US3569741A

US3569741A - Control means for recording device

Info

Publication number: US3569741A
Application number: US727877*A
Authority: US
Inventors: James B Godwin; Fred C Bolick Jr
Original assignee: Lanier Electronic Laboratories Inc
Current assignee: Lanier Electronic Laboratories Inc
Priority date: 1968-03-09
Filing date: 1968-03-09
Publication date: 1971-03-09
Anticipated expiration: 1988-03-09

Abstract

A control means for controlling the operation of a recording device having a plurality of modes of operation in response to a plurality of control currents. The control means provides for control of the recording device from one or more operating stations and the control means includes a plurality of current means for providing a plurality of control currents in response to a plurality of potential differences between a plurality of first voltages provided by a circuit means and a variable second voltage provided by a selecting means. The variable second voltage is selectively varied at the recording device from an operating station with substantially no flow of current between the recording device and the operating station and with a minimum number of wires required between the recording device and the operating station. Thus, the control means is reliable because it is independent of fluctuations of current between a recording device and an operating station and is relatively inexpensive because of the small number of wires required between a recording device and an operating station.

Description

United States Patent [72] lnventors Fred C. Bolick, Jr.;

James B. Godwin, Atlanta, Ga.

[21] Appl. No. 727,877

[22] Filed Mar. 9, 1968 [45] Patented Mar. 9, 1971 [73] Assignee Lanier Electronic Laboratory Incorporated Atlanta, Ga.

[54] CONTROL MEANS FOR RECORDING DEVICE OTHER REFERENCES An electric Selector Switch Employing Transistors by Gerald B. l-lerzog RCA Technical Note 142 (Three Pages Recieved U.S. Patent Office 4/1958) Primary ExaminerDonald D. Forrer Assistant Examiner-Harold A. Dixson Attorney-Jones & Thomas ABSTRACT: A control means for controlling the operation of a recording device having a plurality of modes of operation in response to a plurality of control currents. The control means provides for control of the recording device from one or more operating stations and the control "means includes a plurality of current means for providing aplurality of control currents in response to a plurality of potential differences between a plurality of first voltages provided by a circuit means and a variable second voltage provided by a selecting means. The variable second voltage is selectively varied at the recording device from an operating station with substantially no flow of current between the recording device and the operating station and with a minimum number of wires required between the recording device and the operating station. Thus, the control means is reliable because it is independent of fluctuations I of current between a recording device and an operating station and is relatively inexpensive because of the small number of wires required between a recording device and an operating station.

PATENTED HAR 91971 BY James B. Godwin.

ATTORNEXS coNrnoi. MDANs son nnconnmo DEVICE BACKGROUND or THE INVENTION l Field of the invention This invention relates to recording devices for recording on a recording medium using a plurality of modes of operation and more particularly, to a control means for controlling the operation of a recording device from at least one operating station and which requires a minimum number of wires between the operating station and the recording device and substantially no flow of current between the operating station and the recording device.

2. Description of the Prior Art A recording device for recording material on a recording medium using a plurality of modes of operation of the record ing device which are controlled from an operating station is well known in the prior art. An essential requirement for such a prior art recording device is a control means for controlling the operation of the recording device from an operation station. However, the control means which has generally been used with a prior art recording device has caused a number of problems. i I

For example, the control means which has generally been used with a prior an recording device has customarily required a relatively large number of wires between the recording device and each operating station in order for the plurality of modes of operation of the recording device to be controlled from eaoh operating station. A relatively large number of wires between a recording device and each operating station not only makes the installation of a recording system including the recording device difiicult but also serves to increase the cost of the recording system in proportion to the number of wires required between the recording device and each operating station.

In addition, the control means which has generally been used with at art recording device has frequently required a relatively large current flow between the recording device and each operating station to provide control voltages or currents in the prior art recording device. An example of such a control means is that used with the recording device described in U.S. Pat. No. 2,820,852, issued on Jan. 21, 1958, to L. R. Jones et al. for a Dictation System and in this control means and in other control means requiring a relatively large current flow between the recording device and an operating station, the resistance of the wires between the recording device and the operating station and other factors .cause reductions or fluctuations in the current which make the operation of the recording device from an operating station unreliable.

