FI130845B1

FI130845B1 - Pultrusion apparatus and method for continuous production of non-linear article

Info

Publication number: FI130845B1
Application number: FI20235447A
Authority: FI
Inventors: Ilkka Eskelinen; Timo Laitiainen
Original assignee: Royalcom Oy
Priority date: 2023-04-21
Filing date: 2023-04-21
Publication date: 2024-04-22
Also published as: FI20235447A1

Abstract

A pultrusion apparatus (100) and method for continuous production of a non-linear article (130b). The pultrusion apparatus (100) comprises a stationary heatable die (160), a puller (180) to continuously pull resin-impregnated reinforcement material (130a) through the heatable die (160), wherein the heatable die (160) is configured to arrange the resin-impregnated reinforcement material (130a) into a non-linear shape, a heating arrangement to heat the heatable die (160) to cure the resin-impregnated reinforcement material (130a) being pulled through the heatable die (160) such that the resin-impregnated material (130a) is hardened inside the heatable die (160) to the non-linear shape to form the non-linear article (130b), and a rotatable center roll (170), positioned downstream of the heatable die (160), configured to support the cured non-linear article (130b) which is pulled from the heatable die (160).

Description

PULTRUSION APPARATUS AND METHOD FOR CONTINUOUS PRODUCTION OF

NON-LINEAR ARTICLE

TECHNICAL FIELD

The present disclosure generally relates to pultrusion. The disclosure relates particularly, though not exclusively, to producing non-linear articles by pultrusion.

BACKGROUND

This section illustrates useful background information without admission of any technique described herein representative of the state of the art.

Different types of springs, such as helical coil springs and leaf springs, exist for various — purposes and applications. The springs are often made of hardened steel but other metals and even plastics can be used. Coil springs are typically manufactured by a process of winding, heat treating, grinding, coating, and finishing of metal wires. Leaf springs can be prepared by, for instance, hot rolling or cutting and stamping.

Manufacturing of springs from composite materials can provide significant advantages especially in terms of reduced weight and improved durability compared to the metal springs. Composite springs are typically manufactured by compression molding. However, a need exists for more efficient and continuous manufacturing of composite springs.

SUMMARY

JN The present disclosure aims to improve the process of producing non-linear composite

S 20 articles, such as coil springs and leaf springs. The embodiments of the present disclosure < enable producing non-linear articles, particularly coil springs and leaf springs that have

O

- different cross-sections, radius of curvature, and pitch angle, by pultrusion.

N

E The appended claims define the scope of protection. Any examples and technical

N descriptions of apparatuses, products and/or methods in the description and/or drawings = 25 not covered by the claims are presented not as embodiments of the invention but as 0

N background art or examples useful for understanding the invention.

N

According to a first example aspect there is provided a pultrusion apparatus for continuous production of a non-linear article, comprising a stationary heatable die; a puller to continuously pull resin-impregnated reinforcement material through the stationary heatable die, wherein the heatable die is configured to arrange the resin-impregnated reinforcement material into a non-linear shape; a heating arrangement to heat the heatable die to cure the resin-impregnated material being pulled through the heatable die such that the resin- impregnated material is hardened inside the heatable die to the non-linear shape to form the non-linear article; and a rotatable (rotating) center roll, positioned downstream of the heatable die, configured to support the cured non-linear article which is pulled from the — heatable die.

In certain embodiments, the center roll is configured to assist the puller to pull the cured non-linear article from the heatable die.

In certain embodiments, the pultrusion apparatus comprises a source of reinforcement material and a source of resin. In certain embodiments, the pultrusion apparatus comprises an impregnation arrangement to impregnate the reinforcement material with the resin.

Advantageously, the resin-impregnated reinforcement material may be hardened to its final shape inside the heatable die by simple heating. Further, the length of the non-linear article, i.e., final product, may be freely selected and adjusted after the pultrusion of the continuous non-linear article by cutting.

The non-linear article may also be referred to as a curved article. In certain embodiments, the non-linear article has a cross-sectional shape and size defined by the heatable die. In certain embodiments, the non-linear article has a radius of curvature defined by the heatable die. In certain embodiments, the non-linear article has a pitch angle defined by the & heatable die. In certain embodiments, the non-linear article has a coil diameter defined by a 25 — the heatable die. <Q

N In certain embodiments, the non-linear article has a solid cross-section. In certain = embodiments, the non-linear article has a hollow cross-section. In certain embodiments, the - cross-section is circular. In certain embodiments, the cross-section is rectangular. In certain > embodiments, the cross-section is polygonal. In certain embodiments, the cross-section & 30 comprises both straight and curved edges. In certain embodiments, the cross-section is

N non-symmetrical. In certain embodiments, the cross-section is symmetrical.

Advantageously, an article with a cross-sectional profile best matching the desired properties and application may be produced.

In certain embodiments, the inner surface of the heatable die which determines the non- linear shape of the impregnated reinforcement material is fixed. That is the heatable die comprises no moving parts that are in contact with the resin-impregnated reinforcement material passing through the heatable die. In certain embodiments, the heatable die comprises no moving parts. Advantageously, risk of malfunctioning or breaking of the heatable die may be minimized.

In certain embodiments, the reinforcement material is impregnated with the resin before entering the heatable die. Advantageously, proper mixing of the reinforcement material and resin may be confirmed.

In certain embodiments, the pultrusion apparatus comprises only one heatable die. In certain embodiments, heating is applied only inside the heatable die. Advantageously, the pultrusion apparatus may be kept simple as the heating is performed in one step inside the — heatable die. Further advantageously, a pre-heating device or a pre-heating die is omitted (i.e., the pultrusion apparatus for continuous production of a non-linear article is implemented without a pre-heating device and without a pre-heating die).

In certain embodiments, the resin is a thermosetting resin. In certain embodiments, the resin is an epoxy type resin. In certain embodiments, the resin is a polyester resin. In certain embodiments, the resin is a vinyl ester resin. In certain embodiments, the resin is urethane resin. In certain embodiments, the resin is any thermosetting resin, or a combination of such resins, suitable for pultrusion. Therefore, a wide variety of resins may be used to produce the curved article. Advantageously, the reinforcement material may be feasibly impregnated & with a resin in a liquid from and then cured by heating. Further, the non-linear article is not a 25 susceptible to melting after curing. Further, non-linear articles may be effectively cured to ? the final non-linear form by a one-step heating procedure. Still further, mechanically strong

N articles with excellent thermal stability may be produced.

I

=

N In certain embodiments, the resin comprises filler material. In certain embodiments, the filler > material is particulate matter, such as sand, particulate silica, and small hollow spheres of & 30 various materials. Advantageously, the reinforcement characteristics and/or aesthetics of

N the produced articles may be further adjusted. Further, use of fillers may reduce material and production costs.

