US6840893B2 - Jumping device for exercise - Google Patents

https://www.google.de/patents/US6840893?dq=ininventor:%22Tae-Hyuk+Yoon%22&hl=en&sa=X&ei=cNN4U-6WCsbB7Ab4CA&ved=0CDoQ6AEwAA

Disclosed is a jumping device for exercise including an arc-shaped plate spring, a vertical member coupled to the plate spring, a footrest coupled to the vertical member while extending horizontally, a hinge lever hingably coupled to the footrest, a…