GB2204889A

GB2204889A - Folding textile materials

Info

Publication number: GB2204889A
Application number: GB08711285A
Authority: GB
Inventors: Robert Julien
Original assignee: Julien S A
Current assignee: Julien S A
Priority date: 1987-05-13
Filing date: 1987-05-13
Publication date: 1988-11-23
Also published as: GB8711285D0

Abstract

A folding machine for textile materials has an assembly consisting of a folding nose (20) for guiding the material and a compressed-air distributor (24) or rigid strip for urging it between a pair of calendering rollers (34, 36), this assembly being movably mounted so as to be able to assume a first position in which it delivers the textile material along a vertical path (B) near the rollers (34, 36), and a second position in which the textile material is delivered along a vertical path (A) distant from the rollers (34, 36). In this way accurate fold location may be achieved while enabling successive sheets of material to be fed at a higher frequency without fouling one another. Thus, whilst a first sheet, urged from position B, is taken up and folded by rollers 34, 36 a second sheet is already being delivered and guided by nose 20 along a path A spaced from path B. Predetermined sheet lengths along positions A and B respectively actuate displacement of the nose 20 to the first position and the urging of the sheet in the folding rollers 34, 36. <IMAGE>

Description

"FOLDING TEXTILE b'TERIALS." This invention relates to folding machines for textile materials and in particular to a device for feeding a folding station in such a machine.

The general layout of a relevant type of folding machine is shown diagrammatically in Figure 1.

In such folding machines the product to be folded is laid on conveyor belts 4 which move it over a fixed folding nose or angle which is positioned as near as practicable to a first pair of calendering rollers 34, 36. To urge the material when necessary between the rollers, a distributor for blowing compressed air is fixed behind the vertical path followed by the textile sheet after it leaves the conveyor belts 4, as near as possible to the path and to the first nipping or folding station formed by the two calendering rollers 34, 36 and conveyor belts 38, 40 that they carry.

At a predetermined stage in the movement of the textile sheet a known system comprising a photoelectric cell and a programmable automatic mechanism actuates the distributor to produce a line of compressed air jets which in a first step shift the hanging sheet to an adjacent parallel path tangential to the lower calendering roller 36 with which it then makes contact.

In a second step the sheet, folded at the predetermined location into two sections usually of unequal lengths, is fed through the first folding station.

The two conveyor belts on the calendering rollers then convey the folded sheet towards a second folding station 45, whence it proceeds by degrees through the other folding stations.

In conventional folding machines the distances which separate the compressed-air distributor, the moving textile sheet and the inlet of the first folding station must be kept as short as possible if the intention is to ensure accurate first folding, which is indispensable for obtaining a finished product of high quality.

In particular where multiple folding is involved, this accuracy is necessary for the following two main reasons: 1) Good transverse folding is possible only if the textile thicknesses have been distributed accurately during longitudinal folding. This means that the difference between the lengths of the two sections on either side of the first fold must be exactly as previously calculated, and that, furthermore, all the subsequent or virtually subsequent folds must be centered, so that the final product or "tube" has a shape as close as possible to a right-angled parallelepiped.

2) In the folding of e.g. bed sheets, it is usually preferred that the leading edge be on the outside, so that its finish (bourdon lace, hem, embroidered edge or patterns) is visible. For this purpose, the first fold is made rather towards the trailing edge which will consequently be concealed inside the tube during the subsequent folding operations.

For a given folding machine as described above, folding accuracy depends on two main factors: (1) the degree of slip of the sheet on the conveyors, and (2) the response time between the triggering of the photoelectric cell and the activation of the compressed-air blower as a function of the programmable automatic control. It should be emphasized that European machines presently have a scan time of the order of 100th of a second.

In conventional folding machines, the conveyor belts usually move at speeds of between 30 and 60 m/minute. It should be noted that the higher the speed, the greater the risk for given textile and belt types that the sheet will slip on the belt.

On the assumption that the slip is zero, the response time of the automatic control, that is to say 100th of a second, corresponds to a distance of between I cm for 60 m/minute and 0.5 cm for 30 m/minute.

Taking as a typical example a bed sheet with a length of 3.10 m, the leading edge of which projects 2.1 m beyond the folding nose at the moment when the compressed air jet is expelled, the sections on either side of the fold will have lengths of 2.10 m and 1 m.

