A kit comprising a knitting machine with removable inserts, and method

Abstract

The kit comprises: a needle cylinder (2), forming part of a single bed, single-cylinder knitting machine (1); a set of inserts (13) that can be fixed to the head end of the cylinder (2) in special radial grooves (11) and which cooperate with radially movable elements (51), sliding in radial guide grooves (53) located outside the cylinder (2). In addition to the inserts (13) and movable elements (51), the kit comprises a series of sinkers (101), which can be used as an alternative to the inserts (13) and movable elements (51), as a function of the type of knitted fabric to be to obtained.

Description

A KIT COMPRISING A KNITTING MACHINE WITH REMOVABLE INSERTS,AND METHODDESCRIPTIONTECHNICAL FIELD

[0001] The present invention relates to single-cylinder knitting machines and more specifically to single-cylinder knitting machines with latch needles.BACKGROUND ART

[0002] Single-cylinder knitting machines are equipped with a single cylindrical needle bed formed by sliding needles in sliding or guide grooves formed in a needle cylinder. To form the stitch, the needles cooperate with a ring of sinkers provided with a reciprocating radial movement synchronized with the lifting and lowering movement of the needles.

[0003] Circular knitting machines have also been developed without sinkers or equipped with fixed sinkers, for example made on the upper end of the needle cylinder.

[0004] In machines without sinkers or in machines with fixed sinkers, the stitch is formed on a knock-over level or surface, also called stitch-forming surface, consisting of inserts fixed to the upper end of the needle cylinder, i.e., to the end at which the needle hooks are arranged, which are cyclically extracted and retracted to engage with the yarn and form the stitches.

[0005] Knitting machines without sinkers are disclosed in EP3268526, EP2906743 and EP2108725.

[0006] EP2906743 discloses a single bed circular knitting machine, i.e., a singlecylinder knitting machine, comprising a needle cylinder and a plurality of latch needles sliding in respective grooves of the needle cylinder. Along one end of the needle cylinder, an annular channel with an undercut is advantageously formed. Between adjacent needle sliding grooves, a respective substantially radial groove is provided, formed in the needle cylinder and intersecting the annular channel. Each groove houses a respective insert. The various inserts form, with respective upper edges, a stitchforming surface or plane, i.e., a knock-over plane. Each insert can have an appendage that inserts into the undercut of the annular channel to be locked therein. A locking element locks the inserts in a working position in the respective grooves. In the working position, the insert appendages are advantageously pushed into the undercut of the annular channel by the locking element, thus keeping the inserts still during the knitting process, preventing the inserts from slipping out of the grooves. By removing or deactivating the locking element, one or more inserts can be removed and replaced, for example because worn or damaged.

[0007] EP3268526 discloses a single bed machine, i.e., a single cylinder machine, without sinkers, in which the inserts are formed by shaped plates, which hook onto the upper end of the needle cylinder due to elastic deformation. For this purpose, each insert has an S-shaped elastic appendage that engages with an inner annular surface of the needle cylinder. A similar solution, with a differently shaped appendage, is disclosed in EP2108725.

[0008] These systems of interchangeable inserts are particularly efficient, but can have some difficulties in the production of certain types of fabrics, in particular when elaborate knitting patterns are required, such as pique, double pique, two-ply fleece with insertion of elastic thread, or even when plain fabric is to be produced with a very wide or very narrow stitch.

[0009] There is therefore a need to improve single bed knitting machines without sinkers and the relative interchangeable inserts, to achieve higher efficiency.SUMMARY

[0010] The problems and limitations of the prior art are overcome or alleviated by a kit according to claim 1 and a method according to claim 25.

[0011] Preferred embodiments and further advantageous features are described below and defined in the attached dependent claims.

[0012] According to another aspect, a cylinder for a single bed circular knitting machine is disclosed herein, comprising an outer lateral surface, an inner lateral surface and a head end; wherein on the outer lateral surface are arranged sliding grooves for a plurality of needles, parallel to an axis of the needle cylinder; wherein on the head endof the needle cylinder, between each pair of adjacent sliding grooves, a respective radial groove is provided; and wherein the needle cylinder comprises a needle cylinder body and a removable annular element, forming the head end of the needle cylinder and on which the radial grooves are formed.

[0013] A single bed circular knitting machine comprising a cylinder as defined above is also described. Advantageously, inserts can be inserted into the radial grooves of the cylinder, which cooperate with movable stitch forming elements, the inserts defining a stitch forming plane. The use of a removable annular element allows for quick repair of the machine or cylinder in the event of damage to the radial grooves or in general to the head surface of the needle cylinder.

[0014] Further advantageous features of the needle cylinder and the machine that uses it are defined in the attached claims and described with reference to the attached drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention will be better understood by following the description and the attached drawings, which illustrate exemplary and non-limiting embodiments of the invention. More in particular, the drawings show:Fig. 1 and 2 two sections, according to a radial plane, of a head portion of a portion of a single bed circular knitting machine with a needle cylinder, in two distinct working positions;Fig. 1 A a section similar to the section of Figs. 1 and 2 in an embodiment variant;Fig. 3 a section similar to the section of Figs. 1 and 2, with an insert removed from the groove thereof;Fig. 3 A an enlarged axonometric view of the insert of Fig. 3;Fig. 4 a section similar to the section of Fig. 1, with an insert removal tool in working position;Fig. 5 and 6 a side view and an axonometric view of an insert in a different embodiment;Fig. 7 an axonometric view of an insert in a further embodiment;Fig. 8 a side view of a modified embodiment of the insert;Figs. 9 and 10 a comparison between the machine setup comprising the inserts of Fig. 6 and the knitting elements cooperating therewith and the setup with replacement sinkers;Fig. 11 and 12 a sequence of movements of the needles and of the elements cooperating with the inserts in the configuration of a machine setup with the inserts of Fig. 6;Fig. 13 and 14 a sequence of movements of the needles and sinkers when the machine is set up with the sinkers replacing the inserts and the movable elements cooperating with the inserts to form the stitch;Fig. 15 is a sectional view similar to the view of Fig. 11 in a further embodiment; andFig. 16 is a sectional view similar to the view of Fig. 13 in a further embodiment.DETAILED DESCRIPTION

