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(11) | EP 0 035 859 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Ship maneuvering gear |
| (57) Ship maneuvering gear for a ship having two 360°- turning propellers disposed symmetrically
relative to the ship's central bow-stern line, has a rotatable hand lever (HL) and
an arithmetic circuit (MC) which responds to the rotation of the hand lever. When
the hand lever (HL) is rotated by an angle relative to the ship's bow-stern direction,
the output from the arithmetic circuit (MC) controls the orientations of the two propellers
so that the composite propulsive power of the two propellers causes the ship to move
in a lateral or obliquely lateral direction without causing any turn of the ship,
which direction is in agreement with said angle of rotation of the hand lever. |
[0001] This invention relates to a ship maneuvering gear, and more particularly to a maneuvering gear of a ship having two or more propulsion units whose thrusts can be turned to any direction at will, which propulsion units are for instance rotating-blade propellers (e.g., Voith-Schneider propellers) or Z-type propellers turnable about vertical axes perpendicular to propeller shafts thereof.
[0002] Two maneuvering gears have been used heretofore to control two propellers. However, it has been proposed recently to use one maneuvering gear with one lever or handle to maneuver the two propellers so as to facilitate easy maneuver (for instance, Japanese Patent Publication No. 47,234/1976).
[0003] In a previously proposed one-lever maneuvering gear, the ship can be controlled by the one maneuvering lever so as to move ahead or astern, to turn, or to stop, but the proposed one-lever maneuvering gear does not allow lateral movement or obliquely lateral movement of the ship. What is meant by the lateral or obliquely lateral movement of a ship is a movement of the ship in the lateral or obliquely lateral direction without any turning of the ship.
[0004] More specifically, propulsion units are generally mounted on a ship astern of the center of turning thereof (the center of turning of a ship is generally located close to the midpoint of the ship length in most types of ship). In a ship with the propulsion units mounted astern, the obliquely lateral movement ahead is impossible, although the obliquely lateral movement astern is possible to a certain extent. A maneuvering gear of the prior art for the ship with the propulsion units mounted astern has shortcomings in that the direction of the ship's lateral movement astern does not coincide with the direction of the maneuvering lever, and that the lateral movement of the ship is impossible.
[0005] Sometimes, propulsion units are mounted close to the bow of a ship, and the ship's center of turning comes astern the propulsion units in this case. A maneuvering gear of the prior art for a ship with the propulsion units mounted close to the bow thereof has shortcomings in that the obliquely lateral movement astern is impossible, although the obliquely lateral movement ahead is possible to a certain extent, that the direction of the ship's lateral movement ahead does not coincide with the direction of the maneuvering lever, and that the lateral movement of the ship is impossible.
[0006] Therefore, an object of the present invention is to obviate the abovementioned shortcomings of the prior art, by providing an improved ship maneuvering gear to facilitate lateral movement and obliquely lateral movement of a ship through manual operation of one hand lever.
[0007] Another object of the invention is to provide a ship maneuvering gear in which the manually set direction of the hand lever coincides with the direction of the actual lateral or obliquely lateral movement of the ship.
[0008] Thus, the ship maneuvering gear of the invention ensures easy and accurate maneuver of a ship.
[0009] To fulfil the aforesaid objects, in a ship having a port propeller of 360°-turning type and a starboard propeller of 360°-turning type disposed symmetrically relative to a ship's central bow-stern line through a ship's center of turning, a preferred embodiment of the ship maneuvering gear according to the present invention controls the orientations of the two propellers by regulating the orientations of one maneuvering lever so that the two propellers produce a composite propulsive force acting on the ship's center of turning in a lateral or obliquely lateral direction, which direction coincides with the orientation of the maneuvering lever. More specifically, when the maneuvering lever is turned by an angle 6 relative to the ship's bow-stern direction, one of the two propellers is turned about a center of turning thereof by an angle 90°+6-y relative to the ship's bow-stern direction while the other one of the two propellers is turned about a center of turning thereof by an angle 90°-6-y relative to the ship's bow-stern direction, y being an angle between the ship's central bow-stern line and a line from the ship's center of turning to the propeller's center of turning.
