US2209792A - Molding machine - Google Patents

Description

July 30, 1940. R. A. PARKER 2,209,792

MOLDING MACHINE Filed Feb. 14, 1938 2 Sheets-Sheet. l

i INVENTOR.

* /7 j BY rfiqy/vavofl Pam E? ATTORNEY.

y so, 1940,

ARKER MOLDING MACHINE Filed Feb. 14, 1938 2 Sheets-S 2 57 Ill 1 I INVENTOR BY Harm APHRKEP ATTORN Patented July 30, 1940 UNITED STATES PATENTIOFFICE MOLDING MACHINE Raymond A. Parker, Cleveland, Ohio, assignor to The S P Incorporated, Cleveland, Ohio, a corporation of Ohio Application February 14, 1938, Serial No. 190,431

1'7 Claims.

This invention relates to foundry equipment and more particularly to an improved molding machine for producing molds from sand or other granular materials.

The present foundry practice of producing sand molds is to jolt the sand in a flask so as to directly settle the particles and subsequently apply pressure by the well known squeeze plate to compact the particles of sand around the pattern. The sand molds produced in this manner, while usable, possess inherent characteristics detrimental to the production of perfect or nearly perfect castings. In the first place, the permeability of the r sand forming the mold varies considerably and in many instances the casting produced therefrom varies materially from the pattern and is therefore, an imperfect casting. This necessitates expensive machining operations to place the casting in usable condition or results in the total loss of the casting in case it cannot be satisfactorily remedied. Another disadvantage in the present practice resides in the necessity of peening, ramming or tucking the sand, by manual operation, in order to improve the quality J. of the mold, all of which consumes considerable time thus resulting in increased production costs.

It is therefore, an object of the present invention in the production of sand molds to subject the sand in the flask to a series of rapid percusgrains or particles so that the latter may flow into one another, forming an interlocked porous body of uniform density and permeability.

Another object of the present invention is to 35. subject the grains or particles of sand while being agitated to a predetermined progressively applied pressure so as to assist the normal compacting of the grains or particles.

Another object of the present invention is to discontinue the agitation of the particles or grains of sand just prior to the application of the maximum pressure so that the grains or particles may settle themselves uniformly around the pattern and upon the application of the final or maximum pressure the sand particles are compressed into a homogeneous mass of substantially uniform.

density. v

A still further object of the present invention is to provide a molding machine having incorporated therein instrumentalities by means of which molds of sand or other granular material may be produced in accordance with the foregoing objects thus eliminating, to a great extent, former manual operations.

A still further object of the invention is to provide in such a machine a floating table upon which the mom: is produced and to subject the floating table to a series of rapidly applied percussive blows'which will agitate the sand particles in the desired manner but which will not transmit vibrations to other parts of the machine.

A still further object of the invention is to employ a plurality of vibrators acting upon the floating plate in a manner to equalize the effect of the blows so that the sand particles will be uniformly distributed over the plate and each subjected tosimilar agitation.

A still further object of the invention is to provide means for temporarily maintaining the floating table in rigid position during the application of the final or maximum pressure on the sand so that the sand particles will be uniformly compressed into a homogeneous mass of substantially uniform density.

A still further object of the invention is to provide means for automatically controlling the sequence of operations set forth in the foregoing objects.

Another object of the invention is to provide a molding machine of the type referred which is simple in construction and efficient in operation.

With the objects above indicated and other objects hereinafter explained in View, my invention consists in the construction and combination of elements hereinafter described and claimed.

Referring to the'drawings: I

Figure l is a side elevational View of a molding machine embodying the present invention.

Figure 2 is a front elevational view of the molding'machine with portions in section so as to more clearly illustrate the structural features, the section being taken substantially along the line 2-2 in Figure 3. 1 v

Figure 3 is a top plan view of the floating plate taken substantially along the line 3-3 in Figure 2.

Figure 4 is a fragmentary top plan View of the control valves and piping.

In the drawings, I have illustrated the invention embodied in one type' of molding machine but it should be understood thatthe principle may be as readily embodied in other types ofmachines and is not therefore, to be so limited, except as it may bedefined in combination).

