US3556403A

US3556403A - Wax supplying apparatus for pattern molds

Info

Publication number: US3556403A
Application number: US768430A
Authority: US
Inventors: Ralph Manginelli
Original assignee: Individual
Current assignee: Individual
Priority date: 1968-10-17
Filing date: 1968-10-17
Publication date: 1971-01-19
Anticipated expiration: 1988-01-19

Abstract

Molten wax in a supply tank is pumped into a heated manifold having a plurality of valve-controlled nozzles through which to force wax under pressure into clamp-on molds to form wax patterns therein, with the tank being supplied with hard wax at a rate, and the wax being heated and agitated in the tank, to have at all times an available supply of molten wax adequate for continuous or interrupted production of wax patterns.

Description

United States Patent lnventor Ralph Manginelli 6 Clover St., West Haven, Conn. 06516 768,430

Oct. 17, 1968 Jan. 19, 1971 Appl. No. Filed Patented WAX SUPPLYING APPARATUS FOR PATTERN MOLDS 13 Claims, 7 Drawing Figs.

US. Cl 239/135, 239/139 Int. Cl B05b 1/24 Field of Search 239/135, 139

[56] References Cited UNITED STATES PATENTS 1,587,736 6/1926 Schenck 239/139 2,817,600 12/1957 Yahnke 239/139X 2,872,245 2/1959 Groth 239/139X Primary Examiner-Lloyd L. King Att0mey--Walter Spruegel ABSTRACT: Molten wax in a supply tank is pumped into a heated manifold having a plurality of valve-controlled nozzles through which to force wax under pressure into clamp-on molds to form wax patterns therein, with the tank being supplied with hard wax at a rate, and the wax being heated and agitated in the tank, to have at all times an available supply of molten wax adequate for continuous or interrupted production of wax patterns.

PATENTED JAN] 91am SHEET 2 BF 2 INVENTOR 1 WAX SUPPLYING APPARATUS FOR PATTERN MOLDS This invention relates to the making of wax patterns for investment casting in general, and to apparatus for making wax patterns in particular.

Prior apparatus of this type have a supply of molten wax from which to charge molds. However, while these prior apparatus are satisfactory in some respects, they are deficient in other respects. Thus, to mention but a few of the more serious deficiencies of these prior apparatus, they have cylinders which hold molten wax from which molds are charged until the wax supply is exhausted, whereupon the empty cylinders are replaced with full cylinders. Moreover, each of these prior apparatus is equipped for charging two molds at the most. Accordingly, the pattern production rate of each apparatus is exceedingly low, considering not only the production of a maximum of two patterns at a time, but also interruptions of a going operation necessitated by periodic replacement of an empty cylinder with a full cylinder, yet the cost of these apparatus is quite high.

It is among the objects of the present invention to provide apparatus of this type which has none of the aforementioned and also other deficiencies of the prior apparatus, and which lends itself to continuous and uninterrupted production of wax patterns for any desired length of time, with the production rate of wax patterns being, moreover, much greater than that of the prior apparatus.

It is another object of the present invention to provide apparatus of this type with a tank holding a supply of molten wax which, through suitable heated conduit means and under pump action, extends to, and is under injection pressure at, a multiplicity of valve-controlled nozzles through which to charge a like number of molds, with the tank having provisions for melting the wax therein and keeping it in molten condition, and the wax in the tank being augmented so that the molten wax supply therein is adequate for continuous production of wax patterns at any rate, including the maximum rate attainable on quickest possible replacement of charged molds with empty molds at the injection nozzles. With this arrangement, the supply of molten wax is inexhaustible for any type of pattem-molding operation involving all or fewer than the available injection nozzles, and a pattern-molding operation may be started instantaneously at any time after an interrupted operation.

It is a further object of the present invention to provide apparatus of this type in which the molten wax is throughout the aforementioned tank and conduit means kept within a narrow range of low temperatures at which the wax will not start to solidify and is at the injection nozzles of a plastic consistency at which it will undergo quickest solidification in a mold on injection thereinto. [n so doing, excessive heating of the wax and ensuing undesirable chemical changes in the wax, prolonged wax injection cycles, and high melting point of the wax patterns, are avoided.

Another object of the present invention is to provide apparatus of this type in which a pump for applying the aforementioned injection pressure to the wax at the injection nozzles is interposed between the wax supply tank and the conduit means to these nozzles, with the intake of the pump being in direct communication with the molten wax in the tank and its output being in communication with the conduit means, and the pump being throughout its wax passages heated to keep the wax therein within the aforementioned narrow range of low temperatures at which it will not congeal to impede the pump action in anyway. In thus heating the pump, the same will function at the low temperature of the molten wax in the tank, and thus obviate undesirable overheating of supply wax as was heretofore customary for proper functioning of a wax pump.

