WO1991011362A1 - Directing means for water jet propulsion means for vessels and a method for directing the water jet - Google Patents

Abstract

The invention relates to a control arrangement and a method especially for controlling the direction of a water jet propulsion drive to be used in boats. A preferably electrically operated spindle motor (3) extends to a lever arm (1) controlling the direction. The function of said motor (3) depends upon the mutual centered disposition between said lever arm (1) and a control piece (5) connected to a command means (7). Said spindle motor remains non-operative when said control piece (5) remains, within a suitable clearance, in a predetermined disposition in relation to said lever arm (1), but when a predetermined deviation occurs said motor (3) strives to restore said lever arm (1) into said predetermined mutual disposition, that is into a new centered disposition corresponding to the new position of said control piece (5). According to the method the position of said lever arm (1) with respect to said control piece (5) is detected, said control piece (5) being at least partly movable in relation to said lever arm (1) and moving in accordance with the movements of said command means (7). A detected deviation of said control piece (5) from said predetermined centered disposition in relation to said lever arm (1) is tranformed into a control signal for said spindle motor (3) to restore said mutual centered disposition.

Description

Directing means for water jet propulsion means for vessels and a method for directing the water jet

The invention relates to a control arrangement especially for controlling the direction of a water jet propulsion drive to be used in boats, said arrangement comprising a lever for controlling the direction and command means for setting and indicating the desired direction. The invention also relates to a method for regulating the position and controlling the direction of a jet directing means in a water jet propulsion apparatus to be used in boats.

A water jet propulsion drive apparatus to be used in boats and vessels comprises a closed "screw propeller apparatus, which is rotated by a driving motor. From the outlet end of said pro¬ pulsion drive a water jet is directed with high speed back¬ wards with respect to the traveling direction of the boat. Under the impact of the continuous impulse from this water jet the boat or the vessel moves in the opposite direction with regard to the jet. Thus the movement direction of the boat or vessel is defined by the direction of the water jet, whereby the directing of the movement of the boat is effected by controlling the direction of said jet.

A usual directing approach used in water jet propulsion drives is that the directing in the lateral direction is performed by turning a nozzle located in the back end portion of the jet apparatus in such a manner, that the water jet is directed laterally according to the movements of the steering wheel.

In a corresponding manner the braking, remaining in place and reversing of the boat usually is arranged so, that a clamshell shaped directing gate means is brought in the way of the water jet discharging from the directing nozzle so that the jet hits the clamshell shaped directing means and therefrom is directed downwards or backwards under the boat in accordance with the command lever' s control.

The deflection of the water jet direction from a direction straight backwards demands a power impact in order to overcome the pressure effect generated by the jet. In the lateral directing the amount of angular deflection of the jet usually is rather low in relation to the force at disposal, because the transmission ratio of the steering wheel may easily be arranged in the traditional manner to a level which provides a sufficient force. In the reversing operation, however, the situation is different. The braking and reversing of the boat must be quick and easy to control. In traditional boat drive arrangements the motion of the command means controlling the engaging and reversing is rather short, and it would be desirable, from the user' ε point of view that similar control conditions prevail also for water jet propulsion drives.

In this connection it may be observed, that the efficiency for the reversing operation in a water jet propulsion drive is considerably higher than in traditional screw propeller drive units, because the screw propeller establishing the water jet does not need to change its rotational direction to be opposite in relation to the moving mass of water. In the prac¬ tice this efficiency, however, demands that the pressure from the water jet must be overcome before the directing gate means can be located in such a position that the direction of the water jet changes. With a proper design of the directing gate the pressure effect may be reduced or even almost totally sup¬ pressed, but then there appears the problem, that the control becomes unstable, whereby for example the braking may become dangerously abrupt. In practice it has been proven, in balanced arrangements, that bringing the directing gate in front of the water jet often demands so high a force, that the controlling is difficult, a rather high strain thus being exerted upon the command means.

In larger water jet propulsion drives there have been used chiefly hydraulic means for increasing the efficiency of the controlling, whereby the command means act upon valves which then control hydraulic means effecting the movement of the directing gate means. Hydraulic means are, however, in marine conditions quite sensitive to malfunctions, and they always demand a special hydraulic pump, which one may be reluctant to install in smaller boats.

