Easy to Fit-and-Fold Sheet with Zipper Fasteners

Abstract

A new design for fitted bed sheet coverings is described. This design has two major advantages over that of the prior art: (1) less work required to secure the sheet to the mattress; making this design ergonomically superior to the prior art, and (2) the advantage of having a sheet that folds flat for easy storage. The distinguishing feature of the design construction is the elimination of elastic and the introduction of four, tapered zipper fasteners. These fasteners secure the sheet to the mattress. The zipper fasteners are a unique two-component system that also represents a new design having wider application. Fitted bed sheets made from this design are of particular benefit for people with arthritis, people with poor manual dexterity, and children.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

Patent Application Ser. No. 14/284,907—An Easy-to-Secure, Easy-to-Fold Fitted Sheet

BACKGROUND OF THE INVENTION

The present invention, which for brevity will be called the Ezee Sheet, pertains to the art of fitted bed sheets in general, with particular application to large mattresses. Pertaining to the prior art: The construction of a fitted sheet involves cutting and sewing the material to conform to the shape of the mattress, and sewing elastic into the four sheet corners and the bottom seam. When stretched this elastic provides the tension which secures the bed covering to the mattress. This method of construction has not changed fundamentally since the fitted sheet was invented in 1959, U.S. Pat. No. 2,907,055. The prior art, as described here, are disclosed in the following U.S. Pat. Nos. 2,907,055, 4,962,546, 5,056,441, 5,127,115, 5,603,132, 4,672,702, 4,980,941, 5,029,353, 5,287,574, 6,618,880, and 6,842,921.

There are three problems associated with the prior art of fitted bed coverings, all three stemming from the inclusion of elastic in the design. These problems are: poor ergonomics, poor foldability, and a tendency to come off the mattress at various places around its base, what we will refer to as lift up. Poor ergonomics of the prior art is the result of having to stretch the elastic skirt around the perimeter of a mattress. As bed mattresses have become larger and heavier, this task has become more difficult, particularly for seniors and people with weak hands. Sometimes it proves necessary to lift up the corners of a heavy mattress in order to get the elastic under the corner. The angle from which this lifting is performed can result in injury to the back. A conventional fitted sheet can come off of the corners of the mattress as a result of lift up. It is also the elastic in the prior art that is the cause for not being able to flatly fold a conventional fitted sheet. So, as to avoid confusion, in all that follows, the terms, prior art and conventional sheet, shall be used interchangeably.

BRIEF SUMMARY OF INVENTION

The Ezee Sheet admits a new design for fitted bed sheet coverings. The goals of this design are: (1) to create a more ergonomic sheet; one that makes the task of putting a fitted sheet on a mattress much easier, (2) to construct a fitted sheet that is easy to fold; one that folds flat, and (3) to make a fitted sheet that resists lift up. The superiority of this design over the prior art is the result of simple physics.

There are two defining features of this invention: the elimination of elastic and the incorporation of four zipper fasteners for securing the sheet. By eliminating the elastic of the prior art, this design resolves the three problems associated with conventional sheets. The securing zipper fasteners are comprised of a tapered bands of stretch material into which a zipper is sewn. The ability for the zipper material to stretch provides the tension to secure the sheet to the mattress. The fasteners are located at the four corners of the sheet, and the zippers are pulled top to bottom to secure the sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an angled view of the sheet design and one of the corner zipper fasteners.

FIG. 2 depicts a planar view of the sheet with general dimensions. Lines delineating zipper fasteners have been hidden in this figure.

FIG. 3 depicts the meaning of x in FIG. 2.

FIG. 4 depicts the two-component zipper fastener.

FIG. 5 depicts the fastener in more detail and where it is sewn into the sheet material.

FIG. 6 depicts a view of one sheet corner with a closed zipper fastener.

DETAILED DESCRIPTION OF THE INVENTION

The Ezee Sheet represents a new art in the design and construction of fitted bed sheets. What distinguishes this invention from conventional sheets is the manner in which it is secured to the mattress. A conventional sheet incorporates elastic in its bottom seam, and it is this elastic, when stretched, that secures the sheet to the mattress. It is also this elastic that results in the three problems discussed in [0002]. This new design eliminates the elastic and incorporates four specially designed zipper fasteners to secure the sheet.

The Ezee Sheet is constructed of two components, the sheeting material and the zipper fasteners. The sheeting material can be cut from a single piece of material or it can be constructed from multiple pieces sewn together at various seams. A partial angled view of the sheet with placement of one of the corner zipper fasteners is depicted in FIG. 1. FIG. 2 depicts a planar view of the geometry. For clarity the zipper fasteners are not shown in FIG. 2. The sheet can be described as having two non-rectangular side panels (1), two non-rectangular end panels (2), and a top rectangular panel (3). Because there is no elastic sewn into any seam, this is how the sheet would appear if laid out flat on a floor. The top panel dimensions equal those of the mattress: L defines its length, W defines its width, and D defines its depth. The lengths of the bottom edges of the side and end panels are shorter than their top edges by an amount, 2x. This difference in length is reflected in the tapered design of the zipper fastener, and admits a secure fit when the zippers on the fasteners are pulled downward. The meaning of x is rendered in FIG. 3.

