US 5,700,170 A · Variable diameter jet propulsion unit

Abstract

An apparatus is disclosed to alter the diameter of the nozzle of a jet boat, thereby allowing a user to maximize acceleration, top speed, fuel economy or other factors. The disclosed apparatus allows a user to adjust the nozzle diameter opening, while the boat is moving, by an elastic annular hydraulic bladder that reduces the cross sectional area of a cone formed by a plurality of cone plates. The apparatus is compatible with steering and trim adjustment devices, and is located rearward of them. The apparatus is also compatible with existing jet boat, and provides a bowl adapter that may be attached to the impeller bowl of an existing jet. A steering collar attaches to the bowl adapter by two vertical pins to allow rotation to the left and right. Two horizontal pins on the steering collar support a nozzle front lock plate in a manner that allows vertical trim adjustment. The nozzle cone plates are mounted in a hinged manner to the nozzle front lock plate and the nozzle housing support. A splines assembly forces the nozzle cone plates to act in a symmetrical manner, and bridges the gaps between adjacent nozzle cone plates when the nozzle is open, thereby preventing the bladder from entering the gaps. An elastic block biases the nozzle cone plates radially outwardly, and opens the nozzle when the hydraulic bladder is not engaged.

Claims19

Dependent claims

A variable diameter jet propulsion unit for a marine craft, comprising:

(a) a nozzle housing, defining an annular bladder recess;
(b) at least three nozzle cone plates, pivotally mounted within the nozzle housing;
(c) an annular bladder, carrried by the bladder recess and in contact with the nozzle cone plates;
and
(d) a source of hydraulic power, attached to the annular bladder.

2 more elements

Dependencies are inferred from the claim text.

Variable diameter jet propulsion unit

Life of this patent

Variable diameter jet propulsion unit

Life of this patent

Abstract

Claims19