In certain embodiments, the apparatus further comprises a surface treatment arrangement for coating the surface of the cured non-linear article. Advantageously, the hardened non- linear article may be effectively further processed, such as coated, painted or chrome plated, after pultrusion.

In certain embodiments, the apparatus further comprises a cutting arrangement for cutting the continuously pultruded cured non-linear article to pieces of a predetermined length.

Advantageously, non-linear articles, or final products, of a predetermined or desired length for a desired application may be feasibly produced.

In certain embodiments, the resin-impregnated reinforcement material comprises at least 55 vol% of reinforcement material. In certain embodiments, the resin-impregnated reinforcement material comprises 40-85 vol% of reinforcement material. In certain embodiments, the resin-impregnated reinforcement material comprises 55-85 vol% of reinforcement material. In certain embodiments, the resin-impregnated reinforcement material comprises 60-85 vol% of reinforcement material. In certain embodiments, the resin- impregnated reinforcement material comprises 65-85 vol% of reinforcement material. In certain embodiments, the resin-impregnated reinforcement material comprises 75-85 vol% of reinforcement material.

In certain embodiments, the reinforcement material is fibrous. In certain embodiments, the reinforcement material comprises synthetic fibers. In certain embodiments, the reinforcement material comprises carbon fibers. In certain embodiments, the reinforcement material comprises lignin-based carbon fibers. In certain embodiments, the reinforcement material comprises other bio-based carbon fibers. In certain embodiments, the reinforcement material comprises recycled carbon fibers. In certain embodiments, the e reinforcement material comprises glass fibers. In certain embodiments, the reinforcement

S 25 material comprises aromatic polyamide (aramid) fibers. In certain embodiments, the <+ reinforcement material comprises natural fibers, such as hemp fibers, or flax fibers. In ? certain embodiments, the reinforcement material comprises a combination of different

N natural and/or synthetic fibers. In certain embodiments, the reinforcement material

E comprises continuous fibers. In certain embodiments, the reinforcement material comprises = 30 chopped or cut fibers. In certain embodiments, the reinforcement material comprises a 5 combination of continuous and sectioned fibers. Advantageously, a broad variety of

O reinforcement material may be used. Further, the physicochemical properties of non-linear articles may be tuned through selection of the reinforcement material.

In certain embodiments, the reinforcement material fibers are straight. In certain embodiments, individual reinforcement material fibers are used. In certain embodiments, the reinforcement material fibers are bundled. In certain embodiments, the reinforcement material fibers are left-handedly or right-handedly twisted. In certain embodiments, the 5 reinforcement material fibers are braided. In certain embodiments, the reinforcement material fibers are weaved. In certain embodiments, the reinforcement material fibers comprise a mixture of sections of straight, twisted, braided and/or weaved fibers.

Advantageously, the mechanical characteristics of non-linear articles may be adjusted by differently aligning the reinforcement material. — In certain embodiments, the cured curved article has a glass transition temperature (Ty) of 40-350 °C. In certain embodiments, the cured curved article has a glass transition temperature (Tg) of 300-350 °C. In certain embodiments, the cured curved article has a Tg of 40-120 °C. In certain embodiments, the cured curved article has a Tg of 80-150 °C. In certain embodiments, the cured curved article has a Tg of 150-250 °C. In certain embodiments, the cured curved article has a Tg of 250-350 °C. In certain embodiments, the cured curved article has a Tg above 350 °C. Advantageously, non-linear articles enduring different thermal conditions for various purposes and fields may be produced.

In certain embodiments, the rotating center roll is coaxial with the heatable die and parallel to the pultrusion processing direction through the heatable die. Advantageously, the non- linear article may be readily transferred from the die onto the rotating center roll. In certain embodiments, the center roll supports the non-linear article pulled from the heatable die. In certain embodiments, the radius (and outer surface) of the center roll is configured to match with the radius of curvature (and inner surface) of the curved article. In certain embodiments, the center roll has a smooth surface. In certain embodiments, the non-linear article is @ 25 collected from the heatable die onto the center roll. In certain embodiments, the rotating < speed of the center roll is configured to match the rotation of the pultruded non-linear article. 3 In certain embodiments, the center roll assists the puller to pull the non-linear curved article . from the heatable die. Advantageously, the pultruded curved article, particularly curved

I articles having pitch angle above zero, may be easily collected and supported by the center > 30 roll as they emerge from the heatable die. In other words, the rotating center roll may be 3 advantageously positioned to pull and support the pultruded non-linear article in the

Q direction of the pultrusion. &

In certain embodiments, the apparatus is configured to actuate rotating movement of (or configured to drive) the center roll from upstream of the heatable die. In certain embodiments, the apparatus comprises an actuating beam passing through the heatable die.

In certain embodiments, the apparatus comprises an actuating beam configured to rotate the center roll, wherein the second end of the actuating beam is connected to a first end of the center roll and the actuating beam is coaxial with the center roll and passes through the heatable die. The actuating beam is not in contact with the resin-impregnated reinforcement material or interact in any way with the resin-impregnated reinforcement material inside the heatable die. That is, the center roll does not participate in shaping the resin-impregnated reinforcement material. In certain embodiments, an actuator for actuating the center roll, by rotating the actuating beam, is positioned upstream of the heatable die and connected to a first end of the actuating beam. Advantageously, the actuator is not located in the way of a pultruded non-linear article. That is, the length of the non-linear article, or the center roll, downstream of the heatable die is not limited by the position of the actuator.

In certain embodiments, the heatable die is configured to arrange the resin-impregnated reinforcement material into a coil spring. Advantageously, a continuous coil spring may be pultruded which may then be cut to final coil spring products of desired lengths. In certain embodiments, the coil spring has a cross-sectional diameter of 1.0 mm — 100 mm. That is, the “wire” or body forming the coil spring is 1.0 mm — 100 mm thick. In certain embodiments, the cross-sectional shape of a coil spring body, i.e. the cross-section of the “wire” forming the coil spring, has a diameter of at least 1.0 mm at its narrowest point. In certain embodiments, the cross-sectional shape of a coil spring body has a diameter of 100 mm or below at its widest point. In certain embodiments, the coil spring has an outer coil diameter of at least 5 mm. In certain embodiments, the coil spring has a pitch angle of 0.1 - 89.9 degrees. Advantageously, non-linear articles having non-zero pitch angle, such as coil @ 25 springs, with a broad range of dimensions and cross-sectional shapes may be effectively < continuously pultruded.

