GB1601549A

GB1601549A - Automatic casting apparatus

Info

Publication number: GB1601549A
Application number: GB2533578A
Authority: GB
Original assignee: Associated Engineering Italy SpA
Current assignee: Associated Engineering Italy SpA
Priority date: 1978-05-31
Filing date: 1978-05-31
Publication date: 1981-10-28

Description

(54) AUTOMATIC CASTING APPARATUS (71) We, ASSOCIATED ENGINEER ING ITALY S.P.A., an Italian Company, of Strada Valdellatore, 10091 Alpignano, Turin, Italy, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to apparatus for the automatic transport of molten metal from a furnace to a casting die or mould, and to ladles for this purpose. Reference is made to Patent Application No. 8025784 (Serial No. 1,601,550) divided out of this application.

Various apparatus of this kind is known. For example, British Patent Specification 1,420,898 (Italpresse) describes apparatus having a fixed frame (not pivotable) with an arm passing above the furnace and die, a carriage movable along the arm, two vertical bars carried by the carriage and movable one with respect to the other, and a ladle hinged on the lower ends of the bars in such a manner as to be rotatable about a horizontal axis. The two bars are operated independently by separate electric motors.

The tilting of the ladle about an axis adjacent to its lip is known (Foundary: November 1972: page 53-Fig. 3).

A machine in which an automatic ladle unit serves two die-casting machines from a holding furnace is known (Machinery & Production Engineering: 24 April 1974: page 505-Figs. 4 & 5) but the known machine has only about half the production rate of the present machine in the version having two sets of arms, as the known machine has only a single arm and ladle.

A machine of swinging arm design is known, in which the position of the ladle is controlled by chain and sprocket drives (Machinery & Production Engineering: 28 August 1974: page 254-Fig. 10). United States Patent No. 4,061,179 discloses casting apparatus including a vertical column mounted for rotation about a vertical axis and a cantilever mounted at one end on the column for rotation about a horizontal axis; however, the angle of the ladle is not determined by a cam, and moreover the ladle is of the kind having a bottom outlet opened and closed by a plug, rather than having a pouring lip.

French patent publication No. 2,273,613 (Patent No. 74 19422) discloses an automatic pouring ladle which is overturned, but this depends on the movement of an arm in a vertical plane through the vertical position, rather than on a cam device.

Russian Authors Certificate No. 474,398 discloses apparatus for the transport of molten metal from a furnace to a casting die, which includes a guide cam cooperating with a bracket on the ladle to control the position of the ladle as it is withdrawn from the melt, to meter the amount of metal in the ladle so that, during transport, the level is not determined by the filling orifice, thus reducing the risk of spillage. However, after withdrawal from the melt, the ladle ceases to be controlled by the guide cam. Moreover, the lever carrying the ladle moves solely in a vertical plane.

British Patent No. 1,381,647 (Chrysler Corporation) discloses a pouring apparatus for charging a mould with molten metal. This apparatus includes a ladle carried at one end of a horizontal arm, the other end of which is mounted on a support, about which the arm is radially movable in arcuate sweeping fashion; the arm is rotatable about its longitudinal axis by means of a com follower fitted on the arm and co-operating with a motor-driven cam for rotating the member about its horizontal axis, so that the ladle can be tilted between one attitude, in which it is substantially horizontal for filling with metal from metering means, and another attitude in which it is tilted for pouring.

It will be noted that the arm is attached to the ladle at a single point; that molten metal is metered into the ladle from above, rather than by dipping of the ladle in the molten metal; and that the ladle is therefore horizontal during filling, rather than having the end farthest from the pouring lip lowermost.

According to the present invention, therefore, apparatus for the automatic transport of molten metal from a furnace to a casting die or mould includes cam means which automagically control the position of the ladle in the vertical plane throughout the cycle of operation, wherein the cam means includes means automatically to overturn the ladle after pouring, whereby to knock out any metal or oxide remaining therein.

