US3663131A

US3663131A - Casting device

Info

Publication number: US3663131A
Application number: US135406A
Authority: US
Inventors: Fritz Hegewaldt
Original assignee: Bbc Brown Boveri & Cie
Current assignee: BBC Brown Boveri AG Germany
Priority date: 1968-01-03
Filing date: 1971-04-19
Publication date: 1972-05-16
Anticipated expiration: 1989-05-16
Also published as: CH473623A; FR1597257A; GB1219779A

Abstract

A device is provided for making castings conforming to a mold while leaving the impression of the casting preserved in the mass of particles of the casting material. There is a casting box containing loose magnetizable particles with which nonmagnetizable particles may be admixed and the casting is carried out through the action of magnetic forces generated either by electromagnets or permanent magnets and the casting action is continued at least until the casting becomes strong enough to be self-supporting. The source of the magnetic forces for carrying out the casting include at least one permanent magnet or electromagnet having one or more pole shoes which are adjustable relative to the casting box. Each magnet may be subdivided into a plurality of individual magnets. The casting box is mounted on guides of non-magnetic material which guides may be directly on the casting box or on the magnets or on their pole shoes. Simplified casting is obtained at reduced cost.

Description

[ 51 May 16,1972

[ CASTING DEVICE [72] Inventor: Fritz Hegewaldt,

Germany Herdecke-Kirchende,

[73] Assignee: Brown, Boveri & Cie Aktiengesellschaft,

Kallstadter Strasse, Mannheim-Kafertal, Germany [22] Filed: Apr. 19, 1971 [2|] Appl.No.: 135,406

Related U.S. Application Data [63] Continuation of Ser. No. 783,920, Dec. 16, 1968,

abandoned.

[30] Foreign Application Priority Data Jan. 3, 1968 Germany .P 16 08 039.0

[52] U.S. Cl. ..425/3, l8/DIG. 33, 164/349, 264/24, 264/111, 164/148, 425/453 [51] Int. Cl. ..B22c 15/00 [58] Field of Search ..264/24,l1l, 221; 18/DlG. 33, 18/39; 164/34, 48, 49, 250, 146, 147, 148, 349;

[56] References Cited UNITED STATES PATENTS 2,581,489 l/1952 Kilham ..18/DlG.33

3,216,074 1 1/1965 Harrison l 8/DIG. 33

FOREIGN PATENTS OR APPLlCATlON S 1,806,277 6/1970 Germany l 8/DIG. 33

Primary Examiner-Francis S. Husar Assistant Examiner.lames F. Coan [5 7] ABSTRACT A device is provided for making castings conforming to a mold while leaving the impression of the casting preserved in the mass of particles of the casting material. There is a casting box containing loose magnetizable particles with which non-magnetizable particles may be admixed and the casting is carried out through the action of magnetic forces generated either by electromagnets or permanent magnets and the casting action is continued at least until the casting becomes strong enough to be self-supporting. The source of the magnetic forces for carrying out the casting include at least one permanent magnet or electro-magnet having one or more pole shoes which are adjustable relative to the casting box. Each magnet may be subdivided into a plurality of individual magnets. The casting box is mounted on guides of non-magnetic material which guides may be directly on the casting box or on the magnets or on their pole shoes. Simplified casting is obtained at reduced cost.

5 Claims, 2 Drawing Figures CASTING DEVICE This application is a continuation of Ser. No. 783,920, filed Dec. 16, 1968, now abandoned.

This invention relates to electromagnetic or magnetic casting wherein a predetermined shape or object is formed conforming to a mold in loose magnetizable particles which may or may not be mixed with non-magnetizable particles and under conditions such that the impression of the cast articles or object remains preserved in the loose magnetizable particles. The casting is carried out by the application of magnetic forces to the magnetizable particles which are disposed in a casting box mounted in a suitable framework through nonmagnetizable connections. The magnetizable forces are applied until the shape to be produced from the magnetizable particles is at least strong enough to be self-supporting.

