Patent GB-1360041-A (GB)
Title: Control apparatus for a blade wheel propeller
IPC: B63H1/10
Filed: 1971-06-17
Abstract: 1360041 Controlling blade wheel propellers J M VOITH GmbH 17 June 1971 [18 June 1970] 28483/71 Heading B7G [Also in Division F2]  Control apparatus for a blade wheel propeller, the control apparatus comprising; two pilot controls for operating respective servomotors of the propeller; a first servoshaft 51 which is rotatable from a control position (on board a ship carrying the propeller); a second servoshaft 20 which is rotatable from a control position; a rectilinear motion transmission 17 coupled to the first and second servoshafts and having middle element 34 with a main pivot axis 30 thereon, the rectilinear motion transmission 'being arranged such that when one servoshaft is kept stationary and the other is rotated, the main pivot axis follows a substantially straight path or an approximately straight path; and pivotal connection means connecting each pilot control to said middle element 34 at said main pivot axis. A correction transmission 70 may optionally be interposed between the first servoshaft 81 and the rectilinear motion transmission so that, in use, the speed of a ship in which a propeller is fixed is lowered with  increased helm angle. The transmissions 17, 70 are supported by the shafts 20, 81 and two pivots 84, 85 which are mounted at a fixed location on a cover 18, Figs. 5, 6, of the propeller. The pilot controls are in the form of valves 14, 15 controlling respective servomotors 12, 13 so that the servomotors cause the top of a control stick of the propeller (not shown) to undergo the same motion as the main pivot axis 30. Pivoting of shaft 81, in response to a speed control at a control position, causes pivoting of a rod 71 fixed to shaft 81, and pivoting of a first rocker lever 73 about a pivot 80 at one end of a second rod 72 the other end of which (Fig. 6) is pivoted at 86 to a second rocker lever 74. The first rocker lever causes translational movement of a coupling 75 and hence the middle transmission element 34 including the main pivot axis 30, with outer transmission member 32 pivoting about pivot 84 and outer transmission member 33 pivoting about a pivot 37 fixed to a radius arm 35, in turn fixed to the second shaft 20 which is connected to a speed control at a control position. Movement of the pivot 30 causes movement of links 40, 50, which movement causes linkages and pivots 4 to 45 and 51 to 55 to move respective control valves 14, 15 of the servomotors. Each group of linkages and pivots 40 to 45 and 50 to 55 comprises a pivotal connection means. When a link 50 is moved, an upper lever 51 pivots about the end 61 of a rocker 54 pivoted to a fixed mount 59 to displace a pivot 53 connecting upper lever 51 to lower lever 52 (Fig. 5). Lever 52 then pivots about its end mounted on the head 65 of a piston 63 of a servomotor 13 to cause movement of a double link 55 to control the piston 57 of valve 15. The piston head 65 moves until rod 51 is superimposed on rod 52 whereupon the valve 15 closes to stop the head 65.  Pivoting of the second servoshaft 20 for steering causes a radius arm 35 fixed to the shaft 20 to move the outer transmission member 33 so as to move the main pivot axis 30 transversely of movement caused by pivoting the first servoshaft 81. There is also introduced into this movement of the main pivot axis 30 (by way of the correction transmission 70) a component of motion parallel to that caused by the first servoshaft 81, which component reduces speed with increasing helm angle. An extension arm 82 of the radius arm 35 is coupled to the second rocker lever 74 by a rod 76 which pivots the second rocker lever 74 clockwise about pivot 85 whichever way the shaft 20, rotates. The rod 71 is fixed when the first servoshaft 81 does not rotate, so that rotation of the second rocker lever is then transmitted via rod 72 to the first rocker lever 73 which causes movement of coupling 75 and hence of pivot 30. In a further embodiment, Figs. 1 to 3 (not shown) the correction transmission is omitted and in another embodiment, Figs. 9, 10 (not shown) the cover 18 is rotatable so that the locations of the servoshafts 20, 81 and fixed pivots 84, 85 are variable with respect to the transmission, and hence the direction of thrust of the propeller may be aligned with the ship's axis by rotation of the cover. In a final embodiment, Figs. 11 to 13 (not shown) the main pivot axis (30) is formed as a hollow cylinder (130). The links (40, 50) are dispensed with; instead the ends of the upper levers (41, 51) are formed as rings round the hollow cylinder (130), as is a connection from the correction transmission (170) to the hollow cylinder (130). Also, whereas the cylinders of the servomotors moved in fixed housings in the embodiments described with reference to Figs. 1 to 10, the housings move on fixed cylinders and a modified correction transmission includes a cam follower.