CN108729005B

CN108729005B - Selector head for a circular knitting machine, circular knitting machine and method for moving the needles of a circular knitting machine

Info

Publication number: CN108729005B
Application number: CN201810307392.4A
Authority: CN
Inventors: A·罗纳地; M·洛德里尼; M·阿尔吉西
Original assignee: Santoni SpA
Current assignee: Santoni SpA
Priority date: 2017-04-24
Filing date: 2018-04-08
Publication date: 2020-08-04
Anticipated expiration: 2038-04-08
Also published as: TW201839201A; IT201700044778A1; CN108729005A; WO2018197972A1; TWI770143B

Abstract

A selector head for circular knitting machines comprising: a first set of needle selection blades (203) and a second set of needle selection blades (204), each needle selection blade head (203,204) comprising a plurality of needle selection blade heads (205,206) arranged in succession along a common axis (K-K). The second set of needle selection blades (204) and the first set of needle selection blades (203) are arranged one after the other along the common axis (K-K). The first group of needle selection knives (203) are configured to engage with the teeth (35) of the selector group (9) of the circular knitting machine (1) if the relative rotation of the needle-holding needle cylinder (2) of the circular knitting machine (1) with respect to the drive cam (C) occurs in a first direction of rotation (CCW). The second selector blade head (204) is configured to engage with the teeth (35) of the selector set (9) if the relative rotation of the needle-holding needle cylinder (2) of the circular knitting machine (1) with respect to the drive cam (C) occurs in a second direction of rotation (CW) opposite to the first direction of rotation (CCW).

Description

Selector head for a circular knitting machine, circular knitting machine and method for moving the needles of a circular knitting machine

Technical Field

The invention relates to a selector head for a circular knitting machine, a circular knitting machine and a method for moving the needles of a circular knitting machine. In particular, the invention relates to a movement mechanism for the needle. More particularly, the invention relates to an element structure for driving a needle by converting a relative rotational movement between a needle-holding element and a driving cam into a prescribed axial movement of the needle.

Background

As is well known, circular knitting machines have: a needle-holding element (needle cylinder and/or dial) on which one or more needles are arranged along a circular track (circular needle bed); and an apparatus for easily controlling the movement of the needles for forming the knitted fabric. The device for controlling the needles of a needle-holding needle cylinder comprises an actuation triangle arranged around the cylinder itself, and actuation means configured for operatively connecting the triangle with the needles. These driving means are also defined as "flat parts", which are inserted in the needle groove of the needle below the latter and have a butt for cooperating with the runways defined by the cams.

It is known to construct triangles and runways defined by the triangles so that the axial action of the needles allows miss-knitting, tucking and looping.

For example, the applications publications EP 1620590 and EP 1620591 of the same applicant both disclose circular knitting machines equipped with a cylinder having an axial groove. Each of a plurality of needles is received in one of the axial slots and upon rotation of the barrel, drive means, also located in the axial slot, interact with the needle to cause drive thereof. The drive means of each needle comprise: auxiliary needles connected to the respective needle and able to oscillate radially in the groove in order to selectively engage their own butt with the runway defined by the driving cams; a pusher head having an upper portion engageable with the lower end of the sub-needle, the pusher head also being capable of engaging with a corresponding track defined by a drive cam; a selector group that can oscillate in a radial plane so as to coincide with a respective runway defined by a drive triangle and that can be driven by a selected device, wherein the selector group has an upper portion that can be abutted against a lower portion of the pusher head. It can be noted that the runways of the oscillating selector groups have a raising height which lifts the pusher head of the selector group and with the needles to the knockover height, another raising height at which the needles are lifted to a lesser extent and the stitches do not fall over the needle bar tuck. The tuck lift is upstream of the looping lift. To effect the descent of the stitch, the needles are held or guided by the selected needle device in the active position to engage with the butt and therefore with the tucker lift first and then with the stitch lift. The selector group engaged with the tuck-lift height raises the pusher head, which then descends, thus causing the sub-needle to be temporarily switched to the inactive position. Another lift, caused by the selector group and by the loop-forming lifting height, causes the needles to be lifted after the knitting loop drop-off point. In order to achieve tucking, the selector plate set is then engaged only with the tuck-lift height. In this case, there is no further lifting.

Publication IT1203500 discloses a knitting machine for knitted fabrics comprising a needle raising cam with two runways for the butt of the driving element, which then acts on the sub-needle and on the needle. These two runways are a first runway for normally performing loop formation and a second runway for performing tuck stitch at a parallel and lower position with respect to the first runway. Each of the runways comprises: a rise height, a base horizontal length, and a fall length. In the usual execution of the loop formation, the butt of the driving element engages with the first (upper) track. The needles are lifted to a height so that the preformed loop falls onto the shank of the needles. When tucking is performed, the butt of the drive element follows the second (lower) track. The needle is raised to a height such that the preformed loop does not reach the rod.

Disclosure of Invention

In the construction of circular knitting machines such as those described above, the applicant has perceived that there are some drawbacks.

First of all, the present application notes that the known machines as described above have very large axial and circumferential dimensions and that these known machines cannot be made with a diameter lower than a predetermined diameter, since in doing so it is not possible to provide the known drive means with needles having such characteristics for allowing all the movements required for knitting.

The applicant has further noticed that in the known solutions, particularly in the case of knitting machines with needle-holding needle cylinders having a small diameter, for example lower than 10 inches (about 250mm), it is not possible to introduce a large number of passes (e.g. the four mentioned above), since there is not enough space around the cylinder for housing all the necessary drive means.

The dimensions of the known machines have, at critical points, a negative effect on the moment of inertia, which limits the rotation speed and therefore the knitting speed.

The applicant has also noticed that the known machines, as described above, have a limited number of possible movements of the needles, which limits the production flexibility.

In particular, the applicant has also noted that in the known machines it is possible to selectively make the structure of tuck or stitch cams to occupy space along the circumferential development of the cam bodies. This involves a limitation of the movement imparted to the needles and/or a limitation of the number of yarn paths for a needle-holding needle cylinder of a predetermined diameter.

The applicant has noticed that these drawbacks are even worse if the circular knitting machine has a reciprocating rotary rotation, i.e. if the machine works and knits fabric by reciprocating rotation of the needle cylinder with respect to the triangle base about a central or rotation axis (in clockwise and counterclockwise directions).

In particular, the applicant has noted that the solutions of the documents EP 1620590 and EP 1620591 result in: when performing tucking, it is necessary that the butt of the oscillating selector group must disengage from the corresponding runway (i.e. be retracted in the cylinder) after the tucking-up level but before the looping-up level, in order not to check said looping-up level. This means that space for the needle selection device must be obtained between two elevations, thereby increasing the circumferential arrangement of the cams. In the case of a reciprocating knitting machine, this space is required on both sides of the cams, which define the loop-forming rise height.

Under such circumstances, in various aspects and/or embodiments, one object on which the invention is based is to propose a circular knitting machine in which the knitting characteristics achieved are the same as, or also more than, those of the prior art, which has smaller dimensions and allows the production of fabrics with relatively small diameters, for example below 165 mm.

Another object of the present invention is to propose a circular knitting machine and a method for moving the needles which allow to increase the plurality of movements imparted to the needles in order to achieve a higher production flexibility, i.e. in order to produce different types of fabric having a plurality of characteristics different from each other.

Another object of the present invention is to propose a circular knitting machine and a method for moving the needles which allow to increase the number of defined feed points or feed paths (feeds) with the same diameter of the needle-holding element with respect to the prior art.

Another object of the present invention is to propose a circular knitting machine featuring a simple and rational structure.

Another object of the invention is to create an alternative to the prior art for implementing circular knitting machines and/or to open up new design possibilities.

It is also an object of the present invention to achieve the intended aim of a circular knitting machine with reciprocating oscillating action.

These and other possible objects, which will be better apparent from the following description, are substantially achieved by a circular knitting machine and a method of moving said needles according to one or more of the appended claims, as well as according to the following aspects and/or embodiments, which are more recombined and which can also be combined with said claims.

In the description of the invention and in the appended claims, the words "upper", "lower", "above" and "below" relate to the arrangement of the machine during normal operation with the central axis of rotation in the vertical position and the cylinder needles pointing upwards.

In the present description and in the appended claims, the words "axial", "circumferential", "radial" relate to the central axis.

Some aspects of the invention are described below.

In one aspect, the present invention is directed to a circular knitting machine comprising a frame; a needle holding cylinder mounted on the frame and having a plurality of longitudinal needle slots arranged around a central axis of the needle holding cylinder; a plurality of needles, each needle received in a respective longitudinal needle slot; at least one yarn feeder operatively associated with the needle; a drive cam arranged around the needle-holding cylinder and movable relative to the needle-holding cylinder about a central axis for inducing or allowing a movement of the needle along a longitudinal needle slot such that a stitch formation is effected by the needle; a drive chain for each needle, which is inserted in the respective longitudinal needle slot, is located below the respective needle, and which is operatively placed between the respective needle and the drive triangle.

In one aspect, the drive chain comprises: a sub-needle arranged below the needle and preferably slidingly arranged in a respective longitudinal needle groove.

In one aspect, the drive chain comprises a selector group arranged below the auxiliary needle, having at least one respective butt radially movable between an active position, in which it is selected so as to engage with a respective selector group track defined by a selector group cam, and an inactive position; when in the non-operating position, the butt retracts so as not to be engaged with the selector set track. Preferably, the selector jack groups are at least partially slidingly arranged in the respective longitudinal needle grooves.

In one aspect, the knitting machine includes: at least one selector device acting later on said selector group according to a control for switching or holding the selector group in the active or inactive position.

In one aspect, the drive chain comprises: and a pusher head sliding between the sub-needle and the selector set, wherein a lower portion of the pusher head engages with the selector set and an upper portion of the pusher head engages with the sub-needle, wherein the pusher head has a respective butt engageable with a respective pusher head race defined by a pusher head cam. Preferably, the pusher heads are slidably arranged in the respective longitudinal needle grooves.

In an aspect, the pusher head track includes a tucker needle raising cam and a knockover needle raising cam for each feeder with reference to a drive chain rotating in a rotational direction about a central axis with respect to the drive cam, and an entrance of the knockover needle raising cam circumferentially precedes an entrance of the tucker needle raising cam.

In one aspect, the selector set track comprises a single track defining a first and a second needle raising cam for each feeder arranged in succession to each other.

In one aspect, the first stitch cam circumferentially precedes the second stitch cam.

In one aspect, the first set-up cam is "operably associated with" the knockover set-up cam, and the second set-up cam is operably associated with the tucker set-up cam.

With reference to the knockover setting cam, the second setting cam, the tucker setting cam, the "operative association" of the first setting cams means that the corresponding knockover setting cams of the first setting cams are close to the same straight line, parallel to the central axis and located on the circumferential surface on which the cams are located, and which is also used for the second setting cam and the corresponding tucker setting cam. In other words, the needles and the corresponding drive chains, when they are close to the first needle raising cam, are also close to the corresponding knockover needle raising cam. The needles and the corresponding drive chains, when they are close to the second needle-raising cam, are also close to the corresponding tucker needle-raising cam. Thus, the selector groups of the drive chains engage with the first tucking cam, the pusher heads of the same drive chains engage or are about to engage with the knockover needle raising cam, and when the selector groups of the drive chains engage with the second tucking cam, the pusher heads of the same drive chains engage or are about to engage with the tucking needle raising cam.

The applicant has found that the present invention allows to solve the problems related to the limitation of the needle movement due to the dimensions of the machine and thus to achieve the desired objects.

In particular, the applicant has found that the invention allows moving the needles to form tucks or loops which limit the circumferential development of the triangles dedicated to these movements.

This feature allows to provide a needle providing more movement and/or to reduce the axial and circumferential movement of the cylinder and the cam with respect to the prior art, the same needle movement being achieved. This allows to make the fabric with a smaller diameter and/or with many characteristics different from each other, and/or to reduce the inertia of the needle cylinder and therefore increase the working speed.

In fact, as will be more easily understood from the following detailed description, the particular shape of the selector group track, the second lift cam (operatively associated with the tucker lift cam) following (i.e. located downstream of) the first lift cam (operatively associated with the knockover lift cam), and the particular shape of the pusher head track, the tucker lift cam following the knockover lift cam, allow to make the needle perform tucking and looping in a limited circumferential space and in a simpler and faster way.

Other aspects of the invention are specified below.

In one aspect, the entry of the knockover needle lift cam is immediately prior to (i.e., located immediately upstream of) the entry of the tucker needle lift cam. By travelling forward with respect to the cams, each needle and the respective drive chain first encounters the entry of the knockover lift cams and then the entry of the tucker lift cams. By "directly before" is meant that there is no other entry or runway between the two noted entries for pushing the butt.

In one aspect, the exit of the knockover needle set-up cam is immediately prior to (i.e., located immediately upstream of) the exit of the tucker needle set-up cam. By "directly before" is meant that there is no other outlet or runway for the pushing butt between the two outlets mentioned.

In one aspect, the yarn feeder follows (i.e. is located downstream) the respective maximum height points of the tucker and drop stitch cams.

