Abstract: An intermittent drive mechanism for film is disclosed. A driven wheel having sprocket teeth for engagement in perforations in film is coupled by face teeth with the driving wheel and supported for turning about a common axis provided by a supporting shaft. The driving wheel is oscillated by an arm also supported on the common shaft. The teeth on both the driving and driven wheels have a saw-tooth shape and mesh to turn the ratchet wheel when the driving wheel is turned in one direction by the arm, and cooperate to move the driving wheel axially to an idle position when the driving wheel is turned in the other direction by the arm. Also disclosed is a bi-directional drive in which a driving wheel having face teeth on both lateral faces is provided and which is movable axially to bring one or the other sets of face teeth into operative engagement with axially spaced driven wheels having similar face teeth.

Abstract: Apparatus for blocking a cassette in a storage magazine having housings with slidable drawers adapted for receiving respective cassettes. The drawers can be retracted to a stored locked position in which a recall spring is compressed and when the drawer is unlocked, the spring displaces the drawer to an extended position. Studs are provided on the drawers for loosely engaging bores in reels in the cassettes and the recall springs can act directly or indirectly on the cassettes in the associated drawers, at least during retraction of the drawers, to take up the play between the studs and the reels thereby to block movement of the reels.

Abstract: A recording typewriter of the type including a memory arranged to record codes corresponding to typed characters as they are typed, and to drive the typewriter to type characters corresponding to stored codes. A single line readout is provided, preferably positioned between the typewriter keyboard and roller so as to be easily accessible to the view of an operator. The readout displays a selected line of characters as recorded in the memory. The particular line to be displayed is selected in dependence upon the typewriter elements associated with line control, such as the position or change of position of the typewriter roller or the actuation of the carriage return control. The system provides an economical and effective means of accessing stored data, allowing correction of stored documents, for example, to be easily accomplished.