US2484344A - Die casting machine - Google Patents

Description

Oct. 1l, 1949.

S. HILLER ETAL DIE CASTING MACHINE 9 Sheets-Shet 1 Filed sept. '7, 1942 y` Hiller Jr.

.da M T m w.

.Han/cy H//ler ATTORNEY Oct. 1l, 1949. s. HILLER ErAl.

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9 Sheets-Sheet 3 Filed Sept. 7, 1942 r. J. J m r r M WH! H 0 m H w @ym A n n 55 Y B NF Q QS S `V NN Q E N Oct. 1l, 1949. s. HILLER E TAL 2,484,344

DIE CASTING MACHINE Filed sept. 7, 1942 y l 9 sheets-sheet 4 :E I E 71- l2 34 e 34 LZ.

ZI Z3 Z /9 INVENTORJ. 5+an/ey Hiller By .Sanley Hl//er Jr.

ATTORNEY Oct. 11, 1949.

s. HILLER Erm.

DIE CASTING MACHINE 9 Sheets-Sheet 5 Filed Sept. "7, 1942 m m n m -J'an/ey Hiller BY l .Sfahley H/l/er Jr.

AI'TORNEY. n

Oct. 1l, 1949. s. HILLER ErAL l 2,484,344

DIIE CASTING MACHINE Filed Sept. 7, 1942 9 Sheets-Sheet 6 |NVENTRs 5+an ley Hiller ATTORNEY Oct. ll, 1949. s. HILLER Erm.

DIE CASTING MACHINE 9 Sheets-Sheet 7 M rr f ,u HH n Y 55 Filed Sept. 7, 1942 ATTORNEY.

Oct. 1l, 1949. s H|| ER E TAL 2,484,344

DIE CASTING MACHINE Filed sept. v, 1942 9 Sheets-Sheet 8 INVENTORJ. .5+an/ey Hl//er .San/ey Hl//er Jr.

, ATTORNEY.

Ot 11 1949. s. HILLER Erm.

DI CASTING MACHINE 9 Sheets-Sheet 9 Filed sept. 7, 1942 v INVENTORS ATTORNEY Aline 3-3 in Fig. 1.

hasta! oef. 11, i949 DIE CASTING MACHINE Stanley Hiller and Stanley Hiller, Jr.,

Berkeley, Calif.

Application September 7, 1942, Serial No. 457,544

1 Our invention relates to a die casting machine, and more particularly to a machine for forming a solid impression from non-ferrous metals such as aluminum, zinc, magnesium and their alloys, land brass. y

Present commercial machines for forming a solid impression from metals, of the character pointed out, are incapable of forming relatively large size castings because they do not have sufilcient strength to withstand the tremendous 4 Claims. (Cl.` 22-68) stresses which are created when the metal to be cast is subjected to pressure by a ram in such vmachines. This is so because the resultant pressure applied by the ram increases with the size of the casting. Furthermore, such commercial machines drive the ram by hydraulic pressure, which is undesirable because of the yielding character of the hydraulic means for moving the ram, which may result in the casting not being compacted, thus causing formation of blow holes. This problem is particularly aggravating with respect to the die casting of aluminum, and its numerous alloys now commercially available, because of the rapidity with which such metal solidies in the die mechanism of the machine when it is subjected to pressure by the ram.

Our invention is designed to overcome the above described diillculties encountered in present die casting machines, particularly those for the die casting of aluminum and its alloys, and has as its objects, among others, the provision of an improved machine of the character described which is capable of withstanding high stresses and is therefore capable of forming relatively large castings; is of such character as to cause the casting to have a dense and compact structure substantially free of blow holes; is of relatively simple and economical construction; and is semi-automatic in its operation. Other objects of our invention will become apparent from a perusal of the following description.

Referring to the drawings:

Fig. 1 is a side sectional elevation of the machine of our invention; parts being broken away to illustrate the construction more clearly.

Fig. 2 is a section taken in a plane indicated by line 2--2 in Fig. 1.

Fig. 3 is a section taken in a plane indicated by Fig. 4 is an end elevation looking in the direction of arrow 4 in Fig. 1; a portion of the struc-` ture being shown broken away and in section to illustrate it more clearly.

Fig. 5 is a fragmentary longitudinal sectional view of the die mechanism oi' our machine.

Fig. 6 is a fragmentary longitudinal sectional view of a portion of the movable die structure appearing in Fig. 5, illustrating ejector mechanism in such die structure, in a diiierent position from that in which it appears in Fig. 5.

Fig. 7 is a fragmentary longitudinal sectional elevation of the die mechanism, in itsclosed position for formation of the impression.

Fig. 8 is a view similar to Fig. 7 with the dies apart, but illustrating a different means for handling the metal to be cast.

Fig. 9 is a fragmentary longitudinal sectional elevation of the ram and its driving mechanism forming part of our machine.

