US3601397A

US3601397A - Play center having table, swing, slide and gymnastic bars

Info

Publication number: US3601397A
Application number: US863603A
Authority: US
Inventors: Edward T Carlin; Bobbie L White
Original assignee: Gym Dandy Inc
Current assignee: PAR INDUSTRIES Inc; ROTOCAST PLASTIC PRODUCTS Inc; Gym Dandy Inc
Priority date: 1969-10-03
Filing date: 1969-10-03
Publication date: 1971-08-24
Anticipated expiration: 1988-08-24
Also published as: FR2068196A5; AU2688371A

Abstract

A play center for home yard, patio, or recreation room use by preschool and grade school age children designed and constructed to encourage innovative play as well as conventional usage by such children. The play center is a fabricated structure composed of six main tubular frames; three novel platform assemblies providing a table, associated bench seats and a slide approach platform; a slide board; a swing; and variously disposed tubular cross braces and wide step structures forming ground or floor engaging outrigger members to prevent upsetting of the assembled unit, swing supports, chinning and gymnastic bars, steps and seats. These fabricated elements and subassemblies are joined together to form an assembled unit of generally cubical configuration when viewed from the sides and opposite ends and the ground or floor area, measuring roughly 3 feet by 7 feet, delimited by the main frame subassemblies which cooperates with the main frame subassemblies, table and associated benches to form a house area and tunnellike passage in innovative usage by preschool children.

Description

llnite States [72] Inventors Edward T. Carlin;

Bobbie L. White, both of Shreveport, La. [21 Appl. No. 863,603 [22] Filed Oct. 3, 1969 [45] Patented Aug. 24, 1971 [73] Assignee Gym-Dandy, Inc.

Bossier City, La.

[54] ELAY CENTER HAVING TABLE, SWING, SLIDE AND GYMNASTIC BARS 10 Claims, 18 Drawing Figs.

[52] 11.8. C1 272/56.5 R, 272/60, 272/62, 272/85, 297/157, 108/50 [51] lint. C1 A63b 17/00 [50] Field of Search 272/60, 56.5, 57, 62

[56] References Cited UNITED STATES PATENTS 1,126,082 1/1915 Reach 272/60 3,120,955 2/1964 Carlin 272/60 Primary Examiner-Anton O. Oechsle Assistant Examiner-Richard Dror Att0mey-Strauch, Nolan, Neale, Nies & Kurz ABSTRACT: A play center for home yard, patio, or recreation room use by preschool and grade school age children designed and constructed to encourage innovative play as well as conventional usage by such children. The play center is a fabricated structure composed of six main tubular frames; three novel platform assemblies providing a table, associated bench seats and a slide approach platform; a slide board; a swing; and variously disposed tubular cross braces and wide step structures forming ground or floor engaging outrigger members to prevent upsetting of the assembled unit, swing supports, chinning and gymnastic bars, steps and seats. These fabricated elements and subassemblies are joined together to form an assembled unit of generally cubical configuration when viewed from the sides and opposite ends and the ground or floor area, measuring roughly 3 feet by 7 feet, delimited by the main frame subassemblies which cooperates with the main frame subassemblies, table and associated benches to form a house area and tunnellike passage in innovative usage by preschool children.

PATENTEU AUG24 I97! FIG. I

SHEET 1 0F 7 (O N a 3 l: 8 2 IO 8 g IO IO Q A. m of) 8 v a N Q g m o B 8 8 w 0:) 3 O, (BM a; F 17 83 x k g 3 :5; f

r m iii R BY M m a I? x ml: 8

INVENTOR5 EDWARD T CARLIN BOBBIE L.WH|TE ATTORNEY5 PATENTEU AUG24|97| 3,601,397.

sum 2 0F 7 75 FIG 3 INVENTORS EDWARD T. CARLIN BOBBIE L,WHITE ATTOR hYS PATENTED 10241971 3,601; 3.97

sum 3 [1F 7 INVENTORS EDWARD T. CARLIN BOBBIE L.WH!TE ATTORNEYS PATENIED M824 Ian saw u or 7 INVENTOR',

fl fiwn ATTORNF E k EDWARD T. CARLIN BOBBIE L. WHITE PATENTEDAuB24|9n 3.601397 SHEET 5 OF '7 FIG I2 INVENTORI) EDWARD T. CARLIN BOBBIE L.WH|TE PATENTEuAus24|91| 3501.897

SHEET 6 OF 7 III/Ill I lI/I/I/I FIG 13 FIG. I4

INVENTORS EDWARD T. CARLIN BOBBIE LWHITE OR EYS PATENTEU AUB24|97| 3,601;

sum 7 BF 7 FIG I6 FIG I7 FIG I6 INVENTOR EDWARD T. CARLIN BOBBIE L.WH|TE ATTOR 5 PLAY CENTER HAVING TABLE, SWING, SLIDE AND GYMNASTIC BARS BACKGROUND OF INVENTION For the past 30 years the play centers offered to the public have generally employed a main frame of heavy tubular members formed by a pair of end A-frames connected at their apexes by a tie bar having straplike reinforcement members interconnecting its opposite ends to the upper ends of the legs of the A-frarne exemplified by U.S. Letters Pat. No. 2,800,949 to l. Horowitz issued July 30, 1957. This main frame tie bar has served to suspendingly mount swings, chain supported gym bars, gliders, and a device widely known as a Skyscooter" in side-by-side spaced relation and in some cases these conventional main frames have had sliding board assemblies mounted on the outer side faces on one of the end A- frames. For the most part, the length, width, height, and tubular size of these A-frame units have been designed of such magnitude to assure structural strength and stability that the play centers have been largely limited to yard usage because of their space requirements and these units afford little, if any,

play activities other than that provided by the equipment suspended from the main frame. As a consequence, the inherent make believe or innovative nature of the children for which they are designed is not'satisfied by such-play equipment and the children soon become tired or bored with such play centers. In the past additional pieces of equipment have been offered to satisfy the childrens desire for climbing, a

play house, tunnelling, and picnic activity. The present construction and the lighter weight tubular stock from which it can be constructed with structural strength and stability required for safety, provides for the first time a play center which may be set up for use indoors as well as in the home yard and is offered for use on covered patios, recreation rooms, or even spare rooms of homes and apartments to afford play centers useful even in inclement weather and a unit which may be readily moved from place to place when desired. In addition, the single unit of the present invention provides for climbing activities, picnic activities and innumerable innovative activities such as tunnelling, play house activities, a ranger lookout station, and the like.

