P.J. PRAUSE DUROTEC GMBH - Federtechnologie mit Faserverbundwerkstoffen


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S-Ply® is the registered name for composite leaf springs that are manufactured by Prause Durotec. The reinforcing material has a strictly parallel-oriented, non-interlaced glass or carbon fibre structure. The fibres are neither pre-stretched nor bent. In contrast to metallic materials with an isotropic structure, they are direction dependent and therefore can be aligned to suit the material structure.   Epoxy resin compounds are used as binding agents. Their special balanced composition ensures high adhesion to the glass fibre surface, resulting in optimum dynamic and electrical properties. The ratio of matrix resin and reinforcement fibres has been chosen to profit from all of the benefits offered by the raw materials selected to form the composite material.   The matrix fulfils a number of important tasks. It provides fixing for the fibre in the desired arrangement and supports it against buckling when under compressive stress.  In addition, it has good load carrying and transmissio


The laminated epoxy-fiberglass material Scotchply™, developed and patented in 1954 by the 3M company, has been processed by Prause Durotec into high performance leaf springs since 1974. Today, using the same improved fibre reinforced composite material, Prause Durotec processes and distributes composite leaf springs under the protected and registered product name S-Ply®.


Substitution of steel spring by S-Ply® leaf spring   Due to their  greater spring action, steel spring packages can be replaced by fewer or even one S-Ply® leaf spring for many applications.   Example:   a) Substitution   b) Cost calculation   Steel leaf spring: 155 x 25 x 2 mm 1 package of 10 springs   S-Ply® leaf spring: It is essential:   with: hS-Ply = Thickness of S-Ply® spring hStahl = Thickness of steel spring nStahl = Amount of steel springs EStahl = Modulus of elasticity (here 210.000 N/mm2) ES-Ply = Modulus of elasticity of S-Ply® leaf spring (here 28.000 N/mm2)   The result is that 10 steel leaf springs with a thickness of 2 mm each can be replaced by only 1 S-Ply® leaf spring with the thickness of 8,5 mm. Steel leaf spring* 10 pieces at 1,20 € = 12,00 € Intermediate package layers 18 pieces at 0,12 € = 2,16 € Total costs 14,16 € * purchase quantity > 1000 pieces, status 2009   S-Ply® leaf spring** 1 pc. at 4,13 € = 4,13 € shim plates (if applicable) 4 pc. at 0,12 € = 0,48


It is possible to have square as well as round shapes, drilled holes and slots from Ø2 – Ø30 mm, with counter bores and tapped holes. To reduce stress concentration and shearing stress when mounting, we recommend the reinforcement of the clamping areas by fixing glass reinforced laminate (GHGW) plates. GHGW-reinforcement plates can be purchased loose or attached to the leaf spring. A special two-component adhesive is applied for the bonding. Following images indicate possible spring shapes:

In 1974, Paul Joachim Prause founded the company Schichtstofftechnik Prause, which was renamed the P. J. Prause Durotec GmbH in 1998. P. J. Prause had previously, as part of 3M Germany, significantly contributed to shaping the technical application of synthetic leaf springs in Germany with Scotchply™ glass-fibre composites. This enabled Prause Durotec GmbH to acquire more than 35 years of experience in the manufacture and application of leaf springs made from fibre composites. Prause Durotec is a medium-sized company with 16 members of staff and a global customer base. The range of products we manufacture includes all configurations of flat leaf springs with E-glass, S-glass, carbon fibres, with epoxy resin providing the matrix. The procedures used to process the UD prepregs (UD = unidirectional) comply with aeronautical and military standards.


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Dieselstraße 14

59823 Arnsberg - Germany


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  • Company headcount
    11 – 50


  • Main activity
    Manufacturer/ Producer

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  • Leaf springs
  • flat springs
  • Carbon products
  • Fibre composite materials
  • reinforced fibreglass
  • Carbon fibre components
  • glass-fibre filled
  • Machine components made from carbon-fibre-reinforced plastic
  • Carbon-fibre-reinforced plastics (CFRP)
  • Leaf springs made from glass-fibre-reinforced plastic (GRP)