EP3956505B1

EP3956505B1 - A circular knitting machine and method for manufacturing an open-work knitted fabric

Info

Publication number: EP3956505B1
Application number: EP20718395.5A
Authority: EP
Inventors: Maurizio LODRINI; Mauro ALGHISI
Original assignee: Santoni SpA
Current assignee: Santoni SpA
Priority date: 2019-04-16
Filing date: 2020-04-10
Publication date: 2024-05-08
Anticipated expiration: 2040-04-10
Also published as: CN111826786A; EP3956505A1; TW202104701A; IT201900005900A1; WO2020212818A1

Description

Field of the invention

The present invention relates to a method for manufacturing an open-work knitted fabric on a circular knitting machine, and to a circular knitting machine configured for implementing said method.
In particular, the present invention relates to the sequence of movements for the mechanisms (needles and sinkers) of the circular knitting machine designed to manufacture an open-work knitted fabric.
For instance, the present invention relates to circular knitting machines configured for manufacturing fabrics with intarsia motifs (intarsia machines or argyle machines), which are also able to manufacture open-work knitted fabrics.

Background of the invention

As is known, circular knitting machines comprise a needle-holding element (needle cylinder and/or plate) on which one or more series of needles are arranged along a circular path (circular needlebeds), and devices apt to control the movement of the needles for knitted fabric formation. Knockover sinkers are arranged in radial seats obtained in a ring-shaped body (sinker crown) arranged around the needle-holding cylinder, and said sinkers cooperate with the needles so as to make knitted fabric.
While executing particular designs with circular knitting machines, it is known to manufacture open-work knitted fabrics.
Document GB449404 discloses a circular knitting machine equipped with sinkers arranged between the needles and on which interstitch rings are formed. At least one of these sinkers comprises a protruding lateral portion, which is configured for moving an interstitch ring onto an adjacent needle so as to create an opening in the knitted fabric.
Document GB377794 discloses a circular knitting machine equipped with a spreader provided with a pair of blades placed on opposed sides of a sinker and configured for spreading an interstitch and arranging it on one or both adjacent needles.
Document GB410831 discloses a circular knitting machine comprising some sinkers provided with an upper hook or with a pair of hooks placed on the sides of a traditional sinker. Said hooks are configured and moved so as to displace an interstitch on a pair of adjacent needles and make an open work in the fabric. A selector moves the sinker with the hook integrated therein when said hook must work. The selector comprises an oscillating arm provided with butts interacting with a plurality of cams belonging to an actuating device.
A circular knitting machine configured for manufacturing fabrics with intarsia motifs (intarsia machine) is disclosed for instance in document EP1620590 issued to the same Applicant.
Intarsia is a knitting technique enabling to obtain motifs using yarns of different colors in the same knitted course. Intarsia technique is usually used for creating multicolored motifs. As for woodworking technique, which it shares the name with, fields with different colors and materials seem to be fitted together as in a puzzle. Differently from other multicolor knitting techniques, there is only "active" color on a given stitch and the yarn is not moved to the reverse. When a color changes on a given row/knitted course, the old yarn is left hanging.
Document FR1427471A discloses a circular knitting machine and a corresponding process for producing open-work knitted fabric using, in combination, conventional sinkers and open-work sinkers having a nose which is offset relative to the planar extension of the main body of the sinker itself. In such machine, the conventional sinkers and the open-work sinkers follow separated paths which are defined on a fixed guiding ring. On one hand, the conventional sinkers follow a predetermined path on the guiding ring and therefore they have a unique trajectory constant over time. On the other hand, for the open-work sinkers, the guiding ring is provided with at least two different paths defining an inner trajectory and an outer trajectory. The transfer of the open-work sinkers from one trajectory to the other is determined by the activation of specific cams or actuators operatively active on the guiding paths.
Document US6286343B1 shows a device for the selection of the sinkers for the manufacture of designed terry cloth knitwear on circular knitting machines and stocking knitting machines. Each sinker of the device of US6286343B1 is capable of oscillations in a vertical plane between a canceled, resting position, in which its tail end is not intercepted by a return cam, and an operating position, in which its tail end interacts with the return cam for the longitudinal movements of the sinker.
Document FR2249198A1 discloses a circular knitting machine wherein hosiery is produced using multiple yarn supply stations disposed symmetrically about the needle cylinder.
Document WO2018/197971A1 describes a circular knitting machine comprises a needle-holding cylinder housing a plurality of needles, at least one yarn feed, actuating cams movable with respect to the needle-holding cylinder, a drive chain for each needle operatively placed between the respective needle and the actuating cams.
Document EP1524348A1 discloses a sinker selection device in a circular knitting machine, comprising for each radial slot of the sinker ring in which sinkers are accommodated, a selector facing the end of the corresponding radial slot directed away from the axis of the sinker ring. The selector is oscillatable on a radial plane with respect to the sinker ring to pass from active to inactive positions to induce different actuation of the corresponding sinker along the corresponding radial slot. A selection actuator is provided which laterally faces the sinker ring and can engage on command the selector for transfer from inactive to active positions. Document EP0147139A2 shows a jacquard circular knitting machine provided with a needle cylinder driving mechanism capable of optionally and readily controlling the rotary motion of the needle cylinder according to the pattern to be knitted.

Summary

In the framework of circular knitting machines as the ones disclosed above, the Applicant has identified the presence of some drawbacks.
First of all, the Applicant has observed that the above described known machines for manufacturing an open-work knitted fabric and the methods for manufacturing an open-work knitted fabric which known machines can implement, do not allow to manufacture complex fabrics with open-work areas differing from one another.
In particular, the Applicant has observed that some of said known machines are not able to individually select the elements designed to make an open work, since these elements are guided by cams and necessarily make all the same movements during each turn of the machines. As a result, the number, arrangement and other features of the open work to be made are preset and hard to change.
The Applicant has further observed that said known machines are not able to manufacture fabrics with open-work areas in a rapid and flexible manner.
Under these circumstances, an aim underlying the present invention, in its various aspects and/or embodiments, is to propose a method for manufacturing open-work knitted fabrics and a circular knitting machine enabling to manufacture open-work knitted fabrics with the most different features.
A further aim of the present invention is to propose a method for manufacturing open-work knitted fabric and a circular knitting machine which is able to manufacture open-work knitted fabrics, which are so flexible as to manufacture different fabrics as a function of the features of the open work to be obtained on the fabric.
A further aim of the present invention is to provide a method for manufacturing open-work knitted fabric and a circular knitting machine which is able to manufacture highly complex open-work knitted fabrics in relatively short manufacturing times.
A further aim of the present invention is to provide a method for manufacturing open-work knitted fabric and a circular knitting machine which is able to manufacture open-work knitted fabrics, enabling also to obtain further motifs and/or effects on the knitted fabric, for instance without having to reconfigure the machine itself or parts of it from a mechanical point of view.
A further aim of the present invention is to provide a circular knitting machine configured for manufacturing fabrics with intarsia motifs (intarsia machine or argyle machine), which is also able to manufacture open-work knitted fabrics according to the aims listed above.
These and other possible aims, which shall appear better from the following description, are basically achieved by a method for manufacturing open-work knitted fabric and by a circular knitting machine for manufacturing open-work knitted fabric according to one or more of the appended claims and according to the following aspects and/or embodiments, variously combined, possibly also with the aforesaid claims.
In the present description and in the appended claims, the words "upper", "lower", "above" and "below" relate to the positioning of the machine during normal operation with the central axis of rotation in vertical position and the cylinder needles with their heads pointing upwards.
In the present description and in the appended claims, the words "axial", "circumferential", "radial" relate to said central axis.
In the present description and in the appended claims, the words "non-operating", "withdrawn" and "dropped" relate to respective positions and functions of the needles. In particular, in the non-operating position the needles are in a fully lowered or retracted position in the needle-holding cylinder, such as not to pick the yarn supplied on the feed forming the loop. In the withdrawn position, the needles are in a raised position with respect to the non-operating position, such as to pick the textile yarn supplied by the yarn feed without dropping the knitted loop lying inside its needle head. In the dropped position, the needles are in a fully raised position, such as to pick the textile yarn supplied by the yarn feed dropping the knitted loop lying on its stem.
Some aspects of the invention are listed below.
In one aspect, the invention relates to a circular knitting machine.
The circular knitting machine comprises:

a needle-holding cylinder and a circular crown having a common central axis;
a plurality of needles installed on the needle-holding cylinder, movable along a longitudinal development thereof and each having a head arranged around the central axis so as to define a circular needlebed;
a plurality of knockover sinkers installed in the circular crown, movable along radial directions with respect to said central axis and each having a pin configured for cooperating with the needles so as to make a knitted fabric;
a plurality of open-work sinkers installed in the circular crown, placed beside the knockover sinkers, movable along radial directions with respect to said central axis and each having a protrusion configured for cooperating with the needles so as to make an open-work knitted fabric;
at least one yarn feed operatively associated to a respective group of needles, to a respective group of knockover sinkers and to a respective group of open-work sinkers so as to feed at least one textile yarn to the circular needlebed;
wherein the needle-holding cylinder and the circular crown are rotatable around the central axis with respect to the yarn feed.

