EP0261048A2 - Improvements introduced in the needle plates of rectilineal knitting machines - Google Patents

Abstract

The present invention refers to a series of impro­vements in the needle plates (3) of rectilineal knitting machines, intended to minimize the wearing effects caused by the needles in said needle plates (3) in the normal operation of the knitting machine, especially with stiff and little elastic yarns.

Specifically they consist in the disposition, on each of the needle plates of the machine, of a longi­tudinal channel in which it is coupled, with an ex­changeable character, a milled ruler (5) on which are es­tablished beds for the needles in continuity with tho­se of the rest of the needle plate (3), being these rul­ers (5) of a material with a great hardness and being in­tended to withstand the friction effects produced by the needles (1) in their alternative movement, due to the traction or stretching caused in turn by the stret­cher of the fabric (4).

Description

OBJECT OF THE INVENTION
• The present invention refers, as expressed by the ti­tle of this specification, to a series of improvements introduced in the needle plates of rectilineal knitt­ing machines, improvements oriented towards the obtent­ion of a further resistance to wearing on the part of said needle plates, before the alternative movement of the needles in their corresponding beds, and especially with the use of new fibers which give rise to very sti­ff and little elastic yarns and which require a great traction effort on the part of the stretcher of the fa­bric.
ANTECEDENTS OF THE INVENTION
• As it is known, in the needle plates of the rectilin­eal knitting machines are defined a plurality of chann­els, slots or beds for said needles, in which these move alternatively in the operational process of the machi­ne. At present, the weaving elements of this type of machines work at the limit of possibilities and wearings allowed, due especially to the use of new artificial fi­bers and their mixes with natural fibers, which have caused the creation of very stiff and little elastic yarns, to weave a practically infinite range of new samples, possibilities thanks to the incorporation of electronics in the programming of said machines. All of this has caused that the plates or beds of needles of the conventional machines, the main weaving organ of same, suffer a premature wearing not only on the side walls but also in the depth of the slots or beds for the needles, which determinate plays, that cancel the operativity of the machine.
• This wearing results very acute in the upper part of the needle plates, as it is here where the slots have a minor section, and is caused by the very movement of the needles which, to reach the utmost uprise, suffer a traction towards the inside of the machine, and down­wards, due to the stretching of the very knits or meshes which configurate the fabric that is being weaved.
• In accordance with this problem, the evident and most adequate solution, in principle, would be the man­ufacture of the needle plates with a material with a hardness the same or higher than that of the needles. This solution, which may be accepted from the theore­tical point of view, results impossible in practice as the manufacture, under the previously stated conditions, of some elements of so much magnitude and complexity as are the needle plates, would imply an increase in costs, so considerable, that it would not be admitted by the market.
DESCRIPTION OF THE INVENTION
• With the improvements that the invention proposes, this problem is solved at full satisfaction, not only from the operational point of view, but also from the economic point of view.
• Therefor and in a more concrete mode, such improve­ments consist in the disposition, on each of the needle plates, of a ruler, previously mechanized, through dri­llings which determine slots coincident, not only in their section but in their passing or hub, with that of the slots existing in the needle plates of the ma­chine to which such rulers are intended, so that a perfect continuity is established between the slots of the base needle plate and the slots of the comple­mentary ruler.
• The material used for the manufacture of these rul­ers will have the adequate degree of hardness, approxi­mately of a value twice than that of the material used for the manufacture of the needle plates, with which optimal duration and yield are obtained.
• Said rulers will be implanted in guides operatively made in the needle plates, in their high area, that is, in that with the greatest wearing.
• In accordance with another improvement of the inven­tion, the cited rulers are mounted on their guides with an exchangeable character, for which, before an event­ual wearing of same, they can be easily replaced for new ones.
• Therefore and in accordance with the improvements preconized it is attained, on one side, the enlarge­ment of the useful life on the needle plates, on min­imizing the wearing suffered by same, and on the oth­er, and on reaching such a wearing situation, only the rulers should be changed and not the complete nee­dle plates, as it happens in the conventional machi­nes, with the consequent and favourable repercussion, economic, that this means not only from the point of view of materials or replaced elements in the machine but also from that of labour necessary to carry out such substitutions.
DESCRIPTION OF THE DRAWINGS
• To complement the description which is being made and in order to help to a better understanding of the characteristics of the invention, we enclose herewith as an integral part of this specification, a set of drawings in which, with an illustrative and not lim­itative character, the following has been represented:
• Figure 1.- Shows a schematic cross sectional view of the needle plates of a rectilineal knitting machi­ne made in accordance with the improvements object of the invention, in which the needles have been repres­ented in the weaving position and in the utmost upri­se position.
• Figure 2.- Shows the same view of the previous fig­ure in the position of transfer of mesh.
• Figure 3.- Shows a plane view of one of the needle plates, in which it is noted the specific positioning set forth for the complementary ruler, on which the invention is fundamentally centered.
• Figure 4.- Shows a cross sectional view of the nee­dle plate shown in the previous figure.
• Figure 5.- Shows an extended view of the ruler, whi­ch now appears in an isolated mode.
• Figure 6.- Finally, shows a profile of said ruler duly coupled in the corresponding slot.
PREFERENT EMBODIMENT OF THE INVENTION
• In the previously stated figures and more concrete­ly in figures 1 and 2, it can be seen the needles 1, located on their corresponding channels or beds 2 of the needle plates 3, in their position of utmost upri­se which correspond to the weaving and to the transfer respectively. To reach said position, the needles, in their up and down movements, must overcome the resist­ance offered to such movements by the very fabric, whi­ch hangs from them and which is permanently committed to a stretching effect, in a downward sense, concrete­ly in that of the "G" arrows shown in the cited figures 1 and 2, stretching caused by the traction of the stret­cher of the fabric, not represented in such figures.
• This traction in the downward sense of the fabric 4 has a repercussion, thanks to a vectorial decomposit­ion, in forces in the side walls and in the bottom of the slots or beds 2 for the needles, especially in the extreme higher area of same.
• Well then, in this higher area of the needle plates 3 and in accordance with one of the improvements preco­nized, there is a ruler 5, duly drilled, so that in sa­me are established slots 6 which set forth a perfect continuity with the slots 2 of the needle plates 3, not only on which refers to their bottom 6 but also to the­ir side walls 7-7ʹ.
• This ruler 5 will be obtained in a material consid­erably harder than that which participates in the str­ucturation of the needle plates 3, with which said ru­ler 5 will be the one to support practically in total the effects of the friction of the needles 1 in their alternative movement along the slots or beds 2-6, sup­porting these wearing effects, not only their bottom 6 but also their side walls 7-7ʹ during a time consi­derably longer than that which a conventional needle plate is able to stand, as said rulers 5 are obtained on basis of a material with a great hardness.
• On the other side, it has been provided that the ru­lers 5 as observed with full clearness in the view of figure 6, adopt a dovetail profile which allows an ut­most easy and simple mounting in the corresponding nee­dle plate 3, concretely on a guide 8 provided to that purpose in same, and with a complementary section, be­ing unmovably fastened in longitudinal sense with the cooperation of fastening pins 9 which pass through the holes 10 set forth at the ends of said rulers 5.
• On the longitudinal view of figure 3 it can be not­ed the positions of weaving and transfer for the nee­dles 1, concretely that of weaving to the left and of transfer to the right. It is also noted in this figure, represented schematically, the meshes 11 of the fabric and their special inclination towards the inside of the machine which determines a side effort of the needles in their movement through the corresponding beds or slots, which determines the trend to the simultaneous wearing, not only from its bottom but also from its side walls.
• Thus, and in accordance with the improvements pre­conized, these efforts are suffered and absorbed by the milled rulers 5 which due to their hardness, min­imize the effects of wearing and for their exchange­able character makes practically indefinite the use­ful life of the needle plates.
• It is not considered as necessary to extend fur­ther this description so that any expert in the sub­ject understands the scope of the invention and the advantages derived from it.
• The materials, shape, size and disposition of the elements will be susceptible of variation, provided this does not mean an alteration to the essentiality of the invention.
• The terms under which this specification has been described must always be taken in a broad and not lim­itative mode.

