Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B31/00—Rolling stand structures; Mounting, adjusting, or interchanging rolls, roll mountings, or stand frames
  • B21B31/16—Adjusting or positioning rolls
  • B21B31/18—Adjusting or positioning rolls by moving rolls axially
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B2269/00—Roll bending or shifting
  • B21B2269/12—Axial shifting the rolls
  • B21B2269/14—Work rolls

Definitions

• the invention refers to a device and method for the controlled shifting of the rolls of a rolling stand, particularly of the working rolls (WR) in a four- or six- high stand.
• the working rolls are advantageously bevelled at one end and are shifted anti-symmetrically one with respect to the other, to control the drop in thickness at the edges of the plane rolled product (edge drop) .
• the state of the art includes a six-high rolling stand, wherein, to control the planarity of plane rolled products, both the working rolls and the intermediate rolls are associated with a shifting device.
• This device however, has the disadvantage that it cannot completely and effectively compensate the edge drop of the rolled product, and requires a particularly long shifting of the rolls .
• Conventional six-high stands are equipped with shifting on the intermediate rolls, so as to increase the ability to control the deformation, under the rolling load, of the rolls of the stand and consequently the profile of the rolled strip and its planarity.
• some constructors have adopted solutions which provide particular configurations and mechanisms on the working rolls.
• working rolls with a circular groove made in correspondence with one end, to increase the flexibility of the cylindrical surface in that zone.
• Such working rolls however have to be positioned axially in such a manner that said more flexible zone is in correspondence with the edge of the strip and can thus control the shape of the strip at the edges (compensation of the so-called edge drop) .
• the axial travel C of each of the rolls varies with respect to the fixed housings of the rolling stand from a zero value to a maximum value and vice versa, as shown in Fig. 3.
• the initial position, or zero position (Pos. 0), in which the chocks G of the two working rolls, upper WRS and lower WRI, are substantially aligned on vertical planes passing through the center line of the relative housings S (Fig. 4) corresponds to the position of the working rolls able to roll a strip with a maximum width Wmax.
• the working rolls WRS and WRI can work a strip with a minimum width Wmin (Fig. 5) , each working roll WRS and WRI is shifted by a travel C. Therefore, as can be seen in Figs. 4 and 5, the maximum relative shifting between the chocks of WRS and WRI is equal to 2C and hence the overall bulk of the stand is also high. Consequently the mechanical solutions of the assemblies which shift the rolls are also much more complex.
• the present Applicant has devised, planned and perfected the device according to the invention to overcome the shortcomings described above, and to improve known devices.
• One purpose of the invention is to achieve a device and a method which allow to obtain long shifting of the rolls of a rolling stand, in particular of the working rolls WR, to control in optimum fashion the drop in thickness at the edges of the rolled product, which may consist of a strip or similar, and yet maintain, at the same time, an extremely compact shifting system.
• the concept provides that the profile of the strip at the edges is controlled by means of a tapered lateral part of the working roll and a suitable axial positioning of one working roll with respect to the other, starting from an initial position or zero position (Pos. 0) in which the chocks of both working rolls are substantially aligned on vertical planes passing through the center line of the housings of the rolling stand. In this zero position the working rolls are in a median position between the two extreme positions corresponding to the maximum width (Wmax) and respectively the minimum width (Wmin) of the strip to be rolled.
• the solution according to the invention allows to achieve a very compact shifting device (in spite of the high travels C of each working roll) .
• the value of the overall travel C is necessarily rather high (in the range of 400-500 mm) , and therefore it is necessary, from the construction point of view, to define the travel of the chocks of the working rolls, upper and lower, starting from the alignment with the latter in the zero position (Pos.0).
• the most favorable Pos .0 is at half the travel of the working rolls (Fig. 6) , so that the travel of each of the working rolls, and hence of the corresponding chocks, both in one direction and the other with respect to Pos.0, is equal to half the travel C, that is, in the range of 200-250 mm (Figs. 7 and 8) .
• the maximum relative shifting of the chocks of the upper and lower working rolls is therefore equal to C.
• chocks of each roll are also advantageously associated with the actuators included to achieve the positive and negative bending ("in” and "out") of the working rolls .
• Fig. 1 is a schematic part view of a state-of-the-art rolling stand in a first working position
• Fig. 2 is a schematic part view of the rolling stand in Fig. 1 (state-of-the-art) in a second working position;
• Fig. 3 is a schematization of the limit positions of the working rolls of the stand in Fig. 1 (state-of-the- art) ;
• Fig. 4 is a schematic part view of a state-of-the-art rolling stand, with the working rolls in the initial position (Pos.O), corresponding to the maximum width of the rolled product (Wmax) ;
• Fig. 5 is a schematic part view of the rolling stand in Fig. 4 (state-of-the-art) , with the working rolls in a position corresponding to the minimum width of the rolled product (Wmin) ;
• Fig. 6 is a schematic part view of a rolling stand wherein a device according to the invention has been assembled, with the working rolls in the intermediate position (Pos.O);
• Fig. 7 is a schematic part view of the rolling stand in Fig. 6, with the working rolls in a position corresponding to the maximum width of the rolled product (Pos. Max)
• Fig. 8 is a schematic part view of the rolling stand in Fig. 6, with the working rolls in a position corresponding to the minimum width of the rolled product (Pos. Min) ;