Fig. .10 is a plan view, looking in the direction of line Ill-I0 in Fig. 9; parts being shown broken away and in section to illustrate more clearly the construction.

Fig. 11 isa section byline iI-Ii inFig. 9.

Fig. 12 is an end elevation looking in the direction of arrow l2 in Figs. 1 and 9.

Fig. 13 is a schematic view of our machine, and the wiring diagram for causing semi-automatic operation thereof.

Fig. 14 is a fragmentary longitudinal section illustrating a preferred form of lost motion drivtaken in a plane indicated ing means for moving the movable die structure forming part of our machine.

Fig. 15 is a section taken in a plane indicated by line lS-IS in Fig. 14.

Fig. 16 is a section taken in a plane indicated by line Iii- I6 in Fig. 14.

Fig. 17 is a sectional view illustrating the driving mechanism of Fig. 14 in developed form.

With particular reference to Fig. 1, the machine of our invention comprises die mechanism including a stationary die structure `2 and a movable die structure 3, slidable toward and away from stationary die structure 2. Die structure 2 includes a plate rigidly supported on a pair of spaced foundation members, preferably in the form of beams I, by means of a suitable bracket structure 6 secured to beams 4 by bolts 1. Also rigidly secured to beams .I at the left of stationary die structure 2, with reference to Fig. 1, are a pair of spaced plate members 8 and 9; and at the right of stationary die structure 2 and spaced therefrom is a plate member Il rigidly secured to beams l; movable die structure 3 being slidable between plate il and stationary die structure 2.

Means is provided for rigidly tying plate mem- -bers 8, 8 and Il, and stationary die structure 2, against axial displacement to provide a rigid frame unit. With reference to Figs. l, 5 and 9.

such meanscomprises a plurality of screw threaded shafts or rods I2, each of which has a shoulder I3 adjacent its right end abutting one side of plate I I, and a reduced end portion I4 projecting through plate I I. upon which is screwed a nut I3 for clamping plate II betweenthe nut and shoulder I3. Such reduced end portion I4 of rod I2 is formed with a non-circular portion' I1 to enable the rod to be turned by a suitable tool, for a purpose to be subsequently explained. The opposite end portion of each of rods I2 is formed with a shoulder I8 engaging a side of stationary die plate structure 2, and with a reduced screw threaded portion I8 which projects through die structure 2; a clamping nut 2l on reduced portion I9 clamping shoulder I8 against die structure 2.

Screwed in the end of each portion I8 of each rod I2 is a second rod 22 which projects through suitable apertures in plates 8 and 9; a spacer sleeve 23 about each rod 22 being interposed between plate 8 and the left end of the associated rod I2; while another spacer sleeve 24 is interposed between plate 8 and plate 8. Each rod 22 extends beyond plate 8 and on the projecting end thereof is a clamping nut 26 which, when tightened against plate 9, rigidly maintains plates 8 and 9 in proper spaced relationship with respect to each other and with respect to stationary die structure 2.

Movable die structure 3 comprises a plate member 21, and a second plate member 28 spaced therefrom but rigidly connected thereto by means of elongated cap screws 28 and spacer sleeves 3| interposed between plates 21 and 28. The space 32 between plates 21 and 28 provides an enclosure for driving mechanism 33 for the purpose of sliding the movable die structure toward and away from stationary die structure 2; a plurality of cover plates 34 being detachably secured to the edges of plates 21 and 28 for covering driving mechanism 33. The entire die structure 8 is slidable over the threads of rods I2; suitable bearing sleeves 36 being supported in plate 21 to facilitate riding of such movable die structure 3 over rods I2.

'I'he driving mechanism 33 comprises a walking nut 31 screw threaded on eacl of the threaded portions of each rod I2, and which is positioned between plates 21 and 2B; a thrust washer 38 being interposed between each walking nut 31 and plate 21. The aperture in each thrust washer is of larger diameter than the outside diameter of the threaded portion of rod I2, and such washer is seated in a recess formed in the associated nut 31; so that the washer will not engage the threads. When walking nuts 3'1 are rotated in a clockwise direction with reference to Fig. 5, they will move axially and engage plate 21 of the movable die structure to slide such structure toward stationary die structure 2; and when such walking nuts are turned Ain an opposite direction, they will engage plate 28 of the movable die structure to move it away from stationary die structure 2.

Means is provided for rotating walking nuts 31, and thereby effecting axial movement thereof, comprising a pinion 38 keyed to a shaft 4l. and which is located between plate 21 and a collar 42 fastened to plate 28; a thrust washer 43 being interposed between a shoulder 44 on shaft 4I, and plate 21. The inner end of shaft 4I is piloted in a suitable bearing 45 mounted in plate 21; while the outer end of shaft 4I extends through an aperture formed in plate II and has a lost motion driving mechanism 41 mounted thereon which will be subsequently explained in greater detail. Meshing with pinion 38 and gear teeth 48 formed on, walking nuts 31 are a plurality of idler gears 49, each of which is freely journalled about a shaft 50 secured in plates 21 and 28. Thus, it is seen that rotation of shaft 4l in either one or of opposite directions will result in sliding of movable die structure 3 in either one of opposite directions. In this connection, by loosening nuts I5 and 2| and turning rods I2 by engaging portions I1 with a suitable tool,l adjustments can be made to insure that the parts of driving mechanism 33 will be in proper alinement.

