GB2137911A

GB2137911A - Universal Rolling Mill Stand with Open Housings, Convertible into a Two-High Stand with Open Housings and Vice Versa

Info

Publication number: GB2137911A
Application number: GB08404812A
Authority: GB
Inventors: Jacques Michaux
Original assignee: Sacilor SA
Current assignee: Sacilor SA
Priority date: 1983-02-25
Filing date: 1984-02-23
Publication date: 1984-10-17
Also published as: ES530622A0; KR840007667A; IT1179996B; SE8401001D0; IT8467180A0; DE3406659A1; GB2137911B; IT8467180A1; IT8453016V0; AU2506484A; SE8401001L; ZA841430B; LU85207A1; GB8404812D0; FR2541600B1; FR2541600A1; ES8501260A1

Abstract

Universal stand with open housings can be horizontally separated into three assemblies: upper (I) and lower (III) which are similar, and a central assembly (II), each assembly being separable vertically into two parts. The two assemblies, upper (I) and lower (III), each consists of two similar caps (1). The central assembly consists of two similar half-parts (2), linked together and each containing two columns (8), surrounded by a half-girdle (17). The stand is prestressed in the horizontal plane by horizontal tie rods 3 and the assemblies, upper (I), central (II), and lower (III) are linked together by four vertical tie-rods (5) under tension. This universal stand can be converted into a two-high stand by replacing the central assembly (II) with a different central assembly (IV) specific to the two-high stand. <IMAGE>

Description

SPECIFICATION Universal Rolling Mill Stand with Open Housings, Convertible into a Two-high Stand with Open Housings and Vice Versa The invention applies to a universal stand and a two-high stand for the rolling by the universal or conventional method of H and I beams, rails, sheet piles, channels, angles, and other similar shapes.

The designation universal stand is applied to a stand that comprises two rolls with horizontal axes and two rollers with vertical axes, and the designation two-high stand applies to a stand that only comprises two rolls with horizontal axes.

Numerous universal stands are known which can be classified in several different categories according to the range of dimensions of the rolled products and whether or not conversion into a two-high housing is possible.

When a stand or rolling mill must be designed for a wide range of shapes and shape dimensions, it becomes indispensable to be able to vary the interaxial distance of the roll chocks thereby allowing the use of rolls of the necessary minimum barrel length, because if such is not the case, the cost of wide rolls become prohibitive for the smallest shapes. With regard to this philosophy, two types of stand constructions are known. The first type uses housings that can be displaced with regard to each other. This first type of stand, which can be found on the old rolling trains of the GREY type, was dismountable in the rolling position. It presents the drawback of bad rigidity because of the high windows and long travel of the screw-down mechanism, of a heavy weight, and of an elevated installation cost.The second type uses transverse beams which also serve to counterbalance the upper roll, allowing a concentric displacement of the chocks according to the desired interaxial distance (Journal, IRON AND STEEL ENGINEER, May 1970, pp. 77-81).

The second type of stand presents the same drawbacks of bad rigidity, high and wide windows, and long travel of the screw-down mechanism.

In designing a stand for the rolling of a narrow range of profile sizes, (for example the medium section rolling mills for beams from 100 to 400 mm, or the heavy section mills for beams from 200 to 600 mm), there is no need for varying the barrel length of the rolls. The width of the stand cannot be extended and the interaxial distance of the chocks remains fixed. This presents the disadvantage of a high cost of the rolls for sections of small sizes.

Increasing the rigidity of the universal stands by designing composite stands with prestressed tie-rods has been tried. These stands, designed for continuous medium size beam rolling mills, are composed essentially of three parts, namely an upper cap comprising the upper half-posts, a girdle piece containing or prepared to receive vertical rollers, and a lower cap comprising the lower half-posts. The three parts are assembled by means of pre-stressed vertical tie-rods. The composite stands present the disadvantage of not allowing for the variation of the barrel length of the rolls, resulting in a high cost of the rolls for small size shapes. The composite stands can be transformed into two-high stands through omission of the girdle and vertical rollers.

There is also known a so-called compact universal stand (U.S. Patent No. 5,802,242), assembled by means of tie-rods without pre stressing, which comprises essentially three parts, namely a central part forming the girdle and the upper and lower cross-heads. This stand also presents the disadvantage of elevated cost of the rolls for small size shapes because it does not allow for the variation of the interaxial distance of the chocks.

There is also known a so-called "housingless compact" universal stand. It is composed of upper and lower chocks, a horizontal girdle piece, and prestressed assembling tie rods in the vertical plane. This stand presents the same drawback of not allowing for variation of the interaxial distance of the chocks, and hence of elevated cost of rolls for small size shapes. Some types of compact stand are not suitable for reversible rolling, because their design does not allow variation of the setting of the rolls to an appropriate value and at sufficient speed between passes.

