US2131955A

US2131955A - Die casting machine

Info

Publication number: US2131955A
Application number: US50914A
Authority: US
Inventors: Roy F Johnson
Original assignee: IMP DIE CASTING Co
Current assignee: IMP DIE CASTING Co; IMPERIAL DIE CASTING Co
Priority date: 1935-11-21
Filing date: 1935-11-21
Publication date: 1938-10-04
Anticipated expiration: 1955-10-04

Description

Oct. 4, 1938. R. F/JOHNSON DIE CASTING MACHINE Filed Nov. 21, 1955 9 sheefssheet 1 & m e

Oct. 4, 1938. R. F. JOHNSON DIE CASTING MACHINE Filed Nov. 21, 1935 9 Sheets-Sheet 2 Oct. 4, 1938. R. F. JOHNSON DIE CASTING MACHINE Filed Nov. 21, 1935 9 Sheets- Sheet 5 Jfadeziv is fo yzfafizasvzz.

Oct. 4, 1938. R. F. JOHNSON DIE CASTING MACHINE 9 Sheets-Sheet 4 Filed Nov. 21, 1935 A QWN w Oct. 4, 1938. R. F. JOHNSON 2,131,955

DIE CASTING MACHINE Filed Nov. 21, 1935 9 Sheets-Sheet 5 a: 3412 3.51 J36 J32 fideza? gi 1229 l/OilOIZ 9 Sheets-Sheet 6 N MN QQN NW Oct. 4, 1938. R. F. JOHNSON DIE CASTING MACHINE Filed Nov. 21, 1955 9 Sheets-Sheet 8 NMW Oct. 4, 1938. r a. F. JOHNSON I 2,131,955

' DIE CASTING- MACHINE Filed Nov. 21) 19:55 9 .sheets'sheet 9 )AZMW, Jmdajif:

Patented Oct. 4, 1938 ma CASTING MACHINE Roy F. Johnson, Oak Park, 111., assignor to The Imperial Die Casting Company, ChicagoJlL, a corporation of Illinois Application November 21, 1935, Serial No. 50,914 v UNITED STATE 22 Claims. (01. 22-69) 5 now in use. I 5 Another object of my invention is to provide ssociated mechanism a d is t ken on the li e an improved die casting machine which is. 1 Figure adapted for making die castings of different Figure 7 is a sectional view showing the clutch 'metals. mechanism and is taken on the line 'I'I of 10 Another object ofmy invention is to provide i u an improved die casting machine which is eco- Figure 8 s a Se o l w f t c utch 00 nomical and efiicient i rati trol detent and is taken on the line 8-8 of Another object of my invention is to provide F gure 7; an improved die, casting machine which can be g e 9 is a Section through the ir valve used in either a horizontal or vertical or inclined S owing the partsin no P s tion and is taken 15 position. on the line 99 of Figure '1; I

Another object of my invention is to provide an re 10 is a section 01. the air valve, identical imprived die casting machine which operates at with that of Figure 9 excep that the Parts are higher pressures and makes better castings than Shown in Opposing D n; those heretofore used. I Figure is a top View Showing the core pull- 20 Another object is to provide an improved die s mechanism; casting machine which can be operated as either Figure 12 i a v l section ta en on the a fully automatic machine or as a semi-autoline of Figure 1 V magic machine I Figure 13 is an elevation, partly in section, Another object is to provide an improved die showing a modified form of "metal feeding 25 casting machine which is safer to operate and mjecting mechanism the machine ShOWn in easier to handle than the machines now in use. F1311"! a e Another object of my invention is to provide a Figure 14 is a side elevation. partly in e n. e casting machine having improved driving showing a modified form of my invention; mechanism. I Figure 15 is an end elevation of the machine 3t Another object of my invention is to provide a wn in Figure 14; a die casting machine having improved clutch con- Flgul'e 16 is a e levation, partly in section,

t mechanism; showing a further modification; and

Another object is to provide'a die casting ma- Figure 17 is a sectional View Showing a detail chine having improved casting ejecting means. the heme and is taken on the line 01 35 Another object is to provide a die castingma- Flgm'e chine having automatic core pulling means. In guns 1 thmligh 13 0f the drawing r 1 Another bje t 15 to provide adie casting have shown an embodiment of my invention h vchine having an improved valve forcontrolling mg a base comprising uprights and i the admission of air to inject molten metal into which are Secured rearward extensions and 40 the die. 26, respectively. 7 The left-hand ends of the up- Another object of my invention is to provide

rights

20 and 22, and their associated extensions improved means for preventing solidification of u and 26 are connected together as by means the molten metal in the meeting nozzle of a transverse channel. iron 28. I also provide Another object of myinvention is to provide gussets toiemmme the base" f 45 improved means for preventing the die cast metal A pair slde mus extend forwar and from interfering with the air supply. r a whlch may be any Sult- Other objects and advantages will become apg i The side rails con. parent as the description proceeds. ec ed by suitable transverse members 38, one I In the drawings of which is secured to the channel 28 by bolts 40. 50

Figure 1 is a sitie elevation partly in t1 In the present instance the furnace 36 is shown of one embodiment of m mv t1 e as attached to the rails 34 by bolts 42 although Fi y en any other suitable means may be used. L gure 2 is an end elevation looking in the 1 upper ends of the uprights 2n and n are dlreFtlqn arrow 2 of Flgure 1; yoke-shaped-and to each upright there is bolted 55 Figure 3 1s a fragmentary view showing part a pair'of guides I4 and. The guides 44 and of the mechanism shown in Figurel but view- 1 46 associated with the upright 20 slidahly reing this mechanism from the opposite side of the ceive a supporting block '48 which maybe admachme; justed by means of

screws

50 and 52. The guides f Figure 4 IS a sectional view showing the driv- 44 and 46 secured to the upright 22 My invention pertains to die casting machines. An object of my invention is to provide a new and improved die casting machine which is adapted for a wider range of work than those Figure 2;

Figure 5 is a detail of the clutch throw-out dog;

Figure 6 is a sectional view of the clutch and 82 is shown as clamped between a pair of nuts receive in slidable relation thereto a supporting block 54 which may be adjusted by means of

screws

56 and 56. The

blocks

48 and 54 pivotally support the main framework of the machine.

