WO1991012104A1

WO1991012104A1 - Vertical pour casting process

Info

Publication number: WO1991012104A1
Application number: PCT/US1991/000711
Authority: WO
Inventors: Albert J. Tusek; Laimutis P. Klimas
Original assignee: Combustion Engineering, Inc.
Priority date: 1990-02-16
Filing date: 1991-02-01
Publication date: 1991-08-22

Abstract

The method comprises joining a cope (19) and drag (20) to form a mold flask (15) having a horizontal parting plane (21) which passes through a pouring cavity (39) in the flask, tilting the flask so that the parting plane is vertical and the pouring cavity is at the vertically upper end of the flask and, while the flask is vertical, pouring molten metal through the cavity to fill the flask mold. Each filled flask is maintained in the vertical orientation until the molten metal cools. After the metal cools, the flask is tilted until the parting plane is horizontal, before the cope is detached from the drag and the cast part removed. Preferably, at least two flasks are arranged on a single pallet with their parting planes oriented vertically. The preferred drag has a drag outer flange (29) and a parting line flange (37), and the cope has an outer flange (23) and a cope parting line flange (27). The parting line on the drag and the parting line on the cope include respective notches (38, 28) for defining the pouring cavity.

Description

VERTICAL POUR CASTING PROCESS

Background of the Invention

The present invention relates to foundry casting, and more particularly, to a method and apparatus for the pouring of automotive crank shafts and the like.

Automotive crank shafts are commonly manufactured by various casting processes, including the use of a cope and drag sand mold. Typically, the mold remains horizontally oriented, i.e., the drag lies flat on a pallet or conveyor and the cope is secured on the drag. The cope typically has a pouring cavity formed in the flat, upwardly facing outer wall thereof, into which the molting metal is poured. A given mold formed by a drag and cope pair can have a plurality of internally defined recesses within the sand, for forming a plurality of crank shafts within a given mold as result of a single pouring operation.

The present inventors have, through experience gained with Shell molding processes and Cosworth processes, realized that improved castings can be achieved through a vertical orientation of the mold cavity. The reason for this improvement is that slag and other impurities in the casting can be directed to a riser. In the conventional, horizontal orientation of the cavity, these impurities may be trapped in a critical portion of the crank or cam shaft.

The inventors are also aware that high pressure green sand molding provides certain advantages for the casting of crank or cam shafts, particularly dimensional stability. A further known consideration in the casting process is the desirability of retaining the casting in a strong mold for a sufficient duration to allow ample solidification and metallurgical phase transformations to occur before extracting the casting from the mold. Extending the cooling time restrains the casting during the freezing process to assure dimensional control and avoid bending and twisting tendencies of the casting.

Typical Shell molding processes are limited in production rates because of dipping and drying practice, which is time consuming. As a consequence the Shell molding process has often been restricted to high cost, low production aircraft castings, or premium casting where the quality demands are unusually high.

U.S. Patent 4,804,035 discloses a method of gravity casting crank shafts or the like, wherein the cavity defining the crank shaft is vertically oriented. Thus, the general concept of vertically casting a crank shaft is known, but the full implementation of an optimized process for vertically casting crank shafts using cope and drag molds, has not been previously been developed. Summary of the Invention

It is an object of the present invention to simultaneously achieve the advantages of high production rates and relatively low cost normally associated with high pressure molding, in conjunction with the metallurgical advantages associated with vertical pouring and long in-mold curing time.

It is a further object to provide an overall process by which the vertical pouring and extended in-mold curing time can be achieved using cope and drag type sand molds.

It is another object of the invention to provide a cope and drag type mold that is particularly adapted for use in accordance with a high production rate, vertical pouring process.

In general terms, the invention is directed to improving a conventional green sand molding system by using a flask that has modified parting line flanges on the cope and drag, opposed notches on the parting line flanges define a pouring cavity when the clamped mold is tipped up. This is in contrast to a typical mold with an integral pouring basin and a down sprue located in the cope.

