Sytem for exchanging roving bobbins applied to a ring spinning frame

A method for exchanging roving bobbins applied to a ring spinning frame in a spinning room wherein a plurality of spinning frames are installed, in combination with a system for transporting said roving bobbins between said spinning room and a roving room having a plurality of roving frames installed therein, wherein said spinning frame is provided with a plurality of draft parts arranged at each side thereof and a creel portion for positioning roving bobbins at a position above said arrangement of said draft parts, said roving bobbin transporting system utilizes a plurality of roving bobbin carriages, for holding roving bobbins from which rovings are applied to respective draft parts at each side of said spinning frame when said bobbin carriage is transported to a working position thereof at said creel portion of said spinning frame, said method comprising:

• providing a number of said roving bobbin carriages, each provided with two parallel alignments of said bobbin hangers arranged along a lengthwise direction thereof, such that a number of said bobbin hangers of each alignment of said bobbin carriages is equal to half of the number of said draft parts arranged along an entire length of one side of said spinning frame,
• arranging first and second supporting passages in parallel at a position right above said creel portion of each side of said spinning frame along the lengthwise direction thereof, said first passage for supporting a first one of said bobbin carriages and said second passage for supporting a second one of said bobbin carriages,
• introducing a first bobbin carriage, supporting full packaged roving bobbins by said bobbin hangers, to either one of said two supporting passages, by way of said roving bobbin transporting system, while a second bobbin carriage having roving bobbins, from which rovings are supplied to a corresponding one of said draft parts, is supported by the other of said supporting passages,
• first carrying out said roving bobbin exchange operation between said full packaged roving bobbins of said first bobbin carriage and subsequently carrying out a roving bobbin exchange operation with a corresponding one of said roving bobbins of said second bobbin carriage when said roving bobbins of said second bobbin carriage reach an almost exhausted condition after creating a tail end of a roving being supplied to a corresponding one of said draft parts by cutting said roving from a corresponding one of said almost exhausted roving bobbin, and piecing said tail end of said roving with a leading end of a corresponding one of said full packaged roving bobbin supported by a fresh one of said bobbin carriages,
• moving said second bobbin carriage by way of said roving bobbin transporting system, back to said roving room while said first bobbin carriage is supplying rovings to said draft parts,
• wherein a unit operation of introducing said first bobbin carriage to one of said supporting passages in combination with said roving bobbin exchange operation is alternately applied to said two supporting passages without stopping the production of said spinning frame.