US1296590A - Metal-mold. - Google Patents

Description

J. H. BAMBERG.

METAL MOLD.

APPLICATKON FILED JUNE 1'. 1916.

1,296,590. Patented Mar. 4,1919.

5 SHEETS-SHEET I.

J. H. BAMBERG.

METAL MULD.

APPLICATION FILED JUNE 7, I916.

1,296,590. Patented Mar. 4, 1919.

5 $HEETS-SHEEI 2.

J. H. BAMBERG.

METAL MOLD.

APPLlCATiON FILED JUNE 1. I916.

Patented Mar. 4, 1919-.

5 SHEETS-SHEEI 3.

anuentoz (litmus J. H. BAMBERG.

METAL MOLD.

AP L N ILED JUN ,IQIE. 1,296,590. Patented Mar. 4,1919.

5 SHEETSSHEE[ 4.

J. H. BAMBERG.

METAL MOLD.

APPLICATION FILED JUNE 7, I916. 1,296,590. Patented Mar. 4,1919.

j /2 15 1a 1a 12 a 16 /6 f6 ,6 a 16 UNITED STATES PATENT OFFICE.

JOSEPH H. BAMBEBG, 0F TONAWANDA, NEW YORK, ASIGNOIB. TO THE ALUMINUM OASTINGS COMPANY, OF CLEVELAND, OHIO, A CORPORATION OF OHIO.

METAL-MOLD.

Specification of Letters ratent.

Patented Mar. 4, 1919.

To all whom it may concern:

Be it known that I, Josnrn H. BAMBERG, a citizen of the United States, residin at Tonawanda in the county of Erie and tate of'New York, have invented certain new and useful Improvements in and Relating to Metal-Molds, of which the following is a. specification.

This invention relates to molds adapted to receive molten metal or metallic alloys, such as aluminum or aluminum alloys. More particularly the invention relates to permanent molds each comprising a plurality of sections or partsconstructed and correlated to form a complete mold cavity.

One object of my invention is to rovide an improved permanent mold includlng the core, adapted for the easy and rapid casting of cup-shaped articles (such as pistons for operation within engine cylinders) which may be equipped with inwardly extending bosses, ribs, extensions, etc, and the sections of which may be so constructed and correlated that in casting, the metal will quickly flow through and to all parts of the mold cav ty, and which may be readily and quickly sep-l arated to permit the removal of the casting without damage thereto.

Other objects of my invention are to provide a sectional core tofacilitate its insertion into and ready removal from the mold cavity, the sections being readily and quickly withdrawable to free the casting and its projections, etc., by the combined lateral and axial movement of the sections relative to the asting, and these core sections and the mold body being constructed and correlated to insure control of the setting of the metal as desired throughout the castlng.

' Another object of the invention is to provide an'improved permanent mold, including a core, for casting cup-shaped articles having internally projecting bosses, ribs and extensions, or any of them, which core comprises a minimum number of relatively movable sections and is adapted to permit its ready, quick and easy removal after the cast: ing is made.

Another object of the invention is to provide an improved permanent mold, including a core, for casting cup-shaped articles having internally projecting bosses, ribs and extensions, or any of them, which core comprises a center section which may be slid longitudinally or axially relative to the casting and, at either side of the center section, a side section which surrounds an inwardly extendin boss or projection on the casting and may%:)e moved bodily substantially parallel to the axis of the bosses until it 1s free from said boss or projection, whereupon it may be drawn from the casting by longitudinal or axial movement.

Another object of m v invention is to provide an improved m0 d in which, (a) the setting of the casting will take place progressively and (b at substantially all times during the solidi cation period the ortions of the freezing metal still liquid .w1ll be in communication with a source of liquid metal, say for example in the ate, so that cavities which would normal y form by c stallization shrinkage in the casting are fil ed up.

Other objects of my invention are to provide an improved mold in which to cast a metallic alloy of the character of aluminum alloys which will produce a relativel small quantity of eutectic in the casting, an which eutectic will be caused substantially to surround the excess substance in the casting, the construction of the mold being such as to insure freedom from porosity due to crystallization shrinkage and to cause the casting to be chilled or set with suflicient rapidity to produce a relatively fine grain structure.

