Method and apparatus for detecting a thread supply boundary on a yarn storage drum

A thread storage and feed device for thread-processing machines comprising a housing, a drum-shaped storage body supported on said housing and defining a storage surface for a thread supply which is defined by thread windings on said storage surface, said storage surface having at least distinct first and second circumferential sections, said storage and feed device further comprising at least one signal-generating sensor supported by said housing, said sensor being directed toward a predetermined scanning zone of the storage surface for determining a movement of a boundary of the thread supply, comprising the improvement wherein said scanning zone extends in a circumferential direction and includes said first and second circumferential sections which are disposed circumferentially relative to one another, the first and second circumferential sections of the storage surface differing from one another with respect to their scanning properties, and at least two said sensors being provided on said housing and being positioned in such a way that the scanning property of said first circumferential section or of the thread supply when said thread resupply is disposed on said first circumferential section is scanned by a first one of said sensors and that, simultaneously, the scanning property of said second circumferential section or of the thread supply when said thread supply is disposed on said second circumferential section is scanned by a second one of said sensors, said first and second circumferential sections being circumferentially spaced apart, and a distance between the first and second sensors corresponding to a circumferential spacing between the first and second circumferential sections of the storage surface or to an integral multiple thereof, said storage body being connected to rotary drive means for rotating said storage body, said rotary drive means including means for stopping the storage body exclusively at a rotary position at which the first and second sensors are simultaneously directed at the first and second circumferential sections of the storage surface.

A thread storage and feed device for thread-processing machines comprising a housing, a drum-shaped storage body supported on said housing and defining a storage surface for a thread supply which is defined by thread windings on said storage surface, said storage surface having at least distinct first and second circumferential sections, said storage and feed device further comprising at least one signal-generating sensor supported by said housing, said sensor being directed toward a predetermined scanning zone of the storage surface for determining a movement of a boundary of the thread supply, comprising the improvement wherein said scanning zone extends in a circumferential direction of said storage drum and includes a plurality of said first and second circumferential sections arranged in said circumferential direction in an alternating arrangement, at least first, second and third sensors being provided such that said first to third sensors are circumferentially spaced from one another in such a way that one of said first to third sensors is directed at one of said first circumferential sections and another of said first to third sensors is simultaneously directed at one of said second circumferential sections of the storage surface, the first and second circumferential sections of the storage surface differing from one another with respect to their scanning properties, the scanning property of said first circumferential section or of the thread supply when said thread supply is disposed on said first circumferential section being scanned by said one of said first to third sensors and that, simultaneously, the scanning property of said second circumferential section or of the thread supply when said thread supply is disposed on said second circumferential section being scanned by said another of said first to third sensors.

A method of determining the movement of a thread supply boundary of a thread supply on a storage surface, said storage surface defined by a drum-shaped storage body of a thread storage and feed device for a thread-processing machine, said storage and feed device including scanning means which scans a scanning zone on said storage surface to control supplying of the thread to said thread supply depending upon the presence or absence of said thread supply in said scanning zone, said method comprising the steps of:

• providing first and second circumferential sections of said storage surface which are disposed in said scanning zone and are circumferentially offset one with respect to the other, said first and second circumferential sections having different scanning properties;
• scanning said first and second circumferential sections to 1) produce at least two non-identical storage surface signals which respectively correspond to said different scanning properties of said first and second circumferential sections in the absence of said thread supply boundary, and 2) produce at least two substantially identical thread signals corresponding to a scanning property of said thread supply covering said first and second circumferential sections in the presence of said thread supply boundary;
• controlling supplying of said thread to said thread supply in response to said non-identical storage surface signals and said substantially identical thread signals being produced by said scanning step;
• and
• whereby said scanning property of at least one of said circumferential sections differs from said scanning property of said thread.

A thread storage and feed device for a thread-processing machine, comprising:

• a housing;
• a storage drum supported on said housing and defining a circumferential storage surface which stores a thread supply thereon defined by a plurality of thread windings, said storage surface including a scanning zone which extends in a circumferential direction and comprises at least first and second circumferential sections of said storage surface, said first circumferential section being circumferentially offset relative to said second circumferential section, and said first and second circumferential sections having respective first and second scanning properties which are different one from the other;
• sensor means for scanning said first and second circumferential sections, said sensor means being supported by said housing and directed toward said scanning zone of said storage surface to detect the presence of a thread supply boundary of said thread supply in said first and second circumferential sections, said sensor means generating non-identical first and second storage surface signals which respectively correspond to said respective first and second scanning properties of said first and second circumferential sections when said thread supply boundary is absent from said first and second circumferential sections, and said sensor means generating substantially identical first and second thread signals corresponding to a scanning property of said thread when said thread is disposed in said first and second circumferential sections;
• and
• control means connected to said sensor means which discriminates said non-identical first and second storage surface signals from said substantially identical first and second thread signals for controlling supplying of said thread supply to said storage surface in dependency upon the presence of said thread supply boundary within said first and second circumferential sections;
• whereby said scanning property of at least one of said first and second circumferential sections differs from said scanning property of said thread.