WO2018104977A1

WO2018104977A1 - Assembly of a gas torch and housing structure of said gas torch, in particular for a workbench for manual operations of preparation of wax models and clusters of wax models, in a process of manufacturing products by means of lost wax micro casting

Info

Publication number: WO2018104977A1
Application number: PCT/IT2017/050001
Authority: WO
Inventors: Mario IORLANO; Gerardo STRAZZA
Original assignee: Strazza Srl; Europea Microfusioni Aerospaziali SpA
Current assignee: Strazza Srl; Europea Microfusioni Aerospaziali SpA
Priority date: 2016-12-05
Filing date: 2017-12-04
Publication date: 2018-06-14
Anticipated expiration: 2019-06-05
Also published as: IT201600122904A1

Abstract

The present invention concerns an assembly of a gas torch and housing structure (10) of said gas torch, in particular for a workbench for manual operations of preparation of wax models and clusters of wax models, in a process of manufacturing products by means of lost wax micro casting, wherein said housing structure (10) comprises: two brackets (11) with a spade-like extremity (12), in correspondence of said spade-like extremity (12) of each of said brackets (11) removable coupling means being placed; a base (14), said base (14) defining a spacing zone (15), on the side of said spacing zone (15) being placed more distant from said brackets (11) a flame stop plate (16) being present; and wherein said gas torch comprises, on each of its extremities, removable coupling means apt to cooperate with said removable coupling means of said brackets (11).

Description

Assembly of a gas torch and housing structure of said gas torch, in particular for a workbench for manual operations of preparation of wax models and clusters of wax models, in a process of manufacturing products by means of lost wax micro casting

The present invention concerns an assembly of a gas torch and a housing structure of said gas torch, in particular for a workbench for manual operations of preparation of wax models and clusters of wax models, in a process of manufacturing products by means of lost wax micro casting.

It is known that the process of lost wax micro casting is commonly used, for example, for the production of aeronautical or industrial components made of metallic material, which can generally be of the equiaxal type, or directional solidification (DS), or "single crystal" solidification (SX).

According to the process of lost wax micro casting, the components are manufactured by preliminarily preparing a mould in which melted wax is injected and solidifying by cooling, makes it possible to obtain a model identical to the final component to be produced.

The wax model is obtained by injection using piston presses. These machines inject molten wax into a mold according to well-defined parameters that depend on the geometry of the part and therefore on the complexity of the mold to be filled.

Typically, many models are brought together to form a so-called cluster.

The clusters are then covered with a shell made up of a plurality of layers of refractory material, in order to give the shell the necessary toughness.

Each refractory layer is formed by means of three main steps:

a) immersion of the cluster of wax in a semi-liquid refractory dough, in particular of ceramic material;

b) drainage of the cluster; and

c) sprinkling of the cluster with sand or refractory stucco. The shell is then de-waxed, i. e. the wax around which the shell is formed is evacuated and then treated in high temperature furnaces. The shell thus obtained is therefore able to accommodate the casting of molten metal.

In particular, the component obtained by "single crystal" (SX) solidification is manufactured by placing the shell of refractory material in a vacuum furnace and exactly on a water-cooled platform to begin the solidification process. The molten metal is cast into the shell, and the "solidification rate" and "direction" are controlled by the speed of extraction of the melting chamber, and by a helical selector that, when the shell is removed from the oven, selects a single crystal, from which the component will be formed.

After cooling of the metal, the ceramic shell is removed by crushing it and then the individual components are finished.

In particular, the process of production by means of lost wax micro- casting requires manual processes to be carried out on wax parts in the post-injection moulding step to prepare them for the subsequent steps.

These are the so-called "wax pattern preparation" and "cluster assembly" operations.

With the first operation, all surface finishing operations are carried out on the wax components coming from the injection moulding operation, and in particular the removal of excess mould and burrs lines and the sealing between wax parts and accessories.

With the second operation it is possible to assemble on a cluster the prepared models, this cluster being able to have different configuration depending on the product family.

In order to carry out these manual operations on wax parts, appropriately prepared positioning/workbenches are used. These workbenches are equipped with a series of tools useful for carrying out the work, such as a series of spatulas for wax processing, a gas torch, useful for heating the spatulas themselves, or even directly the wax model, a heating element to dissolve additional quantities of wax needed for sealing separate parts to form a cluster. In the case wherein the machining operations are aimed at the production of small products, such as, for example, small aviation type blades, the handling of clusters during assembly does not require the use of any particular tool; on the other hand, the machining of large pieces, such as industrial type blades, requires the help of cluster lifting and handling equipment.

In particular, as far as the gas torch is concerned, this instrument is used to heat the spatulas for wax modelling, to flame waxes and to heat the platinum pins which, according to particular processes, must be able to be embedded in the wax until they touch the core. The gas torch has the characteristic of being very handy, having the handle made of bakelite and the end part in brass, and is connected with a rubber tube, specific for the gas, upstream of which there are two regulators that regulate the flow of gas and air

Typically, the gas torch is constantly lit for a whole work cycle, so it is important to orient the flame well and position it in a stable position, in order to avoid possible accidents.

For this purpose, it is necessary to create a housing structure of the gas torch, hereinafter also referred to as torch-holder, which according to prior solution was made up of a U-bent bracket with spade terminal on both sides and a flame stop plate, consisting of an L-bent metal sheet, placed in front of said torch-holder. The problem with this solution was that the gas torch, not being sufficiently stable, could turn around in relation to its intended position, endangering the safety of operators and the flammability of surrounding objects. In addition, to allow the flame stop plate to always be in the ideal position with respect to torch gas resting on the torch-holder, both torch-holder and flame stop plate were fixed to the work surface. However, this solution had limitations, given the position of the torch-holder and flame stop plate very close to that of the wax melting device, located behind the former, with the consequence that the wax melting device was also limited in its movements, making cleaning, maintenance and calibration difficult.

In this context, the solution according to the present invention, which aims to provide an assembly of a gas torch and a housing structure of said gas torch is introduced, in particular for a workbench for manual operations of preparation of wax models and clusters of wax models, in a process of manufacturing products by means of lost wax micro casting, apt to solve all problems associated with the use of the previous torches and torch-holders, in particular by ensuring structural integration of the flame stop plate in the structure of the torch-holder, a non-permanent and instantaneously removable torch-holder attachment to the work surface, and a non-permanent and instantaneously removable torch-holder attachment to the torch-holder.

The aim of the present invention is therefore to provide an assembly of a gas torch and a housing structure of said gas torch, in particular for a workbench for manual operations of preparation of wax models and clusters of wax models, in a process of manufacturing products by means of lost wax micro casting, which makes it possible to overcome the limits of the torch holders used in production processes by means of lost wax micro-casting using known technology and to obtain the technical results described above.

A further aim of the invention is that said assembly of a gas torch and housing structure of said gas torch can be realized with substantially low costs, both in terms of production costs and operating costs.

Not the last aim of the invention is to propose an assembly of a gas torch and a housing structure of said gas torch, in particular for a workbench for manual operations of preparation of wax models and clusters of wax models, in a process of manufacturing products by means of lost wax micro casting which is simple, safe and reliable.

Therefore, it forms a specific object of the present invention an assembly of a gas torch and housing structure of said gas torch, in particular for a workbench for manual operations of preparation of wax models and clusters of wax models, in a process of manufacturing products by means of lost wax micro casting, wherein said housing structure comprises: two brackets with a spade-like extremity, in correspondence of said spade-like extremity of each of said brackets removable coupling means being placed; a base, said base defining a spacing zone, on the side of said spacing zone being placed more distant from said brackets a flame stop plate being present;

and wherein said gas torch comprises, on each of its extremities, removable coupling means apt to cooperate with said removable coupling means of said brackets.

Preferably, according to the present invention said removable coupling means of each of said brackets comprise a magnet and said removable coupling means of said gas torch comprise a bushing/ring of ferromagnetic material.

Still according to the invention, said base is provided with removable coupling means of said base with a work surface, which preferably comprise a magnet.

In particular, always according to the invention, said housing structure is open in its upper part and on one or on both sides.

Lastly, accoding to the present invention, said brackets and said flame stop plate can be fixed to said base or integral with said base.

The present invention will now be described, by way of illustration, but not as a limitation, according to a preferred embodiment, with particular reference to the attached figure, wherein is shown a perspective view of the whole housing structure of a gas torch according to the present invention, in particular for a workbench for manual operations of preparation of wax models and clusters of wax models, in a process of manufacturing products by means of lost wax micro casting.

Referring to the figure it is shown a housing structure of a gas torch according to the present invention, the housing structure being indicated as a whole with the numerical reference 10 and being constituted by a single object, made of metal material, combining a torch-holder and a flame stop plate. In particular, the housing structure 10 comprises two brackets 1 1 , with a spade-like extremity 12, for the housing of a torch, not shown. Nearby each of the two spade-like terminals 12, a magnet 13 is fixed, the function of which is to collaborate with a steel bushing/ring on each of the two ends of a gas torch according to the present invention, so as to keep the torch in a stable position, but without preventing it from being caught, thanks to the magnetic attraction of the two magnets on the steel bushings/ring of the gas torch.

The housing structure 10 additionally comprises a third magnet, placed at the base 14 of the housing structure 10, to form a non- permanent and instantaneously removable attachment of the housing structure 10 to the work surface, which in turn is normally made of steel already according to the prior art.

The two brackets 1 1 of the housing structure 10 are fixed or made integral with the base 14, the latter also defining a spacing zone 15, on the side of which which is opposite to said brackets 1 1 a flame stop plate 16 being fixed or made integral with the base 14.

In the upper part, housing structure 10 is open to allow for a space, accessible from above, between said brackets 1 1 and said flame stop plate 16. In this way, the housing structure 10 allows to carry the spatulas to be heated during the operations carried out on the workbench, directly against the flame, supporting the spatulas from top to bottom without any problems.

The present invention has been described by way of illustration, but not as a limitation, according to its preferred embodiments, but it is intended that changes and/or modifications may be made by the experts in the field without departing from its scope of protection, as defined by the attached claims.

Claims

1 ) Assembly of a gas torch and housing structure (10) of said gas torch, in particular for a workbench for manual operations of preparation of wax models and clusters of wax models, in a process of manufacturing products by means of lost wax micro casting, wherein said housing structure (10) comprises: two brackets (1 1 ) with a spade-like extremity (12), in correspondence of said spade-like extremity (12) of each of said brackets (1 1 ) removable coupling means being placed; a base (14), said base (14) defining a spacing zone (15), on the side of said spacing zone (15) being placed more distant from said brackets (1 1 ) a flame stop plate (16) being present;

and wherein said gas torch comprises, on each of its extremities, removable coupling means apt to cooperate with said removable coupling means of said brackets (1 1 ).

2) Assembly of a gas torch and housing structure (10) of a gas torch according to claim 1 , characterised in that said removable coupling means of each of said brackets (1 1 ) comprise a magnet (13) and said removable coupling means of said gas torch comprise a bushing/ring of ferromagnetic material.

3) Assembly of a gas torch and housing structure (10) of a gas torch according to claim 1 or 2, characterised in that said base (14) is provided with removable coupling means for coupling said base (14) with a work surface.

4) Assembly of a gas torch and housing structure (10) of a gas torch according to claim 3, characterised in that said removable coupling means of said base (14) with a work surface comprise a magnet.

5) Assembly of a gas torch and housing structure (10) of a gas torch according to any one of the preceding claims, characterised in that said housing structure (10) is open in its upper part.

6) Assembly of a gas torch and housing structure (10) of a gas torch according to any one of the preceding claims, characterised in that said housing structure (10) is open on one side or on both sides.

7) Assembly of a gas torch and housing structure (10) of a gas torch according to any one of the preceding claims, characterised in that said brackets (1 1 ) are fixed to said base (14) or are integral with said base (14).

8) Assembly of a gas torch and housing structure (10) of a gas torch according to any one of the preceding claims, characterised in that said flame stop plate (16) is fixed to said base (14) or is integral with said base (14).