GB1582227A

GB1582227A - Apparatus for use in and a method of hemming units of flexible sheet material

Info

Publication number: GB1582227A
Application number: GB4736975A
Authority: GB
Original assignee: Jenkins K T
Current assignee: Jenkins K T
Priority date: 1977-04-18
Filing date: 1977-04-18
Publication date: 1981-01-07

Description

(54) IMPROVEMENTS IN OR RELATING TO APPARATUS FOR USE IN AND A METHOD OF HEMMING UNITS OF FLEXIBLE SHEET MATERIAL (71) I, KENNETH THOMAS JENKINS, a British subject of 14 Blackfield Lane, Salford 7, Lancashire, do hereby declare the invention for which I pray that a Patent may be granted to me, and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to apparatus for use in and a method of hemming units of flexible sheet material, and it is an object of the present invention is to provide an apparatus and method which allows continuous and mass production in a precisely-controlled manner.

In my prior Patent Specification No. 1,249, 902 I disclose a method of cutting, folding and hemming sheet material wherein a continuous length of flexible sheet material resting in a relaxed condition on a work surface has transversely opposite portions of its longitudinal edges and a transverse strip of material between said opposite portions gripped and held, at spaced positions adjacent to and on each side of a predetermined position where the material is to be cut transverse its length, and, after cutting, a portion of material bordering each cut edge is folded to form the trailing hem of a leading material unit and a leading hem for a subsequent material unit.

My aforesaid Patent Specification also discloses apparatus for carrying out the aforesaid method, which apparatus includes carrier means for temporarily securing the folded trailing hem of a leading material unit and the folded leading hem for a subsequent material unit before the lateral edges of the material are released from the folding means, and, after such release, said carrier means being caused to move downstream to a position where said temporarily secured hems can be permanently secured to provide finished material units of predetermined length.

According to the present invention there is provided apparatus for producing sheet material units transversely hemmed from a batch or continuous supply of flexible sheet material comprising a first station mounting opposed upstream and downstream gyratory gripper means adapted to grip opposed edges of the sheet material and laterally tension same to permit a transverse cutting of the sheet material to be effected therebetween, a pin adjacent each gyratory gripper means and around which the latter gyrates at tension with the sheet material in a laterally relaxed condition to form a temporary hem, a carrier device for engaging each corner of each hem, laterally tensioningesame, and transporting same with its associated sheet material downstream to a second station at which is provided at least one pair of hem securing mechanisms movable between the adjacent temporary hems and adapted permanently to secure the hems longitudinally along their lateral edges and transversely across the width of the sheet material.

Preferably, the hem securing mechanisms is a pair of sewing machines arranged pulley end to pulley end with their major axes parallel to the direction of movement of the sheet material and their needles on a common longitudinal datum line parallel to the lateral edges of the sheet material.

In a modification, the sewing machines are replaced by heat and pressure welding units whereof the operative elements are mounted in the same relative positions as the sewing machine needles. This modification may be employed where the flexible sheet material is of a non-textile nature such, for example, as paper webs or webs made from plastics material or fibre-glass.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings in which: - Figure lisa pictorial view of the apparatus, and Figure 2 is a diagrammatic view of a folder gripper and sensor, and Figure 3 is a diagrammatic plan view of a "control side" of the apparatus showing upstream and downstream gripper platforms, and Figure 4 is a similar diagrammatic view to Figure 3 of the other and "adjustment side" of the apparatus showing upstream and downstream gripper platforms and the carrier track rails positioning platform, and, Figure 5 is a fragmentary cross-sectional view showing main support frames and carrier units of the apparatus, and Figure 6 is a transverse cross-section of the apparatus showing the hem-securing station, and Figure 7 is a view of the hem-securing station as seen at right-angles to the view of Figure 6, and Figure 8 is a view of a take-off gripper mechansim at one side of the apparatus, and Figure 9 is a diagram of a hem folding gripper unit mechanism, Figure 10 is a diagram showing the principal operational parts of a hem controlling mechanism, and Figure 11 is a diagram.showing a sheet material engaging foot of a carrier device.

The apparatus (Figure 1) comprises four main stations, namely a textile fabric supply station I; a gripping, cutting and temporary hemforming station II; a securing station III; and a folding and packaging station IV.

The apparatus is comprised of two parallel side frames 20 and 21, the frame 20 being called the "control" side of the apparatus and the frame 21 the "adjustment" side, which terms will be more fully explained later.

Referring to stage I, the textile fabric is fed from a batch supply 22 through nip rollers 23 to station II. The nip rollers 23 are controlled by a known rotary measuring device 24 which causes the nip rollers 23 to stop feeding when a required length of textile fabric has passed over the cutting line of stage II and indicated generally at 25, and there being a continuously running drag roller 26 downstream of the station II and over which the textile fabric passes to ensure that within station II and between the nip rollers 23 and the drag roller 26 said fabric lies in a flat plane.

With a view to reducing the length of the apparatus and to accommodate fabric which is surplus to the operational requirements of the apparatus, there is provided immediately downstream of the drag roller 26, a well 27 wherein surplus material rests during the sewing sequence of the operational cycle.

