FI77621B - ANORDING FOER AUTOMATISK AVLAOSNING AV EN BOGSERHAKE HOS FARTYG. - Google Patents

Description

77621

Automatic towbar release device for ships

TECHNICAL FIELD This invention relates to shipbuilding, and more particularly to automatic towing hook release devices.

Description of the Related Art

Tugboats often capsize in cramped conditions in port areas, mainly as they attempt to turn the tow rope and at a certain angle to the towing direction. When the two vessels are oblique to each other and connected to each other by a rigid tow rope and provided that tow winches are not used for this purpose, a sharp jerk will inevitably occur in the tow rope and this will usually cause the deck of the vessel to fill with water or even capsize.

There are provisions for the required stability of a tug to avoid a fall, but such provisions cannot take into account all towing conditions and thus make the tug safe in all kinds of situations. This can only be achieved by using automatic release devices on the ship's towing hooks, the use of which is constantly increasing in tugs.

The previously known devices for the automatic removal of towing hooks can be roughly divided into two groups. The first group includes devices in which the towing hook lock opens when the tug reaches a certain critical tilt angle. Captain A.A. is already known. A device proposed by Dikin (cf. SU Inventor's Certificate 115,789) that has been widely used for this purpose in the Soviet Union.

The Knilf system, developed by Motorenfabrik Heinrich Liesen from the Federal Republic of Germany, is also known. This system includes two mercury switches that close the circuit when the ship is heeling and turn on a solenoid valve 35 that lets air into the working cylinder. The piston rod pushes the linkage, which opens the towbar lock.

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The same group includes an automatic towbar release device according to DE 1 119 711 (65f14) comprising a tilt sensor consisting of a pendulum, two hydraulic limit switches controlled when the ship is tilted to the left or right, a towbar lock actuator consisting of a cylinder and a piston rod, said two limit switches being connected in parallel and placed in series in the hydraulic control circuit of the actuator.

10 The towing hook is connected to the piston rod by an articulated bar. The articulation rod and piston rod rest on a semicircular plate. Each branch of the hydraulic line is connected at one end to the cylinder space in front of the piston and at the other end to the cylinder space 15 behind the piston.

When the vessel reaches a dangerous heeling angle to either the left or right side, the heeling sensor formed by the pendulum actuates the corresponding limit switch and opens the working fluid flow channel, allowing it to flow from the cylinder space in front of the piston 20 behind the piston. When a towing force is applied to the towing hook, the piston moves and opens the towing hook lock.

The second group includes a device in which the tow hook lock opens when the tow rope tension reaches a critical value of 25. The Wieckhoff system, manufactured in the Federal Republic of Germany, is already known. This system comprises a hydraulic non-return valve which operates automatically under the action of an overpressure valve when the pressure reaches a level corresponding to the critical tension of the tow rope.

30 In order to prevent the towing hook from opening when the force acts in the longitudinal plane of the vessel, the device is equipped with limit switches, one on each side of the vessel, which engage the automatic system only when the towing hook turns at a certain angle. The towing hook can then open under the influence of a certain critical force applied to it 35, regardless of the angle of the towing hook.

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The tow hook locks in the first group open based solely on the tilt angle, whatever the reason. Experience with such towing hook removal systems has shown that they only work satisfactorily in enclosed port areas, while towing hooks often open under the influence of the sea in situations where it is completely inappropriate. The automatic disconnection system must also be equipped with a blocking device that shuts off the system when moving to the high seas.

The second group of towing hook release systems does not take into account the effect of the ship's rocking and can open when the tow rope is subjected to tension caused by rocking on the opposite side of the rope, i.e. when there is no danger.

In addition, the tow hook locks associated with these devices can be opened by the effect of continuous traction regardless of the direction of action, i.e. regardless of the angle of the towing hook relative to the ship. This inevitably leads to the premature opening of the towing hook 20 in a certain corner area of the towing hook.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an automatic towing hook release device, the structure 25 and operation of which of the coupling circuit can guarantee the towing hook opening only in emergencies due to a combination of three factors: 1) The ship is at a critical heeling angle which could cause the deck to fill with water or stability.

