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:
May. 27, 1980
Filed:
Feb. 22, 1978
William L Sheppard, Romulus, MI (US);
AVM Corporation, Jamestown, NY (US);
Abstract
Disclosed is a vacuum pump device that is adapted to create a vacuum source from a source of high pressure air. The device comprises a piston actuated in one direction by compressed air and in the opposite direction by a power return spring. The compressed air moves the piston to load the spring and the spring moves the piston to create a vacuum. A special dumping valve is also provided which is actuated toward the end of the return stroke of the piston to cause a sudden increase in the pressure differential across the piston to prevent stalling of the piston when loading is such that the piston moves very slowly, thereby assuring that the vacuum pump will cycle as often as is necessary to maintain the desired vacuum.