US3695046A

US3695046A - Fenders

Info

Publication number: US3695046A
Application number: US5430A
Authority: US
Inventors: Ralph P Torr; Juncker Zelo Nicolaisen
Original assignee: Andre Rubber Co Ltd
Current assignee: Andre Rubber Co Ltd
Priority date: 1969-01-23
Filing date: 1970-01-23
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03
Also published as: FR2028958A1; NL7000657A; NL165804C; NL165804B; DE2003031A1; GB1295051A; DE2003031B2; DE2003031C3; SE372581B; JPS4916910B1; FR2028958B1

Abstract

A fender arrangement for a jetty, dockside, dolphin or the like comprising a fender mounted for load-absorbing movement towards the edge of the jetty against the action of normally unstrained elastomeric tension springs in the form of endless bands looped between mounting pedestals carried by the jetty and the fender. The fender may be slender driven piling or bodily carried and guided by the jetty. Tension springs of elastomeric material show specified advantages over compression and shear springs in jetty fenders.

Description

United States Patent [151 3,695,046

Torr et al. 1 Oct. 3, 1972 [54] FENDERS 1,191,445 7/1916 Lowy ..114/219X [72] Inventors: Ralph E Ton. New Malden; 2,420,677 5/ 1947 Peterson ..61/48 2,991,841 7/ 1961 Sampson et al ..182/1-39 Juncker Zelo Nicolaisen, Crawley, b th ofEn and 3,464,214 9/1969 King ..61/48 g 2,424,635 7/1947 Schwall ..61/48 [73] Assignee: Andre Rubber Company Limited, 3,379,020 4/1968 Krug ..61/48 X sma -Pes k vtbit o ,9551. England Primary Examiner-David J. Williamowsky Assistant Examiner-David H. Corbin [221 mm AttorneySughrue, Rothwell, Mion, Zinn & Macpeak [21] Appl. No.: 5,430

, [57] ABSTRACT [30] Foreign Application Priority Data A fender arrangement for a jetty, dockside, dolphin or 2 69 the like comprising a fender mounted for load-absorb- Jan. 23, Great Britain ..3,86 i g mo wa the g of the g st the action of normally unstrained elastomeric tension [52] US. Cl ..61/46, 61/48 springs in the form of endless bands looped between [51] Int. Cl. ..E02b 3/22 mounting pedestals carried by the jetty and the fender Field of Sear h 114/219, 220, 230; The fender may be slender driven piling or bodily car- 267/73, 153; 182/139 ried and guided by the jetty. Tension springs of elastomeric material show specified advantages over [56] Re e Cited compression and shear springs in jetty fenders.

UNITED STATES PATENTS 646,553 4/1900 Holmes ..61/48 1,145,749 7/1915 Claud ..l14/219 8 Claims, 8 Drawing Figures [Ll] I r I I I II I 11 O PATENTEU UT 3 I972 SHEET 3 UF 3 FENDERS BACKGROUND OF THE INVENTION Field of the Invention and absorb loads due to the arrival, departure and mooring of ships alongside the jetty.

SUMMARY OF THE INVENTION According to the invention in one aspect there is provided a load absorbing arrangement comprising a fender adapted to be arranged for movement towards and away from a generally rigid structure to be protected, and elastomeric tension spring, first means mounting a portion of said spring for movement with the fender, and second means mounting another portion of said spring, said second means being adapted to be secured to a generally rigid structure to be protected, whereby in use movement of the fender towards the structure causes movement of said first and second means away from one another to extend the spring.

According to the invention in another aspect there is provided a fender arrangement for a jetty or the like comprising a fender mounted for movement towards an edge of the jetty against the action of an elastomeric tension spring.

The arrangement is preferably such that the spring is substantially unstrained when the fender is in its unloaded condition.

In one application of the invention the generally rigid structure would be a structure it is desired to protect from shock loadings due to waterborne vessels and as such the structure would generally be mounted to the bed of a stretch of fresh or sea water or to the shore or bank adjacent the water and extending into the water. Such structures include jetties, quays, piers, harbor walls, mooring dolphins, channel markers, and lighthouse and bridge foundations and will be referred to herein as jetties and the like. Fenders according to the invention might also have some application on certain classes of waterborne vessels, such as tugs or' barges, in which case the rigid structure is the vessel.

