Conditioning arrangement for open-end friction spinning machine

An open-end friction spinning machine is disclosed which has a plurality of adjacently arranged spinning units, each spinning unit including two adjacently arranged friction rollers driven in the same rotational direction and forming a wedge-shaped yarn forming gap therebetween. At least the friction roller rotating out of the wedge-shaped gap exhibits a closed cover surface. To assure consistent predetermined yarn characteristics, friction roller conditioning devices are disclosed for conditioning the friction surfaces of the friction rollers with closed cover surfaces.

BACKGROUND AND SUMMARY OF THE INVENTION 
The invention relates to an open-end friction spinning machine with a 
plurality of adjacently arranged spinning positions which each include two 
adjacently arranged friction rollers driven in the same rotational 
direction and forming a wedge-shaped gap of which at least one of the 
friction rollers rotates out of the wedge-shaped gap and exhibits a closed 
coating or cover surface. 
An open-end friction spinning aggregate is described in German Published 
Unexamined Patent Application (DE-OS) 29 43 063 wherein the rollers 
rotating out of the wedge-shaped gap exhibit a closed cover or coating 
surface, while the roller rotating towards or into the wedge-shaped gap 
includes a perforated coating surface and a suction device within its 
interior region which is directed towards the wedge-shaped gap. In certain 
cases, an open end friction spinning machine is constructed from a 
plurality of such spinning units. The roller displaying a closed cover 
surface includes a coating or a layering of an elastic material, for 
example, natural or synthetic caoutchouc (India rubber). By using a roller 
with a closed cover surface, the structural costs are reduced since in 
such cases a second suction device becomes unnecessary and especially 
because the second roller would not need a perforation requiring 
substantial manufacturing expenditures. Practical tests, however, have 
shown that with such a device the quality of the yarn experiences 
substantial fluctuations, whereby a change in quality may result after 
relatively short or longer periods of time. 
The invention is based upon the problem to so design an open-end friction 
spinning machine of the kind mentioned above so that a yarn of a 
consistent quality can be obtained. 
This problem is solved according to the invention by providing one or 
several devices for the conditioning of the surfaces of at least those 
rollers with closed cover surfaces. 
The invention is based, at least in part, on the knowledge established 
through tests that the change of yarn quality is caused by a substantial 
change in the friction characteristics of the rollers with closed cover 
surfaces, which surfaces preferably contain a non-metallic layer. Through 
the device or devices for conditioning the surfaces according to the 
present invention, constant friction characteristics of the rollers are 
obtained which then lead to a constant yarn quality. 
According to a first preferred embodiment of the invention it is provided 
that each spinning unit is equipped with a device for conditioning the 
surfaces of the rollers with closed coating surfaces. These devices are 
preferably continuously driven so that the friction characteristics remain 
consistently constant. An electrostatic charge of the roller surfaces is 
advantageously avoided, for example, by providing the devices with a 
metallic conductor adjacent to the roller surfaces which is grounded. 
In most cases, it is sufficient in practice according to other preferred 
embodiments of the invention to provide periodic conditioning of the 
surfaces of the rollers. According to one preferred embodiment it is 
provided that the roller conditioning devices of these spinning units are 
jointly operable by means of a central drive. Accordingly, another 
preferred embodiment is provided wherein the roller conditioning devices 
of the individual spinning units are selectively switched into operation 
by means of a maintenance device movable alongside the spinning machine. A 
central drive is thereby made unnecessary since activating the devices is 
assumed by the maintenance device which in most cases is already present 
for other machine maintenance operations. 
According to another embodiment of the invention a maintenance device which 
is movable along the spinning machine is provided, the same being movable 
to the respective individual spinning units and including a device for 
conditioning the surfaces of at least the rollers with closed coating 
surfaces. According to certain preferred arrangements, it is provided that 
the movable maintenance device passes to the single spinning units in a 
predetermined time interval. Alternatively or in addition to this 
arrangement, preferred embodiments are contemplated wherein the movable 
maintenance device attends to a conditioning of the surfaces during a yarn 
break, or during a spool exchange, or prior to a start spinning after a 
machine operational stand still. 
In certain embodiments of the invention it is provided that the device for 
conditioning includes a cleaning device movable to the surfaces of the 
rollers with closed shell surfaces. In many cases the cleaning alone 
already results in maintaining constant friction characteristics since 
thereby also the contaminations are removed which are carried by the 
supplied fibers, as for example dust, waxes or greases, or the like which 
will stick to the closed shell or cover surfaces and especially in the 
pores thereof. Cleaning devices are herewith contemplated having 
brush-like or scraping elements. It is also contemplated according to the 
invention to utilize cleaning devices which clean the surfaces of the 
rollers with a fluid or liquid cleaning detergent. 
