1. Field of the Invention
This invention relates to a fitted mattress cover that has a woven or knitted skirt. More particularly, the invention concerns a process for making such a fitted mattress cover, wherein the woven or knitted skirt fabric has an edge comprising strong elastic yarns that are woven or knit integrally with the skirt fabric. The elastic yarns of the edge form a band that provides sufficient tension to pull the skirt material under the mattress when the mattress cover is fit onto a mattress.
2. Description of the Prior Art
Fitted mattress covers comprise a flat top panel of substantially inextensible material and a skirt that depends from the periphery of the top panel. In use, the top panel covers the top of surface of the mattress and the skirt covers the sides of the mattress. Mattresses to which the covers are fitted typically have a thickness in the range of about 7 to about 15 inches. As used herein, the term "longitudinal direction" refers to the direction that follows around the long dimension of the sides of a mattress and the term "transverse direction" refers to the direction that is perpendicular to the longitudinal direction and is parallel to the thickness dimension of the mattress.
Known fitted mattress covers have often included skirts that had specially constructed corners or an elastic tape attached to the bottom edge of the skirt, to help hold the fitted mattress cover in place. For example, May, U.S. Pat. No. 2,942,280, disclosed a fitted mattress cover having an inwardly sloping skirt made of a cotton fabric commonly used in undergarments, the end and side walls of the skirt being connected at each corner to form progressively tapered corners, and the bottom edge of one end wall containing an attached elastic tape. Other early fitted mattress covers were disclosed by Anderson et al, U.S. Pat. No. 3,237,175, column 1, lines 15-37, which disclosure is incorporated herein by reference. Anderson et al also disclosed elastic tapes enclosed within a folded and stitched entire bottom edge of the skirt of a fitted mattress cover.
Each of the early fitted mattress covers had skirts that lacked substantial elastic retractive power in the longitudinal direction of the skirt. As a result, the skirts seldom had a neat, snug fit on the mattress. Furthermore, the elastic tapes had to be manufactured separately and then sewn in or otherwise attached to the skirt edge.
To overcome some of these shortcomings, particularly the lack of longitudinal elastic retractive power, various fitted mattress covers having stretchable skirts of stitchbonded fabrics have been suggested. Some such stitchbonded fabric skirts have substantial elastic stretchability and retractive power in the longitudinal direction, as well as some stretchability in the transverse direction. Mattress covers with skirts having transverse stretchability accommodate the different thicknesses of commercial mattresses. For example, Williams et al, U.S. Pat. No. 5,127,115, discloses a mattress cover that has a stitchbonded fabric skirt that is stretchable in the longitudinal and transverse directions, and has an elastic band attached to the bottom edge of the skirt fabric Zafiroglu, the present inventor, in U.S. Pat. Nos. 5,187,952 and 5,247,893, discloses a fitted mattress cover having an elastic skirt formed from a stitchbonded fabric comprising a substantially nonbonded fibrous layer in which elastic yarns, such as spandex elastomeric yarns, are stitched to create lanes of different longitudinal stretchability and equal transverse stretchability. A heavy elastic band is attached to the bottom edge of the skirt fabric. Zafiroglu et al, U.S. Pat. No. 5,636,393, discloses another fitted mattress cover having another stitchbonded fabric skirt that has a greater stretchability in the transverse direction than in the longitudinal direction. Zafiroglu, U.S. Pat. No. 5,603,132, discloses still another fitted mattress cover having another stitchbonded skirt that does not have a banded appearance. Although fitted mattress covers with such stitchbonded fabric skirts have met with some success in the bedding market, further improvements are desired. The present inventor has found that some mattress covers made with skirts of stitchbonded fabrics that incorporate nonwoven layers of substantially non-bonded or non-entangled fibers, sometimes are prone to mechanical failure and to pilling, especially when the covers are laundered. The present inventor also found that mattress covers made with skirts of stitchbonded fabrics that incorporate nonwoven layers of strongly bonded or highly entangled fibers, though stronger and less prone to pilling, usually do not have sufficient flexibility or softness desired for the skirt fabric.
An aim of the present invention is to provide a fitted mattress cover having a skirt which can be fitted neatly and snugly onto mattresses of different thicknesses, can retain its desirable characteristics even after several launderings and does not suffer the shortcomings of mattress covers made with skirts of stitchbonded fabrics.
Another aim of the present invention is to provide an economical process for making a fitted mattress cover wherein the skirt fabric has an elastic edge formed integrally within the skirt during the knitting or weaving of the skirt.