US2446324A - Recording and reproducing apparatus - Google Patents

Description

Aug. 3, 1948. u. 1.. DI GHlLlN l 2,446,324

RECORDING AND REPBODUCING APPARATUS I Filed May 26, 1943 4 Sheets-Sheet l 1948. u. L. Dl GHlLlNl 2,446,324

RECORDING AND REPRODUCING APPARATUS I Filed May 26, 1943 -4 Sheets-Sheet 2 Aug. 3, 1948.

U. L. DI GHILINI RECORDING AND REPRODUCING APPARATUS 4 Sheets-Sheet 5 Filed May 26, 1943 w Mwuld J L f r Filed May 26, 1943 4 Sheets-Sheet 4 RECORDING AND REPRODUCING APPARATUS Patented Aug. 3, 1948 RECORDING AND REPRODUGING APPARATUS Ulrich a. or Ghilini, BeverlyHills, Calif.; Alexander s. or Ghilini and Elston .di Ghilini, administrators of said Ulrich L., di Ghilinhdeceased Application May 26, 1943, SerialNo. 488,515 1 Claim. (01. jam-is) cutting of a like length of sound groove lineage per second on any or all positions of the recording disc, regardless of the changing diameter of same at the point of recording. Constant groove speed reproduction of sound utilizesthe same sound groove lineage per second as it took ior'the recording of same.

.Both recording and reproducing of sound as described above is accomplished in part by a constantly changing speed of the turntable on which the disc rotates. This compensates for the changing diameter of the disc at the point of recording or reproducing.

The general object of the present invention is to provide a constant groove speed recording and relatively free of friction, and-capable of bein operated .by amotor having .alow horsepower. Where the mechanical design is maintained =simpie, free of friction,andoperatedby a low horsepower motor, better fidelity ofrecording loan be efiected than is the case where more complicated reproducing apparatus capable of greatly increasing the amount of recording time obtainable on asimilar size disc used on standard recording machines of the 78 R. P. M. and 33 R. P. M. type, with a higher fidelity and more freedom from disc surface noises Without need .of so-called tone-compensation required in .the amplification systems used in conjunction with orthodoxmachines.

The apparatus of the present invention is especially designed to obtain a fluency or smoothness of operation and freedom from mechanical and motor noises. By means of the present invention, the recording speed is reduced considerably below the recording speeds heretofore employed in recording apparatus, with the result that the length of time during which recording may becarried out on a given size disc is markedly increased over that of usual practice. By decreasing the recording speed, i. e., the speed in sound groove lineage per second passing therecording stylus or reproduction needle point, the surface noises from the recording disc may be decreased.

I have discovered several important mechanical'construction principles which determine the fluency and smoothness of operation of a recording (apparatus, and have incorporated mechanical means in the apparatus consistent with these principles so as to produce a recording and reproducing apparatus of an improvedtype. The first of these principles is that the mechanical construction of the apparatus should be .as free as possible from inherent friction. The recording apparatus must be simple in construction,

apparatus having a higher inherentfriction-tand driven by a heavier motor is employed. :Where more complicated apparatus having higher jriction and usinga heavy motor isemployed, higher recordingv speeds are necessaryin, ordersto secure fidelity in recordingwvith.theresultithat increased surface noises .are obtained from the recording disc.

Of primary consideration .in-the construction of the apparatus is the problem of torque. ffllhe torque in .a recording apparatus increases-the friction tobe overcome, decreases .thesmoothness of operation, creates distortion in the recording, tends to produce overlapping of the soundtracks in recording, increases surface noise, andincreases the. tendency .ofthe. apparatus inrgproducing to fail to follow properly the soundtrack. The torquein the mechanical construction of a constant groove speed recording apparatus arises mainly from faulty. design of the driveffon the carriage of the apparatus.

In the apparatus of the present.invention,.,the lead screw is positioned relative 'tothe'supPOr-t for the tone arm on the carriage so as to greatly reduce the torque onfthecarriageyalsotherlistance between the lead screw and the motor carriagecarrying the tone arm is reduced asmuch as possible.

