Water jet propulsion boat

Abstract: The present invention relates to a water jet propulsion boat comprising an engine powered jet unit having a jet nozzle and a reverse gate hingedly connected to said jet nozzle in order to deflect the water jet ejected from the jet nozzle, and first and second actuating means for changing the position of the reverse gate with respect to a jet opening of the jet nozzle and for controlling the throttling action of an engine for adjusting the performance thereof wherein, the first actuating means comprises a shift handle (42) which is shiftable between forward, neutral and reverse positions, wherein a guide means (41) for controlling the travel of the shift handle between said positions is provided preventing the shift handle from being shiftable between the forward and rearward positions by a straight single stroke.

Description: The present invention relates to a water jet propulsion boat comprising an engine powered jet unit having a pair of jet nozzles and a reverse gate hingedly connected to said jet nozzles in order to deflect the water jet ejected from the jet nozzle, and first and second actuating means for changing the position of the reverse gate with respect to a jet opening of the jet nozzle and for controlling the throttling action of an engine for adjusting the performance thereof, wherein the first actuating means comprises a pair of shift handles which are shiftable at least between forward and reverse positions, wherein a guide means for controlling the travel of the shift handles between said positions is provided preventing the shift handle from being shiftable between the forward and the rearward positions by straight single stroke. Recently, water jet propulsion boats have been widely used for planing over water at high speed and enjoying various sportive movements. Generally, such a jet propulsion boat includes a jet unit propelling the small boat equipped with an engine planing over the water by suctioning water through the hull bottom and injecting same through a jet nozzle rearward from the stern of the boat in the desired direction. Such boats are highly manoeuvrable water crafts suited not only for high speed planing over the water but also for abrupt turning, stopping, etc. In order to improve the manoeuvrability of the boat the function of a steering deflector has been developed by installing a reverse gate on the jet nozzle said reverse gate being adjustable into a position opposite to the jet nozzle facing the nozzle opening thereof attributing a reversing function to the boat, as the afore-mentioned "reverse position" of the reverse gate opposite to the nozzle opening leads to a reversal of the water jet ejected from the jet nozzle. When the reverse gate is shifted in its "normal position" not obstructing the water jet downstream of the nozzle the reverse gate takes a "forward position" at which the normal water jet propulsion function is obtained driving the boat forwardly. By means of shifting the reverse gate into its reverse position facing the opening of the jet nozzle and reversing the water jet an extremely great breaking force can be generated and, accordingly, the speed of the boat can be abruptly reduced acquiring an excellent speed reducing performance of the boat. However, an immediate shift of the reverse gate into its reverse position while running the boat at full speed forwardly causes problems in that the speed reducing force exceeds desirable values and applies an uncomfortable shock to the crew members which should be avoided. Moreover, a drastical speed reduction should also be recognizable from other boats running behind. In order to relieve the afore-indicated shift shock it could be contemplated to adjust the throttle undelayed after the reverse gate is shifted to its reverse position. A water jet propulsion boat comprising an engine powered jet unit having a pair of jet nozzles and a reverse gate as indicated in the preamble of claim 1 is disclosed in US-A-3 797 447. In that case, a single engine drives a single jet unit with branched bowl segments. Thus, a single throttle actuating means is provided which is disposed aside of the shift actuating means, and as a consequence of this, the operator has to pay attention to the coordination of his operating hand, in order to avoid mixing up of shift and throttle levers. Moreover, the operator's body has to be turned toward the levers, which is undesirable for coping with the problems of an ergonomical adjusted operation. Accordingly, it is an objective of the present invention to provide a water jet propulsion boat having a high speed reducing responsiveness as well as excellent reverse running function and speed running performance but which allows a shifting shock applied to the crew members when switching from a forward running operation to a reverse running operation to be drastically reduced or even prevented by means of a simple operating structure, thus assuring a smooth operation of the boat, while allowing an ergonomical adjusted operation According to the present invention the afore-indicated objective is performed by a water jet propulsion boat as indicated above wherein a boat drive system comprises a pair of engines driving a pair of jet units, the second actuating means comprises a pair of throttle levers and together with the first actuating means enabling to operate each drive train composed of an engine-jet