A drilling device for removing a spot-welded portion, said device comprising:
- a main body casing having a forward end;
- a chuck receiving holder fixed rigidly to said forward end of said main body casing;
- a U-shaped arm having a first end fixed to a side portion of said chuck receiving holder, a base shoulder portion adjacent said first end, and a free second end spaced forwardly of said forward end of said main body casing;
- a chuck receiver extending into said forward end of said main body casing and axially slidable with respect thereto, said chuck receiver having extending therefrom a flange for abutment with said chuck receiving holder, thereby to restrict axial movement of said chuck receiver into said main body casing, said chuck receiver having formed therein an engaging groove;
- a chuck received within said chuck receiver and axially slidable therewith, said chuck having formed in a forward end portion thereof an axial bore, said chuck having therein longitudinal split grooves, and said chuck having therearound external threads;
- a drill extending into said axial bore in said forward end of said chuck and directed toward said free second end of said U-shaped arm;
- socket means having internal threads and threaded over said chuck for tightening said chuck onto said drill;
- means for rotating said chuck with respect to said chuck receiver and said main body casing, and thereby for rotating said drill, said rotating means comprising a rotary shaft extending into said chuck and adapted to be rotated by a motor mounted in said main body casing, and means for connecting said rotary shaft and said chuck to prevent relative rotation therebetween while enabling relative axial movement therebetween;
- first bearing means between said main body casing and said rotating means to enable relative rotation therebetween;
- second bearing means between said chuck and said chuck receiver to enable relative rotation therebetween;
- means for moving said chuck receiver, said chuck and said drill axially of said main body casing toward said free second end of said U-shaped arm, said moving means comprising a grip handle pivotally mounted on said base shoulder portion for movement between a first position relatively spaced from said main body casing and a second position relatively toward said main body casing, and a chuck thrusting arm integrally connected to said grip handle and having a pin fitting in said engaging groove and thereby engaging said chuck receiver such that, upon movement of said grip handle from said first position thereof toward said second position thereof, said chuck thrusting arm moves said chuck receiver, and thereby said chuck and said drill, axially with respect to said main body casing and said rotating means toward said free second end of said U-shaped arm;
- means for adjustably restricting the length of said axial movement, said restricting means comprising a screw mounted on said grip handle and having an end abutting a surface of said base shoulder portion when said grip handle is in said second position thereof, said screw being mounted to adjust the relative position of said abutting end with respect to said base shoulder portion;
- and
- means on said main body casing for operating the motor for rotating said rotary shaft, and a lever pivotally mounted on said main body casing for movement between a first position spaced from said operating means and a second position actuating said operating means, said lever being positioned such that movement of said grip handle to said second position thereof moves said lever to said second position thereof, thereby rotating said rotary shaft.