Aug- 4, 1970 E. c. GoULD 3,522,614
SWIMMING POOL STRUCTURE 4 Sheets-Sheet l Original Filed May lO, 1966 Aug. 4, 1970 E. c. GoULD- 3,522,614
SWIMMING PooL STRUCTURE original Filed May 1o,l 1966 4 sheets-sheet a /m/f/vra@ 5y fan/APD C. 60e/0 wwwmvm rroe/VEYJZ Aug 4, 1970 E. c. GouLD 3,522,614
v SWIMMING Poor. STRUCTURE Original Filed May 10. 1966 /Za FIG. .5"
4 Sheets-Sheet 5 '5% mw am 5w Aug. 4,---1970 E. c. GouLD SWIMMING POOL STRUCTURE 4 sheets-sheet 4 m w y /N ,47m/@vifs Original Filed May 1'0.' 1966 KUnited States Patent O 3,522,614 SWIMMING POL STRUCTURE Edward C. Gould, Wayzatha, Minn., assignor to Doughboy Industries, Inc., New Richmond, Wis., a corporation of Wisconsin Continuation of application Ser. No. 548,958, May 10, 1966. This application Uct. 14, 1968, Ser. No. 778,356
Int. Cl. E641: 3/18 U.S. Cl. 4-172.19 1 Claim ABSTRACT F THE DISCLOSURE A swimming pool structure for use with a flexible plastic liner comprising a generally vertically oriented substantially continuous tensile membrane shaped into a plurality of outwardly convex partially cylindrical sectors, adjacent sectors intersecting each other at an apex. A pluralityl of reinforcing posts each engaging the exterior surface of lthe membrane at one of the apices. The relative positioning of the sectors and radii thereof being so arranged that a `line passing through the vertical cross-sectlonal -plane of each post approximately bisects a line joining the respective centers of adjacent sectors.
This application is a continuation of application Ser.
No. 548,958, filed May 10, 1966, now abandoned.
`the tensile membrane being supported by vertical post structures against the force exerted by the ffowable material to be retained, each post structure being interposed between adjacent arcuate sectors, the latter being arranged and constructed so that the lateral components of tension `force are in equilibrium and will therefore not tend to displace the reinforcing post in the direction of the lateral components of force.
With this type of arrangement, many types of retaining wall structures including closed continuous structures such as portable swimming pools may be constructed, such swimming poolstructures having shapes that approximate those architectural desirable shapes and configurations. It has further been found that many desirable low strength materials may be used in the construction of the novel retaining wall structures even though the particular shape and size of the retaining wall structure would seemingly indicate that such low strength materials could not be used.
These and other objectsl and advantages of this invention will more fully appear from the following description made in connection with the accompanying drawings wherein like reference characters referV to the same or similar parts throughout the several views, and in which:
FIG. 1 is a perspective view of a portion of a swimming pool employing the invention;
FIG. 2 is a cross-sectional view on an enlarged scale taken approximately along line 2-2 of FIG. 3 and looking in the direction of the arrows;
FIG. 3 is a transverse cross-sectional view taken approximately along line 3--3 of FIG. 1 and looking in the direction of the arrows;
FIG. 4 is a diagrammatic fragmentary plan view of the swimming pool;
FIG. 5 is a diagrammatic fragmentary plan view of a modified form of the invention;
FIG. 6 is a diagrammatic fragmentary plan view of a further embodiment of the invention;
FIG. 7 is a top plan View of a further modified form of the invention;
FIG. 8 is a cross-sectional vie-w on an enlarged scale taken along line 8-8 of FIG. 7 and looking in the direction of the arrows.
Referring now to FIGS. 1 to 4l itwill be seen that one embodiment of the novel retaining wall structure is incorporated in a portable swimming pool, designated generally by reference numeral 10, and which is of the type located essentially above the surface of the ground. The swimming pool structure 10 is comprised of an elongate somewhat flexible membrane 11 constructed of a material which is capable of sustaining tension loads. In the ernbodiment shown, the membrane is formed of a sheet of suitable metallic material such as steel that is of relatively thin gauge and is flexible.