S

- In certain embodiments, the center roll is perpendicular the pultrusion processing direction

N through the heatable die. Advantageously, non-linear articles having the pitch angle of zero

E degrees may be readily supported by the center roll as the articles are pulled from the = 30 — heatable die. Further, the center roll may readily participate in pulling and collecting of 3 curved articles having radius of curvature larger than the radius of the center roll. &

In certain embodiments, the position of the center roll is adjustable. In certain embodiments, the center roll is configured to be switched from the orientation parallel to the heatable die and the drive direction of the pultrusion apparatus to the orientation perpendicular to the axis of the die and the drive direction of the pultrusion apparatus. Advantageously, the position of the center roll may be suitably adjusted according to the dimensions of the curved article to be produced. In certain embodiments, the center roll may be replaced with another center roll having a different diameter to match the dimensions of different-sized curved article to be produced.

In certain embodiments, the heatable die is configured to arrange the resin-impregnated reinforcement material into a leaf spring. In certain embodiments, the non-linear article has a radius of curvature is at least 1.0 mm. In certain embodiments, the radius of curvature is — selected from the range from 1.0 mm to infinity (i.e. straight article with no curvature). In certain embodiments, the leaf spring has a cross-sectional shape of a rectangle, triangle, ellipse, circle, or semi-circle. However, other shapes are possible as well. In certain embodiments, the leaf spring comprises rounded ends having a predetermined radius of curvature. Advantageously, curved articles having zero pitch angle with a broad range of different curvatures and cross-sectional shapes may be pultruded.

According to a second example aspect there is provided a method for continuous production of a non-linear article by pultrusion, the method comprising providing resin-impregnated reinforcement material; continuously pulling the resin-impregnated reinforcement material through a stationary heatable die, wherein the heatable die is configured to arrange the — resin-impregnated reinforcement material into a non-linear shape defined by the heatable die; curing the the resin-impregnated reinforcement material inside the heatable die by heating such that the resin-impregnated reinforcement material is hardened to retain the non-linear shape to form the non-linear article; and supporting the hardened non-linear article, which is being continuously pulled from the heatable die, by a rotating center roll.

O

S 25 In certain embodiments, pulling the curved article is performed by a puller together with the <+ center roll. <Q

N The embodiments presented above with respect to the apparatus of the first example aspect

E are egually applicable to the method of the second example aspect, and vice versa. The

N method of the second example aspect may be implemented in the apparatus of the first 5 30 example aspect.

S

N In certain embodiments, the method further comprises coating the surface of the hardened curved article by a surface treatment arrangement.

In certain embodiments, the method further comprises cutting the hardened non-linear article to pieces of a predetermined length.

In certain embodiments, the method comprises impregnating the reinforcement material with the resin such that the resin-impregnated reinforcement material comprises at least 55 vol% of reinforcement material. In certain embodiments, the method comprises impregnating the reinforcement material with the resin such that the resin-impregnated reinforcement material comprises 40-85 vol% of reinforcement material. In certain embodiments, the resin-impregnated reinforcement material comprises 55-85 vol% of reinforcement material. In certain embodiments, the resin-impregnated reinforcement — material comprises 60-85 vol% of reinforcement material. In certain embodiments, the resin- impregnated reinforcement material comprises 65-85 vol% of reinforcement material. In certain embodiments, the resin-impregnated reinforcement material comprises 75-85 vol% of reinforcement material.

In certain embodiments, the cured non-linear article has a glass transition temperature of 40-350 °C. In certain embodiments, the cured curved article has a glass transition temperature (Tg) of 300-350 °C. In certain embodiments, the cured curved article has a Tg of 40-120 °C. In certain embodiments, the cured curved article has a Tg of 80-150 °C. In certain embodiments, the cured curved article has a Tg of 150-250 °C. In certain embodiments, the cured curved article has a Tg of 250-350 °C. In certain embodiments, the cured curved article has a Tg above 350 °C. Advantageously, non-linear articles enduring different thermal conditions for various purposes and fields enduring high temperatures may be produced.

In certain embodiments, the reinforcement material comprises glass fibers, carbon fibers, e ligning-based carbon fibers, other bio-based carbon fibers, recycled carbon fibers, aromatic

S 25 polyamide fibers, or natural fibers, or a combination thereof. +

S In certain embodiments, the center roll is coaxial with the die and parallel to the drive

N direction through the die. In certain embodiments, the center roll comprises an actuating

E beam which passes through the die and is coaxial with the die. In certain embodiments, the

N method comprises providing an actuator for actuating the center roll, via the actuating beam, 5 30 upstream of the die.

S

N In certain embodiments, the die is configured to arrange the resin-impregnated reinforcement material into a coil spring. In certain embodiments, the coil spring body has a cross-sectional diameter of 1.0 mm - 100 mm. In certain embodiments, the coil spring has an outer coil diameter of at least 5 mm. In certain embodiments, the coil spring has a pitch angle of 0.1 - 89.9 degrees.

In certain embodiments, the center roll is perpendicular to the axis of the die and the drive direction through the die.

In certain embodiments, the heatable die is configured to produce a leaf spring. In certain embodiments, the leaf spring has a radius of curvature of at least 1 mm. The cross-sectional shape and dimensions are defined by the heatable die. In certain embodiments, the leaf spring has a cross-sectional shape of a rectangle, triangle, ellipse, circle, or semi-circle.

However, other shapes are possible as well. In certain embodiments, the leaf spring comprises rounded ends having a predetermined radius of curvature.

According to a third example aspect there is provided a non-linear article manufactured by the method of the second example aspect.

In certain embodiments, the non-linear article is a coil spring or a leaf spring.

In certain embodiments, resin-impregnated reinforcement material of the non-linear article comprises at least 55 vol%, preferably 60-85 vol%, of reinforcement material.

Different non-binding example aspects and embodiments have been illustrated in the foregoing. The embodiments in the foregoing are used merely to explain selected aspects or steps that may be utilized in different implementations. Some embodiments may be presented only with reference to certain example aspects. It should be appreciated that corresponding embodiments may apply to other example aspects as well.

N

< BRIEF DESCRIPTION OF THE FIGURES x = Some example embodiments will be described with reference to the accompanying figures,

N in which: = > 25 Fig. 1 schematically shows a pultrusion apparatus according to certain example

N

> embodiments; & Fig. 2 schematically shows a pultrusion apparatus according to certain further

N embodiments; and

Fig. 3 shows a flow chart according to certain example embodiments.

DETAILED DESCRIPTION

In the following description, like reference signs denote like elements or steps.

The embodiments described in more detail below describe a pultrusion apparatus and method for continuous production of curved, i.e., non-linear, articles, such as coil springs and leaf springs. Note that the embodiments described with respect to the apparatus are equally applicable to the method, and vice versa.

Pultrusion in general is a continuous process used to produce fiber-reinforced composite articles with a constant cross-sectional profile. It is an ideal process for the manufacturing of, for example, either solid or hollow profile flat bars, channels, pipes, tubing, and rods. In a typical pultrusion process, a fiber-reinforced resin material is pulled (hence pultrusion) through a stationary die and hardened to a linear article having the cross-section defined by the die.