The length of 2.10 m can subsequently be reduced, for example, to 1.20 m and 0.90 m, and the 1.20 m can finally be reduced by means of two folding operations to 0.60 m and 0.30 m. The tube obtained in this way will then be folded transversely, for example, to 0.40 m, in three successive folding operations.

Where successive sheets of material are concerned, the production capacity of conventional folding machines is limited in that they cannot be fed at the rate of change of which an attendance crew is likely to be capable.

This is because experience shows that the leading edge of a sheet can be laid on the conveyor belts of the feeder only if the first folding of the preceding sheet has virtually ended, so that it has passed almost completely through the calendering rollers of the first folding station to their two conveyor belts. In fact, in the conventional technique, the trailing edge of one sheet rising to the first folding station and the leading edge of the next sheet descending from the feeder follow very close parallel paths. This means that for large fabric widths the leading edge of the second sheet would risk coming in contact with the first sheet and being carried along by the latter as a result of friction if it has not yet been entirely taken up by the first folding station, especially if this edge or the fabric is relatively stiff.

In practice, the circumstances are even more unfavourable because the two parallel vertical paths are theoretical. In fact, they converge at floor level, at least at the start of the blowing operation, the hanging sheet resting on the floor at this moment.

It is therefpre all the more necessary for the folding of one sheet to have virtually ended before the next sheet is fed in.

As a result, for a sheet 3.10 m long folded into two sections of 2.40 m and 0.70 m, it is now necessary to wait until the rising section 2.40 m long is taken up completely before the following sheet is fed in. Thus the belt length necessary for the first folding is 3.10 m + 2.40 m = 5.50 m, and for a belt speed of 30 m/minutes this represents an overall folding time of 11 seconds.

Clearly it would be desirable to increase the potential productivity of folding machines by enabling them to be fed at a higher rate, perhaps even the maximum rate of which an attendance crew is capable.

For bed sheets this rate might correspond e.g. to a distance of 0.30 - 0.50 m on the conveyor between the trailing edge of one sheet and the leading edge of the next.

The vertical paths of the two successive sheets would have to be kept sufficiently far apart, during the period of feeding the second sheet and taking up the first, that the first does not carry the second along with it. If such a distance could be achieved the belt length necessary for folding a sheet might be reduced to 3.10 m + 0.40 m = 3.5C m, and for a belt speed of 30 m/minute this would mean a folding time of only 7 seconds, i.e. a potential increase in productivity of 36%.

However this proposed distance between the two vertical paths, making it possible to prevent the second sheet from being carried along by the first, is unfortunately incompatible with the requisite folding accuracy for two reasons. On the one hand, the compressed air jets would have to divert each sheet by a substantial distance from its descending path to the rollers, and therefore the response time would be long and the accuracy poor. Secondly, the air jet has itself to blow further and its dispersal near the inlet of the first folding station also tends to prevent accurate folding.

Some folding machines have rigid strips rather than compressed air distributors for urging the sheet, but it can be seen that in practical effect the above objections hold for these machines as well.

The invention proposes a guide assembly for the feed device that includes a folding nose and means (such as a compressed-air blower or rigid strip) for urging textile material to be folded towards the nip or gap of folding station rollers. The nose, and preferably the whole assembly, is mounted movably relative to the rollers so that in a first position the nose can guide the material from a conveyor to a path adjacent the rollers, while in a second position of the assembly the material is delivered along a path substantially spaced from the rollers. Preferably in this second position the guide assembly does not guide the material after it leaves the conveyor.

In this way the folding nose and urging means may be brought close to the rollers to give a fast response and accurate fold location, and yet enable the leading edge of a textile sheet to hang from the conveyor clear of the trailing part of a preceding sheet.

To make it easier to understand the invention, a practical exemplary embodiment of it will be described below, with reference to the accompanying drawings in which: Figure 1 is a diagrarrrnatic sectional elevation view of a folding machine for textile materials, making four longitudinal folds with the leading edge of a textile sheet being located on the outside of the folded product or tube and on the underside, this being the normal arrangement for folding sheets.

Figure 2 is a sectional elevation view, illustrating an embodiment of the invention, of the feeder of a folding machine, that is to say the part marked by I in Figure 1.

The folding machine (see Figure 2) is fed with fabrics to be folded by means of a conveyor belt 4 supported by a guide pulley 2. In general, this conveyor belt 4 is composed of a set of parallel belts.

