WO2020212815A1

WO2020212815A1 - A circular knitting machine and a method for making terry stitches in a circular knitting machine

Info

Publication number: WO2020212815A1
Application number: PCT/IB2020/053437
Authority: WO
Inventors: Roberto RANZENIGO; Fabio Bonetti
Original assignee: Santoni S.P.A.
Priority date: 2019-04-16
Filing date: 2020-04-10
Publication date: 2020-10-22
Also published as: CN111826795B; TW202041737A; EP3956508A1; CN111826795A; EP3956508B1; IT201900005888A1

Abstract

A circular knitting machine comprises a plurality of knockover sinkers (7), each housed in a radial groove (6) and having a pin (13) configured for cooperating the needles (3) so as to manufacture a knitted fabric, a shaped sinker (8) placed beside each of the knockover sinkers (7), wherein the shaped sinker (8) is movable with respect to the respective knockover sinker (7) and independently from the respective knockover sinker (7), wherein the shaped sinker (8) has a nose (16) placed above the respective knockover sinker (7) and configured for making a terry stitch cooperating with a needle (3). A selector (10) is operatively coupled with each shaped sinker (8) and is oscillating in a radial plane between a rest position and an operating position, wherein in the operating position the selector (10) acts directly or indirectly upon the shaped sinker (8) so as to deviate the trajectory of the shaped sinker (8). A selecting actuator (26) can be engaged upon command with the selectors (10) and is configured for causing the selectors (10) to switch from the rest position to the operating position.

Description

DESCRIPTION

“A circular knitting machine and a method for making terry stitches in a circular knitting machine”

Field of the invention

The present invention relates to a circular knitting machine and to a method for making terry stitches in a circular knitting machine. In particular, the present invention relates to moving mechanisms for sinkers designed to make terry stitches. More particularly, the present invention relates to the structure of the elements actuating the sinkers designed to make terry stitches, by turning the relative rotational movement between the crown supporting the sinkers into given radial movements of the sinkers themselves. Preferably though not exclusively, the present invention relates to circular knitting machines configured for manufacturing fabrics with intarsia motifs (known as intarsia machines or argyle machines).

Background of the invention

As is known, circular knitting machines comprise a needle-holding element (needle-holding cylinder and/or plate) on which one or more series of needles are arranged along a circular path (circular needlebeds), and devices apt to control the movement of the needles for knitted fabric formation. Knockover sinkers are arranged in radial seats obtained in a ring-shaped body (sinker crown) arranged around the needle-holding cylinder, and said knockover sinkers cooperate with the needles of the needle-holding cylinder and/or of the needle-holding plate so as to make knitted fabric.

For particular designs, i.e. when carrying out relief motifs, it is known to make terry stitches, i.e. knitted curls with a given length, by means of a particular movement of some sinkers (anticipating the radial movement of the sinker towards the needles), which differs from the movement carried out when making plain stitches. To this purpose knockover sinkers are known, which have each a pin working for making plain stitches, as well as an upper spring, integral with the pin, working however for making terry stitches. The knockover sinker is made as one piece, and spring and pin are integral with one another and therefore move together.

For instance, public document M 12003A001995 discloses a device for selecting sinkers, comprising for each of the radial grooves housing the sinkers, a selector oscillating in a radial plane with respect to the sinker crown so as to switch between an operating position to a non-operating position or vice versa, which is connected to the corresponding sinker arranged in the corresponding radial groove, so as to induce a different actuation of the sinker depending on whether the selector is in the non-operating position or in the operating position. Moreover, a selecting actuator is provided, laterally facing the sinker crown and to be engaged upon command with the selector so as to switch it from the non-operating position to the operating position. When the selector is in the non-operating position, the selecting actuator does not intervene, the sinker is actuated by means of actuating cams only and follows a first path so as to cooperate with the needles for making plain stitches or however other than terry stitches. When the selector is switched to the operating position, the same sinker is pushed towards an axis of the sinker crown so as to engage and follow a different path defined by the actuating cams, Such a different path radially moves the knockover sinker towards said central axis in advance, with respect to the movement caused by the first path, so as to cooperate with the needles for making terry stitches.

A circular knitting machine configured for manufacturing fabrics with intarsia motifs (intarsia machine), conversely, is disclosed for instance in document EP1620590 issued to the same Applicant. Intarsia is a knitting technique enabling to obtain motifs using yarns of different colors in the same knitted course. Intarsia technique is usually used for creating multicolored motifs. As for woodworking technique, which it shares the name with, fields with different colors and materials seem to be fitted together as in a puzzle. Differently from other multicolor knitting techniques, there is only“active” color on a given stitch and the yarn is not moved to the reverse. When a color changes on a given row, the old yarn is left hanging.

Summary

In the framework of circular knitting machines as the ones disclosed above, the Applicant has identified the presence of some drawbacks.

First of all, the Applicant has observed that known machines as described above show little flexibility since the movements of the mechanisms designed for making terry stitches (springs) are necessarily firmly connected to the movements of the knockover sinkers, in particular of the pin of the knockover sinkers. As a result, the formation of terry stitches/curls with particular shaped/lengths is limited in that the radial travel of the springs is limited by structural constraints acting upon the travel of the sinker pins, or conversely, the formation of plain stitches is limited in that the radial travel of the pins is limited by structural constraints acting upon the sinker springs.

For instance, though not necessarily, if the machine is of a double needlebed type with an upper needle holding plate, the radial movement of the knockover sinkers as disclosed above can be limited by the presence of the springs since they obviously must not interfere with said needle-holding plate.

The Applicant has further observed that, in the known solutions disclosed above, the change in the shape of the springs so as to make different terry stitches necessarily involves the replacement of all the knockover sinkers, since they have said springs integrated therein, with subsequent high costs related to parts to be replaced and to the time required for the replacement.

Under these circumstances, an aim underlying the present invention, in its various aspects and/or embodiments, is first to propose a circular knitting machine enabling to manufacture knitted fabrics with complex terry stitches with the most different features.

