Typewriter carriage and ribbon field control for error correction

Claim 2

In a printing apparatus including character printing mechanism, paper support mechanism, spacing means for step-wise moving said paper support mechanism relative to said printing mechanism to accomplish printing of a line of characters, and backspace drive means for step-wise moving said paper support mechanism in a backward direction in letter-width increments upon successive operations of said backspace drive means, the improvement which comprises means for disabling said spacing means, a manually operable key operatively connected respectively to said backspace drive means and to said disabling means whereby actuation of said key will concurrently backspace said paper support mechanism and disable said spacing means to prevent movement of said paper support mechanism, and means actuated by said character printing mechanism for rendering said disabling means ineffective and said spacing means effective, said spacing means including an escapement and an impeller having a dog and the disabling means including a lever arranged to latch said escapement against movement, a slide member having spaced lugs sequentially engageable by said dog whereby to control the movement of said slide member, cam means associated with said slide member, and means actuated by said cam means to act on said lever to unlatch said escapement to render said spacing means effective.

Claim 3

A typewriter for use with a ribbon prOviding a printing field and a print obliterating field, said typewriter including character printing mechanism, paper support mechanism, spacing means for step-wise moving said paper support mechanism in a forward direction, to accomplish printing of a line of characters, printing control keys operatively connected to said character printing mechanism, a ribbon vibrator actuated by the printing control keys to bring a ribbon field momentarily into impressing position upon actuation of any one of said printing control keys, backspace drive means for step-wide moving said paper support mechanism in a backward direction in letter width increments upon successive operations of said backspace drive means, the improvement which comprises means for disabling said spacing means, and a manually operable key operatively connected respectively to said backspace drive means, said ribbon vibrator and said disabling means whereby actuation of said manually operable key will concurrently backspace said paper support mechanism, disable said spacing means to prevent movement of said paper support mechanism and condition said vibrator to move the obliterating field of said ribbon into position to obliterate an imprinted character upon actuation of a printing control key, said spacing means including an escapement and an impeller having a dog and the disabling means including a lever arranged to latch said escapement against movement, a slide member having spaced lugs sequentially engageable by said dog whereby to control the movement of said slide member, cam means associated with said slide member, and means actuated by said cam means to act on said lever to unlatch said escapement to render said spacing means effective.

Claim 4

A typewriter for use with a ribbon prOviding a printing field and a print obliterating field, said typewriter including character printing mechanism, paper support mechanism, spacing means for step-wise moving said paper support mechanism in a forward direction, to accomplish printing of a line of characters, printing control keys operatively connected to said character printing mechanism, a ribbon vibrator actuated by the printing control keys to bring a ribbon field momentarily into impressing position upon actuation of any one of said printing control keys, backspace drive means for step-wide moving said paper support mechanism in a backward direction in letter width increments upon successive operations of said backspace drive means, the improvement which comprises means for disabling said spacing means, and a manually operable key operatively connected respectively to said backspace drive means, said ribbon vibrator and said disabling means whereby actuation of said manually operable key will concurrently backspace said paper support mechanism, disable said spacing means to prevent movement of said paper support mechanism and condition said vibrator to move the obliterating field of said ribbon into position to obliterate an imprinted character upon actuation of a printing control key, said spacing means including an escapement and an impeller having a dog and the disabling means including a lever arranged to latch said escapement against movement, a slide member having spaced lugs sequentially engageable by said dog whereby to control the movement of said slide member, cam means associated with said slide member, and means actuated by said cam means to act on said lever to unlatch said escapement to render said spacing means effective.

Claim 5

In a printing apparatus including character printing mechanism, paper support mechanism, spacing means for step-wise moving said paper support mechanism relative to said printing mechanism to accomplish printing a line of characters, and means for disabling said spacing means, said spacing means including an escapement and an impeller having a dog, said disabling means including a lever arranged to latch said escapement against movement, a slide member having spaced lugs sequentially engageable by said dog whereby to control the movement of said slide member, cam means associated with said slide member, and means actuated by said cam means to act on said lever to unlatch said escapement to render said spacing means effective.