• Fig. 9 is an enlarged detail of " Fig. 6;
• Fig. 10 is a view from above, part and sectioned, of the rolling stand in Fig. 6; Fig. 11 is an enlarged detail of the device in Fig. 10. DETAILED DESCRIPTION OF PREFERRED EMBODIMENT
• a device 10 according to the invention is shown assembled on a rolling stand 11 comprising a pair of working rolls 12a, 12b, having axes of rotation Xa and Xb.
• the plane product 13 to be rolled consisting for example of steel strip, is able to pass between the working rolls 12a, 12b.
• Two corresponding rolls 15a, 15b which can be back-up or intermediate rolls, according to whether the rolling stand 11 is four-high or six-high, are provided associated with the two working rolls 12a, 12b.
• the device 10 is associated with both the working rolls 12a, 12b to selectively shift them axially, that is perpendicularly to the median rolling axis Y.
• the working rolls 12a and 12b are able to be shifted, one independently of the other, and each with a determined travel C.
• the maximum travel of the two working rolls 12a and 12b goes from the position shown in Fig. 7 (Pos. Max), wherein the width of the rolled product 13 is at its maximum
• the upper working roll 12a has a circular bevel or taper
• the initial position, or zero position, (Pos.O) of the device 10 corresponds to the position wherein the strip 13 has an average width (Wmed) between the maximum width (Wmax) and the minimum width (Wmin) .
• the device 10 comprises, for each working roll 12a and 12b, a pair of cylindrical actuators 20 (Fig. 10) which can be activated simultaneously. It must be pointed out that, to simplify the drawing, in Fog. 10 only the part of the device 10 associated with the upper working roll 12a is shown, while the other part of the device, that is, the part associated with the lower working roll 12b, is the same as the one shown.
• the actuators 20 are arranged on the same motor side (on the left in Fig. 10) and are assembled on a supporting frame 22, attached to a housing 23 of the rolling stand 11.
• the actuators 20 are able to shift, simultaneously and parallel to the axis Wa of the working rolls 12a, a pair of movable blocks 24 which are assembled on a housing 23 of the rolling stand 11 and are connected together by a connection rod 30.
• the movable blocks 24 are guided on prismatic guides 25 attached in the housings 23.
• the motor side chock 26 (on the left in Fig. 10) is provided with shoulders 31, arranged transverse to the axis Xa; the corresponding movable block 24 is able to cooperate with the sides of the shoulders 31, in order to shift the working roll 12a.
• the shifting of the working roll 12a towards the operator side is performed by a direct thrust of the movable block 24 on the left-hand sides of the shoulders 31.
• a first rolling element 40 substantially barrel-shaped, is assembled on the movable block 24, in correspondence with each shoulder 31; in the working position said element 40 is in contact with the. corresponding left side of the shoulder 31.
• the shifting of the working roll 12a towards the motor side is performed by a pair of hook-type levers 28, each of which pivots on a pin 29 of the movable block 24 and oscillates between an inactive position (un-hooked from the corresponding shoulder 31) and a working position (hooked to the shoulder 31) , shown by a line of dashes in Fig. 10.
• Each lever 28, in correspondence with its terminal hook 27, is provided with a second rolling element 41, also barrel-shaped, which is able to cooperate with the corresponding right-hand side of the shoulder 31 of the chock 26, when the lever 28 is in the working position.
• the lever 28 is rotated by means of a pair of hydraulic cylinders 32 assembled on the movable block 24 and able to be activated simultaneously.
• the levers 28 are closed when the hydraulic cylinders 32 are in the contracted position, while with the hydraulic cylinders 32 in the extended position the levers 28 are opened.
• the hydraulic cylinders 32 also act on two supporting elements 33 (Figs. 10 and 11) axially sliding on the movable block 24 and guided on horizontal platelets 35.
• the supporting elements 33 in the extended position of the hydraulic cylinders 32, are able to support a spindle- support element (called “coupling ring") 36, arranged on the command side of the relative spindle 37 which connects the working roll 12a to the motor assembly, which is not shown in the drawings . Therefore, the hydraulic cylinders 32, in the extended position, are able both to open the hook-type lever 28 and also, at the same time, to support the element 36 (change position of the working roll 12a) , while in the contracted position, are able to close the hook-type lever 28 on the chock 26 and to simultaneously release the element 36 (working position) .
• a spindle- support element called "coupling ring”
• the supporting elements 33 consist of a saddle, for example formed by the platelets 35, which is able to move with respect to the movable block 24 to selectively arrange itself below the element 36, on the command of the hydraulic cylinders 32.
• the contemporary movements obtained simply by driving the hydraulic cylinders 32, of the closing/opening of the hook- type levers 28 and the opening/closing of the spindle- support elements 36, not only . simplify the mechanical solution but also shorten the sequence of the roll change, and make it more reliable.
• the movable blocks 24 have the same shifting movements as the chocks 26 of the corresponding working roll 12a, 12b, therefore the hydraulic jacks (not shown in the drawings) , which are assembled on the movable blocks 24 and are included to bend the rolls, always act on the same point of the chock 26.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Control Of Metal Rolling (AREA)
• Shafts, Cranks, Connecting Bars, And Related Bearings (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=11460401

Family Applications (1)

Country Status (3)

Citations (4)

• 2000
  • 2000-09-25 IT IT2000UD000179A patent/IT1315120B1/it active
• 2001
  • 2001-09-24 AU AU2001287975A patent/AU2001287975A1/en not_active Abandoned
  • 2001-09-24 WO PCT/IB2001/001738 patent/WO2002024361A1/en active Application Filing

Patent Citations (4)

Non-Patent Citations (2)

Also Published As

Similar Documents

Legal Events