Abstract:
A wheel assembly for attachment to the leg of a trampoline has means for moving the wheel from a first raised position where the wheel is not supporting the trampoline leg above the ground, to a second position where the wheel is supporting the trampoline leg above the ground. In that way the trampoline can be rolled on wheels without having to subsequently remove the wheel assemblies for storage.

Description:
TECHNICAL FIELD 
     The invention relates to wheel assemblies for moving trampolines. 
     BACKGROUND 
     Many homes have a trampoline set up for use by family members, typically on a backyard lawn surface. Such trampolines are typically supported on opposed U-shaped legs, but the size, shape and number of legs is highly variable depending on the manufacturer, size and shape of the trampoline. To avoid having the grass under the trampoline die, and to permit the grass to be cut, it is necessary to periodically move a trampoline which is set up on a user&#39;s lawn. This is usually done by lifting or dragging the trampoline, which is difficult for a person to do alone. 
     It is known to attach wheel assemblies to trampolines to facilitate moving them. It is known to provide a pair of wheel assemblies, each having two or three wheels. The wheel assemblies are designed for indoor use, such as in gymnasia. Such wheel assemblies are designed to fit into receptacles provided in the trampoline frame when the trampoline is moved, and are removed when the trampoline is ready to be used. Examples are shown in U.S. Pat. Nos. 3,116,809 and 3,156,318. Such assemblies are difficult to store when the trampoline is in use, and not all trampoline designs may be suited or adapted to have one of these assemblies attached to it. 
     There is therefore a need for a wheel assembly which can be used on any design of trampoline and which can remain attached to the trampoline during use. 
     The foregoing examples of the related art and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings. 
     SUMMARY 
     The following embodiments and aspects thereof are described and illustrated in conjunction with apparatus which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above-described problems have been reduced or eliminated, while other embodiments are directed to other improvements. 
     The invention therefore provides a wheel assembly for attachment to a trampoline leg to enable a trampoline to be rolled on a surface, comprising: i) an attachment element having means for securing the wheel assembly to a trampoline leg; ii) an elongated element mounted on the attachment element and movable in a direction having a component perpendicular to the surface; iii) an axle-mounted wheel pivotally connected to the elongated element; and iv) means for reversibly moving the elongated element from a first position in which the wheel is raised relative to the attachment element to a second position in which said wheel is lowered relative to the attachment element. 
     In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following detailed descriptions. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive. 
         FIG. 1  is a front perspective view of a first embodiment of the invention. 
         FIG. 2  is a rear perspective view of the embodiment shown in  FIG. 1 . 
         FIG. 3  is a perspective view of the embodiment shown in  FIG. 1  attached to a trampoline leg in the wheel up position. 
         FIG. 4  is a perspective view of the embodiment shown in  FIG. 1  attached to a trampoline leg in the wheel down position. 
         FIG. 5  is a cross-section perspective view taken along line B-B of  FIG. 1 . 
         FIG. 6  is a top cross-section view taken along line B-B of  FIG. 1 . 
         FIG. 7  is a front elevation view of a second embodiment of the invention. 
         FIG. 8  is a rear elevation view of the embodiment shown in  FIG. 7  in the wheel down position. 
         FIG. 9  is a cross-section view taken along line A-A of  FIG. 8 . 
         FIG. 10  is a top view of the embodiment shown in  FIG. 8  in the wheel down position. 
         FIG. 11  is a perspective view of a third embodiment of the invention. 
         FIG. 12  is a front elevation view of the embodiment shown in  FIG. 11  in the wheel up position. 
         FIG. 13  is a rear elevation view of the embodiment shown in  FIG. 11  in the wheel down position. 
         FIG. 14  is a detail rear perspective view of the embodiment shown in  FIG. 11  in the wheel up position. 
         FIG. 15  is a perspective view of a fourth embodiment of the invention shown in the wheel up position. 
         FIG. 16  is a perspective view of the embodiment of the invention shown in  FIG. 15  in the wheel down position. 
         FIGS. 17A ,  17 B are schematic views in cross-section of the embodiment shown in  FIG. 15  illustrating the operation of the locking pin. 
     
    
    
     DESCRIPTION 
     Throughout the following description specific details are set forth in order to provide a more thorough understanding to persons skilled in the art. However, well known elements may not have been shown or described in detail to avoid unnecessarily obscuring the disclosure. Accordingly, the description and drawings are to be regarded in an illustrative, rather than a restrictive, sense. 
