Circular knitting machine

Abstract: A circular knitting machine, especially for manufacturing hosiery, provided with latch needles (4') which are mounted in a needle cylinder (1) and which are, in operation, lowered and lifted by swinging sinkers (4) provided each with two guiding butts (41, 42) which are alternately engageable with cam channels and which can be provided either on the needles (4') or on needle guiding sinkers (3), wherein for the rotational knitting direction (S) there is provided in the cam channel of the first guiding butts (41) at least one first sinking cam (10) while in the cam channel of the second guiding butts (42) there is provided at least one second sinking cam (11), or at least one third sinking cam (12) for the reverse knitting direction (S'). In the cam channel for the second guiding butts (42) there are provided cam means for transferring needles (4') from their knitting paths into the elevated heel path and vice versa, said means comprising three shaped through-grooves (71, 72, 73) provided at their ends with chamferings (711, 722, 733) for forcing the second guiding butts (42) into vertical tricks (2) in the needle cylinder (1). Above the starting point of each shaped through-groove (71, 72, 73) there is provided a swinging push-button (20, 21, 22), and in the cam channel of the first guiding butts (41) there are provided means for reducing and adding needles (4'). Said means, designed for reverse knitting operations, comprises a shaped through-groove (14') at the end of which there is provided a chamfering (141') for forcing the first guiding butts (41) into the vertical tricks (2) in the needle cylinder (1) while above the starting point of said groove (14') a radially reciprocating push-button (19') is arranged.

Description: The invention relates to circular knitting machines, especially machines for manufacturing hosiery or the like, provided with latch needles mounted in a needle cylinder. In operation, the needles are lowered and lifted by means of swinging sinkers which are provided with two guiding butts alternately engageable with cam channels. Alternatively, the butts can be provided immediately on the needles, or on guiding sinkers of double-head needles. Circular knitting machines provided with above-mentioned swinging sinkers having each two guiding butts, are well known for instance from EP-A-0 074 931. Such machines are adapted for reverse knitting operations, such as knitting heels and toes of hosiery, and particularly in a single feed system. The system is usually provided with a right-hand and lefthand sinking cam as well as with a heel cam the latter being designed for displacing the needles to the level of the above-mentioned sinking cams, i.e. in both knitting directions. Due to such an arrangement, the cam channels for butts of needles or of needle guiding sinkers cross each other. Below the heel cam there is provided a compensating cam which is designed for preventing the needles from assuming, owing to the knitting speed, a position which is lower than that which is suitable for laying thread into the needles. Consequently, the needle races are broken, and the guiding butts are exposed, during their motion, to many shocks so that their paths lose the curvilinear course. Apart from this, this motion, especially with double-cylinder machines, is ensured, within a race section, by upper butts while within another race section, by lower butts of guiding sinkers so that even the race continuity is impaired. In this case any increase of knitting speed is therefore difficult. It is an object of the present invention to eliminate the drawbacks of prior art as hereinabove referred to and to provide an improved circular knitting machine, especially for manufacturing hosiery, provided with latch needles which are mounted in the lower needle cylinder and which, in operation, are lowered and lifted by swinging sinkers provided with two guiding butts which are alternately engageable with cam channels and which can be provided either directly on the needles, or on the swinging sinkers received in vertical tricks of the lower needle cylinder. According to the invention, at least one first sinking cam, for the rotational knitting direction, is provided in the cam channel for first guiding butts while in the cam channel for second guiding butts there is provided at least one second sinking cam or at least one third sinking cam for the reverse knitting direction. Cam means are provided in the cam channel of the second guiding butts for transferring needles from knitting paths into an elevated heel path and vice versa, said means comprising especially three shaped through-grooves having at their ends chamferings for forcing the second guiding butts into vertical tricks of the needle cylinder. Above the starting point of each shaped through-groove is provided a swinging push-button while in the cam channel for the first guiding butts are provided means for reducing and adding needles in case of the reverse knitting operation, said means comprising especially a shaped through-groove having at its end a chamfering for forcing the first guiding butts into the vertical tricks of the needle cylinder, a radially movable push-button being provided above the starting point of said shaped through-groove. The cam channels for guiding the first and the second guiding butts are separate from each other for the two knitting directions. In order that the present invention be better understood and carried into practice, some preferred embodiments thereof will hereinafter be described with reference to the accompanying diagrammatic drawings, wherein: Figure 1 shows a lower needle cylinder together with guiding butts and swinging butts; Figure 2 is a sectional view of the cam block, indicating the co-operation of the swinging sinker together with the push-button; and Figure 