A coupling

Abstract: A coupling (1, 50, 100) for joining adjacent frame members (2, 3) of a fish breeding enclosure (5) comprises a first mounting means (10, 52, 105, 106) for mounting to one frame member (2), a second mounting means (11, 53, 105, 106) for mounting to another frame member (3) and a flexible body (12, 51, 101) of elastomeric material between the first and second mounting means (10, 11, 52, 53, 105, 106). The coupling (1, 50, 100) constrains relative rotational and translational movement between the frame members (2, 3) in use to a predetermined level which is determined by the material of the flexible body (12, 51, 101) and/or by mechanical limit stops (62, 63). A non flexible connection such as a rod (35) having flanges (36, 37) or a chain (90, 110) provides a mechanical connection between the mounting means (10, 11, 52, 53, 105, 106) in the event of failure of the flexible body (12, 51 , 101).

Description: The invention relates to a fish breeding enclosure coupling for joining frame members of a fish breeding enclosure framework to permit controlled movement between adjacent frame members in use. More particularly, the invention relates to a coupling of this type comprising: a first mounting means for mounting to a frame member; a second mounting means for mounting to a frame member; and a connecting body of flexible material between the first and second mounting means; the first mounting means having a first outer casing part; the second mounting means having a second outer casing part; the connecting body comprising at least two axially aligned flexible body parts; and the coupling including: a housing for confining each flexible body part; each housing comprising an inner housing part defining a bore, the bores of the inner housing parts being aligned to form a central longitudinally extending bore; a retaining rod extending axially through the central longitudinally extending aligned bores of the inner housing; and the bore and rod being shaped to prevent relative rotational movement between the inner housing parts, in use. GB-A-2,027,162 describes a coupling of this type. Fish breeding enclosures comprising a framework formed by interconnecting frame members are known. In one known arrangement the frame members are pivotally interconnected by a pivot pin arrangement for pivotal movement about a pivot axis transverse to the longitudinal axis of the frame member to which it is attached. However, the forces which such enclosures can accommodate are relatively small so that such enclosures have limited application both in terms of their size and in the waterways in which they may be sited. WO 87/03170 describes a fish breeding enclosure incorporating a breeding bag carried by a cage comprising a three dimensional framework of rods which are interconnected by joints which can be made from an elastic material such as a reinforced elastomeric material. The invention is characterised in that said housing also comprises an outer housing part for fitting into a respective one of the first and second outer casing parts of the first and second mounting means, the inner and outer housing parts being radially spaced-apart to confine the respective flexible body part therebetween, each outer housing part including a radially outwardly extending flange for locating and limiting the entry of the outer housing part into an associated casing part; and washer means on the rod which extend radially outwardly to engage, in use, the outer casing part of the respective mounting means. Preferably the inner housing part and the associated flexible body part extends axially beyond at least one end of the outer housing part to permit relative translational movement between the flexible body parts in shear and compression along the axis of the flexible body parts, the ends of the outer housing parts providing limit stops to limit the movement of the flexible body parts, in use. Preferably the inner bores defined by the inner housing parts are polygonal in transverse cross section and the connecting rod is of complementary polygonal shape for distributing loads applied to the frame members between the flexible body parts. Typically the flexible body part is disposed on an axis which is inclined with respect to the longitudinal axis of the bore. In this case preferably the longitudinal axes of the material of adjacent flexible body parts are inclined with respect to each other. In a particularly preferred embodiment of the invention the outer casing comprises a central casing part associated with one frame member and the second outer casing part comprises a pair of side casing parts flanking the central casing part and being associated with another frame member. In one case the central casing part is approximately twice the width of each side casing part, there being four identical housing parts, one within each side casing part and two within the central casing part. The invention also provides a framework for a fish breeding enclosure incorporating a coupling according to the invention between the frame members of the framework. Preferably there are at least two spaced-apart couplings between adjacent frame members of the framework. The invention also provides a fish breeding enclosure having a framework incorporating couplings according to the invention. The invention will be more clearly understood from the following description thereof given by way of example only with reference to the