Nailing depth adjusting and positioning device for a power nailer

A nailing depth adjusting and positioning device for a power nailer, comprising:

• a link moveably mounted on the power nailer having a nose rod on a first end of said link to connect to a trigger of said power nailer, a connection plate extending laterally from a second end of said link, said connection plate having a sleeve and a top plate defined in a distal end thereof, a step hole formed in said sleeve and a circular groove defined adjacent to an opening of said sleeve, said opening of said sleeve facing toward a muzzle of said power nailer, said step hole having a bigger bore at its upper position and a smaller threaded bore at its lower position, said circular groove defined two through holes in connection with said step hole;
• a spring having a first end mounted to said sleeve and a second end contacting a body of said power nailer;
• a rotatable member including a wheel body, a step rod and a positioning rod, said wheel body having a plurality of anti-sliding threads on a surface thereof, said step rod formed at a side of said wheel body and received in said step hole of said sleeve, said step rod including a screw section, a sliding section and a ring section, said screw section having a plurality of threads on a surface thereof and located at a first end of said step rod, said screw section threadly engaged with a smaller threaded bore of said step hole, said sliding section located at a second end of said step rod adjacent to said wheel body, said ring section located between said screw section and said sliding section, a side of said ring section formed a stopper due to the diameter of said ring section being bigger than the diameter of said sliding section, the length of said sliding section being shorter than the length of said screw section, in addition, said positioning rod having a circular groove defined threreon and a recess hole defined between said circular groove and said wheel body, a spring and steel ball put into said recess hole in turn;
• a push member having a crown bar in correspondence with a work piece and a positioning seat extending laterally from an end of said crown bar, said positioning seat having a central hole defined therethrough and a plurality of gaps defined on an inner periphery of the central hole, said push member mounted to said positioning rod and said steel ball mating with one said gaps so that when said rotatable member is rotated, said steel ball can change the position from one gap to the other;
• a C-shaped fastener located in said circular groove so that said rotatable member will not disengage from said central hole of said push member.