Weed and Line Cutter Installation Tool

Description

REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of and claims priority under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 63/620,804 filed Jan. 13, 2024 titled “Weed and Line Cutter Installation Tool”.

FIELD OF THE INVENTION

The present invention relates to weed and line cutters installed on recreational and commercial marine vessels and in particular to tools used to install weed and line cutters on recreational marine vessels.

BACKGROUND OF THE INVENTION

Line and weed cutters are sharp instruments installed on the propeller shaft of commercial or recreational marine vessels. When these vessels traverse inland and ocean waterways, long strands of material may wrap around the propeller shaft and stall the engine. This material could man-made material such as rope or fishing line, or it could be natural material such as weeds.

To prevent such an occurrence, a line and weed cutter (referred to as simply a “line cutter”) may be installed on the propeller shaft. There are many different designs of these cutters, but they all share the use of a sharp edge that rotates with the propeller shaft. It uses the power of the rotating shaft to slice through anything that begins to wrap around the shaft.

The line cutter may be for example a simple disc that is concentric with the shaft itself. The edges of the disc are sharpened to make a circular knife. If a rope, line, or weed begins to wrap around the shaft, the pressure of the rope on the shaft will press against the knife-edge and sever the rope, line, or weed.

The installation of these line cutters is normally done with the boat out of the water. Some line cutters require the removal of the propeller, but some line cutters are split and designed to allow installation without removing the propeller.

Because the line cutters by design have sharp knife-like edges, installing them requires great care to avoid cuts or nicks. The sharp edge may have some protective barrier that can be removed during or after installation. This protective barrier may be for example tape or rubber placed over the sharp edge. This protective barrier is not strong enough to prevent damage if the line cutter is dropped, and does not assist with alignment of the cutter if it is of the split type.

While the split type line cutters may be installed without removing the propeller, the presence of the sharp edge makes installing them a task that requires care and dexterity. The two sharp halves need to be held together while the bolts are threaded into the cutters.

It is typical that vessels are removed from the water at a commercial marina, which entails cost of removing and replacing the vessel which would typically be much higher than the cost of the line cutter itself. For this reason the installation of the line cutter is typically done when the boat is removed for other reasons, such as the owner will not be using the boat over the winter.

While the split type of line cutters can be installed underwater, saving the cost of removing the boat from the water, this is not trivial in practice. The protective barrier can be difficult to remove underwater with gloves, as it requires a high degree of dexterity. This entails removing the protective barrier and exposing the sharp edge above water. If part of the line cutter or the bolts are dropped it will be difficult or impossible to recover. Divers may have limited dexterity, especially if wearing gloves due to the cold water.

If a line cutter is being installed underwater by a snorkeler or free-diver, they have limited time that can be spent with each install step. With a typical split line cutter there is a significant risk of the cutter falling off the shaft, as until the bolts are secured the person installing the line cutter must hold it on the shaft. For these reasons even the split type line cutters are normally installed while the vessel is out of the water.

When installing a line cutter with the boat out of the water, a dropped line cutter will not be lost. But the sharp edge will be easily damaged if dropped onto hard ground. The protective layer installed on the sharp edge by the manufacturer is often only to protect the user from the sharp edge, and is not strong enough to protect the sharp edge from the weight of the line cutter being dropped.

What is needed is a tool to install the line cutter and hold captive all parts of the cutter, which protects the sharp edge from both damage and accidental contact, and the tool is only removed once the installation is complete. The tool needs to be self aligning and self holding to allow installation by a diver underwater.

OBJECT OF THE INVENTION

It is an object of this invention to: protect the sharp edge of the line cutter from damage when the line cutter is dropped onto hard ground such as found in typical boat yards, typically asphalt, gravel, or concrete; securely hold a split line cutter onto the shaft during the installation process; and to hold captive parts of the line cutter including the bolts until the installation is complete.

Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification and drawings.

SUMMARY OF THE INVENTION

This invention relates to a split line cutter installation tool designed for mounting line cutters on the shafts of marine propellers on vessels. The tool simplifies the installation process, enhances safety, and ensures a secure fit of the line cutter. The tool has a clamshell design, and is made of a material suitable for the marine environment, while also being a material that is low-cost and suitable for packaging the line cutter itself in.

Key features of the tool include it's split design, a captive screw retaining mechanism with driver guide, an alignment and securing system, the construction from suitable materials for the environment and commercial relevance, and the improved ergonomic and safe handling of the installation tool.

