Needle unit for knitting machine

Abstract: A needle unit which is changeable in movement and which is free of friction loss while the needle body is moving up and down. It has a select jack (1), a push-up jack (2) and a needle body (3) arranged in a needle groove in this order from bottom to top. The needle body (3) has at its bottom a bifurcated portion made up of a support piece (9) and a resilient piece (10). The push-up jack (2) has its top end slidably inserted between the support piece (9) and the resilient piece (10), with the resilient piece (10) biased toward the push-up jack (2). The resilient piece is provided in its inner surface with two recesses (11,12) having different depths and on its outer surface with a butt (14). The push-up jack has a protrusion (8) on one side thereof adapted to engage in the recesses when the push-up jack slides up and down.

Description: BACKGROUND OF THE INVENTION This invention relates to a needle unit mainly for use in a weft knitting machine. Fig. 6 shows a conventional needle unit which comprises a needle body 72 having a hook 70 and a latch 71 for opening and closing the hook 70, a jack 73 coupled to the bottom of the needle body 72 and provided with a butt 75 on one side thereof, and a presser 74 pressed against one side of the jack 73 and provided with a butt 76 protruding in the same direction as the butt 75. This needle unit is inserted in each of a plurality of parallel needle grooves D2 formed in a needle bed B2. A carriage C2 is provided so as to move along the needle bed B2 in the direction in which the needle grooves D2 are arranged. It has a reference surface 81 facing the needle bed B2 and having two kinds of cams 82 and 83 adapted to engage the butt 75. The cams 82 and 83 differ in the degree of protrusion and the shape of the guide surfaces from each other. That is, the cam 83 protrudes more prominently from the reference surface 81 than the cam 82. The carriage C2 is provided with a solenoid 84 adapted to press the butt 76. When the carriage C2 is moved in the direction the needle grooves D2 are arranged with the butt 76 not pressed by the solenoid 84 as shown in Fig. 6, the butt 75, which is now protruding from the needle groove D2 to the maximum, is guided by the cam 82, so that the needle body 72 moves up and down together with the jack 73. When the carriage C2 is moved with the butt 76 pushed in one step by the solenoid 84 as shown in Fig. 7, the cam 83 guides the butt 75 to move the needle body 72 up and down together with the jack 73. Due to the different shapes of the cams 82 and 83, the needle body 72 is moved up and down by different degrees at different timings in the state shown in Fig. 7 than in the state shown in Fig. 6. When the butt 76 is pushed in further by the solenoid 84 until it retracts completely into the needle groove D2, the needle body 72 will not move up and down because the butt 75 is not in engagement with either of the cams 82 and 83. By varying the degree of protrusion of the butt 76 from the needle groove D2 with the solenoid 84, it is possible to control the movement of the needle unit and thus to form any desired stitch pattern. One problem with this conventional needle unit is that because the needle body 72 is moved up and down with the presser 74 pressed against the jack 73, a lot of energy is needed to move the carriage C2 overcoming the frictional resistance between the jack 73 and the presser 74. From DE-C1-3 523 989 and WO-A-9 004 669 needle units comprising spring shank needles are known. A resilient needle shank is biased toward the bottom of the related needle groove and is provided with a butt at the side facing the knitting cams. This butt protrudes from the needle groove and engages with the knitting cams dependent on the movement of a push-up jack engaging with the lower end of the resilient needle shank. An object of this invention is to provide a needle unit which is changeable in movement and which is free of friction loss while the needle body is moving up and down. SUMMARY OF THE INVENTION According to this invention, there is provided a needle unit for use in a knitting machine comprising a select jack, a push-up jack and a needle body arranged in a needle groove in this order from bottom to top, the push-up jack being adapted to be pushed up by raising the select jack, the needle body having at its bottom a bifurcated portion comprising a support piece and a resilient piece, the push-up jack having its top end slidably inserted between the support piece and the resilient piece, the resilient piece being biased toward the push-up jack, the resilient piece being provided in its inner surface with two recesses having different depths and on its outer surface