In order to overcome this problem the arrangement according to the invention has been developed, the characteristics of which will be clear from the appended claims. The invention thus i characterized in that a preferably electrically operated power means extends between the lever which causes the movement of the directing gate means and a fastening point which is fixed with respect to the controlled apparatus. In this case the fastening point suitably comprises the hull of the boat. The function of said power means is dependent on the mutually centered disposition of said lever and a control piece con¬ nected to said command means in such a way that said power means is non-operative when said control means is, within a suitable clearance, in a predetermined position with respect to said lever, and that said power means strives to restore said lever into said disposition if a predetermined deviation occurs. In practice this means that said lever under the im¬ pact of said power means is forced into a new centered posi¬ tion which corresponds to the new position of said control piece.

The method according to the invention is on the other hand characterized in that the controlling of the movement of the electrically operated power means arranged for pivoting the lever is effected by detecting the position of said lever in relation to said control piece, which piece moves in accordance with the movements of said command means and is movable at least to a certain extent in relation to said lever. A detected displacement of said control piece from a predetermined mutual disposition in relation to said lever is transformed into control signals for the preferably electri¬ cally operated power means to restore said centered dis¬ position.

An embodiment of the invention will now be explained with reference to the enclosed drawing, where, for clarity, the connection between the control device and the command lever is shown cut off.

Figure 1 shows a lever arm 1 one end of which is connected, via a shaft 2, to a directing gate means (not shown) for the water jet. In this embodiment the electrically operated power means moving said lever arm 1 is a spindle motor 3, which in the illustrated case is connected to the end of said lever arm 1 via a link 4.

According to the invention said spindle motor 3 is controlled according to the mutual disposition of said lever arm 1 and a control piece 5. In the disclosed embodiment said control piece 5 comprises a plate-like member, which is connected to said command means, in other words- to said command lever 7 via a command wire 6 which is movable back and forth. When said command lever 7 is moved said command wire 6 will move in its protective pipe 8 and this will urge said control piece 5 to move forwards or backwards in accordance with the movements of the end 9 of said command wire 6.

In the shown embodiment said control piece 5 comprises an elongated slot 10 extending in the direction of said end 9 of said command wire 6 and, correspondingly, in a tangential direction in relation to the direction of movement of said lever arm 1. Thus said control piece may move slightly in a direction tangential to said lever arm 1. A retaining pin 11 extending from said lever arm 1 through said slot 10 holds said control piece 5 closely but movably in contact with said lever arm 1. Another embodiment further comprises a guide means keeping said control piece 5 in an essentially tangential position even in a case where the pivoting of said lever arm 1 is considerable.

Due to the possibility for said control pi.ece 5 to slightly move, within the extension of said elongated slot 10, in re¬ lation to said lever arm 1 the mutual movement between said lever arm 1 and said control piece 5 primarily causes a con¬ tact means on said lever arm 1 to act upon switches 12, 13 arranged on both sides on said contact piece 5. In the dis¬ closed case said contact means comprises a retaining pin 11. Thus a deviation of the positions of said lever arm 1 and said control piece 5 from a predetermined mutual disposition with respect to each other effects the functioning of one of said switches 12, 13. Said switches 12, 13 are directly or preferably via control relays connected to said electrical spindle motor 3 in such a way, that the switch 12 will switch on said motor 3 so that the motor arm 14 of said motor 3 will strive to pivot said lever arm 1 in a clockwise direction, as seen in said Figure, and the switch 13 will bring about a function in the - opposite direction. Thus the switching function of each of said switches 12, 13 will cause said spindle motor 3 to exert a force in a direction which strives to bring said lever arm 1 back to said predetermined centered disposition in relation said control piece 5.

In the disclosed embodiment said switches 12, 13 comprise micro-switches arranged oh said control piece 5 in such a way, that switch buttons 15, 16 or the like on said switches 12, 13 are located one in each end of said elongated slot 10. Thus said guiding or retaining pin 11 or the like attached to said lever arm 1 and moving in said slot 10 may act on one or the other of said buttons 15, 16. A corresponding switching function then takes place each time said pin 11 comes into the vicinity of one or-the other end of said slot 10. The distance between the above switching position and said centered position may easily be adjusted in order to obtain a proper clearance and/or delay, whereby any vibrations from engine or waves will not cause any unnecessary switching functions.