In one aspect, the machine is configured for manufacturing an open-work knitted fabric and/or for implementing a method for manufacturing open-work knitted fabric.
The method comprises or the machine is configured for:

i. rotating the needle-holding cylinder and the circular crown around the central axis and radially moving selected open-work sinkers of said group of open-work sinkers towards the central axis and towards a respective forward position; lifting and then lowering the needles of said group of needles beside the selected open-work sinkers placed in the forward position, while the needle-holding cylinder and the circular crown rotate and pass over said at least one yarn feed so as to load the textile yarn fed by said yarn feed onto the protrusions of the selected open-work sinkers so as to make elongated interstitches;
ii. rotating the needle-holding cylinder and the circular crown around the central axis and radially moving the selected open-work sinkers away from the central axis, towards a respective backward position, lifting the needles at least in a withdrawn and/or unloaded position, so as to unload the interstitch on the protrusions within the heads of the needles, and continuing rotating the needle-holding cylinder and the circular crown until said at least one yarn feed is passed over and then lowering the needles while the selected open-work sinkers are in the respective backward position;

In other words, while the needle-holding cylinder and the circular crown rotate with an alternating rotary motion, the textile yarn is fed one or more times on the protrusions of the open-work sinkers selected for making elongated interstitches and then said interstitches lying on the protrusions are dropped into the needle heads. The Applicant has found out that the invention enables to solve the problems listed above related to the prior art and thus to obtain the intended aims.
The Applicant has first found out that the invention enables to manufacture highly complex open-work knitted fabrics in relatively short times by working so as to make the interstitch by means of an alternating motion of the machine.
The Applicant has further found out that the invention enables to manufacture open-work knitted fabrics of various types and with the most different features by means of a specific selection of the open-work sinkers required for making the open work to be manufactured.
As a matter of fact, the Applicant has found out that the machine according to the invention is highly flexible since it allows to switch from manufacturing a type of knitted fabric to a different type in a fast and relatively simple manner.
Further aspects of the invention are listed below.
In one aspect, the circular knitting machine is an intarsia machine, i.e. a machine configured for manufacturing fabrics with intarsia motifs (intarsia machine or argyle machine).
In one aspect, the circular knitting machine is configured for working with alternating rotary motion.
In one aspect, the circular, e.g. intarsia, knitting machine comprises at least two yarn feeds, or at least four feeds, each one configured for working with a respective group of needles arranged along an arc of circle by means of an alternating rotary motion of the needles around the central axis.
In one aspect, said at least two yarn feeds cooperate to form every knitted course by rotating in both directions. In one aspect, at least one motor is operatively connected to the needle-holding cylinder and to the crown so as to make them rotate around the central axis.
In one aspect, cams and/or other types of devices are arranged around the needle-holding cylinder so as to turn the rotational motion of the needle-holding cylinder into an axial motion of the needles.
In one aspect, the machine comprises at least one selecting actuator laterally facing the circular needlebed, which can be engaged upon command, either directly or indirectly, with each of the open-work sinkers of said respective group of open-work sinkers.
In one aspect, the selected open-work sinkers are selected by means of said selecting actuator.
In one aspect, said at least one yarn feed is at a circumferential distance from the respective selecting actuator. In one aspect, the needle-holding cylinder and the circular crown are rotatable around the central axis with respect to the selecting actuator.
In one aspect, the machine comprises a plurality of selecting actuators, for instance each one placed on a yarn feed that is operatively associated to a different selecting actuator.
In one aspect, in order to make the open work, the yarn feed is angularly offset with respect to the respective selecting actuator of an angle, e.g. of 90° to 180°.
In one aspect, the group of knockover sinkers and the group of open-work sinkers operatively associated to a yarn feed and to a selecting actuator, have an angular extension, e.g. of 180° or less, e.g. of 90° or less, e.g. 45°.
In one aspect, the machine comprises four yarn feeds angularly offset one with respect to the other, i.e. of 90°, and four selecting actuators angularly offset one with respect to the other, e.g. of 90°, wherein each yarn feed, in order to make the open-work, is angularly offset with respect to the respective selecting actuator, e.g. of 90°. In one aspect, each yarn feed comprises a yarn feeder.
In one aspect, the yarn feeder is movable between an operating position and a rest position.
In one aspect, in the operating position the yarn feeder is located radially outside the needlebed so as to allow the needles to catch the textile yarn.
In one aspect, in the rest position the yarn feeder is located radially inside the needlebed so as to prevent the needles from catching the textile yarn.
In one aspect, an open-work sinker is arranged on one side of at least some of the knockover sinkers.
In one aspect, an open-work sinker contributes to make a respective interstitch loop.
In one aspect, a right open-work sinker and a left open-work sinker are arranged on opposed sides of at least some of the knockover sinkers, i.e. each of the knockover sinkers is flanked by a pair of open-work sinkers and each pair of open-work sinkers contributes to make an interstitch loop.
In one aspect, each open-work sinker or each pair of (right and left) open-work sinkers cooperates with a single needle or with a pair of adjacent needles so as to make a respective interstitch loop.
In one aspect, knockover sinkers provided with the right open-work sinker and with the left open-work sinker are alternated with single knockover sinkers, i.e. without the right open-work sinker and the left open-work sinker.
In one aspect, the open-work sinker has a respective protrusion that is laterally offset with respect to the respective knockover sinker.
In one aspect, the right open-work sinker and the left open-work sinker exhibit respective protrusions that are laterally offset towards opposed sides of the respective knockover sinker and for instance placed above the respective knockover sinker. In one aspect, the protrusions are configured for loading and stretching the interstitch and arrange it on a respective single needle or on two respective adjacent needles placed on opposed sides of the respective knockover sinker and form the open work. The use of two open-work sinkers for one knockover sinker allows to make wider, better defined open works, thus obtaining a balanced knitted fabric without twists or folds.
In one aspect, each knockover sinker provided with the open-work sinker, or with the right open-work sinker and with the left open-work sinker, is housed in a respective groove together with said open-work sinker, or with said right open-work sinker and left open-work sinker.
In one aspect, each knockover sinker provided with the open-work sinker, or with the right open-work sinker and with the left open-work sinker, is radially sliding in the respective groove and with respect to said open-work sinker.
In one aspect, the open-work sinker, or the right open-work sinker and the left open-work sinker, is/are radially sliding in the respective groove and with respect to the respective knockover sinker.
In one aspect, each single knockover sinker is housed in a respective groove so as to radially slide in said groove.
In one aspect, the selected open-work sinkers are selected by means of a selecting actuator laterally facing the circular needlebed, which can be engaged upon command, either directly or indirectly, with each of the open-work sinkers of said respective group of open-work sinkers.
In one aspect, step i. is executed in the first direction of rotation only, in which the textile yarn is loaded onto the protrusions of the selected open-work sinkers at least twice, so as to make a double interstitch, at least on a first yarn feed and on a second yarn feed placed one after the other.
In one aspect according to the preceding aspect, step ii. is executed in the second direction of rotation only, in which the double interstitch lying on the protrusions is dropped onto the second yarn feed.
According to the description in the two preceding aspects, while the needle-holding cylinder and the circular crown rotate in the first direction of rotation, the textile yarn is loaded onto the open-work sinkers on the first feed and is loaded again onto the same open-work sinkers on the second feed so as to make two elongated interstitches. Then, while the needle-holding cylinder and the circular crown rotate in the second direction of rotation, said two elongated interstitches are unloaded into the needle heads on the second feed.
In a different aspect, step i. is executed before, while the needle-holding cylinder and the circular crown rotate in the first direction of rotation and then in the second direction of rotation, in which the textile yarn is loaded onto the protrusions of the selected open-work sinkers at least twice, so as to make a double interstitch, on the same single yarn feed.
In one aspect according to the preceding aspect, step ii. is executed while the needle-holding cylinder and the circular crown rotate in the first direction of rotation, in which the double interstitch lying on the protrusions is dropped onto the protrusions on said single yarn feed.
According to the description in the two preceding aspects, the textile yarn is loaded onto the open-work sinkers on a feed while the needle-holding cylinder and the circular crown rotate in the first direction of rotation, and is loaded again onto the same open-work sinkers on the same feed while the needle-holding cylinder and the circular crown rotate in the second direction of rotation so as to make two elongated interstitches. Then, while the needle-holding cylinder and the circular crown rotate in the first direction of rotation, said two elongated interstitches are loaded into the needle heads on the same feed.
In one aspect, before step i. the method comprise (or the machine is configured for):

moving the group of needles, the group of knockover sinkers and the group of open-work sinkers upstream from the respective selecting actuator with respect to the first direction of rotation, wherein the open-work sinkers are in the backward position;
actuating the selecting actuator;
putting the needle-holding cylinder and the circular crown in rotation around the central axis and in said first direction of rotation so that at least some of the open-work sinkers of the group of open-work sinkers are selected and radially moved towards the central axis and towards the respective forward position.

