Spinning station with operable cove for a rotor spinning machine

In a rotor spinning machine, each spinning station's drawing-in roller is connected directly to its own individual drive supported by the cover of the spinning station housing, which provides a simplified and conveniently accessible alternative to the conventional worm gear driving of the drawing-in rollers of the machine's plural spinning stations from a common drive shaft.

BACKGROUND OF THE INVENTION 
The present invention relates to the rotor spinning of textile yarns and, 
more particularly, to rotor spinning machines of the type having a 
plurality of simultaneously operated spinning stations each equipped with 
a driven spinning rotor, a driven sliver opening roller, and a driven 
drawing-in roller for feeding sliver to the opening roller, all of which 
are installed in a housing of the spinning station having an openable lid 
or cover to provide access to the functional parts. 
Conventionally, sliver is fed to the opening rollers at the spinning 
stations of rotor spinning machines via drawing-in rollers at each 
station, each drawing-in roller being connected via a worm gear to a 
common drive shaft extending along the entire spinning machine. Driving of 
the drawing-in rollers in this manner is known from published, 
non-examined German Patent Application DE-OS 27 21 386. If the yarn or 
sliver breaks, and during piecing up operations, the drawing-in roller is 
disconnected from the drive shaft by actuation of a coupling. Driving all 
the drawing-in rollers along one side of the spinning machine with a 
common drive shaft, and the provision of a coupling for each drawing-in 
roller, requires a considerable engineering expense and does not allow for 
individualized feeding of the slivers to be adjustably adapted to 
particular circumstances at the spinning stations. 
SUMMARY OF THE INVENTION 
It is therefore an object of this invention to provide a structurally 
simplified embodiment for driving the operational components of a spinning 
station in a rotor spinning machine. In accordance with the present 
invention, this objective is attained by connecting each drawing-in roller 
at each spinning station to its own individual drive which is supported by 
the cover of the housing of its respective spinning station. Typically, 
the housing cover at a conventional rotor spinning station is supported in 
hinged fashion at the front of the spinning station. Thus, this manner of 
installation to the cover of the spinning station makes the drawing-in 
roller and its drive directly accessible for maintenance work when the 
spinning station housing is opened. 
Individual drives advantageously economize on couplings and step-up gears. 
Gears and especially couplings are subject to wear, which can result in 
loosened connections and slippage causing inaccurate sliver feeding. This 
has an especially disadvantageous effect when a yarn is being spliced or 
otherwise pieced up, if the quantity of sliver fed in is uneven. 
Specifically, any looseness or slippage in the mechanically meshing 
components of a conventional drive can affect the mechanical coupling 
between a splicing or piecing-up carriage and the drawing-in roller during 
a yarn piecing operation and, in turn, cause inaccurate sliver feeding. 
According to a further feature of the invention, the individual drive of 
each drawing-in roller is a stepping motor. Advantageously, stepping 
motors can be started from any position without slippage. As a general 
rule, the stepping motor is connected to a control unit, which by digital 
signal processing of appropriate sensors present at each spinning station 
is also capable of performing digital control of sliver feeding. This 
makes it possible to perform individualized feeding of each sliver that is 
adapted to the particular situation prevailing at the spinning stations. 
In accordance with a further aspect of the invention, each opening roller 
is similarly connected by its drive shaft to the drive shaft of an 
individual drive, which is also supported by the cover of the housing of 
its respective spinning station. Under this drive concept, the 
conventional rigid drive of all the opening rollers on one side of a 
spinning machine may be replaced by the option of individual drives which, 
in turn, may be adapted to the particular operating situation at a 
spinning station. 
Under a further feature of the invention, the individual drive of each 
opening roller is a driven motor, e.g., an electric motor of the type 
having an outer driven rotor, the opening roller being in the form of a 
ring of card clothing on the outer circumference of the rotor. Electric 
motors of this outer rotor type are capable of installation in the 
component to be driven, making an especially compact design possible which 
is particularly advantageous in the present invention. The individualized 
driving of each drawing-in and opening roller of each spinning station is 
especially advantageous if the spinning rotor is also provided with its 
own individual drive. With a suitable electronic control, each spinning 
station then is largely autonomous so that the spinning stations can be 
assigned different tasks.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the accompanying drawings and initially to FIG. 1, one 
representative spinning station 1 of a multi-station rotor spinning 
machine is shown schematically in section with only those features and 
characteristics contributing to an understanding of the present invention 
being shown and described. 