In the application of the invention to jetties or the like, the fender may comprise slender piling driven into the water bed adjacent the jetty, the cross-sectional dimensions of the piling being chosen such that the piling can flex at its upper end towards and away from the jetty according to the expected loading. Alternatively the fender may be arranged so that in use it is carried by the rigid structure in a manner permitting bodily movement of the fender towards and away from the structure. In addition the fender is preferably carried so that it articulate to a limited extent about an axis in the general plane of the fender. Preferably the fender is rotatable to a limited extent (up to or even about two such axes, one axis being horizontal and the other vertical whereby the fender can accommodate itself to varying vessel side inclinations and to varying angles of orientation of the vessels longitudinal axis.

The elastomeric tension springs could be single lengths, strands, cylinders or tubes of elastomeric material, suitably with enlarged and reinforced ends to facilitate securing to the spring mounting means. The

springs can alternatively be directly bonded to appropriate metal parts. Alternatively and preferably endless bands of elastomeric material may be employed, the bands having any suitable cross-section and overall relaxed shape. There may be a slight tendency to fretting of the bands where they pass over their mountings, e.g., shafts or shackle bolts, but this can be alleviated by the use of suitable materials, and/or reinforcement, and/or shape, and/or lubrication.

It will be appreciated that an essential feature of the present invention involves the use of elastomeric material, such as natural or synthetic rubber, which, at least during fendering, is in tension between the fender and the rigid structure. The use of rubber in compression to absorb loads has been proposed in a number of Applications, one reason being that it is generally thought in the engineering field that rubber in tension has a tendency to crack and fail under sustained stress. In arrangements according to the present invention the rubber springs can be arranged to be unstressed or only lightly stressed while the fender is in its unloaded condition, thereby substantially avoiding problems associated with sustained stress and also giving the advantage of maximum average energy absorption per unit of rubber employed. Normally the duration of each fender operation would be measurable in fractions of a minute. Finally a tension spring arrangement is in itself stable and can readily be arranged so that the springs can be strained to several times their static length during fendering.

A plurality of springs would normally be provided between the fender and a structure. Springs arranged so that loading is applied in the direction of the spring would exhibit stress/strain curves, according to the elastomer employed, which would directly determine the fender characteristics, provided the springs are of equal length and pick-up load in unison. However, in particular applications the springs may be of different lengths and/or of different elastomers and/or be arranged to pick up loads at different travel positions of the fender and/or be arranged in different inclinations, I

so that the fender characteristics can be modified as desired.

In summary two main advantages of elastomeric tension springs as opposed to other springs such as shear or compression springs in fenders are firstly that a much greater energy input per unit volume can be obtained and secondly that much larger strains at uniform stress are possible.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

FIG. 1 is a vertical section through part of a jetty and a fender arrangement according to the invention on line A--A of FIG. 2,

FIG. 2 is a section on line B-B of FIG. 1,

FIG. 3 is a perspective view of another embodiment of the invention,

FIGS. 4 and 5 are fragmentary views of part of the fender of FIG. 3, FIG. 4 being a section on line C--C of FIG. 5, and

FIGS. 6, 7 and 8 are a plan and respective side elevations of a further embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2 there is shown a jetty having piling and an overhanging deck 11. First spaced mounting pedestals 12 are secured beneath the deck 11 and serve to support a shaft 13 parallel to and spaced beneath the deck edge. The shaft may be withdrawn from the pedestals to facilitate assembly. Adjacent to andspaced from the jetty piling there is provided a ship fender in the form of slender driven fender piling, suitably of timber, one pile of which is shown at 14. Piles 14 are sufficiently slender to bow or flex towards the jetty under loading. At its upper end pile 14 carries a pair of rearwardly extending spaced metal brackets 15 having a strengthening and guiding flange 16. The rearward ends of the brackets serve as second mounting pedestals 17 to carry a second shaft 18 arranged parallel to the first shaft 13. As shown in FIG. 2 the second mounting pedestal 17 is guided laterally between adjacent first pedestals 12. Endless rubber bands 19 loop over the two shafts, those in the upper half of FIG. 2 being removed for clarity. The bands are of such length as to be substantially unstressed when the fender is in its unloaded condition.

In operation when a vessel brushes or rides against fender 14 the fender 14 bows towards the jetty moving shaft 18 rearwardly away from fixed shaft 13. This causes the bands 19 to strain in tension to build up a stress equal and opposite to the fender loading whereby to absorb the vessel loading. The travel deflection of the top of the fender 14 is shown by distance T in FIG.

