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. 05, 1991
Filed:
May. 31, 1989
Steven C Moore, Mountain View, CA (US);
Other;
Abstract
A lapping apparatus of the 'planetary' type that laps a workpiece to a true flat surface instead of to the domed surface characterizing the prior art: it includes a mechanism for spinning and orbiting the workpiece against a lapping disk that has a 360-degree mid-radial portion formed to abrade less rapidly than the radially inboard and outboard portions thereof. In one embodiment, the inboard and outboard portions of the disk are partly or entirely cut away (i.e., recessed) so as to present equal or smaller lapping surface areas than that of the mid-radial portion of the disk. In another embodiment, the abrading surfaces of the disk are formed as raised lands each of which has a shape derived as the mean length, at each orbiting radius, of the orbiting arcs that are swept by the disk across the workpiece while the workpiece is spinning through at least one full revolution. In another form, the lands are made narrower and more numerous, but have the same proportions along the various orbiting arcs. In another embodiment, the lands are made smaller in orbiting arcuate dimension everywhere but at the mid-radius. In another form, various arcuate slices of the lands are staggered with respect to one another. In another form, the disk is grooved in patterns of concentric circles or continuous spirals to provide an analogous effect. In still another form, the mid-radial portion of the disk is made with a ring of more wear-resistant material (e.g. steel) than the inboard and outboard portions (e.g. cast iron).