EP1236846A2

EP1236846A2 - Swimming pool cover having reduced friction during slidable movement

Info

Publication number: EP1236846A2
Application number: EP01110841A
Authority: EP
Inventors: Harry J. Last; Keith J. Martin; David Dunn
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-02-28
Filing date: 2001-05-04
Publication date: 2002-09-04
Anticipated expiration: 2021-05-04
Also published as: EP1236846A3; DE60121418D1; EP1236846B1; US20020116756A1; ATE333021T1

Abstract

A swimming pool cover for extension over and retraction from a swimming pool and where the cover may engage a portion of the deck surrounding the swimming pool during movement thereof. The swimming pool cover comprises a flexible fabric sheet of the type capable of being spooled or rolled and capable of being unrolled to extend over a swimming pool. The swimming pool cover is comprised of a sheet having a top surface and a bottom surface with the bottom surface extending over and potentially in contact with the upper surface of the water in the swimming pool. In order to reduce frictional effects between the bottom surface of the swimming pool cover and the upper surface of the deck, the swimming pool cover is provided with a surface configuration which is roughened to substantially reduce surface area contact of the sheet with the deck of the swimming pool. In this way, frictional effects between the cover and the deck are reduced during movement thereof. The bottom surface configuration may adopt any of a variety of forms, including ribs formed on the bottom surface of the sheet, a mesh screen-like substrate secured to the bottom surface of the sheet, or a plurality of projections similar to those of an artificial turf secured to the bottom surface of the sheet, etc.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates in general to certain new and useful improvements in swimming pool covers and, more particularly, to an improved swimming pool cover which is provided with a surface configuration on its underside to reduce frictional effects between the swimming pool cover and a surface with which the cover is in contact.

