US1747688A - Electrically-operated phonograph - Google Patents

Description

Feb. 18, 1930.

H. s. WORRELL ET AL 1,747,688

ELECTBICALLY OPERATED PHONOGRAPH- Filed Nov. 9. 1926 Fi Fig. 3. 2s 32 s2 25 I Io v u 4 fi I I? 50 54 p i7 1 52 35 @g 5s 34 v 4041 In vezztors .1266. Worrell 1% Patented Feb. 18, 1930 UNITED STATES PATENT OFFICE HOWARD S. WORBELL, OF ARDMORE, PENNSYLVANIA", AND EDWARD G. WHEELER,

OF BBIDGEPORT, CONNECTICUT, ASSIGNOBS TO DICTAPHONE CORPORATION, 013' BRIDGEPOBT, CONNECTICUT, A CORPORATION OF. NEW YORK nLnc'rnIcALLY-ornnawn rrronoonarn This invention relates to phonographs, and

Enore particularly to recording means there- Heretofore, there have been many proposals to provide electric recording mechanism for phonographs, but these are either impractical or require expert knowled e in their use. Hence, until the advent 0 the present invention, no electric recording dem vice for phonographs was ever marketed for sale to the general public. There are, of course, electric recording devices made for use in laboratories in recording master records, but these are unsuitable and impractical for use by the public generally.

An object of the present invention is, therefore, to provide a simple and eflicient electric recording device for phonographs and particularly for dictation recording machines.

In attaining the object, great difficulty was encountered in providing a recording instrumerit which could be readily adapted to different voices and conditions, and hence, an important feature of the present invention is the provision of improved damping means for the vibratory system of therecorder.

Other objects and advantages will hereinafter appear. 7

In the accompanying drawings, which showone form of the present invention, that at present preferred-- Figure 1 is a side view of a recording phonograph, showing the recording mechanism embodying the present invention in section.

Fig. 2 is a top plan view of the operating mechanism for the recorder, the casing shown in Fig. 1 being removed.

Fig. 3 is an enlarged View of the operatlng mechanism of the recorder.

I The phonograph shown in the accompanying drawings comprises a base 10 at one end of which there is a standard or side-plece 11 which supports a mandrel 12 for rotation. The mandrel 12. is adapted to support a rec- 0rd 13 which is adapted to receive an undulating helical groove, the undulations of which correspond with the sound waves recorded.

The recording device is carried by a carriage 14 mounted to slide transversely of the machine on guide rods 15 and 16, under the influence of arotating feed-screw 17 engag I ing a feed-nut 18 carried by the carriage.

The record is engaged by a stylus 19 carried in a stylus holder 20 pivotally mounted on pivot screws 21 in a weighted lever :22 which is pivoted on pivot screws 23in a bracket 24 carried by a plate 25, which in turn is secured to a plate 26 adaptedto rest in a socket 27 in the carriage frame 14. It will be understood that, as usual in recording devices, the weighted lever 22 tends to hold the stylus 19 against the record, and the bracket 24 and pivot screws 23 tend to hold the weighted lever against lateral movement but permit free up-and-down movements to per mit the stylus to accommodate itself to records of dilierent diameters or to slight variations or eccentricities of a record.

As thus held in engagement with the record, the stylus 19 and its carrying lever 20 are vibrated to record one. blank record, according to the present invention, bya rod 28 having a head 29 embracing a stylus lever 20 and secured thereto b pivot screws 30. The rod 28 passes upwar ly through the holes in the weighted lever 22, plate 25 and plate 26 to a position where it is secured to an armature 31 of an electromagnetic operating device comprising, in addition to the armature 31, a

permanent magnet 32 which is circular in shape and has poles 33 and 34. The poles 33 and 34 are connected to U-shaped pole- pieces 35 and 36 respectively, whose terminal portions 37 and 38 respectivelyarelocated on opposite sides of the armature 31. Between the U-shaped pole- pieces 35 and 36 and surrounding the armature 31 is a coil 39, the core 40 of which is provided with a fiulcrum 41 centrally located therein for the armature 31.

