In schools nowadays nobody is hearing something about flexible shaft; whereas this small little element can solve so many problems. A short introduction to a cost effective solution to save complicated gears.

A flexible shaft may be employed to transmit force or power through rotation (less likely tension or compression). It is distinguishable from wire rope in that it is not formed of braided or woven bundles of wire fibres. Instead, a flexible shaft is formed by wrapping a succession of layers of wires or strands about a mandrel, core, or central void. Each layer is typically wrapped in opposite direction from the last layer. 

As a result of this wrapped wire layer structure, a flexible shaft is uniquely adapted to transmit power in a push/pull manner, where it tends not to bunch under compression as does wire rope, and in a rotational manner where it resists forming a helix as does wire rope. Yet, and perhaps paradoxically, a flexible shaft is very flexible because of this same structure and is thus well adapted to transmit power through radical bends and other tortuous paths. Flexible shafts have thus found many power transmission applications where the power source must be located remote from the application like speedo meter, weed trimmers, and power seats in vehicles.

A flexible shaft is typically housed in a sheathing or casing for a number of reasons. Typically, such a casing eliminates the potential for abrasion of the flex shaft against structural members or components located adjacent to the flexible shaft. Additionally, the casing eliminates potential for shaft whip or harmonic or periodic deformation which would otherwise occur as the shaft rotates at high speeds. Such flexible shaft cables can than been used as substitution of unprotected or complex drive units like angle gear box, chain hoists, universal joints, etc; or for applications where there is little or no accurate alignment between the power source and the drive part. Another solution can be provided where transmission of mechanical rotary power is not possible in a straight line.

There are hundreds of possibilities and Suhner is a specialist in manufacturing flexible shafts and can assist users find the right solution.

(Suhner India Pvt Ltd, Bangalore. Tel: 080-27831108, 08110-329855. Mobile: 099723-00935. Fax: 91-80-27831109. Email: transmission.in@suhner.com)