The pultrusion apparatus as described in the embodiments below comprises a pultrusion apparatus 100 for continuous production of a non-linear article 130b, comprising a stationary heatable die 160; a puller 180 to continuously pull resin-impregnated reinforcement material 130a through the heatable die 160, wherein the heatable die 160 is configured to arrange the resin-impregnated reinforcement material 130a into a non-linear shape; a heating arrangement to heat the heatable die 160 to cure the resin-impregnated material 130a being pulled through the heatable die 160 such that the resin-impregnated material 130a is hardened inside the heatable die 160 to the non-linear shape to form the non-linear article 130b; and a rotatable center roll 170, positioned downstream of the heatable die 160, configured to support the cured non-linear article 130b which is pulled from the die. In certain embodiments, the center roll 170 is further configured to assist puller & 180 to pull the curved article 130b from the heatable die 160.

N

S 25 The non-linear article 130b may also be referred to as a curved article. The non-linear article

N has a cross-sectional shape and size defined by the heatable die 160. The non-linear article = 130b has a radius of curvature defined by the heatable die 160. The non-linear article 130b - has a pitch angle defined by the heatable die 160. The non-linear article 130b has a coil > diameter defined by the heatable die 160. The non-linear article 130b may be, for instance, & 30 acaoil spring or a leaf spring.

N

Fig. 1 schematically shows a pultrusion apparatus according to certain example embodiments. The pultrusion apparatus 100 according to certain embodiments as shown in Fig. 1 is configured to produce a coil spring. The non-linear article (coil spring) 130b is a composite comprising reinforcement material 120a and resin 120b. The resin 120b may comprise a filler material. First, the reinforcement material 120a is impregnated with the resin 120b in an impregnation tank 150 to produce resin-impregnated reinforcement material 130a. Thereafter, the resin-impregnated reinforcement material 130a is pulled through a heatable die 160. The heatable die 160 is configured to arrange the resin- impregnated reinforcement material 130a, upon being pulled through the die 160, into a desired non-linear shape, such as the coil spring in Fig. 1. By heating the heatable die 160, the resin-impregnated reinforcement material 130a is cured inside the heatable die 160 to retain the non-linear shape (here coil spring) That is, the resin-impregnated reinforcement material 130a, pulled through the heatable die 160, is cured to its final shape inside the heatable die 160 to form a hardened non-linear article 130b. Therefore, hardened nonlinear article 130b may be continuously pulled from the heatable die 160. The non-linear article 130b may not be re-shaped or re-molded after leaving the heatable die 160. That is, the final shape of the non-linear article 130b is determined and achieved inside the heatable die 160.

The reinforcement material 120a is provided from a reinforcement material source 110. The reinforcement material source 110 may be, for instance, a spool. In certain embodiments, the pultrusion apparatus 100 comprises several reinforcement material sources 110. Three reinforcement material sources 110 are shown in Fig. 1 but other number of sources are possible too. Further, an alignment device (not shown) may be used to align the reinforcement material 120a being pulled from the reinforcement material source 110 to achieve a desired relative orientation of the reinforcement material fibers 120a.

The reinforcement material 120a is fibrous material. The reinforcement material 120a may @ 25 be selected, for example, according to its physicochemical properties, processing < characteristics, affordability, and/or the desired application or mechanical properties of the 3 curved article 130b.

N In certain embodiments, the reinforcement material 120a comprises synthetic fibers. In

E certain embodiments, the reinforcement material 120a comprises carbon fibers. In certain = 30 embodiments, the reinforcement material 120a comprises lignin-based carbon fibers. In 5 certain embodiments, the reinforcement material 120a comprises other bio-based carbon

O fibers. In certain embodiments, the reinforcement material 120a comprises recycled carbon fibers. In certain embodiments, the reinforcement material 120a comprises glass fibers. In certain embodiments, the reinforcement material 120a comprises aromatic polyamide

(aramid) fibers. In certain embodiments, the reinforcement material 120a comprises natural fibers, such as hemp fibers, or flax fibers. In certain embodiments, the reinforcement material 120a comprises a combination of different natural and/or synthetic fibers. The skilled person appreciates that the reinforcement material 120a is not limited to the above examples, but other suitable fibers or combinations of fibers may be used too.

The fibers of the reinforcement material 120a may be aligned in different ways to improve and tune the mechanical characteristics of the composites. Generally, reinforcement fibers provide additional mechanical support and fracture resistance. In certain embodiments, the reinforcement material fibers 120a are straight. In certain embodiments, individual reinforcement material fibers 120a are used. In certain embodiments, the reinforcement material fibers 120a are bundled. In certain embodiments, the reinforcement material fibers 120a are left-handedly or right-handedly twisted. In certain embodiments, the reinforcement material fibers 120a are braided. In certain embodiments, the reinforcement material fibers 120a are weaved. In certain embodiments, the reinforcement material fibers 120a comprise a mixture of sections of straight, twisted, braided and/or weaved fibers. Different relative alignments of the reinforcement fibers 120 may be used to achieve different mechanical characteristics.

Furthermore, reinforcement material fibers 120a of different lengths may be used to tune the mechanical properties and processibility. In certain embodiments, the reinforcement material 120a comprises continuous fibers. In certain embodiments, the reinforcement material 120a comprises sectioned, e.g., chopped or cut fibers. In certain embodiments, the reinforcement material 120a comprises a combination of continuous and sectioned fibers.

In certain embodiments, resin 120b is a thermosetting resin. That is, upon curing by heating e the resin 120b is irreversibly hardened. Advantageously, pre-heating or pre-molding

S 25 treatment of the resin 120b or resin-impregnated reinforcement material 130a is not <+ reguired. Further, the curved article is hardened to the final shape in a single heating step. ? In certain embodiments, the resin-impregnated reinforcement material 130a is at ambient

N temperature before entering the heatable die 160. Pre-heating may not even be suitable for

E thermosetting resins as undesired premature hardening could occur. Thanks to = 30 thermosetting resin(s), non-linear article 130b with high thermal stability, rigidity, and creep 5 resistance may be achieved. By combining a thermosetting resin 120b with reinforcement

O material 120a into a resin-impregnated reinforcement material 130a, composites with improved and adjusted mechanical properties may be achieved.

In certain embodiments, the final non-linear curved article 130b has a glass transition temperature (Tg) of 40-350 °C. The Tg properties are related to the used materials, i.e., reinforcement material and resin. In certain embodiments, the cured curved article has a Tg of 300-350 °C. In certain embodiments, the cured curved article has a Tg of 40-120 °C.

