Abstract:
A creel ( 18 ) for a textile machine ( 1 ) producing cheeses ( 11 ), with a drive device ( 27 ) integrated into the creel ( 18 ) having an electromotor ( 35 ) which can be loaded with a braking current for braking the cheese ( 11 ) by initiating a braking moment directed counter to the rated current of the electromotor. A coolant circuit ( 36 ) is arranged inside the creel ( 18 ) for removal of the motor heat of the electromotor ( 35 ) of the drive device ( 27 ).

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of German patent application DEP10040108.2filed Aug.17, 2000, herein incorporated by reference. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to a creel for a textile cheese-producing machine and, more particularly, to such a creel which comprises an integrated electromotor drive device which can be loaded or charged with a braking current counter to the nominal rated current of the electromotor for braking the cheese.  
         BACKGROUND OF THE INVENTION  
         [0003]    Such creels are known, e.g., in conjunction with bobbin winding devices that were developed for the production of cheeses of the “precision winding” and “stepped precision winding” types.  
           [0004]    Subsequently published German Patent Publication DE 199 08 093.3, for example, describes a bobbin winding device in which a cheese held in a creel is directly driven by a drive motor integrated into the creel. The cheese rests on a pressure roller that is not driven itself. Traversing of the yarn to be wound takes place by means of a finger-like yarn guide operated by a separate drive. The two drives can be controlled via an appropriate control device such that a defined, pre-selectable winding ratio is always obtained.  
           [0005]    Since it is necessary to stop a cheese frequently in the course of the overall process of winding yarn onto the cheese, for example, when a yarn supply cop is exhausted, upon a yarn break, or following a controlled cutting of the yarn via a yarn cleaner, the known winding device also comprises a pneumatically loadable braking device integrated into the creel. This known braking device is comprised of a brake lining fixed on the stator housing of the electromotor to rotate in unison with the housing, against which brake lining a contact surface of a tube receiving plate, embodied as a brake disk, can be pneumatically pressed. The braking force thereby produced rapidly brings the cheese to a stop.  
           [0006]    However, this known cheese winding device has a number of disadvantages. Both the rotating brake disk and the stationary brake lining are subject to significant wear and therefore the braking device requires intensive maintenance. In addition, the brake dust created can readily enter into the axial sliding guide of the cheese drive as well as into the bearing of the electromotor and considerably hampers or may even cause breakdown of these components.  
           [0007]    Other cheese winding devices are known, for example from German Patent Publication DE 198 36 701 A1, in which a grooved drum that drives the cheese and at the same time traverses the yarn is electrically braked to a standstill after the cheese has been lifted off. To this end, the drive motor of the grooved drum is loaded or charged with a braking current that is usually a multiple of the rated current of the drive motor. In the process, the drive motors of such cheese winding devices are subjected to considerable loads, especially when large cheeses must be repeatedly braked and accelerated at short time intervals. Thus, such drives are exposed to significant stresses, especially thermal loads.  
           [0008]    It is known from German Patent Publications DE 21 06 898 A1 or German Patent DD 214,114 that textile machine drive devices which are subjected to large thermal loads can be provided with cooling ribs so that the motor heat can be removed via convection and radiation into the ambient environment. Alternatively, as described in German Patent DE 27 14 299 C2, such drive devices can be cooled by a permanent application of compressed air.  
           [0009]    These known drive devices are comparatively large, bulky and heavy, especially when correspondingly large output data are demanded. However, drive devices which are intended to be integrated directly into the creel of a cheese-producing textile machine must be as small and lightweight as possible, since during the winding process their weight results in an additional unwanted load on the rotation of the cheese on the associated pressure roller, especially when such a drive device is arranged far to the front on the creel. Thus, these known drive devices are only very poorly suited for being integrated in the creel of a textile cheese-producing machine. Therefore, such drive devices arranged in the area of the tube receiving plates of a creel should be as lightweight as possible but nevertheless strong in performance. However, the achievable power strength of an electromotor, e.g., of an electronically commuted direct-current motor is considerably dependent on the magnitude of its removable heat flow.  
         SUMMARY OP THE INVENTION  
         [0010]    In view of the previously described state of the art, the present invention therefore seeks to address the problem of overcoming the disadvantages of the devices known in the state of the art and, more particularly, the present invention seeks to develop a creel that makes it possible to use relatively small and therewith lighter weight drive devices with great power density while assuring a sufficiently great strength of the drive devices.  
           [0011]    The present invention addresses this problem by providing a creel of the type basically comprising an electromotor drive device integrated into the creel, wherein the creel may be braked when necessary by loading the electromotor with a braking current which initiates a braking moment directed counter to a rated current of the electromotor. In accordance with the present invention, a coolant circuit is arranged inside the creel for removal of motor heat from the electromotor.  