The framework of the machine includes .a casting noted generally by the reference numeral 68, this casting having a base portion 62 and side portions 64 and 66. 'The side portion 64 of the casting is pivotally supported on a pin 68 secured in the supporting block 48. The side portion 66 of the casting is similarly mounted in pivotal relationship upon a pin 12 carried by the supporting block 54. I

Four heavy rods 14 are shown as being attached to the base'portion 62 of the casting 68 by means of nuts 16. Each rod 14 has a shoulder 18 which clamps a washer 88 against the base portion 62. The rods 14 are arranged in rectangular relationship and have secured to their other end a stationary head or platen 82. The head 84 and 86 threadedly engaging each of the rods 14. The nuts 84 are preferably calibrated as indicated, to facilitate accurate adjustment ofthe head 82. By means of this adjustment the machine can be made to accommodate different sizes of dies.

The platen 82 has a pair of ears 88, to each of which is pivotally connected a rack bar 98, whereby the platen 82 may be raised or lowered to adjust the inclination of the machine about its pivotal supports in the

blocks

48 and 54. 'Each rack bar 98 slides in a housing 9I and is engaged by a pinion 92 carried on a shaft 94 having a worm-wheel 96 rotated by a ,worm 98 carried by a second shaft I88 having a square end I82 projecting from the housing so that it can be engaged and rotated by a suitable tool. Each hous- 4 ing 9| ,is pivotally supported on a bracket I84 attached to a rail 34.

The platen 82 is provided with suitable T- shaped grooves for receiving the heads of clamping bolts I86 passing through clamp members I88 which secure the stationary part II8 of a die 45 to the platen 82.

The machine also has a movable head or platen I I2 which slides on the rods 14. This movable head is also provided with suitable T-shaped slots for receiving the heads of bolts II4 which secure a spacing member II6 thereto. A die box 8, which includes the movable portion I28 of the die, is attached to the spacing member II6 as by means of clamps I22. In Figure 1 of the drawings the movable platen H2 is shown as being in its forward position, in which position the two parts of the die are firmly held against each other and the machine is closed. In Figure 12 of the drawings the movable head H2 is shown as being in its'retracted or open position, and

to permit removal of the casting. The means for reciprocating the movable platen I I2 will now be described. v V

Referring particularly to Figures 2 and 3, I have shown a bracket I24 attached to the side portion 66 of the casting 68. This bracket I24 supportsan electric motor I26 which drives a small pulley I28 connected to a large pulley I38 by three belts I32. As shown most clearly in Figure 6, the pulley I38 is press-fitted on a hub I34 which is rotatably mounted ona shaft I36 ioumalled in the pin 12 and extending through the supporting block 54. The hub I34 is conthe two parts of the die are shown as separated fined between a shoulder I 38 formed on the shaft I36 and a plate I48 secured to the shaft by bolt inthe-casting 12 by opposed shoulders I56 and I58 which abut bushings I68 and I 62, respectively, which may be press-fitted or otherwise se-' cured in the casting 12. A further bushing I64 carries the extreme inner end of the shaft I36. It will be understood that the bushings I68, I62 and I64 may be of any suitable bearing material.

.The shaft I36 drives a pinion I66 which engages a largegear I68 keyed to a shaft I18 mounted in suitable bushings carried ln the side portions 64 and 66 of the casting 68. The shaft I18 is. removably secured in place by bearing caps I12. This shaft I18 is of such length that it does not extend outwardly beyond the side portions 64 and 66, thereby permitting swiveling of these side portions about their pivotal mountings in the bearing blocks 48 and 54.

The shaft I18 carries a main cam I14 shown most clearly in Figure 4. I This cam is of the uniform diameter type and may be either solid or have openings therein to reduce its weight. The cam follower associated with the cam I14 'com-' prises a casting II6 carrying a roller I18 which engages with the cam- I14. Screwed into the casting I16 are four rods I88 which are locked in place by nuts I82. The other ends of these rods are secured to a cap I84 by nuts I86 and I88. The cap I 84 carries a second cam roller I98 which engages the cam I14 at a pointdiametrically-opposite from the roller I18. Mounted on the shaft I18 adjacent each side of the cam I14 is a guide pulley I92 for engaging and guiding two of the rods I88 whereby the cam follower is always accurately located with respect to its cam I 14.

The movable head or platen H2 is advanced and retracted by toggle mechanism which I shall now describe with particular reference to Figures 1, 2 and 15 of the drawings. Pivotally attached to the upper part of the platen H2 and I96 whose other ends are pivotally connected to a cross-shaft I98. Also connected to the cross-v shaft I88 are the forward ends of a second pair of links 288 whose rearward ends are pivotally connected by a shaft 282' to ears formed on the base portion 62.

' The second set of lower toggle links 284 have their forward ends pivotally connected to platen II2 by a shaft 286 and their rear ends pivotally connected by a shaft 288 to the forward ends of a second pair of links 2) whose rearward ends are pivoted to ears formed on'the base portion 62 by a shaft 2I2. The central shafts I98 and 288 of the two sets of toggle links are connected by an inclined link 2I4, the lower end of the link 2I4 being notched out to receive the upper end of the casting I16 ofthe cam follower through which the shaft 288 passes.

As the cam I14 rotates and moves the cam follower to the position shown in Figures 1 to 4 of the drawings, the platen H2 is advanced to close the two parts of the die. When the two parts of the die are firmly clamped together, the links I96 and 288 of the upper set of toggles and the links .284 and 2I8 of the lower set of toggles are in aligned position, so that all of the force exerted upon the movable platen II2 by the inieetion of the metal is transmitted directly to the base portion'62 of the casting 68 and does not react upon the cam I14 and its associated mechanism.

When it is desired to remove the casting from the die the toggles are positively broken by the cam I14 which positively moves the platen II2 to retracted position. It will be noted that as the cam follower is reciprocated by the cam I14, this follower oscillates slightly about the cam shaft I18, and that during this oscillation it is guided by the engagement of the rods I88 with the grooved pulleys I82.

The clutch for connecting the drive-shaft I36 with pulley I38 may be either-manually or automatically controlled. I provide a handle 2I6 attached to a cross-shaft 2I8 mounted at one end in a bracket 228 attached to the side portion 64 of the casting 68 and mounted at its other end in a bracket 224 attached to arm 226 of casting 12. A beveled pinion 2281s pinned to the shaft 2l8 and engages a second beveled pinion 238 on a clutch control shaft 232 carried in the yokeshaped arm 226 of the casting 12. The shaft 232 carries a collar 234 secured thereto by bolts 236, this collar having a notch 238 best shown in Figure 8.

when the clutch is in driving relation the notch 238 is engaged by a spring-pressed detent 248 which holds the clutch in driving position. The detent 248 is located in a boss 242 on yokeshaped arm 226. Tlie spring tension of the detent memher is adjusted by screw 244.

