METHOD FOR MAKING A PLEAT CURTAIN AND DEVICE SUITABLE THEREFOR

The present invention relates to a method for making a pleat curtain with a predetermined number of pleats having a predetermined pleat depth with a predetermined spacing between them, comprising at least two curtain panels being joined at joining edges. The invention further relates to a device for making such curtains.

Such a method and device are generally known.

To make a curtain look more attractive, pleats are generally formed in the curtain material, which pleats ensure that the curtain will drape nicely when drawn. Depending on the type of pleat, a larger unpleated length of curtain material is needed for making a curtain having a particular pleated length, i.e. the length the curtain will cover in the drawn position, since said pleats require extra material. It will be apparent that more material is required for a curtain comprising more complex pleats, for example double pleats, also called butterfly pleats, or triple pleats, than for a curtain of the same pleated length comprising single pleats. The amount of material needed for creating a pleat is usually called the pleat length.

Depending on the type of pleat, a pleat is formed in a curtain by folding an amount of curtain material "double and joining the folds together in the form of a loop at least at the upper side of the curtain, for example by stitching. Since the pleat is usually only stitched at the upper side, as already noted before, the lower part of the curtain will flare out, so that a nice drape of the curtain is obtained.

When making a curtain there are a number of other relevant parameters besides the type of pleat that determine the appearance of a curtain. In addition to the type of material and the length of the curtain in pleated condition, also the pleat spacing and the pleat depth are relevant. The pleat spacing determines the distance between the pleats in the curtain, and the pleat depth determines the length of the pleat perpendicular to the plane of the curtain. It will be understood that from these data follows the number of pleats in a curtain, although it is also possible, as those skilled in the art will appreciate, that first the number of pleats is determined and that the pleat spacing will be determined on the basis of the length of the curtain.

Since the length of curtain material is not unlimited, several lengths of curtain material, also called curtain panels, are generally joined together when larger curtains are to be made. Said curtain panels need not have the same length, since it may be advantageous to incorporate remaining material from another curtain in the curtain.

Moreover, the curtain panels are usually provided with hems at the edges of the curtain, so that in any case the outer curtain panels of a curtain will have different lengths.

It is an object of the present invention to provide an efficient, flexible and/or simple method for making a pleat curtain, preferably by means of a mechanized process, which leads to an embellished appearance of the curtain.

In order to accomplish that object, the method of the kind referred to in the introduction is characterised in that the pleat depth is corrected for each curtain panel, such that the joining edges comprise substantially whole pleats or

pleat spacing segments, whilst the pleat spacing remains substantially the same across the curtain. Thus, a method for making a pleat curtain is provided wherein each curtain panel comprises whole pleats and pleat spacing segments and wherein the curtain panel does not comprise an incomplete pleat or pleat spacing segment at the beginning or the end of the curtain panel.

In other words, the pleat depths and thus the pleat lengths of the pleats in the individual curtain panels are corrected so that no material will remain after the last pleat or pleat spacing segment has been formed in a curtain panel. By modifying the pleat depths of the pleats in a curtain panel, the amount of material required for a single pleat can be adapted so that it is possible to form a whole number of pleats and pleat spacing segments in a curtain panel. As a result, each joint between two curtain panels extends substantially adjacent to a pleat, since each curtain panel begins and ends either with a whole pleat or a with a whole pleat spacing segment .

This intelligent pleat calculation has the advantage that the joint between two curtain panels, which might be perceived as an objectionable interruption in the image of the curtain, falls between two pleats and is thus hidden from view behind the pleat, at least at the upper side of the curtain, where said pleats have been formed, for example by stitching. It will be understood that this makes the curtain look better than curtains made by using the known method, where the location of the seams between curtain panels depends on the length of the curtain panel. Thus, a seam may fall halfway between two pleats in the pleat spacing segment, in which case the seam will be quite

noticeable, or in a pleat, in which case the appearance of the pleat will change as a result of the presence of the joint at that location.

