U.S. patent application number 09/847739 was filed with the patent office on 2002-08-29 for swimming pool cover having reduced friction during slidable movement.
Invention is credited to Dunn, David, Last, Harry J., Martin, Keith J..
Application Number | 20020116756 09/847739 |
Document ID | / |
Family ID | 26955658 |
Filed Date | 2002-08-29 |
United States Patent
Application |
20020116756 |
Kind Code |
A1 |
Martin, Keith J. ; et
al. |
August 29, 2002 |
Swimming pool cover having reduced friction during slidable
movement
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.
Inventors: |
Martin, Keith J.; (US)
; Dunn, David; (US) ; Last, Harry J.;
(Kailua, HI) |
Correspondence
Address: |
ROBERT J. SCHAAP
Suite 188
21241 Ventura Boulevard
Woodland Hills
CA
91364
US
|
Family ID: |
26955658 |
Appl. No.: |
09/847739 |
Filed: |
May 2, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60272659 |
Feb 28, 2001 |
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Current U.S.
Class: |
4/502 |
Current CPC
Class: |
E04H 4/101 20130101 |
Class at
Publication: |
4/502 |
International
Class: |
E04H 004/00 |
Claims
Having thus described the invention, what we desire to claim and
secure by letters patent is:
1. 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, said
swimming pool cover comprising: a) flexible swimming pool cover
sheet formed of a material capable of being rolled and unrolled; b)
said sheet having a top surface and a bottom surface; and c) 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.
2. The swimming pool cover of claim 1 further characterized in that
said surface configuration is formed on the bottom surface of said
sheet.
3. The swimming pool cover of claim 1 further characterized in that
said surface configuration is formed of a separate substrate which
is secured to said bottom surface of said sheet.
4. 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, said
swimming pool cover comprising: a) flexible swimming pool cover
sheet formed of a material capable of being rolled and unrolled; b)
said sheet having a top surface and a bottom surface; and c) a
lower surface configuration on said bottom surface of said sheet
which 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.
5. 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, said
swimming pool cover comprising: a) flexible swimming pool cover
sheet formed of a material capable of being rolled and unrolled; b)
said sheet having a top surface and a bottom surface; and c) a mesh
screen-like substrate on said bottom surface of said sheet
providing 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.
6. 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, said
swimming pool cover comprising: a) flexible swimming pool cover
sheet formed of a material capable of being rolled and unrolled; b)
said sheet having a top surface and a bottom surface; and c) a
substrate 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.
7. The swimming pool cover of claim 1 further characterized in that
said lower surface configuration is flexible so as to be capable of
being rolled with said pool cover sheet.
8. The swimming pool cover of claim 1 further characterized in that
said top surface of said sheet is generally smooth.
9. An improvement in a rollable fabric swimming pool cover of the
type which extends over and retracts from its extended position
over a swimming pool and which may engage a portion of a swimming
pool deck during movement thereof, said improvement comprising: a)
a textured surface configuration on a bottom 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 and to
thereby reduce frictional effects between the swimming pool cover
and a swimming pool deck.
10. The improvement in the rollable fabric swimming pool cover of
claim 9 further characterized in that said textured surface
configuration is integral with the bottom surface of said swimming
pool cover.
11. The improvement in the rollable fabric swimming pool cover
claim 9 further characterized in that the improvement comprises a
separate substrate secured to the underside of rollable fabric
swimming pool cover and which contains a textured surface
configuration thereon.
12. The improvement in the rollable fabric swimming pool cover of
claim 9 further characterized in that the improvement comprises
downwardly projecting ribs on the bottom surface of said fabric
cover, such that the ribs substantially contact the pool deck, as
opposed to the bottom surface of the fabric pool cover, during
movement thereof.
13. The improvement in the rollable fabric swimming pool cover of
claim 9 further characterized in that the improvement comprises a
mesh-like substrate on the bottom surface of said sheet providing a
surface configuration to reduce surface contact of the bottom
surface of the pool cover with a pool deck.
14. The improvement in the rollable fabric swimming pool cover of
claim 9 further characterized in that the improvement comprises a
bottom surface configuration on said pool cover with a plurality of
outwardly extending projections, such that only that the
projections engage the swimming pool deck to reduce area contact
therewith.
15. The improvement in the rollable fabric swimming pool cover of
claim 9 further characterized in that the improvement comprises a
lower flexible surface configuration which is flexible as to be
capable of being rolled with said pool cover sheet.
16. 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 removed across the deck to cover the
swimming pool or retracted from a covering position over the
swimming pool, said method comprising: a) mounting said swimming
pool cover in a pair of tracks which allow movement across said
swimming pool; and b) providing a textured surface configuration on
the 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.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] 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.
[0003] 2. Brief Description of the Related Art
[0004] Automatic swimming pool covers have become quite popular in
recent years both for purposes of maintaining cleanliness of a
swimming pool, maintaining heat in the body of water, and also as a
mean of safety. Many automatic swimming pool covers are effective
in that they are capable of being walked upon by children so that
the incidence of potential drowning is dramatically reduced.