Upstream of the nip rollers 23 is a conventional cloth guiding apparatus 28 to ensure that the textile fabric is without longitudinal creases and to provide that one edge of the fabric lies on predetermined longitidunal control datum line at "control" side 20.

It is a requirement that the transverse hems of material units such for example as curtains and sheets are permanently secured not only along and near to the inner transverse edge of each hem but also along and near to the laterial ends of both hems, and'in connection with this requirement it should be noted that textile fabrics such as are used in the manufacture of curtains and sheets may, in a relaxed condition as when presented to station II, vary in width by as much as plus or minus 0.75% of the nominal width.

It should also be noted that in a hem-securing operation such as is required for the transverse securing of a hem, it is necessary to apply a certain control tension to the textile fabric along the direction of securing to ensure that the securing is performed along predetermined paths.

Referring to Figures 1,2 and 9, there is provided at station II four gripping and folding assemblies (see especially Figure 9), two on side frame 20 and the other two on side frame 21 which in use control a transverse rectangular strip of the textile fabric. In effect (see Figure 1) there is a pair of upstream assemblies 29 and a pair of downstream assemblies 30, the cutting line 25 being centrally disposed in this rectangular fabric strip.

Each assembly 29 or 30 comprises a gyratory gripper 31 which gyrates about an adjacent pin 32, spaced from the cutting line, and there being at a further spacing from the cutting line an anchoring gripper 33. The gyratory gripper 31 is carried on a pivotal arm 33A movable through 1800 by gearing 34, the gripper 31 additionally rotating through 180 relative to the arm 33A so that it, in effect travels through 360". Thus, assuming the textile fabric has been cut and the assemblies moved as described later to relax the textile fabric it will be manifest the gyration of opposed grippers 31 about pins 32 will fold the fabric upon itself and in-turn the raw or free edge between the superimposed fold layers. Such an arrangement is generally disclosed in my aforesaid Patent Specification.

Referring to Figure 3 which diagrammatically shows the "control" side of the apparatus at which the cloth guiding means 28 has placed one edge of the fabric on a predetermined longitudinal datum line of the apparatus, each assembly 29 or 30 is supported on a platform 35 movable towards or away from the corresponding fabric edge by a pneumatically operable ram 36 and a hydraulically operable ram 37 arranged in tandem, with the piston rod 38 of ram 37 positively fixed to the platform 35 and the piston rod 39 of ram 36 fixed to a stationary element 40 of side frame 20. The ram 36 serves to move the platform 35 from a "rest" position where its assembly 34 is clear of the fabric edge td a position where the sensing of said edge is to be started, and the ram 37 serves thereafter to continue platform movement until said edge has been sensed and the fabric gripped by the jaws of the grippers of each assembly.

The sensing operation is later described with reference to the "adjustment" side of the apparatus.

Each gripper/pin/gripper assembly of which only gyratory gripper 31 is shown has an associated air-jet sensor 41 (Figure 2). Each sensor 41 is carried by the piston rod 42 of an airoperable ram 43 connected as diagrammatically shown by ducts 44, 45 to the air supply of the associated grippers.

Each gripper has jaws 46 connected by pivotal linkage 47 to the piston rod 48 of a double-acting pneumatic ram 49 in communication with ram 43 via ducts 44, 45. The ram 49 is connected to its pressure air supply and valve control via ducts 50, 51. It will be manifest reciprocal movement of the piston rod 48 will open and close the gripper jaws 46.

The sensor 41 is essentially U-shaped with air passages 52 fed from the air supply via the duct 51.

In operation, when the platforms are to be moved towards the fabric edges 54, the gripper jaws 46 are opened and simultaneously the pistons 55 of the sensor rams 43 cause the sensors 41 to move from the rest position behind the gripper surfaces of the gripper jaws 46 towards a position where they will straddle the edge 54, the activating power being supplied to each piston through air duct 51 which also supplied pressure air for opening the gripper jaws and to air-jets 56 of the sensor.' When a platform reaches the position where its sensor air jets 56 are interrupted by the edge 54, a signal from the sensor, carried through another air duct 53 causes the actuation of means (as hereinafter described) which instantly stops further advance movement of the platform, after which pressure-air from a duct 50 causes the gripper jaws 46 to close and at the same time causes the sensor piston 55 to withdraw the sensor 41 to its rest position. It is to be noted that the closing of all gripper jaws and the withdrawal of all sensors is accomplished before a further step in the operational cycle of the apparatus is commenced.

It follows that the aforesaid edge sensing ensures that irrespective of any acceptable width variations of the textile fabric being processed, all grippers will close and grip the fabric in the same relationship to the extreme edges thereof, this being of great importance, as will be explained later, in ensuring that the permanent securing of the lateral edges of the hems will always be at a predetermined distance from the edges of the texfile fabric.

At the "adjustment" side of the apparatus (see Figures 4 and 5) the simultaneous moving of both upstream and downstream gripperlpinl gripper assembly platforms 57 towards or away from the fabric edge is accomplished by the following means.

