... platform combined with parallelogram amplitude varying device makes boring tool position rapidly and accurately.3.8 Drilling ... .5We are Shandong Hongda Construction Machinery Group Co., Ltd., a professional construction machinery manufacturer with a history of ... luffing-jib, hammer-head, flat-top, multi-speed, stepless-speed), Construction Elevators(multi-speed, stepless-speed), Concrete Mixers (rotary ...