CA2518301C - Fender structure - Google Patents

Abstract

A description is provided of a soft and energy-absorptive fender (10) where the essential feature is that it is a body formed of a series of hollow chambers (12) which are designed to be full of, or filled with, a fluid, where the chambers are separate from one another and linked via connecting areas (14) between the chambers and where each chamber (12) has a fluid connection with the adjoining chamber(s). A description of the application of the device is also provided.

Description

Amended page 1 FENDER STRUCTURE

The invention relates to fender structures. The preferred applications for the fender structures according to the invention are also described.
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-absorbing 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-absorbing effect. Marinas are designed and constructed in many different ways and there is a great need for a soft, energy-absorbing, easy-to-mount fender system which is suitable for mounting to the various types of facilities.
The use of soft, energy-absorbing fender systems is well-known, and in this regard, reference is made to US patent 3,305,259 which discloses a shock-absorbing fender containing a continuous gas-containing elastic tube, which is divided into compartments hermetically sealed from each other. However, as the individual compartments are mutually hermetically sealed, the structure is unable to provide shock-absorbing properties as intended with the present structure. As the compartments are filled with air during extrusion of the tube, there is not further possibility of air pressure adjustment after the tube/fender has been produced. Further, there is no kind of "throttle valve" functions, and in applications where "on-force"
deformations can take place, this might easily lead to puncturing of the compartments.
A further disadvantage is the difficulty to obtain a sufficient air pressure inside each compartment. The physical explanation for this is that the extruded tube (rubber or thermoplastic) is in a very soft "melt phase" (around 200 C) as it is filled with air. The inside air pressure in the tube must be rather low to avoid that the melt expands unintentionally. As the hot air inside the tube/compartments cools off, the air pressure Amended page 2 will be correspondingly reduced. Obviously the forming of the soft extruded melt has to take place in apressure-chamber" to be able to reach an air pressure inside the tube that is higher than the atmospheric pressure after cooling down the tube to ambient temperature.
Further, the prior art fender-system can not be deflated and transported in compact rolls, and shipment as well as storage (by local dealers) will be more expensive. The practical use of the prior art solution is rather limited compared with the fender of the present invention.
The structure of the present invention does not face the above mentioned problems as the air pressure in the compartments can be adjusted within close tolerances at any time after production The most commonly used soft and energy-absorbing fender systems however are formed as individual, hollow bodies filled with air or plastic foam, and their geometric design varies 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 fender structure according to the invention is characterized in that each chamber has a fluid connection with the adjoining chamber or chambers.
According to the invention the device is used to provide energy-absorbing 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. The fender system according to the invention is also well-suited for use on tug boats, supply vessels, rescue vessels and similar.

Amended page 3 The present invention describes a product in the form of a fender which is particularly energy-absorbing and suitable for a variety of shock absorbing applications 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 energy-absorbing 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 comers 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 Amended page 4 and flexible materials in cold as well as warm 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. 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-absorbing properties, proof against puncturing and mechanical strength.
The solution according to the invention can furthermore be dimensioned within a variety of parameters to achieve the desired energy-absorbing 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.

Amended page 5 The energy-absorbing 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 fastening, 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 joints, 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 crosslinking compound of plastic or similar which is cross-linked after tilling.
To achieve an energy-absorbing 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 (stocking) 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 Amended page 6 into the chamber through the holes in the outer stocking. This provides a solution in which air can be filled into the chambers but cannot get out again, as a result of the mentioned stocking.
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 will be determined 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 designing the duct-valve system according to the desired energy-absorbing effect, by having the duct's outlets in the chambers function as throttle valves when the filling medium (air) flows between the individual chambers, or as check valves when the filling medium is not allowed to flow out of the chambers but only in the 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.

Amended page 7 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 7C.
FIGURE 4 shows a detailed drawing of two chambers with a compact area between the two as in Figure 2, but where the tender 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 stocking is run through the fender.
FIGURE 7A shows a side view of the fender system as a preferred embodiment would actually appear.
FIGURE 7B shows a plane section of the fender system according to Figure 7A.
FIGURE 7C shows the cross section and the end view of D-D in Figure 7B.
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), PVC, 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 different 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 tilled with a fluid, such as air or a liquid. A suitable thickness for the wall of the hollow profile would normally 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.
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 tube 18 which runs through each chamber 12, a through-going hole 20 is formed in the tube wall. Here, the tube 18 can be Amended page 8 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. 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 fastening strips, screws/nails, and the like to fix the fender to the base.
The lineltube 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 .
The chambers 12, the 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 line/tube with an outer stocking is run through the fender. The inner lineltube is shown at 18, while the stocking, which is of a dense, elastic material, is shown at 22. Both these two (line 18 and stocking 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 stocking 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 stocking 22 will be lifted out from the surface of the tube, and the air will flow into the space between the tube/stocking up to the hole 24 and then out into the chamber 12. When the pumping stops, and the pressure in the chamber 12 is higher than Amended page 9 in the line 18, it will cause the stocking 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 (Figure 7C). At the other end the tube can be connected to a source of compressed air in order to till the chambers. An ordinary car tire 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. The line's dimensions, the dimensions of each hole in the line, determine the transmission of the fluid and corresponding pressure build-up through the row of chambers. In this way the fender's capacity for absorbing impact energy can be determined to fit a large variety of applications. 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 side of the end-view drawing. The fender has thus acquired more of an oval section as is evident in Figure 7C. The compressed central parts 14 thus form a foot 30 which can be used to fix the fender to the base. 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 have contact face to the mentioned base.
The principle on which the fender system is based is the same, irrespective of what the tender'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 Amended page 10 ducts providing a soft dampening and energy-absorptive effect to each chamber being a closed container after filling (Figure 6).
The possibility is also provided for that the duct is not in the form of a through-running tube, but are isolated "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.

