Abstract: A typewriter comprising a shiftable carrier supporting a rotatable type drum having a plurality of circumferentially extending rows of type characters thereon. Typing keys, when depressed, condition actuators and cause engagement of a power driven cyclic action clutch which drives a power bail to operate a conditioned actuator to rotate the type drum from any position it may be in to a new position to align a type character corresponding to the key depressed with the printing point. Certain of the keys, when depressed, position stops to limit axial movement of the type drum by the action clutch to align an appropriate one of the rows of type characters with the printing point. The action clutch also actuates a centralizer to accurately align the type drum prior to printing and, in addition, causes printing. A cyclic carrier shift clutch is engageable by the action clutch and by certain carrier shift control keys.

Abstract: A normally closed wafer thin switch, particularly intended for pilferage type burglar alarms, comprising a flat base plate of insulating material having an opening therein and a pair of leaf spring contacts attached to one peripheral portion of the plate and extending over the opening. Free ends of the contacts normally engage each other to complete a circuit. A raised tab on a first of the contacts overlies an opposite peripheral portion of the plate whereby, when an object is placed on or against the switch, the tab is depressed against the plate, causing opening of the switch.

Abstract: A type drum comprising a shell formed as an open network of rows and columns with type characters being formed at the intersections thereof, the shell being attached at one end by struts to a hub located within the shell and spaced therefrom and a combination of the type drum and structure for releasably mounting the drum onto a support such that the drum may rotate relative to its support.

Abstract: A power driven typewriter comprising a shiftable carrier supporting a rotatable and axially movable flexible type drum having a plurality of circumferentially extending rows of type characters thereon. Type keys, when depressed, each condition one each of two groups of actuators and cause operation of a power driven cyclically operable clutch which drives a power bail to operate the two conditioned actuators, one of which is effective to rotate the type drum from any position it may be in to a new position and the other actuator being effective to raise or lower the type drum from any position it may be in to a new position to thus align a type character corresponding to the key depressed at the printing position. Upon alignment of a selected type character, the type drum is flexed radially to cause an imprint. Means are provided to dampen torsional oscillation, wobble, etc. of the drum prior to imprinting.