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:
Jun. 10, 1980
Filed:
Mar. 29, 1978
Applicant:
Inventors:
Alfred E Maskrey, Pittsburgh, PA (US);
Donald H Hockenberry, Trafford, PA (US);
Assignee:
Leybold-Heraeus GmbH & Co. KG, Cologne, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F04D / ;
U.S. Cl.
CPC ...
417 12 ; 417 87 ; 318305 ; 318306 ;
Abstract
A dual speed mechanical rotary vacuum pump wherein a mechanical rotary vacuum pump is directly connected to a two speed electrical motor which drives the pump and the speed of the motor is controlled by an electrical control circuit which selectively causes the motor to rotate at either a first speed for a predetermined period of time or at a second slower speed. The speed of the motor is automatically switched to the slower speed after the predetermined period of time.