TRAMPOLINE SUPPORT AND CUSHIONING MEANS
United States Patent 3767009
The outer ends of the coil springs holding the trampoline bed are connected with rods arranged parallel with the edges of the bed so that the springs can automatically adjust their positions to maintain their directions at right angles to the bed, and the supporting rods also are utilized to position the cushions along the side of the bed to keep them from interfering with the springs.
US Patent References:
Trampolines
Grelle et al. - February 1966 - 3233895
Aerial projectile game apparatus with trampoline
Nissen et al. - June 1966 - 3256021
Protective pad and method of forming the same
Mikesell - August 1962 - 3050746
Trampolines
Grelle et al. - February 1966 - 3233895
Aerial projectile game apparatus with trampoline
Nissen et al. - June 1966 - 3256021
Protective pad and method of forming the same
Mikesell - August 1962 - 3050746
Application Number:
05/201376
Publication Date:
10/23/1973
Filing Date:
11/23/1971
View Patent Images:
Export Citation:
Primary Class:
Other Classes:
182/139
International Classes:
A63B5/11; A63B5/00; A62B1/22; A63B5/00
Field of Search:
182/139,138 272/65 5/210,211,233 297/452,DIG.2
Primary Examiner:
Machado, Reinaldo P.
Claims:
I claim
1. A trampoline of the type including a frame, a trampoline bed positioned within said frame, and a plurality of resilient supports stretched between said frame and said bed, wherein the improvement comprises, means for fixedly connecting a first end of each of said resilient supports to the edge of said bed at predetermined intervals, and means for individually slidably connecting a second end of each of said resilient supports to the frame to permit said second end to slide parallel to the frame upon the exertion of a sideward force on portions of the bed by the downward movement of an acrobat thereon, said means for slidably connecting the second ends of the resilient supports comprising at least one rod parallel to the edge of the bed in spaced relationship to the frame and rigidly secured thereto between each of said resilient supports at spaced intervals along said frame, and said resilient supports are provided at said second ends with respective hooks having a diameter larger than the diameter of said rod, said hooks partially surrounding the rod and having a point contact therewith so that said resilient supports will retain positions perpendicular to the edge of the bed.
2. A trampoline as defined in claim 1, wherein said frame comprises a plurality of straight portions angularly related to each other, said means for slidably connecting the second ends of the resilient supports including a plurality of rods parallel to the edge of the bed and secured to the inside of the straight portions of the frame in spaced relationship thereto, each of said rods being partially surrounded by at least one of said hooks.
3. A trampoline as defined in claim 2, wherein the improvement additionally comprises at least one resilient pad mounted on said frame for covering the upper surface of the frame and said resilient supports, and means attached to said pad for releasably engaging said frame and said rods to prevent accidental lifting of the pads and to position them in substantially horizontal position.
4. A trampoline as defined in claim 2, wherein said means for fixedly connecting the first ends of the resilient supports comprises a plurality of anchor rods having a medial loop attached to the trampoline bed along the edge thereof, and respectively connected by said loop to said first ends of the resilient supports.
5. A trampoline as defined in claim 3, wherein the trampoline bed and frame have at least one corner portion, said corner portion being provided with an anchor rod element attached thereto, said anchor rod element comprising two rod portions angularly related to each other and joined by a rounded vertex portion, each of said rod portions having a loop connected to the first ends of the resilient supports attached to the corner portion of the frame.
6. A trampoline as defined in claim 5, having a generally rectangular frame and a rectangular trampoline bed positioned within said frame in spaced relationship thereto, each corner of the bed being provided with an anchor rod element attached thereto, and each side of the frame being provided with a resilient pad having the length of the respective side of the trampoline bed, releasably mounted on said frame and said plurality of rods, and covering the upper surface of the frame and said resilient supports, whereby each corner portion of the frame and the two respective pads define an access opening for the trampoline bed, which is free of sharp-edged elements.
7. A trampoline of the type including a frame, a trampoline bed having at least one corner portion and positioned within said frame, and a plurality of resilient supports stretched between said frame and said bed, wherein the improvement comprises: at least one anchor rod element having two rod portions angularly related to each other and joined by a rounded vertex portion, each of said rod portions having a loop, said anchor rod element being attached to said corner portion of the trampoline bed and said loops being connected to the resilient supports adjacent to the same corner portion of the frame, whereby the corner of the trampoline bed is free of sharp-edged elements.