SUMMARY OF THE INVENTION The invention disclosed herein is a control means for controlling the operation of a recording device which avoids the foregoing and other problems encountered in the prior art in that the invention is a control means which requires that only one or at the most two wires be used between the recording device and an operating station and which requires substantially no current flow between the recording device and an operating station. Specifically, the invention is a control means which includes a plurality of current means for providing a plurality of control currents that are within and restricted to the recording device and that are in response to a plurality of potential differences between a plurality of different first voltages and a plurality of different second voltages, circuit means for providing all of the plurality of different first voltages simultaneously to the plurality of current means so that the first voltage at each of the plurality of current means is different from the first voltage at others of the plurality of current means, and selecting means for providing the plurality of different second voltages sequentially to the plurality of current means so that the second voltage at each of the plurality of current means changes substantially simultaneously at all of the piurality of current means.

The changing of 'a second voltage at all of the plurality of current means while the plurality of different first -voltages are being simultaneously applied to all of the plurality of current means causes a plurality of potential differences at each of the plurality of current means to which each of the plurality of current means is selectively responsive. As a result, a plurality of control currents are provided by the plurality of current means in the recording device simply in response to changes in a second voltage. it is because the plurality of control currents provided by the invention are within and restricted to the recording device and because a second voltage is readily changed at a recording device from an operating station with a minimum number of wires and substantially no current flow between the recording device and the operating station that the invention provides a control means for controlling a recording device which requires only one or two wires between the recording device and an operating station.

In that embodiment of the invention disclosed herein, each of the plurality of current means includes a first potential responsive element and a second potential responsive element. The first potential responsive element is simply a first transistor having a first voltage applied to its emitter by the circuit means and a second voltage applied to its base by the selecting means. The second potential responsive element is simply a second transistor having the potential of the collector of the first transistor applied to its base and a substantially fixed predetermined control voltage across its emitter and collector.

Moreover, the circuitmeans and the selecting means are simply voltage dividei' circuits with the voltage division provided by the circuit means being substantially constant and with the voltage division provided by the selecting means being readily changed from an operating station. Thus, the in-' vention disclosed herein not only provides a control means for controlling a recording device with a minimum number of wires and substantially no current flow between the recording device and an operating station, but also a control means which is readily embodied in an embodiment that is relatively simple in construction so as to be relatively inexpensive to manufacture and easy to maintain.

DESCRIPTION OF THE DRAWING These and other features and advantages of the invention will be more clearly understood from the following detailed description and the accompanying drawing in which the FIGURE is a schematic presentation of an embodiment of the invention.

DESCRIPTION OF AN EMBODIMENT This FIGURE and the following detailed description disclose a specific embodiment of the invention. However, it will be understood that the invention may be embodied in other equivalent vention.

The invention disclosed herein may be most easily understood as a control means for controlling the operation of a recording device generally designated by the dashed line box 10 in the FIGURE. Usually, the recording device 10 is controlled from an operating station generally designated by the dashed line box 11 in the FIGURE.

Neither the recording device 10 nor the operating station ll is shown or described in detail since those skilled in the art will understand the general arrangement of a recording device 10 having a plurality of modes of operation such as recording, recording-reverse, and recording-review, and of an operating station ll having a plurality of switches which are manipulated to select the plurality of modes of operation. As a result, the FlGURE shows only the schematic presentation of a control means which is for controlling the operation of the recording device 10 and which embodies the invention disclosed herein.

forms without departing from the scope of the insecond voltage divider circuit 13 includes a resistor R6 selectively in series with a resistor R7, R8, R9, or R between the voltage V1 and ground G. The resistors R7, R3, R9, and R10 are located at the operating station 11 and the placing of these resistors R7, R8, R9, or R10 in series with the resistor R6 is described below.

In parallel between the first voltage divider circuit 12 and the second voltage divider circuit 13 are a plurality of

PNP junction transistors

14, 15, 16, and 17. The emitter E of the transistor 14 is connected to the first voltage divider circuit 12 between the resistor R1 and the resistor R2 and the emitter E of the transistor is cone connected to' the first voltage divider circuit 12 between the resistor R2 and the resistor R3. Similarly, the emitter E of the transistor 16 is connected to the first voltage divider circuit 12 between the resistor R3 and the resistor R4 and the emitter E of the transistor 17 is connected to the first voltage divider circuit 12 between the resistor R4 and the resistor R5.

The base B of each of the

transistors

14, 15, 16, and 17 is connected through one of a plurality of diodes D and a resistor R11, R12, R13, or R14 to the second voltage divider circuit 13 at a point P between the resistor R6 and the resistors R7, R8, R9 and R10 at the operating station 11. The collector C of the transistor 14 is connected through a resistor R15 to the base B of an NPN junction transistor 18 and the collector C of the transistor 15 is connected connected through a resistor R16 to the base B of an NPN junction transistor 19. Similarly, the collector C of the transistor 16 is connected through a resistor R17 to the base B of an NPN junction transistor and the collector C of the transistor 17 is connected through a resistor R18 to the base B of an NPN junction transistor 21.

