| 摘要 |
Making the cross-sectional shape of the upper surface cover (5), which is supported on the stationary part-side (9a) near the two ends of the stroke of the mobile part, to be a shape that exceeds the width of a flat plate, prior to bending of the cover material, by a mere 1-2% for a V-shaped cross-section or 17% for a U-shaped cross-section, makes it possible to increase the second moment of the cover cross-section by fourteen- to seventeen-fold without changing the thickness (t) of the cover material, thereby making it possible to provide a cover, with which there is no danger of contact with the mobile part, at low cost even in a limited space. |
