US1989198A - Phonograph - Google Patents

Description

Jan. 29,193.5.`

PHONOGRAPH Filed Sept. 21, 1935 /N VENTO/e C har/es -/uen lic/z ATTORNEY Patented Jan. 29, 1935 I I UNITED STATES PHONOGRAPH Charles Huenlich, Bloomfield, N. J., assignor to Thomas A. Edison, Incorporated, West Orange, N. J., a corporation of New Jersey Application September 21, 1933, Serial No. 690,368 u 22 Claims. (Cl. 274-29) My invention relates to business phonographs or dictating machines and is more particularly directed to the sound recording and reproducing instruments employed in these machines. Such ,5 machines are adapted to record upon a wax cylinder the voice of the speaker or dictator and to reproduce the recorded matter. The recording on the cylinder is accomplished bymeans of a suitable stylus or cutting tool bearing on the cylinder and connected to a vibratory diaphragm which is supported or mounted in a sound box. The sound box is connected to a speaking tube sothat the diaphragm is caused to vibrate in accordance with` sounds spoken into the tube. The vibrations of the diaphragm are transmitted to the stylus andfin consequence engrave a groove oflvarying depth upon the surface of the record tablet when the latter is rotated.

In such machines the sound box is usually pivotally mounted and the stylus bears against the record tablet with a pressure determined by the mass of the sound box and the relative position of the stylus and the sound box pivot. When the record tablet is rotated the stylus cuts into the material of the tablet and a force is generated against the stylus which tends to move the stylus out of the wax. The stylus will therefore sink into the wax until the force tending to move it outis equal to the force tending to press it into the Wax and an equilibrium is thereby created. 'Such a. structure therefore tends to cut a groove of uniform depth in the record tablet.

In such devices there is a certain minimum of weight which can be obtained in the sound box if the construction is to have reasonable strength. This fact has in the past definitely limited the minimum depth of groove which could be obtained with such a recorder. However, from a consideration of the frequency characteristics of such 40 recorders, it is desirable to have the mass of the sound box frame as high as possible in order to provide sufficient inertia to prevent vibration of the sound box frame with the diaphragm. The greater the mass of the sound box frame, the farther into thelow frequency part ofthe frequency band it is possible to record.

In the past it has been found extremely undesirable to make the sound box any heavier than could be avoided by good design in order that the depth of groove cut by the stylus might be as small as possible. It is desirable to keep the depth of groove small to avoid tearing of the record material by the stylus. It is also well known in the art that the more shallow the record groove 55 produced by the recorder, the lower will be the surface noise accompanying the reproduction. We therefore have two sets of conditions which indicate entirely different designs. From the standpoint of stability and frequency characteristics it is desirable to provide a sound box frame having a large mass. `On the other hand, considerations of surface noise and accuracy of engraving recommend a minimum pressure on the rec'- ord.

It has been suggested that a counterbalancing weight be applied to the sound box to overcome these diiiiculties. Such a counterbalancing weight would have the advantage of increasing the inertia of the sound box while simultaneously decreasing the effective pressure of the recording stylus upon the record tablet. Such a counterbalance would therefore also have the advantages of extending -the frequency response of the recorder, of decreasing the depth of groove and thereby the surface noise produced, and of rendering the sound box more stable and less likely to be moved out of its normal or proper operative position.

However, if a simple counterbalance is applied to such a recorder, new problems are encountered. If the counterbalance should be allowed to extend beyond the conflnes of the enclosing casing for the sound box, it might be accidentally touched or moved during recording with the possible results of spoiling a record and breaking the recording stylus. If, on the other hand, the enclosing casing for the sound box should be extended to cover such a counterbalance, it would render the assembly too large and cumbersome. Such a structure would tend to destroy the visibility of the record which is highly desirable, and would tend to take up too much space on machines of the type for which it would be designed, which machines should in general be as compact and neat as possible.

The principal object of my invention therefore is to provide an improved and novel construction for counterbalancing the part of and preferably the greater part of the weight of the diaphragm assembly during recording so that the groove cut on the record surface can be be made shallower, and more accurate and uniform, and will be less apt to be affected by irregularities or impurities in the record material.