In a preferred embodiment of the method according to the invention for making a pleat curtain, said correction of the pleat depth comprises determining a pleat section configuration, which pleat section comprises the length of material required for a pleat, or a pleat length, and a pleat spacing section, as well as determining a remaining fabric portion, which remaining fabric portion comprises the length of material that remains after the last whole pleat section in a curtain panel. Preferably, the process of determining the remaining fabric portion comprises determining the number of whole pleat sections in a curtain panel. In other words, the pleat section comprises a single pleat length and the associated pleat spacing segment after said pleat, whilst a curtain panel comprises several pleat sections:

j, , . Length curtain panel

# pleat _sec ttons — ² —= ==- pleat _sec tion

The material that remains, the remaining fabric portion, if a maximum number of whole pleat sections would be formed in a curtain panel is determined on the basis of the length of the curtain panel and the length of the pleat section:

remaining _ fabric _ portion =

Length _curtain _ panel -(if pleat _ sec tions x pleat _ sec tion)

Since a curtain panel must end with a substantially whole pleat or a whole pleat spacing segment, said remaining fabric portion is a measure for correcting the pleat depth, with the remaining fabric portion being distributed, as it were, over a number of pleats in a curtain panel. It will be understood that the remaining fabric portion will at all times be smaller than the pleat section.

The term pleats, pleat spacing segments or pleat sections as used in this context is to be understood to mean that the whole element, pleat or pleat spacing segment is comprised in the curtain panel, and that no partial elements are formed, therefore, because insufficient fabric remains for forming such an element .

In another preferred embodiment of the method according to the invention for manufacturing a pleat curtain, said correction of the pleat depth comprises determining the correction depth for each pleat, which correction depth is proportional to the number of pleats in the curtain panel and the remaining fabric portion of the curtain panel. The remaining fabric portion for which a correction is to be made is distributed over all the pleats in a curtain panel, as it were, so that the individual pleats are minimally corrected, which benefits the appearance of the curtain. The process of determining the aforesaid correction depth will be discussed in more detail yet hereinafter.

In another preferred embodiment of the method according to the invention for making a pleat curtain, said correction of the pleat depth comprises increasing the pleat depth in a curtain panel when the remaining fabric portion falls within a first half of the pleat length or the pleat spacing

segment of the pleat section, and said correction comprises decreasing the pleat depth in a curtain panel when the remaining fabric portion falls within a second half of the pleat length or the pleat spacing segment of the pleat section. As a result of such a correction, the joint with the next curtain panel is shifted to a location either before or after the next pleat or pleat spacing segment, depending on which shift requires less correction.

If it should be found that the seam would fall within a first half of a pleat, it will be advantageous to increase the pleat depth and thus the pleat length of the pleats in the curtain panel such that the amount fabric required for a pleat section is increased, so that the joint will be located practically just before the pleat. The curtain panel thus obtained will end with a whole pleat spacing segment in that case, and the next curtain panel will begin with a pleat- If it should be found that the joint would fall within the first half of a pleat section segment, the pleat depths of the pleats in the panel will be increased so that the joint will be located practically just after the last pleat. The curtain panel will end with a pleat in that case, so that the next curtain panel will have to begin with a pleat spacing segment. In a corresponding manner, the pleat depths will be decreased if it should be found that the seams would fall within the second half of the pleat length or the pleat spacing segment.

Modifying the pleat depths in a curtain panel makes it possible to shift the location of the end of a curtain panel, where said curtain panel is to be joined to another panel. This makes it possible to realise joints located practically just before and just after the pleats. It will

be understood by those skilled in the art that a curtain thus obtained comprises curtain panels with mutually different pleat depths. In view of the relatively large number of pleats per curtain panel in relation to the remaining fabric portion to be corrected, maximally half a pleat spacing or pleat length, such a different pleat depth will be hardly noticeable.

In another preferred embodiment of the method according to the invention for making a pleat curtain, said joining together of the curtain panels comprises sewing together the curtain panels, wherein said at least one seam extends substantially adjacent to a pleat.

In another preferred embodiment of the method according to the invention for making a pleat curtain, a margin is provided between a seam and a pleat . Preferably, said margin is smaller than 20 mm, more preferably smaller than 10 mm, even more preferably about 5 mm. Not having a pleat and a joining edge coincide exactly has certain advantages as regards the strength of the joint. Usually, connecting hooks for hanging the curtain are attached to the curtain at the location of the pleat, for example by sticking pins through the curtain material. Said piercing at the location of a seam may affect the strength of a connection. This problem is solved by using a margin between the pleat and the seam.

Such a margin must be taken into account when correcting the pleat depth for the purpose of shifting the seam in the last pleat section. Six cases can be distinguished in this regard, depending on the location where the seam would fall within the pleat section without such a correction, that is:

where the end of the remaining fabric portion would fall within the pleat section.