The reduced portion of the clutch collar I48 is engaged by a pair of rollers 246 mounted'on bolts 248 carried by the two strips 258 and 252 of a clutch control arm indicated generally by the reference numeral 254. The two strips 258 and 252 are secured together by suitable bolts 256 and function as a single member. I

One end of the clutch control arm 254 is keyed or pinned to the shaft 232 to rotate therewith. The arm 254 and clutch member associated there with are urged to brake engaging position by a pair of springs 258 which connect bolts 248 with pins 268 secured to casting 12. The springs 258 are not strong enough to rotate the clutch arm 254 and shaft 232 against the resistance of the ,detent 248 and, in order to release the movable clutch collar I48 from engagement with the driving collar I44, it is necessary to exert some additional force on the detent 248. This additional force can be supplied either by manual actuation of the handle 2 I6 or by automatic means presently to be described. As soon as this additional force is applied and breaks the grip of the detent 248, the springs 258 pull the clutch collar I48 over into engagement with the brake I54 whereclutch collar;

upon the machine is stopped and locked in stopped position by the engagement of the teeth of the brake I54 with the cooperating teeth on the tal strips'26'4 may be bolted thereto in differentgages the nose 268 of a lever 218 which is pivoted at 212 to an arm 214 of the casting 12. The other end of the lever 218 is connected to one end of the clutch control arm 254 by a link 218.

It is to be noted that the stops 262 need give the slide 266 only a slight movement in order to break the grip of the detent 248, and that thereafter the springs 258 complete the disengagement of the movable clutch element with the driving pulley and shift this'movable clutch element to engage the brake. As soon as the movable clutch element engages the brake, the machine is brought to a stop. If the machine stopped with one of the stops 262 engaging the slide 266, it wguld be impossible to restartthe machine since the clutch could not be reengaged with the driving pulley. I therefore provide novel means to prevent this from happening.

Referring particularly to Figure 5, it will be seen that each stop, 262 is secured to a shaft 218 pivoted in bushings 288 located in the arcuate segments 264. A spring 282' biases the stop 262 in the direction of rotation of the gear I68 so that the forward shoulder 284 of the stop engages the segment 264. When a stop first engages the end of slide- 266, the stop is rotated about its pivot, against the tension of the spring 282 until the other shoulder 286 engages the segment 264. Thereafter further movement of gear I68 and stop 262 reciprocates slide 266L As soon. as the thereby moving this slide to its extreme limit, the spring 282 pulls the stop 262 past the end of the slide 266 and returns the stop to the forward position. The stop 262 would then be in the same position shown in Figure 5 but above the end of the slide 266 which is thereafter free to return when the handle 2I6 is actuated to reengage the clutch with the driving pulley. It will be noted that the contacting ends of the stop 262 and slide 266 are tapered to facilitate the return of the stop by its spring 282. i

The particular embodiment shown in Figures 1 to 12, inclusive, is set up for making die castings of zinc and its alloys, and the die cast metal is injected into the die under 'high pressures. The stationary part II8 of the die is provided with the usual gate 288 through which the molten metal is injected into the die. The stationary head or platen 82 is illustrated as being provided with two openings 2% and 284, eitherof which may be placed in registry with the gate 288. In the particular instance shown, the stationary part of the die is so located on the platen 82 that the gate 288 registers with the upper opening 284.

The platen 82 is vertically adjusted by means of the rack bars 88 and attendant mechanism,-

and also adjusted longitudinally of the rod 14 by nuts 82 and 86 so that the gate 288 is firmly pressed against the nozzle 286. This nozzle comprises two parts 288 and 388 which have a ball and socket connection whereby the part 288 may seat itself accurately with respect to the gate 288. The usual ring 382 surrounds the inlet end of the gate 288 and this ring 382 may'be water cooled, if desired. Y

The furnace 36 maybe fired by gas, oil or any other fuel indicated as being supplied through a pipe 384. The particular structure of the furnace forms no part of my invention, and any -or discharge end of the cylinder 308 communicates with the nozzle 296 through a passage 3l2. In the form of the invention shown in Figure 1, bolts 3 extend between the furnace pot and the platen 82 to hold the gate 298 firmly clamped against the nozzle 296 to prevent leakage of metal therebetween.

I preferably provide means .to maintain the nozzle 296 at such temperature that the molten metal will not solidify therein. This means includes a cover 316 which extends into;the opening 294 in the platen 82 and generally surrounds the nozzle 296 in spaced relation thereto. A burner pipe 3l8 extends through an opening in the cover 3| 6 to a point adjacent the nozzle 296 and carries a suitable burner 328 on its inner end which, in the present instance, is indicated as a gas burner of conventional type. The products of combustion flow around the nozzle 296 and serve to maintain it at the desired temperature, these products of combustion eventually escaping between the left-hand end of the cover 3I6 and the cylinder casting. The cover 316 may be formed of two semi-cylindrical castings, and it is to be understood that these castings do not form a tight fit with the casting in which the pressed air controlled by a novel air valve 338 and control mechanism which I shallnow describe.

Figure 9 shows the air valve in the position it assumes when the plunger 324 is in the upper position shown in Figure 1 of the drawings. In this position the air from a low-pressure source,

which is preferably under approximately fifty pounds pressure to the square inch, flows 'to the air valve 330 through 'a low-pressure supply pipe 332 communicating with a duct 334 located in the casting 336 of the air valve. As shown in Figure 9, the duct 334 is in communication with a passage 338 formed in a piston 340 which, in the position shown, establishes communication between the duct 334 and the port 342 leading to pipe 344 connected to the lower end of the' cylinder 328. In the position of the parts shown, the lower side of the piston 326 is exposed to the pressure of the low-pressure air and is held in elevated position thereby.

A source of high-pressure 'air, which is maintained under approximately five hundred pounds pressure to the square inch, is connected to he air valve 330 through a supply pipe 346. In the position of the parts shown in Figure 9, this supply of high-pressure air is cut off by the poppet valve 348 which is held closed by its spring 358. A pipe 352 leads to the upper or highpressure end of the cylinder 328.

