Apparatus and method for start-spinning on an open-end spinning machine

Abstract

An apparatus for start-spinning a thread is arranged movably relative to each individual spinning unit along an open-end spinning machine in order to be able to perform start-spinning operations there if required. In order to avoid having to start spinning at the generally very high operating speeds of the spinning rotors, because the start-spinning operation would be made more difficult by these high speeds, in accordance with the invention the spinning rotor runs up to speed from a standstill during the start-spinning operation after a brake has been released, so that spinning is started during a period in which the spinning rotor has not yet achieved its operating speed. The start-spinning speed is therefore clearly lower than the operating speed of the spinning rotor.

Having thus fully disclosed our invention, what we claim is: 
     
       1. An apparatus for start-spinning, movable along an open-end spinning machine to a spinning unit, which returns a thread to a spinning rotor of said spinning unit and removes said thread therefrom again after spinning has been started, containing means for controlling the moment the start-spinning operation is commenced in such a manner that said start-spinning operation is performed during the period in which .[.the.]. .Iadd.a .Iaddend.previously braked spinning rotor of said spinning unit starts up and at a speed which is lower than the operating speed of said spinning rotor.Iadd., said spinning machine including a plurality of said spinning units with common driving means, said spinning unit including rotor brake means actuable independently of neighboring commonly driven spinning units, said apparatus including brake control means for controlling actuation and release of the rotor brake means, said means for controlling including means for automatically initiating the start spinning operation in response to release of the rotor brake means to assure piecing during acceleration of the rotor toward its operating speed.Iaddend.. 
     
     
       2. The apparatus according to claim 1, in which the moment of start-spinning is stipulated by briefly coupling the apparatus for start-spinning with .[.a.]. .Iadd.the rotor .Iaddend.brake .Iadd.means .Iaddend.of said spinning rotor. 
     
     
       3. The apparatus according to claim 2, in which a motion of the .Iadd.rotor .Iaddend.brake .Iadd.means .Iaddend.occurring during release of said spinning rotor brake .Iadd.means .Iaddend.is transferred as a starting signal to the apparatus for start-spinning, which contains means for delaying the start-spinning operation. 
     
     
       4. The apparatus according to claim 3, in which said means for delaying the start-spinning operation are adjustable. 
     
     
       5. The apparatus according to claim 1, in which draw-off rollers are provided which briefly handle the thread transport after spinning is started. 
     
     
       6. The apparatus according to claim 5, in which means for determining the tension of the thread are provided between the spinning rotor and the draw-off rollers, said means serving as a control element for switching on the drive means of said draw-off rollers. 
     
     
       7. The apparatus according to claim 5, in which means for producing a thread reserve are provided between the draw-off rollers and the spinning rotor, said means providing the length of thread required for insertion in the spinning rotor to start spinning. 
     
     
       8. The apparatus according to claim 6, in which the speed of rotation of the draw-off rollers is lower than the speed of rotation given by a winding roller to a bobbin for the thread to be wound. 
     
     
       9. The apparatus according to claim 5, in which means for determining the tension of the thread are arranged behind--viewed in the direction the thread is drawn off--the draw-off rollers, said means being able to be set for a preselected value and being attached to means for eliminating a clamping pressure between said draw-off rollers. 
     
     
       10. The apparatus according to claim 1, containing draw-off rollers which include drive means which can be driven in both directions for returning the thread to the spinning rotor and subsequently drawing said thread off again. 
     
     
       11. The apparatus according to claim 10, in which means for determining the tension of the thread are provided between the spinning rotor and the draw-off rollers, said means serving as a control element for reversing the drive of the draw-off rollers from supply to the spinning rotor to drawing off again. 
     
     
       12. The apparatus according to claim 10, in which the speed of rotation of the draw-off rollers in the draw-off direction away from the spinning rotor is lower than the speed of rotation applied by a winding roller to a bobbin for the thread to be wound. 
     
     
       13. The apparatus according to claim 10, in which means for determining the tension of the thread are arranged behind--viewed in the direction the thread is drawn off--the draw-off rollers, said means being able to be set for a preselected value and being attached to means for eliminating a clamping pressure between said draw-off rollers. 
     
     
       14. The apparatus according to claim 1, having means for actuating a thread stop-motion, arranged on the spinning unit, controlling the supply of fibres to the spinning unit. 
     
     
       15. The apparatus according to claim 1, containing a lift-off winding roller, equipped with lifting means for lifting a bobbin away from a winding roller and having drive means which can be switched on in both directions. .Iadd. 
     
     
       16.  A method for start-spinning a thread on an open-end spinning machine comprising: returning a thread to a spinning rotor of an open-end spinning unit,   removing said thread from said spinning rotor after spinning has been started,   and controlling the moment the start-spinning operation is commenced in such a manner that said start-spinning operation is performed during the period in which a previously braked spinning rotor of said spinning unit starts up and at a speed which is lower than the operating speed of said spinning rotor, said spinning machine including a plurality of said spinning units with common driving means, said spinning unit including rotor brake means actuable independently of neighboring commonly driven spinning units with common drives, said controlling including automatically initiating the start-spinning operation in response to release of the rotor brake means to assure piecing during acceleration of the rotor towards its operating speed. .Iaddend. .Iadd.   
     
