WO2005035850A1

WO2005035850A1 - System for changing the level of gauge of fabric obtained with rectilinear knitting machines and relevant method

Info

Publication number: WO2005035850A1
Application number: PCT/IB2004/003316
Authority: WO
Inventors: Benito Stoppazzini
Original assignee: Emm S.R.L.
Priority date: 2003-10-14
Filing date: 2004-10-12
Publication date: 2005-04-21
Also published as: ITBO20030596A1

Abstract

The system of the invention allows changing the level of fineness of the fabric in a rectilinear knitting machine (100). The machine (100) includes a pair of needle beds (10, 20), each comprising a plurality of removable sinkers (11, 21), intercalated with corresponding needles (12, 22). In a machine configuration for fine fineness, an abutment stem (13, 23) of the transversal rows of stitches being formed is inserted into holes (14, 24) made in the head of each sinker (11, 21). To change the actual fineness level of the machine (100), and obtain an actual larger fineness, a row of additional holes (15, 25) is made in an inner position relative to the holes (14, 24) in the sinkers (11, 21) of each needle bed (10, 20). The stems (13, 23) are inserted in such additional holes (15, 25), and one sinker (11, 21) is removed out of each group of adjacent sinkers. Moreover, the needles (12, 22) corresponding to the removed sinkers are deactivated.

Description

SYSTEM FOR CHANGING THE LEVEL OF GAUGE OF FABRIC OBTAINED WITH RECTILINEAR KNITTING MACHINES AND RELEVANT METHOD

SCOPE OF THE INVENTION The present invention falls within the technical field of the manufacture of knitting machines. In particular, the invention refers to a method and a system for changing the level of fineness, that is, the stitch size, of the fabric obtained with rectilinear knitting machines. 10 DESCRIPTION OF THE PRIOR ART As known, rectilinear knitting machines generally comprise a pair of needle beds, arranged opposed to one another and in a substantially symmetrical manner relative to a longitudinal 15 plane. A special carriage travels on the needle beds with an alternating rectilinear motion and in longitudinal direction relative to the same. The carriage carries suitable operating units that select a series of needles inserted into cross slits realised at regular 20 distances on the needle beds. By a suitable weaving program, a control unit manages the above operating units which provide' to the actuation of the needles in a sequence, so as to obtain the formation in series of the so-called fabric transversal row of stitches, that is, 25 rows of stitches forming it. At the stitch forming zone, the machine needle beds shape a sort of comb, between whose teeth the needles work. Such teeth consist of the hooked head of a series of sinkers arranged side by side, and seated in known manner at grooves obtained in the 30 needle bed front zone. A hole is made in the head of each sinkers. When the sinkers are in their position on the needle beds, the respective holes are aligned. A metal stem is inserted into the holes, which is therefore rectilinear and parallel to the corresponding stem present on the opposed needle bed. The two stems are intended to hold the stitch being formed in support. The distance between the two opposed stems and between two consecutive sinkers defines the fineness of the stitch formed by the machine, that is, the size of the stitch itself, and thereby the level of fineness of the fabric obtained by the same machine. To obtain a pleasant and balanced stitch, such distances must be suitably devised and defined during the machine design stage. In known knitting machines, the stitch fineness is a peculiar feature of each machine, since the distance between the two stems, and especially the distance between consecutive sinkers, is unchangeable. For the industrial user of these machines, this involves the disadvantage of having to provide for at least one machine for each stitch fineness of the fabrics to be manufactured. This involves considerable investments, overall dimensions and maintenance costs.

SUMMARY OF THE INVENTION The main object of the present invention is to provide a method for changing the fineness of the stitch in a rectilinear knitting machine. A further object of the invention is to provide a system for implementing the above method, wherein the operations required for changing the fineness of the stitch can be implemented easily and within reasonable time. Another object of the invention is to provide a system for changing the fineness of the stitch which should not substantially increase the complexity of the knitting machine and, as a result, the manufacturing cost of the same and its sales price. The objects mentioned above are fully achieved, according to the contents of the claims, by a method and a corresponding system for changing the level of fineness of the stitch in a knitting machine with double needle bed, such method comprising the execution of the operations for removing the abutment stems of the transversal rows of stitches being formed from the corresponding holes, selectively removing a plurality of sinkers from the corresponding needle beds for increasing the pitch between two consecutive sinkers, on which the fineness level depends, afterwards inserting the above stems into a series of additional holes made on the head of the sinkers, so as to increase the reciprocal distance between the stems, and for deactivating the needles corresponding to the removed sinkers .

BRIEF DESCRIPTION OF THE DRAWINGS The features of the invention, as will appear from the claims, are highlighted in the following detailed description, with reference to the attached drawings, wherein: figure 1 schematically shows a side view of the stitch forming zone of a knitting machine realised according to the invention, set up for a fine stitch fineness; figure 2 schematically shows a side view of the same machine, set up for a larger stitch fineness; figure 3 schematically shows a top view of a portion of the stitch forming zone of a needle bed of the machine of figure 1; figure 4 schematically shows a top view of a portion of the stitch forming zone of a needle bed of the machine of figure 2; figure 4 schematically shows a top view of a portion of the stitch forming zone of a needle bed of the machine of figure 2, set up for an even larger stitch fineness.

