Patent Publication Number: US-8992273-B2

Title: Cable steering system for a marine vessel which has a primary propulsion unit and an auxiliary propulsion unit

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part application of application Ser. No. 12/501,332 filed in the United States Patent and Trademark Office on Jul. 10, 2009 now U.S. Pat. No. 8,151,723, and priority to which is claimed. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a steering system for a marine vessel and, in particular, to a steering system for a marine vessel which has a primary propulsion unit and an auxiliary propulsion unit. 
     2. Description of the Related Art 
     Marine vessels are often provided with a primary propulsion unit and an auxiliary propulsion unit. Typically a tie bar couples the primary propulsion unit and the auxiliary propulsion unit. U.S. Pat. No. 6,406,340 to Fetchko et al. and U.S. Pat. No. 7,128,626 to Dudra et al., the full disclosures of which are incorporated herein by reference, both disclose using a tie bar to couple a primary propulsion unit and an auxiliary propulsion unit. This allows the propulsion units to be steered simultaneously. 
     It is also known to use a cable to couple a primary propulsion unit and an auxiliary propulsion unit. U.S. Pat. No. 4,836,812 to Griffiths, the full disclosure of which is also incorporated herein by reference, discloses using a cable to couple a hydraulic cylinder of a primary propulsion unit to a steering arm of an auxiliary propulsion unit. Coupling the propulsion units with a cable provides the advantage of a flexible and rotatable connecting member. However, connecting the cable to the hydraulic cylinder of the primary propulsion engine may limit rotation of the cable and/or unduly twist the cable when primary propulsion unit is tilted. This may result in jamming and less motion being transmitted to the auxiliary propulsion unit. 
     There is accordingly a need for an improved steering system for a marine vessel which has a primary propulsion unit and an auxiliary propulsion unit. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide an improved steering system for a marine vessel which has a first propulsion unit and a second propulsion unit. 
     In particular, it is an object of the present invention to provide an improved steering system for a marine vessel in which a cable couples a primary propulsion unit to an auxiliary propulsion unit. 
     There is accordingly provided a steering system which comprises a steering assembly for steering a first propulsion unit. The steering assembly includes an actuator for imparting steering movement to the first propulsion unit. A push/pull cable operatively connects the actuator to a second propulsion unit. The push/pull cable extends through a tilt tube of the first propulsion unit and is capable of transmitting steering movement from the actuator to the auxiliary propulsion unit. The first propulsion unit may be a primary propulsion unit and the second propulsion unit may be an auxiliary propulsion unit. The push/pull cable may extend through a tilt tube of the second propulsion unit. 
     There is further provided a steering system which comprises a transom bracket provided with a support rod having a passageway extending therethrough. A steering assembly for steering the first propulsion unit is mounted on the transom bracket. The steering assembly includes an actuator for imparting steering movement to the first propulsion unit. A push/pull cable extends between the first propulsion unit and a second propulsion unit for operatively connecting the actuator of the first propulsion unit to the second propulsion unit. The push/pull cable extends through the support rod and the push/pull cable is capable of transmitting steering movement from the actuator of the first propulsion unit to the second propulsion unit. The first propulsion unit may be a primary propulsion unit in the form of a stern drive and the second propulsion unit may be an auxiliary propulsion unit in the form of an outboard motor. 
     The steering system may be mounted on the transom bracket. The push/pull cable may extend through a tilt tube of the second propulsion unit. A connecting arm may operatively connect the push/pull cable to the actuator of the first propulsion unit. A steering arm may operatively connect the push/pull cable to a steering member of the second propulsion unit. The actuator of the first propulsion unit may include a hydraulic cylinder having a piston rod reciprocatingly mounted therein. The support rod and the piston rod may be substantially parallel. At least a portion of the push/pull cable is coaxial with the support rod. At least a portion of the push/pull cable is coaxial with the tilt tube of the second propulsion unit. 
