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. 15, 1990
Filed:
Apr. 12, 1989
Dragerwerk AG, Lubeck, DE;
Abstract
A piston and cylinder unit provides a supply actuable by means of an actuation device for delivering respiratory air in a respiratory cycle of a respirator. Its piston is sealed with its cylinder by means of a pair of rolling membranes arranged symmetrically with regard to one another. The membranes separate the cylinder contents into an antechamber and a working chamber. The wear of the rolling membranes during the working strokes and especially during the starting is decreased by a clean rolling of the folds. Also a leakage control takes place even during operation and an immediate detection of leaks due to bending stress, aging or other influences is guaranteed. For this purpose an inner chamber which is enclosed by the two rolling membranes is under a pressure different from the pressure in the antechamber and the working chamber so that the highest pressure is on a concave inside of the folds.