(2) A towing force is subjected to a force whose horizontal component perpendicular to the longitudinal axis of the ship reaches a critical value equal to the force capable of tilting the ship to a critical angle.

35 3) The critical force acts on the same side as the ship is heeled.

77621 4

There is provided an automatic towing hook release device comprising a tilt sensor, two limit switches controlled alternately by the signals transmitted by the tilt sensor when the ship is heeling left or right and connected in parallel and placed in series in the towing hook lock actuator control circuit. equipped with a lever arm whose pivot axis is located in a longitudinal vertical plane in the center of the ship and fixed to the hull 10 of the ship, the lever arm is articulated to the towing hook and the two force sensors are arranged symmetrically with respect to the longitudinal vertical plane in the middle of the ship. the limit switch is each connected in series with one of the 15 main limit switches and each of them is controlled by signals transmitted by the respective force sensor.

The automatic towing hook release device according to the invention performs the automatic opening of the towing hook only when the ship is close to an emergency. This is achieved by monitoring the force acting perpendicular to the longitudinal vertical plane of the ship and the angle of heel of the ship. The device utilizes these parameters for selective operation, excluding the possibility of malfunction.

The device is designed to be suitable for different types of towing hooks and can therefore be installed on a ship during the construction phase or during renovation work.

The control circuit of the device can be either electric, hydraulic, pneumatic or electro-hydraulic depending on the structure of the towing hook, the conditions of the ship and the special requirements of the ship's crew.

The parts included in the towbar release are easily accessible at all yards. These types of equipment have long been widely used in shipbuilding and tested in practice. No new tools are needed.

- - 35 The device has proven to be very reliable because all its parts are located in the middle of the ship. The only component outside the 5,77621 Ia is a lever arm, which is a sturdy metal structure.

The need for maintenance of the device is minimal and the procedure for attaching the hook is very simple.

The invention will now be described in more detail by means of a specific embodiment thereof with reference to the accompanying drawings, in which:

Figure 1 shows a wiring diagram and a mechanical operation diagram of a ship's towing hook release device.

Figure 2 shows a vector diagram of the forces applied horizontally to the towing hook.

Figure 3 shows a vector diagram of the forces applied to the towing hook in a vertical plane perpendicular to the longitudinal vertical plane of the ship.

The automatic towing hook release device according to the invention comprises a tilt sensor 1 (Fig. 1) consisting of a pendulum suspended in a longitudinal vertical plane I in the middle of the ship, the extreme end of which is pressed by one limit switch 2 or 3 symmetrically with respect to said longitudinal plane I. The limit switches are connected in parallel and placed in series in the electric control circuit of the actuator of the lock 4 of the towing hook 5. In this embodiment, the actuator comprises a weight 6 supported in the tube 7 by a latch 8 fixed to the movable element of the electromagnet 9. The weight 6 is suspended by a string 10 passing through the rollers 11 and one end of which is fixed to the lock 4 of the towing hook 5. The stops 12 are arranged to limit the angle of oscillation of the pendulum sensor 1 with respect to the vertical plane I.

The device further comprises a two-arm lever 13, the pivot axis 14 of which is located in a longitudinal vertical plane I running in the middle of the ship and fixed to the ship's hull 15. One arm of the lever 13 is attached to the towing hook 5 by a joint 15, while the other end presses the lever 13 as it moves. a sensor 17 of a force sensor 17 arranged symmetrically with respect to the longitudinal vertical plane I of the ship. In this embodiment 6 77621, the force sensors 17 consist of pistons 18 loaded by springs 19 against a lever 13. The stops 20 are arranged to limit the angle at which the lever 13 can turn. The other ends of the pistons 18 may press either of the additional limit switches 5 or 22 connected in series with one of the limit switches 2 or 3.

The automatic towing hook release device according to the invention operates in the following manner.