     There is still further provided a method for coupling a first propulsion unit to a second propulsion unit. One embodiment of the method comprises: 
     providing a support rod of the first propulsion unit with an axial passageway which extends therethrough; 
     providing a tilt tube of the second propulsion unit with an axial passageway which extends therethrough; 
     connecting a push/pull cable to a steering assembly of the first propulsion unit; 
     extending the push/pull cable through the passageway in the support rod and the passageway in the tilt tube of the second propulsion unit; and 
     steeringly connecting the push/pull cable to the second propulsion unit so that the push/pull cable is capable of transmitting steering movement from the actuator of the first propulsion unit to the second propulsion unit. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention will be more readily understood from the following description of following embodiments thereof given, by way of example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a front perspective view of a first embodiment of an improved steering system for a marine vessel which has a primary propulsion unit and an auxiliary propulsion unit; 
         FIG. 2  is a partially broken, back perspective view of the primary propulsion unit of  FIG. 1 ; 
         FIG. 3  is a sectional view showing a push/pull cable extending through a support rod which in turn extends through a tilt tube of the primary propulsion unit of  FIG. 1 ; 
         FIG. 4  is a fragmentary, sectional view showing ends of the tilt tube of  FIG. 3  in greater detail; 
         FIG. 5  is a fragmentary, sectional view showing an end of the support rod of  FIG. 3  in greater detail; 
         FIG. 6  is a front elevation view of a second embodiment of an improved steering system for a marine vessel which has a primary propulsion unit and an auxiliary propulsion unit; 
         FIG. 7  is a side, rear perspective view of the steering system of  FIG. 6  showing the primary propulsion unit and the auxiliary propulsion unit; 
         FIG. 8  is a side, front perspective view of the steering system of  FIG. 6 . 
     
    
    
     DESCRIPTIONS OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings and first to  FIG. 1 , this shows a first embodiment of a steering system  10  for a marine vessel  12  which is shown in fragment. The marine vessel  12  is provided with a first propulsion unit in the form of a primary propulsion unit  14  and a second propulsion unit in the form of an auxiliary propulsion unit  16 . The propulsion units  14  and  16  are both mounted on a stern  18  of the marine vessel  12 . The steering system  10  couples the propulsion units  14  and  16 . In this example, the primary propulsion unit  14  and auxiliary propulsion unit  16  are both outboard engines. The primary propulsion unit  14  allows an operator to operate the marine vessel  12  at high speeds for recreational activities such as travelling to fishing destinations. The auxiliary propulsion unit  16  allows the operator to operate the marine vessel  12  at low speeds for recreational activities such as trolling. In other embodiments, a pair of inboard/outboard engines may be twinned or an outboard engine may be coupled to a stern drive. 
     The steering system  10  includes a hydraulic steering assembly  20  which steers the primary propulsion unit  14 . The steering assembly  20  includes an actuator in the form of hydraulic cylinder  22  with a piston rod  24  reciprocatingly mounted therein allowing for relative movement of the cylinder  22  along a piston rod axis  100 . The cylinder  22  has a pair of spaced-apart cylinder arms  26  and  28  which extend radially outward of the cylinder  22 . A pivot plate  30  is pivotably connected to each of the cylinder arms  26  and  28  by means of pivot pins  27  and  29 , respectively. The pivot plate  30  extends between the cylinder arms  26  and  28  and can pivot about the pins  27  and  29 . A steering member or tiller  32  of the primary propulsion unit  14  is pivotably connected to the pivot plate  30  by a pivot pin  31 . Support arms  34  and  36  connect respective ends of the piston rod  24  to a support rod  38  of a tilt tube  40  of the primary propulsion unit  14 . This is better shown in  FIG. 2 . The support arms  34  and  36  restrict axial movement of the piston rod  24  relative to the marine vessel  12 . The support arms  34  and  36  also allow arcuate movement of the cylinder  22  and piston rod  24 , about a tilt axis  105 , while maintaining the piston rod axis parallel to the tilt axis  105 . 
     Referring back to  FIG. 1 , hydraulic conduits  42  and  44  hydraulically connect opposite ends of the cylinder  22  to a helm pump (not shown). Hydraulic fluid pumped from the helm pump actuates the cylinder  22  to reciprocate linearly relative to the piston rod  24  as is well known in the art. The piston rod  24  remains axially stationary relative to the marine vessel  12  while the cylinder  22  reciprocates linearly relative to the marine vessel  12 . This relative linear movement of the cylinder  22  causes the tiller  32  of the primary propulsion unit  14  to pivot, thereby causing the primary propulsion unit  14  to be steered. As thus far described the steering assembly  20  is conventional and accordingly will not be described in further detail herein. 
