Needle cylinder of a knitting machine with removable inserts, machine with the needle cylinder and inserts for the needle cylinder

Description

TECHNICAL FIELD

[0001] The present invention relates to single-cylinder knitting machines, and more in particular to single-cylinder knitting machines with latch needles.BACKGROUND TO THE INVENTION

[0002] Single-cylinder knitting machines are provided with a single circular needle bed comprising needles sliding in sliding grooves, also called guiding grooves, provided in a needle cylinder. For forming stitches, the needles cooperate with a ring of sinkers provided with a reciprocating radial movement synchronized with the downward and upward movement of the needles.

[0003] Sinkerless circular knitting machines have been also produced, as well as knitting machines provided with fixed sinkers, arranged for instance on the upper end of the needle cylinder.

[0004] In the machines without sinkers or in those with fixed sinkers, the stitches are formed on a knitting surface, also called stitch formation surface, comprising inserts attached to the upper end of the needle cylinder, i.e. to the end where there are the needle hooks that are cyclically extracted and retracted to take the yarn and to form the stitches.

[0005] Sinkerless knitting machines are disclosed in EP3268526, EP2906743 and in EP2108725.

[0006] In EP2906743, a single-cylinder knitting machine is disclosed, including one needle cylinder and a plurality of latch needles sliding in respective grooves of the needle cylinder. An annular channel with an undercut is advantageously provided along one end of the needle cylinder. Between adjacent sliding grooves, a substantially radial respective groove is provided, formed in the needle cylinder and intersecting the annular channel. An insert is housed in each groove. The various inserts form, with the respective upper edges, a stitch formation surface, i.e. a knitting surface. Each insert can have an appendix that is inserted and blocked in the undercut of the annular channel. A blocking element holds the inserts in working position in their respective grooves. In working position, the appendices of the inserts are advantageously pushed in the undercut of the annular channel by the blocking element, so as to keep the inserts fixed during the knitting process, preventing the inserts from exiting the grooves. By removing or deactivating the blocking element it is possible to remove and to replace one or more inserts, for instance when worn or damaged.

[0007] In EP3268526, a sinkerless single-cylinder knitting machine is disclosed, in which the inserts are formed by shaped foils, which engage, by elastic deformation, the upper end of the needle cylinder. For this purpose, each insert has an S-shaped elastic appendix that engages an inner annular surface of the needle cylinder. EP2108725 discloses a similar solution, with a differently shaped appendix. US2016 / 0348287 discloses a circular knitting machine comprising a plurality of laminar elements mounted on the top end of then needle cylinder and interspersed between needles. Each laminar element has a top edge forming part of a stitch-forming surface.

[0008] These systems having interchangeable inserts are particularly efficient, but not always effective in the needle assembly and disassembly phases.

[0009] There is therefore the need to improve the sinkerless single-cylinder knitting machines and the respective interchangeable inserts, in order to achieve better efficiency.SUMMARY

[0010] According to the invention, as defined by independent claim 1, a needle cylinder includes an outer side surface, an inner side surface and a leading end. Sliding grooves for the needles are provided on the outer side surface, parallel to an axis of the needle cylinder. On the leading end, a radial groove is provided between each pair of adjacent sliding grooves. An insert is housed in each radial groove, each insert including a main body with a top edge and a bottom edge, the top edges of the inserts projecting from the respective radial grooves and defining a stitch formation surface, and the bottom edges resting on the bottom of the respective radial grooves. Each insert has a first radially outer appendix, extending from a first end of the main body and engaging the outer side surface of the needle cylinder, and a second radially inner appendix, extending from a second end of the main body and engaging the inner side surface of the needle cylinder, wherein a distal end of the second appendix includes a protrusion that is oriented toward the first appendix. The second appendix of the insert comprises a recess forming a gripping element for a removal tool.

[0011] The gripping element for the removal tool facilitates removing an insert that shall be replaced, for example when broken or worn.

[0012] The invention also relates to a single-cylinder knitting machine, including a needle cylinder as described above.

[0013] According to independent claim 12, the invention also relates to an insert for a needle cylinder of a knitting machine, wherein the insert includes a main body with a top edge and a bottom edge, wherein the top edge is adapted to define a stitch formation surface when the insert is inserted in the knitting machine; and wherein each insert includes a first appendix, extending from a first end of the main body, and a second appendix, extending from a second end of the main body. Characteristically, the second appendix has a recess forming a gripping element for a removal tool and the distal end of the second appendix includes a protrusion that is oriented toward the first appendix.

