I always had trouble with bulldog clips and in cases pause, home all, or printing anything over 160 x 160 mm Fan unit kicks the clips and have bed leveling problem immediately.

I searched and checked many clips for heat bed but all have the same problem or brings new one. 

I found Jolly_Oli's Ormerod Heatbed clip but still it was big and useless for Wanhao i3. I inspired and redesigned it for Wanhao i3 with shorter footage on the glass. My glass bed has 0.5 mm silicone under it and I removed the Wanhao plastic print surface.