US1950864A - Die-casting machine - Google Patents

Description

March 13, 1934. R. J. SCHULTZ DIE CASTING MACHINE 3 Sheets- Sheet 1 Filed Dec.

March 13, 1934. R. J. SCHULTZ 1,950,864

DIE CASTING MACHINE Filed Dec. 27, 1930 3 Sheets Sheet 2 March'lB, 1934 R. J. SCHULTZ 1,950,854

DIE CASTING MACHINE Filed D60. 27, 1930 3 ShGQtS- Sheet 3 4: ww 4 I 1 6 +r w vm .m 5/ 1 W 5. MW 6 5 n V f M0, :5! ,5 w mm A mm O G v p m a w w 5; & -L

Patented Mar. 13, 1934 1,950,864 DIE-CASTING MACHINE 7 Raymond J. Schultz, Madison, Wis., assignor to Madison-Kipp Corporation,

Madison, Wis a corporation of Wisconsin Application December 27,1930, Serial No. 505,159

' 2 Claims.

into the die by fluid under pressure.

In such machines, there is provide d usually a fixed or movable pressure chamber or goose neck which receives the molten metal from the melting pot. Pressure fluid, such as compressed air, isadmitted then to the goose neck through a valved-connection in a pressure I suitable pressure the discharge nozzle of the goose any other means,

line or from fluid supply neck being in communication with the closed This fluid, entering behind the molten metal in the goose neck, forces the metal therefrom and into the closed die. Automatic means are provided for operating the air inlet for the purpose mentioned after the die has closed. Before the die opens, the inlet valve closes and an exhaust valve opens to vent the parts and relieve the fluid pressure on any metal remaining in the pressure chamher. If this were not done, when the die opened the molten metal in the pressure chamber would be ejectcd therefrom, probably resulting in in: jury to the operator and damage to the machine.

It is the primary purpose of the present in- I vention to eliminate entirely the hazard of shooting metal when the die is open. In fact, in order to increase the safety factor further, it is contemplated that ejection of the metal shall be impossible except when the pressure chamdie at this time.

her and the die are in die charging relation, at which time, of course, the die is closed. Experi ence has shown that, even though the vent for the compressed air and the gases is open and this condition exists as long as the die is open or the goose neck is not in charging position, if for any reason the air inlet valve is operated or has not completely closed following a previous operation, the-compressed air released thereby will still act with sufficient force on any metal in the goose neck to eject it from the discharge nozzle thereof with-the possibility of serious injury to the operator.

This objectionable condition has been overcome completely in the present apparatus by interconnecting the exhaust or vent valve and an auxiliary or safety valve located between the I air inlet valve and the source of 'compressed'air supply. These valves operate so that the auxiliary or air supply control valve always is closed when theexhaust valve is open, and open when the exhaust valve is closed. Since the exhaust valve is adapted a .ways to be open when the die halves are separated and the air supply valve is closed at this time, neither incomplete closing nor operation of the inlet valve will cause compressed air to be furnished to the goose neck and eject metal while the die is open.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which:-

Fig. 1 is a side elevation of the machine with the die in its open position, at which time the 5 air inlet valve is closed and the exhaust valve is open to permit the venting of gases and compressed air from the pressure chamber and the connections leading thereto;

Fig. 2, a plan view of the same, with shown in the same relative positions;

Fig. 3, an end elevation of the pressure fluid system as it appears when viewed from the right hand end of the machine as shown in Fig. 1;

Fig. 4, a front elevation of the combined exhaust and cut-off valve, the parts being broken away somewhat to show the interior construction;

Fig. 5, a section taken on line 5-5 of Fig. 4, showing the cut-oil valve and the entry for the g0 pressure fluid from the source of supply;

'Fig, 6,'a vertical, longitudinal section of the inlet valve as it appears at the rear of the machine in Fig. 2; and.

Fig. 7, a section taken on line 7-7 of Fig. 6, showing the inlet valve in partand the port leading to the exhaust.

Since the features of the invention herein set forth .are particularly applicable to die-casting machines of the type disclosed by.certain earlier patents granted to Torbjorn C.Korsmo, although limited thereto, special reference is the parts 70 in no way made to these patents herein.