Referring to FIG. 3 there is shown a fender in the form of a timber faced framework 30 and a massive tubular cross spaced rearwardly of the framework, the cross having two opposed vertical arms 31 and two opposed horizontal arms 32. The cross is removably mounted to the framework 30 by suitable truss members 33. Four similar mounting and guiding pedestals 34 are secured to the seaward face of a jetty (not shown), one pedestal being associated with each of the four arms of the cross. Three pedestals have been removed from the figure for clarity.

The illustrated pedestal 34 comprises two similar braced

right corner assemblies

35, 36 spaced apart vertically back to back to define a horizontal guideway 38 for rearward movement of the associated

cross arm

31 or 32. The remaining three pedestals are similar, though turned through one, two and three right angles respectively to provide guideways for the four cross arms. The forward spaced ends of the two

assemblies

35, 36 carry a removable shaft 39 forward of and parallel to the associated

cross arm

31 or 32. A plurality of adjacent rubber bands 40 are looped between each shaft 39 and its associated

cross arm

31 or 32.

It will be seen that the weight of the fender is to some extent borne by the cross arms 32 travelling in guideways 38 and that the fender is to some extent similarly laterally located by cross arms 31 travelling in the vertical guideways (not shown). Buoya'ncy of the fender, depending on the water level, would also bear some of the fender weight to prevent it tilting forwardly, but preferably suitable auxiliary stops, rubber pads, buffers and/or chains or the like are provided loosely to restrain and stabilize the fender in its desired vertical position, as shown, when unloaded.

In operation distributed loading due to a vessel as shown by arrows 41 would strain the bands 40 in tension, rearward motion of the fender towards the jetty being guided by the four guideways 38. It will be seen that the fender can also rotate to a limited extent (e.g., 10 to 20) in either sense about both axes A and B lying in the axes of the

cross arms

31 and 32, whereby the fender facing can align itself with the vessel side the better to accommodate and distribute the vessel loading. Forces parallel to the jetty caused by the ship rolling or dragging on the fender are transferred to the jetty by the

cross arms

31 and 32 bearing against the sides of the appropriate guideways 38.

Referring to FIGS. 4 and 5 there is shown in more detail a fender spring and spring mounting assembly, similar reference numerals being used for similar parts in FIG. 3 for convenience, though this illustrated assembly could have other fender applications than the arrangement of FIG. 3. Basically the two spring mounting pedestals comprise a steel bracket forming part of and joining

corner assemblies

35, 36 and second steel brackets 51 secured to trusses 33. Shaft 32 is removably carried by brackets 51 and guided in guideway 38 formed as spaced elongate slots in the two side plates 52 of bracket 50. A forked web 53 extends between side plates 52 for strength. The side plates 52 carry half round elastomeric rubbing strips 52 at their forward end and side plates 55 of bracket 51 similarly carry half round rubbing strips 56 at their rearward end to reduce chaffing together of

side plates

52 and 55 during fendering.

Referring now to FIGS. 6, 7 and 8 there is shown a breasting dolphin respectively in plan view and two mutually perpendicular side elevations. In FIG. 8 part is removed and the view is in fact on line B-B of FIG. 6. The dolphin comprises a substantially generally box shaped framework 60 mounted on piling 61 and carrying a ship fender in the form of a generally rectangular box 62, without lid or bottom, surrounding the dolphinframework 60 and suspended from the uppermost part 63 of framework60 by two chains 64. The box 62 is preferably framed by members (not shown) extending through openings in framework 60 to enhance the structural strength of box 62. t

A plurality of sets of elastomeric tension springs extend between the fender and the dolphin framework 60. The springs include rows of

bands

65 and 66 which co-operate resiliently to oppose and absorb loads exerted on the fender to the left and to the right in FIG. 8. The loads exerted to the left on the right hand face of the fender would extend bands 65 into a state of tension. Bands 67 extend vertically between a lower member of the fender and the dolphin and provide resilient opposition to vertical upward movement of the fender caused for example by swelling seawater. This prevents the chains becoming too slack and avoids extreme shock loading on the chains when the swell subsides.

Bands

68 and 69 extend in two spaced horizontal parallel rows to absorb loading on the fender to the right in FIG. 7. Loading to the left in FIG. 7 is absorbed by four or more elastomeric buffers 70 mounted

adjacent band rows

68 and 69 for compression between the fender and the framework 60 when the fender is moved to the left in FIG. 7.