8. A trampoline as defined in claim 7, comprising a plurality of resilient pads mounted on said frame for covering the upper surface of the frame and said resilient supports, said pads defining respective access openings to the trampoline bed adjacent to each of said corner portions of the bed, whereby said openings are free of sharp-edged elements.
9. A trampoline of the type including a frame structure, a trampoline bed positioned within said frame structure, and a plurality of resilient supports stretched between said frame structure and said bed, wherein the improvement comprises: at least one resilient pad mounted on said frame structure for covering the upper surface of the frame structure and said resilient supports; and means for releasably connecting said pad to said frame structure at points spaced from each other along the length of the frame structure said frame structure comprising a generally tubular frame and at least one bar secured to said frame in spaced relationship thereto, said means for releasably connecting said pad including at least one bracket secured to the pad having a rounded portion partially surrounding the tubular frame and two lips engaging said bar at the opposite sides thereof to prevent the accidental lifting of the pad from the frame structure and to position the pad in substantially spaced relationship to the resilient supports.
10. A trampoline as defined in claim 9, wherein said bar is located at the inside of the tubular frame, and said resilient supports are connected thereto by one of their ends.
11. A trampoline as defined in claim 10, wherein a plurality of straight bars is fixedly secured to the inside of the tubular frame, said brackets engaging said bars, and said resilient supports being individually slidably connected to the same bars to permit said resilient supports to slide parallel to the frame, without contacting the pad, upon the exertion of a sideward force on portions of the bed resulting from downward movement of an acrobat thereon.
1. A trampoline of the type including a frame, a trampoline bed positioned within said frame, and a plurality of resilient supports stretched between said frame and said bed, wherein the improvement comprises, means for fixedly connecting a first end of each of said resilient supports to the edge of said bed at predetermined intervals, and means for individually slidably connecting a second end of each of said resilient supports to the frame to permit said second end to slide parallel to the frame upon the exertion of a sideward force on portions of the bed by the downward movement of an acrobat thereon, said means for slidably connecting the second ends of the resilient supports comprising at least one rod parallel to the edge of the bed in spaced relationship to the frame and rigidly secured thereto between each of said resilient supports at spaced intervals along said frame, and said resilient supports are provided at said second ends with respective hooks having a diameter larger than the diameter of said rod, said hooks partially surrounding the rod and having a point contact therewith so that said resilient supports will retain positions perpendicular to the edge of the bed.
2. A trampoline as defined in claim 1, wherein said frame comprises a plurality of straight portions angularly related to each other, said means for slidably connecting the second ends of the resilient supports including a plurality of rods parallel to the edge of the bed and secured to the inside of the straight portions of the frame in spaced relationship thereto, each of said rods being partially surrounded by at least one of said hooks.
3. A trampoline as defined in claim 2, wherein the improvement additionally comprises at least one resilient pad mounted on said frame for covering the upper surface of the frame and said resilient supports, and means attached to said pad for releasably engaging said frame and said rods to prevent accidental lifting of the pads and to position them in substantially horizontal position.
4. A trampoline as defined in claim 2, wherein said means for fixedly connecting the first ends of the resilient supports comprises a plurality of anchor rods having a medial loop attached to the trampoline bed along the edge thereof, and respectively connected by said loop to said first ends of the resilient supports.
5. A trampoline as defined in claim 3, wherein the trampoline bed and frame have at least one corner portion, said corner portion being provided with an anchor rod element attached thereto, said anchor rod element comprising two rod portions angularly related to each other and joined by a rounded vertex portion, each of said rod portions having a loop connected to the first ends of the resilient supports attached to the corner portion of the frame.
6. A trampoline as defined in claim 5, having a generally rectangular frame and a rectangular trampoline bed positioned within said frame in spaced relationship thereto, each corner of the bed being provided with an anchor rod element attached thereto, and each side of the frame being provided with a resilient pad having the length of the respective side of the trampoline bed, releasably mounted on said frame and said plurality of rods, and covering the upper surface of the frame and said resilient supports, whereby each corner portion of the frame and the two respective pads define an access opening for the trampoline bed, which is free of sharp-edged elements.