The split design of the tool comprises two halves, often referred to as a clamshell design, which can be opened and closed around the propeller shaft. This split design allows for easy placement and removal of the tool without the need to disassemble other parts of the propeller assembly.

A captive screw retaining mechanism with driver guide is a key feature of this tool. The screws necessary for securing the line cutter to the shaft are retained within the tool itself, even when loosened. This design prevents the loss of screws during installation or removal in challenging marine environments. Openings in the tool provide a guide for the installation screwdriver, allowing installation with no visibility.

The alignment and securing system aligns the line cutter correctly on the shaft, including aligning bolt holes in each half of the shaft. Once aligned, the tool securely holds the line cutter in place while it is being fastened, reducing the risk of misalignment or slippage. An optional safety strap can be temporarily attached to the propeller shaft, which holds the installation tool and line cutter in case it is dropped during installation. The aligning and securing system also holds the line cutter in the tool itself, to ensure the line cutter is not dropped when opening and closing the tool.

The material and durability is important for both the marine environment and the commercial use. The tool may be sold with the line cutter, which requires consideration for the cost of the installation tool. As the user may wish to reuse the tool for future removal or storage of the cutter, the tool must be constructed of a material which meets both the cost requirements, along with withstanding typical marine environments.

The tool is designed with ergonomics in mind, making it easy and safe to handle, even on wet or slippery decks. This feature reduces the risk of accidents during the installation process, which may result in damage or loss of the tool and line cutter, or harm to the installer.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the apparatus embodying features of construction, combinations of elements and arrangement of parts that are adapted to affect such steps, all is exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

BRIEF DESCRIPTION OF DRAWINGS

For a more complete understanding of the invention, reference is made to the following description and accompanying drawings, in which:

FIG. 1A Shows a line cutter installed on a propeller shaft;

FIG. 1B shows a view of the line cutter installed on a propeller shaft, the view being rotated approximately 180 degrees from FIG. 1A;

FIG. 1C shows a side view of the line cutter installation showing the two halves;

FIG. 1D shows the needed balancing holes;

FIG. 1E shows the mounting bolts;

FIG. 2A shows a top view of one embodiment of the line cutter installation tool;

FIG. 2B shows an orthogonal view of one embodiment of the line cutter installation tool;

FIG. 2C shows a side view of one embodiment of the line cutter installation tool;

FIG. 3 shows a side view of one embodiment showing a cavity for protecting the sharp edge of the line cutter;

FIG. 4 shows an exploded view showing one embodiment of the retaining mechanism using a plastic plug;

FIG. 5 shows a view of an embodiment of the installation tool without the line cutter installed; and

FIG. 6 shows an exploded view of the captive bolt retaining mechanism including a lock washer and adhesive.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1A-1E show different views of a typical split line cutter installed on a propeller shaft 101. FIG. 1A shows the installation on the propeller shaft 101, and FIG. 1B shows a view of this installation from the other side of the propeller shaft 101. FIG. 1C shows that the line cutter is split into an upper 106 and lower 107 portion. The line cutter has a sharp edge 102 with an angled section 105 to provide support for the sharp edge 102, and allow for future sharpening of sharp edge 102. FIG. 1A shows that the line cutter has a larger hub portion 103 which allows mounting bolts shown in FIG. 1E as 104 to secure the upper 106 and lower 107 portion together, clamping around the propeller shaft 101.

The mounting bolts 104 will typically be a socket head type, which use a hex screwdriver (often referred to as an Allen key). The mounting bolts 104 will have some form of locking to prevent the bolts from backing out due to vibration. This might include a locking material on the bolt thread such as a glue or rubber, or mechanical means to hold the bolt secure such as a lock washer, a locking cable, or another bolt that threads into or against the mounting bolts 104.

The mounting bolt countersink 108 causes the upper 106 and lower 107 half of the split line cutter to be different weights and thus unbalanced, which may lead to vibrations at higher propeller speeds. As shown in FIG. 1D to prevent this balancing holes 109 can be drilled in the lower 107 half of the split line cutter. Additionally threaded holes 110 may be added to the upper 106 and lower 107 portions for a locking set screw to be used to further lock the line cutter onto the shaft.

FIG. 2A-FIG. 2C show different views of one embodiment of the installation tool for the split line cutter. FIG. 2A shows how the upper 106 and lower 107 portion of the split line cutter present in each part of the installation tool. Further figures will show the tool alone (without upper 106 and lower 107 portion present) along with the tool used during the installation itself.

FIG. 2B shows the tool has two clamshell halves, an upper clamshell half 201 and a lower clamshell half 202. A hinge point 203 allows the two halves to open. A retaining mechanism 211 holds each half of the line cutter in the clamshell. The retaining mechanism 211 in this embodiment is a wingbolt, but other mechanisms such as friction fit of the clamshells, adhesives, thumbscrews, bolts, and plastic plugs are all similarly suitable for the purpose of retaining each of the upper 106 and lower 107 sections of the line cutter in the upper clamshell half 201 and lower clamshell half 202 section of the clamshell.

During installation, the upper clamshell half 201 and a lower clamshell half 202 need to be held together temporarily using a temporary closure mechanism. Several embodiments of this mechanism are demonstrated in FIG. 2B, and the tool may include only a single or multiple types of temporarily closure mechanisms. One embodiment is to use a magnet 204 which are installed on both the upper clamshell half 201 and a lower clamshell half 202. The magnets are oriented such they will have a strong attractive force, and this is especially effective if a rare-earth magnet such as a neodymium magnet is used. The user can close the tool around the propeller drive shaft, and it will securely stay shut to complete the installation process.

Another embodiment of the temporary closure mechanism is the holes 205 present in the upper clamshell half 201 and a lower clamshell half 202. These holes allow a suitably shaped fork or plug to be inserted, which will hold the two sides closed. The holes may also be used to pass a string or line through, which can be used to either hold the tool closed or to secure the tool to prevent it from being dropped. Finally the protrusion 206 is designed to be held by hand, which allows one to hold the mechanism closed with a single hand. This same protrusion 206 also serves as a stop for a line, string, rubber band, or zip-tie which could be passed over the end of the tool. This will allow the tool to be securely closed, and the protrusion 206 prevents the line, string, rubber band, or zip-tie from falling off the end of the tool.

During installation, there is a risk the tool is dropped. This is especially the case if the line cutter is being installed underwater. For this purpose a retaining hole 212 is included. A line, chain, string, or rope can be attached to the retaining hole 212. Because the line cutter halves are secure to the tool using the retaining mechanism 211, this single retaining hole 212 allows both the tool and line cutter to be secured from the attached line, chain, string, or rope. During the installation process the lanyard or retaining hole 212 allows the installation tool to be temporarily attached to the vessel, by being clipped to any conveniently available protrusion from the vessel. This could include for example a hook or wire attached to the driveshaft itself.

The inclusion of the retaining hole 212 allows the installation of the line cutter to occur when the process must be interrupted, such as would occur if the installation is happening using only a mask and snorkel. In this example the installation tool may first be attached to a lanyard by the retaining hole 212 which is passed over a hand, to ensure the item is not dropped. The lanyard is then transferred to the vessel itself. Once the installation is complete and the tool is to be removed, the lanyard is then removed from the vessel.

During installation, the upper clamshell half 201 and a lower clamshell half 202 are closed around a propeller drive shaft. the retaining mechanism holds the two halves closed as discussed. Previously in the installed line cutter from FIG. 1C, the mounting bolts 104 can be seen securing the line cutter to the drive shaft. In FIG. 2B, the mounting bolts are not yet installed, and are marked as the captive mounting bolts 208. The bolts are held captive by a bolt cavity 209, which is part of the upper clamshell half 201.

The construction of the hinge 203 ensures that on closure the two halves are correctly aligned, and the captive mounting bolts 208 will thread into the lower 107 section of the line cutter. This will clamp the upper 106 and lower 107 sections of the line cutter onto the drive shaft. To allow tightening of the captive mounting bolts 208, a screwdriver opening 210 allows the appropriate screwdriver to pass through and engage with the captive mounting bolts 208. Typically this would be a hex or ball-head hex screwdriver as used by captive screws which are shown in FIG. 2B and FIG. 2C, but those skilled in the art will recognize there are many forms of screwdrivers and bolt heads.

The screwdriver opening 210 in combination with the bolt cavity 209 also ensure that the bolt can be screwed in without visually seeing the screw head. The recessed screwdriver opening 210 can be made of the size such a screwdriver will fit through and engage the captive mounting bolts 208, and this can be felt as a positive engagement when using a hand tool. The screwdriver opening 210 may have additional design for improved tactile feedback, such as having a sloped funnel shape to guide the screwdriver into the screwdriver opening 210, or having a built-up cylinder around the screwdriver opening 210 to raise it above the height of the body of the tool.

Once the captive mounting bolts 208 hold the upper 106 and lower 107 half of the split line cutter together, the installation tool can be removed. This can be done once the mounting bolts are fully tightened and the line cutter cannot move, or can be done before they are fully tightened. Depending on the installation for example it may be easier to access bolts from certain angles, and it is desired to have the ability to move the line cutter on the propeller shaft after the installation tool is removed. The installation tool is removed by removing the retaining mechanism 211, in the embodiment of FIG. 2B this would mean removing the wingbolt.

FIG. 3 shows another side view of the tool, with the sharp edge 102 of the line cutter marked. The clamshell inner cavity 301 is designed to protect the sharp edge 102, by providing some clearance from the sharp edge 102 and clamshell inner cavity 301. The clamshell inner cavity 301 may be designed to rest on the angled section 105 of the line cutter, which in combination with a choice of a slightly flexible material for the tool provides a friction fit of the half of the line cutter in the clamshell. This may be used in place of or in addition to the previous embodiment of a retaining mechanism 211 that held the line cutter in the clamshell with a threaded wingbolt.

Another embodiment of a retaining mechanism is shown in FIG. 4, where a plastic plug 401 that may be a separate part that is inserted into a suitable hole in the lower clamshell half 202, or may be made an integral part of the lower clamshell half 202, extends into the lower 107 half of the line cutter bolt hole 402. In this design as the captive mounting bolts 208 are tightened, the plastic plug 401 is forced out of the lower 107 half of the line cutter. If the plastic plug 401 is a separate item inserted into the lower clamshell 202 this will ensure that the retaining mechanism is automatically released once the captive mounting bolts 208 begin to be tightened. The two clamshell halves will still be held together by the temporary retaining mechanism. If the plastic plug 401 is an integral part of the lower clamshell half 202, this will also force open the lower clamshell half 202, again releasing the tool from the line cutter, while also releasing the temporary retaining mechanism. These provide two different user experiences and may be further optimized for different use-cases and installation procedures.

A view of the installation tool without the line cutter installed is given in FIG. 5. Here again the upper clamshell half 201 and lower clamshell half 202 are joined by a hinge 203. The clamshell inner cavity 301 is visible.

The material for the installation tool will depend on the specific use-case and commercial marketing plan. If the tool is sold with a line cutter, a low-cost and lightweight material such as a plastic may be preferred. Such a material provides a simple method of safely shipping the line cutter to the end customer, as the sharp edge is prevented from being exposed. The sharp edge is also protected from damage in the event the line cutter is dropped, and there is no risk of the line cutter being damaged when being transferred to a different installation tool. The installation tool can also be made from techniques such as 3D printing, which allows rapid stocking of tools with varying dimensions to suit line cutters coming from many vendors.

If the installation tool is to be used commercially, a more robust material such as stainless steel my be preferred instead of a plastic material. This has advantages of a more precise and rigid design, which will improve the ability of the tool to align the mounting bolt holes. This would be considerably more expensive than a simple plastic model, and would not be suitable for use as a low-cost shipping container.

The installation tool may also have transparent sections, using a transparent material or openings along the tool. This can assist with the installation by providing a method of ensuring the line cutter is correctly aligned before tightening.

Further modifications to the design to assist with alignment can be made to ensure the line cutter is a correct distance from the other sections of the driveshaft, such as a bearing or hub. This can be done with markings on the installation tool, or by modifying the design of the installation tool to include spacers or open sections.

FIG. 6 shows an exploded view of the upper clamshell half 201 with the upper 106 cutter section, and the captive mounting bolts 208. The design of the cutter with captive bolt cavity 209 also makes it simple to add the required bolt locking mechanisms that will prevent the captive mounting bolts 208 from coming loose due to vibration or rotation of the line cutter. A lock washer 601 is added to the captive mounting bolts 208, and because the captive mounting bolts 208 are held securely between the captive bolt cavity 209 and upper 106 cutter section, these lock washer 601 cannot be accidentally dropped during shipping or installation. Other bolt locking mechanisms are also compatible with the captive bolt cavity 209, such as using a locking fluid 602, which may be for example some form of plastic, rubber, or adhesive. Normally the locking fluid 602 would be placed on the bolt only before installation of the bolt, but because the bolt is protected within the captive bolt cavity 209 the locking fluid 602 can be installed by the manufacturer. This demonstrates another advantage of the line cutter installation tool holding all parts of the line cutter together until it is installed.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, because certain changes may be made in carrying out the above method and in the construction(s) set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.