[0016] Fig. 1 shows a section of the upper area of a single bed circular knitting machine 1, with a needle cylinder. The section is made according to an approximately radial plane, i.e., containing the axis A-A of the needle cylinder.

[0017] In the section of Fig. 1, number 2 indicates the needle cylinder and number 3 indicates one of the latch needles with which the needle cylinder 2 is equipped. In practice, as is known to those skilled in the art, needles 3 are arranged around the entire circular development of the needle cylinder 1 in a number corresponding to the fineness of the machine.

[0018] Each needle 3 slides in a respective longitudinal sliding groove 4 substantially parallel to the axis A-A of the needle cylinder 2. In some embodiments, each needle sliding groove 3 can be formed by milling the cylindrical surface of the needle cylinder 2. In the illustrated embodiment, each sliding groove is defined by two adjacent and consecutive slats, indicated with 5, extending parallel to the axis A-A of the needle cylinder 2 and fixed in corresponding millings formed in the needle cylinder 2. Some or all the slats 5 may be fitted with feet 5 A, for the purposes described below.

[0019] The needles 3 can be equipped with butts which cooperate with control cams, arranged in a cam skirt not shown, placed around the needle cylinder 2, as known tothose skilled in the art. The needles 3 can be retained in the sliding grooves by means of annular springs 7.

[0020] As visible in particular in Fig. 3, where the needle cylinder 2 is shown in a section similar to that of Fig. 1 , but without the needles and other components mounted thereon, the needle cylinder 2 has an upper end or edge 2A. Upper end is intended as the end at which the hooks of the needles 3 are arranged and from which they emerge during the knitting process.

[0021] Along the upper end or head end 2A of the needle cylinder 2, substantially radial grooves are formed, indicated with number 11. The radial grooves 11 extend radially from an outer lateral surface 2B to an inner lateral surface 2C of the needle cylinder 2. Advantageously, a radial groove 11 can be provided at each slat 5 delimiting a corresponding groove 4 for the sliding of the needles 3. In essence, therefore, for each needle 3 of the cylindrical needle bed defined by the needle cylinder 2, two radial grooves 11 are provided, positioned next to the sliding groove 4 of the needle 3 itself.

[0022] An insert 13 can be inserted inside each radial groove 11, shown separate from the needle cylinder 2 in the upper part of Fig. 3, and mounted in the radial groove 11 in Figs. 1 and 2. Fig. 3 A shows an enlargement in axonometric view of an isolated insert 13. The shape of the insert 13 will be described in more detail below.

[0023] The insert can be formed by a metal sheet that is punched or cut, for example by laser or other method.

[0024] In the embodiment illustrated in Figs. 1 to 3, the inserts 13 cooperate with respective movable elements 51 housed in horizontal radial sliding grooves 53 formed in an annular ring 55. The annular ring 55 is mounted coaxially to the needle cylinder 2 and fixed to the latter, for example, by means of the feet 5A of the slats 5 which delimit the sliding grooves of the needles 3. The movable elements 51 are controlled to move in reciprocating motion according to the double arrow f51 (Figs. 1 and 2) by cams (not shown) cooperating with a throat 51 A with which the movable elements 51 are equipped.

[0025] Each movable element 51 also has a finger 5 IB oriented radially inwards and superimposed on a respective insert 13.

[0026] The formation of the stitch with a circular knitting machine made as illustrated in Figs. 1 to 3 occurs in a manner known per se, as disclosed for example in EP2906743.

[0027] As mentioned, the use of interchangeable inserts 13 to form the stitch knock- over level allows for rapid repairs in the event of breakage or removal for replacement or for periodic maintenance and cleaning. To this end, it is important that the inserts are shaped so as to reliably and stably engage with the head of the needle cylinder 2, and to allow quick and easy attachment and removal operations.

[0028] In the embodiment of Figures 1 to 3 A, the insert 13 comprises a main body 13.1 with an upper edge 13.2 and a lower edge 13.3. In the mounted configuration, the upper edges of the individual inserts 13 lie on a toroidal surface which forms the stitch formation surface or level. The lower edge 13.3 of each insert 13 rests on the bottom of the respective radial groove 11. Preferably, each lower edge 13.3 (and consequently the bottom of the respective radial groove 11) is straight and orthogonal to the axis A- A of the needle cylinder 2. The main body 13.1 has, in an area that faces radially toward the outside when mounted, a portion of reduced thickness indicated by 13.4, which can be inserted under the fingers 5 IB of the movable elements 51.

[0029] Each insert 13 comprises a first appendage 13.5 extending from a first end of the main body 13.3, which when mounted is oriented radially towards the outside of the needle cylinder 2. Each insert 13 further comprises a second appendage 13.6 extending from a second end of the main body 13.3, which when mounted is oriented radially towards the inside of the needle cylinder 2.

