Heat shrinkable fabric panels for facilitating seat cover installation

Methods and apparatus for form-fitting covers to vehicle passenger seats are provided. A cushion is mounted on a seat frame and surrounded by a cover having one or more heat shrinkable fabric panels attached to a peripheral edge thereof. Each heat shrinkable fabric panel is attached to the seat frame and heat is applied. The heat causes each panel to shrink along a predetermined direction, thereby drawing the cover taut around the cushion and frame.

FIELD OF THE INVENTION
 The present invention relates generally to passenger vehicle seats and,
 more particularly, to seat covers for passenger vehicle seats.
 BACKGROUND OF THE INVENTION
 During the production of automotive interiors, particularly seats, fabric
 that is to serve as a seat cover is typically stretched over a cushion and
 frame and secured thereto (i.e., the fabric is "form-fitted" to the seat
 cushion and frame). Conventional processes for form-fitting fabric covers
 to seat cushions and frames may involve manually pulling and stretching a
 cover to eliminate wrinkles while, at the same time, attaching the cover
 to the frame. Unfortunately, manual form-fitting processes may be somewhat
 labor intensive and, thus, costly. Because vehicle manufacturers are
 continuously looking for ways to reduce vehicle manufacturing and assembly
 costs, it would be desirable to provide lower cost methods of form fitting
 covers to passenger seats.
 SUMMARY OF THE INVENTION
 In view of the above discussion, the present invention provides methods and
 apparatus for form-fitting covers to passenger seats. A cushion is mounted
 on a seat frame and surrounded by a cover having one or more heat
 shrinkable fabric panels attached to a peripheral edge thereof. Each heat
 shrinkable fabric panel is attached to the seat frame and heat is applied.
 The heat causes each panel to shrink along a predetermined direction,
 thereby drawing the cover taut around the cushion and frame.
 Each heat shrinkable fabric panel includes a plurality of partly-oriented
 yarn (POY) strands aligned in a first direction and a plurality of
 fully-oriented-yarn (FOY) strands aligned a second direction transverse to
 the first direction. The POY strands are configured to shrink between
 about ten percent and sixty percent (10%-60%) of an unheated length when
 heat is applied thereto. The FOY strands are configured to resist
 shrinking. Accordingly, each heat shrinkable fabric panel is configured to
 shrink along the direction of orientation of the POY strands.
 An important advantage of the present invention is that the process of
 manually form-fitting covers to passenger seats may be eliminated. As
 such, fabrication and assembly costs may be reduced.