A tube of rectangular cross-section 6, accommodated within two strands of the belt, supports, at each of its ends located on the outside, a bearing 8 with a horizontal pivot pin 9, about which pivots a connecting-rod end 7, inside which is screwed a threaded rod 10, the penetration of which is adjustable by means of the lock nut 15.

The other end of this threaded rod 10 passes through a component 12 which is perpendicular to it and to which it is fastened, on either side of the Latter, by leans of a bolt 13 waking it possible to adjust its positioning relative to the threaded rod 10.

This component 12 is welded to a plate 11 which is likewise perpendicular to it and which, at each end of the folding machine, supports a tube of square cross-section 14, extending over the entire width of the latter, by means of a rectangular notch, in which it is engaged and welded on three of its sides to the plate 11 and on one of its sides to the component 12.

This tube 14 supports a metal sheet 16 which guides the fabric sheet when the latter leaves the conveyor belt 4, of which the upstream part 18 is bent downwards slightly and the oval part 20 curved at 900 fores the folding nose or angle for the fabric sheet.

The supporting sheet 11 is perforated with a hole 22, to which is fastened a lug 23 supporting, on each side of the folding machine, a tube of square cross-section 24 which likewise extends over the entire width of the latter and which is connected to a compressed-air blower not shown in Figure 2. This tube 24, perforated on one of its faces with an entire series of s.all holes 25 through which the compressed air is ejected, forts the compressed-air distributor which will fold the sheet at the intended moment and the activation of which is commanded by a comaon-link device consisting of a photoelectric cell and of a programmable automatic control.

The supporting plate 11 is perforated with a second hole 26, to which is fastened a fork 28 screwed, at its other end, to the sliding rod 29 of a pneunatic cylinder 30 attached at a fixed point 32, the nut 31 making it pos sible to adjust the fork 28 relative to the sliding rod 29.

Tvo calendering rollers 34 and 36, each supporting a conveyor belt 38 and 40 rotating in opposite directions, carry the folded sheet along between then towards the second folding station not shown in Figure 2.

It emerges from the foregoing that the two suppor ting plates 11 and the components attached to it, namely the supporting tube 14, its guide sheet 16 and the com- pressed-air blower 24, can pivot about the horizontal pivot pin 9 via the connecting rod 7 and its threaded rod ;10 by means of the pneumatic cylinder 30 from a low posi tion represented by broken lines in Figure 3, in which the assembly as a whole is set back relative to the vertical (A) tangent to the guide pulley 2, and an advanced position, in which the vertical B is tangent to the folding nose 20.

When the leading edge of the fabric to be folded, which has been laid on the conveyor belt 4, leaves the latter, the supporting plate 11 is set back in the low position (represented by broken lines). At this moment, the sheet descends towards the floor along the vertical line A, to a predetermined level where, under the action of a knoun detection device (not shown), the supporting plate 11 and the components attached to it are brought into the advanced position (represented by unbroken lines? under the action of the pneuoatic cylinder 30 and thereby shift the path of the still moving fabric from the vertical A to the vertical B distinctly closer to the inlet of the first folding station consisting of the calendering rollers 34 and 36 and their conveyor belts 38 and 40.

Finally, when the sheet has moved on a further likewise predetermined length, another known device (not shown) consisting of a photoelectric cell and of a program mable automatic mechanism triggers the compressed-air blower 24 which, by means of the ejection holes or fittings 25, pushes the sheet forwards, over the entire width of the folding machine, up to the vertical C tangent to the lower calendering roller 36.

At this moment, under the twin action of the compressed-air jet and the two conveyor belts 38 and 40, the folded sheet is carried along between these and conveyed towards the second folding station.

Advantageously, to exhibit the leading edge of the sheet which is usually given a particular finish (bourdon lace, hem, embroidered edge, etc), and since this finish zust be visible on the outside, the first short fold must be made on the trailing edge which will subsequently be concealed by the successive folds.

This first fold is therefore usually obtained by allowing the leading edge of the fabric to hang down to a maximum length at the outlet of the feeder, until the point required for the short fold of the trailing edge is reached.

Once this sheet has been taken up between the two belts 38 and 40, the assembly comprising the folding nose 20 is returned to its retracted position (represented by broken lines).

