US2169279A - Method of molding - Google Patents

Description

Aug. 15, 1939 E. F. OYSTER METHOD OF MOLDING Filed Dec. 16, 1937 INVENTOR.

fim XMV r W A'T'ToRNEYs Patented Aug. 15, 1939 UNITED STATES METHOD OF MOLDING Earl F. Oyster, Shaker Heights, Ohio Application December 16, 1937, Serial No. 180,126

3 Claims.

My invention relates to certain new and usefui improvements in molding machines, and to an improved method by which molds are formed during the use of my improved molding machine.

The principal objects of the present invention are to provide a new method and apparatus for quickly, conveniently and economically producing molds preferably of the type wherein the material used in the formation of the molds is sand, and whereby the sand is uniformly packed, which is highly important and desirable in the production of uniform castings.

A further object of invention is to dispense with the well-known operation of jolting or jarring the sand vertically to compact it within the mold, and to provide mechanism which will imp-art a horizontal movement to the sand in all directions. I have found the latter method of compacting sand within a mold, produces a casting surface, which is considerably harder or denser than the surfaces heretofore obtainable by the jolting or jarring methods, to which reference has just been made.

It is a further object of my invention to actuate the well-known squeeze cylinder at the same time or shortly after horizontal movement of the sand is being effected by my improved device, which results in a mold being packed and completed in the time heretofore required for the squeezing operation only, thus saving considerable time and labor cost, as well as producing better molds, and more molds in a given period of time, than with methods heretofore practiced.

A still further object of myinvention is to provide a power-operated vibrator of simple construction, preferably attached to the sub-pattern plate, which may be mounted on springs thereby permitting it, the pattern plate, the pattern, flask and sand to be subjected to a horizontal movement in all directions, which nestles the sand grains around the pattern, thus presenting a very smooth casting surface to the molten metal when the mold is poured.

Some of the advantages gained by my improved method of vibrating the sand grains in a horizontal direction are, as distinguished from the jolting method, that less time is required in the production of the molds; smoother casting surfaces are produced and presented to the molten metal when the mold is poured; that the molds are more uniformly packed, which condition is highly desirable in foundry practice, as it prevents sand washes and results in smooth and clean castings; and that nestling of the sand grains is accomplished by horizontal vibrating movement,

PATENT OFFICE rather than a vertical jolting movement, the horizontal movement preferably taking place simultaneously with the actuation of the well-known squeeze cylinder.

The invention relates not only to the appara- 5 tus, but also to the method of making molds in the manner disclosed. Furthermore, additional objects and features of the invention will become apparent from the following description relating to the accompanying drawings, which show a pre- 10 fer-red form. The essential characteristics are summarized in the claims.

In the drawing, Fig, 1 is a side elevation of a molding machine, made in accordance with the present invention; Fig. 2 is a front elevation of 15 Fig. 1, shown partly broken away and in vertical section, to more clearly illustrate the invention; Fig. 3 is a plan view of Fig. 1, with the upper or swinging head shifted to one side as is the practice during loading the flask with sand.

The molding machine chosen by way of illustrating my invention may comprise a hollow, cylindrical base It], closed at its bottom, as at II, and in which is mounted for vertical movement, an inverted piston l2. Preferably formed inte- 5 gral with the cylinder, and to one side thereof, is a pedestal or upright frame member 13, the upper portion of which may pivotally support an arm M, as by pivot shaft l 5, the arm in turn supporting at its free end, a head member l6, which 30 may be swung to a position over the cylinder and piston, as shown in Figs. 1 and 2, when in use, or to one side thereof, as illustrated in Fig. 3, when not in use.

As best illustrated in Fig. 2, the upper end of 35 the piston may be provided with an integral flange l1, horizontally disposed and supplied with upwardly projecting stops, such as l8 and I9, which cooperate with corresponding stops 2H and 2!, preferably formed on the under side of a sub- 40 pattern plate 22. The plate, as shown, is horizontally disposed and yieldably supported above the piston and is spaced apart relative thereto, as for example, by a plurality of vertically disposed compression springs 23, retained between 4.5 the plate and flange, as by encircling suitable bosses 24 on the plate and flange, respectively. Thus it will be apparent that the sub-pattern plate is free to vibrate in a horizontal, as well as a vertical direction, above the piston, and that the stops limit the extent to which the springs may be compressed.

As previously pointed out, it is an object of myv invention to provide mechanism for imparting a horizontal vibrating motion to the material used in forming molds, as for example, sand, to thereby cause the sand grains to quickly settle or nestle around the pattern preferably at the same time they are being subjected to a squeezing action, and in this manner I have produced a new method of molding which eliminates the heretofore necessary jarring or jolting operation, prior to the squeezing operation.

I desire to obtain such horizontal motion of the sand, by employing a power-vibrating means, preferably carried by the sub-pattern plate, so that when a pattern plate 25 is placed upon the sub-plate 22, as shown in Fig. 2, and a flask 23 of conventional design or any other suitable container is placed thereupon and filled with loose sand, designated by reference numeral any movement of the sub-pattern plate will be imparted or transmitted to the sand.

One form of such vibrating mechanism for the sub-pattern plate may comprise an air turbine or motor, which, in the present instance, comprises a rotor housing 21, preferably formed in two parts and rigidly mounted upon the sub-pattern plate by any suitable means. The housing may be provided with an internal chamber to re ceive a rotor 28, having vanes 29 on its periph ery.

Projecting horizontally from the rotor housing 21 and in communication with the chamber 3 2, are tube--like extensions 3! and 32, which constitute inlet and outlet passageways, respectively, for the fluid used, such as compressed air. The rotor 28 is mounted for rotary movement within the chamber 30, as by a shaft 33, and carries an off-center weight 34, which, during rapid rotation of the rotor, produces the desired horizontal vibration utilized for packing the sand uniformly around the pattern 35 of the plate The squeezing operation of the sand 26 within the flask 36 may be accomplished by moving the piston l2 upwardly within the cylinder l9, which in turn, elevates the sub-pattern plate, the pattern plate and flask or other container, respectively, toward the head member I6, as will be apparent from Fig. 1.

Any suitable means may be employed for raising and lowering the piston within the cylinder, as for example, any motive fluid, such as compressed air, or oil, under pressure, either of which can readily be admitted to or released from the cylinder. When using air pressure, as the medium for rotating the turbine, it will be extremely economical to raise and lower the piston l 2 by air also, but it is to be expressly understood that while I have shown and described air as a medium for operating the turbine and the piston, this no way limits the scope or spirit of my invention, as any other suitable power means may be employed with equally successful results, for the purpose intended.

It may be desirable to provide a means or mechanism to prevent the piston l2 from rotating within the cylinder l during the operation of elevating or lowering said piston, and such mechanism may comprise a guide pin 3'], carried by the sub-pattern plate and projecting downwardly therefrom and slidably received by a bearing boss -8, carried by the outer periphery of the cylinder ii as shown in Fig. 2.

The pin. 3? may further be provided at its lower extremity with a nut or collar 39, which may serve as a stop or limit for the upward movement of the piston 12, by contacting the bearing boss 38.

Briefly, the operation of my improved molding machine, is as follows: With the head member l6 swung to one side, as shown in Fig. 3, the pattern plate supporting the container 36 may be placed upon the sub-pattern plate 22, and the container filled with sand 26. Power may then be applied to the rotor to impart horizontal vibrations to the sand. Power may be applied to elevate the piston I 2, thereby moving the flask or container 36 toward the head l6, which is swung to a position above the flask, as shown in Fig. 2, after the container has been filled with sand. When the rotor is caused to rotate, and being out of balance, due to the off-center weight 34, a very rapid and forceful vibratory movement will be imparted thereto, which movement, in turn, is imparted to the sub-pattern plate, pattern plate and container, respectively, which causes the sand to be likewise vibrated horizontally and firmly and uniformly packed about the pattern 35. If desired, the rotor may be actuated during the time the piston 12 is being elevated as this packing or nestling of the sand takes place very quickly and before the squeezing operation by the head l6 has been completed. As the sand container 36 advances toward the head l5, by the upward movement of the piston E2, the top portion of the sand 28 within the container will be compressed or squeezed, as it is termed, within the container until the pressure created is in excess of the tension of the springs 23, whereupon a relative movement takes place between the piston and the sub-pattern plate, which compresses the springs until the stops 2!] and 2! contact the stops it! and I9, and when this point of contraction is reached, the mold is completely packed, whereupon the operation of the turbine may be stopped, the piston i2 lowered, head it swung to one side, and the finished mold removed. Another container can then be mounted upon the pattern plate and the operation repeated. If desired, the pattern plate 25 may be removably secured to the sub-pattern plate 22.

Due to the fact that the pattern sub-plate is mounted upon springs, the rotating mass will subject the flask to a vibrating action, which causes the grains of sand to nestle together around all parts of the pattern. Then when the squeezing force is applied, the sand is packed with uniform density.

I claim:

1. The method of forming sand into a mold which comprises assembling the sand within a flask section in operative relation to a pattern and vibrating the flask by subjecting it to the action of a rotating off-center mass while the flask is resiliently supported.

2. The method of forming sand into a mold which comprises assembling the sand within a flask section in operative relation to a pattern, vibrating the flask by subjecting it to the action of a rotating off-center mass while the flask is resiliently supported and then subjecting the sand to vertical pressure.

3. The method of forming sand into a mold which comprises assembling the sand within a flask section in operative relation to a pattern, vibrating the flask by subjecting it to the action of a rotating off-center mass while the flask is resiliently supported and at the same time sub- 0 ectlng the sand to pressure by a squeezing action. 7

EARL F. OYSTER.

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