Magnetic roller

A magnetic roll for use in roller pairs of a drafting system on a textile machine. Each magnetic roll includes a central pole member having a rare earth magnet positioned on either side thereof. An end pole member is provided adjacent each magnet, and a cot is provided next to each end pole member for gripping and propelling fibers between the roller pairs of the drafting system.

BACKGROUND OF THE INVENTION 
This invention relates generally to a magnetic roller for use in the 
drafting system of a textile machine, such as a spinning machine, roving 
machine, drawframe, card machine, or the like. 
In drafting fibers on a textile processing machine, such as a spinning 
machine, a band of fibers is passed between at least two pairs of rollers, 
the second, downstream, pair of rollers being driven at a faster rate than 
the first, upstream, pair of rollers such that the band of fibers becomes 
elongated, or "drafted" between the two pairs of rollers. A typical 
drafting system may include two pairs of such cooperating rollers or 
additional pairs of rollers to form successive drafting zones 
therebetween. 
In order to draft the fibers, pressure must be applied between the rollers 
in each roller pair in a manner sufficient to cause the nip zone at the 
interface between the roller pair to both grip and propel the fibrous 
material. Weights, springs, levers, hydraulic, pneumatic or other pressure 
systems for forcing the rollers towards one another have been used in the 
past. However, a drawback of such systems is that they require substantial 
supporting structures to counteract the external weighting applied to the 
rollers. The supports must be strong enough to prevent undesirable 
deflection in the rollers being weighted. Also, bearings must be included 
which can both support the rollers for rotation and withstand the forces 
delivered by the external weighting. 
As an alternative to the external weighting, magnetic weighting can be 
used. In magnetic weighting, at least one roll of each roller pair is 
magnetized such that it is attracted to the other roll of the pair, which 
is constructed of either a ferrous material or a magnetic material. In 
this system, the magnetic force between the rollers pulls the rollers 
together and applies sufficient pressure therebetween to grip and propel 
the fibers being processed. No additional weights, springs, levers, 
hydraulic or pneumatic systems are required for weighting the rollers. By 
eliminating the need for such weighting systems, the corresponding roller 
support structures can be simplified since roller deflection is 
essentially eliminated. Also, the bearing systems for the rollers will not 
have to withstand the externally-delivered forces caused by other types of 
weighting. 
In some magnetic roller designs, the magnets are carried internally within 
the rollers and are contained within cylinders or sleeves. The shells are 
typically constructed of a non-magnetic material. With such magnetic 
roller designs, the magnets and corresponding pole members for the magnets 
are typically rotatably supported on gudgeons or journals. 
Further, prior magnetic rollers were limited by the amount of magnetic 
force which could be delivered, due to the composition of the magnets 
used. Because of the type of magnets used and the diameter of the magnets 
required to achieve the necessary attractive force, a shorter, and 
therefore a more desirable, draft zone was not achievable between adjacent 
roller pairs. Additionally, prior magnetic rollers were prone to 
de-magnetization over time and could actually be de-magnetized if the 
rollers were not inserted and oriented properly with respect to adjacent 
rollers. 
Prior magnetic roller designs include U.S. Pat. No. 3,134,057, issued to 
Tsunoo, et al, which discloses a magnetic roller having magnetic pieces 
fitted on pole rings. U.S. Pat. No. 3,150,419, issued to Aurich, discloses 
magnetic rollers having conventional magnets carried within a roll and 
housed by a metal sleeve. The magnets are separated by pole pieces, and 
gudgeons are used for supporting the rollers for rotation. German Patent 
document No. 1,185,961, discloses a magnetic roller having magnet rings 
adjacent to one another and iron pole pieces located adjacent to and 
outboard of the magnet rings. U.S. Pat. No. 3,457,618, issued to O'Neal, 
discloses a magnetic crush roll for use with a carding machine, the roll 
including magnetic modules carried on a shaft. U.S. Pat. Nos. 3,364,545 
and 3,605,229, also disclose magnetic crush rolls. 
U.S. Pat. No. 4,829,277, issued to Stahura, et al, and U.S. Pat. No. 
5,055,812, issued to Abele, et al, both disclose magnetic resonance 
imaging devices used in the medical field. Each of the patents disclose 
the use of rare earth magnets of neodymium, iron, and boron alloy 
compositions. 
While prior magnetic roller designs are available, they present limitations 
which may prevent desirable roller pressure interfaces being achieved 
between rolls of drafting roller pairs and also draft zones of minimum 
lengths. 
SUMMARY OF THE INVENTION 
It is the principal object of the present invention to provide a magnetic 
roller for use in a textile drafting system which allows for an increased 
gripping force between pairs of drafting rollers. 
It is a further object of the present invention to provide a magnetic 
roller which allows for a draft zone of minimum length. 
It is another object of the present invention to provide a magnetic roller 
which does not tend to de-magnetize over time. 
It is still another object of the present invention to provide a magnetic 
roller which can be oriented in either of two directions. 
It is still another object of the present invention to provide a system for 
forcing drafting roller pairs together without using springs or other 
systems for externally delivering pressure or weighting. 
It is yet another object of the present invention to provide a drafting 
roller pair system which minimizes bottom roller deflection and bearing 
structural requirements. 
Further, another object of the present invention is to provide a magnetic 
roller of minimum diameter. 
These and other objects and aspects of the present invention will become 
further evident upon reference to the following drawings and accompanying 
specification. 
Generally, one embodiment of the present invention includes a magnetic 
roller for use in conjunction with a driven roller of a drafting roller 
pair of a textile drafting system. The magnetic roll comprises at least 
one rare earth magnet and at least one resilient member associated with 
the rare earth magnet for engaging the driven roller of the textile 
drafting system. Such a roll would also include support means associated 
with the rare earth magnet and the resilient member for substantially 
coaxially supporting the magnet and the resilient member together for 
rotation in the textile drafting system. 
A preferred embodiment of the present invention includes a magnetic roller 
for use in a textile drafting system of a spinning machine, roving 
machine, drawframe, card machine, or the like, comprising at least one 
substantially cylindrical central pole member having a first side and a 
second side opposite the first side. The central pole member defines a 
central pole member aperture therein. A first substantially cylindrical 
rare earth magnet is provided adjacent to the first side of the central 
pole member, and a second substantially cylindrical rare earth magnet is 
positioned adjacent to the second side of the central pole member. Each of 
the first and second rare earth magnets define an aperture therein. 
Also provided is a first end pole member adjacent to the first rare earth 
magnet and opposite the first side of the central pole member. A second 
end pole member is provided adjacent to the second rare earth magnet and 
opposite the second side of the central pole member, each of the first and 
second end pole members defining an aperture therein. 
An elongated shaft is also provided which passes through each aperture of 
the central pole member, the first and second rare earth magnets and the 
first and second end pole members, for maintaining the central pole 
member, the first and second rare earth magnets, and the first and second 
end pole members in substantially coaxial alignment with respect to one 
another. 
More specifically, the magnetic roll of the present invention includes the 
pole members being individually greater in width, or mass, than either of 
the first and second rare earth magnets. Also, the rare earth magnets are 
preferably of a neodymium-iron-boron composition.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the drawings in detail, wherein like reference characters 
represent like elements or features throughout the various views, the 
magnetic roller of the present invention is designated generally in the 
Figures by a reference character 10. 
Referring to FIG. 1 of the drawings, the magnetic roll system of the 
present invention is illustrated in a drafting system 1 for a spinning 
machine. The drafting system as shown in FIG. 1 includes four drafting 
roller pairs, generally 12, one pair 14 being shown in phantom, and 
includes slivers or rovings 16 entering through condensers or trumpets 18 
and into a first roller pair 20 which includes a magnetic roller 10 
constructed in accordance with the present invention. Magnetic roller 10 
is attracted to a ferrous bottom roller 22, preferably constructed of 
steel, which may extend the length of the spinning machine or through 
several sections of the spinning machine. Each roller pair 12 includes an 
upper roller, generally 26, which is preferably a magnetic roller 10, and 
a lower roller 22. 