The collector C of the transistor 18 is connected through a load L1 to a positive potential control voltage V2 and the emitter E of the transistor 18 is connected to ground G. The collector C of the transistor 19 is connected through a load L2 to the voltage V2 and the emitter E of the transistor 19 is connected to ground G. Similarly, the collector C of the transistor 20 is connected through a load L3 to the voltage V2 and the emitter E of the transistor 20 is connected to ground G. In addition, the collector C of the transistor 21 is connected through a load L4 to the voltage V2 and the emitter E of the transistor 21 is connected to ground G.

The loads L1, L2, L3 and L4 are representative of control elements within the recording device 10 which with the flow of a control current C1, C2, C3 an or C4 provide the various modes of operation of the recording device 10 in a manner which will be understood by those skilled in the art. A control current C1, C2, C3, or C4 occurs when a

transistor

18, 19, 20, or 21 fires and it will be understood that the amplitude of a control current C1, C2, C3, or C4 is independent of the plurality of first voltages provided by the first voltagedivider circuit 12 and the plurality of second voltages provided by the second voltage divider circuit 13. Moreover, it will be understood that is by the selective firing of the

transistors

18, 19, 20, and 21 that the control means provides for control of a recording device 10. This will better understood by considering the operation of the control means disclosed herein.

OPERATION In the operation of the control means disclosed herein, the first voltage divider circuit 12 serves as a circuit means for providing a plurality of different first voltages simultaneously to the emitters E of the

transistors

14, 15, 16, and 17 which serve as a plurality of first potential responsive elements. Similarly, the second voltage divider circuit 13 serves as a selecting means for selectively providing a plurality of different second voltages in sequence to the bases 13 of the

transistors

14, 15, 16 and 17.

In connection with the plurality of difierent first voltages applied to the

transistors

14, 15, 16, and 17 by the first voltage divider circuit 12, it will be understood that the voltage applied to the emitter E of the transistor 14 is less than the voltage V1 by the potential drop through the resistor R1, that the voltage applied to the emitter E of the transistor 15 is less than the voltage applied to the emitter E of the transistor 14 by the potential drop through the resistor R2, that the voltage applied to the emitter E of the transistor 16 is less than the voltage applied to the emitter E of the transistor 15 by the potential drop through the resistor R3, and that the voltage applied to the emitter E of the transistor 17 is less than the voltage applied to the emitter E of the transistor 16 by the potential drop through the resistor R4. Thus, the plurality of different first voltages simultaneously applied to the

transistors

14, 15, 16, and 17 by the first voltage divider circuit 12 are of progressively decreasing potential.

In that embodiment of the invention disclosed herein, the resistors R1, R2, R3, and R4 are of substantially equal value so that the potential of the plurality of i'ust voltages applied to the

transistors

14, 15, 16, and 17 is decreased in substantially equal steps from the transistor 14 to the transistor 17. Those skilled in the art will understand that each of the

transistors

14, 15, 16, and 17 will fire when the second voltage applied to its base B by the second voltage divider circuit 13 is sufficiently less than the particular first I voltage applied to its emitter E to provide required potential difference.

It will be understood from the description of the invention above that in applying a plurality of different second voltages to the

transistors

14, 15, 16 and 17, the second voltage divider circuit 13 selectively applies a plurality of different second voltages in sequence to the bases B of all the

transistors

14, 15, 16, and 17. Thus, whether a

transistor

14, 15, 16, or 17 fires depends upon which of the plurality of different first voltages is continuously applied to the

transistor

14, 15, 16, or 17 by the first voltage divider circuit 12 and upon which of the plurality of different second voltages is selectively applied to the

transistors

14, 15, 16, or 17 by the second voltage divider circuit 13.

In that embodiment of the invention disclosed herein, the resistors R11, R12, R13, and R14 are of substantially equal value and the the plurality of diodes D serve simply to prevent a

transistor

14, 15, 16, or 17 from being responsive to a potential applied to its base B which is greater than the potential applied to its emitter E. As a result, each of the plurality of second voltages which are selectively applied to the

transistors

14, 15, 16, and 17 by the second voltage divider circuit 13 is substantially the same at all of the

transistors

14, 15, 16, and 17.