The machine illustrated in the drawings comprises a base In having at its work end an upwardly extending squeeze cylinder ll formed integral therewith and preferably cast from semisteel material. The upper end of the cylinder II instance, is hollow and has an inner end wall I3 disposed transversely within the cylinder II while the opposite end is provided with a laterally projecting head I 4 substantially rectangular in shape. The head I4 has a central opening l5 for a purpose to be later described and the piston is preferably cast as an integral unit from semisteel material. The piston I2 is further provided with rings I6 so as to provide a fluid tight seal between the end of the piston and the interior of the squeeze cylinder II. The piston I2 is raised and lowered by means of air pressure introduced and discharged through an opening I! provided in the lower portion of the cylinder II below the end wall I3 and its operation will be later more fully described.

A floating table l8 consisting of flat sheet metal of rectangular shape corresponding to but slightly larger than the head I4 is disposed above the latter in spaced parallel relation, the upper side being smooth and adopted to support the necessary instrumentalities used in the production of a mold. The table I8 is resiliently supported by coiled springs I9 which are disposed between the inner adjacent sides of the table I8 and head I4. Any desired number of springs may be employed but in the present instance six are shown arranged in spaced relation so as to adequately support the table in a horizontal position as shown in Figures 1, 2, and 3. The springs I8 should be of sufficient strength to withstand the severe operations to which they are subjected and may be secured to the table and head in any desirable manner but preferably, with the use of centering lugs. While it is important that the table I8 be resiliently mounted during the major portion of the operations there is however, as will be later described, one operation which requires the table to be rigid or stationary and for this purpose cooperating stops or abutments 20 are provided. In the present instance, there are four pairs of stops shown, being so arranged that when the table is depressed excessively the adjacent pairs of stops engage with each other and provide a rigid abutment. While these stops 20 are here shown as being connected respectively with the table I8 and head I4, any other suitable manner may be adopted for the purpose intended.

One of the important features of the invention is to impart vibrations or percussive blows to the floating table I8 in such a manner that the sand particles on the latter will be equally agitated over the entire contacting surface. This may be accomplished in dilferent manners but preferably with the use of vibrators. By reason of many tests and experiments the best results are obtained by using four vibrators 2| arranged beneath the central portion of the table l8 and disposed approximately .90 degrees apart as viewed from the top, more clearly shown in Figure 3. Furthermore, the vibrators 2| should, preferably, be inclined in the direction shown in Figure 2, which tends to direct the impacts or blows so that the floating plate is vibrated in substantially vertical and rotating planes. A

simple way in which to mount the vibrators 2| is to provide hollow extensions 22 on the under side of the table l8 which arecentrally disposed and project downwardly and inwardly at an angle, the lower ends being disposed within the opening I 5 of the piston I2. The extensions 22 are provided with outer end walls 23 and inner end walls 24, the latter being connected together, if desired, to provide suflicient rigidity. The extensions 22 are open at their outer sides so that the vibrators 2| may be introduced therethrough and properly retained therein with the ends of the vibrators engaging the adjacent end walls 23 and 24. The vibrators 2| may be rigidly secured or removably secured within the extensions 22 as may be desired. The vibrators in the present instance are operated by air pressure introduced in any suitable manner and controlled in a manner to be later described, but other means for imparting rapid vibrations to the floating table may be employed where the same action upon the sand particles is obtained.

The vibrators 2I in the present instance are of small size and operate at approximately 4000 strokes per minute. Additionally the stroke of each vibrator differs slightly from that of the others so that synchronization of the vibrators is avoided. It will be apparent, therefore, that the floating table I8 is subjected to a series of tremendous impacts or blows causing it to vibrate upon its spring suspension but because of. this construction these vibrations are not transmitted to other parts of the machine, thus materially increasing the life of the machine and reducing the necessity of repairs or replacements.

