Method and apparatus for tufting uniform cut pile

[57] ABSTRACT

A tufting looper mechanism including a looper element or hook and a knife member having blades or cutting edges disposed on opposite sides of each looper element, and means for reciprocably moving the looper element and knife edges relative to each other for cutting a yarn loop held by the looper element in two different places to form cut pile yarn ends of equal height.

Claims, 9 Drawing Figures

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PATENTED Μ 16 ere

3,662.697

SHI [I 1 OF 2

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PATENTED MAY 16 1972

3.662.697

Wass

Sil! ET 2 OF 2

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3,662,697

METHOD AND APPARATUS FOR TUFTING UNIFORM CUT PILE

BACKGROUND OF THE INVENTION

This invention relates to a tufting machine, and more particularly to a cut pile looper mechanism for a tufting machine.

Traditionally, cut pile has been produced in tufting machines by a reciprocable looper or hook engaging and holding a loop of yam carried through a base fabric by a reciprocable needle, and a reciprocable knife cooperating with one side of the looper to cut the loop of yarn into two separate strands. As the knife reciprocates along and against one side of the looper, the yam loop is cut on one side of the hook to form two unequal cut pile strands or ends. Such cutting is referred to in the industry as a “J-CUT,” because the long strand is Jshaped. Many manufacturers of cut pile fabrics, particularly carpets, have found the conventional “J-CUT” pile to be objectionable because of the unequal height of the pairs of strands in each cut loop, which presents an uneven pile surface.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide a method and an apparatus in the form of a novel looper mechanism including a looper element and knife member for cutting the loop yarns evenly to form cut strands or yarn ends in each loop of equal height.

This invention contemplates a looper mechanism for a multiple needle tufting machine incorporating looper elements or hooks and a knife member having a pair of knife edges cooperating with the opposite faces of each looper. The knife member may have various forms, so long as the pair of knife edges are disposed adjacent, and preferably against, the opposite faces of the looper elements, to cut the loop yarn held 35 by the looper element in two places equally spaced from the base fabric in order to provide a cut pile surface having cut loop strands of equal height.

One method of carrying out the invention is to provide a pair of knife blades whose knife edges are of equal height and 40 disposed on opposite sides of and against the opposite faces of a looper element or cut pile hook. The cut pile hook and the knife member are reciprocated relative to each other in a conventional manner to simultaneously double cut the loop yam.

In a modification of the invention, the thickness of each ⁴$ knife blade may be great enough to span the distance between each adjacent pair of cut pile hooks so that one knife will make two cuts, one cut on one side of one hook and another cut on the opposing face of the adjacent hook. In this manner, only half as many knives will be needed, and the thicker knives will provide lateral stability for not only the knives but also the looper elements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. I is a fragmentary sectional elevation of the portion of a tufting machine incorporating this invention, disclosing the looper mechanism in non-cutting position;

FIG. 2 is a view similar to FIG. 1 disclosing the looper mechanism in cutting position;

FIG. 3 is an enlarged fragmentary view taken substantially along the line 3—3 of FIG. 1;

FIG. 4 is a fragmentary perspective view of the looper mechanism made in accordance with this invention;

FIG. 5 is an enlarged sectional elevation of the base fabric 65 and a single loop cut in accordance with this invention;

FIG. 6 is a view similar to FIG. 1 of a modification of the invention;

FIG. 7 is a fragmentary front elevation of the looper mechanism disclosed in FIG. 6; 70

FIG. 8 is a fragmentary sectional elevation, somewhat similar to FIG. 2, of another modification of the looper mechanism; and

FIG. 9 is a fragmentary front view of the looper mechanism disclosed in FIG. 8. 75

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings in more detail, FIGS. 1 and 2 disclose a typical needle bar 10 supporting a plurality of nee5 dies 11 disposed in a row transverse of the tufting machine. The needle bar 10 is adapted to be reciprocably moved between its lower position disclosed in FIG. 1 and upper position in FIG. 2 by a push rod 12 driven by conventional means, not shown.

Supported upon a needle plate 13 for movement longitudinally from front to rear through the tufting machine is a base fabric 15. Each needle 11 carries a yam 16 through the base fabric 15 upon each stroke of the needle.

The looper mechanism made in accordance with this inven15 tion includes a plurality of looper elements or cut pile hooks 18 mounted transversely of the tufting machine upon the same gauge as the needles 11 in a hook bar 19 supported on the hook shaft 20 mounted for reciprocable movement, by means not shown, in a conventional manner.

The looper element or cut pile hook 18 includes a bill 22 having a free end 23 and an opposed throat 24. The entire hook 18 is preferably of a uniform thickness having smooth opposed faces 25 and 26 (FIG. 3).

Although the bottom face or surface of the bill of a conven25 tional cut pile hook 18 is chamfered or cut at an angle to provide a cutting edge to cooperate with the conventional single knife mounted on one side of the hook, nevertheless in this invention it is preferred that the bottom surface of the bill 22 be square or perpendicular to the opposed faces 25 and 26 of the 30 hook 18.

The looper mechanism made in accordance with this invention also includes a knife member 28 including a supporting bar or shank 29 mounted in a knife block or holder 30 which is fixed to the transverse knife shaft 31 adapted to be reciprocated, by means not shown, in a conventional manner. Mounted on the upper end of the shank 29 are a pair of flexible knives 32 and 33, the upper ends of which form the cutting edges 34 and 35. The knives 32 and 33 are mounted on opposite sides of the shank 29 so that they are slightly spaced apart to slip-fit on opposite sides of the cut pile hook 18. The knives 32 and 33 are also flexed toward each other so that the cutting edges 34 and 35 will be tensioned flush against the opposed faces 25 and 26 of the hook 18. Thus, the flexing of the knife blades 32 and 33 toward each other will assure a close fitting scissors action between each blade with respect to the opposed faces 25 and 26 of the hook 18. Accordingly, the blades 32 and 33 are preferably made of a flexible material, such as spring steel.

