WO1989010321A1

WO1989010321A1 - Automatic small fabric pieces feeder

Info

Publication number: WO1989010321A1
Application number: PCT/AU1989/000167
Authority: WO
Inventors: Paul Charles Wong
Original assignee: Wong Paul C
Priority date: 1988-04-19
Filing date: 1989-04-19
Publication date: 1989-11-02

Abstract

An apparatus for the fast feeding of small fabric pieces (29, 31) for automatic sewing operations comprising means for the magazining of a number of stacks (15) of workpieces (29, 31) and automatically feeding each stack (15) to a feeding position, where a pickup and separation module which includes a pair of fabric grippers (8, 9) mounted at each end of a shuttle carriage (10) positioned to move across the axis of the stack (15) to sequentially position each gripper (8, 9) above the stack (15) will pick up individual workpieces (29, 31) from the stack (15) and feed them sequentially onto two offset conveyors (11, 12), and if required to be slightly overlapped, into an inverting module which includes two turnover chutes (27, 28) of identical length to invert every alternate workpiece (31) after which the workpieces (29, 31) will then feed into a folding/sewing module which will fold, hem or otherwise from the workpieces (29, 31) before stitching.

Description

AUTOMATIC SMALL PIECES FEEDER

BACKGROUND TO THE INVENTION

This invention relates to an apparatus for the fast feeding of small fabric workpieces for automatic sewing operations, where it may be optional to turn over each alternate workpiece so that the workpieces are fed into the sewing module all faced up. More particularly, but not exclusively, the invention is applicable to the automatic pick up and feeding of fabric strips from paired stacks into a folder and sewing machine for the making of continuous belt loop strips ( which are subsequently cut for use on trousers ). A "paired" stack of fabric strips is one where every alternate strip is facing upside down, this results from cutting the stack from a fabric pile that has been unrolled and Z folded, like computer paper, into a pile.

In the apparel industry, there are many manual tasks that involves the operator feeding small fabric workpieces, one at a time from a stack, into various joining, hemming, or folding and stitching operations. The operator normally sits in front of the sewing machine with a stack of fabric pieces on her lap, and feeds one piece at a time into the sewing machine. If the the stack is paired, ie each alternate workpiece is faced down, then the operator must invert these pieces prior to feed in, so that all pieces are fed into the sewing machine faced up. Depending on the operation, the strips may need to be joined into a continuous strip, as for example, in the continuous belt loop making operation where the discrete strips are fed into the sewing machine, nose to tail overlapped by about 10mm to form a continuous belt loop (which is later cut into individual loop length for attachment to pairs of trousers). If the raw strips are cut in paired stacks, then every alternate strips needs to be turned over prior to feeding. SUMMARY OF THE INVENTION

The object of the invention is an apparatus that will automatically pick-up and separate individual strips or pieces from a stack, perhaps invert every alternate one, and feed the strip or piece sequentially and slightly overlapped, if required, into a sewing machine.

The invention provides means for the magazining of a number of stacks of workpieces and automatically feeding each stack to a feeding position, where a pickup and separation module will pickup individual workpieces from the stack and feed them sequentially, and if required slightly overlapped, into an inverting module which will invert every alternate workpiece, after which the workpiece will then feed into the folding/sewing module, which will fold, hem, or otherwise form the workpiece before stitching it. See Fig 1 , where workpieces loaded in bulk onto the mgazining module, 1, will feed into the pick up and separation module, 2, where the workpieces are individually acquired and fed into the turnover module, 3, and finally into the folding/sewing module, 4 Clearly, a range of different automatic or semi-automatic systems may be put together with all or some of these modules to suit a specific operation.

Beyond the applications, described by way of example herewithin, the invention is applicable beyond the garment industry to task requiring a similar sequence of acquisition and manipulation functions.

Hereinafter, a preferred embodiment of the invention for use in the apparel industry will be described in detail by way of example, of the concept of the invention. BRIEF DESCRIPTION OF DRAWINGS

A preferred embodiment of the invention will be described with reference to the accompanying drawings in which:

Figure 1 is a block diagram sketch showing the relationship of the system's modules.

Figure 2 shows in diagrammatic form a preferred embodiment of the magazining module.

Figure 3 shows in diagrammatic form a preferred embodiment of the pick up and separation module.

Figure A shows a further aspect of the embodiment shown. in Fig 3.

Figure 5 shows a mechanism for ensuring separation of the gripped fabric workpiece and the rest of the stack.

Figure 6 shows a preferred embodiment of the turnover module.

DESCRIPTION OF PREFERRED EMBODIMENTS

In the following preferred embodiments of the various modules will be described.

A preferred, but not exclusive, form of implementing the storage and the magazining of the stacks, which allows the magazine to be refilled at any time without requiring that the automatic operation of the system be shut down, and a form which enables the operator to safely refill the magazine while the system is continuing operation is described. Fig 2 shows an indexing flat conveyor, 4, on which adjacent stacks, 5, of fabric strips are carefully placed across the conveyor to abut and align against the neighbouring stacks. When the system is turned on, the stacks will advance until the leading stack reaches the feed position - this position will abut the lead stack, 6, against an alignment fence 7 and its arrival is sensed by, say, an optical or contact sensor. As each stack is used up, its depletion is sensed by another sensor which, for example, detects that the bottom strip has been removed, and this signals the advance of the next stack into the feeding position. In this manner, further stacks can be loaded onto the magazine without interruption of the automatic feeding. Control program intelligence interpretting the signals of various sensors and the use of both time delays and overdrive of the stack against the alignment fence 7 is used to optimise the relaibility of accurate and repeatable positioning of the feed stack. The intermittent driving of the conveyor is by known means, such as an electric gearmotor, or clutch motor.

Other methods of presenting the magazine stacks can be by compartmenting the stacks each within fenced compartments on a special conveyor, or on conveying pallets.

The preferred implementation of a fast fabric pickup device is the use of a double independent gripper head arrangement, 8 & 9 mounted on a shuttle carriage, 10, feeding into offset conveyors, 1 1 and 12, respectively with each cycle of pickup and shuttle, as shown in Fig 3. Specifically, in the shown position in Fig 3, gripper 9 is actuated to descend on its guides, 14, to the top of the feed stack 15, the top piece is separated by a separation roller mechanism 16 (described later), and is lifted to the "up" position.

From here it is shuttled across to a position above the conveyor 12 by the movement of carriage 10, where the workpiece just picked up can be released when required by the control program onto conveyor 12, in the meantime, as soon as gripper 8 is in position above the feed stack 15, it can similarly pick up the new top piece off the stack. After the release of the previous piece by gripper 9, the carriage 10 can shuttle back, and the cycle repeated. The advantage of this arrangement is twofold - the first is that while one head is releasing its strip onto its offset conveyor, after moving sideways, the other gripper is over the stack picking up the next strip - this effectively halves the cycle time of the machine. The second advantage is that for a paired stack, the even numbered strips are picked up by one gripper head and the odd numbered strips are picked up by the other gripper head. Say that the odd numbered strips are all faced down, then the offset conveyor for this head would lead to a turnover device which will invert all these strips.

Fig 4 shows how, in order to reduce the mass of the gripper heads 16 & 17, so as to speed up the module's cycle time, the gripper heads can be made to grip only the front section of each strip 18, rather than over the entire length of the strip. However, as each strip is picked up and moved sideways, it is important to ensure that the tail which is hanging out to one side does not cause the strip 18 to mistrack after release to the conveyor, 19. A special tail locating device has been devised to ensure the tail of the strip 18 is trapped in a fixed position so that it alway feeds in from a constant rearward direction. The tail locating device comprises a holding collar, 20, with a bell mouth to facilitate entry, and a one way gate 21 to keep the tail within the collar 20 once the gripper has released it.

Fig 5 shows the stack separating mechanism. A small cylindrical drum 22 which contains a friction strip 23 sits with a small force on the leading edge of the stack, 24 When the gripper 25 descends onto the top of the stack as shown, the drum 22 is rotated a half turn in the clockwise direction and immediately reversed about its cylindrical axis; this action causes the top strip 26 to separate from the rest of the stack and ends up resting on top of the drum 22, as shown in the scrap view in Fig 5. When the gripper 24 is lifted with the gripped top strip 26 any stickiness between it and the rest of the stack 24 is countered by the drum 22 firmly sitting on the stack 24

