EP1055770A1

EP1055770A1 - Verifying machine for cloth inspection

Info

Publication number: EP1055770A1
Application number: EP00110878A
Authority: EP
Inventors: Paolino Gastoldi
Original assignee: LA MECCANICA COSTRUZIONE MACCHINE TESSILI SpA
Current assignee: LA MECCANICA COSTRUZIONE MACCHINE TESSILI SpA
Priority date: 1999-05-28
Filing date: 2000-05-23
Publication date: 2000-11-29
Also published as: ITMI990342U1; ITMI990342V0; IT246755Y1

Abstract

A verifying machine (1) for cloth inspection is disclosed, which comprises a display device (15) for a cloth (4) to be inspected which has a support and guide surface (16) for the cloth (4) forming a loop bent outwardly of the verifying machine (1), to impose a convex trajectory to the cloth (4).

Description

The invention relates to a verifying machine for cloth inspection in general, such as knitted fabrics, elastic materials, shuttle-woven fabrics, for example.
The verifying machine is of the type comprising a device for displaying a cloth to be inspected which is provided with a surface for supporting and guiding the cloth itself, as specified in the preamble of Claim 1.
It is known that a step of the greatest importance in cloth production is inspection of said cloths, before they are marketed, in order to identify and eliminate possible defects such as weft or warp errors, spots, pulled threads, tearing effects or others.
This inspection is carried out by appropriate textile machines, named verifiers, that can have an independent location or more frequently are inserted in a plant carrying out several different operations.
For instance, the plant in which the verifying machine is inserted can, on the whole, carry out several different operations on the cloths such as unwinding and re-winding into rolls, measurement, cutting, defect marking, defect recording on expressly-arranged computers, weighing, taping, labelling, roll unloading and also sending of said rolls to packaging.
Some of these operations can be directly carried out by the verifying machine that can be provided with various accessories such as metre counters, a weighing apparatus, a defect-marking apparatus or an apparatus capable of applying defect-marking labels, a rolling machine or others.
The essential function of the verifying machines is however that of enabling an operator to carry out an easy and efficient direct inspection of a cloth, to visually find out all possible defects of same that must be eliminated or may lead to discarding of a cloth.
For the purpose, the most important part of this machine is a display device for the cloth arranged close to a wide exposition region of the machine and capable of causing passage of the cloth before an operator.
In known verifying machines the display device comprises one or more end rollers that make the cloth pass over a support and guide surface placed between the rollers and embodied by one or more verification surfaces which are perfectly and uniformly levelled and lit, and turned towards a platform or site where the presence of an operator is provided.
As a matter of fact, verifying machines have various structures on the whole, but they can be immediately recognised due to the presence of a display device looking like a big blackboard panel generally disposed in an almost vertical position.
The cloth runs along the verification surface, being conveyed by said end rollers, at a greatly varying speed depending on the particular circumstances, which speed can for example reach sixty-one hundred metres per minute.
The running speed is at all events maintained as high as possible so that a high production level can be achieved and consequently costs connected with the inspection operations can be reduced.
It is therefore apparent that the task of an operator examining a cloth has a great incidence on the production levels, the operator's task being also of difficult accomplishment due to the fact that the cloth is caused to run very quickly.
Many efforts have been made to facilitate the operators work and, as a result, the inspection efficiency and quickness.
For instance, the verification surface has been enlarged so that it may occupy a major portion in height of the verifying machine and the possibility of moving the cloth back and forth has been contemplated so that possible cloth lengths giving rise to margins of uncertainty may be examined again.
Lighting too has been improved by arranging several lamps facing the verification surface, to increase lighting uniformity and intensity.
In addition, the cloth is driven by the end rollers placed at the ends of the verification surface, in such a manner that formation of creases on the cloth is avoided as much as possible, since these creases would alter the operator's impressions.
It is to be pointed out that creases can easily take place on the verification surfaces. In fact, the cloth has a tendency to fall upon itself and this tendency can be counteracted if the cloth is kept taut through a fine adjustment of the end roller rotation; the rotation adjustment must be correlated both with the type and weight of the cloth being worked and with the feed speed of the latter.
In spite of the efforts made by the verifying machines' constructors, creases can at all events take place and in addition the visual inspection of the cloths is still a critical and difficult operation.
It is therefore desirable to make said visual inspection still easier without on the other hand slowing down the running speed of the cloth because the production rates would be reduced, and without further enlarging the verification surface, because this expedient would bring about oversizing of the whole machine.
Furthermore, not completely satisfactory is control on stretching of the cloth which must be caused to move forward very quickly without creases and while keeping a running direction close to the vertical one; in fact the vertical direction is the one that more easily makes the cloth fall upon itself.
Under this situation, the general aim of the invention is to devise a machine capable of substantially obviating the mentioned drawbacks.
The above aim is achieved by a verifying machine for cloth inspection as claimed in the annexed claim 1. Preferred embodiments are set out in the dependent claims.
Description of a preferred embodiment of a machine in accordance with the invention is now given, by way of non-limiting example, with reference to the accompanying drawings, in which:
Fig. 1 shows the machine taken as a whole and inserted in a plant for dividing cloths into rolls; and
Fig. 2 shows a portion of the machine in Fig. 1 in which a device for displaying a cloth to be inspected is arranged. With reference to the drawings, the verifying machine is generally identified by reference numeral 1.
The machine 1, as shown by way of example only, is inserted in a plant 2 comprising, upstream of the machine itself, a delivery apparatus 3 to feed a cloth 4 gathered to form a big roll 5.
Disposed downstream of the machine 1 is a winding unit 6 wherein the cloth 4 is divided and wound into several rolls 7, the cloth being turned over and over on cylinders or cores 8.
Cylinders 8 are automatically supplied and the winding unit 6 for instance carries out the following operations that however do not concern the present invention: positioning of a cylinder 8, drawing-in on cylinder 8 of the cloth 4 coming from the verifying machine 1, gradual winding of the already inspected cloth 4.
