Full-interlocking Kelly bar
全锁扣加压钻杆
Full-interlocking Kelly bar is composed of three weld-on ribs with continuous concave and convex keys (see chart) During the drilling process, the downward thrust is transmitted to drill bucket directly by rotation power of Rotary head inner ribs and Kelly bar outer ribs at any time . This type of Kelly bar is the best one of transferring pressure at present , especially for hard ground and frozen oil layer construction. In the drilling process , every continuous steps can form pressure point to reduce wear and tear of local pressurization key lines, also to avoid the stick problem that Kelly pipe is deformation always in a part pressurization. When drilling progress, driving the inner convex concave tooth key and the outer convex concave tooth key uniformly forms good engagement, the advantage is force uniform, not easy to stick pipe, particularly to improve work efficiency . It has gotten high praise from home and abroad rotary rig user.This type Kelly bar has applied for patent, the patent No. is 201420542679.2.
全锁扣加压钻杆是由三组带凹凸齿的键条等分组合而成（见图所示）。
全锁扣加压钻杆在钻孔过程中动力头旋转的内键与钻杆外键可以随时随处形成锁扣加压，直接将动力头上的加压力通过钻杆的凹凸齿直接全力传送到钻头上，目前这种钻杆传递加压力是最好的, 特别是对坚硬的地层及冻土层的施工。
在钻进过程中对钻杆每个部位都可以形成加压点，减少对始终局部受加压齿键条的磨损，也避免了钻杆始终在某一部位加压易造成管壁变形卡钻的难点，用时驱动内键均布的凹凸齿键与外凹凸齿键形成良好的啮合，在加压的部位形成多点加压，受力均布稳定不易卡钻，尤为提高工作效率，从而得到很多旋挖用户的好评。
该钻杆已申请专利，专利号：201420542679.2