The valve mechanism is controlled by a stem 354 projecting from the casting 336. This stem is shown as contactingwith one arm of a bell crank lever 356 pivoted on cars 368 formed on the casting-336. The other end of the bell crank lever 356is pivoted to a pull rod 368 whose other end is pivoted to a second bell crank lever 362 pivoted on a suitable bracket attached to the side of the furnace 36. The other arm of the lever 362 is connected to a second pull rod 364 which extends to a point adjacent the base of the die casting machine.

The pull rod 384- may be either manually or automaticaliy operated to control the actuation of the valve. In the embodiment shown in Figure 1, the pull rod 364 is connected to one end of a lever 366 pivoted on a, boss 368 formed on thebearing cap I12. The lever 366 carries at its opposite end a cam roller 310 which engages cam 312 which is mounted on and'rotates with the main cam shaft I10.

When the enlargement 314 on the cam 31-2 engages roller 318, the piston 340 is moved inwardly, thereby cutting oif communication between the low-pressure air supply and the lower end of the cylinder 328. Further inward movement of the piston 340 causes longitudinal groove 316 to register with port 318, whereupon the lower end of the cylinder 328 exhaust-s through pipe 344,

longitudinal passages

338 and 316 which merge with and are connected by annular groove 388,

and thence to atmosphere through port 318.

Furtherinward movement 01 the piston 348 opens the valve 348. It will be noted that this valve 348 is moved from its seat through a spring 382 which is confined between the base offthe valve and thepiston 348. This spring 382 constitutes a lost motion connection which permits a predetermined movement of the piston 340 be,-

' fore the high-pressure valve 348 is opened. Furthermore, as soon as this high-pressure valve is once opened, it is pushed to wide-open position, permitting free flow of air into the top of the cylinder 328. This position of the valve mechanism is shown in Figure 10.

The area of the piston 326 is approximately five times that of the plunger 324, whereby an air pressure of five hundred pounds per square inch on the piston 326 will inject the metal into the die under a pressure of twenty-five hundred pounds to the square inch. This pressure is far greater than that heretofore generally used in making die castings, and I have found that this increased pressure produces more perfect castings.

The enlargement 314 on the air valve control cam 312 extends through only a short are so that the high pressure is maintained on the metal for only a brief period of time, and thereafter springs 35!! and 382 return the parts of the air valve mechanism to their original position. During the return movement of these parts, the high-pressure valve 348 first closes and thereafter port 384 in the piston 34!] registers with the low-pressure air inlet 334. When this occurs high-pressure air from the upper end of the cylinder 328 opens poppet valve 386 and flows into the source of low-pressure air, thus conserving an appreciable part of the energy present in the and the lower end of the cylinder 328 to raise the piston 326 and plunger 324 to the position shown in Figure l. The poppet valve 386 prevents the flow of low-pressure air into the upper end of the cylinder 326.

The injection of molten metal into the die has been completed and in the embodiment shown in Figures 1 to 12, inclusive, one of the stops 362 is so positioned as to stop the machine at this point to permit cooling of the casting before its removal from the machine. It will be appreciated by those skilled in the art that where the casting is of such a nature that no prolonged cooling period is required, the machine need not be stopped at this point and may operate in a continuous cycle. After a suitable period of time the machine is restarted by movement of the handle 3l6 which controls the clutch.

As shown most clearly in Figure 12 of the drawings, the machine is set up to make the casting indicated at 392. This casting has a horizontal core 394 and a vertical core 396. The vertical core 396 is slidable in a guide 398 attached to themovable part I20 of the die. Before the casting 392 can be removed from the die, the core 396 must be withdrawn from the casting. An important feature of my invention lies in the particular means for automatically withdrawing the core 396.

Referring particularly to Figures 11 and 12, it will be seen that I have bolted a bracket 400 to the upper edges of the casting 60. The bracket 400, has upstanding arms 402 and 404 carrying

cross-pins

406 and 408. A frame having spaced arms 2 and M4 is pivotally mounted on the pin 408, a roiler 4I6 being interposed between the pin and the frame M0 to carry the force exerted therebetween. On the forward ends of the arms M2 and M4 are the socket members 418 and. 420 of a ball and socket joint, the ball portion 422 being carried by a post 424 which is adjustably and removably attached to the core 396.

The arms M2 and M4 are provided with a I series of holes 426, in one of which is located a pin 428 formin'ga pivotal connection between the arms and a pair of links 430. One end of each of the links 430 is pivoted to a bracket 432 mounted on the T-shaped track 434 provided on the upper side of the movable head or platen H2. The bracket 432 is held in laterally-adjusted position by a bolt 436. The other ends of the links 430 are pivotally connected by a pin 438 to one end of-a link 440 whose other end is pivoted on the cross-pin 406.

The full lines in Figure 12 indicate the position of the parts when the platen H2 is in its rearward position. As the platen is moved forward the frame 4I0, with its arms M2 and 4, are swung downwardly into the dotted line position indicated in this' figure. As they swing downwardly the core 396 is moved into the die. As the movable platen H2 approaches the forward limit of its movement a pin 442 connecting the forward ends of the arms M2 and 4 engages in the inclined slot 444 of a bracket 446 mounted on the T-shaped track 448 carried by the upper edge of the stationary platen 82. The bracket 446 is held in any laterally-adjusted position by bolt 450,

During the injection of the metal into the die the slot 444 assists in holding the core 396 in place against the force exerted thereon by the injected metal. When the movable platen H2 starts .its rearward movement, the pin 442 is first drawn out of the inclined slot 444. The inclination of this slot causes'an outward movement of the core 396 and materially assists in breaking any bond which may have been formed between this core and the die casting. As the movable platen H2 continues its rearward movement, the various parts of this core pulling mechanism assume the position shown in full lines in Figure 12 and the core 396 is completely withdrawn from the casting 392.

The horizontal core 394 is secured to the movable part I20 of the die, as, for example, by bolts 452, so that this core is removed from the casting by ejecting the casting fromthe movable part I20 of the die. Thedies are so designed that when the two parts of thedie are separated the casting adheres to the movable part of the die and some means must be provided for ejecting the casting therefrom. This means is another feature of my invention.

The casting 392 is ejected from the part I20 of the die by pins 454 extending through suitable openings provided in this part of the die. Thepins are attached to a head 456 mounted on one end of a rod 458. The rod 458 is guided by the die box and has a T-shaped end which engages in a vertical T-shaped slot 460 formed in a coupling member 462. The coupling 462 is mounted on one end of a rack bar 464 slidably carried in a housing 466 vertically adjustable on a frame 468 secured to and movable with the platen i 82.