[0005] 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. Pat. No. 3,060,455 to Joe H. Lamb, U.S. Pat. No. 4,001,900
to Joe H. Lamb, U.S. Pat. No. 4,464,801 to Joe H. Lamb, U.S. Pat.
No. 4,939,798 to Harry J. Last, U.S. Pat. No. 3,277,498 to Myron
Kleinbard, et al, as well as numerous others.
[0006] In the automatic swimming pool covers, a reel is provided
for winding the swimming pool cover upon the reel when the latter
is retracted from the body of water in the swimming pool and the
fabric is unspooled from the reel when it is desired to cover the
body of water in that swimming pool. The drive mechanism for the
reel is designed to provide sufficient driving power to enable
movement of the swimming pool cover across the pool deck and the
body of water in the swimming pool. Due to the fact that the
substantial portion of the fabric is pulled across the water
surface and the swimming pool cover is effectively supported by
that water surface, these automatic pool covers operate quite
effectively. The water in the pool actually provides a type of
lubricating action and a low friction surface over which the
swimming pool cover can be moved.
[0007] 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.
[0008] Many swimming pool are not rectangular and have a variety of
shapes, such as kidney shaped pools and the like. These pools may
also be covered with automatic pool covers. As a matter of
practicality, the automatic cover is similar to a horizontal blind,
in that, coverage of a rectangularly shaped pool is accomplished by
superimposing a rectangularly shaped pool cover over the swimming
pool. In the case of the non-rectangular swimming pool, a
rectangularly shaped pool cover is imposed over this
non-rectangular shape. Thus, and in this case, the pool cover side
tracks must be mounted on the top of the pool deck surface and
necessarily a substantial portion of the pool cover fabric is
pulled or dragged across the pool deck.
[0009] It has been well established in the swimming pool industry
that when a pool cover fabric is dragged across a pool deck, the
amount of force required to retract or extend the cover increased
in proportion to the amount of fabric that is dragged across the
deck, as opposed to a water surface. If more than thirty-five to
forty percent of the fabric is dragged across the pool deck, a
severe strain is imposed on the automatic pool cover mechanism
almost to the point where it can result in damage if not breakdown
of the entire automatic drive system. However, when the deck is
wetted, either by rain, splashing of water from the pool onto the
deck surface, or from simply opening or closing the cover several
times, thereby transferring water from the undersurface of the
cover to the deck, the drag force would multiply to the point where
the fabric cover could not move and would result in severe damage
or a complete breakdown of the automatic drive mechanism. This is
due to the surface tension and, in effect, the suction of the
wetted fabric to the pool deck.
[0010] Although the frictional effects of dragging a swimming pool
cover across a body of water is significantly less than the
frictional effects of the dragging the cover across a solid
surface, such as a swimming pool deck, the effects arising from
pulling movement of the cover across a body of water still exist.
Depending upon the size of the body of water, the frictional
effects of even moving the swimming pool cover across that body of
water can be substantial.
[0011] 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.
[0012] 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.
[0013] 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 additional mechanical
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.
OBJECTS OF THE INVENTION
[0014] It is, therefore, one of the primary objects of the present
invention to provide a swimming pool cover which has a surface
texture such that it is capable of reducing the frictional effects
created by movement of the swimming pool cover across the body of
water in a swimming pool.
[0015] It is another object of the present invention to provide a
swimming pool cover of the type stated which has a roughened
surface configuration on its underside to reduce surface area
contact between the swimming pool cover and the deck surface when
the swimming pool cover is moved thereacross.
[0016] It is an additional object of the present invention to
provide a swimming pool cover of the type stated having a lower
surface constructed such that only a relatively small surface area
of that lower surface resides in contact with a surface on which
the swimming pool cover is moved to thereby substantially reduce
friction therebetween.
[0017] It is also an object of the present invention to provide a
swimming pool cover of the type stated having elements depending
from the lower surface which engage a surface across which the
swimming pool cover is moved to thereby permit surface friction
generation only between the surface on which the cover is moved and
the elements on the undersurface of the cover.
[0018] It is a further object of the present invention to provide a
swimming pool cover of the type stated which can be manufactured at
a relatively low cost and which is highly effective in operation in
reducing the amount of force imposed on an automatic drive
mechanism.
[0019] It is another salient object of the present invention to
provide a method of moving a swimming pool cover across a surface
and simultaneously reducing the amount of frictional force which
would otherwise be generated during movement of that swimming pool
cover across the surface.
[0020] With the above and other objects in view, our invention
resides in the novel features of form, construction, arrangement
and combination of parts and components presently described and
pointed out in the claims.
BRIEF SUMMARY OF THE INVENTION
[0021] The present invention relies upon a non-smooth surface on
the underside of the swimming pool cover. In effect, the bottom
surface of the fabric has a surface configuration which is
roughened in order to substantially reduce surface area contact of
the swimming pool sheet with the deck during movement thereof. In
this way, the problems of the swimming pool cover sticking to the
deck have been overcome. In effect, the texturing or other surface
effect to the underside of the swimming pool cover sheet creates a
separation in the liquid on the deck or on the underside of the
sheet to break surface tension and prevent the suction created by
the liquid between the underside of the fabric cover and the
swimming pool deck.