Because the first short fold is aade near the trailing edge of the sheet, the latter comes away from the conveyor belt 4 quickly, whilst the much greater length of the front part of the sheet is raised along the vertical line C.

During the tine when the first sheet is raised, because the folding nose 20 is in a retracted position relative to'the vertical C, a second sheet can be delivered by the conveyor belt 4 even at this early stage, the leading edge of the sheet being allowed to hang down along the vertical Line A.

Claims

CLAIMS.

1. A machine for folding textile material or a device for feeding textile material to such a machine, comprising a feed conveyor for incoming material, a folding nose adapted to guide material coming from the conveyor, and means for urging a part of the material to be folded into a gap or nip between two rollers of a folding station, wherein the folding nose is mounted so as to be movable relative to the rollers between a first position for guiding material from the conveyor in a path passing adjacent the nip or gap between the rollers and a second position in which material from the conveyor is delivered along a path substantially spaced from the nip or gap.

2. A machine or device according to claim 1, wherein the nose and urging means are mounted on a corrmon mounting so as to be movable together.

3. A machine or device according to claim 1 or claim 2, wherein the folding nose and urging means are mounted pivotably so that they can be swung towards or away from the rollers.

4. A machine or device according to any one of the preceding claims wherein means for moving the folding nose between said positions are actuated in response to signals from a detector for detecting the position of the textile material.

5. A machine or device according to any one of the preceding claims wherein means for moving the folding nose and urging means between said positions comprise a piston and cylinder arrangement.

6. A machine device according to any one of the preceding claims wherein in the second position material from the conveyor is delivered along a path undeflected by the folding nose.

7. A machine device according to any one of the preceding claims wherein the urging means comprise a movable rigid strip or means for blowing compressed air at the material.

8. A machine or device according to any one of the preceding claims wherein the conveyor, folding nose and urging means are mounted such that in said first position material passing over the folding nose can hang substantially vertically therefrom while in said second position material passing from the conveyor can hang substantially vertically from the conveyor.

9. A machine for folding textile material, comprising a set of feed conveyor belts supported by a guide pulley, a guide sheet forming a folding nose and a compressed-air distributor or rigid strip intended for feeding the textile material between two calendering rollers and their conveyor belts of a folding station, characterized in that the assembly consisting of the folding nose and of the compressed-air distributor or rigid strip is movably mounted so that the assembly can assume at least two positions, namely a first position in which it can deliver the textile material along a first substantially vertical path near the two calendering rollers and a second position in which the textile material can be delivered along a second substantially vertical path set apart from the two calendering rollers.

10. A machine according to claim 9 wherein in the second position the assembly consisting of the nose and of the distributor is set back completely from the vertical path followed by the textile material delivered by the conveyor belt.

11. A machine according to claim 9 or 10 wherein the assembly consisting of the nose and of the distributor pivots about a pivot pin under the effect of a control cylinder.

12. A process for folding textile material, wherein a first piece of material to be folded is guided from a conveyor along a path adjacent folding means of a folding station, a part of the material is urged into the folding station so as to be taken up and folded thereby, and during the take-up of the first piece of material a second piece of material for folding by the folding station is already being delivered from the conveyor along a substantially vertical path spaced from the folding station.

13. Process for feeding textile material to a folding machine comprising several folding stations, characterized in that a first piece of textile material is first brought near to a folding station and urged so as to be taken up by the latter at a predetermined time by means of a rigid strip or the expulsion of compressed air, in order to make a first fold, and in that, during the take-up of the first piece of material by this folding station, a second piece of textile material is already being delivered along a vertical path set apart from the first folding station.

14. A process according to claim 12 or claim 13, wherein the first fold is obtained by allowing the leading edge of the first piece of textile material to hang down to a rnaximum length at the outlet of a conveyor until an intended point for making a fold towards the trailing edge of the piece is reached, at which time the material is urged against driving belts of the folding station by means of a movable strip or by the expulsion of compressed air and is taken up between the belts.

15. A process according to claim 14, wherein when the first piece of textile material has been received completely by the folding station, a second piece of textile material is guided to a path adjacent the folding station so that it can be urged into it.

16. A machine for folding textile material, or feeding device therefor, substantially as herein described, with reference'to and as illustrated in Fig. 2 of the drawings.

17. A folding process substantially as herein described with reference to Fig. 2 of the drawings.