US2266781A - Sound recording and reproducing device - Google Patents

Description

1941- J. M. LUCARELLE ET AL 2,266,781

SOUND RECORDING AND REPRODUCING DEVICE Filed Aug. 3, 1940 2 Sheets-Sheet 1 lNVENTORS JO-S'ph M. Lu elle BY Charles 0 and .Dec. 23, 1941. J M LUARELL Em 2,266,781

SOUND RECORDING AND REPRODUCING DEVICE Filed Aug. 5, 1940 2 Sheets-Sheet 2 INVENTORS 2/8 f Joseph M Lucarelle ,5 BY Charles Eckland EYS t Patented 23, 1941 UNITED STATES PATENT. OFFICE SOUND RECORDING AND REPBODUCING DEVICE Joseph M. Lncareile and Charles Ecklund, Bridgeport, Conn., lslignors to Dictaphone Corporatrio?i New York, N. Y., a corporation of New Application August 3, 1940, Serial No. 350,458

19 Claims.

This invention relates to improvements in apparatus for transmitting vibrations between a record medium and a vibratable medium, such as sound recording and reproducing devices for use in dictating machines, phonographs, and the like, in which sound vibrations are transmitted between a recording medium, such as a cylinder or disc, and a vibratable medium, such as the vibrating air column of an acoustic phonograph, or the circuit carrying the electric vibrations utilized in an electric phonograph.

It is an object of this invention to provide simple and practical sound recording and reproducing devices for use in such apparatus. Another object of this invention is to provide mountings for such devices which permit vertical movement thereof in order to accommodate them to any eccentricities or variations in the size of the records with which they are used. A further object is to provide such devices with simple and prac-- tical means for determining the pressure exerted thereby on the sound records and to provide means for automatically altering this pressure when the devices are shifted from recording to reproducing conditions and vice versa.

Other objects will be in part obvious and in part pointed out hereinafter.

In the present application the invention has been shown as applied to a sound recording and reproducing mechanism of the acoustic type, such as is fully described in U. S. Letters Patent No, 1,606,744 to A. V. Bodine et a1., and Patent No. 2,016,505 to J. M. Lucarelle. It should be understood that although an acoustical type re cording and reproducing mechanism has been chosen to illustrate the invention, it is equally In the accompanying drawings, in which are shown two of the various possible embodiments of my invention:

Figure 1 shows an end view, taken partly in section on a transverse plane, of a portion of a dictating machine, incorporating one embodiment of the invention with the various elements thereof positioned for recording;

Figure 2 is a view similar to Figure 1 but with the elements shown in reproducing position;

Figure 3 is a plan view and section taken substantially on line 3 3 of Figure 1;

Figure 4 is a view similar to Figure 1 but of another embodiment of the invention showing the elements in position for recording;

Figure 5 is a view similar to Figure 4 but showing the elements in position for reproducing; and

Figure 6 is a plan view in section taken substantially on line 66 of Figure t.

Similar reference characters refer to similar parts throughout the various views of the drawwars.

The recording and reproducing mechanism shown in Figures 1, 2, and 3 comprises a carriage i0 slidabiy mounted on a guide rod it to travel over a record M which is rotated simultaneously with the traveling movement of the carriage in, so that a cutting stylus it, mounted on a recording and reproducing acoustical sound box structure, generally indicated at i5, produces a spiral groove in the surface of the record, which spiral groove constitutes a record of the sound which has been received by the acoustical devices This may be reproduced by permitting a ball-like reproducing styius it, also mounted on the sound box structure it, to track the spiral groove made by the recording stylus it. 1

Referring to the sound box structure ii, the recording and reproducing styli it and it, re spectiveiy. are mounted in a holder 20 secured to a diaphragm 22 in any suitable manner. The diaphragm casing or pan, 26 is provided with a sound tube 26 extending at its forward end into a housing 20 which is secured to the carriage ill. The manner of mounting the tube is such that the sound box structure i comprising pan 2t, diaphragm Z2, and styli i6 and iii, is capable of reciprocatory motion transversely of the record M, and is also capable of oscillating movement in a vertical plane and under certain conditions, as when reproducing, in a horizontal plane, this latter movement being necessary while reproducing in order that the reproducing stylus may properly track the record groove. Thus tube 28 acts as a pivoted lever rotatably supporting the sound box structure it.

