US2113401A

US2113401A - Phonographic apparatus

Info

Publication number: US2113401A
Application number: US728238A
Authority: US
Inventors: Alfred N Goldsmith
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1934-05-31
Filing date: 1934-05-31
Publication date: 1938-04-05
Anticipated expiration: 1955-04-05

Description

April 5, 1938. GOLDSMITH 2,113,401

PHONOGRAPHIC APPARATUS Filed llay 31, 1934 4 Sheets-Sheet 4 INVENTOR fllF/FZOMMASA/FV BY 74% ATTdRNEY Patented Apr. 5, 1938 UNITED. STATES rnonooaarmc Arr-snares Alfred N. Goldsmith, New York, N. Y., assignor to Radio Corporation of America, a corporation of Delaware Application May 31, 1934, Serial No. 728,238

19 Claims.

The present invention relates to an improvement in phonographic apparatus, and particularly to control means for phonographic apparatus using records of the grooved type.

There are many varieties of phonograph records in commercial use at the present time, and it appears probable that additional variations will appear in the future. For example, commercial records of the grooved disc type are made at the 10 present time to operate at rotational speeds of 78 R. P. M. and 33% R. P. M.; records of both of these speeds are made in the lateral cut and in the vertical or hill and dale types; records of each of these four species are made to cover the 15 ordinary frequency range of about 120 to 3800 .cycles, and records are also made having a frequency range of from 60 to 7000 cycles. Further,

some records are made to play from the periphery toward the center, while other records are made 90 to play from the center toward the periphery. Records are being made including recorded frequencies to the order of 10,000 cycles, and such records present special problems in reproduction. In the reproduction of each of the aforesaid types of records, there are special problems to be met. For example, the direction of stylus movement in the lateral cut records is lateral;

.while the hill and dale type of stylus moves perpendicularly to the record, and, therefore, dif- 30 ferent types of pick-ups are required.

In the customary low priced commercial record designed for a speed of 78 R. P. M. and having a frequency range of 120 to 3800 cycles or thereabouts, there is considerable surface noise" of much higher frequencies, and when an amplifier is used in sound reproduction the higher frequencies must be filtered out. In the last type of record above referred to for reproduction from 60 to 7000 cycles, it is desirable to provide an 40 amplifier having a proper response over the entire frequency range and in some instances to have slightly greater response at the higher frequencies than at the intermediate frequencies.

It will be apparent that not only the speed of 5 rotation of the phonograph turntable but also the characteristics of the thermionic amplifier and of the magnetic pick-up, which are customarily used at the present time, must be changed according to the characteristics of the 50 records to be played.

Such changes have heretofore always been made manually as by switching circuits, exchanging reproducenetc. I

A still further problem in this respect is intro- 55 duced by a possible new type of record which would be rotated at a speed of about 50 R. P. M. which would have a very wide frequency range,

i. e., of the order of 60-to 10,000 cycles, which would have the grooves rather shallow and close- 1y spaced and which would require a very light pressure upon the reproducing stylus to avoid damaging the record as distinguished from the stylus pressure ofthe order of six ounces ordinarily used.

Heretofore, it has been found impossible to control the characteristics of the phonograph by the record itself, as records vary in thickness and diameter, and therefore any means co-operating with either the surface or the rim of the record was impractical.

In accordance with the present invention, I provide the phonograph spindle with control means for accomplishing the various operations before referred to, and provide the record with means co-operating with the control means on the spindle for actuating the control means in accordance with the requirements of the particular record being played as will hereinafter be described in greater detail. It will be apparent that I have been thus enabled to control the phonograph mechanism directly from the record and irrespective of either the diameter or thickness or configuration of the grooves of the record.

One object of my invention is to provide a control means which is adapted to co-operate with any type of record placed upon the turntable mandrel or other record support.

Another object of my invention is to provide such a controlmeans which can co-operate in different manners selectively with diflerent types of records placed upon the turntable.

Another object of my invention is to provide such a control means which is independent of the diameter or thickness, or other general physical characteristics, of the record.

Another object of my invention is to provide such a control means which is normally not actuated by an ordinary record, but which is actuated in a predetermined manner by any record 5 other than the present commercial records.

Another object of my invention is to provide a combination of control means on the record spindle which may be operated either simultaneously or selectively according to the type of rec- 5o ord employed.

Another object of my invention is to provide means for automatically changing the magnetic. pick-ups to accommodate the specific type of record employed. 56

Another object of my invention is to provide means for changing the weight applied to the magnetic pick-ups according to the type of record employed.