[0030] The first appendage 13.5 and the second appendage 13.6 are approximately orthogonal to the lower edge 13.3 of the main body.

[0031] In the illustrated embodiment, see in particular Fig. 3 A, the second appendage 13.6 comprises a distal end 13.7 which forms two fingers 13.8 and 13.9, between which a recess 13.10 is defined and which is open toward the axis of the needle cylinder 2 when the insert 13 is mounted, see Figs. 1, 2. An end expansion of the second appendage 13.6 is defined with the number 13.11. The end expansion 13.11 protrudes towards the first appendage 13.5, and faces radially toward the outside, i.e., opposite with respect to the axis A-A of the needle cylinder 2, when the insert 13 is mounted.

[0032] When mounted, the expansion 13.11 formed at the distal end of the second appendage 13.6 engages with undercut in an annular channel 61 formed on the inner lateral surface 2C of the needle cylinder 2, in proximity to the head end 2A.

[0033] In some embodiments, the second appendage 13.6 has a side oriented toward the first appendage 13.5. The side extends from the lower edge 13.3 of the main body 13.1. More in particular, starting from the lower edge 13.3 of the main body 13.1, the side comprises a first portion 13.12, orthogonal to the lower edge 13.3 of the main body 13.1, and a second portion 13.13, diverging toward the axis A-A of the needle cylinder 2; wherein, when mounted, the first portion of the side of the second appendage is in contact with a cylindrical end portion of the inner lateral surface of the needle cylinder.

[0034] This tapered shape of the second appendage 13.6, in combination with a possible recess 13.14 in the connection area between the lower edge 13.3 and the second appendage 13.6, increases the bending deformability of the second appendage 13.6 and facilitates mounting the insert 13 in the respective radial groove 11, as well as its removal. Figs. 1 and 2 show in dashed lines the second appendage 13.6 in the undeformed configuration for inserting or removing the expansion 13.11 into or from the annular channel 61. In practice, to introduce the insert 13 into its seat formed by the respective radial groove 11, the second appendage 13.6 is deformed radially towards the axis A-A of the needle cylinder 2, as shown in a solid line, until the expansion 13.11 snaps inside the annular channel 61, while the first appendage 13.5 is engaged with the outer lateral surface 2B of the needle cylinder 2 in the manner described below.

[0035] More in particular, the first appendage 13.5 forms a hook 13.15 for engagement with a respective radial projection 63, protruding radially outward from the outer lateral surface 2B of the needle cylinder 2 and adjacent to a bottom surface of the respective radial groove 11.

[0036] In a different embodiment (see Fig. 1 A, where equal numbers indicate parts equal to those described in Figs. 1, 2 and 3) instead of a protruding projection, an annular groove 64 is provided at the cylindrical support surface of the needles 2B.

[0037] More in particular, each hook 13.15 comprises a side 13.16 which, whenmounted, faces the axis A-A of the needle cylinder 2 and is parallel therewith and rests on a radially outer surface of the respective radial projection 63. Each hook further comprises an end edge 13.17 which, when mounted, is orthogonal to the axis A-A of the needle cylinder 2 and engages with undercut and pressure on a lower surface of the respective radial proj ection 63. A hollow or recess 13.18 may be provided between the side 13.16 and the end edge 13.17. The hollow or recess extends from the side 13.16 in a radial outward direction, and is delimited by a concave edge formed in the metal sheet forming the insert 3. The concave edge forms a portion 13.22 of the first appendage 13.5, which has a reduced thickness, i.e., a reduced width, at which point the appendage has a greater elastic bending deformability. The increased bending deformability of the hook 13.15 formed by the first appendage 13.5 facilitates mounting the insert 13 on the needle cylinder 2.

[0038] In practice, the side 13.16 of each hook 13.15 is parallel to the first portion 13.12 of the side of the second appendage 13.6. When mounted, the side 13.16 of each hook 13.15 and the first portion 13.12 of the side of the second appendage 13.6 facing the first appendage 13.5 are in pressure contact against the radial projection 63 and against the cylindrical end portion of the inner lateral surface of the needle cylinder, which cylindrical end portion is located between the annular channel 61 and the bottom of the radial grooves 11.

[0039] The recess 13.10 formed between the fingers 13.8, 13.9 at the distal end of the second appendage 13.6 of each insert 13 forms a gripping element for a tool U for removing the insert 13 from the seat formed by the respective radial groove 11. Fig. 4 illustrates the use of the tool U which, in this embodiment, has a working end that inserts into the recess 13.10 to lift the insert 13 from inside the needle cylinder 2, to release it from its working position. By pulling the second appendage 13.6 upwards in an approximately axial direction using the tool U, the bending deformation thereof is caused, which frees the expansion 13.11 from the annular channel 61 in which the expansion is engaged with undercut.

[0040] The inclination of the second appendage 13.6 towards the axis A-A of the needle cylinder 2 facilitates the operation described above, since a pull exerted by the tool U in an approximately axial direction towards the outside of the cylinder causes the bending of the second appendage 13.6 and therefore the release of the insert 13.

[0041] The operation is further facilitated by the recess 13.18, which makes the appendage 13.5 and therefore the hook 13.15 more flexible. The assembly and disassembly of the insert is achieved by means of bending deformation of the first appendage 13.5 mainly in the narrowed area 13.22, and of the second appendage 13.6. Therefore, since the bending deformation is distributed between the two appendages, each appendage undergoes less deformation than if only one of them were deformable. This method helps prevent the insert from yielding.