In order to accomplish this object, a sliding sleeve 30 is carried within the housing 28, this sleeve may be moved into any one of three positions adapting the machine for recording, for reproducing, or to be idle, by means of a control slide with a small degree of clearance, is a,

sound tube supporting sleeve 48 which is so mounted as to be capable of a slight oscillation about vertical pivots 50 which have threaded engagement with the sleeve 48 and whose heads are positioned in apertures 52 formed in the slide 3!! and are rotatably mounted therein.

The sound tube 26 is mounted for vertical movement between a pair of horizontal pivots 54 and 56. The pivot 54 is threaded through the side wall of the sleeve 48 and engages a bushing or pivot socket 58 which is mounted in the side wall of the inner end of the tone tube 26. A corresponding bushing 60 is seated in the end of tube 26 in the wall thereof directly opposite the bushing 58 and in a position to cooperate with the pivot 56 which threadably engages the sleeve 48 at a point opposite the pivot 54. The axis of these pivots is parallel to the carriage rod I2 and the record I4.

Pivot 54 is adjusted and lockedin place by a lock nut 62 before the recorder-reproducer assembly I5 is inserted in the housing 28. Means is provided, however, for varying the adjustment of the pivot 56 during the operation of the machine so that the best setting for favorable recording and reproducing may be made during actual operation. To this end an aperture 64 is provided in the housing 28 exactly in line with the pivot 56 when the recording device has been set in recording position by moving the lever 32 to the position shown in Figure 1 of the drawings. In this position the recording stylus I6 is in engagement with the record cylinder I4. The

pivot 56 is locked in its adjusted position by means of a lock plate 66 which may be of warped construction and held in place by means of a screw 68. When the screw 68 is tightened, the lock plate 66 will bind the pivot 56 so as to hold its adjustment. The aperture 64 may be of very small diameter as it is only necessary that the pivot 56 be in a position for adjustment when the parts are in recording position. A small plug I8 may be employed to'close the aperture 64 after the parts have been adjusted.

An extension is provided for conducting the sound from the sound tube 26 to the cylindrical outlet I2 of the housing 28. This extension is formed of a slightly conical metal tube I4 having a partially ball-shaped portion I6 at its small end which is nested within the similarly-shaped inner end of the tone tube 26 and is pivotally supported therein by the pivots 54 and 56. The expanded end of tube 14 is adapted to slide back and forth within the outlet I2 of housing 28.

As mentioned above, the manually-operated control lever 32 is provided for shifting the apparatus from recording position to reproducing position, or vice versa, or to an intermediate neutral position when neither of the styli I6 and I8 engages the record I4. Further, as above-mentioned, the rocking movements of lever 32 are transmitted to the sliding tube 30 in the form of reciprocatory movements which cause the position of the tube to be changed as desired to bring either the recording stylus I6 into engagement with the record I4, as shown in Figure 1, or the reproducing stylus I8 into engagement with the record I4, as shown in Figure 2, when the lever 32 is in its respective extreme forward or backward positions.

In its intermediate position, the tone arm 26, with the attached casing 24, diaphragm 22, styli holders 20, and styli I6 and I8, is held elevated with respect to the record surface I4 with neither of the styli I6 or I8 engaging the record, by the engagement of a cam surface "I8 on the under side of the sound tube 26 with an abutment 88 on the lower side of housing 28. Further, the cam I8 and the abutment 80 serves to lift the styli on the sound box structure I5 away from the record as soon as the sound box starts to move from either of its operating positions, and this avoids damage being done to the record by the sliding movement of the styli over its surface. The apparatus thus far described is substantially the same as that disclosed in the above-mentioned patents to Bodine et al. and Lucarelle.

In accordance with the present invention, a weight is provided which is so designed and positioned that it is automatically connected to the sound box structure I5 to partially counterbalance the weight exerted on the record I4 when the apparatus is in recording position, as shown in Figure 1, and is automatically connected to add to the weight that the sound box structure I5 exerts on the record I4 when the apparatus is in position for reproducing, as shown in Figure 2.

