Heinrich Söhnlein founded his toy factory in 1870 in Nuremberg. It was in the beginning a small firm, with a workforce of 5 men, which grew to 25 by 1896. There is very little information about the company after this date; possibly HS worked solely for export firms in Nurenberg and Fürth or there was contract manufacturing for other, more well-known manufacturers.

In 1873 HS received an honorable mention at the Vienna World Exhibition, where he showed a locomotive with tender and four coaches and was described as a producer of tin toys, especially of steam engines, ships and locomotives.

Until the turn of the century, the products were primarily steam toys such as steam and hot-air engines, steamboats, locomobiles and spirit locomotives. The trademark was similar to that of Ernst Plank, but  with the letters H.S. instead of E.P.

In 1903 Heinrich’s son Karl is listed as managing director of the firm. There are Gebrauchsmuster (utility models) from 1910 and 1913 for flying toys; possibly no longer steam toys but only mechanical tin toys were produced.

In the Nuremburg address book of 1934 Karl Söhnlein is listed as a ‘former manufacturer’.

According to Cieslik’s 'Lexicon of the German Tin Toy Industry' the firm Heinrich Söhnlein is last mentioned in 1930.