           [0012]    The design of the creel in accordance with the invention has the particular advantage that the motor heat produced by the electromotor is immediately distributed onto a relatively large cooling surface. This assures that a thermal overloading of relatively small drive devices is prevented, even when they are fully loaded, and safety cutoffs due to overheated drives, that result in losses of efficiency of the textile machines, are avoided.  
           [0013]    In a preferred embodiment, the coolant circuit comprises a heat receiving extent in the area of the electromotor and a cooling extent that is distinctly longer in comparison to the heat receiving extent. The cooling extent is formed to extend either within one of two creel arms or within the complete creel. In both instances, the creel wall located in the area of the cooling extent acts as a heat exchanger so that a large part of the motor heat produced can be removed over a large surface area and thereby dissipated into the environment.  
           [0014]    The coolant circuit is preferably embodied as a closed system, i.e., the coolant circulates within the system without direct contact with the environment. Either a liquid, preferably water, or a gas, preferably air, may be used as coolant.  
           [0015]    In an advantageous embodiment, the circulation of the coolant takes place via free convection wherein the change of density of the coolant occurring due to the heating of the coolant in the area of the heat receiving extent causes the coolant to flow inside the cooling circuit and thereby transports the introduced motor heat from the heat receiving extent to the cooling extent where the heat is removed via the creel wall into the environment.  
           [0016]    In an alternative embodiment, the transport of heat within the coolant circuit may be supported by forced convection. In this instance, depending upon the type of the coolant used, either a ventilator or a liquid pump is arranged inside the coolant circuit. The use of such an additional, external power source can increase the circulation of the coolant inside the coolant circuit and therewith improve the cooling performance of the device.  
           [0017]    It is also possible to design the coolant circuit as a partially-closed circuit, wherein compressed air is constantly or temporarily blown via an injector nozzle into the coolant circuit and the circulation of the coolant supported therewith. Excess compressed air is removed thereby through an appropriate air evacuation bore. 
       
    
    
       [0018]    Further details, features and advantages of the present invention will be described in and understood from an exemplary embodiment described hereinbelow with reference to the accompanying drawings.  
       BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    [0019]FIG. 1 is a partially schematic side elevational view of a work station of a textile cheese-producing machine incorporating the coolant circuit of the present invention.  
         [0020]    [0020]FIG. 2 is a top view, partially in cross-section, of a creel according to a first embodiment of the present invention providing an integrated coolant circuit.  
         [0021]    [0021]FIG. 3 is a cross-sectional view of the creel of FIG. 2 taken along line III-III thereof.  
         [0022]    [0022]FIG. 4 is another cross-sectioned top view, similar to FIG. 2, of a creel according to a second embodiment of the present invention providing a ventilator arranged inside the coolant circuit.  
         [0023]    [0023]FIG. 5 is a cross-sectional view of the creel of FIG. 4 taken along line V-V thereof..  
         [0024]    [0024]FIG. 6 is another cross-sectioned top view, similar to FIGS. 2 and 4, of a creel according to a third embodiment of the present invention providing a liquid pump arranged inside the coolant circuit.  
         [0025]    [0025]FIG. 7 is another cross-sectioned top view, similar to FIGS. 2, 4 and  6 , of a creel according to a fourth embodiment of the present invention providing a half-closed coolant circuit. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]    Referring now to the accompanying drawings and initially to FIG. 1, a textile cheese-producing machine, preferably an automatic cheese winder in this exemplary embodiment, is schematically shown in a side elevational view and is designated in its entirety by reference numeral  1 .  
         [0027]    Such automatic cheese winders customarily comprise a plurality of similar work stations, in the present instance cheese winding stations  2 , commonly referred to as winding heads, aligned with one another between the end frames (not shown) of the machine.  
         [0028]    Textile yarn from spinning cops  9  manufactured on a ring spinning machine are rewound by these winding heads  2  onto large-volume cheeses  11  in a manner that is already known and therefore need not be explained in more detail. After the production of each cheese  11  has been completed, the cheese  11  is transferred onto cheese transport device  21  running the length of the machine, e.g., by pivoting creel  18  about pivot axis  19 , and the cheese  11  is thereby transported to a bobbin loading station or the like (not shown) arranged at an end of the winding machine.  
         [0029]    Additionally, such automatic cheese winders  1  customarily comprise a logistic device in the form of a bobbin and tube transport system  3 . Spinning cops  9  and empty cop tubes  34  are supported on transport plates  8  in upstanding disposition and these transport plates  8  are circulated within the machine via various conveyor runs of this logistic device. FIG. 1 shows only the following parts of a known bobbin and tube transport system  3 : Cop feed conveyor  4 , storage conveyor  5 , which can be driven in a reversing manner, one of transversal transport conveyor  6  running to winding heads  2  as well as tube return conveyor  7 . The spinning cops  9  thusly transported are rewound to large-volume cheeses  11  at the unwinding position  10  located along each transversal transport conveyor  6  at the associated winding head  2 .  
