It´s good to see this head come back to life.
I am, too thinking the head was upside down, the handle clearly wasn´t teh first one on it and sat in teh head neither straight nor really fitting.
My brother mentioned that this Axe might be a German army (Bundeswehr) Axe like it was carried on Motor vehicles or one from the ex-GDR "Volksarmee", seems both carried Axes like that on their vehicles.
I just googled Helko Axes and they seem to be still producing Axes in Wuppertal, Germany (A city less known than Solingen, but nearby and producing very good cutlery and steel products for th least few hundred years)
Their American site is here:http://www.helkonorthamerica.com/
As they are a Western German manufacturer, i guess we can rule them ouut for equipping the ormer GDR, making your Axe most likely a Bundeswehr item.
I found them for sale at a german Surplus-shop.
Here you can get an idea of the original handle shape:http://www.raeer.com/shopexd.asp?id=20141