Another object is to provide a. more effective counterbalancing of the diaphragm assembly so as to increase the frequency range of recording and the uniformity of recording over the entire range.

A further object of my invention is to provid a counterbalance structure having the above gbl characteristics and which is adapted to be fully enclosed within the sound box casing so as to be` protected against accidental upset or misadjustment. j

A still further object of my invention is to provide an improved counterbalance structure which may be readily adjusted to different eiective values without changing the relative position of the parts of the sound box.

Other objects and features of my invention will be disclosed in the following specification and the appended claims.

For a. clearer understanding of my invention, attention is directed to the drawing accompanying and forming part of this specication, wherein;

Figure l is an elevational view, partly in sec- I tion, of a combined phonographic recorder and reproducer assembly embodying my invention, the mechanism being shown as conditioned for recording;

Fig. 2 is an elevational view, partly in section of the combined recorder and reproducer assembly of Fig. 1 when it is conditioned for reproducing.

Fig. 3 is a plan view of they counterbalancing mechanism of the recorder;

Fig. 4 is a bottom plan view of the combined recorder and reproducer shown in Fig. 1; and

Fig. 5 is a sectional view taken approximately on the line 5-5 of Fig. 2.

The combined recorder and reproducer comprises a cup-shaped member 2 which acts as a frame for supporting the mechanism and which is designed to fit into a carriage 1 adapted to be moved transversely of a record tablet A as the latter is rotated. The sound box 4 comprises a circular chamber supporting a diaphragm 5 which is held in place by a gasket 5 of soft material. A stirrup 6 is secured to the diaphragm 5 and carries at its outer end a recording stylus '7. I'he sound box 4 is pivotally secured concentric with the cup 2 by a mounting bracket suitably secured, as by sweating or spot welding, to the sound box casing and comprising a pair of spring arms 4' properly drilled at their outer ends to receive the conical ends of a short pivot shaft 16, which is mounted in the bifurcated end 3 of a lug 3 depending from cup 2. A partially threaded screw 15 is provided to adjust the tension on the pivots. 'I'he top portion of the chamber 4 comprises a centrally drilled spherical boss 8 adapted to coact with the internal spherical end of a tube 9 thereby forming a universal joint` The tube 9 extends upwardly into a neck l0 fo`rmed on the frame 2 and thereby connects the sound box 4 to a speaking tube (not shown) adapted to lit over the neck 10. A suitably formed wire retaining member 11 is used to hold the tube in place on the sound box 4.

In the slot 3 of the bifurcated end of lug 3 a bracket 1'7 is pivotally mounted on the center portion of shaft 16. A floating weight 12 is pivotally mounted for transverse movement on the bracket 17 by a shouldered screw 18 passing through a boss 18 on the floating weight. A stylus arm 13 is pivotally mounted in the oating weight l2 by a pin 13 and carries a reproducing stylus 14 at its outer end. The end of the arm 13 opposite to that which carries the stylus is positioned at all times within the stirrup 6. The floating weight is provided with a central hole through which the stirrup 6 and recording stylus '7 may freely pass. An advance ball 19, preferably made of sapphire and having a spherical end portion for engagement with the record tablet is mounted on the floating weight.

A forked member 2l is pivotally mounted at one end about the center of the screw 15. At its other end the forked member 21 is pivotally connected to a pair of arms 22 turned up from an extension 25 of an annulus 25. A pin 23 secured in a block 24 which is fastened to the inner top portion of thecup 2 passes through the arms 22 and provides a pivotal mounting for the annulus 25. The annulus 25 encircles the tube 9. An adjustable weight comprising an annular member 26 is can'ied by the annulus 25. The member 26 is partially cut away and is provided around its periphery with a groove adapted to fit into the inner side of the annulus 25. The member 26 may be assembled to the annulus 25 by springing it inwardly until it will pass inside of the annulus 25.