2. Brief Description of the Related Art

Generally, all presently available automatic swimming pool covers consist of a fabric sheet, usually formed of a vinyl material, and slidably secured at the sides of the swimming pool in tracks. Automatic pool cover systems are illustrated and described in U.S. Patent No. 3,060,455 to Joe H. Lamb, U.S. Patent No. 4,001,900 to Joe H. Lamb, U.S. Patent No. 4,464,801 to Joe H. Lamb, U.S. Patent No. 4,939,798 to Harry J. Last, U.S. Patent No. 3,277,498 to Myron Kleinbard, et al, as well as numerous others. In all automatic swimming pool cover systems, it is necessary for a portion of that swimming pool cover, at least at longitudinal edges of the cover, for example, to engage the pool deck as the cover moves back and forth across the swimming pool. This is due to the fact that the tracks which support the edges of the cover are necessarily spaced slightly away from the body of water. In this case, approximately ninety-five percent of the pool cover floats on the pool water surface when moved thereacross.
It has also recently been recognized that one of the ways to overcome this problem of excessive friction between the pool deck and the fabric cover is to utilize a roughened surface on the deck. For example, an artificial turf of the type used in sports fields and the like can be placed on the deck surface in order to reduce surface area contact between the artificial turf and the cover. Other types of carpet-like materials which will serve to break up the surface tension of the water and reduce frictional drag have also been proposed. Generally, it is known that the smoother the pool deck surface, the more severe is the surface tension resulting in suction or sticking of the fabric to the deck.
One of the major problems with these artificial coverings, such as an artificial turf, is the fact that these artificial turfs can become very slippery and hazardous when wetted. Moreover, even if strategically placed, mats of artificial turf or other material to reduce surface tension can be a hazard from tripping or the like. Furthermore, the use of an artificial turf or similar ground covering is frequently objectionable to the pool owner because of the poor esthetics provided.
There have been proposals to introduce air beneath the fabric in order to lift the pool cover fabric from the surface of the swimming pool deck. This can be accomplished by adding an additional mechanical device to introduce air underneath the edges of the swimming pool cover and thereby attempt to raise the cover slightly off of the deck to ride on an air cushion. However, this usually results in substantial construction work resulting in substantial expense and the installation of additionalmechanical devices. Another way to provide this reduced frictional effect is to employ perforated pipes slightly below the surface of the swimming pool deck to thereby also provide an air cushion. However, again this results in substantial additional cost of construction and, moreover, has only been found to be marginally effective.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to a swimming pool cover capable of being pulled across a surface with reduced generation of frictional force between the undersurface of the cover and the surface on which the swimming pool cover is moved. In accordance with this invention, the swimming pool cover is provided with a plurality of depending elements on its undersurface which engage the surface on which the cover is moved and without allowing the undersurface of the cover itself to engage a surface on which the cover is moved.
The undersurface of the swimming pool cover of the invention is actually textured in such a way so as to create the depending elements which engage a surface on which the cover is pulled and thereby reduce the amount of surface frictional force which might otherwise be generated.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described the invention in general terms, reference will now be made to the accompanying drawings in which:
Figure 1 is a schematic top plan view of a typical swimming pool configuration along with an automatic pool cover assembly designed to cause extension and retraction of a pool cover over the swimming pool;
Figure 2 is a schematic side elevational view showing a corner portion of the fabric swimming pool cover raised and partially turned over in order to illustrate a surface configuration on the underside thereof in accordance with the present invention;
Figure 3 is a side elevational view, similar to Figure 2, and showing a corner portion raised and partially turned over of a modified form of pool cover in accordance with the present invention;
Figure 4 is a sectional view showing a portion of the swimming pool cover of Figure 3;
Figure 5 is a fragmentary perspective view of the underside of a modified form of swimming pool cover in accordance with the present invention;
Figure 6 is a bottom plan view of the swimming pool cover of Figure 5, showing a rib construction on the undersurface thereof; and
Figure 7 is a fragmentary perspective view showing the underside of still a further modified form of pool cover using a mesh fabric on the undersurface in accordance with the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now in more detail and by reference characters to the drawings, P designates a conventional swimming pool which, in the illustrated embodiment, has somewhat of a kidney shape or other irregular shape.
Although most swimming pools are of a rectangular construction, many have an irregular shape, such as that shown in Figure 1, particularly when the swimming pool is located in a private dwelling structure.
Provided for use with the swimming pool P, as shown in Figure 1, is a swimming pool cover assembly 20. This assembly typically is provided with a pair of side rails or tracks 22 located to carry the swimming pool cover 24 across the swimming pool, either when extending same or retracting same. The swimming pool cover 24 is typically rolled upon a spool (not shown) and driven back and forth by means of a drive mechanism 26. This overall construction of moving the swimming pool cover is conventional and is shown in several of the previously mentioned U.S. patents.
The swimming pool fabric cover sheet 24 is typically provided with an upper or top surface 28, as well as a bottom surface 30, as best shown in Figure 2. The bottom surface of the swimming pool cover is provided with a plurality of depending elements located to move upon a surface over which the swimming pool cover is pulled. These elements may adopt any of a plurality of different forms, as hereinafter described, providing a lower surface configuration which precludes the major portion of the undersurface of the swimming pool cover from coming into contact with the surface over which the cover is moved.
One form of textured bottom surface of a swimming pool cover is shown in Figure 3 and which comprises a section of an artificial turf on its underside. Thus, by reference to Figures 3 and 4, it can be observed that the fabric cover 24 is formed of a sheet 32 which is the outer sheet and a lower substrate 34. In the embodiment as shown in Figures 3 and 4, the sheet is inverted in its normal position with respect to Figure 4. Thus, the sheet 32 has a bottom surface 36 upon which the substrate 34 is secured. This substrate 34 may be secured to the bottom surface 36 of the sheet 32 by any conventional means, such as adhesives, plastic welding, stitching or the like.
The substrate 34 is provided with a plurality of outwardly extending projections 38, which in a normal artificial turf, simulates grass blades. In this case, the projections 38 are highly effective in that they substantially reduce surface contact between the undersurface of the fabric pool cover 24 and the upper surface of the deck.
Figures 5 and 6 illustrate another embodiment of a fabric cover 40 comprising a rollable and flexible sheet 42, which also has a relatively smooth upper surface 44 and a bottom surface 46. The sheet in Figures 5 and 6 is inverted in position, such that the bottom surface 46 appears upwardly presented.
The sheet 42 is provided on its bottom surface 46 with a textured surface configuration 48 which, in this embodiment of the invention, comprises a plurality of ribs 50. These ribs may be integrally formed with the sheet 42, particularly where the latter is formed of a plastic material. The ribs 50 are only slightly spaced above the bottom surface 46 of the sheet 42 so as to again reduce the surface contact with the pool deck. It can be seen that with the textured surface configuration 48, only a relatively small surface area contact exists when compared to the overall area of the bottom surface 46.
Figure 7 illustrates another modified form of fabric pool cover 60 and which is also shown in an inverted position. In this case, the pool cover 60 is comprised of a flexible and foldable and rollable sheet 62, having a relatively smooth upper surface 64 and a bottom surface 66. Secured to the bottom surface 66 is another fabric having a mesh-like sheet construction 68. This sheet 68 of the mesh fabric could be formed of the same material as the sheet 62 or it can be formed of a different material. Moreover, the sheet 68 may be secured to the sheet 62 by any conventional means as, for example, those means for securing the substrate 34 to the sheet 32, as previously described.
It should be observed that any form of textured surface which reduces surface area contact will also reduce the frictional effects in the area which could otherwise cause a vacuum between the pool cover and the deck surface and is thus contemplated within the present invention.

Claims

A swimming pool cover for extension and retraction over a swimming pool and where the cover may engage a portion of a deck surrounding the swimming pool during movement thereof and which pool cover comprises a flexible swimming pool cover sheet formed of a material capable of being rolled and unrolled and which sheet has a top surface and a bottom surface, an improvement comprising:

a surface configuration on said bottom surface of said sheet which is textured to substantially reduce surface area contact of the cover

sheet with the deck of the swimming pool during movement thereof to thereby reduce frictional effects between the cover and the deck.
The improvement in the swimming pool cover of Claim 1 wherein said surface configuration is formed of a separate substrate which is secured to said bottom surface of said sheet.
The improvement in the swimming pool cover of Claim 1 wherein said lower surface configuration on said bottom surface of said sheet is comprised of downwardly projecting ribs on said bottom surface, such that substantially the ribs contact the pool deck, as opposed to the bottom surface of said sheet during movement thereof to reduce frictional effects between the pool deck and the sheet.
The improvement in the swimming pool cover of Claim 1 wherein said surface configuration on said bottom surface comprises a mesh screen-like substrate on said bottom surface of said sheet which thereby provides a lower surface configuration to reduce surface area contact of the bottom surface of the sheet with the deck during movement thereof to thereby reduce frictional effects between the pool deck and the sheet.
The improvement in the swimming pool cover of Claim 1 wherein a substrate is on said bottom surface of said sheet having a plurality of downwardly extending projections which form a lower surface configuration, such that only the projections engage the deck to reduce area contact of the bottom surface of the sheet with the pool deck during movement thereof to thereby reduce frictional effects between the pool deck and the sheet.
The improvement in the swimming pool cover of Claim 1 said lower surface configuration is flexible so as to be capable of being rolled with said pool cover sheet.
A method of reducing frictional effects between a flexible and rollable swimming pool cover and a swimming pool deck when a swimming pool cover is moved across the deck to cover the swimming pool or retracted from a covering position over the swimming pool and wherein said swimming pool cover is slidably mounted in a pair of tracks which allow movement across said swimming pool, an improvement comprising:

providing a textured surface configuration on a bottom surface of said swimming pool cover to reduce surface area contact of the swimming pool cover with the deck of the swimming pool during movement thereof to thereby reduce frictional effects between the swimming pool cover and the deck of the swimming pool.