[0010] The aforesaid 360°-turning propellers can be replaced with rotating-blade propellers (e.g., Voith-Schneider propellers). When two rotating-blade propellers are used, if the maneuvering lever is turned by an angle 6 as described above, the rotating blades of the two propellers are so controlled as to produce thrust with the aforesaid orientations 90°+6-y and 90°-θ-y respectively.
[0011] For a better understanding of the invention, reference is made to the accompanying drawings, in which:
Fig. 1A is a schematic vertical sectional view of a ship maneuvering gear according to the present invention;
Fig. 1B is an explanatory diagram showing the arrangement of a worm gearing means in the maneuvering gear of Fig. 1A;
Fig. 2 is a schematic partial plan view of a ship, showing the disposition of two propellers mounted thereon;
Fig. 3 is a partially cutaway perspective view of an operating board of the maneuvering gear of the invention;
Fig. 4 is an explanatory diagram showing the range in which a hand lever is moved;
Fig. 5 is a block diagram of the electric circuit of the ship maneuvering gear of the invention;
Fig. 6 shows a maneuvering schedule of two propellers by the ship maneuvering gear of the invention;
Fig. 7 is a diagram illustrating the operating principles of a ship maneuvering gear of the invention under typical operating conditions;
Figs. 8 through 10 are diagrams similar to Fig. 7, showing the operations under different operating conditions;
Fig. 11 is a diagram similar to Fig. 7 for a ship having propulsion units mounted ahead of the ship's center of turning; and
Figs. 12 and 13 are block diagrams of two examples of the arithmetic circuit and the servo amplifier.
[0012] Throughout different views of the drawings, 1 is a prime mover, 2 is a horizontal intermediate shaft, 3 is an upper bevel gear, 4 is a vertical intermediate shaft, 5 is a lower bevel gear, 6 is a propeller shaft, 7p, 7s are propellers, 8 , 8s are hydraulic motors, 9 is a worm s gear shaft, 10 is a vertical turning shaft, 11 is an operating board, HL is a hand lever, PX, Py are synchro motors or potentiometers, SR is a slip ring, MC is an arithmetic circuit, A-P, A-S are servo amplifiers, Fp, F are feedback s detector means, Tp, T are synchro transmitters, R , Rs are registers, S/A is a synchro analog converter, COMP is a phase comparator, AD is an adder, DS is a differential synchronizer, SYR is a synchronous rectifier, CH is a changeover switch, 0 is a ship's center of turning, A, B are propeller's centers of turning, X is a ship's central bow-stern line, θ is a rotating angle of the hand lever HL, and y is an offset angle of the propeller's centers of turning A and B.
[0013] Fig. 1 through Fig. 5 illustrates an embodiment of the ship maneuvering gear according to the present invention as applied to a ship with two 360°turning propulsion (Z-type propulsion) units.
[0014] Figs. 1A, 1B, and 2 show the mechanism of a 360°-turning propulsion unit. Output power from a prime mover 1 is transmitted to a port or starboard propeller 7p or 7s through a horizontal intermediate shaft 2, an upper bevel gear 3, a vertical intermediate shaft 4, a lower bevel gear 5, and a propeller shaft 6. A hydraulic motor 8 p or 8 s is connected to a worm shaft 9, so as to turn the propeller 7 or 7s about the axis of a vertical turning shaft 10 by the movement of the worm shaft 9 activated by the hydraulic motor 8P or 8 . p s
[0015] Figs. 3 through 5 show the structure and formation of the ship maneuvering gear of the invention. Referring to Fig. 3, an operating board 11 of the maneuvering gear has a hand lever 11. As shown in Fig. 4, the hand lever HL is a maneuvering lever which can be inclined relative to a vertical center line (coinciding with the Z-axis of Fig. 4) up to a certain predetermined angle (up to 35° in the illustrated embodiment) and can be freely rotated about the center line within a circle h defined by a 360° rotation of the upper end of the hand lever HL with 35° inclination. PX and Py are synchro motors (having a trademark of SELSYN motor) or potentiometers to detect the rotation and inclination of the hand lever HL, and the outputs thereof are applied to an arithmetic circuit MC so as to produce signals to actuate the hydraulic motors 8p and 8s through servo amplifiers A-P and A-S. The hydraulic motors 8p and 8s turn the propellers 7p and 7s respectively, while feedback potentiometers F p and Fs compares the actual orientations of the propellers 7 p and 7 s against set values determined by the arithmetic circuit MC. Synchro transmitters Tp and T s transmit signals representing the actual orientations of the propellers 7p and 7s to the operating board 11, and registers Rp and Rs including servo receiving indicated the actual orientations of the propellers 7p and 7s in response to the signals from the synchro transmitters Tp and T s respectively.