At the rear portion of the machine is a standard 25 which extends upwardly from the base I!) and is of I section. This standard may be made as an integral part of the base or as a separate casting and bolted or otherwise secured thereto. The upper front portion of the web is recessed at 26 to provide a squeeze head support post 21 and lateral flanges 28 extend marginally around the web and unite at 29, to produce a rigid reinforced structure.

A squeeze plate arm 30 has a vertically arranged hub 3I at its inner end disposed within the recessed portion 26 of the squeeze head support post 21 and is provided with reduced extensions pivotally journalled in thrust shoes 3| which in turn are located on the opposite end walls of the recessed portion 26. The upper thrust shoe is bolted at 32 to the inner flange of the squeeze head support post 2'! while the lower thrust shoe isbolted at 33 to an extension 34 provided on the inner flange adjacent the base of the recessed portion 26. The lower reduced extension of the hub 3| preferably projects beyond the end of its supporting shoe and is mounted in a ballbearing thrust bearing 35 to facilitate swinging.

The opposite end of the arm 30 projects freely outwardly and has on its under side a squeeze plate 36 which is rectangular in shape and disposed in a horizontal position, the lower side being smooth. The squeeze plate 36 in the present instance is formed integral with the arm 30 and provides a rigid abutment against which the sand of the mold may be forced for compacting the latter.

To efl'ect operation of the vibrators and squeeze piston in the desired sequence different motive powers may be adopted, but for simplicity, convenience, and efiicient operation, air under pressure is employed. A distributing valve 3'! is mounted upon a plate 38 which is connected to the upper side of the squeeze plate 36 and is provided with an air inlet 39 connected with a source of air supply. Any desirable type of manually operable switch may be introduced into the air supply line to control the flow of air therethrough and this switch should preferably be located at a point convenient to the operator of the machine. The valve 31 has an outlet opening 40 the valve which is connected by a suitable conduit 4| with the plurality of vibrators 2|. The vibrators 2| may operate at line pressure and therefore the valve 31 merely passes the air therethrough in an unrestricted manner. A vibrator shut-off valve 42 is provided in the conduit.4| and is automatically operated to shut oif the flow of air for a purpose to be later described.

The valve 37 has a second outlet opening 43 of restricted size and is connected by a suitable conduit 44 with the opening IT in the lower portion of the squeeze cylinder I2. Thisconstricted opening permits the air to be gradually introduced into the interior of the squeeze cylinder where it exerts an upward pressure upon the end wall |3 of the piston causing the latter to rise. A relief valve 45 is placed in the conduit 44 for air for a purpose to be later described.

A second relief valve 45 is disposed adjacent .the vibrator shut-off valve 42. and has an inlet opening connected by suitable conduit 41 with the conduit 44 on the outlet side of the valve 31. The valve 45 also has an outlet opening connected by a suitable conduit 48 to the conduit 44 on the outlet side of the valve 45. This permits air to flow between the valve 31 and squeeze piston independently of the valve 45. The relation of these valves and their conduits can be more clearly seen in Figure 4.

The vibrator shut-off valve 42 has a projecting stem portion 49 which is connected to the valve member inside the valve body and the valve is normally open. The release valve 46 also has a projecting stem portion 50 which is connected to member inside the valve casing and this Valve is likewise, normally open. The valve 42 is controlled by the valve 46 and a suitable mechanism consists of a lever 5| having its forward end pivotally connected at 52 to the casing of the valve 42, the free arm of the lever extending across and contacting the projecting stem portions 49 and 50 of both Valves. A coiled spring 53 has one end connected to the free arm of the lever 50 and its other end connected to the plate 38 to continuously hold the lever in engagement with the projecting stern portions so that the valves will normally remain open.

The operation ofthe valve members is as follows: Air at line pressure is introduced into the valve 31 and passes directly to the vibrators 2| by reason of the valve 42 being open and thus causing the vibrators to operate. Part of the air is discharged through a restricted opening and is introduced gradually into the squeeze cylinder l2. This is permitted by reason of the valve as being ope-n. As the pressure in the cylinder builds up the piston is raised and when a predetermined pressure is reached (for which the valve 46 is set) the projecting stem portion 5!! ofthe valve 46 is forced outwardly causing the free end lever 5| to be raised which in turn releases the projecting stem portion 49 of the valve 42 and shuts oif the floor of air to the vibrators. Air however, continues to air supply line is shut off and the air in the sys tem is released in the customary manner.