The rack bar is held against rotation by a stud 410 engaging in a longitudinal groove formed in the upper surface of the rack bar. The rack bar may be reciprocated by a pinion 412 mounted on a shaft having a squared end for engagement byv a hand crank. I prefer, however, to eject the casting automatically where the nature of the casting makes. this feasible. For this purpose I attach a frame 414 to the forward edges of the side portions of the casting "60 and on this frame 414 I adjustably mount a stop plate 416 adapted II2 moves backwardly to separate the two parts of the die, this screw 418 will engage the stop 416 and eject the casting from the movable part I20 of the die. It will, of course, be understood that the particular casting shown cannot be ejectedfrom the die until after the core 396 has been withdrawn therefrom, and the adjustment of the screw 418 must take into account this necessary timed relationship. In some instances I prefer to complete the ejection of the casting by hand. In such instances the screw 418 is mad-- justed that, as the platen II2 completes its rearward movement, the casting will only be partially ejected by the engagement of this screw with the stop 416 and thereafter the ejection of the casting can becompleted by manual rotation of the pinion 412.

In setting up the machine the parts of the die are clamped to the platens 82 and H2 and the platen 82 is then adjusted both vertically and longitudinally so as to bring the gate of the die against the nozzle of the metal injecting mechanism. The bolts 3I4 are then secured inplace to hold the gate. firmly clamped against this nozzle. While no water circulating means for cooling the two parts of the die has been shown, it will be understood that. the usual water attachments are provided to circulate water through. the parts of the die.

The core pulling mechanism is attached to the core 396 and properly adjusted so that'the automatic operation of the machine completely withdraws this core. The particular casting shown as being made by the machine as set up in Figures 1 to 12 of the drawings has only a single core to' be laterally. withdrawn, and I have accordingly shown only a single core puller attached to the top of the-machine. The stationary platen 82 has a pair of side tracks 480, and the movable platen 2 has a similar pair of side tracks 482, whereby additional core pullers may be attached to either or both sides of these platens whenever desirable. Thescrew 418 of the casting ejecting mechanism is also adjusted toproduce the de sired ejecting action.

When the metal in the pot 306 has been brought to the appropriate temperature, the burner 320 is lighted and the machine is ready to operate. The motor I26 is started and the clutch control handle 2l6 is moved to engage the clutch collar with the driving pulley I30, whereupon the cam shaft I10 commences to rotate and the cam, I14 moves the platen H2 to close. the two parts of the die. As the platen I 12 moves forwardly, the casting ejecting pins 454 are retracted until they lie flush with the forward face of the depression in the movable part I20 of the die. Also during the forward movement of the platen H2 the core puller is moved downwardly to move the core 396 into the die and the pin 442 on the forward end of the core puller is locked in the slot 444.

As soon as the die has been closed the air control cam 312 operates the air valve 330 to admit tions.

high pressure air to the upper side of the piston 326, thereby moving this piston and its associated plunger 324 downwardly and injecting metal into the die ur iderapproximately 2500 pounds pressure. As soon as the air control cam 312 has moved far enough to release the air valve 330, one of the stops 262 engages the clutch shifting rod 266 and disengages the clutch from the driving pulley. The clutch springs 258 draw the clutch collar over into engagement with the brake I54 which stops the machine and locks it in stopped position, but before the machine has been stopped the stop dog 262 has moved past the end of the rod 266, thereby permitting restarting of the machine by the clutch control lever 2l6. As soon as the air valve 330 has been released it returns to normal position, thereby admitting low pressure air to the cylinder 328 and returning the piston 326 and plunger 324 to their upper posi- This relieves the pressure on the metal in the cylinder 308 and the metal in the nozzle flows back into this cylinder.

After a brief wait to permit suflicient cooling of the casting, the operator again moves the clutch control lever 216 to reengage the clutch with the driving pulley, whereupon the cam I14 retracts the movable platen H2. The initial part of this retractile movement causes the pin 442 in the forward end of the core puller to move upwardly in the inclined slot 444 and break any bond which may have been formed between the core 396 and the casting. Continued movement oi the platen I I2 swings the core puller to the full line position shown in Figure 12, thereby completelywithdrawing the core 396 from the casting.

After the core 396 has been withdrawn from the casting, the screw 418 on the casting ejecting casting is ejected therefrom and falls either into" a suitable receptacle located therebeneathor into.

the hands of the operator. As soon as the platen H2 has reached the limit of its rearward'move ment, the other stop 262 disengages the clutch from the driving pulley and again stops the ma chine, thus completing the cycle of operation.

In this position of the machine the exposed sur faces of the dies may be cleaned by the operator before the next casting is made.

Where the machine is being used to make light castings .which require no appreciable time to cool, and where it is not necessary to clean the surfaces of the die between successive castings. the stops 262 may be eliminated and the machine may be operated continuously to make any desired number of castings without stopping. On the other hand, where the nature of the casting so requires, additional stops may be provided to further break up the automatic periods of operation of the machine.

In Figure 13 I have shown a modified type of high-pressure injecting mechanism. In this form of injecting mechanism there is bolted to the top of the furnace 36 a casting 484 having a hollow cylindrical portion 486 constituting a hollow piston. To the upper end of this hallow piston 486 is threaded a nozzle 488 comprising a single element having a rounded nose which contacts with the gate 290 of the die. The nozzle has an external shoulder 490 which is engaged by a plate 492 bolted or otherwise secured to the platen 82 whereby the end of the nozzle is maintained firmly clamped against the gate 290. The nozzle490 may be surrounded by a cover 494 provided with an opening 496 through which a suitable burner pipe may be inserted to maintain the nozzle at a high temperature as described more fully in connection with the previous embodiment of my invention.

