Arrangement in connection with a swingable turn-up onboard/outboard stern aggregate for a craft
This application is a continuation of application No. 07/965,399, filed Dec. 18, 1992, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an arrangement in connection with a swingable turn-up inboard/outboard stern aggregate for craft with an inboard engine and an outboard drive unit comprising a screw, and of a kind as stated in the preamble of the following independent claim 1. 
     BACKGROUND OF THE INVENTION 
     Such a stern aggregate is known from the applicant&#39;s previous NO-PS No. 158 335, the object of which was to reduce dimensions, especially the transversal dimension, of the lower portion of the housing surrounding the propel shaft and screw shaft with bearings by using universal Joints between the propel shaft and the screw shaft. 
     In such a stern aggregate reversal of the direction of screw rotation may either be achieved by the aid of a gearbox in said inboard engine or, if desired, in the transmission from the latter to the stern aggregate. 
     The last mentioned concept will require space between the engine and the stern of the craft and it will also form an independent unit which has to be mounted, i.e. inserted between the stern aggregate and the engine. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a stern aggregate where such a gear or reversing means is part of the stern aggregate proper, so that such space as mentioned is saved, and labour for mounting is saved, since only the stern aggregate proper is to be mounted on the craft and connected with the engine. 
     According to the present invention the above object is achieved by the features recited the following independent claim 1, as well as in the following dependent claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention will be disclosed in more detail below with reference to the drawings, in which 
     FIG. 1 is a side view and partly a sectional view of the stern aggregate, mounted on the stern of a craft; 
     FIG. 2 is a diagrammatical top view of a stern aggregate with a pressure cylinder for lateral displacement of the stern aggregate for steering the craft and with pressure cylinders for turning the stern aggregate up and down into the water. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 shows an inboard/outboard stern aggregate 1 the fastening means 1a of which is mounted on the stern of craft 10, and a driving unit 2 which is swingably fastened to fastening means 1a, via a horizontal transversal axis F (FIG. 2) and an approximately vertical axis E, for lifting, and lowering, respectively, of driving unit 2 and for swinging driving unit 2 to steer craft 10 in motion. In fastening means 1a an inboard driving shaft 3 is mounted for connection with output shaft 3a, via a flange coupling 3b. Via a double universal joint A driving shaft 3 is connected with a transmission shaft 6 which is divided into two sections 6a, 6b. The first section 6a is mounted at the upper end (8) of housing 7 and connected with said universal joint A, and its second end is connected with the second section 6b of transmission shaft 6, via angular gear B. The lower end of section 6b is, via a universal joint C, preferably a double universal joint, connected with a screw shaft 4, which is mounted in the lower rear end of housing 7, with a firm angle V between screw shaft 4 and lower section 6b of transmission shaft 6, which angle V is smaller than 45°, preferably 32°, with an approximately horizontal screw shaft 4. Universal joints A and C may, e.g. be of the ball-and-socket kind which may transmit high moments of torsion relative to its moderate external dimensions. When this transmission and screw shafts 6, 4 are used at the same time, housing 7 and a lower portion of the same which forms the screw housing 7a, may be built with small transversal dimensions. The screw housing may, thus, be made narrow to reduce its resistance to water flow. 
     The drawing, however, shows that universal joints of the cardan type are used in the present case, and it is especially important to be able to use a double universal joint of the cardan type forming a transmission means C for torsional moment between lower section 6b of transmission shaft 6 and screw shaft 4 so as to reduce the bending loads on the universal joint and, thus, to reduce any vibration and loss of transmitted torsional moment to screw 5. 
     Above screw 5 a stabilizing plate 11 is provided. It is fastened to and extends rearwards from housing 7 in an approximately horizontal plane and in the waterline when the craft is in motion. 
     By the aid of pressure cylinders 9, which are fastened to fastening means 1a and housing 7, below the horizontal transverse axis F, driving unit 2 may be turned up and down and the inclined position of driving unit 2 is adjustable in order to provide the most suitable angle of attack of screw 5 in the direction of motion. In order to swing driving unit 2 about vertical axis E to steer the craft, a pressure cylinder 12 is provided as shown in FIG. 2. 