In the production of molds according to the new method and with the use of the machine illustrated, a pattern plate 58, shown .in dotted of the flow into the squeeze cyl-' inder through the valve 45 (which is normally lines, is placed upon the floating table l8 and securely bolted in the customary manner. A flask 59, likewise shown in dotted lines, is positioned upon the pattern plate with its sides eX- tending around the pattern and its top open. The flask is next filled with molding sand, or other suitable material, so as tocover the pattern and provide sufiicient surplus material to produce the mold. A top board may or may not beused as desired, and if used, it fits within the open end of the flask, resting upon the sand.

When the flask is thus properly filled, the manual switch is operated to permit the air from the air supply line to enter the valve 31, from where it isconducted to the vibrators 2| which start their operation. The vibrators act upon the floating table in such a manner as to cause it to weave and wave. These weaves and waves crisscross one another forming a turbulent surface which, in acting upon the sand'particles contained in the flask, will cause them to be thrown or bounced about in vertical and rotating planes causing a similar turbulent motion of the sand particles. This movement of the sand particles causes them to flow into one another and interlock rapidly.

While the vibrators are thus operating air is also gradually admitted into the squeeze cylinder- |2 which causes the piston to rise and with it. of course, the floating table upon which the sand filled flask is supported. As the air pressure in the cylinder builds up the flask is raised until the top board engages the stationary squeeze plate 35, at which point, the application of pressure to the top of the sand in the flask is started. It has been found that certain pressures are more effective than others, in order to properly compact the sand particles about the pattern, and it is this predetermined pressure for which the shut-off valve 45 is set. This is the maximum pressure however, and the application thereof, should preferably be applied without the vibrator operation.

The vibrator relief valve 46 is therefore, set to close at a pressure somewhat less than the maximum pressure. When the pressure in the cylinder therefore, reaches that for which the relief valve 46 is set to close, the pressure causes the projecting stem portion 50 to move outwardly, which swings the lever 5| about its pivot away from the projecting stem portion 49 of the shut- Off valve 42 and permits the latter to close which shuts off the flow of air to the vibrators, inter-. rupting their operation.

The application of .pressure to the top of the sand in the flask concurrent with the operation of the vibrators, permits the gradual compacting of the particles while still in motion thus enabling the particles to be more intimately associated.

. While the valves 42 and 46 are closed, the air is still flowing to thecylinder by reason of the valve 45 being open. The introduction of this an causes a further upward movement of the piston, but the floating table I8 has moved its limit and the stops 20 are now in engagement with each other so that the table I8 is now rigid and the final pressure of the squeeze head on the sand in the flask is against a rigid support. When this final pressure has been applied to the maximum for which the valve 45 is set, it automatically closes and the air to the cylinder is cut off. In discontinuing the vibrations just prior to the application of the final pressure, the sand particles all settle themselves uniformly around the pattern without any so-called ram-offs or exv quired in foundry practice.

d. upon opposite sides of the machine raised or lowered in ceedingly soft spots. This produces molds that are absolutely true to pattern contour.

The operations described are rapid in sequence and eliminate manual operations formerly re- Broadly the invention contemplates the application of a series of rapidly applied impacts or vibrations to sand particles or other granular material, in a flask, to so agitate them that they will move in vertical and rotating planes thus flowing into one another to form an interlocked porous body. Also applying pressure to the sand particles while in a state of agitation to gradually compact the particles and finally applying pressure alone to cause the particles to closely interlock in a smaller space uniformly and compact into a homogeneous body of uniform density.

