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(11) | EP 2 602 364 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
| published in accordance with Art. 153(4) EPC |
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| (54) | IMPROVEMENT TO A PLATELESS CIRCULAR LOOM AND IMPROVED METHOD FOR PRODUCING JERSEY ON A PLATELESS CIRCULAR LOOM |
| (57) This abstract refers to a patent of invention for a circular loom without plate (1)
and process for weaving fabric in said loom belonging to the field of textile industry,
which have been enhanced to improve the textile structure of the fabric and the process
for weaving it; said loom is provided, in an assembly, with cylinder (3) having upper
surfaces (5) adjacent the slots (4) where needles (10) move and actuate as support
in the formation and descent of the knitting, replacing the plates; and device (30)
limiting the ascending movement of the fabric in the ascending movement of the needles
(10) comprising essentially radially movable fabric ascent limiting blades (32) which
timely enter between needles (10) and provide a mechanical obstacle to the fabric
ascending movement. |
[0001] This description relates to a patent of invention for a circular loom without plate and process for weaving fabric employing said loom belonging to the field of textile industry, which have been enhanced to improve the textile structure of the fabric and the process for weaving it.
[0002] Essentially, a circular loom comprises: a thread insertion subassembly generally arranged on top (cage); ring-shaped weaving subassembly itself arranged at an intermediate level (ribber); and a lower subassembly which receives the fabric.
[0003] In more traditional construction of the circular loom, the weaving subassembly comprises, essentially (fig. 1): cylinder (ring) 100 having all over its perimeter, a plurality of slots, each with an axial extension 101 outside the cylinder and radial upper extension 102 communicating with the axial extension; a plurality of hook-shaped head needles 103 and locking pawl, each one moving vertically in the respective axial extension of a slot, between an upper thread inserting position and a lower position where it completes knitting and interweaves with the last knitting woven; a plurality of plate pairs (blades) 104 lateral to respective needles and having three functions: fabric holding; knitting equalization; and forming a detachment plan; said plates move radially between an advanced position, where they are arranged inside respective radial extensions of the slot and cooperate with the needles, and a retreated position where they are at rest, outside the radial extensions of the slot; cam block 105 located in front of the lower section of the cylinder 100 and featuring a groove-shaped cam, comprised by ascending and descending sections, where the cam follower projection provided in the bottom of the needle is geared; and plate supporting and moving assembly located in front of the upper section of the cylinder 100 and comprising: a plate-holder block 106 with radial supporting grooves and plate guide; and a cam block 107 in whose cam the plates are geared.
[0004] The loom with the weaving subassembly as described above produces a knitted fabric 150 consisting of: (fig. 2) longitudinal stripes 151 with more threads; and longitudinal stripes 152 interspersed with those with fewer threads. Stripes with fewer threads are formed as a result of the plates in a manner known in the art.
[0005] In another embodiment, the circular loom has no plate. According to such construction, the weaving subassembly (ribber) comprises, essentially (fig. 3): cylinder 200 having a plurality of external axial slots 102 arranged all over the perimeter; and upper surfaces 102 adjacent the slots, which actuate as support in the formation and descending movement of the knitted fabric, in replacement of the plates; a plurality of hook-shaped needles 203 and locking pawl, each moving vertically in the respective axial slot 201, between an upper thread inserting position and a lower position where it completes the weaving of the knitted fabric; and cam block 204 located in front of the upper section of the cylinder 200 and having a groove-shaped cam where the cam follower projection provided in the lower part of the needle is geared.
[0006] The loom equipped with the above-described weaving subassembly without plate produces a knitted fabric 250 (fig. 4) with uniform longitudinal stripes 251 because of the lack of plates.
[0007] However, and despite the non-plate circular loom produces a better textile quality fabric, it presents a difficulty that would be desirable not to occur.
[0008] Therefore, the loom needles 203 have a descending course extending from an upper position, where a new warp thread is inserted in the needle head and from which it carries the new warp thread downwards; intermediate position at which the new warp thread is interwoven with the last knitted fabric supported on upper supporting surfaces 202 of the cylinder 200, replacing the plates, where said new warp thread is plied and a new knitting is formed; and lower position, where the new knitting is finished and at which the ascending course starts. In the ascending course of the needle and before the head crosses the last knitted fabric; said last knitting and all fabric take a radial step so the last knitting leaves the upper supporting surfaces 202 of the cylinder 200 and the new knitted fabric moves radially too, and is kept crossed by the needle body and then it becomes supported by said surfaces, while the needle 203 follows up to the upper point, where it receives the new warp thread and a new cycle begins.
[0009] Depending upon the tension of some knits on the respective needles 203 and/or friction between these latter and the knitting and/or other factors, the new knit, so far supported by the supporting surfaces 202, and the whole fabric, can be pulled up by the needles 203, which may deform or even break the new knitting or others. Currently, this problem is solved by means of a strict follow-up of the operation by the machine operator, and when such phenomenon happens, the operator puts his hand between the threads and manually pushes down the fabric, and/or such problem is solved by inserting the hairs of a brush between needles and pushing down the fabric.