Claims (3)

1.- IMPROVEMENTS INTRODUCED IN THE NEEDLE PLATES OF RECTILINEAL KNITTING MACHINES, which having as purpose the prolongation of the useful life of such needle pla­tes, versus the wearing caused by the needles in their corresponding beds or slots before the use of very sti­ff and little elastic yarns, which require a great load of stretching of the fabric, are essentially character­ized in that they consist in the disposition, on each of the cited needle plates, and in the high area of sa­me, that in which the efforts are more ample, of an ex­changeable ruler, milled, so that it incorporates slots formally, dimensionally and positionally coincident with those of the needle plate, to establish a perfect conti­nuity with the latter, in the conformation of the beds for the corresponding set of needles.

2.- IMPROVEMENTS INTRODUCED IN THE NEEDLE PLATES OF RECTILINEAL KNITTING MACHINES, as per claim 1, charac­terized in that the cited rulers are made of a material of a great hardness, considerably greater than that of the material which constitutes the needle plates.

3.- IMPROVEMENTS INTRODUCED IN THE NEEDLE PLATES OF RECTILINEAL KNITTING MACHINES, as per the previous cla­ims, characterized in that the cited milled rulers ad­opt a dovetail profile, which facilitates their mount­ing and replacement on complementary guides of the nee­dle plates, said rulers being fastened in their defini­tive position of mounting, with the cooperation of fas­tening pins, passing through extreme holes of the rulers and which are fitted to the very needle plates.

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