Abstract:
A pivoting arrangement for connecting an actuator to the outboard drive portion of a marine propulsion unit and more particularly to an arrangement for strengthening the pivotal connection without significantly increasing its size and by simplifying its construction to reduce cost.

Description:
BACKGROUND OF INVENTION  
       [0001]     This invention relates to a pivoting arrangement for connecting an actuator to the outboard drive portion of a marine propulsion unit and more particularly to an arrangement for strengthening the pivotal connection without significantly increasing its size and by simplifying its construction to reduce cost.  
         [0002]     As is well known, many marine propulsion systems, particularly ones having larger displacements employ hydraulically operated trim and tilt controls. These systems generally permit trim adjustment when the watercraft is in motion and tilting up out of the water for trailering or service. In addition they generally incorporate a pop up damping arrangement that permits the propulsion unit to pop up when an underwater obstacle is encountered to prevent damage and return to the trim adjusted position when it is cleared.  
         [0003]     One such arrangement is shown in Published Japanese Application, publication number Hei 07-69289, published Mar. 14, 1995. As shown in that publication, the tilt and trim arrangement comprises a clamp bracket fixed to the watercrafthull and on which a propulsion unit is pivotally supported for the trim and tilt operation. This is accomplished by a tilt cylinder mounted with its axis extending in a generally vertical direction and capable of expanding and retracting in the axial direction. The lower end of the cylinder is pivotally supported by the clamp bracket through a lower pivot and its upper end is pivotally connected to the propulsion unit through an upper pivot. A pressurized oil control system for controlling oil delivery to accomplish the desired motion.  
         [0004]     As seen in that publication both the upper and lower pivotal connections require at least one pin receiving that receives a respective, separate pin that must be somehow connected to the propulsion unit and the clamping bracket that forms the attachment to the hull of the associated watercraft. This increases the number of parts and the assembly operation and obviously the cost. Also the use of separate pins can decrease or prevent the increase of the strength of the unit. Although strength can be increased by increasing the size, the construction does not offer excess space for such a resolution to the problem.  
         [0005]     In addition and particularly with the upper connection to the propulsion unit, a boss part is secured to the extended end portion of the piston rod and is of a generally hollow cylindrical shape to receive a pivot pin. Although the strength could be improved by increasing the diameter, surplus space in the outboard motor is limited and it is not easy to increase enough the outside diameter dimension of the boss part. Also since the pivot is provided by a pin in addition to the boss in the upper pivot member, the number of parts is increased and its construction and assembly is complicated.  
         [0006]     Therefore it is a principal object of the invention to provide a pivoting arrangement for connecting an actuator to the outboard drive portion of a marine propulsion unit and more particularly to an arrangement for strengthening the pivotal connection without significantly increasing its size and by simplifying its construction to reduce cost.  
       SUMMARY OF INVENTION  
       [0007]     A pivoting arrangement for effecting pivotal movement of a marine propulsion device adapted to be pivotally supported about a pivot axis on an associated watercraft. The pivoting arrangement comprises a cylinder assembly defining a cylinder bore and adapted to be pivotally connected to one of the watercraft and the marine propulsion device. A piston is supported for reciprocation within the cylinder bore and a piston rod is fixed to the piston for operation thereby. The piston rod extends externally of the cylinder assembly and adapted to be pivotally connected to the other of the watercraft and the marine propulsion device. In accordance with the invention, at least one of the pivotal connections are formed by a cylindrical portion formed by the associated component being pivotally connected. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0008]      FIG. 1  is a side elevational view of a portion of a watercraft (shown partially and in cross section) with a propulsion unit attached utilizing a tilt and trim unit constructed in accordance with the invention, showing the range of trim and tilt movements in phantom lines.  
         [0009]      FIG. 2  is a perspective view of the trim and tilt unit.  
         [0010]      FIG. 3  is an exploded perspective view of the clamping bracket.  
