System for capturing stretched fabrics in carrier frames

Details System for capturing stretched fabrics in carrier frames System for capturing stretched fabrics in carrier frames

2000-09-12

2001-12-11

Davis, Robert (Department: 1722)

Plastic article or earthenware shaping or treating: apparatus

Distinct means to feed, support or manipulate preform stock...

And means to apply stress to preform and uniting in stressed...

C264S252000, C425S122000, C425S292000

Reexamination Certificate

active

06328548

ABSTRACT:

BACKGROUND OF THE INVENTION
The invention relates generally to capturing support materials in carrier frames, and more particularly to insert molding support materials in carrier frames, useable in the manufacture of seat and seat back components.
Many manufacturing operations include the molding of a support material in a rigid or non-rigid frame. In the manufacture of seat and seat back components, for example, a stretched elastic material, or fabric, is insert molded in a non-rigid plastic carrier frame. The non-rigid carrier frame and stretched fabric captured thereby is then mounted in a recess of a relatively rigid seat or seat back member of a chair, thereby providing very comfortable seat and back support.
Known prior art systems and methods for insert molding stretched elastic fabrics in plastic carrier frames are performed by complex machinery, and also require substantial participation by a human operator. The productivity of these known operations is costly and limited by the relatively poor machinery reliability and high maintenance requirements, and by operator inefficiency and inconsistencies.
In the known prior art process flow diagram of
FIG. 6
, a pre-cut stretchable elastic fabric blank is placed manually in a fabric stretcher, illustrated in block
1
, which is actuatable pneumatically or by other automated means to stretch the fabric, usually in two dimensions. As with any prolonged activity, however, repetitive placement of the fabric blanks in the fabric stretcher and the handling thereof generally without resting periodically may subject the operator to mental and physical fatigue, which adversely affects productivity. Also, production usually ceases during operator rest periods unless an alternate operator is available to resume production.
In the prior art process flow diagram of
FIG. 6
, the stretched fabric is locked in a loom, illustrated in block
2
, between mating frame-like members, which are manually clamped together from opposing sides of the fabric blank, before the stretched fabric is released from the fabric stretcher, illustrated in block
3
. The locked loom and the stretched fabric retained thereby are then transported along a conveyor to a mold press, illustrated in block
4
, where the loom is aligned and retained for the molding operation. More particularly, the mold press closes on the loom and the stretched fabric before the carrier frame is molded from a plastic or other known material suitable for use in molding operations so that the stretched fabric is captured and retained by the molded carrier frame, as illustrated in block
5
.
One known stretchable elastic material suitable for the manufacture of seats and seat back components includes woven fibers, for example LYCRA fibers. The weave of some fabric materials however has a visible weave pattern, and thus it is desirable aesthetically that the weave pattern be aligned properly in the assembled chair. It is important therefore that the fabric blank be aligned accurately when placed initially in the fabric stretcher and that the loom be aligned accurately thereabout, since a misaligned weave pattern will render the molded carrier frame unacceptable for use in the final chair assembly. To facilitate the alignment procedure and to reduce waste, it is necessary to provide a fabric alignment apparatus. The alignment apparatus however is costly and does not ensure accurate alignment, which depends ultimately on the skill and attentiveness of the operator.
In
FIG. 6
, after the molding operation, the locked loom retaining the stretched fabric and the molded carrier frame are returned along the conveyor back toward the fabric stretcher, illustrated in block
6
, where the loom is unlocked manually to release the molded carrier frame and the stretched fabric portion captured thereby, as illustrated in block
7
. The handling of the loom is performed manually, which slows productivity. Also, the operator often stands idle during the molding operation and while the loom is transported to and returned from the mold press, since additional looms may not be conveyed to the mold press along the conveyor until the previously conveyed loom is returned therefrom. This prior art production arrangement is inefficient for its limited throughput, and for its dependency on substantial participation by the operator.
In
FIG. 6
, after a sufficient cool down period and upon removal of the carrier frame from the loom, excess bulk fabric is removed partially from around the carrier frame by the operator in a rough cutting operation performed manually with automated shears or a heated knife, as illustrated in block
8
. The performance of the rough cutting operation however is complicated by the tendency of the non-rigid carrier frame to collapse and twist under the tension of the constricting elastic fabric upon removal thereof from the loom. After the rough cutting operation, the carrier frame is placed manually in an automated trimming machine that removes excess fabric and any mold flash from the outer perimeter, or outer edge portion, of the carrier frame, as illustrated in block
9
.
It is important that the carrier frame be trimmed completely and precisely, particularly the inner and outer edge portions thereof, since the carrier frame and the stretched fabric captured thereby are largely visible in the finished article. And although the automated trimming operation is relatively precise, the trimmed carrier frame is subsequently subject to a manual trimming operation, illustrated in block
10
, to remove any mold flash from the inner edge portion of the carrier frame and to manually spot trim outer edge portions thereof not trimmed completely in the automated trimming operation. The rough cutting and multiple trimming operations are time consuming and extremely laborious, thus imposing substantial limitations on production and increasing costs. Additionally, any improper cutting or trimming will render the carrier frame unacceptable for use in the final assembly, and is ultimately wasteful since the carrier frame and captured support material are not recyclable.
The present invention is drawn toward advancements in the art of capturing support materials in carrier frames, useable for example in the manufacture of seat and seat back components and for many other applications.
It is an object of the present invention to provide novel methods and systems for capturing support materials, including stretchable elastic fabrics and plastics, in carrier frames that are economical and that overcome one or more problems in the art.
It is another object of the invention to provide novel methods and systems for capturing support materials in carrier frames having generally one or more advantages over the prior art, including improved productivity, reduced dependency on high maintenance and unreliable machinery, reduced dependency on manual operations, eliminating manually handling looms, improved weave pattern alignment accuracy, improved production throughput, and elimination of one or more cutting and/or trimming operations.
It is another object of the invention to provide novel methods and systems for capturing support materials in carrier frames that substantially reduce manually handling of the support material, including reducing Or eliminating repetitive manual placement of the support material on a conveyor, and in some applications placement of the support material in a support material stretcher.
It is a more particular object of the invention to provide novel methods and systems for capturing support materials in carrier frames, useable in the manufacture of seat and seat back components, comprising generally moving the support material, either continuously or as discrete elements, to an openable mold press, the mold press forming a mold cavity for the carrier frame when the mold press is closed, shaping the support material, and molding the carrier frame after shaping the support material to capture the shaped support material in the carrier frame.
It is another more particular object of the

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