Looper of tufting machine

Abstract: Looper for a tufting machine proposed to improve the yarn cutting performance with a knife (7) in resilient contact with the looper. The knife abutting surface is bent about 2 degrees with respect to the handle (1) toward the knife (7).

Description: This invention relates to a looper of a tufting machine for tufted carpets. As shown in Figs. 3 and 4, a looper is a flat steel plate having a substantially Z-shape and comprising a handle 11 to be attached to a tufting machine, a stem 12, a yarn engaging rod 13 and a hook 14. A rectangular knife 15 slides up and down in contact with the right side face of the looper, kept inclined at an angle β (Fig. 4), to cut pile yarns 16 hooked on the yarn engaging rod 13. This looper has a yarn guiding recess 17 on one side of the yarn engaging rod 13 opposite to the side facing the knife 15. Because of provision of this recess, the looper is liable to get bent in a direction away from the knife due to stress produced during quenching. If this occurs, the knife would not abut the looper properly during tufting, so that thick yarns (e.g. those of more than 5000 denier) cannot be cut at all. Failure to cut occurs even with small-diameter yarns. Tufted carpets with such a bent looper will not be attractive to the eye because the cut pile surfaces are uneven. Further, such a bent looper will require higher motor power because the contact pressure for a cutting knife has to be increased. The greater the contact pressure or contact area between the knife 15 and the yarn engaging rod 13, the higher the frictional resistance therebetween tends to be. Thus, the looper will be more quickly worn and the pile yarns might be broken or fuse. The document GB-A-1 143 342 discloses a looper assembly for use in a tufting machine, the loopers lie at an angle relative to the looper bar as to be capable of presenting the centre of a loop to a cutting knife. If does not solve the problem that inaccurate cutting may occur. It is therefore an object of this invention to provide a looper for use in a tufting machine with which the knife can come into contact more reliably and which insures a clear cut with the knife. According to this invention, a knife abutting surface formed on one side of the stem, yarn engaging rod and the hook is bent by about 2 degrees with respect to the handle of the looper toward a knife which is disposed on one side of the looper. Since the looper is bent slightly toward the knife, the knife can be kept in resilient and close contact with the looper while sliding on the looper, with the contact area therebetween kept to a minimum. This makes it possible to concentrate the yarn cutting energy on the cutting point. Further, since the frictional resistance is lower, frictional heat produced is kept to a minimum. Sliding like scissors, the knife is kept in close contact with the looper, with the contact area therebetween kept to a minimum. Thus, the cutting energy can be concentrated on the cutting point, so that a clear cut is possible even a rather thick yarn, which could not be cut with a conventional looper. Further, the looper of this invention can maintain its high performance without the need of fine adjustment of the knife position. Due to low frictional resistance, yarns can be cut at higher speed with less motor power. The frictional heat can be limited to a minimum. This eliminates melting and fusing of the cut pile yarns at their tips, so that a beautiful cut pile surface is obtainable. Other features and objects of the present invention will become apparent from the following description made with reference to the accompanying drawings, in which: Fig. 1 is a side view of the looper for use in a tufting machine according to this invention, showing it in use; Fig. 2 is a plan view of the same; Fig. 3 is a perspective view of a conventional looper in use; and Fig. 4 is a plan view of the same. As shown in Figs. 1 and 2, the looper for use in a tufting machine according to this invention is a flat steel plate having a substantially Z-shape as viewed from side and comprising a substantially rectangular handle 1, a substantially trapezoidal stem 2 extending from the front end of the handle 1, a substantially rectangular yarn engaging rod 3 integral with the stem 2, and a hook 4 integral with the rod 3. The knife abutting surface 5 on the looper is bent from a line 6 at the front end of the handle 1 toward a knife 7 or rightwardly by an angle which is about 2 degrees. The knife abutting surface 5 is formed with a cutting edge 8 on the front edge of the stem 2, a cutting edge 8a on the bottom edge of the yarn engaging rod 3 and a cutting edge 8b on the rear edge of the hook 4. On the side opposite to the knife abutting surface is formed a moderately sloped yarn guiding recess 9. The line 6 at the front end of the handle 1 and the bottom edge of the yarn engaging rod 3 are substantially perpendicular to each other. The angle α, that is, the bending angle may be determined according the intended use. By attaching the handle 1 of this looper to the needle bed of a tufting machine, its stem 2, yarn engaging rod 3 and hook 4 will protrude from the needle bed so as to be inclined toward the knife by an angle of about 2 degrees with respect to the direction in which pile yarns are fed. This arrangement and the inherent resiliency of the looper, formed of a thin steel plate, ensure that the knife be pressed resiliently and tightly against the looper.

Claims: A looper for use in a tufting machine, said looper cooperating with a knife (7) disposed at one side of the looper to cut pile yarns (16), said looper comprising a handle (1), a stem (2), a yarn engaging rod (3) and a hook (4), a knife abutting surface (5) being formed on one side of said stem (2), yarn engaging rod (3) and hook (4), said knife abutting surface (5) being bent with a predetermined angle (α) with respect to said handle (1) toward the knife (7) characterized in that said angle (α) is an angle of about 2 degrees suitable for keeping the looper in a scissor-like sliding contact with said knife.

Inventors: YOSHINO SOTA, YOSHINO, SOTA
Applicants: NARA COMPANY LTD, NARA COMPANY, LTD.
Application year: 1993
Main classification: D05C15
IPC codes: D05C15