     With reference to  FIG. 1 , a first embodiment of the pivoting wheel assembly is designated by numeral  10 . It comprises a leg  22 , which may be a hollow tube for lightness, for example manufactured from aluminum. Wheel  12  is mounted on axle  14  which is carried on caster  6  which is rotatably secured on the lower end of leg  22 . The upper end of leg  22  is fastened, for example by welding, to rotating ring  21  which is mounted for rotation on cylindrical hub  19 . Hub  19  is fixed to base plate  11 . Rotating ring  21  is fastened, for example by welding, to ring plate  23  which is retained on hub  19  by retaining ring  5  and washer  3 . Ring plate  23  has two holes  17  which are sized to receive retractable pin  16 . Pin  16  slides in holes  18  of pin bracket  13  and plate  11 . Pin  16  is biased into holes  17  by a spring  15  and has secured to its outer end a pin ring  4  to permit the user to withdraw the end of pin  16  from hole  17 . 
     Base plate  11  has holes  20  through which are removably secured U-shaped clamps  25  which have threaded ends for securing in holes  20  using threaded nuts. To use the device, as shown in  FIG. 3 , with the leg in the wheel up position shown, the base plate  11  is secured to trampoline leg  30  at the appropriate height by clamps  25 . When it is desired to move the trampoline, the user pulls pin  16  out of hole  17  using pin ring  4 , which permits rotating ring  21  and leg  22  to rotate. By raising the trampoline leg slightly, leg  22  is rotated 180 degrees so that pin  16  snaps into the second hole  17  and the trampoline leg  30  is then supported on wheel  12  above the ground, as shown in  FIG. 4 . Preferably a minimum of two or three wheel assemblies  10 , and most preferably four wheel assemblies  10  are thus attached to the trampoline legs at spaced locations and when all the wheels are in the down position the trampoline can be readily rolled to a new location. When it is desired to set the trampoline down for use at a location, the process is reversed by the user pulling pin ring  4  to allow the leg  22  to rotate back to the wheel up position. The wheel assemblies  10  can remain on the trampoline legs in the wheel up position without disturbing the use of the trampoline. 
     A second embodiment of the pivoting wheel assembly is designated by numeral  70  in  FIGS. 7 through 10 . Wheel and pivoting caster assembly  82  is mounted on the end of lever  75  which has grip  74 . Lever  75  is fastened, for example by welding, to bushing  80  which rotates on axle  81 ,  83 ,  85  which is fixed to base plate  78 . Bushing  80  is welded to locking ring  84  which has holes  72  for receiving a locking pin  73 . Pin  73  is biased into holes  72  by a spring (not shown) and has a handle end  76  which slides in housing  86 . Base plate  78  has holes for removably receiving U-shaped clamps  77 ,  79 . 
     To use this embodiment, as in the first embodiment, with the lever  75  in the wheel up position shown in  FIG. 7 , the base plate  78  is secured to trampoline leg  30  at the appropriate height by clamps  77 ,  79 . When it is desired to move the trampoline, the user pulls pin  73  out of hole  72  using handle  76 , which permits rotating ring  84  and lever  75  to rotate. By raising the trampoline leg slightly, lever  75  is rotated  90  degrees to the position shown in  FIG. 8  so that pin  73  snaps into a second hole  72  and the trampoline leg  30  is then supported on wheel  82  above the ground. Preferably four wheel assemblies  70  are thus attached to the trampoline legs at four locations and when all the wheels are in the down position the trampoline can be readily rolled to a new location. When it is desired to set the trampoline down for use at a location, the process is reversed by the user pulling out pin  73  and rotating lever  75  back ninety degrees to the wheel up position. The wheel assemblies  70  can remain on the trampoline legs in the wheel up position. 
     A third embodiment of the pivoting wheel assembly is designated by numeral  110  in  FIG. 11 . Wheel and pivoting caster assembly  122  is mounted on the end of telescoping tube  111 . Tube  111  telescopes inside outer tube  113  which is secured to clamping plate  116  by bolts  121 ,  125  or the like. Bracket  112  is fastened, for example by welding, to tube  113 . Lever handle  114  rotates on pin  118  which is fixed in bracket  112  and second pin  118  which connects lever handle  114  to lever driver  115 . The lower end of lever driver  115  rotates on pin  119  in tube  111 . Clamping plate  116  has holes for removably receiving U-shaped clamps  131 ,  132  ( FIG. 14 ). To accommodate trampoline legs of differing angle, bolt  125  slides in slot  127  in clamping plate  116 . 
