FOR GRIPPING A FLEXIBLE PANEL

The present invention relates to an apparatus for assembling flexible articles, and a method of assembling flexible articles. In particular, but not exclusively, the invention relates to an apparatus for assembling garments, for example by sewing together fabric panels and subassemblies of fabric panels, and a method thereof.

It should be understood that the apparatus and the method described herein are not restricted to the assembly of garments and may be utilised for the assembly of other flexible articles, for example upholstery covers. Also, although such articles are usually assembled by sewing together fabric panels and sub-assemblies of fabric panels, the invention is not limited to the use of sewing as a joining method and may be utilised with other joining methods, for example using adhesives or ultrasonic welding. Also, the invention is not limited to the use of fabric panels, but is also applicable to the joining together, whether by sewing or otherwise, of flexible panels made of other materials including, for example, leather or polymeric sheets. However, it is envisaged the invention will be of application mainly to the assembly of garments by sewing together of fabric panels.

An objective of this invention is to enable the automation of some 60% of the garment assembly and sewing process. Garment assembly & sewing is almost universally a manual operation carried out by operators working on a sewing machine - the operators carry out all the fabric plies handling, assembly, alignment and tensioning, and guiding functions up to the sewing machine. This activity is very labour intensive, and garment manufacturers have been seeking automation methods to reduce labour content and costs.

About 30% of the garment sewing task involves the seaming together of two flat but variably sized and shaped fabric workpieces along a common edge. The resulting joined sub- assembly can then be either flat or it will have a three dimensional "shape" and no longer sit flat when resting on a flat surface. Because both workpieces are flat before being sewn together, they can be guided easily through the sewing machine and this process is therefore relatively simple to automate.

Another 30% of the garment sewing task involves the seaming together of one flat but variably sized and shaped fabric workpiece to a sewn sub-assembly, which is not flat in itself, along a common edge. The resulting joined sub-assembly will also have a three dimensional "shape" and will not sit flat when resting on a flat surface. This process of sewing together a flat fabric panel and a non-flat fabric sub-assembly to create a three dimensional garment in a given body shape is more difficult to automate. A further part of the garment sewing task involves the seaming together the opposed edges of a multi-panelled sewn sub-assembly, which may be flat or not flat in itself, to form the full three dimensional assembly. For example, this may involve sewing the last seam to transform a non-flat, four panel sewn sub-assembly into a tubular skirt. The resulting joined final assembly will have a three dimensional "shape" and is a three dimensional form. The present invention addresses at least some of the above objectives and is comprised of flexible workpiece handling hardware under pseudo artificial intelligence (AI) control so it is fully flexible to handle and sew a range of fabric workpieces and shapes in the flat or non- flat forms that make up a garment. The invention is also applicable to a method of seaming a three dimensional "shaped" sub-assembly to a flat fabric panel. Full three dimensional handling and sewing is not addressed by this invention.

Accordingly to one aspect of the invention there is provided a method of assembling a flexible article comprising a plurality of flexible panels, the method comprising (a) arranging a first flexible panel having a first edge so that at least the first edge of the first flexible panel has a flat configuration, (b) arranging a second flexible panel having a first edge and a second edge so that at least the first edge of the second flexible panel has a flat configuration, (c) attaching a gripper device to the second flexible panel to hold the second edge in a fixed configuration, (d) seaming the first edge of the first flexible panel to the first edge of the second flexible panel to form a sub-assembly of flexible panels, (e) re-positioning the second flexible panel by means of the gripper device while maintaining the second edge in the fixed configuration, and (f) seaming the second edge of the second flexible panel to a flexible element, wherein said flexible element is either a third flexible panel, or said first flexible panel, or a subassembly of flexible panels.

This process may be repeated as many times as necessary to add additional flexible panels to the second and subsequent sub-assemblies. It should be noted that the first and second flexible panels are arranged with the respective first edges in a flat configuration, allowing those edges to be seamed together using a static or mobile seaming device, for example a sewing machine.

An important feature of the invention relates to the fact that at each stage of the assembly process the gripper device or some other shape retention and control means is attached to the second edge of each additional flexible panel before another edge (e.g. the first edge) of the panel is seamed to another flexible panel or element. This ensures that the second edge is engaged and held in a fixed configuration before the flexible panel is distorted by the subsequent seaming process.

