SCREW-NUT PAIR OF COGGING MILL Russian patent published in 2002 - IPC

FIELD: manufacture and exploitation of heavy rolling mills in machine engineering and metallurgical industry branches. SUBSTANCE: screw-nut pair of cogging mill including hollow screw and nut has screw with flat foot, cavity for collecting oil in head of screw and safety ring mounted on screw bead. Screw is in the form of funnel for collecting oil; said funnel has inclined through openings passing from funnel to screw cavity. Screw-nut pair also includes movable steel ring with upper cone surface turned to screw. Inner diameter of ring is equal to that of funnel. Ring is arranged over funnel in end turning of upper link of telescopic casing of screw. Nut includes bronze portion in the form of inverted cone united with steel casing having upper ring and lower ring with membrane mutually joined by means of shell. On lower end of nut there is annular groove with cone surface for introducing movable ring at upper position of screw jammed in nut. Under flange of upper link there are inclined through threaded openings closed by plugs. When screw is jammed in nut, through said openings flame of gas-oil cutter heats lower portion of movable ring. Heated ring by action of effort of elastic deformation of screw and nut moves upwards for releasing screw. Supporting bronze ring with spherical surface is placed between end of turning of mill frame and nut that is why nut with screw may perform oscillations in frame but it does not break by action of large horizontal force upon screw foot at rolling strip. Thread of screw-nut pair has equal-strength turns. Screw is accurately centered in nut; turns of screw-nut pair are cooled by flooding oil. Lubrication system of screw-nut pair provides flood lubrication of friction zones at rotating screw and removal of lubricant at arresting screw. It provides enhanced strength of screw-nut pair and creation of high braking momentum against unscrewing and against releasing upper roll. Turns of screw-nut pair are heated insignificantly due to their cooling by flooding oil that is why water cooling is not realized. Such screw-nut pair provides high quick-action of screw-down apparatus of cogging mill without releasing screws. EFFECT: increased strength, uniform wear of parts of screw- nut pair during long time period due to rational lubrication system in dependence upon modes of screw operation, elimination of screw releasing. 8 dwg