Generally the lower roller 22 is driven while the upper roller 26 rotates 
through frictional interaction with the lower roller 22 brought about 
through the magnetic attraction of the upper roller 26 to the lower roller 
22. Preferably, attached to the ends 24 of alternating upper rollers 26 
and bottom rollers 28, are apron belts 30 which are propelled about 
carriers 32 by the rotation of the upper and lower rollers 26, 22. Use of 
belts 30 allows for a further reduction of the drafting zone length as the 
belts 30 allow fibers to be delivered and released closely adjacent to the 
nip zone of the succeeding downstream roller pair 12. 
The upper roller 26 is carried for rotation through engagement of the ends 
of a support means or member such as a shaft 34, preferably constructed of 
non-magnetic steel, such as stainless steel, or other non-magnetic 
material, which passes through the entire length of each magnetic roller 
10 and which extends outwardly from each end thereof. A holder which 
engages the ends of the shaft 34 is not shown, but could be of 
conventional design. 
As illustrated in FIGS. 1 and 2, each magnetic roller 10 includes a 
substantially cylindrical central pole member 36, having an aperture 37 
extending therethrough, centrally located along the length of the shaft 
34. Positioned adjacent to and on either side of the central pole member 
36 is a rare earth magnet 38, 40 constructed in accordance with the 
present invention. Each magnet 38, 40 is preferably of 
neodymium-iron-board composition, although a variety of other rare earth 
magnet compositions could also be used, and it is to be understood that 
the composition of the rare earth magnet is not to be limited to such a 
neodymium-iron-boron composition. 
Each magnet 38, 40 defines a centrally located aperture 42 extending 
therethrough for receipt of the shaft 34. Positioned adjacent to each 
magnet, opposite the central pole member 36, are first and second end pole 
members 44, 46. The end pole members 44, 46 are also of cylindrical shape 
and have a hole 48 passing through the center thereof. The end pole 
members are preferably of slightly larger diameter than the magnets 38, 
40, although they could be of greater, less or equal diameter, if desired. 
The central pole piece 36 and the end pole pieces 44, 46 are preferably 
constructed of steel, although other suitable ferrous or 
magnetic-attractive materials could also be used. 
Positioned adjacent to each end pole piece 44, 46 is a cylindrical spacer 
50, preferably constructed of a non-ferrous material such as aluminum, 
onto the surface of which a resilient member such as a rubber cot 52 is 
provided for rolling engagement with engagement portions 54 of the lower 
steel roll 22. The fibers being drafted are gripped and propelled by cots 
52 the nip zone between the rubber cots 52 and the lower roll 22. Spacers 
50 are preferably press-fit to shaft 34 to retain spacers 50, pole members 
36, 44, 46 and magnets 38, 40 on shaft 34. 
Roving or sliver passing through the drafting system 1, exits the final 
pair of rollers, and is spun into a yarn 57 in a conventional manner on a 
rotating bobbin 58 acting in conjunction with a thread guide 60 and a 
conventional ring 62 and traveller 64 system. 
In one particular embodiment, the central pole member 36 is of greater 
width than the magnets 38, 40, which are each approximately the same width 
and diameter with respect to one another. Also in such embodiment, the end 
pole members 44, 46 are approximately the same width as the magnets 38, 
40. Further, while the end pole pieces 44, 46 and central pole members 36 
are approximately the same diameter, the central pole member 36 is 
preferably of a larger diameter than magnets 38, 40. While such a 
combination of dimensions has been found desirable, a variety of other 
widths and diameters of rare earth magnets and pole members could also be 
used to achieve satisfactory results. 
The magnetic rollers 10 of the present invention exert a much greater 
magnetic force as compared to the magnets used in prior designs. This 
allows for greater strength in gripping of the fibers being drafted and 
also allows for reduction in the diameter of the magnetic rolls 10 as 
compared to prior magnetic roller designs. By reducing the diameter of the 
magnetic rolls, the drafting roller pairs 12 can be placed closer to one 
another, to thereby shorten the drafting zones therebetween, which, 
accordingly, allows for greater drafting control. In one embodiment, it 
has been found that magnetic rollers having magnets and pole members of 
approximately 28 mm in diameter can be used, which is generally a smaller 
diameter than prior art magnetic rollers, while still delivering a 
significantly increased attractive force than was possible with the prior 
art magnetic rollers. However, magnets for top rolls having apron belts 30 
provided thereon can be of greater diameter than those rolls not having 
apron belts 30, while still providing favorable drafting. Also, magnets of 
larger diameters may find particular use in drafting systems such as those 
found on roving machines, draw frames, carding machines and the like. 