The structures of the hollow piston 486 and cylinder 498 are particularly advantageous 'where it is desired to make these partsof especially hard material, such as Nitraloy, which I have found to be a desirable material for making these parts as well as for making nozzles, sleeves, rollers and bearing parts. 7

Located in the bottom of the pot 306 is a reciprocable cylinder 498 having a port 500 which is normally open. The cylinder is carried by rods 502 secured to a head 504 pivotally attached to the lower end of the piston rod 506 connected to the piston 326 in the cylinder 328. The air. valve 330 for controlling the admission and exhaust of air to the opposite ends of the cylinder 328 is identical with the air valve described in connection with the previous embodiment. In this modification, however, the high pressure air is admitted to the lower end of the cylinder 328 and the low pressure air-is admitted to the upper end of this cylinder. In this .modification the piston 326 is normally located in the lower end of the cylinder.

cylinder 328 and the cylinder 488 may be selected to give the desired pressure on the metal injected into the die. I have found that where a 500 pounds air pressure is used in the cylinder 328 excellent results are obtained where the area of the cylinder 498 is one-fifth of that of the-cylinder 328, although it will be understood that other pressures and ratios of area may be used when desired.

In Figures 14' and 15 I have shown my die. casting machine arranged in vertical position and utilized in connection with metal injecting mechanism of the gooseneck type. In these figures I have shown the casting 50 pivoted about its sup- 15 port on the

blocks

48 and 54 so that the base portion of the casting 60 rests upon the floor of the shop. The stationary platen 82, movable platen II2, and. their cooperating mechanism, are the same as that previously described. In this form of my invention the rails 34 of the previous embodiment have been dispensed with, and the furnace 38 is mounted directly upon the guides 46 carried on the upper ends of the

uprights

20 and 22. v

A frame 588 is bolted to the upper ends of the rods 14, the other end of this frame being supported on a post 5I0 resting upon the furnace 38..

The frame 588 has upstanding sides 5| 2 and 5I4, each of which contains a cam slot 513 forming guides for a transverse rod 5I8, to the ends of which are attached arms 528. The lower end of each arm 520 has an opening 522 in which a collar 524 is adjustably secured by a screw 525. Each collar 524 pivots upon a pin 528 attached to one side of the movable platen H2 The arms 520 have lateral extensions 530 carrying a transverse pin 532 to which is pivoted the ear 534 of a gooseneck 535.- This gooseneck includes a second ear 538'pivoted to a pin 540 sup- 40 ported bya pair of adjustable links 542 pivoted on -a rod 544 mounted in the frame 508. A second pair of adjustable links 548 connect the pins 540 and 532 and relieve the gooseneck 536 of any strain.

5 The gooseneck 536 is supplied with air under ""high pressure through a swivelly jointed pipe 548 leading from the valve 330 which is identical with the valve shown in Figures 9 and 10. In this embodiment the high-pressure air under approximately 500 pounds pressure to the square inch,

is supplied through the .pipe 346, and its admission to the gooseneck through the jointed pipe 548 is controlled in the manner previously described,

through the actuation of the valve control rod 550. In this embodiment of my invention there is no need for a low pressure air supply. How'- ever, I prefer to connect the valve 338 with a container of low pressure air by means of a pipe- 332, as in the previous embodiment of my invention, so that some of the air exhausted from the' gooseneck536 may be conserved and utilized for other purposes about the shop. The valve outlet which in Figures 9 and 10 is shown as being connected with a pipe 344, is plugged up when the valve is used in connection with the embodiment shown in Figures 14 and 15 of the drawings.

A feature of thisform of my invention lies in e the means provided to prevent accidental operation ofthe air valve when the machine is in open position. To this end I attach the lower end of the valve control rod 550 to one end of a lever 552 pivoted at 554 on a pin carried by a bracket 556 carried by the cap I84 of the main cam follower. The other end of the lever 552 is provided with a removable cam follower roller control cam 312.

overlies the link 550 whereby the air valve may 558 which engages the air controlled cam 312. The forward end of the lever 552 is also-adapted to be engaged and moved to valve actuating position by a link 580 controlled by a handle 552, whereby the admission of air to the gooseneck 535 may be manually controlled. When manual control of the air is to be used, the automatic control'is eliminated by removing the cam follower roller 558.

When the machine is in the closed position shown in Figures 14 and 15 of the drawings, the roller 558 is in position to be engaged by the air Also the end of the lever 552 be manually controlled by the handle 562. However, when the machine isin open position, the end of the lever 552 carrying the roller 558 is moved away from the control cam 312 and'also 'from the link 5150, as indicated by dotted lines in Figure 14, whereby the air valve cannot be opened either by the cam or by the handle when the machine is-in open position. This safety feature prevents accidentaloperation of the air valve by the machine operator when the two parts of the die are separated. It also prevents untimely operation of the air valve by an air control cam which may have slipped on its shaft or which may have been incorrectly timed when the machine was assembled.

In Figures 14 and 15 the clutch control handle 2H5 is attached to a control shaft 563 which is pivoted in a bracket 564 carried by a bar 565 bolted to the side portions of the casting 50. Also attached to this bar is one end of a heavy spring 568 whose other end is attached to an angle iron 510 secured to the link 2 I4 of the toggle mechanism, whereby the roller I is pressed against the main c'am I14. This spring 568 same as the operation of the embodiment shownin Figures 1 to 12, inclusive. When the movable platenJIZ is moved downwardly, the gooseneck 536 is moved to the left, as viewed in Figure 14,

and'drops down into the pot 512 containing the molten metal which maybe either aluminum orzinc. As the gooseneck 536 reaches the lower end of its movement, a fresh supply of metal enters thegooseneck through its nozzle 514. Upon the following upward stroke of the platen I I2 the gooseneck is raised to the position shown in Figures 14 and 15, in which position the-nozzle 514 is firmly held against the gate in the die.

The air valve 330 is then tripped to admit high pressure air directly upon the top of the metal in the gooseneck 535, whereupon this metal is forced into :the die. The pressure is then relieved, completing the cycle of operation.

In Figure 16 of the drawings I have shown my machine arranged with the movable frame in a substantially horizontal position. In this figure I also use a movable gooseneck for feeding the metal into the die. The machine, as. arranged in this figure, is particularly adapted for the making of die castings of aluminum and its alloys.

In the form shown in Figure 16, the stationary platen 82 is carried by a pair of supports 516- the lower surface of the die. The gooseneck 582 is bolted to a frame 586 pivoted on a post 588 attached to a bracket, 590 secured to the rear of the furnace 36.

The actuating mechanism for raising and lowering the gooseneck 582 comprises a cam 592 mounted on the main cam shaft I10 adjacent the air control cam 312. The cam 592 is of the uniform diameter type and is contacted by opposed rollers 594 and 596 carried by cam follower 598 pivoted at'600 on the casting 60.. The cam follower 598 is connected to one end of an adjustable link 602 whose other end is connected to an arm 604 keyed to a shaft 606 extending through the furnace supporting rails 580. v

A second arm 608 i'skeyed or otherwise nonrotatably attached to each end of the shaft 606,

machine in case a drop of solidified metal or other obstruction becomes interposed between the nozzle 584 of the gooseneck and the gate of the die.