SUMMARY OF INVENTION It, accordingly is a primary object of this invention to provide a childrens play center which provides the children not only with the usual swing, glider, sliding board, and gym bar activities but a picnic area, a climber, and innovative activities such as play house activities, lookout station activities, tunnelling and other play activities which are generated in the seeking, imaginative minds of children of the preschool and grade school age group.

Another important object of the present invention is to proport the upper end of a sliding board and a sliding board approach platform.

Still another object of the present invention resides in constructing the cross frame assembly above the outrigger stabilizing run at the other side with laterally spaced, vertically extending runs connected at vertically spaced intervals with laterally directed step members spaced vertically between the I ground level and the upper tubular run of the cross frame asterfitted ends, the lower ground engaging crossmembers being vide an antitilt stabilized play center for children composed of a pair of identical side frame members having support runs assuring line contact with a support surface, a cross frame assembly interconnecting the side frame members medially thereof and providing outrigger, ground or floor engaging, lateral, stabilizing runs providing line contact with said support surface laterally outwardly of said side frame members, and respective end frame assemblies interconnecting the side frame ends and providing outrigger, ground or floor engaging longitudinal stabilizing runs providing line contact with said support surface outwardly of the opposite ends of said play center.

A further object of the present invention resides in constructing the cross frame assembly above the outrigger stabilizing run at one side with laterally spaced vertically extending tubular runs connected at vertically spaced intervals with laterally directed step members spaced vertically between the ground level and midheight and a pair of laterally spaced, upwardly longitudinally directed, generally U-haped support bars cooperating with the laterally spaced vertical runs to supoffset laterally outwardly beyond the upper crossmembers to enable the upper crossmembers to be used respectively as a swing support and/or chinning and gym bar with the lower outward offset ground engaging crossmembers arranged to provide line contact with a support surface operative to resist the tilting forces of the play center when the swing moves outwardly in its swinging movement or the upper crossmember is used for chinning and gymnastic activities.

Another object of the present invention resides in providing a novel strap connector for securing the upper loop end of a swing support strap, rope or the like against relative axial and rotational movement with respect to the upper run of the end frame assembly.

Still another object of the present invention resides in providing a novel platform assembly composed of a pair of opposed channellike support rails and one or more channellike platform members fixedly end fitted into the opposed channels of the support rails without the need of separable fasteners of any kind.

A still further object of the present invention resides in mounting a vertically spaced pair of platform assemblies formed according to the previous object in vertically spaced relation to the lower runs of one end frame assembly and the adjacently related end runs of said side frame assemblies, the upper of said platform assemblies comprising a pair of platform members adjacently centered with respect to an opposed pair of support rails to form a table and the lower of said platform assemblies comprising a pair of platform members respectively connected to the adjacent opposed ends of a longer pair of support rails to form respective bench type seats extending in longitudinal parallelism to said table platform members.

BRIEF DESCRIPTION OF DRAWINGS Additional objects will appear from the following description and appended claims when read in conjunction with the accompanying drawings wherein:

FIG. 1 is a perspective view of a play center according to the present invention showing several children playing, some indulging in innovative activities encouraged by the novel unit of the present invention;

FIG. 2 is an end view of the play center of FIG. 1 as viewed from the left of FIG. 1;

FIG. 3 is an end view of the play center as viewed from the right of FIG. 1;

FIG. 4 is a side view of the play center of FIG. 1 as viewed from the side opposite that shown in FIG. 1;

FIG. 5 is a side view of one of the two main side frame assemblies showing the manner of assembly thereof;

FIG. 6 is a front view of the cross frame assembly main frame section the opposite vertical runs and the oppositely inturned runs of which form a part of the outrigger stabilizing structure for preventing side tilting of the play center;

FIG. 7 is an end view of one of the two end frame assemblies, the lower cross run of which is offset to the right with respect to the upper cross run as seen in FIG. 7 thereby adapting the end frame assembly to serve as an outrigger stabilizing structure for preventing end tilting of the play center;

FIG. 8 illustrates a tubular reinforcing frame assembly for completing and reinforcing the cross frame assembly when associated with the main frame section of FIG. 6;

FIG. 9 is a fragmental longitudinal sectional view through the end frame upper cross run to illustrate the novel swing strap connector of the present invention;

FIG. 10 is a view similar to that of FIG. 9 illustrating an alternate strap connector clamp bolt provided to conceal the threaded bolt end of associated nut midway within the upper end loop of the swing strap;

FIG. 11 is a perspective view of the platform construction of the present invention arranged with adjacently centered platform members to form the table or slide approach platform of the present invention;

FIG. 12 is a sectional view taken on the line l2-l2 of FIG. 11 and looking in the direction of the arrows to illustrate the axial locking association of the button punch interlock formations of the platform members with the inturned lip of the support rails and the lateral locking association of the inturned lips of the platform members with the opposing wall of the notches formed in the rolled edge of the lower support rail flanges;

FIG. 13 is atop plan view of the novel wide tread, injection molded, plastic ladder steps provided by the present invention to assure ready assembly and final tightening of the round headed securing bolts with the concealed nuts;

FIG. 14 is a front quarter section of the step of FIG. 13 to illustrate the transverse reinforcing rib structure provided between the depending front and rear walls of the step and the thickened vertical reinforcing rib formed along the length of the ladder rail sockets provided at the opposite ends of the steps;

FIG. 15 is a bottom plan view of the ladder step of FIG. 13;

FIG. 16 is an end view as seen from the right end of FIG. 13;

FIG. 17 is a sectional view taken on line 17l7 of FIG. 14 looking in the direction of the arrows; and

FIG. 18 is a sectional view taken on line l8l8 of FIG. 14 looking in the direction of the arrows.

