US3150419A

US3150419A - Magnetically weighted pressure rolls

Info

Publication number: US3150419A
Application number: US226936A
Authority: US
Inventors: Christoph W Aurich
Original assignee: Maremont Corp
Current assignee: Maremont Corp
Priority date: 1962-09-28
Filing date: 1962-09-28
Publication date: 1964-09-29
Anticipated expiration: 1981-09-29
Also published as: ES292030A1; DE1169814B; CH426571A

Description

SePf- 29, 1964 c. w. AURICH 3,150,419

MAGNETICALLY WEIGHTED PRESSURE ROLLS Filed Sept. 28, 1962 20c FIGZ United States Patent O Fce 3,156,419 MAGNETICALLY WEIGHTED PRESSURE ROLLS Christoph W. Aurich, Clemson, S.C., assigner, by mesne assignments, to Maremont Corporation, Chicago, Ill., a corporation of' Iliinois Filed Sept. 28, 1962, Ser. No. 226,936 10 Claims. (Cl. 19-272) This invention relates to rolls used in applying pressure to material moving thereagainst, such as drafting rolls, calendering rolls and the like. More particularly the invention relates to constructions and means of a magnetic nature for weighting such rolls in order to apply pressure to material passing between a pai-r of rolls.

The invention is useful in drawing mechanisms of the type used in tex-tile machines such as spinning, roving, drawing frames, comber draw boxes and the like, where pressure is applied to fibrous material passing between pairs of rolls. The invention also may be applied in analogous paper making or processing machines where pressure is applied by rolls to sheets or webs of stock passing between the rolls, such as couch rolls, press rolls, calenders and the like.

In each of these mechanisms one or both of a pair of cooperating rolls is rotatably driven to carry material between the rolls, and pressure is applied between the rolls sufiicient to cause the necessary drafting, calendering or other pressure treatment of the material for which the mechanism is designed. Although weights, springs, levers and hydraulic or pneumatic pressure systems often are used to weight the upper roll or lift the lower roll in a pair in order to apply the desired pressure between the rolls, the present invention does not relate to such weighting arrangements with their attendant difficulties and problems but relates to improvements in the magnetic weighting of rolls. In magnetic weighting, one or both rolls of as many pairs as may be desired consists of or includes a magnet, the rolls being so associated that the magnetic force pulling them together applies sufficient pressure between them. No weights, springs, levers or like mechanisms for weighting `the rolls are therefore required.

In prior magnetic pressure rolls the internal magnets, having low structural strength themselves, are contained within and supported by outer cylinders of heavy brass, bronze, aluminum or other metals of non-magnetic or diamagnetic character. Non-magnetic materials are used in order to provide necessary reluctance and prevent flux loss by leakage between pole pieces at the ends of the magnets. Unfortunately, brass and such economically acceptable diamagnetic materials are not noted for struc- Itural strength, and the sizes of prior magnetic rolls using such materials are therefore limited. The thickness or cross-section of a brass or other non-magnetic shell, necessary to provide mechanical strength and support, often reduces the magnetic weighting effect which otherwise might be obtained because a thicker shell reduces the diametrical space available for magnet accommodation for any given outside diameter of roll. On such rolls also, the shells, the magnets and the pole pieces must be provided with structures holding the parts together, on or by which the gudgeons or journals for rotatably supporting the rolls can be dependably secured, and sometimes resilient cots or coverings must be mounted on such rolls.

One object of the present invention is to provide magnetic rolls for the purposes described which are simple in construction, easy to manufacture, compact, solid, and which may be made in smaller diameters, of greater length and of lighter weight than magnetically weighted rolls previously available. Another object is to provide such rolls in which, by magnetic forces, higher pressures and 3 l 5 ,4 l 9 Patented Sept. 29, l 964 larger spacings between rolls may be obtained for the treatment of heavier slivers or webs of material than heretofore. A further object is to provide improved srtuctures in such rolls for securing supporting journals thereto and for mounting cots thereon.

The principal objects of the invention are met generally by eliminating the usual non-magnetic or diamagnetic tubes or sleeves surrounding the magnets and pole pieces in the rolls, and providing a strong, thin-walled tube, sleeve or cylindrical shell of steel or similar magnetic, i.e. ferrous, magnetizable, material. Although the use of a sleeve of such magnetic material would seem unduly to reduce the reluctance of the magnetic circuit, adding undesirable leakage, it has been found that by using a highly permeable material and by keeping the shell wali as thin (small in cross-section) as practically possible, by magnetically saturating the sleeve, considerable reluctance is provided, minimizing the leakage flux or flux loss. Good results are obtained using dimensions and proportions acceptable in equipment of the type here involved with the shell cross-sectional area reduced to a minimum compatible with required mechanical strength characteristics. Simplified construction of the roll is possible, as hereafter described, by virtue of the character of the shell material.

Other objects, advantages and further details of that which is believed to be novel and included in this invention will be clear from the following description and claims, taken with the accompanying drawings in which are illustrated examples of pressure rolls embodying the present invention and incorporating magnets enclosed within strong but thin walled shells of magnetic material such as steel.

In the drawings:

FIG. 1 is a front elevational view of a set of drawing rolls embodying one form of this invention;

FIG. 2 is a vertical sectional view of a set of drawing rolls according to another form of this invention;

FIG. 3 is a front elevational view, partly in section, of a set of calendering rolls embodying the invention;

FIG. 4 is an enlarged vertical sectional view through the end of one of the top rolls in the form of FIG. l;

FIG. 5 is a similar enlarged sectional View of the end ofthe top roll in the form of FIG. 2, and

FIG. 6 is a corresponding enlarged sectional view through the end of Ithe bottom roll in the form of FIG. 2.

In the various figures of the drawings the same basic elements in the different forms of the invention are given the same numbers throughout, with the addition of differentiating letters to identify Variations in form of these elements.

Drafting mechanisms of the type shown in FIG. 1 include a series of top rolls 10, shown in detail in FIG. 4, and a single bottom roll or shaft 12 suitably rotated by a drive (not shown) in a manner well known. Protuberant annular bosses of resilient material, 14, also sometimes called cots or covers, are provided on the top rolls and receive power from the rotating bottom rolls by contact with areas of fine fluting or ribs 16 on the bottom roll. The cooperating cots and fluted sections produce a continuously uniform bite or nip and conform to the sllape of a sliver or other fibrous material fed between t ern.

The upper rolls in this form are provided with gudgeons 20 at their ends journaled in slots in cap bars 22 as is usual in this type of drafting mechanism. The driven lower roll or shaft is suitably supported and journaled as in a roll stand at 18.

In order properly to weight the rolls and apply the desired pressure between the resilient bosses and cooperating tinted sections, each of the top rolls in the form of FIGS..

l and 4 is provided with and consists principally of a permanent magnet 2S of cylindrical form, which, according to this invention, is closely surrounded by a, uniformly thin shell 30 of steel or similar structurally strong metal capable of being magnetized. At each end of the magnet, held tightly thereagainst, a pole piece is provided which preferably is secured directly to or fabricated integrally with one of the gudgeons Ztl. The pole pieces, preferably of soft steel, are pressed and secured tightly within the ends of the cylindrical shell and against the magnet ends by spinning over or rolling the edges of the shell, by welding, or in some other suitable` fashion as at 34. Immediately outside of the pole Pieces, on either end gudgeon of each top roll of this form, the cots 1li above mentioned are secured as by slipped over the gudgeons and cemented or otherwise lirmly secured to rotate simultaneously with the rest of the top roll.

The bottom roll or shaft 12 in this form may be made entirely of magnetic steel so that the magnetic iiux from the pole pieces at the ends of the magnet attracts each top roll toward the bottom roll shaft with the proper weight or pressure. When the cross section of the steel shell of the top roll is made thin enough, magnetic saturation is readily achieved and a condition of reluctance is created whereby the loss due to leakage through the shell from pole piece to pole piece is minimized. Highly oriented magnets like those sold under the name ALNICO V have been found to be eminently satisfactory in rolls according to this invention even though such magnets are relatively low in mechanicalor structural strength. The thin tubular sleeve of magnetic steel provides the necessary structural strength without, however, producing objectionable iiux loss due to leakage, and constitutes the sole element supporting and holding together the magnet, p ole pieces and roll-supporting gudgeons. Note that the shell is of uniform cross-section through its length, having no weak spots.