Means is provided to relieve as much as possible the load of movable die structure 3 on rods I2, and thereby minimize possible binding of walking nuts 31 on the screw threaded portions pf rods I2, which might result from flexing of the rods under too great a load. Such means comprises a pair of spaced rails 5I upon which the bottom of movable die structure 3 can slide; suitable bearing shoes 52 being mounted on die structure 3 to ride on the rails 5I. Each of rails 5I is supported for vertical adjustment to enable vertical adjustment of movable die structure 8 with respect to rods I2 so that the die structure may be properly positioned and hence slide freely over the rods.

For this purpose, the left end of each rail 5I, appearing in Fig. l, is adjustably securedvto a bracket structure 53 rigidly supported on stationary die structure 2, and having elongated slots 54 through which pass fastening cap screws 56 screwed in the rail and which are adapted to be tightened against bracket structure 53 to clamp the rail against the bracket structure; the lower edge of the 4rail being supported on an adjustable set screw 51 screwed in a bracket f 58 also rigid, with stationary die structure 2.

A. locking nut 58 is provided to hold set screw 51 in adjusted position. The right end of each rail 5I is similarly adjustably supported on plate member II, by means of cap screws 6I which pass through elongated slots 52 in the rail, and a set screw 63 for supporting the lower edge of the rail. Thus, the adjustment of each rail 5I can be readily made by loosening cap screws 56 and 6 I, and adjusting theset screws 51 and 83.

Means, including the lost motion driving connection 41, is provided for transmitting a. drive in either direction to the driving mechanism 33 which is supported by movable die structure 3. Secured to the outer side of plate II isa bearing 64, through which shaft 4I extends, and upon which is journalled a pulley 66 which is held against axial displacement by a thrust collar 61 fastened to the rightend of bearing 84 with reference to Fig. 5. Such pulley 66 is adapted to be rotated in either one of opposite directions by reversible electric motor 68 which is connectedl to the pulley through multiple belt driving connection 69. To enable proper adjustment of the tension on belt connection 58, motor 58 is supported for vertical adjustment; being mountedon a support 1I which has one end pivoted, at 12. to a bracket structure 13 secured to one of beams 4. The opposite end of support 1I is pivotally connected to a bolt 14, which passes loosely through the other beam 4 and is adapted to be adjustably held in position by nuts 16. By

loosening such nuts 18, the vertical position of motor may be readily adjusted through movement oi' support 1| about pivot 12.

A drive from pulley 66 is transmitted. in either direction, to shaft 4| and consequently the driving mechanism 33, by means of a hub 11 which is secured for rotation with shaft 4| but which is so mounted -on the shaft by a suitable slot and key connection -13 as to permit slidable movement of shaft 4| through hub 11 during rotation oi' these members. Hub 11 is connected to be rotated from pulley 66, by means of a pair oicap screws Il secured to pulley 66, each oi which is adapted to engage either side of opposite lugs 02 projecting from diametrically opposite points on hub 11 and which result from the formation of arcuate slots 03 in hub 11. Axial displacement of hub 11 with reference to pulley 69 is precluded by washers 94, which are held in position by the cap screws 9| and which overlap hub 11.

From the preceding, it will be noted that after movable die structure 3 has been moved in one direction, by the driving means, and it is desired to move it in an opposite direction, cap screws 0| must travel through slots 83 before they engage lugs 02 to cause rotation of shaft 4| and operation of the driving mechanism 33. Such lost motion insures that motor 68 will get up to full speed before walking nuts 31 are turned, which is important because there may be slight binding of such nuts on the rods |2; and if the motor il were not able to develop its full power before the drive to the nuts 31 is effected, it might not be able to turn the nuts readily, resulting in undesirable strain.

The movable die structure 3 has mounted thereon a die member 9| which is adapted to cooperate with another die member 92 on stationary die structure 2; so that when movable die structure 3 is moved to the position wherein the die members 9| and 92 are in engagement or closed, as is shown in Fig. 7, an impression or casting 93 of material may be formed in the die space when subjected to pressure by a movable ram member 94. Means is provided for detachably mounting each of die members 9| and 92; and the mounting means for the die member 9| on the movable die structure 3 is of such character as to enable the employment of ejector mechanism for automatically removing casting or impression 93 from the die when the movable die structure 3 is moved away from stationary die structure 2 after the casting is formed.

