GB1474933A - Twin-belt continuous casting machine - Google Patents

Abstract

1474933 Continuous casting HAZELETT STRIP-CASTING CORP 11 April 1974 [12 April 1973] 16402/74 Heading B3F In a twin-belt casting machine, in which a casting belt is revolved around a pair of parallel rolls at opposite ends of a carriage frame 38, one of the rolls 22 is hollow and mounted for free rotation on a pair of bearings 56 on a shaft 34 to each end of which is rigidly secured an arm 35 or 36, the two arms being parallel and mounted by pivot mountings on opposite sides of the carriage frame so that they can be swung simultaneously (by coil or air springs with screw jack adjustment or, as shown, fluid cylinders 41, 42) about the mountings to move the roll 22 away from the other roll (20) to tighten the casting belt (14). The apparatus is described for a lower of two carriages and its belt (14), a similar arrangement being used with the upper carriage and belt. The arc (141, Fig. 15, not shown) through which the shaft 34 can be swung, includes a retracted position for belt changing and positions for tightening new and used belts and an intermediate position which lies in a plane through the pivot mountings which is perpendicular to the direction of casting. The stretched length of the casting belt is indicated by a pointer (134, Fig. 10, not shown), mounted on a trunnion-supporting member 50 for the cylinder 42 and co-operating with a scale (135) on the frame 38. The axis of the roll 22 or of its shaft 34 is nearer the axes of the pivot mountings than are the trunnions 48 of the cylinders 41, 42 so that there is a mechanical advantage in applying the tension to the casting belt (14) and a pre-loading thrust is applied to the mountings to eliminate backlash. For steering the steel casting-belt (14) the roll 22 is skewed symmetrically with respect to the frame 38 by a steering lever 76 or 84, Fig. 14, at each end of the roll 22 and secured by a cap 90 or 92 on a shaft 40 or 39 (at a squared section 91 or 93) on an eccentric portion E of which shaft the roll-swinging arm 36 or 35 is pivoted by way of a spherical bushing 72 held by a cap 52. The bushings 72 allow skewing-steering and belttensioning movements to occur simultaneously. The skewing of the roll occurs because the pivot shafts 39, 40 are rotated equally in opposite directions by the levers 76, 84 when the latter are moved by arms 80, 85 mounted on a synchronizing shaft 75 journalled at its ends on the carriage frame 38. A fluid cylinder 99 swings the arm 80 to swing the lever 76 and rotate the shaft 75. The latter swings the arm 85, which operates the lever 84 by way of a link 86. Instead of the cylinder 99, an electrically-, hydraulically- or manually-driven screw jack or a torque motor, may be applied to the shaft 75. Automatic steering may be provided by use of a belt edge sensor or microswitch controlling a valve or switch for actuating the shaft-rotating means. Means 104, Fig. 4, on the frame 38, is coupled to one end of the roll shaft 34 where one of the roll bearings 56 transmits axial thrust between the shaft and the roll 22. The means 104 prevents the shaft 34 from moving axially, to assure that the roll 22 is skewed about a predetermined point, by providing thrust surfaces T, V facing in opposite directions. Thrust blocks 105, 106 mate in sliding engagement with the surfaces T, V and are secured to a spherical bushing 110 mounted on an outrigger 108 of a member 51 supporting a trunnion 48 of the fluid cylinder 41 and secured to plates 67, Fig. 14, of the roll-swinging arm 35. The thrust assembly 104 could be located at either side of the carriage or there could be assemblies at both ends, Fig. 17 (not shown). The bearings 56 on the roll shaft 34 are each mounted on an eccentric sleeve 57 with associated eccentric rings 130 adjustable to various angular positions about the shaft so that each end of the roll 22 can be independently slightly displaced from the shaft axis. The lower belt (14) of the machine may be slightly longer than the upper so that the belts can be nested for storage.