GB2250412A - Fishing rods - Google Patents

Abstract

A fishing rod with a composite structure comprises a plurality of wrapped superposed layers (15, 16, 17, 18) of carbon fibre mesh or fabric which are inclined with respect to the axis of the rod. The resulting rod is of a circular external profile towards the two ends (11, 12) and a polygonal profile in the intermediate part (13). Wrapping of the layers is effected with a variable tension in the polygonal intermediate pant (13). The rod thus provides a satisfactory compromise between rigidity and resiliency without being too heavy. <IMAGE>

Description

METHOD OF MANUFACTURING FISHING RODS. AND A FISHING ROD PRODUCED BY SUCH A METHOD The present invention concerns an improved method of manufacturing fishing rods and a novel fishing rod which is produced by such a method.

As is known, there are many types of fishing rods, for example fixed, casting, "roubaisian", and "fly fishing", which are each suited to different fishing techniques.

At the present time the fishing rods which are most widely used are formed by a plurality of rod elements which are fitted one into the other end-to-end to give the desired length of rod and which are of progressively decreasing cross-section, the handle being the thickest and the tip the thinnest. Normally the cross-section of the various elements is circular and hollow.

Each element is made with a composite structure formed by layers of carbon fibre mesh or fabric or glass fibre mesh or fabric, which are impregnated with synthetic resin.

Manufacture of the elements normally involves using conical cores on which the layers are wrapped by means of suitable wrapping presses and then the elements which are produced in that way are covered with a strip of cellophane, polypropylene or the like. Finally, the resin impregnating the fabrics is polymerised by introducing the elements into a mould and heating them in an oven, preferably at low pressure.

The fishing rods are required to respond to two main requirements, which are mutually contradictory and which impart to each rod the specific technical characteristics which correspond to the particular use required.

The first requirement is that of rigidity, which is achieved by using a fibre layer of relatively high density (up to 130 g/m2) with fibres which are parallel to each other and to the axis of the rod. That layer however has poor resistance to compression or radial deformation.

Therefore, it is necessary also to apply one or more layers of relatively reduced density (up to 30 g/m2) with fibres which are disposed circumferentially, that is to say which are orthogonal relative to the axis of the rod.

The second requirement is that of resiliency or impact strength, which is achieved by increasing the thickness of the wall, that is to say the layers of fabric; however doing that means that the total weight of the rod is increased, so that sometimes it exceeds acceptable limits, in particular for very long rods, for example measuring 10 metres and more. As is known, increasing rigidity also increases the fragility of the rod.

In order to reconcile those contrasting requirements as regards rigidity and resiliency, it is possible to increase the overall cross-section, with the same wall thickness; however such a structure involves ergonomic limits since it reduces the ease of handling and increases the difficulties involved in assembling/dismantling the rod elements involving interengaging end formations. The use of meshes with intersecting fibres which are inclined with respect to the axis of the rod has also been tried, but that has not given any appreciable advantage as regards the compromise between rigidity and resiliency.

Japanese Patent Publication 84-039296 proposes a structure for golf clubs and fishing rods in which the rod elements are of a cross-section which varies in shape starting from one end of circular section which becomes elliptical and then becomes circular again at the other end.

A structure of that type affords adequate requirements in terms of rigidity and resiliency, but only along the two axes which are respectively orthogonal to each other, namely the major and minor axes of the elliptical section.

While that construction is valid in relation to golf clubs whose handles are precisely governed by the position of the head of the club, it is not acceptable for elements of fishing rods which can be fitted and held in any rotational position with respect to the axis of the rod.

It is therefore the object of the present invention to provide an improved method of manufacturing fishing rods, in such a way as to produce new fishing rods which do not suffer from the above-mentioned limitations and disadvantages and which provide a satisfactory compromise as between rigidity and resiliency without being penalised by an increase in weight.

