GB2129763A

GB2129763A - Method of making fiber-reinforced wound bodies

Info

Publication number: GB2129763A
Application number: GB08318744A
Authority: GB
Inventors: Bruno Sartor; Klaus Rode
Original assignee: Uranit GmbH
Current assignee: Uranit GmbH
Priority date: 1982-08-28
Filing date: 1983-07-11
Publication date: 1984-05-23
Also published as: DE3232087A1; JPH032053B2; DE3232087C2; NL190778C; GB8318744D0; AU1848583A; NL190778B; JPS5964329A; AU565263B2; NL8302320A; GB2129763B

Abstract

Layers of hardenable synthetic resin- saturated fibers are wound about a winding mandrel to build up the wound body thereon in the following steps: training a resin-absorbent web (5) partially about the winding mandrel subsequent to depositing at least one layer on the winding mandrel for establishing a contact zone between an upper surface portion of the deposited layer and the resin-absorbent web; moving the resin- absorbent web with respect to the winding mandrel; and maintaining pressure of the resin-absorbent web against the surface portion in the contact zone. <IMAGE>

Description

SPECIFICATION Method of making fiber-reinforced wound bodies Background of the invention This invention relates to a method of making fiber-reinforced, rotationally symmetrical wound bodies wherein fibers or fiber strands impregnated with a hardenable synthetic resin are wound in layers on a rotary winding mandrel and the wound body is removed from the mandrel after the hardening of the resin.

A wet winding method of the above-outlined type is disclosed in United States Patent No. 4,359,356 which is incorporated herewith by reference. In a wound body made according to the known method, the fiber strands contain, as a rule, a higher resin charge than the desired resin content intended for the wound body to be manufactured. Since the fiber strands are deposited onto the winding mandrel under tension, excess resin accumulates on the surface of the individual layers or, as the case may be, on the surface of the finished wound body. This occurrence may lead to inaccuracies in the wall thickness of the wound body. Such inaccuracies may result in impermissibly high imbalances if the wound body is used, for example, as a rotor in a centrifuge.

Summary of the invention It is an object of the invention to provide an improved method of the above-outlined type with which the resin accumulated on the surface of the individual layers or, as the case may be, on the surface of the finished wound body may be handled in a simple and rational manner such that there may be obtained a predeterminable ratio of resin content to fiber content of the individual layers or, as the case may be, there may be obtained, on the surface of the finished wound body, a resin layer with constant and predeterminable layer thickness.

This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, after the winding of the individual layers or, as the case may be, after the completion of the wound body, a resin absorbent band is trained partially about the winding mandrel and moved past the winding mandrel while in pressing contact with the upper surface of the top layer already wound on the mandrel.

By means of the method according to the invention, excess resin is drawn off and the resin remianing on the partially completed or fully completed wound body is distributed uniformly over the surface of the individual wound layers or, as the case may be, over the surface of the completed wound body.

The layer thickness of the resin remaining on the layers or on the outer surface of the finished wound body depends essentially from the set dwelling period of the absorbent band along the contact zone as well as from the absorbing capacity of the band.

The absorbent band may be, for example, a laminated paper felt or a woven textile fabric.

Brief description of the drawing Figure 1 is a schematic front elevational view of a device for performing a preferred embodiment of the method according to the invention.

Figure 2 is a schematic side elevational view of the structure illustrated in Figure 1, as viewed in the direction of the arrow A.

Description of the preferred embodiment Turning now to Figures 1 and 2, to a winding mandrel 3 there are applied in a manner disclosed, for example, in United States Patent No. 4,359,356, a plurality of layers composed of resin-impregnated fiber strands which eventually constitute a rotationally symmetrical wound body 9. Above the winding mandrel 3 there is arranged a supply reel or drum 1 on which an absorbent cloth web 5 is stored, and underneath the winding mandrel 3 there is positioned a take-up reel or drum 2 rotated by a drive 10 for winding thereon the web 5 with constant speed in such a manner that it is at all times partially trained (looped) about the uppermost layer of the wound body 9. The size of the contact zone 7 between the web 5 and the layer surface depends from the looping angle and the width of the web 5 and may therefore be varied within wide limits.

