|
(11) | EP 0 145 044 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
|
|
|
|
|||||||||||||||||||||||||||
| (54) | Two-high reversible cogging mill |
| (57) The present invention is embodied with a two-high reversible cogging mill (10) which
is able to roll in two directions and comprises a rolling stand (33) with two rolling
rolls (11-12), reduction gear means (22) and motor means (25), and which is positioned
so as to cooperate with roller conveyors (27) located upstream andior downstream,
and in which (10) the rolling stand (33) with its two rolls (11-12) can take up two
different positions by rotation, one of such positions lying at 180' to the other
position and the rotation taking place in relation to an axis (34) parallel to the
axes of the rolling rolls (11-12). |
[0001] This invention concerns a two-high reversible cogging mill. To be more exact, the invention concerns a cogging mill in which the set of rolls consists of two rolls and in which the to-and-fro passes of the rolled section are obtained by rotating the whole rolling stand by 180° about the generating line of contact between the rolls.
[0002] The entraining of a rolled section in the one direction and the other direction in the one position and the other position of the stand is obtained in this way without changing the direction of rotation of the motor, transmission and individual rolls. This corresponds respectively t.o passes of a bar in both rolling directions along the rolling axis.
[0003] The known art comprises some solutions intended to improve the functional nature or the versatility of rolling mills, but such known solutions differ from the present invention as regards their purposes and embodiments.
[0004] FR-A-2.257.360 concerns a rolling stand in which the rolling stresses are absorbed at. least partially by a stiffening ring, which is positioned outside the rolls and can cooperate with a rolling roll directly. No operating method of a type related to the present invention is disclosed, and this cited FR patent includes working rolls of which the positions are stationary, with only the outer zone rotating, this being a situation which does not permit reversible rolling.
[0005] FR-A-2.289.256 discloses a solution with a seesawing rolling stand, which can rotate about an axis parallel to the rolling axis. The purpose of this is to enable work to be carried on with horizontal or upright rolls. The method of working is therefore wholly different from that of the rolling mill of the present invention.
[0006] FR-A-L180.375 too discloses an embodiment with a rolling stand able to rotate about an axis parallel to the rolling axis and thus enables the rolls to operate in a horizontal or upright position, but such rotation takes place on a plane perpendicular to the feed of the rolled products.
[0007] Three-high rolling mills are known which have oscillatable surfaces upstream and/or downstream from the rolling stand. Such oscillatable surfaces serve to raise or lower the rolled section for its various passes.
[0008] With these surfaces in their lowered position the rolled section carries out. a pass in this way in a first direction between the lower and middle rolls and then carries out a pass in the reverse direction between the middle and upper rolls with the surfaces in their raised position.
[0009] According to this embodiment it is not necessary to reverse the movement of the rolls and an alternating-current motor can be used which always transmits motion in the same direction to the rolls.
[0010] This embodiment entails the considerable drawback of having a heavy and bulky rolling stand. This is due mainly to the fact that three rolls are required to obtain such to-and-fro passes, and, furthermore, oscillatable surfaces of great sizes are necessary.
[0011] In particular, such oscillatable surfaces are very bulky transversely to the rolling axis, namely parallel to the axes of the rolls. This is due to the fact that the rolled section is displaced on the oscillatable surfaces in a horizontal direction during its various passes so as to obtain the required passes within the various grooves with which the rolls of the rolling stand are provided.
[0012] Such displacement in a direction axial to the rolls and perpendicular to the rolling axis is obtained with guides which may be of a movable or static type. These guides act on the rolled section and move it from time to time to a position corresponding to the required groove.
[0013] Drive means are therefore necessary to displace not only the oscillatable surfaces but also such guides.
[0014] Another known embodiment has a rolling stand which is also formed with three rolls and which can be raised or lowered in relation to the level of the roller conveyors on which the rolled section runs. In this way there is no need of oscillatable surfaces upstream and downstream from the rolling stand.
[0015] However, this embodiment entails the very serious drawback of requiring drive means to raise and lower the whole rolling stand. As such a stand has a considerable weight, drive means of noteworthy power and great vertical bulk are required to move it.
[0016] Moreover, the foundations which this type of stand, also called a "jumping stand", needs are of necessity very heavy and costly.
