US2298727A

US2298727A - Control system for phonographs

Info

Publication number: US2298727A
Application number: US370920A
Authority: US
Inventors: Corporation Dictaphone; Harold T Sherman
Original assignee: Individual
Current assignee: Dictaphone Corp
Priority date: 1940-12-20
Filing date: 1940-12-20
Publication date: 1942-10-13
Anticipated expiration: 1959-10-13

Description

Oct. 13, 1942. H. T. SHERMAN CONTROL SYSTEM FOR PHONOGRAPHS Filed Dec. 20,1940

-' TNR IENTOR Harold T IS/ierman BY I M%% MW? ATTOR Y5 Patented 13,

UNITED STATES PATENT. OFFICE v t r 2,298,727

coN'rnoL SYSTEM Foa rnoivooaarns Harold T. Los Angeles, Calif; asslgnor to Dictaphone Corporation, New, York, N. Y., a corporation of New York Application December 20, 1940, Serial No. 3703220 t Claims. (c1. ire-100.4)

This invention relates to lectric phonographs and more particularly to a simple remote control system for such phonographs.

Users of commercial phonographs ordictating machines frequently find it desirable to dictate as terconnected with the drive of the record-supporting mandrel l4, so :as to be moved transversely across the record It, when'the record is ro-.

, tated by motor l8, to cut a spiral sound record they move from place to place abouta room,

when recording is not actually being made. In

the past this has necessitated a special multiwire cable running from the machine to the microphone. Such a cable is not only expensive, but also inconvenient and cumbersome, and it limits the maximum distance by which the m1- crophone may be separated from the recorder.

In accordance with the present invention, the necessity for such a bulky multiple-wirecable is eliminated, and satisfactory remotely controlled operation is obtained by the use of a small cable containing a single shielded conductor. 1

It is, therefore, an object of this invention to provide asimple arrangementfor permitting control of an electric recording phonograph groove thereon when the recording head 22 is suitably energized. A microphone 24 and its associated circuit,

hereinafter to be described, is connected through suitable shielded cable 40, and a coupling condenser 56 to the input terminals 20 of asuitable audio-frequency amplifier 28, such, for example, as that shown in United States Patent 2,132,830. 'i'he output terminals 30 of amplifier 28 are connected by conductors 32 to the recorder head 22.

from a remotely positioned microphone, and one Operating potentials for the amplifier 28,;are obtained from a'suitable power supply, schematically indicated at 34, which may be any appropriate typev such as that disclosed in the lastmentioned patent. connected to any available source of power 36 such as the usual commercial power supply lines. The driving motor 18 is also connected, through conductors supply 36.

a An electric recording phonograph having the features as above described is well-known in the art and does not per se form any portion of the present invention.

In the past, in recording machines of this type, it has been customary to start and stop the actual recording process by starting and stopping the driving motor liby means of a switch inserted in the motor connections 38. For remote control of such a recording machine from a point described in the following specification and may be more readily understood by reference to the accompanying drawing which shows schematically the wiring diagram of electric phonograph apparatus embodying the present invention.

The electric phonograph chosen to illustrate the invention and schematically indicated at It in the drawing, may be'any suitable recording phonograph, such, for example, as one of those shownin the United States Patent 1,909,839.

Such a phonograph is provided with a base l2 rotatably mounting a record-supporting mandrel l4 carrying a recordit. The record-supporting mandrel I4 is driven by an electric motor I! through a pulley and belt drive 20. A suitable electro-mechanical translating device or recorder head22, such, for example,'as that shown in United States Patent 2,057,621, is supported on a traversable carriage mounting (not shown) innear the microphone 24, it was necessary to extend the motor connections 38 to a switch at thatpoint to control the operation of the motor. This necessitated another cable extending to the remote point in addition to the shielded cable 40 connecting the microphone 24 to the amplifier 28.

, In accordance with the present invention, such additional conductors are eliminated and the moto'r I8 is controlled from a switch on the body of the microphone 24 through the microphone cable 40. In the embodiment of the invention herein described, the microphone 24 is a carbon type microphone deriving its operating current from the power supply 34. This current flows from a terminal 42 on the power supply 34 through

conductors

44 and 46, th inner shielded conductor 38, to the power connected across the microphone 24 to improve and stabilize its operation. When the pushbutton 50 is depressed to close the microphone circuit, the microphone is connected across a source of electric potential, 1. e., terminals 54 and 42 of power supply 34, and a normal microphone operating current fiows therethrough. When sounds impinge upon microphone 24, a variable voltage is developed thereacross in the usual manner, and this voltage is impressed through a coupling condenser 58 across the input terminal 28 of the amplifier 28 which amplifies it and impresses it on recorder head 22.

In order to control the phonograph driving motor I 8 from the microphone 24, the winding 58 of a relay schematically indicated at 88, is interposed in the microphone circuit between

conductors

44 and 48, and the contacts 62 and 84 or the relay 80, normally held in open position by a spring 68, are connected in one of the leads 38 of the motor power supply circuit.

With this arrangement, when the dictator wishes to record on the recording machine In located some distance away, he picks up the microphone 24 and presses push-button 58. This not only energizes microphone 24 and impresses a voltage on the recording head 22 through amplifier 28, but likewise energizes solenoid 58 of relay 60 to close contacts 82 and 64 to complete the power supply circuit 38 of motor l8 thereby putting recorder ID in operation.

Thus, it is only necessary to run a simple single-wire shielded cable from the phonograph I and amplifier 28 to the remotely located microphone 24, that is, to merely use the normal necessary connection between the microphoneand the amplifier, to be able to remotely control the operation of the phonograph recorder unit I0.

As many embodiments may be made in the above invention and as many changes may be made in the embodiment above described, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative only and not in a limiting sense.

I claim:

1. In combination, an electric phonograph, a microphone located at a distance from said phonograph, two-conductor connection means extending from said microphone to said phonograph and forming the only electrical connection therebetween, control means at said phonograph for rendering operative certain elements thereof, means at said microphone for operatively connecting said microphone to said connection means, and means at said phonograph responsive to the operation of said last-named means for operating said control means. 1

2. In combination, an electric phonograph, a microphone located. remotely from said phonograph, a two-conductor circuit connecting said microphone to said phonograph, means located at said phonograph for controlling its operation, and remote control means for operating said phonograph control means comprising a switch mechanism located at said microphone for energizing said microphone by connecting it to said circuit, and a relay connected in said microphone circuit at said phonograph for operating said phonograph control means in response to energization of said microphone circuit.

3. In combination, an electric phonograph, a microphone remotely positioned with respectto said phonograph, two-conductor connection means forming the only electrical connection between said microphone and said phonograph. first control means located at said phonograph for rendering it operative, second control means located at said microphone and adapted to operatively connect said microphone through said connection means to said phonograph, and means located at said phonograph responsive to the operation oi said second control means for operating said first control means.

4. In combination, an electric phonograph including a record-supporting mandrel, a motor for driving said mandrel, an amplifier, and an electrical record unit connected to the output of said amplifier, a microphone remotely positioned with respect to said phonograph, a source oi. electrical power for energizing said microphone, a circuit connecting said microphone to said power supply and to the input of said amplifier, a switch connected in said circuit and located at said microphone for completing said circuit, a relay positioned at said phonograph, a solenoid of said relay being connected in said circuit with said microphone and adapted to be energized when said microphone is energized by closure of said switch, a source or electrical power for energizing said motor, and switching means operated by said relay to connect said motor to said motor power supply circuit whereby said motor is energized when said switch is closed to energize said microphone.

5. In combination, an electric recording machine, ,a microphone located at a distance from said machine, a source of electric power located at said machine for energizing said microphone, a'circuit connecting said source of power to said microphone, a switch located at said microphone for completing said circuit to energize said microphone, control means at said machine for rendering it operative, and means responsive to the energization of said microphone for operating said control means to put said recording machine in operation.

6. In combination, an electric recording machine including a record-supporting mandrel, a motor for driving said mandrel, an electronic amplifier, and an electrical recorder unit connected to the output of said amplifier, a carbon microphone remotely positioned with respect to said machine, a coupling condenser at said machine, a two-conductor microphone cable connecting said microphone through said coupling condenser to the input of said amplifier, a source of electric power at said machine for energizing said microphone, a relay positioned at said machine and having an energizing winding, a circuit at said machine connected to said two-conductor circuit on the other side of said coupling condenser from the input of said amplifier connecting said microphone in series with said power supply and the winding of said relay, a switch located at said microphone and connected in series therewith for completing the circuit through said microphone cable simultaneously to energize said microphone .and said relay and to complete the connection of said microphone to the input of said amplifier, a source of electric power for energizing said motor, and switching means operated by said relay to connect said motor to said motor power supply, whereby said motor is operated when said switch is closed to energize said microphone.

HAROLD T. SHERMAN.