Another object of my invention is to provide a novel type of record spindle which is adapted to selectively close predetermined contacts.

Another object of my invention is to provide means to prevent new types of records from being injured by incorrect methods of playing (e. g., by the use of an unsuitable pick-up) on either existing or new types of phonographs.

Other and ancillary objects of my invention will be apparent to those skilled in the art from a reading of the following specification and from an inspection of the accompanying drawings in which:

Figure 1 is a diagrammatic showing of my improved control means and an illustrative system of controls actuated thereby.

Figure 2 is a sectional view through the center of a'turntable showing a formoimy invention having one general control unit and four selective controls.

Figure 3 is a top view of the spindle of Fig. 2.

Figure 4 is a top view of a record spindle of Fig. 1.

Figures 5 and 6 are top views of modified forms of record spindles.

Figure '7 shows the manner in which a record would cooperate with the spindle of Fig. 6.

Figure 8 shows the manner in which a record would cooperate with three of the five control means of Figs. 2 and 3.

Fig. 9 is a diagrammatic illustration of a control circuit actuated only on simultaneous energization of two or more other circuits.

Fig. 10 shows a turret arrangement of pickups.

Fig. 11 shows one form of magnetic control of the tone arm weight.

Fig. 12 shows another variety of magnetic control of the tone arm weight.

The disclosure of the said Figs. 9 to 12 is sufflciently clear to make a detailed description unnecessary.

Referring first to Fig. 1, III indicates a turntable of usual form and construction which is made integral with the sleeve II and the worm wheel I 2. This mechanism is supported upon the member l3, and the worm wheel I2 is driven through the worm l4 by the motor l5.

In the present illustration, the motor I5 is shown as of the series direct current type for convenience in illustration, but it will be apparent that this motor may be of any suitable type or design. The tone arm 20 is shown in displaced relation to the turntable III for convenience in illustration and carries the two magnetic pickups 2| and 22, the operation of which will be hereinafter described in detail.

' The turntable I is provided with a central spindle l (Fig. 4) which co-operates with ordinary records in the customary manner' to maintain them centered upon the turntable- This member l6 however differs from those usually provided in that it is provided with a vertically movable segment which actuates the rod I8, thereby completing an electrical circuit through the contact member l9.

In order to accomplish vertical movement of the segment I1, I provide the central holeof the record with a radial projection of any convenient or appropriate shape to co-operate with this segment II. It will be apparent that when such a record is placed upon the turntable II, the turntable must be rotated until the projecting portion of the record comes into co-operative relation with the segment i1, whereupon the segment will be pressed down as the record slides over the spindle I6, thereby closing the contact between the members I! and I9.

In series with the members l8 and it, there is connected 9. battery 30 or other equivalent source of power for energizing the magnet 2| of the multicontact relay 22. The same source of power also serves to energize the solenoid 23 in the tone arm 20. It will be apparent that alternating current may be used instead of direct current if a proper form of relay is provided.

When the segment IIis not depressed, the relay 32 normally lies in the righthand position, thereby closing the circuit between the contacts 40 and 4|, 42 and 43, 44 and 45, 46 and 41, 42 and 49, and 50 and SI under which condition the following effects are produced:

The closing of the circuit through the contacts 40 and 4| energizes the solenoid 22, thereby raising the magnetic pick-up 22 and lowering the pick-up 2|. The extent of this movement is such that when the needle of the pick-up 2| is in contact with the surface of the record, the forward end of the tone arm 20 is lifted slightly and the rear end thereof is depressed until clear of the stop nut 24. The pick-up 2| therefore has imposed upon it the additional weight of the arm 20 and of the pick-up 22 providing a double weight of the ,order of six ounces which is required for reproducing ordinary records. It will be obvious that the tone arm 20 may be provided with appropriate weights or counterweights to secure exactly the pressure required upon the pick-up needle.

The closing of the circuit through

contacts

42, 43 short-circuits the resistor 60 and thereby causes the full voltage of the source 30 to be applied ,to the motor l5 causing it to run at its maximum speed producing 78 R. P. M. of the turntable Hi. It will be apparent that if other types of motors are used, the specific form of electrical control must be modified to accommodate the particular type of motor, or any con trol mechanism known in the art for the control of the type of motor used, may be'provided. The

contacts

44 and 46 are .connected to the output circuit of the thermionic amplifier generally indicated at 6| which provides amplification of the impulses coming from the pick-ups 2| or 22, and when the

contacts

44 and 46 close the circuit through the

contacts

45 and 41, a filter circuit generally indicated at 62 is placed in series with the output, the circuit therefrom being completed through the

contacts

48 and 42, and i2 and II to the loudspeaker 82.

