Abstract:
A tiller handle assembly for an outboard motor is provided that comprises a steering handle having a generally hollow body. A throttle grip is attached to a front end of the steering handle, and a shift mechanism coupled to the steering handle. The shift mechanism includes an moveable operator that can be moved at least between two positions: one of the positions corresponding to a drive operational mode of the outboard motor and the other position corresponding to a neutral operational mode of the outboard motor. A sensor device is disposed within the hollow body of the steering handle and is configured to determine whether the movable operator is positioned in one of the two position. The location of the sensor device within the hollow body makes mounting and maintenance of the sensor device easier and generally isolates the sensor device from water.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application is based on claims priority under 35 U.S.C. § 119(a)-(d) to Japanese Patent Application No. 2004-172428, filed on Jun. 10, 2004, the entire contents of which is expressly incorporated by reference herein.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a tiller handle assembly for operating an outboard motor, and more specifically to a tiller handle assembly for an outboard motor having a neutral switch mounted inside.  
         [0004]     2. Description of the Related Art  
         [0005]     Japanese Patent Publication No. Hei 10-218088 discloses an outboard motor with an engine, which is conventionally mounted to the stem of a small boat. Steering the watercraft is typically accomplished by turning the outboard motor. To control movement of the outboard motor, the watercraft can include a steering wheel and/or a the outboard motor can include a tiller arm. The steering wheel is usually positioned in front of the operator&#39;s seat, and the tiller arm has a rod shape that is directly connected to the outboard motor. An operator operates the steering wheel or tiller arm to cause the outboard motor to swing toward the port or starboard sides to change the direction in which the boat moves.  
         [0006]     Controlling functions such as shifting and accelerating are commonly accomplished by either a remote controller or by controls located on the tiller arm of the outboard motor. The tiller arm extends from the outboard motor, while the remote controller is disposed near an operator&#39;s seat (usually at a side of the operator&#39;s seat) in the boat. The controls, which are disposed at either of these locations, commonly include an operator to shift the outboard motor among operational modes (e.g., forward, neutral, and reverse) and an operator to control engine speed (and hence the propulsion thrust). In some applications, these operators are combined together (e.g., a single lever on a remote control unit).  
         [0007]     In applications that use a shift lever, the shift lever is pivoted forward from a neutral position to a forward position to engage the engine with the propeller and to cause the propeller to rotate in a direction propelling the boat forward. To propeller the boat in reverse, the shift lever is pivoted rearward from the neutral position to a reverse position to engage the engine with the propeller and to cause the propeller to rotate in an opposite direction.  
         [0008]     In this type of small boat, a neutral switch is commonly used to prevent starting the engine when the shift lever is at its forward or reverse position. The neutral switch detects the position of the shift lever and allows a start motor of the engine to operate only when the shift lever is at its neutral position. In the case of an outboard motor in which shift control of the engine is accomplished by a remote control (shift lever) at a side of the operator&#39;s seat away from the stem, the neutral switch is usually disposed in a remote controller. In applications where a tiller arm is used, the neutral switch is disposed within a cowling of the outboard motor.  
         [0009]     Japanese Patent Publication No. 200-272588 discloses an example of a tiller handle assembly for an outboard motor. The tiller handle assembly is attached to the outboard motor depending on user&#39;s needs. The outboard motor is rotated about a swivel shaft for steering with such tiller handle assembly. The tiller handle assembly has a steering handle body of a rod shape that is pivotally connected to the outboard motor and extends generally horizontally toward the inside of the boat. A throttle grip is attached to the front end of the steering handle body and is rotatable about its axis. Turning the throttle grip about the axis of the steering handle body controls opening and closing of a throttle valve and, hence, engine speed. Additionally, a shift lever, as described above, is attached to the tiller handle assembly.  
