SU132511A1 - Gypsum positive device - Google Patents

Description

The described device is intended for making positives, for example, from a human foot. The design of the device reduces the cost of positives.

The device consists of two interforms that interlock between each other, which are used to install models in them and then fill them with ferromagnetic material, each of which is provided with a magnetic conductor, four poles and pole pieces and coils.

The drawing shows a diagram of the device.

Each of the two half-forms of the device has a magnetic core 1 and four poles with pole pieces 2 and rolls 3. The bottom of the entire magnetic system is made of a non-magnetic material (textolite, getinax, etc.). When a constant electric current is passed through the coils, a uniform magnetic field arises between the poles. The polarity of the poles is chosen in such a way that when current is passed through the coils 3, the half-forms repel each other, thus achieving independence of the magnetic fields in the two magnetic systems and, consequently, the connector of the general form (device).

If a model of a non-magnetic material (plaster, glass, wood, brass, etc.) and the remaining space is filled into the air space between the poles of both half-molds and the remaining space with a loose ferromagnetic material (steel filings, powders, etc.), the magnetic field pattern will change; the magnetic flux will close along the path with the lowest magnetic resistance, i.e., through the ferromagnetic filler, not entering the space occupied by the non-magnetic Model.

The particles of the ferromagnetic aggregate are arranged by magnetic field lines and exactly the model configuration is repeated. After disconnecting the molds and removing the model, the ferromagnetic aggregate configuration is not disturbed. The half-mold connector and model removal are carried out with the current turned on. After removing the model, the half-molds are shifted and gypsum is poured into the resulting cavity. Some time after the gypsum solidifies, the coil 5 is disconnected from the current source, and the resulting positive is freely taken out.

Subject invention

A device for making plaster positives, for example, from a human foot, is distinguished by the fact that, in order to reduce the cost of positives, it consists of two closures, between them half-molds, serving them, for installing models in them, and then filling them with ferromagnetic material, each of which is equipped with a magnetic circuit, four poles with pole pieces and coils.