DESCRIPTION OF PREFERRED EMBODIMENT With continued reference to the drawings wherein the same reference numerals are used throughout the several views to indicate the same parts, the play center of the present invention comprises a skeletal main frame 20 made up ofa pair of identical side frame assemblies 21 (FIG. 5), a single cross frame assembly 22 (FIG. 6), a pair of identical end frame assemblies 23 (FIGS. 2, 3 and 7) having ground engaging outboard cross runs stabilizing main frame 20 against endwise tilting, and a reinforcing truss assembly 24 (FIG. 8) forming with the end portions of cross frame assembly 22 in the final assembly of main frame 20 respective oppositely laterally extending, outrigger frame sections stabilizing main frame 20 against sidewise tilting. Assembled main frame 20 is arranged to suspend a swing assembly 30 from the upper cross run of a first end frame assembly 23; to support between the side runs of the second end frame assembly 23 and the adjacently related end runs of the two side frame assemblies 21 a

multiuse platform assemblage

27, 28, serving alternately as a picnic table-bench unit, a crawl through play tunnel, a walk across stile, and a two sided step ladder to gain access to the upper cross run of the other end frame assembly 23 and the adjacently right angularly related upper side frame runs designed for use as a chinning and swing bar and parallel bars for performing gymnastic exercises; to support between the outrigger frame section at one side and the adjacently related runs of a first side frame assembly 21 and the vertical side run of the first end section frame assembly 23 a sliding board approach ladder, approach platform 26, and sliding board 29 assembly; and to support between the vertical runs of the outrigger frame section at the other side staggered wide tread ladder steps 25 alternately used as a ladder to gain access to the upper runs of main frame 20 used as a play lookout tower, tree house or the like with the wide tread steps being also used as seats when playing imaginative games of war, cowboys and indians, forest rangers, and the like. Each of the frame assemblies 21, 22, 23 and 24 are formed of angularly related runs of tubular pipe stock the ends of which are adapted to be telescopically connected and fixedly bolted together by the purchaser so the parts may be boxed and shipped in knocked down form to conserve shipping space and minimize shipping and handling costs. These various units may be selectively dimensioned to serve the needs of children of preschool age or older. In either case the construction of the overall structure as well as the respective frame assemblies will be identical except for pipe stock sizes and dimensions, larger and heavier pipe stock being used in the larger size units to assure adequate strength and safety. The following detailed description will be directed to a preschool age play center the dimensions given being exemplary only.

Referring for the moment to FIG. 5 illustrating in detail one of the two side frame assemblies 21 required, a generally U- shaped ground engaging member 32 having a ground engaging straight run 33 of approximately 11 inches in length and upwardly divergent straight runs 34 of approximately 12% inches in length integrally joined by curved transition sections 35 defining respective included angles of (See angle A) is provided. The upper end of each divergent run 34 is telescoped into a respective long leg 36 of an inverted generally L-shaped member 37 and through bolted thereto as indicated at 38 by a bolt and nut assembly preferably comprising a rounded kerfed bolt head and a cap nut to minimize exposed sharp corners and edges that might scratch and cut the playing children. The short leg 39 of each member 37 defines with its related long leg 36 an included angle of 80 (See angle B) and is integrally joined thereto by a curved transition section 41. The straight run of long legs 36 is roughly 42 inches and the straight run of the short legs 39 is roughly 8 inches. The oppositely inwardly directed short legs 39 telescopically receive the opposite ends of an inverted wide V-shaped cross tubular member 42 defining an included angle of (See angle C) having its inserted ends and the enclosing ends of legs 39 vertically through drilled at 40 (FIG. 5) adapting them to receive bolt and nut assemblies of the type heretofore described. As best seen in FIG. 5, the curved transition section of tubular member 42 is horizontally through drilled at 43 for bolted connection to frame assembly 24 as will be hereinafter described. The straight run 33 of member 32 is also vertically through drilled at 44 midway ofits ends for bolted connection to the ground engagingruns of frame assembly 22 as will presently appear. While the dimensions and angles of side frame assemblies 21 may be varied to provide larger play centers, the dimensions and angles given provide side frame assemblies 21 having an overall height of about 5 feet 2 inches adequate to provide a play center of about 7 feet total height.

Referring next to FIG. 6, illustrating in detail the main frame section 49 ofthe cross frame assembly 22, it will be seen that main frame section 49 is composed of an upper straight run 51 the opposite ends of which are telescoped into the ends of respective right-angled corner members 52 and are through bolted to the horizontal run thereof at 38 by bolt and nut assemblies of the type heretofore described, a pair of respective vertical runs 53 having their upper ends telescoped into the respective vertical runs of corner members 52 to which they are through bolted at 38 to the respective vertical runs of a pair of ground engaging right-angled, corner members 54 as will presently appear. The horizontal runs of members 54 terminate in opposingly spaced free ends 55 which are flattened out, upwardly arched and through drilled vertically adapting them to overly and be through bolted at 38 (FIG. 1) to the midpoint of the ground engaging straight run 33 of the respective side frame assemblies 21 by nut and bolt assemblies of the type previously described in the final assembly of the play center. The upper straight run 51 of the main frame section 49 is horizontally through drilled at 56 at its midpoint adapting it for through bolted connection to the cross truss member of reinforcing truss assembly 24 of FIG. 8 which will be presently described. The horizontal runs of ground engaging corner members 54 are also horizontally through drilled inwardly from free ends 55 at equispaced points 57 adapting the corner members 54 for bolted connection to the ground engaging members of reinforcing truss assembly 24 to be presently described. The upper right end corner member 52 of main frame section 49 is further through drilled at 58 adapting it for bolted connection to the reinforcing truss assembly 24 as will presently appear. The

tubular elements

51 and 53 for the small dimensioned play center here illustrated are respectively given an axial length to assure an overall height of 68 /2 inches and an overall width of 7 feet 2% inches to the main frame section 49 while the ground engaging runs of comer members 54 are of a length to dispose free ends 55 to be connected to side frame runs 33 an equal distance of about 22% inches inwardly of the respective vertical runs 53 of main frame section 49. This dimensioning of main frame section 49 assures an adequate lateral extension of main frame section 49 beyond the side frame assemblies 21 to form outrigger reinforcing frame sections and above the side frame assemblies 21 to respectively resist sidewise tilting of the play center as finally assembled and a truss structure, when assembled with truss assembly 24, that will rigidly support the side frame assemblies 21 in predetermined laterally spaced relation; about 29 inches in the small play center depicted.