The present invention contemplates the use of retaining wall structures which are arranged and constructed so that the particular membrane used may be any suitable material which will withstand tension at the desired design parameter. Thus, the present arrangement permits the use of very low strength materials inthe construction of structures such as swimming pools and the like. Referring again to FIG. l, it will be seen that the portable swimming pool shown is of a generally rectangular configuration having vertical sidewalls which extend upwardly above the surface of the ground.
The tensile membrane 11 which forms the sidewall of the swimming pool structure 10, in the embodiment shown is preferably a continuous metallic thin gauged steel sheet which extends upwardly from the surface of the earth, and is reinforced by plurality upright of post 12 disposed in spaced apart relation. It is pointed out that the embodiment of the portable type swimming pool 10 disclosed, includes an inner liner 13 which is formed of a suitable liquid impervious material such as plastic or the like. This liner 13 closely conforms to the volumetric space defined by the retaining wall structure and the surface of the earth, as a result of the outwardly or horizontally directed forces exerted by the water, these forces being transmitted to the membrane 11 and posts 12. The tensile membrane 11 of the swimming pool 10` shown in FIGS. 1 through 4 is generally shaped into rectangular configuration, the bottom of the pool being defined by the surface of the earth and the pool being provided with an impervious liner 13. In erecting the pool 10, the surface of the earth may be excavated to form a depression near the center or the swimming pool may be erected from a substantially flat surface without any excavation. It will be seen that the tensile membrane 11 is shaped into a plurality of continuous arcuate sectors 14 and that the post structures 12 are disposed between adjacent of said arcuate sectors and engage the tensile membrane substantially throughout its entire height. Although any desirable shaped vertical post structure 12 may be used, one typical post and post supportwhich may be used is the form illustrated in FIGS. 1-3 and which comprises a generally channeled or hat-shape structure including an upper portion 15 and a lower portion 16 extending at substantially right angles thereto. The lower portion 16 may be buried in the ground to anchor the same, or in the event that other shaped posts are used, suitable bracing which extends diagonally downward and outwardly may be used to brace the post against the horizontal force exerted outwardly thereagainst.
A plurality of lower positioning rails 17 are provided and are positioned upon the surface of the ground and eX- tend between adjacent post structures 12. It will be noted that these positioning rails 17 are of generally arcuate conguration, and are preferably constructed of a suitable rigid material such as steel or the like. These bottom rails are of generally rectangular shaped configuration and have an upwardly opening groove 18 therein throughout substantially their respective lengths. It will be noted that one wall 19 of the positioning rails 17 project slightly upwardly beyond the top wall of the rail as best seen in FIG. 2. These bottom positioning rails 17 receive the lower portion of the tensile membrane 11 therein and serve to impart the proper curvature to the tensile membrane so that the arcuate sectors 14 are formed. It will be noted that these positioning rails 17 extend between adjacent posts with the convex surface thereof projecting outwardly. The bottom rails do not function structurally and therefore need not be attached to the posts.
An elongate generally inverted U-shaped coping element 20 formed of relatively rigid plastic material is positioned over the upper edge of tensile membrane 11, the upper peripheral edge portion of the plastic liner 13 being interposed between the coping element and the membrane. To this end it will be noted that the plastic liner 13 is folded over the upper peripheral edge of the membrane and the coping element 20 serves to retain the same in mounted relation thereon. A plurality of top rail sections 21 are provided and each top rail section is positioned upon and extends between a pair of the post structures 12 and is secured thereto by any suitable securing means such as screws, bolts, or the like. It will be noted that the web portion 22 of each top rail section 21 has a width dimension substantially greater than the corresponding thickness dimension of most of the post structures 12 and projects outwardly therebeyond as best seen in FIG. 2. Thus, these top rail sections are of sufficient width so that each section overlies one of the arcuate sectors 14 of the tensile membrane 11. The top rail not only serves to protect the top of the membrane but also imparts a more desirable appearance to the upper symmetry of the swimming pool structure.