The functional components of the spinning station 1 are enclosed within a 
housing 2, which is closed at its front by a cover or lid 3 which is 
pivotably supported in a hinge 4 on the underside of the housing 2. The 
main operational components of the spinning station are a spinning rotor 
5, whose shaft 6 is supported rotatably for drive purposes on paired 
support disk bearings, of which only two bearing disks 8a and 8b have been 
shown as representative. The rotor shaft 6 is supported axially via a 
ball-type thrust bearing 9. A drive belt 10 engages the shaft 6 of the 
rotor 5 between the two bearing disks 8a and 8b and extends lengthwise 
along the entire spinning machine to drive all of the rotors of the 
spinning stations at one side of the machine. The arrangement of this type 
of twin-disk bearing for spinning rotors is already known from the prior 
art, such as the aforementioned DE-OS 27 21 386, and therefore need not be 
described in further detail herein. The manner of structural support of 
the rotor and its drive, which have been described earlier, are not 
essential to the invention. The present invention achieves its advantages 
equally well with directly supported rotors and especially when there is 
an individual drive of the rotor. 
The rotor 5 rotates in a chamber 11, which communicates via a conduit 12 
with a source of negative pressure (not shown), as symbolized by the arrow 
13. With the aid of the negative pressure, the fibers for spinning a yarn 
are aspirated into the interior circumferential groove 14 of the rotor. 
In the present exemplary embodiment, the functional elements required for 
drawing-in of a sliver, opening of the sliver into individualized fibers, 
feeding the separated fibers to the rotor for spinning into a yarn, and 
drawing off the spun yarn from the rotor are accommodated in the cover 3 
of the housing 2, as shown schematically in the sectional view of FIG. 1. 
Specifically, a toothed opening roller 15 is rotatably supported with its 
drive shaft 16 in contact with a belt 17 extending longitudinally through 
the length of the machine as the common drive mechanism for the opening 
roller of each spinning station. Located below the opening roller 15 is a 
debris collector 18, which carries the debris 19, such as slubs, dust, 
foreign particles and husk residues, combed out of the sliver away to a 
central collecting point inside the machine by means of negative pressure, 
represented by the arrow 20, through a conduit 21. Located above the 
opening roller 15 is a fiber guide conduit 22, through which the opened 
fibers 23 are directed into the rotor groove 14, where they are spun into 
a yarn 24. The yarn 24 is removed from the housing 2 of the spinning 
station 1 via a yarn draw-off navel 25 through a yarn doff tube 26. 
Drawing off of the yarn 24 is accomplished in the direction of the arrow 
28 via a pair of draw-off rollers 27. Downstream of the pair of draw-off 
rollers, the yarn is delivered to a winding apparatus (not shown) to form 
a cross-wound bobbin. 
Not visible in FIG. 1 is the drawing-in roller, which is disposed adjacent 
the opening roller 15 and therefore is hidden by it in the view of FIG. 1. 
FIG. 2 therefore shows an end view of the spinning station of FIG. 1 to 
illustrate the primary spinning components, with the front panel 29 of the 
cover 3 broken away as indicated by the sectioned edge. A tubular sliver 
condenser 30 is mounted to the cover 3 adjacent the drawing-in roller 32 
for delivering the sliver 31 through the condenser 30 to the drawing-in 
roller 32. The drawing-in roller 32 is driven to rotate in the direction 
of the arrow 33 and a sliver feed table 35 is pivotably mounted adjacent 
the periphery of the drawing-in roller 32 and biased thereagainst by a 
spring device 34. The sliver is compressed between the feed table 35 and 
the drawing-in roller 32 and delivered to the opening roller 15, which is 
driven to rotate in the direction of the arrow 36. The fibers are combed 
out of the sliver and thusly separated from one another. These separated 
fibers 23 are then fed through the fiber guide conduit 22 and into the 
circumferential groove 14 of the rotor 5, where they are spun into a yarn 
24, as already described. The rotor 5 is driven to rotate in the direction 
of the arrow 37. The yarn 24 is drawn off through the yarn doff tube 26, 
as described. 
