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:
Oct. 13, 1992
Filed:
Jan. 25, 1991
Takeshi Toyoshima, Ibaraki, JP;
Mitsuo Ogura, Katsuta, JP;
Hitachi Koki Company Limited, Tokyo, JP;
Abstract
A vacuum pump includes a rotatable cylinder rotatably disposed coaxially around an inner stationary cylinder and in an outer stationary cylinder. The rotatable cylinder has a plurality of recesses defined in inner and outer circumferential surfaces thereof. The outer stationary cylinder has a helical groove defined in an inner circumferential surface thereof. The inner stationary cylinder has a helical groove defined in an outer circumferential thereof. The rotatable cylinder is rotated by a motor to deliver a gas axially along the helical grooves. The recesses are effective to produce turbulent flows in the gas to increase the rate at which the gas is discharged. The recesses have an axial length smaller than the transverse width of helical threads on the outer circumferential surface of the inner stationary cylinder and the inner circumferential surface of the outer stationary cylinder, to minimize any gas leakage across the helical threads.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile