Patent GB-935342-A (GB)
Title: Improvements in and relating to planetary rolling mills
IPC: B21B13/20
Filed: 1960-03-08
Abstract: 935,342. Rolling. T. SENDZIMIR. March 8, 1960, No. 8111/60. Class 83 (4). In a rolling mill for making heavy single pass reductions on flat products a driven backing roll drives a smaller working planetary roll by friction at the common generant while a secondary drive exerts forces on the same working roll which are normal to its axis and not passing through the generant, the secondary drive acting at least during the engagement of the roll with the work. Cast or rolled slab, e.g. 1# in. thick is reduced, e.g. to 0.08 in. thickness by planetary rolls 3, 4 backed and driven by rolls 1, 2 respectively. The work 8 may be fed by rollers, travelling gripping shoes or fluid pressure thrust means. The planetary rolls 3, 4 are retained in slotted apertures in rings 14, 15 and 16, 17 which are geared together for synchronizing the rolls 3, 4, the apertures permitting forward precession of the rolls relative to the rings during engagement with the work. Cross-shafts 18, 21 may be driven independently by a motor 29 or may be driven from a combined drive acting through a differential housed in a frame work 30, Fig. 4. The constant speed main drive for the backing rolls acts through gearing 33, 34, 39 on a ring-gear 40 of the differential, while a lowspeed is imparted to a pinionshaft 48, Fig. 7, meshing with planetary gears 43, 44, 45 mounted in a spider 46 on a stub shaft 47. The pinion shaft 48 is driven by a variable-speed motor so that the speed can be gradually increased as the working rolls wear or are dressed. The drive is transmitted from the stub-shaft 47 through further gearing to cross-shafts such as 18, 21, to impart a force acting at the axis of the work rolls. The force acting on the rolls assists the feed of the slab into the mill and, if desired, the feeding action may be increased by increasing the forward precession of the rolls by braking the working rolls or by increasing the retaining ring drive relative to the main drive for the backing rolls, sufficient to render the mill self-feeding. In a modification which increases the leverage advantage on the working rolls by applying the secondary driving force at or substantially at the common generant between the working roll and the slab. A forward force is applied by engaging toothed portions 62, 65 of the rolls 60, 64 with adjustable stationary racks 63, 66, Fig. 9. Correct initial engagement with the racks is ensured by freely-mounted ring-gears 69, 70 and also by providing thinner teeth 71 at entry to the racks. The rolls 60, 61 are mounted in retaining rings 67, 68. Precession is permitted by play between the gear teeth. In a further embodiment, Fig. 11, driven chains 76, 86 engaging sprockets on the working rolls provide the secondary drive. Further chains 81, 90 retain the rolls while ring-gears 69, 70 synchronize the rolls. In another embodiment where two pairs of work rolls simultaneously contact the workpiece precession of the work rolls in the retaining rings is prevented thus forcing the retaining ring forward at increased speed and imposing a drag force at the axis of the following work roll. Specification 655,190 is referred to.