A further aim of the present invention is to propose a circular knitting machine which is able to manufacture knitted fabrics with terry stitches and can be easily configured as a function of the features and positions of the terrycloth motif to be obtained on the fabric.

Another aim of the present invention is to propose a circular knitting machine which is able to manufacture knitted fabrics with terry stitches and is compact and relatively simple from a structural point of view as well as relatively cheap and easily maintained. A further aim of the present invention is to provide a circular knitting machine which is able to manufacture highly complex knitted fabrics with terry stitches in relatively short manufacturing times.

A further aim of the present invention is to provide a circular knitting machine which enables to manufacture knitted fabrics with complex terry stitches having the most different features without having to dramatically reconfigure the machine itself or parts of it.

A further aim of the present invention is to provide a circular knitting machine configured for manufacturing fabrics with intarsia motifs (intarsia machine or argyle machine), which is also able to manufacture knitted fabrics with terrycloths according to the aims listed above.

These and other possible aims, which shall appear better from the following description, are basically achieved by a circular knitting machine and by a method for making terry stitches in a circular knitting machine, according to one or more of the appended claims and according to the following aspects and/or embodiments, variously combined, possibly also with the aforesaid claims.

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

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

Some aspects of the invention are listed below.

In one aspect, the invention relates to a circular knitting machine for manufacturing terrycloth knitted fabric, comprising:

a needle-holding cylinder having a plurality of longitudinal grooves arranged around a central axis of the needle-holding cylinder;

a plurality of needles, each being housed in a respective longitudinal groove;

at least one yarn feed operatively associated to the needles;

a crown arranged around the needle-holding cylinder and having a plurality of radial grooves;

at least one guiding ring operatively associated to the crown, wherein the crown is rotatable with respect to the guiding ring and around the central axis;

a plurality of knockover sinkers, each housed in one of the radial grooves and radially movable in said radial groove, each knockover sinker having a pin configured for cooperating with the needles and a butt engaged with a first guide developing around the central axis; wherein the first guide is configured for moving the knockover sinker radially along the respective radial groove when the crown rotates with respect to the guiding ring and around the central axis;

a shaped sinker placed beside each of the knockover sinkers, wherein the shaped sinker is movable with respect to the respective knockover sinker and independently from the respective knockover sinker, wherein the shaped sinker has a spring placed above the respective knockover sinker, wherein the spring is configured for making a terry stitch in cooperation with a needle, wherein the shaped sinker has a butt that is or can be engaged with a second guide obtained in the guiding ring and developing around the central axis, wherein the second guide defines a plurality of trajectories for the shaped sinker, wherein the second guide is configured for moving the shaped sinker radially when the crown rotates with respect to the guiding ring and around the central axis;

a selector operatively coupled with said at least one shaped sinker, wherein the selector is movable, preferably oscillating, in a radial plane between a rest position and an operating position, wherein in the operating position the selector acts directly or indirectly upon said at least one shaped sinker so as to deviate the butt of the shaped sinker along a trajectory of the second guide;

at least one selecting actuator laterally facing the crown, fixed with respect to the guiding ring, that can be engaged under control with the selectors and is configured for causing the selectors to switch from the rest position to the operating position.

The Applicant has found out that the present invention enables to solve the problems listed above related to the prior art and thus to obtain the intended aims.

The Applicant has first found out that the invention enables to manufacture highly complex knitted fabrics with terry stitches in relatively short times.

The Applicant has further found out that the invention enables to manufacture knitted fabrics with terry stitches of various types and with the most different features. As a matter of fact, the invention enables to precisely select the shaped sinkers that are required for making the terry stitches to be obtained by activating or not the respective selectors. Moreover, since the shaped sinkers are independent with respect to the knockover sinkers, their movement and function are not limited and/or hindered by the presence and/or position and/or by the movements of said knockover sinkers. This allows e.g. to make on the knitted article some areas with terry stitches of a certain type and other areas with terry stitches of another type, and in the desired positions. The Applicant has also found out that the machine according to the invention is highly flexible since it allows to switch from manufacturing a type of knitted fabric with terry stitches to a different type in a fast and relatively simple manner, acting upon the selecting actuators.

Further aspects of the invention are listed below.

In one aspect, at least one motor is operatively connected to the needle-holding cylinder and to the crown so as to make them rotate around the central axis.

In one aspect, cams and/or other types of devices are arranged around the needle-holding cylinder so as to turn the rotational motion of the needle-holding cylinder into an axial motion of the needles.

In one aspect, the machine comprises a plurality of yarn feeds, preferably two or four thereof.

In one aspect, said at least one selecting actuator is placed on said at least one yarn feed, preferably on each yarn feed.

In one aspect, the circular knitting machine is an intarsia machine, i.e. a machine configured for manufacturing fabrics with intarsia motifs (known as intarsia machine or argyle machine).

In one aspect, the machine further comprises: a needle-holding plate exhibiting a plurality of radial grooves with respect to the central axis; a plurality of auxiliary needles, each housed in a respective radial groove of the needle-holding plate. In one aspect, the needle-holding plate rotates together with the needle-holding cylinder around the central axis, preferably by means of said motor.

In one aspect, cams are coupled with the needle-holding plate and guide the radial movement of the auxiliary needles of said needle-holding plate while said needle-holding plate rotates.

In one aspect, the needle-holding plate is placed above the needle-holding cylinder with a circumferential edge thereof placed near the needles of the needle-holding cylinder.

In one aspect, terminal ends of the auxiliary needles of the needle-holding plate and terminal ends of the needles of the needle-holding cylinder are placed close to one another so as to define a double needlebed of the machine.

In one aspect, the knockover sinkers are movable below the needle-holding plate.

In one aspect, the shaped sinkers are radially movable between a position at a distance from the needle holding plate and a position close to said needle-holding plate without interfering with said needle-holding plate. The movements of the knockover sinkers are not limited by the shaped sinkers. The knockover sinkers can radially get closer to the central axis, moving below the needle-holding plate, than the shaped sinkers which however limit their travel getting close to the needle-holding plate.