Since the armature 31 is located between r the permanent pole-piece terminals 37 and 38,

pole- pieces 35 and 36. Hence, the armature 31 will vibrate in accordance with the variations in the voice-currents induced in the coil 4 in unison with the armature so that the stylus without damping means.

will cut the record and leave therein a helical groove corresponding in its undulations to the vibrations of the armature.

The electromagnetic device and this peculiar arrangement of the armature per se is not claimed herein, for its equivalent is disclosed in the patent to Capps #441,396, which discloses the idea of having a magnetized armature, a permanent magnetic field with a magnetizing coil stationary with respect of the armature so that it does not add inertia to the armature and the vibratory system.

Fair results have been obtained in some instances of the use of the device as described But, in order that the device may be sold and used by the general public, which use must needs accommodate for voices of different intensities and timbre, a suitable damping device must be provided. This has been done by the present invention.

The damping device of the present invention' operates on an equalizing spring 42, which is mo inted at one end between rigid blocks 43 and 44 on the pole-pieces 35 by means of a screw 45 threaded in the polepiece 35. At its outer or relatively free end, the equalizing 'spring'42 has a hole through which the upper end of the rod 28 passes, and it is engaged on both sides by nuts 46 and 47 threaded on the rod 28 and adjustable therealong. This spring 42 tends to hold the rod 28 in an equalized stable position with'the armature 31 located midway betweenthe pole-piece terminals 37 and 38 when the stylus 19 is resting .on the record surface and, in doing'so, it resists the downward pressure produced on the rod 28 due to the pressure of v the weighted lever 22 which tends to rotate the rear end of the stylus lever 20 upwardly and the forward end, which is connected to the rod 28, downwardly. As above stated, thenuts 46 and 47 are so adjusted that when the stylus 16 rests onth'e record 13, the annature 31 is located in a midway position between the poleiece terminals 37 and 38.

In order to amp vibrations of the vibraory s stems comprising the rod 28, stylus lever 0, and, of .course, the sriring 42, the present invention interposes etween the spring 42 and the pole-pieces 35 a block 48 of felt or other -vibration deadening material, on the one hand, and a block of felt 49 between the spring 42 and "a backing plate 50 on the other hand, and provides means for var ing the density and hence the resiliency o the felt to meet varying conditions.

The means disclosed herein for accomplishing 'thistcomprises a movable plate 51 overlying a lock 49 of felt. :This plate 51 may be pressed'down toward the block 49 to .compress the same 'and,ot course, along with {the bloc .8. of 'felt, which is between the resilient spring 42 and the pole-pieces 35, by means of a screw 52 threaded in the bracket 44 and having its lower end engaging the plate 51. This screw 52 may be adjusted to obtain minor variations in the damping effect of the felt blocks 48 and 49 and, when it is in adjusted position, may be locked there by means of a lock nut 53.

To make majoradjustments in the damp ing mechanism, a screw 54 threaded in a bracket 50 also secured to the pole-piece 35 is provided. This screw 54 engages the outer end of the resilient strip 49, and when moved downwardly compresses felt blocks 47 and 48 at a. point farther from the mounting of the spring 42 than the screw 52, and thus more noticeably changes the damping efiect of the felt block. The screw 54 is locked in lace when adjusted by means ofa locknut 55.

Of course, when adjustments of the damping mechanism are made by changing the density of the felt block, the spring arm 42 is moved up or down, according to whether the pole blocks are allowed to expand or are caused to be compressed, respectively. This would destroy the centralization of the armature 31 between the pole-piece 37 and 38. Hence, when the damping device is adjusted to any material extent, it is necessary to re- 1 1. In an electrically operated'sound-recording device, comprising a stylus lever; a weighted lever for pivotalliy; supporting the stylus lever and adapted to old a stylus carried b the stylus lever inengagement with a recor an operating rod secured to the stylus lever; an armature secured to the operating rod; pole-pieces midway between which the armature should normally lie when the weighted lever presses the st his lover and the operating rod downwa yr toward the record; resilient means for counter-acting the said downward pull; and an adjustable com nection between said resilient means and the rod tope'rmit the rod to be adjusted to bring the armature to a position midway between the pole-pieces when a stylus carried by the stylus lever is in enga ement with the record.