     
       17.  The method according to claim 16, wherein said controlling includes briefly coupling apparatus for start-spinning with the rotor brake means of said spinning rotor. .Iaddend. .Iadd.18. The method according to claim 17, wherein said controlling includes transferring motion of the rotor brake means occurring during release of said rotor brake as a starting signal to said apparatus for start-spinning, said apparatus for start-spinning containing means for delaying the start-spinning operation. .Iaddend. .Iadd.19. The method according to claim 18, wherein said means for delaying the start-spinning operation are adjustable..Iaddend. 
     
     
        .Iadd.  .  The method according to claim 16, further comprising briefly handling the thread transport by draw-off rollers after spinning is started. .Iaddend. .Iadd.21. The method according to claim 20, further comprising determining the thread tension between the spinning rotor and the draw-off rollers by tension determining means, said tension determining means serving as a control element for switching on drive means of said draw-off rollers. .Iaddend. .Iadd.22. The method according to claim 20, further comprising producing a thread reserver between the draw-off rollers and the spinning rotor by way of thread reserve producing means, said producing of a thread reserve including providing a length of thread required for insertion in the spinning rotor to start spinning. .Iaddend. .Iadd.23. The method according to claim 21, in which the speed of rotation of the draw-off rollers is lower than the speed of rotation given by a winding roller to a bobbin for the thread to be wound. .Iaddend. .Iadd.24. The method according to claim 20, in which means for determining the tension of the thread are arranged behind--viewed in the direction the thread is drawn off--the draw-off rollers, said means being able to be set for a preselected value and being attached to means for eliminating a clamping pressure between said draw-off rollers. .Iaddend. 
     
     
        .Iadd.25.  The method according to claim 16, wherein said returning and removing of a thread includes driving draw-off rollers which include drive means which can be driven in both directions for returning the thread to the spinning rotor and subsequently drawing said thread off again. .Iaddend. .Iadd.26. The method according to claim 25, further comprising determining the thread tension between the spinning rotor and the draw-off rollers by tension determining means, said tension determining means serving as a control element for reversing the drive of the draw-off rollers from supply to the spinning rotor to drawing off again. .Iaddend..Iadd. 27. The method according to claim 25, in which the speed of rotation of the draw-off rollers in the draw-off direction away from the spinning rotor is lower than the speed of rotation applied by a winding roller to a bobbin for the thread to be wound. .Iaddend..Iadd. 28. The method according to claim 25, in which means for determining the tension of the thread are arranged behind--viewed in the direction the thread is drawn-off--the draw-off rollers, said means being able to be set for a preselected value and being attached to means for eliminating a clamping pressure between said draw-off rollers. .Iaddend. .Iadd. 29. The method according to claim 16, further comprising actuation of a thread stop motion, arranged on the spinning unit, for controlling the supply of fibers to the spinning unit. .Iaddend..Iadd. 30. The method according to claim 16, wherein a lift-off winding roller is provided, further comprising using said lift-off winding roller for lifting a bobbin away from a winding roller, said lift-off winding roller having drive means which can be switched on in both directions. .Iaddend..Iadd. 31. The method according to claim 16, further comprising selectively moving a mobile unit containing means for said returning, removing, and controlling along an open-end spinning machine to respective servicing stations adjacent respective spinning units of said spinning machine. .Iaddend. .Iadd. 32. An apparatus for start-spinning, movable along an open-end spinning machine to a spinning unit, which returns a thread to a spinning rotor of said spinning unit and removes said thread therefrom again after spinning has been started, containing means for controlling the moment the start-spinning operation is commenced in such a manner that said start-spinning operation is performed during the period in which a previously braked spinning rotor of said spinning unit starts up and at a speed which is lower than the operating speed of said spinning rotor, in which draw-off rollers are provided which briefly handle the thread transport after spinning is started, and   in which means for determining the tension of the thread are arranged behind--viewed in the direction the thread is drawn off--the draw-off rollers, said means being able to be set for a preselected value and being attached to means for eliminating a clamping pressure between said draw-off rollers. .Iaddend. .Iadd. 33. An apparatus for start-spinning, movable along an open-end spinning machine to a spinning unit, which returns a thread to a spinning rotor of said spinning unit and removes said thread therefrom again after spinning has been started, containing means for controlling the moment the start-spinning operation is commenced in such a manner that said start-spinning operation is performed during the period in which a previously braked spinning rotor of said spinning unit starts up and at a speed which is lower than the operating speed of said spinning rotor,   containing draw-off rollers which include drive means which can be driven in both directions for returning the thread to the spinning rotor and subsequently drawing said thread off again, and   in which means for determining the tension of the thread are arranged behind--viewed in the direction the thread is drawn off--the draw-off rollers, said means being able to be set for a preselected value and being attached to means for eliminating a clamping pressure between said draw-off rollers.