[0042] Figs. 5 and 6 illustrate a modified embodiment of an insert 13. Equal numbers indicate equal or equivalent parts. In the embodiment of Fig. 5, the side of the second appendage 13.6 facing the first appendage 13.5 is divided into two portions 13.12 and 13.13 with the interposition of a step 13.20, so that the second appendage 13.6 has a smaller width in the distal part, which facilitates bending deformability and thus simplifies the assembly and disassembly of the insert.

[0043] Fig. 7 illustrates a different embodiment of an insert 13. In this case, the insert 13 comprises a main body 13.1 with an upper edge 13.2, defining a portion of the stitch forming surface, and a lower, preferably straight, edge 13.3. A first appendage 13.5 protrudes from the lower edge 13.3, extending from a first end of the main body 13.3, which when mounted is oriented radially towards the outside of the needle cylinder 2. Each insert 13 further comprises a second appendage 13.6 extending from a second end of the main body 13.3, which when mounted is oriented radially towards the inside of the needle cylinder 2. The first appendage 13.5 and the second appendage 13.6 are approximately orthogonal to the lower edge 13.3 of the main body.

[0044] In the embodiment of Fig. 7, the second appendage 13.6 comprises a distal end 13.7 that forms a terminal expansion of the second appendage 13.6. The terminal expansion 13.11 protrudes towards the first appendage 13.5, and is faces radially toward the outside, i.e., opposite with respect to the axis A-A of the needle cylinder 2, when the insert 13 is mounted. When mounted, the expansion 13.11 formed at the distal end of the second appendage 13.6 engages with undercut in an annular channel 61 formed on the inner lateral surface 2C of the needle cylinder 2, in proximity to the head end 2 A. In practice, the expansion 13.11 has the same function as the expansion 13.11 of the embodiments described with reference to Figs. 1 to 6. However, the second appendage 13.6 does not have an element for engagement with the tool U fordisassembling the insert 13 from the respective groove 11.

[0045] Even in the embodiment shown in Fig. 7, the second appendage 13.6 has a side oriented toward the first appendage 13.5. The side extends from the lower edge 13.3 of the main body 13.1. More in particular, the side comprises, starting from the lower edge 13.3 of the main body 13.1, a first portion 13.12, orthogonal to the lower edge 13.3 of the main body 13.1, and a second portion 13.13, diverging toward the axis A-A of the needle cylinder 2; wherein, when mounted, the first portion of the side of the second appendage is in contact with a cylindrical end portion of the inner lateral surface of the needle cylinder.

[0046] This tapered shape of the second appendage 13.6, in combination with a possible recess 13.14 in the connection area between the lower edge 13.3 and the second appendage 13.6, increases the bending deformability of the second appendage 13.6 and facilitates mounting the insert 13 in the respective radial groove 11, as well as its removal. The assembly of the insert 13 in its seat formed by the respective radial groove 11 occurs as already described with reference to the previous figures.

[0047] Alternatively, the second appendage 13.6 of the insert of Fig. 7 can be shaped with a step 13.20 along the inner side, i.e., the side facing the first appendage 13.15.

[0048] The first appendage 13.5 of the insert 13 of Fig. 7 is configured as already described with reference to the previous figures.

[0049] Fig. 8 illustrates a side view of a modified embodiment of an insert according to the present disclosure. Identical reference numbers indicate the same elements and parts previously described with reference to the previous figures. The embodiment of Fig. 8 differs from the embodiments of Figs. 1 to 6 mainly in that the recess 13.14 extends deeper into the main body 13.1 of the inserts 13 and forms a portion 13.24 of the second appendage 13.6 which is thinner, i.e., has a smaller width with respect to the portion of the same appendage 13.6 where the first portion 13.12 of the side of said first appendage is oriented toward the first appendage 13.5. The thinner part 13.24 of the second appendage 13.6 gives a greater elastic bending deformability to the second appendage 13.6, facilitating the assembly of the inserts on the needle cylinder.

[0050] Fig. 9 shows a section, similar to Fig. 1, without the indication of the needles3, and with the needle cylinder 2 set up with a plurality of inserts 13 of the type illustrated in Fig. 6. The upper edges 13.2 of the inserts 13 are coplanar and the plane on which they lie represents a knock-over level, i.e. a stitch-forming surface. Figs. 11 and 12 show the movements of the needles 3 and the elements 51 in the process of forming the stitch. The movable elements 51 each have a front nose 51.1 and a butt 51.2, which cooperate with cams (not shown) adapted to control the radial movement according to f51 of the movable elements 51. In some embodiments, the movement can be controlled with cams that cooperate with the throat 51 A of the movable element 51, rather than with a butt.

[0051] During stitch formation, the noses 51.1 cooperate with the inserts 13 and the needles 3 to form the stitches of the fabric. Each insert 13 is substantially coplanar with the movable element 51 in a plane containing the axis of the needle cylinder 2.

[0052] To reduce friction during the stitch formation movements, it is envisaged that there is no contact between the upper edge 13.2 of each insert 13 and the respective coplanar element 51, and more precisely the lower edge 51.3 of the latter, facing the corresponding insert 13. The small distance that is maintained between the upper edges 13.2 of the inserts 13, which form the stitch knock-over level, and the edges 51.3 of the movable elements 51, does not normally create problems for stitch formation.