Another object of my invention is to provide an improved mold in which to cast a metallic alloy having a relatively low specific gravity and a relatively high coeificient of heat conductivity and in which the casting made will contain a relatively small volume of metal for the desired product and will require substantially no cleaning and a minimum amount of machining.

Another object of my invention is to provide an im roved mold in which to cast a metallic al oy, all of the walls of which mold, including core parts, which constitute the mold cavity, being shaped and disposed so that they y be easily and readily coated or treat d, in any 'well known manner, to prevent undesirable agitation of the molten metal when it flows into contact therewith, thus insuring proper setting of the metal within the mold cavity.

With these and other objects in view, the invention consists in the parts and combination or combinations of arts herein selected for the purposes of illustration and hereinafter described in the following specification and set forth in the. appended claims.

For the purpose of illustration, I have, in the accompanying drawings, shown and herein described one form of apparatus embodying my invention.

Figure 1 is a ,plan view of a mold embodymg my invention, parts of the mold being broken away.

Fig. 2 is a side elevation of the mold.

Fig. 3 is a cross-section on the line 33 of'Flg. 1.

Fig. 4 is a cross-section on the line 44 of Flg. 1.

Figs. 5, 6 and 7 are fragmentary horizontal sections on the lines 5-5, 66, and 7-7 of Fig. 4, respectively.

Fig. 8 is a view similar to Fig. 6 but showing the center core section removed and the two side sections moved horizontally to illustrate the manner of freeing the same for removal.

Fig. 9 is an elevation of the core, parts being broken away. 7

Fig. 10 is an elevation of the core, looking} toward the right orleft of Fig. 9.

ig. 11 is a bottom plan viewp the core.

Fig. 12 is a detail view of the insert for the center core section.

In the drawings, 1 indicates as an entirety a permanent mold comprising a series of members constructed to form a casting of the desired shape, such as a skirted or cupand top and bottom walls 8 tively. These walls may shaped piston for an internal combustion motor. The mold illustrated in the accompanying drawi may be formed from cast iron or other suitable material. It referably comprises a base member 2, an complementary members 3, 4, movable on the base member 2 toward and from each other. The base member 2 may comprise a platform or base plate 2, the central portion of which is suita ly surfaeed to form the bottom of the mold cavity A. The base member 2 is by preference mounted on feet or standards 2". f

Each of the complementary members 3, 4, may comprise a side wall 5, end walls 6, 7,

and 9, respecbe integrally formed, as shown in the drawings. The walls 6, 7, 8 and 9 of each member project outwardly from the rear face of the wall 5 to form aheating chamber 9", the outer side of which is formed by a plate 9 fixed in a well-known manner to the end edges of the walls 6, 7, and 8 by bolts 9'.

3, 4, indicate handles, connected in any well known manner to the plates 9 for the respective mold members 3, 4, whereby the latter can be conveniently moved to and from the operative position.

relatively thick in order that it may be capable of retaining sufficient heat to make the mold efficient for casting pistons. or other cup-shaped articles from var ous metals'and alloys, such as aluminum alloys.

At 2, the base plate 2' is provided with an annular shoulder and the bottom walls 9 of'the mold members 3, 4, are recessed at 9" to receive the shoulder 2", whereby the mold members 3, 4, are properly alined relatively to each other and also centered on the baslle plate 2 when moved together, as shown in i 1.

10 indicates auxiliary devices for alining and'centering the mold members 3, 4. The auxiliary devices 10 may be used in connection with and auxiliary to the devices-2 and 9, or as a substitute therefor. The auxiliary devices 10 preferably comprise a pair of upwardly proJecting stationary pins 10' arranged near opposite sides of the base plate 2 and recesses 10" formed in the opposing faces of the walls 5 of the mold members 3, 4. The pins 10 and recesses 10 cooperate to cause the positioning of the mold members 3, 4, at a predetermined position each time they are moved together, it being necessar to so position the members 3, 4, that their recesses 10 will receive the pins 16 to bring them face to face to form the mold cavity A.

11 indicates as an entirety a permanent sectional core adapted to removably fit within the mold cavity A. The sides of the here may be slightly tapering to facilitate its removal.

