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:
Jan. 22, 1980
Filed:
Jul. 19, 1978
Jonathan W Hinton, Birmingham, MI (US);
Champion Spark Plug Company, Toledo, OH (US);
Abstract
An improved method for producing a ceramic insulator is disclosed. The method comprises the steps of charging ceramic batch into a longitudinally extending die in which stepped arbors are supported by a plunger, forming a blank by pressing the batch between the arbor plunger and an opposing plunger, ejecting the blank and removing the arbors therefrom, contouring the blank to a desired shape, and firing the contoured blank. The insulator has a length-to-diameter ratio greater than 3:1 but not greater than 8:1; the improvement constitutes controlling the relative movements of the opposing plungers with respect to the longitudinal wall of the die during pressing of the blank so that at least 80 percent of the total plunger movement is in the direction of decreasing arbor diameter whereby variations in the end-to-end density of the insulator are minimized. Where 80 percent to 90 percent of the plunger movement is in the recited direction, a further improvement involves contouring the longitudinal surface of the blank to form generally a solid of revolution about the longitudinal axis of the blank wherein the diameter of the blank is greater than the desired fired diameter by a percentage which varies as an inverse function of the end-to-end density of the blank in order to achieve the desired longitudinal surface contour for the fired blank.