| 摘要 |
979,478. Grab buckets. PRIESTMAN BROS. Ltd. Sept. 4, 1963 [Oct. 1, 1962], No. 37136/62. Heading B8H. The upright side edges of a clam-shell grab are formed with serrations 11, Fig. 2, the depth of the serrations, the thickness of the walls and the gaps between the serrations being such that when the grab is filled with fine granular material having a natural angle of repose of 45 degrees the material heaps up on the upper flanks of the serrations and seals the sides of the grab. Fig. 4 shows in cross-section how the material M piles up on the serrations 10. The thickness of the walls can be reduced without affecting the seal if the serrations are inclined downwardly and inwardly as shown in the modified construction in Fig. 7. This construction also prevents material joggling out due to vibrations of the grab. The material M, Fig. 2, also piles up to form a seal on a lower overlapping lip 7 of the grab. |