The process according to the invention is typically implemented in a production line having two main loops. The first is a flask handling loop in which the cope and drag molds are made in a conventional high production manner while oriented horizontally, and the second is pour and cooling loop in which each pallet conveys at least one, and preferably two or three molds together as a mold set, to the molten metal pouring station and then through a cooling area. In this manner, a given mold can be conveyed through the pouring and cooling regions at a slower speed in the second loop than in the flask handling operations of the first loop, without diminishing overall production rates relative to standard horizontal casting processes.

Although the preferred production line has two loops as described above, from a functional point of view, the line has three areas, consisting of (1) the flask handling activities in the first loop, (2) the transfer stations wherein the molds from the first loop are rolled up 90 degrees, picked off the first loop, and placed on pallets in the second loop while the cooled, vertically oriented molds are rolled down 90 degrees from the vertical orientation in the second loop, picked off the pallets and placed onto the first loop, and (3) a casting and cooling area in the second loop, wherein the vertically oriented mold sets are poured and cured. The relatively slower conveying speed of the second loop conserves on plant space while providing sufficient cooling for enhancing the metallurgical requirements of the product. Upon completion of the slow cooling period, the flasks are again oriented in horizontal position and returned to the mold forming portion of the first loop in a conventional manner.

The present invention is particularly effective in foundries that are converting from gray iron to nodular iron, where the need for in-mold cooling is increased because of the shrinkage characteristics of nodular iron in contrast to normal grades of gray cast iron. The invention can be implemented as a retrofit to existing foundries where available space is insufficient for adequate cooling time at normal pallet conveying speeds. Brief Description of the Drawings

These and other objects and advantages of the invention will be described below with reference to the accompanying drawings, in which:

Figure 1 is a schematic elevation view of the vertical pouring of crank shafts using cope and drag molds in accordance with the invention; Figure 2 is a schematic perspective view of the upper end of a clamped mold in accordance with the invention showing the pouring cavity integrally formed at the parting line of the cope and drag;

Figure 3 is a schematic representation of a production line in accordance with the invention, showing the paths of travel of each cope, drag and mold;

Figure 4a is a schematic plan view representation of the flask handling area of the production line shown in Figure 3;

Figure 4b is a schematic plan view representation of the mold transfer areas of the production line shown in Figure 3;

Figure 4c is a schematic plan view representation of the mold pouring and curing area of the production line shown in Figure 3;

Figure 5 is an elevation view of a clamped mold adapted for use in accordance with the present invention;

Figure 6 is a plan view of the mold of Figure 5, depicted in a manner that shows portions of both the cope and drag;

Figure 7 is an elevation end view taken from the right side of Figure 5;

Figure 8 is an elevation end view taken from the left side of Figure 5;

Figure 9 is an elevation view of the mold tip up and pallet loader station as viewed along line 9-9 of Figure 4b;

Figure 10 is an elevation view of the mold tip up and pallet loading station, as viewed along line 10 in Figure 4b; Figure 11 is a schematic perspective view of the mold handling steps at the transfer station between the cooling area of the second loop and the flask handling area of the first loop, along line 11-11 of Figure 4b; and

Figure 12 is a section view of a preferred arrangement of multiple crank shafts in a given mold. Description of the Preferred Embodiment

Figure 1 shows a portion of a crank shaft casting operation 10, in which a ladle 11 containing molten metal 12 is pivotally operated to pour molten metal 12 into a mold set 13 containing one or more, preferably three, vertically oriented, side-by-side molds 14, 15 and 16. A given mold 15 contains sand which defines the shape 17 of the part to be cast. In a manner to be more fully described below, the mold set 13 is conveyed in the direction indicated by arrow 18 as part of an automated production line.