[0014] Further characteristics and embodiments of the invention are described in the description below and in the attached claims.BRIEF DESCRIPTION OF THE DRAWING

[0015] The invention will be better understood by following the description below and the attached drawings, showing non-limiting embodiments of the invention. More specifically, in the drawing: Figs. 1 and 2 show two cross-sections, according to a radial plane, of a portion of the head of a needle cylinder of a single-cylinder knitting machine, in two distinct working positions; Fig. 1A shows a cross-section analogous to that of Figs. 1 and 2, in a modified embodiment; Fig. 3 shows a cross-section analogous to that of Figs. 1 and 2, with an insert disassembled from the respective groove; Fig. 3A is a magnified axonometric view of the insert shown in Fig. 3; Fig. 4 shows a cross-section analogous to that of Fig. 1, with an insert removal tool in the working position; Figs. 5 and 6 show a side view and an axonometric view of an insert in a different embodiment; Fig. 7 is an axonometric view of an insert in an example, which does not form part of the invention; and Fig.8 is a side view of a modified embodiment of the insert. DETAILED DESCRIPTION

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

[0017] In the cross-section shown in Fig. 2, reference number 2 indicates the needle cylinder and reference number 3 indicates one of the latch needles, with which the needle cylinder 2 is equipped. Practically, as it is well known to those skilled in the art, needles 3 are arranged around the whole circular extension 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 that is substantially parallel to the axis A-A of the needle cylinder 2. In some embodiments, each groove where the needles 3 slide can be formed through milling of the cylindrical surface of the needle cylinder 2. In the illustrated embodiment, each sliding groove is defined by two adjacent and consecutive bars 5, that extend parallel to the axis A-A of the needle cylinder 2 and are fixed in corresponding milled slots provided in the needle cylinder 2. Some or all the bars 5 are provided with feet 5A for the purposes described below.

[0019] The needles 3 can be provided with butts cooperating with control cams arranged in a cam box, not shown and arranged around the needle cylinder 2, according to what is well known to those skilled in the art. The needles 3 can be held in the sliding grooves by means of annular springs 7.

[0020] As shown in particular in Fig. 3, where the needle cylinder 2 is shown in a cross-section analogous to that of Fig. 1 but without the needles and other components mounted on it, the needle cylinder 2 has an upper end or edge 2A, here below referred to as leading end 2A. "Leading end" means the end at which the hooks of the needles 3 are arranged, and wherefrom the hooks of the needles exit during the knitting process.

[0021] Substantially radial grooves 11 are provided along the leading end 2A of the needle cylinder 2. The radial grooves 11 extend radially from an outer side surface 2B to an inner side surface 2C of the needle cylinder 2. Advantageously, a radial groove 11 is provided in correspondence of each bar 5 delimiting a corresponding sliding groove 4 where the needles 3 slide. Therefore, for each needle 3 of the cylindrical needle bed defined by the needle cylinder 2, two radial grooves 11 are essentially provided, arranged at the side of the sliding groove 4 where the needle 3 slides.

[0022] An insert 13 is inserted inside each radial groove 11, the insert being 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. 3A shows an axonometric magnified view of an insert 13 in isolation. The shape of the insert 13 will be described below in more detail.

[0023] The insert is formed by a metal sheet, that is trimmed or cut, for instance by laser or with another method.

[0024] In the embodiment shown in Figs. 1 to 3, the inserts 13 cooperate with respective movable elements 51 housed in horizontal sliding grooves 53 provided in an annular crown 55. The annular crown 55 is mounted coaxially with the needle cylinder 2 and is fixed thereto for instance through the feet 5A of the bars 5 delimiting the sliding grooves of the needles 3. The movable elements 51 are controlled so as to move with reciprocating motion according to the double arrow f51 (Figs. 1 and 2) by cams (not shown) cooperating with a respective indentation 51A, with which the movable elements 51 are provided.

[0025] Furthermore, each movable element 51 has a finger 51B oriented radially inwards and superposed onto a respective insert 13.

[0026] Using a circular knitting machine configured as shown in Figs. 1 to 3, the stitches are formed in a known manner, as disclosed for example in EP2906743.

