Geometrical instruments – Gauge – Center – point – distance between centers – or centerline location
Reexamination Certificate
1998-08-17
2001-04-17
Noland, Thomas P. (Department: 2856)
Geometrical instruments
Gauge
Center, point, distance between centers, or centerline location
C073S159000, C700S134000, C702S150000
Reexamination Certificate
active
06216353
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates generally to cutting systems for cutting a garment pattern from a tubular knit fabric lay and, more particularly, to a centerline detector for a tubular knit fabric lay cutter.
(2) Description of the Prior Art
Fabric cutting is typically performed on a multiplicity of fabric layers referred to as fabric plies. The multiplicity of fabric plies are vertically arranged to form a fabric lay which is moved into a cutting assembly for cutting the plies simultaneously according to a predetermined arrangement of fabric sections which may have varying size and shape.
Generally, the vertical arrangement of fabric plies produces a fabric lay with nonuniform edge alignment which results in fabric waste or nonuniform cut fabric sections. More particularly, for tubular knit fabric lays, the amount of edge waste and/or the number and probability of non-uniform cut fabric sections involving the folded edges is substantially increased.
Various prior art fabric cutting systems have attempted to measure and control the fabric longitudinal centerline with respect to the cutter in order to decrease the amount of edge waste due to nonuniform edge alignment within the fabric lays. Although the prior art has sought to decrease fabric waste due to section cut layout inefficiency via automated cutting systems which optimize section layout within a given fabric length, such prior art systems have relied upon manual measurement of the fabric edges and calculation of the fabric lay centerline therefrom, generally by interpolation between two points measured at predetermined fabric intervals. Fabric cutting patterns were then readjusted based upon those centerline values.
Fabric lay centerline points determined from prior art manual measurements of the nonuniform edges have typically produced centerline error in the range of +/−6 mm within a given fabric length. Particularly for tubular knit fabric lays where fabric sections are cut around the folded edges, fabric lay centerline measurement error is substantially increased because the amount of waste is magnified by at least a power of two for the edge cut sections. When, rarely, cuts are made with respect to both folds, the effect of the error increases to four times! Thus, 5 mm error on both folds of a matching front and back garment piece could result in a 20 mm error in the seam location. This error would be sufficient to produce a second quality, low profit garment.
One prior art alternative to centerline calculation involved fabric lay alignment along one edge of the fabric lay. While this method reduces the need for highly accurate centerline measurements, a substantial amount of waste is still produced along the nonaligned edge. For tubular knitted fabrics, further waste results because fabric section cutting may not be optimized without use of both folded edges.
Thus, there remains a need for a fabric lay centerline detector for automatically measuring and determining the centerline of a fabric lay, particularly for tubular knit fabric lays, whereby the centerline determination error is substantially reduced thereby decreasing fabric waste and folded edge cut section non-uniformity while, at the same time, can make an accurate measurement even when the fabric lay is covered by a plastic vacuum film.
SUMMARY OF THE INVENTION
The present invention is directed to a centerline detector for a tubular knit fabric lay cutter table. The apparatus includes a nearside side edge compressor for determining the position of the nearside edge of the fabric lay and providing a signal representative of the nearside edge. In the preferred embodiment the nearside compressor includes a first generally vertical movable paddle and an actuator for moving the first paddle against the nearside edge of the fabric lay at a predetermined pressure.
The apparatus also includes a farside side edge compressor for determining the position of the farside edge of the fabric lay and providing a signal representative of the farside edge. In the preferred embodiment, the farside compressor includes a second generally vertical movable paddle and an actuator for moving the second paddle against the farside edge of the fabric lay at substantially the same predetermined pressure as the first paddle.
A controller is connected to the nearside side edge compressor and the farside side edge compressor for receiving the signal representative of the nearside edge and the signal representative of the farside edge and calculating a first centerpoint of the fabric lay. In the preferred embodiment the centerline detector makes at least two measurements along a length of the fabric lay. The multiple measurements of the centerpoint of the fabric lay can then be used to calculate the centerline of the fabric lay between the two points as well as the centerline angle with respect to the edge of the cutter table. This information can be used by the cutter table to adjust the layout of the fabric garment pieces that the cutter will be used to cut.
Finally, in the preferred embodiment, a plastic film tucker upstream from the centerline detector tucks the edges of the plastic film against the nearside edge and the farside edge of the fabric lay to prevent interference with the operation of the centerline detector. The plastic film is generally placed over the fabric lay and a vacuum is applied prior to cutting since the combination of the plastic film and vacuum stabilizes the package and permits faster and more accurate cutting. However, the edges of the plastic film may “tent” adjacent to the edges of the fabric lay and, on occasion, interfere with the operation of the centerline detector. The tucker prevents the “tent” from forming.
Accordingly, one aspect of the present invention is to provide a centerline detector for a tubular knit fabric lay cutter table. The apparatus includes: (a) a nearside side edge compressor for determining the position of the nearside edge of the fabric lay and providing a signal representative of the nearside edge; (b) a farside side edge compressor for determining the position of the farside edge of the fabric lay and providing a signal representative of the farside edge; and (c) a controller connected to the nearside side edge compressor and the farside side edge compressor for receiving the signal representative of the nearside edge and the signal representative of the farside edge and calculating a first centerpoint of the fabric lay.
Another aspect of the present invention is to provide a centerline detector for a tubular knit fabric lay cutter table. The apparatus includes: (a) a nearside side edge compressor for determining the position of the nearside edge of the fabric lay and providing a signal representative of the nearside edge, the nearside compressor including a first generally vertical movable paddle and an actuator for moving the first paddle against the nearside edge of the fabric lay at a predetermined pressure; (b) a farside side edge compressor for determining the position of the farside edge of the fabric lay and providing a signal representative of the farside edge, the farside compressor including a second generally vertical movable paddle and an actuator for moving the second paddle against the farside edge of the fabric lay at substantially the same predetermined pressure as the first paddle; and (c) a controller connected to the nearside side edge compressor and the farside side edge compressor for receiving the signal representative of the nearside edge and the signal representative of the farside edge and calculating a first centerpoint of the fabric lay.
Still another aspect of the present invention is to provide a centerline detector for a tubular knit fabric lay cutter table. The apparatus includes: (a) a nearside side edge compressor for determining the position of the nearside edge of the fabric lay and providing a signal representative of the nearside edge, the nearside compressor including a first generally vertical movable paddle and an ac
Noland Thomas P.
Rhodes & Mason PLLC
Sara Lee Corporation
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