US2865575A

US2865575A - Strip coiling mandrel

Info

Publication number: US2865575A
Application number: US558574A
Authority: US
Inventors: Alfred H Werner
Original assignee: United States Steel Corp
Current assignee: United States Steel Corp
Priority date: 1956-01-11
Filing date: 1956-01-11
Publication date: 1958-12-23
Anticipated expiration: 1975-12-23

Description

Dec. 23, 1958 A. H. WERNER 2,865,575

STRIP COILING MANDREL Filed Jan. 11, 1956 16/5 4171 K/QJTKQ 0,94 70 57/64 fv/c/r/yars //v VEMTOl-P. ALFRED H. WERNER,

his Alforney.

United States Patent G r:

STRIP COILIN G MA'NDREL Alfred H. Werner, Youngstown, Ohio, assignor to United States Steel Corporatioma corporation of New Jersey Application January 11, 1956, Serial No. 558,574

3 Claims. (Cl. 2427842) This invention relates to an improved mandrel of the type used in combination with retractable wrapper rolls for coiling metal strip.

An object of the invention is to provide an improved mandrel which prevents the leading edge of a strip from damaging either the inner convolutions of a coil formed on the mandrel, the mandrel itself, or the wrapper rolls.

A further object is to provide an improved mandrel whose circumference carries means for automatically depressing the leading edge of a strip sufliciently that it leaves no ridge which might damage any of the foregoing parts.

A further object is to provide an improved mandrel which eliminates the need for tight engagement between the wrapper rolls and strip for starting a coil and consequently eliminates any pounding action on the strip as the wrapper rolls make contact.

A further object is to provide a mandrel suitable for coiling hot strip of heavier gauges than is possible with conventional mandrels.

A more specific object is to provide a mandrel whose circumference is formed as a series of alternating smooth ribs and grooves of a minimum height or depth equal to the strip thickness, one of said grooves automatically receiving the leading edge of the strip and depressing it sufiiciently that it leaves no ridge capable of causing damage.

In accomplishing these and other objects of the invention, I have provided improved details of structure, a preferred form of which is shown in the accompanying drawing, in which:

Figure l is a schematic elevational view of a typical mill in which my improved mandrel can be incorporated;

Figure 2 is a vertical cross-sectional view of my improved mandrel; and

Figure 3 is a side elevational view of my mandrel.

Figure 1 shows schematically a portion of a typical hot strip rolling mill which includes a plurality of finishing stands 10, a set of pinch rolls 12, a mandrel 13, and retractable wrapper rolls 14 surrounding said mandrel. Strip S travels through the finishing stands and pinch rolls and is coiled on the mandrel. Co-nventionally the wrapper rolls hold the strip on the mandrel to start the coil and thereafter guide the strip, retracting as the coil builds up. This type of mechanism, apart from my mandrel, is conventional and hence is not shown in detail. For a more detailed disclosure of wrapper rolls and their operation, reference can be made to Iverson et a1. Patent No. 1,935,092 dated November 14, 1933, or Washam Patent No. 2,325,559, dated July 27, 1943, although it is apparent my invention is not limited to the specific mechanisms shown in these patents.

As shown in Figure 2, my improved mandrel comprises a cylindrical body 15 and a plurality of spaced ribs 16 fixed to the circumference of said body. The body is shown as formed of a plurality of expandable segments, although my invention is applicable as well to solid cylindrical mandrel bodies. The ribs 16 are pui- 2,865,575 Patented Dec. 23,4958

formly spaced around the circumference leaving depressions 17 therebetween and each rib extends the full length of the mandrel body parallel to the axis of rotation thereof. The minimum height of each rib at least equals the thickness of the strip S. Preferably the ribs have a substantially airfoil shape in cross section to provide a smooth surface throughout, although other cross-sectional shapes are operable. If the ribs are of rectangular cross section, for example, in service they wear to a cross section similar to that shown. It is also apparent that an equivalent structure could be produced by machining the depressions 17 into the mandrel surface. Nevertheless, I prefer to fix the ribs to the body in order that they may be removed and replaced when Worn.