[0053] There are, however, situations in which this distance, albeit minimal, can create difficulties in forming stitches or defects in the finished product.

[0054] If a fabric must be produced, for which the use of the inserts 13 and the movable elements 51 may represent a critical issue during knitting, it is possible to provide the knitting machine, of which the needle cylinder 2 is a part, with a set of sinkers, adapted to replace the movable elements 51 and the inserts 13. As described below, these sinkers are adapted to be guided in the radial grooves 11 formed in the needle cylinder head 2 and in the radial horizontal sliding grooves 53 formed in the annular ring 55.

[0055] Fig. 10 shows the machine equipped with sinkers 101 each inserted in a respective radial horizontal sliding groove 53 formed in the annular ring 55 and in the corresponding radial groove 11 formed on the head end of the needle cylinder 2. Each sinker 101 replaces the movable element 51 and the respective insert 13. In fact, boththe inserts 13 and the movable elements 51 have been removed to make room for the sinkers 101.

[0056] Each sinker 101 has a beak 101.1, an upper edge 101.2, which forms part of the stitch knock-over level, and a butt 101.3 adjacent to a throat 101.4. In practice, each sinker 101 has a radially inner portion 101A (Fig. 10) which is guided in the respective radial groove 11 formed in the head of the needle cylinder 2 and replaces the respective insert 13. Each sinker 101 also has a radially outer portion 101B, guided in the radial sliding groove 53 and takes the place of the movable element 51.

[0057] Instead of using the butt 101.3, the control of the radial movement of the sinker may be imparted by a cam cooperating with the throat 101.4, in a manner like that envisaged for the radial movement of the movable elements 51, provided with a throat 51 A cooperating with a control cam, not shown. The same cam or series of cams can be used to alternatively control the radial movement of the sinkers 101 or the radial movement of the movable elements 51, depending on how the knitting machine is set up.

[0058] The radially inner portion 101 A has a straight lower edge 101.5, sliding along the radial groove 11, in contact with the bottom thereof. Similarly, the radially outer portion 10 IB of each sinker 101 has a straight lower edge 101.5, sliding along the radial sliding groove 53 of the annular ring 55, and in contact with the bottom of this groove.

[0059] In the illustrated embodiment, the portions 101A, 101B of each sinker are configured with the lower edges 101.5 and 101.6 offset from each other in the axial direction. In the illustrated embodiment, the edge 101.5 is in a position lower than the edge 101.6 when the sinkers are mounted on the machine. In other words, the lower edge 101.5 is located at distance from the head surface of the needle cylinder 2 greater than the distance of the lower edge 101.6. This corresponds to the mutual position of the bottom of the grooves 11, 53, and allows the replacement of the movable elements 51 and the inserts 13 with the sinkers 101, or vice versa, without any other structural intervention to adapt the machine, and particularly the needle cylinder 2. The replacement can therefore occur extremely quickly and easily. A reverse configuration cannot be ruled out, with the lower edge 101.6 at a lower height than the edge 101.5.

[0060] The sinkers 101 therefore have a shape that is a function of the shape of the inserts 13 and the movable elements 51, in order to be able to take their place in the knitting machine, without having to modify the annular ring 55 and / or the needle cylinder 2.

[0061] The sinkers 101 work in the knitting cycle in a manner corresponding to what occurs in traditional machines and their radial movement (arrow f 101) is controlled by cams which act on the butts 101.3, similarly to the movement of the movable elements 51, always controlled by the cams cooperating with the butts 51.3 of these movable elements.

[0062] Figs. 13 and 14 show the relative movements of the needles 3 and the sinkers 101 to form the knitted fabric. These reciprocating movements are represented by the double arrows f3 and flOl. Similarly, in Figs. 11 and 12, f3 and f51 indicate the reciprocating movements of the needles 3 and the movable elements 51, when the machine is set up with the fixed inserts 13 and the movable elements 51.

[0063] By setting up the knitting machine with the sinkers 101 replacing the movable elements 51 and the inserts 13, the knock-over level is formed by the set of the upper edges 101.2, coplanar with each other, of the sinkers 101, instead of the knock-over level formed by the upper edges 13.2 of the stationary inserts 13.

[0064] In practice, it is possible to supply the producer of knitted goods with a kit comprising a circular knitting machine comprising the needle cylinder 2, and the needles 3. The kit further comprises a set of inserts 13 which can be inserted into the radial grooves 11 and fixed therein in the manner previously described, and a set of movable elements 51 which can be inserted into the radial grooves 53. The kit further comprises a set of sinkers 101, which can be inserted into the radial grooves 11 of the needle cylinder 2 and into the radial grooves 53 of the annular ring 55, to replace the inserts 13 and the movable elements 51.

[0065] The inserts 13 can have any suitable shape, including those described with reference to the previous figures. It is not excluded that the inserts have other shapes known from the state of the art, in particular those illustrated in the prior art documents mentioned in the introductory part of this description.

[0066] With this kit, it is possible to set up the knitting machine as shown in Figs. 9, 11 and 12, with the inserts 13 anchored to the head of the needle cylinder 2, and housed in the radial grooves 11, in combination with the movable elements 51 inserted in the radial sliding grooves 53 of the annular ring 55.

[0067] When the user of the machine requires the production of a fabric that may not be optimally achieved with this setup, the user will proceed by simply removing the inserts 13 and the movable elements 51 and replacing them with the sinkers 101. The machine will thus be set up as shown in Figs. 10, 13 and 14, and will be able to function as a machine with traditional type sinkers.

