US2959992A

US2959992A - Master control device for rolling mills and the like

Info

Publication number: US2959992A
Application number: US613787A
Authority: US
Inventors: Clarence R Mitchell
Original assignee: Granite City Steel Co
Current assignee: Granite City Steel Co
Priority date: 1956-10-03
Filing date: 1956-10-03
Publication date: 1960-11-15
Anticipated expiration: 1977-11-15

Description

Nov. 15, 1960 c. R. MITCHELL MASTER CONTROL DEVICE FOR ROLLING MILLS AND THE LIKE e 3 m \N 5 Nu a NW m s W 2 N \N \N \N U M Filed Oct. 3, 1956 Avrewrnet (Uravmfflrma;

2 Sheets-Sheet 2 C. R. MITCHELL Nov. 15, 1960 MASTER CONTROL DEVICE FOR ROLLING MILLS AND THE LIKE Filed Oct. 3, 1956 Unite MASTER CGNTRUL DEVICE FOR ROLLING mLS AND THE LIKE Filed Oct. 3, 1956, Ser. No. 613,787

1 Claim. (Cl. 8056) This invention relates generally to control devices and more particularly to master control devices employed for adjusting rolling mill equipment and the like and enables an operator selectively to individually or simultaneously adjust the positions of the mill rolls at a plurality of mill stands.

In the rolling mill art, it is well known to employ screw down motors at the various rolling stands to adjust the spacing between the respective work rolls and thereby to adjust the thickness of the material being rolled. However, it has not been proposed heretofore to provide a single master control device, conveniently situated, and simple to operate for controlling the screw down motors at a plurality of stands simultaneously and yet which permits the stands to be separately adjusted when necessary.

It is therefore an object of this invention to provide an inexpensive yet versatile master control device, conveniently situated, for simultaneously adjusting a plurality of rolling stands in a rolling mill.

Another object of the present invention is to provide a master control device which simultaneously adjusts the work roll spacing at a plurality of rolling mill stands while maintaining the load distribution between stands.

Another object is to provide a master control device which is adaptable for use with other known control devices such as individual mill stand control devices and which makes the operation of the known devices more versatile.

Another object of the present invention is to provide a control device for rolling mills and the like which speeds up the adjustment procedure, reduces waste, and cuts down on the number of operators.

Yet another object of the invention is to provide a control device for adjusting a plurality of mill stands in a rolling mill which reduces time normally lost changing the rolling operation.

Briefly, the present master control device is adapted to be employed with rolling mills having a plurality of stands each of which is provided with work rolls for reducing the thickness of sheet material and each of which is provided with screw-down means for adjusting the positions of the work rolls and comprises means connected to the screw-down adjusting means at a plurality of rolling mill stands for simultaneous adjustment thereof and means for locking out the individual stand adjusting means during said simultaneous adjustment.

Other objects and advantages of the present invention will become apparent after considering the following detailed description in conjunction with the accompanying drawings.

In the drawings:

Fig. l is a side elevational view, partly cut away, of a plurality of spaced mill roll stands in a rolling mill,

Fig. 2 is a top plan view of the mill roll stands shown in Fig. 1,

Fig. 3 is a schematic wiring diagram showing illusice tratively one form of controls for the rolling mill stands shown in Figs. 1 and 2, and

Fig. 4 is a schematic wiring diagram showing the master control portion of the controls for the rolling mill.

