US3628366A

US3628366A - Rolling mill

Info

Publication number: US3628366A
Application number: US875703A
Authority: US
Inventors: Hermann J Leitner
Original assignee: Siemag Siegener Maschinenbau GmbH
Current assignee: Siemag Siegener Maschinenbau GmbH
Priority date: 1968-11-26
Filing date: 1969-11-12
Publication date: 1971-12-21
Anticipated expiration: 1988-12-21
Also published as: DE1810941A1; FR2024236A1; GB1270151A

Abstract

This invention relates to a rolling mill and, more particularly, to the construction of a cantilever-supported roll having means for disconnecting the roll drive in the event of an overload in the mill.

Description

United States Patent Hermann J Leitner Langenield, Germany Nov. 12, 1969 Dec. 21, 19,71 1

SIEMAG Siegener Maschlnenbau (11.111.11.1 1. llilchenbaclt-Dahlbruch, Germany Nov. 26, 19 68 Germany Inventor Appl. No. Filed 1 Patented Assignee Priority ROLLING MILL 10 Claims, 6 Drawing Figs.

u.s.c1 72/249, 72/431 1111. c1 1321b 35/14 Field oiSearch 72/237, 249, 199,431; 285/2, 3,4; 287/5201; 29/1 10, 115,121,12$;83/S43;192/150;143/32 [56] References Cited UNITED STATES PATENTS 1,183,620 5/1916 Biggert 83/543 3,491,571 1/1970 O'Brien 72/244 FORElGN PATENTS 1,224,974 6/1960 France 83/543 Primary Examiner-Charles W. Lanham Assistant Examiner-B. J. Ollila Anomey-Norman S. Blodgett ABSTRACT: This invention relates to a rolling mill and, more particularly, to the construction of a cantilever-supported roll having means for disconnecting the roll drive in the event of an overload in the mill.

PATENTEB 05021 197a 352 3 5 SHEET 1 BF 2 INVENTOR.

HERMANN J. LEITNER ATTO NEY ROLLING Mitt In the construction of rolling mills, particularly those for rolling rod which subsequently is drawn into wire, it is com mon practice to mount the rolls on shafts which extend from the housing in a cantilevered manner. Such cantilevered mounting of rolls offers anumber of advantages, including the possibility of changing rolls readily. In the construction of such cantilevered rolling'mills, it is common practice to make the rollers inthe form of rings which have the roll pass grooves formed on the outer peripheral surface. These rings are detachably mounted on the shaft and held in place by clamping them in the axial direction. Such a rolling mill design is shown in German Pat. No. 329,839; furthermore, in German Pat. Nos. 21,979 and 690,134, it has been suggested that the grooved rolls be mounted on the shaft in such a manner as to provide for changing the grooves. Along the same line, US. Pat. Nos. 1,289,602; 1,494,313 1; 1,528,392; and 2,342,159 show similar designs. French Pat. No. 1,481,623 shows the concept of an overhung grooved rolling mill used in a rod mill. German Pat. No. 490,185, as well as German Auslegeschriften No. 1,140,535 and No. 1,146,467 shows that it is old to interlock the roll and the drive shaft by means of pins.

However, all of these-prior art rolling mill rolls have the disadvantage that, when they are used in a rolling mill, it is possible to achieve safe operation in the presence of possible excess rolling forces and rolling momentum during the rolling operations only when they are connected with a rolling mill drive having a predetermined breaking point which corresponds to the maximum permissible rolling force or maximum permissible rolling momentum. Drive shafts having such a predetermined breaking point are well known, as shown in German Pat. No. 1,222,000. The main disadvantage of such a drive arrangement with a predetermined breaking point is that a relatively large mass is located between the safety elements and the roll which is acted upon during the rolling operation. The excessive force that takes part in an accident or overload has to work through this mass before it gets to the point where the safety element is operative. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.

It is, therefore, an outstanding object of the invention to provide a rolling mill having a cantilever-mounted roll, wherein means is provided between the roll and the mounting shaft for disconnecting the roll from the drive when an excessive couple is experienced by the roll.

Another object of this invention is the provision of a rolling mill having a roll which incorporates an overload device.

A further object of the present invention is the provision of an overload apparatus for use with a rolling mill in which the overload device can be changed at the same time that the roll is changed.

It is another object of the instant invention to provide an overload apparatus for use in a rolling mill, which apparatus is simple and rugged in construction, inexpensive to manufacture, and capable of a long life of useful service with a minimum of maintenance.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

SUMMARY OF THE INVENTION In general, the invention consists of a rolling mill having a housing, having a shaft mounted for rotation in the housing, and having an annular roll with a peripheral roll pass groove mounted on the shaft for rotation therewith. A locking element extends axially between the roll and the shaft, the element having a portion capable of breaking at a predetermined axial stress. An interengaging means extends between the roll and the shaft and is spaced from the locking element, which means is operative when the roll is subjected to a couple about its axis to subject the locking. element to axial stress.

BRIEF DESCRIPTION OF THE DRAWINGS I The character of the invention, however, may be best understood by reference to one of itsstructural forms, as illustrated by the accompanying drawings, in which:

FIG. 1 is a vertical sectional view of a rolling mill embodying the principles of the present invention,

FIG. 2 is a horizontal sectional view of a portion of the ap' paratus,

FIG. 3 is a vertical sectional view of a modified form of the invention,

FIG. 4 is a horizontal sectional view of the apparatus shown in FIG. 3,

FIG. 5 is a vertical sectional view of a still further modified form of the invention, and

FIG. 6 is a transverse vertical view of the apparatus shown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention consists of a rolling mill, especially a rod mill in which a driving shaft is provided with a cantileversupported grooved roll. This roll is clamped in the axial direction and is interlockedwith the drive shaft to turn with it by means of pins. A safety device is provided to ensure against excessive rolling force and excessive: rolling momentum during the rolling operation. This device acts directly on the rolling mill roll and is quite sensitive, because of the small movable mass involved. In solving this problem, the invention suggests that the axial clamping element be in the form of a bolt which has a predetermined breaking point and which is lined up with roll axis. Locking pins between the drive shaft and the roll engage surfaces which are sloped at an angle to the roll axis. Therefore, if the couple on the roll becomes too great because of an obstruction, then, in accordance with the invention, the pins between the drive :shaft and the roll act like a screw. By acting in this way, the clamping bolt is placed under stress in the direction of the roll axis. In case the couple exceeds predetermined limits (which depend on the actual material cross section present at the predetermined breaking point, on the tensile strength of the material in the anchor bolt, and on the slope of the wedge surfaces), then the predetermined breaking point is reached and the bolt breaks, thus separating the roll ring. In accordance with the invention, it is practical to make the breaking point of the anchor bolt in the same plane as the groove of the roll and in the form of a groove in the bolt. In this way, the predetermined breaking point is always in the area of the largest rolling force acting on the roll. After the anchor bolt breaks, the invention provides for each replacement in the form of a detachable pulloff Sleeve for the roll, which sleeve has a center bore for loose insertion of the anchor bolt. The shaft has a shoulder against which the head of the anchor bolt is held in the axial direction. It is possible, in accordance with the invention, to arrange several of the safety pins equally distributed around the rolls circumference. It has been found especially useful and of advantage to arrange the pins in the radial direction and resting on one side in a semicircular-shaped recess on a face of the shaft facing toward the roll. On the other side, these pins engage wedge-shaped or V-shaped grooves formed on a radial surface of the roll facing toward the face of the shaft. Other designs are possible within the framework of the invention to secure against excessive rolling force and excess rolling momentum. For instance, balls can be used in place of the pins, which balls are positioned in one side within a cup located on the face of the shaft and on the other side are positioned within a groove having a slope in the direction of the roll motion and located in a facing surface of the roll. Another design involves wedge-shaped cams formed directly on the shaft which engage corresponding wedge-shaped recesses on the facing side of the roll.

Referring first to FIG. 1, it can be seen that the rolling mill 1 is provided with a shaft 3 rotated by a drive spindle 2. A ton gue-and-groove arrangement 4 locks the spindle and shaft together. In order to secure the shaft 3 against movement in the axial direction on the spindle 2, a screw 5 is located in the shaft 3 which engages a corresponding bore 6 in the spindle 2. The shaft is supported in a plainbearing 7 in a roll housing 8 and is provided with a centering socket 9 on the front or working side of the roll housing.

