| 摘要 |
The ratchet spanner is a tool which is used predominantly in mechanical engineering and repair work. Particularly in technical fields, it happens that hexagon head screws or nuts are positioned so that it is possible to get hold of them only by means of a fork spanner, and even then only under the most difficult working conditions can the screw or nut be loosened and unscrewed. The ratchet spanner is made specially for this problem. By means of a ratchet in the head of the spanner, it is possible to unscrew a hexagon head screw or nut without a complete rotation of the spanner being necessary.
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