In certain preferred embodiments of the invention it is provided that the 
device for conditioning includes apparatus for applying a coating or layer 
covering the surfaces of the rollers at least in the area of the yarn 
formation region. These coatings or layers which are applied in the form 
of fluids or pastes, then determine the friction characteristics. Since 
these coatings wear out during the spinning operation, they have to be 
renewed from time to time according to the invention. It can thereby be 
advantageous to connect the application of such layers with a prior 
cleaning process at the surfaces of the rollers. 
In certain preferred embodiments of the invention it is provided that the 
device for conditioning includes apparatus for roughening the surfaces of 
the rollers with closed cover surfaces. With such a roughening the 
surfaces of the rollers are brought into a desired, predetermined 
condition affecting the friction characteristics, which condition, 
especially through wear, will get less effective with a longer operational 
time period, and therefore has to be renewed at least from time to time 
according to the invention. It is advantageous according to certain 
preferred embodiments of the invention to combine this roughening with a 
prior cleaning and/or a prior application of a coating. 
In certain embodiments of the invention it is provided that the device for 
conditioning includes apparatus for repair works and/or applying of 
impressions upon the surfaces of the rollers with closed shell surfaces. 
It is thereby taken into account that the surfaces will change through the 
wear, dependent upon the operational periods. Here again it is 
advantageous according to certain embodiments of the invention to also 
accommodate a combination of a cleaning process and/or application of a 
coat and/or a roughening process. 
In certain embodiments of the invention it is provided that the device for 
conditioning includes apparatus for polishing the surfaces of the rollers 
with closed cover surfaces. Also by means of this arrangement, a certain 
consistent surface quality is obtained through which the friction 
characteristics are influenced in a predetermined manner. This polishing 
process may especially be connected with a prior, or also with a 
subsequent cleaning process according to the invention. It is also 
contemplated to attend to the polishing process after the application of a 
layer or coat. 
Further objects, features, and advantages of the present invention will 
become more apparent from the following description when taken with the 
accompanying drawings which show, for purposes of illustration only, 
embodiments in accordance with the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS 
The open end friction spinning machine constructed in accordance with FIGS. 
1 through 3 includes a plurality of adjacently arranged spinning units 3, 
which each are supplied with a fiber band 5 to be spun out of a can or 
bucket 4. The spinning units 3 twist the fiber band 5 to a yarn 6 which is 
drawn off by means of a yarn withdrawal device 7 and wound upon a take-up 
spool 9. The take-up spool 9 is driven by a grooved drum 8 and held by a 
pivotable bar or retainer 19 (FIG. 2). 
Bearing housings 15 are arranged for each spinning unit at a machine frame 
14, in which housing friction rollers 18 and 18' are housed. The rollers 
18 and 18' are positioned parallel to each other to form a wedge-shaped 
gap 29 (FIG. 3) to which single fibers are supplied via a not further 
illustrated inlet and opening device. The single fibers are twisted to the 
yarn 6 within the wedge-shaped gap 29. Yarn 6 is drawn off in the 
longitudinal direction of the wedge-shaped gap 29 by means of the yarn 
withdrawal device 19. The rollers 18 and 18' are borne in a not further 
illustrated manner within the bearing housing 15. The rollers 18 and 18' 
are driven in the same rotational direction (arrow directions C and B of 
FIG. 3) by a moving tangential belt 26 (arrow direction A) engaging 
directly against their coating or cover surfaces. This tangential belt 26 
drives all rollers 18 and 18' of the spinning units 3 at one machine side 
in a corresponding manner. Roller 18' rotating into the wedge-shaped gap 
29 is arranged as a so-called suction roller, which means it exhibits a 
perforated shell surface and includes a suction insert 30 in its interior 
connected to a sub-pressure source, which suction insert 30 includes a 
suction slit 31 limited by protrusions which extend closely up to and 
adjacent the inner surfaces of roller 18'. Said suction slit 31 is 
directed towards the wedge-shaped gap 29 and also to the opening 28 of the 
fiber-feed channel 27. A suction air stream is thereby produced which 
holds the supplied fibers, as well as the forming yarn 6 in the 
wedge-shaped gap. Additionally the fiber transport in the fiber-feed 
channel 27 is at least supported by this suction air stream. The roller 18 
rotating out of the wedge-shaped gap 29 (arrow direction C) displays a 
closed shell surface. This closed shell surface preferably includes a 
layer of synthetic material, especially a coat of synthetic or natural 
caoutchouc (rubber). For example, a coat or layer made from a material 
which is commonly known under the trademark "Vulkollan" has proven to be 
favorable. 
