Method and apparatus for synchronously piecing roving for a continuous feeding thereof to a ring spinning frame

A method of synchronously piecing rovings for carrying out a roving bobbin exchanging operation between second roving bobbins in an almost exhausted condition and corresponding full packaged first roving bobbins, in a ring spinning frame which is provided with (a) a plurality of spindles arranged with an identical spindle pitch in an alignment along a lengthwise direction of said spinning frame at each side thereof, (b) a creel portion, (c) a plurality of draft parts arranged along said alignment of spindles at a position between said creel portion and said spindle alignment, said draft parts being positioned in relation to respective spindles and perpendicular to the lengthwise direction of said spindle alignment;

• a roving bobbin transporting system for introducing bobbin carriages to said creel portion of said spinning frame and for discharging said bobbin carriages therefrom, wherein said roving exchange operation is carried out between said almost exhausted second roving bobbin of said bobbin carriage positioned at said creel portion of said ring spinning frame and corresponding ones of said full packaged first roving bobbins of another bobbin carriage carried to said creel portion of said spinning frame,
• said method comprising the steps of:
• synchronously reserving a leading free end of a roving taken from each one of a plurality of full packaged first roving bobbins at a position in proximity to a roving being fed from a corresponding one of a plurality of second roving bobbins until said second roving bobbins become almost exhausted, said reserving being done in a region generally upstream of feeding said roving to a corresponding one of said draft parts,
• synchronously feeding said reserved leading free end of a roving from said full packaged first roving bobbin together with a tail end portion of said roving from a corresponding one of said second roving bobbins, which is feeding to said draft part, in a doubled condition, at a time immediately before said tail end portion of said roving from said second roving bobbin is fed into said draft part;
• thereby carrying out a synchronous piecing operation of said leading free end of said roving taken from said one of said full packaged first roving bobbins with said tail end position of said roving from a corresponding one of said almost exhausted second roving bobbins, while a spinning operation of said spinning frame is carried out.

An apparatus for providing a synchronous roving piecing operation when carrying out roving bobbin exchanging operation between almost exhausted roving bobbins and corresponding full packaged roving bobbins, in a ring spinning frame provided with (a) a plurality of spindles arranged with an identical spindle pitch in an alignment along a lengthwise direction of said spinning frame at each side thereof, (b) a creel portion, (c) a plurality of roller stands arranged on said spinning frame at a position between said creel portion and said spindle arrangement, (d) a plurality of pairs of two adjacent draft parts supported by said roller stands with a pitch identical to said spindle pitch at each side of said spinning frame with an alignment along said arrangement of said roller stands positioned so that said draft parts are oriented toward respective spindles in a direction perpendicular to the lengthwise direction of said spindle alignment, each one of said draft parts comprising a common front bottom roller and a front top roller rotatably contacting said front bottom roller under pressure, a common second bottom roller and a second top roller rotatably contacting said second bottom roller under pressure, a common back bottom roller and a back top roller rotatably contacting to said back bottom roller under pressure, said front, second and back top rollers of each pair of two adjacent draft parts provided with respective common shafts, a trumpet arranged at an upstream position of a feeding side in proximity to a contact line between said back top roller and said common back roller, (e) a plurality of top arm mechanisms each comprising a top arm for rotatably supporting said common shafts of the front, second back top rollers of each pair of two adjacent draft parts at their middle portions, a root end portion of said top arm pivoted to a corresponding one of said roller stands, means for respectively pressing each of said top arms against said common front, second and back bottom rollers during spinning operation, in combination with a transporting system for transporting bobbin carriages, each provided with a plurality of bobbin hangers for suspending the respective roving bobbins,

• said apparatus comprising:
• a plurality of bobbin carriage supporting rails disposed in parallel at said creel portion along a lengthwise direction of said spinning frame for covering an entire length of said spinning frame, said supporting rails at least temporarily supporting said bobbin carriage for supplying rovings to corresponding draft parts of said spinning frame during a spinning operation of said spinning frame, and at least temporarily supporting said bobbin carriage for suspending a plurality of full packaged roving bobbins before carrying out said roving piecing operation,
• a supplemental roving feed roller disposed at a position behind the alignment of said trumpets on a feeding side of said rovings to said respective draft parts, in parallel alignment to the alignment of said draft parts,
• means for selectively rotating said supplemental roving feed roller,
• means for stopping said supplemental roving feed roller,
• a plurality of adjacent pairs of nip rollers arranged along said supplemental roving feed roller at respective positions thereabove so as to be capable of contacting said supplemental roving feed roller,
• means for supporting said adjacent pairs of nip rollers so as to be alternately rotated and stopped,
• said supporting means comprising a plurality of bifurcate levers, corresponding to each side of each of said top arms, having two free end portions and pivotably mounted at a position therebetween to each of said top arms, a horizontal shaft rigidly mounted on one of said two free end portions of said bifurcate lever at a middle portion thereof so that each pair of said adjacent pairs of nip rollers are mounted on respective portions projected to both sides of the respective top arm,
• means for synchronously pressing said adjacent pairs of nip rollers to said supplemental roving feed roller,
• guide means for selectively guiding a pair of rovings from said almost exhausted roving bobbin and a corresponding one of said full packaged roving bobbins so that one of said pair of rovings is introduced to said intervening space between two adjacent nip rollers, while another one of said pair of rovings is introduced to a space between one of said two nip rollers and said supplemental feed roller, and
• means for reciprocally displacing said guide means along said spindle alignment for a distance to carry out selective guiding of said pair of rovings thereby.