US PATENT SUBCLASS 400 / 329
.~.~ Carriage escapement controlled by pawl

Current as of: June, 1999
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400 /   HD   TYPEWRITING MACHINES

283  DF  CARRIAGE OR CARRIAGE-MOVING OR MOVEMENT-REGULATING MECHANISM {11}
319  DF  .~ Carriage-feed mechanism (e.g., escapement, etc.) {14}
329.~.~ Carriage escapement controlled by pawl {5}
329.1  DF  .~.~.~> Means to ensure engagement of pawl at start of print-line (i.e., overbanking control)
329.2  DF  .~.~.~> Carriage-feed initiated and completed during depression of character key (e.g., "speed" or "reverse" escapement)
329.3  DF  .~.~.~> Pawl rocker spring regulating device
330  DF  .~.~.~> Via ratchet wheel connected to pinion and carriage-rack {5}
332  DF  .~.~.~> Via toothed rack {3}

DEFINITION

Classification: 400/329

Carriage escapement controlled by pawl:

(under subclass 319) Subject matter wherein the carriage* is urged by a source of power to be moved in a direction for

imprinting successive character* symbols on the record-medium* (e.g., a character-space* direction), and the movement in said direction is regulated by a mechanism that (a) restrains the carriage against movement, and (b) releases the carriage momentarily to be urged to move, and (c) again restrains the carriage against movement, which mechanism includes a member or members having movement relative to the carriage or to a portion connected thereto, the relative movement between the member(s) and carriage effecting the restraint and momentary release of the carriage to produce the increments of movement corresponding to character-space and word-space* distances.

(1) Note. The regulating mechanism defined above is usually a pawl* and ratchet* mechanism as these members are defined in the Glossary, section III.

(2) Note. Movement of the carriage during carriage feed is related to movement of the type-face* element to the print-point* for impressing the type-face against the record-medium*. These movements occur in various terms applied in the typewriter art. In all the sequences a typist initiates the operation by pressing a key* element which causes movement of a type-face (e.g., a type-face on a type-bar*, a type-face on a type-head*, etc.) from its rest position. In "full-drop" escapement the sequence is (a) the type-face is impressed at the print-point, (b) the carriage starts its movement through a full character-space distance, and (c) the carriage completes a character-space and stops. In a "half-drop" escapement the sequence is (a) the carriage starts its movement but stops momentarily approximately halfway in a character-space, (b) the type-face is impressed at the print-point, and (c) the carriage continues its movement through the remainder of the character-space. In "speed" escapement (also known as "reverse" escapement) the sequence is (a) the carriage starts its movement through a full character-space distance, (b) the carriage completes a character-space and stops, and (c) the type-face is impressed at the print-point. In all the sequences the type-face is returned to its rest position and the key* is also returned to its rest position. The differences between the various sequences are primarily in the time available to enable a type-bar (which carries the type-face element) to move from rest position to print-point position and back to rest position (a) as related to the time available for a next-actuated type-bar to perform the same movements without interference from the previously actuated type-bar, and (b) as related to the time available to move the carriage through a carriage space.