7. A trampoline of the type including a frame, a trampoline bed having at least one corner portion and positioned within said frame, and a plurality of resilient supports stretched between said frame and said bed, wherein the improvement comprises: at least one anchor rod element having two rod portions angularly related to each other and joined by a rounded vertex portion, each of said rod portions having a loop, said anchor rod element being attached to said corner portion of the trampoline bed and said loops being connected to the resilient supports adjacent to the same corner portion of the frame, whereby the corner of the trampoline bed is free of sharp-edged elements.
8. A trampoline as defined in claim 7, comprising a plurality of resilient pads mounted on said frame for covering the upper surface of the frame and said resilient supports, said pads defining respective access openings to the trampoline bed adjacent to each of said corner portions of the bed, whereby said openings are free of sharp-edged elements.
9. A trampoline of the type including a frame structure, a trampoline bed positioned within said frame structure, and a plurality of resilient supports stretched between said frame structure and said bed, wherein the improvement comprises: at least one resilient pad mounted on said frame structure for covering the upper surface of the frame structure and said resilient supports; and means for releasably connecting said pad to said frame structure at points spaced from each other along the length of the frame structure said frame structure comprising a generally tubular frame and at least one bar secured to said frame in spaced relationship thereto, said means for releasably connecting said pad including at least one bracket secured to the pad having a rounded portion partially surrounding the tubular frame and two lips engaging said bar at the opposite sides thereof to prevent the accidental lifting of the pad from the frame structure and to position the pad in substantially spaced relationship to the resilient supports.
10. A trampoline as defined in claim 9, wherein said bar is located at the inside of the tubular frame, and said resilient supports are connected thereto by one of their ends.
11. A trampoline as defined in claim 10, wherein a plurality of straight bars is fixedly secured to the inside of the tubular frame, said brackets engaging said bars, and said resilient supports being individually slidably connected to the same bars to permit said resilient supports to slide parallel to the frame, without contacting the pad, upon the exertion of a sideward force on portions of the bed resulting from downward movement of an acrobat thereon.
Description:
The present invention relates to trampolines and, more particularly, to improvements in the construction thereof.
Heretofore, commonly known trampolines have been constructed by tightly stretching a trampoline bed formed of flexible fabric by means of numerous resilient supports, such as coil springs, within a frame formed of rigid material. Usually, these springs are secured, at one of their ends, to loops or holes provided on the frame, and at the other end to anchors attached to the trampoline bed, so that the position of the springs is exactly determined and cannot be individually altered.
In the use of trampolines constructed in this manner, the acrobat often descends on the bed at a location away from the center of the frame toward one end or one side thereof so that his rebound is no longer vertical, and he may even be thrown off of the trampoline by this irregular rebounding action. It has been discovered that this effect is caused by the springs being pulled sideways upon the exertion of a sideways force on portions of the bed by the downward movement of an acrobat thereon, so that the force of the springs does not act perpendicularly upon the edge of the bed and, consequently, produces an irregular rebounding action thereof.
It is, therefore, a main object of this invention to provide a trampoline which always produces a vertical rebound independently from the location at which the acrobat descends on the trampoline bed.
Another object of the invention is to provide a trampoline having a frame and a trampoline bed stretched within the frame by means of a plurality of coil springs, in which the frame and the springs are covered by a protective pad which can easily be removed from the trampoline but which cannot accidentally fall off the same.
Still another object of the invention is to provide a trampoline in which the trampoline bed is formed of conventional fabric sheet which is free of sharp-edged corners.
Other objects and advantages will become apparent from the following detailed description of the invention, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a fragmentary partially broken away plan view of an improved trampoline according to the invention;
FIG. 2 is an enlarged detail plan view of a corner portion of the trampoline bed of FIG. 1;
FIG. 3 is an enlarged fragmentary partially broken away plan view of a side portion of the improved trampoline, showing a variant with respect to FIG. 1;
FIG. 4 is a further enlarged sectional view taken along the line 4--4 in FIG. 3 and showing a pad positioned over the springs secured to the frame means;
FIG. 5 is a further enlarged sectional view taken along the line 5--5 in FIG. 3 and showing the pad mounted on the frame of the trampoline; and
FIG. 6 is a perspective detail view of a bracket used to mount the protective pad on the frame of the improved trampoline.
Referring now more particularly to the drawings, an improved trampoline according to the invention comprises a frame 10 which can have any desired polygonal or even circular shape. According to a preferred embodiment of the invention, however, the frame 10 is of generally rectangular shape and comprises a plurality of straight portions 11 angularly related to each other. Preferably, the frame 10 is formed of a rigid continuous tubular structure, with rounded corner portions 12, but the invention is not limited to this particular feature, since any conventional frame can be used, such as for example a multi-sectional foldable frame.
A trampoline bed 13 having a smaller surface than the area defined by the frame 10 is positioned within the frame and connected to the same by means of a plurality of resilient supports 14, for example coil springs, rubber cables or the like. The bed 13 can be formed of any conventional sheet, but preferably it comprises a flexible fabric sheet having substantially the same proportions as the frame 10 which surrounds the bed in spaced relationship thereto. According to a particularly advantageous feature of the invention, a plurality of fabric strips 15 are doubled over and attached along the edge 16 of the trampoline bed 13, for example by sewing, thus defining a plurality of equidistantly spaced loops 17, as shown in more detail in FIG. 4. A plurality of anchor rods 18, each fashioned integrally from suitable bar stock and having a saddle or loop 19 formed midway therein, have their straight ends inserted into the loops 17 of two adjacent strips 15, thus providing means for fixedly connecting a first end of each of the resilient supports 14 to the edge 16 of bed 13 at predetermined intervals.
One advantage of this arrangement consists in that the strips 15 can be attached to any kind of fabric sheet which need not be formed itself of interwoven spaced strips. Further, the anchor rods 18 provide a firm anchorage for the resilient supports 14 while, at the same time, they do not restrict the flexibility of the edge 16 of the trampoline bed 13.
According to the invention, the frame 10 of the trampoline is provided with means for individually slidably connecting the second end of each of the resilient supports 14 to the frame to permit this second end to slide parallel to the frame 10 upon the exertion of a sideways force on portions of the bed by the downward movement of an acrobat thereon. Consequently, the resilient supports 14 are always individually perpendicular to the edge 16 of the trampoline bed 13 and the rebounding action of the bed is always substantially vertical.
One embodiment of this feature comprises a rod, or bar 20, arranged parallel to the edge 16 of the trampoline bed 13 and fixedly secured to the frame 10 in spaced relationship thereto. Preferably, however, a plurality of rods 20 are secured to the inside of the straight portions 11 of the frame 10 in spaced relationship thereto, for example by means of saddle 21 formed in the rods 20 and welded to the frame 10. These saddles 21 can be provided at any desired intervals along each rod 20, the only condition being that the distance between two adjacent saddles should be large enough to permit unrestricted sliding movement of the hooked portion 22 of the second end of the resilient supports 14. FIG. 1 shows an embodiment in which the distance between two adjacent saddles 21 is designed to receive only one hook 22, whereas FIG. 3 shows an embodiment in which the distance is sufficient to permit the sliding movement of three hooks 22 between two adjacent saddles 21. Each of the hooks 22 has a diameter larger than the diameter of rod 20, so that the hooks have substantially only a point contact therewith in order to reduce friction to a minimum.
Referring particularly to FIGS. 1 and 2, the corner portions of the trampoline bed 13 are provided, according to the invention, with respective anchor rod elements 23 attached thereto and free of sharp edges. Each such anchor rod element 23 comprises two rod portions 24 and 25 angularly related to each other and joined by a rounded vertex portion 26, and each of said rod portions 24 and 25 has a medial saddle or loop 27 and 28, respectively, similar to the loops 19, to be connected with the resilient supports 14 positioned at the corners 12 of the frame. These anchor rod elements have the double purpose of serving as reinforcement for the corner portions of the bed, thus preventing tearing in a diagonal direction, and of providing bed corners which are free of sharp-edged projections, so that an acrobat using the trampoline is not likely to become injured thereby. In addition, the rounded corners of the frame 12, the resilient supports 14 adjacent thereto, and the corners of the bed define respective opening 29 which can be used by children to climb on and off the trampoline bed 13, and the lack of sharp-edged parts prevents the clothes of the children from being torn.