The preferred drive mechanism for the drawing-in roller 32 is a stepping 
motor 39 located coaxially with the drawing-in roller and connected 
directly to the shaft thereof. Accordingly, as viewed in FIG. 2, the motor 
drive to the drawing-in roller 32 is hidden by the drawing-in roller 32 
itself, but can be seen in the sectional view of FIG. 3 taken through the 
cover 3 along the lines III--III of FIG. 1. 
As will thus be understood, the disposition of the described operational 
components of the spinning station 1 with the cover 3 makes them readily 
accessible when the cover 3 is pivoted open about the hinge 4 in the 
direction of the arrow 38, as can be seen in FIG. 1. 
FIG. 3 shows that the individual stepping drive motor 39 is disposed in 
axial alignment with and behind the drawing-in roller 32. The stepping 
motor 39 is connected to a control unit (not shown) via electrical leads 
40. The drive shaft 41 of the drawing-in roller 32 is connected directly 
to the drive shaft 42 of the stepping drive motor 39, via a rigid coupling 
43, e.g., a flange connection as shown, which serves to make it easier to 
replace one of the two functional elements. Alternatively, the motor could 
be affixed directly on the drive shaft of the drawing-in roller. 
In the alternative embodiment of FIG. 4, an individual drive motor 50 for 
the opening roller 15 is also provided instead of the common drive belt 17 
shown in FIG. 1. In this case, the drive shaft 48 of the opening roller 15 
is connected directly to the drive shaft 49 of the motor 50 via a rigid 
connection 51, for instance a flange connection. The motor 50 is mounted 
to a wall portion 52 affixed to the cover 3 and is connected to a control 
unit (not shown) via an electrical lead 53. 
In the further embodiment of FIG. 5, the individual drive for the opening 
roller 15 is an electrical motor 45 of the type having a stationary 
central drive unit and a driven exterior rotor coaxially about the 
stationary drive unit, rather than an output drive shaft per se. 
An annular covering of card clothing 15a is attached to the driven rotor of 
the motor 45 to serve as the opening roller for the sliver 31. The 
stationary drive unit of the motor 45 is therefore located inside the card 
clothing 15a and is secured to a wall portion 47a of the cover 3 by 
fasteners, such as screws 47. The motor 45 is connected to a control unit 
(not shown) via an electrical lead 46. 
FIG. 6 is a sectional view of the spinning station of FIG. 5 with the cover 
3 broken away along line III--III as in FIG. 3. As will be seen, in 
comparison to the embodiment of FIG. 3, the elimination of the drive shaft 
16 of the opening roller resulting from use of the rotor-type driven motor 
45 provides an advantageously compact design. 
The mounting of the described operational components in the cover 3 is 
accomplished by a modular connection system. That is, each of the 
condenser 30, the drawing-in roller 32, its drive motor 39, the opening 
roller 15 with its drive shaft 16 or with the possible individual drive 
motors 45,50, and the fiber guide conduit 22 are installed in the cover 
via plug-type or screw connections (not shown) in appropriate manners 
enabling them to be detached and removed individually, thereby providing 
easy accessibility and maintenance. 
It will therefore be readily understood by those persons skilled in the art 
that the present invention is susceptible of a broad utility and 
application. Many embodiments and adaptations of the present invention 
other than those herein described, as well as many variations, 
modifications and equivalent arrangements will be apparent from or 
reasonably suggested by the present invention and the foregoing 
description thereof, without departing from the substance or scope of the 
present invention. Accordingly, while the present invention has been 
described herein in detail in relation to its preferred embodiment, it is 
to be understood that this disclosure is only illustrative and exemplary 
of the present invention and is made merely for purposes of providing a 
full and enabling disclosure of the invention. The foregoing disclosure is 
not intended or to be construed to limit the present invention or 
otherwise to exclude any such other embodiments, adaptations, variations, 
modifications and equivalent arrangements, the present invention being 
limited only by the claims appended hereto and the equivalents thereof.