A further object of the present invention is to provide apparatus of this type in which the, conduit means from the output of the wax pump to the injection nozzles is not only of sufficient longitudinal extent to afford adequate spacing of any desired number of nozzles from each other for comfortable operating space at each nozzle, but is also of quite considerable volume to hold a correspondingly large amount of wax which is easy to keep at the desired uniform temperature with the least regulation of the heat applied to the conduit means.

it is another object of the present invention to provide apparatus of this type in which the wax tank, wax pump and conduit means to the injection nozzles are heated by surrounding oil which by pump action is constantly circulated in a path at a station of which the circulating oil is heated, with the arrangement being such that in its circulatory path the oil is heated, with the arrangement being such that in its circulatory path the oil is heated, and, hence, at maximum temperature where in heat-exchange relation with the region of the tank from which the wax pump draws, then passes successively into heatexchange relation with the injection nozzles, thence with the conduit means and finally with the pump to be then returned to the heating station in the path for recirculation. With this arrangement, oil of substantially maximum temperature keeps the wax safely above its melting point at those places where even slight congealing of the wax might spoil an operation, i.e., at the intake of, and in the wax pump and in the injection nozzles, while oil at all other places of its circuitous path remains sufficiently hot to keep the rest of the wax in plastic condition. Further, the preferred provision of a poweroperated wax agitator in the tank for quickest melting and distribution of periodically added hard wax in the wax supply, is additionally instrumental in keeping this entire wax supply in the tank in molten condition.

It is a further object of the present invention to provide apparatus of this type in which the conduit means is in the form of a preferably horizontal jacketed manifold having a longitu dinal wax passage closed at one end and being with its other end in communication with the output side of the wax pump, and the injection nozzles are provided on separate jacketed casings which are mounted and properly spaced on the manifold and have valve-controlled ports that lead from selectively located and easily bored lateral outlets from the wax passage in the manifold to the nozzles, with oil from the output side of the oil pump being delivered to the jackets of the nozzle casings and these jackets having overflow tubes through which the oil passes to the jacket of the manifold in the course of its circulation. This makes for structural simplicity of the manifold and nozzle casings and for their ready assembly according to any desired location and spacing pattern of the nozzle casings on the manifold, and the oil is advantageously enclosed in the jackets of the respective parts, yet the overflow of oil from the casing jackets to the manifold jacket leaves at all times oil in the casing jackets at a level adequate for proper heating of the injection nozzles.

Another object of the present invention is to'provide apparatus of this type in which the aforementioned wax passage in the manifold is a through-passage, and the manifold also has at both ends flanges or other mounting provisions which may be used for mounting a cover to close the far end of the wax passage in one or more installed manifolds.

A further object of the present invention is to provide apparatus of this type in which the wax tank is also jacketed and has an oil heating unit in its jacket, and there is provided on top of the tank a container into which oil from the manifold jacket discharges and from which it is returned to the tank jacket through an overflow pipe in the container so that the oil in the latter is at least at the minimum overflow level therein, and the wax pump is mounted in this container so as to be heated by the oil therein, with the wax pump extending with its intake end into the wax supply in the tank, and there being provided at this intake end aseal by which the oil in the container is sealed from the wax in the tank. Thus, by providing for overflow of the oil from the nozzle casing jackets to the' manifold jacket and from the container to the tank jacket, not only are minimum safe oil levels established for proper heating of the injection nozzles and wax pump for reliable per- It is another object of the present invention to provide apparatus of this type in which for wax leakage prevention beyond the output side of the wax pump the wax injection pressure established by the latter is kept relatively low, but provision is made for applying to the wax in a mold, immediately after its injection thereinto and closure of the injection valve, a booster pressure of much higher magnitude than the injection pressure until the wax in the mold is substantially solidified, to thereby greatly minimize shrinkage of the wax pattern in the mold in the course of its solidification therein. This is achieved by providing in each nozzle casing an opening branching from the wax port therein intermediate the associated injection valve and nozzle and serving as a cylinder for the reception of a single-acting plunger to which is applied the booster pressure for transmitting the same to the wax trapped in the port, nozzle and mold when the injection valve is closed.

