US2204407A - Molding machine - Google Patents

Description

J 1940- J. FLAMMANG ET AL momma momma Filed July 20, 1936 2 Sheets-Sheet 1 June 11, 1940. FLAMMANG 2,204,407

MOLDING MACHINE Filed July 20, 1936 2 Sheets-Sheet 2 Patented June 11, 1940 MOLDING nmcumn John Flammang and Percy L. Bowser, St. Louis, Mo., assignors to The Sterling Corporation, St. Louis, Mo., a corporation of Delaware v Application July 20, 1936, Serial No. 91,456

Claim.

This invention pertains to molding machines and more particularly to a machine for molding trunk pistons such as are used in internal combustion engines. 7 5 One of the object s'in this invention is to provide a machine by means of which pistonsmay be cast with improved accuracy and in such a manner that inaccuracies may be more easily detected.

Another object is to provide a machine whereby the various sections of mold and core may be separated and reassembled by operation of the machine so that when reassembled the various parts will be accurately positioned with respect to one another so as to form a true casting.

Another object is to provide improvements in the gate structure whereby the pouring operation may be so improved as to provide better assurance for sound castings. I v

Another object is to provide automatic mechanism for operating sectional molds and cores which will operate rapidly and accurately and which will be safeguarded against mistakes of the operator.

Further objects will appear from the following. description taken in connection with the ac companying drawings in which:

Figure l is a front view of a molding machine embodying this invention,

Figure 2 is a side view of Figure 1, Figure 3 is a top view of the mold cap. Figure 4 is a bottom view of the cap shown in Figure 3,

Figure 5 is a section on line 5-5 of Figure 3, Figure 6 is a detail of the drag block, Figure 7 is an enlarged detail of Figure 1, Figure 8 is a detail of the safety lock; and Figure 9 is a longitudinal sectional view of a defective piston casting.

Referring now to the drawings I designates a supporting frame in which is mounted upon trunnions 2 a supporting bracket 3 which in-turn carries a horizontally extending base 4. Mounted on the base 4 is a piston mold comprising 45 a pair of separable sections 5 surmounted by a mold cap 5, also sectionalized so as to open with the sections 5. Mounted inthe base 4 are upper and lower locating rings I and 8 respectively in which the core for the mold is mount- 50 ed. In the machine illustrated the core is made up of three sections, namely a center section 5 and two side sections III. The side sections ID aremounted in suitable channels in one of the locating-rings I or 8 so that when the center section 9 is withdrawn downwardly the side sections may be moved inwardly into the space vacated by the section 5; v

In order to render the side mold sections 5 slidable upon the base 4, there is provided for'each section 5 a carrier or angle plate H.- Suitable 6 guides it are provided to guide the carriers i I so that the mold sections 5 will move toward and away from each other in a'straight line. Mounted at each end of the base 4 is a-fluid pressure cylinder l3 havinga piston'rod ll connected to 10 the carrier ll so as to move the same back and forth in accordance with the fluid pressure introduced into the cylinder It. The piston rod H is releasably' connected tolthe carrier II. In order to make such connections the carrier is 15 provided with four upstanding posts i5 spaced laterally of the carrier so as to permit the pasfsage therebetween of the rod I4 and nuts l6 thereon, and spaced longitudinally so as to receive therebetween 'a drag block II. The rod i4 20 has mounted thereon a collar II which is clamped in adjusted position upon the rod It by means of the nuts l6 which'provide stops for the block l1. The drag block I1 is provided with a notch l9 arranged to fit over the collar l8. By propg5 erly positioning the collar l8 between the posts l5 and then slipping the drag block l'l over the collar. between the posts. a connection is established between the rod I4 and the carrier II, V

which provide respectively driving and driven 30 members with which the block I1 is only loosely engaged, This connection is easily broken or released by simply removing the block I! without disturbing any other element of the connections, between the power device l3 and the mold 35 section.

