DEVICE FOR CUTTING-OUT HOLES IN ACTIVE PIPELINE Russian patent published in 2000 - IPC

FIELD: pipeline transportation of liquids and gases. SUBSTANCE: spindle shaft carrying cutting tool is provided with rotation and axial displacement mechanisms. They are combined and made as a reduction gear which includes worm-to-worm gear, draw-out carriage with gear and two toothed wheels. Wheels are positioned on spindle shaft coaxially and they can interact with each other through gear. The first toothed wheel is coupled with worm wheel of worm-and-worm gear. Number of teeth of the second wheel is less than that of the first one. Spindle shaft has threaded part on which hub of the second toothed wheel is mounted. Shaft may have fitting part and its diameter is equal to diameter of shaft threaded part. Protective screen is positioned on spindle in front of cutting tool. EFFECT: simplified construction. 3 cl, 5 dwg