To remedy the above-mentioned dis advantages of prior art stands, the invention has as its purpose: a universal stand, convertible into a two-high stand and vice-versa suitable for reversible rolling; the possibility of extending the height and the width of the stand by an exactly required value to allow for the rolling of sections within an extended dimensional range, without leading to sacrifices in the cost of the rolls, the rigidity of the stand, and excess weight of the stand when rolling shapes of small sizes; an improved standardization of the stand elements for reducing the initial investment cost and the spare parts for a rolling mill, particularly a combination rolling mill operated with universal or two-high stands or with a combination of both; universal and two-high stands of improved rigidity;; a design of stands, compatible with a rapid changeover of stands in a rolling mill.

According to one aspect of the invention, a universal stand is provided, the stand having open housings and being convertible into a two-high stand and vice versa. The stand is separable horizontally into three assemblies, an upper and a lower assembly, both similar, and a central assembly, each assembly being separable vertically into two parts. Each of the upper and lower assemblies consists of two similar caps.

The central assembly consists of two similar linked-together half-parts, each comprising two posts or columns surrounded by a half-girdle. The stand is prestressed in the vertical plane, the upper, central, and lower assemblies being linked by four vertical tie-rods held under prestressing.

The stand is also prestressed in the horizontal plane, the central half-parts being assembled by means of four horizontal tie-rods held under prestressing.

According to another aspect of the invention, a two-high stand, obtained by conversion of the universal stand, is provided. The upper and lower assemblies are those of the universal stand, the central assembly of the universal stand being replaced by an assembly specific to the two-high stand comprising four open posts or columns linked laterally by means of braces and at the front and back of the stand by half cross beams.

The central assembly is vertically separable in two similar half-parts assembled by means of four horizontal assembling tie-rods. The stand is assembled and prestressed in the vertical plane by means of four vertical tie-rods held under prestressing.

In accordance with other preferred aspects of the invention, a two-high stand is provided, prestressed in the vertical and horizontal planes; prestressing of the stands is made by means of hydraulic jacks and locking by means of nuts after tensioning of the tie-rods; the vertical and horizontal prestressing values are varied to adapt to rigidity of the stand to the variations of rolling the rigidity of the stand to the variations of rolling allowing the release of the prestressing in case of an accident during the rolling.

Further preferred features and advantages of the present invention will be more fully apparent from the following detailed description with reference to the accompanying drawings of the presently preferred embodiments thereof.

In the drawings: Figure 1 is a front view of the universal stand of this invention; Figure 2 is a side view of the universal stand of this invention; Figure 3 is a plane view according to cross section A-A of Figure 1; Figure 4 is a front view of the universal stand of this invention, with two partial cross sections B-B and C-C as indicated in Figure 2; Figure 5a is a top view of one of the caps; Figure 5b is a cross section according to section D-D in Figure 5a; Figure 6 is a front view of the two-high stand of this invention; Figure 7 is a side view of the two-high stand of this invention; and Figure 8 is a plane view according to cross section E-E in Figure 6.

The universal stand of this invention is composed of three assemblies, an upper assembly I, a central assembly II for the universal stand, and a lower assembly Ill, as indicated by the brackets shown in Figure 1. The upper and lower assemblies I and Ill are similar. Each one comprises two symmetrical caps 1 which may be linked together by appropriate means, bolts for example. The central assembly II of the universal stand is composed of two identical central halfparts 2. The central half-parts 2 are linked together by four identical horizontal tie-rods 3, tightened at each of their ends by the nuts 4. The horizontal tie-rods 3 are located within the traversing borings 3' within the girdle half-crossbars 7. On each half-part 2 two superimposed half-crossbars 7 are provided on the encircling girdle at the front of the stand, and two more are superimposed on the back.The upper assembly I, the central assembly II of the universal stand, and the lower assembly Ill are linked by four identical vertical tie-rods 5 tightened by the nuts 6. The vertical tie-rods 5 are located within the aligned traversing borings 5' within the four caps 1 and within the four vertical posts or columns 8. The columns 8 are symmetrical two by two and located within the four girdle half-crossbars 7.

The caps 1 ensure the linking of the columns 8 in the longitudinal and transverse directions of the stand. A cap 1 is located at each end of the corresponding two columns 8, and each comprises a strap 1' that links longitudinally two columns 8 and forms with them the windows 10 of the universal stand. Each cap (Figure 5a) may comprise in addition two horizontal cap halfcrossbars 11, both located on the same side of the cap, on the front or back thereof. The linkage of the caps plays no part with regard to the rigidity of the stand; its only function is to allow the attainment of a platform on which the auxiliary devices of the stand will be mounted.

