Warp knitting machine

Abstract

An improved warp knitting machine employing compound needles and an interconnected trick-sinker mechanism which maintains a fixed relationship with the knitting needles and tends to hold the knitted fabric in line with the back guide bar to lessen the stress on the knitting needles. Each of the guide bars include a hollow guide tube to guide the warp yarn to a point closely adjacent the top of the knitting needle to reduce the necessary vertical stroke of the knitting needles.

Description

The knitting speed of a knitting machine, the tendency to require considerable repair and the defects on the fabric being produced is partially dependent on the stroke of the knitting needles necessary to knit the yarn being supplied thereto.

Therefore it is an object of the invention to provide an improved knitting machine with a yarn guide system which reduces the required vertical stroke of the knitting needles.

Other objects and advantages of the invention will become readily apparent as the specification proceeds to describe the invention with reference to the accompanying drawings, in which:

FIG. 1 represents a partially schematic side elevation view of the new, improved warp knitting machine;

FIG. 2 is a side elevation view of the novel combination trick-sinker mechanism;

FIG. 3 is a view taken on line 3--3 of FIG. 2;

FIG. 4 is a blown-up view showing in detail the relationship of the guide bars and the knitting needle;

FIG. 5 is a schematic representation of the yarn guide tubes and their relation to the knitting needle;

FIG. 6 is a front view of a guide tube support plate;

FIG. 7 is a view taken on line 7--7 of FIG. 6; and

FIG. 8 is a modification of the guide tubes shown in FIG. 5.

Looking now to FIG. 1, the reference numeral 10 represents the new and improved warp knitting machine which is conventionally driven by a machine crankshaft (not shown). The crankshaft coordinates and drives the push rods 12 to pivot the needle base 14 around the shaft 16 to reciprocate the compound needles 18. The push rods 20 pivot the sinker bar 22 to impart slight rotational movement of the trick-sinker 24 to coordinate its movement with the needles 18 and the guide bars 26, the movement of which is controlled by the guide bar rocker arm 28. In conventional manner, the guide bar rocker arm is driven by a suitable connection to the knitting machine crank shaft. The warp fabric 30 knit at the needles 18 is delivered to the take-up roll (not shown) by suitable rolls 32, 34, 36 and 38.

The combination trick-sinker 24 allows the knitting machine 10 to knit any fabric that can be knit on a tricot or raschel warp knitting machine but has eliminated the necessity for certain moving parts on such machine resulting in increased knitting machine speed up to at least 1500 courses/minutes. For example, the sinker and the latch wires of the raschel machine has been eliminated while the presser bar of the tricot machine has been eliminated. The trick-sinker 24 moves with the guide bars 26 and maintains a pre-determined relationship with the needles 18 and the sinker throat 40 of the thin plate members 41 to hold the knitted fabric 30 on the trick band 42 to allow the needles 18 to cast off the previously knit course but prevent the fabric 30 from moving with the needles 18 as they are retracted. Further, the trick band 42 of the trick-sinker 24 is so positioned to maintain an acute angle "A" of approximately 27 degrees with the vertical axis of the needles in order to align the knitted fabric 30 with the yarn from the back guide bar in order to maintain minimum stress and tension on the needles 18 to minimize breakage of needles and yarns.

The operation of the knitting machine 10 is basically as described in U.S. Pat. No. 4,202,185, except that the knitting needles on the upward stroke do not project upward above the yarn guide tubes 44 secured in the yarn guide tube support plate 46. The guide tubes 44 provide control of the yarn so that the compound needles 18 only move up to a point closely adjacent the bottom of the tubes 44. By closely adjacent, it is meant that the distance between the line 48, denoting the bottom position of the tubes 44 and the line 50, denoting the top positions of the needle 18 is on the order of 15-20 thousandths of an inch (FIGS. 5 and 8). This distance will vary depending on the machine gauge, type of yarns and fabric construction.

Each of the guide bars 26 support a plurality of yarn guide tube support plates 46 by suitable means such as screws 52 projected through the opening 54 and screwed into the plate 46. As shown in FIG. 6, the plate 46 holds a plurality of hollow yarn guide tubes 44 of suitable material such as stainless steel. The tubes 44 are pressed into the plate 46 and held therein by friction. An elongated opening 56 is provided in each plate 46 to provide visual and physical contact with the yarn and tubes in the plate 46 and/or adjacent plates 46.

In the preferred form of the invention as shown in FIGS. 1-7, the tube 44 is cut so that the bottom edge is parallel to the top edge which is perpendicular to the centerline of the tube (FIG. 5). If it is desired to provide closer control of the yarn passing through the tube 44, the tube can be formed so that the bottom edge of the tube commingles with the line 48 as shown in FIG. 8. This construction allows contact with the warp yarn at a point closer to the needle 18 than in the construction shown in FIG. 5.

As indicated in U.S. Pat. No. 4,202,185 increased operating speeds have been obtained by the use of the combined trick-sinker 24. Further, increases in speed are provided by the use of the tube guides since the use of same reduces the upward stroke of the needle 18 and the swing or stroke of the guard bar assembly 28 by approximately 65%. This reduction of the stroke of the needles and guide bar assembly allows the yarn to be directed closely adjacent to the needle thereby reducing the amount of yarn that is pulled through the guide bars from the warp beams on each knitting cycle. This action results in reduced scuffing of the yarn by the guide bars which in turn results in less machine stops due to yarn abrasion and/or breakage. Further, the guide tubes 44 require substantially less maintenance than the commonly used yarn guide member and reduces the amount of defects produced in the knitted fabric. Therefore, the disclosed invention provides a better fabric at a higher speed with reduced maintenance time and cost required.

Although I have described the preferred embodiment of my invention, I contemplate that changes may be made without departing from the scope or spirit of the invention and I desire to be limited only by the scope of the claims.

Claims

1. A method of warp knitting a fabric on a warp knitting machine having a combination trick-sinker, a plurality of needles and a plurality of guide bars with guide tubes therein which have their terminus above the uppermost position of the needles comprising the steps of: supplying warp yarn to the plurality of guide bars, forming a course of loops, raising the needles of the warp knitting machine to the uppermost position through the formed course of loops, moving the guide bars to the most forward position, guiding the warp yarn from the guide bar through the terminus of the guide tubes to a point above and adjacent the top of the needles in the uppermost position, moving the needles downward through the previously formed loops, allowing the previously formed loop to be cast off, continue to move the needles to the lowermost position and moving the guide bars to the extreme rearward position ready to knit the next course of fabric.