According to a further feature of the invention the improved trampoline is provided with at least one resilient pad 30 mounted on frame 10 for covering the upper surface of the frame 10 and the resilient supports 14. Preferably, each straight section 11 of the frame is provided with such a resilient pad 30 which is generally coextensive in length thereto, in order not to cover the access openings 29. In general, each protective pad 30 comprises an elongated and preferably generally rectangular shaped body 31 having flat exterior surfaces, and the resilient material utilized is preferably sponge rubber or polyethylene foam. It has also been found desirable to cover the exterior of the body with a sheet 33 of weather resistant fabric such as knit cotton sheet covered with a vinyl plastic.
One or more mounting brackets 32 are secured to the body and adapted to releasably connect the pad 30 to the frame structure 10 at points spaced from each other along the length of the frame structure in a manner to prevent the accidental lifting of the pad 30 from the frame structure 10 and to position the pad in substantially horizontal position and in spaced relationship to the resilient supports 14 to permit a free sliding movement thereof.
Each mounting bracket 32, shown in detail in FIG. 6, is formed from a flat strip of rigid metal, bent to form a rounded, substantially semicircular portion 34 integral with a flat lower lip 35 extending outwardly in a substantially radial direction with respect to the portion 34. A flat upper lip 36 is partially punched out from the rounded portion 34 and extends outwardly from said portion in parallel spaced relationship to the lower lip 35. The diameter of the rounded portion 34 corresponds to the diameter of the tubular frame 10, and the space between the lips 35 and 36 is substantially the same as the diameter of rod or bar 20. In the operative position of the bracket, as shown in FIG. 5, the rounded portion 34 partially surrounds the tubular frame 10, and the lips 35 and 36 engage the bar 20 at opposite sides thereof, to prevent the bracket 32 and, consequently, the pad 30 from being rotated around the frame 10 and from being accidentally lifted therefrom. The two lips 35 and 36 also serve to position the pad 30 in a fixed position substantially out of contact with the resilient supports 14, so that the pads do not rest on these resilient supports and do not hamper their movements.
Each bracket 32 is secured to the resilient body 31 by one or more headed fastening elements such as rivets 37 having shanks 38 with enlarged heads 39 at one end, engaging the body 31. The shanks 38 extend through holes 40 in the rounded portion 34 of the bracket and the other ends of the rivets are upset against the underside of the rounded portion 34.
Thus, the present invention provides a trampoline in which the resilient supports stretched between the frame and the trampoline bed can individually slide along the frame, in response to the forces acting upon the bed, and adjust themselves to a position which is always perpendicular to the edge of the bed, so that the rebound of the acrobat is straighter and more regular. The same rods used to slidably mount the resilient supports are also used to anchor the protective pads in a predetermined position from which they cannot be accidentally lifted. However, the pads can easily be removed by grasping the ouside edge of the pad to lift it while simultaneously pressing down on the upper surface of the pad to slide the brackets 32 out of engagement with rods 20. For mounting the pads the procedure is reversed.
The manufacture of the various parts of the trampoline is particularly simple and economical. First, the fabric sheet of the trampoline bed can be produced according to any conventional textile process, such as weaving, while the anchor rods 18 and 23 can be slipped into doubled back strips of fabric 15 and sewn to the fabric by means of stitches 42 parallel to the edge 16 of the bed 13.
While the invention has been described by means of a preferred embodiment thereof, it is to be understood that various modifications and alternative constructions can be made by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Heretofore, commonly known trampolines have been constructed by tightly stretching a trampoline bed formed of flexible fabric by means of numerous resilient supports, such as coil springs, within a frame formed of rigid material. Usually, these springs are secured, at one of their ends, to loops or holes provided on the frame, and at the other end to anchors attached to the trampoline bed, so that the position of the springs is exactly determined and cannot be individually altered.
In the use of trampolines constructed in this manner, the acrobat often descends on the bed at a location away from the center of the frame toward one end or one side thereof so that his rebound is no longer vertical, and he may even be thrown off of the trampoline by this irregular rebounding action. It has been discovered that this effect is caused by the springs being pulled sideways upon the exertion of a sideways force on portions of the bed by the downward movement of an acrobat thereon, so that the force of the springs does not act perpendicularly upon the edge of the bed and, consequently, produces an irregular rebounding action thereof.
It is, therefore, a main object of this invention to provide a trampoline which always produces a vertical rebound independently from the location at which the acrobat descends on the trampoline bed.
Another object of the invention is to provide a trampoline having a frame and a trampoline bed stretched within the frame by means of a plurality of coil springs, in which the frame and the springs are covered by a protective pad which can easily be removed from the trampoline but which cannot accidentally fall off the same.