Such Tg is suitable, for example, for sports equipment. In certain embodiments, the cured curved article has a Tg of 80-150 °C. Such Tg may be required, for instance, from components designed to be used in construction. In certain embodiments, the cured curved article has a Tg of 150-250 °C. Such Tg may be required, for example, from articles meant to be used in aeronautics. In certain embodiments, the cured curved article has a Tg of 250- 350 °C. In certain embodiments, the cured curved article has a Tg above 350 °C. For example, articles designed for space technology purposes may require very high Tg, even beyond 350 °C. Accordingly, curved articles with different Tg characteristics for different applications and industrial fields may be produced. The skilled person appreciates that the desired Tg characteristics are to be selected and materials chosen according to the desired application and use conditions.

In certain embodiments, the resin 120b is an epoxy type resin. In certain embodiments, the resin 120b is a polyester resin. In certain embodiments, the resin 120b is a vinyl ester resin.

In certain embodiments, the resin 120b is urethane resin. A skilled person appreciates that any thermosetting resin 120b, or a combination of such resins 120b, that is suitable for — pultrusion processing may be used. Potential resins 120b may differ from each other, for example, in terms of curing temperature, affinity for particular reinforcement material fibers 120a, mechanical properties, degradability, visual appearance, chemical reactivity, and affordability. Thus, different resins 120b may be best suited and selected for different purposes or applications. @ 25 In certain embodiments, the resin 120b may comprise filler material. The filler material < typically comprises particulate matter, such as sand, particulate silica, or small hollow 3 spheres of various materials. The filler material may be used to adjust the mechanical . properties and/or aesthetics of the produced articles. Furthermore, economic reasons, such

I as reducing material and production costs, may encourage the use of fillers. For example, > 30 by using filler material in the resin 120b, the amount of required reinforcement material 120a 3 may potentially be reduced while still achieving good mechanical properties.

N

I The impregnation step, together with the amount of reinforcement fibers 120a being pulled from the reinforcement material source(s) 110, determines the resin 120a and reinforcement material 120b composition of the resin-impregnated reinforcement material 130a and, thus, the final composition of the hardened curved article 130b.

The reinforcement material 120a is fully impregnated with the resin 120b in the impregnation tank 150 to provide resin-impregnated reinforcement material 130a. In certain embodiments, the impregnation tank 150 is an open impregnation bath, as shown in Figs. 1-2. In certain embodiments, the impregnation tank 150 is a closed impregnation tank. The resin 120b in the impregnation tank 150 typically is in a liquid form. Therefore, the impregnation tank 150 serves as a resin source for the pultrusion process. The resin- impregnated reinforcement material 130a, being pulled from the reinforcement material source(s) 110, is guided to the impregnation tank 150 via a plurality of directing members 140. Thus, the impregnation tank 150, filled with the resin 120b, and the directing members 140 form an impregnation arrangement to impregnate the reinforcement material 120a. The directing members 140 may be, for example, rotating bars suitably positioned to direct and align the reinforcement fibers 120a into and out of the impregnation tank 160 and thereafter towards the heatable die 160.

In the impregnation tank 150, the reinforcement material fibers 120a are immersed in the resin 120b for a predetermined period of time. The impregnation time is adjustable and dependent, for example, on the position of the guiding members 140, size of the impregnation tank 150, and the speed at which the reinforcement material 120a is being — pulled through the resin 120b in the impregnation tank 150, i.e., the pultrusion processing speed. The reinforcement material 1201 is impregnated with the resin 120b before the heatable die 160. That is, the resin-impregnated reinforcement material 130a is formed before the heatable die 160. Therefore, the proper mixing of the reinforcement material 120a and resin 120b may be accurately controlled and monitored prior to pulling the resin- @ 25 impregnated reinforcement material 130a into the heatable die 160. Therefore, the quality < of the resin-impregnated reinforcement material 130a may be ensured before it is shaped 3 into the non-linear shape by the heatable die 160.

N The resin-impregnated reinforcement material 130a comprises the reinforcement material

E fibers 120a and the resin 120b after the reinforcement fibers 120a have been impregnated = 30 with the resin 120b but before the resin-impregnated reinforcement material 130a has been 5 hardened to the curved article 130b. Thus, the resin-impregnated reinforcement material

O 130a is soft, malleable, and not (yet) cured to hold any particular shape. In certain embodiments, the resin-impregnated reinforcement material 130a comprises at least 55 vol% of the reinforcement material 120a. In certain embodiments, the resin-impregnated reinforcement material 130a comprises 40-85 vol% of the reinforcement material 120a. In certain embodiments, the resin-impregnated reinforcement material comprises 55-85 vol% of reinforcement material. In certain embodiments, the resin-impregnated reinforcement material comprises 60-85 vol% of reinforcement material. In certain embodiments, the resin- impregnated reinforcement material comprises 65-85 vol% of reinforcement material. In certain embodiments, the resin-impregnated reinforcement material comprises 75-85 vol% of reinforcement material.

The resin-impregnated reinforcement material 130a is directed and pulled through the stationary heatable die 160. In certain embodiments, the heatable die 160 is made from metallic material. The metallic material may be, for example, stainless steel. In certain embodiments, the inner surface of the heatable die 160, i.e., the surface which is in contact with the resin-impregnated reinforcement material being pulled through the die, is further coated with another material to increase durability. For instance, the material is any suitable material which is more durable than stainless steel. The heatable die 160, particularly its inner surface, is configured to arrange the resin-impregnated reinforcement material 130a being pulled through the heatable die 160 to a desired shape. In the apparatus 100 depicted in Fig. 1, the desired shape is a coil spring.

The heatable die 160 is stationary. That is, the heatable die 160 does not move during processing. The heatable die 160 comprises no moving parts that are in contact with the — resin-impregnated reinforcement material 130a passing through the heatable die 160. In other words, the inner surface of the heatable die 160 is fixed. In certain embodiments, the heatable die contains no moving parts. Particularly, the inner surface of the heatable die 160 which determines the non-linear shape of the impregnated reinforcement material is fixed. Advantageously, risk of malfunctioning or breaking of the heatable die or parts of the @ 25 — heatable die is minimized. & + The cross-section of the curved article 130b, the coil spring in the embodiments according ? to Fig. 1, is determined by the heatable die 160. In certain embodiments, the coil spring

N body has a cross-sectional diameter of 1.0 mm - 100 mm. In certain embodiments, the

E cross-sectional shape of a coil spring body has a diameter of at least 1.0 mm atits narrowest = 30 point. In certain embodiments, the cross-sectional shape of a coil spring body has a 3 diameter of 100 mm or below at its widest point. &

The coil diameter of the coil spring is determined by the heatable die 160. In certain embodiments, the outer coil diameter is 5 mm. In certain embodiments, the outer coil diameter is at least 5 mm. Therefore, curved articles with a broad range of different curvatures may be produced and the curvature.

The pitch angle of the curved article 130b, the coil spring in the embodiments according to

Fig. 1, is determined by the heatable die 160. In certain embodiments, the coil spring has a pitch angle of 0.1 - 89.9 degrees. In certain embodiments, the pitch angle is zero. In certain embodiments, the pitch angle is at least 0.1 degrees. In certain embodiments, the pitch angle is 10 degrees. In certain embodiments, the pitch angle is 89.9 degrees at maximum.

