Implements or apparatus for applying pushing or pulling force – Method or apparatus for placement of conductive wire – Conduit snakes
Reexamination Certificate
1999-06-02
2001-09-25
Watson, Robert C. (Department: 3723)
Implements or apparatus for applying pushing or pulling force
Method or apparatus for placement of conductive wire
Conduit snakes
Reexamination Certificate
active
06293519
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for feeding electrical cables through existing structures. In particular, this invention is concerned with an electrician's snake that is visible and easy to locate in the low light environments of ducts, wall cavities and other passages used to house electrical wiring.
Various devices have been employed in the past to facilitate the installation of electrical conductors in conduits, raceways, wall cavities, ceiling plenums and other passageways. Light weight and flexible chains have commonly been used to aid in the feeding of electrical cables. Light weight chains however are only practical for feeding electrical conductors or guidelines where one end of the chain can be lowered from a higher position through a passageway to a lower position. Once one end of the chain is lowered from the higher position to the lower position then the electrical conductor can be attached to the end of the chain and pulled via the chain through the passageway up to the higher position. Another common device often used to ease installation of electrical conductors in passages is an electrician's “snake” or “fish tape”. A conventional snake typically comprises a flattened strip of metal. The snake is typically used to feed cables through a passage by first advancing the snake through the passage, attaching the electrical conductor or guideline to the leading end of the snake and then pulling the snake and attached conductor back through the conductor.
Electrician's snakes of the type described have proven to be difficult to use, especially in passages already occupied with electrical conductors. When using the snake in an empty passageway or duct, there is little chance of the snake becoming tangled or otherwise obstructed. If advancement of the snake through the passage does become encumbered, the snake can be pulled out and another attempt at feeding the snake through the passage can be made without fear of snagging or damaging other electrical conductors. In the case where there are preexisting electrical conductors in the passageway, the snake can and often does become entangled with or otherwise encumbered by the preexisting electrical conductors in the passage. Since the long, narrow and confined passageways housing electrical conductors are dimly illuminated or completely dark it is often difficult or impossible to determine exactly where and upon what the snake is entangled. Even when the end of the snake being advanced through the passageway is relatively near an end opening of the passageway, locating the end of the snake to attach the electrical conductor to be pulled can be difficult due to the dimly lit passageway. Locating the end of the snake is a problem encountered when working in passages with or without other preexisting electrical conductors—the problem is more pronounced in passages having other electrical conductors however. In addition to not being able to determine exactly where and upon what the snake is entangled, the metallic snake may itself become an electrical conductor if the snake comes into contact with an uninsulated electrical conductor, thereby posing a hazard to the operator of the snake.
SUMMARY OF THE INVENTION
In accordance with this invention it is therefore an objective to provide a luminous snake device that aids in the feeding of electrical conductors through an electrical conduit and yet is easy to locate and identify in the dimly lit confines of an electrical conduit or other existing passageway and therefore eases location and use of the snake.
It is a further object of this invention to provide such a luminous snake device wherein the luminous snake device is electrically non-conductive.
It is a further object of this invention to provide such a luminous snake device wherein the luminous snake is easy to manufacture and produce.
It is a further object of this invention to provide such a luminous snake device wherein the luminous snake is preserved by the coating thereon which results in the increased life of the snake.
This invention results from the realization that a higher visibility and therefore a better and easier locating electrician's snake is effectuated by making a snake of a flattened metallic strip coated with a phosphorescent coating. The phosphorescent coating of the present invention is capable of remaining visibly illuminated without ambient light several hours after having been exposed to ambient light. In addition, when the core strip of the luminous snake is coated with a sufficient thickness of the phosphorescent coating material, the phosphorescent coating effectively provides an electrically non-conducive insulating barrier to the luminous snake.
This invention features an electrician's snake comprising a thin and flexible metallic core strip for feeding through electrical conduits; and a phosphorescent coating applied to the core strip that is capable of providing visible illumination in the absence of ambient light long after initially being exposed to ambient light.
The core strip of this invention is typically constructed from a flattened strip of metal. The metal core strip is flexible to the extent that the core strip is capable of folding upon itself This degree of flexibility and resiliency in the core strip allows the snake to have a small bending radius without risk of permanent deformity to the snake. The flexibility, resiliency and small bending radius of the core strip is important to the functionality of the invention since it permits the snake to be fed through passages having numerous and various turns with ease.
The phosphorescent coating of the snake is typically a paint having luminescent properties. The luminescent properties of the phosphorescent coating applied to the core strip are such that the core strip coating, and thus the snake itself, is visible in low ambient light conditions after being initially exposed to light of suitable wavelength.
In another embodiment of the present invention the phosphorescent material of the snake is an integral part of the core strip. That is, the phosphorescent material having luminescent properties is incorporated into the structure of the material comprising the core strip. In this particular embodiment, the luminescent characteristics of the snake are maintained even if the outer surface of the subject invention becomes nicked or otherwise damage. Even if portions of the snake become worn through use, the snake maintains its luminescent properties throughout the entirety of its length.
The terminal ends of this invention may be fashioned in a variety of shapes in order to facilitate (1) the advancement and retrieval of the snake and (2) the attachment of electrical conductors to the end of the snake. As such, one end of the snake may be shaped to facilitate the attachment of electrical conductors or guidelines and the other end of the snake may be shape to facilitate the snake operator's grip on the snake
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patent: 3972386 (1976-08-01), Hayslip
patent: 3979106 (1976-09-01), Jacques
patent: 4724327 (1988-02-01), Mitchell
patent: 5071118 (1991-12-01), Barnett
patent: 5752761 (1998-05-01), Pietruczynik et al.
patent: 5947460 (1999-09-01), Williams
Lambert Gary E.
Lambert and Associates
MacDonald Donald J.
Watson Robert C.
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