In one aspect, in step ii., while the rotation goes on beyond said at least one yarn feed, the needles do not pick the textile yarn from said yarn feed. Therefore, the needles do not make any stitch by only contribute to the open-work.
In one aspect, a yarn feeder of said yarn feed is moved to a rest position so that the needles do not pick the textile yarn from said yarn feed.
In one aspect, in step ii., while the rotation goes on beyond said at least one yarn feed, the needles pick a further yarn so as to make a stitch cooperating with the knockover sinkers. In this variant, beyond contributing to the open-work, the needles also make a stitch.
In one aspect, a yarn feeder of said yarn feed remains in an operating position so that the needles pick the further textile yarn from said yarn feed.
In one aspect, step ii. comprises (or the machine is configured for):

radially moving the selected open-work sinkers away from the central axis in an intermediate position by keeping the needles in a non-operating position and/or in a position below the withdrawn position (i.e. in a position in which they do not pick the yarn);
lifting the needles at least in the withdrawn position, so that the protrusions of the selected open-work sinkers lies beside the heads of the needles;
further radially moving the selected open-work needles away from the central axis as far as said backward position, so as to unload the interstitches lying on the protrusions into the heads of the needles;
continuing rotation until the yarn feed is passed over without the needles picking up the textile yarn from the yarn feed, or so that the needles reach a dropped and/or withdrawn position and pick up a further yarn from the yarn feed so as to make a stitch in cooperation with the knockover sinkers;
lowering the needles while the selected open-work sinkers, after unloading the interstitch, are in the backward position.

In one aspect, the needle-holding cylinder and the circular crown rotate in the second direction of rotation until the group of needles, the group of knockover sinkers and the group of open-work sinkers are moved back upstream from the respective selecting actuator.
In one aspect, during steps i. and ii., all the open-work sinkers of said group of open-work sinkers are selected for manufacturing open-work knitted fabric.
According to a different aspect, during steps i. and ii., only some of the open-work sinkers of said group of open-work sinkers are selected for manufacturing portions of open-work knitted fabric.
In one aspect, radially moving the selected open-work sinkers away from the central axis in the intermediate position comprises: moving a transfer cam so as to catch and deviate butts of said selected open-work sinkers. In one aspect, further moving the selected open-work sinkers as far as said backward position comprises: moving an auxiliary transfer cam so as to catch and deviate butts of said selected open-work sinkers.
In one aspect, once the group of needles, the group of knockover sinkers and the group of open-work sinkers is moved back upstream from the respective selecting actuator, and if the needles do not pick the textile yarn from the yarn feed and do not make a stitch, the selecting actuator is kept in a non-operating position and the needle-holding cylinder and the circular crown are put in rotation in the first direction of rotation so that each of the open-work sinkers of the group of open-work sinkers remains in the backward position until the yarn feed is passed over and while the open-work sinkers remain in the backward position and the needles remain in the lowered position, so as to reset the operating sequence without making any stitch.
In one aspect, once the operating sequence without making any stitch is reset, the direction of rotation of the needle-holding cylinder and of the circular crown is reverted by lifting and then lowering the needles so as to make a stitch with the textile yarn fed by said yarn feed in cooperation with the knockover sinkers while the needle-holding cylinder and the circular crown rotate in the second direction of rotation until the group of needles, the group of knockover sinkers and the group of open-work sinkers are moved again upstream from the respective selecting actuator with respect to the first direction of rotation.
In one aspect, once the group of needles, the group of knockover sinkers and the group of open-work sinkers are moved back upwards of the respective selecting actuator, the method comprises:

keeping the selecting actuator in the non-operating configuration;
putting the needle-holding cylinder and the circular crown in rotation around the central axis and in the first direction of rotation while each of the open-work sinkers of the group of open-work sinkers remains in the backward position;
lifting and then lowering the needles so as to make a stitch with the textile yarn fed by said yarn feed in cooperation with the knockover sinkers while the needle-holding cylinder and the circular crown rotate in the first direction of rotation until said yarn feed is passed over;
reverting the direction of rotation of the needle-holding cylinder and the circular crown by lifting and then lowering the needles so as to make a stitch with the textile yarn fed by said yarn feed in cooperation with the knockover sinkers while the needle-holding cylinder and the circular crown rotate in the second direction of rotation until the group of needles, the group of knockover sinkers and the group of open-work sinkers are moved again upstream from the respective selecting actuator with respect to the first direction of rotation.

In one aspect, the machine comprises at least one guiding ring operatively associated to the crown, wherein the crown is rotatable with respect to the guiding ring and around the central axis.
In one aspect, each knockover sinker has a butt engaged with a first guide obtained in the guiding ring and developing around the central axis; wherein the first guide is configured for moving the knockover sinker radially along the respective radial groove when the crown rotates with respect to the guiding ring and around the central axis.
In one aspect, each open-work sinker has a butt that is or can be engaged with a second guide obtained in the guiding ring and developing around the central axis, wherein the second guide defines a plurality of trajectories for the open-work sinker, wherein the second guide is configured for moving the open-work sinker radially when the crown rotates with respect to the guiding ring and around the central axis.
In one aspect, the machine comprises a selector operatively coupled with each open-work sinker, wherein the selector is movable, e.g. oscillating, in a radial plane between a rest position and an operating position, wherein in the operating position the selector acts directly or indirectly upon the open-work sinker so as to deviate the butt of the open-work sinker along a trajectory of the second guide.
In one aspect, each knockover sinker has a nose configured for making terry stitches in cooperation with the needles.
In one aspect, the machine comprises a selector operatively coupled with each knockover sinker, wherein the selector is movable, e.g. oscillating, in a radial plane between a rest position and an operating position, wherein in the operating position the selector acts directly or indirectly upon the knockover sinker so as to deviate the butt of the knockover sinker along a trajectory of the first guide.
In one aspect, the selecting actuator laterally faces the crown, fixed with respect to the guiding ring, that can be engaged under control with the selectors and is configured for causing the selectors to switch from the rest position to the operating position.
In one aspect, the machine comprises a plurality of pushing units, each associated to a selector and to an open-work sinker or to a knockover sinker.
In one aspect, in the operating position the selector rests against the pushing unit and the pushing unit is configured for pushing against the open-work sinker or against the knockover sinker.
In one aspect, the guiding ring comprises a third guide extending around the central axis and defining a plurality of trajectories.
In one aspect, each pushing unit exhibits a butt that is or can be engaged with the third guide.
In one aspect, the guiding ring comprises a circular track extending around the central axis.
In one aspect, each selector, e.g. the base portion of each selector, is slidingly engaged into the circular track so as to rotate together with said at least one open-work sinker or knockover sinker.
Further characteristics and advantages shall be more evident from the detailed description of a preferred embodiment of a method for manufacturing open-work knitted fabric and of a circular knitting machine for manufacturing open-work knitted fabric according to the present invention.

Description of the drawings

This description shall be made below with reference to the accompanying drawings, provided to a merely indicative and therefore non-limiting purpose, in which:

Figure 1 shows a portion of a circular knitting machine according to the present invention with some parts removed for better showing others;
Figure 2 shows an exploded view of an assembly of elements belonging to the machine in Figure 1;
Figure 3 shows the assembly of Figure 2 with the elements associated to one another;
Figure 4 shows an exploded view of a different assembly of elements belonging to the machine in Figure 1;
Figure 5 shows the assembly of Figure 4 with the elements associated to one another;
Figure 6 shows a schematic plan view of a portion, including a guiding ring, of the machine as in the preceding figures;
Figures 7A to 30A schematically show a plan view of the machine as in the preceding figures, in which respective operating steps are pointed out in a schematic manner;
Figures 7B to 30B show a detailed portion of the machine as in the preceding figures, in the operating steps corresponding to those of Figures 7A to 30A.

