US3069075A - Punching machines - Google Patents

Description

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MAX E. SALLACH BEL/ Dec. 18, 1962 M. E. SALLACH PUNCHING MACHINES Filed Julie 14, 1961 15 Sheets-Sheet 15 N 8 W80 KEN 200 INVENTOR. MAX E. SALLACH United States Patent Ofiice 3,069,075 Patented Dec. 18, 1962 3,069,075 PUNCHING MACHINES Max E. Sallach, Chesterland, Ohio, assignor to Addressegraph-Multigraph Corporation, Cleveland, Ohio, a corporation of Delaware Filed June 14, 1961, Ser. No. 120,127 13 Claims. (Cl. 234-34) This invention relates to a new and improved control system for a data-controlled recordpunch, and more particularly to a new and improved translation and control system for controlling the operation of a punching apparatus to punch record cards, in accordance with a given code, with information corresponding to and representative of a code data that is pre-printed on the record cards in accordance with a parity code. This application is a continuation-in-part of application Serial No. 30,601, filed May 20, 1960, now abandoned.

In credit systems, and in similar record keeping systems, ,it is frequently desirable to record the initial data as rapidly as possible and in a form which permits subsequent conversion to a data code, or machine language that can be used by accounting machines, computers, and like business machines. In one business system of this kind, which is specifically intended to handle credit information, a record card is imprinted with the requisite data at the time of the credit transaction. The required information, which may include the serial number of the person receiving credit, the serial number of a branch business establishment, the amount of the transaction, and other pertinent data, is printed on a record card in coded form; it may also be printed in visually readable form at the same time. Preferably, the code employed is a relatively simple one and occupies a minimum of space, since at least some parts of the code data may necessarily be applied to a relatively small embossed printing device used as a credit card. Subsequently, it is necessary to convert the printed code data into a form which may be used with conventional accounting machines or like apparatus. In the specific example described hereinafter, the initial code data is ultimately converted to a conventional decimal code of the kind used in many accounting machines, although other forms of machine-usable code may also be employed. The present invention is directed to a translation and control system for the control of a reproducing punch which is effective to punch the pre-printed data in the record cards for subsequent use by accounting machines.

In a credit system, particularly where a large number of branch oflices or establishments are involved, as in the case of filling stations, there are several requirements which must be met in a control system of the kind with which the present invention is concerned. It goes without saying that the control of the reproducing punch must be quite accurate in order to preserve the basic integrity of the accounting information. This accuracy must also be maintained in situations where the pre-printed record cards may be accumulated over a period of time and may become smeared, marked, or otherwise defaced, Furthermore, the control system must maintain substantial accuracy even when the pre-printed data marks are displaced slightly from theirnormal reference positions on the record cards. Displacement of the data may be occasioned by variations in alignment of the'record cards in the printing machines employed to print the code data on the cards. The individual operators using these data printing machines may, in at least some instances, affect their operation by the manner in which they operate the machines. On the other hand, the requirement for accuracy of operation under adverse conditions is no more important than the requirement that the control system be susceptible of high speed operation. In many credit systems, the volume of data is quite substantial, to say the least, so that the speed at which the reproducing punch operates is a critical factor in determining the economic utility of the entire credit system.

It is an object of the present invention, therefore, to provide a new and improved control system for a punching apparatus which is effective to punch data in record cards, in accordance with a given data code and in response to information which is pre-printed on the cards in a substantially difierent code. Specifically, the printed data code comprises a two-element parity code, although other parity codes could be used.

A further object of the invention is to assure accurate and effective operation of a reproducing record card punch, actuated in accordance with code data that is preprinted on the cards being punched, despite the presence of extraneous marks on the cards.

Another object of the invention is to provide a continuous and effective check of the data being punched in a record cards, to make sure that all of the requisite data is punched and that no extraneous data is punched in the cards.