Winding is carried out at a rolling-up station 9 in which the roll 7 being formed is tangentially moved and supported by two winding rollers 9a.
When winding has been completed, roll 7 is ejected towards an end station 10, cloth 4 is cut and finally roll 7 is taped, weighed, labelled and unloaded, whereas upstream formation of a new roll 7 of cloth 4 begins, which cloth comes from the verifying machine 1 and has already been inspected by said machine.
A winding unit of the type briefly described above is the object of the European Patents No. EP-B-0 374 871 and No. EP-B-0 374 872 in the name of the same Applicant.
The machine 1 has an outer casing 11 into which cloth 4 fed from the big roll 5 is driven to move forward by means of idler rollers, with possibility of reverse motion, and also measured and stored in a storage unit 12 compensating for possible advancing unbalances of cloth 4.
Other functions that in plant 4 are fulfilled by the delivery apparatus 3 and the winding unit 6 can be absorbed and concentrated into the machine 1.
At all events, cloth 4 is conveyed towards the upper end of a side 11a of casing 11 opposite to that facing the big cloth roll 5 and therefrom it is caused to move down to a wide exposition region 13 close to a platform 14 on which the presence of an operator is provided.
Platform 14 is located between the verifying machine 1 and the winding unit 6 and cloth 4 is caused to pass under platform 14.
A display device 15 is inserted in the exposition region 13 and it is adapted to impose a convex trajectory to cloth 4, so as to define with the cloth itself a loop bent outwardly of the machine 1.
The display device 15 comprises a support and guide surface 16 for the cloth 4 to be inspected which is fixed and has a convex shaping, but it may possibly comprise a support and guide surface 16 fully or partly defined by a roller projecting outwardly of the machine 1 and advantageously movable together with the cloth. At all events the device 15 extends between coplanar end sections, which are in particular parallel to each other and perpendicularly transverse to the cloth movement direction.
These end sections, in the embodiment shown, are substantially defined by an upper roller 17 and a lower roller 18 movable with cloth 4.
The convex trajectory imposed to cloth 4 by the display device 15 has, with respect to a reference plane 19 passing through said end sections or close thereto, a portion of maximum projection of rounded shape.
Preferably the portion of maximum projection is disposed centrally and symmetrically of the display device 15, although it is apparent that other positions are possible, in particular if a particular position with respect to an observer is wished for said maximum projection.
The convex trajectory may have an ogival or parabolic shape or be in the form of a pocket, but it is preferably defined by a support and guide surface 16 shaped as a cylindrical-surface portion.
It is also clear that the loop described by cloth 4 in the drawings is limited and connected to the overall drawing of the machine 1, but this loop can be so arranged as to greatly project from machine 1.
Shown in the figures is also a lighting apparatus which in an original manner is combined with the convex trajectory of the cloth.
This lighting apparatus is preferably defined by a first light source 20 disposed externally of the machine 1, on the operators side and turned towards the support and guide surface 16, and by a second light source 21 disposed under the cloth to be inspected and preferably flush with the reference plane 19, when the support and guide surface 16 is at least partly transparent.
A feature of the first light source is that of being substantially localised, in a manner adapted to define differently-lit cloth areas or regions, although in the presence of a strong lighting.
The combination of a localised light source and a convex trajectory for cloth 4 in fact leads to creation of a series of several lighting regions thereon, which are different from each other in terms of light intensity and incidence of the light rays.
Operation of the verifying machine 1, described above mainly as regards structure, is as follows.
Cloth 4 supplied from the delivery apparatus 3, is brought, after appropriate operations known in themselves, to the display device 15 so that it passes before an operator standing on platform 14.
This operator must quickly identify possible defects on the cloth such as waft and warp errors, spots, colour irregularities, pulled threads, tearing effects or abrasions, etc. before cloth 4 reaches the winding unit 6 where different rolls 7 of relatively reduced sizes are formed.
The characteristic and distinctive features of the display device greatly facilitate the operators task.
It is to be pointed out that the cloth easily keeps a wall-taut arrangement on the convex surface: due to convexity, the cloth does not fall upon itself which will give rise to creases.
Cloth 4 is practically wall supported by the support and guide surface 16 and in addition, as the cloth travels over a curved surface, it has a tendency to open wide and not to become more compact and get squashed.
It is therefore easier to avoid creases that are more likely to deceive an observer.
In addition, convexity, above all if it is stressed even to a greater extent than shown in the drawings, makes the cloth travel longer on the length in sight, and therefore the available time for the operator to detect a local defect is increased, the machine 1 sizes and the cloth running speed being the same.
Above all, the cloth does not run in a linear manner on a flat surface, with a uniform "blackboard effect" that in fact reduces the operators attention, but on the contrary it moves partly towards the operator highlighting a possible defect to a maximum extent in the region where the maximum projection takes place. Thus a sort of "lens effect" occurs, which will facilitate inspection and stimulate the operators attention.
It should be also pointed out that the convex trajectory and the light that from a first external localised source strikes on the curved surface cause, as a result, formation of a region of maximum lighting which may be brought to coincide with the region of maximum projection, to greatly increase said "lens effect".
Lighting is also advantageous due to the different incidence directions of the rays of light on the convex trajectory of the cloth.
The different incidence directions of the light in fact illuminate the cloth defects from different angles, making them stand out even when they are hardly visible if illuminated from one direction only.
Lighting can be at all events maintained satisfactory and high at all points by, for instance, resorting to the second light source placed under the cloth, flush with the reference plane, when the support and guide surface is made of glass, for example.
Every defect can be therefore easily detected.
The invention achieves important advantages.
Through simple means an important increase in the operability of the verifying machines has been achieved: exactly, the crucial operation of visually inspecting the cloth is now made easier and more efficient. This advantage is obtained without slowing down the cloth flow or enlarging the extension in height of the display device.