[0016] The synchro motor or potentiometer Px to detect the rotation of the hand lever HL may be disposed above or below the slip ring SR of Fig. 3 in tandem therewith, which slip ring SR is disposed along the vertical central axis Z of Figs. 3 and 4.
[0017] During regular cruising of a ship having the maneuvering gear of the aforesaid formation according to the present invention, the direction of propulsion acting on the ship is set by the rotating angle of the hand lever HL while the magnitude of the propulsive power or the ship speed is controlled by regulating the inclination of the hand lever HL.
[0018] Figs. 12 and 13 show two examples of the arithmetic circuit MC and the servo amplifiers A-P and A-S, in which examples the detecting means Px and Py are assumed to be synchro motors whose outputs are applied to the arithmetic circuit MC so as to produce signals applicable to the hydraulic motors 8p and 8s through the servo amplifiers A-P and A-S.
[0019] In the example of Fig. 12, the two output signals from the synchro motors Px and Py are applied to synchro analog converters S/A of the arithmetic circuit MC for analog conversion. Outputs from the synchro analog converters S/A are applied to and processed by an adder AD, and the output from the adder AD is amplified by an amplifier AMP. The amplified signal from this amplifier AMP is applied to feedback adders FAD to which signals from the feedback detector means Fp and Fs for the propellers 7p and 7s are also applied, so as to effect arithmetic operations necessary for the desired feedback control. The feedback detector means Fp and F of this example can be potentiometers.
[0020] The output signals from the feedback adders FAD are amplified by amplifying circuits AMP of the servo amplifiers A-P and A-S. In the servo amplifiers A-P and A-S of this example, phase comparators COMP receive the amplified signals from the amplifying circuits AMP thereof and compare the received signals against a reference so as to separate clockwise instruction signals from counterclockwise instruction signals. Each servo amplifier A-P or A-S is connected to two magnetic valves MV, so that the corre- sponding hydraulic motor 8 p or 8 s is selectively driven either clockwise or counterclockwise.
[0021] In the example of Fig. 13, the signal from each of the synchro motors Px and Py is applied to both of the two differential synchronizers DS of the arithmetic circuit MC respectively. The differential synchronizers DS of this example also receives signals from the feedback synchro motors Fp and Fs for the propellers 7p and 7s, so as to effect the arithmetic operations necessary for the desired feedback control. The output signals from the arithmetic circuit MC are applied to the servo amplifiers A-P and A-S, where synchronous rectifiers SYR separate clockwise instruction signals from counterclockwise instruction signals based on the nature of the output signals from the arithmetic circuit MC, e.g., potentials thereof, and the thus separated instruction signals are amplified by amplifier circuits AMP provided for each of the clockwise and counterclockwise instruction signals. Each servo amplifier A-P or A-S is connected to the corresponding hydraulic motor 8 p or 8 s through two magnetic valves MV, as in the case of the example of Fig. 12.
[0022] As noted above, the example of Fig. 13 uses feedback synchro motors Fp and F instead of the feedback potentiometers of the example of Fig. 12.
[0023] When either one or both of the detecting means Px and Py are potentiometer, only the example of Fig. 12 can be used, and the operations of the maneuvering gear with such detecting potentiometers are similar to those with the detecting synchro motors as described in the foregoing, except that the synchro analog converters S/A can be dispensed with in the case of the detecting potentiometers.
