 4 is a plan of Fig. 3 Without the housing
  • Fig. 5 is a transverse section on line 5-5 of Fig. 4; a
  • Figs. 5a and 5b are sectional views of a needle arm and holder cast or molded as a single member, Fig. 5b being a section on line 5b5b of Fig. 5a;
  • Fig. 6 shows a verticalsection through a con,- struction in which each condenser element consists of a plurality of plates
  • Fig. '7 is a plan of Fig. 6 with the housing removed;
  • Fig. 8 represents a modification using a pair of coils mounted in inductive relation and each adapted to be vibrated by a stylus member;
  • Fig. 9 is a plan of Fig. 8 with the housing removed;
  • Fig. 10 is a side view of Fig. 9;
  • Fig. 11 is a fragmentary detail in section showing one of the coil-supporting members used in Figs. 810;
  • Fig. 12 shows a plan view (partly in section) of a modified form of elastic mounting for the vibratory supporting arm of one or both stylus members;
  • Fig. 13 is a transverse section on line 13-13 of Fig. 12;
  • Fig. 14 represents a sectional view on line 14-14 of Fig. 12;
  • Fig. 15 is similar to Fig. 14, showing inserted plates to regulate the normal compression of the elastic bearing in which the vibratory supporting arm is'mounted.
  • a base 10 which is shown as a disk forming the bottom of a cylindrical housing 12.
  • the housing 12 may have a lateral hub or tubular extension 14 for receiving the free end of a supporting arm which is supposed to be pivotally mounted on the top board of the phonograph in any practical way.
  • the base 10 and housing 12 may each consist of a single piece of metal or composition material, such as brass, aluminum, duralumin, Bakelite, and others along the same line, and those two parts may be cast, molded, or stamped out of sheet material.
  • the base plate 10 may be of metal and the housing 12 of Bakelite or other moldable composition material suitably colored to harmonize with the outer finish of the phonograph. What has been said above about the base 10 and housing 12 of Fig. 1 applies to the same or similar parts in Figs. 3, 6 and 8 without the need of repetition. In Figs. 1 and 3, the housing 12 has a flat top and in Figs. 6 and 8 a domed top. Either form may be spun of sheet metal.
  • the base 10 carries a pair metal and its lower end carries a stylus holder 19 adapted to support needles 20 for playing lateral-cut records.
  • the needle holder 19 maybe a cylindrical casting of brass or aluminum having a slot for receiving the lower end 18' of arm 18.
  • a rivet 21 or the like holds the parts 18 and 19 rigidly together like a single member.
  • a thumb-screw 22' operating in a lateral hole 22 of needle holder 19 clamps the inserted needle in position.
  • the line 23 in all figures represents diagrammatically the playing surface of a lateral-cut disk record engaged by the needle 20.
  • the cylindrical needle holder 19 may be cast or molded integral with the needle arm, as shown in Figs.
  • the material used may be aluminum, duralumin, brass, iron, Bakelite, and so on.
  • the arm 18 may be flat or round. To avoid useless repetition later on, let me say right here that the integral construction of needle arm and holder is applicable to all the various forms illustrated in the other views.
  • the spring blade 16 is twistable at the center to permit lateral vibration of the supported needle arm 18.
  • the member 16 acts like a resilient pivot about whiohthe needle arm vibrates, and which automatically restores the arm to normal position.
  • the right-angled needle arm 18 has a horizontal extension 18a, which carries at its free end a condenser plate 25 of brass, aluminum, or other conducting metal suitable for the purpose.
  • the condenser plate 25 is here shown as a disk, although it may have any other practical shape.
  • the insulating piece 26 consists of a disk provided with a cylindrical lug or extension 28 having a slot 29 for receiving the free end of the right-angled. needle arm 18.
  • I A suitable fastening member 30 secures the insulating piece 26 rigidly to the needle arm.
  • the lug or extension 28 may have a lateral opening 31 to receive a conductor 32 for connecting the condenser plate 25 in circuit.
  • the conducting screw 27 which connects the condenser plate 25 to the insulating support 26 clamps the inserted end of conductor 3,2 in position and thereby connects the latter electrically to the condenser plate.
  • the base 10 has a lug 33 on which one end of a, spring blade 34 is mounted as by means of a screw 35, or otherwise. If the base 10 is cast or molded, the lug 33 may be formed integral therewith otherwise, it will be attached to the base as a separate piece.
  • the spring blade 34 carries a stylus holder 36 having a stylus 37 for playing vertical-cut records.
  • the line 38 in all figures is supposed to indicate diagrammatically the playing surface of a vertical-out disk record.
  • Edison records are usually played with a diamond point permanently embedded in the holdenbut Pathe records are played with a stylus having a rounded tip of hard stone or mineral, usually sapphire.
  • the Pathe type of stylus is insertable into and removable from a holder in the same way as a needle for lateral-cut records.
  • the stylus point 37 is therefore to be regarded as representing diagrammatically any suitable member (whether permanently attached to holder 36 or removable therefrom) for playing vertical-cut records of any kind.
  • the stylus member 86 is connected to the supporting spring blade 34 in any practical way.
  • the spring blade 34 is clamped between the block 39 and the top of stylus member 36.
  • the part 39 which may be molded of Bakelite or similar material, terminates in (or is attached to) a disk 42 to which a condenser plate 43 is secured by a screw 44.
  • the condenser plate 43 is substantially identical with the upper condenser plate 25, and thetwo are arranged in vertical alignment, being normally separated by an air space 45.
  • a circuit lead '46 is connected to condenser plate 43 by being'inserted in a lateral hole 47 in block 39, and the screw 44 may conveniently be used to hold the conductor firmly clamped in electrical contact with the condenser plate.
  • the supporting spring 34 is mounted fiatwise so as to vibrate in a vertical plane when the stylus member 36 is playing a vertical-cut record.
  • spring 34 The dimensions of spring 34 are so chosen as to give it the right amount of elasticity and resistance.
  • the stylus holder 36 projects through a hole 48 inbase 10 for free vertical movement.
  • hole 48 may be lined with an elastic ring, like the hole 24, and all that previously was said about damping ring 24 is applicable to a damping ring for stylus member 36.
  • the condenser plates 25 and 43 are connected with the detector tube of any suitable amplifying circuit used in radio receivers, with which all radio fans are familiar.” It will therefore notbe necessary to show or describe any particular cir-' cuit connections for the condenser 25-43, and I need only say that variations in the capacity of the condenser affect the grid and plate circuitsof the amplif'yingsystem in the same way as radio signals, these variations being translated into sound through suitable loudspeaker mechanism.
  • the pickup above described is usedfor playing lateral-cut records, thelateral vibrations of the needlearm 18 produced by the stylus 20 move the condenser plate 25 toward and from the condenser plate 43, which is now stationary.