Each platform 57 is driven along its path by the piston of a hydraulically operable ram 58 the cylinder of which is positively fixed to a link-bar 59 common to both platforms 57, said link-bar 59 having positively fixed thereto the cylinder of a pneumatically operable ram 60, the piston of which is fast with a connecting element 61 which, when the platforms 57 advance towards the fabric edge, is engaged by extensions 62 of both platforms 57 in such manner that the advancement of either or both platforms 57 causes the piston of the ram 60 to be advanced relative to its cylinder.Also mounted on the link-bar 59 and co-axial with the ram 60 is a pneumatically operable ram 63, the stroke of which can be pre-adjusted and the piston of which is permanently attached to a laterally movable framework 64 supported from part of the side-frame 21, which framework 64 is positively located in position by a hydraulic ram 65, the purpose for which will be explained hereinafter, the complete arrangement providing that activation of ram 63 moves both platforms 57 from a "rest" position to a position where the sensing for the fabric edge is to be started, and the subsequent activation of both rams 58 continues the movement of the platforms 57 independently of one another until the sensor 41 of each platform has sensed the edge, stopped the movement of the platform 57, and caused the gripper jaws 46 to grip the fabric, at which position the connecting element 61 associated with ram 60 will have caused its piston to have been advanced through the same distance as the most furtherly advanced of the two platforms 57, and in this connection it should be noted that, irrespective of the total acceptable width variations of the textile fabric, width variations in that length of fabric which extends between the upstream and the down-stream grippers will be relatively small and consequently the amount of advancement of either platform relative to the other will also be small.

Referring to the laterally movable framework 64 and its hydraulic ram 65, it may here be noted that where the cutting, folding, and sewing apparatus is required to process materials which differ considerably in nominal width, e.g. 50" wide, 70" wide, and 100" wide, the hydraulic ram 65 is used to place the framework 64 and associated gripping and folding mechanisms in the applicable relationships to the opposed mechanisms at the "control" side of the apparatus.

In operation, the closing of all the gripper jaws of the upstream and downstream platforms at both sides of the apparatus, and the withdrawal of their associated sensors initiates the commencement of the next step in the operational cyle of the apparatus. At the "control" side, the upstream and downstream hydraulic rams 37 are deactivated so that the extreme edge of the fabric gripped by the grippers is moved so as to lie precisely on a common longitudinal datum line of the apparatus irrespective of any small displacements from the datum line which was predetermined by the edge guide system 28.At the same time, at the "adjustment" side of the apparatus the hydraulic lock on the hydraulic rams 57 is released and the pneumatic ram 60 is activated in such manner that the connecting link 61 is retracted to withdraw the most furtherly advanced platform 57 until both platforms lie on a common longitudinal datum line of the apparatus, thus ensuring that the extreme edges of the fabric gripped by the rotating gripper jaws will also lie on a common longitudinal datum line of the apparatus, and it must here be noted that the lateral position of this latter datum line is determined by the actual width of that part of the fabric which is being processed irrespective of whatever the plus or minus allowable variations from the nominal width of the relaxed fabric might be.

Thereafter, at the adjustment side of the apparatus, the ram 63 is deactivated to retract the platforms 57 by an amount predetermined as being that which will straighten the weft of the gripped fabric and induce therein the lateral tension required for the cutting of the fabric and thereafter the automatic cutting is effected in the known manner. The cutting is effected as is disclosed in my aforesaid Patent Specification by a rotary cutting blade (not shown) which is reciprocable across the width of the apparatus.

After completion of the cutting operation, the ram 63 is reactivated to cause the platforms 57 to restore the cut fabric to a relaxed condition, and thereafter the upstream leading hem and the downstream trailing hem are simultaneously formed as previously described and are made ready for having their lateral edges temporarily secured by locking pins extending from transporting carrier devices.

For the purpose of engaging and temporarily securing the lateral edges of the folded hems, each carrier device 66 (Figure 5) is slidably carried in a sleeve 67 and is movable downwardly against the action of a spring 68 towards the folded hem along a path parallel to the axes of the pins 69 on a carrier foot 70 of the carrier device 66.

The pins 69 are parallel to one another and inclined towards the associated lateral edge of the hem and arranged on the foot 70 in a pattern which defines the lines along which the associated hem will be secured at the hemsecuring station. The pattern of pins 69 is indicated in Figure 11 and the foot 70 is formed with an L-shaped slot 71 open at one end which is provided to allow passage of a sewing needle as described later. Each carrier device is supported on a carriage 72 arranged to run on longitudinal guide rails 73 extending from the station II to the sewing station III, the guide rails at the "control" side of the apparatus being fixed to the main associated side-frame 20 and the guide rails at the "adjustment" side of the apparatus being fixed to a second laterally movable framework 74 (Figures 4 and 5) slidably supported from the main sideframe 21.This laterally movable framework 74 is connected to the laterally movable framework 64 by a pneumatic ram 75 and a hydraulic ram 76 arranged in tandem, the piston rod of the hydraulic ram 76 being positively fixed to the laterally movable framework 74, and the piston rod of the pneumatic ram 75 being fixed to the laterally movable framework 64. The stroke of the pneumatic ram 75 is adjustable so that it can be preset to transmit a movement equal to the amount decided as being that which will induce a desired lateral (securing) tension in the folded hems.

