OK, I've found the book, and there were 4 trip arm types. This is out of a 1931 German catalogue. The Type 22 is referred to here as a P22; the P22v (vertical spring) P22h (horizontal spring). And it appears the trip arms were also compatible with the Type 32 and Type 33 as well. I know I have a Type 22 (somewhere) that originally came off a Lister, and that has vertical springs, but the trip arm is horizontal. I think the trip arm in this case, was made by Lister, and not Bosch. I maybe wrong, but I don't have any earlier references to go to.