[0022] 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. In other words, if the swimming pool cover is moved
across a deck, only the elements on the undersurface of the
swimming pool cover will be in contact with the deck and not the
major undersurface area of the cover itself. This will, of course,
substantially reduce the frictional force which might otherwise be
generated.
[0023] 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.
[0024] The elements which are formed on the undersurface of the
sheet may adopt a variety of forms. One of the preferred
constructions uses a grid pattern of depending elements, such as,
for example, a rectangular array of ribs. Thus, and in this way,
only the lower depending edges of the ribs reside in contact with
the surface on which the cover is moved. The ribs may be of a
regular rectangular shape or a diamond shape, or the like. In
another embodiment, the depending elements may adopt the form of a
plurality of spaced apart fingers which engage the surface on which
the cover is moved. This similarly will reduce the frictional
effects which would otherwise arise. In substance, any of a number
of desired surface configurations may be employed, such that the
depending elements ride on the surface across which the cover is
moved and thereby eliminate frictional contact between the major
undersurface area of the cover and the surface on which the cover
is moved.
[0025] The elements which depend from the undersurface of the
swimming pool cover are preferably integrally formed with the cover
in the formation of the cover. For this purpose, any of a number of
plastic forming operations may be used. Frequently, swimming pool
covers are formed of a vinyl material and, in which case, the
projections on the undersurface, such as the depending elements,
can be formed in a plastic molding operation. The cover may also be
formed of one or more layers of material and, in this case, the
depending elements would be formed on that layer which resides in
contact with the surface on which the cover is moved. The exact
technique for producing the elements on that layer would depend
upon the material of construction thereof.
[0026] This invention possesses many other advantages and has other
purposes which may be made more clearly apparent from a
consideration of the forms in which it may be embodied. These forms
are shown in the drawings forming a part of and accompanying the
present specification. They will now be described in detail for
purposes of illustrating the general principles of the invention.
However, it is to be understood that the following detailed
description and the accompanying drawings are not to be taken in a
limiting sense.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Having thus described the invention in general terms,
reference will now be made to the accompanying drawings in
which:
[0028] FIG. 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;
[0029] FIG. 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;
[0030] FIG. 3 is a side elevational view, similar to FIG. 2, and
showing a corner portion raised and partially turned over of a
modified form of pool cover in accordance with the present
invention;
[0031] FIG. 4 is a sectional view showing a portion of the swimming
pool cover of FIG. 3;
[0032] FIG. 5 is a fragmentary perspective view of the underside of
a modified form of swimming pool cover in accordance with the
present invention;
[0033] FIG. 6 is a bottom plan view of the swimming pool cover of
FIG. 5, showing a rib construction on the undersurface thereof;
and
[0034] FIG. 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
[0035] 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
FIG. 1, particularly when the swimming pool is located in a private
dwelling structure.
[0036] Provided for use with the swimming pool P, as shown in FIG.
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.
[0037] The swimming pool cover of the present invention is
comprised of a flexible and foldable and rollable fabric material
which may be, for example, a plastic sheet material or a cloth
material. In many cases, plasticized cloth material is employed.
However, the exact material used in the formation of the pool cover
is not critical in accordance with the present invention. 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 FIG. 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.
[0038] Any type of undersurface configuration which reduces surface
area contact with the swimming pool or the swimming pool deck or
similar surface and which thereby reduced frictional effects which
would otherwise arise can be employed. This undersurface
configuration is also effective to eliminate suction which is
sometimes created between a smooth undersurface of a fabric
swimming pool cover and a swimming pool deck, particularly when the
undersurface of the cover or the upper surface of the deck has been
wetted.
[0039] One form of textured bottom surface of a swimming pool cover
is shown in FIG. 3 and which comprises a section of an artificial
turf on its underside. Thus, by reference to FIGS. 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 FIGS. 3 and 4, the sheet is inverted in its normal
position with respect to FIG. 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.
[0040] 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.
[0041] FIGS. 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 FIGS. 5 and 6 is inverted in position, such that the
bottom surface 46 appears upwardly presented.
[0042] 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.
[0043] FIG. 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.
[0044] The mesh construction of the fabric sheet 68 is also
effective to reduce area surface contact between the fabric pool
cover and the surface of the pool deck, in the same manner as in
the previous embodiments. It should be observed in this respect
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.
[0045] Thus, there has been illustrated and described a unique and
novel swimming pool cover construction which meets and fulfills all
of the objects and advantages which have been sought. It should be
understood that many changes, modifications, variations and other
uses and applications which will become apparent to those skilled
in the art after considering the specification and the accompanying
drawings. Therefore, any and all such changes, modifications,
variations and other uses and applications which do not depart from
the spirit and scope of the invention are deemed to be covered by
the invention.
* * * * *