Knit run cam

Abstract: A knit run cam for moving a needle vertically when fabrics are knitted comprises two cams (26A,26B) each having a needle butt lowering inclined surface which overlap over at least a part of the range of movement in the same phase with a carriage moving in a given direction, one of the cams having a needle butt lowermost position which is higher than the other said cam.

Description: The present invention relates to a knit run cam system for moving a needle vertically when fabrics are knitted. A needle for knitting fabrics is known which is moved up and down by placing a needle butt projecting from the needle in contact with a cam for vertically moving a needle provided on a carriage, and vertically moving the needle as the carriage moves. In the case of a needle having only one butt, a needle not having been lowered by a knitting cam for lowering the needle is lowered by a further succeeding guide cam, and therefore the number of needles required by the carriage increases, and as a result the load increases. Since the needle is not lowered to a resting position until the needle is not lowered by a succeeding guide cam, a stitch presser bar which moves along a mouth portion of a needle bed together with the carriage needs to cover the range thereof, so that the stitch presser bar itself has to be long, resulting in a cause of trouble. In the past, for example in the case of fabrics having intersha patterns, the knitting of a boundary of the patterns is tack knitted stitches having a standard size, and the following knitted portion is knitted with stitches having a standard size. Therefore, an unfavourable external appearance unavoidably occurs in that a loop in the boundary of the patterns is greatly opened. In DE-A-1560902 there is described a knit run cam system comprising two cams. Here, the needle butt is raised to the uppermost position by the cam 10, the needle is lowered by the cam 16, and then the needle butt is further lowered by the cam 11, if the carriage is moved to the right. Accordingly, when knit stitches and tack stitches are formed in the same course, both the needles for processing the knit stitches and the needles for processing the tack stitches are lowered to the same position, with the result that the lowering distance of the needle butt for the tack stitch cannot be decreased. Thus, if there are needles for knit stitches and needles for tack stitches in the same course, both sets of needles are lowered by the same stitch cams 11, 12. Therefore, the size of the knitting loops of the knit stitches and of the tack stitches cannot be selectively changed. Again, in BE-A-366267, both the needles for processing the knit stitches and the needles for processing the tack stitches are lowered to the same position and the loop size of the stitches cannot be changed. FR-A-606887 shows a construction for determining whether loops are to be formed or not in the next course. Knitting loops having different sizes cannot be formed. In view of the foregoing, it is an object of the present invention to relieve the load when a knitting needle is lowered, at the time of knitting by a one-butt needle, to remove one cause of trouble occurring by shortening the stitch presser, and to be able to produce four sizes of knitted stitches, i.e. tack stitches, knitted stitches, stitches of standard size and small size, respectively. In accordance with the invention there is provided a knit run cam system comprising: a knitting needle having a needle butt, a knitting cam having a needle butt lowering inclined face and a lowermost end, wherein the needle butt of the knitting needle engages the needle butt lowering inclined face and the lowermost end to form knit and tack stitches, and wherein said knitting cam has a recess and a fixed guide cam having a needle butt lowering inclined face and a lowermost end extension for engagement with the needle butt of the knitting needle to form tack stitches of decreased density, wherein the needle butt lowering inclined face and the lowermost end extension of said fixed guide cam overlap in said knitting cam such that the lowermost end extension of said fixed guide cam is spaced from the lowermost end of said knitting cam. The knitting needle is moved upwards to a knitting position by a lifting cam, and, after the feed of yarn, the needle is lowered to the lowermost position by the knitting cam. The tack needle is disengaged from the knitting cam, when it is lowered from the tack position, without being lowered to the lowermost position by the knitting cam, and is lowered by the knitting cam and by a lowering cam having a needle butt lowering inclined surface which overlaps in a range of at least a part in the same phase of a cam plate in a moving direction of the carriage. In order that the invention may be fully understood, one presently preferred embodiment in accordance with the invention will now be described by way of example and with reference to the accompanying drawings. In the drawings: Fig. 1 shows an arrangement of a knit run cam with a cam lock provided on a cam plate of a carriage viewed from the underside; Fig. 2 is a side view of a needle comprising a select jack, a selector and other parts; Fig. 