Detailed description

With reference to the figures mentioned, the numeral 1 globally designates a portion of a knitting head of a circular knitting machine according to the present invention. The circular knitting machine shown is a machine configured for manufacturing fabrics with intarsia motifs (intarsia machine or argyle machine). The circular knitting machine comprises a basement, not shown since it is of known type, constituting the supporting structure of the machine, and said knitting head 1 is mounted onto the basement.
The knitting head 1 is equipped with a needle-holding cylinder 2, with a plurality of needles 3 mounted onto the needle-holding cylinder 2, and with control means, not shown, apt to selectively actuate the needles 3 so as to enable the production of a fabric. The needle-holding cylinder 2 is usually mounted in vertical position onto the basement, with the needles 3 arranged vertically and protruding beyond an upper edge of the needle-holding cylinder 2. The needles 3 have heads 3A arranged around the central axis "X-X" so as to define a circular needlebed.
As is known, the needle-holding cylinder 2 has a plurality of longitudinal grooves obtained on a radially outer surface of the needle-holding cylinder 2. The longitudinal grooves are arranged around a central axis "X-X" (vertical) of the needle-holding cylinder 2 and develop parallel to said central axis "X-X". Each longitudinal groove houses a respective needle 3 and a respective drive chain comprising a plurality of flat parts. Actuating cams are arranged as a casing around the needle-holding cylinder 2 and lie facing the radially outer surface of the cylinder 2 and thus the longitudinal grooves and the drive chains. These actuating cams are defined e.g. by plates and/or grooves arranged on an inner surface of the casing.
In one embodiment, the casing of the actuating cams is basically stationary, whereas the needle-holding cylinder 2 rotates (with a continuous or alternating motion in both directions) around the central axis "X-X" by means of a suitable motor, so as to generate a relative rotational motion between the drive chains and the actuating cams and turn the rotational motion of the needle-holding cylinder 2 into an axial motion of the needles 3 in order to manufacture knitted fabric by means of the said needles 3.
The machine further comprises a circular crown 4 arranged around the needle-holding cylinder 2 and having a plurality of radial grooves 5 and auxiliary radial grooves 6 that are open on a radially inner edge of the circular crown 4, i.e. towards the central axis "X-X". The radial grooves 5 and the auxiliary radial grooves 6 alternate along a circumferential development of the circular crown 4, i.e. each radial groove 5 is flanked by two auxiliary radial grooves 6 and each auxiliary radial groove 6 is flanked by two radial grooves 5. The circular crown 4 is moved in rotation around the central axis "X-X" together with the needle-holding cylinder 2, e.g. by means of the same motor.
Suitable devices, not shown, feed the yarns to be knitted on one or more yarn feeding points (known as feeds) usually arranged above the needle-holding cylinder 2. The circular intarsia knitting machine shown comprises four yarn feeds, each one configured for working with a respective group of needles 3 arranged along an arc of circle (e.g. a 90° arc) by means of an alternating rotary motion of the needles 3 around the central axis "X-X". The four feeds cooperate to form every knitted course by rotating in both directions.
Each yarn feed is provided with a yarn feeder 7 (which can be seen in a schematic manner in Figures 7A - 30A) consisting e.g. of an eyelet through which the yarn goes so as to be directed towards the needlebed for the needles 3. Each yarn feeder 7 is movable between an operating position and a rest position. In the operating position, the yarn feeder 7 is located radially outside the needlebed for the needles 3 so as to allow the heads 3A of the needles 3 to catch the textile yarn (Figures 7A-24A). In the rest position, the yarn feeder 7 is located radially inside the needlebed for the needles 3 and lifted from the needlebed for the needles 3 so as to prevent the heads 3A of the needles 3 from catching the textile yarn (Figures 25A-29A).
Each of the radial grooves 5 houses a first assembly made up of a plurality of metal flat parts that can slide radially in the respective radial groove 5 and also one with respect to the other. This first assembly, better shown in Figures 2 and 3, comprises a knockover sinker 8, a right open-work sinker 9, a left open-work sinker 10, two pushing units 11, one associated to the right open-work sinker 9 and the other one to the left open-work sinker 10, and a selector 12 for each of the pushing units 11.
The knockover sinker 8 comprises a main body shaped as a horizontal flat bar oriented as the radial groove 5, i.e. along a radial direction, and a vertical flat upright developing from the horizontal flat bar. A pin 13 having a per se known shape is arranged on an upper end of the vertical flat upright and faces the central axis "X-X" when the first assembly is properly mounted to the machine. The knockover sinker 8 further comprises a flat butt 14 extending vertically upwards from the horizontal flat bar and at a distance from a radially outer end (with respect to the central axis "X-X") of the horizontal flat bar. The knockover sinker 8 is made up of a single flat metal part, e.g. a cut part. The pins 13 of the knockover sinkers 8 are configured for cooperating with the needles 3 for manufacturing plain knitted fabric.
The right open-work sinker 9 comprises a main body shaped as a horizontal flat bar and a vertical flat upright developing from the horizontal flat bar. A protrusion 15 is arranged on an upper end of the flat upright. The protrusion 15 extends like a sort of arm, when the first assembly is properly mounted to the machine, towards the central axis "X-X" and is offset laterally with respect to a lying plane of the respective main body. The right open-work sinker 9 further comprises a flat butt 16 extending vertically upwards from the horizontal flat bar and is placed near a radially outer end (with respect to the central axis "X-X") of the horizontal flat bar. The right open-work sinker 9 is made up of a single flat metal part, e.g. a cut, stamped and/or bent part.
The left open-work sinker 10 comprises the same elements as the right open-work sinker 9 and is structurally identical with or corresponding to the right open-work sinker 9, except for the fact that the respective protrusion 15 is offset/displaced, with respect to its main body, to the opposed side. The right open-work sinker 9 and the left open-work sinker 10 therefore have respective protrusions 15 that are laterally displaced in opposed directions with respect to its main body and with respect to the knockover sinker 8 placed between them. When the first assembly is properly mounted in the respective radial groove 5, the right open-work sinker 9 and the left open-work sinker 10 are arranged on opposed sides of the respective knockover sinker 8 (Figure 3). The right open-work sinker 9 and the left open-work sinker 10 exhibit respective protrusions 15 that are laterally offset towards opposed sides of said knockover sinker 8 and placed above the pin 13 of the respective knockover sinker 8. Moreover, the butt 14 of the knockover sinker 7 is radially placed between the butt 16 and the protrusion 15 of the respective open- work sinkers 9, 10. The two protrusions 15 are configured for loading and stretching an interstitch and arrange it on a single needle 3 or on two adjacent needles 3 placed on opposed sides of the respective knockover sinker 8 and form an open work. In a variant of embodiment, a single protrusion can be configured for loading and stretching a respective interstitch and arrange it on a single needle 3 or on two adjacent needles 3.
The two pushing units 11 of the first assembly are identical with one another. Each of the pushing units 11 comprises a horizontal flat bar and a butt 17 that is flat, is placed on a radially outer end, with respect to the central axis "X-X", of the horizontal flat bar and extends vertically upwards. The pushing unit 11 further has an abutment surface facing the central axis "X-"X and configured for resting against the respective open- work sinker 9, 10. The abutment surface of the pushing unit 11 is placed near the butt 17 of said pushing unit 11, i.e. near said radially outer end of the horizontal flat bar. Also the pushing unit 11 is made up of a single flat metal part, e.g. a cut part. When the first assembly is properly mounted in the respective radial groove 5 (Figure 3), the horizontal flat bar of each pushing unit 11 is located under and in contact with the flat bar of the respective open- work sinker 9, 10 and the abutment surface faces the radially outer end of the respective open- work sinker 9, 10. The knockover/terry sinker 8 is placed between the right and left open- work sinkers 9, 10.
Each of the two selectors 12 is a metal, basically flat element mainly developing vertically when it is properly mounted in the machine. The selector 12 has a base portion 18 with a rounded profile and configured for oscillating around an axis tangent to a horizontal circumference with its center in the central axis "X-X". The selector 12 lies and oscillates in a radial plane. The selector 12 further exhibits an abutment portion 19 at a distance from the base portion 18, pointing towards the central axis "X-X" and configured for indirectly acting upon the respective open- work sinker 9, 10 through the respective pushing unit 11. The selector 12 further has a tooth 20 located on an edge of the flat element radially opposed to the abutment portion 19 and radially pointing outwards, i.e. to the opposed side with respect to the central axis "X-X". The abutment portion 19 has a rounded projection configured and sized for resting against the radially outer end of the horizontal flat bar of the respective pushing unit 11 of the first assembly.
Each selector 12 is oscillating in the radial plane between a rest position and an operating position. In the rest position, the abutment portion 19 of the selector 12 is located in a radially outer position and does not get in contact with the respective pushing unit 11. In the operating position, the selector 12 is rotated towards the central axis "X-X", the abutment portion 19 of the selector 12 is located in a radially inner position and is configured for resting and pushing against the respective pushing unit 11 towards the central axis "X-X". The pushing units 11 are configured in their turn for pushing the open- work sinkers 9, 10. The switching from the rest to the operating position of the selector 12 is caused by selecting actuators 21 (Figures 6, 7A-30A and 7B-30B) acting upon the tooth 20 of the selector 12 and whose structure shall be described in more detail below. In the embodiment shown by way of example, there are four selecting actuators 21 (Figure 6) which are stationary with respect to the casing and are arranged at the same angular distance (e.g. 90° from one another) around the circular crown 4. In particular, each of said selecting actuators 21 is located on a yarn feed.
Also the knockover sinker 8 is pushed by a respective pushing unit 11' and by a respective selector 12', which are wholly similar to the pushing unit 11 and to the selector 12. For this reason the same elements have been referred to with the same reference numerals with an apostrophe. The selector 12' exhibits a base portion 18' and an abutment portion 19' at a distance from the base portion 18', pointing towards the central axis "X-X" and configured for indirectly acting upon the respective knockover sinker 8 through the respective pushing unit 11'. The selector 12' further has a tooth 20' located on an edge of the flat element radially opposed to the abutment portion 19' and radially pointing outwards, i.e. to the opposed side with respect to the central axis "X-X". The abutment portion 19' has a rounded projection configured for resting against the radially outer end of the respective horizontal flat bar of the pushing unit 11'. Each of the pushing units 11' further exhibits a respective butt 20' and a respective abutment surface configured for resting against the respective knockover sinker 8. The knockover sinker 8 is further provided with a nose 22 so as to make terry stitches in cooperation with the needles 3. As can be observed, the position of the tooth 20' of the selector 12' differs from the one of the teeth 20 of the two selectors 12, so that the selecting actuators 21 can catch the teeth 20 or as an alternative the teeth 20' depending on whether the first assembly should work for making a hole in the fabric or make a terry stitch, respectively.
Each of the auxiliary radial grooves 6 houses a second assembly which is also made up of a plurality of metal flat parts that can slide radially in the respective auxiliary radial groove 6 and also one with respect to the other. This second assembly, better shown in Figures 4 and 5, comprises a single knockover sinker 8, a respective pushing unit 11' and a respective selector 12' which are identical or basically identical with the ones described above, so that they will not be described again here and in Figures 4 and 5 the same numerals as in Figures 2 and 3 have been used for these and for parts thereof. The selecting actuators 21 can interact also with the second assemblies in the same manner as described above for the knockover sinkers 8 of the first assemblies. Knockover sinkers 8 provided with the right open-work sinker 9 and with the left open-work sinker 10 are alternated with single knockover sinkers 8, i.e. without the right open-work sinker 9 and the left open-work sinker 10.
A guiding ring 23 (see Figure 6), consisting of one or more parts, is operatively associated to the circular crown 4. The guiding ring 23 is coaxial with the central axis "X-X" and is for instance stationary like the casing, i.e. the circular crown 4 is rotatable with respect to the guiding ring 23 around the central axis "X-X". The selecting actuators 21 are stationary with respect to the guiding ring 23 and face laterally the circular crown 4 and the circular needlebed, and can be engaged indirectly upon command with the open- work sinkers 9, 10 and with the knockover sinkers 8. The needle-holding cylinder 2 and the circular crown 4 are rotatable around the central axis "X-X" with respect to the yarn feeds and to the selecting actuators 21.
In the embodiment shown, the guiding ring 23 develops over and under the circular crown 4 (Figures 7B - 30B) and has a plurality of guides extending around the central axis "X-X" and configured for engaging with the above described metal parts of the first assembly and of the second assembly. These guides are for instance grooves delimited by cams.
The butt 14 of the knockover sinker 8 of each first assembly and the butt 14 of the knockover sinker 8 of each second assembly engage into a first guide 24 obtained in an upper portion of the guiding ring 23. The first guide 24 is configured for radially moving the knockover sinkers 8 along the respective radial grooves 5 and the respective auxiliary radial grooves 6 when the circular crown 4 rotates with respect to the guiding ring 23 and around the central axis "X-X".
As can be seen in Figure 6, the first guide 24 has some portions with a radial width that basically corresponds to the size of the butts 14 of the knockover sinkers 8, alternating with other wider portions. Said larger portions are provided with or define a respective radially outer path and a respective radially inner path (with respect to the central axis "X-X") for said butts 14 and thus for the respective knockover sinkers 8. As a result, the first guide 24 defines a first trajectory 25 comprising said radially outer paths for all said wider portions, and a second trajectory 26 comprising radially inner paths for all said wider portions. Two of said wider portions are positioned upstream and downstream from each yarn feed and from each selecting actuator 21.
The butts 16 of the right and left open- work sinkers 9, 10 of each first assembly engage into a second guide 27, obtained again in the upper portion of the guiding ring 23. The second guide 27 is located in a radially outer position with respect to the first guide 24, i.e. it surrounds it. The second guide 27 comprises a plurality of paths defining a radially outer trajectory 28 that is basically circular, a radially inner path 29 that is basically circular, and a plurality of connecting portions 30 between the radially outer trajectory 28 and the radially inner trajectory 29 (Figure 6).
The butts 17, 17' of the pushing units 11, 11' engage into a third guide 31, obtained again in the upper portion of the guiding ring 23. Also the third guide 31 extends around the central axis "X-X" and defines a plurality of trajectories. In particular, the third guide 31 defines a radially outer trajectory 32 and a plurality of radially inner trajectories 33 placed one after the other around the central axis "X-X". The radially outer trajectory 32 of the third guide 31 is radially further outer with respect to the second guide 27, i.e. it surrounds it. Each of the radially inner trajectories 33 is bow-shaped and has opposed ends connected to the radially outer trajectory 32 of the third guide 31. Each of the radially inner trajectories 33 departs from the radially outer trajectory 32 of the third guide 31 getting near the central axis "X-X", and then gets away again from the central axis "X-X" then connecting again to the radially outer trajectory 32 of the third guide 31. Said radially inner trajectories 33 are superposed to the second guide 27, i.e. they define a part of the connecting portions 30 of the second guide 27. In the embodiment shown, there are eight radially inner trajectories 33. Said radially inner trajectories 33 are positioned upstream and downstream from each of the four yarn feeds and from each selecting actuator 21.
The base portions 18, 18' of all the 12, 12' are housed in a circular track 34 extending around the central axis "X-X" so as to slide therein. The circular track 34 is obtained in a lower portion of the guiding ring 23 and delimits one circular trajectory lying out of the radially outer trajectory 32 of the third guide 31, i.e. it surrounds it.
Each of the selecting actuators 21, known per se, is of magnetic or piezoelectric type and comprises a plurality of levers 35 arranged one above the other and movable together between a first position, e.g. a raised position, and a second position, e.g. a lowered position. In the first position, the levers lie at a distance from the teeth 20, 20' of the selectors 12, 12' so as not to interfere with said teeth 20, 20' when the selectors 12, 12' are in their rest positions. In particular, in the first position said teeth 20, 20' are positioned between the levers 35. In the second position, the levers 35 interfere with the teeth 20 of the selectors 12 associated to the open- work sinkers 9, 10 and/or with the teeth 20' of the selectors 12' associated to the knockover sinkers 8 moving in front of the selecting actuator 21 when the circular crown 4 rotates with respect to the guiding ring 23 and around the central axis "X-X", so as to move the selectors 12, 12' from the rest position to the operating position.
As shown in Figures 6 and 7A - 30A, the guiding ring 23 comprises four movable transfer cams 36 and four stationary auxiliary transfer cams 37 configured for catching and deviating the butts 16 of the open- work sinkers 9, 10.
An electronic control unit, not shown, is operatively connected to the motor or motors causing the rotation of the needle-holding cylinder 2 and of the circular crown 4, to the selecting actuators 21 and to further actuating units, if any, of the machine. The electronic control unit is configured/programmed for commanding the motor or motors and the selecting actuators 21 and said further actuating units, if any, of the machine. In particular, the electronic control unit is configured/programmed for selectively moving the levers 35 of the selecting actuators 21 so as to move the selectors 12, 12' singularly from the rest position to the operating position.
When making the open-work as described in further detail below, each of the yarn feeds with the respective yarn feeder 7 is configured for working with a respective group of needles 3 arranged along an arc of circle and with the corresponding open- work sinkers 9, 10 and knockover sinkers 8 and together with the selecting actuator 21 that is laterally offset (at a circumferential distance) e.g. of 90° with respect to said yarn feed. A movable transfer cam 36 and a stationary auxiliary transfer cam 37 work with a respective yarn feed, with a respective selecting actuator 21.
For the sake of simplicity, Figures 7A-30A show: one yarn feed (yarn feeder 7), the selecting actuator 21 working with said yarn feed and moved of 90° with respect to the yarn feed, the movable transfer cam 36 and the stationary auxiliary transfer cam 37 cooperating with said yarn feed and said selecting actuator 21. Figures 7A-30A further show: the group of needles 3, of knockover sinkers 8 and of open- work sinkers 9, 10 working with said yarn feed (yarn feeder 7) and said selecting actuator 21 and said transfer cams 36, 37. This group of needles 3, knockover sinkers 8 and open- work sinkers 9, 10 extends on about 45°. The selecting actuator 21 can be engaged upon command, indirectly, with each open- work sinker 9, 10 and with each knockover sinker 8 of said group.
In use and according to the method of the present invention, in order to make a portion of a plain knitted course (Figures 7A - 15A and 7B - 15B), the group of needles 3 with the respective group of knockover sinkers 8 (of the first and of the second assembly as described above) and with the group of knockover sinkers 9, 10 (of the first assembly as described above) is upstream from the respective selecting actuator 21 with respect to a first counterclockwise direction of rotation (Figures 7A and 7B). The needles 3 are in a lowered position (Figure 7B) and the open- work sinkers 9, 10 and the knockover sinkers 8 are in the backward position.
The needle-holding cylinder 2 and the circular crown 4 begin to rotate in the first counterclockwise direction while the selecting actuator 21 is not actuated, so that the selectors 12, 12' of the open- work sinkers 9, 10 and of the knockover sinkers 8 are not caught by the levers 35 and remain in their rest position. The butts 17, 17' of the pushing units 11, 11' go along the radially outer trajectory 32 of the third guide 31. The butts 16 of the right and left open- work sinkers 9, 10 of each first assembly go along the radially outer trajectory 28 of the second guide 27, and therefore the protrusions 15 of the respective open- work sinkers 9, 10 remain in a position radially at a distance from the central axis "X-X", i.e. in a backward or rest position in which they do not interact with the yarn making the stitch.
The butts 14 of the knockover sinkers 8 follow a part of the second trajectory 26 and a part of the first trajectory 25 of the first guide 24 causing a radial movement of said knockover/terry sinkers 8. The knockover sinkers 8 go backward and forward along the respective radial directions while the needles 3 are raised and then lowered so as to make a stitch with the textile yarn fed by the yarn feed while the needle-holding cylinder 2 and the circular crown 4 rotate in the first direction of rotation until they pass over said yarn feed (Figures 8A, 8B, 9A, 9B, 10A, 10B).