Figure 2 is a schematic, perspective view of the upper portion of a given mold (or flask) 15, the full elevation of which is indicated in Figure l. The flask is formed by a cope 19 and drag 20 secured together along a parting line or plane 21, which is vertically oriented during the mold filling operation shown in Figure 1. The cope has a solid, substantially flat face 22 and outer flange 23 extending from the cope face. The cope has relatively longer sidewalls 24 and relatively shorter end walls 25,26 which, together with the face 22, define a substantially rectangular, box-like member having an opening facing the drag 20. A parting line flange 27 surrounds the opening and is preferably of substantially identical dimension as the outer flange 23. At the upper end 25 of the cope, the parting flange 27 is notched as shown at 28. The drag 20 is substantially identical to the cope 19 with respect to the features described immediately above. Thus, the drag 20 has an outer flange 29 bordering the face 31, upper and lower end walls 32,34, opposed side walls 36, and a parting line flange 37 which abuts the parting line flange 27 of the cope along the vertically oriented parting plane 21. The parting line flange 37 of the drag 20 carries a notch 38 that is complementary to the notch 28, and together therewith forms a pouring cavity 39 through which the molten metal enters the mold 15. Optionally, an insert basin or the like 41 may fit within the pouring cavity 39.

Figure 3 is a schematic representation of a complete production line 42 having two loops 43 and 44. For convenience, loop 43 will be referred to as the horizontal handling loop, and loop 44 will be referred to as the vertical handling loop. First loop 43 may be considered to include the handling of a plurality of flask components such as the cope and drag, which are substantially horizontal before vertical re-tilting and transfer to pallets conveyed along the second loop 44. In loop 44, the mold is filled and cooled, before being horizontally re-oriented and transferred to the first loop 43, where the sequence repeats itself substantially continuously. The particular sequence of events along the first and second loops will be described below with reference to Figures 4a, b and c, which depict respectively the portions of the loops indicated in Figure 3 at 45 (the flask handling area) 46 (the transfer stations) and 47 (the pouring and cooling area) . With respect to Figure 3, the parting line 21, i.e., the parting line flange surfaces of one or both of the cope 19 and drag 20 shown in Figure 2, is represented by a solid line 48. The upper end of the mold having the pouring cavity 39, is represented by the line 49 interrupted by three dots in Figure 3. The line 51 interrupted by single dots in Figure 3, represents the top of the pallet by which the flasks are conveyed in the second loop 44.

For more easily comprehending the operations performed in the production line, the combination of the parting line 48 and a lower dash 52 represents the path of conveyance of each drag 20. Similarly, the depiction of parting line 48 with an upper dash 53 indicates the conveyance of each cope 19. Two dashes on either side of a line, such as shown in 54, indicate a clamped cope and drag, forming a flask or mold. The symbols 54,54^/ for a flask indicate either the horizontal or vertical orientation of the flask, respectively, depending on its location in the production line 42. Identifier 55 indicates a transfer station at which a horizontally oriented flask on the first loop 43 is rolled up and transferred to a pallet conveyed along the second loop 44. Similarly, 56 indicates another transfer station, at which a vertically oriented mold which has completed the cooling cycle, is then rolled down and transferred from the second loop 44 to the first loop 43. The pouring ladle is indicated by a circle at 11.

In an idealized foundry where floor space is not substantially constrained, both loops 43,44 could run at the same speed and the length of the portion of the second loop 44 in the cooling area 47 would be dictated simply by multiplying the speed of the line by the duration of the desired cooling period. As a practical atter, however, in a high production environment where upward of 10,000 crank shafts per eight hour day are cast with a cooling time of over 100 minutes each, the required floor space would be enormous.

A feature of the present invention is the ability to maintain the conveyance rate of the first loop 43 at normal for high production, i.e. at the working capacity of the mold making and handling equipment, while reducing the total length and average speed of the second loop 44 relative to that which would normally be required to keep up with the flask handling capacity of the first loop. For example, the average speed of the second loop can be less than one-half the average speed of the first loop. This is accomplished by arranging a plurality of molds, preferably three, on a single pallet so that the three molds can be handled as a set 13, as depicted in Figure 1. Thus, the throughput of the second loop 44 matches that of the first loop 43, because a mold set 13 containing multiple molds is handled as a unit in the second loop, whereas the flask components are handled individually, as is conventional, in the first loop.