[0027] As mentioned, the use of interchangeable inserts 13 for forming the knitting surface allows rapid repair interventions in case of breakage or removal for replacement or for periodic maintenance and cleaning. To this end, it is important that the inserts are so shaped as to engage reliably and stably the head of the needle cylinder 2, and to allow for quick and easy coupling and removal operations.

[0028] In the embodiment of Figs. 1 to 3A, the insert 13 includes a main body 13.1 with a top edge 13.2 and a bottom edge 13.3. When mounted, the top edges of the individual inserts 13 lie on a toroidal surface that forms the stitch formation surface. The bottom edge 13.3 of each insert 13 rests on the bottom of the respective radial groove 11. Preferably, each bottom edge 13.3 (and consequently the bottom of the respective radial groove 11) is rectilinear and orthogonal to the axis A-A of the needle cylinder 2. The main body 13.1 has, in an area that, when mounted, faces radially outward, a portion 13.4 of reduced thickness, which can be inserted below the fingers 51B of the movable elements 51.

[0029] Each insert 13 includes a first appendix 13.5 that extends from a first end of the main body 13.1 and, when mounted, is oriented radially toward the outside of the needle cylinder 2. Each insert 13 also includes a second appendix 13.6 that extends from a second end of the main body 13.1 and, when mounted, is oriented radially toward the inside of the needle cylinder 2.

[0030] The first appendix 13.5 and the second appendix 13.6 are approximately orthogonal to the bottom edge 13.3 of the main body 13.1.

[0031] In the illustrated embodiment, see especially Fig. 3A, the second appendix 13.6 includes a distal end 13.7 that forms two fingers 13.8 and 13.9, between which a recess 13.10 is defined that is open toward the axis of the needle cylinder 2 when the insert 13 is mounted, see Figs. 1, 2. The reference number 13.11 indicates a terminal expansion or protrusion of the second appendix 13.6. The terminal expansion or protrusion 13.11 protrudes toward the first appendix 13.5 and faces radially outward, i.e. toward the opposite side with respect to the axis A-A axis of the needle cylinder 2, when the insert 13 is mounted.

[0032] When mounted, the terminal expansion 13.11 formed at the distal end of the second appendix 13.6 engages, in undercut fashion, an annular channel 61 formed on the inner side surface 2C of the needle cylinder 2, near the leading end 2A.

[0033] In some embodiments, the second appendix 13.6 has a flank that is oriented toward the first appendix 13.5. The flank extends from the bottom edge 13.3 of the main body 13.1. In more detail, the flank comprises, starting from the bottom edge 13.3 of the main body 13.1, a first portion 13.12 orthogonal to the bottom 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; when mounted, the first portion 13.12 of the flank of the second appendix 13.6 contacts a cylindrical end portion of the inner side surface of the needle cylinder 2.

[0034] This tapered shape of the second appendix 13.6, combined, if necessary, with a recess 13.14 provided in the junction area between the bottom edge 13.3 and the second appendix 13.6, increases the flexural deformability of the second appendix 13.6 and facilitates the mounting of the insert 13 in, and the removal of the insert 13 from, the respective radial groove 11. In Figs. 1 and 2, a broken line indicates the second appendix 13.6 in undeformed arrangement for inserting the expansion 13.11 in, or removing it from, the annular channel 61. In practice, in order to introduce the insert 13 in the corresponding seat formed by the respective radial groove 11, the second appendix 13.6 is radially deformed toward the axis A-A of the needle cylinder 2, as indicated by a solid line, until the expansion 13.11 snaps inside the annular channel 61, whilst the first appendix 13.5 engages the outer side surface 2B of the needle cylinder 2, as described below.

[0035] In more detail, the first appendix 13.5 forms a hook 13.15 adapted to engage a respective radial projection 63 that projects radially outwards from the outer side surface 2B of the needle cylinder 2 and is adj acent to a bottom surface of the respective radial groove 11.

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

[0037] More particularly, each hook 13.15 comprises a flank 13.16 that, when mounted, faces the axis A-A of the needle cylinder 2, is parallel thereto, and rests on a radially outer surface of the respective radial projection 63. Each hook 13.15 also includes an end edge 13.17 that, when mounted, is orthogonal to the axis A-A of the needle cylinder 2 and engages, in undercut and pressing fashion, a lower surface of the respective radial projection 63. Between the flank 13.16 and the end edge 13.17 an indentation or recess 13.18. The indentation or recess extends from the flank 13.16 in a radial outward direction, and is delimited by a concave edge formed in the metal sheet wherefrom the insert 3 is formed. The concave edge forms a portion 13.22 of the first appendix 13.5 that has a smaller thickness, i.e. a reduced width, at which point the appendix exhibits greater elastic flexural deformability. The enhanced flexural deformability of the hook formed in the first appendix 13.5 facilitates the assembly of the insert 13 on the needle cylinder 2.

