The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 22, 1988
Filed:
Apr. 21, 1986
Harry Ferrari, Pittsburgh, PA (US);
Raymond P Harrington, Pittsburgh, PA (US);
Harry W Ingram, Pittsburgh, PA (US);
Ferrari Importing Company, Royal Oak, MI (US);
Abstract
Shock and vibration is suppressed in a racquet having a tubular frame of metal, graphite, fiberglass, or the like, by a bar or column of shock-and-vibration-absorbing material such as foam. The bar is 5 inches to 10 inches in length and is weaved over and under the vertical strings in the region, between the handle and the nearest cross or horizontal string, where a ball or shuttlecock would not impact in normal play. The ends of the bar are brought through the end spaces between the string and the frame of the racquet and tucked under the frame. The bar is composed of layers of the shock-and-frequency absorbing material. The material is soft, light and resilient. The inner layer or layers has a higher density than the outer layer. The frequency for which the maximum absorption occurs decreases progressively from the inner layer or layers outwardly. The resonant frequency of a typical racquet is about 650 hertz. The predominant absorption frequency of the outer layers of the bar is between 500 and 2000 hertz. The inner layer of layers, being of higher density, have maximum absorption at higher frequency and predominantly absorb shock while the outer layers predominantly absorb vibration.