Mounted on the lower end of the bracket 3 is a fluid pressure cylinder 20 having a piston rod 2| upon the upper end of which the center core section 9 is mounted. Suitable means not shown are provided forcontrolling the admission of fluid pressureto the cylinders l3 and 20 in proper order so as to draw back the mold sections 5 and to withdraw-the center core section 5 downwardly. The side core, sections ll are mounted in a guide passages 22 in one or the other of the rings 1 and 8 so" that they may be moved inwardly of the mold into the space vacated by the section 5 and in a rectilinear-path so as to move clear of the interior portions of the casting without 0 danger of marring the same. This movement ot the side core sections may be accomplished manually by the operator by means of handles 25 suitably connected to the core sections.

In order to prevent the side sections II from cleared the space between them,

.ing mechanism is suitable sockets 25 in sectionsllo. Each pin 24 is carried by a block 26 adjustably' mounted upon a vertically slidable rod 21. Each rod 21 may be guided in a suitable bracket 28 mounted on the bracket 3 and a spring 23 engaging the bracket 28 the block 23 serves to urge the rod 21 upwardly. This upward movement is arrested by engagement of its upper end with the top plate 30 of the bracket 3. The two rods 21 are joined at their lower ends by a cross member 3| having a perforation 32 at its center through which the piston rod 2| may pass. The rod 2| slides freely through the perforation 32 so that when it moves downwardly to withdraw the center section 3, at the lower extremity of its movement and after the section 3 has cleared the two side sections [0, a head 33; adjustable on the rod 2|, engages the cross-member 3|, drawing it downwardly and thereby withdrawing the pins 24 from the sockets 25 and releasing the side sections l3 for inward movement to free the casting. The lower ends of the side sections ID are beveled outwardly as shown at '34 so that incase the side sections should still be in collapsed position when the center section 3 starts its upward movement to its casting position, the

' beveled surfaces 34 may serve as cam surfaces to cause the section 3 to force the sections I0 outwardly as it rises. As soon as the section 3 begins to rise the head 33 releases the cross-member 3|, whereupon the spring 23 returns the pins 24 to locking position and causes them to snap into the sockets 25 as soon as the sections l3 have been moved outwardly.

In order to locate the several core sections more accurately with respect to each other the center section! is provided with a pair of guide pins 35 providing registering keys engageable in guide grooves 36 in the side sections III. This serves to prevent lateral shift of the several sections with respect to one another.

The gate for pouring is placed in the mold cap 8 which, as has already been stated, is divided into half sections one of which is mounted upon each of the mold sections 5 so that the cap Ii is divided and separated to free the sprue when the mold is opened. Several forms of gates may be used in accordance with this invention. The cap 6 may be provided with a single gate 31, flared at its outer end and more restricted in cross section where it enters the mold matrix. As many piston castings are provided with a reinforcing rib extending across the inside of the piston head the core sections must be provided with a groove correspondingly positioned so as to form this rib. As the piston is cast with its head up, if the gate is placed in the center of the head the molten metal must be poured directly into this groove in the core. The repeated pouring of very hot metal into this groove causes the metal to flow into the mold along the groove rather than over the head of the piston core. This tends to concentrate the flow of highly heated metal continually along one particular part of the core so that this part is liable to be overheated and tends to become corroded at the point of impact of the molten metal. In accordance with this invention the gate 31 is shifted laterally. The amount of shift need be only sufficient so that when the metal is poured into the the guide portions of the gate it will not flow directly into the center groove in the core but will miss that groove and flow over the head of the core and into the body of the piston matrix. By slightly tilting theentire machine on its trunnions 2 toward the side toward which the gate 31 is shifted the eiIect'will be to throw the incoming metal rearwardly and this helps to avoid pouring the metal into the groove in the core.