Referring now to the truss assembly 24 of FIG. 8, it comprises a pair of identical U-shaped ground engaging members 61 the legs of which extend vertically to respectively receive a pair of equilength vertical runs 62 and a third vertical run 62 and a half length vertical run 63 the lower ends of which telescope into legs of the respective ground engaging members of upper straight run 51 will align with drilled passage 57 in the straight run 67 of cross truss member 65 enabling the run 51 and truss member to be through bolted together as indicated at 38 in FIGS. 1, 2, and 3. At the same time the inner most through drilled passages in the horizontal run of corner members 52 will align with the through drilled openings 57 in the telescoped ends of innermost runs 62 and dependent truss member legs 64 enabling these three parts to be through bolted together at 38 as indicated in FIGS. 1, 2, and 3 to complete cross frame assembly 22. It will be appreciated from the preceding description, that the lateral outrigger ends of cross frame assembly 22 constitute rigid reinforced end sections interconnected by an equally rigid cross run 51 as a result of the three bolted connections of truss member 65 and the bolted interconnection of cross run 51 and the outermost full height vertical run 62 as seen at the right side of FIGS. 1 and 2.

This reinforcing cross frame assembly 22 is then raised to its upstanding position as seen in FIGS. 1, 2 and 3 and the side frame assemblies 21 previously described are then respectively set in position with ground engaging runs 33 beneath the arched ends 55 ofcorner members 54 and the midpoint of side frame cross tubular member 42 crossing and abutting the inner face of the respective innermost vertical runs 62 of truss assembly 24 which are through drilled at the point of cross adapting the cross tubular member to be through bolted thereto as indicated at 38 in FIGS. 1, 2 and 3. The free ends of 61 and are through bolted thereto as indicated at 38 by nut and bolt assemblies of the type heretofore described. Truss assembly 24 is completed by telescoping the ends of respective ladder steps 25 onto vertical runs 6262 in laterally staggered, vertically spaced relation and to vertical runs 62-63 in laterally staggered, vertically spaced relation as depicted in FIG. 8 and telescopically inserting the upper ends of the innermost vertical runs 62 into the dependent legs 64 of a cross truss member 65 and through bolting the telescoped ends thereto as will presently be pointed out. Preferably the steps are through bolted in their final vertical locations by nut and bolt assemblies 60 entered through laterally aligned passages 57 formed in the lower ends of steps 25 and vertical runs 6263 as shown in FIG. 14. Each of the ground engaging members 61 are through drilled at 57 at laterally spaced intervals to match the through drilled openings 57 of the ground engaging members 54 of main frame section 49, which are preferably through bolted to members 61 prior to assembly of vertical runs 57 of the main frame section 49 as shown in dotdash lines in FIG. 8. Cross truss member 65 is formed with downwardly and inwardly inclined runs 66 defining with the dependent legs 64 an included acute angle having their lower ends integrally joined with a straight cross run 67 through drilled midway of its length at 57 for a purpose to be presently pointed out. The included angle defined by runs 66 and the length of runs 66 and vertical runs 62 are so chosen as to assure that straight run 67 will lie in adjacent side-by-side relation to upper straight run 51 of main frame section 49 upon completing the cross frame assembly 22 as will now be described.

Partially assembled main frame section 49 (lacking comer member 54 previously through bolted to members 60 of truss assembly 24) is assembled with truss assembly 24 by entering the lower ends of runs 53 through the free ends of the outermost laterally outwardly disposed steps 25 and inserted into the upstanding legs of the respective corner members 54 and through bolted thereto at 38 (See FIG. I and 6). In this partially assembled relation the center through drilled passage 56 arched ends 55 of corner members 55 are then through bolted to the respective runs 33 of the side frame assemblies 21 as indicated at 38 in FIG. 1 to complete the assembly of side frame assemblies 21 and cross frame assembly 22.

Side frame spacer struts 71 having flattened and upwardly arched ends 55 are then through bolted at 38 respectively to cross tubular member 42 using the vertical through drilled passages 72 (FIG. 5) and the through drilled ends 55 of struts 71 to fix the lateral spacing of the side frame assemblies 21.

Further fixing of the spacing of side frame assemblies 21 and rigidification of the side frame assemblies is effected by the pair of end frame assemblies 23 (FIG. 7) which will now be described in detail. These end frame assemblies are of identical constructure and each comprise a U-shaped ground engaging member 75, an upper U-shaped crossmember 76 and a pair of wide V-shaped tubular side runs 77 defining an included angle of about The leg portions 78 of the U- shaped

members

75 and 76 telescope into the opposite ends of the side tubular runs 77 and are respectively through bolted together, the legs of member 75 at the right end being through bolted together as indicated at 38 in FIGS. 1 and 7.

U-shaped members

75 and 76 are designed so that their respective legs will be spaced apart about 29 inches adapting them to impart to side tubular runs 77 a relative lateral spacing equal to that of the side frame assemblies previously described. The straight run 79 of each side tubular run 77 is about 2 feet in length while the upper straight run 81 of each side tubular member 77 is about I4 inches thereby assuring that the ground engaging straight run of each member 75 will be offset outwardly beyond the straight run of its associated upper crossmember 76 as indicated by the dot-dash line 82 of FIG. 7 for a purpose to be presently pointed out.

Each of the straight runs 81, about I inch and about 10 inches inwardly from its free end, is through drilled in the plane defined by the axes of its respective straight runs 79 and 81 to mate with similarly spaced drilled passages provided in the straight runs 36 of side frame assemblies 21 adjacent their inner ends adapting the side tubular runs 77 to be through bolted at spaced points 38 (FIGS. 1, 2, and 3) to under sides of the runs 36 of side frame assemblies 21. The upper bolted connection in each case also secures the telescoped ends of side tubular runs 77 to the associated leg portions 78 of upper crossmember 76. This bolted connection of end frame assemblies 23 with side frame assemblies 21 disposes runs 79 and 36 of the respective end frame assemblies and side frame assemblies in downward divergent relation as best shown in FIG. 1

It will be appreciated from the preceding description that the play center frame 20 in its assembled condition not only delimits a play area on the ground or other support surface but defines skeletal side and sloping top walls defining a play space above the ground play area which can, by use of suitable cover and wall materials, such as canvas or plastic sheeting, form a play house when desired. At the same time this skeletal frame 20 provides a stable, tilt resisting, support structure capable of use as a climbing and gymnastic workout structure, as a lookout or ranger tower and as a support for swings, a sliding board, a picnic table and bench set which also provides a stilelike step ladder and crawl tunnel, and many other play activities which the imaginative child will conceive.