Other factors in the ap aratus of the present invention which tend to improve the fluen yand smoothness of operation. are that ,thedrivet'from the motor operates only the turntabledirectly, the power for moving the carriage beingtaken from the turntable rather than directly .from,the carriage. Furthermore, ,a turntable ,light E in weight is employed.

Another object of the present inventionis to provide asound recording .and reproducing-apparatus which is capable of beingoperated-to record eitherirom the insideto the outsideof'tlie disc, or vice versaif desired.

Another object. of the invention :is to provide a sound recording and reproducing apparatus-in which .a single recording headis employed -ior both the purposes of recording and playing back the recording, which single recording head .is provided with a simple mechanicallyactuated means for properly varying the Weight Qnthe recording head -for these difierent-purposes.

In theza'pparatus of the ,present invention provision is made for mechanically varying the weight on-the recording head-in order to provide forthe best possibleconditions .of operation for all types of recording'disc. -Means also "are'provided jzby which the recording head may be locked in position during recording so that it is capable of movement relative to the carriage only in a vertical plane and also for releasing the recording head during play-back operations so as to be capable of a limited horizontal movement relative to the carriage.

The sound recording and reproducing apparatus of the present invention, together with various further objects and advantages of the invention, will be fully understood from the following description of the preferred form of the apparatus. The following description is given in connection with the accompanying drawings, in which,

Figure 1 it a top plan view.

Figure 2 is a section on the line 22 of Figure 1.

Figure 3 is a side elevation with certain walls of the housing in section.

Figure 4 is a plan view with the top wall of the housing and with the turntable and recording head removed.

Figure 5 is a fragmentary perspective view showing certain of the control mechanism.

1 Figure 5 a, is an enlargement of the buttress thread of the lead screw.

Figure 6 is a fragmentary section of the feed mechanism in the released position.

Figure 7 is a similar view in the engaged position.

Figure 8 is a fragmentary section of the control mechanism for the attachments for playing standard records.

Figure 9 is a section through the recording arm on the line 99 of Figure 2.

Figure 10 is a section on the line l0l0 of Figure 2.

Figure 11 is a fragmentary section, mainly through the recording arm.

from the axis of the turntable 2 at a distance slightly beyond the radius of the turntable 2 or any disc record to be employed thereon. The

Figure 12 is a side view of the recording arm in the elevated position. v

. Figure 12a. shows the position of the yoke relative'to the tube of the recording arm in the elevated position of Figure 12.

Figure 13 is a similar view in the play-back position.

Figure 13a shows the relative positions of the tube and yoke of the recording arm in the playback position of Figure 13.

Figure 14.- is a fragmentary view of a modified form of engagement between the carriage and lead screw.

Figure 15 is a section on the line l5--l5 of Figure 14.

Referring to the drawings, the apparatus comprises a turntable 2, which may be of any usual or preferred construction, and preferably is light in weight to insure reduction in friction of the apparatus. The turntable 2 may comprise a disc portion 3 for the support of a record 4 and a stem. The stem is provided with a flange 5 by means of which it is bolted to the disc portion 3. The stem extends through the disc portion 2 and is there threaded to receive a nut 6 for clamping the record 4 in position. The stem extends downwardly into a housing 1 and is provided within the housing with a worm for cooperating with a worm wheel 8 on a shaft 9.

The shaft 9 extends substantially radially from the axis of the turntable and is geared to a lead screw l0, The form and position of the lead screw constitutes an important element of the apparatus of the present invention. The lead screw ID has a horizontal axis which is spaced lead screw 10 has two threaded portions H and 12. The threaded portions H and I2 are pitched in opposite directions to provide for driving of the carriage (hereinafter described) in opposite directions with respect to the turntable from the same direction of rotation of the lead screw. The spacing of the lead screw [0 with reference to the axis of the turntable serves the further function of permitting a reduction in torque and reduction of friction in the operation of the apparatus by allowing the carriage to be driven from a lead screw located substantially in the same horizontal plane as the point of support of the recording arm, as will be hereinafter more apparent.

The apparatus includes the side plates 13 and M, which mount two supporting rods or tracks 15 and Is for the carriage H. The carriage ll consists of a rectangular frame pivoted, as indicated at Ha, to the rear supporting rod or track 15. The rear supporting rod I6 is mounted directly over the lead screw I0 and parallel therewith, and the distance between the lead screw to and rod It should be made small, if possible, in order to reduce the torque arm connecting the carriage with the lead screw.

