US2254519A - Phonograph recording device - Google Patents

Description

Sept. 2, 1941. J. R. FOUCH PHONOGRAPH RECORDING DEVICE Filed July 17, 1959 2 Sheets-Sheet l Sept. 2, 1941. J R POUCH 2,254,519

PHONOQRAPH RECORDING DEVICE Filed July 17, 1939 2 Sheets-Sheet 2 INVENTOR.

Patented Sept. 2, 1941 UNETED STATES PATENT UFFIQE 2 Claims.

This invention relates to improvements in phonograph recording, and mechanisms and devices for use therefor; the invention is described in connection with a device adapted for cutting a record on a disk under control of electrical signals; the invention is not, however, limited to this particular element, but may be applied to other purposes of a similar nature as will be apparent from the following specification and the drawings forming a part thereof.

One of the objects of my invention is to provide a means for holding a record blank which is to be cut, or to have impressed thereon, a continuous undulating track which varies in accordance with the signals to be recorded; this holding means being adapted to engage a suitable slot or opening in a co-operating record blank, and also being so arranged as not to interfere with the use of a record blank or playback record not provided with the above mentioned slot or opening.

Another object of my invention is to provide a method and means for driving th turntable of a phonograph recording machine through a friction drive, the component parts of which Still another object of my invention is to provide a method and means of readily changing the pitch of the cutting spiral on a phonograph recording machine; which change may be affected, according to one modification of my invention,

by a rapid interchange of lead screws for feeding the cutting mechanism traversely across the face of the record.

A still further object of my invention is to provide a weighted center piece which may be placed upon the phonograph spindle in such a manner as to hold the record blank or playback record in position in cooperation with the aforementioned holding means, and at the same time which is so dimensioned and shaped as to form a suitable hub for the collection of threads removed in acetate cutting. And yet another object of the invention resides in an arrangement bywhich the cutting head is raised from engagement with the disk when a predetermined point has been reached in the lateral travel 'of the head.

Other objects of my invention will be apparent in the following specification and the drawings.

In previous recording mechanisms, it has been common practice to provide a clamping member which may be placed over the phonograph spindle in order to prevent a record blank from slipping upon the turntable due to the frictional drag of the cutting stylus. Since comparatively great pressure on the clamp is required, I have provided a raised portion in the turntable adapted to engage a hole punched in the recording blank. A modification of my invention is to provide a pin, spring operated, in the turntable, which is so placed as to co-operate with a punched hole in the recording blank so as to hold the blank against slippage during the cutting operation. Conveniently, this pin and its associated punched hole in the blank may be disposed within the center portion of the record, that is, the portion which is not used for recording. By the use of a spring-actuated pin for this purpose, the turntable is adaptable for use with standard pressings, and with records which are not provided with the aforementioned punched hole. When a standard playback record, for example, is placed upon the turntable, the weight of the record is such that the pin is depressed, and the turntable presents the normal fiat surface for use with this type of record.

In the past, various types of drive mechanism have been proposed to be placed between the motor, or the motor gear reduction, and the turntable for the purpose of smoothing out small irregularities in the mechanical motor movement or in 'the gears so that the angular velocity of the turntable itself shall be as uniform as possible. This constant angular velocity is essential if unpleasant changes of pitch in the reproduced sounds are to be avoided. According to my invention, I provide the underside of the recordcarrying turntable with a ground and accurately polished surface, which surface is adapted to engage a surface covered with felt or other suitable material on an intermediate member, which said intermediate member is itself driven by the spindle from the motor or gear reducer. The mass of the turntable and the frictional characteristics of the material used are so correlated as to achieve the effect of a low-pass mechanical filter, so arranged as to prevent the transmission of the unwanted speed variations to the turntable itself.