         [0010]     As noted above, in applications employing a tiller handle assembly with a shift lever, the neutral switch is conventionally mounted to a shift mechanism located in the cowling of the outboard motor. Because the exact application of the outboard motor is not known at the time of its assembly, the tiller handle assembly is usually attached after the outboard motor has been shipped from the manufacturers factor. Accordingly, an after-factory worker (e.g., a dealer mechanic) typically installs the neutral switch within the outboard motor cowling.  
         [0011]     Mounting the neutral switch to the outboard motor later and then wiring, however, is very complicated and troublesome work. Further, since the neutral switch is mounted to the completed outboard motor shipped from a plant, by a distributor or a user, mounting quality is less uniform than would it be if assembled during the production processes at the plant. Furthermore, the neutral switch mounted to the outboard motor has a different configuration from the neutral switch disposed in the remote control. This requires two types of neutral switches: one type for the remote control and one type for the outboard motor.  
         [0012]     Additionally, because the outboard motor cowling is provided with an air intake for drawing air into the engine, some water typically enters inside of the outboard motor cowling. Thus, to mount the neutral switch in the outboard motor, the switch is required to be waterproof, resulting in a complicated structure and cost increase. In particular, a shift link mechanism, which is used to shift the operational mode of the outboard motor among forward, reverse, and neutral modes, is located at a lower portion in the cowling. Thus, the neutral switch for detecting the neutral position through operation of the shift link mechanism is also located adjacent to the shift link mechanism at the lower portion in the cowling. Water, which enters the inside of the cowling, tends to collect at the lower portion in the cowling. This requires a waterproof configuration, such as making the neutral switch itself waterproof or covering it with a waterproof cover. Either approach, however, increases cost and complicates the retrofit of the neutral switch onto the outboard motor.  
         [0013]     A need therefore exists for an improved neutral switch for use a tiller handle assembly.  
       SUMMARY OF THE INVENTION  
       [0014]     An aspect of the present invention involves a tiller handle assembly for an outboard motor that comprises an elongated steering handle having a longitudinal axis. The steering handle is configured to be pivotally connected to the outboard motor and to extend outward from the outboard motor. A throttle grip attaches to a front end of the steering handle and is rotatable generally about the longitudinal axis. A movable shift lever is provided to select an operational mode of the outboard motor among forward, neutral and reverse operational modes, and a neutral switch is disposed inside the steering handle. The neutral switch is arranged to determine at least when the shift lever lies in a position corresponding to the neutral operational mode for the outboard motor.  
         [0015]     There are several advantages associated with locating the neutral switch within the steering handle body. If a purchaser elects to purchase an outboard motor with a tiller handle, an after-factory worker (e.g., a mechanic for a dealer) need not mount the neutral switch in the outboard motor. Therefore, quality in assembling and wiring of the neutral switch becomes consistent, and its reliability increases. Further, because the tiller handle is disposed inside the boat, there is a reduced chance of water entering the steering handle body in comparison to the outboard motor cowling. Thus, the enhanced water isolation improves the durability of the switch.  
         [0016]     An additional aspect of the present invention involves a tiller handle assembly for an outboard motor that comprises a steering handle having a generally hollow body. A throttle grip is attached to a front end of the steering handle, and a shift mechanism coupled to the steering handle. The shift mechanism includes an moveable operator that can be moved at least between two positions: one of the positions corresponding to a drive operational mode of the outboard motor and the other position corresponding to a neutral operational mode of the outboard motor. A sensor device is disposed within the hollow body of the steering handle and is configured to determine whether the movable operator is positioned in one of the two position. The location of the sensor device within the hollow body makes mounting and maintenance of the sensor device easier and generally isolates the sensor device from water.  
         [0017]     While certain aspects, features and advantages of the tiller handle assembly have been noted above, various embodiments of such need not provide all of the above-noted advantages and features. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     The preferred embodiment of the present tiller handle assembly for outboard motor, illustrating its features, will now be discussed in detail. This embodiment depicts the novel and non-obvious tiller handle assembly shown in the accompanying drawings, which are for illustrative purposes only. These drawings include the following figures, in which like numerals indicate like parts:  
         [0019]      FIG. 1  is a side elevational view of an outboard motor with a tiller handle assembly configured in accordance with the preferred embodiment of the invention, with several internal components of the outboard motor shown in phantom;  
         [0020]      FIG. 2  is an enlarged top plan view of the tiller handle assembly of  FIG. 1 ;  
         [0021]      FIG. 3  is a cross-sectional view of the tiller handle assembly of  FIG. 1  as viewed from the side;  
         [0022]     FIGS.  4 (A) and  4 (B) are enlarged views of the area within circle C shown in  FIG. 3 , with a shift lever moved between a drive position and a neutral position, respectively;  
         [0023]      FIG. 5  is an enlarged cross-sectional view of the tiller handle assembly taken along the line D-D in  FIG. 3  and [ FIG. 6  is a circuit diagram incorporating a neutral switch of the present embodiment. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0024]      FIG. 1  shows the overall configuration of an outboard motor  2  and a tiller handle assembly  1  according to the preferred embodiment of the present invention.  
         [0025]     From top to bottom, the outboard motor  2  includes a propulsion device (e.g., an internal combustion engine) covered by an upper cowling  21 , a lower cowling  22 , an upper casing  23 , and a lower casing  24 . The outboard motor  2  is mounted to a transom plate  91  of a hull  9  through a clamp bracket  20 .  
         [0026]     A four-stroke engine  31 , for example, is housed inside the upper cowling  21  and the lower cowling  22 . Of course, the present tiller handle assembly  1  can be used with outboard motors having other types of engines that operate on other types of combustion principles. The illustrated engine  31  has a crankshaft (not shown) disposed in a direction generally perpendicular to the surface of water (i.e., generally vertically oriented). The crankshaft is connected to the upper end of a drive shaft  32 . The drive shaft  32  vertically extends in the upper casing  23  and the lower casing  24 , and its lower end is connected to a transmission or forward-reverse shifting gear mechanism  33 , which includes a pair of counter-rotating forward and reverse bevel gears and a dog clutch. These gears and clutch are housed in the lower casing  24 . A propeller shaft  34  extends horizontally from the gear mechanism  33 . The gear mechanism  33  transmits rotational force from the drive shaft  32  about its vertical axis to the propeller shaft  34  through either of the forward and reverse bevel gears, after converting it to rotational force about a horizontal axis of the propeller shaft  34 . A propeller  35  is mounted to an end of the propeller shaft  34  which projects outside the lower casing  24 . Rotation of the propeller  35  underwater propels the hull  9 .  
         [0027]     In addition, the gear mechanism  33  is configured to change the rotational direction of the propeller shaft  34  in accordance with operation of a shift rod  36  so that the moving direction of the hull  9  changes between forward and reverse directions.  
         [0028]     The outboard motor  2  itself is mounted onto the transom plate  91  in a manner that permits rotation of the outboard motor  2  about a tilt shaft  29  through a hydraulic mechanism, for example. This allows the operator to increase a tilt angle of the outboard motor  2  to lift it above the surface of water for docking and to adjust a trim angle of the outboard motor  2  to obtain optimum propelling force during operation of the boat.  
         [0029]     The tiller handle assembly  1  generally has a rod-like shape and is attached to the outboard motor  2  through a steering bracket  10 . The tiller handle assembly  1  extends generally horizontally toward the inside of the hull  9 . The base end of the tiller handle assembly  1  is connected to the steering bracket  10  through a pivot shaft  19 . This allows rotation of the tiller handle assembly  1  upward relative to the steering bracket  10 , as indicated by the arrow A in  FIG. 1 .  