At the "adjustment" side of the apparatus, the longitudinal guide rails 73 which support the carrier devices are, downstream of station II, supported, immediately upstream and downstream of station III, on sets of laterally movable frameworks similar to, and operated in unision with, those at station II, said sets each comprising a first laterally movable framework 64, a hydraulic ram 65, a second laterally movable framework 74, and a pneumatic ram 75 arranged in tandem with a hydraulic ram 76.

At that stage of the operational cycle when the folded hems are ready for having their lateral edges temporarily secured by the pins 69 of the transporting carrier units, the hemsecuring operations on previously prepared hems have almost been completed at station III and the rams 75 are in their retracted conditions thus, causing the carrier devices to induce in the hems being secured, the lateral tension required for the securing operation.

As soon as the hem-securing operation has been completed in the manner described hereinafter, the carrier devices are released from the permanently secured hems and the rams 75 are all activated in unison for the full amount of their preset strokes thus causing all the laterally movable frameworks 74, and consequently the associated longitudinal guide rails 73, to be moved towards the plane of the edges of the folded hems.

Immediately thereafter, a pneumatic sensor system mounted on an extension of the second laterally movable framework 74 at the cutting and folding station causes the hydraulic rams 76 to move all said laterally movable frameworks 74 towards or away from the plane of the hem edges until said sensor system has positively located the position of the connecting element 61 (Figure 4) whereat said hydraulic rams 76 lock against further movement.

At this stage of the operational cycle, the longitudinal guide rails 73 at both control side and adjustment side of the apparatus are precisely located at positions as related to the actual transverse width of the relaxed hems that when the carrier devices have returned from the hem-securing station to station II and have been covered so that the pins therof engage and temporarily secure the folded hems, the securing lines defined by the pattern of said pins will be in predetermined relationships to the edges of the hems irrespective of whatever the actual transverse width of the hems may be.

It will be appreciated that whatever the acceptable material width variations may be, the actual changes in material width between successive cycles of the apparatus are seldom likely to be of a large order, and therefore the amount of time required to bring the laterally movable frameworks 74 into the required relationship with said connecting element 61, and consequently with the lateral edges of the folded hems is generally of very small order.

When the carrier devices have returned to their appropriate positions at station II, pneumatic rams 77 (Figure 5) mounted from the frameworks which support the longitudinal guide rails 73 at both sides of the apparatus are activated to lower the carrier devices until the pins thereof have engaged the folded hems.

The rams 77 are thereafter deactivated but leave the carriers retained in the engaged condition by latches 78 mounted on the carrier support.

After deactivation of rams 77 all gripper jaws are. caused to open, and simultaneously the pneumatic rams 36 of the control side and the hydraulic rams 58 and the pneumatic ram 63 of the adjustment side of the apparatus are deactivated to cause all gripper carrying platforms to withdraw to a position where all associated parts are completely clear of the edges of the fabric, leaving the folded hems solely controlled in a temporarily secured condition by the carrier pins. The folding grippers are then rotated to their normal positions in readiness for the next successive operational cycle.

As soon as the gripper jaws have released the edges of the fabric the pneumatic rams 75 associated with all the laterally movable frameworks 74 at the adjustment side of the apparatus are deactivated in unison causing all said frameworks with associated guide rails and carrier devices to be moved in the same direction as, but at a slower speed than, the retracting platforms, and for the distance predetermined as being that which will induce in the temporarily secured hems the amount of lateral tension required during hem-securing operations.

At this stage of the operational cycle the temporarily secured and laterally tensioned hems are ready to be transported by the carrier devices to the hem-securing station III.

The upstream and downstream carrier devices at both sides of the apparatus are connected together by pneumatically operable rams (not shown) whereof the stroke can be pre-adjusted to provide that when said rams are fully retracted at station II each carrier device will be so located relative to the cutting line that its pins 69 will be precisely positioned to engage that width of hem which it will be required to secure temporarily, and also to provide that at hem-securing station III the carrier devices are held apart at a distance which will permit the hem-securing rig carrying a pair of sewing machines arranged pulley end to pulley end with their major axes parallel to the direction of longitudinal movement of the fabric, to pass along the resulting transverse gap between the trailing hem and following leading hem.

The upstream pair of carrier devices is movable between its position at station II and its position at station III by a coupled pair of endless chains arranged one at each side of the apparatus, each chain including a selector bar provided with holes spaced apart longitudinally at, say, one quarter inch intervals for a distance related to the predetermined range of widths of leading hems which may be required, said selector bar being so arranged relative to the associated carrier devices that for any predetermined width of hem the carrier device can be coupled, to its driving chain in the appropriate hole in the selector bar.On one of the chains is a clevis attached to a pneumatically operable ram system (not shown) having a stroke equal to the distance between the cutting line of the apparatus and the position at the hem-securing station where such leading hem will be permanently secured.

The carrier device transporting arrangement is such that both upstream and downstream temporarily secured and laterally tensed hems are placed precisely in the positions at the hem-securing station III where the sewing machines will secure the hems along the lines predetermined automatically at station II.

