Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D25/00—Special casting characterised by the nature of the product
  • B22D25/02—Special casting characterised by the nature of the product by its peculiarity of shape; of works of art
• • A—HUMAN NECESSITIES
  • A44—HABERDASHERY; JEWELLERY
  • A44C—PERSONAL ADORNMENTS, e.g. JEWELLERY; COINS
  • A44C17/00—Gems or the like
  • A44C17/04—Setting gems in jewellery; Setting-tools

Definitions

• the invention is based on a method for producing set, cast pieces of jewelry.
• DE-38 24 574 A1 describes a lost-wax casting process for producing jewelry.
• a master model of the piece of jewelry is first produced.
• a master mold is produced by molding the master model.
• the molding can be done by pouring a molding compound, for example a two-component silicone-rubber mixture, into a container in which the master model is arranged, allowing the molding compound to harden, then cutting the body thus formed in half and that Takes original model. It is also possible to place the master model between two blocks of thermoplastic material and heat it under pressure until it plastically deforms and nestle against the master model, which creates a lifelike impression of the master model in the two blocks (DE-35 46 188 A1).
• a molding compound for example a two-component silicone-rubber mixture
• the two-part archetypes formed in this way are also called rubber molds because they usually consist of elastomeric material.
• a modeling compound in particular a wax, is then poured into such a master mold by casting or injection molding. After the modeling compound has cooled, the master mold is opened and the model is removed.
• Several models are usually put together to form a model tree and this is then embedded in a fireproof molding compound.
• the molding composition is understood here as "fire-resistant” if it withstands the action of a molten metal from which the piece of jewelry is made without changing its shape.
• the modeling compound of which the model tree is made is driven out by heating; if the modeling clay is a wax or a low melting metal, it is melted out (lost wax process); if the modeling clay is plastic, it is burned out.
• the molten metal from which the pieces of jewelry are to be made is then poured into the casting mold thus produced. So that the metal penetrates into the last corners and ramifications of the casting mold, it is rotated during casting (centrifugal casting) or the casting is supported by applying negative pressure (vacuum casting). After solidification and cooling, the tree consisting of the pieces of jewelry is removed from the mold and the pieces of jewelry are separated from one another.
• a master model of the piece of jewelry is made, in which the stones are set, and this master model is molded to form the master form.
• Such a master form which is a negative form of the piece of jewelry, accordingly contains recesses for the stones.
• the stones for the piece of jewelry are inserted into these recesses of the master mold, then the mold is poured or injected with the modeling compound and the model of the piece of jewelry formed in this way is further processed in the manner described above.
• FR-A-2 366 812 recommends a plastic that is expelled by a two-stage thermal process, namely by melting and subsequent shock-like heating to the temperature required for metal casting, at which the plastic is decomposed.
• Another disadvantage is that there is only a firm hold for the stone if it has exactly the same size and shape as the one that was used in the original model. However, this is not regularly the case, so that extensive rework on the cast piece of jewelry is necessary.
• the object of the present invention is to improve the method mentioned at the outset in such a way that stones which have been fitted exactly in the piece of jewelry can be obtained in the simplest possible manner without subsequent setting work on the piece of jewelry being necessary.
• a master model is first produced from the piece of jewelry to be produced.
• This master model has one or more settings corresponding to the number of gemstones provided, but the gemstones are not used in the master model.
• a prong setting e.g. the prongs that are supposed to hold the gemstones are not bent inward, but they retain their original orientation that they had before the insertion of gemstones.
• a negative form is then produced as the original form from the original model, in which no gemstone has yet been inserted, and a model of the piece of jewelry is cast in this original form.
• a wax is used as a modeling clay.
• the model produced in this way is now fitted with gemstones by inserting them into the sockets provided. Since the model is a positive form of the piece of jewelry, the stones can be inserted into the settings from the completely exposed top of the piece of jewelery like an original piece of jewelry, but do not have to be laboriously difficult as in the lost wax process accessible recesses of a negative form (original form) are inserted.
• the stones can be inserted into the sockets of the wax model, for example by means of a slim suction applicator, with the aid of which the respective stone is sucked in, picked up, inserted into the socket and then left therein by switching off the suction air. The stone then only needs to be fixed in the socket.
• the stones are preferably fixed in their holders by softening and plastically deforming them through the action of heat, and best of all by heating a tool adapted to the shape of the upper end of the holder, placed on the holder and pressing it on is deformed against the stone in a single step.
• a tool with a frame-shaped contact surface at its tip as a tool for plastically deforming the socket, which is placed on the edge of the frame socket and then pressed against the surrounding stone edge.
• a prong or grain holder uses a tool which has projections corresponding to the position of the prongs or grains, with which the heated tool is placed on the prongs or projections, as a result of which they soften, flow and encompass the adjacent stone edges, for which purpose a brief contact with the Tool is enough. It has been shown that all prongs or grains do not have to be deformed in order to fix the gemstones, because a prong deformed by the action of heat has more intimate contact with the stone edge than a metallic prong pressed in the conventional way against the stone edge. It is therefore preferred that only a subset of the prongs or grains is deformed in the case of claw or grained frames, while the rest remain undeformed.
• the stones are so easy to insert and fix in the model that even unskilled workers can master them after a short briefing.
• the method according to the invention is therefore particularly suitable for the industrial mass production of jewelry.
• the cost of setting gemstones can be drastically reduced: compared to the conventional technique of inserting the stones into the cast ring band, the cost of setting can be reduced to 1/10; compared to the conventional lost wax process, in which the stones are already poured into the wax model, the costs can still be reduced to 1/4.
• a master model is made of metal from a piece of jewelry, for example a ring, which should have several gemstones.
• the original model has prong settings for the stones, but the stones are not used.
• the master model is placed between two blocks of thermoplastic silicone elastomer, which are then heated and pressed against each other. As a result, the silicone elastomer is plastically deformed and clings to the original model, creating a lifelike impression of the original model in the two blocks.
• the two blocks formed in this way form the two parts of a master mold, into which a wax is then injected. After the wax has cooled, the master mold is opened and the wax model of the piece of jewelry is removed.
• the intended ones are made into the frames made of four prongs, for example, in the wax model Stones inserted and fixed by placing a fork-shaped tool, the two prongs of which are electrically heated and at a distance from two opposing prongs, on two opposing prongs of the respective setting and briefly pressing on them, which softens and compresses the prongs and the grasp each adjacent stone edge.
• a wax model tree is then formed in a manner known per se, inserted into a cuvette and poured out with a fine plaster, for example with alabaster.
• the cuvette is heated and the wax is melted out;
• the plaster cast of the wax model tree remains in the cuvette.
• the cuvette is heated to a temperature of approximately 750 ° C, placed in a centrifugal casting machine and cast in a molten 14-carat gold alloy, which is allowed to solidify in the rotating cuvette.
• the plaster is broken up, exposing the cast tree. The pieces of jewelry are now cut from the tree, cleaned and polished if necessary.
• the method described is particularly suitable for pieces of jewelry with small gemstones, for the setting of which one gets by with short prongs that are no more than 2.5 or 3 mm long.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Adornments (AREA)
• Cosmetics (AREA)
• Mold Materials And Core Materials (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=6446348

Family Applications (1)

Country Status (12)

Families Citing this family (17)

Family Cites Families (12)

• 1991
  • 1991-12-05 DE DE4140121A patent/DE4140121C2/de not_active Revoked
• 1992
  • 1992-12-03 AU AU30845/92A patent/AU674836B2/en not_active Expired - Fee Related
  • 1992-12-03 AT AT92924652T patent/ATE134488T1/de active
  • 1992-12-03 HU HU9401683A patent/HUT67814A/hu active IP Right Revival
  • 1992-12-03 SK SK676-94A patent/SK67694A3/sk unknown
  • 1992-12-03 DE DE59205524T patent/DE59205524D1/de not_active Expired - Fee Related
  • 1992-12-03 CA CA002125152A patent/CA2125152A1/en not_active Abandoned
  • 1992-12-03 JP JP5509833A patent/JPH07505061A/ja active Pending
  • 1992-12-03 EP EP92924652A patent/EP0615415B1/de not_active Expired - Lifetime
  • 1992-12-03 WO PCT/EP1992/002792 patent/WO1993010686A1/de not_active Application Discontinuation
  • 1992-12-03 CZ CZ941367A patent/CZ136794A3/cs unknown
  • 1992-12-05 CN CN92115193.4A patent/CN1078182A/zh active Pending
• 1994
  • 1994-06-03 FI FI942629A patent/FI942629A/fi not_active Application Discontinuation

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