The preferred implementation of the turnover function is by means of guide chutes, Fig 5. This implementation is compact and has the advantage of having the same travel length, which eases the control task of synchronizing the release of the strips at each release point, in order to achieve a constant spacing between workpieces or small tail/nose overlap. The module comprises a pair of guide chutes 27 and 28, each of the same travel length, but respectively, maintains surface orientation and inverts. A strip 29 feeding face up into the entry of the chute 27 will travel through the chute and emerge at its exit onto the transport conveyor 30, still face up. Similarly, a strip 31 , after going through the chute 29 will emerge onto the conveyor 30, inverted. If the strips are relatively stiff and long compared to the travel length of the chutes 27, 28 then the chutes can be simply flat guide tunnels, as shown, if the strips are soft or relatively short compared to the length of the chutes 27, 28 then it is necessary to provide a motive force on the strips while its in the chutes 27, 28; this motive force can be by any of the known means such as air jets, sychronized rollers, or by means of trapping conveyors.

Where the stack is not paired, the turnover chutes 27, 28 can be replaced by simply converging conveyors to deliver the strips from their separated infeed locations to a common exit location.

Lastly, the feed of the workpiece out of the turnover module into a folding/sewing module is straightforward.

The sequencing of the various machine functions to perform the pick up and feed task is also straight forward to those skilled in the art.

The description given as an example hereinabove, is meant to illustrate the concept by means of one implementation, the concept of the elements can be implemented in various forms and in other functions and combinations.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An automatic device for the automatic or semi automatic magazining, pick up and separation, the turnover of alternate workpieces when required, followed by the feeding of the workpieces into a processing module such as a sewing machine.

2. The apparatus of Claim 1 , wherein the magazining of the workpiece stacks is on a flat conveyor - compartmented or plain, or on a sequenced system of pallets, on which the workpiece stacks are repeatably positioned and which indexes the leading stack into a precise pickup position as required at the start of automatic operation, or subsequently as each stack is consumed, by means of electric motors or other known forms of actuation, under a control program which can interpret sensors mounted in salient positions to sense the depletion and correct arrival of each stack.

3. The apparatus of Claims 1 & 2, wherein the individual workpieces in each of the stacks, are sequentially picked up by an arrangement comprising a pair of fabric gripper/vertical axis modules mounted at each end of a shuttle carriage positioned to move across the axis of the stack to sequentially position each gripper above the stack, and which is controlled to operate in a cycle wherein each gripper picks up a workpiece from the top of the stack and moves it up and sideways to its respective fixed conveyor ( each positioned above and to each side of the feed stack ) for delivery, but wherein the operation of the two grippers is such that while one is picking up a workpiece, the other gripper is delivering the previous workpiece, in order to reduce the overall system cycle time.

4 The apparatus in Claims 1 & 3, wherein the separation of each workpiece as it is picked off the top of the stack is achieved by a mechanism which clamps down onto the top of the stack close to an edge, say in the case of a stack of fabric strips - the nose of a strip, with a friction drum, positioned on the stack and parallel to the edge, and when at each pickup, after the gripper has descended to sit upon the top of, and thus clamping the stack, the friction drum is rapidly rotated about its own axis half a turn anticlockwise then clockwise, to drag the edge of the top workpiece which is in contact with the drum, free of the remainder of the stack and flicking it out into a position sitting freely above the friction drum, so that it is completely free of the rest of the stack when it is picked up by the gripper, and yet the rest of the stack is still clamped by the friction drum ( which falls with the stack as it is consumed).

5. The apparatus in Claims 1 & 4, wherein the geometrically separated outputs of the pickup and separation mechanism feed alternately into two identically lengthed turnover chutes, which may be driven or passive, whose function is to respectively invert or maintain the face orientation of the workpiece, and where each takes a workpiece at its infeed position and delivers the workpiece at a near common outfeed position, by employing flat guide tunnels which in the inversion case achieves this by transporting the workpiece along a path which bends a right-handed 90 degrees angle in the plane of the flat guides, and in the non-inversion case bends a left-handed 90 degrees in the plane of the flat guides followed by a "U" turn in the plane at 90 degrees to the flat guides to re-invert the workpiece.

6. The apparatus in Claims 1 & 5, wherein the output of the turnover mechanism feeds into a processing module, such as a sewing machine or other workstation.