     To use this embodiment, as in the first embodiment, with the lever handle  114  in the wheel up position shown in  FIG. 12 , the clamping plate  116  is secured to trampoline leg  30  at the appropriate height by clamps  131 ,  132 . When it is desired to move the trampoline, the user lowers handle  114  to the position shown in  FIG. 13 , which lowers wheel and caster  122  into contact with the ground and raises the trampoline leg above the ground. Preferably four wheel assemblies  110  are thus attached to the trampoline legs at four locations and when all the wheels are in the down position the trampoline can be readily rolled to a new location. Padlock hole  130  is provided to permit the assembly to be locked in the wheel up position so that children cannot easily move the trampoline. When it is desired to set the trampoline down for use at a location, the process is reversed by the user rotating handle  114  back ninety degrees to the wheel up position. The wheel assemblies  110  can remain on the trampoline legs in the wheel up position. 
     As will be apparent from  FIG. 11-14 , the relative location of the axes created by pins  118  to lever driver  115  and pin  119  causes lever handle  114  to reach an over-center point of rotation when rotated to the position shown in  FIG. 13  which retains lever handle  114  securely in that position until a rotational force is applied to overcome the resistance created by the over-center relationship and thereby continue rotation of lever handle  114  to the position shown in  FIG. 11 . Similarly the relative location of the axes created by pins  118  to lever driver  115  and pin  119 , and the indentation  123  in the edges of lever driver  115 , causes lever handle  114  to reach an over-center point of rotation when rotated to the position shown in  FIG. 12  which retains lever handle  114  securely in that position until a rotational force is applied to overcome the resistance created by the over-center relationship and thereby continue rotation of lever handle  114  to the position shown in  FIG. 11 . In addition, one or more dimples may be formed on the inner surface of handle  114  between the two pins  118 , and possibly also corresponding indentations on the outer surface of lever driver  115 , to cause a frictional engagement when handle  114  is in the position shown in  FIG. 12  in order to further retain lever handle  114  securely in that position until force is applied to rotate it. 
     A fourth embodiment of the pivoting wheel assembly is designated by numeral  150  in  FIG. 15 . Wheel and pivoting caster assembly  152  is mounted on the end of telescoping inner tube  151 . Tube  151  telescopes inside outer tube  153  and has a locking pin  154  and handle  157  secured thereto and extending therefrom. Outer tube  153  has a pin-engaging slot  155  and is secured to mounting plate  156  by welding or the like. Mounting plate  156  has holes for removably receiving U-shaped clamps  160 ,  162  which have threaded ends which extend through holes in saddle-shaped brackets  164 ,  166  and are secured using threaded nuts. 
     To use the device, as shown in  FIG. 15 , the leg is in the wheel up position shown in  FIG. 15  and  FIG. 17B , with the locking pin  154  locked in the upper notch  168  of slot  155  due to the weight of the inner tube. The mounting plate  156  is secured to trampoline leg  30  at the appropriate height by tightening clamps  160 ,  162  and brackets  164 ,  166  against leg  30 . When it is desired to move the trampoline, the user lifts trampoline leg  30  and raises locking pin  154  out of notch  168  using handle  157  to lift inner tube  151 , and rotates inner tube  151  counterclockwise, which permits locking pin  154  to enter the vertical length of slot  155 . The weight of inner tube  151  and wheel  152  then causes inner tube  151  to telescope downwardly relative to outer tube  153  until locking pin  154  reaches the bottom  170  of slot  155 . The trampoline leg  30  is then lowered and supported on wheel  12  above the ground, as shown in  FIG. 16  and  FIG. 17A  with locking pin  154  held in notch  172  by the weight of the trampoline. Preferably a minimum of two or three wheel assemblies  150 , and most preferably four wheel assemblies  150  are thus attached to the trampoline legs at spaced locations and when all the wheels are in the down position the trampoline can be readily rolled to a new location. When it is desired to set the trampoline down for use at a location, the process is reversed by lifting the trampoline, thereby returning locking pin  154  to position  170 . The user then lifts handle  157  to raise the inner tube  151  in slot  155 , and then rotate the locking pin  154  to rest in notch  168 . The wheel assemblies  150  can then remain on the trampoline legs in the wheel up position without disturbing the use of the trampoline. 
     While it is preferred that the wheel assembles according to the invention can be quickly secured to and removed from the trampoline legs such as by using threaded clamps and bolts, the invention can also function wherein the wheel assembly is more permanently secured to the trampoline leg, such as by screwing into the trampoline or welding to the leg. 
     While a number of exemplary aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope.