Heavy Tools actually came from Austria more precise Mattighofen/Salzburg, they made quite nice Mountain Bikes (hardtails and fullys), BMX (mainly re-branded KHE) and in the mid 90´s Trial MTB, they also sold snowboards and nice mountain bike clothing (the relaxed type we see now days but this where the 90´s) .
The company where owned by some brothers (really nice guys) but the lost there money late 90´s( to many customers who forgot to pay there bills) after that one of the brothers started up again with the brand HiTech and the name Heavy Tools ended up with the German importer (that's why some think it where a German brand)
I still have two proto types of the last fully where you could change the amount of travel in the rear, a Titanium hardtail (Sandvik frame), I also have some new RIF/Raf Team clothing and some new mechanic's wear (the type you take over your head and tie around the waist) I have the parts from my time working with them and riding for them.
When I´m home in my other house where the frames and other bike parts are I will take some pictures so you can see what they also made
The model you have is the model lower then the Equipe series, still a great frame but the parts a little cheaper then on the Equipe´s (they focused on the frame on all there models so no crappy frames).
The bike you have are looking great and it will look like that for years if you want, you don´t see them on every corner so one off the kind
I don't know if you have seen this catalog http://www.mtb-kataloge.de/Bikekataloge ... s/1994.pdf
You can see your bike in that and also take a look at the HT Pro, my personal favorite of the hardtails, great handling, great frame and deep racing green with a little gold flakes flashing in the sun, if I could get one in mint condition again I would buy it at once.
You have to use your imagination when you read my post, I´m not english but understands all you write so ask for your patience you might even get a laugh over it