Another object of the present invention is to provide apparatus of this type in which any mold may be charged with wax at the lower injection pressure and the wax charge therein then subjected to the higher booster pressure as aforementioned, or alternatively, any mold may be charged with wax at the booster pressure and the wax charge therein kept at this booster pressure throughout the solidification cycle. This is achieved by providing in the wax port in each nozzle casing between the control valve and nozzle a supplemental threeway valve, and making the aforementioned cylinder in the casing of sufficiently large volume to hold at least a full wax charge in the casing of sufficiently large volume to hold at least a full wax charge for the associated mold when the plunger is retracted, with the supplemental valve having three positions in which to provide communication between the control valve and both, the nozzle and cylinder, between the control valve and cylinder only, and between the cylinder and nozzle, respectively. With this arrangement, the supplemental valve may be manipulated into one position in which simultaneously to charge the associated mold and the cylinder with wax at injection pressure on opening the control valve, and to apply the higher booster pressure to the wax charge in the cylinder and in the mold after closing the control valve and applying the booster pressure to the plunger, or the supplemental valve may be manipulated into two successive positions in which to charge the cylinder only with wax at injection pressure on opening the control valve, and to charge the mold with wax from the cylinder at booster pressure on applying the latter to the plunger and on first closing the control valve, respectively. Thus, regardless of whether a mold is charged with wax at injection pressure or at a higher booster pressure, the booster pressure, whenever applied, is confined to passages within the nozzle casing and does not interfere with the lower injection pressure of the wax between the wax pump and nozzle casing. The supplemental valve has also this further advantage that it may be manipulated into, and left in, a fourth position in which to provide communication between the control valve and associated mold only for operations in which the latter is charged with wax at injection pressure and the wax charge is kept at this pressure throughout the solidification cycle. This additional mode of operation of the apparatus, i.e., without any booster pressure on the wax charge in a mold, is indicated for small wax patterns where shrinkage in the solidification cycle is negligible, or is indicated for wax patterns generally where shrinkage is of no consequence.

Further objects and advantages will appear to those skilled in the art from the following, considered in conjunction with the accompanying drawings.

ln the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

FIG. 1 is a side view of apparatus embodying the present invention;

FIG. 2 is a top view of the same apparatus;

FIG. 3 is an enlarged section through the apparatus taken substantially on the line 3-3 of FIG. 2;

FIG. 4 is an enlarged section through the apparatus taken substantially on the line 4-4 of FIG. 3;

FIG. 5 is a fragmentary section through apparatus embodying the present invention in a modified manner;

FIG. 6 is a fragmentary section similar to'FlG. 5, but showing prominent operating elements in different positions; and

F IG. 7 is a fragmentary section through apparatus embodying the present invention in a further modified manner.

Referring to the drawings, the reference numeral 10 designates a wax supplying apparatus or installation for pattern molds which has as its major components a wax supply system 12 and a wax distribution system 14 with a plurality of wax injection nozzles 16.

The wax supply system 12 comprises a tank 18 which holds a molten supply s of wax w, and a pump 20 for supplying the distribution system 14 with wax from the supply s. The tank 18 is open at the top through which to introduce hard wax into the tank from time to time to keep the wax supply therein at an adequate level in operation of the apparatus. Heat is applied to the wax supply s to keep the same in molten state, and the tank is to this end provided with a jacket 22 for holding a heating medium, preferably oil 0, with the jacket 22 being formed by an outer container 24 which is sealed throughout from the interior of the tank.

The pump 20, which is suitably mounted in a container 26 on top of the tank jacket 22, has a casing 28, an inlet tube 30, an outlet tube 32 and a passage in the casing 28 between these tubes, with this passage being indicated diagrammatically at 34 (FIG. 3). The pump 20 may be of well-known type having an air motor to operate a reciprocating plunger (neither shown) for pumping wax on each plunger stroke, with the pump delivering wax under a presettable constant pressure which is the injection pressure of the wax, and the motor being supplied with compressed operating air through a flexible hose 36. The pump 20 is provided with a jacket for constant circulation therethrough of heated oil to keep the wax in the pump in molten state. The pump jacket is in this instance the container 26 in which heated circulating oil 0 is kept at a level L above the wax passage 34 in and outlet tube 32 of the pump, with heated oil being constantly supplied to the container 26 in a manner described hereinafter, and the oil level L in this container being kept at the level of an overflow tube 38 therein which leads to the tank jacket 22. The inlet tube 30 of the pump 20 reaches into the molten wax supply in the tank 18 preferably near the bottom 40 of the latter which is next to an electric heating element 42 in the tank jacket 22 to heat the oil therein. in order to assure proper operation of the pump 20 at a preferred temperature of the molten wax supply s which is at or little above its melting point, it is essential that the inlet tube 30 of the pump is also heated. To this end, the inlet tube 30 is also provided with a jacket 44 through which heated oil is circulated, with this jacket being open to the container 26 and formed in this instance by a downward extension tube 46 in the bottom 48 of the container 26 through which the inlet tube 30 extends with lateral clearance so that the jacket 44 is in the form of a ring chamber which at the bottom is closed by a ring 50 in the extension tube 46 through which the inlet tube extends. This ring chamber 44 is further sealed from the wax w in the tank 18 by a sealing ring 52, preferably of teflon, which by a nut 54 is tightly clamped between the ring 50 and the inlet tube 30. The outlet tube 32 of the pump extends in sealed fashion through an aperture in the container wall 56 (FIG. 3).