3 is a detail showing the swinging push-button for reducing (narrowing) or adding, respectively. As can be seen in the drawings, a double-cylinder circular knitting machine designed for manufacturing ribbed goods and links-links hosiery, comprises an upper needle cylinder (not shown) and a lower needle cylinder 1. Vertical tricks 2 of said lower needle cylinder 1 receive guiding sinkers 3 of needles 4'. The needles 4' are of a double-head latch type which allows transfer to the upper needle cylinder for knitting links-links stitches. By means of a joint 31, each guiding sinker 3 carries a swinging sinker 4 having one first and one second guiding butt 41 and 42, respectively, as well as pattern butts 43. The cam system of the lower needle cylinder 1 comprises five cam sections 5, 6, 7, 8 and 9. In the cam section 6 is mounted for vertical motion a first sinking cam 10 for engaging the needle 4' in the rotational knitting direction S. In the cam section 8 a second vertically movable sinking cam 11 is provided for engaging the needles 4' in the rotational knitting direction S. Finally, in the cam section 9 there is disposed a third sinking cam 12 for engaging the needles 4' in the reverse knitting direction S'. The cam sections 5 and 6, if assembled together, form a channel 13 for the first guiding butts 41 of the swinging sinkers 4, the channel 13 constituting the work race for the needles 4' of the first knitting system for forming stitches in the rotational knitting direction S. A shaped through-groove 14' serves for guiding the first guiding butts 41 in the reverse knitting direction S' and terminates in a chamfering 141' for forcing the first guiding butts 41 into the vertical tricks 2 of the lower needle cylinder 1. In the cam section 7 are provided three shaped through-grooves 71, 72 and 73, and particularly in the path of the second guiding butts 42. The groove 71 is designed for transferring the needles 4' from the knitting position into the heel position during the reverse direction S' of rotation. The starting point of the groove 71 corresponds to the clearing position of the needle 4', and the end portion to the heel position. At its end the groove 71 has a chamfering 711 for forcing the second guiding butts 42 into the vertical tricks 2 of the needle cylinder 1. The shaped through-groove 72 serves for transferring the needles 4' from the heel position back to the knitting one during the reverse knitting direction S', the starting point of the groove 72 corresponding to the heel position of the needle 4' and the end portion to the clearing position. The end portion of the groove 72 has also a chamfering 722 for forcing the second guiding butts 42. Finally, the third shaped through-groove 73 is a mirror image of the groove 72 and serves for the same purpose. At the end of said groove 73 there is also a chamfering 733 for forcing the second guiding butts 42. The cam sections 8, 9 and 7 form in common a channel 15 for guiding the second guiding butts 42 to a height corresponding to that for guiding empty guiding sinkers 3 when their points open the latches of upper needles 4'; alternatively, said channel 15 can serve for transferring the needles 4' between the two needle cylinders. The cam sections 8 and 9 form a channel 16 within the path of the second guiding butts 42 for the stitch-forming motion of needles 4' in the second knitting system during the rotational knitting direction S, one part of said channel 16 being provided still in the cam section 9. In the cam section 9 is formed a shaped through-groove 91 which is a mirror image of the groove 71, including chamfering 911 of the groove 91, so that the latter serves for reducing the needle number for the rotational knitting direction S. Further in the cam section 9 there is formed, within the path of the second guiding butts 42, a shaped through-groove 92 giving the needles 4' the stitch-forming motion in the reverse knitting direction S' and partially also in the rotational knitting direction S, the groove 92 terminating at its ends in chamferings 921 and 922 designed for forcing the second guiding butts 42. In the transfer point there is provided in the cam section 9 a through-groove for a push-button 17. In the choice point V of needles 4' (indicated by dot-and-dash line) there is provided in the cam section 7 a vertical groove 18 designed for being engaged by swinging levers of well-known selecting means (not shown), which levers, in inoperative positions, enter the space between the pattern butts 43 while in operative positions they engage the paths of the butts 43. Upstream of the choice point V there is provided in the path of the first butts 41 a radially movable push-button 19 which enters, in operative position, the channel 14. Above the starting point of the channel 16 there is further provided within the path of the first guiding butts 41 in the channel 14 a radially movable push-button 19'. Above the starting points of said shaped through-grooves there are provided, at the height of the channel 13 or the channel 14, respectively, four swinging push-buttons 20, 21, 22, 23. Each of said push-buttons 20, 21, 22 and 23 comprises a swinging presser lever 24 (Figure 3) spring-loaded by a torsion spring provided about its pivot. The swinging presser level 24 is arranged on a carrier 25 fixedly supporting a permanent magnet 26 together with a coil 27 connected to a machine controlling computer. The carrier 25 can be approached to the lower needle cylinder 1. In operation, during the rotational knitting, the swinging push-buttons 20 to 23 are situated within the path of the second guiding butts 42 in the channel 14 so that they engage the guiding butts 41 in front of the choice point V. The guiding levers of the guiding means exert, according to a programme, a pressure to the pattern butts 43 so that the swinging sinkers 4 follow