In one aspect, the tucker stitch cam and the knockover stitch cam progress parallel or substantially parallel to each other. Preferably, but not necessarily, the knockover setting cam and the tucker setting cam have the same slope.

In one aspect, the entry of the knockover lift cam and the entry of the tucker lift cam diverge from the base track. Preferably, the basic track is at a constant axial height, i.e. it is a circle.

In one aspect, the maximum height of the knockover setting cam is higher than the maximum height of the tucker setting cam.

In one aspect, the axial extension of the knockover setting cam is longer than the axial extension of the tucker setting cam.

In one aspect, the circumferential extension of the knockover setting cam is longer than the circumferential extension of the tucker setting cam.

In one aspect, the length of the knockover setting cam is longer than the length of the tucker setting cam.

In one aspect, the tucker and drop stitch cams coincide with each other after (i.e., downstream of) the respective maximum height point.

In one aspect, the tucker stitch cam is part of a head track, and the knockover stitch tucker stitch cam is part of a drop stitch head track.

In one aspect, the tuck-pushing head runways and drop-stitch-pushing head runways merge after (i.e., downstream of) the respective tuck-needle raising cams and drop-needle raising cams.

In one aspect, the drop stitch push head track has a substantially horizontal length that is after (i.e., downstream of) the knockover stitch lift cam.

In one aspect, the drop stitch push head runway has a knockover stitch drop cam that connects a substantially horizontal length to an exit of the tucker raising cam.

In one aspect, the pusher head racetracks associated with each yarn feeder are symmetrical about the yarn feeder.

In one aspect, the pusher head track includes a first pair of tucker and knockover stitch cams and a second pair of tucker and knockover cams connected to each feeder.

In one aspect, the ramps of the first and second pairs are symmetrically arranged with respect to the yarn feeder.

In one aspect, the tuck-and-drop-stitch cams of the first and second pairs merge into a middle region of the pusher head runway aligned with the respective yarn feeder.

In one aspect, the single track has at least one guard triangle segment having a peak and a valley.

In one aspect, the needle protection cam section includes a first needle raising cam and a second needle raising cam.

In one aspect, the axial extension of the first needle raising cam is substantially the same as the axial extension of the second needle raising cam.

In one aspect, the circumferential extension of the first stitch cam is substantially the same as the circumferential extension of the second stitch cam.

In one aspect, the first and second set-up cams progress substantially parallel to each other.

In one aspect, the knockover stitch cams are circumferentially offset relative to the respective first lift cams.

In one aspect, the tucker raising cam is circumferentially offset relative to the second raising cam.

In one aspect, the first lift cam is circumferentially forward relative to the knockover lift cam.

In one aspect, the maximum height of the first lift cam is circumferentially ahead of the entry of the corresponding knockover lift cam.

In one aspect, the second set-up cam is circumferentially forward relative to the tucker set-up cam.

In one aspect, the base of the second needle raising cam precedes the entrance of the respective tucker needle raising cam in the circumferential direction.

In one aspect, the maximum height of the second set-up cam precedes the maximum height of the respective tucker set-up cam in the circumferential direction.

In one aspect, the entry point of the butt of the selector plate group in the needle guard triangle section is defined at the valley of the needle guard triangle section.

In one aspect, the needle protection cam section comprises a first needle lowering cam, wherein the first needle lowering cam is between the first needle raising cam and the second needle raising cam.

In one aspect, the needle protection cam section comprises a second needle lowering cam following (i.e., located downstream of) a second needle raising cam. The butt of the selector group can thus slide in a single trajectory, passing in a continuous manner through the first raising cam, the first drop cam, the second raising cam and the second drop cam.

In one aspect, the entry point of the butt of the selector jack group at the needle protection cam section is defined on the bottom of the first needle raising cam and on the bottom of the second needle raising cam.

In one aspect, a first needle raising point of the butt of the selector jack group in the needle protection triangle section is defined on the bottom of the first needle raising cam.

In one aspect, a second needle raising point of the butt of the selector jack group in the needle protection cam section is defined on the bottom of the second needle raising cam.

In one aspect, a single track has a non-controlled zone for each yarn feeder and is configured to radially separate the respective butt from the single track. As a result, the butts of the axial oscillation elements of the selector group leave the single trajectory and enter the longitudinal needle groove of the needle-holding needle cylinder housing the drive chain.

In one aspect, the yarn feeders are located in respective non-control zones.

In one aspect, the non-control zone follows (i.e., is located downstream of) the second descending cam.

In one aspect, the non-control zone has at least one exit ramp, a chamfered ramp defining and extending between a bottom surface and a radially outer side surface of the single track. The butt of the selector group moves forward into the outlet area up to the outlet ramp and slides on said ramp and then moves radially inwards.

In one aspect, the non-control zone is symmetrical with respect to the respective yarn feeder.

In one aspect, the non-control zone has two exit ramps at opposite ends.

In one aspect, the single track includes guard triangle segments disposed on both sides of the non-control zone.

In one aspect, the knitting machine comprises at least two yarn feeders.

In one aspect, the single track comprises a non-control zone associated with each yarn feeder and at least two needle-guard triangular segments, each needle-guard triangular segment being located between two non-control zones that are circumferentially consecutive to each other. .

In one aspect, the needle protection cam section is symmetrical with respect to an intermediate axial straight line located in the middle between two yarn feeders successive in the circumferential direction.

In one aspect, the needle shield triangle section includes a needle-raising middle high point, which is preferably linearly symmetrical about a middle axis.

In one aspect, the needle protection cam section includes two side high points disposed on either side of the needle-raising middle high point, one side projection being located on one side of the needle-raising middle high point.

In one aspect, there are two valleys, each defined between a raised middle high point and each side bump.

In one aspect, the needle-raising middle high point has two sides, wherein a first side of the two sides is defined as a first needle-raising triangle and a second side of the two sides is defined as a first needle-lowering triangle with reference to a drive chain rotating in a counterclockwise direction about a central axis with respect to the drive triangle, wherein the first needle-raising triangle and the first needle-lowering triangle operate for the first yarn feeder.

In one aspect, with reference to a drive chain rotating in a clockwise direction about a central axis relative to the drive cams, a second of the two sides defines a first stitch cam and a first of the two sides defines a first drop cam, wherein the first stitch cam and the first drop cam operate for a second yarn feeder adjacent to the first yarn feeder.

In one aspect, one of the two high points defines a second needle raising cam and a second needle lowering cam, which operate for the first yarn feeder, with reference to a drive chain rotating in a clockwise direction about a central axis relative to the drive cam.

In one aspect, with reference to a drive chain rotating in a counterclockwise direction about a central axis with respect to the drive cam, the other of the two side high points defines a second needle raising cam and a second needle lowering cam operating for a second yarn feeder adjacent to the first yarn feeder.

The needle-protection triangle located between two adjacent feeders works for the feeder, which follows (i.e. is arranged downstream) the needle-protection triangle with respect to the movement of the needle and the drive chain, which slide with respect to the triangle due to the rotation of the needle-holding needle cylinder in the predetermined direction. When the direction of rotation is reversed, the direction of movement of the needle and the drive train relative to the triangle is also reversed, and the same needle guard triangle segment operates for the other yarn feeder.

In one aspect, at least one needle selection device is located between two successive feeders.

In one aspect, the knitting machine comprises at least two feeders and at least two selection devices, each selection device being located between two successive feeders.

In one aspect, the at least one needle selection device is located at a respective needle guard triangle section.

In one aspect, the needle selection apparatus includes two drivers arranged side by side with each other in the circumferential direction.

In one aspect, two drivers are located between two consecutive yarn feeders.

In one aspect, each driver is located at a respective valley (or valley) defined by the guard triangle segment, preferably between each side bump at the mid-needle high point.

In one aspect, the driver is of a magnetic or piezoelectric type.

In one aspect, the driver is of the selector blade bit type.

In one aspect, the driver includes a plurality of selector blade bits.

In one aspect, each selector blade head is movable between a first position and a second position in accordance with a control, and preferably each selector blade head is movable longitudinally between a raised position and a lowered position in accordance with a control.

In one aspect, the driver includes a plurality of selector blade heads, each of which oscillates about a horizontal axis in accordance with the control.

In one aspect, the selector blade head driver (selector head) includes a first set of selector blades and a second set of selector blades.

In one aspect, each selector knife comprises a plurality of selector blade heads arranged successively to each other along a common axis, preferably overlapping and aligned along a vertical line.

In one aspect, the second set of needle selection knives and the first set of needle selection knives are arranged consecutively to each other along a common axis, preferably the second set of needle selection knives is axially positioned above the first set of needle selection knives.

In one aspect, the first set of selection knives is configured to operate, i.e. engage with the teeth of the selector group of the circular knitting machine, if the rotation of the needle-holding needle cylinder with respect to the drive triangle takes place in a first direction of rotation, preferably in a counterclockwise direction.

In one aspect, the second set of selection knives is configured to operate, i.e. engage with the teeth of the selector group, if the rotation of the needle-holding cylinder with respect to the drive triangle takes place in a second direction of rotation, preferably in a clockwise direction.

In one aspect, the selector blade tips of the first set of selector blades are symmetrical to the selector blade tips of the second set of selector blades with reference to a plane of symmetry in which the common axes lie.

In one aspect, each selector blade head is symmetrical about a vertical axis.

In one aspect, the selector blade tips of the first set of selector blades are symmetrical to the selector blade tips of the second set of selector blades.

In one aspect, the selector blade tips of the first set of selector blades are all movable together.

In one aspect, the selector blade heads of the selector knives of the first group are movable about respective axes orthogonal to the common axis, preferably about respective horizontal axes.

In one aspect, the selector blade heads of the second set of selector blades are all movable together.

In one aspect, the selector blade heads of the second set of selector knives are movable about respective axes orthogonal to the common axis, preferably about respective horizontal axes.

In an aspect, the first set of needle selection blades and the second set of needle selection blades are movable independently of each other.

In one aspect, the selector blade heads of the first set of selector blades are movable independently of the selector blade heads of the second set of selector blades.

In one aspect, the selector blade tips of the first set of selector blades have corresponding first engagement surfaces for the teeth of the selector blade set.

In one aspect, the selector blade heads of the second set of selector blades have corresponding second engagement surfaces for the teeth of the selector blade set.

In one aspect, the first engagement surface and the second engagement surface are inclined in opposite directions.

In one aspect, the first engagement surfaces lie in a first common plane that is inclined relative to the plane of symmetry or a first plane that is inclined relative to the plane of symmetry.

In one aspect, the second engagement surfaces lie in a second common plane that is inclined relative to the plane of symmetry, or a second plane that is inclined relative to the plane of symmetry.

In one aspect, the first and second engagement surfaces are inclined in opposite (opposite) directions of the plane of symmetry.

In a separate aspect, the invention relates to a selector blade head driver (selector head) for a circular knitting machine according to one or more of the above-mentioned aspects, wherein the driver can be used in the knitting machine described and claimed herein, as well as in other circular knitting machines, preferably with varying rotary motion.

In a separate aspect, the invention also relates to a circular knitting machine, preferably with a variable rotational movement, comprising at least one drive according to one or more of the aspects described above.

In a separate aspect, the invention also relates to a circular knitting machine, preferably with a variable rotary motion, comprising: a needle-holding cylinder having a plurality of longitudinal needle slots arranged around a central axis of the needle-holding cylinder; a plurality of needles, each needle received in a respective longitudinal needle slot; at least one yarn feeder operatively associated with the needle; a drive cam arranged around the needle-holding cylinder and movable relative to the needle-holding cylinder about a central axis for inducing or allowing a movement of the needle along a longitudinal needle slot such that a stitch formation is effected by the needle; a drive chain for each needle, which is inserted in the respective longitudinal needle slot, is located below the respective needle, and which is operatively placed between the respective needle and the drive triangle;

wherein the drive chain comprises: a selector group, arranged below the auxiliary needle, having at least one respective butt radially movable between an active position, in which it is selected so as to engage with a respective selector group track defined by a selector group cam, and an inactive position; when in the non-operating position, the butt retracts so as not to be engaged with the selector set track.

In one aspect, the machine comprises at least one selector device for switching or holding a selector group in the active position or in the inactive position, depending on the action on said selector group.

Wherein the needle selection device comprises a drive according to at least one of the above aspects.

In one aspect, the selector knives of the first set of each of the two drives are configured to mesh with the teeth of the selector set if the rotation of the needle-holding cylinder with respect to the drive cam takes place in a first direction of rotation, i.e. in the counterclockwise direction.

In one aspect, the second set of selector knives of each of the two drives is configured to engage with the teeth of the selector group if the rotation of the needle-holding cylinder with respect to the drive cam takes place in a second direction of rotation, opposite to the first direction of rotation, i.e. in the clockwise direction.

The applicant has found that the actuator according to the invention, which comprises selector blade heads that can operate both in a clockwise direction and in a counter-clockwise direction, allows a further reduction in the dimensions of the machine, since the space required between the two feeds for mounting the actuator acting on the selector blade group is smaller.

