Clutch mechanism for gripping tools

A generally axisymmetric clutch mechanism having a longitudinal axis and comprising:

• (a) a drive clutch body having a drive bearing surface and a frustoconical drive clutch surface;
• (b) an intermediate clutch body having a frustoconical intermediate clutch surface configured for sliding contacting engagement with the frustoconical drive clutch surface;
• (c) a driven clutch body having a driven bearing surface configured for transferring compressive axial force to the drive bearing surface;
• and
• (d) rotational drag means generating resistance to rotational slippage between the drive clutch surface and the intermediate clutch surface;
• wherein:
• (e) the drive clutch body, the intermediate clutch body, and the driven clutch body are coaxially aligned to the longitudinal axis of the clutch mechanism;
• (f) the intermediate clutch body and the driven clutch body are helically coupled in a first rotational direction relative to the longitudinal axis of the clutch mechanism, forming a first helical coupling having a first lead angle;
• and
• (g) the taper angle of the drive clutch surface and the intermediate clutch surface and the first lead angle are selected such that the clutch mechanism will lock when the drive clutch body is rotated relative to the driven clutch body in the first rotational direction.