[0068] The reverse setup is performed when it is desired to return to knitting with the stationary inserts 13 and the movable elements 51, by removing the sinkers 101 and inserting the stationary inserts 13 and the movable elements 51. The machine thus set up (Figs. 9, 11, 12) will operate without sinkers and with the stationary inserts 13 and the movable elements 51.

[0069] The transition from one setup to another can occur without any modification to the needle cylinder.

[0070] Figures 15 and 16 show, in a section along a plane containing the axis of the needle cylinder, a further embodiment of the circular knitting machine, limited to an upper portion of the needle cylinder. In Fig. 15 the knitting machine is set up with the movable elements 51 and the inserts 13, while in Fig. 16 the knitting machine is set up with the sinkers 101. The movable elements 51, the sinkers 101 and the inserts 13 can be made as described with reference to the previous figures. The same reference numbers indicate, in Figs. 15 and 16, the same parts described above and which will not be described again here.

[0071] The main difference between the embodiment of Figures 1 to 14 and the embodiment of Figures 15 and 16 relates to the configuration of the needle cylinder 2.

[0072] In the previous figures, the needle cylinder 2 is monolithic. Conversely, in the embodiment of Figures 15 and 16 the needle cylinder 2 comprises a main body 2.1 (hereinafter referred to as “body 2.1 of the needle cylinder 2”) and a removable annular element 2.2. The removable annular element 2.2 forms the upper end, i.e., the headend of the needle cylinder 2 and therefore in particular its upper edge 2A. The removable annular element 2.2 can be mechanically coupled with high precision to the body2.1 of the needle cylinder 2. The radial grooves 11 are formed on an upper surface of the removable annular element 2.2.

[0073] In contrast, in the illustrated embodiment, the needle sliding grooves 4 are formed entirely in the body 2.1 of the needle cylinder 2. In Figs. 15 and 16, the needles 3 are omitted for simplicity of representation, but may be the same as those described with reference to Figs. 1 to 14 and retained in the same way inside the respective grooves 4. The slats 5 can also be configured and mounted as described in relation to the embodiments of the previous figures.

[0074] To removably and precisely fix the removable annular element 2.2 to the body2.1 of the needle cylinder 2, complementary coupling surfaces are provided on the two components 2.1 and 2.2 forming the needle cylinder 2, which can form mutual centring means, so that the removable annular element 2.2 can be mounted in a perfectly coaxial manner to the body 2.1 of the needle cylinder.

[0075] In some embodiments, the body 2.1 of the needle cylinder 2 has, at its upper end, an annular end projection or relief 2.3. In some embodiments, a first centring surface is formed on the inner side of the annular end projection 2.3 between the body2.1 of the needle cylinder 2 and the removable annular element 2.2. This first centring surface, facing the axis of the needle cylinder, is concave and can in turn have a first concave conical surface 2.4 and a second concave cylindrical surface 2.5, which is arranged between the end of the annular end projection 2.3 and a base 2.6 from which the annular end projection 2.3 extends. The removable annular element 2.2 comprises an outer convex surface complementary to that of the annular end projection 2.3. More in particular, the removable annular element 2.2 has a conical convex surface 2.8 complementary to the conical concave surface 2.4 and a cylindrical convex surface 2.9 complementary to the cylindrical concave surface 2.5 of the annular end projection 2.3. In practice, the cylindrical surfaces are an extension of the conical surfaces and therefore their diameter is preferably equal to the minimum diameter of the corresponding conical surfaces.

[0076] When mounted, the removable annular element 2.2 and the body 2.1 of theneedle cylinder 2 can be in mutual contact along the two complementary surfaces. For example, contact can occur along the complementary conical surfaces 2.8 and 2.4, thus ensuring mutual centring. Alternatively, or in combination, the mutual contact can occur along the cylindrical surfaces 2.5, 2.9.

[0077] In the illustrated embodiment, the removable annular element 2.2 does not rest on the flat front annular surface of the annular end projection 2.3. In other embodiments, not shown, the annular element 2.2 may, instead, rest vertically on the flat annular front surface of the annular end projection 2.3.

[0078] In some embodiments, for example, screw members 51 are provided to fix the removable annular element 2.2 to the body 2.1 of the needle cylinder 2. The screw members, or other removable members, can be distributed according to a circular ring, preferably inside the removable annular element 2.2, so as not to interfere with other members, in particular the needles 3, of the needle cylinder 2. In the illustrated embodiment, the screw members 51 are housed with a head in respective cavities formed radially inside the removable annular element 2.2 and are screwed into radial threaded holes, with the inlet opening facing the axis A-A of the needle cylinder 2, preferably formed along the cylindrical surface 2.5 of the annular end projection 2.3.

[0079] In other embodiments, the removable annular element 2.2 may be stably connected to the body 2.1 of the needle cylinder 2 in another manner, for example by gluing, by interference, by hot interference, or other methods that allow the removal thereof without damaging the body 2.1 of the needle cylinder 2.

[0080] The removable annular element 2.2 is preferably made in a single monolithic piece, for reasons of manufacturing precision, but the possibility of making it in sectors, each of which covers an angle of less than 360°, is not excluded.

[0081] The radial seats or grooves 11 may be subject to damage during use. By making these radial grooves 11 in the removable annular element 2.2, in the event of damage, wear or breakage of one or more radial grooves 11, it is possible to repair the knitting machine in limited time and at limited cost by simply replacing the removable annular element 2.2. If the removable annular element is made of multiple sectors, only the sector or sectors affected by the damage can be removed.