[0038] In practice, the flank 13.16 of each hook 13.15 is parallel to the first portion 13.12 of the flank of the second appendix 13.6. When mounted, the flank 13.16 of each hook 13.15 and the first portion 13.12 of the flank of the second appendix 13.6 facing the first appendix 13.5 contact and press against the radial projection 63 and against the cylindrical end portion of the inner side surface of the needle cylinder 2, the cylindrical end portion being provided 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 appendix 13.6 of each insert 13, forms a gripping element for a removal 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 has, in this embodiment, an operating end that enters the recess 13.10 to lift the insert 13 from the inside of the needle cylinder 2, in order to release it from the working position. The pulling upward, in an approximately axial direction, of the second appendix 13.6 through the tool U causes the deflection of the second appendix, thus freeing the expansion 13.11 from the annular channel 61 where the expansion is engaged in undercut fashion.

[0040] The operation described above is facilitated by the inclination of the second appendix 13.6 toward the axis A-A of the needle cylinder 2, as a pull, exerted by means of the tool U, in an approximately axial direction toward the outside of the needle cylinder 2 causes the flexural deformation of the second appendix 13.6, and therefore the release of the insert 13.

[0041] The operation is further facilitated by the indentation or recess 13.18, which renders the first appendix 13.5 more flexible. Assembling and disassembling of the insert is achieved by flexural deformation of the first appendix 13.5, mainly at the restricted area 13.22, and of the second appendix 13.6. Therefore, as the flexural deformation is distributed across both appendices, each appendix undergoes less deformation compared to if only one of them were deformable. This method helps prevent the yielding of the insert.

[0042] Figs. 5 and 6 show a modified embodiment of an insert 13. Equal reference numbers indicate equal or equivalent parts. In the embodiment of Fig. 5, the flank of the second appendix 13.6 facing the first appendix 13.5 is divided into two portions 13.12 and 13.13 with the interposition of a step 13.20, so that the second appendix 13.6 has a narrower width in its distal portion, which facilitates flexural deformability and thus simplifies the assembly and disassembly of the insert.

[0043] Fig. 7 shows an example of an insert 13, which does not form part of the invention. In this example, the insert 13 includes a main body 13.1 with a top edge 13.2, defining a portion of the stitch formation surface, and a preferably rectilinear bottom edge 13.3. Extending from a first end of the main body 13.1 there is a first appendix 13.5 that projects from the bottom edge 13.3 and, when mounted, is oriented radially toward the outside of the needle cylinder 2. Each insert 13 also includes a second appendix 13.6 that extends from a second end of the main body 13.1 and, when mounted, is oriented radially toward the inside of the needle cylinder 2. The first appendix 13.5 and the second appendix 13.6 are approximately orthogonal to the bottom edge 13.3 of the main body 13.1.

[0044] In the example of Fig. 7, the second appendix 13.6 includes a distal end 13.7 that forms a terminal expansion of the second appendix 13.6. The terminal expansion 13.11 protrudes toward the first appendix 13.5 and faces radially outward, i.e. in a direction opposite to the axis A-A of the needle cylinder 2, when the insert 13 is mounted. When mounted, the terminal expansion 13.11 formed at the distal end of the second appendix 13.6 engages, in undercut fashion, an annular channel 61 formed on the inner side surface 2C of the needle cylinder 2, near the leading end 2A. In practice, the expansion 13.11 has the same function as the expansion 13.11 of the embodiment of Figs. 1 to 6. However, the second appendix 13.6 does not have an engagement element for engaging the U tool for releasing the insert 13 from the respective groove 11.

[0045] Also in the example of Fig. 7, the second appendix 13.6 has a flank that is oriented toward the first appendix 13.5. The flank extends from the bottom edge 13.3 of the main body 13.1. In more detail, starting from the bottom edge 13.3 of the main body 13.1, the flank comprises a first portion 13.12 orthogonal to the bottom 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; when mounted, the first portion 13.12 of the flank of the second appendix 13.6 contacts a cylindrical end portion of the inner side surface of the needle cylinder 2.