DESCRIPTION OF PREFERRED EMBODIMENTS With reference to figure 1, reference numeral 100 globally indicates a rectilinear knitting machine which comprises two opposed needle beds 10, 20. The working edges of needle beds 10, 20 are close to one another and are symmetrically arranged relative to a vertical plane. According to known construction methods of rectilinear knitting machines, a gap is provided between the two needle beds 10, 20 which defines a fabric transversal row forming zone. The fabric already formed is conveyed downwards, approximately at the above symmetry plane. With further reference to figures 3 and 4, the structure of a needle bed 10 shall be described, considering that the remaining needle bed 20 is totally symmetrical to the first one. In its most forward part, needle bed 10 comprises a plurality of sinkers 11, removably arranged into respective grooves realised in the needle bed body. Corresponding needles 12, also arranged into suitable seats obtained in the front part of needle bed 10, are intercalated between sinkers 11. During the formation of the fabric transversal rows, needles 12 are activated in a known manner by a carriage, not shown, during the alternating motion of the same along the needle beds, by suitably shaped cams. The carriage also provides to the distribution of the yarn 3 needed to form the fabric between needles 12. At its head 17, each sinker 11 has a hole 14. All holes 14 of the sinkers of a needle bed are aligned with one another. In the machine configuration shown in figure 1, holes 14 are crossed by a stem 13 adapted for acting as abutment for the stitch being formed. An additional hole 15, arranged at an inner position relative to hole 14, and thereby at higher distance from the above forming zone of the fabric transversal rows, is provided in head 17 of the sinkers 11. In a totally similar way (figures 1 and 2) , needle bed 20 comprises a plurality of sinkers 21 and of needles 22 intercalated thereinbetween. A hole 24 and an additional hole 25 are provided in head 27 of each sinker 21. In the machine configuration shown in figure 1, holes 24 are crossed by a stem 23. The distance between the above stitch abutment stems 13, 23, along with the pitch existing between two consecutive sinkers

11 of the needle bed 10, and thereby between two consecutive sinkers 21 of the needle bed 20, defines the stitch size, and thereby the level of fineness of machine 100. According to the present invention, with reference to figures 2 and 4, there is shown a different working configuration of machine 100. In the first place, such working configuration provides for the stem 13 of a needle bed 10 and the stem 23 of the opposed needle bed 20 to be respectively inserted into the additional holes 15 of the needle bed 10 and 25 of the needle bed 20, rather than in the holes 13, 23.

Moreover, a plurality of sinkers 11 has been removed from the needle bed 10. In particular, for each pair of adjacent sinkers

11, one sinker 11 is removed, so as to double the pitch existing between the same. Similarly, sinkers 21 are maintained in the needle bed 20, facing those maintained in the opposed needle bed 10. In this latter working configuration, since the distance between the two abutment stems 13, 23 of the transversal rows of stitches has increased, and also the pitch between two consecutive sinkers has increased, the size of the stitch formed by the machine 100, and therefore the actual fineness level of the same, have increased. That is, the stitch is larger than that realised with the working configuration described above, even though an identical dimensional ratio between height and width is maintained. The needles 12, 22 corresponding to the sinkers 11, 21 that have been removed can, optionally, be removed as well, or they can be kept inactive, that is, never brought in the process by a program for creating the fabric transversal rows using the new fineness . Preferably, in the working configuration corresponding to the larger fineness, also the needles 12, 22 corresponding to the sinkers 11, 21 maintained into position, are replaced with larger ones . Figure 5 describes a further working configuration of the machine 100, adapted for obtaining an even different fineness. In this case, the stem 13 is inserted into the holes 15 of the sinkers 11 and two sinkers have been removed, out of each group of three sinkers adjacent to one another. Also in this case, the needles 12 corresponding to the removed sinkers are deactivated. The same operation is carried out on the opposed needle bed 20. The pitch existing between two consecutive sinkers 11 is even more increased, and the stitch size increases as well. In this case, the variation of the fineness level is of the so- called "virtual" type, as the dimensional ratio between stitch height and width is changed. The method for changing the level of fineness of machine 100 according to the present invention provides for the execution of a sequence of fixed working steps. In particular, to increase the actual size of the stitch, with the machine 100 originally configured for the fine fineness level (figures 1 and 3), the procedure is as follows: in the first place, the stems 13, 23 are removed from the corresponding holes 14, 24. A sinker 11, 21 out of each group of two adjacent sinkers is then removed from the two needle beds 10, 20, so that sinkers 11, 21 facing one another are maintained operating in the two needle beds 10, 20. The needles 12, 22 corresponding to the operating sinkers 11, 21 are optionally replaced with larger needles, adapted for the new stitch size. The stems 13, 23 are then inserted into the innermost holes 15, 25. The programs that will use the new fineness level will of course provide for the deactivation of the needles 12, 22 corresponding to the sinkers 11, 21 that have been removed. The working steps described above are carried out to obtain the above further virtual fineness of machine 100, but removing two sinkers 11, 21 out of each group of three sinkers adjacent to one another in the needle beds 10, 20. Of course, the restoration of the fine fineness level is performed by carrying out the above working steps in the reverse order. The present invention advantageously allows obtaining rectilinear knitting machines capable of working with two different actual levels of fineness of the stitch. This allows having a smaller number of machines in a manufacturing line, types of fabrics that can be manufactured being the same. The change of the fineness level is also obtained with a simple and not difficult sequence of operations that can be carried out by an expert operator in reasonable time and therefore with limited machine downtimes. A further advantage is given by the fact that to obtain an actual stitch fineness variation, the knitting machine complexity is not substantially increased. It is understood that the above is described by way of a non-limiting example only. Therefore, possible changes and variants of the invention are regarded as falling within the scope of protection granted to this technical solution, as described above and claimed hereinafter.

Claims

1. Method for changing the level of fineness of the fabric in a rectilinear knitting machine, said machine (100) including a pair of opposed needle beds (10, 20) and with the respective working edges close to one another in a fabric transversal row of stitches forming zone, each of said needle beds (10, 20) comprising a plurality of removable sinkers (11, 21) , sided to one another and intercalated with corresponding needles (12, 22), and also comprising an abutment stem (13, 23) of said transversal rows being formed, inserted into holes (14, 24) made on the head of each of said sinkers (11, 21) and aligned with one another, wherein said level of fineness of the fabric depends on the pitch between two mentioned consecutive sinkers (11, 21) and on the reciprocal distance between said stems (13, 23) belonging to opposed needle beds (10, 20) , said method being characterised in that to increase the stitch size, it provides for the execution of the following operations: removing said stems (13, 23) from said corresponding holes (14, 24) ; selectively removing a plurality of said sinkers (11, 21) from said needle beds (10, 20) , for increasing said pitch; afterwards inserting said stems (13, 23) into a series of additional holes (15, 25) made in the head of said sinkers (11, 21) , so as to increase the reciprocal distance between said stems (13, 23); deactivating needles (12, 22) corresponding to said removed sinkers (11, 21) .

2. Method according to claim 1, characterised in that one of said sinkers (11, 21) is removed out of two sided sinkers.

3. Method according to claim 1, characterised in that two of said sinkers (11, 21) are removed out of three sided sinkers.

4. Method according to any one of claims from 1 to 3, characterised in that respectively facing sinkers (11, 21) are maintained in said two needle beds (10, 20) .

5. Method according to claim 1, characterised in that said needles (12, 22) corresponding to non-removed sinkers (11, 21) are replaced with larger needles.

6. System for changing the level of fineness of the fabric in a rectilinear knitting machine, said machine (100) comprising a pair of opposed needle beds (10, 20) and with the respective working edges close to one another in a fabric transversal row of stitches forming zone, each of said needle beds (10, 20) including a plurality of removable sinkers (11, 21), sided to one another and intercalated with corresponding needles (12, 22), and also comprising an abutment stem (13, 23) of said transversal rows of stitches being formed, inserted into holes (14, 24) made in the head of each of said sinkers (11, 21) and aligned with one another, wherein said level of fineness of the fabric depends on the pitch between two mentioned consecutive sinkers (11, 21) and on the reciprocal distance between said stems (13, 23) belonging to opposed needle beds (10, 20), said system being characterised in that at least one row of additional holes (15, 25), aligned with one another, arranged on the head of said sinkers (11, 21) , in an inner position relative to said holes (14, 24), is made in the sinkers (11, 21) of each needle bed (10, 20), the distance between the corresponding additional holes (15, 25) of said needle beds (10, 20) being therefore greater than that between said relative corresponding holes (14, 24), said additional holes (15, 25) being intended for seating said stems (13, 23), alternately to said holes (14, 24) for increasing, together with the selective removal of a plurality of said sinkers (11, 21) and with the deactivation of needles (12, 22) corresponding to the removed sinkers, the stitch size in the transversal tows of the fabric being formed, thus changing the level of fineness of said rectilinear knitting machine (100) .

7. System according to claim 6, characterised in that to increase the stitch size, there is provided the removal of one of said sinkers (12, 22) out of two sided sinkers.

8. System according to claim 6, characterised in that to increase the stitch size, there is provided the removal of two of said sinkers (12, 22) out of three sided sinkers.

9. System according to any one of claims from 6 to 8, characterised in that respectively facing sinkers (11, 21) are maintained in said two needle beds (10, 20) .

10. System according to claim 6, characterised in that to increase the stitch size, said needles (12, 22) corresponding to non-removed sinkers (11, 21) are replaced with larger needles .