[0017] Another known embodiment envisages the employment of a two-high stand with a direct-current motor that makes reversal of motion possible.
[0018] In this embodiment the rolling stand is simplified as compared to the preceding embodiments and has only two rolls, but the drive means comprise a direct-current motor and are very expensive and also more complex than drive means which have a corresponding alternating-current motor.
[0019] This embodiment too envisages stationary surfaces having rollers and being of a width equal to the axial length of the rolling rolls in the direction axial to the rolls; it also envisages guides able to displace the rolled section into the various grooves of the rolls.
[0020] Lastly, another known embodiment envisages the use of an alternating-current motor and a reduction gear unit equipped with a kinematic mechanism to reverse the motion. For example, this can be obtained by means of a clutch-brake and an appropriate kinematic reversing mechanism.
[0021] The problems of this type of device are its considerable bulk, due especially to the great size of the clutch-brake unit required, and the wear of its parts and the great inertia problems entailed with the employment of large bodies rotating alternately in two directions.
[0022] According to the present invention the drawbacks and shortcomings detailed above and relative to the known embodiments are overcome through the fact that the present invention envisages that the whole rolling stand is rotated by 180° between two successive passes of the rolled section. Such rotation may concern the stand of rolls alone or also the reduction gear unit and possibly the motor too.
[0023] According to the invention the motor always rotates in the same direction and, in a preferred embodiment, is an alternating-current motor.
[0024] If the direction of rotation of the individual rolls remains the same, then the overturning of the stand by 180° entails the reversal of the direction of the pass of the rolled section between such rolls.
[0025] In fact, according to the invention the direction of the peripheral linear speed of the two rolls at their point of contact is reversed with every inversion of the position of the stand.
[0026] Rotation of the stand can be obtained, for instance, by supporting the stand itself within a substantially cylindrical framework resting on rollers. The framework can be driven by a low-powered motor, which can be of a direct-current type, for example, with an encoder. Such motors are commonly used in the present state of the art.
[0027] The framework can also be moved by means of levers or hydraulic actuators, for instance, or other means.
[0028] As an alternative, it would be possible to use a motor with a reversing gear or hydraulic cylinders or hydraulically operated screw-threaded shaft or other equivalent means.
[0029] The device of the invention offers the following advantages:
- a considerable reduction of the weights and overall sizes owing to the employment of only two rolls instead of three and to the absence of movable surfaces;
- the ability to use roller conveyors of a small width, that is, a small extent in a direction axial to the rolls, for it is possible to displace the whole stand axially;
- the ability to use an alternating-current motor to drive the rolls since it is not necessary to reverse their direction of rotation;
- the ability to provide light foundations;
- simplicity of drive and control;
- ease of maintenance.
[0030] The present invention is therefore embodied with a two-high reversible cogging mill which is able to roll in two directions and comprises a rolling stand with two rolling rolls, reduction gear means and motor means, and which is positioned so as to cooperate with roller conveyors located upstream and/or downstream,the rolling stand with its two rolls being able to take up two different positions by rotation,the mill being characterized by the fact that one of such positions lies at 180° to the other position and that rotation takes place in relation to an axis parallel to the axes of the rolling rolls.
[0031] We shall describe hereinafter, as a non-restrictive example, a preferred embodiment of the invention with the help of the attached figures, in which:
Fig.1 gives a three-dimensional view of a cogging mill according to the invention;
Figs.2 give diagrams of the two working positions;
Figs.3 and 4 show two partially cutaway views of the mill, respectively a section crosswise to the rolls and a plan view of the mill;
Figs.5 and 6 are respectively a side view and a plan view of a variant of the invention.
[0032] In the figures a rolling mill 10 has two rolls 11 and 12 supported in a known manner by housings 13 and 14 respectively.
[0033] Means to adjust the distance between centres of the rolls are known in the art and there is no need to dwell on them as such adjustment can be carried out in any known manner.
[0034] A rolling stand 33 thus formed is enclosed within a casing 15 having a substantially cylindrical shape. Such casing 15 can consist of an open framework or, as in the example shown, of a fully closed structure which encloses rolls, housings and accessory means such as lead-in guides 32 for a rolled section 31.
[0035] The casing 15 is rotatably supported on a base 18 by means of rollers 16 which cooperate with rolling paths 17.
[0036] In this example the casing 15 is held axially firmly to the base 18 with abutments 118 against which the front and rear edges of the casing 15 can slide, but it is possible to visualise equivalent means of any nature to obtain an axial engagement of the stand 15 to the base 18.
[0037] The base 18 can run on guide means, or guides, 19 which can be embodied in any known way. For instance, such guides can permit sliding and have a flat profile or a V-shaped profile or be dovetailed; or else the guides can be of a type employing rolling or of another known type.
[0038] The base 18 is visualised as being able to slide axially to the rolls 11-12 so that it can enable the whole rolling stand 33 with the casing 15 to move axially for the passes of a rolled section 31 through the various gauges.
[0039] In fact, in the embodiment shown the rolled section 31 runs along a roller conveyor 27 lying always in the same position and is guided by static manipulators 28 along the rolling axis.
[0040] In the embodiment shown it has been thought preferable to make the whole stand 33 movable since in this way it is possible to employ a roller conveyor 27 having a modest width which is enough for the passes of the rolled section 31.
[0041] In the example shown the movement of the base 18 is obtained by means of a rack 20 cooperating with a pinion 121 of a motor 21.
[0042] Such motor 21 can work with direct current, for instance, and with an encoder control to determine the exact position of the base 18.
[0043] As an alternative it is possible to employ any equivalent drive system known in the art, such as hydraulic jacks, for instance, or other equivalent means.
[0044] The figure also shows a reduction gear unit 22, which is epicyclic in this case, with pinions 23. The reduction gear unit 22 rotates here en bloc with the casing 15 whenever the position of the stand 33 is inverted.
[0046] The reduction gear unit 22 takes its motion from a motor 25 through a telescopic shaft 26, which in the example shown is embodied with a grooved profile but could also have a sliding coupling with a feather or be of another type.
[0047] According to a variant it is also possible for the motor 25 to be solidly fixed to the base 18 and thus to be able to move with the same 18 by sliding on the guides 19; the base 18 and guides 19 will have to have, of course, a suitable lengthwise development.
[0048] In another variant which is not shown here it is possible to envisage the reduction gear unit 22 as being immovable in an axial direction and the shafts 24 as being embodied in a telescopic form according to any known method.
[0049] A circular rack 29 is included on the casing 15 and cooperates with a pinion 130 of a motor 30. In the embodiment shown the motor 30 is a direct-current motor with an encoder to set the exact angular position of the casing 15 and therefore of the rolls 11-12.
[0050] As an alternative the casing 15 can be rotated by means of actuators of various kinds, such as screw-threaded shaft actuators operated hydraulically or by electricity, pneumatic or oleodynamic actuators or other equivalent actuator means.
[0051] Clamping means, which are not shown here, are provided to clamp the casing 15 in its two angular working positions.
[0052] In the first position shown (Fig.2a) the roll 11 is above and the roll 12 is below, whereas in the second position (Fig.2b) the rolls 11-12 and the stand 33 have been overturned by 1800 in relation to Fig.2a. Such overturning of the stand 33 is obtained by the motor 30.
[0053] As can be seen in Figs.2, which show the directing principle of the invention diagrammatically, each roll 11-12 always rotates in the same direction. In the figures the roll 11 rotates anti-clockwise, whereas the roll 12 rotates clockwise.
[0054] In Fig.2a the rolled section 31 runs from left to right in the direction shown with the arrow.
[0055] When the first pass of the rolled section 31 through the rolls 11-12 has been carried out, the whole stand 33 is overturned by 180°, by the motor 30 in this example, about the axis 34 of rotation of the stand 33 and takes up the configuration of Fig.2b.
[0056] The roll 11 is now in the lower position and the roll 12 is in the higher position. As can be seen in the figure, the direction of rotation of each roll has not changed, and the roll 12 still rotates clockwise while the roll 11 still rotates anti-clockwise.
[0057] What has changed in the passage from one configuration to the other is the direction of the running of the rolled section 31, which in the position of Fig.2b runs from right to left, as shown with the arrow.