The centering socket 9 on the shaft 3 has an axial hole 10 and has a supporting shoulder or counterbore 11 facing toward the spindle 2. Through the hole 10 passes an anchoring bolt 12 whose head 13 rests in the counterbore.

A ringlike roll 14 is formed with a roll pass groove 15 and has a centering flange 16 which extends into a suitable recess in the centering socket 9 of the shaft 3. The anchor bolt 12 extends in the axial direction through the roll 14 and a hole 17 formed in a clamping plate 18 which is positioned on the outwardly facing side of the roll 14. The roll is clamped by means of the clamping plate 18 and by nuts 19 on the bolt 12 which press the assemblage against the centering sleeve or shaft 3.

To lock the roll against turning on the shaft 3, carrier pins 20 are arranged in equal spacing about the roll circumference. These pins are arranged on the shaft 3 in such a way that they rest in semicylindrically shaped recesses 21 in the vicinity of the centering flange 16 of the roll, as can be clearly seen in FIG. 2. The free side of each pin 20 engages a V-shaped groove 22 on the roll, these grooves having wedge-shaped surfaces 23. The wedge-shaped surfaces 23 of the grooves 22 combine with the free part of the pin 20 and a breaking groove 24 of the bolt 12 to form safety element insuring against excessive roll forces and excessive roll momentum. In the case of an accident, the rolling momentum will exceed the permissible value and a relative turning of the roll 14 occurs relative to the shaft 3. Consequently, the wedge-shaped surfaces 23 of the grooves 22 try to climb spirally on the circumference of the pin 20. When this occurs, the roll is displaced in the axial direction and acts on the breaking groove 24 of the bolt 12. When the roll momentum exceeds the stress limit of the material cross section of the breaking groove, the bolt is overstressed and the roll separates from the shaft 3 and from the drive spindle 2. It is particularly important that the breaking groove of the bolt be positioned in line with the groove 15 of the roll, because the predetermined breaking point does not only act during the time that an excessive roll torque is arrived at, but is also effective when excessive roll forces occur and acts to separate the roll on such occasions also.

In FIGS. 3 and 4, a roll 44 is also arranged in a cantilever method in a rolling mill 31, but differs from the construction shown in FIG. 1 mainly by the use of balls 55 in place of the pins. These bails rest within corresponding cups 56 formed on a centering socket portion 39 of a shaft 33. On the front side of a centering shoulder 46 of the roll 44 are arranged grooves 57 having a slope in the direction of the motion of the roll. The rolling mill roll 44 is mounted on the shaft 33 which, in turn, is driven by a drive spindle 32 through an interconnecting means 34. A bearing 37 carries the spindle 33 in a housing 38. An anchor bolt 42 has its head 43 engaging a counterbore 41 and extends through a hole 40 in the shaft. A reduced portion or groove 54 formed on the bolt provides for breakage on occasion and nuts 49 operate with a clamping plate or sleeve 48 to hold the roll in place.

in FIGS. 5 and 6, the rolling mill 61 consists of a drive spindle 62 connected to a shaft 63 by means of a keyway 64. The shaft 63 is mounted in a bearing 67 in a rolling mill housing 68 and is provided with a centering socket 69 on which is mounted a ringlike roll 74 having a roll pass groove 75. A conical recess 76 on the roll engages a similarly shaped male cone on the shaft 63. An anchoring bolt 72 having a weakening groove 84 has its head 73 carried in a counterbore 71 in the shaft 63 and extends through a bore 70 axially of the shaft. Nuts 79 operate on the bolt 72 to hold the roll in place by cooperating with a conically shaped clamping plate 80, which engages a suitable conical recess on the outer face of the roll. The shaft 63 is provided with a finger 88 havinga sloping surface which engages a recess 89 in the roll having a similarly shaped surface 91.