The core 11 preferably comprises a plurality of parts made of steel, thou h other suitable material may be used; in t e illustrated example it consists of a main or center section 11 having curvilinear end walls 11, and side sections 11, pne arranged at either side of the main section 11'. As shown clearly in Fig. 8, the outer wall of each side section 11 is curved, whereby it coiiperates'with the curvedwalls of the other side section 11 and main section 11 to form the inner wall of the cavity A. Each side core section 11 at either side of the center section is bodily movable horizontally, transversely of the casting after the center section 11 has been removed, as illustrated in Fig. 8, to permit its disengagement from inwardly projecting parts on the casting prior to its endwise or axial movement upwardly for withdrawal purposes. Each core section 11", 11, may be provided with a handle 11*", 11", respectively, to facilitate handling thereof in assembling and disassembling the core.

The construction of the core in sections, as herein disclosed, provides for the easy and rapid removal of the sections where the casting has inwardly extending tubular or hollow bosses, ribs or other inwardly projecting members, desired for any purpose. As shown in Figs. 9 and 10, the cavity a for each wrist pin boss is formed in the adjacent side core sections 11, by cutting away a portion of the core section wall. After the main core section 11 has been removed, the side core sections 11 are moved inwardly or horizontally toward each other, either independently or simultaneously, in order to move their lower ends from beneath the adj acent bosses of the casting in the mold cavlty, and to do this, where inwardly extending ribs are carried by the casting, without de acing or mutilating such ribs.

In the form of construction shown, I have made provision for two heat dissipating ribs which extend across the inner face of the piston head preferably at right angles to each other. Such ribs may also be used for strengthening purposes. One rib is provided for on the casting by a groove. 11 formed in and extending longitudinally of the lower end of the center core section 11"; the other rib is provided by a groove 11 formed in the lower end of the center section 11 and extending transversely to the groove 11 and by grooves 11 which aline with the groove 11 and are formed in the lower ends of the side core sections 11. \Vhere it is desired to have the transverse rib extend upwardly to the bosses, as shown in the drawings, each side core section may be formed with a groove, as indicated at 11 The opposite side faces of the main core section 11 and the inner faces or walls of the side core sections 11 are preferably fiat and surfaced for engagement with each other and to permit axial movement of the main section relative to the side sections when the sections are assembled in the mold and removed from the casting.

12 indicates devices for movably supporting the side core sections 11 on the mold members 3, 4. These devices preferably comprise flanges, one for each section, extending around the outer edges thereof. \Vhen the core sections 11' are assembled in the mold cavity A, the flanges 12 engage the top walls 8'. As the latter are flat, they permit the flanges 12 to slide thereon when the sections 11 are moved inwardly, as shown in Fig. 8, and thus guide the sections 11 bodily horizontally.

13 indicates devices, preferably flanges, secured to or formed integrally with the center section 11. These flanges extend around the curved end walls 11 of the core section 11 and rest upon the top walls 8 to support the said section in proper position.

14 indicates projecting members carried by and preferably formed integrally with the main or center core section 11. The members 14 are arranged above the flanges 13 and extend beyond their free edges so as to leave a space between each projecting member and the adjacent top wall 8. In actual practice, the core sections 11, 11, are usually wedged together very tightly within the mold opening above the cavity A. The purpose of this construction is therefore to provide devices with which a tool or lever may be engaged to pry out the center core section. I preferto providea projecting member 14 at either curved end of the core section 11".

15 indicates a pair of permanent core sections or core pins arranged to project into the mold cavity A to form openings in or through the bosses formed by the cavities a in the core sections 11. The core pins 715 preferably comprise rods, each of which extends through a pair of alined openings formed in a wall 5 and adjacent plate 9. At their inner ends the rods preferably engage the core sections 11 to limit their inward movement when positioned as shown in Figs. 1, 2 and 3. Near their inner ends, the core pins 15 may be slightly tapered to permit ready removal and disengagement from the casting. 15 indicates a collar fixed in any suitable manner to each rod 15. The collar 15 is spaced from the adjacent plate 9 to permit the use of a prying tool to be used to force the rod outwardly and remove it when necessary. Each rod 15 is provided on its outer end with a handle 15* of any suitable form.

16 indicates devices which cooperate to aline the core 11 relative to the opening in or between the mold members 3, 4, so that the inner and outer walls constituting the cavity A will be properly correlated to form the desired castings. The alining devices preferably comprise a key or rib 16 fixed to and extending longitudinally of the core section 11 and a groove 16 formed in the walls of the opening through which the core 11 is moved. The key 16 may be connected, to the core section 11 by counter-sunk screws, as shown in Fig. 4. The groove 16* may be formed by cutting away the adjoining faces of the walls 5, or bushing members 23 which will be later described.

19 indicates devices for locking the mold members together so that they may be held in rigid relationship while casting takes place. I may provide a set of locking devices at either side of the mold. Preferably,

each set of devices 19 comprises a lug or projection 19, fixed in any suitable manner to one of the mold members, such as the member 3, and a member l9 pivotally mounted on the other mold member and swingable into latching engagement with the lug 19. The member 19 carries a hook or arm 19 which engages the pin 19. The pivoted member is adapted to be driven d wnwardly against the pin 19 and the pin engaging face of the arm 19 is wedge shaped, as shown at 19, so that when the member 19 is struck with a hammer or equivalent tool, the inclined face 19 will serve to force the mold members 3, 4, tightly together and maintain them in such posi- 7 tion.

a JOIIlIIlg faces of the respectively. -Each (30111186111011 and is provided with a valve 21 In operation, the walls of the mold, including core parts, whichconstitute the walls for the mold cavity, are suitably coated or treated in any well known manner to reduce as much as ossible agitation of the molten metal as it ows'into contact therewith and to insure roper setting of the metal within themolgl cavity, as well as to protect metal of mold from action of alloy. The mold members 3, 4, are usually moved together, then the locking devices 19 are moved into operative position ready to be driven or forced into latched position and the pairs of side sections and the center of the core 11 are assembled in the mold, after which the members 19 are hammered to draw and lock the mold members together. The core pins 15, 15 are then introduced into place.

20 indicates the gate for the mold; it may be of any desired form. The gate is preferably formed by cutting away the adopposing walls 5, so that when the members 3, 4, are assembled together the cutaway portions form a gate of the desired shape. The shape and construction of the gate 20 herein shown for illustrative purposes I believe to be the sole invention of A. B. Norton, of Detroit, Michigan. As such invention forms the subject-matter of a separate application, further description of the gate herein will not be necessary.

Where the character of the castings, the mold parts and the metal poured, or either thereof, make heat the mold in carrying out the casting operation, I provide means, indicated as an entlrety at 21, for heating the mold parts or Walls to and keeping them at the desired temperatures. The heating meahs 21 may comprise suitable burners 21" to which are connected gas and air supply pipes 21 21, supply pipe has a flexible of any suitable construction. The open or free end of the burner 21' is preferably spaced from the adjolning mold member but it necessary or desirable to is arranged to project the flame into and through an opening 9 formed in the adjacent plate 9, whereby it may impinge against the wall 5 within the chamber 9". I have for illustrative purposes shown heating means 21 for each mold member 3, 4, and so arranged that the flame will impinge directlyon the portions of the adjacent wall 5 in which the gate 20 is formed. As a result of this construction, the metal flowing through the gate 20 to the mold cavity A will be kept from premature setting.

22 indicates a bracket for supporting each heating means 21. The bracket is fixed in a well known manner to one Wall of the adjacent mold member, such as the wall 7. Being connected to and movable with the mold members, the brackets maintain the burners 21 in fixed relationship to the mold members and thus permit the latter to be operated in carrying out the casting operations. T

I provide means for venting the mold cavity A to permit the ready escape of air or gases as the molten metal flows into the cavity and to effect the run of the metal to all parts of the cavity. The sectionality of the mold structure lends itself admirably to a examples is shown in Figs. 3, 4, and 5. Re-

ferring to these figures, 23 indicates an insert and 23 indicates a recess formed in the wall 5" of each mold member 3, 4, to receive an insert 23. The inserts 23 are mounted above the mold cavity "A in the opening formed by the semi-circular walls 5. They are of curvilinear shape and, as shown, form the upper walls of the opening through which the sections of the core 11 are inserted into and removed from the mold cavity A. The inserts are preferably arranged to project inwardly beyond the outer wall of the cavity A (see Fig. 3), whereby their lower ends form the upper end walls for said cavity. 23 indicates a plurality of grooves formed on the lower ends of the inserts. These grooves may extend in a direction radially relative to the axis of the mold cavity. The grooves 23 are prefer-- ably etched or otherwise formed in the surface of the ins rt so that they will be small enough to preclude molten material from flowing through them but large enough to ofthe recess 23" a channel 231 into which the outer ends of the grooves 23 lead. 23

indicates recesses or grooves formed in the outer surface of the inserts 23'. The recesses 23 extend from end to end of the inserts and in cooperation with the adjacent walls of the recesses 23 form outlets or vents leading from the channel 23 to the outside atmosphere.

23 indicates air escape grooves which may be formed on the inner surfaces of the inserts 23. The grooves 23 are connected at their upper ends with ooves 23 formed in the upper end walls 0 the inserts 23. The grooves 23 permit the escape of the air or gases from the recesses 23- which might otherwise be prevented by the flanges 12, 13, on the core sections 11*, 11, respectively, when the latter are in position. It will be noted that the vents 23 and 23 lead from the upper outer and inner corners of the cavity A. This construction permits air and other gases to escape from both of these points as the metal is poured, and insures that the metal will run into and completely fill the cavity and form a casting of the desired shape. The inserts 23 may be fixed in the recesses 23 in any suitable manner, preferably by screws, the heads of which are countersunk as shown in Fig. 5.

Another form of ventin is shown in Figs. 3, 4:, 6, 9, and 12. By t is latter form, I illustrate means for venting a cavity formed in a core section or sections. In these figures, 24 indicates an insert which fits into a recess or cutaway portion 24 in the main core section 11. This insert is of a size and shape to complete the core section, as will be readily understood from Figs. 3 and 9. On the face of the lower end of the main core section 11", opposing the inner wall of the insert 24 are formed a plurality of fine grooves 24 to permit the escape of air or gases from the cavities 11 and 11 and to insure the formation of the inwardly extending ribs on the casting. The grooves 24" lead to a conduit 24 preferably formed by cooperating grooves in adjoining faces of the insert 24 and center section 11, through which conduit the air and gases escape to lateral passageways 24, Fig. 3, between the upper end of the insert and adjacent shoulder of the center section 11 formed by chamfering or beveling the upper inner edge of the insert 24, as indicated at 24. The passagewa s 24" communicate at their outer ends wlth the vents 23.

The insert 24 is preferably fixed to the adjacent portion of the core section 11" by screws 24".

The operation of a mold embodying my invention will be readily understood by one skilled in the art. The temperature at which the parts 3, 4, and supporting structure therefor is maintained, Wlll depend largely upon the nature and character of the metal or alloy to be cast. Assuming that the burners 21 have been operated to heat up the parts of the mold to the desired temperature and that the mold complete, including core sections, is assembled, as illustrated in Figs. 1 and 2, the molten metal to be cast is brought to the mold in any suitable manner, as by a ladle and is poured into the inlet port 20 of the gate 20. It descends through the gate and enters the mold cavity A. I prefer to use a gate 20 such as illustrated in the drawings because of the peculiar advantages which it possesses in connection with the casting of a cup-shaped article having inwardly extending bosses and ribs or either of them. The construction of the gate is such that a liquid seal is formed at 20 as the metal flows through the gate. This seal after it is formed tends to preclude the passage of air and gases into the mold cavity A and also tomaterially reduce splashing of the metal within the gate during the pouring. Splashing further is substantial] .eliminated by forming the wall 20 in suc way that the metal flows smoothly along it and thence into the cavity A. Air and gases within the mold cavity escape in the wellknown manner throu h the vents provided as hereinbefore described. The metal rises from the bottom of the mold cavity upwardly until it engages with the lower end of the inserts 23, when the casting B is completed, having in this example two inwardly extending tubular bosses, b. b, and two inwardly extending ribs 5, b disposed at right angles to each other. The'weight of the metal in the upper portion of the gate serves to force the metal into the mold cavity to complete the casting, the upper end wall of the casting being substantially in line with the upper portion of the gate which directly feeds it. In addition to trapping out the air this construction of gate m actual operation serves to prevent oxids of the metals poured and other foreign materials from entering the mold cavity. Preferably, I next remove the core sections 15, 15,

by pulling endwise each of them out of the mold, or at least out of engagement with any part of the casting. Next, preferably, I ease off the lock devices somewhat and remove the main or center section 11 of the core by withdrawing it axially or longitudinally upward and away from the rest of the mold. Then by grasping the handles 11" I move bodily inwardly each of the core sections 11 so as to free it from alinement with any part of the adjacent casting boss b, see Fig. 8, and then withdraw each of the said core sections 11 axially or longitudinally from the mold. Then the mold sections 3, 4, are entirely unlatched and mdyed away from each other a sufiicient distance to permit the casting to be.

eated.

To one skilled in the art of casting metals and their alloys, the many improved mold should be others:

It will be noted that the elements of my mold construction may be so shaped and correlated as to lend themselves admirably to the making of cup-shaped castings, and particularly of cup-shaped castings like skirted pistons having inwardly extending bosses and ribs, or either of them. Each of the core sections is correlated to each of the others in such manner as to have merely a sliding or surface engagement with the adjacent section or sections; that is, none of the core sections when in operation is attached to any other core section but merely has a sliding contact or engagement therewith. Again the core sections are so shaped, disposed and correlated that they with great rapidity may be withdrawn from the casting so as to require a minimum amount of time within which all sections of the core may be removed or freed from the casting. In the casting of skirted pistons having inwardly projecting bosses this is of material advantage. The core sections 15 may be withdrawn rapidly merely by pulling them outwardly from the mold. The center section 11 may be withdrawn quickly by pullin it outwardly, longitudinally of the axis 0 the casting, and each of the sections 11 may be quickly disengaged from the casting by moving it bodily inwardly and then withdrawing it outwardly axially of the casting and the mold sections 3, 4. The mold sections 3, 4, may be then quickly unlatched and separated so as to free the casting. Where the period of time thatthe casting remains in the mold is essential in the production of the character of casting desired. my improvements will be found to be of large advantage in enabling the operator or operators to produce one after the other in rapid succession castings which have been ermitted to remain in the mold the prescribed time.

The nature and construction of the venting illustrated herein, possemes great advantage in its simplicity and efliciency and in insuring against defective castings.

It will be further noted that the elements advantages of my obvious; among of myimproved mold are so constructed as to facilitate and insure the production of cup-shaped articles such as skirted istons, having relatively thin walls and re atively thin strengthemng and radiating or heat dissipating webs or ribs, thereby reducing to a minimum the amount of metal in the case f Tt will be further noted that for the castg of skirted pistons having internally pro- Ject bosses I am enabled to dispose the be or the casting intermediate of the S88 and at one side of the casting B so as to insure substantial uniformity 0f d l' lbution of the metal from the gate with ref-- erence to each side of the casting carryin one of the bosses b, 6. My improved mol is also peculiarly adapted for controlling to advantage, as desired, the chilling 'or rate of setting of different parts of a cup-shaped casting including internal bosses and extensions. For example, I have found it desirable in. making piston castings, particularly of alloys such as above mentioned, to chill the wrist pin bosses 6 to a greater extent than any other part of the casting. To do this with my improved mold all that is necessary is to maintain the core pins 15 cooler than any other parts of the mold which come into contact with the cast metal and of sufiicient mass to insure the proper heat capacity. I have found that if the temperature of the core pins is not properly malntained imperfeet castings result. Since the volume of metal at the bosses is greater than at adjacent portions of the casting, I have found it advisable to chill these bosses to a greater extent than an other portion of the casting. Incidentally t is produces somewhat finer grain structure in the bosses which is of ad vantage in the mountin and operation of the wrist pins therein. rdinarily when the mold is in operation and the core sections removed, I have found it advantageous to apply heat to all sections of the core other than the core pins 15, and these core pins I preferably maintain at a lower temperature than the other parts of the core.

I have found that my improved mold is peculiarly adapted for use in connection with the making of castings of an alloy containing aluminum, tin, magnesium and copper,

or any combination of these metals, in that it enables me to control to advantage the arrangement of the eutectic portion of such alloy within the cast structure, it being understood that it is the composition of the alloy that determines whether or not any eutectic will be present in the casting, and it is the method of casting the alloy that determines what will be the structural relation of the eutectic to the excess substance.

I believe that progressive setting of the metal in the casting is one of the important factors in reducing porosity, and I have had in mind to have the setting take place progressively within the mold with that obJec'tin view. It is my opinion that when any period, the portions of the freezing metal still liquid are in communication with a source of liquid metal from the gate, so that cavities which would normally form by crystallization shrinkage in the casting are filled up. i

The existence of a eutectic in a metallic alloy for casting purposes is peculiarly advantageous in reducing the amount of porosity in the casting, particularly where the liquid portions of the freezing metal are in direct communication with other liquid metal, for instance in the gate, as provided by my invention, thus permitting the crystallization shrinkage within the casting to be filled up or to be taken care of from molten metal without the mold cavity proper. During the freezing of the metal in the mold cavity in my improved mold, at substantially no time is any liquid metal isolated from other liquid metal by solid portions.

It will be noted that I make the main core section 11 slightly longer than the side core sections 11, as shown in Fig. 9 and in dotted lines in Fig. 3, so that that portion of the inner surface of the cast iston head between the side core sections Wlll be slightly lower than the other portions of such surface. In the event any fins are formed on the head of the casting between the main and side core sections, this form of construction will permit the side core sections, when moved bodily inwardly for removal purposes, to readily bend over and shear ofi any finsthat may be so formed on the cast head.

It will be noted that the gate at its port of communication with the mold cavity is relatively narrow, insuring the forming of a relatively narrow section of metal between the gate and casting, which facilitates the removal of the gate from'the castingproper.

\Vhile I have shown this port of communication between the gate and the mold cavity to extend from the bottom to the top of the mold cavity, it will be understood that it does not necessarily have to extend the entire length of the mold cavity in an unbroken line so long as it does extend to the top of the mold cavity and has suflicient area between the top of the mold cavity and the bottom of the mold cavity to fill the mold cavity progressively from the bottom upwardly by continually introducing metal on top of that which has already entered the mold cavity until the top of the cavity is permanent three-part core insertl finally reached.

To those skilled in the art many modifications of and widely differing embodiments and applications of my invention will suggest themselves, without de arting from the spirit and scope thereof. y disclosures and the descriptions herein are purely-illustrative and are not intended to be in any sense limiting. v

What I claim is:

1. In a mold for casting pistons, the combination of a permanent mold body having an opening, the walls of which form the outer walls of a mold cavity for a piston casting having a head and a skirt, and a permanent three part core insertible within said body to form the inner walls of the cavity, the said core comprising a center section, the opposite end walls of which are shaped to form parts of the inner wall of the mold cavity, and a section arranged at either side of the center section having an outer wall in which is formed between its opposite longitudinal ends a boss cavity.

2. In a mold for casting pistons, the combination of a permanent mold body having an opening, the walls of which form the outer walls of a mold cavity for a piston casting having a head and a skirt, and a permanent three part core insertible within said body to form the inner walls of the cavity, the said core comprising a removable center section, the opposite end walls of which are shaped to form parts of the inner wall of the mold cavity, and a section arranged at either side of the center section having an outer wall in which is formed between its opposite longitudinal ends a boss cavity, said side sections being movable bodily inwardly after the removal of the center core section and then withdrawable longitudinally.

3. In a mold for casting pistons, the combination of a permanent mold body having an opening, the walls of which form the outer walls of a mold cavity for a piston casting having a head and a skirt, a permanent three part core insertible within said body to form the inner walls of the cavity, the said core comprising a center section the opposite end walls of which are shaped to form parts of the inner wall of the mold cavity and a section arranged at either side of the center section havin an outer wall in which is formed between its opposite longitudinal ends a boss cavity, and means for mo'vably supporting said side sections on said mold body. 7

4. In a mold for casting pistons, the combination of a permanent mold body having an opening the walls of which form the outer walls of a mold cavity for a piston casting having a head and a skirt and also form elon ated cylindrical core-supporting walls outside the mold cavity pro er, and a Ele within the mold body to form the inner walls of the cavity, the said core comprising a center section and two sections arranged, respectively, on op osite sides of the center section, each 0 said sections constituting in itself a rigid body and the center section having curved walls adapted to engage and fit the aforesaid elongated core-supporting walls at diametrically opposite points and the said side sections having curved outer walls which also engage and fit the said coresupporting walls, whereby the mold sections, when assembled in the core body, are rigidly supported thereon with their free ends spaced'from the outer walls of the cavity.

5. In a mold for casting pistons, the combination of a ermanent mold bod having an opening, tlie walls of which orm the outer walls of a trunk piston mold cavity, and a three part core comprising a center section and a section arranged at either side thereof, each side section having in its outer wall a central recess to form an internal projecting member on the piston.