Preferably assisting the heated oil in the tank jacket 22 in keeping the wax supply s in molten state is a power agitator 58 with a center hub 60 and paddles 62, of which the hub 60 is formed by spaced sections 64 and 66 tumable on bearings 68 and 70 on the extension tube 46 and spacer rods 72 between these sections 64 and 66, while the paddles 62 are formed by rods extending outwardly from the spacer rods 72 and other rods which connect the outward rods at their outer ends. The

power-driven chain for power operation of the agitator 58.

The wax distribution system 14 comprises in this instance a preferably horizontally disposed longitudinal manifold 82 having a longitudinal wax passage 84 which is open at one end 85 and closed at its other end by a cover 86 (FIGS. 1 and 2), and a plurality of casings 88 providing the injection nozzles 16 and being suitably mounted in spaced relation on the manifold 82 preferably on top thereof. The manifold 82 is with one end mounted at 90 on the wall 56 of the container 26 and there receives the pump outlet tube 32 in its open passage end 85 (FIG. 3), and the manifold is further supported on a stand 92 (FIG. 1). Further provided in the manifold 82 are a plurality of spaced outlets 94 which branch from the wax passage 84. The manifold 82 is also jacketed for circulation of heated oil therethrough to keep the wax in the manifold in molten state, with the manifold jacket being in this instance provided in two separate sections 96 and 98, of which jacket section 96 is formed in this instance by two longitudinal through-

passages

100 and 102 in the manifold (FIGS. 3 and 4), of which passage 100 is closed at the wall 56 of the container 26 and has in the end cover 86 a cross-connection 104 with one end of the passage 102 (FIGS. 1 and 4), with the opposite end of this passage 102 receiving a conduit 106 that extends in sealed fashion through the container wall 56 and carries a flow-regulating valve 108 (FIGS. 2 and 3). Leading from the discharge end of this valve 108 is a tube 110 which extends into the jacket 44 of the pump inlet tube 30 near the sealed bottom thereof. The other jacket section 98 is formed in this instance by four longitudinal through-passages 112, 114, 116 and 118 in the manifold (FIG. 4), of which one end of passage 112 is closed at the container wall 56 and its other end is by a crossconnection 120 in the end cover 86 (FIGS. 1 and 4) in communication with the adjacent end of the passage 114, with the opposite end of the latter passage being by a cross-connection 124 in the manifold in communication with the adjacent end of passage 116, while the other end of the latter passage is through a cross-connection in the end cover 86 in communication with the adjacent end of the final passage 118. The opposite end of this final passage 118 receives a conduit 126 which extends in sealed fashion through the wall 56 of the container .26 and carries a flow-regulating valve 128 that discharges oil from the jacket section 98 into the container 26 (FIG. 2). The manifold 82 is provided with a conduit 130 that leads to the jacket passage 112 near its closed end and through which circulating oil enters the jacket section 98, with the latter forming a serpentine path for the circulating oil to its discharge into the container 26 at the valve 128.

With the nozzle casings 88 being in this instance identical, only one casing 88 will be described in detail and with reference to FIGS. 3 and 4. Thus, the casing 88 there shown has a body part 132 and a cover part 134 which at 136 is mounted on the body part 132, with the cover part 134 forming around the body part 132 a jacket 138 which is closed at the bottom by a gasket 140 on the top surface 142 of the manifold on which the casing is mounted. The body 132 has a wax port 144 which at its lower end is in communication with one of the branching wax outlets 94 from the wax passage 84 in the manifold 82, and is at its upper end provided with an injection nozzle 16. interposed in the port 144 is a valve 146 with a stem 148 that passes through a packing 150 in the cover part 134 and carries outside the latter a handle 152 for manipulating the valve 146 into open and closed positions, with this valve being shown in closed position in FIGS. 3 and 4. The jacket 138 is adapted for circulation of heated oil therethrough to keep the wax in the port 144 in molten state. Thus, on releasably clamping a pattern mold (not shown) to the nozzle 16 in injecting relation therewith, and on opening the valve 146, molten wax under injection pressure will be forced into the mold until the same is fully charged, with the wax charge therein being kept under the injection pressure, which may be up to 1000 p.s.i., until the charge is substantially solidified, whereupon the valve 146 is closed and the charged mold removed from the nozzle 16 for subsequent removal of the wax pattern from the mold.

