Stern drive, in particular for twin-propeller boats

Abstract

A stern-drive unit for boats with an inclined hull, wherein the mechanical units are separated from the supporting structure, which is made in the form of a structure ( 10 ) supporting parts ( 7, 5 ) which transmit motion from an inverter ( 6 ) to the propeller, consisting a plate ( 11 ) to be attached to the keel of the boat, to which are connected a pair of V-shaped arms with a first sleeve ( 15 ) fitted at the lower ends thereof, and a third arm with a second sleeve ( 16 ) fitted at the lower end thereof, said sleeves ( 15, 16 ) housing a box ( 17 ) to which lead propeller shaft ( 5 ) and a shaft ( 7 ) orthogonal to it, leading from a motion inverter, seal means being fitted between said box ( 17 ) and said shafts ( 5, 7 ). The drive is light and easily adaptable at low cost to the various keel configurations used by different boat builders.

1 ) A drive unit for stern-drive boats, which includes a structure ( 10 ) that supports the parts ( 7 ,  5 ) which transmit motion from an inverter ( 6 ), located at engine output ( 3 ), to the propeller, consisting of a plate ( 11 ) secured to the keel of the boat, to which are attached a plurality of arms ( 12 ,  13 ,  14 ) which support means ( 15 ,  16 ) designed to house box-shaped elements ( 17 ,  18 ) into which said drive parts pass. 
   
   
       2 ) A drive unit for stern-drive boats as claimed in  claim 1 , wherein said structure ( 10 ) which supports the drive parts consists of a plate ( 11 ) to which are connected a pair of V-shaped arms, with a first sleeve ( 15 ) fitted at the lower ends thereof, and a third arm with a second sleeve ( 16 ) fitted at the lower end thereof, which said sleeves ( 15 ,  16 ) house a box ( 17 ) to which lead propeller shaft ( 5 ) and a shaft ( 7 ) orthogonal to it, leading from a motion inverter, seal means being fitted between said box ( 17 ) and said shafts ( 5 ,  7 ); 
   
   
       3 ) A drive unit for stern-drive boats as claimed in  claim 2 , wherein said V-shaped arms ( 12 ,  13 ) are located in the front part of the plate, and said third arm ( 14 ) is located at the rear, in a central position. 
   
   
       4 ) A drive unit for stern-drive boats as claimed in  claim 3 , wherein said sleeves ( 15 ,  16 ) are aligned. 
   
   
       5 ) A drive unit for stern-drive boats as claimed in  claim 4 , which includes a shell designed to enclose said box ( 17 ), which said shell consists of elements ( 19 ) designed to be fitted to said sleeves ( 15 ,  16 ) to produce a casing designed to improve the hydrodynamics of the system. 
   
   
       6 ) A drive unit for stern-drive boats as claimed in  claim 1 , which includes:
 a plate ( 11 ) attached to the keel of the boat, to which are connected a pair of V-shaped arms ( 12 ,  13 ) with a first sleeve ( 15 ) fitted at the lower ends thereof:   a third arm ( 14 ) with a second sleeve ( 16 ) fitted at the lower end thereof;   a box ( 17 ) mounted on said sleeves ( 15 ,  16 ), to which said box lead propeller shaft ( 5 ) and a shaft ( 7 ) orthogonal to it, which leads from a motion inverter;   seal means between said box ( 17 ) and said shafts ( 5 ,  7 );   
   
   
       7 ) A drive unit for stern-drive boats as claimed in  claim 6 , wherein a motion inverter unit ( 6 ) is fitted between engine shaft ( 4 ) and said drive shaft ( 7 ), which said motion inverter unit comprises a transmission with two coaxial bevel gears, fitted opposite one another on the same engine shaft, which engage a conical cogwheel mounted on said drive shaft ( 7 ), and means designed to make one or other of said bevel gears integral with said engine shaft. 
   
   
       8 ) A drive unit for stern-drive boats as claimed in  claim 7 , which includes a shell designed to enclose said box ( 17 ), which said shell consists of elements ( 19 ) designed to be fitted to said sleeves ( 15 ,  16 ) to produce a casing designed to improve the hydrodynamics of the system.