Barrel unit with a removable cover plate for a pneumatic nail driving device

A barrel unit adapted to be installed on a front end of a pneumatic nail driving device, said barrel unit comprising:

• an elongated base plate having a top face formed with a longitudinal nail discharge groove, a pair of upwardly extending hooking lugs which are disposed respectively on opposite sides of said discharge groove and which are located at a front portion of said base plate, and a pair of upwardly extending first pivot ears which are disposed respectively on said opposite sides of said discharge groove and which are located at a rear portion of said base plate;
• an elongated cover plate superimposed on said top face of said base plate to cover said discharge groove, and having a pivot end pivoted to said first pivot ears of said base plate, a pair of upwardly extending second pivot ears between said pivot end and said hooking lugs, a pair of abutment tabs projecting sidewise and respectively from said second pivot ears, and a pair of shoulders disposed behind said hooking lugs;
• and
• a latch unit including an operating lever formed with a pair of third pivot ears mounted pivotally on said second pivot ears of said cover plate in such a manner that said third pivot ears of said operating lever slidably and respectively contact said abutment tabs, and a U-shaped clasper connected pivotally to said operating lever and detachably engaging said hooking lugs;
• whereby, after disposing said clasper around said hooking lugs, rearward pivotal action of said operating lever about said second pivot ears results in tight engagement between said clasper and said hooking lugs and subsequently causes tight engagement between said third pivot ears of said operating lever and said abutment tabs, and tight engagement between said shoulders and said hooking lugs, thereby tightening said cover plate on said base plate.