US2939190A - Casting machine for casting hollow articles - Google Patents

Description

June 7, 1960 M. H. JONES ETAL 2,939,

CASTING MACHINE FOR CASTING HOLLOW ARTICLES Filed Feb. 21, 1958 5 Sheets-Sheet 1 Pig. 1

INVENTORS MERTO/V M JONES JO/IA/ PETA-'45 CASTING MACHINE FOR CASTING HOLLOW ARTICLES Filed Feb. 21, 1958 5 Sheets-Sheet 2 INVENTORS M5970 ll. JdME-S 5 Joli/V A5756 71/56? ATTORNEYS June 7, 1960 JONES ETAL 2,939,190

CASTING MACHINE FOR CASTING HOLLOW ARTICLES Filed Feb. 21, 1958 5 Sheets-Sheet 3 P15 5 INVENTOR s Alf/P70 M JO/liS' ,4 JOHN PETA-'25 7715/0 mom/5x5 June 7, 1960 M. H. JONES ETAL 2,939,190

CASTING MACHINE FOR CASTING HOLLOW ARTICLES Filed Feb. 21, 1958 5 Sheets-Sheet 4 INVENTORS M6270 fl. JONES g. Jail/V 1 572575 M, W; f Mw/JM THE/E 4770211/5 Y5 June 7, 1960 M. H. JONES EI'AL 2,939,190

CASTING MACHINE FOR CASTING HOLLOW ARTICLES Filed Feb. 21, 1958 5 Sheets-Sheet 5 S 3/ INVENTORS Mmran/ I. J0N5 5a Jd/l/V PETERS BY Q P15. 7 w P k1 THE/P ATTORAEG United States Patent CASTING MACHINE FOR CASTING HOLLOW ARTICLES Merton H. Jones, South Haven, and John Peters, Detroit,

Mich assignors to Bohn Aluminum & Brass Corporation, a corporation of Michigan Filed Feb. 21, 1958, Ser. No. 716,723

9 Claims. (Cl. 22-151) invention relates to a machine of the permanent mold type which is particularly adapted for molding hollow articles, such as pistons for use in reciprocatingpiston engines.

The present invention provides improvements on the machine shown in Patent No. 2,711,568 to Palmer, in which two mold halves reciprocate toward each other to form the outer part of the mold, and in which a plurality of core parts are moved mechanically into positions in which they form the internal core of the mold.

An important feature of the present invention resides in the fact that the mold halves are hinged for opening and closing, like a book, and engage guiding surfaces on the top of a base ring to guide the mold halves to final position with great accuracy. The underside of the base ring carries guide surfaces which form 'slideways for cooperating flat surfaces formed on the base of the side cores. In this maner all of the main movingparts of the mold are guided to their final positions by engagement with straight surfaces of the stationary base ring. These flat cooperating surfaces can be accurately machined to very close tolerances, and hence it is possible to position the moving parts of the mold with a high degree of accuracy.

The invention also provides improved means for operating the cores of the mold. Horizontal motion of the side cores is effected by bell-cranks operated by cylinders mounted at the rear of the machine to facilitate ease of adjustment and maintenance. Sometimes, when the interior space in a piston is very restricted, it is desirable to operate the machine as a drop side core type. To permit such operation when desired one of the side cores can be moved vertically by a cylinder mounted above the machine and acting through the hollow hinge post on which the mold halves are mounted. This cylinder moves the side core vertically while it is guided by guides mounted on the frame of the machine.

The center core is guided for vertical movement by cam tracks which are curved at the lower ends to permit the center core to tilt to provide clearance for the side core which is to be moved down out of the mold.

The cores which provide the openings in the piston for the wrist pins are pulled out of the mold by bell-cranks mounted on the mold halves and operated by verticallydisposed cylinders which are also mounted on the arms which carry the mold halves.

Where the piston head is of such a shape that the mold must be provided with a head cap, provision is made to mount a head cap on one of the mold halves. Vertical movement of the head cap is provided by a vertically-disposed cylinder. The head cap never leaves its register with the mold half on which it is mounted, and the vertical travel may easily be adjusted to suit the requirements of the casting.

These, and other objects and advantages of the invention will become apparent as the description proceeds.

2339,190 Patented June 7, 1960 In the drawings:

Fig. 1 is a front elevation of a machine embodying the invention.

Fig. 2 is a plan view of the machine of Fig. 1.

Fig. 3 is a side elevation of the machine as viewed from its left side.

Fig. 4 is a section on line IV-IV of Fig. 1.

Fig. 5 is a plan view of the underside of the base ring.

Figs. 6 and 7 are fragmentary sections showing mechanism for handling the drop core.

Referring to the drawings more particularly, the machine includes a frame 10 which supports a bed plate 11. The details of the machine will be described in connection with the following features.