In one aspect, the invention relates to a method for moving a circular knitting machine, wherein the knitting machine is manufactured according to one or more of the aspects described above and/or in the appended claims.

In one aspect, the method comprises: causing relative rotation between the needle-holding cylinder and the drive cam.

In one aspect, the method comprises:

clamping a butt of the needle selecting set into a first needle starting point arranged at the bottom of a first needle starting triangle;

lifting the selector jack set by said relative rotation and subsequent sliding of the corresponding butt on the first lifting cam;

the pushing head is lifted by the axial upward thrust formed by the needle selecting sheet set until the butt of the pushing head is clamped with the needle raising cam of the knocking over needle;

further raising the pusher head by said relative rotation and subsequent sliding of the corresponding butt on the knockover stitch raising cam, so as to raise the needle and form the drop stitch;

the pushing head leaves the needle selecting sheet group when being lifted;

wherein, when the pusher is lifted and slides on the knockover needle raising cam, the butt of the selector set moves in a single trajectory, also passing the second needle raising cam.

In one aspect, the method comprises: :

clamping the butt of the needle selecting set into a second needle raising point arranged at the bottom of a second needle raising cam;

lifting the selector set by said relative rotation and subsequent sliding of the corresponding butt on the second raising cam;

the pushing head is lifted by the axial upward thrust formed by the needle selecting set until the butt of the pushing head is clamped with the tucking needle raising cam;

the pusher head is further lifted by said relative rotation and the subsequent sliding of the corresponding butt on the tucker raising cam, so as to lift the needle and form the tuck.

On the one hand, after the second needle raising cam is walked, the butt of the selector group walks by the second needle lowering cam and enters the non-control area.

In one aspect, the butts of the selector group pass through the non-control zone until they come into abutment with the exit ramp, which causes the respective butts to leave the single trajectory radially. The butt approaches the rotation axis radially and returns into the corresponding needle slot of the needle-holding cylinder containing the drive chain.

On the one hand, if the needle-holding cylinder rotates in a counterclockwise direction with respect to the actuation cam, the butt of the selector group slides on the first side of the middle high point of the raising in order to lift the pusher until the butt of the pusher engages in the knockover raising cam associated with the first yarn feeder, or the butt of the selector group slides on the first side of the one-side projection in order to lift the pusher until the butt of the pusher engages in the tucker raising cam associated with the first yarn feeder.

On the one hand, if the needle-holding cylinder rotates in a clockwise direction with respect to the actuation cam, the butt of the selector group slides on the second side of the middle high point of the raising in order to lift the pusher until the butt of the pusher engages in the knockover raising cam associated with the second yarn feeder, or the butt of the selector group slides on the second side of said one lateral protuberance in order to lift the pusher until the butt of the pusher engages in the tucker raising cam associated with the second yarn feeder.

In one aspect, the method comprises the (cartridge) selection device acting on the selector group to move or hold the respective butt to or in the active or inactive position.

On the one hand, if the relative rotation of the needle-holding cylinder with respect to the drive cam takes place in a first direction of rotation, preferably in the counterclockwise direction, the first set of selector knives of the at least one drive mesh with the teeth of the selector set.

On the one hand, if the relative rotation of the needle-holding cylinder with respect to the drive cam takes place in a second direction of rotation, preferably in the clockwise direction, the second set of selector knives of the at least one drive mesh with the teeth of the selector set.

On the one hand, if the needle-holding needle cylinder is rotated in a first rotational direction, preferably in an anticlockwise direction, relative to the drive cam, the first drive acts on the selector group for engaging the butt into the first starting point and forming a drop stitch at the yarn feeder, and the second drive acts on the selector group for engaging the butt not previously engaged with the first drive into the second starting point and forming a tuck at said yarn feeder.

On the one hand, if the needle-holding needle cylinder is rotated in a first rotational direction, preferably in the counterclockwise direction, relative to the drive cam, the first group of selector knives of the first drive act on the selector blade set for engaging the butt into the first pick-up point and forming a miss-stitch at the yarn feeder, and the first group of selector knives of the second drive act on the selector blade set for engaging the butt into the second pick-up point and forming a tuck at the yarn feeder.

On the one hand, if the needle-holding cylinder is rotated in a second direction of rotation, preferably in a clockwise direction, relative to the drive cam, the second drive acts on the selector plate set for engaging the butt into the second set-up point and forming a miss-stitch at the different adjacent yarn feeder, and the first drive acts on the selector plate set for engaging the butt not previously engaged with the second drive into the first set-up point and forming a tuck at the different adjacent yarn feeder.

On the one hand, if the needle-holding cylinder is rotated in a second direction of rotation, preferably in a clockwise direction, relative to the drive cam, the second set of selection knives of the second drive act on the selector set for engaging the butt into the second set-up point and forming a miss-stitch at the different adjacent yarn feeder, and the second set of selection knives of the first drive act on the selector set for engaging the butt into the first set-up point and forming a tuck at the different adjacent yarn feeder.

In one aspect, the sub-needle has a butt that is radially movable between an active position, in which it is selected to engage with a corresponding sub-track defined by the sub-needle cam and cause the actuation of the needle and the formation of the stitch, and an inactive position, in which it is retracted so as not to engage with said sub-track.

In one aspect, the drive chain comprises: a driving element, which is slidingly arranged in a respective longitudinal needle groove between the sub-needle and the selector group, wherein the driving element is movable in the height direction with respect to the pusher head and the sub-needle and is operatively engageable with the sub-needle in order to shift and retain the butt of the sub-needle in a respective active position.

In particular, the applicant has found that said driving element, which is freely movable with respect to the pusher head and the sub-needle, allows to determine where and when the radial extraction/insertion takes place, irrespective of the axial position of the pusher head and/or of the selector group.

In other words, the pusher head pushes the sub-needle and the needle upwards without having to cause the radially moving butt of the sub-needle to switch each time from the inactive position to the active position, since this switching is caused by the driving element.

Moreover, for example, the needle can be moved to a higher lever in the inactive position, in order to perform the transfer position without having to move lower elements, such as in particular the selector group and/or the pusher head.

The solution according to the invention, which allows to control the extraction of the butt, is particularly effective during the formation of the coil, regardless of the axial position of the pusher head and/or of the selector group. By "stitch formation" is meant the working phase in which the needle catches the new yarn and pulls it down until the old stitch (previously formed) as a result of the needle drop passes under the needle head, causing a fully formed loop.

In one aspect of the invention, the butt of the sub-needle is transferred to and maintained in said active position during the needle descent, in particular during the needle descent phase in which the stitch forms correspondingly.

In one aspect, the sub-needle, pusher head, selector set and drive element are flat plate members. The drive chain is known as a "catenary" and is made of the above-mentioned plate part which is slidably inserted into the longitudinal needle groove.

In one aspect, the drive chain is configured for decoupling the axial movement of the needle and/or sub-needle from the axial movement of the pusher head and/or the drive element and/or the selector jack set.

In one aspect, the drive chain is configured for decoupling axial movement of the drive element from axial movement of the pusher head and/or the needle and/or the selector set.

In one aspect, the drive chain is configured for decoupling the axial movement of the pusher head and/or the selector group from the drive/stop of the radially moving butt of the sub-needle.

In one aspect, the sub-needle and the needle are integrally formed.

In a different aspect, the sub-needle and the needle are separate elements.

In one aspect, the upper end of the sub-needle engages with the needle, preferably by two-sided and/or hinged restraining engagement.

In one aspect, the sub-needle comprises a support with a respective butt.

In one aspect, the drive element is operably engaged with the support.

In one aspect, the support is elastically movable between a first configuration, corresponding to the active position of the butt, and a second configuration, corresponding to the inactive position of the butt.

The applicant has also found that the elastic drive allows moving the butt of the sub-needle (non-working needle) in a more efficient and safer way with respect to the known movements obtained by oscillating the hard element and/or by rotating the whole needle and/or sub-needle.

In one aspect, the support portion applies an elastic restoring force to the butt in the inactive position of said butt

In one aspect, in the inactive position of the butts, the elastic force keeps the support and the respective butt in the respective needle groove.

The applicant has also found that the elastic restoring force ensures the radially retracted rest position in a safe and effective manner.

In one aspect, against said elastic force, the drive element switches and holds the butt to the respective active position.

In other words, the butt remains in the inactive position due to the elastic restoring force when it is not engaged or pressed by the drive element, only actively moved towards the active position by the drive element.

In one aspect, the support portion comprises a resilient rod extending, preferably projecting, towards the drive element. The elastic force is given by the elastic rod.

In one aspect, the resilient lever is in the needle slot.

In one aspect, the resilient rod extends substantially parallel to the axial direction.

In one aspect, the sub-needle includes a body from which the resilient stem extends and protrudes.

In one aspect, the support portion includes a lower portion at a distal end of the resilient lever, wherein the lower portion carries a butt of the sub-needle.

In one aspect, the sub-needle comprises a retaining element located in a radially outer position with respect to said lower portion, so as to limit the radial stroke of the butt of the sub-needle.

In one aspect, a retaining element defined by the axial extension of the sub-needle is formed from the body and is preferably substantially parallel to the elastic rod.

At rest, the elasticity of the elastic rod of the sub-needle keeps the radially moving butt in the inactive position, thus making the needle inoperative. The butt of the sub-needle must be driven to form the stitch by the needle. The butt is therefore not free but remains inside or outside the needle groove.

In one aspect, the sub-needle includes a sub-butt.

In one aspect, the auxiliary butt extends radially from the body of the auxiliary needle.

In one aspect, the sub-needle cam defines a sub-needle track, and the sub-butt of the sub-needle is engageable with the sub-needle track.

In one aspect, the sub-needle has a contact surface directed axially toward the pusher head.

In one aspect, the contact surface is located near an upper end of the sub-needle.

In one aspect, the pusher head extends at least partially parallel and at a radially more inward position with respect to the drive element and the sub-needle.

In one aspect, the headrest is pushed against a bottom surface of the respective needle slot.

In one aspect, the drive element and the sub-needle bear radially against the pusher head.

In one aspect, the pushing head includes an elongated, preferably rod-shaped upper portion, and a lower portion or foot at the lower end of the elongated portion.

In one aspect, the drive element and the sub-needle bear radially against the elongate portion.

In one aspect, in the second configuration of the support, said support radially and at least partially abuts against the push head, preferably against the elongated portion of the push head.

In one aspect, the lower portion of the pusher head has a contact surface directed toward the drive element.

In one aspect, the upper portion of the pusher head, preferably the distal end of the elongated upper portion, can engage the contact surface of the sub-needle, preferably with a unilateral axial rest.

In the context of the present invention, the term "unilateral axial rest" means a mechanical connection or constraint between two elements, in which the thrust of a first element on the axis of a second element, together with the movement of the first element towards the second element, causes a corresponding movement of the second element (integrally with the first element), whereas the movement of the first element away from the second element causes the separation of the two elements without having to remove the second element, and vice versa. In other words, this constraint is maintained by means of contact between the two elements when the first element is moved towards the second element, whereas it can be cancelled when the first element is moved in the opposite direction with respect to the second element, in which case the two elements are separated.

On the one hand, the lower part of the pusher head, preferably facing the selector group contact surface, can engage with said selector group, in particular by one-sided axial resting.

In one aspect, the butt of the pusher head extends radially from a lower portion of said pusher head.

In one aspect, the drive element has an upper end preferably having an inclined surface. Said upper end, preferably said inclined surface, cooperates with the lower portion of the support in order to switch the butt of the sub-needle to the respective active position against the elastic force exerted by the support. .

In one aspect, the inclined surface is directed radially outward.

In one aspect, the lower portion of the support portion has an inclined surface facing the upper end of the drive element and configured to cooperate with the inclined surface of the drive element.

In one aspect, the driving element has a tip configured for receiving at least a portion of said lower portion and holding the butt of the sub-needle in the respective active position and/or axially pushing against the sub-needle.

In one aspect, the tip is located at the upper end of the drive element and is preferably the inverse of the lower portion of the support.

In one aspect, the tip is formed in a continuous manner from the inclined surface of the drive element.

In one aspect, the drive element has a lower end that can engage the contact surface of the pusher head, preferably with a unilateral axial rest.

In one aspect, the drive element has a corresponding butt.

In one aspect, the drive element cam defines a drive element track, and the butt of the drive element is engageable with the drive element track.

In one aspect, the butt of the drive element extends radially from an axially intermediate region of the drive element.

In one aspect, the selector group comprises an axial oscillation element slidingly arranged in a respective longitudinal needle groove.

On the one hand, the axial oscillation elements of the selector group carry respective butts.

In one aspect, the selector jack set has an auxiliary butt.

On the one hand, the axial oscillation element of the selector group carries a corresponding auxiliary butt.

In one aspect, the auxiliary drive selector group cam defines an auxiliary selector group course, and the auxiliary butt of the selector group is engageable with the auxiliary selector group diameter.

In one aspect, the selector group comprises axial fixing elements engageable by the selection device, wherein the axial fixing elements are operatively engaged by the axial oscillating elements so as to radially move the respective butt and the auxiliary butt (if present) in the active position and in the inactive position.