The rollers 18 and 18' are covered by a cover-like housing part 16 at the 
side of the wedge-shaped gap 29 which serves as the yarn formation region. 
This housing part 16 also includes the fiber-feed channel 27. This 
cover-like component 16 includes prismatic longitudinal grooves 33 
arranged at the bearing housing which support themselves and are centered 
by cylindrical guide rails or tracks 32. 
The maintenance device 2, which is guided by wheels 12 and 13 at rails 10 
and 11, is provided with a device 23 pivotable about an axle 24 which 
device, for example, consists of a hydraulic or pneumatic press which is 
carried by means of a roller head 25 linked into a corresponding counter 
element of the cover-like housing part, and through which the housing part 
16 is pivotable about an axle into the position illustrated in FIG. 2 by 
dotted lines. The rollers 18 and 18' are thereby exposed. Additionally, 
the maintenance device 2 is provided with a device 20 for conditioning the 
surfaces of the roller 18 displaying a closed shell surface. This 
conditioning device is arranged by means of a device pivotable about an 
axle 22, for example, again a pneumatic or hydraulic press and movable to 
the opened spinning unit and the rollers 18 and 18'. 
In order to condition the entire circumference, especially of roller 18, 
the same has to rotate during the conditioning process. In order not to 
have to operate with the relatively high spinning operational rotational 
speeds, the device 20 is provided with means for interrupting the 
operational drive, and with an auxiliary drive for the rollers 18 and 18'. 
The device 20 (FIG. 4) which is movable to and from the rollers 18 and 18' 
corresponding to the arrow direction D and E, is provided with two 
lift-off rollers 38 and 39 arranged upon levers or holders 36 and 37, by 
means of which the tangential belt 26 is moved off rollers 18 and 18'. The 
device 20 additionally includes a friction wheel 41 driven in arrow 
direction F which is movable to the two rollers 18 and 18' in the area of 
the wedge-shaped gap 29 upon a lever or holder 40. The drive direction of 
the friction wheel 41 is chosen in such a manner that the operational 
drive direction for the rollers 18 and 18' is also retained by the 
auxiliary drive. 
The device 20 can contain further devices for conditioning the surface of 
roller 18, such as in accordance with the preferred embodiments of FIGS. 5 
through 9 described below. 
The device 20 (FIG. 5) is held at the bearing housing 15 by means of 
supports 42 which include prismatical guides 43 supported upon the 
cylindrical bars or tracks 32 of the bearing housing 15 and are thereby 
centered. A leaf-shaped spring-elastic strip 44 is attached to a pipe 47 
by means of clamps 46, which strip 44 is elastically bent and lays upon 
the roller 18 with one side surface. The side of the leaf-shaped elastic 
strip facing or laying upon the surface of the roller 18 includes a 
friction layer or coat by means of which roller 18 is roughened at its 
surface while it is rotating in arrow direction C. At the pipe or duct 47 
extending in the axial direction with respect to roller 18, several 
adjacently arranged jets 48 are provided for applying a treatment liquid 
or fluid upon the leaf-shaped elastic strip 44 and subsequently upon the 
surface of roller 18. A cleaning solution or liquid is supplied, for 
example, via the pipe or duct 47, which cleaning solution flushes away the 
particles loosened from the coat of the roller 18 during the roughening 
process. In a similar manner a paste-like or fluid means can be applied to 
the surface of the roller which itself hardens quickly and is distributed 
evenly by means of the leaf-like elastic strip. 
In the embodiment according to FIG. 6 a plurality of flexible plastic 
strips 54 are fixedly attached to a bar or track 53 of the device 20A, 
which strips 54, similar to the leaf-shaped elastic strip 44 in FIG. 5, 
lay against the surface of roller 18A when device 20 is activated and 
moved in the direction of Arrow D. The roller 18A thereby consists of a 
tube 51 upon which a plastic layer 52 is pressed. The roller 18A is driven 
by tangential belt 26 rotating counter-clockwise to the coat or layer 52, 
which tangential belt is loaded by a friction roller 49 upon which the 
return driven run 50 of the tangential belt is reverse guided. The device 
20A is additionally provided with a plurality of adjacently arranged 
application jets 48 in the longitudinal direction of the roller 18 through 
which a fluid or paste-like treatment means is supplied via a channel 
system 55. With this embodiment, a liquid or paste-like treatment means is 
supplied which not only dries quickly but also hardens, which again is 
distributed evenly to a determined thickness by the flexible plastic 
strips upon the surface of the roller 18A. It is thereby provided that the 
device 20A is driven to a changed motion corresponding to arrows G and H 
so that the entire axial length of the roller 18A is evenly conditioned. 
