Keuffel & Esser, (fl.1867-1982) New York.

German immigrants Wilhelm Johann Diedrich Keuffel (*1838-†1908) and Hermann Esser (*1845-†1908) establish scientific instrument manufacturing firm Keuffel & Esser in New York City in 1867. Best known for its popularization of the slide rule, Keuffel & Esser was the first American company to specialize in the manufacture and sale of drafting and surveying tools. By the early twentieth century, it was one of the largest suppliers of scientific instruments in the world. 

K+E drawing instrument patents

28 Mar 1893 US494132 Esser's patent pivot joint

06 Nov 1894 US528668 Esser's patent locking device 

15 Oct 1901 US684437 Drawing pen with lever [6]

19 Feb 1907 US844772 Straightening device 

01 Dec 1908 US905419 Click pen

08 Jul 1924 US1500246 Straightening device 

19 May 1936 US2041299 Bifurcated drawing instrument

Fig.1. and 2. K+E Lithographic compass set.

Fig.3. and 4. Key Instruments proportional dividers by Keuffel & Esser. Key Instruments (drawing instruments and sets) was a brand marketed by Keuffel & Esser. These proportional dividers, graduated for lines and circles, feature a micrometer bar for accurately setting divisions for line or circle. The bar can also be moved in a position to accurately set the distance betrween the points. Dividers measure 245mm in length.

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NOTES / REFERENCES

[1] Hoboken Historical Museum: Online Collections Database;  Partners in Creating. The First Century of K+E 1867/1967 

[2] Landmarks Preservation Commission KEUFFEL & ESSER COMPANY BUILDING, 127 Fulton Street

[3] K+E Timeline

[4] Wilhelm J.D. Keuffel (1838-1908) 

[5] Keuffel & Esser published a monthly journal called The Compass. Issues for the years 1891-1892 are available on google books. New York Public Library holdings run from 1891 to 1894. 

[6] Also see similar lever pens by Theo Alteneder US568556A and the 'Hebel-Feder' by E.O. Richter (1928 cat p.44.)