In one aspect, a knockover sinker, a shaped sinker and a selector define an assembly of flat parts housed in a respective groove. The radial groove houses the whole first assembly so as to reduce the overall size.

In one aspect, each knockover sinkers is operatively uncoupled from the selector. The selector does not interact with the knockover sinker and does not cause the movements thereof. The movement of the selector between the rest position and the operating position does not affect the movement of the respective knockover sinker.

In one aspect, the shaped sinker is a flat element, preferably made of metal.

In one aspect, each shaped sinker comprises a main body and the spring is arranged above the main body, when the shaped sinker is correctly installed in the machine.

In one aspect, the main body comprises a horizontal flat bar and a vertical flat upright developing from the horizontal flat bar, wherein the spring is arranged on an upper end of the flat upright.

In one aspect, the main body and spring lie in the same plane.

In one aspect, the butt of the shaped sinker is flat and extends vertically from the flat bar.

In one aspect, the butt of the shaped sinker is positioned on a radially outer end of the main body.

In one aspect, the butt of the shaped sinker points downwards.

In one aspect, the selector acts indirectly upon an end of the shaped sinker that is radially opposed to the spring.

In one aspect, the selector is a flat element, preferably made of metal.

In one aspect, the selector exhibits a base portion configured for oscillating around an axis tangent to a horizontal circumference with its center in the central axis.

In one aspect, the selector exhibits an abutment portion at a distance from the base portion, pointing towards the central axis and configured for indirectly acting upon the shaped sinker. In one aspect, the selector has at least one tooth radially pointing outwards, i.e. on the side opposed to the central axis, and configured for interacting with the selecting actuator.

In one aspect, the abutment portion of the selector is in a higher position than the abutment surface of the pushing unit.

In one aspect, the guiding ring comprises a circular track extending around the central axis.

In one aspect, each selector, preferably, the base portion of each selector, is slidingly engaged into the circular track so as to rotate together with said at least one shaped sinker.

In one aspect, the knockover sinker is a flat element, preferably made of metal.

In one aspect, the knockover sinker comprises a main body and the respective pin is arranged above the main body.

In one aspect, the main body lies basically in a plane.

In one aspect, the main body comprises a horizontal flat bar and a vertical flat upright developing from the horizontal flat bar, wherein the pin is arranged on an upper end of the flat upright.

In one aspect, the butt of the knockover sinker is flat and extends vertically from the flat bar.

In one aspect, the butt of the knockover sinker is placed on a radially outer end of the main body of the knockover sinker.

In one aspect, the butt of the knockover sinker points upwards.

In one aspect, when the knockover sinker is associated to the shaped sinker in the respective groove, the butt of the knockover sinker is radially placed between the butt and the spring of the shaped sinker.

In one aspect, the machine comprises a plurality of pushing units, each associated to a respective selector and to a respective shaped sinker.

In one aspect, in the operating position the selector rests against the pushing unit and the pushing unit is configured for pushing against the shaped sinker.

The use of the pushing units, which are operatively placed between the selectors and the shaped sinkers, allows the selectors to indirectly act upon the shaped sinkers.

In one aspect, the pushing unit is a flat element, preferably made of metal.

In one aspect, the guiding ring comprises a third guide extending around the central axis and defining a plurality of trajectories.

In one aspect, each pushing unit exhibits a butt that is or can be engaged with the third guide.

In one aspect, the pushing unit comprises a horizontal portion, preferably shaped as a horizontal flat bar, wherein the butt is positioned on a radially outer end of the horizontal flat bar.

In one aspect, the horizontal portion of the pushing unit partially vertically overlaps the shaped sinker.

In one aspect, the butt of the pushing unit is flat and extends vertically from the horizontal flat bar.

In one aspect, the butt of the pushing unit points upwards.

In one aspect, the pushing unit comprises a vertical portion arranged close to a radially outer end of the pushing unit and preferably pointing downwards.

In one aspect, the pushing unit exhibits an abutment surface facing a radially outer end of the shaped sinker. In one aspect, the abutment surface is basically counter-shaped to said radially outer end of the shaped sinker.

In one aspect, the abutment surface is supported by the vertical portion.

In one aspect, the vertical portion defined the abutment surface and the butt of said pushing unit.

In one aspect, the abutment surface is placed at a lower level than the horizontal portion and the butt develops upwards from the horizontal portion.

In one aspect, at least one part of the abutment surface is inclined with respect to the central axis and a lower portion of said at least one inclined part is closer to the central axis than an upper portion of said at least one inclined part.

In one aspect, at least one part of the radially outer end of the shaped sinker is inclined with respect to the central axis and a lower portion of said at least one inclined part is farther from the central axis than an upper portion of said at least one inclined part.

The inclined surface prevent the pushing unit from inclining and stopping when it is pushed by the selector.

In one aspect, the radially outer end of the shaped sinker is supported by the respective butt.

In one aspect, said at least one shaped sinker is housed in one of the radial grooves together with the respective knockover sinker.

In one aspect, the machine further comprises a separator arranged in the radial groove between the shaped sinker and the knockover sinker.

In one aspect, the separator is a plate lying outside a plane when it is not under stress. The separator prevents the shaped sinker from dragging the knockover sinker or vice versa.

In one aspect, said plate is inserted between the shaped sinker and the knockover sinker so as to deform and laterally push against the shaped sinker and against the knockover sinker. The plate eliminates or reduces possible vibrations of the shaped sinker and of the knockover sinker.

In one aspect, said at least one selecting actuator comprises at least one selecting lever movable between a first position, in which it lies at a distance from the selectors, and a second position, in which it interferes with the selectors moving in front of the selecting actuator when the crown rotates with respect to the guiding ring and around the central axis, so as to move the selectors from the rest position to the operating position.

In one aspect, the selecting actuator is of magnetic or piezoelectric type.

In one aspect, the first guide (for the knockover sinkers) is radially further inner with respect to the second guide.

In one aspect, the second guide (for the shaped sinkers) defines a radially outer trajectory, at least one radially inner trajectory, preferably a plurality of radially inner trajectories, and a plurality of connecting portions between the radially outer trajectory and said at least one radially inner trajectory.