In the operation of the modification disclosed in FIGS. 1 4, the mechanism for reciprocating the push rod 12, hook shaft 20 and knife shaft 31, and for moving the base fabric 15 in the direction of the arrow, are the same as in any conventional tufting machine. Thus, in FIG. 1, the needle 11 has been moved to its lowermost position for carrying the yarn 16 through the base fabric 15, and the cut pile hook 18 and knife member 28 have been moved to their forwardmost position. In the forwardmost position, the bill 22 of the hook 18 has extended across the needle 11 to catch, engage and hold a loop 38 of yam. The cutting or knife edges 34 and 35 are in their lowermost positions below the bill 22 of the hook 18 in their non-cutting positions.

In the other extreme reciprocal position, as best disclosed in FIG. 2, the needles 11 are elevated above the base fabric 15, while the cut pile hook 18 reciprocates rearward holding the loop 38 upon the bill 22, as the base fabric 15 moves rearward. The knives 32 and 34 also reciprocate rearward, but also move upward relative to the cut pile hook 18 so that both cutting or knife edges 34 and 35 move above the lower edge of the bill 22 to sever the loops 38 caught upon the bill 22 of the looper 18 on previous strokes of the needle 11. Since each cutting edge 34 and 35 is cutting a piece of each yam loop 39 on opposite faces 25 and 26 of the cut pile hook 18, the yam is cut in two places so that each remaining leg or strand 70 and 71 of the loop 39 is of equal depth (FIG. 5), because the knife

3,662,697 edges 34 and 35 are equidistant below the base fabric 15. Of course, in cutting the loop 39 in two places, the bight portion 72 of the yarn between the cutting edges 34 and 35 is completely removed from the yam loop 39 and constitutes waste, as disclosed in FIG. 5.

In order to reduce waste, the thickness of the cut pile hook 18 may be reduced to a value less than is required for a conventional cut pile hook. Moreover, a thinner looper or cut pile hook 18 will permit narrower gauges for the transverse row of needles 11, and will also accommodate needles of more varying sizes. Furthermore, because each cut pile hook 18 has a knife blade 32 and 33 bearing with substantially equal pressure upon each side of the hook 18, the strength of a thicker hook is not required for lateral support, as it is in a conventional looper mechanism where a single knife presses against only one face of the hook.

As a further refinement of this invention, the knife edges 34 and 35 preferably converge toward the free end 23 to provide a better cutting action and also to reduce the binding effect of the knife blades 32 and 33 against the opposed faces 25 and 26. If the knife edges 34 and 35 were parallel, there would be a greater bearing surface between the knives and the hook faces 25 and 26, creating more wear and frictional drag between the knives and the hook.

FIGS. 6 and 7 disclose a modified form of knife member 48 ²³adapted to cooperate with the same needles 11, base fabric 15 and cut pile hook 18 employed with the previously described knife member 28.

The knife member 48 includes a plurality of J-shaped or hook-shaped knives 50 mounted at equally spaced intervals ³⁰transversely of the machine in a knife block 51 fixed to the conventional knife shaft 52, mounted for reciprocation by conventional means, not shown. Each knife 50 is of uniform thickness substantially equal to the spacing between each pair ,of adjacent hooks 18 so that each side of a knife 50 will bear against the opposed faces of adjacent hooks 18. One top corner edge 53 of a knife 50 forms one cutting edge for cooperating with one face of a hook 18, while the opposite top corner edge 54 of the same knife 50 forms a knife edge for ₄₀cooperating with the opposed face of an adjacent hook 18.

In this manner, one knife 50 functions as two cutting edges, as best disclosed in FIG. 7. Moreover, since each knife 50 occupies the entire space between opposed hooks 18, the knives 50 provide lateral support for the hooks 18 and also maintain 45 the hooks 18 as well as the knives 50 stabilized upon a uniform gauge. Otherwise, the knives 50 and their cutting edges 53 and 54 perform the same function as the knives 32 and 33 of FIGS. 1-4. The knife edges 53 and 54, being of equal height, cut each yearn loop 39 in two places on opposite sides of the hook 50 18 for forming yarn strands or ends 70 and 71 of equal height in each loop.

In the modification disclosed in FIGS. 8 and 9, a knife member 58 of different construction cooperates with a different, but conventional, loop pile hook 68, a plurality of 55 which are mounted transversely upon the uniform needle gauge in the hook bar 69 which is nounted for convenient reciprocable movement by known means. The knife member 58 comprises a solid, flat, block 59 of material, mounted by a bracket 60 upon a knife shaft 61 for reciprocable movement 60 in a conventional manner. The upper end of the block 59 has a plurality of transversely spaced slots 62, which are milled or otherwise formed to produce the knife fingers 64. The knives 64 function in the same manner as the knives 50. As a matter of fact, although the knives 64 are shown as being straight, 65 they may also be hook-shaped as the knives 50. The main difference between the knife member 58 and the knife member 48 is that the knives 50 are independent and may be individually removed and replaced in the block 51, while the 5 knives 64 are formed integrally with their supporting portion or block 59.

The loop 39 disclosed in FIG. 5 may be cut in two places by any of the knife members 28, 48, or 58 to form the two yarn strands 70 and 71 of equal height.