  • the damping ring 24' prevents vibration of the needle arm 18 and condenser plate 25 during the playing of vertical-cut records. Attention iscalled to the fact that, when the stylus point 37 is in playing position on a vertical-cut record, the lower edge 49 of the needle holder 19 is above the surface of the record, and is therefore out of the way. On the other hand, when the needle 20 is on a lateral-cutrecord, the stylus point 37 is above the plane of the record and does not interfere with the operation of the pickup. It is assumed that, before playing vertical-cut records, the needle 20 will be removed from the holder 19.
  • damping pad 50 which may simply be a small block or pad of rubber carrying a screw-threaded extension 51 mounted in base 10.
  • the spring 34 is so mounted that normally its free end is in pressure contact with the top of damping pad 50. Consequently, when the right angled needle arm 13 is vibrated by a lateral-cut record, the spring 34 and stylus member 36 are positively prevented from vibrating.
  • the weight of the pickup causes the spring 34 to bend upward sufficiently to leave its free end clear of the damping pad 56, and this separation is enough to take care of the maximum vibrations of the stylus member 36.
  • the damping pad 50 does not interfere with the free vertical movements of the spring 34 during the playing of a vertical-cut record.
  • the pad 50 is not necessary.
  • base 10 carries a pair of spaced brackets 52, which may be formed integral with the base or attached thereto as separate pieces.
  • the brackets 52 are provided with a pair of aligned vertical slots 53 and a pair of aligned horizontal slots 54. These two pairs of slots support, respectively, a vertical spring blade 55 and a horizontal spring blade 56. The ends of these spring blades fit tight in the slots and are securedby set-screws 57 and 58, or in any other practical way.
  • needle arm 59 is rigidly connected to the center of spring blade 55, which is laterally twistable to permit lateral vibration of the arm 59, as fully explained inconnection with spring blade 16 and needle arm 18 of Fig. l.
  • the lower end of needle arm 59 carries the needle holder 19, which may be considered identical with the needle holder 19 of Figs. 1 and 5a.
  • the inner end of needle arm 59 is connected at 61 to a right-angled lever or bellcrank 62, which is pivoted at its apex by means of a cross-pin 63 mounted at its ends in the brackets 52. Pointed screws 64 in brackets 52 engage correspondingly shaped recesses in the ends of pin 63 to support the latter for pivotal movement with substantially no lost motion.
  • the bellcrank 62 maybe made of metal or an insulating composition like .Bakelite.
  • a condenser plate 65 is mounted on the free end of bellcrank 63 in any practical way.
  • the condenser plate 65 has an extension 66 inserted in a slot 67 in bellcrank 62 and secured by a screw or rivet 68, which may also serve as a binding post for a circuit conductor 69.
  • the needle arm 59 and condenser plate 65 are prevented from vibrating during the playing of vertical-cut records by the vertical mounting of spring blade 55, but the opening 24 of base 10 may be lined with an elastic damping ring like ring 24, as fully explained in connection with Fig. 1.
  • the horizontal spring blade 56 carries a block or frame '70, preferably of strong insulating material having a rigid arm or extension '71 which supports the stylus member 36 for playing vertical-cut records.
  • the extension '71 has a projection '73 arranged to enter the top of stylus member 36 either in screw-threaded engagement or in a tight joint secured by a cross-pin '74.
  • the frame '70 carries a condenser plate '75 similar to the upper condenser plate 65 and secured to the frame in the same way in which the condenser plate 65 is attached to the bell crank 62.
  • the fastening member '76 for condenser plate '75 may also be used as a binding post for a conductor to connect the condenser plate in circuit. methods may be used to normally hold the bracket '70 and the parts carried thereby against vibration, so that the condenser plate '75 will remain stationary during the playing of lateral-cut records.
  • the opening 48 may be lined with an elastic ringin pressure contact with stylus member 36.
  • the damping pad 50 of Fig. 1 may also beused in Fig.
  • Another method for damping the vibrations of this unit is to mount an elastic block '77 on base 10 in permanent pressure contact with the bottom of frame '70 below the supporting spring 56.
  • the block '77 may have a screw extension '77 secured to base 10, whereby the block is adjustably mounted on the base.
  • FIG. 6 and '7 differs from that of Figs. 1 and 2 in utilizing a condenser in which each element consists of a plurality of plates.
  • a needle arm '78 which may be of metal or of strong insulating material, such as bakelite, is secured to the center of the twistable spring blade, and the inner end of this arm carries a condenser. element consisting of a plurality of Various circuit.
  • U-shaped plates '79 connected'by metallic fastening members 80.
  • One of these metallic members may actas a binding post for a conductor 81. If the needle arm 78 is of metal, the condenser plates 79 will'have to be suitably insulated from the arm.
  • the vertically movable spring blade 34 which supports the stylus member 36 carries a vertical arm 82 eitherof metal or insulating material A pair. or U-shaped condenser plates 83 are connected to-the upper end of arm 82 by metallic fastening members 84, to one of which the other circuit'lead 85 is connected. As best shown in Fig. 7, the condenser plates 79 and 83 are interleaved to form a condenser of considerable overlapping area and capacity.
  • Fig. 1 may be regarded as applicable to the construction of Fig. 6, and this includes all previous remarks concerning the damping of stylus members 19 and 36 and all parts connected thereto.
  • the base 10 carries a pair of spaced brackets 86, which may be cast integral with the base or attached thereto as separate pieces the brackets 86 have two pairs of aligned vertical slots 87 and 68 for receiving the ends of the two spring blades 39 and 90, respectively.
  • Set screws 91 or other means hold the ends of the spring blades rigidly clamped to the supporting brackets 86.
  • An arm or lever 92 is secured to the central portion of spring blade 89, which is laterally twistable to permit vibration of the arm.
  • the lower end of'arm 92 carries the usual needle holder 19.
  • the upper end of the arm supports a cylindrical shell or frame on which a coil 94 is wound.
  • the needle arm 92 is stamped from sheet metal, its upper end is twisted to provide a flat extension 92, which is easily secured to the shell 93 by a rivet or otherwise.
  • the shell 93 is preferably of thin lightmaterial, such as spun aluminum, paper, celluloid and the like As seen in' Fig. 11, a portion of the shell is formed with a recess 95 to hold the coil firmly in place. Any other practical means may be employed to mount thecoil 94 on the needle arm 92.
  • the spring blade 90 carries a bellcrank 96, which consists of a horizontal arm 9'7 and a vertical arm 98.
  • the bellcrank 96 which may be stamped as a single member from sheet metal, is secured substantially at its apex to the center of the supporting spring blade 90.
  • the horizontal arm 9"! of bellcrank 96 terminates in a vertical extension 99, to which the stylus member 36 is attached. If the extension 99 is flat, as
  • member 36 is to provide the latter with a slot for receiving the lower end of the extension, and a bolt or rivet 100 secures the parts rigidly together.
