FIELD OF THE INVENTION The present invention relates to an apparatus for making pleated fibrous webs and a method of making pleated fibrous webs. In particular, the present invention relates to textile lapping machines.

BACKGROUND OF THE INVENTION

Previous textile lapping machines and methods have suffered from a number of limitations and problems that reduce their efficiency and/or effectiveness, and which can render them generally inconvenient to use and difficult to adjust for use in producing differently sized products.

For example, previous machines have introduced the web into the area in which lapping occurs in a generally vertical manner and over a relatively long distance, allowing the web to stretch and potentially pull apart as it "falls". This method can result in a pleated web of lower quality and having increased imperfections, and can also limit the weight of the web used as it must have sufficient strength to support its own weight over a relatively long distance so as to remain continuous once stretched.

Furthermore, previous machines have used a reciprocal comb box which is angled away from a vertical plane, causing imbalance upon reciprocation and complex vibrations in both horizontal and vertical planes, which can be very difficult to dampen. The magnitude of these vibrations can vary as differently sized pleated webs are produced, further increasing the difficultly of effective damping these vibrations for a number of different modes of machine operation. Also, previous presser bar arrangements have been generally ineffective as there can be interaction or physical interference between the comb and presser bar, thereby limiting the potential speed at which a pleated web can be produced. Furthermore, previous presser bar arrangements have also been vulnerable to contamination as they have comprised a planer front face, which causes turbulence behind the presser bar that can draw the web or only some of the fibres of the web behind the plate and into contact with the drive units and surfaces covered in lubricating oil.

Furthermore, previous machines have been complicated with the comb and presser bar mechanically linked, thereby making the machine difficult to adjust if a differently sized pleated web is required.

Examples of the invention seek to solve, or at least ameliorate, one or more disadvantages of previous apparatus and methods for making pleated fibrous webs.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided an apparatus for making pleated fibrous webs, comprising a comb reciprocable along a generally vertical path and a reciprocable presser bar which cooperates with the comb to pleat the web, the comb configured for moving the web in a first direction and the presser bar configured for moving the web in a second direction which is substantially perpendicular to the first direction, wherein the machine further comprises a conveyor belt for introducing the web, the conveyor belt having a suction system to draw the web onto the conveyor belt.

According to another aspect of the present invention, there is provided an apparatus for making pleated fibrous webs, comprising a reciprocable comb for moving the web in a first direction and a reciprocable presser bar for moving the web in a second direction, the comb and the presser bar cooperating to pleat the web, wherein the machine further comprises a conveyor belt for introducing the web, the conveyor belt having a suction system to draw the web onto the conveyor belt. According to another aspect of the present invention, there is provided an apparatus for making pleated fibrous webs, comprising a comb reciprocable along a generally vertical path and a reciprocable presser bar which cooperates with the comb to pleat the web, the comb configured for moving the web in a first direction and the presser bar configured for moving the web in a second direction which is substantially perpendicular to the first direction, wherein the comb and/or the presser bar are driven by a servo drive system.

According to another aspect of the present invention, there is provided an apparatus for making pleated fibrous webs, comprising a reciprocable comb for moving the web in a first direction and a reciprocable presser bar for moving the web in a second direction, the comb and the presser bar being driven by a servo drive system and configured to cooperate to pleat the web, wherein once pleated the web passes between a pair of vertically offset and parallel conveyor belts to transport the web, the position of a lower belt being movable to vary the separation of the belts for different sized pleats.

According to another aspect of the present invention, there is provided an apparatus for making pleated fibrous webs, comprising a reciprocable comb for moving the web in a first direction and a reciprocable presser bar for moving the web in a second direction, the comb and the presser bar cooperating to pleat the web, wherein once pleated the web passes between a pair of vertically offset and parallel conveyor belts to transport the web, the position of a lower belt being movable to vary the separation of the belts for different sized pleats.

It will be appreciated that preferred embodiments of the invention include a number of features which each provide different advantages and which may be combined in different combinations to achieve different advantageous results. It will also be appreciated that some embodiments may have only some of the described features.

