A tether is a cord, fixture, or flexible attachment that characteristically anchors something movable to something fixed; it also may be used to connect two movable objects, such as an item being

towed Towing is coupling two or more objects together so that they may be pulled by a designated power source or sources. The towing source may be a motorized land vehicle, vessel, animal, or human, and the load being anything that can be pulled. ...

by its tow. Applications for tethers include:

fall arrest system Fall arrest is the form of fall protection which involves the safe stopping of a person already falling. It is one of several forms of fall protection, forms which also include fall guarding (general protection that prevents persons from enteri ...

s, lanyards, balloons, kites, airborne wind-power systems,

anchor An anchor is a device, normally made of metal, used to secure a vessel to the bed of a body of water to prevent the craft from drifting due to wind or current. The word derives from Latin ', which itself comes from the Greek (). Anch ...

s, floating water power systems, towing, animal constraint,

space walks Space is a three-dimensional continuum containing positions and directions. In classical physics, physical space is often conceived in three linear dimensions. Modern physicists usually consider it, with time, to be part of a boundless fou ...

power kite A power kite or traction kite is a large kite designed to provide significant pull to the user. Types The two most common forms are the foil, and the leading edge inflatable. There are also other less common types of power kite including rig ...

ing, and

anti-theft Anti-theft systems protect valuables such as vehicles and personal property like wallets, phones, and jewelry. They are also used in retail settings to protect merchandise in the form of security tags and labels. Anti-theft systems include devices ...

devices.

Failure

Failure mode Failure causes are defects in design, process, quality, or part application, which are the underlying cause of a failure or which initiate a process which leads to failure. Where failure depends on the user of the product or process, then human er ...

s for tethers are considered in their design. A cord or rope tether may reach its

breaking strength Fracture is the appearance of a crack or complete separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity sur ...

and fail. Outcomes can include an injury or fatal fall, and damage or loss of life to personnel or bystanders caused by backlash of the ruptured segments. Failure-prevention may be designed into a tethering system. Some

safety harness A safety harness is a form of Personal protective equipment, protective equipment designed to safeguard the user from injury or death from falling. The core item of a fall arrest system, the harness is usually fabricated from rope, Wire rope, bra ...

es are used in combination with a shock-absorbing

lanyard A lanyard is a length of cord, webbing, or strap that may serve any of various functions, which include a means of attachment, restraint, retrieval, activation, and deactivation. A lanyard is also a piece of rigging used to secure or lowe ...

, which has break-away stitching designed into it to prevent material failure and regulate

deceleration In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Acceleration is one of several components of kinematics, the study of motion. Accelerations are vector quantities (in that they have magnit ...

, thereby preventing a serious

G-force The g-force or gravitational force equivalent is a Specific force, mass-specific force (force per unit mass), expressed in Unit of measurement, units of standard gravity (symbol ''g'' or ''g''0, not to be confused with "g", the symbol for ...

injury to the user when the end of the rope is reached. Designed-to-fail safety links are sometimes used to prevent excessive tension in a tether involved in towing objects, such as

sailplane A glider or sailplane is a type of glider aircraft used in the leisure activity and sport of gliding (also called soaring). This unpowered aircraft can use naturally occurring currents of rising air in the atmosphere to gain altitude. Sailplan ...

s. A signal tether is a system in which a constant signal designates a positive condition, and its interruption, whether by discontinuation or jamming, conveys a failure. The signal may be electrically generated, or a physical device such as flying a flag.

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* by TechSander.com {{tech-stub Hardware (mechanical)

Failure

See also

References

External links