To accomplish this, a U-shaped member 82 is provided extending rearwardly over the casing or pan 24 of the sound box structure I5. This member 82 is rotatably mounted on pivot screws 88 and 88 journaled in bushings 84 and 86, respectively, which are positioned on member 82 at intermediate points on the opposite side of the U. These pivot screws 88 and 98 are threadably mounted in lugs 92 and 84 projecting rearwardly from the. casing 28, as shown in Figure 3. Lock nuts 86 and 98 are provided on the pivot screws to lock them in position after they have been suitably adjusted. A weight I08 is mounted at the base of the U-shaped member 82 so as to be positioned above the casing 24 of the sound box structure I5. A horizontal pin I62 passes through the sound tube 26 at a point a little to the right ofits pivotal supports 54 and 56. This pin extends at either end slightly beyond the walls of the sound tube 26.

When the mechanism is adjusted for recording by moving lever 82 toward its extreme forward position, the cam 78 on the sound tube 26 rides up on the abutment 80, thus lifting the ends of the pin I62 above the forward or free ends of the U-shaped member 82 so that when the sliding sleeve 36 reaches its extreme rearward position, as shown in Figure 1, the ends of pin I02 drop down into contact with the free ends I64 of the U-shaped member 82. With this arrangement, the gravital force on the weight I88 tends to rotate the U-shaped member 82 in a clockwise direction, thus tending to raise the ends I64 of member 82 so that they push upwardly on the pin I62 and thus tend to impart a counterclockwise rotary movement to the sound tube 26 around its pivots 56 and 58, to counterbalance the mass of the sound box structure I5. The mass of weight I66 is so chosen that the downward pressure on recording stylus I6 is the exact amount desired for most efiicient recording. This arrangement is particularly advantageous because the sole connection through which the counterbalancing weight I exerts force on the sound box structure I is through the upward thrust of the ends I04 of member 82 on the pin I02. Any sound box structure will tend to resonate at some frequency. This frequency depends upon the particular design of the sound box but usually occurs somewhere within the range of frequencies desired to be recorded. If the sound box is permitted to vibrate at this resonance frequency, it tends to distort the recording, and, in addition, there isthe danger that the recording stylus I6 might jump off of the record surface if the vibration is particularly violent. When the sound box structure is interconnected with a counterbalance member, this entire structure likewise tends to vibrate at same natural resonance frequency which will differ from that of the resonance frequency of the sound box structure itself, but will have an equally deleterious result. With the present invention, as embodied in the structure above described, the harmful effect of natural resonance vibration is overcome. When the entire sound box and counterbalancing structure tends to vibrate at its natural frequency, the connection between the counterbalance and the sound box will be broken because the ends I04 of the counterbalance member 86 will mov away from the pin I02. This immediately kills the vibration effect because the natural resonance frequencies of the separated portions of the structure alone are different from that of the combined elements, so that when separated they no longer tend to vibrate at the natural resonance frequency of the combined structure. Similarly, when momentarily separated, if they should tend to vibrate at their individual natural resonance frequencies, the ends I04 of the counterbalancing member 82 will contact pin I02 and thus immediately kill this vibration of the individual members. By providing separable units, each element of which has a natural resonance frequency different from that of other elements and from that of the combined elements, any tendency to build up,considerable and harmful vibrations is eliminated.

When the structure, as above described and illustrated in Figures 1, 2, and 3, is adjusted for reproducing by moving manual control lever 32 toward its extreme right-hand or rearward position, as shown in Figure '2, the cam surface I8 and sound tube 26 ride up on the abutment 80 on the asing 28, thus lifting the ends of pin I02 from the ends I04 of lever 82 and thus carries pin I02 out of contact with member 82, so that when the sliding sleeve 30 reaches its extreme left-hand position, as shown in Figure 2, counterbalance member 82 is no longer restrained by the pins I02 and thus tends to rotate in a clockwise direction, causing the weight I00 to drop onto the upper surface-of the casing 24 of the sound box structure. This adds the weight of the mass I00 to the weight of the sound box structure I5, so that the pressure of the reproducing stylus I8 on the record is considerably increased over the pressure exerted when the recording stylus I6 is in contact with the record, or over the pressure which might be exerted by the sound box structure alone. By choosing the proper position of the pivots 88' and 80, the length of the lever 82 and the mass of the weight I00, the total weight exerted by the'reproducing stylus I8 on the record can be adjusted to any value necessary for most efficient reproduction. Thus, it can be seen that in accordance with the provisions of the invention herein described, a single weight is used both as a counterbalancing weight for recording and as an added weight for reproducing, and the application of this weight to the recording and reproducing device is so arranged as to prevent natural resonances from building up during the operation of the apparatus.