[0010] This way of solving the trouble is cumbersome and may be ineffective in case it is not timely detected.
[0011] Therefore, the objective of the present patent of invention is to provide an improved loom and weaving process to overcome the fabric ascending problem, without the need of manual intervention by the operator, as currently happens.
[0012] Another objective is to provide an improvement that, besides overcoming the problem, requires no highly complex construction or manufacture which could render the invention uninteresting.
[0014] Another objective is to provide an improvement that can be incorporated, preferably in single ribber circular looms, for the manufacture of comfortable and light knitted fabrics with elasticity in two directions, perfect vanisé and free from vertical streaks.
[0015] Therefore, in view of the aforementioned drawbacks and aiming at overcoming them and achieving the related objectives, an improved circular loom without plate and improved process for weaving knitted fabric in circular loom without plate object of the present patent of invention were developed, whose construction, working and advantages are described below based on the attached drawings, in which:
Fig. 1 shows a schematic detail of a weaving subassembly (ribber) of a conventional circular loom with plate;
Fig. 2 shows an enlarged schematic detail of a section of the knitted fabric obtained with the loom of the above figure;
Fig. 3 shows a schematic detail of a weaving subassembly (ribber) of a conventional circular loom without plate;
Fig. 4 shows an enlarged schematic detail of a section of a knitted fabric obtained with the loom of figure three;
Fig. 5 shows a schematic detail of a weaving subassembly (ribber) of a circular loom of the type without plate incorporating the improvement object of the present patent; and
Figs. 6 and 7 show two stages of operation of the improved loom, in the needle ascent and descent, respectively.
[0016] According to the provisions of the invention and as shown by the above-mentioned figures 5 to 7, the circular loom 1, object of the present patent of invention, comprises essentially: the usual upper cage subassembly (not shown) for supporting the reels and unwinding the warp threads; an intermediate weaving subassembly (single ribber) 2 shown in figures 5 to 7; and lower subassembly for receiving the fabric (not shown).
[0017] The weaving subassembly 2 comprises, essentially (fig. 5): cylinder 3 having a plurality of axial slots 4 arranged externally and all over the perimeter; upper surfaces 5 adjacent the slots 4, which work as support for the formation and descent of the knit, replacing the plates; said cylinder further comprising an inner slope surface 6 extending from the upper surfaces 5 and supporting the fabric already knitted; a plurality of needles 10 with hook-shaped heads 11 and a hinged pawl 12 for locking the head; each needle moving vertically in the respective axial slot 4; and a cam block 20 located in front of the lower section of the cylinder 2 and featuring a groove-shaped cam (not shown), where the cam follower projection (not shown) provided in the lower part of the needle 10 is geared; said cam moving the needle up and down in a manner known in the art. The present improvement consists of providing the above-described weaving subassembly of the type without plate 2, with a fabric ascent limiter 20 in the ascending movement of the needles 10.
[0018] Said fabric ascent limiter 30 comprises essentially: a plurality of movable blades 31 that limit the ascending movement of the fabric, arranged in vertical plans radially to the weaving subassembly 2 and that pass through needles 10, each blade 31 consisting of an upper horizontal tip 32 having a lower limiting edge 33 located in the horizontal plan slightly above the upper supporting surfaces 5 of the cylinder 3, which replace the plates; said movable, radial fabric ascending limiting blade 31 featuring an end 34 opposite to the tip 32 featuring a cam follower projection 35; said fabric ascent limiter 30 further comprises a blade supporting 40 and moving 31 assembly comprised essentially by a lower supporting block 41 and a blade guide 31; and upper cam block 42 having a cam groove 43 where the cam follower projections 35 of the blades 31 are geared; said cam groove 43 and cam follower projections 35 are arranged so the blades 31 move following a radial trajectory between: 1)- An advanced position (fig. 6), where the fabric ascending limiting tips 32 of said plates 31 are interspersed between needles 10 and above the fabric knits "M" supported on supporting surfaces 5 of the cylinder 3 so that the lower fabric ascending limiting edges 33 of said tips 32 limit the ascending movement of said knits "M" and of the fabric as a whole; and 2)- A retreated rest position (fig. 7) in which said tips 32 are outside the needles 10, allowing the new warp thread to be inserted and pulled down by the needle in the formation of the new knitting.
[0020] The cam and guide assembly 40 of the fabric ascent limiters 31 may be either fixed movable or fixed, which allows overriding or not the actuation of the ascent limiters 31, where desired.
