US895853A - Sound-amplifier for phonographs and talking-machines. - Google Patents

Description

PATENTED AUG. 11, 1908.

J. H. J. HAINES, SOUND AMPLIFIER FOR PHONOGRAPHS AND TALKING MACHINES.

APPLICATION FILED APR.25,1908.

. stylus bar and UNITEI) sTATEs PATENT OFFICE;

JOHN H. J. nAmEs, or'nnw von r, NY.

I SOUND-AMPLIFIER FOR rHo oGRAPHs AND'TALKING-MAGHINES.

To all whom it may. concern: 1 1

Be it known that I, J oHN H. J. HAIN s, a citizen of theUnited States, residing at the city of ew York, in the boroughof Manhattan and State of New York, haveinvented certain new and useful Improvements in Sound-Amplifiers for Phonographs and Talkin'g Machines, of which the following is a full, clear, and exact description.

This invention relates to talking machines, and has special reference to a type of device for amplifying the reproduction of sound from a record cylinder or plate, comprising a friction roll and shoe introduced between the the diaphragm, whereby the vibrations of the stylus are reproduced in the diaphragm in an amplifieddegree.

The object of my invention is to provide a construction of amplifier which will in crease the loudness of the reproduction very considerably without loss of definition or articu lation.

.A further object of the invention is to provide means whereby the degree of loudness of the reproduction can be varied at willand by simple mechanism and manipulation.

In carrying out my inventlon l utilize a form of shoe on the friction roll, which en-.

compasses more than one-half ,of the circumference thereof, and I connect one end of this shoe with the stylus lever in such a way that the outward thrusts of the stylus created by the vertical undulations in the record groove, drive the shoe into intimate contact with the roll, while the friction roll and shoe are caused to bodily followthe stylus in its inward strokes, permitted by the depressions in the record groove. The undulations in the record groove are made up of crests and depressions of varying depth and shape, and I have found that by so organizing my lever system that the crests of the record groove will act directly to increase the friction of the shoe, the sharpest and clearest reproduction is obtained. At the same time the arrangement must be such that when the stylus enters a depression in the groove, the friction shoe and roll will follow it, so that the shoe will receive the full eifect of the 1 thrust caused'by the next succeeding crest.

'lhis following-up action of the roll and shoe therefore increases ther loudness, but it also retains the purity or definition because it overcomes any tendency of the shoeto rattle or loosen from the 'roll during the recessions or inward strokes/of the stylus.

Specification of Iietters Patent: Application filed April 25, 1908. semi No. 429,122.-

' dulations of Patented Aug. 11,1963.

My friejtion roll is carried at theendbfa swinging shaft as usual, and its weight i's'sulpplemented by. a-weighted nut applied tot 1e endof the's'haftin theu l v total weight at the end of the shaft being predetermined in proportion to the coefiicient of friction between, the roll and shoe,-so that when the machine is in operation, the vibratory system will be floating in stable equilibrium at a certain elevation or distance from the record tablet Where, the stylus Willbe in operative relation. to the record, and

the vibrations due to the rubbing of the shoe upon the roll will be at a certain constant rate suitable to cooperate with and augment the vibrations which are to be superposed thereon by the reproducing stylus. Under this floating condition, there will be no effective force applied to the stylus to compel it to follow the undulations of the record groove,

and 'I'therefore add to-the vibratory system a supplemental weight or spring so applied as to create a tendency of the'roll and shoe to press the stylus against the record surface, thus compelling the stylus to follow the unupon-the friction shoe. This extra weight or spring, therefore, su plies the'means for causing the friction roli and shoe to bodily follow the movements of the stylus bar. But it must be and is so associated with the vibratory system that the vibrations of the stylus are not absorbed'thereby, but on the contrary are devoted entirely to varying the grip of the shoe upon the roll. i be more specifically The invention will described in connection with the accompanying drawing, in which: Figure 1 is an end elevation of a portion of a talking machine and my improved amplifyingattachment, some arts being broken away. Fig. 2 is a plan of the mechanism at the end of the swinging shaft. trates a modification of the stylus bar.

'1. is a record "tablet in the form of'a cylinderw 2 is a framecarrying the speaker comprising essentially a diaphragm 3 and the amplifying devices interposed between the ,dia phragm and the'record.