The manifold 82 is advantageously provided in sections 82' of which one or more may be used in the apparatus, depending on how many injection nozzles 16 are to be used at proper spacing from each other afford an operator at each nozzle comfortable working space. Thus, in the present example two manifold sections 82 are joined end-to-end, with each section having end flanges 83 which serve for mounting purposes, to wit, for mounting the section 82' next to the container 26 to the same, for mounting both sections to each other end-toend, and for mounting the cover 86 to the outer end of the section most remote from the container 26. Also, with the wax passage and the jacket passages in each manifold section 82 being through-passages, these passages are continuous with each other in end-to-end mounted sections.

The present invention also contemplates applying to the wax charge in a mold a booster pressure which is much higher than the injection pressure at which the wax is injected into the mold, and may, for example, be 8000 psi. The purpose for applying such booster pressure is greatly to reduce, if not prevent, undesirable shrinkage of the injected wax charge in the course of its solidification in a mold. This is important for many wax patterns which under ordinary injection pressure shrink as much as 12 percent. To this end, each nozzle casing 88 is further provided with a cylinder (FIGS. 2 and 4) having a plunger 162 therein. With these cylinders 160 being identical for all nozzle casings 88, only one of these cylinders will be described in detail with reference to FIG. 4. Thus, the cylinder 160 is with its open end 164 fittedly received in the body part 132 and is through a duct 166 in the latter in communication with the port 144 intermediate the valve 146 and nozzle 16. The cylinder 166 extends with its other end 168 in sealed fashion through an end sleeve 170 in a conduit 172 which with its open end is mounted in the cover part 134 and forms around the cylinder therein a jacket 174 which is part of the casing jacket 138, with the jacket 174 being adapted for circulation of heated oil therethrough to keep wax in the cylinder 160 in molten state. Provisions to-be-described are made to vent the cylinder end 168 and to apply thereto a liquid under considerably higher than the described wax injection pressure, with this higher pressure being the booster pressure referred to. Thus, on venting the cylinder end 168 and opening the valve 146, a mold releasably clamped to the nozzle 16, as well as the cylinder 160 will be charged with wax under injection pressure, whereupon valve 146 is closed and liquid under the stated booster pressure is admitted to the cylinder end 168, with this booster pressure being, through the plunger 162 and the wax in the cylinder 160 and nearby port 144 above valve 146, transmitted to the wax charge in the mold. The booster pressure is thus applied to the wax charge in the mold until the same is substantially solidified without appreciable shrinkage, whereupon the cylinder end 168 is vented and the mold removed from the nozzle. The nozzle casing 88 is then ready for charging another mold with wax and applying the booster pressure to the wax charge in the mold,

For circulation of heated oil through the various jackets, there is provided an oil pump (FIG. 4) the inlet 182 of which is in communication with the tank jacket 22 preferably near its bottom where the oil therein is at or near maximum temperature in the vicinity of the electric heating element 42. The outlet 184 of the pump 180 is in communication with a conduit 186 having continuing

branch conduits

188 and 130, of which branch conduit 188 has further branches that lead to inlets 190 to the cylinder jackets 174 in the nozzle casings 88, while branch conduit 130 leads to the described jacket section 98 in the manifold 82. Heated oil thus delivered to the cylinder jackets 174 flows through the latter into the associated casing jackets 138, with each casing jacket 138 having near its top an overflow pipe 192 which leads to the other described jacket section 96 in the manifold 82, whereby each casing jacket 138 is at all times filled with heated oil substantially to the top, and the jacket section 96 in the manifold 82 is supplied with overflow oil from the casing jackets 138. Oil thus constantly delivered to the manifold jacket section 96 flows through the latter and discharges into the pump inlet jacket 44 through the flow-regulating valve 108 and tube 110, with the heated oil thus delivered to the jacket 44 flowing upwardly therein into the container 26. The major flow of circulating heated oil in the manifold 82 is through the other jacket section 98 therein, with this oil being discharged into the container 26 through the flow-regulating valve 128 (FIG. 2). As already explained, the heated oil thus discharged into the container 26 keeps the latter filled at least to the level of the overflow tube 38 therein, with the oil passing through this overflow tube being discharged into the tank jacket 22. ln the circulation of heated oil through the apparatus in this fashion, the heat transmitted from this oil to the wax in the apparatus is distributed for keeping the wax in molten state at all places, including the wax passage in the wax pump 20 and the wax ports 144 in the nozzle casings 88 wherein even the slightest wax solidification would jeopardize an operation. Also beneficial to this end is heat-zoning of the heated oil in its circulation through the casing jackets 138 and container 26 due to the discharge of oil therefrom through the

respective overflow pipes

192 and 38.