[0082] The replacement of the removable annular element or a sector thereof can be performed quickly and with limited costs, compared with the repair (or replacement) of the entire needle cylinder 2. It is also possible to repair the removable annular element that has been removed by easily transporting it to a specialised workshop or la- boratory, without having to disassemble the entire machine and move the entire needle cylinder.

[0083] The creation of the needle cylinder 2 in two components 2.1, 2.2 for the purposes and with the advantages indicated above can also be adopted for knitting machines other than the one described here, in general when the front, i.e., upper, surface of the needle cylinder may be subject to wear or breakage with consequent prejudice to the correct operation of the machine.

Claims

CLAIMS1. A kit comprising: a single-bed circular knitting machine with a needle cylinder, wherein the needle cylinder comprises an outer lateral surface, an inner lateral surface and a head end; wherein on the outer lateral surface are arranged sliding grooves for a plurality of needles, parallel to an axis of the needle cylinder; wherein on the head end of the needle cylinder, a respective radial groove is provided between each pair of adjacent sliding grooves; a series of inserts, each insertable into one of said radial grooves on the head end of the needle cylinder; wherein each insert comprises a main body with an upper edge and a lower edge, the upper edges of the inserts protruding from the respective radial grooves when the inserts are applied to the needle cylinder and defining a stitch forming surface; and the lower edges resting on the bottom of the respective radial grooves; wherein each insert comprises members for engaging with the needle cylinder; a series of movable elements, each insertable into a radial sliding groove formed in an annular ring integral with the needle cylinder and external thereto, each movable element being adapted to slide radially in the radial sliding grooves and to cooperate with a respective insert and with the needles to form stitches; a series of sinkers, shaped to each be inserted partially into a respective one of said radial grooves on the head end of the needle cylinder and partially into a respective one of said sliding grooves of the annular ring, to replace the inserts and movable elements.

2. The kit of claim 1, wherein the members for engaging the inserts with the needle cylinder comprise elastically deformable members.

3. The kit of claim 1 or 2, wherein each insert has a first radially external appendage, extending from a first end of the main body and adapted to engage with the outer lateral surface of the needle cylinder, and a second radially internal appendage, extending from a second end of the main body and adapted to engage with the inner lateral surface of the needle cylinder.

4. The kit of claim 3, wherein the distal end of the second appendage of each insert comprises a pair of teeth forming a recess for inserting a removal tool.

5. The kit of claim 3 or 4, wherein the distal end of the second appendage of each insert comprises a protrusion which, when mounted, is oriented radially towards the outside of the needle cylinder and engages with undercut in an annular channel formed on the inner lateral surface of the needle cylinder.

6. The kit of any one of claims 3 to 5, wherein the second appendage has a tapered shape from a proximal end, adjacent to the insert body, to the distal end, the tapered shape increasing the bending deformability of the second appendage.

7. The kit of any one of claims 3 to 6, wherein the second appendage of each insert comprises a side oriented toward the first appendage and which extends from the lower edge of the main body; wherein the side comprises, starting from the lower edge of the main body, a first portion orthogonal to the lower edge of the main body, and a second portion diverging toward the axis of the needle cylinder; wherein, when mounted, the first portion of the side of the second appendage is in contact with a cylindrical end portion of the inner lateral surface of the needle cylinder.

8. The kit of any one of claims 3 to 7, wherein the first appendage of each insert forms a hook for engaging with a respective annular groove of the outer lateral surface of the needle cylinder, or in a respective radial projection protruding radially outward from the outer lateral surface of the needle cylinder and adjacent to a bottom surface of the respective radial groove.

9. The kit of claim 8, wherein each hook comprises a side which, when mounted, faces the axis of the needle cylinder and rests on a radially outer surface of the needle cylinder; wherein the hook comprises an end edge which, when mounted, engages with undercut and with pressure in the annular groove or with a lower surface of the respective radial projection.

10. The kit of claim 9, wherein the side is parallel to the axis of the needle cylinder and the end edge is orthogonal to the axis of the needle cylinder.

11. The kit of claim 9 or 10, wherein each hook comprises a recess between the side and the end edge of the hook, the recess extending radially outwardbeyond the side, thereby forming a section of increased elastic deformability of said first radially outer appendage.

12. The kit of any one of claims 8 to 11, when dependent at least on claim 7, wherein the side of each hook is parallel to the first portion of the side of the second appendage facing the first appendage; wherein, when mounted, the side of each hook is in contact with pressure against the outer lateral surface of the needle cylinder or against the radial projection; and wherein the first portion of the side of the second appendage is in contact with pressure against the cylindrical end portion of the inner lateral surface of the needle cylinder.

13. The kit of any one of the preceding claims, wherein each sinker has: a first radial portion with an upper edge which, when mounted, is located on a stitch knock-over level, wherein, when mounted, the first radial portion is engaged with one of said radial grooves of the head end of the needle cylinder; and a second radial portion with at least one butt or one throat, adapted to cooperate with control cams of the sinkers, wherein, when mounted, the second radial portion is engaged in one of said radial sliding grooves of the annular ring.

14. The kit of claim 13, wherein the first radial portion has a lower edge which, when mounted, slidably engages with the bottom of the corresponding radial groove in the head end of the needle cylinder, and wherein the second radial portion has a lower edge which, when mounted, slidably engages with the bottom of the corresponding radial sliding groove formed in the annular ring.