The double clutch includes two pivotal feed members 20 and 2|, each of which is pivoted to shaft I9 and is provided with threaded lead shoes 22 and 23 for engagement with the lead screw Hi; the shoe 22 being intended for forming a driving engagement with the threads I I of the lead screw, whereas the shoe 23 is intended for forming a driving engagement with the threads of the lead screw 12. Springs 24 and 25 are provided between the frame and the lead shoes for normally urging such members into driving connection with the threaded portions of the lead screw.

There is also provided a stop or regulator 2M having an adjustment screw 25a engaging the feed members for the purpose of governing the depth that the lead shoe enters the lead screw. I have found that a substantial reduction in friction in operation of the apparatus is obtained by preventing the lead shoe from setting too tightly into the lead screw.

Referring to Figures 14 and 15 of the drawings, I have shown a modification of the feeding mechanism for the carriage, in which the lead screw Illa is permanently in engagement with a gear 90. The gear is loosely journalled on the rod 92 supported by the carriage IIa. In order to regulate the feeding of the carriage, I provide a brake 93 connecting the gear 9U with the rod 92.

A clutch control means is provided, which comprises the shaft 25 journalled in the rear frame and carrying a sleeve 21 rigid therewith, from which there extends a rod 28, the ends of which rod contact cam faces 29 and 30 on the lead members 20 and 2|. When the rod 28 is in a horizontal position, it contacts the lead shoes so as to hold both of the lead shoes 22 and 23 in disengaged position. Rotation of the arm 28 in one direction allows one of the lead shoes to engage the lead screw in under the influence of its spring, whereas rotation of the rod 28 in the opposite direction permits the opposite lead shoe to engage the lead screw I 0. The clutch mechanism thus provides means by which the carriage may be released from driving position with respect to the lead screw and provides a means by which the carriage may be connected with the lead screw l0 so as to be driven radially towards the turntable connected to the lead screw In so as to be driven radially outwardly from the turntable H).

The carriage is provided with a roller 39 for supporting the free end of the carriage on the rod I5, the roller 30 being journalled in the frame. The carriage is also provided with an electric motor 3| having a gear reduction box, which is supported in the carriage frame by four rubber bushings 32. The motor 3| is provided with a driving shaft 3,3 including the rubber flex ible connection 34'.

To the shaft 33 is pivoted a friction wheel arm 35, which includes two side plates 35 and end spacer members 31. Journalled between the side plates is provided a shaft carrying a pulley 3&3 anda friction wheel 39. Pulley 3B is connected by a belt drive to to a pulley 4| on the shaft 33. The friction wheel 39 is supported in position beneath the turntable 2, so that when the friction wheel arm is pivoted upwardly the friction wheel engages the underside of the turntable 2 at a point lying on a line passing through axis of the turntable and lying parallel to the direction of transmission ofthe carriage I! In normal recording and reproducing operations with the apparatus of the present invention, the turntable 2 is rotated by the friction wheel 39, which in turn is driven by the motor iii. The rotation of the turntable 2 in turn effects rotation through the worms 3 shaft 9 to the lead screw H). An engagement between the lead screw Ill in one of the lead shoes 22 and 23 connects the carriage so that it is moved radially with respect to the turntable in operation. The radial movement of the carriage in turn alters the position of contact between the friction wheel 39 and turntable 2, so that in operation the speed of rotation of the turntable undergoes constant change as the friction wheel moves with respect to the axis of the turntable, the normal recording and reproduction thus being carried out with constant linear recording and reproducing speed.

The friction wheel arm 35 isprovided with a rod 42, which is connected to a spring 43, tensioned to normally pivot the friction wheel arm 35 into position to bring the friction wheel 39 into contact with the. turntable 2. A release control lever is provided including an operating member 44, which is attached to a cam 45 rigidly attached to the shaft 19 of the clutch control means. The cam 45 is shaped so that when the operating member 54 is rotated upwardly, as viewed in Figure 5, the cam engages the rod 42 on the friction wh'eel arm 35, depressing the friction wheel from driving contact withthe turntable 2. This action simultaneously rotates the shaft l9 of the clutch means to insure release of both driving lead shoes 22 and 23 from the lead screw It. In this position of operation, the friction wheel is disconnected from the turntable, the carriage is released from the lead screw and moved to any desired starting position.

