.~ For interlocking plural functions or mechanisms {2}
666
.~.~ Plural keys or key linkages (e.g., for type-face selection, etc.)
DEFINITION
Classification: 400/666
Plural keys or key linkages (e.g., for type-face selection, etc.):
(under subclass 664) Subject matter wherein a typewriter is provided with at least two key* elements or at least two sets of lever arrangements for transmitting movement of a key into movement of a type-head*, and wherein the typewriter is also provided with an interlock for preventing one of the keys or lever arrangements from being effective to operate when the other is operating.
(1) Note. In a typewriter of this subclass when a first key has been fully depressed to cause operation of a first type-bar* a second key can be moved to a small extent, but will not cause operation of a second type-bar; or simultaneous full depression of two keys is prevented, thereby preventing simultaneous operation of two type-bars. See subclass 667 for a key-board* lock using an interlock mechanism so that no key may be moved.
(2) Note. Also in this subclass, the interlock means may include: an electrical interlock, an interlock including a plurality of elements that are displaced to prevent intrusion of a second key lever when a first key lever has displaced the elements, a flexible strip that is tautened to prevent a second key lever from being moved when a first key lever has
tautened the strip, and a plate that is shifted by one key lever to prevent movement of a second key lever, the mechanisms described being only exemplary of those found herein.
