Patent GB-642767-A (GB)
Title: Improvements in or relating to rolling mills for flat articles
IPC: B21B31/18
Filed: 1947-12-18
Abstract: 642,767. Cold-rolling. TRIGGS, W. W. (Sendzimir, T.). Dec. 18, 1947, No, 33403. [Class 83 (iv)] In a rolling-mill having small diameter work rolls backed by intermediate rolls located between the work rolls and casters supported on the housing beams, certain of the casters and intermediate rolls are located to withstand a component of the rolling pressure at a large angle to the vertical while at least one caster and intermediate roll sustain a portion of the rolling pressure in a direction more nearly vertical, the sizes of the casters and intermediate rolls being proportioned to the magnitude of the components of rolling pressure so borne by each. The work rolls 1 are supported by casters 7-10, Fig. 1, which are carried on shafts 5 having eccentric discs 6 keyed thereto and carried in saddle elements 4 engaging in recesses in the mill housing beam 40A. Each saddle- and caster assembly is looked in the recess by a slidable tapered bar 12 having a toothed end section co-operating with a worm 13. Caster assemblies 8, 9 sustain smaller components of the rolling pressure and may be staggered, the casters being interdigitated, Fig. 2, or of lesser diameter than the caster assemblies 7 and 10. Rotation of the shafts 5 by means of toothed rods 16 and gears 15 effects screw down of the mill. Operation of the rods 16 may be effected hydraulically through a valve 18, with which a rolling pressure relief valve 20 may be associated. In modifications, shafts 5 may be split to obtain within the shaft a cavity 21, Fig. 2, filled with pressure fluid so as to collapse under excess rolling pressure, or the caster assemblies may be mounted in a cradle journalled in a recess in the mill housing, which recess is eccentric to the work axis, so that the roll pressure tends to turn the cradle in the recess against a spring- loaded stop, Fig. 3 (not shown). The tendency of the work rolls to deflect more in their centres than near the edges is overcome by forming a taper relief on one end or both ends of the work rolls or any series of intermediate rolls as in Fig. 6. The rolls may be provided with axial adjustment for the regulation of the taper position in relation to the work position. The deflections under load in the mill housing itself are greatest at a point corresponding to the centre of the strip being rolled and are counteracted by tapered edge portions of the beams 40A, Fig. 8. Rolls in the upper half of the mill other than the work roll are held suspended by springs 26, Fig. 9, or air-operated piston rods, and axial movement of rolls not intended to be movable axially is limited by mill doors 76 and bearing blocks 25. The driven ends of the driven rolls are engaged by sliding them into the ends of spindles 33 from which the rolls may be removed upon opening of the mill doors 76. Lubrication and cooling of the caster bearings may be effected by lubricant delivered through bores in the shafts 5 and axial openings therefrom to the bearings, the escaping lubricant cascading over the upper rolls and escaping through the mill windows W, or the bearings may be sealed and a lubricant circulated continuously, Fig. 7 (not shown). The rolls and workpiece may be flushed with lubricant supplied under high pressure through jets 67, Fig. 4, whose direction is inclined from the normal to the roll axis so as to give the lubricant an acceleration away from the centre of the mill. Lubricant may be sealed in the upper and lower halves of the mill by resilient seals 60. Flexible strip metal scrapers 55 are held in holders 66 provided with spaced slots 56 through which lubricant may escape. The rolled strip is wiped by a flexible hose 58, preferably of synthetic rubber, and having an internal metal core. Bores 62 in the lower half of the mill let out some of the lubricant and prevent dirt accumulating. Specifications 478,360 and 529,735 are referred to.