Method of constructing double fleec knit fabric using circular knitting machine

Abstract: A method for constructing a double fleece knit fabric using a circular knitting machine is disclosed. Lay-in, tie-in and knit-in yarns (57, 58 and 59) are fed at respective first, second and third yarn feeders (60, 61 and 62) to the needle. The lay-in and tie-in yarns (57, 58) are caught by the outward, oblique and upward recession of the sinker. The knit-in yarn (59) is fed to the needle (2) and when received onto the upper edge (8g) of the second nose (8e) is drawn down onto the upper edge (8f) of the first nose (8d) of the sinker (8) when the needle (2) is lowered. The needle (2) is lowered to a stitch loop forming position while the sinker (8) is receded from the innermost lower position to the outermost upward position so that the knit-in yarn (59) falls onto the stitch forming ledge (8a) and the respective lengths of the tie-in yarn (58) and knit-in yarn (59) in the needle hook are drawn downward with the older tie-in and knit-in loops being cleared from the needle (2) so as to form a new tie-in loop and knit-in loop over the stitch forming ledge (8a).

Description: This invention relates generally to a method of constructing a double fleece knit fabric on a circular knitting machine adapted to feed respectively a lay-in yarn, a tie-in yarn, and a knit-in yarn to the needles, and more particularly, to such a method wherein a first lay-in yarn, a second tie-in yarn, and a third knit-in yarn are fed to a knitting machine having sinkers for engaging the yarn, and with each sinker including a stitch forming ledge, a first nose portion with an upper edge, a first open throat, and a second nose portion above and rearward of the first nose portion to define a second open throat and with the sinkers obliquely movable from an innermost lower position to an outermost upper position during knitting to aid in forming a double fleece knit fabric. In most single unit knitting machines used to construct a double fleece knit fabric, three yarn feeders are provided to feed respectively a lay-in yarn, a tie-in yarn and a knit-in yarn to the needles. Production rates, however, have been limited. For example, in a circular knitting machine having a 762 mm (30 inch) diameter cylinder and 72 yarn feeders, only 24 courses per revolution are attainable. Recently, a 30 inch diameter knitting machine having 90 yarn feeders has been manufactured to improve productivity. In this machine, a needle of short latch length is used together with a sinker having a nose which is positionally low. Additionally, a sharper inclination of the raising cam and stitch cam is provided to increase productivity. However, in this machine, when the rotation speed exceeds 200 rpm, excessive wear of the butts of the needles occurs and the sinker can break in a short period of time. Attempts to overcome the aforementioned problems of the prior art have been limited. For example, a needle of shorter latch length has been used for making more gentle the inclination angle of the cylinder cam and sinker cam. Additionally, the yarn length which is drawn in per stitch at the tie-in yarn feeder is reduced. The sinker top (stitch formation face) is positioned lower for making a more gentle inclination angle of a cam, and thereby, reducing the vertical distance of needle movement at the lay-in, tie-in and knit-in yarn feeders. It has been determined, however, that the reduced angle of inclination of the cam causes a drop stitch or missed stitch when a mistake is made in the adjustment of the needle for a short latch length. Also, the reduction in the length of the yarn to be drawn in for the tie-in stitch makes it impossible to obtain a fabric of rough stitch density. DE-A-2318196 describes a sinker for a circular knitting machine used to construct single fleece knit fabric, the sinker having two noses, two throats and upper and lower stitch-forming surfaces. It is an object of this invention to provide a method of constructing a double fleece knit fabric by the use of a circular knitting machine equipped with multi-yarn feed and which enables the inclination angles of the cylinder cam and sinker cam to be made more gentle without sacrificing needle and sinker durability. The invention consists in a method of constructing a knit fabric on a circular knitting machine adapted to feed a lay-in yarn, a tie-in yarn and a knit-in yarn to latch needles, the knitting machine having sinkers obliquely movable from an innermost lower position to an outermost upper position, and wherein each sinker includes a stitch forming ledge, a first nose with an upper edge and a first open throat, and a