Each half-crossbar 11 of the cap supports, for example, on its free end at the inside of the stand an assembly plate 1 2 provided with borings 1 3.

The two caps 1 of the same assembly may be assembled, for example, directly on their assembly plates 12 by means of bolts passing through the borings 13 and tightened by means of nuts.

The upper and lower assemblies I and ill support respectively screw-down mechanisms of the horizontal upper roll 14 and of the lower roll 1 5, as well as the counterbalancing devices for both. These mechanisms and devices are symbolically represented in Figure 2 by the reference number 1 6. The drive motors (not shown) of the screw-down mechanisms may be placed, for example, on top of the upper assembly I, and in this case the transmission of the drive command to the setting mechanisms of the lower roll may be accomplished by means of shafts (not shown).

Each central half-part 2 of the universal stand, which may be a one piece casting or may be an assembly of its main constituting elements, comprises mainly two open vertical columns 8 and a half-girdle 17 in the form of a flat lying U.

Each half-girdle 17 which surrounds the middle of two columns 8 supports on each of its vertical faces in front and in back (long branches of the U), on top and beneath of these, a girdle half-crossbar 7 having an end 7' that stretches toward the inside of the stand beyond the columns 8.

The chocks 18 of the horizontal rolls are located between the columns 8 and can be displaced vertically between them. The roller frames 19 of the vertical rollers 20 (Figure 3) are located within the half-girdles 1 7 and can be displaced horizontally within these and between the columns 8. The setting mechanisms of the vertical rollers 20 are supported respectively by the corresponding half-girdles 1 7 and are symbolically represented by the reference number 21 in Figure 3.

The arrangement whereby only the girdle half crossbars 7 extend toward the inside of the stand (Figure 1) beyond the columns 8 with the half girdle 1 7 ending close to the columns leaves within the central assembly II of the universal stand, at the front and the back of the stand, the openings 38 for the passage of the rolled products; (Figure 1 shows the cross section of an H beam as a crosshatched outline).

Each column 8 has on its lower end side, on its front or back side respectively (Figure 2), a foot 22. Height adjustment shims 23, slid between the feet 22 and the structures on which the stand is sitting and secured, allow the adjustment of the horizontal rolling plane 24 of the stand. in relation to the horizontal plane (not shown) of the roller tables upstream and downstream of the stand.

The width of the universal stand can be extended for adaptation to different barrel lengths of the horizontal rolls 14 and 15. The widening of the stand in the transversal direction is carried out by insertion of a cap horizontal spacing piece 25 of proper length between each cap half-crossbar 11 (if such is foreseen) of each cap 1 (i.e. four cap spacing pieces 25). Horizontal girdle spacing pieces 26 of proper length are inserted between the assembling ends 7' of the girdle half-crossbars 7 (i.e. four girdle spacing pieces 26). The possible cap spacing pieces 25 may be provided with horizontal borings in correspondence with the borings 13 (Figure 5b) made in the cap assembly plates 1 2 to allow for the passage of the assembling bolts.Each of the girdle spacing pieces 26 may be provided with a horizontal traversing boring 3' for the passage of the horizontal tie-rods 3, or with a slit allowing them to be fitted upon the horizontal tie-rods 3 without need for removing the latter from any borings to carrying out the widening of the stand.

The resetting of the universal stand to its minimum width is carried out by the removal of respectively the cap and girdle spacing pieces 25 and 26. Each girdle spacing piece 26 will be removed from the above described position and slid over one of the ends of each horizontal tie-rod between the nut 4 of the respective horizontal tie rod and the tightening end 7" of the respective girdle half-crossbars 7. It can be substituted in the latter position by an appropriately shaped piece having an equivalent thickness. This type of procedure allows for the use of tie-rods of constant length and hence allows the use of the same horizontal tie-rods for any given width of the universal stand.

The height of the universal stand can be extended to adapt it to the different working diameters of the horizontal rolls. The extension of the stand in the vertical direction is carried out by insertion of a height spacing piece 27 of proper thickness between the ends of the columns 8 and the caps 1 (i.e. a total of eight height spacing pieces 27). Each of the height spacing pieces 27 is provided with a vertical boring 5' to allow for the passage of a vertical tie-rod 5. According to the invention, the resetting of the universal stand to its minimum height between caps 1 is carried out by removal of the height spacing pieces 27 from the above described position. In this case (Figure 4), it is advantageous to place one height spacing piece 27 (as it is being removed) on each end of each vertical tie-rod 5 between the nut 6 and the cap 1.In the same way as with the girdle spacing pieces 26, the height spacing pieces 27 may be substituted by pieces of proper shape and equivalent thickness between the nuts 6 and the caps 1. This type of procedure allows for the use of the same tie-rods 5 for any given height of the universal stand.

