Self-synchronizing hydraulic control systems for marine engine transmissions

An apparatus for connecting a marine engine to a propellor shaft comprising:

• a. first transmission means for selectively allowing the engine to rotate the propellor shaft in a first direction, to rotate the propellor shaft in a second direction, or to prevent the engine from rotating the propellor shaft;
• b. a first lever;
• c. a second lever, where rotation of the second lever directs the transmission means to allow the engine to rotate the propellor shaft in a first direction, rotate of the propellor shaft in the second direction, or prevent rotation of the propellor shaft;
• and
• d. means for transmitting rotation of the first lever to the second lever comprising
• i. first casing means for containing flowable working medium,
• ii. second casing means for containing flowable working medium,
• iii. first piston means movably mounted in the first casing means for defining first and second chambers within the first casing means, volumes of the first and second chambers changing as the first piston means moves within the first casing means, where the first lever is so connected to the first piston means that rotation of the first lever displaces the first piston means within the first casing means,
• iv. second piston means movably mounted in the second casing means for defining third and fourth chambers in the second casing means, volumes of the third and fourth chambers changing as the second piston means moves within the second casing means, where the second lever is so connected to the second piston means that displacement of the second piston means within the second casing means causes rotation of the second lever,
• v. first means for allowing fluid communication between the second and third chambers,
• vi. second means for allowing fluid communication between the first and fourth chambers,
• vii. flowable working medium contained within the first through fourth chambers and the first and second fluid communication means,
• viii. reservoir means for containing additional flowable working medium;
• ix. a first port located in the first casing means, and
• x. third means for allowing fluid communication between the reservoir means and the first port, where the first port is so located in the first casing means that fluid can flow from the reservoir means into the first chamber only when the volume of the second chamber is substantially at a minimum and from the reservoir means into the second chamber only when the volume of the first chamber is
• substantially at a minimum;
• wherein movement of the first piston in a first direction causes fluid to flow from the first chamber into the fourth chamber to move the second piston in a second direction;
• and
• movement of the first piston in a third direction causes fluid to flow from the second chamber into the third chamber to move the second piston in a fourth direction.