accompanying drawings in which: Fig. 1 is a plan, partially cross sectional view of a coupling according to one embodiment of the invention, Fig. 2 is a perspective view of the coupling of Fig. 1, in use, Fig. 3 is a side elevational view of part of the coupling, Fig. 4 is a perspective view from one side of one part of the coupling. Fig. 5 is a perspective view from the other side of the coupling part, Fig. 6 is a cross sectional view of the coupling part of Figs. 4 and 5,. Fig. 7 is a plan view of a typical layout of a fish breeding enclosure incorporating the couplings of the invention, Fig. 8 is a plan view of a layout of another fish breeding enclosure incorporating couplings according to the invention, Fig. 9 is a view on line IX IX in Fig. 8. Referring to the drawings and initially to Figs. 1 to 9 thereof there is illustrated a coupling according to one embodiment of the invention and indicated generally by the reference numeral 1. The coupling 1 is used for joining adjacent frame members 2, 3 of a fish breeding enclosure 5. It will be noted that in this case a central longitudinal axis L of the coupling 1 is arranged substantially transversely of the adjacent frame members 2, 3 to which it is attached. Some typical layouts of fish breeding enclosures incorporating the couplings 1 according to the invention are illustrated in Figs. 7 to 9. Referring in particular to Figs. 1 to 6 the coupling 1 in general terms comprises a first mounting means 10 for mounting to one frame member 3 and a second mounting means 11 for mounting to another adjacent frame member 2. A flexible body of elastomeric material is provided between the first and second mounting means 10, 11 and the arrangement is such that the coupling 1 allows controlled relative rotational and translational movement between the frame members 2, 3 in use to a predetermined level. As will be described in more detail below the means for constraining the relative rotational and translational movement between the frame members 2, 3 is in some cases provided by the properties of the elastomeric material of the flexible body and in other cases by mechanical stops. The connecting body is divided into at least two flexible body parts, in this case two pairs of flexible body parts, namely a central pair of flexible body parts, 15, 16 associated with the first mounting means 10 and an outer pair of flexible body parts 17, 18 flanking the central pair of flexible body parts and being associated with the second mounting means 11. The central body parts 15, 16 are confined within a first outer central casing part 20 which forms the first mounting means 10 or to which the first mounting means 10 is rigidly secured. The outer flexible body parts 17, 18 are confined within second outer side casing parts 21, 22 respectively which form the second mounting means 11 or to which the second mounting means 11 is rigidly secured. In this case and referring particularly to Figs. 4 to 6 each flexible body part, for example, the flexible body part 15 is confined within a housing which comprises an inner housing part 25 and an outer housing part 26 which are radially spaced-apart to confine the flexible body part 15 therebetween. The outer housing part 26 is a force fit in the associated outer casing part 20, 21 or 22 and includes a radially outwardly extending flange 29 which, in use, locates and limits the entry of the outer housing part 26 into an associated casing part 20, 21. Each inner housing part 25 has a central longitudinally extending axial bore 30 which is preferably of polygonal shape, in this case, hexagonal shape, the bores 30 of each of the four inner housing parts 25 being arranged co-axially as illustrated in Fig. 1 to form a central longitudinally extending hexagonal bore through the coupling 1. Connection means are provided between the flexible body parts to constrain translational movement between the body parts in use and in this case the connecting means comprises an elongate rod 35 of complementary hexagonal shape to that of the bore, the rod having radially outwardly extending washers or flanges 36, 37 which extend in use to engage the vertical side edges of the second outer casing parts 21, 22 as will be apparent from Fig. 1. The rod 35 may be screw threaded or in this case includes screw threaded extension portions 38, 39 on which the washers 36, 37 are mounted and fixed in position by lock nuts 40. The effect of the rod 35 is to distribute load forces applied between the flexible body parts 15, 16, 17, 18. It will be noted that each inner housing part 25 extends axially beyond at least one end of the outer housing part 26 to permit relative translational movement between the flexible body parts in shear and compression along the longitudinal axis, the ends of the outer housing parts 26 providing limit stops to limit the movement of the flexible body parts in compression. It will also be noted that the inner housing part 25 is recessed with respect to the outer housing part 26 at the non-flanged end thereof to accommodate translational movement of the flexible body part 15. It will also be noted from Fig. 6 that the longitudinal axis of each of the flexible body parts is inclined with respect to the longitudinal axis L and the longitudinal axes of adjacent flexible body parts are inclined with respect to each other for accommodating loads applied to the flexible body parts, in use. For ease of manufacture, assembly and maintenance, there