This basic roll construction lends itself also to the use of more than one magnet, and a plurality of magnets can be used aligned end to end as shown in FlGS. 2 and 3, making it possible to employ magnetic weighted rollers of small diameter but of great length. In the form of FIG. 2, for example, a single elongated top roll ltb, shown in detail in FlG. 5, is provided with a rubber or similar resilient cot or covering 14h extending its full length. Gudgeons 2Gb and end pole pieces ZltrareV provided, closing the ends of a thin steel tube or sleeve 3% in which a plurality of magnets 28a are closely fitted. The p ole` pieces are secured Within the shell as at 3412 in some suitable fashion such as was previously mentioned in connection with the embodiment shown in FIGS. l and 4. Between the ends of the several magnets in this roll an intermediate pole piece 2da is mounted, such intermediate pole pieces being in the form of a disk closely iitting the tube and against the magnet ends, the adjacent poles of the magnets in the roll both being of the same polarity so that a series of magnetic elds is provided along the roll.

In this form, the drive shaft or bottom roll 12b, shown in detail in FIG. 6, may be made of magnetic steel as in the first form illustrated and described but with the liuting 16h extended for the entire length of the roll to match the full length cot 14h on the top roll. However, and indicating that magnets may be used in the bottom roll as well as in the top roll, magnets 28h may be provided in the bottom roll as shown, these magnets being closely surrounded by a thin walled steel shell 32h on which the tintes lob are formed or provided. End pole pieces 24h are secured to the drive shaft ends 12b, as at 34C in a suitable fashion such as was previously described in connection with the other embodiments, and an intermediate pole piece 26h in the bottom roll is positioned opposite corresponding pole piece 26a in the top roll when a plurality of magnets is used in both the bottom and top roll. As shown, the polarity position of the magnets in the bottom roll is reversed from that of the magnets in the top roll in this double magnetic roll assembly and greatly increased pressures or weights may be obtained with this arrangement.

As may be seen from FlG. 3 it is further possible to use the basic steel sleeve construction as described above for calender or compression rolls where a hard, smooth outer roll surface is desired. Accordingly, the form of invention illustrated in FIG. 3 includes a bottom roll or shaft 12C containing magnets 23e, end pole pieces 24e and an intermediate pole piece 26C, all manufactured and assembled like the bottom roll of FIG. 2, but without any fluting on the outside of the steel shell 32e. Cooperating with this magnetic bottom roll is a smooth hard surfaced top roll lil@ which may be made of solid Steel with gudgcons Ztlc. Alternatively this top roll might be a shell, provided with internal magnets and pole pieces in much the same fashion as the top roll of FiG. 2, but Without a resilient covering or cot.

It will be apparent that the invention may be applied to roll sets where either the top or bottom roll or both rolls contain magnets. It also should be understood that resilient cots may be employed and the steel sleeve or tubing containing the magnets can carry iiutings of known cross section to increase the grip, but plain surfaces also may be provided. Although there is a certain leakage iux through the steel tubing from pole piece to pole piece, if the wall of the tubing is thin enough and is magnetically saturated, the permeability of the sleeve is lowered and makes available a high percentage of useful flux for attracting either nonmagnetized ferrous or magnetized companion rolls.

Another interesting phenomenon is exhibited by magnetic rolls according to this invention. That is, the magnetically saturated steel shell around the magnet makes the roll less sensitive to demagnetization. In other words adjacent magnetic fields will have less effect on rolls of the present invention than on rolls of more conventional design.

As will be evident from the foregoing description, certain aspects of this invention are not limited to the particular details set forth as examples, and it is contemplated that various and other modifications and applications of the invention will occur to those skilled in the art. It is therefore intended that the appended claims shall cover such modifications and applications as do not depart from the true spirit and scope of the invention.

What is claimed as new and is desired to be secured by Letters Patent of the United States is:

1. In a magnetic pressure roll set comprising a first roll with cylindrical permanent magnet means therein,

magnetic pole pieces at the ends of the magnet,

a hollow cylindrical outer shell of uniform cross-section closely surrounding and enclosing said magnet and pole pieces,

means rotatably mounting said first roll, and

a second roll of magnetic character rotatably mounted next to said first roll for pressure-creating cooperation therewith by influence of magnetic liuX from the said magnet and pole pieces of said first roll,

that improvement in which said shell in said first roll is of magnetic material of such thin cross-section that said permanent magnet means maintains said shell in magnetically saturated condition, suflicient reluctance thereby being pro,- vided minimizing magnetic flux loss from pole piece to pole piece and said shell containing said magnet and pole pieces and constituting structural support of the same in said roll and of said roll in its mounting.

2. That improvement in a magnetic pressure roll set as claimed in claim l in which the magnetic material of said shell is steel.