3 is a plan view of a stitch cam control device; and Fig. 4 is a front view of the stitch cam control device of Fig. 3. Fig. 1 shows the position where a cam lock 1 of a carriage is viewed from the underside. Fig. 2 is a side view of a needle 2, a select jack 3, a selector 4, a select jack presser 5 and other components placed at positions corresponding in alignment to the cam lock 1. The needle 2 used in the knitting apparatus according to the present invention comprises a compound needle which is designed so that a slider 7 is slidably inserted into an upper portion of the needle at the extreme end of a needle body 6, and a slider butt 8 can be actuated so that a hook 9 of the needle body 6 can be opened and closed by the slider 7. Reference numeral 10 designates a needle butt provided on the needle body 6. A select jack butt 11 is provided at its base with recesses 12, 13 and 14. Each of the recesses 12, 13 and 14 is engageable with a wire 15 provided through a needle bed (not shown) to define positions of the select jack butt 11. The select jack butt 11 assumes a welt position when the wire 15 engages recess 12, assumes a tack position when engaging recess 13 and assumes a knit position when engaging recess 14. The select jack presser 5 comprises a ]-shaped elastic plate which is designed so that the upper edge thereof is brought into a web 16 inserted through a needle bed (not shown) to press against the select jack 3 at the end thereof and urge the select jack butt 11 in an upward direction. Reference numeral 17 designates a selector butt of the selector 4. The cam lock 1 comprises a knitting lock 22 and a transfer lock 23 provided on a cam plate 21. The knitting lock 22 comprises a lifting cam 24 of generally trapezoidal shape, with two inclined surfaces which serve as lifting cam surfaces 24a and 24b; a trapezoidal centre cam 25 having an angle-recess cam 25a provided on the same centre line as the lifting cam 24; left and right knitting cams 26A and 26B which are slidably provided in a /\-shape on respective sides of the centre cam 25; a crescent-shaped slider guide cam 27 provided at an upper level of the centre cam 25; and slider guide cams 29A and 29B provided on each side of the slider guide cam 27 to guide the butt 8 of the slider 7, along with a guide cam 28, moved upwards by the slider cam 27. The transfer lock 23 comprises a trapezoidal stitch transfer lifting cam 30 positioned near the top of the trapezoidal lifting cam 24 and having a height sufficient to move the needle 2 up to a stitch transfer position; a stitch receiving needle lifting cam 33 slidably provided within a depression 32 formed with an inclined frictional surface 31 in the central portion of the lifting cam 24; and the centre cam 25 which also comprises a part of the knitting lock 22. Reference numeral 34 denotes a fixed guide cam. Below the lifting cam 24 are provided a pair of pressers 35A and 35B acting on the select jack butt 11 when in the knit position to urge the butt 10 of the needle 2 down to a half position; a pair of pressers 36A and 36B acting on the select jack butt 11 when in the tack position to urge it down; a presser 37 positioned in the middle therebetween; and a presser 38, which is wider than the width of the lifting cam 24, acting on the select jack butt 11 when in the welt position. Next, the construction of the knitting cam 26 will be described. The knitting cams 26A and 26B are symmetrically supported on the lifting cam surfaces 24a and 24b of the lifting cam 24 so that the cams may be slidably moved up and down with respect to the cam plate 21. In the following, the knitting cam 26B will be described. The knitting cam 26B has a surface facing the lifting cam surface 24b of the lifting cam 24, said surface serving as a loop-forming lowering cam surface 26a. A central portion of the cam 26B comprises a recess 41, which constitutes a bevel 42 from a portion positioned slightly inwardly of the loop-forming lowering cam surface 26a towards the recess 41. The lower end following the lowering cam surface 26a is formed with a shoulder 43 having a height at which the butt at a half-height position can pass through, and the needle having the butt at the half-height position is lowered to the shoulder. The needle having a butt at the full-height position is lowered to the lowermost end 44 so that fabrics whose density varies can be knitted. An extending portion 45 extending into the recess 41 of the knitting cam 26B is provided on the fixed guide cam 34. The extending portion 45 has one side which serves as a lowering cam surface 45a for tack, said lowering cam surface 45a being parallel with the loop-forming lowering cam surface 26a of the knitting cam 26B. In the knitting cams 26A and 26B, the elevating means is symmetrically formed. Therefore, a stitch cam control device 50 of the knitting cam 26B will be described hereinafter. The cam plate 21 is formed with a slot 51 for obliquely upwardly moving the knitting cam 26B, a sliding member 52 being slidably fitted in the slot 51. The knitting cam 26B and a keeper member 53 are fixed integrally with the sliding member 52, to the lower surface and to the upper surface of the sliding member 52 respectively. A stitch cam control motor 56 is mounted through a motor mounting plate 55 on an inverted ]-shaped base bed 54 provided on the upper surface of the cam plate 21. A stitch cam control cam 59 having a spiral cam groove 58 is mounted on a motor shaft 57 of the stitch cam control motor 56. A cam follower 61 provided on a stitch cam control lever 60 is fitted into the cam groove 58. The stitch cam control lever 60 is pivotally supported on a shaft 63 within a recess 62 of the base bed 54. The cam follower 61 is supported on the central portion thereof and a holding lever 64 is supported by a shaft 65. The extreme end of the holding lever 64 comes into contact with a bent portion 66 at the extreme end of the stitch cam control lever 60, and a cam follower 67 supported on the upper surface of the keeper member 53 is.held by the holding lever 64 and the stitch cam control lever 60. A spring 68 is provided between the other end of the holding lever 64 and the stitch cam control lever 60 so that the holding lever 64 and the bent portion 66 at the extreme end of the stitch cam control lever 60 are always in contact with each other to constitute a shock absorbing mechanism. Reference numeral 69 designates a proximity sensor for detecting a zero position of the stitch cam control cam 59 so that when a projecting portion 70 of the stitch cam control cam 59 comes near, the sensor detects that projection and knows the zero position to stop the stitch cam control motor 56. The zero position is that where the cam follower 61 being fitted in the cam groove 58 of the stitch cam control cam 59 is at the centre of the cam 59, that is, the position close to the motor shaft 57, and the projecting portion 70 of the stitch cam control cam 59 is close to the proximity sensor 69. At this time, the knitting cam 26A is in the uppermost position, and the stitch cam control device 50 is as shown in Fig. 3 so that conversely the knitting cam 26B is in the lowermost position. Next, the knitting operation will be described. In knitting fabrics, it is assumed that the carriage is moved in the direction indicated by the arrow in Fig. 1. Selection of the knit, tack and welt positions of the needle 2 in the knitting process is accomplished by conventional known means. The select jack butt 11 corresponding to the needle for raising to the knit position assumes a height position of I. At that time, the pressers 35A and 35B determine function or non-function according to the density of the fabrics to be knitted. That is, in knitting for the standard density, the pressers 35A and 35B are withdrawn so as not to act on the select jack butt 11. The butt 10 of the needle comes into contact with the lifting cam surface 24a of the lifting cam 24 and moves upwards along the cam surface 24a as shown in Fig. 1 (I′). At that time, the stitch transfer lifting cam 30 goes down and therefore the needle butt 10 does not come into contact with the cam 30 but moves to the top 24C of the lifting cam 24. During that period, the slider butt 8 also moves as indicated by the Fig. 1 line I″, and when the slider butt 8 is at the lower edge straight line portion 29a of the slider guide cam 29B, the extreme end of the slider 7 is disengaged from the hook 9 due to the difference in upward movement between the needle body 6 and the slider 7, thereby to open the hook 9. Yarn is fed to the hook 9 of the needle 2 which has passed through the top 24C of the lifting cam 24 and the top 27C of the slider guide cam 27. As the carriage advances, the needle butt 10 contacts the lowering cam surface 25b of the centre cam 25 and the lowering cam surface 26a of the knitting cam 26B and moves down, but the slider butt 8 is held between the guide cam 28 and the slider guide cam 29B and moves substantially horizontally, during which time the needle 2 moves down while the end of the slider 7 does not move down. Therefore, the end of the slider comes closer to the hook 9 to close the hook 9. The needle butt 10 of the needle 2 lowered by the lowering cam surface 26a of the knitting cam 26B is at a full height since the presser 35B goes down, so that the select jack butt 10 is not pressed. The needle butt 10 is lowered to the lowermost end 44 of the knitting cam to pull the yarn previously fed and to produce fabrics having the standard density. When the needle butt 10 is lowered by the lowering cam surface 26a of the knitting cam 26B, the presser 35B is actuated to force the select jack butt 11 into the half-height position and to set the needle butt 10 of the needle 2 to the half-height position through the select jack 3. The needle butt 10 of the needle 2 which has received the yarn and has been moved down along the lowering cam surface 26a of the knitting cam 26 arrives near the lowermost end 44 of the knitting cam 26B. The needle butt 10 passes through the shoulder 43 at the half-height position so that the amount the needle 2 is lowered becomes less than that at the time of knitting ordinary stitches. Therefore, stitches knitted by the needle 2 are somewhat small. Whether the standard stitches or small stitches are chosen according to the passage through the lowermost end 44 or the shoulder 43 of the knitting cam 26B, it is to be noted that the knitting cam 26 itself may be moved up and down in the following manner. That is, in the course in which the carriage runs in the direction as indicated by the arrow, it is necessary that the leading knitting cam 26A is raised whereas the following knitting cam 26B is lowered. The stitch cam control device 50 of the knitting cam 26B in which the stitch cam control cam 59 has moved up to the uppermost position until termination of the knitting in the previous course and has rotated to the position at which the projecting portion 70 is opposite the proximity sensor 69 should cause the knitting cam 26B to be lowered to a predetermined density position. The angle of rotation of the knitting cam control motor 56 determines the lowering position by suitably inputting the number of pulses during the rotation of the motor according to the position thereof. The knitting cam control cam 59 which has most rotated in the stitch cam control device 50 shown in Fig. 3 and has been rotated by the rotation of the knitting cam control motor 56 into the state where the knitting cam 26B has been lowered to the lowermost position causes the extreme end of the stitch cam control lever 60 to be lowered, through the cam follower 61 fitted into the cam groove 58 of the cam 59, to lower the cam follower 67 which is engaged with the bent portion 66 at the extreme end thereof to determine the lowering position of the knitting cam 26B. In knitting the tack stitches, the select jack butt 11 is set to the position II. When the carriage advances as indicated by the arrow, the select butt 11 of the selector 4 and the needle butt 10 of the needle 2 move along the lines II and II′ respectively. At this time, the pressers 36A and 36B go down, whereas the presser 37 projects. The needle butt 10 comes into contact with and moves along the lifting cam surface 24a of the lifting cam 24, but when the needle butt 10 reaches the portion 24b of the shoulder of the lifting cam 24, the select jack butt 11 is pushed in by the projecting presser 37 and therefore the needle butt 10 does not come to the top of the lifting cam 24 and moves crossing thereover. At this time, the slider butt 8 moves horizontally until it passes through the straight line edge 29a of the slider guide cam 29A similarly to the needle which moves up to the aforesaid knit position. Therefore, the hook 9 is moved away from the extreme end of the slider 7 due to the upward movement of the needle butt 10 of the needle body 6, thereby to open the hook 9. However, the needle butt 10 does not come to the top of the lifting cam but moves crossing thereover as mentioned above, and therefore the slider butt 8 is also not moved upwards any further but passes through under the slider guide cam 27 while the hook 9 remains opened, and is lowered by the lowering cam surface 29b of the slider guide cam 29B, after which the slider butt 8 moves horizontally. The needle butt 10 which has crossed the top of the lifting cam 24 moves down along the lowering inclined surface 25b of the centre cam 25 and the lowering inclined surface 26a of the knitting cam 26 and runs taking the same course as the needle 2 which has moved up to the knit position and been lowered to the lowermost end of the knitting cam 26 to knit tack stitches having the standard density. On the other hand, when the presser 36B is projecting with respect to the needle 2 which has not moved up to the top of the lifting cam 24 by the action of the presser 37 but has moved up to the shoulder portion 24b (tack position) to receive a yarn and has started to be lowered by the centre cam 25, the needle butt 10 goes down at that position to be disengaged from the lowering inclined surface 26a of the knitting cam 26 so that at that position the needle butt 10 jumps the lowering inclined surface 26a of the knitting cam 26 and moves horizontally. When the select jack butt 11 is released from being pressed by the presser 36B, the needle butt 10 again projects and enters the course 46 between the knitting cam 26 and the projecting portion 45 of the fixed guide cam 34 and comes into contact with the lowering inclined surface 45a of the fixed guide cam 34 so that the needle butt 10 is lowered to the lowermost end. During that period, the slider butt 8 passes horizontally along the lower edge of the straight line edge 29a of the slider guide cam 29B to feed a yarn to the hook 9, but the needle butt 10 comes into contact with the lowering inclined surface 45a of the fixed guide cam 34 so that the hook 9, due to the lowering of the needle body 6 and due to the movement of the slider butt 8 towards the extreme end, is closed during the movement to the lowermost end. When the hook 9 is closed, the slider 7 moves along the line II′ without reckless movement due to the friction between the slider side and the needle groove wall. The knitting yarn to be fed is pulled to form a loop when the needle butt 10 moves down along the lowering guide surface 45a of the projecting portion 45 of the fixed guide cam 34. Since the position of the lowermost position of the projecting portion 45 of the fixed guide cam 34 is higher than the lowermost end 44 of the knitting cam 26B, the pull-in amount of the yarn is less than that