Quiet repeat-line-indexing mechanism

Claim 2

In a typewriter having a frame, a carriage urged in an advance direction and being returnable, a platen, an operable platen-indexing device on the carriage, a power-rotated shaft means on the frame, a carriage return clutch, means connectable by said carriage return clutch with said shaft means consecutively to operate said platen-indexing device and to draw the carriage in return direction, a margin stop on the carriage for terminating carriage return movement and determining the left-hand margin position, a carriage-return-cushioning counterstop means on the frame normally operable thereon from a normal position a given distance to a final limit stop by said margin stop through return movement of the carriage, thereby to terminate carriage return movements, and means biasing said counterstop means to its normal position, said counterstop means and the carriage after terminating each carriage return movement, executing automatically a short movement in carriage advance direction to a left-hand margin position, in combination therewith, a control member for said carriage return clutch normally spring biased to an open clutch position but being positionable to close said clutch and be latched, a latch potentially effective under spring bias to latch said control member in closed clutch position whenever it is positioned to close said clutch, means on the frame responsive to the operation of said counterstop means in carriage return direction to said limit, to effect a releasing movement of said latch to an ineffective position and to allow the spring-biased control member to open the carriage return clutch, so that responsively the carriage and said counterstop means execute said short movement in carriage advance direction to said left-hand margin position, control means on the frame operatively responsive to the execution of said short advance movement of the carriage to the left-hand margin position incident to the carriage return operation, to block said counterstop means and, in turn, said carriage against movement in carriage return direction, and additionally to move to hold said latch in an ineffective position for as long as the carriage remains at said left hand margin position, whereby while said carriage is in said lefthand margin position there can be effected platen-indexing operations without carriage movement, said control means being operatively responsive to advance movement of said counterstop means incident to movement of said carriage from said left-hand margin position, to unblock said counterstop means for movement again in carriage return direction, and to again render said latch potentially effective, key means, and means cyclically operable under the control of said key means to position said control member to closed clutch position over an interval sufficient to operate said platen-indexing device.

Claim 3

The inventIon set forth in claim 1 wherein said control means includes a part movable into the path of said counterstop means in advance of said final limit stop.

Claim 4

The invention set forth in claim 1 wherein said control means includes a second part movable to block movement of said latch to its effective position.

Claim 5

The invention set forth in claim 1 wherein said cyclically operable means comprises a normally stationary cam on said power-rotated shaft means, a wrap spring clutch on said power-rotated shaft means, and means normally cooperative with said wrap spring clutch to cause it to be nongripping but through operation of said key means causing it to become gripping to transmit cyclic-turning movement to said cam when said key means is operated, said cam when executing a cyclic-turning movement whenever said carriage is in a position advanced from said left-hand margin position causing one operation of said indexing device followed by a carriage return movement, but while said carriage is at said left-hand margin position causing for every cyclic turning movement one operation of said indexing device without concomitant carriage movement.

Claim 6

In a typewriter having a frame, a carriage urged in an advance direction and being returnable, a platen and an operable platen-indexing device on the carriage, power-rotated shaft means on the frame, a carriage return clutch, means connectable by said carriage return clutch with said shaft means consecutively to operate said platen-indexing device and to draw the carriage in return direction, a carriage return margin stop on the carriage, a carriage-return-cushioning counterstop means on the frame operable thereon from a normal position a given distance to a final limit position by said margin stop through return movement of the carriage, thereby to terminate carriage return movements, and means biasing said counterstop means to its normal position, said counterstop means and the carriage after terminating each carriage return movement, executing automatically a short movement in carriage advance direction to a left-hand margin position, in combination therewith, a control member for said carriage return clutch being spring biased to an open clutch position but being positionable to close said clutch, a latch normally potentially effective under spring bias to latch said control member when it is moved to closed clutch position, means responsive to the operation of said counterstop means in carriage return direction to said final limit position, to effect release movement of said latch automatically to an ineffective position for causing the carriage return clutch to open and enable the carriage and said counterstop means to execute said short advance movement, control means on the frame responsive to said movement of said counterstop means incident to carriage advance to said left hand margin position to block then such counterstop means against movement in carriage return direction toward its final limit position and also to hold said latch released, and being further responsive whenever a carriage advance movement next takes place, to render said latch potentially effective again and to unblock said counterstop means for movement to its final limit in carriage return direction, a normally idle cyclically operable means which if it is operated while said latch is potentially effective, will position said clutch control member to become held by said latch in closed clutch position pending the operation of said counterstop means to its final limit by return movement of the carriage, and which cyclically operable means, if it is cyclically operated repeatedly while said latch means is in an ineffective condition will repeatedly operate the clutch control member to cause each time a clutch closure of automatically limited duration, a control key operable either to a first or to a second position, and means responsive to the operation of said key to sAid first position to limit said cyclically operable means to a single operation, and responsive to the operation of said key to said second position, while said control means blocks the counterstop means and holds the latch released, to cause, until said key is released, a number of operations of said cyclically operable means for effecting a desired number of line-indexing operations.

Claim 7

In a typewriter having a frame, a carriage urged in an advance direction and being returnable, a platen and an operable platen-indexing device on the carriage, power-rotated shaft means on the frame, a carriage return clutch, means connectable by said carriage return clutch with said shaft means consecutively to operate said platen-indexing device and to draw the carriage in return direction, a carriage return margin stop on the carriage, a carriage-return-cushioning counterstop means on the frame operable thereon from a normal position a given distance to a final limit position by said margin stop through return movement of the carriage, thereby to terminate carriage return movements, and means biasing said counterstop means to its normal position, said counterstop means and the carriage after terminating each carriage return movement, executing automatically a short movement in carriage advance direction to a left-hand margin position, in combination therewith, a control member for said carriage return clutch being spring biased to an open clutch position but being positionable to close said clutch, a latch normally potentially effective under spring bias to latch said control member when it is moved to closed clutch position, means responsive to the operation of said counterstop means in carriage return direction to said final limit position, to effect release movement of said latch automatically to an ineffective position for causing the carriage return clutch to open and enable the carriage and said counterstop means to execute said short advance movement, control means on the frame responsive to said movement of said counterstop means incident to carriage advance to said left hand margin position to block then such counterstop means against movement in carriage return direction toward its final limit position and also to hold said latch released, and being further responsive whenever a carriage advance movement next takes place, to render said latch potentially effective again and to unblock said counterstop means for movement to its final limit in carriage return direction, a normally idle cyclically operable means which if it is operated while said latch is potentially effective, will position said clutch control member to become held by said latch in closed clutch position pending the operation of said counterstop means to its final limit by return movement of the carriage, and which cyclically operable means, if it is cyclically operated repeatedly while said latch means is in an ineffective condition will repeatedly operate the clutch control member to cause each time a clutch closure of automatically limited duration, a control key operable either to a first or to a second position, and means responsive to the operation of said key to sAid first position to limit said cyclically operable means to a single operation, and responsive to the operation of said key to said second position, while said control means blocks the counterstop means and holds the latch released, to cause, until said key is released, a number of operations of said cyclically operable means for effecting a desired number of line-indexing operations.

Claim 8

The invention set forth in claim 5, wherein said cyclically operable means includes a cam member to position said clutch control member from open clutch to closed clutch position and thereafter to allow its restoration each time said latch becomes released.