DESC:FIELD OF THE INVENTION:
This invention relates to the field of marine engineering.

Particularly, this invention relates a mooring winch.

Specifically, this invention relates to a mooring winch with in-built safety mechanism.

BACKGROUND OF THE INVENTION:
A mooring refers to any permanent structure to which a vessel may be secured. Examples include quays, wharfs, jetties, piers, anchor buoys, and mooring buoys. A ship is secured to a mooring to forestall free movement of the ship on the water. An anchor mooring fixes a vessel's position relative to a point on the bottom of a waterway without connecting the vessel to shore. Mooring, also refers to the act of attaching a vessel to a mooring.

Mooring winch perform multitude of functions. They secure the shipboard end to mooring lines, provide for adjustment of the mooring line length to suit the mooring pattern in each port and compensate for changes in draft and tide.

Winches can be categorized by their control type (automatic or manual tensioning). In marine engineering, a both automatic and manual mooring winch brake tightening process is followed. This invention is related to manual mooring winch brake tightening process.

Manual mooring winch brakes are used to hold mooring ropes which secure a ship at a pier or elsewhere to limit her movement. A typical arrangement of various mooring lines likes head line, forward breast line, etc. to secure a tanker at its berth is shown in Figure 1 of the accompanying drawings.

Reference numeral 10 refers to a head line.
Reference numeral 12 refers to a forward breast line.
Reference numeral 14 refers to a forward spring.
Reference numeral 16 refers to an aft spring
Reference numeral 18 refers to an aft breast line.
Reference numeral 20 refers to stern lines.

A common arrangement of linkages in manual mooring winch brake is shown in Figure 2 of the accompanying drawings.

Double shoe brake linings are used in manual mooring winch brake. These brake liners are screwed to the semicircular linkages (22) with the help of special countersunk screws. These semi-circular linkages are clearly marked. These linkages can pivot about a fulcrum point (26). When the brake hand wheel (20) is rotated, threaded portion of the shaft (28) rotates in a fixed block on the mooring winch. This, in turn, generates forward motion of brake hand wheel (20). The linkages’ (22) arrangement is such that semicircular brake liners (23) are tightened against a brake drum (21). This brake drum (21) is mounted on the same shaft (28) on which the mooring lines are passed and secured. This is how the manual mooring winch brakes are used to tighten the mooring ropes. Reference numeral 24 refers to fixed point attached to foundation.

Figure 3 illustrates markings on a mooring winch for optimum tightening.

Reference numeral 35 indicates black marking. Black marking (35) is on a plate attached to said linkage/s (22) of mooring winch. The black marking (35) location is decided by doing a Brake Rendering Capacity (BRC) test. BRC test is a standard test that needs to be done on mooring winch at least once a year. This test sets the tightening limit on the brakes so that the tension on mooring rope, of the mooring winch, is about 60% (or a pre-determined percentage) of its breaking capacity.

Reference numeral 37 indicated red marking on said hand wheel shaft (28). Red marking is provided by equipment manufacturer (Mooring winch manufacturer).

In manual mooring winch brakes, it is essential to tighten mooring ropes as per the markings shown in Figure 3. When brake hand wheel is angularly displaced; red marking (37) on the threaded portion of handle shaft moves forward. Standard operating procedure for mooring winch brake specifies that when this red marking (37) matches the black marking (35); tightening of mooring rope should be stopped. This is the recommended optimum tightening of brakes which introduces optimum tension in the mooring rope. Black color marking is designed such that tension in the rope is limited to about 60% of its breaking load. There are incidences which report that ship crew staff member does not follow the black marking on the brake. This may result in under-tightening or over-tightening of the mooring ropes. Under-tightening or over-tightening can result in below mentioned problems:
1. Under tightening will make the brake to give in more mooring rope when wind or wave loads come on the ship. This can also create difficulty in holding the ship at port. Also in case of ship to ship operations, the transfer of cargo won’t be smooth.
2. On the contrary to under tightening, In case of excessive loads on the ship due to the reasons mentioned above, over tightening increases the tension load in the mooring ropes as this will not render even in extreme conditions. This increased tension in the rope may results in sudden breakage of mooring lines causing accidents. The extent of this accident may be up to fatal injury and also undesirable movement of ship causing damages to adjacent ships. Mooring rope failures may cause heavy economic losses due to time loss resulting from accidents and fixing up the failed ropes.

There is a need for a design which ensures optimum tightening of mooring ropes without any manual interference. In terms of operations, red marking on the screw will match the black arrow and further tightening is not possible.

OBJECTS OF THE INVENTION:
An object of the invention is to provide a mooring winch with in-built safety mechanism such that optimum tightening of mooring rope is achieved, automatically.

Another object of the invention is to provide a mooring winch with in-built safety mechanism such that both, under-tightening of the mooring rope as well as over-tightening of the mooring rope, are avoided.

Yet another object of the invention is to provide a mooring winch such that, in terms of operations, red marking matches black marking and further tightening is not possible, at all, by the mooring winch even if tried.

SUMMARY OF THE INVENTION:
According to this invention, there is provided a mooring winch with in-built safety mechanism comprising:
- a cam and plunger mechanism, mounted in line with and in communication with a brake hand wheel shaft, said cam and plunger mechanism configured to work on a principal similar to a torque wrench wherein,
i. a first side of said brake hand wheel shaft is attached to a brake hand wheel (49) handle;
ii. a second side of said brake hand wheel shaft is attached to a hollow shaft (61), said hollow shaft houses a cam shaft;
- a pipe welded to said hollow shaft which houses a plunger, having a resilient element, on its operative top;
- a setting screw provided at an operative top of said pipe to adjust resilient (spring) force on said plunger, said plunger being positively locked between consecutive teeth of said cam shaft to transfer motion of said brake hand wheel to said second side of said brake hand wheel shaft such that,
a. as long as said resilient (spring) force on said plunger is above a set limit, a positive transfer of motion takes place; and
b. after set tightening of brakes against a brake drum, said plunger overcomes said resilient (spring) force and slippage in said mechanism – thereby, preventing over tightening of said brakes.

Typically, said setting screw is configured such that slippage occurs when a red marking, on said hand wheel shaft provided by a mooring winch manufacturer, matches a black marking on a plate attached to a linkage of said mooring winch, said black marking being determined by a Brake Rendering Capacity (BRC) test done on said mooring winch, periodically.

Typically, said first side of said brake hand wheel shaft is attached to said brake hand wheel (49) handle via a shaft (51).

Typically, said second side of said brake hand wheel shaft is a lead screw side which is attached to said hollow shaft.

Preferably, said hollow shaft houses all associated bearings.

Preferably, said cam shaft is fastened with the help of a key as shown in section (A-A);

Preferably, said plunger is a locking plunger.

Preferably, said resilient element is a compression spring.

Typically, said brake hand wheel shaft is cut at the unthreaded shaft portion.

Typically, said cam and plunger mechanism is mounted on said brake hand wheel with the help of flanges and bolts.

Typically, a setting screw in said cam and plunger mechanism is adjusted such that said brake hand wheel slips when red marking on said hand wheel shaft matches a black marking on a mooring winch.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
Figure 1 illustrates a typical tanker mooring at a tanker berth.

Figure 2 illustrates a manual mooring winch brake linkages arrangement.

Figure 3 illustrates markings on a mooring winch for optimum tightening.

The invention will now be described in relation to the accompanying drawings, in which:

Figure 4 illustrates a cam and plunger attachment mounted on brake hand wheel rod; and

Figure 5 illustrates a cross-section view of a cam and plunger attachment.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
According to this invention, there is provided a mooring winch with in-built safety mechanism.

Figure 4 illustrates a cam and plunger attachment mounted on brake hand wheel rod.

Figure 5 illustrates a cross-section view of a cam and plunger attachment.

In at least an embodiment of this invention, a cam and plunger mechanism (100) is mounted on brake hand wheel shaft (28), in line with the shaft (28), which works on the principal similar to torque wrench. One side of the brake hand wheel shaft (28) is attached to the brake hand wheel (49) handle via a shaft (51); a cam type shaft is fastened with the help of key as shown in cross section A-A in figure 6. Other side of the brake hand wheel shaft (28) which is named as lead screw side (52) is attached to a hollow shaft with the help of bolt. This hollow shaft houses the cam shaft and all the associated bearings (53). A pipe is welded to the hollow shaft which houses a plunger (54), which is a locking plunger, having a resilient element (55), such as a compression spring, on its top. A setting screw (56) is provided at the top of the pipe to adjust the resilience (spring) force on the plunger (54). The plunger (54) is positively locked between consecutive teeth of cam type shaft to transfer motion of brake hand wheel (49) to the lead screw side (52) of the shaft. As long as the resilient (spring) force on the plunger (54) is above the set limit, a positive transfer of motion will take place. After set tightening of brakes (23), the plunger (54) overcomes the resilient (spring) force and slippage in the mechanism occurs; thereby, preventing additional tightening. Here, the setting screw (56) is adjusted such that slippage occurs when the red marking (37) matches the black marking (35). Reference numeral 57 refers to bearing bush. Reference numeral 58 refers to shaft bush. Reference numeral 59 refers to locking bush.

In at least an embodiment, the brake hand wheel shaft is cut at the unthreaded shaft portion.

In at least an embodiment, the cam and plunger attachment is mounted on the brake hand wheel (49) with the help of flanges and bolts.

In at least an embodiment, the setting screw (56) in the cam and plunger mechanism (100) is adjusted such that brake hand wheel (49) slips when red marking (37) on the hand wheel shaft (28) matches the black marking (35) as discussed earlier. Black marking (35) on the mooring winch is set using brake rendering capacity (BRC) test. This is a standard test carried out on mooring winch brakes once or twice a year.

Once this attachment is installed, calibration is done using a hydraulic jack pressure reading in BRC test. Thus, black marking in the prior art arrangement is replaced by a set screw in the cam and plunger mechanism.

In at least a non-limiting exemplary embodiment, this invention was tested on a vessel ‘M V Chola Harmony’. The device of this invention was fitted on a brake handle for aft starboard mooring winch. As for springs supplied, the red colored spring was used to calibrate and match with the brake rendering point, as stated in the description above. The device could meet the desired outcome and it enhanced the safety of mooring operations. The device of this invention was able to tighten the brakes to a set torque and then slipped. Thus, it prevented overloading of mooring ropes.

The TECHNICAL ADVANCEMENT of this invention lies in providing a mechanical arrangement which sets tension in mooring ropes while mooring to the exact required tension (without under-tensioning and without over-tensioning) in a manual mode, yet without requiring human judgment or without requiring precise actions, as such.

While considerable emphasis has been placed herein on the particular features of this invention, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiments without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.
,CLAIMS:WE CLAIM,

1. A mooring winch with an in-built safety mechanism comprising:
- a cam and plunger mechanism (100), mounted in line with and in communication with a brake hand wheel shaft (28), said cam and plunger mechanism (100) configured to work on a principal similar to a torque wrench wherein,
i. a first side of said brake hand wheel shaft (28) is attached to a brake hand wheel (49) handle;
ii. a second side of said brake hand wheel shaft (28) is attached to a hollow shaft (61), said hollow shaft houses a cam shaft (60);
- a pipe (62) welded to said hollow shaft which houses a plunger (54), having a resilient element (55), on its operative top;
- a setting screw (56) provided at an operative top of said pipe to adjust resilient (spring) force on said plunger (54), said plunger (54) being positively locked between consecutive teeth of said cam shaft to transfer motion of said brake hand wheel (49) to said second side of said brake hand wheel shaft (28) such that,
a. as long as said resilient (spring) force on said plunger (54) is above a set limit, a positive transfer of motion takes place; and
b. after set tightening of brakes (23) against a brake drum (21), said plunger (54) overcomes said resilient (spring) force and slippage in said mechanism – thereby, preventing over tightening of said brakes (23).

2. The mooring winch with in-built safety mechanism as claimed in claim 1 wherein, said setting screw (56) being configured such that slippage occurs when a red marking (37), on said hand wheel shaft provided by a mooring winch manufacturer, matches a black marking (35) on a plate attached to a linkage (22) of said mooring winch, said black marking (35) being determined by a Brake Rendering Capacity (BRC) test done on said mooring winch, periodically.

3. The mooring winch with in-built safety mechanism as claimed in claim 1 wherein, said first side of said brake hand wheel shaft (28) is attached to said brake hand wheel (49) handle via a shaft (51).

4. The mooring winch with in-built safety mechanism as claimed in claim 1 wherein, said second side of said brake hand wheel shaft (28) is a lead screw side (52) which is attached to said hollow shaft.

5. The mooring winch with in-built safety mechanism as claimed in claim 1 wherein, said hollow shaft houses all associated bearings (53).

6. The mooring winch with in-built safety mechanism as claimed in claim 1 wherein, said cam shaft being fastened with the help of a key (63) as shown in section (A-A);

7. The mooring winch with in-built safety mechanism as claimed in claim 1 wherein, said plunger (54) is a locking plunger.

8. The mooring winch with in-built safety mechanism as claimed in claim 1 wherein, said resilient element (55) is a compression spring.

9. The mooring winch with in-built safety mechanism as claimed in claim 1 wherein, said brake hand wheel shaft (28) is cut at the unthreaded shaft portion.

10. The mooring winch with in-built safety mechanism as claimed in claim 1 wherein, said cam and plunger mechanism (100) is mounted on said brake hand wheel (49) with the help of flanges and bolts.

11. The mooring winch with in-built safety mechanism as claimed in claim 1 wherein, a setting screw (56) in said cam and plunger mechanism (100) is adjusted such that said brake hand wheel (49) slips when red marking (37) on said hand wheel shaft (28) matches a black marking (35) on a mooring winch.

Dated, this 30th day of April, 2020

CHIRAG TANNA
OF INK IDÉE
APPLICANT’S PATENT AGENT