, -Figure 4is aside It is thus apparent that the turntable is loose upon the spindle, and rides upon the aforementioned intermediate member. According to my invention, therefore, th turntable may be lifted off the spindle, and the intermediate member may likewise be removed, thu affording access to the lead screw and other mechanisms if desired. The lead screw, which I employ in the preferred form of my invention, is held by two conical members, one of which may be provided with a spring so that by pressing the lead screw against this member the spring may be compressed and the lead screw removed from the machine. This feature, therefore, provides a means of changing lead screws and thereby changing the pitch of the cutting spiral, or its direction, at will. 7

The clamping device normally used on apparatus of this type for holding the record in position has been replaced in apparatus constructed according to my invention by a weighted center. The dimensions of this center have been chosen so as to providean adequate mass for holding the record iii-place, and also to provide an external surface adapted to wind the cutting thread from an acetate record around the circumference of this center weight in a manner which makes the removal of the threads an extremely simple matter. Furthermore, this center piecemaybe provided with a beveled upper edge;'in a preferred form of my invention, I provide a projecting memberon the inside of the cutting head, which projecting member is adapted to co-op'erate with the bevel on the center piece in such a manner-that the head is raised and the stylus removed from its cutting position when the head reaches a, predetermined position in lateral travel.

'I have found that this arrangement presents many practical advantages over the device previously employed by me, which was to stop the lateral travel 'of the cutting head at this predetermined point, and to allow it to continue to rotate in contact with the recording disk; this previous method frequently resulted in cutting through the recording material and in permanent injury of the stylus and/or the'balan'ced armature of' the cutting head assembly In order that the operation of the device according to my invention shall be clearly understood, I append hereto drawings showing one modification of'a deviceconstructed in accordan'ce with this invention; it is to be understood that the annexed drawings and description are E illustrative and are not limitative of the invention. U

In "the drawings: i

Figure 1 is a perspective, partly in section, of a, recording machine constructed according to this invention. t

Figure 2 is, aside elevation of the upper portion of the apparatus showninFigure 1.

Figure 3, shows a phonograph'recording disk having an.,auxiliary,,hole punched therein.

view of the head mechanism shown'in Fig. 1.

, -Figu're 5 is a perspectiveYview-of the-head mechanism showingjthe method, of supporting theheadgis 1 --Figure' 6 is a partial section of the head mounting. T

Figure 7 is -a perspective view of the lever mechanism.

Figure 8 is a side view of the. head and arm showing the positions occupied in operation according to the invention.

In Fig. 1, a main frame I supports a phonograph spindle 2 which is adapted to be driven by motor 4 through suitable gearing 5. The spindle 2 carries, above the gear 5, an intermediate member 6, which may be provided with a felt surface 1, and an integral gear 8, adapted to engage a gear 9 on lead screw [0. This lead screw I0 is supported by conical members II and I2, which members are in turn supported by the frame I in any suitable manner. The member l2 may be provided with a spring l4, so arranged that the normal position of the member I2 is such that the lead screw is pressed firmly against the support H and rotated by the gear 9 in co-operation with the drive gear 8 above described. The spring I4 is arranged to provide sufficient pressure to overcome any tendency of the lead screw to compress the spring l4 in the normal operation of the apparatus. Riding on the lead screw I9 is the knife-edge member I 5, which is arranged to engage the threads of the lead screw and secure a movement of the arm IS in accordance with the rotation of the lead screw. Integral with the arm [6 is the arm II, which carries the cutting head i8. It is thus seen that the lateral travel of the head l8 in relation to the rotation of the spindle 2 is dependent upon the gear ratio between the gears 8 and 9, the pitch of the screw thread cut in the lead screw I 9, and the ratio of the lengths of arms l6 and I1. It can ,thus be seen that, without change of the gear ratio between the gears 8 and 9, the use of lead screws of different hand will reverse the direction of lateral travel of the cutting head, while the use ofa lead screw of finer or coarser pitch willprovide a greater or lesser numberof lines per inch on the record, cut in the direction deter mined by the hand of the lead screw thread.

In Fig. 1, the turntable I9 is shown'with a record 20 thereon. This record 20 may conveniently be in the form shown in Figure 3, where the record is provided with a center hole2I adapted to engage the spindle of the machine and with an auxiliary hole 22 is within the cir cle 24, which circle indicates the minimum di ameter which can be successfully used in recording; the maximum recording diameter is illustrated by the circle 25.

In Fig. 2, the record disk 29 is shown on the turntable l9. In this turntable a pin- 26 is arranged in the opening 21, and operating the pin-is the spring 28. The dimensions of the pin 26, the opening 21, and the spring '28 are so arranged as to allow the pin to be completely recessed within the surface of'the turntable I9 when desired. As shown in the figure the pin 26 engages the hole 22 in the record disk, and causes the record disk 20/00 rotate as an integral unit with the turntable l9.