According to a preferred embodiment, the parallel belts are generally horizontal. Preferably, the belts are configured for transporting the web to an oven. According to preferred embodiments, the web is introduced by a conveyor belt having a suction system to draw the web onto the conveyor belt.

Preferably, reciprocation of the comb is independent from reciprocation of the presser bar. The stroke of the pusher and the comb is preferably variable to vary a height of the pleated web being formed. Preferably, the stroke of the presser bar and the comb is varied via operation of a cam wheel having a plurality of differently configured apertures to which a connecting rod can be coupled. According to preferred embodiments, the comb and/or the presser bar are driven by a servo drive system. The servo drive system can include a servo motor and servo drive unit.

Preferably, the machine is configured to introduce the web for pleating at an angle below 40 degrees to a vertical plane.

Preferably, the first direction along which the comb reciprocates is substantially perpendicular to the second direction, along which the presser bar reciprocates. Preferably, the comb is reciprocable along a generally vertical path. According to another aspect of the present invention, there is provided a presser bar for a textile lapping machine for making pleated fibrous webs, the presser bar being configured for reciprocal movement and cooperation with a reciprocating comb to pleat the web, the presser bar including a forward face for contacting the web, a plurality of elongate needles extending from the forward face for piercing the web to bring fibres of nearby pleats into engagement with each other and a rearward support for supporting a rearward portion of the needles.

According to a preferred embodiment, the presser bar includes a member formed of a closed box section, a pair of opposed side walls of the member forming the forward face and the rearward support. Preferably, the plurality of needles extend through the opposing walls of the box section.

According to another aspect of the present invention, there is provided in combination, an apparatus of the above described type and a presser bar of the above described type

The combination can further comprise an oven for bonding the pleated web.

According to another aspect of the present invention, there is provided a method of making pleated fibrous webs, comprising the steps of: streaming the web; reciprocating a comb along a generally vertical first path and reciprocating a presser bar along a second path which is substantially perpendicular to the first path, the comb and the presser bar being configured for moving the web in respective first and second directions and cooperating to pleat the web; and introducing the web for pleating via a conveyor belt having a suction system for drawing the web onto the belt.

Preferably, the web is introduced at an angle below 40 degrees to a vertical plane.

BRIEF DESCRIPTION OF THE DRAWINGS Preferred embodiments of the invention will be further described, by way of non-limiting example only, with reference to the accompanying drawings in which:

Figure 1 is a side schematic view of a textile lapping machine of one embodiment of the invention;

Figure 2 is a close side view of the machine;

Figure 3 is another close side view of the machine in use;

Figure 4 is a close side view of a shark unit used to hold the web once pleated; Figures 5a and 5b are respective side and front views of a comb for use with the machine;

Figures 6a to 6d are side views of different presser bars for use with the machine; Figure 7 is another close side view of the machine showing different adjustment positions for a conveyor for introducing the web; Figure 8 is another close side view of the machine with a guide plate fitted;

Figures 9a and 9b are respective side and front views of a guide plate for use with the machine; and

Figures 10 and 11 are respective side and end views of a textile lapping machine of another embodiment of the invention;

Figures 12 and 13 are close side views of a presser bar and comb of the machine of Figure 10;

Figures 14A and 14B are schematic views of the path of movement of the presser bar and comb of the machine of Figure 10;

Figures 15 and 16 are respective front and side views of a cam wheel of the machine of Figure 10;

Figure 17 is a close sectional view showing a connecting rod fitted to the cam wheel; and

Figures 18 to 20 are front views of the cam wheel in different conditions of use.

DETAILED DESCRIPTION

With reference to Figure 1, there is shown an apparatus 10 according to a preferred embodiment of the present invention.

The apparatus 10 is configured for making pleated fibrous webs. The apparatus 10 comprises a reciprocable comb 12 and a reciprocable presser bar 14 which cooperate to pleat the web 16 as it passes through the machine. The comb 12 is configured for moving the web 16 in a first direction and the presser bar 14 is configured for moving the web in a second direction which is substantially perpendicular to the first direction. As can be seen in Figure 3, operation of the comb 12 and the presser 14 results in the web 16 being pleated.

