The Bendix drive: a Chicago patent that built a South Bend empire

1910–1920 · US 1,125,935 AND THE SELF-ENGAGING STARTER DRIVE

The patent's face: The most consequential single invention in this section after Oliver's is the Bendix drive, and this section prints its geography without varnish: the patent is a Chicago document. Letters Patent No. 1,125,935, "Starter for Engines," was filed 2 May 1914 and granted 26 January 1915 to Vincent Bendix, "of Chicago, in the county of Cook and State of Illinois" — the residence line on the face of the patent. Vincent Hugo Bendix was a Swedish immigrant who had worked on his starter mechanism since about 1910, and the problem it solved was the electric starter's weak joint. Charles Kettering's Delco system had put an electric cranking motor on the 1912 Cadillac, and the claim sometimes heard, that Bendix invented the electric starter, fails against that record: the starter was Kettering's.

What no one yet had was a drive that would throw the starter's pinion into the flywheel's ring gear the instant the motor turned, hold it there while cranking, and kick it out of mesh the moment the engine fired and began to outrun the starter — automatically, with no sliding pinion for the driver to manage and no wrecked teeth when the engine backfired or overran. Bendix's answer was mechanical elegance: the pinion rides loose on a shaft cut with a coarse triple-thread screw; switched on, the pinion's own inertia makes it lag the spinning shaft, and the screw thread screws the lagging pinion forward into mesh with the flywheel; when the engine fires and drives the pinion faster than the shaft, the same thread screws it back out, and a spring cushions and completes the disengagement.

The follow-on patents map the refinement, all Chicago-faced: No. 1,172,864 (22 February 1916); Nos. 1,299,418 and 1,299,419 (filed 29 June 1917, granted 8 April 1919); No. 1,327,132, "Engine-Starter" (6 January 1920); No. 1,330,834 (filed 19 December 1917, granted 17 February 1920); and No. 1,345,576 (filed 16 December 1918, granted 6 July 1920). Manufacture began under license at the Eclipse Machine Company of Elmira, New York, in 1913 — Eclipse could cut the triple-thread screw — and the drive's first production automobile was Chevrolet's 1914 "Baby Grand," of which some 5,500 were built that year. By 1919 a million and a half Bendix drives had been made, and "Bendix drive" had become the generic name for the device across the industry. The South Bend chapter began with the money the drive earned: Bendix organized in Chicago in 1919 and in 1924 consolidated his operations in this city, which the brakes entry that follows takes up.

Britannica's summary of the scale — more than 5,500 patents held by Bendix or his company — is printed as the corporate count it is, not as one man's hand. On the inventor's own dates the records disagree by a year: 12 August 1881 in Britannica, the encyclopedias, and the standard biography; 12 August 1882 in some trade-press profiles and in the telling this history's Businesses section carried — both are printed here, unmerged, the encyclopedia date carrying the greater weight.

Sources:

1. U.S. Patents Nos. 1,125,935 (filed 2 May 1914, granted 26 January 1915), 1,172,864, 1,299,418, 1,299,419, 1,327,132, 1,330,834 and 1,345,576 — the patent documents themselves, via the Patent Office images and Google Patents: Vincent Bendix of Chicago; the triple-thread, inertia-engaged, overrun-released mechanism as the specifications describe it.
2. Encyclopaedia Britannica, "Vincent Bendix" — the 1919 corporation, the 1924 South Bend consolidation, the 5,500-patent corporate count, and the 12 August 1881 birth date.
3. The Bendix drive histories (Eclipse Machine Company licensing, 1913; the 1914 Chevrolet Baby Grand; 1.5 million units by 1919) as carried in the automotive-technology literature and the FreightWaves pioneer profile — the latter also the source of the 1882 birth-year variant printed in the text.
4. The Kettering/Delco record (1912 Cadillac electric cranking system) — the starter's invention, against which the Bendix claim to it fails.