In order to relieve wear on the cam shaft I10 and .its supporting bearings, I preferably provide means for balancing the weight of the gooseneck 582. In Figure 16 this balanced means is shown as a tension spring 624 connecting the arm 604 with the cross-pin 518.

The air is admitted into the upper end of the gooseneck 582 through a swi-veled pipe 626 which connects with a source of high pressure air supply through an air valve which may be of any desired type but which is preferably the air valve shown in detail in Figures 9 and 10 of the drawings. This air valve is controlled through the rod 628 connected to one end of a bell crank lever 630 pivoted on a side rail 580 and actuated through a pull rod 632 connected .to one end of a lever 634 4 pivoted on the upright 20 and having its other end engaging the air control cam 372.

I have found that aluminum is particularly apt I to splash into the air supply pipe of the gooseneck and that such splashing will in time eventually seal the air supply line to the gooseneck. In

order to avoid this I provide the structure shown in Figure 17 of the drawings; The air supply line 626 is' attached to a fitting 636 threaded into the upper end of the gooseneck 582. The lower end of the fitting 636 is of reduced diameter and is provided with diagonal passages 638 which connect the pipe 626 with the passage 640 formed in the upper end of the gooseneck.

This passage640 is provided with an internal rib or shoulder 642 located a short distance below the lower end of the fitting 636, and this rib prevents the molten metal from splashing up-into the space between the reduced lower end of the fitting,

- 636 and the adjacent wall of the passage 640. The

downwardly directed lower end of the fitting 636 is hemispherically concave, asindicated at 644, to direct away fromthe diagonal passages 638 any metal which may splash up against this surface. This particular arrangement-of baflies for preventing clogging of the air inlet pipe, due to splashing of the molten metal, has proved to be exceedingly effective in use.

The mode of operation of the embodiment shown in' Figure 16 is essentially the same as the mode of operation of the embodiment shown in Figures 14 and 15. It will therefore be unnecessary to describe in detail the operation'of the mechanism shown in Figure 16.

An important feature of my die casting machine lies in its adaptability for making various types of castings using different metals having different melting points and injected under different pressures. The design of my machine is such that any of the desired adjustments may be made without disturbing the fundamental relationships of the mechanism. Furthermore, the

machine may be operated continuously or any desired combination of automatic operation and hand control can be obtained by the utilization of a few simple stops which can be easily attached and detached or rearranged at will.

While I have shown several arrangements of my invention, it is to be understood that my invention is not limited to the specific arrangements shown and, furthermore, that my invention is not limited to the specific details of construction shown in the drawings and described in the specification. My invention may assume various forms and the scope of my invention is to be limited solely by the following claims.

I claim:

1. In a die casting machine of the class described, the combination of a frame, a stationary platen provided thereby, a second platen mov- I ably mounted on said frame, said platens adapted for attachment of die parts thereto, means for reciprocating said movable platen, and a core puller mounted on said frame, said core puller including a core-carrying member pivoted on said frame, a link pivotally connected to said'member and said movable platen whereby movement of said platen causes said core puller to insert and withdraw a core.

2. In a die casting machine of the class described, the combination of a frame providing a stationary platen, a second platen movable on said frame, means for reciprocating said lastnamed platen, said platens adapted to have die parts attached thereto, a core puller mounted on said frame, said core puller including a member pivoted on said frame, a link pivotally-connected to said member and said movable platen for moving said member, and means associated with said stationary platen for rigidly clamping said core puller to resist the force exerted when metal is injected into a die attached to said platens.

3. In a die casting machine of the class described, the combination of a frame, a. movable platen carried thereby, means for reciprocating said platen including a source of power, a cam shaft, a jaw clutch for connecting said shaft with and disconnecting it from said source of power, a stop rotatable with said shaft for initiating disengagement of said clutch, and spring means for completing the disengaging movement of said clutch.

4. In a die casting machine, the combination of a frame, a movable platen mounted thereon, a cam for reciprocating said platen, a cam follower for said cam, said cam follo'wer being connected to said platen, said cam follower including spaced rods, a cam shaft passing between said rods, and a guide pulley carried by said shaft and having flanges engaging said rods to prevent axial displacement of said cam follower.

5. In a die casting machine, the combination of a pair of relatively movable platens, means for reciprocating one of saidplatens including a cam, a cam shaft, and a cam follower, said platens being adapted for the attachment of a die thereto, air operated means for injecting metal into said die, an air valve for controlling said means, a second cam on said shaft for-operating said air valve, and an air valve cam follower mounted on said first-mentioned cam follower so that said air valve cam follower is out of contact with its cam when the dies are open.

6. In a die casting machine having a pair of platens adapted to have a die secured thereto and air operated means for injecting metal into said die, the combination of an air valve controlling said means comprising a first port connected with a source of high pressure air, a second .port through which high pressure air is supplied to said metal injecting means, a third port connected to a vessel containing low pressure air, a valve controlling said first-mentioned port, means for'opening said valve, a piston including a second valve for cutting off communication between said first and third ports while said valve is open, said second valve permitting flow of air from said second port into said third port, and means for operating said valve.

'7. In a die casting machine including a pair of platens adapted to have a ,die secured thereto, and metal injecting means comprising a cylinder adapted to be filled with metal a plunger for forcing the metal from the cylinder into the die, a second cylinder, an air operated piston in said second cylinder, and means connecting said two pistons, the combination of an air valve, pipes connecting said air valve with sources of high and of said cylinder, means provided by said piston for simultaneously venting the other end of said cylinder, means for establishing communication between said end of the cylinder and-the source air cylinder having a cross-section approximately five times that of said first-mentioned cylinder, a

Y piston in said air cylinder, and a rod connecting said piston and plunger, the combination of an air valveconnected to a source of low pressure air and also connected to a source of high pressure air, a connection from said air valve to each end of said cylinder, means normally closing communication between said source of high pressure air and said air valve, means normally maintaining communication between said source of low pressure air and one end of said cylinder, a piston movable in said cylinder to cut off said last-mentioned communication and to open communication between said source of high pressure air and the other end of said cylinder, means for venting the first-mentioned end of said air cylinder during the admission of high pressure air to the other end thereof, said valve piston movable upon its return stroke to permit cutting off of the supply of high pressure air to said valve and to vent a part of the high pressure air supplied to said air cylinder into said source of low pressure air, and means for reciprocating said air valve piston.