In Figures 4, 5, and 6, a simplified embodiment of the invention is shown in which separate weights are used, one acting as a counterbalance for recording, and the other acting asan added weight for reproducing. This simplified embodiment of the invention, however, incorporates the advantageous features of the embodiment just described in that it is so arranged that natural resonance frequency vibrations are prevented from building up to harmfully effect the operation of the phonograph.

The structure and operation of this embodiment is substantially the same as that shown in Figures 1, 2, and 3, except for the counterbalance and added weight arrangement, and similar reference characters are used to indicate all of the similar portions of these structures.

In this embodiment, shown in Figures 4, 5, and 6, an elongated egg-shaped or streamlined" weight 202 is secured to a lever 204 attached to a pivot shaft 206 which is journaled in the ends of the pivot screws 54 and 56, as shown in Figure 6, so that the weight 202 extends through the sound tube extension I4 into the cylindrical outlet I2 of housing 28. The other end 208 of lever 204, on theopposite side of the pivot 206 from the weight 202, curves slightly upward to contact a pad 2I0 of damping material secured to the inner surface of the upper side of sound tube 26 and slightly to the rear of the pivots 54 and 56. Thus,- end 208 of lever 204 exerts an upward thrust on the sound tube 26 due to the gravital force exerted on weight 202. This tends to rotate the sound box structure I5 in a counterclockwise direction about the pivots 54 and 58, to partially counterbalance the weight of the sound box structure and thus tend to de crease the downward pressure which the recording stylus I6 would normally exert on the record I4 due to the normal weight of the sound box structure alone. In this embodiment, this counterbalancing force is exerted at all times, whether the'apparatus is conditioned for recording, as shown in Figure 4, or conditioned for reproducing, as shown in Figure 5. The actual pressure of the recording stylus I6 on the record I4 may be adjusted to any desired value by proper choice of the weight 202. The positioning of the weight 202 within the sound tube 16 provides a simple arrangement which may be easily manufactured in mass production, and one which may be readily adjusted. The streamlining of this weight 202 permits it to be located in this sound tube with a minimum of obstruction to the passage of the sound waves therethrough.

In order to provide the added pressure on the reproducing stylus I8 necessary for eflicient reproduction, a U-shaped member 2I2 isprovided extending rearwardly over the casing 24 of the sound box structure I5. This member is mounted on pivots 2 and 2I6 threaded through two lugs H8 and 2 20 projectin rearwardly from the sliding sleeve 80. A U-shaped weight 222 is secured to the upper surface of this member 2I2.

provided with a tab 224 extending rearwardly beyond the edge of the casing 24, With this or. rangement, the member H2 is reciprocated forward and backward with the sound box structure I 5 as the latter is moved from its one extreme position of motion to the other. Likewise, due to its pivotal support on the sound box supporting slide 30, it may rotate about its pivots 2M and H6 so that the button 228 normally rests on top of the casing 24. When the lever 32 is moved toward its extreme forward position to condition the apparatus for recording, as shown in Figure 4, the sliding sleeve 30 and therefore the sound box structure I 5 moves to the right toward its rearward position to place the record'- ing stylus iii in contact with the record M. The cam surface 18 on the under side of sound tube 26 rides up on the abutment 80 and the housing 28, through the pan 24, lifts the weighted memher 2! 2 so that the projecting tab 226 is raised above a ledge 226 forming part of the carriage member I0. When the cam 78 moves beyond the abutment 80 to permit the sound box structure 15 to drop to its normal recording position, the weighted member H2 is supported by its pivots 2 M and M6 and the ledge 226 in inoperative position. When the lever 32 is moved to its extreme backward position, as shown in Figure 5, to condition the apparatus for reproducing, the tab 226 is lifted ofi of the ledge 226, thus permitting the member M2 to rotate in a clockwise dimotion so that the button 22% comes to rest on the top of casing 24, thus adding the weight of the member M2 and weight 222 to that of the sound box structure 95 so as to increase the pressure exerted by the stylus i8 on the record Hi when reproducing.