Under the normal load of the rolling mill, the cam fingers 88 and the recesses 89 act together as locking means between the roll and the shaft. However, when the roll torque is increased to a point in excess of the normal load by any kind of interference or accident, a relative turning movement is created between the roll 74 and the shaft 63. Forced by this relative movement, the wedge-shaped areas 91 of the recess 89 are moved upwardly in a spiral manner along the wedge-shaped areas 90 of the cams or fingers 88. This forces the roll in the axial direction. When such action takes place in the axial direction, the groove 84 of theanchor bolt 72 is placed under stress and, if the stress is in excess of a predetermined value, the bolt will be broken. The roller 74 is then separated from the shaft 63 and, correspondingly, the rolling mill is safe against overloading. The broken anchor bolt may be readily replaced, it being only necessary to remove the shaft 63 from the end of the drive spindle 62. 7

It is obvious that minor changes may be made in the form and construction of the invention without departing from the material spirit thereoflt is not, however, desired to confine the invention to the exact form herein shown and described, but it is desired to include all such as properly come within the scope claimed.

The invention having been thus described, what is claimed as new and desired to secure by Letters Patent is:

1. A rolling mill, comprising a. a housing,

b. a shaft mounted for rotation in the housing,

c. an annular roll having an outwardly directed groove and mounted on the shaft for rotation therewith,

d. a clamping element extending axially between the roll and shaft, the element having a portion capable of breaking at a predetermined axial stress, and

e. interengaging means extending between the roll and shaft spaced from the clamping element and operative, when the roll is subjected to a force couple, to subject the locking element to axial stress.

2. A rolling mill as recited in claim 1, wherein the shaft is mounted in the housing with one end extending therefrom in cantilever fashion, wherein the roll is fastened coaxially to the said one end of the shaft by the clamping element, and wherein the clamping element is an axial bolt which has a reduced portion which will break under the said predetermined stress, the reduced portion and the roll groove lying in the same general plane perpendicular to the roll axis.

3. A rolling mill as recited in claim 2, wherein the shaft is provided with a removable clamping plate engageable with the roll to hold it in place on the shaft, wherein the plate has a central bore for receiving the bolt, and wherein the shaft has an axial bore to receive the bolt, the shaft bore having a counterbore to receive a head of the bolt and a further counterbore to receive a drive spindle.

4. A rolling mill as recited in claim 2, wherein the interengaging means consists of several cam elements associated with one of the roll and shaft and engaging a cam surface on the other of the roll and shaft, the cam element cooperating with the cam surface to produce a slight relative axial movement between the shaft and roll when the said couple is applied to the roll.

5. A rolling mill as recited in claim 4, wherein the cam element is a radially extending pin residing in a semicylindrical notch in the shaft and the cam surface is a V-shaped notch in the roll.

6. A rolling mill as recited in claim 4, wherein the cam element is a ball located in a semicylindrical notch in the shaft and the cam surface is a V-shaped notch in a roll.

7. A rolling mill as recited in claim 4, wherein the cam element is a finger extending axially of the shaft and having a surface inclined to the axis of the shaft and the cam surface is formed on a recess in the roll, which surface is inclined to the axis at the same angle as the said surface of the cam element.

8. A rolling mill as recited in claim 4, wherein the shaft is provided with a radial surface which is parallel to and spaced from a corresponding radial surface on the roll, and wherein the interengaging means extends between these two surfaces.

9. A rolling mill as recited in claim 3, wherein the roll is provided on both sides with axially extending annular flanges, wherein the shaft is provided with an annular recess to receive one of the flanges, and wherein the clamping plate is also provided with an annular recess to receive the other flange.

10. A rolling mill as recited in claim 3, wherein the roll is provided on both sides with coaxial conical recesses, wherein the shaft is provided with a male conical surface received in one of the recesses, and wherein the clamping plate is provided with a male conical surface received in the other of the said recesses.

Claims

1. A rolling mill, comprising a. a housing, b. a shaft mounted for rotation in the housing, c. an annular roll having an outwardly directed groove and mounted on the shaft for rotation therewith, d. a clamping element extending axially between the roll and shaft, the element having a portion capable of breaking at a predetermined axial stress, and e. interengaging means extending between the roll and shaft spaced from the clamping element and operative, when the roll is subjected to a force couple, to subject the locking element to axial stress.