US1631686A - Die-casting machine - Google Patents

Description

June 7 9 1927.

T. c. KORSMO DIE CASTING MACHINE Filed Feb. 5. 1926 2 Sheets-Sheet 1 r S ww/vt m 1 Tor'/br/z 612152157720,

June 7 192% T. c. KORSMO DIE CASTING MACHINE 2 Sheets-Sheet 2 Filed Feb. 5. 1926 Jig/WM el bho wm /l Patented June 7, 1927 Unitas stairs rarest" OFFICE.

TOJRIBJORN QONRAD KORSMO, 0F MADISQN, WISCONSIN, ASSIGNOR TO MADISON-RIP? CORPORATION, OF MADISON, WISCONSIN, A CORPORATION OF WISCONSIN.

DIE-CASTING MACHIN E.

original application filed March 6, 1925, Serial No. 13,543. Divided and this application filed February 5, 1926, Serial No. 86,285, and. in Great Britain October 28, 1925,

This invention relates to die casting machines and particularly to the mechanism in such machines for opening and closing the separable die parts incident to the charging of the die and the ejectionof the casting therefrom.

ln die casting machines employing separable dies, it is necessary to have certain mechanism for opening the die by separating the die parts to permit removal of the casting, and for then bringing the parts together again to receive another charge. After remaining closed for a period suflicient to permit the casting to freeze, the die is again opened by its operating mechanism and the ,casting removed. In cases where the operation of the machine is automatic, so that it carries out one or more casting cycles, without the assistance of an attendant, it is necessary that the die operating mechanism perform the above mentioned operations in timed relation with the operation of the other parts of the machine, such for instance, as the die charging and the casting ejecting mechanisms.

Heretofore, in die casting machine practice, the various die operating mechanisms used cause the separating movement of the movable die part (or parts} to begin at a very low' speed. During the interval the die is open the casting is ejected, after which, the operating mechanism causes the die to close, the ending cit the closing movement of the movable die part {or parts) also being effected with the movable part traveling at a 'very low speed.

in present practice, particularly where cores or the like are used in the die, or where portion of die cavity is formed in a die part which remains stationary when the die is opened, there is need of an eficient mechanism which will cause the movable die part (or parts) to begin the opening movement suddenly and at a comparatively high speed. When such a mechanism is used, the cores, in the one case, are pulled from the casting much more easily and cleanly, and in the other, the jerk of the opening movement serves very effectively to break the casting loose from the stationary part of the die.

It is a purpose of the present invention to provide a die operating mechanism of the character just described. It is further intended that the mechanism shall actuate the movable die part so as to slow up or decelerate the opening movement of the latter following the initial high-speed portion of this movement. After reaching its full-open position the movable die part is started on its closing movement by the operating mechanism. The closing movement begins comparatively slowly and is then accelerated. The comparatively slow movement of the die part at the ending of its opening and the beginning of its closing movements allows ample time for ejection of the casting, cleaning of the die cavity, lubrication of the die, placing inserts in the die, or any other operations which are necessary or, desirable be- 1 fore the next casting is made.

A further purpose is the provision of a die operating mechanism which, in closing the die, will operate to move and hold the die parts so that they fit accurately and tightly together. This is accomplished by designing the operating mechanism so that it will close the movable die part against the stationary die part at a time when the movable part is traveling at a comparatively high speed. Thus the movable part is suddenly arrested by collision with the other part.

The invention further contemplates that the die operating mechanism shall efiect a dwell oi the die parts in the closed position permit the casting to freeze; also, that the same mechanism shall serve, during the dwell, to lock the die in closed position against any pressure which might tend open it, such for instance, as pressure produced by gases within the die.

Further object is the provision a ma chine which permits ready change/oi dies and the use of dies of different sizes with a minimum of trouble,

This. application is a division. of a prior application for a die casting machine filed by me on March 6, 1925, Serial Number 13,543,

The accompanying drawings disclose a practical embodiment of the invention, wherein,

Fig. l is a front elevation of the invention showing the relative positions of the various parts when the die is in the full-open position and, in dotted lines, the position of the .die operating mechanism at a certain point Fig. 3, a planview with the parts in the full line position of Fig. 2; and

Fig. 4, a horizontal sectional view of a portion of the die operating mechanism.

The stationary part of a separable die is represented at 1 in the drawings and the movable part is shown at.2.- Die parts 1 and 2, when they assume the closed position of Fig. 2, form the die cavity 3, as a result of the co-operation of the usual depressions provided in the abutting faces of the die parts.

Stationary die 'part 1 is removably attached to the face of a hot plate 4, which latter forms a part of the main frame work of the machine. The movable die part 2 is removably mounted by any suit-able means on the opposing face of the carriage 5. This carriage is provided at its corners with a front pair of bearings, 6, 6 and arear pair of bearings 7, 7 through which extend a front pair of guide rods 8, 8 and a rear pair of rods 9, 9, respectively. Guide rods 8 and 9 at their left ends are fixedly mounted in hot plate 4 and similarly mounted in the left hand wall of a gear housing 10. The latter forms a part of the main framework of the machine. From the description just given, it will be seen that die part 2 is mounted so that it is adapted for reciprocation towards and from the stationary die part 1.

Located beneath stationary die part 1 is a melting pot 11 in which is mounted a" goose-neck or pressure-chamber 12 by means of which molten metal is transferred from the melting )ot into the cavity 3 ofthe die when it is c osed, as shown in Fig. 2. The mechanism for operating pressure-chamber 12 is not shown, since this formsno part of the present invention but is covered vby my previously filed application hereinbefore referred to.

Mounted for movement on the lower part of hot plate 4 is a perforated plate 13 with which the nozzle of pressure-chamber 12 co operates in charging the die. This also forms a part of-the subject matter of my other application just mentioned.

Provided on the front and rear edges of hot plate 4 are split bearings 14, 15, respectively. Similar bearings 16, 17 are provided on the front and rear edges, respectively,

of the left hand end wall of gear housing 10. Mounted for horizontal reciprocatory movement in bearings 14 and 16 is a rod 18.

at their opposite ends are.

A similar rod 19 is mounted in a like manner in bearings 15 and 17. .7 Die carriage 5 is provided on its front and rear edges with split bearings 20, 21, respectively, through which extend freely rods 18 and 19.

Inasmuch as the machine, as will appear from Fig. 3, is symmetrical, that is, the parts in the front of the longitudinal axis thereof are duplicated at the rear. of the axis, only the front part of the machine will be described in detail.

Rod 18 is threaded for a portion of its length on each side of bearing 20 on die -carriage 5. A pair of nuts 22 is mounted on rod 18 to the left of carriage 5 and a second pair of nuts 23 is mounted on the rod to the right of carriage 5. On rod 18 between the carriage and the pair of nuts 23 is a coil spring 24 mounted thereon so as to beunder compression at all times. Spring 24 and the correspondmg spring at the rear of the machine serve,'as will appear hereinafter, to hold die carriage 5 normally against the pair of nuts 22 and the corresponding pair of nuts at the rear of the machine.

To the right of the die is the front-connecting rod 25 of the mechanism for opening and closing the die by reciprocating movable die part 2 on its guide rods. Removably mounted on rod 18 towards its right hand end by means of suitable nuts is a block 25. Connecting rod 25 is pivotally connectedin any suitable manner to block 25. It will thus be seen that any horizontal reciprocating movement of the left hand end of connecting rod'25 will cause a corresponding parts. By adjusting the pairs of nuts 22,v

23 and the corresponding pairs of nuts at the rear of the machine, proper pressure between die parts of any size may be secured. Fig. 3 shows clearly the manner in which spring 24 and the corresponding rear spring are compressed when the die is closed. This results in a relative movement between die carriage 5 and rods 18, 19, so that in the closed position of the die, die carriage 5 is spaced from the pairs of nuts 22, 22. However, when rods 18, 19 are again moved to the right by connectingrods 25, 25 to open the die, the pairs of nuts 22, 22 again engage die carriage 5 and carry it to the right on its guide rods as 18, 19 continue their movement in this direction. During the entire time the die is open, springs 24, 24 serve to maintain die carriage 5 against the pairs of nuts 22, 22.