Patent No. 1,607,677, granted to said Korsmo November 23, 1926, relates to the general construction and, operation of the machine. Pate ents No. 1,590,246, granted June 29, 1926, and No. 1,631,686, granted June 7, 1927, to Korsmo, disclose the means for openingand closing the die, while his Patent No. 1,627,784, granted May 10, 1927, sets forth the operation of the inlet and exhaust valves for the pressure fluid which forces the molten metal into the die. Although suchreference to related features of the machine will be made herein as is essential to a complete understanding of the invention, the details of these features are to be found in the patents just mentioned.

Referring to the accompanying drawings, the machine comprises a bed 1 which supports a gear housing 2 provided with a cover 2'. The right-hand wall 3 of housing 2 supports'the ends of a series of four. horizontal guide rods 4, 4, 4', 4, only the front pair 4, 4 of which are shown in the drawings.

Since a large number of the parts of the machine, including the guide rods just referred to, are duplicated at the front and the rear of the structure, only the front set will be described, corresponding, primed reference characters being used to indicate the parts at the rear, which latter in some instances it has not been deemed necessary to illustrate.

The opposite ends of guide rods 4, 4, 4', 4' are supported by hot plate 5. This hot plate carries the stationary part 6 of the separable die, while the hot plate itself surmounts a frame member 7. Member 7, which is bifurcated at its lower end to straddle the combined furnace and melting pot 8, is supported on bed 1 by guide rods '-10, 10' and brackets 9, 9' (only the front set of which is shown).

The usual goose neck or pressure chamber 11, having an outlet nozzle 12, is shown pivotally mounted by means of a pin 13 on a second frame member 14 also carried by guide rods 10, 10'. The discharge end of the goose neck is pivotally supported at 15 in a vertically movable yoke 16, whereby the goose neck through movement of the yoke may be swung up and down about its pivot pin 13. As it appears in Figs. 1 and 2, nozzle 12 of the goose neck is submerged in the molten metal in melting pot 8, whereby the goose neck receives a quantity of metal preparatory to charging the die.

.A nozzle 17 on the opposite end of goose neck 11 serves, as indicated in dotted lines in Fig. 1,

a to connect goose neck 11 to a pressure-fluid conall times with the periphery nection 18, when the goose neck is in its elevated or die-charging position. Connection 18 is mounted on frame member 14 and has a passage 19 therethrough. Passage 19 is adapted to be connected periodically through pipe 20 with 'a source of pressure-fluid supply to eject the metal from goose neck 11 into the die, as will be explained in detail later.

Attached to a die carriage 21, which is mounted for reciprocation on guide rods 4, 4, 4', 4', is the movable die part 22. Power for reciprocating the die carriage 21 is derived from a drive shaft 23 the ends of which are journaled in the sides of housing 2. Housing cover 2 conceals the gearing which drives shaft 23 from a suitable source of power, such as an electric motor.

The ends of shaft 23 carry cranks 24, 24 having cams 25, 25' secured thereto. Each of earns 25, 25 carries a roller 26 engaging a slot 27 in the end of a connecting rod 28. A roller 29 on the inner face of connecting rod 28 engages at of cam 25.

At their opposite ends the front and rear connecting rods 28, 28 are joined together by a cross member 30 (see Fig. 1). Cross member 30 is fixedly secured on a pair of die carriage pusher rods 31, 31' (only the forward one of which is shown), the pusher rods being extended on either ,side of cross member 30 so as to project through suitable guideways 32, 32', 33, 33' provided for this purpose on hot plate 5 and the right-hand end of housing 2.

Each of pusher rods 31, 31' extends through a split bearing 34 on the edge of die carriage 21. Pusher rod 31 is threaded to receive a pair of nuts 35 to the right and a pair of nuts 36 to the left of the die carriage. A coil spring 37 located between nuts 36 and die carriage 21 serves to urge the carriage towards the right and against nuts 35'. The purpose of this will appear shortly.

Pivotally connected at one end to cross member 30 is an elevator pusher rod 38, which together with a corresponding rear pusher rod 38, serves to operate the goose neck 11. The opposite end of rod 38 has a. pin-and-slot connection at 39 with the upper arm of a bell crank 40. The other arm of the bell crank and the corresponding arm of the rear bell crank 40' serve, when the machine is operating, to effect the necessary raising and lowering of yoke 16 to move goose neck 11 between its charge-receiving and die-charging positions, as will be readily understood.

No claim is made herein to the mechanisms so far described, since these are fully covered by the prior patents to Korsmo, Nos. 1,590,246; 1,607,677; 1,627,784; and 1,631,686, supra. Reference may be had to these for further details.

The general operation of the parts so far described is as follows. Assuming the parts are in the position of Figs. 1 and 2, with the die open and a quantity of metal in the goose neck, when power is applied to shaft 23, connecting rods 28, 28' will move to the right and impart a corresponding movement to cross member 30, die carriage pusher rods 31, 31' and elevator pusher rods 38, 38'. As a result, die carriage 21 will be moved to the right on guide rods 4, 4, 4', 4 until movable die part 22 engages fixed die part 6. Simultaneously, discharge nozzle 12 of the goose neck is raised by the connections described into contact with a perforated nipple plate 41 pivoted on the under side of the fixed die part 6 (see Fig. 1). Following this, the goose neck 11, as explained below, has a final upward movement which carries the nipple plate 41 into contact with the closed die, and thus, connects the interior of the goose neck with the die through the opening in the nipple plate 41. L

Die carriage 21 is primarily adjusted on the pusher rods 31, 31' and secured by nuts 35,36, so that the die parts 6 and 22 are brought into contact shortly before cross member 30 completes its movement to the right. Hence, when the die parts are brought together, cross member 30, continuing its movement to the right, causes coil springs 37, 37 to be compressed against die carriage 21, pusher rods 31, 31 sliding freely through their bearings on the die carriage to permit this action. During this short relative movement between cross member 30 and die carriage 21, goose neck nozzle 12 is moved, together with nipple plate 41, into the die-charging position indicated in dotted lines in Fig. 1.

Thus, it will be seen that the die is closed simultaneously with the raising of goose neck nozzle 12 into contact with nipple plate 41, following which nozzle 12 forces the nipple plate against the bottom of the closed die. During this movement of the parts into die-charging position, rear nozzle 17 of the goose neck seals against pressure fiuid connection 18. Certain valve mechanism, to be described shortly, is then automatically actuated to supply pressure fluid to the goose neck through connection 18 and thereby force the molten metal from the goose neck into the die. The supply of pressure fluid is then automatically cut off and the pressure fluid vented from the goose neck and connected parts before the die opens.

The die operating mechanism is designed to casting. The die actuating mechanism then operates in the opposite direction, carrying connecting rods 28, 28 to the left, together with cross member 30. As a result, goose neck nozzle 12 starts to descend, together with nipple plate 41. As cross member 30 and die carriage pusher rods 31, 31' continue their movement to the left, nuts 35, 35 engage the die carriage and move it to the left, so as to separate the die parts 6 and 22. As goose neck 11 descends, the seal at nozzle 17 is broken and the parts vented at this point.

The parts continue their movement to the left, the casting is removed, and finally the full opened position of Fig. l is reached. The parts described are now ready for the next c'asting operation.

.The means forsupplying pressure fluid to dis-. place the molten metal in the goose neck and for venting the goose neck and the connected parts will now be described. Pipe 20 leading from pressure fluid connection 18 connects at its opposite end to inlet valve casing 42 suitably mountedon hot plate 5 (see Fig. 2). The interior of valve casing 42 is divided into two chambers 43, 44, the latter of which is connected by a pipe 45 to a second valve casing 46 at 47.

The chamber 43 of inlet valve casing 42 is also connected by means of a pipe 48 to valve casing 46 at 49. Communication between the two chambers 43, 44 in valve casing 42 is controlled by an inlet poppet valve 50, having a stem 50 projecting outside the valve casing. A coil spring 51 serves to maintain valve 50 in its normal closed position, as shown in Fig. 6.

Valve casing 46 serves to house both the exhaust valve for venting the parts and anauxiliary or safety cut-off valve for preventing passage of pressure fluid to the goose neck 11 when the die is open, or the goose neck disconnected from the die. Casing 46 has an intermediate cylindrical portion 52 in which a piston type, cut-off valve 53 is located for, reciprocatory movement. Cut-off valve member 53 serves to divide the interior of valve casing 46 into two chambers 54 and 55. Chamber 54 connects by' means of pipe 48 with the upper part of chamber 43 of the inlet valve casing 42. This chamintegrally with cut-off valve 53 and having a stem 57 projecting outside the valve casing. Opening 58 in the end of valve casing 46 is closed by a screw plug 59 against which bears a coil spring 60 which serve to urge exhaust valve 57 towards closed position.

When exhaust valve 5'7 is closed, as shown in Fig. 4, it will be noted that cut-off valve 53 is sufficiently farto the left to uncover a port 61 leading from chamber 55 into pipe 45, which latter connects with chamber 44 of inlet valve casing 42. A similar, alined inlet port 62' on the opposite side of chamber 55 also is uncovered by cut-off valve 53 at this time. A pipe 62 connects inlet port 62 with a suitable source of pressure fluid supply. Preferably, supply pipe 62' passesthrough furnace 8, as shown in Fig. l, in order to preliminarily heat the pressure fluid. With the described arrangement of the parts,

'69 to the left.

surface '73.

it is clear that, when cut-oil? valve 53 is in the open position of Fig. 4, compressed air entering chamber 55 of valve casing 46 through inlet port 62 will pass out through port 61 and be carried by pipe 45 to the inlet side of valve 50, i. e., into chamber 44 (Fig. is). When inlet valve 50 is opened against the resistance of this flu'id .pressure and that of spring 51, compressed air will flow through valve casing 42 and to goose neck 11 by way of pipe 20. At the same time, com-- pressed air will flow from chamber 43 by way of pipe 48 into chamber 54 of exhaust valve casing 46. However, since exhaust valve 57 is closed, the compressed air is retained in chamber 54 and cannot escape to the atmosphere.

When exhaust valve 5'7 is opened, chamber 54 of valve casing 46, pipe 48, chamber 43 of valve casing 42, pipe 20 and goose neck 11 are allimmediately vented to atmosphere by means of exhaust port 56. At the same time the resulting movement of safety valve 53 to the right closes ports 61, 62, and cuts-off the fluid supply from the system. Therefore, at this time, i. e.,

i when the exhaust valve 57 is open, should inlet valve 50 be operated or, following a previous operation, be not completely closed because, for instance, of dirt on the valve seat, it would be impossible for the system to supply compressed air to the goose neck 11. However, if the inlet valve 50 is operated at any time when the exhaust valve 5'7 is closed, the position of cutoff valve 53, as appears from Fig. 4, is such as to permit the ready passage of compressed air to the system, past inlet valve 50, and through the described connections, to goose neck 11.

The inlet and exhaust valves of the pressure fluid system are adapted to be actuated at the proper times through certain mechanism controlled by the main drive shaft 23. This shaft rotates in a counter clockwise direction, as indicated in Fig. 1. On the front end of shaft 23 is a cam 63, the periphery of which is providcd with a main camming surface 64 and a depressed camming surface 65. This cam is adapted to operate the exhaust valve 5'7 and with it the cut-off valve 53.

Pivotally mounted at 66 on the side of gear housing 2 is a bell crank 67 having a roller 68 at the end of one arm thereof engaging the periphery of cam 63. The other arm of bell crank 67 is engaged by an. adjustable head 69 on one end of a thrust rod 69 which extends through the hollow guide rod 4. The opposite end of thrust rod 69 projects beyond hot plate 5 for engagement with stem 5'7 of exhaust valve 57 to open the valve at the proper time. Coil spring '70 serves to urge thrust rod 69 to the left, and consequently, force roller 68 against cam 63.

When roller 68 is in engagement with cam surface 64, which comprises the greater part of the periphery of the cam, thrust rod 69 operates to open exhaust valve 57 and vent the. parts. As shaft 23 revolves, roller 68 comes into contact with the depressed cam surface 65, thereby permitting coil spring '70 to force thrust rod This permits coil spring 60 to close the exhaust valve 5'7.

The mechanism for operating inlet valve 50 is identical with that for operating the exhaust valve, except for the operating surface of the cam member. This cam '71 is secured on the rear end of drive shaft 23. Cam 71 has a main peripheral surface '72 and a raised operating As long as roller 68' of the inlet valve operating mechanism is in contact with the main surface 72 of cam 71, the inlet valve 50 is retained in its closed position by coil spring 51, as shown in Fig. 6. However, when raised portion 73 of cam 71 engages roller 68, bell crank '67 and thrust rod 69 are operated to the right to open inlet valve 50.

It is necessary, of course, that the mechanism described for controlling the pressure fluid system be arranged to operate the valves in properly timed relation to the operation of the goose neck and the opening and closing of the die. With the arrangement of parts and the forms of the cams 63, 71 as they appear in Figs. 1 and 2, thesequence of operations is as follows.

Starting with the charge-receiving position of goose neck 11, as shown in Fig. 1, it will be seen that at this time the die is open; also, that the seal between air nozzle 1'7 of the goose neck and fluid pressure connection 18 is broken to permit venting of the rear end of goose neck 11. At the same time, pipe 20 is vented to the atmosphere through connection 18. The position of valve operating cam 63 is such that exhaust valve 57 is held open so the remaining parts of the pressure fluid system can vent to the atmosphere. Cut-off valve 53, therefore, is closed and the position of valve actuating cam 71 permits spring 51 to hold inlet valve 50 closed also. Even though inlet valve 50 were opened at this time, it is obvious that no pressure fluid would be delivered to the system.

As drive shaft 23 continues to revolve, nozzle 17 seats against pressure fluid connection 18, the die is closed, and discharge nozzle 12 of the goose neck engages nipple plate 41. Pusher rods 31, 31 then move relatively to die carriage 21, effecting the final upward movement of goose neck 11, whereby nipple plate 41 is forced into engagement with the die and the interior of the goose neck connected with the die cavity. By this time, cam 63 has revolved so as to permit coil spring 60 to close exhaust valve 57. Shortly after this, raised portion 73 of cam 71 acts through the connections described to open inlet valve 50. The shape of cam portion 73 is such that the inletvalve is held open for but a brief period, being quickly closed by its sprin 51 as roller 68' again comes into contact With the main portion 72 of cam 71.

During this operation, exhaust valve 57 has remained in closed position to permit compressed air to pass through the fluid pressure system and act on the metal in the goose neck to discharge it into the die. Shortly after the closing of the inlet valve 50 and after sufficient time has elapsed for the charge in the die cavity, to

' freeze, but before the die starts to open, or

the goose neck starts to descend, cam 63 operates to open the exhaust valve 57 and vent the parts. This occurs as soon as roller 68 engages the main camming surface 64 of cam 63, the exhaust valve remaining open until the die closes the next time.

Shortly after the opening of the exhaust valve, pusher rods 38, 38' operate to lower goose neck nozzle 12 and permit nipple plate 41 to resume its original position. 'The die then opens and the connection at the rear of the goose neck with the pressure fluid system is broken. Continued movement of the parts brings them back parts are not in proper, position to shoot a casting, exhaust valve 57 is held open, while supply control valve 53 and inlet valve 50 are closed. Hence, should the operator unintentionally open inlet valve 50 or the valve be not completely closed at this time, no compressed air would be supplied to eject molten metal from the goose neck; nor, would reverse operation of the machine cause compressed air to be released as long as exhaust valve 57 is open, and cut-off valve 53 closed.

It has been found that in machines of the character herein described, in which a safety cut-off, such as valve 53 or its equivalent, is not present, even though the exhaust valve, or other venting means, is open, operation of the inlet valve will result in the compressed air acting through the system with sufficient force to eject molten metal on or into thedie. Thus, it is highly desirable to shut off the compressed air supply ahead of the inlet valve in the manner provided in the present machine;

What is claimed is:

1. A pressure fluid system for die casting machines of the type in which molten metal is displaced from a pressure chamber into a die by fluid pressure, comprising pressure fluid conducting means adapted to connect said pressure chamber with a source of supply; an inlet valve located in said conductor for controlling flow of pressure fluid to the pressure chamber; an exhaust valve for venting the system between the inlet valve and the pressure chamber; and an auxiliary valve located in the fluid conductor between the inlet valve and the source of supply and connected to the exhaust valve so as to prevent flow of pressure fluid to the inlet valve while the exhaust valve is open.

2. A pressure fluid system for die casting machines of the type wherein molten metal is forced from a pressure chamber into a die by fluid pressure comprising pressure fluid conducting means for connecting the pressure chamber with a source of pressure fluid supply, said conducting means including an inlet valve casing having an inlet port, an outlet port leading to the pressure chamber and a vent port; a normally closed valve for said inlet port; an exhaust valve casing; a normally closed cut-off valve dividing said exhaust valve easing into separate chambers, one of which has an inlet portand an outlet port controlled by the cut-off valve and forms part of the pressure fluid conducting means between the inlet valve and the source of supply, the other chamber having an exhaust port and a port connected to said vent port of the inlet valve casing; and a normally open valve for said exhaust port, the exhaust valve and the cut-off valve being connected together for simultaneous operation to close the cut-off valve when the-exhaust valve is opened and vice versa.

RAYMOND J. SCHULTZ.

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