When the apparatus is to be used for recording, both the sound box 4 and the floating weight 12 are allowed to swing downwardly until they take up the position shown in Fig.. l in which the recording stylus 'l engages the record tablet and in which the floating weight 12 is carried on the record tablet by reason of the contact of the advance ball 19 therewith. It will be noted that the advance ball 19 -is positioned slightly in advance of the recording stylus so that as the record tablet is revolved and a groove is cut by the recording stylus, the advance ball will ride over the uncut portion of the record tablet in advance of the recording stylus. The iloating weight has no part in the process of recording, the advance ball being used as a convenient means of carrying the oating weight in a position in which it does not interfere with the operation of recording. By reason of the pivotal connection of the counterbalance 26 with the sound box 4 it\will bei noted that whenever the sound box is moved upwardly, the counterbalancing weight 26 is moved downwardly and vice versa.

It will therefore be seen that the weight 26 acts as a counterbalance to the sound box and will reduce the effective downward pressure on the stylus, thus reducing the depth of groove as compared with that which would be obtained without the use of the counterbalance and at the same time increasing the inertia of the sound box assembly. Such use of the counterbalance as has been explained hereinbefore increases the range of response of the recorder, renders it more stable, and results in a smaller amount of surface noise in recording. It will be noted that by this construction the counterbalance is located entirely within the cup 2 and also wholly within the space which would be enclosed by a vertical surface defining the periphery of the sound box 4. The recorder mechanism is thus entirely protected and it is impossible to accidentally touch or otherwise disturb the mechanism during recording. This construction also renders Athe combined recorder and reproducer assembly very compact and does not increase its size appreciably overthat which is now in common use in dictating machines so that easy replacement of existing recorders is made poible.

Since a portion of the annular weght 26 is cut away, the eect produced by the counterbalance may be readily varied by turning this weight on the annulus 25. A considerable change in the magnitude of the effective weight of the recorder assembly may be obtained in the manner since the effective center of gravity of the weight 26 is shifted considerably by shifting its position; However such shift involves no chang in the relative positioning of the Various parts of the combined recorder and reproducer assembly and forms a convenientmeans of making this adjustment without taking up excessive space.

When it is desired to condition the combined recorder and reproducer assembly for reproduc-` therefore moves downwardly until it reaches the record. In this case the oating weight in which the reproducing stylus arm 13 is fulcrumed is held clear of lthe record and serves to bias the reproducer arm into engagement with the record groove for reproduction in the well known manner. By the construction explained above, I have provided a combined recorder and reproducer assembly in which the effective pressure on the recording stylus is counterbalanced during recording, the entire structure taking up very little more space than is now normally required in commercial combined recorder and reproducer assemblies not having this counterbalancing feature with its attendant advantages.

Having thus described my invention, I claim:

1. A sound box having a stylus. arranged to cut a groove on a record tablet of a depth proportional to the effective weight of said sound box, and a counterbalance for said sound box comprising a movable weight located above and within the space which would be enclosed by a vertical surface defining the periphery of the sound box.

2. A sound box having a stylus arranged to cut a groove on a record tablet of a depth proportional to the effective weight of said sound box, and a counterbalance for said sound box comprising a pivoted weight located above and within the space which would be enclosed by a vertical surface defining the periphery of the sound box.

3. A sound box having a stylus arranged to cut a groove on a record tablet of a depth proportional to the effective weight of said sound box, afulcrum for said sound box, and a counterbalance for said sound box located on the same side of said fulcrum as said sound box.

4. A sound box having a stylus arranged to cut a groove on a record tablet-of a depth proportional to the effective weight of said sound box, a fulcrum for said sound box, a pivotally mounted counterbalance for said sound box located on the same side of said fulcrum as said sound box, and al connection between said sound box and said counterbalance.

5. A sound box having a stylus arranged to cut a groove on a record tablet of a depth proportional to the effective weight of said sound box, a fulcrum for said sound box, and counterbalance for said sound box located above said sound box and on the salme side of said fulcrum as said sound box.

6. A sound box having a stylus arranged to cut a groove on a record tablet of a depth proportional to the eiective weight of said sound box, a frame for said sound box, and a counterbalance for said sound box located within said frame.

positioned on the same side ot said pivotal mounting as said sound box.

8. A sound box having a stylus arranged to cutl a groove on a record Vtablet of a depth proportional to the effective weight of said sound box, and a counterbalance for said sound box, said counterbalance being adjustable to change its eiective weight without translatory change of its postion in a lateral direction relative to said sound box.