As explained above, the universal stand can be adjusted to intermediate heights and widths respectively by the interposition of height spacing pieces 27 of proper thickness between the columns 8 and the caps 1, and cap spacing pieces 25 and girdle spacing pieces 26 of proper width between, respectively, the caps 1 and the assembling ends 7' of the girdle half-crossbars 7.

In this case, it will be necessary to also place pieces with proper thicknesses and widths, respectively, below the tightening nuts 4 and 6 in order that one may maintain constant lengths of the horizontal and vertical tie-rods. In a preferred variant of the invention, the universal stand is prestressed in both planes, the vertical and the horizontal. Prestressing in the vertical plane is carried out by putting the four vertical tie-rods 5 under tension. In the horizontal plane it is carried out by putting the four horizontal tie-rods 3 under tension. The eight tie-rods put under tension achieve the prestressing of the elements of the stand. After establishing the prestressing at a level greater than the rolling force, the horizontal tie-rods 3 and vertical tie-rods 5 are blocked, respectively, by means of the nuts 4 and 6.The horizontal tie-rods 3 and the vertical tie-rods 5, once they are blocked, act, respectively, as prestressing springs in opposition to the spring of the horizontal girdle constituted by the horizontal girdle half-crossbars 7 under compression and the spring of the vertical columns 8, also under compression.

Each of the vertical assembling and prestressing tie-rods 5 is preferably constituted by three pieces (Figure 4). The two end pieces labelled 5A are identical. They are held in position and remain within the caps 1. The third, the centre piece, labelled 5B, remains permanently in place within the columns 8. Each of the two ends of the centre piece 5B is provided with a female connection head 5C. A male connection head 5D is fastened to each piece 5A of the vertical tierods on the ends next to the columns 8. The function of the female and male heads 5C and 5D is to join and separate parts 5A and 5B of the vertical tie-rods 5.The vertical borings 5' in the caps 1 and in the columns 8 allow for the free elongation of the parts 5A and 5B of the tie-rods.

Hydraulic jacks 28 are mounted on the parts 5A of the tie-rods outside of the caps 1. These hydraulic jacks 28 are used to establish the prestressing of the vertical tie-rods 5. Once the prestressing has been established, the hydraulic jacks 28 may be locked by means of the nuts 6, and the hydraulic pressure in the hydraulic jacks 28 may be released. Also, according to the invention, it is possible to lock by means of the nuts 6 only the hydraulic jacks located on one side of the stand, the hydraulic jacks on the other side remaining locked by the hydraulic pressure. It is also possible to use on this last side hydraulic safety jacks 28', provided for example with a calibrated adjustment valve, for open air venting.

In another variant, this valve may be controlled by an external device activated by the rolling pressure. These safety jacks 28' have as their primary function to avoid the breakage of the rolls in case of excess rolling pressure because of a cobble. A second function is to allow for the separation of the rolls and rollers to protect them against themal shock in case of a stoppage of the bar being rolled between the rolls and rollers as, for example, in case of sudden stops of the motors or failure of the screw-down movements.

In the latter case, the nuts 6 will be screwed in at a certain distance from the hydraulic safety jacks 28' in such a way that they will allow for the release of the prestressing of the vertical tie-rods to avoid ruptures while avoiding a sudden separation of the elements that constitute the stand.

The horizontal assembling and prestressing tierods 3 each consist of only one piece. They are prestressed in the same way as the vertical tierods 5 through the use of the hydraulic jacks 29, similar to the hydraulic jacks 28. Similarly, hydraulic safety jacks 29' may be used in the same way at all the ends of the horizontal tie-rods of a half-girdle 1 7. In this case, the nuts 4 located on this same side will not be locked on the hydraulic jacks 29', but will be screwed in in such a way as to allow for the release of the prestressing and a certain opening of the girdles in the horizontal direction.