An additional object of the invention is to provide a new and improved control system for a reproducing punch utilized to punch accounting and similar data in record cards in accordance with code data pre-printed on the cards and to render that control system substantially independent of any requirement for precise positioning of the data in a reference area on each record card. That is, it is an object of the invention'to permit at least some variation in the positioning and alignment of the preprinted code data on the record cards without adversely aifecting operation of the punch control system.

An additional object of the invention is to provide a new and improved control system for a reproducing punch constructed to operate in accordance with a given code or machine language Without requiring that the control system itself be actuated by the same data code.

A particular object of the invention is to provide for high speed operation of a control system for a card punch actuated by pre-printed code data on the record cards being punched without entailing any sacrifice in accuracy of operation and without requiring undue precision or the absence of extraneous markings in the preparation of the record cards themselevs.

Another object of the invention is to provide a direct and accurate comparison of the setting of individual punch elements, in a control system for a card punch, with the original data supplied to the set-up apparatus that actuates the punch.

An additional object of the invention is to permit rapid and effective comparison of the total of all code data from a series of detail cards, in a card punch, with the corresponding data from a control or summary card, and to actuate the card punch to afford a positive indication of error if the comparison shows any difference.

A specific object of the invention is to provide a new and improved translation and control system, for a high speed card punch, that inherently and efiectively protects the integrity of the punched data with respect to additions to or omissions from the imput data supplied thereto.

Thus, the control system of the present invention is applied to a punching apparatus, operable in accordance with a given machine code, which is utilized to punch data in record cards in accordance with a given data code that is different from the machine code, the punched data corresponding to and being representative of data which are pre-printed on the cards in accordance with a parity code. A two-element parity code is preferred, but others can be used. In most instances, the parity code is substantially different from both the punched data code and the machine code. A control system constructed in accordance with the invention comprises means for feeding the pre-printed record cards in sequence through a scanning station to a punching station. The scanning station includes photoelectric sensing means which are employed to scan the pre-printed code data on each of the cards and to develop parity code signals representative of that data. The parity-code signals are applied to a parity checking circuit which develops a control signal indicative of the presence of extraneous marks or of the absence of any of the required code marks on each of the cards. The parity-code signals are also applied to a code translator or convertor which is coupled to the photo-electric scanning means; this code translator is employed to translate the parity-code signals into machine-code signals. The code translator, in turn, is coupled to a storage matrix which stores the machinecode signals. In addition, the control system includes actuation means, coupled to the storage matrix, which are effective to actuate the punching apparatus in accordance with the stored machine code signals upon advancement of each record card from the scanning station to the punching station. The parity checking circuit, on the other hand, may be employed to interrupt operation of the machine, to at least some extent, or to warn the machine operator when a discrepancy is detected with respect to the required pattern of parity code marks.

Other and futher objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof and what is now considered to be the best mode for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawings:

FIG. 1 is a perspective view of a punching apparatus in which a control system constructed according to the present invention may be incorporated;

FIG. 2 illustrates a record card containing pre-printed code data utilized by the control systems of the present invention, and also shows the same data in punched decimal-code form in the record card;

FIG. 3 is an illustrative diagram utilized to explain the machine code or language for the punching apparatus of FIG. 1;

FIG. 4 is a block diagram of a translation and control system constructed in accordance with one embodiment of the present invention;

FIG. 5 is a detail schematc diagram of a punch check circuit employed in the system shown in FIG. 4;

FIG. 6 is a schematic diagram showing, in deta l, a member of different circuits employed in the system of FIG. 4, including the sensing, amplification, code translation, and parity checking circuits;

FIG. 7 is a detail schematic diagram showing several stages of the data storage matrix and associated counter for the embodiment of FIG. 4;

FIG. 8 is a block diagram of a translation and control system constructed in accordance with a preferred embodiment of the present invention;

FIGS. 9A through 9] are explanatory figures used to illustrate the significance of symbolic circuit element representations used in succeeding drawings;

