Abstract: A data printer having removable, and interchangeable, paper-feed modules, such as may embody a tractor or pin-feed-type paper-feed mechanism. The interchangeable modules each have guide ways which cooperate with and move along complementary guideways supported by the printer main frame to guide the selected module into place and seat it in a particularly defined position. A mechanical latch locks the seated module to maintain it in place. The paper-feed mechanism of each module is driven by a rotatable member, with the power train including a motor-driven worm mounted on the printer and a mating worm-gear carried on the removable paper-feed module. The worm is mounted in an upright position, and the worm-gear moves into mating relation with the worm by travelling an upright path, but with a small acute angle between such paths. The worm and worm-gear have a tooth or thread profile with a rounded nose section.

Abstract: A dot matrix impact print head uses a combination of cooperating forces produced by a deflected spring and dual electromagnetic fields to increase the striking force of a printing wire or needle element without adversely affecting operating frequency capabilities.

Abstract: A data recorder/reproducer device for disc media, particularly limply flexible magnetic disc media, having a pair of door-like structures mounted on opposite sides of a supportive frame, each such structure defining a narrow slit-space for receiving a recording disc and its envelope and mounting the same for recording, with a drive shaft supported on the frame centrally thereof, having a drive hub at either end aligned with the central opening in the recording disc, such that both discs are driven by the same drive train. The device has at least two recording heads, one for each disc, and the heads are articulated for selective control of movement toward or away from their particular disc, into or out of transducing relation thereto; also, the heads are mounted for translational movement across the face of their respective discs, generally radially thereof.

Abstract: A data recorder/reproducer device for flexible magnetic disc media, having a door-like structure mounted on a supportive frame. The door structure receives a recording disc and is adapted to carry a recording head at one or both sides of the disc. The heads are articulated for selective control of movement toward or away from the disc, into or out of transducing relation and also for translational movement across the face of the disc, generally radially thereof. The device includes novel interlocking actuator means which prevent opening of the door or doors except when the heads, positioned by a translational drive means, are in a predetermined "home" or start position at the edge of the disc, thereby preventing the inadvertent erasure or other loss or destruction of the recorded information.

Abstract: A diametrically-enlargeable cylindrical drum portion, preferably comprised of a plurality of movable segmental elements, each of U-shaped or other configuration having a pair of spaced legs or sides, which are resiliently flexible toward one another, mounted in a circuitous pattern on a rotatable member to form outwardly-projecting inner and outer generally concentric annular shoulder formations. The outer such formation provides a segmented hub for receiving a disc by its center opening, such hub being expandable against the opening in the disc to center the latter, as a result of moving a tapered actuator against the inner such annular formation, such actuator preferably comprising a conically angled ridge formation on a rotatable element which is movable into registering contact with the first such member.