Figure 4a shows the flask handling area 45 and includes conventional equipment except as otherwise indicated. At the lower left corner, a drag mold lift-off may be assumed to begin the cycle for a given one of a plurality, typically foUr to five hundred, flasks that would be continuously conveyed along the first and second loops in the preferred embodiment of the invention. Mold punch-up and plow-off equipment is provided at 102, followed by a drag roll-over at 103 and a drag roll-on conveyor with rotary parting line brush at 104. A drag molding machine, such as the SPOMATIC Model 400-HSS, is provided at 105, followed by a drag roll-off conveyor 106 and a second drag roll-over at 107. The drag 20 passes through a right angle transfer at 108 and is placed on drag transfer conveyor 109 which conveys each drag toward the ladle 11 at the pouring station (see Figures 3 and 4b) . Near the lower right corner of Figure 4a, a separator 110 detaches the cope portion 19 of a cooled mold from the drag 20, and feeds a cope mold punch-out machine 111. A cope roll-on conveyor with rotary parting line brush is provided at 112, followed by a cope molding machine 113 such as the SPOMATIC Model 400-HSS. The cope travels along cope roll-off conveyor 114 to the cope 90 degree tip-up inspection station

115. The cope is placed on the drag at the mold closer

116, the mold put on roll-out conveyor 117, and clamped at 118.

As shown in Figure 4b, the mold is further conveyed via mold right angle transfer 119 to roll-out conveyor 120. Each cope, drag and mold has, throughout the previously described path, remained horizontally oriented. At the mold roll-up and pallet loader 121 of transfer station 55, the mold is re-oriented vertically and placed side-by-side with one and preferably two other vertically oriented molds, onto a pallet conveyor 122. The pallet is loaded so that, after the right angle transfer at 123 preparatory to entering the pouring area 11 (Figure 4c) , a cope 19 is in the leading or upstream position, and a drag 20 is in the trailing or downstream position. As a pallet with mold set 13 thereon approaches the ladle 11, pallet indexer 124 is actuated to assist, along with subsequent indexes, in the proper handling of a given pallet. As shown in Figure 4c, the pallet is conveyed along pallet roller conveyor 125 adjacent to ladle 11 whereby the molten metal is poured through pouring cavity 39 at the upper end of the mold. Cooling starts immediately after the mold is full. The pallet with filled mold set 13 encounters a pallet stop 126, where it is indexed at 128 and angularly transferred at 127. Each pallet is transported along rail conveyors 129,131 and then placed in one of a plurality of pallet rail cooling conveyors 136, 137, 138 and 139, according to indexers 132, 133, 134 and 135.

An additional pallet indexer 145 is located at the feed for pallet rail conveyor 146. At pallet stop 147, each pallet is indexed 149 and redirected at right angle 148 along pallet roller conveyor 150 to stop 151 (Figure 4b) .

With reference now to Figure 4b, the pallet is further conveyed, possibly including handling by pallet transfer car 152, along pallet indexer 153 and roller conveyor 154 to pallet stop 155 at the second transfer station 56, where it is indexed at 158. At pallet stop 155, the pallet is unloaded and the mold set is rolled down and tilted 90 degrees at 157. Each mold is lifted and thus separated from the set for subsequent individual handling. The pallet undergoes a right angle transfer 156 to pallet rail conveyor 122 toward transfer station 55, where the pallet will be loaded with another flask set 13.

As shown in Figure 4a, the mold, which is now horizontally oriented, is^{^} further transported along mold return conveyor 159 to the mold unclamping station 160, where the drag mold 20 is transported along conveyor 161 to the drag mold lift-off 101, and the cope 19 is punched out at 111. Figures 5-8 show additional detail on the preferred embodiment of the cope and drag. A flask 15 is shown in a horizontal orientation with the cope 19 clamped to the drag 20. Structural elements of numeric identifiers in Figures 5-8 correspond to the numeric identifiers in Figures 1 and 2. In addition to the previously described features of the cope and drag, the cope carries in each opposed side wall 24, a pair of clamp or hook members 57 adapted to pivot around pivot point 58, substantially in parallel with the side walls. A stop 59 is provided in the cope side wall 24 for retaining each clamp 57 in the open position. A pair of clamp or latch bars 61 is provided in each side wall 36 of the drag 20, for lockingly engaging the curved portion of clamp 57. Preferably, the pivot point 58 includes a knob, boss or similar structure which can be engaged by clamping and unclamping equipment such as provided at 118 and 160 in Figure 4a.

