US2492135A - Potential matching electrical control system - Google Patents

Description

Patented Dec. 27,. 1949 UNIT-ED STATES PATENT OFFICE POTENTIAL MATCHING ELECTRICAL CONTROL SYSTEM Gerald Deak'in, New York, N. Y., assignor to International Standard Electric Corporation, New York, N. Y., a corporation of Delaware Application July 7, 1945-, Serial No. 603,640

11 Claims. 1

' This invention relates to electrical control systems in which a controlled device is actuated when a potential applied to the system at a control station is matched by a potential applied to the system at an operating station. It is particularly applicable to automatic telephone systems, but may be used in control systems and especially remote control systems of various types, such as electric elevator control, gun control, calculating machines, telegraph, ticket and other automatic printers and the like.

The two potentials, or potentials derived from them, are applied to an actuating device which acts on the controlled device when the potentials have a determined or matched relationship. In systems of this type the matching of the control station potential at the operating station is advantageously accomplished by a searching device which successively engages points of diiierent potential that may be above, below or the same as the potential selected at the control station. With this arrangement the relative polarity of the two potentials may be reversed as the searching device travels over said points.

A feature of the invention is the utilization, in a system of the indicated type, of an actuating device including an element that reacts differently when the relative polarity of two potentials applied to the element is changed, in combination with means for reversing connections between the element and the sources of the two potentials when the relative polarity between the potentials changes, so that the same relative polarity is maintained between the potentials actually applied to the element, regardless of changes in polarity of the potentials at their station sources. More specifically the invention includes the use of a vacuum tube as such element of the actuating system, the potentials being applied to the tube to control the potential relationship between the cathode and the control grid.

The tube is connected to actuate the controlled device such as a relay system when the required anode current is generated. Whenever the potential of the control grid of the tube is above the cut-off value the anode current will flow; and a feature of the invention is the provision of an automatic system that will maintain the control grid potential below the value at which the generated anode current will operate the actuated device, regardless of whether the potential at the operating station is above or below that at the control station, except when the potentials are matched. The potentials are considered to be matched when they either are the same or have 2 a potential difference of the proper polarity at which the required anode current will flow.

The invention isespecially advantageous when utilized in an automatic telecommunication system in which a register at the control station is provided with a brush moved over a series of contact points maintained at different potentials, .and a selector at the operating station is provided with a brush moved over a similar series of contact points. The purpose is to halt the selector brush on a contact point whose potential matches that of the point on which the register brush has been stopped. If the appropriate point is idle during the first passage of the selector brush the latter will be halted as soon as it reaches such point; but if the latter is busy its potential will be changed in a manner set forth in ,Deakin application hereinafter set forth, and the selector brush will continue to hunt.

Consequently this arrangement would ordinarily apply to the actuating device potentials both above and below the potential of the point selected at the register. However, since the invention includes the use of an actuating device in which the applied potentials maintain the same relative polarity, an automatic potential control system is employed which reverses the connections between the potentials at the stations and the actuating device whenever the relative polarity of such potentials is changed, thereby maintaining the same relative polarity between the potentials applied to the latter device.

This invention is a modification of the control circuits disclosed in the copending application of Gerald Deakin, Serial No. 484,184, filed April 23, 1943, and in the various applications and patents referred to therein; said application No. 484,184 having issued as Patent .No. 2,380,950 on August 7, 1945.

Other features and advantages of the invention will appear from the following description con- .sidered in connection with the accompanying drawin which is a diagram of as much of a control system as is necessary for a clear understanding of the present invention.

The drawing illustrates the application of the invention to an automatic telephone system in which calling and called subscribers stations I and 2 may be interconnected by means including a plurality of selector switches 3 and 4. The numerical operations of the selectors are con trolled by the calling subscribers customary impulse sender, key sender or other common form of control device through the agency of a register provided at the central exchange. The calling station l is connected to the brushes of selector 3 by Known switches (not shown) and a connecting circuit 0, and the register is attached to the connectlng circuit :2 through switching means 6.