Of course, it is understood that a suitable stripper mechanism is employed for stripping the flask and mold from the pattern and its operation is well understood by those skilled in the art. In the drawings one type is illustrated which consists of four stripper rods slidably disposed in four openings provided adjacent the corners of :the floating table I 8. The upper ends of these rods project beyond the table surface and are positioned so asto engage the flange of the flask. The lower ends of adjacent pairs of rods are mounted in spaced arms 62 of yokes 63 disposed and below the table H3. The yokes 63 are slidably mounted on guide posts 64 which have their upper ends rigidly connected to the under side of the table l8 centrally thereof. These yokes 63 may be unison by any desirable means but as here shown by a pair of levers 65. These levers 65 have one of their ends secured to a cross shaft 66 which is rotatably journalled in a bearing provided on the inner side of the standard, while the opposite ends of the levers are free and extend beneath rollers 6'! mounted on the yokes. A link 68 has one endsecured to the shaft 66 and its other-end pivotally connected at 69 to the lower end of the link 70. The upper end of the link 10 is connected to a piston slidably mounted in a cylinder H which in turn is secured to the standard. This cylinder is likewise operated by air pressure and may be connected in the system so as to be supplied with air at a reduced pressure to depress the piston and raise the stripper rods when the table I8 is being elevated. The air to the cylinder H however, is shut off as the table is lowered after completion of the molding operations so that the rods engage the flask and hold it in an elevated position while the pattern is removed therefrom by the further lowering of the table.

While I have described the preferred embodyment of the invention it is to be understood that I am not to be limited thereto inasmuch as changes and modifications may be resorted to without departing from the spirit of the invention as defined in the appended claims.

What is claimed is:

1. In a molding machine, a table adapted to support a pattern and a flask filled with molding material, a vibrator obliquely disposed on the under side of said table for imparting percussive blows to the latter, a supporting base, and resilient means disposed between said base and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened.

2. In a molding machine, a table adapted to support a pattern and a flask filled with molding material, a vibrator obliquely disposed on the under side of said table for imparting percussive blows in two or more directions to the latter, a supporting base, and resilient means disposed between said base and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened.

3. In a molding machine, a table adapted to support a pattern and a flask filled with molding material, a vibrator obliquely disposed on the under side of said table for imparting percussive blows at high frequency in two or more directions to the latter, a supporting base, and resilient means disposed between said base and table for freely supporting the latter so that the blows imparted by said table will not be appreciably dampened.

4. In a molding machine, a table adapted to support a pattern and a flask filled with molding material, a plurality of vibrators obliquely disposed on the under side of said table for imparting percussive blows to the latter, a supporting base, and resilient means disposed between said base and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened.

5. In a molding machine, a table adapted to support a pattern and a flask filled with molding material, a plurality of vibrators obliquely disposed on the under side of said table for imparting percussive blows to the latter and spaced apart about the vertical center of said table, a supporting base, and resilient means disposed between said base and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened.

6. In a molding machine, a table adapted to support a pattern and a flask filled with moldingmaterial, a plurality of vibrators obliquely disposed on the under side of said table for imparting percussive blows to the latter, the strokes of said vibrators being of relatively different lengths to prevent synchronization, a supporting base, and resilient means disposed between said base and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened.

7. In a molding machine, a table adapted to support a pattern and a flask filled with molding material, a vibrator obliquely disposed on the under side of said table for imparting percussive blows to the latter, a supporting base, and a plurality of springs disposed between said base and table adjacent its outer edge for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened.

8. In a molding machine, a table adapted to support a pattern and a flask filled with molding material, a vibrator obliquely disposed on the under side of said table for imparting percussive blows to the latter, a supporting base, resilient means disposed between said base and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened, and stripper rods operatively mounted on the under side of said table and having free upper ends slidably mounted in said table.

9. In a molding machine, a table adapted to support a pattern and a flask filled with molding material, a vibrator obliquely disposed on the under side of said table for imparting percussive blows to the latter, a supporting base, resilient means disposed between said base and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened, and cooperating means on said base and table for effecting relative rigidity therebetween.

10. In a molding machine, a cylinder, a piston slidably mounted in said cylinder and having a laterally projecting head at its outer end, a table disposed above said head in spaced relation and adapted to support a pattern and a flask filled with molding material, a vibrator obliquely disposed on the under side of said table for imparting percussive blows to the latter, a plurality of coiled springs disposed between said head and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened and spaced apart relatively, and means for actuating said vibrator.

