Patent Document

BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an outboard motor and a hook assembly used for the outboard motor. 
     2. Description of the Related Art 
     Conventionally, various methods of fixing a bottom cowling and a top cowling have been disclosed. For example, in JP-A-Hei 2-141390, a method for fixing the bottom cowling and the top cowling together using a hook member is proposed. 
     During traveling of a boat, there could be a case in which an obstacle such as a standing timber collides with an outboard motor. When the obstacle collides with the outboard motor during the traveling of the boat, an outboard motor body is lifted up, so that a force is applied between the top cowling and the bottom cowling in a direction such that the top cowling and the bottom cowling approach each other. This compresses a seal member disposed between the top cowling and the bottom cowling. As a result, the distance between the top cowling and the bottom cowling is shortened. Moreover, an inertia force is generated on a lever arranged to operate a hook member. Consequently, a mere fixing of the bottom cowling and the top cowling via the hook member could cause a rotation of the hook member and could cause the lever to disengage the hook member when the obstacle collides with the outboard motor during the traveling of the boat. 
     For example, providing a biasing member for urging the hook member in the direction of the engaged state is included as a method to prevent the cancellation of the engaged state of the hook member when the obstacle collides with the outboard motor during the traveling of the boat. 
     However, by providing the biasing member, a great deal of power is consequently required to operate the lever, which tends to lower the operability of the lever. 
     SUMMARY OF THE INVENTION 
     In order to overcome the problems described above, preferred embodiments of the present invention provide a hook assembly for an outboard motor with high operability that prevents the cancellation of an engaged state even when an obstacle collides with the outboard motor during traveling of a boat. 
     An outboard motor according to a preferred embodiment of the present invention includes a first housing, a second housing, an elastic member, and a hook assembly. The second housing is mounted on the first housing. The second housing includes an engaged member. The elastic member is disposed between the first housing and the second housing. The hook assembly is provided on the first housing. The hook assembly engages with the engaged member to mutually fix the first housing and the second housing. The hook assembly preferably includes a rotation shaft, a hook member, a lever, and a rotation regulating member. The rotation shaft is rotatably mounted on the first housing. The hook member is fixed to the rotation shaft. A recessed portion is provided in the hook member. The recessed portion opens in a first rotation direction. The recessed portion engages with the engaged member. The lever is fixed to the rotation shaft. The lever extends from the rotation shaft in a second rotation direction that is opposite to the first rotation direction of the recessed portion. The rotation regulating member regulates the rotation of the hook member in the second rotation direction when the hook member and the engaged member are engaged with one another. 
     A hook assembly according to a preferred embodiment of the present invention relates to a hook assembly which is mounted on a first housing of an outboard motor that includes the first housing, a second housing mounted on the first housing and having an engaged member, and an elastic member disposed between the first housing and the second housing such that it engages with the engaged member to mutually fix the first housing and the second housing together. 
     The hook assembly according to a preferred embodiment of the present invention preferably includes a rotation shaft, a hook member, a lever, and a rotation regulating member. The rotation shaft is rotatably mounted on the first housing. The hook member is fixed on the rotation shaft. A recessed portion is provided in the hook member. The recessed portion opens in a first rotation direction and engages with the engaged member. The lever is fixed on the rotation shaft. The lever extends from the rotation shaft in a second rotation direction opposite to the first rotation direction of the recessed portion. The rotation regulating member regulates the rotation of the hook member in the second rotation direction in a state in which the hook member and the engaged member are engaged with one another. 
     According to a preferred embodiment of the present invention, it is possible to provide a hook assembly for an outboard motor having high operability and preventing a disengaged state even when an obstacle collides with the outboard motor during traveling of a boat. 
     Other features, elements, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a left side view of an outboard motor according to a preferred embodiment of the present invention. 
         FIG. 2  is a rear view of a top cowling and a bottom cowling in an engaged state. 
         FIG. 3  is a rear view of the top cowling and the bottom cowling in a disengaged state. 
         FIG. 4  is a bottom view of the top cowling. 