In one aspect, the third guide defines a radially outer trajectory and at least one radially inner trajectory, preferably a plurality of radially inner trajectories, having opposed ends connected to the radially outer trajectory. In one aspect, said at least one radially inner trajectory is a curve getting closer to the central axis and then away from the central axis.

In one aspect, the second guide is radially further inner with respect to the radially outer trajectory of the third guide.

In one aspect, the circular track is radially further outer with respect to the third guide.

In one aspect, the selecting actuator is placed on said at least one radially inner trajectory so as to deviate the pushing units in said radially inner trajectory.

In one aspect, the selecting actuator is placed on at least one of the connecting portions of the second guide so that the shaped sinkers are deviated in said connecting portion by the pushing units moving in the radially inner trajectory of the third guide.

In one aspect, two radially inner trajectories of the third guide are arranged symmetrically with respect to a selecting actuator, so as to allow the machine to work both in clockwise and in counterclockwise direction.

In one aspect, two connecting portions of the second guide are arranged symmetrically with respect to a selecting actuator, so as to allow the machine to work both in clockwise and in counterclockwise direction.

In one aspect, the present invention also relates to a method for manufacturing knitted fabric, in particular for making terry stitches, using a machine according to one or more of the preceding aspects.

In one aspect, the method comprises: keeping the selectors in the rest position, while the crown rotates with respect to the guiding ring and around the central axis, either in a clockwise or counterclockwise direction, so as to move the shaped sinkers along the radially outer trajectory of the second guide, the knockover sinkers moving along the first guide, so as to make a plain knitted fabric.

In one aspect, while the selectors are in the rest position, the pushing units move along the radially outer trajectory of the third guide and the pushing units are radially at a distance from the respective shaped sinkers.

In one aspect, the method comprises: engaging said at least one selecting actuator with at least one of the selectors so as to move said at least one selector in the operating position for at least one rotational portion of the crown around the central axis, either in a clockwise or counterclockwise direction, so as to move said at least one shaped sinker associated to said at least one selector on the radially inner trajectory of the second guide and move the spring towards the central axis for at least one rotational portion of the crown around said central axis, so that the spring of the shaped sinker makes a terry stitch in the knitted fabric by cooperating with at least one pair of needles.

Further characteristics and advantages shall be more evident from the detailed description of a preferred embodiment of a circular knitting machine and of a method for manufacturing knitted fabric according to the present invention.

Description of the drawings

This description shall be made below with reference to the accompanying drawings, provided to a merely indicative and therefore non-limiting purpose, in which: Figure 1 shows a portion of a circular knitting machine according to the present invention with some parts removed for better showing others;

Figure 2 shows the portion of Figure 1 with other parts removed for better showing other elements of the machine as in the preceding figures;

Figure 3 shows a different, partially sectioned view of the portion of Figure 1;

Figure 3A is a magnified portion of Figure 3;

Figure 3B is a sectioned view of the portion of Figure 3 associated to a needle-holding plate;

Figure 4 shows an exploded view of an assembly of elements belonging to the machine as in the preceding figures, which can be seen in Figure 3;

Figure 5 shows the elements of the exploded view of Figure 4 associated to one another;

Figure 6 is a plan view of guiding cams of the circular machine as in the preceding figures, with some trajectories in evidence;

Figure 7 is the view of Figure 6 with other trajectories in evidence;

Figures 8 - 10 show the cams of Figures 7 and 8, in which respective operating steps of the machine according to the invention are pointed out in a schematic manner.

Detailed description

With reference to the figures mentioned, the numeral 1 globally designates a portion of a knitting head of a circular knitting machine according to the present invention. The circular knitting machine shown is for instance a machine configured for manufacturing fabrics with intarsia motifs (known as intarsia machine or argyle machine). The circular knitting machine comprises a basement, not shown since it is of known type, constituting the supporting structure of the machine, and said knitting head 1 is mounted onto the basement. The knitting head 1 is equipped with a needle-holding cylinder 2, with a plurality of needles 3 mounted onto the needle-holding cylinder 2, and with control means, not shown, apt to selectively actuate the needles 3 so as to enable the production of a fabric. The needle-holding cylinder 2 is usually mounted in vertical position onto the basement, with the needles 3 arranged vertically and protruding beyond an upper edge of the needle-holding cylinder 2.

As is known, the needle-holding cylinder 2 has a plurality of longitudinal grooves 4 obtained on a radially outer surface of the needle-holding cylinder 2. The longitudinal grooves 4 are arranged around a central axis“X-X” (vertical) of the needle-holding cylinder 2 and develop parallel to said central axis“X-X”. Each longitudinal groove 4 houses a respective needle 3 and a respective drive chain comprising a plurality of flat parts. Actuating cams are arranged as a casing around the cylinder 2 and lie facing the radially outer surface of the needle-holding cylinder 2 and thus the longitudinal grooves 4 and the drive chains. These actuating cams are defined e.g. by plates and/or grooves arranged on an inner surface of the casing.

In one embodiment, the casing of the actuating cams is basically stationary, whereas the needle-holding cylinder 2 rotates (with a continuous or alternating motion in both directions) around the central axis“X-X” by means of a suitable motor, so as to generate a relative rotational motion between the drive chains and the actuating cams and turn the rotational motion of the needle-holding cylinder 2 into an axial motion of the needles 3 in order to manufacture knitted fabric by means of the said needles 3.

The machine further comprises a crown 5 arranged around the needle-holding cylinder 2 and having a plurality of radial grooves 6 that are open above and on a radially inner edge of the crown 5, i.e. towards the central axis“X-X”. The grooves 6 shown in Figure 1 can also be obtained in an upper edge of the needle holding cylinder 2.

The crown 5 integral with the needle-holding cylinder 2 is moved in rotation around the central axis“X-X”, e.g. by means of the same motor referred to above.