  • the inner end of the vertical arm 98 terminates in a lateral offset 101 for attaching a second shell 93 which carries a coil 102.
  • the stylus members 19 and 36, and all parts connected thereto, are damped by elastic rings 24', previously explained in detaiL'or any other practical way.
  • spring blade '90 which may also be mounted horizontally, is so dimensioned as to twist or pivot about its axis under the vertical movements of. stylus member 36. Since the horizontal arm 97 is shorter than the vertical arm 98 of bellcrank 96, the movements of stylus member 36 are transmitted to the inner end of arm 98 in amplified ratio.
  • the coils 94 and 102 are arranged as closely together as possible without actually touching, and they normally overlap a certain amount, as indicated in Figs. 8 and 9.
  • One of the coils is connected in a circuit of substantially constant current to produce a magnetic field for inducing current impulses in the other coil during the vibration of either coil.
  • the coil 94 is connected in a circuit of substantially constant current to produce a magnetic field of the required strength.
  • a certain percentage of the magnetic lines of force will pass through the coil 102 supported on the inner end of bellcrank 96.
  • the laterally twistable spring blade 90 permits vibration of the bellcrank 96, sothat the coil 102 moves transversely of the stationary coil 94 in a direction to cut the magnetic lines of force.
  • the result of this operation is the generation of current impulses in the circuit of coil, 102, and these induced impulses, which represent the recorded sound, are suitably amplified to operate loudspeaker mechanism. Since radio amplifying circuits are well known and have heretofore been used in electric phonograph reproduction, I do not think it necessary to encumber this case with a description and illustration of circuit connections. It is enough to say that the current impulses produced in coil 102 by cutting the magnetic flux of coil 94 are utilized to operate or control suitable sound-reproducing apparatus.
  • the needle arm 92 vibrates the coil 94 laterally of the stationary coil 102, so that the lines of force passing through coil 102 are correspondingly varied to induce current impulses.
  • the two coils 94-102 constitute a miniature electric generator, oneof them serving to maintain a magnetic field and the other operating as an armature. It is immaterial which is the field coil andwhich the armature coil.
  • transmission ratios between the points of the operating styli 20-37 and the coils 94102 may be so adjusted that the movements of the stylus points are communicated to the coils either in .1
  • Figs. 12-15 show another form of resilient mounting for the needle holder 19.
  • the laterally twistable spring blade of the preceding constructions is replaced by a rigid arm or shaft 103 pivoted at its ends in adjustable bearing screws 104, which are mounted in brackets 105 fixed on the base plate 10.
  • Each bracket 105 has a recess 106 containing elastic material 107, such as rubber, which surrounds the end portions of shaft 103, or at least engages the opposite sides thereof. 108, which are removably attached to the brackets by screws 109 or otherwise.
  • the elastic material 107 in recesses 106 is held under predetermined normal compression, so as to resist rotary movement of shaft 103 which carries the needle holder
  • the recesses 106 are closed by plates 19.
  • the latter is attached to an arm 110, which represents any of the needle arms heretofore described or any other practical form of v stylus arm.
  • the fiat or angular shaft 103 may pass through a correspondingly shaped slot in arm 110, which is held against lateral movementon the shaft by pins 112 or otherwise.
  • I may insert thin plates 113 of certain thickness in the recesses 106 (see Fig. 15) to regulate the normal pressure of the elastic material'lO'? against the shaft 103. It is understood that this damped elastic mounting may be substituted in any of the preceding figures for the elastic spring blades supported at their ends.
  • the compressed elastic material 107 constitutes a combined spring support anddamping means for shaft 103.
  • the stylus members 19 and 36 engage the records at the usual trailing angle.
  • the simplest way to obtain this arrangement is to support the entire casing at the proper angle, as will be understood without additional illustration. If the casing is mounted in a vertical position, the stylus holders 19 and 36 are arranged at the correct slant.
  • An electric phonograph reproducer comprising a pair of inductively related elements adapted to be connected in circuit, means operated by a lateral-cut record for vibrating one of said elements, and means operated by a verticalcut record for vibrating the other element.
  • An electric phonograph reproducer comprising apair of movable condenser elements adapted to be connected in circuit, means operated by a lateral-cut record for vibrating one of said elements, and means operated by a vertical-cut record for vibrating the other element.
  • An electric phonograph reproducer comprising a pair of independently operable stylus members for playing lateral-cut and'vertical-cut records respectively, and a pair of condenser elements carried bysaid members.
  • An electric phonograph reproducer comprising a pair of electric elements arranged in variable inductive relationand adapted to be connected in circuit, a stylus member operated by a lateral-cut record for vibrating one of said coils, a second stylus member operated by a vertical-cut record for vibrating the other coil, and resilient means for holding said stylus members in normal predetermined position.
  • An electric phonograph reproducer adapted to be mounted as a unit on a supporting arm for selectively playing lateral-cut and vertical-cut records, said unit comprising a variable condenser adapted to be connected in circuit, and means carried by said unit for varying the capacity for said condenser in accordance with variations in the stylus grooves of lateral-cut records and vertical-cut records.
  • a support provided with a pair of recesses, a pair ofaligned bearings carried by said support, a shaft pivoted at its ends in said bearings and extending into said recesses, elastic material held under compression in said recesses and engaging said shaft in pressure contact to permit rotary movement thereof in either dii'ection'and at the same time damp said movement, said elastic material being separate from said bearings and operating independently thereof, and a vibratory member connected to said shaft.
  • an electric pronograph reproducer for selectively playing lateral-cut and vertical-cut records, the combination of a pair of electric elements arranged in inductive relation and adapted to be connected in circuit, a stylus member for vibrating one of said elements in playing lateral-cut records, and a secondstylus member for vibrating the other element in playing'vertical-cut records.
  • an electric phonograph reproducer for selectively playing lateral-cut and vertical-cut records, the combination of a pair of independently operable stylus members for playing lateral-cut and vertical-cut records respectively, and a pair of electric elements carried by said members, said elements being arranged in inductive 12.
  • An electric phonograph reproducer adapted to be mounted as a unit on a supporting arm for selectively playing lateral-cut and vertical-cut records, said unit comprising a pair of inductively related coils adapted to be connected in circuit, and means carried by said unit for varying the inductive relation of said coils in accordance with variations in the stylus grooves of lateral-cut records and vertical-cut records.
  • an electric phonograph reproducer for playing lateral-cut and vertical-cut records, the combination of a pair of electric elements arranged in inductive relation and adapted to be connected in circuit, a pivoted needle arm for playing lateral-cut records connected to one of said elements, a vertically movable stylus holder for playing vertical-cut records connected to the other element, and resilient means for holding said needle arm and stylus holder in predetermined normal position.
  • An electric phonograph reproducer comprising a shaft with flat pointed ends, a support carrying a pair of bearing screws for receiving said pointed ends and thereby supporting the shaft for rotary movement, elastic packing mounted in said support and surrounding the fiat ends of said shaft to damp the vibrations thereof, means on said support for holding said packing compressed, and electric reproducing means having a vibratory member connected to said shaft.
  • an electric phonograph reproducer for playing lateral-cut and vertical-cut records, the combination of a pair of electric elements arranged in inductive relation and adapted to be connected in circuit, a stylus member for vibrating one of said elements in playing lateral-cut records, a second stylus member for vibrating the other element in playing vertical-cut records, a mounting for each of said stylus members, and elastic damping means for said stylus members.
  • an electric phonograph reproducer for selectively playing lateral-cut and vertical-cut records, the combination of a pair of electric elements arranged in inductive relation and adapted to be connected in circuit, a stylus member for vibrating one of said elements in playing lateralout records, a second stylus member for vibrating the other element in playing vertical-cut records, and a resilient mounting for each of said stylus members, said mountings being also adapted to hold said elements in predetermined normal position.
  • an electric phonograph reproducer for selectively playing lateral-cut and vertical-cut records, the combination of a pair of electric ele--- ments arranged in inductive relation and adapted to be connected in circuit, a pivoted needle arm for playing lateral-cut records connected to one of said elements, a vertically movable stylus holder for playing vertical-cut records connected to the other element, and a pair of twistable spring blades on which said needle arm and stylus holder are mounted for independent operation, said spring blades also holding said elements in predetermined normal position.
  • An electric phonograph reproducer comprising a casing adapted to be operatively mounted ona supporting arm, a pair of stylus members carried by casing and projecting through open-v ings in the bottom thereof, so that either member may be placed in playing contact with a record, one of said members being adapted to play lateral-cut records and the other member being operable on vertical-cut records without adjusting the position of the casing on its supporting arm, a pair of electric elements in said casing, said elements being arranged in variable inductive relation and adapted to be connected in circuit, and means whereby the operation of one stylus member vibrates one-of said elements and the operation of the other member vibrates the other element.
  • a casing provided with an opening at the bottom, a stylus member mounted in said casing for vertical movement by a vertical-cut record opening, resilient means surrounding said member for closing said opening and damping the vibrations of said member, and means for converting the movements of said member into electric impulses.
  • An electric phonograph device comprising the combination of a horizontally pivoted shaft, a stylus holder connected to said shaft and adapted to vibrate laterally,.a stationary element, a second element connected to said shaft to vibrate therewith, said elements being operatively associated to produce electric impulses when the second element vibrates, and elastic damping means surrounding said shaft;
  • a casing provided with an opening at the bottom, an element supported horizontally in said casing for vibratory movement in a vertical direction, astylus member secured to said element for vertical movement by a vertical-cut record groove, said stylus member extending through said opening, resilient material surrounding said stylus member for closing said opening and damping the vibrations of said member, and means for converting the movements of said element into electric impulses.
  • a phonograph reproducer for vertical cut records a casing provided Withan opening at the bottom, a flat resilient element supported horizontally in said casing for vibratory movement in a vertical direction, one end of. said element being secured and the other end being free to vibrate, a stylus member connected to the free end of said element and supported thereby for vertical movement by a vertical-cut record groove, said stylus member extending through said opening substantially at right angles to said element, resilient material surrounding said stylus member for closing said opening and damping the vibrations of said member, and means for converting the movements of said element into electric impulses.

Description

Feb. 26, 1935. A. A. THOMAS ELECTRIC PHONOGRAPH REPRODUCER Original Filed Sept. 8, 1928 3 Sheets-Sheet 1 INVENTOR 3 Sheets-Sheet 3 INVENTOR Feb. 26,1935. A. A. THOMAS ELECTRIC PHONOGRAPH REPRODUCER Original Filed Sept. 8, 1928 P ELI Patented Feb. 26, 1935 PATENT OFFICE 1,992,727 ELECTRIC PHONOGRAPH REPRODUCER Adolph A. Thomas, New York, N. Y., assignor to American Telephone and Telegraph Company,
a corporation of New York Application September 8, 1928, Serial No. 304,642
Renewed April 17, 1934 22 Claims.
This invention is for an electric phonograph reproducer capable of selectively playing lateralcut and vertical records without adjustment of the device on its supporting arm. Briefly stated, my double-acting pickup comprises a pair of electric elements arranged in variable inductive relation and adapted to be connected in circuit. A stylus member playing lateral-cut records operates one of the electric elements, and a second stylus member playing vertical-cut records 0perates the other element. The vibratory movements of either element. produce corresponding variations in their inductive relation, whereby electric impulses are generated. These impulses are suitably amplified and translated into sound. The electric elements vibrated by the stylus members may be condenser plates or coils.
The novel features and practical advantages of my invention will be fully understood from a detailed description of the accompanying drawings, in which- Fig. 1 shows a vertical section through a double pickup embodying my invention, in which each stylus member carries a condenser plate;
Fig. 2 is a plan of Fig. 1, without the housing;
Fig. 3 represents a modified construction, mainly in section, in which a pair of condenser plates are mounted on pivoted supports connected each to a stylus member; I 1
Fig. 4 is a plan of Fig. 3 Without the housing;
Fig. 5 is a transverse section on line 5-5 of Fig. 4; a
Figs. 5a and 5b are sectional views of a needle arm and holder cast or molded as a single member, Fig. 5b being a section on line 5b5b of Fig. 5a;
Fig. 6 shows a verticalsection through a con,- struction in which each condenser element consists of a plurality of plates;
Fig. '7 is a plan of Fig. 6 with the housing removed;
Fig. 8 represents a modification using a pair of coils mounted in inductive relation and each adapted to be vibrated by a stylus member;
Fig. 9 is a plan of Fig. 8 with the housing removed;
Fig. 10 is a side view of Fig. 9;
Fig. 11 is a fragmentary detail in section showing one of the coil-supporting members used in Figs. 810;
Fig. 12 shows a plan view (partly in section) of a modified form of elastic mounting for the vibratory supporting arm of one or both stylus members;
Fig. 13 is a transverse section on line 13-13 of Fig. 12;
r Fig. 14 represents a sectional view on line 14-14 of Fig. 12; and
Fig. 15 is similar to Fig. 14, showing inserted plates to regulate the normal compression of the elastic bearing in which the vibratory supporting arm is'mounted.