One may make the hydraulic feeding of the hydraulic prestressing jacks to be controlled by a continuously measuring system of the rolling forces exerted on the rolls during the rolling process in such a way to adjust the prestressing value to the increase of the rolling forces that may be applied to a rolled product during the rolling. The measurement of the rolling forces may be carried out, for example, by means of strain measuring gauges located between the setting screws and the chocks of the vertical rollers on the one hand, and those of a horizontal rolls on the other. The gauges that measure the rolling forces exerted on the vertical rollers adjust the prestressing in the horizontal direction by increasing or decreasing during the rolling process the hydraulic pressure within the hydraulic jacks 29'.The gauges that measure the rolling forces exerted on the horizontal rolls adjust the prestressing in the vertical direction by increasing or decreasing during the rolling process the hydraulic pressure within the hydraulic jacks 28'.

After disconnecting the hydraulic fluid and the electrical circuits, release of the prestressing of the vertical tie-rods and loosening of the nuts 6, and separation of the tie-rod heads 5D and 5C, the disassembling can be carried out as one wishes by separate removal of the upper caps 1, or by removal of the upper assembly I if the horizontal cap spacing pieces 25 have not been removed. The upper horizontal roll 14 with its chocks can be extracted through the top of the housings, either during the course of the removal of the upper assembly I, in which case it will remain fastened by its suspension elements, or after the removal of the upper pieces. The central assembly II and the lower part lil remain in place for the rest of the dismantlement of the stand.

After having extracted the devices that constitute the guiding system (not shown), the roller frames 19 of the half-girdles 17 are removed through the top. The lower horizontal roll 15 with its chocks is then removed through the top by sliding the chocks through the windows of the columns 8. If the housing is not going to be subjected to transformation operations in width or height, remounting is carried out in inverse order.

Mounting and dismounting may be carried out at the rolling site or, preferably, in a workshop. In the latter case, the stand is moved to the workshop by convenient means, such as an overhead crane or trolley.

The conversion, when necessary, of the universal stand of the invention into the two-high stand of the invention is carried out by replacing the central assembly II of the universal stand by a centre assembly IV (shown by the bracket in Figure 6) specific to two-high stands.

The upper and lower assemblies of the twohigh stand are identical, respectively, to the upper and lower assemblies land Ill of the universal stand. These assemblies may be common to both types of stands and, in fact, are perfectly interchangeable between them. The transformation, when necessary, of the two-high stand into the universal stand is carried out by replacing the centre assembly IV of the two-high stand by a centre assembly II of the universal stand. Given that the assemblies I and Ill of both the universal and the two-high stands are identical, the description of the two-high stand will be limited to a description of the centre assembly IV of the two-high stand.

The centre assembly IV of the two-high stand is composed of four vertical columns 30 (Figure 6). In each column there is a traversing vertical boring 31 (Figure 8) for the passage of the vertical assembling and prestressing tie-rods 5 (represented in the Figures by their axes). The vertical tie-rods 5 can be made, like those of the universal stand, to consist of three parts (not shown). The central parts 5B of the tie-rods 5 of the two-high stand have a length which differs from that of the central parts of the vertical tierods 5 of the universal stand. Half-crossbars 32 are located and fixed at the top and bottom of the columns 30 close to the ends thereof, four on the front and four on the back of the two-high stand, for a total of eight.Horizontal traversing borings are provided within these half-crossbars 32 for the passage of the upper and lower horizontal assembling tie-rods 33 and 33', respectively.

An upper horizontal lateral crosspiece 34 is provided on each outer side of the upper part of each housing (Figure 7). The upper crosspieces 34 have pins 34' at their ends that slide into brackets 35 provided on the columns 30. To this effect, a slit 35' (Figure 6) is provided on each bracket 35 allowing for the placement and removal of the upper crosspieces 34. A lower lateral crosspiece 36 is provided on each outer side of each housing at the lower part of the columns 30. The lower crosspieces 36, each in the form of a U, surround the columns 30 making contact with the lateral faces of the columns 30 and extending over a part of the front faces of the columns where they make contact with the lower horizontal half-crossbars 32. The assembling tierods 33 are slipped into the upper half-crossbars 32 and tightened at their ends by the nuts 37.The assembling tie-rods 33' are slipped into the lower half-crossbars 32 as well as into the two parallel branches of the U formed by the lower crosspieces 36, and tightened at their ends against the lower crosspieces 36 by the nuts 37. The upper crosspieces 34 are locked against the brackets 35 by the nuts 37.

The width of the two-high stand can be extended (Figure 6) as with the universal stand by the insertion of cap spacing pieces 25 between the caps 1 and of horizontal crossbar spacing pieces 26' between the half-crossbars 32 and 32'. The height of the two-high stand can be extended as with the universal stand by insertion of the height spacing pieces 27. Figures 6 and 7 show the configuration of the two-high stand at its minimum height. In this case, the height spacing pieces 27 (or equivalent pieces of the same thickness) are intercalated between the hydraulic jacks 28 and 28' and the caps 1. For the extension of the height of the stand, the height spacing pieces 27 are placed, as with the universal stand, between the caps 1 and the columns 30.Resetting of the stand to its minimum height is carried out, as with the universal stand, by removal of the horizontal cap spacing pieces 25, if such exist, and by displacing the horizontal pieces 26' from their position shown between the half-crosspieces 32 and 32'.