Suitable devices, not shown, feed the yarns to be knitted on one or more yarn feeding points (known as feeds) usually arranged above the needle-holding cylinder 2. The circular knitting machine shown comprises a yarn feed configured for working with the needles 3 arranged along a circumference by means of a rotational motion of the needles 3 around the central axis“X-X”.

Each of the radial grooves 6 houses an assembly made up of a plurality of metal flat parts that can slide radially in the respective radial groove 6 and also one with respect to the other.

This assembly, better shown in Figures 4 and 5, comprises a knockover sinker 7, a shaped sinker 8, a pushing unit 9 associated with the shaped sinker 8, and a selector 10 for the pushing unit 9. Furthermore, a separator 11 is arranged in a stationary manner in the radial groove 6 between the shaped sinker 8 and the knockover sinker 7. The separator 11 is an elastic plate lying outside a plane when it is not under stress, and pushing laterally against the shaped sinker 8 and the knockover sinker 7 so as to limit the vibrations thereof. The separator 11 further prevents the shaped sinker 8 from dragging the knockover sinker 7, or vice versa, in the respective motion along a radial direction.

The knockover sinker 7 comprises a main body 12 defined by a horizontal flat bar and a vertical flat upright developing from the horizontal flat bar. A pin 13 is arranged on an upper end of the flat upright and above the main body 12. The pin 13 is configured for cooperating with the needles 3 when making a plain knitted fabric. A butt 14 of the knockover sinker 7 is placed on a radially outer end of the main body 12 of the knockover sinker 7 and extends vertically upwards from the flat bar.

The shaped sinker 8 comprises a main body 15 defined by a horizontal flat bar and a vertical flat upright developing from the horizontal flat bar. A protrusion shaped as a spring 16 or a horn is arranged on an upper end of the flat upright, i.e. above the main body 12, extends and projects towards the main axis“X-X” and lies in the same plane as said main body 12. A butt 17 extending vertically from the flat bar downwards is arranged on a radially outer end of the main body 12 of the shaped sinker 8.

The pushing unit 9 comprises a horizontal portion 18 shaped as a horizontal flat bar, and a butt 19 positioned on a radially outer end of its horizontal flat bar. The butt 19 of the pushing unit 9 extends vertically from the horizontal flat bar upwards. The pushing unit 9 further comprises a vertical portion 20 arranged close to the radially outer end of said pushing unit 9 and pointing downwards.

When the metal parts described above are correctly housed in the respective radial groove 6, the knockover sinker 7 lies beside the shaped sinker 8 and the separator 11 is placed between them. The butt 14 of the knockover sinker 7 is radially placed between the butt 19 and the spring 16 of the shaped sinker 8. The horizontal portion of the pushing unit 9 partially overlaps vertically the shaped sinker 8, in particular the main body 15 of the shaped sinker 8.

The butt 17 of the shaped sinker 8 basically lies parallel to the vertical portion 20 of the pushing unit 9 (Figures 2, 3 and 5). In particular, an edge of the vertical portion 20 of the pushing unit 9 pointing towards the butt 17 defined an abutment surface 21. This abutment surface 21 faces the radially outer end of the shaped sinker, i.e. an edge 22 of the butt 17 of the shaped sinker 8, and is basically countershaped to said butt 22 of the butt 17 of the shaped sinker 8 (Figure 3A).

As can be better seen in Figure 3A, a part of the abutment surface 21 is inclined with respect to the central axis“X-X” and a lower portion of said at least one inclined part is closer to the central axis“X-X” than an upper portion of said at least one inclined part. Vice versa, a part of the edge 22 of the radially outer end of the shaped sinker 8 is inclined with respect to the central axis“X-X” and a lower portion of said at least one inclined part is closer to the central axis“X-X” than an upper portion of said at least one inclined part.

The selector 10 has an elongated shape along a basically vertically direction. The selector 10 has a base portion 23 with a bow-shaped profile, configured for oscillating around an axis tangent to a horizontal circumference with its center in the central axis“X-X”. The selector 10 exhibits an abutment portion 24 at a distance from the base portion 23, pointing towards the central axis“X-X” and configured for indirectly acting upon the shaped sinker 8 through the pushing unit 9. In particular, the abutment portion 24 faces the vertical portion 20 of the pushing unit 9.

The selector 10 has a tooth 25 radially pointing outwards, i.e. on the side opposed to the central axis“X-X”, and configured for interacting with a selecting actuator 26 described below.

The knockover sinker 7 is operatively uncoupled from the selector 10, i.e. the selector 10 does not interact with the knockover sinker 7 and does not cause movements thereof. The shaped sinker 8 is movable with respect to the respective knockover sinker 7 and in an independent manner from the respective knockover sinker 7.

The butt 14 of the knockover sinker 7 and the butt 19 of the pushing unit 9 are/can be engaged in guides obtained in an upper guiding ring, whereas the butt 17 of the shaped sinker 8 and the vertical portion 20 of the pushing unit 9 are/can be engaged in guides obtained in a lower guiding ring. The upper and lower guiding rings are stationary and operatively associated with the crown 5, and the crown 5 is rotatable, together with the needle-holding cylinder 2, with respect to the guiding rings and around the central axis“X-X”.

The lower guiding ring has a circular track 27 (Figure 6) extending around the central axis“X-X”. The base portion 23 of each selector 10 is slidingly engaged in the circular track 27 so as to rotate together with the respective shaped sinker 8 around the central axis“X-X”.

The upper guiding ring has a first guide 28 developing, around the central axis“X-X”. The butt 14 of the knockover sinker 7 is slidingly engaged with said first guide 28, which is configured for radially moving the knockover sinker 7 along the respective radial groove when the crown 5 with the knockover sinkers 7 rotates with respect to the guiding rings and around the central axis“X-X”. The lower guiding ring has (Figure 7) a second guide 29 developing around the central axis“X-X” in a radially further outer with respect to the first guide 28 and radially further inner with respect to the circular track 27. The butt 17 of the shaped sinker 8 is slidingly engaged with said second guide 29. The second guide 29 is configured for radially moving the shaped sinker 8 radially along the respective radial groove when the crown 5 with the shaped sinkers 8 rotates with respect to the guiding rings and around the central axis“X-X”. The second guide 29 defines a plurality of trajectories for the shaped sinker 8. In particular, the second guide 29 defines a circular, radially outer trajectory 30, a pair of radially inner trajectories 31, each of which develops on an arc of circle, and a pair of connecting portions between the radially outer trajectory 30 and the two radially inner trajectories 31.