On the one hand, the axial fixing element is oscillated by the influence of the needle selection device.

In one aspect, the axial swinging element swings under the influence of the axial fixing element.

In one aspect, the axial securing element includes a plurality of radially outwardly facing teeth that are selectively engageable with the needle selection device.

On the one hand, the axial fixing element is not present and the selection device, preferably of the magnetic type, acts directly on the axial oscillating element.

On the one hand, the auxiliary butt of the sub-needle, the butt of the pusher head and the butt of the driving element move in the axial direction and are fixed in the radial direction.

On the one hand, the butt of the selector group and the auxiliary butt of the selector group move in the axial direction and also move in the radial direction.

In one aspect, the maximum stroke of the sub-needle and of the needle is longer than the maximum stroke of the pusher head when the radially moving butt is in the inactive position.

In one aspect, the maximum stroke of the sub-needle and the needle when the radially moving butt is in the active position is shorter than the maximum stroke of the sub-needle and the needle when the radially moving butt is in the inactive position.

In one aspect, the maximum stroke of the pusher is longer than the maximum stroke of the axial oscillation element of the selector group.

On the one hand, the maximum stroke of the sub-needle and of the needle is three times the maximum stroke of the axial oscillation element of the selector group when the radially moving butt is in the inactive position.

In one aspect, the maximum stroke of the sub-needle and of the needle is approximately 1,2 times the maximum stroke of the pusher head when the radially moving butt is in the inactive position.

In one aspect, the needle-holding cylinder has a reference diameter, less than about 200mm, preferably less than about 100 mm. By "reference diameter" is meant the diameter measured on the bottom surface of the axial needle groove defined on the outer surface of the cylinder, in which the needle is slidingly housed. In the technical field of circular knitting machines, the bottom surface of the needle groove is called the bottom surface; the reference diameter is thus determined from the bottom surface.

In one aspect, the circular machine has a plurality of feed points (lanes) of more than one, or preferably more than two, or preferably four or more.

In one aspect, the present invention relates to a method for moving needles of a circular knitting machine, wherein the knitting machine is preferably manufactured according to one or more of the above aspects and/or one or more of the appended claims and/or embodiments.

The method for moving the needles of a circular knitting machine comprises radially moving the heels of the sub-needles engaged with the respective needles between an active position, in which the heels are selected so as to engage with the respective sub-needle tracks defined by the sub-needle cams and cause the actuation of the needles and the formation of stitches, and an inactive position, in which the heels are retracted so as not to engage with said sub-needle tracks; wherein the radial movement of the butt of the sub-needle is caused by a corresponding axial movement between the sub-needle and a drive element axially below the sub-needle; wherein said corresponding axial movement is at least in some steps decoupled/independent from the axial movement of the pusher head and/or the selector group, which is arranged below the needle and is operatively driven by a selection device acting upon said selector group upon control.

In one aspect, during the relative movement between the sub-needle and the drive element, the upper end of the drive element, preferably the inclined surface, cooperates with the support of the butt of the sub-needle.

In one aspect, a substantially radial elastic force acts on the support of the butt of the sub-needle in order to keep the butt in the inactive position.

In one aspect, the upper end of the drive element acts against the spring force during movement from the inoperative position to the operative position.

On the one hand, during the movement from the inactive position to the active position, the upper end of the drive element is inserted between the needle-holding cylinder and the support of the butt of the sub-needle (in particular, it is inserted between the upper portion of the butt and the support of the butt of the sub-needle).

In one aspect, the elastic force restores the butt from the active position to the inactive position.

In one aspect, in the step of radially moving the butt of the sub-needle, said butt is transferred to or maintained in said active position during the lowering of the needle, in particular during the lowering step corresponding to the formation of the stitch.

In one aspect, the pusher head pushes the drive element axially upwards until the butt of the drive element engages with the (drive element triangle) drive element triangle, and then the pusher head leaves the drive element.

In one aspect, a pusher head cam, with which a butt of the pusher head engages, guides the pusher head axially upward or downward.

In one aspect, the sub-needle cams, with which the sub-butts of the sub-needles engage, guide said sub-needles axially downwards, while the driving element cams, with which the butts of the driving elements engage, guide the driving elements upwards until the upper ends of the driving elements are inserted between the needle-holding cylinder and the support of the butts of the sub-needles.

In one aspect, the sub-needle cam with which the sub-butt of the sub-needle engages axially guides the sub-needle upwards, while the driving element cam guides the driving element downwards until the upper end of the driving element is extracted from below the support of the sub-butt.

In one aspect, the pusher head pushes directly against the sub-needle so as to guide it upwards.

On the one hand, the selector group, preferably the axial oscillation element of the selector group, pushes the pusher axially upwards until the butt of the pusher engages with the pusher cam and then leaves the pusher.

In one aspect, a selector group cam with which a butt of a selector group engages, and/or an assist-driven selector group cam with which an assist butt of a selector group engages, axially guides the selector group upward or downward.

On the one hand, the axial fixing element of the selector group radially pushes the axial oscillation element of the selector group in order to oscillate it and cause a radial movement of the corresponding butt and, if present, of the auxiliary butt.

On the one hand, the selector device acts against the axial fixing element of the selector group, so as to oscillate it and radially push the axial oscillation element.

In one aspect, the maximum axial stroke of the axial oscillation element of the selector group is smaller than the maximum axial stroke of the needle and/or of the sub-needle, and/or of the drive element, and/or of the pusher head.

Further characteristics and advantages of the invention will become clearer from the detailed description of a preferred embodiment of a circular knitting machine and of a method for moving needles according to the invention.

Drawings

The present description is described below for illustrative and therefore non-limiting purposes, with reference to the accompanying drawings, in which: :

figure 1 shows a partially enlarged view of the needle-holding needle cylinder of the circular knitting machine according to the invention, in which the drive chain of the needles is visible, plus a segment of the drive triangle in the form of a plane;

figures 2a and 2b show respective partial enlarged views of the drive chain plus the needle;

figure 2c shows a variation of the elements of the drive chain;

figures 3 a-3 i and 3l-3t show a series of possible configurations of the drive chain;

4a-4d show a section of the drive cam, in the same plane, of the runway on which the drive cam engages the drive chain;

figure 5a shows an enlarged portion of the drive triangle in a counter-clockwise rotation operation;

figure 5b shows a portion of figure 5a when the triangle is operated with a counter-clockwise rotation;

figure 6 shows a perspective view of a detail of the triangle of figures 5a and 5 b;

figure 7 shows a perspective view of the drive used in the knitting machine of the preceding figures;

fig. 8 shows a top view of the actuator of fig. 7.

Detailed Description

With reference to the figures, number 1 globally designates the head of the circular knitting machine of the invention.

The circular knitting machine comprises a base, not shown as it is known, which constitutes the support structure of the machine and on which the head 1 is mounted.

The knitting head 1 is equipped with a needle-holding cylinder 2, with a plurality of needles 3 mounted on the needle-holding cylinder 2, and with control means apt to selectively actuate said needles 3 to carry out the production of the fabric.

The needle-holding cylinder 2 is mounted in a vertical position on the base in a row, the needles 3 being arranged vertically and protruding over the upper edge of the needle-holding cylinder 2.

For example, the needle-holding cylinder 2 has a reference diameter of about 100mm and a height of about 450 mm.

As shown in fig. 1, the needle-holding cylinder 2 has a plurality of longitudinal needle grooves 4 arranged on the radially outer surface of the needle-holding cylinder 2. The longitudinal needle grooves 4 are arranged around and parallel to a central axis "X-X" (vertical) of the needle-holding needle cylinder 2. Each longitudinal needle channel 4 accommodates a respective 3 and a respective drive chain 5 or "catenary wire" comprising a plurality of plate sections. The drive cams "C" are arranged around the cam bodies of the needle-holding cylinder 2 and are located facing the radially outer surface of the needle-holding cylinder 2 and thus the longitudinal needle slots 4 drive the chain 5. These drive triangles "C" are formed by plates and/or needle grooves arranged on the inner surface of the triangle base.

For the sake of clarity, in fig. 1, the length of these drive triangles "C" appears to run in a plane and beside the drive chain 5 and one needle 3.

In the embodiment shown, the triangle seats of the drive triangle "C" are substantially fixed, while the needle-holding cylinder 2 rotates (in a continuous or varying movement in both directions) around the central axis "X-X" so as to generate a relative rotational movement between the drive chain 5 and the drive triangle "C".

As will be explained in more detail below, the drive chain 5 can be operatively connected to a drive triangle "C" in order to transform said relative rotational movement into an axial movement of the needle 3 along the longitudinal needle groove 4, so as to achieve the formation of a stitch by said needle 3. The actuation cam "C" defines a track extending around the needle-holding needle cylinder 2, which is/can be engaged by a butt belonging to the actuation chain 5. Thus, each drive chain 5 is operatively located between a respective needle 3 and the drive triangle "C".

A suitable device, not illustrated, feeds the knitting yarn at one or more feed points (known as passes) usually arranged above the needle-holding needle cylinder 2. For example, the circular machine shown has four feed points.

As shown in figures 1, 2a and 2b, the relative positions of the various elements will now be described with reference to a single drive chain 5 to which the respective needle 3 is connected, said respective needle 3 being correctly mounted in the vertical direction on the needle-holding cylinder 2.

The needles 3 are arranged at the upper edge of the needle-holding cylinder 2 and the drive chain 5 is arranged below the needles 3 up to near the bottom of the needle-holding cylinder 2.

As can be better seen from fig. 2a and 2b, the drive chain 5 comprises an auxiliary needle 6 disposed immediately below the needle 3, a pusher head 7 arranged locally below the auxiliary needle 6, a drive element 8 radially outside the pusher head 7 and below the auxiliary needle 6, and a selector group 9 below the pusher head 7.

The needle 3 has a hook-shaped foot 10. When the needle 3 is correctly positioned in the longitudinal needle groove 4, the foot 10 is oriented radially outwards.

The sub-needle 6 has a body 11. The upper end 12 of the body 11 has a butt 13 and a projection 14 located below the butt 13. The projection 14 has an upper face 15 formed in a continuous manner from the butt 13 and an opposite lower contact face 16. When the sub-needle 6 is correctly positioned in the longitudinal needle groove 4, the butt 13 projection 14 is directed radially towards the inside of said needle groove 4.

The needle 3 is firmly connected to the sub-needle 6 by inserting the foot 10 into the butt 13. The connection of the foot 10 and the butt 13 is bilateral, i.e. the needle 3 and the sub-needle 6 move as a whole along the longitudinal needle groove 4. Since the needle 3 and the sub-needle 6 are united with each other in their vertical axial movement, the connection of the foot 10 to the butt 13 constitutes a kind of hinge, but can slightly oscillate with respect to each other in the interconnection. The hinge is moved along the longitudinal needle groove 4 based on the axial movement of the needle 3 and the sub-needle 6 unified with each other. The foot 10 can be easily connected to or disconnected from the butt 13 in order to assemble or disassemble the two elements.

In a different embodiment, not shown, the sub-needle and the needle are made in one piece.

The resilient rod 17 extends from the body 11 and is directed axially downwards, i.e. towards the drive element 8. The lower portion 18, located at the distal end of the elastic rod 17, carries a radially mobile butt 19 of the sub-needle 6. The lower portion 18 terminates with a sub-needle trailing end 20, the sub-needle trailing end 20 being rounded and/or having a sloping surface. The elastic rod 17 and the lower portion 18 constitute an elastic movement support portion that moves the butt 19 in the radial direction.

An axially extending portion 21 is formed downwardly from the body 11 and is parallel to the central axis "X-X". The axial extension 21 is located at a radially outer position with respect to the flexible arm 17 and is substantially parallel to said flexible arm 17. The length of the axial extension 21 is less than the entire length of the

supports

17, 18, so that the radially mobile butt 19 remains below the end of said axial extension 21. As will be better apparent hereinafter, this axial extension 21 constitutes a retaining element of the radial stroke of the butt 19 of the sub-needle 6. In fact, the elastic flexibility of the elastic rod 17 allows the lower portion 18 and the butt 19 to move, when subjected to external stresses, along a substantially radial track between an active position, in which the butt 19 protrudes from the longitudinal needle groove 4, and an inactive position, in which the butt 19 is retracted into the longitudinal needle groove 4. In the extended position, the lower portion 18 abuts the axial extension 21. In both positions, the elastic rod 17 is located in the needle groove 4 (only the butt 19 is raised radially from said needle groove 4 in the extended position).

The

support

17, 18 as a whole is therefore elastically movable between a first configuration, corresponding to the active position of the butt 19, and a second configuration, corresponding to the inactive position of the butt 19.

The sub-needle 6 also comprises an auxiliary butt 22 extending radially from the body 11 of the sub-needle 6. In the embodiment shown, this auxiliary butt 22 is connected to the body 11 at the root of the axial extension 21.