unit arrangement separately, and that casings of the shift and throttle actuating means accommodating the associated shift and throttle levers are disposed in alignment to each other with the throttle levers disposed behind the shift lever in the direction of the shift lever operation, and the shift and throttle levers are disposed such that the throttle lever in its fully opened position is disposed just behind the shift lever set in its reverse position, both levers being operated in the longitudinal direction of the boat. In this way the guide means forcedly guiding the shift handle along a non-straight travelling path between the forward and rearward positions serves to assure that a certain time lag occurs and some time is required to shift from the forward state to the reverse state thus minimizing an evil caused by an excessive speed reducing effect while a rapid breaking and shifting to the reverse running condition is performed from a forward full speed running condition of the boat. Furthermore, the provision of the shift and throttle means of the present invention fulfills the requirement of an ergonomical operation. Not many coordination abilities are demanded from the operator if the levers are arranged one behind the other. It is assured that the throttle lever can be grasped immediately after the shift lever is shifted into the reverse position. Preferably, the shift handle is a shift lever swingably supported through a ball joint disposed in a shift casing which, in turn, defines a guide groove for guiding the travel of the shift lever between said forward, neutral and reverse positions wherein said guide groove comprising a straight portion connecting the forward and neutral positions and an offset portion connecting the neutral and reverse positions with a step portion provided in between the straight and offset portions of the guide groove. Accordingly, preferably the guide groove has a substantially Z-shaped configuration According to yet another preferred embodiment of the present invention a second actuating means for adjusting the throttling condition of the engine is disposed adjacent to the first actuating means, which is the shift actuating means. In this way, the throttle of the engine can be immediately changed and adjusted to an appropriate value after the reverse gate is shifted to the reverse state as both handles for performing a shift operation and adjusting the throttling action of the engine are disposed closely adjacent to one another. According to another preferred embodiment of the throttle actuating means the throttle handle forms a pair of joint throttle levers disposed behind the pair of shift levers in the longitudinal direction of the boat wherein both types of levers being installed near the driver's seat. According to yet another embodiment of the present invention the casing of the throttle levers can be disposed to be laterally offset outwardly with respect to the casing of the shift levers disposed ahead of the throttle casing. Quick operation of both the shift and throttle levers can be facilitated by means of positioning the grips of the shift and throttle levers at about the same height when the shift lever is in its reverse position and the throttle lever is in its fully open position. According to further embodiments of disposing the shift and throttle levers the lateral offset of the shift and throttle casings can be used to dispose the shift and throttle levers in an overlapping condition (in side view) when the shift lever is in its reverse position and the throttle lever in its fully open position. Moreover, according to yet other preferred embodiments of the present invention a distance may also be provided between a pair of shift levers being in their reverse position and a pair of throttle levers being in their fully open position leaving a space for the fingers of the operator for convenient actuation. According to yet another preferred embodiment the height of the grip of the shift lever in the reverse position can also be different from the height of the grip of throttle lever in the full throttle (open) position. According to another embodiment operation of the shift and throttle levers can be facilitated in that the shift lever and associated shift casing are positioned on a slope reducing the operational space required for actuating the shift and throttle levers. Finally, it is also possible to change the disposal of the shift and throttle casings and associated levers in view of the longitudinal direction of the boat, i.e. disposing the throttle case with the one or two throttle levers ahead of the shift casing and associated one or two shift levers. In order to provide a warning to other boats planing behind the boat and to indicate the abrupt reduction of the travelling speed of the boat or change of the travelling direction from a forward to a rearward movement, according to yet another preferred embodiment of the present invention, it is preferred that a reverse state indicating means is installed on the stern of the boat, preferably rear lights are provided in conjunction with a switch means wherein said switch means is actuated in response to a movement of the shift lever or the reverse gate, respectively, to switch on the rear lamps when the shift lever is actuated from a forward position to the neutral or specifically to the reverse position. Further preferred embodiments of the present