When it has been determined that the seam falls within the pleat, the remaining fabric portion is compared with half the pleat length. If it is found that the remaining fabric portion is smaller than half the pleat length, the seam will be located in the first half of the pleat, being the first case. From this it follows, as already discussed before, that the shortest shift of the seam is a shift to a location before the pleat. That is, the next pleat section is not taken to form part of this panel. The seam is corrected in forward direction, as it were, and this is done by making the pleats in the panel in question deeper, which means that the pleat length will be longer/greater. The extent of the shift is the remaining distance. The seam is located before the pleat, so that the margin is added as an additional shift :

shift = remaining _ fabric _ portion + margin

In this case, the number of pleats for which a correction is going to be made is the number of pleat sections in the curtain panel, since the last pleat section will end with a pleat spacing segment:

#correction_pleats =#pleat_sections

This can be used for calculating the new pleat length:

New_ pleat _ length = pleat _length J- shift

I # correction _ pleats

It should be noted that the last term in the above equation corresponds to the correction depth for each pleat. It is necessary in this regard to take into account the number of pleats in the curtain panel.

In the second case, however, it is concluded that the remaining fabric portion is greater than half the pleat length, and in that case the seam is located in the rear part of the pleat. The seam is corrected in rearward direction, therefore. This is done by making the pleats in the curtain panel less deep, the pleat length will be shorter/smaller. The amount of material being shifted comprises the pleat length minus the remaining fabric portion. The seam is now located behind the pleat, although shifting is also done in the other direction. This implies that the margin must still be added as an extra shift:

shift = (pleat _ length - remaing _ fabric _ portion) + m arg in

In this case the pleat section does fall within the panel in question, so that it must be taken into account in the correction. The curtain panel ends with a pleat in this case:

# correction _ pleats =# pleat _ sec tions + 1

On the basis of this, a new pleat length can be calculated again:

( shift )

New _ pleat _ length - pleat _ length —

\ # correction _ pleats _j

If it is concluded that the seam does not fall within the pleats but within the pleat spacing segment, a different correction will be used. First it is determined whether the position within the pleat spacing segment falls within the margin. To that end, the remaining fabric portion-pleat length is compared to the margin. If said distance is smaller than the margin, the seam will fall between the next pleat and the margin, being the third case.

This means that the seam is corrected in rearward direction, so that it will fall behind the next pleat on the margin. The amount of material being shift is the margin minus the remaining fabric portion-pleat length. The margin is included:

shift = m arg in — (remaing _ fabric _ portion — pleat _ length)

# correction _ pleats =# pleat _ sec tions + 1

New _ pleat _ length = pleat _ length - ( shift λ

\ # correction _ pleats _j

When it has been determined that the seam does not fall within the pleat but within the pleat spacing segment, it is subsequently determined whether the position within the pleat spacing segment falls within the rear margin, which would be the fourth case. To that end, the remaining fabric portion-pleat length is compared with the pleat spacing- margin. If this first distance is larger, the seam will fall within the margin for the pleat of the next pleat section, which implies that it will be located two pleats further.

This means that the seam is corrected in forward direction, so that it will fall within the margin for the aforesaid pleat. The amount of material being shifted is the remaining fabric portion-pleat length minus the pleat spacing-margin. The margin is included:

Verplaatsing = (remaing _ fabric _ portion - pleat _ length) - (pleat _ spacing - margin)

# correction _ pleats =# pleat _ sec tions + 1

New _ pleat _ length — pleat _ length • ( shift ϊ

\ # correction _ pleats _J

If it is concluded that the seam does not fall within the pleat but within the pleat spacing segment, and said seam does not fall within the margins, a different correction is used. First, the position within the pleat spacing segment is determined by deducting the pleat length from the remaining fabric portion. This position is compared with half the pleat spacing. If the result of the equation

"remaining fabric portion minus pleat length" is smaller than half the pleat spacing, the seam falls in the front half of the pleat spacing segment, being the fifth case. This means that the seam is corrected in forward direction, so that it will fall behind the next pleat. The amount of material being shifted equals the result of the equation "remaining fabric portion minus pleat length". Since the margin is now negative in relation to the shift, it is deducted therefrom:

shift = remaing _ fabric _ portion - (pleat _ spacing + margin)

