Propeller pitch controlling arrangement having a fuel economizing feature

Claim 1

A propeller pitch controlling arrangement having a fuel economizer feature for use on marine vessels having an engine fuel rack and a variable pitch propeller, said propeller pitch controlling arrangement comprising: (a) a pitch controlling servomechanism operably engaged to the variable pitch propeller such that the pitch of the variable pitch propeller is controlled as a function of the amount of fluid pressure delivered thereto; (b) a fluid steering valve connected to said pitch controlling servomechanism and operable to one of a first and second valve position wherein fluid pressure from one of associated respective first and second flow paths is directed to said pitch controlling servomechanism; (c) said fluid steering valve having respective first and second pilot operated portions which, when actuated by respective first and second pilot signals, effect movement to such first and second valve positions, such first and second valve positions being mutually exclusive in operation; (d) a relay valve receptive of fluid pressure having a value determined by the marine vessel speed, said relay valve being connected to said first pilot portion of said fluid steering valve such that, upon reduction of such speed determined fluid pressure below a preselected value, such first pilot signal is transmitted to said fluid steering valve and said first flow path is established thereby; (e) a pitch control valve manually operable over a range of fluid pressure delivery settings such that, when said first flow path is established, a first operating fluid pressure is transmitted thereover to said pitch controlling servomechanism; (f) a mode selector valve manually operable to an economizer position and spring returnable to a normal position, such operation to the economizer position effecting a pulse-type transmission of such second pilot signal to said second pilot portion of said fluid steering valve such that said second flow path is established thereby; (g) economizer valve means mechanically linked to such marine vessel engine fuel rack for transmitting a second operating fluid pressure to said pitch controlling servomechanism when said second flow path is established, such second operating fluid pressure being in inverse proportion to movement of such marine vessel engine fuel rack; and (h) such first pilot signal being continuous in duration when such speed determined fluid pressure has been reduced below such preselected value, such first pilot signal thereby overriding such pulse-type second pilot signal in the event such first and second pilot signal occur simultaneously.