US1931656A - Control apparatus - Google Patents

Description

061:. 24, 1933. R, HATCH 1,931,656

CONTROL APPARATUS Filed Dec. 11, 192

1 l l l l l l l l l l INVENTOR ROBERT L HHT'CH BY c/ ATT NEY Patented Oct. 24, 1933 CONTROL APPARATUS Robert I. Hatch, Honolulu, Territory of Hawaii, assignor to Radio Corporation of America, a corporation of Delaware Application December 11, 1928 Serial No. 325,208

1 Claim.

In radio signalling and especially in short wave transmission it is often times desirable to control from a main station, a radio receiver or transmitter at a substation or auxiliary station which may be and often times is for various reasons located at a considerable distance from the main station.

One purpose of such an arrangement is to increase the signalling range and generally the substation is located in a position where signal transmission is favorable. Another purpose of such an arrangement is to improve the quality of the signals transmitted due to the favorable position of the substation.

In such arrangements signals are received at the remote station and relayed by conductors to the main station or relayed from the main station to the remote point to be retransmitted.

Heretofore operation of such an arrangement has been attended by many disadvantages such as the added expense of an operator at the remote station, loss of time in tuning the apparatus at the remote point and loss of signal strength due to variations in signal frequency or to drifting of apparatus at the remote point.

Another disadvantage common in the operation of such an arrangement is that the Wave band used at the transmitter or receiver cannot be readily shifted when it is desired to signal on a different frequency.

Briefly and broadly the object of this invention is to provide an arrangement by, means of which the receiver or transmitter at the remote point may be tuned within certain limits from one or more points at the main station.

A further object of this invention is to provide such an arrangement which utilizes the tone lines between the remote point and the main station to carry the energy necessary to accomat the remote point.

These objects are attained by the use of a small motor at the remote point the shaft of which is connected through reduction gearing r to the shaft of a tuning condenser in the plate filament or grid filament circuit of the transmitter or receiver used at the remote point. The field winding of this motor is energized by current taken from the receivers or transmitters plate potential source at the remote point. Current for the armature winding of the motor is provided by means of a pair of opposed parallel connected direct current generators at the main station adapted by means of a pair of contacts to be alternately connected in plish the tuning of the transmitter or receiver series with a lead connected to the midpoint of a repeater in the tone lines at the mainstation which tone lines are connected to one end of the armature winding of the control motor at the substation. The direction of flow of current in the armature winding is changed by opening or closing the pair of contacts one of which is connected to the positive side of one of the direct current generators while the other contact is connected to the negative side of the other of the direct current generators at the main station. The armature energizing circuit is completed by grounding the free end of each of the direct current generators at the main station and the free end of the motor armature winding at the substation. By closing one of the contacts one of the direct current generators at the main station is in series with the armaure winding of the control motor at the substation. This causes rotation of the shaft of the tuning condenser at the substation in a predetermined direction. By opening the first contact and closing the other contact the direction of the current through the armature of the motor at the substation will be reversed and the condenser will be rotated in the opposite direction. 1

The motor shaft at the substation is connected through a reduction gearing such as, for instance, a phonograph gear train which, in turn, is connected to a Vernier dial on the condenser shaft.

Means is provided at the remote station for connecting the armature of the control motor across a portion of the high potential battery of the receiver or transmitter so that preliminary adjustments of the condenser at the remote station may be made.

One advantage to be gained by the use of a device constructed in accordance with my invention lies in the fact that the tone lines in use between the main station and the substation can be utilized to carry the armature current thereby eliminating the .necessity to install other apparatus.

Another advantage to be gained by the use of my invention is that the control apparatus may be readily applied to stations now in operation without altering such stations in any manner.

,An added advantage to be gained by the use of a device constructed and arranged in accordance with my invention is that a plurality of control points may be provided at the main station in various convenient positions so that the tune of the transmitter or receiver at the substation may be accurately controlled without loss of time by the operator of the main statlon.

Various other objects and advantages will become apparent from the specification and therefrom when read in connection with the accompanying drawing in which the single figure shows the at present preferred form of my novel control apparatus.

Referring in particular to the drawing the tuning apparatus at the remote station which, in the drawing, is indicated at B on the right of the dotted line, comprises a direct current motor 1 the armature winding of which is connected at one end to the midpoint of the primary winding of a repeater coil 2 in the tone line the other end of the armature winding being grounded at 3. The field winding 4 of the motor 1 is connected through a resistance as, for instance, a lamp 5 to a point on the battery 6 which serves also as a high potential battery for the receiver or transmitter. The negative side of the battery 6 is grounded at '7. In order that the motor may be operated at the substation by energy from the plate battery a lead 8 is provided to connect the armature of the motor 1 in series through a resistance as, for instance, a lamp 9 and a contact point 10 with a portion of the battery 6. The shaft of the motor 1 is connected as indicated by the line 11 through a gear train 11' and Vernier dial, not shown, to the shaft of a tuning condenser 12 which is in series with a second variable condenser 13 which serves to regulate the net capacity of the unit which is connected by leads 14 to the tuning circuit not shown of the receiver or transmitter to be controlled.

At the control station at A on the left of the dotted line in the drawing a direct current generator 15 having its negative pole grounded is connected in series with a resistance as for instance a lamp 16 and a contact point 17 to a lead 18 connected to the midpoint of the secondary winding of a repeater coil in the tone line. A second direct current generator 19 having its positive pole grounded is connected or 21. When the contact 17 is closed current from the generator 15 flows through the lamp 16 contact 17, the tone lines and through the armature of the motor 1 at the substation. The field winding of the substation being energized by the plate battery causes the motor 1 to rotate in a predetermined direction thereby rotating the condenser and altering the tune of the tuning circuit of the transmitter or receiver. By opening the key 1'? and depressing the key 21 current is caused to flow in the opposite direction, causing the motor 1 to rotate the condenser in the opposite direction.

While, for purposes of illustration, I have shown but a single control point at the main station it is obvious that several such control devices may be installed at different appropriate points at the main station as, for instance, on all control tables and at the tone amplifiers. The resistances l6 and 20 will, where several such control points are provided, prevent damage in case all of the keys are depressed at thesame time.

In operation the signals are tuned byshort jabs on either a plus or minus button according to the requirements. The operator tunes the signal himself and can do this without interrupting his reception. After the apparatus at the substation has been adjusted it requires little attention, and can be controlled almost entirely from the main station.

Although for purposes of illustration I have fully shown and described the at present preferred form of my invention and the operation thereof it will be understood that I do not intend to limit myself thereby except as pointed out in the claim attached hereto.

I claim:

In apparatus for controlling from a remote point the position of a continuously rotatable shaft and for rotating the same the desired angular. amount in either direction, a plurality of potential sources having opposed terminals connected to ground at said remote point, a motor adjacent said shaft and connected thereto through reduction gearings, said motor having an armature winding, means at said remote point for connecting the armature winding of said motor in series with said sources of potential alternately whereby current may be caused to flow through said armature winding in the desired direction, a source of potential connected with the field winding of said motor, and means at said shaft for rotating the same including a circuit for connecting said armature winding in parallel with said field winding.

ROBERT I. HATCH.

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