Alternatively said switches 12, 13 may be arranged so that they are fastened fixedly with respect to said lever arm 1. Said control piece 5 then comprises extending brackets or the like which may act upon one or the other of the switches when said control piece, due to the function of said command lever 7 via said wire 6, moves away from said predetermined centered disposition with respect to said lever arm 1.

The arrangement according to the invention works in the described embodiment so, that a displacement of the position of said control piece 5 in relation to said lever arm 1 is de¬ tected by detectors on said switch means 12, 13, said detectors being located on both sides in relation to said lever arm 1. Said control piece 5 is then, in order to achieve a pivoting of said lever arm 1, made to move, in accordance with the movements of said command lever 7, into a position deviating from said centered position. In said deviating position the mutual displacement between said control piece and said lever arm causes a switching function in one or the other of said switches 12, 13. This switching function results in that said electrically operated power means, suitably said spindle motor 3, in accordance with the command from the respective one of said switches 12, 13 forces said lever arm 1 to pivot into a predetermined centered disposition in relation, to the new position of said control piece 5.

Upon the function of a spindle motor 3 or the like electri¬ cally driven power means said lever arm 1 thus strives to pivot in such a manner, that it remains in a disposition which can be predetermined, suitably in a centered position, in. relation to said control piece 5. A movement of said command lever 7 causes said control piece 5 to move, within the clearance allowed by said slot 10, to a new position. The respective one of said switches 12, 13 then switches on said spindle motor 3 so that said lever arm 1 will be forced into the same direction until said centered disposition is achieved, at which point said switch 12, 13. disconnects and said movement ceases. Said lever arm 1 then remains in a posi¬ tion that corresponds to the position into which said command lever 7 is set. The moving of said command lever 7 will thus be very easy because said spindle motor takes care of the work proper, in this case the bringing of said directing gate into the path of the water jet in order to deflect its direction.

In order to secure a centered position it may, in some cases, be preferable, that said control piece 5 is precentered on said lever arm 1 with aid of springs, ε-o that said control piece automatically tends to home . into such a position when said command lever 7 is not forcibly moved. Such an arrange¬ ment resets said command lever 7 so that said lever 7 exactly shows the position of said lever arm 1. Each movement of said command lever 7 takes -place against this suitably adjustable spring force, and the arrangement also secures a certain clearance between the movement of said command lever 7 and the on-switching of the crontro-1 function, so that minor movements in said command wire 6, caused by e. g. beating of the waves, not will start any command functions.

In another simple embodiment a damping is achieved by arranging a frictional brake in the lower part 19 of said com¬ mand lever 7. In order to quickly stop the movement of said spindle motor 3 in the exact position the switching of the spindle motor 3 is arranged, in a favourable embodiment, so that said spindle motor is short-circuited when the positive guidance from said switches has ended. The movement of said lever arm 1 then stops very quickly when the respective switch 12 or 13 is released.

In some cases it may, on the other hand, be favourable, that the end 9 of said command wire 6 proper is flexibly connected to said control piece 5. Due to the spindle motor' ε limited speed of motion a too .quick movement of said command lever 7 may otherwise lead to a situation wherein said spindle motor 3 does not have time to pivot said lever arm 1 at a speed cor¬ responding to the movement of said command lever 7. Any ex¬ cessive movement may then act against said flexibility and no harm will occur. In the embodiment described said movement simply stops when said retaining pin 11 touches end surfaces 17, 18 of said elongated slot, whereby the resistance in said command lever 7 increases and the driver notices that the command movement is to violent.

The respective position of the reversing gate or e. g. a directing nozzle always appears from the position of said command lever 7. In the case of a reversing gate this com¬ prises especially important information, because a water jet propulsion device normally has no actual disengagement clutch, and any movement,of the boat at the starting moment is pre¬ vented by directing the jet straight downwards. For this position said spindle motor 3 suitably has a positively switched "centering" possibility, so that said lever arm 1 and said water jet directing gate connected thereto as well as said control piece 5 and said command lever 7 connected there¬ to automatically are driven into the "free" position of the water jet. Such a function is also applicable to the lateral direction of the water jet, so that said water jet always will be directed straightly downwards during the engine startup.

