Method of symmetrically locating a pattern piece relative to work material having a variable repeat pattern

#The present invention generally relates to positioning pattern pieces on sheet-type work material, and more particularly, is directed to a method for aligning a pattern piece relative to a work material defining a variable repeat pattern, so that end portions of the pattern piece are positioned symmetrically with respect to the pattern.

#During the mass production of articles made from sheet-type work material, such as fabric, one or more layers of fabric are typically spread onto what is referred to by those skilled in the art of fabric processing as a spreading table. The fabric is then moved, often via a conveyor, onto a support surface forming part of a work material processing apparatus like a cloth cutting machine. A cloth cutting machine can be used to cut the fabric into pattern pieces for use in garments, furniture or other articles.

#Generally, the pattern pieces are positioned on the spread fabric in a spatial array of segments positioned in a cutting sequence. This spatial array of segments is referred to by those skilled in the art as a “marker.” Usually markers are computer generated to optimize piece pattern density and thereby minimize the waste of fabric.

#FIG. 1 is a perspective view of a cloth cutting apparatus having a layer of sheet-type work material defining a pattern thereon positioned on a cutting table.

#FIG. 2 is a schematic representation of an image of a pattern piece positioned relative to a work material wherein end portions of the pattern piece are not symmetrically aligned with a pattern defined by the work material.

#FIG. 3 is a schematic representation of the location of first and second images of respective end portions of the pattern piece of FIG. 2.

#Referring to FIG. 1, a sheet-type work material processing apparatus generally designated by the reference number 10 and depicted in the illustrated embodiment as a cloth cutting machine, defines a frame 12 having a support surface 14 carried thereon. The cutting machine 10 also includes a beam 16 extending transversely across the support surface 14 and moveable back and forth in a longitudinal direction thereof in response to command signals generated and issued by a controller 18 in communication with a cutting apparatus. A cutting head 20 having a cutting tool 22 such as a reciprocating blade is mounted to the beam 16 for movement longitudinally thereof also in response to command signals generated and issued by the controller 18. A camera 24 is attached to the cutting head 20 and moves with the cutting head for capturing images of a layer of sheet-type work material 26 defining a pattern 28 thereon. In the illustrated embodiment, the pattern 28 is a striped pattern with varying repeat dimensions, such that the distance between each stripe may not be uniform.

#A display 30 shown in the illustrated embodiment as a computer type monitor is in communication with the controller 18 as is the camera 24. While the controller 18 has been shown in the illustrated embodiment as a PC type computer, the present invention is not limited in this regard as any type of controller capable of being programmed to receive signals from a camera, or sensors in general, and to send an image received to a display such as a programmable logic controller can be substituted without departing from the broader aspects of the present invention. In addition, while a computer type monitor has been shown and described in the illustrated embodiment the present invention is also not limited in this regard, as any type of display device capable of displaying an image of areal portions of the spread work material 26 can be substituted without departing from the broader aspects of the present invention.

#The controller 18 is programmed to operate the beam 16 and the cutter head 20 to move them across the surface of the work material 26 carried by the support surface 14 so as to carry out both image capturing and cutting operations. In addition, the controller is programmed for receiving marker signals corresponding to an array of pattern pieces 34–36 located with respect to the work material 26. These marker signals further including reference signals corresponding to reference points identified on the pattern pieces. The controller is also provided with further information corresponding to the marker to be registered with the work material 26 positioned on the support surface 14 and the pattern 28 defined thereon, as well as for analyzing images received from the camera 24.