In the embodiment illustrated, the north poles of each magnet 38, 40 are 
adjacent to the central pole piece 36, and the south poles of each of the 
magnets 38, 40 are adjacent to the end pole pieces 44, 46, respectively, 
although other orientations of the magnets 38, 40 with respect to the 
other pole pieces could also be used. 
The shaft 34 passing through the magnetic roll 10 is preferably a constant 
diameter throughout its length. This is contrasted with prior magnetic 
roller designs, which were prone to de-magnetization, and which therefore 
had to be oriented in a specific relationship to prevent de-magnetization 
caused by adjacent magnetic rollers. To prevent improper orientation, some 
magnetic roller designs have used gudgeons of different diameters which 
would prevent the magnetic roller from being inserted in an improper 
orientation. Because the rare earth magnets used in the magnetic rolls of 
the present invention are not subject to de-magnetization, orientation of 
the rolls with respect to adjacent rolls is not critical, and therefore, 
the shaft 34 does not require ends of differing diameters. However, while 
shaft 34 has been shown for coaxially aligning pole to members 36, 44, 46, 
and magnets 38, 40 together, the apertures of the pole members 36, 44, 46, 
and magnets 38, 40 could be eliminated and half-shafts or gudgeons 
attached to spacers 50 used to support roller 10 instead. 
It is also to be understood that a variety of shapes of pole members 36, 
44, 46 and magnets 38, 40 could be used instead of the cylindrical shapes 
illustrated. Although roll 10 is shown having only two magnets and three 
pole members, a larger or smaller number of magnets and pole members could 
also be used to construct roller 10. Further, the diameters, widths, and 
masses of the magnets and pole members could be varied with respect to 
that disclosed to also achieve satisfactory results. 
For example, the central pole member and end pole members of each roll can 
be of greater or less width than the width of the magnets, depending on 
the space available on the roll and for the roll itself in the specific 
drafting application. Specifically, there may be embodiments where it is 
desirable to have pole members of lesser width and/or mass than the 
magnets. Also, because the spindle gauge of spinning machines can vary 
from one type of machine to another, the width relationship between the 
pole members and the magnets can vary depending on the particular gauge of 
spinning machine on which the rolls are used. It has been found that the 
pressure exerted between the rollers of the roller pairs, wherein at least 
one of the rollers is a magnetic roller constructed in accordance with the 
present invention, may be increased when the mass of the central pole 
member is greater than the mass of either of the magnets. Similarly, the 
pressure exerted can be increased by increasing the mass of the end pole 
members such that the mass of each of the end pole members is greater than 
the mass of the magnets. The increase in attractive force caused by 
increasing the mass of the pole members in relation to the magnets will be 
limited to a point, in that sufficient magnet mass must be present on the 
roller to provide at least a minimum threshold of attractive force and 
that the roller is of finite length, thereby placing inherent size 
limitations on the relationships between the pole members and the magnets. 
Another variation of the present magnetic roller design could include 
eliminating the central pole member altogether, using only the end pole 
members. Alternately, all pole members could be eliminated, with a single 
or series of magnets extending the length of the roll 10, or a portion 
thereof. Such a design could include resilient cots thereon for engaging 
the lower driven roller of a roller pair and the yarn in a nip zone formed 
therebetween. 
While preferred embodiments of the invention have been described using 
specific terms, such description is for present illustrative purposes 
only, and it is to be understood that changes and variations to such 
embodiments, including but not limited to the substitution of equivalent 
features or parts, and the reversal of various features thereof, may be 
practiced by one of ordinary skill in the art, without departing from the 
spirit or scope of the following claims.