In order to enhance the registration of the cope 19 with the drag 20 during the mold closing operation at 118 in Figure 4a, a registration bar 62 is provided in the drag end wall 36 for registry with a recess 63 in the cope lower end wall 26. Similar registry means are provided in one or both side walls, such as bars 64,66 and recesses 65,67.

As described in connection with the tilting and transfer station 55 in Figure 4b, the mold or flask 15 is re-oriented from the horizontal to the vertical position for loading on the pallet. The orientation of the flask 15 in Figure 5 is from the point of view of looking down the roll-out conveyor 120 from the right angle transfer 119, toward the mold roll-up and pallet loader 121. The roll-up of the flask depicted in Figure 5 would thus be counter-clockwise, with the ends 25,32 moving upward and to the left along a wide arc, whereas the lower end 34 of the drag 20 would rotate counter-clockwise in a-very small arc. This tilting and subsequent lift-off will be described below with reference to Figures 9 and 10. In connection therewith, a lift bar 68 and associated jaw alignment pin 69 are provided on each side wall 36 of the drag, within the channel of the drag defined by the flanges 37 and 29. After the flask is in the vertical orientation, jaws may grasp the drag 20 and lift the flask 15 for placement on a pallet. The orientation and actuation of the clamp 57 is such that the lifting of the drag 20 vertically displaces the clamp bars 61 further into the curved portion of clamps 57, with the weight of the cope 19 being transferred through the clamps 57 to the clamp bars 61. Normally, the full weight is not transferred, but rather is borne primarily by the interaction of the registration bars 62, 64 and 66 , with the respective registration recesses 63, 65 and 67.

One or more side walls 36 of the drag 20 may also carry an alignment pin 71 which extends outside the channel and mates with a recess or other structure associated with the pallet, for assuring the proper arrangement of the flasks 15 on the pallet. This will be further discussed with respect to Figures 9 and 10.

As shown in Figure 7, it is not necessary that the pouring cavity 39 be centered symmetrically with respect to the pouring ends 25 and 32 of the cope and drag. The parting line 21 passes through the pouring cavity 39, but the cavity may be located closer to one side wall or the other, particularly where each flask is sized to define an odd number, for example three, crank shafts to be formed from a single pour as is shown in Figure 12.

Figures 9 and 10 show two views of the mold tip-up and pallet loader 121. The clamped flask or mold 15A is conveyed by the conveyor 120 onto roller wheels 162 of the tip-up platform 163. The tip-up platform is supported by an arched transfer frame 165 including four vertically oriented stanchions 166 and horizontally oriented base 167 and cross beam 168. The tip-up platform 163 is horizontally oriented and rigidly connected to a vertically oriented support wing 169 which in turn is pivotally connected at 171 near the lower end of the first stanchion 166'. A tip-up piston cylinder 172 is pivotally connected at one end 173 to the tip-up platform 163 and at the other end 174 to the cross beam 168, whereby the tip-up platform may be pivoted clockwise 90 degrees, from the nine o'clock position to the twelve o'clock position. This tilts the mold 15A from a horizontal to a vertical orientation, as shown at 15A and 15B.

Since the cope portion 19A of the mold was initially clamped onto the drag portion 20A, the vertical tilting maintains the cope 19B in a relatively upstream position with respect to conveyance of the flask toward the pouring ladle. The flask in the vertical position as shown in 15B, is initially supported by the wing 169 until the lift jaws 175 grasp the lift bars 68 on the flask 15B, and carry the flask to the right, immediately over the pallet 176. The flask in the position shown at 15B need change elevation by only about two inches, as implemented by the mold lift actuator 179. The lift bar 68 may be augmented by the bar 69 which registered with a recess 181 in the jaw pads 182 to properly orient and retain the pad relative to the lift bar 68.

