| 摘要 |
The folding ruler comprises a number of identical sections joined in pairs to each other. There is a joint fixture at each union point between a pair of sections, and an overlap between rows at the joints. This allows the ruler to be folded up to form a stack of identical parallel sections, and then folded out, one section after another, in a straight line. - At least one of the sections in a pair is displaceable longitudinally over its complete length relative to the point of union, and aligned sections in the ruller can adopt a total measurement length differing from whole number multiples of stick length. Each section includes an additional scale indicating the extent of the displacement from a non-displaced normal position. (Provisional Basic advised week 8431)(0/14) |
