| 摘要 |
The invention is concerned with a mine support crib of the type which comprises a series of superimposed layers of elongate chocks. There is a plurality of parallel, spaced apart chocks in each layer with the chocks in one layer arranged transversely to the chocks in the adjacent layer or layers so that the chocks in a given layer, other than the bottom layer, cross the chocks in the layer below at crossing points which are located inwardly of the ends of the chocks. According to the invention, operatively upper and lower surfaces of the chocks are formed with notches at the crossing points. The notches interlock with one another to lock the chocks together. The notches are of such depth that portions of the chocks which are located between and beyond the notches bear on corresponding portions of chocks in the next layer but one below.
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