Die member 9| is provided with grooves in oppositeedges thereof in each of which is engaged one leg of an L-shaped clamping member 90; spacer blocks 91 being interposed between die member 9| and plate 21 of the movable die structure. The other leg of each clamping member 96 is held against plate 21 by cap screws 98 which are Vscrewed into plate 21. Die member 92 is similarly secured to the stationary die structure 2 by means of clamps 99 and cap screws |0I. As a result of the described mounting of the dies, they may be readily detachably mounted on or removed from their supporting structures to enable various shaped dies to be employed in accordance with the character of impressions or castings desired.

'I'he ejector mechanism for ejecting the casting or impression 93 from die 9| comprises a plate |02 slidably mounted in the space between die 9| and plate 21 of movable die structure 3. Fixedly secured to plate |02 are a plurality of pins |03 which extend through die 9| `so as to lstationary plate Il of s be slidable therein. Some of such pins are opposite the die recess space formed between dies 9| and 92 in their closed position, and are of diierent lengths to accomodate the lshape of casting or impression 93 formed in such space. Other ofv such pins, the outside pins with reference to Fig. 3, are of the same length; and in the closed position of the dies, they are adapted to engage the outer planar face |03' of die 92 to thrust plate '|02 against plate 21 of movable die structure 3. Extending loosely through movable die structure 3 and carried thereby so as to be axially slidable relative thereto, is a rod |04 which is adapted to abut at one end against posite end, rod |04 is adapted to engage plate |02. Such rod |04 is of a predetermined length less than the distance between plate I| and the position which plate |02 assumes in the closed position of the dies, as is illustrated in Fig. 7.

In the closed position of the dies, all of pins |03 are of such length so as not to p roject beyond the die surface of die 9|. After formation of the impression or casting 93 and movement 0f the movable die structure 3 away from stationary die structure 2, casting 93 will be automatically ejected from die 9| when one end of rod |04 engages plate Il and the ejector plate |02 strikes the opposite end of the rod, which will occur substantially at the position movable structure 3 has in the fully open posltion'of the dies. This results in movement of ejector plate |02 from the position shown in Fig. 5 to the position shown in Fig. 6. In this connection. it is to be noted that the plug |05 of impression 93 is wedged slightly in die 9| so that it will not stick in die 92 when the dies are separated, the wedging being not great enough to preclude an ejector pin |03 located opposite plug |05 from forcing the plug from die 9|.

When ram 94 is moved to apply pressure on the material in the dies when they are closed, extremely high pressures are set up. It is to be noted, however, that the construction of our machine is such as to withstand ably such high pressur because a large part of the thrust is taken up by walking nuts 31 which abut plate 21, and are closely adjacent the dies themselves in the closed position thereof. As a result, rods I2 will be placed under tension for a short distance between plate 21 and stationary structure 2. Our machine avoids a lengthy linkage system in association with movable structure 3 which would be placed under compression, as occurs in present comercial machines. Thus, our

machine obviates bending strains which Vexist in machines employing such linkage system.

For the formation of impression 93 in the closed position of the dies 9| and 92, molteny 'material may be poured through a. funnel member |06 secured to a sleeve |01 extending through and rigidly mounted in stationary structure 2. Sleeve |01 communicates with an aperture |03 in die 92 to enable the material poured into the funnel member |06 to be'forced between dies 9| and 92 by the ram 94 when the dies are in their closed position. The rigid mounting of sleeve |01 is effected by die member 92 which clamps a flange |09 formed on sleeve |01, against stationary structure 2; the flange |09 being seated in a recess in such structure 2. An annular space I is preferably provided in structure 2 about sleeve |01, to house which are adapted to be energized to supply heat for preventing cooling of the material before it the machine. At its opelectric heating coils H2 -by a plate ||3 secured to stationary structure 2 by cap screws ||4.

Some materials, such as many of the aluminum alloys available on the market, may be more advantageously cast if they are not in molten condition but in a semi-molten state, where the metal is at a temperature slightly below its melting point. When it is desired to treat metal in this fashion, funnel member |88 may be omitted; and a block of the metal at the desired tem.- perature may be inserted directly through an aperture in a sleeve ||8, as is indicated in Fig. 8. This method of casting has the advantage of minimizing the formation of blow holes, which might occur by escape of gases from molten metal subjected to the ram pressure.

Movement of the ram in the machine of our invention is effected by mechanical non-hydraulic driving means including an energy stor1 ing member in the form of a ywheel. This has the advantage, when the casting is being formed, of placing a constant pressure on the material, which results in the casting being formed with minimum blow holes; particularly since the ram may be moved rather slowly to apply pressure on the material, thus giving a chance for gases to bleed out of the material during the time it is solidified to a solid mass. The advantage of the mechanical non-hydraulic drive for the ram, in the form of its flywheel control, can not be obtained in hydraulic machines because of the yielding action which occurs where fluid power is employed to move the ram for applying pressure on the material.