Rolling mills that produce sheet material from bulkier forms, such as mills for rolling steel ingots into sheet steel, are in common use in many phases of industry. Certain of these, because of the nature of the material being rolled, provide a plurality of rolling standsor stations, each performing part of the overall reduction in thickness. In such milling operations it is desirable, if not essential, to distribute the work load betweenthe various stands so that no single stand exceeds its working capacity and wears out prematurely. Furthermore, it is desirable to be able to adjust all of the stands simultaneously, or individually, if necessary, to quickly correct errors in the thickness of the finished material. Naturally, the production of oif-gauge material results in waste, inefficiency and lost time, all of which are reduced by the present device. Still further, it is desirable to be able to make these corrective adjustments while maintaining a suitable distribution of work load between the stands. The drawings show a master control device, referred to by number 10 (Fig. 4), which is constructed according to the teachings of the present invention. The device 10 may be installed as original equipment in a rolling mill or as an improvement on an established mill. In either case, the principles of operation and the advantages thereof are substantially the same; namely, quicker more versatile adjustment of the rolling stands, maintenance of load distribution between stands, less waste due to oil-gauge material, and efiicient operation with fewer operators.

Fig. lshows a plurality of spaced mill roll stands 12 in a sheet rolling mill such as for steel sheet W. Each mill stand 12 includes an upper work roll 14, a lower work roll 16, an upper adjustable back-up roll 18 and a lower stationary back-up roll 20. The work rolls 14 and 16 are driven and frictionally engage and drive the back-up

rolls

18 and 20 respectively, and the stands 12 are adjusted by varying the spacing between the

work rolls

14 and 16. Front and rear screw-down

motors

22 and 24 respectively, are provided on each of the stands 12 (Fig. 2). The operation of the screw-down

motors

22 and 24 changes the work roll spacing and is under the control of switches and relays which will be described hereinafter.

The screw-down

motors

22 and 24 have shafts 26 and 28 respectively, which drive worm gears 30 and 31 operatively connected thereto. The worm gears 30 and 31 are meshed with gears 32 and 33 respectively and move front and rear vertical screw-down

members

34 and 36 that operate to adjust the positions of front and rear end bearing members. One bearing member 38 is seen in Fig. l and the others are similar and have not been shown. Shaft 42 in each stand carries the upper back-up roll 18, and by adjusting the vertical position of the shaft 42 and the associated roll 18, the spacing between work rolls 14- and 16 is adjusted. The present device could also be employed with various other stand constructions. For example, the back-up

rolls

18 and 20 could be eliminated and the work rolls 14 and 16 adjusted directly, or the

lower rolls

16 and 20 could be adjusted instead of the

upper rolls

14 and 18. In the embodiment shown for illustrative purposes, the Work rolls 14 are biased upwardly against the rolls 18 in a manner well known in the rolling mill art so that the material being rolled does not have to support the work rolls 14 and the back-up rolls 18 and so that the spacing between

work rolls

14 and 16 is maintained.

By equipping rolling mills with the present device, complete flexibility of stand adjustment is obtained. For

taneously to change the work roll spacing, they can be adjusted separately (called jogging) to provide equal or unequal longitudinal spacing between the work rolls, they canbe adjusted in opposite directions simultaneously when the error in longitudinal roll spacing is great, and they can be moved at high speed or at low speed as the situation requires.

, The above adjustments as applied to an individual stand have been known in the milling art heretofore. However, where a plurality of stands 12 are employed for a single rolling operation, the limited individual stand controls make it necessary to have an operator positioned at each stand 12 or else to move several operators from stand to, stand to make adjustments. The disadvantages of such operation are obvious; it means that for each adjustment the distribution of work between the stands is altered, it means valuable time is wasted making adjustments, it means off-gauge material is rolled while adjustments are being made, it means constantly rechecking'the thickness of the finished material, and it means a large number of operators are required to make adjustments.

To overcome these disadvantages, the present device, which is embodied in a master control switch 46 and related electric circuits, is incorporated into a mill control system.

The master control switch 46 is provided with five operating positions (Figs. 3 and 4). In the central or de-energized position 48, the switch 46 is inoperative and each of the mill stands 12 can be adjusted (or jogged) individually as described above. In the other four

positions

50, 52, 54 and 56, the individual controls for the stands 12 are locked out and rendered ir1- operative, and the master control switch 46 has complete control over the adjustment of the stands 12. Furthermore, in the

positions

50, 52, 54 and 56 the adjustment of all the aifected stands is simultaneous and is in the same direction.

