Method of manufacture of a cold-moulded article.

The invention relates to a cold-cast molding, in particular thin-walled machine element withstand high dynamic loads, consisting of a produced casting of aggregates and binders, which is reinforced with a reinforcement, and a process for the preparation of the casting.

There are many complicated, thin-wall machine elements, such as housing, machine frames, tools, etc., which are now mainly made of steel or cast iron. For this expensive foundry models are necessary. The metal must be melted with high energy input. Finally, the castings must be cleaned. The effort is large and requires to avoid Committee careful work.

Why has it not lack of attempts, such parts beispielsweise from Polymerbeton by mixing Zuschlagstoffen with mostly harzartigen binders at Raumtemperatur watering. Unfortunately, the thin-walled moldings produced meet the high static and dynamic requirements in all cases, as they occur frequently especially in machine elements.

To the strength to increase, are in Spannglieder Stahlbetonbau used the generally small tears in Fertigteil with rarely occurring Höchstlast permit. These cracks, especially with frequent dynamic stress, as occurs in the machine, to the destruction of the machine element. This is especially true for thin Formteile, especially since the Überdeckung necessarily small. It is also difficult, the large dimensions of mechanical anchoring parts accommodate reasonable with small dimensions of the molded parts.

The object of the invention is to provide a Formteil - in particular a Maschinenelement - and a method for its production to be found, which avoids the aforementioned disadvantages.

In particular, the molding should be lightweight and structurally allow the formation of thin-walled parts without high static and dynamic stresses frequent cracking occurs or destruction occurs.

The Formteil is pleasing in appearance and be as few projections or edges to avoid contamination have.

The process should also at Einzelfertigung economically be what only for simple and low Arbeitsweise Investitionsaufwand possible.

The object is achieved in that individual tendons are arranged as a reinforcement, which are mounted to the anchoring points even after the solidification of the casting material in a direct Unhüllung plastic slidably.

By sliding each prestressed rod in its respective plastic wrap, it is possible to distribute locally occurring dynamic forces between the individual anchor points, which are preferably at the end of the tendons over a long way, so that no high local stress peaks occur, whereby cracks, are particularly in thin-walled moldings, avoided. These cracks can occur during dynamic stress on the one hand by direct failure of the material strength or the other by structural disruption due to the brittleness of the upcoming application for casting materials. Next direct shell single tendons also allows installation in thin walls, so that they can be placed exactly where the powers extend. This creates a high static and dynamic loadable Maschinenelement whose dynamic Dauerfestigkeit to the three-to vierfache be increased can.

The other Ausführungsformen are in the Unteransprüchen mentioned.

The use of clamping members with a low modulus of elasticity (- 50000 N / mm²) for example Polystal® which consists of unsaturated polyester resin with unidirectional glass fibers with a glass content of more than 70 wt .-% with at least one wrap of synthetic fibers is achieved an elongation which is particularly suitable for compensating larger changes in length of polymer concrete or mineral casting without substantial power loss.

The plastic covering of the tendon requires only a small thickness, since it is intended to prevent only the direct composite at the moment of casting. After solidification of the casting material, the contracting of the tension tendon can then move freely in the region surrounded by the plastic channel.

By installing several layers, especially with good Gleiteigenschaften, can be the lubricity improve. In particular, a Luftspalt possibly with Abstandshalter or Gleitschicht beispielsweise of Vaseline or silicone advantageous. Despite shrinkage or shrinkage of the casting material by sliding smoothly during tensioning or under dynamic demands is ensured.

By installing Kontrolleitern can jederzeit be examined whether the Spannglied yet its functions are fulfilled.

Finally, it can be anchored, for example, in polymer concrete or in Polymergußmasse by simply removing the plastic sheath over a length of at least 20 times, particularly 30 times, the diameter of the tendon. The thereby achieved adhesive strength is so high that about 50-60% of the breaking strength of the tendon can be achieved as an anchor. Simultaneously, the polymer compositions permit clean and corrosion resistant, dirt-corner free adaptation to the molding, particularly in thin-walled components.

The moldings, which may consist of thin-walled shells, are produced from a cold-setting casting compound, which consists of binders (water + cement, reaction resins) and aggregates (minerals) are cast. Erfindungsgemäß fall hierunter all known casting compositions as beispielsweise zementgebundene concretes, concretes polymermodifizierte, Reaktionsharzbeton and mineral casting.

As Polymervergußmassen polyester, acrylic, polyurethane, phenolic, epoxy resins can be used with fine fillers of silanized quartz and / or barite flours.

The tendons comprise reactive resins such as epoxy resins, polyester resins, polyurethane resins having unidirectionally aligned reinforcing fibers, for example glass fibers (e-glass, SGlas) having a modulus of 40 to 60,000 N / mm² or aramid fibers having a modulus of elasticity from 50 to 70,000 N / mm².

For the plastic sheath polyolefins, polyamides, thermoplastic polyesters, polycarbonates, thermoplastic elastomers, and polyvinyl chloride may be used.

An example of the invention is shown in the drawings. Show it<ul><li>FIG. 1 cold cast molding</li><li>Fig. 2 form with built-tendon</li><li>Fig. 3 form part of the time of bias</li></ul>

In Fig. 1, a mold 1 is shown, which consists of the actual casting second Within this casting individual prestressed tendons 3 are arranged unsaturated polyester with unidirectional glass fibers, which are provided in the central region with a plastic sheath and the undisguised ends as anchoring points 5, 6 directly in cold molded cast material 7 from binding agents and additives, or a sealing compound 8 are fixed, for example, from polymer concrete.

In Figure 2, a blank form is drawn 9 with a clamping member 3 which is held at both ends in the wall 10 of the mold 9 having a clamping device eleventh At the Verankerungsstellen 5, 6 is the wrapper 4 made of plastic at least a length of 30 x wire φ for later anchoring been removed.

In Fig. 3 a tensioning device 12 is arranged on one side of the raw casting 2, with the clamping member 3 is clamped. About a channel 13, the encapsulant 8 is injected and cured directly into the chamber 15 from a press 14th

In the claimed process thus be in a form 9 individual tendons 3, the anchoring points 5, 6 are exposed from the sheath 4, respectively. The actual casting 2 is from a cold angemachten mixture of binders and Zuschlagstoffen cast. After hardening or achieving an appropriate state for biasing each tendon 3 is biased by a tensioning device 12 and in the past within the casting chamber 2 15 cast directly on a sealing compound. 8