         [0011]      FIG. 4  is a partial cross sectional view of the tilt and trim unit taken through a transverse axis of the cylinder, showing the fully trimmed and tilted down position.  
         [0012]      FIG. 5  is a cross sectional, taken along the line  5 - 5  in  FIG. 4 , showing the pivotal connection between the piston rod and the outboard drive with the connecting parts being shown in phantom in an exploded portion of the figure.  
         [0013]      FIG. 6  is a cross sectional, in part similar to  FIG. 5 , showing another embodiment of the pivotal connection between the piston rod and the outboard drive with the connecting parts being shown in phantom in an exploded portion of this figure. 
     
    
     DETAILED DESCRIPTION  
       [0014]     Referring now in detail to the drawings and initially to  FIG. 1 , a watercraft propulsion unit in the form of an outboard motor  11  for propelling a watercraft such as a boat, indicated generally at  12 , is supported on a transom  13  formed at a rear of a hull  14  of the boat  12 . The outboard motor  11  includes, as part of its tilt and trim apparatus, a clamp bracket  15  removably mounted to the rear of the transom  13  of the hull  14  by means of fasteners (not shown).  
         [0015]     As is well known in the art, the outboard motor  11  includes a propulsion unit, indicated generally at  16  provided at a rear of the clamp bracket  15  and pivotally supported by an upper part of the clamp bracket  15  by means of a pivot pin  17  to allow a propulsion device such as a propeller  18  at the lower part of the propulsion unit  16  to pivot in a manner to be described. The propeller  18  is driven in any desired manner such as by an internal combustion engine.  
         [0016]     The upward pivotal movement from the fully tilted and trimmed down position shown in solid lines in  FIG. 1  is rearward and upward in the direction of the arrow A in this figure through a trim range B and a fully tilted up range C. This movement is effected and controlled by a hydraulic tilt and trim cylinder indicated generally by the reference numeral  21 . The tilt and trim cylinder is mounted with its axis  22 , to be described in more detail later by reference to the remaining figures, extending in a generally vertical direction with its lower end pivotally supported by a lower part of the clamp bracket  15  by means of a lower pivot  23 , as is well known in the art and in a specific manner to be described in more detail later.  
         [0017]     A piston rod (to be identified in more detail later) of the tilt and trim cylinder assembly  21  has its upper end pivotally connected to the propulsion unit  16  by means of an upper pivot  24 , in a manner as will also be described in more detail later. As will be described later, a pressurized oil control system controls delivery to/or exhaust from the chambers, to be described, of the tilt and trim cylinder  21  to operate the tilt and trim cylinder  21 .  
         [0018]     Referring now to  FIG. 2 , this shows in perspective, the tilt and trim cylinder  21  that includes a cylinder body, indicated generally by the reference numeral  25 , and from which the aforenoted piston rod  26  extends in a generally upward direction. Mounted to one side of the cylinder body  25  are some components of a hydraulic control system including a reversible electric motor (not shown) container in a housing  28  that contains a reversible electric motor, for a purpose to be described.  
         [0019]     As seen in this figure the upper pivot  24  comprises a cylindrical element  29  connected, in a manner to be described later primarily by reference to  FIGS. 4 and 5 , to a drive shaft housing  31  of the outboard motor  11  (see  FIG. 1 ). Also seen in this figure are a pair of integral projections  32  and  33  formed on opposite sides of the cylinder body  25  which function in a manner to be described by particular reference to  FIGS. 3 and 4  to provide the lower pivot  23 .  
         [0020]     Referring now to  FIG. 3  it will be seen that the clamp bracket  15  is comprised of cooperating left and right side members  34  and  35  that have respective bosses  36  and  37  that receive the pivot pin  17  for the pivotal support of the propulsion unit  16  for its tilt and trim movement. The lower portions of the side members  34  and  35  have bearing members  38  and  39  for pivotally receiving the projections  32  and  33  of the cylinder body  25  in a manner to be described.  
