CO wrote:
If you are looking at a swivel umbrella bracket, Kupo is the strongest. The Kupo brackets have a large clamping area and will not slip from the leverage the umbrella exerts on it. I use one with my 41" umbrellas. I had a Manfrotto swivel umbrella bracket once. The leverage from my 41" umbrellas would cause it to slip even when well tightened.
You can use a bracket like CO mentions or you can use a simple cold shoe adapter.
Below is an Ebay listing for such a device. This is NOT a vendor recommendation.