WO2013095243A1

WO2013095243A1 - A ramp buttress and a ship ramp comprising such a ramp buttress

Info

Publication number: WO2013095243A1
Application number: PCT/SE2011/051586
Authority: WO
Inventors: Roger Simonsson
Original assignee: Cargotec Sweden Ab
Priority date: 2011-12-22
Filing date: 2011-12-22
Publication date: 2013-06-27

Abstract

A ramp buttress (1) for a ship ramp (2) is disclosed. The ship ramp (2) comprises a first (3) and a second (4) section, the first section (3) being hinged to a ship (5) at a first end (6) and the second section (4) being hinged to the first section (3) at a distance from said first end (6) of the first section (3). A buttress (1) is arranged between the first and second sections (3, 4), adjacent a second end (7) of the first section (3) and adjacent a middle part (8) of the second section (4) and on both sides of the ramp (2). The buttress (1) has a fixed length and is hinged at one of the sections and at least one buttress support (9) is arranged at the other section for keeping the buttress (1) in a predetermined position. The invention further relates to a ship ramp comprising such a ramp buttress.

Description

TITLE

A ramp buttress and a ship ramp comprising such a ramp buttress. FIELD OF THE INVENTION

The present invention relates to a ramp buttress for a ship ramp, the ship ramp comprising a first and a second section, the first section being hinged to a ship at a first end and the second section being hinged to the first section at a distance from said first end of the first section, wherein a buttress is arranged between the first and second sections, adjacent a second end of the first section and adjacent a middle part of the second section and on both sides of the ramp.

BACKGROUND

Wire-operated stern quarter ramps offer considerable advantages in cargo access. The main benefit is that it will allow the vessel to berth in the normal manner alongside a quay without the need for dedicated shore facilities. Long-haul car exports were originally handled by bulk carriers fitted with portable or hinge-away car platforms and loading/discharge performed by ship derricks or cranes. The massive rise in demand for global vehicle movements dictated purpose-designed multi-deck pure car carriers exploiting RoRo (roll on, roll off) cargo handling systems.

Ships with capacity for several thousands of vehicles on more than 10 decks emerged, along with pure car/truck carrier (PCTC) designs that offered rolling freight flexibility for a mix of vehicle types: not just cars but trucks, knockdown car units, containers and heavy project cargos. The success of this new breed and the growth of the trades they serve owe much to the efficiency of RoRo access/transfer installations in loading, stowing and discharging operations. A typical ship set embraces a stern quarter ramp/door, side ramp/doors mounted midships port and starboard, hoistable car decks, often served by mobile deck lifters (lorry-mounted scissor-lift platforms), internal ramps, ramp covers, and bulkhead doors. One difficulty encountered during all loading and unloading by means of trucks is that the ship rises and falls with the tide as the work proceeds, and in many places the tide water will have a deciding influence upon the position of the ship in relation to the quay. A ramp is usually hingedly connected to the ship in such a manner that the inner end of the ramp is level with a deck, and at sea the ramp is swung on board to a vertical position. Thus, the ramp structure is arranged to close the stern opening as a watertight door. In order to handle various sea levels the ramps are generally divided into at least two sections such that they can be bent relative one another. Hydraulic actuators or hydraulic cylinders are typically involved to adjust the angle. These have a hollow cylinder with a piston inserted in it. The two sides of the piston are alternately pressurized/de-pressurized to achieve controlled precise linear displacement of the piston and in turn the entity connected to the piston. The physical linear displacement is only along the axis of the piston/cylinder. This design is based on the principles of hydraulics. A familiar example of a manually operated hydraulic actuator is a hydraulic car jack. When the two sections are "parallel", i.e. the angle is 0° between the two sections, the actuators or cylinders do not hold any force. Thus, under ideal conditions the ramp can cope with very high weights, limited by the strength of the ramp itself. However, when the actuators are used to compensate for the ship deck not being at the optimum level versus the quay due to the tide (and sometimes the load), they can carry only as much as their dimensions allow them. The dimensions of these actuators can of course be dimensioned to carry heavy weights but at some point they themselves will constitute a too large a weight both literally and financially. A further disadvantage with these hydraulic actuators is that they sometimes have an oil leakage. The fines for oil spillage in harbours are significant, not to mention the environmental aspect of it.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a ramp system which alleviates some of the problems mentioned above.

This object is achieved by the ramp buttress and ramp as set forth in the appended claims.

A ramp buttress for a ship ramp is provided. The ship ramp comprises a first and a second section, wherein the first section is hinged to a ship at a first end and the second section is hinged to the first section at a distance from said first end of the first section. A buttress is arranged between the first and second sections, adjacent a second end of the first section and adjacent a middle part of the second section and on both sides of the ramp. The buttress has a fixed length and is hinged at one of the sections and at least one buttress support is arranged at the other section for keeping the buttress in a predetermined position.

In some situations ships wanting to unload heavy items with prior art solutions will have to wait for the proper water level. By replacing an actuator/cylinder with a movable "stanchion", the ramp can take a much higher load independently of the relative position of the first section versus the second section.