         FIG. 5  is a plan view of the bottom cowling. 
         FIG. 6  is a partially enlarged plan view of the bottom cowling. 
         FIG. 7  is a view as seen in the direction of the arrow VII-VII in  FIG. 6 . 
         FIG. 8  is a view as seen in the direction of the arrow VIII-VIII in  FIG. 6 . 
         FIG. 9  is a front view of a hook assembly. 
         FIG. 10  is a front view of a hook assembly in a preferred embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Preferred Embodiment 
     Hereinafter, description will be made with respect to preferred embodiments of the present invention with an example of an outboard motor  1  in  FIG. 1 . However, the preferred embodiments described below are merely exemplary, and the present invention is not limited to the preferred embodiments described below. 
       FIG. 1  is a left side view of the outboard motor  1  according to a preferred embodiment. As shown in  FIG. 1 , the outboard motor  1  includes an outboard motor body  10  and a tilt mechanism  11 . The tilt mechanism  11  is arranged to perform tilt and trim operations of the outboard motor body  10 . 
     The tilt mechanism  11  preferably includes a mount bracket  12  and a swivel bracket  13 . The mount bracket  12  is fixed to a hull by a bolt or the like. The mount bracket  12  and the swivel bracket  13  are mutually mounted by a swing shaft  14 . The swivel bracket  13  is swingable about the axis of the swing shaft  14  with respect to the mount bracket  12 . The outboard motor body  10  is mounted on the swivel bracket  13 . 
     The outboard motor body  10  includes a housing  20 . A power source, a shift mechanism, and the like (not shown) are housed in the housing  20 . The power generated by the power source is transmitted to a propeller  15  shown in  FIG. 1 . The power source may be an engine or an electric motor, for example. 
     The housing  20  includes a top cowling  21  that is a second housing, a bottom cowling  22  that is a first housing, an upper casing  23 , and a lower casing  24 . The upper casing  23  is disposed on the lower casing  24 . The bottom cowling  22  is mounted on the upper casing  23 . The top cowling  21  is mounted on the bottom cowling  22 . The bottom cowling  22  and the top cowling  21  define a housing space for the power source (not shown). As shown in  FIG. 8 , a ring-shaped rubber elastic member  25 , for example, is disposed on the entire circumference between the bottom cowling  22  and the top cowling  21 . The elastic member  25  provides a seal between the bottom cowling  22  and the top cowling  21 . 
       FIG. 4  is a bottom view of the top cowling  21 . As shown in  FIG. 4 , the top cowling  21  includes a cowling body  21   a . A convex portion  21   b  is defined on the cowling body  21   a . The convex portion  21   b  is arranged on a front portion of the top cowling  21  and protrudes in a forward direction. On the other hand, a concave portion  22   a  is defined in the bottom cowling  22  shown in  FIG. 5 . The concave portion  22   a  is arranged on a front portion of the bottom cowling  22 . Engagement of the convex portion  21   b  and the concave portion  22   a  allows mutual attachment between the front portion of the top cowling  21  and the front portion of the bottom cowling  22 . 
     Moreover, as shown in  FIGS. 4 and 8 , an engaged member  26  is defined on the cowling body  21   a . The engaged member  26  is preferably arranged on the inside in a rear portion of the top cowling  21 . Meanwhile, as shown in  FIGS. 5 and 8 , a hook assembly  30  is defined on the bottom cowling  22 . Engagement of the hook assembly  30  with the engaged member  26  allows mutual attachment between the rear portion of the top cowling  21  and the rear portion of the bottom cowling  22 . 
     As shown in  FIG. 8 , the engaged member  26  preferably includes an engaging member body  27  and a bridge member  28 . The engaging member body  27  preferably includes a first plate member  27   a  and a second plate member  27   b . The first plate member  27   a  and the second plate member  27   b  are fixed to the cowling body  21   a  by a bolt  29 , for example. A distal portion of the first plate member  27   a  and a distal portion of the second plate member  27   b  are separated from each other. The substantially cylindrical bridge member  28  is bridged between the distal portion of the first plate member  27   a  and the distal portion of the second plate member  27   b.    