Therefore, coil springs with different pitch may be manufactured by adjusting the pitch angle.

In certain embodiments, the non-linear article 130b has a solid cross-section. In certain embodiments, the curved article has a hollow cross-section. In certain embodiments, the cross-section is circular. In certain embodiments, the cross-section is rectangular. In certain embodiments, the cross-section is triangular. In certain embodiments, the cross-section is polygonal. In certain embodiments, the cross-section comprises both straight and curved edges. In certain embodiments, the cross-section is non-symmetrical. In certain embodiments, the cross-section is symmetrical.

The resin-impregnated reinforcement material 130a is cured inside the heatable die 160 by heating the heatable die 160 to a curing temperature. The heating hardens the thermosetting resin 120b of the resin-impregnated reinforcement material 130a. That is, the — resin-impregnated reinforcement material 130a is hardened to form a solid non-linear article 130b before exiting the heatable die 160. The continuous curved article 130b retains the shape determined by the heatable die 160 after leaving the heatable die 160. Accordingly, the shape into which the resin-impregnated reinforcement material 130a is shaped and e cured inside the heatable die 160 is the final form of the non-linear article 130b. The curing

S 25 proceeds continuously inside the heatable die 160 as the resin-impregnated reinforcement <+ material 130a is pulled through the heatable die 160. Therefore, solid curved article 130b ? may continuously extend and be pulled from the heatable die 160 as long as reinforcement

N material 120a and resin 120b are available for processing. In certain embodiments, the

E heating is performed by a heater integrated to the heatable die 160. In certain embodiments, 3 30 the heating is performed by an external heater (not shown). 3

N In certain embodiments, the pultrusion apparatus 100 comprises only one heatable die. In

N certain embodiments, the pultrusion apparatus 100 is a single-die apparatus. In certain embodiments, heating is applied only inside the heatable die 160. That is, only one heatable die 160 or a device is enough for the pultrusion apparatus 100. A pre-heating device or a pre-heating die is not needed. Advantageously, the pultrusion apparatus 100 may be kept simple as the curing (heating) is performed only in one part of the pultrusion apparatus 100, i.e., the heatable die 160.

The curing temperature required to harden the resin-impregnated reinforcement material 130a depends on the resin-impregnated reinforcement material 130a and may be adjusted accordingly. The curing temperature may be, for example, 100 °C, 140 °C, or 170 °C, or above 170 °C. Maximum curing temperature is limited by the degradation temperature of the resin 120a and/or reinforcement material 120b. In certain embodiments, a pre-heater — (not shown) is used to stabilize the temperature of the resin-impregnated reinforcement material 130a before it enters the heatable die 160. In certain embodiments, the heatable die 160 comprises a temperature gradient, or regions with different temperatures. For example, the heatable die 160 may comprise three temperature regions with increasing temperature from the die entrance towards the exit. The temperature may be 40-70 °C at the entrance, 80-110 °C in the middle of the die 160, and 140-170 °C at the exit. Thus, the resin-impregnated reinforcement material 130a may be suspected to a gradually increasing temperature as it is pulled through the heatable die 160 to cure the material.

Advantageously, the heating of the resin-impregnated reinforcement material 130a may be accurately controlled.

The cured curved article 130b is continuously collected on a rotating center roll 170 as it emerges from the heatable die 160. The center roll 170 supports the non-linear article emerging from the heatable die 160. The center roll 170 also pulls the curved article 130b from the heatable die 160 together with puller 180. In certain embodiments, the puller 180 is a caterpillar puller. In certain embodiments, the puller 180 is a reciprocating puller. In the @ 25 embodiments according to Fig. 1, the center roll 170 is aligned coaxially to the heatable die < 160 and parallel to the pultrusion processing direction. Particularly, the center roll 170 is 3 coaxial with the coil spring shape determined by the heatable die shown in Fig. 1. In certain . embodiments according to Fig. 1, the center roll 170 is also perpendicular to the axis of the

I puller 180. The center roll 170 has outer diameter and surface arranged to match the inner > 30 surface of the curved article 130b, i.e. coil spring in the case of Fig. 1. In certain s embodiments, the center roll 170 has a smooth surface. In certain embodiments, the center 2 roll has a contoured surface to match the dimensions of the curved article and to further & promote the pulling of the non-linear article 130b from the heatable die 160. In certain embodiments, adjustable guiding member(s) (not shown) may be used to align and settle — the non-linear article 130b onto the center roll 170.

The coil spring 130b of Fig. 1 rotates at a certain speed depending on the pultrusion speed as it emerges from the heatable die 160. The rotating center roll 170 is adjustable to rotate according to the rotating speed of the coil spring 130b being pulled from the heatable die 160. Therefore, the coil spring-shaped curved article 130b becomes collected and may directly proceed along the center roll after the heatable die 160. Due to rotation of the center roll 170, for instance, contact-induced friction may be reduced. At the same time, the rotation of the center roll 170 assists the puller 180 in pulling the curved article 130b from the heatable die 160. The puller 180, in general, is configured to pull the reinforcement material 120a and, after impregnation, the resin-impregnated reinforcement material 130a through — the apparatus 100 to produce the curved article 130b, which is pulled from the heatable die 160 onto the rotating center roll 170.

The center roll 170 is rotated by an actuator 190. The actuator 190 is connected to the center roll 170 via an actuating beam 175. In certain embodiments, the actuator 190 rotates the center roll 170 by rotating the actuating beam 175, as shown in Fig. 1. In certain embodiments, the actuator 190 is electrically driven. In certain embodiments, the actuator 190 is pneumatically driven. In certain embodiments, the actuator 190 is hydraulically driven.

The actuating beam 175 is configured to rotate the center roll 170. In certain embodiments, the actuating beam 175 is coaxial with the center roll 170 and passes through the heatable die 160, as shown in Fig. 1. In certain embodiments, the actuating beam 175 is coaxial with the die 160, and/or the shape determined by the heatable die 160, and parallel to the drive direction passing through the die 160. The second end of the actuating beam 175 is connected to a first end of the center roll 170. The second end of the center roll 170 points away from the heatable die 160 into the processing direction. The first end of the actuating @ 25 beam 175 is connected to the actuator 190. The diameter of the actuating beam 175 is < smaller than the inner diameter of the coil spring shape determined by the heatable die 160. 3 That is, the actuating beam 175 is not in contact with the resin-impregnated reinforcement

ES material 130a inside heatable die 160. Accordingly, the actuating beam 175 is not in contact

I or interact in any way with the resin-impregnated reinforcement material 130a or non-linear > 30 article 130b inside the heatable die 160. That is, the actuating beam 175 does not participate 3 in shaping the resin-impregnated reinforcement material 130a.

N

I In certain embodiments, the actuator 190 is positioned upstream of the heatable die 160 as shown in Fig. 1. This has the advantage that the actuator 190 does not limit the length of the curved article 130b or the center roll 170. Should the actuator be positioned downstream of the heatable die 160 (and the center roll 170), the extending curved article 130b would eventually extend pass the center roll 170 and against the actuator 190, thereby limiting the maximum manufacturing length. Thus, to prepare particularly long curved articles, the actuator 190 would need to be positioned accordingly very far away downstream of the heatable die 160. However, having the actuator upstream of the die, removes any risk or positioning issues where the length of the curved article 130b or the center roll 170, no matter how long, would be limited by the positioning of the actuator 190. This further enables freely adjusting the length of the center roll. Replacing and/or changing the center roll 170 is also made easier.

In certain embodiments, the apparatus 100 further comprises a surface treatment arrangement (not shown in Fig. 1) for coating the surface of the cured curved article 130b.

Therefore, the cured curved article 130b may be further processed, such as coated, painted or chrome plated, rapidly after the pultrusion. Other surface treatment options are possible too.

In certain embodiments, the apparatus 100 further comprises a cutting arrangement (not shown in Fig. 1) for cutting the continuous cured curved article 130b to pieces of a predetermined length. Thereby, the curved articles 130b may be cut to a suitable length for a desired application. That is, the final products of desired length may pre produced from the continuous non-linear article 130b.

Fig. 2 schematically shows a pultrusion apparatus according to certain further embodiments. The pultrusion apparatus 200 as shown in Fig. 2 is configured to produce a curved article with a zero-degree pitch angle, such as a leaf spring 130b. Pitch angle of O degrees implies that if continuing the pultrusion process long enough the non-linear article e 130 would eventually reach the form of a full circle as there is no coil pitch like in a coil

S 25 spring. To produce the leaf spring 130b, the center roll 170 is positioned perpendicular to <+ the pultrusion processing direction downstream of the heatable die 160, such that the ? curved article is pulled between the puller 180 and the center roll 170. Thus, in certain

N embodiments according to Fig. 2, the center roll is parallel to the axis of the puller 180.

E Accordingly, the actuator 190 is positioned to the side of the apparatus 200 in line with the = 30 — centerroll 170 (actuator not shown in Fig. 2) and the actuating beam 175 does not pass 5 through the heatable die 160 nor is it coaxial with the die 160 as shown in Fig. 1. The radius

O of curvature of the center roll 170 is not reguired match the radius of curvature of the non- linear article 130b, but nonetheless supports it and promotes its pulling by rotating.

Otherwise, the pultrusion processing and material principles presented with respect to the embodiments according to Fig. 1 are applicable also to the apparatus 200 of Fig. 2.

To produce a leaf spring 130b, as shown in Fig. 2, the heatable die 160 is configured to arrange the resin-impregnated reinforcement material 130a into the shape of a leaf spring.

That is, the shape has a certain cross-section and radius of curvature, and a pitch angle of

O degrees. The leaf spring 130b emerges from the heatable die 160 in the longitudinal direction. In certain embodiments, the leaf spring has a cross-sectional shape of a rectangle, triangle, ellipse, circle, or semi-circle. However, other shapes are possible as well. In certain embodiments, the leaf spring 130b has a radius of curvature of at least 1 mm. The height, width, and the radius of curvature of the leaf spring 130b may be freely selected by the skilled person. The resin-impregnated reinforcement material 130a is cured, i.e. hardened, to the final leaf spring shape by heating inside the heatable die 160 as the material is continuously pulled through the die 160.

In certain embodiments, the continuous curved article leaf spring 130b pulled from the — heatable die 160 is cut to final leaf spring products of a desired length by a cutting arrangement 220. In certain embodiments, the final leaf spring product comprises rounded ends having a predetermined radius of curvature. In certain embodiments, the apparatus 100 comprises a surface treatment arrangement 210 for coating the surface of the leaf spring 130b.

Inproducing leaf spring 130b, the center roll 170 pulls the leaf spring 130b from the heatable die 160 together with the puller 180. The center roll 170 supports the leaf spring 130b being pulled from the die 160. Unlike when producing coil springs as in Fig. 1, the leaf spring 130b is not closely wrapped around or onto the center roll 170. The rotation of the center roll is e adjusted according to the drive speed of the pultrusion apparatus 100.

N

& + 25 Fig. 3 shows a flow chart according to certain example embodiments. Fig. 3 depicts a

S method for producing a non-linear article by pultrusion. The method may be implemented

N in the apparatus 100, 200 and their embodiments described above in connection to Figs. 1

E and 2.

NM

> The method comprises following steps:

N

N 30 310: providing resin-impregnated reinforcement material 130a. The reinforcement material 120a is fully impregnated with the resin 120b in an impregnation tank 150 to provide resin- impregnated reinforcement material 130a. In certain embodiments, the reinforcement material 102 is impregnated with the resin 120b before the heatable die 160. In certain embodiments, he reinforcement material 120a is fibrous material. In certain embodiments, the reinforcement material 120a comprises synthetic, natural fibers, or combinations thereof. In certain embodiments, the reinforcement material fibers 120a are bundled, twisted, braided, or weaved. In certain embodiments, the resin 120b is a thermosetting resin or a combination of such resins, suitable for pultrusion. In certain embodiments, the resin 120b further comprises filler material, the filler material typically being particulate matter, such as sand or particulate silica. 320: continuously pulling the resin-impregnated reinforcement material 130a through a stationary heatable die 160, wherein the heatable die 160 is configured to arrange the resin- impregnated reinforcement material 130a into a non-linear shape defined by the heatable die 160. The heatable die 160 is stationary. That is, the heatable die 160 does not move during processing. The heatable die 160 comprises no moving parts that are in contact with the resin-impregnated reinforcement material 130a or non-linear article 130b passing — through the heatable die 160. In certain embodiments, the heatable die contains no moving parts. Particularly, the inner surface of the heatable die 160 which determines the non-linear shape of the impregnated reinforcement material is fixed. The heatable die 160 is configured to arrange the resin-impregnated reinforcement material 130a to a non-linear shape, such as coil spring or a leaf spring. A coil spring has a certain cross-section, coil diameter and pitch angle determined by the heatable die 160. A leaf spring has a certain cross-section and radius of curvature determined by the die 160, and a pitch angle of O degrees.

In certain embodiments, the cross-section is rectangular, triangular, elliptical, circular, or semi-circular. However, other shapes are possible too. In certain embodiments, the coil @ 25 diameter of a coil spring is 5 mm at minimum. In certain embodiments, the pitch angle of a < coil spring is 0.1-89.9 degrees. In certain embodiments, the coil spring body, that is, the 3 material forming the spring, is 1.0 - 100 mm thick. In certain embodiments, the coil outer . diameter is at least 5 mm. In certain embodiments the radius of curvature of a leaf spring is

I 1 mm at minimum. a = 30 330: curing the resin-impregnated reinforcement material 130a inside the heatable die 160 5 by heating such that the resin-impregnated reinforcement material 130a is hardened to

O retain the non-linear shape, i.e., the final shape, to form the non-linear article 130b. Re- molding or re-shaping after the heatable die 16 is not needed or possible when using thermosetting resin(s). In certain embodiments, the heating is performed in only one heatable die 160. In certain embodiments, heating is applied only inside the heatable die 160. That is, only one heatable die or a device may be enough for the pultrusion apparatus 100. A pre-heating device or a pre-heating die may not be needed. The curing temperature required to harden the resin-impregnated reinforcement material 130a depends on the resin-impregnated reinforcement material 130a and may be adjusted accordingly. The curing temperature may be, for example, 100 °C, 140 °C, or 170 °C, or above 170 °C.

Maximum curing temperature is limited by the degradation temperature of the resin 120a and/or reinforcement material 120b. In certain embodiments, a pre-heater is used for temperature control and/or to pre-heat the resin-impregnated reinforcement material 130a — before it enters the heatable die 160. Due to heating in the heatable die 160 the resin- impregnated reinforcement material 130a is hardened to a final shape before leaving the heatable die 160. Thus, a solid non-linear article 130b exits the die 160. 340: supporting the hardened non-linear article 130b, which is being continuously pulled from the heatable die 160, by a rotating center roll 170. In certain embodiments, the center — roll 170 assists the puller 180 to pull the curved article 130b from the heatable die 160. In certain embodiments, the curved article 130b is collected onto the center roll 170. The rotation of the center roll 170 is adjusted according to the drive speed of the pultrusion apparatus 100. The diameter of the center roll 170 is adjusted according to the dimensions of the curved article 130b. The rotation of the center roll 170 assists the puller 180 in pulling the curved article 130b from the heatable die 160. In certain embodiments, the curved article 130b is further process by cutting and/or coating after being collected from the heatable die 160. In certain embodiments, the diameter of the center roll is configured to match the inner diameter of the non-linear article 130b. In certain embodiments, the center roll has a smooth surface. @ 25 — Without limiting the scope and interpretation of the patent claims, certain technical effects < of one or more of the example embodiments disclosed herein are listed in the following. A

S technical effect is improved preparation of a non-linear article by pultrusion. Another

N technical effect is manufacturing of coiled objects by pultrusion.

I a Various embodiments have been presented. It should be appreciated that in this document, = 30 words comprise, include, and contain are each used as open-ended expressions with no 3 intended exclusivity. &

The foregoing description has provided by way of non-limiting examples of particular implementations and embodiments a full and informative description of the best mode presently contemplated by the inventors for carrying out the invention. It is however clear to a person skilled in the art that the invention is not restricted to details of the embodiments presented in the foregoing, but that it can be implemented in other embodiments using equivalent means or in different combinations of embodiments without deviating from the characteristics of the invention.

Furthermore, some of the features of the afore-disclosed example embodiments may be used to advantage without the corresponding use of other features. As such, the foregoing description shall be considered as merely illustrative of the principles of the present invention, and not in limitation thereof. Hence, the scope of the invention is only restricted by the appended patent claims.

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Claims

1. A pultrusion apparatus (100) for continuous production of a non-linear article (130b), comprising: a stationary heatable die (160); characterized in that the pultrusion apparatus (100) comprises: a puller (180) to continuously pull resin-impregnated reinforcement material (130a) through the heatable die (160), wherein the heatable die (160) is configured to arrange the resin-impregnated reinforcement material (130a) into a non-linear shape; a heating arrangement to heat the heatable die (160) to cure the resin-impregnated reinforcement material (130a) being pulled through the heatable die (160) such that the resin-impregnated material (130a) is hardened inside the heatable die (160) to the non- linear shape to form the non-linear article (130b); and a rotatable center roll (170), positioned downstream of the heatable die (160), configured to support the cured non-linear article (130b) which is pulled from the heatable — die (160).

2. The apparatus (100) of claim 1, wherein the inner surface of the heatable die (160) is fixed.

3. The apparatus (100) of any preceding claim, wherein the reinforcement material (120a) is impregnated with the resin (120b) before entering the heatable die (160).

4. The apparatus (100) of any preceding claim, comprising only one heatable die (160).

5. The apparatus (100) of any preceding claim, wherein the resin (120b) is a < thermosetting resin. N &

A

6. The apparatus (100) of any preceding claim, further comprising a surface treatment = arrangement (210) for coating the surface of the cured non-linear article (130b). E 25

7. The apparatus (100) of any preceding claim, further comprising a cutting arrangement K (220) for cutting the continuous cured non-linear article (130b) to pieces of a predetermined + = length. 0 S

N

8. The apparatus (100) of any preceding claim, wherein the cured non-linear article (130b) has a glass transition temperature of 40-350 °C.

9. The apparatus (100) of any preceding claim, wherein the rotatable center roll (170) is coaxial with the heatable die (160) and parallel to the pultrusion processing direction through the heatable die (160).

10. The apparatus (100) of claim 9, comprising an actuating beam (175) configured to rotate the center roll (170), wherein the second end of the actuating beam (175) is connected to a first end of the center roll (170) and the actuating beam (175) is coaxial with the center roll (170) and passes through the heatable die (160).

11. The apparatus (100) of claim 10, wherein an actuator (190) for actuating the center roll (170), by rotating the actuating beam (175), is positioned upstream of the heatable die — (160) and connected to a first end of the actuating beam (175).

12. The apparatus (100) of any preceding claim, wherein the heatable die (160) is configured to arrange the resin-impregnated reinforcement material (130a) into a coil spring (130b).

13. The apparatus (100) of any one of the claims 1-8, wherein the center roll (170) is — perpendicular to the pultrusion processing direction through the heatable die (160).

14. The apparatus (100) of claim 13, wherein the heatable die (160) is configured to arrange the resin-impregnated reinforcement material (130a) into a leaf spring (130b).

15. A method for continuous production of a non-linear article (130b) by pultrusion, the method comprising: providing resin-impregnated reinforcement material (130a); characterized by S continuously pulling the resin-impregnated reinforcement material (130a) through a A stationary heatable die (160), wherein the heatable die (160) is configured to arrange the = resin-impregnated reinforcement material (130a) into a non-linear shape; curing the resin-impregnated reinforcement material (130a) inside the heatable die : (160) by heating such that the resin-impregnated reinforcement material (130a) is hardened = to retain the non-linear shape to form the non-linear article (130b); and 5 supporting the hardened non-linear article (130b), which is being continuously pulled O from the heatable die (160), by a rotating center roll (170).