Updated 17-XI-2018

Bernie Lee Benbow

This article was written by fellow lamp engineer and collector Edward J. Covington, and originally appeared on his own website of biographical sketches of persons involved in the lamp industry. Following his passing in February 2017, and with kind permission of his family, Ed's words have been preserved here in the hope of maintaining access to his writings for the benefit of subsequent generations.

Bernie Lee Benbow

Burnie Lee Benbow (4 Jul 1885 - 7 Apr 1976) was, for many years, the Manager of the Cleveland Wire Works, GE Lighting, in Cleveland, Ohio. His contributions were many and he was the first to receive a patent on the coiled-coil tungsten filament. At first this was trialled in some compact-filament projection lamps but the performance was not entirely satisfactory due to difficulties in maintaining the precise geometry at high filament operating temperatures. The metallurgical and manufacturing problems were eventually overcome by the British General Electric Company who introduced the first coiled-coil general lighting lamps in 1933-34, followed quickly by the British Thomson-Houston company, a wholly-owned subsidiary of GE of America. The same technology was introduced in the United States in 1936 and resulted in a marked improvement in incandescent lamp efficacy.

Benbow was responsible for hiring Zay Jeffries, a metallurgist, in 1914. In 1963 Jeffries said of Benbow:
"Benbow was an unusual manager. He was probably about a generation ahead of his time. He was bold enough to risk the cost of research, had the imagination to help guide the studies, and the ability to utilize research findings." "Benny" Benbow was a native of New Castle, Indiana; he was the son of James and Belle (Van Dorn) Benbow. Benbow joined the Engineering Department of the National Electric Lamp Association in 1909, was made foreman in the Wire Drawing Department in 1911 and was then elevated to the position of Manager of the Cleveland Wire Works in 1913.
Keating1 said the following regarding Benbow's 1917 patent:
"In 1917 B. L. Benbow, manager of the Cleveland Wire Works (a part of National), had obtained a patent on coiling the wire twice, to make what could be called a 'coiled-coil' filament. Double coiling had been used for some projection lamps. However, its application to the smaller filaments used in standard lamps presented numerous difficulties for years after Benbow obtained his patent. Double coiling required very precise tolerances. Each tiny coil had to be spaced perfectly so that current would not jump from one coil to the next. There were problems in removing the mandrels or forms on which the wire was coiled . Experimental work went forward but it was not until the middle thirties that the Nela Park research workers and the Wire Works men could figure out completely practical methods for commercial production."

Coiled-coil filament scanned from U. S. Patent No. 1,247,068

  1. US 1,168,050 - Wire Drawing (11 Jan 1916).
  2. US 1,247,068 - Coiled-Coil Filament (20 Nov 1917).
  3. US 1,686,063 - Packing and Process of Making Same (2 Oct 1928).
  4. US 2,114,171 - Swaging Machine (12 Apr 1938).

References & Bibliography
  1. "Lamps for a Brighter America", P.W.Keating, McGraw-Hill Book Co., New York, 1954, pp.151-152.
  2. "Book of the Incas", National Lamp Works of General Electric, 1928.
  3. "Makers of National - The Spirit and People of an Industrial Organization", E.J.Covington, NELA Press, GE Lighting, Cleveland, Ohio, 1997.