[0024] The foregoing descriptions of the examples of Figs. 12 and 13 refer to the control mode for regular cruising of the ship. To provide an additional control mode for the lateral or obliquely lateral movement of the ship, the following modifications are necessary; namely, in the example of Fig. 12, a changeover switch and another circuit to carry out the arithmetic operations for the aforesaid additional control mode to be described hereinafter are connected to the adder AD of the arithmetic circuit MC; in the example of Fig. 13, a changeover switch and another circuit to carry out the arithmetic operations for the aforesaid additional control mode to be described hereinafter are connected to the differential synchronizers DS of the arithmetic circuit MC. The changeover switches are connected in such a manner that either of the aforesaid two control modes, one for regular cruising and one for lateral or obliquely lateral movement, can be easily selected by operating the changeover switch.
[0025] Fig. 6 shows a maneuvering schedule during regular cruising for the maneuvering gear of the invention in terms of the relationship among the positions of the hand lever HL, orientations of the propellers 7 s and 7 p as indicated by the registers 8 s and 8 p (arrows in Fig. 6), and the moving direction of the ship (arrows in Fig. 6). For instance, Operation No. 1 shows that the hand lever HL is held upright with its top H' at the neutral position to keep the ship at rest. Operations No. 2 and No. 3 show that the ship moves ahead at full and middle speed and that the orientations of the propellers vary with the ship speed even when the ship moves straightly ahead. Operations No. 4 and No. 5 show that the ship moves ahead while turning port and starboard and that the two propellers assume identical orientations at full speed but the two propellers assume different positions at middle speed as shown by dotted lines of Fig. 6. Similarly, the ship can be maneuvered so as to turn starboard and port about one point or to move back simply by setting the hand lever HL accordingly as shown in Fig. 6.
[0026] As described in the foregoing, in the ship maneuvering gear of the invention, the hand lever HL can be rotated and inclined to any position in the 360° range, so that the ship can be maneuvered to move not only ahead and back but also sideways, and the composite propulsive power of the two propellers 7 P and 7s can be varied from zero to the maximum by controlling the inclination of the hand lever HL while maintaining the constant propulsive powers at the individual propellers. Accordingly, the ship speed can be controlled from stop as instructed by the upright or neutral position of the hand lever HL to the full speed as instructed by the maximum inclination of the hand lever HL.
[0027] In a preferred embodiment of the invention, functions of lateral movement and obliquely lateral movement of a ship are included by providing a program to effect such movements in the arithmetic circuit MC of Fig. 5. As shown in Fig. 3, a changeover switch CH is mounted on the operating board 11, and the arithmetic circuit MC is switched between the maneuver for regular cruising as described in the foregoing by referring to Figs. 3 through 5 and the maneuver for the lateral or obliquely lateral movements.
[0028] The principles for effecting the lateral and obliquely lateral movements of a ship by the ship maneuvering gear of the invention will be now explained. Fig. 7 shows an embodiment for a ship having two 360°- turning propellers 7 and 7 , but the present invention is s not restricted to such propellers and any propulsion units whose thrust direction can be turned 360° such as rotating-blade propellers (e.g., Voith-Schneider propellers) can be used together with the ship maneuvering gear of the invention.
[0029] Referring to Fig. 7, the two propellers 7p and 7 can be turned 360° about their counters of turning A and B respectively. The port and starboard propellers 7p and 7s are disposed symmetrically relative to a ship's central bow-stern line X through a ship's center of turning 0, so that the propeller's centers of turning A and B are disposed on the port side and starboard side astern of the ship's center of turning 0 and the distance between the centers 0 and A is the same with the distance between the centers 0 and B. When the hand lever HL is turned to a position having an angle 6 relative to the ship's bow-stern direction parallel to the ship's central bow-stern line X, one of the two propellers is turned to a position where thrust thereof has an angle 90°+θ-y relative to the ship's bow-stern direction while the other one of the two propellers is turned to a position where thrust thereof has an angle 90°-θ-y relative to the ship's bow-stern direction, y being an angle between the ship's central bow-stern line X and a line from the ship's center of turning 0 to the propeller's center of turning A or B, whereby the ship is-propelled into an obliquely lateral direction with an angle θ relative to the ship's central bow-stern line X.