Before taking up a detailed description of the drawings, I might as well'explain that the various parts have been exaggerated in size and spread apart for clearness. No attempt has been made to show the different constructions in approved commercial designs, and it Will therefore be unf derstood that the drawings are merely for illustrative purposes and not made to mathematical scale. The mechanic can look after shop drawings to suit the manufacturer.- I
Referring to Figs. 1 and 2, the operative parts of the instrument are mounted on a base 10, which is shown as a disk forming the bottom of a cylindrical housing 12. Suitable fastening members, such as screws 13, connect these parts together to form a closed casing to be mounted on a suitable supporting arm. The housing 12 may have a lateral hub or tubular extension 14 for receiving the free end of a supporting arm which is supposed to be pivotally mounted on the top board of the phonograph in any practical way. The base 10 and housing 12 may each consist of a single piece of metal or composition material, such as brass, aluminum, duralumin, Bakelite, and others along the same line, and those two parts may be cast, molded, or stamped out of sheet material. The base plate 10 may be of metal and the housing 12 of Bakelite or other moldable composition material suitably colored to harmonize with the outer finish of the phonograph. What has been said above about the base 10 and housing 12 of Fig. 1 applies to the same or similar parts in Figs. 3, 6 and 8 without the need of repetition. In Figs. 1 and 3, the housing 12 has a flat top and in Figs. 6 and 8 a domed top. Either form may be spun of sheet metal.
In Figs. 1 and 2, the base 10 carries a pair metal and its lower end carries a stylus holder 19 adapted to support needles 20 for playing lateral-cut records. The needle holder 19 maybe a cylindrical casting of brass or aluminum having a slot for receiving the lower end 18' of arm 18. A rivet 21 or the like holds the parts 18 and 19 rigidly together like a single member. A thumb-screw 22' operating in a lateral hole 22 of needle holder 19 (see Figs. a and 5b) clamps the inserted needle in position. The line 23 in all figures represents diagrammatically the playing surface of a lateral-cut disk record engaged by the needle 20. The cylindrical needle holder 19 may be cast or molded integral with the needle arm, as shown in Figs. 5a and 5b, and for this purpose the material used may be aluminum, duralumin, brass, iron, Bakelite, and so on. The arm 18 may be flat or round. To avoid useless repetition later on, let me say right here that the integral construction of needle arm and holder is applicable to all the various forms illustrated in the other views.
The spring blade 16 is twistable at the center to permit lateral vibration of the supported needle arm 18. In other words, the member 16 acts like a resilient pivot about whiohthe needle arm vibrates, and which automatically restores the arm to normal position. The dimensions of the spring blade 16 are so chosen as to have the: proper amount of elasticity and torsional resistance. It will be observed that the plane of the spring blade 16 is approximately at right angles to the plane of the disk record 23. "This means that spring 16 is in a position of maximum strength to support the weight of the reproducer during the playing of a record. =Thebase has an opening 24 through which the needle holder 19 extends, and this opening may be lined with a rubber ring 24 which always presses radially against the cylindrical needle holder all the way round to damp the vibrations thereof. The elasticity of the damping ring 24, which may be fastened either to the needle holder or to the Walls of opening 24, readily allows vibration of the needle arm at all amplitudes in accordance with the record groove, and yet it stops (or at least reduces to a minimum) the tendency of the unit to vibrate by virtue of itsinertia or inherent resonance. In some cases the damping ring 24 may be omitted.
' In Figs. 1 and 2, the right-angled needle arm 18 has a horizontal extension 18a, which carries at its free end a condenser plate 25 of brass, aluminum, or other conducting metal suitable for the purpose. The condenser plate 25 is here shown as a disk, although it may have any other practical shape. To insulate the disk 25 if the arrn18 is of metal, it is attached to an insulating piece 26 of fBakelite or other insulating material by means of a screw 27. The insulating piece 26 consists of a disk provided with a cylindrical lug or extension 28 having a slot 29 for receiving the free end of the right-angled. needle arm 18. I A suitable fastening member 30 secures the insulating piece 26 rigidly to the needle arm. The lug or extension 28 may have a lateral opening 31 to receive a conductor 32 for connecting the condenser plate 25 in circuit. The conducting screw 27 which connects the condenser plate 25 to the insulating support 26 clamps the inserted end of conductor 3,2 in position and thereby connects the latter electrically to the condenser plate.
The base 10 has a lug 33 on which one end of a, spring blade 34 is mounted as by means of a screw 35, or otherwise. If the base 10 is cast or molded, the lug 33 may be formed integral therewith otherwise, it will be attached to the base as a separate piece. The spring blade 34 carries a stylus holder 36 having a stylus 37 for playing vertical-cut records. The line 38 in all figures is supposed to indicate diagrammatically the playing surface of a vertical-out disk record. Edison records are usually played with a diamond point permanently embedded in the holdenbut Pathe records are played with a stylus having a rounded tip of hard stone or mineral, usually sapphire. The Pathe type of stylus is insertable into and removable from a holder in the same way as a needle for lateral-cut records. The stylus point 37 is therefore to be regarded as representing diagrammatically any suitable member (whether permanently attached to holder 36 or removable therefrom) for playing vertical-cut records of any kind. The stylus member 86 is connected to the supporting spring blade 34 in any practical way. In the present instance, there is a block or pin 39 of insulating materal having an extension 40 projecting into a hole in the top of stylus member 36 and secured by a screw or rivet 41; or, the extension 40 may be a screw in screwthreaded' engagement with the stylus member. In either case, the spring blade 34 is clamped between the block 39 and the top of stylus member 36. The part 39, which may be molded of Bakelite or similar material, terminates in (or is attached to) a disk 42 to which a condenser plate 43 is secured by a screw 44. The condenser plate 43 is substantially identical with the upper condenser plate 25, and thetwo are arranged in vertical alignment, being normally separated by an air space 45. A circuit lead '46 is connected to condenser plate 43 by being'inserted in a lateral hole 47 in block 39, and the screw 44 may conveniently be used to hold the conductor firmly clamped in electrical contact with the condenser plate. The supporting spring 34 is mounted fiatwise so as to vibrate in a vertical plane when the stylus member 36 is playing a vertical-cut record. The dimensions of spring 34 are so chosen as to give it the right amount of elasticity and resistance. The stylus holder 36 projects through a hole 48 inbase 10 for free vertical movement. hole 48 may be lined with an elastic ring, like the hole 24, and all that previously was said about damping ring 24 is applicable to a damping ring for stylus member 36. v
The condenser plates 25 and 43 are connected with the detector tube of any suitable amplifying circuit used in radio receivers, with which all radio fans are familiar." It will therefore notbe necessary to show or describe any particular cir-' cuit connections for the condenser 25-43, and I need only say that variations in the capacity of the condenser affect the grid and plate circuitsof the amplif'yingsystem in the same way as radio signals, these variations being translated into sound through suitable loudspeaker mechanism. When the pickup above described is usedfor playing lateral-cut records, thelateral vibrations of the needlearm 18 produced by the stylus 20 move the condenser plate 25 toward and from the condenser plate 43, which is now stationary. The variations in the capacity thus produced are utilizedto generate current impulses for operating a loudspeaker, which reproducesthe sounds recorded in the record that is being played. For playing vertical-cut records, it is only necessary to place the stylus 3.7 in the record groove. The vertical movements of stylus member 36 movethe condenser plate 43 toward and from the stationary If desired or advisable, the
condenser plate 25, thereby producing variations in capacity which are finally translated into' sound, as above explained. The damping ring 24' prevents vibration of the needle arm 18 and condenser plate 25 during the playing of vertical-cut records. Attention iscalled to the fact that, when the stylus point 37 is in playing position on a vertical-cut record, the lower edge 49 of the needle holder 19 is above the surface of the record, and is therefore out of the way. On the other hand, when the needle 20 is on a lateral-cutrecord, the stylus point 37 is above the plane of the record and does not interfere with the operation of the pickup. It is assumed that, before playing vertical-cut records, the needle 20 will be removed from the holder 19.