         [0030]     The tiller handle assembly  1  has a throttle grip  12  disposed at its front end, and a shift lever  15  disposed rearward from the throttle grip  12 . The throttle grip  12  preferably is connected to an intake system  101 , including a throttle valve (not shown), of the engine  31  through a throttle cable  42 , as described later. In other embodiments, however, the throttle grip  12  can interact with other components of the engine to vary the propulsion speed of the outboard motor  2 .  
         [0031]     The shift lever  15  is attached to a rotational shaft  54 , at its base, to rotate forward and rearward. When the shift lever  15  is at its central position, a neutral mode (N) is selected. When it is tilted forward and rearward, modes of a transmission are shifted to a forward mode (F) and a reverse mode (R), respectively. The shift lever  15  is connected to a link mechanism  102  in the outboard motor  2  through a shift cable  51 , as described later. The link mechanism  102 , through the shift rod  36 , causes the dog clutch to engage with one of the paired bevel gears of the gear mechanism  33  through the shift rod  36 . The engagement of the dog with the bevel gear couples together the propeller shaft and the drive shaft, causing the propeller shaft to rotate in either a forward or reverse mode, depending upon which bevel gear is engaged.  
         [0032]     With reference to  FIG. 2 , the tiller handle assembly  1  has a steering handle body  11  of a rod-shaped, aluminum alloy casting or the like. The accelerator throttle grip  12  for opening and closing the throttle valve (not shown) of the intake system of the engine is mounted to the front end of the steering handle body  11  and is rotatably about its axis C 2 .  
         [0033]     In the illustrated embodiment, the axis C 2  of the steering handle body  11  is inclined to the port side with respect to the central axis Cl of the outboard motor  2 , as seen in  FIG. 2 . The operator usually steers with the outboard motor  2  behind him/her while holding the throttle grip  12  of the tiller handle assembly  1  with his/her left hand. The steering handle body  11  can of course be angled toward the starboard side in other applications.  
         [0034]     The throttle grip  12  preferably is a plastic or rubber member and is formed with recesses and projections (e.g., ribs) on its surface as appropriate to increase friction applied to an operator&#39;s palm so that his/her hand is inhibited from slipping off the grip.  
         [0035]     The shift lever  15  is positioned at the tiller handle assembly  1  rearward from the throttle grip  12 , namely, closer to the outboard motor  2  than the throttle grip  12 . The operator selects any of forward, reverse, and neutral modes with the shift lever  15 .  
         [0036]     The steering handle body  11  is provided with various switches such as a throttle friction device  13  for regulating friction exerted on the throttle grip  12 , a power tilt and trim switch (not shown) used for adjusting a tilt angle and a trim angle of the outboard motor  2 , an idle speed control switch  14 , a main switch  16  for turning the main power on/off, and a lanyard switch  17  for forcibly stopping the engine. A lanyard  4 , to connect to an operator&#39;s arm or the like, is attached to the lanyard switch  17 , as shown in  FIG. 1 . Incidentally, the idle speed control switch  14  and the main switch  16  are not shown in  FIG. 1 .  
         [0037]     The base end of the tiller handle assembly I is formed with a cable lead-out opening  40 . Various cables including the throttle cable  42  and the shift cable  51  are led out from the cable lead-out opening  40  into a cable lead-in opening  30  formed at the front end of the lower cowling  22  ( FIG. 1 ).  
         [0038]      FIG. 3  shows an inside structure of the tiller handle assembly  1 . In this preferred embodiment, the steering handle body  11  is made up of an upper casing  11   a  and a lower casing  11   b  that together form an outside casing of the tiller handle assembly  1 . The steering handle body  11  is formed as an aluminum alloy casting, for example. The inside of the steering handle body  11 , which is surrounded by the upper casing  11   a  and the lower casing  11   b , accommodates the throttle cable  42 , the shift cable  51 , lead wires for various switches, and the like.  
         [0039]     The throttle grip  12  is connected to the front end of a throttle shaft  41  with a screw  49 . Thus, when the throttle grip  12  is turned, the throttle shaft  41  turns together with the throttle grip  12 .  