second nose above and rearward of the first nose to define a second open throat having an upper edge thereon, the method comprises the steps of (a) feeding a first lay-in yarn to a raised needle having a tie-in loop and knit-in loop thereon while obliquely receding a sinker from the innermost lower position to the outermost upper position to receive the lay-in yarn at the upper edge of the first nose, (b) lowering the needle to raise the tie-in loop and knit-in loop onto the needle stem and close the latch onto the lay-in yarn, while also advancing the sinker in an inwardly declining direction, (c) raising the needle to open the needle latch and transfer the lay-in yarn onto the needle stem while also obliquely advancing the sinker to the innermost lower position so that the second throat on the sinker pushes the lay-in yarn (57) to retain the lay-in yarn thereat, (d) feeding a tie-in yarn to the needle hook, (e) lowering the needle hook while also obliquely receding the sinker so that the lay-in yarn closes the needle latch, (f) raising the needle to clear the loop of the lay-in yarn from the needle while advancing the sinker to the inner lower position so that the tie-in yarn is received by the upper edge of the first nose and is transferred downwardly onto the needle stem, (g) feeding a knit-in yarn to the needle hook when the needle has reached a raised position so that the knit-in yarn also is received by the upper edge of the second nose, (h) lowering the needle while obliquely receding the sinker so that the knit-in yarn which is received onto the upper edge of the second nose is drawn down onto the upper edge of the first nose, and (i) further lowering the needle to a stitch loop forming position while receding the sinker from the innermost lower position to the outermost upper position so that the knit-in yarn falls onto the stitch forming ledge of the sinker and the respective lengths of the tie-in yarn and knit-in yarn in the needle hook are drawn downward with the older tie-in and knit-in loops being cleared from the needle so as to form a new tie-in loop and knit-in loop over the stitch forming ledge. In order that the invention may be more readily understood, a particular embodiment will now be described by way of example with reference to the accompanying drawings in which:- Figure 1 is a vertical sectional view through the needle cylinder of the knitting machine and illustrating the manner in which the sinkers are mounted for oblique sliding movement relative to the needles; Figure 2 is a side elevational view of one of the special type of sinkers utilized in the present invention; Figure 3 is a somewhat schematic developed elevational view showing the paths of travel of the needles and associated sinkers at the respective first, second and third yarn feeding positions; Figures 4-14 are side elevations of the upper portions of the needles and associated sinkers being taken along respective section lines 4-14 of Figure 3 and showing their relationship during the successive steps of forming the double fleece knit fabric and shedding the previously formed tie-in and knit-in loops from the needles; and Figure 15 is a side elevation of the upper portion of the needle and the sinker showing their relationship when the sinker is advanced to draw the old tie-in and knit-in loops from the needle. Referring now to Figure 1, a rotating needle cylinder 1 is supported on a driven ring gear 12. The outside surface of the needle cylinder 1 is provided with the usual needle slots 1a in which hook latch needles 2 are supported for vertical movement parallel to the axial rotation of the needle cylinder 1. Each knitting needle 2 is provided with an operating butt, as indicated at 2a (Figure 1), and a pivoted latch 2b (Figure 4). Conventional knitting cams, including a control cam 4 are provided for imparting vertical movement to the knitting needles 2. The control cam 4 is supported by a cam holder 3 fixed to the upper surface of a cam ring plate 5. A sinker nose support ring 6 is fixed on the upper inner surface of the needle cylinder 1 and is provided with a downwardly inclined surface 6a defined by the lower surfaces of sinker slots 6b provided in the upper end of the sinker nose support ring 6. A sinker support bed 7 is fixed to the exterior of the upper end of the needle cylinder 1 and is provided with a downwardly inclined sinker sliding surface 7a defined by the lower ends of sinker slots formed in the sinker bed 7 and at the same downwardly inclined angle as a sinker sliding surface 6a of the sinker nose ring 6. Special types of sinkers, broadly indicated at 8 in Figure 2, cooperate with the needles 2 to form stitch