| 摘要 |
<p>1502898 Deformable mine support MINE SUPPORT SYSTEMS (PTY) Ltd 2 Sept 1975 [5 Sept 1974] 36173/75 Heading E1E A mine prop comprises at least one elongate timber element 16 surrounded by at least one sleeve 10, 12 of ductile metal, with the grain of the timber parallel to the axis of the sleeve(s), whereby, when an axial load is applied to the prop, it gradually reduces in length, the ductile sleeve(s) being deformed and containing the compressed and transversely expanding timber. Preferably there are two sleeves telescopically engaged as shown, each holding tightly a respective timber element, with a spacer 20 for initial adjustment of the length.</p> |
