Classifications

• • A—HUMAN NECESSITIES
  • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
  • A01K—ANIMAL HUSBANDRY; AVICULTURE; APICULTURE; PISCICULTURE; FISHING; REARING OR BREEDING ANIMALS, NOT OTHERWISE PROVIDED FOR; NEW BREEDS OF ANIMALS
  • A01K91/00—Lines
  • A01K91/14—Leaders
  • A01K91/16—Leaders for fly fishing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C35/00—Heating, cooling or curing, e.g. crosslinking or vulcanising; Apparatus therefor
  • B29C35/02—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould
  • B29C35/04—Heating or curing, e.g. crosslinking or vulcanizing during moulding, e.g. in a mould using liquids, gas or steam
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
  • B29C55/22—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of tubes

Definitions

• the 'leader' or 'cast' in fishing is normally a length of line that is at or near the terminal or hook end of the tackle.
• a leader is required to possess a number of qualities such as strength, suppleness, weight distribution for casting, durability, abrasion resistance, particular floating/sinking characteristics and camouflage.
• the types of leaders used in fishing today may take one of a number of forms : -
• Knotted tapered leaders These have been used for well over 100 years (although only recently in nylon of course) and consist of knotting various lengths of different gauge monofilaments together so as to form a stepped taper from the main line down to the hook. Such leaders cast better than simple level monofilament leaders but have highly visible knots that often tangle. Also they have butt ends which tend to be too stiff for good turnover of the cast and hence have poor presentation.
• Knotless tapered monofilament leaders are extruded to form a continuous knotless taper and are normally made of nylon with added chemicals so as to improve strength and prevent water absorption. Such leaders having a single monofilament butt either do not have sufficient weight to produce good turnover or, if they are made of sufficient diameter to give the weight, they are then too stiff to produce a good turnover and convey the energy smoothly down to the bait or fly.
• leader in fly fishing the leader requires the mass to be able to convey the energy from the fly line to the tippet and hence fly. But with the normal monofilament type of leaders, increasing the diameter (to achieve the required mass) increases the stiffness to the power of 4 of that diameter and the leader rapidly becomes too stiff to use. Ideally, of course, the leader should combine all the good points suggested above whilst avoiding the undesirable characteristics .
• a method of tapering a fishing line whose surface layer, at least, consists of a thermoplastic material, comprising subjecting the line to heat over a predetermined length and then reducing that length from one end by relative movement of the heat source and the line while maintaining a tension on the surface layer to stretch that part of the layer softened by the heat and thereby taper said length.
• the heat source is a bath of heated liquid.
• the line is initially immersed over said predetermined length in the liquid, and is then gradually withdrawn while being held under tension.
• the portion that emerges from the liquid first will solidify from a plastic state created by the heat, but not before the tension has stretched it a bit and reduced its thickness.
• Continuous withdrawal creates a taper which will be progressive down to the last portion remaining in the liquid. That will remain heated longest, and therefore stretch and thin the most.
• the line may be held upright between means that are urged apart during upwards movement from the bath to create the tension.
• initially the line slopes down into the bath at an acute angle. The lower end is immersed while the upper end is drawn up and away from the lower end.
• More than one line can be stretched and tapered simultaneously, using a common heat source.
• the lines may be the legs of an extended length of line material arranged in a zig-zag fashion. After the heat and tensioning treatment, the extended length is severed at the turns of the zig-zag to produce a multitude of tapered leaders.
• the surface layer may be a tube, m which case it could be a sheath for a core of different material.
• This core may be present when the surface layer is stretched and tapered, and if it is substantially inextensible, the sheath will creep relative to it when stretched and tapered.
• the core may be threaded through the line after the sheath is stretched and tapered.
• the ends of the tube are sealed around the core.
• the tube comprises the line, which after stretching and tapering is sealed at its ends.
• the line is not hollow, but solid all through of the same material .
• the line will initially be of uniform cross- section, but it could have an existing taper which is modified by this method.
• Figure 1 is a diagram of a tapering apparatus for fishing lines
• FIG. 2 is a diagram of a modified tapering apparatus
• Figure 5 is an axial section of another tapered leader.
• a bath 1 contains liquid 2 which is heated to somewhere in the range 120° - 150°C, typically, for most suitable polymers.
• a carriage 3 can move vertically in and out of the bath and is equipped with clamps 4 and 5 at top and bottom to hold a short line 6 which is to become a tapered leader. Its coating or surface layer, at least, is of thermoplastic material .
• the lower clamp 5 is fixed to the carriage, but the upper clamp 4 is moveable with respect to the carriage to increase the distance between itself and the lower clamp 5 as the carriage 3 is raised from the lowered position shown.
• the clamp 10 is just above the surface of the liquid 9 and a line 11 is held taut between it and the clamp 8, which is immersed.
• the clamp 10 is then moved upwards, following its assigned path, and so the line 11 is gradually brought clear of the liquid 9 while being stretched. A taper is therefore created.
• the bath 7 could be widened and the clamps multiplied or the zig-zag technique adopted to accommodate a number of parallel lengths of line 11.
• Figure 4 illustrates one type of tapered line, having a monofilament core 12 closely encased in a plastics sheath 13 which was originally cylindrical as indicated in broken lines.
• the sheath will be low modulus polyurethane, which may be loaded to alter its density in known manner.
• the radial dimension is much exaggerated in relation to the axial direction for clarity.
• the taper of the sheath is achieved as described above, the core 12 being left free of the clamps so that the sheath 13 can creep lengthwise relative to it.
• the line may be completely of thermoplastics material, without a core. It may also be tubular as illustrated m Figure 5. After tapering, the tube 14 may be threaded by a core 15, conveniently nylon monofilament, and its ends will then be sealed by welding or glue, for example. But again, the core 15 is optional.
• Substantially transparent or clear lines and leaders are often considered desirable, and there are thermoplastic materials available to make transparent lines and leaders according to the methods described.
• the invention is not so limited.
• the line may already have a simple taper, having been manufactured by known methods.
• the process described above can be employed to modify that basic taper to a different, more complex profile.
• the heated bath gives a precise interface between the plastics-so tening environment and the cooling air which hardens the material.
• other heating agents may be employed.
• the line may be drawn out of a hot air tube at a controlled rate, or past a microwave heater.

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• Life Sciences & Earth Sciences (AREA)
• Environmental Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Health & Medical Sciences (AREA)
• Oral & Maxillofacial Surgery (AREA)
• Thermal Sciences (AREA)
• Marine Sciences & Fisheries (AREA)
• Animal Husbandry (AREA)
• Biodiversity & Conservation Biology (AREA)

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• 1996
  • 1996-03-16 GB GBGB9605560.3A patent/GB9605560D0/en active Pending
• 1997
  • 1997-03-17 WO PCT/GB1997/000720 patent/WO1997034470A1/en not_active Ceased
  • 1997-03-17 EP EP97907215A patent/EP0891132A1/de not_active Withdrawn
  • 1997-03-17 AU AU19356/97A patent/AU1935697A/en not_active Abandoned

Non-Patent Citations (1)

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