It is known from German Pat. No. 1,959,207 that magnetizable particles in the form of a loose agglomeration can be cast in a mold by means of an electrical field created by induction coils until the casting becomes solid. This procedure is recognized as being disadvantageous due to the relatively great cost resulting from the one or more induction coils disposed around the casting boxes particularly because the casting box has to be manipulated by raising or lowering it when it is introduced into or removed from circularly closed induction coils. When the casting boxes have been kept stationary in the past it has been necessary to move the induction coils up and down or relative to the casting boxes and this has been found to be either more complicated or more expensive.

According to the present invention magnetizable particles are cast into a predetermined or preselected shape or object utilizing generators of magnetic fields other than induction coils. In general this is accomplished by means of one or more magnets each of which has one or more pole shoes to create the cohesive forces necessary to consolidate the loose magnetizable casting material particles into the required form of shape. The loose magnetizable particles are not only initially unconnected to one another, but they can be admixed with non-magnetizable particles. Thus, the invention provides an entirely new means and method for making magnetic or electromagnetic castings and without the use of an induced magnetic field. The cohesive forces required to ring the loose magnetizable particles, with or without the admixed non-magnetizable particles, into the shape determined by the mold cavity can be created either by electromagnets or by permanent magnets which are highly advantageous and relatively inexpensive as compared with the prior known use of electrical fields generated by induction coils which latter are completely eliminated by the present invention. The construction of the casting device which is hereinafter described in detail has an advantage that the permanent magnets or electromagnets may be readily arranged or re-arranged with respect to the casting material so as to effect casting in the simplest manner and in the shortest period of time and for that purpose the magnets may be arranged opposite any desired surface of the casting box and may be divided into a plurality of smaller or individual magnets. Furthermore, the casting box is provided with non-magnetic guides or supports which do not interfere with the casting operation and which also serve to maintain the necessary spacing from the magnet to the pole shoes, each magnet being provided with one or more pole shoes and all the components of the casting device being relatively movable. The non-magnetic guides can also be arranged either on the casting box or on the magnets or on their pole shoes.

In the accompanying drawing which illustrates a preferred embodiment of the invention:

FIG. 1 shows a casting device according to the invention in cross-sectional view, and

FIG. 2 shows a plan view of FIG. 1.

Referring to the drawing in detail, casting box 1 made of any suitable or known material contains casting material 3 in the form of loose magnetizable particles of known material with which, if desired and depending on the particular casting to be produced and the use to which it is put, may be admixed therewith non-magnetizable particles. The casting material 3 has a cavity or mold 4 therein as shown and which may be of circular, oval, irregular or any other desired shape and size according to the casting which is to be produced and the cavity or mold may be maintained by means of a gasifiable or vaporizable material. It is to be understood that the particular mold cavity illustrated in the drawing constitutes no limitation on the invention, but is purely for purpose of exemplification. The casting box 1 is supported by and connected to

pivots

19,20 in the form of

double columns

21,22 supported on

base members

8,9 rising from a base surface or the ground and having as parts thereof the

pole shoes

5,6 by means of the

nonmagnetic guides

15,16 and this whole arrangement is movable or displaceable perpendicularly to the plane of the drawing in FIG. 1 by means of rollers 2 in a manner per se known.

The casting material 3 with its cavity or mold 4 are movable with casting box 1 with relation to the

pole shoes

5,6 which form part of the electromagnet 7 and there is a transverse member shown extending between

pivots

19,20 around which and in the space therebetween under the casting box 1 and rollers 2 it is connected by a field coil 10 which is a part of the electromagnet 7 and this field coil 10 is provided with suitable circuitry 11,12 as shown which connects the electromagnet and its field coil with a source of current (not shown). It is further to be observed that adjustable permanent magnets 13,14 are arranged parallel to the axes of the rollers 2, the magnet designated 13 being in operating position, whereas the magnet designated 14 has been displaced somewhat to make it possible to remove the casting box 1 from the

pole shoes

5 ,6 of the electromagnet 7 after the current supply has been discontinued. It will further be noted that

pole shoes

5,6 of the elec tromagnet 7 and the pole shoes of the permanent magnets 13,14 have exchangeable or replaceable non-magnetic guides heretofore referred to as 15,16 (FIG. 1) and additional nonmagnetic guides 17,18 (FIG. 2) By means of the

guides

15,16 casting box 1 can he slid or moved relative to rollers 2 in order to bring it to the correct distance from

pole shoes

5,6 at the time it is moved between those pole shoes for commencing the casting operation. In contrast,

guides

17,18 maintain the permanent magnets 13,14 at the prescribed distance from casting box 1.

