Marine propulsion unit and apparatus for collecting line thereon

A line collector for a marine propulsion unit comprises a spool-like body for collecting fishing line, nets, weeds, and other debris. The line collector can be positioned between two propellers to protect an internal seal of the marine propulsion unit.

BACKGROUND OF THE INVENTION

In marine propulsion units having a gear case below the water line and at least one propeller mounted on a propeller shaft, at least one first seal is normally applied on the propeller shaft for preventing water from entering the drive housing and at least one second seal is normally applied on the propeller shaft for preventing transmission lubricants or oil from leaking out into the water.

Fishing lines, nets, weeds, and other debris can catch on the propeller, and can wind around the propeller shaft as it rotates. The fishing line, etc. can work into the housing of the propulsion unit and can damage the seals, thereby resulting in leakage of water into the housing and/or leakage of lubricants or oil out of the housing.

A common solution proposed for the entanglement issue in single propeller marine propulsion units is the provision of a line cutter, which is typically placed near the strut and operates by cutting fishing lines and debris away from the propeller shaft. However, such line cutters are high maintenance because placement near the strut makes installation and servicing difficult, in addition to exposing a potentially dangerous sharp cutting edge. Furthermore, line cutters do not exist for single or dual propeller systems with a gear case below the water line, which form a significant proportion of all marine propulsion units.

BRIEF DESCRIPTION OF THE INVENTION

A marine propulsion unit according to one aspect of the invention comprises a first propeller coupled with a first propeller shaft, a second propeller coupled with a second propeller shaft, wherein the first and second propeller shafts are concentric, at least one seal between the first and second propeller shafts, and a line collector positioned between the first and second propellers for collecting line caught by the propellers, and directing the line away from the at least one seal.

In accordance with another aspect of the invention, an apparatus for collecting line caught by a propeller on a marine propulsion unit comprises a first section having a first central bore configured to receive a propeller shaft coupled with the propeller, and a second section joined to the first section and having a second central bore configured to receive the propeller shaft, wherein the first section has an outer annular surface with a first outer diameter and the second section has an outer annular surface with a second outer diameter that is less than the first outer diameter at the junction of the first and second sections, and whereby line caught by the propeller can be collected on the second section substantially at the second outer diameter.

DETAILED DESCRIPTION

The present invention relates generally to protecting the seal(s) of a propulsion unit of a marine drive. For purposes of description related to the figures, it is to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.

FIG. 1is a side view of a marine drive10according to a first embodiment of the invention. The marine drive10can be provided on a boat100and comprises an engine12operably connected with a propulsion unit14. The propulsion unit14is illustrated as having a dual propeller system16which includes two counter-rotating propellers, a fore propeller16aand an aft propeller16b. One example of a suitable marine drive10is the Volvo Penta Inboard Performance System (IPS), in which the propellers16a,16bare forward-facing, thereby facing in direction of travel of the boat100. The marine drive10can be used singly on the boat100or in combination with one or more additional marine drives10provided the boat100, such as in a twin mounting arrangement in which two marine drives10are mounted next to one another. The marine drive10can have a gear case or housing18below the water line of the boat100, which may be defined by a bottom102of the boat100, although it is understood that the actual water line may be above the bottom102of the boat100when in use. Therefore, the housing18may be above the bottom102of some boats100, but still be below the water line.

FIG. 2is a cross-sectional view though line2-2ofFIG. 1. The propulsion unit14further comprises the gear case or housing18and a pair of concentric propeller shafts which extend from the housing18, an inner propeller shaft20which drives the fore propeller16aand a hollow outer propeller shaft22through which the inner propeller shaft20extends and which drives the aft propeller16b. The engine12(FIG. 1) drives the rotation of the shafts20,22in opposite directions via a conventional transmission (not shown) at least partially contained within the housing18. A spinner cone24can be mounted forwardly or upstream of the fore propeller16a.

