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. 25, 2000
Filed:
Mar. 23, 1998
Thomas A Frank, Middletown, RI (US);
The United States of America as represented by the Secretary of the Navy, Washington, DC (US);
Abstract
A fluid propulsion device is used to discharge a working fluid at a predemined variable discharge rate. The fluid propulsion device includes a fluid chamber that is expandable upon receiving the working fluid. The fluid chamber has a plurality of chamber sections that contract at different predetermined rates to discharge the working fluid from the fluid chamber at the variable discharge rate. In one example, an elastomeric bladder defines the fluid chamber and includes a plurality of bladder sections each having a different coefficient of elasticity, causing the bladder sections to contract at the different predetermined rates. In one application, the fluid propulsion device is used in a projectile launching system, such as an airgun. The fluid propulsion system controls the launching of the projectile by discharging the working fluid at the variable discharge rate, resulting in a corresponding acceleration of the projectile.