4 is ashaft commonly found in this type of machine, made in two sections connected by a universal joint, one section being driven by means of a belt or gearing from the motor 1-10 of the machine, and which is not illustrated herein, while the other section which is the record-groove and to. react Fig. 3 illusf goted at 6 in the frame.

shown, is adapted to swing freely at its outer end by reason of the universal joint referred to,'but is supported in a crank-arm 5, piv- Near the extremity of shaft 4 and in the 'same plane with the center of the diaphragm 3 is mounted a wheel or roll 7 of amber or other similar material, preferably having a grooved periphery which is embraced by a shoe having an inner surface corresponding to the shape of the groove in the wheel andbeing of hard rubber or other similar material adapted to afford a certain amount of friction when the wheel and shoe move with respect to each other. This shoe embraces more than one-half of the circumference of the roll and is preferably made in two sections 8 and 8 hinged together at 9. A friction device which thus embraces more than half of. the circumferstylus lever in Fig. 1 is in the form of a bell-- crank, while in Fig. 3 it is straight. Both forms are provided with a threaded rod 15 having a'fingenpiece. 16 by which it can be turned, the extremities of the rod being .pivotally connected the end of link '11.

mounted in bearings, and there being a nut 17 working on the rod and itself-held from rotation and guided by a second rod 18. The nut 17 has an extension to which is It will be seen that by turning the threaded rod 15, the angular relation of the link 11 with respect to the shoe and the axis of the roll can be changed. Thus, by moving the nut 17 outward, the link more nearly approaches a radial line with respect to the shaft 4, and the thrusts of the stylus bar towards and away from the shoe will be more direct and effective, resulting in louder'reproduction, whereas a movement of the nut 17 inward, will throw the link 11 into a position more remote from the radius of shaft 4, resulting in less effective movements of the stylus bar and correspondingly weaker reproduction.

The extremity of the shaft 4; is threaded to receive a weighted nut 19 such as is commonly used on this type of amplifier. The weight of this nut, together with that of the other elements at the end of shaft 4, tends to swing the shaft downward against the shoe. The pivot pin 6 to which the crank arm 5 is secured, also carries another arm20 on the same side of the axis as the arm 5, and which is provided with a vertical pin :21 over which may be passed any required number of sec tions of a weight 22, which weight also'serves to throw the swinging shaft 4 downward. But it will be seen that this weight 22 presses u on shaft 4 through the bearing 23 and w He the shaft is given a downward tendency, movements so rapid and short as sound vibrations are not transmitted from the shaft to the crank arm and weight 22. For convenience in raising the vibratory systemto permit of the free movement of the carriage 2 to change the position of the speaker, the crank arm 5 is provided with ex tensions 24 and 25. The former is engaged, by the press lever 26 and lifted, which throws the latter against the stylus bar and removes it from the surface of the cylinder.

The parts are shown in running or operating position in Fig. 1. When the machine is not running, the shaft,4 is in a slightly lower position than that shown, but, as soon as it commences to rotate in the direction of the arrow, the friction between the stationary shoe 8, 8 and the roll causes the end of the shaft 4 to rise, the upward movement ceasing when the'friction between the shoe and roll has been reduced to the predetermined degree. This friction thereafter remains constant and represents a certain periodicity or rate of vibration of the roll, shoe and weight 19, which is communicated to the diaphragm through the link 10. So long as the speed of rotation and the weight, exclusive of the weight 22,1'emain constant, there will be no tendency of-the shaft 4 to either rise of fall after it once assumes its operating position, but these parts will remain in a floating condition and under a constant rate ofvibration. In this condition there is only a slight tendency of the stylus bar to press its point against the record, and such vibrations as I 105 would be imparted to the stylus bar by the undulations in the record groove would merely cause a chattering of the end of the shoe to which link 11 connected, against the periphery of the roll, and the reproduction would be very much distorted. For-this reason the weight 22 added and made sufficient to impart a decided constant inward thrust tothe point of the stylus directed from the shaft 4 through the roll, the shoe, the link 11, and the stylus bar. With this equipment it will be seen that the elevations or crests of the undulations in the record groove -will move the stylus outward and throw the end of the shoe against the roll, while the roll, together with the shoe, will fall and fol low the end of the stylus, into the depressions of the record groove. The result of this is that the most effective parts of the record will remain in more intimate contact with the roll, and there will be no lost motion between the shoe and the roll when the outward thrust of the stylus occurs. This action is analogous to that which takes place in a. microphone, wherein there is no make and break of the circuit between the contacts, but only a variation of pressure; the result is also similar, for in a make and break telephone-the speech is garbled by sputtering and is quite unintelligible, while, with variavion of pressure only, the articulation is perfect. So in friction amplifiers, the chattering which cccu rs when the vibratory system does not follow the movements of the stylus, is responsible for foreign noises and imperfect reproduction, whereas, in my device, with the more variation in pressure, the re reduction is perfectly clear. Therefore, cearness is obtained by the fact that the vibratory system follows the movements of the stylus, and loudness is obtained-by the fact that too friction is produced by the most effective part of the undulations in the record groove,

