US1849767A - Process of preparing molding sands for easily oxidizable metals such as magnesium - Google Patents

Description

-1 0 poured, an

general it will suffice to Patented Mar. 15, 1932 UNITED STATES PATENT OFFICE GILBERT mormr, 01'- naoxnux, Eamon, AssIeNon 'ro socmrn LE monrsmu mnusrnmv', or rams, FRANCE PROCESS or ranrname MOLDING Ho Drawing. Application filed March 24, 1928,

My invention relates to 'a process for the preparation of foundry sand.

In casting metals, it is usual to mix vegetable and mineral products of various kinds 5 with foundry sand either for improving the porosity of the molds, by their mere presence, by imparting suflicient plasticity and solidity to the sand mixture, or for producing, under the action of the heat from the metal being emission of gas, the said gas constituting and facilitating the ventilation of the mold or forming anneutral atmosphere insulating the cast metal from the mold and from the exterior atmosphere.

Such additions give very unsatisfactory results or failures, when-casting easily oxidizable metals and especially metals'such as magnesium which have a very great affinity for water contained in the material of which molds are made, and for oxygen and nitrogen; 7

Likewise as is known many attempts have been made to overcome these disadvantages, by mixing with the sand, certain vegetable products, such as resins, gums, rubber, certain salts and the like. All these products are either relatively high priced or donot easily give a sufficient homogeneity of the foundry sand, so that the results obtained are, in general, rather unsatisfactory.

My invention consists essentially in working up the sand for the molds, and when necessary that of the cores, with a suitable addition of pulverized graphite preferably mixed with more or less of an aqueous solution of ammonia. v

In molds involving a large quantity of sand, it is moreover necessary to thus prepare all of the sand for the mold,'because in provide a layer of graphite sand, several centimeters ness,-ar0undthe pattern, the rest of the' mold or corescan then be made of old sand, for example,

In making molds destined to be poured in thick- SANDS FOR EASILY OXEDIZABLE METALS SUCH AS MAGNESIUM Serial m..2s4,57a, and in France m 5, 1 aa7.

ing plasticity.

This process provides at least in the thick: ness of sand capable of being in contact with the fused metal, a sand which is sufliciently anhydrous and permeable to be without action on the fused metal, and more particularly. in connection with easily oxidizable metals.

As a final precaution, the parts of the mold with which the hot metal will come into contact, can be'coated over with a mixture of pulverized graphite and ammonia water. This coating moreover gives the cast metal an extremely brilliant aspect and does not produce, as is generally the case, a more or less oxidized surface.

A number of examples will now be given in which good results have been obtained.

In making a baked mold or. a green mold, for casting magnesium the following materials and proportions may be employed Kgs. White silicious sand (dry weight) 30 Ordinary yellow'sand (dry weight) 12 Naphthalene (pulverized) 0.600 Graphite (pulverized) 0.500 Ordinary agglomerants of commerce- 0.620

The complementary plasticity is obtained either by an ammomacal solution or by the addition of common water, when 7 making a baked mold. For making a. green.

of this sand Preferably, the power plant of the plane consists of two motors as above explained, and preferably each of these motors will develop one-half the total power required to navigate the ship. About one-half thetotal power will he usually required to sustain the weight of the plane and the other half will be required for propulsion and traction as well as for ascending. In the event of the failure of one motor, power developed by the other will be amply sufiicient to enable the pilot to maintain control and altitude until a suitable landing place can be located.

lit is not intended to limit the opposing sections of each wing to a single pair as four or more wing sections may be employed if desired. It will be pointed out that the rotating wings are rotated in opposite directions so that the torque will be neutralized. It will be further pointed out that the rotating wings interdigitate or mesh during rotation, However, it is not intended to limit the wing construction to intermeshing wings, since the wings may be spaced far enough apart so that they do not overlap, if desired.

In operation, the pitch of the wing sections is varied for traction as well as for ascent and descent. The pitch angle, of course, must be positive for taking oil, but for landing it need not necessarily be negative since the engines may be throttled down until the lifting force of the wings is decreased to less than the weight of the plane and it may then descend at a speed in proportion to the force resisting it. in case of a dead stick landing, it will be necessary to set the wings to a negative angle of probably four or five degrees so they will auto-rotate.

The variable pitch wing construction is of equal importance for traction purposes in a horizontal direction. Since the pitch which is efiicient for ascent or descent is comparatively fiat and therefore devoid of thrust in a horizontal direction, it is necessary to use the maximum pitch for horizontal flight partly to compensate for the air speed and partly to utilize all of the available motor power not utilized for sustaining the weight of the plane. In addition to using the maximum pitch of the wings, the angle of incidence of the wings must be increased, as shown by dotted lines in Fig. 2, that is, the wings must be inclined forward until the vertical component of thrust will just sustain the plane and the balance of the thrust will be utilized for traction.

From the above description, it is thought that the construction and operation of the invention will be clearly understood without further explanation.

Having thus described the invention, I claim;

1. in a helicopter, a rotary sustaining wing including a tubular-beam, wing sections swiveled on the ends of the beam, a steel cable housed in the beam and connected to said sections for equalizing the thrust of the sections on the beam, and means for varying the pitch of said sections on the beam.

2. In a helicopter, a rotary sustaining wing comprising a tubular beam, an axle secured to the beam for rotating the beam, opposed wing sections swivelly mounted on the ends of the beam, a cable housed in the beam and connecting said sections together, and a sliding sleeve on said axle operatively connected to the trailing edges of said sections for changing the pitch angle of the sections on said beam.

3. ln a helicopter, a rotary sustaining wing including a tubular beam, opposed wing sections swiveled on the ends of said beam, an axle secured to substantially the center point of the beam for rotating the beam, the inner ends of said sections being curved in the arc of a circle struck from said axle as a center, a steel cable loosely housed in said beam and rigidly secured at the ends to said sections, and tubular housings carried by said sections and pivotally receiving the ends of said beam,

said cable equalizing thrust of said beam on said housings due to centri fugal force exerted by said sections. 4-. In a helicopter, a rotary wing including a tubular beam. wing sections swiveled on the ends of said beam at substantially the centcrs of pressure of the sections, tubular housings carried by the sections and pivotally receiving said beam, and a cable housed within the beam and rigidly secured at the ends to said sections for equalizing the centrifugal thrust of said sections on the beam and housings thereof.

5. In a helicopter, a rotary wing comprising a tubular beam, wing sections of substantially identical structure as to camber, chord and bracing ribs, tubular housings carried within the internal structure of said wing sections and housing the ends of said beam, and a steel cable trained through said beam and rigidly secured to said sections. 6. In an airship, a fuselage, a truss projecting from opposite sides of the fuselage, rotary wings extending normally horizontally above the fuselage and carried by the ends of said truss, means for swinging the truss pendulum-like to tilt said wings and change the angle of incidence or thrust thereof, each wing comprising pivotally mounted opposing sections, and means operatable independently of said truss for changing the thrust angle 0 said sections. i v 7. In an airship, a fuselage, a control wheel therein, rotary wings carried by the fuselage and each comprising a beam and swivel opposing wing sections on the ends of the beam, axles carried by said beams midway between the wing sections thereof, sliding sleeves on said axles operatively connected to the trailing edges of said wing sections, a