With reference to Figs. l, 9, 10, 1l and l2, ram 94 comprises a hollow member i2| which is screw threaded in a screw member |22 having screw threads |23 thereon, which cooperate with a rotatable nut |24 held against axial movement. A longitudinally extending baille |26 is provided in the hollow portion of ram member |21|; and cooling water is preferably circulated through such hollow portion, around baille |26, by means of flexible piping |21, so as to keep the ram relatively cool as it works through the dies. Rotation of nut |24 will result in feeding of ram 94 either toward or away from the dies, depending upon the direction of rotation; and means is provided for confining the ram to longitudinal movement upon rotation of the nut.

Such means comprises guide rail |28 rigidly secured in the space between stationary die structure 2 and plate 8, with which is engaged a guide shoe |29 held on member |2| of ram 94 by a nut |3| screwed on such-ram member |2|. Nut |3| clamps shoe |29 against screw member |22 of ram 94, and consequently holds the shoe and ram members |2| and |22 rigidly together. To preclude turning of guide shoe |29, it is provided with locking lugs |32 engaging in recesses formed in the adjacent end of screw member |22; the lower end of shoe |29 being recessed at |33 to receive rail |28.

Adjacent one end, nut |24 is journalled in a bearing sleeve |34 rigidly secured to plate 8 by 4 suitable means such as welding |36; a thrust washer |31 being detachably secured to bearing |34 to preclude axial movement of the nut in one direction. At its opposite end, nut |24 is journalled in a bearing |38 rigidly secured to plate 9 by suitable means such as welding |39; suitable bushings |48 being interposed between vthe outer peripheral surface of the nut and bearings |34 and |38.V A plate l4|, detachably'secured to bearing |33, holds the nut against axial movement in an opposite direction.

Journalled for both rotational movement about nut |24 on a bushing |42 about the nut, and for axially slidable movement along the nut, is a flywheel |43 adapted to be rotated in either one of opposite directions from reversible electric motor |44, through a multiple belt drive connection |45 between the motor and the flywheel; the motor being provided with an adjustable mounting |46, similar to the mounting for motor 68, to enable adjustment of the tension on belt drive connection |45. Secured to the left side of the flywheel, as it appears in Fig. 9, is a clutch element |41, the teeth of which are adapted to be moved into engagement with and out of engagement from cooperating teeth on a complementary clutch element |48 which is screwed on nut |24. and locked thereto by a locking pin |49 insertable through a longitudinal recess |58 formed in the outer surface of nut |24. Clutch element |48 is held against axial displacement with respect to nut |24, by being positioned between a shoulder formed on the nut, and a thrust plate I5| located between clutch element |48 and plate 9; the latter being preferably provided with reinforcing ribs |52 on its outer side.

When the flywheel is rotated, engagement of clutch elements |41 and |46 will result in turning of the nut in either one of opposite directions depending upon the direction of rotation of the flywheel by motor |44. Means is provided for connecting or disconnecting clutch elements |41 and |48, to establish or interrupt a drive between flywheel |43 and nut |24, comprising movable clutch collar or yoke member |54 having shoe means |56 adapted to engage freely in a peripheral groove |51 formed in the hub of the flywheel. Yoke member |54 is normally spring thrust by resilient connections |58 to maintain disengagement of clutch elements |41 and |48;

For the purpose of effecting lengagement of such clutch elements, yoke member |54 is pivoted at |59 to a bracket |60 rigidly secured to plate 3; a downwardly extending lever |6 being rigidly connected to yoke member |54. As a. result, when lever |6| is moved to the right, with reference to Fig. 9, by actuating a rod |62 pivotally connected to lever |6|, clutch elements |41 and |48 will become engaged to transmit a drive from flywheel |43 to nut |24. Actuation of rod |62 to effect the described clutch engagement is preferably effected by an electrically operable solenoid |63 of any suitable construction. Upon energization of the solenoid, through any suitable electric control, the drive will be established, but when the solenoid is (ie-energized, resilient connections |58 will interrupt the drive by automatically effecting disengagement of the clutch elements.

In operation, the drive between flywheel |43 and nut |24 is manually established only after the motor |44 has been brought up to full speed. This enables the ram to be driven after initiation of rotation of the flywheel; and as a result, suilicient energy will be stored in the flywheel to cause it to apply the desired constant pressure on the ram 94 for effecting the desirable solid casting with minimum formation of blow holes. In this connection, motor |44 is associated with a conventional form of solenoid operated brake |64, which becomes automatically engaged when the motor is de-energized and is automatically released upon energization of the motor.