It should be noted that the process is applicable to any stage of the process for assembling flexible articles, for example when sewing together sub-assemblies of a dress, a car seat cover or a pillow case, and relates to the seaming together of flexible panels or subassemblies, regardless of the stage at which they are seamed together.

Optionally, but not essentially, the gripper device is attached to the second edge of each additional flexible panel while the panel is flat and undistorted: i.e. while the second edge of the panel is still in its flat state. The gripper device then holds the second edge in its flat shape while aligning that edge with the first edge of the next panel, allowing those edges to be sewn or otherwise joined together. The second edge is therefore gripped and controlled before it gets distorted during the new seaming operation. After the seaming operation has been completed, the resulting new sub-assembly is ready for manipulation and positioning for seaming to the next additional panel. However, it should be noted that it is also possible in certain circumstances to attach the gripper device to the second edge of the flexible panel while the panel is arranged in a non-flat but controlled configuration. This may be necessary when, for example, the flexible panel is part of a subassembly of panels that has a non-flat shape. It should be understood that the first and second flexible panels mentioned above do not necessarily have to be the first and second panels of a garment or other flexible article to be attached together. For example, the said second panel may be part of a sub-assembly of flexible panels that have already been joined together. The method is applicable to any of the flexible panels that make up a flexible article. It should also be understood that the first and subsequent sub-assemblies may have a flat shape or a non-flat shape. Finally, it should be noted that step (c), attaching a gripper device to the second flexible panel to hold the second edge in a fixed configuration, can take place earlier in the process, for example before step (a) or step (b). In an embodiment, the edges of said flexible panels are seamed together by sewing. The flexible panels may for example be fabric panels.

In an embodiment, the method further comprises aligning the first edge of the first flexible panel with the first edge of the second flexible panel before seaming the first edge of the first flexible panel to the first edge of a second flexible panel. In an embodiment, the edges of the flexible panels are aligned using an optical position sensing system.

In an embodiment, the gripper device has an adaptable shape, the method comprising adapting the shape of the gripper device to match the shape of the second edge before attaching the gripper device to the second edge of the second flexible panel.

Alternatively the gripper device may have a fixed shape, and have a grip area that is sufficient to substantially encompass and overlap the second edge of the additional flexible panel.

In another embodiment, the gripper device comprises part of a support element, for example a shuttle plate, that supports the first or second flexible panel, rather than being a separate device. In this case the support element may include a mechanism for gripping a second edge of the flexible panel, for example a low-profile electro-adhesive device, while still allowing for necessary movement of the flexible panel for guiding through the seaming machine. In this embodiment a separate gripper device may still be required to pick up and turn over the second flexible panel after seaming, so that it can be seamed to another flexible element. In an embodiment, the method further comprises inverting the second flexible panel before seaming the second edge of the second flexible panel to a flexible element. This inverting process is necessary for sub-assemblies in which the panel elements and the seams need to be all facing the same direction (noting that panel elements usually have "front face" and the "back face" - the front face being the face that is seen on the outside of the garment.

In an embodiment, the gripper device has first and second gripper elements configured to engage the second flexible panel on opposite sides thereof, the method including transferring the second flexible panel from the first gripping element to the second gripping element before inverting the second flexible panel. In an embodiment, the method includes placing the first and second flexible panels on lower and upper shuttle plates respectively, and moving the shuttle plates relative to the seaming machine to form the first seam. The seaming machine may for example be a sewing machine.

Accordingly to another aspect of the invention there is provided an apparatus for assembling a flexible article comprising a plurality of flexible panels, the apparatus comprising first support means for supporting a first fabric panel having a first edge so that at least the first edge of the first flexible panel has a substantially flat configuration, second support means for supporting a second fabric panel having a first edge and a second edge so that at least the first edge of the second flexible panel has a substantially flat configuration, a gripper device configured for attachment to the second flexible panel to maintain the second edge of the second flexible panel in a fixed configuration, a seaming machine for seaming together the first edges of said first and second flexible panels to form a first seam, the first and second flexible panels together comprising a first sub-assembly of flexible panels, a re-positioning device attached to the gripper device for re-positioning said second flexible panel while maintaining the second edge of the second flexible panel in said fixed configuration, and seaming said second edge of the second flexible panel to a flexible element, wherein said flexible element is either a third flexible panel, or said first flexible panel, or a subassembly of flexible panels.

The first and second support means for supporting the first and second fabric panels may each comprise flat plates. Alternatively, one or both of the support means may be non-flat, for example cylindrical, conical or any other shape, as required to hold a non-flat flexible panel or subassembly of panels, in a predetermined configuration or shape.

In an embodiment, the seaming machine is a sewing machine.

In an embodiment, the apparatus includes an optical position sensing system for aligning the edges of the flexible panels.

In an embodiment, the gripper device has an adaptable shape, and is configured to be adapted to match the shape of the second edge of the second flexible panel before the gripper device is attached to the second edge of the second flexible panel.

In an embodiment, the gripper device comprises first and second gripper elements configured to engage the second flexible panel on opposite sides thereof.

In an embodiment, the gripper device is configured to invert the second flexible panel before seaming the second edge of the second flexible panel to the flexible element.

In an embodiment, the apparatus includes lower and upper shuttle plates for supporting the first and second flexible panels and moving the flexible panels relative to the seaming machine to form the first seam.

According to another aspect of the invention there is provided a gripper device for gripping a flexible panel having a first edge, so as to maintain the first edge in a fixed configuration, wherein the gripper device includes first and second gripper elements that are adapted to grip the flexible panel on opposite sides thereof. In an embodiment, each gripper element is configured to grip the flexible panel

independently.

In an embodiment, the gripper device is configured to transfer the flexible panel between the first and second gripper elements.

In an embodiment, each gripper element has an adaptable shape and is configured to be adapted to match a shape of the first edge of the flexible panel before the gripper device is attached to the flexible panel. In an embodiment, the gripper device includes a base element, wherein the first and second gripping elements are pivotally attached to the base element.

In an embodiment, the gripper device includes a docking device for selectably attaching and detaching said first and second gripping elements to and from the base element. The core technology elements that are required to support a fully flexible Robotic Feeding, Assembly & Sewing Technology workstation (RFAST Workstation) comprise the following four key technology elements:

Element 1. Universal fabric work-piece gripper for non-distorting, full-surface engagement, that is effective for a wide range of fabric weights and types. Element 2. Universal top fabric ply separator and rest of fabric stack retention means, for range of fabric workpiece shapes and sizes, and effective for a wide range of fabric weights and types.

Element 3. A universal sewn fabric sub-assembly handling means to engage any sewn subassembly and re-position it for assembly to another successive flat workpiece panel, and for feed up to a Smart Sewing machine.

Element 4: A Smart Sewing Machine with localised control for automatic edge tracking, work-pieces edge matching, fullness creation, automatic feeding and individual ply steering/stretching through the sew-foot, effective for a wide range of fabric weights and types, and effective for almost all workpiece shapes encountered in garments. Embodiments of the invention described herein address the above Elements 1, 2 and 3 as an integrated system. The remaining Element 4 is under development by others.

The main innovative features of the invention are as follows:

1. The Universal flat-bed fabric work-piece robot gripper which provides non-distorting, and full-surface engagement for the fabric workpiece, effective for wide range of fabric weights and types. 2. A universal top fabric ply separator and rest of fabric stack retention means that can handle a wide range of fabric workpiece shapes and sizes, and effective for wide range of fabric weights and types.

3. A universal sewn fabric sub-assembly handling means to engage any sewn sub-assembly and re-position it for assembly to another successive flat workpiece panel.

4. A system comprising the above three features, integrated with a Smart Sewing Machine that forms the fully flexible Robotic Feeding, Assembly & Sewing Technology (RFAST) Workstation.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, wherein:

Figures 1-12 illustrate the steps of a method of assembling a fabric article according to a first embodiment of the invention, and components of an apparatus for assembling fabric articles,

Figures 13-18 illustrate the steps of a second method of assembling fabric articles, according to another embodiment of the invention, and elements of an apparatus for assembling fabric articles, and

Figure 19 illustrates a variant of the second method.

