US3614315A

US3614315A - Character repeat circuit

Info

Publication number: US3614315A
Application number: US756735A
Authority: US
Inventors: Charles A Glorioso
Original assignee: Teletype Corp
Current assignee: AT&T Teletype Corp
Priority date: 1968-08-26
Filing date: 1968-08-26
Publication date: 1971-10-19
Anticipated expiration: 1988-10-19

Abstract

A photoelectric keyboard employing a shutter which is cocked and released upon depression of a key has the information obtained from the shutter supplied to a storage register where it is held until a demand for it is made by a transmitting distributor. In order to repeat the information encoded by the depression of a particular key, the key is depressed farther than its normal lower position and blocks an auxiliary light channel, the output of which is detected by a photoelectric pickup device which inhibits the application of further inputs to the storage register. At the same time, a gated oscillator is triggered into operation to provide a series of reset pulses to a sample flipflop out of phase with but in synchronism with set or sample pulses applied to the flip-flop from a transmitting distributor. The ''''set'''' output of the flip-flop is used to sample the register output each time that the flip-flop is set from a reset condition.

Description

United States Patent OUTPUT TRANSMITTER DISTRIBUTOR SAMPLE PHOTO CELL 3,457,368 7/1969 Houcke 178/17 3,456,077 7/1969 Jones 178/17 3,225,884 12/1965 Krauss et al. 197/17 Primary Examiner-Kathleen H. Claffy Assistant ExaminerTom DAmico Attorneys-R. P. Miller and J. L. Landis ABSTRACT: A photoelectric keyboard employing a shutter which is cocked and released upon depression of a key has the information obtained from the shutter supplied to a storage register where it is held until a demand for it is made by a transmitting distributor. ln order to repeat the information encoded by the depression of a particular key, the key is depressed farther than its normal lower position and blocks an auxiliary light channel, the output of which is detected by a photoelectric pickup device which inhibits the application of further inputs to the storage register. At the same time, a gated oscillator is triggered into operation to provide a series of reset pulses to a sample flip-flop out of phase with but in synchronism with set or sample pulses applied to the flip-flop from a transmitting distributor. The set" output of the flip-flop is used to sample the register output each time that the flip-flop is set from a reset condition.

PULSE 33 PATENTEDUBI I9 I97l FIG. IA

FIG. IB

3 R O O 3 O 2 S fmm m T L R/ R AL Rm em 0 S T 0 3 3 B NA I l E VS W E H l L. 7 m 5 m 5 g I I H C R 8 W 0 l E 5M LR I III UE PN E v D D D D D W N N N N N L A A A A A A L OE b a In a .b a w m m m m m m 0 I 0 I O I III I m V 2 I I I l V III w 9 PF 0 I F L H A me D D D PC N N N A A A 3 3 B Ml f||J\l|I|||\ T 2 T U 2 MS P I T TO U 0 ATTORNEY CHARACTER REPEAT CIRCUIT BACKGROUND OF THE INVENTION In photoelectric keyboards of the type disclosed in the copending application Ser. No. 701,377 now US. Pat. No. 3,507,995 of Robert .I. Gianni and Dale A. Nonnemacher filed on J an. 29, 2968, using a shutter which is cocked and released upon depression of a key, the character is not stored mechani' cally but is supplied to a storage register from which it is ob tained on demand by a transmitting distributor. In the normal operation of the keyboard in order to repeat a particular character, it is necessary to repeatedly depress the key in order to recock and release the shutter to repeatedly restore the character and reset the readout circuit. This manner of repeating a character is inconvenient for situations in which a continuous repetition is desired, such as that used in underlining or in providing a sequence of dots to fill a particular portion of a line. As a consequence, it is desirable to provide a means for holding the information stored in the register for a predetermined period of time while allowing recycling of the readout circuit in order to effect repeating of particular characters when such repeating is desired.

SUMMARY OF THE INVENTION A repeat circuit for a keyboard in which normal operation of a key causes information represented by the key to be stored in a storage register including means responsive to depression of the key farther than required for a single operation thereof for inhibiting further inputs to the storage register while at the same time causing repeated sampling of the information in the register.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a block diagram of a preferred embodiment of the invention employed in conjunction with a keyboard encoding mechanism shown in partial side view;

FIG. 1A is a view of a portion of the keyboard encoding mechanism in which the component parts are shown in a position they occupy at a different stage of the operation of the keyboard mechanism;

FIG. 1B is a view similar to FIG. 1A showing the parts in the position that they occupy at a still different stage of the operation of the device.

DETAILED DESCRIPTION Referring now to FIG. 1, there is shown a circuit for providing a repeat function for use in conjunction with a photoelectric shutter keyboard of the type disclosed in the above-mentioned copending Gianni-Nonnemacher application. A portion of the keyboard mechanism disclosed in that application is shown in FIG. I, and the reference numerals applied to the parts of this keyboard mechanism are the same as those used in the Gianni-Nonnemacher application. Since a detailed description of the keyboard mechanism is given in that application, no such description will be given herein; but only the operation of that portion of the keyboard mechanism utilized in the repeat circuit operation, which is shown in FIG. 1, will be given.

In addition, in the following description, the terms positive" and negative are used to define the relative binary potentials used in the operation of the circuit. These terms are chosen merely for purposes of illustration, however, and are not to be considered limiting. As used herein, the words sample or sampling are intended to mean: to ascertain the nature or content of something by momentarily examining it, or that which is involved in such ascertaining.

The keyboard mechanism I is one of a plurality of similar keyboard mechanisms arranged in the manner disclosed in the above-identified application and is a photoelectric shutter keyboard, in which depression of a keytop 56 moves a key lever 55 downwardly to cause a permutation encoded shutter 106 to be tripped to momentarily block and then open selected ones of a plurality of light channels I10 and always to block and then open a universal hole 111. The manner in which the shutter is tripped is not important, but it should be noted that the shutter is cocked by rotating it about a pin I07 secured to a frame against the action of a spring 116 to cause the universal hole 111 always to be blocked by a universal hole blocking tab 113 mounted on the outer edge of the shutter 106. Light blocking tabs I12 are also mounted on the periphery of the shutter 106 selectively blocking different ones of the code bit generating holes IIO formed in the frame 80, different patterns of holes I10 being blocked for each different keyboard mechanism associated with each of the key levers 55.

When the shutter 106 is tripped, as described more fully in the above-mentioned Gianni-Nonnemacher application, the universal hole 111 is unblocked during a time when selected ones of the code bit generating holes 110 are fully blocked by the light blocking tabs 112. At the time that the universal hole 111 commences to change from a blocked to an unblocked condition through the release of the shutter 106, light from a light source I1 located in alignment with all of the universal holes 111 in the keyboard mechanisms is allowed again to strike a photocell pickup device I6 to reactivate that device to provide an output indicative of a change in condition of the universal hole 111 from a blocked to an unblocked condition.

This output transition obtained from the photoelectric pickup device 16 is applied to a pulse generator 16 which generates a positive pulse of a predetermined duration in response thereto. In the normal operation of the keyboard, the positive pulse obtained from the output of the pulse generator 17 is passed by an inhibit gate 18 and is applied directly to one input of a plurality of AND-

gates

14a and 14b, a different pair of

gates

14a and 14b being associated with a different level or code bit generating hole 110 corresponding to each of the bits of the permutation-coded output signals which can be obtained from a keyboard employing the keyboard mechanism I0 as the encoding device. The other inputs to each of the AND-

gates

14a and 14b are obtained from different photoelectric pickup devices (not shown) associated with each of the code bit generating holes 110 and provide a positive output on the corresponding data input terminals 13 whenever a hole 110 associated with the photoelectric pickup device for a given level is blocked, so that no light strikes the photoelectric pickup device for that level. Thus, those AND- gates 140, corresponding to levels of the input having blocked light channels 110, have a positive input applied thereto; and the AND-gates 14b, corresponding to levels of the input having unblocked light channels I10, continue to have a negative input applied thereto, since the inputs to those unselected gates 14b obtained from the input terminals 13 are negative for such unblocked light channels. The negative input signals on these unselected channels, however, are inverted by an inverter 15, providing a positive input to selected AND-gates 14b for each of those levels having a negative input signals applied to the input terminal 13.

Since the universal hole 111 is unblocked during the time that selected holes 110 are blocked, the positive pulse obtained from the output of the inhibit gate I8 and applied to the inputs of the AND-

gates

14a and 14b, causes a positive output pulse to be obtained from those AND-gates I4a for a level corresponding to a blocked channel 110 and from those gates 14b corresponding to a signal channel 110 which is unblocked at the time the output pulse from the pulse generator I7 occurs. The outputs of the AND-

gates

14a and 14b for each level of the input signal are applied to the set 1" and set 0" inputs, respectively, of a corresponding stage or level of a binary storage register 19, to cause each stage of the storage register 19 to store the permutation-coded input signal or character represented by the encoding of the light blocking tabs I12 on the particular shutter 106 which is tripped by operation of the selected key level 55. It should be noted that the permutationcoded character which is generated by operation of the keyboard mechanism may have any desired number of levels or bits, this number commonly being five or eight for most applications. In order to avoid unnecessary cluttering of the drawing, however, only three such levels of datainput and storage are shown in the drawing since all of the levels are identical.

The positive output pulse obtained from the inhibit gate 18 also is passed by an OR gate 20 to reset a sample flip-flop 21 to its state. This causes a negative signal to be obtained from the output of the flip-flop 21. Subsequently, a set 1 pulse is applied to the l trigger input of the sample flip-flop 21 from a suitable utilization device which may be a conventional transmitting distributor 22 used to distribute the data obtained from operation of the keyboard. This set 1 pulse is obtained from the transmitting distributor 22 each time that the transmitting distributor is ready to accept new data. When the flipflop 21 is set to its 1" state, a positive output pulse is obtained from its output and is applied to one input of a plurality of output AND-gates 23 and is passed by those AND-gates 23 which are enabled by corresponding stages of the storage register 19 which are set to their l state, since the other inputs to each of the AND-gates 23 are obtained from the l outputs of the stages of the storage register 19. Thus the output signals obtained from the AND-gates 23 are positive for those levels of the storage register storing a 1" therein and are negative for those levels of the storage register storing a 0 therein at the time the sample pulse is obtained from the output of the flip-flop 21. Thus, it may be seen that the permutation-coded outputs of the AND-gates 23 are the same as the permutation-coded input signals applied to the data input terminals 13 and stored in the different stages of the storage register 19. Operation of the same or another key lever 55 in the keyboard causes the above sequence of operation to be repeated.

The outputs of the gates23 are supplied to a suitable utilization device, such as the transmitting distributor 22; and these outputs are shown as being DC coupled; so that they are obtained only on the leading edge of the set 1 output pulse from the flip-flop 21. In some applications, DC coupling may be used; and the coupling shown is merely illustrative of one type of coupling which may be employed.

Referring now to FIG. 1A, there is shown a key lever 55 depressed to a position which is sufficient to disengage the shutter 106 from the key lever 55 causing it to be released to perform the operation described above. In this position, the downward movement of the key lever 55 is opposed solely by the spring 81 connected to the frame 80 by a rivot 82. It should be noted that in this position, a tab 120 is located just above a character repeat hole 121; so that light continues to pass through that hole. This light strikes a photocell pickup device 31 which provides a positive output whenever light impinges thereon. This positive output is inverted by an inverter 32 to a negative signal which is applied to the inhibit input of the inhibit gate 18, enabling that gate to pass the pulses from the pulse generator 17. The output of the inverter 32 also is applied to a gated oscillator 33, which is rendered inoperative by the application of a negative input signal thereto. Thus so long as the key lever 55 is depressed so that the extension thereon just touches a key lever return bar 61, the circuit provides a single output signal in response to depression of the key lever 55.

Referring now to FIG. IE, it is seen that movement of the key lever 55 from the position shown in FIG. 1A to the position shown in FIG. 1B is opposed both by the spring 81 and the key lever return bar 61 in the manner described more in detail in the above-mentioned Gianni-Nonnemacher application. The key lever 55 is depressed to the position shown in FIG. 1B

whenever it is desired to cause the character that was initiallygenerated by the key lever 55 to be generated repeatedly. In this position, the tab 120 blocks the repeat hole 121, so that no light impinges on the photocell pickup device 31 so long as the key lever 55 is held in this downmost position. When this occurs, the output of the photocell pickup device 31 is negative, which is inverted to a positive output potential by the inverter 32 and is applied to the inhibit input of the inhibit gate 18. This prevents any pulses generated by the sample pulse generator 17 from passing through the inhibit gate 18, and thus prevents the entry of any additional data from the keyboard into the storage register 19. it should be noted that the shutter mechanism 106 is tripped to initiate the entry and storage of the data represented by the key lever 55 just prior to the time that the repeat hole 121 is blocked, so that the data represented by the particular key lever 55 first is stored in the register 19 before the entry of additional data into the keyboard is prevented by blockage of the repeat hole 121.

The positive output potential obtained from-the inverter 32 is applied to the input of the gated oscillator 33 triggering that oscillator into operation to cause a sequence of pulses to be obtained from the oscillator 33 after a predetermined time interval. These pulses then are passed by the OR-gate 20, the output of which resets the sample flip-flop to its 0" state in the same manner discussed previously. The transmitting distributor 22 then sets the flip-flop 21 to cause output data to be read from the output AND-gates 23 in the same manner as described previously. Since the storage register 19, however, has not been reset by any new data, the output character which is obtained from the gates 23 continues to be the same output character which previously was obtained upon the application of the previous set pulse from the transmitting distributor 22 and applied to the flip-flop 21. The next output pulse obtained from the oscillator 33 following the setting of the flip-flop 21 causes the flip-flop 21 to be reset to its 0" state, whereupon the next pulse from the transmitting distributor 22 again initiates the reading of the output AND-gates 23, causing the character to be repeated. This sequence continues so long as the repeat hole 121 is blocked by the full depression of any key lever 55 in the keyboard.

Thus, once a particular character is stored in the storage register l9 and the key which tripped the shutter 106 causing the storage of that character is held fully depressed, no new data can be entered into the register 19 even though other key levers 55 may be depressed during the repeat cycle. The depression of any other keys when a key lever 55 is fully depressed blocking the repeat hole 121 causes the pulse generator 17 to provide an output sample pulse, but this pulse is blocked by the inhibit gate 18; so that the depression of these additional keys has no affect on the operation of the circuit during the repeat mode of operation. As soon as the key lever 55 is released, unblocking the hole 121, normal operation of the keyboard storage circuit resumes.

It should be noted that, although the invention has been disclosed in conjunction with a photoelectric keyboard, other types of keyboards may utilize the invention to supply the necessary input signals to the repeat circuit.

Although a particular embodiment of the invention is shown in the drawing and is described in the foregoing specification, other modifications of the invention, varied to fit particular operating conditions, will be apparent to those skilled in the art; and the invention is not to be considered limited to the embodiments chosen for purposes of disclosure, but it covers all changes and modifications which do not constitute departures from the true scope of the invention.

What is claimed is:

1. A system for providing the selective repeating of information obtained from a source of information including:

a storage device having an input and an output;

means for presenting information to the input of the storage device;

means for sampling the output of the storage device;

means responsive to a first event for rendering the information presenting means operative to cause the storage of said information in the storage device and for enabling the sampling means to sample the output of the storage device; and

means responsive to a second event for rendering nonoperative the .means responsive to said first event and for enabling the sampling means.

2. A system according to claim 1 wherein the means responsive to said first event enables the sampling means to provide a single sample of the output of the storage device and wherein the means responsive to said second event enables the sampling means to provide repeated samples of the output of the storage device.

3. A system according to claim 1 wherein the storage device is a binary storage register for holding information previously stored therein until the information presenting means causes the storage of new information therein.

4. A system according to claim 1 wherein said first event always precedes said second event.

5. In a device for providing the repeating of characters in a keyboard wherein movement of any key from a first position to a second position provides a first output indicative of the character represented by the key, and wherein movement of a key from the second position to a third position provides a second output indicative that the character represented by the key is to be repeated, the combination including:

means operated in response to said first output for storing a character; and

means operated in response to said second output for preventing operation of said storing means. 6. A device according to claim 5 further including means responsive to the storage of a character in the storing means for reading-out the character stored therein and wherein the means for preventing operation of the storing means enables the reading-out means to repeatedly readout the character stored in the storing means.

7. A system for providing the repeating of characters in a keyboard including:

a key", a storage register; means responsive to operation of the key for storing information corresponding to the key in the storage register;

means responsive to the storage of information in the register for sampling the output of the storage register following the storage of information therein; and

means responsive to movement of the key past a predetermined point for preventing the storage of additional information in the storage register by the means for storing information and further for causing the means responsive to the storage of information to repeatedly sample the output of the storage register.

8. A system according to claim 7 wherein the keyboard is a photoelectric keyboard having a shutter mechanism therein, so that operation of the key trips the shutter, providing an interruption of a light path detected by a photocell pickup device to provide input signals to the storage register in accordance with the encoding of the shutter.

9. A system according to claim 7 wherein the signal input obtained from depression of the key is a multilevel permutation-coded signal, wherein the storage register is a singlestage, multilevel binary storage register having a number of levels equal to the number of levels in said signal, and wherein the means for storing information in the storage register includes a plurality of coincidence gates corresponding to each of the storage registers, each gate having an input obtained from the keyboard, and further having a second input obtained from a pulse generator operated in response to operation of the key.

10. A system for providing the repeating of multilevel, permutation-coded signals generated in a keyboard including:

a key;

a single-stage, multilevel binary storage register having a number of levels equal to the number of levels in the signals;

a pulse generator operated in response to operation of the means responsive to operation of the key for storing a signal corresponding to the key in the storage register, including a plurality of coincidence gates corresponding to each of the storage re ister levels, each ate having an input obtamed from t e keyboard and urther having a second input obtained from the pulse generator; means responsive to the storing of information in the re gister for sampling the output of the storage register following the storing of information therein;

means responsive to movement of the key past a predetermined point for preventing the storing of additional information in the storage register by the means for storing information and further for causing the means responsive to the storing of information repeatedly to sample the output of the storage register; and

an inhibit gate wherein the output of the pulse generator is supplied through the inhibit gate to the second inputs of the coincidence gates and further wherein an inhibit input is supplied to the inhibit gate from the output of the means responsive to movement of the key past said predetermined point.

11. A system according to claim 7 wherein the sampling means is a bistable flip-flop which is set to a first condition by an output signal obtained in response to depression of the key and which is reset to a second condition, providing a sample pulse output, in response to a signal obtained from an output utilization device.

12. A system according to claim 11 wherein the means responsive to movement of the key past said predetermined point includes means for repeatedly setting the flip-flop to said first condition.

13. A system according to claim ll wherein the means for repeatedly setting the flip-flop includes a gated oscillator providing a sequence of output pulses to the flip-flop.

Claims

1. A system for providing the selective repeating of information obtained from a source of information including: a storage device having an input and an output; means for presenting information to the input of the storage device; means for sampling the output of the storage device; means responsive to a first event for rendering the information presenting means operative to cause the storage of said information in the storage device and for enabling the sampling means to sample the output of the storage device; and means responsive to a second event for rendering nonoperative the means responsive to said first event and for enabling the sampling means.

5. In a device for providing the repeating of characters in a keyboard wherein movement of any key from a first position to a second position provides a first output indicative of the character represented by the key, and wherein movement of a key from the second position to a third position provides a second output indicative that the character represented by the key is to be repeated, the combination including: means operated in response to said first output for storing a character; and means operated in response to said second output for preventing operation of said storing means.

6. A device according to claim 5 further including means responsive to the storage of a character in the storing means for reading-out the character sTored therein and wherein the means for preventing operation of the storing means enables the reading-out means to repeatedly readout the character stored in the storing means.

7. A system for providing the repeating of characters in a keyboard including: a key; a storage register; means responsive to operation of the key for storing information corresponding to the key in the storage register; means responsive to the storage of information in the register for sampling the output of the storage register following the storage of information therein; and means responsive to movement of the key past a predetermined point for preventing the storage of additional information in the storage register by the means for storing information and further for causing the means responsive to the storage of information to repeatedly sample the output of the storage register.

9. A system according to claim 7 wherein the signal input obtained from depression of the key is a multilevel permutation-coded signal, wherein the storage register is a single-stage, multilevel binary storage register having a number of levels equal to the number of levels in said signal, and wherein the means for storing information in the storage register includes a plurality of coincidence gates corresponding to each of the storage registers, each gate having an input obtained from the keyboard, and further having a second input obtained from a pulse generator operated in response to operation of the key.

10. A system for providing the repeating of multilevel, permutation-coded signals generated in a keyboard including: a key; a single-stage, multilevel binary storage register having a number of levels equal to the number of levels in the signals; a pulse generator operated in response to operation of the key; means responsive to operation of the key for storing a signal corresponding to the key in the storage register, including a plurality of coincidence gates corresponding to each of the storage register levels, each gate having an input obtained from the keyboard and further having a second input obtained from the pulse generator; means responsive to the storing of information in the register for sampling the output of the storage register following the storing of information therein; means responsive to movement of the key past a predetermined point for preventing the storing of additional information in the storage register by the means for storing information and further for causing the means responsive to the storing of information repeatedly to sample the output of the storage register; and an inhibit gate wherein the output of the pulse generator is supplied through the inhibit gate to the second inputs of the coincidence gates and further wherein an inhibit input is supplied to the inhibit gate from the output of the means responsive to movement of the key past said predetermined point.

13. A system according to claim 11 wherein the means for repeatedly setting the flip-flop includes a gated oscillator providing a sequence of output pulses to the flip-flop.