Fender systems are used for the energy-absorptive protection of objects, such as motor vehicles and other materiel, which are exposed to dynamic stresses.

A typical application for fenders is the protection of boats which come into contact with one another or which are moored at jetties, in pontoon enclosures or to shore.

Another related area of application is, for example, to protect, support and stay general cargo in transit, such as in cargo holds in ships, in containers or on lorries.

The fleet of pleasure boats and corresponding jetty installations are growing at a great rate and represent considerable assets. Each year insufficiently soft, energy- absorptive fendering of boats and jetties leads to considerable damage to boat hulls.

If jetties and pontoon enclosures include fenders they are usually in the form of plastic profile extrusions etc. which do not have the desired softness and energy- absorptive effect. Marinas are designed and constructed in many different ways and there is a great need for a soft, energy-absorptive, easy-to-mount fender system which is suitable for mounting to the various types of facility.

The use of soft, energy-absorptive fender systems is well-known, which primary feature is that they are formed as individual, hollow bodies filled with air or plastic foam, and their geometric design variy between a cylindrical form and a spherical form of limited length per unit. Such traditional fenders are hung along the

side of the vessel and/or on the jetty with rope, fixing brackets or similar. However, fenders of the individual buoy type provide no uniform, flexible solution for the many different types of craft which a marina is intended to serve.

For further information about the status of the technology with regard to fenders, please refer to the many boating magazines which are available, such as the magazine"Batmagasinet"and catalogue material such as"Maritime".

An object of the invention is to produce a new fender system which overcomes all the above-mentioned disadvantages.

A further object of the invention is to produce a fender system which is of simple construction, which is simple to mount, and which is reliable.

The device of a fender system according to the invention is characterized in that it consists of a body forming a series of hollow chambers which are designed to be full of, or filled with, a fluid, where the chambers are mutually separate from one another and linked via connecting areas between each chamber, and where each chamber has a fluid connection with the adjoining chamber (s).

The especially preferred embodiments of the fender system according to the invention are described in the independent patent claims.

According to the invention the device is used to provide energy-absorptive protection of objects such as motor vehicles and other materiel which are exposed to dynamic stresses, such as vessels (pleasure craft) which come into contact with one another, or are moored at jetties, in pontoon enclosures or to shore, and/or to protect, support and stay general cargo in transit, such as in cargo hold of vessels, in containers or on lorries, according to claim 16. The fender system according to the invention is also well-suited for use on tug boats, supply vessels, rescue vessels and similar.

The present invention describes a product in the form of a fender which is particularly soft and energy-absorptive while at the same time being easy to mount on jetties and marina facilities. If a single chamber in the fender system is compressed, the air in the chamber is simultaneously forced out through the openings/holes in the connecting areas between the chambers and into the adjoining air chambers on each side. The flow resistance which arises when the air is forced out gives the mentioned dampening effect. When a through-running flexible tube is used between the chambers, where the tube includes one or more outlet holes in the

tube wall, the air must first be forced into the tube through the holes and then be forced onward through the tube to the adjoining chambers.

According to the invention, the fender is in the form of an"infinitely long"chain of linked, soft, energy-absorptive (air-filled) elements, and for delivery to market may be coiled on a roll or drum. The fender can be cut to the desired length to fit the place where it is to be mounted and the entire length can be filled with air from only one filling valve, which can be devised in an easily accessible place (with the duct/tube at each end of the fender then being plugged/sealed). The fender can be bent around corners and edges, and can be largely made to fit the contours of the base in question.

The fender can be fixed to a large number of different constructions which require shock-absorbent protection, i. e. constructions above and/or below water and in all desired directions.

According to the invention, the area where the fender system can be fixed to the base is recessed and thus protected against rubbing and/or contact.

The fender according to the invention may be produced from a number of elastic materials, including thermoplastic polyurethane (TPU), which is one of the most durable and flexible materials in cold conditions that is currently available. The material commonly used today in rubbing strakes and fenders is soft PVC, which in the context mentioned here does not have the same excellent mechanical properties as the preferred material TPU.

All thermoplastic materials, as well as rubber materials and cross-linked materials, can be used.

The fender solution may easily be glued and/or welded, thus permitting any damage to be repaired, and it can also be cut and spliced with splicing pieces which are pressed or glued into the inner tube.

The solution provides a particularly good energy-absorptive effect because, being filled with a gas or liquid, it functions as a dynamic unit in which the chambers work together with the help of a specially designed, built-in"pressure control system".

This"pressure control system"functions as individual throttle valves or check valves for each chamber, where the throttle can be adjusted depending on the design of the valve system, in all variants ranging between soft dampening, where the ducts are open particularly wide, and a tight seal if the tube is designed with a check valve which does not let the air out of the chamber again once it has first entered.

In applications where the fender is exposed to particularly high stresses, the fender system can be filled with a liquid which subsequently hardens to form a solid, energy-absorptive mass, including foam also. Such a liquid can, for example, be two- component or multi-component polyurethane.

Through a choice of alternative filling materials and valve systems, the fender system can be adapted to satisfy various requirements with regard to energy- absorptive properties, proof against puncturing and mechanical strength.