11. In a molding machine, a cylinder, a piston slidably mounted in said cylinder and having a laterally projecting head at its outer end, a table disposed above said head in spaced relation and adapted to support a pattern and a flask filled with molding material, a vibrator obliquely disposed on the under side of said table for imparting percussive blows to the latter, a plurality of coiled springs disposed between said head and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened and spaced apart relatively, cooperating means on said head and table for efiecting relative rigidity therebetween, and means for actuating said vibrator.

12. In a molding machine, a cylinder, a piston slidably mounted in said cylinder and having a laterally projecting head at its outer'end, a table disposed above said head in spaced relation and adapted to support a pattern and a flask filled with molding material, a vibrator obliquely disposed on the under side of said table for imparting percussive blows to the latter, a plurality of coiled springs disposed between said head and table for freely supporting the latter so that the blows imparted by said table will not be appreciably dampened and spaced apart relatively, a squeeze plate rigidly mounted above said table in spaced relation, means for actuating said vibrator, and means for actuating said piston in one direction to elevate said table into cooperative relation with respect to said squeeze plate whereby the molding material in the flask may be compressed while said table is freely supported.

13. In a molding machine, a cylinder, a piston slidably mounted in said cylinder and having a laterally projecting head at its outer end, a table disposed above said head in spaced relation and adapted to support a pattern and a flask filled with molding material, a vibrator obliquely disposed on the under side of said table for imparting percussive blows to the latter, a plurality of coiled springs disposed between said head and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened and spaced apart relatively, cooperating means on said head and table for effecting relative rigidity therebetween, a squeeze plate rigidly mounted above said table in spaced relation, means for actuating said vibrator, and

means for actuating said piston in one direction to elevate said table into cooperative relation with respect to said squeeze plate whereby the molding material in the flask may be compressed while said table is freely supported, further movement of said piston effecting relative rigidity of said table whereby the molding material in the flask may be finally compressed by the squeeze plate.

14. In a molding machine, a table adapted to support a pattern and a flask filled with granular,

molding material, a vibrator obliquely disposed on the underside of said table for imparting per cussive blows in opposite directions to the latter whereby said table is rapidly oscillated successively in different directions about its central portion, a supporting base, and resilient means disposed between said base and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened.

15. In a molding machine, a table adapted to support a pattern and a flask filled with granular molding material, a plurality of vibrators obliquely disposed upon the under side of said table for imparting percussive blows in different directions to the latter whereby said table is rapidly oscillated successively in different directions about its central portion, a supporting base, and resilient means disposed between said base and table for freely supporting the latter so that the blows imparted to said table will not be appreciably dampened.

16. The method of producing molds of sand or other granular material which comprises placing a pattern on a freely supported table, positioning a flask in cooperative relation about said pattern and resting upon said table, filling the flask with granular molding material to suitably cover the pattern, subjecting the table to a series of percussive blows rapidly applied in relatively two or more directions for effecting rocking of the table successively in different directions thereby imparting by settling and conveying motions to the granular particles to afford more intimate intermingling of the latter thus thereby producing a mold of more uniform density adjacent the mold cavity, and subsequently stripping the pattern from the mold.

17. The method of producing molds of sand or other granular material which comprises placing a pattern on a freely supported table, positioning a flask in cooperative relation about said pattern and resting upon said table, filling the flask with granular molding material to suitably cover the pattern, subjecting the table to a series CERTIFICATE OF CORRECTION. Patent No; 2,209,792; July 50, 191w.

momomn A. ,PARKER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, second column, lines 59 and 55, claimsl and 17 respectively, strike out the Word "relatively"; lines 14.2 and 58, strike out "by"; lines i l. and 60-61, same claims 16 and 17 respectively, strike out "thereby"; line 59, claim l7, strike out the article "a"; and that the said Letters Patent should be read with this 'correction therein that the same may conform to the rec- 0rd of the case in'the Patent Office.

Signed and sealed this 21 m day of September, A. D. 19).;0.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

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