US 3831936 A
A trampoline frame formed of a plurality of frame members formed of lengths of U-shaped tubular metallic pipe disposed with the bases of each length extending in continuous end to end relationship in the same plane and with legs of each length depending in contiguous parallelism. A U-shaped connector is driven into the lower ends of the legs to connect the latter and means are provided for preventing relative lateral movement of upper ends of the legs so as to prevent separation of frame members under load.
Description (OCR text may contain errors)
UnitedStates Patent 1191 Watson et al.
[111 3,831,936 1451 Aug. 27, 1974 1 TRAMPOLINE FRAME  Inventors: John Samuel Watson; Richard John Watson; Robert Gordon Watson, all of 2454 W. 13th Ave., Vancouver, British Columbia, Canada  Filed: June 11, 1973 21 Appl. No.: 368,574
 US. Cl 272/65, 5/114  Int. Cl A63b 5/18  Field of Search 5/114, 127, 129,111;
 References Cited UNITED STATES PATENTS 2,613,957 10/1952 Ritter 108/153 X 2,709.830 6/1955 Becker 285/188 X 3,495,794 2/1970 Polk 272/52 X FOREIGN PATENTS OR APPLICATIONS Great Britain 47/45 UX Primary Examiner-Richard C. Pinkham Assistant Examiner-Joseph R. Taylor Attorney, Agent, or FirmCarver and Company ABSTRACT A trampoline frame formed of a plurality of frame members formed of lengths of U-shaped tubular metallic pipe disposed with the bases of each length extending in continuous end to end relationship in the same plane and with legs of each length depending in contiguous parallelism. A U-shaped connector is driven into the lower ends of the legs to connect the latter and means are provided for preventing relative lateral movement of upper ends of the legs so as to prevent separation of frame members under load.
1 Claim, 4 Drawing Figures TRAMPOLINE FRAME BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to light supporting frames and in particular, but not restricted to trampoline frames.
2. Prior Art Trampolines which have long been used by professional acrobats, schools and gymnasiums have normally been cumbersome and expensive of construction. Trampolines of this type are not so constructed as to render them amenable for easy and quick assembly and disassembly.
In recent years, in order to make the trampolines available to the average home owner who might set up the trampoline in a relatively open space such as a lawn or the like trampoline frames have been devised to permit easy and quick assembly and to render the trampolines amenable to storage when this use is not required.
Knockdown trampoline frames, in the main, have usually been constructed to provide for telescopic joining of the frame members and as such have required tubes of different diameters and a certain amount of welding. Under heavy usage the frame members very often bend and are sometimes compressed out of round sufficiently to hinder and sometimes prevent assembly and disassembly of the various frame components.
Furthermore as the side frame members cannot be crossbraced beneath the trampoline mat such members, in order to reduce failure under heavy loads imposed by users of the trampolines, must be of relatively heavy construction which adds to weight and construction costs.
SUMMARY OF THE INVENTION The present invention provides a knockdown or readily demountable trampoline frame which does not rely on telescopic union of its various parts so that regardless of damage to the various parts, assembly and disassembly poses little problems.
The trampoline frame of the present invention, furthermore, breaks down into sections, the shape of each of which provides ease of transportation and storage thus rendering the trampoline highly acceptable for home use where use of the trampoline is only intermittently required.
The trampoline frame of the present invention includes four legs of tubular material each length being U-shaped so as to have an elongated central portion and two downturned legs extending at right angles to said central portion, the lengths being adapted to be arranged in the form of a rectangle with the central portions of the lengths lying in the same plane and adjacent legs of adjacent lengths extending in contiguous parallelism. A U-shaped connector adapted to be driven into open lower ends of the legs prevents separation of said lower ends and means adjacent the upper ends of the legs prevents relative lateral movement of the legs.
A detailed description following related to the drawings, gives exemplification of the apparatus according to the invention which, however, is capable of expression in means other than those particularly described and illustrated.
DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of the trampoline frame of the invention in assembled form, the trampoline mat being shown only partially,
FIG. 2 is an enlarged detail of a pair of adjacent legs, portions being broken away for purposes of clarity of illustration,
FIG. 3 is a section taken on line 3-3 of FIG. 2,
FIG. 4 is a section similar to FIG. 3 showing another embodiment of the invention.