To provide these further play activities, the present inven tion contemplates that the steps 25 be of unique construction to serve as seats as well as steps, that the upper cross member 76 of the end frame assemblies be formed to fixedly support strap or ropelike swing supports, that one of the outrigger sections providing steps for the full height provide a ladder for climbing or access to the top of the structure, that the other outrigger section providing steps for half the height provide an access ladder to slide approach platform and slide fixedly mounted to the outrigger structure and adjacently related outer sides of the side and one end frame assembly to serve also as a counterbalancing weight to resist tilting forces due to use of the crossbar of the opposite end assembly as a chinning and swing bar, and that the area defined by the divergent runs of the other end frame assembly and the adjacently related ends of the side frame assemblies provide a support for tablebench platform structures which provide a crawl through tunnel, a stilelike step ladder providing access to the crossbar of the other end frame assembly, and a counterbalancing weight to resist tilting forces due to use of the swing suspended from the upper crossbar of the opposite end frame assembly as well as a picnic table and benches. FIG. 1 depicting a group ofchil dren turned loose and unobtrusively photographed while using the play center of this invention clearly illustrates some of the innovative play activity engendered by this invention.

Referring for the moment to FIGS. 9 and 10 of the drawings, there are illustrated in cross section two similar swing suspension structures which this invention contemplates. In both cases, the sectioned tubular member 91 comprises the straight upper cross run of one of the crossmembers 76 of an end frame assembly 23. Tubular crossmember 91 at laterally spaced points 92 (See FIG. 3) is through drilled at 93 through the upper wall only (FIG. 9) and through drilled outwardly from passages 93 through both walls to from aligned passages 94 (FIG. 9) adapted to freely pass the straight shank 95 ofa rodlike L-bolt the shank end 96 of which is threaded to receive a nut 97, preferably a domed nut to house the sharp thread edges. The free head end of the L-bolts is provided with a dependent lug 100 fitted into the passages 93 to fix the bolt head against lateral movement relative to crossmember 91. The swing suspension member, a straplike fabric member, providing an attachment loop 98 by stitching its turned back free end crosswise at 99 to an axially spaced area, is tclcscoped over the free ends of crossmember 91 before the end frame assembly 21 is assembled. After assembly, the loop 98 is positioned in overlying encircling relation to the portion of crossmember 9| lying between

passages

93 and 94 and the shank 95 of thc l.-holt is passed through passages 94 to dispose the rodlike head I01 in overlying clamping relation to the loop 98. Upon applying nut 97 and threading it home, head 101 will be drawn tightly down upon the underlying portion of loop 98 clamping the loop portion between the covered portion of crossmember 91 and head 101. Since all surfaces contacting the fabric loop 98 are smooth and rounded and of substantial area, the clamped section of loop 98 will be firmly fixed against both axial and rotational movement relative to tubular member 91 and swinging will merely flex the free portions of the straplike members back and forth. Little or no wear will be experienced assuring a long useful life of the suspension strap.

The structure of FIG. 10 is substantially the same and the common parts have, therefore, been given the same reference number. The sole difference is that tubular member 91 is drilled to form an entrance passage 94 through the upper wall and the exit passage 94 in the lower wall is through drilled midway between recess 93 and entrance passage 94 to provide a slightly elongatedpassage 102 and shank 95 is bent inwardly at 103 and then return bent at 104 to dispose its threaded shank end 96 in laterally centered relation to rodlike head 101. In this form of the invention, the shank 95 is threaded through passage 94 then canted to pass its thread shank end 96 into and through elongated passage 102 until the L-bolt assumes the position shown in FIG. 10. This construction places the nut 97 in housed relation between the two open sides of loop 98 minimizing the possibility ofinjury should a child hang by his hands from and swing on tubular member 91 or in playing passes his head under crossmember 91 near loop 98.

Referring now to FIGS. 13 and 18, detailing the ladder steps or rungs 25 designed for use as seats as well as ladder steps or rungs, each step 25 comprises a one piece injection molded structure designed to provide a tread plate 111 of maximum width (2% inches) along its lateral center tapering toward its opposite ends where it merges into the top ends of right angularly related, dependent, elongated, sleevelike, tubular mounting formations 112 having peripheral curved sidewalls 113 (FIG. 13) comprising arcs of a circle having a radius of 9/16 inches into which the tread plate edges merge at a tangent, This unique tread plate shape provides a central seating area of substantial width flanked on either side-by-step areas 114 (FIG. 13) of reduced width disposed adjacent the mounting formations 112 which are conveniently disposed (See FIG. 2) for use as stepping areas in ascending and descending using either the

center run

62 or 63 or adjacently related runs 62- 62, 62-53, 63-62, or 63-53 as hand hold ladder rails.

Tread plate 111 is rigidified by the provision of integrally formed depending skirts 115 along the edges of tread plate 111 merging tangentially at their opposite ends into curved sidewalls 113 of mounting formations 112 as indicated at 116 in FIG. 15 and respective axially spaced pairs of crosswebs 117 equidistantly spaced from the midpoint of treadplate 111 and crosswebs I18 equidistantly spaced from crosswebs 117 as best seen in FIG. 14 and 15.

The outer wall face of each mounting formation 112 lying between the outer ends of dependent skirts 115 is provided with a full length thickened rib 119 providing a flat face 121 for abutting contact with the securing nut of nut and bolt assembly 60 while the opposing outer wall face in surrounding relation to the through aperture 57 is provided with a thickened boss 122 providing a similar flat face 121 for abutting contact with the opposing flat face of the bolt head of nut and bolt assembly 60. As a result of this rib and boss construction a wide gripping area of the tubular runs 62, 63, 53 underlying the bolt head and nut is assured when the bolt and nut assembly is tightened thereby positively fixing each step or rung 25 in its selected vertically spaced relation. Preferably, the upper face of tread plate 111 as its center is formed with a depressed recess [23 for receiving the manufacturer's trademark or like identification (not shown) and the area outside of rcccss 123 is formed with a hohnail tread I24 (FIGS. [3 and I4) to nssurc a nonslip tread surface. The lower edge of skirts [I5 is thickened at the center and to a progressively lesser degree outwardly toward each end as indicated at 125 (FIGS. 13, I6, 17, and 18) to better resist sidewise blows from the childrens feet when using the steps or rungs 25 as a ladder.