[0030] The reasons for using the aforesaid relationship among the orientations of the hand lever HL and the propellers 7p, 7s will now be described.
[0031] In Fig. 7, the ship's center of turning 0 is generally located on the ship's central bow-stern line X near the midpoint of the ship, and the propeller's centers of turning A and B of this embodiment are located astern of the ship's center of turning 0. Xp and Xs represent axes through the propeller's centers of turning A and B in parallel to the ship's central bow-stern line X.
[0032] When the hand lever HL is pushed down ahead by a maximum extent of 35° and turned by an angle 6 relative to the ship's bow-stern direction as shown in Fig. 7, if the changeover switch CH assumes the position for regular cruising maneuver, the propellers 7p and 7s are turned by the angle 6 from positions lp and 1s aligned with the axes Xp and Xs to positions 3p and 3s so as to cause the ship to turn starboard. In the figure, arrows for the propellers represent the orientations of the propellers, and the directions of the propulsive forces generated in the propellers are opposite in sense to those of the arrows for the propellers. If the changeover switch CH is switched to the position for the lateral or obliquely lateral movement, the port propeller 7p is slightly turned rightward from the position lp to a position 2p while the starboard propeller 7s is noticeably turned leftward (upward) from the position 1 to a position 2s. To fulfil the obliquely laterally movement of the ship in the direction set by the hand lever HL, the positions 2 p and 2s must be defined accurately.
[0033] Still referring to Fig. 7, a circle with a center at the ship's center of turning 0 (to be referred to as the "circle 0", hereinafter) is drawn so that the extensions of the arrows representing the orientations of the propellers 7p and 7s at the positions 2p and 2s have tangents to the circle 0 at points of contact M and N. If such tangents from the points A and B representing the propeller's centers of turning to the aforesaid circle 0 intersect at a point C, the following relationship is satisfied in the triangle CAB.
here, x ≡ <ACB
α ≡ <CAB
β ≡ <csa.
[0036] The line sections AM and BN are tangents to the circle 0 and the triangle OAB is an isosceles triangle, so that OA=OB, OM=ON, and <OMA=<ONB=90°, so that ΔOMA≡ΔONB. Accordingly, y=6, and the equation (3) can be rewritten as
[0038] Comparing the equations (4) and (2), x=2y and <ACB=<AOB, so that the point C is on a circle through the three points 0, A, and B.
[0039] If a composite thrust of the thrusts of the two propellers at the positions 2p and 2s in the directions of the tangents of the circles 0 from the points A and B is determined at the point C, the thrust Tp of the port propeller 7p at the position 2 p and thrust T s of the starboard propeller 7s at the position 2 produce a composite thrust T whose direction coincides with that of the line segment CO from the point C to the ship's center of turning 0.
[0040] Thus, when the hand lever HL is turned and set at the direction of the line segment CO, the direction of the composite thrust T of the thrusts Tp and Ts of the two propellers 7p and 7s coincides with the thus set direction of the hand lever HL.
[0041] Based on the principles described above, the positions 2 p and 2 s to be assumed by the propellers 7p and 7s in response to the set position of the hand lever HL can be expressed in the following manner.
[0042] When the hand lever HL is turned rightward by an angle θ, <6=COX=<COA+<AOX and <COA=<CBA=β while <AOX=y, so that θ=β+y. Accordingly,
[0044] In view of the equation (5) and the relationship of x=2y, the equation (6) can be rewritten as
[0045] Considering the equation (7), the angle p between the axis Xp and the line section AC is given as follows.
[0046] What is meant by the equation (8) is that the position 2p is reached by turning the propeller 7p counterclockwise from the axis X (direction of straight ahead) by an angle µ.
[0047] Similarly, the position 2s is reached by turning the propeller 7s clockwise from the axis X (direction of straight forward) by an angle w given by
[0048] The validity of the aforesaid principles under other ship maneuvering conditions will be now described.