According to a feature of the invention, apparatus for the automatic transport of molten metal from a furnace to a casting die or mould includes arm means mounted on a pillar pivotable about a vertical or substantially vertical axis so that the free end of said arm means moves in a generallyhorizontal part-circular arc around said pillar, a ladle supported from said free end to be pivotable about a substantially horizontal axis passing through or near its pouring lip, and means connected to said ladle at a point spaced from said axis to cause it to pivot about said axis, said last-mentioned means being operated by motor-driven cam means.

According to another aspect of the present invention, apparatus for the automatic transport of molten metal from a furnace to a casting die or mould includes a rotatable column arranged to rotate about a substantially vertical axis, a pair of arms jointed to the column, and arranged to rotate about a substantially horizontal axis, a first member parallel to the column and jointed to the outer ends of the arms so as to form a parallel motion linkage, a ladle joined to said first member at a first point on the ladle, a second member movable relative to the first member and joined to the ladle at a second point spaced from the first point, so that movement of said second member causes pivoting of the ladle around said first point, and motordriven cam means arranged to control movement of said second member, said members and said cam means being so arranged as to overturn the ladle after pouring, whereby to knock out any metal or oxide remaining therein.

An embodiment of the automatic pouring machine, with certain alternatives, will now be described with reference to the accompanying drawings, of which: Fig. 1 is an elevation of the machine, also indicating one alternative form using two sets of arms, Fig. 2 is a plan view, partly in section, of the machine of Fig. 1, Fig. 3 is a partial elevation, similar to Fig.

1, but showing the machine in a different position, Fig. 4 is a section on the line IV-IV of Fig. 1, Fig. 5 is a section on the line V-V of Fig. 4, Fig. 6 is a section on the line VI-VI of Fig. 1, Figs. 7 (a) to (e) are diagrams showing relative positions of the ladle and of the pouring cam, looking in the direction of arrow VII in Fig. 2, Figs. 8 (a) to (e) are diagrams showing the relative positions of the ladle and the over turning cam, looking in the direction of arrow VIII in Fig. 2, Fig. 9 is a view on a large scale of a ladle having a single pouring lip, on the section IX-IX of Fig. 10.

Fig. 10 is a plan view of the ladle of Fig. 9, Fig. 11 is a view on a larger scale of a ladle having a double pouring lip, on the section XI-XI of Fig. 12, Fig. 12 is a plan view of the ladle of Fig.

11, and Fig. 13 is a plan view of a layout of the automatic pouring machine, furnace, and die casting machines.

Referring to the drawing, in particular Figs. 1-3 and 13, the automatic pouring machine 10 is for the purpose of filling a ladle 11 from a holding furnace 12 for molten metal, transporting the ladle to a die casting machine 13, and pouring the molten metal from the ladle into the die cavity of the die-casting machine.

The pouring machine 10 has a base 14 in the form of a rectanguar cabinet, in the upper surface 15 of which is mounted the stationary member 16 of a pillar 17, which can be rotated relative to the stationary member.

Two pairs of radial arms, an upper pair 18a, 1 8b and a lower pair 19a, 19b, are pivoted to the pillar 17, respectively by an upper pivot pin 20 and a lower pivot pin 21, vertically above one another. The outer ends of the radial arms 18a, 18b, 19a, 19b are pivoted to vertical members 22a, 22b by an upper pivot pin 23 and a lower pivot pin 24, the same distance apart as pins 20, 21, thus forming a parallelogram linkage. The lower ends of members 22a, 22b, are pivoted to a member 71 rigidly connected to the ladle 11 close to its pouring lip 25, so that the ladle can rotate about the horizontal pivot axis 25a.

A second, identical, apparatus may be mounted on a concentric column 17', and is indicated by dashed numerals, e.g. 18a' etc.