The solution according to the invention can furthermore be dimensioned within wide parameters to achieve the desired energy-absorptive effect. In the case of small jetties and pontoon enclosures, as well as vertical-walled quay structures, the fender according to the invention can be mounted as desired, either vertically, horizontally or crosswise, etc.

The energy-absorptive fender's design permits it to be used as a fender around a boat hull. The bow and gunnels of a boat are particularly vulnerable to wear and tear and this fender design can provide better protection for such areas.

A soft fender is achieved by producing energy-absorptive chambers. In order to make the fender easy to mount, the chambers are produced with a flat, compact area between each chamber, enabling the fender chain to be fixed to a base in a number of different ways, such as for example using strips, nails, screws, rope, brackets etc.

When mounting, the fixing points will, as mentioned in a previous paragraph, be recessed so as to prevent the hull from coming into contact with screw heads and similar or from rubbing and destroying strips, rope or other fixing means.

To make the chambers energy-absorptive, the volume, filling medium and pressure must be adjusted to the specific amounts of impact energy which may arise in the (jetty) facility in question. In order to achieve a combination of soft and controlled energy-absorptive effects, the different chambers are connected to one another so that the flat, compact areas and the chambers between these areas enclose a tube-formed check valve or throttle valve which connects all hollow spaces, dimensioned and shaped in accordance with the desired dampening and/or checking effect.

To achieve high strength and to avoid unwanted air leakage, the soft, energy- absorptive fender can be produced in a single homogenous piece of material without

joins, glue joints or similar, where the compact and flat areas, the valve system and the hollow spaces are permanently connected with one another.

According to a preferred embodiment of the invention, the fluid with which the chambers are filled is a gas such as air, a liquid such as oil or water, or a low- viscosity temperable compound of plastic or similar which is cross-linked to foam formation when it hardens after filling.

To achieve a soft, energy-absorptive fender with particularly high stiffness, the connection between the different hollow spaces can be blocked when excess pressure arises in the chambers by enclosing the inner duct/line with an elastic tube, and equipping both the duct and the tight-fitting elastic tube sheath with at least one radial hole in each chamber through which the valve system runs, and these holes are displaced axially in relation to one another so that they do not overlap. This will allow air with excess pressure to leak from the tube and into the space between the two tubes, and be let out into the chamber through the holes in the outer sock. This provides a solution in which air can be filled into the chambers but cannot get out again, as a result of the mentioned sock.

The connecting duct or the tube-formed throttle valve and/or check valve is enclosed by, and permanently connected to, the surrounding material in the (flat) compact area between the hollow spaces. In the intermediate energy-absorptive chambers, the connecting tube is only partly permanently connected to the surrounding material (the wall), i. e. it can be joined or attached to the inner wall of each chamber. Alternatively, it can run completely free and without contact with any of the inner walls which define the chamber.

To avoid air leaking from one chamber into another apart from through the duct/opening through the central part, the design ensures a tight seal between the chambers as the enclosing, tight-fitting tube sheath is permanently fixed to, and forms a homogenous material with, the compact (flat) areas between the hollow spaces.

The embodiment of the fender system functions as intended as a result of the combined effect of the constructive design and the technical flow conditions. The dynamic effect is achieved by adjusting the size of the fender's chambers, the pressure of the filling medium, and the connecting duct's diameter and outlet cross section in each chamber, where the flat, compact areas and the hollow spaces

between these areas enclose and are permanently connected to a"duct-valve system"for transport of fluid/filling medium between the chambers.

The dynamic effect is achieved by adjusting the duct-valve system to the desired energy-absorptive effect, by having the duct's outlets in the chambers function as throttle valves or check valves when the filling medium (air) flows between the individual chambers.

A detailed description of the invention will now be provided with reference to the accompanying drawings, in which: FIGURE 1 shows a longitudinal drawing of the fender system according to the invention.

FIGURE 2 shows a detailed drawing of two chambers with a compact (connecting) area between the two, i. e. from the same side as the longitudinal drawing in Figure 1.

FIGURE 3 shows a cross section, and partly in the form of a perspective, of the fender taken along the line A-A in Figure 2. The cross sections can have different geometric shapes and another preferred example is shown in Figure 7.

FIGURE 4 shows a detailed drawing of two chambers with a compact area between the two as in Figure 2, but where the fender is turned 90°.

FIGURE 5 shows a section of Figure 4, with a continuous line/tube running through the fender, and where one or more holes in the wall of the line/tube form a fluid connection between the inside of the line and the chambers.

FIGURE 6 shows a drawing analogous to Figure 5, where a line/tube with an outer sock is run through the fender.

FIGURE 7A shows a side view of the fender system as it would actually appear.

Figure 7B shows a plane section of the fender system according to Figure 7A.

Figure 7C shows a drawing of the end viewed from the left of the fender system according to the invention.

The description will refer firstly to Figure 1, which shows parts of a continuous fender construction according to the invention.