Mold halves and their operation The two mold halves 12 and 13 (see especially Figs. 1 and 2) are formed with semi-cylindrical cavities on their meeting faces so that when these mold halves are in assembled position, they form a cylindrical cavity which defines the exterior contour of the piston casting. These the two mold halves ride across the top surface, of the bed. plate 11, and they are pivoted around the hollow hingepost 14 to form a book-type mold. Mold half 12 is. pivoted by means of mold carrier arm 15 and mold half 13 is pivoted by means of mold carrier arm 16.

piston operating in hydraulic cylinder 20.

movement of. the two mold halves 12 and 13.

7 Base ring A base ring 21 is inserted in the bed plate 11 with its upper surface flush with the surface of the bed plate. The base ring is formedwith an upstanding curb 22 which surrounds the'piston cavity. The curb 22 isforined at its rear surface, i.e. the surface facing the hinge post 14, with a flat surface 23. The lateral sides of the curb are formed with flat surfaces 24 disposed at right angles tosurface 23. The front of curb 22 is formed with 'two surfaces 25 disposed at obtuse angles to the surfaces 24. The surfaces 23, 24 and 25 serve to accurately center and position the mold halves in a manner that will now be'desciibed. 1 a

The bottom of mold half.12 carriesan attached key 26,which is adapted to fit. against" surface 23 of the curb when the mold is in closed position. Mold half 12 also carries similarkeys 27 and 28 which are adapted to engage surfaces 24 and 25 respectively when the mold is closed.

The keys 26, 27 and 28 are made of hardened steel and are' attached to the bottom of the mold half by machine screws so that these keys may be readily replaced as ,soon asthey show signs of wear. These keys project downwardly below the bottom surface of the mold half so that as the mold half slides across the bed plate, it rideson these keys.

It will be appreciated that the angular arrangement of the key 28 and surface 25 provides a draw which permits the mold half to slide easily around curb 22 to a closed position in which the hardened keys closely engage the straight surfaces of the curb, thus accurately centering and positioning the mold half 12. Similar: hardened keys are, of course, disposedon the mold half 13 so that both mold halves are accurately guided to their final molding. position. a

As shown. in Fig. 5, the undersidelofbase ringll is formed with two' downwardly extending portions 29 which cooperate to form a guideway for the side cores 30 and 31. This is done by providing thedownward portions 29 with two parallel faces '32 which are of sufiicient length to accommodate the lateral movement of the side cores and form a guideway. Each of the sidef cores! is provided witha bottom enlargement 33- which has parallel fiat faces which closely engage and are guided by the faces 32 of the guideway. It Will be understood that in assembling'the mold the side cores 30 and31 are inserted upwardly through the base ring until their guiding enlargements 33 are brought into engagement with the guiding faces:32.

It will be clear from the main movable parts of the mold are guided to .their final molding positions by cooperating flat surfaces formed respectively on the mold parts and on the base ring. These flat surfaces can, of course, be accurately machined .and therefore provide means for accurately positioning these movable parts of the mold. Since these surfaces are all formed on the basering, which is a single piece of metal, accurate positioning of these moving parts is assured, without errors due to misalignment or shifting of parts. a I

V a Core pins v The core pins 34 and '35 (Fig. 1) are adapted to be projected into the mold cavity to form the openings in the piston casting which will, in the finished piston, receive the wrist pin. Thesecore pins are reciprocated horizontally by bell-cranks 3'6 and 37 which are pivoted on the mold carrier arms and are reciprocated by piston rods 38 and 39 which in'tu'rn are moved by pistons operating in the vertical cylinders 40 and 41. Springs may be placed in. the operating linkage so that when the mold is in closed position, the core pins will be springbiased-into contact with the side cores.

The operating mechanism 'for each core pin is mounted directly on the associated mold carrier arm 'and this Yertical mounting of the operating cylinders helps to conserve horizontal space and places this mechanism where it can be easily inspected and serviced. j a

. Center core M a The entire mold and core, is of the permanent mold 7 type and the multi-part core includes the two side cores 30 and 31, previously mentioned,',and a center core 42 (see especially Figs. 1, 2, and 6).

