Keyboard detector

Claim 2

A detector circuit for detecting the simultaneous depression of more than one key on a keyboard, comprising: a plurality of individually operable keys on said keyboard; a plurality of magnetic cores operatively associated with said keys; a first set of electrical conductors threading said cores in combinations according to a first digital code; a second set of electrical conductors threading said cores in a sense different from the threading of said first set of electrical conductors, according to a second digital code different from said first digital code; and means responsive to depression of any one key for causing said magnetic cores to develop a first digital code signal in said first set of conductors and a second digital code signal in said second set of conductors identifying said one key depression, means for utilizing at least one of said first and second code signals, means responsive to depression of a second key while said first key is effectively depressed for modifying at least one of said first and second digital code signals, and means for inhibiting said utilization of said signals in response to said modified set of signals.

Claim 3

Apparatus according to claim 1 further comprising further means responsive to release of the last to release of said keys for developing first digital code signals and second digital code signals identifying said last to release key, and means for utilizing at least one of said last named first and second digital code signals.

Claim 4

The invention defined in claim 2 and further comprising character gating means for receiving first digitally coded signals generated over said first set of electrical conductors, and means responsive to said developed first and second digital code signals corresponding to depression of a single key for issuing a strobe signal to said character gating means to advance said first digital code signals.

Claim 5

A control circuit for detecting the simultaneous depression of two or more keys on a keyboard, comprising: a plurality of individually operable keys on said keyboard; a plurality of magnetic cores operatively associated with said keys; a first set of electrical conductors threading said cores in combinations according to a digital code; a second set of electrical conductors threading said cores in a sense opposite to the threading of said first set of electrical conductors to provide the inverse of the digital code provided by said first set; and circuit means interconnected to said first and second sets of electrical conductors and operative in response to depression of a single key to develop code and inverse code signals, and operative in response to depression of more than one key to develop a code change in the signals of at least one of said sets of electrical conductors.

Claim 6

A control circuit for detecting the simultaneous depression of two or more keys on a keyboard, comprising: a plurality of individually operable keys on said keyboard; a plurality of magnetic cores operatively associated with said keys; a first set of electrical conductors threading said cores in combinations according to a digital code; a second set of electrical conductors threading said cores in a sense opposite to the threading of said first set of electrical conductors to provide the inverse of the digital code provided by said first set; and circuit means interconnected to said first and second sets of electrical conductors and operative in response to depression of a single key to develop code and inverse code signals, and operative in response to depression of more than one key to develop a code change in the signals of at least one of said sets of electrical conductors.

Claim 7

The invention defined in claim 4 wherein said circuit means includes a plurality of gating circuits equal in number to the number of sense lines in a set of electrical conductors.

Claim 8

The invention defined in claim 5 wherein said circuit means includes means for applying a code signal from a conductor of said first set and an associated inverse code signal from a conductor of said second set to an individual gating circuit, the output of said gating circuits being at a first level when a single key is depressed, and the output of at least one gating circuit being at a second level when at least two keys are depressed.

Claim 9

The invention defined in claim 5 and further comprising character-gating means for receiving the digital code signals generated by said first set of electrical conductors, and means intercoupled to said gating circuits and said character gating means and responsive to said developed signals for strobing said digital code signals when a single key is depressed and for inhibiting said digital code signals when at least two keys are depresSed.

Claim 10

A control system for detecting the simultaneous depression of two or more keys on a keyboard, comprising: a plurality of individually operable keys on said keyboard; a magnetic core for each key, each core having an air gap; means operable by each key to close an air gap and complete the magnetic circuit within the core adjacent the operated key when the key is operated; a first set of electrical conductors threading said cores in combinations according to a digital code; a second set of electrical conductors threading said cores in a sense opposite to said first set of electrical conductors to provide the inverse of the digital code provided by said first set of electrical conductors; means for simultaneously generating a magnetic field in said cores; and circuit means intercoupled to said first and said second sets of electrical conductors, and operative in response to depression of a single key to develop code and inverse code signals in respective ones of said sets of conductors, and operative in response to depression of more than one key to develop simultaneous code and inverse code signal changes in respective ones of said sets of conductors.

