US1499521A - Magnetic phonograph - Google Patents

Description

July 1 1924. 1,499,521

w. HAGEMANN MAGNETIC PHONOGRAPH Filed May 29, 1922 v s 7 14 L Mme/Mar;

' Patented July '1, 1924.

UNITED STATES 1,499,521 PATENT oFI-lcs.

WALDEKAB EAGEEANN, OF BEBLIN-LIGH TBFELDE, GEBHANY, ABBIGHOB 'I'O V01 HABOHINEN-AKTIENGEBELLS OHAFT, 01 BERLIN, Gm.

MAGNETIC PEONOGBAPH.

Application filed May 29, 1822. Serial No. 504,574.

To all whom it may concern Ije it known that I, Wamnuan Haas- MANN, a citizen of the Republic of Germany, residing at Berlin-Lichterfelde, Germany,

have invented certain Improvements in Magnetic Phonographs, of which the following is, a specification.

,Phonographs of the Poulsen type, in which the sound vibrations are recorded magnetically upon a fine traveling steel wire, depend, for the strength and the purity with which the sounds are reproduced, on the s eed of. the wire: the higher the speed of t 1e wire, within certain limits, the better the reproduction. Good results have not so far been obtained with a speed lower than three metres er second. As the machine ma be required to reproduce a speech of hal an hours or an l-iours duration, it is evident that a wire about 10,000 metres long and of considerable wei ht would be required for this purpose. a manipulation of such a bulk movin at a high speed, is connected with diflicu ties, articularly when the machine is used for dictating urposes and has to be handled by a technica ly untrained office staff. It is essential, therefore, that the wire reels and their crating mechanism should be constructed with great care so that a sudden stoppage and reversal of the movement can be accomplished with ease and certaint It is moreover essential that me chanica vibrations and consequent extraneous noises should be eliminated, and this is hardly possible with the usual snall reels of about cm. diameter which have to revolve with a great velocity and which therefore are a t to set up vibrations, in the bearings, that interfere with and hinder the recordin and the reproduction of the sounds.

%he object of the present invention is to produce an apparatus of this kind by means of which the wire can be run at the necessary speed without causing mechanical vibrations and without involvin difliculties in the manipulation of the mac ine, andthe invention consists in arranging two reels loosely on the same shaft, one at each side of a loose drivin pulley to which either can be coupled pulley.

by a s ight axial, relative displacement, the

wire being led over a guide ulley from the loose reel to the one coupled to the driving Means are provided for an automatic brakin of the reels as soon as the coupling is re eased.

By this arrangement the reels can be made large enough to'produce a wire motion of about 3 metres per second at a reel speed of from 3. to 4 revolutions r second. At this speed there will be no etrimental mechanical vibrations, and a sudden stoppa e and reversal of the reels can be effected wit out jerks and without undue strain on the wire and on the mechanism.

In the accompanying drawings the invention is illustrated by way of example,

Fig. 1 representing a side view of the arrangement, partly in section, and

Fi s. 2 an 3, horizontal sections of slightly di erent constructions of the same, showingrthe driving ulley in different positions.

we wire ree s 1 and 2 are rotatably but not slidably arranged on a rigidly supported shaft at opposite sides of a driving pulley 3 which is capable of rotar as well as of a slight axial movement. T e sound-recording wire 8 is led over a guide pulley 10 from one reel to the other and passes through a magnetic element 9 by means of which the sound is recorded and reproduced. The ulley 10 is held in a fork 16 the stem of w ich is slidably guided in a bracket 17 a spring 18 being arranged on the-stem so as to suport the pulley and keep the wire in uniorm tension. The element 9, together with the bracket 17 and wire guides 19 are carried by a base plate 20 which is secured to the free end 0 a supporting arm 11 which is pivoted at 21 so that it can be oscillated for coiling the wire uniformly on the receiving reel. The arm 11 is oscillated by a heartshaped cam 13 which revolves with a shaft 12, motion being imparted to the latter from the shaft 15 by means of a shaft 14 and suitable cars.