The ladle 11 is shown in Fig. 2 as having two pouring lips 25 to accommodate two appropriately spaced die cavities simul taneously, but clearly there could be one lip or any convenient number. The upper central region of the ladle is connected by a pivot pin 26 to a member 27 inclined to the vertical. The upper end of member 27 has a cam-follower 28 which cooperates with cams 29, 29a, the rotation of the cams 29, 29a thus regulating the inclination of the ladle 11. Moreover, the rotatable shaft 30 to which cam 29 is secured passes with a small clearance through an elongated slot 31 near the upper end of the member 27, guiding the member to travel substantially in the direction of its length. Cam 29a is mounted on a separate shaft 30a, concentric with shaft 30, to be rotatable independently of cam 29, under control of a motor 56a mounted on arm 18a.

To move the parts of the pouring machine in the necessary manner, the following mechanisms are provided.

In order to rotate the pillar 17 and radial arms from the position in which the ladle 11 can be lowered into the holding furnace 12 to the position in which the metal can be poured from the ladle into the diecasting machine 13, there is provided (Fig. 4) an electric motor 32 mounted from a side wall of the base 14, and driving through a reduction gear 33 two gearwheels 34, 35 rotating on the same shaft about a vertical axis. The gearwheels 34, 35 drive respective gearwheels 36, 37 (Figs. 4 & 5) at the lower end of vertical shafts 38, 39 mounted in the upper horizontal member of cabinet 14.

Each shaft 38, 39 has a radius arm 40, 41 (Figs. 1, 4 & 6) at its upper end (one arm 40 being above the other 41) operating respective racks 42, 43 which in turn mesh with pinions 44, 45 on the rotatable pillar 17. Rollers 46, 47 mounted on surface 15 maintain the racks 42, 43 in mesh with the respective pinions.

In this way, by operation of motor 32, the radial arms 18, 19 can be moved through a right angle. Where a second set of arms is mounted on concentric column 17', this may be driven in a similar way.

The angle of the radial arms 18, 19 (and 18', 19', if present) to the vertical is controlled by a motor 48 mounted on the end of the arms 18, 19 remote from the ladle 11.

The motor 48 drives through a reduction gear 49 a radial arm 50 having at its free end a pin 51 which cooperates with a slot 52 in an arm 53 secured to the rotatable pillar 17. It will be clear that if the arm 50 is rotated in the clockwise sense, the radial arms 18, 19 will also be rotated in the clockwise sense about their pivots 20, 21.

A further motor 56 mounted on the rotatable pillar 17 drives through reduction gearing 57, universal joint 58, shaft 59 and universal joint 60, a further reduction gear 61, which drives shaft 30. Thus the position of cam 29 is determined by the rotation of motor 56.

The ladle 11 itself is approximately crescent shaped in plan view (Figs. 2 & 12) to provide the pouring lips 25 at each end of pivot axis 25a, and has a filling port 64 in the plane midway between the pouring lips. The port, which is best seen in the vertical section (Figs. 1 & 11), is formed by two parallel walls 65, 66, which are vertical as seen in the figure. The inner wall 65, which forms part of the bowl-shaped peripheral wall of the ladle, has an outward projection 67 at its base, the projection being at right angles to the parallel walls 65, 66 and extending to just beyond the plane of the outer wall 66. There is a gap between the base of the outer wall 66 and the projection 67 to form port 64. The outer wall 66 is higher than the inner wall 65.

In operation, the machine starts in a holding position, in which the ladle 11 is above the holding furnace 12 and heated by it; motor 56 has been operated to rotate pouring cam 29 so that the cam follower 28 moves to the smallest radius from the axis of rotation of the pouring cam 29, member 27 has moved down, and ladle 11 has rotated so that, since the pouring lip 25 is supported by members 22a, 22b, the projection 67 is the lowest point of the ladle, as seen in Fig.

7(a).

Motor 48 is then operated to rotate radial arms 18, 19 about pivots 20, 21, lowering the ladle 11 into the molten metal (Fig. 3).

Suitable probes are provided on the ladle, which stop the motor and thus control the depth of immersion. As the ladle enters the molten metal, projection 67 traps the surface skin of oxide, and pure metal from below the surface passes through the port 64 be tween wall 66 and projection 67, up between the walls 65, 66 and over the lower, inner wall 65. Provision is made for automatic adjustment to compensate for variation in the level of the molten metal from an upper level 68 to a lower level 69. (In practice the ladle would never reach the completely immersed position shown).