by their first guiding butts 41 the path of the channel 14 so that the guiding sinkers 3 and the corresponding needles 4' form then, in the first knitting system or on the first sinking cam 10, respectively, face stitches of the fabric . By the radially movable or approaching push-button 19' the first guiding butts 41 are forced into the lower needle cylinder 1 while the second guiding butts 42 are swung into the channel 16, and said needles 4' form face stitches in the second knitting system or on the second sinking cam 11 whereupon the guiding sinkers 3 are displaced again to the position in front of the choice point V or of the radially movable push-button 19. The swinging sinkers 4 whose pattern butts 43 have not been forced into the needle cylinder 1, are guided, by means of their second guiding butts 42, in the channel 15. By the push-button 17, both empty and guiding sinkers 3 together with needles 4' are disengaged so that the needles 4' are transferred between the two needle cylinders, provided the needles in the upper needle cylinder are also brought into the transfer position. The empty guiding sinkers 3 pass then by means of the first guiding butts 41 through the channel 15 up the choice point V. The needles 4' once transferred onto the upper needle cylinder, form there back stitches. The heel or the toe of a hose is formed by the reverse motion of the needle cylinders in the following way: The needles 4' are separated in the lower needle cylinder into operating and inoperating ones; also the guiding sinkers 3 are separated in this way. By the selecting device all the pattern butts 43 are pressed in. The radially movable push-button 24' is brought to the lower needle cylinder 1 in that section only which corresponds to the heel-forming needles 4'. The radially movable push-button 24' will press in the first guiding butts 41 so that second guiding butts 42 get into the shaped through-groove 91 where they are raised by the latter and pressed in again by the chamfering 911 whereby the first guiding butts 41 are received by the channel 13, and the corresponding guiding sinkers 3 or needles 4', respectively, assume an elevated heel position with stitches on the needle stems below the needle latches. The other needles 4' knit in the first knitting regime or system while the radially movable or approaching pushbuttons 19 and 19' are removed from the lower needle cylinder 1 whereby the second knitting system is set out of operation. Meanwhile the machine is given the reverse motion, and the swinging push-buttons 20 and 21 are brought to the lower needle cylinder 1. The operating needles 4' are in the clearing position, which means that the first guiding butts 41 are in the channel 14 and, still before changing the rotational knitting direction S into the reverse knitting direction S', there is effected the first stitch reducing or narrowing phase by means of the swinging push-button 21 which can force only one first guiding butt 41. The swinging push-button 21 or 20, respectively, operates in such way that the first guiding butt 41, owing to friction, carries along the swinging presser lever 24 which swings into a space between the adjacent first guiding butt 41 so that the next first guiding butt 41 swings up to the zone of action of the permanent magnet 26 which will attract it whereas the further first guiding butts 41 are allowed to pass and are pressed-in in the further narrowing phases. In this phase the swinging presser lever 24 of the swinging push-button 20 is held by the permanent magnet 26. By pressing the first guiding butt 41 in, the corresponding second guiding butt 42 is pressed out into the shaped through-groove 91 while, during further rotation, it strikes the chamfering 911 whereby the first guiding butts 41 is tilted out backward but into the channel 13, i.e. to the inoperative height. Thus the corresponding guiding sinker 3 and the needle 4' are displaced into the heel-forming position. During this direction of rotation the swinging presser lever 24 of the swinging push-button 20 is held by the permanent magnet 26. If the rotational direction is changed to the reverse one S', the first guiding butts 41 are led through the channel 14 up to the shaped through-groove 14' where they are pressed in by the chamfering 141'. The second guiding butts 42 of the swinging sinkers 4 are tilted out into the shaped through-groove 92, and the corresponding needles 4' form stitches in the first knitting system in the reverse knitting direction S' on the third sinking cam 12. After the stitch formations the needles 4' are raised into the clearing position while the chamfering 921 will press in the second guiding butts 42 into the vertical tricks 2, and the first guiding butts 41 enter the channel 14. The group of operating needles 4' is then led by means of the channel 14 up to the dead point while before the latter the needle 4' or the guiding sinker 3, respectively, is eliminated from this group into the heel-forming position by the swinging push-button 20, and particularly in the same way as described with the swinging push-button 21, which means by the shaped through-groove 71 and the chamfering 711. A part of the first guiding butts 41 belonging to the corresponding operating needles 4', upstream of the dead point, is led again through the shaped through-groove 14' and is pressed in by the chamfering 141', and further on the guiding sinkers 3 are led up to the dead point by the second guiding butts 42 in the shaped through-groove 92. Downstream of the dead point, during the rotational knitting direction S, said second guiding butts 42 are pressed in by the chamfering 922, and the guiding sinkers 3 are led by means of the first guiding butts 41. When the coil 27 is supplied with current, the permanent magnet 26 releases the swinging presser lever 24 of the swinging push-button 21 which, due