As with the universal stand, one may, for example, place the spacing pieces 26' at the ends of the tie-rods 33 and 33', between, respective, the horizontal half-crossbars 32 and between the lower lateral crosspieces 36 and their tightening nuts 37. This allows for the use of the same horizontal tie-rods for different widths of the twohigh stand. To adapt the two-high stand to intermediate heights and widths, one proceeds in a similar way as with the universal stand.

The two-high stand of the invention is prestressed in the vertical plane as is the universal stand. Given that the prestressing is carried out in exactly the same way and with the same means, a repetition of its description is not necessary.

Similarly, the two-high stand can be prestressed in the horizontal plane in the same way as the universal stand. To this effect, one places hydraulic jacks at the ends of the horizontal tierods 33 and 33', and these hydraulic jacks are locked in the same way by means of nuts. As with the universal stand, one may have the hydraulic feed of the hydraulic prestressing jacks be controlled by a system that measures the rolling forces exerted on the rolls during the rolling.

The mounting and dismantling of the two-high stand is carried out in the same way as with the universal stand; there are however some small differences because of the absence of the vertical roller frames and the presence of the upper crosspieces 34 that must be loosened and removed so that the rolls may be lifted and extracted.

Taking into account such demands as the production programs, the deisgns of rolling mills, and the operating conditions, several advantages are provided by the invention. They bear on the cost of the initial investment for a rolling mill, the range of sizes and the variety of shapes that it allows to be rolled, the tighter tolerances and the smaller thicknesses permissible by the built-in high rigidity of the stand, the operating cost reductions provided by the high standardization of the equipment of the stands, the reduction of the cost of the rolls, and the possibility of quick rolling program changes. The high rigidity of the stands allows, furthermore, the rolling of bars of great length.The possibility of converting universal stands into two-high stands and vice versa and the advanced standardization of their constituting elements allow reduction of the initial investment costs of a rolling mill through reduction of the manufacturing cost of the stands. Furthermore, because of their production in series and because of the advanced interchangeability of the constituting elements of the two types of stands, the number of complete stands that must be acquired and the volume of spare parts that must be provided can be reduced. The possibility of extending the width and height of the stands allows for the rolling of a wide range of sizes and for a wide variety of products on one and the same mill, while up to now it was necessary to specialize the stands or the rolling mills within a narrower range that, after adding up all factors, led to the multiplication of the number of stands and rolling mills. Here also, the invention allows for economies in the investment expenses.

Moreover, the extension possibilities allow for considerable economies in the weight of the rolls and hence in the operating costs of the rolling mills, i.e. lesser initial investment cost of the rolls, lesser roll cost per ton of product made.

The prestressing in both planes of the whoie stand in such a way that a maximum number of stand components is under prestressing, the narrow windows, the achievable minimum height of the windows and, therefore, a minimal travel of the setting screws with regard to the diameter of the horizontal rolls, ensure an extremely high built-in rigidity of the stands of the invention that, furthermore, allow reversing rolling.

The modular construction of the stands with components of relatively low unit weight (of an order of a maximum weight of 36 tons) allows for the installation of the stands and their use in buildings provided with overhead cranes of a relatively low lifting capacity, which in turn leads to considerable economies in the buildings and the necessary overhead cranes.

Claims

1. An open housing universal stand having horizontal rolls and vertical rollers for the rolling of shapes and convertible into a two-high stand having horizontal rolls comprising: horizontally separable upper, central and lower assemblies; said central assembly comprising two half-parts, each including an open housing comprising two columns; a half-girdle in the form of a U lying horizontally on its side and open toward the inside of the stand, said half-girdle surrounding the two columns around their median parts and ending close to the columns near the interior of the stand; two superimposed horizontal girdle halfcrossbars carried on each face of each half-girdle on the front and back of the stand, said halfcrossbars each having an assembling end and a tightening end and extending on either side of said two columns toward the interior of the stand at their assembling ends and toward the exterior of the stand at their tightening ends, the assembling ends of the girdle half-crossbars of each central assembly half-part being juxtaposed when the central assembly is in assembled relation, each pair of juxtaposed half-crossbars having aligned transversed borings therein; a tierod extending through the aligned borings of each pair of juxtaposed crossbars for assembling the central assembly half-parts; and means supported on the tightening ends of the crossbars for tensioning the horizontal tie-rods thereby prestressing in the horizontal plane the components of the central assembly; the upper and lower assemblies each comprising two caps, each cap including a strap for capping and linking the ends of two columns on one side of the stand; and means for joining said upper, central and lower assemblies in assembled relation and for vertically prestressing said stand.