[0021] The weaving subassembly 2 of the type without plate featuring the above-described fabric ascent limiter 30, performs an improved weaving process, also object of protection as claimed in this patent, comprised, essentially by the usual steps of:
1)- Inserting the new warp thread into the needle head: - This step takes place in the end of the ascending course and start of the descending course of the needle, where the pawl is at a hinged position downwards and opens the needle head; the needle receives the warp thread; the needle body crosses the last knitting woven; this latter is supported on the upper cylinder supporting surfaces, replacing the plates; and the rest of the fabric, from the last knitting, is supported on the inner surface of the cylinder and hangs down from the surface up to the lower section of the loom;
2)- New knitting formation: The needle carrying the new warp thread goes down and crosses the last knitting during which the pawl, by interference of the last knitting is articulated upwards, closes the head and holds the new warp thread; said new warp thread, by interference of the lateral sections of the last knitting, is plied and interlaced with said last knitting; and as the needle continues to go down carrying the thread, the thread is plied forming the new knit, and in the lowermost position of the needle, the new knit is completed and the pawl is released, articulating downwards and opening the needle head;
3)- Fabric moving ahead: The needle starts its ascending course from the lowermost position, and before its head crosses the last knitting, this latter and the rest of the fabric move ahead radially, and thus the rest of the fabric goes down; the last knitting leaves the supporting surface of the cylinder replacing the plates; the new knit is kept interlaced by the needle body, moving ahead radially and is arranged on said supporting surfaces of the cylinder, replacing the plates; and the needle continues to go up and crosses the new knit up to reaching again the highest point of the course, where the new thread is inserted and a new cycle begins.
[0022] The improvement introduced in the above-described weaving process comprises providing it with the following additional step: 4)- Limitation of the fabric ascending movement during the ascending course of the needles, comprised by:
1)- Introduction of the radially movable fabric ascent limiters, to an advanced position between needles during their ascending course so that said limiters are arranged above the new knits supported on the supporting surfaces of the cylinder, replacing the plates, providing a mechanical obstacle to the ascending movement of said new knits and fabric as a whole; and
2)- As the needle reaches the end of its ascending course and receives the new warp thread, removing the radially movable fabric ascent limiters from the needles, and taking them to a retreated position, to make way for the new thread carried by the needle.
[0023] Therefore, the present improvements in circular loom without plate and weaving process carried out with such circular loom solve the drawback found with the usual circular looms without plate, once it introduces a limit to the fabric ascending movement, thus preventing the fabric from deforming or being torn during the ascending movement of the needles, without the need of any manual interference by the loom operator, as usually happens.
[0024] Using fabric ascent limiters allows knitting directly using the ribber profile of the cylinder and keeps the fabric low in the initial phase of the work, as needed to reknit, further allowing interweaving the fabric, in the ascending course of the needle, after knitting, without the help of a fabric puller. As no fabric puller is required, the construction of the loom is simplified, as desirable, thus facilitating its manufacture and favoring cost savings.
[0025] The solutions proposed by the present improvements require a relatively simple construction, according to the construction technique applicable to circular looms, and it is cost-effective according to other objectives of the invention.
[0026] With the present solutions it is possible to provide single ribber circular machines for the manufacture of comfortable, light and elastic knitted fabrics in two directions, with perfect vanisé and free from vertical streaks, according to another objective of the invention.
[0027] According to the above-described basic construction, the circular loom without plate and weaving process carried out with it, objects of the present patent, may receive changes in materials, dimensions, construction and/or functional configuration and/or ornamental details, or steps and parameters of the process without departing from the scope of protection claimed.
1)- An advanced position in which the fabric ascending limiting tips (32) of said plates (31) are interspersed between needles (31), above the fabric knits "M" supported on the supporting surfaces (5) of the cylinder (3) so that the lower fabric ascending limiting edges (33) of said tips (32) limit the ascending movement of said knits "M" and of the fabric as a whole; and
2)- A retreated rest position, where said tips (32) are outside the needles (10), allowing passing the new warp thread pulled down by the needle in the formation of the new knit.
1) Inserting the new warp thread into the needle head, where a new warp thread is fed to the needle head at the highest position;
2)- Forming the new knitting in which the new warp thread is inserted, interlaced with and plied in the last knitting woven supported on the upper supporting surfaces of the cylinder, replacing the plates, and forming the new knitting; and
3)- Moving the fabric ahead, where the whole fabric and last knitting take a radial step and the last knitting leaves the supporting surfaces of the cylinder replacing the plates; the new knit is kept crossed by the needle body, moves radially ahead and is arranged on said supporting surfaces of the cylinder, replacing the plates; and the needle is kept going up and crossing the new knit up to an upper position to insert the new warp thread and a new cycle begins characterized in that it provides the additional step of:
4)- Limiting the ascending movement of the fabric in the ascending course of the needles, comprised by:
1)- Introduction of radially movable fabric ascent limiters, to an advanced position between the needles during their ascending movement, so that said limiters provide mechanical obstacle to the ascending movement of said new knits and of the fabric as a whole; and
2)- As the new wrap thread is inserted in the needle, the radially movable fabric ascent limiters are removed from the needles to a retreated position to make way for the new warp thread carried by the needle.