The web 16 is introduced by an endless conveyor belt 18 having a suction system to draw the web 16 onto the conveyor belt 18. Advantageously, the web 16 is supported as it approaches the comb 12 and presser bar 14, thereby reducing the amount of stress applied to the web as it falls, reducing stretching of the web 16 and allowing lighter webs to be used. The conveyor belt 18 is configured so as to be adjustable both vertically and horizontally so that the positioning of the web 16 for introduction to the comb 12/presser bar 14 can be varied.

The comb 12 is reciprocable along a generally vertical path and the apparatus 10 is configured to introduce the web 16 for pleating at an angle below 40 degrees to a vertical plane. In a preferred embodiment, the angle is approximately 10 degrees. As the apparatus 10 uses a conveyor belt 18 having a suction system, the weight of the web 16 can supported so that is can be introduced at an angle which is closer to vertical, without introducing problems associated with stretching of the web before it is pleated.

By moving the comb 12 through a generally vertical path, the problems with vibrations encountered by previous textile lapping machines can be reduced and potentially avoided. In this regard, previous lapping machines have used a reciprocating comb that is angled to a vertical plane, causing vibrations in both the vertical and horizontal planes and making counterbalancing and damping very difficult. Vibrations in only a vertical plane can be damped with comparative ease using conventional damping methods that can be used over a variety of different operational speed. This allows the machine to operate over a faster speed range without incurring vibration related damage to the apparatus 10 or its surroundings.

By arranging the comb 12 so as to reciprocate through a generally vertical path, the presser 14 can be disposed generally perpendicular to the comb 12 so that interference or contact between the comb 12 and the presser 14 can be reduced or avoided as the spatial overlap is minimised. This allows the machine to operate at faster speeds without risking damage to the comb 12 or the presser bar 14.

The comb 12 is driven by a drive unit 20 incorporating a variable drive motor and gearbox and the presser bar 14 is driven by another drive unit 22 which also incorporates a variable drive motor and gearbox. Advantageously, reciprocation of the comb 12 can be controlled independently from reciprocation of the presser bar 14, thereby allowing operational adjustments to be easily made, as described further below.

Previous lapping machines have used a single drive unit that drives both the comb and the presser bar via belts. Because the comb and presser bar of previous machines are linked by the belts, their relative position is difficult to vary, making adjustment for producing differently sized webs difficult and time consuming. This problem is avoided by using independent drive units 20, 22 which can be independently adjusted to vary their operation as required.

Preferably, the vertical positioning of the drive unit 20 can be varied so that a pleated web having differently sized pleats can be made. It will be appreciated that the speed and stroke of the drive units 20, 22 may be variable depending on the characteristics of the web to be produced. In preferred embodiments, the drive units 20, 22 each include a servo drive system which includes a servo motor and servo drive unit, though it will be appreciated that other variable speed drive units may similarly be used. By using a servo drive system, operation of each drive unit can be accurately controlled as required. For example, the reciprocation speed can be easily adjusted, and if required, a delay in the reciprocation cycle can be added to provide additional clearance between the comb and spacer, potentially accommodating for different material characteristics of the different web materials used.

As illustrated in Figure 1 in broken lines, the drive unit 20 can be disposed above or below the web 16. By using independent drive units, there is more flexibility in how the apparatus 10 is assembled.

The illustrated machine 10 also includes a pair of vertically offset and parallel conveyor belts 30, 32 for transporting the web to an oven 34 once pleated. The oven 34 heats the pleated web to bond fibres in the web together, thereby securing the layers together. The position of a lower belt 32 is movable to vary the separation of the belts for different sized pleats. Previously, textile lapping machines have varied the vertical position of the upper belt 30 so as to accommodate differently sized pleats. By moving the upper belt 30, the position of the comb 12 and the pusher bar 14 also need to be moved to maintain the relationship between these components and the web to be pleated, thereby complicating adjustment of the machine for differently sized pleats. However, by varying the position of the lower belt 32, the relative positioning of the comb 12, presser bar 14 and conveyor 18 can be retained so that adjustment of the machine for producing different products can be performed faster and with less complication.