         [0040]     A portion of the throttle shaft  41  close to its front end is retained by a retaining portion  48 , and a spring  47 , which is for urging the throttle shaft  41  in a certain direction, is located between the retaining portion  48  and a plate  46 . When the throttle shaft  41  turns, a moving member  43  at an end of the throttle shaft  41  turns a turning support member  44  about its shaft  44 a. This moves the throttle cable  42 , which preferably is in the form of a push-pull cable, longitudinally as indicated by the arrow B. In such manner, rotation of the throttle shaft  41  is transmitted to the throttle cable  42  as longitudinal movement, which in turn opens and closes the throttle valve (not shown) of the intake system of the engine  31  mounted in the outboard motor  2  shown in  FIG. 1 . This regulates the volume of air intake and thus controls the output of the engine.  
         [0041]     The shift lever  15  is attached rotatably in both the forward and rearward directions and moves relative to the steering handle body  11 . The shift lever  15  and the front end of the shift cable  51  are connected through a shift transmission mechanism  52 .  
         [0042]     The shift transmission mechanism  52  includes a connection linkage  53  and the rotational shaft  54 . The shift lever  15  at its base end is attached to or integrated with the rotational shaft  54  and rotates about the rotational shaft  54  within a specified range of motion so that the transmission is shifted among the forward, reverse, and neutral operational modes, as described above in connection with  FIG. 1 . The connection linkage  53  is attached to the rotational shaft  54 , and the front end of the shift cable  51 , which preferably is a push-pull cable, is connected to the connection linkage  53 .  
         [0043]     Operating the shift lever  15  causes the shift transmission mechanism  52  to longitudinally move the front end of the shift cable  51 . The shift cable  51  is routed into the cable lead-in opening  30  ( FIG. 2 ) of the outboard motor  2  from the cable lead-out opening  40  of the rear end of the tiller handle assembly  1  and is connected to the link mechanism  102  at the upper end of the shift rod  36  in the outboard motor  2  shown in  FIG. 1 . In the illustrated embodiment, when the shift lever  15  is moved forward, the boat is propelled forward, while when the shift lever  15  is moved rearward, the boat is propelled rearward. When the shift lever  15  is directed upward, a neutral operational mode is selected.  
         [0044]     The inside of the steering handle body  11  is provided with a neutral switch  6 . In the illustrated embodiment, the neutral switch  6  includes a switch body  61  with a switch button  62  ( FIG. 4 ), and a cam  63  that functions as an actuator to depress the switch button  62  to actuate the switch. The neutral switch  6  preferably is located below the throttle shaft  41 , which is provided generally within the center of the tiller handle assembly  1 . The cam  63  is mounted to the rotational shaft  54  of the shift lever  15  and rotates about the rotational shaft  54  together with the shift lever  15 . The switch body  61  is positioned rearward from the cam  63 , namely, closer to the cable lead-out opening  40  than is the cam  63 . The switch button  62  of the switch body  61  ( FIG. 4 ) is disposed below the center of the rotational shaft  54  of the shift lever  15 .  
         [0045]     FIGS.  4 (A) and  4 (B) are explanatory views of operation of the neutral switch in accordance with the illustrated embodiment.  
         [0046]     When the shift lever  15  is moved forward to its forward position, the cam  63  rotates counterclockwise about the rotational shaft  54 , and thus a projection  64  of the cam  63  moves upward away from the switch button  62  of the switch body  61 , so that the switch button  62  is not depressed, as shown in  FIG. 4 (A). That is, the neutral switch is not actuated (e.g., turned off). Similarly, when the shift lever  15  is moved to its reverse position, the cam  63  rotates clockwise about the rotational shaft  54 , and thus the projection  64  of the cam  63  moves downward away from the switch button  62 . Thus, the neutral switch is not actuated.  