The pallet carries a bracket 177 having one or more recesses 178 adapted to receive the alignment pin 71 on the flask. The first flask 15C to be loaded on the pallet is carried to the right until the alignment pin 71 is immediately above the recess and then the flask is lowered onto the pallet, whereby the alignment pin and recess register. The cross beam 168 and transfer rail 183, as well as the mold lifting actuator 179, are conventional. The lift jaws shown in Figure 10 are particularly adapted to operate on the flask of the present invention. The lift bars 68 are within the envelopes of the flanges 23, 27, 29 and 37, so that the jaw pads 182 are adapted to enter the channels between flanges in order to grasp the lift bars 68.

As shown in Figure 9, the pallet is preferably loaded with three flasks or molds, forming a mold set 13 which is subsequently handled as a unitary arrangement throughout the second loop 44. The pallet 176, in a conventional manner, has wheels 184 which roll on a pallet track 185, represented by pallet rail conveyor 122 in Figure 4b.

It should be appreciated that with respect to features of the invention shown in Figures 5-10, other implementing arrangements may be possible within the scope of the present invention. For example, the movable or rotatable portions of the clamping means such as clamp 57 could be mounted on the drag rather than the cope, and the clamp latch or bar 61 or equivalent structure, mounted on the cope rather than the drag. Similarly, the lift bar 68 and alignment pin 71 could be carried by the cope, or the bars 62, 64 and 66 and associated recesses 63, 65 and 67 could be reversed as between the cope and drag. These variations are well within the ordinary skill of practitioners in this field, given the teachings of the invention as set forth in the present specification. Similarly, the tip-up and pallet loading sequence shown in Figures 9 and 10 could be implemented using equipment different from that described herein, so long as the essential features of receiving the mold 15A in the horizontal position, tipping the mold 15B • vertically so that the pouring cavity 39 is vertically at the upper end of the flask, and conveying the vertically oriented mold 15C to the pouring station, preferably in sets, is accomplished.

It should further be understood that the pallet unloader and mold roll-down shown at 157 in Figure 4b could be constructed in a manner analogous to the equipment shown in Figures 9 and 10, and operated in substantially reverse order. Figure 11 shows one possible arrangement for the station 56, in perspective such that the cured mold sets 13 are coming toward the viewer from the cooling area along conveyor 154, while oriented vertically. With the pallet at rest at the location of stop 158 (see Figure 4b) , a first jaws mechanism 186 lifts the front mold 15D from the pallet 176 and places it vertically in a generally L-shaped tip down mechansim 187, which is similar to the tip-up platform 163 and support wing 169 shown in Figure 9. The mold 15D is tilted 90 degrees backward, whereby the mold becomes horizontally oriented as shown in phantom. A second jaws mechanism 188 preferably having two pair 189,190 of opposed jaws, lifts the mold 15D and places it on the conveyor 159 of the first loop. The jaws 189,190 are sized so that they enter the channel 72 defined between the parting line flange 37 and the outer flange 29 of the drag portion of each mold. In the illustrated embodiment, the pouring cavity 39 of each mold, when in the horizontal position, is on the downstream side of the mold, and the drag portion of each mold is below the cope portion 19. In this manner, each mold set 13 is individually handled to avoid stacking the molds one on top of the other while horizontal. After a given pallet 176 has been unloaded, it is redirected along conveyor 122 toward station 55.

It should also be appreciated that both the tip-up and loading equipment 121 and the tip-down and unloading equipment 157, could be constructed so that the receiving and the discharge directions differ from those shown in Figures 4b, 9, 10 and 11. For example, in Figure 4b, it is clear that the molds approach station 55 in a direction from top to bottom on the drawing, and that after transfer to the pallets, the flasks are conveyed from bottom to top until reaching the right angle transfer 23. The pallets which pass through station 55 do not change direction along pallet rail conveyor 122.

At station 56, the molds continue along a direction from right to left as they are removed from the pallet and tipped down, whereas the pallets move from right to left until they hit stop 155, then move from bottom to top along conveyor 122. The precise path of the flasks, molds and pallets could be reversed as between the stations 55 and 56. Moreover, other arrangements are possible. The particular equipment and the timing would perhaps be more complex than that described herein with respect to the preferred embodiment, but nevertheless the fundamental features of the invention could thus be differently implemented.

