US688610A - Phonographic recording apparatus. - Google Patents

Description

No. 688,6!0. Patented Dec. l0, I901.

T. A. EDISON. V PHONOGBAPHIC RECORDING APPARATUS.

(Application filed Mar. 17, 1899.) (No Model.)

m: NORRIS Pans cc. more-Lima, WASHINGTON, a c.

NITED STATES Par).

PHONOGRAPHIC RECORDING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 688,610, dated December 10, 1901.

Application filed March 17, 1899.

T ztZZ whom it may concern;

Be it known that I, THOMAS A. EDISON, a citizen of the United States, residing at Llewellyn Park, in the countyof Essex and State of New Jersey, have invented a certain new and useful Improvement in Phonographic Recording Apparatus, (No.1,003,) of which the following is a specification.

My invention relates to various improvements in apparatus for making phonographic records; and the object of the invention is to improve the sensitiveness and accuracy of the recording mechanism.

The invention consists in so arranging the diaphragm or other elementinfluenced or vibrated by the sound-waves as to normally relieve it of all or substantially all stress,whereby it will be maintained in substantial equilibrium and will be more sensitively recep tive and more accurately responsive to soundvibrations. t

In phonographic recorders as heretofore constructed the diaphragms or equivalent devices have either been placed under a strain by the compensating weight employed to cause the cutting or engraving tool to properly track upon the recording-surface and at the same time to accommodate any eccentricities or variations in the blank or in cases where no weight is employed for this purpose the pressure necessary to properly engage the cutting or engraving tool with the recording material to the requisite depth to record the movements of the diaphragm under the sound-vibrations of itself places the diaphragm under stress. These strains destroy to a great extent the sensitiveness of the diaphragm or other vibrating element, especially to the weak overtones of musical instruments, and prevent the accurate recording thereof.

In order to overcome the objection indicated, the invention consists in employing a counteracting-spring cooperating with the diaphragm and which counteracts the normal strains to which the diaphragm may be subjected, either due to the employment of the usual compensating weight or to the direct engagement of the recording device with the record, as with some types of phonographrecorders.

In the accompanying drawings, Figure 1 is Serial No. 709,448. (No model.)

a sectional view through a phonograph-recorder of the type employingacompensating weiglit, illustrating my present improvements applied thereto, including the employment of a secondary or auxiliary spring; Fig. 2, a bottom view of the same; Fig. 3, a section onthe line X X of Fig. 2.

In all of the above views corresponding parts are represented by the same numerals of reference.

1 is the usual cylindrical casing, having a top 2, provided with a nipple 3, to which the speaking-tube is secured.

4 is the diaphragm, held in place between the rubber buffers 5 5, and 6 the clampingring for forcing the top 2 upon the upper buffer.

7 represents the compensating weight, piv-c oted at 8, and 9 the recording-lever, carrying the cutting or engraving tool 10 at one end, which engages with the recording-surface 11, generally in the form of a cylinder. The lever 9 is pivoted at 12 to the compensating weight 7 and connects at its 'free end by a link 13 with a small disk 14, secured to the center of the diaphragm 4 in any suitable way, as by means of shellac. Preferably I employ an auxiliary spring 15, connected to one end of the weight 7, as shown, and at the other end by a link 16 to the working end of the lever 9. This spring tends to depress the cutting or engraving tool 10 with an additional tension into engagement with the recording-surface and prevents successive vibrations of the cutting or engraving tool from the effects of momentum or the actual jumping thereof when subjected to the effect of unusually powerful vibrations. An adjusting-screw 17 is employed for adjusting the tension of the spring when used.

Heretofore the tendency of the compensating weight 7 has been to exert a downward stress upon the diaphragm 4, and by reason of this stress the diaphragm is not affected sensitively by the vibrations, nor does it respond accurately thereto. I therefore provide for the elimination of any stress upon the diaphragm,whcreby it will be maintained in substantial equilibrium, for the reasons which I have explained. Witha device of this character either a counteracting spring or weight may be employed, the former being preferable with the specific form of recorder shown.

This counteractin zs rim 18 is secured to the bottom of the casing 1, passes abovea bridge 19, and at its free end bears beneath the disk 14, a section of rubber 20 or other elastic material being interposed between the spring and said disk to prevent any rubbing sounds from being recorded. An adjusting-screw 21 engages through the bridge 19 and bears againstthe counteracting-spring 18, whereby.

the exact stress or strain which is exerted upon the diaphragm 4 by the compensating weight 7 and the auxiliary spring 15, if used, may be removed from the diaphragm and taken up.

by the spring 18. In this way the diaphragm will be maintained in absolute equilibrium, normally as much so, in fact, as if there were @no connectionwhatever between it and the Therefore it. is in a' recording mechanism. condition to respond sensitively to vibrations of every character and to accurately record them. At the same time the connecting mechanism between the diaphragm and the cutting or engraving tool will be under stress, whereby thecutting or engraving tool will respond to all vibrations, however abrupt,without lost motion or false motions due to mo- .mentutn.

Having now described my invention, what I claim as new, and desire to secure by Letters Patent, is as follows:

1. In a phonographic recording device, the

combination with a diaphragm, of a record- .ing device connected therewitha counteracting-.spring'for counteracting the stress imposed npon the diaphragm by the engagevment of the recording device with the recording-surface, andan elastic cushion-between the counteracting-spring and the diaphragm,

.snbstantialiyas set forth.

2. In a phonographic recording device, the combination With a diaphragm, of a compensating Weight, a recorder connected with the diaphragm and said compensating weight, and means for counteracting the stress imposed upon the diaphragm by the compensating weight, substantially as set forth.

3. Ma phonographic recording device, the combination with a diaphragm, of a compensating weight, a recorder connected with the diaphragm and said compensating weight, and a spring connected with the diaphragm for counteracting the stress imposed upon the diaphragm by the compensating weight, substantially as setforth.

4. In a phonographic recording device, the

combination with a diaphragm, of a compenbetween the diaphragm and said weight, of

an auxiliary spring carried by said weight and connected With the recording devices, and meansfor adjusting the tension of said auxiliary spring, substantially as set'forth.

7. Ina phonographic recording device, the combination with adiaphragm, ofa compensating weight, a recordingdever pivoted to said weight and carrying at one end a cutting or engraving tool, a'link connecting the other end of said lever with the diaphragm, and an adjustable spring carried by the compensating weight and connected at its free end to the working end of the recording-lever, substantially as set forth.

This specification signed and witnessed this 10th day of February, 1899.

THOMAS A. EDISON.

Witnesses:

ALEXANDER ELLIOTT, Jr. JOHN F. RANDOLPH.

Images