Method and apparatus for time-optimizing occurrence of work at individual operating positions of textile machines

On textile machines, on which packages are wound with a set or reference yarn length, the changing of these packages by means of a travelling package changing device should be carried out in such time optimized manner that the largest possible number of winding positions can be serviced by the package changing device. For this purpose, the yarn length of packages to be wound is signalled continuously to a computer by means of yarn length measuring units and the location of a package changer is continuously signalled to the computer by means of positioning units. If certain packages reach a remainder or residual yarn length before reaching the set yarn length, then the wind-up times for the remainder yarn length of these packages are compared by the computer with the respective travelling times of a package changer to these packages and registered in an optimization procedure, for example for three of these packages. For these three registered packages, the computer determines a package changing sequence in which the waiting times until package change of the individual packages are either equal to zero or at least as small as possible.

BACKGROUND OF THE INVENTION 
The present invention relates to a new and improved method and apparatus 
for time-optimizing the performance or occurrence of work at individual 
operating positions or stations of textile machines. 
It is known that for packages which are used as feed material for the 
so-called warping process, a uniform wound length of yarn is desired, in 
order to avoid as far as possible losses through remnant or residual yarn 
lengths, which are no longer usable, on still not quite empty feed 
packages. 
Uniformly wound yarn lengths can be achieved in an open-end spinning 
method, also referred to in the art as rotor spinning method, by measuring 
the yarn lengths during the winding operation or procedure by means of a 
length measuring unit and by interrupting the spinning process per 
spinning position for a package change operation when a predetermined set 
or reference yarn length is attained. 
The package change procedure can be carried out manually, or by means of 
stationary package changing and yarn piecing devices which are provided 
per spinning position or location, or by means of appropriate devices 
travelling along the spinning positions. 
The aforesaid manual variant is not only labor intensive, but demands from 
the attendant particular skill in yarn piecing, so that the yarn piecings 
are neither too thin nor too thick. At high rotor speeds, for example over 
60,000 rpm, manual yarn piecing is in any event practically impossible. 
On the other hand, package changing and yarn piecing devices which are 
provided for each spinning position constitute, economically overall, an 
expensive solution. 
The economics are improved when there are employed the aforementioned 
travelling devices. Following an interruption at an individual spinning 
position, recorded by a control, such devices are, on each occasion, 
automatically controllably guided to that spinning position for the change 
operation. 
The disadvantage of the last described method step lies, however, in the 
still relatively long waiting times of the individual spinning positions 
until the package change operation has been completed, particularly when 
several packages, which in given circumstances may be spaced apart from 
each other, must be almost simultaneously changed. 
In order to at least partially mitigate this disadvantage, it is suggested 
in German Patent Publication No. 3,030,504 and the corresponding British 
Patent Publication No. 2,065,725, to use a length measuring device in 
combination with a computer unit, in order to send a package changing 
device to that spinning position at which the package has reached at least 
approximately the desired length. The length measuring device determines 
the yarn lengths at a number of spinning positions allocated to it and 
communicates these lengths continuously to the computer unit in which the 
length values are stored and respectively compared with the set or 
reference value. 
When a package reaches a predetermined maximum difference in length from 
the set value, then the computer unit orders the movement of the package 
change device to this package as a precautionary measure, so that when the 
yarn length corresponding to the set value is reached, the package change 
procedure is initiated. The removal of the full package is followed by the 
insertion of an empty bobbin and piecing-up of the yarn end separated from 
the full package. The removal of the full package, the insertion of the 
empty bobbin, and the piecing-up of the yarn end on the empty bobbin are 
also concisely called "doffing", and the device which carries out this 
"doffing" operation is concisely called a "doffer". 
The aforesaid maximum difference in length corresponds to the longest 
necessary travelling time of the doffer including the time for the doffing 
itself. 
The disadvantage of this method lies in the long waiting time until the 
package changing procedure occurs when there prevail only short required 
travelling times. This disadvantage results in a severely limited 
frequency of package changing. 
