Importance

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Abstract

A ratchet drive comprises a support on which a ratchet gear is mounted turnably about a first pivot axis. A lever is mounted on the support tiltable about a second pivot axis spaced from and parallel to the first pivot axis between a forward stroke and a return stroke. A pair of drive pawls are mounted at one of the ends thereof on the lever tiltable about axes located spaced from and respectively to opposite sides of the second pivot axis and engaging with the other end thereof the ratchet gear, so that when the lever is moved along its forward stroke, one of the drive pawls will engage a tooth of the ratchet gear to turn the latter in one direction while the other pawl moves rearwardly over a tooth and so that during the return stroke the other pawl engages a tooth of the ratchet gear to turn the latter in the same direction while the one pawl moves rearwardly over a tooth. The ratchet drive may be used for turning a threaded connector, in which case a ratchet gear is either provided with a polygonal passage therethrough adapted to engage with the polygonal head of a threaded connector to be turned or with a coaxial projection of polygonal cross section extending beyond the support on which a socket for engaging the head of a threaded connector is exchangeably mounted. The lever may be moved along its forward and its return stroke by a fluid operated cylinder-and-piston unit mounted on the support.

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First Claim