15. The kit of claim 14, wherein the lower edges of the first radial portion and the second radial portion of each sinker are straight.

16. The kit of claim 15, wherein the lower edge of the first radial portion and the lower edge of the second radial portion are offset from each other in the direction orthogonal to a longitudinal development of the sinker.

17. The kit of claim 16, wherein, when mounted, the lower edge of the first radial portion is on a plane orthogonal to the axis of the needle cylinder, arranged at a distance from a head surface of the needle cylinder, greater or less than the distancebetween the head surface of the needle cylinder and a plane orthogonal to the axis of the needle cylinder, on which the lower edge of the second radial portion is located.

18. The kit of any one of the preceding claims, wherein the needle cylinder comprises a needle cylinder body and a removable annular element, forming the head end of the needle cylinder and on which the radial grooves are formed.

19. The kit of claim 18, wherein the annular element is anchorable to the needle cylinder body by means of a plurality of removable fixing members, in particular a plurality of screw members.

20. The kit of claim 18 or 19, wherein the needle cylinder body and the removable annular element comprise respective mutual coupling surfaces, configured to ensure a mutual coaxial coupling.

21. The kit of claim 18 or 19 or 20, wherein the needle cylinder body comprises an annular end projection with a concave conical surface facing the axis of the needle cylinder, and wherein the removable annular element comprises a convex conical surface, complementary to the concave conical surface of the needle cylinder body; wherein, when mounted, the convex conical surface faces the outside of the needle cylinder; and wherein the concave conical surface and the convex conical surface are preferably in mutual contact and coaxial with the axis of the needle cylinder.

22. The kit of any one of claims 18 to 21 , wherein the removable annular element comprises a convex cylindrical surface, of a diameter preferably equal to a minimum diameter of the convex conical surface and constituting an extension of the convex conical surface; wherein the annular end projection of the body of the needle cylinder comprises a concave cylindrical surface, complementary to the convex cylindrical surface of the removable annular element; and wherein, when mounted, the concave cylindrical surface and the convex cylindrical surface are preferably in mutual contact.

23. The kit of claim 22, wherein the removable annular element is fixable to the needle cylinder body by means of fixing members arranged annularly around the axis of the needle cylinder at the concave cylindrical surface and the convex cylindrical surface.

24. The kit of any one of claims 18 to 23, wherein the needle sliding grooves are integrally formed in the needle cylinder body.

25. A method for setting up a single bed circular knitting machine of a kit according to one or more of the preceding claims, wherein the method comprises: introducing a respective insert into each radial groove of the head end of the needle cylinder and anchoring said insert to the needle cylinder; and introducing a movable element into each radial sliding groove of the annular ring, adapted to cooperate with a respective insert radially aligned therewith; or introducing a respective sinker partially into one of said radial grooves on the head end of the cylinder and partially into a corresponding sliding groove of the annular ring, as a function of the knitted fabric to be manufactured.

26. A cylinder for a single bed circular knitting machine comprising an outer lateral surface, an inner lateral surface and a head end; wherein on the outer lateral surface are provided sliding grooves for a plurality of needles, parallel to an axis of the needle cylinder; wherein on the head end of the needle cylinder, between each pair of adjacent sliding grooves, a respective radial groove is provided; wherein the needle cylinder comprises a needle cylinder body and a removable annular element, forming the head end of the needle cylinder and on which the radial grooves are formed.

27. The cylinder of claim 26, wherein the annular element is anchorable to the needle cylinder body by means of a plurality of removable fixing members, in particular a plurality of screw members.

28. The cylinder of claim 26 or 27, wherein the needle cylinder body and the removable annular element comprise respective mutual coupling surfaces, configured to ensure a mutual coaxial coupling.

29. The cylinder of claim 26 or 27 or 28, wherein the needle cylinder body comprises an annular end projection with a concave conical surface facing the axis of the needle cylinder, and wherein the removable annular element comprises a convex conical surface, complementary to the concave conical surface of the needle cylinder body; wherein, when mounted, the convex conical surface faces the outside of the needle cylinder; and wherein the concave conical surfaceand the convex conical surface are preferably in mutual contact and coaxial with the axis of the needle cylinder.

30. The cylinder of claim 29, wherein the removable annular element comprises a convex cylindrical surface, of a diameter preferably equal to a minimum diameter of the convex conical surface and constituting an extension of the convex conical surface; wherein the annular end projection of the body of the needle cylinder comprises a concave cylindrical surface, complementary to the convex cylindrical surface of the removable annular element; and wherein, when mounted, the concave cylindrical surface and the convex cylindrical surface are preferably in mutual contact.

31. The cylinder of claim 30, wherein the removable annular element is fixable to the needle cylinder body by means of fixing members arranged annularly around the axis of the needle cylinder at the concave cylindrical surface and the convex cylindrical surface.

32. The cylinder of any one of claims 26 to 31, wherein the needle sliding grooves are integrally formed in the needle cylinder body.

33. A single bed circular knitting machine comprising: a cylinder according to one or more of claims 26 to 32, a plurality of needles slidably housed in the sliding grooves; a plurality of inserts, each inserted into a respective radial groove; and a series of movable elements, each insertable in a radial sliding groove formed in an annular ring integral with the needle cylinder and external thereto, each movable element being adapted to slide radially in the radial sliding grooves and to cooperate with a respective insert and with the needles to form stitches.

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