The pusher head 7 comprises: an elongated rod-like upper portion 23 and a lower portion 24 or foot at the lower end of the elongated portion 23. The lower part 24 carries respective butts 25 formed radially and has an upper contact surface 26 facing upwards, i.e. towards the sub-needle 6 and towards the driving element 8, and a lower contact surface 27 facing downwards, i.e. towards the selector group 9.

Like the position of the corresponding butt 25, the pusher head 7 rests against the bottom surface of the longitudinal needle groove 4 and its radial position is fixed, while said pusher head 7 is able to slide axially in said needle groove 4.

The body 11 of the sub-needle 6 is in a radially outer position with respect to the elongated upper portion 23 of the pusher head 7 and rests radially all the way on said elongated upper portion 23. The projection 14 of the sub-needle 6 abuts against the bottom surface of the longitudinal needle groove 4 and the distal end 28 of the elongated upper portion 23 of the pusher head 7 is still located below the projection 14 and faces the lower contact surface 16 of said projection 14.

Said distal end 28 can abut against the contact surface 16 of the sub-needle 6 by means of a unilateral axial rest.

The elastic action exerted by the elastic rod 17 pushes the lower portion 18 radially towards the elongated upper portion 23. In the configuration shown in figures 1, 2a and 2b, the elastic rod 17 keeps the lower portion 18 against the elongated upper portion 23. In other words, in the inactive position of said butt 19, the

supports

17, 18 exert an elastic return force on the butt 19, and in said inactive position, said elastic force keeps the

supports

17, 18 and the respective butt 19 inside the needle groove 4.

The driving element 8 also bears radially against the elongated upper portion 23 and is axially located between the sub-needle 6 and the lower portion 24 of the pusher head 7.

The drive element 8 has an upper end provided with an inclined surface 29, said inclined surface 29 facing radially outwards and axially upwards, i.e. towards the sub-needle 6. In other words, the inclined surface 29 gradually approaches the distal end 28 as it ascends toward the sub-needle 6.

The inclined surface 29 cooperates with the sub-needle tail end 20 of the

support

17, 18 to transfer the butt 19 of the sub-needle 6 to the respective active position against the elastic force exerted by the

support

17, 18. From a dynamic point of view, the coupling between the inclined surface 29 and the sub-needle tail 20 constitutes a plate cam, in which the raising of the inclined surface 29 causes a radial rotation of the butt 19 towards the outside of the cylinder (i.e. towards the outside of the needle groove 4) in order to transfer the butt 19 to the respective active position.

The drive element 8 further has a tip 30 arranged at a radially outer edge of said drive element 8, and the tip 30 is adjacent to the inclined surface 29. Said tip 30 is formed in a continuous manner from the inclined surface 29 of the drive element 8. The tip 30 is the negative of the lower portion 18 of the

support

17, 18, so as to receive said lower portion 18 and hold the butt 19 of the sub-needle 6 in the respective active position, against the elastic force exerted by said arm 17, and/or to push axially the sub-needle 6.

The drive element 8 has a lower end 31, which lower end 31 can be brought into abutment with the contact surface 26 of the pusher head 7 in a one-sided axial resting manner.

A corresponding butt 32 formed in the radial direction is located in an axially intermediate region of the drive element 8. The drive element 8 rests radially on the elongated upper portion 23 and is free to slide axially with respect to said elongated upper portion 23. The butt 32 of the drive element 8 is fixed in the radial direction and moves in the axial direction.

The selector group 9 includes: an axial oscillating element 33 slidingly arranged in a corresponding longitudinal needle groove and below the pusher head 7, and an axial fixing element 34 able to be engaged by the needle selection device 200 (for example a needle selection device with a piezoceramic plate). The axial fixing element 34 is located in a radially outer position with respect to the axial fixing element 33 and has a plurality of radial teeth 35 arranged side by side like a comb.

The upper end of the axial oscillation element 33 of the selector group 9 has a corresponding contact surface 36, said contact surface 36 being directed or facing towards the lower contact surface 27 of the pusher head 7. These contact surface tables 27, 36 can be joined to each other in a one-sided axial resting manner.

The lower part of the axial oscillation element 33 of the selector group 9 has a respective butt 37 and a respective auxiliary butt 38 extending radially outwards. The auxiliary butt 38 is located at an upper axial position with respect to the butt 37.

The radially inner edge of the axial oscillating element 33 and/or the bottom surface of the needle groove, which partially abuts against said radially inner edge, are shaped so as to allow oscillation of said axial oscillating element 33.

The axial fixing element 34 can also oscillate by the influence of the needle selection device 200. The needle selection device 200 shown in fig. 5a, 5b and 7 has a plurality of elements (for example a plurality of piezoelectric ceramic plates) which selectively engage the radial teeth 35 of the axial fixed element 34 and cause the rotation of said axial fixed element 34, subsequently acting against the axial oscillating element 33.

The radially inner edge of the axial fixing element 34 and/or the radially outer edge of the axial swinging element 33 are shaped to allow relative swinging of the two elements.

In particular, the thrust of the axial fixed element 34 on the axial oscillating element 33 causes said axial oscillating element 33 to oscillate between an active position, in which the butt 37 and the auxiliary butt 38 project from the needle slot 4, and an inactive position, in which the butt 37 and the auxiliary butt 38 are retracted into said needle slot 4.

As shown in fig. 2c, in a different embodiment of the selector group 9, no axial fixing element is present. The axial oscillation element 33 of the selector group 9 comprises an elastically flexible extension 33a which extends downwards in a radially inner position with respect to the butt 37 and to the auxiliary break 38 and which is in contact with the bottom surface of the needle groove 4. The fixed comparison triangle 33b is in a radially outer position with respect to the axial oscillating element 33 and abuts against an axially intermediate ridge of the axial oscillating element 33. The fixed magnetic driver 33c is located at the upper end of the axial swinging member 33. The action of the magnetic actuator 33c causes the oscillation of the axial oscillating element 33 together with the elastic force exerted by the elastic flexible extension 33a and with the action of the comparison cam 33 b. The magnetic drive 33c can be selectively driven in order to cause, when appropriate, an oscillation of an axial oscillation element 33 contained in the coupling as part of a drive train connected to the given needle.

It is to be noted that the butt 37 and the auxiliary butt 38 of the selector group 9 are movable in the axial direction and in the radial direction; the auxiliary butt 22 of the auxiliary needle 6, the butt 25 of the pusher head 7 and the butt 32 of the driving element 8 move in the axial direction and are fixed in the radial direction; the butt 19 of the sub-needle 6 is movable in the axial and radial directions.

The radially fixed

butts

22, 25, 32 are always located outside the longitudinal needle groove 4. The

radially moving butt

19, 37, 38 is retracted in the longitudinal needle groove in the respective inactive position, which is outside the longitudinal needle groove 4.

The drive cam "C" is configured to receive and engage the radially fixed

butts

22, 25, 32 and the

radially moving butts

19, 37, 38.

As shown in fig. 1, the actuation cam "C" comprises a sub-needle cam 39, which is axially located on the sub-needle 6 and is configured for receiving and engaging the radially mobile butt 19 of said sub-needle 6. The sub-needle cam 39 defines a sub-needle track with which the radially movable butt 19 of the sub-needle 6 can engage. The radially moving butt 19 of the sub-needle 6, in the active position, protrudes out of the needle groove 4, so as to engage with these sub-needle tracks and cause the needle 3 to drive and the stitch to be formed. The radially mobile butt 19 of the sub-needle 6 is retracted in the inactive position so as not to engage with said sub-needle track.

The actuation cam "C" comprises a selector group cam 40, which is located at the bottom of the needle-holding cylinder 2, and the selector group cam 40 is configured for receiving and engaging the butt 37 of the axial oscillation element 33 of the selector group 9. The selector cam 40 defines a selector track with which the butt 37 of the axial oscillation element 33 can engage. The butts 37 of the selector jack group 9 extend out of the needle groove 4 in the operating position to engage with these selector jack group runways. The butt 37 of the selector jack 9 is retracted so as not to engage with the selector jack track at the non-operating position.

The drive cam "C" comprises a pusher cam 41, which is axially located in the lower portion 24 of the pusher head 7 and is configured for receiving and engaging the butt 25 of said pusher head 7. The pusher head cam 41 defines a pusher head track with which the radially fixed butt 25 of the pusher head 7 can engage. It may be noted that the pusher head track defined by the pusher head triangle 41 comprises: a basic runway at constant axial height, i.e. on a circumference, and a runway with a rise and a fall with variable axial height. The pusher cam 41, with which the butt 25 of the pusher 7 engages, is thus configured to axially guide the pusher 7 upwards or downwards.

The drive cam "C" comprises a drive element cam 42, which is located axially directly above the pusher head cam 41 and on the drive element 8, and is configured for receiving and engaging the butt 32 of said drive element 8. The drive element cam 42 defines a drive element track with which the radially fixed butt 32 of the drive element 8 can engage. It can be noted that the drive element track defined by the drive element cam 42 includes a basic track at a constant axial height, i.e., on a circumference, and a track with a variable axial height, both ascending and descending.

The drive cam "C" comprises a sub-needle cam 43, which is axially located directly above the sub-needle cam 39 and on the sub-needle 6, and is configured for receiving and engaging the sub-needle butt 22 of the sub-needle 6. The sub-needle cam 43 defines a sub-needle track, and the sub-radial fixed butt 22 of the sub-needle 6 can be engaged with the sub-needle track. It can be noted that the sub-course defined by the sub-cam 43 comprises a basic course at a constant axial height, i.e. on a circumference, and a course with ascending and descending slopes with variable axial height. Since the sub-needle cams 43 can be guided to the inactive position inside the cam body and therefore they cannot engage with the butt 22 of the sub-needle 6 which is radially fixed, at least some of the sub-needle cams 43 can be moved radially.

As shown in fig. 4a-4d, the sub-dart cams are shown in phantom lines in their inoperative position inside the cam body and in solid lines when they are in operation, i.e., extended relative to the bottom surface of the cam body.

The drive cam "C" comprises an auxiliary selector group cam 44, which is located directly above the selector group cam 40 and is configured for receiving and engaging the auxiliary butt 38 of the axial oscillation element 33 of the selector group 9. The auxiliary selector jack cam 44 defines an auxiliary selector jack track with which the auxiliary butt 38 of the axial swinging element 33 can engage. The auxiliary butts 38 of the selector jack group 9 in the active position are selected so as to engage with these auxiliary selector jack group runways. The auxiliary butt 38 of the selector jack in the inactive position can be retracted so as not to engage with the auxiliary selector jack runway. It can be noted that the auxiliary selector set track defined by the auxiliary selector set cam 44 includes a basic track at a constant axial height, i.e. on a circumference, and a track with a rise and a fall with a variable axial height. The selector group cam 40 with which the butt 37 of the selector group 9 engages and/or the auxiliary selector group cam 44 with which the auxiliary butt 38 of the selector group 9 engages guide the selector group 9 axially upward or downward.

It may be noted from fig. 1 that each of the runways has a respective first, second, third, fourth, fifth and sixth axial extension h1, h2, h3, h4, h5, h 6. The "axial extension" of the runway means the distance between the points of the runway that are furthest from each other, measured parallel to the central axis "X-X". In other words, the axial extension is the maximum axial height which the

butt

19, 22, 25, 32, 38, 37 can pass when the

butt

19, 22, 25, 32, 38, 37 is guided in the respective track and/or guided by the

respective cams

39, 43, 41, 42, 44, 40.

The maximum travel of the sub-needle 6 and the needle 3 corresponds to the fifth axial extension h 5. The maximum stroke of the sub-needle 6 and of the needle 3 can be limited by the radially mobile butt 19 in the active position and corresponds in this case to the first axial extension h 1. The maximum travel of the drive element 8 corresponds to the fourth axial extension h 4. The maximum travel of the pusher head 7 corresponds to the third axial extension h 3. The maximum stroke of the axial rocking element 33 of the selector group 9 corresponds to the second and sixth axial extensions h2, h 6.

It can be noted from fig. 1 that the maximum stroke of the

sub-needles

6 and 3, when the radially mobile butt 19 is in the inactive position (fifth axial extension h5), is longer than the maximum stroke of the pusher head 7 (third axial extension h3), which is then longer than the maximum stroke of the axially oscillating elements 33 of the selector group 9 (second and sixth axial extensions h2, h 6). For example, the maximum stroke of the

sub-needles

6 and 3, when the radially moving butt 19 is in the inactive position, is about 1.2 times the stroke of the pusher head 7 and about three times the maximum stroke of the axial movement unit 33 of the selector group 9.

In the embodiment shown, the maximum stroke of the sub-needle 6 and of the needle 3, when the radially mobile butt 19 is in the active position (first axial extension h1), is shorter than the maximum stroke of the sub-needle 6 and of the needle 3 when the radially mobile butt 19 is in the inactive position (fifth axial extension h 5). For example, the fifth axial extension h5 is about twice the first axial extension h 1.

The maximum stroke of the driving element 8 (fourth axial extension h4) is shorter than the maximum stroke of the sub-needle 6 and of the needle 3 (fifth axial extension h5) when the radially moving butt 19 is in the inactive position, and longer than the maximum stroke of the axial oscillating element 33 of the selector group 9. For example, the fourth axial extension h4 is about twice the second and sixth axial extensions h2, h6 and is about 2/3 of the fifth axial extension h 5.