The aforementioned provision for venting the cylinder ends 168 and applying liquid under booster pressure to them involves a pump 200 of presettable output pressure with a bypass 202 to a supply S of operating liquid, preferably oil, through which the pump output is returned to the supply when exceeding the preset output pressure, with the latter pressure being the selected booster pressure (F IG. 4). The pump inlet 204 is in communication with the oil supply S, and the pump outlet 206 has branches 208 which lead to valves 210 each of which is associated with a conduit 212 to the end 168 of the cylinder 160 in a nozzle casing 88, and with a return conduit 214 to the oil supply S. Thus, each cylinder end 168 is vented by shifting the associated valve 210 into the dotted line position (FIG. 4) in which the associated conduit 212 is in communication with the associated return conduit 214, while the same cylinder end 168 is supplied with oil under booster pressure on shifting valve 210 into the full-line position in which conduit 208 is in communication with conduit 212.

Reference is now had to FIGS. 5 and 6 which show a modified nozzle casing 88a in which there is interposed in the wax port 1440 in the body part 132a between the control valve 146a and injection nozzle 16a another valve 220 which is also interposed between the duct 166a and wax port 1440. This other valve 220 is a three-way valve with a diametrical port 222 and a side port 224, with the valves 146a and 220 being operable in a first manner to charge a clamped-on mold at the nozzle 16a and the cylinder 160a simultaneously with wax under the lower injection pressure, and then to apply the higher booster pressure to the wax charge in the mold and being operable in another manner to charge the cylinder 160a with wax at the lower injection pressure in the valve settings of FIG. 5, and then transfer wax from the cylinder to the mold at the higher booster pressure in the valve settings of FIG. 6. For operating the valves 146a and 220 in the aforementioned first manner, valve 146a is opened as in FIG. 5 and valve 220 is shifted into a position in which its diametrical port 222 is in line with the wax port 144a and its side port 224 is open to the duct 1660, for simultaneously charging the mold and cylinder 1600 with wax at the lower injection pressure, and valve 1460 is closed and valve 220 is left in the position just described for applying the higher booster pressure to the wax charge in the mold. The present arrangement of the valves 146a and 220 also permits a third possible mode of operation, namely, to charge the mold with wax at the lower injection pressure and maintain the wax charge under this same injection pressure until substantially solidified. This is achieved by setting valve 200 so that its diametrical port 222 is in line with the wax port 1440 and its side port 224 is out of communication with the duct 166a, and opening the other valve 146a, as will be readily understood.

Reference is now had to FIG. 7 which shows another modified nozzle casing 88b having in its wax port 1441; a single valve 230 which is also interposed between the wax port 144!) and the duct 16612 with the valve 230 having a single port 232. Thus, in the position of the valve 230 as shown. the cylinder l60b is charged with wax at the lower injection pressure. On shifting the valve 230 into its other position in which its port 232 communicates with the duct 166b and with the part of the wax port 144b above the valve and leading to a clamped-on mold on the nozzle 16b, wax may be transferred from the cylinder 16% to the mold at the higher booster pressure. With this arrangement, only one valve, i.e., valve 230, is required to charge a mold with wax directly at the higher booster pressure.

I claim:

1. Wax supplying apparatus for pattern molds, comprising a jacketed tank holding a wax supply and having an opening through which to augment the supply; a pump having a jacketed wax passage with an inlet and an outlet with the inlet being immersed in the wax supply in the tank, and said tank and pump jackets being in communication with each other; a device for circulating a heating medium through said jackets to keep the wax in said tank and passage in molten state; a plurality of valve-controlled wax injection nozzles for molds; and heated conduit means from said pump outlet to said nozzles holding molten wax at an injection pressure applied by the operating pump.

2. Wax supplying apparatus as in claim 1, in which said conduit means is a longitudinal jacketed manifold with wax passages from said pump outlet to said nozzles, with the manifold and pump jackets being also in communication with each other, and said device operating to circulate the heating medium through said jackets to keep the wax in said tank and passages in molten state.

3. Wax supplying apparatus as in claim 2, in which the heating medium is oil, and there is provided in one of said jackets an electric heater for heating the passing oil.

4. Wax supplying apparatus as in claim 3, in which said heater is in said tank jacket, and said device includes an oil pump with intake and output ends of which the intake end is in communication with the oil in the tank jacket and the output end is in communication with the manifold jacket, whereby the oil is circulated from the tank jacket successively through the manifold and pump jackets and back to the tank jacket.