     As shown in  FIG. 9 , the hook assembly  30  preferably includes a rotation shaft  32 , a hook member  33 , a lever  31 , and a weight  37  that preferably functions as a rotation regulating member. 
     As shown in  FIG. 8 , the rotation shaft  32  is rotatably mounted to the bottom cowling  22 . The hook member  33  is fixed to an inner end of the rotation shaft  32 . As shown in  FIG. 9 , the hook member  33  includes a hook member body  33   a  and an engaging portion  33   b . The hook member body  33   a  is fixed to the rotation shaft  32 . The hook member body  33   a  is partially positioned on the opposite side from the lever  31  with respect to the rotation shaft  32 . 
     The engaging portion  33   b  is connected with the hook member body  33   a . A recessed portion  33   c  is provided in the engaging portion  33   b . The recessed portion  33   c  is opened toward one side R 1  of the rotation direction R. The recessed portion  33   c  engages or disengages the bridge member  28  of the engaged member  26  by a rotation of the engaging portion  33   b  about the rotation shaft  32 . 
     As shown in  FIG. 8 , the lever  31  is preferably fixed to an outer end of the rotation shaft  32 . The lever  31  is disposed on the outside of the bottom cowling  22 . As shown in  FIG. 9 , the lever  31  extends from the rotation shaft  32  to the other side R 2  which is opposite from the opening direction of the recessed portion  33   c.    
     As shown in  FIG. 6 , one end of a tension coil spring  35 , which is arranged as a biasing member, is mounted on the hook member  33 . The other end of the tension coil spring  35  is arranged on a fixing portion  22   d  provided on the bottom cowling  22 . The tension coil spring  35  urges the hook member  33  to the opposite direction from the opening direction of the recessed portion  33   c  in a state such that the hook member  33  and the engaged member  26  are engaged together. 
     As shown in  FIG. 9 , in the present preferred embodiment, the weight  37 , which is arranged as a rotation regulating member, is fixed on a portion of the hook member body  33   a  that is on the opposite side of the rotation shaft  32  from the lever  31 . That is, the weight  37  is positioned on the side of the opening direction R 1  of the recessed portion  33   c  with respect to the axis  32   c  of the rotation shaft  32 . The center of gravity of the weight  37  is positioned on the side of the rotation direction R 1  with respect to the axis  32   c  of the rotation shaft  32  in a state in which the hook member  33  and the engaged member  26  are engaged. Additionally, as shown in  FIGS. 7 and 9 , the weight  37  is fixed by a rivet  38 , for example. 
     The weight  37  is arranged to set the center of gravity of the hook assembly  30  in a position equal to the axis  32   c  of the rotation shaft  32  or on the side closer to the opening direction R 1  of the recessed portion  33   c  from the axis  32   c  of the rotation shaft  32  in a state where the hook member  33  and the engaged member  26  are engaged. More specifically, as shown in  FIG. 9 , in the present preferred embodiment, the center of gravity W 1  of the hook assembly  30  is positioned on the side closer to the opening direction R 1  of the recessed portion  33   c  from the axis  32   c  of the rotation shaft  32 . 
     Additionally, as shown in  FIG. 9 , in the present preferred embodiment, the center of gravity W 3  of the weight  37 , the axis  32   c  of the rotation shaft  32 , and the center of gravity W 4  of the lever  31  are aligned substantially linearly. 
     As shown in  FIG. 8 , an oil supply hole  22 f is provided in a mounting portion  22   e  of the bottom cowling  22  of the hook assembly  30 . The oil supply hole  22   f  opens up to the rotation shaft  32  and extends in an upward direction. Lubrication oil is preferably supplied from the oil supply hole  22   f  to a portion between the mounting portion  22   e  and the rotation shaft  32 . 
     Next, an engagement and disengagement procedure of the bottom cowling  22  with/from the top cowling  21  will be explained. When the top cowling  21  is mounted on the bottom cowling  22 , initially, the convex portion  21   b  is engaged with the concave portion  22   a . Then, the top cowling  21  and the bottom cowling  22  are butted together in a state such that the lever  31  is rotated to a position shown in  FIG. 3 . Thereafter, as shown in  FIG. 2 , the lever  31  is operated to be horizontal. This allows an engagement between the hook member  33  and the engaged member  26 , so that the top cowling  21  is fixed to the bottom cowling  22  as shown in  FIG. 8 . 
     When the top cowling  21  is separated from the bottom cowling  22 , the lever  31  is operated to move to a position shown in  FIG. 3 . This eliminates the engagement between the hook member  33  and the engaged member  26 . As a result, the top cowling  21  is removable from the bottom cowling  22 . 
     As described above, in the present preferred embodiment, the weight  37  as the rotation regulating member is provided as shown in  FIG. 9 . Accordingly, the center of gravity W 1  of the hook assembly  30  is positioned on the side closer to the opening direction R 1  of the recessed portion  33   c  with respect to axis  32   c  of the rotation shaft  32 . Consequently, the direction of the inertia force acting on the hook assembly  30  is the opening direction R 1  when an obstacle such as a standing timber, for example, collides with either of the upper casing  23  or the lower casing  24 . This collision applies a rearward force to either the upper casing  23  or the lower casing  24 , and thus rotation of the hook assembly  30  in the direction R 2  can be prevented even when the engaging portion  33   b  and the bridge member  28  are separated from each other. As a result, disengagement of the hook assembly  30  and the engaged member  26  can be prevented. This prevents separation of the top cowling  21  from the bottom cowling  22  when the obstacle such as a standing timber collides with the upper casing  23  or the lower casing  24 . 
     Additionally, in the present preferred embodiment, a description has been made of a case in which the center of gravity W 1  of the hook assembly  30  is preferably positioned on the side closer to the opening direction R 1  of the recessed portion  33   c  with respect to the axis  32   c  of the rotation shaft  32 . However, the center of gravity W 1  may be positioned adjacent to the axis  32   c  of the rotation shaft  32 . In a case where the center of gravity W 1  is positioned adjacent to the axis  32   c , the inertia force acting on the hook assembly  30  is not so large when the obstacle, such as a standing timber, collides with either the upper casing  23  or the lower casing  24 . Accordingly, in the similar manner, separation of the top cowling  21  from the bottom cowling  22  can be prevented. 
     Incidentally, for example, even when the center of gravity of the weight, the axis of the rotation shaft, and the center of gravity of the lever are not linearly aligned when seen from the extending direction of the axis of the rotation shaft  32 , the balance of the hook assembly is maintained as long as the lever is in a horizontal or substantially horizontal state. Therefore, rotation of the hook assembly can be prevented. However, in such a case, if the hook assembly is rotated even slightly, and thus the lever is no longer in a horizontal position, the balance of the hook assembly tends to become disproportionate, so that the hook assembly tends to easily rotate. 
     On the other hand, in the present preferred embodiment, the center of gravity W 3  of the weight  37 , the axis  32   c  of the rotation shaft  32 , and the center of gravity W 4  of the lever  31  are aligned substantially linearly as seen from the extending direction of the axis  32   c  of the rotation shaft  32  as shown in  FIG. 9 . This prevents a disproportionate condition in the balancing state of the hook assembly  30  even when the hook assembly  30  rotates and the lever  31  is not in a horizontal or substantially horizontal state. Accordingly, the rotation of the hook assembly  30  can be more effectively prevented by aligning the center of gravity W 3 , the axis  32   c , and the center of gravity W 4  substantially in a linear manner, as seen from the extending direction of the axis  32   c  as in the present preferred embodiment. 