The upper guiding ring has a third guide 32 (Figure 6) extending around the central axis“X-X”, and the butt 19 of each pushing unit 9 is engaged with the third guide 32. The third guide 32 defines a circular, radially outer trajectory 33, which lies radially placed between the circular path 27 and the second guide 29, and a pair of radially inner trajectories 34 having opposed ends connected to the radially outer trajectory 33. As can be seen in Figure 6, each of the radially inner trajectories 34 is a curve getting closer to the central axis“X-X” and then away from the central axis“X-X”.

The selector 10 is oscillating in a radial plane between a rest position and an operating position, wherein in the operating position the selector 10 acts, by means of the pushing unit 9, upon the respective shaped sinker 8 so as to deviate the butt 17 of the shaped sinker 8 from the radially outer trajectory 30 of the second guide 29 of the radially inner trajectory 31. In particular, in the operating position the selector 10 rest against the pushing unit 9 and the pushing unit 9 by means of its butt 19 is deviated from the radially outer trajectory 33 of the third guide 32 in one of the radially inner trajectories 34 and pushes against the shaped sinker 8.

To this purpose, the machine according to the non-limiting embodiment shown comprises one selecting actuator 26 which laterally faces the crown 5, is stationary with respect to the guiding rings and can be engaged upon command with the selectors 10. The selecting actuator 26 is configured for causing the selectors 10 to switch from the rest position to the operating position.

The selecting actuator 26 (Figures 2, 3 and 3A) is of magnetic or piezoelectric type and comprises a plurality of levers 35 arranged one above the other and movable between a first position, e.g. a raised position, and a second position, e.g. a lowered position. In the first position, the levers 35 lie at a distance from the teeth 25 of the selectors 10 so as not to interfere with said teeth 25 when the selectors 10 are in their rest positions. In particular, in the first position said teeth 25 are positioned between the levers 35. In the second position, the levers 35 interfere with the teeth 25 of the selectors 10 moving in front of the selecting actuator 26 when the crown 5 rotates with respect to the guiding rings and around the central axis“X-X”, so as to move the selectors 10 from the rest position to the operating position.

An electronic control unit, not shown, is operatively connected to the motor or motors causing the rotation of the needle-holding cylinder 2 and of the crown 5, to the selecting actuators 26 and to further actuating units, if any, of the machine. The electronic control unit is configured/programmed for commanding the motor or motors and the selecting actuators 26 and said further actuating units, if any, of the machine. In particular, the electronic control unit is configured/programmed for selectively moving the levers 35 of the selecting actuators 26 so as to move the selectors 10 singularly from the rest position to the operating position.

The pair of radially inner trajectories 31 of the second guide 29 and the pair of radially inner trajectories 34 of the third guide 32 are arranged symmetrically with respect to the only one selecting actuator 26. In particular, two connecting portions of the second guide 29 are arranged symmetrically with respect to said selecting actuator 26. This layout allows the machine to work both in clockwise and in counterclockwise direction. The selecting actuator 26 is thus placed on the two radially inner trajectories 34 of the third guide 32 and on the two connecting portions of the second guide 29 so as to deviate the pushing units 9 in one of the two radially inner trajectories 34 of the third guide 32 and therefore deviate the shaped sinkers 8 in one of the two radially inner trajectories 31 of the second guide 29 depending on the direction of rotation.

The machine shown further comprises (Figure 3B) a needle-holding plate 36 exhibiting a plurality of radial grooves 37 extending radially with respect to the central axis“X-X”, and a plurality of auxiliary needles 38, each housed in a respective radial groove 37 of the needle-holding plate 36. The needle-holding plate 36 is placed above the needle-holding cylinder 2 with a circumferential edge thereof placed near the needles 3 of the needle-holding cylinder 2. In an operating position of the needle-holding plate 36, terminal ends of the auxiliary needles 38 and terminal ends of the needles 3 are placed close to one another so as to define a double needlebed of the machine. The needle-holding plate 36 can be moved away from the needles 3 of the needle-holding cylinder 2 by lifting it with suitable actuating devices, not shown, and brought to a non operating position.

The needle-holding plate 36 rotates together with the needle-holding cylinder 2 around the central axis“X-X”, preferably by means of said motor. Cams, not shown, are coupled with the needle-holding plate 36 and guide the radial movement of the auxiliary needles 38 of the needle-holding plate 36 while said needle-holding plate 36 rotates around the central axis“X-X”.

In use and according to the method of the present invention, in order to manufacture a plain knitted fabric (Figure 8), while the needle-holding cylinder 2 rotates with respect to the casing and the crown 5 rotates with respect to the guiding rings and around the central axis“X-X”, the levers of the selecting actuators 26 are kept in the first position in which they do not interfere with the teeth 25 of the selectors 10, which are therefore all in their respective rest positions. The butts 19 of the pushing units 9 go along the radially outer trajectory 33 of the third guide 32.

The butts 17 of the shaped sinkers 8 go along the radially outer trajectory 30 of the second guide 29, and therefore the springs 16 of the respective shaped sinkers 8 remain in a position radially at a distance from the central axis“X-X”, i.e. in a retracted or rest (non-operating) position in which they do not interact with the yarn making the stitch.

The butts 14 of the knockover sinkers 7 follow the first guide 28 causing a radial movement of the knockover sinkers 7. The knockover sinkers 7 move forward and backward along respective radial directions so that the pins 13 cooperate with the needles 3, in a manner known per se and not further described here, and if required, with the auxiliary needles 38 for making a plain stitch. This operating mode can be implemented while the needle-holding cylinder 2, the crown 5 and the needle-holding plate 36 rotate in clockwise or counterclockwise direction.

