PIEPER Paul

Paul PIEPER was born on 12 January 1880 in Moyland (Rheinland).
In 1923, at the age of 43, he married Maria WEICKER, born in Sandweiler in 1887.
The marriage was celebrated in Gröba (Thüringen). PIEPER’s occupation, at the time, was Fabrikdirektor.
PIEPER’s uncle, Adolph PIEPER, was an engineer and founded in 1873 a successful machine construction company in Moers (Rheinland). Adolph died in 1925 and his son Felix (born 1888) took over the business in 1928. The company, however, was closed in the late 1930s.
Was Paul PIEPER employed in the family company, and did he set up as a consulting engineer when the company closed?
Through his later non-Luxembourg patents his places of residence can be retraced as follows:

1938-1943 Luxembourg, 18 rue des Glacis
1945 Nockeby (Stockholm), 42 Solleröuägen
1949 Luxembourg, 32 rue Philippe
1949-1951 Luxembourg, 18 rue des Glacis

Did he leave Luxembourg for Sweden between 1943 to 1949? Did he have Swedish citizenship, as indicated in a British patent of 1949?
PIEPER’s patents relate to a variety of fields:

1938 household goods, such as combs, brushes
1939 injection moulding
1943 reinforced glass
1945 razors
1946 treating/coating metal surfaces

It has been suggested above that PIEPER was an independent engineer; this assumption is based on two of his patents which he assigned to industrial companies.
For the sake of completeness, it has to be pointed out that in the 1920s and 1930s three German patents were granted to a Dipl.-Ing. Paul PIEPER, with residence in Fröndenberg-Ruhr (1929), Breslau (1929) and Magdeburg (1935). Which patent, if any, can be attributed to the inventor of interest to the present study?
Paul PIEPER died in 1957 in Luxembourg-city.

FamilySearch database (GCN1-41N)