[0049] Fig. 8 shows a diagram illustrating angular relationship among the hand lever HL and the two propellers 7p and 7s for the cases of θ=90° and θ=0°. When the hand s lever HL is turned so as to set θ=90°, the angle of orientation p for the port propeller 7p is given by the equation (8) as follows:
so that the port propeller 7p is turned clockwise by an angle y.
[0050] The angle of orientation w for the starboard propeller 7s under the condition of θ=90° is given by the equation (9) as follows:
so that the starboard propeller 7s is turned clockwise by an angle 180°-y.
[0051] In this case, the thrusts T p and Ts of the propellers 7p and 7 s are aligned with the lines OA and OB passing the ship's center of turning 0. Accordingly, the composite thrust T of the two thrusts Tp and Ts in this case is exactly lateral to the ship's central bow-stern line X at the ship's center of turning 0, whereby the ship is propelled exactly laterally.
[0052] The next case is for θ=0° actuated by pushing the hand lever HL down straightly ahead. The equation (8) gives the angle of orientation at the position 2p for the port propeller 7p as µ=90°-(θ+y)=90°-y, while the equation (9) gives the angle of orientation at the position 2s for the starboard propeller 7s as ω=90°+θ-y=90°-y. Accordingly, the composite thrust of the thrusts generated by the two propellers 7p and 7s in this case causes the ship to move straight ahead.
[0053] Fig. 9 shows the case in which the angle 6 set by the hand lever HL is larger than 90°. In the figure, the orientation of the port propeller 7p at the position 2 is shown as 90°-a taken in the clockwise direction from the position 1 , and the equation (7) gives α=180°-θ-y, so that 90°-α=90°-180°+θ+y=-(90°-θ-y), which coincides with the value given by the equation (8) for this case. The figure also shows the orientation of the starboard propeller 7s at the position 2s as 90°+β taken in the clockwise direction from the position ls. In the triangle CAB, the angle P is given by β=180°-α-x. Since x=2y, β=180°-α-2y. Thus,
[0054] Since θ+α+y=180°, α=180°-θ-y, and substitution of this a in the equation (10) gives
which coincides with the value given by the equation (9). In this case, the composite thrust T of the thrust generated by the two propellers acts on the ship's center of turning 0 in an oblique direction, so that the obliquely lateral movement of the ship is effected.
[0055] Due to the reasons described above, the inventors noted the fact that for any angle e set by the hand lever HL the orientation of the port propeller 7 is given by 90°-6-y while the orientation of the starboard propeller 7s is given by 90°+θ-y. Accordingly, the ship maneuvering gear of the invention automatically controls the orientations of the two propellers in response to the angle θ set by the hand lever HL based on the aforesaid angular relationship among the hand lever and the propellers. The control pattern for the lateral or obliquely lateral movement of the ship is different from the control pattern for regular cruising, so that a changeover means is provided to select one of the two control patterns. In the embodiment of Fig. 3, the changeover switch CH is to switch the control between the regular cruising mode and the lateral or obliquely lateral movement mode.
[0056] As regards the speed control during the lateral or obliquely lateral movement, the revolving speed of the prime mover driving the propellers can be controlled, for instance by a speed control lever provided on an operating board such as the board 11 shown in Fig. 3. It is also possible to control the revolving speed of the prime mover by the synchro motor or potentiometer Py to detect the inclination of the hand lever HL, for instance by increasing the revolving speed of the prime mover with the increase of the forward inclination of the hand lever HL. In this case, the ship speed during the lateral or obliquely lateral movement can be reduced by pulling up the hand lever HL toward the upright position thereof.
[0057] The control of the ship speed can be also fulfilled by modifying the orientations of the propellers. In this case, the manner of changing the orientations of the two propellers in response to the pulling up or pushing down of the hand lever HL for the ship speed control is similar to that in the control for the regular cruising, except the following difference. The difference in the manner of changing the propeller orientations is due to the fact that, although the ship speed reduction during the regular cruising ahead or astern or turning can be achieved by pulling up the hand lever HL which pulling up causes the propellers to turn outboard, the turning of the propellers outboard during the lateral or obliquely lateral movement under the control of the invention tends to cause the ship to turn, which turn interferes with the desired lateral or obliquely lateral movement. Accordingly, the following arrangement is necessary to control the ship speed by modifying the orientations of the propellers without causing any turning of the ship during the lateral or obliquely lateral movement thereof.