The force T acting on the towing hook 5 (Fig. 1) can be divided into three components F, R and N, where F is directed upwards and determined by the ship's weight, R is parallel to the ship and determined by the ship's propeller thrust and 15 N is perpendicular to the longitudinal vertical plane of the ship I against and forms the force of tipping the ship, which is resisted by the restoring force of the ship.

From the point of view of ship safety, components F and R are irrelevant, while N components 20 should be monitored continuously.

Referring to Fig. 2, the lever 13 (Fig. 1) allows continuous monitoring of the component N of the horizontal force T, which is a function of the pivot angle of the towing hook 5 and the tension of the tow rope to the towing hook 5 by the force 25 T.

When the ship tilts to an angle fr (Fig. 3) and the towing hook 5 (Fig. 1) rises to an angle /}, the lever 13 still monitors the component N and takes into account the total angle / 3 + Θ. Fig. 3 shows that this is achieved by means of a lever 13 30 which transmits to the sensors 17 (Fig. 1) only that part of the force which is in a plane perpendicular to the longitudinal vertical plane I of the ship.

- · In this way, the lever 13 allows the sensors 13 to measure only the force T on the towing hook 5 component 35, which is a danger to the ship, as it is the most significant cause of the ship capsizing.

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The diagrams in Figures 2 and 3 also show several forces T at different angles Ä, / ¾ and Θ, all of which generate a critical Avon for the lateral component Hc.

Then the force T can vary between Hc ^ T i TQ, 5 where TQ is the breaking force of the tow rope.

The wiring diagram shows that the towing hook 5 (Fig. 1) can only open when either the contacts of the limit switches 2 and 21 close at the same time or when this happens at the limit switches 3 and 22. The limit switch 21 only closes 10 when the towing hook 5 turns to the starboard side and the lateral component N of the force T reaches a critical value Ν £, which can be guaranteed by the correct choice of the stiffness of the spring 19. The contact surfaces of the limit switch 2 meet only when the ship is critically tilted to the left. The same applies to the limit switches 15 with respect to the right side 22, and three of the ship.

When the limit switches 22 and 3 or 21 and 2 operate simultaneously, voltage is applied to the coil of the electromagnet 9 and the electromagnet 9 acts to pull the latch 8, which allows the weight 6 to fall into the tube 7. The weight 6 pulls the string 10 and opens the lock 20 4.

In conclusion, it can be reiterated that the device according to the invention guarantees the automatic opening of the towing hook only when the ship is close to the danger situation. This is certainly a significant advantage over prior art equipment and this alone, to the exclusion of many others, makes it unnecessary to build wider and deeper tugs or to resort to other measures to improve their stability to avoid capsizing.

30 An electrical embodiment has been described above, but the device may be based on pneumatically or hydraulically operated units.

However, the proposed electrical circuit is simpler, more reliable and less space consuming and is shown here as a preferred embodiment.

Claims (2)

8 77621 Industrial applicability The automatic towing hook release device according to the invention can be used in all tugs equipped with towing hooks. 5 An analysis of the statistical data on shipwrecks caused by water fillings or falls during towing or rescue operations shows that the proposed device could be advantageously used in tugs for rescue operations, maneuvering and towing with a short tow rope. . Claim lo An automatic towing hook release device comprising a tilt sensor and two limit switches controlled alternately by the signals 20 transmitted by the tilt sensor when the ship is heeled to the left or right and connected in parallel and placed in series with the towbar lock actuator control circuit, characterized by vip 13),: whose pivot axis (14) is located in a longitudinal vertical plane (I) 25 in the middle of the ship and is fixed to the hull (15) of the ship, and the arm of the lever (13) is articulated to the towing hook (5) and two force sensors (17) ) is arranged symmetrically with respect to the longitudinal vertical plane (I) of the vessel, the lever (13) pressing the sensors of the force sensors, and the other two limit switches (21, 22) are connected in series with one main limit switch (2,3) and each is controlled by the respective signals transmitted by the force sensor (17). il