invention will become yet more apparent from the following description of several embodiments thereof inconjunction with the accompanying drawings wherein: Figure 1 is a side elevational view of a water jet propulsion boat designed in compliance with an embodiment of the present invention, Figure 2 is a plane view of the boat according to Figure 1, Figure 3 is a back view of the boat according to Figures 1 and 2, Figure 4 is a schematic diagram of the indicator means at the stern of the boat and an associated electrical circuit, Figure 5a is a side view of a reverse gate pivotably supported through a jet nozzle in the forward running state including a switch means for actuating the indicator means in response to the position of the reverse gate, Figure 5b is a side view similar to Figure 5a showing the reverse gate in its reverse running state, Figure 6 is another embodiment of the switch means for powering the indicating means in response to a shift lever position, showing a detail of a base end portion of a shift handle, Figure 7 is enlarged plane view of the area of a driver's seat portion including a shift and throttle operating casing, Figure 8 is a partial plane view of a shift actuating device, Figure 9a is a perspective view of the reverse gate and its shift actuating device in the forward running state, Figure 9b is a perspective view of the reverse gate disposed at the jet nozzle in the reverse running state, Figure 10a is a plane view of a guide groove for the shift lever similar to Figure 8, Figures 10b to 10e are explanatory illustrations for elucidating the reverse gate shifting process corresponding to the respective positions of the shift lever indicated in Figure 10a, Figure 11 is a side view illustrating the disposition of a shift handle and a throttle handle of the shift and throttle actuating means, Figure 12 is a plane view of a disposal of the shift and throttle casings supporting the shift and throttle levers according to another embodiment of the present invention, Figure 13 is a schematic side view of the shift and throttle levers according to Figure 12, Figure 14 is a plane view similar to Figure 12 disclosing another embodiment of disposing the shift and throttle casings, Figure 15 is a schematic side view of the shift and throttle levers according to Fig. 14. Figure 16 is a side view similar to Figure 15 disclosing another embodiment of the disposal of the shift and throttle casings according to the present invention, Figure 17 is a schematic view similar to Figures 13, 15 and 16 disclosing yet another embodiment of the present invention, Figure 18 is a plane view similar to Figures 12, and 14 for yet another embodiment of the present invention, wherein the throttle casing is disposed ahead of the shift casing in the longitudinal direction of the boat, and Figure 19 is schematic a side view of the shift and throttle levers according to Figure 18. In the following the basic design of the water jet propulsion boat according to an embodiment of the present invention is explained referring to Figures 1 to 3. As shown therein, the water jet propulsion boat comprises a boat body 10 which is formed by joining a hull member 10b and a deck member 10a with each other at their peripheral portions as is conventional in the art. The body 10 of the boat houses a space substantially hermetically closed to constitute the displacement volume and, moreover, defining an engine compartment 18 therein. A cockpit 19 is provided between both bulwarks 20 comprising a steering wheel 14 supported on a dashboard on the front end of the cockpit 19. A windshield 16 is installed on the front side of the cockpit 19 and a pair of chairs is provided in a side-by-side arrangement in the cockpit 19 each of them being composed of a seat back 11 and a pair of seat plates or cushions 12, 13 formed on the front and rear side of the seat back 11. The steering handle 14 is disposed on the right-hand side of the cockpit to be operated from a driver sitting on the right-hand seat plate 12 having control boards on the right-hand side of the driver's seat comprising a shift casing 40 with a shift handle composed of a pair of shift levers 42 and a throttle casing 21 with a throttle handle composed of a pair of throttle levers 22 enabling the driver to shift the propelling power between forward and reverse directions, a forward speed reduction position or chosing a neutral position in between (see Figure 7). The throttle levers 22 serve for adjusting the throttling action of the engine and, therefore, the performance in propelling the boat. As is apparent from Figures 1 and 2, the engine compartment accommodates a pair of engines 23 in a side-by-side arrangement as well as further equipment of the drive system, such as fuel tanks (not shown) etc., and a pair of jet units 24 connected to the associated engines 23, respectively. Each jet unit 24 comprises a water flow passage extending from a water suction port at the hull bottom rearwardly to the stern of the boat accommodating an impeller shaft with an impeller fixed thereon, said impeller shaft being fixed to the engine by a transmitting shaft. The water flow passage at its end portion downstream of the impeller terminates into a conical jet nozzle 26 for generating the propelling force and the turning force for the boat, said jet nozzle 26 or component thereof such like a deflector being rotatably supported about a vertical