As hereinbefore stated, one of the objects of this invention is to provide a driving mechanism for the movable die part 2 which will cause the latter to dwell in closed position for a suitable period to permit the charge of molten metal to freeze therein, after which die part 2 is separated from the stationary part 1 with a jerk, that is, the movable die part begins its opening movement with the part moving at a relatively high speed. The opening movement of the die part should then be decelerated gradually in order to allow ample time for such operations, for instance, as removal of the casting and lubrication of the die parts. The beginning of the closing movement should also be comparatively slow, in order to lengthen the period in which the operations just mentioned may be performed. After this the closing movement of the die part 2 should be gradually accelerated so that the ending of its closing movement will be relatively fast. The mechanism in the present machine for imparting the movements just mentioned to connecting rods 25, 25 and thence to movable die part 2 will now be described, I

Mounted in suitable hearings in gear housing 10, Fig. 3, is a rotatable shaft 26. Mounted centrally on shaft 26 is a worm wheel 27 adapted to be driven by any suitable means (not shown) so as to cause shaft 26 to revolve. Preferably these parts are operated so that shaft 26 revolves in a clockwise direction, as indicated in Figs. 1 and 2, and the following description is given with this understanding.

The ends of shaft 26 project beyond their hearings in housing 10 and mounted rigidly thereon are parallel cranks 28, 28. The mechanism connecting the front crank 28 and front connecting rod 25 is the same as that connecting the corresponding parts at the rear of the machine. Therefore, only the front mechanism will be described.

On the outer end of crank 28 there is provided a cam disk 29. Cam 29 is so formed that the major portion 30 of its periphery constitutes an arc of a circle. In the center of this circle on cam 29 there is suitably mounted a stud 31 which projects rigidly from the outer face of the cam. A very satisfactory manner of mounting stud 31 on cam 29 is shown in Fig. 4. With this arrangement, stud 31 is provided with a reduced shank which extends through an opening provided for this purpose in cam 29. The end of the shank of stud 31 is threaded, whereby the stud may be secured in place by means of a nut 32. Mounted for rotation on stud 31 is a ring-shaped roller 33. As clearlyshown the drawings, stud 31 for movable die and its roller 33 are disposed for free movement in a slot 34 provided in the righthand end of connecting rod 25.

The outer end of stud 31 is threaded to receive a nut 35 having an enlarged base portion 36 to retain connecting rod 25 on the stud.

Cam 29 is symmertical with respect to the center line of crank 28 on which it is mounted. The peripheral portion 30 of the cam constitutes the active or camming surface, as will appear hereinafter, while the remainder of the periphery, i. e., the peripheral portion 37, forms the dwell surface of the cam.

Mounted in a suitable openin in connect ing rod 25 a. short distance inward of slot 34, as shown in Fig. 4, is a second stud 38. This stud is also provided with a reduced threaded shank whereby it is rigidly mounted on connecting rod 25 by means of nut 39. The outer end of stud 38 has an annular enlargement 40. formed thereon for the purpose of retaining a ring-shaped roller 41 on the stud.

Operation z-Tt will be assumed that the parts of the machine are in the positions which they occupy at the middle of the dwell or closed position of the die. This is shown in full lines in Fig. 2. It will be noted that the various parts of the driving mechanism for the movable die part are so arranged and proportioned that, at this time, the centers of shaft 26, stud 31, stud 38 and the pivotal connection between connecting rod 25 and block 25' are in horizontal alignment with each other. Stud roller 41 is also in contact with the middle of the dwell 37 of cam 29. The parts thus being on dead cen ter, the die parts are locked in closed position at this time against any pressure tending to force the die parts apart. As will appear hereinafter, the driving mechanism entire dwell period to lock the die parts together against any such pressure as that just mentioned.

The parts of the die separating mechanism are arranged and proportioned so that, so long as stud roller 41 and the are shaped portion 30 of cam 29 are in contact stud roller 33 is confined in the outer or rightduring the dwel period, stud roller 41 mere ly rides freely thereon so as to permit the right-hand end of connecting rod 25 to swing into its various positions incidental to the dwell of the die.

part 2 serves during the.

