WO2005049474A1

WO2005049474A1 - Davit winch with oil brake

Info

Publication number: WO2005049474A1
Application number: PCT/HR2004/000057
Authority: WO
Inventors: Tonci Zanetic
Original assignee: Tonci Zanetic
Priority date: 2003-11-24
Filing date: 2004-11-22
Publication date: 2005-06-02

Abstract

The davit winch with oil brake, housed in the tight casing (14), and consists of the inner drum (17) and the outer drum (16), firmly fixed to the gears (12), the lamella (7) firmly fixed to the outer and the inner drums, the ring (18), the drum (11) firmly fixed to the gears (12), the shoes (9) loosely fixed to the drum (11), and the pushing bolts (8), via which, due to the centrifugal force created at lowering of the boat and turning of the gears (12), the shoes, via the ring (18), press the lamellas, this resulting in friction between the lamellas and, thus, the controlled breaking or lowering of the boat. All system parts are permanently immersed in oil and there is no corrosion, unlike the existing systems that all operate dry. Lowering of the boat suffices to rise the lever (1) with the weight (2) that, via the pushing bolt (10), releases the lamellas (7). Hoisting of the boat is performed by motor, where the stop brake allows rotation of the axle only in the boat hoisting direction.

Description

DAVIT WINCH WITH OIL BRAKE

INVENTION DESCRIPTION

1. FIELD OF APPLICATION

The invention relates to winch intended for hoisting and lowering of lifeboats on ships. This is being performed by various types of davits, the basic device of which is the winch for hoisting and lowering of boats. Presently, it is irreplaceable on passenger ships.

In the International Patent Classification, the patent belongs to Section B - Performing operations; Transporting, Subclass B 63 B - Equipment for shipping, Group 23/00 - Equipment for handling lifeboats or the like, Subgroup 23/40 - Use of lowering or hoisting gear, or Subgroup 23/48 - Using winches for boat handling. The invention also belongs to Class B 66 - Hoisting; Lifting; Hauling, Subclass B 66 D - Winches, Group 1/00 - Rope, cable or chain winding mechanisms, or Subgroup 1/08 - Incorporating fluid motors.

2. TECHNICAL PROBLEM

Under the SOLAS 1974/83 and 92 International Convention, and the IMO 689 Resolution, the life-boat lowering speed is defined exactly by the equation V = 0.4 + 0.02H, where V is the lowering speed in m/sec, and H is the height from the lifeboat boarding deck to the sea surface in m.

Since, by the above mentioned regulations, boats are not lowered empty but with their crew and passengers onboard, the breaking and lowering speed controlling device is to be safe so that people, in case of a ship's average or another accident, are saved safely by lifeboats. 3. STATE OF THE ART

On board the present vessels, davits are equipped with winches that lower, stop and bring the boat to the embarkation deck, and that control the boat lowering speed. The basic device that performs these functions is the breaking system with centrifugal brake, whose ferode-made shoes brake by dry friction in special casings. The greatest problem of this system is the corrosion, particularly intensive at sea. Corrosion results from condensation or possible entering of the sea into the break casing which, because of the way of breaking, cannot be lubricated. Corrosion causes often problems because the entire device or its particular elements jam, this making the boat lowering impossible or its lowering speed too great, wherefore the boat hits the sea surface at a great speed, this in turn jeopardising the people's health and safety.

4. DISCLOSURE OF THE INVENTION

The essence of the invention is the davit winch with oil break that breaks by lamellas made of steel and sintered bronze and that is, with other breaking system elements, immersed into oil, producing wet friction. This way, the entire boat lowering break and speed control mechanism is protected from corrosion, whereby its errors and stoppages are reduced to minimum and the safety of salvage is ensured.

5. ILLUSTRATION DESCRIPTIONS

Figure 1. shows the winch with break casing - front view.

Figure 2. shows the winch with oil break - partial cross-section B-E through the break casing.

Figure 3. shows the winch break with partial cross-section through the break casing. 6. DETAILED DESCRIPTION OF ONE OF THE BEST INVENTION EMBODIMENTS

The davit winch with oil brake, as shown in Figs. 1, 2. and 3., consists of the winch casing 13 to which there are mounted drums 26 winding the rope on which the lifeboat hangs. In the winch casing there are gears 23, 24, 25 and 12, transmitting the power from the motor 28 to the drums 26 at hoisting the boat, or from the motor to the breaking system at lowering the boat. To the winch casing 13 there is firmly fixed the breaking system casing 14. In the casing 14 there is the oil break comprising: outer drum 16, inner drum 17, lamellas

7, ring 18, drum 11, shoes 9, and pushing bolts 8 with return springs that press the lamellas at centrifugal breaking during lowering of the lifeboat. The oil break is firmly fixed, by the inner drum 17 and the drum 11 , to the gears 12 that transmit the power to the gears 23, 24 and 25, in the winch casing 13, turning the drums 26 on which the boat hangs. The outer drum 16 is connected to the gears 6, powered, via the gears 5 and the axle 27, by the boat hoisting motor 28. At the outer front side of the casing 14, there is fitted the manual breaking and boat lowering system, consisting of the lever 1 with weight 2, console 19, connecting element 20, pushing bolt 10 and ring 21. The axle 27 passes through the stop breaks 3 and 4 that act only one way, i.e., allow turning the axle only in the boat hoisting direction and preventing it from turning in the boat lowering direction. To the axle 27, at the outer side of the casing 14, there is fitted the handle 29 for manual hoisting of the boat in case of need. The winch casing 13 and the oil break casing 14 are made tight and contain enough oil to lubricate parts of the mechanisms. All system parts are permanently dipped into oil and there is no corrosion.