The hem-securing sewing station III incorporates a "securing" rig comprising two sewing machines 79, 80 (Figure 6) mounted pulley end to pulley end with their major axes parallel to the direction of movement of the tektile fabric and their needles on a common datum line parallel to the lateral edges of the fabric, each machine being mounted on a respective sub-carriage 81,82 arranged to slide relatively upstream or downstream on a main carriage 83 which is transversely movable across the apparatus from a parking position outside the longitudinal path of the textile fabric at each side of the apparatus (see for example Figure 1).

To automatically secure a hem permanently by sewing it is desirable to closure sew one of the lateral edges of the hem longitudinally from a position near the corner of the hem to a position near the inner edge of said hem, then, without stopping the operation of the sewing machine, to sew transversely along and parallel to said inner edge to a position similarly close to the other lateral edge of the hem and then again without stopping the operation of the sewing machine, to transfer the direction of sewing so as to longitudinally closure-sew that edge of the hem longitudinally to a position near its longitudinally outer extreme corner. It will be manifest that slots 71 in carrier feet 70 allow this.

The sewing machines are driven in unison by a common motor 84 (Figure 7) mounted with its major axis parallel to those of the sewing machines, on said main frame 83, the drive to the sewing machines 79, 80 being through the intermediary of geared drive belt 85, counter-shaft 86 and splined couplings 87 (Figure 6) which permit the sewing machines 79, 80 to be moved upstream or downstream in accordance with longitudinal movements of their respective subcarriage 81, 82.

The upstream/downstream movement of each sub-carriage is effected by a linkage ststem 88 (Figure 6), incorporating a bellcrank 89, pivotally connecting the subcarriage 81 or 82 to said main carriage 83, both linkage systems being movable in unison by a common hydraulically operable ram 90 mounted on the main carriage 83, and both bell < ranks 89 being so arranged that the positions of the pivots of each can be pre-adjusted to provide that the full stroke of the ram 90 will cause each of the sub-carriages 81, 82 to be moved by exactly that amount required to closure-sew the lateral edges of the associated hems.

The transverse movement of the main carriage, and the sewing machines, between said parking positions may be effected by a hydraulically operable ram driving an endless chain or wire rope system, or by other known equivalent means.

Gate stops (not shown) are provided at each parking position to temporarily stop transverse movement when the needles of the sewing machines have been brought into alignment with a longitudinal datum line along which the associated lateral edges of the hems are to be sewn. At this stage, the ram 90 is activated to cause the sub-carriages 81, 82 with their sewing machines 79, 80 to move apart at a controlled speed until the lateral edges at that side of the two hems have been closure sewn.The ram 90 is then hydraulically locked and the gate stop automatically opened to allow transverse movement of the main carriage to continue and thus perform the permanent securing of the inner edges of the hems until the sewing machine needles coincide with the other longitudinal datum line when the transverse movement of the main carriage will again be stopped by a gate stop and the ram 90 activated to cause the sub-carriages with their sewing machines to move towards one another at a controlled speed until both sub-carriages have simultaneously reached their normal positions where the sewing action of the sewing machines will be stopped and the upper and lower sewing threads automatically cut in known manner.

Immediately thereafter the operative gate stops will be automatically opened to allow the transverse movement of the main carriage to continue until it reaches its parking position.

The gate stops ensure that when the sewing machine needles enter into coincidence with a longitudinal sewing line the main carriage is stopped. The gate stops at the "adjustment" side is of course, mounted on the laterally movable framework 74.

In order to ensure that the fold positions' temporarily secured by the pins of the carrier devices are not disturbed by friction resulting from contact with the upper surface of the sewing machine bed or other part of the hem-securing rig, it is provided that when the temporarily secured hems are presented to the hem-securing station they are so positioned that their mean level is such that the fabric in the hem is at least j/4" above the level of said surfaces, such positioning also providing that said surfaces can pass freely below the points of the pins of the carrier devices.

To accommodate this condition the customary throat plate of each sewing machine is provided with a substantially cubic raised part 93 (Figure 10) approximately 1/4" high which surrounds the hole through which the machine needle passes to form a stitch.

It is also provided that the sewing machine foot which normally prevents "flagging" of the fabric being sewn and holds said fabric in engagement with transporting dog elements of the machine is replaced by a foot with a bottom surface whereof the area is less than that of the raised part 93 of the machine throat plate and not greater than is necessary to strip the fabric of the hem from a rising needle, said foot being adjustably mounted so that the distance from its bottom surface to the upper surface of said raised part can be preset so that when the foot is in its operative condition it will permit free passage of the hem between the foot and raised part 93.

To ensure that the fold positions established by the folding mechanisms are maintained during a transverse hem-securing operation, there is provided a hem controlling mechanism mounted on each subcarriage 81, 82 so that it can be automatically moved into or out of its operative condition in accordance with the direction of movement of the sewing machines.

Such a hem controlling mechanism includes a freely rotatable horizontal roller 94 (Figure 10) arranged to engage the underside of the bottom layer of fabric in the hem, and a freely rotatable horizontal roller 95 arranged to engage the upper side of the top layer of fabric in the hem, the axes of both rollers being normally at right-angles to the direction of transverse movement of the machines, but both rollers being so supported that their axes can be adjustably orientated in the horizontal plane through an angular range of OC to 10 Both rollers are provided with a resilient surface which will ensure that the friction between their surfaces and the surface of contiguous she sheet material is greater than that between contiguous surfaces of upper and lower layers of the fabric. The rotatable horizontal roller 94 is so positioned that the axial extremity thereof which is remote from the sewing machine is substantially vertically below the position to be taken by the inner fold of the hem being secured.

Also included in the hem controlling mechanisms are hook elements 96 which, when transverse securing starts, latch over the inner fold of the hem at a position where it is clearly defined by the adjacent carrier device and thereafter, as transverse securing proceeds, serve to manipulate the fabric towards which the sewing machine is being moved so that the predetermined fold positions and stitch lines are maintained.In association with said hook elements is a first sensor element associated with the means whereby the orientation of the axis of the rotatable horizontal roller 94 can be adjusted, and a second sensor element associated with the means whereby the orientation of the axis of the rotatable horizontal roller 95 can be adjusted, the arrangement providing that if there is any tendency for the position of the transverse edge of the outer fold of the hem to vary, said first sensor causes the axis of the freely rotatable horizontal roller 94 to be re-orientated so as to urge the lower layer of fabric towards or away from the sewing machine, as required, and similarly if there is any tendency to variation in the amount of fabric available for the maintenance of the required fold lines, said second sensor causes the axis of the freely rotatable horizontal roller 95 to be re-orientated to cause the upper layer of fabric to be urged towards or away from the sewing machine.

Usually it will be found that the precise orientation of the roller axes can be predetermined according to the nature of the fabric being processed, and the adjustment means can then be preset and locked, in which case the sensors can be dispensed with.

At both parking positions there are take-off grippers 90 (Figure 8) carried from supports mounted so as to be longitudinally movable on transit rails 91 which extend downstream from the sewing station III to the folding and packaging station IV. When the main carriage 83 is parked, rams 92 move the grippers 90 into positions where their open jaws straddle the thickness of the fabric adjacent to the permanently secured lateral edges of the hem sewn by the upstream sewing machine.

When the grippers 90 grip said fabric, the latches 78 (Figure 5) are released to allow the carrier devices 66 to move upwardly away from the hems. As soon as the carrier devices have been released, a pneumatically ram controlled transporting means moves the grippers 90 downstream to a position within an automatic folding and packaging means of known kind where the grippers release the hem and adjacent fabric onto a drag roller or the like which will thereafter take control of the fabric units passed to it. The take-off grippers are thereafter automatically withdrawn from the path of the fabric and their supports are returned to the take-off position.

At this stage of the operational cycle, the trailing hem of a leading textile fabric unit has been permanently secured and said fabric unit, the leading hem of which was permanently secured during the preceding operational cycle, has been released entirely into the control of the folding and packaging means, and the leading hem for a next following textile fabric unit has been permanently secured and passed to a position within the folding and packaging means where the associated fabric unit will be held until its trailing hem has been duly formed and permanently secured during the next subsequent operational cycle.

Releasing of the carrier devices from the permanently secured hems starts the operation for moving the adjustment side carrier guide rails laterally to the position where the carrier devices at that side of the apparatus are in a position temporarily to secure the folded hems and they are returned to station II.

From the foregoing it will be seen that flexible sheet fabric supplied to the apparatus in a relaxed condition is subjected at the cutting and folding station to the following automatically performed controlling and mani pulsating operations: a. A predetermined length of the fabric is fed across a transverse line along which the material to be cut.

b. Irrespective of whatever the nominal width of the fabric may be, the actual width thereof at opposed positions adjacent said line is determined and the fabric edges are gripped so that a transverse rectangular area extending upstream and downstream of said line is taken into control.

c. The opposed lateral edges of the controlled area of the fabric are moved apart by an amount pre-determined as that which will straighten the weft of the fabric and induce therein a lateral tension which will facilitate cutting.

d. The fabric is cut across its entire width.

e. The opposed lateral edges of the cut fabric are restored to their original "relaxed" positions.

f. The portions of the fabric immediately up stream and downstream of the cut edges are formed into in-turned hems of a required width.

g. The lateral edges of the folded hems are temporarily secured by pins of transporting carrier devices.

h. Control of the fabric is transferred to said carrier devices by opening and withdrawal of the gripper jaws.

i. The transversely opposed lateral edges of the folded hems are moved apart by carriers through a distance predetermined as being that which will induce in the fabric of said hems the amount of lateral tension best suited for the operation of permanently securing, by stewing, hems made from the particular fabric.

It will also be seen that folded hems which have been transported by carrier devices to predetermined positions in the hem-securing station will, thereat, be automatically sub jected to the following permanent securing and manipulating operations: a. The hems are secured along longitudinal and lateral lines which respectively are at a predetermined distance from the inner folds of the hems.

b. The permanently secured hems are released from the carrier devices and are transported into a folding and packaging means.

There may be four sewing machines employ ed, two for each hem. For each hem a sewing machine will sew the longitudinal hem at its corresponding side, then move across trans versely and sew part of the transverse length of the hem and finally sew longitudinally for hem length to complete its sewing action. Ideally, each sewing machine would sew one half of the hem width but it is more likely that one will do one half and the other more than one half to ensure full hemming. To avoid collision one machine commences its transverse movement prior to the other. Each machine preferably operates in a vertical closed circuit path thus starting from a low parking position, elevating to effect hemming, lowering below fabric level and back to parking position.

Given the sequence of operations herein before described the fluid (pneumatic and hydraulic) circuitry, valve operations and other driving and control mechanisms referred to would be readily produced by 9 person skilled in the art and for this reason these aspects of the apparatus according to the present invention are not illustrated or des cribed in detail.

WHAT I CLAIM IS: 1. Apparatus fpr producing sheet material units transversely hemmed from a batch or continuous supply of flexible sheet material comprising a first station mounting opposed upstream and downstream gyratory gripper means adapted to grip opposed edges of the sheet material and laterally tension same to permit a transverse cutting of the sheet material to be effected therebetween, a pin adjacent each gyratory gripper means and around which the latter gyrates at tension with the sheet material in a laterally relaxed condition to form a temporary hem, a carrier device for engaging each corner of each hem, laterally tensioning same, and transporting same with its associated sheet material downstream to a second station at which is provided at least one pair of hem securing mechanisms movable between the adjacent temporary hems and adapted permanently to secure the hems longitudinally along their lateral edges and transversely across the width of the sheet material.

2. Apparatus as claimed in Claim 1 in which the hem securing mechanism is a pair of sewing machines arranged with their pulleys adjacent one another and with their major axes parallel to the direction of movement of the sheet material and their needles on a common longitudinal datum line parallel to the lateral edges of the sheet material.

3. Apparatus as claimed in Claims 1 or 2, wherein there is provided adjacent to the gripper means, edge sensing means that automatically detect the whereabouts of the lateral edges of the flexible sheet material, and upon detection of said edges so control the sheet material - approaching movements of the gripper means that, irrespective of the actual width of said sheet material, said appraoching movement is stopped and the sheet material is gripped when the gripper means are in a predetermined relationship to the edges of said sheet material.

4. Apparatus as claimed in any one of Claims 1 to 3, wherein each carrier device has locking pins extending from a foot to secure the folded hem, which pins are arranged in a pattern which defines the longitudinal and transverse lines along which a temporarily secured hem will be permanently secured.

5. Apparatus as claimed in Claim 4 comprising means for transporting the carrier devices along tracks from the first station to the second station, which tracks are automatically moved transversely to a position where the pins, irrespective of the actual transverse width of the hemmed sheet material, engage and secure the lateral edges of the hems at a predetermined distance from the extremities of the edges thereof.

6. Apparatus as claimed in Claim 2 of any one of Claims 3 to 5, to when appendant to Claim 2 wherein the sewing machines are each mounted on a sub-carriage arranged to move relatively upstream and downstream on a main carriage which is transversely movable across the apparatus between parking positions outside the longitudinal path of movement of the flexible sheet material.

7. Apparatus as claimed in Claim 6, wherein means are provided whereby the relative upstream/downstream movement of each of the sub-carriages is effected by a linkage system incorporating a bell-crank and connecting the sub-carriage to the main carriage, both linkage systems being movable in unison by a common hydraulic ram mounted on the main carriage and there being provided means whereby the pivot positions of both bell-cranks can be adjusted to vary the amount of upstream and downstream movements of their associated sub-carriages.

8. Apparatus as claimed in Claims 6 or 7, wherein there is provided gate stop means whereby the transverse movement of the sewing machines is automatically halted when the transverse position of the needles thereof coincide with a longitudinal datum line along which a lateral associated edge of a hem is to be secured longitudinally, said gate stops being automatically positioned in accordance with the actual transverse width of hems to be secured during the related operational

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. station will, thereat, be automatically sub jected to the following permanent securing and manipulating operations: a. The hems are secured along longitudinal and lateral lines which respectively are at a predetermined distance from the inner folds of the hems. b. The permanently secured hems are released from the carrier devices and are transported into a folding and packaging means. There may be four sewing machines employ ed, two for each hem. For each hem a sewing machine will sew the longitudinal hem at its corresponding side, then move across trans versely and sew part of the transverse length of the hem and finally sew longitudinally for hem length to complete its sewing action. Ideally, each sewing machine would sew one half of the hem width but it is more likely that one will do one half and the other more than one half to ensure full hemming. To avoid collision one machine commences its transverse movement prior to the other. Each machine preferably operates in a vertical closed circuit path thus starting from a low parking position, elevating to effect hemming, lowering below fabric level and back to parking position. Given the sequence of operations herein before described the fluid (pneumatic and hydraulic) circuitry, valve operations and other driving and control mechanisms referred to would be readily produced by 9 person skilled in the art and for this reason these aspects of the apparatus according to the present invention are not illustrated or des cribed in detail. WHAT I CLAIM IS:

1. Apparatus fpr producing sheet material units transversely hemmed from a batch or continuous supply of flexible sheet material comprising a first station mounting opposed upstream and downstream gyratory gripper means adapted to grip opposed edges of the sheet material and laterally tension same to permit a transverse cutting of the sheet material to be effected therebetween, a pin adjacent each gyratory gripper means and around which the latter gyrates at tension with the sheet material in a laterally relaxed condition to form a temporary hem, a carrier device for engaging each corner of each hem, laterally tensioning same, and transporting same with its associated sheet material downstream to a second station at which is provided at least one pair of hem securing mechanisms movable between the adjacent temporary hems and adapted permanently to secure the hems longitudinally along their lateral edges and transversely across the width of the sheet material.

cycle and being so automatically controlled that they immediately release the stoppage of transverse movement when a related hem edge has been automatically secured longitudinally.

9. Apparatus as claimed in any one of Claims 1 to 8, wherein there is provided at the second sheet station, gripping means which engage and grip the sheet material at opposed positions adjacent the lateral edges of upstream hems after the hems have been permanently secured, and thereafter disengaged the hems from the carrier devices and transfer them to a folding and packaging means where the complete flexible sheet material units are automatically folded and packaged for distribution.

10. Apparatus as claimed in Claim 2, wherein the throat plate which forms part of the surface of the bed plate of each sewing machine is provided with a substantially cubic raised part which surrounds the hole through which the machine needle passes to form a stitch, said raised part serving to raise the level of the sewing plane to a level where the sheet material being sewn is clear of the surface of the sewing machine bed and associated equipment.

11. Apparatus as claimed in Claim 10, wherein the sewing machine is provided with a foot having a bottom surface whereof the area is less than that of the raised part of a sewing machine throat plate and not greater than is necessary to strip the sheet material being sewn from a rising needle, said foot being adjustably mounted so that the distance from its bottom surface to the upper surface of a raised part of the sewing machine throat plate can be pre-set to such condition as will ensure that in the operative position of said foot it will allow the free passage of the hem between the foot and the raised part of the throat plate.

12. Apparatus as claimed in Claim 2, wherein each sewing machine has an automatic hem-controlling mechanism mounted in such a manner that it is automatically moved into or out of its operative condition in accordance with the direction of movement of the sewing machine so that during a transverse hem-securing operation the part of the hem being approached by said sensing apparatus is under control of said controlling means.

13. Apparatus as claimed in Claim 12, wherein each hem-controlling mechanism includes two freely rotatable horizontal rollers one of which frictionally engages the underside of the sheet material in the bottom layer of a hem being secured, and the other frictionally engages the upper side of the top layer of said hem, the axes of both rollers being normally at right-angles to the direction of transverse movement of the associated sewing machine but being adjustably orientatable through a horizontal angular range of 00 - 10", and the axial extremity of the lower roller which is remote from the associated sewing maching being substantially vertically below the position to be taken by the inner fold of the hem being secured.

14. Apparatus as claimed in Claim 12 or 13, wherein a hem-controlling mechanism also includes hook elements which latch over the inner fold of a hem to be secured at a position where said fold is clearly defined by an adjacent transporting carrier, said hook elements serving to manipulate the sheet material towards which the associated sewing machine is moving, and there being in association with said hook elements and the freely rotatable horizontal rollers, sensor elements, by which the orientation of the axes of said rollers can be adjusted so as to cause the sheet material engaged by the rollers to maintain the defined fold positions and switch lines during hem-securing operations.

15. Apparatus for producing sheet material units transversely hemmed, substantially as described herein and illustrated in the accompanying drawings.

16. Apparatus as claimed in Claim 2 in which the sewing machines are replaced by heat and pressure welding units whereof the operative elements are mounted in the same relative positions as the sewing machine needles.

17. A method of producing transversely hemmed sheet material units, wherein a continuous length of flexible sheet material in a relaxed condition has transversely opposite portions of its longitudinal edges gripped and held, at spaced positions, adjacent to and on each side of a predetermined position where the sheet material is to be cut transverse its length, and, after cutting, portions of sheet material bordering each cut edge are folded substantially simultaneously to form the trailing hem of a leading sheet material unit and a leading hem for a next following sheet material unit, characterised in that prior to the gripping of the sheet material the gripping means are located by sensing means which ensure that, irrespective of the actual width of the sheet material, the gripping means will always grip the sheet material in a predetermined relationship to the extreme edges thereof, and also characterised in that after folding of said hems they are temporarily secured so as to be firmly held in position during subsequent operations whereby a predetermined lateral tension is induced in the hems and retained therein during transportation to hem-securing means whereby the longitudinal and lateral edges of the hems are permanently secured.

18. A method as claimed in Claim 17, performed on apparatus substantially as described herein and illustrated in the accompanying drawings.

19. Sheet material units of measured length cut from a continuous length of flexible sheet material in a relaxed condition and having transverse hems folded and secured by apparatus as claimed in any one of Claims 1 to 16 and/or the method claimed in Claim 17 or 18.