From the foregoing, it will be understood that there is a potential of the point P which is such that the second voltage applied to the bases B of the

transistors

14, 15, 16, and 17 causes the transistor 14 to fire but not the

transistors

15, 16, and 17. Similarly, there is another and lower potential of the point P which is such that the second voltage applied to the bases B of the

transistors

14, 15, 16 and 17 causes the

transistors

14 and 15 to both fire but not the transistors 16 and 17. A further lowering of the potential of the point P causes a similar selective firing of the transistors 16 and 17. Thus, the firing of the

transistors

14, 15, 16 and 17 is dependent upon the potential of the point P and as the potential of the point P is progressively lowered, the

transistors

14, 15, 16, and 17 are progressively fired.

It is the plurality of resistors R7, R8, R9, and R10 at the operating station 11 which serve in the second voltage divider circuit 13 to progressively lower the potential of the point I. From the figure, it will be seen that a plurality of switches S1, 52,83 and S4 are provided at the operating station 11 and that upon the closing of the switch S1, the second voltage divider circuit 13 is completed to ground G from the voltage V1 through the resistance R6 and the resistance R7. The values of the resistors R6 and R7 are such that the potential of the point P applies a second voltage to the bases B of the

transistors

14, 15, 16, and 17 which is sufficiently less than the first voltage applied to the emitter E of the transistor 14 to provide a potential difference that tires the transistor 14 but which is not sufiiciently less than the first voltages applied to the emitters E of the transistors l5, l6, and E7 to provide a potential difference that fire any of the transistors l5, l6, and 17. Thus, the closing of a switch Sli causes the selective firing of only the transistor 14.

The opening of the switch S1 and the closing of the switch S2 replaces the resistor R7 with the resistor Rd so as to lower the potential of the point P. The value of the resistor R8 is selected in conventional manner so that the amount by which the potential of the point P is lowered upon closing of the switch S2 is sufficient to provide a second voltage at the bases B of the transistors l4, l5, l6, and 17 which is relatedto the first voltages being applied to the emitters E of the transistors M, l5, l6, and 17 so that the resulting potential differences fire the transistors id and i5 but not the transistors 16 and 17. Thus, the closing of the switch S2 causes the selective firing of the transistors 14 and T5.

The opening of the switch S2 and the closing of the switch S3 or the switch S4 replaces the resistor R8 in the second voltage divider circuit 13 with either the resistor R9 or the resistor Rlll. The valves of resistors R9 and R10 are selected in conventional manner so that the placing of the resistor R9 in the second voltage divider circuit 13 lowers the potential of the point P by an amount which is sufficient to provide potential differences at the transistors M, 15, 16, and 17 that fire the transistors l4, l5, and id but not the transistor 17. Similarly, the value of the resistor R10 is selected in conventional manner so that the placing of the resistor R10 in the second voltage divider circuit 13 lowers the potential of the point P by an amount which is sufficient to provide potential differences at the resistors M, l5, l6, and 17 that fire all of the resistors M, 15, 116, and 17. Thus, the closing of the switch S3 causes the selective firing of the

transistors

1d, 15, and 16 and the closing of the switch S4 causes the selective firing of the transistors M, 15, 16, and 17.

From the figure and the foregoing description of the invention, it will 'be understood that the firing ofa transistor 14, it? or l7 causes one of the plurality of

transistors

18, 19, 20, and 21 to tire. This is because the firing of a transistor l4, 15, id, or l7 causes the potential of its collector C and the voltage applied to the base B of a transistor l8, 19, 20, or 21 to be reduced. I

The resistors l5, 116, 1'7, and 18 are selected so that the voltage applied to the base B of a transistor l8, 19, 20, or 21 from the collector C of a transistor l4, l5, 16, or 17 when a transistor M, l5, 16, or 17 fires is appropriate to provide the potential difference necessary to fire a transistor l8, 19, 20, or 211. Thus, it will be understood that the operation of a switch Sll, S2, S3 or S4 to provide one of a plurality of different potentials at the point P serves to cause the selective firing of a transistor l8, 19, 29, or 21 and the flow of a control current C1, C2, C3 or C4 through a load Ll, L2, L3 or L4.

Accordingly, it will also be understood that-each of the transistors Ml, l5, l6 and 17 is paired with a second voltage responsive element such as a transistor l8, H9, 20, or 21 as indicated in the FIG. to provide one of a plurality of current means for providing a plurality of control currents C1, C2, C3, and Cd in response to the plurality of second voltages pro vided by the second voltage divider circuit 13. It is by providing the plurality of second voltages in response to the operation of the switches Sl, S2, S3 and S4 that the second voltage divider circuit 13 serves as a selecting means not only for selectively providing one of the plurality of second voltages but also for selecting a plurality of control currents Cl, C2, C3, and Cd and a mode of operation of the recording device it in connection with the control currentsCl, C2, C3, an C4,

it should be emphasized that although that embodiment of the' invention disclosed herein provides four control currents, the number of control currentsprovided by the invention is easily varied by varying the number of transistors l4, l5, l6, and t7 and the number of transistors id, 119, 20, and 21.

From the foregoing description of the operation of the control means disclosed herein, it will be seen that the control means is a control means for controlling the operation of a recording device 10 in which all of the control currents C1, C2, C3 and C4 are restricted to the recording device 10 and in which only a single wire for the second voltage divider circuit 13 is required between the recording device 10 and the operating station 11. However, it should be understood that the first voltage divider circuit 12 is generally extended from the recording device 10 to the operating station lll as indicated by dashed line 30 in the FIG. so a ground G at the recording station 10 and a ground G at'the operating station 11 are replaced by a common potential with only the addition of a second wire between the recording station 10 and the operating station 11. This provides for more reliable control of the potential of the point P and of other voltages in the control means while still providing a control means having only a minimum numberof wires between the recording device 10 and an operating stationll.

In addition, it should be understood that regardless of number of wires, the values selected for the resistors such as resistor R6 are sufficiently large for there to be substantially no current flow between the recording station 10 and an operating station 11. Moreover, it 'will also be understood by those skilled in the art that many variations may be made in the embodiments chosen for the purpose of illustrating the present invention without departing from the scope thereof as defined by the appended claims.

We claim:

1. In a control means for controlling from a remote operating station the operation of a recording device having a plurality of modes of operation in response to a plurality of control currents; circuit means for simultaneously providing at said recording device a plurality of first voltages which differ from each other in potential; selecting means for sequentially providing at said recording device a plurality of second voltages which differ from each other in potential, each of said plurality of second voltages having a potential which corresponds to the resistance of one of a plurality of resistors which are of different resistances and which are located at said remote operating station and each of said plurality of second voltages being in response to the operation of one of a plurality of switches which are located at said remote operating station and which are constructed and arranged to make said plurality of resistors selectively operative to provide said plurality of second voltages; and a plurality of current means for providing a plurality of control currents restricted to said recording device when operative, one of said current means being operatively responsive to a potential difference between another of said plurality of first voltages and another of said plurality of second voltages.

2. The control means of claim 1 in which each of said plurality of second voltages is of substantially the same potential at all of said plurality of current means.

3. The control means of claim 2 in which said circuit means applies said plurality of first voltages simultaneously to all of said plurality of current means.

4. The control means of claim 3 in which said selecting means applies one of said plurality of second voltages simultaneously to all of said plurality of current means.

5. The control means of claim 4 in which each of said plurality of control currents has an amplitude which is independent of the amplitudes of said plurality of first voltages and said plurality of second voltages.

6. The control means of claim 1 in which each of said plurality of current means includes a first potential responsive element for providing an output potential in response toa potential difference between one of said plurality of first voltages and one of said plurality of a second voltages, and a second potential responsive element for continuously providing one of said pluralitypf control currents in response to said output potential.

7. The control means of claim 1 in which said selecting means includes a second circuit means which selectively includes one of said plurality of resistors and one of said plurality of switches and which operatively connects said plurality of resistors to said recording device.

8. The control means of claim 1 in which each of said current means includes a first switching means for providing a voltage output in response to a potential difference and a second switching means for providing a control current in response to said voltage output.

9. The control means of claim 8 in which said said first switching means is a first transistor having a collector, an

emitter to which one of said plurality of first voltages is applied, and a base to which all of said plurality of second voltages are applied in sequence; and in which said second switching means is a second transistor having a base operatively connected to said collector of said first transistor.

10. The control means of claim 9 in which said circuit means includes a voltage divider circuit.

11. The control means of claim 10 in which said selecting means includes a voltage divider circuit which selectively includes said plurality of resistors.

Claims

6. The control means of claim 1 in which each of said plurality of current means includes a first potential responsive element for providing an output potential in response to a potential difference between one of said plurality of first voltages and one of said plurality of a second voltages, and a second potential responsive element for continuously providing one of said plurality of control currents in response to said output potential.

9. The control means of claim 8 in which said said first switching means is a first transistor having a collector, an emitter to which one of said plurality of first voltages is applied, anD a base to which all of said plurality of second voltages are applied in sequence; and in which said second switching means is a second transistor having a base operatively connected to said collector of said first transistor.