Accordingly one aspect of the present invention provides a method of manufacturing a fishing rod of composite structure comprising the steps of:- cutting a fabric or mesh of carbon fibre or the like to produce strips preimpregnated with synthetic resin and of a length and a width corresponding to each rod element; applying at least two superposed said strips to a shaping core having a circular cross-section towards its two ends and a polygonal crosssection in the central part, along a wrapping direction which is inclined with respect to the axis of the core; and wrapping them around the core with a variable tension in the strip along said polygonal part; wrapping a strip of film around said wrapped impregnated strips; and finally, polymerizing the thus produced rod element in an oven.

A second aspect of the invention provides a fishing rod of composite structure having a hollow body with walls formed by layers of fabric or mesh which are wrapped in superposed relationship and embedded in resin; the crosssection of said body being variable from one end thereof to the other with a circular external profile towards the two ends and a section of a polygonal external profile in an intermediate part of the body.

The structural details and advantages of the invention will be more clearly apparent from the following description which is given by way of non-limiting example with reference to the accompanying drawings, in which: FIGURE 1 is a perspective view of a shaping core for the manufacture of a fishing rod element in accordance with the method of the invention; FIGURES 2 to 5 are respective views in crosssection taken along lines II-II, III-III, IV-IV and V-V of the core shown in Figure 1; FIGURE 6 is a partly sectional perspective view of a portion of the fishing rod produced in accordance with the method of the invention; FIGURE 7 is a view in cross-section on an enlarged scale of the portion of fishing rod shown in Figure 6; and FIGURES 8 and 9 show two details on a further enlarged scale from Figure 7.

Described hereinafter are:- the method of manufacturing a fishing rod according to the invention, and the novel fishing rod produced by that method.

The base material used is a carbon fibre fabric impregnated with synthetic resin, for example the fabric or mesh of type HYE with fibres M46 B and resin 948 M2 from Fiberite Europe of the ICI Group, or the fabric or mesh of type T6T 110 460 and resin EH 67 from Hexcel-Genin.

The fabric is initially cut in such a way as to form strips which are of a length and a width which respectively correspond to each rod element to be produced.

The procedure then involves applying the various layers of the fabric or mesh to a shaping core 10 (Figure 1) whose cross-sectional area progressively decreases from the end 11 which is nearer the handle, towards the end 12 which is nearer the tip of the rod.

In accordance with the invention, the shaping core 10 is of a cross-section whose shape varies from one end to the other; more precisely, that shape is circular towards the two opposite ends 11 and 12 and polygonal in the intermediate part 13. The variation in cross-sectional area and shape of the core 10 is clearly shown in Figures 2 to 5 which show respective sections of the core of Figure 1.

In the example illustrated the polygon for the intermediate part 13 is a regular hexagon.

The layers of fibre reinforcement which are wrapped around the core 10 to form the wall 14 (Figure 6) of the body of the rod are preferably four in number, namely:- (a) a first layer 15 with fibres having a high level of compression strength which are disposed in orthogonal relationship to the axis of the rod, (b) a second layer 16 and (c) a third layer 17 using fibres with a high level of compression strength which are disposed inclined at a maximum angle of 20 relative to the generatrix of the rod and are arranged in mutually opposite directions, and (d) a fourth layer 18 using fibres with a high coefficient of elasticity (tensile) which are disposed in orthogonal relationship to the generatrix of the rod.

Those layers are applied manually along a directrix of the shaping core 10 (Figure 1) and are successively wrapped therearound by means of an automatic orientableplane wrapping apparatus (not shown) of known type.

The structure which is produced in that way is then covered with a strip of regenerated cellulose known by the Registered Trade Mark Cellophane, polypropylene or the like by means of a roller-type taping apparatus (not shown) of known type which is provided with a friction control for varying the tension of the applied strip.

In accordance with the invention the strip-applying operation is effected with a constant tension in the circular cross-section part of the rod towards its two ends; the strip-applying tension is however varied in the polygonal part of the rod. More precisely the tension is relatively increased at the positions of the vertices B of the polygon and is relatively reduced along the sides A thereof (Figures 7, 8 and 9). In that way the wall thickness produced is smaller at the positions of the vertices B (Figure 9) since that produces greater stretching of the fibres and displacement of impregnating resin with respect to the sides A (Figure 8) of the polygon.

When the structure is completed, the result is that the fibres of the internal layer operate substantially in a compression mode while the fibres of the external layer operate substantially in a tensile mode. In other words the corners of the polygonal part constitute resilient hinges while the sides of the polygonal part constitute rigidityimparting elements of the rods.

The last phase in manufacture of the rod involves polymerisation of the rod element having been shaped as described above, by means of introducing it into an oven at a temperature of around 120 C and at a reduced pressure of less than 1 bar, in accordance with a procedure which is known to the man skilled in the art.

The method according to the invention thus makes it possible to produce a fishing rod which, besides involving a novel structure with a body of variable section which is in part polygonal, achieves the required compromise between the technical features of rigidity and resiliency.

The method according to the invention has been described with reference to the manufacture of an element for a fishing rod of "interengaging element" type, but it will be apparent that it may be applied to fishing rods of any type, imparting thereto the above-indicated advantages to which is added the advantage of reduced weight with other conditions being the same.

It will be appreciated that the hexagonal central cross-section configuration is the easiest to be produced, but it will be apparent that it is possible to provide configurations with a different number of sides while still complying with the condition that what is involved is polygonal configurations which do not impose a preferential axis of orientation, as would be the case for example of a centre section with an oval cross-section.

If then there is a wish to provide fishing rods which are heavier and stronger, it will be sufficient to apply a greater number of layers of fabric, while still complying with the particular mode of wrapping described above.

Although the term "roubaisian" used herein is well known in this art, for clarification we add that a roubaisian rod is unusually long (up to 13 metres) and is formed of 10 or 11 rod elements joined end-to-end. It is very light, stiff, and rugged.

Claims (11)

1. A method of manufacturing a fishing rod of composite structure comprising the steps of:- cutting a fabric or mesh of carbon fibre or the like to produce strips pre-impregnated with synthetic resin and of a length and a width corresponding to each rod element; applying at least two superposed said strips to a shaping core having a circular cross-section towards its two ends and a polygonal cross-section in the central part, along a wrapping direction which is inclined with respect to the axis of the core; and wrapping them around the core with a variable tension in the strip along said polygonal part; wrapping a strip of film around said wrapped impregnated strips; and finally polymerizing the thus produced rod element in an oven.

2. A method according to claim 1, wherein said wrapping tension at the position of said central part is relatively greater at the corners of the polygon and relatively lower at the positions of the sides of the polygon.

3. A method according to claim 1 or 2, comprising wrapping a first said layer with fibres which are orthogonal with respect to the axis of the rod element, a second said layer with fibres which are inclined with respect to said axis of the rod, and a third said layer with fibres which are inclined in the opposite direction with respect to that of the fibres of the second layer, said second and third layers being wrapped with the fibres inclined at a maximum angle of 20 with respect to the axis of the rod, and said first, second and third layers being formed by fibres which have a high level of compression strength.

4. A method according to any one of claims 1 to 3, wherein an outer said layer is wrapped in superposed relationship with the underlying layer or layers, the fibres of said outer layer being disposed parallel to the axis of the rod, and having a coefficient of tensile elasticity higher than that of the or each underlying layer.

5. A method according to any one of claims 1 to 4, wherein said film is regenerated cellulose, or polypropylene.

6. A fishing rod of composite structure having a hollow body with walls formed by layers of fabric or mesh which are wrapped in superposed relationship and embedded in resin; the cross-section of said body being variable from one end thereof to the other with a circular external profile towards the two ends and a section of a polygonal external profile in an intermediate part of the body.

7. A method according to any one of claims 1 to 5 or a fishing rod according to claim 6, wherein the polygonal cross-section is hexagonal.

8. A method according to any one of claims 1 to 5 or a fishing rod according to claim 6 or 7, wherein the polygon is a regular polygon.

9. A fishing rod according to claim 6, 7 or 8 having been produced by a method according to any one of claims 1 to 5.

10. A method of manufacturing a fishing rod, substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

11. A fishing rod constructed substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.