US3901415A

US3901415A - Ladling apparatus

Info

Publication number: US3901415A
Application number: US422851A
Authority: US
Inventors: William Edwin Shepherd; Horace Kenneth Bridgewater
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1971-07-22
Filing date: 1973-12-07
Publication date: 1975-08-26
Anticipated expiration: 1992-08-26

Abstract

Ladling apparatus for a die casting machine includes a ladle assembly which is movable between a filling station wherein the ladle dips into a reservoir of molten metal and an emptying station wherein the molten metal is discharged from the ladle. A hydraulic, or pneumatic ram device is operable to move the ladle assembly between the filling station and the emptying station and a guide member guides the ladle assembly in its movement between the stations. The guide member and the coupling between the ladle assembly and the guide member is such that during the final portion of the movement of the ladle assembly into the emptying station the ladle assembly is tilted so as to pour the molten metal from the ladle.

Description

United States Patent 6 [191 Shepherd et al.

[451 Aug. 26, 1975 LADLING APPARATUS [75] Inventors: William Edwin Shepherd, Sheldon;

Horace Kenneth Bridgewater, Halesowen, both of England [73] Assignee: Joseph Lucas (Industries) Limited,

Birmingham, England [22] Filed: Dec. 7, 1973 [21] Appl. No.: 422,851

Related U.S. Application Data [63] Continuation of Ser. No. 274,284, July 24, 1972,

abandoned.

[30] Foreign Application Priority Data July 22, 1971 United Kingdom 34328/71 [52] U.S. Cl. 222/357 [51] Int. Cl. G011 11/10 [58] Field of Search-..... 222/357, DIG. 15, 164-166, 222/DIG. 8, 356, 358

[56] References Cited UNITED STATES PATENTS 765,552 7/1904 Bucklin 222/357 X 1,634,374 7/1927 McDonald et al. 222/357 X 2,676,370 4/1954 Doehler et al. 222/165 3,056,179 10/1962 Lorang 222/DlG. 15

Primary Examiner-Stanley H. Tollberg Attorney, Agent, or Firm-Holman & Stern [5 7] ABSTRACT Ladling apparatus for a die casting machine includes a ladle assembly which is movable between a filling station wherein the ladle dips into a reservoir of molten metal and an emptying station wherein the molten metal is discharged from the ladle. A hydraulic, or pneumatic ram device is operable to move the ladle assembly between the filling station and the emptying station and a guide member guides the ladle assembly in its movement between the stations. The guide member and the coupling between the ladle assembly and the guide member is such that during the final portion of the movement of the ladle assembly into the emptying station the ladle assembly is tilted so as to pour the molten metal from the ladle.

11 Claims, 4 Drawing Figures PATENTED M132 5 SHEET 1 OF 3 LADLING APPARATUS This invention relates to ladling apparatus for die casting machines, and is a continuation of my application 274,284 filed July 24, 1972 now abandoned.

This invention relates to ladling apparatus for die casting machines.

Ladling apparatus according to the invention includes a ladle assembly movable between a filling station wherein the ladle dips into a reservoir of molten metal, and an emptying station wherein the molten metal is discharged from the ladle, meansjoperable to move said ladle assembly between said stations, and a guide member guiding the ladle assembly in its movement between said stations, the shape of the guide member and the nature of the coupling between the ladle assembly and the guide member being such that the final part of the movement of the ladle assembly into said emptying station causes said ladle assembly to tilt so as to pour the molten metal from the ladle.

Preferably said guide member includes a pair of generally parallel rails between which the ladle is movable, each rail having a pair of guide tracks engaged by the ladle assembly, the guide tracks of one rail being substantially mirror images of the guide tracks of the other rail and the guide tracks of each rail being parallel except adjacent the emptying station where the tracks of each rail diverge in a manner to cause said tilting of the ladle assembly.

Desirably said ladle assembly includes two pairs of rollers which engage in respective guide tracks in said rails, and preferably said rails are plate-like with said tracks defined by slots in the plate-like rails.

Conveniently the ladle assembly includes a ladle and a ladle carrier, the ladle carrier engaging said guide member and the ladle being detachably engaged with the carrier.

Desirably said ladle carrier and the ladle have a sliding tongue and groove coupling affording simple and rapid engagement and disengagement of the ladle and the ladle carrier.

More preferably the ladle is in the form of a deep vessel having an aperture in a side wall between the open end of the vessel and the closed end of the vessel, the ladling apparatus being such that the ladle is dipped into the molten metal, in said filling station, sufficiently far to immerse said aperture but not said open end, the ladle filling through said aperture, and excess metal running out of the ladle through said aperture as the ladle assembly is moved from the filling station, the position of the aperture determining the quantity of metal carried by the ladle.