Preferably the buttress comprises an arrangement for moving the buttress about its hinge and between at least two positions. This could for instance be some kind of handle grip More preferred is to have an actuator with a rod for moving the buttress. The moving of the buttress could then be automated.

According to one aspect of the present invention the actuator is a hydraulic actuator. More preferred is to have an electric actuator and thereby avoiding the risk of oil leakage. An electric linear actuator is a device that converts the rotational motion of an electric motor into linear motion, i.e. push and pull movements. This way it is possible to lift, adjust, tilt, push or pull heavy or hard-to-reach objects simply by pushing a button.

Additionally, these actuators provide a safe, quiet and clean movement with accurate motion control. They are energy efficient and have a long lifetime with little or no maintenance. Installing such an actuator is very easy compared to e.g. hydraulic systems and it takes up much less space, as it has no pumps or hoses.

The coupling of electronic and hydraulic technology is becoming increasingly common, especially in electro-hydraulic actuators. Advances in transducer logic and control capabilities have resulted in cylinders that transmit high forces with a high degree of positioning accuracy. Key to the operation of these actuators is the feedback system. A number of different feedback systems, both mechanical and electrical, are used, depending on the accuracy and durability required. An electro-hydraulic actuator is generally a self-contained, bi-directional DC motor driven pump with an integral hydraulic cylinder.

One method for accurately sensing cylinder rod position is with a linear displacement transducer. In one widely used system, the transducer housing is mounted to the cylinder end cap, with the sensor rod extending into the hollowed-out piston rod. There is no physical contact between the sensor and cylinder rods. To determine position, a magnet is attached to the cylinder piston. Current pulses transmitted down the sensor interact with the magnetic field and return a sonic pulse. Distance can be determined by measuring the transmission/reception time interval. High positioning accuracy is possible, much higher than what is needed for the purposes of the present invention.

Thus, according to another aspect of the present invention the actuator is an electro-hydraulic actuator. According to a further aspect of the present invention the free end of the buttress has a concave shape and the buttress support is a pin. With this sort of plug and socket solution the exact position of the buttress relative the buttress support is not necessary. The concave shape is "forgiving" since the buttress will be guided towards the correct position if the support and buttress would be slightly misaligned when moved towards one another. An alternative is of course that instead the free end of the buttress has a convex shape and the buttress support has a corresponding notch. Further, the shape of the "concave" part could alternatively be triangular or any other shape as long as the deepest part is centred.

Preferably, the buttress is made from steel which has a high strength, in fact, as building material steel has the highest strength to weight ratio. The production methods have been made speedier and thriftier. Further advantages of steel are therefore that it is easy to obtain and relatively cheap.

According to yet another aspect of the present invention there are at least two buttress supports for providing at least two working angles between the first and second sections.

According to a further aspect of the present invention a ramp for a ship is provided comprising a first section, a second section, and a ramp buttress. According to one aspect of the ramp of the present invention the buttress is arranged on the first section and the buttress support is arranged on the second section. Preferably, the ramp comprises a third section and this third section is preferably a flap.

According to yet another aspect of the present invention a position sensor connected to a control unit is arranged adjacent the buttress for correct positioning of the buttress. BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be further disclosed with reference to the accompanying drawings.

Figure 1 is a partial side view of a ship showing a ramp on the stern of the ship in raised position.

Figure 2 is a partial side view of a ship showing a ramp on the stern of the ship in loading position. Figure 3 is a side view of the first and second sections of a ramp with a buttress holding the sections in an angle relative one another according to the present invention.

Figure 4 is a side view of the first and second sections of a ramp, the sections not angled relative one another.

DISCLOSURE OF PREFERRED EMBODIMENTS

Figure 1 shows a part of a ship 5 with a ramp 2 in a raised position. The ramp 2 is raised and lowered with the help of wires 14 which also could hold the ramp 2 in place in the raised position but a separate locking mechanism is preferred. Another locking mechanism is used to lock the second section 4 in the raised position. When the ramp 2 is being lowered the locking mechanism of a second set of wires 15 is first disengaged and when the line of wires 15 between the connecting point 16 on the first section 3 and the connecting point 17 on the second section is above the hinging point 18 the wires 15 will pull in order lift the second section 4.

In figure 2 the ramp 2 is shown in the loading position, i.e. the lowered position. Figures 3 and 4 show a buttress 1 for a ship ramp 2 in more detail. The ship ramp comprises a first 3 and a second 4 section. The first section 3 is hinged to a ship 5, see figures 1 and 2, at a first end 6 and the second section 4 is hinged to the first section 3 at a distance from said first end 6 of the first section 3. A buttress 1 is arranged between the first and second sections 3, 4, adjacent a second end 7 of the first section 3 and adjacent a middle part 8 of the second section 4 and on both sides of the ramp 2. The buttress 1 has a fixed length and is hinged on the first section 3. In the shown embodiment three buttress supports 9 are arranged on the second section 4. Thus, apart from the "unloaded" position shown in figure 3, there are three possible angles or three predetermined positions for the buttress 1 .