The selector switches are of the customary type having a bank 01 terminals with which a set of brushes cooperates. 1n the drawings three brushes are snown i'or selector switch 3, the lowermost being designated as '1, although the selector may have a larger number 01 brushes. The selector brushes are moved over the selector terminals including test terminals ST while a magnet P is energized, and are stopped on a set or termlnals when this magnet becomes deenergized, this cons tructlon and operation being well known. The register comprises a series of switches successively operable by the calling device in accordance with successive digits of the called number which are dialed by the calling subscriber. Brush BR and a set of terminals RT of one of these register switches are illustrated. This is the register switch which responds to the digit in accordance with which the illustrated selector 3 is to be set. When brush RB is advanced toward one or its ten terminals in accordance with the operation oi the calling device at station I, the relay ARI having been energized in the customary manner, a circuit is closed from ground over the back armature and its front contact of relay ARI, the armature and back contact of register relay VR, the Winding of a ground relay GR, the winding of selector relay AR and the magnet P to grounded battery. A circuit is thereby closed from the battery through magnet P, relay AR, the armature and front contact of relay GR and resistor R5 to ground. Magnet P is energized and the brushes of selector switch 3 are driven over the selector terminals continuously in known manner until relay VB. is energized. The circuit of relay VR extends from the anode oi tube V through the front contact and front armature of relay ARI to the positive terminal of the high tension battery HTB, the negative of which is grounded.

Each of the register terminals RT is connected, preferably through a suitable resistor, to a source of potential, and in the illustrated arrangement these potentials are negative and increase progressively on successive terminals by four volt intervals. The selector terminals ST are similarly connected to corresponding negative potential sources. It will be understood that this particular potential arrangement, while advantageous, may be substantially varied within the scope .of the invention. The brush RB is connected through the winding of grid transfer relay GTR and rectifier S to the selector brush T. Brush RB is also connected through the winding of cathode transfer relay CTR to said rectifier.

The armature of the grid transfer relay GTR is connected to the control grid of the tube V and the armature of cathode transfer relay CTR is connected to the cathode of said tube. The front contact of relay GTR is connected to the back contact of relay CTR and to the selector brush T, while the front contact of relay CTR is connected to the back contact of relay GTR and to register brush RB.

With this arrangement current will flow through the relays GTR and CTR in parallel only when brush RB is positive with relation to brush T, since the rectifier S will prevent current flow through these relays when the brush T is more positive than brush RB. Consequently the control grid of tube V will be connected to brush RB when this brush is more negative, and to brush T when the latter is more negative and the relays and CTR are energized.

The characteristics or tube V are such that no cathode current suificient to energize relay VR will be generated when the control grid is negatively biased by the potential din'erence between the successive terminals in the register and selector, but will flow when the potential of the selected register terminal RT engaged by brush RE is the same as that of the selector terminal ST engaged by the brush T.

In the operation of this system, which will appear from the foregoing description, the selector brushes will start hunting when the relay ARI is energized, closing the circuit through the drive magnet P including a separate ground circuit, as well as the circuit through the magnet releasing relay VR between the tube anode and the high tension battery I-ITB. The selector brush T will apply varying potentials to the switching relay system, which will apply such potentials to the cathode of the tube V when they are more negative than the register brush RB, and to the control grid of the tube when they are more positive, the potentials from the latter brush being correspondingly switched between the control grid and the cathode, so that the tube is maintained below cut-oli and does not generate anode current until brush T contacts a terminal having the same potential as the terminal engaged by brush RB. When this occurs the anode current generated by tube V energizes relay VR, cutting out the circuit through magnet and halting selector brush T on the appropriate terminal. When relay ARI is deenergized, thereby deenergizing relay VR and closing the circuit through its armature to magnet P, the latter circuit will be opened by the back armature of relay ARI so that the magnet P will remain inactive even though the contacts of relay VR are closed.

It will be understood that the invention has been illustrated without complicating it by the If inclusion of other parts of the automatic telephone system in which it may be used, an embodiment of which is illustrated in the abovementioned Deakin application, Certain features which might be added to adapt the illustrated arrangement to particular uses, to produce particular types of operation or to adapt the circuit to tubes having different characteristics have likewise been omitted, since the use of such features under appropriate conditions will be apparent to those skilled in the art.