Referring again to FIGS. l, 3, and 4, it will be seen that the tensile membrane is formed into a plurality of short radii arcuate sectors 14, the radius dened in each arcuate sector being located substantially outwardly of the general center of the swimming pool structure. It has been found that by forming the tensile membrane into short radii arcuate sectors, substantially the entire tensile strength of the membrane will not be exceeded.
The force exerted by the retained liquid of the swimming pool structure is borne primarily by the tensile membrane 11 and thence to the post structures 12. Thus, the tensile membrane 11 is under constant tension but the tension exerted on each arcuate section is substantially independent of the other arcuate sectors. Referring again to FIG. 4, it will be seen that the tension exerted on each arcuate sector 14 has been represented by vector line 23 and is tangent to the arcuate sector at the post structure 12. The lateral component of this tension force as represented by the vector line 24 and this lateral force vector line 24 is disposed at right angles to the vector line 25 which represents the normal component of tension exerted on the arcuate sector, and on the associated post structure 12. This normal vector or component 25 passes through the cross-sectional axial center of the associated post structure 12 and this component force acts upon the post as well as each arcuate sector 14.
The lateral component of force 24 acting upon adjacent arcuate sectors 14 are transmitted to the post structure 12 between such adjacent arcuate sectors 14 and tend to tilt the post in the direction of these lateral components of force. However, by designing the arcuate sectors 14 so that the lateral components 24 of force acting on adjacent arcuate sectors are in a state of equilibrium, the post structures 12 may then be balanced against a tilting action in a lateral direction. The normal component of force 25 which is transmitted to the post structures 12 will be a force of the same magnitude as the force exerted by any other structural system spanning between the posts. Thus, the post structures 12 may be easily arranged and constructed to be capable of withstanding the load or normal component of force, represented by line 25, acting thereagainst. The post structures may be of any suitable construction and support.
By using short radii sectors, the force to be resisted by the membrane in each sector will be substantially less than the force to be resisted upon a continuous surface of substantially longer radius. Therefore, a plurality of relatively small arcuate sectors will be able to sustain a substantially greater load than a continuous surface corresponding in overall size the plurality of arcuate sectors. It will therefore be seen that in constructing a conventional circular swimming pool of the portable type using a tensile membrane formed of relatively thin gauged sheet steel, the size of the swimming pool structure will be limited since the size of the pool will necessarily be dependent upon the strength of the tensile membrane being used. However, by shaping the tensile membrane into a plurality of short radii arcuate sectors, with supporting post structures interposed between adjacent arcuate sectors, a larger size circular pool of the same depth may be constructed. Thus portable swimming pool structures may now be constructed of low strength tensile membranes so that many more lower strength materials are now available than was heretofore contemplated in comparable pool structures.
The present system also permits closed retaining wall structures such as swimming pools of the type disclosed herein, to be formed of low strength materials and to be constructed in many of the shapes and configurations which approximate those architecturally desirable shapes and coniigurations. To this end, it is pointed out that While generally circular shaped home type portable swimming pools constructed of low strength economic materials are available, these pools are not only limited in size with respect to materials being used, but these conventionally constructed pools can not be built in many of the desirable architectural shapes and still utilize the economic low strength materials. Thus, the generally rectangular pool of a size corresponding to the conventional circular pools could not be built utilizing substantially the same low strengh materials and utilizing substantially the same structural parts. As pointed out above, it is essential that the adjacent arcuate sectors 14 be so constructed that the lateral components 24 of force which act on each post structure be in a state of equilibrium to prevent tilting of the post structures in a lateral direction.
The tension in each arcuate sector of the membrane is represented by the line 23 which is tangent to an arcuate sector at the post structure 12, and this tension may be determined by the product of the radius of the arcuate sector, the unit weight of the material (liquids, pulverulent materials and granular or particulate materials) being retained, and the depth of the material at the elevation being considered. It has been found that when a generally rectangular shaped pool is to be constructed, of a size comparable of the twenty-eight foot round pool, and constructed from a metallic material of approximately .0l57i.003 inch, it is desirable to have the arcuate sectors having a radius of approximately five feet.