SUMMARY OF THE INVENTION 
Therefore, with the foregoing in mind it is a primary object of the present 
invention to mitigate this disadvantage. 
Another important object of the present invention is to provide a new and 
improved method and apparatus for the timewise optimization of operations 
or work at individual operating positions or stations of textile machines 
wherein there can be effectively determined the most efficient sequence of 
performing the desired operations or work at the individual operating 
positions. 
Yet a further significant object of the present invention is directed to a 
new and improved construction of apparatus for optimizing as a function of 
time the performance of work at individual operating positions or 
locations of textile machines, which apparatus is relatively simple in 
construction and design, extremely reliable in operation, not readily 
subject to breakdown or malfunction and requires a minimum of maintenance 
and servicing. 
Now in order to implement these and still further objects of the invention, 
which will become more readily apparant as the description proceeds, the 
method for the timewise optimization of an operating procedure at 
individual working positions or locations of textile machines where yarn 
packages with predetermined set yarn lengths are produced, is manifested 
by the features that the instananeous yarn length of each yarn package is 
computed and registered. Upon determination that a predetermined remainder 
or remnant yarn length of a package remains until carrying out a working 
operation a device for carrying out such working operation and movable to 
the working position is controllably guided to such working position with 
a time lead such that the travelling time of the device, even travelling 
through the longest way or path, is shorter than the wind-up time of the 
remainder yarn length. According to important aspects of the invention the 
respective winding times of the remainder yarn lengths of a predetermined 
number of packages with the respective travel times of the device from its 
momentary location to the working positions of the predetermined number of 
packages, while taking into account the time for carrying out the working 
operation at each of these working positions by the device, are so 
optimized by computation with respect to one another that there is 
established a favorable sequence for the working operations such that 
possible loss of production or quality of the yarn per spinning position 
is smallest. 
As alluded to above, the invention is not only concerned with the 
aforementioned method aspects, but also relates to a novel construction of 
apparatus for the performance thereof. According to the invention the 
textile machine is provided with a length measuring unit or device which 
delivers to a computer unit or computer a signal for each package 
corresponding to the length of the already wound yarn. The computer unit 
serves to determine the time lead for guiding the device to the working 
position such that the travelling time of the device, even travelling over 
the longest way or path, is shorter than the wind-up time of the remainder 
yarn length, and which computer unit also serves to control the package 
changing device. According to the invention there are provided additional 
means for emitting a signal indicating the location of the package 
changing device, and the computer unit is structured such that, on the one 
hand, there can be determined two to five packages, the yarn length of 
which has reached the remainder yarn length, and, on the other hand, such 
computer unit also determining the most favorable sequence for performing 
the working operations. 
The advantage achieved by the invention in comparison with the 
above-described state-of-the-art is essentially to be seen in that more 
package changes without interruption of the spinning procedure can take 
place as a percentage of an equal number of spinning positions than is 
possible with the method of the aforementioned German Patent Publication 
No. 3,030,504.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Describing now the drawings, as represented by the dot-dash line, a 
suitable package changer device 10 (FIG. 1) travels along a related 
textile machine (not further illustrated) for producing yarn packages with 
predetermined set yarn lengths, in order to, at a given time (as later 
described), after the said yarn length has been reached, exchange for 
empty bobbins (not shown) the full yarn packages indicated with reference 
numerals 1 to 8 and forming part of the wind-up process of the textile 
machine. 
Each package 1 to 8 has associated therewith a yarn length sensing element 
111 to 118, respectively, (known from the aforesaid German Patent 
Publication No. 3,030,504), which continually measures the length of the 
yarn to be wound-up and supplies to a computer unit or computer 12 a 
signal corresponding to this measured yarn length. Further, the position 
of the changer device 10 is communicated to the computer unit 12 by known 
position elements or position detectors 131 to 138, associated with the 
respective packages, for example constituted by respective end or terminal 
switches. 
