Abstract: A device for opening and closing a curtain, notably in order to automate the phases of opening and closing the curtain, includes a track defining a rolling path followed by the carriage during the opening or closing of the curtain. In addition, there are transmission mechanisms designed to transform a rotational movement into a linear movement, activation mechanisms of the transmission mechanisms having the form of a motor instrument equipped with mechanisms for driving in rotation the transmission mechanisms, control mechanisms of the activation mechanisms, and drive mechanisms of at least one of the carriages, referred to as the head carriage. The drive mechanisms act together with the transmission mechanisms in order to transmit to the head carriage a linear movement corresponding to the rolling path.

Abstract: A position detecting system includes a sending unit in the form of a continuous conductor describing a Greek key pattern surrounded by a return-path conductor arrangement. The return-path conductor is so arranged as to provide additional legs of the pattern with the widths and spacings of such additional legs with respect to adjacent legs of the pattern being such as to assure a magnetic effect producing well defined and evenly spaced node and antinode signals in an associated pick-up head.