US2034939A - Rolling mill screwdown - Google Patents

Description

March 24, 1936.- F. c. BIGGERT, JR

ROLLING MILL` SCREWDOWN Filed May 1e, 1955 Patented Mar. 24, 1936 ROLLING MILL SCREWD OWN Florence C. Biggert, Jr., Grafton, Pa., assignor to United Engineering & Foundry Company, Pittsburgh, Pa., a corporation of Pennsylvania Application May 16, 1935, Serial No. 21,830

` 14 claims.

This invention relates to rolling mills and more particularly to a screw-down type of roll-adjusting mechanism.

Rolling mill screw-downs as heretofore constructed, while capable of performing their necessary functional requirements quite satisfactorily, incorporate several disadvantages which are very undesirable. The most important of these are that such screw-downs are highly inecient and cumbersome and expensive to install and operate. This is particularly true in mills where the rolls'have to be adjusted while the material being rolled is engaged in the mill. As a rule the effective work developed from the power input to the screws in such mills runs as low as 1/, of 1 per cent. This is due to the great frictional resistance in the screw threads and in the worm gearing which is used in order to obtain the desired ratio between the speed of the driving motor and the speed of the screws.

With the foregoing in mind, it is an object of this invention to provide a screw-down which is lighter in Weight and less expensive to install, and considerably more efficient and cheaper to operate than the prior screw-downs.

A more particular object is to provide a screwdown in which a hydraulic booster is employed which is directly responsive to the screw-down proper.

These and various other objects as well as the various other novel features and advantages of the invention will be apparent when the following detailed description is read in conjunction with the accompanying drawing of which Fig. 1 is an 35 end elevation of a 4high type rolling mill embodying the invention; Fig. 2 a view similar to Fig. l showing the screw-down on an enlarged scale and the support for the booster unit in section; and Fig. 3 a sectional view taken on the 40 line III-III of Fig. 2.

Referring in detail to the embodiment of the invention illustrated in this drawing, the numeral I designates a roll housing and the numerals 2 and 3 the working and backing rolls 45 respectively of a common form of ll-high mill. The necks of these rolls are mounted in the usual fashion in a window d of the housing, the lower backing roll being disposed in a stationary lower chuck 5 and the upper in a vertically adjustable 5o upper chuck 6. For adjusting the latter a common type of adjusting screw l is employed, being threadably engaged in a threaded bore 8 extending vertically through the top of the housing. The upper end of this screw is equipped with a 55 slidably mounted worm Wheel 9 which is meshed with a worm II mounted on a shaft I2 suitably supported on the housing I and equipped with a' driving worm wheel I3. The lattenisin turn meshed with a worm I4 secured to the drive shaft I5 of a driving motor I6. 5

To increase the effectiveness of the screw-down in accordance with this invention and thereby i. the size of the screw-down equipment required, as well as its operating cost, a hydraulic' booster I'l is provided which is mounted in the housing window l at the top of the upper backing roll chuck 6. This booster as illustrated comprises a cylinder block I8 having a plurality of cylinders in its upper end which may vary in size and number, but in the present instance consists of three equal-sized cylinders I9, 2l and 22 in which there are arranged three operating plungers 23, 24 and 25, respectively. The centermost oi' these cylinders, which constitutes the master cylinder, is arranged in axial alignment with the 20 screw "Il, and its plunger 23 is adapted to be operated thereby to supply the other cylinders with operating pressure. To so function, the cylinders are all lled with an operating liquid such as oil and the lower end of the master cylinder is connected to the booster cylinders 2l and 22 by suitable ducts 2'I. The plungers 24 and 25 in the latter cylinders in order to transmit a pressure to the upper roll chuck B are disposed to engage the top of the housing window 4.

Between the lower end of the screw 1 and the top of the master plunger 23 there is provided a spacer block 28, and to permit the proper movement of the master plunger 23 which operates in the opposite direction tothe booster plungers 24 and 25, the master cylinder I9 is extended into the block I8 below the others cylinders. In addition the master plunger 23 is provided with an enlarged upper end 29 which functions as a guide and moves in an enlarged bore 3l at the upper end of the master cylinder bore I9.

Through the useV of such an arrangement, as will be' apparent, when the screw 'I is operated downwardly it causes the plunger 23 to exert a pressure on the liquid in the master cylinder I9 which is in turn communicated. to the booster cylinders 2l and 22 by way of the ducts 2l. The result of this'is that a. pressure is exerted upon the upper roll chuck 6 through the cylinder block I8 which is equal .to the force exerted on the master plunger 23 by the screw 'I plus a force exerted by the booster plungers 2li and 25 vwhich is equal to the force on the master plunger times the ratio of the cross-sectional area of the booster cylinders to the master cylinder. In the f In addition this arrangement embodies the further advantage over the old arrangements in that it distributes the force applied to the chuck 6 more uniformlyover both the top member of the housing and the chuck. As a result the beam or lever action which occurs when the pressure is all concentrated at one point is greatly reduced as is the distortion produced thereby which in the prior constructions requires additional material to counteract it. s

While, as previously stated, the number of the cylinders in the booster may be varied as well as their diameters, it will be appreciated that the stroke of the screw and the multiplication of pressure in the booster vwill vary with the ratios of the cross-sectional area of the booster cylinders to the master cylinder and that the length of the housing Window will be determined by the required movement of the screw. It is for this reason and to balance the construction that three equal-sized cylinders are recommended. It will also be obvious that the booster cylinders may be formed in the upper roll chuck itself.