Boat is hoisted by the motor 28 (electric or hydraulic), whose power is transmitted via axle 27, gears 5 and 6, and parts of the oil break 16, 7, 18 and 17, to the gears 12, and via gears 23, 24 and 25 to the drums 26. The gravity moment, created on the rope on which the boat hangs is, at lowering of the boat, transmitted via the gears 23, 24, 25 and 12 to the breaking system, where the shoe 9, by centrifugal force, automatically controls the boat lowering speed. The winch drums 26 are made in welded steel, and on them there is winded the steel rope that hoists the boat, in up to three layers.

A resting boat, while hung on ropes, is held by the stop break 3 and 4 that acts in one direction only, allowing turning in the hoisting direction and preventing in the lowering direction. The oil break is on at that moment since it is subjected to the force produced by the weight 2 which, via lever 1, pushing bolt 10 and drum 11, presses the oii-break lamellas. Lowering of the boat requires lifting of the weight 2, in the direction of the arrow (Fig. 1.), i.e., anticlockwise, until the drum 11 leans against the ring 21. This way, via the pushing bolt 10 and the drum 11, the oil- break lamellas are released from pressure and start gliding, which means that the outer part of the clutch 16 rests whereas the inner part 17 rotates, pulled by the weight of the boat. Jointly with the inner part of the oil break 17, there also rotates the drum 11. The gravity of the boat increases the lowering speed, thus also the number of revolutions of the inner drum 17 and the drum 11. Resulting from increase of revolutions of the drum 11 , the centrifugal force (Fc) turns the shoes 9 that, via the bolt 8 and the ring 18, press the lamellas 7. The pressure of the ring 18 against the lamellas cause the system to break, since the outer part 16, via the gears 5 and 6, is blocked by the stop break 3 and 4.

Acting of the centrifugal force (Fc) to the oil break and friction of the lamellas, results in balance of the friction and the centrifugal forces, caused by the weight of the boat, thus controlling the speed of the boat lowering. The lowering speed, set by regulations, is determined at constructing the winch for a certain ship and its testing, and can be changed and regulated in various ways, from changing the weight and shape of the shoes 9, to the number and size of the lamellas in the oil break.

The boat is stopped by releasing the lever 1 and the weight 2 that will, via the pushing bolt 10, press the oil-break lamellas 7 and, thus, stop the lowering. To hoist the boat, the motor 28 is to be started, which motor rotates only in the boat hoisting direction since the stop break 3 and 4 does not allow otherwise, and the boat is being hoisted as long as the motor is switched on. Since, at lowering of the boat, friction of the oil-break lamellas produce heat, the lubrication oil also cools the break.

7. INVENTION APPLICATION

The invention application is evident from its very description. The winch with oil break enables the davits, because of the way of lubrication and the material of which the lamellas are made (steel and sintered bronze), to be used safely and long, as well as easy lowering of the lifeboats. Replacing of the dry-friction breaking system with a wet, i.e., lubricated, one, makes the entire system safer and cheaper in exploitation, since its maintenance is minimised.

Claims

PATENT CLAIMS

1. The davit winch with oil break, consisting of the winch casing (13) with the drums (26), on which there is wound the steel rope, the gears (12, 23, 24 and 25) for transmitting the power of the boat hoisting electric or hydraulic motor (29), and the breaking and boat lowering speed controlling system, wh e rein , it has the tight casing (14), firmly fitted to the winch casing (13); in the casing (14), holding oil, there is the oil break consisting of the inner drum (17) firmly fixed to the gears (12), the outer drum (16) firmly fixed to the gears (6), the lamellas (7) firmly fixed to the outer and the inner drums, the ring (18) leaning against the lamellas, the drum (11) firmly fixed to the gears (12), the shoes (9) loosely fixed to the drum (11), and pushing bolts (8) through the drum (11) via which, due to the centrifugal force created at lowering the boat and turning of the gears (12), the shoes (9) via the ring (18) press the lamellas (7), this in turn causing friction between the lamellas, thus regulating the breaking and lowering of the boat.

2. The davit winch, as claimed in Claim 1., wh e re in at the outer side of the casing (14) there is the lever (1) with the weight (2) that, at activating the lifeboat lowering winch, turn anticlockwise, where the pushing bolt (10) pulls the drum (11) to the ring (21), terminating thus the pressure of the pushing bolts (8), via the ring (18), to the oil-break lamellas (7).

3. The davit winch, as claimed in Claims 1. and 2., that for boat hoisting utilises an electric or hydraulic powering (28), wh erein via the axle (27) and the gears (5 and 6) rotates the gears (12) which, via the gears (23, 24 and 25) rotates the drums (26) that hold the rope on which the boat hangs.

4. The davit winch,. as claimed in Claims 1., 2. and 3., wh erein the resting boat, hung on ropes, is held still by the stop break (3 and 4) that acts in one direction only, allowing turning of the axle (27) in the boat hoisting direction and preventing its turning in the lowering direction, this because of the force of the weight (2) that, via the lever (1), the pushing bolt (10) and the drum (11), presses the oil-break lamellas (7).