In some instances, when no damping ring is used in the opening 48 for stylus member 36, it may be found desirable or advisable to have the free end of spring blade 34 normally engage a damping pad 50, which may simply be a small block or pad of rubber carrying a screw-threaded extension 51 mounted in base 10. In that case, the spring 34 is so mounted that normally its free end is in pressure contact with the top of damping pad 50. Consequently, when the right angled needle arm 13 is vibrated by a lateral-cut record, the spring 34 and stylus member 36 are positively prevented from vibrating. When the stylus point 3'7 is placed on a vertical-cut record, the weight of the pickup causes the spring 34 to bend upward sufficiently to leave its free end clear of the damping pad 56, and this separation is enough to take care of the maximum vibrations of the stylus member 36. I mean by this that the damping pad 50 does not interfere with the free vertical movements of the spring 34 during the playing of a vertical-cut record. When a damping ring is used in opening 48, the pad 50 is not necessary.
In the modification of Figs. 3, 4 and 5, the
base 10 carries a pair of spaced brackets 52, which may be formed integral with the base or attached thereto as separate pieces. The brackets 52 are provided with a pair of aligned vertical slots 53 and a pair of aligned horizontal slots 54. These two pairs of slots support, respectively, a vertical spring blade 55 and a horizontal spring blade 56. The ends of these spring blades fit tight in the slots and are securedby set- screws 57 and 58, or in any other practical way. A
needle arm 59 is rigidly connected to the center of spring blade 55, which is laterally twistable to permit lateral vibration of the arm 59, as fully explained inconnection with spring blade 16 and needle arm 18 of Fig. l. The lower end of needle arm 59 carries the needle holder 19, which may be considered identical with the needle holder 19 of Figs. 1 and 5a. The inner end of needle arm 59, is connected at 61 to a right-angled lever or bellcrank 62, which is pivoted at its apex by means of a cross-pin 63 mounted at its ends in the brackets 52. Pointed screws 64 in brackets 52 engage correspondingly shaped recesses in the ends of pin 63 to support the latter for pivotal movement with substantially no lost motion.
The bellcrank 62 maybe made of metal or an insulating composition like .Bakelite. A condenser plate 65 is mounted on the free end of bellcrank 63 in any practical way. In the example illustrated, the condenser plate 65 has an extension 66 inserted in a slot 67 in bellcrank 62 and secured by a screw or rivet 68, which may also serve as a binding post for a circuit conductor 69. The needle arm 59 and condenser plate 65 are prevented from vibrating during the playing of vertical-cut records by the vertical mounting of spring blade 55, but the opening 24 of base 10 may be lined with an elastic damping ring like ring 24, as fully explained in connection with Fig. 1.
Still referring to Figs. 3-5, the horizontal spring blade 56 carries a block or frame '70, preferably of strong insulating material having a rigid arm or extension '71 which supports the stylus member 36 for playing vertical-cut records. The extension '71 has a projection '73 arranged to enter the top of stylus member 36 either in screw-threaded engagement or in a tight joint secured by a cross-pin '74. The frame '70 carries a condenser plate '75 similar to the upper condenser plate 65 and secured to the frame in the same way in which the condenser plate 65 is attached to the bell crank 62., The fastening member '76 for condenser plate '75 may also be used as a binding post for a conductor to connect the condenser plate in circuit. methods may be used to normally hold the bracket '70 and the parts carried thereby against vibration, so that the condenser plate '75 will remain stationary during the playing of lateral-cut records. For example, the opening 48 may be lined with an elastic ringin pressure contact with stylus member 36. Or, the damping pad 50 of Fig. 1 may also beused in Fig. 3 for normally engaging the free end of extension '71, which is held against the pad by the normal set of the supporting spring 56. Another method for damping the vibrations of this unit is to mount an elastic block '77 on base 10 in permanent pressure contact with the bottom of frame '70 below the supporting spring 56. The block '77 may have a screw extension '77 secured to base 10, whereby the block is adjustably mounted on the base.
In the operation of the pickup illustrated in Figs 3-5, the lateral vibrations of needle arm 59 about the elastic pivot support 55 rock the bellcrank 62 on its pivot 63, whereby the condenser plate 65 is moved toward and from the stationary condenser plate '75. When the stylus member 36 is used to play vertical-cut records, the frame '70 is vibrated vertically about the twistable spring blade 56, so that the condenser plate '75 is moved toward and away from the stationary condenser plate 65. The variations in the capacity of the condenser due to the vibration of either condenser plate are translated into current impulses to operate suitable loudspeaker mechanism, as more fully explained in connection with Fig. 1. The connection 61 between the bellcrank 62 and needle arm 59 need not be in the form of a pivot member, but can be rigid, because the movements of the parts are very small.
The construction illustrated in Figs. 6 and '7 differs from that of Figs. 1 and 2 in utilizing a condenser in which each element consists of a plurality of plates. To avoid needles repetition of description, I have used the same reference numerals in Fig. 6 as in Fig. l to indicate similar parts. It will therefore be understood that the detailed description of Fig. l"is fully applicable to Figs. 6 and '7, so far as like parts are concerned. A needle arm '78, which may be of metal or of strong insulating material, such as bakelite, is secured to the center of the twistable spring blade, and the inner end of this arm carries a condenser. element consisting of a plurality of Various circuit.