The ladle 11 is then rotated about its pivot axis 25a, by operation of motor 56 driving pouring cam 29, until walls 65, 66 are vertical, as seen in Fig. 7b, and then the ladle is raised by operation of motor 48 pivoting arms 18, 19.

Operation of motor 32 rotates pillar 17 until the ladle has moved in an arc of a circle to be correctly positioned above the die casting machine; further operation of motor 56 then rotates the pouring cam 29, causing the ladle 11 to rotate slowly about its pivot axis 25a in a direction to pour the molten metal from the two lips 25 into the two die cavities (Fig. 7c) of the die-casting machine 13.

When pouring is completed, the cam follower 28 moves back onto a smaller radius part of cam 29, to position the ladle as in Fig. 7(d), while the radial arms 18, 19 are being transversed back from the diecasting machine 13 towards the holding furnace 12. At this stage motor 56a drives overturning cam 29a, through shaft 30a, rapidly through two complete revolutions.

Starting from the position of the ladle shown in Fig. 8(a), the overturning cam 29a is driven so that the cam follower 28 moves over a gradually increasing radius, to the point shown in Fig. 8(b), followed by a sharp decrease in radius (Fig. 8c). This causes the ladle 11 to pivot about its axis 25a until the end 66 remote from the lip 25 approaches or passes through a position vertically above the axis 25a (Fig. 8(b)). The cam follower 28 then moves over the part of the sharply decreasing radius (Fig. 8(c)) so that the ladle 11 continues to an inverted position owing to its momentum. This movement of the ladle is sharply checked by the arrival of the cam follower 28 on the part of the cam 29a of smaller radius, so that any remaining metal or oxide in the ladle is knocked out. Further rotation of cam 29a in the same direction causes the cam follower 28 to move for the second time over the part of the cam 29a of gradually increasing radius, (Fig. 8(d)) thus causing the ladle 11 to pivot about its axis 25a in the opposite sense of rotation until the end 66 remote from the lip 25 approaches or passes through a position vertically above the axis 25a, the cam follower 28 then moving for the second time over the part of sharply decreasing radius so that the ladle 11 continues, due to its momentum, back to its original non-inverted position (Fig. 8(e)).

It will be understood that this rotation of cam 29a takes place while the arms 18, 19 are traversing from the die-casting machine 13 back towards the furnace 12, and while the other cam 29 is in the position shown in Fig. 7(e). Thus during rotation of cam 29a to cause overturning and knockout of the ladle, the cam follower 28 lifts off cam 29. Moreover, as cam 29a only rotates when cam 29 is in this position, and returns to a position of rest shown in Figs. 8(a) and 8(e) with the cam follower on the small radius part of cam 29a, it does not interfere with the movement of cam follower 28 under the control of cam 29 during the remainder of each filling and pouring cycle. It will be clear that cam 29a rotates for a much shorter time than cam 29.

After being overturned, the ladle 11 returns to the holding position of Fig. 7(a), the cycle time normally being determined by the time for the molten metal to solidify in the die-casting machine 13, and to be ejected from it.

There is shown in Figs. 9 and 10 a form of ladle 11' having a single pouring spout 25'. In other respects this ladle 11' is the same as ladle 11 shown in Figs. 1-3, 7 and 8, and in greater detail in Figs. 11 and 12.

It will be understood that vertical members 22a, 22b are pivoted to members 71 which are fixed with respect to the ladle 11, rather than to the pouring lip 25 itself. Moreover the ladle 11 with two pouring lips 25 may have a central dividing wall 70 to ensure that an equal amount of metal is poured from each lip 25.