In

positions

50 and 54, which are the control points for adjusting all mills upwardly, the master switch 46 operates to move all of the screw-down

members

34 and 36 upwardly in a direction to increase the spacing between

work rolls

14 and 16. In positions 52 and 56, the mills are downwardly adjustable. Positions 54 and 56, are employed with the

positions

50 and 52 respectively, to increase the speed of adjustment by operating the screw-down

motors

22 and 24 at higher speed. Conventional motor control circuits are employed for this purpose, and indicated at 47 (Fig. 3).

The switch 46 is located near the final stand 12. This permits an operator positioned there to observe the thickness (on any suitable gauge) of the finished material coming out of the final mill roll stand 12 and to make necessary corrective adjustments. Whenever an error in thickness is detected by the operator, he can make the necessary correction by operating the master switch 46 without changing his position and without changing the relative work loads of the stands 12. Furthermore, should an individual stand need jogging or individual adjustment, this can be accomplished (while the mill is operating) with the master switch 46 in the de-energized position 48.

Schematic wiring diagrams, including the circuit elements employed with the switch 46, are shown in Figs. 3 and 4. The circuit diagrams have been greatly simplified to make them easier to understand.

Fig. 4 illustrates diagrammatically the electrical components associated most directly with the switch 46. Also diagrammatically shown are the five operating positions (48, 50, 52, 54 and 56) of the switch 46. When the switch 4 6 is in the inoperative or neutral position 48 (which is the locked out position), relay 60 is energized. The relay 60 when energized causes transfer contact points 62 (Fig. 3) to establish circuits that enable the various stands 12 to be separately controlled for jogging and the like. The contacts 62 are shown in Fig. 3 ganged together so that they all engage their associated left-hand contact terminals 64:: and 64b in the de-energized position of relay 6%. When the relay 6% is energized (as it is in position 48 of the switch 46), the transfer contacts 62 engages stationary terminals 66a and 6612 instead and the individual stand controls are then operative. When relay 6i) is de-energized, spring 68 (Fig. 3) causes the contacts 62 to move to their left positions. In Fig. 3, the transfer contacts 62 are shown for the sake of clarity at an intermediate position midway between stationary contacts 64 (a and b) and stationary contacts 66 (a and b).

In the locked out position (with relay 6% energized and the contacts 62 in their rightward positions), circuits are available from every screwdown motor to the individual stand up and down switches 76, 72, and 74. The push button switches 76' (which are connected to a source of energy indicated by the symbols 8+) when operated move the single associated screw-down motors up. Similarly, switches 72 are operated to individually move the associated screw-down

motors

22 or 24 down. Switch '74 at each station 12 is provided with a transfer contact 76 and two cooperating normally

open contacts

78 and 80. The contact 78 is connected to both of the up switches at the associated stand 12- and to the up terminals on the associated front and rear screw-down

motors

22 and 2 4. The contact 36 is similarly connected to both of the down switches '72 and to the down terminals on the associated front and rear screw-down

motors

22 and 24. When the transfer terminal 76 at a stand is moved into engagement with the terminal 78 (and switch 46 is in position 48), both the front and rear screw-down

motors

22 and 24 at the associated stand 12 move up wardly together, and when the transfer terminal 76 is moved downwardly into engagement with the contact 80, the associated front and rear screw-down

motors

22 and 24 move downwardly together.

The individual stand controls (under control of switches 76, '72, and 74) are dependent upon the lock out relay 60 being energized. This in turn depends upon the master control switch 46 being in the central position 48. If the master switch 46 (Fig. 3) is moved into any other position, the relay 6% becomes de-energized and all of the transfer contacts 62 move to the left into engagement with the contacts 64a and 64b.

