Electricity: electrical systems and devices – Discharging or preventing accumulation of electric charge
Reexamination Certificate
1999-09-03
2001-04-10
Sherry, Michael J. (Department: 2836)
Electricity: electrical systems and devices
Discharging or preventing accumulation of electric charge
C361S220000
Reexamination Certificate
active
06215639
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
(Not Applicable)
STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT
(Not Applicable)
BACKGROUND OF THE INVENTION
The present invention generally relates to a buckle system for an electrically conductive bracelet, and more particularly to an improved buckle system that prevents a dangling endpiece of the bracelet from inadvertently contacting a source of electrical potential.
Buckle systems for electrically conductive bracelets are well known and in wide use throughout the electronics industry as well as other industries. During the assembly of electrical equipment, considerable difficulties may be encountered because components such as integrated circuits, for instance, may be disabled or destroyed by over-voltage or power density resulting from static electricity. Certain junctions in such circuits can be destroyed by as little as 50-volt potential, which radically changes the doping structure in their lattices.
A person walking on a carpet on a dry day can accumulate as much as 30,000 volts of potential, and can electrically generate thousands of volts by simply changing position in a chair or handling a styrofoam cup. Such a person can unintentionally discharge static electric potential into a circuit or component by touching it and causing over-voltage or excessive power density.
More and more frequently, personnel in industries, in which integrated circuits and other microelectronic components are handled or assembled, are taking measures to limit the failure rate of those circuits and components by attempting to keep both themselves and their environment at a zero electrical potential. Such measures include providing workers and work stations with anti-static carpet, conductive or dissipative grounded desk top work surfaces, hot air ion generators which emit ions to neutralize static charges, and electrically conductive bracelets worn by workers to keep workers at a zero potential.
Electrically conductive bracelets proved to be effective in keeping workers at a zero potential, especially when used with other anti-static measures as specified above. A manufacturer typically must depend upon the effectiveness of these bracelets to maintain a lower failure rate of such electronic circuits and components.
Electrically conductive bracelets should be electrically insulating on their exterior surfaces in order to reduce the hazard to a user from inadvertent contact of the bracelets surface with a source of electrical potential. The interior circumferential surface of the bracelet is intentionally made to be an excellent electrical conductor and in contact with the user. If the bracelets outer surface were to be conductive, and were in electrical contact with the inner circumferential surface, then a hazardous path of electrical current conduction to the body might be presented.
Accordingly, these considerations of selective conductivity have been recognized, and have been addressed by several types of electrically conductive bracelets, as disclosed and described in U.S. Pat. No. 4,878,148 to Hee, entitled CROCHETED FABRIC ELASTIC WRIST BRACELET BEARING AN INTERIOR CONDUCTIVE YARN, the teachings of which are incorporated herein by reference.
However, although the electrically conductive bracelets continued to improve, the mechanisms employed to secure these bracelets to a user have not. The electrically conductive bracelets in the above incorporated patent use a buckle that adjoins the two ends of the bracelet. More specifically, one end is inserted through the buckle to protrude outward through an aperture away from the user. As a result, this particular end is left dangling from the bracelet. The dangling end may be lengthy, depending on the limb size of the user.
These dangling ends have no useful purpose whatsoever, but rather subject the user to dangers that can be prevented with the application of the present invention. If the end is left to dangle freely, the risk of catching the same an a piece of electrical equipment is substantially increased. Electrocution is a possibility when the dangling end is accidentally caught in the electrical equipment, especially if the equipment is not grounded properly.
The dangling end may further subject the user to additional dangers in a chemical environment integrated to the above setting. The dangling end may contact a chemical that can be irritable to the skin, or even possibly toxic. The user may not be aware of the whereabouts of the dangling end since it is not a fixture that is closely contiguous to his body. Therefore, along with the possibility of electrocution, the user may be subjected to chemical poisoning as well.
In order to mitigate the above dangers, the users have frequently resorted to hiding the dangling end by tugging it into the bracelet. However, as stated previously, the material for the bracelet needs to be made with a highly conductive material. Therefore, tugging the dangling end into the bracelet tends to cut off at least a portion of the conductive contact between the bracelet and the user, thereby compromising the effectiveness of the bracelet for user safety.
Moreover, the users have also tried to alleviate the dangers by simply cutting off the dangling end. However, this method is also unsound because not only does it considerably decrease the effectiveness of the bracelet, the bracelet tend to deteriorate as well. More specifically, the materials for the bracelet tend to run, especially if the bracelets are composed of fabric as specified in the above incorporated patent.
Thus, there has long been a need in the industry, and in the microelectronics business in particular, for a method and an apparatus for preventing the dangling end of the bracelet from exposing the user to the above-described dangers. In particular, there is a need for a mechanism to affix the electrically conductive bracelet to the user without having the end dangerously dangling away from the bracelet, while simultaneously posing minimum inconvenience to the user by being easily adjustable to alternate sizes of the limb.
The present invention addresses and overcomes the above-described deficiency of prior art electrically conductive bracelets by providing a buckle system that is configured to place the end underneath the bracelet, rather than having the end dangling freely. Moreover, the bracelet is simultaneously user-friendly by having the end further attached to a strap puller for ease of adjustment. In this respect, not only does the present invention significantly reduce the risk of danger, but may also increase user comfort to provide minimum temptation to remove the bracelet to cause unintended damage to the workpiece.
BRIEF SUMMARY OF THE INVENTION
In accordance with a preferred embodiment of the present invention, there is provided an adjustable buckle system for preventing a dangling endpiece of an electrically conducting bracelet affixed around a persons limb from inadvertently contacting a source of electrical potential. The adjustable buckle system of the preferred embodiment comprises a grounding strap having a first end and a second end configured to slidably engage each other to form a plurality of alternate sizes.
Connected to the first end of the strap is an electrically insulating buckle. The electrically insulating buckle is further configured to secure the bracelet in one of the plurality of alternate sizes. In addition, a strap puller is attached to the second end of the grounding strap. More specifically, the strap second end is sewn to the strap puller. The puller is further configured to slidably engage the strap to facilitate adjustments of the bracelet to form the plurality of alternate sizes.
In accordance with a preferred embodiment of the present invention, the grounding strap is a crocheted fabric elastic grounding strap. Moreover, the grounding strap further comprises an inner surface and an outer surface. The strap inner surface is disposed circumferentially toward the limb, whereas the strap outer surface is disposed circumferentially away from the limb. Th
Sherry Michael J.
Stetina Brunda Garred & Brucker
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