In operation, as a coil is started, the conventional practice is followed of driving the mandrel 13 slightly faster than the strip speed to develop tension in the coil. However, frictional forces between the strip and my improved mandrel are sufficient to hold the strip on the mandrel to start the coil, and it is not necessary to use the Wrapper rolls for this purpose. In fact these rolls can be replaced with smooth faced guide plates. When the strip S first contacts the mandrel, the leading edge automatically enters one of the depressions 17. If the edge happens initially to overlie a rib 16, the greater speed of the mandrel produces enough slippage that the edge enters the next depression rather than remaining on top of the rib. Consequently there is no ridge at the line where the leading edge lies on the mandrel, and the first convolution of the coil overlies a smoothly curved surface at this line. There is no tendency for the leading edge to score or otherwise damage the inner convolutions of the coil. Likewise the force of the wrapper rolls 14 against the mandrel does not tend to damage either the mandrel surface or the rolls themselves.

The thicker the strip, the more significant these ad vantages become. In fact I have successfully coiled hot strip of gauges too thick to coil on a conventional mandrel. Such mandrel is water-cooled, and the heat of the hot strip immediately converts the water to steam, which acts as a lubricant. My depressions l7 allow the steam to escape and thus avoid its lubricating eifect which heretofore has limited the gauge of strip that could be coiled.

While I have shown and described only a single embodiment of my invention, it is apparent that modifications may arise. Therefore, -I do not wish to be limited to the disclosure set forth but only by the scope of the appended claims.

I claim:

1. The combination with strip guiding means, of a coiling mandrel for the strip comprising a rotatable cylindrical body having a substantially continuous outer circumferential face, and a plurality of fixed ribs spaced around said circumferential face leaving a series of depressions therebetween for frictionally holding strip on said body, each of said ribs extending the length of said body parallel to the axis of rotation thereof and being of a minimum height at least equal to the strip thickness enabling the leading end of the strip to remain substantially unbent and to bear against said circumferential face within any one of said depressions, said guiding means at least partially surrounding said body.

2. The combination with a set of pinch rolls adapted to propel strip and a strip guiding means on the exit side of said pinch rolls of a coiling mandrel for the strip comprising a rotatable cylindrical body having asubstantially continuous outer circumferential face, a plurality of fixed ribs spaced around said circumferential face leaving a series of depressions therebetween for frictionally holding strip on said body, each of said ribs rotation thereof and being of a minimum height at least equal to the strip thickness enabling the leading end of the strip to remain substantially unbent and to bear against said circumferential face within any one of said depressions, and means for driving said body faster than the speed at which said pinch rolls propel the strip, said guiding means at least partially surrounding said body.

3. The combination with a set of pinch rolls adapted to propel strip and a set of retractable wrapper rolls on the exit side of said pinch rolls for guiding the strip, of a coiling mandrel for the strip comprising a rotatable cylindrical body at least partially surrounded by said wrapper rolls, said body having a substantially continuous outer circumferential face, a plurality of ribs removably fixed to said body and spaced around said circumferential face leaving a series of depressions therebetween for frictionally holding strip on said body, each of said ribs extending the length of said body parallel to the axis of rotation thereof and being of a minimum height at least equal to the strip thickness enabling the leading end of the strip to remain substantially unbent and to bear against said circumferential face within any one of said depressions, and means for driving said body faster than the speed at which said pinch rolls propel the strip and enabling slippage between the leading end of the strip and said body to position the leading end within a depression and thereafter tensioning the strip.

References Cited in the file of this patent UNITED STATES PATENTS 1,492,954 Biggert May 6, 1924 1,952,181 Newill Mar. 27, 1934 2,116,121 Montgomery May 3, 1938 2,733,023 Lewis et al. Jan. 31, 1956