loops and are supported for movement in a radial direction and along a downwardly inclined path of travel between the needles 2. Inward and outward radial sliding movement of the sinkers 8 along the downwardly inclined path of travel, is controlled by sinker cams 10 supported in a fixed position on a sinker cap 9. Sinker cap 9 is supported on a sinker cap support ring 11 which is supported in spaced-apart locations on the upper ends of support standards 13 surrounding the needle cylinder 1. The sinker cams 10 are supported in a downwardly inclined position at the same downwardly inclined angle as the inclined sliding surfaces 6a and 7a on the respective nose ring 6 and sinker bed 7. The sinker sliding surfaces 6a and 7a are illustrated in Figure 1 as being downwardly inclined at an angle of 20° relative to a line perpendicular to the vertically disposed needles 2. While this 20° downwardly inclined angle is preferred, the present invention is not limited to this particular angular inclination but may be positioned at an angle from 5° to 60°, and preferably within the range of 10° to 45°. Four to six yarn carrying supports 14 are supported by and extend upwardly and inwardly from the sinker cap support ring 11. A yarn carrier ring 15 is fixed on the inner ends of the yarn carrying supports 14. Yarn guides, broadly indicated at 16, are fixed to the underside of the yarn carrier ring 15 and are provided with a holder 17 and yarn feed carriers 60, 61 and 62 for feeding yarns to the needles 2, in a manner to be discussed (Figure 3). As best shown in Figure 2, the special sinker 8 includes an elongate body portion having a main, lower planar sliding edge 8j adapted to rest upon and slide along the inclined surface 7a of the sinker bed 7, and an inner lower additional planar sliding edge 8b adapted to rest on and slide along the inclined sliding surface 6a of the sinker nose ring 6. A stitch forming ledge 8a is provided on the upper inner portion of the sinker and extends horizontally thereto. A first neb or nose 8d extends inwardly and over the outer portion of the stitch forming ledge 8a and defines a first open throat 8c between the nose 8d and the stitch forming ledge 8a. An upper edge 8f is provided on the nose 8d for controlling lay-in and tie-in yarns. A second neb or nose 8e is provided above and rearward to the first neb 8d and defines a second open throat 8h having an upper edge 8g thereon. An upstanding operating butt 8k extends upwardly at a right angle from the body portion of the sinker 8. The butt 8k is engaged by the sinker cams 10 to impart the required inward and outward radial movement to the sinkers 8. In conventional sinkers, the stitch forming ledge extends along a line which is parallel with the lower planar sliding ledge of the sinker. In contrast to this conventional construction, the present special type of sinker 8 is characterized by the stitch forming ledge 8a being slanted downwardly toward the operating butt 8k on the outer end portion of the elongate body portion of sinker 8. The angle of declination defines an acute angle of about 20°. Thus, the downwardly inclined or outwardly slanting stitch forming ledge 8a of the sinker 8 of the present invention is different from the normal type of sinker in which the stitch forming ledge extends parallel to the lower planar sliding edge of the sinker. Referring now to Figure 3, there is shown a schematic representation of the loci of movement for the paths of travel of needles and associated sinkers. The transverse solid line 50 indicates the upper edge of the inclined sliding surface 6a of the sinker nose ring. The continuous solid line 51 shows the locus of movement of the upper tip of the hook of the needle 2. The alternate, long and dashed line 52 indicates the locus of movement of the second sinker throat 8h. The alternate, long and dashed line 53 indicates the locus of movement of the first sinker throat 8c. The dotted line 54 indicates the locus of movement of the upper edge 8g of the second nose or neb 8e. The dotted line 55 indicates the locus of movement of the upper edge 8f of the first nose 8d. The dotted line 56 indicates the locus of movement of the sinker stitch forming ledge 8a. Respective first, second and third yarn carriers 60, 61, and 62 are provided to feed the respective lay-in, tie-in and knit-in yarns, 57, 58 and 59 to the needles 2. As the needles successively approach the first yarn feeder 60, as shown in Figure 3, they are successively raised to the clearing level along the solid line 51 and to a position where the previously formed loops in the needle hook are lowered and open the latch 2b so as to slide down on the stem, whereupon