         [0021]     The hydraulic system for achieving the tilt and trim movement will now be described by reference to  FIG. 4 . As has already been noted, the tilt and trim cylinder  21  includes a cylinder body  25  that forms its outer shell and which is pivotally supported by the lower part of the clamp bracket  15  by means of the lower pivot  23 . The lower portion of the cylinder body  25  has a larger diameter cylinder bore  41  formed around the axis  22 , into which a large diameter piston  42  is fitted for reciprocation in the axial direction. The piston  42  divides the large cylinder bore  41  into an upper chamber  43  and a lower chamber  44 . The lower end of the large cylinder bore  41  and lower chamber  44  are closed by a closure plug  45  by means of a threaded connection  46  at the lower end of the large cylinder bore  41 .  
         [0022]     A smaller diameter cylinder bore  47  is formed around the axis  22  in a part of the cylinder body  25  above the large cylinder bore  41  with its lower end communicating with an upper end of the large cylinder bore  41 . A cylinder tube  48  is reciprocally fitted into the small cylinder bore  47  for movement in the axial direction and is fixed to the large piston  42 . A small piston assembly, indicated generally at  49 , is supported for reciprocation in a smaller cylinder bore  51  formed in the cylinder tube  48 . The small piston assembly  49  divides the smaller cylinder bore  51  into upper and lower bore portions  52  and  53 , respectively.  
         [0023]     The piston rod  26  is fixed to and extends upward from the small piston assembly  49  through an end wall if the cylinder housing  25  along the axis  22 . The upper, exposed end of the piston rod  26 , as has been noted, provides the pivotal connection to the propulsion unit  16  through the upper pivot  24 .  
         [0024]     A stopper ring  54  is fixed in the smaller cylinder bore  51  of the cylinder tube  48  to limit the downward movement of the small piston assembly  49  In a like manner, an upper stopper ring  55  is provided to prevent the small piston  49  from moving up further than an upper predetermined position in the smaller cylinder bore  51 .  
         [0025]     The small piston  49  is comprised of upper and lower piston portions  56  and  57  that are each individually reciprocal in the smaller cylinder bore  51 . The upper piston portion  56  divides the upper bore portion  49  of the smaller cylinder bore  51  into upper and lower areas. The piston rod  26  extends upward from the upper piston portion  54  through both the bore areas. The stopper ring  53  prevents the upper piston portion  54  of the small piston assembly  49  from moving up further than the predetermined position in the smaller cylinder bore  51 .  
         [0026]     The hydraulic system for controlling the trim and tilt operation is described in more detail my co-pending application entitled “TRIM SYSTEM FOR MARINE PROPULSION”, Ser. No. ______, filed concurrently with this application, Attorney Docket number SIMTEK6972, this hydraulic system operates to permit trim up from the fully trimmed down position shown here in  FIG. 4 , to a fully trimmed up position at a low speed but with a high force due to the large diameter of the piston  42  and then, if desired, to a fully tilted up position at a greater speed due to the smaller diameter of the piston assembly  49 . This difference in force and speed is desired because the trim operation is normally done when operating the associated watercraft in a forward direction but the tilt up operation is done when in a stationary position.  
         [0027]     As is also noted in the aforenoted co-pending application, the system operates to permit popping up from any set trim position is permitted when an underwater obstacle is encountered, how the popping up action is damped to a stop and the propulsion unit  16  can return to the trim adjusted position when the obstacle is cleared. This popping up and associated damping at the end of travel works from any trim adjusted position, as is also described in that co-pending application and for that reason further discussion thereof is not believed necessary for those skilled in the art to understand the invention hereof.  
         [0028]     In order to prevent direct metal to metal contact upon extreme pop up action and to cushion the stopping of such movement and as described in more detail in my related, co-pending application, entitled “TILT AND TRIM SYSTEM OF OUTBOARD DRIVE OF PROPULSION UNIT”, Ser. No. ______, filed concurrently herewith (Attorney Docket Number: SIMTEK6974), an oil lock piston  58  is fitted into the upper bore area of the upper bore portion  52  and normally disposed at a gap above the upper piston portion  54 . A small annular gap is formed between the inner peripheral surface of the upper bore portion  52  and the outer peripheral surface of the oil lock piston  58  for permitting oil to flow past the oil lock piston  58 .  