6. In a mold for casting pistons the combination of a ermanent mold bod having an opening, tie walls of which orm the outer walls of a trunk piston mold cavity, a core comprising a center section and a section arranged at either side thereof, each side section formed in its outer wall with a central recess, and core pins insertible through openings in the mold and cooperating with the walls of the recesses in the side core sections to form internally projecting hollow wrist pin supports on the piston casting.

7. In a mold for casting pistons, the combination of a permanent base member, a pair of permanent mold members movably mounted on said base member and cooperable therewith to form the outer walls of a piston mold cavity, and a permanent core comprising a pair of spaced side sections having alined boss cavities and a center section arranged between and slidably engaging the side sections, the outer walls of said sections being suitably formed and coiipen' ating to form the inner walls of the mold cavity.

8. In amold for casting pistons, the combination of a permanent mold body having an opening to form the outer walls of a piston mold cavity, a permanent core, comprising a center section and a section arranged at either side thereof, the outer walls of said sections being suitably formed and cooperating to form the inner walls of the mold cavity, and means for slidably supporting the side sections at points outside of the mold cavity and permitting them to be moved inwardly transversely of the casting.

9. In a mold for casting pistons, the combination of a permanent mold body having an opening to form the outer walls of a piston mold cavity, a permanent core, comprising a center section and a section arranged at either side thereof, the outer walls of said sections being suitably formed and cooperating to form the inner walls of the mold cavity, and means, extending from one end of each of said side sections for slidably supporting the side section and permittin it to be moved inwardly transversel o the casting.

10. n a mold for casting pistons, the combination of a permanent mold body having an opening to form the outer walls of a cavity, and a ermanent core comprising a removable mam section and a separate section arranged at either side of said main section, each side section having a recess formed in its outer wall between its oppo site longitudinal edges, and core pins extending into said recemes and cooperating therewlth to form hollow'wrist pin supports.

11. In a mold for. casting pistons, the combination of a permanent base member, a pair of permanent mold members movably supported on said base member and cotiperable therewith to form the outer wall of a cavity, and a permanent core comprising a removable main section and a separate section arranged at either side of said main section, sai main section extending across said cavity with its longitudinal axis coincident with the axis of saidcavity, the opposite end walls of said main section being curved and the outer walls of said side sections being curved and coiiperating with the end walls of said main section to form the inner curved wall of the cavity.

12. In a mold for casting pistons, the combination of a permanent base member, a pair of permanent mold members movably supported on said base member and cooperable therewith to form the outer walls of a cavity, and a permanent core comprising three sections arranged side by side and having flat abutting walls slidably engaging each other, the opposite end walls of the center section being curved and the outer walls of the two side sections being curved and cooperating with the curved end walls of the center section to form the inner curved wall of the cavit 13. The combination of a permanent mold body forming the outer walls of a cavity, and a permanent core comprising three sections arranged side by side and slidably engaging each other, whereby the center section can be removed to permit movement of said side sections toward each other, the end walls of the center ection and the outer walls of the side sections being curved and 006 eratin to form the inner wall of the cavity, an the outer curved wall of each side section bein tween its opposite longitudinal edges.

14. The combination of a permanent mold body forming the outer wall of a cavity, a permanent core comprising three sections arranged side by side and slidably engaging each other, whereby the center section can be removed to permit movement of said side sections toward each other, the exposed 110- formed with a recess be walls of said sections being curved and cooperating to form the inner wall of the cavit and the outer wall of each side section eing formed with a recess, and core pins coiiperatin with the Walls of the recesses to form ollow wrist pin bosses on the casting.

15. In a mold for a skirted piston casting, the combination of permanent bottom and side walls forming the outer walls of the cavity, a permanent core forming the inner walls of the cavity, and comprising three separate sections arran ed side by side and each slidably engaging the adjacent section or sections, the center section bein movable endwise inde endently of the side sections and each si e section being movable laterall and then endwise, and core pins insertib e through openings in the side walls of the mold and arran to engage the outer walls of said core side sections.

In testimony whereof I afiix my ignature, in the presence of a witness.

JOSEPH H. BAMBERG.

Witness Gm. B. Prrrs.

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