The next pleat falls within the panel, since the seam is located behind the next pleat:

# correction _ pleats =# pleat _ sec tions ^■ + 1

If the result of the equation "remaining fabric portion minus pleat length" is greater than half the pleat spacing, the seam will fall within the second half of the pleat spacing segment, being the sixth case. This means that the seam is corrected in rearward direction, so that it will fall before the pleat of the next pleat section, which implies two pleats further. The amount of material being shifted is the pleat spacing minus the result of the equation "remaining fabric portion minus pleat length", that is, the position within pleat spacing segment. The margin is still negative in relation to the shift, so it is deducted therefrom:

shift = (pleat _ spacing) - (remaing _ fabric _ portion - pleat _ length)) - margin

The next pleat falls within the panel, since the seam is located behind the next pleat:

# correction _ pleats =# pleat _ sec tions + 1

( shift )

New _ pleat length = pleat _ length -

{ # correction _ pleats _t

In another preferred embodiment of the method according to the invention for making a pleat curtain, said correction of the pleat depth comprises determining the total number of pleats already formed and the length of the total number of remaining, yet unpleated curtain panels. Once the new pleat length for a curtain panel has been determined, the new pleat section configuration is determined on the basis of said correction depth. Starting from this new pleat section configuration, the amount of fabric used for the panel in question, in this example panel 1, is determined:

material _ used _ panel _ 1 = new _ pleat _ lengthxU correction _ pleats

Then the remaining fabric portion is calculated for the next panels on the basis of the length of the curtain in unpleated condition and the already pleated material of the completed panels in accordance with the general calculation represented below, in which x is the panel in question:

remaining _ material _ panel _x = curtain _ unpleated — (material _ used _ panels < x + length _ panels > x)

For determining the remaining material in a third curtain panel of a total of four panels having a specific length, for example, the following equation applies:

remaining _ material _ panel _x = curtain _ unpleated — (material _ used _ panel _1 + material _ used _ panel 2 + Length _panel_4)

On the basis of this remaining fabric portion result, a new pleat depth can be determined for the rest of the curtain, starting from the pleat spacing segments and the pleats yet

to be made in the remaining panels, which are determined on the basis of the correction pleats already made:

New_ pleat _length after _panel_X =

(curtain _ unpleated — (panels _ used < X)) — (pleat _ spacing _ sections _to_be_ made *pleat_ length) pleats _ yet _to_be _ made Using this new pleat length, a new pleat section can be determined, whereupon the correction for the next panel can be started again by determining the remaining distance as described above. This procedure will be repeated for all the curtain panels, so that a curtain is provided in which all the seams between curtain panels will fall before or after the pleats with a certain margin.

It should be noted that the above method is preferably carried out by machine.

The invention further relates to a method for making a pleat curtain with a predetermined number of pleats having a predetermined pleat depth with a predetermined spacing between them, comprising at least two curtain panels being joined at joining edges, wherein the pleat depth is corrected for each curtain panel, such that the joining edges extend at a predetermined location in the pleat spacing segment, whilst the pleat spacing remains substantially unchanged across the curtain. In a similar manner as described above, a curtain can be made in which the seams between the various curtain panels extend at predetermined locations in the pleat section. Such a method can for example be carried out by modifying the above- described margins in such a manner that the seams will fall exactly between two pleats.

The invention further relates to a device for making a pleat curtain with a predetermined number of pleats having a predetermined pleat depth with a predetermined spacing between them, comprising at least two curtain panels being joined at joining edges, wherein the device comprises engaging means for engaging the curtain panels for forming pleats therein, transport means for transporting the curtain panels, joining means for joining the curtain panels together, and at least one control device for controlling the engaging means, the joining means and the transport means, wherein said control device is arranged for correcting the pleat depth for each curtain panel such that the joining edges comprise substantially whole pleats or pleat spacing segments, whilst the pleat spacing remains practically unchanged across the curtain.