DETAILED DESCRIPTION OF THE INVENTION
 The present invention now will be described more fully hereinafter with
 reference to the accompanying drawings, in which preferred embodiments of
 the invention are shown. This invention may, however, be embodied in many
 different forms and should not be construed as limited to the embodiments
 set forth herein; rather, these embodiments are provided so that this
 disclosure will be thorough and complete, and will fully convey the scope
 of the invention to those skilled in the art. Like numbers refer to like
 elements throughout the description of the drawings.
 Referring now to FIG. 1, a conventional passenger seat 10 for a vehicle is
 illustrated. The illustrated passenger seat 10 includes a seat portion 11
 and a back rest portion 12. As illustrated in FIG. 2, the seat portion 11
 includes a contoured cushion 13 attached to a frame 14 and surrounded by a
 cover 15. The contoured cushion 13 is supported by the frame 14 via a
 plurality of springs 16 extending within the frame 14, as is known to
 those of skill in the art. The cover 15 is fabric that has been pulled
 tight (i.e., "form-fitted") around the contoured cushion 13 and secured to
 the frame 14.
 Referring now to FIGS. 3 and 4, a seat 30 incorporating elongated panels 40
 formed from heat shrinkable fabric, according to the present invention, is
 illustrated. The illustrated seat 30 includes a frame 35, a plurality of
 springs 36 extending within the frame 35, a contoured, resilient cushion
 37 mounted on the frame 35 and supported by the springs 36, and a cover 38
 form-fitted to the contoured, resilient cushion 37. The contoured,
 resilient cushion 37 includes front, back, and side surfaces 37a, 37b,
 37c, respectively. The cover 38 surrounds the front surface 37a and each
 side surface 37c of the contoured, resilient cushion 37 and includes a
 peripheral edge portion 39. In the illustrated embodiment, four elongated
 panels 40 formed from heat shrinkable fabric are utilized to attach the
 cover 38 to the frame 35.
 In the illustrated embodiment, each elongated panel 40 includes opposite
 first and second edge portions 40a, 40b. A widthwise direction (indicated
 as W) for each elongated panel 40 is defined by a line extending from a
 respective first edge portion 40a to a respective second edge portion 40b
 for each panel 40. The first edge portion 40a of each elongated panel 40
 is attached to the peripheral edge portion 39 of the cover 38. The second
 edge portion 40b of each elongated panel 40 is attached to the frame 35.
 Each elongated panel 40 may be attached to the cover peripheral edge
 portion 39 in various ways including, but not limited to, stitching and
 adhesives. Each elongated panel 40 may be attached to the frame 35 in
 various ways including, but not limited to the use of fasteners and
 adhesives.
 Each elongated panel 40 is woven from yarn configured to shrink along the
 respective widthwise direction W when heat is applied thereto. Thus, in
 the presence of heat, each elongated panel 40 shrinks along its widthwise
 direction W to draw the peripheral edge portion 39 of the cover 38 towards
 the frame 35, thus pulling the cover 38 taut around the contoured,
 resilient cushion 37.
 Referring now to FIG. 5, an enlarged plan view of a weave pattern 50 of
 heat shrinkable fabric according to a preferred embodiment of the present
 invention is illustrated. The illustrated weave pattern 50 includes
 partly-oriented yarn (POY) strands 52 extending along a first direction
 L.sub.1 (i.e., the longitudinal direction of each POY strand), and
 fully-oriented-yarn (FOY) strands 54 extending along a second direction
 L.sub.2 transverse to the first direction L.sub.1. When heated, the POY
 strands 52 shrink along their longitudinal direction (i.e., along
 direction L.sub.1). Preferably, each POY strand 52 is configured to shrink
 along the first direction L.sub.1 between about ten percent and sixty
 percent (10%-60%) of an unheated length when heat is applied thereto.
 Preferably, each FOY strand 54 is configured to resist shrinkage along
 direction L.sub.2 when heat is applied thereto, or shrink by no more than
 about three to six percent (3%-6%).
 Each POY strand 52 preferably is formed from yarn filaments in which the
 draw ratio is less than normal resulting in only partial longitudinal
 orientation of the polymer molecules. Each FOY strand 54 preferably is
 formed from yarn filaments in which the polymer molecules have full
 longitudinal orientation. POY strands and FOY strands and there formation
 are understood by those of skill in the art and need not be discussed
 further herein.
 Exemplary fibers out of which POY strands 52 and FOY strands 54 may be
 formed include polyvinyl chloride, polyethylene, polystyrene, and
 polyester. However, it is understood that, for practicing the present
 invention, there may be used any kind of fabric, provided that is knit
 from fibers which are thermally shrinkable in a lengthwise direction of
 the fibers without losing their original, fundamental properties.
 Referring now to FIG. 6, operations for form-fitting covers around
 passenger vehicle seats, according to the present invention, are
 illustrated. A cushion is mounted on a seat frame (Block 100) and
 surrounded by a cover having one or more heat shrinkable fabric panels
 attached to a peripheral edge of the cover (Block 110). As described
 above, each heat shrinkable fabric panel includes a plurality of
 partly-oriented yarn (POY) strands in a first direction and a plurality of
 fully-oriented-yarn (FOY) strands in a second direction transverse to the
 first direction. The POY strands are configured to shrink between about
 ten percent and sixty percent (10%-60%) of an unheated length when heat is
 applied thereto. Each heat shrinkable fabric panel is then attached to the
 frame (Block 120). Heat is then applied to each heat shrinkable fabric
 panel causing each panel to shrink along a predetermined direction,
 thereby drawing the cover taut around the cushion and frame (Block 130).
 Heat may be applied via conventional methods including, but not limited to,
 infrared lamps, hot air, steam, and the like. In addition, a seat assembly
 (i.e., the cushion, frame and cover) may be passed through a heat
 generating source to apply heat to each of the heat shrinkable fabric
 panels.
 The foregoing is illustrative of the present invention and is not to be
 construed as limiting thereof. Although a few exemplary embodiments of
 this invention have been described, those skilled in the art will readily
 appreciate that many modifications are possible in the exemplary
 embodiments without materially departing from the novel teachings and
 advantages of this invention. Accordingly, all such modifications are
 intended to be included within the scope of this invention as defined in
 the claims. Therefore, it is to be understood that the foregoing is
 illustrative of the present invention and is not to be construed as
 limited to the specific embodiments disclosed, and that modifications to
 the disclosed embodiments, as well as other embodiments, are intended to
 be included within the scope of the appended claims. The invention is
 defined by the following claims, with equivalents of the claims to be
 included therein.