are, it will be appreciated, in the configuration just described, four identical parts illustrated in Figs. 4, 5 and 6 which are assembled as illustrated in Fig. 1 and 3 into the first outer central casing part 20 and the second outer side casing parts 21, 22 so that the flanges 29 are facing each other. The hexagonal rod 35 is then inserted through the bores 30, the washers 36, 37 fitted and fixed in position by the lock nuts 40. The first and second mounting means 10, 11 are then attached to the frame members 2, 3 which are arranged to form a fish breeding enclosure 5 of any desired shape and configuration such as the configurations illustrated in Figs. 7, 8 and 9. Generally there will be two couplings provided at the joint between adjacent frame members. It will be appreciated that the shape and configuration of the mounting arrangement, for example, through a flange and bolting arrangement or any suitable means is selected to achieve any desired configuration of enclosure. The couplings facilitate mounting in many different orientations as desired. In use, the fish breeding enclosure incorporating the couplings 1 is mounted in a waterway and bending, tensile and shear forces developed in use are accommodated by the coupling without excessive wear or damage to the frame member and/or the couplings. Thus, the enclosures formed using the couplings of the invention can take up the forces developed in rough weather when sections of the enclosure will be moved a significant distance with respect to an adjacent section in response to waves and water currents generally. The arrangement in this case is such that relative rotational and translational movement between the frame members 2, 3 of the enclosure in use are constrained by the configuration, by mechanical stop means, and by the properties of the elastomeric material forming the flexible coupling parts to predetermined levels. Compression forces along the longitudinal axis L of the coupling is taken up by the stability of the flexible body parts 15, 16, 17, 18 until adjacent flanges 29 abut, the flanges 29 effectively forming limit stops to limit the translational movement. Tension or extension forces along the axis L are taken up by the flexible body parts and are limited by the flanges 29 of the outer housing 26. The polygonal shape of the rod 35 and the bores in the inner housing parts 25 through which rod 35 extends has the effect of distributing forces applied to the frame members through the first and second mounting means 10, 11 to each of the flexible bodies. The general advantages of the couplings according to the various embodiments of the invention are outlined in detail below. Some particular advantages of this embodiment are that because the flexible body is divided it has the effect of allowing a thinner section of flexible body to be used. In tension forces applied are distributed between the parts. Preferably the material of the outer housing is non-metallic, most preferably of a non-metallic material which expands in sea water, such as nylon. The flexible body may be relatively easily bonded to such material and the housing can be made to achieve a good interference fit which improves in use by expansion in the sea water. The advantage of arranging the flexible body on an axis Lf which is inclined with respect to the longitudinal axis L is in providing improved axial stiffness in use. Thus, for a given load a shorter distance between the facing flanges 29 may be provided. A low friction material such as polytetrafluoroethylene (PTFE) may be bonded to the faces of the flanges 29 to limit frictional engagement. If a force is applied to the mounting part 10 which tends to rotate it about the axis L the force is spread between the parts and constrained by the stiffness of the flexible body parts. It will be appreciated that the rod 35 may have a limit stop welded thereto and may be assembled using any suitable arrangement such as by insertion through a washer which is fixed in place by a pin inserted through the rod. The advantages of all the embodiments of the invention are many. By flexibly connecting frame members of a fish breeding enclosure together the connections between the frame members can accommodate relatively large forces in a number of different directions. Thus, larger enclosures may be built and/or the enclosures may be sited in waterways which have heretofore not been used because of the large forces generated by water currents and waves in the waterway. The dynamic response of a fish breeding enclosure incorporating couplings according to the invention is substantially reduced. The couplings allow the geometry of the enclosure to change in both rotation and translation to accommodate water currents and waves passing through the enclosure without deformation in the frame members. We have found that the flexible body should allow a rotational movement between the frame members of up to 30°, preferably up to 26°. In each of the embodiments described above it will be apparent that there is no metal to metal contact which could cause wear in use. Thus, in addition to taking up forces applied by the water currents and waves in the water course in which the fish breeding enclosure is mounted, the couplings according to the invention will have a long life, in use. It is anticipated that the couplings according to the invention will facilitate the formation of much larger enclosures than has heretofore been possible.