Mechanism is provided to reciprocate this center core so as to move it down out of the mold when the core is to be removed from the casting and to push it up into the mold when the mold is to be assembled for a casting operation. This operating mechanism includes a piston rod 43 operated by a piston in cylinder 44. The rod 43 reciprocates crosshead 45 (Figs. 4mm 6). The crosshead is guided by guide pins 46 operating in vertical guide slots 47. l

The lower ends of the guide slots 47 are curved to the right as shown in Fig. '6 so that when the center core approaches the lower limit of its travel, the lower guidepins 46 ride down the outwardly curved portion of the guide slots 47, thereby tilting the upper part of .the center core to the left as seen in Fig. 6. This tilting of the center core allows room for the movement of'the righthand side core 31 a sufficient distance toward the left,

as viewed in Fig. 6, to permit complete removal of this by the hydraulic cylinder '49 (Figs. 2 m4 These.

hydraulic cylinders project rearwardly from the machine,

thereby removing these cylinders from the high temperature casting zone, and providing easy access for servicing. The operatingconnection between thenside cores and the above description that all of the hydraulic cylinders 48 2,939,190 a a a and 49is formed by bellcrank levers which are mounted below the bed plate 11. For a detailed view of these connections, see particularly Fig. 4 which is a view looking upward on the line IVIV of Fig. l. I i

As previously explained in connection with Fig. 5, each of the side cores 30 and '31 has a lower enlarged portion which is guided for horizontal movement in the guideway formed in the base ring 21 by the faces 32; The lower enlarged portion of the left-hand side core 30 is connected to an operating slide 50 which also is guided for straight-line horizontal movement and is shown in Fig. 4 in its extreme left-hand or molding position. The operating slide 50 is operatively connected to the hydraulic cylinder 48 by a bell-crank lever 51, one end of which is mounted on the frame at pivot 52. 'The bell-crank lever is connected to the piston of hydraulic cylinder 48 by means of a mushroom head 53 mounted on apiston rod reciprocating in cylinder 48. 7 The mushroom head 53 engages-in a slot 54 formed on bell-crank lever 51. The opposite end of bell-crank lever 51 extends'into a recess in the slide 50, and is provided with a slot 55 which'engages over a pin sfi mounted on the operating slide 50. t It will be-understood that as the mushroom head 53 is moved upwardly, as viewed in Fig.4, the bell-crank lever '51 will translate this motion into inward motion of operating slide '50 thereby carrying the left-hand side core 30 toward the center of the mold cavity. The operating slide '50 is retained in place by a plate 56a which is secured to bed plate 11. r V

The right-hand side core 31 is similarly mounted on an operating slide 57. Inthis case the bell-crank lever 58 is pivotallymounted .on the hollow hinge post 14 by means of the bushing 59. Hydraulic cylinder 49 operates the bell-crank lever 58 through the mushroom head 60 and corresponding slot 61, and the inner end of the bell-crank 58 is connected to the operating slide 57 bymeans ofthe slot62 andpin-63. Y I The mushroom heads 53 and 60 and their cooperating slots form detachable connections between the operating cylinders and the bell-crank levers for the side cores.

' f Drop side core Some engine pistons have enough internal clearance so that when the center core is pulled down out of the mold and the two side cores are collapsed inwardly to meeteach other at the center of thecasting, the casting mayv be removed from the side cores. However, in certain other piston designs the internal clearance is so small that it is necessary to-withdraw one of the side cores,- in addition to the center core, from the piston cavitybefore the piston can be removed. For this purpose the present machine incorporates additional mechanism for moving the right-hand side core down out of the mold cavity when such movement is desirable.

This movement is accomplished by means offthe operating cylinder 64 which projects upwardly from the: machine as seen in Figs. 1, 3, and 7. This cylinder 01)- erates a push rod '65 which is mounted within the hollow hinge post '14 and which carries the bell-crank 58 keyed to its lower end. a V V r When a piston casting having restricted internal clearance is to be cast the controls of the casting machine are set so as to cause the cylinder .64' to operate at the proper time. With this setting the core parts are manipulated by the machine asfollows: T The center core is first moved down out of the casting' to the position illustrated in Fig. 6. i The right-hand side core 31 is then moved over to-= ward the center of the casting cavity by operation'of cylinder.49 acting through bell-crank lever 58 as previously explained. At this point in the cycle the hydraulic cylinder. is operated to push the bell-crank S S downwardly.

During this downward movement the slot 61 moves down away from the mushroorn head 60,;so that the bellcrank 58 becomes disconnected from the push rod of cylinder 49. A y, l H V At the same time the bell-crank 58 engages a guide which keeps it steady during its vertical movements. The guide means includes upper and lower fingers 66 which engage on opposite sides of a vertical guide 67.

As the result of this operation the side core 31 is dropped down out of the mold to the position illustrated in Fig. 6.

At this time the left-hand side core 30 is moved over to the center of the casting cavity, and all of the core parts are now in the position illustrated in Fig. 6. The side core 30 is now the only core part in the cavity of the casting, and since this core is of relatively narrow width, the casting can now be lifted up from its cast position on the base ring.

Head cap For castings which require a removable head cap, a cylindrical cap 68 is provided (Figs. 1 and 2). This head cap is adapted to completely fill the upper end of the casting cavity and has on its lower face the necessary contour to shape the top of the piston casting. In the arrangement illustrated this head cap and its operating mechanism are mounted on the right-hand mold half 13. The operating mechanism includes hydraulic cylinder 69 connected by a piston rod 70 to the head cap 68. This head cap never leaves its register in the right-hand mold half and its vertical travel may be easily adjusted to suit the requirements of the particular casting. A compression spring is placed between the head cap and the operating cylinder 69 and provides only suflicient pressure to hold the head cap in place.