[0046] This tapered shape of the second appendix 13.6, combined, if necessary, with a recess 13.14 provided in the junction area between the bottom edge 13.3 and the second appendix 13.6, increases the flexural deformability of the second appendix 13.6 and facilitates the mounting of the insert 13 in, and the removal of the insert 13 from, the respective radial groove 11. Mounting of the insert 13 in the seat formed by the respective radial groove 11 occurs as already described with reference to the preceding figures.

[0047] Alternatively, the second appendix 13.6 of the insert of Fig.7 may be shaped with a step 13.20 along the inner side, i.e. the side facing the first appendix 13.5.

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

[0049] The embodiments described above and illustrated in the drawings have been explained in detail as exemplary embodiments of the invention. It will be clearly apparent to those skilled in the art that modifications, variants, additions and omissions are possible, without however departing from the principles, the scope of the concept and the teachings of the present invention as defined in the attached claims.

[0050] Fig.8 illustrates a side view of a modified embodiment of an insert according to the present disclosure. Identical reference numbers denote 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 in the main body 13.1 of the inserts 13 and forms a portion 13.24 of the second appendix 13.6 which is thinner, i.e. has a smaller width than the portion of the same appendix 13.6 where the first portion 13.12 of the flank of said first appendix oriented towards the first appendix 13.5. The thinner portion 13.24 of the second appendix 13.6 imparts higher elastic flexural deformability to the second appendix 13.6, making the assembly of the inserts on the needle cylinder easier.

Claims

1. A needle cylinder (2) for a knitting machine, wherein: the needle cylinder (2) comprises an outer side surface (2B), an inner side surface (2C) and a leading end (2A); sliding grooves (4) for the needles (3) are provided on the outer side surface (2B), parallel to an axis (A-A) of the needle cylinder (2); on the leading end (2A), a respective radial groove (11) is provided between each pair of adjacent sliding grooves (4); an insert (13) is housed in each radial groove (11), each insert (13) comprising a main body (13.1) with a top edge (13.2) and a bottom edge (13.3), the top edges (13.2) of the inserts (13) projecting from the respective radial grooves (11) and defining a stitch formation surface, and the bottom edges (13.3) resting on the bottom of the respective radial grooves (11); each insert (13) has a first radially outer appendix (13.5), extending from a first end of the main body (13.1) and engaging the outer side surface (2B) of the needle cylinder (2), and a second radially inner appendix (13.6), extending from a second end of the main body (13.1) and engaging the inner side surface (2C) of the needle cylinder (2); wherein a distal end (13.7) of the second appendix (13.6) includes a protrusion (13.11) that is oriented toward the first appendix (13.5); characterized in that the second appendix (13.6) of the insert (13) has a recess (13.10) forming a gripping element for a removal tool.

2. The needle cylinder (2) of claim 1, wherein the gripping element is formed at the distal end (13.7) of the second appendix (13.6).

3. The needle cylinder (2) of claim 2, wherein the distal end (13.7) of the second appendix (13.6) of each insert (13) includes a pair of fingers (13.8, 13.9) forming said recess (13.10).

4. The needle cylinder (2) of claim 2 or 3, wherein the protrusion (13.11) included in the distal end (13.7) of the second appendix (13.6) of each insert (13), when mounted, is oriented radially toward the outside of the needle cylinder (2) and engages, in undercut fashion, an annular channel (61) formed on the inner side surface (2C) of the needle cylinder (2).

5. The needle cylinder (2) of one or more of claims 2 to 4, wherein the second appendix (13.6) has a shape that tapers from a proximal end, proximate to the main body (13.1) of the insert (13), to the distal end, the tapered shape increasing the flexural deformability of the second appendix (13.6).

6. The needle cylinder (2) of one or more of the preceding claims, wherein the second appendix (13.6) of each insert (13) includes a flank that is oriented toward the first appendix (13.5) and extends from the bottom edge (13.3) of the main body (13); wherein the flank comprises, starting from the bottom edge (13.3) of the main body (13.1), a first portion (13.12) orthogonal to the bottom 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 (13.12) of the flank of the second appendix (13.6) contacts a cylindrical end portion of the inner side surface (2C) of the needle cylinder (2).

7. The needle cylinder (2) of one or more of the preceding claims, wherein the bottom of each radial groove (11) is orthogonal to the axis of the needle cylinder and, when mounted, the bottom edge of the main body (13.1) of each insert (13) is orthogonal to the axis (A-A) of the needle cylinder (2).