     The relative linear movement of the cylinder  22  is also transmitted by a connecting member, in the form of a push/pull cable  46 , to the auxiliary propulsion unit  16 , thereby causing the auxiliary propulsion unit  16  to be steered. The push/pull cable  46  is a conventional push/pull cable. The push/pull cable  46  is provided with cable rods  48  and  50  at opposite ends thereof. As shown in  FIG. 1 , a first one of the cable rods  48  threadedly engages a rod end  52  provided with an aperture or socket  54  which receives an L-shaped connecting arm  56 . The connecting arm  56  is pivotably connected to a bracket  58  by a pivot pin  60 . This allows the connecting arm  56  to pivot about an axis which is generally perpendicular to the piston rod axis  100 . The bracket  58  is pivotably connected to the pivot plate  30  of the steering assembly  20  by a pivot pin  62  as shown in  FIG. 1 . This allows the bracket  58  to pivot about an axis which is generally parallel to the piston rod axis  100 . A second one of the cable rods  50  threadedly engages a rod end  64  provided with an aperture or socket  66  which receives an L-shaped steering arm  68 . The steering arm  68  is pivotably connected to a steering member or tiller  70  of the auxiliary propulsion unit  16  by a pivot pin  72 . This allows the steering arm  68  to pivot about an axis which is generally perpendicular to the piston rod axis  100 . The push/pull cable  46  thereby steeringly couples the propulsion units  14  and  16 . 
     The push/pull cable  46  extends from the connecting arm  56 , through both the tilt tube  40  of the primary propulsion unit  14  and a tilt tube  74  of the auxiliary propulsion unit  16 , to the steering arm  68 . In one embodiment the tilt tubes  40  and  74  are substantially aligned along a common horizontal axis. The push/pull cable  46  accordingly extends substantially linearly in the horizontal direction. However, the cable is also flexible, allowing it to curve if required, for example, if the tilt tubes  40  and  74  are not aligned. The bend shown in  FIG. 1  is exaggerated for purposes of illustration. 
     Referring now to  FIG. 3 , this shows a cross-sectional view of the tilt tube  40  of the primary propulsion unit  14 . The tilt tube  40  is hollow and the support rod  38  extends through the tilt tube  40 . The support rod  38  is also hollow, or bored out, and the push/pull cable  46  extends through a central, axially passageway or a bore  47  of the support rod  38 . As better shown in  FIGS. 4 and 5 , the support rod  38  extends axially beyond the tilt tube  40  and is provided with threads  76  and  78  at each end thereof. This allows the support rod  38  receive the support arms  34  and  36  as described above. End caps  80  and  82  threadedly engage the support rod  38  to secure the support arms  34  and  36  in position. 
     The push/pull cable  46  also has a cable portion  84 . The cable portion  84  extends between the cable rods  48  and  50 . As seen in  FIGS. 4 and 5  for the first cable rod  48 , each cable rod has a bore  85  at the end adjacent to the cable portion  84 . The cable portion  84  is received within the bore  85  and is crimped in place in this example. 
     The push/pull cable  46  further includes an outer sleeve or jacket  86  which extends between the propulsion units  14  and  16  and, at least partially, houses the cable portion  84 . As shown in  FIGS. 4 and 5 , in this example, the jacket  86  is connected to an end cap  82  of the support rod of the primary propulsion unit. Similarly, and as shown in  FIG. 1 , the jacket  86  is also connected to an end cap  88  of the auxiliary propulsion unit  16 . The cable portion  84  is able to reciprocate within the jacket  86  and transmits linear movement from the first cable rod  48  to the second cable rod  50 . 
     In operation, an operator steers the primary propulsion unit  14  by actuating the helm pump to pump hydraulic fluid to the cylinder  22  of the steering system  20 . This causes the cylinder  22  to reciprocate linearly with respect to the marine vessel  12  as described above. This relative linear movement of the cylinder  22  causes the tiller  32  of the primary propulsion unit  14  to pivot, thereby causing the primary propulsion unit  14  to be steered. The relative linear movement of the cylinder  22  is also transmitted to the auxiliary propulsion unit  16 , thereby causing the auxiliary propulsion unit  16  to be steered. In particular, the relative linear movement of the cylinder  22  is transmitted through the bracket  58  and connecting arm  56  to the first cable rod  48  of the push/pull cable  46 . This causes the first cable rod  48  to move linearly. The linear movement of the first cable rod  48  is transmitted through the cable portion  84  of the push/pull cable  46  to the second cable rod  50 . This cause the second cable rod  50  to move linearly. Movement of the second cable rod  50 , through the steering arm  68 , causes the tiller  70  of the auxiliary propulsion unit  14  to pivot thereby causing the auxiliary propulsion unit to be steered. 
     Extending the push/pull cable  46  through tilt tubes  40  and  74  and, in particular through the support rods of the tilt tubes, allows for independent tilting of the primary propulsion unit  14  and the auxiliary propulsion unit  16 . Furthermore, twisting of the push/pull cable  46  is minimized. 
     Referring now to  FIGS. 6 to 8 , these show a second embodiment of a steering system  110  for a marine vessel  112  which is shown in fragment. The marine vessel  112  is provided with a first propulsion unit in the form of a primary propulsion unit  114  and a second propulsion unit in the form of an auxiliary propulsion unit  116 . The propulsion units  114  and  116  are both mounted on a stern  118  of the marine vessel  112 . In this example, the primary propulsion unit  114  is a stern drive and the auxiliary propulsion unit  116  is an outboard motor. The steering system  110  also includes a hydraulic steering assembly  120 , best shown in  FIG. 8 , which steers the primary propulsion unit  114 . The hydraulic steering assembly  120  is substantially similar to the hydraulic steering assembly  20  shown in  FIG. 1  and is accordingly not described in detail herein except with respect to the differences therebetween. It will be understood however by a person skilled in the art that in the hydraulic steering system  20  shown in  FIG. 1  the pivot plate  30  is positioned above the hydraulic cylinder  22 , while in the hydraulic steering assembly  120 , best shown in  FIG. 8 , a pivot plate  130  is positioned below the hydraulic cylinder  122 . 
     The hydraulic steering assembly  120  is mounted on mounting bracket which is a transom bracket  121  in this example. The transom bracket  121  is provided with a support rod  138  as best shown in  FIG. 8 . There is a central, axial passageway extending through the support rod  138  similar to central, axial passageway  47  of the support rod  38  shown in  FIGS. 3 and 4 . The support rod  138  extends substantially parallel to a piston rod  124  of the steering assembly  120 . A push/pull cable  146  extends from the primary propulsion unit  114 , through the support rod  124 , to the auxiliary propulsion unit  116 . The push/pull  146  cable is substantially similar to the push/pull cable  46  of  FIGS. 1 to 5  and is provided with cable rods  148  and  150  at opposite ends thereof. A first one of the cable rods  148  is coupled to the hydraulic steering assembly  120  of the primary propulsion unit  114  and a second one of the cable rods  150  is coupled to a steering member or tiller  170  of the auxiliary propulsion unit  116 . In particular, the cable rods  148  and  150  are respectively connected to the primary propulsion unit  114  and auxiliary propulsion unit  116  in a manner substantially similar as described above for the steering system shown in  FIG. 1 . The first one of the cable rods  148  is connected to an L-shaped connecting arm  156  of the hydraulic steering assembly  120  and the second one of the cable rods  150  is connected to an L-shaped steering arm  168  which is pivotably connected to the tiller  170  of the auxiliary propulsion unit  116 . The push/pull cable  146  also extends through a tilt tube  174  of the auxiliary propulsion unit  116 . 
     Accordingly, the steering system disclosed herein may be retrofitted to existing marine vessels by boring through the tilt tubes of existing propulsion units or by providing support rods for the tilt tubes with central passageways or bores to receive a push/pull cable. For example, the steering system disclosed herein may be retrofitted to the SEA STAR® steering system. 
     It will further be understood by a person skilled in the art that many of the details provided above are by way of example only, and are not intended to limit the scope of the invention which is to be determined with reference to the following claims.