Patent ID: 7658242
Filing Date: 2010-02-09
Classification: B23B,B28D,E21B,Y10T

Abstract:
1. An apparatus for drilling holes in a substrate, the apparatus comprising: a mandrel having a distal end portion and a proximal end portion coaxially aligned to the distal end portion, the distal end portion being smooth and cylindrical, the distal end being attachable to the substrate, the proximal end portion being threaded; a hollow tubular drill bit disposed about the distal end portion of the mandrel; a drive shaft fixedly attached to the drill bit and disposed about the mandrel; a bearing mounted within the drive shaft and seated on the distal end portion of the mandrel; an advancement portion which threadably engages the threaded proximal end portion of the mandrel and pushes the drive shaft toward the substrate; a power transmission box having an output sleeve disposable about the drive shaft and an input shaft wherein rotation of the input shaft is operative to rotate the output sleeve; a motor coupleable to the input shaft of the power transmission box and operative to rotate the input shaft; and a lever arm attached to the power transmission box for resisting a reverse torque created by rotation of the drill bit in the substrate.