the needle reaches the highest clearing position. At the same time, the sinker begins receding from the innermost position to an outward, oblique upper position. While the needles 2 are in a raised, latch clearing position, a first lay-in yarn 57 is fed to the raised needle in which the older tie-in loops and knit-in loops are retained on the stem (Figure 5). The needle 2 lowers to catch and retain the lay-in yarn 57 which has been fed from the yarn carrier 60 (Figure 6). The sinker 8 obliquely recedes from the innermost lower position to the outermost upper position to receive the lay-in yarn 57 at the upper edge 8f of the first sinker nose 8d. The needle is further lowered so that the tie-in and knit-in loops retained on the needle stem rise thereon and close the latch onto the recently fed lay-in yarn 57 (Figure 7). At this time, the sinker advances in an inwardly declining direction so that a length of the yarn for a lay-in loop is obtained by slightly pushing the lay-in yarn 57 into the needle hook with the second throat 8h. At the second yarn feeder 61, the needle rises to a position higher than the first feeder 60 (Figure 8). At this position, the lay-in yarn 57 in the needle hook is moved below the tip of the latch 2b and transferred to the needle stem (Figure 8). At the second yarn feeder 61, a tie-in yarn 58 is fed to the hook of the needle 2. The needle hook is lowered so that the lay-in yarn 57 is turned to the rear of the latch 2b to close the latch and catch the tie-in yarn 58 therewithin (Figures 9-10). As the needle 2 is lowered, the sinker 8 is advanced in an inward, oblique lowered direction from the outward, oblique upper recessive position. As the sinker advances, it receives the tie-in yarn 58 at the upper edge 8f of the first nose 8d. With further lowering of the needle, the lay-in yarn 57 is cleared from the needle and a required length of the tie-in yarn 58 is received by the upper edge 8f of the first step nose and then is drawn downward. The old loops remain in a forward position in the needle hook. At the third yarn feeder 62, the needle rises to a position lower than first and second feeders (Figure 11), and the tie-in yarn 58 held therewithin opens the latch. At this position, the tie-in yarn 58 is positioned in an approximate middle point of the latch 2b, and the sinker 8 is positioned in an inward, oblique, and downward direction from the position shown in Figure 9. A knit-in yarn 59 then is fed from the yarn carrier 62. The needle is lowered and catches and retains the knit-in yarn 59 therewithin (Figure 12). The knit-in yarn 59 also is received by the upper edge 8g of the second nose 8e. As the needle is further lowered, the knit-in yarn 59 on the upper edge of the second nose 8e is lowered and the latch is closed (Figure 13). The tie-in yarn 58 on the latch is again caught in the needle hook and a required length of the knit-in yarn 59 is drawn downward onto the upper edge of the first nose 8d (Figure 14). At this time, the sinker 8 has moved from the most advanced position on the inward, oblique lower side to a position from which the sinker 8 starts receding in the outward, oblique and upward direction. As shown in Figure 3 depicting the loci of movement for the needles 2 and sinkers 8, after the knit-in yarn 59 has been fed to the needle, the needle slightly rises and then lowers again. The sinker 8 recedes in the outward, oblique and upward direction from the position depicted in Figure 11 and the tie-in yarn 58 and knit-in yarn 59 on the upper edge 8f of the first nose smoothly fall onto the sinker stitch forming ledge 8a (Figure 14). The tie-in yarn 58 and knit-in yarn 59 are drawn downward and clear the old loops from the needle 2. The needle begins to rise (Figure 15) and the sinker begins to advance in an inwardly declining direction. When the needles 2 reach the highest position, the loops of the tie-in yarn 58 and knit-in yarn 59 open the latch 2b, leave the latch tip, and slide down on the stem as shown in Figure 5. The described cycles of this knitting operation are repeated to construct a double fleece knit fabric. The present method has advantages over the prior art because the inclination angles of the cylinder cam and sinker cam at the feeders for the lay-in, tie-in and knit-in yarns can be made more gentle. Thus, a reduced cam pitch prevents wear and breakage of the needle butt and sinker butt. Also, a double fleece knit fabric of excellent plating quality can be obtained because the knit-in loop and tie-in loop in the needle hook are positionally stable during knitting. Additionally, compound needles instead of latch needles may be used to accomplish the method.