Claims

A verifying machine for cloth inspection, comprising a device (15) for displaying a cloth (4) to be inspected having a support and guide surface (16) for said cloth (4), characterised in that said support and guide surface (16) forms a loop bent outwardly of said verifying machine (1), to impose a convex trajectory to said cloth (4).
A verifying machine as claimed in claim 1, wherein said support and guide surface (16) for said cloth (4) to be inspected is fixed and has a convex shape.
A verifying machine as claimed in claim 1, wherein said support and guide surface (16) for said cloth (4) to be inspected is embodied by a roller projecting outwardly of said machine and movable together with said cloth (4).
A verifying machine as claimed in claim 1, wherein provision is made for at least one first light source (20) facing said control and guide surface (16) and defining differently lit regions at said convex trajectory of said cloth (4).
A verifying machine as claimed in claim 1, wherein said control and guide surface (16) extends between two end sections transverse to the movement direction of said cloth (4), wherein said end sections are embodied by an upper roller (17) and a lower roller (18), wherein said upper roller (17) and lower roller (18) are coplanar so as to define a reference plane (19), and wherein said convex trajectory has a portion of maximum projection from said reference plane (19) substantially located at the same distance from said upper roller (17) and lower roller (18).
A verifying machine as claimed in claim 5, wherein said convex trajectory is a portion of a cylindrical trajectory.
A verifying machine as claimed in claim 5, wherein provision is made for at least one first light source (20) facing said control and guide surface (16) and defining a region of maximum lighting at said portion of maximum projection of said convex trajectory.
A verifying machine as claimed in claim 7, wherein said control and guide surface (16) is at least partly transparent and wherein it is also provided at least one second light source (21), said first light source (20) and second light source (21) being disposed from opposite sides of said control and guide surface (16) and said second light source (21) being substantially disposed at said reference plane (19).