With reference to figure 1, in this example a method of assembling a garment comprising a four panelled skirt will be described. Each skirt consists of four flat fabric panels, here designated panels (T) @ @ and ©. These panels are pre-cut and stacked as illustrated, where the panels (T) in the first stack have the front face F of the fabric uppermost and the panels @ @ © in the other stacks all have the back face B of the fabric uppermost. The edges of the panels that are to be seamed together (i.e. joined) are designated by the reference numbers 1-14. Notches N are sometimes cut in the edges of the panels to aid the longitudinal alignment of the edges whilst seaming. Optionally, a top ply separator may be provided to aid separation of the top fabric panel from the remainder of the stack, and clamping means may be provided to clamp down the rest of the stack. These elements are conventional and are not shown in the drawings, and will not be described in further detail. A method of assembling a skirt from the four fabric panels may for example comprise the following steps:

Operation one: seam edge 1-2 to edge 5-6

Operation two: seam edge 3-4 to edge 9-10 Operation three: seam edge 7-8 to edge 3-14.

Finally, the skirt will be completed by seaming edge 11-12 to edge 15-16.

In operation one, panel (T) is joined to panel @ by placing panel @ on top of panel (T) so that the front faces F of the panels face one another, and then aligning and sewing together edges 1-2 and 5-6. This process, including picking up the panels from the stack, placing them together face to face, aligning the edges and sewing the edges together may be fully automated and completed using conventional apparatus including, for example, an automatic sewing machine (ASM) with optical edge locating means and fabric manipulating devices for aligning the edges of the fabric panels during seaming. It should be noted that both panels (T), @ are flat prior to seaming. Operation one is illustrated in more detail in figure 2. The fabric panels (T), @ may, if required, be supported on smooth metal separator panels P, which allow the positions of the fabric panels (T), @ adjusted individually. The first corner CI of the first panel (T), at the start of edge 1-2, is aligned with the first corner C2 at the start of edge 5-6, under the sew foot of the ASM (not shown). The ASM sews the corners CI, C2 together and the panels (T), @ are then fed under the sew foot to seam together edges 1-2 and 5-6. The ASM matches and aligns the edges 1-2, 5-6 of the panels (T), @ as they are drawn under the sew foot and at the same time eases the fabric panels to align the notches N.

For the ASM to carry out its function, the fabric panels 1 and 2 do not have to be flat, but substantial flatness will make the edge steering and matching operations easier to carry out. So, in the illustrations that follow, these panels are kept flat or substantially flat for engineering expedience, but does not in concept need to be flat.

Operation one in a method according to an embodiment of the present invention is shown in figures 3-8, while operation two (the seaming together of edges 3-4 and 9-10) is illustrated in figures 9-12. With the reference first to figure 3, in step A the first fabric panel (T) is taken robotically by a flat bed gripper device from the first stack and placed on a stainless steel lower shuttle plate LSP. The position of the first fabric panel (T) is sensed by an optical sensing system, for example comprising an upwards looking camera C, and adjusted to align the first corner 1 of edge 1-2 with a target T.

In step B (figure 4) an upper shuttle plate USP is moved into position above the lower shuttle plate LSP, leaving a small gap (for example about 10mm) between the two plates.

In step C (figure 5) the second fabric panel @ is taken from the second stack by a flat bed gripper device and placed on the upper shuttle plate USP. The position of the second panel © is sensed using an optical sensing system, and adjusted to align the first corner 5 of edge 5-6 with the target T. This ensures that the first corners 1, 5 are aligned with each other.

In step D (figure 6), the upper and lower shuttle plates USP, LSP are moved towards the automatic sewing machine ASM to place the corners 1, 5 of the fabric panels (T), @ under the needle of the ASM. In step E (figure 7) a robotic gripper device G is attached to the upper fabric panel @ adjacent a second edge 3-4 of the panel, which is located away from the first edge 5-6 that has already been placed beneath the needle of the ASM. In this embodiment the gripper device G comprises a pair of gripper elements GE1, GE2 that can pivot towards and away from each other, and a base element GB to which the gripper elements GE1, GE2 are attached. The base element GB is configured to be attached to a robotic arm, allowing it to be moved in three dimensions and rotated as required. Each gripper element GE1, GE2 is flexible and includes an adjusting mechanism (not shown) for adjusting the shape of the gripper element, at least in a two dimensional plane, to match the flat shape of an edge of a piece of fabric. The term "flat shape" as used herein in relation to an edge of a piece of fabric, means the shape of that edge when the fabric is lying flat without wrinkles or creases on a smooth, flat surface. Each gripper element also includes a gripper mechanism allowing it to grip and hold a piece of fabric, and release the fabric when required. Many different types of gripper mechanism may be used including, for example, gripper pins, a vacuum system or an electrostatic gripper system. Before the first gripper element GEl is attached to the second fabric panel @, the adjusting mechanism inside the gripper element is activated (if required) to match the shape of the gripper element to the flat shape of the second edge 3-4 of the second fabric panel @, for example using the optical sensing system. The first gripper element GEl is then attached to the fabric panel @ close to the second edge 3-4. This ensures that the flat shape of the second edge 3-4 can be maintained even after the first edge 5-6 has been seamed to the edge 1-2 of the first fabric panel (T), and during subsequent manipulation of the sub-assembly SAl comprising the joined panels (T), @.