2. A universal stand according to claim 1, wherein said means for tensioning the horizontal tie-rods comprises nuts secured to the ends of the tie-rods and supported on the tightening ends of the girdle half-crossbars.

3. A universal stand according to claim 1, wherein said means for joining said upper, central and lower assemblies and for vertically prestressing said stand comprises: said caps and said columns having aligned vertical borings therein; a plurality of vertical tie-rods, one extending through each group of aligned vertical borings in said caps and columns; and means disposed on the ends of the vertical tie-rods and supported by the caps for tensioning said vertical tie-rods thereby prestressing in the vertical plane the components of the stand therebetween.

4. A universal stand according to claim 3, wherein said means for prestressing said vertical tie-rods comprises a plurality of nuts, one secured to each end of said vertical tie-rods.

5. A universal stand according to claim 3, wherein said means for prestressing said horizontal and vertical tie-rods comprises hydraulic jacks or nuts in combination with mechanical nuts, said mechanical nuts locking said hydraulic jacks or nuts after sufficient tension of the tie-rods is achieved, to permit the slackening of the hydraulic pressure within the hydraulic jacks or nuts after locking.

6. A universal stand according to claim b, further comprising: means for detecting increases in rolling pressures; means for increasing prestressing in said horizontal and vertical planes as a function of increasing rolling pressure, said means for increasing said prestressing comprising said hydraulic jacks or nuts on one side of the stand and on the top or bottom thereof.

7. A universal stand according to claim 6, further comprising means for slackening the hydraulic pressure within the hydraulic nuts or jacks in response to a predetermined rolling pressure value sufficient to damage said stand and the horizontal rolls and vertical rollers.

85 A universal stand according to claim 5, wherein said mechanical nuts are screwed on to said tie-rods at a distance from the hydraulic jacks or nuts sufficient to stop said hydraulic nuts or jacks in case of a slackening of hydraulic pressure thereby avoiding damage to the stand.

9. A universal stand according to claim 3, further comprising a height spacing piece insertable between said caps and said columns for adjusting the height of said stand for accommodating use of said stand with horizontal rolls of different diameters.

10. A universal stand according to claim 3, further comprising width spacing pieces insertable between the juxtaposed half-crossbars of the stand for expanding the width thereof for accommodating use of said stand with horizontal rolls of different barrel lengths.

11. A universal stand according to claim 9, comprising width spacing pieces insertable between the juxtaposed half-crossbars of the stand for expanding the width thereof for accommodating use of said stand with horizontal rolls of different barrel lengths.

12. A universal stand according to claim 11, wherein said horizontal and vertical tie-rods are of constant length sufficient to accommodate the maximum foreseen widths and heights of the stand, and further comprising means for shortening the effective lengths of the tie-rods to accommodate reductions in the width and height of the stand from the maximum foreseen width and height without substituting tie-rods of different lengths.

13. A universal stand according to claim 12, wherein said effective length shortening means comprises height spacing pieces insertable between said caps and said vertical tie-rod tensioning means for reducing the effective length of said vertical tie-rods and between said horizontal tie-rod tensioning means and said halfcrossbars for reducing the effective length of said horizontal tie-rods.

14. A universal stand according to claim 3, wherein each vertical tie-rod comprises two identical end pieces fixed within opposed caps, and a centre piece fixed within the column therebetween, said centre piece having at each of its ends a female connecting head, and each end piece having at its interior end a male connecting head for mating with said female connecting heads of said centre piece.