The automatic operation of the machine is controlled automatically as follows. The first cycle is started by energising motor 48 by means of a push-button switch, subsequent cycles being started automatically. This causes the arms 18, 19 to be lowered rapidly to a "holding" position with the ladle over the molten metal. On receiving a signal from the die-casting machine that it is ready, a microswitch causes the ladle to descend at a reduced speed, and next the temperaturesensitive probes stop the ladle in the filling position. After a suitable interval motor 48 starts to raise the ladle slowly. When the ladle reaches the "holding" position again, operation of a micro-switch causes motor 48 to raise the arms 18, 19 rapidly and stop in their uppermost position, and at the same time causes motor 56, through cam 29, to rotate the ladle to the horizontal position.

Operation of a micro-switch as the arms reach their uppermost position stops motors 48 and 56, and energises motor 32 to rotate pillar(s) 17 and traverse the arms towards the die-casting machine. On reaching the pouring position, a micro-switch positioned on surface 15 and operated by a projection on pillar 17 stops motor 32, and energises motor 56 to tilt the ladle, thus pouring the metal. When the ladle is fully tilted, a further micro-switch is energised to stop motor 56 and start motor 32 to start traversing the arms back to the furnace. Moreover, after a short interval, motor 56 operates to move the ladle from the pouring position Fig. 7(c) towards the holding position Fig. 7(e). As the ladle reaches this position, a further microswitch energises motor 56a to overturn the ladle (Fig. 8); when the ladle is returned to its normal (holding) position Fig. 8(e), a further micro-switch is operated, and when this and yet another micro-switch which is operated when the arms have traversed back to a position over the furnace, have both operated, the cycle is ready to begin again.

A plan view of one layout is shown in Fig. 13. The automatic pouring machine 10 has two sets of arms, one set 18a, 18b, 19a, 19b supporting a ladle 11, and a second set 18a', 18b', 19a', 19b' supporting a ladle 11'. Two holding furnaces 12A, 12B, are shown, of which only one may be in use at any given time, while the other is being refilled. The holding furnaces may be on a turntable 72, so that in one position of the turntable one furnace, say 12A, may be in a position in which the ladles 11, 11' can be filled from it, while furnace 12B is filled, and vice versa.

In Fig. 13, ladle 11, when filled as described above, transports metal to and pours it into the die cavities of die-casting machine 13A, and ladle 11' pours metal into machine 13B. The sequence of operations will be arranged so that, for example, ladle 11 is filling in the furnace while ladle 11' is pouring, and vice versa.

WHAT WE CLAIM IS:- 1. Apparatus for the automatic transport of molten metal from a furnace to a casting die or mould, including cam means which automatically control the position of the ladle in the vertical plane throughout the cycle of operation, wherein the cam means includes means automatically to overturn the ladle after pouring, whereby to knock out any metal or oxide remaining therein.

2. Apparatus as claimed in claim 1 for the automatic transport of molten metal from a furnace to a casting die or mould, including arm means mounted on a pillar pivotable about a vertical or substantially vertical axis so that the free end of said arm means moves in a generally-horizontal part-circular arc around said pillar, a ladle supported from said free end to be pivotable about a substantially horizontal axis passing through or near its pouring lip, and means connected to said ladle at a point spaced from said axis to cause it to pivot about said axis, said last-mentioned means being operated by motor-driven cam means.

3. Apparatus as claimed in claim 2, wherein said motor-driven cam means includes a cam, and said means connected to said ladle includes a member connected to the ladle at said point, an having cam follower means remote from the ladle and co-operating with the cam, the cam being so shaped and driven that in a first, filling, position the end of the ladle remote from the pouring lip is lowermost; in a second, traversing, position the ladle is substantially horizontal; and in a third, pouring, position the ladle is pivoted so that its pouring lip is lowermost.

4. Apparatus as claimed in any preceding claim, wherein said cam means includes adjacent first and second motor-driven cam means, said second cam means co-operating with cam follower means connected to a member which is connected to the ladle at a point, said second cam being operative to overturn said ladle during its return from its pouring position to its filling position.