The fender 10 is formed from a number of hollow, bag-shaped chambers 12 which are defined by an elastic material, such as thermoplastic polyurethane (TPU), PVS, rubber or similar. The fender can be manufactured from a long hollow profile with the desired cross section form, which at regular intervals is compressed flat to

form the solid, compact between-lying connecting areas 14. The hollow profile, which can have differing geometric cross sections, appears in the present example with a mostly circular cross section. Figure 7 shows a preferred example of the profile.

Between two connecting areas 14 the hollow profile forms a chamber 12 which can be filled with a fluid, such as air or a liquid. The most suitable thickness for the wall of the hollow profile would be in the region of 3-5 mm. With the help of compressed air the chambers can be"inflated", and the fender/through-going line can be sealed at each end.

An enlarged section is shown in Figure 2. A hollow line or tube 18 runs through the inside of each chamber 12 and is embedded in the solid connecting area 14. In the parts of the tube 18 which run through each chamber 12, a through-going hole 20 is formed in the tube wall. Here, the tube 18 can be partially connected to the inner wall of the chamber 12 or run free, i. e. so that it has no contact with the inner walls of the chamber.

Figure 3 shows a cross section, and partly in the form of a drawing, of the fender 10 taken along the line A-A in Figure 2. The chamber-forming body 12 is made, together with the compressed central part 14, of solid plastic material. Figure 7 shows a corresponding section where the chamber-forming body 12 has a different geometric shape. In this embodiment, the wall and the compressed central parts 14 form a foot which can be used to fix the fender to the base with, and to which it must be fixed. The fender is then laid with the foot side down against the base and can then be fixed to the base. As shown in Figure 7B, the central part 14 includes holes 34 for inserting screws/nails to fix the fender to the base.

The line/tube can be replaced by creating a duct or boring a channel through the solid material of the central part 14 between the chambers, alternatively in the form of a through-going embedded bit of tube, so that a fluid connection is established between two adjoining chambers 12.

Figure 4 shows a drawing analogous to Figure 2, but where the fender is turned 90°. Both the chambers 12, the central part 14 and the tube 18 are shown.

Figure 5 shows in greater detail how the tube 18 runs through the chamber 12, and the figure indicates the hole 20 in the tube wall.

Figure 6 shows a drawing analogous to Figure 5, where a lineltube with an outer sock is run through the fender. The inner line/tube is shown at 18, while the sock, which is of a dense, elastic material, is shown at 22. Both these two, line 18

and sock 22, include a hole going through their respective walls. This is shown at 24 and 20. While the inner line 18 can be of a relatively stiff but flexible plastic, the outer sock 22 is elastic.

When filling the chambers with a fluid, such as air, this double tube system 18, 22 will function as follows : Compressed air is pumped into the tube 18. At a given excess pressure the outer elastic sock 22 will be lifted out from the surface of the tube, and the air will flow into the space between the tube/sock up to the hole 22 and then out into the chamber 12. When the pumping stops, and the pressure in the chamber 12 is higher than in the line 18, it will cause the sock to"cling"tight to the line 18, and stop the air returning the same way as it came in.

The inner tube thus runs through the entire length of the fender 10, and can be plugged at one end at 32. At the other end the tube can be connected to a source of compressed air in order to fill the chambers. An ordinary car tyre valve mounted in the duct can be used to plug the end, as indicated at 32.

With this fender system according to the invention, with the exception of the embodiment according to Figure 6, the pressure (i. e. the air) will be transmitted through the entire length of the fender (via the line 18) when one or any chamber is compressed. By adjusting the line's dimensions, the dimensions of each hole in the line, it is possible to adjust this transmission of pressure through the row of chambers. In this way the fender's capacity for absorbing impact energy can be regulated. The embodiment of the invention in Figure 6 shows an embodiment in which maximum stiffness is achieved, since the air cannot flow back.

Figures 7A, 7B and 7C show a side view, a plane view and an end view respectively of the most preferred embodiments of the fender system according to the invention. In this solution the chamber-forming body 12 has a different geometric shape. Compared with the side-view drawing in Figure 3, the compressed central parts 14 are displaced from the central position and towards one end of the end-view drawing. The fender has thus acquired more of an oval section as is evident in Figure 7C. The wall and the compressed central parts 14 thus form a foot 30 which can be used to fix the fender to the base with, when it is to be fixed to the base (the beam etc. ). This is the most preferred embodiment of the invention because the solid central parts 14, through which fixing media such as nails, screws and similar can be inserted to fix the fender to the base, will then lie right up to the mentioned base.

The principle on which the fender system is based is the same, irrespective of what the fender's chambers are filled with. A common inside filling valve is used (32 in Figure 7), where a number of connected chambers can be filled in one operation, and where the fender's total dampening characteristics can be"tuned"by selecting the type and dimensioning of the valve system and selecting the filling medium.

Variants of the valve's design will determine to what extent the filling medium is permitted to flow between the respective chambers, adapted in all degrees from open ducts providing good dampening and energy-absorptive effect to each chamber being a closed container after filling (Figure 6).

The possibility is also provided for the duct not to be in the form of a through- running tube, but for it also to be isolated to"valve segments"placed in the flat hollow spaces. A common feature of this solution is that the valve tube and fender form an integral unit in the flat, compact areas irrespective of which type of valve system is used.