The drive chain 5 is therefore configured for separating the axial movement of the needle 3 and/or of the sub-needle 6 from the axial movement of the pusher head 7 and/or of the selector group 9; the axial movement of the driving element 8 can be indeed decoupled from the pusher head 7 and/or the needle 3 and/or the sub-needle 6 and/or the first of the selector group 9.

Moreover, the drive chain 5 is configured to decouple the axial movement of the pusher head 7 and/or of the selector group 9 from the driving/stopping (switching between the inactive position or inactive needle and active position) of the radially moving butt 19 of the sub-needle 6.

The drive train described and constituting the object of the present invention can be arranged in cooperation with the drive cam "C" and the needle selecting device 200 according to a plurality of configurations shown in, for example, fig. 3a to 3i and fig. 3l to 3 t.

In fig. 3a, the butt 37 is retracted in the corresponding longitudinal needle groove 4 or disengaged from the corresponding selector group cam 40. The axial oscillating element 33 of the selector group 9 is in the axially lowest position, the pusher 7 rests on the axial oscillating element 33 and its butt 25 follows the basic course of the pusher cam 41 with constant axial height. The butt 32 of the drive element 8 follows the basic course of the drive element cam 42 with constant axial height. The auxiliary butt 22 of the sub-needle 6 follows the basic course of the auxiliary sub-needle cam 43 with constant axial height. The driving element 8 is axially spaced from the sub-needle 6, the butt 19 of the sub-needle 6 being in the inactive position, disengaged from the corresponding sub-needle cam 39. The distal end 28 of the pusher head 7 is spaced from the lower contact surface 16 of the projection 14. The height of the needle 3 is determined by the axial position of the auxiliary butt 22.

In fig. 3b, the selection device 200 acts on the axial fixed element 34 and causes the rotation thereof and therefore the rotation of the axial oscillating element 33, so that the butt 37 and the auxiliary butt 38 are taken out of the longitudinal needle groove 4 and engage with the selector group cam 40 and the auxiliary selector group cam 44. The other elements are in the position of fig. 3 a.

In fig. 3c, the butt 37 of the axial oscillating element 33 is pushed axially upwards by the selected stitch group cam 40 and pushes against the pusher head 7, which pusher head 7 then pushes against the sub-needle 6. As a result, the butt 25 of the pusher head 7, and possibly the auxiliary butt 22 of the auxiliary needle 6, enter and reach the respective runways with variable axial height, the pusher head 7 and the auxiliary needle 6 starting to rise together with the needle 3. The drive element 8 is axially separated from the other components, so that the drive element 8 is radially fixed.

In fig. 3d, the pusher head 7, the sub-needle 6 and the needle 3 are moved upward by the pushing force exerted by the pusher cam 41 and/or the selector group cam 40. The pusher head 7 pushes directly against the sub-needle 6 so as to guide it upwards. The drive element 8 is axially fixed.

In fig. 3e, pusher head 7, sub-needle 6 together with needle 3 are supported by pusher head cam 41, while axial oscillating element 33 is guided downwards by selected blade group cam 40 and is separated from pusher head 7.

In fig. 3f, the pusher head triangle 41 pushes the pusher head 7 upwards, said pusher head 7, in addition to lifting the sub-needle 6 and the needle 3, coming into contact with the drive element 8 and pushing the drive element 8 upwards. As a result, when the butt 32 of the drive element 8 finds the track of the drive element cam 42 with variable axial height, the butt 32 of the drive element 8 engages and can be lifted by the track, and subsequently the pusher head 7 can be detached from the drive element 8. At the same time, the axial oscillating element 33 is axially spaced from the pusher head 7.

In fig. 3g, the sub-needle 6 is axially fixed together with the needle 3 and the pusher head 7, while the driving element triangle 42 lifts the driving element 8, the driving element 8 being close to the sub-needle 6 but not engaged with the sub-needle 6.

In fig. 3h, the pusher cam 41 guides the pusher 7, the sub-needle 6 and the needle 3 upwards, moving the sub-needle 6 away from the drive element 8.

In fig. 3i, the pusher head 7, the sub-needle 6 and the needle 3 are fixed in the axial direction, and the driving element 8 is moved upward by the (driving element cam) driving element cam 42.

In fig. 3l, the pusher head cam 41 and the sub-hand cam 43 guide the pusher head 7, the sub-hand 6 and the needle 3 axially downward. The drive element cam 41 also guides the drive element 8 downwards.

In fig. 3m, the sub-needle cam 43 guides the pusher head 7, the sub-needle 6 and the needle 3 axially downwards, while the driving element cam 42 pushes the driving element 8 upwards until the inclined surface 29 is axially inserted under the sub-needle tail 20, radially interposing the inclined surface 29 between the pusher head 7 and said sub-needle tail 20, against the elastic force exerted by the

supports

17, 18.

In fig. 3n, the pusher cam 41 and the sub-needle cam 43 guide the pusher 7, the sub-needle 6 and the needle 3 downwards, while the driving element ends its stroke and is axially fixed, with the sub-needle tail 20 in the tip 30 and the butt 19 of the sub-needle 6 in the respective active position.

In fig. 3o, the butt 19 and the sub-butt 22 of the sub-needle 6 engage with the respective sub-needle cam 39 and sub-needle cam 43 and also move integrally downwards in the axial direction together with the drive element 8. The pusher head 7 is spaced from the sub-needle 6 and is moved downward by a pusher head triangle 41 times.

It can be noted in fig. 3 e-3 i and 3l-3o that the axial swinging element 33 is always spaced from the pusher head 7.

In fig. 3p, the butt 19 and the sub-butt 22 of the sub-needle 6 engage with the respective sub-needle cams 39 and sub-needle cams 43 and also move integrally downwards in the axial direction together with the drive element 8. The pusher head 7 abuts against the selector plate set 9.

In fig. 3q, the sub-needle 6 and the needle 3 are guided upward by the sub-needle cam 43, the driving element 8 is guided downward by the driving element cam 42 and separated from the sub-needle 6, and the butt 19 of the sub-needle 6 is switched back to the non-operating state by the elastic force of the elastic lever 17. Then, a substantially radial elastic force acts on the support 18 of the butt 19 of the sub-needle 6 in order to keep the butt 19 in the inactive position.

In fig. 3r, the pusher head cam 41 and the driving element cam 42 guide the pusher head 7 and the driving element 8, respectively, downwards, while the needles 3 and the sub-needles 6 remain fixed in the non-knitting position.

In fig. 3s, the needle and sub-needle 6 are pushed upwards, while the drive element 8 is in a fixed axial position, and the pusher head 7 is guided by the pusher head triangle 41 against the drive element 8.

Fig. 3t shows the transfer position of the needle 3, in which the needle 3 and the sub-needle 6 are pushed upwards by the sub-needle cam 43 and spaced from the pushing head 7 and the drive element 8.

As can be noted from fig. 3r and 3s, the axial swinging element 33 is axially spaced from the pusher head 7.

By setting the above-described structural combinations to a predetermined sequence, the needles 3 are moved due to the structure of the driving cam so as to perform a desired knitting operation.

By way of simple example, fig. 4a-4d illustrate some of the work sequences. The sense of rotation of the needle-holding cylinder 2 with respect to the triangle seat of the drive triangle "C" is shown by the arrow "CCW" (first rotation or counterclockwise rotation of the needle 3 and of the drive chain 5 with respect to the drive triangle "C"). The length of the track of the butt engaging with the respective cam has been indicated by a plurality of vertical bars, while the length of the track of the butt disengaging from the respective cam has been indicated by a horizontal dotted line. The runway of the end of the needle 3 is not shown, but it is always parallel to one butt 22 of the sub-needle 6 to which the needle 3 is integrally connected during the vertical movement.

Fig. 4a shows the step (step) for the tucker needle (served needle) 3. The

vertical lines

3b, 3d and 3g represent the three positions of the needle 3 and of the drive chain 5, the configuration of which corresponds to that of figures 3b, 3d and 3 g. This means that, viewing fig. 4a from the right side to the left side, the butt 37 of the selector group 9 is driven and engaged with the selector group cam 40, and is lifted upward due to the ascending slope 100, and pushes up the pusher head 7, the sub needle 6, and the needle 3, so that the butt 25 of the pusher head 7 is engaged with and follows the ascending slope 101 of the pusher head cam 41 (tucker raising cam). The sub-hand cam 43 is in the inactive position. The radially moving butt 19 of the sub-needle 6 is in the inactive position. The needle 3 is guided to the position of fig. 3g by the pusher cam 41, while the pusher 7 is separated from the selector group 9.

Fig. 4b shows the procedure for case-off needle 3. The

vertical lines

3b, 3c, 3e, 3i and 3h represent five positions of the needle 3 and of the drive chain 5, the configuration of which corresponds to that of fig. 3b, 3c, 3e, 3i and 3 h-this means that, viewing fig. 4b from the right to the left, the butt 25 of the pusher head 7 is first lifted by the selector jack group 9 (fig. 3b and 3c) and cooperates with the pusher head cam 41 (the knockover needle raising cam 102) to guide the needle 3 in the position of fig. 3 i.

Fig. 4c shows the step with the needle 3 at the transfer height. The vertical line 3t represents the five positions of the needle 3 and of the drive chain, the configuration of which corresponds to that of figure 3 t. This means that, viewing fig. 4c from the right to the left, an auxiliary sub-needle cam 43 is guided to the respective active position and the auxiliary butt 22 of the sub-needle 6 engages with the ramp 103 of said cam, until the needle 3 is guided to the position of fig. 3t, the pusher head 7, the drive element 8 and the selector group 9 being maintained in the lower axial position.

Fig. 4d shows the step of lowering the needle 3. The

vertical lines

3b, 3c, 3e, 3h, 3i, 3l, 3m, 3n, 3o, 3p, 3q represent eleven positions of the needle 3 and of the drive chain, the configuration of which corresponds to that of fig. 3b, 3c, 3e, 3h, 3i, 3l, 3m, 3n, 3o, 3p, 3 q. This means that some of the sub-trocar triangles 43 are guided to the respective working positions, viewing fig. 4d from the right side to the left side. The needle 3 and the sub-needle 6 are first guided downwards by the sub-butt 22, the sub-butt 22 operating in cooperation with the

descent

104, 105 defined by the sub-needle cam 43, the needle 3 and the sub-needle 6 then being guided to their active position (fig. 3m, 3n, 3o, 3p and the

vertical lines

3m, 3n, 3o, 3p) by the radially moving butt 19 and engaging the descent 106.

Described above are embodiments of a method for moving the needles of a circular knitting machine, object of the present invention, which more generally comprise the radial movement of the butt 19 of the sub-needle 6 between an active position, in which the butt 19 is selected so as to engage with the corresponding sub-needle track defined by the sub-needle cam 39 and cause the actuation and stitch formation of the needle 3, and an inactive position (non-active needle); in the inactive position (inactive needle), the butt 19 is retracted so as not to engage with the sub-track. The radial movement of the butt 19 of the sub-needle 6 is caused by the relative axial movement between the sub-needle 6 and the driving element 8 axially below the sub-needle 6, and is decoupled/independent from the axial movement of the pusher head 7 and of the selector group 9, at least in some steps.

Additional features relating to the shape of the drive triangle "C" will be pointed out below in connection with fig. 5a and 5 b. The triangular portion of fig. 5a and 5b shows the situation on the plane of half of the driving triangle "C". The other half is the same as shown in fig. 5a and 5 b. Two yarn feeders 110 arranged one after the other in the circumferential direction are schematically shown in fig. 5a and 5 b. This section thus corresponds to two of the four yarn feeders 110 of the machine 1.

Each yarn feeder 110 is associated with a triangle which is symmetrical with respect to said yarn feeder 110, i.e. with respect to an axis of symmetry "Y" parallel to the central axis "X-X" and passing through the yarn feeder 110. Furthermore, the triangle is also symmetrical about a middle axial line "Z" located between the two yarn feeders 110. This symmetry allows the machine 1 to operate both in rotation in both directions and in the swing mode. .

The parts of the sub needle cam 39, the sub needle cam 43, the driving element cam 42, the pusher head cam 41, the selector jack cam 40, and the sub selector jack cam 44 between the two successive symmetry axes "Y" represent a first module that repeats (four times in the illustrated embodiment) over the entire circumference of the cam base of the driving cam "C".

The parts of the sub needle cam 39, the sub needle cam 43, the driving element cam 42, the pusher head cam 41, the selector jack cam 40, the sub selector jack cam 44, between two successive intermediate axial straight lines "Z", represent a second module which is repeated (four times in the illustrated embodiment) over the entire circumference of the cam housing of the driving cam "C".

The triangular portion between two successive symmetry axes "Y" is symmetrical with respect to an intermediate axial straight line "Z" located between the two symmetry axes "Y". The triangular portion between the two intermediate axial straight lines "Z" is symmetrical about the symmetry axis "Y" located between the two intermediate axial straight lines "Z". Fig. 5a and 5b show two second modules side by side, or one first central module and two half first modules beside.