8. The needle cylinder (2) of one or more of the preceding claims, wherein the first appendix (13.5) of each insert (13) forms a hook (13.15) adapted to engage a respective annual groove (64) of the outer side surface (2B) of the needle cylinder (2), or a respective radial projection (63) that projects radially outwards from the outer side surface (2B) of the needle cylinder (2) and is adjacent to a bottom surface of the respective radial groove (11).

9. The needle cylinder (2) of claim 8, wherein each hook (13.15) includes a flank (13.16) that, when mounted, faces the axis (A-A) of the needle cylinder (2), and rests on a radially outer surface of the needle cylinder (2); wherein the hook (13.15) includes an end edge (13.17) that, when mounted, engages, in undercut and pressing fashion, the annular groove (64) or a lower surface of the respective radial projection (63); wherein preferably the flank (13.16) is parallel to the axis (A-A) of the needle cylinder (2) and the end edge (13.17) is orthogonal to the axis (A-A) of the needle cylinder (2); and wherein preferably each hook (13.15) includes a recess (13.18) between the flank (13.16) and the end edge (13.17) of the hook (13.15), the recess (13.18) extending radially outwardly beyond the flank (13.16), thus forming a section of increased flexural deformability of said first, radially outer appendix (13.5)..

10. The needle cylinder (2) of claim 8 or 9, when depending on at least claim 6, wherein the flank (13.16) of each hook (13.15) is parallel to the first portion (13.12) of the flank of the second appendix (13.6) facing the first appendix (13.5); wherein, when mounted, the flank (13.16) of each hook (13.15) contacts and presses against the outer side surface (2B) of the needle cylinder (2) or against the radial projection (63); and wherein the first portion (13.12) of the flank of the second appendix (13.6) contacts and presses against the cylindrical end portion of the inner side surface (2C) of the needle cylinder (2).

11. A single-cylinder knitting machine (1) including a needle cylinder (2) as claimed in one or more of the preceding claims.

12. An insert (13) for a needle cylinder (2) of a knitting machine (1), wherein the insert (13) includes a main body (13.1) with a top edge (13.2) and a bottom edge (13.3), wherein the top edge (13.2) is adapted to define a stitch formation surface when the insert is inserted in the knitting machine (1); and wherein the insert includes a first appendix (13.5), extending from a first end of the main body (13.1), and a second appendix (13.6), extending from a second end of the main body (13.1); wherein the second appendix (13.6) has a recess (13.10) forming a gripping element for a removal tool; characterized in that the distal end (13.7) of the second appendix (13.6) includes a protrusion (13.11) that is oriented toward the first appendix (13.5).

13. The insert (13) of claim 12, wherein the recess (13.10) forming the gripping element is positioned at a distal end of the second appendix (13.6).

14. The insert (13) of claim 13, wherein the distal end of the second appendix (13.6) comprises a pair of fingers (13.

8. 13.9) forming the recess (13.10).

15. The insert (1) of one or more of claims 12 to 14, wherein the second appendix (13.6) has a tapered shape from a proximal end, proximate to the main body (13.1) of the insert (13), to the distal end, the tapered shape increasing the flexural deformability of the second appendix (13.6).

16. The insert (13) of one or more of claims 12 to 15, wherein the second appendix (13.6) comprises a flank that is oriented toward the first appendix (13.5) and extends from the bottom edge (13.3) of the main body (13.1); wherein the flank comprises, starting from the bottom edge (13.3) of the main body (13.1), a first portion (13.12) orthogonal to the bottom 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).

17. The insert (13) of claim 16, wherein the second portion (13.13) of the flank of the second appendix (13.6) ends with said projection that is oriented toward the first appendix (13.5).

18. The insert (13) of one or more of the claims 12 to 17, wherein the first appendix (13.5) forms a hook (13.15) with an edge (13.17) facing the bottom edge (13.3) of the main body (13.1); wherein preferably the hook (13.15) has a flank (13.16) which is parallel to the first portion (13.12) of the flank of the second appendix (13.6) facing the first appendix (13.5); and wherein preferably the hook (13.15) includes a recess (13.18) between the flank (13.16) and the edge (13.17) of the hook (13.15), the recess extending radially outwardly beyond the flank (13.16) of the hook (13.15), and forming a section of reduced width and increased flexural deformability of said first appendix (13.5).