An electrical spindle motor 3 is especially favourable since its speed of motion may be chosen or adjusted so that the gate directing the water jet forwards under the boat cannot work so quickly, that any danger for the passenger arises due to an abrupt change of direction of the motion. This danger normally does not exist in normal screw drives, but due to the better operating efficiency in water jet propulsion drives such a danger is connected especially to stopping and reversing pro¬ cedures. The speed of motion of the spindle motor thus pre¬ ferably is adjusted so that the speed with which the directing gate is moved into the path of the water jet is lower than the speed with which said gate is moved out of said path, i. e. in a situation when the boat may freely accelerate forwards. Said speed of motion may also be set proportional to the rotational speed of the engine, so that the movement is slower when the rotational speed and thus the water pressure and the risk of damage is higher.

The electrically operated power control described above is especially favorable in smaller boats, since electricity usually is available and since said apparatus is rather simple and solid. The installation of electrical equipment is easy and the equipment is conveniently located so that it is pro¬ tected from water splashes. Because the advantages of electri¬ cal apparatuses, compared e. g. to hydraulic servo equipment, lie among others in the fact, that they are easy to protect from oxidation and corrosion, are simple in construction, while still permitting a completely free location even outside the hull of the boat. In particular, in the case when totally closed so called Reed-relays working on the. principle of mag¬ netic impact, or e. g. optical switch means are used as switches 12, 13 the electrical connecting is especially durable in marine conditions.

For emergency use it may sometimes be favourable that the control also may take place using completely mechanical means and independent of any electrical, power- - control. For this purpose control piece 5 and the command means 6, 7, and 8 suitably are dimensioned in such a way, that they endure also a direct operation of said lever arm 1 without the aid of said spindle motor 3. In that case said control piece 5 advantageously comprises impact faces, which in the embodiment described are the end faces 17, 18 of said elongated slot 10, said control piece 5 thus being able to impact, under positive operation, directly on said lever arm 1. In such a situation said link 4 between said lever arm 1 and said spindle motor 3 suitably should be opened. The operative efficiency in emer¬ gency situations is enhanced in such an arrangement, where said control piece 5 is located outwards from said link point 4 of said spindle motor 3 when seen from said shaft 2. Gene¬ rally it can be stated, in this connection, that the sensi¬ tivity of the command function easily may be adjusted by the location in which said control piece is positioned on said lever arm 1 in relation to said shaft 2.

Above there has been disclosed a command arrangement mainly for the free engagement and reverse functions. A similar ar¬ rangement may, however, also be applied for the command in the lateral direction, even though, as discussed above, the force resources at hand there usually are higher in relation to the forces needed. Even though the discussion above has con¬ centrated on the most favourable arrangement utilizing an electrical spindle motor the invention should be seen, within the scope of the claims, also to comprise other then power means arrangements, which in some cases may be other electri¬ cally driven means, e. g. hydraulic or pneumatic power means or combinations of these. The switches may also be of any other kind of switching means, which upon mechanical command control the function of the power means mentioned above. It is also evident, that the different details of the invention may vary from the embodiment described above and within the scope defined by the claims.

Claims

Claims

1. Control arrangement especially for controlling the direction of a water jet propulsion drive apparatus to be used in boats, said arrangement comprising a direction control lever means (1), power means (3) extending between said lever means (1) and an attachment point which is fixed with respect to said apparatus to be controlled, and command means (7) for setting and indicating the desired direction, c h a r a c t e ¬ r i z e d in, that said arrangement comprises a control piece (5) connected to said command means (7) and movable on said lever means (1), said command means (7) being independent of the function of said power means (3), said power means (3) being connected to function in order to maintain a mutual centered disposition between said control piece (5) and said lever means (1), so that said power means (3) is non-operative when said control piece (5) is, within a suitable clearance, in a predetermined disposition with respect to said lever means (1), and that said power means (3) is arranged to move said lever means (1), when a predetermined deviation occurs, to a position which is centered to correspond to the new position of said control piece (5).

2. An arrangement as defined in claim 1, c h a r a c t e ¬ r i z e d in, that said control piece (5) is arranged movably on said lever means (1) in such a way that a relative movement between said lever means (1) and said control piece (5) pri¬ marily acts upon switches (12, 13) or the like, which are ar¬ ranged on both sides on said control piece (5) and/or on said lever means (1), in such a way that a deviation of the positions of said lever means (1) and said control piece (5) in relation to each other from said mutual centered dis¬ position effects the funαtion of one of said switches (12 or 13), whereby said switch (12, 13) effects a power impact from said preferably electrically driven power means (3), suitably a spindle motor, which impact aims at the restoration of said lever means (1) into said centered disposition with respect to said control piece (5), spring means preferably being located between said lever means (1) and said control piece (5) in order to maintain said mutual centered disposition when said command means (7) is released.