     The above mentioned reversing means for changing the direction of rotation of screw 5 as well as for cutting off the same is designated D and is arranged together with angular gear B connecting upper section 6a of transmission shaft 6 with its lower section 6b. 
     As shown in FIG. 1 angular gear B comprises two sets B1 and B2 of conical gears 11a, 11b, and 12a, 12b, with driving gears 11a, 12a being mounted to be engageable and disengageable on first/upper section 6a of transmission shaft 6 and being engaged with the driven gearwheels 11b, 12b, which are provided in a mutually non-rotatable engagement with the second section 6b. A conical intermediate gear 12c is arranged between the driving and the driven gear 12a, 12b to provide for opposite directions of rotation of section 6b when one or the other driving gear 11a, 12a is engaged, or disengaged, respectively. 
     In order to achieve said engagement and disengagement of the driving gears 11a, 12a of first section 6a clutches 13, 14 are provided in connection with respective gears 11a, 12a and are controlled from a maneuvering central 15. 
     Clutches 13, 14 are preferably air-oil actuated, the compressed fluid being supplied, via conduits 16, 17 in housing 7 to annular chambers 18, 19 in section 6a and, via bores 20, 21 in section 6a to a motor (not shown) In each clutch 13, 14. The clutches may be sliding clutches with one set of disks being fastened to section 6a and the other set being fastened to driving gears 11a, 12a, which two sets of frictional disks are made to contact each other by the aid of said pressure motor in each of the clutches 13, 14 by the aid of maneuvering central 15 which is controlled by suitable means from the driver&#39;s seat in craft 10. 
     In the embodiment as shown in FIG. 1, annular chambers 18, 19 are provided between driving gears 11a, 12a and may either consist of annular flanges, which are provided on section 6a and cooperate with an annular surface provided in housing 7, and with conduits 16, 17 opening into a respective annular chamber. The annular chamber, obviously, may consist of annular flanges extending inwards from said annular surface and being in contact with a corresponding external bearing surface on section 6a. From each of said annular chambers 18, 19 bores 20, 21 extend in section 6a to a pressure motor in each clutch 13, 14. 
     The driven gears 11a, 12a on section B are connected with each other in a manner preventing relative rotation, if desired, via splines 6c, and said gears may also be connected with section 6b, via said splines 6c to be mutually non-rotating. This is so to permit movement/elongation of section 6b, among others in case of changes of temperature, without influencing the position of gears 11b, 12b relative to the driving gears 11a, 12a, and intermediate gear 12c. 
     A gear pump 22 is provided on section 6a, suitably at the outer end of the latter, and is, via piping 23, 24 connected with the lower portion of housing 7 comprising an oil sump 25 near propeller shaft 4 and bearing 4a, and with maneuvering central 15. From the maneuvering central piping 16, 17 extends to annular chambers 18, 19 and clutches 13, 14. 
     From maneuvring central 15 a return conduit (not shown) extends to oil sump 25 for return of pressure fluid when the maneuvering central is disengaged, or via pressure valves, respectively, when the maneuvering central is engaged for forward or rearward motion of the craft, i.e. in one or the other direction of rotation of screw 5. 
     Due to the fact that reversing gear/maneuvering central 15 has been moved from craft 10 adjacent to the engine or engine shaft, to the stern aggregate and is mounted with the driving means of the latter, the total dimensions are reduced, and an independent component and mounting of the same is avoided. With this arrangement of the reversing means D between the first section 6a of transmission shaft 6 and its second section 6b, a reduced torsional moment is achieved with high rpm of the first section of transmission shaft 6 and, consequently, of the first universal joint A between first section 6a of transmission shaft 6 and the driving shafts 3, because angular gears B1, B2 are designed to be reduction gears. Second section 6b of transmission shaft 6, thus, has lower rpm and a higher moment of torsion for transmission to screw 5. The first section 6a of transmission shaft 6 with associated components may, thus, be designed with smaller dimensions, whereas the second section 6b with associatd components must be designed with larger/stronger components for transmission of said higher moment of torsion.