Making an escapement wheel for verge escapement (clock)

To understand my question, please take a look at:

https://www.youtube.com/watch?v=BoeP0adbDKg 

My basic "challenge" was to make a 3D modell of a "crown wheel". After some research I downloaded and installed DesignSpark, which I found really simple comparing with f.e. AutoCAD.

I'm really a beginner in DesignSpark. I can make a "normal" gear (=wheel) for a clock. But these kind of wheels with vertical teeth makes me puzzled. I'm trying polygons, curves pulled and then rotated as patterns. So I'm getting teeth, but they are not on a cylindric face. I'm really far away...

Did anybody made such kinf of a wheel?

Thanks a lot for any solution!