Pocket volt meter (German) circ 1930
This is a German pocket (fob watch style) D.C. volt meter, sold to and used by radio users who wanted to know the condition of their H.T. and L.T. batteries for their early valve radios. The meter, housed in a Bakelite case has two scales, one being 0-240 volt and the other 0-6 volt with a negative mark on the case above the contact pin. This has a manufacturer’s logo mark of a letter K in a circle of which research continues to trace the manufacturer and the D.R.G.M. stamping on the lead contact pins confirming its German heritage. This example is in good, fully working condition.
D.R.G.M.
There was already a law on design protection in Germany from 1876, but as a result of increasing industrialization and the increased movement of goods, especially in the wake of growing economic interest perception on a national level, it was decreed that a new utility model was created.
A Reichsgesetz of 1 June 1891 created the legal requirements for Germany, so that the Imperial Patent Office introduced the "German Reichs-Gebrauchsmuster" on 1 October 1891. Zahlreiche Produkte wurden so zwischen 1891 und etwa 1945 mit der Kennzeichnung „DRGM“ versehen, oft unter Hinzufügung der Musternummer, die es heute erlaubt, die Entstehungszeit mancher materiell überlieferter historischer Geräte auf ein bestimmtes Jahrzehnt einzugrenzen. [1] Auch einige Jahre nach dem Zweiten Weltkrieg war diese Kennzeichnung in Westdeutschland gelegentlich noch üblich, die Abkürzung lautete dann entsprechend "DBGM" (Deutsches Bundes-Gebrauchsmuster). Many products being made between 1891 and about 1945 bears the marking "DRGM", often with the addition of the pattern number that allows today to narrow down the time of origin of some material of traditional historical units to a particular decade. Some years after the Second World War II, this marking was still customary in West Germany with the abbreviation then corresponding to "DBGM" (German Federal Utility Model).