The purpose of this filter is to eliminate scratch noises and the like which are incidental to the ordinary types of records. As is well known,

these scratch frequencies fall within the acoustic range which is not recorded upon such records and, therefore, there is no loss in quality of sound reproduction by the use of such filter.

When a record of the type co-operating with the segment I! is placed upon the turntable,

and the circuit is thereby completed through the contacts I8 and I2, the relay 22 is moved to the left-hand position, thereby producing the following'changes in operation:

The opening of the circuit through the contacts 40 and 4| permits the reproducer 22 to fall and the reproduce: 2| to rise, thereby permitting the tone arm 20 to fall until it comes in contact with the stop nut 24. In this position, the reproducer 22 is pressed against the recordonly by the diiterence in weight resulting from the position of the pivot 25 and the weight of the core of the solenoid 22. It will be apparent that the pick-ups 2| and 22 can be so placed in relation to the pivot 25, and either or both may be so weighted as to produce any desired pressure of the pick-up 22 upon the record, this pressure, 01' course, being-much lighter than that produced by the pick-up 2|.

The opening of the circuit through the contacts 42- and 43 introduces the resistor 88 in the circuit of the motor l5 and in series there- 7 with, thereby reducing the speed of the motor to an appropriate amount as, for example, 33% R. P. M. or 50 R. P. M.

The opening of the circuits through the

contacts

44 and 45, 46 and 41, 48 and 48, and 50 and 5| removes the filter 82 from the circuit, the circuit from the amplifier 6| to the loudspeaker 62 being completed through the contacts 48 and 52, and 50 and 52. It will be apparent that the apparatus is then in condition to operate with a high fidelity type of record as (a) An appropriate pick-up is provided,

(b) Appropriate weight upon the pick-up is provided,

(0) The amplifier circuit is changed to one of a proper frequency characteristic, and

(d) The speed of the motor is reduced by an appropriate amount, and all of these things are accomplished directly through the co-operation of the record with the spindle l6 and the segment l1.

Different forms of spindle than that illustrated in Fig. 1 may be used to control these various features through, a single contact. For example, as shown in Fig. 5 a diametrical slide may be used as shown at 10 which may co-operate with either one projecting member on the inner surface of the spindle hole of the disc in either one of two positions 180 apart, or it may co-operate with a corresponding diametrical fin in the record hole. Alternatively, the portion I0 of the spindle may be fixed and the record be made to actuate either the segment 12 or the segment 13, or both.

The preferred form of spindle where only a single circuit is to be actuated thereby is shown in Fig. 6 wherein the fixed spindle is indicated at it and an annular sleeve surrounding itis indicated at IT. The external diameter of the sleeve I1 is such as to co-operate with the ordinary commercial records, while the special or high fidelity records are made with a hole corresponding to the external diameter of the spindle l6. It will be apparent that with this form of the device, not only is an unsymmetrical hole avoided, thereby avoiding increased expense of manufacture, but the record may be placed upon the spindle in any desired annular relation to the turntable thereby avoiding the necessity for rotating the record into appropriate position as is necessary in the form shown in Figs. 4 and 5.

The manner in which a high fidelity record 14 co-operates with the spindle l6 and with the sleeve I1 is shown in Fig. 7 where the sleeve is shown depressed by the record.

In the form of my invention shown in Figs. 2 and 3, 'I provide the spindle IS with an annular sleeve Il' as shown in Fig. 6 and further provide it with differently shaped segments I5, I6, 11 and 18. It will be apparent that any projection of the record which will correspond in shape with one or these segments'will not be co-operable with any other segment, and I am therefore able to provide a mechanism which in co-operatlon with a record having a central aperture of such diameter as to depress the sleeve l1' may be caused to selectively depress any one oi the segments 18. to 18 or all of them, or any combination of them.

As shown in F g. 2, this-form oi the invention, like that of Fig. 1, comprises the turntable I8 driven through a worm wheel l2 and a worm I 3. An ordinary record 804s illustrated as placed upon the turntable, being retained thereupon by the clamp member II. The circumferential sleeve I1 is fitted at its lower end with an appropriate bearing co-operating with the vertically movable but non-rotating contact member 82. When the sleeve I1 is depressed by the record, the contact 82 comes in contact with the stationary contact 82, thereby closing an electrical circuit and accomplishing, if desired, all the function shown and described in relation to Fig.