Therefore, after the general shape and size of the pool has been selected, the spacing between adjacent posts will be first determined. It has been found that the steel tensile membranes used in swimming pool structures and having a gauge or thickness of approximately .0l57i.003 inch may be formed into a round pool of 28 feet diameter and approximately four feet deep. Arcuate sectors having spans of approximately four feet and radii of approximately five feet will allow the construction of a pool on unlimited shape and size anda depth of feet using the same membrane material at the same stress in the membrane. The determination of the post spacing, radius and depth can be adjusted to meet any desirable condition.
Thus, one arcuate sector is formed and the lateral component of force is determined at a selected depth which sired, the same radius will also be used in forming the next arcuate section. Thel product of radius 26 of the Vn'ext arcuate section and the cosine of the angle a2 designated by the reference numeral 29 will be equal to that value which represents the lateral component of force of lthe rst described arcuate sector. As pointed out above,
when the lateral components of force of adjacent arcuate 'sectors are-in a state of equilibrium, sidewise tilting of tthe post structure 12 between such adjacent arcuate sec- 'tors will be prevented'. Thus, the post will require sufficient strength to withstand the normal component of force represented by the line 25 and this may be readily determined. t
` Referring now to FIG. 5, itwill be seen that a diafgrammatic illustration of a slightly modified form of the swimming pool structure designated by the reference numeral 10a'is there shown. The swimming pool structure includes the tensile membrane 11a comprised of a plurality of' arcuate sectors 14a and supported by post structure 12a/It will be noted that the post structures 12a along a given side of the swimming pool structure are disposed in alignment with vrespect to each other, and it will also be noted that the centers 30a of radii of each 'of the arcuate sectors along one side portion lof the pool are also disposed in` alignment with respect to each other 'as represented by the line 31a. It will be further noted that the arcuate sector, which denes a corner portion of the "swimming pool structure 10a, isV defined by substantially longer arc than the adjacent arcuate sectors, but it is pointed out that the lateral components 24a of force exerted on adjacent arcuate sectors 14a and acting on the post structures 12a therebetween will be in a state of equilibrium, even though one of these arcuate sectors does extend around a corner with a slight directional change.
l-It will? be 'noted that the angle a1 designated by the reference numeral 27a is substantially equal to the angle Aa2 designated by the reference numeral 29a. The respective radii 26aof the arcuate sectors are also substantially equal, although the arcuate sector 14a which defines the v corner of the swimming pool structure is substantially longer, `.this longer span being occasioned by the change in direction of the position of post structures 12. In the event that the posts are to have bearable spacing therebetween,
t it will be seen that after thepost structures have been in- `serted, and one particular arcuate sector has been formed, the remaining arcuate sectors and the radii defining each may be readily determined by satisfying the condition that of equalizingthe horizontal components of force acting on each `post structure.
Referring now to FIG. 6, it will be seen that a fragmentary portion 10b of the swimming pool structure is there shown, and this swimming pool structure is generally of 4circular configuration. The swimming pool structure 10b is comprised of a tensile membrane 11b formed of the same material as that disclosed in the embodiments of FIGS. 1-5 and having the same gauge as that shown in FIGS. 1-5.'The tensile membrane 11b includes a plurality of arcuate sectors 14b having post structures 12b interposed between adjacent sectors. The lateral component of force 24b of each of the arcuate sectors 1411 that act upon the post structure 12b therebetween are in a state of equilibrium. It will again be pointed out that the lateral components of force exerted on the respective adjacent arcuate sectors will be in a state of equilibrium when the product of the radius 26b of one arcuate sector and the cosine of the angle a1 represented by the reference numeral 2lb, is equal to the product of the radius 2611 of the other arcuate sector and the cosine of the angle a2 represented by the reference numeral 29b.