Figure 12 illustrates the desirability of forming a plurality of crank shafts in a given mold or flask. The rectangular line 73 indicates the border of the opening defined by the side walls and end walls of the cope or drag. The dashed line 74 at the upper portion of the drawing indicates the extent of the associated parting line flange, and the pouring cavity 39 formed therein. The sprue 75 and associated filling channel 76 define a conduit that extends to the lower portion of the vertically oriented flask, where the molten metal is deposited in a manifold 77 or the like from which it enters each vertically oriented crank shaft mold cavity 78,79,81 from the bottom. Each crank shaft mold cavity is elongated and has a longitudinal axis, which is vertically oriented within the flask. The force of gravity on the column of metal in the sprue and channel push the molten metal up through each cavity until the cavity is filled and maintains pressure thereon during cooling.

As mentioned above, a significant advantage of the present invention is that, during cooling, the impurities in the molten metal rise to a removable bulb or the like 82 at the top of each cavity and, thus, migrate away from the lobes 83 and other lateral formations on the cam shafts.

In a typical application of the present invention, each cope and drag would have internal dimensions, of about 32x44x10 inches, and the rectangular dimension defined by the flanges would be about 42x54 inches. By using flasks in which three crank shafts can be cast with a given pour, and handling three molds as a set on a given pallet, a total of nine crank shafts are cast and cooled on a given pallet in the second loop.

The method and apparatus described above simultaneously achieves the advantages of high production and low cost associated with pressure molding, with the metallurgical advantages associated with vertical pouring and long in-mold curing time.

Claims

1. A method for the continous casting of a plurality of metal parts having a longitudinal axis, by the use of a cope and drag flask, comprising:

(a) conveying a plurality of drag molds horizontally toward a molten metal pouring station;

(b) while the drag molds are being conveyed toward the pouring station, attaching a cope mold onto each drag mold to form a plurality of horizontally oriented flasks, each flask defining an internal mold for forming the part and a horizontally oriented pouring cavity connected to the mold;

(c) before each flask reaches the pouring station, reorienting the flask vertically so that said axis is vertical and the pouring cavity is at the vertically upper end of the flask;

(d) while each flask is vertical, pouring molten metal through the cavity into the mold;

(e) maintaining each flask in the vertical orientation until the molten metal cools;

(f) after the metal cools, reorienting the flask horizontally;

(g) detaching each cope and removing each cast part from each drag; and

(h) repeating the steps (a) through (g) substantially continuously.

2. The method of claim 1 wherein, step (c) includes arranging at least two flasks vertically side by set to form a flask set, and steps (d) and (e) are performed on the flask set.

. The method of claim 2, wherein the flask sets are conveyed during step (e) at a slower average speed than the individual cope molds and drag molds are conveyed during steps (a) and (b) .

4. The method of claim 3, wherein the slower speed is about one half the average speed of conyeance during steps (a) and (b) .

5. The method of claim 2, wherein each set of flasks is carried by a respective pallet.

6. The method of claim 5, wherein the step of arranging the flasks side by side includes arranging at least two flasks in abutting relationship.

7. The method of claim 1 wherein, each flask has a parting line between the cope and drag and the pouring cavity is situated on the parting line, and step (d) includes conveying the pallet to a position such that the parting line is adjacent a molten metal pouring ladle, and operating the ladle to pour molten metal into the cavity.

8. A method for the continous casting of a plurality of metal parts by the use of a cope and drag flask, comprising:

(a) joining a cope and drag to form a mold flask having a horizontal parting plane which passes through a pouring cavity in the flask;

(b) tilting the flask so that the parting plane is vertical and the pouring cavity is at the vertically upper end of the flask;

(c) while the flask is vertical, pouring molten metal through the cavity to fill the flask mold;

(d) maintaining each filled flask in the vertical orientation until the molten metal cools; (e) after the metal cools, tilting the flask until the parting plane is horizontal;

(f) detaching the cope from the drag and removing the cast part.