Conveniently the aperture in the ladle is in the form of a slot which has a lowermost edge generally horizontally disposed in use.

Desirably the ladle assembly is tilted in such a direction in the emptying station that the wall of the ladle which contains said aperture is uppermost in the tilted position of the ladle, the molten metal pouring from the open end of the ladle.

Preferably the volume of molten metal carried by the ladle is substantially that required for one shot of the die casting machine with which the apparatus is associated, and the apparatus includes a timing mechanism which controls the period of time during which the ladle remains in a tilted condition, the timing mechanism being settable to control accurately the volume of metal poured from the ladle.

Conveniently said ladle assembly is moved between said stations by a single ram, one end of which is pivotally coupled to the ladle assembly and the other end of which is pivotally coupled to a fixed member.

Preferably the apparatus includes control means linked with the die casting machine, the control means initiating movement of the ladle assembly towards the emptying station prior to closure of the dies of the die casting machine and also prior to the opening of the metal inlet of the machine injector, said control means causing the ladle assembly to halt in its movement towards the emptying station at a point close to the emptying station unless the machine dies have by then closed, and the molten metal inlet of the machine is open. I

One example of the invention is illustrated in the accompanying drawings wherein:

FIG. 1 is a diagrammatic representation of a ing machine including ladling apparatus,

FIG. 2 is a perspective view of part of the ladling apdie castparatus shown diagrammatically in FIG. 1,

FIG. 3 is a side elevational view partly in section showing the ladle of the ladling assembly in a filling station, and

FIG. 4 is a view similar to FIG. 3 showing the ladle in an emptying station.

Referrino to the drawings, the ladling assembly 11 is mounted on support bars 13 extending from the fixed frame of a die casting machine 12. The die casting machine 12 includes a fixed die 14 and a movable die 15 engageable with the die 14 to define a mould cavity. A plunger 16 is hydraulically reciprocable in an apertured sleeve 17, the sleeve 17 defining the shot well of the die casting machine and the shot well being open for filling with molten aluminum by way of an aperture 18 when the plunger 16 is in a retracted position. The shot well of the machine receives a predetermined volume of molten aluminum, and forward movement of the plunger 16 when the

dies

14, 15 are closed injects the charge of molten aluminum from the shot well into the mould cavity defined between the

dies

14, 15. The

dies

14, 15 then remainclosed for a predetermined period of time to permit the molten aluminum to solidify, whereafter the

dies

14, 15 open, the cast component is ejected, the plunger 16 is retracted in readiness for a further shot, and'the dies 14, 15 once again close.

The ladling apparatus for supplying predetermined charges of molten aluminum to the shot well of the machine 12 includes a guide member 21 defined by first and second parallel, plate like

guide rails

22, 23. The

guide rails

22, 23 are identical with one another, and each guide rail includes a pair of guide tracks indicated by the suffixes a and b respectively, the

guide tracks

22a, 22b, 23a, 23b being defined by slots in their

respective guide rails

22, 23. The

slots

22b, 23b are of greater length than the slots 22a 23a, and throughout the majority of their length the slots 22a, 22b are parallel with one another, and similarly the slots 23a, 23b, throughout the majority of their length, are parallel with one another. At the lower ends of the

guide rails

22, 23 the slots 22a, 23a terminate before the

slots

22b, 23b and at their opposite ends the slots 22a, 22b, 23a 23b are curved, the radius of curvature of the slots 22a, 23a being greater than the radius of curvature of the

slots

22b, 23b, so that at their upper ends the slots 22a, 22b diverge, and similarly the slots 23a, 23b diverge.

Positioned between the

guide rails

22, 23 is'a ladle assembly 24 including a hollow ladle 25 and a ladle carrier 26. The ladle carrier 26 includes first and second pairs of rollers disposed on opposite sides thereof respectively. The first pair of

rollers

27, 28 engage in the slots 22a 22b respectively, and similarly, the other pair of rollers engage in the slots 23a, 23b respectively. The roller 28 which engages the slot 22b and the corre sponding roller of the second pair which engages the slot 23b are both positioned on the carrier 26 at points spaced below the roller 27 and its corresponding roller of the second pair of rollers, by a distance equal to the spacing between the lower ends of the slots 22a, 23a and the lower ends of the

slots

22b, 23b. Thus when the carrier 26 is at the lower end of the

rails

22, 23 the roller 28 and its corresponding roller of the second pair engage the lower closed ends of the slots 22b. 23b while the roller 27 and its corresponding roller of the second pair engage the lower closed ends of the slots 22a, 23a respectively The carrier 26 is pivotally secured to a cross head 29 secured in turn to the free end of the piston rod 31 of an hydraulic ram 32 (FIG. 1) the carrier 26 is pivotally connected to the cross head 29 for movement about a horizontal axis extending between the

rails

22, 23 at right angles to the

rails

22, 23 and the end of the cylinder of the ram 32 remote from the rod 31 is pivotally connected for movement about a parallel axis to extensions of the

rails

22, 23.