[0058] Referring to Fig. 10, to reduce the ship speed during the obliquely lateral movement of the ship in the direction of angle 6 relative to the straight ahead direction (moving ahead starboard), the two propellers are turned from positions (1) to positions (2) by 90° in response to the pulling up of the hand lever HL to the upright position thereof. More specifically, the port propeller 7p is turned counterclockwise 90° from the position (1) to the position (2), and the starboard propeller 7s is similarly turned counterclockwise 90°.
[0059] The composite thrust T2 of the thrusts of the two propellers at the positions (2) of Fig. 10 is directed obliquely lateral through the ship's center of turning 0, so that the resultant propulsive force tends to cause the ship to move ahead port so as to brake the movement in the direction of ahead starboard.
[0060] If a stronger brake action than the aforesaid oblique propulsive force is desired, the hand lever HL is further pulled away from the upright position to the position (3) which can be reached by turning the hand lever HL 180° from the initial position (1) for the lateral movement in the ahead starboard direction, as shown in the top portion of Fig. 10. Whereby, the two propellers are turned from the positions (1) by 180° until reaching positions (3) through the aforesaid positions (2). At the positions (3), the two propellers produce a composite thrust T3' which acts to pull back the ship in a direction 180° away from or just opposite to the direction of the ahead starboard movement.
[0061] In the foregoing description, the propellers are assumed to be mounted on the ship astern of the ship's center of turning 0. It should be noted that the maneuvering gear of the invention can be also used with propellers mounted ahead of the ship's center of turning 0.
[0062] Fig. 11 shows a case in which the propellers are mounted on the bow side of a ship relative to the ship's center of turning 0. In this case, when the hand lever HL is turned by an angle θ, the port propeller 7p is turned by an angle 90°-a relative to the direction of the axis X , while the starboard propeller 7s is turned counters clockwise by an angle 90°-β relative to the axial direction X .
[0065] The aforesaid equations for 90°-a and 90°-β are identical with the equations (9) and (8) except that the applicable propellers are interchanged between the port and starboard sides.
[0066] Thus, it is shown that the ship maneuvering gear can be applied to a ship having two propellers mounted ahead of the center of turning 0 thereof.
[0067] Although the embodiments described hereinbefore use the Z-type propellers, the rotating-blade propellers such as the Voith-Schneider propellers can be used instead of the Z-type propellers. More particularly, the object of the present invention can be fulfilled by turning the direction of the thrust of the rotating-blade propellers in lieu of the turning of the Z-type propellers in the embodiments described in the foregoing.
[0068] As described in the foregoing, the ship maneuvering gear of the invention facilitates lateral or obliquely lateral movement of a ship simply by regulating one hand lever, while keeping the direction of the lateral or obliquely lateral movement in agreement with the orientation of the hand lever. Thus, the present invention has an outstanding effect of providing easy and accurate maneuver of lateral or obliquely lateral movement of a ship which has been difficult to maneuver heretofore.
[0069] Although the invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in details of construction and the combination and arrangement of parts may be resorted to without departing from the scope of the invention as hereinafter claimed.
1. A maneuvering gear of a ship having a port propulsion unit and a starboard propulsion
unit disposed symmetrically relative to a ship's central bow-stern line through a
ship's center of turning, thrust direction of each of said propulsion units being
turnable 360° about a propulsion unit's center of turning, said maneuvering gear comprising
a hand lever that can be rotated 360°, an arithmetic circuit responding to the rotating
angle of said hand lever, and an actuating means responding to output of said arithmetic
circuit in such a manner that, when the angle of said hand lever relative to ship's
bow-stern direction is θ, the actuating means turns one of said propulsion units so
as to make the angle of thrust thereof relative to the ship's bow-stern direction
90°+6-y while turning the other one of said propulsion units so as to make the angle
of thrust thereof relative to the ship's bow-stern direction 90°-0-y, y being an angle
between the ship's central bow-stern line and a line from the ship's center of turning
to the propulsion unit's center of turning.
