| 摘要 |
A wrench comprises a rod, a retainer, and a casing for accommodating the retainer and allowing relative pivotal movement between the casing and the retainer. The rod comprises a driving portion on an end thereof for engaging with a fastener. The retainer has a first end securely mounted to the rod to turn therewith and a second end. An engaging member is mounted in the casing and biased to engaged with the second end of the retainer, thereby exerting an engaging force between the second end of the retainer and the engaging member. When a rotational force applied to the casing is smaller than the engaging force, the retainer and the rod are turned to thereby turn the fastener. When a rotational force applied to the casing is greater than the engaging force, the casing slides relative to the retainer while the retainer and the rod are not turned.
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