-1. The other contact members may be used for various purposes as, for example, to cause a further change in selection oi the magnetic pickup from laterally actuated to vertically actuated;

to introduce or remove various other filters from the amplifier circuit introducing dynamic amplificatio (that is, amplification in which the volume range or reproduction is not proportional to thevolume range of the matter being reproduced, or amplificationwherein the amplifiestion ratio is dependent upon the loudness of the sound being reproduced), etc., and these members operate similar contacts in a similar manher to the circumferential sleeve II. For example, the member actuates a sleeve 18' interiorly oi the sleeve 11' thereby moving a contact 84 into engagement with the contact 85;

the member]! moves a sleeve 15' within the sleeve 18', closing a circuit through the

contacts

86 and 81. Likewise, the sleeves 16' and 11' are moved by their corresponding

members

16 and 11 closing circuits through the contacts 88 and 88 and the contacts 90 and 9|. u

A lower bearing 92 may be provided for the purpose of steadying the lower end of the spindle.

Fig: 8 shows the manner in which a record 83 having special characteristics may co-operate with the spindle of Figs. 2 and 3. In this case the diameter of the central hole of the record is sufiiciently small to depress the sleeve I I. The

record is also provided with projections extending into the central hole and depressing the members I8 and I8, while the members 15 and 11 remain in their upper positions.

As pointed out above, when such a combination of control elements is used, they may be used in any grouping desired to selectively control circuits, etc. Further, there may be cross-connections as shown in Fig. 9 between the circuits of two of these control members connected to a relay in such a manner that if both of the control members are depressed, then a third circuit is closed which is not actuated by either. one alone, and similarly cross-connected relays can be arranged .to operate, and therefore become effective only when particular components of three control elements are used. .It will be ap-- parent that this arrangement provides a variety of control actuations and interconnections corresponding in versatility with the well known tintumbler cylinder blocks as the control members of my invention can be subdivided and multiplied to the same degree.

It will be apparent that my invention safeguards the record from any damage which might be caused by attempting to operate it in conjunction with an ordinary type of phonograph as the reduced diameter of the central hole or the provision of key members thereupon, or both, prevents the placing of the record upon an ordinary phonograph spindle.

My invention is not limited .to the use of the pivoted magnetic pick-ups illustrated as any other appropriate form of exchangeable mounting may be provided such, for example, as a turret type of head as shown in Fig. with either a step-by-step or selsyn type of control, and the weights or counterweights applied thereto may be individually and selectively controlled by separate magnets as shown in Fig. 11 or by the shifting of a movable weight along the turret as shown in Fig. 12.

The records used in the device of my invention may be provided with means on the soundtrack for control of the amplification as, for example, a sub-audible or super-audible frequency, and in such case, my control mechanism is used to connect the dynamic amplification control circuits to the amplifier and to the pick-up.

Having thus described my invention, I claim:

1. A phonograph spindle comprising a relatively fixed member and a relatively movable control member adapted to cooperate with said fixed member whereby both said members are adapted to threadedly receive a phonograph disc record having a standard central opening there! in, and said control member being adapted to be moved relatively to said fixed member under the influence of a phonograph disc record having a central opening of predetermined form.

2. A phonograph spindle comprising a relatively fixed member and an axially movable control member thereon adapted to cooperate with said fixed member whereby both said members are adapted to threadedly receive a phonograph disc record having a standard central opening therein, and said control member being adapted to be moved relatively to said fixed member under the influence of a phonograph disc record having a central opening of predetermined form.

3. A phonograph spindle comprising a relatively fixed member and a relatively movable control member slidable longitudinally thereof and adapted to cooperate with said fixed memher whereby both said members are adapted to threadedly receive a phonograph disc record havin a standard central opening therein, and said control member being adapted to be moved under the influence of a phonograph disc record having a central opening of predetermined form.

4. A phonograph spindle comprising an annular control element circumferentially thereof, and adapted .to co-operate with a phonograph-record having a hole of less diameter than the exterior of said control element and greater diameter than the inner portion of said spindle.

5. A phonograph spindle comprising a spindle body and an annular control element circumferentially thereof adapted to co-operate with a phonograph record having a hole of less diameter than the exterior of said control element and greater diameter than the body portion of said spindle.

6. Phonographic apparatus: comprising a turntable, an axial spindle, axially movable means upon said spindle adapted to co-operate with a predetermined portion of a phonograph record, and speed control means connected to said axially movable means i'or controlling the speed of rotation of the turntable.