A first water seal26is provided between the inner propeller shaft20and the outer propeller shaft22, and faces forwardly for preventing water from entering the propulsion unit14. A second oil seal28is provided on the inner propeller shaft20and the outer propeller shaft22, and faces rearwardly for preventing transmission lubricants or oil from leaking out into the water from the housing18.

A line collector30is mounted between the propellers16a,16bfor collecting debris which may be caught by the propellers16a,16band for directing it away from one or both of the seals26,28, as explained in detail below. As used herein, the term “line” or variations thereof refers to debris in a marine environment that may be caught by the propellers16a,16, including but not limited to fishing line, nets, strands, weeds, and the like.

FIG. 3is a partially exploded view of a portion of the propulsion unit14of the marine drive10ofFIG. 1. The propellers16a,16beach comprise a hub32with a plurality of blades34extending therefrom. Each hub32includes a central cavity36. As illustrated, the fore propeller16acomprises three blades34and the aft propeller16bcomprises four blades34, although other blade configurations are possible.

The propeller shafts20,22can be provided with a structure for retaining the dual propeller system16thereon in a fixed angular relationship such that the propellers16a,16bcannot rotate relative to the shaft20,22during normal operation of the propulsion unit14. As shown, the retaining structure can include a set of external splines38formed on the shafts20,22which are received by a cooperating set of internal splines40formed in the hubs32of the propellers16a,16b.

The inner propeller shaft20can further be provided with a structure for retaining the spinner cone24thereon in a fixed angular relationship such that the spinner cone24cannot rotate relative to the shaft20during normal operation of the propulsion unit14. As shown, the retaining structure can include set of external threads42formed on the shaft20, forwardly of the splines38, which are received by a cooperating set of threads (not shown) formed in the spinner cone24.

FIG. 4is a plan view of the line collector30ofFIG. 1. The line collector has a collecting section on which line is collected, and a directing section which directs line toward the collecting section. The line collector30illustrated herein has a spool-like or spool-shaped body44having a first end face46, a second end face48, and a central bore50extending through the body44from the first end face46to the second end face48. The body44includes a first flange52defining the first end face46and a second flange54spaced from the first flange52and defining the second end face48. The second flange54can have a reduced outer diameter D1 in comparison to the outer diameter D0 of the first flange52. A barrel56between the flanges52,54is formed by a further reduced outer diameter portion D2 of the body44. The body44can be formed as a single component as by machining, milling, casting, molding, or the like; alternatively, one or more of the flanges52,54and the barrel56can be manufactured separately, and assembled together, such as by welding the pieces together, for example.

The first flange52has a first inner face58opposite the first end face46and connected thereto by an outer annular surface or rim60. The inner and end faces58,46can be substantially parallel to each other as shown herein. The first flange52has one or more openings62extending through the inner and end faces58,46for assembling the line collector30with the aft propeller16b, as described below. As shown herein, four equally-spaced openings62can be provided.

The second flange54has a second inner face66opposite the second end face48and connected thereto by an outer annular surface or rim68. The inner and end faces66,48can be oriented at an angle to one another, which facilitates line collection, as described below. As shown herein, the inner face66can be canted in an outward direction from the outer annular surface of the barrel56in an aft direction, at an angle θ from vertical, such that the diameter of the inner face66tapers toward the barrel56. One or more cut-outs70on the second flange54provide a pass through for tools used during installation of the line collector30on the aft propeller16b, as described below.

The dimensions for the line collector30can vary depending on the application of the line collector30, and the dimensions of the propulsion unit14on which the line collector30is installed. One non-limiting example of a set of dimensions for the line collector30are: an outer diameter of the first flange52, D0=3.726 inches (9.464 cm); an outer diameter of the second flange54, D1=3.460 inches (8.788 cm); and outer diameter of the barrel56, D2=2.615 inches (6.642 cm); an inner diameter of the central bore, D3=2.415 inches (6.134 cm); a distance between centers of opposing openings62, D4=3.156 inches (8.016 cm); a diameter of openings62, D5=0.326 inches (0.828 cm); a length of body44, L0=2.592 inches (6.584 cm), a length of outer rim60, L1=0.592 inches (1.504 cm); a length of outer rim68, L2=0.125 inches (0.318 cm); a width of cut-outs70, W=0.5625 inches (1.429 cm); and an angle of the inner face66from vertical, θ=30.°

Suitable materials for the line collector30can also vary depending on the application of the line collector30, such as upon the marine environment in which the line collector30will be used. Some examples of materials that may be suitable for the line collector30are stainless steel, bronze, nickel-aluminum-bronze alloys, other materials that are corrosion resistant.