Claims: A fish breeding enclosure coupling (1) for joining frame members (2,3) of a fish breeding enclosure framework to permit controlled movement between adjacent frame members in use, the coupling (1) comprising:- a first mounting means (10) for mounting to a frame member (3) a second mounting means (11) for mounting to another frame (2); and a connecting body (15, 16, 17, 18) of flexible material between the first and second mounting means (10, 11); the first mounting means (10) having a first outer casing part (20); the second mounting means (11) having a second outer casing part (21, 22); the connecting body (15, 16, 17, 18) comprising at least two axially aligned flexible body parts (15, 16, 17, 18); and the coupling including a housing (25, 26) for confining each flexible body part (15, 16, 17, 18); each housing (25, 26) comprising an inner housing part (25) defining a bore (30), the bores (30) of the inner housing parts (25) being aligned to form a central longitudinally extending bore (30); a retaining rod (35) extending axially through the central longitudinally extending aligned bores (30) of the inner housing parts (25); and the bore (30) and rod (35) being shaped to prevent relative rotational movement between the inner housing parts (25), in use; characterised in that, said housing (25, 26) also comprises an outer housing part (26) for fitting into a respective one of the first and second outer casing parts (20, 21, 22) of the first and second mounting means (10,11); the inner and outer housing parts (25, 26) being radially spaced apart to confine the respective flexible body parts (15, 16, 17, 18) therebetween; each outer housing part (26) including a radially outwardly extending flange (29) for locating and limiting the entry of the outer housing part (26) into an associated casing part (20, 21, 22); and washer means (36, 37) on the rod (35) which extend radially outwardly to engage, in use, the outer casing part (20, 21, 22) of the respective mounting means (10, 11). A coupling as claimed in claim 1 characterised in that the inner housing part (25) and the associated flexible body part (15, 16, 17, 18) extend axially beyond at least one end of the outer housing part (26) to permit relative translational movement between the adjacent flexible body parts (15, 16, 17, 18) in shear and compression along the axis (L) of the flexible body parts, the ends of the outer housing parts (26) providing limit stops to limit the movement of the flexible body parts (15, 16, 17, 18), in use. A coupling as claimed in claim 1 or 2 characterised in the inner bores (30) defined by the inner housing parts (25) are polygonal in transverse cross section and the connecting rod (35) is of complementary polygonal shape for distributing loads applied to the frame members (2,3) between the flexible body parts (15, 16, 17, 18). A coupling as claimed in any of claims 1 to 3 characterised in that the flexible body parts (15, 16, 17, 18) is disposed on an axis (Lf) which is inclined with respect to the longitudinal axis (L) of the bore (30) A coupling as claimed in claim 4 characterised in that the longitudinal axes (Lf) of the material of adjacent flexible body parts (15, 16, 17, 18) are inclined with respect to each other. A coupling as claimed in any of claims 1 to 5 characterised in that the first outer casing (20) comprises a central casing part (20) associated with one frame member (2), and the second outer casing part (21, 22) comprises a pair of side casing parts (21, 22) flanking the central casing part (20) and being associated with another frame member (3). A coupling as claimed in claim 6 characterised in that the central casing part (20) is approximately twice the width of each side casing part (21, 22), there being four identical housing parts (25, 26), one within each side casing part (21, 22) and two within the central casing part (20). A coupling as claimed in any of claims 1 to 7 characterised in that each outer housing part (26) includes a radially outwardly extending flange (29) for locating and limiting the entry of the outer housing (26) into an associated casing part (20, 21, 22). A fish breeding enclosure framework incorporating a coupling (1) as claimed in any preceding claim between frame members (2,3) of the framework.

Inventors: NOLAN TERENCE PATRICK, NOLAN, TERENCE PATRICK
Applicants: NOLAN TERENCE PATRICK, NOLAN, TERENCE PATRICK
Application year: 1989
Main classification: A01K61
IPC codes: A01K61, A01K63