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A cable tie or tie-wrap, also known as a hose tie, zap-strap, or zip tie, is a type of fastener, for holding items together, primarily electric cables or wires. Because of their low cost and ease of use, tie-wraps are ubiquitous, finding use in a wide range of other applications. Stainless steel versions, either naked or coated with a rugged plastic, cater for exterior applications and hazardous environments.
The common tie-wrap, normally made of nylon, has a tape section with teeth that engage with a pawl in the head to form a ratchet so that as the free end of the tape section is pulled the tie-wrap tightens and does not come undone. Another version of the tie-wrap allows a tab to be depressed to either adjust the tension or remove the cable tie.
Design and use
The most common cable tie consists of a sturdy nylon tape with an integrated gear rack, and on one end a ratchet within a small open case. Once the pointed tip of the cable tie has been pulled through the case and past the ratchet, it is prevented from being pulled back; the resulting loop may only be pulled tighter. This allows several cables to be bound together into a cable tree.
A cable tie tensioning device or tool may be used to apply a cable tie with a specific degree of tension. The tool may cut off the extra tail flush with the head in order to avoid a sharp edge which might otherwise cause injury.
In order to increase resistance to ultraviolet light in outdoor applications, a specific grade of nylon containing a minimum of 2% carbon black is used to protect the polymer chains and extend the cable tie's service life. Blue cable ties are supplied to the food industry and contain a metal additive so they can be detected by industrial metal detectors. Cable ties made of ETFE (Tefzel) are used in radiation-rich environments. Red cable ties made of ECTFE (Halar) are used for plenum cabling.
Cable ties can be used as makeshift handcuffs. Specially constructed physical restraints called PlastiCuffs, based on the cable tie design, are used by police and military to restrain prisoners. Cable ties are also sometimes used to prevent hubcaps (also known as wheel trims) from falling off a moving vehicle, and some are sold specifically for this purpose.
Cable ties were first invented by Thomas & Betts, an electrical company, in 1958 under the brand name Ty-Rap. Initially they were designed for airplane wire harnesses. The original design used a metal tooth, and these can still be obtained. Manufacturers later changed to the nylon/plastic design.[self-published source]
The design has over the years been extended and developed into numerous spin-off products.
Ty-Rap cable tie inventor, Maurus C. Logan, worked for Thomas & Betts and finished his career with the company as Vice President of Research and Development. During his tenure at Thomas & Betts, he contributed to the development and marketing of many successful Thomas & Betts products. Logan died in November 2007, at age 86.
The idea of the cable tie came to Logan while touring a Boeing aircraft manufacturing facility in 1956. Aircraft wiring was a cumbersome and detailed undertaking, involving thousands of feet of wire organized on sheets of 50-foot long plywood and held in place with knotted, waxcoated, braided nylon cord. Each knot had to be pulled tight by wrapping the cord around one's finger which sometimes cut the operator's fingers until they developed thick calluses or "hamburger hands." Logan was convinced there had to be an easier, more forgiving, way to accomplish this critical task.
For the next couple of years, Logan experimented with various tools and materials. On June 24, 1958, a patent for the Ty-Rap cable tie was submitted.
Cable ties are generally viewed as single-use devices; they are typically cut off rather than loosened and reused. However, if a closed loop needs to be opened again, rather than destroying the cable tie by cutting, it may be possible to release the ratchet from the rack. While some cable ties are designed for reuse with a tab that releases the ratchet, in most cases a sewing needle or similar object (for example a small screwdriver) will need to be interposed between the ratchet and the rack. Ties reused in this way will be weaker than new ones.
To open without cutting, the ratchet box can be crushed vertically using pliers.
Types of specialty cable ties
- Beaded cable ties: Unique beaded design allows them to be releasable and reusable
- Releasable cable ties: Easy to apply and remove, reusable
- Ladder style cable ties: Ideal for intermediate bundling and retail applications
- Identification cable ties: Built-in flags for written or printed identification
- Parallel entry cable ties: Tamper-proof, low profile heads
- Tear-off cable ties: Quick release design requires no cutting tools
Other methods of bundling cable together securely and semi-permanently include cable lacing, binding knots such as the surgeon's knot or constrictor knot, Velcro brand hook-and-loop strips, conveyor belt hooks, twist ties, Rapstrap fasteners, metal buckle clips or Cablox cable management.
- The name probably comes from the installation of a cable tie which produces a "zip" sound as the pawl rides the slope of teeth.
- See the Thomas and Betts official website.[dead link]
- Maurus C. Logan, "Cable bundling and supporting strap",U.S. Patent 3,022,557, filed 24 June 1958, issued 27 February 1962.
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