The spindle 2 may be provided with a pin 29, adapted to engage a slot 30 in the intermediate member 6, thisslot being so arranged that when the member 6 is placed upon the spindle 2, the pin 29 engages slot 39, causing the member 6 to rotate with the spindle. The felt or other friction surface 1- engages the underside of the turntable l9, and provides a friction drive for the turntable, which is itself free to turn upon the spindle 2. The'coeflicient of friction of the material 1 to the metallic surface of the tumtable I9, together with the physical dimensions and weight of the said turntable, and the desired speed of rotation, determine the area of the surface! which is to be placed in engagement with the turntable to secure a desired mechanical filtering action between the drive spindle 2 through the member 6 to the record 20 on the turntable I9.

Above the record 20 on the turntable I9 is placed the holding member 3 I As previously described, this member serves tocollect the threads when the mechanism is used for recording by cutting into the surface of a disk. In addition to this function, the beveled or sloping edge 32 of the member 3| is adapted to engage the projection 34 on the near side of the cutting head I8. Thus, on approaching a predetermined minimum recording diameter, cutting from the outside towards the center, the cutting head, which is traveling laterally underthe influence of the lead screw I acting upon the knife-edge I5, is caused to rise due to the action of the projection 34 in traversing the sloping edge 32 of the member 3!; and in raising the head removes the stylus 35 from engagement with the recording surface of the disk 20. The position of the cutting head I8 under these circumstances is illustrated at IS, the lip 34' riding on the top of the member 3i, and the stylus 35' being raised clear of the surface of the record 28: this is also shown in Fig. 8. Subsequent to the disengagement of the stylus 35, further lateral travel occasioned by the lead screw causes the raising of the arm i'l through the continued rise of the head I8, and by means of the arm I6 disengages the member I5 from the threads of the lead screw It, thus arrestingfurther lateral travel of the head.

This operation of the raising of the cutting head I8 by the sloping face 32 of the member 3! is used when the direction of cutting is from the outside towards the center. When cutting in the reverse direction, the head travels beyond the edge of the disk 29, and a restraining member 39 is arranged to prevent the stylus from striking the surface of the turntable I9.

The member I5, which controls the swing of the cutting head by engaging the threads on the lead-screw I0, is engaged and disengaged by raising and lowering the arm I5, which also ra ses and lowers the cutting head at the same time through the arm I1, and thus engages the stylus 35 with the surface of the recording disk only when the lateral travel of the cutting head is operative. To secure this, the member comprising the arms I6 and Il may be pivoted at I3. Since the above-described method of disengaging the stylus from the record blank requires cooperation between an inclined surface and the lead screw to provide travel of a lifting member on this inclined surface, another hinge point may be provided in the arm ii, at Al, to allow the cutting head to be raised as described wlthout disengaging the member I5 from the threads of the lead screw I6. This second pivot po nt maybe also adapted to compensate for any inequalities in the record blank, or other causes of non-uniform vertical distance between the stylus 35 and the member I5. This arrangement of parts s shown in Fig. 1, where the cutting head I8 is shown pivoted to the arm H, which itself p voted at the point I3 adjacent to its uncture with r I6. i g ti shows a preferred mounting of the head I8 on the arm ll, where a portion of the head is inserted into the inverted U of the arm, and ivotally mounted thereto by the screws 41, which may take the form of pointed screws and locknuts as shown, or which may be any convenient type of pivot mounting. As shown in the section view Fig. 6, when the head is raised a predetermined amount, the top of the head casting strikes the end of the arm I1, so that any further raising of the head will cause the arm to pivot about the point I3 as previously described.

This whole movement is shown in Fig. 8, where the dotted positions I8 and I8 of the head I8 show the apparatus in use. The position I3 shows the head alone lifted, and the position I8" shows the head and arm lifted, the arm then taking the position I1, and the shoe I5 being in position l5, clear of the lead-screw I5. As described above, this sequence of operations may be carried out by the cooperation of the projection 34 with the inclined face 32 of the member 3I, or by the operation of the lever 36.