Claim 11

A control system for detecting the simultaneous depression of two or more keys on a keyboard, comprising: a plurality of individually operable keys on said keyboard; a magnetic core for each key, each core having an air gap; means operable by each key to close an air gap and complete the magnetic circuit within the core adjacent the operated key when the key is operated; a first set of electrical conductors threading said cores in combinations according to a digital code; a second set of electrical conductors threading said cores in a sense opposite to said first set of electrical conductors to provide the inverse of the digital code provided by said first set of electrical conductors; means for simultaneously generating a magnetic field in said cores; and circuit means intercoupled to said first and said second sets of electrical conductors, and operative in response to depression of a single key to develop code and inverse code signals in respective ones of said sets of conductors, and operative in response to depression of more than one key to develop simultaneous code and inverse code signal changes in respective ones of said sets of conductors.

Claim 12

A signal processing arrangement comprising a plurality of symbol keys on a keyboard, means for depressing said keys to establish a unique binary coded signal representative of the symbol associated with each of the depressed keys, means for translating an established binary coded signal only when one of said keys has been depressed, means responsive to more than one key being depressed to inhibit translation of any established binary coded signal associated with said depressed keys but responsive to the last-to-be-released key for translating the established binary coded signal associated with said last-named key.

Claim 13

A signal processing arrangement comprising a plurality of symbol keys on a keyboard, means for depressing said keys to establish a unique binary coded signal representative of the symbol associated with each of the depressed keys, means for translating an established binary coded signal only when one of said keys has been depressed, means responsive to more than one key being depressed to inhibit translation of any established binary coded signal associated with said depressed keys but responsive to the last-to-be-released key for translating the established binary coded signal associated with said last-named key.

Claim 14

A signal processing arrangement comprising a plurality of symbol keys on a keyboard, means for depressing said keys to establish a unique coded signal representative of the symbol associated with each of the depressed keys, means for translating an established coded signal only when one of said keys has been depressed, means responsive to more than one key being depressed to inhibit translation of any established coded signals associated with said depressed keys but responsive to the last-to-be-released key for translating the established coded signal associated with said last-named key.

Claim 15

A signal processing arrangement comprising a plurality of symbol keys on a keyboard, means for depressing said keys to establish a unique coded signal representative of the symbol associated with each of the depressed keys, means for translating an established coded signal only when one of said keys has been depressed, means responsive to more than one key being depressed to inhibit translation of any established coded signals associated with said depressed keys but responsive to the last-to-be-released key for translating the established coded signal associated with said last-named key.

Claim 16

A signal processing arrangement for a printer of the type employing a plurality of individually operable symbol keys on a keyboard, a magnetic circuit associated with each key and normally in an unmodified state, means responsive to the operation of each key to modify its associated magnetic circuit to a modified state, means responsive to said magnetic circuits assuming a modified state associated with the simultaneous operation of more than a single key for disabling printout of the symbol associated with each key until only one key remains depressed, and means responsive to the last-to-be-released key for enabling the printout of the symbol associated with said last-named key.

Claim 17

A signal processing arrangement for a printer of the type employing a plurality of individually operable symbol keys on a keyboard, a magnetic circuit associated with each key and normally in an unmodified state, means responsive to the operation of each key to modify its associated magnetic circuit to a modified state, means responsive to said magnetic circuits assuming a modified state associated with the simultaneous operation of more than a single key for disabling printout of the symbol associated with each key until only one key remains depressed, and means responsive to the last-to-be-released key for enabling the printout of the symbol associated with said last-named key.

Claim 18

In combination, a plurality of individually operable symbol keys on a keyboard, a magnetic circuit associated with each key and normally in an unmodified state, means responsive to the operation of a key to modify its associated magnetic circuit to a modified state representative of the symbol associated with the operated key, means responsive to said magnetic circuits assuming a modified state associated with the simultaneous operation of more than a single key for disabling utilization of said modified state representation until all keys are released except one which last remains depressed, and means responsive to said magnetic circuits assuming a modified state associated with the symbol of said remaining key for enabling utilization of said last-named modified state representation.

Claim 19

In combination, a plurality of individually operable symbol keys on a keyboard, a magnetic circuit associated with each key and normally in an unmodified state, means responsive to the operation of a key to modify its associated magnetic circuit to a modified state representative of the symbol associated with the operated key, means responsive to said magnetic circuits assuming a modified state associated with the simultaneous operation of more than a single key for disabling utilization of said modified state representation until all keys are released except one which last remains depressed, and means responsive to said magnetic circuits assuming a modified state associated with the symbol of said remaining key for enabling utilization of said last-named modified state representation.