While the casting process may be carried out to advantage with only a single gate 31, this invention also contemplates providing a separate gate 38 so placed so as to enter the mold matrix close to one side thereof, This gate is used in addition to the gate 31.. As will be seen from Figure 3 the gate 38, at its inlet, is flared or extended in a radial direction with respect to the matrix so as to render it more convenient to insert the snout of the ladle in pouring the metal. As seen inFigure 4 however, which shows a bottom view of the cap 6, the gate 38 is flared or extended in a direction circumferential to the mold matrix. This enables the incoming stream of metal to spread sidewise toward both sides of the matrix. At an intermediate position between the inlet and outletends of the gate 38 its cross section is practically circular and somewhat restricted as compared with the gate 31. When both of these gates are used the gate 31 really acts as a riser. The metal i'spoured in at the gate 38 and, after filling the matrix, the surplus metal rises in the gate 31. -It will be noted that in this case the metal which rises in the gate 31 has come up from the mold and is therefore at about the same temperature as the metal of the piston headinstead of being at a high temperature such as that of the metal in the'ladle. Accordingly, the high temperature metal fresh from the ladle is held in a small gate 38 while a considerable volume of metal is held in the riser 31 but at a lower temperature. It will be seen that this arrangement enables these parts to cool down to solidification temperature much more quickly than if the entire mass of metal in the gate 31 were at the ladle temperature. Accordingly, the setting of the entire casting is hastened and the work can be carried out much more rapidly as it is not necessary for this extra volume of metal to cool down through such a great range of temperaturebefore the casting can be removed.

In order to insure that when the mold sections 5 are closed they will take position concentric with the core one or more abutments 33 are provided on the ring 1, a corresponding recess being formed upon the section 5 so that when the mold sections are closed they are positioned by engagement with the abutment 33. As these abutments are located upon the same plate in which the core sections are located the mold sections will be accurately positioned concentric with the core so that the inner surface of the oasting will be concentric with the outer surface thereof., In order to provide means for showing on the castings whether or not the mold has been accurately closed and located by the abutment 39 or whether there is an eccentricity of the exterior of the casting surface with respect to the interior thereof, the mold sections 5 are provided on the inner surface thereof with one or more prints 40 in order to form upon the casting a tell-tale impression 4|. If the mold sections 5 are properly positioned the tell-tales 4| will be equidistant from the axis of the interior bore of the casting. Accordingly, when the outer I will be unequally distant from the aids and upon turning the casting one will be removed before the other,

Figure 9, illustrates a casting 'made with the 10 mold sections improperly located so that the outer. surface is not concentric with the inner surface. The dotted lines a represent the surfhce of the cylinder to which the casting is machined.

This cylinder, which has a radius R, is concentric 16 with the axis C. The casting is usually located in the lathe by means of its inner surface having a radius RI with respect tothe axis 0. Accordingly, the cylinder A-A will be concentric with this inner surface. It will be noted that the tell- D tale 4| on the left hand side of Figure 9 is only partly cut away by the turning operation while the one on the right hand is entirely removed. Upon inspection of the turned casting the presence of only one tell-tale will indicate a defective is casting. The impression 4| may be of anydesired shape as for instance a conical impression or one of spherical form will decrease in size as it is turned off so that thedegree of eccentricity may be indicated by the size of the tell-tale re- ;o, maining.

In the operation of this machine the same may be set upright on its support I as illustrated in Figure 2 or it may be tilted on the trunnions 2. With the mold sections 5 closed and the core 3 sections in assembled relation within the mold as shown in Figure 1, the operator, by means of a suitable ladle takes a charge of molten metal from a suitable supply, and inserting the snout of the ladle into the inlet of the gate 38, pours 40 the charge of metal into the mold until the metal rises in the riser 31 as described. In case only one gate 31 is used the metal is poured in at said gate and as the latter is displaced laterally from the axis of the mold matrix, the

45 metal flows in laterally of the center of the core and flows over the top of the core and down into the lower portion of the matrix which forms the piston skirt. When the mold is full the metal rises in the gate 31 and the pouring is discon- 50 ti'nued when said gate is practically full. One operator handles two machines so that after one mold has been poured the same is allowed to stand for an interval to permit the casting to set. During that interval the other machine is 55 prepared for molding and the metal poured thereinto. By the time the second machine has been poured the casting in the first has practically set and the operator returns to it, manipulates suitable valves not shown for controlling the 60 supply of fluid pressure to the cylinders l3 and 20. Arrangements for such controls may be made as described in Patent No. 1,952,200, issued to JOhn Flammang', Percy L. Bowser and Herman Ernst, March 27, 1934. The cylinders l3 oper- 5 ate to draw apart the mold sections 5 thereby freeing the outside of the casting. The cylinder 20 withdraws the center core section 9. Upon completion of the withdrawal the head 33 depresses the cross member 3| thereby with- 70 drawing the locking pins from the side core sections as already described. As soon as the operator is satisfied that the casting has cooled to a sufficient state of hardness he moves the two handles 23 towards each other, thereby mov- 75 ing the side core sections inwardly into the space vacated by the section 9, separatingthe side sections from the interior oflthe casting and freeing the casting for removal. The casting isthen removed with a suitable pair of tongs and the fluid pressure valve manipulated to close I the mold sections and return the core section 9, the side sections I having previously been separated by means of handles 23.

When a different casting is to be made the moldsection may be changed. That is the prescut mold may be removed and a new mold mounted in the machine. In order to assure accurate positioning of the mold sections, keys 42 are provided. Each key is recessed into the mold section 5 and into its carrier 'II. If desired these keys may be permanently secured to the carriers. This provides simple means for insuring that the side sections It shall be accurateiy positioned with respect to the base and with respect to each other. M

It will be seen therefore that the invention provides a machine which may be handled rapidly in making a" large number of castings and in which automatic devices insure that the parts are accurately located so that true castings are ll insured. Undue haste on the part of the operator is also insured against by provision of theiatches 24. The gates are so arranged so as to provide ample metal therein for shrinkage and at a temperature such as to hasten cooling of the I0 casting.

, While this invention has been described as embodied in a unitary device, it will be understood that individual features and sub-combinations of this device may be useful by themselves without reference to other features or the complete combination, and that the employment of such individual features or sub-combinations is contemplate-d by this invention and within the scope of the appended claims. 40

It is further obvious that various changes may be made, within the scope of the appended claims, in the details of construction without departing from the spirit of this invention; it is understood, therefore, that the invention is not limited to 4|! the specific details shown and/0r described.

We claim: 7

1. In a piston mold of the character described having a matrix in which the piston is cast with the head up, a gate for the mold having an inlet flared radially and an outlet into the matrix flared circumferentially with respect to the matrix.

2. In a molding machine of the character described, a base, a mold thereon, a sectional core for said mold comprising center and side sections, said sections 'being constructed and arranged for withdrawal successively with a succeeding section moving into the space vacated by a preceding section, and means other than the 00 parting faces of said sections, positionable in the path of movement of the succeeding section for locking said succeeding section against movement before the preceding section has cleared said space. 66

3. in a molding machine of the character described, a base, a mold thereon, a sectional core for said mold comprising center and side sections, said sections being constructed and arranged for withdrawal successively with a suc- 70 ceeding section moving into the space vacated by a preceding section, means other than the parting faces of said sections, positionable in the path of movement of the succeeding section for locking said succeeding sectio against move- 7 ment before the preceding section has cleared said space and means operating when said preceding section has been completely withdrawn to release said locking means.

4. In a molding machine of the character described, a base, a, mold thereon, a sectional core for said mold comprising center and side sections, said sections being constructed and arranged for, withdrawal successively with a succeeding section moving into the space vacated by a preceding section, and a latch for locking said succeeding section against movement before the preceding section has cleared said space, said preceding section moving in a path to engage and release said latch when completely withdrawn.

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