I rate METAL DETECTORS! Research here before you buy!
Metal Detecting Vacation
It looks to me like it might have been part of an old toy. Those designs look like they were supposed to represent mechanical components of something (maybe an old toy car? or a rack on the back of something with a wheel?)
I agree with Brent. If I rotate the image 90° counterclockwise I see the rear wheel of a motorcycle and one cylinder of a V-twin engine.