5. Apparatus as claimed in claim 4 wherein said second cam means has a gradually increasing radius followed by a sharp decrease in radius, and is driven for two turns during said overturning operation at such speed that, as the cam follower moves for the first time over the part of gradually increasing radius, the ladle is pivoted about said axis until the end remote from the lip approaches or passes through a position vertically above said axis, the cam follower then moving over the part of sharply decreasing radius so that the ladle continues to an inverted position owing to its momentum, this movement being sharply checked by the arrival of the cam follower on the cam part of small radius, whereby any molten metal or oxide remaining in the ladle is knocked out, further rotation of the gam means causing the cam follower to move for the second time over the part of gradually increasing radius thus causing the ladle to pivot about its axis in the opposite sense of rotation until the end remote from the lip approaches or passes through a position vertically above said axis, the cam follower then moving for the second time over the part of sharply decreasing radius so that the ladle continues to its noninverted position.

6. Apparatus for the automatic transport of molten metal from a furnace to a casting die or mould, including a rotatable column arranged to rotate about a substantially vertical axis, a pair of arms jointed to the column, and arranged to rotate about a substantially horizontal axis, a first member parallel to the column and jointed to the outer ends of the arms so as to form a parallel motion linkage, a ladle joined to said first member at a first point on the ladle, a second member movable relative to the first member and joined to the ladle at a second point spaced from the first point, so that movement of said second member causes pivoting of the ladle around said first point, and motordriven cam means arranged to control movement of said second member, said members and said cam means being so arranged as to overturn the ladle after pouring, whereby to knock out any metal or oxide remaining therein.

7. Apparatus as claimed in claim 6 for the automatic transport of molten metal from a furnace to a casting die or mould, including two concentric rotatable columns arranged to rotate about a substantially vertical axis, a pair of arms jointed to each column, and each arranged to rotate about a substantially horizontal axis, a pair of first members parallel to the column and jointed to the outer ends

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. has two sets of arms, one set 18a, 18b, 19a, 19b supporting a ladle 11, and a second set 18a', 18b', 19a', 19b' supporting a ladle 11'. Two holding furnaces 12A, 12B, are shown, of which only one may be in use at any given time, while the other is being refilled. The holding furnaces may be on a turntable 72, so that in one position of the turntable one furnace, say 12A, may be in a position in which the ladles 11, 11' can be filled from it, while furnace 12B is filled, and vice versa. In Fig. 13, ladle 11, when filled as described above, transports metal to and pours it into the die cavities of die-casting machine 13A, and ladle 11' pours metal into machine 13B. The sequence of operations will be arranged so that, for example, ladle 11 is filling in the furnace while ladle 11' is pouring, and vice versa. WHAT WE CLAIM IS:-

1. Apparatus for the automatic transport of molten metal from a furnace to a casting die or mould, including cam means which automatically control the position of the ladle in the vertical plane throughout the cycle of operation, wherein the cam means includes means automatically to overturn the ladle after pouring, whereby to knock out any metal or oxide remaining therein.

of the respective pair of arms so as to form parallel motion linkages, a pair of ladles, each joined to one of said first members at a first point on the ladle, a pair of second members movable relative to the respective first members and joined to the respective ladles at a second point spaced from the first point, so that movement of each said second member relative to the respective first member causes pivoting of the respective ladle around its first point, and a pair of motordriven cam means arranged to control movement of the respective second member, whereby two ladles may be in operation at the same time to pour metal into two spacedapart dies or moulds.

8. Apparatus as claimed in claim 7 wherein the spacing of said two dies or moulds is substantially equal to the sum of the radii of the first points of the respective ladles about said substantially vertical axis.

9. Apparatus as claimed in either of claims 7 or 8 in which the two ladles transport metal from the same furnace to the two dies or moulds, the ladles being filled one after the other.

10. Apparatus for the automatic transport of molten metal from a furnace to a casting die or mould, substantially as hereinbefore described with reference to and as illustrated in Figures 1-3 of the accompanying drawings.

11. Apparatus for the automatic transport of molten metal from a furnace to a casting die or mould, substantially as hereinbefore described with reference to and as illustrated in Figure 13 of the accompanying drawings.