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:
Jul. 10, 2001
Filed:
Jun. 08, 2000
Industrial Technology Research Institute, Hsinchu, TW;
Abstract
A double screw rotor assembly includes two screw rotors meshed in a bushing inside a casing. The threads of the screw rotors have a uniform pitch, and define with the bushing a plurality of air chambers in the pitch. The volumes of the air chambers reduce gradually from the inlet toward the output due to the reduce of tooth high so that the outer diameter defined by the tooth tip of the thread of each screw rotor has the shape of an invertedly disposed cone. Adjustable spring means is provided to impart an axial spring force to the bushing relative to the casing, guide means is provided to guide axial movement of the bushing relative to the casing, and a O-ring is disposed between the top wall of the bushing and the casing. Adjusting the pre-loading of the spring means controls the dimension of the clearance between the inside wall of the bushing and the tooth tip of the thread of each screw rotor. The top wall of the busing forces the O-ring against the casing to maintain an airtight condition, so as to improve the working efficiency.