It will be seen, therefore, that this invention is' one well-adapted to attain the aims and objects hereinbefore set forth in a practical manner. Furthenthe construction is simple and not of a nature easy to get out of order, and one which may be easily assembled and adjusted for use.

As many possible embodiments may be made of the above invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

We claim:

1. In apparatus for transmitting vibrations between a record medium and a vibratable medium, in combination, a first lever, a translating device secured-to said lever and operably associated with said vibratable medium, a stylus mounted on said translating device and adapted to cooperate with said record medium, means pivotally supporting said lever to permit said device to oscillate about a first axis toward and away from said record medium, a Weight lever pivoted about a second axis, and means rigidly connected to one of said levers and pushing against the other of said levers to transmit by thrusting action only the gravital force of said weight lever to said first lever to oppose and thereby counterbalance the gravital force of said translating device.

2. In apparatus for transmitting vibrations between. a record medium and a vibratable medium,

3 in combination, a first lever, a translating device secured to said lever and operably associated with said vibratable medium, a stylus mounted on said translating device and adapted to cooperate with said record medium, means pivotally supporting said lever to permit said device to oscillate about a first axis toward and away from said record medium, a weight lever pivoted about a second axis, and resilient means secured to one of said levers to serve as a thrust connection between said levers resiliently to transmit the gravital force of said weight lever to said first lever in opposition tothe gravital force of said translating device.

3. In apparatus for transmitting vibrations between a record medium and a vibratable medium, in combination, a first lever, a translating device secured to said lever and operably associated with said vibratable medium, a stylus mounted on said translating device and adapted to cooperate with said record medium, means pivotally supporting said lever to permit said device to oscillate about a first axis toward and away front said recordlmedium, a weight lever pivoted about a second axis, thrust means rigidly connected to one of said levers and pushing against the other of said levers to transmit by thrusting action only the gravital force of said weight lever to said first lever to oppose and thereby counterbalance the gravital force of said translating device, and a pad of damping material interposed between said thrust means and said other lever.

4. In a sound translating machine, in combination, a first lever pivoted about a first axis, a sound translating device secured to said lever, a second lever pivoted about a second axis approximately parallel to said first axis, a weight secured to said second lever, and a thrust member rigidly secured to said second lever on the opposite side of said second axis from said weight, said second lever, second axis, and weight being so positioned with respect to said first lever that said thrust member pushes upwardly on said first lever between said translating device and said first axis. 5. In a sound translating machine, in combination, a first lever pivoted about a first axis, a sound translating device secured to said lever, a second lever pivoted about said axis, a weight mounted on said second lever on the opposite side of said axis from said translating device, and a thrust member rigidly secured to said second lever on the opposite side of said axis from said weight, said thrust member pushing upwardly on said first lever'at a point between said axis and said translating device.

6. In a sound translating machine, in combination, a first lever pivoted about a first axis, a sound translating device secured to said lever, a second lever pivoted about a second axis approximately parallel to said first axis, a weight secured to said second lever, a thrust member rigidly secured to said second lever on the opposite side of said second axis from said weight, said second lever, second axis, and weight being so positioned with respect to said first lever that said thrust member pushes upwardly on said first lever between said translating device and said first axis, and a piece of resilient material interposed between said thrust member and said first lever.

'7. In a sound translating machine, in combination, a first lever pivoted about a first axis, a sound translating device secured to said lever, a second lever pivoted about 'a second axis approximately parallel to said first axis and located on the same side of said first axis as said translating device, a weight mounted on said second lever on the opposite side of said second axis from said first axis, and a thrust member forming part of.

being adapted to push upwardly on said first lever at a point between said first axis and said translating device.

8. In a sound translating machine, in combination, a first lever pivoted about a first axis, a sound translating device secured to said lever, a second lever pivoted about a swond axis approximately parallel to said first axis and located on the same side of said first axis as said translating device, a weight mounted on said second lever on the opposite side or said second axis from said first axis, and an eifective hook member mounted on said first lever at a point between said first axis and said translating device, said member being adapted to hook onto said second lever at a point on the opposite side or said second axis from said weight to pull downward on said second lever at said point when the machine is recording.

9. In a sound recording and reproducing machine, in combination, a first lever pivoted about a first axis, a sound recording and reproducing device secured to said lever, means for moving said lever to condition said device for recording or for reproducing as desired, a second lever pivoted about a second axis approximately parallel to said first axis and located on the same side of said first axis as said recording and reproducing device, a weight mounted on said second lever on the opposite side of said second axis from said first axis, a thrust member forming part of said second lever on the opposite side said second axis from said weight, and means operative by said conditioning means when in recording position to position said thrust member against said first lever to push upwardly on said first lever at a point between said first axis and said recording and reproducing unit.

10. In a sound recording and reproducing machine, in combination, a first lever pivoted about a first axis, a sound recording and reproducing device secured to said lever, means moving said lever to condition said device for recording or for reproducing as desired, a second lever pivoted about a second axis approximately parallel to said first axis and located on the same side of said first axis as said recording and reproducing device, a weight mounted on said second lever 'on the opposite side of said second axis from said first axis, an effective hook member mounted on said first lever at a point between said first axis and said recording and reproducing device, and means operative by said conditioning means when in recording position to hook said mem-- ber on said second lever at a point on the oppositeside of said second axis from said weight to pull downward on said second lever at said point when the machine is recording.

11. In a sound translating machine, in combination, a first lever pivoted about a first axis, a sound translating device secured to said lever, a second lever pivoted about a second axis approximately parallel to said first axis and located on the same side of said first axis as said translating device, a weight mounted on said second lever on the opposite side of said second axis from said first axis, a thrust member forming part of said second lever on the opposite side of said second axis from said weight, said thrust member being adapted to push upwardly on said first lever at a point between said first axis and said translating device, and damping means in terposed between said thrust member and said first lever.

12. In a sound recording and reproducing machine, in combination, a sound recording and reproducing device, means adjusting said device to condition it for recording or for. reproducing as desired, a weight, means applying the gravital force of said weight to counterbalance the weight of said device when the latter is in one of its operative conditions, and means applying the gravital force of said weight to add to the weight of said device when said device is in the other of its operative conditions.

13. In a sound recording and reproducing machine, in comomation, a sound recording and reproducing device, means adjusting said device to condition it for recording or for reproducing as desired, a weight, means applying the gravit'al force of said weight to said recording and reproducing device to counterbalance the weight of said recording and reproducing device when the latter is conditioned for recording, and means applying the gravital force of said weight to add to the weight of said recording and reproducing device when said device is conditioned ror reproducing.

14. in a sound recording and reproducing machine, in combinatmn, a sound recording and reproducing device adapted to coact with a record positioned in said machine, means conditioning said sound recording and reproducing device to record sound on said record or to reproduce sound from said record as desired, a weight, and means operative simultaneously with said conditiomng means to apply the gravital iorce or said weight to counterbalance the weight 01' said recording and reproducing device when th latter is conditioned ior recording and to apply the gravitai rorce or said weight to add to the weight or said recording and reproducing device when the latter is conditioned ior reproducing.

15. In a sound recording and reproducing machine, in combination, a sound recording and reproducing device adapted to coact with a rec-' ord positioned in said machine, means pivotaliy mounting said device to move toward and away from said record, means conditioning said sound recording and reproducing device to record sound on said record or to reproduce sound from said record as desired, a weight, and means operative simultaneously with said conditioning means to apply the gravitai force or said weight to said devic to tend to move said device away from said record and partially counterbalance the weight of said device when the latter is conditioned for recording and to app y, the gravital force of said weight to said device to tend to move it toward said record and add to the weight of said device when the latter is conditioned for reproducing.