The times required for the wind-up phases, for the movement of the changer 
device, the waiting and the package changing are represented 
diagrammatically in FIGS. 2 and 6. There, t is a time required to reach 
the predetermined set yarn length, t.sub.R is a time required to wind-up a 
predetermined remainder yarn length, and t.sub.U is a waiting time of a 
package stopped after achieving the set yarn length until the start of the 
package exchange operation. 
A time required for the travelled distance of the changer device 10 is 
indicated by t.sub.S, the time required for waiting of the changer device 
until the package change is initiated is indicated by t.sub.W, and the 
time required for the package change is indicated by t.sub.D. 
In operation, the yarn lengths sensed by the yarn sensor elements 111 to 
118 are continually communicated to the computer unit or computer 12 
during the production of the individual yarn packages 1 to 8. 
If, by way of example, three packages are taken into consideration from the 
point of view of control for the time optimization of a package change, 
then for all packages which have reached the time region of the remainder 
or remnant yarn length t.sub.R, the computer unit 12 compares the 
remaining wind-up time until the achievement of the set yarn length with 
the respective travelling or travel time of the changer device to these 
packages, and selects for the three packages that combination which 
overall gives for the three selected packages a shortest possible waiting 
time t.sub.U. 
EXAMPLE: FIG. (3) 
As indicated diagrammatically in FIG. 3, the computer 12 has registered for 
the optimization O.sub.1 the remainder yarn lengths t.sub.R.sbsb.4, 
t.sub.R.sbsb.5 and t.sub.R.sbsb.7 of the packages 4, 5 and 7, has 
established in correspondence with the necessary travel distances a change 
sequence A.sup.0 according to which the packages must be exchanged in the 
sequence 4, 7 and 5. 
In order to explain this example, it is mentioned that the travelling time 
of the changer 10 from the package 1 to the package 4 is indicated with 
t.sub.S.sbsb.1-4, from the package 4 to the package 7 with 
t.sub.S.sbsb.4-7, and similarly between the packages 7 and 5 with 
t.sub.S.sbsb.7-5. Furthermore, the other times relating to a specific 
package are provided with an index corresponding with the package number. 
The expired time t.sub.total of the package changer in order to doff the 
said three packages appears mathematically in the ideal case (in which the 
times t.sub.W and t.sub.U =0), as follows: 
______________________________________ 
For package 4: 
t.sub.4.sbsb.total = t.sub.S.sbsb.1-4 + t.sub.D 
t.sub.W.sbsb.4 = 0 
t.sub.U.sbsb.4 = 0 
t.sub.D = t.sub.D.sbsb.4 
for package 7: 
t.sub.7.sbsb.total = t.sub.S.sbsb.4-7 + t.sub.D 
t.sub.W.sbsb.7 = 0 
t.sub.D = t.sub.D.sbsb.7 
t.sub.U.sbsb.7 = 0 
for package 5: 
T.sub.5.sbsb.total = t.sub.S.sbsb.7-5 + t.sub.D 
t.sub.W.sbsb.5 = 0 
t.sub.D = t.sub.D.sbsb.5 
t.sub.U.sbsb.5 = 0 
t.sub.total = t.sub.S.sbsb.1-4 + t.sub.S.sbsb.4-7 + t.sub.S.sbsb.7-5 + 
3t.sub.D 
______________________________________ 
In the normal case (FIG. 4), t.sub.W.sbsb.4, t.sub.W.sbsb.7 and 
t.sub.U.sbsb.5 are not zero, but the time t.sub.U.sbsb.5 is as short as 
possible. The times t'.sub.R.sbsb.4, t'.sub.R.sbsb.7 and t'.sub.R.sbsb.5 
differ correspondingly from the times t.sub.R.sbsb.4, t.sub.R.sbsb.7 and 
t.sub.R.sbsb.5 (all in FIG. 3) and are registered or detected by the 
optimization O.sub.2. 