shaft providing a propelling water jet at the rear end of the flow passage. As shown in Figures 9a and 9b the jet nozzle 26 has an integral arm 51 formed at one side thereof and is swivelled about a vertical shaft 53 by pushing or pulling this arm 51 through a steering cable 52. Accordingly, the boat body 10 is propelled and turned in the desired direction by sucking water through the suction port of the hull bottom by the impeller rotating in the flow passage, and by ejecting said water rearwards from the jet nozzle 26 in the desired direction when the impeller is driven by the engine 23. As for example is described in the applicant's European patent application 91 112 357.8, a reverse gate 27 is provided which is supported by the jet nozzle 26 of each jet unit 24, respectively, said reserve gate 27 being adapted to be rotatably supported at the nozzle 26 or a component thereof such like a deflector, to be pivotable about shafts 28 extending horizontally on both sides of the jet nozzle 26. Accordingly, as indicated in Figures 10b to 10e the reverse gate 27 can rotatably be shifted between its forward position leaving the jet opening of the jet nozzle 26 completely unobstructed running the boat forwardly (Figure 10b) and its reverse position (see Figure 10e) disposing the reverse gate 27 opposite to the nozzle opening of the jet nozzle 26 creating a rearwardly propelling force to stop further forward movement of the boat propelling same in a reverse direction through the forwardly directed water jet. For the purposes of this application it should be noted that the term "jet nozzle" also comprises an arrangement as indicated in Figures 10b to 10e, wherein a deflector is provided at the rear end of the jet nozzle and is provided to be pivotably about a vertical axis whereas the actual nozzle is fixed and wherein said deflector also rotatably supports the reverse gates 27. In this description, however, the deflector and the jet nozzle are considered as a unit and, thus, the general use of the term jet nozzle includes the arrangement of a deflector as well. Accordingly, within the meaning of this application the deflector and associated rear of the jet nozzle are considered as a unitary structure and, accordingly, characterizing the reverse gate 27 to be rotatably supported by the jet nozzle 26 also covers the structure that the rear gate 27 is supported through the deflector which in turn is rotatably supported by a rear end of the jet nozzle tube as shown in Figures 10b to 10e. Accordingly, the support structure for the reverse gate 27 as shown Figures 10b to 10e can be the same a explained in greater detail in the applicant's afore-mentioned European patent application 91 112 357.8. The afore-indicated disposal of the reverse gate 27 leads to an excellent manoeuvrability of the boat and provides several options for a sudden stop sharp curve rearward propelling or other sportive movement to be performed. In order to provide a warning to other water crafts behind the jet propulsion boat signalizing that a speedy forward movement is either stopped or even turned to the reverse, the rear portion of the boat body 10 comprises cavities 30 accommodating an indicator, such as a rear lamp, therein. As is indicated is Figures 3 and 4 a pair left and right indicators 31 are provided associated to the pair of left and righzt jet units 24 and a battery 33 is provided as a source of energy for said indicators 31. Moreover, a pair of left and right switches 60 are provided associated to the pair of indicators 31. The switches 60 are adapted to be actuated jointly or separately depending on the mode of operating the jet units 24 and associated reverse gates 27 jointly or separately. Of course, the boat can also be provided with one jet unit 24 only and one indicator 31 or a pair of jet units 24 and one indicator 31 only. Different embodiments of actuating the switches 60 and, accordingly, signalizing a change of the driving condition of the boat in response to an operation of the shift handle 42 and a resulting swivelling of the reverse gate 27 into or out of its reverse position are explained referring to Figures 5a, 5b and 6. As shown in Figure 5, a running condition detection switch 60, for example, can be installed at the nozzle housing near a base end portion of the reverse gate 27 said end portion being formed as an actuating projection 29. Accordingly, by pivoting the reverse gate 27 into its reverse position a contactor 61 of the switch 60 can be operated to switch on the indicator 31 indicating that the forward running condition of the boat is no longer maintained. Depending on the disposal of the switch 60 the timing of energizing the indicator 31 can be determined, accordingly, the indicator can already be switched on when the shift handle 41 moves from a forward position into a neutral position or when the shift handle 42 is operated from a neutral position into a reverse position or, ultimately, when the reverse gate reaches its reverse position and, accordingly, the shift handle 42 has reached its reverse position. Another embodiment of locating the indicator switch 60 is shown in Figure 6 wherein the switch 60 is installed near a base end portion of the shiflever handle 42 which, in turn, is provided with an actuator projection 44a opposite to the switch 60 ensuring that the contactor 61 of the switch can be operated by the cam 44a of the base end portion 44 to