The zipper fastener is the second component of the Ezee Sheet design. This fastener is comprised of a zipper sewn into a contiguous piece of stretchable material. The geometry of the fastener is depicted in FIG. 4. In this figure the zipper is 4 and the stretch material is 5. The material can be any suitable stretch material; for this discussion we will assume it is spandex. The spandex is tapered; it is narrower at the top than it is at the bottom. These dimensions are shown respectively in FIG. 4 as A and B, and A is shorter than B. One arm of the spandex is sewn into an side panel and the other side is sewn into the adjacent end panel. The top of the spandex is sewn into the top panel of the sheet. This is depicted in FIG. 5. In this figure the dotted line (6) represents the edges of side panel 1. Note that the adjacent end and side panels of the sheet material are tapered to conform to the taper of the fastener. As the zipper is pulled downward the spandex stretches, increasing the tension in this material. Because the spandex is tapered, the further the zipper is pulled down, the greater is the tension. This increased tension is what secures the sheet to the mattress. Note that this is controlled by the choice one makes for the dimension, x, in FIG. 3. If the tops and bottoms of the adjacent side and end panels were not tapered (x=0), the tension would be zero, and the sheet would not be as secure. This makes the tapered zippered unique to this art.

This Ezee Sheet design is ergonomically superior to that of the prior art. Ergonomics is based upon efficiency of motion and the physical concept of “work”. Apply a force to an object and move the object a certain distance, and you are doing work on that object. To stretch the elastic of a conventional fitted sheet requires that work be done on the elastic. The bigger the mattress, the more work one has to do in order to secure a conventional sheet to the mattress. This design employs zippers to secure the sheet, and the action of pulling down four zippers entails less work than the action of stretching elastic around a mattress bottom. Also, the work done in pulling down the four zippers increases only modestly with mattress size, depending only upon the mattress depth. Reducing the work required to secure a fitted sheet to a mattress is a distinct ergonomic advantage of this design over that of the prior art.

The Ezee Sheet has superior foldability to that of the prior art. This is a result of removing the elastic from the design. This is common sense, but the underlying reason for doing this is based upon physical principles. Stretch a rubber band and you put it under tension. Let it go and the rubber band springs back to its “relaxed” state. The same principle is at work when you remove a conventional fitted sheet from a mattress. The elastic, which is part of the sheet system, assumes its relaxed state. The result is a sheet that cannot be folded flat. Remove the elastic from the design and this is no longer a problem; the Ezee Sheet folds flat, and stores easily.

The Ezee Sheet resists the tendency to lift up at different locations around the mattress bottom because it has no elastic in the bottom seam. The problem of lift up in the prior art is caused by the tension that develops in elastic band when it is stretched. If there is a disturbance of the elastic at some location a force imbalance will occur, and the sheet will respond in such a way as to reduce this tension. If the disturbance is located at a mattress corner the sheet may come off at this location. By removing the elastic in the new design, this unstable situation is removed, thus remedying lift up.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a partial view for the design: Adjacent end and side panels are respectively numbered 1 and 2, and the top surface of the sheet is 3. The two-component zipper fastener is comprised of a zipper, 4, and a contiguous piece of stretchable material, 5, into which the zipper is sewn.

FIG. 2 depicts a top view of the sheet, with the lines delineating the zipper fastener not represented. The sheet dimensions equal the dimensions of the mattress: L is the mattress length, W is its width, and D is its depth. The lengths of the bottom edges of the side and end panels are shorter than their top edges by an amount, 2x.

FIG. 3 depicts in planar view a blowup view of one corner. This indicates how x is measured.

FIG. 4 depicts a zipper fastener, as it would appear when laid flat. The zipper, 4, is sewn into a contiguous piece of tapered, stretchable material, 5. The taper is shown as going from length A to length B, with A<B.

FIG. 5 depicts one half of the zipper fastener and an end section of the side panel, 1. The dotted line refers to the edges of this panel, with the arrow directed at where this panel would be sewn into the elastic part of the fastener. The other side of the fastener is sewn into the adjacent end panel (not shown).

FIG. 6 depicts one corner of the design, in which the zipper is fully closed, having pulled together the two adjacent panels to provide a secure fit to the mattress.

Claims

1. A fitted sheet

having a rectangular top panel, two non-rectangular side panels, and two nonrectangular end panels,

constructed from a single piece of fabric or multiple pieces stitched together,

constructed with no elastic band,

secured to the mattress using four tapered zipper fasteners.

2. A tapered zipper fastener having multiple applications.