It will be appreciated that the illustrated fender is constructed primarily to absorb loading from the left in FIG. 7 (by bands 68 and 69) due to shipping buffing against this left hand face 71 of the fender which is appropriately shaped. Longitudinal rubbing by a ship against face 71 would be absorbed by

bands

65 and 66, and vertical rubbing by bands 67 in co-operation with the weight of the fender opposed by chains 64 and any buoyancy of the fender depending on the water level. All the bands co-operate to absorb the normal loading and fretting due to wave action and other water movement loading which may effect the fender..

The two chains 64 diverge outwardly from their point of suspension as shown in FIG. 8. This arrangement in co-operation with

bands

65 and 66 assists in stabilizing the fender in its neutral position. The chains 64 are also inclined in the same sense upwardly from their point of suspension on the fender, which lies substantially in the vertical plane including the center of gravity of the fender. This is shown in FIG. 7 and it will be apparent that the chain tension and the weight of the fender give a resultant force urging the inner face of wall 72 of the fender firmly against the buffers 70, whereby to minimize fretting movement of the fender due to wave action.

in this, as in the other described embodiments, the springs may be arranged between the fender and the rigid framework in a manner and pattern to suit the desired application and the expected direction or directions of ship loading. Moreover more than two chains 64 may be employed. It is preferable, particularly where more than two chains are used that the chains incorporate in their length or their mountings, one or more flexible units whereby to reduce high stresses due to shock loadings.

We claim:

1. In a marine jetty fendering arrangement for use with vessels, a jetty comprising a generally rigid structure mounted to the sea bed and having a generally horizontal forward edge above sea level;

a fender arrangement for protecting said jetty structure from any shock loadings due to impacts from vessels, said fender arrangement comprising a ship fender having a generally vertical load receiving face, said face extending substantially forwardly of and parallel to said jetty edge;

support means associated with said jetty, said support means carrying the fender for movement of the fender relative to the jetty structure in a general direction perpendicular to said jetty edge, said fender including a rearwardly extending portion extending rearwardly a substantial distance behind said forward edge of the jetty;

a plurality of elastomeric tension spring means;

first mounting means connected to each said spring means, and

second mounting means connected to each said spring means, said first mounting means being secured to said rearwardly extending portion of said fender at a point more remote from said load receiving surface than said jetty edge, and said second mounting means being secured to said jetty structure at a point between said jetty edge and said first mounting means, said elastomeric tension springs comprising endless bands of elastomeric material encircling said first and second mounting means, whereby movement of the ship fender towards the jetty edge causes movement of said first mounting means rearwardly further away from said second mounting means to strain elastomeric tension spring means substantially purely in tension to absorb the energy of any shock loadings on said fender thereby protecting said jetty against the effects of impact by vessels.

2. A jetty fendering arrangement according to claim 1, where said elastomeric tension spring means includes loops of rubber material connecting said jetty and fender arrangement.

3. A jetty fendering arrangement according to claim 1, wherein said support means includes a plurality of pairs of guide members, and wherein said rearwardly extending portion of said fender includes a plurality of arms, each arm having a first portion of its length being guidingly received between a respective pair of said guide members, said guide members defining and permitting generally horizontal movement of said fender with respect to said jetty with said arm portions sliding in said pairs of guide members, whereby said spring means return said fender to a rest position so that said spring means are substantially unstrained in the absence of loading.

4. A marine jetty fendering arrangement according to claim 3, wherein said first mounting means comprises a second portion of the length of each of said plurality of fender arms, said second mounting means comprises spaced mounting pedestals secured to said jetty structure and shaft means extending between said pedestals.

5. A marine jetty fendering arrangement according to claim 4, wherein said fender arms comprise .a horizontal cross arm and a vertical cross arm centrally intersecting said horizontal arm, said horizontal cross arm being guided by two pairs of said guide members disposed adjacent opposite ends of said arm, and said vertical cross arm being guided by two pairs of said guide members disposed adjacent opposite ends of said arm, whereby said fender is capable of rotation to a limited extent both about the horizontal axis defined by said horizontal cross arm and about the vertical axis defined by said vertical cross arm, whereby the load receiving surface of said fender can align and accommodate itself to the varying inclinations of the side of a vessel impinging on said fender.

6. A marine jetty fendering arrangement according to claim 5, wherein said fender is constructed of timber, the buoyancy of said fender serving to bear a proportion of the weight of said fender.