9. In a die casting machine including a pair of platens adapted to have a die attached thereto, means for feeding metal to said die comprising a cylinder adapted to be filled with molten metal and a plunger for expelling the metal therefrom, and means for reciprocating said plunger including an air cylinder having a piston therein connected to said plunger, the combination of air valve means including a body having a chamber therein, a first port connecting said chamber with a source of high pressure air, a valve for closing said port, a second port leading to one end of said cylinder, a third port leading to the opposite end of said cylinder, a fourth port leading to a source of low pressure air and a fifth port leading to atmosphere, a piston reciprocable in said chamber, said piston having a passage normally maintaining said third and fourth ports in open communication, said piston being movable first to cut off communication between said third and fourth ports and thereafter to open said valve to admit high pressure air to said chamber and simultaneously to connect said third and fifth ports, said piston forming a barrier across said chamber between said second and third ports, and a one-way valve carried by said piston for permitting discharge of air through said second port into said fourth port and thence to the source of low pressure air.

10. In a die casting machine, the combination of a stationary platen, a movable platen, said platens being adapted to have a die attached thereto, a cam shaft, a cam thereon, a cam follower for said cam connected to said movable platen, driving means for said cam shaft including a clutch and means for shifting said clutch including a pivoted stop rotatable with said cam shaft, said stop having a pair of opposed inclined surfaces for engaging a cooperating element, a spring for rotating said stop about its pivot in the direction of rotation of said cam shaft, and shoulders limiting rotation of said stop under the influence of said spring and also under the influence of a cooperative element engaged thereby.

11, In a die casting machine, the combination of a base including a pair of uprights, an adjustable block slidably supported by each upright, a

frame pivotally mounted on said blocks, said pivotal, mounting including a casting in which a driving shaft is journalled, a driven shaft carried by said frame, gears connectingfsaid driving and driven shafts, a pair of platens on said frame, a cam on said driven shaft for reciprocating one of said platens, a motor on said frame, a' clutch for connecting said motor with said driving shaft, a clutch control rod slidably mounted in said casting, a plate adjustably attached to one of said gears, a stop member pivoted on said plate, said stop member having a pair of tapered ends for for supplying metal under pressure to said nozzle and die, and means for maintaining said nozzle hot including a removable cover, a burner located between said cover and said nozzle, and means extending through said cover for supplying fuel I to said burner, said cover causing the products of combustion from said burner to flow along said nozzle in a generally horizontal direction but permitting said products to escape adjacent a furnace containing said supply means, said cover providing a return for any metal escaping from said nozzle.

13. In a die casting machine of the class described, the combination of a frame including a 14. In a die casting machine having die carry-- ing means, a gooseneck for supplying metal to said die, and a pipe through which air is supplied to said gooseneck, a fitting interposed between said pipe and said gooseneck, said fitting. including a reduced lower end adapted to extend in spaced relation into a straight bore in said gooseneck, said reduced lower end having diagonal passages establishing communication between the interior of said gooseneck and said pipe, and an annular internal rib in said bore protecting said diagonal passages against splashing metal.

15. A die casting machine of the class described, comprising a base, a frame pivoted thereon, said frame including a stationary platen, a movable platen slidable on said frame, said platens adapted to have secured thereto the parts of a 'die, a cam shaft carried by said movable frame, a cam on said shaft for reciprocating said movable platen, drivingmeans for said cam shaft extending through the pivotal mounting of said frame, and means for shifting said frame about its pivotal mounting.

16, A die casting machine of the class described, comprising a base, a frame pivoted thereon, said frame including a stationary platen, a movable platen slidable on said frame, said platens adapted to have secured thereto parts of a die, operating means for said movable platen carried by said pivoted frame, driving means for said operating means extending through the pivotal mounting of said frame, and means for shifting said frame about its pivotal mounting.

17. In a die casting machine of the class described, the combination of .a frame, a stationary platen provided thereby, a second platen movably mounted on said frame, said platens adapted for attachment of die parts thereto, means for reciprocating said movable platen, and a core puller mounted on said frame, said now puller including a pair of spaced rods pivoted at one end to said frame, core carrying means universally connect- ,ed to the other end of said rods, and an adjustable link connecting said rods with said movable platen whereby movement of said platen core.

ends thereof, said source of power including a;

rotating member having teeth for engagement with the teeth of said clutch, a stop rotatable with said shaft for initiating disengagement of said clutch, a brake having teeth adapted to be engaged by said clutch, and resilient means for completing disengagement of said clutch from said source of power .and moving said clutch into engagement with said brake. 1

19. In a die casting machine, the combination of a frame, a pair of platens adapted to have a die attached thereto, means for moving one of said platens, a core puller comprising a rod pivoted at one end on said frame, a pair of pivoted links having one end pivoted to said frame and the other end pivoted to said movable platen, a

pivotal connection between said links and said rod, and means for attaching a core to the free end of said rod. I

20. A die casting machine of the class described,

comprising a base, a frame pivoted thereon, a I

pivotal mounting for said frame, permitting move- -ment of said frame through an arc of greater than degrees, said frame including a casting having a portion adapted to rest upon the floor when said frame is in a pre-determined position, and sides extending from said portion and connected to said pivotal mounting, said frame also including four rods attached to said casting and a stationary platen, a movable platen slidable on said rods, said platens adapted to have secured thereto the parts of a die, a cam shaft mounted in said sides,-a cam on said shaft for reciprocating said movable platen, and driving means for said cam shaft, including a driving shaft supported by said base and passing through said pivotal mounting.

21. In a die casting machine of the class described,'the combination of a frame providing a fixed platen, a movable platen mounted on said cam engaginga pair of said rods to guide said' g cam follower in its oscillatory movement and prevent axial displacement of said follower from said cam.

22. A die casting machine comprising-a pair of platens adapted to have a die secured thereto, said die including a gate, metal feeding means including a nozzle means for clamping said nozzle against said gate, means for supplying metal under pressure to said nozzle and die, and a twopart cover enclosing said nozzle, a heating element located between said nozzle and' said cover, and means including said cover providing a passage for return to said supply means of metal escaping from said nozzle.

nor F. Jormsou. a