Referring to the single second module, the sub-prosthetic needle triangle 43 (symmetrical about the symmetry axis "Y") includes a central triangle 111 and two side triangles 112 located at opposite sides of the central triangle 111. The central cam 111 and each lateral cam 112 define a

respective descent

113, 114 and their function is to lower the butt 22 of the sub-needle 6. Fig. 4d shows the descent of one of the inclined sides of the center cam 111 and only one side cam 112 when the butt 22 of the sub needle 6 moves with respect to the sub needle cam 43 in the middle direction of the case. When the movement of the butt 22 of the sub needle 6 in the opposite direction with respect to the sub needle cam 43 occurs, the inclined sides of the center cam 111 and the other side cam 112 act.

The cam 39 comprises two downslopes 106 (the function of which is shown in fig. 4 d), the downslopes 106 being arranged symmetrically about the axis of symmetry "Y". Here again, the two downslopes 106 act alternately depending on the direction of rotation.

The drive element race defined by the drive element triangle 42 includes the base race having a constant axial height and two pairs of symmetrical (about axis of symmetry "Y") upslopes. Each pair comprising: an upper ramp 115 and a lower ramp 116 for the drive element 8. The two pairs of upslopes merge into a middle region 117, the middle region 117 being defined by a respective substantially horizontal length.

The pusher head runway defined by the pusher head triangle 41 has a first pair and a second pair of upslopes, which are symmetrical about the axis of symmetry "Y" and move up and down, merging towards said axis of symmetry "Y".

Each pair of upslopes includes the above-described knockover needle raising cam 102 and tucker needle raising cam 101. The first and second pairs of tuck-and-drop needle-raising cams are associated with respective yarn feeders 110 and are symmetrical with respect to said yarn feeders 110.

The two pairs act alternately as upslopes depending on the direction of rotation. Because of their symmetry, only one of the two pairs is described below, which is active when the drive chain 5 rotates about the central axis "X-X" in a counterclockwise direction of rotation "CCW" relative to the drive triangle "C".

The knockover setting cam 102 and the tucker setting cam 101 are separated from the basic racetrack at a constant axial height, extend parallel to each other, and merge in an intermediate zone 119 aligned with the respective yarn feeder 110.

In more detail, the knockover lift cam 102 is a part of a descending stitch pushing head track formed from a basic track, raised by said knockover lift cam 102, having a substantially horizontal length 120, which is immediately followed (i.e. located immediately downstream) by the knockover lift cam 102 and the successive knockover lift cam 121.

The tucker raising cam 101 is a part of a tucker pusher head track formed from the basic track, is raised by the tucker raising cam 101, and merges with a knockover needle lowering cam 121 in the middle area 119. The tucker and drop

stitch cams

101, 102 merge with each other after (i.e. downstream) the respective maximum height point, so that the yarn feeder 110 follows (i.e. is located downstream) the respective maximum height points of the tucker and drop

stitch cams

101, 102.

With reference to the drive chain "5" rotating in a counterclockwise direction of rotation "CCW" (from right to left in fig. 5a) with respect to the drive cam "C", the entry of the knockover needle raising cam 102 circumferentially precedes the entry of the tucker needle raising cam 101, and there is no further entry or runway between the two said entries for pushing the butt 25 of the head 7. Moreover, the exit of the knockover setting cam 102 is directly preceded by the exit of the tucker setting cam 101 and there is no further runway for the butt 25 of the head 7 between the two said exits.

The maximum height, axial extension, circumferential extension and overall length of the knockover setting cam 102 are greater than the corresponding dimensions of the tucker setting cam 101.

The drop stitch push head track is above the tuck stitch push head track and the two tracks merge into each other to form a middle area 119.

The auxiliary selector jack cam 44 of the single module comprises a cam 122 symmetrical about the corresponding axis of symmetry "Y". The cam 122 is provided with two downslopes which operate alternately according to the direction of rotation of the machine 1, as shown in fig. 4b or 4 d. The auxiliary selector jack cam 44 also includes a circular sector 123 (straight in the planar development of fig. 5a).

The selector set runway 40 comprises a single track 124, which single track 124 has, in the second module considered, a non-control zone 125 associated with the yarn feeder 110, symmetrical with respect to said yarn feeder 110 and symmetrical with respect to the symmetry axis "Y". The single track 124 further comprises two needle guard triangle sections (with peaks and valleys), each arranged at one of the two sides of the non-controlled zone 125, and which are also symmetrical with respect to the yarn feeder 110.

Considering the first module between the two axes of symmetry "Y", the two needle-guard triangular segments partially form a needle-guard triangular segment 126 located between two successive non-control zones 125. The needle guard triangular section 126 is symmetrical about the middle axial line "Z".

The needle guard triangular section 126 includes: a needle-raising middle high point 127 symmetrical about the middle axial straight line "Z", and both side high points 128 disposed at the sides of the needle-raising middle high point 127. A respective valley (or valley) is defined intermediate the lift pin intermediate high point 127 and each side lobe 128.

The lift pin intermediate high point 127 and the side projections 128 have inclined sides or inclined sections that perform various functions and are symmetrical according to the rotation of the pin 3 and the drive chain 5 with respect to the drive triangle "C".

With reference to the drive chain 5 rotating about the center axis "X-X" in the counterclockwise rotational direction "CCW" (from right to left in fig. 5a) with respect to the drive cam "C", the first side (the right side in fig. 5a) of both sides of the needle raising middle high point 127 is set with the first needle raising cam 129, and the first side (the right side in fig. 5a) of both sides of the subsequent side cam 128 is set with the second needle raising cam 100. The first needle raising cam 129 precedes the second needle raising cam 100 in the circumferential direction, and the two ascending

slopes

129, 100 are connected by a first needle lowering cam 131 defined by a second side (the left side in fig. 5a) of both sides of the needle raising middle high point 127. A second descending cam 132 defined by a second side (the left side in fig. 5a) of both sides of the side projection 128 is connected to the non-control area 125. The first set-up cam 129, the first drop cam 131, the second set-up cam 100 and the second drop cam 132 are depicted as operating for following (i.e. located downstream) their first yarn feeder 110.

The needle protection cam section has a substantially constant axial width, so that the axial extension of the first needle raising cam 129 is substantially the same as the axial extension of the second needle raising cam 100. Moreover, the circumferential extension of the first needle raising cam 129 is substantially the same as the circumferential extension of the second needle raising cam 100, and the first and second

needle raising cams

129, 100 run substantially parallel to each other.

The first set-up cam 129 is operatively associated with the knockover set-up cam 102 and the second set-up cam 100 is operatively associated with the tucker set-up cam 101.

In particular, the first stitch cam 129 is offset in the circumferential direction with respect to the knockover stitch cam 102 in advance, so that the maximum height of the first stitch cam 129 precedes in the circumferential direction the entry of the corresponding knockover stitch cam 102. It can be noted that the intermediate axial straight line "Z" passing through the maximum height of the first lift cam 129 is located just before the corresponding knockover lift cam 102.

The second raising cam 100 is offset in the circumferential direction in advance with respect to the corresponding tucker raising cam 101 so that the bottom of the second raising cam 100 precedes the entrance of the corresponding tucker raising cam 101 in the circumferential direction and the maximum height of the second raising cam 100 precedes the maximum height of the corresponding tucker raising cam 101 in the circumferential direction.

When the machine 1 is operated in the opposite direction of rotation, i.e. in the second or clockwise direction "CW" (shown in fig. 5b), the second of the two sides of the needle-raising middle high point 127 (the left side in fig. 5b) defines a first needle-raising cam 129 and the first of the two sides (the right side in fig. 5b) defines a first needle-lowering cam 131. The other of the side lobes 128 defines a second needle raising cam 100 (second side) and a second needle lowering cam 132 (first side). The first and second set-up and drop cams operate for the second yarn feeder 110 and cooperate with a pair of cast-off set-up cam 102 and set-up cam 101 located immediately behind (downstream) thereof.

In general, the needle protection triangle 126 located between two consecutive yarn feeders 110 operates for the one of the two yarn feeders 110 following (downstream) the needle protection triangle 126, depending on the direction of rotation. By reversing the direction, the same needle guard triangle 126 operates for the other yarn feeder 110.

The non-control area 125 has two exit ramps 133 at opposite ends thereof. Each exit ramp 133 extends between the bottom surface and the radially more outer surface of the single track 124 to serve as a connector. The ramp 133 is (better) shown in fig. 6.

Fig. 5a and 5b further schematically show the selection device 200 between two successive feeders 110 or on the respective needle-care triangle 126. The needle selection device 200 comprises two drivers 201,202 arranged circumferentially side by side and located in respective valleys (or valleys) defined by the needle shield triangle sections 126, between the needle raising middle high point 127 and each side protuberance 128.

Each actuator 201,202 is of piezoelectric type with selector blade tips.

In the embodiment shown in fig. 7 and 8, the drivers 201,202 comprise: a first set of needle selection knives 203 and a second set of needle selection knives 204 projecting from the front surface of the actuators 201,202 are directed towards the radial teeth of the needle-holding cylinder 2 and of the selector group 9 when the actuators 201,202 are mounted on the knitting machine 1 in the active position. Each selector blade 203,204 comprises a plurality of selector blade heads 205,206, which overlap and are aligned along a respective common vertical axis "K-K", and the second set of selector blades 204 axially overlaps the first set of selector blades 203. Preferably, the two needle selection knives 203,204 are arranged along the same common vertical axis "K-K" and one above the other.

As better shown in fig. 8, each selector blade head 205,206 has a symmetrical shape with respect to a plane of symmetry "W-W" in which the common vertical axis "K-K" lies. The selector blade heads 205 of the first array 203 are symmetrical with respect to the stems 206 of the second array 204.

Each selector blade head 205,206 oscillates between a first raised position and a second lowered position about a respective horizontal axis orthogonal to the common axis, by means of piezoelectric control managed by the control unit of the machine 1. By said oscillation, the selector blade heads 205,206 are raised and/or lowered (arrow "F" in fig. 7) and interact with the corresponding teeth 35 of the selector group 9 to cause the oscillation of the axial fixing element 34 and, as a result, the oscillation of the axial oscillation element 33.

As shown in fig. 7 and 8, the selector blade heads 205,206 of the first and second arrays 203,204 have respective first and second engagement surfaces 401, 402 which are in contact with the teeth 35 of the selector jack group 9.

In the illustrated embodiment, the first engagement surface 401 lies in a first common plane that is inclined relative to the plane of symmetry "W-W", the second engagement surface 402 lies in a second common plane that is inclined relative to the plane of symmetry "W-W", and the first, second and symmetry planes "W-W" intersect an intersection line that is parallel to the common vertical axis "K-K". As a result, the first engagement surface 401 and the second engagement surface 402 are inclined toward opposite sides of the symmetry plane "W-W".

In other embodiments not shown, the first engagement face 401 is located in a plurality of first inclined faces and the second engagement face 402 is located in a plurality of second inclined faces. The first and second planes are inclined toward opposite sides of a symmetry plane "W-W" and define different angles with respect to the pair of vehicle planes "W-W".

In the shown embodiment, the selector blade heads 205 of the first set of selector blades 203 are all movable together about a respective horizontal axis, and the selector blade heads 206 of the second set of selector blades 204 are all movable together about a respective horizontal axis, and the two arrays are independently movable.

As explained below, the first group of needle selectors 203 is configured to operate, i.e. to engage with the teeth 35 of the selector group 9 of the machine 1, if the rotation of the needle-holding cylinder 2 with respect to the drive triangle "C" occurs in the counterclockwise direction "CCW", and the second group of needle selectors 204 is configured to operate, i.e. to engage with the teeth 35 of the selector group 9 of the machine 1, if the rotation of the needle-holding cylinder 2 with respect to the drive triangle "C" occurs in the clockwise direction "CW".

According to the method of moving the needle 3 according to the invention, in order to form a drop stitch by the movement of the needle 3 and the drive chain 5 shown in fig. 4b, the axial fixing element 34 of the selector group 9 with the radial toothing 35 is moved "CCW" in a counter-clockwise direction of rotation before the first and

second drivers

201, 202.

The first group of needle selector blades 203 of the first driver 201 acts on the axially fixed element 34 to cause the oscillation of the axially oscillating element 33 and the snapping of the butt 37 into a first starting point 300 of the single track 124, said first starting point 300 being located at the bottom valley (or valley) of the needle-protection triangle segment of the first needle cam 129 (fig. 4b and 5a). The relative rotation between the actuation cam "C" and the needle-holding needle cylinder 2 causes the butt 37 to slide into the single track 124 and onto the first lift cam 129. The axial oscillating element 33 of the selector group 9 is lifted upwards and pushes the pusher head 7 upwards until the butt 25 of the pusher head 7 engages in the knockover setting cam 102 (fig. 4b and 5a).

