US2535335A - Apparatus for chill casting - Google Patents

Description

Dec. 26, 1950 M. THEVENIN 2,535,335

APPARATUS FOR CHILL-CASTING Filed March 19, 1948 s Sheets-Sheet i FIG. 1

Dec. 26, 1950 M. THEVENIN APPARATUS FOR CHILL-CASTING 5 Sheets-Sheet 2 Filed March 19, 1948 l'nvenfbr' KB nave/1:17

fiffomgy Dec. 26, 1950 M. THEVENIN APPARATUS FOR CHILL-CASTING 5 Sheets-Sheet 3 Filed March 19, 1948 777 vemwy Dec. 26, 1950 M. THEVENIN 2,535,335

APPARATUS FOR CHILL-CASTING Filed March 19, 1948 5 Sheets-Sheet 4 Dec. 26, 1950 I M. THEVENIN APPARATUS FOR CHILL-CASTING Filed March 19, 1948 5 Sheets-Sheet 5 In van for M! 775a yen/r Patented Dec. 26, 1950 UNITED STATES PATENT OFFICE Application March 19, 1948, Serial No. 15,902 In France March 21, 1947 6 Claims.

The present invention relates to an improved apparatus for casting wherein the molten metal is cast in a series of molds intermittently moved so as to position each mold successively below a tap-hole which is opened and closed for the time necessary for a casting operation. The opening of the mold for discharge of the finished casting is determined in synchronous timed relationship to the intermittent movements of the molds and the closure of a mold prior to casting is similarly determined.

An object of the invention is to provide an apparatus so that a continuous operation of the furnace may be secured so that losses in heat are reduced to a minimum thereby economizing on fuel or electricity.

A further object of the-invention is to make the operations entirely automatically thereby securing a substantial saving in labor.

A further object of the invention is to provide a casting apparatus which is highly advantageous for the lighter alloys but is also advantageous in connection with other metals and other alloys.

With the above and other object in view which will appear from the following detailed description a preferred embodiment of the invention is shown in the drawings in which:

Fig. 1 is a front view with parts in cross-section of an apparatus according to the invention comprising two molds;

Fig. 2 is a front View of the apparatus according to Fig. 1 with one of the molds located in casting position under the tap-hole of the furnace;

Fig. 3 is a cross-sectional view taken on section line III-III of Fig. 2;

Fig. 4 is a partial diagrammatic view with certain elements in cross-section showing the electromagnetic means for opening and closing the tap-hole; and

Fig. 5 is a detailed view illustrating a modified construction for opening and closing a separable mold.

In the various figures similar reference characters indicate like parts.

A melting furnace is shown at ID for the alloy or metal to be cast which is provided with a casting jet or nozzle Under the furnace l there is located a circular plate 2| rotatable about a vertical tubular shaft 23 secured to the frame 8.

On the plate 2| are secured projecting arms 2| which support separable molds formed of two sections 44 and 45. position on the arm 2! while the cooperating section 45 is movable. In the construction shown there are only two molds shown as supported by The section 44 is fixed in on a shaft 49'.

the plate 2| but it is obvious that any number of molds may be provided as desired.

The plate 2| is supported on a ball bearing thrust bearing l which is in turn supported on a plate 22 having a laterally extending projecttion 22.

The plate 22 has fixed thereto a helical gear 24 which is concentric with the tube 23 and meshes with a worm gear 25. The worm gear 25 is fixed to a pulley P which is driven by a motor M through the transmission belt 21.

The plate 2| is intermittently driven by means of the lugs 25 which are slidable within a slot formed in the plate 2| and in which such lugs are supported. The lugs 25 cooperate with the projection 22 upon the plate 22 in order to drive the plate 2| with the plate 22 until the driving lug is removed from contact with the nose 22' by a cam 28 supported on arms fixed to the frame 8. When a driving lug 26 is removed from contact with the plate 22 then the drive of the plate 2| is only resumed after the plate 22 has made a half revolution when the projection 22' contacts the other lug 26.