The invention will now be explained in more detail by means of a calculation example, in which the following input variables are used for the curtain to be made: GG - the length of the curtain in pleated condition; GO - the length of het curtain in unpleated condition; and PAV - the preferred pleat spacing, whilst furthermore a triple pleat is used:

GG = 2000 mm GO = 5250 mm PAV = 80 mm

In addition, the number of curtain panels AB and the lengths of each of the curtain panels B_x are determined, whilst furthermore the margin S is stated:

AB = 4

B_l = 1300 mm B_2 = 1500 mm B_3 = 1450 mm B_4 = 1000 mm S = 5mm

On the basis of this, the number of pleat spacing segments APA, the number of pleats AP, the total amount of material required for all pleats TSP, the pleat length PL, the pleat section configuration PB and the pleat depth PD can be calculated:

APA = 25 AP = 26 TSP = 3250 mm PL = 125 mm PD = 25.5 mm PB = PL+PA= 125mm + 80 mm = 205 mm

Subsequently, the first curtain panel will be corrected by determining the number of pleat sections in the panel APB and the remaining fabric portion STN:

.__ B 1 1300 _£ _. _c

APB =—=-= =6.34...« 6

PB 205 S7W = S_l-(.4P5xP5) = 1300-(6x205) = 1300-1230 = 70mm

De remaining length STN of 70mm is smaller than the pleat length, so that the seam falls within the pleat. In the next case, case number 2 as described above, the remaining length is 70mm larger than half the pleat length, so that it will be located in the rear part of the pleat. The seam will thus be shifted towards the rear in shift VN:

VN = (PL - STN) + m arg in - (125mm - 70mm) + 5mm = 60mm

Following that , the number of correction pleats ACP and the total number of correction pleats TCP are determined:

ACP = APB + l = 6 + l = 7

TCP = TCP + ACP = 0 + 7 = 7

These parameters are used for determining the corrected pleat length of the first curtain panel CPL_B_1 en het corrected pleat section configuration CPB:

CPB = CPL _B_\ + PA = \ \ 6A3mm + 80mm = 196.43mm

From this follows the used unpleated material of panel 1 VB_1 :

VB _\ = CPBx ACP = 196.43mmx 7 = 1375mm

These data can be used for calculating how much material will remain up to the next seam, the length of panel 2 after correction CB_2 :

C5_2 = GO-(rø_l + 5_3 + 5_4) = 5250ιnm-(1375 + 1450mm + 1000mm) = 1425mm

Following that, work on panel 2 is started, and the old PL and PB are overwritten, since they are no longer used . From this follows the new configuration for panel 2 :

(CB Jl + B_3 + B_4)-(PAx (APA - TCP))

AP-TCP

((1425mm + 1450mm + 1000mm)- (80mm x (25 -7)) 26-7

(3825mm -1440mm)

= - -=128.16mm

19

PB = PL+PA =128.16mm+80mm = 208.16mm

Starting from the pleat section configuration, the position of the next seam is determined again:

STN = CB _2 - (APBx. PB) = 1425mm- (6x 208.16mm) = 1425mm - 1448.96mm = 176.04mm

From this it follows that this is case 6 as described before, which means that the seam must be shifted backwards, just before the pleat after the next pleat:

VN= (PA-(STN-PL))S = (80mm-(176.04mm-128.16mm))-5mm = 27.12mm

Analogously to the situation described for the first panel, the pleat section configuration is modified and the amount of material used is determined:

ACP = APB + 1 = 6+1 = 7

TCP= TCP+ACP = 7+7 =14

CPL B 2 = PI- -f^^l == 1 i2z8o..1i6ommmm-—f i ^^^1 = 128.16/n/w-3.87mm = 124.29/π/π

\ACP) { 7 J

CPB = CPL_B_2 + PA = 124.29mm + 80mm = 204.29mm

VBJl = CPB x ACP = 204.29mmx 7 = 1430mm

Based on this information, we can calculate how much material will remain up to the next seam, the length of panel 3 after correction CB_3 :

CB_3 = GO-(VB_\ + VB_2 + B_4) = 5250mm-(1375 + 1430mm + 1000mm) = 1445mm

Then the correction of panel 3 is started, with the old PL and PB being overwritten, since they are no longer used. From this follows also the new configuration for panel 3 :

r _L _ (CB _3 + B _4)-(PAχ(APA-TCP))

AP-TCP _ ((1445mm + 1000mm)-(80mmχ(25-14))

26-14 (2445mm -880mm)

= 130.42mm

12

PB = CPL + PA = I 30,42mm + 80mm = 210,42mm

PB 210,42

STN = CB_3-(APBχ PB) = 1445mm - (6 x 210,42mm) = 1445mm - 1262,52mm = 182,48mm

Also this case appears to be a case 6 :

VN = (PA- (STN - PL)) -S = (80mm - (182.48mm - 130.42mm)) - 5mm = 22.94mm

ACP = APB + ] = 6 + 1 = 7

TCP = TCP + ACP = 14 + 7 = 21

CPL _B J, = PL -f-~-l = 127.14mm

CPB = CPL _ B_3 + PA = ffl.Umm + 80mm = 207.14mm

VBJh = CPBx ACP = 207.14mmχ7 = 1450mm

Using these data, it can be calculated how much material will remain up to the next seam, the length of panel 4 after correction CB_4 :

Cβ_4 = GO-(rø_l + rø_2 + KB_3) = 5250mm- (1375 + 1430mm+1450mm) = 995mm

In a corresponding manner, the pleat depth in panel 4 is corrected, which may involve overwriting the old PL and PB. From this also follows the new configuration for the next panel :

CB _4 - (PAx (APA - TCP))

AP -TCP

^ 995 -(80mm x (25 -21)) 26- 21

(995mm -320mm) , , . = i 1 — 135mm

PB = CPL + PA = 135mm + 80mm = 215mm

" ^{■ =} 1

For the last panel it holds that the number of pleat sections APB x the pleat section configuration PB + 1 pleat, for finishing, must equal the corrected length of panel 4 CB_4:

CB_4 = (APBχ PB) + (IxCPL) = (4x215mm) + (lx 135mm) = 860mm +135mm = 995mm

VB_4 = CPBχACP +(lxCPL) = 2l5mmx4+ 1x135 = 995mm

Upon verification, this appears to be correct:

VB_4=CB_4=995mm=995mm

Also the total length of the curtain in unpleated condition GO appears to correspond to the lengths of material used of each of the panels:

GO = VB_l+ VB_2 + VB_3+VB_4 = 5250mm

— 1375mm +1430mm + 1450mm + 995mm

The invention will be explained in more detail hereinafter with reference to figures of a drawing, in which:

Figure 1 is a schematic front view of a curtain made according to the known method;

Figure 2 shows in top plan view the pleat depth, the pleat length, the pleat spacing and the pleat section configuration in a curtain;

Figure 3 shows in top plan view the determination of the remaining distance in a curtain according to the invention;

Figure 4 shows the position of the seam of a curtain panel in a pleat according to figure 3;

Figure 5 schematically shows the correction scheme according to the invention; and

Figure 6 is a top plan view of three curtain panels of a curtain made according to the invention.

In figure 1 a curtain 1 of the known type is shown. For decorative purposes, the curtain 1 is provided with evenly spaced pleats 2, which even spacing comprises the pleat spacing segment PA. Especially if the curtain 1 is a long curtain, a curtain 1 comprises several curtain panels Ia, Ib, Ic. The curtain panels Ia, Ib, Ic are joined via seams 3. As figure 1 shows, the seams fall within the pleat spacing segment PA between the pleats 2. Such visible seams 3 are usually found to be unsightly. As already mentioned before, it is an object of the present invention to provide a solution to this problem.

Figure 2 shows a part of the curtain 1 with a single pleat 2. The pleat 2 has a pleat depth PD, which determines the distance between the outermost point of the pleat 2 and the curtain 1. After a pleat 2 follows a pleat spacing segment PA, as shown. The pleat 2 is formed by folding a length of

material required for the pleat 2, the pleat _. , length PL, also shown in extended form in figure 2, double according to a specific shape and connecting it with a seam 4 in the plane of the curtain 1. The pleat length PL is thus the amount of curtain material required for forming a pleat 2 having a pleat PD. The pleat length PL and the pleat spacing PA jointly form a pleat section configuration PB. The pleat section configuration PB is thus the amount of material required for forming a single pleat 2 and a pleat spacing segment PA. It will be apparent to those skilled in the art that the pleat length PL is determined by the type of pleat and the desired pleat depth PD. It will be understood that a more complex pleat having the same pleat depth, for example a triple pleat, has a greater pleat length PL than a more simple type of pleat. As a result, the pleat section configuration PB will likewise vary.

Usually, a customer will indicate a desired pleat depth PD, the pleat spacing PA and the type of pleat. Depending on the length of the curtain 1, the number of pleats in the curtain will follow therefrom. Normally, the pleats 2 and the pleat spacing segment PA therebetween will then be formed in a curtain panel, eventually reaching the end of the curtain panel .