     Incidentally, even when the center of gravity of the hook assembly is positioned on the side closer to the lever from the axis of the rotation shaft in a state in which the hook assembly engages with the engaged member, it is conceivable to prevent the cancellation of an engaged state between the hook assembly and the engaged member by providing a biasing member arranged to strongly urge the hook assembly in the direction R 1  shown in  FIG. 9 . However, in such a case, a great deal of power is required to operate the hook assembly. Accordingly, the operability of the hook assembly tends to be lowered. 
     On the other hand, in the present preferred embodiment, providing a biasing device that applies a strong biasing force is unnecessary. This achieves easy operability of the hook assembly  30 . 
     However, even when the center of gravity W 1  in a state in which the hook assembly  30  engages with the engaged member  26  is positioned on the side closer to the direction R 1  with respect to the axis  32   c , it is preferable to provide a tension coil spring  35  that applies a relatively small biasing force that has no influence on the operation of the hook assembly  30 . This effectively prevents the top cowling  21  from being separated from the bottom cowling  22 . 
     The fixing method of the weight  37  is not particularly limited. The weight  37  may be fixed to the hook member  33  by welding, for example. Alternatively, the weight  37  may be fixed to the hook member  33  by a screw, for example. However, it is more preferable that the weight  37  be fixed to the hook member  33  by the rivet  38  as in the present preferred embodiment. This is because the weight  37  can be strongly fixed and separation of the weight  37  from the hook member  33  can be more reliably prevented. 
     In the present preferred embodiment, the oil supply hole  22   f  is preferably arranged to extend upward. This allows the easy supply of the lubrication oil to a portion between the rotation shaft  32  and the mounting portion  22   e  in a state in which the lever  31  is horizontal. 
     Second Preferred Embodiment 
     In the first preferred embodiment, a description has been provided of an example in which the weight  37  preferably defines a rotation regulating member. However, the rotation regulating member is not limited to the weight  37 . That is, the rotation regulating member does not have to be a member that moves the center of gravity of the hook assembly to the side of the opening direction R 1 . 
     For example, the rotation regulating member may be a member that applies a reaction force in the rotation direction R 1  to the hook member when the hook assembly attempts to move in the rotation direction R 2 . In the present preferred embodiment, a description will be made of an example where the rotation regulating member is a member that applies the reaction force in the rotation direction R 1  to the hook member when the hook assembly attempts to move in the rotation direction R 2 . Additionally, in the description below, members that have substantially the same functions as those in the first preferred embodiment are denoted by the same reference numerals, and their descriptions are omitted. Moreover,  FIG. 8  is referred in common with the first preferred embodiment. 
     As shown in  FIG. 10 , in the present preferred embodiment, a first protrusion  33   d  and a second protrusion  33   e  arranged as rotation regulating members are defined in the engaging portion  33   b . The first protrusion  33   d  and the second protrusion  33   e  are preferably positioned on a side closer to the opening direction of the recessed portion  33   c  from the engaged member  26  in a state such that the hook member  33  and the engaged member  26  are engaged. The first protrusion  33   d  and the second protrusion  33   e  protrude in the radial direction from the hook member  33 . 
     Because of this, as shown in  FIG. 10 , when the hook assembly  30   a  moves to the side of the engaged member  26 , the first protrusion  33   d  engages with a horizontal portion  27   b   1  of the second plate member  27   b . Moreover, the second protrusion  33   e  engages with the bridge member  28 . Accordingly, when the hook assembly attempts to move in the rotation direction R 2 , in the first protrusion  33   d  and the second protrusion  33   e , the reaction force in the rotation direction R 1  acts on the engaging portion  33   b . This prevents rotation of the hook assembly  30   a  in the direction opposite from the opening direction of the recessed portion  33   c , so that a disengagement between the hook assembly  30   a  and the engaged portion  26  is prevented. As a result, separation of the top cowling  21  from the bottom cowling  22  can be prevented. 
     Additionally, only either the first protrusion  33   d  or the second protrusion  33   e  may be provided. Moreover, at least either the first protrusion  33   d  or the second protrusion  33   e  and the weight  37  in the first preferred embodiment may be provided. 
     While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

Technology Category: 4