The means for opening and closing the separable molds will now be described. This comprises a lever 33 freely rotatable upon the plate 22. The lever 33' i also adapted to be driven by the projection 22' through a drive lug 25 which is mounted vertically slidable in the lever 33. The lug 26' is urged upwardly by a spring 34 and is moved away from the path of the projection 22 when acted upon by a cam 28' mounted upon a slideway 38 having two arms between which the lever 33 may freely move.

The lever 33 is retained in or restored to its initial position when not driven by means of a cable 35 having one end attached thereto. The cable 35 passes over rollers 42 and 43 which are rotatably mounted on the frame 8. The other end of the cable 35 is attached to a member 86 supported on a carriage 65 which is horizontally slidable in a slideway formed in the frame 8. The carriage 65 is returned to initial position by a return spring 61 having one end secured to the frame 8 and the other end to the carriage 65.

The closing of a mold is effected by a mechanism including a cam of spiral form, see Fig. 3, which is supported by brackets 1i] secured to the frame 8.

The movable section 45 of the mold is slidable upon horizontally extending rods 43 and is supported on a fork 64 slidable in a support 41 pro vided at the free end of the arm 2|. A rod 53 is in turn slidable axially of the fork 64. The rod 53 has mounted thereon a stub shaft or pin 55 cooperating with the fork of a lever 48 pivoted The opposite end of the lever 48 has mounted thereon a freely rotatable roller 3|. There is also mounted on the lever 48' a leaf spring 3! which can be adjusted by means of a set screw 31.

The means for opening and closing the tap.- hole H is preferably accomplished by electromagnetic means will now be described.

Above the furnace l5, see Fig. 4, there is arranged a substantially horizontal balance lever l4 pivoted on a shaft 2 mounted upon a, fixed support 2. At one end the lever I4 is provided. with a helical groove it into which a pin t2 upon the rod 12 projects. At its. opposite. end the lever M- coacts with a pin I mounted on a part: ii which forms the end of a vertical arm l5. comprising a pair of threaded rods I5 which are interconnected by means of a turn buckle 8. The arm [-5 at its lower end carries a member 3 pivoted upon a pivot pin 5 mounted upon the armature ll of an electromagnet A. The armature I is pivoted at one end at 4.

Normally when the tap-hole H is closed by the rod !2 when no current flows through the winding of the electromagnet A a spring 20 secured at one end to the part 6 and at the other end to a bracket 5 secured to the furnace maintains the armature H away from the electro-- magnet A by pivoting the armature ['1' about pivot 4. Fig. 4 shows the position of the parts when casting is taking place and the spring 20 is: in extended condition.

In order to close the tap-hole H a second electromagnet B having a movable armature 4i]. pivoted at one end on a pivot 4| is used. The current for both electromagnets A and B is sup-- plied through the lines C and C.

During rotation of the plate 21 carrying the molds the current is normally broken.

Mounted upon the furnace H] as shown particularly in Fig. 4 is a casing H constructed of insulating material having therein fixed contacts D and E. Cooperating therewith are the movable contacts 13 and E mounted on the rods T slidably mounted in the casing H. The opposite ends of the rods T are provided withthe contacts F and G. The springs S'normally maintain the contacts D, D and E, E disengaged as long as the conductive plates F and G upon the arm 21' are not in contact with the contacts F and G. Such contact however is made as soon as the plate 2i is stopped with a mold located under tap-hole I l.

The contact plates F and G are connected to a suitably insulated circuit shown in dotted lines to the terminals J and J located at a predetermined level upon each mold so that when the molten metal reaches such level a circuit is established between J and J.

The terminals J and J are furthermore; electrically connected to a pair of contacts K and. K, which are located rearwardly of the plane shown in Fig. 4. The contacts K and K will engage one another in case the mold for any reason is imperfectly closed.

The line C is provided with a pair of contacts L and L which are in contact with one. another only when, the armature as having an extension 45 exerts pressure upon contact" L in order to maintain it in contact with the conmold accurately positioned under the tap-hole H the contact plates F and G will move the contacts F and G upwardly and close contacts D, D and E, E.

The. winding of the electromagnet A will then be energized and the armature I l" attracted which will pivot the balance lever l4 thereby raising the rod I2 which is also subjected to a slight rocking movement because of the helical form of the groove l'3. When the mold is filled and the molten metal has reached the level of the terminals J, J then the current is established through the terminals J, J and the contacts 11E energizing the winding of the electromagnet B which attracts its armature 40 thereby breaking the current through the line C which deenergizes the winding of electromagnet A and allows the spring 20 to come into action to rock the lever l4 counterclockwise as shown in Fig. 4 thereby closing the tap-hole ll upon downward movement of the rod 121 In such downward movement the rod 12 is also subjected to' a slight angular rotation which facilitates atight sealing engagement with the tap-hole.

If the mold should be imperfectly brought together i-n casting position then the contacts K and K would be brought into engagement and since these contacts are electrically connected with the terminals J and J theeffect is the same as set forth above. The electromagnet B will be energized and the current broken at L, L" to deenergize the electromagnet A.

Relative movement between the sections 44 and 45 of each mold may be made in various ways. Fig. 4 shows a preferable embodiment applicable for instance in casting a wheel W. The pin 53 on the rod 53 slides withina slot 50 provided in the fork 64. The end 53 of the pin 53 serves as a core for the hub of the wheel when the mold isclosedfor a casting operation. When the lever 48 is rotated clockwise about its pivot 4'9 the extension 53 is moved before the fork 6' 3 and the movable section 45 is withdrawn.

In Fig; 5 a modified construction for opening a mold is shown. The shaft or pin 55" is fixed to the fork- 64 androtation of the-lever d8 about the fixed pivot as" directly moves the section 45 along the rods 46. The lever 48" is arranged horizontally and the mold shown in Fig. 5, is a plan view thereof. A second lever 52 is coupledthrough a pivoted link 5| to the lever 48. The lever 52 is pivoted on a pin H mounted upon the fork 64 and cooperates with a pin l2 provided on the rod 53.

A clockwise movement-of the lever #8 directly moves the fork 64 with the mold section 45. The ensuing pivoted movement of the lever 52* moves the pin 72 towards the right and thereby disengages the central extension 53 Upon continuation of the movement of the lever 43"" the roller 51 mounted freely rotatable on the pivotal shaft 13 engages a lever 5 t pivoted at 5% and thelever 54 moves a pin 63 fixed to a bushing slida-bly mounted on the rod 53. The bushing has mounted thereon spaced pins 62 which are operative to positively eject the casting. A return spring 60 restores the lever 5'4 to its initial position upon closing of the mold and a set screw 6| permits adjustment of the position of the lever 54.

Also a stop 29, see Fig. 2,, may be provided upon the furnace H1 to cooperate with a counterstop 29" provided upon. each movable section of the mold. The counterstop 29 will engage thestop 2 9 when the mold is closed and when the molds are in open position the counterstop 29 will avoid the stop 29. Furthermore vertically extending spring plates 68 are positioned so as to pass between the sections M and at of an open mold to positively eject any casting which might have remained wedged across the mold into an aperture 69 located beneath the mold.

The above described apparatus generally operates as follows:

Assuming the apparatus to be in the position shown in Fig. 3 and the motor started the projection 22' will drive the lug 2% with which it is in engagement. Thereupon the plates 2| and 22 will move in unison in the direction indicated by the arrow. The rotation of the plate 2i is continued until the lug 26 has been raised by the cam 28 sufliciently to remove it from the projection 22.

During this movement the mold associated with the lug 23 in engagement with the projection 22 will have been moved from its open to its closed position. This takes place because the related spring as frictionally engages the cam 55. At the end of the movement the position of the parts are as shown in Fig. 2 at the right thereof.

When the mold therefore reaches a position opposite the tap-hole I! it is in closed position and also the oppositely located mold is closed so that the stop 29 engages the fixed stop 23 to accurately position the mold in casting position.

As soon as a mold is in casting position the rod I2 is raised by the electromagnet arrangement above described. When the molten metal reaches the level of the terminals J and J the rod [2 is moved to close the tap-hole ii. During this entire casting operation the plate 25 remains stationary since the projection 22' must travel a half revolution before it will encounter the other lug 26 and the return of rotation of the plate 22 has been predetermined to secure a sufficient dwell period for the mold carrying plate.

During the time the plate 2| is stationary the driving plate 22 continues rotating. The projection 22 engages the lug 26' upon the arm 33. The arm 33 is therefore driven and the cable 35 is pulled to move the carriage 65 with the member 66 in a direction against the spring 67. This movement continues until the lug 26 is removed by the cam 28' from contact with the projection 22'. The member 66 cooperates with the roller 3| and thereby rocks the lever 58 of the mold which is opposite the one being filled from the tap-hole. This position of the parts is shown for the mold at the left in Fig. 2.

As soon as the opposite mold from the one being filled has been opened the stops 28 and 29' are disengaged and therefore movement of the plate 2| may be resumed when the projection 22 meets the lug 26 diametrically opposite the one which it has just left. When the plate 2| resumes its rotation the mold which has just been filled with molten metal is positively maintained closed as long as the associated spring 30 remains in frictional contact with the cam 55.

As indicated above the mold carrying plate makes one half revolution for each revolution of the driving plate. Immediately after a mold has been opened and during the initial phase of its rotational movement such mold will encounter the spring blades 68 which will eject any casting wedged therein.

The apparatus described is entirely automatic in its operation and the carriage may be arranged in any suitable manner other than that shown and in particular may be arranged so as to be capable of operating the lever 48 when such lever is in horizontal position as shown in Fig. 5.

Where the apparatus of the invention is used for the casting of aluminum or aluminum alloys, the rod serving to close the tap-hole may be made of cast-iron protected with a special surfacecoating suitably comprising sodium silicate, whiting and graphite. Care should be taken not to put it to use until the coating is perfectly dry. The rod rests on agraphite seating surface.

The open period of a mold may be put to use for cleaning and cooling it with a jet of compressed air or a liquid spray, depending on the size of the casting.

It will, of course, be understood that modifica= tions may be made in the above-described apparatus and means therein may be replaced by equivalent means without exceeding the scope of the invention as defined in the ensuing claims. Thus for instance in order to obtain a smoother drive for the mold carrier plate 2i means may be used for exerting a slight braking action on said plate. Moreover it will be understood that depending on the size of the foundry plant, all of the individual operations or any number of them may be effected automatically.

The essential feature of the invention primarily resides in the general organization of the casting operation as described above. It will be understood, for example, that this feature will be preserved if in the case of an assembly including two molds rectilineal reciprocation rather than a circular movement is imparted to said assembly so as successively to bring them beneath the tap-hole of the furnace.

What I claim is:

1. In a casting apparatus comprising a rotating support carrying a plurality of separable molds and adapted to successively position each of said molds under a tap-hole, the combination with said support of means for moving said support intermittently comprising a continuously rotating member coaxial with said rotating support and having a radial projection, lugs slidably mounted in said support and normally projecting into the path of said radial projection, there being a lug for each mold on the support and a fixed cam in the path of travel of said lugs to force said lugs out of engagement with said radial projection, said tap-hole and said cam bein so positioned with respect to each other that said cam is operative to disconnect a lug from driven engagement with the said projection when its related mold reaches a position under said tap-hole.

2. In a casting apparatus comprising a moving support carrying a plurality of separable molds and adapted to successively position each of said molds under a tap-hole, the combination with said support of means for moving said support intermittently comprising a continually moving member associated with said moving support and having a projection, lugs slidably mounted in said support and normally projecting into the path of said projection, there being a lug for each mold on the support and a fixed cam in the path of travel of said lugs out of engagement with said projection, said tap-hole and said cam being so positioned with respect to each other that said cam is operative to disconnect a lug from driven engagement with the said projection when its related mold reaches a position under said taphole.

3. In a castirg apparatus comprising a rotating support carrying a plurality of separable molds and adapted to successively position each of said molds under a tap-hole, the combination with said support of means for moving said support intermittently comprising a continuously rotating member coaxial with said rotatin support and having a radial projection, lugs slidably mounted in said support and normally projecting into the path of said radial projection, there being a lug for each mold on the support and a fixed cam in the path of travel of said lugs to force said lugs out of engagement with said radial projection, said tap-hole and said cam being so positioned with respect to each other that said cam is operative to disconnect a lug from driven engagement with the said projection when its related mold reaches a position under said taphcle, a lever pivoted on said rotating member, a flexible connection attached to the free end of said lever; a sliding block controlled by said flexible connection; return spring means associated with said block, a second lever for each mold pivotally attached to said rotating support, having one end pivoted to one portion of a separable mold and having its free end in engagement with said block when a mold is in mold opening position; a spiral cam extending in a plane substantially parallel to the plane of rotation of said rotating support, having its maximum radius extending in the general direction from said rotating support axis to said tap-hole; and a resilient member associated with each second lever engaging said spiral cam.

4. In a casting apparatus comprising a rotating support carrying a plurality of separable molds and adapted to successively position each of said molds under a tap-hole, the combination with said support of means for moving said support intermittently comprising a continuously rotating member coaxial with said rotating support and having a radial projection, lugs slidably mounted in said support and normally projecting into the path of said radial projection, there being a lug for each mold on the support and a fixed cam in the path of travel of said lugs to force said lugs out of engagement with said radial projection, said tap-hole and said cam being so positioned with respect to each other that said cam is operative to disconnect a lug from driven engagement with the said projection when its related mold reaches a position under said tap-hole, a first lever pivoted about the axis of said rotating member; a second slidable lug in said first lever also arranged in the path of said radial projection; a second fixed cam in the path of travel of said second lug to force said second lug out of engagement with said radial projection; a flexible connection attached to the free end of said first lever; a sliding stop block for each mold controlled by said flexible connection; return spring means associated with said stop block, a second lever for each mold pivotally attached to said rotating support, having one end pivoted to one portion of each separable mold and having its free end in engagement with said stop block when a mold is in mold opening position; a spiral cam extending in a plane substantially parallel to the plane of rotation of said rotating support, havin its maximum radius substantially parallel to the radius from said rotating support axis to said tap-hole; and a resilient member attached to each of saidsecond levers engaging said spiral cam.

5. In a casting apparatus comprising a rotating support carrying a plurality of separable molds and adapted to successively position each of said molds under a tap-hole, the combination with said support of means for moving said support intermittently comprising a continuously rotating member coaxial with said rotating support and having a radial projection, lugs slidably mounted in said support and normally projecting into the path of said radial projection, there being a lug for each mold on the support and a fixed cam in the path of travel of said lugs to force said lugs out of engagement with said radial projection, said tap-hole and said cam being so positioned with respect to each other that said cam is operative to disconnect a lug from driven engagement with the said projection when its related mold reaches a position under said tap-hole, electromechanical means for controlling said tap-hole comprising in combination; a plugging member for said tap-hole a first electromagnet having an armature; an energizing circuit for said electromagnet; a first pair of normally open contacts in said electrical circuit fixedly positioned with respect to said apparatus; contact plates on said rotating support, each associated with a related mold to close said first contacts upon the associated mold being positioned under said tap-hole; a second pair of normally open contacts in said energizing circuit; a second electromagnet having an armature; a mechanical connection connecting said second armature with said second contacts, and adapted to close said contacts when said second electromagnet is de-energized; a second energizing circuit for said second electromagnet connected to said first energizing circuit at one end; a third pair of normally open contacts in said second energizing circuit fixedly positioned with respect to said apparatus and adapted to be closed by said contact plates upon the associated mold being positioned under said taphole; and a fourth pair of fixed, spaced contacts in each mold near the upper end thereof and connected respectively to one of said first contacts and to one of said third contacts, adapted to be bridged by the metal in the mold When said metal reaches a predetermined level,- thus energizing said second electromagnet and opening said second contacts to break said first energizing circuit.

6. In a castin apparatus, as set forth in claim 5, wherein said electromechanical means further comprise a pair of conductive strips for each mold assembly, each strip being electrically connected with a related one of said fourth contacts and said strips being so shaped as to engage each other when said mold portions are not applied tightly against each other.

MARCEL THEVENIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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