         [0047]     When the shift lever  15  is at its neutral position, the projection  64  depresses the switch button  62 , as shown in  FIG. 4 (B), so that the neutral switch  6  is actuated (e.g., turned on).  
         [0048]     Since the cam  63  has a turning axis coaxial with a turning axis of the shift lever  15  and rotates in connection with the shift lever  15 , the cam  63  can correctly indicate the neutral position of the shift lever  15  correspondingly to operator&#39;s operation of the shift lever  15 .  
         [0049]     The neutral switch  6  is located rearward from the rotational shaft of the shift lever  54 , namely, closer to the base end of the steering handle body  11  at which it is connected to the outboard motor  2 . This makes a lead wire for the neutral switch  6  relatively short, thereby preventing complicated wiring. Further, since no lead wire runs by the rotational shaft  54  of the shift lever  15 , the lead wire does not interfere with the rotation of the shift lever  15 . This ensures reliable shift operations and reduces damage and deterioration of the lead wire.  
         [0050]     As best seen in  FIG. 5 , which is a sectional view of the tiller handle assembly, the steering handle body  11  is made up of the upper casing  11   a  of an inverted squared U-shape in section with a downward opening, and the lower casing  11   b  to cover the downward opening of the upper casing  11   a . The assembly of the upper and lower casings  11   a ,  11   b  produces a tubular structure; however, the steering handle body can have other configurations with one or more hollows to house at least the neutral switch.  
         [0051]     The shift lever  15  is attached to the rotational shaft  54 . The connection linkage  53  and the cam  63  are also attached to the rotational shaft  54 . The upper end of the connection linkage  53  is connected to an end of the shift cable  51 , as best seen in  FIG. 3 .  
         [0052]     As also seen in  FIG. 3 , the neutral switch  6  is disposed along the longitudinal direction of the steering handle body  11 , below the throttle shaft  41 , which is provided generally at the center within the steering handle body  11 . Thus, adjustment to the cam  63  and to the neutral switch  6  can be easily made. The tiller handle assembly  1  simply is rotated about the shaft  19  as indicated by the arrow A ( FIG. 1 ), and the lower casing  11   b  of the steering handle body  11  is removed from the upper casing  11   a  to expose these components of the tiller handle assembly  1 . As such, maintenance is made easy because the neutral switch is positioned in front of a worker once the lower casing is removed from the upper casing after rotating the steering handle body upward. In addition, since the tiller handle assembly is located inside the boat, the operator can adjust the neutral switch on the water as well.  
         [0053]      FIG. 6  illustrates a circuit diagram for a starter motor of the engine, which includes the neutral switch  6 . In the illustrated embodiment, the neutral switch  6  is connected to the main switch  16  and a starter relay  73  in series. A battery  71  is connected to the main switch  16 , the neutral switch  6 , and the starter relay  73  through a fuse  72 , in series. The starter relay  73  is connected to a starter motor  74  through a relay circuit  74   a . This exemplary circuit configuration allows the supply of power to the starter motor  74  from the battery  71  to run the starter motor  74 , only when the shift lever  15  is at its neutral position and the neutral switch  6  is actuated. In a more particular embodiment, power, which is supplied from the battery  71  when the main switch  16  is turned on and the neutral switch  6  is in an ON state (a neutral mode is selected), activates the starter relay  73  through the fuse  72  to start the starter motor  74 . Since the neutral switch  6  is not activated when the shift lever  15  is at its forward or reverse position, the starter relay  73  is not activated and thus the starter motor  74  does not start.  
         [0054]     Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. For example, the cam can be shaped so as to actuate the switch when the shift lever is located at a position other than its neutral position and the absence of a signal from the neutral switch can be used to complete the starter motor circuit. Additionally, other types of sensors and switches can also be used in place of the above-described micro switch to determine the position of the shift lever, such as, for example, but without limitation, potentiometers, Hall-effect switches and the like.  
         [0055]     While a number of variations of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or subcombinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims.