CUT-OFF PLATE Russian patent published in 1997 - IPC

FIELD: oil and gas production. SUBSTANCE: invention relates to hole drilling and may be used to cut off pipe passage. In the body of assembly, ball locking device is set up on saddles. Between saddles and body, a spring and seals are located. Drive is of lever-screw type and is placed on bearing plate. This plate is rigidly bound with lever and may rotate about axis of revolution of ball locking device and interact with ball locking member revolution limiters disposed on bearing plate. When screw transmission is involved, manufacture process is simplified. The two elements of screw-nut transmission are machined on multifunctional screw-cutting lathe with normal grade of accuracy. Bearing plate serves to provide correct interposition and correct interaction of drive constituents. Interaction of lever-screw drive support with revolution limiters enables accurately fixing on-off positions of ball locking device. Accuracy in on-position fixation is necessary to provide equal passage of cut-off plate and ensuring specified cut-off plate endurance by way of preventing erosion of edge of ball locking device caused by working medium. Accuracy in off-position fixation is necessary to prevent working medium from leakage. EFFECT: facilitated pipe passage cut- off. 5 dwg