FIG. 10 is a logic circuit diagram showing the data sensing devices and certain code translation and error detection apparatus of the system of FIG. 8;

FIG. 11 is a logic circuit diagram of further error detection and control devices of the system of FIG. 8;

FIG. 12 illustrates a driver and storage circuit matrix incorporated in the system of FIG. 8;

FIG. 13 is a logic circuit diagram of a ring counter used to control the drivermatrix of FIG. 12;

FIG. 14 illustrates a translation, control, and accumulator circuit employed in the system of FIG. 8;

FIG. 15 is a logic diagram for an error detection circuit incorporated in the system of FIG. 8;

FIG. 16 illustrates a storage circuit employed to verify the setting of punch actuation elements under control of the system of FIG. 8;

FIG. 17 is a logic diagram showing several auxiliary control circuits incorporated in the system of FIG. 8; and

FIGS. 18 and 19 are detailed schematic diagrams of typical operating circuits that may be used in the system of FIGS. 817.

FIG. 1 illustrates a punch apparatus or mechanism 10 that is actuated under the control of a translation and control system according to the present invention. The machine 10 is used to punch data in record cards, in accordance with a conventional data code (in this instance a decimal code) and in response to code data previously printed upon the cards. The reproducing punch 10 comprises a first storage magazine 11 within which a quantity of pre-printed record cards are stored. From the storage magazine 11, the cards are individually fed to a conveyor or transfer mechanism generally indicated by reference numeral 12. The transfer mechanism 12 feeds the cards sequentially through a scanning station 13 to a punching station 14. The conveyor 12 also feeds the punched cards from the punching station 14 outwardly of the machine to a receiving hopper 15.

The mechanical aspects of the reproducing punch 10 are essentially similar to the punching machine described and claimed in Patent No. 2,710,406 to Walter T. Gollwitzer issued June 7, 1955. Accordingly, it is unnecessary to afford a detailed description or illustration of the mechanical operating elements of the punch. Briefly, pre-printed record cards are fed sequentially from the magazine 11 to the conveyor 12. Each record card, when it reaches the conveyor, is fed through the scanning station 13. In the scanning station, the pre-printed code markings on the card are sensed photoelectrically, as described in detail hereinafter. The code signals developed by the sensing apparatus at the station 13 are translated from the parity code used on the record cards into code signals corresponding to the machine code normally used to control the reproducing punch 10. The code signals developed by the sensing apparatus at the station 13 are translated from the party code used on the record cards into code signals corresponding tothe machine code normally used to control the reproducing punch 10. The code signals are stored, in a storage matrix described hereinafter, until the record card reaches the punching station 14. When the record card is in the desired position in the punching station 14, the stored data are employed to actuate the punch mechanism, which punches the record card in accordance with the same data that it carries in printed form. Thereafter, the card is removed from the punching station and deposited in the hopper 15.

In some instances it may be necessary or desirable to effect an auxiliary printing operation in the machine It). For this purpose, a printing station 16 may be incorporated in the reproducing punch 10, preferably intermediate the punching station 14 and the receiving hopper 15. Inasmuch as a suitable printing apparatus is described in complete detail in the aforementioned Gollwitzer patent, and since the control system of the present invention is not concerned with the printing operation, no further description of the printing station 16 is provided herein.

FIG. 2 illustrates a record card 21 which is pre-printed with accounting or other data in accordance with a parity code, in this instance a two-o'f-five code. The card 21 represents a preferred form of card employed in the control system of the present invention. In this regard, the actual size and shape of the card 21 are not particularly important, nor is the location of the pre-printed code data 22 on the card especially critical. However, the

than two marks.

code markings. employed for the data 22 are of some importance with respect to the operation of the control system and, accordingly, require description in detail. The illustrative code data 22 shows the individual markings employed for each of the numbers one through ten. In each instance, the numerical value is represented by two code marks, the actual numerical value being set forth immediately above the corresponding code markings. The code employed is a parity code; that is, there are no code designations which include more than two marks and there are no code designations which comprise less Starting from bottom to top, the five code levels or columns for the code data 22 correspond generally to the numerals 1, 2, 4 and 7, the top column being the parity column and being identified by the letter P. The same designations apply to the alignment of the photocells used to sense the data 22. The alignment of the photocells at the sensing station is shown at the lefthand side of FIG. 2, the photocells being designated by the reference characters 31, 32, 34, 37 and 40 respectively.

