50 is of a diameter similar to, and slightly smaller than, the diameter of the pole 102 of the umbrella 100. Further friction between the collar member 50 and the pole 102 of the umbrella 100 may be achieved by positioning a rubber insert between the collar member 50 and the pole 102 of the umbrella 100.

As briefly discussed above, the retention assembly 16 further includes a plurality of nylon straps 56 extending from the outer surface 54 of the collar member 50. Each of the plurality of straps 56 includes a first end 58 secured to the collar member 50 and a second end 59 adapted for attachment to, and adjustment relative to, the anchoring members 20a-20e. The first ends 58 of each of the plurality of straps 56 are secured to D-rings 72 extending from the outer surface 54 of the collar member 50. Each of the straps 56 includes a mechanism that allows the effective length of the strap 56 to be selectively shortened to pull the collar member 50 down toward the platform assembly 14 and hold the base 104 of the umbrella 100 securely in place. The mechanism shown in the disclosed embodiment is generically a length adjustment buckle 78 of any of a variety of commonly available constructions. For example, it could be a ratcheting buckle or a spring-loaded buckle commonly used with lashing straps. In accordance with other embodiments, the straps could be replaced with conventional bungee cords. The straps could also constructed from a single strap member with a first end having a spring-biased buckle and a free second end shaped and dimensioned to pass through the buckle, wherein the free second end of the strap member is passed about the anchoring member, through the D-ring, and is then passed through and locked relative to the buckle to adjust the length of the strap extending between the collar member and the anchoring member. While spring-biased buckles are disclosed above, it is appreciated various buckle arrangements could be used in accordance with the present invention.

In accordance with another embodiment as shown with reference to FIGS. 13 to 16 a dolly 210 with a more modular construction is disclosed. As with the embodiment disclosed above, the umbrella dolly 210 is designed for a cantilever umbrella 100 and its weighted base, which are to be assembled on top of the umbrella dolly 210 itself. The umbrella dolly 210 of the disclosed embodiment is approximately 36 inches across and is built to support many hundreds of pounds and dynamic wind pressure.

As with the prior embodiment, the umbrella dolly 210 includes a platform assembly 214 upon which the umbrella 100 sits when fully assembled and in use. The umbrella dolly 210 also includes a retention assembly 216 constructed to extend between the platform assembly 214 and the umbrella 100 in a manner providing additional support and ensuring that the umbrella 100 and the platform assembly 214 are securely connected to enhance the stability of the umbrella 100 as it sits upon the umbrella dolly 210.

The platform assembly 214 includes a central support platform 218. The central support platform 218 comprises a plurality of a platform members 222a-222e held together by a plurality of anchoring members 220a-220e members extending between adjacent platform members 222a-222e. The disclosed embodiment is modular in constructions allowing for the platform assembly to be conveniently assembled and disassembled as desired, allowing for ease of shipping and transport from place to place.

Each of the platform members 222a-222e includes an upper surface 226, a lower surface 228, and a sidewall 230 extending between the upper surface 226 and the lower surface 228. Each of the platform members 222a-222e also includes a wide first end 232 and a narrow second end 234 with lateral edge members 236a, 236b extending between the wide first end 232 and the narrow second end 234. The wide first end 232 is constructed with a convex outer edge 232e, while the narrow second end 234 is constructed with a concave outer edge 234e. Each of the platform members 222a-222e is also provided with a first caster wheel 246a secured to the lower surface 228 thereof adjacent to the wide first end 232 thereof and a second caster wheel 246b secured to the lower surface 228 thereof adjacent the narrow second end 234 thereof. Four bolts are used to secure each caster wheel 246a, 246b to each platform member 222a-222e. The caster wheels 246a, 246b are preferably lockable caster wheels to provide a user with the option of conveniently locking the dolly 210 in position. The positioning of the lockable swivel caster wheels 246a, 246b as disclosed provides for ease of rolling. The lockable swivel caster wheels 246a, 246b are off-the-shelf items and various types of caster wheels may be used without departing from the spirit of the present invention.

The plurality of platform members 222a-222e are held together by the anchor members 220a-220e that extend between adjacent platform members 222a-222e. In particular, the anchor members 220a-220e secure adjacent platform members 222a-222e together by extending between the lateral edge members 236a, 236b adjacent the wide first ends 232 thereof. It is appreciated the anchor members 220a-220e may be selectively secured in apertures 223 of the platform members 222a-222e using various mechanisms; for example, the ends of the anchor members may be provided with threaded connectors that engage mating threads along the platform member, the platform members may be provided with releasable friction members (for example, clips) that engage the anchor members as they are inserted into the platform member, set screws may be passed through the platform members to engage the anchor members in a manner securing the anchor members relative to the platform members, etc.

In addition, and considering the alternate embodiments disclosed with reference to FIGS. 13 to 16 and FIG. 17, the anchor members 220a-e may be provided with a square or rectangular cross section profiled as shown with reference to the embodiment of FIGS. 13 to 16 or the anchor members 220a-e may be provided with a circular cross section profile as shown with reference to the embodiment of FIG. 17. Where the anchor members 220a-e are provided with a circular cross section profile as shown with reference to the embodiment of FIG. 17 it is contemplated a threaded connection could be used. Where the anchor members 220a-e are provided with a square or rectangular cross section profile as shown with reference to the embodiment of