         [0029]     If the oil lock piston  58  is tending to move up further than the upper predetermined position in the upper end in the upper bore portion  52  of the smaller cylinder bore  51 , the oil lock piston  58  abuts directly with the stopper ring  55  and thus is prevented from moving up further. Since the oil lock piston  58  is thus prevented from moving up, the upper piston portion  56  is also prevented from moving up further.  
         [0030]     Since the hydraulic system for permitting and controlling these operations is not an important feature of the invention in this case and any desired system can be utilized the disclosure of the aforenoted co-pending applications is incorporated herein by reference and further description of it is not believed necessary to permit those skilled in the art to practice the invention hereof.  
         [0031]     The constructions of the pivotal connections  23  and  24  will now be described initially to the lower connection  23 , by principal reference to  FIGS. 2-4 . As has been noted, the lower pivot  23  comprises left and right projections  32  and  33  formed integrally with and projecting outward from the left and right sides of the cylinder body  25 . To provide an anti-frictional connection, complimentary plastic bushings  59  are fitted over these projections  32  and  33 . These are received in the aforenoted paired left and right bearing members  38  and  39  formed by the bracket members  34  and  35  of the clamp bracket  15  for pivoting the respective projections  32  and  33  about a lower axis, indicated at  61 .  
         [0032]     The bearing member  38  on one side has a boss  62  provided as projecting integrally with the bracket member  34  on one side facing the other bracket member  35 . The boss  62  is provided with a bearing bore  63  centered on the lower axis  61 . The projection  32  on one side is inserted together with its bushing  59  into the bearing bore  63  on the lower axis  61  and pivotally supported on the boss  62 .  
         [0033]     The bearing member  39  of the other side comprises a semicircular bearing member  64  for receiving the projection  33  on its underside through the lower portion of the bushing  59 . A semicircular holding member  65  for holding retaining the projection  33  in pivotal relation with the bearing member  64  and engaging the upper portion of the bushing  59 . Threaded fasteners  66  removably securing the holding member  65  to the bracket member  35  from the other side, so that the space between the bearing member  64  and the holding member  65  forms a bearing bore  67  into which the projection  33  is received and pivoted.  
         [0034]     Now the construction of the upper pivot member  24  will be described by reference to  FIGS. 4 and 5 . As has been noted, this comprises a solid cylindrical element  29  placed at the upper end of the axis  22  with its axially middle portion secured by a threaded connection  68  to an extended end portion of the piston rod  33 . The outer ends of the cylindrical element  29  cooperate with paired left and right cylindrical bearing bores  69  and  69  of a circular cross section formed in a manner to be described on the upper portion of the propulsion unit  16  on opposite sides of the cylinder axis  22 . The respective end portions of the element  29  are journalled in a manner to be described in respective of these bearing bores  69  to provide the pivotal connection to the propulsion unit  16 . Although a threaded connection is illustrated between the piston rod  26  and the cylindrical element  29  other means of attachment may be employed such as welding. Besides, both ends of the cylindrical element  29  may be of a truncated conical shape with its diameter dimension slightly tapering toward its ends.  
         [0035]     As best seen in  FIG. 5 , a semicircular arcuate recesses  71  that is forwardly open is formed in the upper portion of the propulsion unit  16 . Paired left and right securing members  72  are provided, facing the arcuate recess  71  from the front and secured respectively by means of threaded fasteners  73  to the upper portion of the propulsion unit  16 . Each of these securing members  72  is formed with a semicircular arcuate recess  74  facing the recess  71 . Thus bearing bores are formed between the upper portion of the propulsion unit  16  and the mutually opposite surfaces of the securing members by means of both the arcuate recesses  71  and  74 .  
         [0036]     In a “normal attitude” of the propulsion unit  16 , mutually matching surfaces  76  of the upper portion of the propulsion unit  16  and the securing members  72  are made approximately parallel to the axis  22  of the tilt cylinder  21 . Extensions of the planes of the matching surfaces  76  pass the vicinity of an upper axis, indicated at  77  of the cylindrical element  29  of the upper pivot  24 . To be more specific, in the above-described “normal attitude” of the propulsion unit  16 , while the matching surface  76  and the axis  22  of the tilt cylinder  21  in side view of the outboard motor  11  are approximately parallel to each other, the matching surface  76  extends approximately in a vertical direction and the axis  22  is slightly tilted to the matching surface  76  as indicated with a phantom line in  FIG. 5 .  
         [0037]     A pair of left and right support members  78  are formed integrally with the propulsion unit  16  projecting forward from the front face of the propulsion unit  16  support the respective securing members  72 . Therefore, the securing of the securing members  72  to the upper portion of the propulsion unit  16  is reinforced by the support members  78 . In other words, pivoting strength of the upper end portion of the tilt cylinder  21  onto the upper portion of the propulsion unit  16  is improved. In addition when the securing members  72  are secured by means of the threaded fasteners  73  to the upper portion of the propulsion unit  16 , it is possible to temporarily place the securing members  72  on the top surface of the support members  78 . Therefore, the work of securing the securing members  72  to the upper portion of the propulsion unit  16  is facilitated.  
         [0038]     For anti-friction operation, a plastic, hollow anti-friction cylindrical bushing, indicated generally at  79 , is fit over the cylindrical element  55  of the upper pivot  24 . Both ends of the cylindrical element  55  are pivoted through the bushing  79  on the inside cylindrical surfaces of the respective bearing bores  74 . The bushing  79  is split in the circumferential direction to form separated ends  81  that can be separated from each other by elastic deformation of the bushing  79 . Thus the bushing  79  can be fit to or removed from the cylindrical element  55  in its radial direction because of the separated ends  81 . In this case, cuts  82  are formed between both the separated ends  81  to clear the piston rod  33  when the ends  81  are released.  
         [0039]     The assembly and disassembly of the lower pivot  23  will now be described by reference to  FIG. 4 . As may be seen in this figure, when the threaded fasteners  66  are loosened and the semicircular holding member  65  can be removed from the bracket member  35 , the top side of the bearing member  39  is opened. Thus when the tilt cylinder  21  is wholly moved toward the bracket member  35  in the direction shown by the arrow B in  FIG. 4 , the opposite projection  32  can be removed from the boss  38  and the lower end of the cylinder  21  is freed. Then the cylinder  21  can be moved axially upwardly in the direction of the arrow C as shown in  FIG. 4 .  
         [0040]     Assembly is done in the opposite manner. That is, the removed tilt cylinder  21  is moved in the direction opposite to the above (opposite to the arrows C and B in that order) and the semicircular holding member  65  is attached by means of the threaded fasteners  66  to the bracket member  35  and both the projections  32  and  33  are pivoted again in the respective bearing members  38  and  39 .  
         [0041]     Since the holding member  65  is removable rather than integral, it may be desirable to provide a further reinforcing member  83 , as shown in phantom in  FIGS. 3 and 4 , integrally with the bracket member  35  for backing up the semicircular holding member  65 . Alternately the further reinforcing member  83  may be removably secured by means of other fasteners to the bracket member  35 .  
         [0042]      FIG. 6  shows another embodiment of the upper pivot member  14 . Since this embodiment is generally similar to the embodiment of  FIG. 5 , where components have the same or substantially the same construction they are identified by the same reference numbers and will be described again in detail only where necessary for those skilled in the art to understand and practice this embodiment. This embodiment differs from that previously described in the configuration of the mating faces of the propulsion unit  16  that define the upper pivot  24  and the securing member, here identified generally by the reference numeral  101 .  
         [0043]     As previously, the arcuate recess  71  of the propulsion unit  16  has a front opening however the upper and lower surfaces thereof, indicated at  102  extend forwardly parallel to each other in a generally horizontal direction. On the other hand, the securing member  101  has a mating projection  103  to be removably fit into the front edge opening of the arcuate recess  71 , and the projected edge face of the projection  103  is formed with the other arcuate recess  74 .  
         [0044]     Attachment with this embodiment is facilitated since the ends of the cylindrical element  29  can be positioned between the parallel edges  102  leading to the bearing bores  69  and the securing members  101  then are inserted therein and secured by the fasteners  73 . Therefore, in the attachment work, maintaining the fit state between the cylindrical element  29  of the upper pivot  24  and the arcuate recess  71  of the upper portion of the propulsion unit  16  is facilitated and accordingly the attachment work is facilitated.  
         [0045]     With the above described constructions, the lower pivot  23  comprises paired left and right projections  32  and  33  on the lower axis  61  projecting integrally from the outside surface of the cylinder body  25 , and cooperating paired left and right bearing members  38  and  39  for pivoting receiving the projections  32  and  33  about the lower axis  61 . Therefore, relative positions of the cylinder body  25  about the axis  22  of the tilt cylinder  21  and both the projections  32 ,  33  of the lower projection member  23  are maintained constant in contrast to the prior art constructions where the connection requires some adjustment to arrive at this relative position. Since such adjustment is unnecessary the attachment work is facilitated.  
         [0046]     In addition, since both the projections  32  and  33  to project integrally from the cylinder body  25 , the number of components of the outboard motor  11  is held reduced, so that its constitution become simple. Furthermore, both the projections  32  and  33  can be removed from both the bearing members  38  and  39  by moving the tilt cylinder  21  in the radial direction of the projections  32  and  33 . Because of this the coupling and releasing both the projections  32  and  33  onto the respective bearing members  38  and  39  can be accomplished without deforming the shape of the clamp bracket  15 . Therefore, the work of attaching the tilt cylinder  21  to the clamp bracket  15  can be done easily even though both the projections  32  and  33  are integral with the cylinder body  25 .  
         [0047]     Furthermore the upper pivot  24  is provided by a solid cylindrical element  55 , placed on the upper part of the cylinder axis  22 , with its axially middle portion secured to the extended end portion of the piston rod  33 , and with its both end portions inserted into and pivoted with the paired left and right bearing recesses  74  formed in the upper portion of the propulsion unit  16  on the upper part of the cylinder axis  22 . Therefore, it is possible to have a larger diameter it will have a sufficient strength.  
         [0048]     Because a component of hollow cylindrical shape is replaced with the cylindrical element  29  of solid cylindrical shape, the cylindrical element  29  is made to have sufficient strength even without increasing its outside diameter dimension. Also since this constitution uses the solid cylindrical element  29  in place of the conventional boss part and pivot, the number of components is reduced and accordingly the upper pivot member  24  becomes simple in construction.  
         [0049]     In addition the way the components are secured together, the work in pivotally connecting the upper end portion of the tilt cylinder  21  on the upper portion of the propulsion unit  16  is facilitated. In addition, since the extension plane of the mutually matching surfaces  76  of the upper portion of the propulsion unit  16  and the securing members  72  extend approximately parallel to the axis  22  of the tilt cylinder  21  and passes the vicinity of the upper axis  22  of the cylindrical element  55 , in the state that the propeller  18  of the lower end portion of the propulsion unit  16  is below the water surface and the axis  22  of the tilt cylinder  21  extends in a generally vertical direction, when an external force is applied to the propulsion unit  16  through the cylindrical element  55  of the upper pivot member  24  from the tilt cylinder  21  with an intention of swinging the propulsion unit  16 , the external force is divided and borne approximately evenly by the upper portion of the propulsion unit  16  and the securing members  72 .  
         [0050]     Of course those skilled in the art will readily understand that the described embodiments are only exemplary of forms that the invention may take and that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims.