I think you are right on the name Imhoff and Lange.
Here's another quote from a site that won't pull up a pic.
121201T1 Hand vise DTM
Drop forged malleable iron, 3 1/2" long, 1 1/4" wide jaw, signed "IMHOFF & LANGE".
DATM (1999, 1030) indicates Imhoff & Lange is a foreign company that made bits. This maker's mark has never been seen
before by the Liberty Tool Co.
and more from the same site, appears to be a German company.
112303T1 Screw box and screw tap DTM
Wood and steel, 3/4", signed "Imhoff & Lange" "Germany" "8" and "7/8".
The screw box is accompanied by a 3/4" screw tap marked "3/4", "19" and "West Germany". It was received in November,
2003, from an anonymous donor. It is an excellent modern example of an age old woodworker's tool. The purpose of this
tool is to cut threads onto 7/8" dowels to be used as handles, etc. to be screwed into holes that have been threaded with a
tap made to cut threads in a wooden hole. For example, it could be used for making wooden clamps with wooden screws.
122303T1 Screw box and screw tap DTM
Wood screw box and cast steel tap, 9 1/2" long, 2 1/16" wide, 1 3/4" deep box, 5 7/16" long, 7/8" wide tap, signed
"IMHOFF &LANGE GERMANY" and "1" and "7/8" on box; "7/8" and "1" on tap.