The

pivots

19,20 above referred to in connection with the

double columns

21, 22 contain surface markings thereon (in FIG. 1) which have the significance that the strength of the magnetic field can be increased or decreased depending upon the mold cavity and the shape of the article or object to be cast and this is accomplished by relative shifting or rearrangement of the

pole shoes

5,6 of electromagnet 7. The amount and nature of re-arrangement is not only dependent upon the size and shape of the object or article to be cast, i.e. the configuration of the mold cavity, but the principles for doing this are themselves per se known.

It will, therefore, be seen that the invention obviates the necessity of using induction coils and moving them relative to the casting material and provides a superior and more economical casting device and method wherein relatively inexpensive and simple permanent magnets or electromagnets are employed which are easily adjustable in relation to the casting box for changing the field strength acting on the parti cles which are to be cast magnetically. Further advantage accrues in that it becomes possible with the present device to move the casting box when movement is required along a path which is level or substantially level thereby avoiding raising and lowering operations either of the casting box or the previously employed induction coils and this is especially advantageous when it is realized that the casting box may be relatively large and may contain a great amount of loose magnetizable particles and furthermore when the casting has been completed, the movement of the casting box is simple and easily carried out.

By way of example and without limiting the invention thereto, it is preferred to make casting box 1 of sheet iron or steel plate and the casting material 3 is formed of round steel grits of 0.2 to 2 mm in diameter. The vaporizable or gasifiable mold 4 is composed of foamed polystyrene. The preferred form of magnet is illustrated in the drawing wherein the electromagnets are supplied with direct current and have a magnetic flux of 10,000 to 12,000 gausses and an air gap of 1,500 gausses.

What is claimed is:

l. A device for magnetic casting in a casting box movable on rollers, comprising a casting box having a mold cavity formed in mold material of loose magnetizable particles and in which material the cavity is preserved until formation of a supporting wall thickness of casting by the action of magnetic forces, a stationary electromagnet to generate magnetic casting forces, a field coil for the electromagnet arranged below the rollers supporting the casting box and pole members for said electromagnet adjustable parallel to the direction of motion of the casting box at a distance therefrom on pivots and additional magnets enclosing the casting box displaceable perpendicularly to the direction of travel of the casting box to the extent that the casting box is advanced on the rollers.

2. A device for magnetic casting according to claim 1, wherein non-magnetizable particles are intermixed with magnetizable particles.

3. A device for magnetic casting according to claim 1, wherein guides of non-magnetic material extend from the casting box to the pole members of the magnets.

4. A device for magnetic casting according to claim 3, wherein the guides are on the magnets and one magnet is a stationary electromagnet the surfaces of whose pole members are parallel to the direction of motion of the casting box, said magnet being provided with a yoke and field coil located underneath the rollers.

5. A device for magnetic casting according to claim 1, wherein permanent magnets displaceable perpendicular to the direction of movement of the casting box are arranged for one to be moved in front of and the other to be moved behind the casting box.

Claims

1. A device for magnetic casting in a casting box movable on rollers, comprising a casting box having a mold cavity formed in mold material of loose magnetizable particles and in which material the cavity is preserved until formation of a supporting wall thickness of casting by the action of magnetic forces, a stationary electromagnet to generate magnetic casting forces, a field coil for the electromagnet arranged below the rollers supporting the casting box and pole members for said electromagnet adjustable parallel to the direction of motion of the casting box at a distance therefrom on pivots and additional magnets enclosing the casting box displaceable perpendicularly to the direction of travel of the casting box to the extent that the casting box is advanced on the rollers.