In step F (figure 8) the automatic sewing machine ASM is activated to sew together the edges 1-2, 5-6 of the first and second fabric panels (T), @, forming a first seam SI . The upper and lower shuttle plates USP, LSP and the robotic gripper device G move synchronously to position the edges 1-2, 5-6 correctly beneath the needle of the ASM as the seam SI is sewn.

Once the seam has been completed, as shown in figure 9, the ASM will be located at the opposite end of the seam, adjacent ends 2, 6, so that the sub-assembly SAl comprising the first and second panels (T), @ is downstream of the ASM. In step G (figure 9), the lower shuttle plate LSP is withdrawn and returns to the start position, allowing the sub-assembly SAl to drape over the edge of the upper shuttle plate USP, where it is held by the gripper device G.

In step H (figure 10) the robotic arm attached to the gripper device G lifts the sub-assembly SAl so that the sub-assembly hangs from the gripper device G. The two gripper elements GEl, GE2 close to grip the edge 3-4 between the two gripper elements. The first gripper element GEl then releases the sub-assembly, while the second gripper element GE2 engages it, thereby transferring the sub-assembly SAl from the first gripper element GEl to the second gripper element GE2. In step I (figure 11), the robotic arm and the gripper device G place the sub-assembly SAl on the lower shuttle plate LSP with one end 3 of the edge 3-4 located at the target position T. The robotic arm may also be programmed to fold the sub-assembly neatly onto the lower shuttle plate LSP, as illustrated in figure 11. Because the edge 3-4 is gripped by the gripper device G and held in its flat shape it can be precisely positioned in the correct location. Optionally, securing means may be used to maintain the edge 3-4 or at least the leading end of that edge 3, in the as-placed position. As an illustration, such securing means, may be an electro-adhesive element integrated into the LSP (and/or UPS).

In step J (figure 12) the gripper device G releases the sub-assembly SA1 and the robotic arm retracts, moving the gripper device G away from the sub-assembly. The upper shuttle plate USP then returns to the start position above the lower shuttle plate LSP, and a flat bed gripper then places the third fabric panel @ on the upper shuttle plate USP with end 9 of edge 9-10 in the target position T. The automatic sewing machine ASM then sews together with edges 3-4 and 9-10 of the sub-assembly SA1 and the third fabric panel @, to form a second seam S2. This process is repeated to attach the fourth fabric panel © to the third fabric panel @, by sewing edge 13-14 to edge 7-8 to form a third seam S3. Finally, the skirt is completed by sewing edge 11-12 to edge 15-16, to form a fourth seam S4 (this operation being normally completed by a human machinist).

However, additional automation can be utilised to automate the completion of the skirt by sewing edge 11-12 to edge 15-16, to form a fourth seam S4, that will result in the substantially tubular sub-assembly. The concept to perform this additional automated step is described below.

A further embodiment of the invention is illustrated in figures 13 to 18. This embodiment relates to a method of seaming a three dimensional "shaped" sub-assembly SA2 to a flat fabric panel P.

In step 1 (top drawing) the sub-assembly SA2 is placed on a three dimensional shaped bottom trough BT, the shape of the bottom trough being designed to allow the sub-assembly SA2 to lie smoothly, without substantial folds or creases, in full contact with the bottom trough BT. One end XI of the sub-assembly SA2 is aligned with a target T, wherein the end XI comprises one end of a first edge El that is to be joined to a second edge E2 of the flat fabric panel P. The top plate TP is displaced to one side to allow access to the bottom trough BT. In step 2 (second drawing) a gripper device G, which may for example be similar to the gripper device G described above, is attached to the sub-assembly SA2 adjacent a third edge E3 that is located away from the first edge El .

