Sliver drafting apparatus

In a drafting apparatus for drafting a sliver in a yarn spinning machine, said drafting apparatus comprising upper and lower inlet rollers, upper and lower apron belts, upper and lower apron belt guides, and upper and lower outlet rollers, wherein said upper apron belt passes around said upper inlet roller and said upper apron belt guide, and wherein said lower apron belt passes around said lower inlet roller-and said lower apron belt guide and cooperates with said upper apron belt to define an inlet nipping area between said belts for nipping the fiber sliver as it passes between said upper and lower inlet rollers while being sandwiched between said upper and lower apron belts, said sliver being nipped in said nipping area and being subsequently directed by said belts to a nip formed between said upper and lower outlet rollers, and wherein a nose region of one of said upper and lower apron belt guides, around which one of the apron belts is deflected extends closer up to the inlet and outlet rollers than the other nose region of the other one of said upper and lower apron belt guides, around which the other apron belt is deflected, the improvement wherein said upper and lower apron belt guides have curved apron belt engaging surfaces over at least substantially the full length of contact with the respective apron belts as the belts pass from said upper and lower inlet rollers towards said nose region, and wherein the upper and lower apron belt guides cooperate to define a generally S-shaped path for said sliver from said inlet nipping area to the nip of said upper and lower outlet rollers, both of said apron belts lying substantially parallel to one another over at least the first curve of said S-shaped path following said nipping area, said sliver being guided thereafter by at least one apron belt.

A drafting apparatus having an apron zone for drafting a sliver in a yarn spinning machine comprising:

• an apron drafting mechanism comprising a pair of upper and lower apron inlet rollers forming a first nipping area, an upper and a lower apron, an upper guide having a forward nose for engaging the upper apron, a lower guide having an upper surface and a forward nose for engaging the lower apron and a pair of upper and lower sliver delivery rollers forming a second nipping area;
• the upper apron travelling around the upper inlet roller and the forward nose of the upper guide, and the lower apron travelling around the lower inlet roller, over the upper surface and around the forward nose of the lower guide;
• the upper and lower aprons being resiliently pressed against each other such that a sliver may be delivered between the first and second nipping areas with the sliver sandwiched under the pressure between the aprons;
• the upper and lower guides engaging the pressed together upper and lower aprons such that the sliver, during the course of travel between the first and second nipping areas, is substantially deflected in at least one upward direction out of the straight line path between the nipping areas and is also substantially deflected in at least one downward direction out of the straight line path between the nipping areas such that the sliver path between the first and second nipping areas is substantially S-shaped.