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:
Apr. 03, 1979
Filed:
Jan. 28, 1977
Masaru Iguchi, Katsuta, JP;
Hitachi, Ltd., , JP;
Abstract
A vacuum operated device is provided with a first vacuum chamber defined by a part of a casing and a first diaphragm; a second vacuum chamber defined by the first diaphragm, another part of the casing, and a second diaphragm; and a rod. The first vacuum chamber communicates with a vacuum source and the second vacuum chamber also communicates with the vacuum source through a changeover valve by which the second vacuum chamber is subjected to the vacuum from the vacuum source or to atmospheric pressure. The rod is secured to the first and second diaphragms at the central portions thereof thereby being axially movable according to the movement of the first and second diaphragms. The vacuum operated device further is provided with a first spring for subjecting the first diaphragm to a spring force opposite to the force that is exerted on the first diaphragm by the vacuum in the first vacuum chamber, and a second spring arranged functionally in series with the first spring for subjecting the rod to a force opposite to the force exerted on the rod by the first and second diaphragms, whereby the rod can be made to have two modes of movements thereby providing different kinds of spark advance characteristics.