Claims: A method of constructing a knit fabric on a circular knitting machine adapted to feeds a lay-in yarn (57), a tie-in yarn (58) and a knit-in yarn (59) to latch needles (2), the knitting machine having sinkers (8) obliquely movable from an innermost lower position to an outermost upper position, and wherein each sinker (8) includes a stitch forming ledge (8a), a first nose portion (8d) with an upper edge (8f) and a first open throat (8c), and a second nose portion (8e) above and rearward of the first nose portion (8d) to define a second open throat (8h) having an upper edge (8g) thereon, the method comprises the steps of (a) feeding a first lay-in yarn (57) to a raised needle (2) having a tie-in loop and knit-in loop thereon while obliquely receding a sinker (8) from the innermost lower position to the outermost upper position to receive the lay-in yarn (57) at the upper edge (8f) of the first nose (8d), (b) lowering the needle (2) to raise the tie-in loop and knit-in loop onto the needle stem and close the latch (2b) onto the lay-in yarn (57), while also advancing the sinker (8) in an inwardly declining direction, (c) raising the needle (2) to open the needle latch (2b) and transfer the lay-in yarn (57) onto the needle stem while also obliquely advancing the sinker (8) to the innermost lower position so that the second throat (8h) on the sinker (8) pushes the lay-in yarn (57) to retain the lay-in yarn (57) thereat, (d) feeding a tie-in yarn (58) to the needle hook, (e) lowering the needle hook while also obliquely receding the sinker (8) so that the lay-in yarn (57) closes the needle latch, (f) raising the needle (2) to clear the loop of the lay-in yarn from the needle while advancing the sinker (8) to the inner lower position so that the tie-in yarn (58) is received by the upper edge (8f) of the first nose (8d) and is transferred downwardly onto the needle stem, (g) feeding a knit-in yarn (59) to the needle hook when the needle (2) has reached a raised position so that the knit-in yarn (59) also is received by the upper edge (8g) of the second nose (8e), (h) lowering the needle (2) while obliquely receding the sinker (8) so that the knit-in yarn (59) which is received onto the upper edge (8g) of the second nose (8e) is drawn down onto the upper edge (8f) of the first nose (8d), and (i) further lowering the needle (2) to a stitch loop forming position while receding the sinker (8) from the innermost lower position to the outermost upper position so that the knit-in yarn (59) falls onto the stitch forming ledge (8a) of the sinker (8) and the respective lengths of the tie-in yarn (58) and knit-in yarn (59) in the needle hook are drawn downward with the older tie-in and knit-in loops being cleared from the needle (2) so as to form a new tie-in loop and knit-in loop over the stitch forming ledge (8a). A method according to Claim 1 including the step of obliquely moving the sinker (8) so that the stitch forming ledge (8a), the upper edge (8f) of the first nose (8d), and the upper edge (8g) of the sinker (8) move obliquely with respect to the needle (2) and intersect the needle (2) at all times at a right angle. A method according to Claim 1 or 2 wherein the stitch forming ledge (8a), the upper edge (8f) of the first nose (8d) and the upper edge (8g) of the second nose (8e) are in the lowest position when the sinker (8) advances to the innermost lower position, and the stitch forming ledge (8a), the upper edge (8f) of the first nose (8d) and the upper edge (8g) of the second nose are in the highest position when the sinker recedes to the outermost upper position. A method according to claim 1, 2 or 3, including feeding successive groups of the lay-in, tie-in and knit-in yarns to the needles.

Inventors: KAWASE SHINJI, YORISU SHOZO, KAWASE, SHINJI, YORISU, SHOZO
Applicants: PRECISION FUKUHARA WORKS LTD, PRECISION FUKUHARA WORKS, LTD
Application year: 1990
Main classification: D04B9
IPC codes: D04B15, D04B9