As crank 28 continues its rotary movement in a clockwise direction from the full line position of Fig. 2, stud roller 41 rides freely on the dwell 37 ofcam 29 and stud roller 33 moves towards the outer end of the slot 34 in connecting rod 25. Because of the pin-and-slot connection between crank 28 and connecting rod 25, no movement is imparted to movable die part 2 until stud roller 33 reaches the righthand end of slot 34 and stud roller 41 passes from dwell 37 onto the arcuate portion 30 of cam 29. Until this occurs, and in fact throughout the entire dwell period, movable die part 2 is locked in closed position by its operating mechanism against any pressure tending to open the die.

Immediately upon the arrival of stud roller 33 in the outer end of slot 34 and the movement of stud roller 41 onto cam surface 30, a common crank and-connecting-rodconnection is formed. At this point, crank 28 is in a substantially upright position, a point at which the component of motion of the crank pin in the direction of motion of the die part is near its maximum, so that its further movement causes the movable die part to be moved to the right with a jerk, that is, to start suddenly and move at a relatively high speed. Upon the establishment of crank-and-connecting-rod connection, the rate of movement of movable diespart 2 gradually diminishes at an approximately harmonic rate until the die part reaches its iull open position, shown in full lines in Tu theiull open position of the die, stud roller 33 is still in the outer end of slot 34 and remains in this position until stud roller 41 passes again into contact with dwell 37 of cam 29. Therefore, the closing movement of the die commences with approximately harmonic accelerated motion. This acceleration continues until movable die part 2 arrives approximately at its closed position. At this time, the part is moving, substantially at its maximum speed, or at least at a high speed as compared with-its rate of movement in the interval between the beginning of its opening movement and the end ing of its closing movement. It is particularly desirable in the construction illustrated to have the die close with the movable part traveling at a high rate of speed. If the movable die part were traveling comparatively slowly as it closes against the stationary die part, it would often fail to seat tightly. This might be occasioned by binding of die carriage on its guide rods,8, 9, or by the resistance offered by cores or the like located in the cavity 3 of the die. Closing the die with the movable part 2 traveling at a high speed causes the parts to engage tightly and accurately.

As soon as stud roller 41 passes from cam surface of cam 29 and onto dwell 37 of the cam, as indicated in dotted lines at the bottom of Fig. 2, the dwell period begins again and, as explained above, continued rotation of crank 28 does not effect any fur,-" ther movement of movable die part 2. Stud roller 41 again rides freely on dwell 37 ofthe cam, while stud roller 33 moves inwardly 1. In a die casting machine, the combination of a pair of co-operating die parts adapted to form a mold, means for moving one of said die parts towards and from the other for closing and opening the mold, and means for causing said movable die part to dwell in its closed position and to begin its opening movement and end its closing movementabruptly' with sudden transition to or from approximately its maximum speed of motion.

2. In a die casting machine, the combination of a pair of cooperating die parts adapted to be brought together for forming a casting and opened for removing the casting, and means for closing and opening the die, so that the ending of the closing movement and the beginning of the opening movement thereof occur abruptly with sudden transition from or to approximately its maximum speed of motion.

The combination in a die casting machine of a pair of co-operatmg die parts adapted to form a mold, means for moving one of said die parts towards and from the other to close and open the mold, and means for causing the opening movement of the mold to begin suddenly and at relatively high speed and then gradually decelerate to rest.

4. In a die casting machine, the combination of. a die part mounted for reciprocation from an open toa closed position and vice versa; power operated means forrec'iprocating said die part; and means for causing the opening movement off said die part to begin suddeply and at high speed and gradually decelerate as it approaches its full-open po-' sition,'said means also serving to cause a dwell of said reciprocable die part in it's closed position.

5. The combination in a die casting machine of a multi-partdie, one of said parts deceleration as it approaches its limit and being movable to open and close the die; then abruptly terminates; and a yieldable means for supporting and guiding the movconnection between the movable die part and able die part; means for driving the movits driving means.

' .eble die pert, said driving means serving to In testimony whereof I have signed my operate the movable die part so that its 0105- name to this specification. ing movement continues without substantial TORBJORN CONRAD KORSMO.

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