As illustrated in Figure 3, upper conveyor belt 30 passes around roller 31 and guide plate 35, and engages an upper side face of the pleated web to hold it in position while transporting the web to the oven 34. Lower conveyor belt 32 passes around roller 33 and guide plate 37, all of which are movable to allow the position of the lower belt 32 to be adjustable, and engages a lower side face of the pleated web. It will be appreciated that by using independent drive units 20, 22, it is possible to remove the mechanical linkage of important system components which constrained operation of previous machines. For example, using independent drive units 20, 22 the lower belt 32 can be modified so as to be adjustable to simplify the system and adjustment for differently sized pleated webs. Furthermore, the use of independent drive units 20,22 allows the comb 12 to be reciprocal along a generally vertical path and the presser bar 14 to be reciprocal along a generally horizontal path, thereby simplifying vibrations induced by the reciprocation so that the vibrations may be more effectively damped.

The belts 30, 32 are illustrated as being generally horizontal, though it will be appreciated that they may also be inclined or declined. Furthermore, the belts 30, 32 are shown as each being a single belt, though the machine may include a system of multiple interrelated belts.

The oven 34 is configured to accommodate variation in the separation of the belts for pleated webs of different thicknesses.

A stationary shark unit 19, as illustrated in Figure 3, is provided to engage the web and hold a pleat in position once the presser bar 14 pushes a further pleat into the pleated web. The shark unit 19 has a corrugated face plate which acts to prevent the newly formed pleat from following the presser bar 14 to a return position. The face plate of the shark unit may have a shark tooth formation that allows an edge of the pleat to easily move across the shark plate and toward the pleated web while restricting movement toward the presser bar 14.

As illustrated in Figure 8 and 9, a guide plate 21 may further be provided for guiding the web 16 toward the comb 12 and presser bar 14. The guide plate 21 has a curved cross section to allow the web to be guided from the conveyor to a more vertical orientation for pleating. The guide plate 21 may be adjustable, both in vertical and horizontal position, to allow differently sized pleated webs to be formed and to accommodate webs having different material characteristics. Figures 6a to 6d illustrate a number of differently configured presser bars 14a, 14b, 14c, 14d according to preferred embodiments. The presser bars are configured for use with the above described machine 10 for making pleated fibrous webs and are configured for reciprocal movement and cooperation with a reciprocating comb 12 to pleat the web. The presser bars include a forward face 32 for contacting the web, a plurality of elongate needles 34 extending from the forward face 32 for piercing the web to bring fibres of nearby pleats into engagement with each other and a rearward support 36 for supporting a rearward portion of the needles 34. The needles 34 pierce or puncture the pleats to bring the fibres of adjacent or nearby pleats into contact with each other so as to cross-link the different pleats and increase the strength of the pleated web in transverse planes and improve the webs resistance to pulling apart between the pleats under load. The needles 34 have barbs to push and pull fibres through the different layers of pleats as the needles 34 pierce the web.

The different presser bars are for use in producing differently sized webs. For example, presser bar 14a is configured for use with webs having a small pleat height and has a front face 32 with a low height and includes only a single row of needles 34. Presser bar 14b is configured for use with webs having a larger pleat and has two rows of needles 34. Presser bar 14c is configured for use with larger webs and has four rows of needles 34, and presser bar 14d is configured for use with again larger webs and has five rows of needles 34. It will be appreciated that larger presser bars having more than five rows of needles may also be possible. It will also be appreciated that the different presser bars are configured to be readily interchangeable to facilitate quick changes to machine setup.

In the illustrated embodiment, the pressers bar each include a member formed of a closed box section, a pair of opposed side walls of the member forming the forward face 32 and the rearward support 36. The plurality of needles 34 extend through the opposing walls of the box section.

