Drill head unit

A drill head unit for transmitting rotational power from a horizontally oriented motor to a vertically oriented hollow drill bit comprising:

• a housing having a first cavity therein for enclosing a gear assembly,
• a first bevel gear mounted in said first cavity and journaled for rotation about a vertical axis,
• a drill chuck on said first bevel gear, said drill chuck for accepting a hollow drill,
• a shaft extending downwardly below said first bevel gear, said shaft having an axial hole for communicating with an opening in a hollow drill fitted in said drill chuck,
• means for transferring rotational power from said first bevel gear to said drill chuck,
• a second cavity in said housing below said first bevel gear, said second cavity being in communication with said axial opening in said shaft,
• a tubular member having an inner wall, said inner wall of said tubular member forming an inner wall of said second cavity,
• a port in said housing opening into said second cavity through which a fluid may flow,
• a bevel pinion mounted in said first cavity and journaled for rotation about a horizontal axis, said bevel pinion being adapted to engage said first bevel gear,
• attachment means for attaching said bevel pinion to the shaft of a motor,
• first sealing means for sealing said first bevel gear against said housing,
• second sealing means for sealing said bevel pinion against said housing,
• one of said tubular member and said shaft having an annular groove therein, said annular groove extending axially and having a substantially cylindrical inner side surface, and a substantially cylindrical outer side surface
• an annular seal attached to the other of said tubular member and said shaft, and
• said annular seat having an inner sealing lip for sealing radially against said inner side surface of said annular groove and having an outer sealing lip for sealing against said outer side surface of said annular groove.