16. In a sound recording and reproducing machine, in combination, a pivoted lever, a sound recording and reproducing device mounted on said lever for movement toward and away from a record positioned in said machine and adapted to coact with said record, means conditioning said sound recording and reproducing device to record sound on said record or to reproduce sound from said record as desired, a weight, and means, operative simultaneously with said conditioning means, applying the gravital force exerted by said weight to said lever to tend to rotate it in the direction to move said device away from said record when the latter is conditioned for recording and applying the gravital torce exerted by said weight to said lever to tend to rotate it in the opposite direction when said deviceiis conditioned for reproducing.

between a record medium and a vibratable medium, in combination, a first lever, a translating device secured to said lever and operably connected to said vibratable medium, a stylus mounted on said translating device and adapted to cooperate with said record medium, means pivotally supporting said lever to permit said device to oscillate about a first axis toward and away from said record medium, a second lever pivoted about a second axis approximately parallel to the pivotal axis of said first lever, a weight secured to said second lever, first means rigidly connected to one of said levers and adapted to push' against the other of said levers when said pivotal axes are separated by a first predetermined distance to transmit the gravital force of said weight to said first lever to oppose and thereby counterbalance the gravital force of said translating device, second means rigidly secured to one of said levers and adapted to push against the other of said levers when said pivotal axes are separated by a second predetermined distance and transmit the gravital force of said weight to said first lever thereby to add to the gravital force exerted by said translating device, and means moving said pivotal axes relatively to separate them by said first predetermined distance or said second predetermined distance as desired.

18. In apparatus for transmitting vibrations between a record minimum and a vibratable medium, in combination, a first lever, a translating device secured to said lever and operably connected to said vibratable medium, a stylus mounted on said translating device and adapted to cooperate with said record medium, means pivotally supporting said lever to permit said device to oscillate about a first axis toward and away from said record medium, a second lever pivoted about a second axis approximately parallel to the pivotal axis of said first lever and located on the same side of said first axis as said translating device, a weight secured to said second lever on the opposite side of said second axis from said first axis, an effective hook-like member secured to said first lever at a point between said first axis and said translating device, said member being adapted to hook onto said second lever at a point on the opposite side 2,266,781 17. In apparatus for transmitting vibrations of said second axis from said weight when said pivotal. axes are separated by a first predetermined distance to pull downward on said second lever at said point and transmit the gravital iorce of said weight to said first lever to oppose and thereby counterbalance the gravital force exerted by said translating device on said record medium, said weight being positioned to rest on said first lever above said translating device when said pivotal axes are separated by a second predetermined distance to transmit the gravital force of said weight to said first lever thereby to add to the gravital force exerted by said translating device on said record medium, and means moving said pivotal axes relatively to separate them by said first predetermined distance or by said second predetermined distance as desired.

19. In a sound recording and reproducing machine, in combination, a first lever pivoted about a first axis, a sound recording and reproducing device secured to said first lever for movement toward and away from a record, means moving said lever to condition said device for recording or for reproducing as desired, a second lever pivoted about a second axis approximately parallel to said first axis and located on the same side of said first axis of said recording and reproducing device, a weight mounted on said second lever on the opposite sid of said second axis from said first axis, a thrust member forming part of said second lever on the opposite side of said second axis from said weight, said member being positioned to push upwardly on said first lever at a point between said first axis and said recording Q and reproducing unit and transmit the gravital force of said weight to said first lever to oppose and thereby counterbalance the gravital force exerted by said device on said record when said conditioning means are operated to condition said device for recording, said weight being positioned to push downwardly on said first lever at a point on the same side of said first axis as said device when said conditioning means are operated to condition said device for reproducing to transmit the gravital force of said weight to said first lever, thereby to add to the gravital force exerted by said device and said record.

JOSEPH M. LUCARELLE. CHARLES ECKLUND.

4 CERTIFICATE OF CORRECTION. Patent no, 2,266,781. December 2;, 1 1g.

JOSEPH n. LUCARELLE, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 15, for "serves" read -serve; page 5, first column, line 18, for "same" read -some-; page 6, first column, line 52, claim 18, for "minimum" read -medium; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 5rd day of March, A. D. 191 2.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

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