Two-piece fastener air hammer

A powered impacting device comprising:

• a first, inner, piston;
• a second, outer, piston concentric with said first piston;
• means for receipt of a two-piece fastener, having concentric inner and outer components, in operative relationship with said pistons so that said outer component is driven by said second piston, and said inner component is driven by said first piston;
• and means for supplying pressurized fluid to said pistons so that said second piston contacts said outer component and drives it axially in a given direction, and then said first piston contacts said inner component and drives it axially in the same direction, moving relative to said second piston;
• wherein the improvement comprises
• said means for supplying pressurized fluid to said pistons comprising means for supply fluid to said second piston fluid, and then for supplying fluid to said first piston, to first drive the outer fastener component to self-pierce a workpiece, and then to drive the inner fastener component to deform the outer component into locking relationship with the workpiece;
• said means further comprising first and second triggers operatively associated with a first handle for the device and first trigger for effecting supply of fluid to said first piston and said second trigger for effecting supply of fluid to said second piston, and means connecting said triggers so that said first trigger cannot be actuated to supply fluid to said first piston until said second trigger has been actuated to supply fluid to said second piston.

A powered impacting device comprising:

• a first, inner, piston;
• a second, outer, piston concentric with said first piston;
• means for receipt of a two-piece fastener, having concentric inner and outer components, in operative relationship with said pistons so that said outer component is driven by said second piston, and said inner component is driven by said first piston;
• and means for supplying pressurized fluid to said pistons so that said second piston contacts said outer component and drives it axially in a given direction, and then said first piston contacts said inner component and drives it axially in the same direction, moving relative to said second piston;
• wherein the improvement comprises
• safety means for preventing supply of actuating pressurized fluid to said pistons unless said device is in contact with a surface into which said fasteners are to be driven.