5. Wax supplying apparatus for pattern molds, comprising a molten wax supply; a substantially horizontally disposed jacketed manifold with a longitudinal wax passage and a plurality of outlets, of which said passage is open at one end and closed at its other end, and said outlets are spaced and lead from said passage; a plurality of jacketed casings mounted on said manifold in positions in which the top ends of their jackets extend above said manifold jacket, with each casing having a wax port of which one end is in communication with one of said outlets and the other end is formed as a mold injection nozzle, and being provided in its jacket near said top end thereof with an overflow conduit leading to said manifold jacket, and each of said ports and associated outlet constituting a branch conduit from said passage; a valve in each of said branch conduits operable into open and closed positions; a pump with an inlet and outlet in communication with said wax supply and open passage end, respectively, and operative to supply said passage and branch conduits with molten wax at a given injection pressure; and a device for circulating a heating liquid through said jackets in a direction to supply said manifold jacket with overflow liquid from said casing jackets, for keeping the wax in said passage and branch conduits in molten state.

6. Wax supplying apparatus for pattern molds, comprising a molten wax supply; a manifold formed in sections of which each section has a wax passage open at both ends and a plurality of spaced outlets leading from said passage, and said sections are removably mounted end-to-end with their passages aligned and continuous with each other; a pump with an inlet and outlet, of which said inlet is in communication with said wax supply and said outlet is in communication with the passage in the section nearest said pump; a cover removably mounted at the free end of the section most remote from said pump in closing relation with said passage therein; a plurality of casings mounted on said sections, with each casing having a wax port of which one end is in communication with one of said outlets and the other end is formed as a mold injection nozzle, with each of said ports and associated outlet constitut ing a branch conduit from the associated passage; a valve in each of said branch conduits operable into open and closed positions, and said pump being operative to supply said passages and branch conduits with molten wax at a given injection pressure; and means for heating said sections and casings for keeping the wax therein in molten state.

7. Wax supplying apparatus for pattern molds, comprising a molten wax supply; a manifold with a longitudinal wax passage and a plurality of outlets of which said passage is open at one end and closed at its other end, and said outlets are spaced and lead from said passage; a plurality of casings mounted on said manifold, with each casing having a wax port of which one end is in communication with one of said outlets and the other end is formed as a mold injection nozzle, and a cylinder open at one end to said port; a control valve in each of said ports spaced farther from said nozzle end thereof than the associated open cylinder end, with each valve being operable into open and closed positions; a pump with an inlet and outlet in communication with said wax supply and open passage end, respectively, and operative to supply said passage, outlets and ports with molten wax at a given injection pressure; means for heating said manifold and casings for keeping the wax therein in molten state; a plunger in said cylinder; and means operable to vent the other end of each cylinder and to supply it with fluid under higher pressure than said injection pressure for transmission of said higher pressure through the associated plunger to a wax charge in a mold in injecting relation with the associated nozzle end when the associated control valve is closed.

8. Wax supplying apparatus as in claim 7, in which there is provided another valve in each of said casing ports intermediate the nozzle end and control valve and interposed between said port and open cylinder end, with said other valve being a three-way valve shiftable into positions in which to provide communication between said control valve and open cylinder end, simultaneous communication between said control valve, open cylinder end and nozzle end, and communication between said open cylinder end and nozzle end, respectively.

9. Wax supplying apparatus for pattern molds, comprising a molten wax supply; a manifold with a longitudinal wax passage and a plurality of outlets of which said passage is open at one end and closed at its other end, and said outlets are spaced and lead from said passage; a plurality of casings mounted on said manifold, with each casing having a wax port of which one end is in communication with one of said outlets and the other end is formed as a mold injection nozzle, and a cylinder open at one end and having a plunger therein; a valve in each of said ports; a pump with an inlet and outlet in communication with said wax supply and open passage end, respectively, and operative to supply said passage, outlets and ports with molten wax at a given ejection pressure; means for heating said manifold and casings for keeping the wax therein in molten state, said valve in each casing is also interposed between said open cylinder end and port, with said valve being a two-way valve operable into first and second positions in which to provide communication between the associated wax outlet in the manifold and said open cylinder end, and between said open cylinder end and nozzle end, respectively; and means operable to vent the other end of each cylinder and to supply it with fluid under higher than said injection pressure for transferring a wax charge at said higher pressure from said cylinder to a mold in injecting relation with the associated nozzle end when the associated valve is in said second position.

l0. Wax supplying apparatus for pattern molds, comprising a 'acketed tank holding a wax supply and having a top through w lCh to augment the supply; a container above said tank having a top, sides, and a bottom with a downward tube extension projecting with its lower end into said tank; a pump in said container having an inlet tube and an outlet tube and a wax passage therebetween, of which said outlet tube extends in sealed fashion through a container side, and said inlet tube extends through said tube extension with lateral clearance and into said wax supply, with said tube extension and inlet tube therein forming a ring chamber open to said container; a seal between said lower end of said tube extension and inlet tube to seal said ring chamber from the wax supply; a jacketed wax distributor with a longitudinal wax passage open at one end and closed at the other end, and a plurality of spaced ports branching from said passage and terminating as wax injection nozzles, with said open passage end being in communication with said outlet tube; control valves in said ports operable into open and closed positions; a conduit leading from said distributor jacket into said ring chamber near said sealed end thereof; an overflow tube in said container at a level above said outlet tube and leading to said tank jacket; and a device for circulating a heating liquid through said tank and distributor jackets, conduit and container in a direction to supply said tank jacket with overflow liquid from said container, thereby to keep the wax in said tank, tubes, passages and ports in molten state, and said pump supplying said distributor passage and ports with wax under injection pressure.