However, if the computer determines after completion of a package change 
that in the meantime another change sequence must be given priority, for 
example in order, after the change of package 7, to change not the package 
5 but the still more distant package 8, then the computer 12 changes the 
sequence. In so doing, the computer has determined by a further 
optimization O.sub.3 (FIG. 5) that the remainder yarn length 
t.sub.R.sbsb.8 reaches its end so soon after the remainder yarn length 
t'.sub.R.sbsb.5 reaches its end so soon after the remainder yarn that a 
new sequence A.sup.I, in which the package 8 is changed after the package 
7 and before the package 5, gives overall the shortest waiting time 
t.sub.U, namely the time t'.sub.U.sbsb.5. The times for these change 
sequences are represented in FIG. 5 with full lines. 
In the same figure there is shown with dotted lines the time progression of 
a change sequence A.sup.II, from which it can be seen that in such a 
sequence the sum of the times t".sub.U.sbsb.5 and t.sub.U.sbsb.8 is 
greater than the time t'.sub.U.sbsb.5 of the sequence A.sup.I. 
As a variant, the aforesaid optimization procedure can also be used for a 
rotor spinning machine on which the packages 1 to 8 are produced 
additionally with a predetermined excess length exceeding the set yarn 
length. 
The time required for this excess length is indicated by t.sub.Ue (FIG. 6). 
The waiting time t.sub.U, which follows immediately this time t.sub.Ue 
required for the excess length, is the intervening time after stopping of 
the package, that is after expiration of the time t.sub.Ue, until exchange 
of the package and re-piecing of the thread, whether manually or 
mechanically. 
In operation of this variant, for all packages which have reached the time 
region of the remainder yarn length t.sub.R, a computer 121 (FIG. 1) 
compares the remainder wind-up time up to and including the time t.sub.Ue 
for the achievement of the maximum excess length with the respective 
travelling times of the changer device to these packages, and selects for 
three packages that combination which overall gives for the three selected 
packages a shortest possible time t.sub.Ue. An example of such a variant 
is shown in FIG. 7, in which a package changer 101, starting from the 
position shown in FIG. 1, changes one after another the packages 4, 7 and 
5 corresponding to the change sequence A.sup.III. 
For this, the optimization O.sub.4 has procedurally established the 
remainder yarn length t".sub.R.sbsb.4, t".sub.R.sbsb.7 and t".sub.R.sbsb.5 
in such a manner that the packages 4 and 7 are produced without excess 
lengths and the package 5 is produced with an excess length. 
In the example illustrated in FIG. 8, a new change priority is selected by 
the computer 121 after the change of the package 4, in order, in 
accordance with an exchange sequence A.sup.IV, after the change of the 
package 7, to exchange first the package 8 and thereafter the package 5. 
This exchange sequence is determined procedurally by the optimization 
O.sub.5. 
From FIG. 8 it can be seen that the packages 7 and 8 are exchanged without 
excess lengths, whereas the package 5, after reaching the excess length, 
is stopped by a length measuring unit forming part of the register or 
storage until the exchange of the package, that is during a waiting time 
t.sub.U. The time t.sub.U is limited by a subsequent manual or mechanical 
change of the package of the corresponding spinning position. 
With manual exchange of the packages, the computer 121 additionally 
initiates an indication after expiration of the time t.sub.U.sbsb.e for 
this corresponding winding position, and excludes this winding position 
temporarily from the optimization program. Re-inclusion in the 
optimization program occurs, for example, through a manual signal emission 
(not shown) by the attendant after change of the package and piecing of 
the thread at the corresponding spinning position. The expression "piecing 
of the thread" covers both piecing to a new package with uninterrupted 
spinning process at this spinning position, or new start-spinning after an 
interrupted spinning process. 
A further variant of the use of the optimization procedure consists in 
optimizing the times of cleaning of the rotors of the individual spinning 
positions after the stopping of the spinning positions by means of a yarn 
length measuring unit forming part of a computer 122. 
The optimization procedure then operates in accordance with the variant 
illustrated and described with reference to FIGS. 2, 4 and 5. 