9. The method of claim 8, wherein step (c) is preceded by the steps of, arranging at least two flasks on a single pallet with their parting planes oriented vertically, and conveying the pallet to a ladle containing molten metal.

10. A flask for casting a metal part, comprising: a drag including a substantially flat face and sidewalls connected to the face to form a box, the box including a drag outer flange extending from and parallel to the drag face and a parting line flange extending from the drag sidewalls at the opening and parallel to the drag outer flange; a cope including a substantially flat face and sidewalls connected to the face to form a box, the box including a cope outer flange extending from and parallel to the cope face and a cope parting line flange extending from the sidewalls at the opening and parallel to the cope outer flange; means for attaching the cope and drag together along the parting line flanges; and the parting line on the drag and the parting line on the cope including respective notch means for defining a pouring cavity into the flask.

11. The flask of claim 10, wherein, the cope and drag each have opposed, relatively longer side walls and opposed, relatively shorter end walls which define substantially rectangular boxes, respectivley, and the notch means defining the pouring cavity are formed in the parting line flanges adjacent one end wall of the cope and adjacent one end wall of the drag.

12. The flask of claim 11, including lift bar means on each side of the flask, by which the flask can be lifted and relocated while the pouring cavity is vertically oriented.

13. The flask of claim 11, wherein the means for attaching includes hook means carried by the sidewalls of one of the cope and drag and latch bar means carried by the sidewalls of the other of the cope and drag.

14. The flask of claim 13, wherein the hook means is carried by the cope and is pivotable in a plane substantially parallel to the sidewalls into engagement with the latch bar means which are fixed to the drag.

15. The flask of claim 14, including lift bar means on each side of the flask, by which the flask can be lifted and relocated while the pouring cavity is vertically oriented.

16. The flask of claim 15, wherein the lift bar means are carried by the drag along both its sidewalls, nearer the end wall having the pouring cavity than the other end wall.

17. In a production line for the casting of an elongated metal part in a mold, the improvement comprising: a plurality of molds, each formed by a flask having a cope attached to a drag along a parting plane, means within the flask defining the shape of at least one of said parts arranged so that the part longitudinal direction is substantially parallel to the parting plane, and means defining a pouring cavity into the flask along a direction substantialy parallel to the parting plane; first conveyor means on which each flask is transported while the parting plane is horizontally oriented; second conveyor means on which each flask is transported to metal pouring means while the parting plane is vertically oriented; a first transfer means for receiving the flask from the first conveyor means, tilting the flask upward so that the parting plane and pouring cavity are vertical, and placing the tilted flask on the second conveyor means.

18. The improved production line of claim 17, further including second transfer means for receiving the flask from the second conveyor means after the mold has been poured and cooled, tilting the flask downward so that the parting plane and pouring cavity are horizontal, and placing the horizontal flask on the first conveyor means.

19. The improved production line of claim 17, wherein the first transfer means includes, a generally L-shaped pivot platform for receiving a flask from the first conveyor means; means for pivoting the platform to tilt the flask upwardly; means for lifting the flask from the platform; and means for placing the lifted flask on the second conveyor means.

20. The improved production line of claim 19, wherein the first transfer means includes a frame having a cross beam; the means for lifting includes jaw means supported by the cross beam for grasping the flask, and the means for placing traverses the cross beam to horizontally displace the means for lifting.

21. The improved production line of claim 20, wherein the second conveyor means includes a pallet sized to receive a set of at least two vertically tilted flasks in side by side relation.

22. The improved production line of claim 19, wherein the second conveyor means includes a pallet sized to receive a set of at least two vertically tilted flasks in side by side relation.

23. The improved production line of claim 22, wherein the second transfer means includes, means for sequentially lifting each of said at least two flasks from the pallet, a generally L-shaped pivot platform for receiving each lifted flask from the second conveyor means; means for pivoting the platform to tilt the flask 90 degrees so that the mold parting plane is horizontal; and means for lifting the horizontal flask and placing the lifted flask on the first conveyor means.

24. The improved production line of claim 23, wherein each flask has a flange extending longitudinally and substantially parallel to the parting plane, and the means for lifting in the second transfer means includes jaw means for grasping the flange.