11. Wax supplying apparatus as in claim 10, in which said jacket in said distributor is formed in separate sections, with said conduit leading from one of said sections, and the other section being in communication with said container through an aperture in one side thereof below the level of said overflow tube.

l2. Wax supplying apparatus as in claim 10, in which said wax distributor comprises a substantially horizontal jacketed manifold having said longitudinal wax passage and spaced outlets branching from said passage, and a plurality of jacketed casings mounted on said manifold and each having a duct of which one end is in communication with one of said outlets and the other end is formed as an injection nozzle, with said duct and associated outlet constituting one of said ports, and said casings being disposed to extend with the top ends of their jackets above said manifold jacket, and an overflow tube near said top end of each casing jacket and leading to said manifold jacket, with said device also circulating heating liquid through said casing jackets such that said manifold jacket is supplied with overflow liquid from said casing jackets.

l3. Wax supplying apparatus as in claim 12, in which said device includes a pump with an inlet and an outlet of which said inlet is in direct communication with liquid in said tank jacket, and said outlet is in direct communication with said casing jackets, and there is further provided in said tank jacket an electric heater for heating the circulating liquid.

Claims

6. Wax supplying apparatus for pattern molds, comprising a molten wax supply; a manifold formed in sections of which each section has a wax passage open at both ends and a plurality of spaced outlets leading from said passage, and said sections are removably mounted end-to-end with their passages aligned and continuous with each other; a pump with an inlet and outlet, of which said inlet is in communication with said wax supply and said outlet is in communication with the passage in the section nearest said pump; a cover removably mounted at the free end of the section most remote from said pump in closing relation with said passage therein; a plurality of casings mounted on said sections, with each casing having a wax port of which one end is in communication with one of said outlets and the other end is formed as a mold injection nozzle, with each of said ports and associated outlet constituting a branch conduit from the associated passage; a valve in each of said branch conduits operable into open and closed positions, and said pump Being operative to supply said passages and branch conduits with molten wax at a given injection pressure; and means for heating said sections and casings for keeping the wax therein in molten state.

10. Wax supplying apparatus for pattern molds, comprising a jacketed tank holding a wax supply and having a top through which to augment the supply; a container above said tank having a top, sides, and a bottom with a downward tube extension projecting with its lower end into said tank; a pump in said container having an inlet tube and an outlet tube and a wax passage therebetween, of which said outLet tube extends in sealed fashion through a container side, and said inlet tube extends through said tube extension with lateral clearance and into said wax supply, with said tube extension and inlet tube therein forming a ring chamber open to said container; a seal between said lower end of said tube extension and inlet tube to seal said ring chamber from the wax supply; a jacketed wax distributor with a longitudinal wax passage open at one end and closed at the other end, and a plurality of spaced ports branching from said passage and terminating as wax injection nozzles, with said open passage end being in communication with said outlet tube; control valves in said ports operable into open and closed positions; a conduit leading from said distributor jacket into said ring chamber near said sealed end thereof; an overflow tube in said container at a level above said outlet tube and leading to said tank jacket; and a device for circulating a heating liquid through said tank and distributor jackets, conduit and container in a direction to supply said tank jacket with overflow liquid from said container, thereby to keep the wax in said tank, tubes, passages and ports in molten state, and said pump supplying said distributor passage and ports with wax under injection pressure.

12. Wax supplying apparatus as in claim 10, in which said wax distributor comprises a substantially horizontal jacketed manifold having said longitudinal wax passage and spaced outlets branching from said passage, and a plurality of jacketed casings mounted on said manifold and each having a duct of which one end is in communication with one of said outlets and the other end is formed as an injection nozzle, with said duct and associated outlet constituting one of said ports, and said casings being disposed to extend with the top ends of their jackets above said manifold jacket, and an overflow tube near said top end of each casing jacket and leading to said manifold jacket, with said device also circulating heating liquid through said casing jackets such that said manifold jacket is supplied with overflow liquid from said casing jackets.

13. Wax supplying apparatus as in claim 12, in which said device includes a pump with an inlet and an outlet of which said inlet is in direct communication with liquid in said tank jacket, and said outlet is in direct communication with said casing jackets, and there is further provided in said tank jacket an electric heater for heating the circulating liquid.