As the corresponding butt 25 slides onto the knockover needle raising cam 102, to the point of maximum height situated on the substantially horizontal length 120, the pusher head 7 is further raised and disengages from the axial oscillation element 33 of the selector group 9 and lifts the needle 3 so as to form the drop stitch. The butt 25 of the pusher head 7 then passes over the knockover needle lowering cam 121 and the intermediate zone 119 and descends again, passing over the uphill 101 of another pair (fig. 4b) (working as a downhill in this step).

When the pusher head 7 is lifted and slides onto the knockover lifting cam 102 and then descends again, the butt 37 of the axial oscillation element 33 of the selector group 9 moves along the single trajectory 124, successively goes over the first drop cam 131, the second lifting cam 100, the second drop cam 132 and enters the non-control zone 125 (fig. 4 b). On continuing the advancement, the butt 37 of the axial oscillation element 33 of the selector group 9 encounters the exit ramp 133, said exit ramp 133 pushing said butt 37 radially inwards and separating it from the single trajectory 124 (fig. 4 b). The butt 37 of the selector group 8 leaves the single trajectory 124 and then enters the corresponding needle slot of the needle-holding needle cylinder 2.

In order to form tucks by the movement of the needle 3 and of the drive chain 5 shown in fig. 4a, the first set of needle selectors 203 of the second drive 202 acts on the axially fixed element 34 for causing the oscillation of the axially oscillating element 33 and the snapping of the butt 37 into the second take-up point 301 of the single track 124, said second take-up point 301 being located in the valley (valley) of the needle triangle segment at the bottom of the second take-up cam (100) (fig. 4a and 5a).

The relative rotation of the drive cam "C" and of the needle-holding needle cylinder 2 causes the butt 37 to slide onto the second needle-raising cam 100, the axial oscillating element 33 of the selector group 9 is lifted upwards and pushes the pusher head 7 upwards until the butt 25 of the pusher head 7 snaps into the tucker needle-raising cam 101 (fig. 4a and 5a).

As the corresponding butt 25 slides onto the tucker raising cam 101, to the point of maximum height located on the intermediate zone 119, the pusher head 7 is raised further and lifts the needle 3 in order to form tucks. The butt 25 of the pusher head 7 then passes over the intermediate zone 119 and descends again, passing over the uphill 101 of another pair (figure 4a) (operating as a downhill in this step)

When the pusher head 7 is lifted and slides onto the tucker raising cam 101 and descends again with hand, the butts 37 of the axial oscillation elements 33 of the selector group 9 move along a single trajectory 124, sequentially passing over the second lowering cam 132 and entering the non-control zone 125 (fig. 4a), so as to then engage the outlet ramps 133, which outlet ramps 133 push said butts 37 radially inwards and make them disengage from the single trajectory 124 (fig. 4 a). The butt 37 of the selector group 9 leaves the single trajectory 124 and enters with hand into the corresponding needle slot of the needle-holding cylinder 2.

If the direction of rotation is clockwise "CW" as shown in fig. 5b, the second driver 202 acts on the axially fixed element 34 with the second set of needle selector blades 204 for causing the oscillation of the axially oscillating element 33 and the engagement of the butt 37 into the first needle raising point 300 located at the bottom of the first needle raising cam 129 (to form a lowering stitch), and the second set of needle selector blades 204 of the first driver 201 acts on the axially fixed element 34 for causing the oscillation of the axially oscillating element 33 and the engagement of the butt 37 into the second needle raising point 301 located at the bottom of the second needle raising cam 100 (fig. 5b) (to form a tuck).

It is noted that when the rotation direction is reversed, the two sides of the needle raising middle high point 127 are functionally reversed (first side-first needle raising cam 129, second side-first needle lowering cam 131; first side-first needle lowering cam 131, second side-first needle raising cam 129).

In general, if the needle-holding cylinder 2 rotates in the counterclockwise direction "CCW" with respect to the driving cam "C" (fig. 5a), the butt 37 of the selector group 9 slides to the first side of the needle raising middle high point 127 for raising the pusher head 7 until the butt 25 of the pusher head 7 engages with the knockover needle raising cam 102 associated with the first yarn feeder 110. Alternatively, the butt 37 of the selector group 9 slides onto the first side of the side projection 128 to lift the pusher head 7 until the butt 25 of the pusher head 7 engages the tucker raising cam 101 associated with the first feeder 110. Further, the first group selector blade 203 of the first actuator 201 acts on the selector group 9 for engaging the butt 37 into the first starting point 300 and forming a drop stitch on the first yarn feeder 110, and the first group selector blade 203 of the second actuator 202 acts on the selector group 9 for engaging the butt 37 which has not been engaged with the first actuator 201 in advance into the second starting point 301 and forming a tuck on the yarn feeder 110.

If the needle-holding cylinder 2 is rotated in the clockwise direction "CW" with respect to the driving cam "C" (fig. 5b), the butt 37 of the selector group 9 slides to the second side of the needle-raising middle high point 127 for raising the pusher head 7 until the butt 25 of the pusher head 7 engages the lower knockover needle-raising cam 102 associated with the second thread feeder 110. Alternatively, the butt 37 of the selector group 9 slides onto the second side of the side projection 128 to lift the pusher head 7 until the butt 25 of the pusher head 7 engages the tucker raising cam 101 associated with the second feeder 110. Moreover, the second group of needle selection knives 204 of the first actuator 201 act on the selector group 9 for engaging the butt 37 in the first pick up point 301 and forming tucks on the different adjacent first yarn feeders 110, and the second group of needle selection knives 204 of the second actuator 202 act on the selector group 9 for engaging the butt 37 in the second pick up point 301 and forming drop stitches on said different adjacent yarn feeders 110.

The invention achieves important advantages.

First, the present invention overcomes the deficiencies of the prior art.

In particular, the invention allows to produce circular machines operating only in rotation or with reciprocal rotation:

compact in both axial and radial directions;

it is possible to manufacture tubular fabrics with small radial dimensions, even less than 165 mm;

have less severe restrictions on the needle movement for making more complex fabrics;

more compact than known machines, allowing to obtain needle movements more complex than those of large machines of the same needle count;

a higher (even doubled) number of "lanes", i.e. feed points, with respect to the prior art and the same cylinder diameter;

-capable of performing an "intarsia art" design, i.e. a coloured pattern without floating lines on the back;

the ability to produce three-dimensional textile products without changing the fabric density and without adding yarn cutting processes.

Claims

1. A selector head for circular knitting machines comprising:

a first set of needle selection blades (203) and a second set of needle selection blades (204), each of the first set of needle selection blades (203) and the second set of needle selection blades (204) comprising a plurality of needle selection blade heads (205,206) arranged in succession along a common axis (K-K);

wherein the second set of needle selection blades (204) and the first set of needle selection blades (203) are arranged one after the other along the common axis (K-K);

wherein the first set of needle selectors (203) is configured to engage with the teeth (35) of the selector group (9) of the circular knitting machine (1) if the relative rotation of the needle-holding cylinder (2) of the circular knitting machine (1) with respect to the actuation cam (C) occurs in a first direction of rotation (CCW);

wherein the second group of needle selectors (204) is configured to engage with the teeth (35) of the selector group (9) if the relative rotation of the needle-holding cylinder (2) of the circular knitting machine (1) with respect to the actuation cam (C) occurs in a second direction of rotation (CW) opposite to the first direction of rotation (CCW).

2. The selector head according to claim 1, wherein each selector blade head (205,206) is movable between a first position and a second position in dependence of a control, wherein the selector blade heads (205) of the first set of selector blades (203) are movable independently of the selector blade heads (206) of the second set of selector blades (204).

3. The selector head according to claim 2, wherein the selector blade heads (205) of the first set of selector blades (203) are all movable together and the selector blade heads (206) of the second set of selector blades (204) are all movable together.

4. Selector head according to claim 2, wherein the selector blade heads (205) of the first group of selector blades (203) are movable around respective axes orthogonal to the common axis (K-K) and the selector blade heads (206) of the second group of selector blades (204) are movable around respective axes orthogonal to the common axis (K-K).

5. Selector head according to any one of claims 1 to 4, wherein the selector blade heads (205) of the first group of selector blades (203) have respective first engagement surfaces (401) for the teeth (35) of the selector set (9), and wherein the selector blade heads (206) of the second group of selector blades (204) have respective second engagement surfaces (402) for the teeth (35) of the selector set (9); wherein the first engagement surface (401) and the second engagement surface (402) are inclined in opposite directions.

6. The selector head as claimed in claim 5, wherein the selector blade heads (205) of the first set of selector blades (203) are symmetrical to the selector blade heads (206) of the second set of selector blades (204) with reference to a plane of symmetry (W-W) in which the common axis (K-K) lies.

7. The selector head according to claim 6, wherein the first engagement surface (401) lies in a first common inclined plane or a plurality of first inclined planes with respect to the plane of symmetry (W-W), and wherein the second engagement surface (402) lies in a second common inclined plane or a plurality of second inclined planes with respect to the plane of symmetry (W-W).

8. The selector head according to claim 6, wherein the first engagement surface (401) and the second engagement surface (402) are inclined towards opposite sides of the plane of symmetry (W-W).

9. A circular knitting machine comprising:

-a needle-holding needle cylinder (2) having a plurality of longitudinal needle slots (4) arranged around a central axis (X-X) of the needle-holding needle cylinder (2);

-a plurality of needles (3), each of which is housed in a respective longitudinal needle groove (4);

-at least one yarn feeder (110) operatively associated with the needle (3);

-an actuation cam (C) arranged around the needle-holding needle cylinder (2) and movable with respect to said needle-holding needle cylinder (2) about a central axis (X-X) for inducing or allowing a movement of the needles (3) along the longitudinal needle slots (4) so as to enable stitch formation by said needles (3);

-a drive chain (5) for each needle (3), which is inserted in a respective longitudinal needle slot (4), is located below the respective needle (3), and which is operatively placed between the respective needle (3) and the drive cam (C);

wherein the drive chain (5) comprises:

a selector group (9), arranged below the needles (3), having at least one respective butt (37) radially movable between an operating position, in which it is extracted to engage with a respective selector group path defined by a selector group cam (40), and a non-operating position; when in the non-operation position, the needle butt retracts so as not to be clamped with the needle selector set path;

at least one selector device (200) acting on said group of selectors (9) for switching or holding the group of selectors (9) in the operating or non-operating position;

wherein the needle selection apparatus (200) comprises:

at least one selector head (201,202) according to any one of the preceding claims.

10. The circular knitting machine according to claim 9, wherein the needle selection device (200) comprises two selector heads (201,202) placed circumferentially side by side, wherein the first set of needle selection knives (203) of each of the two selector heads (201,202) engages the teeth (35) of the selector group (9) if a relative rotation of the needle-holding needle cylinder (2) with respect to the drive cam (C) is produced in the first direction of rotation (CCW); wherein the second set of selector knives (204) of each of the two selector heads (201,202) engage the teeth (35) of the selector set (9) if a relative rotation of the needle-holding cylinder (2) with respect to the drive cam (C) occurs in a second direction of rotation (CW) opposite to the first direction of rotation (CCW).

11. Circular knitting machine according to claim 9 or 10, comprising at least two feeds (110) and at least two selector groups (9), each selector group being located between two subsequent feeds (110).

12. A circular knitting machine according to claim 9 or 10, wherein the knitting machine is of the variable rotary action type.

13. A method for moving a circular knitting machine, wherein the circular knitting machine is manufactured according to any of claims 9 to 12, the method comprising the steps of:

generating a relative rotation between the needle-holding needle cylinder (2) and the actuation cam (C);

acting on the selector group (9) by means of the needle selection device (200) so as to move or hold the respective butt (37) to or in the operating or non-operating position;

wherein a first set of selector blades (203) of said at least one selector bit (201,202) meshes with teeth (35) of a selector set (9) if a relative rotation of the needle-holding needle cylinder (2) with respect to the drive cam (C) occurs in a first direction of rotation (CCW);

wherein the second set of selector blades (204) of the at least one selector bit (201,202) meshes with the teeth (35) of the selector set (9) if a relative rotation of the needle-holding cylinder (2) with respect to the drive cam (C) occurs in a second direction of rotation (CW) opposite to the first direction of rotation (CCW).

14. Method according to claim 13, wherein the circular knitting machine is manufactured according to claim 10, wherein if the needle-holding cylinder (2) is rotated in a first direction of rotation (CCW) relative to the drive cam (C), the first group of needle selectors (203) of the first selector head (201) acts on the selector set (9) to engage the butt (37) into the first pick point (300) and the take-off stitch at the yarn feeder (110), and the first group of needle selectors (203) of the second selector head (202) acts on the selector set (9) to engage the butt (37) into the second pick point (301) and the tuck stitch at the yarn feeder (110); wherein, if the needle-holding cylinder (2) rotates in a second needle rotation direction (CW) with respect to the drive cam (C), the second group needle selector (204) of the second selector head (202) acts on the selector group (9) to engage the butt (37) into the second needle starting point (301) and the drop stitch in a different adjacent yarn feeder (110), and the second group needle selector (204) of the first selector head (201) acts on the selector group (9) to engage the butt (37) into the first needle starting point (300) and the tuck stitch in said different adjacent yarn feeder (110).