be actuated when the shift lever 42 is moved from its forward position towards its reverse position. Apparently the timing of switching on the indicator again can be chosen by determining timing of engagement betwen the cam 44a and contactor 61 during the travel of the shift lever 42. In this way, when the boat body 10 planes forward, the reverse gate 27 and the shift handle 42 are in the state shown in Figures 5a and the "F" indicated in dotted lines in Figure 6. In order to propel the boat rearward, the shift lever 42 is transferred to the reverse position denoted in Figure 6 as R-position in phantom lines to rotate the reverse gate 27 about the shafts 28 through the shift cable 43 to the state opposite to the jet opening of the jet nozzle 26 as shown in Figure 5b to reverse the water jet from the jet nozzle 26. (See also Figure 10e). When the reverse gate 27 is shifted towards to reverse condition while running at high speed either the projection 29 at the base portion of the reverse gate 27 actuates the switch 60 to switch on the indicator (rear lamp) 31 when the reverse gate 27 rotates and reaches the state shown in Figure 5b, or the projection 44a of the base end 44 of the switch lever 42 actuates the switch 60 to switch on the indicator 31 (as indicated in Figure 6) and, accordingly, the change of the driving condition and the travelling direction as well as an abrupt speed reduction of the boat are signalized to the crew members of other boats running behind thus avoiding accidents to occur. In the following the design, disposal and layout of a first and second actuating means for shifting the propelling direction of the boat is response to a position of the reverse gate 27 with respect to its associated jet nozzle 26 and the throttling of the engine 23 powering the jet unit 24, will be explained in greater detail by referring to Figures 7 to 18, respectively. As was already indicated above the water jet propulsion boat embodying the present invention as shown in Figures 1 to 3 is equipped with a boat drive system comprising two parallel drive trains each comprising an engine 23 powering a jet unit 24 with a jet nozzle 26 and reverse gate 27 at the end of each drive train. In view of this design it is preferred that each of the engine/jet unit-arrangements can be operated independently from each other. Accordingly, the first actuating means adapted to rotate the reverse gates 27 of the jet units 24 to select a forward, rearward or neutral propelling direction is embodied to comprise a pair of shift levers 42 each disposed in a side-by-side arrangement accommodated through a joint shift casing 40 and adapted to operate the right or left reverse gate 27, respectively (see Figure 7). Similarly the second actuating means for controlling the performance of the engines 23 by adjusting the throttling thereof comprises a pair of throttle levers 22 accommodated in a common throttle casing 21. As shown in Figure 7, the both shift and throttle levers 42, 22 disposed at the right outer side (as seen from the driver's position) are adapted to operate the engine 23 at the right-hand side of the driving arrangement of the boat and the reverse gate 27 of the associated jet unit 24, respectively. Accordingly, both the shift and throttle levers 42, 22 disposed at the left inner side are adapted to operate the left engine 23 at the left-hand side of the driving arrangement of the boat and the reverse gate 27 of the associated jet unit 24, respectively. For ease of explanation in the following normally reference is made only to one of said shift and throttle levers 42, 22 and it should be understood that the other one (for the other engine/jet unit arrangement) can be disposed, operated or designed correspondingly. Moreover, the present invention of course can also be embodied by means of using a single drive train composed of one engine 23 and one jet unit 24 using only one shift lever 42 and one throttle lever 22, respectively. As indicated above the abrupt speed reduction which can be acquired by switching the reverse gate from a position as shown in Figure 10b running the boat forwardly under high speed conditions into a reverse position as shown in Figure 10e propelling the boat backwards may render the passengers or other crew members to feel uncomfortable due to the evil accompanying immediate change of the travelling directionfrom speedy forward movement to a rearward movement of the boat. In order to overcome these deficiencies an effective shift lever operating structure was chosen. As shown in Figures 7, 8, 9a and 9b each shift lever is accommodated in a shift casing 40 projecting upward from said shift casing 40 through an upper wall of the casing and terminating in a hand grip 42a. The upper wall of the shift casing 40 defines a guide groove 41 to guide the travel of the shift lever 42 between a forward, neutral and reverse position. A base end portion 44 of the shift lever 42 is designed either as shown in Figure 6 pivotable about a shaft 45 in a shift casing 40 or is designed as shown in Figure 8a connected through a ball joint to a supporting boss portion 72 of the shift casing 40 both modes allowing the shift lever 42 to be swung in the directions of the arrows A longitudinally and B transversely as indicated in Figure 9a. The supporting boss portion 72 is reinforced by case ribs 71 and an end of the shift cable 43 is connected to the shift lever 42 near