US1649483A - Phonograph reproducer - Google Patents

Description

Patented Nov. 15, 1927;

UNITED lvSTATES PATENT oEFlcE.a

HEBER s. NELSON, E sALT LAKE oiTY,`UTA1 1, AssIGNoR oF ONE-FOURTH To ROBERT MURRAY STEWART, 0E sALT LAKE CITY, UTAH.

rHoNoGRAPH Application filed April 9,

. reproduce the music, voice, .sounds of whatever is recorded', thusI providing an instrument for such purposes which will be extremely sensitive to actuating vibratory changes.

Another object is to provide av spool for the coil ofwire, whichy will not permit eddy currents of the transformer type.

Another object of the invention is to use' a single spool or winding and 'yet obtain the combined magnetic action of four pole pieces on the vibrating armature.

Another object'isto provide a-means of centering, balancing and adjusting the armature to the' most sensitive position, so as to prevent the armature 'from sticking to the pole pieces and to produce through the am. pliier with loudness and distinctness, with-` out distortion, such articulate vor other sounds' as may be imbedded on the surface of ya phonograph record.

With the foregoing and other objects `in view, the invention consists of certain novel features of construction, combination and `arrangement of parts, as will be more fully '35 described and. particularly pointed out in the appended claims. c

In order that my invention may be fully understood, I will proceed to describe it, having reference to the accompanying draws.

40 ings, in which- Figure 4 is a side-elevation of an electromagnetic pick-up constructed inaccordance with my invention. vFig. l1 is a transverse section of the same, on the' line 1 1 Fig'. 4c

l and looking in the direction indicated bythe arrows on said line. Fig. 2 is a longitudinal 4section of the same,through the center of the armature and the stylus bar, on the line lof 2 2 of Fig. 1 and looking in .thedirec- 5o tion indicated by the arrows on said line.

Fig. 3 is a cross sectional view ofthe same,'

through the cent/er, on the line 3 8 Fig. 4.

and looking in the direction indicated by the arrows thereon; Fig. 5 is an enlarged cross sectional view showing the method of pivot'- 'blocks b and b", which are secured to the lThis frame is of non-magnetic material.

REPRoDUoER.

ing the armature; Fig. 5^ is a side elevation of the armature and shaft. Fig. 6 is an enlarged cross sectional view showing a modied means of pivoting the armature. In said drawings H designates a permanent magnet of circular form, to its'extremities or poles h and ff are secured the U A .shaped pole pieces P and P by'gneans of screws lc c; these pole pieces support the spool S, onl which is wound the wire forming the coil of wire, the number of turns of wire being dependent upon the impedance of the circuit in which the pickup is to be used. This .spoolconsists of a non-magnetic oblong Itube with ovalend pieces, the tube is slotted at z Fig. 5 upon its upper side and its ends separated so as to prevent eddy currents from eii'ecting the magnetization of the armature A. This spool is held in p'lacel by 192e. serial No. 100,961.

spool Aat each end and fit into recesses cut into the pole pieces P and P at each of their four corners. This armature is supported b means of a shaft E. This shaft/,is supported at its ends by being run through apertures in the walls of the tube. Thel armature has slotted recesses stamped into it across its exact center to admit the shaft E. One end of the armature is connected to the stylus bar B. The stylus bar is slotted at y to receive the armature. The stylus bar is pivoted by means of screwsp p', Fig. 1, engaging in lugs n n. These screws p p are supported by the lugs o o from the frame F.

90 The pole piece P is secured to itl by screws A 1 11,'which hold the 'entire unit in the case.

-Thescrew t is. also tapped into the fra-me.

The screws t t are for the purpose of adjusting the tension of the springs sys which cen. ter and balance thel armature in its most sensitive position. The screws t t and the stylus bar' are provided with short lugs over whiclrthe springs s s are placed to keep them 4from'moving out of allgnment. `The 100 ends of the wire from the spool S are solderedtothe standards c c. These standards are provided with suitable set screws -for connectlng wires to the amplifier.. Theyl are also suitably insulated from each other and from the frame. A non-magnetic cover 'D 1s provided to 'protect the various working parts.