As can be noticed by observing Figure 3B, the knockover sinkers 7 can work with the needles 3 and with the auxiliary needles 38 while the needle-holding plate 36 is in its operating position and the shaped sinkers 8 remain in the position at a radial distance from the central axis“X-X” and do not interfere with the needle holding plate 36. As a matter of fact, the knockover sinkers 7 are movable below the needle-holding plate 36 without interfering with said needle-holding plate 36.

In order to make terry stitches in the knitted fabric (Figures 9 and 10), the control unit commands the actuating devices of the needle-holding plate 36 so as to bring it to its non-operating, raised position. The control unit commands the selecting actuators 26 so that they move the levers 35 from the first to the second position and then vice versa in programmed angular positions of the needle-holding cylinder 2 and of the crown 5, so as to intercept specific selectors 10 associated with specific shaped sinkers 8. Referring for the sake of simplicity to a single selector 10 being intercepted, it is moved to the operating position in which the respective abutment portion 24 is moved towards the central axis“X-X”, while it rotates in counterclockwise direction with respect to the guiding rings, as schematically shown in Figure 9. The butt 19 of the pushing unit 9 is deviated in the radially inner trajectory 34 of the third guide 32 placed directly downwards from the selecting actuator 26, and follows it (Figure 9) pushing in its turn radially the respective shaped sinker 8.

The butt 19 and the pushing unit 9 then get back to the circular, radially outer trajectory 33 of the third guide 32 and push the respective selector 10 (Figure 9) backwards.

The butt 17 of the shaped sinker 8 (Figure 10) is moved from the radially outer trajectory 30 of the second guide 29 to the radially inner trajectory 31, so that the shaped sinker 8 is radially moved towards the central axis“X-X”. Then the butt 17 of the shaped sinker 8 is brought back to the radially outer trajectory 30 of the second guide 29 by a cam (Figure 10) and the shaped sinker 8 is thus pushed backwards again. By means of the radial movement of the shaped sinker 8 as described, the spring 16 cooperates with the needles 3 suitably moved by the respective cams (in a manner known per se and not further described here) so as to make a terry stitch in the knitted fabric. This operating mode can be implemented while the crown 5 rotates in counterclockwise direction, as in Figure 9 and 10, or in clockwise direction.

The present invention achieves important advantages both from a structural and a functional point of view.

As a matter of fact, by programming the control unit commanding the selecting actuators it is easily possible to make the desired selectors operating and thus manufacture complex terrycloth knitted fabrics with the most different features.

In particular, the structure of the machine according to the invention allows to make terry stitches basically anywhere on the fabric thus manufactured.

The simultaneous presence of shaped sinkers, for making terry stitches, and of traditional knockover sinkers placed beside the shaped sinkers, allows to manufacture plain and terry knitted fabric on the same machine with high flexibility. The independence of the knockover sinkers with respect to the shaped sinkers for terrycloth further enables to work with the auxiliary plates of the needle-holding plate for manufacturing plain knitted fabric, without any limitations due to the possible interference of the plate with the shaped sinkers. For instance, only shaped sinkers can be replaced by others with different features for making different terry stitches (curls).

The machine according to the invention further allows to make terry stitches and also other types of motifs with high speeds, thus dramatically reducing manufacturing times for even complex and sophisticated tubular knitted fabrics.

The control elements of the shaped sinkers 8 are such as to allow said sinkers to be placed very close to one another and thus to obtain a compact machine. As a matter of fact, since the selectors 10 do not act directly upon the shaped sinkers 8 but do so by deviating the trajectories of the pushing units 9, which in their turn push the shaped sinkers 8, the selectors 10 and also the selecting actuators 26 can be kept at a radial distance from the needles 3 and from the area where the stitch is formed, and the shaped sinkers 8 and the knockover sinkers 7 can be moved circumferentially close to one another.

Such a machine is further relatively simple from a structural point of view and thus of easy maintenance. Moreover, since many elements are similar or identical (pushing units, selectors, knockover sinkers and shaped sinkers) their manufacturing costs can be kept low, which positively affects the manufacturing costs of the machine as a whole.

Claims

1. A circular knitting machine for manufacturing terrycloth knitted fabric, comprising:

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

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

- at least one yarn feed operatively associated to the needles (3);

- a crown (5) arranged around the needle-holding cylinder (2) and having a plurality of radial grooves (6);

- at least one guiding ring operatively associated to the crown (5), wherein the crown (5) is rotatable with respect to the guiding ring and around the central axis (X-X);

a plurality of knockover sinkers (7), each housed in one of the radial grooves (6) and radially movable in said radial groove (6), each knockover sinker (7) having a pin (13) configured for cooperating with the needles (3) and a butt (14) engaged with a first guide (28) developing around the central axis (X-X); wherein the first guide (28) is configured for moving the knockover sinker (7) radially along the respective radial groove (6) when the crown (5) rotates with respect to the guiding ring and around the central axis (X-X);

a shaped sinker (8) placed beside each of the knockover sinkers (7), wherein the shaped sinker (8) is movable with respect to the respective knockover sinker (7) and independently from the respective knockover sinker (7), wherein the shaped sinker (8) has a spring (16) placed above the respective knockover sinker (7), wherein the spring (16) is configured for making a terry stitch in cooperation with a needle (3), wherein the shaped sinker (8) has a butt (17) that is or can be engaged with a second guide (29) obtained in the guiding ring and developing around the central axis (X-X), wherein the second guide (29) defines a plurality of trajectories for the shaped sinker (8), wherein the second guide (29) is configured for moving the shaped sinker (8) radially when the crown (5) rotates with respect to the guiding ring and around the central axis (X-

X);

a selector (10) operatively coupled with said at least one shaped sinker (8), wherein the selector (10) is movable, preferably oscillating, in a radial plane between a rest position and an operating position, wherein in the operating position the selector (10) acts directly or indirectly upon said at least one shaped sinker (8) so as to deviate the butt (17) of the shaped sinker (8) along a trajectory of the second guide (29);

at least one selecting actuator (26) laterally facing the crown (5), fixed with respect to the guiding ring, that can be engaged under control with the selectors (10) and is configured for causing the selectors (10) to switch from the rest position to the operating position.