its base end portion 44. As will be apparent when the description proceeds the design of the guide groove 41 is responsible for a certain time lag to occur when performing a shifting operation from the forward running condition to the reverse running condition preventing immediate single straight stroke shift actuation of the shift lever 42. As shown in Figures 7, 8, 10a and a plurality of further Figures the guide groove 41 has a first straight groove portion 41a connecting the forward position F and the neutral position N and the laterally offset guide groove 41c leading to the reverse position R with a groove step portion 41b connecting the straight and offset groove portions 41a, 41c and, moreover, connecting the neutral position N to the reverse position R. Thus, the guide 41 provide a straight groove portion 41a for the forward and neutral positions F, N and a laterally offset guide groove portion 41c for the reverse position, both groove portions 41a, 41c being connected through the step portion 41b and, accordingly, the guide groove in total has a general Z-shaped configuration. Thus, the forward position F defined at the end of the first straight groove portion 41a and the reverse position defined at the end of the laterally offset groove portion 41c are staggered from each other and, accordingly, the guide groove 41 forms a regulating means for preventing shift lever 42 from being moved straight ahead in a single straight stroke movement from a forward state to a reverse state and the shift operation requires a certain time and, therefore, a substantial shock resulting from the changeover from the forward to a backward planing can be avoided. As is apparent from Figures 8 and 10a the first portion 41a of the guide groove 41 does not only connect the forward position F and the neutral position N but extends also to a speed reduction position S (see also Figure 10d), said position S being provided at a transitional area from the straight groove portion 41a to the step portion 41b. Of course, it would also be possible to define this position as the neutral position transferring the speed reduction position to an another downstream locus. With the afore-indicated structure, the reverse gate 27 is shifted to the forward state (see Figure 10b) by moving the shift lever 42 to the forward position F shown in solid lines in Figure 9a, thus propelling the boat forward by the water jet ejected from the jet nozzle 26 rearward or is deflected sideward to drive the boat along a curve. In case of opening the engine throttle fully setting the throttle lever 22 in its froward position the boat driven forward at full speed. In order to break or reverse the boat running in the full speed condition the shift lever 42 is pulled rearward from the forward position F shown in Figures 8 (in phantom line), Figure 9a (in solid line) and Figures 10a, 10b in the direction of arrow A along the first guide groove portion 41a. By this operation the shift lever 42 passes the neutral position N shown in Figure 8 (in solid lines) and Figure 10c, reaches the speed reducing position S, Figure 8 (in phantom line) and Figure 10d at the step portion 41b and is once stopped in that position. Then, after the shift handle 42 is transferred in the sense of the arrow B from the position S it is pulled transversely with respect to the direction of arrow A and then along the laterally offset guide groove portion 41c to reach the reverse position R. By means of this operation the reverse gate 27 is rotated about the shaft 28 through the shift cable 43 to be shifted to the position opposite to the jet opening of the jet nozzle 26 as shown in Figures 9b and 10e. The water jet from the jet nozzle 26 is reverse to exert a rearward propelling force on the boat body 10 resulting in a great breaking force. In the forward state shown in Figure 10b the water jet ejected from the jet nozzle 26 is a 100% ejected rearward, is ejected downward in the neutral state shown in Figure 10c, is 20 to 50% ejected forward in the speed reducing state S shown in Figure 10d and is a 100% ejected forward in the reverse state shown 10e. Thus, although the direction of the propelling force is changed from forwards to rearwards when the shift lever 42 is moved to the reverse position R while running the boat forward the directional change of the propelling force occurs smoothly preventing a abrupt change of the direction of the propelling force since the shift lever 4 is once stopped near the neutral position N (preferably in a speed reducing position S) while travelling from the forward position F to the reverse position R. Thus, an excessive speed reducing force will not be exerted on the boat and the crew members therein. Moreover, as already indicated above, a switch 60 is actuated to energize indicators 31 thus informing other boats running behind from the speed reduction initiated. In the following the preferred disposal of the first acutating means comprising the shift levers 42 for shifting the direction of the force propelling the boat and the second actuating means comprising the throttle levers 22 for adjusting the engine throttle is explained referring to several embodiments as exemplified in Figures 11 to 19. As shown in Figure 7 the shift casing 40 with the shift levers 42 can be disposed in front of the throttle casing 21 with the throttle levers 22 moveable in the longitudinal direction of the boat aside