While the slide board approach platform 26 and table and

bench seat platforms

27 and 28, may be variously constructed, the present invention contemplates a novel construction which may be preassembled without the need of separablel fastener elements for unitary installation. While this novel platform structure is here shown for use in providing slide approach platform 26, table platform 27 and bench seat plat- 1 for home yard, and porch gliders, for bench seats designed for general'use, and for picnic and table structures of general utility.

As will appear from a consideration of FIGS. 11 and 12 of the drawings detailing the table platform 27, each platform comprises a pair of identical platform support channels 131 and a pair of platform channels 132, which, in the case larger surface areas or abutting surface areas are desired, can be multiplied as desired.

Referring for the moment to support channels 131, each support channel comprises a channel member of a preselected length comprising a pair of spaced

flanges

133 and 134 interconnected along adjacently related sides by an integrally formed web 135 through drilled at 136 adjacent the opposite ends adapting support channel 131 for bolted connection at 38 (FIG. 1) to frame runs 36, 79 in the case of

platforms

27 and 28 and to runs 53, 62 and the slide board hand and support rails 137 in the case of platform 26. Through drilled openings 136 will be omitted, of course, in cases where such a bolted connection is not required or will be relocated in other selected locations along web 135 where a different bolted connection is required.

As best seen in FIG. 11, the free ends of

flanges

133 and 134 terminate in vertically spaced aligned relation and are respectively provided with an inturned, slightly spaced, return bent lip 138 and an inturned rolled lip 139. Rolled lip 139 is suitably notched at longitudinally spaced intervals as indicated at 141 or a double width notch as indicated at 142 in place of the two inner notches 14-1 for a purpose to be presently pointed out.

Still referring to FIG. 11, platform channels 132 each comprise a channel member of a preselected length comprising a pair of spaced

flanges

143 and 144 interconnected by a wide web 145 the center areas of which may, if desired, be embossed as indicated at 146. The free ends of

flanges

143 and 144 are provided with an inturned, slightly spaced, return bent lip 147 the thickness and spacing of which is designed together with the thickness of the respective flanges to freely fit within the notches 141 of support channels 131 as shown in FIG. 12 with the outer flange faces lightly abutting the opposing notch edges thereby fixing the platform channels against lateral shifting movement relative to support channels 131. In event a solid platform surface area rather than a divided platform surface area is desired then a pair of platform channels 132 having respectively wider webs 145 would be selected so the adjacently related faces of

flanges

143 and 144 could be face butted in notch 142 as shown in dot-dash lines in FIG. 12. Webs 145 at laterally spaced points inwardly from their opposite ends are likewise button punched as indicated at 148 to form upstanding interlock formations providing an upwardly semispherical wall facing toward the respective opposite ends of web 145 and a diametrically laterally disposed abutment edge 149 facing toward the center of webs 145. The inward spacing of these button punched interlock formations 148 is preselected so that the axial distance of abutment edges 149 inwardly from the adjacently related ends of webs 143 will approximate but not exceed the distance between the inner face of webs 135 and the inturned free edge of lips 138 of support channels 131. This is done so that axial insertion of the respective ends of webs 145 into

notches

141 or 141 and 142 of the respective support channels 131 will result in a momentary camming engagement between the semispherical wall of the interlock formations and the opposing surfaces of lips 138 raising lip 138 toward its support flange 133 followed by a snapping back oflip 138 to its normal spaced position as abutment edges 149 pass inwardly of the free edge of lip 138. Once this insertion is made axial retracting movement of the platformchannels 132 from support channels 131 can be accomplished only by destructive deformation of the portions of lip 138 in the area of the interlock formations. It follows, therefore, that a permanent interlocked assembly of the support channels 131 and platform channels 132 is assured by this novel platform construction without the aid of separable fasteners.

Once the preassembly of

platforms

26, 27 and 28 is effected, these respective platforms are assembled as a unit onto skeletal frame 20 by through bolting their respective support channel ends as shown at 38 in FIG. 1 to frame runs 53 and 62 in the case of platform 26 with the upper end of frame run 63. which is flattened out as shown at 150 (FIG. 8), adapting it to be abuttingly clamped behind the adjacently related dependent flange 143 of the end mounted platform channel 132 as shown in FIG. 1 and to frame runs 36 and 79 as shown at 38 in the case of

platforms

27 and 28 as also shown in FIG. 1. The opposite end of slide approach platform 26 together with the upper end of slide board 29 are then through bolted to the straight runs 151 of hand rails 137 as shown at 38 in FIG, 1. The upper ends of the return bent runs 152 of hand rails 137 are then through bolted as shown at 38 in FIG. 1 to frame runs 53 and 62 in vertically spaced crossing relative above platform 26 while the lower ends of straight runs 153 of hand rails 137 are through bolted to frame runs 53 and 62 in cross relation at 38 using the same bolt and nut assemblies used to secure the telescoped ends of

runs

53 and 62 to the upstanding legs of the adjacent frame corner members 54 and adjacent U-shaped member 61 as seen at the lower right corner of FIG. 3. The lower end of slide board 29 is supported in spaced relation to the ground or other support surface by U-shaped support member 154 the upper leg ends of which are bent over and telescoped into the rolled slide board side rails 155.

The exposed ends of support channels 131 are preferably fitted with triangularly shaped, plastic, protective cups 159 the walls 161 of which are through drilled at 162 to align with passages 136 of support channels 131 adapting the caps to be fixed in place with walls 161 clamped between the channel webs and the opposing frame runs to which they are boltedv Similar protection is provided for the free ends of crossing tubular runs by cylindrical plastic cup members 163 (FIG. 1).

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

l. A play center for preschool and grade school age children designed to encourage innovative play activity comprising a tubular skeletal structure composed of respective pairs of side and end frame assemblies each formed of interconnected tu bular support runs, upstanding end runs, and top cross runs defining closed skeletal shapes; means respectively interconnecting said frame assemblies to define a generally rectangular skeletal frame structure delimiting a play area wherein said end frame assembly support runs are outwardly offset beyond the ends to stabilize the play center against end tilting in use; a cross frame assembly disposed substantially midway of said side frame assemblies and having an upper cross run and oppositely extending end sections disposed laterally outwardly of said side frames including inwardly directed support runs terminating at and fixedly connected to said side frame support runs and laterally spaced vertical runs disposed outwardly of said respective side frame assemblies and extending upwardly from said inwardly directed support runs and fixedly connected to said cross frame upper cross run; means fixedlyiinterconnecting said laterally spaced vertical runs at said respec tive ends of said cross frame assembly comprising vertically spaced ladder rungs, said ladder rungs at one side extending the full height of said cross frame assembly to provide access to the top of said play center and provide a climber section and said ladder rungs at said other side extending about onehalf the height of said cross frame assembly to provide access to a point midway of the height of said play center, and means fixedly connecting said innermost vertical run at each end of said cross frame assembly to a respective side frame upper cross run to rigidify said laterally outwardly disposed ends of said cross frame assembly and stabilize the play center against side tilting in use; slide board means including a slide board and a slide approach platform extending longitudinally of said other side of said play center toward one end of said play center, said slide approach platform having one end fixed to said laterally spaced vertical runs and platform hand rails fixed to said laterally spaced vertical runs at said other side and to the adjacently related upstanding runs of said end assembly at said one end of said play center and means fixedly connecting said hand rails to said slide approach platform to support the other end of said slide approach platform and the upper end of said slide board of said slide board means; a swing suspended from the top cross run of said one end of said play center; an upper table platform and a pair of lower bench seat platforms providing a bench seat alongside of and below each edge of said table platform respectively; means fixedly connecting said table platform and said pair of bench seat platforms in vertically spaced relation to the upstanding end runs of the other end section and the adjacently related upstanding end runs of said side frame assemblies, the space between said bench seats and below said table platform providing an open ended crawl tunnel passage.

2. The play center of claim 1 wherein said cross frame assembly upper cross run is provided with a laterally directed truss member having dependent end runs telescopically associated with the adjacently related, innermost vertical runs of said cross frame assembly and downwardly and inwardly inclined runs integrally joined at their inner lower ends to a laterally directed run fixedly connected to the midpoint of said upper cross run of said cross frame assembly to strengthen said cross frame assembly adapting it to resist compression forces transmitted to said upper tubular cross run in use of the play center.

3. The play center of claim 1 wherein each of said ladder rungs comprises an injection molded plastic member comprising an elongated planar tread plate having dependent skirt portions along its opposite longitudinal edges interconnected at equispaced points at opposite sidesofits longitudinal center by integral, laterally directed reinforcing webs and said tread plate is formed at its opposite ends with integrally formed, dependent annular sleeve members diametrically end notched at their lower ends in alignment with the longitudinal axis of the tread plate, the outer wall surfaces of said sleeve member being formed to merge smoothly into the outer faces of said dependent skirts and the inner wall surface of which lying between the skirt ends is thickened throughout its length at opposite sides of said longitudinal axis to reinforce the line of juncture between each sleeve member and the tread plate and to provide a tangential fiat face providing full bearing engagement with the abutment faces of the nuts of nut and bolt assemblies provided to fixedly connect the respective sleeve members in selected vertical position along the respective vertical runs assembled in the respective sleeve through bores.

4. The play center of claim 3 wherein the outer face of each sleeve member in surrounding relation to the notch in its lower end is thickened to provide a tangential flat face segment providing full bearing engagement with the abutment face ofthe bolt head ofsaid nut and bolt assemblies.

5. The play center of claim 1 wherein the top cross run of said one of said end frame assemblies at equispaced distances from its opposite ends is provided with a through aperture dimensioned to freely pass the shank of an L-bolt and the upper wall only in axially spaced relation to said through aperture is through drilled to form an L-bolt locking passage, said suspended swing includes a pair of straplike suspension members formed at their upper ends with loops positioned to encircle said top cross run in overlying relation between said through passage and said locking passage, and said L-bolts have dependent locking lugs disposed to enter said locking passages and threaded shank ends inserted through said through apertures to dispose the elongated head of said L-bolt in overlying relation to said positioned strap loops and are provided with securing nuts which, when tightened, draw said elongated heads firmly against said overlying portions of said loops forcing said portions of said loops into clamped engagement with said top cross run thereby fixing said loops against axial and rotational movement relative to said top cross run.

6. The play center of claim 5 wherein said L-bolt shank between said threaded shank end and said elongated head is bent inwardly at its juncture with said elongated head at an acute angle and then reversely bent to dispose its threaded shank end in centered axial relation to said elongated head and said through aperture in said top cross run is formed by an entry end and an exit end offset in the direction of said locking passage to dispose said threaded shank end in coaxial relation to the longitudinal center of said elongated head whereby the securing nuts will be disposed approximately midway between the edges of said straplike suspension members so as to be housed by the loop to prevent accidental contact of playing children with the nut.

7. The play center of claim 1 wherein said slide approach platform, said table platform and said bench seat platform each comprise a pair of support channel members disposed in laterally spaced relation with their channel openings in opposed facing relation and delimited along their upper edges by an inturned lip and delimited along their lower edges by an inturned lip having longitudinally spaced notches cut therein at predetermined intervals and a plurality of platform channel members disposed in preselected spaced relation lengthwise of said support channel members with their channel openings facing downwardly, the ends of their web portions formed with laterally spaced, upwardly directed button punches engaged behind the inturned lip delimiting the upper edges of the channel openings of said support channel members to fix said platform channels against axial withdrawal from said opposed support channel members, and their dependent channel forming flanges disposed in preselected spaced notches of said support channels to fix said platform channel members against relative movement axially ofsaid support channel members.

8. The play center of claim 7 wherein the web portion of each of said support channel members adjacent its opposite ends is formed with a bolt passage adapting said support channel members for selective bolted connection to the respective upstanding runs of said end frame assemblies at said other end of said play center and to the respective adjacently related upstanding runs of said side frame assemblies.

9. The play center of claim 8 wherein the platform channel members of said slide approach platform and said table platform are disposed in close side-by-side relation adjacent the longitudinal center of said channel support members and the platform channel members of said bench seat platform are disposed in widely spaced relation adjacent the opposing ends of said channel support members to properly relate the seats to the table platform.

10. The play center of claim I wherein said side frame assemblies are each composed of a support run having upwardly and outwardly inclined ends, a pair of upstanding side members having a straight run telescopically fitted to and bolted to the upwardly and outwardly inclined ends of said support run and an inturned upper end lying in the plane defined by said support run and said straight run and a wide inverted V- shaped run telescopically fitted to and bolted to the inturned upper ends of said side members and said end frame assemblies each comprise respective U-shaped support runs the ends of which are inclined upwardly and toward the respective opposed ends of said side frame assemblies, a pair of upstandthan its associated straight tubular run, and a U-shaped top cross run having its end portions telescopically fitted to and bolted to the return bent upper ends of said related pairs of upstanding members.

