| 摘要 |
1396190 Testing & grading timber SOUTH AFRICAN INVENTIONS DEVELOPMENT CORP 21 Dec 1972 [23 Dec 1971] 59092/72 Heading G1S A rough sawn timber beam 10 is test loaded as at 16 by a pneumatically operated piston 24.1 which bears down on a roller 26 rotatably mounted in a vertically movable yoke 28. A deflection dial gauge 30 may be rotated by pulling down on an operating strip 32 depending between a pair of gripping jaws 34.1, 34.2 on a clamp 34. In operation, the jaw 34.2 is first closed upon the jaw 34.1 by downward pivoting of the lever 36 as the shoe 24.2 moves down to engage and pre-load the roller 26. Further movement downwardly of the shoe 24.2 then moves the roller 26 and the yoke 28 downwardly to apply a working load to the roller and timber beam and pull down on the strip 32. The cross-sectional dimensions of the beam 10 are then compared with the deflection obtained by applying a pre-load and then an increased working load, and these loads and deflections are then referred to a prepared table . of related loads, nominal and actual measurements and to deflections to determine the particular grade of the timber beam under test. |