7. A phonograph spindle comprising a relatively fixed component immovable along the axis of said spindle, and a plurality of components movable relative to said fixed component along said axis, said movable components being adapted to cooperate with said fixed component whereby all of said components coact to threadedly receive a phonograph disc record having a stand ard central opening therein, and said movable components being selectively movable relative to said fixed component by phonograph disc records having central openings therein of predetermined form.

8. A phonograph spindle comprising a relatively fixed component immovable along the axis of said spindle, a plurality of components movable relative to said fixed component along said axis, said movable components being adapted to cooperate with said fixed component whereby all of said components coact to threadedly receive a phonograph disc record having a standard central opening therein, and said movable components being selectively movable relative to said fixed component by phonograph disc records having central openings therein of predetermined form and sound reproducing means selectively controlled by said movable com-' ponents.

9. A phonograph record having the central hole and means projecting inwardly of said central hole for controlling the phonograph.

10. A phonographic apparatus including an output circuit and a record spindle provided with a relatively fixed component immovable on the axis of said spindle and a relatively movable component movable along said axis, said components cooperating with each other in a manner such that both said components are adapted to threadedly receive a phonograph disc record having a standard central opening therein, and said movable component being adapted to be moved relatively to said fixed component under the influence of a phonograph disc record having a central opening therein of predetermined form to control the connections of said circuit.

11. A phonographic apparatus including a drive motor and a spindle arranged to be driven by said motor and provided with a component movable along the axis of said spindle to control the connections of said motor.

12. In phonographic apparatus, the combination with a plurality of pick-ups, each adapted to cooperate with a phonograph record, of means for selectively bringing either of said pick-ups into cooperative relation with a record, aspindle provided with a component immovable on its axis, and a componentmovable longitudinally on said first named component for actuating said means.

13. A phonograph record provided with means adapted to co-operate with a special driving support and provided with means positively preventing its operation on a conventional driving support.

14. In combination, a phonograph turntable provided with means whereby it is adapted to type employing thermionic amplifying apparatus having predetermined characteristics, a turntable having an axial spindle, an electric motor cooperating with said spindle for rotating said turntable, said spindle comprising a relatively fixed member and a relatively movable membermovable longitudinally thereon, and saidmembers cooperating together whereby both said members are adapted to threadedly receive a phonograph disc record having a standard central opening therein, said relatively movable member beingadapted to be moved relatively to said fixed member under the influence of a phonograph disc record having a central opening of predetermined form, and means controlled by said relatively movable member when actuated by said last named record for changing the characteristics of said thermionic amplifying apparatus.

16. In phonographic apparatus of the type employing thermionic ampliiying means having certain predetermined characteristics, a tumtable having an axial spindle, an electric motor cooperating with the spindle for rotating the turn-table, means for controlling the speed of the electric motor,-means movably disposed upon said spindle, said means being arranged so as to cooperate with predetermined portions of a phonograph record, and means controlled by the axially movable means when displaced by the phonograph record for operating the electric movable means upon said spindle adapted to cooperate with predetermined portions of a phonograph record, and means controlled by the axially movable means when displaced by the phonograph record for controlling the lever operating means to determine which one of. the pick-up means is brought into operating posit-ion.

18. In electric phonographs of the type employing thermionic amplifying apparatus, a tumtable having an axial spindle, an electric motor cooperating with the "spindle for rotating the turn-table, a tone arm including at least one pick-up element, means for varying the effective weight of the tone arm, axially movable means disposed upon the spindle, said means being arranged so as to cooperate with predetermined portions of a phonograph record, and means controlled by said movable means when displaced by the phonograph record for operating the means for controlling the efiective weight of the tone arm, whereby the pressure between the pick-up means and the record may be varied.

19. In electric phonographs of the type employing thermionic amplifying apparatus including a loud speaker,- operable means to vary the characteristics of the amplifying apparatus, 'a tum-table provided with an axial spindle, an electric motor cooperating with the spindle for rotating the turn-table, operable means for varying the speed of the electric motor, a tone arm including a plurality of pick-up elements, an operating lever, said pick-up elements being mounted on said operating lever, said lever being mounted on the tone arm, and so arranged as to bring into operating position either of said. pickup elements, operable means for controlling the operation of said lever, means forming part of said spindle and adapted to cooperate with predetermined portions of a phonograph record, and arranged to be operated thereby, and means operative when-the last named means is displaced by a phonograph record for operating all of said operable means simultaneously.

ALFRED N. GOLDSMITH.