Wire Rolling Mill in Block Form, a So-Called Wire Block With at Least One Driven Line Shaft

The invention relates to a wire rolling mill in block form, a so-called wire block, with at least one driven line shaft from which transverse shafts are branched off via bevel gear transmissions to drive the roll stands and the driving bevel gears are supported on the shaft so as to be freely rotatable and can be selectively coupled to the line shaft by means of clutches. A wire rolling mill of this kind is described in the German Offenlegungsschrift 24 46 905 and offers the advantage that stands or part rolls can be progressively shut down, irrespective of any increase in the rotational speed of the line shaft when larger cross-sections are being rolled, without however, eliminating vibration problems in the region of the roll drives which are not required.

Since natural vibrations cannot be avoided in a multisection drive system of a wire rolling mill in block form of the kind described hereinbefore, there is a risk that shock marks are produced as a result of such natural vibrations in the bearings and on the teeth of stands which are shut down and are therefore stationary. Such shock marks can cause irregular running within the branched drive and this becomes progressively serious the longer a shut-down stand section is exposed to the shock markings resulting from the natural vibrations of the co-rotating drives. This irregular running can be detrimental for the rolled stock.

It is therefore the object of the invention to avoid shock marks on shut-down, branched drives for stand sections or part rolls. The problem is solved in that the driving bevel gears, which are loosely supported on the line shaft, can be driven by slowly rotating supplementary drives each of which comprises a driving wheel which drivingly engages with the associated bevel gear by axial motion and safety means are provided to prevent the axial motion of the slowly rotating driving wheels if the associated clutch for the driving bevel gear is engaged and prevents engagement of the clutch if the slowly rotating driving wheel is drivingly coupled to the bevel gear. This ensures that the bevel gear assembly and the transverse shafts of a stand section or of a pair of part rolls slowly rotate constantly when they are disengaged from the line shaft. It is perfectly feasible for the slowly rotating driving wheels to be also constructed as bevel gears which mesh with the associated bevel gear on the line shaft by means of axial motion. However, it is preferable for each of the slowly rotating driving wheels to be constructed as friction wheels of bevel gear configuration on cantilevered supports, whose drive shafts, extending transversely to the line shaft, can be axially disengaged from the bevel gear against the persistent force.

Mutual blocking of the operations for coupling the slowly rotating driving wheel as well as the clutch is conveniently ensured by the control lever of the clutch and the control lever of the supplementary drive being coupled to each other so that both coupling operations are necessarily performed in opposite senses.

One exemplified embodiment of the invention is illustrated in the accompanying drawing in which:

FIG. 1 shows the two last stand sections of a wire block with their selectively disengageable drives in a longitudinal section through the bearings, otherwise as a front view and

FIG. 2 a slowly rotating supplementary drive to an enlarged scale as a longitudinal section.

The wire block comprises a casing 1 with a line shaft 4 supported therein and driven on the exit side via a back-gear transmission 2 by a variable-speed d.c. motor, not shown. Driving bevel gears 5, 6, in constant mesh with driven bevel gears 7, 8, are supported on the line shaft 4 so as to be freely rotatable. The bevel gears 7, 8 drive transverse shafts 9 and 10, the ends of which support cantilevered top roll sections 11 and 12. The roll sections situated therebelow are mounted on additional transverse shafts, not shown, which are coupled to each other by means of counter-rotating pinions 13 and 14. Corotating clutch sleeves 16, 17 are provided on the line shaft 4 and are slideable by means of hand levers 18, 19 on the line shaft 4 which is provided with splining. Each clutch sleeve 16, 17 is provided with internal teeth, for example 17a, which can be engaged or disengaged with external teeth 6a of the bevel gears 5 or 6. It can be seen that the clutch sleeve 17 is disengaged and the associated bevel gear 6 is uncoupled and the stand section with the roll 12 is shut down. The clutch sleeve 16, on the other hand, is engaged and entrains the bevel gear 5 so that the stand section with the roll 11 is in operation.

Each bevel gear 5 or 6, which is freely rotatable on the line shaft 4, is associated with a supplementary drive 20, 21 with axially adjustable friction wheels 22, 23 of bevel gear configuration. It can be seen that the friction wheel 22, associated with the bevel gear 5, is set in the upward direction while the friction wheel 23 of the supplementary drive 21 is engaged with the conical collar 6b of the bevel gear 6. The supplementary drive 21 therefore enables the uncoupled and freely rotatable bevel gear 6 to rotate slowly. The branched drive 8, 10 and 14 for the roll pair 12, which is actually shut down, being the last stand, therefore also rotates. To ensure alternating actuation of the supplementary drives 20 or 21 by means of the associated clutch sleeves 16 or 17, the control levers 18 or 19 are connected via coupling rods 25 to the control levers 26, 27 of the supplementary drives 20, 21 so that, for example, if the clutch sleeve 16 is engaged the friction wheel 22 is lifted off the conical mating surface 5a of the bevel gear 5 and vice versa can be engaged for frictional contact only if the clutch sleeve is disengaged from the bevel gear which applies to the clutch sleeve 17 and to the friction wheel 23.

FIG. 2 shows the supplementary drive 20 for the bevel gear 5 as an enlarged view and in section but rotated through 90.degree. with respect to the arrangement of the control lever 26. The slowly rotating driving wheel of the supplementary drive 20 is constructed as a friction wheel 22 of bevel gear configuration with a cantilever support disposed on a drive shaft 30 which extends transversely to the line shaft 4. The drive shaft 30 has a splined end 30a which meshes with a bush 31 which is provided with internal teeth and is driven by a hydraulic motor 32. The hydraulic motor is flange mounted on a casing cover 33 which covers a cylindrical casing 34 with a cylindrical external bush 35.

The drive shaft 30 is supported within an axially adjustable bush 36, 37 comprising two parts of which the upper part 37 of the bush supports a collar 37a as an abutment for a compression spring 38 which bears on the casing cover 33. Axial adjustment of the bush 36, 37, which is prevented against co-rotation, and of the drive shaft 30 is performed by an adjustable eccentric 39, associated with an adjusting spindle 40 which is supported tranversely to the adjusting direction of the drive shaft 30 in the casing shell 34 and can be adjusted by the hand lever 26. The collar 37a, which is biased by the force of the spring 38 and is associated with the bush part 37 bears upon the adjusting eccentric 39, so that depending on the position thereof the slowly rotating friction wheel 22 bears drivingly on the conical mating surface 5b of the bevel gear 5 or is in the idling position illustrated in FIG. 2.