The needle-holding cylinder 2 and the circular crown 4 rotate on an angle of about 180° in the first counterclockwise direction of rotation and form a stitch until they reach the position of Figure 10A, then the direction of rotation of the needle-holding cylinder 2 and of the circular crown 4 is reverted. The needle-holding cylinder 2 and the circular crown 4 thus rotate in a second, clockwise, direction of rotation around the central axis "X-X" while the needles 3 are raised and then lowered so as to make a stitch with the textile yarn fed by the yarn feed in cooperation with the knockover sinkers 8 (Figures 11A - 14A and 11B - 14B) until the group of needles 3, the group of knockover sinkers 8 and the group of open- work sinkers 9, 10 are moved again upstream from the respective selecting actuator 21, with respect to the first counterclockwise direction of rotation (Figures 15A and 15B).
Now the direction of rotation of the needle-holding cylinder 2 and of the circular crown 4 is reverted again (Figures 16A and 16B). In order to make a portion of open-work knitted course, the control unit commands the selecting actuator 21 (by software control) so that it moves a first group of levers 35 from the first to the second position and vice versa, so as to catch only the selectors 12 of the open- work sinkers 9, 10 moving in front of said selecting actuator 21. The selectors 12 caught by the open- work sinkers 9, 10 are moved to the operating position, whereas the selectors 12' of all the knockover sinkers 8 are not caught and remain in their rest position. Thus all or a part of the open- work sinkers 9, 10 of the group are selected by the selecting actuator 21. Referring for the sake of simplicity to a pair of selectors 12 of a first assembly, said selectors 12 push the respective two pushing units 11 towards the central axis "X-X" so that the butts 17 of the pushing units 11 are deviated in the radially inner trajectory 33 of the third guide 31 placed immediately downwards from the selecting actuator 21 and follow it pushing in its turn the first and the second open- work sinker 9, 10. The butts 16 of the first and of the second open- work sinker 9, 10 go along one of the connecting portions 30 of the second guide 27 and get into the radially inner trajectory 29 of the second guide 27 and follow it for a preset angle of rotation described by the circular crown 4 and by the needle-holding cylinder 2 in counterclockwise direction. During this travel, the first and second open- work sinkers 9, 10 are moved radially towards the central axis "X-X" and towards a respective forward position, while the needles 3 are kept in a lowered position (Figures 17A, 17B). Therefore, the pushing units 11, by following the radially inner trajectory 33 of the third guide 31, get back to the radially outer trajectory 32 of said third guide 31 and push the selector 11 back to the rest position.
In the meanwhile, the needle 3 or the two needles 3 operatively associated to the pair of open- work sinkers 9 and 10 are raised and then lowered, if necessary together with other needles 3 to be operated on a given yarn feed without stretching the interstitches, while the needle-holding cylinder 2 and the circular crown 4 rotate in said first direction of rotation and travel on the yarn feed so as to load the textile yarn, fed by said yarn feed, onto the protrusions 15 of the open- work sinkers 9, 10 selected for making elongated interstitches (Figures 18A, 18B, 19A, 19B, 20A, 20B). In other words, when the pair of open- work sinkers 9 and 10 of said first assembly reaches the yarn feed, a knitted loop with elongated interstitches (which will make an open work) is formed, since the interstitches are loaded onto the protrusions 15 and not onto the pin 13 of the respective knockover sinker 8. During this movement the movable transfer cam 36 is kept in a rest position and does not interact with the butts 16 of the open- work sinkers 9, 10.
The counterclockwise rotation goes on until the groups of needles 3, of knockover sinkers 8 and of open- work sinkers 9, 10 pass over the movable transfer cam 36 (Figures 21A and 21B).
Now the movable transfer cam 36 is moved to a catching position and the counterclockwise direction (first direction of rotation) of the needle-holding cylinder 2 and of the circular crown 4 is stopped and reverted (Figure 22A and 22B).
During a following clockwise rotation (second direction of rotation) of the circular crown 4 and of the needle-holding cylinder 2 (Figures 23A - 26A and 23B- 26B), the selected open- work sinkers 9, 10 are moved again away from the central axis "X-X". In particular, during the counterclockwise rotation, the butts 16 of the first and second open- work sinkers 9, 10 first go along a portion of the radially inner trajectory 29 of the second guide 27, while the needles are kept in non-operating position, and are then deviated by the movable transfer cam 36, in the catching position, on a connecting portion 30 corresponding to an intermediate position, between the backward and the forward position, of the open- work sinkers 9, 10. In the meanwhile the needles 3 are raised in a withdrawn position so that the protrusions 15 of the selected open- work sinkers 9, 10 are located beside the heads 3A of the needles 3 and moreover the yarn feeder 7 is moved to the respective rest position (Figures 25A and 25B).
Now the butts 16 of the first and of the second open- work sinker 9, 10 are deviated by the stationary auxiliary transfer cam 37 on the radially outer trajectory 28 of the second guide 27 and move the selected open- work sinkers 9, 10 as far as the backward position so as to unload the interstitch, which lies on the protrusions 15, inside the heads 3A of the needles 3 (Figures 26A and 26B). The clockwise rotation goes on while the needles 3 are lowered and the groups of needles 3, open- work sinkers 9, 10 and knockover sinkers 8 pass over the yarn feed without the needles 3 picking the textile yarn, since the yarn feeder 7 is in the rest position. The needle-holding cylinder 2 and the circular crown 4 rotate in the second direction of rotation until the group of needles 3, the group of knockover sinkers 8 and the group of open- work sinkers 9, 10 are moved back upstream from the respective selecting actuator 21 with the needles 3 lowered and the open- work sinkers 9, 10 in the backward position (Figures 27A and 27B). During the clockwise rotation described above, the needles 3 therefore do not make any stitch but only contribute to picking and withdrawing the interstitch unloaded from the protrusions 15 inside the heads 3A of the needles 3, so as to then make the open work.
Once the group of needles 3, the group of knockover sinkers 8 and the group of open- work sinkers 9, 10 are moved back upwards of the respective selecting actuator 21, the rotation is stopped and reverted again. The selecting actuator 21 is kept in a non-operating position and the needle-holding cylinder 2 and the circular crown 4 are put in rotation in the first counterclockwise direction of rotation on an angle of about 180° (Figures 28A -30A and 28B - 30B), keeping the open- work sinkers 9, 10 in the backward position, the needles 3 in the lowered, non-operating position and the yarn feeder 7 in the rest position, so as to reset the operating sequence without making any stitch. Now, after moving the yarn feeder 7 back to the operating position, the operating cycle can be resumed, with stitch formation, from the position shown in Figures 10A, 10B according to the operating modes as already described above.
In a variant of the method according to the invention, during the clockwise rotation (second direction of rotation) of the circular crown 4 and of the needle-holding cylinder 2 as described above and shown in Figures 23A -26A and 23B- 26B, the yarn feeder 7 is not moved to the rest position and the needles 3 pick another yarn so as to make a stitch cooperating with the knockover sinkers 8. Therefore, in this variant, beyond contributing to the open-work, the needles 3 also make a stitch. As a result, it is not necessary to reset the operating sequence without making any stitch, i.e. follow the sequence of Figures 28A - 30A and 28B - 30B, but the work can be resumed directly from the configuration of Figures 10A, 10B.
In further embodiments, not shown in the accompanying drawings, a double interstitch is made on the protrusions 15 of a right open-work sinker 9 and of a left open-work sinker 10.
In an embodiment, the double interstitch is made by letting the needles 3 and the open- work sinkers 9, 10 cooperate with a first feed and with a second feed located downstream from the first feed. While the needle-holding cylinder 2 and the circular crown 4 rotate in the first direction of rotation, the textile yarn is loaded onto the protrusions 15 of the selected open- work sinkers 9, 10, the first time on the first yarn feed and the second time on the second yarn feed. Thus, in this step the needle-holding cylinder 2 and the circular crown 4 rotate on an angle above 180°, e.g. above 270°. Then, the needle-holding cylinder 2 and the circular crown 4 revert the direction of rotation and, while they rotate in the second direction of rotation, the two elongated interstitches are unloaded into the heads 3A of the needles 3 on the second feed (i.e. the first feed they meet after inverting the direction of rotation).
In a different embodiment, the double interstitch is made by letting the needles 3 and the open- work sinkers 9, 10 cooperate with one feed. The textile yarn is loaded onto the open- work sinkers 9, 10 on said single feed, while the needle-holding cylinder 2 and the circular crown 4 rotate in the first direction of rotation, and is loaded again onto the same open- work sinkers 9, 10 on the same feed while the needle-holding cylinder 2 and the circular crown 4 rotate in the second direction of rotation. Then, the needle-holding cylinder 2 and the circular crown 4 revert the direction of rotation and, while they still rotate in the first direction of rotation, the two elongated interstitches are unloaded into the heads 3A of the needles 3 still on said single feed.
In order to make terry stitches in the fabric, by means of the noses 22 of the knockover sinkers 8 both of the first and of the second assemblies , the control unit commands the selecting actuator 21 so that it moves a second group of levers 35 from the first to the second position and then vice versa in programmed angular positions of the needle-holding cylinder 2 and of the circular crown 4, so as to catch specific selectors 12' of the knockover sinkers 8. The selectors of the open- work sinkers 9, 10 are not caught and remain in their rest position.
Referring for the sake of simplicity to a single selector 12' of a knockover sinker 8, said selector 12' pushes the respective pushing unit 11' towards the central axis "X-X" so that the butt 17' of the pushing unit 11' is deviated in the radially inner trajectory 33 of the third guide 31 placed immediately downwards from the selecting actuator 21 and follows it pushing in its turn radially the respective knockover sinker 8.
This radial push is exerted while the knockover sinker 8 is in one of the widest portions of the first guide 24 and moves the knockover sinker 8 from the first trajectory 25 to the second trajectory 26 of the first guide 24, i.e. it anticipates the radial entry of the knockover sinker 8 with respect to the cams only of the first guide 24 when forming a plain stitch as described above. Thus the nose 22 of the knockover sinker 8 cooperates with a pair of needles 3 (in a per se known manner, which is not further described here) so as to form a terry stitch. This operating mode can be implemented while the circular crown 4 rotates in clockwise direction or in counterclockwise direction.
The present invention achieves important advantages both from a structural and a functional point of view.
As a matter of fact, with the method according to the invention it is easily possible to make the desired selectors and/or auxiliary selectors operating and thus manufacture complex plain, open-work and/or terrycloth knitted fabrics with the most different features, on the same machine and with high flexibility and speed.
The machine according to the invention allows to make open work and/or terry stitches and also other types of motifs with high speeds, thus dramatically reducing manufacturing times for even complex and sophisticated tubular knitted fabrics.