The buttress 1 comprises an arrangement 10 for moving the buttress 1 about its hinge and between 4 different positions. As further can be seen the arrangement for moving the buttress 1 is an actuator 10 with a rod 1 1. In the shown embodiment the actuator could be electric, electro-hydraulic or hydraulic.

As further can be seen in figures 3 and 4 the free end 12 of the buttress 1 has a concave shape and the buttress supports 9 are pins. As an alternative (not shown) the free end of the buttress could instead have a convex shape and the buttress support has a corresponding notch. The contact portions of the buttresses and buttress supports could of course have any shape as long as the buttresses are locked laterally in working position.

In figure 3 the buttress 1 is not holding any load, the first and the second sections 3, 4 simply rest against each other at a contact point 19. Starting from the relative position of the sections 3, 4 in figure 3 and changing to the position in figure 4, the wires 14 will first lift the first section 3 more than desired. The reason for this is to allow for the buttress 1 to be moved (to the left in the figures) to a position just over a buttress support 9. When this position is reached the first section 3 is lowered until the buttress 1 and buttress support 9 are in locking engagement.

An alternative is to first check the ship's level in relation to the quay and immediately arrange the two sections in the best possible angle upon the initial lowering of the ramp when the ship has made port. This could be automated by using for instance a distance sensor connected to a control unit controlling the lowering of the ramp.

Returning to figures 1 and 2 the ramp 2 comprises a third section 13 which in the shown embodiment is a flap. The flap 13 is used in this case to provide a smooth transition from the ramp to the quay 20, see figure 2.

The foregoing is a disclosure of an example practicing the present invention. However, it is apparent that method incorporating modifications and variations will be obvious to one skilled in the art. Inasmuch as the foregoing disclosure is intended to enable one skilled in the art to practice the instant invention, it should not be construed to be limited thereby, but should be construed to include such modifications and variations as fall within the scope of the claims. For instance, instead of having a pin acting as buttress support it could be a bar arranged between two wall structures and thus limiting the lateral side movement of the buttress. Further, the embodiment shown in the figures has three buttress supports. However, it is of course possible to vary this as desired with everything from one buttress support up to as many as wanted as long as they fit on the ramp. Also, the distance, or rather the size of the steps between the buttress supports, could be varied, i.e. the resolution.

Claims

1 . A ramp buttress (1 ) for a ship ramp (2), the ship ramp comprising a first (3) and a second (4) section, the first section (3) being hinged to a ship (5) at a first end (6) and the second section (4) being hinged to the first section (3) at a distance from said first end (6) of the first section (3), wherein a buttress (1 ) is arranged between the first and second sections (3, 4), adjacent a second end (7) of the first section (3) and adjacent a middle part (8) of the second section (4) and on both sides of the ramp (2),

c h a r a c t e r i s e d i n

that the buttress (1 ) has a fixed length and is hinged at one of the sections and that at least one buttress support (9) is arranged at the other section for keeping the buttress (1 ) in a predetermined position.

2. A ramp buttress (1 ) according to claiml , wherein the buttress (1 )

comprises an arrangement (10) for moving the buttress (1 ) about its hinge and between at least two positions.

3. A ramp buttress (1 ) according to claim 2, wherein the arrangement for moving the buttress (1 ) is an actuator (10) with a rod (1 1 ).

4. A ramp buttress (1 ) according to claim 3, wherein the actuator (10) is a hydraulic actuator.

5. A ramp buttress (1 ) according to claim 3, wherein the actuator (10) is an electric actuator.

6. A ramp buttress (1 ) according to claim 3, wherein the actuator (10) is an electro-hydraulic actuator.

7. A ramp buttress (1 ) according to any of the previous claims, wherein the free end (12) of the buttress has a concave shape and the buttress support (9) is a pin.

8. A ramp buttress (1 ) according to any of the claims 1 to 6, wherein the free end (12) of the buttress has a convex shape and the buttress support has a corresponding notch.

9. A ramp buttress (1 ) according to any of the previous claims, wherein the buttress (1 ) is made from steel.

10. A ramp buttress (1 ) according to any of the previous claims, wherein there are at least two buttress supports (9) for providing at least two working angles between the first and second sections (3, 4).

1 1 . A ramp (2) for a ship (5) comprises a first section (3), a second section (4), and a ramp buttress (1 ) according to any of the previous claims.

12. A ramp (2) according to claim 1 1 , wherein the buttress (1 ) is arranged on the first section (3) and the buttress support (9) is arranged on the second section (4).

13. A ramp (2) according to any of the claims 1 1 and 12, wherein the ramp (2) comprises a third section (13).

14. A ramp (2) according to claim 13, wherein the third section (13) is a flap.

15. A ramp (2) according to any of the claims 1 1 to 14, wherein a position sensor connected to a control unit is arranged adjacent the buttress (1 ) for correct positioning of the buttress (1 ).