Claim 6

In a printing apparatus including character printing mechanism, paper support mechanism, spacing means for step-wise moving said paper support mechanism relative to said printing mechanism to accomplish printing a line of characters, and means for disabling said spacing means, said spacing means including an escapement and an impeller having a dog, said disabling means including a lever arranged to latch said escapement against movement, a slide member having spaced lugs sequentially engageable by said dog whereby to control the movement of said slide member, cam means associated with said slide member, and means actuated by said cam means to act on said lever to unlatch said escapement to render said spacing means effective.

Claim 7

In a printing apparatus including character printing mechanism, paper support mechanism, spacing means for step-wise moving said paper support mechanism to accomplish printing a line of characters, and means for disabling said spacing means, said spacing means including an escapement and an impeller having a dog, said disabling means including a lever arranged to latch said escapement against movement, a slide member comprising a plate having a cut out, a flat spring member received in said cut out, said plate and said spring member having spaced upstanding lugs arranged to be sequentially engageable by said dog whereby to control the movement of said slide member in one direction, said spring member being yieldable so as to permit the lugs thereon to pass under said dog in an opposite direction of movement of said slide member.

Claim 8

In a printing apparatus including character printing mechanism, paper support mechanism, spacing means for step-wise moving said paper support mechanism to accomplish printing a line of characters, and means for disabling said spacing means, said spacing means including an escapement and an impeller having a dog, said disabling means including a lever arranged to latch said escapement against movement, a slide member comprising a plate having a cut out, a flat spring member received in said cut out, said plate and said spring member having spaced upstanding lugs arranged to be sequentially engageable by said dog whereby to control the movement of said slide member in one direction, said spring member being yieldable so as to permit the lugs thereon to pass under said dog in an opposite direction of movement of said slide member.

Claim 9

In an error correcting typewriter comprising character printing mechanism including printing control keys operatively connected to said character printing mechanism, paper support mechanism, spacing means operatively controlled by said printing control keys for step-wise moving said paper support mechanism in a forward direction to accomplish printing of a line of characters, a ribbon providing a printing field and a print obliterating field, a ribbon vibrator actuated by the printing control keys guiding said ribbon to bring a ribbon field momentarily in impressing position, backspace drive means for stepwise moving said paper support mechanism in a backward direction in letter width increments, the imProvement which comprises means for disabling said spacing means to prevent forward movement of said paper support mechanism for two successive actuations of any of said printing control keys, a manually operable key connected with and operable to con-currently operate said backspace drive means, said disabling means and said ribbon vibrator to position the ribbon obliterating field in impressing position, whereby upon the actuation of a first printing control key next following the actuation of said manually operable key a character imprinted in error is obliterated, and means operated by said first printing control key for concurrently conditioning said spacing means and said ribbon vibrator for printing over the obliterated character a correct character upon the actuation of a second printing control key and for rendering said spacing means again effective.

Claim 10

In an error correcting typewriter comprising character printing mechanism including printing control keys operatively connected to said character printing mechanism, paper support mechanism, spacing means operatively controlled by said printing control keys for step-wise moving said paper support mechanism in a forward direction to accomplish printing of a line of characters, a ribbon providing a printing field and a print obliterating field, a ribbon vibrator actuated by the printing control keys guiding said ribbon to bring a ribbon field momentarily in impressing position, backspace drive means for stepwise moving said paper support mechanism in a backward direction in letter width increments, the imProvement which comprises means for disabling said spacing means to prevent forward movement of said paper support mechanism for two successive actuations of any of said printing control keys, a manually operable key connected with and operable to con-currently operate said backspace drive means, said disabling means and said ribbon vibrator to position the ribbon obliterating field in impressing position, whereby upon the actuation of a first printing control key next following the actuation of said manually operable key a character imprinted in error is obliterated, and means operated by said first printing control key for concurrently conditioning said spacing means and said ribbon vibrator for printing over the obliterated character a correct character upon the actuation of a second printing control key and for rendering said spacing means again effective.