GB1588247A

GB1588247A - Driving apparatus for use in a strip rolling mill

Info

Publication number: GB1588247A
Application number: GB4894277A
Authority: GB
Inventors: Lothar Vogtmann; Martin Braun
Original assignee: Schloemann Siemag AG
Current assignee: SMS Siemag AG
Priority date: 1976-11-26
Filing date: 1977-11-24
Publication date: 1981-04-23
Also published as: DE2653725A1; FR2371976B3; IT1089048B; DE2653725C2; FR2371976A1

Description

(54) DRIVING APPARATUS FOR USE IN A STRIP ROLLING MILL (71) We, SCHLOEMANN-SIEMAG AKTIENGESELLSCHAFT, of Steinstrasse 13, 4000 Diisseldorf 1, Federal Republic of Germany, a joint stock company organised under the laws of the Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to driving apparatus for use in a strip rolling mill, especially a wide strip mill.

A two-roll driving apparatus is disclosed in DT-AS 24 38 759. The apparatus comprises an upper driving roll which is raisable from a lower driving roll for the free passage of the strip and which is settable against the lower driving roll for the entry of the strip into a spool for cooling. This raiseability and settability is effected by the same pneumatic or hydraulic cylinder.

Although the pneumatic or hydraulic cylinder primarily serve for the generation of the contact pressure for the upper driving roll against the lower driving roll, it is, however, also utilized for driving the upper driving roll upwards when free passage of the strip is to take place.

In that case, the pneumatic or hydraulic cylinder must be constructed to have a relatively long stroke, because raising the upper driving roll by about 500 millimetres is necessary for the free passage of the strip.

The use of a pneumatic cylinder for the generation of the contact pressure of the upper driving roll against the lower driving roll has the advantage that the upper driving roll for each pressure loading is resiliently brought into contact with the lower driving roll or the strip running through between the two driving rolls.

However, the uniform raising of the upper driving roll for the free passage of the strip with the aid of two pneumatic cylinders entails problems, because reliable synchronisation of the two pneumatic cylinders is hard to achieve and therefore canting of the upper driving roll with its supports in the stand guides is difficult to avoid.

If hydraulic cylinders are used in place of the two pneumatic cylinders, then the upper driving roll may be raised uniformly and free of canting for the free passage of the strip if the two hydraulic cylinders are synchronized. In this case, however, there is the disadvantage that resilient absorption of the roll contact force for the inlet of the strip may not be attained or only with a relatively high additional pressure, since the hydraulic fluid is practically incompressible.

According to the present invention there is provided driving apparatus for use in a strip rolling mill for feeding strip from a rolling apparatus to a coiler and comprising a stand, an upper roll rotatably mounted at each end thereof in a respective support vertically displaceable in the stand, a lower roll, hydraulically actuable piston and cylinder means to lower and raise the supports together with the upper roll to and from a rolling position, and pneumatically actuable piston and cylinder means having a shorter stroke than that of the hydraulically actuable piston and cylinder means and being so connected in series therewith as to provide means to resiliently control contact forces between the upper roll and a strip when the upper roll is in its rolling position.

Preferably the hydraulically actuable piston and cylinder means each comprise a cylinder mounted to the stand and a downwardly depending piston rod to the end of which is connected a respective pneumatically actuable piston and cylinder means.

Preferably each support comprises chock means, and the pneumatically actuable piston and cylinder means each comprise a respective downwardly depending piston rod to the end of chichis connected a respective chock means.

The hydraulically and pneumatically actuable piston and cylinder means may each be double acting.

The stand may comprise a cross-yoke to which the hydraulically actuable piston and cylinder means are mounted.

Preferably the pneumatically actuable piston and cylinder means each comprise cylinders vertically displaceable within an opening partially defined by surfaces acting as guide surfaces for the last-mentioned cylinders.

An embodiment of the present invention An embodiment of the present invention will now be more particularly described by way of example and with reference to the accompanying drawings in which: Fig. 1 shows a vertical section through a driving apparatus in which the upper roll is in a position to allow the free passage of a strip.

Fig. 2 shows the driving apparatus of Fig. 1, during the operation of running-in for thin strip, and Fig. 3 shows the driving device of Fig. 1 during the operation of running-in for thick strip.

Referring now to the drawings, a two-roll driving apparatus is shown in Figs. 1 to 3 and comprises two framelike stands, 1, of which only one is illustrated.

In the region of its lower end, each stand 1 comprises a bearing 2 for a lower driving roll 3. An upper driving roll 4 is rotatably mounted at each end thereof in a respective chock 5 which is so guided in stand windows 6 as to be vertically displaceable.

Mounted to be locally fixed on an upper cross-yoke 7 of each stand 1 is a double-acting long-stroke hydraulic piston and cylinder arrangement 8, the piston 9 of which is connected to a piston rod 10 which projects downwardly into the stand window 6 through the cross-yoke 7. A double-acting short-stroke pneumatic piston and cylinder 11, which is suspended from the piston rod 10 of the hydraulic piston and cylinder arrangement 8, is guided to be vertically displaceable in the stand window 6.

A piston 12, which is connected by way of a piston rod 13 to the chock 5 of the upper driving roll 4, is displaceable within the cylinder of the pneumatic piston and cylinder arrangement 11.

An abutment 14, which determines the lower end position of the chocks 5 and therefore of the upper driving roller 4, is provided at the lower end of the stand window 6.

In Fig. 1, the two-roll driving apparatus is illustrated in a position for free passage of the strip. In this case, the piston 9 is so acted upon by pressure means on the piston rod side that the pneumatic piston and cylinder arrangement 11 is driven up by the piston rod 10 to its upper end position. During this movement, the piston 12 is maintained at its lower end position by compressed air acting on the top of the piston 12.

In this setting of the two-roller driving apparatus, a spacing which may amount to about 500 millimetres and which thereby assures an unhindered passage of the strip to the next spool, exists between the lower driving roll 3 and the upper driving roll 4.

Fig. 2 shows the operational setting of the two-roll driving apparatus for the entry control of thick strip into the spool for coiling. In this case, the top of the piston 9 is acted upon by fluid under pressure and thereby brought to its lower end position. By way of the piston rod 10, the pneumatic piston and cylinder arrangement 11 is pushed downwards in the stand window 6. Owing to the presence of compressed air above the piston 12, the piston is also pushed downwards.

Prior to the entry of the wide strip between the two driving rolls 3 and 4, the two chocks 5 of the upper driving roll 4 have been driven against the upper side of an abutment 14, as shown in the left-hand part of Fig. 2. The periphery of the lower driving roll 3 without the pressure loading being disadvantageous.

As soon as the wide strip 16 runs in between the two driving rolls 3 and 4, the upper driving roll 4 is raised against the action of the compressed air in the cylinder of the pneumatic piston and cylinder arrangement 11, while the chocks 5 assume a spacing 17 from the abutment 14.

Since the piston 12 is loadable at its upper side by air pressure which is infinitely variable, the contact pressure of the upper driving roll 4 against the strip is infinitely variable within the desired limits. Balancing the upper driving 4 relative to the thickness of the wide strip 16 takes place automatically, because the compressed air in the pneumatic cylinder of the piston and cylinder arrangement 11 is appropriately compressible.

The operational setting of the two-roll driving apparatus for the entry of thin wide strip into the spool is shown in Fig. 3. This operational setting corresponds substantially to that shown in Fig. 2. The piston 12 is loaded at its underside by air pressure which is infinitely variable. The contact force of the upper driving roll 4 against the lower driving roll 3 or the thin wide strip 16, respectively, is infinitely variable between the force produced by weight of the complete upper driving roll 4 and no force.

Also, the upper driving roll 4 is balanced as long as the air pressure in the cylinders of the pneumatic piston and cylinder arrangement 11 does not exceed the total weight of the upper driving roll 4 with its chocks 5.

Hydraulic piston and cylinder arrangements 8 are useful practically only for raising the upper driving roller 4 for the passage of the strip. The two hydraulic cylinders of the arrangement 8 may be coupled in a simple manner through a hydraulic synchomising arrangement to avoid canting of the upper driving roll 4 by its chocks 5 in the stand windows 6.

The short-stroke pneumatic cylinder of the arrangement 11 is used for the resilient control of the roll contact force as well as for balancing the upper driving roll 4.

The operational reliability of a two-roller driving apparatus is substantially improved by separating the different functions of the pneumatic and hydraulic cylinder arrangements.

An advantage of the above described embodiment is that on raising or lowering the upper driving roll, a reliable synchronism for the two chocks is attained, and during the entry of the strip into the spool, the roll contact pressure can be absorbed with adequate resilience.

WHAT WE CLAIM IS: 1. Driving apparatus for use in a strip rolling mill for feeding strip from a rolling apparatus to a coiler and comprising a stand, an upper roll rotatably mounted at each end thereof in a respective support vertically displaceable in the stand, a lower roll, hydraulically actuable piston and cylinder means to lower and raise the supports together with the upper roll to and from a rolling position, and pneumatically actuable piston and cylinder means having a shorter stroke than that of the hydraulically actuable piston and cylinder means and being so connected in series therewith as to provide means to resiliently control contact forces between the upper roll and a strip when the upper roll is in its rolling position.

2. Apparatus as claimed in claim 1, wherein the hydraulically actuable piston and cylinder means each comprises a cylinder mounted to the stand and a downwardly depending piston rod to the end of which is connected a respective pneumatically actuable piston and cylinder means.

3. Apparatus as claimed in claim 2, wherein each support comprises chock means, and the pneumatically actuable piston and cylinder means each comprises a respective downwardly depending piston rod to the end of which is connected a respective chock means.

4. Apparatus as claimed in any one of the preceding claims, wherein the hydraulically and pneumatically actuable piston and cylinder means each are double acting.

5. Apparatus as claimed in any one of claims 2 to 4, wherein the stand comprises a cross-yoke to which the hydraulically actuable piston and cylinder means are mounted.

6. Apparatus as claimed in any one of claims 2 to 5, wherein the pneumatically actuable piston and cylinder means each comprise cylinders vertically displaceable within an opening partially defined by surfaces acting as guide surfaces for the last-mentioned cylinders.

7. Driving apparatus substantially as hereinbefore described with reference to the accompanying drawings.

8. A strip rolling mill comprising driving apparatus as claimed in any one of the preced

Claims

ing claims.