and, accordingly, tack stitches which are small in density are knitted. When the welt position in which the needle 2 is not moved upwards at all is employed, the select jack butt 11 is set to the position III of the presser 38. When the presser 38 is projected to move the carriage, the select jack butt 11 is forced in by the presser 38 and accordingly the needle butt 10 also goes into the needle groove, as a consequence of which the needle butt 11 and the slider butt 8 do not come into contact with any cam of the cam lock 1 but they pass through the positions III′ and III″ respectively, and the needle 2 fails to act at all. While in the foregoing, a description has been given in which position I is the knit position, position II is the tack position, and position III is the welt position, it is to be noted that even in position II the needle can be raised to the knit position unless the presser 37 is activated, and when knit stitches having the standard size and knit stitches which are smaller than standard are prepared, the knit stitches of the standard size and the knit stitches smaller than standard select needles at the position II and position I respectively, so that the presser 35B acts similarly to that as described previously to cause it to pass through the shoulder 43 of the knitting cam 26. As described above, by using the knit run cam according to the present invention, knit stitches and tack stitches of standard size, and knit stitches and tack stitches of smaller than the standard size can be knitted by suitably selecting the needles. With the knit run cam according to the present invention as described above, four kinds of stitches, i.e. knit stitches of the standard size, knit stitches smaller than standard, tack stitches of standard size, and knit stitches smaller than the former, can be mixed in the same course, by a suitable needle being suitably selected for the respective knitting position. Moreover, the cam for lowering knitting needles different in the yarn lowering amount and the cam for lowering the tack needle can overlap the range for lowering the respective needles in the knitting width direction, and therefore the range of the provision of the stitch presser bar that has to be provided in the range in which the needle for knitting fabrics lowers to the resting position can be decreased, thereby to eliminate that cause of trouble. Furthermore, in the present invention, the needle lowering number can be decreased, and therefore the load when the needle is lowered can be reduced. Furthermore, since the cam for knitting tack stitches can easily shorten the yarn lowering length (density) as compared with the length for the knitting cam, the tack stitches can be made dense, and if this apparatus is utilised for a portion in the state where a loop is formed in the boundary of patterns of pattern fabrics or the like, fabrics in which the boundary of patterns is dense can also be obtained.

Claims: A knit run cam system comprising: a knitting needle (2) having a needle butt (10), a knitting cam (26B) having a needle butt lowering inclined face (26a) and a lowermost end (44), wherein the needle butt (10) of the knitting needle engages the needle butt lowering inclined face (26a) and the lowermost end (44) to form knit and tack stitches, and wherein said knitting cam (26B) has a recess (41), and a fixed guide cam (34) having a needle butt lowering inclined face (45a) and a lowermost end extension (45) for engagement with the needle butt (10) of the knitting needle to form tack stitches of decreased density, wherein the needle butt lowering inclined face (45a) and the lowermost end extension (45) of said fixed guide cam overlap the recess (41) in said knitting cam (26B) such that the lowermost end extension (45) of said fixed guide cam (34) is spaced from the lowermost end (44) of said knitting cam (26B). A knit run cam system as claimed in claim 1, characterised in that the lowermost end (44) of said knitting cam (26B) has a stepped portion (43) for engagement with the needle butt (10) to form knit stitches of decreased density. A knit run cam system as claimed in claim 1 or 2, characterised in that the recess (41) is formed at a central portion of the knitting cam (26B). A knit run cam system as claimed in claim 1, 2 or 3, further characterised by: a cam plate (21) having an oblique slot (51) therein, a stitch cam control having a sliding member (52) slidably received in the slot (51) in said cam plate (21) and connected to said knitting cam (26B) for moving said knitting cam (26B) obliquely on said cam plate (21), a stitch cam control motor (56) having a motor shaft (57) mounted on an upper surface of said cam plate (21), a stitch cam control cam (59) having a spiral cam groove (58) mounted on the motor shaft (57), a first cam follower (61) comprising a stitch cam control lever (60) received in the spiral cam groove (58), a second cam follower (67), and means (64) for engaging the stitch cam control lever (60) with the sliding member (52) through said second cam follower (67).

Inventors: SHIMA MASAHIRO, SHIMA, MASAHIRO
Applicants: SHIMA SEIKI MFG, SHIMA SEIKI MFG., LTD.
Application year: 1991
Main classification: D04B15
IPC codes: D04B15