Electrical connectors – With or having flexible guard or support for cable or conductor – Resilient
Reexamination Certificate
2003-02-18
2004-12-07
Zarroli, Michael C. (Department: 2839)
Electrical connectors
With or having flexible guard or support for cable or conductor
Resilient
C174S135000
Reexamination Certificate
active
06827601
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a cord guard for a household appliance. The cord guard is used to minimize stress on a power cord that might occur as a result of frequent movements of the appliance. Cord guards in accordance with this invention may advantageously be used for household irons and could be used for other appliances such as hair dryers, small vacuum sweepers.
INCORPORATION BY REFERENCE
The disclosures of the each of the following US patents are incorporated by reference herein.
Baldacci U.S. Pat. No. Des. 302,883
Brady et al. U.S. Pat. No. Des. 430,371
Pyle U.S. Pat. No. 5,823,817
Czerner et al. U.S. Pat. No. 5,768,808
Beverly et al. U.S. Pat. No. 6,276,078
BACKGROUND OF THE INVENTION
Repeated flexing of an appliance power cord often ultimately leads to failure of the power cord. Power cord failures can take various forms, such as broken insulating jackets, exposed bare wires, broken wires, and internal electrical shorts. Cord guards can substantially extend the number of times power cords can be flexed without failure.
The portion of a power cord closest to an appliance to which the cord is attached is the portion usually most subjected to being bent during operation of the appliance. This portion is also subjected to substantial bending stresses when the power cord is wrapped around the appliance for storage. For this reason, a cord guard typically comprises a first, relatively fixed, end connected to the appliance, a second, free end, and a flexible, tubular mid-section intermediate the two ends.
In general, a cord guard is designed to prevent extreme bending of a power cord so that the power cord extends along a path without sharp bends or kinks. Accordingly, the mid-section of the cord guard must have some flexibility to permit the power cord to bend to a limited extent but should be sufficiently stiff to resist being sharply bent so that the portion of the power cord within the cord guard also has no sharp bends.
Cord guards have been molded from thermoplastic elastomer (TPE) materials, such as Santoprene. However, TPE materials are more expensive than many other plastic materials and can be difficult to work with. Polypropylene, an inexpensive plastic material, has been used successfully for molding cord guards. However, polypropylene is a relative rigid material and there are occasions when greater flexibility is required than can be obtained satisfactorily with prior cord guard designs. Added flexibility could be obtained by making a cord guard with thinner, walls, but that could reduce the useful life of the cord guard. Therefore, it can be difficult to provide inexpensive cord guards which are both long lasting and adequately flexible, yet resistant to excessive flexing.
SUMMARY OF THE INVENTION
An object of this invention is to provide a new cord guard which can be highly flexible yet resistant to excessive bending, and have a satisfactory useful life.
A cord guard made in accordance with this comprises a one-piece molded, hollow plastic tubular member having a first, relatively fixed, end shaped to be connected to an appliance, a second, free end, and an intermediate, power cord-confining tube. The entire cord guard is hollow so that, when connected to an appliance, the appliance power cord extends therethrough. The plastic material used to produce the cord guard is relatively rigid but the power cord-confining tube is so formed as to provide adequate flexibility. Various thermoplastic materials could be used in molding the cord guard, provided they are relatively rigid but capable of flexing. Polypropylene is an excellent material for this purpose because it is readily available, readily worked with, and inexpensive.
The intermediate, power cord confining tube is formed from a pair of wall members each of which has a series of stepwise and spirally extending panels. The panels of one of the wall members intertwines with the panels of the other of the wall members and both horizontal and vertical gaps are located between adjacent panels. (As used herein, “horizontal” refers to a direction transverse to the longitudinal axis of the cord guard and “vertical” refers to a direction parallel to the longitudinal axis of the cord guard.) In use, the intermediate tube readily flexes to a limited extent as needed by a spreading apart of the panel section margins that form the horizontal gaps.
Other objects and advantages will become apparent from the following description and the accompanying drawings.
REFERENCES:
patent: 3093432 (1963-06-01), King
patent: 3395244 (1968-07-01), Koehler
patent: 3497608 (1970-02-01), Elliott et al.
patent: 4203004 (1980-05-01), Cox
patent: D302883 (1989-08-01), Baldacci
patent: 5170016 (1992-12-01), Liu et al.
patent: 5300732 (1994-04-01), Wambeke et al.
patent: 5451171 (1995-09-01), Dickie
patent: 5768808 (1998-06-01), Czerner et al.
patent: 5823817 (1998-10-01), Pyle
patent: D404363 (1999-01-01), Pyle
patent: D430371 (2000-08-01), Brady et al.
patent: 6140584 (2000-10-01), Baldissara
patent: D439564 (2001-03-01), Huang
patent: 6265668 (2001-07-01), Liu
patent: 6276078 (2001-08-01), Beverly et al.
patent: 6309229 (2001-10-01), Sinclair
patent: 6431904 (2002-08-01), Berelsman
Photograph of cord guard assembled on a Black & Decker iron which came to applicant's attension prior to the filing of the instant application.
Copending design patent application No. 29/175,895 of Robert J. Haeberle filed Feb. 12, 2003.
Dybvig Roger S.
Hamilton Beach, Proctor-Silex, Inc.
Zarroli Michael C.
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