of a driver's seat to be conveniently operated by the boat's driver. In order to allow the throttle lever 22 to be actuated immediately after the shift lever 42 was shifted into the reverse position R or the speed reducing position S the hand grip 42a of the shift lever 42 put in the reverse position R should be located closely adjacent to the hand grip 22a of the throttle lever 22 put in the open position (full forward speed). Accordingly, the embodiment of Figures 7 and 11 indicate the throttle casing 21 to be disposed straight ahead behind the shift casing 40 operating both levers 42, 22 in the same longitudinal direction. As shown in Figure 11, when the shift lever 42 has been pulled rearward to the reverse position R by the driver's hand 100 while the throttle lever 22 rests in the fully open (full throttle) position the hand grip 22a of the throttle lever 22 positioned just behind the shift lever 42 can be gripped operated to adjust the breaking force to an appropriate value. Accordingly, while a breaking force can be rapidly exerted on the boat by acutating the reverse gate 27 during full speed running by operating the shift lever 42 the throttle lever 22 can be gripped without any delay and rapidly operated as well so that the breaking force is adjustable to an appropriate magnitude and quick operation is possible as the throttle lever 22 is positioned very close to the shift 42 after the shifting operation is terminated and, the hand grip 22a can be rapidly gripped. Thus, the hand 100 moves straightly from the pivot position to the reverse position together with the shift lever 42 and then moves continually in the same direction to operate the throttle lever 22 leading to a train of operations being rapidly and smoothly performed. Thus, while a great breaking force is immediately obtained during full speed running the magnitude of the breaking can be reliably adjusted in order to assure that the crew members are not subject to greater shocks resulting from an excessive breaking force. Other appropriate embodiments of the disposal of the shift and throttle casings 40, 21 and associated levers 42, 22 are explained in the following referring to Figures 12 to 19. Figures 12 and 13 show another schematic plane and side views of the driver's seat area of the boat with driver's seat being omitted. In order to better meet the requirements of human engineering the throttle casing 21 is laterally offset outwardly with respect to the shift casing 40 in front of the throttle casing. In this way the grip 42a of the shift lever 42 set in the reverse condition and the grip 22a of the throttle lever 22 in the full throttle position overlap in side view, as shown in Figure 13. In the case, preferably, the height of the grips 42a, 22a of the shift levers 42 in the rearward position and of the throttle levers 22 in the full throttle forward position is approximately the same thus facilitating quick operation of both lever arrangements. The embodiment according to Figures 14 and 15 is slightly different from the afore-described one in that a notional extension E of the innermost throttle lever 22 runs between the pair of shift levers 22 ahead which renders narrow the total width W of both pairs of levers 42, 22. Moreover, a distance T is left to provide a space for the fingers of the operators head 100 allowing to insert the fingers between the grips 42a, 22a of the shift levers 42 being the reverse position and the throttle levers 22 being in the full throttle position inclined forwardly. Another embodiment of lever disposal is shown in Figure 16 wherein the height of the grip 42a of the shift lever 42 in the rearward position is different (upper or lower) than that of the grip 22a of the throttle lever 22 put in the full throttle forward position. Figure 17 refers to an embodiment wherein the deck portion 10a of the boat is designed to have a upwardly inclined slope portion with the shift casing 40 being installed at said slope portion. Due to this arrangement a range L of lever movements of both of shift and throttle levers 42, 22 becomes relatively short. Figures 18 and 19 disclose yet another embodiment of disposing the shift and throttle casings 40, 21. In this case the throttle casing and, accordingly, the throttle lever 22 is disposed in front of the shift casing 40 and the associated shift lever 42. In its further aspects this embodiment substantially corresponds to those of Figures 12 and 13. As is apparent from the plane view of this embodiment shown in Figure 19 in this case it can be more convenient to assure smooth operation from the driver's seat to modify the layout of the guide groove 41 in such a manner the shift lever 42 is moved laterally outwardly during its travel from the front position F to the reverse position R. It should be readily apparent that generally the pair of hand grips 42a and 22a of the shift and throttle levers 42, 22 is gripped and actuated jointly operating both engines 23 and associated jet units 24 (more specifically the reverse gates 27) simultaneously and synchronously. However, each lever 42, 22 of the paired levers 42, 22 can also be operated separately, if desirable. By actuating the paired shift levers 42 and the paired throttle levers 22 separately, specifically by controlling one of the left or right engines 23 and only one of the reverse gates, the boat can be turned quickly and superior manoeuvrability can be provided.