U-shaped plates '79 connected'by metallic fastening members 80. One of these metallic members may actas a binding post for a conductor 81. If the needle arm 78 is of metal, the condenser plates 79 will'have to be suitably insulated from the arm. The vertically movable spring blade 34 which supports the stylus member 36 carries a vertical arm 82 eitherof metal or insulating material A pair. or U-shaped condenser plates 83 are connected to-the upper end of arm 82 by metallic fastening members 84, to one of which the other circuit'lead 85 is connected. As best shown in Fig. 7, the condenser plates 79 and 83 are interleaved to form a condenser of considerable overlapping area and capacity. The plates are spaced as closely together as mechanical conditions permit. The spring blades 16 and 3-2 prevent lateral movement of the condenser plates, so that there is no danger of their coming in contact with each other to produce a short If desired, the adjacent sides of the condenser plates may be covered or coated with suitable insulation. Otherwise, what has been said for the operation of Fig. 1 may be regarded as applicable to the construction of Fig. 6, and this includes all previous remarks concerning the damping of stylus members 19 and 36 and all parts connected thereto. a
In the modification'ot Figs. 8-11, I use a pair of inductively'related coils to produce current impulses when either stylus member is in opera tion. The base 10 carries a pair of spaced brackets 86, which may be cast integral with the base or attached thereto as separate pieces the brackets 86 have two pairs of aligned vertical slots 87 and 68 for receiving the ends of the two spring blades 39 and 90, respectively. Set screws 91 or other means hold the ends of the spring blades rigidly clamped to the supporting brackets 86. An arm or lever 92 is secured to the central portion of spring blade 89, which is laterally twistable to permit vibration of the arm. The lower end of'arm 92 carries the usual needle holder 19. and the upper end of the arm supports a cylindrical shell or frame on which a coil 94 is wound. If the needle arm 92 is stamped from sheet metal, its upper end is twisted to provide a flat extension 92, which is easily secured to the shell 93 by a rivet or otherwise. The shell 93 is preferably of thin lightmaterial, such as spun aluminum, paper, celluloid and the like As seen in' Fig. 11, a portion of the shell is formed with a recess 95 to hold the coil firmly in place. Any other practical means may be employed to mount thecoil 94 on the needle arm 92.
The spring blade 90 carries a bellcrank 96, which consists of a horizontal arm 9'7 and a vertical arm 98. The bellcrank 96, which may be stamped as a single member from sheet metal, is secured substantially at its apex to the center of the supporting spring blade 90. The horizontal arm 9"! of bellcrank 96 terminates in a vertical extension 99, to which the stylus member 36 is attached. If the extension 99 is flat, as
shown, an easy way to attach the stylus: member 36 is to provide the latter with a slot for receiving the lower end of the extension, and a bolt or rivet 100 secures the parts rigidly together. The inner end of the vertical arm 98 terminates in a lateral offset 101 for attaching a second shell 93 which carries a coil 102. The stylus members 19 and 36, and all parts connected thereto, are damped by elastic rings 24', previously explained in detaiL'or any other practical way. The
spring blade '90, which may also be mounted horizontally, is so dimensioned as to twist or pivot about its axis under the vertical movements of. stylus member 36. Since the horizontal arm 97 is shorter than the vertical arm 98 of bellcrank 96, the movements of stylus member 36 are transmitted to the inner end of arm 98 in amplified ratio.
The coils 94 and 102 are arranged as closely together as possible without actually touching, and they normally overlap a certain amount, as indicated in Figs. 8 and 9. One of the coils is connected in a circuit of substantially constant current to produce a magnetic field for inducing current impulses in the other coil during the vibration of either coil. Let us assume, by way of example, that the coil 94 is connected in a circuit of substantially constant current to produce a magnetic field of the required strength. A certain percentage of the magnetic lines of force will pass through the coil 102 supported on the inner end of bellcrank 96. When the stylus member 36 is vibrated vertically in playing a vertical-cut record, the laterally twistable spring blade 90 permits vibration of the bellcrank 96, sothat the coil 102 moves transversely of the stationary coil 94 in a direction to cut the magnetic lines of force. The result of this operation is the generation of current impulses in the circuit of coil, 102, and these induced impulses, which represent the recorded sound, are suitably amplified to operate loudspeaker mechanism. Since radio amplifying circuits are well known and have heretofore been used in electric phonograph reproduction, I do not think it necessary to encumber this case with a description and illustration of circuit connections. It is enough to say that the current impulses produced in coil 102 by cutting the magnetic flux of coil 94 are utilized to operate or control suitable sound-reproducing apparatus.
In playing lateral-cut records, the needle arm 92 vibrates the coil 94 laterally of the stationary coil 102, so that the lines of force passing through coil 102 are correspondingly varied to induce current impulses. It is clear from what has been said that the two coils 94-102 constitute a miniature electric generator, oneof them serving to maintain a magnetic field and the other operating as an armature. It is immaterial which is the field coil andwhich the armature coil. The
transmission ratios between the points of the operating styli 20-37 and the coils 94102 may be so adjusted that the movements of the stylus points are communicated to the coils either in .1
increased ratio, or without amplification, or in decreased ratio, depending on the particular design of the instrument and the special form of amplifying circuit which it is proposed to use.
Figs. 12-15 show another form of resilient mounting for the needle holder 19. In this case, the laterally twistable spring blade of the preceding constructions is replaced by a rigid arm or shaft 103 pivoted at its ends in adjustable bearing screws 104, which are mounted in brackets 105 fixed on the base plate 10. Each bracket 105 has a recess 106 containing elastic material 107, such as rubber, which surrounds the end portions of shaft 103, or at least engages the opposite sides thereof. 108, which are removably attached to the brackets by screws 109 or otherwise. "The elastic material 107 in recesses 106 is held under predetermined normal compression, so as to resist rotary movement of shaft 103 which carries the needle holder The recesses 106 are closed by plates 19. The latter is attached to an arm 110, which represents any of the needle arms heretofore described or any other practical form of v stylus arm. The fiat or angular shaft 103 may pass through a correspondingly shaped slot in arm 110, which is held against lateral movementon the shaft by pins 112 or otherwise. I may insert thin plates 113 of certain thickness in the recesses 106 (see Fig. 15) to regulate the normal pressure of the elastic material'lO'? against the shaft 103. It is understood that this damped elastic mounting may be substituted in any of the preceding figures for the elastic spring blades supported at their ends. The compressed elastic material 107 constitutes a combined spring support anddamping means for shaft 103.
It is hardly necessary to mentionthat the stylus members 19 and 36, in all the constructions above described, engage the records at the usual trailing angle. The simplest way to obtain this arrangement is to support the entire casing at the proper angle, as will be understood without additional illustration. If the casing is mounted in a vertical position, the stylus holders 19 and 36 are arranged at the correct slant.
Although "I have shown and described certain specific embodiments of my invention, I want it clearly understood thatmy invention is not limitedto the details set forth. Changes and modifications may be made without departing from the scope of the invention as defined in the appended claims. l
I claim as my invention:
1. An electric phonograph reproducer comprising a pair of inductively related elements adapted to be connected in circuit, means operated by a lateral-cut record for vibrating one of said elements, and means operated by a verticalcut record for vibrating the other element.
2. An electric phonograph reproducer comprising apair of movable condenser elements adapted to be connected in circuit, means operated by a lateral-cut record for vibrating one of said elements, and means operated by a vertical-cut record for vibrating the other element.
3. An electric phonograph reproducer comprising a pair of independently operable stylus members for playing lateral-cut and'vertical-cut records respectively, and a pair of condenser elements carried bysaid members.
4.. An electric phonograph reproducer comprising a pair of electric elements arranged in variable inductive relationand adapted to be connected in circuit, a stylus member operated by a lateral-cut record for vibrating one of said coils, a second stylus member operated by a vertical-cut record for vibrating the other coil, and resilient means for holding said stylus members in normal predetermined position.
5. An electric phonograph reproducer adapted to be mounted as a unit on a supporting arm for selectively playing lateral-cut and vertical-cut records, said unit comprising a variable condenser adapted to be connected in circuit, and means carried by said unit for varying the capacity for said condenser in accordance with variations in the stylus grooves of lateral-cut records and vertical-cut records.
6. In an electric phonograph reproducer, the combination of an arm and stylus holder molded as a single member of insulating material of the type represented by phenol condensation products, and means for converting the movements of said member into electric impulses.
7. In an electric reproducer, the combination of a pair of aligned bearings, a shaft pivoted at its ends in saidbearings, a vibratory member connected to the center of said shaft, elastic means separate from said bearings for engaging said shaft to permit rotary movement thereof in either direction and at the same time damp said movement, means independent of said bearings for holding said elastic means under compression, and electric reproducing means connected to said member.
8. In an electric reproducer, a support provided with a pair of recesses, a pair ofaligned bearings carried by said support, a shaft pivoted at its ends in said bearings and extending into said recesses, elastic material held under compression in said recesses and engaging said shaft in pressure contact to permit rotary movement thereof in either dii'ection'and at the same time damp said movement, said elastic material being separate from said bearings and operating independently thereof, and a vibratory member connected to said shaft. 7 V
- 9. In an electric pronograph reproducer for selectively playing lateral-cut and vertical-cut records, the combination of a pair of electric elements arranged in inductive relation and adapted to be connected in circuit, a stylus member for vibrating one of said elements in playing lateral-cut records, and a secondstylus member for vibrating the other element in playing'vertical-cut records.
10. In an electric phonograph reproducer for selectively playing lateral-cut and vertical-cut records, the combination of a pair of independently operable stylus members for playing lateral-cut and vertical-cut records respectively, and a pair of electric elements carried by said members, said elements being arranged in inductive 12. An electric phonograph reproducer adapted to be mounted as a unit on a supporting arm for selectively playing lateral-cut and vertical-cut records, said unit comprising a pair of inductively related coils adapted to be connected in circuit, and means carried by said unit for varying the inductive relation of said coils in accordance with variations in the stylus grooves of lateral-cut records and vertical-cut records.
13. In an electric phonograph reproducer for playing lateral-cut and vertical-cut records, the combination of a pair of electric elements arranged in inductive relation and adapted to be connected in circuit, a pivoted needle arm for playing lateral-cut records connected to one of said elements, a vertically movable stylus holder for playing vertical-cut records connected to the other element, and resilient means for holding said needle arm and stylus holder in predetermined normal position.
14. An electric phonograph reproducer comprising a shaft with flat pointed ends, a support carrying a pair of bearing screws for receiving said pointed ends and thereby supporting the shaft for rotary movement, elastic packing mounted in said support and surrounding the fiat ends of said shaft to damp the vibrations thereof, means on said support for holding said packing compressed, and electric reproducing means having a vibratory member connected to said shaft.
l5.-In an electric phonograph reproducer for playing lateral-cut and vertical-cut records, the combination of a pair of electric elements arranged in inductive relation and adapted to be connected in circuit, a stylus member for vibrating one of said elements in playing lateral-cut records, a second stylus member for vibrating the other element in playing vertical-cut records, a mounting for each of said stylus members, and elastic damping means for said stylus members.
16. In an electric phonograph reproducer for selectively playing lateral-cut and vertical-cut records, the combination of a pair of electric elements arranged in inductive relation and adapted to be connected in circuit, a stylus member for vibrating one of said elements in playing lateralout records, a second stylus member for vibrating the other element in playing vertical-cut records, and a resilient mounting for each of said stylus members, said mountings being also adapted to hold said elements in predetermined normal position.
1'7. In an electric phonograph reproducer for selectively playing lateral-cut and vertical-cut records, the combination of a pair of electric ele-- ments arranged in inductive relation and adapted to be connected in circuit, a pivoted needle arm for playing lateral-cut records connected to one of said elements, a vertically movable stylus holder for playing vertical-cut records connected to the other element, and a pair of twistable spring blades on which said needle arm and stylus holder are mounted for independent operation, said spring blades also holding said elements in predetermined normal position.
18. An electric phonograph reproducer comprising a casing adapted to be operatively mounted ona supporting arm, a pair of stylus members carried by casing and projecting through open-v ings in the bottom thereof, so that either member may be placed in playing contact with a record, one of said members being adapted to play lateral-cut records and the other member being operable on vertical-cut records without adjusting the position of the casing on its supporting arm, a pair of electric elements in said casing, said elements being arranged in variable inductive relation and adapted to be connected in circuit, and means whereby the operation of one stylus member vibrates one-of said elements and the operation of the other member vibrates the other element.
19. In a phonograph reproducer for vertical-cut records, a casing provided with an opening at the bottom, a stylus member mounted in said casing for vertical movement by a vertical-cut record opening, resilient means surrounding said member for closing said opening and damping the vibrations of said member, and means for converting the movements of said member into electric impulses.
20. An electric phonograph device comprising the combination of a horizontally pivoted shaft, a stylus holder connected to said shaft and adapted to vibrate laterally,.a stationary element, a second element connected to said shaft to vibrate therewith, said elements being operatively associated to produce electric impulses when the second element vibrates, and elastic damping means surrounding said shaft;
21. In a phonograph reproducer for vertical-cut records, a casing provided with an opening at the bottom, an element supported horizontally in said casing for vibratory movement in a vertical direction, astylus member secured to said element for vertical movement by a vertical-cut record groove, said stylus member extending through said opening, resilient material surrounding said stylus member for closing said opening and damping the vibrations of said member, and means for converting the movements of said element into electric impulses.
22.111 a phonograph reproducer for vertical cut records, a casing provided Withan opening at the bottom, a flat resilient element supported horizontally in said casing for vibratory movement in a vertical direction, one end of. said element being secured and the other end being free to vibrate, a stylus member connected to the free end of said element and supported thereby for vertical movement by a vertical-cut record groove, said stylus member extending through said opening substantially at right angles to said element, resilient material surrounding said stylus member for closing said opening and damping the vibrations of said member, and means for converting the movements of said element into electric impulses.
ADOLPI-I A. THOMAS.
US304642A 1928-09-08 1928-09-08 Electric phonograph reproducer Expired - Lifetime US1992727A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2423208A (en) * 1944-05-30 1947-07-01 Rca Corp Electrostatic pickup
US2465288A (en) * 1944-03-31 1949-03-22 Rca Corp Capacity type pickup

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2465288A (en) * 1944-03-31 1949-03-22 Rca Corp Capacity type pickup
US2423208A (en) * 1944-05-30 1947-07-01 Rca Corp Electrostatic pickup

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