[0058] Thus it is possible to carry out a series of passes, with the stand 33 alternately in one configuration or the other and therefore with the rolled section 31 running in one direction or the other respectively.
[0059] According to the embodiment of Fig.1 it is also possible to carry out passes through the various gauges comprised between the rolls 11-12 by displacing the whole stand 33 axially.. In this way the rolled section 31 is always kept running in the same spatial position along the roller conveyor 27,being aligned by the manipulators 28.
[0061] According to a variant which is not shown here it is possible to envisage the whole stand 33 together with the casing 15 as being supported on a base 18 which is stationary instead of being able to slide axially.
[0062] In such a case roller conveyors 27 will be provided which have a great enough width, in a horizontal direction perpendicular to the rolling axis, to enable the rolled section 31 to be displaced from one gauge to another of the various gauges available between the rolls 11-12 during its successive passes. Such displacement is performed by the manipulators 28, the ability to move of which will be adapted to suit the extent of the displacement of the rolled section 31.
[0063] In another variant which is not shown here it is possible to provide a roller conveyor 27 having a modest width great enough to accommodate the passes of the rolled section 31, and to displace such roller conveyor 27 in the direction of the axes of the rolling rolls 11-12.
[0064] For instance,the roller conveyors 27 will have at their ends solidly fixed manipulators 28 to position the rolled section 31 correctly.
[0065] In such a case, of course, it will not be necessary to provide the guides 19 nor the actuator means 21, and also the motor 25 can be connected to the reduction gear unit 22 with a rigid shaft.
[0066] In a variant shown in Figs. 5 and 6 a stationary reduction gear unit 22 with pinions 23 is shown. The outputs of motion of the pinions 23 are arranged with the axes of motion on the same plane, which is horizontal in this case.
[0067] The shafts and universal joints 24 in the embodiment of Figs.5 and 6 are envisaged as having a length such that they can transmit suitably the motion from the pinions 23 thus arranged to the rolls 11-12 of the stand 33.
[0068] In this way the rotation of the stand 33 and casing 15 by 180° merely inverts the vertical angular position of the two shafts and joints 24, which leave the pinions 23 at the same height and are directed, respectively, one to the upper roll 11 and the other to the lower roll 12.
[0069] With such an arrangement it is possible to keep the reduction gear unit 22 and pinions 23 stationary instead of being rotated, the stand 33 alone within the casing 15 being rotated.
[0070] In this case the drive for rotation of the stand 33 is obtained with an electric motor 30, the pinion 130 of which meshes with the circular rack 29.
[0071] The embodiment of Figs.5 and 6 shows protruding rolling paths 17 with which flanged rollers 16 cooperate. In this way the sliding of the stand 33 along the rolling axis 34 is obviated.
[0072] In this example the base 18 is stationary. For the sake of simplicity neither the roller conveyors 27 nor the manipulators 28 are shown.
[0073] With such roller conveyors 27 and manipulators 28 it is possible to adopt one or another of the embodiments described earlier in which the base 18 is stationary and which are not - shown.
[0074] As an alternative the base 18 can be visualised as being able to slide in one of the embodiments shown in the previous figures, the shafts 24 being telescopic or cooperating with telescopic shafts in correspondence with the outputs of the pinions 23.
[0075] We have described here some preferred embodiments of the invention but many variants are possible without departing from the scope of the invention itself.
[0076] For instance, it is possible to conform the casing 15 otherwise than in the figures, provided that it is equipped with suitable means for rotation.
[0077] For example, the casing 15 can be envisaged as being supported otherwise than in the figures and as being driven, both axially and in the direction of its rotation, by actuator means of a type different from those shown, which in the figures consist of the motor 21 for axial movement and motor 30 for rotation.
[0078] For instance, actuation of a hydraulic or pneumatic type or by a worm-screw acting on a rack or by gears or other means can be visualised.
[0079] It is also possible to provide the rolls 11-12 with any required conformation suited to the type of rolled section 31 to be made.
[0080] According to the invention it is possible to employ a reduction gear unit 22 other than the epicyclic type shown and also to adopt guides 19 of any type and conformation.
INDEX
[0081]
10 - rolling mill
11 - roll
12 - roll
13 - housing
14 - housing
15 - casing
16 - rollers
17 - rolling paths
18 - base
118 - abutments
19 - guides
20 - rack
21 - motor
121 - pinion
22 - reduction gear unit
23 - pinion unit
24 - extension shafts and universal joints
25 - motor
26 - telescopic shaft
27 - roller conveyor
28 - manipulators
29 - circular rack
30 - motor
130 - pinion
31 - rolled section
32 - lead-in guides for rolled section
33 - rolling stand
34 - axis of rotation of stand.
1 - Two-high reversible cogging mill (10) which is able to roll in two directions
and comprises a rolling stand (33) with two rolling rolls (11-12), reduction gear
means (22) and motor means (25), and which is positioned so as to cooperate with roller
conveyors (27) located upstream and/or downstream, the rolling stand (33) with its
two rolls (11-12) being able to take up two different positions by rotation, the mill
(10) being characterized by the fact that one of such positions lies at 180° to the
other position and that rotation takes place in relation to an axis (34) parallel
to the axes of the rolling rolls (11-12).
2 - Two-high reversible cogging mill (10) as claimed in Claim 1, in which the axis
of rotation (34) of the stand (33) is intermediate between the axes of the rolls (11-12).
3 - Two-high reversible cogging mill (10) as claimed in Claim 1 or 2, in which at
least the stand (33) is solidly fixed to a casing or frame (15) rotatably supported
(16-17) and having means (30-130-29) to actuate rotation and clamping means.
4 - Two-high reversible cogging mill (10) as claimed in any claim hereinbefore, in
which at least the stand (33) can move axially to the rolls (11-12) so as to bring
a rolled section (31) within the various gauges of the rolls (11-12).
5 - Two-high reversible cogging mill (10) as claimed in Claims 1 and 4, in which the
casing (15) is solidly fixed (118) axially (34) to a slider base (18) able to slide
on guide means (19) and provided with drive means (21-20).
6 - Two-high reversible cogging mill (10) as claimed in any claim hereinbefore, in
which the reduction gear means (22) are at least able to rotate together with the
stand (33).
7 - Two-high reversible cogging mill (10) as claimed in any claim hereinbefore, in
which the reduction gear means (22) can move at least axially.
8 - Two-high reversible cogging mill (10) as claimed in any of Claims 1 to 5 inclusive,
in which the reduction gear means (22) are stationary.
9 - Two-high reversible cogging mill (10) as claimed in any of Claims I to 7 inclusive,
in which the motor means (25) are at least able to move rotatably together with the
stand (33).
10 - Two-high reversible cogging mill (10) as claimed in any of Claims 1 to 7 inclusive,
in which the motor means (25) are at least able to move axially.
11 - Two-high reversible cogging mill (10) as claimed in any of Claims I to 8 inclusive,
in which the motor means (25) are stationary.
12 - Two-high reversible cogging mill (10) as claimed in any claim hereinbefore,which
comprises telescopic extension shafts (24).
13 - Two-high reversible cogging mill (10) as claimed in any claim hereinbefore,which
comprises at least one telescopic shaft (26).
14 - Two-high reversible cogging mill (10) as claimed in any claim hereinbefore,which
comprises stationary roller conveyors (27) upstream and/or downstream.
15 - Two-high reversible cogging mill (10) as claimed in any of Claims 1, 2 or 3,
in which the stand (33) is stationary axially (34).
16 - Two-high reversible cogging mill (10) as claimed in any claim hereinbefore, in
which the roller conveyors (27) can be moved parallel to the axes of the rolls (11-12).
17 - Two-high reversible cogging mill (10) as claimed in any claim hereinbefore, in
which the reduction gear means (22) comprise at least epicyclic reduction gears.
18 - Two-high reversible cogging mill (10) as claimed in any claim hereinbefore, in
which the motor means (25) comprise at n least one alternating-current motor.
19 - Two-high reversible cogging mill (10) as claimed in any claim hereinbefore, in
which the pinions (23) are stationary and have their axes defining a plane substantially
at right angles to the plane determined by the axes of the rolls (11-12) in one or
the other of the working positions of the stand (33), the extension shafts (24) being
positioned awry in such working positions (Figs.5 and 6).