The direction of rotation (arrow 4) of the winding mandrel 3 and the direction of run (arrow 6) of the web 5 are oppositely oriented in the contact zone 7.

Referring in particularto Figure 2, the wound body 9 has a length which is several times greater than the width of the web 5. In order to ensure a uniform treatment of the surface of the wound body, the roller assembly 1,2 and 10, including the web 5, may be mounted on a carriage suspended, for example, from an overhead rail extending parallel to the axis 11 of the winding mandrel 3. The carriage, during run of the web 5 in the direction of the arrow 6, may be propelled with constant speed by an appropriate drive along the rail in the direction of the arrow 8.

The pressing force of the web 5 against the surface of the fiber layer in the contact zone 7 may be set by means of a brake acting on the supply drum 1. An optimal unwinding speed of the web 5 as well as the feeding speed of the web Sin the direction of the arrow 8 along the axis 11 of the winding mandrel 3 may be determined experimentally or by computation in order to achieve a uniform and defined resin layer on the surface of the individual layers or on the outer surface of the finished wound body 9. The operational parameters should be preferably selected in such a manner that the web 5 is just saturated with excess resin as it runs on the layer surface in the contact zone 7.

It will be understood that the above description of the present invention is susceptible to various changes, modifications and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended

claims.

CLAIMS 1. In a method of making a fiber-reinforced

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Method of making fiber-reinforced wound bodies Background of the invention This invention relates to a method of making fiber-reinforced, rotationally symmetrical wound bodies wherein fibers or fiber strands impregnated with a hardenable synthetic resin are wound in layers on a rotary winding mandrel and the wound body is removed from the mandrel after the hardening of the resin. A wet winding method of the above-outlined type is disclosed in United States Patent No. 4,359,356 which is incorporated herewith by reference. In a wound body made according to the known method, the fiber strands contain, as a rule, a higher resin charge than the desired resin content intended for the wound body to be manufactured. Since the fiber strands are deposited onto the winding mandrel under tension, excess resin accumulates on the surface of the individual layers or, as the case may be, on the surface of the finished wound body. This occurrence may lead to inaccuracies in the wall thickness of the wound body. Such inaccuracies may result in impermissibly high imbalances if the wound body is used, for example, as a rotor in a centrifuge. Summary of the invention It is an object of the invention to provide an improved method of the above-outlined type with which the resin accumulated on the surface of the individual layers or, as the case may be, on the surface of the finished wound body may be handled in a simple and rational manner such that there may be obtained a predeterminable ratio of resin content to fiber content of the individual layers or, as the case may be, there may be obtained, on the surface of the finished wound body, a resin layer with constant and predeterminable layer thickness. This object and others to become apparent as the specification progresses, are accomplished by the invention, according to which, briefly stated, after the winding of the individual layers or, as the case may be, after the completion of the wound body, a resin absorbent band is trained partially about the winding mandrel and moved past the winding mandrel while in pressing contact with the upper surface of the top layer already wound on the mandrel. By means of the method according to the invention, excess resin is drawn off and the resin remianing on the partially completed or fully completed wound body is distributed uniformly over the surface of the individual wound layers or, as the case may be, over the surface of the completed wound body. The layer thickness of the resin remaining on the layers or on the outer surface of the finished wound body depends essentially from the set dwelling period of the absorbent band along the contact zone as well as from the absorbing capacity of the band. The absorbent band may be, for example, a laminated paper felt or a woven textile fabric. Brief description of the drawing Figure 1 is a schematic front elevational view of a device for performing a preferred embodiment of the method according to the invention. Figure 2 is a schematic side elevational view of the structure illustrated in Figure 1, as viewed in the direction of the arrow A. Description of the preferred embodiment Turning now to Figures 1 and 2, to a winding mandrel 3 there are applied in a manner disclosed, for example, in United States Patent No. 4,359,356, a plurality of layers composed of resin-impregnated fiber strands which eventually constitute a rotationally symmetrical wound body 9. Above the winding mandrel 3 there is arranged a supply reel or drum 1 on which an absorbent cloth web 5 is stored, and underneath the winding mandrel 3 there is positioned a take-up reel or drum 2 rotated by a drive 10 for winding thereon the web 5 with constant speed in such a manner that it is at all times partially trained (looped) about the uppermost layer of the wound body 9. The size of the contact zone 7 between the web 5 and the layer surface depends from the looping angle and the width of the web 5 and may therefore be varied within wide limits. The direction of rotation (arrow 4) of the winding mandrel 3 and the direction of run (arrow 6) of the web 5 are oppositely oriented in the contact zone 7. Referring in particularto Figure 2, the wound body 9 has a length which is several times greater than the width of the web 5. In order to ensure a uniform treatment of the surface of the wound body, the roller assembly 1,2 and 10, including the web 5, may be mounted on a carriage suspended, for example, from an overhead rail extending parallel to the axis 11 of the winding mandrel 3. The carriage, during run of the web 5 in the direction of the arrow 6, may be propelled with constant speed by an appropriate drive along the rail in the direction of the arrow 8. The pressing force of the web 5 against the surface of the fiber layer in the contact zone 7 may be set by means of a brake acting on the supply drum 1. An optimal unwinding speed of the web 5 as well as the feeding speed of the web Sin the direction of the arrow 8 along the axis 11 of the winding mandrel 3 may be determined experimentally or by computation in order to achieve a uniform and defined resin layer on the surface of the individual layers or on the outer surface of the finished wound body 9. The operational parameters should be preferably selected in such a manner that the web 5 is just saturated with excess resin as it runs on the layer surface in the contact zone 7. It will be understood that the above description of the present invention is susceptible to various changes, modifications and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. CLAIMS

1. In a method of making a fiber-reinforced wound body including the step of winding layers of hardenable synthetic resin-saturated fibers about a winding mandrel to build up said wound body thereon, the improvement comprising the following steps: (a) training a resin-absorbent web partially about said winding mandrel subsequent to depositing at least one layer on said winding mandrel for establishing a contact zone between an upper surface portion of the deposited layer and the resinabsorbent web; (b) moving said resin-absorbent web with respect to said winding mandrel; and (c) during step (b), maintaining pressure of said resin-absorbent web against said surface portion in said contact zone.

2. A method as defined in claim 1, wherein step (b) comprises the step of moving said resinabsorbent web in a first direction; further comprising the step of rotating, during step (b), said winding mandrel in a second direction; said second direction being, in said contact zone, opposite to said first direction.

3. A method as defined in claim 1, wherein step (b) includes the step of moving said resin-absorbent web with a speed designed to effect a maximum possible charging of the resin-absorbent web with resin in the contact zone.

4. A method as defined in claim 1, wherein step (b) comprises the steps of pulling said resinabsorbent web from a supply reel and winding said resin-absorbent web on a take-up reel, whereby the resin-absorbent web, as it runs from the supply reel to the take-up reel, contacts said surface portion in said contact zone.

5. A method as defined in claim 4, wherein step (b) further comprises the step of moving said resin-absorbent web with a constant speed.

6. A method as defined in claim 4, wherein said winding mandrel has a rotary axis; further comprising the step of displacing, during step (b), said supply reel, said take-up reel and said resinabsorbent web as a unit parallel to said rotary axis.

7. A method as defined in claim 6, wherein the step of displacing includes the step of displacing said unit with constant speed.

8. A method as defined in claim 1, wherein said winding mandrel has a rotary axis and further wherein step (b) includes the step of moving said resin-absorbent web transversely to said axis and further comprising the step of displacing said resinabsorbent web parallel to said rotary axis during step (b).

9. A method as defined in claim 8, wherein the step of displacing includes the step of displacing said resin-absorbent web with constant speed.

10. A method of making a fiber-reinforced wound body substantially as hereinbefore described with referenced to and as illustrated in the accompanying drawings.