3. That improvement in a magnetic pressure roll set as claimed in claim 1 wherein the means rotatably mounting said first roll comprises a pair of gudgeons integral with said pole pieces at the ends of said roll.

4. A roll set as claimed in claim 1 in which said rolls are drafting rolls and one said roll carries an annular resilient cot thereon,`

while said other roll is provided with a iinely fluted section opposite said cot to cooperate therewith in drafting material passing between said rolls.

5. A roll set as claimed in claim 1 in which said rolls are calendering rolls and both rolls are provided with cooperating hard, smooth outer surfaces to calender material passing between said rolls.

6. A magnetic pressure roll for the purposes described comprising an outer hollow cylindrical shell of uniform thin crosssection,

permanent magnet means including at least one cylindrical magnet closely fitted within said outer shell,

a pair of soft steel pole piece disks of the same diameter as said cylindrical magnet fitted within and closing the ends of said shell, bearing tightly against the ends of said magnet and means securing said pole piece disks within the ends of said shell and holding said magnet tightly in the shell between the disks,

said shell constituting structural support of said magnet and pole piece disks in the shell and being of ferromagnetic material of such said uniform thin crosssection that said permanent magnet means maintains said shell in magnetically saturated condition, suicient reluctance thereby being provided minimizing magnetic flux loss from pole piece disk to pole piece disk in the shell. f

7. A pressure roll as claimed in claim 6 in which said magnetic means comprises a plurality of cylindrical magnets closely fitted end to end within said outer shell with a soft steel pole piece disk between the ends of adjacent magnets.

8. A pressure roll as claimed in claim 6 including a pair of outwardly extending gudgeons, one on each of said pole piece disks, for rotatably supporting said roll at its ends.

9. A pressure roll as claimed in claim 8 in which each of said gudgeons is formed integrally with a said pole piece disk.

10. In a magnetic pressure roll set comprising a iirst roll with cylindrical permanent magnet means therein,

magnetic pole pieces at the ends of the magnet,

means rotatably mounting said rst roll, and

a second roll of magnetic character rotatably mounted next to said first roll for pressure-creating cooperation therewith by influence of magnetic flux from the said magnet and pole pieces of said rst roll,

that improvement in which said shell in said first roll is of ferrous material of such thin cross-section that said permanent magnet means maintains said shell in magnetically saturated condition, sucient reluctance thereby being provided minimizing magnetic flux loss from pole piece to pole piece and said shell containing said magnet and pole pieces and constituting the sole structural support of the same in said roll and of said roll in its mounting.

References Cited in the le of this patent UNITED STATES PATENTS 2,686,940 Burnham Aug. 24, 1954 2,951,266 Burnham Sept. 6, 1960 3,079,646 Burnham Mar. 5, 1963 FOREIGN PATENTS 878,256 Great Britain Sept. 27, 1961

Claims

10. IN A MAGNETIC PRESSURE ROLL SET COMPRISING A FIRST ROLL WITH CYLINDRICAL PERMANENT MAGNET MEANS THEREIN, MAGNETIC POLE PIECES AT THE ENDS OF THE MAGNET, A HOLLOW CYLINDRICAL OUTER SHELL OF UNIFORM CROSS-SECTION CLOSELY SURROUNDING AND ENCLOSING SAID MAGNET AND POLE PIECES, MEANS ROTATABLY MOUNTING SAID FIRST ROLL, AND A SECOND ROLL OF MAGNETIC CHARACTER ROTATABLY MOUNTED NEXT TO SAID FIRST ROLL FOR PRESSURE-CREATING COOPERATION THEREWITH BY INFLUENCE OF MAGNETIC FLUX FROM THE SAID MAGNET AND POLE PIECES OF SAID FIRST ROLL, THAT IMPROVEMENT IN WHICH SAID SHELL IN SAID FIRST ROLL IS OF FERROUS MATERIAL OF SUCH THIN CROSS-SECTION THAT SAID PERMANENT MAGNET MEANS MAINTAINS SAID SHELL IN MAGNETICALLY SATURATED CONDITION, SUFFICIENT RELUCTANCE THEREBY BEING PROVIDED MINIMIZING MAGNETIC FLUX LOSS POLE PIECE TO POLE PIECE AND SAID SHELL CONTAINING SAID MAGNET AND POLE PIECES AND CONSTITUTING THE SOLE STRUCTURAL SUPPORT OF THE SAME IN SAID ROLL AND OF SAID ROLL IN ITS MOUNTING.