Benjamin Franklin Medal Token

I discovered two medallions/shields of two American Presidents in an old farm shed in the RSA’s northern province some 40 years ago. They have traveled with me in and out of trash bins ever sins. I have over years been trying to find out how they got to Africa, with no results. Even art collectors here and even the US couldn’t help. I by chance game across your website and wonder if you could maybe help. They are made of tin/bronze coated ?? and are about 60 cm across. The artist imprint is something like A Acnens. Could you please assist by giving me some background on these items ?? Please. Regards Jan. Can you help Jan identify this item? If so, please click on the comment button and share your thoughts. Thank you.