Claims

A method for manufacturing an open-work knitted fabric in a circular knitting machine; wherein the circular knitting machine comprises:
a needle-holding cylinder (2) and a circular crown (4) having a common central axis (X-X);

a plurality of needles (3) installed on the needle-holding cylinder (2), movable along a longitudinal development thereof and each having a head (3A) arranged around the central axis (X-X) so as to define a circular needlebed;

a plurality of knockover sinkers (8) installed in the circular crown (4), movable along radial directions with respect to said central axis (X-X) and each having a pin (13) configured for cooperating with the needles (3) so as to make a knitted fabric;

a plurality of open-work sinkers (9, 10) installed in the circular crown (4), placed beside the knockover sinkers (8), movable along radial directions with respect to said central axis (X-X) and each having a protrusion (15) configured for cooperating with the needles (3) so as to make an open-work knitted fabric;

at least one yarn feed operatively associated to a respective group of needles (3), to a respective group of knockover sinkers (8) and to a respective group of open-work sinkers (9, 10) so as to feed at least one textile yarn to the circular needlebed;

wherein the needle-holding cylinder (2) and the circular crown (4) are rotatable around the central axis (X-X) with respect to the yarn feed;

wherein the method comprises:
i. rotating the needle-holding cylinder (2) and the circular crown (4) around the central axis (X-X) and radially moving selected open-work sinkers (9, 10) of said group of open-work sinkers (9, 10) towards the central axis (X-X) and towards a respective forward position; lifting and then lowering the needles (3) of said group of needles (3) beside the selected open-work sinkers (9, 10) placed in the forward position, while the needle-holding cylinder (2) and the circular crown (4) rotate and pass over said at least one yarn feed so as to load the textile yarn fed by said yarn feed onto the protrusions (15) of the selected open-work sinkers (9, 10) so as to make elongated interstitches;

ii. rotating the needle-holding cylinder (2) and the circular crown (4) around the central axis (X-X) and radially moving the selected open-work sinkers (9, 10) away from the central axis (X-X), towards a respective backward position, lifting the needles (3) at least in a withdrawn and/or unloaded position, so as to unload the interstitch on the protrusions (15) within the heads (3A) of the needles (3), and continuing rotating the needle-holding cylinder (2) and the circular crown (4) until said at least one yarn feed is passed over and then lowering the needles (3) while the selected open-work sinkers (9, 10) are in the respective backward position;

the method being characterized in that step i. is executed while the needle-holding cylinder (2) and the circular crown (4) rotate in at least a first direction of rotation, and step ii. is executed while the needle-holding cylinder (2) and the circular crown (4) rotate in a second direction of rotation opposed to the first one; or in that step i. is executed while the needle-holding cylinder (2) and the circular crown (4) rotate in a first direction of rotation and

then in a second direction of rotation opposed to the first one, and step ii. is executed while the needle-holding cylinder (2) and the circular crown (4) rotate in the first direction of rotation.
The method according to claim 1, wherein the selected open-work sinkers (9, 10) are selected by means of a selecting actuator (21) laterally facing the circular needlebed, which can be engaged under control, either directly or indirectly, with each of the open-work sinkers (9, 10) of said respective group of open-work sinkers (9, 10); wherein said at least one yarn feed is circumferentially at a distance from the respective selecting actuator (21); wherein the needle-holding cylinder (2) and the circular crown (4) are rotatable around the central axis (X-X) with respect to the selecting actuator (21).
The method according to claim 2, comprising before step i.:
moving the group of needles (3), the group of knockover sinkers (8) and the group of open-work sinkers (9, 10) upstream from the respective selecting actuator (21) with respect to the first direction of rotation, wherein the open-work sinkers (9, 10) are in the backward position and actuating the selecting actuator (21).
The method according to claim 1, 2, or 3, wherein in step ii., while rotation continues until said at least one yarn feed is passed over, the needles (3) do not pick up the textile yarn from said yarn feed or pick up a further yarn so as to make a stitch in cooperation with the knockover sinkers (8).
The method according to claim 1, 2, 3 or 4, wherein step ii. comprises:
radially moving the selected open-work sinkers (9, 10) away from the central axis (X-X) in an intermediate position by keeping the needles (3) in a non-operating position and/or in a position below the withdrawn position;

lifting the needles (3) in the withdrawn position, so that the protrusions (15) of the selected open-work sinkers (9, 10) lie beside the heads (3A) of the needles (3);

further radially moving the selected open-work sinkers (9, 10) away from the central axis (X-X) to said backward position, so as to unload the interstitches lying on the protrusions (15) into the heads (3A) of the needles (3);

continuing rotation until the yarn feed is passed over without the needles (3) picking up the textile yarn from the yarn feed, or so that the needles (3) reach an unloaded and/or withdrawn position and pick up a further yarn from the yarn feed so as to make a stitch in cooperation with the knockover sinkers (8);