Still another object of the invention is to provide a trampoline in which the trampoline bed is formed of conventional fabric sheet which is free of sharp-edged corners.
Other objects and advantages will become apparent from the following detailed description of the invention, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a fragmentary partially broken away plan view of an improved trampoline according to the invention;
FIG. 2 is an enlarged detail plan view of a corner portion of the trampoline bed of FIG. 1;
FIG. 3 is an enlarged fragmentary partially broken away plan view of a side portion of the improved trampoline, showing a variant with respect to FIG. 1;
FIG. 4 is a further enlarged sectional view taken along the line 4--4 in FIG. 3 and showing a pad positioned over the springs secured to the frame means;
FIG. 5 is a further enlarged sectional view taken along the line 5--5 in FIG. 3 and showing the pad mounted on the frame of the trampoline; and
FIG. 6 is a perspective detail view of a bracket used to mount the protective pad on the frame of the improved trampoline.
Referring now more particularly to the drawings, an improved trampoline according to the invention comprises a frame 10 which can have any desired polygonal or even circular shape. According to a preferred embodiment of the invention, however, the frame 10 is of generally rectangular shape and comprises a plurality of straight portions 11 angularly related to each other. Preferably, the frame 10 is formed of a rigid continuous tubular structure, with rounded corner portions 12, but the invention is not limited to this particular feature, since any conventional frame can be used, such as for example a multi-sectional foldable frame.
A trampoline bed 13 having a smaller surface than the area defined by the frame 10 is positioned within the frame and connected to the same by means of a plurality of resilient supports 14, for example coil springs, rubber cables or the like. The bed 13 can be formed of any conventional sheet, but preferably it comprises a flexible fabric sheet having substantially the same proportions as the frame 10 which surrounds the bed in spaced relationship thereto. According to a particularly advantageous feature of the invention, a plurality of fabric strips 15 are doubled over and attached along the edge 16 of the trampoline bed 13, for example by sewing, thus defining a plurality of equidistantly spaced loops 17, as shown in more detail in FIG. 4. A plurality of anchor rods 18, each fashioned integrally from suitable bar stock and having a saddle or loop 19 formed midway therein, have their straight ends inserted into the loops 17 of two adjacent strips 15, thus providing means for fixedly connecting a first end of each of the resilient supports 14 to the edge 16 of bed 13 at predetermined intervals.
One advantage of this arrangement consists in that the strips 15 can be attached to any kind of fabric sheet which need not be formed itself of interwoven spaced strips. Further, the anchor rods 18 provide a firm anchorage for the resilient supports 14 while, at the same time, they do not restrict the flexibility of the edge 16 of the trampoline bed 13.
According to the invention, the frame 10 of the trampoline is provided with means for individually slidably connecting the second end of each of the resilient supports 14 to the frame to permit this second end to slide parallel to the frame 10 upon the exertion of a sideways force on portions of the bed by the downward movement of an acrobat thereon. Consequently, the resilient supports 14 are always individually perpendicular to the edge 16 of the trampoline bed 13 and the rebounding action of the bed is always substantially vertical.
One embodiment of this feature comprises a rod, or bar 20, arranged parallel to the edge 16 of the trampoline bed 13 and fixedly secured to the frame 10 in spaced relationship thereto. Preferably, however, a plurality of rods 20 are secured to the inside of the straight portions 11 of the frame 10 in spaced relationship thereto, for example by means of saddle 21 formed in the rods 20 and welded to the frame 10. These saddles 21 can be provided at any desired intervals along each rod 20, the only condition being that the distance between two adjacent saddles should be large enough to permit unrestricted sliding movement of the hooked portion 22 of the second end of the resilient supports 14. FIG. 1 shows an embodiment in which the distance between two adjacent saddles 21 is designed to receive only one hook 22, whereas FIG. 3 shows an embodiment in which the distance is sufficient to permit the sliding movement of three hooks 22 between two adjacent saddles 21. Each of the hooks 22 has a diameter larger than the diameter of rod 20, so that the hooks have substantially only a point contact therewith in order to reduce friction to a minimum.