The operation of the electromagnetic pick- `upiis as follows: The stylus bar B is caused to vibrate by the needle following the groove engraved in the record. The stylus .bar vibrates the armature, which is polarized by the permanentmagnet H through the pole 'pieces P P', thus inducing a current or electrical impulses in the coll, which is transmitted to the amplifier. The poles of the U shaped pieces lP P being of opposite po- .larity adjacent to that end of the armature which is of north polarity will operate-one to repel and the other to attract that end of the armature. .will repel and the other attract'the opposite end of the armature, thus establishing magneticequilibrium and polarizing thearmature.' It follows that any slight vibration of the armature disturbs the e uilibrium of the magnetic circuit. above construction will cause the articulate or other sounds which are recorded to be reproduced with great force and distinctness,

owing, mainly to the attractive action of the polarized armature upon the -poles of the' magnet, and this result is obtained when only two opposite poles are u'sed as Well as when four are present.l The employment of four poles as shown', is preferred, however, be'-1 cause in this construction the, attractive and repulsive force of' both ends vof the armature is used. Iffor any purpose astronger field magnet is'desired the-permanent magnet may be re laced by an electromagnet. Y

It 1s obvious that the'instrum'ent may-be used as arecorder, for the reason that when' the. coil is" connected to thev output of a recording circuit and when a current or 'elec- Atrical impulse is sent throughl the coil W, it

magnetizes the armature A. It follows that in the passage of an undulating current eo j . I claim is: j

. of the phonograph type-,comprising a field through the coil, the armature will be attracted witha force equal to the repulsion and attraction of all four poles, and that the vibratory motion thus produced -will be transmitted through'the stylus bar to: the needle or engraving tool.

T he instrument will thus be seen to be lequally advantageous for u'se as a recorder; 'the magnet having anl intensifying' action A f1'. An electromagnetic reproducing'd'evice magnet, double pole pieces for. saidv field magnet, `one lmbof'each pole 'piece acting Similarly one of the poles .It is o vious that ,the

upon one end of an armature, and the other.'

`wire having freedom of motion about its axis and pivoted in said tube, said core constituting or being identical with said armature, a stylus bar capable of transmitting the vibra, tory motion of the needle tothe armature, or the reverse. f

recording device of the phonograph type comprising a field magnet, one limb of each pole piece acting upon one end of an armature; and the other limb of cach pole piece acting upon the opposite endof said armature, a coil of wire, a split non-magnetic tubewithin said coil of wire, a shaft within the core of said 'coil of wire having freedom of motion-about its `axis and piv' otel'l in said tube, said core constituting or being identical with said armature, a stylus bar capable of transmitting the vibratory motion ofthe armature through the stylus barto the needle or engraving tool.

3..An. electromagnetic reproducingand recording device comprising a permanent magnet, two pole pieces attached to the permanent magnet, a coil of wire wound around a -nonmagnetic spool to an impedance Suit- 'fable to the electric circuit in which the device is to be used, a centrally pivoted armature operating between the four poles of the two.

pole pieces and energized by them and connected to a stylus bar with a flexible device for maintaining the balance of the armature- 2.' An electromagnetic reproducing and.

4. An electromagnetic reproducing and recording device comprising a body ring and casmg, aA .permanent magnet, two pole 'pieces forming four poles, a. coil of wire wound around a nonmagnetic-tube to form 'a spool having through its center an armature which is supported by means 'of a shaftpivoted through its center inthe walls of the' tube, and connected with a Stylus bar which is capable of being adjusted.

5. An electromagnetic reproducing and recording 'devicefof the phonograph type comprising a body ring, a casing, a-permanent magnet mounted therein, two U shaped pole pieces attached to the permanent, magnet, a coil of wire wound to an impedance '(suitable to the electric circuit in whiclrthe device is tobe used) around a nonmagnetic slotted tubeshaving nonmagnetic end pieces thus forming a spool which spool is fastened within the two pole pieces, an armature within the spool centrally, pivoted with a1 shaft which is supported in the walls' ofthe nonmagnetic tube, said armature being connected toan adjustable stylus bar which will iexibl'y maintain the armature inv a properly balancedV position withinsaid spool.l

6. Anelectromag'netie phonograph reproducing and recording device comprising an adjustable stylus bar attached to an armature that pivots on a Shaft said shaft passing through the center of said armature and supported in holes in the walls of a slotted nonmagnetic spool around which'is wound a coil of wire, said armature extending beyond the ends of the spool and energized by thefour poles of two U shaped pole pieces which arel secured to a permanent magnet, said permanent magnet being secured to a body ring in which are also secured two insulated contact lugs for connecting with an electric circuit.

7. An electromagnetic phonograph r'eproducing and recording device comprising a stylus bar pivoted to a body ring with a device .for adjusting said stylus bar, said stylus bar attached to an armature Which pivots on a shaft passing through its center thus allowing for a rotary rathert n a lateral movement of the armature7 said shaft being spported in holes in the Walls of a nonmagnetictube, said tube being slotted in order to prevent eddy currents of the transformer type, said tube together with nonniagnetic end pieces forming a spool around which is wound, to an impedance suitable to the electric circuit in which the device is to be used, acoil of wire, the ends of the armature eX- tending beyond the ends of the spool and energized by the four poles of the two U Shaped pole pieces; said poles being secured to a permanent magnet .which is securedto a body ring in which arc also secured two ini sulated contact lugs for connecting with an electric circuit.

In'test-ilnony whereof, I have hereunto sei'l i my hand.

HEBER S. NELSON.

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