2. The machine according to claim 1, wherein each knockover sinker (7) is operatively uncoupled from the selector (10).

3. The machine according to claim 1 or 2, wherein each selector (10) is slidingly engaged in a circular track (27) obtained in the guiding ring and extending around the central axis (X-X) so as to rotate with said at least one shaped sinker (8).

4. The machine according to one of the claims 1 to 3, comprising a plurality of pushing units (9), each associated to a respective selector (10) and to a respective shaped sinker (8); wherein in the operating position the selector (10) rests against the pushing unit (9) and the pushing unit (9) is configured for pushing against the shaped sinker (8).

5. The machine according to claim 4, wherein the pushing unit (9) has a butt (19) that is or can be engaged with a third guide (32) obtained in the guiding ring, extending around the central axis (X-X) and defining a plurality of trajectories.

6. The machine according to claim 4 or 5, wherein the pushing unit (9) has an abutment surface (21) facing a radially outer end of the shaped sinker (8); wherein the abutment surface (21) is basically counter-shaped to said radially outer end of the shaped sinker (8).

7. The machine according to claim 6, wherein at least one part of the abutment surface (21) is inclined with respect to the central axis (X-X) and a lower portion of said at least one inclined part is closer to the central axis (X-X) than an upper portion of said at least an inclined part.

8. The machine according to claim 7, wherein the selector (10) has a base portion (23) configured for oscillating around an axis tangent to a horizontal circumference with its center in the central axis (X-X) and an abutment portion (24) at a distance from the base portion (23), pointing towards the central axis (X-X) and configured for resting against the pushing unit (9).

9. The machine according to claim 8, wherein the abutment portion (24) is in a higher position than the abutment surface (21).

10. The machine according to one of the claims 7 to 9, wherein the pushing unit (9) has a horizontal portion

(18) partially vertically superimposed with respect to the shaped sinker (8), and a vertical portion (20) arranged at a radially outer end of the pushing unit (9) and defining the abutment surface (21) and the butt

(19) of said pushing unit (9).

11. The machine according to claim 10, wherein the abutment surface (21) is placed at a lower level than the horizontal portion (18) and the butt (19) develops upwards from the horizontal portion (18).

12. The machine according to one of the claims 1 to 11, wherein said at least one shaped sinker (8) is housed in one of the radial grooves (6) together with the respective knockover sinker (7); the machine further comprising a separator (11) arranged in the radial groove (6) between the shaped sinker (8) and the knockover sinker (7).

13. The machine according to claim 12, wherein the separator (11) is a plate lying outside a plane when it is not under stress; wherein said plate is inserted between the shaped sinker (8) and the knockover sinker (7) so as to laterally push against the shaped sinker (8) and against the knockover sinker (7).

14. The machine according to one of the claims 1 to 13, wherein said at least one selecting actuator (26) comprises at least one selecting lever (35) movable between a first position, in which it lies at a distance from the selectors (10), and a second position, in which it interferes with the selectors (10) moving in front of the selecting actuator (26) when the crown (5) rotates with respect to the guiding ring and around the central axis (X-X), so as to move the selectors (10) from the rest position to the operating position.

15. The machine according to one of the claims 1 to 14, wherein the first guide (28) is radially further inner with respect to the second guide (29); wherein the second guide (29) defines a radially outer trajectory (30), at least one radially inner trajectory (31) and a plurality of connecting portions between the radially outer trajectory (30) and said at least one radially inner trajectory (31).

16. The machine according to claim 5 or according to one of the claims 6 to 15 when depending on claim 5, wherein the third guide (32) defines a radially outer trajectory (33) and at least one radially inner trajectory (34) having opposed ends connected to the radially outer trajectory (33).

17. The machine according to claim 16, wherein the second guide (29) is radially further inner with respect to the radially outer trajectory (33) of the third guide (32).

18. The machine according to claim 3, wherein the circular track (27) is radially further outer with respect to the third guide (32).

19. The machine according to one of the preceding claims, further comprising:

a needle-holding plate (36) having a plurality of radial grooves (37) with respect to the central axis (X-

X);

- a plurality of auxiliary needles (38), each being housed in a respective radial groove (37) of the needle holding plate (36);

wherein the needle-holding plate (36) is placed above the needle-holding cylinder (2) with a circumferential edge thereof placed near the needles (3) of the needle-holding cylinder (2); wherein the knockover sinkers (7) are movable below the needle-holding plate (36); wherein the shaped sinkers (8) are radially movable between a position at a distance from the needle-holding plate (36) and a position close to said needle holding plate (36) without interfering with the latter.

20. A method for manufacturing knitted fabric using a machine according to one or more of the claims 1 to 19, wherein the method comprises: keeping the selectors (10) in the rest position, while the crown (5) rotates with respect to the guiding ring and around the central axis (X-X), so as to move the shaped sinkers (8) along the radially outer trajectory (30) of the second guide (29), the knockover sinkers (7) moving along the first guide (28), so as to make a plain knitted fabric; wherein, while the selectors (10) are in the rest position, the pushing units (9) move along the radially outer trajectory (33) of the third guide (32); wherein the pushing units (10) are radially at a distance from the respective shaped sinkers (8).

21. The method for manufacturing knitted fabric using a machine according to one or more of the claims 1 to 19, wherein the method comprises: engaging said at least one selecting actuator (26) with at least one of the selectors (10) so as to move said at least one selector (10) in the operating position for at least one rotational portion of the crown (5) around the central axis (X-X), so as to move said at least one shaped sinker (8) associated to said at least one selector (10) on the radially inner trajectory (31) of the second guide (29) and move the spring (16) towards the central axis (X-X) for at least one rotational portion of the crown (5) around said central axis (X-X), so that the spring (16) of the shaped sinker (8) makes a terry stitch in the knitted fabric by cooperating with at least one pair of needles (3).