7. In a marine jetty fendering arrangement for waterborne vessels, a jetty comprising a generally rigid structure mounted to the sea bed and having a generally horizontal forward edge above sea level;

a fender arrangement adapted to protect said jetty structure from any shock loadings due to impact by waterborne vessels, said fender arrangement comprising a row of driven piling driven generally vertically into the sea bed a short distance in front of said jetty, said row being generally parallel to said jetty edge, said piles being slender and adapted to flex towards and away from the edge of the jetty without themselves offering much resistance to shock loading by waterborne vessels;

a bracket secured to each said pile, said bracket extending rearwardly a substantial distance behind said forward edge of the jetty;

a plurality of elastomeric tension springs;

first mounting means mounting a first portion of each said spring, and

second mounting means mounting a second portion of each said spring, said first mounting means being secured to the rearward end of said rearwardly extending bracket, and said second mounting means being secured to said jetty structure at a point between said jetty edge and said first mounting means, said elastomeric tension springs comprising endless bands of rubber material encircling said first and second mounting means whereby in use flexing movement of the fender piles towards the jetty edge causes movement of the first mounting means rearwardly further away from said second mounting means to strain said elastomeric tension springs substantially purely in tension to absorb the energy of any shock loadings on said fender thereby protecting said jetty against the effect of impact by waterborne vessels.

8. A marine jetty fendering arrangement according to claim 7, wherein said slender piles are driven into the sea bed at such a distance in front of the jetty that when the piles are in a neutral unflexed condition in the absence of loading then the elastomeric tension springs are in a substantially unstrained condition.

Claims

1. In a marine jetty fendering arrangement for use with vessels, a jetty comprising a generally rigid structure mounted to the sea bed and having a generally horizontal forward edge above sea level; a fender arrangement for protecting said jetty structure from any shock loadings due to impacts from vessels, said fender arrangement comprising a ship fender having a generally vertical load receiving face, said face extending substantially forwardly of and parallel to said jetty edge; support means associated with said jetty, said support means carrying the fender for movement of the fender relative to the jetty structure in a general direction perpendicular to said jetty edge, said fender including a rearwardly extending portion extending rearwardly a substantial distance behind said forward edge of the jetty; a plurality of elastomeric tension spring means; first mounting means connected to each said spring means, and second mounting means connected to each said spring means, said first mounting means being secured to said rearwardly extending portion of said fender at a point more remote from said load receiving surface than said jetty edge, and said second mounting means being secured to said jetty structure at a point between said jetty edge and said first mounting means, said elastomeric tension springs comprising endless bands of elastomeric material encircling said first and second mounting means, whereby movement of the ship fender towards the jetty edge causes movement of said first mounting means rearwardly further away from said second mounting means to strain elastomeric tension spring means substantially purely in tension to absorb the energy of any shock loadings on said fender thereby protecting said jetty against the effects of impact by vessels.

5. A marine jetty fendering arrangement according to claim 4, wherein said fender arms comprise a horizontal cross arm and a vertical cross arm centrally intersecting said horizontal arm, said horizontal cross arm being guided by two pairs of said guide members disposed adjacent opposite ends of said arm, and said vertical cross arm being guided by two pairs of said guide members disposed adjacent opposite ends of said arm, whereby said fender is capable of rotation to a limited extent both about the horizontal axis defined by said horizontal cross arm and about the vertical axis defined by said vertical cross arm, whereby the load receiving surface of said fender can align and accommodate itself to the varying inclinations of the side of a vessel impinging on said fendeR.

7. In a marine jetty fendering arrangement for waterborne vessels, a jetty comprising a generally rigid structure mounted to the sea bed and having a generally horizontal forward edge above sea level; a fender arrangement adapted to protect said jetty structure from any shock loadings due to impact by waterborne vessels, said fender arrangement comprising a row of driven piling driven generally vertically into the sea bed a short distance in front of said jetty, said row being generally parallel to said jetty edge, said piles being slender and adapted to flex towards and away from the edge of the jetty without themselves offering much resistance to shock loading by waterborne vessels; a bracket secured to each said pile, said bracket extending rearwardly a substantial distance behind said forward edge of the jetty; a plurality of elastomeric tension springs; first mounting means mounting a first portion of each said spring, and second mounting means mounting a second portion of each said spring, said first mounting means being secured to the rearward end of said rearwardly extending bracket, and said second mounting means being secured to said jetty structure at a point between said jetty edge and said first mounting means, said elastomeric tension springs comprising endless bands of rubber material encircling said first and second mounting means whereby in use flexing movement of the fender piles towards the jetty edge causes movement of the first mounting means rearwardly further away from said second mounting means to strain said elastomeric tension springs substantially purely in tension to absorb the energy of any shock loadings on said fender thereby protecting said jetty against the effect of impact by waterborne vessels.