In the arrangement shown, the spacing of the post structures will be substantially equal (although the spacing need not necessarily be substantially equal) and the post structures will define a circular pattern. Similarly, the centers 30h of the arcuate sectors 14b, will also be arranged in a circular pattern as shown by the line 31b. By shaping the tensile membrane into a plurality of arcuate sectors, with post structures 12b interposed between adjacent sectors, a much larger generally circular swimming pool structure 10b may be formed from the same gauge tensile membrane material than could be formed if the' swimming pool 'structure was substantially circular in shape without the arcuate sectors. Thus, it will be seen that the present invention is especially adaptable for use in forming portable swimming pool structures.
Although my unique retaining wall structure has been described hereinabove in a swimming pool structure, it is also pointed out that the retaining wall structure may also be used for retaining other materials besides liquids. For example, flowable materials which behave somewhat like liquids, such as particulate materials including earth, sand, gravel, crushed rock, grain, may also be retained from a unique retaining wall structure. The retaining wall structure will effectively retain pulverulent materials which are also owable such as flour, cement and the like.
The retaining wall structure is preferably used as a continuous closed structure, although unclosed retaining wall structures are also possible. The tensile membrane, while being described as formed of an impervious sheet steel, may also be formed of metallic plate stock, and mesh type metallic material. To this end, it is pointed out that while metals other than steel may be used as a tensile membrane, the tensile membrane may be formed of still other materials such as plastic, reinforced` concrete, prestressed concrete, wood, paper and brous material.
Referring now to FIGS. 7 and 8, it will be seen that a further embodiment of the swimming pool structure, designated generally by the reference numeral 10c is there shown. The configuration of the modified structure 10c is comprised of an elongate closed continuous tensile membrane 11C, which is shaped and contoured into generally kidney-shaped configuration. The tensile membrane 11C is supported along one convex surface portion thereof by .plurality of post structures 12e .and is supported by a pair of post structures 12a' adjacent its concave surface portion.
The tensile membrane 11C is formed into a plurality of relatively small arcuate sectors 14e throughout one convex side of the swimming pool structure and the small arcuate sectors 14C are of substantially identical size and shape with respect to each other. However, the end portions of the tensile membrane are dened by a pair of relatively large arcuate sectors 14d which are interconnected by relatively small arcuate sector 14e. The larger arcuate sector 14d are defined by radii of the same size as those that define the arcuate Sectors 14C. The post structures 12C are interposed in supporting relation between adjacent arcuate sectors 14e. y
Referring now to FIG. 8., it will be seen that the post structures 12c each include an upper portion 15e which is of channel or hat shaped cross-sectional configuration and which is rigidly secured at its lower end to an elongate horizontally disposed lower portion 16C intermediate the ends of the latter. This lower portion 16C is of channeled shape configuration, with the concavity thereof facing upwardly so that the lower end of the upper portion 15C is received within the lower portion 16C. An elongate brace member 40C which is also of channeled shape configuration has one end thereof rigidly connected to the median part of the upper portion 15e and has its other end thereof rigidly secured to the lower portion 16C. It will be noted, that the outer end of each lower portion 16C for each post structure 12C, is rigidly secured to a suitable footing structure 41C formed of a suitable rigid material having desirable strength characteristics, and which is preferably embedded within the ground. A plurality of elongate deck members 42e of corrugated crosssectional configuration are mounted upon the upper surface of the inner ends of the lower portion 16C and these deck members are arranged in end-to-end relation to form a continuous deck structure as best seen in FIG. 7. This deck structure is covered with sand or soil in the manner of the embodiment of FIGS. 1 through 4.
The pair of post structures 12d are of substantial identical construction to the post structures 12C but are of larger dimension than the smaller post structures 12e. As pointed out above, the post structures 12e are each disposed between a pair of arcuate sectors 14C, and the lateral components of force that acts upon the arcuate sectors 14C and thence upon the post structures 12e are in a state of equilibrium with respect to each other. Thus, it is again pointed out that the tensile membrane 11e is arranged and constructed so that the product of the radius of one arcuate sector 14e and the cosine of that angle (not graphically represented) corresponding to the angle a1 of the embodiments of FIGS. 1-6, is equal to the product of the radius of the other arcuate sector and the cosine of the corresponding angle. lIt is also pointed out that the swimming pool structure c may also be provided with a plastic liner in the manner of the embodiments of FIGS. 1 through 6.
The swimming pool structure illustrated in the drawings utilizes a liner for lining the entire volumetric space 'which contains the water, but it is pointed out that the tensile membrane itself may be used as an impervious part of the swimming pool, the plastic liner being secured to the lower marginal portions of the tensile mernbrane and defining the bottom portion of the pool and wherein the load at the bottom of the pool structure is sustained by the earth.
From the foregoing description, it will be seen that I have provided a novel retaining wall structure which has special utility in the construction of portable type swimming pools, and which permits the construction of such portable swimming pools with relatively low strength materials.
It will further' be seen that through the use of my invention, not only may low strength materials be used in such structures as swimming pools, but these swimming pools may now be formed in shapes approximating many of the desirable architectural shapes which was not heretofore possible with the low strength materials that are now used in conventional portable swimming pool structures.
Although in the preceding paragraphs, a portable swimming pool structure has been utilized as an exemplary structure which incorporates the features of the present invention may be incorporated in other structures. For example, various kinds of tanks or receptacles which are used for storage or shipment of liquids may utilize the principle of my invention as well as bins for the storage or shipment of pulverulent and particulate material. To this end, it is pointed out that receptacles or receivers for the storage and shipment of grain may incorporate the principles of my present invention as well as those receptacle structures which are used for the storage and shipment of tine pulverulent materials such as powders.
Further, the principle features of the present invention may also be advantageously `incorporated in receivers for gases.
The expression continuous when used to describe the tensile membrane is intended to include a membrane formed of separate pieces but joined together, as well as a single piece structure.
Other types of retaining structures may be constructed through the use of the present invention such as retaining walls for retaining earth in the construction of lagoons, harbors, marinas, reflection pools and the like.
Thus, it will be seen that I have provided a novel swimming pool structure which is not only of simple inexpensive construction but one which is capable of functioning in a more eicient manner than any heretofore known comparable structure.
It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the various parts without departing from the scope of my invention.
1. An elongate swimming pool structure for use with a flexible plastic liner comprising:
a generally vertically oriented substantially continuous tensile membrane shaped into elaborate kidney shaped configuration including a plurality of small arcuate sectors along one side thereof, a pair of large end arcuate sectors at opposite ends thereof and a small arcuate sector between said end sectors and opposed to said first mentioned small sectors, adjacent arcuate sectors intersecting each other at an apex, each arcuate sector being deined by a radius of predetermined magnitude,
a plurality of reinforcing posts each engaging the exterior surface of said membrane at one of said apices, each post including an elongate horizontal post member adapted to be embedded in the ground, a vertical post rigidly connected with each horizontal post adjacent the central portion thereof and extending upwardly therefrom, an oblique brace member having an upper end connected to the vertical post member and extending downwardly and outwardly therefrom and having the outer end thereof affixed to one end of said horizontal post member, a plurality of elongate rigid decking members spaced inwardly of said tensile membrane and extending between and engaging the inner ends of adjacent side-Iby-Side horizontal post members, a vertical plane disposed substantially perpendicular to a line joining the centers' of adjacent arcuate sectors at Whose intersecting apex a post is positioned substantially bisecting the post located at the intersecting apex whereby the horizontal components of force acting on each post through adjacent arcuate sectors are in a state of equilibrium and each of said horizontal posts having means adjacent the outer end thereof to prevent displacement thereof.
References Cited UNITED STATES PATENTS Re. 21,531 8/1940 Peterson 52-63 1,652,415 12/1927 Schenker 52-169 1,668,179 5/ 1928 Williams 220-1 2,860,806 11/1958 Yanowitz 220-1 3,193,847 7/1965 Moshura 4-172 3,274,621 9/1966 Diemond et al. 4-172 3,315,278y 4/1967 Schatzki 4-172 LAVERNE D. GEIGER, Primary Examiner H. K. ARTIS, Assistant Examiner U.S. Cl. X.R. 51-169