Abstract: A periodical switching device has adjustable periodic ON durations and has rapid on, off transitions. A swinging member rides on a rotating cam. An operation member controlled by the cam and by the swinging member turns a switch on when the cam moves the operation member and turns the switch off when the cam moves the swinging member to release the operation member. An adjusting member changes position of the swinging member to vary its point and time of initial contact with the cam to selectively control release of the operation member which turns OFF the switch. A feeding device advances the adjusting means to 100 percent conduction when the adjusting device is moved to select about 83 percent or more conduction. An old setting-clearing device moves the operation member relatively to the swinging member so that the members follow the newly set durations immediately upon beginning new cycles.

Abstract: A rotary transmission between a "minute" display mechanism and an "hour" display mechanism is disclosed for use in a digital clock of leaf type. The transmission is disposed between a first bobbin supporting minute's display members and a second bobbin supporting "hour's" display members. The first bobbin carries a planetary gear, which meshes with a ring gear as well as a driven gear formed on the second bobbin. The ring gear has a number of teeth which is different from the number of teeth on the driven gear.