Abstract: A switchable flap valve having at least one valve plate (2, 2a, 2b) disposed for pivoting about a longitudinal axis in a housing part (1) for opening or closing a valve opening (11) provided in the housing part (1) in which a strip element (4, 4a, 4b) is formed on the upper side of the valve plate (2, 2a, 2b) aligned parallel to the longitudinal axis of the valve plate. The surface of the strip element (4, 4a) is inclined toward an adjacent housing wall (20) or toward a second strip (4b) and forms a hollow channel with the housing wall (20) or with the strip (4b). The free longitudinal edge (18) of the strip (4, 4a, 4b) is held in a latch mechanism (7, 8) to maintain the valve plate (2, 2a, 2b) in the closed position.

Abstract: A switchable flap valve having at least one valve plate (2, 2a, 2b) disposed for pivoting about a longitudinal axis in a housing part (1) for opening or closing a valve opening (11) provided in the housing part (1) in which a strip element (4, 4a, 4b) is formed on the upper side of the valve plate (2, 2a, 2b) aligned parallel to the longitudinal axis of the valve plate, The surface of the strip element (4, 4a) is inclined toward an adjacent housing wall (20) or toward a second strip (4b) and forms a hollow channel with the housing wall (20) or with the strip (4b). The free longitudinal edge (18) of the strip (4, 4a, 4b) is held in a latch mechanism (7, 8) to maintain the valve plate (2, 2a, 2b) in the closed position.

Abstract: The telephoto lens is in each case put together from two different lens systems, a front group and a focusing group. The object-side front groups have fixedly arranged lens elements or lens element groups and the image-side focusing groups have mutually displaceable lens elements or lens element groups. The focal lengths of the focusing groups are chosen such that with the front groups, they produce telephoto lenses of different overall focal lengths. The front groups can be combined in a modular manner with the focusing groups. Telephoto lenses having excellent imaging performances can be put together with reduced production expenditure. The numerical data of a number of lens parts are specified.

Abstract: An objective for use in photographic compact cameras has a relative aperture of 3.5 and a focal length of 35 mm, and is of the triplet type. The lens element on the object side is a cemented element. In order to achieve an extremely compact structural shape and balanced monochromatic correction, as well as a reduction in the chromatic magnification difference, the color coma and the color astigmatism, four design conditions are specified.