'2. In an electrics y operated sound-recording device, comprising a stylus lever; a

weighted lever for pivotallsupporting the stylus lever and adapted to old a stylus carriedrlay the stylus lever iii engagement with a r800. {an-operating rod secured @M m 1,747,ese

lever to vibrate the same; an armature secured to the operating rod; adjacent polepieces midway between which the armature should normally lie when the weighted lever presses the stylus lever and operating rod downwardly toward the record; and aperiodic means for counteracting the said downward pressure on said rod and armature.

3. In an electrically operated sound-recording device, comprising a carriage; a stylus lever; a weighted lever pivotally mounted on the carriage and pivotally supporting the stylus lever and adapted to hold a stylus carried by the stylus lever in engagement with a record; an operating rod secured to the stylus lever; an armature secured to the operating rod, said operating rod and said armature being mounted for vibratory movements only and being held against other. movements;

adjacent pole-pieces midway between which the armature should normally lie when the weighted lever pulls the stylus lever and operating rod downwardly toward the record; and aperiodic means for counteracting the said downward pull whereby the armature maybe held midway between said pole-pieces.

4. In an electrically operated sound-recording device, comprising a stylus carrier movable toward and from the record to accommodate records of different diameters and to accommodate eccentricities of a record; an operating rod secured to said stylus carrier;

- an armature secured to the operating rod,

said armature and rod being mounted for vibratory movements only and being held against movement with the st lus carrier in its rise and fall accommodating records ofdifferent sizes or eccentricities of a record; adjacent pole-pieces midway between which the armature should normally lie when, the stylus carrier moves its stylus against the record; and means for adjusting the mounting of the operating rod to bring said armature midway between said pole-pieces when the stylus normally engages the record.

5. A recording device, comprising a carriage a stylus lever pivotally mountedin said carriage to accommodate its stylus to records of different diameters and to eccentricities of a record; an'operating rod secured to the styluslever; a vibratory member connected to the operating rod, said operating rod and said vibratory member beingmounted for vibratory movement only and being held against rising and falling movements with the stylus lever when the stylus lever is accommodating itself to records of difi'erent dithe stylus lever is in position to cause its stylus to engage a record.

6. In an electrically operated sound-recording device, comprising a stylus lever; an operatmg rod connected to the stylus lever; an armature C01 nected to the operating rod; and damping means for the stylus, operating rod and armature comprising means secured to the operating rod and blocks of vibration deadening material disposed on both sides of said means.

7. In an electrically operated sound-recording device, comprising a stylus lever; an operating rod connected to the stylus lever; an armature connected to the operating. rod; damping means for the stylus, operating rod and armature comprising means secured to the operating rod and blocks of vibration deadening material disposed on both sides of said means; and adjustable means for varying the density of said blocks of vibration deadening material.

8. In an electrically operated soundrecord ing device, comprising astylus lever; an operating rod connected to the stylus lever; an armature connected to the operating .rod; vibration deadening blocks interposed between said rod and a support; a leai disposed on one of said blocks of vibration deadening material; and a pair of screws engaging said leaf, one of said screws bein adapted to make majoradjustments of the density of the vibration deadening material, and the other of said screws being adapted to make minor variations of the vibration deadening material. Si ed at Bridgeport, in the county of Fair eld and State of Connecticut, this 2nd day of November, 1926.

HOWARD S. WORR'ELL. EDWARD G. WHEELER.

ameters or to-eccentricities of a record, said stylus lever being yieldingly urged toward the record whereby a thrust is produced against said operating rod and vibratory member; and means comprising a damped resilient member for counteracting said thrust causing said rod and vibratory member to occupy a predetermined position when

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