Abstract: There is provided a composition for the care and maintenance of water-resistant surfaces, which contains the following components:

Abstract: The present invention relates to a device for continuously monitoring the junction of a conveyor belt which is made of rubber or a rubber-type plastic material and which comprises supports inserted therein for reinforcing the same. In an advantageous embodiment, the device essentially comprises the following constituent members for the junction area: mainly four reference marks, two addresses as well as four detection heads, the heads being located above the carrier surface of the conveyor belt. This invention further relates to other advantageous embodiments of this device.

Abstract: A photoelectric keyboard for typewriters and similar machines comprises two parallel plate modules spaced one above the other, the upper plate module comprising a plate of transparent material having holes supporting and guiding light transparent depressible key stems, and having cutouts supporting light sources, and the lower plate module comprising a printed circuit board supporting photo elements opposite the ends of key stems. The ends of the transparent key stems are, in normal position, spaced a predetermined optical distance from the photo elements arranged on the lower plate such that the light radiated from the ends of the key stems is insufficient to activate associated photo elements. On depressing a key, the distance between the end of the key stem and an associated photo element is reduced and the light beam radiated from the end of the key stem is sufficient to activate the associated photo element. Thus only the corresponding photo element is activated by a depressed key.