Abstract: The invention relates to a motor having a cuboid piezoelectric element (1) which carries an actuating member (2) for transmitting a force in an actuating direction (x). In known motors the piezoelectric element (1) is restrained by four restraining elements which are disposed in the plane of vibration (x/y plane) and which exert a preloading force on the piezoelectric element (1) in a direction perpendicular to the actuating direction (x). However, this gives rise to a frictional force between the restraining elements and the piezoelectric element, which reduces the vibration quality and, as a consequence, the motor power. This is avoided by means of the invention, where the piezoelectric element (1) is restrained by means of restraining elements (20, 21, 22, 23) without preloading, i.e. with maximal slidability in the directions (y, z) perpendicular to the actuating direction (x).

Abstract: The invention relates to a motor having a cuboid piezoelectric element (1) which carries an actuating member (2) for transmitting a force in an actuating direction (x). In known motors the piezoelectric element (1) is restrained by four restraining elements which are disposed in the plane of vibration (x/y plane) and which exert a preloading force on the piezoelectric element (1) in a direction perpendicular to the actuating direction (x). However, this gives rise to a frictional force between the restraining elements and the piezoelectric element, which reduces the vibration quality and, as a consequence, the motor power. This is avoided by means of the invention, where the piezoelectric element (1) is restrained by means of restraining elements (20, 21, 22, 23) without preloading, i.e. with maximal slidability in the directions (y, z) perpendicular to the actuating direction (x).

Abstract: A sheeting device having large-size sheeting panels (2,4) supported against vertical supports (1,3) which are arranged in pairs facing each other and are spaced-apart by at least one spreader frame (5). The side walls (15,15') of the supports (1,3) having a C-shaped cross-section are provided with legs (16,16') which are bent in parallel to the base wall (12), are opposing each other, and leave a wide gap between them. The spreader frame (5) is guided in the supports (1,3) in a vertically movable manner. The spreader frame is provided with rollers (11,11') transmitting pressure forces and running on the base wall (12) of the supports (1,3) and with rollers (17,17') running on the inner sides of the two legs (16,16') of a support (1,3) and transmitting the traction of the spreader frame.