2. A maneuvering gear as set forth in claim 1, wherein said propulsion units are two
360°-turning propellers each of which can be turned about a vertical axis perpendicular
to a propeller shaft thereof, and said propulsion unit's center of turning is said
vertical axis of the 360°-turning propeller.
3. A maneuvering gear as set forth in claim 1, wherein said propulsion units are two
rotating-blade propellers.
4. A maneuvering gear as set forth in claim 1, wherein said maneuvering gear includes
a synchro motor responding to the rotating angle of the hand lever so as to inform
the arithmetic circuit of the rotating angle of the hand lever.
5. A maneuvering gear as set forth in claim 1, wherein said maneuvering gear includes
a potentiometer responding to the rotating angle of the hand lever so as to inform
the arithmetic circuit of the rotating angle of the hand lever.
6. A maneuvering gear as set forth in claim 1, wherein said actuating means includes
two hydraulic motors coupled to said propulsion units through worm gearing means.
7. A maneuvering gear as set forth in claim 1, wherein said maneuvering gear includes
synchro transmitters producing signals representing orientations of the thrusts of
the two propellers and registers having synchro receivers to receive said signals
from the synchro transmitters so as to indicate the orientations of the thrusts.
8. A maneuvering gear as set forth in claim 1, wherein said maneuvering gear includes
feedback detector means to detect orientations of said thrusts of the propulsion units
so as to produce signals showing the detected orientations and servo amplifier means
to receive signals from said arithmetic circuit so as to deliver amplified signals
to said actuating means; said arithmetic circuit includes two synchro analog converters
to convert signals representing the rotating angle and inclination of said hand lever,
an adder to add converted signals from said synchro analog converters, and feedback
adders to receive signals both from said adder and from said feedback detector means
so as to produce output signals of the arithmetic circuit; and said servo amplifier
means includes amplifier circuits to amplify signals from said arithmetic circuit
and comparator to differentiate clockwise instruction signals to said propulsion units
from counterclockwise instruction signals thereto by comparing signals from said amplifier
circuits against a reference.
9. A maneuvering gear as set forth in claim 1, wherein said maneuvering gear includes
feedback detector means to detect orientations of said thrusts of the propulsion units
so as to produce signals showing the detected orientations and servo amplifier means
to receive signals from said arithmetic circuit so as to deliver amplified signals
to said actuating means; said arithmetic circuit includes differential synchronizer
means to receive signals both from said hand lever and from said feedback detector
means so as to produce output signals of the arithmetic circuit; and said servo amplifier
means includes synchronous rectifier means to differentiate clockwise instruction
signals to said propulsion units from counterclockwise instruction signals thereto
depending on nature of said output signals from the arithmetic circuit and amplifier
circuits to amplify the thus differentiated signals from said synchronous rectifier
means.
10. A maneuvering gear as set forth in any one of claims 8 and 9, wherein said feedback
detector means are synchro motors coupled to said propulsion units.
11. A maneuvering gear as set forth in any one of claims 8 and 9, wherein said feedback
detector means are potentiometers coupled to said propulsion units.
12. A maneuvering gear as set forth in claim 1, wherein said maneuvering gear includes
potentiometers coupled to said hand lever so as to detect the rotation and inclination
of said hand lever, and feedback potentiometers to detect orientations of said thrusts
of the propulsion units so as to give signals showing the detected orientations, and
servo amplifier means to receive signals from said arithmetic circuit so as to deliver
amplified signals to said actuating means; said arithmetic circuit includes an adder
to add signals from said potentiometer coupled to said hand lever, and feedback adders
to receive signals both from said adder and from said feedback potentiometers so as
to produce output signals of the arithmetic circuit; and said servo amplifier means
includes amplifier circuits to amplify signals from said arithmetic circuit and comparator
means to differentiate clockwise instruction signals to said propulsion units from
counterclockwise instruction signals thereto by comparing signals from said amplifier
circuits against a reference.