This head cap may, of course, be mounted on the other mold half if desired.

Cdntrols Suitable electrical and hydraulic controls of the general type illustrated in Patent No. 2,711,568 may be connected to the machine but since the invention is not concerned with these devices, they have not been illustrated.

Conclusion It will be understood by those skilled in the art that the machine of the present invention provides compactness, adjustability, ease of maintenance, accuracy, and interchangeability of parts to a degree not attained in any prior piston casting machine. The use of high-compression hydraulic cylinders in combination with bellcrank levers to operate mold parts reduces the length of stroke and contributes to the overall compact design.

According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

1. In a casting machine of the permanent mold type having a base ring set in a bed plate, a pair of mold halves movable across the bed plate into engagement With the base ring and into contact with surfaces formed on the base ring, the improvement which comprises: a plurality of removable keys secured to the bottom side of each mold half and projecting below the mold half to serve as shoes on which the mold halves slide, the base ring being formed with a plurality of flat vertical faces, each of said keys being formed with a flat vertical face which engages a flat face of the base ring.

2. A machine as specified in claim 1 in which the mold halves are pivoted to swing toward each other to the mold-clsing eastern, and in which the an faces of the base ring include a straight sidefacing the pivots of the mold halves, two straight sides adjacent to and at right angles with the first stfaight side, and twof'strai'ght sides arranged at obtuse angles to the second njamed s'ti aiglit'sid'es. k

3. In a "casting imminent the permanent mold type having a base ring set in a bed plate, a pair of mold halves movable relative to the base ring, and a pair of side cores movable relative to the base ring, the improvement which comprises: the base ring being formed with a guideway having straight parallel side walls, and each side core carrying a bottom enlargement formed with two fiat faces which closely engage the side walls of the guideway, whereby the side cores are guided for straight line motion in the guideway.

4. In a casting machine of the permanent mold type having a base ring set in a bed plate, a pair of mold halves movable relative to the base ring, and a pair of side cores movable relative to the base ring, the improvement which comprises: the base ring being formed on its upper side with an upstanding curb which has a plurality of fiat faces, and the mold halves being formed with fiat faces which closely engage the fiat faces of the base ring, the base ring being formed on its under side with a guideway having straight parallel sides, and each side core being formed with two fiat faces which fit in the guideway and closely engage the sides of the guideway, whereby the mold halves and the side cores are positively guided to their final molding positions by surfaces formed on the base ring.

5. A machine as specified in claim 4 in which the flat faces on the mold halves are formed on a plurality of removable keys secured to each mold half, the keys projecting down below the bottom of the mold half and serving additionally as shoes on which the mold halves slide.

6. In a casting machine of the permanent mold type: a pair of mold halves pivotally mounted on a hollow vertical hinge post, a pair of side cores which are movable toward and away from each other, each side core being mounted on a reciprocable slide, a bell-crank lever associated with each side core and pivotally mounted on the machine, each bell-crank lever having one arm operatively connected to its associated slide, the other arm of each bell-crank lever being connected to the piston rod of a hydraulic cylinder, a push rod movable vertically in said hollow hinge post, and operated by a hydraulic cylinder mounted vertically above the hinge post, the lower end of the push rod being operatively connected to the bell-crank of a side core, whereby operation of said push rod will move the side core vertically, and means for guiding said last-named side core during its vertical movement.

7. A machine as specified in claim 6 in which the connection between each bell-crank lever and its associated slide is formed by a pin-and-slot connection.

8. A machine as specified in claim 6 in which the connection between each bell-crank lever and its operating piston rod is detachable.

9. In a casting machine of the permanent mold type: a pair of mold carrier arms mounted on vertical pivots, a pair of mold halves individual to and mounted on the carrier arms to open and close in book-type action, a wrist pin core individual to each mold half and mounted to slide in an opening formed through the mold half, a bell-crank lever mounted on each of said mold carrier arms and having one end connected to its associated wrist pin core, and an operating cylinder mounted vertically on each mold carrier arm and operatively connected to one of said bell-crank levers, whereby the entire operating mechanism for each of the wrist pin cores is carried by one of the mold carrier arms.

(References on following page) References Cited .in the file of this patent UN1TEDTATES PATENTS,

8 Gayot Sept. 10, 1929 Dimeo 2 Feb. 4, 1930 Norton Och-22, 1935 Flammang 'et a1. Sept, 6, 1938 Kohl Sept. 2 1941 Kohl f -Jah. 8, 1952 Palmer June 28, 1955

Images