The card 21 is also punched with the same information as the pre-printed code data 22 in the form of punched data apertures 41. The punched data code, in this instance, is a conventional decimal code of the kind used by a wide variety of accounting machines. It will be recognized that the punched data 41 corresponds exactly to the pro-printed data 22. In addition, the punch unit 14 (FIG. 1) may include manually settable punch members for punching additional data in the card, as indicated in FIG. 2 by the further punched data 42. Furthermore, the reproducing punch may be provided with additional and independent control means for controlling the auxiliary punch data 42 if desired.

FIG. 3 illustrates the basic machine code or language employed to control operation of the reproducing punch in the aforementioned Gollwitzer patent. This data code, which is commonly used in connection with printing devices employed in addressing machines and the like, is substantially dilferent from the parity code used for the data 22 (FIG. 2). Consequently, it is not possible to control the reproducing apparatus 10 directly from the sensing of the data 22, and the translation and control system of the present invention provides for translation from the pre-printed code data 22 to the basic machine code illustrated in FIG. 3. Of course, it would be possible to use the code of FIG. 3 for the pre-printed data on the cards, but the control system for the present invention affords substantial advantages as compared with an arrangement of this kind. Moreover, it would also be possible to construct the reproducing punch 10 for direct actuation by the parity code shown in FIG. 2, but this would prevent the use of conventional coded printing devices in control of the reproducing punch.

FIG. 4 illustrates, in block diagram form, the basic control system of one embodiment of the present invention. The photocells 31, 32, 34, 37 and 4d are shown in FIG. 4 as a part of the control system 48; the order of alignment of the photocells is slightly difierent than in FIG. 2 in order that they may correspond to the circuit alignment described hereinafter in connection with FIG. 6. The photocell 31 is connected to a pre-amplifier circuit 51 which, in turn, is connected to an amplifier circuit 61, the output of the amplifier 61 being connected to a pulse voltage adder circuit 71. The photocell 32 is connected in circuit with a pre-amplifier 52 and an amplifier 62, the amplifier 62 having its output stage connected to the adder circuit 71. The circuit for the photocell 34 comprises a pre-amplifier 54 and an amplifier 64, whereas the circuit for the photocell 37 includes a pre-amplifier 57 and an amplifier 67. The operating circuit for the parity photocell 40 is essentially the same and includes a pro-amplifier 60 and an amplifier 70. The individual operating circuits for the photocells are carried through the adder circuit 71 to a translator 72 which is effective to translate the 124-7P parity code of the pro-printed data (FIG. 2)

to the 2-4-6-8-9 machine code required by the reproducing punch and illustrated in FIG. 3. The relative code values of the input and output circuits of the translator 72 are designated in FIG. 4 for convenience. The output or" the translator 72 is coupled to a storage matrix 73 which, in the illustrated arrangement, includes ten storage stages each having five individual storage levels corresponding to the five significant elements in the output code of the translator. The storage matrix 73 also includes the driving circuits for the reproducing punch, this portion of the control system being described in greater detail hereinafter in connection with FIG. 7.

The adder circuit 71 is coupled to a parity check circuit 74 which, in turn, is coupled to a ring counter 75. The ring counter 75 is utilized to control the timing of recording in the storage sections of the storage matrix 73. In addition, the ring counter 75 is coupled to a digit count check circuit or punch check circuit 76 which is utilized to make sure that each record card includes all of the necessary pre-printed code data, and no excess data, before a punch operation is effected.

In considering operation of the system illustrated in FIG. 2, it may first be assumed that the first column 24 of the pre-printed data 22 (FIG. 2) is moved into sensing position relative to the sensing photocells 31, 32, 34, 37 and 40. At this position, the photocells sense the presence of code markings in the first and parity columns; that is, the photocells 31 and 40 are effective to produce output signals indicating the presence of pertinent code markings. Since there are no code markings in the other three rows of the pro-printed data code column 24, similar signals are not generated by the photocells 32, 34 and 37. The two significant voltage signals are applied to the voltage adder circuit 71 which supplies to the parity check circuit 74 a signal that is representative of the sum of the two applied signals. The parity check circuit 74 is included in the system to make sure that two, and only two, marks are sensed. If this condition is maintained, the parity check circuit applies a pulse signal to the ring counter 75, actuating the counter to apply aconditioning signal to the first column in the storage matrix 73.

The two significant data code signals are also applied to the code translator 72, which translates these signals into the machine code (FIG. 3). In this instance, significant output signals from the translator would appear on the output lines designated as lines 2 and 9 in FIG. 4, since this is the equivalent to the coded numerical value one that appears in column 24 of the pre-printed code data 22 (FIG. 2). In this manner, by a joint action of the ring counter 75 and the translator 72, the number 7gne is recorded in the first stage of the storage matrix This process is repeated until all of the code data 22 are recorded, in translated form, in the storage matrix 73. When the recording operation is complete, the ring counter applies an output signal to the punch check circuit 76 which may be utilized to condition the reproducing punch for a punching operation. Conversely, if some portion or stage of the recording operation is not completed satisfactorily, and the ring counter does not count out, a punch operation is not eifected. In this manner the punch check circuit 76 prevents a punching operation except when the control system has determined that the desired number of data items, as represented by the full number of stages in the matrix 73, have been sensed, translated, and recorded in the storage matrix.

In some instances the printing machine or other means utilized to apply the pre-printed code data 22 to one or more record cards may fail to operate properly, or some other accident may occur which prevents accurate printing of one of the code designations. As a consequence, it may be that only one input signal is applied to the adder circuit 71, resulting in a low-amplitude output signal to the parity check circuit 74. When this happens, the parity check circuit 74 does not apply the requisite conditioning pulse to the ring counter 75. As a consequence, at the end of a sensing operation, the counter does not count out completely and a punch operation cannot be effected. Instead, the machine may be interrupted in operation or a warning signal may be actuated to let the operator know that a card has traversed the punching machine without being punched.

Similarly, in some instances additional code markings, smudges, or other undesirable markings may be interposed in the data code field of the card 21 (FIG. 2). If an extraneous marking of this kind is one to which the photocells are sensitive, and if the marking is positioned in alignment with one of the data columns, it may be that three or more of the photocells will develop significant output signals. In this event, the amplitude of the output signal from the adder circuit 71 to the parity check circuit 74 is also modified and again represents an erroneous operation. The parity check circuit 74, in this instance, again fails to apply the necessary actuating signal to the ring counter 7 and thus again prevents an erroneous punching operation.

FIG. 6 illustrates, in substantial detail, a number of the specific operating circuits incorporated in a preferred embodiment of the control system 48 shown in block form in FIG. 4. More specifically, the circuit shown in FIG. 6 includes the complete construction of the preamplifier 60 associated with the parity photocell 40, the amplifier 70, the adder circuit 71, the code translator 72, and the parity check circuit 74. In this figure, the amplifiers 61, 62, 64 and 67 are also shown; however, since these circuits are essentially similar to the amplifier 70, they are not illustrated in detail. For the same reason, it is deemed unnecessary to repeat the pre-amplifier and photocell circuits in FIG. 6.

In the specific circuit arrangement illustrated in FIG. 6, the photocell 40 is shown as a phototransistor. It should be understood, however, that this photocell may comprise a solid state photo-sensitive diode or any other suitable photoelectric sensing device if desired. Furthermore, other forms of radiation-sensitive pick-up may be employed, depending upon the nature of the code markings applied to the record cards. However, photoelectric pick-ups are preferred and particularly solid state devices because these are quite small in size, permitting condensation of the code data 22 (see FIG. 2) into a minimum size without adversely affecting the accuracy and response speed of the system.

The pre-amplifier 60, as shown in FIG. 6, may comprise two stages including a first transistor 101 and a second transistor 102. The base electrode of the firststage transistor 101 is connected to the collector electrode of the photocell 40, the emitter of the photocell being grounded. A suitable bias voltage is applied to the base electrode of the transistor 101, the biasing circuit comprising a resistor 103 connected from the base electrode to ground and a second resistor 104 connected to a negative D.C. supply. In this instance, the DC supply comprises a voltage divider including two resistors 105 and 114 connected in series with each other between ground and a suitable source of uni-directional operating potential herein designated as E.

The collector electrode of the transistor 101 is connected to the DC. supply source B through the voltage divider 165, 114. The emitter electrode in the first stage is returned to ground through a resistor 106 and is also coupled to the base electrode of the second transistor 102 through a coupling capacitor 107. The base electrode in the second stage of the pre-amplifier is returned to ground through an input resistor 108. The emitter electrode of the transistor 102 is returned to ground through a biasing circuit comprising a pair of resistors 109 and 111 which are connected in series with each other, the resistor 111 being by-passed by a capacitor 112.

The collector electrode of the second-stage transistor 1&2 in the pre-amplifier 60 is connected to the DC. supply source E- through a circuit comprising, in series, a resistor 113 and the voltage divider 105, 114. The output circuit for the pre-amplifier includes a coupling capacitor 115 which is connected to the collector of the transistor 102 and to a potentiometer 116, the other fixed terminal of the potentiometer being connected to the center terminal of a voltage divider comprising a pair of resistors 117 and 118 connected in series between the negative D.C. supply E- and ground. The variable tap 119 on the potentiometer 116 constitutes the output terminal for the pie-amplifier 60.

The amplifier 70 is a three stage amplifier comprising three vacuum triodes 121, 122 and 123. The output terminal 119 of the pre-amplifier is connected to the control electrode of the first triode 121. The cathode of the first stage triode is grounded. The anode is connected to a suitable source of positive-polarity unidirectional operating voltage 13+ through a circuit comprising, in series, a resistor 124 and a resistor 125. The resistor 125 is bypassed to ground by a capacitor 126.

The output circuit for the first stage triode 121 comprises a coupling capacitor 127 which is connected in series with a resistor 128 between the anode of the triode 121 and the control electrode of the second stage triode 122. The control electrode of the triode 122 is also returned to ground through a circuit comprising, in series, a diode 129 and a single-pole, single-throw switch 131. A positive bias is applied to the control electrode of the second stage in the amplifier 7t by a voltage divider circuit comprising two resistors 132 and 133 connected in series with each other between the B+ supply and ground, the common terminal of the two resistors being connected to the control electrode of the tube 122. The cathode of the second stage triode is grounded. The anode of this stage is connected to the B+ supply through a load resistor 134. The output circuit to the third stage comprises a coupling capacitor 135 which is connected between the anode of the triode 122 and the control electrode of the output stage 123. The control electrode of the third stage triode 123 is also returned to a negative supply voltage, herein designated as F-, through an input resistor 136.

The anode of the third stage triode 123 in the amplifier 70 is connected to the B+ supply through a resistor 137. This stage of the amplifier comprises a cathode follower. Thus, the output circuit comprises a pair of resistors 138 and 139 which are connected in series with each other between the cathode and ground, the output terminal being the common terminal of these two resistors as indicated by reference numeral 140. The output terminal 140 of the amplifier 70 is connected through a resistor 142 to the first stage of the parity check circuit 74, which is described in detail hereinafter. Similarly, the output terminals of the amplifiers 61, 62, 64 and 67 are connected through corresponding resistors 143, 144, 145 and 146, respectively, to the parity check circuit. Moreover, the output terminals of these amplifiers are individually returned to ground through the resistors 147, 148, 149 and 150. Thus, the resistors 142-146 comprise a voltage adder for the output signals from the amplifiers 61, 62, 64, 67 and 70 and thus constitute the adder circuit 71 (see FIG. 4).

The input stage of the parity check circuit 74 comprises a triode 151, the control electrode of this triode being connected to each of the resistors 142146 of the voltage adder circuit. The anode of the input triode 151 in the parity check circuit is connected to the 13+ supply through a resistor 152. The cathode is returned to ground through a resistor 153. Both the anode and cathode circuits of the triode 151 are utilized as output circuits, so that the triode functions both as a conventional amplifier and as a cathode follower.

The cathode follower output circuit for the triode 151 comprises a coupling capacitor 154 which is connected to the cathode of the tube, the coupling capacitor being connected through a resistor 155 to the movable tap on a potentiometer 156. One fixed terminal on the potentiometer is connected to the negative supply voltage E-, whereas the other fixed terminal .of the potentiometer is returned to ground. The coupling capacitor 154 is also connected to the control electrode of a triode 157 which is combined with a second triode 158 in a one-shot multivibrator circuit. Thus, the biasing circuit comprising the resistor 155 and the potentiometer 156 affords a negative bias on the control electrode of the multivibrator tube 157.

The multi-vibrator circuit comprising the triodes 157 and 158 is substantially conventional in construction. The cathodes of the two triodes are connected together and are returned to ground through a resistor 159. The anode of the triode 157 is connected to the 13+ supply through a load resistor 161, the anode of the triode 158 being connected to B+ through a resistor 162. The coupling circuit between the two triodes comprises a coupling capacitor 163 connected between the anode of the first triode of the control electrode of the second triode, the control electrode of the second triode being connected to the B+ supply through a resistor 164. The circuit parameters are such that the triode 157 is normally maintained nonconductive, the triode 158 normally being held conductive. When a positive-going pulse signal is applied to the triode 157, and when this pulse signal exceeds a given threshold amplitude, the tube 157 is driven conductive and the triode 158 is momentarily cut off. Upon completion of the applied pulse signal, the tube 158 is again 'driven to conduction and the tube 157 is cut off.

The anode output circuit for the input triode 151 of the parity check circuit 74 comprises a coupling capacitor 165 which is connected from the anode of the tube 151 to the control electrode of an amplifier triode 166. The control electrode of the triode 166 is also connected to a voltage divider comprising a pair of resistors 167 and 168, the resistors 167 and 168 being connected between the B+ supply and ground to afiord a positive bias for the control electrode. The cathode of the triode 166 is returned to ground and the anode of this tube is connected to the B+ supply through a load resistor 169.

The inverter or amplifier stage comprising the triode 166 is a coupled to a one-shot multi-vibrator circuit, comprising a pair of triodes 171 and 172, which is essentially similar to the multi-vibrator including the triodes 157 and 158 Thus, the anode of the triode 166 is coupled to the control electrode of the tube 171 by a coupling capacitor 173. The control electrode of the tube 171 is provided with a negative bias by means of a circuit comprising a resistor 174 connected from the control electrode to the movable tap on a potentiometer 175. The potentiometer 175 is connected between the E- supply and ground. As before, the cathodes of the two triodes 171 and 172 are connected to each other and are returned to ground through a resistor 176. The anodes of the triodes 171 and 172 are connected to the B+ supply through two resistors 177 and 178, respectively. The anode of the tube 171 is coupled to the control electrode of the triode 172 by a coupling capacitor 179. The control electrode of the tube 172 is connected to the B+ supply through a bias resistor 181. The circuit parameters are again selected to afford a one-shot operation as described hereinabove.

The one-shot multi-vibrator comprising the triodes 171 and 172 is coupled to an inverter amplifier stage comprising a triode 183. The coupling circuit comprises a coupling capacitor 184 that is connected between the anode of the tube 172 and the control electrode of the triode 183. The control electrode of the tube 183 is returned to ground through an input resistor 185. The cathode of the tube is grounded and the anode is connected to the B+ supply through a pair of resistors 186 and 187 that are connected in series with each other.

The final stage of the parity check circuit .74 comprises a triode 191 having an input circuit coupled to the inverter stage 183 and to the one-shot multi-vibrator 157, 158. The coupling circuit from the triode 183 comprises a capacitor 192 that is connected to the junction of the resistors 186 and 187 in the anode circuit of the triode. The capacitor 192 is also coupled to the control electrode of the tube 191 through an input resistor 193. A diode 194 is connected from th common terminal of the capacitor 192 and the resistor 193 to ground. The other coupling or input circuit to the tube 191 is similar, and comprises a capacitor 195 and a resistor 196 connected in series with each other between the anode of the multivibrator tube 157 and the control electrode of the output tube 191. A diode 197 is connected from the common terminal of the impedances 195 and 196 to ground.

The output tube'191 of the parity check circuit 74 is connected in a cathode follower circuit of quite simple configuration. Thus, the anode of the triode is connected to the B+ supply. The cathode of the tube, which in this instance is the output electrode, is returned to ground through a load resistor 198. The output terminal of the final stage in the parity check circuit is indicated by reference numeral 199, and this output terminal is connected to the ring counter 75, which is described detail hereinafter in connection with FIG. 7.

As noted hereinabove, each of the amplifiers 61, 62, 64, 67 and 70 is coupled to the code translator 72, in addition to the connection to the parity check circuit 74. In FIG. 6, the individual output circuits from the amplifiers to the code translator 72 are identified by the code designations of the amplifiers, these being the code designations 1, 2, 4, 7 and P relating back to the code designations for the data 22 (FIG. 2). The code translator 72 is provided with five output circuits comprising the output resistors 202, 204, 206, 208 and 209. These output resistors are individually connected to output coupling capacitors 212, 214, 216, 218 and 219, respectively. The output circuit from the code translator 72 which comprises the resistor 202 and the capacitor 212 is the output circuit for signals corresponding to the code designation 2 in the machine code illustrated in FIG. 3. Similarly, the capacitor 214 and the resistor 204 are the circuit elements which form the 4 code designation circuit under the machine code. The machine code designations are shown in association with the output circuits from the code translator 72 in FIG. 6.

Between the input and output circuits of the code translator, a resistor-diode matrix is provided which performs the necessary translation. The translator resistors are generally represented by the reference numeral 221, and the coupling diodes of the translator by the reference character 222. All of the coupling resistors in the trans lator are approximately equal in resistance, and the diodes 222 are also essentially identical with each other. Furthermore, the system shown in FIG. 6 for the code translator 72 requires that the resistors 221 be substantially larger than the ground-return resistors, such as the resistor 139, in the input circuits to the code translator. Furthermore, it is also necessary that the resistors 221 be substantially smaller than the output resistors 202, 204, 206, 208 and 209.

In considering the operation of the circuits illustrated in FIG. 6, it may first be noted that the phototransistor 40 is normally maintained conductive, since the photocell is ordinarily illuminated by light refiected from unprinted areas of the record card. When this normal condition is changed, as when a code marking is interposed in the illumination path for the photocell, the photocell is rendered non-conductive, producing a negative-going pulse signal on the base electrode of the translator 101 in the pre-amplifier 60. This negative-going pulse signal appears in the output circuit of the emitter follower stage comprising the transistor 101 and is A.C. coupled to the base electrode of the second stage transistor 102 in the pre-amplifier. The pulse signal is inverted in polarity

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