In step 3 (third drawing), the top plate TP is brought into alignment above the bottom trough BT.

In step 4 (bottom drawing), the flat fabric panel P is placed on the top plate TP with one end X2 of the second edge E2 aligned with the target T, and with the first end XI .

Referring to figure 14, in step 5 a robot flexible right side gripper GR is attached to a second edge E4 of the flat panel P, which is located away from the first edge E2.

In step 6 (middle drawing) the top plate TP and the bottom trough BT move synchronously to carry the first and second edges El, E2 of the flat panel P and the sub-assembly SA2 past the seaming machine, to join the edges El, E2 together. In step 7 (bottom drawing) the bottom trough BT and the robot flexible gripper GR move back to the start position and the robot flexible gripper GR then lifts the rear edge E4 of the flat panel P away from the sub-assembly SA2.

Referring to figure 15, in step 8 (top drawing) the robot flexible gripper GR lifts the rear edge E4 of the flat panel P still further.

In step 9 (middle drawing) the robot gripper "changes hand" by transferring the flat panel P from the right hand gripper GR to the left hand flexible gripper GL. The robot also repositions the anchor gripper G in to the lower part of the bottom trough BT.

In step 10 (bottom drawing) the robot lays the flat panel P over the upper contoured portion of the bottom trough BT and aligns the corner X2 with the target T. If the next stage comprises closing a "tube" by sewing a last seam, this is achieved as shown in step 20 (figure 18). Otherwise, the process continues as follows. Ref erring to figure 16, in step 11 (top drawing) the top plate TP slides back into position above the bottom trough BT. In step 12 (bottom drawing) a second flat panel P2 is laid on the top plate TP with a first corner X3 aligned with the target T. The aligned edges of the first panel P and the second panel P2 are then seamed together (step 13) substantially as described above in step 6 (figure 14). Steps 6 to 12 can then be repeated as necessary to add successive panels.

Figure 17 illustrates a gripper device G that can be used in connection with this embodiment of the invention. The gripper device includes a base portion GB that can be attached to a robot arm, and a pair of docking heads that are pivotally attached to the base portion, comprising a right side gripper GR and a left side gripper GL. The right and left side grippers can pivot through an angle of 90° relative to the base portion GB, as indicated by the arrows A in figure 17. The gripper device G may also include a plurality of flexible plane grippers Gl, G2, G3, which can be attached independently to one or other of the docking heads. The flexible plain grippers are configured to be adaptable to the shape of an edge of a fabric panel, and also retain that shape when detached/un-docked from the docking head. The flexible grippers can be picked up or left behind by the robot by attachment/detachment from the respective docking heads GL, GR.

Referring to figure 18, the final steps for joining together a tubular fabric article will now be described, this continues from step 6 as described above. In step 20 (top drawing) the robot docks the right side gripper GR and picks up the anchor gripper AG previously located in the bottom trough part of the bottom trough BT.

It should be noted that in this embodiment the top plate TP is divided into, say, three portions, TP1, TP2, TP3.

In step 21 (middle drawing) the robot "changes hands" so that the rear edge of the subassembly SA2 is gripped on its opposite side by the reshaped left side gripper GL. In step 22 (bottom drawing) the relevant part of the top plate TP (in this case the first part TPl) slides back to the start position above the bottom trough BT. The robot then lays the bottom portion of the sub-assembly SA2 over the portion TPl of the top plate and aligns the leading edge of that fabric with the target T. The aligned edges of the sub-assembly are then seamed together, substantially as described in step 6 above.

Referring to figure 19, a variant of the bottom trough plate design is illustrated, which allows consistent placement of the anchor gripper despite the variable lengths of fabric sub-assembly. The bottom trough includes an anchor gripper holding shelf, which supports the anchor gripper AG while attached to one edge of the sub-assembly SA, and a second shelf S2 that is separated from the holding shelf HS, to provide a narrow gap between the two shelves. The fabric sub-assembly SA can hang in a loop between the two shelves, thus allowing the bottom trough plate to accommodate different lengths of sub- assembly.