lowering the needles (3) while the selected open-work sinkers (9, 10), after unloading the interstitch, are in the backward position.
The method according to claim 4 or 5 when dependent on claim 3, wherein a yarn feeder (7) of said yarn feed is moved in a rest position so that the needles (3) do not pick up the textile yarn from said yarn feed; or wherein the yarn feeder (7) of said yarn feed remains in an operating position so that the needles (3) pick up the further textile yarn from said yarn feed, and/or wherein the needle-holding cylinder (2) and the circular crown (4) rotate in the second direction of rotation until the group of needles (3), the group of knockover sinker (8) and the group of open-work sinkers (9, 10) are moved back upstream from the respective selecting actuator (21).
The method according to claim 6, wherein during steps i. and ii., all the open-work sinkers (9, 10) of said groups of open-work sinkers (9, 10) are selected so as to make an open-work knitted fabric, or wherein only some of the open-work sinkers (9, 10) of said group of open-work sinkers (9, 10) are selected so as to make portions of open-work knitted fabric,
and/or wherein the method comprises:
keeping the selecting actuator (21) in a non-operating configuration;

putting the needle-holding cylinder (2) and the circular crown (4) in rotation in the first direction of rotation so that each of the open-work sinkers (9, 10) of the group of open-work sinkers (9, 10) remains in the backward position until the yarn feed is passed over, and while the open-work sinkers (9, 10) remain in the backward position and the needles (3) remain in the lowered position, so as to reset the operating sequence without making any stitch.
The method according to claim 7, comprising:
reverting the direction of rotation of the needle-holding cylinder (2) and the circular crown (4) and lifting and then lowering the needles (3) so as to make a stitch with the textile yarn fed by said yarn feed in cooperation with the knockover sinkers (8) while the needle-holding cylinder (2) and the circular crown (4) rotate in the second direction of rotation until the group of needles (3), the group of knockover sinkers (8) and the group of open-work sinkers (9, 10) are moved again upstream from the respective selecting actuator (21) with respect to the first direction of rotation.
The method according to claim 8, comprising:
keeping the selecting actuator (21) in the non-operating configuration;

putting the needle-holding cylinder (2) and the circular crown (4) in rotation around the central axis (X-X) and in the first direction of rotation while each of the open-work sinkers (9, 10) of the group of open-work sinkers (9, 10) remains in the backward position;

lifting and then lowering the needles (3) so as to make a stitch with the textile yarn fed by said yarn feed in cooperation with the knockover sinkers (8) while the needle-holding cylinder (2) and the circular crown (4) rotate in the first direction of rotation until said yarn feed is passed over;

reverting the direction of rotation of the needle-holding cylinder (2) and the circular crown (4), lifting and then lowering the needles (3) so as to make a stitch with the textile yarn fed by said yarn feed in cooperation with the knockover sinkers (8) while the needle-holding cylinder (2) and the circular crown (4) rotate in the second direction of rotation until the group of needles (3), the group of knockover sinkers (8) and the group of open-work sinkers (9, 10) are moved again upstream from the respective selecting actuator (21) with respect to the first direction of rotation.
The method according to claim 5, wherein radially moving the selected open-work sinkers (9, 10) away from the central axis (X-X) in the intermediate position comprises: moving a transfer cam (36) so as to catch and deviate a butt (16) of each selected open-work sinkers (9, 10), and/or wherein further moving the selected open-work sinkers (9, 10) as far as said backward position comprises: moving a further transfer cam (37) so as to catch and deviate the butt (16) of each selected open-work sinkers (9, 10).
The method according to one of the claims 1 to 10, wherein each of the knockover sinkers (8) is placed beside a pair of open-work sinkers (9, 10) and each pair of open-work sinkers (9, 10) contributes to make an interstitch loop.
A circular knitting machine, comprising:
a needle-holding cylinder (2) and a circular crown (4) having a common central axis (X-X);

a plurality of needles (3) installed on the needle-holding cylinder (2), movable along a longitudinal development thereof and each having a head (3A) arranged around the central axis (X-X) so as to define a circular needlebed;

a plurality of knockover sinkers (8) installed in the circular crown (4), movable along radial directions with respect to said central axis (X-X) and each having a pin (13) configured for cooperating with the needles (3) so as to make a knitted fabric;

a plurality of open-work sinkers (9, 10) installed in the circular crown (4), placed beside the knockover sinkers (8), movable along radial directions with respect to said central axis (X-X) and each having a protrusion (15) configured for cooperating with the needles (3) so as to make an open-work knitted fabric;

at least one yarn feed operatively associated to a respective group of needles (3), to a respective group of knockover sinkers (8) and to a respective group of open-work sinkers (9, 10) so as to feed at least one textile yarn to the circular needlebed;

wherein the needle-holding cylinder (2) and the circular crown (4) are rotatable around the central axis (X-X) with respect to the yarn feed;

wherein the circular knitting machine is configured for:
i. rotating the needle-holding cylinder (2) and the circular crown (4) around the central axis (X-X) with selected open-work sinkers (9, 10) of said group of open-work sinkers (9, 10) displaced towards the central axis (X-X) in a respective forward position; lifting and then lowering needles (3) of said group of needles (3) beside the selected open-work sinkers (9, 10) placed in the forward position, while the needle-holding cylinder (2) and the circular crown (4) rotate and pass over said at least one yarn feed so as to load the textile yarn fed by said yarn feed onto the protrusions (15) of the selected open-work sinkers (9, 10) so as to make elongated interstitches;

ii. rotating the needle-holding cylinder (2) and the circular crown (4) around the central axis (X-X) and radially moving the selected open-work sinkers (9, 10) away from the central axis (X-X) while the needles (3) are lifted at least in a withdrawn and/or unloaded position, so as to unload the interstitch lying on the protrusions (15) into the heads (3A) of the needles (3), and continuing rotating the needle-holding cylinder (2) and the circular crown (4) until said at least one yarn feed is passed over and then lowering the needles (3) while the selected open-work sinkers (9, 10) are in the respective backward position;

the circular knitting machine being characterized in that step i. is executed while the needle-holding cylinder (2) and the circular crown (4) rotate in at least a first direction of rotation, and step ii. is executed while the needle-holding cylinder (2) and the circular crown (4) rotate in a second direction of rotation opposed to the first one;

or wherein step i. is executed while the needle-holding cylinder (2) and the circular crown (4) rotate in a first direction of rotation and then in a second direction of rotation opposed to the first one, and step ii. is executed while the needle-holding cylinder (2) and the circular crown (4) rotate in the first direction of rotation.
The machine according to claim 12, comprising at least one selecting actuator (21) laterally facing the circular needlebed, which can be engaged under control, either directly or indirectly, with each of the open-work sinkers (9, 10) of said respective group of open-work sinkers (9, 10); wherein said at least one yarn feed is circumferentially at a distance from the respective selecting actuator (21); wherein the needle-holding cylinder (2) and the circular crown (4) are rotatable around the central axis (X-X) with respect to the selecting actuator (21); wherein the selected open-work sinkers (9, 10) are selected by means of said selecting actuator (21).
The machine according to claim 12 or 13, wherein said machine is configured for:
radially moving the selected open-work sinkers (9, 10) away from the central axis (X-X) in an intermediate position by keeping the needles (3) in a non-operating position and/or in a position below the withdrawn position;

lifting the needles (3) at least in the withdrawn position, so that the protrusions (15) of the selected open-work sinkers (9, 10) lies beside the heads (3A) of the needles;

further radially moving the selected open-work needles (9, 10) away from the central axis (X-X) as far as said backward position, so as to unload the interstitches lying on the protrusions (15) into the heads (3A) of the needles (3);

continuing rotation until the yarn feed is passed over without the needles (3) picking up the textile yarn from the yarn feed or while the needles (3) reach the unloaded and/or withdrawn position and pick up a further yarn from the yarn feed so as to make a stitch in cooperation with the knockover sinkers (8);

lowering the needles (3) while the selected open-work sinkers (9, 10), after unloading the interstitch, are in the backward position,

and/or wherein in order to make the open work, the yarn feed is angularly offset with respect to the respective selecting actuator (21) of an angle of 90° to 180°.
The machine according to claim 13 or 14, wherein the group of needles (3), the group of knockover sinkers (8) and the group of open-work sinkers (9, 10), operatively associated to a yarn feed and to a selecting actuator (21), have an angular extension, e.g. of 180° or less, e.g. of 90° or less, e.g. 45°, and/or wherein the machine comprises four yarn feeds angularly offset one to the other, and four selecting actuators (21) angularly offset one to the other, and wherein each yarn feed, in order to make the open work, is angularly offset with respect to the respective selecting actuator (21).