with a butt, the push-up jack having a protrusion on one side thereof adapted to engage in and out of one of the recesses when the push-up jack slides up and down. Other features and objects of the present invention will become apparent from the following description made with reference to the accompanying drawings, in which: BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a partial vertical sectional side view of a first embodiment of the needle unit according to this invention, as mounted in a knitting machine; Fig. 2 is a sectional view taken along line II-II of Fig. 1; Fig. 3 is a sectional view taken along line III-III of Fig. 2; Fig. 4 is a sectional view taken along line IV-IV of Fig. 2; Fig. 5 is a sectional view taken along line V-V of Fig. 2; Fig. 6 is a partial vertical sectional side view of a conventional needle unit as mounted in a knitting machine; Fig. 7 shows its operational state; Fig. 8 shows its another operational state; Fig. 9 is a partial side view of a second embodiment of the needle unit according to this invention; Fig. 10 is a partial side view of a third embodiment; and Fig. 11 is a similar view of a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Embodiments of this invention are described with reference to the accompanying drawings. Referring to Fig. 1, the needle unit according to this invention is inserted in each of a plurality of parallel needle grooves D1 formed in the needle bed B1 and comprises a select jack 1, a push-up jack 2 and a needle body 3 arranged in this order from bottom to top. The select jack 1 has a lower, a middle and an upper butt 4, 5 and 6 at one side thereof. The butts 5 of the select jacks 1 in adjacent needle grooves D1 are longitudinally displaced from each other. On one side of the push-up jack 2, a butt 7 and a protrusion 8 are provided near its bottom end and at its intermediate portion, respectively. The needle body 3 has a bifurcated bottom portion comprising a support piece 9 and a resilient piece 10. The push-up jack 2 has its top end slidably inserted between the support piece 9 and the resilient piece 10. The resilient piece 10 is biased toward the push-up jack 2 and formed with recesses 11 and 12 in the inner surface near its bottom end. As the push-up jack 2 is moved up and down, the protrusion 8 is adapted to engage in the recess 11 or 12. The needle body 3 has a butt 13 on the outer surface of the resilient piece 10 near its bottom end and a butt 14 provided slightly over the base of the resilient piece 10 and protruding in the same direction as the butt 13. The recess 11 is deeper than the recess 12, so that when the protrusion 8 of the push-up jack 2 is received in the recess 11, the butt 13 protrudes one step from the needle groove D1, and when the protrusion 18 is in the recess 12, the butt 13 will protrude two steps from the needle groove D2. When the protrusion 8 is not received in either of the recesses 11 and 12, the butt 13 is completely retracted in the needle groove D1. The needle body 3 carries at its top end a hook 15 and a latch 16 for opening and closing the hook 15. A carriage C1 is provided to move along the needle bed B1 in the direction in which the needle grooves D1 are arranged. It has a reference surface 21 facing the needle bed B1 and having cams 22-38 as shown in Fig. 2. The cams 24, 28, 35 and 38 are protrudable from the reference surface 21. The cams 31 and 32 are variable in the degree of protrusion from the reference surface 21. The cam 34 is movable along a guide groove 39 formed in the reference surface 21. A solenoid 40 is provided on the portion between the cams 22 and 25 to press each butt 5. In Fig. 2, solid lines, chain lines and two-dot chain lines indicate the paths of butts 4, 6, 7, 13 and 14 when the needle unit performs knitting (forming a loop), tucking and forms no loop, respectively, as the carriage C1 is moved rightwardly with the left cam 24, right cam 28 and cam 38 retracted completely in the reference surface 21 and the cams 31 and 32 protruding to one step lesser degree than the other cams. In the case of knitting, as shown in Fig. 3, the right cam 23 guides the butt 4 to raise the select jack 1 and thus the push-up jack 2 until the protrusion 8 engages in the recess 11. The butt 13 thus protrudes one step from the needle groove D1. As the carriage C1 moves further right, the butt 4 is guided by the right cam 24 (Fig. 4), so that the select jack 1 rises further, pushing up the push-up jack 2 until the protrusion 8 engages in the recess 12. The butt 13 thus protrudes two steps from the needle groove D1. As the carriage C1 moves further right, the needle body 3 rises together with the push-up jack 2 with its butt 13 guided by the cams 31 and 32. The loop formed thus moves down past the latch 16, and a yarn is supplied to the hook 15. The butt 13 is then guided by the cams 35 and 34, so that the needle body 3 and the push-up jack 2 descend, disengaging the protrusion 8 from the recesses 11, 12. In the case of tucking, the carriage C1 is moved in the state shown in Fig. 3, with the butt 13 guided by the cam 30, so that the needle body 3 rises together with the push-up jack 2. Although a yarn is supplied to the hook 15, the loop formed will not come off the latch 16 because the needle body 3 does not rise so high relative to the needle bed B1 as when knitting. When no loop is formed, the butt 5 is pushed by the solenoid 40, as shown in Fig. 5, to retract the butt 4 completely into the needle groove D1, so that the select jack 1 and thus the push-up jack 2 do not rise. The protrusion 8 does not engage in either of the recesses 11 and 12. The carriage C1 thus moves with the butt 13 retracted in the needle groove D1, so that the needle body 3 does not rise from the needle bed B and no yarn is provided to the hook 15. Thus, no loop is formed. In order for the needle unit to perform the same function as above when the carriage C1 is moved leftwardly, the left cam 24 and the right cam 28 are protruded from the reference surface 21 with the right cam 24 and the left cam 28 retracted in the reference surface 21. By selectively protruding or retracting the cams 35 and 38, by varying the degrees of protrusion of the cams 31 and 32 from the reference surface 21, by varying the and 32 from the reference surface 21, by varying the position of the cam 34, and by changing the operating timing of the solenoid 40, it is possible to change the movement of the needle unit and thus to form different stitch patterns. As shown in Fig. 9, the needle body 3 may be divided into a needle member 50 having the hook 15 and the latch 16, and a support member 51 having the support piece 9 and the resilient piece 10. With this arrangement, if the resilient piece 10 is broken, it is necessary to replace only the support member 51. It is thus possible to reduce maintenance cost. As shown in Fig. 10, the support piece 9 and the resilient piece 10 may be separate members so that only the resilient piece 10 can be replaced. In the arrangement of Fig. 11, the resilient piece 10 is coupled to the support piece 9 through a movable joint 52 and is biased by a spring rod 53 toward the push-up jack 2. If the spring rod 53 is broken, it is necessary to replace only the spring rod 53. According to this invention, the amount of protrusion of each butt from the needle groove is adjusted by adjusting the distance the select jack is raised to change over the cams to be brought into engagement with the butts and thus to change the movement of the needle unit. The needle body is raised together with the push-up jack by engaging the protrusion in one of the recesses. Since no frictional resistance is produced, no large force is needed to raise the needle body. It is not necessary to provide the carriage with any additional mechanisms such as cams for guiding the push-up jack, so that the knitting machine can be manufactured at low cost. In the arrangement in which the needle body is divided into a needle member and a support member provided with the support piece and the resilient piece, if the resilient piece is broken, it is necessary to replace only the support portion. Repair costs are thus low.

Claims: A needle unit for use in a knitting machine comprising a select jack (1), a push-up jack (2) and a needle body (3) arranged in a needle groove (D1) in this order from bottom to top, said push-up jack (2) being adapted to be pushed up by raising said select jack (1), characterised by said needle body (3) having at its bottom a bifurcated portion comprising a support piece (9) and a resilient piece (10), said push-up jack (2) having its top end slidably inserted between said support piece (9) and said resilient piece (10), said resilient piece (10) being biased toward said push-up jack (2), said resilient piece (10) being provided in its inner surface with two recesses (11, 12) having different depths and on its outer surface with a butt (13), said push-up jack (2) having a protrusion (8) on one side thereof adapted to engage in and out of one of said recesses (11, 12) when said push-up jack (2) slides up and down. A needle unit as claimed in claim 1 wherein said needle body (3) is divided into a needle member (50) and a support member (51) having said support piece (9) and said resilient piece (10).

Inventors: IKENAGA KATSUYOSHI, IKENAGA, KATSUYOSHI
Applicants: IKENAGA CO LTD, IKENAGA CO., LTD.
Application year: 1996
Main classification: D04B15
IPC codes: D04B15