| 摘要 |
A mobile base device for a sun umbrella including a base cover. A bearing support is arranged inside the base cover and is hinged with a main lifting arm via a stiffened plate mounted thereon. An outer end of the main lifting arm is screwed to a lifting screw mounted on the bearing support via a lifting screw sleeve and an inner end of the main lifting arm is fixedly coupled to a set of secondary lifting arms through joints. A central portion of the set of secondary lifting arms is hinged with a set of stiffened plates mounted on the bearing support and a lower portion of the outer end of the set of secondary lifting arms is fixedly coupled to a set of casters. The lifting arms are hinged to the umbrella base via the bearing support and the lifting arms are enabled to move upwards or downwards by means of controlling the end of the main lifting arm by a handle and meanwhile allow the secondary lifting arms to drive the casters mounted thereon to drop or lift. Thus, the sun umbrella moves easily and rapidly when the casters touch the ground and the umbrella will be securely fixed when the casters lift and foot mats touch the ground. Such structure has the advantages of easy movement and fixation as well as practicality and convenience.
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