Weed and Line Cutter Installation Tool

Abstract

The present invention relates to a novel apparatus and method for installing split line cutters on marine propeller shafts. The apparatus features a clamshell design comprising an upper and lower half, each with an inner cavity configured to accommodate a portion of the split line cutter. A hinge mechanism connects these halves, facilitating easy opening and closing around the propeller shaft. Key to this invention is a captive screw retaining mechanism within the clamshell, designed to hold screws in place even when unfastened, thereby simplifying the installation process and preventing loss of components. The apparatus includes a screwdriver opening aligned with a bolt cavity, allowing for engagement of captive screws. Additionally, the invention features temporary closure mechanisms, for secure handling during installation, and a retaining hole for attaching a line. This invention offers significant improvements in the installation of line cutters, emphasizing safety, efficiency, and ease of use.

Claims

1. An installation tool for mounting a split line cutter onto a marine propeller shaft, the split line cutter having an upper portion, a lower portion, and at least one mounting bolt that secures the upper and lower portions around the propeller shaft, the installation tool comprising: (a) a first clamshell half configured to receive at least a portion of the split line cutter, the first clamshell half including a first inner cavity sized and shaped to protect a sharpened edge of the split line cutter; (b) a second clamshell half hingedly coupled to the first clamshell half, the second clamshell half including a second inner cavity sized and shaped to protect another portion of the split line cutter; (c) a retaining mechanism disposed on at least one of the first clamshell half or the second clamshell half, the retaining mechanism being configured to hold the split line cutter portions within the respective inner cavities when the installation tool is in a closed position; (d) one or more bolt cavities formed in at least one of the clamshell halves, each bolt cavity being configured to hold the mounting bolt in a captive position, whereby a driver may engage the mounting bolt through a driver opening in the installation tool; and, (e) a temporary closure mechanism that provides a temporary locking force that retains the installation tool in the closed position, wherein the installation tool is adapted to (i) secure the split line cutter during alignment on the marine propeller shaft, (ii) protect the sharpened edge of the split line cutter, and (iii) allow a user to fasten the mounting bolt without directly contacting the sharpened edge.

2. The installation tool of claim 1, wherein the temporary closure mechanism is a magnetic closure disposed on each of the first and second clamshell halves, the magnetic closure providing a temporary locking force that retains the installation tool in the closed position around the propeller shaft.

3. The installation tool of claim 1, wherein the retaining mechanism comprises a removable plug that extends into a bolt hole of one of the split line cutter portions, and is automatically forced out of the bolt hole upon tightening of the mounting bolt.

4. The installation tool of claim 1, wherein at least one of the first clamshell half or the second clamshell half includes a retaining hole adapted to receive a tether, lanyard, or other securing device, thereby preventing accidental loss of the installation tool in an underwater environment.

5. The installation tool of claim 1, wherein the driver opening is shaped to guide a screwdriver or hex key into engagement with the mounting bolt without requiring direct visual alignment, providing tactile feedback to the user as the mounting bolt is tightened.

6. The installation tool of claim 1, wherein at least one of the first clamshell half or the second clamshell half is formed from a polymeric material that is sufficiently rigid to protect the sharpened edge of the split line cutter and sufficiently low-cost to serve as both packaging and installation aid for the line cutter.

7. The installation tool of claim 1, further comprising an optional safety strap configured to temporarily attach the tool to the propeller shaft, preventing the tool and enclosed line cutter portions from being dropped during installation.

8. The installation tool of claim 1, further comprising the hinged connection being of sufficient rigidity to ensure alignment of the split line cutter.

9. A method for installing a split line cutter onto a marine propeller shaft using an installation tool having first and second clamshell halves hingedly coupled, at least one retaining mechanism, and at least one bolt cavity for a mounting bolt, the method comprising the steps of: a. closing the clamshell halves around the propeller shaft, thereby aligning the split line cutter portions to clamp onto the shaft; b. inserting a driver through at least one driver opening in the installation tool, the driver engaging the mounting bolt residing in the bolt cavity of the installation tool; c. fastening the mounting bolt to secure the upper portion of the split line cutter to the lower portion on the propeller shaft; and d. removing the installation tool by releasing the retaining mechanism after the mounting bolt is sufficiently tightened, whereby the sharpened edge of the split line cutter is protected and the mounting bolts are retained against loss during installation.

10. The method of claim 9, wherein a magnetic closure holds the clamshell halves together during step (c), further comprising the step of detaching the magnetic closure by manually applying force to separate the first and second clamshell halves.

11. The method of claim 8, further comprising the step of attaching a tether or lanyard to the installation tool prior to submerging the tool, such that the tool and the split line cutter portions remain secured to the vessel in an underwater environment.

12. The method of claim 8, wherein the mounting bolt includes a pre-applied locking material retained in place by the bolt cavity, the method further comprising activating the locking material during step (e) to prevent the mounting bolt from loosening under vibration.

13. A kit for installing a split line cutter onto a marine propeller shaft, comprising: (a) a split line cutter including an upper portion, a lower portion, and at least one mounting bolt configured to secure the upper and lower portions around the propeller shaft; (b) an installation tool according to claim 1, wherein the installation tool is sized to house and protect the split line cutter portions during storage and shipping; and (c) instructions describing a procedure for placing the split line cutter portions into the installation tool, aligning the tool on the propeller shaft, and tightening the mounting bolt using the installation tool, wherein the installation tool and the split line cutter are packaged and sold together for convenient, safe, and accurate installation.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0024] For a more complete understanding of the invention, reference is made to the following description and accompanying drawings, in which:

[0025] FIG. 1A Shows a line cutter installed on a propeller shaft;

[0026] FIG. 1B shows a view of the line cutter installed on a propeller shaft, the view being rotated approximately 180 degrees from FIG. 1A;

[0027] FIG. 1C shows a side view of the line cutter installation showing the two halves;

[0028] FIG. 1D shows the needed balancing holes;

[0029] FIG. 1E shows the mounting bolts;

[0030] FIG. 2A shows a top view of one embodiment of the line cutter installation tool;

[0031] FIG. 2B shows an orthogonal view of one embodiment of the line cutter installation tool;

[0032] FIG. 2C shows a side view of one embodiment of the line cutter installation tool;

[0033] FIG. 3 shows a side view of one embodiment showing a cavity for protecting the sharp edge of the line cutter;

[0034] FIG. 4 shows an exploded view showing one embodiment of the retaining mechanism using a plastic plug;

[0035] FIG. 5 shows a view of an embodiment of the installation tool without the line cutter installed; and

[0036] FIG. 6 shows an exploded view of the captive bolt retaining mechanism including a lock washer and adhesive.

DETAILED DESCRIPTION OF THE INVENTION

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.