Claims (18)

1. A fender structure comprising a body which forms a series of hollow chambers which are separate from one another and mutually linked by means of connecting areas between each chamber, and each chamber is arranged to be filled with a fluid, characterized in that each chamber has a fluid connection with the adjoining chamber or chambers, wherein the fluid connection is established by means of a continuous fluid-conducting line which runs through the chambers and the connecting areas, and the line includes at least one hole for each hollow chamber through which it runs, and each hole of the line in the chambers function as throttle valves when the fluid flows between the individual chambers.

2. The fender structure according to claim 1, characterized in that the line is embedded in the material in the connecting areas.

3. The fender structure according to claim 1, characterized in that the fluid connection is established with the aid of a duct, or a bore channel, which runs through the connecting areas.

4. The fender structure according to any one of claims 1-3, characterized in that the line is partially connected to an inner wall of the chambers, or it runs free with the inner walls of the chambers.

5. The fender structure according to any one of claims 1-4, characterized in that a capacity of the fender structure to absorb energy is determined by the dimensions of the line and the dimensions of each hole in the line, thus influencing a transmission of fluid through a row of chambers when one or more of the chambers is/are compressed.

6. The fender structure according to any one of claims 1-5, characterized in that the fluid is a gas or a low viscosity curable compound of plastic which is cross-linked after filling.

7. The fender structure according to any one of claims 1-6, characterized in that the connecting areas are flat, compact areas used to fix a fender chain to a base with the use of fastening strips or rope, or by inserting nails or screws through the area and into the base.

8. The fender structure according to any one of claims 1-7, characterized in that the fender structure is produced from an elastic material.

9. The fender structure according to any one of claims 1-8, characterized in that the line is arranged to be plugged at one end, and at the other end to be connected to a source of compressed air in order to inflate the chambers.

10. A fender structure comprising a body which forms a series of hollow chambers which are separate from one another and mutually linked by means of connecting areas between each chamber, and each chamber is arranged to be filled with a fluid, characterized in that each chamber includes a fluid connection with the adjoining chamber or chambers by means of a continuous fluid-conducting tube which runs through the chambers and the connecting areas, and the tube includes at least one outlet/hole for each hollow chamber through which it runs, and the tube is designed with a check valve which prevents the fluid out of the chamber again once it has first entered.

11. The fender structure according to claim 10, characterized in that said check valve being provided by the fluid carrying tube being enclosed by an elastic sheath-formed tube, and the sheath-formed tube are equipped with at least one hole, in each chamber through which the tube runs, in that said holes in the tube and the holes in the sheath-formed tube are axially displaced in relation to one another in a non-overlapping configuration.

12. The fender structure according to any one of claims 10-11, characterized in that a stocking is embedded in or cast into a material in the connecting areas and is partially connected to an inner wall of the chambers, or it runs free with the inner wall of the chambers.

13. The fender structure according to any one of claims 10-12, characterized in that the fluid is a gas, a liquid, or a low-viscosity curable compound of plastic which is cured/cross-linked after filling.

14 The fender structure according to any one of claims 10-13, characterized in that the connecting areas are flat, compact areas used to fix a fender chain to a base with the use of fastening strips or rope, or by inserting nails or screws through the area and into the base.

15. The fender structure according to any one of claims 10-14, characterized in that the fender structure is produced from an elastic material.

16. The fender structure according to any one of claims 10-15, characterized in that the tube is arranged to be plugged at one end, and at the other end to be connected to a source of compressed air in order to inflate the chambers.

17. The fender structure according to any one of claims 1-16, characterized in that the body is coiled into at least one roll, and configured so as to be cut at a predetermined length and filled from at least one filling valve.

18. Use of a fender structure comprising a fender having a body which forms a series of hollow chambers which are separate from one another and mutually linked by means of connecting areas between each chamber, and each chamber is arranged to be filled with a fluid, characterized in that each chamber has a fluid connection with the adjoining chamber or chambers established by means of a line which runs through the chambers and the connecting areas, and the line includes at least one hole for each hollow chamber through which it runs, and each hole of the line in the chambers function as throttle valves when the fluid flows between the individual chambers, wherein the use is for the energy-absorbing protection of objects which are exposed to dynamic stresses, and which come into contact with one another, or which are moored at jetties, in pontoon enclosures or on shore, or to protect, support and stay general cargo in transit.