1 5. An open housing two-high stand having two horizontal rolls for the rolling of shapes and convertible into an open housing universal stand comprising: horizontally separable upper, central and lower assemblies; said central assembly including four open columns, two on each side of the stand; upper and lower horizontal crosspieces disposed on each side of the stand, each upper and lower crosspiece linking the two columns on its respective side, the lower crosspiece being configured as a U lying horizontally on its side, said lower crosspiece enveloping the bases of said two columns on its respective side and extending partially along the front and back of the stand, the branches of the lower crosspieces having borings therein; eight half-crossbars, four on the front and four on the back of the stand, the half-crossbars being horizontally aligned two by two, each half-crossbar having a transverse boring therein and being linked on one of its ends with a column, the ends of the crossbars nearest the interior of the stand on either side thereof being juxtaposed with their transverse borings in alignment when the central assembly is in assembled relation, the borings of the crossbars on the lower part of the central assembly also being aligned with the borings in the lower crosspieces; a plurality of tie-rods for assembling the central assembly, a tie-rod extending through the aligned borings of each pair of juxtaposed crossbars, the. tie rods in the lower part of the central assembly also extending through the borings in the branches of the lower crosspieces; means placed on the ends of the tie-rods for tightening the central assembly; the upper and lower assemblies each comprising two caps, each cap including a strap for capping and linking the ends of two columns on one side of the stand; and means for joining said upper, central and lower assemblies and for vertically prestressing said stand.

1 6. A two-high stand according to claim 15, wherein said tightening means comprises a plurality of nuts.

1 7. A two-high stand according to claim 15, wherein said means for joining said upper, central and lower assemblies and for vertically prestressing said stand comprises: said caps and said columns having aligned vertical borings therein; a plurality of tie-rods, one extending through each group of aligned borings in said caps and columns; and means disposed on the ends of said vertical tie-rods and supported by the caps for tensioning said vertical tie-rods thereby prestressing in the vertical plane the components of the stand therebetween.

1 8. A two-high stand according to claim 1 7, further comprising means for prestressing said stand in the horizontal plane, said horizontal plane prestressing means comprising means secured to the ends of said horizontal tie-rods for tensioning said horizontal tie-rods.

19. A two-high stand according to claim 18, wherein said horizontal tie-rod tensioning means comprises a plurality of nuts one placed on each end of each tie-rod, said nut being supported by the exterior ends of the upper half-crossbars and the lateral faces of the lower crosspieces.

20. A two-high stand according to claim 18, wherein said means for tensioning said horizontal and vertical tie-rods comprises hydraulic jacks or nuts in combination with mechanical nuts, said mechanical nuts locking said hydraulic jacks or nuts after sufficient tension of the tie-rods is achieved to permit slackening of the hydraulic pressure within the hydraulic jacks or nuts after locking.

21. A two-high stand according to claim 20, further comprising: means for detecting increases in rolling pressures; means for increasing prestressing in said horizontal and vertical planes as a function of increasing rolling pressure, said means for increasing said prestressing comprising said hydraulic jacks or nuts on one side of the housing and on the top or bottom thereof.

22. A two-high stand according to claim 21, further comprising means for slackening the hydraulic pressure within the hydraulic nuts or jacks in response to a predetermined rolling pressure value sufficient to damage said stand and horizontal rolls.

23. A two-high stand according to claim 20, wherein said mechanical nuts are screwed on to said tie-rods at a distance from the hydraulic jacks or nuts sufficient to stop said hydraulic jacks or nuts in case of a slackening of hydraulic pressure thereby avoiding damage to the stand.

24. A two-high stand according to claim 18, further comprising a height spacing piece insertable between said caps and said columns for adjusting the height of said stand for accommodating use of said stand with horizontal rolls of different diameters.

25. A two-high stand according to claim 18, comprising width spacing pieces insertable between the juxtaposed half-crossbars of the stand for expanding the width thereof for accommodating use of said stand with horizontal rolls of different barrel lengths.

26. A two-high stand according to claim 24, comprising width spacing pieces insertable between the juxtaposed half-crossbars of the stand for expanding the width thereof for accommodating use of said stand with horizontal rolls of different barrel lengths.

27. A two-high stand according to claim 26, wherein said horizontal and vertical tie-rods are of constant length sufficient to accommodate the maximum foreseen widths of heights of the stand, and further comprising means for shortening the effective length of the tie-rods to accommodate reductions in the width and height of the stand from the maximum foreseen width and height without substituting tie-rods of different lengths.

28. A two-high stand according to claim 27, wherein said effective length shortening means comprises height spacing pieces insertable between said caps and said vertical tie-rod tensioning means for reducing the effective length of said vertical tie-rods, and width spacing pieces insertable between said horizontal tie-rod tensioning means and said half-crossbars or said crosspieces for reducing the effective length of said horizontal tie-rods.

29. A two-high stand according to claim 17, wherein each vertical tie-rod comprises two identical end pieces fixed within opposed caps, and a centre piece fixed within the column therebetween, said centre piece having at each of its ends a female connecting head, and each end piece having at its interior end a male connecting head for mating with said female connecting heads of said centre piece.

30, A two-high stand constructed and arranged to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.

31. A universal stand constructed and arranged to operate substantially as herein described with reference to and as illustrated in the accompanying drawings.