The registered times t.sub.R of the remainder yarn lengths correspond to 
the remainder yarn length before the time of the cleaning, and the waiting 
times t.sub.U are waiting times after stopping of the spinning process per 
spinning position until the time of the cleaning. After completion of the 
optimization process for the cleaning of the rotors, there comes into 
operation the already described optimization procedure for the package 
exchange or possibly, simultaneously with the package exchange, also for 
the repeated cleaning of the rotors during exchange and for the new 
start-spinning. 
A second variant of the use of the optimization procedure for the cleaning 
of the rotors of the individual spinning positions consists in that the 
cleaning occurs within a time period following immediately a predetermined 
set time for the cleaning, for example after the half-set yarn length is 
reached. For this, the optimization procedure selects, for example, three 
spinning positions whose wind-up times lie within a time t.sub.R of a 
remainder yarn length before achieving the aforesaid set time. 
This optimization procedure operates substantially in accordance with the 
variant illustrated and described with reference to FIGS. 6 and 7. There, 
the end of the time t.sub.R corresponds to the set time for the cleaning 
of the rotor, and the time t.sub.Ue shown in FIG. 7 corresponds to the 
time range within which the rotor cleaning must occur. After expiration of 
the time t.sub.Ue the spinning position is stopped for the time t.sub.U. 
The rotor is cleaned before spinning is re-started. 
As already mentioned for the first cleaning variant, after completion of 
this optimization procedure there comes into operation the optimization 
procedure for the package changing operation or possibly, simultaneously 
with the package changing, also for the repeated cleaning of the rotor 
during changing and for the new start-spinning. 
The intervals shown in FIGS. 2 to 8 corresponding to the different times 
are not according to scale. By way of example, the changer 10; 101 has a 
speed of travel which permits it to travel past 200 spinning positions in 
2.5 minutes and requires for the package changing, cleaning and new 
start-spinning a time of 20 to 30 seconds. 
The claimed method is, on the other hand, not limited only to use for the 
changing of packages on rotor spinning machines. It is basically usable 
for all textile machines in which yarn packages are to be produced with 
predetermined set yarn lengths and in which the packages, after reaching 
this set yarn length, are changed by a device guided to the working or 
operating position. 
The invention therefore also relates to a textile machine with a plurality 
of working positions, a travelling service apparatus, a travel path for 
the apparatus and a control device. The machine is provided with a data 
transmission system to transmit operating condition data from the working 
positions to the control device, location or position data from the 
service apparatus to the control device, and control data from the control 
device to the service apparatus. The operating condition data represent 
the operating conditions of the individual working positions, and the 
location data represent the location of the service or servicing apparatus 
relative to the working position. The control data control the movements 
of the service apparatus along the travel path. The control device is so 
arranged that the control data are produced corresponding to the received 
operating condition and location or positional data. 
The invention further relates to a control method for a textile machine 
with a plurality of working positions, a travelling service apparatus, a 
travel path for the apparatus and a control device. The operating 
conditions of the various working positions and the location of the 
service apparatus relative to the working positions can be determined and 
transmitted as data to the control device. The movements of the service 
apparatus along the travel path can be controlled by the control device in 
dependence upon the determined operating conditions and location. 
The textile machine could be, for example, an open-end spinning machine, a 
ring spinning machine or a winding machine. The determined operating 
conditions could be running times and/or normal operation/fault and/or 
"full package" (wound yarn lengths). The control device can be so arranged 
that the movements of the service apparatus are optimized according to a 
program. The optimizing criteria of the program can represent or at least 
take into account the minimum total time for the operating procedures of 
the service apparatus, pre-programmed service operation on a plurality of 
working positions being included under the expression "operating 
procedures". 
While there are shown and described present preferred embodiments of the 
invention, it is to be distinctly understood that the invention is not 
limited thereto, but may be otherwise variously embodied and practiced 
within the scope of the following claims. Accordingly,