Claims: A water jet propulsion boat comprising an engine powered jet unit (24) having a pair of jet nozzles (26) and a reverse gate (27) hingedly connected to said jet nozzles (26) in order to deflect the water jet ejected from the jet nozzles (26), and first and second actuating means for changing the position of the reverse gate (27) with respect to a jet opening of the jet nozzle (26) and for controlling the throttling action of an engine for adjusting the performance thereof, wherein the first actuating means comprises a pair of shift handles (42) which are shiftable at least between forward and reverse positions (F, R), wherein a guide means (41) for controlling the travel of the shift handles (42) between said positions (F, R) is provided preventing the shift handle (42) from being shiftable between the forward and rearward positions (F, R) by a straight single stroke, characterized in that a boat drive system comprises a pair of engines (23) driving a pair of jet units (24), the second actuating means comprises a pair of throttle levers (22) and together with the first actuating means enabling to operate each drive train composed of an engine/jet unit arrangement separately, and that casings (40, 21) of the shift and throttle actuating means accommodating the associated shift and throttle levers (42, 22) are disposed in alignment to each other with the throttle lever (22) disposed behind the shift lever (42) in the direction of shift lever operation, and that the shift and throttle levers (42, 22) are disposed such that the throttle lever (22) in its fully opened position is disposed just behind the shift lever (42) set in its reverse position, both levers (42, 22) being operated in the longitudinal direction of the boat. A water jet propulsion boat as claimed in claim 1, characterized in that , the shift handle is a shift lever (42) swingably supported through a ball joint disposed in a shift casing (40) which, in turn, defines a guide groove (41) for guiding the travel of the shift lever (42) between said forward, neutral and reverse positions (F, N, R), said guide groove (41) comprising a straight portion (41a) connecting the forward and neutral positions (F, N) and an offset portion (41c) connecting the neutral and reverse positions (N, R), with a step portion (41b) between the straight and offset portions (41a, 41c) preferably defining a speed reducing position (S). A water jet propulsion boat as claimed in claim 2, characterized in that , the guide groove (41) substantially has a Z-shaped configuration providing a corresponding travelling path of the shift lever (42). A water jet propulsion boat as claimed in claims 1 or 3, characterized in that , an upper end portion of the shift lever forms a grip (42a, 22a) disposed above the shift casing (40). A water jet propulsion boat as claimed in at least one of the preceding claims 1 to 4, characterized in that , the first and second actuating means are shift and throttle actuating means which are disposed at the body (10) of the boat adjacent to each other. A water jet propulsion boat as claimed in at least one of the preceding claims 1 to 5, characterized in that , the throttle actuating means comprises a pair of throttle levers (22) disposed behind the pair of shift levers (42) in the longitudinal direction of the boat, both types of levers (42, 22) being installed near the driver's seat. A water jet propulsion boat as claimed in at least one of the preceding claims 1 to 6, characterized in that , the throttle casing (21) with the throttle levers (22) is laterally offset outwardly with respect to the shift casing (40) disposed in front of the throttle casing (21). A water jet propulsion boat as claimed in at least one of the preceding claims 1 to 7, characterized in that , the grips (42a, 22a) of the shift and throttle levers (42, 22) are disposed at about the same height when the shift lever (42) is in its reverse position and the throttle lever (22) is in its fully open position. A water jet propulsion boat as claimed in at least one of the preceding claims 1 to 8, characterized in that , a reverse state indicating means (31) is installed on the stern of the boat. A water jet propulsion boat as claimed in claim 9, characterized in that , a switch means (60, 61) is provided to actuate the reverse state indicating means (31) in response to an actuation of the shift lever (42) towards its reverse position. A water jet propulsion boat as claimed in claim 10, characterized in that , the switch (60, 61)is actuated in response to a movement of the shift lever (42) or the reverse gate (27), respectively.

Inventors: FUTAKI YOSHIKI, KOBAYASHI NOBORU, KOYANAGI TOMOYOSHI, FUTAKI, YOSHIKI, KOBAYASHI, NOBORU, KOYANAGI, TOMOYOSHI
Applicants: YAMAHA MOTOR CO LTD, YAMAHA HATSUDOKI KABUSHIKI KAISHA
Application year: 1991
Main classification: B63H21
IPC codes: B63H11, B63H21, B63H25