The carrier 26 includes a pair of

side walls

33, 34 between which the upper, open end of the ladle 25 can fit. The ladle 25 is provided at its upper, open end with a pair of outwardly extending tongues 35 which engage in corresponding grooves in the inner surfaces of the

wall

33, 34. An abutment is provided extending between the

walls

33, 34 to limit the insertion of the ladle 25 between the

walls

33, 34, and a pin 36 is detachably engageable with the

walls

33, 34, to constitute an abutment resisting withdrawal of the ladle 25 from between the

walls

33, 34. Thus the ladle is engaged with the carrier 26 in such a manner that replacement of the ladle is a simple and rapid matter, the ladle being detached from the carrier merely by withdrawing the pin 36 and sliding the tongues 35 from the mating grooves in the

walls

33, 34 of the carrier.

The ladle 25 is in the form of an elongated, deep vessel of generally rectangular transverse cross section. The end of the ladle 25 remote from the carrier 26 is closed, and the open end of the ladle 25 is provided with a pouring lip 37 defined by the free edge of one of the walls of the ladle 25. The wall of the ladle opposite the wall defining the pouring lip 37 is formed intermediate the open and closed ends of the ladle with a transverse slot 38 having a lower edge 39 which is generally horizontal in use. The positioning of the edge 39 along the length of the ladle 25 determines the volume of molten metal which can be carried by the ladle. Thus a plurality of ladles of different carrying volume can be provided from a single basic form of ladle, merely by machining the slot 38 in a different position relative to the closed end of the ladle.

The operation of the apparatus is as follows.

When a cast component is ejected from the open dies of the die casting machine the component falls on to a tray from which it is subsequently collected. The component falling onto the collection tray causes closure of a micro-switch which initiates the operating cycle of the die casting machine. Thus when a component falls onto the collection tray the dies l4, 15 which are of course in an open condition are sprayed to clean the mating faces, and then the dies start to close. At this time, the ram 32 is in a fully expanded condition, and the ladle assembly 24 is at the lower end of the guide member 21. When the ladle assembly is at the lower end of the guide member the ladle 25 dips into a reservoir 41 of molten aluminum. The level of molten aluminum in the reservoir 41 is maintained in a conventional manner between upper and lower limits (indicated by dotted lines in FIG. 3) and the arrangement is such that the ladle dips into the reservoir to such an extent that the slot 38 is below the minimum level of molten metal in the reservoir, with the open end of the ladle above the maximum level of molten metal in the reservoir. Thus the ladle fills with molten metal to a point intermediate the slot 38 and the open end of the ladle, and since the slot 38 through which the ladle fills is below the surface of the molten metal then dross which forms on the surface of the molten metal will not flow into the ladle. The closure of the micro-switch by the ejection of the component onto the collection tray not only starts the cycle of the die casting machine, but also causes retraction of the piston 31 of the ram, thereby lifting the ladle assembly relative to the guide rails 22, 23. During the initial lifting movement the

rollers

27, 28 and the corresponding second pair of rollers are running in the parallel regions of their respective guide slots, and so the ladle is maintained in a vertical condi tion between the guide rails. As the ladle is withdrawn from the reservoir 41 the excess molten metal within the ladle will run back into the reservoir until the level of molten metal within the ladle is aligned with the edge 39 of the slot 38. Thereafter of course no more mq ten metal runs from the slot 38. As the ladle assembly 24 is lifted, a finger (not shown) carrying a cam moves with the ladle assembly. Shortly before the

rollers

27, 28, and the corresponding second pair of rollers engage the curved parts of their respective guide slots the cam which moves with the ladle assembly operates a micro: switch which is so connected in the control circuit of the apparatus that unless the dies 14, 15 are fully closed, and unless the plunger 16 is retracted to open the shot well, then the operation of the ram 32 will be halted, so that the ladle assembly does not move into its emptying station. The rate of movement of the ram 32 is controlled by hydraulic flow restrictors which are preset to cause movement of the ladle assembly at a predetermined rate. Thus normally the dies 14, 15 will be closed, the shot well of the die casting machine will be open before the cam operates said micro-switch, and so operation of the micro-switch will have no effect and the ladle assembly will pass through this pause point, and move onto its emptying station. However, it is desirable to provide such a pause point, since should the die spray not completely clean the faces of the dies, then the dies will not fully close, and clearly it is undesirable to inject molten aluminium into partially closed dies. Similarly, the plunger 16 may not be completely retracted owing to jamming in the sleeve 17, and it is equally undesirable to cause pouring of molten metal when the shot well which-receives the molten metal is closed.

