Yarn tension control for a tufting machine

Claim 2

In a tufting machine for forming a pile fabric including a plurality of tufting needles mounted for reciprocation between a raised position and a lowered position, power means for reciprocating said needles in unison between said raised and lowered positions, means for guiding a yarn along a path of travel to each needle, and looper means operatively associated with each needle for forming successive tufting loops from the yarns, the combination therewith of means for stopping the reciprocation of said needles with said needles in a predetermined position substantially corresponding to said raised position of said needles, and means positioned along said path of travel for tensioning said yarns during movement of the associated needles from their lowered to their raised position and while the tufting loops are held by said looper means to thereby tighten the tufting loops about said looper means, and for relaxing said yarns when said needles occupy said predetermined position whereby the machine may be stopped in said predetermined position for threading or other purposes without causing stop marks on the pile fabric caused by the yarns being tensioned during stoppage of the needles.

Claim 3

The tufting machine as defined in claim 1 wherein said stopping means comprises electrically controlled clutch means for disabling said power means, electrically controlled brake means for stopping reciprocation of said needles when said power means is disabled, and switch means for automatically actuating said clutch means and brake means when said needles are in a preselected position such that the reciprocation of said needles will stop when said needles reach said predetermined position.

Claim 4

In a tufting machine for forming a pile fabric including a plurality of tufting needles mounted for reciprocation between a raised position and a lowered position, power means for reciprocating said needles in unison between said raised and lowered positions, means for guiding a yarn along a path of travel to each needle, and looper means operatively associated with each needle for forming successive tufting loops from the yarns, the combination therewith of means positioned along said path of travel for selectively varying the tension on each yarn during each reciprocation of the associated needle such that the yarn is tensioned during movement of the associated needle from its lowered to its raised position to thereby tighten the tufting loops about said looper means, and tHe yarn is relaxed when the needle is positioned substantially at its raised position, said means for selectively varying the tension on each yarn comprising a pair of spaced guide members fixedly carried by said machine, at least one movable guide member positioned intermediate said spaced guide members, and means operatively associated with said power means for moving said movable guide member in timed relation to the operation of said machine such that the yarn path of travel is alternately lengthened and shortened by the movement of said movable guide member, said means for moving said movable guide member including a first shaft mounted for rotation about a first axis and mounting said movable guide member, a second shaft mounted for rotation about a second axis extending generally parallel to said first axis, means for continuously rotating said second shaft in timed relation to the operation of said machine, a cam having a predetermined peripheral outline fixedly carried by said second shaft for rotation therewith, and a follower fixedly carried by said first shaft and operatively engaging said cam peripheral outline whereby the rotation of said second shaft causes said follower to selectively oscillate said first shaft and said movable guide member, and means for stopping the reciprocation of said needles in a predetermined position wherein said needles are positioned substantially at their raised position and the yarns are relaxed, whereby the machine may be stopped for threading or other purposes without causing stop marks on the pile fabric caused by the yarns being tensioned during stoppage of the needles.

Claim 5

In a tufting machine for forming a pile fabric including a plurality of tufting needles mounted for reciprocation between a raised position and a lowered position, power means for reciprocating said needles in unison between said raised and lowered positions, means for guiding a yarn along a path of travel to each needle, and looper means operatively associated with each needle for forming successive tufting loops from the yarns, the combination therewith of means positioned along said path of travel for selectively varying the tension on each yarn during each reciprocation of the associated needle such that the yarn is tensioned during movement of the associated needle from its lowered to its raised position to thereby tighten the tufting loops about said looper means, and tHe yarn is relaxed when the needle is positioned substantially at its raised position, said means for selectively varying the tension on each yarn comprising a pair of spaced guide members fixedly carried by said machine, at least one movable guide member positioned intermediate said spaced guide members, and means operatively associated with said power means for moving said movable guide member in timed relation to the operation of said machine such that the yarn path of travel is alternately lengthened and shortened by the movement of said movable guide member, said means for moving said movable guide member including a first shaft mounted for rotation about a first axis and mounting said movable guide member, a second shaft mounted for rotation about a second axis extending generally parallel to said first axis, means for continuously rotating said second shaft in timed relation to the operation of said machine, a cam having a predetermined peripheral outline fixedly carried by said second shaft for rotation therewith, and a follower fixedly carried by said first shaft and operatively engaging said cam peripheral outline whereby the rotation of said second shaft causes said follower to selectively oscillate said first shaft and said movable guide member, and means for stopping the reciprocation of said needles in a predetermined position wherein said needles are positioned substantially at their raised position and the yarns are relaxed, whereby the machine may be stopped for threading or other purposes without causing stop marks on the pile fabric caused by the yarns being tensioned during stoppage of the needles.

Claim 6

A tufting machine as defined in claim 3 wherein said means for rotating said second shaft includes a third shaft mounted for rotation about a third axis extending generally parallel to said first axis, means operatively associated with said power means for continuously rotating said third shaft, means operatively connected between said second and third shafts for rotating said second shaft in accordance with the rotation of said third shaft, and means for manually adjusting the relative spacing of said first and second shafts whereby the extent of the oscillation of said follower and thus the first shaft and movable guide member may be varied.

Claim 7

The tufting machine as defined in claim 4 wherein said means for manually adjusting the relative spacing of said first and second shafts comprises a lever arm mounted for independent movement about said third axis and extending radially therefrom, said lever arm mounting said second shaft in spaced relation to said third axis, and means for manually adjusting the position of said lever arm about said third axis whereby said second shaft may be moved toward or away from said first shaft.

Claim 8

The tufting machine as defined in claim 5 wherein said means for manually adjusting the position of said lever arm includes a female threaded member carried by one of said lever arm and machine, a male threaded member rotatably carried by the other of said lever arm and machine and threadedly engaging said female member, and crank means for rotating said male threaded member.