The apparatus also includes a recording and re-- producing assembly, including a mounting plate 46 which is provided with two vertical mounting pins, by means of which the same is adapted to be detachably supported on a block 48 having bores 49 to receive the mounting pins 41. This block 48 is positioned on the carriage so as to lie at a point substantially vertically above the lead screw The vertical alignment betw n the point of support of the recording mechanism on the carriage carry pintles 52, to which is pivotally supported a control arm 52a. There is also provided a universally mounted recording head arm 53 carrying at its end the electric recording or reproducing head 54 having the usual recording or reproducing stylus 55. The recording head arm 53 includes the main tube 56 pivoted to the ends of pins 51 carried by the short sleeve 58. The short sleeve 58 in turn is pivotally mounted by the ends of the pintles 52, thus providing for at least a limited universal movement of-the recording head arm 53. This universal type of mounting has been found to constitute an important element in the design of apparatus for faithful reproduction of recordings made at low recording speed.

The control arm 52a is intended for weighting the recording arm 53 during recording operations. It is well understood in the art that more pressure is required on the stylus 55 during the recording rigidly connected to the carriage, whereas in reproducing operations it is desirable that the weight on the recordin stylus be reduced and at the same time the recording arm be loosely mounted on the carriage, so that its position is capable of being governed by the grooves of the record being reproduced. To permit the same recording assembly to fulfill these different conditions, the control arm 52a is provided. This control arm 52a has the yoke fill straddling the arm 53. The yoke 30 has a curved portion 5! adapted to closely fit the arm 53 when the weighting of the control arm 52a is allowed to be superimposed upon the recording arm 53. The control arm 52a is rigidly supported (as far as horizontal movement is concerned) from the carriage I1, and, thereby when its wei ht is imposedupon the arm 53, it in turn locks such arm 53 rigidly with respect to the carriage. The yoke 60 of the control arm is provided with an opening of sufficient size so that in one pivoted position of the control arm the recording arm 53 may assume the position shown in Figure 1311, where clearance is provided between the recording arm 53 and the yoke. In this position of operation, neither the weight of the control arm 52a is imposed upon the recording stylus, nor is the motion of the control arm 55 in any way restrained by the yoke 35; on the contrary, the control arm is free to be controlled by the recorded grooves on a record in reproducing operations. The bottom of the opening of the yoke is provided with a curved surface 62 for engagement with the arm 53, as shown in Figure 12a, when it is desired to elevate the recording arm from contact with the record in carriageshifting operations.

For controlling and holding the control arm 52a in its various intended operating positions, there is provided, as indicated in Figures 12 and 13, a cam 63 having a control handle 64, which cam 53 is mounted on a pin 65 carried by an ear 56 on the mounting block 48 of the carriage. Figure 12 of the drawings indicates how the rotation of the cam 33 by engagement with the control arm 52a elevates the control arm, and thereby the recording arm 53 into a disengaging position. Figure 13 illustrates how in the second position of the cam 63 the control arm 52:: is lowered to permit engagement of the stylus 55 with the record in reproducing operations while holding the weight of the control arm 52a of the arm 53. By furtherclockwise pivoting of the cam 63 to the third position, the weight of the control arm 52a is superimposed uponthe arm 53 and the apparatus positioned for recording operations.

In order to adapt the recording assembly to the best conditions of operation for records of differenttypes, I provide an adjustable counterbalancing weight 61 slidable into the end of the tube 53 andirictionally held in any adjusted position by the spring 63. I have discovered that for the best reproduction from different records, the Weight of the reproducing arm requires adjustment. The composition of the material used'in different records varies. Moreover, reproduction from different recordings on the same type of record'may also render it desirable to vary the reproduction pressure. By the adjustable counterbalancing weight 67, I have been able to find it possible to considerably improve the reproduction in practice. I have also found in numerous cases, for reasons not fully understood, that the adjustable counterbalance 6! may be used as a tone control adjustment, the amount of Weight imposed on the stylus during reproducing operationsvarying the pitch of the reproducing operations.

In order to adapt the apparatus for reproduction of standard records produced by constant rotary speed in recording, I provide two supple mental drives for the turntable 2. These two supplemental drives are indicated for the reason that there are two rotary turntable speeds commonly used in recording records. more particularly in Figures 3 and 4 of the drawings, to the left of the turntable axis there is mounted a stationary support supporting a shaft H. Theshaft H is provided With a gear 12 adapted to be engaged by a gear 13 on the shaft 33 of the carriage ll. Whenit is desired to use the apparatus of the present invention for reproducing records made by the constant rotary speed method, the carriage I1 is disengaged from the lead screw I9 and shifted to the left into position to engage gears 72 and 73, The friction wheel 39 carried by the carriage is disengaged from the turntable and at the same time the recording head assembly removed. A supplemental reproducing arm 74a is indicated in Figure l for such operations. In these operations the record is driven by one of two friction wheels 14 and 75. The friction wheels '14 and 15 are carried respectively by the two friction wheel arms 12a and 73a pivoted on shaft ll. wheels 74 and 75 are spaced radially from the axis of the turntable a proper distance to give two selective constant rotary speeds to th turntable upon operation of the motor 3|. These friction wheel arms carry the friction wheels 14 andv 75 and are provided with rods 16 and I1, by means of which the friction wheels may be pivoted into and out of engagement with the turntable by cams l8 and 19, controlled by operating members 80-and 8|.

Therecording and reproducing machine thus described possesses many advantages over those heretofore employed. The machine of the present invention may be constructed to operate satisfactorilyat a much slower recording speed than As indicated These two friction any other constant groove speed disc recording machine hitherto commercially sold. For example, with the apparatus of the present invention, recording of voice and music may be carried out at recording speeds of 2.5 inches per second; whereas the minimum recording speed heretofore employed was about 3.85 inches per second for voice and about 8 inches per second for the purpose of recording music. The standard 78 R, P. M. recording machines employ a recording speed of approximately 47 inches per second on the outside of the disc and 13 inches per second on the inside of the disc,

Furthermore, the standard recording apparatus is extremely heavy and impractical for home use.

With the apparatus of the present invention, I may record both voice and music over a period of approximately 3 /2 hours on a 16 inch disc, and this recording time may be increased if voice alone is to be recorded. The standard 78 R, P. M. recording machine records only for about 3.5 minutes on a 12 inch disc, whereas the 33 R. P. M. recording apparatus records for approximately 15 minutes using the 16 inch disc.

While the particular form of apparatus herein described is well adapted to carry out the objects of the present invention, various modifications and changes may be made coming within the scope of the appended claim.

Iclaim:

In an apparatus for recordingand reproducing sound by the constant groove method, the combination with a carriage, a stylus arm supported by said carriage, and a motor-driven friction wheel mounted on said carriage for driving said turntable, of a feed screw drivenby said turntable and having two separate oppositely pitched screw portions, and selective means for connecting said carriage selectively with the difierent portions of said feed screw including a separate half nut carrying arm engageable with each of said feed portions, said arms each being. provided with spring means normally urging the same into the engaging position, and cam-actuated controlmeans therefor simultaneously engaging both of said arms and operative in positions to maintain either or both of such arms in the released position.

ULRICH L. m GHILTNI.

REFERENCES orrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS Date Number Name 887,429 Rosenthal May 12, 1908 1,291,515 Hinckley Jan, 14, 1919 1,941,668 Ellman et a1. Jan. 2, 1934 2,076,298 *I-Iarris 'Apr'. 6, 1937 2,110,223 Harris Mar. 8, 1938 2,174,167 Rattray Sept. 26, 1939 2,199,420 Sparling May 7, 1940 2,235,301 Robinson'- 'Mar, 18, 1941 2,273,391 'Yerkovich Feb. 17, 1942 2,293,217 Rieber Aug. 18, 1942 2,293,220 Rieber Aug. 18, 1942 FOREIGN PATENTS Number Country Date 262,430 Germany; July 12, 1913 639,797 1 Germany Dec. 12, 1936

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