Previous lapping machines have suffered from the web or some of its fibres being drawn behind the presser bar due to suction. By using a box section, the distance between the forward face and rearward support allows the previous void to be filled thereby increasing the distance from the web to a suction zone and reducing the chance of the web being drawn behind the presser bar 14 and potentially contaminated with lubricants used in the drive system. According to a preferred embodiment, there is provided a method of making pleated fibrous webs, comprising the steps of: streaming the web; reciprocating a comb along a generally vertical first path and reciprocating a presser bar along a second path which is substantially perpendicular to the first path, the comb and the presser bar being configured for moving the web in respective first and second directions and cooperating to pleat the web; and introducing the web for pleating via a conveyor belt having a suction system for drawing the web onto the belt. The web is introduced at an angle below 40 degrees to a vertical plane.

With reference to Figure 10, there is shown an apparatus 110 according to another embodiment of the present invention. The apparatus 110 is configured for making pleated fibrous webs and is similarly configured to apparatus 10 and like components have been given like reference numerals and the preceding description of apparatus 10 is intended to apply to apparatus 110.

In this regard, apparatus 110 comprises a reciprocable comb 112 and a reciprocable presser bar 114 which cooperate to pleat the web 116 as it passes through the machine. The comb 112 and presser bar 114 are shown in broken lines in their extended positions. The comb 112 is configured for moving the web 116 in a first direction and the presser bar 114 is configured for moving the web in a second direction. In a preferred form, the first and second directions are substantially perpendicular, though it will be appreciated that they may be otherwise arranged. Operation of the comb 112 and the presser 114 results in the web 116 being pleated, in a manner similar to that shown in Figure 3.

As can be seen in Figure 10, the web 116 is introduced between a pair of endless conveyor belts 118a, 118b. Advantageously, the web 116 is supported as it approaches the comb 112 and presser bar 114, thereby reducing the amount of stress applied to the web as it falls, reducing stretching of the web 116 and allowing lighter webs to be used. The conveyor belts 118a, 118b may be configured so as to be adjustable both vertically and horizontally so that the positioning of the web 116 for introduction to the comb 112/presser bar 114 can be varied.

The comb 112 is reciprocable along a generally vertical path and the apparatus 110 is configured to introduce the web 116 for pleating at an angle below 40 degrees to a vertical plane. In a preferred embodiment, the angle is approximately 10 degrees. As the apparatus 110 uses a pair of conveyor belts 118a, 118b, the weight of the web 116 can supported so that is can be introduced at an angle which is closer to vertical, without introducing problems associated with stretching of the web before it is pleated.

Those skilled in the art will appreciate that by moving the comb 112 through a generally vertical path, the advantages discussed above in relation to apparatus 10 will similarly apply to apparatus 110. Again, the apparatus 110 includes a pair of vertically offset and parallel conveyor belts 130, 132 passing around respective rollers 131 and 133 for holding the pleated web in position and transporting it to an oven 134 once pleated. The oven 134 heats the pleated web to bond fibres in the web together, thereby securing the layers. The position of a lower belt 132 is movable to vary the separation of the belts for different sized pleats, thereby providing the advantages discussed above.

The belts 130, 132 are illustrated as being generally horizontal, though it will be appreciated that they may also be inclined or declined. Furthermore, the belts 130, 132 are shown as each being a single belt, though the machine may include a system of multiple interrelated belts. Also, the oven 134 is configured to accommodate variation in the separation of the belts for pleated webs of different thicknesses.

As can be seen in Figure 11, the comb 112 and presser bar 114 are driven by a common motor 150, via belts 152 and 154 and gearboxes 156a/156b and 158a/158b. It will be appreciated that the comb 112 and presser bar 114 may be driven by separate drive units, which may incorporate a variable drive motor and gearbox, as per apparatus 10.

