DE3048367C1 - Method and device for spreading a fiber strand - Google Patents

Description

The invention relates to a method and a device for spreading a fiber running in alignment strangs, which consists of single juxtaposed parallel fibers consists of a machine element with convex Surface penetrates into the fiber strand and this if possible diversified.

From "Kunststoffe" Volume 58, 1967, Issue 6, pages 447-455 "Problems with impregnation and drawing of fiber optic strands" it is known to pass a strand of fiber before going through it Spreading the drawing nozzle by means of flex rollers, so that an intimate Rolling in of the resin is effected. This reference however, gives no indication of the preparation of a fiber strangs for the production of winding bodies in thin layers technology.

Fiber materials are used to manufacture fiber structures processed according to the pre-preg technique or the wet technique.  

With wet technology, a fiber strand is evenly in Resin soaked and wound on a base. At With this technique the structure density and fiber content of the Depending on the geometry of the fiber strand. Because a strand of fiber very many individual fibers and mostly the fiber strand unevenly from the so-called thread eye of a machine expires, can be achieved with previous winding methods a homogeneous and stable structure Layers necessary. Due to the large number of layers required the wall thickness of the structure results and with that also affects the economy.

Particularly in the case of carbon fiber structures in which the Fiber price is high, it is therefore necessary to manufacture to develop methods with optimally low fiber provide the highest quality to economically fiber to produce bobbins.

Thin film technology is one such method. Doing so the structure of thin fiber layers with a high fiber content constructed very homogeneously and therefore even with smaller ones Wall thicknesses than in conventional winding processes desired stability achieved.

The object of the invention is particularly concerned with the manufacture of carbon fiber tubes for use in gas ultracentrifuges. The technique described below  can also be used for electric motors, genera gates or other high-speed machines are used, where rotationally symmetrical fiber packages with low Imbalance distribution and high structural strength required will.

The object of the invention is a carbon fiber strand after passing through the drinking bath in a wider range Spread flat with constant thickness.

This object is achieved in that a saturated carbon fiber strand by penetration of a convex in the longitudinal and transverse fiber directions machine element is spread. The machine element can be a sphere or a spherical cap.

The fiber strand is arranged by a suitable arrangement of Guide roller and a subsequent ball surface brought the desired bandwidth and with the help of a spring-loaded storage roll with adjustable feed deposited on the surface of the mandrel. Through this Measure remains the bandwidth reached by the ball preserved during and after filing, making it very thin Layers with high fiber content as well as an even one Impregnation of the fiber strand largely independent of the winding speed and tension of the fiber strand can be achieved.

The invention is illustrated below with the aid of an embodiment explained in more detail.  

The only figure shows a cross section through an invented Storage device according to the invention for producing thin-walled, rotationally symmetrical fiber winding body made of impregnated Carbon fibers.

In a housing, of which only a wall 2 can be seen in the cross-sectional view of FIG. 1, a thread inlet roller 4 , an intermediate roller 6 , a further intermediate roller 8 , a guide roller 10 , an adjustable feed 11 and a thread outlet roller 12 are mounted or attached. The housing with the components mentioned is pivotable about an axis AA , which is formed by a bolt 14 which supports the housing by means of ball bearings 16 . By means of a screw 18 , which acts on the bolt 14 , the pivot position of the housing can be adjusted and fixed. The adjustable feed 11 carries at its front end a ball 20 (or a ball cap), which can be advanced more or less by means of a threaded bolt 22 . The peculiarities of the device are now in the structural details explained below, which are explained by means of the thread course.

The thread (thread strand) is provided with reference numeral 24 . It enters the housing via the thread feed roller 4 , is guided via roller 6 , reaches roller 8 and from there to guide roller 10 and via ball 20 to thread deposit roller 12 and is transferred from this roller to a winding body 26 . Thread entry point 28 and thread exit point 30 , which coincides with the deposit point, lie on the pivot axis AA of the device.

As a result, the fiber strand 24 is fed to the winding mandrel 26 in all winding tasks via the always the same point 30 . This corresponds to a thread eye with diameter O. The arrangement ensures that the fiber strand is rotated even at a small angle, in the upstream section of the storage device, and not in the storage device.

The thread spreads through the combination of guide roller 10 , ball 20 and thread depositing roller 12 , the size of the spread being caused by the depth of penetration of the ball surface 20 into the thread course. Thread tension variations have no influence on the function of this device.

By the roll 12 lying directly on the mandrel 26 , the width of the fiber strand 24 obtained is obtained.

The contact pressure of the device is adjustable and enables smoothing and leveling the surface and rolling out  of the excess resin and thereby allows the production of Winding products with more than 70 vol.% Fiber content at opti painterly impregnation and equalizes fluctuations in resin content of the supplied fiber strand largely. Details of the Swiveling and pressing mechanisms are not shown.

The storage device also allows the thread to be deposited the same filing quality at winding angles between + 0 ° / 90 ° / -0 °.

The adaptation of the storage device to the respective winding angle can be done via a known belt turner control.

Claims (3)

1. A method for spreading an aligned fiber strand, which consists of parallel adjacent carbon fibers, a machine element with a convex surface penetrates into the fiber strand and fanned it out, characterized in that a saturated carbon fiber strand by penetration of a fiber length - And is spread in the fiber transverse convex machine element. 2. Device for performing the method according to claim 1, characterized in that the machine element with convex surface is a ball or ball cap. 3. Device according to claim 2, characterized in that the penetration depth of the ball or ball cap can be changed is.