According to the provisions .of the patent statutes, I have explained the principle and mode of operation of my invention and have illustrated and described what I now consider to represent its best embodiment. However, I desire to have it understood that, withinthe scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

l. In a rolling mill, a power-driven screw for adjusting the mill rolls, and a hydraulic booster for assisting said screw in applying a pressure to vthe rolls.

2. In a rolling mill, a power-driven screw for adjusting the mill rolls, and a hydraulic booster operated by said screw for increasing the pressure applied to the rolls.

3. In a rolling mill, a roll housing, an upper 'roll-necksupporting chuck mounted in a window in said housing, a hydraulic booster in the top of said Window, a master plunger mounted in a master cylinder in said booster, a plunger mounted in a booster cylinder also located in said booster to engage the topof said window, a power-operated screw located in the top of said housing and disposedv to operate said master plunger, an operating uid in said cylinders, and means connecting said cylinders together.

4.,In a rolling mill, a roll housing, an upper roll-neck supporting chuck mounted for vertical adjustment in a window in said housing, a cylinder block mounted in said window above said block, a power-driven screw mounted in the top of said housing for adjusting said chuck, a master cylinder located in said block below said screw, a master plunger mounted in said master cylinder for operation by said screw, a booster cylinder mounted in said block, a booster plunger mounted with one end in said booster cylinder and the other engaging the top of said window, a

"chuck, a cylinder block mounted on top of said supply of uid in said cylinders, and means connecting said cylinders together.

5. In a rolling mill, a roll housing, an upper roll neck supporting chuck mounted in va window in said housing, a power-driven screw mounted in 6 the top of said housing for adjusting said chuck, a cylinder block mounted on top of said chuck, a master cylinder in said block,a master plunger provided in said cylinder and arranged to be operated by said screw, a plurality of booster cylinders in said block communicating with said master cylinder, booster plungers arranged in said booster cylinders with their outer ends engaging the top of said window, and a supply of iluid in said cylinders.

6. In a rolling mill, a roll housing, a roll neck supporting chuck mounted for vertical adjustment in a window in said housing, a power-driven screw mounted in said housing for adjusting said 20 chuck, a master cylinder in the top of said block, a pair of booster cylinders at opposite sides of said master cylinder,x a master plunger disposed in said master cylinder for operation' by said screw, a pair of booster plungers mounted in said booster cylinder and disposed to engage the top of said Window, a supply of liquid in said cylinders, and means connecting said cylinders together.

7. A screw-down according to claim 5 in which the master and booster cylinders are of equal diameter.

8. In a rolling mill, a roll housing, a roll neck supporting chuck mounted in a window in said housing, a power-driven screw for adjusting said chuck mounted in the end of said housing, a cylinder block mounted on top of said chuck in said window, a booster cylinder in the top of said block, a booster plunger mounted in said cylinder with its upper end engaging the end of said window, a master cylinder located in said block with its closed end projecting thereinto beyond the endy of said booster cylinder, a master plunger provided with an enlarged outer end mounted in said master cylinder with its enlarged outer end engaged in an enlargement of said cylinder and disposed for operation by said screw, a supply of liquid in said cylinders, and means connecting their closed ends together.

9. In a rolling mill, a roll adjusting screw, a roll-neck supporting chuck, and a hydraulic booster system disposed for operation between said screw and chuck. 4

10. In a rolling mill, a roll housing, a roll-adjusting screw mounted in said housing, arollneck supporting chuck mounted in a window in said housing, and a hydraulic booster system operative between said screw and chuck.

11. In a rolling mill, a roll adjusting screw, a roll-neck supporting chuck, and a hydraulic booster disposed for operation -by the thrust of said Ascrew and effective for increasing the pressure exerted by the screw on the chuck.

12. In a rolling-mill, a rollhcusing,a rollneck supporting chuck mounted in a window in said housing, a hydraulicy booster in said window, a master plunger mounted in a master cylinder in said booster, a plunger mounted in a. booster cylinder also located in said booster to engage an end of said window, a power-operated 70 'screw located in said housing yand disposed `to supporting chuck mounted in a window in said housing, a power-driven screw mounted in said housing for adjusting said chuck, a master plunghousing, a pressure block disposed between said chuck and the adjacent end of the window in said housing, a power-driven roll-adjusting screw disposed in said housing ,opposite the center of said pressure block, a master cylinder in said pressure block opposite said screw, a master plunger disposed in said master cylinder for operation by said screw, a pair of auxilary cylinders disposed at opposite sides of said master cylinder and communicating therewith, and a pair of auxiliary plungrs disposed to t in said auxiliary cylinders and engage the adjacent end of the housing window.,

FLORENCE C. BIGGERT, Je.

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