As illustrated in Figures 12 to 14, the comb 112 is preferably configured so as to reciprocate as close as possible to the shark unit 119 without coming into contact with it. This provides additional clearance for reciprocation of the pusher bar 1 14 as it moves along its path.

The inventor has found that a critical parameter in the height of the pleated web is the stroke of the pusher bar 114. After compression of the web 116 by the pusher bar 114, the streaming web 116 continues to fall, creating a loose portion of the web 116 extending from the compacted pleated section and which falls toward the retracting pusher bar 116 and is pushed downwardly by the comb 112. This loose portion is then pressed against the portion of the web which is already compacted on a subsequent extension of the pusher bar 114. It will be appreciated by those skilled in the art that it is the length of the loose portion that determines the height of the pleated fibrous web, this length being the distance between the compacted portion and a tip of the comb 112 in its lowermost position.

This realisation has led to the stroke of both the comb 112 and the pusher bar 114 being variable to create webs of different heights, thereby allowing webs to be formed of greater height than was previously possible. The maximum height of the pusher bar 114 for a given application can be calculated by dividing the stroke of the comb 112 by two and then subtracting the height of the shark 119, which in the present case is 3mm, and also subtracting a predetermined clearance allowance between the pusher bar 114 and the lower belt 132, which is preferably in the order of 10mm.

As can be seen in Figure 12, the presser bar 114 is configured so that a final third of movement of the presser bar 114, i.e. at the outermost extended position, is below the shark unit 119, with the initial two thirds of its movement being clear of the shark unit 119. Also, the comb 112 is configured so as to travel as close as possible to the belt in its extended position, whilst still providing clearance from the belt and any high points formed on the belt, such as a join. In this regard, in a fully extended position the comb 112 is no more than 1mm above the highest belt on the belt. Owing to the above configuration, the datum X of the apparatus 110, as indicated in Figures 12 and 13, is set at the level of the upper belt 130. To create larger sized webs, the lower belt 132 is lowered, the stroke of the comb 112 and presser bar 114 is increased and potentially a pusher bar 114 having a larger height is fitted. If differently sized teeth are provided on the shark unit 119, then the shark unit 119 may need to be lifted.

The path of the comb 112 is shown schematically in Figures 14A and 14B as path A-A, with the path of the presser bar 114 being illustrated as path B-B and the centre of reciprocation being marked as O for each path. It will also be appreciated that the stroke of the comb 112 is at least twice the height of the presser bar 114 so as to prevent interference or contact between the comb 112 and the presser bar 114. Figures 15 to 17 illustrate a cam wheel 160 that allows for relatively quick and easy adjustment of the stroke of the comb 112 and presser bar 114. The cam wheel 160 includes a cam disc 162 that is fitted to a hub 164 by a series of bolts 165. The cam wheel 160 has a plurality of apertures formed therein, each aperture being spaced from a centre of the cam wheel 160 a different amount. In the illustrated embodiment, three apertures 168a, 168b, 168c are provided, the apertures being spaced from a centre of the disc distances of 50mm, 90mm and 130mm respectively. It will be appreciated that the cam wheel 160 may be modified to include apertures that are spaced from the centre a different amount to form differently sized webs.

By fitting a connecting rod 172 (refer Figures 18 to 20) to different apertures using a pin 170, the magnitude of the reciprocating motion can be varied. As illustrated in Figure 16, the connecting rod is connected to the cam wheel 160 via a pin 170, a hub 174 and a bearing 176.

Figures 18 to 20 illustrate the cam wheel 160 in different conditions of use. Figure 18 illustrates a configuration that provides an 100mm stroke to create a 40mm web, Figure 19 illustrates a configuration that provides an 180mm stroke to create a 80mm web and Figure 20 illustrates a configuration that provides a 260mm stroke to create a 120mm web.

Apparatus 110 provides an improved apparatus for making pleated fibrous webs that allows webs to be formed with a height larger than previously possible. Also, the angle of the pleats can be varied for different applications and a substantially vertical pleat being achievable.

The embodiments have been described by way of example only and modifications are possible within the scope of the invention disclosed.