Assuming that the dies 14, 15 are fully closed, and the plunger 16 is fully retracted, then the ladle assembly will pass through the pause point and the

rollers

27, 28 and the corresponding second pair of rollers will engage the curved regions of their respective guide slots.

The shape of the guide slots, is such that the further retraction of the piston rod 31 of the ram 32'caused the ladle assembly to tilt relative to the

rails

22, 23 so that the molten aluminum within the ladle flows towards the pouring lip 37. The slot 38 is in a wall of the ladle 25 opposite the pouring lip 37, and so of course is uppermost in the tilted condition of the ladle 25. The molten aluminum flows from the pouring lip 37 of the ladle into a heated launder 42 which is inclined, and which guides the stream of molten aluminum intothe aperture 18 in the sleeve 17, so that the molten aluminum flows into the shot well of the die casting machine. By machining the ladle 25 accurately, the quantity of molten aluminum which is delivered into the launder 42 in each cycle of operation can be accurately controlled. However, to achieve an even greater degree of accuracy a timing mechanism is incorporated into the apparatus. It will be appreciated that since the tilting movement of the ladle assembly involves a relatively small movement of the ram piston 31, then the actual tilting of the ladle into its pouring position will be relatively rapid. Immediately the

rollers

27, 28 and the second pair of rollers engage the upper, closed ends of their respective guide slots the movement of the ladle assembly is halted, by closure of a further micro-switch by said cam carriedby the ladle assembly. The further microswitch causes the flow of hydraulic fluid to the ram 32 to be stopped, so that the ram is locked in position, and further causes initiation of the timing mechanism mentioned above. The timing mechanism is set to maintain the ladle in its pouring position for a predetermined length of time which is determined by trial and error, to be the length of time necessary for the substantially exact volume of molten aluminum which is required, to pour from the ladle. When the predetermined period of time has elapsed, the timer causes hydraulic fluid to be supplied to the ram 32 in a direction to expand the ram, thereby returning the ladle from its pouring position. Thus even though the quantity of molten aluminum carried by the ladle can be accurately determined by controlled machining of the ladle, an even finer control of the amount of molten aluminum delivered is afforded by the incorporation into the apparatus of the timing mechanism. The ladle assembly is then lowered, by expansion of the ram 31 until the

rollers

27, 28 and the second pair of rollers engage the lower ends of their respective guide slots, whereupon a still further microswitch is closed by said cam to once again render the ram 32 inoperative by stopping the flow of hydraulic fluid thereto. In this position, the ladle once again dips into the reservoir 41, so that the slot 38 is below the minimum level of molten aluminum in the reservoir. The ladle assembly remains in the filling station until the initiation of a further cycle, by the ejection of a cast component from the dies of the machine onto the collection tray.

The launder 42 which receives the molten aluminum from the ladle 25 is heated along its length to prevent the molten aluminum solidifying in the launder. At its lower end, the launder is positioned above the aperture 18, and an air gap is left between the aperture 18 and the outlet of the launder whereby air and hot gases can leave the shot well of the die casting machine as molten aluminum flows into the shot well. At the end of said predetermined pouring period governed by the timing mechanism the timing mechanism, in addition to causing the ladle to 'be returned to=theg-filling station, also initiates operation of an injectiontimer of the die casting machine. The injection timer delays operation of the ram controlling the plunger 16, .to allow the molten metal to How along the length of the launder'42 and into the die cavity, whereupon the dies 14, 15 remain closed for a period of time sufficient for the charge to solidify in the die cavity, whereafter the dies 14,15

open and the cast component is ejected onto the collection tray thereby starting a further cycle of the machine. 5

It is to be noted, that the ladle assembly starts to lift towards its emptying station prior to the closure of the dies 14, 15 and retraction of lne plunger 16. In this manner, the overall operating cycle time of the die casting machine incorporating'the ladling apparatus is minimized, since clearly to holdthe ladle assembly in the filling station until the dies have closed and the plunger 16 is fully retracted unnecessarily increases the cycle time of themachine. I

Since the ladle 25 dips into molten aluminium the ladle assembly is heated by the molten aluminum-.ln order to minimize the transmission of heat to the piston rod 31' and the cylinder of the ram 32, the cross head 29 is water cooled. A supply of cooling water is pumped through passages in the cross head 29, and in addition, cooling water is also pumped through a de-. tachable brass manifold block (not shown) clamped to the cross head 29. The hydraulic supply for the ram 32 can conveniently be derived from the hydraulic supply of the die casting machine, the rate of operation of the ram 32 being controlled by a flow restrictor in the hydraulic line to the ram. A solenoid operated valve controls the direction of flow to the ram 32, to cause extension, or retraction of the ram. The ladle 25 is formed from cast iron, and is provided with a coating of a' known protective compound for minimized the chemical reaction which occurs between cast iron and molten aluminum, and which results in the corrosion of the cast iron.

We claim:

1. Ladling apparatus for a die casting machine including in combination movable ladle means; a guide structure guidingly connected to said ladle means for movement between a filling station wherein said ladle dips into a reservoir of molten metal, and an emptying station wherein molten metal is discharged from said ladle means; and drive means operatively connected to said ladle and operable to move the ladle between said stations, said drive means being connected to said ladle means by means which is never immersed in the molten metal, said guide structure including a pair of guide tracks, and said ladle means including guide track followers engaging said guide tracks respectively, said guide tracks being substantially parallel to one another except adjacent said emptying station, said guide tracks adjacent said emptying station diverging from one another and comprising ladle-tilting portions whereby, adjacent the emptying station, coaction of the guide track followers and the divergent regions of said guide tracks as said ladle means is moved, results in tilting of said ladle means to discharge molten metal from said ladle means.

2. Apparatus as claimed in claim 1 wherein said guide structure includes a pair of generally parallel, spaced guide rails between which said ladle means is movable, said pair of guide tracks being provided on one of said rails, and the other of said rails having a second pair of guide tracks which are substantially mirror images of said first mentioned pair of guide tracks which are substantially mirror images of said first mentioned pair of guide tracks.

3. Apparatus as claimed in claim 1 wherein said guide tracks are defined by respective channels, and said guide track followers are defined by rollers engaging in said channels respectively.

4. Apparatus as claimed in claim 1 wherein said ladle means comprises a ladle, and a ladle carrier, said ladle carrier engaging said guide structure by way of said guide track followers and said ladle including means detachably mounting said ladles on said ladle carrier.

5. Apparatus as claimed in claim 4 wherein the ladle carrier and the ladle have a sliding tongue and groove coupling for affording simple and rapid engagement and disengagement of the ladle and the ladle carrier.

6. Apparatus as claimed in claim 5 wherein the ladle is in the form of a deep vessel having an aperture for molten metal flow in a side wall between an open end of the vessel and a closed end of the vessel, the ladling apparatus aperture being constructed so that the ladle is dipped into the molten metal, in said filling station, sufficiently far to immerse said aperture but not said open end, the ladle fills with molten metal through said aperture, and excess metal flows out of the ladle through said aperture as the ladle assembly is moved from the filling station, whereby the position of the aperture determines the quantity of metal carried by the ladle.

7. Apparatus as claimed in claim 6 wherein the aperture in the ladle is in the form of a slot which has a lowermost edge generally transverse to the guide track and horizontally disposed when the ladle is being tilted.

8. Apparatus as claimed in claim 6 wherein the divergent guide track arrangement and followers is such that the ladle assembly is tilted in the emptying station and the wall of the ladle which contains said aperture is uppermost in the tilted position of the ladle, and the molten metal pouring from the open end of the ladle.

9. Apparatus as claimed in claim 1 wherein the ladle is such that the volume of molten metal carried by the ladle is substantially that required for one shot of a die casting machine with which the apparatus is associated, and the apparatus includes timing means which controls the period of time during which the ladle remains in a tilted condition, the timing means being settable to control accurately the volume of metal poured from the ladle.

10. Apparatus as claimed in claim 1 wherein the drive means for the ladle comprises a single ram for moving the ladle between said stations, one end of the ram being pivotally coupled to the ladle assembly and the other end of the ram being pivotally coupled to a fixed member.

11. Apparatus as claimed in claim 1 further including control means operatively connected with a die casting machine, the control means including means for initiating movement of the ladle assembly towards the emptying station prior to closure of dies of the die casting machine and also prior to the opening of a metal inlet of an injector, said control means including means for causing the ladle assembly to halt in its movement towards the emptying station at a point close to the emptying station unless the machine dies have by then closed, and the molten metal inlet of the machine is open.