Referring back toFIGS. 2 and 3, the aft propeller16bcan further be provided with a structure for retaining the line collector30in a fixed angular relationship with the aft propeller16b, such that the line collector30cannot rotate relative to the aft propeller16bduring normal operation of the propulsion unit14, while permitting the line collector30to rotate relative to the counter-rotating fore propeller16a. As shown, the retaining structure can include the set of openings62in the first flange52and a corresponding set of openings72in the hub32of the aft propeller16b, which can receive fasteners74to couple the line collector30to the aft propeller16b. The fasteners74and the openings72can be threaded to maintain a tight connection. The cut-outs70are aligned with the openings62, such that a tool can be used during installation of the line collector30on the aft propeller16bto install and/or tighten the fasteners72.

While the primary function of the cut-outs70is to facilitate installation of the line collector30, in some, but not all, instances, the cut-outs70can provide a secondary function of cutting or severing fishing line, nets, weeds, and other debris encountered by the line collector30. However, the overall purpose of the line collector30is to direct fishing line, nets, weeds, and other debris away from the internal seal(s), and not to cut debris. Alternatively, a line cutter as known in the art can be provided on the line collector30to enhance the cutting capabilities of the line collector30.

The line collector30is at least partially exterior to the propellers16a,16b, such that at least a portion of the line collector30is exposed to the marine environment during operation. As illustrated, the barrel56of the line collector30can be exposed to the marine environment during operation, with a portion of the line collector30received within the central cavities36of the hubs32. Specifically, at least a portion of the central cavity36of the aft propeller16bcan be sized to receive the first flange52. Likewise, at least a portion of the central cavity36of the fore propeller16acan be sized to receive the second flange54. Since the fore propeller16arotates relative to the line collector30, a clearance can be provided between the second flange54and the hub32of the fore propeller16a.

As noted above, the line collector30functions to direct line away from one or both of the seals26,28and collect the line so that the line cannot damage the seals26,28. The second flange54with the tapered or angled inner face66defines the directing section of the line collector30since the inner face66directs line toward the barrel56, and the barrel56defines the collection section of the line collector30, since line is collected on the barrel56.

In operation, the line collector30can function to prevent failure of one or more of the seal(s)26,28shown inFIG. 2. Without the line collector30, fishing line, nets, weeds, and other debris can work under the aft propeller16b, and can cause failure of the water seal26, and in some cases the oil seal28. If the water seal26fails, water can enter the propulsion unit14, potentially causing failure of the marine drive10. If the oil seal28fails, transmission lubricants or oil can leak out from the housing18. The line collector30prevents fishing line, nets, weeds, and other debris from getting to the seals26,28and collects such debris on the barrel56before it can do damage. Features of the line collector30such as its spool-shaped body44and the angled inner face66help to direct debris toward the barrel56. While line and debris collection and guidance away from the seals26,28are the primary benefit provided by the line collector30, one side effect of the rotation of the line collector30caused by its coupling to the aft propeller16bis possible cutting or severing of lines and debris, which can also help protect the seals26,28. However, while the line collection feature is dependable with the line collector30, line cutting is irregular and not as dependable.

While the line collector30is shown and described with respect to a marine propulsion unit14having a forward-facing dual propeller system16inFIGS. 1-3, it is understood that that the line collector30can be used with other types of marine propulsion units, including a rearward-facing dual propeller system and a single propeller system. Furthermore, while the marine drive10is illustrated as comprising an inboard drive, the line collector30can also be used in conjunction with outdrives, stern drives, and pod drives. Two examples of alternate marine propulsion units are shown inFIGS. 6-7.

FIG. 6is a side view of a marine propulsion unit114comprising a line collector30according to a second embodiment of the invention, the marine propulsion unit114being mounted to the transom of boat100. The marine propulsion unit114can have a similar structure as described above for the first embodiment, with one exception being that it comprises a rearward-facing dual propeller system116having fore and aft propellers116a,116bextending from a gear case or housing118. The housing118can be located below the water line of the boat100.

The line collector30can be positioned between the propellers116a,116, in much the same manner as disclosed above for the first embodiment. In this embodiment, the first flange52(FIG. 4) of the line collector30can be attached to the fore propeller116a. The internal seals, while not shown, can be provided between shafts for the propellers116a,116bas described above. The line collector30can function to protect the internal seals from damage caused by fishing line, nets, weeds, and other debris.

FIG. 7is a side view of a marine propulsion unit214comprising a line collector30according to a third embodiment of the invention, the marine propulsion unit214being mounted to the transom of a boat100. The marine propulsion unit214comprises a single propeller system having a single propeller216extending from a gear case or housing218. The housing218can be located below the water line of the boat100.

The line collector30can be positioned between the propeller216and the housing218in much the same manner as disclosed above for the first embodiment. In this embodiment, the first flange52(FIG. 4) of the line collector30can be attached to the housing218. In this case, the line collector30can function to protect a strut bearing within the housing218from damage caused by fishing line, nets, weeds, and other debris.

FIG. 8is a partially exploded view of a portion of a propulsion unit14according to a fourth embodiment of the invention. The propulsion unit14is substantially similar to the propulsion unit14shown inFIG. 3, and can be used with the marine drive10shown inFIG. 1, with the exception of the line collector30. In the fourth embodiment, the line collector30is substantially identical to the line collector30shown inFIGS. 4-5, except that the spool-shaped body44of the line collector30can be formed in multiple sections, rather than the one piece body44shown inFIGS. 4-5. In particular, the second flange54can be a separate section from the first flange52and the barrel56. The second flange54attached to the barrel56using a welding technique, or using at least one mechanical fastener. As shown herein, the second flange54has one or more openings76extending there through for assembling the second flange54with the barrel56. As shown herein, four equally-spaced openings76can be provided between the cut-outs70. A corresponding set of openings78can be provided in the barrel56, which can receive fasteners80to couple the second flange54to the barrel56. The fasteners80and the openings78can be threaded to maintain a tight connection. Alternatively, the openings76,78in the second flange54and barrel56can be aligned with the openings62,72in the first flange52and the hub32such that only the first fasteners74are need to couple the line collector30together and to the hub32.

While the line collector30is shown inFIG. 8as being formed in two separate sections, it is also contemplated that the line collector30can be formed in three sections, with the first flange52, second flange54, and barrel56all comprising separate sections that are joined together as described above. In still another variation, the first flange52can be formed as a separate section from the second flange54and the barrel56.

The line collector30disclosed herein provides several advantages to propulsion units and marine drives. One advantage that may be realized in the practice of some embodiments of the described device is that the line collector30may greatly reduce or stop seal failure caused by the entanglement of fishing line, nets, weeds, and other debris between the propellers of a marine propulsion unit having a gear case below the water line. The line collector30protects the seals from stress and caused by the entangled fishing line, etc., thereby reducing wear on the seal and preventing the premature failure of the propulsion unit. Another advantage that may be realized in the practice of some embodiments of the described device is that the line collector30is virtually maintenance free once installed, and the installation of the line collector30is facilitated by its configuration. Yet another advantage that may be realized in the practice of some embodiments of the described device is that the line collector30is easily adaptable to virtually any dual propeller propulsion unit, including outdrive or pod drive propulsion units, and further can also be adapted for use on single propeller propulsion units. Virtually any marine outdrive system with counter-rotating propellers can benefit from the line collector30if it has internal seals.