Claim 20

A signal processing arrangement for a printer of the type employing a plurality of individually operable Symbol keys on a keyboard, a plurality of magnetic circuits operatively associated with each key and normally in an unmodified state, a first set of electrical conductors coupled to said magnetic circuits in a manner to provide a binary coded signal representative of the symbol associated with a depressed key, a second set of electrical conductors coupled to said magnetic circuits in a manner to provide a second binary coded signal representative of a depressed key, said first and second signals having an inverted relationship in response to the depressing of a single key, means responsive to said first and second signals having said inverted relationship to enable printout of the symbol associated with the depressed key, means responsive to more than one key being simultaneously depressed to modify said first and second signals such that they have a noninverted relationship, means responsive to said noninverted relationship first and second signals for inhibiting printout of symbols associated with the simultaneously depressed keys, and means responsive to said first and second signals returning to said inverted relationship upon release of all by one of said keys to enable printout of the binary coded signals associated with said one of said keys.

Claim 21

A signal processing arrangement for a printer of the type employing a plurality of individually operable Symbol keys on a keyboard, a plurality of magnetic circuits operatively associated with each key and normally in an unmodified state, a first set of electrical conductors coupled to said magnetic circuits in a manner to provide a binary coded signal representative of the symbol associated with a depressed key, a second set of electrical conductors coupled to said magnetic circuits in a manner to provide a second binary coded signal representative of a depressed key, said first and second signals having an inverted relationship in response to the depressing of a single key, means responsive to said first and second signals having said inverted relationship to enable printout of the symbol associated with the depressed key, means responsive to more than one key being simultaneously depressed to modify said first and second signals such that they have a noninverted relationship, means responsive to said noninverted relationship first and second signals for inhibiting printout of symbols associated with the simultaneously depressed keys, and means responsive to said first and second signals returning to said inverted relationship upon release of all by one of said keys to enable printout of the binary coded signals associated with said one of said keys.

Claim 22

In combination, a plurality of individually operable symbol keys on a keyboard, a plurality of magnetic circuits operatively associated with each key and normally in an unmodified state, a first set of electrical conductors coupled to said magnetic circuits in a manner to provide a coded signal representative of the symbols associated with a depressed key, a second set of electrical conductors coupled to said magnetic circuits in a manner to provide a second binary coded signal representative of a depressed key, said first and second signals having a first relationship in response to the depressing of a single key, means responsive to said first and second signals having said first relationship to enable printout of the symbol associated with the depressed key, means responsive to more than one key being simultaneously depressed to modify said first and second signals such that they have a different relationship, means responsive to said different relationship first and second signals for inhibiting utilization of signals associated with the simultaneously depressed keys, and means responsive to said first and second signals returning to said first relationship upon release of all but one of said keys to enable utilization of the signals associated with said one of said keys.

Claim 23

In combination, a plurality of individually operable symbol keys on a keyboard, a plurality of magnetic circuits operatively associated with each key and normally in an unmodified state, a first set of electrical conductors coupled to said magnetic circuits in a manner to provide a coded signal representative of the symbols associated with a depressed key, a second set of electrical conductors coupled to said magnetic circuits in a manner to provide a second binary coded signal representative of a depressed key, said first and second signals having a first relationship in response to the depressing of a single key, means responsive to said first and second signals having said first relationship to enable printout of the symbol associated with the depressed key, means responsive to more than one key being simultaneously depressed to modify said first and second signals such that they have a different relationship, means responsive to said different relationship first and second signals for inhibiting utilization of signals associated with the simultaneously depressed keys, and means responsive to said first and second signals returning to said first relationship upon release of all but one of said keys to enable utilization of the signals associated with said one of said keys.

Claim 24

In combination, a plurality of individually operable symbol keys on a keyboard, signal means associated with each key and normally in an unmodified state, means responsive to the operation of a key to modify its associated signal means to a modified state representative of the symbol associated with the operated key, means responsive to said signal means assuming a modified state associated with the simultaneous operation of more than a single key for disabling utilization of the said modified state representation until all keys are released except the one which last remains depressed, and means responsive to said signal circuits assuming a modified state associated with the symbol of said one key for enabling utilization of the modified state representation corresponding to said one key remaining last depressed.

Claim 25

In combination, a plurality of individually operable symbol keys on a keyboard, signal means associated with each key and normally in an unmodified state, means responsive to the operation of a key to modify its associated signal means to a modified state representative of the symbol associated with the operated key, means responsive to said signal means assuming a modified state associated with the simultaneous operation of more than a single key for disabling utilization of the said modified state representation until all keys are released except the one which last remains depressed, and means responsive to said signal circuits assuming a modified state associated with the symbol of said one key for enabling utilization of the modified state representation corresponding to said one key remaining last depressed.