Bowden cable

A Bowden cable (/ˈbdən/ BOH-dən) is a type of flexible cable used to transmit mechanical force or energy by the movement of an inner cable relative to a hollow outer cable housing. The housing is generally of composite construction, consisting of an inner lining, a longitudinally incompressible layer such as a helical winding or a sheaf of steel wire, and a protective outer covering.

The linear movement of the inner cable is most often used to transmit a pulling force, although push/pull cables have gained popularity in recent years e.g. as gear shift cables. Many light aircraft use a push/pull bowden cable for the throttle control, and here it is normal for the inner element to be solid wire, rather than a multi-strand cable. Usually provision is made for adjusting the cable tension using an inline hollow bolt (often called a "barrel adjuster"), which lengthens or shortens the cable housing relative to a fixed anchor point. Lengthening the housing (turning the barrel adjuster out) tightens the cable; shortening the housing (turning the barrel adjuster in) loosens the cable.

The origin and invention of the Bowden Cable is open to some dispute, confusion and popular myth.

The invention of the Bowden cable has been popularly attributed to Sir Frank Bowden, founder and owner of the Raleigh Bicycle Company who, circa 1902, was reputed to have started replacing the rigid rods used for brakes with a flexible wound cable. There appears to be no current definitive reference for this.

The Bowden mechanism was invented by Irishman Ernest Monnington Bowden (1860 to April 3, 1904) of 35 Bedford Place, London, W.C. The first patent was granted in 1896 (English Patent 25,325 and U.S. Pat. No. 609,570), and the invention was reported in the Automotor Journal of 1897 where Bowden's address was given as 9 Fopstone Rd, Earls Court. The principal element of this was a flexible tube (made from hard wound wire and fixed at each end) containing a length of fine wire rope that could slide within the tube, directly transmitting pulling, pushing or turning movements on the wire rope from one end to the other without the need of pulleys or flexible joints. The cable was particularly intended for use in conjunction with bicycle brakes, although it had the potential for other applications. The Bowden Brake was launched amidst a flurry of enthusiasm in the cycle press in 1896. It consisted of a stirrup, pulled up by the cable from a handlebar mounted lever, with rubber pads acting against the rear wheel rim. At this date bicycles were fixed wheel, additional braking being offered by a 'plunger' brake pressing on the front tyre. The Bowden offered extra braking power still, and was novel enough to appeal to riders who scorned the plunger arrangement, which was heavy and potentially damaging to the (expensive) pneumatic tyre. The problem for Bowden was his failure to develop effective distribution networks and the brake was often incorrectly, or inappropriately fitted, resulting in a good number of complaints being aired in the press. Its most effective application was on those machines fitted with Westwood pattern steel rims which offered flat bearing surfaces for the brake pads.

The potential of the Bowden cable and associated brake was not to be fully realised until the free-wheel sprocket became a standard feature of bicycles, over the period 1899-1901, and increasing numbers of applications were found for it, such as gear change mechanisms. Importantly in 1903, Hendee developed the twist-grip throttle using a similar cable for his 'Indian' motorcycles. Its lightness and flexibility recommended it to further automotive use such as clutch and speedometer drive cables.

This page was last edited on 20 May 2018, at 01:27.
Reference: under CC BY-SA license.

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