Sun Umbrella Centralizer

This is one of my first own designs I made in tinkercad.
Problem:
We bought a new umbrella and unfortunately it has had a smaller diameter than the old one and didn't fit exactly in the umbrella stand.

Solution:
We need an adapter or centralizer to re-use the existing umbrella stand.

Updates:
v1: Initial version as shown on the picture
v2: smoothened the circles