Apparatus for drilling a circularly curved bore

An apparatus for forming in a workpiece a curved hole following a circular path, the apparatus comprising:

• a support shaped to at least partly engage said workpiece for fixing the support relative to the workpiece;
• a chassis pivotally mounted to the support on a means defining pivot axis, the pivot axis corresponding to a center of said circular path;
• a drilling bit mounted on a distal end of a shaft fixed to the chassis and a power transmission section connected to the drilling bit and disposed along an arc coaxial with the pivot axis, the power transmission section including a gear train defining a right angle and a spring disposed externally on a rod bent coextensively with the path;
• and,
• means for applying power to the power transmission section while forcing the chassis around the pivot axis, the drilling bit being guided through the workpiece with pivoting of the chassis relative to the workpiece and the support.

An apparatus for forming in a workpiece a curved hole following a circular path, the apparatus comprising:

• a support shaped to at least partly engage said workpiece for fixing the support relative to the workpiece;
• a chassis pivotally mounted to the support on a means defining pivot axis, the pivot axis corresponding to a center of said circular path;
• a drilling bit mounted on a distal end of a shaft fixed to the chassis and a power transmission section connected to the drilling bit and disposed along an arc coaxial with the pivot axis, a spring disposed externally on the shaft, the spring having helical windings with radially protruding surfaces and being rotatable on the shaft such that chips are carried backwardly from the drilling bit;
• and,
• means for applying power to the power transmission section while forcing the chassis around the pivot axis, the drilling bit being guided through the workpiece with pivoting of the chassis relative to the workpiece and the support.