This situation is schematically shown in figure 3, in which a last pleat section PB (not shown) comprising a folded PL ¹ as shown and a pleat spacing segment PA has been formed in a curtain panel Ia. As shown, insufficient material remains up to an end 5 of the curtain panel Ia for incorporating another pleat section PB in the curtain panel Ia. The remaining fabric portion STN, or, in other words, the amount of material up to the seam, is even smaller than the pleat

length PL in figure 3, so that the seam 3 formed upon joining the curtain panel to next curtain panel Ib, as shown in figure 4, would fall in the middle of the pleat 2, resulting in a poorly shaped pleat. Another possibility would be for the amount of remaining material STN to suffice for forming a new pleat 2 if the amount of remaining material STN is larger than the pleat length PL, so that the seam 3 will fall within the pleat spacing segment PA of the next pleat section. This is the case in two instances with the seams 3 in the curtain 1 as shown in figure 1.

It is the object of the invention to avoid the above situations in the curtain by arranging for the seams 3 in a curtain to fall just before or just after a pleat 2, so that the seams 3 will be hidden from view behind the pleats, at least at the upper side of the curtain 1. To that end a correction system has been developed, which ensures that the seams will fall just before or just after the pleats by modifying the pleat depth PD or the pleat length PL in a pleat section PD. Such a variation of the pleat depth PD is hardly noticeable once the curtain hangs, because a curtain panel comprises several pleats.

To minimise the difference in depth in the pleats, the correction depth is kept as small as possible. This is done by correcting in the direction of the nearest location before or after a plate. As already noted before, the seam between two curtain panels is formed at a small distance from the pleat, so as not to weaken the seam, for example as a result of a hook being fixed in the seam.

Figure 5 schematically shows the correction scheme according to the invention. Figure 5 shows the pleat length PL and the

pleat spacing PA of the pleat section PB in unpleated form. The figure also indicates the margins S, wherein the seams, after correction, will be located at a distance S before the pleat length PL at location 11, after the pleat length PL at location 12 and before the next pleat of the next pleat section, in the last part of the pleat spacing segment PA, at location 13.

Depending on the length of the remaining fabric portion STN, as shown in figure 3, the pleat depth in the curtain panel will be corrected with reference to figure 5. Important in that regard is the question in which zone of the pleat section PB the end of the remaining fabric portion STN falls. The shifting of the seam according to the invention for the various zones is indicated by the arrows. Six cases can be distinguished in this regard, which cases are indicated by Roman numerals I - VI in the figure. These numerals correspond to the previously discussed cases with the associated correction calculations.

If the remaining fabric portion STN is shorter or, in other words, smaller than half the pleat length PL, as indicated by reference numeral 6 in the figure, the seam will be shifted towards location 11, at a distance S from the beginning of the pleat. This zone in the pleat section PB is indicated by numeral I in the figure, and corresponds with case number one as discussed before. To achieve this correction, the pleats in the curtain will have to be made deeper, so that the seam will fall at location 11 upon forming the pleats with the corrected pleat section configuration, depending on the length of the remaining fabric portion STN. A curtain panel corrected in this way will end with a pleat spacing segment PA, namely the pleat

spacing segment of the preceding pleat section PB (not shown) , since the pleat section is removed as a result of the correction, as is shown in figure 5.

In case of a remaining fabric portion STN being smaller than the pleat length PL but larger than half (6) the pleat length, indicated as zone II, the seam will be corrected towards location 12, at a distance S after the pleat. To that end, the pleats in the curtain are made less deep, as discussed with reference to case number two. In this way the curtain panel will end with a pleat, and the next panel will have to begin with a pleat spacing segment PA, as otherwise two pleats with little space between them would be formed in the curtain. It should be noted that figure 3 appears to indicate a case number three, since the remaining fabric portion STN seems to be larger than half the pleat length PL.

If the remaining fabric portion STN would fall within the pleat spacing segment PA, i.e. the remaining fabric portion STN is larger than the pleat length PL, but still within the margin S after the pleat, this would indicate a case number three, indicated at III. In this case the pleat depth in the curtain panel will be reduced to such an extent that the seam will fall exactly at location 12. Similarly to case number two, indicated at II, the curtain panel will now end with a pleat. A remaining fabric portion STN falling within the last margin S of the pleat section PA, indicated at IV or case number four, will be corrected to a location 13 by making the pleats deeper. The curtain panel will end with the pleat spacing segment PA in this case.