3. An arrangement as defined in claim 1 or 2, c h a r a c t e ¬ r i z e d in, that said switches (12, 13) or the like are so arranged on said control piece (5) that said switches (12, 13) comprise switch buttons (15, 16) and/or suitably magnetically operated switches and/or optical switches and/or the like arranged one at each end (17, 18) of an elongated slot (10) in said control piece (5), whereby a guide pin (11) or the like contact means fixed to said lever means (1) and moving in said slot (10) may impact upon one or the other of said buttons (15, 16) or the like, thereby effecting a switching function when said pin (11) is located in the vicinity of one of said ends (17, 18) of said slot (10).

4. An arrangement as defined in claim 1 or 2, c h a r a c t e ¬ r i z e d in, that said switches (12, 13) or the like are arranged fixedly with respect to said lever means (1), whereby brackets on said control piece (5) may act on one of said switch buttons (15 or 16) and/or the like in one or the other of said switches (12 or 13) or the like when said control piece (5) is'positioned, within a suitable clearance, outside said mutual centered position with respect to said lever means (1).

5. An arrangement as defined in one of the above claims 1...4, c h a r a c t e r i z e d in, that said control piece (5) is connected to a command lever (7) via a control wire (6) in such a way, that a movement of said command lever (7) effects a tangential movement of said control piece (5), suitably a control plate, in relation to the movement trajectory of said lever means (1), said control wire (6) preferably being resiliently fixed to said control piece (5), whereby said arrangement suitably comprises guide means for keeping said control piece (5) in an essentially tangential direction with respect to said lever means (1).

6. An arrangement as defined in one of the above claims 1...5, c h a r a c t e r i z e d in, that said control piece (5) comprises impact faces (17, 18) which mechanically impact upon said lever means (1) for allowing a positive guidance in a case of emergency.

7. An arrangement as defined in one of the above claims 1...6, c h a r a c t e r i z e d in, that said power means is an electrically operated means, suitably a spindle motor (3), the speed of motion of which suitably being so adjusted, that said speed is different in the different directions of movement.

8. An arrangement as defined in on of the above claims 1...7, c h a r a c t e r i z e d in, that one or several electrical power means (3) comprise a positively guided centering func¬ tion, which suitably is so switched, that a starting up of the driving engine of the vessel automatically centers said lever means (1) into a position where the water jet stream is directed straight downwards.

9. A method for controlling a device which is provided with a lever means, which method is especially adopted for control¬ ling the position of the directing means for a water jet pro¬ pulsion drive and wherein the pivoting of said lever means (1) is provided by the movement of a power means (3), c h a r a c ¬ t e r i z e d by controlling the movement of said power means (3) by detecting the position of said lever means (1) in relation to a control piece (5) moving in accordance with the movements of a separate command means (7), said control piece (5) being at least partially movable in relation to s_ai lever means (1), whereby a detected deviation of said control piece (5) from a predetermined mutual disposition in relation to said lever means (1) is transformed into a control signal for said power means (3) to restore said mutual centered dis- position so that said lever means (1) is brought to move to a new centered disposition corresponding to the new position of said control piece (5).

10. A method as defined in claim 9, c h a r a c t e r i z e d by detecting, with the aid of the movement of switch buttons (15, 16) or the like means arranged on said switch means (12, 13) and located on each side of said lever means (1), a de¬ viation of the position of said control piece (5) in relation to said lever means (1), whereby, in order to effect a pivoting of said lever means (1), said control piece (5) in accordance with the movement of said command means (7) is forced to move from said mutual centered position to a deviated position, where the mutual deviation of the positions of said control piece (5) and said lever means (1) brings about a switching function in one or the other of said switches (12, 13) in such a way, that said preferably electri¬ cally driven power means (3), suitably said spindle motor, under the control of said switch (12 or 13) is brought to force said lever means (1) to pivot into a mutually centered position with respect to the new position of said control piece (5).