| 摘要 |
The invention relates to a screw driver meant to be used for mounting screws in hardly accessible places, which has the possibility of maintaining the contact between the screw driver head and the screw head, independently of the operator. According to the invention, the screw driver has fixed on the driving handle (1) a metal rod (2) provided with the screwing head (a) and also with some shoulders (b and c) with some helicoidal springs (3 and 4) mounted therebetween, which are separated from/by a shoulder (d), cut on some elastic shims (e) of an interior bush (5) mounted on the metal rod, and which is provided with an external thread (f) onto which an external bush (6) may be screwed /unscrewed, said bush being provided with an interior thread (g).
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