This lever 36 is shown in detail in Fig. '7, and

its relationship to the other parts of the mechanism in Fig. 4, which is an enlarged view of the apparatus shown in Fig. 1. As may be clearly seen in Fig. 4, the lever 36 is pivoted at 23, and the pin 38 rides on the under surface of the arm ll so as to support the lever in such a position that it clears the record 28, and yet the pin 39 is below the under surface of the head I8 so as to allow the latter complete freedom of movement.

On raising the lever 36 by the handle 31, the pin 39 engages the under side of the head I8, and raises it about the pivot 41., Further raising of the handle 31 causes the pin 33 to engage the upper surface of the arm I! in such a way that the lift exerted on the point 23 causes the arm IT to pivot about the point I3, and so raise the combination of arms I1 and I6 that the shoe I5 is lifted from the leadscrew I0, and therefore permit the free lateral travel of the head.

The improvements in recording devices here shown according to my invention may be employed in the following manner, in which, for example, a record is to be produced on an acetate blank, cutting from the outside towards the center.

The operator places a record blank on the turntable. Preferably, this is a blank of the type illustrated in Fig. 3, having the auxiliary hole 22 punched therein. The record blank is so placed on the turntable, or rotated thereon, that the pin 25, acting under pressure from the spring 28, engages the hole 22 in the record blank. The weight BI is placed over the spindle 2, and this weight co-operating with the pin 26 serves to secure the record 20 to the turntable I9 in such a manner that no relative movement between these two can occur during the cutting process.

The machine is then adapted for recording, and the operator may start the motor and engage the member I5 with the threads of the lead screw 1 D in such a manner as to commence the recording at the position 25 on the record disk 20. The

Should the operator fail to disengage the mem- V ber I5 from the lead screw I0, or otherwise stop the operation of the machine, before the predetermined point 24 of minimum recording diameter is reached, the projecting edge 34 of the cutting head I8 cooperates with the sloping face 32 of the member 3| to disengage the cutting stylus 35 from the record, as previously described. It will be seen thattheabove-described mechanism is so arranged as to raise the stylus from the surface of the disk before the shoe is raised from the leadscrew, thus preventing damage to the stylus or the record. In a similar manner at the start of the recording operation, the shoe is engaged with the leadscrew before the stylus reaches the surface of the record; so.that at the start of the cut the stylus already has imparted to it a lateral movement to cause it to trace a spiral path on the surface of the record.

While the above example describes the operation of a preferred form of av device constructed in accordance with my invention, it is to be understood that the invention is not limited to the particular sequence of operations or to the particular construction described.

Having now described my invention, I claim:

1. A recording apparatus comprising a rotatable table adapted to support a blank record disc, a lead screw, means for driving the table and lead screw, a pivotally supported upwardly and downwardly movable arm having a shoe at the free end thereof engaging the threads of the screw for driving said arm toward or away from the axis of the table, a second arm movable with the first arm; a cutting head hingedly connected to the second arm and having a stylus adapted to rest on a record disk supported by the table, and a hand lever pivotally mounted on said first arm for successively disengaging the stylus from the disc and the shoe fromsaid screw, said lever including a first finger projecting laterally from one end. portion thereof and adapted to abut against the undersurface of the cutting head for raising the latter when said end portion of the lever is raised, and a second finger projecting laterally from the opposite end portion of the lever and adapted to abut against the upper surface of the first arm after the first finger has raised the cutting head a predetermined degree 2. A recording apparatus comprising a rotatable table adapted to support a blank record disc, a member supported at the center of the table, extending above said disc, and provided with a cam surface, a lead screw, means for driving the table and lead screw, a pivotally supported upwardly and downwardly movable arm having a shoe at the free end thereof engaging the threads of the screw for driving said arm toward or away from the axis of the table, a second arm movable with the first arm, a cutting head hingedly connected to the second ,arm and having a stylus adapted to rest on a record disc supported by the table, abutment means cooperating with the cutting head and second arm for causing upward movement of the second arm after the cutting head rises a predetermined degree, and means on the cutting head adapted to engage said cam surface as the cutting head moves toward the axis of the table, to thereby successively disengage the stylus from the disc and the shoe from said screw.

JAMES R. FOUCH.

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