The weight of flywheel |43 and the speed of and light impact force on the material, a relatively light flywheel rotating at a relatively slow speed should be utilized. A relatively heavy ilywheel rotating at a relatively high speed will cause a relatively fast stroke of the ram, with a relatively heavy impact force on the material; while a fast stroke of the ram and alight impact force on the material will obtain by the provision speed. Thus, it is seen that the ilywheel controlled ram in the machine of our invention is an important factor in obtaining desired characteristics in the formation of the casting or impression. l

As was previously related, when the dies 8| and 82 are closed and ram 94 is moved to form the casting or impression 98 in the dies, walking nuts 81 receive the thrusttransmitted through movable die structure 8. Such thrust is very high; and as a result the walking nuts may bind on cult to loosen the nuts simultaneously when it is desired to move movable die structure 8 so as to separate or open the dies. even with the lost motion driving mechanism 41. We, therefore, preferably employ a driving gear arrangement in as. sociation. with the walking such nuts to be loosened individually, when it is desired to move movable die structure 8, to separate the dies after ram 98 has formed the cast- Figs. 14, 15, 16 and 17 illustrate such preferred form of driving gear arrangement in which the movable die structure comprises a plate |1| having inner reinforcing ribs |12 integral therewith, and upon the outer side of which is mounted die member |13 of the same character as die member 8|. Spaced from and rigidly secured to plate |1| by means of cap screws |14 and spacers |18 is another plate |11, which in cooperation with f ,nailed on stub shafts |81 secured to plate 11;

the idler gears |86 meshing in turn with drivable gears |88 for walking nuts |89 each of which is screw threaded on a threaded rod I2. Asin the previously described modification, four walking nuts |88 are employed; and consequently, the driving mechanism includes four of the drivable gears |88.

As can be observed more clearly from Fig. 14, each of the drivable gears |88 is journalled for rotation about an associated threaded rod |2 but not in contact therewith, by means of a hub portion |8| journalled in a bearing sleeve |92 tlxedly l0 secured to plate |11 by any suitable means such as welding. Gear |88 is held against axial displacement by a thrust washer |88 detachably secured to hub |8| and engaging one end of sleeve |82, and by a shoulder |88 which engages the opposite end of such sleeve. Projecting axially from the inner face oi' each gear |88 is a driving. lug |88 adapted to engage the faces |81 of lug means |88 formed on walking nuts |88. Thus, rotation of each drivable gear |88 in either one of opposite directions will result in a corresponding rotation of the associated walking nut |88, through engagement of the associated lug |88 with a face 81.

The spacing between faces |81 on each walking the width 0i' an assonut in cooperation with elated driving lug |98, and the spacing between each gear |88 and the associated -walking nut |88, are such as to cause the walking nuts to become loosened individually from threaded rods l2, when the movable die struct-ure is moved to separate theV dies after the casting operation. Thus motor 68 will be able to apply its i'ull power to loosen the w-alking nuts one at a time should nuts which enables they by chance happen to bind on the associated threaded rods l2 as a. result of the pressure applied against them during the casting operation.

With particular reference to Fig. 15 and the developed view of Fig. 17, on each of which views the pairs of walking nuts and associated gears |88 are indicated .by the respective reference letters A, B, |88 and the xassociated nut at A are locked together with respect to relative angular movement, because lug |96 is in con-tact with both lug eng-aging faces |91 on the Iassoci-ated walking nut. 'Ihese ilgures illustrate the position which the parts of the driving mechanism have when the movable die structure is being moved to close the dies; and in Fig. 15, the direction arrows indicate the direction of rot-ation ofthe -pairs of walking nuts and gears when the movable die structure is being driven toward die closing position. It will be noted that there is a relatively wide axially extending space |98 between the adiacent faces of the walking nut |89 and the assoelated gear |88, at A, which are adapted to abut.

The walking nut and the associated driving gear at B have a narrower axially extending space 28| between them; while the angular spacing between the left lug engaging face |81 on the nut at B'in Fig. 15, and the cooperating face on lug |98 adapted to engage such face |91, is 90, which is the distance that lug |96 must be turned in an opposite direction of rotation, when it is de sired to effect axially abutting engagement between the walking nut and the driving gear so as to move the walking nut in an opposite direction for moving the movable die structure Iaway from the closed position of the dies.

Axial space 202 between the walking nut and the associated gear at C is still narrower; while as indicated in Fig. 15, the distance which lug |86 on the gear at C must be moved angularly in an opposite direction of rotation, before iangular engagement of the associ-ated walking n-ut and gear can obtain, is

At D, the walking nut and associ-ated driving gear are in axial abutment; while the angular spacing referred to with reference to the B and C positions of lugs |86, is 270.

The parts of lthe driving mechanism on the movable die structure, will assu-me the position shown in Fig. l5 after the dies are closed and the movable die structure is at rest. After the cast- C and D, it will be noted that the gear ing is formed and separation of the dies is to be ell'ected, .the walking nuts and gears must be rotated in a direction opposite to that indicated by the direction arrows in, Fig. l5. Since the walking nut and the associated drivable gear at A are in permanently locked position with respect to relative angular movement, and since the lugs |96 of the drlvable gears |88 at B, C and D must be rotated a predetermined angular distance before they will angularly eng-age the cooperable faces |91 on the associated walking nuts, when motor 68 is rotated in a direction to open the dies, it will be observed that the walking nut at A will be the only walking nut that will .be turned at first; and consequently, should it become bound it will become very readily loosened.

After 90 of rotation, the walking nut at B will be caused to become turned together with the walking nut at A; and after an additional 90 of rotation, the walking nut at C will be turned together with the walking nuts at A and B. Finally, after an -additional 90 of rotation, Athe walking nut at D will be rotated. By virtue of the axial spaces |99, 20| and 202 between the respective walking nuts and gears at A, B and C, driving engagement between the walking nuts and associated gears, in an axial direction along the respective threaded shafts 2 will not occur, until all of the walking nuts have Ibeen loosened. When this occurs the driving engagement in an axial direction to move the movable die structure away from the die closed position will simultaneously be eil'ected among the various associated walking nuts and gears because space |99 is such as to be equivalent to 270 of rotation of the associated walking nut on the associated threaded rod; space 20| is equivalent to 180 of rotation with reference to the same parts; and space 202 to 90 of rotation. When the movable die structure is stopped after operation of the dies, the reverse effect will obtain.

From the preceding, it is seen that the preferred driving means for the walking nuts provides a lost motion connection for each of such nuts, in addition to main lost motion driving connection 41. Also, such driving means rst eiects successive rotation of the nuts to loosen them individually. Then, such driving means effects simultaneous movement of the nuts axially along threaded rods I2 to slide the movable die supporting structure over such rods.

Electrical means is provided for semi-automatic operation of the machine of our invention. In this connection, all of the electrical parts are of conventional construction adapted to be energized from a main power line 2 0, and are hence merely schematically shown in Fig. 13. Motor 68 is a conventional reversible drive motor; while motor |44 is of a conventional reversible drive type having the previously mentioned solenoid operated brake |64 which is automatically applied when the motor is not running and which becomes automatically released upon energization of the motor.

A plurality of limit switches are provided on the machine for controlling automatic operation of the motors, and consequently automatic operation of the movements of the movable die structure 3 and ram 94. Limit switch 2li is of the open type normally held open by a spring 2||'; and is adapted to be automatically closed by one end of a control rod 2|2 mounted on the movable die structure 3, to start motor 44 in the direction for moving ram 94 toward the dies 9| and 92, after movable die structure 3 is moved -to the position where such dies are closed. In'

this connection, motor 68 for moving the movable die structure is associated with an overload circuit breaker 2|3 which stops the motor upon closing of the die members 9| and 92. A limit switch 2|4 which is normally held open by a spring 2|4, is adapted to be closed by the opposite end of rod 2 I2 when movable die structure 3 is moved away from die closed position, to start Vmotor |44 in an opposite direction from that for moving ram 94 toward the dies, so that the ram may be moved away from the dies; while a limit switch 2|6, which is normally held closed by spring 2|6', is adapted to be opened by such opposite end of rod 2 I2 to stop motor 68.

Movable with ram 94 is a switch control rod 2|1 having secured thereto a collar 2I8 which, after ram 94 has been moved to force the material in between the closed dies 9| and 92, opens a limit switch 2 |9 normally held closed by a spring 2| 9' to stop motor |44 and thus stop movement of theram in one direction. Movement of the .ram in an opposite direction, when it is moved away from the dies after the casting operation, is automatically4 effected by engagement of collar 2|8 with limit switch 22| normally held closed by a spring 22|'. After starting of the motor |44 in the direction for moving ram 94 toward the closed dies, movement of such ram is effected manually by push button switch 222 which, as long as it is manually depressed, will eect energization of solenoid |63 to eiect engagement of the clutch |41, |48. When switch 222 is released, the solenoid will be automatically de-energized, to allow release of such clutch by the resilient means |68.

In the inactive or idle position of the machine, movable die structure 3 has a predetermined neutrai position remote from the position which it has when the dies are closed; and to start the motor 68 for feeding the movable die structure toward die closing position, a push button switch 223 is provided which, when manually depressed and immediately released, will energize a circuit for causing rotation of motor 68 in the direction for moving the movable die structure toward the left with reference to Fig. 13; and such circuit will remain energized through solenoid controlled double switch 224 until it is broken by overload circuit breaker 2|3 when the dies 9| and 92 close.

A second push button switch 226 is provided to energize a circuit for reverse flow of current through motor 68 for moving movable die structure 3 in an opposite direction away from die closed position; such circuit remaining energized by solenoid controlled double switch 221. Should it be desired to stop movable die structure 3 in an intermediate position, for emergency purposes, in any direction of movement thereof, the circuit through motor 68 may be interrupted by emergency switch 228.

A jog switch 229 is provided, which will only energize a circuit through motor 68 as long as it is held depressed, to permit motor 68 to move the movable die structure 3 any predetermined extent toward die closing position; such circuit being through the coil of switch 224. A similar jog switch 23|, which controls a circuit through the coil of switch 221, is provided to energize the motor only as long as it is manually depressed, to cause movement of the movable die structure 9 any predetermined extent away from die closed position.

Manual control of motor |44 for moving ram' 94 toward and away from material casting position may be optionally effected, if desired, by

switches 232 and 233, respectively, which control circuits through respective solenoid controlled double switches 234 and 236, and are of the type which need be only manually depressed and released for energizing such circuits; an emergency cutout switch 231 being provided to break the circuit through motor I in case this is necessary. In this connection, an overload circuit breaker 238 is provided to break the circuit through motor I in case it becomes overloaded as a result of too much material being in the dies, thus placing too great a stress on the ram. Jog switches 239 and 24|, similar in operation to jog switches 229 and 23|, are provided to enable limited movement of the ram in either direction in case this is desired. The switches for controlling ram motor I are seldom used because of the controls provided by the limit switches 2| I, 2|I, 2I9 and 22|, but are merely present to be employed for manual operation, if desired. i

In operation, movable die structure 3' has a position spaced from stationary die structure 2, in the idle position of the machine; and when it is desired to close the dies, the operator need only depress switch 223. As soon as the dies 9| and 92 are closed, overload circuit breaker 2| 3 stops the motor 88. Also limit switch 2II will be closed by rod 2I2 to start motor |44 in the direction for moving ram 94 toward material casting position. However, the ram will not be moved until clutch control switch 222 is manually held closed. In the meantime, the operator will feed material into the dies through funnel |06. As soon as the ram is moved to its fullest extent toward material casting positionlimit switch 2I9 will be operated to open the circuit through motor I to stop the motor, whereupon clutch control switch 222 may be released.

After the impression is formed by dies 9| and 92, they are separated by pushing switch 226, which results in rotation of .motor 08 in a direction for movement of movable die structure 3 away from stationary die structure 2. When rod 2 I2 hits limit switch 2 I6, motor 68 will be stopped to stop the movable die structure 3. At the same time. rod 2I2 will hit limit switch 2H, which will en'ect starting of motor I in a direction for moving ram 94 away from material casting position; and when collar 2I on rod 2I'I hits limit switch 22|, motor |44 will be stopped, thus rendering the machine ready for its next cycle of operation. Should it be desired to control ram Il entirely by manual operation, the limit switches associated therewith need not be employed.

We claim:

1. In a machine ot the class described, die mechanism, a ram for forcing material into such die mechanism and having screw threads thereon; and driving means for moving the ram including a rotatable nut cooperable with the threads, means restricting axial movement of the nut, a rotatable flywheel, and mechanism enabling establishment of a drive between the ilywheel and the nut after initiation of rotation of the fywheel.

2. In a machine of the class described, die mechanism, a ram for forcing material into such die mechanism and having screw threads thereon; and driving means for moving the ram including a rotatable nut cooperable with the threads, means restricting axial movement of the nut, means for coniining the ram to longitudinal movement upon rotation of the nut, a rotatable flywheel, and mechanism enabling establishment of a dr-ive between the flywheel and the nut after initiation of rotation of the flywheel.

3. A die casting machine for forming an impression of metal solidifiable by application of pressure comprising die mechanism, an axially movable ram for forcing material into the die mechanism and having screw threads thereon. a rotatable nut about the axis of the ram and cooperable with the-threads, means restricting axial movement of the nut, means including a power driven flywheel about the nut for rotating the nut and thereby moving the ram axially, and means cooperable with the ram to prevent turning thereof as it is moved axially.

4. A die casting machine for forming an impression of metal solidiflable by application of pressure comprising diel mechanism, an axially movable ram for forcing material into the die mechanism and having ,external screw threads thereon. a rotatable nut about the axis of the ram and having internal screw threads in engagement with the ram threads, means restricting axial movement of the nut whereby the ram will move axially upon rotation oi' the nut, means cooperable with the ram to prevent turning thereof as it is moved axially, a power driven wheel member rotatable about the axis of the nut, and mechanism enabling establishment of a drive between the wheel member and the nut after initiation of rotation of the wheel member.

STANLEY HILLER. STANLEY HILLER, JR.

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

UNITED STATES PATENTS Number Name Date 193,330 Hall et al July 24, 1877 1,249,919 Doehler Dec. 11, 1917 1,910,284 Fiegel et al. May 23, 1933 2,055,944 Polakv Sept. 29, 1936 2,172,003 Stanley et al. Sept. 5, 1939 v2,193,935 Mulcahy Mar. 19, 1940 2,214,308 Polak Sept. 10, 1940 2,233,354 Thilenius Feb. 25, 1941 2,244,123 Sebek June 3, 1941

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