In positions 59 and 54 of the switch 46, a circuit is available from 13+ through the switch operating arm 82 (which is a conductor) to the contact at positions 51 and 54, and from there upwardly on line 81 to all of the terminals 64:: corresponding to the up connections on the screw-down

motors

22 and 24.

if the switch 46 is moved to either of the right positions 52 and 516, the relay (ii) is again de-energized and a circuit is available from positions 52 and 56 on line 83 to all the down terminals 64b. Therefore, in

positions

50 and 54 all of the screw-down

motors

22 and 24 are simultaneously energized to increase the spacing between the work rolls 1d and 16, and in positions 52 and 56 all of the screw-down motors 22 and 24- are simultaneously energized to decrease the spacing between the work rolls.

When the switch 46 is moved into positions 54 and 56, an additional terminal is contacted by the switch operating arm 82 which energizes additional circuitry to means 4 for increasing the speed of the screw-down

motors

22 and 24. Therefore, in positions 54 and 56, circuits are available to energize all of the screw-down

motors

22 and 24 at high speed in their respective directions. The increased speed at which the screw-down motors operate when the master switch 46 is in positions 54, and 56, speeds up the adjusting procedure and is particularly handy when changing over from one rolling operation to another.

In Fig. 4-, the five positions of the switch 46 are shown diagrammatically to further illustrate the operation. In

the various positions of the switch (48, 5%, 52, 54 and 56) the switch 46 energizes a different control relay. In position 48, as described above, the relay 60 is energized, in position 50, relay 84 (the all-mills-up relay) is energized, in position 52, the relay 86 (the all-mills-down relay) is energized, and in positions 54 and 56, relay 88 (the all-mills-high speed relay) is energized. Relay 90 is also connected across the lines to the switch 46. The relay 90 has normally open contacts connected in series with

relays

84, 86 and 88 for voltage protection thereof.

It is now apparent that a control device has been provided for rolling mills that employ a plurality of reducing stands that simultaneously adjusts a plurality of the stands. Furthermore, a master control device has been provided which enables the stands to be individually adjusted to compensate for wear and/or unequal distribution of load.

Thus, it is apparent that there has been provided a novel master control device for rolling mills that fulfills all of the objects and advantages sought therefor. It is to be understood that the foregoing description and accompanying drawings have been presented only by way of illustration and example and that changes and alterations in the present disclosure which will be apparent to those skilled in the art are contemplated as being Within the scope of this invention which is limited only by the claim which follows.

What I claim is:

Means for controlling the thickness of sheet material being reduced by a rolling mill operation comprising a rolling mill having a plurality of spaced unidirectional roll stands, each of said stands having spaced upper and lower work rolls and means thereat for changing the position of one of said work rolls relative to the other work roll to adjust the spacing therebetween, said last named means including for each of said stands separate motor means operatively connected to each end of said one work roll, and control means including electric circuit means, switch means, and speed and direction control means connected to each of said separate motor means, said switch means being selectively movable to a plurality of difierent operating positions to individually or simultaneously energize the motor means at the associated stand in 'a desired direct-ion and at a desired speed to elfect adjustment of the spacing of the Work rolls thereat, said motor means being capable of being energized during a material reducing operation; and master control means operatively connected to the motor means and the individual stand control means at a plurality of said stands and including multi-position master switch means, electric circuit means and motor speed and direction control means, said master switch means being movable to a plurality of different operating positions to efiect simultaneous energization in a selected direction and at selected speed of the motor means at said plurality of stands, said master control means being effective during material reducing operations and including means for disabling the control means at the individual stands during operation thereof.

References Cited in the file of this patent UNITED STATES PATENTS 1,466,642 Crook Aug. 28, 1923 1,764,312 Ienks June 17, 1930 2,017,040 Dahl Oct. 15, 1935 2,106,965 Wright Feb. 1, 1938 2,124,518 Marquart July 19, 1938 2,564,284 Schurr Aug. 14, 1951 2,708,254 Macaulay et al. May 10, 1955