With the embodiment according to FIG. 7, the device 20B includes a 
plurality of spring-like steel fingers or steel brushes 57 attached to a 
rake 56 for the conditioning process. Rake 56 is movable with respect to 
roller 18 corresponding to arrows E and D and is driven in a back and 
forth motion corresponding the arrows G and H. By means of these steel 
fingers or brushes 57 scratching the surface of roller 18B, the surface is 
cleaned and roughened in a desired manner. For example, the device 20B 
according to FIG. 7 could also be arranged at each spinning unit, 
especially at the side facing away from the fiber feeding or guiding 
wedge-shaped gap. This device can then also be moved with respect to the 
rollers 18 as depicted by arrows E-D and F-H as the need arises during the 
normal spinning operation. These motions are controlled simultaneously by 
a drive common to all spinning units at one machine side. In certain 
preferred embodiments, the rake is designed with a length which 
corresponds at least to the operable yarn formation zone axial length of 
the roller 18B, which means especially the opening area of the fiber-feed 
channel and also the then following yarn treatment zone through which the 
yarn being produced is drawn off. With such a construction the back and 
forth (arrows G and H) moving drive is made unnecessary. 
With the embodiment according to FIG. 8, a roller 18C is provided 
containing a closed cover or shell surface. Said surface is composed of a 
plurality of friction disks 58 between which intermediate rings 59 made 
out of metal are arranged respectively and which are stuck jointly upon an 
axle and held between face disks 60. The intermediate rings 59 exhibit a 
smaller diameter than the friction disks 58 so that only the friction 
disks 58 come into contact with the fibers and the yarn. Therefore only 
the friction disks are to be conditioned. A device 20C is provided for 
facilitating a polishing of the outer surfaces of the friction disks 58. 
The device 20C includes a roller 61 with a soft surface, a so-called mop 
roller, the axle 62 of which is borne in a holder or retainer 63 and is 
rotatably driven via a drive wheel 64 by means of a cord or rope. The 
roller 61 is soaked or impregnated with a polishing means, for example, an 
abrasive polishing paste which is guided to roller 61 via an application 
jet 66. The applicator jet 66 is driven in a back and forth motion as 
depicted by arrows I and K so that the abrasive paste is evenly 
distributed. Additionally, the device 20C which is moved to and away from 
the roller 18C as depicted by arrows D and E, is also driven in the 
direction of arrows G and H to a back and forth motion axially parallel 
with the roller 18C. Roller 61 extends parallel to roller 18C. 
The device 20D according to FIG. 9 includes a rope or cord 67 as a means 
for conditioning the surface of roller 18D (and also the roller 18'), 
which cord is inserted in the wedge-shaped gap between the two rollers 18 
and 18' during positioning movement of the device 20D in the direction of 
arrow D. The cord or rope preferably can consist of a wire which is 
supplied with wire brushes so that the same is suitable for cleaning and 
roughening of the surface, especially the surface of roller 18 containing 
a coating. The cord or rope 67 is guided about two deflection rollers 70 
and 71 in such a manner that the same is guided in the longitudinal 
direction of the wedge-shaped yarn forming gap. The ends of the cord 67 
are attached to two wheels 68 and 69. The wheel 68 is driven in a back and 
forth motion as depicted by arrows L and M. The wheel 69 is loaded with a 
tension spring so that the treatment part is pulled back and forth in the 
wedge-shaped gap corresponding to arrows G and H whereby the tension 
spring of wheel 69 is responsible for constantly straightening and 
tensioning the treatment cord 67. 
The device 20D here additionally includes two application devices 72 and 73 
which the treatment cord 67 extends through by which a treatment means 
especially in the form of a paste or a wax, is supplied to the treatment 
cord 67. The device 20D according to FIG. 9 is preferably a component part 
of a movable maintenance device and is positioned adjacent respective 
spinning units in a manner corresponding to the other treatment devices 
described above, either in a constant time interval and/or after a yarn 
break and/or during a spool exchange and/or prior to a start spinning of 
the spinning machine from the stand still position. It is, however, also 
contemplated to provide for such a device 20D in accordance with FIG. 9 
for each spinning unit respectively, which is then put into operation by a 
central drive at all spinning units jointly or by a maintenance device 
passing the spinning units. It is also contemplated to hold the device 20D 
in a constant operation at each spinning unit, especially if a treatment 
cord or rope 67 is provided which is not meant for roughening the surface 
of rollers 18D and 18', but is arranged to apply a coating determining the 
friction affect. 
Although the present invention has been described and illustrated in 
detail, it is to be clearly understood that the same is by way of 
illustration and example only, and is not to be taken by way of 
limitation. The spirit and scope of the present invention are to be 
limited only by the terms of the appended claims.