to the force of a torsion spring, reassumes its initial position whereupon the next removal of the needle 4' can be effected as hereinbefore described. When the reduction of the predetermined number of needles 4' is ended, the knitting of the second heel portion is effected in the following way while the heel-forming needles 4' are being added again. The swinging push-buttons 22 and 23 are set in operation; these, however, are shaped so that their swinging presser levers have a larger working front whereby they gradually press in the two first guiding butts 41. Otherwise their function remains the same. These swinging butts 22 and 23 alternately press in the first guiding butts 41 from both sides of the group of swinging sinkers 4 belonging to the guiding sinkers 3 or to the needles 4', respectively, in the elevated heel-forming position. In this way the second guiding butts 42 are tilted out into the shaped through-grooves 72 or 73, respectively, and are pressed in again by the chamferings 722 and 733 so that their first guiding butts 41 are tilted out again into the channel 14, and the needles 4' are transferred in this way back to the knitting position. Simultaneously, however, the swinging push-buttons 20 and 21 are in operation, which results again in adding only one needle 4' in each of the two knitting directions. After the needle adding has been ended, said swinging push-buttons 20 to 23 are displaced away from the lower needle cylinder 1, and the knitting machine continues its rotational operation as explained above. Within the scope of the present invention it is possible to provide the swinging sinkers 4 immediately on the needle stems in case of the single-cylinder knitting machines manufacturing hosiery with reverse heel or toe, respectively, or with single-cylinder machines for creating the so-called intarsia designs on calf by means of reverse knitting, without affecting the subject-matter of the invention. It will be understood that the invention can be applied to a machine with a plurality of knitting systems operating either in the reverse or rotational regime. The sinking cams of the knitting systems in the rotational operation can be provided only within the path of one type of guiding butts, which is preferable with single-cylinder machines, or in the paths of both guiding butt types, depending upon the possibilities of other knitting technologies applicable on the machine. However, for the reverse operation the conditions it holds that the sinking cams for the rotational and the reverse direction of knitting S and S', respectively, are always disposed in the grooves of the first and the second guiding butts 41 and 42, respectively. Further, in lieu of the swinging push-buttons, it is possible to use only radially movable push-buttons or any other means for pressing in the corresponding guiding butts but with the machine only, wherein, in lieu of the well-known reverse mechanism, there is used a well-known electric motor with reverse rotation; in this case the swing extent can be controlled by means of a micro computer. Such means for pressing in the guiding butts would be, in the reverse regime, fixedly attached whereas the butts would be approached by said electric motor. For controlling the guiding butts it is also possible to use stationary cam means instead of shaped through-grooves 71 to 73 and 92, including the corresponding chamferings for pressing them in, the independence of said means being maintained, which means that the paths of the butts are separate from one another.

Claims: A circular knitting machine, especially for manufacturing hosiery, provided with latch needles (4') which are mounted in a lower needle cylinder (1) and which are lowered and lifted by swinging sinkers (4) provided each with two guiding butts (41, 42) which are alternately engageable with cam channels and which can be provided either directly on the needles (4'), or on guiding sinkers (3) received in vertical tricks (2) of the lower needle cylinder (1), the machine being characterised in that for the rotational knitting direction (S) there is provided in the cam channel for first guiding butts (41) of the swinging sinkers (4) at least one first sinking cam (10) while in the cam channel of second guiding butts (42) there is provided at least one second sinking cam (11) or at least one third sinking cam (12) for the reverse knitting direction (S'). A circular knitting machine according to Claim 1, characterised in that in the cam channel of the second guiding butts (42) there are provided cam means for transferring needles (4') from their knitting paths into an elevated heel path and vice versa, said means comprising three shaped through-grooves (71, 72, 73) having at their ends chamferings (711, 722, 733) for forcing the guiding butts (42) into the vertical tricks (2) of the lower needle cylinder (1) while above the starting point of each of the shaped through-grooves (71, 72, 73) there is provided a swinging push-button (20, 21, 22), and in the cam channel for the first guiding butts (41) there are provided means for reducing and adding needles (4') during the reverse knitting operation, said means comprising a shaped through-groove (14') at the end of which there is provided a chamfering (141') for forcing the first guiding butts (41) into the vertical tricks (2) of the lower needle cylinder (1), a radially movable push-button (19') being disposed above the starting point of the shaped through-groove (14'). A circular knitting machine according to Claim 1 or 2, characterised in that the cam channels for guiding said first guiding butts (41) and said second guiding butts (42) are for the two knitting directions separate from each other.

Inventors: FUCIK MILAN, FUCIK, MILAN
Applicants: UNIPLET AS, UNIPLET A.S.
Application year: 1992
Main classification: D04B15
IPC codes: D04B15, D04B9