Moreover, while the illustrated embodiment is especially adapted for use in automatic telephone systems, and in particular the relay system actuated by the anode current of the tube is of a type suitable for use in such systems, it will be apparent that other types of controlled devices may be actuated by the anode current.

Moreover, different arrangements for selecting and applying the potentials to the two sides of 65 the switching system may be employed, though the disclosed arrangement has particular advantage when used with automatic telephone systems including a selector and register, or corresponding arrangements.

What is claimed is:

1. An electrical control system comprising actuating means responsive to a predetermined relationship in polarity and value between two applied potentials, means for providing a first 75 potential, means for providing a second potential varying between values above and below the value of the first potential, means for applying said first and second potentials to the actuating means, and means for automatically mechanically interchanging the applied potentials when the relative polarity of the first and second potentials changes to maintain the same relative polarity between the points of application of the potentials to the actuating means.

2. A system as set forth in claim 1 in which the actuating means includes a vacuum tube and the potentials are applied to the electrodes of the tube.

3. A system as set forth in claim 1 in which at least one potential providing means includes a plurality of contacts maintained at different potentials and an operating contact successively engaging said contacts.

4. A system as set forth in claim 1 in which the interchanging means includes a relay in series with a rectifier which operates when the relative polarity of the first and second potentials changes.

5. .An electrical control system comprising actuating means including a vacuum tube having a cathode, an anode and a control electrode, means for providing a first potential, means for providing a second potential capable of variation between values above and below the value of the first potential, means for applying to separate electrodes of the vacuum tube potentials corresponding to said first and second potentials, and means for automatically reversing the potential-applying connections to the electrodes when the relative polarity of the first and second potentials is reversed, including a control circuit connecting the potential providing means, a rectifier in the control circuit, and relay means in series with a rectifier in the control circuit, including reversing switch means actuated by the relay means operating on current flow in one direction only.

6. A system as set forth in claim 5 in which the relay means includes two relays having windings connected in parallel, armatures connected to the control grid and cathode respectively of the tube, each potential providing means being connected to the front contact of one relay and the back contact of the other relay for reversing the connections of the grid and cathode of the tube to the potential providing means when the relays are operated.

7. In a telecommunication system, a selector switch comprising a plurality of terminals connected to different potentials and an associated brush and means for moving the brush over the terminals, a register switch comprising a plurality of terminals connected to different potentials and an associated brush adapted to be set to a terminal representing a desired selection, means in the register including a vacuum tube and relays for applying the potentials from the brushes of the selector and register switches to different electrodes thereof, means for arresting the movement of the selector brush when the potentials applied to the electrodes of the tube have a predetermined relationship, and means in the control circuit controlled by said relays for reversing the connections between the brushes and the tube electrodes when the relative polarity of the two brushes is reversed.

8. An arrangement as set forth in claim 7 in which the connection reversing means includes a rectifier and relay means in series with the rectifier for reversing the electrode connections between the brushes and the electrodes operated by a change in relative polarity of the brushes, arranged to maintain the two electrodes at the same relative polarity.

9. An arrangement as set forth in claim 7 in which the relay means includes two relays having windings connected in parallel, armatures each connected to a different one of the electrodes, and front and back contacts, each front contact being connected to the back contact of the other rela and to a different brush, arranged to provide a reversing switch construction operative when the relays are energized and when they are deenergized to reverse the connections between the brushes and said electrodes.

10. Control means as set forth in claim 7, and means responsive to a polarity change for operating said relays for controlling the connection reversing means.

11. Control means as set forth in claim 7, and uni-directional means responsive to a polarity change for operating said relays for controlling the connection reversing means.

GERALD DEAKIN.

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

UNITED STATES PATENTS Number Name Date 1,855,380 Breyfogel Apr. 26, 1932 1,903,837 Richardson Apr. 18, 1933 2,237,413 Clark Apr. 8, 1941 2,242,776 Clark May 20, 1941 2,245,160 Schimpf June 10, 1941 2,354,682 Herbig Aug. 1, 1944 2,354,668 Deakin et al. Aug. 1, 1944 2,380,950 Deakin Aug. 7, 1945 FOREIGN PATENTS Number Country Date 393,359 Great Britain June 8, 1933

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