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EP0270707A1 - Bowstring - Google Patents

Bowstring Download PDF

Info

Publication number
EP0270707A1
EP0270707A1 EP86202166A EP86202166A EP0270707A1 EP 0270707 A1 EP0270707 A1 EP 0270707A1 EP 86202166 A EP86202166 A EP 86202166A EP 86202166 A EP86202166 A EP 86202166A EP 0270707 A1 EP0270707 A1 EP 0270707A1
Authority
EP
European Patent Office
Prior art keywords
bowstring
filaments
polyethylene
gpa
kmol
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP86202166A
Other languages
German (de)
French (fr)
Inventor
Hendrikus Matheus Schoffeleers
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Stamicarbon BV
Original Assignee
Stamicarbon BV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to NL8501775A priority Critical patent/NL8501775A/en
Application filed by Stamicarbon BV filed Critical Stamicarbon BV
Priority to EP86202166A priority patent/EP0270707A1/en
Publication of EP0270707A1 publication Critical patent/EP0270707A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • DTEXTILES; PAPER
    • D01NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01FCHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/02Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
    • D01F6/04Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolymers obtained by reactions only involving carbon-to-carbon unsaturated bonds from polyolefins
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F41WEAPONS
    • F41BWEAPONS FOR PROJECTING MISSILES WITHOUT USE OF EXPLOSIVE OR COMBUSTIBLE PROPELLANT CHARGE; WEAPONS NOT OTHERWISE PROVIDED FOR
    • F41B5/00Bows; Crossbows
    • F41B5/14Details of bows; Accessories for arc shooting
    • F41B5/1403Details of bows
    • F41B5/1411Bow-strings

Definitions

  • the invention relates to a bowstring made wholly or mainly of synthetic filaments, whether or not bundled into threads.
  • Synthetic bowstrings are known and are often applied in archery. Examples are bowstrings on the basis of polyesters, such as a polyethylene terephthalate marketed by Du Pont under the name Dacron, and bowstrings on the basis of aromatic polyamides, such as an aramide product marketed by Du Pont under the name Kevlar.
  • the present invention provides a bowstring that, on the one hand, exhibits an extremely low elongation and a very high arrow velocity, while on the other hand, it has an extraordinarily long life.
  • the invention therefore relates to a bowstring comprising a number of synthetic filaments, whether or not bundled into threads, that is characterized in that use is made of filaments having a tensile strength of at least 2 GPa and a modulus of at least 20 GPa on the basis of polyethylene having a weight-average molecular weight of at least 4 x 10 5 kg/Kmol.
  • filaments obtained by converting a solution of linear polyethylene having a weight-average molecular weight of at least 4 x 10 5 kg/Kmol by thermoreversible gelation into a homogeneous polyethylene gel of virtually the same composition as the solution started from, and stretching this gel at a stretch ratio of at least 10.
  • a number of filaments is often bundled into threads, upon which a number of threads is wound into a string, for instance on a string board.
  • the number of threads for the string is determined by the desired drawing force of the bow and generally amounts to 8-20, the number of filaments used generally being 1000-3000, depending on filament thickness.
  • the length of the string is determined by the bow length and is generally chosen to be 5-10 cm smaller than the bow length.
  • the string is in the usual way provided with servings and a middle serving, for instance on a string board, and is often treated with a wax, such as beeswax, to ,keep the threads together.
  • a wax such as beeswax
  • a bowstring on the basis of polyethylene filaments according to the invention was tested on a longbow during some months. After more than 5000 shots the string exhibited no deterioration in strength or increase in elongation, while the original, very high arrow velocity was fully retained.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Textile Engineering (AREA)
  • Stringed Musical Instruments (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Artificial Filaments (AREA)

Abstract

Bowstring comprising filaments having a tensile strength ≧ 2 GPa and a modulus ≧ 20 GPa on the basis of linear polyethylene having an Mw of a 4 × 105 kg/Kmol.
Preferably the filaments are obtained by thermoreversible gelation of a polyethylene solution followed by stretching.
The bowstring obtained shows very low elongation, a high arrow velocity and an extremely long life.

Description

  • The invention relates to a bowstring made wholly or mainly of synthetic filaments, whether or not bundled into threads.
  • Synthetic bowstrings are known and are often applied in archery. Examples are bowstrings on the basis of polyesters, such as a polyethylene terephthalate marketed by Du Pont under the name Dacron, and bowstrings on the basis of aromatic polyamides, such as an aramide product marketed by Du Pont under the name Kevlar.
  • It has been found that bowstrings from Dacron have a long life, but exhibit the disadvantages of a high elongation and low arrow velocity. Bowstrings from Kevlar, on the contrary, are found to break rather quickly, for instance after 1000-1500 shots, while, on the other hand, the elongation still is substantial and the arrow velocity not yet really high.
  • The present invention provides a bowstring that, on the one hand, exhibits an extremely low elongation and a very high arrow velocity, while on the other hand, it has an extraordinarily long life.
  • The invention therefore relates to a bowstring comprising a number of synthetic filaments, whether or not bundled into threads, that is characterized in that use is made of filaments having a tensile strength of at least 2 GPa and a modulus of at least 20 GPa on the basis of polyethylene having a weight-average molecular weight of at least 4 x 105 kg/Kmol.
  • In the present invention use can be made in particular of filaments obtained by converting a solution of linear polyethylene having a weight-average molecular weight of at least 4 x 105 kg/Kmol by thermoreversible gelation into a homogeneous polyethylene gel of virtually the same composition as the solution started from, and stretching this gel at a stretch ratio of at least 10.
  • The preparation of such filaments is disclosed in, for instance, US-A-4,344,908; US-A-4,422,993; US-A-4,430,383; US-A-4,411,854 and US-A-4,436,689.
  • In the present invention a number of filaments is often bundled into threads, upon which a number of threads is wound into a string, for instance on a string board. The number of threads for the string is determined by the desired drawing force of the bow and generally amounts to 8-20, the number of filaments used generally being 1000-3000, depending on filament thickness. The length of the string is determined by the bow length and is generally chosen to be 5-10 cm smaller than the bow length.
  • The string is in the usual way provided with servings and a middle serving, for instance on a string board, and is often treated with a wax, such as beeswax, to ,keep the threads together.
  • Example
  • A bowstring on the basis of polyethylene filaments according to the invention was tested on a longbow during some months. After more than 5000 shots the string exhibited no deterioration in strength or increase in elongation, while the original, very high arrow velocity was fully retained.

Claims (3)

1. Bowstring comprising a number of synthetic filaments, whether or not bundled into threads, characterized in that use is made of filaments having a tensile strength of at least 2 GPa and a modulus of at least 20 GPa on the basis of polyethylene having a weight-average molecular weight of at least 4 X 105 kg/Kmol.
2. Bowstring according to claim 1, characterized in that use is made of polyethylene filaments obtained by converting a solution of a linear polyethylene having a weight-average molecular weight of at least 4 x 105 kg/Kmol by thermoreversible gelation into a homogeneous polyethylene gel of virtually the same composition as the solution started from and stretching this gel at a stretch ratio of at least 10.
3. Bowstring substantially as described.
EP86202166A 1985-06-20 1986-12-04 Bowstring Withdrawn EP0270707A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
NL8501775A NL8501775A (en) 1985-06-20 1985-06-20 Bowstring formed from polyethylene filaments - with high tensile strength and modulus
EP86202166A EP0270707A1 (en) 1986-12-04 1986-12-04 Bowstring

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP86202166A EP0270707A1 (en) 1986-12-04 1986-12-04 Bowstring

Publications (1)

Publication Number Publication Date
EP0270707A1 true EP0270707A1 (en) 1988-06-15

Family

ID=8195828

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86202166A Withdrawn EP0270707A1 (en) 1985-06-20 1986-12-04 Bowstring

Country Status (1)

Country Link
EP (1) EP0270707A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5749214A (en) * 1996-10-04 1998-05-12 Cook; Roger B. Braided or twisted line

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2051667A (en) * 1979-06-27 1981-01-21 Stamicarbon Preparing polyethylene filaments
EP0055001A1 (en) * 1980-12-23 1982-06-30 Stamicarbon B.V. Filaments with high tensile strength and modulus and process for the production thereof
EP0077590A1 (en) * 1981-10-17 1983-04-27 Dsm N.V. Process for the production of polymer filaments having high tensile strength and modulus
NL8501775A (en) * 1985-06-20 1987-01-16 Stamicarbon Bowstring formed from polyethylene filaments - with high tensile strength and modulus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2051667A (en) * 1979-06-27 1981-01-21 Stamicarbon Preparing polyethylene filaments
EP0055001A1 (en) * 1980-12-23 1982-06-30 Stamicarbon B.V. Filaments with high tensile strength and modulus and process for the production thereof
EP0077590A1 (en) * 1981-10-17 1983-04-27 Dsm N.V. Process for the production of polymer filaments having high tensile strength and modulus
NL8501775A (en) * 1985-06-20 1987-01-16 Stamicarbon Bowstring formed from polyethylene filaments - with high tensile strength and modulus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
25. INTERNATIONALE CHEMIEFASERTAGUNG, Dornbirn, 24th-26th September 1986, pages 1-35, AT; R, KIRSCHBAUM et al.: "High strength/high modulus polyethylene fibers" *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5749214A (en) * 1996-10-04 1998-05-12 Cook; Roger B. Braided or twisted line

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Legal Events

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PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

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AK Designated contracting states

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Designated state(s): AT BE CH DE ES FR GB IT LI LU NL SE

STAA Information on the status of an ep patent application or granted ep patent

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18D Application deemed to be withdrawn

Effective date: 19881216

RIN1 Information on inventor provided before grant (corrected)

Inventor name: SCHOFFELEERS, HENDRIKUS MATHEUS