9. A sound box having a stylus arranged to cut a groove on a record tablet of a. depth proportional to the effective weight of said sound box, and an adjustable counterbalance for said sound box located above and within the space which would be enclosed by a vertical surface denning the periphery of said sound box.

10. A sound box having a stylus arranged to cut a groove on a record tablet of a depth proportional to the effective weight of said sound box, a fulcrum for said sound box, and an adjustable counterbalance for said sound box located on the same side of said fulcrum as said sound box.

11. A sound box having a stylus arranged to cut a groove on a record tablet of a depth proportional to the eiective weight of said sound box, and a counterbalance for said sound box located above said sound box, said counterbalance being adjustable to change its eect without translatory change of its position in a lateral direction relative to said sound box.

12. A sound box having a stylus arranged to cut a groove on a record tablet of a depth proportional to the effective weight of said sound box, and a counterbalance for said sound box comprising a member rotatable to a plurality of positions, said member having unequal weight distribution with respect to its axis of rotation to change the effective value of said counterbalance.

13. A combined recorder and reproducer assembly 4comprising a sound box having a stylus arranged to cut a groove on a record tablet of a depth proportional to the effective weight of said sound box, and a counterbalance for said sound box comprising a movable weight located above and within the space which would be enclosed by a vertical surface dening the periphery of said sound box.

14. A combined recorder and reproducer assembly comprising a sound box having a stylus arranged to cut a groove on a record tablet of a .depthy proportional to the eiective weight of said sound box, a fulcrum for said sound box, and a counterbalance for said sound box located on the same side of said fulcrum as said sound box.

15. A combined recorder and'reproducer assembly comprising a sound box having a stylus arranged to out a groove on a record tablet of a depth proportional tothe effective weight of said sound box, and a counterbalance for said sound box locatedv above said sound box, said counterbalance being adjustable to change its effect without translatory change of its position in a lateral direction relative to said sound box.

16. A combined recorder and reproducer assembly comprising a frame, a sound box pivotally mounted on said frame and having a stylus arranged to cut a groove on a record tablet of a depth proportional to the effective weight of said sound box, a counterbalance pivotally mounted on said frame and within the space which would be enclosed by' a vertical surface dening the periphery of said, sound box, and a connection between said sound box and said counterbalance.

1'7. A combined recorder and reproducer assembly comprising a frame, a sound box pivotally mounted on said -frame and having a stylus arranged to cut a groove` ona record tablet of a depth proportional to the eilective weight of said sound box, a counterbalance pivotally mounted on said frame above and within the space which would be enclosed by a vertical surface defining the periphery of said sound box, and a connection between said sound box and said counterbalance.

18. A combined recorder and reproducer assembly comprising a frame, a sound box mounted on a pivot on said frame and having a stylus arranged toA cut a groove on a. record tablet proportional to the eiective weight of said sound box, a weight pivotally mounted on said frame above said'sound box; and an opposing angular movement connection between said weight and sald sound box.

19. A combined recorder and reproducer assembly comprising a sound box having a stylus arranged to cut a groove on a record tablet of a depth proportional to the effective weight of said sound box, a frame enclosing at least a portion of said sound box and having a pivotal mounting for said sound box, and a counterbalance for said sound box pivotally mounted on said frame and entirely enclosed thereby.

20. A device of the character described comprising a sound box, a`recording stylus and a reproducing stylus associated with said sound box and adapted to be-alternatively conditioned for operation on a record tablet, and a counterbalance for said sound box, said counterbalance being effective only when the recording stylus is conditioned for operation.

21. A sound box having a. stylus arranged to cut a groove on arecord tabletof a depth proportional to the effective weight of said sound box, a tubular member connected with said sound box, and a counterbalance for said sound box comprising a movable weight through which said tubular member extends.

22. A sound box having a stylus arranged to cut a groove on a record tablet of a depth proportional to the effective weight of said sound box, a tubular member connected with said sound box, and a counterbalance for said sound box comprising an annular weight located above the sound box, said weight being mounted `for movement towards and away from the sound box and said tubular member extending through said weight.

CHARLES HUENLICH.

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