A driving pulley 3 receives motion direct from a motor 22 and can be coupled to either reel for winding the wire onto it, the other ulley being rotated in the opposite direction ythe unwinding of the wire. The couplin of the drivin pulley to either reel is pre erablyeifecte by means of axially arranged electro-magnets mounted symmetrically in the reels, the pulley 3 is made entirely or partly of iron so as to be attracted to the reel whose magnets are energized. The magnets 4 of the reel 1 are connected to a ring 23, and the ma ets 5 of the reel 2, to a ring 24. The windlngs of the ma ets are connected to terminals to which current is w and may be provided with supplied by means of suitable sliding contacts. The reel 1 is also fitted with friction elements 6, and the reel 2 with similar elements 7. These friction elements, which are sha d like bufiers, are actuated by. springs an bear normally, with sli ht iressure, a ainst the driving pulley 3 so -iat t 051088 movements are opposed and interdendent, are held stationary by the pulley. a one set of magnets is energized, however, the pulley will be attracted thereto, as shown in 2, and ap lied to one set of its friction e ements wit increased force, thefrictional hold of the opposite friction elements being weakened or released so that the reels can rotate, one with the pulley and the other in the opposite direction. As soon as the ma ets areswitched off, the ulley moves bac to the position shown in 3 and stops the movement of the reels. ven if the current is switched ofi direct from one set of magnets onto the other, the sto ping and reversal of the movement of the e ectric motor 22 thus controlled, though quick, will be suiiiciently gradual for eliminating any jerks or any overstrainin of the wire.

The slightly increa tension on the wire, and consequent adjustment of the pulley 10 in opposition to the sprin 18, at the stopping of the reels, can be uti ized for the operation of additional brakes controlle by means of levers from the fork 16. The'reels may be adapted for axial displacement instead of the riving pulley, and the friction elements as well as the magnets may be connected to the pulley instead of to the reels-with the same result.

The reels 1 and 2 can be of difierent sizes, detachable, flangedrims in which to aecommodatethe wire. Such a construction is shown in sonstructed according to the invention, the apparatus, besides being noiseless in operation, will require very little driving power.

I ii h h h t 1. ma etic one a avin wo revolubly m o unted r 'eels a d agtedto car ry the record wire, a revolubly mounted driven member, friction means carried by said reels and adapted to'normally restrain any movement thereof relative to said driven member, and means adapted 'to move said driven member with res ectto said reels so as to increase the hol of said friction means on one of said reels and decrease it on the other. l

2. A magnetic phonograph having two means for engaging adapted to carry a record wire,

revolubly mounted reels adapted tocarry the record'wire, friction means carri by said reels and adapted to normally restrain the movement thereof, a revolubl mounted driven member adapted to positively drive one of the said reels at a time,'the movement of said driven member to positively drive one of said reels being ada ted to cause the lessening of the frictional old of said frie tion means on that reel which is not being positively driven.

3. A magnetic phonograph having a sta-. tionary shaft, two se arated reels revolublyr mounted on the sai stationary shaft and adapted to carry a record wire, guiding means for the said record wire located! intermediate said reels, the said wire Being adapted to be so wound on the said reels that if one of said reels is revolved so as to wind up the record wire, the other reel is caused to revolve in the opposite diree tion, a driving pulley revolubly mounted on the said shaft intermediate the said reels and means mounted on said reels and cooperable with said driving ulley for rotation of the reels and means a a ted to laterally move the said pulley on tlie said-'shaft so as to cause it toengage either one of said reels and cause the ositive actuation thereof.

4. A magnetic phonograph having a sta-* tionary shaft, two revolzible reels adapted to carry the record wire and mounted on the said shaft, each of said reels having electroma etic means connected thereto, a drivin pu ey intermediate the said reelsand made of iron or the like, ther'said pulley being adapted to move on the said shaft when it is attracted by the electro-ma etic means on one of said reels, the said ufi:

e reel towards which it is actua ed to cause the revolution of the said ghee}: h h h .5. agnetic p onograp a'vin a stationary shaft,,two se arated reels re volubly mounted on the sai stationa shaft and iding means for the said record wire loca inter- .mediate said reels the said wire being adapted-to be so wound on the said reels that if one of said reels is revolved so as to wind up the record wire, the other reel is caused to revolve in the opposite direction, and a driving pulley revolubly mounted on the reel shaft.

A WALDEMAR HAGEIANN. Witnesses:

E. HOLTZERMAN, Amos Sonaonnnn.

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