Referring particularly to FIGS. 1 and 2, the corner portions of the trampoline bed 13 are provided, according to the invention, with respective anchor rod elements 23 attached thereto and free of sharp edges. Each such anchor rod element 23 comprises two rod portions 24 and 25 angularly related to each other and joined by a rounded vertex portion 26, and each of said rod portions 24 and 25 has a medial saddle or loop 27 and 28, respectively, similar to the loops 19, to be connected with the resilient supports 14 positioned at the corners 12 of the frame. These anchor rod elements have the double purpose of serving as reinforcement for the corner portions of the bed, thus preventing tearing in a diagonal direction, and of providing bed corners which are free of sharp-edged projections, so that an acrobat using the trampoline is not likely to become injured thereby. In addition, the rounded corners of the frame 12, the resilient supports 14 adjacent thereto, and the corners of the bed define respective opening 29 which can be used by children to climb on and off the trampoline bed 13, and the lack of sharp-edged parts prevents the clothes of the children from being torn.
According to a further feature of the invention the improved trampoline is provided with at least one resilient pad 30 mounted on frame 10 for covering the upper surface of the frame 10 and the resilient supports 14. Preferably, each straight section 11 of the frame is provided with such a resilient pad 30 which is generally coextensive in length thereto, in order not to cover the access openings 29. In general, each protective pad 30 comprises an elongated and preferably generally rectangular shaped body 31 having flat exterior surfaces, and the resilient material utilized is preferably sponge rubber or polyethylene foam. It has also been found desirable to cover the exterior of the body with a sheet 33 of weather resistant fabric such as knit cotton sheet covered with a vinyl plastic.
One or more mounting brackets 32 are secured to the body and adapted to releasably connect the pad 30 to the frame structure 10 at points spaced from each other along the length of the frame structure in a manner to prevent the accidental lifting of the pad 30 from the frame structure 10 and to position the pad in substantially horizontal position and in spaced relationship to the resilient supports 14 to permit a free sliding movement thereof.
Each mounting bracket 32, shown in detail in FIG. 6, is formed from a flat strip of rigid metal, bent to form a rounded, substantially semicircular portion 34 integral with a flat lower lip 35 extending outwardly in a substantially radial direction with respect to the portion 34. A flat upper lip 36 is partially punched out from the rounded portion 34 and extends outwardly from said portion in parallel spaced relationship to the lower lip 35. The diameter of the rounded portion 34 corresponds to the diameter of the tubular frame 10, and the space between the lips 35 and 36 is substantially the same as the diameter of rod or bar 20. In the operative position of the bracket, as shown in FIG. 5, the rounded portion 34 partially surrounds the tubular frame 10, and the lips 35 and 36 engage the bar 20 at opposite sides thereof, to prevent the bracket 32 and, consequently, the pad 30 from being rotated around the frame 10 and from being accidentally lifted therefrom. The two lips 35 and 36 also serve to position the pad 30 in a fixed position substantially out of contact with the resilient supports 14, so that the pads do not rest on these resilient supports and do not hamper their movements.
Each bracket 32 is secured to the resilient body 31 by one or more headed fastening elements such as rivets 37 having shanks 38 with enlarged heads 39 at one end, engaging the body 31. The shanks 38 extend through holes 40 in the rounded portion 34 of the bracket and the other ends of the rivets are upset against the underside of the rounded portion 34.
Thus, the present invention provides a trampoline in which the resilient supports stretched between the frame and the trampoline bed can individually slide along the frame, in response to the forces acting upon the bed, and adjust themselves to a position which is always perpendicular to the edge of the bed, so that the rebound of the acrobat is straighter and more regular. The same rods used to slidably mount the resilient supports are also used to anchor the protective pads in a predetermined position from which they cannot be accidentally lifted. However, the pads can easily be removed by grasping the ouside edge of the pad to lift it while simultaneously pressing down on the upper surface of the pad to slide the brackets 32 out of engagement with rods 20. For mounting the pads the procedure is reversed.
The manufacture of the various parts of the trampoline is particularly simple and economical. First, the fabric sheet of the trampoline bed can be produced according to any conventional textile process, such as weaving, while the anchor rods 18 and 23 can be slipped into doubled back strips of fabric 15 and sewn to the fabric by means of stitches 42 parallel to the edge 16 of the bed 13.
While the invention has been described by means of a preferred embodiment thereof, it is to be understood that various modifications and alternative constructions can be made by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.