DETAILED DESCRIPTION Referring to the drawings FIG. 11 shows one embodiment 9, of a trampoline frame in accordance with the invention in an assembled condition. The frame, which is substantially rectangular in shape, has four separable frame members 10, 11, 12 and 13. Members 10 and 12 are end frame members and members 11 and 13 are longer side frame members.
Frame member 10 is generally U-shaped having a straight central portion 15 which terminates at its ends in angularly bent corner sections l6l6 which extend at an obtuse angle to the axis of the central section. The corner sections 16-16 themselves terminate in laterally bent leg sections l7--l7 which extend at right angles to both the central section and the corner sections. The leg sections are open at their lower ends l8--l8. The members 11, 12 and 13 are formed in a similar manner to member 10 and. have central, corner and leg sections which have been accorded the same numeral references as their counterparts of frame 10.
As seen in FIG. 1 the frame members are disposed with the central portions 15 of all members in a common plane and with the adjacent legs of adjacent members in contiguous parallelism.
The legs are connected at their lower ends by connectors severally 21. The connectors 21 see FIG. 2, are U-shaped having a flat base 22 from one face of which a pair of dowels 2323 extend. The dowels are adapted to extend into the open ends of a pair of adjacent legs. Diameter of the dowels is such that they have a fit in the legs sufficient to enable the connectors to be easily hammered into place.
A locking tab 26, which is a relatively thick rectangular piece, is welded adjacent one end 27 to each leg adjacent the upper end of the latter. The locking tabs extend tangentially from the legs to which they are attached and over the legs adjacent so as to prohibit relative lateral and rotative movement of the upper ends of the legs.
A trampoline mat 31, which is usually made of a heavy non-stretchable material such as canvas, is sup ported within the rectangular frame by springs or elastic members 33 which extend between the central and corner portions of the frame members and grommeted eyes spaced along the edges of the mat.
ASSEMBLY AND OPERATION In assembling the frame, the frame members are laid on a floor or other flat supporting surface in the form of a rectangle with the legs extending upwards. The connectors are fitted to the legs and driven home by means of a hammer. The assembled frame can then be placed with the bases of the connectors on a firm surface and the mat secured in place.
A user of the trampoline normally bounces in the center of the mat, consequently, in most trampolines bending moment at the center of the longer side frame members corresponding to members 11 and 13, is relatively high. Provision of the corner sections 16 results in a reduction in the overall length of the straight central portion of each of the frame members thus reducing bending moment which enables frame members of smaller than normal cross section to be used, thus decreasing weight and costs.
Furthermore, as the adjacent legs of adjacent members are secured in contiguous parallelism by means of the connectors at the lower ends and the tabs at the upper ends stresses in the legs due to bending moment is low.
FIG. 4 shows a portion of an alternate embodiment 40 of the trampoline. The embodiment 40 is the same in all respects as the embodiment 9 with the exception of the means for preventing relative lateral movement of the legs. In embodiment 40 one of the legs of each of the frame members is shaped so as to provide a longitudinally extending groove 41 which accepts the adjacent leg of the adjacent frame member thus maintaining the legs in contiguous parallelism when the trampoline is used.
It will be appreciated that the frame described can be used for campcots, hospital beds, lounges, supporting structure for above ground swimming pools, etc. where the body supporting material is of a light flexible nature having no inherent rigidity.
1. Frame structure including:
a. four lengths of metal tubing each length being U- shaped so as to have a central portion and a pair of depending legs, the lengths being adapted to be disposed in a substantially rectangular form with the central portions extending in a common plane and with adjacent legs of adjacent members in contiguous parallelism,
b. a U-shaped connector adapted to be driven into lower ends of adjacent legs for preventing separation of said lower ends,
c. means adjacent upper ends of the legs for preventing relative lateral movement of the legs,
(1. the central portion of each frame member being bent adjacent its ends to provide a lateral corner extension extending at an obtuse angle to the central portion so that the central portion of each frame member is shorter than the distance between central portions of adjacent frame members.
=l i l