Electricity: measuring and testing – Measuring – testing – or sensing electricity – per se – Frequency of cyclic current or voltage
Patent
1983-04-18
1985-05-07
Krawczewicz, Stanley T.
Electricity: measuring and testing
Measuring, testing, or sensing electricity, per se
Frequency of cyclic current or voltage
G01R 3112
Patent
active
045160686
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The invention of the present patent application refers broadly to the field of apparatus and equipment for testing tires for defects such as punctures and other structural damage which might have been inflicted upon the tread portion of the tire. More specifically, the invention deals with an improved electrode used in a system for testing wherein an electrical potential is imposed across the electrode and a neutral reference electrode and wherein, when a defect is detected, arcing will occur through the defect between the two electrodes. In a preferred embodiment of the invention, the biased electrode is configured for easy insertion into the annular cavity formed between the sidewalls of the tire and into engagement with the underside of the tread portion of the tire.
BACKGROUND OF THE INVENTION
Tires available for commercial sale are generally one of two types: new tires and tires which have been retreaded. Because of the ever escalating cost of new tires, the retreading market has become more appealing to many consumers.
The retreading of used tires serves a significant economical function. Not only does it provide a less expensive product to the consuming public, but it also limits waste which results from the discarding of tire carcasses.
Prior to the conduct of retreading operations upon a used tire carcass, it is necessary to ascertain if any foreign objects are embedded in the tread portion of the tire or if any cracks, fissures, or holes exist therein. The prior art has typically relied upon visual inspection in order to make this determination. If such defects are found to exist, they are cured prior to continuing with retreading operations.
Visual inspection for such defects tends to be slow and time consuming. More importantly, however, this method of searching for defects is, at best, unreliable. With this method, a tire is rotated on a mounting stand, and an inspector visually observes the tread portion of successive tires as they pass beneath his gaze. Although a trained eye might detect defects which would not be apparent to the untrained observer, the monotony of observing the tread portions of successive tires make it difficult, after a period of observation, to reliably spot such defects.
Additionally, some defects are so minute that they escape the detection of even a trained, experienced observer. Nevertheless, even defects of this nature can cause problems if the tires are retreated without proper treatment being given to correct the defects.
In an attempt to solve some of the problems inherent in visual inspection, other types of testing have been devised. One such method involves over inflating the tire to a degree and either immersing the tire in a fluid or applying a fluid to the outer surface thereof. A leak of air through an orifice or fisher can be detected visually more readily by the observation of a bubbling effect which will occur at the location of the defect.
Non-visual systems have come into use in order to augment visual inspection. Ultrasonic systems have, in recent years, become used more frequently for aiding in the detection of defects as previously discussed.
Although the use of fluids to facilitate detection of defects and systems such as ultrasonic systems have made detection searches more reliable, many problems yet exist. Where many tires are processed, it is important to conduct an inspection as expeditiously as possible. Inspections conducted even with the use of fluids and ultrasonic detectors have done little to accomplish more expeditious processing during inspection.
Recently, a system wherein the tread portion of a tire is sandwiched between a pair of electrodes across which a high voltage electrical potential is generated has been discovered. With this system, if objects such as nails are embedded in the tread portion of the tire or if defects such as orifices or fissures exist, the voltage applied across the electrodes will cause arcing at the point of foreign object or defect. In one such system of which applicant is aware, a tire
REFERENCES:
patent: 1779907 (1930-10-01), Dye
patent: 3465242 (1969-09-01), Gruetzmacher et al.
Hawkinson, Jr. Raymond P.
Newman Dennis W.
Krawczewicz Stanley T.
Paul E. Hawkinson Company
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