         [0030]    In addition, such an automatic cheese winder comprises a central control unit  37  connected via machine bus  40  to the separate winding-head computers  39  of the individual winding heads  2 .  
         [0031]    As is known and therefore only schematically indicated, each individual winding head  2  comprises various devices that make possible an orderly operation of these work stations. As depicted in FIG. 1, a yarn  30  being rewound at the winding head  2  travels from spinning cop  9  to cheese  11  along a path adjacent which various operational devices are provided to perform various operations as a part of the winding process, e.g., a yarn suction nozzle  12 , a yarn grasping tube  42 , a splicing device  13 , a yarn tensioning device  14 , a yarn cleaner  15 , a paraffin application system  16 , a yarn cutting device  17 , a yarn tension sensor  20  and an underyarn sensor  22 .  
         [0032]    Each winding head  2  includes a cheese winding device, designated in its entirety by reference numeral  24 , which comprises creel  18  supported in such a manner that it can move about pivot axis  19 . Creel  18  can also be pivoted about axis  25 , e.g., to manufacture conical cheeses.  
         [0033]    During the winding process, the driven cheese  11  rests with its surface on pressure roller  26  and frictionally entrains this pressure roller  26 , that has no drive. The cheese  11  is driven via drive device  27  with speed control. This drive device  27  is embodied, e.g., as electronically commutable direct-current motor  35  and is arranged in bearing housing  23  in such a manner that it can be shifted, as indicated in FIGS.  2  to  7 . This bearing housing  23  is formed on one of creel arms  33 A or  33 B.  
         [0034]    Yarn traversing device  28  is provided to traverse yarn  30  during the winding process. Such a traversing device is only indicated schematically in FIG. 1 and is described in detail in German Patent Publication DE 198 58 548 A1. Yarn traversing device  28  is basically comprised of yarn guide  29  in the form of a finger which is loaded by electromechanical drive  31  to traverse yarn  30  between the two front sides of cheese  11 . Yarn  30  glides during its displacement by yarn guide  29  on guide edge  32 .  
         [0035]    [0035]FIG. 2 shows a top view of a first embodiment of creel  18  of the present invention. As shown, a closed coolant circuit  36  is integrated in creel arm  33 A, which circuit is comprised of heat receiving extent  38  and of cooling extent  41 , which is, as a rule, distinctly longer. Heat receiving extent  38  is arranged in the area of drive device  27  and surrounds electromotor  35  almost completely. Heat receiving extent  38  is followed, as shown, by cooling extent  41  that comprises two conduits  44 ,  45  separated by intermediate wall  43 . A coolant circulates inside coolant circuit  36  by the process of free convection in the exemplary embodiment according to FIGS. 2 and 3. The direction of flow of this coolant, either a liquid, e.g., water, or a gas, e.g., air, is indicated by arrows  46 . The coolant dissipates the motor heat, taken up in the area of heat receiving extent  38 , into the ambient environment as the coolant moves through the area of cooling extent  41  via the walls of creel arm  33 A which provide a sufficiently large surface area for dissipating the heat and, thus, the coolant assures that the motor temperature of direct-current motor  35 , that is preferably electronically commuted, does not exceed a limit value.  
         [0036]    The exemplary embodiments of FIGS. 4, 5 and  6  differ from the previously described embodiment of FIGS. 2 and 3 essentially in that almost the entire creel  18  functions as a heat exchanger rather than only one creel arm serving as the cooling surface. Thus, coolant circuit  36  is arranged in both creel arms  33 A,  33 B as well as in the creel base connecting the creel arms. Moreover, in the exemplary embodiment of FIGS. 4, 5 and  6 , the flow  46  of the coolant is supported by a forced convection.  
         [0037]    Specifically, a flow producer  47 ,  49  is connected into coolant circuit  36 , preferably in the area of creel arm  33 B, which producer constantly accelerates the coolant. The flow producer is either embodied as a ventilator  47  (FIG. 4) if a gas is used as coolant, which ventilator is loaded by drive  48 , or as a liquid pump  49  (FIG. 6) if a liquid is used as coolant, which pump is also loaded by corresponding drive  50 .  
         [0038]    [0038]FIG. 7 shows a creel  18  with a partially closed coolant circuit  36  wherein compressed air  52  is permanently or temporarily blown into cooling circuit  36  via injector nozzle  51  arranged, e.g., in the area of creel arm  33 A, which results in an elevated circulation of the coolant, in this case air. Excess compressed air is removed via air evacuation bore  53  arranged, e.g., in the area of creel arm  33 B.  
         [0039]    It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of 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.