GLIDING SUPPORT OF TOOTHED-ROLLER SCRAPER Russian patent published in 1997 - IPC

FIELD: oil and gas production equipment. SUBSTANCE: in gliding support of toothed-roller scraper containing knuckle and rolling cutter with coupled gliding surfaces forming radial and thrust bearings with clearances permitting restricted displacement and skewing of axis of rolling cutter in respect to knuckle as affected by reaction of borehole bottom, initial regions of these clearances are narrowed inwards by 0.3 their length in direction to apex of rolling cutter in radial bearings and from outside diameter of knuckle toward its axis in thrust bearings. Clearances in slider bearings are separated into three regions and, when the end of rolling cutter is displaced under bottom reaction upward to a greater value than its apex value, in the middle main region with length constituting 0.4 working length of clearance, clearances are executed narrowed at angle β between generatrices of knuckle and rolling cutter, which angle is equal to expectation value of angle of azimuth of axis relative to knuckle axis. In the end region, clearances are expanded for radial bearings with angle between generatrices of knuckle and rolling cutter equal to 3 quadratic mean deviations S_β of angle of azimuth β and being constant for thrust bearings. In the initial region, angle between the two generatrices equals 3S_β+β and, when the end of rolling cutter is displaced under bottom reaction upward to a greater value than its end value, in the middle main region clearances are executed expanded at angle β; in the end region, angle between generatrices of knuckle and rolling cutter is equal to 3S_β+β; and in the initial region, 3S_β-β. EFFECT: improved design.