The invention discloses a forward-type full-automatic controllable variable-
diameter pressure relief connecting rod drilling bit device and a using method thereof, and relates to the field of large-
diameter drilling for pressure relief in
metal mine mining or
coal mining. The forward-type full-automatic controllable variable-
diameter pressure relief connecting rod drilling bit device comprises a drilling bit, a pressure relief connecting rod and a connecting rod end head, the pressure relief connecting rod comprises a pressure relief connecting rod main body, a diameter-expanding
cutting head,a fixed cutter head, a supporting diameter-expanding rod, a sliding connecting wedge, a trigger
piston, a spring, a sliding fixed plate and a
limiter, the diameter-expanding
cutting head, the fixed cutter head and the supporting diameter-expanding rod are connected with one another, and the fact that each part reciprocates in a rail under the action of
water pressure / air pressure through the trigger
piston is achieved, so that the expansion and retraction of the diameter-expanding
cutting head are achieved. The forward-type full-automatic controllable variable-diameter pressure relief connecting rod drilling bit device effectively realizes full-automatic diameter change, controllable hole expanding diameter and whole process
powder discharge in the process of drilling, and the device andthe using method thereof can meet the pressure relief effect, meanwhile, reduces the damage of pressure relief drilling to the surrounding rock at a certain depth on the roadway surface and further improves the construction efficiency.