| CPC E21B 19/18 (2013.01) [E21B 12/00 (2013.01)] | 9 Claims |

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1. A system for replacing bits of a drill, the drill comprising a pivotable drill string with a percussion hammer receiving the bits at an end, comprising:
a decoupling wrench mounted on the percussion hammer, the decoupling wrench being movable between an extended position, in which the decoupling wrench is aligned with a drill hole of the pivotable drill string, and between a retracted position, in which the decoupling wrench is spaced away from the pivotable drill string, the decoupling wrench comprising:
a central slot to receive the bit coupled to the percussion hammer, and
a plurality of recesses located on an inner surface of the central slot, wherein the recesses are arranged to accommodate protrusions of the percussion hammer bit and prevent rotational movement of the bit when the bit is accommodated in the decoupling wrench;
a coupling wrench set up to apply torque to the percussion hammer when the bit is positioned in the decoupling wrench; and
a bit storage device comprising:
a bit cradle carriage set up to move on rail to align with the percussion hammer;
a bit housing comprising a wide range of receptacles connected by a shaft; and
a drilling control device of the drill set up to actuate the decoupling wrench, the bit storage device, the coupling wrench and the percussion hammer.
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