The movement of the single jersey machine's settling plate is controlled by its triangular configuration, while the settling plate serves as an auxiliary device for creating and closing loops during the weaving process. As the shuttle is in the process of opening or closing loops, the jaws of the sinker act akin to the two lateral walls of the needle groove on a double-faced loom, blocking the yarn to allow the shuttle to form a loop and push the old loop away from the mouth of the shuttle when the shuttle completes its loop. To prevent the old loop from remaining stuck at the top of the shuttle's needle as it rises and retracts, the sinker's jaws must use their fangs to push the old loop away from the fabric's surface, and maintain a grip on the old loop throughout the shuttle's rise and retreat to ensure that the loop is completely removed. Thus, the position of the sinker's jaws significantly impacts the technological position of the sinker during weaving, which, in turn, affects the weaving process. From the role the sinker plays during weaving, it can be seen that before the shuttle rises and retraces its loop, the sinker's jaws should push the old loop away from the top of the needle. In terms of the distance from the thread to the loom, as long as the warp is placed in the back of the needle, it can avoid the phenomenon of new threads piercing through or bursting old threads when the needle rises. If pushed too far, the descent of the new web will be blocked by the jaws of the sinker, causing the weaving not to proceed smoothly, as shown in Figure 1.
1,Theoretically speaking, when the sinker’s jaws rise up and down in the weaving cycle, they should merely touch the back line of the needle as it rises, allowing for a smooth descent. Any further advancement would disrupt the settling arc of the new loop, thereby affecting the weaving process. However, in practice, it is not sufficient to merely select the position of the settling cam when the jaws of the sinker meet the line of the needle. Several factors can influence its placement.
2,Of late, the most prevalent single jersey machine settling plates with curved corners can be categorized into two types, as depicted in Figure 4. In Figure 4a, the dashed line is an arc that intersects the angle S on the sinker plate with its center coinciding with the center of the needle If the needle bar line is set as the reference for installing the drop-in cams, then during the entire process of running through curve 4a, where the weaving needles end their loop formation and begin to unwind, until they reach their highest point and finish unwinding, the drop-in cams' jaws should remain in alignment with the needle bar line. From a microscopic perspective, it can be seen that the actual new coil sagging arc always surpasses the needle-back line in the tiger's mouth, thus causing the new coil sagging arc to be constantly under stress during the weaving process. When weaving delicate fabrics, the impact of large diameter thread loops is yet to be noticeable. Yet, when weaving thick fabrics, it is all too easy for flaws such as holes to appear due to the small circumference of the loops. Therefore, the choice of this type of curve’s drafting cam technique cannot be based on the standard of matching the tiger mouth with the needle and thread behind it. Upon actual installation, a certain distance should be withdrawn outward from the line of the tiger's mouth and needle.
3,In Figure 4h, if the gauge is adjusted to align with the needle back line at point T, the gauge should remain in place until the shuttle begins to move up from the loop formation until it reaches its highest point. During this process, the gauge's mouth should be positioned outside the needle back line, except for when it coincides with the needle back line as the shuttle starts rising. At this time, the points on the new coil's sagging arc, even if momentarily subjected to load, would not significantly affect weaving due to mutual transfer of force between the strands. Therefore, for the curve depicted in Figure 4b, the selection of the position for the trapezoidal plates to enter and exit should be based on the installation criterion that the trapezoidal plates shall be aligned with the needle's back line upon adjustment at the workshop.
From a microeconomic perspective
4,The shape of the tiger's mouth in the settling plate is a semicircular net arc, with one end of the arc coinciding with the blade jaw. As depicted in Figure 2, the weaving process involves a curve of the yarn on the plate jaw. Before the shuttle completes its loop and begins to rise to the level of the plate jaw, if the sinker plate is pushed down to align with the needle line, the new loop's descent arc does not lie at the deepest point of the sinker plate but rather somewhere along the curved surface between the sinker plate and the plate jaw, as depicted in Figure 3. This point is distant from the needle line, and the settling of the new coil is subjected to load here unless the cleft shape is rectangular, in which case it may align with the needle line.The unaccounted-for descent of the triangular curve of the settling plate .At present, the most prevalent single jersey machine sinking plate curve cams in the market can be roughly categorized into two types, as depicted in Figure 4. In Figure 4a, the dashed line is an arc that passes through the center of the syringe and cuts across the cam S on the settling plate.
5, If the needle bar line is set as the benchmark for installing the sinking plate cams, then throughout the entire process of running along curve 4a in Figure 4a, from the moment the weaving needles finish their weft thread to the point where they exit the loop until the highest point is reached and the loop is finished, the sinking plate's jaws shall always remain in alignment with the needle bar line. From a microscopic perspective, it can be seen that the actual new coil's sagging arc always surpasses the needle knot line in the tiger mouth, thereby causing the new coil's sagging arc to always be under load during the weaving process. When weaving delicate fabrics, the impact is not yet apparent due to the large loop length. Yet, when weaving thick fabrics, small loop lengths can easily result in imperfections such as holes. Thus, when selecting the sewing pattern for such curves, the standard cannot be set by aligning the tiger mouth with the needle line. Upon installation, the needle should be placed slightly outward from the tiger's mouth, in line with the back line.
In Figure 4b, if the mouth of the tiger is adjusted to align with the needle back line, from the moment the weaving needle begins to unwind the warp thread until it reaches its highest point before descending, the slotted mouth of the tiger, except for its position coinciding with the needle back line when the weaving needle begins to rise (i.e., at T), will be positioned ten millimeters outside the needle back line, that is, from the top of the tiger's mouth to the needle back line. At this juncture, the point of the new coil's sagging arc, even if momentarily subjected to force, would not significantly affect the weaving due to the mutual transfer of forces between the coils. Therefore, for curve 4b, the selection of the position for the sinking plate cams to enter and exit should be based on the installation reference point where the sinking plate cams shall be set to align with the needle line and the back line of the sinker at T.
Changes in the serial number of the three machines
6,A change in the machine number implies a variation in the needle pitch, which is reflected on the fabric as a change in the sagging arc of the weft threads. The longer the settling arc length, the higher the machine number; conversely, the shorter the settling arc length, the lower the machine number. And as the machine number increases, the line density allowed for weaving decreases, with the strength of the yarns being lower and their lengths shorter. Even slight forces can alter the shape of the loop, particularly in weaving polyurethane fabrics.
Post time: Jun-27-2024