Spinning plant with roving frames and ring-spinning frames

A spinning plant comprising:

• at least one roving frame having a multiplicity of stations for forming roving from sliver and winding roving onto a respective core sleeve at each of said stations and form a respective roving bobbin;
• at least one ring spinning frame having a multiplicity of stations for spinning roving from said bobbins into yarn and emptying roving from the core sleeves of said bobbins;
• an endless transport element extending in a closed path between said at least one roving frame and said at least one ring spinning station for carrying roving bobbins to said ring spinning frame from said roving frame and for returning empty core sleeves from said ring spinning frame to said roving frame, said empty core sleeves having one of a plurality of different colors representing different roving qualities of roving bobbins to be wound thereon;
• at least one automatic transfer unit along said path and provided with means for exchanging core sleeves and roving bobbins on said transport element for empty core sleeves;
• and
• at least one color sensor along said path for automatic scanning of said empty core sleeves for color and, in dependence upon a detected color, controlling operation of said transfer unit
• at least one filling sensor for distinguishing between substantially full roving bobbins, substantially empty core sleeves and empty hanger positions of said transport element and controlling said at least one automatic transfer unit activation of said color sensor, said filling sensor being located upstream of said color sensor with respect to the direction of movement of said roving bobbins and empty core sleeves along said path and being connected to said color sensor for activating same.

A method of operating a spinning plant comprising:

• at least one roving frame having a multiplicity of stations for forming roving from sliver and winding roving onto a respective empty core sleeve at each of said stations and form a respective roving bobbin;
• at least one ring spinning frame having a multiplicity of stations for spinning roving from said bobbins into yarn and emptying roving from the core sleeves of said bobbins;
• an endless transport element extending in a closed path between said at least one roving frame and said at least one ring spinning station for carrying roving bobbins to said ring spinning frame from said roving frame and for returning empty core sleeves from said ring spinning frame to said roving frame, said empty core sleeves having one of a plurality of different colors representing different roving qualities of roving bobbins to be wound thereon;
• at least one automatic transfer unit along said path and provided with means for replacing roving bobbins on said transport element with empty core sleeves;
• and
• at least one color sensor along said path for automatic scanning of said empty core sleeves for color and, in dependence upon a detected color, controlling operation of said transfer unit, said method comprising the steps of:
• (a) advancing each hanger position of said transport element from which a full roving bobbin or an empty core sleeve can be suspended to arrive in sequence at a sensing station;
• (b) upon arrival of each hanger position at said sensing station, detecting with said color sensor whether an empty core sleeve of a certain color or a roving bobbin of a certain roving quality has arrived;
• and
• (c) thereafter activating a filling sensor of a respective automatic transfer unit to control operation of the transfer unit.

A method of operating a spinning plant comprising:

• at least one roving frame having a multiplicity of stations for forming roving from sliver and winding roving onto a respective empty core sleeve at each of said stations and form a respective roving bobbin;
• at least one ring spinning frame having a multiplicity of stations for spinning roving from said bobbins into yarn and a emptying roving from the core sleeves of said bobbins;
• an endless transport element extending in a closed path between said at least one roving frame and said at least one ring spinning station for carrying roving bobbins to said ring spinning frame from said roving frame and for returning empty core sleeves from said ring spinning frame to said roving frame, said empty core sleeves having one of a plurality of different colors representing different roving qualities of roving bobbins to be wound thereon;
• at least one automatic transfer unit along said path and provided with means for exchanging core sleeves and roving bobbins on said transport element;
• and
• at least one color sensor along said path for automatic scanning of said empty core sleeves for color and, in dependence upon a detected color, controlling operation of said transfer unit, said method comprising the steps of:
• (a) detecting for each hanger position with a filling sensor capable of distinguishing between full roving bobbins, empty core sleeves and empty hanger positions, whether the respective hanger position has an empty core sleeve;
• and
• (b) thereafter activating the color sensor which is located downstream of the filling sensor in a direction of displacement of said transport element when an empty core sleeve is in the respective hanger position.