In most forms of friction roll amplifiers" used heretofore, there has been. what is known as a floating weight, being a weighted arm pivoted to some part of the frame and on which is pivoted the stylus bar. The function of this weight is to keep the point of the'stylus bar in contact with the record surface, rising and falling to compensate for any cccentricities thereof. Such a weight necessarily partakes of and absorbs the vibrations of the stylus bar produced by the record groove, and therefore detracts from or lessens the amount of vibration that is delivered from the bar to the shoe. It has also been proposed to apply this extra weight to the end of the shaft which carries the friction roll, by making the weight whir h corresponds to 19 in the present case, propor tionatcly heavier than is required to establish the constant friction or uniform rate of the shoe upon which the record vibrations are to be superposed. When the weight is thus located, the stylus bar is held against the surface ofthe record, but the operation is still defective because this added weight continues to absorb the vibrations of the st lus bar, making the latter do more work and consequently dampening the vibrations which are delivered to the diaphragm from the stylus bar. The problem therefore is to so a ply this additional weight which keeps the stylus against the record surface, that thefull effect of the vibrations of-thc stylus bar will be delivered, without dampening, to the friction shoe and diaphragm. This problem is solved by my invention wherein I apply the extra weight to the crank arm 5, or to some other element 'which bears downward upon shaft 4, and which is preferably stationary with rupect to said shaft. To more fully explain this method of applying this extra weight, it will be seen that shaft tr otates freely in the bearing 23, at the end of" crank-arm 5, and consequently there isno molecular contact between the crank-arm and the shaft, but merely a loose, surface contact. Such aloose or imperfect contact between these two bodies acts as a bar against the transmission of high vibrations, so that when such vibrations occur in the shaft, they will not be transmitted tov the crank-arm and weight. It follows from this that while the extra weight 22 will serve to hold the stylus bar against the record, it will not interfere with or dampen the high vibrations imparted to the stylus bar'by the undulations of the record groove, and the full effect of the latter will be directed against the friction shoe, and thence. transmitted to the diaphragm. In as much, however, as the end of shaft 4 with the weight 19, roll 7 and shoe 8, 8, are given a constant bias towards the record cylinder, by the extra weight 22, the said shaft 4 with all of its parts will bodily follow the point of the-stylus into the depressions of the undulatory sound groove, the whole vibratory system, exelusive'of the extraweight 22, thus partaking of the sound vibrations. This, as before pointed out, prevents the shoe 8 from breaking contactwith the surface of the roll, when the stylus falls into the depressions of the record groove, permitting only the weakening of the pressure of the shoe at such times. The same action also makes the crests of the undulations of the groove more effective since the thrusts against the shoe caused thereby begin at once at the basesof the crests. My improvement therefore eliminates all lost motion between the stylus bar and the friction wheel, and avoids dampening of the record vibrations, thereby affording a pure and loud reproduction.

What I claim, is 2- 1. In a talking machine, comprising a sty- Ins and a vibratory system through which the vibrations of the stylus are transmitted, a weight adapted to cause the stylus to follow the undulations of the record groove in combination with a vibration barrier interposed between the weight and the vibratory system.

2. In a talking machine, the combination of a record tablet, a diaphragm, a reproducingstylus, an amplifying friction system interposed between the stylus and a weight for holding the stylus against the record surface of the tablet, and a vibration barrier interposed between the weight and the vibratory system.

3. In a talking machine, a reproducing amplifier comprising a swinging friction roll 311k shoe, a weight applied'to the roll to give a p1 edetermined constant 'rate of vibration to the shoe, a stylus bar, an extra weight for causing: the stylus to follow the undulations of the record groove, 'and 'a vibratidn barrier:

interposed between the extra weight and the vibratory system.

' 4. In a talking machine, an amplifying device comprisin a swinging shaft carrying a friction roll an shoe, a diaphragm connected with one end of the shoe, and a stylus bar connected with the other end thereof, the latter connection being such that the outward thrusts of the stylus bar will increase the friction between the shoe and the roll, a Weight applied to the shaft to create a constant friction between the roll and shoe, and means whereby the roll and shoe will follow up the movements of the stylus bar.

5. In a talking machine, an amplifying device comprising a swinging shaft carrying a friction roll and shoe, a diaphragm connected with one end of the shoe, and a stylus'bar connected with the other end thereof, the latter connectionbeing such that the outward thrusts of the stylus bar will increase the friction between the shoe and the roll, a weight ap lied to the shaft to create a constant friction between the roll and the shoe, and an extra weight or its equivalent adapted to causethe roll and shoe to follow up the movements of the stylus bar, without itself absorbing the vibrations of the stylus.

6. In a talking machine, the combination of a rotary swinging shaft carrying a friction roll, a friction shoe embracing more than half of the circumference of said roll, a diaphra m connected to one end of said shoe, a sty us bar connected to the other end of said shoe,

means for adjusting the angular position of the link with respect to the shoe, for the pur* pose set forth.

8. In a talking machine, an amplifier comprising a friction roll and a friction shoe appl ed thereto, a diaphragm connected with one end of the shoe, a stylus bar, a link connecting the stylus bar with the other end of the shoe, and means for adjusting the point of connection between the stylus bar and the link, for theipurpose set forth.

9. In a talking machine, friction means comprising a roll and shoe, a stylus bar carry ing a threaded rod, a-nut movable along said rod, and connection between the nut and shoe, for the purpose set forth.

In witness whereof, I subscribe my signature, in the presence of two witnesses.

JOHN H. J. HAINES.

Witnesses.

WALDO M. CHAIIN, MARY S, HANDY.

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