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A flexible shaft is a device that allows powered or manual rotary motion to be transferred along a non-linear route. This flexibility allows the drive from electric motors, engines and manual dials or cranks to be turned in any direction and cross — or even pass through — obstacles. Flexible shaft drives may transfer power and torque or simple motion alone, depending on the application. The drive motion is transferred by a steel coil or wire rope that is fitted with various machine or tool fittings on either end. This drive mechanism may be exposed or enclosed within a flexible, non-rotating sheath.
Many rotary motion drive applications need a degree of flexibility in the route followed between the drive source and the point of work. The plumbers snake is a good example of this requirement and also demonstrates the principles of the flexible shaft. This piece of equipment consists of an electric or gasoline motor that drives a tool attachment via a spring-like steel coil enclosed in a sheath. The flexible nature of the drive shaft allows the plumber to feed the tool through fairly complex piping systems with ease. Once the tool end of the shaft has reached the blockage the motor is started and its rotary output is transferred to the tool, removing the offending obstruction.
Flexible shafts may transfer power or just simple motion. The plumbers snake is an example of power transfer wherein a certain amount of torque is applied to the tool or attachment. Flexible shafts are capable of handling considerable torque and are often used to transfer the drive output of engines in small vehicles. In the case of a flexible shaft potentiometer, however, the shaft only transfers motion with no torque involved. These shafts are often used to connect external dials with remotely located potentiometers that are misaligned with the dial position.
The range of applications possible with a flexible shaft is considerable. Many machining applications use fixed motors with flexible shaft drives that allow operators to freely move a rotary tool bit around a work piece without moving the heavy motor. These applications include die grinders, disc grinders and drills and represent only a few of the many types of final drive fittings available. Flexible shaft drives are also available with drill chucks, cutting or grinding disc attachments, magnetic tool bit fittings and a host of other application-specific fittings. They may also feature multi-purpose clamps or fittings that can be user adjusted to suit individual needs.