In a corresponding manner as discussed for the situation in which the remaining fabric portion STN would fall within the pleat length PL, the pleat section configuration PB in the curtain panel will be corrected by modifying the pleat depth if the remaining fabric portion STN falls within the pleat spacing segment PA, with this understanding that the margins S are now relatively different in comparison with the location from which a correction is to be made.

If the remaining fabric portion STN now falls within the zone V, i.e. being larger than the pleat length PL plus the margin S and smaller than half (7) the pleat spacing PA, the seam will be directed towards location 12 by making the pleats deeper, thus enlarging the pleat sections in the curtain. The curtain panel ends with a pleat in this case.

In the sixth case, if the length of the remaining fabric portion STN falls within the zone VI in the pleat section PB, the seam will be shifted towards location 13 by making the pleats less deep, depending on the remaining fabric portion STN, as in all cases. Similarly to case number four, the curtain panel will end with a whole pleat section PB with a pleat spacing segment PA.

It will be apparent to those skilled in the art that it is preferable to correct towards the nearest seam location 11, 12 or 13, depending on the remaining fabric portion STN, so as to minimise the differences in depth in the curtain. As also noted in the foregoing, the "additional" pleat sections being formed in the curtain panel by the correction should be taken into account as well. In cases IV and VI, a whole pleat section PB has been formed in the curtain all the same, although originally insufficient material was

available for this- Moreover, in cases II, III and V an additional pleat is formed in the curtain panel, with the curtain panel ending with the pleat in question, therefore. Next curtain panel will have to begin with a pleat spacing segment PA, therefore. The "additional" pleats formed within the framework of the correction, in all the cases except case number I, are also included in the correction process, in other words, as correction pleats they will be given a modified pleat depth.

Figure 6 shows a curtain 1 according to the invention consisting of three curtain panels Ia, Ib and Ic. The curtain panels will be joined by seems 3. As the figure shows, the three curtain panels have different pleat depths PD ¹ , PD ^{1 1} and PD ^{1 1 1} . Although the effect thereof is exaggerated in the figure, the difference in pleat depths across a curtain will be hardly noticeable. Thus, the greatest difference in pleat depth in the curtain of the calculation example is 3.78 mm.

It will be understood that said depths depend on the correction method which is used, as described above, depending on the remaining fabric portion STN of each of the panels. As shown, curtain panel Ia ends with a pleat spacing segment PA, and a correction according to cases I, IV or VI may have been made. Curtain panel Ib therefore begins with a pleat 2, preceded by the margin S. Curtain panel Ib ends with a pleat 2 with the associated margin S. Case II, III or V may have applied in this case. Curtain panel Ic begins with a pleat spacing segment PA in that case and will automatically end with ^" a pleat spacing segment PA, since a correction is not necessary in the last curtain panel Ic as a result of the correction and the determination of the

remaining fabric portion in the curtain and the modification of the pleat section configuration.

The invention is not limited to the embodiment discussed herein, but it also extends to other preferred variants falling within the scope of the appended claims . Thus it will be possible, for example, to make corrections only to such an extent that a curtain panel will only ends with a pleat section segment or to gradually modify the pleat depth in a curtain panel so that two adjacent pleats of two different curtain panels will have substantially the same pleat depth.

ABBREVIATIONS

PD = Pleat Depth

TSP = Total Material Pleats (total length of material required for all pleats)

PL = Pleat Length (length of material required for 1 pleat)

PA = Pleat Spacing Segment

APA = Number of Pleat Spacing Segments

PAV = Pleat Spacing Segment Preference (fixed parameter to be set)

GG = Curtain Pleated

GO = Curtain ϋnpleated

AP = Number of Pleats

PB = Pleat Section APB - Number of Pleat Sections

STN = Material to Seam or remaining fabric

VN = Shift Seam

S = Spacing or margin

ACP = Number of Correction (corrected??) Pleats CPL_B_1 = Corrected Pleat Length Panel 1

CPL_B_2 = etc.

CPL = Corrected Pleat Length

CPB = Corrected Pleat Section

AB = Number of Panels B_l = Panel 1 unpleated length

B_2 etc.

CB_1 = Corrected Panel 1 unpleated length

CB_2 etc.

VB_1 = Used Panel 1 unpleated length VB 2 etc.