UNITED STATES [PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,601, 397 Dated Aug. 24, 1971 Inventor(s) Edward T. Carlin Bobbie L. White It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 74, change "Uhaped" to --U-shaped.

Column 4, line 67, insert after 38 -by similar nut bolt and nut assemblies and having their lower ends adapted to be telescoped into and through bolted at 38-.

Column 7, line 55, change "from" to --form-.

Column 8, line 60, change "of" to --on-.

Column 8, line 64, change "as" to -at-.

Column 10, line 25, change "relative" to --relation--.

Signed and sealed this 18th day of April 1972.

(Sl-JAL) Attest:

EDWARD I LFLETCIIER ,JR. ROBERT GOTTSCHALK At testing Officer Commi ssioner of Patents USCOMM-DC 50376-1 69 ORM POJOSO (10-69! u s. sovsnumzu'r Pmrmucornc: I959 o-see-saa

Claims

1. A play center for preschool and grade school age children designed to encourage innovative play activity comprising a tubular skeletal structure composed of respective pairs of side and end frame assemblies each formed of interconnected tubular support runs, upstanding end runs, and top cross runs defining closed skeletal shapes; means respectively interconnecting said frame assemblies to define a generally rectangular skeletal frame structure delimiting a play area wherein said end frame assembly support runs are outwardly offset beyond the ends to stabilize the play center against end tilting in use; a cross frame assembly disposed substantially midway of said side frame assemblies and having an upper cross run and oppositely extending end sections disposed laterally outwardly of said side frames including inwardly directed support runs terminating at and fixedly connected to said side frame support runs and lAterally spaced vertical runs disposed outwardly of said respective side frame assemblies and extending upwardly from said inwardly directed support runs and fixedly connected to said cross frame upper cross run; means fixedly interconnecting said laterally spaced vertical runs at said respective ends of said cross frame assembly comprising vertically spaced ladder rungs, said ladder rungs at one side extending the full height of said cross frame assembly to provide access to the top of said play center and provide a climber section and said ladder rungs at said other side extending about one-half the height of said cross frame assembly to provide access to a point midway of the height of said play center, and means fixedly connecting said innermost vertical run at each end of said cross frame assembly to a respective side frame upper cross run to rigidify said laterally outwardly disposed ends of said cross frame assembly and stabilize the play center against side tilting in use; slide board means including a slide board and a slide approach platform extending longitudinally of said other side of said play center toward one end of said play center, said slide approach platform having one end fixed to said laterally spaced vertical runs and platform hand rails fixed to said laterally spaced vertical runs at said other side and to the adjacently related upstanding runs of said end assembly at said one end of said play center and means fixedly connecting said hand rails to said slide approach platform to support the other end of said slide approach platform and the upper end of said slide board of said slide board means; a swing suspended from the top cross run of said one end of said play center; an upper table platform and a pair of lower bench seat platforms providing a bench seat alongside of and below each edge of said table platform respectively; means fixedly connecting said table platform and said pair of bench seat platforms in vertically spaced relation to the upstanding end runs of the other end section and the adjacently related upstanding end runs of said side frame assemblies, the space between said bench seats and below said table platform providing an open ended crawl tunnel passage.

3. The play center of claim 1 wherein each of said ladder rungs comprises an injection molded plastic member comprising an elongated planar tread plate having dependent skirt portions along its opposite longitudinal edges interconnected at equispaced points at opposite sides of its longitudinal center by integral, laterally directed reinforcing webs and said tread plate is formed at its opposite ends with integrally formed, dependent annular sleeve members diametrically end notched at their lower ends in alignment with the longitudinal axis of the tread plate, the outer wall surfaces of said sleeve member being formed to merge smoothly into the outer faces of said dependent skirts and the inner wall surface of which lying between the skirt ends is thickened throughout its length at opposite sides of said longitudinal axis to reinforce the line of juncture between each sleeve member and the tread plate and to provide a tangential flat face providing full bearing engagement with the abutment faces of the nuts of nut and bolt assemblies provided to fixedly connect the respective sleeve members in selected vertical position along the respective vertical runs assembled in the respeCtive sleeve through bores.

4. The play center of claim 3 wherein the outer face of each sleeve member in surrounding relation to the notch in its lower end is thickened to provide a tangential flat face segment providing full bearing engagement with the abutment face of the bolt head of said nut and bolt assemblies.

7. The play center of claim 1 wherein said slide approach platform, said table platform and said bench seat platform each comprise a pair of support channel members disposed in laterally spaced relation with their channel openings in opposed facing relation and delimited along their upper edges by an inturned lip and delimited along their lower edges by an inturned lip having longitudinally spaced notches cut therein at predetermined intervals and a plurality of platform channel members disposed in preselected spaced relation lengthwise of said support channel members with their channel openings facing downwardly, the ends of their web portions formed with laterally spaced, upwardly directed button punches engaged behind the inturned lip delimiting the upper edges of the channel openings of said support channel members to fix said platform channels against axial withdrawal from said opposed support channel members, and their dependent channel forming flanges disposed in preselected spaced notches of said support channels to fix said platform channel members against relative movement axially of said support channel members.

10. The play center of claim 1 wherein said side frame assemblies are each composed of a support run having upwardly and outwardly inclined ends, a pair of upstanding side members having a straight run telescopically fitted to and bolted to the upwardly and outwardly inclined ends of said support run and an inturned upper end lying in the plane defined by said support run and said straight run and a wide inverted V-shaped run telescopically fitted to and bolted to the inturned upper ends of said side members and said end frame assemblies each comprise respective U-shaped support runs the ends of which are inclined upwardly and toward the respective opposed ends of said side frame assemblies, a pair of upstanding members having a straight tubular run telescopically fitted to and bolted to the respective upstanding inclined ends of said support runs and a return bent upper end angled to abuttingly engage and be bolted to the underside of the opposing straight tubular runs of said respective side frame assemblies, said end frame return bent run being shorter in length than its associated straight tubular run, and a U-shaped top cross run having its end portions telescopically fitted to and bolted to the return bent upper ends of said related pairs of upstanding members.