| 摘要 |
<p>TITLE DRILL HEAD ASSEMBLY A drill housing include an internal cavity for receiving a unitary tubular support member rotatably supported by bearing assemblies in the drill housing. The tubular support member is connected through meshing gears to a drive shaft of a rotary motor mounted externally on the drill housing. An upper end portion of the tubular support member is rotatably supported by a first bearing assembly and is nonrotatably connected to a drill retaining member that extends into a central bore of the tubular support member. The drill retaining member has a socket for receiving the shank of a drill steel. A lower end portion of the tubular support member is rotatably supported by a second bearing assembly. An enlarged intermediate body portion of the support member separates the upper and lower end portions and supports the first and second bearing assemblies. The lateral thrust of the drill steel is applied to the enlarged intermediate body portion and thereby removed from the bearing assemblies to reduce wear of the bearing assemblies. A carrier member is positioned in an annular space between the tubular support member lower end portion and the drill housing. The carrier member supports a plurality of overlying O-ring seal members in surrounding relation with the tubular support member to prevent loss of lubricant from the second bearing assembly and the entrance of rock cuttings and dust into the drill housing.</p> |
